JP2012128040A - Production method of capsule toner and capsule toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a capsule toner using toner base particles and resin fine particles, by which resin fine particles are sufficiently disintegrated to suppress generation of white spots in a fixed image, and to provide the capsule toner.SOLUTION: The production method of a capsule toner includes a cooling step, an adhering step and a filming step. In the cooling step, resin fine particles are cooled to a temperature equal to or lower than the brittleness temperature. In the adhering step, the resin fine particles cooled in the cooling step is fed as kept at the temperature equal to or lower than the brittleness temperature into a powder flow passage where the toner base particles flow, and the toner particles and the resin fine particles are mixed while stirring to adhere the resin fine particles to the surfaces of the toner base particles to obtain toner base particles with resin fine particles. In the filming step, stirring is continued until the resin fine particles on the surfaces of the toner base particles with resin fine particles form a film so as to form a resin coating layer on the surfaces of the toner base particles.

Description

  The present invention relates to a capsule toner manufacturing method and a capsule toner.

  In an image forming apparatus using an electrophotographic system, an image is formed through, for example, charging, exposure, development, transfer, cleaning, static elimination, and fixing processes. In the charging process, the surface of the photoconductor to be rotated is uniformly charged by the charging device. In the exposure process, the charged photoconductor surface is irradiated with laser light by the exposure device, and an electrostatic latent image is formed on the surface of the photoconductor. Is done. Next, in the developing step, the electrostatic latent image on the surface of the photoconductor is developed by the developer supplied from the developing device, and a toner image made of toner is formed on the surface of the photoconductor. The toner image formed on the surface of the photoreceptor is transferred to a recording medium by a transfer device in a transfer process, and then fixed to the recording medium in a fixing process. Further, the transfer residual toner remaining on the surface of the photoconductor after the image forming operation is removed by a cleaning device in a cleaning process and collected in a predetermined recovery unit, and the residual charge on the surface of the photoconductor after cleaning is removed in a static elimination process. In order to prepare for the next image formation, the charge is removed by the charge removal device. The transfer of the toner image to the recording medium may be performed via an intermediate transfer medium.

  Examples of the developer include a one-component developer composed only of toner and a two-component developer composed of toner and carrier. The toner needs to have functions required not only in the development process but also in each of the transfer process, the fixing process, and the cleaning process.

  Examples of the fixing method of the toner image in the fixing step include a heat roll fixing method in which a heat roll is used as a heating medium for heating and melting the toner constituting the toner image. The fixing device used in the heat roll fixing method has a simple configuration, and an image fixed by the heat roll fixing method has good image quality.

  In order to achieve energy saving in the fixing by the heat roll fixing method, it is necessary to melt the toner constituting the toner image at the lowest possible temperature and fix it on the recording medium. Therefore, there is a demand for a toner that can be fixed at a low temperature, and the softening temperature of the toner is lowered by a method such as using a resin having a low molecular weight as a binder resin to be contained in the toner or adding a release agent to the toner. It realizes a toner that can be fixed at low temperature.

  However, such a toner has a problem in that, for example, in a high temperature environment, the toner is softened and agglomerated to reduce the blocking resistance.

  In order to solve such a problem, Patent Document 1 discloses a toner obtained by an emulsion aggregation method, which includes toner base particles containing a crystalline polyester resin and a resin coating layer that covers the surface of the toner base particles. Thus, a toner in which the main component of the resin coating layer is an amorphous resin is disclosed. According to the toner disclosed in Patent Document 1, since the crystalline toner is contained in the toner base particles, the low-temperature fixability is good and the surface of the toner base particles is coated with the resin coating layer. Deterioration can be suppressed.

  However, since the toner disclosed in Patent Document 1 is produced by an emulsion aggregation method, it is necessary to sufficiently remove the water used as the dispersant and the solvent used in the production from the inside of the toner. There is a problem that it takes time and the manufacturing cost becomes high. If the dispersant and water remain inside the toner, charging performance and environmental performance are deteriorated.

  Here, in Patent Document 2, the toner base particles and the resin fine particles are agitated and mixed by a mixer to adhere the resin fine particles to the surface of the toner base particles, and then mechanically applied to the toner base particles to which the resin fine particles are attached. A method for producing toner is disclosed in which resin fine particles are fixed to the surface of toner base particles by applying an impact force.

  When a toner is produced by an emulsion aggregation method using toner base particles containing a crystalline polyester resin and resin fine particles made of an amorphous resin, and the toner is produced by the toner production method disclosed in Patent Document 2. Thus, it is possible to obtain a toner that has good low-temperature fixability and can suppress a decrease in blocking resistance.

JP 2005-266565 A Japanese Patent Laid-Open No. 5-281787

  However, when the toner obtained in this way is used for image formation, white spots appear in the fixed image, which may deteriorate the image quality. The cause of white spots is relatively large aggregated resin particles. The resin fine particles are in an aggregated state before being charged into the mixer. However, in the toner manufacturing method disclosed in Patent Document 2, even if the resin fine particles are stirred and mixed with the toner mother particles in the mixer, the resin in the aggregated state is used. If the fine particles cannot be sufficiently crushed and the resin fine particles remaining in an agglomerated state are relatively large, white spots appear in the fixed image.

  An object of the present invention is a capsule toner manufacturing method using toner base particles and resin fine particles, which can sufficiently prevent the generation of white spots in a fixed image by sufficiently crushing the resin fine particles. A manufacturing method and a capsule toner are provided.

The present invention is a cooling step of cooling the resin fine particles to a temperature below the embrittlement temperature;
In the rotary stirring device comprising a rotary stirring means and a powder flow path, the resin fine particles cooled in the cooling step in a powder flow path in which toner base particles containing a binder resin and a colorant are flowing The toner base particles and the resin fine particles are mixed under stirring while the temperature is maintained below the embrittlement temperature, and the resin fine particles are adhered to the surface of the toner base particles. An attaching step for obtaining attached toner mother particles;
And a film forming step of forming a resin coating layer on the surface of the toner base particles by continuing stirring until the resin fine particles on the surface of the toner base particles are formed into a film. It is a manufacturing method.

  Further, the present invention is characterized in that the resin fine particles include a crystalline resin and an amorphous resin.

  In the cooling step, the resin fine particles cooled to a temperature not higher than the embrittlement temperature are transported to the powder flow channel by a carrier gas having a temperature not higher than the embrittlement temperature, It is characterized by being introduced into

  In the cooling step, the resin fine particles are cooled to a temperature below the embrittlement temperature by a coolant.

  Further, the present invention is characterized in that liquid nitrogen or an evaporated gas thereof is used as the coolant.

  In addition, the present invention includes a spraying step of spraying a plasticizing liquid, which is a liquid for plasticizing the toner base particles and the resin fine particles, onto the resin fine particle-attached toner base particles with stirring as a subsequent step of the attaching step. It is characterized by that.

  The present invention also provides a capsule toner manufactured by the above-described capsule toner manufacturing method.

  According to the present invention, the capsule toner manufacturing method includes a cooling step, an attaching step, and a film forming step. In the cooling step, the resin fine particles are cooled to a temperature not higher than the embrittlement temperature of the resin fine particles. In the adhering step, the resin cooled in the cooling step in the powder channel in which the toner base particles containing the binder resin and the colorant are flowing in the rotary agitating device including the rotary agitating means and the powder channel. The fine particles are charged while maintaining the temperature below the embrittlement temperature of the resin fine particles, the toner base particles and the resin fine particles are mixed with stirring, and the resin fine particles are adhered to the surface of the toner base particles to thereby form the resin fine particles. Adhering toner base particles are obtained. In the film forming step, stirring is continued until the resin fine particles on the surface of the toner base particles with the resin fine particles are formed, thereby forming a resin coating layer on the surface of the toner base particles.

  In the adhering step, resin fine particles having a temperature not higher than the embrittlement temperature are obtained by introducing resin fine particles in a state where the temperature not higher than the embrittlement temperature is maintained in the powder flow path in which the toner mother particles are flowing. Stirring can be performed in the powder channel. That is, since the temperature is equal to or lower than the embrittlement temperature, resin fine particles that are brittle with respect to impact can be stirred in the powder flow path. Therefore, the resin fine particles that are in an aggregated state when charged into the powder channel can be sufficiently crushed, and the crushed resin fine particles can be adhered to the surface of the toner base particles. Accordingly, the resin fine particles can be prevented from remaining in an aggregated state, and the obtained toner can be prevented from containing agglomerated particles having a relatively large particle diameter made of resin fine particles. Occurrence can be suppressed.

  According to the present invention, since the resin fine particles contain a crystalline resin and an amorphous resin, it is possible to obtain a toner having good low-temperature fixability and blocking resistance.

  According to the invention, in the cooling step, the resin fine particles cooled to a temperature not higher than the embrittlement temperature are transported to the powder flow path by a carrier gas having a temperature not higher than the embrittlement temperature, Therefore, the resin fine particles sufficiently cooled in advance to a temperature below the embrittlement temperature can be stably conveyed to the powder channel while maintaining the temperature below the embrittlement temperature. It can be put into the flow path. Therefore, the resin particles in the aggregated state can be stably and sufficiently crushed in the powder channel.

  According to the invention, in the cooling step, the resin fine particles are cooled to a temperature not higher than the embrittlement temperature by the coolant, so that the resin fine particles can be stably cooled to a temperature not higher than the embrittlement temperature.

  Further, according to the present invention, since liquid nitrogen or its evaporated gas is used as the coolant, the resin fine particles can be stably cooled to a temperature equal to or lower than the embrittlement temperature.

  Further, according to the present invention, as a step subsequent to the adhering step, a spraying step of spraying a plasticizing liquid, which is a liquid for plasticizing the toner base particles and the resin fine particles, onto the resin fine particle-adhered toner base particles is included. By spraying the plasticizing liquid onto the resin fine particle-attached toner base particles, the resin fine particles on the surface of the resin fine particle-attached toner base particles can be softened. It can be formed into a film.

  According to the invention, the toner is produced by the capsule toner production method of the invention. In the capsule toner manufacturing method of the present invention, the resin fine particles can be sufficiently crushed in the powder flow path. Therefore, the toner manufactured by the capsule toner manufacturing method of the present invention has white spots on the fixed image. Generation | occurrence | production can be suppressed.

It is process drawing which shows the manufacturing method of the capsule toner which is one Embodiment 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. Capsule Toner A capsule toner according to an embodiment of the present invention includes a plurality of capsule toner particles. The capsule toner particles include toner base particles and a resin coating layer.

(Toner mother particles)
The toner base particles include a binder resin 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 resin and styrene acrylate copolymer resin can be used. And acrylic resins such as polymethyl methacrylate resin, polyolefin resins such as polyethylene resin, polyester resins, polyurethane resins, 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 individually by 1 type, or can use 2 or more types together.

  Among the binder resins described above, the polyester resin is excellent in transparency, and can impart good powder fluidity, low-temperature fixability, and secondary color reproducibility to the capsule toner particles. Suitable for resin. Known polyester resins 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 individually by 1 type, or can use 2 or more types together.

  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 polyester resin to be produced reach a predetermined value. Thereby, a polyester resin 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 resin can be adjusted by appropriately changing the blending ratio of polybasic acid and polyhydric alcohol, the reaction rate, etc., and thus the properties of the resulting polyester resin Can be denatured. When trimellitic anhydride is used as the polybasic acid, a modified polyester can be obtained by easily introducing a carboxyl group into the main chain of the polyester resin. A self-dispersible polyester resin 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 resin can also be used. A polyester resin and an acrylic resin may be grafted.

The glass transition temperature of the binder resin is preferably 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 capsule toner is thermally aggregated easily occurs inside the image forming apparatus, which may reduce storage stability. When the glass transition temperature of the binder resin exceeds 80 ° C., the fixability of the capsule toner to the recording medium is lowered, and there is a possibility that fixing failure occurs.
The softening temperature of the binder resin is preferably 60 ° C. or higher and 140 ° C. or lower.

  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, risor 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 addition amount of the colorant 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 master batch and the composite particles are mixed in the toner composition during dry mixing described later.

  The toner base particles may contain a charge control agent in addition to the binder resin 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 positive charge control include nigrosine dyes, basic dyes, quaternary ammonium salts, quaternary phosphonium salts, aminopyrines, pyrimidine compounds, polynuclear polyamino compounds, aminosilanes, nigrosine dyes and derivatives thereof, 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. A charge control agent can be used individually by 1 type, or can use 2 or more types together as needed. 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 may contain a release agent in addition to the binder resin and the colorant. 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 release agents, and graft modified products of vinyl monomers and release agents.

The addition amount of the release agent is not particularly limited and can be appropriately selected from a wide range, but is preferably 0.2 parts by weight or more and 20 parts by weight or less, more preferably 0.5 parts by weight or more with respect to 100 parts by weight of the binder resin. It is 10 parts by weight or less, particularly preferably 1.0 part by weight or more and 8.0 parts by weight or less.
The melting point of the release agent is preferably 60 ° C. or higher and 120 ° C. or lower.

  The volume average particle diameter of the toner base particles is preferably 4 μm or more and 8 μm or less. When the volume average particle diameter of the toner base particles 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 to a particle size within this range, a high image density can be obtained even if the amount of capsule toner attached to the recording medium is small, and the toner consumption can be reduced.

  If the volume average particle size of the toner base particles is less than 4 μm, the toner base particles have a too small particle size, which may result in high charge and low fluidity. When the capsule toner is highly charged and fluidized, the capsule toner cannot be stably supplied to the photoconductor, which may cause background fogging and a decrease in image density.

  When the volume average particle diameter of the toner base particles exceeds 8 μm, the particle diameter of the toner base particles is too large, so that the layer thickness of the formed image becomes large, resulting in an image with remarkable graininess, and a high-definition image cannot be obtained. Further, when the volume average particle diameter is increased, the specific surface area of the toner base particles is decreased, and the charge amount of the capsule toner is decreased. When the charge amount of the capsule toner is small, the capsule toner is not stably supplied to the photoconductor, and there is a possibility that internal contamination due to toner scattering may occur.

The coefficient of variation of the toner base particles is preferably 18 or more and 25 or less.
The softening temperature of the toner base particles is preferably 60 ° C. or higher and 140 ° C. or lower, and the glass transition temperature of the toner base particles is preferably 30 ° C. or higher and 80 ° C. or higher.

(Resin coating layer)
The surface of the toner base particles is coated with a resin coating layer.

  The resin coating layer is formed by forming resin fine particles into a film on the surface of toner base particles in a capsule toner manufacturing method described later.

  As the resin constituting the resin fine particles, for example, a resin used for a toner material can be used, and examples thereof include a polyester resin, an acrylic resin, a styrene resin, and a styrene-acrylic copolymer.

  The resin constituting the resin fine particles can be classified into an amorphous resin and a crystalline resin depending on the difference in the arrangement state of the polymers.

  An amorphous resin is a resin in which a polymer is in an amorphous state, has low crystallinity, and has a crystallinity index of less than 0.6 or more than 1.5. The crystalline resin is a resin in which a polymer has a regular molecular structure, the ratio of crystal parts (crystallinity) in the resin is large, and the crystallinity index is 0.6 or more and 1.5 or less.

  The crystallinity index is a value defined by the ratio of the softening temperature of the resin to the highest endothermic peak temperature (softening temperature / highest endothermic peak temperature) and is an index of crystallinity. The highest endothermic peak temperature refers to the temperature of the peak on the highest temperature side among the observed endothermic peaks. If the maximum endothermic peak temperature is within 20 ° C. of the softening temperature, it is regarded as the melting point, and if the difference from the softening temperature exceeds 20 ° C., it is considered to be due to glass transition.

  The degree of crystallization can be adjusted by the types and ratios of the raw material monomers of the resin constituting the resin fine particles, and the production conditions such as reaction temperature, reaction time, and cooling rate.

<Crystalline resin>
Examples of the crystalline resin include a crystalline polyester resin, a crystalline polyethylene resin, and a crystalline polypropylene resin.

  The crystalline polyester resin is obtained by polycondensing an alcohol component containing 60 mol% or more of an aliphatic diol having 3 to 10 carbon atoms and a carboxylic acid component containing 80 mol% or more of an aromatic dicarboxylic acid compound. Preferably, it is obtained by polycondensation of an alcohol component containing 80 mol% or more of an aliphatic diol having 4 to 10 carbon atoms and a carboxylic acid component containing 80 mol% or more of an aromatic dicarboxylic acid compound. desirable. The content of the aliphatic diol having 3 to 10 carbon atoms in the alcohol component is more preferably 85 mol% or more from the viewpoint of promoting crystallinity. The content of the aromatic carboxylic acid in the carboxylic acid component is more preferably 85 mol% or more from the viewpoint of low-temperature fixability, durability, and charging stability under high-temperature and high-humidity conditions.

  As the aliphatic diol having 3 to 10 carbon atoms, a linear aliphatic diol having 4 to 10 carbon atoms and a branched aliphatic diol having 3 to 10 carbon atoms are preferable. A crystalline polyester resin obtained by using, as a raw material monomer, an alcohol component containing a linear aliphatic diol as a main component and an alcohol component containing a branched aliphatic diol and an aromatic carboxylic acid compound is combined. By containing as a resin, the low-temperature fixability can be further improved. The branched aliphatic diol refers to a diol having a branched alkylene group to which two OH groups are bonded or a diol having a secondary OH group.

  Examples of the linear aliphatic diol having 4 to 10 carbon atoms include 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,4-butenediol and the like are preferable, and α, ω-linear alkanediol is preferable from the viewpoint of promoting crystallinity, and 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, and 1,10-decanediol are more preferred.

  The content of the linear aliphatic diol having 4 to 10 carbon atoms is preferably 50 to 90 mol% in the alcohol component, and more preferably 60 to 90 mol% from the viewpoint of promoting crystallinity.

  Examples of the branched aliphatic diol having 3 to 10 carbon atoms include 1,2-propanediol, 1,3-butanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, and the like. It is done.

  The content of the branched aliphatic diol having 3 to 10 carbon atoms is preferably 10 to 50 mol% in the alcohol component, and more preferably 10 to 40 mol% from the viewpoint of promoting low-temperature fixability.

  Molar ratio of linear aliphatic diol having 4 to 10 carbon atoms and branched aliphatic diol having 3 to 10 carbon atoms (linear aliphatic diol having 4 to 10 carbon atoms / branched chain having 3 to 10 carbon atoms) Type aliphatic diol) is preferably 60/40 to 90/10, more preferably 70/30 to 85/15, and still more preferably 70/30 to 80/20, from the viewpoint of low-temperature fixability.

  The alcohol component may contain an alcohol other than the aliphatic diol having 3 to 10 carbon atoms as long as the effects of the present invention are not impaired. Examples of the alcohol component include aliphatic diols having 3 to 10 carbon atoms such as ethylene glycol; polyoxypropylene (22) -2, 2-bis-4-hydroxyphenylpropane, polyoxyethylene 22-2,2-bis. Aromatic diols such as alkylene oxide adducts of bisphenol A typified by 4-hydroxyphenylpropane; alicyclic diols such as 1,4-cyclohexanedimethanol; polyhydric alcohols having a valence of 3 or more such as glycerin and pentaerythritol Is mentioned.

  As the aromatic dicarboxylic acid compound, compounds having a benzene skeleton such as phthalic acid, isophthalic acid, terephthalic acid and their anhydrides, alkyl carbon number 1 to 3 esters and the like are preferable. From the viewpoint of promotion, terephthalic acid and its derivatives are more preferable.

As carboxylic acid components other than the aromatic dicarboxylic acid compound, oxalic acid, malonic acid,
Aliphatic dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid; fats such as cyclohexanedicarboxylic acid Cyclic dicarboxylic acids; trivalent or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid; and derivatives of these acids such as anhydrides and alkyl carbon number 1-3 esters. Among these, fumaric acid is preferable from the viewpoint of promoting crystallinity.

<Amorphous resin>
Examples of the amorphous resin include amorphous styrene resin such as amorphous polystyrene resin, amorphous styrene acrylic copolymer resin, amorphous acrylic resin such as amorphous polymethyl methacrylate resin, and amorphous resin. Examples thereof include amorphous polyolefin resins such as crystalline polyethylene resins, amorphous polyester resins, amorphous polyurethane resins, and amorphous epoxy resins.

  The amorphous polyester resin contains an alcohol component containing 60 mol% or more of an aliphatic diol having 3 to 10 carbon atoms and 80 mol% or more of an aromatic dicarboxylic acid compound, and has 12 carbon atoms as an aromatic dicarboxylic acid compound. It is obtained by polycondensation with a carboxylic acid component containing 1 to 50 mol% of the above polycyclic aromatic dicarboxylic acid compound, and preferably contains 80 mol% or more of an aliphatic diol having 4 to 10 carbon atoms. And an carboxylic acid component containing 80 mol% or more of an aromatic dicarboxylic acid compound and 1 to 50 mol% of a polycyclic aromatic dicarboxylic acid compound having 12 or more carbon atoms as the aromatic dicarboxylic acid compound; Those obtained by polycondensation of are desirable.

  About the alcohol component, the thing similar to the aspect of crystalline polyester resin is mentioned.

The carboxylic acid component is the same as that of the crystalline polyester resin in that it contains a specific amount or more of an aromatic dicarboxylic acid compound, but a specific amount of a polycyclic aromatic dicarboxylic acid having 12 or more carbon atoms. A characteristic feature of the amorphous polyester resin is that the acid compound is contained in the carboxylic acid component.

  Examples of the polycyclic aromatic dicarboxylic acid compound having 12 or more carbon atoms include 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 4, Compounds having a benzene skeleton such as 4-biphenyldicarboxylic acid and derivatives thereof such as acid anhydrides and alkyl carbon number 1 to 3 esters are preferable, and the number of carbon atoms is preferably 12 to 30, and more preferably 12 to 24. Among these, 2,6-naphthalenedicarboxylic acid and 1,5-naphthalenedicarboxylic acid are preferable from the viewpoint of crystallinity of the polyester resin.

  The content of the polycyclic aromatic dicarboxylic acid compound having 12 or more carbon atoms is 1 to 50 mol% in the carboxylic acid component, and 5 to 40 mol from the viewpoint of the crystallinity of the polyester resin and the low-temperature fixability of the toner. % Is preferable, and 10 to 30 mol% is more preferable.

  Furthermore, the total content of the polycyclic aromatic dicarboxylic acid compound and the aromatic dicarboxylic acid compound exemplified in the embodiment of the crystalline polyester resin is 80 mol% or more in the carboxylic acid component, and the low temperature fixability and durability From the viewpoint of the chargeability and charging stability under high temperature and high humidity conditions, 85 mol% or more is preferable, and 90 to 100 mol% is more preferable.

  Examples of the carboxylic acid component other than the aromatic dicarboxylic acid compound are the same as those of the crystalline polyester resin.

  In both the crystalline polyester resin embodiment and the amorphous polyester resin embodiment, the molar ratio of the alcohol component to the carboxylic acid component (alcohol component / carboxylic acid component) is determined from the viewpoint of fixing to paper and charging stability. 100 / 70-100 / 120 are preferable.

  Polyester resin is also excellent as a binder for colorants such as pigments because of its high refractive index and excellent optical properties, and since it has a high degree of freedom in thermal design and can control melting properties at lower temperatures, In particular, it exhibits excellent functionality when used in low-temperature fixing toners.

  When preparing the crystalline polyester resin, the condensation polymerization of the alcohol component and the carboxylic acid component is performed, for example, in an inert gas atmosphere at a temperature of 120 to 230 ° C. using an esterification catalyst if necessary. Can do.

  The amorphous styrene acrylic copolymer resin can be obtained, for example, by copolymerizing a styrene monomer, an acrylic monomer, and an acrylic resin monomer. A publicly known thing can be used as an acrylic monomer, For example, acrylic acid which has a substituent, methacrylic acid which has a substituent, acrylic acid ester which has a substituent, methacrylic acid ester which has a substituent, etc. are mentioned.

  Examples of the acrylic resin monomer include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-acrylic acid 2- Acrylic acid ester monomers such as ethylhexyl, acrylate n-octyl, decyl acrylate, dodecyl acrylate, methyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, methacryl Methacrylic acid ester monomers such as acid n-hexyl, 2-ethylhexyl methacrylate, n-octyl methacrylate, decyl methacrylate, dodecyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate And the like hydroxyl group (hydroxyl group) containing (meth) acrylic acid ester monomers such as. Acrylic resin monomers can be used alone or in combination of two or more.

  A well-known thing can be used as a styrene-type monomer, For example, styrene, (alpha) -methylstyrene etc. are mentioned, 1 type can be used individually or 2 or more types can be used together. The polymerization is carried out by solution polymerization, suspension polymerization, emulsion polymerization or the like using a general radical initiator.

  The amorphous styrene-acrylic copolymer resin can control the hydrophobicity by blending of monomers, and can suppress a decrease in charge in a high-temperature and high-humidity environment. Further, since the degree of polymerization and the blending ratio can be selected, the degree of freedom in thermal design is high and the toner material can be suitably used.

The glass transition temperature of the resin constituting the resin fine particles is preferably higher than the glass transition temperature of the binder resin contained in the toner base particles, and more preferably 50 ° C. or more and 100 ° C. or less.
The softening temperature of the resin constituting the resin fine particles is preferably 60 ° C. or higher and 160 ° C. or lower.

  As described above, the capsule toner of the present invention is excellent in durability and storage stability because the resin coating layer is formed on the surface of the toner base particles and the encapsulated components are protected. When such a capsule toner is used for image formation, it is possible to obtain a high-definition and good-quality image without uneven density.

The capsule toner of the present invention has a low content of aggregated particles, which are particles in which resin fine particles are aggregated. Aggregated particles are relatively large particles having a particle size of 12 μm or more. The content of aggregated particles in the capsule toner of the present invention is 4% or less. Therefore, it is possible to suppress the generation of white spots in the fixed image due to the agglomerated particles having a relatively large particle diameter, and to improve the image quality of the formed image.
The method for producing the toner of the present invention will be described below.

2. Capsule Toner Manufacturing Method FIG. 1 is a process diagram showing a capsule toner manufacturing method according to an embodiment of the present invention. The capsule toner manufacturing method of this embodiment 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 the resin fine particles are cooled to a temperature equal to or lower than the embrittlement temperature. It includes a cooling step S3 and a coating step S4 for forming a resin coating layer on the surface of the toner base particles.

(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 method for producing the toner base particles is not particularly limited, and can be performed by a known method. For example, a dry method such as a pulverization method, a suspension polymerization method, an emulsion aggregation method, a dispersion polymerization method, a dissolution suspension method, Examples include wet methods such as melt emulsification. Hereinafter, a method for producing toner base particles by a pulverization method will be described.

(Production method of 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 apparatus, ongmill (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.

  As the kneading machine, a known kneading machine can be used. For example, a general kneading machine such as a twin-screw extruder, a triple roll, a lab 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.

(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 to coat the toner base particles in the subsequent coating step S4. By coating the toner base particles, aggregation of the capsule toner during storage due to melting of a low melting point component such as a release agent contained in the toner base particles can be prevented.

  The resin fine particles are obtained, for example, by emulsifying and dispersing the resin constituting the resin fine particles described above with a homogenizer or the like. Further, it can be obtained by polymerization of monomer components of the resin constituting the resin fine particles.

  Hereinafter, resin fine particles prepared using an amorphous resin are also referred to as amorphous resin fine particles, and resin fine particles prepared using a crystalline resin are also referred to as crystalline resin fine particles.

  The volume median particle diameter of the resin fine particles needs to be sufficiently smaller than the volume 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 median particle size 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. Therefore, the capsule toner manufactured by the method of the present invention is easily caught by the cleaning blade at the time of cleaning, and the cleaning property is improved.

(3) Cooling step S3
In the cooling step S3, the resin fine particles are cooled to a temperature not higher than the embrittlement temperature of the resin fine particles. The embrittlement temperature of the resin fine particles is a temperature serving as a scale indicating the low temperature strength characteristics of the resin fine particles. The resin fine particles are preferably cooled to a temperature 2 ° C. or more and 20 ° C. or less lower than the embrittlement temperature.

  Examples of the method for cooling the resin fine particles include a method for directly cooling the resin fine particles, and a method for indirectly cooling the resin fine particles with a carrier gas that conveys the resin fine particles to a powder passage to be described later.

  As a method of directly cooling the resin fine particles, a method of cooling the resin fine particles by convection, radiation, heat transfer, or the like in a temperature-controlled space can be mentioned.

  As an apparatus capable of cooling the resin fine particles by such a method, a temperature-controllable refrigerator is raised. Specifically, resin fine particles are cooled by a freezer of a type that circulates cold air at a constant temperature, a cooler that adjusts the temperature of the resin fine particles by radiation while keeping the wall surface temperature low in a vacuum, and a temperature control device such as a Peltier element. And the like. By placing the resin fine particles in an apparatus having such a cooling capacity for a sufficient time, the temperature of the resin fine particles can be cooled to a temperature equal to or lower than the embrittlement temperature.

  In indirect cooling with a carrier gas, a coolant is used to cool the resin fine particles. Examples of the coolant include liquid nitrogen and its evaporated gas. In the method of directly cooling the resin fine particles, the effective temperature of the resin fine particles can be accurately known.

  Examples of the carrier gas that transports the resin fine particles to the powder flow path and indirectly cools include cooled compressed air and liquid nitrogen vapor. The cooling temperature of the carrier gas during the transportation of the resin fine particles to the powder channel is preferably −60 ° C. or more and 0 ° C. or less. By transporting the resin fine particles with a carrier gas having a temperature in this temperature range, the resin fine particles can be cooled to below the embrittlement temperature.

  By cooling the resin fine particles to a temperature equal to or lower than the embrittlement temperature by the method as described above, the resin fine particles having a temperature equal to or lower than the embrittlement temperature of the resin fine particles are charged into the powder channel in the subsequent coating step S4. be able to.

  Furthermore, when the resin fine particles cooled to a temperature not higher than the embrittlement temperature are conveyed to the powder flow path by a carrier gas having a temperature not higher than the embrittlement temperature of the resin fine particles, the resin fine particles are caused to become brittle in the subsequent coating step S4. The powder can be stably fed into the powder channel while maintaining the temperature below the crystallization temperature.

(4) Covering step S4
The coating step S4 includes a temperature adjustment step S4a, an adhesion step S4b, a spraying step S4c, a film forming step S4d, and a recovery step S4e. These steps are performed using the following toner production apparatus.

<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. 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.

(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 rotation axis 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 this powder flow path 202, toner base particles, resin fine particles and gas flow. The powder flow path 202 is provided so that the powder flow direction in which the toner base particles and the resin fine particles flow is constant.

(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 rotary shaft member 218 has an axis line that coincides with the axis line of the stirring unit 208 and is formed on the surface 208c on one axial direction side of the stirring unit 208 so as to penetrate the side wall including the surface 208c in the thickness direction. It is a cylindrical rod-shaped member which is provided so as to be inserted through the shaft and rotates 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. The rotary shaft portion 221a is provided with a gas discharge portion 222 to which a gas discharge port 221b is connected.

(Spraying means)
The spraying means 203 is provided so as to be inserted into an opening formed in the outer wall of the powder flow path 202, and is closest to an opening 211 in the flow direction of the resin fine particle-attached toner base particles described later in the powder flow portion 209. It is provided in the powder flow part on the side. The spraying unit 203 mixes a liquid storage unit that stores a plasticizing liquid that is a liquid that plasticizes toner base particles and resin fine particles, a carrier gas supply unit that supplies a carrier gas, and a plasticizing liquid and a carrier gas. A two-fluid nozzle that sprays the resulting mixture toward the resin fine particle-attached toner base particles present in the powder flow path 202 and sprays the droplets of the plasticized liquid onto the resin fine particle-attached toner base particles. Compressed air or the like can be used as the carrier gas. The plasticized liquid fed to the spraying means 203 at a constant flow rate by the liquid feed pump and sprayed by the spraying means 203 is gasified, and the gasified liquid spreads on the surface of the toner base particles with the resin fine particles. As a result, the toner base particles and the 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 adjustment step S4a, the temperature inside the powder flow channel and outside the rotary stirring means can be controlled to a temperature at which the toner base particles and the resin fine particles are not softened and deformed. Further, in the spraying step S4c and the film forming step S4d, variations in temperature applied to the resin fine particle-attached toner base particles and the plasticizing liquid can be reduced, and a stable fluid state of the resin fine particle-attached toner base particles can be maintained. As the temperature adjustment jacket, for example, a jacket whose inner diameter is larger than the outer diameter of the powder flow path tube is used.

  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-adhered toner base particles usually collide with the inner wall of the powder flow path many times, but at the time of the collision, a part of the collision energy is converted into thermal energy and accumulated in the resin fine particle-adhered toner base particles. As the number of collisions increases, the thermal energy accumulated in the resin fine particle-attached toner base particles increases, and the resin fine particle-attached toner base particles soften 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 resin fine particle-attached toner mother particles to the inner wall of the powder flow path is reduced, and the inner wall of the powder flow path 202 due to a rapid rise in the apparatus internal temperature. Therefore, it is possible to reliably prevent the adhesion of the resin fine particle-attached toner base particles to the resin fine particles, and to prevent the inside of the powder channel 202 from being narrowed by the resin fine particle-attached toner base particles. Therefore, the capsule toner can be manufactured with a high yield.

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

(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 (inputs) toner base particles and resin fine particles, a supply pipe 212 that connects the hopper and the powder flow path 202, and an electromagnetic valve 213 that is provided in the supply pipe 212. Is provided. The toner base particles and resin fine 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. The toner base particles and resin fine particles supplied to the powder flow path 202 flow in a constant powder flow direction by stirring by the rotary stirring means 204. Further, when the flow path in the supply pipe 212 is closed by the electromagnetic valve 213, the toner base particles and the resin fine 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 capsule toner particles flowing through the powder flow path 202 are collected in the collection tank 215 through the collection pipe 216. In addition, when the flow path in the collection pipe 216 is closed by the electromagnetic valve 217, the capsule toner flowing through the powder flow path 202 is not collected.

  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 part 209 and the agitation part 208, it is possible to more reliably prevent adhesion of the resin fine particle-adhered toner base particles to the inner wall of the powder flow path 202. .

  The toner manufacturing apparatus 201 as described above can also be obtained by combining a commercially available stirring apparatus and a spraying apparatus. As a commercially available stirring apparatus provided with a powder flow path and a rotary stirring apparatus, for example, a hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.) and the like can be mentioned. By attaching a spraying device for spraying the plasticizing liquid to such a stirring device, the toner manufacturing device 201 used in the capsule toner manufacturing method of the present embodiment can be obtained.

(Temperature adjustment step S4a)
In the temperature adjustment step S4a, 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. Thereby, the temperature in the powder flow path 202 can be controlled to a temperature at which the toner base particles, the resin fine particles, and the resin fine particle-adhered toner base particles are not softened and deformed.

  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 powder flow path 202 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 in the powder flow path 202 is lower than 30 ° C., the drying rate of the plasticizing liquid is slowed and productivity is lowered. Therefore, in order to prevent aggregation of the toner base particles, it is necessary to maintain the temperature of the powder flow path 202 and the rotary stirring means 204 below the glass transition temperature of the toner base particles.

(Adhesion process S4b)
In the attaching step S4b, resin fine particles are adhered to the surface of the toner base particles to obtain resin fine particle-attached toner base particles.

  In the adhering step S4b, first, toner base particles are introduced from the powder introduction unit 206 in a state where the rotating shaft member 218 of the rotary stirring unit 204 is rotating. Thereafter, the fine resin particles cooled in the above-described cooling step S3 are put into the powder flow path 202 where the toner base particles are flowing in the direction of the arrow 214 while maintaining the temperature below the embrittlement temperature. .

  In the adhering step S4b, resin fine particles having a temperature not higher than the embrittlement temperature are introduced into the powder flow path 202 in which the toner mother particles are flowing while maintaining the temperature not higher than the embrittlement temperature. Agitation can be performed in the powder flow path 202. That is, since the temperature is equal to or lower than the embrittlement temperature, the resin fine particles that are brittle against impact can be stirred in the powder flow path 202. Therefore, the resin fine particles that are in an aggregated state when charged into the powder channel 202 can be sufficiently crushed to a submicron level that is about 1 to 10 times the primary particle size of the resin fine particles. Then, the pulverized resin fine particles are adhered to the surface of the toner base particles, whereby the resin fine particle-attached toner base particles can be obtained. Therefore, it is possible to suppress the resin fine particles from remaining in an aggregated state, and it is possible to suppress the inclusion of aggregated particles made of resin fine particles having a relatively large particle size in the obtained capsule toner. Can be prevented from occurring. Note that the more resin particles contain a crystalline resin, the more resin particles before being introduced into the powder flow path 202 tend to aggregate, but even in this case, the resin particles can be sufficiently crushed.

  The amount of the resin fine particles added is preferably 3 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the toner base particles. If the amount of the resin fine particles added is less than 3 parts by weight, it is difficult to uniformly coat the toner base particles with the resin fine particles, and depending on the type of the toner base particles, the storage stability may be deteriorated. When the addition amount of the resin fine particles exceeds 20 parts by weight, some resin fine particles do not adhere to the toner base particles and are contained in the capsule toner in a free state.

  In the attaching step S4b, the peripheral speed of the outermost periphery of the rotary stirring means 204 is preferably set to 50 m / sec or more and 120 m / sec or less. 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 during rotation to 50 m / sec or more, the toner base particles and the resin fine particles can be isolatedly flowed. When the peripheral speed at the outermost periphery of the rotary stirring means 204 is less than 50 m / sec, the toner base particles and the resin fine particles cannot be isolatedly flowed, so that the toner base particles cannot be uniformly coated with the resin coating layer.

  By setting the peripheral speed at the outermost periphery of the rotating stirring means 204 during rotation to 120 m / sec or less, it is possible to obtain a capsule toner with good cleaning properties. When the peripheral speed at the outermost periphery of the rotary stirring means 204 exceeds 120 m / sec, the toner base particles are spheroidized more than necessary by the mechanical impact force and the thermal energy generated by the mechanical impact force. Toner cleaning performance is reduced.

The toner base particles and resin fine particles preferably collide with the rotating disk 219 perpendicular to the rotating disk 219. Accordingly, the toner base particles and the resin fine particles are sufficiently stirred, and the toner base particles can be more uniformly coated with the resin fine particles, so that the yield of the capsule toner having the uniform resin coating layer can be improved.
The time for the attaching step S4b is preferably 1 minute or more and 20 minutes or less.

(Spraying step S4c)
In the spraying step S4c, a plasticizing liquid that has an effect of plasticizing the resin fine particle-attached toner base particles in a fluidized state without dissolving them is sprayed from the spraying means 203 by the carrier gas. The carrier gas used in this step does not need to be cooled like the carrier gas used in the cooling step S3 described above.

  The sprayed plasticizing liquid is gasified so that the inside of the powder passage 202 has a constant gas concentration, and the gasified plasticizing liquid is discharged out of the powder passage through the through hole 221. Is preferred. As a result, the concentration of the gasified plasticized liquid in the powder channel 202 can be kept constant, and the drying speed of the plasticized liquid can be increased as compared with the case where the concentration is not kept constant. Therefore, the resin fine particle-attached toner mother particles in which the undried plasticized liquid remains are prevented from adhering to other resin fine particle-adhered toner mother particles, and the aggregation of the resin fine particle-adhered toner mother particles is suppressed, and a uniform resin coating layer is obtained. It is possible to further improve the yield of the capsule toner in which is formed.

  The concentration of the gasified plasticized liquid measured by the concentration sensor in the gas discharge unit 222 is preferably about 3% or less. Further, the concentration of the gasified plasticized liquid is more preferably 0.1% or more and 3.0% or less. As a result, aggregation of resin fine particle-attached toner base 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-attached toner base particles is stabilized in the powder flow path 202. As a result, the plasticizing liquid can be sprayed uniformly on the resin fine particle-adhered toner base particles, and the yield of the capsule toner having a uniform resin coating layer can be improved.

  Although it does not specifically limit as a plasticizing liquid, Since it needs to be removed from the resin fine particle adhesion toner base particle after spraying, it is preferable that it is a liquid which is easy to evaporate. Examples of such a liquid include a liquid containing a lower alcohol. Examples of the lower alcohol include methanol, ethanol, propanol and the like. When the plasticizing liquid contains such a lower alcohol, the wettability of the resin fine particles with respect to the toner base particles can be improved, and the resin fine particles adhere to the entire surface or most of the toner mother particles, and are further deformed and formed into a film. It becomes easy. Further, since the lower alcohol has a high vapor pressure, the drying time when removing the plasticizing liquid can be further shortened, and aggregation of the toner fine particle-adhering toner base particles can be suppressed.

  The viscosity of the plasticizing liquid is preferably 5 cP or less. The viscosity of the plasticizing liquid is measured at 25 ° C., and can be measured by, for example, a cone plate type rotary viscometer. When the viscosity is 5 cP or less, it is possible to spray the plasticized liquid having a fine droplet diameter without increasing the spray droplet diameter of the plasticized liquid sprayed from the spraying means 203. Accordingly, the surface of the resin fine particle-attached toner base particles can be uniformly wetted and blended, and the resin fine particle-attached toner base particles can be softened by a synergistic effect with the collision energy. As a result, a capsule toner having a uniform resin coating layer can be obtained.

  The angle θ formed between the liquid spray direction which is the axial direction of the two-fluid nozzle of the spray means 203 and the powder flow direction which is the flow direction of the resin fine particle-attached toner mother particles in the powder flow path 202 is 0 ° or more and 45 °. The following is preferable. When θ is in such a range, the plasticized liquid droplet is prevented from recoiling on the inner wall of the powder flow path 202, and the yield of the capsule toner can be further improved. When the angle θ exceeds 45 °, the plasticized liquid droplets recoil on the inner wall of the powder flow path 202, and the plasticized liquid tends to stay, and the aggregation of the resin fine particle-attached toner base particles occurs and the capsule toner The yield of is deteriorated.

  The spreading angle φ of the plasticizing 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 plasticizing liquid onto the resin fine particle-attached toner base particles.

  The spraying speed of the plasticizing liquid is preferably 0.2 g / min or more and 3 g / min or less, and the air flow rate is preferably 5 l (liter) / min or more and 30 l (liter) / min or less.

(Film forming step S4d)
In the film forming step S4d, the rotation of the rotary stirring means 204 is continued until the resin fine particles on the surface of the resin fine particle-attached toner mother particles are softened to form a film, thereby forming a resin coating layer on the toner mother particle surfaces.

  The film forming step S4d starts simultaneously with the spraying step S4c and ends simultaneously. In this case, the time for the film forming step S4d is preferably 2 minutes or more and 40 minutes or less.

  In addition, the film forming step S4d may be started simultaneously with the spraying step S4c and may be ended after the spraying step S4c. In this case, the time for the film forming step S4d is preferably 3 minutes or more and 60 minutes or less.

  In the film forming step S4d, the resin fine particle-attached toner base particles are stirred and mixed for the time in the above range, whereby the resin fine particles can be appropriately formed on the surface of the toner base particles.

  In the spraying step S4c and the film forming step S4d, 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. 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-attached toner mother particles can be isolatedly flowed. When the peripheral speed at the outermost periphery is less than 30 m / sec, the resin fine particle-attached toner base particles cannot be isolatedly flowed, and there is a possibility that a uniform resin coating layer cannot be formed.

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

(Recovery step S4e)
In the collecting step S4e, the plasticizing liquid spray from the spraying means and the rotation of the rotating stirring means 204 are stopped, and the capsule toner is discharged out of the apparatus from the powder collecting unit 207 and collected.

(Mixing process)
In the capsule toner manufacturing method of the present invention, amorphous resin particles and crystalline resin particles may be used as the resin particles. By using amorphous resin particles and crystalline resin particles as the resin particles, a capsule toner having excellent low-temperature fixability and blocking resistance can be obtained.

  When amorphous resin particles and crystalline resin particles are used as the resin particles, the amorphous resin particles and the crystalline polyester resin particles prepared in the resin particle preparation step S2 are mixed with a mixer such as a Henschel mixer. Mixed resin fine particles are obtained. Hereinafter, this step is referred to as a mixed resin fine particle preparation step. The mixed resin fine particle preparation step is performed after the resin fine particle preparation step S2 and before the cooling step S3. In the steps after the cooling step S3, the mixed resin fine particles are used as the resin fine particles.

  Known mixers 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.

  When the content of the crystalline resin fine particles in the mixed resin fine particles is small, the effect of melting the resin coating layer at the time of fixing is not sufficient, and the low-temperature fixability is lowered. When the content of the crystalline resin fine particles in the mixed resin fine particles is large, it becomes difficult to effectively utilize the heat resistance effect of the amorphous resin for blocking improvement. By setting the content of the crystalline resin fine particles in the mixed resin fine particles to 20% by weight or more and 50% by weight or less, the effects of low-temperature fixability and blocking resistance can be maximized. In addition, when the crystalline resin is uniformly present between the amorphous resins in the resin coating layer, the above effect functions stably and effectively.

  The volume median particle size of the crystalline resin fine particles is preferably smaller than the volume median particle size of the amorphous resin fine particles. For example, the volume median particle size of the crystalline resin fine particles is preferably 50% or more and less than 100% with respect to the volume median particle size of the amorphous resin fine particles. When the volume median particle size of the crystalline resin fine particles is less than 50% of the volume median particle size of the amorphous resin fine particles, it is difficult to handle the crystalline resin fine particles, and thus the toner base particles cannot be suitably coated. . When the volume median particle size of the crystalline resin fine particles is 100% or more with respect to the volume median particle size of the amorphous resin fine particles, there arises a problem that the blocking resistance of the capsule toner is impaired by the crystalline resin.

  The toner base particles having the resin coating layer formed on the surface thus obtained may be used as a capsule toner as they are, or those added with an external additive may be used as a capsule toner.

  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 addition amount of the external additive is preferably 1 to 10 parts by weight with respect to 100 parts by weight of the capsule toner.

3. Developer The capsule toner of the present invention can be used as a one-component developer or a two-component developer. When used as a one-component developer, the capsule toner is used alone without using a carrier. When used as a two-component developer, the capsule toner of the present invention is used together with a carrier.

  As the carrier, a known carrier can be used. For example, a resin-coated carrier or a resin in which iron or copper, zinc, nickel, cobalt, manganese, chromium or the like alone or a composite ferrite and carrier core particles are coated with a coating material. And a resin-dispersed carrier in which magnetic particles are dispersed.

  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 kind can be used alone, or two or more kinds 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 volume resistivity of the carrier is preferably 10 ⁸ Ω · cm or more, and 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 capsule toner and the carrier in the two-component developer is not particularly limited, and can be appropriately selected according to the kind of the capsule toner and the carrier. For example, when mixed with a resin-coated carrier (density 5 to 8 g / cm ² ), the capsule 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. The coverage of the carrier with the capsule toner is preferably 40 to 80%.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.
[Softening temperature of resin and toner base particles]
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).

[Glass transition temperature of resin and toner base particles]
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 was heated at a heating rate of 10 ° C. per minute and a DSC curve was measured. did. In the obtained DSC curve, an endothermic peak was measured.

  Among the observed endothermic peaks, the highest peak temperature, which is the temperature of the peak at the highest temperature side, is the melting point if the difference is within 20 ° C. from the softening temperature, and the glass transition if the difference from the softening temperature exceeds 20 ° C. Shall be attributed to The intersection of the straight line obtained by extending the base line on the high temperature side from the endothermic peak corresponding to the glass transition to the low temperature side and the tangent line drawn at the point where the gradient is maximum with respect to the curve from the rising part of the peak to the vertex. The temperature was the glass transition temperature (Tg).

  If the sample contains an amorphous resin in addition to the crystalline polyester resin, or if the crystalline polyester resin contains an amorphous part, the peak temperature observed at a temperature lower than the maximum endothermic peak temperature, or endothermic The glass transition temperature was defined as the temperature at the intersection of the base line extension below the maximum peak temperature and the tangent line indicating the maximum slope from the peak rising portion to the peak apex.

  When the binder resin contains an amorphous resin in addition to the crystalline polyester resin, or when the crystalline polyester resin contains an amorphous part, a peak temperature observed at a temperature lower than the highest endothermic peak temperature, or The glass transition temperature was defined as the temperature at the intersection of the baseline extension line below the maximum peak temperature of endotherm and the tangent line showing the maximum slope from the peak rising portion to the peak apex.

[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. From these, the standard deviation in volume average particle size and volume particle size distribution was determined. The coefficient of variation (CV value,%) was calculated based on the following formula (1).
CV value (%) = (standard deviation in volume particle size distribution / volume average particle diameter) × 100 (1)

[Maximum peak temperature of resin endotherm]
The temperature (Tc) corresponding to the highest endothermic peak temperature was measured in the same manner as the glass transition temperature measurement method.

[Resin crystallinity index]
The temperature (Tc) corresponding to the highest endothermic peak temperature was measured in the same manner as the glass transition temperature measurement method. The crystallinity index was calculated from the following formula 2 using the softening temperature (Tm) measured by the above-described softening temperature measurement method and the temperature (Tc) corresponding to the highest endothermic peak temperature.
Crystallinity index = Tm / Tc (2)

[Volume median particle size of resin fine particles and mixed resin fine particles]
Measurement was performed using a laser diffraction / scattering particle size distribution measuring apparatus (trade name: Microtrack MT3000, manufactured by Nikkiso Co., Ltd.). In order to prevent agglomeration of the measurement sample (resin fine particles or mixed resin fine particles), a dispersion in which the measurement sample is dispersed in an aqueous solution of Family Fresh (manufactured by Kao Corporation) is charged and stirred, and then injected into the apparatus to perform measurement twice. Perform and find the average. The measurement conditions were: measurement time: 30 seconds, particle refractive index: 1.4, particle shape: non-spherical, solvent: water, solvent refractive index: 1.33. The volume particle size distribution of the measurement sample was measured, and the particle size at which the cumulative volume from the small particle size side in the cumulative volume distribution was 50% was calculated as the volume median particle size D50 (μm) of the particles.

[Brittle temperature of fine resin particles]
The embrittlement temperature of resin fine particles is the temperature at which 50% of the total number of test pieces made of resin constituting the resin fine particles breaks (50% embrittlement temperature) when tested by the following method. ) Temperature measured according to K7216.

The embrittlement temperature of the resin fine particles is obtained by calculation using the following formula (3). In the temperature range of 30 to -50 ° C., the temperature was changed every 5 ° C., 10 test pieces were cooled at each temperature, a destructive test was performed, and the number of test pieces destroyed in the destructive test was obtained. . The specimen gripping tool used was a B type. The test piece used what was directly produced by compression molding so that it might become a rectangular parallelepiped of length 20mm * width 6mm * thickness 2mm. In producing the test piece, the test piece was heated at least above the softening temperature of the resin so that no voids were formed in the test piece. In addition, you may produce a test piece by processing to a predetermined shape by punching or cutting, after producing the thickness of resin into a sheet form. The test piece was cooled in a heat transfer medium charged with dry ice.
Tb = Th + ΔT (S / 100−1 / 2) (3)
Tb: Embrittlement temperature Th: Maximum temperature at which all specimens break ΔT: Measurement temperature interval S: Sum of percentages of fracture at each temperature from the lowest temperature at which all specimens do not break up to Th

  The embrittlement temperature in the mixed resin fine particles is the embrittlement temperature of the resin fine particles having the lowest embrittlement temperature among the plurality of resin fine particles.

[Content of aggregated particles (%)]
The volume particle size distribution of the toner mother particles and the volume particle size distribution of the capsule toner were determined by the same method as the method for measuring the volume average particle diameter of the toner mother particles. Using the volume particle size distribution of the toner base particles, the content Co (%) of toner base particles having a volume average particle diameter of 12 μm or more was determined. Further, the content Ca (%) of the capsule toner having a volume average particle diameter of 12 μm or more was determined using the volume particle size distribution of the capsule toner. Using the following formula (4), the content (%) of aggregated particles in the capsule toner was determined.
Aggregated particle content (%) = Ca (%)-Co (%) (4)

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

  After the above raw materials were premixed for 3 minutes with a Henschel mixer, using a twin screw extruder (trade name: PCM-30, manufactured by Ikegai Co., Ltd.), a cylinder set temperature of 110 ° C. and a barrel rotation speed of 300 revolutions per minute ( 300 rpm) and melt kneading at a raw material supply rate of 20 kg / hour. The melt-kneaded product was cooled with a cooling belt and then coarsely pulverized with a speed mill having a screen of φ2 mm. Thereafter, the toner is finely pulverized by a jet type pulverizer (trade name: IDS-2, manufactured by Nippon Pneumatic Industrial Co., Ltd.) and further classified by an elbow jet classifier (trade name, manufactured by Nittetsu Mining Co., Ltd.). Base particles (volume average particle diameter: 6.9 μm, coefficient of variation: 22, softening temperature: 116 ° C., glass transition temperature: 55 ° C.) were obtained.

[Resin fine particle preparation process]
<Preparation of amorphous resin fine particles A>
By reacting polyoxypropylene (2,3) -2,2-bis (4-hydroxyphenyl) propane, ethylene glycol, terephthalic acid, isophthalic acid, and trimellitic anhydride, amorphous polyester resin 1 (softening temperature) : 140 ° C., endothermic peak temperature: 69 ° C., glass transition temperature: 67 ° C., crystallinity index: 2.03).

  Amorphous polyester resin 1 is dissolved in methyl ethyl ketone, an aqueous solution of anionic surfactant (sodium dodecyl sulfate) is added to this solution, and emulsified with a mechanical disperser (trade name: CLEARMIX, manufactured by M Technique Co., Ltd.). did. Methyl ethyl ketone was distilled off under reduced pressure from the obtained emulsion to obtain amorphous resin fine particles A (volume median particle size: 0.18 μm, embrittlement temperature: 20 ° C.).

<Preparation of crystalline resin fine particles a>
300 g of 1,6-hexanediol, 862 g of fumaric acid, 4 g of dibutyltin oxide and 1 g of hydroquinone were placed in a four liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple at 160 ° C. After reacting for 5 hours, the temperature was raised to 200 ° C. and reacted for 1 hour, and further reacted at 8.3 kPa until the desired crystallinity index was reached. Crystalline polyester resin 1 (softening temperature: 123 ° C., endothermic) The maximum peak temperature: 115 ° C. and the crystallinity index: 0.93) were obtained.

  Crystalline polyester resin 1 is dissolved in methyl ethyl ketone, an anionic surfactant (sodium dodecyl sulfate) aqueous solution is added to this solution, and emulsified with a mechanical disperser (trade name: CLEARMIX, manufactured by M Technique Co., Ltd.). . Methyl ethyl ketone was distilled off under reduced pressure from the obtained emulsion to obtain crystalline resin fine particles a (volume median particle size: 0.16 μm, embrittlement temperature: −13 ° C.).

[Mixed resin particle preparation process]
Amorphous resin fine particles A and crystalline resin fine particles a are added in an amount of 500 g, and the concentration is adjusted so that the weight ratio of the amorphous resin fine particles A and the crystalline resin fine particles a is 50:50. A mixed resin fine particle slurry in which the crystalline resin fine particles A and the crystalline resin fine particles a were mixed was prepared. This was freeze-dried to obtain a mixed resin fine particle 1 as a dry powder. The content of the crystalline resin fine particles a in the mixed resin fine particles 1 is 50% by weight. The volume median particle size of the mixed resin fine particles 1 was 35 μm.

[Cooling process, temperature adjustment process and adhesion process]
After removing moisture from the compressed air supplied from the compressor, the compressed air is supplied to first and second low-temperature thermostatic baths (trade name: TRL-107SLC, manufactured by Thomas Chemical Equipment Co., Ltd.). The temperature of methanol in the second low temperature thermostat was adjusted.

  In the 1st low temperature thermostat, the temperature adjustment of the supplied compressed air was performed using the heat exchanger. The temperature-controlled compressed air is used as the carrier gas. The set temperature of the first low-temperature thermostatic chamber at this time is −15 ° C., and this set temperature is the temperature of the carrier gas.

  In the second low-temperature thermostatic chamber, the temperature of the supplied compressed air is adjusted using a heat exchanger, and the flow rate of this compressed air is adjusted with a flow rate adjusting valve, while the powder transfer (input) device (trade name: By supplying to AeroV (Showa Carbonic Acid Co., Ltd.) and maintaining this state for 30 minutes or more, the internal temperature of the apparatus was stabilized at a predetermined set temperature (−15 ° C.). The mixed resin fine particles 1 are put into the powder conveying (feeding) device stabilized at a predetermined set temperature, and the temperature inside the device is monitored by a thermometer provided inside the device. The mixed resin fine particles 1 were cooled to a predetermined cooling temperature (−15 ° C.) by performing the temperature control and the flow rate adjustment of the compressed air.

  In a hybridization system according to the apparatus shown in FIG. 2 (trade name: NHS-1 type, manufactured by Nara Machinery Co., Ltd.), a temperature adjustment jacket is provided on the entire surface of the powder flow section and the stirring section to A temperature sensor was attached to the road. In the coating step, the temperature in the powder channel was adjusted to 45 ° C. 100 parts by weight of toner base particles were introduced into the powder flow path and the rotation speed was set to 8000 rpm to stabilize the flow state of the toner base particles in the powder flow path.

  10 wt.% Of the mixed resin fine particles 1 cooled to −15 ° C. from the powder conveying (input) device using a carrier gas cooled to −15 ° C. in the powder flow path in which the toner base particles are flowing. A part of the mixture was added and the rotary stirring was continued for 3 minutes. After that, by continuing the rotary stirring for 10 minutes, the crushed mixed resin fine particles were adhered to the surface of the toner base particles. In the attaching step, the peripheral speed at the outermost periphery of the rotating stirring means of the hybridization system was 100 m / sec.

[Spraying process and film forming process]
Ethanol (plasticized liquid) was sprayed at a spray rate of 0.5 g / min and an air flow rate of 5 l (liter) / min for 40 minutes to form mixed resin fine particles on the surface of the toner base particles. After stopping the ethanol spraying, the mixture was stirred for 5 minutes to obtain a capsule toner (volume median particle size: 7.2 μm, coefficient of variation: 25). The content of aggregated particles contained in this capsule toner was 1%.

  At this time, the discharge concentration of the plasticizing liquid discharged through the through hole and the gas discharge portion was stable at about 1.4 Vol%. The flow rate of air sent into the apparatus was adjusted to 5 l (liter) / min from the rotary shaft portion into the apparatus, and the total air flow from the two-fluid nozzle was 10 l (liter) / min.

  In the spraying step and the film forming step, the peripheral speed at the outermost periphery of the rotary stirring means was 100 m / sec. 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 °).

  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 and liquid gas discharge speed of the plasticizing liquid can be observed using a commercially available gas detector (trade name: XP-3110, manufactured by Shin Cosmos Electric Co., Ltd.).

  To 100 parts by weight of the capsule toner thus prepared, 2 parts by weight of hydrophobic silica particles (manufactured by Aerosil Co., Ltd., primary particle size 12 nm, HMDS treatment) are added as an external additive, and the rotational stirring means is operated at a peripheral speed. The capsule toner of Example 1 was obtained by mixing at 30 m / sec for 1 minute.

(Example 2)
A capsule toner of Example 2 was obtained in the same manner as in Example 1 except that the temperature of the carrier gas was changed from −15 ° C. to −5 ° C.

(Example 3)
[Resin fine particle preparation process]
<Preparation of amorphous resin fine particles A>
In the same manner as in Example 1, amorphous resin fine particles A were obtained.

<Preparation of crystalline resin fine particles b>
300 g of 1,6-hexanediol, 812 g of fumaric acid, 4 g of dibutyltin oxide and 1 g of hydroquinone were put into a 5 liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple at 160 ° C. After reacting for 5 hours, the temperature was raised to 200 ° C. and reacted for 1 hour, and further reacted at 8.3 kPa until the desired crystallinity index was reached. Crystalline polyester resin 2 (softening temperature: 113 ° C., endothermic) The maximum peak temperature: 109 ° C. and the crystallinity index: 0.96) were obtained.

  Crystalline polyester resin 2 is dissolved in methyl ethyl ketone, an aqueous solution of an anionic surfactant (sodium dodecyl sulfate) is added to this solution and emulsified with a mechanical disperser (trade name: CLEARMIX, manufactured by M Technique Co., Ltd.). . Methyl ethyl ketone was distilled off under reduced pressure from the obtained emulsion to obtain crystalline resin fine particles b (volume median particle size: 0.18 μm, embrittlement temperature: −19 ° C.).

[Mixed resin particle preparation process]
Mixed resin fine particles 2 were obtained in the same manner as in the mixed resin fine particle preparation step of Example 1 except that the crystalline resin fine particles b were used instead of the crystalline resin fine particles a. The content of the crystalline resin fine particles a in the mixed resin fine particles 2 is 50% by weight. The volume median particle size of the mixed resin fine particles 2 was 42 μm.

  In the subsequent steps, in the cooling step, the mixed resin fine particles 2 are used instead of the mixed resin fine particles 1, the cooling temperature of the mixed resin fine particles 2 is set to -20 ° C, and the temperature of the carrier gas is changed from -15 ° C to -20 ° C. A capsule toner of Example 3 was obtained in the same manner as Example 1 except that.

Example 4
Example 4 is the same as Example 3 except that the temperature of the mixed resin fine particles 2 is changed from -20 ° C to -25 ° C and the temperature of the carrier gas is changed from -20 ° C to -10 ° C in the cooling step. Capsule toner was obtained.

(Comparative Example 1)
In the cooling step, the temperature of the mixed resin fine particles 1 was changed from −15 ° C. to 0 ° C., and the temperature of the carrier gas was changed from −15 ° C. to −0 ° C. A capsule toner was obtained.

(Comparative Example 2)
Comparative Example 2 in the same manner as in Example 3 except that the temperature of the mixed resin fine particles 1 was changed from −20 ° C. to −15 ° C. and the temperature of the carrier gas was changed from −20 ° C. to −0 ° C. in the cooling step. Capsule toner was obtained.

  Table 1 shows the physical properties of the resin fine particles, and Table 2 shows the types of the amorphous resin fine particles and the crystalline resin fine particles in the mixed resin fine particles.

<Preparation of two-component developer>
The capsule toners of Examples and Comparative Examples and a ferrite core carrier having a volume average particle diameter of 60 μm were mixed so that the toner concentration became 7% to prepare a two-component developer.

  The following evaluation was performed using the above two-component developers including the capsule toners of Examples 1 to 4 and Comparative Examples 1 and 2.

[image quality]
Commercially available copying machines (trade name: MX-2300G, manufactured by Sharp Corporation) were each filled with the two-component developer containing the capsule toners of Examples and Comparative Examples. After adjusting to an image density ID of 12 using a spectrocolorimetric densitometer (trade name: X-Rite Model 939, manufactured by X-Rite Co., Ltd.), the image was developed under an environmental condition of a temperature of 20 ° C. and a humidity of 65%. A strip-shaped solid image was obtained. The number of white spots in the band-shaped solid image was visually counted to evaluate the image quality.

The image quality evaluation criteria are as follows.
A: Very good. White spots are not confirmed.
○: Good. One white spot is confirmed.
Δ: No problem in actual use. White spots are confirmed from 2 to 9 points.
X: Defect. 10 or more white spots are confirmed.
Table 3 shows the evaluation results of the image quality.

  From the results in Table 3, since the resin fine particles were sufficiently crushed in the examples, the capsule toner of the examples has a low content of aggregated particles and can suppress the generation of white spots in the band-shaped solid image. It can be seen that the image quality is good.

  From the comparison of the results of Examples 1 and 2 and the comparison of the results of Examples 3 and 4, the resin fine particles are more sufficiently when the temperature of both the resin fine particles and the carrier gas is lower than the embrittlement embrittlement temperature of the resin fine particles. It can be seen that it can be crushed. Moreover, it turns out that a more preferable result is obtained, so that the content rate of an aggregated particle is low.

  Further, from the result of the comparative example, when the content rate (weight basis) of the aggregated particles exceeds 4%, the number of white spots is increased particularly, resulting in an image defect. From this, it can be seen that the generation of white spots is related to the size of the particles containing no colorant.

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

Claims (7)

A cooling step for cooling the resin fine particles to a temperature below the embrittlement temperature;
In the rotary stirring device comprising a rotary stirring means and a powder flow path, the resin fine particles cooled in the cooling step in a powder flow path in which toner base particles containing a binder resin and a colorant are flowing The toner base particles and the resin fine particles are mixed under stirring while the temperature is maintained below the embrittlement temperature, and the resin fine particles are adhered to the surface of the toner base particles. An attaching step for obtaining attached toner mother particles;
And a film forming step of forming a resin coating layer on the surface of the toner base particles by continuing stirring until the resin fine particles on the surface of the toner base particles are formed into a film. Manufacturing method.   The method for producing a capsule toner according to claim 1, wherein the resin fine particles include a crystalline resin and an amorphous resin.   In the cooling step, the resin fine particles cooled to a temperature equal to or lower than the embrittlement temperature are transported to the powder flow path by a carrier gas having a temperature equal to or lower than the embrittlement temperature, and are injected into the powder flow path. The method for producing a capsule toner according to claim 1, wherein the capsule toner is produced.   The method for producing a capsule toner according to any one of claims 1 to 3, wherein in the cooling step, the resin fine particles are cooled to a temperature equal to or lower than the embrittlement temperature by a coolant.   The method for producing a capsule toner according to claim 4, wherein liquid nitrogen or an evaporated gas thereof is used as the coolant.   The spraying step of spraying a plasticizing liquid, which is a liquid for plasticizing the toner base particles and the resin fine particles, onto the resin fine particle-attached toner base particles under stirring is included as a subsequent step of the attaching step. The method for producing a capsule toner according to claim 1.   The capsule toner manufactured by the manufacturing method of the capsule toner as described in any one of Claims 1-6.