JP2787897B2 - Electrostatic toner and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge developing toner used for developing an electrostatic latent image formed by an electrophotographic method or an electrostatic recording method, and a method for producing the same.

[0002]

2. Description of the Related Art A method for visualizing image information via an electrostatic charge image such as electrophotography is currently used in a wide range of fields. In electrophotography, an electrostatic image is formed on a photoconductor by a charging and exposing process, an electrostatic latent image is developed with a developer containing a toner, and the image is visualized through a transfer and fixing process. The developer used here includes a two-component developer including a toner and a carrier, and a one-component developer using a magnetic toner or a non-magnetic toner alone. As a method for producing these toners, a kneading and pulverizing method is generally used in which a thermoplastic resin is melt-kneaded together with a releasing agent such as a pigment, a charge controlling agent, and wax, cooled, finely pulverized, and further classified. Fine particles of an inorganic material or an organic material are added to the surface of the toner particles, if necessary, in order to improve fluidity and cleaning properties.

In a commonly used kneading and pulverizing method, the shape of the toner and the surface structure of the toner are indefinite, and vary delicately according to the pulverizability of the material used and the conditions of the pulverizing process. And it is difficult to intentionally control the surface structure. In particular, when a material having high pulverizability is used, the toner is often further pulverized due to mechanical force or the like in the developing machine, which often causes generation of fine powder or change in toner shape. These tendencies are particularly noticeable when a release agent such as wax is included. Therefore, in the case of the two-component developer, the deterioration of the chargeability of the developer is accelerated due to the fixation of the fine powder to the carrier surface. In the case of the one-component developer, toner scattering occurs due to expansion of the particle size distribution, Deterioration of image quality is likely to occur due to a decrease in developability due to a change in toner shape. In addition, when a toner is formed by internally adding a release agent such as a wax, exposure of the release agent to the surface is often affected by combination with a thermoplastic resin. In particular, in the case of a combination of a resin which is imparted with elasticity by a high molecular weight component and is hardly pulverized and a brittle wax such as polyethylene wax, polyethylene is often exposed on the toner surface. Although these are advantageous for the releasability at the time of fixing and cleaning of the untransferred toner from the photoreceptor, since the polyethylene wax of the surface layer is easily transferred by mechanical force, the developing roller or the photoreceptor, the carrier, etc. Contamination is more likely to occur, leading to lower reliability. Further, since the shape of the toner is indefinite, it is difficult to obtain a fluid having sufficient fluidity even when a fluidity aid is added, and fine particles existing on the toner surface due to mechanical force during use. Moves to the concave portion of the toner, and the fluidity decreases over time, so that developability, transferability, cleaning performance, and the like deteriorate. Further, when the toner collected by the cleaning is returned to the developing machine and used again, the image quality is more likely to deteriorate. If the addition of the flow aid is further increased to prevent these problems, problems such as generation of black spots and scattering of the flow aid particles on the photoreceptor occur.

[0004] As a method of solving these problems, it is already known to subject toner particles to spheroidizing or deformation treatment. As an example of the toner sphering treatment, a method of treating with a mechanical force such as a hybridizer or a dry treatment method such as a hot air treatment is generally used. However, the former has a problem that the spheroidization does not proceed sufficiently depending on the type of the binder resin because the time required for the processing per unit weight is long.
Since a high temperature of 0 ° C. or higher is required, the chargeability tends to be abnormal due to decomposition and oxidation of the resin, and coalescence between the toner particles proceeds to increase the processing efficiency.
There is a problem that the particle size distribution moves to the large particle size side. on the other hand,
It has also been proposed to disperse the toner particles in water by stirring, heat the particles, and maintain the toner particles at a temperature equal to or higher than the glass transition point (Tg) of the binder resin so as to make the particles spherical. For example, JP
Japanese Patent Application Laid-Open No. 2-9435 describes a method in which toner particles are dispersed in a water-miscible solvent such as water or alcohol in the presence of hydrophobic silica and heated to form a sphere. However, when a water-miscible solvent such as alcohol is used, this method is advantageous for dispersing hydrophobic silica used in combination, but it is difficult to prevent aggregation of the heat-softened toner particles, There is a problem that the concentration of the particles must be considerably reduced.When an aqueous medium is used, the hydrophobic silica completely penetrates into the inside of the hydrophobic toner particles, and a large amount of the hydrophobic silica is used. Otherwise, a material having fluidity cannot be obtained. Therefore, when a large amount of hydrophobic silica is used, there is a problem that the fixability is adversely affected.

Also, a method of dispersing a preliminarily melt-kneaded toner component in a hydrophobic solvent in water, stirring the mixture by heating and volatilizing the solvent to obtain spherical toner particles (JP-A-2-153361). Publication).
However, in such a suspension granulation method, all the toner particles are produced in a shape close to a true sphere, and it is not possible to collect an intermediate shape. For this reason, although the toner particles show good fluidity, the generally used blade cleaning method cannot pass through the blade cleaner to remove the toner remaining on the photoreceptor, or frictional charging with the carrier occurs. There is a drawback that the properties deteriorate. Therefore, in order to improve these, recently, in order to improve the cleaning property and triboelectric charging property,
Attempts have been made to provide irregularities on the surface of toner particles (JP-A-1-302270, JP-A-4-7880).
However, these methods are not practical because it is difficult to provide sufficient unevenness for improving the cleaning property and the triboelectric charging property.

[0006] In recent years, with the progress of power saving, miniaturization and speeding up of the electrophotographic method, the need for heat fixing at a low temperature has been required. In order to obtain sufficient fixability by this low-temperature fixing, it is necessary to use a polymer having a low Tg as a binder resin. However, when a polymer having a low Tg is used as the binder resin, the toner particles have a problem that the powder characteristics are deteriorated, heat aggregation occurs during storage or in a developing machine, and the toner particles are fused to the surface of the photoreceptor. Therefore,
Research and development of a capsule type toner comprising a core material having a low Tg and an outer shell having a high Tg has been advanced. This encapsulation also has the advantage that toner particles exhibiting good chargeability can be obtained irrespective of the type of core material by using a substance exhibiting stable chargeability in the outer shell. Various methods are known for encapsulation of the toner particles, such as a method of spray-drying a polymer containing a charge controlling agent onto the toner particles, or a method of obtaining toner particles by coating by heating or pressurizing (particularly, Kaisho 57-2
No. 02547, JP-A-63-27853, JP-A-63-27854, etc.) have been proposed. However, in the spray drying method, since the coating layer surrounds a plurality of toner bases, the particle size of the toner increases, and the yield of toner particles having a predetermined particle size decreases even after sieving. In addition, the use of a large amount of an organic solvent has safety and health problems. Further, the method of coating the toner base by heat fusion has a problem that the toner is inevitably adhered and aggregated, and thus the particle size of the toner is increased. Further, a method has been proposed in which resin fine particles are externally added to toner core particles produced by a kneading / pulverizing method, a polymerization method, and the like, and thereafter, the resulting solution is brought into contact with a solvent in which inorganic fine particles are dispersed to form a melt film (Japanese Patent Application Laid-Open No. H10-157572). However, this method has poor adhesion to the core material because fine particles adhere to the core material to form a coating layer, and the core material has insufficient coverage. is there. Furthermore, a method for producing microcapsules by utilizing interfacial polymerization and graft polymerization has been disclosed (Japanese Patent Application Laid-Open No. 62-22 / 1987).
However, when a polymer having a charge control function is formed in a capsule shell, there is a disadvantage that the number of steps is increased.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above-mentioned problems in the prior art in a method of kneading and pulverizing toner particles. That is,
An object of the present invention is to control the shape of the toner particles and the composition structure of the toner particle surface, thereby realizing good developability, transferability and cleaning performance, reduction of contamination of the carrier and the photoconductor, and stable chargeability. To provide a two-component developer which can be used for a longer period of time and a method for producing the same. Another object of the present invention is to control the shape of the toner particles and the composition structure of the surface of the toner particles to prevent the developing roller and the photoconductor from being contaminated, and to stably maintain good developing properties, transfer properties and cleaning properties. It is an object of the present invention to provide a one-component developer capable of achieving improved image retention and a method for producing the same. Still another object of the present invention is to provide a developer capable of obtaining stable and high image quality even when toner particles collected by cleaning are returned to a developing machine and reused, and a method of manufacturing the same.

[0008]

The toner for developing an electrostatic charge of the present invention is produced by any one of the following methods (1) to (5). The method for producing the toner includes the methods (1) to (5). (1) a step of forming fine particles of a composition comprising a binder resin and a colorant, a step of preparing a particle dispersion by dispersing the formed fine particles in an aqueous medium with a dispersant of a solid at room temperature, Preparing a non-water-miscible solvent dispersion by dispersing a hydrophobic solvent, mixing the particle dispersion and the non-water-miscible solvent dispersion, and heating and / or heating the resulting mixture.
Alternatively, there is provided a method for producing a toner for electrostatic charge development, comprising a step of removing the hydrophobic solvent by reducing the pressure to make the toner spherical or deformed. (2) binder resin, a step of forming fine particles of a composition comprising a colorant and a release agent, a step of preparing a particle dispersion by dispersing the formed fine particles in an aqueous medium with a room temperature solid dispersant, Preparing a non-water-miscible solvent dispersion by dispersing a hydrophobic solvent in an aqueous medium, mixing the particle dispersion and the non-water-miscible solvent dispersion, and heating and / or heating the obtained mixture. A method for producing a toner for electrostatic charge development, comprising a step of removing a hydrophobic solvent by reducing pressure to make the toner spherical or deformed. (3) a step of forming fine particles of a composition comprising a binder resin and a coloring agent, and dispersing the formed fine particles in an aqueous medium with a dispersant of inorganic fine particles generated in an aqueous medium to form a particle dispersion. Adjusting, dispersing a hydrophobic solvent in an aqueous medium to prepare a non-aqueous miscible solvent dispersion, mixing the particle dispersion and the non-aqueous miscible solvent dispersion, and the resulting mixture A method for producing a toner for electrostatic charge development, comprising a step of removing a hydrophobic solvent by heating and / or reducing pressure to make the toner spherical or deformed. (4) a step of forming fine particles of a composition comprising a binder resin and a colorant, and dispersing the formed fine particles in an aqueous medium with a dispersant of inorganic fine particles generated in an aqueous medium to form a particle dispersion. Preparing, dispersing a hydrophobic solvent in an aqueous medium to prepare a non-aqueous miscible solvent dispersion, mixing the particle dispersion and the non-aqueous miscible solvent dispersion, and heating the resulting mixture. And / or removing the hydrophobic solvent by reducing the pressure to make the particles spherical or deformed, and decomposing or dissolving the inorganic fine particles on the toner particles. Method. (5) a step of forming fine particles of a composition comprising a binder resin and a colorant, a step of preparing a particle dispersion by dispersing the formed particles in an aqueous medium with a dispersant of a solid at room temperature, in an aqueous medium; Dispersing a hydrophobic solvent in which the resin is dissolved to prepare a non-water-miscible solvent dispersion, mixing the particle dispersion and the non-water-miscible solvent dispersion, heating and / or heating the obtained mixture; A method for producing a toner for electrostatic charge development, comprising a step of removing hydrophobic solvent by reducing pressure to form encapsulated particles.

Hereinafter, the present invention will be described in detail. As the binder resin used in the production of the toner for electrostatic charge development of the present invention, a thermoplastic resin is used. For example, styrenes such as styrene, parachlorostyrene, α-methylstyrene, methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, methacryl N-propyl acid, lauryl methacrylate, esters having a vinyl group such as 2-ethylhexyl methacrylate, acrylonitrile, vinyl nitriles such as methacrylonitrile, vinyl methyl ether, vinyl ethers such as vinyl isobutyl ether, vinyl methyl ketone, Vinyl ketones such as vinyl ethyl ketone and vinyl isopropenyl ketone, ethylene, propylene,
Polymers such as monomers such as polyolefins such as butadiene or copolymers obtained by combining two or more of these or mixtures thereof, and further epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, Non-vinyl condensation resins such as polyether resins,
Alternatively, examples thereof include a mixture of these with the vinyl-based resin and a graft polymer obtained when polymerizing a vinyl-based monomer in the presence of these.

[0010] Examples of the coloring agent include carbon black, chrome yellow, Hansa yellow, benzidine yellow, slen yellow, quinoline yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch red, permanent red, brillantamine 3B, and brillian. Carmine 6B, Dupont Oil Red, Pyrazolone Red, Risol Red, Rhodamine B Lake, Lake Red C, Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Phthalocyanine Green, Malachite Green Oxalate Various pigments, acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioi Zico, dioxazine, thiazine, azomethine, indigo dyes, phthalocyanine,
Examples include various dyes such as aniline black, polymethine, triphenylmethane, diphenylmethane, and thiazole. One or more of these colorants can be used in combination.

In addition to the binder resin and the colorant, various substances can be added as internal additives. For example, as a magnetic substance, metals such as ferrite, magnetite, reduced iron, cobalt, nickel, and manganese and alloys thereof, or metal compounds thereof can be used, and as a charge control agent, a quaternary ammonium salt compound, nigrosine Dyes composed of a complex compound such as aluminum, iron or chromium, and a triphenylmethane pigment can be used.

In the production of the toner for electrostatic charge development of the present invention, when a release agent is contained, it is added as an internal additive and kneaded together with the binder resin and the colorant. Specific examples of the release agent to be used include polyethylene,
Low molecular weight polyolefins such as polypropylene and polybutene, silicones softened by heating, fatty acid amides such as oleamide, erucamide, ricinoleamide, and stearamide, and carnauba wax;
Minerals such as rice wax, candelilla wax, vegetable wax such as wood wax, jojoba oil, animal wax such as beeswax, montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, petroleum wax, And modified products thereof. When these release agents are combined with a commonly used thermoplastic binder resin, when a wax containing a high-polarity wax ester such as carnauba wax or candelilla wax is used, the toner surface is formed by a spheroidizing treatment. Exposure of the wax tends to increase. Conversely, when a wax having a small polarity such as polyethylene wax or paraffin wax is used, the exposure to the toner surface tends to decrease. Further, when a release agent having a melting point of 100 ° C. or more is used as in the case of ordinary polypropylene wax, the amount of exposure on the toner surface does not change by heating in water. The release amount of the release agent varies depending on the compatibility with the binder resin, the melting point of the wax, and the like. However, the release agent on the toner particle surface can be adjusted in consideration of the polarity of the release agent described above. .

In the present invention, first, a composition containing the above-described binder resin, a colorant, and, if necessary, various additives such as a release agent is kneaded, and the resulting mixture is pulverized or pulverized and classified. Is formed. These steps can be performed by a conventionally known method. For example, the mixture is kneaded by a Banbury mixer, finely pulverized by a jet mill, and classified by a sieve to give an average particle size of 4.
Fine toner particles in the range of 0 to 15.0 μm can be obtained. However, the classification step can be omitted.

Next, a particle dispersion of the obtained toner fine particles is prepared in an aqueous medium using a room temperature solid dispersant. A water-soluble polymer and inorganic fine particles are used as a dispersant of a solid at room temperature. Examples of the water-soluble polymer include cellulose compounds such as carboxymethylcellulose and hydroxypropylcellulose, polyvinyl alcohol, gelatin, starch, gum arabic, polyethylene glycol, polypropylene glycol and the like. The content of these water-soluble polymers in an aqueous medium is from 0.1 to
It is preferably in the range of 5.0% by weight. Further, as the inorganic fine particles, silica, alumina, titania, calcium carbonate, magnesium carbonate, tricalcium phosphate,
Water-insoluble fine particles such as clay, diatomaceous earth, and bentonite are exemplified. In this case, after the spheroidizing treatment, an acid treatment is performed by adding hydrochloric acid or the like to dissolve the fine powder on the surface of the toner particles, and then the toner particles are taken out by filtration. It can be as small as possible. The dispersant of the present invention may be inorganic fine particles generated in an aqueous medium. For example, inorganic fine particles may be formed by adding two types of water-soluble compounds that produce the above-mentioned poorly water-soluble fine particles to an aqueous medium. In this case, the particle size of the inorganic fine particles in the water can be controlled by devising the stirring conditions, concentration, and addition method. Specifically, calcium carbonate,
Tricalcium phosphate, silica, etc. are easy to generate and disappear fine particles in the dispersion system of toner particles,
It can be formed in this way. The content of these inorganic fine particles in the aqueous medium is 0.0
It is preferably in the range of 1 to 3.0% by weight. Examples of the aqueous medium containing the dispersant include water or water-compatible methanol, ethanol, propanol, isopropanol, ethylene glycol, acetonitrile,
It is preferable to use a mixed solvent in which acetone and ether are mixed at 0.1 to 5.0% by weight.

In the aqueous medium, a surfactant can be used to disperse the toner particles in water.
Thereby, the stability of the distributed processing can be improved. You. As the surfactant, a sulfate ester salt,
Anionic surfactants such as sulfonate and phosphate esters, cationic surfactants such as amine salts and quaternary ammonium salts, and polyethylene glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols A nonionic surfactant is used, and its use amount is preferably in the range of 0.01 to 2.0% by weight.

Next, a non-water-miscible solvent dispersion is prepared by dispersing a hydrophobic solvent in an aqueous medium. Examples of the hydrophobic solvent include hexane, cyclohexane, methylcyclohexane, benzene, toluene, dichloromethane, chloroform, carbon tetrachloride, ethyl chloride, methylene chloride,
1-dichloroethane, methyl chloroform, nitromethane, nitropropane, diethyl ether, acrylonitrile, methyl acetate, ethyl acetate, isobutyl acetate, carbon disulfide and the like can be used, and if necessary, one or more kinds can be mixed. Can be used. The mixing ratio of the hydrophobic solvent and the aqueous medium is preferably in the range of 2:98 to 30:70.

In order to disperse the hydrophobic solvent in the aqueous medium, it is necessary to add a surfactant and to disperse the hydrophobic solvent as finely as possible using a high-speed stirrer such as a homodiperser. It is important to prevent the occurrence of. The surfactant to be used is an oil-soluble surfactant, such as a carboxylate salt, a higher alcohol (thioalcohol) sulfate ester salt, an alkyl sulfonate salt, an alkyl allyl sulfonate salt, Anionic surfactants such as amide sulfonic acid salts, cationic surfactants such as higher amine salts and higher alkyl quaternary ammonium salts;
Examples include nonionic surfactants such as polyethylene glycol and polyhydric alcohol fatty acid esters.

In the present invention, the above-mentioned particle dispersion and a non-water-miscible solvent dispersion are mixed, and the resulting mixture is heated and / or reduced in pressure to remove the solvent.
A spherical or deformed toner can be obtained. When the toner obtained by kneading and pulverizing the toner composition is formed into a sphere, usually, a change in shape due to mechanical force is less likely to occur.
Further, since the selectivity of the toner particle diameter in the development and transfer steps is relaxed, the maintenance of the developer is facilitated, and in particular, the toner remaining on the photosensitive member is cleaned and collected, and the toner used for image formation is again used. When used in a recycling development system, the durability of the developer can be significantly improved. The degree of spheroidization, even if it is not completely spheroidized, can improve the durability, transferability, maintainability, chargeability and cleaning properties by smoothing the surface of the pulverized toner or deforming the protrusions so as to round them. Become. In the present invention, since the toner production method uses a non-water-miscible solvent, the processing temperature, time, the type and amount of the dispersion stabilizer, and the type and use of the solvent accompanying the difference in the solubility of the binder resin are different. By appropriately changing the amount, it is possible to arbitrarily produce various shapes from a true sphere to a rounded amorphous shape. It is particularly effective to use a blade cleaning method for producing an intermediate toner.

In order to prevent toner particles from coalescing during the sphering treatment of the toner, a water-soluble polymer such as polyvinyl alcohol or gum arabic may be dissolved in water as a dispersion stabilizer. The sphering process can be performed quickly in almost the same state as the particle size distribution. Furthermore, after making it spherical by heat treatment, it is cooled,
After filtration and washing, the desired toner particles can be obtained by crushing and sieving (classifying) as necessary. Further, by optimizing the heating temperature, time, stirring speed and the like, it is possible to narrow the particle size distribution while suppressing coalescence. In this case, the toner does not necessarily have to be classified.

In the spheroidization or deformation of the present invention, a resin having a higher glass transition point than a binder resin is dissolved in a non-water-miscible solvent, and the solvent is volatilized by heating and / or reducing the pressure to form toner particles. When obtaining an encapsulated toner for forming a coating layer on the surface, without increasing the number of steps, and without increasing the particle size of the toner,
It is possible to obtain toner particles excellent in coatability of the core material.
Further, by the encapsulation, the above-mentioned adverse effects of the amount of the surface wax can be removed, and the powder characteristics, chargeability, and service life of the toner particles can be improved.

Examples of the coating resin used in the encapsulation of the present invention include styrenes such as styrene, parachlorostyrene and α-methylstyrene, methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate. 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, methacrylic acid 2
Esters having a vinyl group such as ethylhexyl; vinyl nitriles such as acrylonitrile and methacrylonitrile; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone. , Polymers such as monomers such as polyolefins such as ethylene, propylene and butadiene;
Copolymers or mixtures thereof obtained by combining more than one kind, and further non-vinyl condensed resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, or these and the vinyl resins And a graft polymer obtained when a vinyl monomer is polymerized in the coexistence thereof. The electrostatic charge developing toner obtained as described above may be used as a one-component developer, or may be mixed with a carrier and used as a two-component developer.

[0022]

【Example】

Example 1 90 parts by weight of a polyester resin (bisphenol-propylene oxide adduct-fumaric acid) (manufactured by Kao Corporation, Mn = 5,000, Mw = 30,000, Tg = 57 ° C.) Carbon black 10 parts by weight (manufactured by Cabot Corporation) BP1300) The above composition was kneaded with a Banbury mixer, and then finely pulverized using a jet mill to obtain a toner having an average particle diameter of 7.6 μm and a particle diameter of 5 μm or less and a number average fraction of 10.0%. Fine particles were obtained. The shape of the obtained toner particles was observed with a scanning electron microscope, and it was confirmed that the particles had irregular shapes without regularity. 200 parts by weight of the toner particles are dispersed in 1,500 parts by weight of water in which 0.05% by weight of a nonionic surfactant polyoxyethylene nonylphenyl ether and 2.0% by weight of gum arabic are dissolved, and the three-one motor is used. The mixture was stirred for 30 minutes to prepare a uniform toner dispersion. Separately, 320 parts by weight of methylene chloride and 80 parts by weight of toluene are dispersed in 1,500 parts by weight of water in which 0.05% by weight of polyoxyethylene nonylphenyl ether is dissolved, and the mixture is stirred at a high speed for 30 minutes and mixed with non-water. An aqueous solvent dispersion was prepared. While stirring the toner dispersion in a water bath, the non-water-miscible solvent dispersion was added, and the mixture was stirred for 15 minutes and mixed. The resulting mixture was heated to 60 ° C. in 1 hour, the organic solvent was evaporated in 8 hours with stirring, and then cooled to 35 ° C. Next, washing with pure water by suction filtration was repeated 5 times, dried with a vacuum drier, crushed, and sieved with a 53 μm net to obtain toner particles. The average particle size of the obtained toner is 7.9 μm.
m and the number average fraction of particles having a particle size of 5 μm or less was 14.0%. When this was observed with a scanning electron microscope, it was observed that the toner was completely spherical. Rutile-type fine particle titanium oxide (specific surface area converted diameter: 20 mμm) was added to the original toner particles and the spherical toner particles by 0.5%.
%, The fluidity of the spherical toner was much better than the original toner. Further, these toner particles are mixed with an iron powder carrier having an average particle diameter of 100 μm to prepare a developer.
A stirring test in the developing machine was performed using a 039 developing machine (manufactured by Fuji Xerox Co., Ltd.). After stirring for 3 hours, in the original amorphous toner, the number average fraction having a particle size of 5 μm or less was increased to 33%, the toner was frequently fixed to the carrier, and the chargeability was reduced. On the other hand, in the case of the spherical toner, the number average fraction having a particle diameter of 5 μm or less was hardly changed at 14.5%, and the chargeability was slightly reduced.

Example 2 A treatment was carried out under the same composition and conditions as in Example 1 except that the amounts of methylene chloride and toluene were reduced to 1/3. The average particle size of the obtained toner was 7.7 μm, and the number average fraction having a particle size of 5 μm or less was 13.5%. When this was observed with a scanning electron microscope, it was observed that the toner was slightly deformed into a potato type. In this state, the fluidity of the deformed toner was not particularly changed as compared with the original toner. However, when the rutile-type fine particle titanium oxide (specific surface area converted diameter: 20 mμm) was added to the original toner and the spheroidized toner by 0.5% each, the fluidity of the deformed toner was lower than that of the original toner. It was pretty good. FX503
When a cleaning test was performed by a blade cleaning method using a 9-model developing machine (manufactured by Fuji Xerox Co., Ltd.), the deformed toner showed good cleaning performance as the original toner.

Example 3 85 parts by weight of styrene-n-butyl methacrylate resin (Mn = 9,000, Mw = 12,000, Tg = 62 ° C.) 10 parts by weight of carbon black (R330, manufactured by Cabot Corporation) Paraffin wax (melting point) 80 ° C.) 5 parts by weight The above composition was kneaded with a Banbury mixer, finely pulverized using a jet mill and classified, and the average particle size was 8.7 μm.
m, and toner particles having a number average fraction of 12.0% having a particle size of 5 μm or less were obtained. The shape of the obtained toner particles was observed with a scanning electron microscope, and it was confirmed that the particles had irregular shapes without regularity. Further, the exposure of wax on the toner surface could not be clearly observed. 200 parts by weight of the toner is dispersed in 1,500 parts by weight of water in which 0.05% by weight of ionic surfactant sodium lauryl sulfate is dissolved, and the mixture is stirred by a three-one motor for 30 minutes to obtain a uniform dispersion. Was. After dissolving 9.5 g of sodium phosphate in the above water, 3.7 g of calcium chloride is added to precipitate tricalcium phosphate in the toner-dispersed water, and the mixture is gently stirred for 5 minutes to remove the surface of the toner particles in the water. Attach tricalcium phosphate that partially aggregates to
A toner dispersion was prepared. Separately, 150 parts by weight of chloroform and 110 parts by weight of diethyl ether were added to 1,50 parts of water in which 0.05% by weight of sodium lauryl sulfate was dissolved.
The mixture was dispersed in 0 parts by weight and stirred at a high speed for 30 minutes to prepare a non-water-miscible solvent dispersion. While stirring the toner dispersion in a water bath, the non-water-miscible solvent dispersion was added, and 15
Stir for minutes and mix. The obtained mixture was heated to 70 ° C., and the organic solvent was evaporated for 8 hours while stirring.
After cooling to 35 ° C, 1N hydrochloric acid 200ml
Was added to maintain the acidity, and the precipitate of tricalcium phosphate was dissolved. Further, washing with pure water was repeated 5 times by suction filtration, dried with a vacuum drier, crushed, and sieved with a 53 μm net to obtain toner particles. The average particle size of the obtained toner was 9.0 μm, and the number average fraction of particles having a particle size of 5 μm or less was 10.4%. When this was observed with a scanning electron microscope, it was found that the toner was completely spherical and that fine concave portions were generated on the toner surface. Also, almost no paraffin wax was exposed on the surface of the toner. This toner and 80 μm diameter spherical ferrite coated with 0.8% by weight of polymethyl methacrylate were mixed for 20 minutes so that the toner concentration became 5% by weight. The spheroidized toner was good with little difference in chargeability compared to the original toner. Both the original toner and the spheroidized toner are each provided with a rutile type particulate titanium oxide (specific surface area converted diameter 20 m).
μm) was added by stirring with a mixer, and the fluidity of the spheroidized toner was much better than that of the original toner. When the adhesion state of titanium was observed with an electron microscope, many spherical toners were observed in which titanium was partially buried and adhered to concave portions on the toner surface. Apply both toners to the above FX
When a releasability test was conducted in the fixing step using a 5039 modified developing machine, the releasability of both toners was almost the same. Further, both toners are set in a state where the toner is recirculated by the same FX5039 remodeling type developing machine, and
When a copy test was carried out on 10,000 copies, in the case of the original toner, the chargeability was lowered and the image density was lowered. On the other hand, in the case of the spherical toner, the chargeability was hardly reduced, and good image quality was maintained.

Example 4 85 parts by weight of polystyrene-acrylic resin (Mn = 9,000, Mw = 12,000, Tg = 62 ° C.) 10 parts by weight of carbon black (R330, manufactured by Cabot Corporation) Paraffin wax (melting point: 74 ° C.) 5 parts by weight The above composition was kneaded with a Banbury mixer, finely pulverized using a jet mill, and classified to have an average particle size of 9.3.
μm, and toner particles having a particle diameter of 5 μm or less and a number average fraction of 15.0% were obtained. The shape of the obtained toner particles is
Observation with a scanning electron microscope confirmed that the sample had an irregular shape without regularity. Also, the exposure of the wax on the toner surface could not be clearly observed. 200 parts by weight of the toner is dispersed in 1,500 parts by weight of water in which 0.05% by weight of a nonionic surfactant polyoxyethylene nonylphenyl ether and 0.2% by weight of calcium carbonate are dissolved, and the three-way motor is used. And stirred for 30 minutes to obtain a toner dispersion. Separately, chloroform 310
Polystyrene (molecular weight Mn = 55,000, Mw = 100,000, Tg = 50 parts by weight and toluene
(100 ° C.) After dissolving 20 parts by weight,
The mixture was dispersed in 00 parts by weight and stirred at a high speed for 30 minutes to prepare a non-water-miscible solvent dispersion. While stirring the toner dispersion in a water bath, add the non-water-miscible solvent dispersion,
Stir for 15 minutes and mix. Thereafter, the temperature was raised to 70 ° C., and the organic solvent was evaporated for 8 hours while stirring. After cooling to 35 ° C., 1,000 ml of 1N hydrochloric acid was added.
In addition, it was kept acidic to dissolve the calcium carbonate precipitate. Further, washing with pure water by suction filtration was repeated 5 times, followed by drying with a vacuum drier, crushing, and sieving through a 53 μm net to obtain toner particles. The average particle size of the obtained toner is
9.5 μm, and the number average fraction of the particle size of 5 μm or less is 1
1.0%. When this was observed with a scanning electron microscope, the toner was completely spherical, and fine concave portions were observed on the toner surface, but almost no paraffin wax was exposed. When the cross section of the obtained toner was observed with a transmission electron microscope,
It was observed that a uniform film of polystyrene was formed around the polystyrene-acrylic resin, resulting in complete encapsulated particles. This toner and spherical ferrite having a diameter of 80 μm coated with 0.8% by weight of polymethyl methacrylate were mixed for 20 minutes so that the toner concentration became 5% by weight. This spheroidized toner is excellent in chargeability with almost no difference compared to the original toner, and inorganic fine particles such as silica are added to the toner surface compared to the original toner. The powder flowability was good even without this. This spherical toner was tested for fixability using the above-mentioned FX5039 modified type developing machine.
Good fixability was exhibited at low temperatures.

[0026]

According to the present invention, there is provided a method for producing a toner which is made spherical or deformed by a processing method using a specific particle dispersion and a specific non-water-miscible solvent dispersion. Since it swells, it is possible to produce various spherical electrostatic charge developing toners from a true sphere to a rounded amorphous one. The obtained toner for electrostatic charge development is excellent in fluidity with a narrow particle size distribution, has good developing properties, transfer properties, fixing properties and cleaning properties, and is used as a two-component developer. When used, it reduces the contamination of the carrier and the photoreceptor and retains stable chargeability for a long period of time, and when used as a one-component developer, reduces the contamination of the developing roller and the photoreceptor, and provides stable high image quality. Form an image. Further, the method for producing the toner of the present invention is a method for coating a resin having a high glass transition point by dissolving a resin having a high glass transition point in a non-water-miscible solvent used for sphering or deformation, without increasing the number of production steps. Encapsulated toner can be obtained simply and in good yield without increasing the particle size.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-52-9435 (JP, A) JP-A-55-69151 (JP, A) JP-A-4-307561 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) G03G 9/08

Claims (6)

(57) [Claims] 1. A step of forming fine particles of a composition comprising a binder resin and a colorant; a step of preparing the particle dispersion by dispersing the formed fine particles in an aqueous medium with a dispersant of a solid at room temperature; Preparing a non-water-miscible solvent dispersion by dispersing a hydrophobic solvent therein, mixing the particle dispersion and the non-water-miscible solvent dispersion, and heating and / or depressurizing the obtained mixture. And removing the hydrophobic solvent to form a spherical or deformable toner. 2. A step of forming fine particles of a composition comprising a binder resin, a colorant, and a release agent, and dispersing the formed fine particles in an aqueous medium with a room temperature solid dispersant to prepare a particle dispersion. Step, a step of preparing a non-water-miscible solvent dispersion by dispersing a hydrophobic solvent in an aqueous medium, a step of mixing the particle dispersion and the non-water-miscible solvent dispersion, and heating the resulting mixture and A method for producing a toner for electrostatic charge development, comprising a step of removing the hydrophobic solvent by reducing the pressure and / or making the toner spherical or deformed. 3. A step of forming fine particles of a composition comprising a binder resin and a colorant, and dispersing the formed fine particles in an aqueous medium with an inorganic fine particle dispersant generated in the aqueous medium. Preparing a liquid, dispersing a hydrophobic solvent in an aqueous medium to prepare a non-water-miscible solvent dispersion, mixing a particle dispersion and a non-water-miscible solvent dispersion, and mixing obtained. A method for producing a toner for electrostatic charge development, comprising a step of removing a hydrophobic solvent by heating and / or depressurizing a liquid to make it spherical or deformed. 4. A step of forming fine particles of a composition comprising a binder resin and a colorant, and dispersing the formed fine particles in an aqueous medium with an inorganic fine particle dispersant generated in the aqueous medium. A step of preparing a liquid, a step of dispersing a hydrophobic solvent in an aqueous medium to prepare a non-aqueous miscible solvent dispersion, a step of mixing a particle dispersion and a non-aqueous miscible solvent dispersion, and the obtained mixture. Having a step of removing hydrophobic solvent by heating and / or depressurizing to make the particles spherical or deformed, and a step of decomposing or dissolving inorganic fine particles on the toner particles. Manufacturing method. 5. A step of forming fine particles of a composition comprising a binder resin and a colorant, a step of preparing the particle dispersion by dispersing the formed particles in an aqueous medium with a room temperature solid dispersant, Dispersing a hydrophobic solvent in which the resin is dissolved, preparing a non-water-miscible solvent dispersion, mixing the particle dispersion and the non-water-miscible solvent dispersion, heating the resulting mixture and And / or removing the hydrophobic solvent by reducing the pressure to form encapsulated particles. 6. An electrostatic charge developing toner obtained by the method according to claim 1. Description: