JP2011048307A - Capsule toner and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capsule toner having improved blocking resistance without decreasing hot offset resistance, and to provide a method for producing the toner. <P>SOLUTION: The toner includes: a toner base particle containing a binder resin, a release agent and a colorant; and a coating resin layer containing a polyester resin and a styrene-acryl copolymer resin and coating the surface of the toner base particle. The blocking resistance of the toner can be improved by the resin coating layer coating the toner base particle. As the resin coating layer contains a polyester resin and a styrene-acryl copolymer resin, an interface between the polyester resin and the styrene-acryl copolymer resin is present in the resin coating layer, and the release agent included in the toner base particle easily oozes out through the interface during fixing, which prevents decrease in the hot offset resistance. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a capsule toner and a method for producing the same.

  In an electrophotographic image forming apparatus, the surface of the image carrier is uniformly charged by a charging means (charging process), the surface of the image carrier is exposed by an exposure means, and the charge on the exposed portion is dissipated to carry the image. An electrostatic latent image is formed on the body surface (exposure process). Next, a toner which is a colored fine powder having a charge is attached to the electrostatic latent image to form a visible image (development process), and the obtained visible image is transferred to a recording medium such as paper (transfer process). Further, the visible image is fixed on the recording medium by the fixing means by heating, pressing, or other fixing methods (fixing step). An image is formed on the recording medium through the above steps. Further, in order to remove toner remaining on the surface of the image carrier without being transferred to the recording medium, the image carrier is cleaned (cleaning step).

  The toner used for such image formation needs to have functions required not only in the development process but also in the transfer process, the fixing process, and the cleaning process.

  Examples of the toner fixing method include a heat fixing method in which toner is heated and melted and fixed on a recording medium, and a pressure fixing method in which toner is plastically deformed by pressure and fixed on a recording medium.

  In the heat fixing method, in consideration of the simplicity of the fixing device and the image quality after fixing, a heat roll fixing method using a heat roll as a heating medium for heating and melting the toner is often used. In this method, from the viewpoint of energy saving, the toner is required to have a so-called low-temperature fixability in which the toner is melted and fixed at a temperature as low as possible so that the toner can be fixed with a heat roll as low as possible. In order to achieve low-temperature fixability, the softening temperature of the toner particles is lowered by reducing the molecular weight of the binder resin constituting the toner particles or adding a release agent to the toner particles. Yes.

  However, although such toner has low-temperature fixability, for example, if it is left in a car under heat and placed in a high-temperature environment during transportation, the toner softens and aggregates due to heat, resulting in reduced blocking resistance. There is a problem.

  In order to solve such problems, Patent Document 1 discloses a toner having a core / shell structure, which includes a crystalline polyester resin in a core and an amorphous polymer resin as a main component in a shell layer. Yes.

JP 2005-266565 A

  However, in the toner disclosed in Patent Document 1, the core (toner base particles) containing a crystalline polyester resin is covered with a shell layer (resin coating layer) made of an amorphous polymer resin, so that it is resistant to blocking. Even if the property is secured, there is a problem that the seepage of the release agent added to the core at the time of fixing is hindered and the hot offset resistance is lowered, and the blocking resistance and the hot offset resistance are reduced. It is difficult to improve at the same time.

  An object of the present invention is to provide a capsule toner having improved blocking resistance without impairing hot offset resistance and a method for producing the same.

The present invention includes toner base particles containing a binder resin, a release agent and a colorant;
A capsule toner comprising a polyester resin and a styrene-acrylic copolymer resin and having a resin coating layer covering the surface of the toner base particles.

The present invention also provides mixed resin fine particles comprising polyester resin fine particles and styrene-acrylic copolymer resin fine particles on the surface of toner mother particles containing a binder resin, a release agent, and a colorant, thereby forming a resin fine particle adhering mother. Mixed resin fine particle adhesion step for forming particles;
A spraying step of spraying a liquid that plasticizes the mixed resin fine particles and the toner mother particles, wherein the resin fine particle-attached mother particles are in a fluid state;
And a film forming step of forming a resin coating layer on the surface of the toner base particles by forming the mixed resin fine particles into a film by impact force.

In the present invention, the mixed resin fine particle adhesion step comprises:
Mixing the polyester resin fine particles and the styrene-acrylic copolymer resin fine particles to prepare mixed resin fine particles;
A step of mixing the toner base particles and the mixed resin fine particles to form resin fine particle-adhered mother particles having the mixed resin fine particles attached to the surface of the toner mother particles.

In the present invention, the volume average particle diameter Dp of the polyester resin fine particles and the volume average particle diameter Ds of the styrene-acrylic copolymer resin fine particles satisfy the following formula (1).
Ds × 0.8 ≦ Dp ≦ Ds × 1.2 (1)

  In the invention, it is preferable that the mixed resin fine particles contain 30% by weight or more and 70% by weight or less of the polyester resin fine particles.

  According to the present invention, the blocking resistance can be improved by the resin coating layer covering the toner base particles. In addition, since the resin coating layer contains a polyester resin and a styrene-acrylic copolymer resin, the resin coating layer has an interface between the polyester resin and the styrene-acrylic copolymer resin. Since the contained release agent easily oozes through this interface, the hot offset resistance is not impaired.

  Further, according to the present invention, since the liquid for plasticizing these particles is sprayed onto the toner base particles and the mixed resin fine particles comprising the polyester resin fine particles and the styrene-acrylic copolymer resin fine particles, these particles are plasticized. The resin coating layer can be formed with a small impact force on the surface of the toner base particles. Further, since the heat of vaporization is lost when the sprayed liquid evaporates, even if the toner base particles are heated by impact force, the toner base particles are not heated above the boiling point of the sprayed liquid. Therefore, it is possible to suppress the release agent from melting from the inside of the toner base particles during the film forming step.

  According to the invention, in the mixed resin fine particle attaching step, the polyester resin fine particles and the styrene-acrylic copolymer resin fine particles are mixed in advance to prepare mixed resin fine particles, and then the toner base particles and the mixed resin are prepared. Fine particles are mixed to form resin fine particle-adhered mother particles in which mixed resin fine particles adhere to the surface of the toner mother particles.

  By preparing the mixed resin fine particles in advance, the uniformly mixed resin fine particles adhere to form a uniform resin coating layer.

  Further, according to the present invention, the volume average particle diameter Dp of the polyester resin fine particles and the volume average particle diameter Ds of the styrene-acrylic copolymer resin fine particles satisfy Ds × 0.8 ≦ Dp ≦ Ds × 1.2. Thus, mixed resin fine particles are prepared.

  By suppressing the difference in volume average particle size between the polyester resin fine particles and the styrene-acrylic copolymer resin fine particles, in the formed resin coating layer, the interface between the polyester resin and the styrene-acrylic copolymer resin is on the toner base particle surface. It is formed so as to be substantially orthogonal to the direction. As a result, the release agent can easily ooze out from the toner base particles through the resin coating layer, and the hot offset resistance can be improved more effectively.

  According to the invention, the mixed resin fine particles contain the polyester resin fine particles in an amount of 30 wt% or more and 70 wt% or less, whereby hot offset resistance and blocking resistance can be further improved.

It is process drawing showing an example of the procedure of the manufacturing method of the capsule toner of this invention. FIG. 3 is a front view showing a configuration of a toner manufacturing apparatus 201 used in the capsule toner manufacturing method of the present invention. FIG. 3 is a schematic cross-sectional view of the toner manufacturing apparatus 201 shown in FIG. 2 as viewed from a cutting plane line A200-A200. FIG. 3 is a side view showing a configuration around a powder input unit 206 and a powder recovery unit 207.

1. Toner Manufacturing Method FIG. 1 is a process diagram showing an example of the procedure of a capsule toner manufacturing method of the present invention. The capsule toner manufacturing method of the present invention includes a toner base particle preparation step S1 for preparing toner base particles, a resin fine particle preparation step S2 for preparing resin fine particles, and a coating step S3 for coating the toner base particles with resin fine particles. Including.

(1) Toner mother particle production step S1
In the toner base particle preparation step S1, toner base particles to be coated with the resin coating layer are prepared. The toner base particles are particles containing a binder resin, a release agent, and a colorant, and the production method thereof is not particularly limited, and can be performed by a known method. Examples of the method for producing the toner base particles include dry methods such as a pulverization method and wet methods such as a suspension polymerization method, an emulsion aggregation method, a dispersion polymerization method, a dissolution suspension method, and a melt emulsification method. Hereinafter, a method for producing toner base particles by a pulverization method will be described.

(Method for preparing toner mother particles by pulverization method)
In the production of toner base particles by a pulverization method, a toner composition containing a binder resin, a colorant and other additives is dry-mixed with a mixer and then melt-kneaded with a kneader. The kneaded material obtained by melt kneading is cooled and solidified, and the solidified material is pulverized by a pulverizer. Thereafter, particle size adjustment such as classification is performed as necessary to obtain toner mother particles.

  Known mixers can be used, such as Henschel mixer (trade name, manufactured by Mitsui Mining Co., Ltd.), super mixer (trade name, manufactured by Kawata Co., Ltd.), Mechano Mill (trade name, manufactured by Okada Seiko Co., Ltd.), etc. Henschel type mixing device, Ong mill (trade name, manufactured by Hosokawa Micron Corporation), hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.), Cosmo system (trade name, manufactured by Kawasaki Heavy Industries, Ltd.), and the like.

  A well-known thing can be used also as a kneading machine, for example, common kneading machines, such as a twin-screw extruder, a 3 roll, a laboratory blast mill, can be used. More specifically, for example, TEM-100B (trade name, manufactured by Toshiba Machine Co., Ltd.), PCM-65 / 87, PCM-30 (all of which are trade names, manufactured by Ikegai Co., Ltd.), etc. Extruder, Needex (trade name, manufactured by Mitsui Mining Co., Ltd.) and other open roll type kneaders. Among these, an open roll type kneader is preferable.

  As the pulverizer, for example, a jet type pulverizer that pulverizes using a supersonic jet stream, and a solidified material in a space formed between a rotor (rotor) and a stator (liner) that rotate at high speed. An impact pulverizer that introduces and pulverizes can be used.

  For classification, a known classifier capable of removing excessively pulverized toner base particles by classification with centrifugal force and wind force can be used. For example, a swirl type wind classifier (rotary wind classifier) can be used.

  As described above, the toner base particles include a binder resin, a release agent, and a colorant. The binder resin is not particularly limited, and a known binder resin for black toner or color toner can be used. For example, styrene resins such as polystyrene and styrene-acrylic acid ester copolymer resin can be used. And acrylic resins such as polymethyl methacrylate, polyolefin resins such as polyethylene, polyesters, polyurethanes, and epoxy resins. Moreover, you may use resin obtained by mixing a raw material monomer mixture with a mold release agent and performing a polymerization reaction. Binder resin can be used alone or in combination of two or more.

  Among the above-mentioned binder resins, polyester is excellent in transparency and can give toner particles good powder fluidity, low-temperature fixability, secondary color reproducibility, etc., and is therefore suitable as a binder resin for color toners. It is. Known polyesters can be used, and examples thereof include polycondensates of polybasic acids and polyhydric alcohols.

  As the polybasic acid, those known as polyester monomers can be used, for example, terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid and other aromatic carboxylic acids, maleic anhydride, Examples thereof include aliphatic carboxylic acids such as fumaric acid, succinic acid, alkenyl succinic anhydride, and adipic acid, and methyl esterified products of these polybasic acids. A polybasic acid can be used individually by 1 type, or can use 2 or more types together.

  As the polyhydric alcohol, those known as monomers for polyesters can be used. For example, aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, hexanediol, neopentylglycol, glycerin, cyclohexanediol, cyclohexanediene, etc. Examples thereof include aromatic diols such as alicyclic polyhydric alcohols such as methanol and hydrogenated bisphenol A, ethylene oxide adducts of bisphenol A, and propylene oxide adducts of bisphenol A. A polyhydric alcohol can be used alone or in combination of two or more.

  The polycondensation reaction between the polybasic acid and the polyhydric alcohol can be carried out according to a conventional method. For example, the polybasic acid and the polyhydric alcohol are contacted in the presence or absence of an organic solvent and in the presence of a polycondensation catalyst. The process is terminated when the acid value, softening temperature, etc. of the produced polyester reach a predetermined value. Thereby, polyester is obtained.

  When a methyl esterified product of a polybasic acid is used as a part of the polybasic acid, a demethanol polycondensation reaction is performed. In this polycondensation reaction, for example, the carboxyl group content at the end of the polyester can be adjusted by appropriately changing the mixing ratio of polybasic acid and polyhydric alcohol, the reaction rate, etc., and thus the properties of the resulting polyester are modified. it can. When trimellitic anhydride is used as the polybasic acid, a modified polyester can also be obtained by easily introducing a carboxyl group into the main chain of the polyester. A self-dispersible polyester in water in which a hydrophilic group such as a carboxyl group or a sulfonic acid group is bonded to the main chain and / or side chain of the polyester can also be used. Further, polyester and acrylic resin may be grafted.

  The binder resin preferably has a glass transition temperature of 30 ° C. or higher and 80 ° C. or lower. When the glass transition temperature of the binder resin is less than 30 ° C., blocking in which the toner thermally aggregates easily occurs in the image forming apparatus, and storage stability may be deteriorated. When the glass transition temperature of the binder resin exceeds 80 ° C., the fixability of the toner to the recording medium is lowered, and there is a possibility that fixing failure occurs.

  As the colorant, organic dyes, organic pigments, inorganic dyes, inorganic pigments and the like commonly used in the electrophotographic field can be used.

  Examples of the black colorant include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, nonmagnetic ferrite, magnetic ferrite, and magnetite.

  Examples of yellow colorants include chrome lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa yellow G, Hansa yellow 10G, benzidine yellow G, and benzidine. Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 180, C.I. I. And CI Pigment Yellow 185.

  Examples of the orange colorant include red chrome yellow, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indanthrene brilliant orange RK, benzidine orange G, indanthrene brilliant orange GK, C.I. I. Pigment orange 31, C.I. I. And CI Pigment Orange 43.

  Examples of red colorants include bengara, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, risol red, pyrazolone red, watching red, calcium salt, lake red C, lake red D, and brilliant carmine 6B. Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B, C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of purple colorants include manganese purple, fast violet B, and methyl violet lake.

  Examples of blue colorants include bitumen, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated products, first sky blue, induslen blue BC, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. And CI Pigment Blue 60.

  Examples of the green colorant include chrome green, chromium oxide, pigment green B, micalite green lake, final yellow green G, C.I. I. And CI Pigment Green 7.

  Examples of the white colorant include compounds such as zinc white, titanium oxide, antimony white, and zinc sulfide.

  One colorant can be used alone, or two or more different colorants can be used in combination. Moreover, even if it is the same color, 2 or more types can be used together. The amount of the colorant to be used is not particularly limited, but is preferably 5 parts by weight or more and 20 parts by weight or less, more preferably 5 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the binder resin.

  The colorant may be used as a master batch in order to uniformly disperse it in the binder resin. Two or more colorants may be used in the form of composite particles. The composite particles can be produced, for example, by adding an appropriate amount of water, lower alcohol or the like to two or more colorants, granulating with a general granulator such as a high speed mill, and drying. The masterbatch and composite particles are mixed into the toner composition during dry mixing.

  As the release agent, those commonly used in this field can be used, for example, petroleum wax such as paraffin wax and derivatives thereof, microcrystalline wax and derivatives thereof, Fischer-Tropsch wax and derivatives thereof, polyolefin wax (polyethylene wax, polypropylene Wax etc.) and derivatives thereof, low molecular weight polypropylin wax and derivatives thereof, hydrocarbon polymer waxes such as polyolefin polymer wax (low molecular weight polyethylene wax etc.) and derivatives thereof, carnauba wax and derivatives thereof, rice wax and derivatives thereof , Candelilla wax and its derivatives, plant wax such as wood wax, animal wax such as beeswax and whale wax, fatty acid amide, phenol fatty acid ester, etc. Oil-based synthetic waxes, long-chain carboxylic acids and their derivatives, long-chain alcohols and derivatives thereof, silicon-based polymers, such as higher fatty acids. Derivatives include oxides, block copolymers of vinyl monomers and waxes, graft modified products of vinyl monomers and waxes, and the like. The amount of the wax used is not particularly limited and can be appropriately selected from a wide range, but is preferably 0.2 to 20 parts by weight, more preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the binder resin. Particularly preferred is 1.0 to 8.0 parts by weight.

  The toner base particles may contain a charge control agent in addition to the binder resin, the release agent and the colorant. As the charge control agent, a charge control agent for positive charge control and negative charge control commonly used in this field can be used.

  Examples of charge control agents for controlling positive charge include nigrosine dyes, basic dyes, quaternary ammonium salts, quaternary phosphonium salts, aminopyrines, pyrimidine compounds, polynuclear polyamino compounds, aminosilanes, nigrosine dyes and derivatives thereof, and triphenylmethane. Derivatives, guanidine salts, amidine salts and the like can be mentioned.

  Charge control agents for controlling negative charges include oil-soluble dyes such as oil black and spiron black, metal-containing azo compounds, azo complex dyes, metal salts of naphthenic acid, metal salts of salicylic acid and its derivatives (metals are metal Chromium, zinc, zirconium, etc.), boron compounds, fatty acid soaps, long-chain alkyl carboxylates, resin acid soaps, and the like. One charge control agent can be used alone, or two or more charge control agents can be used in combination as required. The amount of the charge control agent used is not particularly limited and can be appropriately selected from a wide range, but is preferably 0.5 parts by weight or more and 3 parts by weight or less with respect to 100 parts by weight of the binder resin.

  The toner base particles obtained in the toner base particle preparation step S1 preferably have a volume average particle size of 4 μm or more and 8 μm or less. When the volume average particle size is 4 μm or more and 8 μm or less, a high-definition image can be stably formed over a long period of time. Further, by reducing the toner base particles within this range, it is possible to obtain a high image density even if the amount of adhesion is small, and to reduce the toner consumption. If the volume average particle size of the toner base particles is less than 4 μm, the toner base particles have a small particle size, which may result in high charge and low fluidity. If the toner is highly charged and fluidized, the toner cannot be stably supplied to the photoconductor, which may cause background fogging and a decrease in image density. When the volume average particle size of the toner base particles exceeds 8 μm, the toner base particles have a large particle size, so that the layer thickness of the formed image becomes large, resulting in an image having a remarkable graininess, and a high-definition image cannot be obtained. Further, as the particle size of the toner base particles increases, the specific surface area decreases and the charge amount of the toner decreases. When the charge amount of the toner is small, the toner is not stably supplied to the photoconductor, and there is a possibility that in-machine contamination due to toner scattering occurs.

(2) Resin fine particle preparation step S2
In the resin fine particle preparation step S2, dry resin fine particles are prepared. Any method may be used for drying. For example, dry resin fine particles can be obtained by a method such as hot air heat receiving drying, conductive heat transfer drying, far infrared drying, microwave drying, or the like. The resin fine particles are used as a raw material for the resin coating layer for coating the toner base particles in the subsequent coating step S3. By covering the toner base particles, for example, blocking due to softening of the binder resin contained in the toner base particles can be prevented. Further, since the shape of the resin fine particles remains on the surface of the toner particles in the resin coating layer, toner particles having excellent cleaning properties as compared with toner particles having a smooth surface can be obtained.

  The resin fine particles can be obtained, for example, by emulsifying and dispersing a resin, which is a resin fine particle raw material, with a homogenizer or the like. It can also be obtained by polymerization of monomer components of the resin.

  In the present invention, since the resin coating layer includes a polyester resin and a styrene-acrylic copolymer resin, as resin fine particles, a polyester resin fine particle composed of a polyester resin and a styrene-acrylic copolymer composed of a styrene-acrylic copolymer resin. Resin fine particles are prepared. In the following description, the characteristics common to the polyester resin fine particles and the styrene-acrylic copolymer resin fine particles are simply described as “resin fine particles”.

  The softening temperature of the resin used as the resin fine particle raw material is preferably higher than the glass transition temperature of the binder resin contained in the toner base particles, and more preferably 60 ° C. or higher. As a result, the toner produced by the method of the present invention can prevent the toners from fusing together during storage, and the blocking resistance is improved.

  The softening temperature of the resin used as the resin fine particle raw material is preferably 80 ° C. or higher and 140 ° C. or lower, although it depends on the image forming apparatus in which the toner is used. By using a resin having such a temperature range, a toner having both storage stability and fixing ability can be obtained.

  The volume average particle diameter of the resin fine particles needs to be sufficiently smaller than the average particle diameter of the toner base particles, and is preferably 0.05 μm or more and 1 μm or less. Further, it is more preferably 0.1 μm or more and 0.5 μm or less. When the volume average particle diameter of the resin fine particles is 0.05 μm or more and 1 μm or less, a protrusion having a suitable size is formed on the surface of the toner base particles. As a result, the toner produced by the method of the present invention is easily caught by the cleaning blade during cleaning, and the cleaning property is improved.

  The amount of the resin fine particles added is preferably 3 parts by weight or more with respect to 100 parts by weight of the toner base particles. When the amount is less than 3 parts by weight, it is difficult to uniformly coat the toner base particles, and depending on the type of the toner base particles, the storage stability may be deteriorated.

  As the polyester resin constituting the polyester resin fine particles, the polyester resin used in the above-described binder resin can be used.

  Examples of the styrene-acrylic copolymer resin constituting the styrene-acrylic copolymer resin fine particles include, for example, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene- Examples thereof include a methyl methacrylate copolymer, a styrene-ethyl methacrylate copolymer, a styrene-butyl methacrylate copolymer, and a styrene-acrylonitrile copolymer.

Further, when the volume average particle diameter of the polyester resin fine particles is Dp and the volume average particle diameter of the styrene-acrylic copolymer resin fine particles is Ds, these volume average particle diameters satisfy the following formula (1). Prepare.
Ds × 0.8 ≦ Dp ≦ Ds × 1.2 (1)

  As can be seen from the equation (1), the difference between the volume average particle diameter of the polyester resin fine particles and the volume average particle diameter of the styrene-acrylic copolymer resin fine particles is suppressed to be as small as ± 20%.

  By reducing the difference in volume average particle diameter between the two types of resin fine particles, the interface between the polyester resin and the styrene-acrylic copolymer resin is substantially orthogonal to the surface of the toner base particles in the formed resin coating layer. Formed. When either one of the volume average particle diameters is large, the resin coating layer is formed so that the smaller resin fine particles are covered with the larger resin fine particles, and the resin of the polyester resin and the styrene-acrylic copolymer resin is formed. The interface between them is substantially parallel to the surface of the toner base particles.

  In the resin coating layer, when the interface between the polyester resin and the styrene-acrylic copolymer resin is formed so as to be substantially orthogonal to the surface of the toner base particles, the release agent passes through this interface from the toner base particles to the resin coating. It becomes easy to ooze through the layer, and the hot offset resistance can be improved more effectively.

(3) Covering step S3
The coating step S3 includes a mixed resin fine particle adhesion step S3a, a temperature adjustment step S3b, a spraying step S3c, a film forming step S3d, and a recovery step S3e.

(3) -1 Mixed resin fine particle adhesion step S3a
In the mixed resin fine particle attaching step S3a, first, the polyester resin fine particles prepared in the resin fine particle preparing step S2 and the styrene-acrylic copolymer resin fine particles are preliminarily mixed with a mixer such as a Henschel mixer to obtain mixed resin fine particles.

  At this time, the mixed resin fine particles are preferably mixed so that the polyester resin fine particles are contained in an amount of 30 wt% to 70 wt%.

  Next, the mixed resin fine particles and the toner mother particles produced in the toner mother particle production step S1 are mixed with a mixer such as a Henschel mixer to obtain resin fine particle-adhered mother particles in which the mixed resin fine particles adhere to the toner mother particle surface. .

  A known mixer can be used. For example, Henschel mixer (trade name, manufactured by Mitsui Mining Co., Ltd.), Super mixer (trade name, manufactured by Kawata Co., Ltd.), Mechano Mill (trade name, manufactured by Okada Seiko Co., Ltd.) Etc.

<Toner production device>
FIG. 2 is a front view showing a configuration of a toner manufacturing apparatus 201 used for manufacturing the capsule toner of the present invention. FIG. 3 is a schematic cross-sectional view of the toner manufacturing apparatus 201 shown in FIG. 2 as viewed from the cutting plane line A200-A200. In the coating step S3, for example, a toner manufacturing apparatus 201 shown in FIG. 2 is used, and a resin coating layer is formed on the surface of the toner base particles by an impact force due to a synergistic effect of circulation and stirring in the apparatus. The toner manufacturing apparatus 201 is a rotary stirring device, and includes a powder flow path 202, a spraying means 203, a rotary stirring means 204, a temperature adjustment jacket (not shown), a powder input unit 206, and a powder recovery unit 207. It is comprised including. The rotary stirring means 204 and the powder flow path 202 constitute a circulation means.

(Powder channel)
The powder channel 202 includes a stirring unit 208 and a powder flow unit 209. The stirring unit 208 is a cylindrical container-like member having an internal space. Openings 210 and 211 are formed in the stirring unit 208 which is a rotary stirring chamber. The opening 210 is formed so as to penetrate the side wall including the surface 208a of the stirring unit 208 in the thickness direction at a substantially central portion of the surface 208a on one side in the axial direction of the stirring unit 208. In addition, the opening 211 is formed so as to penetrate the side wall including the side surface 208b of the stirring unit 208 in the thickness direction on the side surface 208b perpendicular to the one-side surface 208a of the stirring unit 208 in the thickness direction. The powder flow part 209 that is a circulation pipe has one end connected to the opening 210 and the other end connected to the opening 211. As a result, the internal space of the stirring unit 208 and the internal space of the powder flow unit 209 are communicated to form the powder flow path 202. Through the powder flow path 202, resin fine particle-adhered mother particles and gas flow. The powder flow path 202 is provided so that the powder flow direction, which is the direction in which the resin fine particle-attached mother particles flow, is constant.

  The temperature in the powder channel 202 is set to be equal to or lower than the glass transition temperature of the toner base particles, and is preferably 30 ° C. or higher and lower than or equal to the glass transition temperature of the toner base particles. The temperature in the powder flow path 202 is almost uniform in any part due to the flow of the toner base particles. When the temperature in the flow path exceeds the glass transition temperature of the toner base particles, the toner base particles are too soft and the toner base particles may be aggregated. On the other hand, if the temperature is lower than 30 ° C., the drying rate of the dispersion liquid becomes slow and the productivity is lowered. Therefore, in order to prevent the aggregation of the toner base particles, it is necessary to maintain the temperature of the powder flow path 202 and the rotating stirring means 204 described later below the glass transition temperature of the toner base particles. Therefore, a temperature adjusting jacket, which will be described later, having an inner diameter larger than the outer diameter of the powder passage tube is disposed on at least a part of the outside of the powder passage 202 and the rotary stirring means 204.

(Rotating stirring means)
The rotating stirring means 204 includes a rotating shaft member 218, a disk-shaped rotating disk 219, and a plurality of stirring blades 220. The rotation shaft member 218 has an axis that coincides with the axis of the stirring unit 208 and is formed on the surface 208c on the other side in the axial direction of the stirring unit 208 so as to penetrate the side wall including the surface 208c in the thickness direction. A cylindrical rod-like member provided so as to be inserted through 221 and rotated about an axis by a motor (not shown). The rotating disk 219 is a disk-shaped member that is supported by the rotating shaft member 218 so that its axis coincides with the axis of the rotating shaft member 218 and rotates as the rotating shaft member 218 rotates. The plurality of stirring blades 220 are supported by the peripheral portion of the turntable 219 and rotate as the turntable 219 rotates.

  In the coating step S3, the peripheral speed of the outermost periphery of the rotary stirring means 204 is preferably set to 30 m / sec or more, and more preferably set to 50 m / sec or more. The outermost periphery of the rotary stirring means 204 is a portion 204a of the rotary stirring means 204 having the longest distance from the axis of the rotary shaft member 218 in the direction perpendicular to the direction in which the rotary shaft member 218 of the rotary stirring means 204 extends. By setting the peripheral speed at the outermost periphery of the rotating stirring means 204 at the time of rotation to 30 m / sec or more, the resin fine particle-adhering mother particles can be isolatedly flowed. If the peripheral speed at the outermost periphery is less than 30 m / sec, the resin fine particle-adhered mother particles cannot be isolated and cannot be uniformly coated with the resin film.

  It is preferable that the resin fine particle-adhered mother particles collide with the rotating disk 219 vertically. As a result, the resin fine particle-adhered mother particles are sufficiently stirred, so that the toner mother particles can be more uniformly coated with the mixed resin fine particles, and the uniform toner yield of the coating layer can be further improved.

(Spraying means)
The spray means 203 is provided so as to be inserted into an opening formed in the outer wall of the powder flow path 202, and in the powder flow part 209, the powder closest to the opening part 211 in the flow direction of the resin fine particle-attached mother particles. It is provided in the body flow part. The spraying unit 203 applies a mixture obtained by mixing a liquid and a carrier gas, a carrier gas supply unit for supplying a liquid, a carrier gas supply unit for supplying a carrier gas, and the toner base particles present in the powder channel 202 to the toner base particles. And a two-fluid nozzle that sprays liquid droplets onto the toner base particles. Compressed air or the like can be used as the carrier gas. The liquid fed to the spraying means 203 at a constant flow rate by the liquid feed pump, and the liquid sprayed by the spraying means 203 is gasified, and the gasified liquid spreads on the surfaces of the toner base particles and the mixed resin fine particles. As a result, the toner base particles and the mixed resin fine particles are plasticized.

(Temperature adjustment jacket)
A temperature adjusting jacket (not shown), which is a temperature adjusting means, is provided in at least a part of the outside of the powder flow path 202, and rotates and stirs in the powder flow path 202 through a cooling medium or a heating medium in the space inside the jacket. 204 is adjusted to a predetermined temperature. As a result, in the temperature adjusting step S3b described later, the temperature inside the powder flow path and outside the rotary stirring means can be controlled to a temperature at which the toner base particles and the mixed resin fine particles are not softened and deformed. Further, in the spraying step S3c and the film forming step S3d, it is possible to reduce variations in temperature applied to the toner base particles, the mixed resin fine particles, and the liquid, and to maintain a stable fluid state of the resin fine particle-adhered base particles.

  In the present embodiment, the temperature adjustment jacket is preferably provided on the entire outside of the powder flow path 202. The resin fine particle adhering mother particles usually collide with the inner wall of the powder flow channel many times, but at the time of the collision, part of the collision energy is converted into thermal energy and accumulated in the toner mother particles and the mixed resin fine particles. As the number of collisions increases, the thermal energy accumulated in these particles increases, and the toner base particles and the mixed resin fine particles are eventually softened and adhere to the inner wall of the powder flow path. By providing the temperature adjustment jacket on the entire outside of the powder flow path 202, the adhesion force of the toner base particles and the mixed resin fine particles to the inner wall of the powder flow path is reduced, and the powder flow path 202 due to a sudden rise in the temperature in the apparatus. It is possible to reliably prevent the toner base particles from adhering to the inner wall, and to prevent the inside of the powder channel from becoming narrow due to the toner base particles and the mixed resin fine particles. Therefore, the toner mother particles are uniformly coated with the mixed resin fine particles, and a toner having excellent cleaning properties can be produced with a high yield.

  Moreover, in the powder flow part 209 downstream from the spraying means 203, the sprayed liquid does not dry and remains, and if the temperature is not appropriate, the drying speed becomes slow and the liquid tends to stay. When the toner base particles come into contact with this, the toner base particles are likely to adhere to the inner wall of the powder flow path 202, and become a toner aggregation generation source. On the inner wall in the vicinity of the opening 210, the resin fine particle adhering mother particles flowing into the agitating part 208 collide with the resin fine particle adhering mother particles flowing in the agitating part 208 by the stirring by the rotary stirring means 204, and the collided toner mother particles. Tends to adhere to the vicinity of the opening 210. Therefore, by providing the temperature adjustment jacket at the portion where the toner base particles are likely to adhere, the toner base particles can be more reliably prevented from adhering to the inner wall of the powder flow path 202.

(Powder input part and powder recovery part)
A powder input unit 206 and a powder recovery unit 207 are connected to the powder flow unit 209 of the powder channel 202. FIG. 4 is a side view showing the configuration around the powder input unit 206 and the powder recovery unit 207.

  The powder input unit 206 includes a hopper (not shown) that supplies resin fine particle-adhering mother particles, a supply pipe 212 that communicates the hopper and the powder flow path 202, and an electromagnetic valve 213 provided in the supply pipe 212. Resin particulate adhering mother particles supplied from the hopper are supplied to the powder flow path 202 through the supply pipe 212 in a state where the flow path in the supply pipe 212 is opened by the electromagnetic valve 213. Resin fine particle adhering mother particles supplied to the powder flow path 202 flow in a constant powder flow direction by stirring by the rotary stirring means 204. Further, in the state where the flow path in the supply pipe 212 is closed by the electromagnetic valve 213, the resin fine particle-adhered mother particles are not supplied to the powder flow path 202.

  The powder recovery unit 207 includes a recovery tank 215, a recovery pipe 216 that communicates the recovery tank 215 and the powder flow path 202, and an electromagnetic valve 217 provided in the recovery pipe 216. In a state where the flow path in the collection pipe 216 is opened by the electromagnetic valve 217, the toner particles flowing through the powder flow path 202 are collected in the collection tank 215 via the collection pipe 216. In addition, when the flow path in the collection pipe 216 is closed by the electromagnetic valve 217, the toner particles flowing through the powder flow path 202 are not collected.

(3) -2 Temperature adjustment step S3b
In the temperature adjustment step S3b, while rotating the rotary stirring means 204, the temperature inside the powder flow path 202 and the rotary stirring means 204 are adjusted to a predetermined temperature through a medium through jackets for temperature adjustment disposed outside them. As a result, the temperature in the powder flow path 202 can be controlled to be equal to or lower than the temperature at which the resin fine particle adhering mother particles introduced in the spraying step S3c described later are not softened and deformed.

(3) -3 Spraying step S3c
In the spraying step S3c, a liquid having an effect of plasticizing the resin fine particle adhering mother particles in a fluidized state without dissolving them is sprayed from the spray means 203 by the carrier gas.

  In the state where the rotating shaft member 218 of the rotating stirring means 204 is rotating, the resin fine particle-adhering mother particles are supplied from the powder charging unit 206 to the powder channel 202. The resin fine particle adhering mother particles supplied to the powder flow path 202 are stirred by the rotary stirring means 204 and flow in the direction of the arrow 214 through the powder flow section 209 of the powder flow path 202.

  The sprayed liquid is preferably gasified so that the inside of the powder passage 202 has a constant gas concentration, and the gasified liquid is preferably discharged out of the powder passage through the through hole 221. Thereby, the concentration of the gasified liquid in the powder channel 202 can be kept constant, and the drying speed of the liquid can be increased as compared with the case where the concentration is not kept constant. Therefore, it is possible to prevent toner particles in which undried liquid remains from adhering to other toner particles, suppress aggregation of the toner particles, and further improve the yield of toner particles having a uniform coating layer.

  The concentration of the gasified liquid measured by the concentration sensor in the gas discharge unit 222 is preferably about 3% or less. When the concentration is about 3% or less, the drying speed of the liquid can be sufficiently increased, toner particles in which undried liquid remains can be prevented from adhering to other toner particles, and aggregation of the toner particles can be prevented. Further, the concentration of the gasified liquid is more preferably 0.1% or more and 3.0% or less. When the spraying speed is within such a range, aggregation of toner particles can be prevented without reducing productivity.

  In the present embodiment, it is preferable to start spraying after the flow rate of the resin fine particle-adhering mother particles is stabilized in the powder flow path 202. As a result, the liquid can be uniformly sprayed onto the resin fine particle-adhered mother particles, and the yield of the toner having a uniform coating layer can be improved.

  The liquid that has the effect of plasticizing the toner base particles and the mixed resin fine particles without dissolving them is not particularly limited. However, since the liquid needs to be removed from the toner base particles and the mixed resin fine particles after the liquid is sprayed, it easily evaporates. It is preferably a liquid. Examples of such a liquid include a liquid containing a lower alcohol. Examples of the lower alcohol include methanol, ethanol, propanol and the like. If the liquid contains such a lower alcohol, the wettability of the mixed resin fine particles as the coating material to the toner mother particles can be improved, and the mixed resin fine particles adhere to the entire surface or most of the toner mother particles, and further deformed. And it becomes easy to form a film. Further, since the lower alcohol has a high vapor pressure, the drying time for removing the liquid can be further shortened, and aggregation of the toner particles can be suppressed.

  The viscosity of the sprayed liquid is preferably 5 cP or less. The viscosity of the liquid is measured at 25 ° C., and can be measured by, for example, a cone plate type rotary viscometer. Alcohol is preferable as a liquid having a viscosity of 5 cP or less. Examples of the alcohol include methyl alcohol and ethyl alcohol. Since these alcohols have a low viscosity and are easy to evaporate, the liquid sprayed from the spraying means 203 does not coarsen the liquid droplet diameter of the liquid sprayed from the spraying means 203, so that the liquid having a fine droplet diameter can be obtained. Spraying becomes possible. In addition, it is possible to spray a liquid having a uniform droplet diameter. At the time of collision between the toner base particles and the liquid droplets, further refinement of the liquid droplets can be promoted. As a result, the surface of the toner base particles and the mixed resin fine particles can be uniformly wetted and blended, and the mixed resin fine particles can be softened by a synergistic effect with the collision energy. As a result, a coated toner having excellent uniformity can be obtained.

  An angle θ formed between the liquid spraying direction which is the axial direction of the two-fluid nozzle of the spraying means 203 and the powder flow direction which is the flow direction of the resin fine particle adhering mother particles in the powder channel 202 is 0 ° or more and 45 ° or less. It is preferable that When θ is within such a range, liquid droplets are prevented from recoiling on the inner wall of the powder flow path 202, and the yield of the coated toner can be further improved. When the angle θ exceeds 45 °, the liquid droplet recoils on the inner wall of the powder flow path 202, the liquid tends to stay, the toner particles agglomerate, and the yield deteriorates.

  The spreading angle φ of the liquid sprayed by the spraying means 203 is preferably 20 ° or more and 90 ° or less. If the spread angle φ is out of this range, it may be difficult to uniformly spray the liquid onto the resin fine particle-adhered mother particles.

(3) -4 Membrane formation step S3d
In the film forming step S3d, the rotating fine stirring means 204 is continuously stirred at a predetermined temperature until the mixed resin fine particles adhering to the toner base particles are softened and formed into a film, and the resin fine particle attached mother particles are caused to flow, and the toner base particles in the resin layer Coating.

(3) -5 Recovery step S3e
In the collection step S3e, the liquid spray from the spray unit and the rotation of the rotary stirring unit 204 are stopped, and the capsule toner is discharged from the powder recovery unit 207 to the outside and recovered.

  The toner manufacturing apparatus 201 is not limited to the above configuration, and various modifications can be made. For example, the temperature adjustment jacket may be provided on the entire outer surface of the powder flow part 209 and the stirring part 208, or may be provided on a part of the powder flow part 209 or the outside of the stirring part 208. . When the temperature adjustment jacket is provided on the entire surface outside the powder flow section 209 and the stirring section 208, it is possible to more reliably prevent the toner base particles from adhering to the inner wall of the powder flow path 202.

  Further, the toner manufacturing apparatus can be configured by combining a commercially available stirring apparatus and spraying means. As a commercially available stirring apparatus provided with a powder flow path and rotating stirring means, for example, a hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.) and the like can be mentioned. By mounting a liquid spray unit in such a stirring device, this stirring device can be used as a toner manufacturing apparatus used for manufacturing the capsule toner of the present invention.

2. Toner A capsule toner according to an embodiment of the present invention is manufactured by the above-described toner manufacturing method. The capsule toner obtained by the above-described toner production method is excellent in durability and storage stability because a constituent component of the toner base particles is protected by forming a resin coating layer on the surface of the toner base particles. Further, when such a capsule toner is used for image formation, a high-definition and good-quality image without uneven density can be obtained.

  An external additive may be added to the capsule toner of the present invention. Known external additives can be used, and examples thereof include silica and titanium oxide. These are preferably surface-treated with a silicon resin, a silane coupling agent or the like. The amount of the external additive used is preferably 1 to 10 parts by weight with respect to 100 parts by weight of the capsule toner.

3. Developer The developer according to the embodiment of the present invention includes the capsule toner according to the above-described embodiment. The developer of this embodiment can be used as a one-component developer or a two-component developer. When used as a one-component developer, the toner is used alone without using a carrier. In addition, using a blade and a fur brush, the toner is conveyed by frictional charging with the developing sleeve and the toner is deposited on the sleeve, thereby forming an image. When used as a two-component developer, the capsule toner of the above embodiment is used together with a carrier.

  As the carrier, a known carrier can be used, for example, a resin-coated carrier in which a single or composite ferrite and carrier core particles made of iron, copper, zinc, nickel, cobalt, manganese, chromium and the like are coated with a coating substance, or Examples thereof include a resin-dispersed carrier in which magnetic particles are dispersed in a resin.

  Known coating materials can be used, such as polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicon resin, polyester resin, metal compound of ditertiary butylsalicylic acid, styrene resin, acrylic resin , Polyamide, polyvinyl butyral, nigrosine, amino acrylate resin, basic dye, basic dye lake, silica fine powder, alumina fine powder, and the like. The resin used for the resin-dispersed carrier is not particularly limited, and examples thereof include styrene acrylic resin, polyester resin, fluorine resin, and phenol resin. Either of them is preferably selected according to the toner component, and one type can be used alone, or two or more types can be used in combination.

The shape of the carrier is preferably a spherical shape or a flat shape. The particle size of the carrier is not particularly limited, but is preferably 10 to 100 μm, more preferably 20 to 50 μm, considering high image quality. Furthermore, the resistivity of the carrier is preferably 10 ⁸ Ω · cm or more, more preferably 10 ¹² Ω · cm or more.

The volume resistivity of the carrier is determined by placing carrier particles in a container having a cross-sectional area of 0.50 cm ² and tapping, then applying a load of 1 kg / cm ² to the particles packed in the container and placing the load between the load and the bottom electrode. It is a value obtained from a current value when a voltage generating an electric field of 1000 V / cm is applied. When the resistivity is low, the carrier is charged when a bias voltage is applied to the developing sleeve, and the carrier particles easily adhere to the photoreceptor. Further, breakdown of the bias voltage is likely to occur.

  The magnetization strength (maximum magnetization) of the carrier is preferably 10 to 60 emu / g, more preferably 15 to 40 emu / g. Under a general developing roller magnetic flux density condition, if it is less than 10 emu / g, the magnetic binding force does not work, which may cause carrier scattering. On the other hand, if the magnetization strength exceeds 60 emu / g, the carrier spikes become too high in the non-contact development, and it becomes difficult to maintain the non-contact state between the image carrier and the toner. Further, in the contact development, there is a risk that a sweep is likely to appear in the toner image.

The use ratio of the toner and the carrier in the two-component developer is not particularly limited, and can be appropriately selected according to the kind of the toner and the carrier. For example, when mixed with a resin-coated carrier (density 5 to 8 g / cm ² ), the toner may be contained in an amount of 2 to 30% by weight, preferably 2 to 20% by weight based on the total amount of developer. Further, the coverage of the carrier with the toner is preferably 40 to 80%.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In the following, “parts” and “%” mean “parts by weight” and “% by weight” unless otherwise specified. In Examples and Comparative Examples, the glass transition temperature and softening temperature of the resin, the melting point of the release agent, the volume average particle diameter and coefficient of variation of the toner base particles, and the volume average particle diameter of the resin fine particles were measured as follows.

[Glass transition temperature of resin]
Using a differential scanning calorimeter (trade name: DSC220, manufactured by Seiko Denshi Kogyo Co., Ltd.), according to Japanese Industrial Standard (JIS) K7121-1987, 1 g of a sample is heated at a heating rate of 10 ° C. per minute and a DSC curve is measured. did. In the obtained DSC curve, the slope is maximized with respect to the straight line obtained by extending the base line on the high temperature side to the low temperature side from the endothermic peak corresponding to the glass transition, and the curve from the rising part of the peak to the vertex. The temperature at the intersection with the drawn tangent was defined as the glass transition temperature (Tg).

[Softening temperature of resin]
Using a flow characteristic evaluation apparatus (trade name: Flow Tester CFT-100C, manufactured by Shimadzu Corporation), 1 g of a sample was heated at a heating rate of 6 ° C. per minute, and a load of 20 kgf / cm ² (9.8 × 10 ⁵ Pa). And the temperature at which half of the sample flowed out from the die (nozzle diameter 1 mm, length 1 mm) was determined, and was defined as the softening temperature (Tm).

[Melting point of release agent]
Using a differential scanning calorimeter (trade name: DSC220, manufactured by Seiko Denshi Kogyo Co., Ltd.), 1 g of a sample is heated from a temperature of 20 ° C. to 200 ° C. at a heating rate of 10 ° C. per minute, and then rapidly cooled from 200 ° C. to 20 ° C. The operation was repeated twice and the DSC curve was measured. The temperature of the endothermic peak corresponding to the melting of the DSC curve measured in the second operation was taken as the melting point of the release agent.

[Volume average particle diameter and coefficient of variation of toner base particles]
20 ml of a sample and 1 ml of sodium alkyl ether sulfate are added to 50 ml of an electrolytic solution (trade name: ISOTON-II, manufactured by Beckman Coulter, Inc.), and an ultrasonic dispersion device (trade name: desktop type dual frequency ultrasonic cleaner VS-D100). , Manufactured by ASONE Co., Ltd.) for 3 minutes at a frequency of 20 kHz to obtain a measurement sample. This sample for measurement was measured using a particle size distribution measuring device (trade name: Multisizer 3, manufactured by Beckman Coulter, Inc.) under the conditions of aperture diameter: 100 μm, number of measured particles: 50000 count, and volume particle size distribution of sample particles. Were used to determine the standard deviation in volume average particle size and volume particle size distribution. The coefficient of variation (CV value,%) was calculated based on the following formula.
CV value (%) = (standard deviation in volume particle size distribution / volume average particle diameter) × 100

[Volume average particle diameter of resin fine particles]
[Volume average particle diameter of resin fine particles]
The particle size distribution is measured using a particle size distribution measuring apparatus (Microtrack MT3000 manufactured by Nikkiso Co., Ltd.), and from the volume particle size distribution of the sample particles as a dispersion medium: refractive index 1.33 (water) and dispersoid: refractive index 1.49. The volume average particle size was determined.

Example 1
[Toner mother particle production step S1]
Polyester resin (Kao Corporation, glass transition temperature 60 ° C, softening temperature 138 ° C)
85 parts Colorant (CI Pigment Blue 15: 3) 5 parts Release agent (trade name: Carnauba wax, Toa Kasei Co., Ltd., melting point 82 ° C.) 8 parts Charge control agent (trade name: Bontron E84, Orient Chemical Industry Co., Ltd.) 2nd part

  The above raw materials were premixed for 3 minutes with a Henschel mixer and then melt-kneaded using a twin-screw extruder (trade name: PCM-30, manufactured by Ikegai Co., Ltd.). The melt-kneaded product is cooled by a cooling belt, coarsely pulverized by a speed mill having a φ2 mm screen, finely pulverized by a jet type pulverizer (trade name: IDS-2, manufactured by Nippon Pneumatic Industry Co., Ltd.), and The toner was classified with an elbow jet classifier (trade name, manufactured by Nippon Steel & Mining Co., Ltd.) to produce toner base particles having a volume average particle size of 6.9 μm, a coefficient of variation of 22%, a glass transition temperature of 60 ° C., and a softening temperature of 120 ° C.

[Resin fine particle preparation step S2]
<Preparation of polyester resin fine particles A>
Polyester resin A was dissolved in methyl ethyl ketone, and this solution was mixed with 1N aqueous ammonia solution and emulsified with a mechanical disperser (trade name: CLEARMIX, manufactured by M Technique Co., Ltd.). Methyl ethyl ketone was distilled off from the resulting emulsion under reduced pressure to obtain polyester resin fine particles A (glass transition temperature 60 ° C., softening temperature 110 ° C.) having a volume average particle size of 0.16 μm.

<Preparation of styrene-acrylic copolymer resin fine particles B>
Styrene, acrylic acid and butyl acrylate are polymerized to produce styrene-acrylic acid-butylacrylic acid copolymer resin particles B (glass transition temperature 64 ° C., softening temperature 120 ° C.) having a volume average particle size of 0.15 μm. Obtained.

[Coating step S3]
<Preparation of resin fine particles>
A suspension of polyester resin fine particles A and styrene-acrylic copolymer resin fine particles B, 10 wt% suspension adjusted so that polyester resin fine particles A are 1 part by weight and styrene-acrylic copolymer resin fine particles B are 9 parts by weight. The liquid was dried with a spray dryer to obtain mixed resin particles.

  When the polyester resin fine particles A are obtained singly or when the styrene-acrylic copolymer resin fine particles B are obtained singly, each 10 wt% suspension is dried with a spray dryer to obtain resin particles. It was.

  A hybrid system equivalent to the apparatus shown in FIG. 2 (trade name: NHS-1 type, manufactured by Nara Machinery Co., Ltd.) and an apparatus in which a two-fluid nozzle is attached to 100 parts of toner base particles and a volume average particle size of 0. Mixed resin fine particles consisting of 7 parts of 10 μm styrene-acrylic copolymer resin fine particles A and 3 parts of polyester resin fine particles B having a volume average particle diameter of 0.10 μm were charged and allowed to stay at a rotational speed of 8000 rpm for 10 minutes.

  As the liquid spraying unit, a unit in which a liquid feed pump (trade name: SP11-12, manufactured by FROM Co., Ltd.) and a two-fluid nozzle are connected so as to enable quantitative liquid feeding can be used. The spraying speed of liquid and the discharge speed of liquid gas can be observed using a commercially available gas detector (trade name: XP-3110, manufactured by Shin Cosmos Electric Co., Ltd.).

  The temperature adjusting jacket was provided on the entire surface of the powder flow section and the stirring section wall. A temperature sensor was attached to the powder channel, and the temperature of the powder flow part and the stirring part was adjusted to 45 ° C. In the apparatus, the peripheral speed at the outermost periphery of the rotating stirring means of the hybridization system was set to 100 m / sec in the mixed resin fine particle adhering step to the toner base particle surface. The peripheral speed was also 100 m / sec in the spraying step and the film forming step. The mounting angle of the two-fluid nozzle was set so that the angle formed between the liquid spraying direction and the powder flow direction (hereinafter referred to as “spraying angle”) was parallel (0 °).

  Ethanol was sprayed at a spray rate of 0.5 g / min and an air flow rate of 5 L / min for 40 minutes to form the mixed resin fine particles A on the surface of the toner base particles. After stopping the ethanol spraying, the mixture was stirred for 5 minutes to obtain the capsule toner of Example 1 (volume average particle ratio 7.2 μm, variation coefficient 25%). At this time, the discharge concentration of the liquid discharged through the through hole and the gas discharge portion was stable at about 1.4 Vol%. Moreover, the air flow rate sent into the apparatus was adjusted to 5 L / min, and the total air flow rate from the two-fluid nozzle was 10 L / min.

<Preparation of two-component developer>
The toner of Example 1 and a ferrite core carrier having a volume average particle diameter of 60 μm were mixed so that the toner concentration would be 7% to prepare the two-component developer of Example 1.

(Example 2)
Example except that mixed resin fine particles composed of 5 parts of styrene-acrylic copolymer resin fine particles A having a volume average particle diameter of 0.10 μm and 5 parts of polyester resin fine particles B having a volume average particle diameter of 0.10 μm were used. In the same manner as in Example 1, a toner of Example 2 was obtained. The toner of Example 2 had a volume average particle size of 7.1 μm and a coefficient of variation of 26%.

(Example 3)
Example except that mixed resin fine particles composed of 3 parts of styrene-acrylic copolymer resin fine particles A having a volume average particle diameter of 0.10 μm and 7 parts of polyester resin fine particles B having a volume average particle diameter of 0.10 μm were used. In the same manner as in Example 1, a toner of Example 3 was obtained. The toner of Example 3 had a volume average particle size of 7.1 μm and a coefficient of variation of 28%.

Example 4
Example except that 7 parts of styrene-acrylic copolymer resin fine particles A (single) having a volume average particle diameter of 0.10 μm and 3 parts of polyester resin fine particles B (single) were used instead of the mixed resin fine particles. In the same manner as in Example 1, a toner of Example 4 was obtained. The toner of Example 4 had a volume average particle diameter of 7.1 μm and a coefficient of variation of 28%.

(Example 5)
In place of mixed resin fine particles, 5 parts of styrene-acrylic copolymer resin fine particles A (single) having a volume average particle diameter of 0.10 μm and 5 parts of polyester resin fine particles B (single) having a volume average particle diameter of 0.10 μm A toner of Example 5 was obtained in the same manner as in Example 1 except that was used. The toner of Example 5 had a volume average particle size of 7.1 μm and a coefficient of variation of 26%.

(Example 6)
Instead of mixed resin fine particles, 3 parts of styrene-acrylic copolymer resin fine particles A (single) having a volume average particle diameter of 0.10 μm and 7 parts of polyester resin fine particles B (single) having a volume average particle diameter of 0.10 μm A toner of Example 6 was obtained in the same manner as Example 1 except that was used. The toner of Example 6 had a volume average particle size of 7.1 μm and a coefficient of variation of 28%.

(Example 7)
Example 1 except that mixed resin fine particles composed of 5 parts of styrene-acrylic copolymer resin fine particles A having a volume average particle diameter of 0.10 μm and 5 parts of polyester resin fine particles B having a volume average particle diameter of 0.08 μm were used. In the same manner as described above, a toner of Example 7 was obtained. The toner of Example 7 had a volume average particle size of 7.1 μm and a coefficient of variation of 26%.

(Example 8)
Example 1 except that mixed resin fine particles comprising 5 parts of styrene-acrylic copolymer resin fine particles A having a volume average particle diameter of 0.10 μm and 5 parts of polyester resin fine particles B having a volume average particle diameter of 0.12 μm were used. In the same manner as described above, a toner of Example 8 was obtained. The toner of Example 8 had a volume average particle size of 7.1 μm and a coefficient of variation of 26%.

Example 9
Example 1 except that mixed resin fine particles composed of 5 parts of styrene-acrylic copolymer resin fine particles A having a volume average particle diameter of 0.10 μm and 5 parts of polyester resin fine particles B having a volume average particle diameter of 0.07 μm were used. In the same manner as described above, the toner of Example 9 was obtained. The toner of Example 9 had a volume average particle diameter of 7.1 μm and a coefficient of variation of 27%.

(Example 10)
Example 1 except that mixed resin fine particles comprising 5 parts of styrene-acrylic copolymer resin fine particles A having a volume average particle diameter of 0.10 μm and 5 parts of polyester resin fine particles B having a volume average particle diameter of 0.13 μm were used. In the same manner as described above, the toner of Example 10 was obtained. The toner of Example 10 had a volume average particle diameter of 7.2 μm and a coefficient of variation of 26%.

(Comparative Example 1)
Comparative Example 1 was obtained by forming only the toner base particles without forming the resin coating layer. The toner of Comparative Example 2 had a volume average particle size of 6.9 μm and a coefficient of variation of 22%.

(Comparative Example 2)
A toner of Comparative Example 2 was obtained in the same manner as in Example 1 except that the styrene-acrylic copolymer resin fine particles A were not added and the polyester resin fine particles B having a volume average particle size of 0.10 μm were changed to 10 parts. . The toner of Comparative Example 2 had a volume average particle diameter of 7.1 μm and a coefficient of variation of 29%.

(Comparative Example 3)
A toner of Comparative Example 3 was obtained in the same manner as in Example 1 except that the polyester resin fine particles B were not added and the styrene acrylic copolymer resin fine particles A having a volume average particle size of 0.10 μm were changed to 10 parts. . The toner of Comparative Example 3 had a volume average particle size of 7.2 μm and a coefficient of variation of 25%.

The toners of Examples 1 to 10 and Comparative Examples 1 to 3 were evaluated as follows.
[Blocking resistance]
A commercial copier (trade name: MX-2300G, manufactured by Sharp Corporation) was filled with the two-component developers of Examples 1 to 10 and Comparative Examples 1 to 3, respectively, and adjusted so that the image was not developed on the photoreceptor. In this state, only the developing machine was continuously operated for 5 hours at a constant temperature of 20 ° C. to confirm the presence or absence of aggregates. The evaluation criteria for blocking resistance are as follows.
○ (Good): No occurrence of aggregates △ (Normal): Little occurrence of aggregates × (Poor): Many occurrences of aggregates

[Hot offset resistance]
Each of the above-described copying machines is filled with the two-component developers of Examples 1 to 10 and Comparative Examples 1 to 3, and the surface temperature of the heating roller is increased from 130 ° C. to 220 ° C. in 5 ° C. increments to form an image. The lower limit temperature at which low temperature offset does not occur is the minimum fixing temperature, the upper limit temperature at which high temperature offset does not occur is the maximum fixing temperature, and the difference between the maximum fixing temperature and the minimum fixing temperature is the non-offset region.

The hot offset resistance was evaluated as follows from the value of the non-offset region.
○ (Good): Non-offset region is 30 ° C or higher △ (Normal): Non-offset region is 25 ° C
X (defect): non-offset region is 20 ° C or less

[Comprehensive evaluation]
Together with the evaluation results of blocking resistance and hot offset resistance, comprehensive evaluation was performed according to the following criteria.
○ (good): all results are ○ Δ (normal): any is Δ × (bad): any is × The two-component developers of Examples 1 to 10 and Comparative Examples 1 to 3 Table 1 shows the evaluation results for

  In Examples 1 to 10 in which the resin coating layer includes a polyester resin and a styrene-acrylic copolymer resin, the anti-blocking property was improved without significantly impairing the hot offset resistance.

  In Comparative Example 2, since the resin coating layer was composed only of the polyester resin, the hot offset resistance was improved, but the encapsulation effect by the resin coating layer was weak and the blocking resistance was inferior. In Comparative Example 3, since the resin coating layer is composed only of the styrene-acrylic copolymer resin, the blocking resistance was improved, but the seepage of the release agent was hindered and the hot offset resistance was impaired. It was.

  In Comparative Example 1, since the resin coating layer was not formed, the hot offset resistance was not impaired, but the blocking resistance was deteriorated.

DESCRIPTION OF SYMBOLS 201 Toner manufacturing apparatus 202 Powder flow path 203 Spraying means 204 Rotating stirring means 206 Powder input part 207 Powder recovery part 220 Stirring blade

Claims (5)

Toner base particles containing a binder resin, a release agent and a colorant;
A capsule toner comprising: a polyester resin and a styrene-acrylic copolymer resin; and a resin coating layer that covers a surface of the toner base particles. Mixed resin fine particles composed of polyester resin fine particles and styrene-acrylic copolymer resin fine particles are adhered to the surface of toner mother particles containing a binder resin, a release agent and a colorant to form resin fine particle-adhered mother particles. Resin fine particle adhesion process;
A spraying step of spraying a liquid that plasticizes the mixed resin fine particles and the toner mother particles, wherein the resin fine particle-attached mother particles are in a fluid state;
And a film forming step of forming a resin coating layer on the surface of the toner base particles by forming the mixed resin fine particles into a film by an impact force. The mixed resin fine particle adhesion step includes:
Mixing the polyester resin fine particles and the styrene-acrylic copolymer resin fine particles to prepare mixed resin fine particles;
3. The method according to claim 2, further comprising the step of mixing the toner base particles and the mixed resin fine particles to form resin fine particle-adhered mother particles in which the mixed resin fine particles adhere to the surface of the toner mother particles. A method for producing a capsule toner. The capsule according to claim 2 or 3, wherein the volume average particle diameter Dp of the polyester resin fine particles and the volume average particle diameter Ds of the styrene-acrylic copolymer resin fine particles satisfy the following formula (1). Toner manufacturing method.
Ds × 0.8 ≦ Dp ≦ Ds × 1.2 (1)   The method for producing a capsule toner according to claim 3 or 4, wherein the mixed resin fine particles contain 30% by weight or more and 70% by weight or less of the polyester resin fine particles.

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