WO2023127815A1

WO2023127815A1 - Toner for electrostatic image development

Info

Publication number: WO2023127815A1
Application number: PCT/JP2022/047963
Authority: WO
Inventors: 尊千葉
Original assignee: 日本ゼオン株式会社
Priority date: 2021-12-28
Filing date: 2022-12-26
Publication date: 2023-07-06

Abstract

Provided is a toner for electrostatic image development that contains coloring resin particles containing a binder resin, a coloring agent, an electrostatic charge control agent, and a crystalline material. When reflection electron images of cross sections of the coloring resin particles are observed using a scanning electron microscope, the total area ratio of domains of the crystalline material on the cross sections of the coloring resin particle is 10-30%, and the average number of the domains of the crystalline material that are present on the cross sections of the coloring resin particles is 5-40 per particle.

Description

Toner for electrostatic charge image development

The present invention relates to an electrostatic charge image developing toner used for developing electrostatic latent images in electrophotography, electrostatic recording, electrostatic printing, and the like.

An image forming apparatus such as an electrophotographic apparatus, an electrostatic recording apparatus, and an electrostatic printing apparatus forms a desired image by developing an electrostatic latent image formed on a photoreceptor with a toner for developing an electrostatic image. This method is widely practiced and applied to copiers, printers, facsimiles, and multi-function machines.

For example, in an electrophotographic apparatus using electrophotography, the surface of a photoreceptor made of a photoconductive material is generally uniformly charged by various means, and then an electrostatic latent image is formed on the photoreceptor. Next, the electrostatic latent image is developed using toner (development process), and if necessary, the toner image is transferred to a recording material such as paper (transfer process), after which the toner is fixed to the recording material by heating or the like. (fixing step) to obtain a printed matter.

Among the above image forming processes, in the fixing process, it is usually necessary to heat the fixing roll to 150°C or higher during fixing, and a large amount of electric power is consumed as an energy source. On the other hand, in recent years, with the increasing demand for the image forming apparatus to reduce energy consumption and increase printing speed, toners capable of maintaining a high fixing rate even at low fixing temperatures (toners with excellent low-temperature fixing properties) have been developed. design is required.

For example, Patent Document 1 discloses a toner containing toner particles containing a binder resin and a crystalline material as a technique for achieving excellent low-temperature fixability and simultaneously suppressing gloss unevenness and edge high-temperature offset. In the powder dynamic viscoelasticity measurement, the onset temperature T (A) of the storage elastic modulus E′ obtained when the temperature is raised at 20 ° C./min and when the temperature is raised at 5 ° C./min and the onset temperature T (B) of the storage modulus E' obtained in , satisfies the relationship T (A) - T (B) ≤ 3.0 ° C., and the peak of the maximum endothermic peak by differential scanning calorimetry A toner is proposed in which the temperature is 50.0 to 90.0° C. and the content of tetrahydrofuran-insoluble matter in the binder resin is in the range of 15 to 60 mass %.

Japanese Patent Application Laid-Open No. 2021-5050

In recent years, there has been an increasing demand for further reductions in energy consumption and further speeding up of printing. Needs improvement. According to the study of the present inventors, it was found that the toner described in Patent Document 1 requires further improvement.
The present invention has been made in view of such actual circumstances, and an object of the present invention is to provide excellent low-temperature fixability, excellent hot-offset resistance, fine-line reproducibility and blade cleaning performance in a well-balanced manner, and to provide a toner after standing at a high temperature. It is an object of the present invention to provide a method for producing a toner for developing an electrostatic charge image in which the occurrence of toner ejection is suppressed.

In order to achieve the above objects, the inventors of the present invention conducted investigations and found that a toner for developing an electrostatic charge image containing colored resin particles containing a binder resin, a coloring agent, a charge control agent, and a crystalline material has an electrostatic charge image developing toner. The colored resin particles constituting the toner for developing a charge image have a specific fine structure. found that the above object can be achieved by setting the total area ratio of the domains of the crystalline material and the number of domains of the crystalline material in the cross section of the colored resin particles to specific ranges, and completed the present invention. I came to let you.

That is, according to the present invention, there is provided a toner for electrostatic charge image development containing colored resin particles containing a binder resin, a coloring agent, a charge control agent, and a crystalline material,
When the cross section of the colored resin particles is observed with a backscattered electron image of a scanning electron microscope, the total area ratio of the domains of the crystalline material in the cross section of the colored resin particles is 10 to 30%, and the colored resin Provided is an electrostatic charge image developing toner in which the average number of domains of the crystalline material present in the cross section of the particles is in the range of 10 to 40 per particle.

In the electrostatic charge image developing toner of the present invention, the average circularity of the domains of the crystalline material in the cross section of the colored resin particles when the cross section of the colored resin particles is observed with a backscattered electron image of a scanning electron microscope. is preferably 0.50 or less.
In the toner for developing an electrostatic charge image of the present invention, when the cross section of the colored resin particles is observed with a backscattered electron image of a scanning electron microscope, the length of the domains of the crystalline material in the cross section of the colored resin particles is equal to the length of the domains of the crystalline material. The average diameter ratio is preferably 0.60 or less.
In the electrostatic charge image developing toner of the present invention, the content of the crystalline material is preferably 5.0 to 40.0 parts by mass with respect to 100 parts by mass of the binder resin.
In the electrostatic charge image developing toner of the present invention, the crystalline material is preferably an ester wax having a number average molecular weight (Mn) of 500-1550.

In the electrostatic charge image developing toner of the present invention, it is preferable that the colored resin particles further contain an additive having a polydiene structure.
In the toner for electrostatic charge image development of the present invention, it is preferable that the content of the additive having a polydiene structure is 0.5 to 20 parts by mass with respect to 100 parts by mass of the binder resin.
In the electrostatic charge image developing toner of the present invention, the binder resin is preferably a styrene-(meth)acrylate copolymer.
The electrostatic charge image developing toner of the present invention is preferably a positively charged toner.
The electrostatic charge image developing toner of the present invention is preferably prepared by a pulverization method or a suspension polymerization method.

According to the present invention, an electrostatic charge image developing toner having excellent low-temperature fixability, excellent hot offset resistance, fine line reproducibility, and blade cleaning performance in a well-balanced manner, and suppressing the occurrence of toner ejection after being left at high temperature. Toner can be manufactured.

FIG. 1 is a cross-sectional photograph of colored resin particles obtained by a backscattered electron image of a scanning electron microscope (FE-SEM) in Example 6. FIG.

The toner for electrostatic charge image development of the present invention (hereinafter sometimes simply referred to as "toner") is an electrostatic charge containing colored resin particles containing a binder resin, a colorant, a charge control agent, and a crystalline material. A toner for developing a charge image,
When the cross section of the colored resin particles is observed with a backscattered electron image of a scanning electron microscope, the total area ratio of the domains of the crystalline material in the cross section of the colored resin particles is 10 to 30%, and the colored resin The average number of domains of the crystalline material present in the cross section of the grain is in the range of 10 to 40 per grain.

First, the colored resin particles constituting the toner of the present invention will be described.
The colored resin particles constituting the toner of the present invention can be produced, for example, by a dry method such as a pulverization method, or a wet method such as an emulsion polymerization aggregation method, a dispersion polymerization method, a suspension polymerization method, and a dissolution suspension method. . As the colored resin particles constituting the toner of the present invention, those obtained by a pulverization method, which is an example of a dry method, can be preferably used.
A method for producing colored resin particles constituting the toner of the present invention by a pulverization method, which is an example of a dry method, will be described below.

In the pulverization method, first, a binder resin, a coloring agent, a charge control agent, a crystalline material, and other additives added as necessary are kneaded while being heated using a mixer to obtain a powder. After coarsely pulverizing and finely pulverizing the resulting kneaded material, the pulverized material of the colored resin particles is obtained by classifying the kneaded material into a desired particle size with a classifier.

The binder resin is not particularly limited. styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyethylene resin, polypropylene resin, and the like. The binder resin may be used singly or in combination of two or more. Among these, styrene-(meth)acrylic acid ester copolymers and polyester resins are preferred, and styrene-(meth)acrylic acid ester copolymers are more preferred, from the viewpoint of being able to further improve low-temperature fixability. Styrene-acrylate copolymers are more preferred.

The (meth)acrylic acid ester constituting the styrene-(meth)acrylic acid ester copolymer includes methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and dimethylamino acrylate. Ethyl, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, dimethylaminoethyl methacrylate, and the like. These (meth)acrylic acid esters may be used alone or in combination of two or more. Among these, ethyl acrylate, propyl acrylate, and butyl acrylate are preferred, and n-butyl acrylate is more preferred.

The content of styrene units in the styrene-(meth)acrylic acid ester copolymer is preferably 60 to 90% by mass, more preferably 70 to 90% by mass, and still more preferably 80 to 90% by mass. The content of the (meth)acrylic acid ester monomer units is preferably 10 to 40% by mass, more preferably 10 to 30% by mass, and still more preferably 10 to 20% by mass.

Also, the glass transition temperature of the binder resin is preferably 40 to 80°C, more preferably 45 to 70°C, and even more preferably 50 to 60°C. By setting the glass transition temperature within the above range, the low-temperature fixability can be enhanced more appropriately. The glass transition temperature of the binder resin can be determined according to ASTM D3418-82, for example.

As the colorant, for example, in the case of producing a color toner (usually, four kinds of toners of black toner, cyan toner, yellow toner, and magenta toner are used), a black colorant, a cyan colorant, a yellow colorant, Each magenta colorant can be used.

As the black colorant, for example, pigments and dyes such as carbon black, titanium black, and magnetic powders such as zinc iron oxide and nickel iron oxide can be used.

As cyan colorants, for example, copper phthalocyanine pigments, derivatives thereof, and compounds such as anthraquinone pigments and dyes are used. Specifically, C.I. I. Pigment Blue 2, 3, 6, 15, 15:1, 15:2, 15:3, 15:4, 16, 17:1, 60 and the like.

Examples of yellow colorants include azo pigments such as monoazo pigments and disazo pigments, compounds such as condensed polycyclic pigments and dyes. Specifically, C.I. I. Pigment Yellow 3, 12, 13, 14, 15, 17, 62, 65, 73, 74, 83, 93, 97, 120, 138, 151, 155, 180, 181, 185, 186, 214, 219, C.I. I. Solvent Yellow 98, 162 and the like.

Examples of magenta colorants include azo pigments such as monoazo pigments and disazo pigments, compounds such as condensed polycyclic pigments and dyes. Specifically, C.I. I. Pigment Red 31, 48, 57: 1, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 149, 150, 163, 170 , 184, 185, 187, 202, 206, 207, 209, 238, 269, 251, C.I. I. Solvent Violet 31, 47, 59 and C.I. I. Pigment Violet 19 and the like.

The colorants may be used alone or in combination of two or more. The amount of the colorant used is preferably 1 to 15 parts by mass, more preferably 1 to 15 parts by mass, based on 100 parts by mass of the binder resin. is 1 to 10 parts by mass, more preferably 2 to 8 parts by mass.

The charge control agent is not particularly limited as long as it is generally used as a charge control agent for toner. stability) can be imparted to the toner particles, thereby improving the dispersibility of the colorant. is more preferred. That is, the toner of the present invention is more preferably positively charged toner.

Examples of positive charge control agents include nigrosine dyes, quaternary ammonium salts, triaminotriphenylmethane compounds and imidazole compounds, and polyamine resins and copolymers containing quaternary ammonium groups as charge control resins preferably used. , and quaternary ammonium base-containing copolymers.

Examples of negative charge control agents include azo dyes containing metals such as Cr, Co, Al, and Fe, metal salicylate compounds and metal alkylsalicylate compounds, and preferably used charge control resins containing sulfonic acid groups. Examples thereof include copolymers, sulfonic acid group-containing copolymers, carboxylic acid group-containing copolymers, and carboxylic acid group-containing copolymers.

The weight-average molecular weight (Mw) of the charge control resin is within the range of 5,000 to 30,000, preferably 8,000, as a polystyrene conversion value measured by gel permeation chromatography (GPC) using tetrahydrofuran. 000 to 25,000, more preferably 10,000 to 20,000.

Further, the copolymerization ratio (functional group amount) of the monomer having a functional group such as a quaternary ammonium base or a sulfonate base in the charge control resin is preferably in the range of 0.5 to 12% by mass, and more It is preferably within the range of 1.0 to 6% by mass, more preferably within the range of 1.5 to 5% by mass.

The content of the charge control agent is preferably 0.01 to 20 parts by mass, more preferably 0.03 to 10 parts by mass, and still more preferably 0.03 to 8 parts by mass with respect to 100 parts by mass of the binder resin. be. By setting the amount of the charge control agent to be added within the above range, the dispersibility of the colorant can be increased appropriately while effectively suppressing the occurrence of fogging and the occurrence of printing stains.

Examples of crystalline materials include materials that act as release agents for toners and materials that impart an effect of improving fixability, such as crystalline polyester resins and ester waxes. In the toner of the present invention, the crystalline material exists in a state in which at least a portion thereof forms a domain structure in the colored resin particles. A domain structure formed of a crystalline material will be described later.

Examples of crystalline polyester resins include condensation polymerization products of aliphatic diols and aliphatic dicarboxylic acids. Examples of crystalline polyester resins include aliphatic diols having 2 to 12 carbon atoms and aliphatic It is preferably a polycondensation product with group dicarboxylic acid.

Examples of aliphatic diols having 2 to 12 carbon atoms include 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1 ,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol and the like. These may be used alone, or two or more of them may be mixed and used.

Examples of aliphatic dicarboxylic acids having 2 to 12 carbon atoms include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, and lower alkyl esters and acid anhydrides of these aliphatic dicarboxylic acids. These may be used alone, or two or more of them may be mixed and used.

An aromatic dicarboxylic acid can also be used together with an aliphatic dicarboxylic acid having 2 to 12 carbon atoms or in place of an aliphatic dicarboxylic acid having 2 to 12 carbon atoms. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid and 4,4'-biphenyldicarboxylic acid.

A crystalline polyester resin can be produced, for example, by a general polyester polymerization method in which a dicarboxylic acid component and a diol component are reacted. Polymerization methods include, for example, a direct polycondensation method and a transesterification method.

Although the ester wax is not particularly limited, ester waxes having a number average molecular weight (Mn) of 500 to 1,550 are preferable, and fatty acid ester compounds having a number average molecular weight (Mn) of 500 to 1,550 are preferable. The fatty acid ester compound is preferably a product obtained by an ester reaction between a monohydric alcohol and/or polyhydric alcohol and a saturated fatty acid and/or unsaturated fatty acid.

Specific examples of monohydric alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 1-hexanol, octanol, 2-ethyl-1-hexanol, nonyl alcohol. , lauryl alcohol, cetyl alcohol, stearyl alcohol, and behenyl alcohol; monovalent unsaturated aliphatic alcohols such as allyl alcohol, methallyl alcohol, crotyl alcohol, and oleyl alcohol; monohydric aromatic alcohols such as phenol, phenylmethanol (benzyl alcohol), methylphenol (cresol), p-ethylphenol, dimethylphenol (xylenol), nonylphenol, dodecylphenol, phenylphenol, and naphthol ; and the like.

Specific examples of polyhydric alcohols include divalent saturated aliphatic alcohols such as ethylene glycol and propylene glycol; divalent aromatic alcohols such as catechol and hydroquinone; valence or higher saturated fatty alcohols; and the like.

Among these monohydric alcohols and polyhydric alcohols, monohydric to tetrahydric saturated aliphatic alcohols are preferred, behenyl alcohol and pentaerythritol are more preferred, and behenyl alcohol is particularly preferred.

The fatty acid used as the raw material for the fatty acid ester compound preferably has 12 to 22 carbon atoms, more preferably saturated and/or unsaturated fatty acids having 14 to 18 carbon atoms. Among these, saturated fatty acids having the above-mentioned number of carbon atoms are particularly preferred, since a fatty acid ester compound having a number average molecular weight (Mn) of 500 to 1,550 can be easily obtained.

Specific examples of saturated fatty acids having the above carbon number are not particularly limited, but lauric acid (12 carbon atoms), myristic acid (14 carbon atoms), pentadecylic acid (15 carbon atoms), palmitic acid (16 carbon atoms), margarine acid (17 carbon atoms), stearic acid (18 carbon atoms), arachidic acid (20 carbon atoms), behenic acid (22 carbon atoms), and the like. Among these saturated fatty acids, stearic acid (18 carbon atoms), arachidic acid (20 carbon atoms), and behenic acid (22 carbon atoms) are preferred, and stearic acid (18 carbon atoms) is more preferred.

Specific examples of unsaturated fatty acids include, but are not limited to, the following compounds.
Palmitoleic acid ( _CH3 ( _CH2 ) _5CH =CH( _CH2 ) _7COOH )
Oleic acid ( _CH3 ( _CH2 ) _7CH =CH( _CH2 ) _7COOH )
vaccenic acid ( _CH3 ( _CH2 ) _5CH =CH( _CH2 ) _9COOH )
Linoleic acid ( _CH3 ( _CH2 ) ₃ ( _CH2CH =CH) ₂ ( _CH2 ) _7COOH )
(9,12,15)-linolenic acid (CH ₃ (CH ₂ CH═CH) ₃ (CH ₂ ) ₇ COOH)
(6,9,12)-linolenic acid (CH ₃ (CH ₂ ) ₃ (CH ₂ CH═CH) ₃ (CH ₂ ) ₄ COOH)
Eleostearic acid ( _CH3 ( _CH2 ) ₃ (CH=CH) ₃ ( _CH2 ) _7COOH )
Arachidonic acid ( _CH3 ( _CH2 ) ₃ ( _CH2CH =CH) ₄ ( _CH2 ) _3COOH )

The above saturated fatty acid and/or unsaturated fatty acid may be used singly or in combination of two or more.

A fatty acid ester compound as described above can be produced according to a conventional method. A method for producing such a fatty acid ester compound includes, for example, a method of performing an ester reaction using a monohydric alcohol and/or polyhydric alcohol and a saturated fatty acid and/or unsaturated fatty acid. In addition, as the fatty acid ester compound, it is possible to use a commercially available fatty acid ester compound. Examples of commercially available fatty acid ester compounds include "WEP2", "WEP3", "WEP4", "WEP5", and "WE6" manufactured by NOF Corporation. "WE11" (these are trade names) and the like.

The number average molecular weight (Mn) of the fatty acid ester compound is preferably 500-1550, more preferably 550-1200, still more preferably 550-1100. The number average molecular weight (Mn) of the fatty acid ester compound can be measured, for example, by gel permeation chromatography (GPC) using tetrahydrofuran in terms of polystyrene.

In addition, as the crystalline material, other crystalline materials may be used instead of the crystalline polyester resin and ester wax described above, or together with the crystalline polyester resin or ester wax. Materials include, for example, low molecular weight polyolefin waxes and modified waxes thereof; natural plant waxes such as jojoba; petroleum waxes such as paraffin; mineral waxes such as ozokerite; synthetic waxes such as Fischer-Tropsch wax; polyhydric alcohol ester; These may be used alone or in combination of two or more.

The melting point of the crystalline material is preferably 50 to 90° C., more preferably 60 to 90° C., still more preferably 65 to 80° C., particularly preferably 68 to 80° C., from the viewpoint of further enhancing the low-temperature fixability of the resulting toner. °C, most preferably 70-80 °C.

The content of the crystalline material is preferably 5.0 to 40.0 parts by mass, more preferably 10 to 35 parts by mass, still more preferably 15 to 30 parts by mass, with respect to 100 parts by mass of the binder resin. be. By setting the content of the crystalline material within the above range, it is possible to improve the low-temperature fixability while making the particle size distribution of the obtained toner relatively uniform.

In addition, the colored resin particles may further contain an additive having a polydiene structure. By using such an additive having a polydiene structure, it is possible to increase the dispersibility of the crystalline material in the colored resin particles due to the compatibility with the crystalline material possessed by the additive having a polydiene structure. , the domain structure of the crystalline material, which will be described later, can be more preferably formed in the colored resin particles.

The additive having a polydiene structure is not particularly limited, but for example, a conjugated diene-aromatic vinyl-based polymer, which is a polymer having a structural unit derived from a conjugated diene compound and a structural unit derived from an aromatic vinyl compound Thermoplastic elastomers; conjugated diene elastomers such as polybutadiene rubber and polyisoprene rubber; Unhydrogenated conjugated diene-aromatic vinyl thermoplastic elastomers are particularly preferred.

Conjugated diene-aromatic vinyl thermoplastic elastomers include random, block, and graft copolymers of conjugated diene monomers, aromatic vinyl monomers, and optionally other monomers that can be copolymerized therewith. and the like, and hydrogenated products of such copolymers.

Such a conjugated diene-aromatic vinyl thermoplastic elastomer is not particularly limited, but from the viewpoint of further improving the low-temperature fixability of the toner, it contains at least one aromatic vinyl polymer block and at least one conjugated diene polymer. Block copolymers containing blocks can be suitably used.

Hereinafter, block copolymers containing at least one aromatic vinyl polymer block and at least one conjugated diene polymer block (hereinafter simply referred to as "block copolymer (sometimes referred to as “union”) will be described. The block copolymer used in the present invention comprises an aromatic vinyl polymer block obtained by polymerizing an aromatic vinyl monomer and a conjugated diene polymer block obtained by polymerizing a conjugated diene monomer. It contains at least one.

The aromatic vinyl monomer is not particularly limited as long as it is an aromatic vinyl compound. Styrene, 4-ethylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, 2-chlorostyrene, 3-chlorostyrene, 4 -chlorostyrene, 4-bromostyrene, 2-methyl-4,6-dichlorostyrene, 2,4-dibromostyrene, vinylnaphthalene and the like. Among these, it is preferable to use styrene. These aromatic vinyl monomers may be used alone or in combination of two or more in each aromatic vinyl polymer block. Further, when the block copolymer has a plurality of aromatic vinyl polymer blocks, each aromatic vinyl polymer block may be composed of the same aromatic vinyl monomer units, or may be composed of different aromatic vinyl monomer units. It may be composed of vinyl monomer units.

The aromatic vinyl polymer block may contain other monomer units as long as the aromatic vinyl monomer unit is the main repeating unit. Other monomers that can be used in the aromatic vinyl polymer block include conjugated diene monomers such as 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), α,β-unsaturated Examples include nitrile monomers, unsaturated carboxylic acid or acid anhydride monomers, unsaturated carboxylic acid ester monomers, non-conjugated diene monomers, and the like. The content of monomer units other than aromatic vinyl monomer units in the aromatic vinyl polymer block is preferably 20% by mass or less, more preferably 10% by mass or less, and is substantially zero. % by weight is particularly preferred.

The conjugated diene monomer is not particularly limited as long as it is a conjugated diene compound. 3-pentadiene, 1,3-hexadiene, and the like. Among these, 1,3-butadiene and/or isoprene are preferably used, and isoprene is particularly preferably used, from the viewpoint of a high effect of improving low-temperature fixability. These conjugated diene monomers may be used alone or in combination of two or more in each conjugated diene polymer block. Further, when the block copolymer has a plurality of conjugated diene polymer blocks, each conjugated diene polymer block may be composed of the same conjugated diene monomer units, or may be composed of different conjugated diene monomer units. It may be composed of units. Furthermore, a hydrogenation reaction may be performed on a part of the unsaturated bonds of each conjugated diene polymer block.

The conjugated diene polymer block may contain other monomer units as long as the conjugated diene monomer unit is the main repeating unit. Other monomers that can be used in the conjugated diene polymer block include aromatic vinyl monomers such as styrene, α-methylstyrene, α,β-unsaturated nitrile monomers, unsaturated carboxylic acid monomers. , unsaturated carboxylic acid anhydride monomers, unsaturated carboxylic acid ester monomers, and non-conjugated diene monomers. The content of monomer units other than conjugated diene monomer units in the conjugated diene polymer block is preferably 20% by mass or less, more preferably 10% by mass or less, and substantially 0% by mass. is particularly preferred.

The vinyl bond content of the conjugated diene polymer block (ratio of 1,2-vinyl bond units and 3,4-vinyl bond units to all conjugated diene monomer units in the conjugated diene polymer block) is not particularly limited. However, it is preferably 1 to 20 mol %, more preferably 2 to 15 mol %, and particularly preferably 3 to 10 mol %.

As long as the block copolymer contains at least one aromatic vinyl polymer block and at least one conjugated diene polymer block, the number of each polymer block and the form of bonding thereof are not particularly limited. Specific examples of block copolymers include the following. In the following specific examples, Ar represents an aromatic vinyl polymer block, D represents a conjugated diene polymer block, X represents a residue of a coupling agent, and n represents an integer of 2 or greater.
(a) an aromatic vinyl-conjugated diene block copolymer represented as Ar-D; (b) an aromatic vinyl-conjugated diene- represented as Ar-D-Ar and/or (Ar-D)nX- Aromatic vinyl block copolymers (c) conjugated diene-aromatic vinyl-conjugated diene block copolymers represented as D-Ar-D and/or (D-Ar)nX (d) Ar-D- an aromatic vinyl-conjugated diene-aromatic vinyl-conjugated diene block copolymer represented as Ar-D;
(e) A composition of a block copolymer obtained by arbitrarily combining two or more of the above (a) to (d)

As the block copolymer, it is preferable to use one containing at least the aromatic vinyl-conjugated diene block copolymer represented by (a) Ar-D, and the aromatic copolymer represented by (a) Ar-D at least a vinyl-conjugated diene block copolymer and (b) an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer represented as Ar—D—Ar and/or (Ar—D)n—X It is more preferable to use those containing. The aromatic vinyl-conjugated diene block copolymer represented by Ar-D in the conjugated diene-aromatic vinyl thermoplastic elastomer (that is, the aromatic vinyl polymer block and the aromatic vinyl polymer can be copolymerized The content of the diblock copolymer consisting of a block of a polymer) is preferably 40% by mass (% by weight) or more, preferably 50% by mass or more, and more preferably 55% by mass or more. , more preferably 60% by mass or more. The upper limit is not particularly limited, but is preferably 98% by mass or less, more preferably 95% by mass or less, and still more preferably 90% by mass or less. The aromatic vinyl-conjugated diene block copolymer represented by Ar-D in the conjugated diene-aromatic vinyl thermoplastic elastomer (that is, the aromatic vinyl polymer block and the aromatic vinyl polymer can be copolymerized By setting the content of the diblock copolymer to 40% by mass or more, the dispersibility in the colored resin particles and the compatibility with the crystalline material can be further enhanced.

The weight-average molecular weight (Mw (Ar)) of the aromatic vinyl polymer block Ar in the aromatic vinyl-conjugated diene block copolymer represented by Ar-D is not particularly limited, but is preferably 10,000 to 50,000, or more. The weight average molecular weight (Mw(D)) of the conjugated diene polymer block D is not particularly limited, but is preferably 50000 to 200000, more preferably 60000 to 150000, and even more preferably 70000. ~100000.

Also, in the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer represented as Ar-D-Ar and/or (Ar-D)nX, the weight average molecular weight of the aromatic vinyl polymer block Ar ( Mw (Ar)) is not particularly limited, but is preferably 20,000 to 70,000, more preferably 25,000 to 50,000. The weight average molecular weight (Mw (D)) of the conjugated diene polymer block D is not particularly limited, It is preferably 100,000 to 300,000, more preferably 120,000 to 250,000, even more preferably 150,000 to 200,000.
All of the above weight average molecular weights are polystyrene equivalent values measured by gel permeation chromatography (GPC) using tetrahydrofuran.

The content ratio of the aromatic vinyl monomer units to the total monomer units in the block copolymer is preferably 10 to 30% by mass, more preferably 12 to 25% by mass, and 15 to 25% by mass. % by mass is more preferred. By setting the content of the aromatic vinyl monomer unit within the above range, the dispersibility in the colored resin particles and the compatibility with the crystalline material can be further enhanced.

The content of aromatic vinyl monomer units in the block copolymer is such that all polymer components constituting the block copolymer are composed only of aromatic vinyl monomer units and conjugated diene monomer units. If Rubber Chem. Technol. , 45, 1295 (1972), the block copolymer is ozonolyzed and then reduced with lithium aluminum hydride to decompose the conjugated diene monomer unit portion and produce the aromatic vinyl monomer. Since only the unit portion can be taken out, the total aromatic vinyl monomer unit content can be easily measured.

Further, the weight average molecular weight (Mw) of the aromatic vinyl monomer unit in the block copolymer is not particularly limited, but is a polystyrene equivalent value measured by gel permeation chromatography (GPC) using tetrahydrofuran, It is preferably 10,000 to 50,000, more preferably 20,000 to 40,000. The weight average molecular weight (Mw) of the conjugated diene monomer unit in the block copolymer is not particularly limited, but is preferably 50,000 to 200,000, more preferably 60,000 to 180,000.

The melt index (MI) of the block copolymer is not particularly limited, but as a value measured according to ASTM D-1238 (G conditions, 200°C, 5 kg), for example, in the range of 1 to 1000 g/10 minutes and preferably 5 to 30 g/10 minutes.

The block copolymer used in the present invention can be produced by a conventional method. As a method for producing such a block copolymer, for example, an aromatic vinyl monomer and a conjugated diene monomer are sequentially polymerized by an anionic living polymerization method to form a polymer block, and the necessary Depending on the method, a method of performing coupling by reacting a coupling agent may be mentioned.

Further, as the block copolymer used in the present invention, (a) the aromatic vinyl-conjugated diene block copolymer represented by Ar-D, and (b) Ar-D-Ar and/or (Ar-D ) When using at least an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer represented by nX, the following method can be employed.

That is, first, an aromatic vinyl monomer is polymerized by an anionic living polymerization method, and then a conjugated diene monomer is added and polymerized to obtain a diblock copolymer having an active terminal. Then, by adding less than 1 molar equivalent of a coupling agent to the active terminal of the diblock copolymer having an active terminal, part of the diblock copolymer having an active terminal is subjected to a coupling reaction. , (Ar-D)nX After obtaining an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer represented by A method of deactivating the polymer to obtain a diblock copolymer represented as Ar-D is included. At this time, a bifunctional coupling agent such as dichlorosilane, monomethyldichlorosilane, dimethyldichlorosilane, diphenyldimethoxysilane, diphenyldiethoxysilane, dichloroethane, dibromoethane, methylene chloride, and dibromomethane is used as a coupling agent. By using it, an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer represented by Ar-D-Ar (D contains the residue of the coupling agent) can be obtained.

(a) an aromatic vinyl-conjugated diene block copolymer represented as Ar-D and (b) an aromatic vinyl-conjugate represented as Ar-D-Ar and/or (Ar-D)nX The content ratio of the diene-aromatic vinyl block copolymer is not particularly limited, but the content ratio of (a) the aromatic vinyl-conjugated diene block copolymer represented by Ar-D is preferably 10 to 90. % by mass, more preferably 20 to 80% by mass. In addition, the content of the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer represented by (b) Ar-D-Ar and/or (Ar-D)nX is preferably 10 to 90 mass. %, more preferably 20 to 80% by mass.

As the conjugated diene-aromatic vinyl thermoplastic elastomer, a random copolymer of an aromatic vinyl monomer and a conjugated diene monomer can be used instead of the block copolymer described above. A random copolymer of an aromatic vinyl monomer and a conjugated diene monomer can be produced, for example, by living anionic polymerization using an organic alkali metal compound as a polymerization initiator. Examples of organic alkali metal compounds include organic lithium compounds, organic sodium compounds, organic potassium compounds, etc. Specific examples include n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, and phenyllithium. , organic monolithium compounds such as stilbene lithium; organic polyvalent lithium compounds such as sodium naphthalene; organic sodium compounds such as sodium naphthalene; organic potassium compounds such as potassium naphthalene; Among these organometallic compounds, n-butyllithium is preferably used.

In the random copolymer of the aromatic vinyl monomer and the conjugated diene monomer, the content ratio of the aromatic vinyl monomer unit to the total monomer units is preferably 50% by mass or less, and 45% by mass. % or less, more preferably 40% by mass or less. By setting the content ratio of the aromatic vinyl monomer unit within the above range, it is possible to achieve a high balance between the affinity of the random copolymer for the crystalline material and the affinity of the block copolymer for the binder resin. It is possible to make the obtained toner more excellent in low-temperature fixability.

Furthermore, in the present invention, conjugated diene elastomers such as polybutadiene rubber and polyisoprene rubber can be suitably used as additives having a polydiene structure. Conjugated diene elastomers such as polybutadiene rubber and polyisoprene rubber can be produced, for example, by living anionic polymerization using an organic alkali metal compound as a polymerization initiator. As the organic alkali metal compound, for example, those mentioned above can be used.

The weight average molecular weight (Mw) of the additive having a polydiene structure is not particularly limited, but is a polystyrene conversion value measured by gel permeation chromatography (GPC) using tetrahydrofuran, preferably 60,000 to 350,000. and more preferably 80,000 to 250,000. By setting the weight average molecular weight (Mw) within the above range, the low-temperature fixability of the resulting toner can be further enhanced.

The content of the additive having a polydiene structure is preferably 0.5 to 20 parts by mass, more preferably 1.0 to 15 parts by mass, still more preferably 3 to 20 parts by mass, with respect to 100 parts by mass of the binder resin. 7 parts by mass. By setting the content of the additive having a polydiene structure within the above range, the low-temperature fixability of the resulting toner can be further enhanced.

Further, the content of the additive having a polydiene structure with respect to the content of the crystalline material is the weight ratio of "content of the additive having a polydiene structure/content of the crystalline material", and is preferably from 0.02 to 0.75, more preferably 0.10 to 0.55, still more preferably 0.20 to 0.50. By setting the content of the additive having a polydiene structure within the above range, the low-temperature fixability of the resulting toner can be further enhanced.

In addition, the colored resin particles may further contain a polar resin. The polar resin is not particularly limited, but an acrylic resin can be preferably used. The acrylic resin is a copolymer (acrylate-based copolymer) whose main component is at least one of acrylic acid ester and methacrylic acid ester and at least one of acrylic acid and methacrylic acid. Acrylic acid is preferred as the acid monomer.

Acrylic resins include, for example, copolymers of acrylic acid ester and acrylic acid, copolymers of acrylic acid ester and methacrylic acid, copolymers of methacrylic acid ester and acrylic acid, and copolymers of methacrylic acid ester and methacrylic acid. Copolymers, copolymers of acrylic acid esters, methacrylic acid esters and acrylic acid, copolymers of acrylic acid esters, methacrylic acid esters and methacrylic acid, and acrylic acid esters, methacrylic acid esters, acrylic acid and methacrylic acid A copolymer of Among these, it is preferable to use a copolymer of acrylic acid ester, methacrylic acid ester and acrylic acid.

The weight average molecular weight (Mw) of the acrylic resin is usually 6,000 to 50,000, preferably 8,000 to 25,000, more preferably 10,000 to 20,000.
When the weight average molecular weight (Mw) of the acrylic resin is within the above range, the low-temperature fixability can be further improved.

The ratio of acrylic acid ester monomer units, methacrylic acid ester monomer units, acrylic acid monomer units, and methacrylic acid monomer units in the acrylic resin varies depending on the acrylic acid ester and methacrylic acid monomer units during copolymer synthesis. It can be adjusted by the mass ratio of the amounts of acid ester, acrylic acid, and methacrylic acid added. The mass ratio of the amount added is, for example, (acrylic acid ester and/or methacrylic acid ester): (acrylic acid and/or methacrylic acid) = (99 to 99.95): (0.05 to 1). (Acrylic acid ester and / or methacrylic acid ester): (acrylic acid and / or methacrylic acid) = (99.4 to 99.9): (0.1 to 0.6) is preferable , (acrylic acid ester and/or methacrylic acid ester):(acrylic acid and/or methacrylic acid)=(99.5 to 99.7):(0.3 to 0.5).

Acrylic esters used to form acrylic resins include, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec- Butyl, tert-butyl acrylate, n-pentyl acrylate, sec-pentyl acrylate, isopentyl acrylate, neopentyl acrylate, n-hexyl acrylate, isohexyl acrylate, neohexyl acrylate, sec-hexyl acrylate, and acrylic acid tert-hexyl and the like, among which ethyl acrylate, n-propyl acrylate, isopropyl acrylate and n-butyl acrylate are preferred, and n-butyl acrylate is more preferred.

Methacrylate esters used to form acrylic resins include, for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec- Butyl, tert-butyl methacrylate, n-pentyl methacrylate, sec-pentyl methacrylate, isopentyl methacrylate, neopentyl methacrylate, n-hexyl methacrylate, isohexyl methacrylate, neohexyl methacrylate, sec-hexyl methacrylate, and methacryl acid tert-hexyl and the like, among which methyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, and n-butyl methacrylate are preferred, and methyl methacrylate is more preferred.

Although commercially available acrylic resins can be used, they can be produced by known methods such as solution polymerization, aqueous solution polymerization, ion polymerization, high-temperature and high-pressure polymerization, and suspension polymerization.

The amount of the polar resin added is preferably 0.3 to 4 parts by mass, more preferably 0.5 to 3 parts by mass, more preferably 0.6 to 2.5 parts by mass, based on 100 parts by mass of the binder resin. It is more preferably 0.7 to 2 parts by mass, and particularly preferably 0.7 to 2 parts by mass. By setting the amount of the polar resin to be added within the above range, the effect of the addition can be made sufficient while improving the environmental stability.

<Heating and kneading process, pulverizing process>
In the pulverization method, the binder resin, colorant, charge control agent, and crystalline material described above, as well as other additives such as additives having a polydiene structure and polar resins, which are added as necessary, are used. Mixing is performed using a mixer such as a ball mill, a V-type mixer, a Henschel mixer (trade name), a high-speed dissolver, an internal mixer, or a Fallberg. Next, the mixture obtained above is melt-kneaded while being heated using a pressure kneader, a twin-screw extruder kneader, rollers, or the like, and then the resulting kneaded product is subjected to a hammer mill, a cutter mill, a roller mill, or the like. Coarsely pulverize using a pulverizer. Furthermore, after fine pulverization using a pulverizer such as a jet mill or a high-speed rotary pulverizer, the colored resin particles are classified into desired particle sizes by a classifier such as an air classifier or an air classifier. Get a grind. The heating temperature at the time of melt-kneading may be a temperature at which melt-kneading is possible. is 110-160°C. The time for melt-kneading is preferably 1 to 60 minutes, more preferably 5 to 20 minutes.

<Dispersion process>
Next, the pulverized product of the colored resin particles obtained above is dispersed in an aqueous dispersion medium to obtain a dispersion liquid of the colored resin particles.

The aqueous dispersion medium used in the dispersion step is obtained by dissolving or dispersing the dispersion stabilizer in the aqueous medium. As the aqueous medium, water may be used alone, but a water-soluble solvent may also be used in combination. Examples of water-soluble solvents include lower ketones such as dimethylformamide, tetrahydrofuran, acetone, and methyl ethyl ketone.

The dispersion stabilizer is not particularly limited as long as it is a compound capable of imparting dispersibility for dispersing the pulverized colored resin particles in an aqueous medium. Examples of the organic dispersion stabilizer include polyvinyl water-soluble polymers such as alcohol, methylcellulose, gelatin; surfactants such as anionic surfactants, nonionic surfactants and amphoteric surfactants; Inorganic dispersion stabilizers include metal oxides such as aluminum oxide and titanium oxide; sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate and magnesium carbonate; calcium phosphate; phosphates such as aluminum phosphate; metal hydroxides such as aluminum hydroxide, magnesium hydroxide and ferric hydroxide; inorganic particles such as silica, titanium dioxide and aluminum oxide; Among these, inorganic dispersion stabilizers are preferred, phosphates or metal hydroxides are more preferred, and metal hydroxides are even more preferred.

Among the inorganic dispersion stabilizers, a poorly water-soluble inorganic dispersion stabilizer is preferable. In particular, the poorly water-soluble inorganic dispersion stabilizer is dispersed in an aqueous medium in the form of colloid particles That is, it is preferably used in the form of a colloidal dispersion containing colloidal particles of a water-insoluble inorganic dispersion stabilizer. By using the poorly water-soluble inorganic dispersion stabilizer in the form of a colloidal dispersion containing colloidal particles of the poorly water-soluble inorganic dispersion stabilizer, the particle size distribution of the colored resin particles can be narrowed. By washing, the residual amount in the obtained toner can be easily suppressed to a low level, so that fine line reproducibility can be further improved, and furthermore, environmental stability is also contributed.

Colloidal dispersions containing sparingly water-soluble inorganic dispersion stabilizer colloidal particles include, for example, alkali metal hydroxides and/or alkaline earth metal hydroxides and water-soluble polyvalent metal salts (alkaline earth hydroxides). Metal salts are excluded.) can be prepared by reacting them in an aqueous medium.

Examples of alkali metal hydroxide salts include lithium hydroxide, sodium hydroxide, and potassium hydroxide. Alkaline earth metal hydroxides include barium hydroxide and calcium hydroxide.

The water-soluble polyvalent metal salt may be any water-soluble polyvalent metal salt other than the compounds corresponding to the alkaline earth metal hydroxides. Examples include magnesium chloride, magnesium phosphate, magnesium sulfate, and the like. magnesium metal salts; calcium metal salts such as calcium chloride, calcium nitrate, calcium acetate and calcium sulfate; aluminum metal salts such as aluminum chloride and aluminum sulfate; barium salts such as barium chloride, barium nitrate and barium acetate; zinc chloride and zinc nitrate , zinc salts such as zinc acetate; Among these, magnesium metal salt, calcium metal salt, and aluminum metal salt are preferred, magnesium metal salt is more preferred, and magnesium chloride is particularly preferred. The water-soluble polyvalent metal salts can be used either singly or in combination of two or more.

The method for reacting the above alkali metal hydroxide salt and/or alkaline earth metal hydroxide salt with the above water-soluble polyvalent metal salt in an aqueous medium is not particularly limited, but the alkali metal hydroxide salt and / Or a method of mixing an aqueous solution of an alkaline earth metal hydroxide and an aqueous solution of a water-soluble polyvalent metal salt. In this case, from the viewpoint that the particle size of the sparingly water-soluble metal hydroxide colloidal particles can be suitably controlled, while stirring the aqueous solution of the water-soluble polyvalent metal salt, hydroxide is added to the aqueous solution. A method of mixing by gradually adding an aqueous solution of an alkali metal salt and/or an alkaline earth metal hydroxide salt is preferred.

Although the ratio of the alkali metal hydroxide salt and/or alkaline earth metal hydroxide to the water-soluble polyvalent metal salt is not particularly limited, the amount of alkali metal hydroxide and/or alkaline earth metal hydroxide used is The chemical equivalent ratio b/a of the chemical equivalent b of the alkali metal hydroxide salt and/or the alkaline earth metal hydroxide salt to the chemical equivalent a of the water-soluble polyvalent metal salt is 0.3 ≤ b/ The amount preferably satisfies the relationship a≦1.0, and more preferably the amount satisfies the relationship 0.4≦b/a≦1.0.

The amount of the dispersion stabilizer used is preferably 1 part by mass or more, more preferably 10 to 500 parts by mass with respect to 100 parts by mass of the ground material of the colored resin particles, from the viewpoint of good dispersion of the ground material of the colored resin particles. parts, more preferably 20 to 300 parts by mass.

In the dispersion step, the method of dispersing the colored resin particles in the aqueous dispersion medium is not particularly limited, but a method of adding the colored resin particles to the aqueous dispersion medium and stirring with a stirring device is suitable. At this time, the stirring temperature is not particularly limited, but is preferably 10 to 40° C., more preferably 20 to 30° C., and the stirring time is not particularly limited, but is preferably 1 minute to 2 hours. It is preferably 3 minutes to 1 hour.

Alternatively, in the dispersing step, after adding the colored resin particles to the aqueous dispersion medium, the colored resin particles are dispersed in the aqueous dispersion medium by performing a dispersion treatment to obtain a cavitation effect. A mode in which a liquid is obtained may be employed.

Dispersion treatment that produces a cavitation effect is a dispersion method that uses shock waves that are generated when high energy is applied to a liquid and the vacuum bubbles in the liquid burst.

Specific examples of dispersion processing that can obtain a cavitation effect include dispersion processing using ultrasonic waves, dispersion processing using a high-shear stirring device using an in-line emulsifying disperser, and dispersion processing using a jet mill. Only one of these distributed processes may be performed, or a plurality of distributed processes may be combined. More specifically, dispersion treatment using an ultrasonic homogenizer, dispersion treatment using a high-shear stirring device, and dispersion treatment using a jet mill are preferably used as the dispersion treatment for obtaining the cavitation effect. Note that conventionally known devices may be used as these devices.

The treatment time of the dispersion treatment for obtaining the cavitation effect is preferably 1 to 300 minutes, more preferably 5 to 100 minutes. The treatment temperature at this time is preferably 10 to 50°C, more preferably 20 to 40°C.

<Heating process>
Next, the dispersion liquid of the colored resin particles prepared in the dispersion step is heated at a temperature between the glass transition temperature Tg of the colored resin particles and 95° C. or less for a heating time of 5 minutes or more and 10 hours or less.

In the present invention, in the dispersing step, a dispersion liquid of colored resin particles is prepared, and the prepared dispersion liquid of colored resin particles is heated under the above conditions, so that the sphericity of the colored resin particles is adjusted to a suitable level. This can further increase the average circularity of the obtained colored resin particles, and furthermore, the domain structure of the crystalline material described later can be more preferably formed in the colored resin particles. becomes possible.

The heating temperature in the heating step is preferably at least the glass transition temperature Tg of the colored resin particles and at most 95° C., more preferably at least 10° C. higher than the glass transition temperature Tg of the colored resin particles (i.e., Tg+10° C. or higher). ), 94° C. or lower, more preferably a temperature higher than the glass transition temperature of the colored resin particles by 15° C. (that is, Tg+20° C. or higher), and 93° C. or lower. Although the specific heating temperature in the heating step is not particularly limited, it is preferably 40 to 90°C, more preferably 45 to 85°C, even more preferably 50 to 80°C, and particularly preferably 55 to 75°C. The heating time in the heating step is preferably 5 minutes or longer and 10 hours or shorter, more preferably 10 minutes or longer and 10 hours or shorter, and still more preferably 30 minutes or longer and 8 hours or shorter.

Then, the dispersion liquid of the colored resin particles that has been heat-treated under the above conditions in the heating step can be subjected to a series of operations of washing, filtration, dehydration, and drying according to a conventional method, and repeated several times as necessary. preferable.

First, in order to remove the dispersion stabilizer remaining in the dispersion of the colored resin particles after the heat treatment, it is preferable to wash the dispersion of the colored resin particles after the heat treatment by adding an acid or an alkali. . When the dispersion stabilizer used is an acid-soluble compound, it is preferable to add an acid to the dispersion of the colored resin particles for washing. In the case of a soluble compound, it is preferable to wash by adding an alkali to the dispersion liquid of the colored resin particles after the heat treatment.

When an acid-soluble compound is used as the dispersion stabilizer, an acid is added to the aqueous dispersion of the colored resin particles after the heat treatment, and the pH is adjusted to preferably 6.5 or less, more preferably 6.0. It is preferable to adjust as follows. As the acid to be added, inorganic acids such as sulfuric acid, hydrochloric acid and nitric acid, and organic acids such as formic acid and acetic acid can be used. sulfuric acid is particularly preferred.

Various known methods can be used for dehydration and filtration, and are not particularly limited. Examples thereof include centrifugal filtration, vacuum filtration, and pressure filtration. Also, the drying method is not particularly limited, and various methods can be used.

In addition, in the present invention, it is preferable to include a preheating step of preheating the dispersion liquid of the colored resin particles obtained in the dispersing step before the heating step. In this case, it is preferable that the dispersion liquid of the colored resin particles that has undergone the preheating step is subjected to heat treatment in the above heating step.

The preheating temperature in the preheating step is preferably 10 to 1°C lower than the glass transition temperature Tg of the colored resin particles (Tg-10 to Tg-1°C) and higher than the melting point mp of the crystalline material. is also 10° C. or more lower temperature (mp-10° C. or less), more preferably 8 to 2° C. lower than the glass transition temperature Tg of the colored resin particles (Tg-8 to Tg-2° C.), and , mp-8 to mp-5° C., which is 8 to 5° C. lower than the melting point mp of the crystalline material. The preheating time is preferably 30 minutes or more and 10 hours or less, more preferably 60 minutes or more and 5 hours or less. By setting the preheating temperature and the preheating time within the above ranges, it is possible to more preferably form the domain structure of the crystalline material, which will be described later, in the colored resin particles.

As described above, the colored resin particles constituting the toner of the present invention can be produced.

In the above description, the method for producing the colored resin particles constituting the toner of the present invention is exemplified using the pulverization method, which is an example of a dry method. For example, it may be produced by a suspension polymerization method, which is an example of a wet method.

In the suspension polymerization method, colored resin particles constituting the toner of the present invention are produced as follows. First, a polymerizable monomer composition is prepared by mixing and dissolving a polymerizable monomer, a colorant, a charge control agent, a crystalline material, and other additives added as necessary. Then, the polymerizable monomer composition is dispersed in an aqueous dispersion medium, a polymerization initiator is added, and droplets of the polymerizable monomer composition are formed to form a polymerizable monomer. A suspension of the composition is obtained. Subsequently, the obtained suspension of the polymerizable monomer composition is heated to initiate polymerization, whereby the water of the colored resin particles containing the binder resin, the colorant, the charge control agent, and the crystalline material is dissolved. A series of operations of washing, filtering, dehydrating, and drying after obtaining a dispersion are repeated several times as necessary to produce the colored resin particles constituting the toner of the present invention.

The colored resin particles constituting the toner of the present invention are crystals in the cross section of the colored resin particles observed in the backscattered electron image of the scanning electron microscope when the cross section is observed in the backscattered electron image of the scanning electron microscope. The total area ratio of the domains of the crystalline material is 10 to 30%, and the number of domains of the crystalline material in the cross section of the colored resin particle observed by a backscattered electron image of a scanning electron microscope is one particle. The average number of particles present per unit is in the range of 10 to 40. According to the present invention, the toner obtained by setting the total area ratio of the domains of the crystalline material and the number of domains of the crystalline material contained in the colored resin particles constituting the toner as described above, It has excellent low-temperature fixability, excellent hot-offset resistance, fine-line reproducibility and blade cleanability in a well-balanced manner, and can appropriately suppress toner ejection after being left at a high temperature. .

FIG. 1 shows a cross-sectional photograph of a backscattered electron image of a scanning electron microscope (FE-SEM) of the colored resin particles obtained in Example 6, which will be described later. As shown in FIG. 1, the colored resin particles of the present invention have a structure in which domains of a crystalline material (dark colored portions in FIG. 1) are dispersed in the colored resin particles. In the present invention, the total area ratio of the domains of the crystalline material in the cross section of the colored resin particles observed by a backscattered electron image of a scanning electron microscope (i.e., the ratio of the crystalline material to the area of the cross section of the colored resin particles The ratio of the area indicated by the domain) is set in the range of 10 to 30%. The total area fraction of the domains of crystalline material is preferably 15-28%, more preferably 18-26%.

In addition, in the present invention, the number of domains of the crystalline material present in the cross section of the colored resin particles observed by a backscattered electron image of a scanning electron microscope is 5 to 40 on average per particle. range. The number of domains of crystalline material present is preferably 10-35, more preferably 15-30.

The total area ratio of domains of the crystalline material and the number of domains of the crystalline material in the cross section of the colored resin particles observed by a backscattered electron image of a scanning electron microscope can be measured, for example, by the following method. . That is, first, the colored resin particles are mixed with, for example, a curable material such as a two-liquid condensation type epoxy adhesive and cured to prepare a cured product, and the prepared cured product is cut using a microtome or the like. and prepare a sample for cross-sectional observation. Next, the cross section of the colored resin particles is observed by measuring the backscattered electron image of the prepared sample for cross section observation using a scanning electron microscope. In this case, it is desirable to adjust the measurement conditions so that the domain of the crystalline material can be easily observed.

Then, a cross-sectional photograph of the colored resin particles obtained by measurement using a backscattered electron image of a scanning electron microscope is analyzed using image analysis software (for example, "DNP particle image analysis software" (manufactured by Dai Nippon Printing Co., Ltd.)). , the image analysis can determine the total area ratio of the domains of the crystalline material and the number of existing domains of the crystalline material. Specifically, the total area ratio of the domains of the crystalline material is obtained by measuring 100 or more colored resin particles, and by image analysis, the total area of the colored resin particles and the total area of the domain portion of the crystalline material. can be calculated using these. In addition, the number of existing domains of the crystalline material is obtained by measuring 100 or more colored resin particles, obtaining the number of the colored resin particles to be measured and the total number of domain portions of the crystalline material, and using them. can be calculated. In the measurement, the colored resin particles having a particle diameter within ±3 μm of the volume average particle diameter (Dv) of the colored resin particles measured by a particle size analyzer using a Coulter counter were measured. (That is, colored resin particles whose particle diameter deviates from the volume average particle diameter (Dv) by more than ±3 μm are excluded from measurement.).

The method for adjusting the total area ratio of the domains of the crystalline material and the number of domains of the crystalline material in the cross section of the colored resin particles observed by the backscattered electron image of the scanning electron microscope to the above range is particularly limited. However, for example, a method of adjusting the type and amount of the crystalline material used, a method of adding an additive having a polydiene structure to the colored resin particles, a method of producing the colored resin particles, the above dispersion step and A method including a heating step, a method including a preheating step, and the like are appropriately combined.

In addition, in the colored resin particles of the present invention, the total area ratio of the domains of the crystalline material and the number of domains of the crystalline material are within the above ranges, and the shape of the domains of the crystalline material is as follows. is preferred. That is, in the colored resin particles of the present invention, the average circularity of the domains of the crystalline material in the cross section of the colored resin particles observed by a backscattered electron image of a scanning electron microscope is preferably 0.50 or less, and more It is preferably 0.10 to 0.47, more preferably 0.20 to 0.45. In the colored resin particles of the present invention, the average value of the ratio of the minor axis to the major axis of the domain of the crystalline material in the cross section of the colored resin particle observed by a backscattered electron image of a scanning electron microscope is 0.60 or less. is preferably 0.15 to 0.50, more preferably 0.25 to 0.40. When one or both of the average circularity of the domains of the crystalline material and the average value of the ratio of the short diameter to the long diameter are within the above ranges, the effects of the present invention can be further enhanced.

The average circularity of the domains of the crystalline material and the average ratio of the short diameter to the long diameter of the domains of the crystalline material in the cross section of the colored resin particles observed by the backscattered electron image of the scanning electron microscope are, for example, In the same manner as in the case of the total area ratio of the domains of the crystalline material and the number of existing domains of the crystalline material, a sample for cross-sectional observation is prepared, and the prepared sample for cross-sectional observation is subjected to a scanning electron microscope. It can be measured by observing the cross section of the colored resin particles by performing measurement using a backscattered electron image.

Then, the cross-sectional photograph of the colored resin particles obtained by the measurement of the backscattered electron image of the scanning electron microscope can be obtained by image analysis using image analysis software in the same manner as described above. Specifically, the average circularity of the domains of the crystalline material is obtained by measuring 100 or more colored resin particles, specifying the shape of the domain portion of the crystalline material for each domain portion, and determining the shape of the domain portion of the specified domain portion. It can be obtained by calculating the degree of circularity from the shape and averaging the obtained results. In addition, the average value of the ratio of the short diameter to the long diameter of the domain of the crystalline material is obtained by measuring the long diameter and the short diameter for each domain part with 100 or more colored resin particles as the measurement object, and based on this, the short diameter to the long diameter It can be obtained by calculating the diameter ratio (=minor diameter/major diameter) and averaging the obtained results. In the measurement, as described above, colored resin particles having a particle diameter within ±3 μm of the volume average particle diameter (Dv) of the colored resin particles measured with a Coulter counter are measured. conduct.

The average circularity of the domains of the crystalline material and the average ratio of the short diameter to the long diameter of the domains of the crystalline material in the cross section of the colored resin particles observed by the backscattered electron image of the scanning electron microscope are within the above ranges. Although the method is not particularly limited, for example, a method of adjusting the type and amount of the crystalline material used, a method of adding an additive having a polydiene structure to the colored resin particles, and a method of manufacturing the colored resin particles In this case, a method in which the above-described dispersing step and heating step, a preheating step, and the like are appropriately combined may be used.

The average circularity of the colored resin particles constituting the toner of the present invention is not particularly limited, but is preferably 0.950 to 1.000, more preferably 0.955 to 0.995, and still more preferably 0. 0.960 to 0.995.

The volume average particle diameter (Dv) of the colored resin particles is preferably 5.0 to 12 μm, more preferably 5.5 to 10 μm, still more preferably 6.0 to 9.0 μm, from the viewpoint of image reproducibility. 0 μm. By setting the volume average particle diameter (Dv) of the colored resin particles within the above range, it is possible to appropriately suppress the deterioration of the image quality and the reduction of the resolution of the image due to fogging and the like while improving the fluidity of the toner. .

In addition, the particle size distribution (Dv/Dp), which is the ratio of the volume average particle size (Dv) to the number average particle size (Dp) of the spherical colored resin particles, is preferably 1.00 to 1.40. It is more preferably 1.10 to 1.30, still more preferably 1.11 to 1.25, and particularly preferably 1.13 to 1.20. The volume-average particle diameter (Dv) and number-average particle diameter (Dp) of the spherical colored resin particles can be determined by, for example, a particle size analyzer using a Coulter counter (manufactured by Beckman Coulter, trade name: Multisizer). can be measured using

The colored resin particles may be used as a toner as they are or by mixing carrier particles (ferrite, iron powder, etc.) with the colored resin particles. For adjustment, a one-component toner may be obtained by adding and mixing an external additive to the colored resin particles using a high-speed stirrer (for example, FM mixer (trade name, manufactured by Nippon Coke Kogyo Co., Ltd.)). Further, a two-component toner may be prepared by mixing colored resin particles, an external additive, and carrier particles.

The stirrer for performing the external addition treatment is not particularly limited as long as it is a stirrer capable of adhering the external additive to the surface of the colored resin particles. , Super Mixer (trade name, manufactured by Kawada Seisakusho Co., Ltd.), Q Mixer (trade name, manufactured by Nippon Coke Industry Co., Ltd.), Mechano Fusion System (trade name, manufactured by Hosokawa Micron Corporation), Mechanomill (trade name, manufactured by Okada Seiko Co., Ltd.), etc. The external addition treatment can be performed using a stirrer capable of mixing and stirring.

External additives include inorganic fine particles made of silica, titanium oxide, aluminum oxide, zinc oxide, tin oxide, calcium carbonate, calcium phosphate, barium titanate, strontium titanate, zinc stearate, magnesium stearate and cerium oxide; (Meth)acrylic acid ester resins such as polystyrene resins and polymethyl methacrylate resins, styrene-(meth)acrylate copolymers, silicone resins, melamine resins, zinc stearate, and organic fine particles made of calcium stearate. be done. The organic fine particles may be, for example, core-shell type particles in which the core contains a (meth)acrylic acid ester resin and the shell contains a polystyrene resin. Among these, inorganic fine particles are preferred, silica and titanium oxide are more preferred, and silica is particularly preferred. Moreover, it is preferable to use two or more kinds of fine particles in combination as an external additive. Although each of these external additives can be used alone, it is preferable to use two or more of them in combination. The external additive preferably contains hydrophobic fine particles, and more preferably contains hydrophobic inorganic fine particles.

The external additive is preferably used in a proportion of 0.3 to 6 parts by mass, more preferably in a proportion of 1.2 to 3 parts by mass, relative to 100 parts by mass of the colored resin particles.

In the toner of the present invention, as colored resin particles, the total area ratio of the domains of the crystalline material and the number of existing domains of the crystalline material in the cross section of the colored resin particles observed with a backscattered electron image of a scanning electron microscope are as described above. Since it is within the range, it is excellent in offset resistance, fine line reproducibility and blade cleanability in a well-balanced manner, and the occurrence of toner ejection after being left at a high temperature is suppressed.

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

(1) Glass transition temperature The glass transition temperature was measured according to ASTM D3418-82.

(2) Volume average particle diameter Dv of colored resin particles
The volume-average particle diameter Dv of the colored resin particles was measured by a particle size analyzer (manufactured by Beckman Coulter, trade name: Multisizer) using a Coulter counter. The measurement with this Multisizer was carried out under the conditions of aperture diameter: 100 μm, dispersion medium: Isoton II (trade name), concentration: 10%, and number of measured particles: 100,000.
Specifically, 0.2 g of the colored resin particles was placed in a beaker, and an aqueous surfactant solution (manufactured by Fuji Film Co., Ltd., trade name: Drywell) was added therein as a dispersant. 2 ml of a dispersing medium was further added thereto to wet the colored resin particles, and then 10 ml of a dispersing medium was added, dispersed for 1 minute with an ultrasonic disperser, and then measured with the above particle size measuring instrument.

(3) Average Circularity of Colored Resin Particles 10 ml of ion-exchanged water was placed in advance in a container, and 0.2 g of a surfactant aqueous solution (manufactured by Fuji Film Co., Ltd., trade name: Drywell) was added thereto as a dispersant. Further, 0.2 g of colored resin particles were added, and dispersion treatment was performed with an ultrasonic disperser at 60 W for 3 minutes. The concentration of colored resin particles at the time of measurement was adjusted to 3,000 to 10,000 particles/μL, and the flow type particle image was obtained for 1,000 to 10,000 colored resin particles having an equivalent circle diameter of 0.4 μm or more. Measurement was performed using an analyzer (trade name: FPIA-2100, manufactured by Sysmex Corporation). The average circularity was obtained from the measured values.
The circularity is shown in the following formula, and the average circularity is the average value.
(Circularity) = (perimeter of circle equal to projected area of particle)/(perimeter of projected image of particle)

(4) Fine structure of domain of crystalline material in cross section of colored resin particles by backscattered electron image of scanning electron microscope Colored resin particles are mixed with a two-liquid condensation type epoxy adhesive and cured to obtain a cured product. was prepared, and the prepared cured product was cut using a microtome or the like to prepare a sample for cross-sectional observation. Next, the cross section of the colored resin particles was observed by measuring the backscattered electron image of the prepared sample for cross section observation using a scanning electron microscope (manufactured by JEOL Ltd., product name: JSM-7610F). At this time, the measurement conditions were adjusted so that the domains of the crystalline material could be easily observed.
Then, using image analysis software (DNP particle image analysis software, manufactured by Dai Nippon Printing Co., Ltd.), image analysis is performed on a cross-sectional photograph of the colored resin particles obtained by measurement using a backscattered electron image of a scanning electron microscope. , the total area ratio of the domains of the crystalline material, the number of existing domains of the crystalline material (average number of existing domains per particle), the average circularity of the domains of the crystalline material, and the minor axis to the major axis of the domains of the crystalline material were measured respectively. In this case, 100 or more colored resin particles having a particle diameter within ±3 μm with respect to the volume average particle diameter (Dv) of the colored resin particles were measured.
The total area ratio of the domains of the crystalline material is obtained by obtaining the total area of the colored resin particles and the total area of the domain portion of the crystalline material, and from these results, the number of domains of the crystalline material in the cross section of the colored resin particles. It was obtained by calculating the area ratio.
The number of existing domains of the crystalline material (average number of existing domains per particle) is obtained by obtaining the number of colored resin particles to be measured and the total number of domain parts of the crystalline material. was obtained by dividing by the number of colored resin particles.
The average circularity of the domains of the crystalline material is obtained by specifying the shape of the domain portion of the crystalline material for each domain portion, calculating the circularity from the shape of the specified domain portion, and averaging the obtained results. asked.
The average value of the ratio of the minor axis to the major axis of the domain of the crystalline material is obtained by measuring the major axis and the minor axis for each domain part, and calculating the ratio of the minor axis to the major axis (=minor axis/major axis) based on this, It was determined by averaging the obtained results.

(5) Minimum Fixing Temperature of Toner A fixing test was performed using a commercially available non-magnetic one-component developing printer (printing speed: 20 ppm) modified so that the temperature of the fixing roll section can be changed. In the fixing test, a solid black print (100% print density) is printed, the temperature of the fixing roll of the modified printer is changed by 5°C, and the fixing rate of the toner at each temperature is measured. I went looking for a relationship. The fixing rate was calculated from the ratio of the image densities before and after the tape was peeled off after the tape was peeled off in the solid black print area (print density 100%). That is, if the image density before tape peeling is ID (before) and the image density after tape peeling is ID (after), the fixing rate can be calculated by the following formula.
Fixing rate (%)=(ID (after)/ID (before))×100
Here, the tape peeling operation means that an adhesive tape (manufactured by Sumitomo 3M, trade name: Scotch Mending Tape 810-3-18) is attached to the measurement part of the test paper, pressed with a constant pressure to adhere, and then It is a series of operations to peel off the adhesive tape in the direction along the paper at a constant speed. The image density was measured using a reflective image densitometer (manufactured by Macbeth, trade name: RD914).
In this fixing test, the lowest fixing roll temperature at which the fixing rate exceeded 80% was defined as the lowest fixing temperature of the toner.

(6) Hot offset resistance Using a commercially available non-magnetic one-component development printer (24-sheet printer; printing speed = 24 sheets/min) modified so that the temperature of the fixing roll section can be changed, hot offset resistance was measured. did the test. In the hot offset test, the temperature of the fixing roll was changed from 150°C to 100°C by 5°C, and a 5 cm square solid image was printed on paper (trade name: Vitality, manufactured by Xerox). The presence or absence of the hot offset phenomenon was visually observed to determine whether fusion had occurred.
In this hot offset test, it was confirmed whether or not toner fusion occurred on the fixing roll. , and the case where the toner was fused to the fixing roll was evaluated as "x".

(7) Blowout after Storage at High Temperature A commercial non-magnetic one-component developing toner cartridge was filled with toner and left in an environment at 50° C. for 120 hours (5 days). After standing, continuous printing was performed for 2 hours using a commercially available non-magnetic one-component developing printer, and the toner was visually checked for ejection, and evaluated according to the following criteria.
(double-circle): There was no blowout at all.
Good: There was a slight ejection from a part of the developing machine.
Δ: There was a slight ejection from the entire surface of the developing machine.
x: There were many blowouts from the entire surface of the developing machine.

(8) Reproducibility of Fine Lines Toner was placed in a commercially available non-magnetic one-component development printer, left for one day in an N/N environment, and then a continuous line image of 2×2 dot lines (approximately 85 μm in width) was obtained. was formed, and printing was performed up to 10,000 sheets. The moving speed of the photoreceptor surface at the position contacting the cleaning blade was set to 12 cm/sec.
Every 500 printed sheets, measurement was performed using a printing evaluation system (trade name: RT2000 manufactured by YA-MA), and density distribution data of the line image was collected. At this time, the line width is the full width at half the maximum value of the density, and the line width of the first line image is used as a reference. If the line width difference is 10 μm or less, the first line image is reproduced. Investigate the number of sheets that can maintain the line width difference of 10 μm or less. ``○'' for those that are still fine, ``△'' for those that maintain the thin line on 5,000 or more and less than 7,000 sheets, and ``X'' for those that maintain the thin line only on less than 5,000 sheets. divided into levels.

(9) Blade Cleaning Property A cleaning blade sample for testing was attached to the printer of (8) above, toner was put in the cartridge, and printing paper was set, and then left under N/N environment for a whole day and night. Thereafter, continuous printing was performed from the initial stage at a density of 5%, and the photoreceptor and charging roll were visually observed every 500 sheets printed to test whether streaks (filming) due to poor cleaning occurred. The presence or absence of the ink was tested until 10,000 sheets were printed. The test results indicated the number of printed sheets at which cleaning failure occurred. "A" indicates that no cleaning failure occurred even after printing 10,000 sheets or more continuously; "O" indicates that 5,000 or more sheets could be printed continuously, but "△" indicates that cleaning failure occurred up to 7,000 sheets, and "X" indicates that cleaning failure occurred up to 5,000 sheets. Divided into 4 levels.

[Production Example 1, production of styrene-butyl acrylate copolymer (α-1) (binder resin)]
After adding 0.2 parts of a nonionic dispersant (manufactured by Kuraray Co., Ltd., "PVA235") to 200 parts of ion-exchanged water, a monomer mixture consisting of 86 parts of styrene and 14 parts of butyl acrylate, and a polymerization initiator (permeable Benzoyl oxide) was added thereto, and the mixture was maintained at 130° C. for 2 hours with stirring to carry out suspension polymerization to obtain a suspension of a copolymer.
The resulting suspension was cooled to 30° C., dehydrated with a centrifugal dehydrator, and dried at 50° C. for 24 hours to obtain a styrene-butyl acrylate copolymer (α-1). The obtained styrene-butyl acrylate copolymer (α-1) contained 86% styrene units and 14% butyl acrylate units, and had a glass transition temperature Tg of 54°C.

[Production Example 2, production of block copolymer composition (β-1) (additive having polydiene structure)]
23.2 kg of cyclohexane, 1.5 mmol of N,N,N',N'-tetramethylethylenediamine (hereinafter referred to as TMEDA) and 1.70 kg of styrene were added to a pressure-resistant reactor and stirred at 40°C. 99.1 millimoles of n-butyllithium was added thereto and polymerized for 1 hour while the temperature was raised to 50°C. The polymerization conversion rate of styrene was 100% by mass. Subsequently, 6.03 kg of isoprene was continuously added to the reactor over 1 hour while controlling the temperature to maintain 50-60°C. After the addition of isoprene was completed, polymerization was continued for an additional hour to form styrene-isoprene diblock copolymer B (Copolymer B represented by Ar-D). The polymerization conversion rate of isoprene was 100%. Then, 15.0 millimoles of dimethyldichlorosilane was added as a coupling agent, and the coupling reaction was carried out for 2 hours to obtain a styrene-isoprene-styrene triblock copolymer (copolymer A represented by Ar-D-Ar). was formed. Thereafter, 198 millimoles of methanol as a polymerization terminator was added and mixed well to terminate the reaction, thereby obtaining a reaction solution containing block copolymer composition (β-1). A portion of the obtained reaction solution was taken out, and the weight average molecular weight, content ratio, and vinyl bond content of each block copolymer and the entire block copolymer composition were determined. Table 1 shows the results obtained. Then, 0.3 parts of 2,6-di-tert-butyl-p-cresol was added as an antioxidant to 100 parts of the reaction solution thus obtained (containing 30 parts of the polymer component) and mixed. Then, the mixed solution was dropped little by little into hot water heated to 85 to 95°C to volatilize the solvent to obtain a precipitate, which was pulverized and dried with hot air at 85°C to obtain a block together. A polymer composition (β-1) was recovered. The obtained block copolymer composition (β-1) was measured for melt index, and Table 1 shows the obtained results.

[Production Example 3, Production of Colloidal Dispersion Containing Colloidal Magnesium Hydroxide Particles]
An aqueous solution obtained by dissolving 7.3 parts of sodium hydroxide in 50 parts of ion-exchanged water was gradually added to an aqueous solution obtained by dissolving 10.4 parts of magnesium chloride in 280 parts of ion-exchanged water under stirring for 10 minutes. , a colloidal dispersion containing colloidal magnesium hydroxide particles was prepared.

[Example 1]
(Production of colored resin particles)
100 parts of the styrene-butyl acrylate copolymer (α-1) obtained in Production Example 1 as the binder resin, 5 parts of carbon black (manufactured by Mitsubishi Chemical Corporation, trade name: MA-100) as the colorant, crystal 20 parts of behenyl stearate (melting point: 69.2° C., number average molecular weight of 592) as an ester wax, and the block copolymer composition (β-1) obtained in Production Example 2 (having a polydiene structure Additive) 5 parts, and as a charge control agent, 5 parts of a charge control resin (Fujikura Kasei Co., Ltd., styrene acrylic resin containing quaternary ammonium base, functional group content 4%), Henschel mixer (manufactured by Nippon Coke Kogyo Co., Ltd., Trade name: FM20B). Then, the resulting mixture was melt-kneaded at 145° C. for 10 minutes using a twin-screw extruder, and the resulting kneaded product was cooled. Next, the cooled kneaded material is pulverized with a mechanical pulverizer (manufactured by Turbo Kogyo Co., Ltd., trade name: Turbo Mill), and classified with an elbow jet classifier (manufactured by Nittetsu Mining Co., Ltd., trade name: EJ-LABO). Thus, pulverized irregular colored resin particles having a number volume average particle diameter of 7.1 μm were obtained (heat kneading step, pulverizing step).

Next, 4.0 parts of the colloidal dispersion containing the magnesium hydroxide colloidal particles obtained in Production Example 3 and 400.0 parts of ion-exchanged water are added to 10 parts of the pulverized colored resin particles obtained above. Part of the mixed solution was added and stirred to obtain a dispersion of colored resin particles (dispersion step). Next, a sample tube containing a stirrer was placed in a constant temperature water bath set at a temperature of 50°C, and the dispersion liquid of the colored resin particles obtained above was placed in the sample tube and slowly stirred for 120 minutes. Preheating was performed by allowing the mixture to stand still for a minute to obtain a dispersion liquid of colored resin particles after preheating (preheating step). Next, a sample tube containing a stirrer is placed in a constant temperature water bath set at 70°C, and the preheated colored resin particle dispersion obtained above is added to the sample tube and slowly stirred. The dispersion of the colored resin particles after preheating was heat-treated by allowing the dispersion liquid of the colored resin particles to be spheroidized (heating step).

Next, while stirring the dispersion of the colored resin particles after the heat treatment, sulfuric acid is added until the pH reaches 4.5, and acid washing is performed at a temperature of 25° C. for 10 minutes. After the colored resin particles were separated by filtration and washed with water, the washing water was filtered. The electrical conductivity of the filtrate at this time was 11 μS/cm. Further, the colored resin particles after washing and filtering were dehydrated and dried to obtain dried colored resin particles. Then, using the obtained colored resin particles, the volume average particle diameter Dv, the average circularity, and the fine structure of the domain of the crystalline material in the cross section of the colored resin particles in the backscattered electron image of the scanning electron microscope. I made a measurement. Table 2 shows the results. The glass transition temperature of the colored resin particles was substantially the same as the glass transition temperature of the binder resin (the same applies to Examples 2 to 8 and Comparative Examples 1 to 3, which will be described later).

(Toner manufacturing)
To 100 parts of the colored resin particles obtained above, 0.5 parts of silica fine particles having a volume average particle diameter of 12 nm (manufactured by Nippon Aerosil Co., Ltd., trade name: RX-200) hydrophobized with hexamethyldisilazane. 2.0 parts of silica fine particles (manufactured by Nippon Aerosil Co., Ltd., trade name: RX-50) hydrophobized with hexamethyldisilazane and having a volume average particle diameter of 40 nm, and a specific resistance of 40 Ω cm. 0.5 parts of titanium oxide fine particles surface-treated with antimony-doped tin oxide (manufactured by Titan Kogyo Co., Ltd., trade name: EC-300, volume average particle diameter: 0.3 μm) was added, and a Henschel mixer was used. A toner was obtained by mixing for 10 minutes at a rotational speed of 3000 rpm. Then, using the obtained toner, the minimum fixing temperature, hot offset resistance, ejection after high temperature storage, fine line reproducibility, and blade cleaning performance were evaluated. Table 2 shows the results.

[Example 2]
Colored resin particles and toner were obtained and evaluated in the same manner as in Example 1, except that the amount of behenyl stearate used as the ester wax was changed to 30 parts. Table 2 shows the results.

[Example 3]
Colored resin particles and toner were obtained and evaluated in the same manner as in Example 1, except that the amount of behenyl stearate used as the ester wax was changed to 40 parts. Table 2 shows the results.

[Example 4]
Colored resin particles and toner were obtained and evaluated in the same manner as in Example 1, except that the amount of behenyl stearate used as the ester wax was changed to 10 parts. Table 2 shows the results.

[Example 5]
Coloring was carried out in the same manner as in Example 1, except that 30 parts of pentaerythritol tetrapalmitate (melting point: 71.0°C, number average molecular weight: 1088) was used as the ester wax instead of behenyl stearate as the ester wax. Resin particles and toner were obtained and evaluated in the same manner. Table 2 shows the results.

[Example 6]
Coloring was carried out in the same manner as in Example 1, except that 30 parts of pentaerythritol tetrastearate (melting point: 76.0°C, number average molecular weight: 1200) was used as the ester wax instead of behenyl stearate as the ester wax. Resin particles and toner were obtained and evaluated in the same manner. Table 2 shows the results.

[Example 7]
Colored resin particles and toner were obtained in the same manner as in Example 2, except that the amount of the block copolymer composition (β-1) obtained in Production Example 2 was changed to 15 parts, and evaluated in the same manner. did Table 2 shows the results.

[Example 8]
Colored resin particles and toner were obtained in the same manner as in Example 2, except that the amount of the block copolymer composition (β-1) obtained in Production Example 2 was changed to 1 part, and evaluated in the same manner. did Table 2 shows the results.

[Comparative Example 1]
Colored resin particles and toner were obtained in the same manner as in Example 2, except that the block copolymer composition (β-1) obtained in Production Example 2 was not used, and evaluated in the same manner. Table 2 shows the results.

[Comparative Example 2]
Colored resin particles and toner were obtained in the same manner as in Example 1, except that the amount of behenyl stearate used as the ester wax was changed to 5 parts, and evaluated in the same manner. Table 2 shows the results.

[Comparative Example 3]
78 parts of styrene and 22 parts of n-butyl acrylate as polymerizable monomers, 5 parts of carbon black (manufactured by Mitsubishi Chemical Corporation, trade name: #25B) as a black colorant, and an in-line emulsifying disperser (manufactured by Pacific Machinery Co., Ltd.) , trade name: Milder) to obtain a polymerizable monomer mixture.

To the polymerizable monomer mixture obtained above, 1.0 parts of a charge control resin (quaternary ammonium group-containing styrene acrylic resin) as a charge control agent, 30 parts of behenyl stearate as an ester wax, and 1 part of the resulting block copolymer composition (β-1) (additive having a polydiene structure), 0.6 parts of divinylbenzene as a crosslinkable polymerizable monomer, and t-dodecylmercaptan as a molecular weight modifier 1.6 parts were added, mixed and dissolved to prepare a suspension in which the polymerizable monomer composition was dispersed (polymerizable monomer composition dispersion).

The polymerizable monomer composition dispersion liquid prepared above was put into a reactor equipped with a stirring blade, and the temperature was raised to 90°C to initiate the polymerization reaction. When the polymerization conversion reached almost 100%, 1 part of methyl methacrylate as a polymerizable monomer for the shell and 2,2'-azobis (2,2'-azobis ( 2-Methyl-N-(2-hydroxyethyl)-propionamide) (trade name: VA-086, manufactured by Wako Pure Chemical Industries, Ltd., water-soluble) was added (0.3 parts), and the reaction was continued at 90° C. for 4 hours. Thereafter, the reaction was terminated by water cooling to obtain an aqueous medium dispersion containing colored resin particles having a core-shell structure.

Sulfuric acid was added dropwise to the aqueous dispersion of the colored resin particles obtained above while stirring at room temperature, and acid washing was performed until the pH reached 6.5 or less. Subsequently, filtration separation was performed, 500 parts of ion-exchanged water was added to the obtained solid content to reslurry, and water washing treatment (washing, filtration, and dehydration) was repeated several times. Next, filtration separation was performed, and the obtained solid content was placed in a container of a dryer and dried at 45° C. for 48 hours to obtain dried colored resin particles. Then, evaluation was performed in the same manner as in Example 1 using the obtained colored resin particles. Table 2 shows the results.

Also, using the colored resin particles obtained above, a toner was obtained in the same manner as in Example 1 and evaluated in the same manner as in Example 1. Table 2 shows the results.

As shown in Table 2, the total area ratio of the domains of the crystalline material in the cross section of the colored resin particles observed by the backscattered electron image of the scanning electron microscope is 10 to 30%, and the domains of the crystalline material are In Examples 1 to 8, in which the average number of particles present per particle is in the range of 10 to 40, the obtained toner has excellent low-temperature fixability, hot offset resistance, and fine line reproduction. It was excellent in well-balanced properties and blade cleanability, and the occurrence of toner ejection after being left at a high temperature was suppressed. FIG. 1 shows a cross-sectional photograph of the colored resin particles obtained by a backscattered electron image of a scanning electron microscope in Example 6. As shown in FIG.

On the other hand, the total area ratio of the domains of the crystalline material or the number of domains of the crystalline material in the cross section of the colored resin particles observed by the backscattered electron image of the scanning electron microscope is outside the scope of the present invention. In certain Comparative Examples 1 to 3, results were inferior in hot offset resistance, fine line reproducibility, or blade cleaning performance, and toner ejection occurred after being left at high temperatures.

Claims

A toner for electrostatic charge image development containing colored resin particles containing a binder resin, a colorant, a charge control agent, and a crystalline material,
When the cross section of the colored resin particles is observed with a backscattered electron image of a scanning electron microscope, the total area ratio of the domains of the crystalline material in the cross section of the colored resin particles is 10 to 30%, and the colored resin A toner for electrostatic charge image development, wherein the average number of domains of the crystalline material present in the cross section of the particle is in the range of 5 to 40 per particle.
2. The method according to claim 1, wherein an average circularity of domains of the crystalline material in the cross section of the colored resin particles is 0.50 or less when the cross section of the colored resin particles is observed with a backscattered electron image of a scanning electron microscope. A toner for developing an electrostatic charge image as described above.
When the cross section of the colored resin particles is observed with a backscattered electron image of a scanning electron microscope, the average value of the ratio of the short diameter to the long diameter of the domains of the crystalline material in the cross section of the colored resin particles is 0.60 or less. 3. The toner for electrostatic charge image development according to claim 1 or 2, wherein:
The toner for electrostatic charge image development according to any one of claims 1 to 3, wherein the content of the crystalline material is 5.0 to 40.0 parts by mass with respect to 100 parts by mass of the binder resin.
The toner for electrostatic charge image development according to any one of claims 1 to 4, wherein the crystalline material is an ester wax having a number average molecular weight (Mn) of 500 to 1,550.
The toner for electrostatic charge image development according to any one of claims 1 to 5, wherein the colored resin particles further contain an additive having a polydiene structure.
The toner for electrostatic charge image development according to claim 6, wherein the content of the additive having a polydiene structure is 0.5 to 20 parts by mass with respect to 100 parts by mass of the binder resin.
The toner for electrostatic charge image development according to any one of claims 1 to 7, wherein the binder resin is a styrene-(meth)acrylic acid ester copolymer.
The toner for electrostatic charge image development according to any one of claims 1 to 8, which is a positively charged toner.
The toner for electrostatic charge image development according to any one of claims 1 to 9, which is produced by a pulverization method or a suspension polymerization method.