JP6137964B2 - Pigment dispersion method, toner production method, pigment dispersant and pigment dispersion - Google Patents

Description

  The present invention relates to a pigment dispersion method, a pigment dispersant, and a pigment dispersion used in a process for producing paints, inks, and toners. The present invention also relates to a method for producing toner used in electrophotography, electrostatic recording, magnetic recording, and toner jet.

  C. I. Pigment Red 31, C.I. I. Pigment Red 150, C.I. I. Pigment Red 176, C.I. I. Since azo pigments such as Pigment Red 269 are generally inexpensive and have high coloring power, they are used in various fields as colorants. For example, it is used in the fields of paints, ink for inkjet printers, toner for electrophotography, color filters, and the like. When a pigment is used in such a field, it is necessary to refine the pigment in various media in order to improve spectral characteristics such as coloring power and transparency. However, azo pigments may be difficult to miniaturize, and in order to make them finer to the primary particle level of the pigment, the dispersion time in the dispersion process is greatly extended, and the production cost is increased by introducing complicated dispersion equipment. There is a concern that this will increase.

  Furthermore, even if the pigment can be refined to the level of primary particles, it may re-aggregate in the subsequent manufacturing process, resulting in a reduction in coloring power and transparency.

  Also in the toner, the pigment dispersion process is a very important manufacturing process.

  For example, a suspension for producing toner particles by polymerizing a polymerizable monomer by applying heat in a state where a polymerizable monomer composition containing a pigment and a polymerizable monomer is dispersed in an aqueous medium. In the polymerization method, reaggregation of the pigment tends to occur. Specifically, even if the pigment is sufficiently dispersed in the pigment dispersion step, the pigment tends to reaggregate when other materials are added after the dispersion step or when heated in the polymerization step.

  In addition, in the solution suspension method in which toner particles are obtained by granulating a solution obtained by dissolving a toner material in an organic solvent in an aqueous medium, and then removing the solvent from the solution, the pigment is removed in the solvent removal step. Reaggregation is likely to occur.

  In order to improve such problems, various pigment dispersion methods have been proposed.

  Patent Documents 1 and 2 disclose that a specific monoazo pigment is dispersed in the presence of an oxycarboxylic acid. Although this method can certainly improve the pigment dispersibility, further improvement of the pigment dispersibility is demanded.

  Patent Document 3 discloses a method for adjusting a thixotropy value of a master batch to 3 to 7 by adding a salicylic acid derivative in a manufacturing method of a polymerized toner in which toner is obtained through a manufacturing process using a master batch. This method is to improve the pigment dispersibility by adjusting the thixotropy value by setting the pigment to a specific shape and particle size, but it is necessary that the pigment has relatively acicular crystals. In the case of pigments that are not shaped crystals, it is difficult to achieve sufficient pigment dispersion.

JP 2002-182420 A JP 2002-72569 A JP 2000-19777 A

  An object of the present invention is to provide a pigment dispersion method which has good pigment dispersion and can maintain good pigment dispersion over a long period of time.

  An object of the present invention is to provide a method for producing a toner excellent in pigment dispersion.

  An object of the present invention is to provide a pigment dispersant that is excellent in pigment dispersion and can maintain good pigment dispersion over a long period of time.

  An object of the present invention is to provide a pigment dispersion that is excellent in pigment dispersion and can maintain good pigment dispersion over a long period of time.

  The above object is achieved by the present invention described below. That is, the first aspect of the present invention is a pigment dispersion method in which an organic solvent, a pigment, and a pigment dispersant are mixed and stirred to disperse the pigment in the organic solvent. I. Pigment Red 31, C.I. I. Pigment Red 150, C.I. I. Pigment Red 176 and C.I. I. Pigment Red 269, which is at least one pigment selected from the group consisting of Pigment Red 269, wherein the pigment dispersant is an aromatic oxycarboxylic acid represented by the following formula (1).

    Formula (1)

  The second aspect of the present invention also relates to a toner production method including a pigment dispersion step of obtaining a pigment dispersion by dispersing a pigment in an organic solvent by the pigment dispersion method of the first aspect of the present invention.

  The third aspect of the present invention is a pigment dispersant for dispersing a pigment in an organic solvent, wherein the pigment is C.I. I. Pigment Red 31, C.I. I. Pigment Red 150, C.I. I. Pigment Red 176 and C.I. I. The pigment dispersant is at least one pigment selected from the group consisting of Pigment Red 269, and the pigment dispersant is an aromatic oxycarboxylic acid represented by the above formula (1).

  The fourth aspect of the present invention is a pigment dispersion obtained by dispersing a pigment in an organic solvent in the presence of a pigment dispersant, wherein the pigment is C.I. I. Pigment Red 31, C.I. I. Pigment Red 150, C.I. I. Pigment Red 176 and C.I. I. The pigment dispersion is at least one pigment selected from the group consisting of Pigment Red 269, and the pigment dispersant is an aromatic oxycarboxylic acid represented by the above formula (1).

  According to the present invention, by using a specific aromatic oxycarboxylic acid, C.I. I. Pigment Red 31, C.I. I. Pigment Red 150, C.I. I. Pigment Red 176 and C.I. I. Pigment Red 269 has good pigment dispersion and can provide a pigment dispersion method, a pigment dispersant, and a pigment dispersion that can maintain good pigment dispersion over a long period of time. Further, it is possible to provide a method for producing a toner having good pigment dispersion.

It is an enlarged view of the developing unit of the electrophotographic apparatus. 1 is a cross-sectional view of an electrophotographic apparatus using an image forming method of the present invention.

<Pigment dispersion method, pigment dispersant and pigment dispersion>
The pigment dispersion method of the present invention is a pigment dispersion method in which an organic solvent, a pigment, and a pigment dispersant are mixed and stirred to disperse the pigment in the organic solvent. I. Pigment Red 31, C.I. I. Pigment Red 150, C.I. I. Pigment Red 176 and C.I. I. Pigment Red 269, and at least one pigment selected from the group consisting of Pigment Red 269, wherein the pigment dispersant is an aromatic oxycarboxylic acid represented by the following formula (1).

    Formula (1)

  The pigment dispersant of the present invention is a pigment dispersant for dispersing a pigment in an organic solvent, and the pigment is C.I. I. Pigment Red 31, C.I. I. Pigment Red 150, C.I. I. Pigment Red 176 and C.I. I. Pigment Red 269, at least one pigment selected from the group consisting of Pigment Red 269, wherein the pigment dispersant is an aromatic oxycarboxylic acid represented by the above formula (1).

  The pigment dispersion of the present invention is a pigment dispersion obtained by dispersing a pigment in an organic solvent in the presence of a pigment dispersant. I. Pigment Red 31, C.I. I. Pigment Red 150, C.I. I. Pigment Red 176 and C.I. I. Pigment Red 269, at least one pigment selected from the group consisting of Pigment Red 269, wherein the pigment dispersant is an aromatic oxycarboxylic acid represented by the above formula (1).

  In the present invention, examples of the pigment that can sufficiently exhibit the effect of improving the pigment dispersion by the pigment dispersant represented by the above formula (1) include C.I. I. Pigment Red 31, C.I. I. Pigment Red 150, C.I. I. Pigment Red 176, C.I. I. Pigment Red 269. These pigments may be used alone or in combination of two or more.

  The mechanism by which the dispersibility in the organic solvent is improved by the aromatic oxycarboxylic acid represented by the above formula (1) is not yet clear, but the present inventors consider the following as follows. .

  The aromatic oxycarboxylic acid represented by the above formula (1) is salicylic acid into which two methylbenzyl groups are introduced.

  Since the methylbenzyl group of the aromatic oxycarboxylic acid represented by the above formula (1) is likely to interact with the organic solvent, the aromatic oxycarboxylic acid represented by the above formula (1) is easily compatible with the organic solvent. have.

  It is common that the pigment has a structure represented by the following formula (2). An interaction due to intermolecular force occurs between the nitrogen atom present in the amide bond and azo bond contained in the formula (2) and the polar site (carboxyl group and hydroxyl group) present in the aromatic oxycarboxylic acid.

  Therefore, it is considered that the dispersibility of the pigment in the organic solvent is improved by the adsorption of the aromatic oxycarboxylic acid of the above formula (1), which is easily compatible with the organic solvent, by the intermolecular force.

    Formula (2)

  In addition, since these pigments are flat crystals, the thixotropy value of the master batch tends to be low. Therefore, these pigments are disadvantageous for the dispersibility in the organic solvent, but the dispersibility of the pigment in the organic solvent is improved by using the aromatic oxycarboxylic acid represented by the above formula (1). be able to.

  The mass ratio of the pigment to the aromatic oxycarboxylic acid (the mass of the pigment: the mass of the aromatic oxycarboxylic acid) is preferably 99.0: 1.0 to 70.0: 30.0.

  When the mass ratio of the pigment to the aromatic oxycarboxylic acid is within the above range, the dispersibility of the pigment in the organic solvent can be further improved by the aromatic oxycarboxylic acid. In addition, when a toner is prepared using a pigment dispersion obtained by dispersing a pigment in an organic solvent in the presence of an aromatic oxycarboxylic acid that is a pigment dispersant, the toner is charged by the aromatic oxycarboxylic acid. Effects on fixing properties and fixing properties can be further reduced.

  A known organic solvent can be used as the organic solvent.

  For example, a polymerization solvent used in the toner production method can be used. Specifically, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2- Methyl-1-butanol, isopentyl alcohol, tert-pentyl alcohol, 1-hexanol, 2-methyl 1-pentanol, 4-methyl-2-pentanol, 2-ethylbutanol, 1-heptanol, 2-heptanol, 3 -Alcohols such as heptanol, 2-octanol, 2-ethyl 1-hexanol, benzyl alcohol, cyclohexanol; and agents such as methyl cellosolve, cellosolve, isopropyl cellosolve, butyl cellosolve, diethylene glycol monobutyl ether Alcohols; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone; esters such as ethyl acetate, butyl acetate, ethyl propionate, cellosolve acetate; pentane, 2-methylbutane, n-hexane, cyclohexane, 2-methyl Pentane, 2,2-dimethylbutane, 2,3-dimethylbutane, heptane, n-octane, isooctane, 2,2,3-trimethylpentane, decane, nonane, cyclopentane, methylcyclopentane, methylcyclohexane, ethylcyclohexane, Aliphatic or aromatic hydrocarbons such as p-menthane, bicyclohexyl, benzene, toluene, xylene, ethylbenzene; halo such as carbon tetrachloride, trichloroethylene, chlorobenzene, tetrabromoethane Hydrocarbons; ethers such as ethyl ether, dimethyl ether and trioxane tetrahydrofuran; acetals such as methylal and diethyl acetal; fatty acids such as formic acid, acetic acid and propionic acid; nitropropene, nitrobenzene, dimethylamine, monoethanolamine, Mention may be made of organic compounds containing sulfur or nitrogen such as pyridine, dimethylformamide, dimethyl sulfoxide.

  Moreover, it is also possible to use the polymerizable monomer used when manufacturing a toner by the suspension polymerization method mentioned later as an organic solvent. Specifically, styrene monomers such as styrene, o-methyl styrene, m-methyl styrene, p-methoxy styrene, p-ethyl styrene, p-tertiary butyl styrene; acrylic acid, methyl acrylate, acrylic acid Acrylic esters such as ethyl, n-butyl acrylate, n-propyl acrylate, isobutyl acrylate, octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate Methacrylic acid, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stear methacrylate , Methacrylates such as phenyl methacrylate, dimethylaminomethyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, benzyl methacrylate; hydroxyethyl esters such as 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate Compounds containing nitrogen atoms such as acrylonitrile, methacrylonitrile, acrylamide; alkyl vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl ether, isobutyl ether; β-chloroethyl vinyl ether, phenyl vinyl ether, p-methylphenyl Ether, p-chlorophenyl ether, p-bromophenyl ether, p-nitrophenyl vinyl ether Ter, phenyl vinyl ethers such as p-methoxyphenyl vinyl ether; diene compounds such as butadiene; acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, monobutyl itaconic acid, monobutyl maleate, phosphoric acid-containing single amount Body (specifically, acid phosphooxyethyl methacrylate, acid phosphooxypropyl methacrylate), sulfonic acid group-containing monomer, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, acryloylmorpholine, 2-vinylpyridine, 3-vinylpyridine, Examples include 4-vinylpyridine, N-vinylpyrrolidone, 2-vinylimidazole, N-methyl-2-vinylimidazole, and N-vinylimidazole.

  These polymerizable monomers can be used alone or in combination of two or more, and are appropriately selected so as to obtain a suitable polymer composition capable of obtaining preferable characteristics. Can be used.

  Among these organic solvents, the organic solvent is preferably an aromatic organic solvent, more preferably styrene, in order to improve pigment dispersion. Since the aromatic oxycarboxylic acid represented by the above formula (1) has two methylbenzyl groups, it has a structure in which π-π interaction between molecules tends to be stronger. Therefore, the aromatic oxycarboxylic acid represented by the above formula (1) is more compatible with the aromatic organic solvent, and the pigment dispersibility is further improved. Further, among them, when the organic solvent is styrene, the structure is closer to that of the methylbenzyl group, so that the pigment dispersibility is further improved.

  In the present invention, a crosslinking agent may be used to increase the mechanical strength of the toner particles and to control the molecular weight of the binder resin of the toner.

  The following are mentioned as a crosslinking agent used for this invention.

  Examples of the bifunctional crosslinking agent include divinylbenzene, bis (4-acryloxypolyethoxyphenyl) propane, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1, Each of 5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 200, # 400, # 600 Diacrylate, dipropylene glycol diacrylate, polypropylene glycol diacrylate, polyester-type diacrylate (MANDA Nippon Kayaku), and the above diac Rates include those instead dimethacrylate.

  Examples of the polyfunctional crosslinking agent include pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate and its methacrylate, 2,2-bis (4-methacryloxy). Polyethoxyphenyl) propane, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate and triallyl trimellitate.

  The addition amount of these crosslinking agents is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

<Toner production method>
The toner production method of the present invention is characterized by having a pigment dispersion step of obtaining a pigment dispersion by dispersing a pigment in an organic solvent by the above-described pigment dispersion method.

  Examples of the toner production method include the suspension polymerization method and the dissolution suspension method described below.

[Suspension polymerization method]
First, the first toner production method (suspension polymerization method) will be described.

  The first toner production method is a granulation method in which an organic solvent has a polymerizable monomer mainly composed of styrene, and the pigment dispersion is dispersed in an aqueous medium to produce particles of the pigment dispersion. And a polymerization step of polymerizing the polymerizable monomer in the particles of the obtained pigment dispersion.

  Specifically, the pigment, the aromatic oxycarboxylic acid represented by the above formula (1), and other materials as necessary are dissolved or dispersed in the polymerizable monomer. Furthermore, a polymerization initiator is dissolved in this to prepare a polymerizable monomer composition. As a device for dispersing the pigment, a known dispersion device can be used in consideration of the viscosity of the dispersion and the dispersion time.

  The polymerizable monomer composition is added to an aqueous medium having a dispersant for dispersing the polymerizable monomer composition and granulated. Thereafter, the polymerizable monomer in the polymerizable monomer composition is polymerized to form particles, and the obtained particles can be filtered, washed, and dried to obtain toner particles.

  Here, “the main component of styrene” means that styrene is 50 parts by mass or more with respect to 100 parts by mass of the polymerizable monomer.

(Polymerization initiator)
The polymerization initiator may be added at the same time when other additives are added to the polymerizable monomer, or may be mixed immediately before granulating the polymerizable monomer composition in the aqueous medium. Good. Further, immediately after granulation, a polymerization initiator dissolved in a polymerizable monomer or solvent may be added before starting the polymerization reaction.

  The following are mentioned as a polymerization initiator used when manufacturing a toner by a suspension polymerization method.

  2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis Azo or diazo polymerization initiators such as -4-methoxy-2,4-dimethylvaleronitrile and azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl Peroxide-based polymerization initiators such as peroxide, lauroyl peroxide, tert-butyl-peroxypivalate.

  The amount of these polymerization initiators to be used varies depending on the desired degree of polymerization, but is generally 3 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer. preferable. The kind of the polymerization initiator is slightly different depending on the polymerization method, but is selected with reference to the 10-hour half-life temperature and used alone or in combination.

(Dispersant)
As the dispersant for dispersing the polymerizable monomer composition in the aqueous medium, known inorganic and organic dispersants can be used.

  Examples of the inorganic dispersant include the following.

  Tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, magnesium carbonate, calcium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina .

  On the other hand, examples of the organic dispersant include the following.

  Polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, carboxymethyl cellulose sodium salt, starch.

  Also, commercially available nonionic, anionic, and cationic surfactants can be used as a dispersant for dispersing the polymerizable monomer composition in the aqueous medium. Examples of such surfactants include the following.

  Sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, calcium oleate.

  Among the dispersants for dispersing the above polymerizable monomer composition in an aqueous medium, an inorganic poorly water-soluble dispersant is preferable, and a poorly water-soluble inorganic dispersant that is soluble in an acid is used. More preferably, it is used.

  The amount of the dispersant used for dispersing these polymerizable monomer compositions in the aqueous medium is 0.2 parts by mass or more and 2.0 parts by mass with respect to 100 parts by mass of the polymerizable monomer. The following is preferable. Further, in the aqueous dispersion medium in which the polymerizable monomer composition is granulated in the aqueous medium, 300 parts by mass or more and 3,000 parts by mass or less of water are added to 100 parts by mass of the polymerizable monomer composition. It is preferable to use it to prepare an aqueous dispersion medium.

  In the present invention, when preparing an aqueous dispersion medium in which the above-mentioned poorly water-soluble inorganic dispersant is dispersed, a commercially available dispersant may be used as it is. In addition, in order to obtain particles of a dispersant having a fine and uniform particle size, an aqueous dispersion medium may be prepared by generating the slightly water-soluble inorganic dispersant in a liquid medium such as water under high-speed stirring. . For example, when tricalcium phosphate is used as a dispersant, it is possible to form a tricalcium phosphate microparticle by mixing a sodium phosphate aqueous solution and a calcium chloride aqueous solution under high-speed stirring.

(wax)
The toner particles may contain a known wax. Examples of the wax include the following.

  Petroleum waxes and derivatives thereof such as paraffin wax, microcrystalline wax, petrolactam; montan wax and derivatives thereof; hydrocarbon waxes and derivatives thereof according to the Fischer-Tropsch method; polyolefin waxes and derivatives thereof such as polyethylene wax and polypropylene wax; Natural waxes such as waxes and candelilla waxes and derivatives thereof; higher aliphatic alcohols; fatty acids such as stearic acid and palmitic acid; acid amide waxes; ester waxes; hydrogenated castor oil and derivatives thereof; plant waxes;

  Examples of the derivatives include oxides, block copolymers with vinyl monomers, and graft modified products.

  Among these, ester wax and hydrocarbon wax are preferable from the viewpoint of excellent releasability, and hydrocarbon wax is more preferable.

  The content of the wax in the toner is preferably 4 parts by mass or more and 25 parts by mass or less with respect to 100 parts by mass of the binder resin. When the wax is within the above range, the wax is moderately bleed when the toner is heated and pressurized, and the wrapping resistance is further improved. Further, even when the toner is subjected to stress during development or transfer, the exposure of wax to the toner surface is small, and each toner can obtain uniform triboelectric chargeability.

(Polar resin)
The toner particles may contain a known polar resin. The polar resin means a resin having a polar group such as a carboxyl group, a hydroxyl group, or a sulfonic acid group. When producing a toner by suspension polymerization, it is possible to form toner particles having various structures by adjusting the type and polarity of the polar resin. For example, a thin layer shell made of a polar resin can be formed on the toner particles, or a layer in which the polar resin exists can be formed so that the concentration of the polar resin gradually increases from the toner particle center toward the surface. . By adding a polar resin and imparting a core-shell structure to the toner particles, both the durability and the fixing property of the toner can be achieved. Further, by adding a polar resin, the toner particle size distribution and particle size can be controlled.

  The addition amount of the polar resin is preferably 1 to 30 parts by mass with respect to 100 parts by mass of the binder resin. By setting the addition amount of the polar resin within the above range, the chargeability and durability of the toner are improved. Moreover, it is preferable that the weight average molecular weight Mw of polar resin is 5000 or more and 50000 or less. When the weight average molecular weight of the polar resin is within the above range, when the toner is produced in an aqueous medium, the viscosity can be made favorable for dispersing the pigment in the toner composition. Therefore, it is possible to disperse the pigment in the toner particles in a good state.

  The polar resin is preferably a vinyl polymer or a polyester resin.

  In the vinyl polymer, a styrene copolymer is more preferable. Polymerizable monomers used with styrene monomers to form styrenic copolymers include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, acrylic acid- A monocarboxylic acid having a double bond such as 2-ethylhexyl, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide or a substituted product thereof; Dicarboxylic acids having a double bond such as acid, butyl maleate, methyl maleate and dimethyl maleate and their substitutes; vinyl esters such as vinyl chloride, vinyl acetate and vinyl benzoate; and esters such as ethylene, propylene and butylene. Ren olefin; vinyl methyl ketone, such as vinyl vinyl hexyl ketone; include such sulfonic acid group-containing monomers of styrene sulfonic acid, vinyl methyl ether, vinyl ethyl ether, vinyl propionate ether.

  It is also possible to add a crosslinking agent to the polar resin. As the crosslinking agent, a compound having two or more polymerizable double bonds is used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate and 1,3-butanediol dimethacrylate; divinylaniline and divinyl ether , Divinyl sulfide, divinylsulfone and the like; compounds having three or more vinyl groups. These crosslinking agents can be used alone or as a mixture.

  Moreover, when using a polyester resin as a polar resin, the following are mentioned as an alcohol component used in order to form a polyester resin.

  Examples of the dihydric alcohol component include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis (4-hydroxyphenyl). ) Propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene (2.0) -2,2-bis (4) -Alkylene oxide adducts of bisphenol A such as hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane; ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol 1,3-propylene glycol, 1,4-butanediol, neopen Aliphatics such as glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol Diols such as bisphenol A and bisphenol A such as hydrogenated bisphenol A.

  Examples of the trivalent or higher alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol. 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene Can be mentioned.

  Moreover, the following are mentioned as an acid component used in order to form a polyester resin.

  Aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid and pyromellitic acid; those having 1 to 20 carbon atoms such as fumaric acid, maleic acid, adipic acid, succinic acid, dodecenyl succinic acid, octenyl succinic acid Aliphatic polycarboxylic acids of succinic acid substituted with alkyl groups or alkenyl groups of 2 to 20 carbon atoms; anhydrides of these acids and alkyl (1-8 carbon atoms) esters of these acids.

  Among them, in particular, a polyester resin obtained by polycondensation using a bisphenol derivative as an alcohol component and a divalent or higher carboxylic acid or acid anhydride thereof or a lower alkyl ester thereof as an acid component can be preferably used. .

(Charge control agent)
The toner particles may contain a known charge control agent.

  As the charge control agent, a known one can be used, and a charge control agent that has a high charging speed and can stably maintain a constant charge amount is particularly preferable. Further, when the toner is produced by a suspension polymerization method, a charge control agent having a low polymerization inhibitory property and substantially free from a solubilized product in an aqueous dispersion medium is particularly preferable.

  Among the charge control agents, examples of the charge control agent that controls the toner to be negatively charged include organometallic compounds and chelate compounds. Specific examples include a monoazo metal compound, an acetylacetone metal compound, an aromatic oxycarboxylic acid, an aromatic dicarboxylic acid, an oxycarboxylic acid, and a dicarboxylic acid-based metal compound. Other examples include aromatic oxycarboxylic acids, aromatic mono- and polycarboxylic acids and metal salts thereof, anhydrides, esters, and phenol derivatives such as bisphenol. Furthermore, urea derivatives, metal-containing salicylic acid compounds, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, and calixarene are also included.

  Examples of the charge control agent for controlling the toner to be positively charged include nigrosine-modified products such as nigrosine and fatty acid metal salts; guanidine compounds; imidazole compounds; tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutyl. Quaternary ammonium salts such as ammonium tetrafluoroborate and onium salts such as phosphonium salts and analogs thereof and lake pigments thereof; triphenylmethane dyes and lake lake pigments (as rake agents include phosphotungstic acid, Phosphomolybdic acid, phosphotungstic molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.); metal salts of higher fatty acids; dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide Diorganotin oxides such as id, dibutyltin tin borate, dioctyl tin borate, such as diorganotin tin borate such dicyclohexyl tin borate, and the like.

  In addition, the charge control agents can be used alone or in combination of two or more.

  Among these charge control agents, metal-containing salicylic acid compounds are preferable, and the metal is particularly preferably aluminum or zirconium. The most preferred charge control agent is an aluminum 3,5-di-tert-butylsalicylate compound.

  The addition amount of the charge control agent is preferably 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 binder resin.

  It is also possible to use a resin charge control agent as the charge control agent. As the resin charge control agent, for example, a polymer having a sulfonic acid group, a sulfonic acid group salt or a sulfonic acid ester group in the side chain is preferably used. Among them, it is particularly preferable to use a polymer or copolymer of a sulfonic acid group, a sulfonic acid group, or a sulfonic acid ester group. When the toner of the present invention is produced by the suspension polymerization method, by adding the above polymer, the stabilization of granulation promotes the core-shell structure of the toner particles in the polymerization stage rather than the basis. Therefore, it is possible to further improve both the durability and the fixing property of the toner.

  Examples of the polymerizable monomer having a sulfonic acid group, a sulfonic acid group salt or a sulfonic acid ester group include styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, and 2-methacrylamide-2-methylpropanesulfonic acid. , Vinyl sulfonic acid, methacryl sulfonic acid and alkyl esters thereof.

  Even if the polymer containing a sulfonic acid group, a sulfonic acid group salt or a sulfonic acid ester group is a homopolymer of the polymerizable monomer, the polymerizable monomer and other polymerizable monomers It may be a copolymer of As the polymerizable monomer that forms a copolymer with the polymerizable monomer, there is a vinyl polymerizable monomer, and a monofunctional polymerizable monomer or a polyfunctional polymerizable monomer is used. be able to.

(Inorganic fine powder)
In order to impart fluidity to the toner, a known inorganic fine powder may be externally added to the toner particles.

  The inorganic fine powder externally added to the toner particles preferably contains at least a silica fine powder. The number average particle size of primary particles of the silica fine powder is preferably 4 nm or more and 80 nm or less. When the number average particle diameter of the primary particles of the inorganic fine powder is within the above range, the fluidity of the toner is improved and the storage stability of the toner is also improved.

  In addition, the number average particle diameter of the primary particles of the inorganic fine powder is measured as follows.

  The inorganic fine powder on the surface of the toner particles is observed with a scanning electron microscope, the particle diameters of 100 inorganic fine powders in the visual field are measured, and the average value of the particle diameters is defined as the number average particle diameter of the primary particles. .

  In addition to fine silica powder, fine powder of titanium oxide, alumina or their double oxide can be used in combination. As the inorganic fine powder used together with the silica fine powder, titanium oxide is preferable.

  In addition, the inorganic fine powder may be hydrophobized.

  Examples of the treatment agent for the hydrophobic treatment of the inorganic fine powder include the following.

  Unmodified silicone varnish, various modified silicone varnishes, unmodified silicone oil, various modified silicone oils, silane compounds, silane coupling agents, other organosilicon compounds, and organotitanium compounds. These treatment agents may be used alone or in combination.

  Among these, inorganic fine powder treated with silicone oil is preferable. More preferably, the inorganic fine powder is hydrophobized inorganic fine powder treated with silicone oil, which is treated with silicone oil at the same time or after hydrophobizing the inorganic fine powder with a coupling agent. This is preferable because the triboelectric charge amount of the toner particles can be maintained high even under a high humidity environment, and the selective developability can be reduced.

[Dissolution suspension method]
Next, a second toner production method (dissolution suspension method) will be described.

  The second toner production method includes a granulation step in which a pigment dispersion is dispersed in an aqueous medium to produce pigment dispersion particles, and an organic solvent is removed from the obtained pigment dispersion particles. It has a solvent process.

  Specifically, a binder resin, a pigment, the aromatic oxycarboxylic acid represented by the above formula (1) and other materials as necessary are dissolved or dispersed in an organic solvent, and a toner composition is contained. A pigment dispersion is prepared. Next, the pigment dispersion is added to an aqueous medium to produce particles of the pigment dispersion. From the particles of the obtained pigment dispersion, the organic solvent is removed by heating or reducing the pressure, and then toner particles can be obtained through filtration, washing, and drying steps.

  Each manufacturing process will be specifically described below.

  First, in the granulation step, for example, an emulsified or dispersed liquid is obtained by emulsifying or dispersing a solution (oil phase) in which a toner composition containing a binder resin such as a polyester resin is dissolved or dispersed in a solvent. Prepare.

  In order to lower the viscosity of the oil phase, it is preferable to use a solvent that dissolves the binder resin. Thereby, the particle size distribution of the toner can be sharpened. Furthermore, since the solvent is easy to remove, the boiling point is preferably less than 100 ° C.

  Examples of such solvents include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, acetic acid. Examples include ethyl, methyl ethyl ketone, and methyl isobutyl ketone. Two or more kinds may be used in combination. Of these, aromatic solvents such as toluene and xylene, and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform and carbon tetrachloride are preferred. These solvents may be used alone or in combination of two or more.

  The usage-amount of a solvent is 300 mass parts or less normally with respect to 100 mass parts of polyester, 100 mass parts or less are preferable, and 25-70 mass parts is more preferable.

  As the aqueous medium, water, a solvent miscible with water, and a mixture of water can be used.

  Examples of solvents miscible with water include alcohols (methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.), and the like.

  The polyester resin and the other toner composition may be mixed when the oil phase is emulsified or dispersed in the aqueous medium, but the oil phase in which the entire toner composition is previously dissolved or dispersed in the solvent is added to the aqueous medium. Is preferably emulsified or dispersed. Examples of other toner compositions include pigments, aromatic oxycarboxylic acids represented by the above formula (1), waxes, charge control agents, binder resins other than the above polyester resins, and the like.

  In addition to the aromatic oxycarboxylic acid represented by the above formula (1), other materials such as the wax, the polar resin, and the charge control agent are added when dispersing the pigment in the suspension dissolution method. May be. Similarly to the suspension polymerization method described above, a conventionally known dispersion apparatus may be used as necessary in consideration of the viscosity and dispersion time of the dispersion.

When emulsifying or dispersing the oil phase in an aqueous medium, although not particularly limited, a low-speed shearing disperser, a high-speed shearing disperser, a friction disperser, a high-pressure jet disperser, an ultrasonic disperser, or the like is used. be able to. In order to make the particle size of the emulsified or dispersed liquid 2 to 20 μm, a high-speed shearing disperser is preferable. When the high-speed shearing disperser is used, the rotation speed is not particularly limited, but is usually 1 × 10 ^{3 to} 3 × 10 ⁴ rpm, and preferably 5 × 10 ³ to 2 × 10 ⁴ rpm. In addition, the dispersion time is not particularly limited, but is usually 0.1 to 5 minutes in the case of a batch method. The temperature at the time of dispersion is usually 0 to 150 ° C. (under pressure), and 40 to 98 ° C. is preferable because the pigment can be favorably dispersed.

  The usage-amount of an aqueous medium is 50-2000 mass parts normally with respect to 100 mass parts of solid content contained in an oil phase, and 100-1000 mass parts is preferable.

  In the present invention, the aqueous medium may contain a dispersant as required. Thereby, the oil phase can be stably emulsified or dispersed, and the particle size distribution of the toner can be sharpened.

  As the dispersant, a dispersant used in the suspension polymerization method or a conventionally known surfactant can be used.

  Next, in the solvent removal step, the solvent is removed from the emulsified or dispersed liquid by heating and / or reducing the pressure as necessary.

  Furthermore, the aging process which heats the emulsification or dispersion liquid from which a part of solvent was removed at the temperature of 40-60 degreeC may be provided, and the remaining solvent may be removed after an aging process.

  As described above, the dispersion obtained through the granulation step and the solvent removal step is subjected to filtration, centrifugation, and the like as necessary to obtain base particles.

  Furthermore, you may wash | clean and dry the obtained base particle as needed. Further, an inorganic fine powder may be externally added to the toner particles as in the suspension polymerization method.

  The present invention will be specifically described with reference to the following examples. Unless otherwise specified, all parts and% in the examples and comparative examples are based on mass.

[Production Example 1 of Pigment Dispersion]
-Styrene 100.00 parts by mass-Aromatic oxycarboxylic acid (1) represented by the following formula (1) 0.88 parts by mass

  Formula (1)

・ C. I. Pigment Red 31 16.67 parts by mass The above material is put into an attritor (manufactured by Mitsui Kinzoku Co., Ltd.) containing zirconia beads having a diameter of 20 mm, and the stirring blade is rotated at a rotation speed of 300 revolutions / minute, and stirred for 5 hours. A dispersion (A) was obtained.

[Production Examples 2-18 of Pigment Dispersion]
For Pigment Dispersion Production Examples 2 to 18, the pigment dispersion was produced except that the pigment type and addition amount, the aromatic oxycarboxylic acid type and addition amount, and the organic solvent type were changed as shown in Table 1. Pigment dispersions (B) to (K) and (a) to (g) were prepared in the same manner as in Example 1.

  In addition, the aromatic oxycarboxylic acid (2) and the aromatic oxycarboxylic acid (3) in Table 1 are compounds having the structure of the following formula.

  Aromatic oxycarboxylic acid (2)

  Aromatic oxycarboxylic acid (3)

[Toner Production Example 1]
A toner (A) was produced by a suspension polymerization method according to the following procedure.

  9 parts by mass of tricalcium phosphate and 11 parts by mass of 10% hydrochloric acid are added to 1300 parts by mass of ion-exchanged water heated to a temperature of 60 ° C., and TK-type homomixer (manufactured by Special Machine Industries) is used. The aqueous medium was prepared by stirring at 000 r / min.

Moreover, the following material was mixed at 100 r / min with the propeller-type stirring apparatus, and the liquid mixture was prepared.
Styrene 50.0 parts by mass n-butyl acrylate 50.0 parts by mass Pigment dispersion (A) 100.0 parts by mass Sulphonic acid group-containing resin (acrylic base FCA-1001-NS, manufactured by Fujikura Kasei)
1.5 parts by mass / polar resin (styrene-methyl methacrylate-methacrylic acid copolymer)
(Copolymerization ratio: styrene / methyl methacrylate / methacrylic acid = 95.85 / 2.50 / 1.65, Mp = 15800, Mw = 14000) 26.0 parts by mass / negative charge control agent (Bontron E-88, 1.5 parts by mass / hydrocarbon wax having a maximum endothermic peak temperature of 77 ° C. (HNP-51, manufactured by Nippon Seiwa Co., Ltd.)
16.0 parts by mass Thereafter, the mixture was heated to a temperature of 60 ° C., and then stirred at 9,000 r / min with a TK homomixer (manufactured by Special Machine Industries).

  In this, 4.0 parts by mass of a polymerization initiator 2,2'-azobis (2,4-dimethylvaleronitrile) was dissolved to prepare a polymerizable monomer composition. The polymerizable monomer composition was charged into the aqueous medium, and the mixture was granulated by stirring at 15,000 r / min for 10 minutes at a temperature of 60 ° C. using a TK homomixer.

  Thereafter, the mixture was transferred to a propeller type stirring device and reacted at a temperature of 70 ° C. for 5 hours while stirring at 100 r / min, and then heated to a temperature of 80 ° C. and further reacted for 5 hours to produce toner particles. After completion of the polymerization reaction, the slurry containing the particles was cooled, washed with 10 times the amount of water as the slurry, filtered and dried, and then the particle size was adjusted by classification to obtain toner particles.

With respect to 100 parts by mass of the toner particles, 2.0 parts by mass of hydrophobic silica fine powder that is triboelectrically charged to the same polarity (negative polarity) as the toner particles as inorganic fine powder is 3,000 r by a Henschel mixer (manufactured by Mitsui Miike). The toner (A) was obtained by mixing for 15 minutes at / min. The hydrophobic silica fine powder is hydrophobized with dimethyl silicone oil (20% by mass), and the number average particle diameter of the primary particles is 10 nm and the BET specific surface area is 170 m ² / g.

[Toner Production Examples 2 to 10]
In toner production examples 2 to 10, toners (B) to (J) were prepared by suspension polymerization as in toner production example 1 except that the type of the pigment dispersion was changed as shown in Table 2. Manufactured.

[Toner Production Example 11]
Toner (K) was produced by the dissolution suspension method according to the following procedure.

  First, in producing a toner by the dissolution suspension method, first, a prepolymer was produced by the following method.

In a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe,
-Bisphenol A ethylene oxide 2-mole adduct 682 parts by mass-Bisphenol A propylene oxide 2-mole adduct 81 parts by mass-Terephthalic acid 283 parts by mass-Trimellitic anhydride 22 parts by mass-Dibutyltin oxide 2 parts by mass under normal pressure And reacted at 230 ° C. for 8 hours. Subsequently, it was made to react under reduced pressure of 10mHg-15mHg for 5 hours, and the intermediate polyester was synthesize | combined. The obtained intermediate polyester has a number average molecular weight (Mn) of 2,100, a weight average molecular weight (Mw) of 9,600, a glass transition temperature (Tg) of 55 ° C., an acid value of 0.5, and a hydroxyl value of 49.

  Next, 411 parts by mass of the intermediate polyester, 89 parts by mass of isophorone diisocyanate, and 500 parts by mass of ethyl acetate are charged in a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, and reacted at 100 ° C. for 5 hours. To prepare a prepolymer.

  Next, an aqueous medium and a solution were adjusted according to the following procedure to prepare a toner.

  660 parts by weight of water and 25 parts by weight of 48.5% by weight sodium dodecyl diphenyl ether disulfonate aqueous solution are mixed and stirred, and stirred at 10,000 r / min using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). A medium was prepared.

The following materials were dissolved with a propeller type stirrer at 100 r / min to prepare a solution: Pigment dispersion (K) 100.0 parts by mass, 20.0 parts by mass of the prepolymer, polyester resin (bisphenol A / propylene oxide) adduct-terephthalic acid (Mp = 11,000, Tg = 66 ° C., acid value = 4.9 mgKOH / g, Mw / Mn = 3.1) 100.0 parts by mass / sulfonic acid group-containing resin (Acrylic base FCA-1001-NS, manufactured by Fujikura Kasei)
1.5 parts by mass / polar resin (styrene-methyl methacrylate-methacrylic acid copolymer)
(Copolymerization ratio: styrene / methyl methacrylate / methacrylic acid = 95.85 / 2.50 / 1.65, Mp = 15800, Mw = 14000) 26.0 parts by mass / negative charge control agent (Bontron E-88, 1.5 parts by mass / hydrocarbon wax having a maximum endothermic peak temperature of 77 ° C. (HNP-51, manufactured by Nippon Seiwa Co., Ltd.)
16.0 parts by mass Next, 150 parts by mass of the aqueous medium is put in a container, and stirred at a rotational speed of 12,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). The mixture was added and mixed for 10 minutes to prepare an emulsified slurry.

  Thereafter, 100 parts by mass of the emulsified slurry was charged into a flask equipped with a deaeration pipe, a stirrer and a thermometer, and the solvent was removed at 45 ° C. under reduced pressure at 30 ° C. for 12 hours while stirring at a stirring peripheral speed of 20 m / min. Aged for 4 hours to obtain a solvent-free slurry.

  After the solvent-removed slurry was filtered under reduced pressure, 300 parts by mass of ion-exchanged water was added to the obtained filter cake, mixed and redispersed (at 12,000 rpm for 10 minutes) with a TK homomixer, and then filtered. .

  The obtained filter cake was dried at 45 ° C. for 48 hours in a forward air dryer, and sieved toner particles were obtained with an opening of 75 μm mesh.

With respect to 100 parts by mass of the toner particles, 2.0 parts by mass of hydrophobic silica fine powder that is triboelectrically charged to the same polarity (negative polarity) as the toner particles as inorganic fine powder is 3,000 r by a Henschel mixer (manufactured by Mitsui Miike). The toner (K) was obtained by mixing for 15 minutes at / min. The hydrophobic silica fine powder is hydrophobized with dimethyl silicone oil (20% by mass), and the number average particle diameter of the primary particles is 10 nm and the BET specific surface area is 170 m ² / g.

[Toner Production Examples 12 to 16]
In Toner Production Examples 12 to 16, toners (a) to (e) were produced by suspension polymerization in the same manner as in Toner Production Example 1 except that the types of pigment dispersions shown in Table 2 were changed. .

[Toner Production Examples 17 and 18]
In toner production examples 17 and 18, toners (f) to (g) were produced by the dissolution suspension method in the same manner as in toner production example 11 except that the types of pigment dispersions shown in Table 2 were changed. .

<Examples 1-1 to 1-11 and Comparative Examples 1-1 to 1-7>
The pigment dispersions (A) to (K) and (a) to (g) prepared as described above were evaluated using the following evaluation methods. The obtained evaluation results are shown in Table 3.

(Evaluation of pigment dispersion)
[Gloss value of coating surface]
The pigment dispersion is sampled when the rotation time by an attritor at the time of producing the pigment dispersion is 1 hour, 3 hours, and 5 hours, and the developed paper “Super Art Paper (Kanafuji) using a bar coater (No. 10)” ) ”(Manufactured by Seven Dow) and dried. The gloss of the coating surface after drying was measured with a gloss meter “PG-3D, optical sensor; 75 ° -75 °” (manufactured by Nippon Denshoku Industries Co., Ltd.). The higher the gloss value, the better the pigment dispersion.

[State of pigment dispersion after standing]
The obtained pigment dispersion was put in a 100 cc glass bottle, and the state of the pigment dispersion after standing for one week in an environment of 25 ° C. was visually confirmed. By this evaluation, the stability of the pigment dispersion can be confirmed.
A: No change.
B: Although a slight solvent layer exists in the upper layer, it returns to its original state when shaken.
C: The pigment is completely settled and does not return to the original state even when shaken.

<Examples 2-1 to 2-11 and Comparative Examples 2-1 to 2-7>
The toners (A) to (K) and (a) to (g) produced as described above were evaluated using the following evaluation methods. The obtained evaluation results are shown in Table 4.

(Evaluation of toner)
[Pigment dispersion in toner]
Any five toners were selected, and a TEM image of the toner cross section was taken. The obtained image was visually observed, and the pigment dispersion state in the toner was evaluated according to the following criteria.
A: 0 pigment aggregates.
B: 1 to 4 pigment aggregates.
C: 5 to 9 pigment aggregates.
D: Aggregates of 10 or more pigment aggregates or 0.5 μm or more are generated.

[Toner coloring power]
In the developing device (Satera LBP5300; manufactured by Canon Inc.) of the one-component contact developing system shown in FIG. In addition, Xerox 4200 (Xerox Co., Ltd., 75 g / m ² paper) was used as the transfer paper. The developing device shown in FIG. 1 was mounted on the unit 104a shown in FIG. 2 under a normal temperature and normal humidity (temperature 23.5 ° C., humidity 60% RH) environment. The process speed was set to 150 mm / s in the magenta single color mode. A solid image was printed on the transfer paper so that the applied amount of toner was 0.40 mg / cm ^2, and the image density of the solid image was measured using “Mugbes Reflectometer RD918” (manufactured by Magbes).

10 Latent image carrier (photosensitive drum)
DESCRIPTION OF SYMBOLS 11 Contact charging member 12 Power supply 13 Developing unit 14 Toner carrier 15 Toner supply roller 15a Toner supply roller shaft 16 Restriction member 17 Nonmagnetic toner 23 Developer container 24 Restriction member support sheet metal 25 Toner stirring member 26 Toner blowing prevention sheet 27 Power supply 29 Charging roller 30 Suppressing member 101a-d Photosensitive drum 102a-d Primary charging means 103a-d Scanner 104a-d Developing section 106a-d Cleaning means 108b Paper feed roller 108c Registration roller 109a Electrostatic adsorption conveyance belt 109b Driving roller 109c Fixed roller 109d Tension roller 109e Fixed roller 110 Fixing device 110c Discharge roller 110d Static elimination sheet 111 Fixing device frame 111a Paper feed guide 112 Fixing device maintenance door 112a Fixing Fixing members 113 output tray 115, 116 discharge rollers 117 copies feed guide S recording medium

Claims (12)

A pigment dispersion method of mixing an organic solvent, a pigment and a pigment dispersant, and dispersing the pigment in the organic solvent by stirring,
The pigment is C.I. I. Pigment Red 31, C.I. I. Pigment Red 150, C.I. I. Pigment Red 176 and C.I. I. At least one pigment selected from the group consisting of Pigment Red 269,
The pigment dispersing method, wherein the pigment dispersant is an aromatic oxycarboxylic acid represented by the following formula (1).
Formula (1)
  The mass ratio of the pigment to the aromatic oxycarboxylic acid (the mass of the pigment: the mass of the aromatic oxycarboxylic acid) is 99.0: 1.0 to 70.0: 30.0. Item 2. The pigment dispersion method according to Item 1.   The pigment dispersion method according to claim 1 or 2, wherein the organic solvent is an aromatic organic solvent.   The pigment dispersion method according to claim 3, wherein the aromatic organic solvent is styrene.   A method for producing a toner, comprising: a pigment dispersion step of obtaining a pigment dispersion by dispersing a pigment in an organic solvent by the pigment dispersion method according to claim 1. The organic solvent has a polymerizable monomer whose main component is styrene,
A granulating step of dispersing the pigment dispersion in an aqueous medium to produce particles of the pigment dispersion; and
6. The method for producing a toner according to claim 5, further comprising a polymerization step of polymerizing the polymerizable monomer in the particles of the obtained pigment dispersion. A step of dissolving a binder resin in the pigment dispersion ;
A granulation step of dispersing the pigment dispersion in which the binder resin is dissolved in an aqueous medium to produce particles of the pigment dispersion; and
The toner production method according to claim 5, further comprising a solvent removal step of removing the organic solvent from the particles of the obtained pigment dispersion. A pigment dispersant for dispersing a pigment in an organic solvent,
The pigment is C.I. I. Pigment Red 31, C.I. I. Pigment Red 150, C.I. I. Pigment Red 176 and C.I. I. At least one pigment selected from the group consisting of Pigment Red 269,
The pigment dispersant is an aromatic oxycarboxylic acid represented by the following formula (1).
Formula (1)
An organic solvent , a pigment dispersion having a pigment dispersant and a pigment dispersed in the organic solvent ,
The pigment is C.I. I. Pigment Red 31, C.I. I. Pigment Red 150, C.I. I. Pigment Red 176 and C.I. I. At least one pigment selected from the group consisting of Pigment Red 269,
The pigment dispersion is characterized in that the pigment dispersant is an aromatic oxycarboxylic acid represented by the following formula (1).
Formula (1)
  The mass ratio of the pigment to the aromatic oxycarboxylic acid (the mass of the pigment: the mass of the aromatic oxycarboxylic acid) is 99.0: 1.0 to 70.0: 30.0. Item 10. The pigment dispersion according to Item 9.   The pigment dispersion liquid according to claim 9 or 10, wherein the organic solvent is an aromatic organic solvent.   The pigment dispersion liquid according to claim 11, wherein the aromatic organic solvent is styrene.