JP2006077166A - Method for producing resin microparticle and resin microparticle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the formation of hollow particles or irregular-shape particles and to provide resin microparticles having a uniform shape and a narrow width of particle size distribution by an environmentally friendly method. <P>SOLUTION: A method for producing the resin microparticles comprises discharging a dispersion in which a dispersoid mainly composed of a resin material is finely dispersed in an aqueous dispersion medium into a droplet form. The method comprises a step of removing the aqueous dispersion medium from the dispersion in the droplet form by heating, aggregating a plurality of dispersoids contained in the dispersion in the droplet form and providing an aggregate. The temperature of heating is 50-100°C and the resin having the glass transition point not lower than the temperature of heating is used as the resin material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing resin fine particles and resin fine particles.

As fine particles mainly composed of a resin material, that is, resin fine particles, for example, there are toners used in image forming apparatuses such as printers, copiers, and facsimiles that employ an electrophotographic system.
As a method for producing a toner, a method is known in which toner particles are obtained by solidifying droplets of a dispersion liquid in which a dispersoid containing a resin constituting the toner is finely dispersed in a dispersion medium (for example, Patent Documents). 1).

However, in the method of Patent Document 1, when the dispersion medium is removed from the dispersion liquid, the dispersion medium is heated at a relatively high temperature. Therefore, the speed at which the dispersion medium is removed is higher than the speed at which the fine particles derived from the dispersoids aggregate. In some cases, hollow portions are formed in the obtained toner particles. In particular, when the droplet is heated at a temperature higher than the glass transition point of the resin constituting the dispersoid, the fine particles are unintentionally joined before the fine particles derived from the dispersoid aggregate, In some cases, the formation of the hollow portion was further accelerated. In addition, the obtained aggregate has an irregular shape, and as a result, the obtained toner sometimes has a large variation in particle size and shape.
When such a toner is used in an image forming apparatus, the toner particles cannot be frictionally charged when a toner image is formed, which may cause a charging failure. As a result, when toner particles are electrostatically attached to the photosensitive drum, there is a risk of causing a transfer failure.

Japanese Patent Laid-Open No. 2004-070303

  An object of the present invention is to provide a method for producing resin fine particles, which can prevent the generation of hollow particles and irregular shaped particles, and can efficiently produce resin fine particles having a uniform shape and a small particle size distribution width. It is in.

Such an object is achieved by the present invention described below.
The method for producing resin fine particles of the present invention is a method for producing resin fine particles by discharging a dispersion in which a dispersoid mainly composed of a resin material is finely dispersed in an aqueous dispersion medium into droplets,
Removing the aqueous dispersion medium from the droplet-like dispersion by heating, and aggregating the plurality of dispersoids contained in the droplet-like dispersion to obtain an aggregate;
The heating temperature is 50 to 100 ° C., and
A resin having a glass transition point equal to or higher than the heating temperature is used as the resin material.
Accordingly, it is possible to prevent the aqueous dispersion medium from being rapidly removed and to prevent the fine particles derived from the dispersoid from being joined unintentionally when the aqueous dispersion medium is removed. As a result, the generation of hollow particles and irregularly shaped particles can be prevented more remarkably, and resin fine particles having a uniform shape and a narrow particle size distribution can be produced.

In the method for producing resin fine particles of the present invention, the glass transition point of the resin material is preferably 50 to 120 ° C.
Thereby, the aggregate which has moderate intensity | strength can be obtained, suppressing the unintentional joining of the dispersoids which comprise an aggregate more reliably.
In the method for producing resin fine particles of the present invention, the resin material preferably has a water absorption rate of 3.0 wt% or less.
As a result, the aqueous dispersion medium can be efficiently removed in a relatively short time, and as a result, the production efficiency of the resin fine particles can be improved.

In the method for producing resin fine particles of the present invention, it is preferable that the resin material is mainly composed of a thermosetting resin.
As a result, the fixing temperature can be lowered, and the fixing characteristics can be improved. Moreover, the heat resistance of the resin fine particles obtained can be improved.
In the method for producing resin fine particles of the present invention, the thermosetting resin is preferably an epoxy resin.
As a result, the fixing temperature can be lowered, and the fixing characteristics can be improved more effectively. Moreover, the heat resistance of the resin fine particles obtained can be improved.

In the method for producing resin fine particles of the present invention, it is preferable that the dispersion liquid is intermittently discharged by piezoelectric pulses.
Thereby, generation | occurrence | production of a hollow particle or irregularly shaped particle | grains can be prevented, and while having a uniform shape, the resin fine particle with a small width | variety of a particle size distribution can be manufactured more efficiently.
In the resin fine particle manufacturing method of the present invention, the head unit that discharges the dispersion includes a dispersion storage unit that stores the dispersion, and a piezoelectric that applies a piezoelectric pulse to the dispersion stored in the dispersion storage unit. It is preferable to have a body and a discharge unit that discharges the dispersion liquid by the piezoelectric pulse.
Thereby, generation | occurrence | production of a hollow particle or irregularly shaped particle | grains can be prevented, and while having a uniform shape, the resin fine particle with a small width | variety of a particle size distribution can be manufactured more efficiently.

In the method for producing resin fine particles of the present invention, the resin fine particles are preferably toner particles.
Thereby, a toner excellent in various properties such as durability and fixing properties can be provided.
The resin fine particles of the present invention are produced by the method for producing resin fine particles of the present invention.
Thereby, it is possible to provide resin fine particles having a uniform shape and a narrow particle size distribution.

In the resin fine particles of the present invention, the average particle size is preferably 2 to 20 μm.
As a result, for example, when resin fine particles are applied to the toner, the variation in characteristics such as charging characteristics and fixing characteristics among the toner particles is particularly small, and the reliability of the toner as a whole is particularly high. Thus, the resolution of the image formed can be made sufficiently high.

In the resin fine particles of the present invention, the water content is preferably 4.0 wt% or less.
Thereby, for example, when resin fine particles are applied to toner, it is possible to achieve excellent charging characteristics and durability.
In the resin fine particles of the present invention, the standard deviation of the particle size between the particles is preferably 1.5 μm or less.
Thereby, for example, when resin fine particles are applied to the toner, variations in characteristics such as charging characteristics and fixing characteristics among the toner particles are particularly reduced, and the reliability of the entire toner is further improved.

In the resin fine particles of the present invention, the average circularity R represented by the following formula (I) is preferably 0.95 or more.
R = L ₀ / L ₁ (I)
(Where, L ₁ [μm] is the circumference of the projected image of the resin fine particle to be measured, and L ₀ [μm] is the circumference of a perfect circle having an area equal to the area of the projected image of the resin fine particle to be measured) Represents length)
Thereby, for example, when resin fine particles are applied to the toner, variations in characteristics such as charging characteristics and fixing characteristics among the toner particles are particularly reduced, and the reliability of the entire toner is further improved.

In the resin fine particles of the present invention, the standard deviation of the average circularity between the particles is preferably 0.015 or less.
Thereby, for example, when resin fine particles are applied to the toner, variations in characteristics such as charging characteristics and fixing characteristics among the toner particles are particularly reduced, and the reliability of the entire toner is further improved.

In the resin fine particles of the present invention, the bulk density is preferably 0.34 g / cm ³ or more.
Thereby, for example, when resin fine particles are applied to toner, it is possible to achieve excellent charging characteristics and durability. Further, it is possible to increase the amount of toner filled in the cartridge of the same volume, and to reduce the size of the cartridge.

Hereinafter, preferred embodiments of the method for producing resin fine particles and the resin fine particles of the present invention will be described in detail with reference to the accompanying drawings. The resin fine particles obtained by the method for producing resin fine particles of the present invention may be any as long as they are mainly composed of a resin material. The resin fine particles are used for the production of toner particles or toner particles. Particles (eg, toner mother particles) are preferred. Among the various resin fine particles, the toner is required to have a more uniform size and shape uniformity among the particles, and the effect of applying the present invention is particularly remarkable. Therefore, in the following description, toner particles will be representatively described as an example of resin fine particles. In the present specification, “resin fine particles” refers to particles (powder) mainly composed of a resin material, and may include components other than the resin material.
FIG. 1 is a longitudinal sectional view schematically showing a first embodiment of a resin fine particle production apparatus used for production of resin fine particles of the present invention, and FIG. 2 is an enlarged view of the vicinity of the head portion of the resin fine particle production apparatus shown in FIG. It is sectional drawing.

[Dispersion]
First, the dispersion 6 used in the present invention will be described. The resin fine particles of the present invention are produced using the dispersion liquid 6. Examples of the dispersion include suspensions (suspensions) and emulsions (emulsions, emulsions, and emulsions). In this specification, “suspension” refers to a dispersion (including suspension colloid) in which a solid (solid) dispersoid (suspension particles) is dispersed in a liquid aqueous dispersion medium. The “emulsion (emulsion, emulsion, emulsion)” refers to a dispersion in which a liquid dispersoid (dispersed particles) is dispersed in an aqueous dispersion medium. In the dispersion liquid, a solid dispersoid and a liquid dispersoid may coexist. In such a case, among the dispersoids in the dispersion, those in which the proportion of the solid dispersoid is larger than the proportion of the liquid dispersoid is called a suspension, and the proportion of the liquid dispersoid is solid. What is larger than the proportion of the dispersoid in the form of a powder is called an emulsion. In particular, it is preferable that the dispersion used in the present invention has been deaerated. The deaeration process will be described in detail later.
The dispersion 6 has a configuration in which a dispersoid (dispersed phase) 61 is finely dispersed in an aqueous dispersion medium 62.

<Aqueous dispersion medium>
The aqueous dispersion medium 62 is mainly composed of water. Thereby, for example, the dispersibility of the dispersoid 61 in the aqueous dispersion medium 62 can be enhanced, and the dispersoid 61 in the dispersion 6 has a relatively small particle size and a small variation in size. can do. As a result, the finally obtained toner (toner particles) is small in size and shape variation between particles and has a large circularity. In particular, the organic solvent can be substantially prevented from volatilizing in the toner manufacturing process. As a result, the toner can be produced by a method that hardly causes adverse effects on the environment, that is, an environmentally friendly method.

The aqueous dispersion medium 62 only needs to be mainly composed of water. Specifically, the water content is preferably 50 wt% or more, more preferably 60 to 99 wt%, and 70 More preferably, it is -99 wt%. Thereby, the above-mentioned effect becomes more remarkable.
The aqueous dispersion medium 62 may contain components other than water. For example, a liquid excellent in compatibility with water (for example, a liquid having a solubility in 100 g of water at 25 ° C. of 30 g or more) may be included. Thereby, the dispersibility of the dispersoid 61 mentioned later can be improved, for example.
Further, the aqueous dispersion medium 62 may contain components other than the above-described materials. For example, in the aqueous dispersion medium 62, materials exemplified later as constituents of the dispersoid 61, inorganic fine powders such as silica, titanium oxide, and iron oxide, organic fine powders such as fatty acids and fatty acid metal salts, etc. Various additives and the like may be included.

<Dispersed quality>
The dispersoid 61 is usually made of a material containing at least a resin as a main component or a precursor thereof (hereinafter collectively referred to as “resin material”). Examples of the resin precursor include a monomer, a dimer, and an oligomer of the resin.
Hereinafter, the constituent material of the dispersoid 61 will be described.

1. Resin (binder resin)
In the present invention, the binder resin is characterized in that its glass transition point is higher than the heating temperature in the dispersion medium removing step described in detail later. In other words, the present invention is characterized in that the relationship of Tg ≧ Td is satisfied, where Tg is the glass transition point of the binder resin and Td is the heating temperature. Thereby, in the dispersion medium removal process mentioned later, the aggregate 9 which has moderate intensity | strength can be obtained, suppressing the unintentional joining of the dispersoid 61 which comprises the aggregate 9.

In the present invention, when the glass transition point of the binder resin is Tg and the heating temperature is Td, it is characterized by satisfying the relationship of Tg ≧ Td, but it is preferable to satisfy the relationship of Tg ≧ Td + 5, It is more preferable to satisfy the relationship of Td + 5 ≦ Tg ≦ Td + 20. Thereby, the effect of this invention becomes remarkable.
On the other hand, when the glass transition point of the binder resin is less than the lower limit, it is difficult to suppress unintentional bonding between the dispersoids 61 constituting the aggregate 9 in the dispersion medium removing step described later. It becomes.

  Specifically, the glass transition point of the resin constituting the dispersoid 61 is preferably 50 to 120 ° C. Thereby, in the dispersion medium removal process mentioned later, the aggregate 9 which has moderate intensity | strength can be obtained, suppressing the unintentional joining of the dispersoid 61 which comprises the aggregate 9 more reliably. Moreover, the suitable aggregate 9 can be obtained efficiently. When the resin material constituting the dispersoid 61 is composed of a plurality of types of resin materials (resin components), the glass of the resin (component) constituting the main component of the dispersoid 61 as the glass transition point of the resin. Adopt a transition point.

  Moreover, it is preferable that melting | fusing point of resin which comprises the dispersoid 61 is 90-200 degreeC. Thereby, for example, when resin fine particles are applied to toner particles, the fixing characteristics can be improved. When the resin material constituting the dispersoid 61 is composed of a plurality of types of resin materials (resin components), the melting point of the resin (component) constituting the main component of the dispersoid 61 is adopted as the melting point of the resin. To do.

  Examples of the resin (binder resin) include (meth) acrylic resin, polycarbonate resin, polystyrene, poly-α-methylstyrene, chloropolystyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene- Butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-acrylic Styrene resin such as acid ester-methacrylic acid ester copolymer, styrene-α-methyl chloroacrylate copolymer, styrene-acrylonitrile-acrylic acid ester copolymer, styrene-vinyl methyl ether copolymer A homopolymer containing a substituent, or Is a copolymer, polyester resin, epoxy resin, urethane modified epoxy resin, silicone modified epoxy resin, vinyl chloride resin, rosin modified maleic acid resin, phenyl resin, polyethylene, polypropylene, ionomer resin, polyurethane resin, silicone resin, ketone resin, Examples include ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral resin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, and one or a combination of two or more of these may be used. it can. In addition, when a toner is manufactured by polymerizing a raw material in the dispersoid 61 in a solidification section of a toner manufacturing apparatus described later, the above-mentioned resin material monomers, dimers, oligomers and the like are usually used.

Among the resins described above, when a thermosetting resin is used as a constituent material of the dispersoid 61, even when a resin having a relatively high glass transition point is used, the temperature range at which the resin is softened is compared. Therefore, the fixing temperature can be lowered and the fixing characteristics can be improved. Moreover, since the thermosetting resin generally has a low water absorption rate, the aqueous dispersion medium 62 can be removed relatively easily. Further, when the thermosetting resin is used, the binder resin can be cured on the recording medium, so that the adhesion is improved and the fixing strength can be improved.
In particular, among the thermosetting resins, when an epoxy resin is used, the above-described effect becomes more remarkable.

The water absorption obtained by the JISK7209 B method of the resin constituting the dispersoid 61 is preferably 3.0 wt% or less, and more preferably 0.01 to 1.0 wt%. Thereby, the removal of the aqueous dispersion medium 62 can be performed efficiently and in a relatively short time, and as a result, the production efficiency of the resin fine particles can be improved. On the other hand, if the water absorption rate exceeds the upper limit, it may be difficult to sufficiently remove the aqueous dispersion medium in the dispersion medium removal step described later, and the production efficiency of the resin fine particles is reduced. There is.
The content of the resin in the dispersoid 61 is not particularly limited, but is preferably 2 to 98 wt%, more preferably 5 to 95 wt%.
In addition, the resin mentioned above may contain the hardening | curing agent etc. as needed.

2. Solvent The dispersoid 61 may contain a solvent that dissolves at least a part of its components. Thereby, for example, the fluidity of the dispersoid 61 in the dispersion liquid 6 can be improved, and the dispersoid 61 in the dispersion liquid 6 has a relatively small particle size and small variation in size. be able to. As a result, the finally obtained toner (toner particles) is small in size and shape variation between particles and has a large circularity.
Any solvent can be used as long as it dissolves at least a part of the components constituting the dispersoid 61. However, the solvent can be easily removed in a solidifying part of a toner production apparatus as described later. Preferably there is.

The solvent is preferably a solvent having low compatibility with the aqueous dispersion medium 62 described above (for example, a solvent having a solubility in 100 g of the aqueous dispersion medium at 25 ° C. of 30 g or less). Thereby, the dispersoid 61 can be finely dispersed in the dispersion 6 in a stable state.
Moreover, the composition of the solvent can be appropriately selected according to, for example, the composition of the resin and the colorant described above, the composition of the aqueous dispersion medium, and the like.

  Examples of the solvent include inorganic solvents such as carbon disulfide and carbon tetrachloride, methyl ethyl ketone (MEK), acetone, diethyl ketone, methyl isobutyl ketone (MIBK), methyl isopropyl ketone (MIPK), cyclohexanone, 3-heptanone, 4 -Ketone solvents such as heptanone, methanol, ethanol, n-propanol, isopropanol, n-butanol, i-butanol, t-butanol, 3-methyl-1-butanol, 1-pentanol, 2-pentanol, n- Alcohol solvents such as hexanol, cyclohexanol, 1-heptanol, 1-octanol, 2-octanol, 2-methoxyethanol, allyl alcohol, furfuryl alcohol, phenol, diethyl ether, dipropyl ether, diisopropyl Ether solvents such as ether, dibutyl ether, 1,2-dimethoxyethane (DME), 1,4-dioxane, tetrahydrofuran (THF), tetrahydropyran (THP), anisole, diethylene glycol dimethyl ether (diglyme), 2-methoxyethanol, Cellosolve solvents such as methyl cellosolve, ethyl cellosolve, phenyl cellosolve, aliphatic hydrocarbon solvents such as hexane, pentane, heptane, cyclohexane, methylcyclohexane, octane, didecane, methylcyclohexene, isoprene, toluene, xylene, benzene, ethylbenzene, Aromatic hydrocarbon solvents such as naphthalene, pyridine, pyrazine, furan, pyrrole, thiophene, 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, fluoro Aromatic heterocyclic compound solvents such as furyl alcohol, amide solvents such as N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMA), dichloromethane, chloroform, 1,2-dichloroethane, trichloroethylene, chlorobenzene Halogenated solvents such as acetylacetone, ethyl acetate, methyl acetate, isopropyl acetate, isobutyl acetate, isopentyl acetate, ethyl chloroacetate, butyl chloroacetate, isobutyl chloroacetate, ethyl formate, isobutyl formate, ethyl acrylate, methyl methacrylate, Ester solvents such as ethyl benzoate, amine solvents such as trimethylamine, hexylamine, triethylamine and aniline, nitrile solvents such as acrylonitrile and acetonitrile, nitromethane, nitroethane, etc. Organic solvents such as aldehyde solvents such as nitro solvents, acetaldehyde, propionaldehyde, butyraldehyde, pentanal, and acrylic aldehyde, etc., and a mixture of one or more selected from these may be used. it can. Among these, those containing an organic solvent are preferred, and ether solvents, cellosolve solvents, aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, aromatic heterocyclic compounds solvents, amide solvents, halogen compound solvents. More preferably, the solvent contains one or more selected from a solvent, an ester solvent, a nitrile solvent, a nitro solvent, and an aldehyde solvent. By using such a solvent, the above-described components can be dispersed sufficiently uniformly in the dispersoid 61 relatively easily.

  In addition, the dispersion 6 usually contains a colorant. Examples of the colorant that can be used include pigments and dyes. Examples of such pigments and dyes include carbon black, spirit black, lamp black (CI No. 77266), magnetite, titanium black, chrome lead, cadmium yellow, mineral fast yellow, navel yellow, and naphthol yellow S. , Hansa Yellow G, Permanent Yellow NCG, Chrome Yellow, Benzidine Yellow, Quinoline Yellow, Tartrazine Lake, Red Mouth Lead, Molybdenum Orange, Permanent Orange GTR, Pyrazolone Orange, Benzidine Orange G, Cadmium Red, Permanent Red 4R, Watching Red Calcium salt, eosin lake, brilliant carmine 3B, manganese purple, fast violet B, methyl violet lake, bitumen, cobalt blue, al Reblue Lake, Victoria Blue Lake, First Sky Blue, Indanthrene Blue BC, Ultramarine, Aniline Blue, Phthalocyanine Blue, Calco Oil Blue, Chrome Green, Chrome Oxide, Pigment Green B, Malachite Green Lake, Phthalocyanine Green, Final Yellow Green G, Rhodamine 6G, quinacridone, rose bengal (C.I. No. 45432), C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Modern Tread 30, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 184, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modern Blue 7, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 5: 1, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Basic Green 6, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 180, C.I. I. Pigment Yellow 162, nigrosine dye (CI No. 50415B), metal complex dye, silica, aluminum oxide, magnetite, maghemite, various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, Examples thereof include metal oxides such as magnesium oxide, and magnetic materials containing magnetic metals such as Fe, Co, and Ni, and one or more of these can be used in combination. Such a colorant is usually contained in the dispersoid 61 in the dispersion liquid 6.

  The content of the colorant in the dispersion 6 is not particularly limited, but is preferably 0.1 to 10 wt%, and more preferably 0.3 to 3.0 wt%. If the content of the colorant is less than the lower limit, it may be difficult to form a visible image having a sufficient density depending on the type of the colorant. On the other hand, when the content of the colorant exceeds the upper limit, the fixing characteristics and charging characteristics of the finally obtained toner may be deteriorated.

  Further, the dispersion 6 may contain wax. The wax is usually used for the purpose of improving releasability. Examples of such wax include plant waxes such as candelilla wax, carnauba wax, rice wax, cotton wax, and wood wax, animal waxes such as beeswax and lanolin, montan wax, ozokerite, and ceresin. Mineral waxes such as mineral waxes, paraffin waxes, microwaxes, microcrystalline waxes, petroleum waxes such as petrolatum waxes, Fischer-Tropsch waxes, polyethylene waxes (polyethylene resins), polypropylene waxes (polypropylene resins) ), Synthetic hydrocarbon waxes such as oxidized polyethylene wax and oxidized polypropylene wax, 12-hydroxy stearamide, stearamide, phthalic anhydride, chlorinated hydrocarbon Fatty acid amides, esters, ketones, synthetic wax wax such as ether and the like, can be used singly or in combination of two or more of them. Further, as the wax, a crystalline polymer resin having a lower molecular weight may be used. For example, a homopolymer or copolymer of polyacrylate such as poly n-stearyl methacrylate and poly n-lauryl methacrylate (for example, It is also possible to use a crystalline polymer having a long alkyl group in the side chain, such as an n-stearyl acrylate-ethyl methacrylate copolymer).

  The wax content in the dispersion 6 is not particularly limited, but is preferably 1.0 wt% or less, and more preferably 0.5 wt% or less. If the content of the wax is too large, the wax is liberated and coarsened in the finally obtained toner particles, and the toner seeps into the toner particle surface and the transfer efficiency of the toner tends to decrease. Indicates.

The softening point of the wax is not particularly limited, but is preferably 50 to 180 ° C, and more preferably 60 to 160 ° C.
Further, the dispersion 6 may contain components other than these. Examples of such components include emulsifying dispersants, charge control agents, magnetic powders, and the like. Among these, when the emulsifying dispersant is used, for example, the dispersibility of the dispersoid 61 in the dispersion 6 can be improved. Here, examples of the emulsifying dispersant include emulsifiers, dispersants, and dispersion aids.

  Examples of the dispersant include inorganic dispersants such as tricalcium phosphate, nonionic organic dispersants such as polyvinyl alcohol, carboxymethyl cellulose, and polyethylene glycol, metal tristearate (for example, aluminum salt), and metal distearate. Salt (eg, aluminum salt, barium salt, etc.), stearic acid metal salt (eg, calcium salt, lead salt, zinc salt, etc.), linolenic acid metal salt (eg, cobalt salt, manganese salt, lead salt, zinc salt, etc.) , Octanoic acid metal salts (eg, aluminum salts, calcium salts, cobalt salts, etc.), oleic acid metal salts (eg, calcium salts, cobalt salts, etc.), palmitic acid metal salts (eg, zinc salts, etc.), naphthenic acid metal salts (For example, calcium salt, cobalt salt, manganese salt, lead salt, zinc salt, etc.), Resin metal salt (example Calcium salt, cobalt salt, manganese lead salt, zinc salt, etc.), polyacrylic acid metal salt (eg, sodium salt), polymethacrylic acid metal salt (eg, sodium salt), polymaleic acid metal salt (eg, Sodium salts, etc.), anionic organic dispersants such as acrylic acid-maleic acid copolymer metal salts (eg, sodium salts), polystyrene sulfonic acid metal salts (eg, sodium salts), etc., cations such as quaternary ammonium salts Organic dispersants and the like. Among these, nonionic organic dispersants or anionic organic dispersants are particularly preferable.

The content of the dispersant in the dispersion 6 is not particularly limited, but is preferably 3.0 wt% or less, and more preferably 0.01 to 1.0 wt%.
Examples of the dispersion aid include anions, cations, and nonionic surfactants.
The dispersing aid is preferably used in combination with a dispersing agent. When the dispersion 6 contains a dispersant, the content of the dispersion aid in the dispersion 6 is not particularly limited, but is preferably 2.0 wt% or less, and is 0.005 to 0.5 wt%. Is more preferable.

Examples of the charge control agent include a metal salt of benzoic acid, a metal salt of salicylic acid, a metal salt of alkyl salicylic acid, a metal salt of catechol, a metal-containing bisazo dye, a nigrosine dye, a tetraphenylborate derivative, a quaternary ammonium salt, Examples thereof include alkyl pyridinium salts, chlorinated polyesters, and nitrohumic acid.
Examples of the magnetic powder include magnetite, maghemite, various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, magnesium oxide, and other metal oxides such as Fe, Co, and Ni. The thing comprised with the magnetic material containing a magnetic metal etc. are mentioned.

In addition to the above materials, for example, zinc stearate, zinc oxide, cerium oxide or the like may be added to the dispersion liquid 6.
In addition, components other than the dispersoid 61 may be dispersed in the dispersion 6 as insoluble matters. For example, in the dispersion 6, inorganic fine powders such as silica, titanium oxide, and iron oxide, organic fine powders such as fatty acids and fatty acid metal salts, and the like may be dispersed.

In the dispersion 6, the dispersoid 61 is finely dispersed in the aqueous dispersion medium 62.
Although the average particle diameter of the dispersoid 61 in the dispersion liquid 6 is not specifically limited, It is preferable that it is 0.05-1.0 micrometer, and it is more preferable that it is 0.1-0.8 micrometer. When the average particle size of the dispersoid 61 is in such a range, the finally obtained toner particles have a sufficiently high circularity and excellent properties and uniformity in shape among the particles. Become.

The content of the dispersoid 61 in the dispersion 6 is not particularly limited, but is preferably 1 to 99 wt%, more preferably 5 to 95 wt%. When the content of the dispersoid 61 is less than the lower limit, the circularity of the finally obtained toner particles tends to decrease. On the other hand, when the content of the dispersoid 61 exceeds the upper limit, depending on the composition of the aqueous dispersion medium 62 and the like, the viscosity of the dispersion 6 becomes high, and the shape and size of the finally obtained toner (toner particles). This shows a tendency that the variation of
In the dispersion 6, the dispersoid 61 may be in a solid form, in a liquid form, or may coexist. That is, the dispersion 6 may be a suspension or an emulsion.

  When the dispersoid 61 is liquid (for example, in a solution state or a molten state), the average particle diameter of the dispersoid 61 finely dispersed in the aqueous dispersion medium 62 is relatively easily set to a value in the above range. Can be. Further, when the dispersoid 61 is in a liquid form, variation in shape and size between the dispersoids 61 can be made particularly small, so that the finally obtained toner is between the toner particles. The variation in shape and size is particularly small.

Further, when the dispersoid 61 is solid, unnecessary components such as a solvent can be effectively prevented from remaining in the finally obtained toner. As a result, the reliability of the toner is particularly excellent. When the dispersoid 61 is solid, that is, when the dispersion 6 is a suspension, for example, the suspension as the dispersion 6 is prepared via an emulsion. There may be. Thereby, the advantage in the case where the dispersoid 61 is in a liquid state is also effectively exhibited while sufficiently exhibiting the advantage in the case where the dispersoid 61 is in a solid state as described above.
Further, the dispersoid 61 dispersed in the aqueous dispersion medium 62 may have, for example, substantially the same composition or different composition among the respective particles. For example, the dispersion 6 may include, as the dispersoid 61, one mainly composed of a resin material and one mainly composed of wax.

  Further, when the dispersion liquid 6 is an emulsion liquid (emulsion), the dispersion liquid 6 is an O / W type emulsion, that is, a liquid having a low solubility in water in the aqueous dispersion medium 62. The dispersoid 61 is preferably dispersed. As a result, a toner having a small variation in shape and size between the particles can be stably produced. Further, by using an aqueous liquid as the aqueous dispersion medium 62, it is possible to reduce the volatilization amount of the organic solvent in the solidification part of the toner manufacturing apparatus as described later or to substantially not volatilize the organic solvent. As a result, the toner can be manufactured by a method that hardly causes adverse effects on the environment.

  Further, when the average particle size of the dispersoid 61 in the dispersion 6 is Dm [μm] and the average particle size of the toner particles is Dt [μm], the relationship of 0.005 ≦ Dm / Dt ≦ 0.5 is satisfied. It is preferable to satisfy the relationship of 0.01 ≦ Dm / Dt ≦ 0.2. By satisfying such a relationship, a toner having a particularly small variation in shape and size among the particles can be obtained.

The dispersion 6 as described above can be prepared using, for example, the following method (first method).
First, an aqueous solution in which a dispersant and / or an aqueous dispersion medium is added to a liquid mainly composed of water as necessary is prepared.
On the other hand, a resin liquid containing a resin as a main component of the toner or a precursor thereof (hereinafter collectively referred to as “resin material”) is prepared. For the preparation of the resin liquid, for example, the above-described solvent may be used in addition to the resin material. The resin liquid may be a molten liquid obtained by heating a resin material.

  Next, the resin liquid is gradually added dropwise to the stirred aqueous solution, whereby the dispersion 6 in which the dispersoid 61 containing the resin material is dispersed in the aqueous aqueous dispersion medium 62 is obtained. Is obtained. By preparing the dispersion 6 by such a method, the circularity of the dispersoid 61 in the dispersion 6 can be further increased. As a result, the finally obtained toner particles have a particularly high degree of circularity and a particularly small variation in shape between the particles. In addition, when dripping a resin liquid, you may heat an aqueous solution and / or a resin liquid. In addition, when a solvent is used for the preparation of the resin liquid, for example, after the dropwise addition as described above, the obtained dispersion liquid 6 is heated or placed in a reduced-pressure atmosphere or the like in the dispersoid 61. You may remove at least one part of the solvent contained. For example, the dispersion 6 can be obtained as a suspension by removing most of the solvent contained in the dispersoid 61.

As mentioned above, although the example of the preparation method of the dispersion liquid 6 was demonstrated, the dispersion liquid is not limited to what was prepared by such a method. For example, the dispersion liquid 6 can also be prepared by the following method (second method).
First, an aqueous solution in which a dispersant and / or an aqueous dispersion medium is added to a liquid mainly composed of water as necessary is prepared.
On the other hand, a powdery or granular material containing a resin material is prepared.
Next, this powdery or granular material is gradually introduced into an agitated aqueous solution, whereby a dispersoid 61 containing a resin material is dispersed in an aqueous aqueous dispersion medium 62. Liquid 6 is obtained. When the dispersion liquid 6 is prepared by such a method, it is possible to substantially prevent the organic solvent from volatilizing in the solidifying part of the toner manufacturing apparatus as described later. As a result, the toner can be manufactured by a method that hardly causes adverse effects on the environment. In addition, when adding the said material, you may heat an aqueous solution, for example.

The dispersion 6 can also be prepared by the following method (third method).
First, a resin dispersion in which at least a resin material is dispersed and a colorant dispersion in which at least a colorant is dispersed are prepared.
Next, the resin dispersion and the colorant dispersion are mixed and stirred. At this time, if necessary, an aggregating agent such as an inorganic metal salt may be added while stirring.
By stirring for a predetermined time, an aggregate in which the resin material, the colorant and the like are aggregated is formed. As a result, a dispersion 6 in which the aggregate is dispersed as the dispersoid 61 is obtained.

  In the method for preparing a dispersion as described above, a kneaded material containing a resin material (binder resin) may be used. That is, as the “resin material” in the first method and the third method described above, a kneaded material containing a resin material may be used, or as the “powdered or granular material” in the second method, A kneaded material containing a resin material may be used. Thereby, for example, toner particles can be obtained as a mixture in which each constituent component is more uniformly mixed. In particular, even when the toner includes two or more components having poor dispersibility and compatibility, the above-described effects can be obtained. In addition, as a kneaded material, what contains components (for example, components, such as a coloring agent, a wax, a charge control agent) other than a resin component, for example can be used. Thereby, the above effects become more remarkable.

  Further, for example, the method described in Japanese Patent Application No. 2003-113428 may be applied to the preparation of the dispersion liquid 6. That is, a liquid containing a powdered or granular resin material (kneaded material) is ejected from a plurality of nozzles, the liquids ejected from the nozzles collide with each other, and the resin material (kneaded material) is atomized to form fine particles. A method of obtaining the dispersion 6 containing the dispersed dispersoid 61 may be applied. Thereby, the size of the dispersoid 61 contained in the dispersion liquid 6 can be easily made relatively small (the size in the above-described range), and the dispersion of the sizes of the dispersoids 61 can be easily achieved. Can be reduced.

  Further, it is preferable that the dispersion 6 obtained by the above method is subjected to a degassing treatment (subjected to a degassing step) before being used for discharge in a toner manufacturing apparatus described later. Thereby, the dissolved amount of the gas in the dispersion liquid 6 can be reduced, and when the aqueous dispersion medium 62 is removed from the dispersion liquid 6 ejected in the form of droplets in the solidification part of the toner manufacturing apparatus described later. It is possible to effectively prevent bubbles and the like from being generated in the dispersion 6. As a result, it is possible to effectively prevent toner particles having irregular shapes (hollow particles, missing particles, etc.) from being mixed into the finally obtained toner. Therefore, it is possible to easily and reliably obtain a toner in which each toner particle has a uniform shape and a narrow particle size distribution. Thereby, the finally obtained toner can be made particularly excellent in properties such as transferability, fluidity, and cleaning properties. Further, by subjecting the dispersion liquid 6 to deaeration treatment, the ratio of pores (voids) in the finally obtained toner particles can be reduced. As a result, the reliability of the toner is further improved.

The method of deaeration treatment is not particularly limited, and for example, a method of applying ultrasonic vibration to the dispersion (ultrasonic vibration method), a method of placing the dispersion in a reduced-pressure atmosphere (decompression method), or the like can be used. .
When the decompression method is used as the degassing method, the pressure of the atmosphere in which the dispersion is placed is preferably 80 kPa or less, more preferably 0.1 to 40 kPa, and further preferably 1 to 27 kPa. preferable. If the atmospheric pressure during the degassing treatment is within this range, the dissolved gas can be efficiently removed while maintaining the shape of the dispersoid 61 in the dispersion 6 sufficiently.

Next, the method for producing resin fine particles of the present invention will be described.
First, the resin fine particle manufacturing apparatus used in the present invention will be described with reference to the accompanying drawings.
In the following description, a case where the method for producing resin fine particles of the present invention is applied to toner production will be described.

The resin fine particle manufacturing apparatus 1 includes a head unit 2 that discharges the above-described dispersion liquid 6 (particularly, the dispersion liquid 6 that has been degassed), a dispersion liquid supply section 4 that supplies the dispersion liquid 6 to the head section 2, It has the solidification part 3 in which the dispersion liquid 6 discharged from the head part 2 is conveyed, and the collection | recovery part 5 which collect | recovers the aggregates 9. FIG.
A dispersion liquid 6 to be described later is stored in the dispersion liquid supply unit 4, and the dispersion liquid 6 is sent to the head unit 2.

The dispersion liquid supply unit 4 may have any function as long as it has a function of supplying the dispersion liquid 6 to the head unit 2. Alternatively, the dispersion liquid supply unit 4 may have stirring means 41 for stirring the dispersion liquid 6 as illustrated. Thereby, for example, even when the dispersoid 61 is difficult to disperse in the aqueous dispersion medium, the dispersion 6 in which the dispersoid 61 is sufficiently uniformly dispersed can be supplied into the head unit 2.
The head unit 2 includes a dispersion liquid storage unit 21, a piezoelectric element 22, and a discharge unit 23.
The dispersion liquid storage section 21 stores the dispersion liquid 6 as described above.
The dispersion 6 stored in the dispersion storage part 21 is discharged from the discharge part 23 to the solidification part 3 by the pressure pulse (piezoelectric pulse) of the piezoelectric element 22.
The droplet-like dispersion liquid 6 discharged to the solidifying unit 3 is conveyed through the solidifying unit 3.

In the present embodiment, the aqueous dispersion medium 62 is removed in the step of transporting the solidification unit 3 (transport step).
That is, the droplet-like dispersion liquid 6 discharged to the solidification unit 3 is heated by the atmosphere in the solidification unit 3 while being transported through the solidification unit 3, and the aqueous dispersion medium 62 is removed and solidified. As a result, an aggregate (toner particle) 9 is formed by aggregating a plurality of fine particles derived from the dispersoid 61 (dispersion medium removing step).

In the present invention, the temperature of the atmosphere in the solidifying unit 3 is maintained at 50 to 100 ° C. during the production of the toner. That is, the droplet-like dispersion 6 discharged from the head unit 2 is heated at a temperature of 50 to 100 ° C. in the solidifying unit 3.
As described above, in the present invention, the dispersion discharged in the solidification part is heated (dried) at the above-described temperature, thereby sufficiently removing the aqueous dispersion medium in the discharged dispersion and generating hollow particles. Can be prevented.

As described above, the present invention is characterized in that the liquid dispersion 6 discharged from the head unit 2 is heated in the solidification unit 3 at a temperature of 50 to 100 ° C., but at 50 to 90 ° C. It is preferable that it is 50 to 80 ° C. Thereby, the effect of this invention becomes remarkable.
On the other hand, if the heating temperature is less than the lower limit, it takes time to sufficiently remove the aqueous dispersion medium in the discharged dispersion, and the productivity is lowered. In addition, in order to sufficiently remove the aqueous dispersion medium, it is necessary to lengthen the solidified portion, leading to an increase in the size of the apparatus. On the other hand, when the heating temperature exceeds the upper limit, the rate at which the aqueous dispersion medium is removed becomes higher than the rate at which the dispersoid aggregates, and a hollow portion is formed in the resulting aggregate.

By the way, conventionally, attempts have been made to obtain toner particles by solidifying liquid droplets of a raw material for toner production.
However, in the conventional method, when the dispersion medium is removed from the dispersion liquid, the dispersion medium is heated at a relatively high temperature. Therefore, the speed at which the dispersion medium is removed is larger than the speed at which the fine particles derived from the dispersoids aggregate. In some cases, hollow portions were formed in the toner particles. In particular, when the droplet is heated at a temperature higher than the glass transition point of the resin constituting the dispersoid, the fine particles are unintentionally joined before the fine particles derived from the dispersoid aggregate, In some cases, the formation of the hollow portion was further accelerated. In addition, when the toner is joined unintentionally in this way, the obtained aggregate has an irregular shape, and as a result, the obtained toner may have a large variation in particle size and shape. . Further, when the dispersion liquid was used, the dispersoid that spread in the droplets due to the bumping of the dispersion medium did not readily return to its original shape, and it was easy to form an irregular shape. In particular, in the conventional method, no consideration has been given to the relationship between the glass transition point of the binder resin and the temperature at which the dispersion medium is removed.

The present invention is characterized in that a certain regularity is found by paying attention to the relationship between the glass transition point of the binder resin and the temperature at which the dispersion medium is removed.
That is, in the method for producing resin fine particles of the present invention, the point of removing the aqueous dispersion medium by heating at a temperature of 50 to 100 ° C. and the point of using a binder resin having a glass transition point above the heating temperature. It is characterized by being satisfied at the same time. By satisfying these conditions at the same time, it is possible to prevent the aqueous dispersion medium from being removed suddenly and to prevent the particles from the dispersoid from joining unintentionally when the aqueous dispersion medium is removed. can do. As a result, the generation of hollow particles and irregularly shaped particles can be prevented more remarkably, and resin fine particles having a uniform shape and a narrow particle size distribution can be produced.
Such an effect cannot be obtained only by satisfying one of the above-described features.

The solidified portion 3 is configured by a cylindrical housing 31.
For the purpose of maintaining the temperature in the housing 31 (solidification unit 3) at the above-described temperature, for example, a heat source or a cooling source is installed inside or outside the housing 31, or the housing 31 is provided with a flow path for the heat medium or the cooling medium. It is good also as a formed jacket.
In the illustrated configuration, the pressure in the housing 31 is adjusted by the pressure adjusting means 12. As described above, by adjusting the pressure in the housing 31, the aqueous dispersion medium 62 in the discharged dispersion liquid 6 can be efficiently removed, and the toner productivity is improved. In the configuration shown in the figure, the pressure adjusting means 12 is connected to the housing 31 by a connecting pipe 121. Further, an enlarged diameter portion 122 having an enlarged inner diameter is formed in the vicinity of the end portion of the connection pipe 121 connected to the housing 31, and a filter 123 for preventing suction of the aggregate 9 and the like is further provided. ing.

Further, in the above description, it is assumed that the dispersoid 61 in the granular dispersion 6 is aggregated and the aggregate 9 is obtained by removing the aqueous dispersion medium 62 from the dispersion 6 in the solidification unit 3. However, the aggregate 9 is not limited to the one obtained in this way. For example, when the dispersoid 61 contains a precursor of a resin material (for example, a monomer, dimer, oligomer, or the like corresponding to the resin material), the polymerization reaction proceeds in the solidification unit 3 along with the removal of the aqueous dispersion medium 61. By doing so, a method of obtaining the aggregate 9 may be used. In other words, the constituent material of the aggregate 9 may be substantially the same as or different from the constituent material of the dispersoid 61.
The housing 31 is connected to voltage applying means 8 for applying a voltage. By applying a voltage having the same polarity as that of the granular dispersion 6 (aggregate 9) to the inner surface side of the housing 31 by the voltage applying means 8, the following effects can be obtained.

  Usually, the toner particles and the aggregate 9 as a production intermediate thereof are positively or negatively charged. For this reason, if there is a charged substance charged with a polarity different from that of the aggregate 9 (dispersion 6), a phenomenon occurs in which the aggregate 9 is electrostatically attracted and attached to the charged substance. On the other hand, if there is a charged substance charged with the same polarity as the aggregate 9, the charged substance and the aggregate 9 repel each other, effectively preventing the phenomenon that the aggregate 9 adheres to the surface of the charged substance. be able to. Therefore, by applying a voltage having the same polarity as that of the granular dispersion liquid 6 (aggregate 9) to the inner surface side of the housing 31, it is effective that the dispersion liquid 6 (aggregate 9) adheres to the inner surface of the housing 31. Can be prevented. Thereby, generation | occurrence | production of the toner powder of irregular shape can be prevented more effectively, and the collection | recovery efficiency of the aggregate 9 also improves.

  The housing 31 has a reduced diameter portion 311 in the vicinity of the collecting portion 5 that decreases in inner diameter in the downward direction in FIG. By forming such a reduced diameter portion 311, it is possible to efficiently collect the aggregate 9. As described above, the dispersion 6 discharged from the discharge unit 23 is solidified in the solidification unit 3 (becomes an aggregate 9), but in the vicinity of the recovery unit 5, such a solidification (aggregate) is obtained. 9) is almost completely completed, and in the vicinity of the reduced diameter portion 311, problems such as agglomeration hardly occur even if the respective particles come into contact with each other.

Although the shape of the discharge part 23 is not specifically limited, It is preferable that it is a substantially circular shape. Thereby, the sphericity of the discharged dispersion liquid 6, the aggregate 9 formed in the solidified portion, and the toner particles finally obtained can be increased.
When the discharge part 23 is a substantially circular shape, the diameter (nozzle diameter) is, for example, preferably 5 to 500 μm, and more preferably 10 to 200 μm. When the diameter of the discharge part 23 is less than the lower limit value, clogging is likely to occur, and the dispersion of the size of the discharged dispersion liquid 6 may increase. On the other hand, when the diameter of the discharge part 23 exceeds the upper limit, the discharged dispersion liquid 6 may entrap bubbles depending on the force relationship between the negative pressure of the dispersion liquid storage part 21 and the surface tension of the nozzle. There is sex.

  Further, the vicinity of the discharge portion 23 of the head portion 2 (particularly, the inner surface of the opening of the discharge portion 23 and the surface on the side where the discharge portion 23 of the head portion 2 is provided (the lower surface in the figure)) is a dispersion liquid. 6 preferably has liquid repellency. Thereby, it can prevent effectively that the dispersion liquid 6 adheres to the discharge part vicinity. As a result, it is possible to effectively prevent a so-called poor liquid runout or a discharge failure of the dispersion 6. Further, by effectively preventing the dispersion liquid 6 from adhering to the vicinity of the discharge portion, the stability of the shape of the discharged droplets is improved (the variation in shape and size between the droplets is small). The variation in the shape and size of the toner particles finally obtained is also reduced.

Examples of such a material having liquid repellency include fluorine resins such as polytetrafluoroethylene (PTFE), silicone materials, and the like.
Further, the vicinity of the discharge portion 23 of the head portion 2 (particularly, the inner surface of the opening of the discharge portion 23 and the surface on the side where the discharge portion 23 of the head portion 2 is provided (the lower surface in the drawing)) is hydrophobized. It is preferable that the treatment is performed. Thereby, for example, when the aqueous dispersion medium 62 of the dispersion 6 is mainly composed of water, the above-described liquid repellency can be more suitably exhibited, and the above-described effects can be further improved. Appear as prominent. Examples of the hydrophobic treatment method include formation of a film made of a hydrophobic material (for example, the above-described material having liquid repellency). By the way, although water has a relatively high viscosity among various liquids, even if such water is used as a constituent material of the aqueous dispersion medium 62, the dispersion liquid 6 adheres to the vicinity of the discharge portion, etc. The occurrence of inconvenience is effectively prevented. Therefore, when the hydrophobic treatment is performed in the vicinity of the discharge portion 23 of the head portion 2, the dispersion liquid 6 substantially not containing or hardly containing an organic solvent can be suitably used. The toner can be produced by a method that hardly causes an adverse effect.

As shown in FIG. 2, the piezoelectric element 22 includes a lower electrode (first electrode) 221, a piezoelectric body 222, and an upper electrode (second electrode) 223 that are stacked in this order. In other words, the piezoelectric element 22 has a configuration in which the piezoelectric body 222 is interposed between the upper electrode 223 and the lower electrode 221.
The piezoelectric element 22 functions as a vibration source, and the diaphragm 24 vibrates due to the vibration of the piezoelectric element (vibration source) 22 and has a function of instantaneously increasing the internal pressure of the dispersion liquid storage unit 21. It is.

  The head unit 2 is in a state where a predetermined ejection signal is not input from a piezoelectric element driving circuit (not shown), that is, a state where no voltage is applied between the lower electrode 221 and the upper electrode 223 of the piezoelectric element 22. Then, the piezoelectric body 222 is not deformed. For this reason, the diaphragm 24 is not deformed and the volume of the dispersion liquid storage unit 21 is not changed. Therefore, the dispersion 6 is not discharged from the discharge unit 23.

  On the other hand, in a state where a predetermined ejection signal is input from the piezoelectric element driving circuit, that is, in a state where a predetermined voltage is applied between the lower electrode 221 and the upper electrode 223 of the piezoelectric element 22, the piezoelectric body 222 is deformed. Arise. As a result, the diaphragm 24 is greatly deflected (bends downward in FIG. 2), and the volume of the dispersion liquid storage unit 21 is reduced (changed). At this time, the pressure in the dispersion liquid storage unit 21 increases instantaneously, and the granular dispersion liquid 6 is discharged from the discharge unit 23.

  When one discharge of the dispersion liquid 6 is completed, the piezoelectric element driving circuit stops applying the voltage between the lower electrode 221 and the upper electrode 223. Thereby, the piezoelectric element 22 returns almost to its original shape, and the volume of the dispersion liquid storage unit 21 increases. At this time, a pressure (pressure in the positive direction) acting from the dispersion liquid supply unit 4 to the discharge unit 23 acts on the dispersion liquid 6. For this reason, air is prevented from entering the dispersion liquid storage part 21 from the discharge part 23, and an amount of the dispersion liquid 6 corresponding to the discharge amount of the dispersion liquid 6 is supplied from the dispersion liquid supply part 4 to the dispersion liquid storage part 21. The

By applying the voltage as described above at a predetermined cycle, the piezoelectric element 22 vibrates and the granular dispersion liquid 6 is repeatedly discharged.
In this way, by performing discharge (injection) of the dispersion liquid 6 with the pressure pulse generated by the vibration of the piezoelectric body 222, the dispersion liquid 6 can be intermittently discharged one by one, and the discharged dispersion liquid 6 can be discharged. The shape of is stable. As a result, it is possible to obtain resin fine particles (toner) having small variations in shape and size between the respective particles (each toner particle) and to produce toner particles having high sphericity (geometrically). It is relatively easy to achieve a shape close to a perfect sphere.

Further, by discharging (injecting) the dispersion liquid as described above, the vibration frequency of the piezoelectric body, the opening area (nozzle diameter) of the discharge portion, the temperature / viscosity of the dispersion liquid, the discharge amount of one drop of the dispersion liquid, The content of the dispersoid in the dispersion and the particle size of the dispersoid in the dispersion can be controlled relatively accurately, making it easy to control the toner to be manufactured to the desired shape and size. it can. Further, by controlling these conditions and the like, for example, the production amount of toner and the like can be easily and reliably managed.
Further, by using the vibration of the piezoelectric body for discharging the dispersion liquid, the dispersion liquid can be discharged more reliably at a predetermined interval. For this reason, it can prevent effectively that the granular dispersion liquid discharged collides and aggregates, and can prevent the formation of irregular-shaped powder more effectively.

The initial velocity of the dispersion 6 discharged from the head unit 2 to the solidifying unit 3 is, for example, preferably 0.1 to 10 m / sec, and more preferably 2 to 8 m / sec. If the initial velocity of the dispersion 6 is less than the lower limit, the productivity of the aggregate 9 and toner is lowered. On the other hand, when the initial velocity of the dispersion liquid 6 exceeds the upper limit, the sphericity of the finally obtained toner particles tends to decrease.
Moreover, the viscosity of the dispersion 6 discharged from the head part 2 is not particularly limited, but is preferably 0.5 to 200 [mPa · s], for example, 1 to 25 [mPa · s]. Is more preferable. When the viscosity of the dispersion liquid 6 is less than the lower limit, it becomes difficult to sufficiently control the size of the discharged particles (granular dispersion liquid 6), and the dispersion of finally obtained toner particles becomes large. There is a case. On the other hand, when the viscosity of the dispersion 6 exceeds the upper limit, the diameter of the formed particles increases, the discharge speed of the dispersion 6 decreases, and the amount of energy required for discharging the dispersion 6 tends to increase. Show. In addition, when the viscosity of the dispersion liquid 6 is particularly large, the dispersion liquid 6 cannot be discharged as droplets.

Moreover, the temperature of the dispersion liquid 6 (dispersion liquid 6 in the head part 2) discharged from the head part 2 is not particularly limited, but is lower than the temperature in the solidification part 3 (processing temperature in the dispersion medium removing step). Is preferred. Thereby, it is possible to effectively prevent the aqueous dispersion medium 62 from volatilizing in the head portion 2 and the composition (concentration) of the discharged dispersion 6 from changing with time. In addition, the aqueous dispersion medium 62 volatilizes from the dispersion 6 immediately after spraying, so that the dispersion 6 can be effectively prevented from solidifying unintentionally. Specifically, in the vicinity of the discharge unit 23, it is effective to cause the discharge unit 23 to be clogged by volatilization of the aqueous dispersion medium 62 from the dispersion 6 before being discharged (before the liquid runs out). Can be prevented. In particular, the temperature of the dispersion liquid 6 (dispersion liquid 6 in the head section 2) discharged from the head section 2 is T ₀ [° C.], and the temperature in the solidification section 3 (treatment temperature in the dispersion medium removing step) is T _1. [° C], it is preferable to satisfy the relationship of −5 ≦ T ₁ −T ₀ ≦ 60, more preferably satisfy the relationship of −5 ≦ T ₁ −T ₀ ≦ 50, and 5 ≦ T _1. It is more preferable that the relationship of −T ₀ ≦ 40 is satisfied. By satisfying such a relationship, the above-described effects can be made more remarkable.

  Further, the dispersion 6 discharged from the head unit 2 may be preheated. By heating the dispersion 6 in this manner, for example, even if the dispersoid 61 is in a solid state (or a relatively high viscosity state) at room temperature, the dispersoid is in a molten state (or in discharge). (Viscosity is relatively low, softened state). As a result, in the solidification part 3 to be described later, the dispersoid 61 contained in the granular dispersion 6 is smoothly aggregated, and the resulting aggregate 9 has a particularly high circularity. As a result, finally, The resulting toner particles can also have a high degree of circularity.

  Further, the discharge amount of one drop of the dispersion 6 is slightly different depending on the content of the dispersoid 61 in the dispersion 6, but is preferably 0.05 to 500 pl, and more preferably 0.5 to 5 pl. Is more preferable. By setting the discharge amount of one drop of the dispersion 6 within such a range, the aggregate 9 can have an appropriate particle size. As a result, the finally obtained toner particles can also have an appropriate particle size.

  Incidentally, the granular dispersion liquid 6 discharged from the head unit 2 is generally sufficiently larger than the dispersoid 61 in the dispersion liquid 6. That is, a large number of dispersoids 61 are dispersed in the granular dispersion liquid 6. For this reason, even if the dispersion of the particle size of the dispersoid 61 is relatively large, the ratio of the dispersoid 61 in the discharged granular dispersion liquid 6 is almost uniform for each droplet. Therefore, even when the particle size variation of the dispersoid 61 is relatively large, the aggregate 9 obtained in this step has a small particle size variation by making the discharge amount of the dispersion 6 substantially uniform. It becomes. Such a tendency becomes more remarkable. For example, when the average particle diameter of the discharged dispersion liquid 6 is Dd [μm] and the average particle diameter of the dispersoid 61 in the dispersion liquid 6 is Dm [μm], the relationship of Dm / Dd <0.5 is satisfied. It is preferable to satisfy the relationship of Dm / Dd <0.2.

  Further, when the average particle size of the discharged dispersion 6 is Dd [μm] and the average particle size of the manufactured toner particles is Dt [μm], a relationship of 0.05 ≦ Dt / Dd ≦ 1.0 is established. It is preferable to satisfy, and it is more preferable to satisfy the relationship of 0.1 ≦ Dt / Dd ≦ 0.8. By satisfying such a relationship, a sufficiently fine toner having a large circularity and a sharp particle size distribution can be obtained relatively easily.

  The frequency (frequency of the piezoelectric pulse) of the piezoelectric element 22 is not particularly limited, but is preferably 1 kHz to 500 MHz, and more preferably 5 kHz to 200 MHz. When the vibration frequency of the piezoelectric element 22 is less than the lower limit value, toner productivity decreases. On the other hand, when the vibration frequency of the piezoelectric element 22 exceeds the upper limit, the discharge of the granular dispersion liquid 6 cannot follow, and there is a possibility that the dispersion of the size of one drop of the dispersion liquid 6 becomes large.

The toner manufacturing apparatus 1 having the illustrated configuration has a plurality of head portions 2. Then, a granular dispersion 6 is discharged from each of these head units 2 to the solidifying unit 3.
Each head unit 2 may discharge the dispersion 6 almost simultaneously, but it is preferable that at least two adjacent head units are controlled so that the discharge timing of the dispersion 6 is different. . Thereby, before the granular dispersion liquid 6 discharged from the adjacent head part 2 is solidified (before becoming the aggregate 9), the granular dispersion liquid (droplets) collide with each other, and these are aggregated. It can prevent more effectively.

  Further, as shown in FIG. 2, the toner manufacturing apparatus 1 includes a gas flow supply unit 10, and the gas supplied from the gas flow supply unit 10 passes through the duct 101 to the head unit 2 -head. From each gas injection port 7 provided between the parts 2, it becomes the structure injected by a substantially uniform pressure. Thereby, the dispersion liquid 6 can be conveyed and an aggregate can be obtained (solidified), maintaining the space | interval of the granular dispersion liquid 6 discharged from the discharge part 23 intermittently. As a result, collision and aggregation of discharged granular dispersion liquids 6 (droplets) are more effectively prevented.

In addition, by injecting the gas supplied from the gas flow supply means 10 from the gas injection port 7, it is possible to form a gas flow that flows in substantially one direction (downward in the figure) in the solidifying unit 3. When such a gas flow is formed, the granular dispersion 6 (aggregate 9) in the solidification unit 3 can be conveyed more efficiently.
In addition, an air current curtain is formed between particles ejected from each head unit 2 by ejecting gas from the gas ejection port 7, for example, a collision between particles ejected from adjacent head units, Aggregation can be prevented more effectively.

A heat exchanger 11 is attached to the gas flow supply means 10. Thereby, the temperature of the gas injected from the gas injection port 7 can be set to a preferable value, and the granular dispersion 6 discharged to the solidifying unit 3 can be solidified efficiently.
Further, when such a gas flow supply means 10 is provided, it is possible to easily control the solidification speed and the like of the dispersion 6 discharged from the discharge unit 23 by adjusting the supply amount of the gas flow. .

  The temperature of the gas injected from the gas injection port 7 varies depending on the composition of the dispersoid 61 and the aqueous dispersion medium 62 contained in the dispersion 6, but is usually preferably 0 to 70 ° C., and 15 to 60. More preferably, it is ° C. When the temperature of the gas injected from the gas injection port 7 is in such a range, the shape and uniformity of the shape of the obtained aggregate 9 are sufficiently high and contained in the dispersion 6. The aqueous dispersion medium 62 can be efficiently removed, and as a result, the toner productivity can be made particularly excellent.

  Moreover, the humidity of the gas injected from the gas injection port 7 is preferably 50% RH or less, and more preferably 30% RH or less, for example. When the humidity of the gas injected from the gas injection port 7 is 50% RH or less, the aqueous dispersion medium 62 contained in the dispersion 6 can be efficiently removed in the solidification unit 3 described later, and the aggregate 9 The productivity of (toner) is further improved.

  The droplet-like dispersion 6 discharged from the head unit 2 is solidified while being transported through the solidification unit 3, thereby forming an aggregate 9 in which a plurality of fine particles derived from the dispersoid 61 are aggregated. That is, as the aqueous dispersion medium 62 in the discharged dispersion liquid 6 is removed, the dispersoid 61 contained in the dispersion liquid 6 aggregates, and as a result, an aggregate 9 is obtained. In addition, when the above-mentioned solvent is contained in the dispersoid 61, the said solvent is also normally removed in the solidification part 3. FIG.

The particle size of the dispersoid 61 contained in the dispersion 6 is usually sufficiently smaller than the obtained aggregate 9 (the granular dispersion 6 to be discharged). Therefore, the obtained aggregate 9 has a sufficiently large circularity.
Further, since the aqueous dispersion medium 61 is removed in the solidifying unit 3, the obtained aggregate 9 is usually smaller than the droplet-like dispersion 6 discharged from the discharge unit 23. For this reason, even when the area (opening area) of the discharge part 23 is relatively large, the size of the obtained aggregate 9 can be made relatively small. Therefore, in the present invention, even if the head portion 2 is not obtained by performing special precision processing (even if it can be manufactured relatively easily), the sufficiently fine aggregate 9 and toner Particles can be obtained.
In addition, as described above, in the present embodiment, it is not necessary to extremely reduce the area of the discharge unit 23, so that the particle size distribution of the dispersion 6 discharged from each head unit 2 can be sufficiently sharpened relatively easily. Can be. As a result, the toner finally obtained also has a small variation in particle size among the particles, that is, a sharp particle size distribution.

Aggregates 9 obtained by solidifying the granular dispersion 6 are collected in the collection unit 5.
The treatment time of the dispersion medium removing step as described above (the time from when the dispersion liquid 6 is jetted into droplets until the aggregate 9 is recovered in the recovery unit 5) is preferably 5 to 120 seconds, The time is more preferably 5 to 60 seconds, and further preferably 5 to 20 seconds. When the processing time of the dispersion medium removal step is a value within such a range, it is possible to sufficiently increase the productivity as a toner while making the obtained aggregate 9 sufficiently strong.

The dispersion medium removing step may be any step as long as the water content is lowered to such an extent that the obtained aggregate 9 has an appropriate stability, and the step of transporting the discharged dispersion liquid 6 as described above through the solidification unit 3 ( (Conveying step) may be configured only, and in addition to the conveying step, a step of removing the aqueous dispersion medium by aeration, vacuum degassing (vacuum degassing), heating, or the like may be included. Good.
In the dispersion medium removing step, the water content (water content) of the obtained aggregate 9 is preferably 5.0% or less, more preferably 0.01 to 4 wt%, and 0.02 to 2 wt%. More preferably, it is made to. Thereby, the finally obtained toner can have excellent charging characteristics, durability, and ease of handling.

Further, when the dispersion medium removing step includes a conveying step and an aeration step, the water content (moisture content) of the aggregate 9 obtained in the conveying step is preferably 15 wt% or less, and preferably It is more preferably 1 to 12 wt%, and further preferably 0.2 to 10 wt%. When the water content in the aggregate 9 obtained in the transporting process is too large, there is a possibility that the water content in the final toner particles becomes relatively large and the charging becomes unstable.
Aggregates 9 obtained as described above may be used as toner particles (toner base particles) as they are, or, if necessary, for aggregate 9 obtained as described above. In addition, a joining process for melting and joining a plurality of fine particles constituting the aggregate 9 may be performed (joining step).

  When performing the bonding process, the processing temperature in the bonding process (bonding process) is equal to or higher than the glass transition point of the resin material constituting the resin fine particles (resin material constituting the dispersoid 61). Thereby, a plurality of fine particles constituting the aggregate 9 can be more reliably bonded to each other, and the mechanical strength (mechanical stability) of the finally obtained toner particles is particularly excellent. it can. Further, the roundness (trueness) of the toner particles finally obtained by performing the bonding process (bonding process) at a temperature equal to or higher than the glass transition point of the resin material constituting the resin fine particles (resin material constituting the dispersoid 61). Sphericity) can be easily and reliably made relatively large.

  The treatment temperature in the joining step (joining treatment) is preferably higher than the treatment temperature in the dispersion medium removing step. Thereby, the fusion | melting joining of microparticles | fine-particles can be advanced more smoothly. Further, even when a relatively large amount of the aqueous dispersion medium 62 or the like is contained in the aggregate 9, the content (residual amount) of the aqueous dispersion medium or the like can be effectively reduced. It is possible to prevent substantially any aqueous dispersion medium or the like from remaining in typical toner particles.

More specifically, when the treatment temperature in the dispersion medium removing step is T ₁ [° C.] and the treatment temperature in the joining step is T ₂ [° C.], the relationship of 0 ≦ T ₂ −T ₁ ≦ 200 is satisfied. Is preferable, 10 ≦ T ₂ −T ₁ ≦ 200 is more preferable, 20 ≦ T ₂ −T ₁ ≦ 100 is more preferable, and 25 ≦ T ₂ −T ₁ ≦ 80. It is most preferable to satisfy this relationship. By satisfying such a relationship, the uniformity and stability of the shape of the obtained toner particles are sufficiently high while sufficiently preventing deterioration and modification of the constituent components, and further, the circularity of the toner particles is increased. It can be relatively large.

Further, when the treatment temperature in the joining step (joining treatment) is T ₂ [° C.] and the melting point of the resin material constituting the resin fine particles (the resin material constituting the dispersoid 61) is Tm [° C.], −100 ≦ It is preferable to satisfy the relationship of T ₂ −Tm ≦ 110, more preferably satisfy the relationship of −80 ≦ T ₂ −Tm ≦ 80, and satisfy the relationship of −50 ≦ T ₂ −Tm ≦ 70. More preferably, it is most preferable that the relationship of −40 ≦ T ₂ −Tm ≦ 30 is satisfied. By satisfying such a relationship, the uniformity and stability of the shape of the obtained toner particles are sufficiently high while sufficiently preventing deterioration and modification of the constituent components, and further, the circularity of the toner particles is increased. It can be relatively large. If the resin material constituting the resin fine particles (resin material constituting the dispersoid 61) is composed of a plurality of types of resin materials (resin components), the weight-based weighting of each of these components is designated as Tm. A value obtained as an average value can be adopted.

In particular, the treatment temperature in the joining step (joining treatment) is not less than the glass transition point of the resin material constituting the resin fine particles (resin material constituting the dispersoid 61) and the resin material constituting the resin fine particles. The temperature is preferably equal to or lower than the melting point of (the resin material constituting dispersoid 61). Thereby, the effects as described above can be made more remarkable.
Moreover, the specific value of the processing temperature in a joining process (joining process) is although it does not specifically limit, Usually, when the processing time of a joining process (joining process) is a value within the range which is mentioned later, 50-200 normally. It is preferable that it is ° C, and it is more preferable that it is 60-150 ° C. By satisfying such a relationship, the uniformity and stability of the shape of the obtained toner particles are sufficiently high while sufficiently preventing deterioration and modification of the constituent components, and further, the circularity of the toner particles is increased. It can be relatively large.

  The processing time of the joining process (joining process) as described above is not particularly limited, but is 0.01 to 10 seconds when the processing temperature of the joining process (joining process) is a value within the range as described above. Is preferable, 0.05 to 10 seconds is more preferable, and 0.1 to 5 seconds is further preferable. When the processing time of the joining step is within such a range, the circularity of the toner particles can be made sufficiently large while sufficiently preventing deterioration or modification of the constituent material of the toner.

  The bonding process (bonding process) may be performed by any method, and for example, heating with a heater, heating with hot air, induction heating such as high-frequency heating or microwave heating can be used. Among these, induction heating is preferable because accurate heating temperature can be easily controlled. In particular, the heating method used for the bonding treatment is preferably microwave heating, that is, the aggregate 9 is irradiated with microwaves to be heated. Thereby, since the whole aggregate 9 can be heated uniformly, the several fine particle which comprises the aggregate 9 can be joined more reliably, and the mechanical strength ( The mechanical stability) can be made particularly excellent. Further, when the aqueous dispersion medium 62 is water or the like, the aqueous dispersion medium 62 remaining in the aggregate 9 can be selectively heated, thereby sufficiently preventing deterioration and modification of the resin in the aggregate 9. Meanwhile, a plurality of fine particles constituting the aggregate 9 can be joined. In this case, heating by microwaves may be performed alone or in combination with other heating means such as a heater or hot air.

As described above, according to the present invention, the generation of hollow particles and irregularly shaped particles can be reliably prevented, and a toner (resin fine particles) having a uniform shape and a narrow particle size distribution can be produced. . As a result, the obtained toner has a uniform charge between the particles, and the toner thin layer formed on the developing roller is leveled and densified when the toner is used for printing. Become. As a result, defects such as fog are hardly generated and a sharper image can be formed. Further, since the shape and particle size of the toner particles are uniform, the bulk density of the whole toner (aggregation of toner particles) can be increased. As a result, it is advantageous for increasing the amount of toner filled in the cartridge of the same volume and for reducing the size of the cartridge.
The toner obtained as described above may be subjected to various processes such as aeration, classification, and external addition as necessary.

For the classification treatment, for example, a sieve, an airflow classifier or the like can be used.
Examples of the external additive used for the external addition treatment include metal oxides such as silica, aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, titania, zinc oxide, alumina, and magnetite. Fine particles composed of inorganic materials such as nitrides such as silicon nitride, carbides such as silicon carbide, calcium sulfate, calcium carbonate, aliphatic metal salts, acrylic resins, fluororesins, polystyrene resins, polyester resins, aliphatic metal salts Fine particles composed of organic materials such as these, and fine particles composed of a composite of these.

As the external additive, the surface of the fine particles as described above is subjected to a surface treatment with HMDS, a silane coupling agent, a titanate coupling agent, a fluorine-containing silane coupling agent, silicone oil or the like. It may be used.
The toner of the present invention produced as described above has a uniform shape and a sharp particle size distribution (small width). In particular, in the present invention, toner particles having a shape close to a true sphere can be obtained.

Specifically, the toner (toner particles) preferably has an average circularity R represented by the following formula (I) of 0.95 or more, more preferably 0.96 or more, and 0.97. More preferably, it is 0.98 or more. When the average circularity R is 0.95 or more, the toner transfer efficiency is further improved.
R = L ₀ / L ₁ (I)
(Where, L ₁ [μm] is the circumference of the projected image of the toner particles to be measured, and L ₀ [μm] is a perfect circle having an area equal to the area of the projected image of the toner particles to be measured (completely (Represents the perimeter of a geometric circle)
The toner preferably has a standard deviation of average circularity between particles of 0.02 or less, more preferably 0.015 or less, and further preferably 0.01 or less. When the standard deviation of the average circularity between the particles is 0.02 or less, variations such as charging characteristics and fixing characteristics are particularly reduced, and the reliability of the toner as a whole is further improved.

  The volume-based average particle diameter of the toner obtained as described above is preferably 2 to 20 μm, and more preferably 4 to 10 μm. When the average particle size of the toner is less than the lower limit, it becomes difficult to uniformly charge, and the adhesion force to the surface of the electrostatic latent image carrier (for example, a photoreceptor) increases. As a result, There may be an increase in the residual toner. On the other hand, when the average particle size of the toner exceeds the upper limit, the reproducibility of the contour portion of an image formed using the toner, particularly a character image or a light pattern, is deteriorated.

  Further, the toner preferably has a standard deviation of the particle size between particles of 1.5 μm or less, more preferably 1.3 μm or less, and even more preferably 1.0 μm or less. When the standard deviation of the particle diameter between the particles is 1.5 μm or less, variations in charging characteristics, fixing characteristics and the like are particularly small, and the reliability of the toner as a whole is further improved.

The toner has a bulk density of preferably at 0.34 g / cm ³ or more, more preferably from 0.35~0.50g / cm ^3. This improves toner characteristics such as durability and transfer efficiency. Further, it is possible to increase the amount of toner filled in the cartridge of the same volume, and to reduce the size of the cartridge.
The water content (water content) of the toner particles is not particularly limited, but is preferably 4.0 wt% or less, more preferably 0.01 to 3.0 wt%, and 0.01 to 1. More preferably, it is 0 wt%. When the water content in the toner particles is too high, there is a possibility that charging becomes unstable. If the water content in the toner particles is extremely reduced, the toner constituent materials are likely to be deteriorated or modified, and therefore it is not necessary to reduce the water content more than necessary.

Next, a second embodiment of the present invention will be described. Hereinafter, the present embodiment will be described with a focus on differences from the above-described embodiments, and description of similar matters will be omitted.
This embodiment has the same configuration as that of the first embodiment except that the configuration of the head portion of the toner manufacturing apparatus used for manufacturing the aggregate (toner particles) is different.
FIG. 3 is a diagram schematically showing a structure in the vicinity of the head portion of the toner manufacturing apparatus of the present embodiment.

As shown in FIG. 3, in the toner manufacturing apparatus of the present embodiment, an acoustic lens (concave lens) 25 is installed in the head unit 2. By installing such an acoustic lens 25, for example, the pressure pulse (vibration energy) generated by the piezoelectric element 22 can be converged by the pressure pulse converging unit 26 in the vicinity of the ejection unit 23. As a result, vibration energy generated by the piezoelectric element 22 can be efficiently used as energy for discharging the dispersion liquid 6. Therefore, even if the dispersion liquid 6 stored in the dispersion liquid storage unit 21 has a relatively high viscosity, it can be reliably discharged from the discharge unit 23. In addition, even if the dispersion 6 stored in the dispersion storage unit 21 has a relatively large cohesive force (surface tension), it can be discharged as fine droplets. The particle size of the aggregate 9 and finally obtained toner particles can be controlled to a relatively small value.
As described above, in this embodiment, even when a material having a higher viscosity or a material having a large cohesive force is used as the dispersion liquid 6, the aggregate 9 can be controlled to have a desired shape and size. Therefore, the range of material selection is particularly wide, and a toner having desired characteristics can be obtained more easily.

  In the present embodiment, since the dispersion liquid 6 is ejected by the converged pressure pulse, the size of the dispersion liquid 6 to be ejected is relatively large even when the area (opening area) of the ejection portion 23 is relatively large. Can be small. That is, even when it is desired to relatively reduce the particle size of the finally obtained toner particles, the area of the discharge portion 23 can be increased. Thereby, even if the dispersion liquid 6 has a relatively high viscosity, the occurrence of clogging or the like in the discharge unit 23 can be more effectively prevented.

As mentioned above, although this invention was demonstrated based on suitable embodiment, this invention is not limited to this.
For example, each unit constituting the toner manufacturing apparatus can be replaced with an arbitrary one that exhibits the same function, or another configuration can be added. For example, in the above-described embodiment, the configuration in which the granular dispersion liquid is discharged downward in the vertical direction has been described. However, the discharge direction of the dispersion liquid may be any direction such as vertically upward or in the horizontal direction. Moreover, as shown in FIG. 7, the thing of the structure from which the discharge direction of the dispersion liquid 6 and the injection direction of the gas injected from the gas injection port 7 become substantially perpendicular | vertical may be sufficient. In this case, the traveling direction of the discharged granular dispersion liquid 6 changes depending on the gas flow, and is transported substantially at right angles to the discharge direction from the discharge unit 23.

Moreover, although the said 2nd Embodiment demonstrated the structure which used the concave lens as an acoustic lens, an acoustic lens is not limited to this. For example, a Fresnel lens, an electronic scanning lens, or the like may be used as the acoustic lens.
Furthermore, in the said 2nd Embodiment, although the structure which interposed only the dispersion liquid 6 between the acoustic lens 25 and the discharge part 23 was demonstrated, as shown to FIGS. 4-6, for example, the acoustic lens 25 is shown. A diaphragm member 13 having a converging shape may be disposed between the nozzle and the discharge unit 23 toward the discharge unit 23. Thereby, convergence of the pressure pulse (vibration energy) generated by the piezoelectric element 22 can be assisted, and the pressure pulse generated by the piezoelectric element 22 can be used more efficiently.

  In the above-described embodiment, the dispersion liquid is intermittently ejected from the head portion by the piezoelectric pulse. However, other methods can be used as a dispersion liquid ejection method (injection method). For example, as a method for discharging (injecting) the dispersion liquid, a method such as a spray drying method or a so-called bubble jet (“Bubble Jet” is a registered trademark) method is used. A method of injecting a dispersion liquid in the form of droplets (as fine particles) using a nozzle that draws the thin layer flow into a thin laminar flow and injects the thin laminar flow away from the smooth surface as fine particles (Japanese Patent Application 2002-2002) The method as described in the specification of US Pat. No. 3,218,89) may be used. The spray drying method is a method of obtaining liquid droplets by spraying (spraying) a liquid (dispersion) using a high-pressure gas. Moreover, as a method to which a so-called bubble jet (“bubble jet” is a registered trademark) method is applied, a method described in the specification of Japanese Patent Application No. 2002-169348 can be cited. That is, as a method for ejecting (injecting) the dispersion liquid, a “method for intermittently ejecting the dispersion liquid from the head portion by a change in gas volume” can be applied.

In the above-described embodiment, the method for producing toner particles as resin fine particles has been described. However, the resin fine particles to which the present invention is applied are not limited to toner particles, and may be any type.
For example, when a powder coating is manufactured using the method for manufacturing resin fine particles of the present invention, a coating film coated with the obtained powder coating has extremely excellent smoothness and has a coating film defect. Very little.

[1] Production of toner (Example 1)
First, an epoxy resin (glass transition point Tg: 90 ° C., melting point Tm: 115 ° C.): 100 parts by weight as a binder resin, phthalocyanine pigment (manufactured by Dainichi Seika Co., Ltd., phthalocyanine blue) as a colorant: 5 parts by weight, as a solvent Tetrahydrofuran (manufactured by Wako Pure Chemical Industries): 300 parts by weight were prepared.

These components were mixed and dispersed with a ball mill for 10 hours to prepare a binder resin solution (resin solution).
On the other hand, an aqueous solution (aqueous solution) prepared by dissolving 10 parts by weight of sodium polyacrylate as a dispersant (manufactured by Wako Pure Chemical Industries, average polymerization degree n = 2700-7500) in 590 parts by weight of ion-exchanged water was prepared.

  Next, 600 parts by weight of this aqueous solution is placed in a 3 liter round bottom stainless steel container, and a binder resin solution: 409 wt. The portion was gradually added dropwise over 10 minutes. At this time, the liquid temperature was kept at 70 ° C. The emulsion was further stirred for 10 minutes while maintaining the liquid temperature at 70 ° C. after the completion of the dropwise addition of the binder resin solution.

Next, under conditions of temperature: 45 ° C. and atmospheric pressure: 10 to 20 kPa, tetrahydrofuran in the emulsion (dispersoid) is removed, then cooled to room temperature, and further ion-exchanged water is added to form a solid. A binder resin suspension (dispersion) in which fine particles were dispersed was obtained.
Thereafter, the obtained binder resin suspension (dispersion) was degassed. The deaeration treatment was performed by placing the binder resin suspension (dispersion) in a stirred state in an atmosphere of 14 kPa for 10 minutes. The ambient temperature during the deaeration treatment was 25 ° C. The solid content (dispersoid) concentration in the binder resin suspension (dispersion) thus obtained was 10 wt%. The viscosity of the binder resin suspension (dispersion) at 25 ° C. was 2 mPa · s. Moreover, the average particle diameter Dm of the dispersoid constituting the binder resin suspension was 0.4 μm. The average particle size of the dispersoid was measured using a laser diffraction / scattering particle size distribution analyzer (LA-920, manufactured by Horiba, Ltd.).

  The degassed dispersion (binder resin suspension) was put into a dispersion supply section of a toner production apparatus as shown in FIGS. While stirring the dispersion liquid in the dispersion liquid supply part with the stirring means, the liquid was supplied to the dispersion liquid storage part of the head part by the metering pump, and was discharged from the discharge part to the solidification part. The discharge part had a circular shape with a diameter of 26 μm. Further, as the head portion, a head portion that has been subjected to a hydrophobic treatment with a fluororesin (polytetrafluoroethylene) coat in the vicinity of the discharge portion is used.

Dispersion liquid is discharged at a dispersion temperature of 25 ° C. in the head part, the frequency of the piezoelectric body is 10 kHz, the initial speed of the dispersion liquid discharged from the discharge part is 4 m / second, and one drop of the dispersion liquid discharged from the head part. The discharge amount was adjusted to 3 pl (particle size Dd: 18 μm, weight: about 3 ng). Further, the dispersion liquid was discharged so that the discharge timing of the dispersion liquid was shifted in at least adjacent head parts among the plurality of head parts.
Further, when the dispersion liquid is discharged, air at a temperature of 50 ° C., humidity of 27% RH, and a flow velocity of 4 m / second is jetted vertically downward from the gas injection port, and the pressure in the housing (atmospheric pressure) is large. The pressure was adjusted to be atmospheric pressure. The temperature (atmosphere temperature) in the housing was adjusted to 50 ° C. The length of the solidified part (length in the transport direction) was 2 m.

  In the solidification part, the aqueous dispersion medium was removed from the discharged dispersion to form aggregates of dispersoids (fine particles), and the formed aggregates were recovered in the recovery part (dispersion medium removal step). Further, the processing time (time required for passing through the solidified portion) of the dispersion medium removing step for each particle (droplet and aggregate formed from the droplet) was 12 seconds. The water content of the obtained aggregate was 4.0 wt% or less.

Thereafter, the agglomerates obtained were aerated for 3 hours while being heated to 50 ° C. to obtain toner particles.
The resulting toner particles had a water content of 0.3 to 0.5 wt%, an average circularity R of 0.982, and a circularity standard deviation of 0.012. The volume-based average particle diameter Dt was 6.5 μm. The volume standard particle size standard deviation was 0.7 μm. The water content was measured by the Karl Fischer method. In addition, the circularity was measured in a water dispersion system using a flow type particle image analyzer (manufactured by Toa Medical Electronics Co., Ltd., FPIA-2000).

(Examples 2 and 3)
A toner was manufactured in the same manner as in Example 1 except that the processing temperature and processing time in each step were changed as shown in Table 1.
Example 4
A toner was manufactured in the same manner as in Example 1 except that an epoxy resin (glass transition point Tg: 60 ° C., melting point Tm: 105 ° C.) was used as the binder resin.

(Example 5)
A toner was manufactured in the same manner as in Example 1 except that an epoxy resin (glass transition point Tg: 75 ° C., melting point Tm: 110 ° C.) was used as the binder resin.
(Example 6)
A toner was manufactured in the same manner as in Example 1 except that a polyester resin (glass transition point Tg: 60 ° C., melting point Tm: 155 ° C.) was used as the binder resin.

(Comparative Example 1)
Except that the temperature of the gas (air) injected from the gas injection port at the time of discharging the dispersion liquid is 110 ° C., the temperature inside the housing (atmosphere temperature) is 110 ° C., and aeration is performed at 110 ° C. for 1 minute. A toner was produced in the same manner as in Example 1.
(Comparative Example 2)
A toner was manufactured in the same manner as in Example 2 except that an epoxy resin (glass transition point Tg: 60 ° C., melting point Tm: 105 ° C.) was used as the binder resin.

(Comparative Example 3)
An epoxy resin (glass transition point Tg: 60 ° C., melting point Tm: 105 ° C.) is used as the binder resin, and the temperature of the gas (air) injected from the gas injection port during discharge of the dispersion is 40 ° C. in the housing. The toner was manufactured in the same manner as in Example 1 except that the temperature (atmosphere temperature) was 40 ° C. and aeration was performed at 40 ° C. for 1 minute. In addition, the water content of the aggregate obtained in the transporting process was 20% or more.

The toner particles obtained in Examples 1 to 6 were observed for their surface shapes using a scanning electron microscope (SEM). In the toner particles of Examples 1 to 5, it was confirmed that no relatively large irregularities were observed on the surface, and the toner particles were substantially spherical. On the other hand, it was confirmed that the toner particles of each comparative example had relatively large irregularities, and the shape variation between the particles was large.
Table 1 shows the toner production conditions for the above Examples and Comparative Examples.

[2] Evaluation Each toner obtained as described above was evaluated for the abundance ratio, durability, and transfer efficiency of the hollow particles.
[2.1] Abundance ratio of hollow particles For each toner obtained in each of the above Examples and Comparative Examples, the internal structure of each toner particle was observed using a transmission electron microscope (TEM). The abundance ratio of the hollow particles was evaluated according to the following four criteria.

A: The presence of hollow particles is not recognized at all.
A: The presence of hollow particles is slightly observed, but the abundance ratio is less than 1%.
Δ: The abundance ratio of hollow particles is 1% or more and less than 3%.
X: The abundance ratio of the hollow particles is 3% or more.
Examples of electron micrographs of the toner particles obtained by the methods of Example 1 and Comparative Example 1 are shown in FIGS. 8 and 9, respectively.
Further, as an indicator of the presence of hollow particles, the bulk density was measured for each toner obtained in each of the above Examples and each of the above Comparative Examples using a bulk specific gravity measuring instrument (JIS-K5101, manufactured by Tsutsui Rikagaku Co., Ltd.). .

[2.2] Durability The toner obtained in each of the above Examples and Comparative Examples was set in a developing machine of a color laser printer (manufactured by Seiko Epson Corporation: LP-2000C). Thereafter, the developing machine was continuously rotated so as not to print. After 12 hours, the developing machine was taken out, the uniformity of the toner thin layer on the developing roller was visually confirmed, and evaluated according to the following four criteria.
A: No disturbance is observed in the thin layer.
○: Disturbance is hardly observed in the thin layer.
Δ: Some disturbance is observed in the thin layer.
X: Streaky disturbance is clearly observed in the thin layer.

[2.3] Transfer Efficiency The transfer efficiency of each toner obtained as described above was evaluated.
Transfer efficiency was evaluated as follows using a color laser printer (manufactured by Seiko Epson Corporation, LP-2000C).
The toner on the photoconductor immediately after the development process to the photoconductor (before transfer) and the toner on the photoconductor after transfer (after printing) were collected using different tapes, and their weights were measured. When the toner weight on the photoconductor before transfer is W _b [g] and the toner weight on the photoconductor after transfer is W _a [g], it is obtained as (W _b −W _a ) × 100 / W _b. The value was defined as transfer efficiency.

[2.4] Good Fixing Area First, a laser printer equipped with a fixing device (manufactured by Seiko Epson Corporation, LP-3000C) was prepared. In this fixing device, the time Δt required for the toner to pass through the nip portion was set to 0.05 seconds.
Next, an unfixed image sample was collected using the above laser printer, and the following test was performed with the fixing device of the laser printer. The solid amount of the sample to be collected was adjusted to an adhesion amount of 0.40 to 0.50 mg / cm ² .

In the state where the surface temperature of the fixing roller of the fixing device constituting the laser printer is set to a predetermined temperature, the paper on which the unfixed toner image is transferred (Seiko Epson, high-quality plain paper) is introduced into the fixing device. As a result, the toner image was fixed on the paper, and the presence or absence of offset after fixing was visually confirmed.
Similarly, the set temperature of the surface of the fixing roller is sequentially changed within a range of 100 to 250 ° C., and the presence or absence of occurrence of an offset at each temperature is confirmed. It was determined as “range” and evaluated according to the following four-stage criteria. Further, the temperature at which fixing was started was measured.

(Double-circle): The width | variety of a favorable fixing area is 60 degreeC or more.
◯: The width of the fixing good region is 45 ° C. or more and less than 60 ° C.
(Triangle | delta): The width | variety of a favorable fixing area is 30 degreeC or more and less than 45 degreeC.
X: The width of the good fixing region is less than 30 ° C.
These results are shown in Table 2 together with the average circularity R, circularity standard deviation, volume-based average particle diameter Dt, and particle diameter standard deviation of the toner particles.

As is apparent from Table 2, the toners of the present invention (Examples 1 to 6) all had a large degree of circularity and a small width of the particle size distribution. Further, the variation in shape (standard deviation of circularity) was small, and irregularly shaped toner particles such as hollow particles were not substantially contained.
On the other hand, the toner of each comparative example has a particularly small circularity, and a large number of toner particles having relatively large convex portions were observed. This is considered to be due to the following reasons.
That is, in Examples 1 to 6, since the raw material to be discharged or sprayed is a dispersion (suspension), it is selectively selected at the portion of the aqueous dispersion medium having a microscopically low viscosity at the time of discharging or spraying. Cut and discharged. Further, since the aqueous aqueous dispersion medium has an appropriate surface tension, the discharge liquid becomes spherical after discharge quickly. Furthermore, in Examples 1 to 6, since the rapid removal of the aqueous dispersion medium (particularly, the rapid removal of the aqueous dispersion medium from the vicinity of the center of the droplet-like dispersion (sudden boiling)) is reliably prevented, Aggregates (toner particles) have a high degree of circularity and a small variation in shape, and are substantially free of irregularly shaped toner particles such as hollow particles, or even if they are included, the abundance ratio is extremely low. .

  On the other hand, in Comparative Examples 1 and 2, since the dispersion liquid is rapidly heated immediately after being discharged in the form of droplets, the aqueous dispersion medium is removed from the dispersion liquid discharged in the form of droplets. Since the agglomeration of the dispersoids does not proceed uniformly, the obtained toner particles have a large number of relatively large irregularities in the vicinity of the surface, and the shape and size varies greatly among the particles. Further, since the removal of the aqueous dispersion medium proceeds rapidly, the existence ratio of irregularly shaped toner particles such as hollow particles becomes high. Further, Comparative Example 3 has a relatively uniform shape before aeration, but the moisture content is high, so the durability is reduced and the aeration is crushed. That is, in Comparative Example 3, it was not possible to reduce the water content and achieve both shape uniformity.

From the above, it is considered that toner particles having relatively large convex portions were generated in the comparative example.
In Examples 1 to 5, the time required for removing the aqueous dispersion medium was short, and the toner could be produced efficiently. This is probably because a binder resin having a relatively low water absorption was used.
Further, as apparent from Table 2, the toner of the present invention was excellent in transfer efficiency. On the other hand, the toner of each comparative example was inferior in transfer efficiency. This is because the toner of the comparative example has a large variation in shape and size between each particle, and many irregular shaped toner particles such as hollow particles are included, so that the variation in characteristics between each particle is large. The toner of the present invention substantially does not contain irregularly shaped toner particles such as hollow particles (or the existence ratio is extremely low even if it is contained), and the shape, size between the toner particles as described above, This is considered to be due to the fact that the variation in characteristics is sufficiently small. Further, the toner of the present invention had excellent durability, while the toner of the comparative example was inferior in durability.

Such transfer characteristics and durability results also contribute to the fact that the toner of the present invention does not substantially contain irregularly shaped toner particles such as hollow particles, or the existence ratio is extremely low even if included. It is thought that.
Further, as apparent from Table 2, the toner of the present invention was excellent in low-temperature fixability. Further, the toners of Examples 1 to 5 were particularly excellent in low-temperature fixability. This is considered to be because the thermosetting resin is not unintentionally heat-cured in the dispersion medium removing step and is heat-cured at the time of fixing.
On the other hand, the toner of each comparative example was inferior in fixability. This is presumably because the toner of the comparative example was dried at a high temperature during the aqueous dispersion medium removal treatment, and the resin constituting the toner was modified and deteriorated.

[3] Production of powder paint (Example 7)
Resin fine particles were produced in the same manner as in Example 1 except that a disk type spray dryer (DCTRS-3N type, manufactured by Sakamoto Giken Co., Ltd.) was used for spraying the dispersion, and this was used as a powder coating material.
At this time, the dispersion was sprayed by injecting the dispersion with compressed air having a temperature of 40 ° C. and a pressure of 0.65 MPa at an initial speed of 4 m / sec. Further, the dispersion was sprayed at 20 mL / min, and the average spray amount for one drop of the dispersion sprayed from the nozzle was 3 pl (particle diameter D ′: 18 μm).

(Example 8)
A powder coating material was produced in the same manner as in Example 7 except that an epoxy resin (glass transition point Tg: 60 ° C., melting point Tm: 105 ° C.) was used as the binder resin.
(Comparative Example 4)
A powder coating material was produced in the same manner as in Example 7, except that the compressed air used for spraying the dispersion was set to a temperature of 150 ° C., a pressure of 0.55 MPa, and the temperature in the solidified portion was set to 150 ° C.

[4] Evaluation For each powder paint obtained as described above, the abundance ratio of the hollow particles was evaluated in the same manner as in [2.1] described above.
As apparent from Table 2, the powder coating material of the present invention (Examples 7 and 8) did not substantially contain irregular-shaped coating particles such as hollow particles.

On the other hand, in the powder coating material of Comparative Example 4, many coating particles having relatively large convex portions were recognized.
Further, the powder coating materials of Examples 7 and 8 have a larger bulk density than the powder coating material of Comparative Example 4, so that it can be seen that there are fewer hollow particles than the powder coating material of Comparative Example 4.
About each such powder coating material, it applied to a base material, and when the external appearance of the obtained coating film was visually observed, the coating film using the powder coating material of Examples 7 and 8 was extremely excellent in smoothness. In addition, no coating film defects were observed. On the other hand, the coating film using the powder coating material of Comparative Example 4 was inferior in smoothness as compared with Examples 7 and 8, and coating film defects such as pinholes were confirmed.

In addition, the said base material used what applied the melamine hardening polyester resin system intermediate coating to the mild steel plate (Nippon Parkerizing Co., Ltd. bonderite # 3030) which electrodeposited the epoxy resin system cationic electrodeposition coating.
In addition, each powder coating is applied in two portions so that the dried coating film is 20 μm in an environment of a temperature of 25 ° C. and a relative humidity of 65 to 70%. Baking was performed for a minute to obtain a coating film. The air pressure of the spray gun at the time of painting was 5 kg / cm, the flow rate of the paint was 400 m / min, and the distance between the substrate and the spray gun was 40 cm.

1 is a longitudinal sectional view schematically showing a first embodiment of a toner manufacturing apparatus used for manufacturing a toner of the present invention. FIG. 2 is an enlarged cross-sectional view of the vicinity of a head portion of the toner manufacturing apparatus shown in FIG. 1. FIG. 6 is a diagram schematically illustrating a structure near a head portion of a toner manufacturing apparatus according to a second embodiment. It is a figure which shows typically the structure of the head part vicinity of the toner manufacturing apparatus of other embodiment. It is a figure which shows typically the structure of the head part vicinity of the toner manufacturing apparatus of other embodiment. It is a figure which shows typically the structure of the head part vicinity of the toner manufacturing apparatus of other embodiment. It is a figure which shows typically the structure of the head part vicinity of the toner manufacturing apparatus of other embodiment. 2 is an example of an electron micrograph of the toner of the present invention. 3 is an example of an electron micrograph of a toner of a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Toner manufacturing apparatus 2 ... Head part 21 ... Dispersion liquid storage part 22 ... Piezoelectric element 221 ... Lower electrode 222 ... Piezoelectric body 223 ... Upper electrode 23 ... Discharge part 24 ... Diaphragm 25 ... ... Acoustic lens 26 ... Pressure pulse converging part 3 ... Solidifying part 31 ... Housing 311 ... Reduced diameter part 4 ... Dispersing liquid supply part 41 ... Agitating means 5 ... Recovery part 6 ... Dispersing liquid 61 ... Dispersoid 62 ... Aqueous dispersion medium 7 ... Gas injection port 8 ... Voltage application means 9 ... Agglomerate 10 ... Gas flow supply means 101 ... Duct 11 ... Heat exchanger 12 ... Pressure adjustment means 121 ... … Connecting pipe 122 …… Expanded diameter part 123 …… Filter 13 …… Drawing member

Claims (15)

A method for producing resin fine particles by discharging a dispersion in which a dispersoid mainly composed of a resin material is finely dispersed in an aqueous dispersion medium into droplets,
Removing the aqueous dispersion medium from the droplet-like dispersion by heating, and aggregating the plurality of dispersoids contained in the droplet-like dispersion to obtain an aggregate;
The heating temperature is 50 to 100 ° C., and
A resin fine particle production method, wherein a resin having a glass transition point equal to or higher than the heating temperature is used as the resin material.   The method for producing resin fine particles according to claim 1, wherein the resin material has a glass transition point of 50 to 120 ° C.   The method for producing resin fine particles according to claim 1 or 2, wherein the resin material has a water absorption of 3.0 wt% or less.   The method for producing resin fine particles according to claim 1, wherein the resin material is mainly composed of a thermosetting resin.   The method for producing resin fine particles according to claim 4, wherein the thermosetting resin is an epoxy resin.   6. The method for producing resin fine particles according to claim 1, wherein the dispersion liquid is intermittently ejected by a piezoelectric pulse.   The head unit that discharges the dispersion includes a dispersion storage unit that stores the dispersion, a piezoelectric body that applies a piezoelectric pulse to the dispersion stored in the dispersion storage, and the dispersion using the piezoelectric pulse. The method for producing resin fine particles according to claim 1, further comprising: a discharge portion that discharges water.   The method for producing resin fine particles according to claim 1, wherein the resin fine particles are toner particles.   A resin fine particle produced by the method for producing a resin fine particle according to claim 1.   The resin fine particles according to claim 9, having an average particle diameter of 2 to 20 μm.   The resin fine particles according to claim 9 or 10, wherein the water content is 4.0 wt% or less.   The resin fine particles according to any one of claims 9 to 11, wherein the standard deviation of the particle diameter between the particles is 1.5 µm or less. The resin fine particles according to any one of claims 9 to 12, wherein an average circularity R represented by the following formula (I) is 0.95 or more.
R = L ₀ / L ₁ (I)
(Where, L ₁ [μm] is the circumference of the projected image of the resin fine particle to be measured, and L ₀ [μm] is the circumference of a perfect circle having an area equal to the area of the projected image of the resin fine particle to be measured) Represents length)   The resin fine particles according to any one of claims 9 to 13, wherein a standard deviation of an average circularity between the particles is 0.015 or less. The resin fine particle according to any one of claims 9 to 14, having a bulk density of 0.34 g / cm ³ or more.

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