JP2009014763A - Method of manufacturing toner for electrostatic image development - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing electrostatic image development which is superior in productivity facilitating rinsing treatment (rinsing-filtering-dehydration), by suppressing the generation of small particle diameter particulates sub-generated in the polymerization of a toner. <P>SOLUTION: The method of manufacturing the toner for electrostatic charge image development includes the suspending process for obtaining a suspension liquid that disperses droplet of a polymerization monomer composition, by suspending the polymerization monomer composition containing at least a polymerization monomer and a coloring agent in a water-based dispersion medium containing a dispersion stabilization agent; and the process for obtaining coloring resin particles, by performing suspension of polymerization under the presence of a polymerization initiator concerning the suspending liquid. The content of isolation copper is a copper phthalocyanin pigment of 500 ppm or lower; and when the coloring agent performs suspending polymerization, the suspension liquid contains a small-particle diameter particle suppressing agent of 0.01-1 pt.wt. to the polymerization monomer of 100 pts.wt. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention may be referred to as an electrostatic image developing toner (hereinafter simply referred to as “toner”) used for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing, and the like. More particularly, the present invention relates to a method for producing a toner for developing an electrostatic image having excellent productivity.

  In recent years, there is a growing need for colorization of image forming apparatuses such as copying machines, facsimiles, and printers using electrophotography. In color electrophotography, a reproducibility of a clear color tone is required, and a color toner that can be used for printing a high-definition image such as a photograph is required.

  An image forming apparatus capable of supporting color electrophotography includes three primary colors of cyan (blue), magenta (red), and yellow (yellow), and black (black) toner. The color tone is reproduced by superimposing these four color toners on the surface of the printing paper as necessary and mixing the colors (intermediate color, secondary color).

In order to increase the resolution of an image, it is suitable to employ a spherical toner having a small particle diameter, and a polymerization method has been proposed as a method for producing the toner.
Examples of the method for producing a toner by a polymerization method include suspension polymerization, emulsion aggregation polymerization, and dispersion polymerization. For example, in the suspension polymerization method, first, a polymerizable monomer, a colorant, and other additives as necessary are added to prepare a polymerizable monomer composition. Then, the polymerizable monomer composition is formed into droplets by introducing and dispersing in an aqueous dispersion medium containing a dispersion stabilizer, and applying a high share using a high-speed stirrer or the like. Thereafter, the aqueous dispersion medium in which the polymerizable monomer composition formed in droplets is dispersed is polymerized in the presence of a polymerization initiator, and after being subjected to washing treatment (washing, filtration, dehydration) and drying, the colored resin particles Get.

  In the case of obtaining colored resin particles by a polymerization method, spherical colored resin particles having a small particle diameter are formed at a stage of forming particles (in the polymerization method, a droplet formation stage and a polymerization stage) as compared with the conventional pulverization method. It has a great advantage that it can be formed and the particle size distribution can be adjusted more sharply. However, in recent years, with the further increase in the level of demand for image printing with high resolution and high image quality, attempts have been made to make the particle size of the toner smaller, and new problems have been pointed out even with polymerized toner.

  The above problem is that, in the polymerization process of the toner production method, in addition to the desired colored resin particles, particles having an unnecessary fine particle size are by-produced, thereby improving the toner productivity and the printing performance. It has been pointed out to have an adverse effect. The fine by-product particles are particles of a so-called submicron order having a particle size of less than 0.6 μm and do not contain a colorant (hereinafter referred to as “small particle size fine particles”).

  When fine particles with small particle size are by-produced during the polymerization of the toner, a part of the small particle size fine particles are used as a filter material in the cleaning process (cleaning / filtration / dehydration) when separating the obtained colored resin particles from the aqueous dispersion medium. Since clogging, the cleaning processing efficiency is lowered, which causes a reduction in toner productivity.

  In addition, when toner containing small particle size particles is used for printing, the small particle size particle has a large adhesion force, and thus easily adheres to a member in the developing machine. Filming (sticking) occurs. When filming occurs on the photoconductor in the developing machine, charging failure occurs on the surface of the photoconductor, and a desired electrostatic latent image cannot be formed on the photoconductor, which causes a decrease in printing performance.

  According to the polymerization method, it is possible to easily produce small colored resin particles having a volume average particle diameter Dv of about 3 to 15 μm. However, as the target particle diameter range shifts to the small particle diameter side, Since it approaches the particle size of the small particle size fine particles of the submicron order as described above, it is difficult to separate desired colored resin particles from unnecessary small particle size fine particles. For this reason, it is desired to develop a toner manufacturing method that is excellent in toner productivity and printing performance by suppressing the by-product of small particle size fine particles. Various studies have been conducted to meet the above requirements.

  For example, in Patent Document 1, copper phthalocyanine is used as a colorant and t-butylperoxy-2-ethylhexanoate is used as a polymerization initiator (Japan) for the purpose of suppressing the generation of small particle size by-products during polymerization. A toner manufactured by a polymerization method using a hydroquinone compound as a product manufactured by Yushi Co., Ltd., trade name: Perbutyl O), and a water-soluble polymerization inhibitor (small particle size fine particle inhibitor) is disclosed.

  In Patent Document 2, for the purpose of preventing generation of malodor when printing is performed, copper phthalocyanine as a colorant, a polymerization initiator, and an organic peroxide having a molecular weight of 205 or less and a purity of 90% or more are t. A toner manufactured by a polymerization method using butyl peroxy-2-ethylbutanoate (manufactured by Akzo Nobel, trade name: Trigonox 27, molecular weight: 188, purity: 98%) is disclosed.

  However, according to the study of the present inventor, it has been found in Patent Document 1 that the hydroquinone compound used as the small particle size fine particle inhibitor is not necessarily sufficient in suppressing the by-product of the small particle size fine particles. did. In Patent Document 2, t-butylperoxy-2-ethylbutanoate used as a polymerization initiator is a decomposition product (volatile organic compound) of a polymerization initiator remaining in a toner that can cause odor. ) And the like are highly effective in reducing the residual amount, but it has been found that the effect of suppressing by-product formation of small-sized fine particles is not so high.

  Further, the present inventor examined the method for suppressing the by-product of the small particle size fine particles, and when the toner was produced using the copper phthalocyanine pigment as the colorant, it was released from the copper phthalocyanine pigment. Copper eluting as a copper ion in the solvent (hereinafter referred to as “free copper”) can be a causative substance that by-produces small particle size fine particles, and also inhibits the effect of the small particle size fine particle inhibitor. We have obtained knowledge that it can be a substance to be used.

PCT International Publication No. WO2006-013847 JP 2007-52039 A

  An object of the present invention is to provide a method for producing a toner for developing an electrostatic charge image that suppresses the generation of small-sized fine particles that are by-produced during the polymerization of the toner, is easy to wash (wash, filter, and dehydrate) and has excellent productivity. There is to do.

  The present inventors diligently studied to achieve the above object, and as a colorant, a copper phthalocyanine pigment in which the content of free copper is reduced to a specific amount or less is used. Found that by adding a specific amount of the small particle size fine particle inhibitor, the generation of small particle size fine particles by-produced during the polymerization of the toner can be effectively suppressed, and based on these findings The present invention has been completed.

That is, in the method for producing an electrostatic charge image developing toner of the present invention, a polymerizable monomer composition containing at least a polymerizable monomer and a colorant is suspended in an aqueous dispersion medium containing a dispersion stabilizer. A suspension step for obtaining a suspension in which droplets of the polymerizable monomer composition are dispersed, and suspension polymerization of the suspension in the presence of a polymerization initiator to obtain colored resin particles. A method for producing an electrostatic charge image developing toner comprising a step,
The colorant is a copper phthalocyanine pigment having a free copper content of 500 ppm or less,
When the suspension polymerization is performed, the suspension contains 0.01 to 1 part by weight of the small particle size inhibitor with respect to 100 parts by weight of the polymerizable monomer. This is a method for producing an image developing toner.

  According to the method for producing a toner for developing an electrostatic charge image of the present invention as described above, the generation of small particle size fine particles that are by-produced during the polymerization of the toner can be effectively suppressed, and washing treatment (washing, filtration, dehydration) can be performed. ) And a method for producing a toner for developing an electrostatic image having excellent productivity.

The method for producing a toner for developing an electrostatic image of the present invention comprises suspending a polymerizable monomer composition containing at least a polymerizable monomer and a colorant in an aqueous dispersion medium containing a dispersion stabilizer. Suspension step in which droplets of the polymerizable monomer composition are dispersed, and a step of obtaining colored resin particles by subjecting the suspension to suspension polymerization in the presence of a polymerization initiator A method for producing a toner for developing an electrostatic charge image comprising:
The colorant is a copper phthalocyanine pigment having a free copper content of 500 ppm or less,
When the suspension polymerization is performed, the suspension contains 0.01 to 1 part by weight of the small particle size inhibitor with respect to 100 parts by weight of the polymerizable monomer. is there.

  Hereinafter, a method for producing the toner for developing an electrostatic charge image of the present invention will be described.

(1) Preparation Step of Polymerizable Monomer Composition First, a polymerizable monomer composition, a colorant, and, if necessary, other additives such as a charge control agent are mixed and dissolved to form a polymerizable monomer composition. The product is prepared. The mixing at the time of preparing the polymerizable monomer composition is performed using, for example, a media type dispersing machine.

In the present invention, the polymerizable monomer means a monomer having a polymerizable functional group. A monovinyl monomer is preferably used as the main component of the polymerizable monomer. Examples of the monovinyl monomer include styrene; styrene derivatives such as vinyl toluene and α-methylstyrene; acrylic acid and methacrylic acid; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, acrylic acid 2 Acrylic esters such as ethylhexyl and dimethylaminoethyl acrylate; methacrylic esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and dimethylaminoethyl methacrylate; acrylamide And amide compounds such as methacrylamide; olefins such as ethylene, propylene, and butylene; and the like. The above monovinyl monomers can be used alone or in combination of two or more.
Of the monovinyl monomers, styrene, styrene derivatives, acrylic acid esters, and methacrylic acid esters are preferably used.

In order to improve the storage stability (blocking resistance) of the toner as a part of the polymerizable monomer, it is preferable to use any crosslinkable polymerizable monomer together with the monovinyl monomer. A crosslinkable polymerizable monomer refers to a monomer having two or more polymerizable functional groups. Examples of the crosslinkable polymerizable monomer include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof; ethylenically unsaturated carboxylic acid esters such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate; N , N-divinylaniline, and divinyl compounds such as divinyl ether; compounds having three or more vinyl groups such as trimethylolpropane trimethacrylate and dimethylolpropane tetraacrylate; The crosslinkable polymerizable monomers may be used alone or in combination of two or more.
In the present invention, the crosslinkable polymerizable monomer may be added at the stage of forming droplets of the polymerizable monomer composition in the aqueous dispersion medium in the suspension step.
In the present invention, it is desirable to use the crosslinkable polymerizable monomer in a proportion of usually 0.1 to 5 parts by weight, preferably 0.3 to 2 parts by weight, with respect to 100 parts by weight of the monovinyl monomer. .

Further, as a part of the polymerizable monomer, it is preferable to use an arbitrary macromonomer together with the monovinyl monomer in order to improve the balance between the storage stability of the toner and the low-temperature fixability. The macromonomer is a reactive oligomer or polymer having a polymerizable carbon-carbon unsaturated bond at the end of the molecular chain and having a number average molecular weight (Mn) of usually 1,000 to 30,000. . As the macromonomer, it is preferable to use an oligomer or polymer having a Tg higher than the glass transition temperature (Tg) of a polymer (binder resin) obtained by polymerizing a polymerizable monomer.
In the present invention, the proportion of the macromonomer is usually 0.01 to 10 parts by weight, preferably 0.03 to 5 parts by weight, and more preferably 0.1 to 2 parts by weight with respect to 100 parts by weight of the monovinyl monomer. It is desirable to use in.

In the present invention, a copper phthalocyanine pigment having a free copper content reduced to a specific amount or less is used as a colorant.
In the present invention, “free copper” means that the copper phthalocyanine pigment is not incorporated as a central metal of the copper phthalocyanine compound and is present as an impurity in the copper phthalocyanine pigment in the production process of the copper phthalocyanine pigment. When dispersed, it means copper that is liberated from the pigment and eluted into the solvent as copper ions.

In the present invention, “copper phthalocyanine pigment” refers to a complex formed by substituting two hydrogen atoms at the center of a phthalocyanine compound having a cyclic structure with a copper ion.
In the present invention, the “copper phthalocyanine pigment” is a generic term for an unsubstituted copper phthalocyanine pigment having no substituent such as a halogen atom and a substituted copper phthalocyanine pigment having a substituent such as a halogen atom.

Examples of the copper phthalocyanine pigment used in the present invention include C.I. I. Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6 and other unsubstituted copper phthalocyanine pigments, and C.I. I. And substituted copper phthalocyanine pigments such as Pigment Green 7 and 36.
Among these, unsubstituted copper phthalocyanine pigments are preferred because of vivid color tone reproduction, and C.I. I. Pigment Blue 15: 3 and 15: 4 are particularly preferably used.

The copper phthalocyanine pigment used in the present invention is a copper phthalocyanine pigment having a free copper content reduced to 500 ppm or less, preferably 300 ppm or less, more preferably 200 ppm or less.
When the content of the free copper exceeds the above range, the generation of small particle size by-product during polymerization cannot be sufficiently suppressed, and when performing the washing treatment (washing / filtration / dehydration) In addition, problems such as clogging occur, and not only the toner productivity is lowered, but also the printing performance of the obtained toner may be adversely affected.

In the present invention, the method for controlling the content of free copper contained in the copper phthalocyanine pigment is not particularly limited as long as the content of free copper can be reduced to a specific amount or less (500 ppm or less). Can be used.
As an example of a method for controlling the content of free copper, first, phthalic anhydride, urea, and copper (I) chloride are added to a high-boiling solvent, and heated in the presence of a catalyst while stirring to prepare. Obtain a solution. The obtained prepared solution is subjected to methanol washing, dilute acid / dilute alkali treatment, and water washing to obtain a crude copper phthalocyanine pigment (crude).
The obtained crude copper phthalocyanine pigment is gradually added to concentrated sulfuric acid and dissolved. The obtained concentrated sulfuric acid solution is gradually added to 5 L of ice water to precipitate copper phthalocyanine pigment crystals, which are washed with water to obtain a purified copper phthalocyanine pigment. Further, sodium chloride and diethylene glycol are added to the obtained purified copper phthalocyanine pigment, and grinding is performed while heating using a kneader such as a kneader to obtain a product. A copper phthalocyanine pigment in which the content of free copper is reduced to a specific amount or less (500 ppm or less) is obtained by performing operations of dilute acid treatment and water washing on the obtained product.

  In the present invention, the copper phthalocyanine pigment used as a colorant is desirably used in a ratio of 2 to 10 parts by weight, preferably 3 to 8 parts by weight, based on 100 parts by weight of the monovinyl monomer.

As another additive, a release agent is preferably used in order to improve the releasability of the toner from the fixing roll.
The release agent is not particularly limited as long as it is generally used as a release agent for toner. For example, polyolefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and low molecular weight polybutylene; candelilla, carnauba Natural wax such as paraffin, microcrystalline and petrolatum; mineral wax such as montan, ceresin and ozokerite; synthetic wax such as Fischer-Tropsch wax; pentaerythritol tetramyristate; Pentaerythritol esters such as pentaerythritol tetrapalmitate, pentaerythritol tetrastearate, and pentaerythritol tetralaurate, and dipentaerythritol hexami State, dipentaerythritol hexa palmitate, and polyhydric alcohol ester compounds such as dipentaerythritol esters such as dipentaerythritol hexa laurate; and the like. These release agents may be used alone or in combination of two or more.
In this invention, it is desirable to use a mold release agent in the ratio of 0.1-30 weight part normally with respect to 100 weight part of monovinyl monomers, Preferably it is 1-20 weight part.

As other additives, various charge control agents having positive chargeability or negative chargeability can be used in order to improve the chargeability of the toner.
The charge control agent is not particularly limited as long as it is generally used as a charge control agent for toners. However, in the present invention, from the viewpoint of obtaining a positively chargeable toner, a positively chargeable charge control agent is used. It is preferable to use it. Furthermore, among the positively chargeable charge control agents, the toner has high compatibility with the polymerizable monomer and can impart stable chargeability (charge stability) to the toner particles. It is preferable to use a resin.
As the positively chargeable charge control resin, for example, various commercially available products can be used. As the products made by Fujikura Kasei, FCA-161P (: trade name, styrene / acrylic resin), FCA-207P (: trade name) , Styrene / acrylic resin), FCA-201-PS (: trade name, styrene / acrylic resin), and the like.
In the present invention, it is desirable to use the charge control agent in a proportion of usually 0.01 to 10 parts by weight, preferably 0.03 to 8 parts by weight, with respect to 100 parts by weight of the monovinyl monomer.

It is preferable to use a molecular weight modifier as another additive.
The molecular weight modifier is not particularly limited as long as it is generally used as a molecular weight modifier for toner. For example, t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, and 2,2, Mercaptans such as 4,6,6-pentamethylheptane-4-thiol; tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, N, N′-dimethyl-N, N′-diphenylthiuram disulfide, N, And thiuram disulfides such as N′-dioctadecyl-N and N′-diisopropylthiuram disulfide; These molecular weight modifiers may be used alone or in combination of two or more.
In the present invention, the molecular weight modifier may be added at the stage of forming droplets of the polymerizable monomer composition in the aqueous dispersion medium in the suspension step.
In the present invention, it is desirable to use the molecular weight modifier in a proportion of usually 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, with respect to 100 parts by weight of the monovinyl monomer.

(2) Suspension step for obtaining a suspension (droplet formation step)
(1) The polymerizable monomer composition obtained by the preparation step of the polymerizable monomer composition is suspended in an aqueous dispersion medium containing a dispersion stabilizer, and a suspension (polymerizable monomer composition) is obtained. To obtain a polymer composition dispersion). Here, the suspension means that droplets of the polymerizable monomer composition are formed in an aqueous dispersion medium. Dispersion treatment for forming droplets is, for example, an in-line type emulsifier / disperser (trade name: Milder, manufactured by Taiheiyo Kiko Co., Ltd.), a high-speed emulsifier / disperser (trade name: TK homomixer, manufactured by Tokushu Kika Kogyo Co., Ltd. MARK II type) and the like capable of strong stirring.

In the suspending step of the present invention, the aqueous dispersion medium contains a dispersion stabilizer in order to control the particle diameter of the colored resin particles and improve the circularity.
The aqueous dispersion medium may be water alone, but may be used in combination with a solvent that can be dissolved in water, such as lower alcohol and lower ketone.

  Examples of the dispersion stabilizer include sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate and magnesium carbonate; phosphates such as calcium phosphate; metals such as aluminum oxide and titanium oxide. Oxides and metal compounds such as metal hydroxides such as aluminum hydroxide, magnesium hydroxide, and ferric hydroxide; water-soluble polymer compounds such as polyvinyl alcohol, methyl cellulose, and gelatin; anionic surfactants , Organic polymer compounds such as nonionic surfactants and amphoteric surfactants; Among these, metal hydroxides are preferable, and magnesium hydroxide used in a pH range of usually 7.5 to 11 is particularly preferable.

Among the above dispersion stabilizers, a dispersion stabilizer containing a colloid of a hardly water-soluble metal hydroxide (a hardly water-soluble inorganic compound) that is soluble in an acid solution is preferably used.
The dispersion stabilizers can be used alone or in combination of two or more.
The amount of the dispersion stabilizer added is preferably 0.1 to 20 parts by weight and more preferably 0.2 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer.

In the present invention, a specific amount of a small particle size fine particle inhibitor is used in order to effectively suppress the generation of small particle size fine particles by-produced during the polymerization of the toner.
In the present invention, the “small particle size fine particle inhibitor” is a polymerization property that exists (elutes) in the aqueous dispersion medium (in the aqueous phase) in the process of forming droplets of the polymerizable monomer composition. It refers to a compound having an effect of trapping radicals derived from monomers and / or radicals derived from a polymerization initiator to suppress the generation of small particle diameter fine particles by-produced during polymerization.

  The small particle size inhibitor used in the present invention is a small particle size inhibitor having a structure represented by the following formula 1, formula 2, or formula 3; It is preferable because the effect of suppressing the generation is high.

(In the above formulas 1 to 3, R is OX, SO ₃ X, CO ₂ X, or CH═CHCO ₂ X, and X is hydrogen or metal.)

  Examples of the metal of the metal salt of the polyhydric phenol compound represented by the above formulas 1 to 3 include monovalent metals such as lithium, sodium, and potassium; polyvalent metals such as magnesium, calcium, and aluminum; The metal of the metal salt of the polyhydric phenol compound is a monovalent metal from the viewpoint of compatibility (solubility) between the metal salt of the polyhydric phenol compound (small particle size fine particle inhibitor) and the aqueous dispersion medium (aqueous phase). It is preferable that

  Examples of the small particle size fine particle inhibitor represented by the above formula 1 include hydroxyhydroquinone, hydroquinonesulfonic acid, hydroquinonecarboxylic acid, and metal salts thereof. Examples of the small particle size inhibitor represented by the above formula 2 include caffeic acid, 3,4-dihydroxybenzoic acid, 3,4-dihydroxybenzenesulfonic acid, and metal salts thereof. Examples of the small particle size inhibitor represented by the above formula 3 include pyrogallol, 2,3-dihydroxybenzoic acid, 2,3-dihydroxybenzenesulfonic acid, 2,3-dihydroxycinnamic acid, and these A metal salt etc. are mentioned. Among these small particle size fine particle inhibitors, pyrogallol, hydroxyhydroquinone, and caffeic acid are preferably used, and pyrogallol is particularly preferably used when a toner is produced using a copper phthalocyanine pigment as a colorant.

  The timing of adding the small particle size inhibitor used in the present invention is not particularly limited as long as the suspension can contain a specific amount of the small particle size inhibitor when performing suspension polymerization. The particle size fine particle inhibitor is preferably added to the aqueous dispersion medium rather than being added to the polymerizable monomer composition at the time of preparing the polymerizable monomer composition. The timing for adding the small particle size fine particle inhibitor to the aqueous dispersion medium is before or after adding the dispersion stabilizer, before or after adding the polymerizable monomer composition, or polymerization initiator. The small particle size inhibitor may be added to the aqueous dispersion medium at any stage before or after the addition of, but it is highly effective in suppressing the generation of small particle size particles by-produced during polymerization. It is particularly preferable that the polymerizable monomer composition is added to the aqueous dispersion medium after the droplet formation, that is, to the suspension.

The addition amount of the small particle size inhibitor used in the present invention is 0.01 to 1 part by weight and 0.03 to 0.8 part by weight with respect to 100 parts by weight of the polymerizable monomer. Preferably, it is 0.05-0.5 weight part.
When the addition amount of the small particle size inhibitor used in the present invention is less than the above range, the polymerization reaction of the polymerizable monomer eluted (present) in the aqueous dispersion medium (in the aqueous phase) is performed. In some cases, it cannot be suppressed (stopped), and generation of small-sized fine particles by-produced during polymerization cannot be sufficiently suppressed. On the other hand, if the addition amount of the small particle size fine particle inhibitor used in the present invention exceeds the above range, the desired polymerization reaction of the polymerizable monomer composition is suppressed, and the polymerizable monomer is polymerized. In some cases, a large amount may remain in the toner.

The polymerization initiator used in the present invention is preferably an organic peroxide. Organic peroxides are generally classified into seven types: hydroperoxide compounds, dialkyl peroxide compounds, peroxyester compounds, diacyl peroxide compounds, peroxydicarbonate compounds, peroxyketal compounds, and ketone peroxide compounds. Is done.
Among these, the polymerization initiator used in the present invention is more preferably a peroxyester compound represented by the following formula 4.

(In the above formula 4, R ¹ and R ² are any alkyl group having 1 to 10 carbon atoms.)

R ¹ in the above formula 4 is preferably an alkyl group having 8 or less carbon atoms, and more preferably an alkyl group having 7 or less carbon atoms. Specific examples of R ¹ include i-propyl, 1-methylpropyl, 1-ethylpropyl; 1-methylbutyl, 2-methylbutyl, 1-ethylbutyl, 2-ethylbutyl; 1-methylpentyl, 2-methylpentyl, 1- Examples include ethylpentyl, 2-ethylpentyl; 1-methylhexyl, 2-methylhexyl, 1-ethylhexyl, 2-ethylhexyl; and the like, and 1-ethylpentyl is particularly preferable.
In addition, R ² in the above formula 4 is preferably an alkyl group having 10 or less carbon atoms, and more preferably an alkyl group having 6 or less carbon atoms. Specific examples of R ² include t-butyl, t-hexyl, t-amyl and the like, and t-butyl is particularly preferable.

  Specific examples of the peroxyester compound having the structure represented by the above formula 4 include t-butylperoxy-2-ethylbutanoate (the following formula 5) and t-butylperoxy-2-ethylhexanoate. Ate (Formula 6 below) and the like. Among these, t-butylperoxy-2-ethylbutanoate is used from the viewpoint of reducing the residual amount of a decomposition product (volatile organic compound) of the polymerization initiator remaining in the toner that may cause odor. T-Butylperoxy-2-ethylhexanoate is preferable from the viewpoint of suppressing the generation of small-sized fine particles by-produced during polymerization. As the polymerization initiator of the present invention, t-butylperoxy-2-ethylhexanoate is more preferably used.

  The timing of adding the polymerization initiator used in the present invention is not particularly limited as long as the suspension can contain a polymerization initiator when performing suspension polymerization, but the polymerization initiator is a polymerizable monomer. It is more preferable that it is added to the aqueous dispersion medium after the droplets are formed, rather than being added to the polymerizable monomer composition at the time of preparation of the body composition.

  The amount of the polymerization initiator used in the present invention is preferably 0.1 to 20 parts by weight, more preferably 0.3 to 15 parts by weight, based on 100 parts by weight of the polymerizable monomer. More preferably, it is 1 to 10 parts by weight.

(3) Polymerization step The suspension (aqueous dispersion medium containing droplets of the polymerizable monomer composition) obtained in the step (2) of obtaining a suspension in the presence of a polymerization initiator, Suspension polymerization is performed to obtain an aqueous dispersion of colored resin particles. In the polymerization step, in order to perform the polymerization in a state where the droplets of the polymerizable monomer composition are stably dispersed, the polymerization reaction is carried out while carrying out the dispersion treatment by stirring following the step (2) of obtaining the suspension. It is preferable to proceed.

  In the polymerization step, the polymerization temperature is preferably 50 ° C. or higher, and more preferably 60 to 98 ° C. Further, the polymerization time is preferably 1 to 20 hours, and more preferably 2 to 15 hours.

In the present invention, when a copper phthalocyanine pigment having a free copper content reduced to a specific amount or less is used as a colorant and suspension polymerization is performed, the suspension contains a specific amount of a small particle size fine particle inhibitor. By adding in such a manner, it is possible to effectively suppress the generation of small-sized fine particles that are by-produced during the polymerization of the toner.
For this reason, the average number of small particle size fine particles per colored resin particle obtained through the polymerization step can be preferably 100 or less, and more preferably 80 or less. More preferably, it can be 50 or less.

Here, the average number of small particle size fine particles per colored resin particle refers to an aqueous dispersion containing colored resin particles after the polymerization step, prepared as a sample for a scanning electron microscope (SEM), and scanned. Using the electron microscope, the image of the adjusted sample was photographed with 5 fields of view at a magnification of 5,000 times, and 5 colored resin particles were randomly selected in each image, and the surface of these 25 colored resin particles. This is a value obtained by counting the number of small particle size fine particles observed in (1) and calculating the average number of small particle size fine particles per colored resin particle.
The number of small particle size fine particles per colored resin particle can be measured using a commercially available scanning electron microscope. For example, a field emission scanning electron microscope (trade name: S-4700, manufactured by Hitachi, Ltd.). ).

In the present invention, a colored resin particle obtained by the polymerization step is used as a core layer, and a so-called core-shell type (or “capsule type”) colored resin obtained by forming a shell layer different from the core layer on the outer side thereof. It is preferable to use particles.
The core-shell type colored resin particles provide a balance between lowering the fixing temperature of toner and preventing aggregation during storage by coating a core layer made of a material having a low softening point with a material having a higher softening point. Can be taken.

  There is no restriction | limiting in particular as a method of manufacturing the said core-shell type colored resin particle, It can manufacture by a conventionally well-known method. An in situ polymerization method and a phase separation method are preferable from the viewpoint of production efficiency.

A method for producing core-shell type colored resin particles by in situ polymerization will be described below.
By adding a polymerizable monomer for forming a shell layer (polymerizable monomer for shell) and a polymerization initiator for shell into an aqueous dispersion medium in which colored resin particles are dispersed, and performing polymerization. Core-shell type colored resin particles can be obtained.

  As the polymerizable monomer for the shell, the same polymerizable monomer as described above can be used. Among them, it is preferable to use monomers such as styrene and methyl methacrylate that can produce a polymer having a Tg of more than 80 ° C. alone or in combination of two or more.

Examples of the shell polymerization initiator used for the polymerization of the shell polymerizable monomer include potassium persulfate and persulfate metal salts such as ammonium persulfate; 2,2′-azobis (2-methyl-N- (2-hydroxy Water-soluble azo compounds such as ethyl) propionamide) and 2,2′-azobis- (2-methyl-N- (1,1-bis (hydroxymethyl) 2-hydroxyethyl) propionamide); Mention may be made of initiators.
The addition amount of the polymerization initiator for shell used in the present invention is preferably 0.1 to 30 parts by weight, more preferably 1 to 20 parts by weight with respect to 100 parts by weight of the polymerizable monomer for shell. preferable.

  The polymerization temperature of the shell layer is preferably 50 ° C. or higher, and more preferably 60 to 95 ° C. The polymerization time for the shell layer is preferably 1 to 20 hours, more preferably 2 to 15 hours.

(4) Washing, filtration, dehydration, and drying steps The aqueous dispersion of colored resin particles obtained by the above (3) polymerization step is carried out according to a conventional method, and a series of operations of washing, filtration, and dehydration are performed as necessary. Repeated several times, and the resulting solid is dried to obtain colored resin particles.

First, in order to remove the dispersion stabilizer remaining in the aqueous dispersion medium of the colored resin particles, washing is performed by adding an acid or an alkali to the aqueous dispersion of the colored resin particles.
When the dispersion stabilizer used is an acid-soluble inorganic compound, an acid is added to the colored resin particle aqueous dispersion, while the dispersion stabilizer used is an alkali-soluble inorganic compound. In this case, an alkali is added to the colored resin particle aqueous dispersion.

  When an acid-soluble inorganic compound is used as the dispersion stabilizer, it is preferable to add an acid to the aqueous dispersion of colored resin particles and perform acid washing until the pH is 6.5 or lower. As the acid added in the acid washing, inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid; organic acids such as formic acid and acetic acid; and the like can be used. Among these, sulfuric acid is particularly preferable because the removal efficiency of the dispersion stabilizer is good and the burden on the toner production facility is small.

After washing with an acid or alkali added to the aqueous dispersion of colored resin particles obtained by the polymerization step, filtration and separation are performed, and ion-exchanged water is added to the resulting solid to reslurry. Then, washing treatment (washing, filtration, dehydration) with a washing solution such as water is repeated several times, and the solid content obtained is dried to obtain colored resin particles.
There are no particular limitations on the methods for the washing treatment and the drying treatment, and various known methods can be used. Examples of the apparatus used for the washing treatment include peeler centrefuge and siphon peeler centrefuge. Examples of the method used in the method include vacuum drying, air flow drying, and a super dryer.

(5) Colored resin particles Hereinafter, the colored resin particles constituting the toner will be described. The colored resin particles described below include both core-shell type and non-core type.

From the viewpoint of image reproducibility, the volume average particle diameter Dv of the colored resin particles obtained by the production method of the present invention is preferably 3 to 15 μm, more preferably 4 to 12 μm, and 5 to 9 μm. More preferably.
When the volume average particle diameter Dv of the colored resin particles is less than the above range, the fluidity of the toner is lowered, the image quality is liable to be deteriorated due to fogging, and the printing performance may be adversely affected. On the other hand, when the volume average particle diameter Dv of the colored resin particles exceeds the above range, the resolution of the obtained image tends to be lowered, and the printing performance may be adversely affected.

In addition, the particle size distribution (Dv / Dp), which is the ratio of the volume average particle size (Dv) and the number average particle size (Dp), of the colored resin particles of the present invention is 1.0 to 1.3 is preferable, and 1.0 to 1.2 is more preferable.
When the particle size distribution (Dv / Dp) of the colored resin particles exceeds the above range, the fluidity of the toner is lowered, the image quality is liable to be deteriorated due to fogging, and the printing performance may be adversely affected. is there.
The volume average particle diameter Dv and the number average particle diameter Dp of the colored resin particles are values measured using a particle size measuring machine.

From the viewpoint of image reproducibility, the average circularity of the colored resin particles obtained by the production method of the present invention is preferably 0.96 to 0.995, and more preferably 0.97 to 0.995. .
When the average circularity of the colored resin particles is less than the above range, the fine line reproducibility of printing tends to be lowered, and the printing performance may be adversely affected.

In the present invention, “circularity” is defined as a value obtained by dividing the circumference of a circle having the same projected area as the particle image by the circumference of the projected image of the particle. The average circularity in the present invention is used as a simple method for quantitatively expressing the shape of the particles, and is an index indicating the degree of unevenness of the colored resin particles. The average circularity is determined by the colored resin particles. 1 is shown in the case of a perfect sphere, and the value becomes smaller as the surface shape of the colored resin particles becomes more complicated. For the average circularity, the circularity (Ci) of each particle measured for a particle group having an equivalent circle diameter of 0.6 μm or more was determined for each of n particles from the following calculation formula 1, and then averaged from the following calculation formula 2. Obtain the circularity (Ca).
Formula 1:
Circularity (Ci) = perimeter of circle equal to projected area of particle / perimeter of projected particle image

In the above calculation formula 2, fi is the frequency of particles having a circularity (Ci).
The circularity can be measured using a flow type particle image analyzer “FPIA-2000”, “FPIA-2100”, “FPIA-3000”, etc. manufactured by Sysmex Corporation.

(6) Toner The colored resin particles obtained in the present invention may be used as they are, or by using colored resin particles and carrier particles (ferrite, iron powder, etc.), but the chargeability, fluidity, and storage of the toner. From the viewpoint of adjusting properties and the like, a high-speed stirrer (for example, trade name: FM mixer (manufactured by Mitsui Mining Co., Ltd.)) may be used to mix the external additives with the colored resin particles to form a one-component toner A two-component developer may be prepared by mixing colored resin particles with an external additive and further carrier particles.

External additives include inorganic fine particles composed of silica, titanium oxide, aluminum oxide, zinc oxide, tin oxide, calcium carbonate, calcium phosphate, cerium oxide, etc .; polymethyl methacrylate resin, silicone resin, melamine resin, etc. Organic fine particles; and the like. Among these, inorganic fine particles are preferable, and among inorganic fine particles, silica and titanium oxide are preferable, and silica is particularly preferable. The above external additives can be used alone, but it is preferable to use two or more kinds in combination.
In the present invention, it is desirable to use the external additive in a proportion of usually 0.1 to 6 parts by weight, preferably 0.2 to 5 parts by weight with respect to 100 parts by weight of the colored resin particles.

  When the toner produced through the steps (1) to (6) is subjected to suspension polymerization using copper phthalocyanine having a free copper content reduced to a specific amount or less as a colorant, However, by adding a small particle size fine particle inhibitor so as to contain a specific amount, the polymerization reaction of the polymerizable monomer present (eluting) in the aqueous dispersion medium (in the aqueous phase) can be suppressed. Generation of small particle size by-product during toner polymerization can be effectively suppressed, cleaning treatment (washing, filtration, dehydration) becomes easy, toner productivity is excellent, and printing performance is also excellent. Toner.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited only to these examples. Parts and% are based on weight unless otherwise specified.
The test methods performed in the examples and comparative examples are as follows.

(Evaluation methods)
(1) Measurement of free copper 1 g of a measurement sample (copper phthalocyanine pigment) was accurately weighed, taken into a 50 ml stoppered Erlenmeyer flask, added with 30 ml of 0.1 M hydrochloric acid aqueous solution, sealed, and shaker (manufactured by IWAKI, (Trade name: KM SHAKER) was shaken for 1 hour under shaking conditions of 300 times / minute.
The aqueous hydrochloric acid solution containing the copper phthalocyanine pigment after shaking was filtered using a glass filter, and 45 ml of 0.1 M aqueous hydrochloric acid solution was added to 5 ml of the obtained filtrate to dilute it 10 times to prepare a sample solution.
About the prepared sample solution, the absorption spectrum of the free copper contained in the sample solution is measured using a polarization Zeeman atomic absorption meter (trade name: Z-5010, manufactured by Hitachi, Ltd.), and the free contained in the sample solution. The copper content was calculated and calculated by converting to the free copper content contained in the copper phthalocyanine pigment.

(2) Colored resin particles (2-1) Volume average particle size Dv and particle size distribution Dv / Dp
About 0.1 g of a measurement sample (colored resin particles) was weighed and taken in a beaker, and 0.1 ml of an alkylbenzene sulfonic 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.

(2-2) Average circularity Into a container, 10 ml of ion-exchanged water is put in advance, 0.02 g of a surfactant (alkylbenzenesulfonic acid) as a dispersant is added, and 0.02 g of colored resin particles is further added. Then, the dispersion treatment was performed with an ultrasonic disperser at 60 W for 3 minutes. The concentration of the colored resin particles at the time of measurement is adjusted to be 3,000 to 10,000 particles / μl, and 1,000 to 10,000 colored resin particles having an equivalent circle diameter of 0.4 μm or more are flow-type particle images. Measurement was performed using an analyzer (trade name: FPIA-2100, manufactured by Simex Corporation). The average circularity was determined from the measured value.
The circularity is shown in the following calculation formula 1, and the average circularity is an average of the circularity.
Formula 1:
(Circularity) = (Perimeter of circle equal to projected area of particle) / (Perimeter of particle projection image)

(3) Average number of fine particles having a small particle diameter 1 ml of 10% H ₂ SO ₄ was added to 3 ml of the aqueous dispersion containing the colored resin particles after the polymerization step to completely dissolve the dispersion stabilizer. 2 ml of this solution was dropped on a filter paper (manufactured by Advantech Toyo Co., Ltd., trade name: No. 2), filtered, and air-dried to prepare a sample for a scanning electron microscope (SEM).
Platinum deposition is performed on the air-dried colored resin particles, and scanning is performed using a field emission scanning electron microscope (manufactured by Hitachi, Ltd., trade name: S-4700) with an acceleration voltage of 5 kV and 5,000 times magnification. Observation with an electron microscope (SEM).
For each sample, five fields of view were taken at random, five colored resin particles were randomly selected in each image, and the number of small particle size particles observed on the surface of these 25 colored resin particles was counted. It was. From this, the average number of small particle diameter fine particles per colored resin particle was calculated.

(Method for producing copper phthalocyanine pigment)
(Production Example 1)
30 parts of phthalic anhydride as a raw material, 45 parts of urea, and 0.06 part of ammonium molybdate as a catalyst are added to 90 parts of Solvesso 150 (trade name, manufactured by ExxonMobil), which is an aromatic high boiling point solvent. The temperature was gradually raised while stirring, and 5.3 parts of copper (I) chloride as a raw material was added at 150 ° C., the temperature was raised to 175 ° C. with further stirring, and the resulting solution was reacted at this temperature for 4 hours. Obtained.

  The prepared solution obtained above was separated by filtration, then washed with methanol, then boiled with 2% hydrochloric acid and 2% aqueous sodium hydroxide for 1 hour, and separated by filtration. Next, after washing with water (washing, filtration, dehydration), the obtained solid was dried to obtain 26.7 parts of an unpurified copper phthalocyanine pigment.

  25 parts of the unpurified copper phthalocyanine pigment obtained as described above was gradually added to 250 parts of 95% concentrated sulfuric acid with stirring and dissolved. Next, the temperature was raised to 70 ° C., and the mixture was stirred at this temperature for 1 hour to be completely dissolved. Thereafter, this concentrated sulfuric acid solution was gradually added to 5 L of ice water to precipitate a crystal of a copper phthalocyanine pigment, followed by separation by filtration. Next, after washing with water (washing, filtration, dehydration), the obtained solid was dried to obtain 23.8 parts of purified copper phthalocyanine pigment.

  1400 parts of sodium chloride and 400 parts of diethylene glycol are added to 400 parts of the purified copper phthalocyanine pigment (CI Pigment Blue 15: 3) obtained as described above, and a pressure kneader (made by Toshin Co., Ltd.), which is a kneading machine, is added. The contents were ground for 6 hours while maintaining the temperature of the contents at 80 to 100 ° C. The product obtained by trituration was treated with dilute acid and filtered off. Next, washing treatment (washing, filtration, dehydration) with water was performed, and the obtained solid content was dried to produce a fine purified copper phthalocyanine pigment having a free copper content of 100 ppm.

(Production Example 2)
22.7 parts of the copper phthalocyanine pigment produced in Production Example 1 and a commercially available copper phthalocyanine pigment (CI Pigment Blue 15: 3) (Dainippon Ink Chemical Co., Ltd., trade name: GC-TF, containing free copper) (Amount: 2470 ppm) 1 part is stirred and mixed using a high-speed stirrer (trade name: FM mixer, manufactured by Mitsui Mining Co., Ltd.) and uniformly dispersed, and a fine purified copper phthalocyanine having a free copper content of 200 ppm A pigment was prepared.

Example 1
75 parts of styrene and 25 parts of n-butyl acrylate as a monovinyl monomer, 5 parts of the copper phthalocyanine pigment produced in Production Example 1 as a cyan colorant, and a charge control resin (manufactured by Fujikura Kasei Co., Ltd., trade name: FCA-) as a charge control agent 161P, styrene / acrylic resin) 1 part and 5 parts of dipentaerythritol hexamyristate as a release agent were stirred and mixed with a stirrer, and uniformly dispersed to obtain a polymerizable monomer composition.

  On the other hand, at room temperature, in an aqueous solution in which 11 parts of magnesium chloride (water-soluble polyvalent metal salt) is dissolved in 200 parts of ion-exchanged water, 6.2 parts of sodium hydroxide (alkali metal hydroxide) is added to 50 parts of ion-exchanged water. The dissolved aqueous solution was gradually added under stirring to prepare a magnesium hydroxide colloid (slightly water-soluble metal hydroxide colloid) dispersion.

The polymerizable monomer composition was charged into the magnesium hydroxide colloid dispersion obtained above at room temperature and stirred. Thereto, 5 parts of t-butylperoxy-2-ethylbutanoate (formula 5) (manufactured by Akzo Nobel, trade name: Trigonox 27) as a polymerization initiator and 1.6 parts of t-dodecyl mercaptan as a molecular weight regulator And 0.7 part of divinylbenzene as a crosslinkable polymerizable monomer, and then using an in-line type emulsifying disperser (manufactured by Taiheiyo Kiko Co., Ltd., trade name: Cavitron) at 15,000 rpm. Dispersion was carried out by high-speed shearing for a minute to form droplets of the polymerizable monomer composition.
0.1 parts of pyrogallol (the following formula 7) was added as a small particle size fine particle inhibitor to the suspension after forming the droplets of the polymerizable monomer composition, and further stirred.

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. 2,2′-azobis which is a polymerization initiator for shell dissolved in 2.1 parts of methyl methacrylate as a polymerizable monomer for shell and 20 parts of ion-exchanged water when the polymerization conversion rate reaches 95%. 0.22 parts of (2-methyl-N- (2-hydroxyethyl) propionamide) (manufactured by Wako Pure Chemical Industries, Ltd., trade name: VA-086, water-soluble) was added, and the reaction was continued at 90 ° C. for 3 hours. Then, the reaction was stopped by cooling with water to obtain an aqueous dispersion of colored resin particles having a core-shell structure.
A part of the aqueous dispersion of the colored resin particles obtained was collected, and the number of small-sized fine particles produced as a by-product was measured.

To the aqueous dispersion of colored resin particles obtained as described above, sulfuric acid was added dropwise with stirring at room temperature, and acid washing was performed until the pH became 6.5 or lower. Subsequently, filtration separation was performed, 500 parts of ion-exchanged water was added to the obtained solid content to make a slurry again, and water washing treatment (washing, filtration, dehydration) was repeated several times. Subsequently, filtration separation was performed, and the obtained solid content was put in a container of a vacuum dryer, and vacuum drying was performed all day and night under conditions of a pressure of 30 torr and a temperature of 50 ° C. to obtain dried colored resin particles.
The colored resin particles obtained by drying had a volume average particle size (Dv) of 6.5 μm, a particle size distribution (Dv / Dp) of 1.13, and an average circularity of 0.978.

  100 parts of the colored resin particles obtained as described above, 0.8 part of silica fine particles hydrophobized (trade name: TG820F), and silica fine particles hydrophobized (trade name, manufactured by Nippon Aerosil Co., Ltd.) : NA50Y) 1.0 part was added, and the mixture was stirred and externally added using a high-speed stirrer (trade name: FM mixer, manufactured by Mitsui Mining Co., Ltd.). Prepared and subjected to testing.

(Example 2)
In Example 1, the toner of Example 2 was prepared in the same manner as in Example 1 except that the type of the small particle size particle inhibitor was changed to hydroxyhydroquinone (formula 8 below), and used for the test.

(Example 3)
A toner of Example 3 was produced in the same manner as in Example 1 except that the type of copper phthalocyanine pigment in Example 1 was changed to the copper phthalocyanine pigment produced in Production Example 2, and subjected to the test.

Example 4
In Example 1, except that the type of the polymerization initiator was changed to t-butyl peroxy-2-ethylhexanoate (formula 6) (trade name: Perbutyl O, manufactured by NOF Corporation). In the same manner as in Example 1, a toner of Example 4 was produced and used for the test.

(Comparative Example 1)
A toner of Comparative Example 1 was produced in the same manner as in Example 1 except that the small particle size fine particle inhibitor was not added in Example 1 and was subjected to the test.

(Comparative Example 2)
In Example 1, the type of copper phthalocyanine pigment was changed to a commercially available copper phthalocyanine pigment having a free copper content of 2470 ppm (trade name: GC-TF, manufactured by Dainippon Ink & Chemicals, Inc.) to suppress small particle size fine particles. A toner of Comparative Example 2 was produced in the same manner as in Example 1 except that the type of the agent was changed to hydroquinone (Formula 9 below), and used for the test.

(result)
Table 1 shows the test results of the toners produced in each Example and Comparative Example.

(Summary of results)
From the test results described in Table 1, the following can be understood.
The toner of Comparative Example 1 is due to the fact that the small particle size fine particle inhibitor was not used, and the toner of Comparative Example 2 was due to the use of a copper phthalocyanine pigment containing free copper in a specific amount or more. The by-product of the fine particles could not be sufficiently suppressed.

  On the other hand, the toners of Examples 1 to 3 were caused by using a specific amount of a copper phthalocyanine pigment in which the content of free copper was reduced to a specific amount or less and a small particle size fine particle inhibitor as a colorant. Thus, the generation of small particle size fine particles by-produced during the polymerization of the toner can be effectively suppressed, and a desired toner is obtained. Further, the toner of Example 4 is more effective in suppressing the generation of small particle size fine particles that are produced as a by-product during polymerization compared to Examples 1 to 3 due to the use of perbutyl O as a polymerization initiator. It was excellent.

Claims (9)

A polymerizable monomer composition containing at least a polymerizable monomer and a colorant is suspended in an aqueous dispersion medium containing a dispersion stabilizer, and droplets of the polymerizable monomer composition are formed. A method for producing a toner for developing an electrostatic image, comprising: a suspension step for obtaining a dispersed suspension; and a step of subjecting the suspension to suspension polymerization in the presence of a polymerization initiator to obtain colored resin particles. ,
The colorant is a copper phthalocyanine pigment having a free copper content of 500 ppm or less,
When the suspension polymerization is performed, the suspension contains 0.01 to 1 part by weight of the small particle size inhibitor with respect to 100 parts by weight of the polymerizable monomer. A method for producing a toner for image development. 2. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the small particle size fine particle inhibitor has a structure represented by the following formula 1, formula 2, or formula 3.

(In the above formulas 1 to 3, R is OX, SO ₃ X, CO ₂ X, or CH═CHCO ₂ X, and X is hydrogen or metal.)   The electrostatic charge image developing toner according to claim 1, wherein the small particle size fine particle inhibitor is added to a suspension after forming a droplet of the polymerizable monomer composition. Production method.   The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the polymerization initiator is an organic peroxide.   The method for producing a toner for developing an electrostatic charge image according to claim 4, wherein the organic peroxide is a peroxyester compound.   6. The method for producing a toner for developing an electrostatic charge image according to claim 5, wherein the peroxyester compound is t-butylperoxy-2-ethylhexanoate.   The method for producing a toner for developing an electrostatic charge image according to any one of claims 1 to 6, wherein an average number of fine particles having a small particle size per one colored resin particle is 100 or less.   The method for producing a toner for developing an electrostatic charge image according to any one of claims 1 to 7, wherein the average circularity of the colored resin particles is 0.96 to 0.995.   The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the toner for developing an electrostatic charge image is a positively chargeable toner.