JP2006322998A - Capsular toner and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capsular toner excellent in humidity dependence resistance without considerable restriction on materials of core particles used. <P>SOLUTION: Colored resin particles (A) having a volume average particle diameter of 3-10 μm are fluidized by a fluidizing gas, a spray liquid in which resin particles (B) are dispersed in a hydrophobic solvent is sprayed from spray nozzles 3 on the surface of the colored resin particles (A), and the solvent is evaporated by making the colored resin particles (A) ascend between a container 1 and a draft tube 7 to form the objective capsular toner having high hydrophobicity and excellent in humidity dependence resistance. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a capsule toner used for development of an image forming apparatus using an electrophotographic method, and a manufacturing method thereof.

  As a type of developing toner used in an image forming apparatus using an electrophotographic method, there are a dry method toner that does not use an aqueous medium and a wet method toner that uses an aqueous medium depending on the manufacturing method. In general, dry-type toner refers to pulverized toner, and powdered binder resin, colorant, charge control agent, and wax are mixed in a wind mixer such as a Henschel mixer, and the resulting mixed powder is mixed into a twin-screw kneader. The resin solid material obtained after cooling is pulverized to a few microns with a pulverizer such as a jet mill.

  Typical examples of the wet process toner include suspension polymerization toner and emulsion polymerization aggregation toner. For example, the suspension polymerization method toner is obtained by dispersing a polymerization initiator, a colorant, a charge control agent, a release agent, and the like in a vinyl monomer that is a raw material of a binder resin together with a dispersant in water using a stirrer such as a homogenizer. Manufactured through a process of suspension polymerization. For example, the emulsion polymerization aggregation toner is obtained by emulsion polymerization of a vinyl monomer as a raw material of a binder resin, and aggregating the obtained resin dispersion together with an aqueous colorant dispersion, an aqueous charge control agent dispersion, and an aqueous wax dispersion. Manufactured.

  In recent years, with the progress of colorization of image forming apparatuses using an electrophotographic system, there is a growing demand for color images at the level of gravure printing or photographic paper photographs even in images obtained by electrophotographic apparatuses. In order to achieve high image quality, development technology having high dot reproducibility without color unevenness and graininess is required along with high resolution and high image quality image processing technology of a scanner. In order to meet the demand, reduction of the toner particle size has become a major issue.

  In the pulverized toner, if it is attempted to reduce the particle size of the toner, the time and energy required for pulverization increase, and there is a demerit that the production amount decreases and the manufacturing cost increases. Further, the mixing rate of free wax and free charge control agent generated in the pulverization process tends to increase, and filming on the carrier and the photoconductor tends to occur, and the small particles whose toner has a volume average particle size of 6 μm or less. It is difficult to commercialize diameter toner.

  On the other hand, a polymerization toner is a technique suitable for reducing the particle size because fine toner particles can be directly produced by suspension polymerization or emulsion polymerization. However, in suspension polymerization or emulsion polymerization, monomers and resin fine particles are dispersed in an aqueous medium, so a highly hydrophilic dispersant or surfactant remains on the toner surface, and the charge amount and electrical resistance depend on humidity resistance. There is a problem that the nature is low.

  Although these highly hydrophilic materials can be removed to some extent by washing the toner particles, it is necessary to use a large amount of pure water in the washing step, and there is a problem that the manufacturing cost and the wastewater treatment cost increase. Furthermore, it is difficult to remove the dispersant and surfactant remaining in the vicinity of the toner surface without being exposed to the toner surface in the washing process, and the charging characteristics and electrical characteristics of the toner change over time depending on the dry state of the toner. There was a point.

  On the other hand, as a wet method toner other than the above-mentioned polymerization method, a method for producing an emulsion aggregation toner using a self-dispersing resin that can be dispersed in an aqueous medium without using a dispersant or a surfactant as a binder resin is disclosed in, for example, a patent. It is disclosed in Document 1 (JP-A-7-104509) and Patent Document 2 (JP-A-9-311502).

  According to the method described in Patent Document 1, an anionic self-dispersing polyester resin having sodium sulfonate or the like in the side chain is dispersed in an aqueous medium in the absence of a surfactant or the like, and the dispersed resin The toner particles are produced through a step of aggregating and associating the fine particles with the colorant aqueous dispersion to form toner particles, and then adding a divalent metal salt aqueous solution to exchange cations with divalent metal ions. Yes.

  No surfactant remains on the surface of the toner produced by this method, and the monovalent metal ions of the resin side chain are replaced with divalent metal ions, so that the hydrophobicity is improved. Is.

  However, even if the hydrophilicity is not as high as that of monovalent metal ions, it can not be said that the dependency on humidity resistance is sufficient because divalent metal ions having hydrophilicity are still present on the toner surface. Below, the resistance and charge amount of the toner are remarkably lowered, causing problems such as image fogging and transfer failure.

  According to the method described in Patent Document 2, after the self-dispersing resin having an ionic group such as carboxylic acid in the side chain is melt-kneaded together with the pigment, the obtained kneaded product is subjected to a temperature condition of 150 to 200 ° C. The toner particles are formed by being finely divided by stirring in an aqueous medium containing ammonia that neutralizes ionic groups. After the toner particles are formed, the surface of the toner particles is treated with dilute hydrochloric acid to convert the carboxylate on the toner surface into carboxylic acid, thereby improving hydrophobicity.

  However, although the hydrophilicity is not as high as that of the carboxylate, the carboxylic acid having hydrophilicity still exists on the toner surface, and the carboxylic acid is likely to be exposed on the toner surface due to the necessity of the manufacturing process using an aqueous medium. For this reason, it cannot be said that the humidity resistance dependency is sufficient, and there remains a problem with respect to environmental stability, such as the toner resistance and charge amount being significantly reduced in a high humidity environment, causing image fogging and transfer failure.

  Furthermore, the carboxylate that is not exposed on the toner surface remains in the vicinity of the toner surface without being converted to carboxylic acid, so adsorbed water tends to remain, and the charging characteristics and electrical characteristics of the toner change over time depending on the dry state of the toner. There was a problem such as.

JP 7-104509 A JP-A-9-311502

  As described above, there is a problem that it is difficult to further reduce the particle size of the toner in the dry method toner. Also, in the manufacturing method of the wet method toner capable of reducing the particle size as compared with the dry method toner, the moisture resistance is also reduced. Dependency issues remain.

  The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a capsule toner manufacturing method that forms a coating film having excellent humidity resistance dependency.

  Furthermore, an object of the present invention is to provide a capsule toner having excellent humidity resistance dependency.

  In the production method of the present invention for solving the above-described problems, a spray liquid in which resin particles (B) are dispersed in a hydrophobic solvent is applied to colored resin particles (A) circulated and fluidized with a fluidized gas. The capsule toner is manufactured by coating the surface of the colored resin particles (A) with the resin particles (B).

  Furthermore, the capsule toner for achieving the object of the present invention is applied with a spray liquid in which the resin particles (B) are dispersed in a hydrophobic solvent to the colored resin particles (A) circulated and fluidized with a fluidizing gas. By doing so, it is a capsule toner in which the surface of the colored resin particles (A) is coated with the resin particles (B).

  The production method of the present invention and the capsule toner obtained by the production method are not limited in the material of the core particles to be used, and are hydrophobic in which a highly hygroscopic surfactant is not present on the toner surface and in the vicinity of the toner surface. Since it has a high coating film, it becomes a toner excellent in humidity resistance dependency.

  As described below, the present invention is a capsule toner characterized in that the surface of the colored resin particles (A) is coated by applying a spray liquid composed of resin particles (B) dispersed in a hydrophobic solvent. And its manufacturing method. The following description will be divided into the manufacturing process of the capsule toner, the constituent materials for manufacturing the capsule toner, and the spray coating apparatus for encapsulation.

  FIG. 1 is a diagram showing a flow of a manufacturing process showing an example of manufacturing a capsule toner of the present invention. 1 shows a resin kneaded product manufacturing step S1, a core particle [colored resin particle (A)] manufacturing step S2, a washing / separating / drying step S3, a surfactant manufacturing step S4, and a spray liquid [resin particle (B)] manufacturing. This is an example of manufacturing the capsule toner through each step of step S5, spray coating step S6, and external addition step S7, and is of course not limited to the manufacturing step shown in FIG.

  First, in the resin kneaded product manufacturing step S1 in FIG. 1, a binder resin and a colorant, which are raw materials for the colored resin particles, and if necessary, a release agent and a charge control agent are mixed with a Henschel mixer, and then the mixture is mixed. It is melt-kneaded with a biaxial kneader to produce a colored resin kneaded product.

  Subsequently, in the core particle manufacturing step S2, the colored resin kneaded product obtained in the S1 step is put into an aqueous medium, and the colored resin particles (A) are granulated by stirring under high temperature and high pressure conditions.

  In the washing / separating / drying step S3, the colored resin particles (A) obtained in the step S2 are washed, separated and dried.

  In the surfactant production step S4, the colored resin particles (A) are coated with the resin particles (B) to produce a surfactant which is one component of the spray liquid for obtaining the capsule toner.

  In the spray liquid [resin particle (B) dispersion] production step S5, the resin particles in the hydrophobic solvent are obtained by performing a polymerization operation in the hydrophobic solvent using the surfactant obtained in the surfactant production step S4. A spray liquid in which (B) is dispersed is produced.

  In the spray coating step S6, using a fluidized bed spray coating apparatus, which will be described below as a specific example of the configuration, the surface of the colored resin particles (A) obtained in the cleaning / separation / drying step S3 is applied to the spray liquid manufacturing step S5. The spray liquid obtained in the above is applied to produce a capsule toner.

  In the external addition step S7, an external additive is added to and mixed with the capsule toner obtained in S6 to produce an externally added toner.

  The procedure for producing the capsule toner according to the present invention has been described above with reference to FIG. 1, and materials for producing the capsule toner will be described below.

<Core particles>
As the colored resin particles (A) used for the core particles of the present invention, (1) colored resin particles obtained by melting and kneading a colorant, a release agent, a charge control agent and the like together with a binder resin, (2) colored resin particles obtained by suspension polymerization of an aqueous suspension containing a monomer, a colorant, a release agent, and a charge control agent, and (3) resin fine particles dispersed in an aqueous medium, High-temperature and high-pressure combined particles obtained by agglomerating colorant fine particles, release agent fine particles, charge control agent fine particles, etc., and (4) a melt-kneaded product composed of resin, colorant, release agent, charge control agent, etc. Colored resin particles obtained by stirring in an aqueous medium can be used.

  The method for producing the colored resin particles (A) is not particularly limited, but affects the particle size controllability and production efficiency for small toner particles, the degree of freedom in selecting resin materials, and the uniformity of the coating film. Considering the smoothness of the surface that gives the colored resin particles obtained by stirring the melt-kneaded product comprising a resin or a colorant at a temperature higher than the softening point of the resin in the high-temperature and high-pressure aqueous medium of (4) above Is suitable.

  When the aqueous medium is heated to 100 ° C. or higher in the above method, it can be performed using an apparatus that can heat the aqueous medium while pressurizing it. As an apparatus that can be used, for example, a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), Claremix (manufactured by M Technique Co., Ltd.) or the like can be used.

  When the volume average particle size of the colored resin particles (A) is 3 μm or less, it is difficult to uniformly coat the coating particles, and when the particle size is 10 μm or more, the particle size of the obtained toner is large and it is difficult to obtain satisfactory image quality. Therefore, the volume average particle diameter of the colored resin particles (A) is suitably in the range of 3 to 10 μm. In particular, a volume average particle size of 3 μm to 6 μm is preferable in order to achieve the purpose of improving the image quality.

<Colorant>
As the colorant used for the colored resin particles (A), known colorants such as pigments and dyes such as yellow, cyan, magenta and black can be used.

  Examples of the colorant for yellow toner include C.I. I. Pigment Yellow 1, 3, 4, 5, 6, 12, 13, 14, 15, 16, 17, 18, 24, 55, 65, 73, 74, 81, 83, 87, 93, 94, 95, 97, 98, 100, 101, 104, 108, 109, 110, 113, 116, 117, 120, 123, 128, 129, 133, 138, 139, 147, 151, 153, 154, 155, 156, 168, 169, 170, 171, 172, 173, 180, 185 and the like. I. Pigment Yellow 17 (disazo), 74 (monoazo), 155 (condensed azo), and 180 (benzimidazolone).

  Examples of the colorant for magenta toner include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 17, 18, 22, 23, 31, 37, 38, 41, 42, 48: 1, 48: 2, 48: 3, 48: 4, 49: 1, 49: 2, 50: 1, 52: 1, 52: 2, 53: 1, 53: 3, 54, 57: 1, 58: 4, 60: 1, 63: 1, 63: 2, 64: 1, 65, 66, 67, 68, 81, 83, 88, 90, 90: 1, 112, 114, 115, 122, 123, 133, 144, 146, 147, 149, 150, 151, 166, 168, 170, 171, 172, 174, 175, 176, 177, 178, 179, 185, 187, 188, 189, 190, 193, 194, 202, 208, 209, 214, 216, 220, 221, 224, 242, 243, 243: 1, 245, 246, 247 and the like. I. Pigment Red 48: 1 (barium red), 48: 2 (calcium red), 48: 3 (strontium red), 48: 4 (manganese red), 53: 1 (lake red), 57: 1 (brilliant carmine), There are 122 (quinacridone magenta) and 209 (dichloroquinacridone red).

  As a colorant for cyan toner, phthalocyanine-based C.I. I. Pigment Blue 1, 2, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 15, 16, 17: 1, 27, 28, 29, 56, 60, 63, etc. In particular, C.I. I. Pigment Blue 15: 3 (phthalocyanine blue G), 15 (phthalocyanine blue R), 16 (metal-free phthalocyanine blue), and 60 (indanthrone blue).

  Carbon black produced by various methods can be used as the colorant for the black toner.

  One colorant may be used alone, or two or more colorants may be used in combination. Moreover, when using 2 or more types of coloring agents together, the coloring agent of the same color may be used together, and the coloring agent of the color of a several system | strain may be used together. The content of the colorant can be selected from a wide range according to the required toner characteristics, but is more preferably 0.1% by weight or more and 20% by weight or less with respect to 100% by weight of the resin. More preferably, they are 0.1 weight% or more and 15 weight% or less. If the amount is less than 0.1% by weight, it is difficult to obtain a sufficient image density. If the amount exceeds 20% by weight, the colorant tends to aggregate in the formed image.

  In order to obtain a toner having excellent transparency and color reproducibility, the number average particle diameter of the colorant dispersed in the resin is preferably 0.3 μm or less.

<Release agent>
In the toner of the present invention, the colored resin particles (A) can be used by containing a release agent. By including the release agent, a release effect on the fixing roller at the time of fixing can be provided.

  Known release agents can be used, for example, petroleum waxes such as paraffin wax and microcrystalline wax, carnauba wax, rice wax, candelilla wax, plant waxes such as wood wax, beeswax, spermaceti etc. Mineral waxes such as animal waxes, montan waxes, ozokerites, fats and oils synthetic waxes such as fatty acid amides and phenol fatty acid esters, low molecular weight polypropylene waxes, low molecular weight polyethylene waxes, hydrocarbon synthetic waxes such as Fischer-Tropsch wax, In addition, alcohol-based synthetic waxes and ester-based synthetic waxes can be used. These release agents may be used alone or in combination of two or more.

  In order to obtain a toner having excellent transparency and color reproducibility, the number average particle diameter of the release agent dispersed in the resin is preferably 0.3 μm or less.

<Charge control agent>
In the toner of the present invention, a charge control agent can be further contained in the colored resin particles (A). By adding a charge control agent to the toner of the present invention, the charging characteristics of the toner can be controlled.

  Examples of the charge control agent for controlling positive charge include organic compounds having a basic nitrogen atom, such as basic dyes, quaternary ammonium salts, aminopyrines, pyrimidine compounds, polynuclear polyamino compounds, aminosilanes, and nigrosine bases.

  Examples of the charge control agent for controlling the negative charge include oil-soluble dyes such as oil black and spiron black, metal-containing azo dyes, metal salts of naphthenic acid, metal salts of alkyl salicylic acid, fatty acid soaps, and resin acid soaps.

  The charge control agent is added in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the binder resin.

  In order to obtain a toner having excellent transparency and color reproducibility, the number average particle diameter of the charge control agent dispersed in the resin is preferably 0.3 μm or less.

  The colored resin particles (A) obtained by the method described above are coated with the spray liquid described below using the spray coating apparatus shown in FIG. 2 described later to produce the capsule toner of the present invention.

<Spray liquid>
In the present invention, a dispersion liquid in which resin particles (B) are dispersed in a hydrophobic solvent is used as a spray liquid, but a surfactant is used to disperse the resin particles (B) in the hydrophobic solvent. Can do. Although it does not restrict | limit especially as a manufacturing method of a spray liquid, For example, it can manufacture by the non-aqueous dispersion polymerization method and the melt emulsification method.

<Hydrophobic solvent>
As a hydrophobic solvent used as a medium for the spray liquid, the resin particles (B) can exist stably in the spray liquid, and after spraying the spray liquid onto the surface of the colored resin particles (A), the colored resin particles (A) Since it is required to evaporate without bleeding, it is preferable that the colored resin particles (A) and the resin particles (B) do not dissolve or swell the binder resins.

  As the hydrophobic solvent, a hydrocarbon solvent or an organic solvent having an SP value of 8.3 or less can be used. Specific examples include n-hexane, isohexane, cyclohexane, methylcyclohexane, ethylcyclohexane, n-heptane, n-octane, isooctane, ligroin, petroleum benzine, and mixtures thereof.

  In addition, if the boiling point of the hydrophobic solvent is too low, the solvent tends to evaporate from the spray liquid, causing problems such as clogging of the tip of the spray nozzle. Further, if the boiling point of the hydrophobic solvent is too high, there is a problem that the spray liquid does not evaporate quickly after spraying the surface of the colored resin particles (A), and the particles are aggregated. Is preferably in the range of 60 to 180 ° C.

<Surfactant>
In order to disperse the resin particles (B) in the hydrophobic solvent, a surfactant containing both a hydrophobic group (nonpolar group) and a polar group can be used, but a polar group having a very high hydrophilicity can be used. If it is contained or the ratio of the polar group to the hydrophobic group is high, the humidity resistance dependency of the capsule toner is lowered. Therefore, it is desirable to use a surfactant having an SP value in the range of 7 to 10. When a surfactant having an SP value of more than 10 is used, the moisture resistance dependency of the toner is reduced due to the hygroscopicity of the surfactant remaining on the surface of the capsule toner. With a surfactant having an SP value of less than 7, resin particles ( Since B) cannot be dispersed in a stable state, aggregates of resin particles (B) are generated, and uniform spray coating cannot be performed.

  The surfactant on the surface of the resin particle (B) dispersed in the hydrophobic solvent is such that the polar group side of the surfactant is oriented in the inner direction of the resin particle (B), and the hydrophobic group side of the surfactant is the resin. It arrange | positions so that it may orientate in the outer direction of particle | grains (B). For this reason, the surface of the capsule toner obtained by coating the resin particles (B) tends to expose the hydrophobic group side of the surfactant, and is inevitably a capsule toner that is hardly affected by humidity. There is a problem that the surfactant present in the substrate is detached and the carrier particles and the photoreceptor are contaminated.

  For the above problem, the polar group side of the surfactant is taken into the resin particles (B) by performing a polymerization reaction using a polymeric surfactant having an SP value in the range of 7 to 10. The surfactant can be prevented from detaching. Since only the hydrophobic group side is exposed on the obtained particle surface and the polar group side is taken into the resin particle, the humidity resistance dependency can also be improved.

  As a method for measuring the SP value (solubility parameter) in the present invention, the method of Sue, Clark (SUH, CLARKE) [J. P. S. A-1, 5, 1671-1681 (1967)] can be measured as follows.

  Weigh 0.5 g of the resin to be measured in a 100 ml beaker, add 10 ml of good solvent (dioxane, acetone) with a whole pipette, dissolve with a magnetic stirrer, and add hydrophobic solvent (n-hexane, ion-exchanged water) to this. Is added dropwise using a 50 ml burette, and the point at which the turbidity occurs at a measurement temperature of 20 ° C. is defined as the dropping amount.

From the above measured values, the SP value δ of the resin is the following formula:
δ = (V _ml ^1/2 δ _ml + V _mh ^1/2 δ _mh ) / (V _ml ^1/2 + V _mh ^1/2 )
[Wherein, V _ml is the molecular volume (ml / mol) of the solvent in the low SP solvent mixed system, V _mh is the molecular volume (ml / mol) of the solvent in the high SP solvent mixed system, and δ _ml Is the SP value of the solvent in the low SP solvent mixture system, and δ _mh is the SP value of the solvent in the high SP solvent mixture system. ].
here,
V _m = V ₁ V ₂ / (φ ₁ V ₂ + φ ₂ V ₁ )
δ _m = φ ₁ δ ₁ + φ ₂ δ ₂
[In the formula, V _m is the molecular volume (ml / mol) of the mixed solvent, V ₁ and V ₂ are the molecular volumes (ml / mol) of each solvent used, and φ ₁ and φ ₂ are The volume fraction of each solvent at the cloud point, δ _m is the SP value of the mixed solvent, and δ ₁ and δ ₂ are the SP values of each solvent. ].

<Resin particles (B)>
As the resin particles (B) used as the material for forming the coating film of the capsule toner, resin fine particles comprising a styrene resin or a polyester resin can be used. However, an acid value of 1 mgKOH can be imparted to the capsule toner with high hydrophobicity. / G or less of styrene resin is preferable.

  The number average particle diameter of the resin particles (B) is preferably in the range of 0.1 to 1 μm, more preferably 1 to 0.5 μm. If the number average particle diameter of the resin particles (B) exceeds 1 μm, the coating film becomes too thick or the resin particles (B) are detached from the surface of the colored resin particles (A), so that a uniform coating film cannot be formed. . Further, when the number average particle diameter of the resin particles (B) is less than 0.1 μm, the resin particles (B) are difficult to be fixed after spraying the spray liquid onto the surface of the colored resin particles (A), and the coating has a uniform film thickness. A film cannot be obtained.

  Although it does not restrict | limit especially as a manufacturing method of the resin particle (B) from which a number average particle diameter becomes 0.1-1 micrometer, For example, it can manufacture by the non-aqueous dispersion polymerization method, a melt emulsification method, etc.

  The glass transition point of the resin particles (B) can usually be from 45 ° C. to 75 ° C. However, by setting the glass transition point of the resin particles (A) 2 ° C. to 10 ° C. higher than the glass transition point of the colored resin particles (A), Preservability (cohesion resistance under high temperature environment) and low temperature fixability can be achieved well.

  At this time, if the coating film thickness is 0.1 μm or less, sufficient storage stability cannot be obtained. Conversely, if the coating film thickness is 1 μm or more, the low-temperature fixability is lowered, so the coating film thickness is in the range of 0.1 to 1 μm. Is preferred. The thickness of the coating film can be controlled by the particle diameters of the colored resin particles (A) and resin particles (B) to be mixed and the blending ratio of the colored resin particles (A) and resin particles (B). The coating film is not limited to one layer, and two or more types of resin particles having different glass transition points and softening points can be coated on two or more layers.

<External additive>
As described above, a known external additive can be added to the capsule toner of the present invention produced from various toner constituent materials for the purpose of improving fluidity and chargeability. Commonly used external additives include silica, titanium oxide, aluminum oxide having an average particle diameter of 0.007 μm to 0.02 μm, and surface treatment with silane coupling agent, titanium coupling agent, and silicone oil. The applied inorganic fine particles are used. In addition, since the surface of the toner obtained in the present invention is relatively smooth, a second external additive having an average particle size of 0.03 μm or more is used in combination for the purpose of improving transferability, cleaning properties and aggregation prevention. It is desirable. As the second external additive, for example, silica having an average particle size of 0.03 μm or more, titanium oxide, aluminum oxide, and inorganic that has been surface-treated with a silane coupling agent, a titanium coupling agent, and silicone oil. In addition to the fine particles, fatty acid metal salts, zinc stearate, calcium stearate, lead stearate, zinc oxide powder, vinylidene fluoride fine particles, and fluorine resin fine particles such as polytetrafluoroethylene fine particles.

  The amount of the external additive added is desirably in the range of 0.3 to 3 parts by weight with respect to 100 parts by weight of the toner body. If it is 0.3 parts by weight or less, the effect of improving the fluidity cannot be obtained, and if it is 3 parts by weight or more, the fixability is lowered.

  Further, abrasive fine particles can be added to the toner. Specific examples include fine abrasive particles such as strontium titanate, cerium oxide, silicon carbide, and magnetite. These fine particles may be treated with a coupling agent such as a silane coupling agent or a titanium coupling agent, silicone oil, or other organic compounds. Abrasive fine particles having a particle diameter in the range of 0.04 to 2 μm can be used. If the amount of the abrasive fine particles added is too large, the surface of the electrostatic latent image carrier and the developer carrier is rapidly worn, so that the amount added is preferably 2 parts by weight or less with respect to 100 parts by weight of the toner particles.

<Spray coating equipment>
The various constituent materials for producing the capsule toner according to the present invention have been described above. Next, as described above, the colored resin particles (A) containing at least the pigment as the colorant are prepared, and then the colored resin particles. (A) A coating apparatus for coating (coating) the resin particles (B) on the surface by spray coating will be described.

  FIG. 2 shows an example of this, and it is needless to say that the apparatus is not limited to this. That is, in this invention, what is necessary is just to apply | coat the spray liquid in which the resin particle (B) disperse | distributes to the colored resin particle (A) mentioned above, and can coat this resin particle (B).

  FIG. 2 is a schematic sectional view showing an example of a fluidized bed spray coating apparatus that can be used in the present invention. The apparatus includes a fluidized bed container 1 for circulating and flowing the colored resin particles (A) in a form that secures a space in which an upper portion 1a is formed in an inverted conical cylinder shape and a lower portion 1b is formed in a cylindrical shape on a mounting table. Is provided. This fluidized bed container 1 constitutes the exterior of the apparatus, and has a constricted shape 1d such that the upper side of the joint portion 1c between the inverted conical cylindrical upper portion 1a and the cylindrical lower portion 1b is narrowed inward. It is formed into a shape capable of circulating flow, which will be described later.

  In the uppermost part of the fluidized bed container 1, there is a filter device 2 for passing the circulating fluidized gas for fluidization formed in the fluidized bed container 1 and blocking the passage of the colored resin particles (A). The bottom plate 9 is provided in the lower part. The space between the bottom plate 9 and the filter device 2 is used to circulate and flow the fluidized gas.

  A mesh screen 6 formed in the shape of an inverted conical cylinder is provided on the top of the bottom plate 9 in the fluidized bed container 1, and the mesh screen 6 is divided into a space in the container to circulate and flow in the direction of the arrow. A cylindrical draft tube 7 is provided for forming the. The mesh screen 6 and the draft tube 7 are integrally formed and fixed in the fluidized bed container 1, for example, fixed to the bottom plate 9 or the fluidized bed container 1.

  An upper air passage 12 having a donut shape is formed between the outer wall of the draft tube 7 and the inner wall of the cylindrical fluidized bed container 1 to create an airflow rising in the arrow direction. The upper portion of the upper air passage 12 forms a shape 1d in which the fluidized bed container 1 is constricted so as to change the air flow toward the center of the fluidized bed container 1 in the vicinity of the joint portion 1c between the inverted conical cylinder and the cylinder. It is formed so as to be inclined upward.

  On the other hand, the central portions of the draft tube 7 and the mesh screen 6 are provided so that a rotary shaft 10 for rotating the first stirring blade 4 for forming a rotating airflow in the draft tube 7 passes therethrough. . The rotating shaft 10 is a rotating shaft of a drive source 11 such as a motor provided at the lower portion of the bottom plate 9 and penetrates the bottom plate 9 into the draft tube 7 in the fluidized bed container 1 through a bearing or the like. The first stirring blade 4 is fixed to the attachment member 4a. The plurality of first stirring blades 4 are rotatably provided with a gap 6a with respect to the surface of the mesh screen 6 having the inverted conical cylindrical shape, and impart an impact force to the colored resin particles (A) described later. It acts as an impact applying part.

  In addition, a plurality of second stirring blades 5 are fixed to the upper end of the rotating shaft 10 and are provided in a shape that allows the fluidized gas inside the draft tube 7 to flow downward when driven in rotation. ing.

  Further, a cylindrical housing for forming a fluidized gas suction passage is provided below the bottom plate 9. Therefore, a donut-shaped lower air passage 13 formed between the housing and the fluidized bed container 1 can be configured. The lower air passage 13 is used to supply a fluidized gas to the above-described space of the fluidized bed container 1, that is, the upper air passage 12 through an air supply fan (not shown). Corresponding to the air passage 13, a vent hole 8 for supplying fluidized gas into the fluidized bed container 1 through the air supply fan (not shown) is provided in the peripheral portion of the bottom plate 9. The fluidized gas passing through the vent hole 8 forms an ascending air current, and ascends the donut-shaped upper vent path 12 formed by the inner wall of the fluidized bed container 1 and the outer wall of the draft tube 7 as described above. In this case, the fluidized gas is preheated to a predetermined temperature and supplied as necessary.

  Here, a spray nozzle 3 for spraying a spray liquid composed of a spray liquid of resin particles (B) is provided in the fluidized bed container 1 in a region vented through the mesh screen 6 by the circulating flow of the fluidized gas. . The spray nozzle 3 is provided so that the two nozzles are separated from each other by 180 °. For example, the spray liquid is sprayed in a tangential direction with respect to a circular orbit of a horizontal rotating vortex generated by the rotation of the first stirring blade 4. Thus, it is attached to the fluidized bed container 1. Although not shown, the spray nozzle 3 is supplied in a mist form at a determined pressure from a supply unit that supplies a spray liquid.

  The fluidized bed container 1 has a structure that can be separated vertically at the joint portion 1c. By separating the fluidized bed container 1, the colored resin particles (A) can be introduced, the capsule toner can be taken out, and the disassembled and cleaned. It can be carried out.

  In the fluidized bed spray coating apparatus configured as described above, the fluidized gas passes through the vent holes 8 in the bottom plate 9 in the direction of the arrow and passes through the upper vent passage 12 in the fluidized bed container 1 by driving the air supply fan or the like. Create an airflow that rises toward the top. In addition, when the first stirring blade 4 and the second stirring blade 5 are rotated by driving the drive source 11, the fluidized gas in the draft tube 7 acts to vent the mesh screen 6. Due to this action, the inside of the draft tube 7 has a negative pressure, and the fluidized gas flow rising on the outer peripheral surface of the draft tube 7 is sucked into the draft tube 7.

  Accordingly, an air flow of fluidized gas that circulates and flows between the inside of the draft tube 7 and the outer peripheral portion is formed. If the colored resin particles (A) produced as described above are put into the fluidized bed container 1 by forming such a circulating flow, the colored resin particles ( A) is circulated.

  The circulating and flowing colored resin particles (A) reach the spray application region by passing through the mesh screen 6. In this region, since the spray liquid in which the resin particles (B) are dispersed in the hydrophobic solvent is sprayed from the spray nozzle 3, the spray liquid is applied to the surface of the colored resin particles (A), and the resin particles (B) Adhere to. The applied colored resin particles (A) rise in the upper air passage 12, and the solvent of the applied spray liquid evaporates.

  The circulating and flowing airflow is not a simple donut shape, but becomes a swirling swirl airflow under the influence of the rotation of the first stirring blade 4. For this reason, the colored resin particles (A) circulate in the air current and are uniformly distributed inside the container 1 so that uniform application is possible in spray application. Moreover, since the spray liquid is sprayed in the rotating tangential direction also in the spray nozzle 3, the spray liquid can be applied to the surface of the colored resin particles (A) more efficiently and uniformly.

  The colored resin particles (A) coated with the spray liquid rise to the upper end of the draft tube 7 and then are sent to the impact applying unit by the swirling flow descending the inside of the draft tube 7 on the swirling flow of the fluidized gas.

  A part of the colored resin particles (A) is carried to the filter device together with the fluidized gas. After being trapped by the filter device, the first stirring blade 4 and the mesh are moved by the falling due to its own weight and the swirling flow of the fluidized gas. It is sent to an impact applying unit comprising the screen 6.

  The colored resin particles (A) sent to the impact applying unit collide with the first stirring blade 4 on which the colored resin particles (A) to which the resin particles (B) are attached rotate. Further, the colored resin particles (A) to which the resin particles (B) accelerated by the collision are attached receive an impact force by the collision with the mesh screen 6.

  These impact forces cause mechanochemical immobilization between the resin particles (B) and the surface of the colored resin particles (A), and at the same time, aggregates in which the colored resin particles (A) adhere gently. The effect of crushing is obtained. By these mechanochemical effect and crushing effect, the colored resin particles (A) on which the resin particles (B) adhere to the surface do not aggregate together, and the coating film made of the resin particles (B) on the colored resin particles (A) surface. Is gradually formed.

  The colored resin particles (A) that have passed through the mesh screen 6 while riding the swirling flow of the fluidized gas from the impact applying unit are applied with the spray liquid in the spray liquid application region while being crushed.

  By continuously performing the circulation cycle as described above, it is possible to form a uniform coating film without agglomeration even on fine toner particles having a volume average particle diameter of 10 μm or less.

  Further, the toner produced by the method of the present invention can be heat-treated using hot air at 150 to 300 ° C. after coating the resin particles (B) on the surface of the colored resin particles (A). As a result, a capsule toner having a stronger coating film can be produced, and the capsule toner is difficult to peel off even when stirred for a long time in the developing tank. As an apparatus that can be used for the heat treatment, there is, for example, a sufusing system (manufactured by Nippon Pneumatic Co., Ltd.).

  Next, when the resin particles (B) are spray-coated on the colored resin particles (A) by the fluidized bed spray coating apparatus having the above configuration, various appropriate conditions and the like will be described in detail below.

  First, the spray nozzle 3 will be described. From the spray nozzle 3, a spray liquid in which resin fine particles (B) having a number average particle diameter of 0.1 to 1 μm are dispersed is sprayed. The spray nozzle 3 is in the form of a two-fluid nozzle, and mist is generated by using compressed gas as atomization energy. The compressed gas at this time is preferably about 30 Nl / min. Thereby, the surface of the colored resin particles (A) is covered with the spray liquid containing the resin particles (B) by the mist of the spray liquid sprayed from the spray nozzle 3.

  The colored resin particles (A) covered with the spray liquid are solvated by the fluidized gas supplied into the fluidized bed container 1 through the vent holes 8 during circulation, particularly when rising. Evaporates. At this time, if the temperature of the fluidized gas to be introduced is less than 50 ° C., the solvent adhering to the colored resin particles (A) to which the spray liquid has adhered cannot be sufficiently evaporated. Since the particles (A) are aggregated, the temperature of the fluidized gas to be introduced is desirably 50 to 90 ° C.

  Moreover, the evaporation rate of the solvent is also affected by the amount of the fluidized gas introduced into the fluidized bed container 1 through the vent hole 8 with respect to the spray amount of the spray liquid sprayed from the spray nozzle 3. If the amount of fluidized gas introduced into the fluidized bed container 1 per unit time is small, the absolute humidity in the fluidized bed container 1 increases, and as a result, the solvent adhering to the colored resin particles (A) evaporates. Becomes insufficient and aggregates are generated. Therefore, the introduction amount of the fluidized gas is desirably 1000 times or more, more desirably 10,000 times or more the spray amount of the spray liquid.

  When a flammable organic solvent is used as the hydrophobic solvent used in the spray liquid, oxygen contained in the fluidized gas is reduced as much as possible in order to ensure safety. Therefore, the oxygen concentration in the fluidized gas is preferably a fluidized gas having an oxygen concentration of less than 1%.

  Next, the first stirring blade 4 will be described. The impact imparting portion has a mechanochemical effect of fixing the resin particles (B) on the surface of the colored resin particles (A) and an effect of pulverizing the aggregate formed by gently adhering the colored resin particles (A) to each other. can get. As a rotation condition of the first stirring blade 4 for obtaining the effect, the peripheral speed of the first stirring blade 4 is preferably 3 to 20 m / sec. If it is less than 3 m / sec, not only a sufficient mechanochemical effect can be obtained, but also it becomes difficult to maintain the fluidity of the colored resin particles (A) and aggregation occurs. If it exceeds 20 m / sec, fusion to the mesh screen 6 and fusion of the colored resin particles occur due to frictional heat.

  In addition, with respect to the mesh screen 6 for allowing the colored resin particles (A) to pass through the spray liquid application region, the distribution of the colored resin particles (A) toward the spray liquid application region, etc., depending on the formation conditions of the holes provided. It depends. When the aperture ratio is less than 30%, the number of colored resin particles passing through the mesh screen is reduced, and the colored resin particles (A) are retained in the draft tube 7 to cause adverse effects such as the generation of aggregates. Therefore, the aperture ratio of the holes provided in the mesh screen 6 is desirably 30% or more.

  The size of the holes provided in the mesh screen 6 is preferably 0.1 to 3 mm. When the size of the pores is smaller than 0.1 mm, the colored resin particles (A) tend to aggregate and adhere to the mesh screen when passing, and when the size is larger than 3 mm, the colored resin particles (A) generated by collision when passing through the mesh screen. The crushing effect is reduced and aggregates are likely to be generated.

  Furthermore, the thickness of the mesh screen 6 is preferably 0.5 to 3 mm or less. Below 0.5 mm, the rotational vortex in the circumferential direction generated inside the mesh screen 6 by the rotation of the first stirring blade 4 has a great influence on the outside of the mesh screen 6. As a result, the colored resin particles (A) rotating in the horizontal direction together with the rotating vortex are biased toward the side wall in the fluidized bed container 1 by centrifugal force, and the colored resin particles (A) are easily welded to the side wall. If it exceeds 3 mm, the mesh screen is likely to be clogged.

  If the clearance between the first stirring blade 4 and the mesh screen 6 exceeds 5 mm, the number of repeated collisions between the first stirring blade 4 and the mesh screen 6 is reduced, and an impact force can be applied efficiently. When 0.1 mm or less, the aggregation of the colored resin particles (A) is likely to occur. Therefore, the gap is preferably 0.1 to 5 mm.

  In order to confirm that the toner of the present invention described above can achieve the object, an example will be described below. From the results of evaluating the toner obtained in this example, it can be confirmed that the object of the present invention can be achieved, and it is understood that the effect of the present invention is achieved and the gist of the present invention becomes clear.

[Example 1]
≪Production process S1 of resin kneaded material≫
After 100 parts of polyester resin (glass transition point (Tg) 62 ° C., softening point 130 ° C.), 5 parts of colorant (carbon black) and 5 parts of wax (polyethylene melting point 125 ° C.) are mixed and dispersed in a Henschel mixer for 3 minutes, Using an extruder (trade name, Nidicus MOS140-800, manufactured by Mitsui Mining Co., Ltd.), the mixture was melt kneaded and dispersed to prepare a colored resin kneaded product.

≪Core particle manufacturing process S2≫
A 20 wt% aqueous dispersion of a water-soluble polymer dispersant was prepared by mixing 100 parts of polyacrylic acid (weight average molecular weight 10,000) ammonium salt and 400 parts of water. Next, 400 parts of the adjusted 20% aqueous solution of polyacrylic acid ammonium salt, together with 100 parts of the colored resin kneaded material adjusted in the resin kneaded product production step S1, were combined with a pressure adjusting valve, a heating means, and a rotor stator type stirring means ( It was put into a metal container having a diameter of 30 mm) and stirred and mixed (8000 rpm) for 10 minutes while being heated and pressurized at 150 ° C. and 5 atm. Heating was then stopped and the mixture was cooled to 20 ° C. with stirring.

≪Washing / separation / drying process S3≫
Thereafter, ion-exchanged water was added to the mixture for washing. Washing is performed by mixing the mixture and ion-exchanged water, adjusting the solid content to 10% by adding the ion-exchanged water, and then stirring (300 rpm) for 30 minutes with a turbine-type stirring blade. The same washing operation was repeated until the conductivity of the supernatant liquid separated by centrifugation was 10 μS / cm or less. Thereafter, the synthetic resin particles in the mixture were separated by centrifugation and dried to obtain about 100 parts of synthetic resin particles. Using the Coulter Multisizer II (manufactured by Coulter, Inc.) and measuring the volume average particle diameter and coefficient of variation of the colored resin particles (A) using an aperture of 100 μm as the aperture, the particle size was 6.0 μm. The coefficient of variation was 21.

≪Surfactant production process S4≫
To a reaction vessel equipped with a stirrer, a thermometer, a nitrogen introduction tube, and a cooling tube was charged 150.0 parts of Toxsorbent (a petroleum mixed solvent manufactured by Shoei Chemical Co., Ltd.), and the temperature was raised to 120 ° C. under a nitrogen gas stream. Into this, 50 parts of styrene (ST), 15.0 parts of methyl methacrylate (MMA), 8.37 parts of lauryl methacrylate (LMA), 25 parts of normal butyl acrylate (NBA), V-501 (manufactured by Wako Pure Chemical Industries, Ltd.) A mixture of 2.5 parts of 4-4′azobiscyanovaleric acid) and 40 parts of Toxsorbent was added dropwise over 3 hours and held at the same temperature for 1 hour, and then V-5010.15 parts and Toxsorbent 10 Part of the solution was added dropwise over 15 minutes, and the solution was kept at the same temperature for 5 hours. After the temperature was lowered to 80 ° C., 1.63 parts of glycidyl methacrylate and 0.2 parts of 1,8-diazabicyclo [5,4,0] undecene were added and reacted for 2 hours. Thereafter, the mixture was cooled to obtain a solution of a long-chain macromonomer having a radical polymerizable group at the molecular end.

  While maintaining this solution at 95 ° C., 60 parts of styrene (ST), 10 parts of methacrylic acid (MA), 30 parts of normal butyl acrylate (NBA) and Kayaester O (N-kasei t-butylperoxy 2-ethyl) A mixture of 1.0 part of hexanoate and 1.0 part of Toxosolvent was added dropwise over 3 hours and held at the same temperature for 1 hour, followed by a solution of 0.25 part of Kayaester O and 2.33 parts of Toxsorbent. Was added dropwise over 30 minutes. Further, the mixture was kept at the same temperature for 1.5 hours and then cooled to obtain a surfactant solution (P) having a nonvolatile content of 50.4%, Mn = 3200, Mw = 28000, and SP = 9.1.

≪Spray production process S5≫
In a reaction vessel equipped with a stirrer, a thermometer, a nitrogen introduction tube, and a cooling tube, 39.7 parts of the surfactant solution (P) obtained in the above step S4 and Isopar G (manufactured by Esso Standard Petroleum) 360. 3 parts were charged and the temperature was raised to 110 ° C. MMA 48.0 parts, ethyl acrylate (EA) 20.0 parts, ST11.8 parts, divinylbenzene 0.2 part, Kayaester O 1.0 part mixed liquid was dropped into this over 2 hours, After holding at the same temperature for 2 hours, 0.25 parts of Kayaester O was added and kept at the same temperature for 2 hours. After cooling, the mixture was diluted with 33.33 parts of Toxsorbent, the non-volatile content was 19.8%, the particle size was 0. A spray liquid in which 42 μm resin particles (B) were dispersed was obtained. The resin particles (B) had a Tg of 61 ° C.

≪Spray coating process S6≫
600 g of the colored resin particles (A) obtained in the above step S3 were charged into the container of the fluidized bed coating apparatus shown in FIG. On the other hand, the spray liquid in which the resin particles (B) obtained above were dispersed was set in a spray charging container composed of a two-fluid nozzle. Using nitrogen gas having an oxygen concentration of less than 1% as the fluidizing gas, the supply temperature is set to 80 ° C., the supply air volume is set to 0.5 m ³ / min, and the peripheral speed of the first stirring blade 4 is set to 11 m / sec. The solution was sprayed with a total of 303 g (solid content concentration: 60 g) at a speed of 5 g / min. After spraying, the mixture was stirred for 15 minutes, and the capsule toner was taken out of the container.

  When the obtained capsule toner was observed with a scanning electron microscope (SEM), it was found that a plurality of capsule toner particles adhered to each other and no coarse particles such as aggregates were formed, and the surface was smooth and spherical. Only capsule toner was observed. The obtained capsule toner had a volume average particle size of 6.2 μm, a coefficient of variation of 22, and a circularity of 0.97.

≪External addition process S7≫
To 100 parts of the capsule toner, 0.7 parts of silica particles hydrophobized with a silane coupling agent having an average primary particle size of 20 nm were mixed with a Henschel mixer to obtain an externally added toner (T-1). .

<Production of developer>
The externally added toner (T-1) was mixed with a silicon-coated ferrite carrier having an average particle diameter of 50 μm with a ball mill to prepare a two-component developer (D-1) having a toner concentration of 7%.

[Example 2]
Instead of the surfactant solution (P) used in Example 1, a surfactant solution (Q) prepared by the following method was prepared.

[Preparation of surfactant solution (Q)]
While maintaining the solution of the long-chain macromonomer prepared in the same manner as in Example 1 at 95 ° C., 60 parts of styrene (ST), 10 parts of methacrylic acid (MA), 23 parts of normal butyl acrylate (NBA), A mixture of 7 parts of hydroxyethyl methacrylate (HEMA), 1.0 part of Kayaester O (Nippon Kayaku t-butylperoxy 2-ethylhexanoate) and 1.0 part of Toxsorbent was added dropwise over 3 hours. After maintaining at the same temperature for a time, a solution of 0.25 parts of Kayaester O and 2.33 parts of Toxsorbent was added dropwise over 30 minutes. Furthermore, after maintaining at the same temperature for 1.5 hours, it cooled and obtained surfactant solution (Q) of Mn = 3500, Mw = 31000, SP = 9.8.

  Using the surfactant solution (Q), the toner of Example 2 was produced in the same manner as in Example 1. When the obtained toner was observed with a scanning electron microscope (SEM), it was found that a plurality of capsule toner particles adhered and no coarse particles such as aggregates were formed, and the surface was smooth and spherical. Only toner was observed. The obtained capsule toner had a volume average particle size of 6.2 μm, a coefficient of variation of 23, and a circularity of 0.98. The particle size of the resin particles (B) contained in the hydrophobic solvent used as the spray liquid was 0.48 μm.

  From the capsule toner obtained above, externally added toner (T-2) and developer (D-2) were produced in the same manner as in Example 1.

[Example 3]
Instead of the surfactant solution (P) used in Example 1, a surfactant solution (R) prepared by the following method was prepared.

[Preparation of surfactant solution (R)]
While maintaining the solution of the long-chain macromonomer prepared in the same manner as in Example 1 at 95 ° C., 55 parts of styrene (ST), 10 parts of methacrylic acid (MA), 25 parts of normal butyl acrylate (NBA), A mixture of 10 parts of lauryl methacrylate (LMA), 1.0 part of Kayaester O (Nippon Kayaku t-butylperoxy 2-ethylhexanoate) and 1.0 part of Toxsorbent was added dropwise over 3 hours, and 1 hour. After maintaining at the same temperature, a solution of 0.25 parts of Kayaester O and 2.33 parts of Toxsorbent was added dropwise over 30 minutes. Furthermore, after maintaining at the same temperature for 1.5 hours, the mixture was cooled to obtain a surfactant solution (R) having Mn = 3300, Mw = 30000, and SP = 8.9.

  Using the surfactant solution (R), the toner of Example 3 was produced in the same manner as in Example 1. When the obtained toner was observed with a scanning electron microscope (SEM), it was found that a plurality of capsule toner particles adhered to each other did not contain coarse particles that formed aggregates, and the surface was smooth and spherical capsules. Only toner was observed. The obtained capsule toner had a volume average particle size of 6.2 μm, a coefficient of variation of 23, and a circularity of 0.97. The particle diameter of the resin particles (B) contained in the hydrophobic solvent used as the spray liquid was 0.39 μm.

  From the capsule toner obtained above, externally added toner (T-3) and developer (D-3) were produced in the same manner as in Example 1.

[Comparative Example 1]
Using the colored resin particles (A) produced in Example 1, the externally added toner (T-4) and the developer (D-4) are produced in the same manner as in Example 1 without performing the spray coating step S6. Was made.

[Comparative Example 2]
Instead of the surfactant solution (P) used in Example 1, a surfactant solution (S) prepared by the following method was prepared.

[Preparation of surfactant solution (S)]
While maintaining the solution of the long-chain macromonomer prepared in the same manner as in Example 1 at 95 ° C., 60 parts of styrene (ST), 10 parts of methacrylic acid (MA), 20 parts of normal butyl acrylate (NBA), A mixture of 10 parts of methoxytriethylene glycol acrylate, 1.0 part of Kayaester O (Nippon Kayaku t-butylperoxy 2-ethylhexanoate) and 1.0 part of Toxsorbent was added dropwise over 3 hours, and 1 hour. After maintaining at the same temperature, a solution of 0.25 parts of Kayaester O and 2.33 parts of Toxsorbent was added dropwise over 30 minutes. Furthermore, after maintaining at the same temperature for 1.5 hours, it cooled and obtained surfactant solution (S) of Mn = 3400, Mw = 28000, SP = 10.6.

  A toner of Comparative Example 2 was prepared in the same manner as in Example 1 using the surfactant solution (S). When the obtained toner was observed with a scanning electron microscope (SEM), it was found that a plurality of capsule toner particles adhered to each other did not contain coarse particles that formed aggregates, and the surface was smooth and spherical capsules. Only toner was observed. The obtained capsule toner had a volume average particle size of 6.2 μm, a coefficient of variation of 23, and a circularity of 0.97. The particle diameter of the resin particles (B) contained in the hydrophobic solvent used as the spray liquid was 0.36 μm.

  From the capsule toner obtained above, externally added toner (T-5) and developer (D-5) were prepared in the same manner as in Example 1.

<Evaluation results>
Each developer produced in the above Examples and Comparative Examples was evaluated for humidity resistance dependency. As evaluation items, image quality and transferability in a high temperature and high humidity environment (35 ° C., humidity 80%) and in a low temperature and low humidity environment (10 ° C., humidity 25%) were evaluated.

As a machine for evaluation, a digital full-color composite machine (manufactured by Sharp Corporation: AR-C150) was used, and the toner adhesion amount on the solid image portion on the photosensitive drum was measured under normal temperature and normal humidity (20 ° C., humidity 60%). Each developer was evaluated under development conditions of 0.5 mg / cm ² .

(Image quality evaluation)
As image quality evaluation items, the image density and fog density in each environment of high temperature and high humidity environment (HH) and low temperature and low humidity environment (LL) were measured. As an image quality evaluation standard, a developer satisfying both conditions of an image density of 1.4 or more and a fog density of 1.0 or less was rated as ◯, and a developer not satisfying either one was marked as x.

  The image density is measured using a spectrocolorimetric densitometer (manufactured by Nippon Planographic Printing Equipment Co., Ltd .: X-Rite 938), and the fog density is measured by a whiteness meter (manufactured by Nippon Denshoku Industries Co., Ltd .: Z-Σ90 COLOR MEASURING SYSTEM). Was calculated according to the following procedure.

The whiteness of A4 size full color dedicated paper (manufactured by Sharp Corporation: PP106A4C) is measured in advance, and the value is defined as a first measured value W1. Next, three originals including a white circle with a diameter of 55 mm are copied, and the whiteness of the obtained white portion is measured with a whiteness meter, and this value is set as a second measurement value W2. The fog density W (%) was calculated from the following formula.
W = {100 × (W1-W2) / W1}

(Transferability evaluation)
As a transferability evaluation item, transferability in each environment of high temperature and high humidity environment (HH) and low temperature and low humidity environment (LL) was measured. As a transferability evaluation standard, a developer having a transfer efficiency of 95% or more was evaluated as ◯, and a developer having a transfer efficiency of less than that was evaluated as ×.
Table 1 shows the evaluation results of each developer.

  As is apparent from the evaluation results in Table 1, the capsule toners obtained in Examples 1 to 3 have image quality and transferability in high temperature and high humidity environments (HH) and low temperature and low humidity environments (LL). Was good and showed good humidity dependency.

FIG. 5 is a process diagram showing an example of a method for producing a capsule toner according to the present invention and showing a series of flows according to the method for producing a toner. It is sectional drawing which shows an example of the fluidized bed spray coating apparatus used for the manufacturing method of the capsule toner in this invention.

Explanation of symbols

S5 Spray liquid production process S6 Spray coating process 1 Fluidized bed container 3 Spray nozzle 4 First stirring blade 6 Mesh screen 7 Draft tube

Claims (11)

  The surface of the colored resin particles (A) is obtained by applying a spray liquid in which the resin particles (B) are dispersed in a hydrophobic solvent in a sprayed state to the colored resin particles (A) circulated and fluidized with a fluidized gas. A method for producing a capsule toner, comprising coating resin particles (B) on the surface.   2. A method for producing a capsule toner according to claim 1, wherein a spray liquid containing a surfactant having an SP value of 7 to 10 is applied in a hydrophobic solvent.   After applying the impact force to the colored resin particles (A) to fix the resin particles (B) adhering to the surface, the colored resin particles (A) are circulated to the area where the sprayed dispersion is applied. The method for producing a capsule toner according to claim 1, wherein the capsule toner is fluidized.   The colored resin particles (A) are circulated in the air passage formed by the container and the draft tube provided in the container together with the fluidized gas, and the colored resin particles (A) at a portion flowing from the inside of the draft tube to the air passage. 4. The method for producing a capsule toner according to claim 3, wherein an impact force is applied to the toner.   The capsule toner manufacturing method according to claim 4, wherein the impact force applied to the colored resin particles (A) is given by the rotational energy of a stirring blade installed in a draft tube.   6. The capsule toner manufacturing method according to claim 4, wherein the stirring blade has a peripheral speed of 3 to 20 m / sec.   7. A method for producing a capsule toner according to claim 4, wherein fluidized gas at 50 to 90 [deg.] C. is introduced from the bottom of the container.   8. The capsule toner manufacturing method according to claim 7, wherein the fluidized gas has an oxygen concentration of less than 1%.   9. The volume average particle diameter of the colored resin particles (A) is 3 to 10 [mu] m, and the number average particle diameter of the resin particles (B) is 0.1 to 1 [mu] m. Manufacturing method for capsule toner.   A method for producing a capsule toner, wherein the capsule toner obtained by the production method according to claim 1 is further heat-treated using hot air at 150 to 300 ° C.   The capsule toner obtained by the manufacturing method in any one of Claims 1-10.

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