JP2006322997A - Capsulized toner and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide high-productivity granular toner which has a small diameter, substantially leaving no organic solvent and excellent in moisture resistance. <P>SOLUTION: An aqueous dispersion liquid including pigmented resin particles (A) 2-10 μm in number average diameter and an aqueous dispersion liquid including resin particles (B) 0.3 μm or smaller in number average diameter containing styrene resin having carboxylate in the side chain are mixed together in a covering step S4, and further, the resin particles (B) are flocculated on the surfaces of the above pigmented resin particles (A). Then the carboxylate on the side chain is transformed into carboxylic acid by adding acid during or after the above flocculation. Processing in the following filtering and washing step S5 and drying step S6, excellent capsulated toner can be obtained with high moisture resistance and productivity although small in diameter. <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 system and a method for manufacturing the same.

  As a type of 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. 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. As a typical wet process toner, there is a polymerization process toner, which is manufactured through a process of directly forming toner particles in an aqueous medium.

  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, it is an essential task to reduce the particle size of the toner.

  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. Moreover, free wax and free charge control agent are more likely to be generated in the pulverization step as the particle size is reduced. When the mixing ratio of free wax, free charge control agent, etc. in the toner increases, filming on the carrier and the photoreceptor tends to occur easily. As a result, it is difficult to commercialize a small-diameter toner having a toner volume average particle diameter of 6 μm or less.

  On the other hand, as a polymerization method toner, for example, a polymerization initiator, a colorant, a charge control agent, a release agent and the like are dispersed in water using a homogenizer or the like in a vinyl monomer which is a raw material of a binder resin and suspended. Suspension polymerization toner produced through the step of turbid polymerization, and emulsion polymerization of vinyl monomer that is a raw material for the binder resin, and the resulting latex is used as an aqueous colorant dispersion, an aqueous charge control agent dispersion, and an aqueous wax dispersion. In general, an emulsion polymerization aggregation toner produced through a coagulation step is known.

  Since these polymerized toners can directly produce fine toner particles in an aqueous medium, a step of pulverizing the resin is unnecessary, and it is considered to be a technique suitable for reducing the particle size. However, it is difficult to control dispersion of a release agent or a colorant, and there is a problem that color reproducibility of a color image formed using this toner is inferior. On the other hand, in the emulsion polymerization aggregation method, since it is necessary to use a large amount of a highly hydrophilic surfactant, there remains a problem that the resulting toner has poor moisture resistance (high humidity dependency).

  Further, as a wet method toner other than the polymerization method, an emulsion aggregation method toner using a self-dispersing resin that does not require the use of a surfactant is disclosed in, for example, Patent Document 1 (Japanese Patent Laid-Open No. 5-66600) and Patent Document 2. (Japanese Unexamined Patent Publication No. 7-104509).

  According to the method for producing a toner described in Patent Document 1, a mixture obtained by mixing a styrene resin having a carboxylate dispersible in an aqueous medium together with a colorant in an organic solvent without using a surfactant or the like. Toner is produced by phase inversion emulsification by dropping water into the toner.

  Further, according to the method for producing a toner described in Patent Document 2, a polyester resin having a sulfonate or a carboxylate that can be dispersed in an aqueous medium without using a surfactant or the like is used together with a colorant and an organic solvent. Water is dropped into the mixture mixed therein to perform phase inversion emulsification to form colored resin fine particles, and then the formed colored resin fine particles are aggregated to produce a toner.

  However, in the toners described in Patent Documents 1 and 2, the organic solvent used in the phase inversion emulsification step is removed by vacuum distillation after the toner particles are formed. In this method, the organic solvent is contained in the toner. It is difficult to completely remove the toner, and there is a problem that the toner tends to aggregate when the toner is stored for a long period of time. In addition, it takes a considerable amount of time and heat to remove the organic solvent in the toner manufacturing process, resulting in high manufacturing costs, and wastewater treatment costs are high because the organic solvent is contained in the wastewater. It was.

  As wet toners that do not use an organic solvent, for example, Patent Document 3 (Japanese Patent Laid-Open No. 9-31502), Patent Document 4 (Japanese Patent Laid-Open No. 10-39545), and Patent Document 5 (Japanese Patent Laid-Open No. 2002-351140). ).

  According to the method described in Patent Document 3, a colored resin kneaded product obtained by melt-kneading a polyester resin that can be self-dispersed in an aqueous medium and a colorant, and an aqueous medium containing 150 ° C. to 200 ° C. containing ammonia under pressure. The toner is manufactured by stirring and making fine particles therein.

  However, although the toner particles can be produced without using an organic solvent in the above production method, in order to make the colored resin kneaded material fine particles in an aqueous medium, the softening point of the resin and the melting point of the release agent There is a problem that it is necessary to perform a dispersion treatment at a higher temperature, and a release agent that easily bleeds is released from the binder resin, or the release agents are aggregated.

  According to the method described in Patent Document 4, after mixing an aqueous dispersion of a polyester resin having a sulfonate and an aqueous dispersion of a colorant, toner particles are formed by adding magnesium chloride to cause aggregation. ing.

  According to Patent Document 5, a kneaded product obtained by melting and kneading a polyester resin containing a carboxylate and a colorant is finely dispersed without using a surfactant in an aqueous medium containing a basic neutralizing agent. Then, toner particles are formed by agglomeration.

  However, in the toners described in Patent Document 4 and Patent Document 5, although toner particles can be granulated without using a surfactant, highly hydrophilic sulfonates and carboxylates remain on the toner surface. For this reason, there is a drawback that the charge amount and insulation properties decrease under high temperature and high humidity conditions, and further improvement in moisture resistance is desired.

JP-A-5-66600 JP 7-104509 A JP-A-9-311502 JP-A-10-39545 JP 2002-351140 A

  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, and also in the manufacturing method of the wet method toner capable of reducing the particle size as compared with the dry method toner, There was a problem like this. That is, there are problems peculiar to a wet process toner such as the remaining organic solvent, the remaining surfactant or sulfonium ion group which lowers the hydrophobicity, or the release of the release agent.

The present invention has been made in order to solve the above-described problems of the prior art. There is substantially no remaining organic solvent, high productivity in a small particle size toner, and excellent moisture resistance.
Another object of the present invention is to provide a toner having high low-temperature fixability and high hot offset resistance.

  The toner of the present invention for solving the above-mentioned problems is a resin particle (B) composed of a styrene resin having a carboxylate in the side chain on the colored resin particles (A) containing at least a colorant. This is a capsule toner in which the carboxylate in the side chain of the resin particle (B) is converted to carboxylic acid.

  Further, the toner of the present invention for solving the above-mentioned problems is obtained by adding ammonia to a colored resin particle (A) containing a colorant and having a carboxylic acid in the side chain and an acid value of 0.1 to 10 mgKOH. Alternatively, it is a capsule toner in which resin particles (B) obtained by dispersion treatment in an aqueous medium containing an alkali metal hydroxide are agglomerated and coated, and the carboxylate of the resin particles (B) is converted to carboxylic acid.

  The production method for achieving the object of the present invention comprises an aqueous dispersion of colored resin particles (A) containing at least a colorant and styrene resin particles (B) having a carboxylate in the side chain. An aqueous dispersion is mixed, a flocculant is added to the obtained liquid mixture, and the resin particles (B) are agglomerated and coated on the surface of the colored resin particles (A), and then an acid is added to produce a capsule toner. It is characterized by.

  In the capsule toner and the method for producing the same of the present invention, fine toner particles can be formed without the pulverization step when forming the toner particles or the organic solvent removal step after the toner particles are formed. Since the surface of the particles is substantially free of surfactants and dispersants and has a coating layer made of a styrene resin with a low acid value, it is highly productive and moisture resistant even for small-diameter toners. The capsule toner is excellent (low humidity dependency such as charge amount).

  Furthermore, by optimizing the physical properties of the coating material, the toner is excellent in storage stability (aggregation resistance under high temperature environment), fluidity, and fixing properties.

  The present invention is a toner according to a wet method, and is a capsule toner in which a colored resin particle (A) is coated with a resin material (B) as described below. Hereinafter, the toner production method and the constituent materials for constituting the toner will be described separately.

  FIG. 1 is a diagram showing a flow of a manufacturing process showing an example of manufacturing a capsule toner of the present invention. FIG. 1 shows an aqueous dispersion production step S1, an aqueous dispersion mixing step S2, a core particle [colored resin particle (A)] production step S3, a shell material [resin particle (B)] coating step S4, a filtration washing step S5, This is an example of producing a capsule toner through each of the drying step S6 and the external addition step S7, and it goes without saying that the production of the toner is not limited to the one described below.

  First, in the mixed liquid preparation step S1 of FIG. 1, an aqueous dispersion is prepared by dispersing a self-dispersing resin, a colorant, a release agent, and a charge control agent in water.

  Next, in the aqueous dispersion mixing step S2, an aqueous dispersion composed of the self-dispersing resin, the colorant, the release agent, and the charge control agent adjusted in the mixed liquid adjusting step S1 is mixed to adjust the mixed solution.

  Subsequently, in the particle forming step S3, an aggregating agent is added to the aqueous dispersion mixture prepared in the aqueous dispersion mixing step S2, and the core particles that are the colorant resin (A) in the present invention described in detail below are aggregated. Make a thing. Furthermore, the aqueous dispersion of core particles composed of aggregates having a uniform shape is prepared by heating the aqueous medium to the glass transition point of the self-dispersing resin.

  On the other hand, in the shell material covering step S4, the core particle aqueous dispersion prepared in the particle forming step S3 and the self-dispersing resin which is the resin particle (B) having a carboxylate according to the present invention described in detail below. The aqueous dispersion is mixed, and a flocculant is added to form agglomerated coated particles coated with the shell material. Further, the toner body particle precipitate in the present invention is formed by forming an aggregate having a uniform shape by heating the aqueous medium to the glass transition point of the self-dispersing resin and then hydrophobizing it by adding dilute hydrochloric acid. make.

  It is necessary to take out toner main body particles, which are aggregated coated particles formed in the shell material coating step S4. Therefore, in the next filtration and washing step S5, the toner main body particles are washed with pure water after removing the filtrate by filtering the toner main body particles. Cleaning of toner using pure water is performed to remove unnecessary components other than toner components such as impurities that affect the chargeability of the toner, but the cleaning method is performed in a batch manner. Alternatively, it may be performed continuously. Further, the toner is preferably washed until the conductivity of the supernatant is 50 μS / cm or less.

  After passing through the above steps, next, in a drying step S6, the toner main body particles are dried under reduced pressure conditions. Thereby, the capsule toner in the present invention can be obtained.

  For example, an external additive is added to the capsule toner manufactured as described above in order to improve fluidity as necessary. For this purpose, in the external addition step S7, the toner main body particles and the external additive are mixed using an air stirrer such as a Henschel mixer to produce an externally added toner. Further, since the toner particles obtained in the drying step S6 form a gentle aggregate, it is desirable that the toner particles be pulverized in advance with a Henschel mixer or the like.

  Since the toner production method of the present invention has substantially no hydrophilic substance such as a surfactant or hydrophilic group such as a carboxylate on the toner surface, a capsule toner excellent in moisture resistance can be produced.

  As the stirrer in the toner production method of the present invention, known emulsifiers and dispersers can be used. Specifically, Ultra Turrax (trade name: manufactured by IKA Japan Co., Ltd.), Polytron homogenizer (trade name: manufactured by Kinematica Co., Ltd.) and TK Auto Homo Mixer (trade name: manufactured by Tokushu Kika Kogyo Co., Ltd.) Batch type emulsifier, Ebara Milder (trade name: manufactured by Ebara Manufacturing Co., Ltd.), TK Pipeline Homomixer (trade name: manufactured by Tokushu Kika Kogyo Co., Ltd.), TK Homomic Line Flow (trade name: Special Machine) Chemical Industry Co., Ltd.), Fillmix (trade name: Special Machine Chemical Industry Co., Ltd.), colloid mill (trade name: Shinko Pantech Co., Ltd.), Thrasher (trade name: Mitsui Miike Chemical Industries, Ltd.) ), Trigonal wet milling machine (trade name: manufactured by Mitsui Miike Chemical Co., Ltd.), Cavitron (trade name: manufactured by Eurotech Co., Ltd.) and Fine Flow Mill (trade name: Taiheiyo Kiko Co., Ltd.) ) Continuous emulsification machine such as, Claire mix: manufactured (trade name M Technique Co., Ltd.) and fill mix: manufactured (trade name Kika Kogyo Co., Ltd.), and the like. The emulsifier and the disperser preferably have a heat retaining means.

  The toner manufacturing method of the present invention has been described above, but the constituent materials of the toner for use in the manufacturing method will be described below.

<Aqueous dispersion of colored resin particles (A)>
As an aqueous dispersion of colored resin particles (A) containing a colorant, an aqueous dispersion in which aggregated particles obtained by aggregating a resin or a colorant from an aqueous dispersion obtained by dispersing a resin or a colorant is dispersed. An aqueous dispersion obtained by polymerizing a liquid or an aqueous suspension containing a colorant and a monomer can be used.

  Further, regarding the number average particle diameter of the colored resin particles (A), it is difficult to uniformly charge the obtained toner if it is 2 μm or less, so image defects are likely to occur. Since it becomes difficult to obtain satisfactory image quality due to the increase in size, the number average particle diameter of the colored resin particles (A) is suitably in the range of 2 μm to 10 μm. In particular, the number average particle diameter is preferably 2 μm to 5 μm in order to achieve the purpose of improving the image quality.

  The method for producing the aqueous dispersion of the colored resin particles (A) is not particularly limited, but in consideration of the particle size controllability and production efficiency for the small particle size toner and the degree of freedom in selecting the resin material, the colorant An aqueous dispersion in which colored resin particles obtained by agglomerating an aqueous dispersion made of a self-dispersing resin are dispersed is suitable.

  As a method for obtaining an aqueous dispersion of colored resin particles obtained from the aqueous dispersion containing the self-dispersing resin, for example, an aqueous dispersion of fine resin particles of 1 μm or less made of a self-dispersing resin, an aqueous dispersion of a colorant, After mixing the aqueous charge control agent dispersion and the aqueous release agent dispersion, an aggregating agent is added to aggregate the dispersed particles.

  The self-dispersing resin may be any resin that can be dispersed using a stirrer in an aqueous medium heated without using a dispersant such as a surfactant, such as sulfonic acid, sulfonate, carboxylic acid, and carboxylic acid. A resin having a hydrophilic group such as a salt in the side chain can be used.

  The dispersed particle size of the self-dispersing resin depends on the hydrophilic group content in the self-dispersing resin, and the larger the content, the smaller the dispersed particle size. Further, the dispersed particle size of the self-dispersing resin also depends on the molecular weight of the resin, and the dispersed particle size having a small molecular weight becomes small. Therefore, the dispersed particle size of the self-dispersing resin in the aqueous medium can be controlled by changing the hydrophilic group content and the molecular weight of the resin.

  Among the self-dispersing resins, if a resin using a self-dispersing resin having a carboxylate in the side chain is aggregated using a flocculant having a polyvalent metal ion such as magnesium sulfate, carboxylate ions and magnesium Since an ion cross-linked structure can be formed through ions, the same effect as that of the high molecular weight resin can be obtained, and the hot offset resistance can be improved. In the melt emulsification method, if it is attempted to disperse using a resin having a large molecular weight from the beginning, there is a demerit that the time required for the dispersion becomes long and the productivity is lowered. Since a small resin can be used, both the productivity in the dispersion process and the improvement of the hot offset resistance of the obtained toner can be achieved. As the flocculant having a polyvalent metal ion, for example, magnesium sulfate, magnesium sulfate, aluminum sulfate, or the like can be used.

  An aqueous dispersion of colored resin particles made of a self-dispersing resin having a carboxylate is, for example, an aqueous dispersion of a self-dispersing resin having a carboxylate dispersed in a number average particle size of 0.01 μm or more and 0.3 μm or less. The dispersion is mixed with an aqueous colorant dispersion, a release agent aqueous dispersion, and a charge control agent aqueous dispersion dispersed to a number average particle size of 0.3 μm or less, and a flocculant is added. At this time, it is desirable that the cationic surfactant is not substantially contained so that non-uniform aggregation does not occur when each aqueous dispersion is mixed.

  Examples of the method for producing an aqueous dispersion of the self-dispersing resin include a self-dispersing resin having a carboxylate in a side chain in an aqueous medium containing ammonia or sodium hydroxide, and softening the resin under pressure. There is a method of manufacturing by stirring at a temperature above the point.

  At this time, since it is necessary to disperse the self-dispersing resin at a high temperature under basic conditions, the styrene resin is more preferable than the polyester resin whose molecular weight is easily changed by hydrolysis.

  The average particle diameter of the aqueous fine dispersion dispersed in the aqueous dispersion is preferably 0.01 μm to 0.3 μm. If it is 0.3 μm or more, it is difficult to uniformly disperse the colorant in the colored resin particles (A), and the color reproducibility of the toner is lowered. Further, if the resin is 0.01 μm or less, the hydrophilicity is too high, so that sufficient moisture resistance cannot be obtained for the obtained toner.

  The self-dispersing styrene resin having a carboxylate in the side chain can be obtained by copolymerizing a vinyl monomer having a carboxylic acid and another vinyl monomer.

  As the vinyl monomer having carboxylic acid, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid and the like can be used.

  Other vinyl monomers used for copolymerization with the above monomers include styrene, vinyl toluene, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, ethyl hexyl acrylate, methyl methacrylate, Ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, ethyl hexyl methacrylate and the like can be used.

  The ionic group contained in the resin has a function of imparting water dispersibility to the styrene resin, but when the counter cation is a polyvalent ion, the water dispersibility cannot be sufficiently exhibited. Therefore, it is preferable that the counter cation of these ionic group-containing monomers when polymerizing the styrene series is a monovalent cation.

<Colorant>
As the colorant aqueous dispersion used when the colored resin particles (A) are produced from the aqueous dispersion of resin particles, the colorant is stirred with a surfactant with a stirrer, and the number average particle size is 0.3 μm or less. Those emulsified and dispersed in can be used. As the colorant, known ones can be used, and there is no particular limitation except for a water-soluble dye that does not aggregate even when a flocculant is added.

  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) are preferable.

  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), 122 (quinacridone magenta) and 209 (dichloroquinacridone red) are preferred.

  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) are preferable.

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

  The colorant of the present invention can be dispersed using a surfactant or the like, and in particular, an aqueous solution of a resin particle having a colorant aqueous dispersion and a sulfonate salt using an aggregating agent having a polyvalent metal ion. When the colored resin particles (A) are produced from the dispersion, it is desirable from the viewpoint of uniform particle size control that the cationic surfactant is not substantially contained as the colorant dispersant.

  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. When the amount is less than 0.1% by weight, it is difficult to obtain a sufficient image density. When the amount exceeds 20% by weight, it is difficult to ensure dispersibility of the colorant in the formed image.

  Further, a self-dispersible pigment that can be dispersed without adding a surfactant as a colorant can also be used. Examples of self-dispersing pigments include sulfonic acid groups, carboxyl groups and polymers on the pigment surface as disclosed in JP-T-10-510661, JP-T 2000-513396, and JP-T 2003-519709. Are preferably introduced directly onto the pigment surface. Moreover, what coated the pigment surface with a sulfonic acid group, a carboxyl group, a polymer, etc. by the phase inversion emulsification method etc. can also be used. The self-dispersing pigment has a hydrophilic functional group on the surface of the pigment, and the hydrophilic functional group is preferably an ionic group and / or an ionizable group. Examples of the hydrophilic functional group include a carboxylic acid group, a group having a carboxylate, a sulfonic acid group, a group having a sulfonate, a sulfophenyl group, a group having a benzenesulfonate, a p-sulfophenyl group, p -Mentioning a group having a benzenesulfonate, a group having a carboxyphenyl group, a group having a benzenecarboxylate, a sulfoamide group, a group having an amidosulfate, a group having a quaternary ammonium salt, a derivative thereof and a mixture thereof Can do.

  Self-dispersing pigments can be easily dispersed uniformly in water, and pigment agglomerates are unlikely to occur in the resulting toner, and an image with excellent color reproducibility can be obtained.

<Release agent>
A release agent can also be used in the toner of the present invention. That is, although the colored resin particles (A) according to the present invention contain at least a colorant, it is a matter of course that a release agent may be contained in the colored resin particles (A) like this colorant. . As a method of adding the release agent to the inside of the toner, for example, there is a method of aggregating an aqueous release agent dispersion together with an aqueous resin dispersion.

  As the release agent aqueous dispersion, a dispersion obtained by stirring and dispersing a release agent together with a dispersant and a surfactant with a stirring device can be used. An aqueous dispersion in which a release agent is dispersed so that the number average particle diameter is 1 μm or less can be used, but in order to obtain a toner with more excellent transparency and color reproducibility, it is dispersed to 0.3 μm or less. Is preferably used.

  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. By adding the above releasing agent to the toner of the present invention, it is possible to give a releasing effect to the fixing roller at the time of fixing.

<Charge control agent>
In the toner of the present invention, a charge control agent can also be used. That is, although the colored resin particles (A) according to the present invention contain at least a colorant, it is a matter of course that a charge control agent may be contained in the colored resin particles (A) as well as this colorant. . Moreover, you may contain the mold release agent demonstrated previously simultaneously. Therefore, as a method for adding the charge control agent to the inside of the toner, for example, a method in which the charge control agent is dispersed in the resin in advance using a melt kneader, or an aqueous release agent dispersion is agglomerated together with the aqueous resin dispersion There is a way to make it.

  As the charge control agent aqueous dispersion, a dispersion obtained by stirring the charge control agent together with the dispersant and the surfactant with a stirring device can be used. An aqueous dispersion in which the charge control agent is dispersed so that the number average particle diameter is 1 μm or less can be used, but in order to obtain a toner with more excellent transparency and color reproducibility, it is dispersed to 0.3 μm or less. Is preferably used.

  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. By adding the charge control agent to the toner of the present invention, the charging characteristics of the toner can be controlled.

  In the production process of the colored resin particles (A), when adjusting each of the aqueous colorant dispersion, the aqueous release agent dispersion, the aqueous charge control agent dispersion, and the aqueous resin dispersion, the dispersion particle size is controlled. In this case, a surfactant can be used as long as the moisture resistance is not affected.

  As the surfactant that can be used, any of nonionic surfactants, anionic surfactants, cationic surfactants and amphoteric surfactants may be used. When aggregating agents having polyvalent metal ions such as magnesium sulfate and aluminum sulfate are used for agglomerating resin particles, the interface used for the colorant and mold release agent is used in that a uniform aggregate is formed. It is preferable that the surfactant is substantially free of a cationic surfactant.

  Examples of the nonionic surfactant include polyoxyalkylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether; polyoxyalkylene alkyl phenol ethers such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether. Sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monostearate, sorbitan trioleate; polyoxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate; polyoxyethylene monolaurate, polyoxyethylene monostea Polyoxyalkylene fatty acid esters such as oleates; oleic acid monoglycerides, stearic acid monoglycerides, etc. Glycerin fatty acid esters; can be exemplified polyoxyethylene polypropylene block copolymer and the like.

  Examples of the anionic surfactant include fatty acid salts such as sodium stearate, sodium oleate and sodium laurate; alkylaryl sulfonates such as sodium dodecylbenzene sulfonate; alkyl sulfate esters such as sodium lauryl sulfate; Alkyl sulfosuccinic acid ester salts such as sodium octyl sulfosuccinate, sodium dioctyl sulfosuccinate, sodium polyoxyethylene lauryl sulfosuccinate and derivatives thereof; polyoxyalkylene alkyl ether sulfates such as polyoxyethylene lauryl ether sulfate; polyoxyethylene And polyoxyalkylene alkylaryl ether sulfate esters such as nonylphenol ether sulfate

  Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate; quaternary ammonium salts such as lauryltrimethylammonium chloride and alkylbenzyldimethylammonium chloride; polyoxyethylalkylamine and the like. Examples of the surfactant include alkyl betaines such as lauryl betaine.

  Moreover, what substituted a part of hydrogen of the alkyl group by the fluorine in the said surfactant can also be used.

<Aqueous dispersion of resin particles (B)>
As an aqueous dispersion of resin particles (B) containing a styrene resin having a carboxylate in the side chain used as a shell material (coat material) of the colored resin particles (A), a method such as a melt emulsification method or an emulsion polymerization method is used. However, as an example, a styrene resin having a carboxylate in the side chain and having an acid value of 0.1 to 10 mgKOH / g is put into an aqueous medium containing ammonia or sodium hydroxide, An aqueous dispersion prepared by stirring at a temperature higher than the softening point of the resin can be used.

  At this time, the carboxylic acid in the side chain is converted into a carboxylate, so that the hydrophilicity is increased so that the resin itself can be dispersed in the aqueous medium without using a surfactant. In terms of imparting hydrophilicity, the cation of the carboxylate is preferably monovalent, and alkali metal hydroxides such as sodium hydroxide and ammonia are suitable.

  Since the carboxylate has high hydrophilicity, it imparts self-dispersibility to the resin itself. However, the carboxylate on the surface of the toner particles can be returned to the carboxylic acid by acid treatment. As a result, the hydrophobicity of the toner surface obtained by acid treatment after the resin particles are coated on the core particles is increased, and the toner has excellent moisture resistance with little fluctuation in the environment of charge amount and insulation resistance.

  The particle size of the self-dispersing resin dispersed in the aqueous medium can be controlled by changing the molecular weight of the resin and the carboxylate content in the resin. If the molecular weight of the resin is reduced, emulsification is facilitated and the dispersed particle size is reduced. If the amount of carboxylate in the resin is increased, emulsification is facilitated and the dispersed particle size is reduced, but if the acid value is too high, the hygroscopicity is increased, and as a result, the resulting toner has moisture resistance, i.e., The acid value is preferably 0.1 to 10 mgKOH / g in order to cause a decrease in charge amount and a decrease in transfer efficiency in a high humidity environment. That is, the acid value is a major factor for controlling the particle size together with the molecular weight of the resin, but if the acid value is too large (10 mg KOH / g or more), the moisture resistance which is the object of the present invention can be improved. Can not. Therefore, from the viewpoint of moisture resistance, the lower the acid value, the better. However, if it is too low (0.1 mg KOH / g or less), it is difficult to reduce the particle size. Since the particle size cannot be controlled only by the acid value, it is difficult to define the lower limit value. However, the acid value at which the toner cannot be produced regardless of how other factors are set is defined as the lower limit value.

  As the self-dispersing resin having a carboxylate in the side chain, it is possible to use a polyester resin in addition to the styrene resin, but the toner can have high hydrophobicity in the acid treatment step after encapsulation. In this respect, a styrene resin having an acid value of 0.1 to 10 mgKOH / g is preferable. As a result, the obtained toner is excellent in moisture resistance, and has excellent environmental characteristics in which the triboelectric charge amount and the insulation resistance are less dependent on the environment.

  Further, the particle size and dispersion rate of the self-dispersing resin to be dispersed are also affected by the temperature of the aqueous medium. Stirring a styrene resin while heating an aqueous medium containing alkali metal hydroxide such as sodium hydroxide or ammonia to a temperature higher than the softening point of the resin has a sharper production efficiency and dispersion particle size distribution of the resin. Is preferable. By coating the core particles with a resin aqueous dispersion having a sharp particle size distribution, a capsule toner having a uniform coating layer can be obtained. When heating an aqueous medium to 100 degreeC or more, it can carry out using the apparatus which can be heated while pressurizing an aqueous medium. As an apparatus that can be used, for example, CLEARMIX (manufactured by M Technique) can be used.

  The self-dispersing styrenic resin having a carboxylate salt in the side chain used in the present invention can be obtained by copolymerizing a vinyl monomer having a carboxylic acid and another vinyl monomer.

  As the vinyl monomer having carboxylic acid, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid and the like can be used.

  Other vinyl monomers used for copolymerization with the above monomers include styrene, vinyl toluene, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, ethyl hexyl acrylate, methyl methacrylate, Ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, ethyl hexyl methacrylate and the like can be used.

  In the process of forming the resin particles (B), in addition to the self-dispersing resin having a carboxylate in the side chain, a resin having no self-dispersing property can be added at the same time. In that case, when the content of the self-dispersing resin having a carboxylate in the side chain in the resin particle (B) is 50% by weight or less, it becomes difficult to make a uniform aqueous dispersion. The resin having a salt is preferably 50% by weight or more.

  If the focus is on improving the moisture resistance of the toner surface (humidity of triboelectric charge and electrical resistance), it is preferable that the acid value of the resin is low as long as the toner productivity is not affected. In the styrene acrylic resin generally used as a resin, the blending ratio of styrene monomer also affects the hydrophobicity. The blending ratio of styrene is preferably 50% or more, more preferably 75% or more.

  The glass transition point of the resin particles (B) can usually be from 45 ° C. to 75 ° C., but the glass transition point of the resin particles (B) is 2 ° C. to 10 ° C. higher than the glass transition point of the colored resin particles (A). The coagulation resistance under the above) and the low-temperature fixability are preferable.

  The thickness of the coating layer of the resin particles (B) is preferably 0.3 μm or more and 1 μm or less because sufficient storage stability cannot be obtained when the thickness is 0.3 μm or less, and low temperature fixability is lowered when the thickness is 1 μm or more.

  When the number average particle size of the resin particles (B) is 0.3 μm or more, the coating layer of the colored resin particles (A) becomes too thick or it is difficult to obtain a uniform coating layer. Therefore, the number of resin particles (B) The average particle size is 0.3 μm or less, more preferably 0.03 μm or less.

  Furthermore, it is preferable that the softening point of the colored resin particles (A) is 10 ° C. to 30 ° C. higher than the softening point of the resin particles (B) from the viewpoint that both low-temperature fixability and hot offset resistance can be achieved. That is, when the amount of heat received from the fixing device at the time of fixing is not sufficient, the low softening point resin existing on the toner surface melts to provide the adhesive force between the toner and the paper surface necessary for fixing the toner. When a large amount of heat is received from the fixing device during fixing, the resin having a high softening point existing in the toner contributes to hot offset resistance.

In addition, the said softening point said by this invention is measured on condition of the following using flow tester CFT-500 type (made by Shimadzu Corporation),
[Measurement conditions for softening point]
Sample amount: 1g
Die size: 1.0 × 1.0
Extrusion load 20kgf / cm ²
Temperature rising rate 6 ℃
Starting temperature: 60 ° C
Preheating time: The temperature at 1/2 stroke measured for 300 seconds was defined as the softening point.

  As a method for agglomerating and coating the resin particles (B) on the surface of the colored resin particles (A), the number average including the colored resin particles (A) having a number average particle diameter of 2 μm to 10 μm and a resin having a carboxylate in the side chain. After mixing an aqueous dispersion composed of resin particles (B) having a particle size of 0.3 μm or less, the aqueous dispersion is heated or a flocculant is added to the resin particles (B) on the surface of the colored resin particles (A). ).

  The thickness of the coating layer can be controlled by the particle diameters of the colored resin particles (A) and resin particles (B) to be mixed and the mixing ratio of the colored resin particles (A) and resin particles (B). The coating layer 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 in two or more layers.

  After the agglomeration coating, it is possible to form a strong coating layer by heating the aqueous medium containing the agglomerates to a temperature equal to or higher than the Tg of the resin in order to form stronger particles. A capsule toner in which the coating layer is hardly peeled off in the tank can be obtained.

<Flocculant>
As a flocculant used when the resin particles (B) are coated on the surface of the colored resin particles (A), or as a flocculant used when the self-dispersing resin particles are agglomerated together with the colorant particles when the colored resin particles (A) are produced. The known substances such as electrolytes and organic substances having ions can be used, but the flocculant having a polyvalent metal ion capable of forming an ionic cross-linking structure between the polymer molecules has the effect of increasing the molecular weight of the resin. It is preferable in a certain point. As the flocculant having a polyvalent metal ion, a polyvalent metal salt such as magnesium sulfate or aluminum sulfate is preferable because it is easily dissolved in water and easily washed with pure water.

  A method for converting the carboxylate in the side chain to a carboxylic acid can be performed by adding an acid during or after aggregation. By this method, the carboxylate on the surface of the toner particles is converted to carboxylic acid and the hydrophobicity (moisture resistance) is increased.

  As a specific treatment method, for example, an aqueous dispersion of aggregated particles is heated to a temperature of Tg or higher to form stronger aggregated particles, and then the pH is adjusted to 2-3 in a suspension in which the aggregated particles are dispersed. A method of adding an adjusted aqueous hydrochloric acid solution is preferred. The acid-treated suspension includes a method of obtaining the toner particles of the present invention by removing the flocculant and the acid component by repeating filtration and washing with pure water and drying the suspension.

<Washing water>
The pure water used for cleaning preferably has a conductivity of 20 μS / cm or less. Such pure water can be obtained by a known method, and examples thereof include an activated carbon method, an ion exchange method, a distillation method, and a reverse osmosis method. Further, a plurality of methods may be combined. Moreover, the temperature of the pure water at the time of washing | cleaning has preferable 10 to 80 degreeC.

<External additive>
As described above, a known external additive can be added to the toner of the present invention 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.

  As described above, a capsule toner that achieves the object of the present invention can be obtained. The particle diameter of the toner of the present invention is not particularly limited, but a number average particle diameter of 3 to 11 μm is preferable in consideration of improvement in image quality. In consideration of toner scattering in the developing device, image density stability, and excellent dot reproducibility, the number average particle diameter is more preferably 4 to 6 μm.

  The toner obtained in the present invention can be used as a one-component developer or a two-component developer. As the two-component developer, for example, a developer in which the toner of the present invention and a carrier are mixed can be used.

  As the carrier, known ones can be used, and examples thereof include a carrier in which ferrite particles and iron powder particles are surface-coated with a coating material, and a carrier in which magnetic powder is dispersed in a binder resin. Examples of the coating material include polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, metal compound of ditertiary butylsalicylic acid, styrene resin, acrylic resin, polyacid, polyvinyl Lar, nigrosine, amino acrylate resin, basic dye, basic dye lake, silica fine powder, alumina fine powder, carbon black and the like. Moreover, a coating substance may be used individually by 1 type, and may be used in combination of 2 or more type. Although there is no restriction | limiting in particular as a volume average particle diameter of a carrier, A 20 micrometers-50 micrometers carrier is preferable when the improvement of image quality and stability of image density are considered.

  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.

<< Manufacturing process of self-dispersing styrene acrylic resin aqueous dispersion (C) >>
In this example, even if the core particle is made of a resin having a high acid value (20 mgKOH / g or more), a toner having excellent moisture resistance can be obtained by using a coating material having a low acid value (10 mgKOH / g or less). In order to demonstrate that it is obtained, styrene acrylic resin obtained by copolymerizing acrylic acid, styrene, butyl acrylate and butyl methacrylate (softening point: 131 ° C., glass transition point: 58 ° C., acid value: 20 mgKOH / g ) 500 parts by weight of a mixed solution obtained by adding 100 parts by weight and 1.5 parts by weight of sodium hydroxide to 398.5 parts by weight of pure water was stirred using a pressure stirrer while heating to 150 ° C. Dispersion processing was performed. Thereafter, the temperature of the aqueous medium was gradually lowered to room temperature to obtain a styrene acrylic resin aqueous dispersion (C). The number average particle diameter of the finely dispersed particles present in the obtained aqueous dispersion (C) was 0.2 μm.

<< Production Process of Colorant Aqueous Dispersion (D) >>
A mixed solution 278 in which 50 parts by weight of a cyan pigment (manufactured by BASF: Eupolene Blue 69-1501) and 5 parts by weight of an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen R) are added to 223 parts by weight of ion-exchanged water. A weight part was dispersed with a homogenizer (manufactured by Polytron, PT3000) for 20 minutes, and further dispersed with an ultrasonic homogenizer to obtain an aqueous colorant dispersion (D) having a particle size of 0.2 μm.

≪Manufacturing process of release agent aqueous dispersion (E) ≫
50 parts by weight of paraffin wax (Nippon Seiwa Co., Ltd., HNP10, melting point: 72 ° C.) and 5 parts by weight of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen R) are added to 161 parts by weight of ion-exchanged water. Dispersion treatment was performed with a homogenizer (manufactured by Polytron, PT3000) while heating 216 parts by weight of the liquid to 95 ° C. to obtain an aqueous release agent dispersion (E) having a number average particle size of 0.3 μm.

≪Aqueous dispersion mixing process≫
The self-dispersing styrene resin aqueous dispersion (C), the colorant aqueous dispersion (D) and the release agent aqueous dispersion (E) have solid content concentrations of 90% by weight, 5% by weight and 5% by weight, respectively. The mixture (F) was obtained.

≪Core particle manufacturing process≫
While stirring the obtained mixed liquid with a homogenizer (manufactured by Polytron, PT3000: rotation speed 2000 rpm), a 0.1 wt% magnesium sulfate aqueous solution was dropped. Thereafter, this mixed liquid was stirred for 1 hour to obtain an aqueous dispersion (G) in which colored resin particles (A) having a volume average particle diameter of 5.1 μm were dispersed.

<< Production Process of Resin Particle (B) Aqueous Dispersion (H) >>
Styrene acrylic resin obtained by copolymerizing acrylic acid, styrene, butyl acrylate, butyl methacrylate (softening point: 123 ° C., glass transition point 63 ° C., acid value 7 mg KOH / g, styrene content: 80% by weight) 100 Dispersion of resin by stirring with a pressure stirrer while heating 500 parts by weight of a mixed solution in which 39 parts by weight of sodium hydroxide and 0.5 parts by weight of sodium hydroxide were added to 399.5 parts by weight of pure water Processed. Thereafter, the temperature of the aqueous medium was gradually lowered to room temperature to obtain an aqueous styrene acrylic resin dispersion (H). The number average particle diameter of the finely dispersed particles present in the obtained aqueous dispersion (H) was 0.1 μm.

≪Shell material [resin particles (B)] coating process≫
The aqueous dispersion (G) obtained by dispersing the colored resin particles (A) and the aqueous dispersion (H) of the resin particles (B) were mixed so that the solid content concentrations were 80% by weight and 20% by weight, respectively. The mixed liquid was heated to 75 ° C. and stirred for 30 minutes, and then the aqueous medium was further heated to 90 ° C. and stirring was continued for 30 minutes to form a well-shaped aggregate.

≪Filter washing process≫
The supernatant liquid of the aqueous medium containing aggregates was exchanged with pure water three times, and then an aqueous hydrochloric acid solution having a pH of 2 was added. Thereafter, the agglomerates were washed twice with pure water and filtered to take out wet cake-like aggregates of toner particles. In addition, the pure water used for washing | cleaning utilized the 0.5 micro S / cm water prepared from the tap water using the ultrapure water manufacturing apparatus (ADVANTEC company_made: Ultra Pure Water System CPW-102).

≪Drying process≫
The wet cake-like aggregate of toner particles taken out using a vacuum dryer was dried to produce toner particles having a volume average particle size of 5.5 μm. The particle size of the toner particles was measured using Coulter Multisizer II (manufactured by Coulter). In addition, when the dispersion state of the colorant and release agent of the obtained toner was observed using a transmission electron microscope, non-uniform aggregation and aggregates of 0.3 μm or more were not observed, and the dispersion state was uniform. I was able to confirm.

≪External addition process≫
To 100 parts by weight of the toner obtained above, 0.7 parts by weight of hydrophobic silica fine particles having an average primary particle size of 12 nm and 1.2 parts by weight of hydrophobized titanium oxide fine particles having an average primary particle size of 30 nm are mixed with a Henschel mixer. A toner was prepared by

<Production of developer>
The toner was mixed with a silicon-coated ferrite carrier having an average particle size of 40 μm by a ball mill to prepare a two-component developer having a toner concentration of 8% and a charge amount of 28.5 μc / g.

[Evaluation results]
Using the above toner and developer, evaluation was performed with an actual machine. The evaluation conditions and evaluation results are shown below. As a machine for evaluation, a digital full-color multifunction machine (manufactured by Sharp Corporation: AR-C150) was used, and the toner adhesion amount on the solid image portion on the fixing paper was 0 under normal temperature and normal humidity (20 ° C., humidity 60%). The image was evaluated under the development conditions of 5 mg / cm ² .

(Image quality evaluation)
For the image density, the optical density of the evaluation image was measured using a spectrocolorimetric densitometer (manufactured by Japan Planographic Printing Equipment Co., Ltd .: X-Rite 938). The fog was evaluated as follows. Using a whiteness meter (manufactured by Nippon Denshoku Industries Co., Ltd .: Z-Σ90 COLOR MEASURING SYSTEM), the whiteness of A4 size full-color dedicated paper (manufactured by Sharp Corporation: PP106A4C) is measured, and this value is the first measured value. Let 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, and evaluated according to the following criteria based on the fog density.
W = {100 × (W1-W2) / W1}

  As a result, the toner of the present invention had a high image density (ID = 1.43), no fogging (W = 0.9), and a clear image with high fine dot reproducibility was obtained.

(Moisture resistance evaluation)
As a result of measuring the charge amount at high temperature and high humidity (35 ° C., humidity 80%) and low temperature and low humidity (10 ° C., humidity 25%), 25.9 μc / g in a high temperature and high humidity environment and 31. The toner was 2 μc / g, and the toner was less dependent on the environment. This toner charge amount change amount (17%) is within the allowable range of the process control provided in the evaluator (AR-C150), and the image has a high image density and is free from fog and has a high reproducibility of fine dots. was gotten.

(Transferability evaluation)
As a result of examining the transfer efficiency under each environmental condition, it was found that the transfer efficiency exceeded 90% under any environmental condition and showed satisfactory transfer performance.

(Preservation evaluation)
As a result of putting 300 g of toner in a toner bottle dedicated to AR-C150 and leaving it in a thermostatic bath at 50 ° C. for 2 days, the presence of aggregates was checked with a 400-mesh sieve. Excellent fluidity.

(Fixability evaluation)
As a result of evaluating the toner fixability using an evaluation machine (AR-C150) in which the oil application mechanism of the fixing unit was removed, an image having high gloss without hot offset or cold offset was obtained.

FIG. 7 is a process chart showing an example of a manufacturing method for manufacturing a capsule toner according to the present invention and showing a series of flows according to the toner manufacturing method.

Explanation of symbols

S4 Shell material coating process S5 Filtration washing process S6 Drying process

Claims (12)

  The colored resin particles (A) containing at least a colorant are agglomerated with resin particles (B) made of a styrene resin having a carboxylate in the side chain, and the carboxylates of the resin particles (B) are converted into carboxylic acids. Converted capsule toner.   The resin particles (B) are resin particles (B) obtained by dispersing a styrene resin having an acid value of 0.1 to 10 mg KOH in an aqueous medium containing ammonia or an alkali metal hydroxide. The capsule toner according to claim 1.   The resin particles (B) are resin particles (B) obtained by dispersing a styrene resin at a temperature higher than the softening point of the resin in an aqueous medium containing ammonia or an alkali metal hydroxide. The capsule toner according to claim 1.   An aqueous dispersion (C) in which colored resin particles (A) are dispersed in a resin having a carboxylate in the side chain, and an aqueous dispersion in which a colorant having a number average particle size of 0.3 μm or less is dispersed. The capsule toner according to claim 1, wherein the toner is an aggregate obtained by adding an aggregating agent having a polyvalent metal ion to a mixture with (D).   2. The capsule toner according to claim 1, wherein the glass transition point of the resin particles (B) having a carboxylate in the side chain is 2 ° C. to 10 ° C. higher than the glass transition point of the resin of the colored resin particles (A). .   2. The capsule toner according to claim 1, wherein the softening point of the resin of the colored resin particles (A) is higher by 10 ° C. to 30 ° C. than the softening point of the resin particles (B) having a carboxylate in the side chain.   The capsule toner according to claim 4, wherein the colorant contained in the aqueous colorant dispersion (D) is a self-dispersing pigment substantially free of an emulsifier.   5. The capsule toner according to claim 4, wherein the colored resin particles (A) are aggregates obtained by further mixing a release agent dispersion having a particle size of 0.3 μm or less.   5. The capsule toner according to claim 4, wherein the colored resin particles (A) are aggregates obtained by further mixing a charge control agent dispersion having a particle size of 0.3 μm or less.   The capsule toner according to claim 1, wherein one or more types of external additives having a particle diameter of 0.03 μm or more are attached to the surface of the toner particles.   A developer comprising the toner according to claim 1 and a carrier having a volume average particle diameter of 20 μm to 50 μm.   An aqueous dispersion of colored resin particles (A) containing at least a colorant and an aqueous dispersion consisting of styrene resin particles (B) having a carboxylate in the side chain are mixed, and an aggregating agent is added to the resulting mixture. In addition, a method for producing a capsule toner comprising adding an acid after the resin particles (B) are agglomerated and coated on the surface of the colored resin particles (A).

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