JP2007334005A - Electrostatic charge image developing toner and method for manufacturing resin grain - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic charge image developing toner capable of obtaining a high definition image free from character crushing, fogging and photoreceptor filming, and to provide a method for manufacturing resin grains used therefor. <P>SOLUTION: In the electrostatic charge image developing toner, resin grains are obtained by polymerizing a radical polymerizable surfactant and a radical polymerizable monomer, surfactant residues are chemically bonded to the surfaces of the resin grains, and also, the resin grains are flocculated with at least one kind selected from a coloring agent, wax and a charge controlling agent. The method for manufacturing the resin grains is also provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrostatic charge image developing toner and a method for producing resin particles used therefor.

  In the field of electrophotographic image forming technology such as copying machines and printers, with the advancement of digital technology, recently, fine dots of 1200 dpi (dpi represents the number of dots per inch, that is, 2.54 cm) level. An image forming technique that accurately reproduces an image has been demanded. In order to accurately reproduce such minute dot images, the electrostatic charge image developing toner (hereinafter, also simply referred to as toner) has been studied to reduce its diameter, and emulsification association that allows various control in the manufacturing process. As a result, attention has been paid to the type toner, and it is possible to produce a small-diameter toner capable of reproducing a minute dot image (see, for example, Patent Document 1). As a result, high-definition images such as photographs can be formed using toner.

  The emulsion-associative toner is produced by aggregating functional particles with a pigment, wax, charge control agent and the like. A surfactant is used for aggregation. As a result, the charge amount of the toner is reduced due to the surfactant remaining on the toner surface, and the resin particles are reoriented by the surfactant that is not adsorbed on the dispersion (free surfactant) and aggregated with the resin particles. There has been a problem of filming of the photosensitive member due to pigment particles (free pigment) or wax particles (free wax) that have been stabilized independently without being used.

  On the other hand, countermeasures due to free surfactants are disclosed (for example, see Patent Document 2), and countermeasures due to free pigments are also disclosed (for example, refer to Patent Document 3). Yes.

However, even in the toner, the influence of the free surfactant cannot be excluded, and it is not sufficient to solve the problems of charge reduction and photoconductor filming.
JP 2000-214629 A JP 2002-351142 A JP 2005-17829 A

  An object of the present invention is to provide a toner for developing an electrostatic image capable of obtaining a high-quality image free from character crushing, fogging and photoconductor filming, and a method for producing resin particles used therefor.

  The above object of the present invention can be achieved by the following configuration.

  1. A resin particle obtained by polymerizing a radical polymerizable surfactant represented by the following general formula (1) or (2) and a radical polymerizable monomer, wherein the surface of the resin particle has a chemical residue. A toner for developing an electrostatic charge image, wherein the toner particles are bonded together and the resin particles are aggregated with at least one selected from a colorant, a wax, and a charge control agent.

(Wherein R ₁ represents hydrogen or a methyl group, R ₂ and R ₃ each independently represents an alkyl group having 1 to 20 carbon atoms, A represents an alkylene group having 2 to 4 carbon atoms, and n represents represents an integer of 1 to 20, M represents an alkali metal or NH _4.)
2. 2. A method for producing resin particles, wherein the resin particles according to 1 are produced by a miniemulsion polymerization method in which oil particles containing a radical polymerizable monomer and a wax are synthesized.

  3. 2. A method for producing resin particles, wherein the resin particles according to 1 are produced by a wax seed polymerization method in which a radical polymerizable monomer is dropped in advance in the presence of wax particles.

  According to the present invention, it is possible to provide a toner for developing an electrostatic charge image capable of obtaining a high-quality image free from character crushing, fogging and photoconductor filming, and a method for producing resin particles used therefor.

  The present invention will be described in more detail. In the surfactant used for emulsion polymerization, the resin particles are bonded and fused together at the time of association, so that the surface area of the associated particles is reduced. As a result, the surfactant cannot be adsorbed to the resin, and becomes free in the liquid. Organic pigments, waxes, charge control agents, etc. with low stability and high hydrophobicity adsorb surfactants and are stabilized. As a result, it is not taken into the associated particles and tends to exist on the toner surface. Further, the active agent that cannot be adsorbed remains locally on the toner surface.

  On the other hand, when resin particles obtained by polymerizing a radical polymerizable surfactant represented by the general formula (1) or (2) of the present invention and a radical polymerizable monomer are used, a surface active residue is chemically formed on the resin particles. The surfactant present on the toner surface is reduced. In addition, free surfactants generated during association are reduced, and free substances such as pigments, waxes and charge control agents are not present.

  Here, the surface active residue means the following group in the general formula (1) or (2).

-O- (AO) _n SO ₃ -M
In the general formula (1) or (2), R ₁ is hydrogen or a methyl group.

R ₂ and R ₃ each independently represents an alkyl group having 1 to 20 carbon atoms, and specific examples include octyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl and the like. . A mixture of these alkyl groups and the like may be used.

  A is an alkylene group having 2 to 4 carbon atoms, such as ethylene, propylene, butylene, and isobutylene.

  n is an integer of 1 to 20, more preferably in the range of 2 to 10.

M is an alkali metal atom such as sodium or potassium, or NH ₄ , and may be a mixture thereof.

  Specific examples of the radically polymerizable surfactants represented by the general formulas (1) and (2) of the present invention which are representative of the present invention are shown below, but the present invention is not limited thereto.

  As a production method, an α-olefin oxide having 12 or 14 carbon atoms and allyl alcohol were heated and reacted in the presence of a catalyst, and the obtained reaction composition or further alkylene oxide was added by a conventional method. The alkylene oxide adduct is sulfated with a sulfating agent such as sulfuric acid or sulfamic acid, neutralized with a basic substance as necessary, and represented by the general formula (1) or (2) of the present invention. Can be obtained.

  The addition amount is preferably 0.20 to 1.0% by mass ratio with respect to the radical polymerizable monomer. If it is 0.20% or less, the reaction is difficult to proceed in the micelle, and if it is 1.0% or more, the radical polymerizable surfactant represented by the general formula (1) or (2) that cannot contribute to the reaction. Will remain, resulting in the same result as a normal surfactant.

  Among the many radical polymerizable surfactants, the radical polymerizable surfactant represented by the general formula (1) or (2) of the present invention is excellent in the copolymerization of the radical polymerizable monomer. . When the polymerizable group of the radical polymerizable surfactant is a vinyl group, the copolymerizability with the radical polymerizable monomer is low, and an unreacted surfactant remains. In that case, it remains locally on the toner surface in the same manner as a normal surfactant.

  As a method for producing the toner for developing an electrostatic charge image of the present invention, a toner production method by an emulsion association method is preferably used. There are no particular restrictions on the method for producing the resin particles, but the resin particles in which multi-emulsion polymerization particles are synthesized by dispersing and synthesizing monomers and waxes in the presence of an emulsifier are formed by emulsion polymerization, and the presence of an emulsifier in wax. A toner production method is preferred in which wax seed polymerized particles, in which a monomer is polymerized on the surface of the particles by dispersing in (1), are combined (aggregated / fused) with resin particles having a multi-stage polymerization structure by emulsion polymerization.

  Specifically, the wax seed polymerized particles are obtained by sequentially adding a monomer having an acidic or basic polar group and another monomer to the wax emulsion, and polymerizing these monomers based on the wax fine particles, and the reaction proceeds. To do. As a result, polymer particles having a structure including a wax are obtained. The formed resin fine particles take, for example, a core / shell type, a phase separation type, an occlusion type, or a mixed form thereof.

  The wax contained in the resin fine particles is not particularly limited, and specifically, low molecular weight polyethylene or polypropylene, olefin wax such as a copolymer of polyethylene and other olefin polymer, paraffin wax, behen. Ester waxes with long chain aliphatic groups such as behenyl acid, montanic acid ester, glycerin ester, stearyl stearate, vegetable waxes such as hydrogenated castor oil and carbauba wax, and long chain alkyl groups such as distearyl ketone Ketone wax, silicone wax having alkyl group, higher fatty acid wax such as stearic acid, long chain fatty acid alcohol wax, long chain fatty acid polyhydric alcohol wax such as pentaerythritol and its partial ester wax, oleic amide And Higher fatty acid amide waxes such as stearic acid amide, and the like. Among these, by using a wax having a melting point of 100 ° C. or less, good fixability can be obtained, preferably 40 ° C. to 90 ° C., more preferably 50 ° C. to 80 ° C.

  Next, a method for producing miniemulsion polymerized particles will be described. The wax is dispersed in the presence of an emulsifier to form a wax emulsion. The average particle size of the dispersed wax particles is preferably 10 nm to 1.0 μm, particularly preferably 100 nm to 500 nm. When the size of the wax particles is within the above range, the formed resin fine particles are likely to aggregate on the particle surface described later, which is preferable for making the toner surface uniform. In addition, it is presumed that the monomer polymerization on the surface of the wax particles is also positively affected, and the polymerization proceeds with certainty, so that the resin fine particles including the wax are efficiently produced. The size of the wax particles can be measured using a particle size distribution measuring device. For example, a commercially available particle size such as Microtrac particle size distribution measuring device UPA (manufactured by Nikkiso Co., Ltd.) using a laser diffraction scattering method can be used. There is a distribution measuring device.

  As the emulsifier for dispersing the wax, a radical polymerizable surfactant represented by the general formula (1) or (2) of the present invention can be used. Two or more known cationic surfactants, anionic surfactants, nonionic surfactants and the like may be used in combination.

  The radical polymerizable surfactant represented by the general formula (1) or (2) of the present invention is copolymerizable with the radical polymerizable monomer as the main component in the polymerization.

  In the case of emulsion polymerization, the resulting latex particles are radically polymerized by copolymerization of the main component radically polymerizable monomer and the radically polymerizable surfactant represented by the general formula (1) or (2) of the present invention. The surfactant is chemically bonded and immobilized.

  When wax particles are used as seeds, the radically polymerizable surfactant is obtained by copolymerizing the wax particles with the monomer that has absorbed the vinyl monomer and absorbed the radically polymerizable surfactant adsorbed on the surface of the particles. Immobilization by chemical bonding of is possible.

  The surfactant that can be used in combination with the radically polymerizable surfactant represented by the general formula (1) or (2) of the present invention will be described. Examples of the cationic surfactant include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide and the like.

  Examples of the anionic surfactant include aliphatic soaps such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium laurate.

  Further, examples of the nonionic surfactant include dodecyl polyoxyethylene ether, hexadecyl polyoxyethylene ether, nonylphenyl polyoxyethylene ether, lauryl polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, monodecanoyl Sucrose etc. are mentioned.

  The size of the resin fine particles is in the range of 50 nm to 3.0 μm as an average particle diameter, preferably 100 nm to 1.0 μm, and particularly preferably 100 nm to 500 nm. By setting the size of the resin fine particles within the above range, the resin fine particles can be aggregated on the particle surface at an appropriate rate. As a result, it becomes easy to control the agglomeration rate at the time of toner production, and it becomes easy to produce a toner having a uniform surface. Further, when the size of the resin fine particles is within the above range, a small-diameter toner is easily obtained, and high-resolution image formation is promoted. The size of the resin fine particles can be measured using a particle size distribution measuring device as in the case of the wax particle measurement described above. For example, a microtrack particle size distribution measuring device UPA (Nikkiso Co., Ltd.) using a laser diffraction scattering method can be used. Commercially available particle size distribution measuring devices such as those manufactured by K.K.

Aggregation Step The aggregation step is a step of forming colored particles using resin particles (colored or non-colored resin particles) obtained by the polymerization step and colorant particles. In the aggregation step, resin particles and colorant particles can be aggregated together with release agent particles, internal additive particles such as charge control agents, and the like.

  The colorant particles can be prepared by dispersing the colorant in an aqueous medium. The dispersion treatment of the colorant is performed in a state where the surfactant concentration is set to a critical micelle concentration (CMC) or more in water. The disperser used for the dispersion treatment of the colorant is not particularly limited, but preferably an ultrasonic disperser, a mechanical homogenizer, a pressure disperser such as a manton gorin or a pressure homogenizer, a sand grinder, a Getzmann mill, a diamond fine mill, or the like. Examples thereof include a medium type disperser.

  The colorant particles may be surface modified. In the surface modification method of the colorant, the colorant is dispersed in a solvent, the surface modifier is added to the molecular weight solution, and the system is reacted by raising the temperature. After completion of the reaction, the colorant is separated by filtration, washed and filtered with the same solvent, and dried to obtain a colorant (pigment) treated with the surface modifier.

  A preferred aggregating method is to add a salting-out agent composed of an alkali metal salt, an alkaline earth metal salt, or the like as an aggregating agent having a critical aggregation concentration or more in water in which resin particles and colorant particles are present, This is a method of agglomerating at or above the glass transition point of the resin particles.

  Aging is preferably performed by thermal energy (heating).

  Specifically, the liquid containing the associated particles is heated and stirred to adjust the shape of the associated particles to the desired circularity by the heating temperature, the stirring speed, and the heating time to obtain toner base particles. is there.

  In the next step, the toner base dispersion liquid is cooled (rapidly cooled). As a cooling treatment condition, cooling is performed at a cooling rate of 1 to 20 ° C./min. The cooling treatment method is not particularly limited, and examples thereof include a method of cooling by introducing a refrigerant from the outside of the reaction vessel, and a method of cooling by directly introducing cold water into the reaction system.

Washing / Drying Step In this solid-liquid separation / washing step, the solid-liquid separation process for solid-liquid separation of the toner base from the dispersion of the toner base cooled to a predetermined temperature in the above-described step, and the toner cake separated into solid and liquid A cleaning process is performed to remove deposits such as a surfactant and a salting-out agent from (an aggregate obtained by agglomerating a toner base in a wet state in a cake shape).

  In the washing treatment, the filtrate is washed with water until the electric conductivity of the filtrate reaches 10 μS / cm. Examples of the filtration method include a centrifugal separation method, a vacuum filtration method using Nutsche and the like, and a filtration method using a filter press and the like, and are not particularly limited.

  The drying step is a step of drying the washed toner cake to obtain a dried toner base. Examples of dryers used in this process include spray dryers, vacuum freeze dryers, vacuum dryers, etc., stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers It is preferable to use a stirring dryer or the like. The water content of the dried colored particles is preferably 5% by mass or less, more preferably 2% by mass or less. In addition, when the dried colored particles are aggregated by weak interparticle attractive force, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.

External Addition Processing Step This step is a step of preparing a toner by mixing an external additive as necessary with the dried toner base.

  As an external additive mixing device, a mechanical mixing device such as a Henschel mixer or a coffee mill can be used.

  Next, the compounds (binder resin, colorant, charge control agent) constituting the toner used in the present invention will be described.

(Binder resin)
As the polymerizable monomer constituting the binder resin, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4-dichloro are used. Styrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn -Styrene or styrene derivatives such as decylstyrene, pn-dodecylstyrene, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-methacrylate Octyl, 2-ethylhexyl methacrylate, stearyl methacrylate Methacrylic acid ester derivatives such as lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, acrylic Acrylates such as isobutyl acid, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, olefins such as ethylene, propylene, isobutylene, vinyl chloride, vinylidene chloride, Halogenated vinyls such as vinyl bromide, vinyl fluoride and vinylidene fluoride, vinyl esters such as vinyl propionate, vinyl acetate and vinyl benzoate, vinyl methyl ether, vinyl ethyl ether Vinyl ethers such as ether, vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone, N-vinyl compounds such as N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, vinyl naphthalene, vinyl pyridine, etc. Examples include vinyl compounds, acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide. These vinyl monomers can be used alone or in combination.

  Further, it is more preferable to use a combination of monomers having an ionic dissociation group as the polymerizable monomer constituting the binder resin. For example, it has a substituent such as a carboxyl group, a sulfonic acid group, a phosphoric acid group as a constituent group of the monomer, specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumar Acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, acid phosphooxyethyl methacrylate, 3-chloro-2-acid phosphooxy And propyl methacrylate.

  Furthermore, multifunctional such as divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, etc. It is also possible to use a crosslinkable resin by using a functional vinyl.

  These polymerizable monomers can be polymerized using a radical polymerization initiator. In this case, an oil-soluble polymerization initiator can be used in the suspension polymerization method. Examples of the oil-soluble polymerization initiator include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carboxyl). Nitriles), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo- or diazo-based polymerization initiators such as azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate , Cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4,4- t-butylperoxycyclohexyl) propane, tris- Peroxide polymerization initiator or a peroxide such as t- butylperoxy) triazine and the like polymeric initiator having a side chain.

  Moreover, when using an emulsion polymerization method, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, hydrogen peroxide and the like.

(Coloring agent)
As the colorant used in the present invention, a known inorganic or organic colorant can be used. Specific colorants are shown below.

  Examples of the black colorant include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite.

  Examples of the colorant for magenta or red include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48; 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of the colorant for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. And CI Pigment Yellow 138.

  Examples of the colorant for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15; 2, C.I. I. Pigment blue 15; 3, C.I. I. Pigment blue 15; 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. Pigment blue 66, C.I. I. And CI Pigment Green 7.

  These colorants may be used alone or in combination of two or more as required. The addition amount of the colorant is set in the range of 1 to 30% by mass, preferably 2 to 20% by mass with respect to the whole toner.

(Charge control agent)
A charge control agent can be added to the toner of the present invention as necessary. As the charge control agent, known compounds can be used. Specifically, nigrosine dyes, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes, salicylic acid Examples thereof include a metal salt or a metal complex thereof. Examples of the metal contained include Al, B, Ti, Fe, Co, and Ni. Particularly preferred as the charge control agent is a metal complex compound of a benzylic acid derivative. In addition, when the content of the charge control agent is preferably 0.1 to 20.0% by mass with respect to the whole toner, good results can be obtained.

(External additive)
The toner of the present invention is preferably prepared by adding an external additive. The addition amount of the external additive is preferably 0.1 to 10.0% by mass with respect to the whole toner.

  The external additive is not particularly limited, and known inorganic fine particles, organic fine particles, lubricants and the like can be used.

  Examples of the inorganic fine particles include general particles such as silica, titania, alumina, and strontium titanate particles. The particle size of the external additive is preferably 10 nm to 1.0 μm.

  Examples of the organic fine particles include particles such as polystyrene, polymethyl methacrylate, styrene-methyl methacrylate copolymer, benzoguanamine, and melamine.

  Examples of the lubricant include metal salts of higher fatty acids. Specific examples of such higher fatty acid metal salts include: stearic acid metal salts such as zinc stearate, aluminum stearate, copper stearate, magnesium stearate, calcium stearate; zinc oleate, manganese oleate, iron oleate, olein Oleic acid metal salts such as acid copper and magnesium oleate; palmitate metal salts such as zinc palmitate, copper palmitate, magnesium palmitate and calcium palmitate; linoleic acid metal salts such as zinc linoleate and calcium linoleate; ricinol Examples include ricinoleic acid metal salts such as zinc acid and calcium ricinoleate.

<Developer>
The image forming method according to the present invention includes a method of developing an electrostatic latent image on a photosensitive member using a developer prepared by mixing toner and resin particles, or development with different mixing ratios of toner and resin particles. A method of developing a plurality of developing devices loaded with an agent, selecting a developing device in accordance with a document to be printed, and developing an electrostatic latent image on the photosensitive member, and the like can be given.

  Hereinafter, a developer prepared by mixing toner and resin particles will be described.

  The developer of the present invention can be used as a one-component developer or a two-component developer. When used as a one-component developer, a developer obtained by mixing a non-magnetic one-component toner and resin particles, or a magnetic one-component toner containing about 0.1 to 0.5 μm of magnetic particles in the toner particles A developer in which resin particles are mixed can be used, and any developer can be used. Further, it can be used as a two-component developer in which a carrier, toner and resin particles are mixed. In this case, conventionally known materials typified by iron-containing magnetic particles such as iron, ferrite, and magnetite can be used as the magnetic particles of the carrier, but ferrite particles or magnetite particles are particularly preferable. The magnetic particles preferably have a volume average particle diameter of 15 to 100 μm, more preferably 20 to 80 μm.

  The volume average particle diameter of the carrier can be measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by Sympathetic).

  The carrier is preferably a coating carrier in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, and for example, olefin resin, styrene resin, styrene-acrylic resin, silicon resin, ester resin, or fluorine-containing polymer resin is used. The resin for constituting the resin-dispersed carrier is not particularly limited, and known resins can be used. For example, styrene-acrylic resin, polyester resin, fluorine resin, phenol resin, etc. are used. be able to.

  Further, the mixing ratio of the toner / resin particle mixture and the carrier is preferably in the range of (resin particle + toner) / carrier = 1/10 to 1/50 (mass%) in mass ratio.

  The mixing method of the toner, the resin particles, and the carrier is not particularly limited, and can be mixed by a known method. Specifically, the resin particles, the toner, and the carrier are charged into a mixer such as “Henschel mixer” (manufactured by Mitsui Miike Chemical Co., Ltd.) and stirred. The mixing temperature is preferably 20 to 35 ° C., the mixing time is 5 to 30 minutes, and the rotational peripheral speed of the stirring blade is preferably 20 to 45 m / s.

<Image forming method>
The developer of the present invention develops an electrostatic latent image formed on a photoreceptor with a developer to form a toner image, transfers the formed toner image to an image support, and fixes the image support to a fixing device. It is preferably used in an image forming method of a contact-type fixing method in which fixing is performed by passing between heating members (heating nips) constituting the.

<< Preparation of Resin Particle Dispersion 1 >>
A monomer mixed solution composed of 175 g of styrene, 60 g of n-butyl acrylate, 15 g of methacrylic acid, and 7 g of n-octyl mercaptan was placed in a stainless steel kettle equipped with a stirrer, and 100 g of pentaerythritol tetrabehenate was added thereto. A monomer mixture was prepared by heating to 70 ° C. and dissolving.

  On the other hand, after the surfactant solution in which 2.50 g of the radical polymerizable surfactant 1-1 of the present invention was dissolved in 1350 g of ion-exchanged water was heated to 70 ° C., the monomer mixture was added and mixed. An emulsified dispersion was prepared by dispersing for 30 minutes with a mechanical disperser CLEARMIX (manufactured by M Technique Co., Ltd.) having a circulation path.

  On the other hand, 1500 g of ion-exchanged water is put in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction device separately, and the emulsified dispersion is added to a place where the temperature is previously set to 78 ° C. Then, potassium persulfate 7 Polymerization initiator solution in which 0.5 g was dissolved in 150 g of ion-exchanged water was added, and this system was polymerized by heating and stirring at 78 ° C. for 1.5 hours. Further, 12 g of potassium persulfate was dissolved in 220 g of ion-exchanged water. The polymerization initiator solution thus added was added, and a monomer mixed solution consisting of 320 g of styrene, 100 g of n-butyl acrylate, 35 g of methacrylic acid, and 7.5 g of n-octyl mercaptan was added over 1 hour under the temperature condition of 80 ° C. It was dripped. After completion of the dropping, the mixture was heated and stirred for 2 hours to proceed the polymerization, and then cooled to 28 ° C. to obtain a resin particle dispersion 1.

<< Preparation of resin particle dispersion 2 >>
In the production of the resin particle dispersion 1, the same procedure as in the production of the resin particle dispersion 1 was conducted, except that 2.50 g of the radical polymerizable surfactant 1-2 was used instead of the radical polymerizable surfactant 1-1. The resin particle dispersion 2 was obtained.

<< Preparation of Resin Particle Dispersion 3 >>
In the production of the resin particle dispersion 1, the same procedure as in the production of the resin particle dispersion 1 was performed, except that 1.55 g of the radical polymerizable surfactant 1-3 was used instead of the radical polymerizable surfactant 1-1. The resin particle dispersion 3 was obtained.

<< Preparation of Resin Particle Dispersion 4 >>
In the production of the resin particle dispersion 1, the same procedure as in the production of the resin particle dispersion 1 was performed except that 2.50 g of the radical polymerizable surfactant 2-1 was used instead of the radical polymerizable surfactant 1-1. The resin particle dispersion 4 was obtained.

<< Preparation of resin particle dispersion 5 >>
In the production of the resin particle dispersion 1, the same procedure as in the production of the resin particle dispersion 1 was performed except that 3.25 g of the radical polymerizable surfactant 2-2 was used instead of the radical polymerizable surfactant 1-1. The resin particle dispersion 5 was obtained.

<< Preparation of Resin Particle Dispersion 6 >>
A surfactant solution, pentaerythritol tetrabehen, in which 5.50 g of the radical polymerizable surfactant 1-1 of the present invention is dissolved in 1350 g of ion-exchanged water in a four-headed Kolben equipped with a stirrer, a cooling pipe and a temperature sensor. After adding and mixing 100 g of the acid ester, an emulsified dispersion was prepared by dispersing at 80 ° C. for 30 minutes with a mechanical disperser CLEARMIX (manufactured by M Technique Co., Ltd.).

  On the other hand, 1500 g of ion-exchanged water is put in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introducing device separately, and the emulsified dispersion is added to a place where the temperature is previously 78 ° C. Then, potassium persulfate 19 A polymerization initiator aqueous solution in which 0.5 g is dissolved in 370 g of ion-exchanged water is added, and a mixture of 495 g of styrene, 160 g of n-butyl acrylate, 50 g of methacrylic acid, and 8.5 g of n-octyl mercaptan is dropped over 90 minutes, A polymerization reaction was performed. After dropping the mixture, the mixture was heated and stirred for 2 hours to proceed the polymerization, and then cooled to 28 ° C. to obtain a resin fine particle dispersion 6.

<< Preparation of Resin Particle Dispersion 7 >>
2.50 g of radical polymerizable surfactant 1-1 and 3000 g of ion-exchanged water were charged into a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device, and the internal temperature was raised to 80 ° C. . After heating, 10 g of potassium persulfate dissolved in 200 g of ion-exchanged water is added to obtain a liquid temperature of 80 ° C., and 552 g of styrene, 192 g of n-butyl acrylate, 70 g of methacrylic acid, and 5.5 g of n-octyl mercaptan are mixed. After dropping the solution over 2 hours, polymerization was performed by heating and stirring at 80 ° C. for 2 hours to prepare a resin particle dispersion 7.

<< Preparation of Resin Particle Dispersion 8 >>
Resin particle dispersion liquid except that 2.50 g of anionic surfactant A (C ₁₂ H ₂₅ OSO ₃ Na) was used instead of radical polymerizable surfactant 1-1 in the preparation of resin particle dispersion liquid 1. 1 was performed, and a resin particle dispersion 8 was obtained.

<< Preparation of Resin Particle Dispersion 9 >>
Preparation of the resin particle dispersion 1 was performed in the same manner as the preparation of the resin particle dispersion 1 except that 2.50 g of the following radical polymerizable surfactant B was used instead of the radical polymerizable surfactant 1-1. Resin particle dispersion 9 was obtained.

  The production methods of the obtained resin fine particle dispersions 1 to 9 are collectively shown in Table 1.

<< Preparation of Colorant Dispersion >>
90 g of sodium dodecyl sulfate was added to 1600 g of ion-exchanged water and dissolved by stirring. While stirring this liquid, 420 g of carbon black (Regal 330R (manufactured by Cabot Corporation)) is gradually added, and then dispersed by using a mechanical disperser CLEARMIX (manufactured by M Technique Co., Ltd.), thereby coloring. An agent particle dispersion was prepared. This is designated as “colorant particle dispersion 1”. The particle diameter of the colorant particles in “Colorant particle dispersion 1” was 110 nm as measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.).

<< Preparation of colored particles 1 >>
440 g of “resin particle dispersion 1”, 1100 g of ion-exchanged water, and 200 g of “colorant dispersion 1” are charged in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction device. After adjusting the liquid temperature to 30 ° C., 5 mol / L sodium hydroxide aqueous solution was added to adjust the pH to 10. Next, an aqueous solution in which 60 g of magnesium chloride was dissolved in 60 g of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After holding for 3 minutes, the temperature was raised and the system was heated to 90 ° C. over 60 minutes, and the particle growth reaction was continued while maintaining 90 ° C. In this state, the particle size of the associated particles was measured with “Coulter Multisizer III”, and when the median diameter on the volume basis reached 6.5 μm, an aqueous solution in which 190 g of sodium chloride was dissolved in 760 g of ion-exchanged water was added. Then, the particle growth is stopped, and further, as a ripening step, the mixture is heated and stirred at a liquid temperature of 90 ° C. to advance the fusion between the particles, to form a circular shape, and after 3 hours, is cooled to 30 ° C. Got.

<< Preparation of Colored Particles 2-6, 8, 9 >>
In the production of the colored particles 1, the resin particle dispersion 1 was changed to the resin particle dispersions 2 to 6, 8, and 9, respectively, and the colored particles 2 to 6, 8, and 9 were produced.

<< Preparation of colored particles 7 >>
Pentaerythritol tetrabehen, a surfactant solution in which 2.0 g of the radical polymerizable surfactant 1-1 of the present invention is dissolved in 1350 g of ion-exchanged water in a four-headed colben equipped with a stirrer, a cooling pipe and a temperature sensor. After adding and mixing 100 g of the acid ester, an emulsified dispersion was prepared by dispersing at 80 ° C. for 30 minutes with a mechanical disperser CLEARMIX (manufactured by M Technique Co., Ltd.).

  In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction device, 400 g of “resin particle dispersion 7”, 540 g of the above emulsified dispersion, 600 g of ion-exchanged water, “colorant dispersion” 1 ”200 g was charged, and the liquid temperature was adjusted to 30 ° C., and then the pH was adjusted to 10 by adding a 5 mol / L sodium hydroxide aqueous solution. Next, an aqueous solution in which 60 g of magnesium chloride was dissolved in 60 g of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After holding for 3 minutes, the temperature was raised and the system was heated to 90 ° C. over 60 minutes, and the particle growth reaction was continued while maintaining 90 ° C. In this state, the particle size of the associated particles was measured with “Coulter Multisizer III”, and when the median diameter on the volume basis reached 6.5 μm, an aqueous solution in which 190 g of sodium chloride was dissolved in 760 g of ion-exchanged water was added. Then, the particle growth is stopped, and further, as a ripening process, the mixture is heated and stirred at a liquid temperature of 90 ° C. to advance the fusion between the particles, to form a circular shape, and after 3 hours, is cooled to 30 ° C. Got.

<Production of developer>
The obtained “colored particles 1 to 9” were each 1% by mass of hydrophobic silica having a number average primary particle size of 12 nm and a hydrophobization degree of 68 nm, and a number average primary particle size of 20 nm. Hydrophobic titanium oxide having a degree of 63 was added so as to be 1% by mass, and mixed using a “Henschel Miki mixer (manufactured by Mitsui Miike Chemical Co., Ltd.)”. Thereafter, coarse particles were removed using a sieve having an opening of 45 μm to obtain the corresponding “toners 1 to 9”. Each of the produced toners 1 to 9 had a volume-based median diameter (D ₅₀ % diameter) of 6.5 μm.

  A developer having a toner concentration of 6% was prepared by mixing each toner with a ferrite carrier having a volume average particle diameter of 60 μm coated with a silicone resin.

"Evaluation methods"
As an evaluation apparatus, a commercially available monochrome image forming apparatus “bizhub PRO 1050 (manufactured by Konica Minolta Business Technology Co., Ltd.)” was used.

  In addition, the print is an image with a pixel rate of 10% (a character image with a pixel rate of 7% (characters with 4 points, 6 points, and 8 points), a human face photo, a solid white image, a solid black image, etc. each 1/4, The original images in FIG. 1) were used and 50,000 monochrome images were formed using the obtained developers 1 to 9, respectively, and the following evaluation was performed on the 50,000th sheet.

"Evaluation item"
<Visual evaluation of text crushing>
The above-described character image print was visually evaluated at an observation distance of 30 cm under an illumination environment of 2000 lux. The evaluation is as follows. If the character collapse evaluation is ◎, ○, △, it can be said that there is no practical problem.

◎: 4-point characters can be easily read without being affected by white background ○: 4-point characters are slightly difficult to read due to white background, but 6-point characters can be easily read △: Characters with 6 points or less Although it is difficult to interpret due to the influence of a white background, 8-point characters can be easily interpreted. ×: It is also difficult to interpret 8-point characters due to the influence of a white background.

<Occurrence of fogging>
The fog density is measured by first measuring and averaging the absolute image density at 20 locations using a Macbeth reflection densitometer “RD-918” for blank paper that has not been printed. Next, for the 50,000th white background portion of the evaluation formed image, the absolute image density at 20 locations was similarly measured and averaged, and the value obtained by subtracting the white paper density from this average density was evaluated as the fog density. If the fog concentration is 0.010 or less, it can be said that fog is practically no problem.

◎: Less than 0.003 ○: 0.003 to less than 0.006 Δ: 0.006 to 0.010 or less ×: Value greater than 0.010 <Photoconductor filming>
A large image such as a streak-like image defect (black streak, white streak) caused by photoconductor filming was visually determined for the 50,000th evaluation formed image. The criteria for determining black spots and streak-like image defects are as follows. Black spots and streak-like image defects (evaluated with halftone, solid white image, solid black image)
◎ (excellent): No occurrence even on a solid black image ○ (good): Some areas of the solid black image where the density is slightly thinner △ (possible): White streaks on the solid black image Although there are several, a level that is not conspicuous in a real image such as a printer image and has no problem in use. X (impossible): White streaks can be confirmed in the real image.

  From Table 2, it can be seen that the developer of the present invention gives a high-quality image free of character collapse, fogging and photoconductor filming.

Claims (3)

A resin particle obtained by polymerizing a radical polymerizable surfactant represented by the following general formula (1) or (2) and a radical polymerizable monomer, wherein the surface of the resin particle has a chemical residue. A toner for developing an electrostatic charge image, wherein the toner particles are bonded together and the resin particles are aggregated with at least one selected from a colorant, a wax, and a charge control agent.

(Wherein R ₁ represents hydrogen or a methyl group, R ₂ and R ₃ each independently represents an alkyl group having 1 to 20 carbon atoms, A represents an alkylene group having 2 to 4 carbon atoms, and n represents represents an integer of 1 to 20, M represents an alkali metal or NH _4.) A method for producing resin particles, wherein the resin particles according to claim 1 are produced by a miniemulsion polymerization method in which oil particles containing a radical polymerizable monomer and a wax are synthesized. A method for producing resin particles, characterized in that the resin particles according to claim 1 are produced by a wax seed polymerization method in which a radical polymerizable monomer is dropped in advance in the presence of wax particles.