JP2011128575A - Method for producing developing agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily produce a developing agent having a core-shell structure. <P>SOLUTION: As a dispersion liquid containing first fine particles and a dispersion liquid containing second fine particles, those satisfying the relationship represented by a formula (1) are used, and these two dispersion liquids are mixed with each other, and an aggregating agent and a pH adjusting agent are added thereto in sequence, whereby encapsulation is achieved by selective formation of core particles through aggregation of the first fine particles and shells through aggregation of the second fine particles. 15 mV≥¾Z2-Z1¾≥5 mV (1). In a formula (1), Z1 and Z2 represent zeta potentials of the first dispersion liquid and the second dispersion liquid, respectively, measured when aluminum sulfate is added to each dispersion liquid in an amount of 1% by weight based on the solid content in each dispersion liquid. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a developer for developing an electrostatic charge image and a magnetic latent image in electrophotography, electrostatic printing, and magnetic recording.

  Conventionally, as a toner manufacturing method in which the shape and surface composition of toner particles are intentionally controlled, a fine particle dispersion containing at least a resin and a colorant is used as an aggregating agent, and agglomeration and fusion are performed using a metal salt or a polymer aggregating agent. An agglomeration method is proposed. For example, an aggregation method using a metal salt is disclosed (see, for example, Patent Document 1 and Patent Document 2). Further, for example, an aggregation method using a polymer flocculant has been proposed (see, for example, Patent Document 3). In such an agglomeration method, the toner component is agglomerated uniformly inside and on the surface of the toner, so that a release agent is present on the surface of the toner after fusing, resulting in filming, deterioration of chargeability, etc. A stable image cannot be formed. In addition, a method for producing an electrophotographic toner having a core-shell structure has been proposed (for example, a shell particle dispersion separately prepared is added to and mixed with the core particles aggregated by the aggregation method described above and adhered to the surface of the aggregate particles. Patent Document 4 and Patent Document 5). Furthermore, a method for producing an electrophotographic toner having a three-layer core-shell structure with an intermediate layer having a wax between the core and shell has been proposed (see, for example, Patent Document 6).

  However, the conventional core-shell structure method has a problem that the process is complicated.

  An object of the present invention is to easily produce a developer having a core-shell structure.

The developer production method of the present invention includes a first dispersion containing first fine particles containing a first binder resin and a colorant, and at least the first binder resin and the first binder resin. Mixing a second dispersion containing second fine particles containing one of the different second binder resins to form a mixed dispersion;
After adding a flocculant to the mixed dispersion to selectively agglomerate the first microparticles to form core particles;
A method for producing a developer, comprising adding a pH adjuster to the mixed dispersion containing the core particles, aggregating the second fine particles on the core particle surfaces, and forming a shell.
Each of the first dispersion and the second dispersion has a solid content concentration of 5% by weight, and the zeta potential when aluminum sulfate is added to the solid content by 1% by weight is Z1, When Z2 is satisfied, the absolute value of the difference in zeta potential satisfies the relationship represented by the following formula (1).

15 mV ≧ | Z2-Z1 | ≧ 5 mV (1)
Further, the developer of the present invention includes a core particle formed by using the first fine particles containing the first binder resin and the colorant, and formed on the surface of the core particle. A developer including a shell formed using second fine particles containing one of the second binder resins different from the first binder resin,
The first dispersion containing the first fine particles and the second dispersion containing the second fine particles are mixed to form a mixed dispersion, an aggregating agent is added to the mixed dispersion, and the first dispersion is added. After the fine particles of 1 are selectively agglomerated to form core particles, an aggregating agent and a pH adjuster are added to the mixed dispersion containing the core particles, and the second fine particles are agglomerated on the surface of the core particles. Manufactured by forming a shell,
Each of the first dispersion and the second dispersion has a solid content concentration of 5% by weight, and the zeta potential when aluminum sulfate is added to the solid content by 1% by weight is Z1, When Z2 is satisfied, the absolute value of the difference in zeta potential satisfies the relationship represented by the following formula (1).

15 mV ≧ | Z2-Z1 | ≧ 5 mV (1)

  According to the present invention, a developer having a core-shell structure can be easily produced.

The flow for demonstrating the manufacturing method of the developing agent of this invention is shown.

  Hereinafter, the method for producing a developer of the present invention will be described in more detail with reference to the drawings.

  FIG. 3 shows a flow for explaining the developer manufacturing method of the present invention.

  In the developer production method of the present invention, basically, the first dispersion liquid containing the first fine particles containing the binder resin and the colorant, and at least the first binder resin and the first binder resin Using a second dispersion liquid containing second fine particles containing one of different second binder resins, the first fine particles are aggregated to form core particles, and then the second fine particles are attached to the surface of the core particles. To form a shell to produce a developer.

  In the first dispersion and the second dispersion used in the present invention, when the zeta potential when adding 1 wt% of aluminum sulfate to the solid content is Z1 and Z2, respectively, the difference between the zeta potentials. Is adjusted to satisfy the relationship represented by the following formula (1).

15 mV ≧ | Z2-Z1 | ≧ 5 mV (1)
In the present invention, as shown in the figure, first, a first dispersion and a second dispersion satisfying the above formula (1) are respectively prepared (Act 1, Act 2).

  Next, a mixed dispersion is prepared by combining and mixing the first dispersion and the second dispersion (Act 3). Next, the first fine particles are selectively aggregated by adding an aggregating agent to form core particles (Act 4).

  Thereafter, an aggregating agent and a pH adjusting agent are added, and the second fine particles are selectively aggregated on the surface of the core particles to aggregate the shell (Act 5), thereby obtaining particles having a core-shell structure.

  Furthermore, toner particles are obtained by arbitrarily heating and fusing particles having a core-shell structure, followed by washing (Act 6) and drying (Act 7).

  The developer of the present invention is a developer obtained by the above method, and is formed using the first fine particles containing the first binder resin and the colorant, and substantially consists of the first fine particles. It is formed using core particles and second fine particles formed on the surface of the core particles and containing at least a first binder resin or a second binder resin different from the first binder resin. Includes a shell that becomes

  According to the present invention, the first dispersion and the second dispersion are mixed, and the flocculant and the pH adjuster are sequentially added to the mixed dispersion, thereby forming the core particles and the shell. Can be continuously performed in one mixed dispersion, and a developer having a core-shell structure can be easily obtained.

  In order to agglomerate the fine particles in the dispersion, an aggregating agent such as a metal salt is added, and the zeta potential of the fine particles is brought close to 0 to lower the dispersion stability. The dispersion stability of the fine particles depends on the dispersibility of the fine particles themselves and a dispersant such as a surfactant. As the amount of the surfactant added increases, the absolute value of the zeta potential increases and the dispersion stability of the fine particles increases. For example, by mixing two types of dispersion liquids having different surface active materials, it is possible to make a difference in the amount of decrease in zeta potential due to the addition of the flocculant. Thereby, aggregation can be controlled and only the first fine particles can be selectively aggregated.

  In the present invention, only the core particles are selectively aggregated due to the difference in agglomeration by mixing the fine particle dispersion before adding the flocculant and controlling the dispersion stability of the core particles and the shell particles. A developer having a core-shell structure, that is, a so-called capsule toner is manufactured. By constructing the core-shell structure, the composition of the toner surface becomes uniform, and filming due to suppression of the release agent exposed on the surface, deterioration of chargeability and the like can be prevented, and stable image formation can be performed over a long period of time.

  The present invention produces toner particles having a core-shell structure by controlling the difference in dispersion stability between core particles and shell particles. The toner material particles, that is, the core particles and the shell particles can be applied by a method of manufacturing in an aqueous medium such as an aggregation method or a suspension polymerization method. It is also possible to disperse toner material particles produced by a pulverization method in an aqueous medium. In the agglomeration method, before the agglomeration, a dispersion of resin fine particles that form a shell having a higher dispersibility stability than that of the fine particle dispersion serving as the core is mixed and agglomerated in the dispersion of the fine particles that constitute the core. The agglomeration of the fine particles is advanced to obtain 2 to 10 μm agglomerated particles, and the particles of the dispersion of resin fine particles serving as a shell are not intentionally agglomerated but remain unaggregated. Thereafter, toner particles having a core-shell structure are constructed by reducing the difference in dispersion stability between the dispersion of fine particles serving as a core and the dispersion of resin fine particles serving as a shell by adjusting pH, adding an aggregating agent, and the like.

  As a method for controlling the dispersion stability, it becomes possible by the difference in the amount of the surfactant added when preparing the fine particle dispersion. A zeta potential is used for evaluating the dispersion stability. When the solid content concentration of the first and second dispersions is 5% by weight, respectively, and the zeta potential when adding 1% by weight of aluminum sulfate to the solid content is Z1 and Z2, respectively, the difference in zeta potential Satisfies the relationship represented by the following formula (1).

15 mV ≧ | Z2-Z1 | ≧ 5 mV (1)
If the difference in zeta potential is less than 5 mV, the fine particles that become the shell are taken into the core particles when the fine particles that become the core aggregate, and the core-shell structure cannot be formed.

  When the difference in zeta potential exceeds 15 mV, there is a disadvantage that unaggregated particles that cannot be encapsulated remain because the zeta potential of the shell particles cannot be sufficiently lowered.

  The solid content weight ratio of the second dispersion to the first dispersion is preferably 4/6 ≧ (second dispersion / first dispersion) ≧ 1/9. If (second dispersion / first dispersion) <1/9, the core particle surface is not sufficiently covered, and the composition of the toner particle surface tends to be non-uniform. When 4/6 <(second dispersion / first dispersion), the shell particles are homo-aggregated and the coating layer on the surface of the core particles becomes too thick, so that the effect of the release agent is eliminated and the non-offset region is sufficient. Tend to disappear.

  It is also possible to produce an electrophotographic toner having a multilayer structure of three or more layers by mixing three or more kinds of fine particle dispersions.

  The average volume particle size of the core fine particles can be 2-10 μm. Further, the volume average particle diameter of the fine particles serving as the shell of the second layer can be set to 0.3 to 1.0 μm.

  The first fine particles can be prepared by, for example, a method of subjecting a coarsely pulverized product obtained by melting and kneading a toner particle material containing a binder resin and a colorant to a fine particle by using a mechanical shearing device, or a polymerization method. it can.

  A mold release agent can be added to the first fine particles.

  By adding a release agent to the first fine particles and forming a shell with the second fine particles, it becomes difficult for the release agent to exude on the toner particle surfaces.

  At least a part or all of the second fine particles are made of a binder resin.

  The binder resin used for the first fine particles and the second fine particles may be the same resin material or different resin materials.

  From the viewpoint of storage stability of the toner, the resin glass transition temperature (Tg) in the fine particle dispersion is higher than that of the first binder used in the first dispersion. Is preferably high.

Zeta potential measurement method
The fine particle dispersion solid content concentration is diluted to 5% by weight with ion-exchanged water, and 5% by weight aluminum sulfate is added at 1% by weight to the solid content in the fine particle dispersion. This dispersion is diluted to 5 ppm and the zeta potential is measured. Using a zeta potential measuring device ZEECOM (manufactured by Microtech Nichion Co., Ltd.), the cell position is set to 15 mm and the voltage is set to 70 V, 50 particles are measured at random, and the average value is taken as the zeta potential.

As the materials used in the present invention, all known materials such as resins, colorants, mold release agents and the like can be used. Examples of the binder resin used in the present invention include polystyrene, styrene-butadiene copolymer, styrene.・ Styrenic resins such as acrylic copolymers, polyethylene, polyethylene / polyvinyl acetate copolymers, polyethylene / norbornene copolymers, ethylene / vinyl alcohol copolymers and other ethylene resins, polyester resins, acrylic resins, Examples include phenolic resins, epoxy resins, allyl phthalate resins, polyamide resins, and maleic resins. These resins may be used alone or in combination of two or more.

  The binder resin may preferably have an acid value of 1 or more.

  Examples of the colorant used in the present invention include carbon black, organic or inorganic pigments and dyes. For example, carbon black includes acetylene black, furnace black, thermal black, channel black, ketjen black, and the like. Examples of yellow pigments include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 65, 73, 74, 81, 83, 93, 95, 97, 98, 109, 117, 120, 137, 138, 139, 147, 151, 154, 167, 173, 180, 181, 183, 185, C.I. I. Bat yellow 1, 3, 20, etc. are mentioned. These can be used alone or in combination. Examples of magenta pigments include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 146, 150, 163, 184, 185, 202, 206, 207, 209, 235, C.I. I. Pigment violet 19, C.I. I. Bat red 1, 2, 10, 13, 15, 23, 29, 35, etc. are mentioned. These may be used alone or in combination. Examples of cyan pigments are: C. I. Pigment blue 3, 15, 16, 17, C.I. I. Bat Blue 6, C.I. I. Acid Blue 45 and the like. These may be used alone or in combination.

  Examples of the release agent used in the present invention include aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymer, polyolefin wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, and oxidized polyethylene wax. Oxides of aliphatic hydrocarbon waxes such as these, or their block copolymers, plant waxes such as candelilla wax, carnauba wax, wood wax, jojoba wax, rice wax, beeswax, lanolin, whale wax -Based waxes, mineral waxes such as ozokerite, ceresin, petrolactam, waxes based on fatty acid esters such as montanic ester wax, castor wax, fatty acids such as deoxidized carnauba wax Such as those de-oxidizing a portion or all of the ester, and the like. Further, saturated linear fatty acids such as palmitic acid, stearic acid, montanic acid, or long-chain alkyl carboxylic acids having a long-chain alkyl group, unsaturated fatty acid stearyl alcohols such as brassic acid, eleostearic acid, and parinaric acid Saturated alcohols such as eicosyl alcohol, behenyl alcohol, carnauvir alcohol, seryl alcohol, melyl alcohol, or long chain argyl alcohol having a long chain alkyl group, polyhydric alcohols such as sorbitol, linoleic acid Fatty acid amides such as amides, oleic acid amides, lauric acid amides, methylene bis stearic acid amides, ethylene biscapric acid amides, ethylene bis lauric acid amides, saturated fatty acid bisamides such as hexamethylene bis stearic acid amides, Unsaturated fatty acid amides such as lenbis oleic acid amide, hexamethylene bis oleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide, m-xylene bis stearic acid amide , Aromatic bisamides such as N, N′-distearylisophthalic acid amide, fatty acid metal salts such as calcium stearate, calcium laurate, zinc stearate and magnesium stearate (generally referred to as metal soap), aliphatic carbonization Obtained by hydrogenating waxes grafted with vinyl monomers such as styrene and acrylic acid on hydrogen wax, partially esterified products of fatty acids and polyhydric alcohols such as behenic acid monoglyceride, and vegetable oils and fats. Methyl ester having a hydroxyl group Compounds.

  Examples of the charge control agent for controlling the triboelectric charge amount usable in the present invention include positively chargeable charge control agents such as nigrosine dyes, quaternary ammonium compounds and polyamine resins, and metal-containing azo compounds. Compounds, metal elements such as iron, cobalt, chromium complexes, complex salts, or mixtures thereof, metal-containing salicylic acid derivative compounds can also be used, and metal elements such as zirconium, zinc, chromium, boron complexes, complex salts, or the like Examples include a negatively chargeable charge control agent such as a mixture.

  Examples of the surfactant that can be used in the present invention include anionic surfactants such as sulfate ester, sulfonate, phosphate, and soap, amine salts, quaternary ammonium salts, and the like. Nonionic surfactants such as cationic surfactants, polyethylene glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols can be mentioned. Surfactant may be used individually by 1 type and may use 2 or more types together.

  Examples of the flocculant usable in the aggregation step of the present invention include sodium chloride, calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, sodium sulfate, magnesium sulfate, aluminum chloride, aluminum sulfate, and potassium aluminum sulfate. Metal salts, inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, calcium polysulfide, nonmetal salts such as ammonium chloride and ammonium sulfate, methanol, ethanol, 1-propanol, 2-propanol, 2-methyl- Alcohols such as 2-propanol, 2-methoxy techanol, 2-ethoxy techanol, 2-butoxy techanol, organic solvents such as acetonitrile and 1,4-dioxane, inorganic acids such as hydrochloric acid and nitric acid, formic acid, acetic acid, etc. The organic acid is mentioned.

  The reversal agent that can be used in the present invention may be selected from the surfactants and the flocculants.

  As the neutralizing agent that can be used in the present invention, inorganic bases and amine compounds can be used. Examples of inorganic bases include sodium hydroxide and potassium hydroxide. Examples of amine compounds include dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, propylamine, isopropylamine, dipropylamine, butylamine, isobutylamine, sec-butylamine, monoethanolamine, diethanolamine, triethanolamine, triisopropanolamine. , Isopropanolamine, dimethylethanolamine, diethylethanolamine, N-butyldiethanolamine, N, N-dimethyl-1,3-diaminopropane, N, N-diethyl-1,3-diaminopropane and the like.

  Examples of a method for producing a fine particle dispersion containing at least a binder resin and a colorant and, if necessary, a release agent include use of a mechanical shearing device and a phase inversion emulsification method.

  Any known mechanical shearing device can be used in the present invention. For example, Ultra Thalax (manufactured by IKA Japan), TK auto homomixer (manufactured by Primix), TK pipeline homomixer (manufactured by Primix), TK Philmix (manufactured by Primix), Claremix (M Technic Co., Ltd.), Claire SS5 (M Technic Co., Ltd.), Cavitron (Eurotech Co., Ltd.), Fine Flow Mill (Pacific Kiko Co., Ltd.), Medialess Stirrer, Visco Mill (Imex Co., Ltd.), Apex Mill (Kotobuki) Kogyo Co., Ltd.), Star Mill (Ashizawa, Finetech Co., Ltd.), DCP Super Flow (Nihon Eirich Co., Ltd.), MP Mill (Inoue Seisakusho Co., Ltd.), Spike Mill (Inoue Seisakusho Co., Ltd.), Mighty Mill (Inoue Seisakusho Co., Ltd.) , SC mill (made by Mitsui Mining Co., Ltd.) Miser (Sugino Machine Ltd.), Nanomizer (manufactured by Yoshida Kikai), and a high-pressure impact type dispersing device such as NANO 3000 (manufactured by Bitsubusha).

Examples Hereinafter, the present invention will be described in more detail with reference to examples.

The physical properties of the toner were determined by the following method.

Atomized particle size measurement method
The particle size of the atomized particles was measured using SALD7000 (manufactured by Shimadzu Corporation).

Toner Particle Diameter Measuring Method The toner particle diameter was measured using Maltizer 3 (Beckman Coulter, Inc .: aperture diameter 100 μm).

Preparation of fine particle dispersion A
After mixing 90 parts by weight of a polyester resin (Tg: 50 degrees) as a binder resin, 5 parts by weight of a copper phthalocyanine pigment as a colorant, and 5 parts by weight of an ester wax as a release agent, a biaxial kneader set at a temperature of 120 degrees And kneaded to obtain a kneaded product.

  The obtained kneaded product was coarsely pulverized to a volume average particle size of 1.2 mm using a hammer mill manufactured by Nara Machinery Co., Ltd. to obtain coarse particles.

  The coarse particles were medium pulverized to a volume average particle size of 0.05 mm using a bantam mill manufactured by Hosokawa Micron Corporation to obtain intermediate crushed particles.

40 parts by weight of crushed particles, 0.4 parts by weight of sodium dodecylbenzenesulfonate as an anionic surfactant, 1 part by weight of triethylamine as an amine compound, and 58.6 parts by weight of ion-exchanged water at 160 MPa and 180 degrees with NANO3000. A dispersion (1) having a volume average particle diameter of 400 nm was prepared by treatment.

  It was -27.64 mV when this dispersion liquid zeta potential was measured by the above-mentioned zeta potential measuring method.

Preparation of fine particle dispersion B
After mixing 90 parts by weight of a polyester resin (Tg: 55 degrees) as a binder resin, 5 parts by weight of a copper phthalocyanine pigment as a colorant, and 5 parts by weight of an ester wax as a release agent, a biaxial kneader set at a temperature of 120 degrees And kneaded to obtain a kneaded product.

  The obtained kneaded product was coarsely pulverized to a volume average particle size of 1.2 mm using a hammer mill manufactured by Nara Machinery Co., Ltd. to obtain coarse particles.

  The coarse particles were medium pulverized to a volume average particle size of 0.05 mm using a bantam mill manufactured by Hosokawa Micron Corporation to obtain intermediate crushed particles.

  40 parts by weight of crushed particles, 0.4 parts by weight of sodium dodecylbenzenesulfonate as an anionic surfactant, 1 part by weight of triethylamine as an amine compound, and 58.6 parts by weight of ion-exchanged water at 160 MPa and 180 degrees with NANO3000. A dispersion (1) having a volume average particle diameter of 500 nm was prepared by treatment.

  The dispersion was measured for zeta potential by the zeta potential measurement method and found to be -29.27 mV.

Preparation of fine particle dispersion C
After mixing 90 parts by weight of a polyester resin (Tg: 60 degrees) as a binder resin, 5 parts by weight of a copper phthalocyanine pigment as a colorant, and 5 parts by weight of an ester wax as a release agent, a biaxial kneader set at a temperature of 120 degrees And kneaded to obtain a kneaded product.

  The obtained kneaded product was coarsely pulverized to a volume average particle size of 1.2 mm using a hammer mill manufactured by Nara Machinery Co., Ltd. to obtain coarse particles.

  The coarse particles were medium pulverized to a volume average particle size of 0.05 mm using a bantam mill manufactured by Hosokawa Micron Corporation to obtain intermediate crushed particles.

  40 parts by weight of crushed particles, 0.4 parts by weight of sodium dodecylbenzenesulfonate as an anionic surfactant, 1 part by weight of triethylamine as an amine compound, and 58.6 parts by weight of ion-exchanged water at 160 MPa and 180 degrees with NANO3000. A dispersion (1) having a volume average particle diameter of 450 nm was prepared by treatment.

  The dispersion was measured for zeta potential by the zeta potential measurement method and found to be -29.31 mV.

Preparation of fine particle dispersion D
A polyester resin (Tg: 60 °) as a binder resin was crushed to a volume average particle size of 0.05 mm with a bantam mill manufactured by Hosokawa Micron Corporation to obtain crushed particles. 20 parts by weight of crushed particles, 2 parts by weight of sodium dodecylbenzenesulfonate as an anionic surfactant, 0.5 parts by weight of triethylamine as an amine compound, and 77.5 parts by weight of ion-exchanged water at 160 MPa and 180 degrees with NANO3000 A dispersion (2) having a volume average particle diameter of 100 nm was prepared by treatment.

  The dispersion was measured for zeta potential by the zeta potential measurement method and found to be -35.87 mV.

Preparation of fine particle dispersion E
A polyester resin (Tg: 50 degrees) as a binder resin was medium pulverized to a volume average particle size of 0.05 mm using a bantam mill manufactured by Hosokawa Micron Corporation to obtain intermediate crushed particles. 20 parts by weight of crushed particles, 2 parts by weight of sodium dodecylbenzenesulfonate as an anionic surfactant, 0.5 parts by weight of triethylamine as an amine compound, and 77.5 parts by weight of ion-exchanged water at 160 MPa and 180 degrees with NANO3000 A dispersion (2) having a volume average particle diameter of 110 nm was prepared by treatment.

  The dispersion was measured for zeta potential by the zeta potential measurement method and found to be -36.17 mV.

Preparation of fine particle dispersion F
A dispersion (2) having a volume average particle size of 180 nm was prepared in the same manner as in the fine particle dispersion D except that the amount of the anionic surfactant was changed from 2 parts by weight of sodium dodecylbenzenesulfonate to 0.6 parts by weight. The zeta potential of this dispersion was measured by the above zeta potential measurement method and found to be -32.96 mV.

Preparation of fine particle dispersion G
Dispersion (2) prepared in the same manner as the fine particle dispersion D except that the amount of the anionic surfactant was changed from 2 parts by weight to 0.3 parts by weight of sodium dodecylbenzenesulfonate and having a volume average particle diameter of 200 nm. This dispersion was measured for zeta potential by the above zeta potential measurement method and found to be -30.82 mV.

Preparation of fine particle dispersion H
Dispersion (2) prepared in the same manner as the fine particle dispersion D except that the amount of the anionic surfactant was changed from 2 parts by weight to 2.5 parts by weight of sodium dodecylbenzenesulfonate, and the volume average particle diameter was 100 nm. The zeta potential of this dispersion was measured by the above zeta potential measurement method and found to be −42.32 mV.

Preparation of fine particle dispersion I
A dispersion (2) having a volume average particle diameter of 100 nm was prepared in the same manner as the fine particle dispersion D except that the amount of the anionic surfactant was changed from 2 parts by weight of sodium dodecylbenzenesulfonate to 2.8 parts by weight. The zeta potential of this dispersion was measured by the above zeta potential measurement method and found to be -43.16 mV.

Example 1
20 parts by weight of the fine particle dispersion A, 10 parts by weight of the fine particle dispersion D and 45 parts by weight of ion-exchanged water were mixed, 5 parts by weight of 0.8 wt% HCl aqueous solution was added at 30 degrees as a flocculant, and the temperature was raised to 50 degrees. . Thereafter, 20 parts by weight of a 15% by weight aqueous ammonium chloride solution was added to form a shell layer. In order to control the shape, the temperature was raised to 90 degrees and left for 2 hours.

After cooling, the solid content of the obtained dispersion was repeatedly centrifuged with a centrifuge, the supernatant was removed, and washed with ion-exchanged water until the supernatant had a conductivity of 50 μS / cm. . Thereafter, the toner was dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles.

  After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the surface of the toner particles to obtain a desired toner for electrophotography.

  The volume average particle size of the obtained electrophotographic toner was measured with a Multisizer 3 manufactured by Beckman Coulter, Inc. As a result, it was 5.81 μm.

  The obtained toner was evaluated as follows.

Filming 100K paper was passed through a 6% chart using a copying machine e-STUDIO 4520C manufactured by Toshiba Tec Corporation. Thereafter, a solid image (A3) was output, and the filming width within the drum pitch width was confirmed.

  The case of no filming was evaluated as ◯, the case of less than 5 mm, and the case of 5 mm or more as x.

Charge amount The charge amount under high temperature and high humidity (HH) and low temperature and low humidity (LL) was measured with a powder charge amount measuring device TYPE TB-203 manufactured by Kyocera Chemical Co., Ltd.

The case where HH / LL was 70% or more was evaluated as ◯, the case where it was 50-70% was evaluated as Δ, and the case where it was 50% or less was evaluated as ×.

Non-offset temperature range The non-offset temperature range was examined by remodeling a copying machine e-STUDIO 4520C manufactured by TOSHIBA TEC and deliberately changing the fixing temperature.

  The case where the non-offset temperature range was 40 degrees or more was evaluated as ◯, the case where it was 10-40 degrees was evaluated as Δ, and the case where it was 10 degrees or less as x.

Storability 20 g of toner was left at 50 ° C. for 8 hours, and storability was examined by measuring the amount of toner remaining on a 42 mesh sieve by vibrating for 10 seconds at 50 Hz with a powder tester (manufactured by Hosokawa Micron).

  The case of less than 1 g was evaluated as ◯, the case of 1-4 g was evaluated as Δ, and the case of 4 g or more was evaluated as ×.

  Filming, charge amount, non-offset temperature range, and storage were all good.

  The results are shown in Table 1-1 and Table 1-2 below.

Example 2
15 parts by weight of the fine particle dispersion A, 20 parts by weight of the fine particle dispersion D, and 40 parts by weight of ion-exchanged water were mixed, 5 parts by weight of 0.8 wt% HCl aqueous solution was added as a flocculant at 30 degrees, and the temperature was raised to 50 degrees. . Thereafter, 20 parts by weight of a 15% by weight aqueous ammonium chloride solution was added to form a shell layer. In order to control the shape, the temperature was raised to 90 degrees and left for 2 hours.

After cooling, the solid content of the obtained dispersion was repeatedly centrifuged with a centrifuge, the supernatant was removed, and washed with ion-exchanged water until the supernatant had a conductivity of 50 μS / cm. . Thereafter, the toner was dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles.

  After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the surface of the toner particles to obtain a desired toner for electrophotography.

  The volume average particle size of the obtained electrophotographic toner was measured with a Multisizer 3 manufactured by Beckman Coulter, Inc. As a result, it was 6.32 μm.

When the obtained toner was evaluated, filming, charge amount, non-offset temperature range, and storage stability were good.

  The results are shown in Table 1-1 and Table 1-2 below.

Example 3
22.5 parts by weight of the fine particle dispersion A, 5 parts by weight of the fine particle dispersion D, and 47.5 parts by weight of ion-exchanged water are mixed, and 5 parts by weight of 0.8 wt% HCl aqueous solution is added at 30 degrees as an aggregating agent. The temperature was raised to. Thereafter, 20 parts by weight of a 15% by weight aqueous ammonium chloride solution was added to form a shell layer. In order to control the shape, the temperature was raised to 90 degrees and left for 2 hours.

After cooling, the solid content of the obtained dispersion was repeatedly centrifuged with a centrifuge, the supernatant was removed, and washed with ion-exchanged water until the supernatant had a conductivity of 50 μS / cm. . Thereafter, the toner was dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles.

  After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the surface of the toner particles to obtain a desired toner for electrophotography.

  The volume average particle size of the obtained electrophotographic toner was measured with a Multisizer 3 manufactured by Beckman Coulter, Inc. As a result, it was 5.48 μm.

  When the obtained toner was evaluated, filming, charge amount, non-offset temperature range, and storage stability were good.

  The results are shown in Table 1-1 and Table 1-2 below.

Example 4
20 parts by weight of the fine particle dispersion A, 10 parts by weight of the fine particle dispersion H and 45 parts by weight of ion-exchanged water were mixed, 5 parts by weight of 0.8 wt% HCl aqueous solution was added as a flocculant at 30 degrees, and the temperature was raised to 50 degrees. . Thereafter, 20 parts by weight of a 15% by weight aqueous ammonium chloride solution was added to form a shell layer. In order to control the shape, the temperature was raised to 90 degrees and left for 2 hours.

  After cooling, the solid content of the obtained dispersion was repeatedly centrifuged with a centrifuge, the supernatant was removed, and washed with ion-exchanged water until the supernatant had a conductivity of 50 μS / cm. . Thereafter, the toner was dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles.

  After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the surface of the toner particles to obtain a desired toner for electrophotography.

  The volume average particle size of the obtained toner for electrophotography was measured with a Multisizer 3 manufactured by Beckman Coulter, Inc. As a result, it was 5.27 μm.

When the obtained toner was evaluated, filming, charge amount, non-offset temperature range, and storage stability were good.

  The results are shown in Table 1-1 and Table 1-2 below.

Example 5
20 parts by weight of the fine particle dispersion B, 10 parts by weight of the fine particle dispersion D, and 45 parts by weight of ion-exchanged water were mixed, 5 parts by weight of 0.8 wt% HCl aqueous solution was added as a flocculant at 30 degrees, and the temperature was raised to 50 degrees. . Thereafter, 20 parts by weight of a 15% by weight aqueous ammonium chloride solution was added to form a shell layer. In order to control the shape, the temperature was raised to 90 degrees and left for 2 hours.

After cooling, the solid content of the obtained dispersion was repeatedly centrifuged with a centrifuge, the supernatant was removed, and washed with ion-exchanged water until the supernatant had a conductivity of 50 μS / cm. . Thereafter, the toner was dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles.

  After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the surface of the toner particles to obtain a desired toner for electrophotography.

  The volume average particle size of the obtained toner for electrophotography was measured with a Multisizer 3 manufactured by Beckman Coulter, Inc. As a result, it was 5.49 μm.

When the obtained toner was evaluated, filming, charge amount, non-offset temperature range, and storage stability were good.

  The results are shown in Table 1-1 and Table 1-2 below.

Example 6
20 parts by weight of the fine particle dispersion B, 10 parts by weight of the fine particle dispersion F, and 45 parts by weight of ion-exchanged water were mixed, 5 parts by weight of 0.8 wt% HCl aqueous solution was added at 30 degrees as a flocculant, and the temperature was raised to 50 degrees. . Thereafter, 20 parts by weight of a 15% by weight aqueous ammonium chloride solution was added to form a shell layer. In order to control the shape, the temperature was raised to 90 degrees and left for 2 hours.

  After cooling, the solid content of the obtained dispersion was repeatedly centrifuged with a centrifuge, the supernatant was removed, and washed with ion-exchanged water until the supernatant had a conductivity of 50 μS / cm. . Thereafter, the toner was dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles.

  After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the surface of the toner particles to obtain a desired toner for electrophotography.

  The volume average particle size of the obtained toner for electrophotography was measured with a Multisizer 3 manufactured by Beckman Coulter, Inc. As a result, it was 5.12 μm.

When the obtained toner was evaluated, filming, charge amount, non-offset temperature range, and storage stability were good.

  The results are shown in Table 1-1 and Table 1-2 below.

Comparative Example 1
25 parts by weight of the fine particle dispersion A and 65 parts by weight of ion-exchanged water are mixed, 5 parts by weight of 0.8 wt% HCl aqueous solution is added as a flocculant at 30 degrees, and the temperature is raised to 90 degrees to control the aggregation and shape. And left for 2 hours.

  After cooling, the solid content of the obtained dispersion was repeatedly centrifuged with a centrifuge, the supernatant was removed, and washed with ion-exchanged water until the supernatant had a conductivity of 50 μS / cm. . Thereafter, the toner was dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles.

  After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the surface of the toner particles to obtain a desired toner for electrophotography.

  The volume average particle diameter of the obtained electrophotographic toner was measured with a Multisizer 3 manufactured by Beckman Coulter, Inc. As a result, it was 5.34 μm.

  When the obtained toner was evaluated, the non-offset temperature range was good, but good results were not obtained for filming, charge amount, and storage stability.

  The results are shown in Table 1-1 and Table 1-2 below.

Comparative Example 2
23.8 parts by weight of the fine particle dispersion A, 12.5 parts by weight of the fine particle dispersion D, and 38.7 parts by weight of ion-exchanged water are mixed, and 5 parts by weight of 0.8 wt% HCl aqueous solution is added at 30 degrees as a flocculant. The temperature was raised to 50 degrees. Thereafter, 20 parts by weight of a 15% by weight aqueous ammonium chloride solution was added to form a shell layer. In order to control the shape, the temperature was raised to 90 degrees and left for 2 hours.

After cooling, the solid content of the obtained dispersion was repeatedly centrifuged with a centrifuge, the supernatant was removed, and washed with ion-exchanged water until the supernatant had a conductivity of 50 μS / cm. . Thereafter, the toner was dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles.

  After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the surface of the toner particles to obtain a desired toner for electrophotography.

  The volume average particle size of the obtained electrophotographic toner was measured with a Multisizer 3 manufactured by Beckman Coulter, Inc. As a result, it was 5.66 μm.

When the obtained toner was evaluated, the non-offset temperature range was good, but good results were not obtained for filming, charge amount, and storage stability.

  The results are shown in Table 1-1 and Table 1-2 below.

Comparative Example 3
13.8 parts by weight of the fine particle dispersion A, 22.5 parts by weight of the fine particle dispersion D and 38.7 parts by weight of ion-exchanged water were mixed, and 5 parts by weight of 0.8 wt% HCl aqueous solution was added at 30 degrees as a flocculant. The temperature was raised to 50 degrees. Thereafter, 20 parts by weight of a 15% by weight aqueous ammonium chloride solution was added to form a shell layer. In order to control the shape, the temperature was raised to 90 degrees and left for 2 hours.

After cooling, the solid content of the obtained dispersion was repeatedly centrifuged with a centrifuge, the supernatant was removed, and washed with ion-exchanged water until the supernatant had a conductivity of 50 μS / cm. . Thereafter, the toner was dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles.

  After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the surface of the toner particles to obtain a desired toner for electrophotography.

  The volume average particle size of the obtained electrophotographic toner was measured with a Multisizer 3 manufactured by Beckman Coulter, Inc. As a result, it was 6.15 μm.

When the obtained toner was evaluated, the filming, the charge amount, and the storage stability were good, but the non-offset temperature range was not good.

  The results are shown in Table 1-1 and Table 1-2 below.

Comparative Example 4
20 parts by weight of fine particle dispersion C, 10 parts by weight of fine particle dispersion E, and 45 parts by weight of ion-exchanged water were mixed, 5 parts by weight of 0.8 wt% HCl aqueous solution was added at 30 degrees as an aggregating agent, and the temperature was raised to 50 degrees. . Thereafter, 20 parts by weight of a 15% by weight aqueous ammonium chloride solution was added to form a shell layer. In order to control the shape, the temperature was raised to 90 degrees and left for 2 hours.

  After cooling, the solid content of the obtained dispersion was repeatedly centrifuged with a centrifuge, the supernatant was removed, and washed with ion-exchanged water until the supernatant had a conductivity of 50 μS / cm. . Thereafter, the toner was dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles.

  After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the surface of the toner particles to obtain a desired toner for electrophotography.

  The volume average particle size of the obtained electrophotographic toner was measured with a Multisizer 3 manufactured by Beckman Coulter, Inc. As a result, it was 5.61 μm.

When the obtained toner was evaluated, filming, charge amount, and non-offset temperature range were good, but good storage stability was not obtained.

  The results are shown in Table 1-1 and Table 1-2 below.

Comparative Example 5
20 parts by weight of the fine particle dispersion A, 10 parts by weight of the fine particle dispersion G, and 45 parts by weight of ion-exchanged water were mixed, 5 parts by weight of 0.8 wt% HCl aqueous solution was added as a flocculant at 30 degrees, and the temperature was raised to 50 degrees. . Thereafter, 20 parts by weight of a 15% by weight aqueous ammonium chloride solution was added to form a shell layer. In order to control the shape, the temperature was raised to 90 degrees and left for 2 hours.

  After cooling, the solid content of the obtained dispersion was repeatedly centrifuged with a centrifuge, the supernatant removed, and washed with ion-exchanged water until the supernatant had a conductivity of 50 μS / cm. . Thereafter, the toner was dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles.

  After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the surface of the toner particles to obtain a desired toner for electrophotography.

  The volume average particle diameter of the obtained electrophotographic toner was measured with a Multisizer 3 manufactured by Beckman Coulter, Inc. As a result, it was 5.76 μm.

  When the obtained toner was evaluated, the non-offset temperature range was good, but good results were not obtained for filming, charge amount, and storage stability.

  The results are shown in Table 1-1 and Table 1-2 below.

Comparative Example 6
20 parts by weight of the fine particle dispersion A, 10 parts by weight of the fine particle dispersion I and 45 parts by weight of ion-exchanged water were mixed, 5 parts by weight of 0.8 wt% HCl aqueous solution was added as a flocculant at 30 degrees, and the temperature was raised to 50 degrees. . Thereafter, 30 parts by weight of a 15% by weight ammonium chloride aqueous solution was added, but a shell layer could not be formed.

The results are shown in Table 1-1 and Table 1-2 below.

Japanese Patent Laid-Open No. 63-282275 JP-A-6-250439 JP 2003-31068 A JP-A-10-73955 JP-A-10-26842 JP 2005-99081 A

Claims (6)

One of the first dispersion containing the first fine particles containing the first binder resin and the colorant, and at least one of the first binder resin and the second binder resin different from the first binder resin Mixing with a second dispersion containing second microparticles containing a mixture to form a mixed dispersion;
After adding a flocculant to the mixed dispersion to selectively agglomerate the first microparticles to form core particles;
A method for producing a developer, comprising adding a pH adjuster to the mixed dispersion containing the core particles, aggregating the second fine particles on the core particle surfaces, and forming a shell.
Each of the first dispersion and the second dispersion has a solid content concentration of 5% by weight, and 5% by weight of aluminum sulfate is 1% by weight with respect to the solids in the dispersion. %, After the addition, the zeta potential when the dispersion is 5 ppm is Z1 and Z2, respectively, and the absolute value of the difference in zeta potential satisfies the relationship represented by the following formula (1).
15 mV ≧ | Z2-Z1 | ≧ 5 mV (1)   The method according to claim 1, wherein a weight ratio of the first dispersion to the second dispersion (first dispersion / second dispersion) is from 6/4 to 9/1. .   Each of the first dispersion and the second dispersion further includes a surfactant, and the weight of the surfactant in the second dispersion is greater than the weight of the surfactant in the first dispersion. 3. A method according to claim 1 or 2, wherein   4. The method according to claim 1, wherein the first fine particles have a volume average particle diameter of 0.3 to 1.0 μm.   The method according to claim 1, wherein the developer has a volume average particle size of 3 to 10 μm.   The said 2nd dispersion liquid contains the said 2nd binder resin, The glass transition temperature of this 2nd binder resin is higher than the glass transition temperature (Tg) of the said 1st binder resin. the method of.

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