WO2013137365A1 - Procédé de fabrication de particules, particules, encre en poudre, révélateur, et imageur - Google Patents

Procédé de fabrication de particules, particules, encre en poudre, révélateur, et imageur Download PDF

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Publication number
WO2013137365A1
WO2013137365A1 PCT/JP2013/057111 JP2013057111W WO2013137365A1 WO 2013137365 A1 WO2013137365 A1 WO 2013137365A1 JP 2013057111 W JP2013057111 W JP 2013057111W WO 2013137365 A1 WO2013137365 A1 WO 2013137365A1
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WIPO (PCT)
Prior art keywords
pressure
particles
plastic material
toner
melt
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PCT/JP2013/057111
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English (en)
Inventor
Keiko Osaka
Chiaki Tanaka
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Ricoh Company, Ltd.
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Publication of WO2013137365A1 publication Critical patent/WO2013137365A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/12—Powdering or granulating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B9/00—Making granules
    • B29B9/10—Making granules by moulding the material, i.e. treating it in the molten state
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/0802—Preparation methods
    • G03G9/081—Preparation methods by mixing the toner components in a liquefied state; melt kneading; reactive mixing
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/0821—Developers with toner particles characterised by physical parameters
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08742—Binders for toner particles comprising macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • G03G9/08753—Epoxyresins
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08742—Binders for toner particles comprising macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • G03G9/08755—Polyesters
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08742—Binders for toner particles comprising macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • G03G9/08764—Polyureas; Polyurethanes
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08742—Binders for toner particles comprising macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • G03G9/08766—Polyamides, e.g. polyesteramides
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08784—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775
    • G03G9/08797—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775 characterised by their physical properties, e.g. viscosity, solubility, melting temperature, softening temperature, glass transition temperature
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2367/00—Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
    • C08J2367/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds

Definitions

  • the present invention relates to a method for producing particles using a compressive fluid.
  • thermoplastic resins and thermosetting resins various products in the shape of particles are produced by processing resins, such as thermoplastic resins and thermosetting resins, depending on the properties thereof.
  • a method for producing a toner as one example of particles, in which a formulation including a resin and additive is melted and kneaded, followed by cooling, solidification, pulverization, and classification (see PTL l).
  • fine powder generated by pulverization is mixed in the toner, and therefore basic properties of the toner, such as charging
  • a method for producing a toner without pulverizing a resin or the like disclosed is a method for emulsifying and dispersing a colorant resin solution (see PTL 2) .
  • a colorant resin solution containing a polyester-based resin, a colorant, and a water-insoluble organic solvent is emulsified and dispersed in water to form an O/W emulsion, followed by removing the organic solvent to color resin particles, which are then aggregated to produce toner particles.
  • a toner is produced in this method, however, there is a problem that a large load is applied to the environment as the organic solvent is used.
  • a method for producing a toner without using an organic solvent disclosed is a method using liquid carbon dioxide (see PTL 3) .
  • a resin melt of polyester and liquid carbon dioxide are mixed by a static mixer, and the obtain mixture is discharged from a nozzle provided at an edge of the static mixer into the atmosphere having the
  • the present invention aims to provide a method for producing particles, which can homogeneously mix a compressive fluid and a pressure plastic material, and reduce a viscosity of a melt obtained by melting the pressure plastic material, so that particles are easily formed.
  • a method for producing particles containing:
  • melt has a viscosity of 500 mPa s or lower at temperature and pressure as the melt is jetted.
  • the present invention can provide a method for producing particles, which can homogeneously mix a compressive fluid and a pressure plastic material, and reduce a viscosity of a melt obtained by melting the pressure plastic material, so that particles are easily formed.
  • FIG. 1 is a graph illustrating a relation between glass transition temperature (vertical axis) of a pressure plastic material, and pressure (horizontal axis).
  • FIG. 2 is a general phase diagram showing the state of a substance varying depending on pressure and temperature conditions.
  • FIG. 3 is a phase diagram which defines a compressive fluid.
  • FIG. 4 is a schematic diagram illustrating one example of an apparatus for producing particles.
  • FIG. 5 is a schematic diagram illustrating one example of an apparatus for producing particles.
  • FIG. 6 is a schematic diagram illustrating one example of an apparatus for producing particles.
  • FIG. 7 is a schematic diagram illustrating one example of the image forming apparatus of the present invention. Description of Embodiments
  • the method for producing particles of the present invention contains a melting step, and a particle-forming step, and may further contain other steps, if necessary.
  • the viscosity of the melt at temperature and pressure as the melt is jetted is preferably 500 mPa s or lower, more preferably 300 mPa s or lower, and even more preferably 100 mPa s or lower.
  • the viscosity thereof is particularly desirable
  • the viscosity of the melt is greater than 500 mPa s, it may be difficult to form particles, and coarse particles, fibrous products, foam, and cohesion tend to be formed.
  • the temperature and pressure as the melt of the pressure plastic material is jetted means temperature and pressure of the melt supplied to a nozzle at the time of jetting in the particle forming step.
  • the viscosity can be measured, for example, by charging a high pressure cell with a sample composed of the pressure plastic material and the compressive fluid (high pressure carbon dioxide) and performing a measurement by means of a vibrating
  • viscometer (XL 7) manufactured by Hydramotion Ltd. under the conditions, 160°C and 2 MPa. Specifically, the measurement of the viscosity is performed in the following manner. The sample is set in a measuring part, and the sample is controlled to have the temperature and pressure when the melt of the pressure plastic material is jetted (e.g., 160°C and 2 MPa). When the viscosity of the sample becomes constant, such viscosity is determined as a viscosity at such temperature and pressure.
  • melted means the state where raw materials, such as a pressure plastic material, are plasticized and liquidized as well as swollen, by being in contact with the compressive fluid.
  • the raw materials are materials for producing particles, and materials that will be constitutional components of the particles.
  • the melting step is bringing a compressive fluid and a pressure plastic material into contact with each other to melt the pressure plastic material.
  • raw materials such as a pressure plastic material, for use in the method for producing particles of the present invention will be explained.
  • FIG. 1 is a graph depicting the relation between the glass transition temperature (vertical axis) of the pressure plastic material, and pressure (horizontal axis).
  • the pressure plastic material is a material having a characteristic that the glass transition temperature (Tg) thereof reduces as pressure is applied.
  • the pressure plastic material is a material that is plasticized upon application of pressure without application of heat.
  • the pressure plastic material is plasticized at temperature lower than the glass transition temperature of the pressure plastic material as measured by atmospheric pressure, once pressure is applied to the pressure plastic material by bringing the pressure plastic material in contact with a compressive fluid.
  • FIG. 1 depicts the relation between grass transition temperature (vertical axis) of polystyrene, as an example of the pressure plastic material, and pressure (horizontal axis) in the presence of carbon dioxide.
  • FIG. 1 there is a correlation between the glass transition temperature of the polystyrene and pressure, and the graph shows negative gradient.
  • the gradient varies depending on the type, composition, and molecular weight of the pressure plastic material.
  • the gradient is -9 °C/MPa; when the pressure plastic material is a styrene-acryl resin, the gradient is -9 °C/MPa> ' when the pressure plastic material is a noncrystalline polyester resin, the gradient is -8 °C/MPa; when the pressure plastic material is crystalline polyester, the gradient is -2 °C/MPa; when the pressure plastic material is a polyol resin, the gradient is -8 °C/MPa; when the pressure plastic material is a urethane resin, the gradient is -7 °C/MPa> " when the pressure plastic material is a polyarylate resin, the gradient is -11 °C/MPa; and when the pressure plastic resin is a polycarbonate resin, the gradient is -10 °C/MPa.
  • the gradient can be determined based in the following manner. Specifically, grass transition temperature of the pressure plastic material is measured by means of high pressure calorimeter C-80, manufactured by SETARAM Instrumentation with varying pressure applied, and the gradient is determined based on the results from the measurement. In the measurement above, a sample is set in a high pressure measuring cell, the cell is then purged with carbon dioxide, followed by applying pressure to give the predetermined pressure to measure glass transition
  • the gradient can be determined based on the variation of the glass transition
  • temperature relative to the pressure is appropriately selected depending on the intended purpose without any limitation, but it is preferably -1 °C/MPa or less, more preferably -5 °C/MPa or less, and eve more preferably -10 °C/MPa or less. Note that, there is no lower limit for the gradient. When the gradient is greater than -1 °C/MPa, plasticization is sufficient with
  • the pressure plastic material is preferably a pressure plastic material that has a viscosity of 500 mPa s or lower with pressure of 30 MPa or lower.
  • the viscosity of the pressure plastic material may be made 500 mPa s or lower at 30 MPa or lower, by applying heat of the temperature equal to or lower than the melting point to the pressure plastic material at ambient pressure.
  • the carbonyl structure is formed of a n-bond between oxygen having high electronegativity, and carbon, and has high reactivity as the n-bond electron is strongly attracted to the oxygen, the oxygen is negatively polarized, and the carbon is positively polarized.
  • the pressure plastic material having at least a carbonyl structure is
  • the pressure plastic material is not limited to those having a carbonyl structure, and can be appropriately selected depending on the intended purpose.
  • examplesthereof include a vinyl resin, an epoxy resin, a phenol resin, an aliphatic or alicyclic hydrocarbon resin, an aromatic petroleum resin, chlorinated paraffin, paraffin wax, polyethylene, and polypropylene. These may be used alone, or in combination.
  • the polyester resin is appropriately selected depending on the intended purpose without any limitation, and examples thereof include modified polyester, unmodified polyester, non-crystalline polyester, crystalline polyester, and polylactic acid resin.
  • the polylactic acid resin is appropriately selected depending on the intended purpose without any limitation, and examples thereof include an L-form, D-form, or racemic body polylactic acid resin, a polylactic acid resin of a stereo complex, and polylactic acid-based block copolymer.
  • the polyol resin is appropriately selected depending on the intended purpose without any limitation.
  • a polyether polyol resin having an epoxy skeleton is used, and preferred is a polyol resin obtained through a reaction of (i) an epoxy resin, (ii) a bivalent phenol alkylene oxide adduct, or glycidyl ether thereof, and (iii) a compound having an active hydrogen reactive with an epoxy group.
  • the vinyl resin is appropriately selected depending on the intended purpose without any limitation.
  • examples thereof include - styrene and a polymer of a substituted product thereof, such as polystyrene, poly(p -chlorostyrene) , and polyvinyl toluene; a styrene-based copolymer, such as a styrene-p -chlorostyrene copolymer, a styrene-propylene copolymer, a styrene-vinyltoluene copolymer, a styrene -vinylnaphthalene copolymer, a
  • styrene -methyl acrylate copolymer a styrene-ethyl acrylate copolymer, a styrene-butyl acrylate copolymer, a styrene -octyl acrylate copolymer, a styrene-methyl methacrylate copolymer, a styrene -ethyl methacrylate copolymer, a styrene-butyl
  • methacrylate copolymer a styrene-a-chloromethyl methacrylate copolymer, a styrene -acrylonitrile copolymer, a
  • styrene -vinylmethylketone copolymer a styrene -butadiene copolymer, a styrene-isoprene copolymer, a
  • styrene-acrylonitrile -indene copolymer a styrene-maleic acid copolymer, and a styrene-maleic acid ester copolymer
  • a polymer of a monomer e .g. , polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, vinyl propionate, (meth)acrylamide , vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl methyl ketone, N-vinyl
  • the urethane resin is appropriately selected depending on the intended purpose without any limitation.
  • the particles to be produced by the method of the present invention are a toner
  • raw materials such as a colorant, a surfactant, a dispersant, a releasing agent, a charge controlling agent, and crystalline polyester, will be explained hereinafter.
  • the colorant is not particularly limited and may be appropriately selected from known dyes and pigments depending on the intended purpose.
  • the pigment include carbon blacks, nigrosine dyes, iron black, Naphthol Yellow S, Hansa Yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, yellow ocher, chrome yellow, Titan Yellow, Polyazo Yellow, Oil Yellow, Hansa Yellow (GR, A, RN, R), Pigment Yellow L,
  • examples of the dye include C.I. SOLVENT YELLOW (6, 9, 17, 31, 35, 100, 102, 103, 105), C.I. SOLVENT ORANGE (2, 7, 13, 14, 66), C.I. SOLVENT RED (5, 16, 17, 18, 19, 22, 23, 143, 145, 146, 149, 150, 151, 157, 158), C.I. SOLVENT VIOLET (31, 32, 33, 37), C.I. SOLVENT BLUE (22, 63, 78, 83 to 86, 191, 194, 195, 104), C.I. SOLVENT GREEN (24, 25), and C. I. SOLVENT BROWN (3, 9),. These may be used alone or in combination.
  • examples of a commercial product of the dye include Aizen SOT dyes such as Yellow 1, 3, 4, Orange- 1, 2, 3, Scarlet- 1, Red- 1, 2, 3, Brown-2, Blue- 1,2, Violet- 1, Green- 1, 2, 3, and Black- 1, 4, 6, 8 (manufactured by Hodogaya Chemical Co., Ltd.); Sudan dyes such as Yellow l46, 150, Orange-220, Red-290, 380, 460, and Blue-670 (manufactured by BASF); Diaresin
  • Brown-GR #416, Oil Color Green-BG, #502, Oil Color Blue-BOS, UN, and Oil Color Black HBB, #803, EB, EX (manufactured by Orient Chemical Industries, Ltd.); Sumiplast Blue-GP, OR, Sumiplast Red-FB, 3B, and Sumiplast Yellow FL7G, GC
  • the amount of the colorant is not particularly limited and may be appropriately selected depending on a coloring degree. It is preferably 1 part by mass to 50 parts by mass, relative to 100 parts by mass of the pressure plastic material.
  • raw materials of the toner preferably include a surfactant.
  • the surfactant is appropriately selected depending on the intended purpose without any limitation, provided that it contains, in a molecular thereof, a site having affinity to the compressive fluid, and a site having affinity to the toner.
  • the surfactant is preferably a fluorosurfactant, a silicone surfactant, or a compound including a group having an affinity to carbon dioxide, such as a compound having a bulky functional group (e.g., a carbonyl group, a short-chain hydrocarbon group, and a propylene oxide group).
  • a fluorosurfactant e.g., a fluorosurfactant, a silicone surfactant, or a compound including a group having an affinity to carbon dioxide, such as a compound having a bulky functional group (e.g., a carbonyl group, a short-chain hydrocarbon group, and a propylene oxide group).
  • a fluorosurfactant preferred are a fluorosurfactant, a silicone surfactant, a carbonyl group-containing compound, and a polyethylene glycol (PEG) group-containing compound.
  • These surfactants may be oligomers, or polymers.
  • a compound having a C 1-C30 perfluoroalkyl group is preferably used.
  • a high molecular weight fluorosurfactant is preferable, as it has excellent surface activating properties, and excellent charging ability and durability as contained in a toner.
  • structural units of the fluorosurfactant is represented with the following formulae (l- l) and (1-2). H
  • Ri is a hydrogen atom or a C1 -C4 lower alkyl group (e.g., a methyl group, an ethyl group, a propyl group, an isopropyl group, a n-butyl group, a secbutyl group, and a tert-butyl group).
  • a C1 -C4 lower alkyl group e.g., a methyl group, an ethyl group, a propyl group, an isopropyl group, a n-butyl group, a secbutyl group, and a tert-butyl group.
  • R2 is an alkylene group (e.g., a methylene group, an ethylene group, a propylene group, an isoprene group, a 2-hydroxypropylene group, a butylene group, and a 2-hydroxybutylene group).
  • alkylene group e.g., a methylene group, an ethylene group, a propylene group, an isoprene group, a 2-hydroxypropylene group, a butylene group, and a 2-hydroxybutylene group.
  • Rf is a C 1-C30 perfluoroalkyl group or perfluoroalkenyl group.
  • the preferable embodiment is a fluorosurfactant where R 1 is a hydrogen atom or a methyl group, R2 is a methylene group or an ethylene group, and Rf is a C7-C 10 perfluoroalkyl group.
  • R 1 is a hydrogen atom or a methyl group
  • R2 is a methylene group or an ethylene group
  • Rf is a C7-C 10 perfluoroalkyl group.
  • a plurality of each structural unit of the formulae (l ⁇ l) and (1-2) are bonded to each other to form an oligomer or polymer.
  • a homopolymer, a block copolymer or a random copolymer may be formed.
  • Each terminal of the oligomers or polymer is
  • the silicone surfactant is not particularly limited, as long as it is a compound having a siloxane bond, and it may be a low molecular weight compound or a high molecular weight compound. Among them, preferred is a compound having a
  • the silicone surfactant may be a homopolymer compound, a block copolymer compound, or a random copolymer compound, in view of an affinity to a toner.
  • R3 is a hydrogen atom, or a C 1-C4 lower alkyl group; n represents a number for repeating! and R 4 is a hydrogen atom, a hydroxyl group, or a C 1-C10 alkyl group.
  • the carbonyl group-containing compound is appropriately selected depending on the intended purpose without any limitation, and examples thereof include aliphatic polyester, polyacrylate, and an acrylic acid resin.
  • Examples thereof include a PEG group-containing polyacrylate, and polyethylene glycol resin.
  • a vinyl monomer e.g., an Rf group-containing vinyl monomer, a PDMS group -containing vinyl monomer, a PEG group-containing vinyl monomer
  • a vinyl monomer e.g., an Rf group-containing vinyl monomer, a PDMS group -containing vinyl monomer, a PEG group-containing vinyl monomer
  • vinyl monomer examples include a styrene monomer, an acrylate monomer, and a methacrylate monomer. These vinyl monomers are commercially readily available, and the vinyl monomer is appropriately selected from these vinyl monomers.
  • a compound in which a Rf group, PDMS group, or PEG group forms a main chain of an oligomers or polymer, and a COOH group, OH group, amino group, or pyrrolidone skeleton is introduced into a side chain thereof may be used.
  • the fluorine group-containing surfactant is synthesized by polymerizing a fluorine-based vinyl monomer in a fluorine-based solvent, such as HCFC225.
  • a fluorine-based solvent such as HCFC225.
  • the fluorine group-containing surfactant may be synthesized by polymerizing a fluorine-based vinyl monomer using supercritical carbon dioxide as a solvent, instead of HCFC225.
  • various raw materials having a structure similar to a compound having a perfluoroalkyl group are commercially available (see a catalog of AZmax Corporation), and various surfactants can be obtained using these commercial products.
  • a method described in "Handbook of fluororesin” (edited by Takaomi Satokawa, published by Nikkan Kogyo Shimbun Ltd.) pp. 730 to 732, may be used.
  • the silicone surfactant can be obtained through a vinyl polymerizable monomer, which is a raw material of the surfactant.
  • a supercritical fluid preferably supercritical carbon dioxide
  • a solvent may be used as a solvent.
  • various compounds each having the structure similar to polydimethylsiloxane are commercially available (for example, see a catalog of AZmax Corporation), and the silicone surfactant may be obtained using any of these commercial products.
  • MONASIL-PCA manufactured by Croda Japan K.K.
  • MONASIL-PCA exhibits excellent properties for forming particles.
  • An amount of the surfactant in the raw materials of the toner is appropriately selected depending on the intended purpose without any limitation, but it is preferably 0.01% by mass to 30% by mass, more preferably 0.1% by mass to 20% by mass.
  • the dispersant is appropriately selected depending on the intended purpose without any limitation, and examples thereof include organic particles, and inorganic particles. Among them, preferred are acryl-modified inorganic particles,
  • silicone-modified inorganic particles fluorine-modified inorganic particles, fluorine-containing organic particles, and silicone organic particles. Particularly preferred is acryl-modified inorganic particles.
  • These dispersants are preferably selected from those dissolved in the compressive fluid.
  • the organic particles are appropriately selected
  • examples thereof include a silicone-modified product of acrylic particles that are insoluble in a supercritical fluid, and a fluorine-modified product of acrylic particles that are insoluble in a supercritical fluid.
  • the inorganic particles are appropriately selected depending on the intended purpose without any limitation, and examples thereof include- polyvalent metal phosphate, such as calcium phosphate, magnesium phosphate, aluminum phosphate, and zinc phosphate! carbonate, such as calcium carbonate, and magnesium carbonate; inorganic salt such as calcium
  • metasilicate calcium sulfate, barium sulfate
  • inorganic oxide such as calcium hydroxide, magnesium hydroxide, aluminum hydroxide, silica, titanium oxide, bentonite, and alumina.
  • silica is preferable .
  • Examples of the acryl-modified inorganic particles include inorganic particles in which a residual OH group present on a surface of each inorganic particle is modified with a silane coupling agent containing a fluorine atom.
  • reaction formula below illustrates an example of silica which is subjected to surface modification using
  • the acryl-modified silica obtained by the above-described method has a high affinity to supercritical carbon dioxide with its Si portion, and a high affinity to a toner with its acrylate portion.
  • silica may be subjected to a surface modification in other methods, without using the reaction formula above, provided that the purpose is the same.
  • silane coupling agent containing a fluorine atom Specific examples of the silane coupling agent containing a fluorine atom are listed below ⁇
  • An amount of the dispersant in the raw materials of the toner is appropriately selected depending on the intended purpose without any limitation, but it is preferably 0.1% by mass to 30% by mass, more preferably 0.2% by mass to 20% by mass.
  • the dispersant is preferably used alone, but the dispersant may be used in combination with another surfactant for the purpose of controlling particle diameters of a toner, or appropriately adjusting charging properties of a toner.
  • the releasing agent is appropriately selected depending on the intended purpose without any limitation, and examples thereof include wax.
  • examples of the wax include low molecular weight polyolefin wax, synthesized hydrocarbon wax, natural wax petroleum wax, higher fatty acid and metal salt thereof, higher fatty acid amide, and various modified wax thereof. These may be used alone, or in combination.
  • low molecular weight polyolefin wax examples include low-molecular weight polyethylene wax and
  • low-molecular weight polypropylene wax examples include Fischer-Tropsh wax.
  • Examples of the natural wax include bee wax, carnauba wax candelilla wax rice wax and montan waxes.
  • Examples of the petroleum wax include paraffin wax and microcrystalline waxes.
  • Examples of the high fatty acid include stearic acid, palmitic acid and myristic acid.
  • a melting point of the releasing agent is appropriately selected depending on the intended purpose without any
  • the melting point of the releasing agent is lower than 40°C, the wax may adversely affect heat resistant storage stability of a toner.
  • the melting point of the releasing agent is higher than 160°C, it is likely that cold offset may occur during a
  • the cold offset is a phenomenon that part of a toner image is removed by electrostatic force in a thermal fixing system, as the toner is not sufficiently melted at an interface with a sheet. It is also called as low temperature offset.
  • An amount of the releasing agent is appropriately selected depending on the intended purpose without any limitation, but it is preferably 1 part by mass to 20 parts by mass, more preferably 3 parts by mass to 15 parts by mass, relative to 100 parts by mass of the pressure plastic material.
  • an effect of the releasing agent may not be exhibited sufficiently.
  • the amount thereof is greater than 20 parts by mass, heat resistant storage stability of a toner may be impaired.
  • the charge controlling agent is appropriately selected depending on the intended purpose without any limitation, but it is preferably a colorless material or a material having a color close to white, because a colored material may adversely affect the intended color tone of a toner.
  • the charge controlling agent include nigrosine dye, triphenylmethane dye, chrome-containing metal complex dye, molybdic acid chelate pigment, rhodamine dye, alkoxy amine, quaternary ammonium salt (including fluoride-modified quaternary ammonium salt), alkylamide, phosphorus or compound thereof, tungsten or compound thereof, fluorine-containing surfactant, metal salt of salicylic acid, and metal salt of a salicylic acid derivative. These may be used alone or in combination. Among them, preferred are metal salt of salicylic acid and metal salt of a salicylic acid derivative.
  • the metal used for the metal salt is appropriately selected depending on the intended purpose without any limitation, and examples thereof include aluminum, zinc, titanium, strontium, boron, silicon, nickel, iron, chrome, and zirconium.
  • controlling agent include : quaternary ammonium salt BONTRON P-51, oxynaphthoic acid metal complex E-82, salicylic metal complex E-84, phenolic condensate E-89 (manufactured by Orient Chemical Industries Ltd.); molybdenum complex of quaternary ammonium salt TP-302 and TP-415, and metal complex of salicylic acid TN- 105 (manufactured by Hodogaya Chemical Co., Ltd.); quaternary ammonium salt copy charge PSY VP2038, triphenylmethane derivatives copy blue PR, quaternary
  • An amount of the charge controlling agent is appropriately selected depending on the intended purpose without any limitation, but it is preferably 0.5 parts by mass to 5 parts by mass, more preferably 1 part by mass to 3 parts by mass, relative to 100 parts by mass of the pressure plastic material. When the amount thereof is smaller than 0.5 parts by mass, the charging properties of a toner may be impaired.
  • the crystalline polyester is appropriately selected depending on the intended purpose without any limitation, but it is preferably crystalline polyester having a sharp molecular weight and a low molecular weight in view of excellent low temperature fixing ability of a resulting toner. More preferred is the crystalline polyester having a peak in the range of 3.5 to 4.0 in a molecular weight M distribution curve of a
  • o-dichlorobenzene soluble component as measured by GPC, where a peak width is 1.5 or less, and a horizontal axis is log(M) and a vertical axis is % by mass, having a weight molecular weight (Mw) of 1,000 to 30,000, a number average molecular weight (Mn) of 500 to 6,000, and Mw/Mn of 2 to 8.
  • Mw weight molecular weight
  • Mn number average molecular weight
  • Mw/Mn Mw/Mn of 2 to 8.
  • a melting point and Fl/2 temperature of the crystalline polyester are appropriately selected depending on the intended purpose without any limitation, but they are preferably low, as long as heat resistant storage stability is not impaired.
  • the DSC endothermic peak temperature thereof is more preferably 50°C to 150°C.
  • the F1/2 temperature is measured as follows.
  • a sample with a volume of 1 cm 2 is melted and allowed to flow using a elevated flow tester CFT-500 (manufactured by Shimadzu Corporation) under the following conditions: diameter of die: 1 mm> ' pressure applied: 10 kg/cm 2 ; and heating rate: 3°C/min.
  • the temperature, at which half of the amount of the sample that has flowed from the flow starting time to the flow ending time is considered to have flowed is defined as the Fi 2
  • the melting temperature and the Fi 2 temperature are lower than 50°C, the heat-resistant storage stability may be degraded, and blocking may readily occur even at internal temperature of the developing device.
  • the melting temperature and the F1/2 temperature are higher than 150°C, sufficient low temperature fixing ability may not be obtained because the minimum fixing temperature becomes high.
  • An acid value of the crystalline polyester is appropriately selected depending on the intended purpose without any limitation, but it is preferably 5 mgKOH/g or greater in view of an affinity between paper and the resin, and low temperature fixing ability of a resulting toner, and more preferably 10 mgKOH/g or greater. Moreover, an acid value of the crystalline polyester is preferably 45 mgKOH/g or less in view of hot offset resistance of a toner.
  • a hydroxyl value of the crystalline polyester is appropriately selected depending on the intended purpose without any limitation, but it is preferably 0 mgKOH/g to 50 mgKOH/g in view of low temperature fixing ability and charging properties of a resulting toner, and more preferably 5 mgKOH/g to 50 mgKOH/g.
  • An amount of the crystalline polyester is appropriately selected depending on the intended purpose without any limitation, but it is preferably 0 parts by mass to 900 parts by mass, more preferably 0.5 parts by mass to 500 parts by mass, and even more preferably 1 part by mass to 100 parts by mass, relative to 100 parts by mass of the pressure plastic material.
  • the amount thereof is smaller than 1 part by mass, low temperature fixing ability of a toner may not be achieved.
  • the amount thereof is greater than 900 parts by mass, the hot offset resistance of a toner may be impaired.
  • -Other Components Other components usable in combination with the pressure plastic material are appropriately selected depending on the intended purpose without any limitation, and examples thereof include a flow improving agent, and a cleaning improving agent.
  • the flow improving agent is an agent that improves hydrophobic properties of a toner through a surface treatment with the agent, and is capable of preventing degradation of flowability or charging properties of the toner even in high humidity environments.
  • Examples of the flow improving agent include a silane coupling agent, a sililating agent, a silane coupling agent having a fluorinated alkyl group, an organotitanate coupling agent, an aluminum-based coupling agent, silicone oil, and modified silicone oil.
  • the cleaning improving agent is an agent added to the toner material to remove the developer remained on a
  • the cleaning improving agent examples include ⁇ fatty acid (e.g. stearic acid) metal salt, such as zinc stearate, and calcium stearate, ' and polymer particles prepared by soap-free emulsion polymerization, such as polymethyl methacrylate particles, and polystyrene particles.
  • fatty acid e.g. stearic acid
  • metal salt such as zinc stearate, and calcium stearate
  • polymer particles prepared by soap-free emulsion polymerization such as polymethyl methacrylate particles, and polystyrene particles.
  • polymer particles preferred are polymer particles having a relatively narrow particle size distribution, and more preferred are polymer particles having the volume average particle diameter of 0.01 ⁇ to 1 ⁇ .
  • FIG. 2 is a phase diagram illustrating a state of a substance depending on temperature and pressure.
  • FIG. 3 is a phase diagram which defines a
  • the compressive fluid has characteristics that it is fast in mass transfer and heat transfer, is low in viscosity, and can continuously greatly change the density, dielectric constant, solubility parameter, free volume and the like by changing the temperature and pressure. Since the compressive fluid has an extremely small surface tension compared to those of organic solvents, the compressive fluid can follow a minute undulation (surface) to wet the surface with the compressive fluid.
  • the compressive fluid can be easily separated from a product, such as a toner, by returning the pressure to normal pressure, and therefore the compressive fluid can be recycled. Accordingly, the method for producing particles of the present invention can reduce environmental load due to the production, compared to the production using water or an organic solvent.
  • the "compressive fluid” refers to a substance present in any one of the regions (l), (2) and (3) of FIG. 3 in the phase diagram of FIG. 2.
  • the substance is known to have extremely high density and show different behaviors from those shown at normal temperature and normal pressure.
  • the substance present in the region (l) is a supercritical fluid.
  • the supercritical fluid is a fluid that exists as a
  • noncondensable high-density fluid at a temperature and a pressure exceeding the corresponding critical points, which are limiting points at which a gas and a liquid can coexist. Also, the supercritical fluid does not condense even when compressed, and exists at critical temperature or higher and critical pressure or higher.
  • the substance present in the region (2) is a liquid, but in the present invention, is a liquefied gas obtained by compressing a substance existing as a gas at normal temperature (25°C) and normal pressure (l atm). Further, the substance present in the region (3) is a gas, but in the present invention, is a high-pressure gas whose pressure is 1/2 Pc or higher.
  • a substance usable as the compressive fluid is
  • Examples thereof include carbon monoxide, carbon dioxide, nitrogen monoxide, nitrogen, air, argon, helium, neon, krypton, methane, ethane, propane, 2, 3-dimethyl butane, ethylene, ammonia, n-butane, isobutane, n-pentane, isopentane, and chlorotrifluoromethane. These may be used alone or in combination.
  • a compressive fluid for melting the pressure plastic material (such compressive fluid may be referred to as a "first compressive fluid” hereinafter) is appropriately selected depending on the intended purpose without any limitation, but it is preferably carbon dioxide, as it can easily form a supercritical state, it is noninflammable and has high safety, and it
  • carbon dioxide has affinity to a carbonyl structure.
  • a second compressive fluid may be used.
  • the second compressive fluid is supplied to the melt when the melt is ejected as a jet.
  • the second compressive fluid is appropriately selected depending on the intended purpose without any limitation, and examples thereof include those materials listed as the
  • the second compressive fluid preferably used a nitrogen-containing compressive fluid that is a substance (e.g., oxygen and nitrogen) having the maximum inversion temperature of 800 K or lower.
  • a nitrogen-containing compressive fluid that is a substance (e.g., oxygen and nitrogen) having the maximum inversion temperature of 800 K or lower.
  • nitrogen-containing means to contain a nitrogen molecule, and therefore it can be said that the air is also “nitrogen-containing.”
  • the nitrogen has the maximum inversion temperature of 620 K, and has the low maximum inversion temperature compared to that of a substance, such as carbon dioxide (maximum inversion temperature- " 1,500 K). Therefore, reduction in temperature due to the
  • the maximum inversion temperature of the second compressive fluid is excessively high, such as in the case of the carbon dioxide, cooling due to the Joule-Thomson effect becomes excessive when the melt is jetted. Therefore, the melt is solidified before the melt is formed into particles. As a result, fibrous or cohesion products may be included in a final product.
  • the melt may be solidified inside a nozzle, which is used for jetting the melt, and therefore it may not be able to produce particles having small particle diameter with a narrow particle size distribution over a long period.
  • the compressive fluid can be used in combination with an entrainer (cosolvent).
  • the entrainer is appropriately selected depending on the intended purpose without any limitation, and examples thereof include- ' alcohol, such as methanol, ethanol, and propanoic ketone, such as acetone, and methyl ethyl ketone; and an organic solvent, such as toluene, ethyl acetate, and tetrahydrofuran.
  • ' alcohol such as methanol, ethanol, and propanoic ketone, such as acetone, and methyl ethyl ketone
  • an organic solvent such as toluene, ethyl acetate, and tetrahydrofuran.
  • particles produced by the method for producing particles of the present invention are a toner
  • another fluid may be used in combination with the
  • compressive fluid As for the another fluid, preferred are fluids that can easily control solubility of a toner composition. Specific examples thereof include methane, ethane, propane, butane, and ethylene.
  • the particle forming step is jetting the melt obtained by melting the pressure plastic material to form particles, and the particle forming step is carried out using the apparatus for producing particles, which will be described below.
  • FIGs. 4 to 6 are each a schematic diagram illustrating one example of an apparatus for producing particles.
  • the apparatus for producing particles 1 contains a bomb 11, pump 12a, valve 13a, high pressure cell 14, pump 12b, valve 13b, and nozzle 32, which are connected with super high pressure pipes (30a, 30b, 30c, 30d, 30e, 3 Of).
  • the bomb 11 is a pressure resistant container for storing and supplying a first compressive fluid.
  • the bomb 11 may store gas or a solid that will be a compressive fluid upon application of heat or pressure during the process that it is supplied to the high pressure cell 14, or within the high pressure cell 14. In this case, the gas or solid stored in the bomb 11 is turned into the state of (l), (2) or (3) of the phase diagram of FIG. 3 in the high pressure cell 14 by applying heat or pressure.
  • the pump 12a is a device for sending the compressive fluid stored in the bomb 11 to the high pressure cell 14.
  • the valve 13a is a device configured to open or close a path between the pump 12a and the high pressure cell 14 to adjust the flow rate of the compressive fluid, or to shut off the flow thereof.
  • the high pressure cell 14 is equipped with a
  • thermoregulator is a device configured to bring the
  • a back pressure valve 14a is provided to the high pressure cell 14, and the internal pressure of the high pressure cell 14 can be controlled by opening or closing the back pressure valve 14a.
  • a stirrer is provided to the high pressure cell 14, and the compressive fluid and the pressure plastic material can be mixed by stirring using the stirrer.
  • the pump 12b is a device for sending the melt in the high pressure cell 14 to the nozzle 32.
  • the valve 13b is a device configured to open or close the path between the pump 12b and the nozzle 32 to adjust the flow rate of the melt, which has been obtained by melting the pressure plastic material, or to shut off the flow thereof.
  • the nozzle 32 is provided at an edge of the super high pressure pipe 30f, and a device configured to jet the melt.
  • a type of the nozzle 32 is appropriately selected depending on the intended purpose without any limitation, but it is
  • a diameter of the nozzle 32 is not particularly limited, as long as the pressure can be maintained constant during jetting.
  • the diameter of the nozzle 32 is excessively large, the pressure at the time of jetting excessively decreases, and the viscosity of the melt is increased, possibly causing difficulty in producing particles. In some cases, it is necessary to provide a large supply pump for maintaining the pressure.
  • the diameter of the nozzle is excessively small, the nozzle 32 is easily clogged with the melt, possibly causing difficulty in obtaining desired particles.
  • the upper limit of the diameter of the nozzle is preferably 500 ⁇ or smaller, more preferably 300 ⁇ or smaller, and even more preferably 100 ⁇ or smaller.
  • the lower limit of the diameter of the nozzle is preferably 5 ⁇ or greater, more preferably 20 ⁇ or greater, and even more preferably 50 ⁇ or greater.
  • the melt in the high pressure cell 14 is not directly jetted.
  • the melt is passed through the super high pressure pipes (30d, 30e, 30f), followed by jetted from the nozzle 32.
  • the compressive fluid mixed at the high pressure cell 14 is sufficiently diffused in the pressure plastic material, and therefore the productivity improves.
  • FIG. 5 An apparatus for producing particles 2 will be explained next with reference to FIG. 5.
  • the units, systems, and devices identical to those of the apparatus for producing particles 1 of FIG. 4 are identified with the same reference numbers, and explanations thereof are emitted.
  • the apparatus for producing particles 3 contains a cell 24, a pump 12b, a valve 13b, a blending device 17, a valve 13c, and a nozzle 32, which are connected with super high pressure pipes (30d, 30e, 30j, 30k, 30f).
  • the valve 13a is connected to the blending device 17 with the super high pressure pipe 30c.
  • the super high pressure pipe 30c is equipped with a heater 16.
  • the bomb 11 is a pressure resistant container for storing and supplying a first compressive fluid.
  • the bomb 11 may store therein gas or a solid that will be turned into a compressive fluid by heating the heater 16, or applying pressure by the pump 12a.
  • the gas or solid stored in the bomb 11 is turned into a state of (1), (2), or (3) of the phase diagram of FIG. 3 in the blending device 17.
  • the cell 24 is equipped with a thermoregulator, and is a device configured to heat the pressure plastic material, which has been loaded in the cell 24 in advance.
  • the cell 24 is also equipped with a stirrer, and the pressure plastic material can be heated homogeneously by stirring using the stirrer.
  • the blending device 17 is a device configured to
  • the blending device 17 includes a conventional T-shape coupling, a swirl mixer which actively utilizes a swirl flow, and a central collision mixer in which two fluids are brought into collision in a mixing part.
  • the valve 13c is a device configured to open or close the path between the blending device 17 and the nozzle 32 to adjust the flow rate of the melt, or to shut off the flow thereof.
  • the apparatus for producing particles 2 particles can be produced without using the high pressure cell 14, and therefore the weight saving of the apparatus can be achieved.
  • the pressure plastic material supplied from the cell 24 and the first compressive fluid supplied from the bomb 11 are continuously brought into contact with each other in the blending device 17 to thereby melt pressure plastic material in advance.
  • the compressive fluid and the pressure plastic material can be continuously mixed at a constant rate, and therefore a uniform melt can be obtained.
  • the apparatus for producing particles 3 contains a bomb 21, a pump 22, and a valve 23, which are connected with super high pressure pipes (30g, 30h). Moreover, the apparatus for producing particles 3 contains a blending device 31, which is connected to a nozzle 32, connected to a valve 13c with a super high pressure pipe 30f, and connected to the valve 23 with a super high pressure pipe 30i.
  • the super high pressure pipe 30i is equipped with a heater 16.
  • the bomb 21 is a pressure resistant container for storing and supplying a second compressive fluid.
  • the bomb 21 may store gas or a solid, which will be turned into a compressive fluid by heating by a heater 26, or applying pressure by a pump 22.
  • the gas or solid stored in the bomb 21 is turned into the state of (l), (2), or (3) of the phase diagram of FIG. 3 in the blending device 31 by heating or applying pressure.
  • the pump 22 is a device configured to send the compressive fluid stored in the bomb 21 to the blending device 31.
  • the valve 23 is a device configured to open or close the path between the pump 22 and the blending device 31 to adjust the flow rate of the compressive fluid, or to shut off the flow thereof.
  • the blending device 31 is a device configured to
  • the blending device 31 include a conventional T-shape coupling, a swirl mixer which actively utilizes a swirl flow, and a central collision mixer in which two fluids are brought into collision in a mixing part.
  • the melt is jetted from the nozzle 32 while the second compressive fluid is supplied to the melt at the blending device 31.
  • the viscosity of the melt of the pressure plastic material can be reduced by the pressure of the second compressive fluid, and therefore the productivity improves.
  • a conventional coupling is used as the blending device (17, 31).
  • fluids each having different viscosity such as a resin melt and a compressive fluid
  • a static mixer such as the one disclosed JP-B No. 4113452
  • the static mixer has a mixing element (element) in a tubular housing.
  • This element does not have a moving part, but has a plurality of baffle plates arranged around a tube axis in the axial direction.
  • the element in the tube gives actions of dividing, turning over, and reversing to the fluid to mix, in the process that the fluid goes through the tubular housing.
  • a static mixer in which a large number of elements, each of which is formed of a honeycomb-shaped plate containing polygonal cells, are arranged together.
  • a fluid is mixed by receiving actions of dividing, turning over, and reversing, as the fluid sequentially moves through cells in a center part of the tube to cells in an outer part of the tube, and through the cells in the outer part of the tube to the cells in the center part of the tube.
  • the method for producing particles of the present invention contains: bringing a compressive fluid and a pressure plastic material into contact with each other to melt the pressure plastic material (melting step); and jetting a melt of the pressure plastic material, which is obtained by melting the pressure plastic material, and has a viscosity of 500 mPa s or lower, to form particles (particle forming step).
  • melted means a state of a raw material, such as a pressure plastic material, that it is plasticized or liquidized as well as swollen as a result of the contact with the compressive fluid.
  • the high pressure cell 14 is charged with raw materials, such as the pressure plastic material, and a colorant.
  • these materials may be mixed by a mixer or the like in advance, and then melt kneaded by a roll mill or the like before the high pressure cell 14 is charged with the raw materials.
  • the high pressure cell 14 is sealed, and the raw materials is stirred by a stirrer of the high pressure cell 14.
  • the pump 12a is operated to compress the first compressive fluid stored in the bomb 11, and the valve 13a is open to thereby supply the first compressive fluid into the high pressure cell 14.
  • a carbonic acid gas (carbon dioxide) bomb is used as the bomb 11.
  • the temperature inside the high pressure cell 14 is adjusted to the temperature at which the supplied carbon dioxide is turned into a compressive fluid, by a thermoregulator. Note that, the upper limit of the temperature inside the high pressure cell 14 is appropriately selected depending on the intended purpose without any
  • the thermal decomposition temperature means onset temperature for weight loss of a sample due to thermal decomposition thereof, as measured by a thermo gravimetry analyzer (TGA).
  • TGA thermo gravimetry analyzer
  • the pressure plastic material may be oxidized, or may be deteriorated due to scission of molecular chains thereof, which may lead to low durability of the pressure plastic material.
  • a resulting toner, as a final product may have undesirable color tone, transparency, fixing property, heat resistant storage stability, and charging property. Further, energy consumption of the heating process increases.
  • the pressure in the high pressure cell 14 can be adjusted to the predetermined pressure by adjusting the pump 12a, and the back pressure valve 14a.
  • the pressure applied to the raw materials, such as a pressure plastic material, in the high pressure cell 14 in the melting step of the method for producing particles of the present invention is appropriately selected depending on the intended purpose without any limitation, but it is preferably 1 MPa or greater, more preferably 10 MPa to 200 MPa, and even more preferably 31 MPa to 100 MPa.
  • the pressure inside the high pressure cell 14 is less than 1 MPa, it may not be able to attain a plasticizing effect enough to form the pressure plastic material into particles. It is no problem however high the pressure inside of the high pressure cell 14 is, but higher pressure thereof requires a durable device, which increase an equipment cost.
  • the pressure plastic material is melted by bringing the compressive fluid and the raw materials containing the pressure plastic material into contact with each other.
  • the melt obtained by melting the pressure plastic material is stirred by the stirrer until the viscosity of the melt becomes constant.
  • the viscosity of the melt is appropriately selected depending on the intended purpose without any limitation, provided that it is the viscosity which allows the melt to jet from the nozzle 32. The lower the viscosity is more preferable, because the melt can be jetted even with a nozzle having a small opening diameter, and fine particles can be easily formed.
  • the viscosity of the melt is 500 mPa s or lower, preferably 300 mPa s or lower, more preferably 100 mPa s or lower, and even more preferably 20 mPa-s or lower for obtaining a toner capable of achieving high image quality.
  • the viscosity of the melt is greater than 500 mPa s, it may be difficult to form particles, or coarse particles, fibrous products, foam, or cohesion of particles may be formed.
  • the pressure plastic material is used in the present invention, and therefore the viscosity of the pressure plastic material is reduced by the pressure of the compressive fluid. As a result, the pressure plastic material and the compressive fluid are homogeneously mixed to thereby yield the melt having a low viscosity.
  • a cell 24 is charged with raw materials, such as a pressure plastic material, and a colorant.
  • raw materials such as a pressure plastic material, and a colorant.
  • these substances may be mixed by a mixer, and melt kneaded by a roll mill in advance to add the raw materials to the cell 24.
  • the cell 24 is sealed, and the raw materials are stirred by a stirrer of the cell 24 and heated.
  • the temperature in the cell 24 is not particularly limited, as long as it is
  • the pump 12a is operated to compress the carbon dioxide serving as the first compressive fluid stored in the bomb 11, and the valve 13a is open, to thereby supply the first compressive fluid to the blending device 17.
  • a carbonic acid gas (carbon dioxide) bomb is used as the bomb 11.
  • the first compressive fluid to be supplied is heated by a heater 16 in the super high pressure pipe 30c.
  • the set temperature of the heater 16 is not particularly limited, as long as it is temperature at which the supplied carbon dioxide is turned into the compressive fluid.
  • the pump 12b is operated and the valve 13b is open.
  • the pressure plastic material supplied from the cell 24, and the first compressive fluid supplied from the bomb 11 are continuously brought into contact with each other and homogeneously mixed in the blending device 17, to thereby melt the pressure plastic material.
  • the viscosity of the melt obtained by melting the pressure plastic material is appropriately selected depending on the intended purpose without any limitation, but it is 500 mPa s or lower, preferably 300 mPa s or lower, more preferably 100 mPa s or lower, and even more preferably 20 mPa s or lower for obtaining a toner capable of achieving high image quality.
  • the pressure plastic material is plasticized in advance in the cell 24, and the pressure plastic material and the compressive fluid are brought into contact with each other and mixed after reducing a difference in the viscosity between the pressure plastic material and the compressive fluid. Therefore, a uniform melt can be attained.
  • the pressure plastic material is plasticized in advance in the cell 24 by applying heat, but the pressure plastic material may be plasticized in advance by applying pressure, or applying heat and pressure.
  • the RESS process is a rapid expansion method, in which a material, which will be a solute, is saturated and dissolved in a supercritical fluid under high pressure, and particles are precipitated using rapid reduction in solubility due to rapid reduction in pressure as a melt is jetted from a nozzle.
  • the pressure of the supercritical fluid is immideately reduced down to the atmospheric pressure at the outlet of the nozzle, and the saturated solubility of the solude decreases along with the reducdion in the pressure. Specifically, a large supersaturation is achieved within an extremely short period, and therefore large number of fine aggregation cores are generated, to thereby precipitate without hardly any growth. As a result, particles of sub-micron order can be obtained.
  • a supercritical fluid is saturated and dissolved in a melt of a pressure plastic material (in the present invention, operated at saturated dissolution concentration or lower), and the resulting liquid is sparyed through a nozzle to thereby rapidly reduce the pressure of the liquid.
  • the solubility of the supercritical fluid dissolved in the melt is rapidly reduced along with the aforementioned reduction in the pressure.
  • the supercritical fluid is turned into foams to separate the melt, and particles are formed from the melt due to a cooling effect originated from adiabatic expansion.
  • the mixture obtained by bringing the compressive fluid and the pressure plastic material into contact each other in the high pressure cell 14 or the blending device 17 is jetted from a nozzle 32 by opening the valve 13c.
  • the back pressure valve 14a, pumps (12a, 12b), thermoregulator, and the like are controlled to maintain constant temperature and pressure of the high pressure cell 14 or cell 24.
  • the pressure inside the high pressure cell 14 or blending device 17 is not particularly limited.
  • the melt jetted from the nozzle 32 is formed into particles, followed by solidified.
  • the pressure plastic material and the compressive fluid are
  • the pump 22 is operated and the valve 23 is open so that a second compressive fluid stored in the bomb 21 is supplied to the blending device 31.
  • a nitrogen bomb is used as the bomb 21.
  • the pressure of the supplied second compressive fluid is appropriately selected depending on the intended purpose without any limitation, but it is preferably 1 MPa or greater, more preferably 10 MPa to 200 MPa, and even more preferably 31 MPa to 100 MPa.
  • the second compressive fluid to be supplied is heated by a heater 26 in the super high pressure pipe 30i.
  • temperature of the heater 26 is not particularly limited as long as it is temperature at which the supplied nitrogen is turned into a compressive fluid.
  • the pumps (12a, 12b) are operated to supply the melt of the pressure plastic material from the blending device 17 to the blending device 31.
  • the pumps (12a, 12b), thermoregulator and the like are controlled to maintain constant temperature and pressure inside the cell 24.
  • the pressure inside the cell 24 is not particularly limited, but it can be set equal to the pressure of the compressive fluid supplied from a second path.
  • the melt supplied from the blending device 17 and the second compressive fluid supplied from the bomb 21 are homogeneously mixed in the blending device 31. As a result, the melt is jetted from the nozzle 32 under the atmospheric pressure utilizing the pressure difference, while supplying the second compressive fluid to the melt.
  • the solid content of the melt jetted is reduced by the supplied second compressive fluid, and therefore the viscosity of the melt is further reduced.
  • the jet speed outlet linear speed
  • shearing force to the melt increases due to the increase in the outlet linear speed, as well as controlling the temperature of the jetted melt constant.
  • nitrogen is used as the second compressive fluid, moreover, a decrease in temperature due to the Joule-Thomson effect, which is caused along the change in the pressure adjacent to the nozzle 32, is inhibited, which prevents clogging of the nozzle 32.
  • the melt jetted from the nozzle 32 is formed into particles, followed by solidified.
  • the melt obtained by continuously bringing the pressure plastic material and the compressive fluid into contact in the blending device 17 is supplied to the nozzle 32, and therefore particles can be continuously formed.
  • the particles to be produced are appropriately selected depending on the intended purpose without any limitation.
  • the particles include particles of daily use products, medical products, and cosmetic products.
  • the shape, size, and material of the particles produced by the method of the present invention are appropriately selected depending on the intended final product without any limitation.
  • the method for producing particles of the present invention can produce particle without using an organic solvent, as a compressive fluid is used. Therefore, particles, which do not substantially contain an organic solvent, can be obtained. Note that, the particles, which do not substantially contain an organic solvent, mean that an amount of the organic solvent in the particles as measured by the following method is equal to or less than the detection limit.
  • the amount of the residual solvent of the particles is measured in the following measurement method. To 1 part by mass of particles to be measured, 2 parts by mass of 2-propanol is added, and dispersed by ultrasonic wave for 30 minutes, and then the mixture is stored in a refrigerator at 5°C for 1 day or longer, to thereby extract a solvent in the particles. A supernatant liquid is analyzed by gas chromatography (GC- 14A,
  • the measurement conditions for such analysis are as follows.
  • Carrier gas He 2.5 kg/cm 2
  • the particles of the present embodiment may contain pores therein as a result of the transformation of the compressive fluid to gas in the particle forming step.
  • the average maximum Feret diameter of the pores is 10 nm or greater but smaller than 500 nm, more preferably 10 nm or greater but smaller than 300 nm.
  • the maximum Feret diameter is a diameter with which a distance between horizontal lines becomes the greatest, when a target is held between the two horizontal lines.
  • the average maximum Feret diameter of the pores can be determined in the following manner. A cross-section of particles is observed under an electron microscope or the like, and a cross-sectional photograph is taken. The cross-sectional photograph is processed using an image processing software to binarize the information, and pores are identified. 30 pores, which have been identified, are selected from those having the largest maximum Feret diameter of the pores in order, and the average thereof is determined as the average of the maximum Feret diameter.
  • the particles are used as a toner, for example, as the particles have pores therein, the electric power consumption for fixing the toner to a recording medium can be reduced.
  • an external additive such as hydrophobic silica, added to the toner is not easily embedded into toner particles, and therefore shelf life of the toner is improved.
  • a toner produced by the method for producing particles of the present invention is not particularly limited in terms of the properties thereof, such as a shape, and a size.
  • the toner preferably have image density, average circularity, mass average particle diameter and a ratio (mass average particle diameter/number average particle diameter) of the mass average particle diameter to the number average particle diameter as described below.
  • the image density of the toner is appropriately selected depending on the intended purpose without any limitation, but the gray level thereof as measured by a spectrometer (938 spectrodensitometer, manufactured by X-Rite) is preferably 1.90 or greater, more preferably 2.00 or greater, and even more preferably 2.10 or greater. When the image density is less than 1.90, the image density of an image is low, and therefore a high quality image may not be obtained.
  • a spectrometer 938 spectrodensitometer, manufactured by X-Rite
  • the image density can be measured, for example, in the following manner.
  • imagio Neo 450 manufactured by Ricoh Company Limited
  • a solid image is formed on a photocopy sheet (TYPE6000 ⁇ 70W>, manufactured by Ricoh Company Limited) to give a developer deposition amount of 1.00 ⁇ 0.05 mg/cm 2 with a fixing roller having surface
  • the image density of the obtained solid image is measured at randomly selected 6 points by means of the aforementioned spectrometer. The average value is calculated from the measured values, and determined as the image density.
  • the average circularity of the toner is appropriately selected depending on the intended purpose without any
  • the average circularity of the toner is preferably 0.900 to 0.980, more preferably 0.950 to 0.975.
  • a proportion of the particles having the average circularity of less than 0.94 is preferably 15% by mass or less.
  • image smear for example, in a case of formation of an image having a high-image area ratio such as photographic image, a toner forming an untransferred image due to a paper-feeding defect or the like accumulates on the photoconductor remains an untransferred toner thereon, and the untransferred toner may cause background smear on images, or a charging roller etc. that contact-charges the photoconductor is contaminated with the untransferred toner, thereby the toner may not exert its intrinsic charging ability.
  • the average circularity can be measured by means of a flow particle image analyzer, for example, a flow particle image analyzer FPIA-2000, manufactured by Sysmex Corporation.
  • a flow particle image analyzer for example, a flow particle image analyzer FPIA-2000, manufactured by Sysmex Corporation.
  • fine dust is removed from water using a filter, such that the number of particles inside a measured area (for example, 0.60 ⁇ or larger but smaller than 159.21 ⁇ in circle equivalent diameter) in 10 ⁇ 3 cm 3 of the water is 20 or fewer, then a few drops of a nonionic surfactant (preferably, CONTAMINON N, manufactured by Wako Pure Chemical Industries, Ltd.) are added into 10 mL of the water.
  • a nonionic surfactant preferably, CONTAMINON N, manufactured by Wako Pure Chemical Industries, Ltd.
  • the sample dispersion liquid is passed through a flow path (which widens with respect to the flow direction) of a flat, transparent flow cell (approximately 200 ⁇ in thickness) .
  • a strobe and a CCD camera are provided so as to be positioned oppositely to each other with respect to the flow cell.
  • a strobe light is emitted at intervals of 1/30 seconds to obtain images of particles flowing in the flow cell; as a result, the particles are photographed as two-dimensional images having certain areas which are parallel to the flow cell. Based upon the areas of the two-dimensional images of the particles, the diameters of circles having the same areas are calculated as circle equivalent diameters.
  • the circle equivalent diameters of 1,200 or more particles can be measured in approximately 1 minute, and the number of particles based upon the distribution of the circle equivalent diameters, and the proportion (number %) of particles having a prescribed circle equivalent diameter can be measured.
  • the results (frequent % and cumulative %) can be obtained dividing the range of 0.06 ⁇ to 400 ⁇ into 226 channels (one octave is divided into 30 channels).
  • the practical measurement of particles is carried out concerning particles which are 0.60 ⁇ or lager but smaller than 159.21 ⁇ in circle equivalent diameter.
  • the mass average particle diameter of the toner is appropriately selected depending on the intended purpose without any limitation, but it is preferably 3 ⁇ to 10 ⁇ , more preferably 3 ⁇ to 8 ⁇ . When the mass average particle diameter thereof is smaller than 3 ⁇ , the toner of a
  • the two-component developer may be fused onto a surface of a carrier particle after being stirred over a long period in a developing device, lowering the charging ability of the carrier.
  • the toner may cause filming to a developing roller, or may be fused onto a member for thinning a toner layer, such as a blade.
  • the mass average particle diameter is greater than 10 ⁇ , it is difficult to produce an image having high resolution and high quality, and a variation in the particle size of the toner may be large when the toner is supplied to the developer to compensate the consumed toner.
  • a ratio (mass average particle diameter/number average particle diameter) of the mass average particle diameter to the number average particle diameter is appropriately selected depending on the intended purpose without any limitation, but it is preferably 1.00 to 1.25, more preferably 1.00 to 1.10.
  • the ratio (mass average particle diameter/number average particle diameter) of the mass average particle diameter to the number average particle diameter is greater than 1.25, in case of a two-component developer, a toner is fused onto a surface of carrier due to stirring performed over a period in a developing device, which may reduce charging ability of the carrier.
  • the toner may cause filming to a developing roller, or may be fused onto a member for thinning a toner layer, such as a blade. Moreover, it is difficult to produce an image having high resolution and high quality, and a variation in the particle size of the toner may be large when the toner is supplied to the developer to compensate the consumed toner.
  • the mass average particle diameter, and the ratio (mass average particle diameter/number average particle diameter) of the mass average particle diameter to the number average particle diameter can be measured, for example, by means of a particle size analyzer, Coulter Counter TAII, manufactured by Bechman Electronics, Inc.
  • the developer of the present invention is appropriately selected depending on the intended purpose without any
  • the developer includes a one-component developer containing the toner produced by the aforementioned method, and a two-component developer containing the toner produced by the aforementioned method and a magnetic carrier.
  • the toner include a color toner (e.g., yellow, cyan, magenta, and black), and a clear toner.
  • the magnetic carrier is appropriately selected depending on the intended purpose without any limitation, provided that it contains a magnetic material.
  • Specific examples of the magnetic carrier include hematite, iron powder, magnetite, and ferrite.
  • An amount of the magnetic carrier is preferably 5 parts by mass to 50 parts by mass, more preferably 10 parts by mass to 30 parts by mass, relative to 100 parts by mass of the toner.
  • the image forming apparatus of the present invention contains ⁇ a latent electrostatic image bearing member? ' a latent electrostatic image forming unit configured to form a latent electrostatic image on the latent electrostatic image bearing member; a developing unit configured to develop the formed latent electrostatic image with the toner of the present invention to form a visible image; a transfer unit configured to transfer the developed visible image to a recording medium; and a fixing unit configured to fix the transferred visible image onto the recording medium.
  • the image forming apparatus of the present invention may further contain other units, if necessary.
  • FIG. 7 is a schematic diagram illustrating one example of the image forming apparatus of the present invention.
  • the image forming apparatus 200 develops a latent electrostatic image with the toner produced by the method for producing particles described above to form a visible image, transfers the visible image to a sheet, which is one example of a recording medium, and fix the visible image on the sheet to form an image.
  • the image forming apparatus 200 is an electrophotographic printer is explained, but the image forming apparatus is not limited to the electrophotographic printer, and may be a photocopier, or a facsimile.
  • the image forming apparatus 200 is equipped with a paper feeding element 210, a transporting element 220, an image forming element 230, a transferring element 240, and a fixing element 250.
  • the paper feeding element 210 is equipped with a paper feeding cassette 211 in which sheets to be fed is stored, and a feeding roller 212 configured to feed sheets stored in the paper feeding cassette 211 one by one.
  • the transporting element 220 is equipped with a roller 221 configured to transport the sheet fed by the feeding roller 212 to the side of the transferring element 240, a pair of timing rollers 222 configured to send the sheet transported by the roller 221 to the transferring element 240 with the predetermined timing, and a paper ejecting roller 223 configured to eject the sheet on which the toner has been fixed by the fixing element 250 to a paper ejection tray 224.
  • the image forming element 230 is equipped with an image forming unit Y, which is configured to form an image using a developer containing a yellow toner (toner Y), an image forming unit C, which is configured to form an image using a developer containing a cyan toner (toner C), an image forming unit M, which is configured to form an image using a developer
  • magenta toner toner M
  • image forming unit K which is configured to form an image using a developer
  • the toners (Y, C, M, K) are each the toner produced by the aforementioned method for producing particles.
  • each image forming unit has substantially the same mechanical structures, provided that a developer for use is different.
  • Each image forming unit contains- ' a
  • a charger 232Y, 232C, 232M, 232K
  • a toner cartridge 237Y, 237C, 237M, 237K
  • a developing device 234Y, 234C, 234M, 234K
  • a diselectrification device 235Y, 235
  • the exposure device 233 is a device, in which laser light L emitted from a light source 233a based on the image information is reflected with a polygon mirror (233bY, 233bC, 233bM, 233bK), which is rotatably driven by a motor, to radiate the
  • a latent electrostatic image based on the image information is formed on the photoconductor drum 231 by means of the exposure device 233.
  • the transferring element 240 contains ⁇ a driving roller 241 and a driven roller 242; an intermediate transfer belt 243, which is supported by these rollers, and is serving as a transfer member capable of rotating anticlockwise in FIG. 7 along with the rotation of the driving roller 241; a primary transfer roller (244Y, 244C, 244M, 244K) provided to face the photoconductor drum 231 via the intermediate transfer belt 243; and a secondary transfer roller 246 provided to face a secondary counter roller 245 via the intermediate transfer belt 243 at the transfer position of the toner image to a sheet.
  • primary transfer bias is applied to the primary transfer roller 244 to transfer (primary transfer) each toner image formed on the surface of the
  • secondary transfer bias is applied to the secondary transfer roller 246 to transfer (secondary transfer) the toner image on the intermediate transfer belt 243 to a transported sheet transported, which is nipped between the secondary transfer roller 246 the secondary counter roller 245.
  • the fixing element 250 contains- a heat roller 251 which contains a heater therein, and is configured to heat a sheet to temperature higher than the minimum fixing temperature of the toner; and a pressure roller 252, which is rotatably pressed against the heat roller 251 to form a contact surface (nip).
  • the minimum fixing temperature is the lower limit of the temperature at which the toner can be fixed.
  • the image forming apparatus of the present invention uses a toner produced by the method of present invention, which has a sharp particle size distribution and excellent toner properties (e.g., charging property, environmental property, and storage stability), and therefore the image forming apparatus can form a high quality image.
  • toner produced by the method of present invention, which has a sharp particle size distribution and excellent toner properties (e.g., charging property, environmental property, and storage stability), and therefore the image forming apparatus can form a high quality image.
  • the melt containing the pressure plastic material and the compressive fluid is jetted into the air
  • the embodiment of the present invention is not limited thereto.
  • the melt can be jetted into the atmosphere that has higher pressure than the atmospheric pressure, but has lower pressure than the pressure inside the nozzle 32.
  • control of particle diameters or particle size distribution can be enhanced by controlling the jet speed (outlet linear velocity).
  • a cooling effect to the melt jetted from the nozzle 32 due to the Joule-Thomson effect can be suppressed, and therefore heating by the heater 26 can be avoided, which leads to energy saving and cost saving.
  • a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen inlet tube was charged with 229 parts by mass of a bisphenol A ethylene oxide (2 mol) adduct, 529 parts by mass of a bisphenol A propylene oxide (3 mol) adduct, 208 parts by mass, of terephthalic acid 46 parts by mass of adipic acid, and 2 parts by mass of dibutyl tin oxide, and the mixture was allowed to react for 8 hours at 230°C under the atmospheric pressure. The resultant was allowed to react for 5 hours under the reduced pressure of 10 mmHg to 15 mmHg. Thereafter, 44 parts by mass of trimellitic anhydride was added to the reaction vessel, and the resulting mixture was allowed to react for 2 hours at 180°C under the atmospheric pressure to thereby yield Polyester Resin 1.
  • Polyester Resin 1 had the number average molecular weight of 2,500, weight average molecular weight of 6,700, glass transition temperature Tg of 43°C, and acid value of 25 mgKOH/g. Moreover, the gradient of the change in the glass transition temperature of Polyester Resin 1 relative to pressure was -10 °C/MPa.
  • the gradient of the glass transition temperature of Polylactic Acid Resin relative to the pressure as measured in the aforementioned method was -20 0 C/MPa.
  • a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen inlet tube was charged with 343 parts by mass of a bisphenol A ethylene oxide (2 mol) adduct, 166 parts by mass of isophthalic acid, and 2 parts by mass of dibutyl tin oxide, and the mixture was allowed to react for 8 hours at 230°C under the atmospheric pressure.
  • the resultant was further allowed to react for 5 hours under the reduced pressure of 10 mmHg to 15 mmHg, and was cooled to 110°C.
  • 17 parts of isophorone diisocyanate in toluene was added, and the mixture was allowed to react for 5 hours at 110°C, followed by removing the solvent, to thereby obtain Urethane-Modified Polyester Resin 2- 1.
  • Urethane-Modified Polyester Resin 2- 1 had the weight average molecular weight of 72,000, and isocyanate content of 0.7% by mass.
  • Polyester Resin 2-2 which had not been modified. Polyester Resin 2-2 had the number average molecular weight of 2,400, hydroxy value of 51 mgKOH/g, and acid value of 5 mgKOH/g.
  • the gradient of the change in the glass transition temperature of Polyester 2 relative to the pressure was measured in the aforementioned method, and was -3 °C/MPa.
  • Polyester Resin 3 had the melting point of 119°C, number average molecular weight Mn of 710, weight average molecular weight Mw of 2, 100, acid value of 24 mgKOH/g, and hydroxyl value of 28 mgKOH/g.
  • a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen inlet tube was charged with 283 parts by mass of sebacic acid, 215 parts by mass of 1,6-hexanediol, and 1 part by mass of titanium dihydroxybis(triethanol aminate) as a
  • condensation catalyst and the resulting mixture was allowed to react for 8 hours under a flow of nitrogen gas at 180°C, while removing water as generated.
  • the resultant was gradually heated to 220°C, and was allowed to react for 4 hours under a flow of nitrogen gas, while removing the generated water and
  • a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen inlet tube was charged with 283 parts by mass of sebacic acid, 215 parts by mass of 1,6-hexanediol, and 1 part by mass of titanium dihydroxybis(triethanol aminate) as a
  • condensation catalyst and the resulting mixture was allowed to react for 8 hours under a flow of nitrogen gas at 180°C, while removing water as generated.
  • the resultant was gradually heated to 220°C, and was allowed to react for 4 hours under a flow of nitrogen gas, while removing the generated water and
  • Polyurethane Resin 1 (crystalline polyurethane resin) having Mw of 20,000, and a melting point of 65°C.
  • the gradient of the change in the glass transition temperature of Polyurethane Resin 1 relative to the pressure was measured in the aforementioned method, and was -15 °C/MPa.
  • the gradient of the change in the glass transition temperature of Polyphenylene Sulfide Resin relative to the pressure was measured in the aforementioned method, and was -1 °C/MPa.
  • Example 1 a toner was produced using the apparatus for producing particles 2 illustrated in FIG. 5.
  • a carbonic acid gas (carbon dioxide) bomb was used as the bomb 11.
  • a cell 24 of the apparatus for producing particles 2 depicted in FIG. 5 was charged with Polyester Resin 1, and Polyester Resin 1 was heated to 160°C and plasticized.
  • the pump 12a was operated and the valve 13a was open so that the carbon dioxide was supplied as a first compressive fluid at 160°C, and 2 MPa.
  • the pump 12b was operated and the valve 13b was open so that the kneaded product of plasticized Polyester Resin 1 and the first compressive fluid were mixed in the blending device 17.
  • the melt obtained in blending device 17 had the viscosity of 450 mPa s. Note that, the viscosity of the melt was measured in the manner described below.
  • the value 13c was open in the aforementioned state, and the pump 12a and the pump 12b were operated to jet the melt from a nozzle 32 having an opening diameter of 100 ⁇ .
  • the jetted melt formed particles, and the particles were solidified to thereby obtain Resin Particles 1.
  • Resin Particles 1 had the volume average particle diameter (Dv) of 72.6 ⁇ , number average particle diameter (Dn) of 9.3 ⁇ , and ratio Dv/Dn of 7.81. Note that, Dv, Dn, and Dv/Dn were measured in the manner described below.
  • Hydramotion Ltd. was used for the measurement of the viscosity of the melt.
  • a sampleand a compressive fluid carbon dioxide
  • the viscosity was measured under the conditions of 160°C, and 2 MPa.
  • volume average particle diameter, and ratio (volume average particle diameter/number average particle diameter) of the volume average particle diameter to the number average particle diameter were measured by means of a particle size analyzer, Coulter Counter TAII, manufactured by Bechman Electronics, Inc.
  • Resin Particles 2 to 4 were each produced in the same manner as in Example 1, provided that the processing
  • Resin Particles 2 to 4 were each subjected to the
  • Polyester Resin 1 of Synthesis Example 1 95 parts by mass ⁇ Colorant (copper phthalocyanine blue, C.I. Pigment Blue 15 ⁇ 3, manufactured by Dainichiseika Color & Chemicals Mfg. Co. Ltd.)
  • Toner 5 was obtained in the same manner as in Example 1, provided that the processing temperature, processing pressure and nozzle diameter were changed as depicted in Table 1.
  • Toner 5 was subjected to the measurements of the viscosity of the melt, volume average particle diameter (Dv), number average particle diameter (Dn), and ratio Dv/Dn in the same manner as in Example 1. The results are presented in Table 1.
  • Example 6 a toner was produced in the following manner using the apparatus for producing particles 3 depicted in FIG. 6.
  • a carbonic acid gas (carbon dioxide) bomb was used as a bomb 11.
  • a nitrogen bomb was used as the bomb 21.
  • the mixture was melt-kneaded by a two-roll mill.
  • the kneaded product was rolled and cooled.
  • the resulting kneaded product was set in a cell 24 of the apparatus for producing particles 3 depicted in FIG. 6, and then heated to 130°C to plasticize.
  • the pump 12a was operated, and the valve 13a was open so that the carbon dioxide was supplied as a first compressive fluid at 130°C, and 65 MPa.
  • the pump 12b was operated and the valve 13b was open so that the plasticized kneaded product and the first compressive fluid were mixed in the blending device 17.
  • valve 23 was open, and supercritical nitrogen was sprayed from the nozzle 32 at using the pump 22 and the heater 26 so that the pressure and temperature were maintained at 65 MPa, and 135°C, respectively.
  • the valve 13c was open so that the melt obtained by bringing the kneaded product and the first compressive fluid into contact with each other is jetted from the nozzle 32, while supplying the second compressive fluid to the melt.
  • the temperature and pressure of the melt passing through the blending device 17 were constantly maintained at 130°C and 65 MPa respectively, by adjusting the pump 12a, the pump 12b, and the back pressure valve 14a. The jetted melt formed particles, followed by solidified to thereby obtain Toner 6.
  • Toner 6 was subjected to the measurements of the viscosity of the melt, volume average particle diameter (Dv), number average particle diameter (Dn), and ratio Dv/Dn in the same manner as in Example 1. The results are presented in Table 1.
  • Toner 7 was obtained in the same manner as in Example 5, provided that Polyester Resin 1 in the raw materials of the toner was replaced with Polylactic Acid Resin, and the processing temperature, processing pressure and nozzle diameter were changed as depicted in Table 1.
  • Toner 7 was subjected to the measurements of the viscosity of the melt, volume average particle diameter (Dv), number average particle diameter (Dn), and ratio Dv/Dn in the same manner as in Example 1. The results are presented in Table 1.
  • Resin Particles 8 were obtained in the same manner as in
  • Example 1 provided that Polyester Resin 1 was replaced with Polyester Resin 3, and the processing temperature, processing pressure and nozzle diameter were changed as depicted in Table 1.
  • Resin Particles 8 was subjected to the measurements of the viscosity of the melt, volume average particle diameter (Dv), number average particle diameter (Dn), and ratio Dv/Dn in the same manner as in Example 1. The results are presented in Table 1.
  • Toner 9 was obtained in the same manner as in Example 5, provided that Polyester Resin 1 was replaced with Polyester Resin 4, and the processing temperature and processing pressure were changed as depicted in Table 1.
  • Toner 9 was subjected to the measurements of the viscosity of the melt, volume average particle diameter (Dv), number average particle diameter (Dn), and ratio Dv/Dn in the same manner as in Example 1. The results are presented in Table 1.
  • Toner 10 was obtained in the same manner as in Example 5, provided that Polyester Resin 1 was replaced with
  • Toner 10 was subjected to the measurements of the viscosity of the melt, volume average particle diameter (Dv), number average particle diameter (Dn), and ratio Dv/Dn in the same manner as in Example 1. The results are presented in Table 1.
  • Toner 9 and Toner 10 were each subjected to a
  • cross-sectional photograph was processed using an image processing software to binarize the information, and pores were identified. 30 pores, which had been identified, are selected from those having the largest maximum Feret diameter of the pores in order, and the average thereof was determined as the average of the maximum Feret diameter. The results are presented in Table 1.
  • Polyester Resin 2 50 parts by mass
  • a 500 mL resin dissolver which was equipped with a stirrer, and a temperature sensor, and was capable of setting its internal pressure up to 30 MPa, and setting its internal
  • Example 2 The same process to that of Example 1 was carried out, provided that Polyester Resin 1 was changed to Polyphenylene Sulfide Resin 1, and the processing temperature, processing pressure and nozzle diameter were changed to the values as depicted in Table 1. However, particles could not be formed because the plasticization of the resin melt was insufficient. Table 1 1
  • Particles (or Toners) of Examples 1 to 10 were subjected to a measurement of a residual organic solvent amount in the following manner. The results thereof were all equal to or below the detection limit.
  • the amount of the residual solvent of the particles was measured in the following measurement method. To 1 part by mass of particles to be measured, 2 parts by mass of 2-propanol was added, and dispersed by ultrasonic wave for 30 minutes, and then the mixture was stored in a refrigerator at 5°C for 1 day or longer, to thereby extract a solvent in the particles.
  • GC- 14A gas chromatography
  • the concentration of the solvent was measured.
  • the measurement conditions for such analysis were as follows.
  • Carrier gas He 2.5 kg/cm 2
  • hydrophobic titanium oxide were added, and the mixture was mixed for 5 minutes by means of HENSCHEL MIXER at a rim speed of 8 m/s.
  • the resultant was passed through a mesh having an opening size of 100 ⁇ , to remove coarse particles.
  • the toners used for Developers 5 to 7 and 9 to 10 are respectively Toners 5 to 7 and 9 to 10.
  • Toners 5 to 7 and 9 to 10 To 100 parts by mass of each of Toners 5 to 7 and 9 to 10, 0.7 parts by mass of hydrophobic silica, and 0.3 parts of hydrophobic titanium oxide were added, and the mixture was mixed for 5 minutes by means of HENSCHEL MIXER at a rim speed of 8 m/s, to thereby prepare a one-component developer, Developers 15 to 17 and 19 to 20, respectively.
  • the toners used for Developers 15 to 17 and 19 to 20 are respectively Toners 5 to 7 and 9 to 10.
  • a solid image was output on plain paper, that was a transfer sheet ((Type 6200, manufactured by Ricoh Company Limited), with the low toner deposition amount of 0.3 mg/cm 2 ⁇ 0.1 mg/cm 2 . Then, the image density of the image was measured by a densitometer X-Rite (manufactured by X-Rite) . The results were evaluated based on the following criteria. [Evaluation Criteria]
  • Image density was 1.4 or more.
  • ⁇ ' Image density was 1.35 or more but less than 1.4.
  • C- Image density was 1.3 or more but less than 1.35.
  • a letter image pattern having an image area of 12% was continuously output on 100,000 sheet using each of the
  • the variation in the charge amount during the output test was evaluated. A small amount of the developer was collected from the sleeve, and the variation of the charge amount was determined by a blowoff method. The results are evaluated based on the following criteria.
  • the density of the white paper on which the residual toner had been transferred was measured by means of Macbeth reflection densitometer RD514. The results were evaluated based on the following criteria.
  • the total evaluation was performed based on the total points.
  • A The total points were 4 points to 5 points.
  • a method for producing particles containing:
  • melt has a viscosity of 500 mPa- s or lower at temperature and pressure as the melt is jetted.
  • ⁇ 2> The method according to ⁇ 1>, wherein the pressure plastic material is a resin having a carbonyl structure.
  • ⁇ 3> The method according to ⁇ 1> or ⁇ 2>, wherein the melt has a viscosity of 20 mPa s or less at the temperature and the pressure as the melt is jetted.
  • ⁇ 4> The method according to any one of ⁇ 1> to ⁇ 3>, wherein a gradient of a change in glass transition temperature of the pressure plastic material relative to pressure applied to the pressure plastic material is -5 °C/MPa or less.
  • ⁇ 5> The method according to ⁇ 4>, wherein the gradient of a change in glass transition temperature of the pressure plastic material relative to pressure applied to the pressure plastic material is -10 °C/MPa or less.
  • ⁇ 6> The method according to any one of ⁇ 1> to ⁇ 5>, wherein the jetting is performed while supplying the compressive fluid to the melt.
  • ⁇ 7> The method according to any one of ⁇ 1> to ⁇ 6>, wherein the bringing is continuously bringing the compressive fluid and the pressure plastic material into contact with each other, and the jetting is continuously jetting the melt to continuously form particles.
  • ⁇ 8> The method according to ⁇ 7>, wherein the bringing is continuously bringing the compressive fluid and the pressure plastic material into contact with each other without using a static mixer.
  • ⁇ 9> The method according to any one of ⁇ 1> to ⁇ 8>, wherein the pressure plastic material is a polyester resin.
  • ⁇ 11> The method according to any one of ⁇ 1> to ⁇ 10>, wherein the bringing is bringing the compressive fluid and the pressure plastic material, which is plasticized by heating, into contact with each other.
  • ⁇ 12> Particles, containing substantially no organic solvent, wherein the particles are particles produced by the method for producing particles according to any one of ⁇ 1> to ⁇ 11>.
  • a toner containing substantially no organic solvent, wherein the toner is particles produced by the method for producing particles according to any one of ⁇ 1> to ⁇ 11>, and wherein the pressure plastic material is a raw material of the toner.
  • a developer containing:
  • a latent electrostatic image forming unit configured to form a latent electrostatic image on the latent electrostatic image bearing member
  • a developing unit configured to develop the formed latent electrostatic image with the toner according to ⁇ 13> to form a visible image
  • a transferring unit configured to transfer the developed visible image to a recording medium
  • a fixing unit configured to fix the transferred image on the recording medium.
  • the particles have pores therein where the pores have an average maximum Feret diameter of 10 nm or greater but smaller than 500 nm.
  • photoconductor drum one example of the latent electrostatic image bearing member

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Abstract

La présente invention concerne un procédé de fabrication de particules qui consiste à mettre en contact un fluide de compression et un matériau plastique sous pression de façon à faire fondre le matériau plastique sous pression ; et à projeter un produit de fusion du matériau plastique sous pression afin de former des particules, le produit de fusion ayant une viscosité de 500 mPa•s ou inférieure à température et sous pression lorsque le produit de fusion est projeté.
PCT/JP2013/057111 2012-03-13 2013-03-07 Procédé de fabrication de particules, particules, encre en poudre, révélateur, et imageur WO2013137365A1 (fr)

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Cited By (1)

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Publication number Priority date Publication date Assignee Title
US11667055B2 (en) 2018-02-14 2023-06-06 Ricoh Company, Ltd. Method and apparatus for producing particles, particles, composition, particles dispersion liquid, and method for producing the particles dispersion liquid

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WO2019159988A1 (fr) 2018-02-14 2019-08-22 Ricoh Company, Ltd. Procédé et appareil de production de particules, particules, composition, liquide de dispersion de particules, et procédé de production du liquide de dispersion de particules

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