JP2010049204A - Method for producing toner particle and method for producing toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide toner particles which is excellent in concealment and coloring and improves the quality of an image in an electrophotographic method, an electrostatic recording method and so on; and to provide a method for producing the toner. <P>SOLUTION: The method for producing toner particles includes: a granulating step in which a colorant, a monomer and an aqueous medium are mixed together to obtain a granular substance containing the colorant and the monomer; and a polymerization step in which the monomer contained in the granular substance is polymerized, wherein the colorant includes pigment particles dispersed in a polymer phase and is pigment-composite hollow particles, each of which has at least one pore therein, and the colorant is dispersed in the polymer derived from the monomer to form the toner particles. In addition, the method for producing a toner includes a step in which the toner particles obtained by the method for producing the toner particles and an external additive are mixed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing toner particles that can be used in an electrophotographic apparatus (image forming apparatus) using an electrophotographic process such as a copying machine, a printer, and a facsimile machine.

A method of visualizing image information through an electrostatic latent image, such as electrophotography, is widely used in various fields. In this electrophotographic method, an electrostatic latent image on the surface of an electrophotographic photosensitive member (electrostatic latent image carrier, hereinafter sometimes referred to as “photosensitive member”) is charged into toner particles through a charging step, an exposure step, and the like. The electrostatic latent image is visualized by developing with a toner for developing an electrostatic latent image and further through a transfer process, a fixing process, and the like.
As a method for producing toner particles, a suspension polymerization method and a kneading pulverization method are known. The toner particle manufacturing method by suspension polymerization is a method in which a monomer, a colorant, a release agent, a polymerization initiator and, if necessary, a crosslinking agent, a charge control agent and other additives are uniformly dissolved or dispersed. This is a production method in which the monomer composition is dispersed in an aqueous medium containing a dispersion stabilizer using a suitable stirrer and subjected to a polymerization reaction to form toner particles (for example, , See Patent Document 1).
On the other hand, the kneading and pulverization method has a relatively wide particle size distribution of the obtained toner particles, and the shape thereof is indefinite, so that the performance maintainability is not sufficient.

Japanese Patent Laid-Open No. 2007-127680

  However, since the colorant used in the toner described in Patent Document 1 uses particles made of an inorganic pigment or an organic pigment as they are, the colorability of a fixed image and the like in an electrophotographic method, an electrostatic recording method, etc. Concealment is not enough.

  An object of the present invention is to provide a method for producing toner particles that is excellent in coloring and hiding properties of a fixed image and can improve image quality in electrophotography, electrostatic recording, and the like.

The present invention is as follows.
1. A granulating step of mixing a colorant, a monomer and an aqueous medium to obtain a granulated product containing the colorant and the monomer, and a polymerization for polymerizing the monomer contained in the granulated product The colorant is a pigment-combined hollow particle in which pigment particles are dispersed in a polymer phase and at least one void is formed therein, and the colorant is A method for producing toner particles, comprising producing toner particles dispersed in a polymer derived from a monomer.
2. The number average particle size of the pigment composite hollow particles is 20 nm to 100 μm. 2. A method for producing toner particles according to 1.
3. The content of the pigment particles contained in the pigment composite hollow particles is 3 to 80 parts by mass when the polymer constituting the polymer phase is 100 parts by mass. Or 2. 2. A method for producing toner particles according to 1.
4). The ratio of the total volume occupied by the voids of the pigment composite hollow particles is 5 to 90% by volume when the volume of the entire pigment composite hollow particles is 100% by volume. To 3. The method for producing toner particles according to any one of the above.
5). 1. The granulated product further contains a charge control agent and / or a release agent. To 4. The method for producing toner particles according to any one of the above.
6). In the granulation step, the colorant, the monomer, and the aqueous medium are mixed in the presence of a dispersion stabilizer. To 5. The method for producing toner particles according to any one of the above.
7). 6. The above dispersion stabilizer is hydroxyapatite. 2. A method for producing toner particles according to 1.
8). Above 1. To 7. A method for producing toner, comprising a step of mixing toner particles obtained by the method for producing toner particles according to any one of the above and an external additive.

The method for producing toner particles of the present invention comprises a granulating step of mixing a colorant, a monomer and an aqueous medium to obtain a granulated product containing the colorant and the monomer, and the above granulated product. A polymerization step of polymerizing the monomer contained, and the colorant is a pigment composite in which pigment particles are dispersed in a polymer phase and at least one void is formed therein Since toner particles that are hollow particles and in which the colorant is dispersed in the polymer derived from the monomer are produced, toner particles that are excellent in coloration and concealment of a fixed image are efficiently produced. be able to.
Further, when the content of the pigment particles in the pigment composite hollow particles is 3 to 80% by mass when the total amount of the polymer phase is 100% by mass, the colorability of the fixed image is further increased. In addition, toner particles having excellent concealability can be produced.
Further, when the ratio of the total volume occupied by the voids of the pigment composite hollow particles is 5 to 90% by volume when the volume of the entire pigment composite hollow particles is 100% by volume, the fixing is further performed. Toner particles having excellent image colorability and hiding properties can be produced.
Further, when the dispersion stabilizer is hydroxyapatite, the granulated product produced in the granulation step is finely dispersed, so that toner particles having a narrower particle size distribution can be produced.
Furthermore, since the method for producing a toner of the present invention includes a step of mixing the toner particles and the external additive in the present invention, it is possible to produce a toner that is excellent in coloration and concealment of a fixed image.

  Hereinafter, the present invention will be described in detail. In the present specification, “(meth) acryl” means acryl and methacryl, and “(meth) acrylate” means acrylate and methacrylate.

[1] Method for Producing Toner Particles The present invention comprises a granulation step of mixing a colorant, a monomer, and an aqueous medium to obtain a granulated product containing the colorant and the monomer, and the granulation described above. A polymerization step of polymerizing the monomer contained in the product, wherein the colorant is a pigment in which pigment particles are dispersed in a polymer phase and at least one void is formed therein The toner particles are composite hollow particles, wherein the colorant is dispersed in a polymer derived from the monomer.

  The granulation step is a step of obtaining a granulated product containing the colorant and the monomer by mixing the colorant, the monomer and the aqueous medium. This granulated product is a fine droplet in which the colorant and the monomer are in contact with each other. When a charge control agent and a release agent, which will be described later, are used in the granulation step, these granules are droplets. May be included. The number average particle size of the granulated product is preferably 20 nm to 100 μm, more preferably 30 nm to 80 μm, and still more preferably 40 nm to 70 μm.

In the granulation step, the proportion of the colorant and the monomer used is preferably 100 to 5000 parts by mass, more preferably 200 to 3000 parts by mass with respect to 100 parts by mass of the colorant. More preferably, the content is 300 to 2000 parts by mass. With these content ratios, the colorant can be suitably dispersed in the finally obtained toner particles.
Moreover, the ratio of the usage-amount of a monomer and an aqueous medium is an aqueous medium with respect to 100 mass parts of said monomers, Preferably it is 50-1000 mass parts, More preferably, it is 100-800 mass parts, More preferably, it is. 100 to 600 parts by mass. If it is these content rates, a granulated material can be disperse | distributed suitably in an aqueous medium, and stability is also favorable.

In the granulation step, the method for obtaining the granulated product is not particularly limited, and the colorant, the monomer and the aqueous medium may be mixed together, or a specific one selected from these in advance. After mixing the components, the remainder may be blended and mixed. Specific examples of how to use each component in preparing the granulated product are shown below.
(1) A method of preparing a colorant dispersion by mixing a colorant and an aqueous medium, and then mixing the colorant dispersion and a monomer.
(2) A method of mixing a colorant and a monomer and then mixing the mixture and an aqueous medium.
(3) A first mixture is prepared by mixing the colorant and a part of the monomer, and then the second mixture is prepared by mixing the first mixture and the remaining monomers. . Next, a method of mixing the second mixture and the aqueous medium.
(4) A colorant dispersion is prepared by mixing a colorant and a part of the aqueous medium, while a monomer dispersion is prepared by mixing the monomer and the remainder of the aqueous medium. To do. Thereafter, the colorant dispersion and the monomer dispersion are mixed.
(5) A method of mixing a colorant, a monomer, and an aqueous medium.
Of these, the methods (1) to (3) are preferred. In the above methods (1) to (5), a known charge control agent, release agent, release agent encapsulation promoter, colorant or A monomer dispersion stabilizer, a polymerization initiator, and the like can be used in combination as appropriate.

  In the method for producing toner particles of the present invention, it is preferable to use a dispersion stabilizer in combination in order to obtain a finely dispersed granulated product. Therefore, in the granulation step, it is preferable to mix the colorant, the monomer, and the aqueous medium in the presence of the dispersion stabilizer.

In the method of (1) above, when preparing a colorant dispersion using a colorant and an aqueous medium, the aqueous medium may be used as it is or after blending a dispersion stabilizer in the aqueous medium. . The method of using the colorant and the aqueous medium is not particularly limited. Usually, the colorant is added to the aqueous medium in a lump, divided or continuously while stirring the aqueous medium, and both are mixed. As a result, a colorant dispersion is obtained.
Thereafter, the colorant dispersion and the monomer are mixed to prepare a granulated product, and both may be mixed together, either one is divided or continuously added to the other, You may mix.

In the method of (2) above, when preparing a mixture using a colorant and a monomer, the method of using these is not particularly limited, but usually the colorant is batched under stirring of the monomer. Add to this monomer in portions or continuously and mix them. As a result, the above mixture is obtained.
Thereafter, the mixture and the aqueous medium are mixed to prepare a granulated product, which may be mixed together, or one of them may be divided or continuously added to the other and mixed. Good.

In the method (3), when the first mixture is prepared using a part of the colorant and the monomer, the ratio of the colorant to the monomer is not particularly limited, but the colorant 100 mass. The amount of the monomer is usually preferably 50 to 2000 parts by mass, more preferably 100 to 1500 parts by mass, and still more preferably 150 to 1000 parts by mass with respect to parts. It can be set as the 1st mixture in which the coloring agent was suitably disperse | distributed as it is the said ratio.
In addition, the monomer used for preparation of this 1st mixture may be a mixture with a polymerization initiator.
Next, the first mixture and the remaining monomers are mixed to prepare a second mixture, and then the second mixture and the aqueous medium are mixed to prepare a granulated product. May be mixed, or one of them may be divided or continuously added to the other and mixed.

By the methods (1) to (5) above, a granulated product that is uniformly dispersed in the aqueous medium can be formed. And when all of a coloring agent, a monomer, and an aqueous medium existed, a granulated material can be manufactured more efficiently by taking a stirring means having a high shearing force. Examples of the stirring means having a high shearing force include a high-pressure disperser. A known high-pressure disperser can be used. For example, edged turbine blades, ultra turrax (manufactured by IKA), T.W. K. A high-speed stirrer such as a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) or Claremix (manufactured by M Technique Corp.) can be used.
In the granulated product obtained as described above, the colorant and the monomer are in contact with each other, become fine droplets, and are dispersed in the aqueous medium.

Hereinafter, the component used for formation of a granulated material is demonstrated.
The monomer is not particularly limited, but is preferably a vinyl monomer having hydrophobicity and capable of radical polymerization. Examples of vinyl monomers include monofunctional monomers and polyfunctional monomers.
Examples of the monofunctional monomer include styrene, α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, and pn-butylstyrene. , P-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p- Styrene derivatives such as phenylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, (meth ) Iso-butyl acrylate, tert-butyl (meth) acrylate, n-amyl (meth) acrylate, (meth) acrylic acid N-hexyl acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, n-nonyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, (meth) (Meth) acrylic monomers such as dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl (meth) acrylate, dibutyl phosphate ethyl (meth) acrylate, 2-benzoyloxyethyl (meth) acrylate; methylene fat Vinyl esters such as vinyl monoesters, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, vinyl formate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether; vinyl methyl ketone, vinyl hexyl ketone, Vinyl Vinyl ketones such as methyl ketone.

  Examples of the polyfunctional monomer include diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,6-hexanediol di (Meth) acrylate, neopentyl glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 2,2′-bis (4-((meth) acryloxydiethoxy) phenyl ) Propane, trimethylolpropane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, ethylene glycol di (meth) acrylate, divinylbenzene, divinylnaphthalene, divinylacetate Le and the like.

  In the present invention, the above monofunctional monomers are used alone or in combination of two or more, or the above monofunctional monomers and polyfunctional monomers are combined, or a polyfunctional monomer. The body can be used alone or in combination of two or more. Among the above monomers, styrene or a styrene derivative may be used alone or in combination, or mixed with other monomers and used from the viewpoints of toner development characteristics and durability. .

  The colorant is a pigment-complexed hollow particle (hereinafter sometimes referred to as “hollow particle”) in which pigment particles are dispersed in a polymer phase and at least one void is formed therein.

The polymer constituting the polymer phase is preferably a structural unit derived from a polymerizable crosslinkable monomer (hereinafter referred to as “structural unit (a)”), and a water-soluble polymer having a polymerizable property. It is a polymer containing a structural unit derived from a monomer (hereinafter referred to as “structural unit (b)”) and, if necessary, referred to as another structural unit (hereinafter referred to as “structural unit (c)”). ) May further be contained. By containing the structural units (a) and (b), the strength of the polymer phase is improved, and cracking and crushing of the hollow particles can be suppressed.
Moreover, by containing the said structural unit (a), abrasion resistance is good, it is hard to be crushed, and it is excellent in durability. Thus, since it is excellent in durability, the space | gap in a hollow particle becomes difficult to be crushed.
Furthermore, by containing the structural unit (b), the dispersibility and stability of the pigment particles in the hollow particles are excellent.

  The polymerizable crosslinkable monomer (hereinafter also referred to as “crosslinkable monomer”) forming the structural unit (a) is preferably a polyfunctional unsaturated compound such as divinylbenzene, Trivinylbenzene, ethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, allyl (meth) acrylate, ethylenedi ( Examples include (meth) acrylate, diethylene di (meth) acrylate, triethylene di (meth) acrylate, propylene di (meth) acrylate, dipropylene di (meth) acrylate, diallyl phthalate, triallyl cyanurate, and the like. These compounds can be used alone or in combination of two or more. Of these, divirbenzene, ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate are preferred. The structural unit (a) formed by using divirbenzene, ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate shortens the molecular weight between crosslinking points and improves the crosslinking density.

  The content of the structural unit (a) constituting the polymer is preferably 3 to 70% by mass, and 5 to 60% by mass when the total structural unit in the polymer is 100% by mass. More preferably, it is more preferably 7 to 50% by mass. Since the intensity | strength of a hollow particle improves that the said content rate exists in the said range, the crack and crushing of particle | grains can be suppressed.

  As the water-soluble monomer having a polymerizable property for forming the structural unit (b), (meth) having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate Acrylic acid ester compound; (meth) acrylic acid ester compound having amino group such as (meth) acrylic acid 2-dimethylaminoethyl, (meth) acrylic acid 2-diethylaminoethyl; (meth) acrylamide, N-methylol (meth) Unsaturated amide compounds such as acrylamide; unsaturated acids such as acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid and cinnamic acid; vinyl ester compounds such as vinyl formate and vinyl acetate; styrene sulfone Examples include acid salts (Na salts). These compounds can be used alone or in combination of two or more.

  The content of the structural unit (b) constituting the polymer is preferably 0.5 to 15.0% by mass when the total structural unit in the polymer is 100% by mass. More preferably, it is 5-13 mass%, and it is still more preferable that it is 0.5-10 mass%. When the said content rate is 0.5-15.0 mass%, the dispersibility and stability of the pigment particle contained in a polymer phase are excellent.

  As described above, the polymer can further contain a structural unit (c) in addition to the structural unit (a) and the structural unit (b). This structural unit (c) is usually a polymerizable crosslinkable monomer and a monomer copolymerizable with a polymerizable water-soluble monomer (hereinafter referred to as “other monomer”). )).

  The other monomer is preferably a monomer having radical polymerizability. For example, aromatic vinyl compound, (meth) acrylic acid alkyl ester compound, alkoxyl group, (meth) acrylic acid ester compound having functional group such as cyano group, vinyl cyanide compound, conjugated diene compound, non-conjugated diene compound, epoxy And group-containing unsaturated compounds.

  Examples of the aromatic vinyl compound include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-tert-butylstyrene, Examples thereof include tert-butoxystyrene, vinyl toluene, vinyl naphthalene, and vinyl pyridine.

  Examples of the (meth) acrylic acid alkyl ester compound include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, Isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-pentyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, (Meth) acrylic acid 2-methylpentyl, (meth) acrylic acid n-octyl, (meth) acrylic acid 2-ethylhexyl, (meth) acrylic acid n-decyl, (meth) acrylic acid n-dodecyl, (meth) acrylic N-octadecyl acid, cyclohexyl (meth) acrylate, phenyl (meth) acrylate, (meth) Benzyl acrylic acid and the like.

  Examples of the (meth) acrylic acid ester compound having an alkoxyl group include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2- (n-propoxy) ethyl (meth) acrylate, (meth ) 2- (n-butoxy) ethyl acrylate, 3-methoxypropyl (meth) acrylate, 3-ethoxypropyl (meth) acrylate, 2- (n-propoxy) propyl (meth) acrylate, (meth) acryl Examples include acid 2- (n-butoxy) propyl.

  Examples of the (meth) acrylic acid ester compound having a cyano group include cyanomethyl (meth) acrylate, 1-cyanoethyl (meth) acrylate, 2-cyanoethyl (meth) acrylate, 1-cyanopropyl (meth) acrylate, ( 2-cyanopropyl (meth) acrylate, 3-cyanopropyl (meth) acrylate, 4-cyanobutyl (meth) acrylate, 6-cyanohexyl (meth) acrylate, 2-ethyl-6-cyano (meth) acrylate Examples include hexyl and 8-cyanooctyl (meth) acrylate.

Examples of the vinyl cyanide compound include acrylonitrile, methacrylonitrile, ethacrylonitrile and the like.
Examples of the conjugated diene compound include butadiene, isoprene, chloroprene and the like.
Examples of the non-conjugated diene compound include 1,4-hexadiene and dicyclopentadiene.
Examples of the epoxy group-containing unsaturated compound include glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, β-ethylglycidyl (meth) acrylate, and 3-methyl-3,4-epoxy (meth) acrylate. Butyl, 3-ethyl-3,4-epoxybutyl (meth) acrylate, 4-methyl-4,5-epoxypentyl (meth) acrylate, 2,3-epoxycyclohexylmethyl (meth) acrylate, (meth) 3,4-epoxycyclohexylmethyl acrylate, o-vinylbenzylglycidyl ether, m-vinylbenzylglycidyl ether, p-vinylbenzylglycidyl ether, 2-vinylcyclohexene oxide, 3-vinylcyclohexene oxide, 4-vinylcyclohexene oxide, allyl Glycidyl ether Etc.
Other vinyl ester compounds such as vinyl propionate; halogen-containing unsaturated compounds such as vinyl chloride and vinylidene chloride; maleimide compounds such as maleimide, N-methylmaleimide, N-butylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide Styrenesulfonic acid, α-methylstyrenesulfonic acid; 3-acryloxy-2-hydroxypropanesulfonic acid, 3-methacryloxy-2-hydroxypropanesulfonic acid, 3-acryloxy-1-hydroxypropane-2-sulfonic acid, 3- Methacryloxy-1-hydroxypropane-2-sulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, 2-hydroxy-3-butenesulfonic acid, vinylsulfonic acid, allylsulfonic acid, methallylsulfonic acid, vinylphenol Methane sulfonic acid, iso-amylene sulfonic acids, such as 2-methyl-1,3-butadiene-1-sulfonic acid.

  The content of the structural unit (c) is preferably 15.0 to 96.5% by mass, when the total structural unit in the polymer is 100% by mass, and is preferably 15 to 94.5% by mass. Is more preferable, and it is still more preferable that it is 15-92.5 mass%. When the content is 15.0 to 96.5% by mass, the porosity is excellent.

  Among the above monomers, a more preferable combination of the monomers that form the polymer phase of the hollow particles in the present invention is that the monomer that forms the structural unit (a) is divinylbenzene, and the structural unit (b) Is a unsaturated acid, and the monomer forming the structural unit (c) is an aromatic vinyl compound and / or a (meth) acrylic acid alkyl ester compound. With these combinations, the strength of the hollow particles is improved and the dispersibility in the toner is excellent.

  The pigment particles are particles made of a colored compound that does not dissolve in water and an organic solvent. This colored compound may be either an organic compound (organic pigment) or an inorganic compound (inorganic pigment). Organic pigments include insoluble azo pigments, condensed azo pigments, azo lakes, chelate azo pigments, etc .; phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments And polycyclic pigments such as dye lakes, nitro pigments, nitroso pigments, aniline black, and fluorescent pigments. Of these, azo pigments, phthalocyanine pigments, and polycyclic pigments are preferred. Examples of inorganic pigments include titanium oxide, carbon black, red pepper, cadmium red, molybdenum orange, yellow iron oxide, yellow lead, titanium yellow, chrome green, chromium oxide, cobalt blue, and manganese violet.

  The number average particle diameter of the pigment particles is preferably 1 nm to 1 μm, more preferably 1 nm to 500 nm, still more preferably 5 nm to 50 nm. When the number average particle diameter of the pigment particles is in the above range, the dispersibility in the polymer phase is excellent.

  The content of the pigment particles in the hollow particles is preferably 3 to 80 parts by mass, more preferably 4 to 75 parts by mass, and more preferably 5 to 70, when the polymer constituting the polymer phase is 100 parts by mass. Part by mass is more preferable. When the content of the pigment particles is in the above range, the color developability as a colorant is excellent.

  The hollow particles are composite particles having an outer wall (shell) containing the polymer and the pigment particles, and having at least one void therein. The pigment particles are uniformly dispersed in the polymer phase, and the composite particles themselves are granular bodies reflecting the color of the pigment particles.

The shape of the voids in the hollow particles is not particularly limited, and may be a sphere, an elliptic sphere, a polyhedron, a linear body, a curved body, a combination or a deformed body thereof, or the like. Accordingly, the inner wall surface facing the gap can also have various forms, such as a smooth flat surface, a curved surface, and an uneven surface.
The number of voids in the hollow particles may be one or plural. Furthermore, when a plurality of voids are formed, they may be continuous.
The form of the said hollow particle is illustrated below.
(1) Hollow particles having only one void.
(2) Hollow particles having a plurality of voids and isolated from each other.
(3) Hollow particles having a plurality of voids and communicating with each other through a linear space or the like.
Examples of the aspect (3) include hollow particles having communication holes such as a three-dimensional network inside.

In the colorant (pigment composite hollow particles), the ratio of the total volume of all voids, that is, the void ratio is 5 to 5% when the volume of the entire hollow particles (the outer shape of the hollow particles) is 100% by volume. It is preferably 90% by volume, more preferably 5 to 70% by volume, and still more preferably 6 to 60% by volume. When the porosity is in the above range, the mechanical strength is excellent.
In the present specification, the porosity is arbitrarily selected from 10 particles observed by a transmission electron microscope (“H-7650”, manufactured by Hitachi High-Technology Co., Ltd.). Is a value calculated by
[(Total volume of the void) / {4 [pi] (outer diameter ^{/ 2} of the hollow particles) 3/3}] × 100 (1)
In addition, when there is only one void and the shape is a spherical body, the void ratio can be calculated by the following formula (2).
{(Inner diameter of void) ³ / (Outer diameter of hollow particle) ³ } × 100 (2)

  The outer shape of the hollow particles is not particularly limited, and may be a sphere, an elliptic sphere, a polyhedron, or a deformed body thereof. Moreover, the surface of the said colorant is not specifically limited, It can be set as a smooth curved surface, an uneven surface, etc.

  The number average particle diameter of the hollow particles is preferably 20 nm to 100 μm, more preferably 30 nm to 50 μm, and still more preferably 50 nm to 10 μm.

  The surface layer portion of the outer wall of the hollow particles preferably has a structural unit (a), and further preferably has a structural unit (c). By having these structural units in the surface layer portion, the durability and the dispersibility in the polymer phase are excellent.

The colorant has a polymer phase containing the pigment particles, and at least one space filled with gas is formed. By forming this space, the light incident on the hollow particles is scattered on the surface of the hollow particles and the inner wall forming the space. Therefore, the toner particles obtained according to the present invention using the colorant are excellent in hiding properties.
The method for producing the colorant will be described later.

  As described above, the granulated product obtained by the granulation step may contain a charge control agent, a release agent, and the like as necessary. The charge control agent can be externally added to the toner particles, but is preferably contained in the granulated material and then contained in the toner particles.

  In the above charge control agent, for controlling toner particles to be negatively charged, for example, organometallic compounds and chelate compounds are effective, and monoazo dye metal compounds, acetylacetone metal compounds, aromatic hydroxycarboxylic acids, aromatic compounds Mono and polycarboxylic acids and their metal salts, anhydrides, esters, phenol derivatives such as bisphenol, and the like. These can be used alone or in combination of two or more.

  The toner particles are controlled to be positively charged, such as modified products of nigrosine and fatty acid metal salts, quaternary compounds such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate and the like. Ammonium salts and onium salts such as phosphonium salts thereof and their lake pigments, triphenylmethane dyes and their lake pigments (as rake agents, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid Tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.), metal salts of higher fatty acids, diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide, dibutyltin volley , Dioctyl tin borate, may diorgano tin borate, and the like, such as dicyclohexyl tin borate, and these can be used singly or in combination of two or more. Among these, a charge control agent such as nigrosine and quaternary ammonium salt is particularly preferably used.

  These charge control agents are preferably used in an amount of 0.01 to 20 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the monomer.

  As the release agent, a wax that is in a solid state at room temperature and usually used as a lubricant is preferable in terms of toner blocking resistance, durability of a large number of sheets, low-temperature fixability, and offset resistance. Moreover, the mixing | blending time of a mold release agent is not specifically limited.

  Examples of the release agent include polymethylene wax such as paraffin wax, polyolefin wax, microcrystalline wax, and Fischer-Tropsch wax, linear alkyl alcohol having 15 to 100 carbon atoms, linear fatty acid, and linear acid amide. And waxes of linear esters or montan derivatives and derivatives such as graft compounds and block compounds thereof. These are preferably removed from the low molecular weight component and have a sharp maximum endothermic peak in the endothermic curve obtained by a differential scanning calorimeter. These can be used alone or in combination of two or more.

  These release agents are preferably used in an amount of 1 to 40 parts by weight, more preferably 4 to 30 parts by weight, based on 100 parts by weight of the polymerizable monomer.

  Moreover, when using a mold release agent, promotion of inclusion of a mold release agent can be aimed at by adding polar resin. When a polar resin is present in a granulated product suspended in an aqueous medium, the polar resin tends to migrate to the vicinity of the interface between the aqueous medium and the granulated product due to the difference in affinity for water. Polar resin will be unevenly distributed. As a result, the toner particles have a core-shell structure, and the inclusion property of the release agent is improved even when a large amount of the release agent is contained.

  In addition, if a resin with a high melting temperature is selected as the polar resin used for the shell, even if the binder resin is designed to be melted at a lower temperature for the purpose of fixing at low temperature, it may cause problems such as blocking during storage. Can be suppressed.

  As such a polar resin, a polyester-based resin is preferable since the fluidity of the polar resin itself can be expected when the shell is formed unevenly distributed on the surface of the toner particles.

  The polyester-based resin is not particularly limited as long as it has an ester bond in the main chain of the molecule, and may be a saturated polyester resin or an unsaturated polyester resin. Moreover, these can also be used in combination. Furthermore, the polyester resin may be a crystalline resin or an amorphous resin. As the polyester resin, a resin obtained by condensation polymerization of an acid component monomer and an alcohol component monomer can be used.

  The above acid component monomers include terephthalic acid, isophthalic acid, phthalic acid, fumaric acid, maleic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, ginger Examples include oxalic acid, cyclohexanedicarboxylic acid, trimellitic acid, and the like. These can be used alone or in combination of two or more.

  Examples of the alcohol component monomer include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-bis (hydroxy Examples include alkylene glycols such as methyl) cyclohexane and polyalkylene glycols, bisphenol A, hydrogenated bisphenol, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, glycerin, trimethylolpropane, pentaerythritol, and the like. These can be used alone or in combination of two or more. Of these, bisphenol A ethylene oxide adduct and bisphenol A propylene oxide adduct are preferred.

  The dispersion stabilizer is preferably a colorant dispersion, a monomer dispersion, a colorant or colorant dispersion, and a monomer or monomer dispersion. Used when mixing. The dispersion stabilizer is not particularly limited as long as the colorant and the monomer are well dispersed in the aqueous medium, and may be a single substance or a mixture of two or more substances. May be. In the latter case, a liquid composition dissolved or dispersed in an aqueous medium can be used.

The constituent component of the dispersion stabilizer may be either an inorganic compound or an organic compound, or a combination thereof.
Inorganic compounds include tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, Examples include bentonite, silica, alumina, titania, and hydroxyapatite.
Examples of the organic compound include polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, starch and the like. These can be used alone or in combination of two or more.

In addition, when preparing a dispersion stabilizer containing an inorganic compound, for example, a dispersion stabilizer containing tricalcium phosphate can be prepared by sufficiently stirring an aqueous sodium phosphate solution and an aqueous calcium chloride solution. When a stabilizer is used, a finely dispersed granulated product can be obtained efficiently.
The amount of the dispersion stabilizer (pure component excluding the medium) is preferably 0.2 to 10.0 parts by mass with respect to 100 parts by mass of the monomer.

  Examples of the polymerization initiator include an azo polymerization initiator, an organic peroxide initiator, and a redox initiator in which an oxidizing substance and a reducing substance are combined. These can be used alone or in combination of two or more.

  Examples of the azo polymerization initiator include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbohydrate). Nitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobismethylbutyronitrile and the like.

  Examples of the organic peroxide initiator include benzoyl peroxide, lauroyl peroxide, di-α-cumyl peroxide, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, bis (4-t- Butylcyclohexyl) peroxydicarbonate, 1,1-bis (t-butylperoxy) cyclododecane, t-butylperoxymaleic acid, bis (t-butylperoxy) isophthalate, methyl ethyl ketone peroxide, tert-butylperoxide Examples thereof include oxy-2-ethylhexanoate, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide and the like.

  Examples of the oxidizing substance constituting the redox initiator include inorganic peroxides such as hydrogen peroxide and persulfates (sodium salts, potassium salts, ammonium salts, etc.), and oxidizing metal salts such as tetravalent cerium salts. Etc. The reducing substance constituting the redox initiator includes reducing metal salts (divalent iron salts, monovalent copper salts, trivalent chromium salts, etc.), ammonia, lower amines (methylamine, ethylamine, etc.). Amines having about 1 to 6 carbon atoms), amino compounds such as hydroxylamine, reducing sulfur compounds such as sodium thiosulfate, sodium hydrosulfite, sodium hydrogen sulfite, sodium sulfite, sodium formaldehyde sulfoxylate, lower alcohols (carbon Number 1 to 6), ascorbic acid or a salt thereof, and a lower aldehyde (about 1 to 6 carbon atoms).

  The above polymerization initiator is selected with reference to the 10-hour half-life temperature, and can be used alone or in combination of two or more. Although the addition amount of the polymerization initiator varies depending on the target degree of polymerization, it is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the monomer. More preferably, it is 1 to 5 parts by mass. When the addition amount of the polymerization initiator is within the above range, the monomer is favorably polymerized.

Next, in the polymerization step, in the polymer in which the monomer contained in the granulated product obtained by the granulation step is polymerized, and the colorant contained in the granulated product is formed from the monomer. Toner particles dispersed in are produced.
When the granulated product obtained by the granulation step contains a polymerization initiator, it is not necessary to add a new polymerization initiator in this polymerization step, but the granulated product contains a polymerization initiator. When not included, a polymerization initiator is blended in the reaction system. The amount used is as described above.

  The polymerization temperature is preferably 40 ° C to 95 ° C, more preferably 50 ° C to 90 ° C, still more preferably 60 ° C to 80 ° C. When the polymerization temperature is within the above range, the monomer is favorably polymerized. The polymerization temperature may be constant throughout, but may be raised in the latter half of the polymerization step for the purpose of obtaining a desired molecular weight distribution.

  After the polymerization step, when volatile impurities such as unreacted monomers and by-products are contained in the reaction system, distillation may be performed to remove them. Distillation can be performed under normal pressure or reduced pressure.

  Further, when a dispersion stabilizer is used in the granulation step, the dispersion stabilizer may adhere to the surface of the obtained toner particles depending on the type. In that case, the dispersion of the toner particles can be treated with an acid or an alkali in order to remove the attached dispersion stabilizer. Thereafter, the toner particles are separated from the liquid phase by a solid-liquid separation method, but in order to completely remove the acid or alkali and the dispersion stabilizer dissolved therein, water is again added to wash the toner particles. This process is repeated several times, and after sufficient washing, solid-liquid separation is performed again to obtain toner particles. The obtained toner particles are dried by a known drying means if necessary.

The number average particle diameter of the toner particles obtained by the present invention is preferably 30 nm to 150 μm, more preferably 50 nm to 80 μm, and still more preferably 80 nm to 70 μm. The number variation coefficient (%) of the toner particles obtained by the toner particle production method of the present invention by the following calculation method is preferably 15 to 40%, more preferably 15 to 37%, and still more preferably. 15-35%.
Number variation coefficient (%) = number standard deviation ÷ number average diameter × 100

  The method for producing the colorant is not particularly limited, but the polymer constituting the polymer phase is a water-soluble polymer having a structural unit (a) derived from a polymerizable crosslinkable monomer and a polymerizable polymer. Since it contains the structural unit (b) derived from the monomer, it is produced using at least these monomers.

  A preferred method for producing the colorant is a step of preparing an aqueous dispersion containing pigment particles, a monomer component (i) mainly containing a non-crosslinkable hydrophobic monomer, and a dispersion medium containing water. (Hereinafter referred to as “first step”), a step of polymerizing the monomer component (i) contained in this aqueous dispersion in the presence of a polymerization initiator to produce an emulsion containing seed polymer particles (hereinafter referred to as “ 2nd step) and a monomer component (ii) containing a crosslinkable monomer having a polymerizable property and a water-soluble monomer having a polymerizable property is added to the emulsion, followed by polymerization. In this method, a step of polymerizing the monomer component (ii) in the presence of an initiator (hereinafter referred to as “third step”) is sequentially provided. According to this method, in the third step, the polymerization of the monomer component (ii) proceeds in a state where the crosslinkable monomer is absorbed by the seed polymer particles, and the monomer component is formed on the surface of the seed polymer particles. A polymer layer containing the structural unit derived from (ii) is formed. At that time, the seed polymer particles shrink with the polymerization of the crosslinkable monomer, and voids are formed inside.

  In the first step, pigment particles, the monomer component (i), an aqueous medium containing water, and other raw material components as necessary are used.

  The monomer component (i) used in the first step is mainly non-crosslinkable hydrophobic monomer, that is, preferably when the monomer component (i) is 100% by mass. The hydrophobic monomer is contained in an amount of 50% by mass or more. As this hydrophobic monomer, “other monomer” that forms another structural unit (c) constituting the polymer phase is usually applied, and an aromatic vinyl compound, (meth) acrylic acid alkyl ester is used. A compound, a (meth) acrylic acid ester compound having a functional group such as an alkoxyl group, a cyano group, a vinyl cyanide compound, a conjugated diene compound, a non-conjugated diene compound, an epoxy group-containing unsaturated compound, or the like can be used. These may be used alone or in combination of two or more.

The monomer component (i) may contain a water-soluble monomer having polymerizability, if necessary.
As the water-soluble monomer, a “water-soluble monomer” that forms the structural unit (b) constituting the polymer phase can be applied.
The content of the water-soluble monomer is preferably 50% by mass or less, and more preferably 30% by mass or less, when the monomer component (i) is 100% by mass.
When the monomer component (i) used in the first step has the above structure, the hollow particles can be efficiently formed.

  The amount of the monomer component (i) used is preferably 5 to 100 parts by mass, more preferably 5 to 70 parts by mass, and still more preferably 5 to 50 parts by mass, when the dispersion medium is 100 parts by mass. It is. When the amount used is above, the monomer component (i) can be emulsified and dispersed in the aqueous dispersion medium with good stability.

In the first step, preferably, before the step of dispersing the pigment particles and the monomer component (i) in the aqueous medium, the preliminary preparation for dispersing the pigment particles in a part or all of the monomer component (i). A dispersion process is performed. By this preliminary dispersion step, the pigment particles are refined and the pigment particles are more uniformly dispersed in the monomer component (i), so that the intended granulated product can be easily obtained. The dispersing device used at this time is not particularly limited, but a ball mill, sand mill, attritor, roll mill, agitator, Henschel mixer, colloid mill, ultrasonic homogenizer, pearl mill, wet jet mill, paint shaker, high pressure homogenizer (microfluidizer, nanomizer, etc.) Etc.) are preferred.
In the preliminary dispersion step, a dispersant can be used. Examples of the dispersant include solvent-based dispersants such as acrylic copolymers, polycarboxylic acids, ethyl cellulose, and polyallylamine-based dispersants.
The amount of the dispersant used is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 15 parts by mass, and still more preferably 0.3 to 10 parts by mass with respect to 100 parts by mass of the pigment particles. is there.

In the step of dispersing the pigment particle and monomer mixture in the first step in an aqueous medium, a dispersant, an emulsifier, or the like can be used.
Examples of the dispersant include water-soluble dispersants such as higher fatty acid salts, polycarboxylic acids, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, and polyethylene glycol.
The amount of the dispersant used is preferably 0.1 to 40 parts by weight, more preferably 0.3 to 35 parts by weight, and still more preferably 0.3 to 30 parts by weight with respect to 100 parts by weight of the pigment particles. is there.

As an emulsifier, an anionic surfactant, a nonionic surfactant, and an amphoteric surfactant can be used. These may be used alone or in combination.
Examples of the anionic surfactant include sulfates of higher alcohols, alkylbenzene sulfonates, aliphatic sulfonates, and sulfates of polyethylene glycol alkyl ethers.
Examples of nonionic surfactants include polyethylene glycol alkyl esters, alkyl ethers, and alkylphenyl ethers.
Amphoteric surfactants include compounds having a carboxylate, sulfate, sulfonate, or phosphate ester salt as the anion moiety and an amine salt or quaternary ammonium salt as the cation moiety, such as lauryl betaine, Examples include betaine type compounds such as stearyl betaine; amino acid type compounds such as lauryl-β-alanine, stearyl-β-alanine, lauryl di (aminoethyl) glycine, and octyldi (aminoethyl) glycine.
The amount of the emulsifier is preferably 0.1 to 30 parts by mass, more preferably 0.2 to 25 parts by mass, and still more preferably 0.3 to 100 parts by mass with respect to 100 parts by mass of the monomer component (i). 20 parts by mass.

The aqueous dispersion may further contain a polymerization initiator, a chain transfer agent, an organic solvent, and the like.
The polymerization initiator is preferably an oil-soluble polymerization initiator, such as cumyl peroxide, tert-butyl peroxide, propionyl peroxide, benzoyl peroxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromomethylbenzoyl peroxide, Lauroyl oxide, diisopropyl peroxycarbonate, 1-phenyl-2-methylpropyl-1-hydroperoxide, pertriphenylacetic acid-tert-butyl hydroperoxide, tert-butyl performate, tert-butyl peracetate, tert-perbenzoic acid -Peroxides such as butyl, tert-butyl perphenyl acetate, tert-butyl permethoxyacetate, tert-butyl per-N- (3-toluyl) palmitate, di (3,5,5-trimethylhexanoyl) peroxide 2,2′-azobispropane, 2,2 '-Dichloro-2,2'-azobispropane, 2,2'-azobisisobutane, 2,2'-azobisisobutylamine, 2,2'-azobisisobutyronitrile, 2,2'-azobis Methyl 2-methylpropionate, 2,2′-dichloro-2,2′-azobisbutane, 2,2′-azobis-2-methylbutyronitrile, dimethyl 2,2′-azobisisobutyrate, 1,1′- Azobis (sodium 1-methylbutyronitrile-3-sulfonate), 2- (4-methylphenylazo) -2-methylmalonodinitrile, 3,5-dihydroxymethylphenylazo-2-methylmalonodinitrile, 2 -(4-Bromophenylazo) -2-allylmalonodinitrile, 2,2'-azobis-2-methylvaleronitrile, dimethyl 4,4'-azobis-4-cyanovalerate, 2,2 '-Azobis-2,4-dimethylvaleronitrile, 1,1'-azobiscyclohexanenitrile, 2,2'-azobis-2-propylbutyronitrile, 1,1'-azobis-1-chlorophenylethane, 1, 1′-azobis-1-cyclohexanecarbonitrile, 1,1′-azobiscyclohexanenitrile, 2,2′-azobis-2-propylbutyronitrile, 1,1′-azobis-1-chlorophenylethane, 1,1 '-Azobis-1-cyclohexanecarbonitrile, 1,1'-azobis-1-cycloheptanecarbonitrile, 1,1'-azobis-1-phenylethane, 1,1'-azobiscumene, 4-nitrophenylazobenzylcyano Ethyl acetate, phenylazodiphenylmethane, phenylazotriphenylmethane, 4-nitrophenylazotri Phenylmethane, 1,1′-azobis-1,2-diphenylethane, poly (bisphenol A-4,4′-azobis-4-cyanopentanoate), poly (tetraethylene glycol-2,2′-azobisiso Butyrate) and the like.
The amount of the polymerization initiator used is preferably 0.1 to 3.0 parts by weight, more preferably 0.2 to 2.5 parts by weight, and more preferably 100 parts by weight of the monomer component (i). Preferably it is 0.3-2.0 mass parts.

Examples of the chain transfer agent include mercaptan compounds such as tert-dodecyl mercaptan, octyl mercaptan, n-tetradecyl mercaptan, and tert-hexyl mercaptan; halogen compounds such as ethylene bromide. When this chain transfer agent is used, the molecular weight of the seed polymerized particles obtained in the second step can be reduced, and the monomer component (iii) used in the third step can be easily absorbed by the seed polymerized particles. Can do.
When the chain transfer agent is used, the amount used is preferably 0.1 to 10 parts by mass, more preferably 0.2 to 7 parts by mass, more preferably 100 parts by mass of the monomer component (i). Preferably it is 0.3-5 mass parts.

  The polymerization initiator and the chain transfer agent may be used as raw materials for preparing the aqueous dispersion, or may be used during the polymerization of the monomer component (i) in the second step.

The organic solvent is preferably a hydrophobic compound, and examples thereof include toluene, xylene, methyl chlorobenzene, methyl ethyl ketone, methyl isobutyl ketone, N-methyl-2-pyrrolidone, and ethylene glycol mono n-butyl ether.
When using the said organic solvent, the usage-amount is with respect to 100 mass parts of said pigment particles, Preferably it is 10-400 mass parts, More preferably, it is 10-300 mass parts, More preferably, it is 15-200 mass parts.

The method for preparing the aqueous dispersion is not particularly limited, but a ball mill, sand mill, attritor, roll mill, agitator, Henschel mixer, colloid mill, ultrasonic homogenizer, pearl mill, wet jet mill, paint shaker, high pressure homogenizer (microfluidizer) It is preferable to use a mixing device such as a nanomizer. Among these apparatuses, a high-pressure homogenizer is preferable because a strong shearing force is applied to reduce the aggregation unit of pigment particles and a dispersion having excellent dispersibility can be prepared. When this high-pressure homogenizer is used, the preferable shearing force is 40 MPa or more, more preferably 50 MPa or more.
In preparation of the aqueous dispersion, the aqueous medium and all other raw material components may be mixed together, or the raw material components other than the aqueous medium may be divided to prepare a plurality of aqueous dispersions. Alternatively, a part of the aqueous medium and a part of other raw material components may be mixed to prepare a plurality of aqueous dispersions, and these aqueous dispersions may be mixed together.

  In the aqueous dispersion obtained as described above, the pigment particles and the monomer component (i) are preferably in contact with each other and dispersed as fine droplets. Further, when an oil-soluble polymerization initiator and a hydrophobic organic solvent are used as raw material components, these are also in contact with the pigment particles and the monomer component (i) and become fine droplets. Are preferably dispersed.

The second step is a step of producing an emulsion containing seed polymer particles by polymerizing the monomer component (i) contained in the aqueous dispersion in the presence of a polymerization initiator.
In the second step, the monomer component (i) is usually polymerized while stirring the aqueous dispersion. As a result, a composite particle in which pigment particles are dispersed in a polymer formed by the monomer component (i) in a dispersion medium containing water, that is, an emulsion containing seed polymer particles is obtained. The polymerization temperature is selected depending on the kind of the polymerization initiator, but is usually 20 ° C to 90 ° C, preferably 30 ° C to 85 ° C. The polymerization time is usually 1 to 12 hours, preferably 3 to 10 hours.

The seed polymer particles are granular bodies having a shape such as a sphere, an elliptic sphere, a polyhedron, or a deformed body thereof, and the number average particle diameter thereof is preferably 10 nm to 99 μm, more preferably 30 nm to 50 μm, and further Preferably it is 50 nm-10 micrometers. If the number average particle diameter is too large, the hollow (space part) in the finally obtained colorant for toner may not be stably formed.
Moreover, the weight average molecular weight of the polymer contained in the seed polymer particles is preferably 100,000 or less, more preferably 50,000 or less, and still more preferably 10,000 or less. If this weight average molecular weight is too large, the hollow (space part) in the finally obtained colorant for toner may not be stably formed.

  Next, in the third step, a monomer component (ii) containing a polymerizable crosslinkable monomer and a polymerizable water-soluble monomer is added to the emulsion obtained in the second step. The step of adding and then polymerizing the monomer component (ii) in the presence of a polymerization initiator.

The monomer component (ii) used in the third step contains a polymerizable crosslinkable monomer and a polymerizable water-soluble monomer, and if necessary, these single monomers It may also contain a monomer copolymerizable with the body (usually a non-crosslinkable hydrophobic monomer). As each of the above-mentioned monomers, the respective compounds forming the structural units (a), (b) and (c) constituting the polymer phase contained in the colorant can be applied.
By using the crosslinkable monomer, the seed polymer particles contained in the emulsion can be swollen, and the shape is shrunk as the polymerization proceeds in the third step, so that voids are easily formed inside. Can do.
The content of the crosslinkable monomer is preferably 1 to 60% by mass, more preferably 2 to 50% by mass, and still more preferably 5 to 5%, when the monomer component (ii) is 100% by mass. 40% by mass. When a crosslinkable monomer is used in the above range, hollow particles can be efficiently formed while proceeding with stable polymerization.
The content of the water-soluble monomer is preferably 0.5 to 15% by mass, more preferably 1 to 10% by mass, when the monomer component (ii) is 100% by mass. . When a water-soluble monomer is used within the above range, hollow particles can be efficiently formed while advancing stable polymerization without abnormally increasing the viscosity of the reaction system.

  The amount of the monomer component (ii) used is preferably 100 to 10,000 parts by mass, more preferably 200 to 8,000 parts by mass, when the seed polymer particles contained in the emulsion are 100 parts by mass. More preferably, it is 30 to 5,000 parts by mass. When the monomer component (ii) is used within the above range, hollow particles can be efficiently formed while a stable polymerization is proceeding.

In the third step, a polymerization initiator is usually used, and a hollow particle having a space portion (hollow) with a high porosity can be produced. Therefore, a water-soluble polymerization initiator is preferable.
Examples of water-soluble polymerization initiators include persulfates such as ammonium persulfate and potassium persulfate; 2,2′-azobis (2-amidinopropane) hydrochloride, 2,2′-azobis (2-amidinopropane) nitrate, and bissuccin An acid peroxide, a bisglutaric acid peroxide, etc. are mentioned. Also, organic peroxides such as benzoyl peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, tert-butyl perbenzoate and cumene hydroperoxide; persulfates such as ammonium persulfate and potassium persulfate; and hydrogen peroxide Oxidizing agents and bisulfites such as sodium bisulfite; divalent iron salts such as ferrous sulfate and ferrous chloride; amine compounds such as N, N-dimethylaniline and phenylmorpholine; cobalt naphthenate and naphthene A redox polymerization initiator which is a combination of reducing agents composed of metal naphthenate such as manganese acid and copper naphthenate can also be used.
The amount of the polymerization initiator used is preferably 0.1 to 3.0 parts by weight, more preferably 0.2 to 2.0 parts by weight, and more preferably 100 parts by weight of the monomer component (ii). Preferably it is 0.3-1.0 mass part.

  In the third step, it is preferable to perform a stirring step after mixing the seed polymer particles and the monomer component (ii). At this time, the temperature of the mixture is preferably 40 to 50 ° C. and the stirring time is preferably 1 to 5 hours. By performing this step, particles having a large space (hollow) inside the hollow particles can be obtained.

In the third step, the monomer component (ii) is usually polymerized while stirring the reaction system containing the polymerization initiator. As the polymerization proceeds, the crosslinkable monomer component on the surface of the seed polymer particles is polymerized to form a hard polymer layer, and then the monomer component (ii) inside the seed polymer particles is polymerized and contracts. By forming the space portion (hollow), an emulsion containing the colorant having an outer wall containing the polymer and pigment particles and at least one space portion inside thereof can be obtained.
The polymerization temperature is selected depending on the kind of the polymerization initiator, but is usually 20 ° C to 90 ° C, preferably 30 ° C to 85 ° C. The polymerization time is usually 1 to 12 hours, preferably 3 to 10 hours.

  In addition, another preferable method for producing the colorant includes a step of preparing an aqueous dispersion containing pigment particles and a monomer component (iii) containing a polymerizable crosslinkable monomer (hereinafter referred to as “preparation”). And a step of polymerizing the monomer component (iii) in the presence of a water-soluble polymerization initiator in this aqueous dispersion (hereinafter referred to as “monomer component polymerization step”), It is a method to prepare. According to this method, it is possible to obtain an emulsion in which the colorant is dispersed and contained only once in the monomer component polymerization step.

  In the preparation step, pigment particles, a monomer component (iii), an aqueous medium containing water, and other raw material components as necessary are used.

  The content of the crosslinkable monomer contained in the monomer component (iii) is preferably 1 to 60% by mass, more preferably 2 to 50% by mass, and further preferably 5 to 40% by mass. . When a crosslinkable monomer is used in the above range, hollow particles can be efficiently formed while proceeding with stable polymerization.

  Examples of the other monomer contained in the monomer component (iii) include the hydrophobic monomer and the water-soluble monomer described above. When a water-soluble monomer is used, the amount used is preferably 15% by mass or less, more preferably 10% by mass or less, based on the monomer component (iii). Therefore, the balance is a hydrophobic monomer.

In the preparation step, a dispersant, an emulsifier, a water-soluble polymerization initiator, an organic solvent, and the like can be used. Use of an organic solvent facilitates the production of hollow particles having a space portion (hollow) with a high porosity.
The amount of the dispersant used is preferably 0.1 to 40 parts by weight, more preferably 0.3 to 35 parts by weight, and still more preferably 0.3 to 30 parts by weight with respect to 100 parts by weight of the pigment particles. is there.
The amount of the emulsifier is preferably 0.1 to 30 parts by mass, more preferably 0.2 to 25 parts by mass, and still more preferably 0.3 to 100 parts by mass with respect to 100 parts by mass of the monomer component (i). 20 parts by mass.

  The polymerization initiator may be used as a raw material for preparing the aqueous dispersion, or may be used during the polymerization of the monomer component (iii) in the monomer component polymerization step.

  The method for preparing the aqueous dispersion can be the same as described above.

Next, the monomer component polymerization step is a step of polymerizing the monomer component (iii) in the presence of a water-soluble polymerization initiator in the aqueous dispersion obtained by the above preparation step.
The amount of the polymerization initiator used is preferably 0.1 to 3.0 parts by weight, more preferably 0.2 to 2.5 parts by weight, and more preferably 100 parts by weight of the monomer component (i). Preferably it is 0.3-2.0 mass parts.

  In the monomer component polymerization step, the monomer component (iii) is polymerized while stirring the reaction system to obtain an emulsion containing the colorant. The polymerization temperature is selected depending on the kind of the polymerization initiator, but is usually 20 ° C to 90 ° C, preferably 30 ° C to 85 ° C. The polymerization time is usually 1 to 12 hours, preferably 3 to 10 hours.

[2] Toner Manufacturing Method The toner manufacturing method of the present invention includes a step of mixing the toner particles obtained by the above-described toner particle manufacturing method and an external additive. The external additive is used for the purpose of improving the fluidity of the toner particles.

  Examples of the external additive include aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, tin oxide, zinc oxide and other metal oxides, nitrides such as silicon nitride, carbides such as silicon carbide, Inorganic metal salts such as calcium sulfate, barium sulfate and calcium carbonate, fatty acid metal salts such as zinc stearate and calcium stearate, carbon black, silica and the like are used. These are preferably used in the form of granules. Moreover, you may use the said compound which comprises this granular material individually or in combination of 2 or more types. Among the above compounds, silica particles are preferable, and hydrophobized silica particles are more preferable.

  The number average particle diameter of the external additive is preferably 1-1000 nm, more preferably 10-500 nm, and still more preferably 30-200 nm. The addition amount (external addition) is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and further preferably 1 to 5 parts by mass with respect to 100 parts by mass of the toner. Part.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. In the synthesis examples, examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified. Various measurements in the synthesis examples, examples, and comparative examples were performed by the following methods.

[Number average particle size]
The longest value of the particle diameters observed with a transmission electron microscope ("H-7650", manufactured by Hitachi High-Technologies Corporation) is measured as the particle diameter, and the above particle diameters of 100 particles present in the observation field of view are measured. The average value of was calculated.
[Percentage of total volume occupied by voids]
Ten particles observed by a transmission electron microscope (“H-7650”, manufactured by Hitachi High-Technologies Corporation) are arbitrarily selected, and for these particles, “the total volume of the space occupied by voids” is expressed by the following equation (1). "Percentage" was calculated.
Equation (1): [{(outer diameter ^{/ 2} of the particle) 4 [pi] 3/3} (total void volume) /] × 100
(Here, for example, when the number of voids inside the particle is one, it is calculated by {(inner diameter of void) ³ / (outer diameter of particle) ³ } × 100).
[Volume average particle diameter]
The particle size distribution was measured with a “Coulter Counter Multisizer II” (manufactured by Beckman-Coulter). (1) Use ISOTPN-II (manufactured by Beckman Coulter, Inc.) as the electrolyte, and (2) add 0.5 to 50 mg of a measurement sample as a dispersant in 2 ml of a 5% aqueous solution of sodium alkylbenzenesulfonate. Was added to 100 ml of the electrolytic solution and analyzed.
[Number variation coefficient]
Using the data obtained by the particle size distribution measuring apparatus, the calculation was performed according to the following formula.
Number variation coefficient (%) = (number standard deviation ÷ number average diameter) × 100

1. Manufacture of colorant (pigment composite hollow particles) Monomer component (i) consisting of 30 parts of styrene and 10 parts of n-butyl acrylate, 3 parts of t-dodecyl mercaptan, and copper phthalocyanine (β) (pigment particles) After mixing 50 parts of the name “CROMOPHTAL BLUE 4GNP” (manufactured by Ciba Specialty Chemicals) with a stirrer, 100 parts of a 10% polyvinyl alcohol aqueous solution (trade name “GOHSENOL GL03”, manufactured by Nippon Synthetic Chemical Co., Ltd.) and dodecylbenzene 10 parts of a 10% aqueous solution of sodium sulfonate and 280 parts of distilled water were added and mixed and dispersed using a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) as a stirrer to obtain a first emulsion. Thereafter, the obtained first emulsion was emulsified and dispersed at a pressure of 70 MPa using a high-pressure homogenizer (“Microfluidizer M110Y”, manufactured by Mizuho Kogyo Co., Ltd.) to obtain an emulsified dispersion. The emulsified dispersion was put into a separable flask and purged with nitrogen while stirring. Then, 5 parts of AIBN (azobisisobutyronitrile) was added as an oil-soluble initiator, and polymerization was performed at 75 ° C. for 4 hours to obtain seed particles. A second emulsion containing was obtained (polymerization conversion 98.4%). The solid content concentration of the obtained second emulsion was adjusted to 20%.
When the seed particles in the obtained second emulsion were observed with a transmission electron microscope (“H-7650”, manufactured by Hitachi High-Technologies Corporation), the number average particle diameter was 160 nm. The obtained seed particles were so-called solid particles in which no voids were formed.
Table 1 shows the blending amounts of the monomer component, pigment particles, polymerization initiator, and the like used for the synthesis of the second emulsion.

200 parts of the second emulsion containing seed particles obtained as described above, 42 parts of methyl methacrylate, 30 parts of divinylbenzene, 6 parts of n-butyl acrylate and 2 parts of acrylic acid, and distillation 300 parts of water was mixed and mixed and dispersed with a stirrer to obtain a dispersion. Thereafter, the mixture was emulsified and dispersed at a pressure of 70 MPa using a high-pressure homogenizer (“Microfluidizer M110Y”, manufactured by Mizuho Kogyo Co., Ltd.) to obtain an emulsified dispersion. This emulsified dispersion was put into a separable flask and purged with nitrogen while stirring. Next, 20 parts of a 3% aqueous solution of potassium persulfate as a water-soluble initiator was added, and polymerization was performed at 75 ° C. for 4 hours to obtain a dispersion in which particles were dispersed. When the particles in the obtained dispersion were observed with a transmission electron microscope, it was confirmed to be pigment-complexed hollow particles having a number average particle diameter of 235 nm and an inner diameter of 130 nm. Further, the ratio of the total volume occupied by the voids of the pigment composite hollow particles was 16.9%.
Thereafter, the pigment composite hollow particle dispersion obtained above was filtered, washed and dried to isolate the pigment composite hollow particles.
In addition, Table 2 shows the raw materials and blending amounts used for the production of the pigment composite hollow particles.

2. Production and evaluation of toner particles
<Example 1>
(1) Preparation of Colorant Dispersion 10 parts of the colorant (pigment composite hollow particles containing 20% pigment particles) obtained above, 50 parts of distilled water, and a salicylic acid compound aluminum complex (trade name “Bontron”) E-88 "(manufactured by Orient Chemical Co., Ltd.) 0.95 parts, was charged into a temperature-adjustable stirring tank and stirred to be evenly blended.

(2) Preparation of dispersion stabilizer composition 253.7 parts of distilled water and 3.6 parts of trisodium phosphate were mixed with a temperature-adjustable stirring tank (tank 1) equipped with a full zone blade (manufactured by Shinko Pantech Co., Ltd.). ), The temperature was raised to 60 ° C., and the mixture was stirred at a low speed until trisodium phosphate was completely dissolved. Next, 2.1 parts of calcium chloride was added and stirred for 30 minutes at a rotation speed of 170 rotations / minute to obtain a dispersion stabilizer composition which was an aqueous suspension containing hydroxyapatite fine particles.

(3) Preparation of polymerization initiator solution 3.0 parts of 2,2′-azobis- (2,4-dimethylvaleronitrile) and 11.9 parts of styrene were stirred and mixed to prepare a polymerization initiator solution. .

(4) Granulation step 83 parts of styrene, 17 parts of n-butyl acrylate, and 5.0 parts of terephthalic acid-propylene oxide modified bisphenol A polymer (average molecular weight: 7500, acid value: 10 mgKOH / g) as a polar resin And 60.95 parts of the above colorant dispersion were put into a stirring vessel capable of adjusting the temperature and stirred and mixed at room temperature. Thereafter, the temperature of the mixture was raised to 60 ° C., 13.75 parts of behenyl behenate (melting point: 73 ° C.) was added to the stirring tank, and stirring was continued to obtain a monomer composition (see Table 3). ).
Next, the dispersion stabilizer composition in the tank 1 was kept at 60 ° C., and the monomer composition at 60 ° C. was charged therein. And it stirred at 5000 rpm in HIGH-FLEX DISPERSER (made by a tabletop coreless SMT Co., Ltd.), and prepared the preliminary dispersion liquid which is a mixture of a dispersion stabilizer composition and a monomer composition.
Thereafter, the preliminary dispersion is dispersed for 10 minutes at 60 ° C. and 10,000 rpm using a disperser (“AUOT HOMO MIXSER”, manufactured by Tokushu Kika Kogyo Co., Ltd. <currently Primex Co., Ltd.). The agent solution was charged. Further, the mixture was further stirred to obtain a dispersion containing a granulated product obtained by contacting the colorant and the monomer.

(5) Polymerization process The liquid temperature was heated to 60 degreeC, stirring the dispersion liquid containing the said granulated material, and superposition | polymerization was performed at this temperature for 5 hours. Thereafter, the temperature of the reaction system was raised to 80 ° C., and the polymerization was further continued for 4 hours to obtain a dispersion of composite fine particles containing the polymer and the colorant.

(6) Washing / Solid-Liquid Separation / Drying Step After adding hydrochloric acid to the resulting composite fine particle dispersion and stirring to dissolve the hydroxyapatite covering the composite fine particles, a pressure filter, a filter press, a belt filter, etc. Solid-liquid separation was performed with a known filter to obtain polymer fine particles. This was put into water and stirred to obtain a dispersion again, followed by solid-liquid separation with the above filter. After redispersion of polymer fine particles in water and solid-liquid separation are repeated until the hydroxyapatite is sufficiently removed, the final solid-liquid separation of the polymer fine particles is performed using a fluidized bed dryer or airflow drying. Toner particles sufficiently dried by a known drying means such as a machine were obtained. When the particle size distribution of the obtained toner particles was measured, the volume average particle size was 6.2 μm, the number variation coefficient was 25.2%, and the particle size distribution was extremely sharp, and almost no classification step was required. . Further, in the microscopic observation, the shape of the obtained toner particles was a true sphere, and no irregularly shaped particles or the like were observed.
Table 3 shows the blending components and the blending amount of each component.

The resulting toner particles were evaluated for color development and hiding properties as toner particles by the following method. The results are shown in Table 4.
The toner particles are filled into a modified printer “DocuPrint C3250” manufactured by Fuji Xerox Co., Ltd., and “white fine paper”, “black fine paper” and “red fine paper” manufactured by Oji Paper Co., Ltd., and Epson are used as printing paper (printing media). It was printed on a transparent “OHP sheet”. And the hue of the printing part was visually observed.
(1) Color developability According to the above visual observation, the color developability is good and the color is bright, “◯”, and the color developability is slightly good, “△”, the color developability is poor and the color is dull. In the case, it was determined as “×”.
(2) Concealment According to the above visual observation, there is concealment, and “◯” is displayed when the color of the printing paper is not seen through in the printing unit, “△” when the color of the printing paper is seen through slightly, printing paper When the color of was visible, it was determined as “x”.

<Example 2>
In Example 2, as shown in Table 3, as a dispersion of the colorant, instead of 50 parts of distilled water used in Example 1, 50 parts of styrene was used to disperse 10 parts of the colorant. An agent dispersion was used. And the monomer composition was obtained by replacing 83 parts of styrene used in Example 1 with 33 parts of styrene. Using this monomer composition, toner particles were obtained by the same production method as in Example 1. When the particle size distribution of the obtained toner particles was measured, the volume average particle size was 6.8 μm, the number variation coefficient was 25.3%, and the particle size distribution was very sharp, and almost no classification step was required. . Further, in the microscopic observation, the shape of the obtained toner particles was a true sphere, and no irregularly shaped particles or the like were observed.
The resulting toner particles were evaluated for color development and hiding properties in the same manner as in Example 1. The results are shown in Table 4.

<Example 3>
In Example 3, the preparation of the dispersion of the colorant in the aqueous medium performed in Example 1 (preparation of the dispersion of the colorant) was not performed, and as shown in Table 3, 10 parts of the colorant were salicylic acid compounds. A colorant mixture in which 0.95 parts of an aluminum complex was mixed was obtained, and this colorant mixture was used in place of the colorant dispersion used in Example 1. Otherwise, toner particles were obtained by the same production method as in Example 1. When the particle size distribution of the obtained toner particles was measured, the volume average particle size was 7.2 μm, the number variation coefficient was 25.7%, and the particle size distribution was very sharp, and almost no classification step was required. . Further, in the microscopic observation, the shape of the obtained toner particles was a true sphere, and no irregularly shaped particles or the like were observed.
The resulting toner particles were evaluated for color development and hiding properties in the same manner as in Example 1. The results are shown in Table 4.

<Comparative Example 1>
In Comparative Example 1, as shown in Table 3, in place of the colorant (pigment composite hollow particles) used in Example 1, 1.67 parts of the pigment particles “CROMOPHTAL BLUE 4GNP” were dispersed alone. A dispersion was used. Then, the monomer composition was obtained by replacing 83 parts of styrene used in Example 1 with 91.33 parts of styrene. Using this monomer composition, toner particles were obtained by the same production method as in Example 1. When the particle size distribution of the obtained toner particles was measured, the volume average particle size was 6.5 μm, the number variation coefficient was 26.0%, and the particle size distribution was extremely sharp, and almost no classification step was required. . Further, in the microscopic observation, the shape of the obtained toner particles was a true sphere, and no irregularly shaped particles or the like were observed.
The resulting toner particles were evaluated for color development and hiding properties in the same manner as in Example 1. The results are shown in Table 4.

  As is apparent from Table 4, in Comparative Example 1, for example, in the concealment evaluation “red fine paper”, the red color of the printing paper appeared to be transparent purple. For other white, black, and OHP, the coloring and hiding properties were not sufficient. On the other hand, Examples 1-3 were excellent in concealing property and coloring property.

Claims (8)

A granulating step of mixing a colorant, a monomer and an aqueous medium to obtain a granulated product containing the colorant and the monomer;
A polymerization step of polymerizing the monomer contained in the granulated product,
With
The colorant is a pigment composite hollow particle in which pigment particles are dispersed in a polymer phase, and at least one void is formed therein.
A method for producing toner particles, comprising producing toner particles in which the colorant is dispersed in a polymer derived from the monomer.   The method for producing toner particles according to claim 1, wherein the number average particle diameter of the pigment-complexed hollow particles is 20 nm to 100 μm.   The content of the pigment particles contained in the pigment composite hollow particles is 3 to 80 parts by mass when the polymer constituting the polymer phase is 100 parts by mass. A method for producing toner particles.   The ratio of the total amount of the volume occupied by the voids of the pigment composite hollow particles is 5 to 90% by volume when the volume of the entire pigment composite hollow particles is 100% by volume. 2. A method for producing toner particles according to 1.   The method for producing toner particles according to claim 1, wherein the granulated product further contains a charge control agent and / or a release agent.   The method for producing toner particles according to claim 1, wherein in the granulation step, a colorant, a monomer, and an aqueous medium are mixed in the presence of a dispersion stabilizer.   The method for producing toner particles according to claim 6, wherein the dispersion stabilizer is hydroxyapatite.   A method for producing toner, comprising a step of mixing toner particles obtained by the method for producing toner particles according to claim 1 and an external additive.