JPH11288132A - Production of electrostatic charge image developing toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method to separate, to recover and to effectively use fine particles and/or coarse particles which are produced in the production process of toner and which are not objective. SOLUTION: The production of spherical toner includes a step of mixing an aq. medium with a mixture of a coloring agent and a binder resin as the essential components to inverse the phases for emulsification to form color particles, a step of separating the particles from the liquid medium and a step of drying to obtain toner particles. In this method, fine particles and/or coarse particles are separated and recovered by wet classification or dry classification and then the particles are used again as the source material. Even when the fine particles and/or coarse particles other than the objective toner in the toner particles are separated, recovered and reused as the source material of the toner by a phase inversion emulsification method, the toner characteristics of the toner thus produced are almost same as the characteristics of a toner without using a reused material. Therefore, the reuse of the source material is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an electrostatic image developing toner used in an electrophotographic copying machine, a printer, a facsimile and the like.

[0002]

2. Description of the Related Art As a method for producing a toner for developing an electrostatic charge image,
In the dry production method, there is a so-called pulverization method in which a colorant, a charge control agent, a wax, etc. are added to the binder resin, melt-kneaded, pulverized, and classified, and in the wet production method, the colorant and the charge control agent are dispersed. There is a so-called polymerization method in which the polymerizable monomer is polymerized in a liquid medium to produce toner particles.

The volume average particle diameter of the toner for electrostatic charge development is 7 to
Although it is in the range of about 15 μm, it is necessary to make the particle size distribution as sharp as possible in order to express good chargeability. Therefore, in the pulverization method, classification is one of the indispensable manufacturing steps. It is desirable from the viewpoint of cost reduction and industrial waste reduction that the fine particles or coarse particles separated in the classification process are reused as a part of the raw material. Composition ratio of the resin, colorant, charge control agent, wax, etc.)
The composition of the target toner particles is slightly different,
A toner produced by collecting and reusing fine particles and the like from the classification process as a raw material has a slight difference in chargeability and the like as compared with a toner produced only from a pure raw material, and is industrially very difficult.

Further, it is basically impossible to reuse the fine particles or coarse particles separated in the classification step as a raw material in the polymerization method toner, and it is necessary to make the particle size distribution as sharp as possible in the polymerization granulation step. Effort has been made.

A so-called phase inversion emulsification method described in JP-A-5-66600 and the like is known as a new wet method for producing a toner. This involves mixing a mixture (A) containing a resin and a colorant which can become self-water dispersible by neutralization with an aqueous medium in the presence of a neutralizing agent and phase inverting and emulsifying to form spherical colored particles. Then, the particles are separated from a liquid medium and dried to produce a spherical toner. In this method, spherical particles having a fairly good particle size distribution are generally obtained. However, in order to impart excellent performance as a toner, it is preferable to separate and remove fine particles and coarse particles contained in a small amount.

[0006] Fine particles and coarse particles contained in the toner particles produced by the phase inversion emulsification method need to be effectively utilized from the viewpoint of cost reduction and industrial waste reduction, and technical development has been desired. .

[0007]

That is, an object of the present invention is to separate a small amount of fine particles or coarse particles contained in toner particles produced by a phase inversion emulsification method and to reuse the toner as a raw material. It is to provide a manufacturing method of.

[Means for Solving the Problems]

The inventors of the present invention have conducted intensive studies with an eye on the problems to be solved by the present invention as described above, and as a result, have found that fine particles other than the object contained in the toner particles produced by the phase inversion emulsification method. Particles and coarse particles are separated by wet classification of particles in a liquid medium and / or by dry classification of powder particles after drying. It has been found that the above-mentioned problems can be solved without being affected.

A method for producing a toner by the phase inversion emulsification method is as follows. That is, a mixture (A) containing a binder resin and a colorant as essential components is mixed with an aqueous medium (water or a liquid medium containing water as a main component) to be phase-inverted and emulsified. This is a method in which encapsulated spherical colored particles are formed, the particles are separated from a liquid medium, and dried to form toner particles. Mixture of binder resin and colorant in this case (A)
May be prepared by using an organic solvent as described in JP-A-5-66600,
As described in 311502, it may be produced by a method of heating and melting without using an organic solvent.

The toner production method of the present invention is most preferably applied to toner particles which undergo phase inversion emulsification without using an emulsifier, using a resin having self-water dispersibility by neutralization as a binder resin. It is also preferable to use a resin having no self-water dispersing property as a resin to be applied to toner particles to be phase-inverted and emulsified using an emulsifier or a dispersion stabilizer. The phase inversion emulsification method in which particles are formed without using an emulsifier or a dispersion stabilizer is easier to wash the toner particles and has better environmental stability, and is more suitable for the present invention.

First, a method for producing toner particles by using a resin which becomes self-water dispersible by neutralization as a binder resin will be described. This is a method in which a mixture containing a resin and a colorant that become self-water dispersible by neutralization as essential components is mixed with an aqueous medium in the presence of a neutralizing agent, and resin particles obtained by phase inversion emulsification are separated. And drying the toner.

The binder resin that can be used for the toner particles according to this method may be any resin that can be used as a toner binder resin, but it is relatively easy to balance the powder fluidity and the fixability of the toner. A styrene acrylic resin or a polyester resin which is easily obtained is particularly preferable.

In the present invention, the resin capable of becoming self-water dispersible by neutralization is defined as an emulsifier or dispersant under the action of an aqueous medium due to the function of a functional group in the molecule which can increase hydrophilicity by neutralization. A resin having the ability to form a stable aqueous dispersion or aqueous solution without substantially using a stabilizer. If the resin that can become self-water dispersible by neutralization (resin having an acidic or basic functional group in the molecular chain that can increase hydrophilicity by neutralization) has an acidic group If the base has a basic group, it can be neutralized with an acid to make the functional group a salt structure and enhance the hydrophilicity.

The degree of hydrophilicity can be appropriately adjusted by the degree of neutralization (neutralization rate). The degree of hydrophilicity at this time must be such that the resin itself can be dispersed in water. When such a self-water-dispersible resin is mixed with an aqueous medium, phase inversion emulsification occurs to form particles.

The hydrophilicity of a resin containing an acid group or a basic group and capable of becoming self-water dispersible by neutralization is determined by the amount of a functional group capable of increasing the hydrophilicity by neutralization or the amount of neutralization (neutralization ratio). Can be controlled by A self-water-dispersible resin can be obtained by using a resin that becomes water-soluble when neutralized to a certain degree of neutralization or higher and reducing the degree of neutralization.

The size of the particles formed in the phase inversion emulsification is determined by the degree of such hydrophilicity. That is, an arbitrary particle size can be easily obtained by controlling the neutralization ratio.

Examples of the functional group of the resin that can increase hydrophilicity by neutralization in the resin include, for example, acidic groups such as carboxyl group, phosphoric acid group, sulfone group and sulfuric acid group. preferable. Also,
Examples of the basic group include a primary, secondary, tertiary amino group, and quaternary ammonium group, and among them, a tertiary amino group is preferable. The amount of neutralized functional groups such as acidic groups or basic groups (neutralization amount, neutralization ratio) required for the resin to exhibit self-water dispersibility or water solubility depends on the composition, molecular weight, and structure. Since the hydrophilicity of the resin itself is different depending on, for example, the degree of neutralization is different depending on each resin.

The acidic group-containing styrene acrylic resin which can become self-water dispersible by neutralization includes a radical polymerizable monomer containing an acid group and a radical polymerizable monomer containing the acid group. Can be used which are obtained by radical polymerization of the radically polymerizable monomers in the presence of a radical initiator.

The basic group-containing resin which can be made self-water dispersible by neutralization includes a polymerizable monomer containing a basic group and a polymerizable monomer other than the polymerizable monomer containing a basic group. Those obtained by subjecting a polymerizable monomer to radical polymerization in the presence of a radical initiator can be used. The polymerization reaction for obtaining these can be suitably used in solution polymerization, suspension and emulsion polymerization.

Such acidic group-containing polymerizable monomers include, for example, acrylic acid, methacrylic acid, crotonic acid,
Examples include itaconic acid, maleic acid, fumaric acid, monobutyl itaconate, monobutyl maleate and the like. Also,
Examples of the basic group-containing polymerizable monomers include acrylate derivatives such as dimethylaminoethyl, diethylaminoethyl, dibutylaminoethyl, and N-ethyl-N-phenylaminoethyl, and methacrylate derivatives.
Also, N-vinyl pyrrole, N-vinyl carbazole,
N- such as N-vinylindole and N-vinylpyrrolidone
Vinyl compounds are also included.

Examples of the polymerizable monomer other than the polymerizable monomer containing an acidic group or a basic group include styrene-based monomers (aromatic vinyl monomers) such as styrene, vinyltoluene, and 2-methylstyrene. , T-butylstyrene or chlorostyrene.

Examples of the acrylates include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate, acryl 2-ethylhexyl acrylate, n-octyl acrylate, decyl acrylate or dodecyl acrylate, 2-chloroethyl acrylate,
Examples include phenyl acrylate and methyl alpha-chloroacrylate.

Examples of the methacrylate include methyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, and n-methacrylic acid. Octyl, decyl methacrylate, dodecyl methacrylate, 2-chloroethyl methacrylate, phenyl methacrylate, and alpha-methyl methacrylate.

Also, acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone. And vinyl ketones.

When the above resin is obtained, a general-purpose organic solvent can be used in the case of solution polymerization. Examples of the organic solvent used include various hydrocarbons such as toluene, xylene, benzene, n-hexane, cyclohexane and n-heptane; methanol, ethanol, isopropanol, n-propanol, n-butanol, isobutanol, sec- Alcohols such as butanol and t-butanol; propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monoisopropyl ether, propylene glycol mono n-butyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether; Ether alcohols such as ethylene glycol mono n-butyl ether; acetone, methyl ethyl ketone, Various ketones such as butyl isobutyl ketone; various esters such as ethyl acetate, butyl acetate and isobutyl acetate; various ether esters such as propylene glycol monoethyl ether acetate and ethylene glycol monoethyl ether acetate; various cyclic ethers such as tetrahydrofuran Various organic solvents such as various halogenated hydrocarbons such as methylene chloride;

As the polymerization initiator to be used, various commonly used organic peroxide-based initiators and azo-based initiators can be used. Specifically, for example, peroxides such as benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, sodium persulfate and ammonium persulfate, and azo-based compounds such as azobisisobutyronitrile and azobisisovaleronitrile Compounds.

The acid group-containing styrene acrylic resin used in the binder resin of the toner particles of the present invention may have an acid value of 30 to 30.
150 (mgKOH / g), mass average molecular weight 6,000-
Those having a composition such as 300,000 and a glass transition temperature of 50 to 70 ° C. are suitable.

The basic group-containing styrene acrylic resin includes an amine value of 20 to 100 (mg HCl / g),
Weight average molecular weight 10,000 to 400,000, preferably 20,000 to 300,000, glass transition temperature 50 to 70
° C is preferred.

As the polyester resin having an acidic group used for the binder resin of the toner particles of the present invention, a known and commonly used polyester resin for toner can be used. Such a polyester resin can be produced by performing dehydration polycondensation of a raw material polybasic acid and a polyhydric alcohol in the presence or absence of a solvent in the presence of a catalyst. A portion of the polybasic acid may be subjected to demethanol polycondensation using its methyl esterified product, which is one of its ester-forming derivatives.

Examples of the polybasic acid include terephthalic acid,
Aromatic carboxylic acids such as isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid, maleic anhydride, fumaric acid, succinic acid,
Examples include aliphatic carboxylic acids such as alkenyl succinic anhydride and adipic acid, and alicyclic carboxylic acids such as cyclohexanedicarboxylic acid. One or more of these polybasic acids can be used.

Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, butanediol,
Hexanediol, neopentyl glycol, aliphatic diols such as glycerin, cyclohexanediol,
Examples include alicyclic diols such as cyclohexanedimethanol and hydrogenated bisphenol A, aromatic diols such as ethylene oxide adduct of bisphenol A and propylene oxide adduct of bisphenol A. One or more of these polyhydric alcohols can be used.

The glass transition point of the polyester resin is 50 to
The temperature is preferably 75 ° C, more preferably 55 to 70 ° C.
° C. If the glass transition point is less than 50 ° C., the heat cohesion of the toner becomes poor, and if it exceeds 75 ° C., the fixability becomes poor, which is not preferable.

The content of the acid group of the polyester resin is determined by the mixing ratio of the polybasic acid and the polyhydric alcohol and the reaction rate.
It can be adjusted by controlling the terminal carboxyl group of the polyester. Alternatively, a polyester having a carboxyl group in the main chain can be obtained by using trimellitic anhydride as the polybasic acid component. The content of the acid group of the polyester resin is 1 as an acid value.
３０30 mg · KOH / g is preferred.

The neutralizing agent used in the present invention must be properly used as follows. In order to convert the acidic group-containing resin to self-water dispersibility, a basic neutralizing agent is used, and in order to convert the basic group-containing resin to self-water dispersibility / or water solubility, an acidic Is used. In addition, an acidic neutralizing agent is used to return the acidic group-containing resin having a salt structure due to neutralization to the original acidic group. In addition, a basic neutralizing agent is used in order to return the basic group-containing resin, which has become a salt structure by neutralization, to the original basic group and precipitate the resin on the surface of the resin particles.

Examples of the basic neutralizer include inorganic metals such as sodium hydroxide, potassium hydroxide and lithium hydroxide, inorganic alkalis such as ammonia, alkanolamines such as monoethanolamine and diethanolamine, and dimethylamine. , Secondary amines such as diethylamine, tertiary amines such as triethylamine, organic amines such as hydrazine, acidic compounds such as hydrochloric acid, sulfuric acid, inorganic acids such as phosphoric acid, oxalic acid, formic acid, acetic acid, succinic acid,
Organic acids such as p-toluenesulfonic acid can be mentioned, and these are used in an appropriate amount.

Next, a method for producing toner particles using a water-insoluble resin which does not disperse in water by itself, ie, does not have self-water dispersibility, as a binder resin will be described. In this case, the mixture (A) and / or an aqueous medium mixed therewith (the aqueous medium refers to water or a liquid medium containing water as a main component) is used by adding an emulsifier and / or a dispersion stabilizer. It is necessary.

As the dispersion stabilizer, a water-soluble polymer compound is preferable, and examples thereof include polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, and carboxymethyl cellulose. Examples of the emulsifier include various nonionic surfactants such as polyoxyethylene alkylphenol ether, and various anionic or cationic surfactants such as sodium alkylbenzenesulfonate. Of course, two or more kinds of emulsifiers may be used in combination, two or more kinds of dispersion stabilizers may be used in combination, or an emulsifier and a dispersion stabilizer may be used in combination. It is common to use an emulsifier in combination.

In this case, when an emulsifier or a dispersion stabilizer is used, its concentration in the aqueous medium is suitably adjusted to about 0.5 to 3% by mass.

Further, even when a resin which can be made self-water dispersible by neutralization as described above is used, if necessary, the emulsifier and / or the dispersion stability can be used as long as the effects of the present invention are not impaired. Agents may be used.

As the coloring agent used in the present invention, general-purpose coloring agents can be used. Specifically, for example, carbon black, magnetic powder, aniline blue, calcoil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengalara, C.
I. Pigment Red 122, C.I. I. Pigment Yellow 97, C.I. I. Pigment Blue 15, iron trioxide, iron sesquioxide, iron powder, zinc oxide, etc., and can be used alone or in combination of two or more.

The amount of the colorant used is usually 100
It is selected from the range of 3 to 15 parts by mass per part by mass.

In the present invention, when an organic solvent is used for preparing the mixture (A) containing a binder resin and a colorant as essential components, any organic solvent may be used as long as it can dissolve the resin used. A solvent may be used. Further, the organic solvent used in the resin synthesis may be used as it is. As described above, for example, aromatic hydrocarbon solvents such as toluene, xylene, and benzene, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, ether solvents such as tetrahydrofuran, and halogen solvents such as carbon tetrachloride, trichloromethane, and dichloromethane. Solvents are used. In this case, for example, the combined use of a water-soluble or partially water-soluble organic solvent such as acetone, butanol, or isopropyl alcohol facilitates the generation of particles in phase inversion emulsification.

Preferably, the use of so-called low boiling solvents, such as acetone, methyl ethyl ketone or ethyl acetate, tetrahydrofuran, which can be easily removed, is suitable.

In the present invention, a known and commonly used charge control agent for toner can be used. Examples of such charge control agents include metal-containing azo compounds, metal compounds of salicylic acid derivatives, nigrosine, quaternary ammonium salt compounds, and metal-free resin-based charge control agents.

As other constituent components (additive components) of the toner particles, various auxiliaries such as a release agent can be mentioned, and they can be appropriately selected and used according to the purpose of use and the conditions of use. Can be done. For example, polyethylene wax, polypropylene wax, waxes such as paraffin wax, metal soap, lubricants such as zinc stearate, etc., among them, among others, aqueous dispersion of synthetic wax synthesized by Fischer-Tropsch method, or emuljo type These can be added to the resin solution before phase inversion emulsification, and after phase inversion emulsification, can be included in the particles.

Next, a method for producing spherical toner particles by the phase inversion emulsification method will be described. This production method includes a step (1) of preparing a mixture (A) containing a colorant and a binder resin as essential components, a step (2) of mixing the mixture (A) with an aqueous medium and inverting and emulsifying the mixture to form colored particles, (3) separating the colored particles from the liquid medium and drying to obtain toner particles.

In the production method of the present invention, in the above step (3), fine particles and / or coarse particles are separated and recovered, and reused as a raw material of the mixture (A) in the step (1).
This is for producing spherical toner particles.

The method of separating and recovering fine particles and / or coarse particles can be roughly classified into a dry method and a wet method. Even in the method of the present invention, classification and recovery are performed in the step (3) where the phase inversion emulsification is completed. The dry classification method is a method of separating and collecting undesired fine particles and / or coarse particles from the dried toner particles in the step (3) using a known and commonly used classifier. Such a classifier is not particularly limited, and a commercially available classifier can be used. For example, Microcut (Yasukawa Shoji), TAYPLEX ATP (Hosokawa Micron), Elbow Jet (Nippon Steel Mining), Spedik Classifier ( Seisin companies).

In the wet classification method, in step (3), the liquid medium slurry of the toner particles before drying is converted into undesired fine particles and / or coarse particles by utilizing the difference in sedimentation speed depending on the particle diameter. A method of separating and collecting is provided. Although natural sedimentation by gravity difference may be used, classification by sedimentation speed difference using a centrifugal separator is efficient and preferable industrially. For example, if a commercially available basket-type centrifugal separator equipped with a skimming device is used, unintended fine particles and / or coarse particles can be separated from a liquid medium slurry of toner particles. At this time, the slurry concentration is preferably about 2 to 30% by mass, particularly preferably 5 to 20% by mass for efficient classification.
The centrifugal effect varies depending on the average particle size of the target toner particles, but is preferably about 300 to 10000 G, particularly preferably about 600 to 6000 G. If the centrifugal effect is too small, it takes a long time and the working efficiency is poor. If the centrifugal effect is too high, aggregation between toner particles undesirably occurs. The separation of the fine particles and the separation of the coarse particles by the centrifugal separator can be performed by a batch system or a continuous system.

As another wet method, a liquid medium of toner particles can be passed through a filter using a pump to separate particles larger than a target particle diameter.

The unintended fine particles / coarse particles separated and recovered by the dry method or the wet method as described above are subjected to the step (1) in step (1).
Used as a raw material for binder resin and colorant. The fine particles / coarse particles collected by the dry method may be used as raw materials for the binder resin and the colorant, and the fine particles / coarse particles collected by the wet method may be dried or wet caked. What is necessary is just to use it as a raw material of a binder resin and a coloring agent as it is.

In the step (1), the binder resin is dissolved in a solvent, and a colorant or the like is added thereto, and the mixture is sufficiently mixed and dispersed to form a mixture (A). The powder or wet cake of the fine particles and / or coarse particles separated and recovered in step (1) is added. The mixing and dispersing machine used at this time is not particularly limited, but it is preferable to use generally used Despa, various types of bead mills, ball mills, and sand mills.

In step (1), when no organic solvent is used, the binder resin and the colorant are sufficiently mixed and dispersed using a two-roll, kneader, twin-screw extruder, or the like, and the mixture (A) is dispersed. In the present invention, the fine particles and / or coarse particles separated and recovered in the step (3) are added.

In the step (2), the mixture (A) of the binder resin and the colorant thus prepared is mixed with an aqueous medium to phase invert and emulsify to form spherical colored particles containing the colorant. I do. This mixing may be performed in a kettle equipped with a stirring blade such as a Max Blend blade, or a batch type disperser such as a homomixer or Despa may be used. Further, a continuous emulsifying and dispersing machine such as Slasher (Mitsui Mining Co., Ltd.) or Cavitron (Eurotech Co., Ltd.) may be used.

In this case, when a resin capable of becoming a self-water-dispersible resin by neutralization is used as the binder resin, the above-described neutralizing agent is dissolved in the mixture (A) or the aqueous medium. When a resin having no self-water dispersibility is used, an aqueous medium containing the above-described emulsifier or dispersion stabilizer is used.

In the step (3), when an organic solvent is used, the organic solvent is removed from the aqueous dispersion after the phase inversion emulsification, the aqueous medium is separated by filtration, the wet cake is washed, and then dried. Obtain a powder toner. When an acidic group-containing resin having self-water dispersibility by neutralization is used as the binder resin, the wet cake is re-dispersed in an aqueous medium before the drying step, and the acidic group-containing resin is dispersed with an aqueous hydrochloric acid solution. Is preferably returned to the original acidic group.

The drying can be performed by any known and commonly used method. For example, the drying may be performed by heating at a temperature at which the toner particles do not fuse or aggregate, or a freeze-drying method. There is also a method in which separation and drying of toner particles from an aqueous medium and drying are performed simultaneously using a continuous instantaneous air-flow dryer or a spray dryer.

The toner particles produced in the present invention have a spherical shape when observed with an optical microscope or an SEM (scanning electron microscope), and have a Wardell practical sphericity of 0.95 or more.

When the cross section of the toner particles produced in the present invention embedded in a resin and cut by a microtome is observed with a TEM (transmission electron microscope), it is clear that the colorant, wax and the like are contained in the binder resin. I understand.

In the method for producing a toner according to the present invention, the composition of the fine particles and the coarse particles is the same as the composition of the target toner particles, and the colorant and the like of the toner particles are included in the binder resin. Even if fine particles and coarse particles are separated and collected and reused as a raw material, no difference occurs in toner characteristics such as chargeability and fixability.

The toner particles obtained by the production method of the present invention can be used as they are as toners for developing electrostatic images.
It is preferable from the viewpoint of powder fluidity and chargeability control to be used as a toner for developing an electrostatic image by externally adding inorganic fine particles such as alumina and various organic fine particles. The method of external attachment is
A known method such as a Henschel mixer or a hybridizer may be used.

The size of the toner particles of the present invention can be arbitrarily selected within a practical level as a toner. In view of the matching property with the current machine, it is preferable that the volume average particle diameter is in the range of 6 to 13 μm.

The toner of the present invention can be used as a non-magnetic one-component toner or a magnetic one-component toner, or can be used as a two-component developer by combining with a carrier. Obtainable.

As the carrier, any known and commonly used carriers can be used. For example, iron, nickel, copper, zinc,
Metals such as cobalt, manganese, chromium, and rare earths, and alloys or oxides thereof, and powders of surface-treated glass and silica can be used. Of course, resin-coated carriers such as an acrylic resin-coated carrier, a fluororesin-coated carrier, a fluorine / acrylic resin-coated carrier, and a silicone resin-coated carrier can also be used. As a carrier, for example, 20
Those having a size of about 200 μm are used.

[0065]

BEST MODE FOR CARRYING OUT THE INVENTION 1) Separating particles containing a colorant, which are obtained by mixing a mixture (A) containing a binder resin and a colorant as essential components with an aqueous medium and emulsifying the mixture by phase inversion, from the liquid medium. And
In a method for producing a toner for electrostatic charge development by drying,
A method for producing a spherical toner, comprising separating fine particles and / or coarse particles in the production step and using the separated particles as part or all of the raw material of the mixture (A).

2) The method for producing a toner as described in 1 above, wherein a resin capable of becoming self-water dispersible by neutralization is used as the binder resin.

3) The toner has a practical sphericity of 0. Wader.
3. The method for producing a toner according to 1 or 2, wherein the toner has a spherical shape of 95 or more.

In the most preferred embodiment of the present invention, a self-water-dispersible resin containing an acid group is used as the binder resin.

Next, the present invention will be specifically described with reference to comparative examples and examples. The present invention is not limited to the following examples unless it exceeds the gist. Hereinafter, “parts” and “%” in Examples and Comparative Examples are all based on mass.
All water means deionized water.

(Reference Example) Synthesis Example of Carboxyl Group-Containing Styrene Acrylic Resin In a 3-liter flask equipped with a dropping device, a thermometer, a nitrogen gas inlet tube, a stirring device, and a reflux condenser, methyl ethyl ketone / isopropyl alcohol / water 114 was added. / 12/24
After the parts were charged, the temperature was raised to 80 ° C., and the mixture comprising the monomers of Composition 1 and the polymerization initiator was batch-started to start the charging reaction.

Composition 1 330 parts of styrene 216 parts of butyl acrylate 54 parts of acrylic acid “Perbutyl O” (manufactured by NOF Corporation) 0.6 part

Then, every three hours after one hour, about 10 parts of the reaction resin solution was sampled, diluted with the same amount of methyl ethyl ketone, and the viscosity was measured with a Gardner viscometer. When the viscosity becomes PQ, methyl ethyl ketone /
567/63 parts of isopropyl alcohol were added, and after the temperature reached 80 ° C., a mixture having a ratio as shown in composition 2 was added dropwise over 1 hour. At this time, the polymerization rate of the first stage was calculated by quantifying the residual monomer ratio by gas chromatography and found to be 60%.

Composition 2 Styrene 413 parts Butyl acrylate 133 parts Acrylic acid 54 parts “Perbutyl O” 18 parts

After the completion of the dropwise addition, 2 parts of “perbutyl O” was added three times every three hours, and the reaction was continued for another four hours. Finally, the non-volatile content is 5 with methyl ethyl ketone.
It was adjusted to 0% to obtain a resin solution. This resin has an acid value (KOH required to neutralize 1 g of resin solids)
Mg, 70, mass average molecular weight 124000, Tg6
1 ° C.

For the sake of explanation, a comparative example in which the recovered raw materials are not used will be described first. (Comparative Example 1) 900 parts of the resin solution prepared in Reference Example,
50 parts of "ELFTEX 8" (carbon black manufactured by Cabot Corporation, USA) was kneaded using "Eiger Motor Mill M-250" (motor mill manufactured by Eiger Japan). The mill base resin solids / pigment ratio is 90/10.

To the resulting carbon black-dispersed resin solution was added a wax fine particle liquid medium dispersion “H808” (emulsion type wax, Fischer-Tropsch wax manufactured by Chukyo Yushi Co., Ltd., particle diameter 0.5 μm, solid content 30).
%), And mixed and dispersed by “Eiger motor mill M-250”. Then
Adjust the nonvolatile content to 51% with methyl ethyl ketone,
A mill base was prepared.

Then, 1N aqueous sodium hydroxide solution (neutralizing agent) was added to 300 parts of the mill base.
After adding 7 parts, 34 parts of isopropyl alcohol, 30 parts of methyl ethyl ketone, and 90 parts of water and mixing well, water (30 ° C.) is added while stirring and maintaining the internal temperature at 30 ° C., and phase inversion emulsification is performed to obtain colored particles. And after 30 minutes 300 of water
And diluted.

Next, the organic solvent was removed by distillation under reduced pressure, the colored particles were separated from the liquid medium by filtration, and the particles were redispersed in water. Subsequently, a 1N aqueous hydrochloric acid solution was added to the dispersion to adjust the pH to 2.5, followed by stirring for 30 minutes to convert the resin in the resin particles into the original carboxyl group-containing resin.

After the obtained colored particles were filtered and washed with water, they were dried at 40 ° C. using a vacuum mixing dryer (manufactured by Tanabe Wiltech).
Drying was performed under the condition of 0.1 Torr to obtain powder particles. The average particle diameter of the powder particles was 8.0 μm, and the practical sphericity of Wardel was 0.96 or more. A cross section of the powder particles embedded in a resin and cut with a microtome was stained with ruthenium oxide, and then observed with a TEM. As a result, it was confirmed that the colorant and the wax fine particles were included in the toner particles. .

The powder particles were dry-classified using an elbow jet to obtain toner powder particles having an average particle size of 8.1 μm.

(Comparative Example 2) In Comparative Example 1, an aqueous dispersion of colored particles before treatment with hydrochloric acid was centrifuged by a centrifugal separator (manufactured by Tanabe Wiltec) with a skimming device.
The solution was treated with 0 G, and the upper liquid mainly containing fine particles was sucked out by skimming and separated. The wet cake layer containing the target toner particles was treated with hydrochloric acid in the same manner as in Comparative Example 1,
The resultant was washed with filtered water and dried to obtain toner powder particles having an average particle size of 8.0 μm.

(Comparative Example 3) An acid value of 4 mg · KOH / g,
Mass average molecular weight is 12000, glass transition point is 61 ° C,
Methyl ethyl ketone was added to 1200 parts of a polyester resin having a melt viscosity of 40000 poise at 100 ° C.
Add 00 parts and add the phthalocyanine pigment Ket Blue 123 (Dainippon Ink and Chemicals) to the well-dissolved resin solution.
48 parts were added and mixed with stirring to sufficiently disperse. After the dispersion is completed, the solid content is reduced to 50% by methyl ethyl ketone.
And adjusted to a mill base.

To 200 parts of the mill base, 86 parts of methyl ethyl ketone and 4 parts of 1N ammonia water were added, and 220 parts of water was added with stirring to carry out phase inversion emulsification to form resin particles. 150 parts of water was added as dilution water, and 4 parts of 1N aqueous ammonia was added to increase the dispersion stability.

Thereafter, in the same manner as in Comparative Example 1, solvent removal, filtration water washing, hydrochloric acid treatment, filtration water washing, and drying were performed, and the resulting powder particles were subjected to dry classification to obtain a toner powder having an average particle diameter of 7.8 μm. Particles were obtained.

The toner particles had a spherical shape with a practical sphericity of 0.96 or more by Wadel. The cross section of the particles embedded in a resin and cut with a microtome was observed with a TEM. As a result, the pigment was uniformly encapsulated in the particles. Was dispersed.

(Example 1) Resin solution 81 prepared in Reference Example
0 parts and 45 parts of carbon black, 50 particles of fine particles (average particle diameter of 6.2 μm) separated by dry classification of Comparative Example 1 50
Parts and 45 parts of methyl ethyl ketone, and kneaded using an Eiger motor mill.
Was added and mixed and dispersed to obtain a mill base. Thereafter, the same procedure as in Comparative Example 1 was carried out to obtain powder particles having an average particle diameter of 7.9 μm, and the same dry classification as in Comparative Example 1 was performed to obtain powder particles having an average particle diameter of 8.0 μm. To obtain spherical toner powder particles.

(Example 2) Resin solution 81 prepared in Reference Example
To 8 parts and 46 parts of carbon black, 60 parts of a wet cake (water content: 25%) of fine particle powder (average particle size: 6.8 μm) separated by wet classification of Comparative Example 2 and 41 parts of methyl ethyl ketone were added, and Eiger was added. The mixture was kneaded using a motor mill, and 41 parts of wax dispersion H808 was further added and mixed to form a mill base. Hereinafter, it carried out similarly to the comparative example 2,
Spherical toner powder particles having an average particle size of 8.1 μm and containing a pigment and wax in a binder resin were obtained.

(Example 3) 1123 parts of polyester resin used in Comparative Example 3, 800 parts of methyl ethyl ketone, 45 parts of phthalocyanine pigment, fine particle powder separated by dry classification of Comparative Example 3 (average particle size: 6.0 μm) Except for using 80 parts as a raw material, the same procedure as in Comparative Example 3 was carried out, and the average particle size was 7.9.
Spherical toner powder particles having a size of μm and a pigment contained in a binder resin were obtained.

(Evaluation Test of Toner) 0.3 part of hydrophobic silica R972 was added to 100 parts of each of the six kinds of toner powder particles produced in Comparative Examples 1, 2, and 3 and Examples 1, 2, and 3. And a Henschel mixer to prepare six kinds of toners for developing electrostatic images. Four parts of each of these six types of toners were mixed with 96 parts of a silicon-coated ferrite carrier, and their charge amount and reverse charge ratio were measured with an E-SPART analyzer (manufactured by Hosokawa Micron). Next, 0.1 parts of titanium oxide fine particles MT-150 (manufactured by Teica) were added to 100 parts of each of the six types of toner powder particles prepared in Comparative Examples 1, 2, and 3 and Examples 1, 2, and 3.
5 parts and hydrophobic silica Wacker HDK SLM
50650 were added and mixed with a Henschel mixer to prepare six kinds of non-magnetic one-component toners.
When an image test was performed on the seeds using an Epson LP-1700 printer, good images were obtained in all cases, and no difference was found between the examples and the comparative examples.

[0089]

[Table 1]

There is no significant difference in the amount of charge between each example and the comparative example. There is no practical problem if the reverse charging ratio is about 5% or less, and a difference within 0.5% is not a significant difference. Therefore, the characteristics shown in Table 1 are practically acceptable for each of the examples and comparative examples, and there is no significant difference between each example and the comparative example.

[0091]

According to the present invention, even if undesired fine particles and / or coarse particles contained in toner particles are separated and collected and reused as a raw material of the phase inversion emulsification toner, the toner characteristics are compared with those not reused. Thus, there was no difference, and it was found that the raw materials could be reused. Furthermore, when separating and recovering undesired fine particles and / or coarse particles contained in the toner particles, dry-classified or wet-classified products are collected and reused. I understood. Naturally, both the wet classification and the dry classification may be collected and reused. The ratio between the recovered toner and the new raw material is not particularly limited.

Further, by separating and recovering unintended fine particles and / or coarse particles contained in the toner particles produced by the phase inversion emulsification method, and reusing them as a raw material of the phase inversion emulsification method, cost can be reduced. Industrial waste can be reduced.

Claims (3)

[Claims] A mixture containing a binder resin and a colorant as essential components (A) is mixed with an aqueous medium and phase-inversion emulsification is carried out. The particles containing the colorant are separated from the liquid medium and dried. In the method of producing a toner for electrostatic charge development, characterized in that fine particles and / or coarse particles are separated in the above-mentioned production step and used as part or all of the raw material of the mixture (A). Of producing spherical toner. 2. The method for producing a toner according to claim 1, wherein a resin capable of becoming self-water dispersible by neutralization is used as the binder resin. 3. The toner has a practical sphericity of 0.95 of Wardel.
3. The method for producing a toner according to claim 1, wherein said toner is spherical.