JP2012220645A - Method for manufacturing capsule toner, capsule toner, and two-component developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing capsule toners having low-temperature fixability, a high-temperature off-set resistance, and an anti-blocking property and capable of preventing toner filming, a capsule toner, and a two-component developer.SOLUTION: The method for manufacturing capsule toners includes: a step for manufacturing toner base particles for forming a release-agent layer; a step for manufacturing fine-particle-adhesion toner base particles; and a step for forming a resin coating layer. In the step for forming the resin coating layer, while spraying a liquid spray that is a liquid for plasticizing resin fine particles, the toner base particles for forming the release-agent layer on the surface of which the resin fine particles and inorganic particles are stuck, are stirred to form a film of the resin fine particles, and then the resin coating layer where the inorganic particles are dispersed in the resin is formed on the surface of the toner base particles for forming the release-agent layer.

Description

  The present invention relates to a capsule toner manufacturing method, a capsule toner, and a two-component developer.

  An image forming apparatus that forms an image using an electrophotographic system includes a photoconductor, a charging unit, an exposure unit, a developing unit, a transfer unit, a fixing unit, and a cleaning unit.

  The charging unit charges the surface of the photoreceptor, and the exposure unit irradiates the charged photoreceptor surface with signal light to form an electrostatic latent image corresponding to image information. The developing means supplies toner in the developer to the electrostatic latent image formed on the surface of the photoconductor to form a toner image, and the transfer means transfers the toner image formed on the surface of the photoconductor to a recording medium. Further, the fixing unit fixes the transferred toner image on the recording medium. The cleaning unit is, for example, a cleaning blade, and cleans the surface of the photoconductor by scraping the toner remaining on the surface of the photoconductor after the toner image is transferred.

  In such an image forming apparatus, an electrostatic latent image is developed using a one-component developer containing only toner or a two-component developer containing toner and carrier as a developer to form an image. The toner used here is resin particles that are granulated by dispersing a colorant and a wax as a release agent in a polyester-based binder resin as a matrix.

  Conventionally, a kneading and pulverizing method has been widely used as a toner manufacturing method. However, since the toner manufactured by the kneading and pulverizing method has an irregular shape with many irregularities on the surface, the fluidity of the toner tends to be lowered. In addition, the toner manufactured by the kneading and pulverization method has the crushed surface as it is as the toner particle surface, so the composition of the toner particle surface tends to be non-uniform, and the surface state of the toner particles can be controlled uniformly. difficult. If the composition of the toner particle surface is not uniform, problems such as fogging and toner scattering occur.

  In order to solve such problems, a wet method has been proposed in which a dispersion of toner raw materials is mixed and agglomerated to produce toner. However, since the wet method frequently uses a dispersion stabilizer and an aggregating agent, they are likely to remain on or inside the toner particles. For this reason, the toner obtained by the wet method tends to have low moisture resistance and chargeability, and in particular, the chargeability tends to become extremely unstable.

  In addition, with the trend toward higher image quality in recent years, there has been a tendency for the content of small-diameter toner in the two-component developer to increase as the particle size of the toner has progressed. In a two-component developer including a small particle size toner, the toner spent on the carrier and the accompanying charge deterioration of the developer occur due to cracking and shape change of the small particle size toner due to stress in the developing device. When toner spent and charging deterioration occur, developability and transferability are adversely affected and image quality is deteriorated.

  As described above, the toner base particles can be used as a toner that solves the problems of deterioration in fluidity, developability, transferability, and the like, and that the charging property is unstable, has excellent blocking resistance, and has various other functions. There is a capsule toner whose surface is coated with a resin coating layer.

  However, since the resin coating layer of the capsule toner generally uses resin fine particles having higher heat resistance than the toner base particles in order to improve the blocking resistance, the toner base particles are formed by the resin coating layer during fixing. It becomes difficult to melt and low temperature offset is likely to occur. Further, since the resin coating layer inhibits the release of the release agent from the inside of the toner base particles and high temperature offset is likely to occur, a sufficiently wide fixing temperature range (non-offset temperature range) cannot be obtained.

  Therefore, there is a capsule toner in which a release agent layer is formed on the surface of the toner base particles and a resin coating layer is further provided on the outer surface in order to improve all of the low-temperature fixability, high-temperature offset resistance and blocking resistance. .

  In Patent Document 1, a toner base particle is formed of a first resin, a colorant, and a first release agent, and a second release agent is fused on the surface thereof, and the release agent fusion layer is formed. A capsule toner obtained by fusing second resin particles on the surface of the toner to form a resin coating layer is disclosed.

JP 2006-58857 A

  However, since the capsule toner disclosed in Patent Document 1 is subjected to heat treatment when the second resin particles are fused to form the resin coating layer, the release agent constituting the release agent fusion layer Easy to bleed out. The capsule toner in which the release agent bleeds out has a problem that so-called toner filming is likely to occur, in which the toner component is fused to the surface of the photoreceptor.

  If the heating temperature at the time of forming the resin coating layer is lowered in order to prevent bleed-out of the release agent, the fusion of the second resin particles becomes incomplete and a strong resin coating layer cannot be formed.

  An object of the present invention is to provide a capsule toner manufacturing method, capsule toner, and two-component developer that have good low-temperature fixability, high-temperature offset resistance and blocking resistance and can prevent toner filming. .

The present invention relates to a release agent layer-forming toner base particle which forms a release agent layer-forming toner base particle by forming a release agent layer comprising a release agent on the surface of a toner base particle containing a binder resin and a colorant. Production process;
A fine particle-attached toner mother particle production step of attaching resin fine particles and inorganic fine particles to the surface of the release agent layer-forming toner mother particles;
The resin fine particles are formed into a film by agitating the release agent layer-forming toner base particles having the resin fine particles and the inorganic fine particles attached to the surface while spraying a spray liquid which is a liquid for plasticizing the resin fine particles. And a resin coating layer forming step of forming a resin coating layer in which the inorganic fine particles are dispersed in a resin on the surface of the release agent layer forming toner base particles. is there.

Further, in the present invention, the step of preparing the release agent layer-forming toner base particles includes
Mixing toner base particles and release agent particles to obtain first mixed particles;
A step of agitating the first mixed particles to cause the release agent particles to adhere to the surface of the toner base particles and to form a film, thereby forming a release agent layer on the surface of the toner base particles. Features.

Further, in the present invention, the fine particle-attached toner base particle preparation step includes
Mixing resin fine particles and inorganic fine particles to obtain second mixed particles;
Mixing the release agent layer-forming toner base particles and the second mixed particles to obtain third mixed particles;
A step of adhering the resin fine particles and the inorganic fine particles to the surface of the release agent layer forming toner base particles by stirring the third mixed particles.

  According to the present invention, in the resin coating layer forming step, the release agent layer forming toner base particles having the resin fine particles and the inorganic fine particles attached to the surface are stirred at a temperature lower than the melting point of the release agent particles. It is characterized by that.

  Further, in the resin coating layer forming step, the resin fine particles and the inorganic fine particles adhere to the surface at a temperature lower than the onset temperature of the release agent particles and lower than the softening temperature of the resin fine particles. The toner base particles for forming the release agent layer are agitated.

  In the present invention, the softening temperature of the resin fine particles is lower than the melting point of the release agent particles.

  The present invention is also characterized in that the average primary particle size of the inorganic fine particles is smaller than the average primary particle size of the resin fine particles.

Further, the present invention is a capsule toner produced by the method for producing capsule toner,
Toner base particles containing a binder resin and a colorant;
A release agent layer made of a release agent formed on the surface of the toner base particles;
A capsule toner comprising: a resin coating layer formed on a surface of the release agent layer, in which inorganic fine particles are dispersed in a resin.
The present invention also provides a two-component developer containing the capsule toner.

  According to the present invention, the method for producing a capsule toner includes a releasing agent layer-forming toner base particle preparation step, a fine particle-attached toner base particle preparation step, and a resin coating layer forming step. In the releasing agent layer forming toner base particle preparation step, a releasing agent layer formed of a releasing agent is formed on the surface of the toner base particle containing the binder resin and the colorant to obtain the releasing agent layer forming toner base particle. . In the fine particle-attached toner base particle preparation step, resin fine particles and inorganic fine particles are attached to the surface of the release agent layer-forming toner base particles. In the resin coating layer forming step, the resin fine particles are formed by stirring the release agent layer-forming toner base particles having the resin fine particles and the inorganic fine particles attached to the surface while spraying a spray liquid which is a liquid for plasticizing the resin fine particles. The resin coating layer in which the inorganic fine particles are dispersed in the resin is formed on the surface of the release agent layer forming toner base particles.

  In the resin coating layer forming step, the resin fine particles are released without heat treatment by stirring the release agent layer forming toner base particles having the resin fine particles and inorganic fine particles attached to the surface while spraying the spray liquid. Since the film can be formed on the surface of the toner layer forming toner base particles, bleeding out of the release agent during production can be suppressed. Accordingly, it is possible to obtain a capsule toner having good low-temperature fixability, high-temperature offset resistance and blocking resistance, and capable of preventing toner filming.

  According to the invention, the step of preparing the release agent layer forming toner base particles includes a step of obtaining the first mixed particles and a step of forming the release agent layer. In the step of obtaining the first mixed particles, the toner base particles and the release agent particles are mixed. In the release agent layer forming step, the first mixed particles are agitated to cause the release agent particles to adhere to the surface of the toner base particles and to form a film, thereby forming the release agent layer on the surface of the toner base particles.

  By performing the step of obtaining the first mixed particles, the toner base particles and the release agent particles can be uniformly mixed before the release agent particles are adhered to the surface of the toner base particles. A uniform release agent layer can be formed on the surface.

  According to the present invention, the fine particle-attached toner base particle preparation step includes a step of obtaining the second mixed particles, a step of obtaining the third mixed particles, and stirring the third mixed particles to form a release agent layer forming toner base. And a step of attaching resin fine particles and inorganic fine particles to the surface of the particles. In the step of obtaining the second mixed particles, the resin fine particles and the inorganic fine particles are mixed. In the step of obtaining the third mixed particles, the release agent layer forming toner base particles and the second mixed particles are mixed.

  By performing the step of obtaining the second mixed particles and the step of obtaining the third mixed particles, before the resin fine particles and the inorganic fine particles are adhered to the surface of the release agent layer forming toner base particles, the release agent layer forming toner base particles Since the resin fine particles and the inorganic fine particles can be uniformly mixed, the surface of the release agent layer forming toner base particles can be uniformly coated with the resin fine particles and the inorganic fine particles.

According to the invention, in the resin coating layer forming step, the release agent layer forming toner base particles having the resin fine particles and the inorganic fine particles attached to the surface are stirred at a temperature lower than the melting point of the release agent particles.
Thereby, the bleeding out of the release agent at the time of manufacture can be further suppressed.

  According to the invention, in the resin coating layer forming step, the release agent layer in which the resin fine particles and the inorganic fine particles adhere to the surface at a temperature lower than the onset temperature of the release agent particles and lower than the softening temperature of the resin fine particles. Stir the formed toner base particles.

  By being below the onset temperature of the release agent particles, it is possible to suppress the resin fine particles from being buried in the release agent layer during production. Therefore, bleeding of the release agent in the development process can be suppressed, and toner filming can be prevented. When the temperature is lower than the softening temperature of the resin fine particles, it is possible to further suppress the release of the release agent constituting the release agent layer by the softening of the resin fine particles during the production.

  According to the present invention, the softening temperature of the resin fine particles is lower than the melting point of the release agent particles. This prevents the resin fine particles from being embedded in the release agent layer even when the release agent layer forming toner base particles having the resin fine particles and inorganic fine particles attached to the surface are stirred in the resin coating layer forming step. it can.

  According to the invention, the average primary particle diameter of the inorganic fine particles is smaller than the average primary particle diameter of the resin fine particles.

  As a result, in the resin coating layer forming step, the impact force on the inorganic fine particles can be reduced by stirring the release agent layer-forming toner base particles having the resin fine particles and inorganic fine particles attached to the surface. It can prevent being buried in the agent layer.

  Further, according to the present invention, a capsule toner is produced from a toner base particle containing a binder resin and a colorant, which is manufactured by the capsule toner manufacturing method of the present invention, and a release agent formed on the surface of the toner base particle. And a resin coating layer formed on the surface of the release agent layer in which inorganic fine particles are dispersed in the resin. Therefore, the capsule toner has good low-temperature fixability, high-temperature offset resistance, and blocking resistance, and can prevent toner filming.

  According to the invention, since the two-component developer includes the capsule toner of the invention, the low-temperature fixing property, the high-temperature offset resistance and the blocking resistance are good, and toner filming can be prevented.

It is process drawing which shows the manufacturing method of the capsule toner which is one Embodiment of this invention. It is a front view which shows the structure of the resin coating layer forming apparatus 201 used with the manufacturing method of the capsule toner of this invention. It is the schematic sectional drawing which looked at the resin coating layer forming apparatus 201 shown in FIG. 2 from cut surface 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 toner base particle, a release agent layer formed on the surface of the toner base particle, and a resin coating layer formed on the surface of the release agent layer. Including.

(Toner mother particles)
The toner base particles include a binder resin and a colorant.
Amorphous polyester is used as the binder resin. An amorphous polyester resin is a resin having no clear melting point. Amorphous polyester resins generally have high resistance, so even if they are exposed on the toner surface, the influence on the charging stability can be kept small. On the other hand, a crystalline polyester resin is not preferred because it requires a large amount of energy for melting and cannot improve the toner fixability.

  The amorphous polyester is usually one or more selected from a divalent alcohol monomer and a trihydric or higher polyhydric alcohol monomer as a constituent monomer, a divalent carboxylic acid monomer and a trivalent or higher. Those obtained by polycondensation using at least one selected from these polycarboxylic acid monomers are used.

  Examples of the divalent alcohol monomer include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis (4- Hydroxyphenyl) propane, polyoxypropylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene (2.0) -2,2-bis Alkylene oxide adducts of bisphenol A such as (4-hydroxyphenyl) propane and polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, ethylene glycol, diethylene glycol, triethylene glycol, 1,2- Propylene glycol, 1,3-propylene glycol, 1,4-butanediol, ne Pentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A, Examples include propylene adducts of bisphenol A, ethylene adducts of bisphenol A, hydrogenated bisphenol A, and the like.

  Examples of the trihydric or higher polyhydric alcohol monomer include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4. -Butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxy Examples include methylbenzene.

  In the present invention, these dihydric alcohol monomers and trihydric or higher polyhydric alcohol monomers can be used alone or in combination.

  As the acid component, divalent carboxylic acid monomers such as maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, sebacic acid , Azelaic acid, malonic acid, n-dodecenyl succinic acid, n-dodecyl succinic acid, n-octyl succinic acid, isooctenyl succinic acid, isooctyl succinic acid, and anhydrides or lower alkyl esters of these acids.

  Examples of the trivalent or higher polyvalent carboxylic acid monomer include 1,2,4-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4. -Butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1 2,7,8-octanetetracarboxylic acid, pyromellitic acid, emporic trimer acid, their acid anhydrides, lower alkyl esters, and the like.

  In the present invention, these divalent carboxylic acid monomers and trivalent or higher polyvalent carboxylic acid monomers can be used alone or in combination.

  The method for producing the amorphous polyester in the present invention is not particularly limited, and can be produced by esterification or transesterification using the above-mentioned monomers.

  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 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, and the like.

  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 amount of the colorant used is not particularly limited, but is preferably 0.1 to 20 parts by weight, more preferably 0.2 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

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

  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 to 3 parts by weight, and 0.5 to 1.5 parts by weight with respect to 100 parts by weight of the binder resin. Is particularly preferred. In addition, the charge control agent may be used by being mixed in a coating layer made of resin fine particles in the coating step described later.

  The toner base particles of the present invention may contain known additives in addition to the binder resin, colorant and charge control agent.

  The volume average particle diameter of the toner base particles is preferably 3 μm or more and 10 μm or less, and more preferably 5 μm or more and 8 μm or less. When the volume average particle diameter of the toner base particles is 3 μm or more and 10 μm or less, a high-definition image can be stably formed over a long period of time. When the volume average particle diameter of the toner base particles is less than 3 μm, the toner base particles have a small particle diameter, and thus there is a risk of high charge and low fluidization. If the toner is highly charged and fluidized, the toner cannot be stably supplied to the photoconductor, which may cause background fogging and a decrease in image density. When the average particle diameter of the toner base particles exceeds 10 μm, the toner base particles have a large particle diameter, so that the layer thickness of the formed image increases, resulting in an image with remarkable graininess, and a high-definition image cannot be obtained. Further, as the particle diameter of the toner base particles increases, the specific surface area decreases and the charge amount of the toner decreases. When the charge amount of the toner is small, the toner is not stably supplied to the photoconductor, and there is a possibility that in-machine contamination due to toner scattering occurs.

(Release agent layer)
The release agent layer is formed by release agent particles. As the release agent used as a raw material for the release agent particles, a release agent commonly used in the art can be used, for example, petroleum wax such as paraffin wax and microcrystalline wax and derivatives thereof; Hydrocarbon synthetic waxes such as Tropsch wax, polyolefin wax (polyethylene wax, polypropylene wax, etc.), low molecular weight polypropylin wax and polyolefin polymer wax (low molecular weight polyethylene wax, etc.) and their derivatives; carnauba wax, rice wax and Candelilla wax and derivatives thereof, plant waxes such as wood wax; animal waxes such as beeswax and spermaceti; oil-based synthetic waxes such as fatty acid amides and phenol fatty acid esters Box; long-chain carboxylic acids and derivatives thereof; long-chain alcohols and derivatives thereof; silicone polymer; such as higher fatty acids.

  The derivatives include oxides, block copolymers of vinyl monomers and waxes, graft modified products of vinyl monomers and waxes, and the like.

  In this invention, 1 type of said mold release agent can be used individually or in combination of 2 or more types.

  In order to further exhibit the excellent effects of the present invention, the release agent particles preferably have a melting point of 70 to 110 ° C and an onset temperature of 60 to 100 ° C. More preferably, the melting point is 70 to 95 ° C and the onset temperature is 60 to 85 ° C.

  The onset temperature of the release agent particles is a temperature lower than the melting point of the release agent particles, and the “onset temperature” is a baseline on the lower temperature side than the endothermic peak corresponding to melting in the DSC curve. It means the temperature at the intersection of the straight line extended to the point and the tangent drawn at the point where the gradient is maximum with respect to the curve from the peak rising part to the apex. The specific measuring method will be described in detail in Examples.

  When the melting point and onset temperature of the release agent particles are within the above ranges, an image having a high image density and a very good image quality can be formed without impairing various physical properties of the toner. .

(Resin coating layer)
The resin coating layer is a layer in which inorganic fine particles are dispersed in the resin on the surface of the release agent layer, that is, the portion where the resin fine particles are formed and the portion where the inorganic fine particles are attached on the surface of the release agent layer. It is a layer mixed in the form of resin fine particles and inorganic fine particles.

  By forming such a resin coating layer on the surface of the release agent layer, it is possible to prevent the release agent from being exposed to the capsule toner surface due to mechanical stress during the development process. Filming can be prevented and offset resistance at the time of fixing is improved.

  As the resin used as the raw material for the resin fine particles, for example, a resin used for a toner material can be used, and examples thereof include polyester, acrylic resin, styrene resin, and styrene-acrylic copolymer. Among the resin exemplified above, the resin fine particles preferably include an acrylic resin and a styrene-acrylic copolymer in view of plasticization by a spray liquid described later. In addition, acrylic resins and styrene-acrylic copolymers have many advantages such as light weight and high strength, high transparency, low cost, and easy to obtain materials with uniform particle diameters.

  The resin used as the raw material for the resin fine particles may be the same type of resin as the binder resin contained in the toner base particles, or a different type of resin. In this case, it is preferable to use a different type of resin. When a different kind of resin is used as the resin fine particle raw material, the softening temperature of the resin fine particle resin is preferably higher than that of the binder resin contained in the toner base particles. . This can prevent the capsule toners from fusing with each other during storage, and improve storage stability.

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

  The average primary 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. The average primary particle diameter of the resin fine particles is more preferably 0.1 μm or more and 0.5 μm or less. When the average primary particle diameter of the resin fine particles is 0.05 μm or more and 1 μm or less, a protrusion having a suitable size is formed on the surface of the coating layer. As a result, the toner manufactured by the manufacturing method of the present embodiment is easily caught by the cleaning blade during cleaning, and the cleaning performance is improved.

  Considering plasticization by the spray liquid, the weight average molecular weight of the resin used as the raw material for the resin fine particles is preferably 10,000 or more and 50,000 or less.

  The softening temperature of the resin fine particles is preferably lower than the melting point of the release agent particles. Accordingly, even if the second mixed particle-adhered toner base particles are stirred in the resin coating layer forming step S5 described later, it is possible to prevent the resin fine particles from being embedded in the release agent layer at the time of manufacture. When the resin fine particles are embedded in the release agent layer, the release agent constituting the release agent layer is exposed to the toner surface, so that the release agent bleeds out during the development process, and toner filming on the photoreceptor occurs. To do.

  As the inorganic fine particles, silica and titanium oxide having an average primary particle diameter of 40 nm or more and 300 nm or less can be used, and the surface of these inorganic particles is subjected to a surface treatment with a silane coupling agent, a titanium coupling agent, or silicone oil. Inorganic particles imparted with hydrophobicity can be used. In particular, silica particles in which trimethylsilyl groups are introduced on the surface using hexamethyldisilazane (hereinafter sometimes referred to as HMDS) as a silane coupling agent are excellent in hydrophobicity and insulation and are immobilized on the surface. The encapsulated toner has a stable charge amount even in a high-humidity environment, and an excellent charging improvement effect can be obtained.

  If the average primary particle size of the inorganic fine particles is less than 40 nm, the gap between the plurality of inorganic fine particles arranged on the surface of the release agent layer becomes small, and it is estimated that the release agent does not easily leak out during fixing. Sexuality will deteriorate. Further, when the average primary particle diameter exceeds 300 nm, it is presumed that the electrostatic adhesive force is weakened and is likely to be detached from the toner, and there is a risk of causing a decrease in charge and photoconductor filming over time.

  Examples of such inorganic fine particles include TG-C413 (average primary particle size: about 50 nm), TG-C413 (average primary particle size: about 85 nm), and TG-C190 (average primary particles) manufactured by CABOT. Diameter: about 115 nm), TG-C-6020N (average primary particle diameter: about 200 nm), Teika MSN-005 (average primary particle diameter: about 80 nm), Nippon Aerosil Co., Ltd. RX-50 (average primary) Particle diameter: about 40 nm), Shin-Etsu Chemical Co., Ltd. X24-9163A (average primary particle diameter: about 110 nm), and the like.

  By dispersing the inorganic fine particles in the resin coating layer, bleeding out of the release agent at the time of production and in the development process can be suppressed.

  The average primary particle size of the inorganic fine particles is preferably smaller than the average primary particle size of the resin fine particles. Thereby, in the resin coating layer forming step S5, the impact force to the inorganic fine particles by stirring the second mixed particle-attached toner base particles can be reduced, so that the resin fine particles are prevented from being embedded in the release agent layer. be able to.

In the capsule toner of this embodiment, since the release agent layer is formed on the surface of the toner base particles, the capsule toner according to the above embodiment having excellent low-temperature fixability and excellent offset resistance. It is manufactured by the manufacturing method. The capsule toner obtained by the above-described method for producing a capsule toner is a composite particle layer in which a release agent layer is formed on the surface of the toner base particles and the surface of the release agent layer is composed of resin fine particles and inorganic fine particles at a low temperature. Is a capsule toner having both a wide fixing temperature range excellent in offset resistance and filming resistance.
A method for manufacturing the capsule toner of this embodiment 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 the present embodiment includes a toner base particle preparation step S1, a resin fine particle preparation step S2, a release agent layer forming toner base particle preparation step S3, and a second mixed particle-attached toner base particle preparation step. S4 and resin coating layer formation process S5 are included.

(1) Toner mother particle production step S1
In the toner base particle preparation step S1, toner base particles are prepared. The method for preparing the toner base particles is not particularly limited and can be performed by a known method. For example, dry methods such as a pulverization method, suspension polymerization method, emulsion aggregation method, dispersion polymerization method, dissolution suspension method And wet methods such as melt emulsification. Hereinafter, a method for producing toner base particles by a pulverization method will be described.

(Preparation 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.

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

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

  Any method may be used for drying the resin fine particles. For example, dry resin fine particles can be obtained by using a method such as hot air heat receiving drying, conduction heat transfer drying, far infrared drying, microwave drying, or the like. The resin fine particles are used as a material for forming a film on the surface of the release agent layer formed on the surface of the toner base particles in the subsequent resin coating layer forming step S5. By using resin fine particles as a film forming material on the surface of the release agent layer, for example, it is possible to prevent the occurrence of aggregation due to melting of low melting point components such as a release agent contained in the release agent layer forming toner during storage. it can. Further, for example, when the release agent layer-forming toner is coated by spraying a liquid in which resin fine particles are dispersed, the shape of the resin fine particles remains on the surface of the toner, so that the cleaning property is excellent as compared with a toner having a smooth surface. Toner can be obtained.

(3) Release agent layer forming toner base particle preparation step S3
In the release agent layer-forming toner base particle preparation step S3, a release agent layer is formed on the surface of the toner base particles to obtain release agent layer-formed toner base particles. This step includes a first mixed particle preparation step S3a and a release agent layer forming step S3b.

(3-1) First mixed particle preparation step S3a
In the first mixed particle preparation step S3a, the toner base particles and the release agent particles are mixed to obtain a first mixture in which these particles are uniformly mixed. By performing the first mixed particle preparation step S3a, the toner base particles and the release agent particles can be uniformly mixed before the release agent particles are attached to the surface of the toner base particles. A uniform release agent layer can be formed on the surface.

  For mixing, for example, a known device such as a V-type mixer (manufactured by Tokuju Kogakusho Co., Ltd.) or a double cone type mixer (manufactured by Dalton Co., Ltd.) can be used.

  The amount of the release agent particles added is not particularly limited, but is preferably 0.2 to 20 parts by weight, particularly preferably 0.5 to 10 parts by weight, and 1.0 to 8.0 with respect to 100 parts by weight of the binder resin. Part by weight is particularly preferred.

  If the amount of the release agent particles is within the above range, an image having a high image density and a very good image quality can be formed without impairing various physical properties of the capsule toner.

(3-2) Release agent layer forming step S3b
In the release agent layer forming step S3b, the first mixed particles are subjected to a stirring process, an impact force is applied to the first mixed particles, and the release agent layer is formed on the surface of the toner base particles. Formed toner mother particles are obtained.

Examples of equipment that can be used in this process include Henschel mixers (trade name, manufactured by Mitsui Mining Co., Ltd.), Supermixers (trade name, manufactured by Kawata Co., Ltd.), Mechanomyl (trade name, manufactured by Okada Seiko Co., Ltd.), and the like. Examples thereof include a mixing device of a type, ONGMILL (trade name, manufactured by Hosokawa Micron Corporation), a hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.), and a Cosmo system (trade name, manufactured by Kawasaki Heavy Industries, Ltd.).
The operating conditions of the apparatus may be appropriately set depending on the material of the first mixture, the type of apparatus, and the like.

(4) Second mixed particle-attached toner base particle preparation step S4
In the second mixed particle-attached toner base particle preparation step S4, which is a fine particle-attached toner base particle preparation step, the resin fine particles and the inorganic fine particles are attached to the surface of the release agent layer-forming toner base particles, and the second mixed particle-attached toner. Get mother particles. The second mixed particle-attached toner base particle preparation step S4 includes a second mixed particle preparation step S4a, a third mixed particle preparation step S4b, and a second mixed particle attachment step S4c.

(4-1) Second mixed particle preparation step S4a
In the second mixed particle preparation step S4a, resin fine particles and inorganic fine particles are mixed to obtain second mixed particles in which these particles are uniformly mixed.

  For the mixing, as in the first mixed particle preparation step S3a, for example, a known device such as a V-type mixer (manufactured by Tokuju Kogakusho Co., Ltd.) or a double cone type mixer (manufactured by Dalton Co., Ltd.) may be used. it can.

  The addition amount of the resin fine particles and inorganic fine particles is not particularly limited. However, since the entire surface of the release agent layer-forming toner base particles must be coated with the resin fine particles and the inorganic fine particles, the release agent layer-formed toner base particles 100 are used. It is preferable that 1 to 20 parts by weight of resin fine particles and 0.2 to 2 parts by weight of inorganic fine particles are used with respect to parts by weight. When the resin fine particles and the inorganic fine particles are used in such a ratio, the resin fine particles and the inorganic fine particles can be attached to the entire surface of the release agent layer-forming toner base particles, and the entire surface of the release agent layer-formed toner base particles A resin coating layer can be formed. As a result, it is possible to more reliably prevent toner filming on the photoreceptor, which is caused by leaching out of the low melting point component contained in the release agent layer forming toner base particles.

  When the addition amount of the resin fine particles is less than 1 part by weight, when the addition amount of the inorganic fine particles is small, the entire surface of the release agent layer cannot be coated. Since the mechanical impact force on the fine particles is increased and buried in the release agent layer, the release agent is exposed. In addition, even if the entire surface can be coated, the resin coating layer becomes thin, so that the release agent is likely to ooze out even during fixing. When the addition amount of the resin fine particles exceeds 20 parts by weight, the ratio of covering the surface of the release agent layer with the resin fine particles becomes too large, so that the release of the release agent is inhibited and the fixability of the capsule toner may be lowered. .

(4-2) Third mixed particle preparation step S4b
In the third mixed particle preparation step S4b, the release agent layer forming toner base particles and the second mixed particles are mixed to obtain third mixed particles in which these particles are uniformly mixed.

  For the mixing, as in the first mixed particle preparation step S3a, for example, a known device such as a V-type mixer (manufactured by Tokuju Kogakusho Co., Ltd.) or a double cone type mixer (manufactured by Dalton Co., Ltd.) may be used. it can.

  By performing the second mixed particle preparation step S4a and the third mixed particle preparation step S4b, before the resin fine particles and the inorganic fine particles are attached to the surface of the release agent layer forming toner base particles, the release agent layer forming toner base particles and Since the resin fine particles and the inorganic fine particles can be mixed uniformly, that is, so that any of the particles is not unevenly distributed locally, in the second mixed particle attaching step S4c, the release agent layer forming toner The surface of the mother particle can be uniformly coated with resin fine particles and inorganic fine particles.

(4-3) Second mixed particle adhesion step S4c
In the second mixed particle adhering step S4c, the third mixture is subjected to a stirring process, an impact force is applied to the third mixture, and the resin fine particles and the inorganic fine particles adhere to the surface of the release agent layer forming toner base particles. Two mixed particle-attached toner base particles are obtained. That is, the impact force is applied to the resin fine particles and the inorganic fine particles, the resin fine particles are crushed, and the resin fine particles and the inorganic fine particles are adhered (fixed) to the surface of the release agent layer-forming toner base particles. Adhering toner base particles are obtained.

Examples of devices that can be used in this step include, for example, Henschel mixer (trade name, manufactured by Mitsui Mining Co., Ltd.), super mixer (trade name, manufactured by Kawata Co., Ltd.), Mechanomyl, as in the release agent layer forming step S3b. (Trade name, manufactured by Okada Seiko Co., Ltd.) and other Henschel type mixing devices, ong mill (trade name, manufactured by Hosokawa Micron Co., Ltd.), hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.), Cosmo system (trade name, Kawasaki Heavy Industries, Ltd.).
The operating conditions of the apparatus may be appropriately set depending on the material of the third mixed particles, the type of apparatus, and the like.

(5) Resin coating layer forming step S5
In the resin coating layer forming step S5, while spraying a spray liquid which is a liquid for plasticizing resin fine particles, the second mixed particle-adhered toner base particles are stirred and flown in a powder flow path of an apparatus to be described later and subjected to impact. Giving power. Thus, the resin fine particles can be formed into a film, and a resin coating layer in which inorganic fine particles are dispersed in the resin can be formed on the surface of the release agent layer-forming toner base particles.

  In this step, the release agent layer forming toner base particles with resin fine particles and inorganic fine particles adhering to the surface are stirred while spraying the spray liquid, so that the resin fine particles are formed without heat treatment. Since the film can be formed on the surface of the toner base particles, bleeding out of the release agent at the time of production can be suppressed. Accordingly, it is possible to obtain a capsule toner having good low-temperature fixability, high-temperature offset resistance and blocking resistance, and capable of preventing toner filming.

  Examples of the apparatus that can be used in this step include a hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.), a resin coating layer forming apparatus described later, and the like.

  It is preferable that the rotary stirring means of the rotary stirring device in the resin coating layer forming step includes a rotary disk and a rotary shaft with rotary blades installed around.

<Resin coating layer forming device>
FIG. 2 is a front view showing the configuration of the resin coating layer forming apparatus 201 used in the capsule toner manufacturing method of the present invention. FIG. 3 is a schematic cross-sectional view of the resin coating layer forming apparatus 201 shown in FIG. 2 as viewed from the cutting plane line A200-A200.

  In the resin coating layer forming step S5, for example, a resin coating layer forming apparatus 201 shown in FIG. 2 is used, and a resin is applied to the surface of the release agent layer forming toner base particles by an impact force due to a synergistic effect of circulation and stirring in the apparatus 201. A coating layer is formed. The resin coating layer forming 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 charging unit 206, and a powder recovery unit. 207. The rotary stirring means 204 and the powder flow path 202 constitute a circulation means.

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

  The temperature in the powder flow path 202 is almost uniform in any part due to the flow of the release agent layer forming toner base particles. If the temperature in the flow path exceeds the glass transition temperature of the toner base particles or the onset temperature of the release agent particles, the release agent layer-forming toner base particles are excessively softened and there is a possibility that the particles are aggregated. On the other hand, when the temperature is lower than 30 ° C., the drying speed of the spray liquid described later is slowed, and the productivity is lowered. Therefore, in order to prevent the aggregation of the toner base particles, it is necessary to maintain the temperature of the powder flow path 202 and the rotary stirring means 204 described later below the glass transition temperature of the toner base particles and the onset temperature of the release agent particles. is there. Therefore, a temperature adjusting jacket, which will be described later, having an inner diameter larger than the outer diameter of the powder passage tube is disposed on at least a part of the outside of the powder passage 202 and the rotary stirring means 204.

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

  In the resin coating layer forming step S5, the peripheral speed of the outermost periphery of the rotary stirring means 204 is preferably set to 30 m / sec or more, and more preferably set to 50 m / sec or more. The outermost periphery of the rotary stirring means 204 is a portion 204a of the rotary stirring means 204 having the longest distance from the axis of the rotary shaft member 218 in the direction perpendicular to the direction in which the rotary shaft member 218 of the rotary stirring means 204 extends. By setting the peripheral speed at the outermost periphery of the rotating stirring means 204 during rotation to 30 m / sec or more, the second mixed particle-attached toner mother particles can be isolatedly flowed. If the peripheral speed at the outermost periphery is less than 30 m / sec, the toner base particles with the second mixed particles cannot be isolated and flown, so that the release agent layer-forming toner base particles can be uniformly coated with resin fine particles and inorganic fine particles. Disappear.

  It is preferable that the second mixed particle-attached toner base particles collide with the rotating disk 219 vertically. As a result, the second mixed particle-attached toner base particles are sufficiently stirred, so that the release agent layer-forming toner base particles can be coated more uniformly with the mixed particles of resin fine particles and inorganic fine particles, thereby forming a uniform resin coating layer. The yield of the encapsulated toner can be further improved.

(Spraying means)
The spraying means 203 is provided so as to be inserted through an opening formed in the outer wall of the powder flow path 202, and is closest to the opening 211 in the flow direction of the second mixed particle-attached toner base particles in the powder flow portion 209. It is provided in the powder flow part on the side.

  The spray means 203 sprays the spray liquid toward the second mixed particle-attached toner base particles. The spray means 203 is a liquid storage section that stores a liquid, a carrier gas supply section that supplies a carrier gas, and a mixture obtained by mixing the liquid and the carrier gas in the powder channel 202 as a spray liquid. A two-fluid nozzle that sprays toward the toner base particles with two mixed particles.

  Compressed air or the like can be used as the carrier gas. The spray liquid fed to the spraying means 203 at a constant flow rate by the liquid feed pump and spread by the spraying means 203 spreads on the surface of the second mixed particle-attached toner base particles.

(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, the temperature inside the powder flow path 202 and outside the rotary stirring means 204 can be controlled to a temperature at which the release agent layer-forming toner base particles and resin fine particles are not softened and deformed. In addition, in the resin coating layer forming step S5, the variation in temperature applied to the release agent layer forming toner base particles, resin fine particles, inorganic fine particles and liquid is reduced, and the stable flow state of the second mixed particle-attached toner base particles is maintained. Is possible.

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

  Moreover, in the powder flow part 209 downstream from the spraying means 203, the sprayed liquid does not dry and remains, and if the temperature is not appropriate, the drying speed becomes slow and the liquid tends to stay. When the second mixed particle-adhered toner base particles come into contact with this, the second mixed particle-adhered toner base particles easily 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 near the opening 210, the second mixed particle-attached toner mother particles flowing into the stirring unit 208 collide with the second mixed particle-attached toner mother particles flowing in the stirring unit 208 by stirring by the rotary stirring unit 204. The collided toner particles adhering to the second mixed particles are likely to adhere to the vicinity of the opening 210. Therefore, by providing the temperature adjustment jacket at the portion where the second mixed particle-adhered toner base particles are likely to adhere, the adhesion of the second mixed 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 the second mixed particle-attached toner base particles, a supply pipe 212 that communicates the hopper with the powder flow path 202, and an electromagnetic valve 213 that is provided in the supply pipe 212. Prepare. The second mixed particle-attached toner mother particles supplied from the hopper are supplied to the powder flow path 202 through the supply pipe 212 in a state where the flow path in the supply pipe 212 is opened by the electromagnetic valve 213. The second mixed particle-adhered toner mother particles supplied to the powder flow path 202 flow in a constant powder flow direction by stirring by the rotary stirring means 204. In addition, when the flow path in the supply pipe 212 is closed by the electromagnetic valve 213, the second mixed particle-attached toner base 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 flowing through the powder flow path 202 is collected in the collection tank 215 through the collection pipe 216. Further, 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 liquid that does not dissolve the resin fine particles and has the effect of plasticizing is not particularly limited. However, since the liquid needs to be removed from the second mixed particle-attached toner base particles after spraying, it is preferably a liquid that easily evaporates. Such a liquid preferably contains water or a lower alcohol.

  Examples of the lower alcohol include methanol, ethanol, propanol and the like. When the spray liquid contains such a lower alcohol, the wettability to the second mixed particle-attached toner base particles can be improved, and a resin coating layer is formed on the entire surface or most of the surface of the release agent layer-forming toner base particles. It becomes easier. Further, the plasticized resin fine particles are deformed by an external force, and a uniform resin coating layer can be formed on the surface of the release agent layer forming toner base particles. Further, the drying time for removing the spray liquid can be further shortened. Further, the drying time when removing the spray liquid can be further shortened, and aggregation of the second mixed particle-attached toner base particles can be suppressed.

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

  The spray liquid is not limited to the above-mentioned ones. For example, alcohols such as butanol, diethylene glycol and glycerin, ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate may be used. .

  The spray liquid is gasified so that the inside of the powder channel 202 has a constant gas concentration, and the gasified spray liquid is preferably discharged out of the powder channel 202 through the through hole 221. Thereby, the concentration of the gasified liquid in the powder flow path 202 can be kept constant, and the liquid drying rate can be increased as compared with the case where the concentration is not kept constant. Therefore, the capsule toner in which the undried spray liquid remains is prevented from adhering to other capsule toner, the aggregation of the capsule toner is suppressed, and the yield of the capsule toner having a uniform resin coating layer is further improved. be able to.

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

  In the present embodiment, it is preferable to start spraying after the flow rate of the second mixed particle-attached toner base particles is stabilized in the powder flow path 202. As a result, the spray liquid can be uniformly sprayed onto the second mixed particle-attached toner base particles, and the yield of the capsule toner on which the uniform resin coating layer is formed can be improved.

  In the resin coating layer forming step S5, the rotating fine stirring means 204 is continuously stirred at a predetermined temperature until the resin fine particles are softened and formed into a film, and the second mixed particle-attached toner mother particles are caused to flow, thereby releasing the resin fine particles. The film is formed on the surface of the toner layer forming toner base particles.

  The temperature in the resin coating layer forming step S5 is preferably 30 ° C. or higher and lower than the melting point of the release agent particles. Thereby, the bleeding out of the release agent due to the release agent layer melting at the time of production can be further suppressed.

  Further, the temperature in the resin coating layer forming step S5 is more preferably 30 ° C. or more, the onset temperature of the release agent particles or less, and less than the softening temperature of the resin fine particles.

  By being below the onset temperature of the release agent particles, it is possible to suppress the resin fine particles from being buried in the release agent layer during production. Therefore, bleeding of the release agent in the development process can be suppressed, and toner filming can be prevented. When the temperature is lower than the softening temperature of the resin fine particles, it is possible to suppress the release of the release agent that forms the release agent layer due to the softening of the resin fine particles during production. In this embodiment, the glass transition temperature of the binder resin in the toner base particles is set to a temperature lower than the onset temperature of the release agent particles. Therefore, the temperature in the resin coating layer forming step S5 is set to be equal to or lower than the glass transition temperature of the binder resin in the toner base particles.

After the resin coating layer is formed on the surface of the release agent layer-forming toner base particles, the spray liquid is removed. The spray liquid is removed by vaporizing the spray liquid with a dryer, for example. For removing the spray liquid, for example, a commonly used dryer such as a hot air receiving dryer, a conductive heat transfer dryer, or a freeze dryer is used. However, a hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.) is used. It is desirable to stop the supply of the sprayed liquid and evaporate and dry with stirring for a certain period of time.
Thereby, the capsule toner of the present invention is obtained.

  Such a resin coating layer forming apparatus 201 is not limited to the above-described 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 a temperature adjustment jacket is provided on the entire outer surface of the powder flow part 209 and the stirring part 208, the adhesion of the second mixed particle-attached toner base particles to the inner wall of the powder flow path 202 can be more reliably prevented. Can do.

  Further, instead of the resin coating layer forming apparatus 201, a commercially available stirring apparatus and spraying means can be combined. As a commercially available stirring apparatus provided with a powder flow path and rotating stirring means, for example, a hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.) and the like can be mentioned. By attaching a liquid spray unit in such a stirring device, the resin coating layer forming device 201 can be used.

  In addition, in the series of manufacturing flows, in consideration of the production efficiency of the capsule toner, since it is required to suppress the yield reduction due to the recovery loss, the second mixed particle-attached toner base particle preparation step S4 and the resin coating layer forming step S5 are required. Are preferably performed continuously in the same apparatus.

3. Two-component developer The capsule toner produced as described above can be mixed with a carrier and used as a two-component developer.

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

  Known coating materials can be used, such as polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone 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 diameter of the carrier is not particularly limited, but is preferably 10 to 100 μm, and more preferably 20 to 50 μm, in consideration of high image quality.

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 volume resistivity is low, the carrier is charged when a bias voltage is applied to the developing sleeve, and the carrier particles easily adhere to the photoreceptor. Further, breakdown of the bias voltage is likely to occur.

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

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

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In the following, “part” means “part by weight” unless otherwise specified. Glass transition temperature (Tg) and softening temperature (Ts) of resin in Examples and Comparative Examples, melting point (Tm) and onset temperature of release agent particles, volume average particle diameter and coefficient of variation of toner base particles, release agent The volume average particle diameter of the particles and the average primary particle diameter of the resin fine particles and the inorganic fine particles were measured as follows.

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

[Softening temperature of resin]
Using a flow characteristic evaluation apparatus (trade name: Flow Tester CFT-100C, manufactured by Shimadzu Corporation), a load of 20 kgf / cm ² (9.8 × 10 ⁵ Pa) was applied while heating 1 g of a sample at a heating rate of 6 ° C. per minute. In the flow curve obtained by pressurizing in (3), the temperature when moving from the solid region to the transition region was defined as the softening temperature (Ts). The discharge hole of the die from which the sample flows out has a diameter of 1 mm and a length of 1 mm.
[Weight average molecular weight of resin used as raw material for resin fine particles]
Using a GPC apparatus (trade name: HLC-8220GPC, manufactured by Tosoh Corporation), a 0.25 wt% tetrahydrofuran solution of the sample is used as a sample solution at a temperature of 40 ° C., and the injection amount of the sample solution is 200 μL. Asked. The weight average molecular weight Mw was determined from the obtained molecular weight distribution curve. The molecular weight calibration curve was prepared using standard polystyrene.

[Melting point and onset temperature of release agent particles]
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 defined as the melting point (Tm) of the release agent particles. In the obtained DSC curve, draw a line where the baseline is extended to the high temperature side from the endothermic peak corresponding to melting and a point where the slope is maximum with respect to the curve from the rising part to the peak of the peak. The temperature at the intersection with the tangent line was defined as the onset temperature.

[Volume average particle diameter and coefficient of variation of toner base particles and capsule toner]
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), and an ultrasonic dispersion device (trade name: UH-50, manufactured by SMT Co., Ltd.) is used. A dispersion treatment was performed at a frequency of 20 kHz for 3 minutes 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.
CV value (%) = (standard deviation in volume particle size distribution / volume average particle diameter) × 100

[Volume average particle diameter of release agent particles]
Using a laser diffraction / scattering particle size distribution measuring device (trade name: LA-920, manufactured by Horiba, Ltd.), the particle size was measured as a 50% frequency particle size (median diameter) on a volume basis.

[Average primary particle diameter of resin fine particles and inorganic fine particles]
Taking 100 images of resin fine particles magnified 50000 times with a scanning electron microscope (trade name: S-4300SE / N, manufactured by Hitachi High-Technologies Corporation) while changing the field of view, and analyzing the resin fine particles by image analysis The diameter (the length of the line segment obtained by measuring the dimensions in a certain direction and dividing the particle area into two) was measured. A particle size distribution was obtained by calculating a frequency ratio with an arbitrary particle size from the obtained measured value. In this particle size distribution, the particle diameter at which the cumulative number ratio was 50% was defined as the average primary particle diameter of the resin fine particles. The average primary particle size of the inorganic fine particles was calculated in the same manner.

Example 1
[Toner mother particle production step S1]
Polyester resin (trade name: Toughton, Kao Corporation, glass transition temperature 60 ° C.)
100 parts by weight Colorant (copper phthalocyanine, CI pigment blue 15: 3) 5 parts by weight Charge control agent (trade name: Bontron E84, manufactured by Orient Chemical Industry Co., Ltd.) 2 parts by weight

  The above raw materials were mixed and dispersed for 3 minutes using a Henschel mixer, and then melt-kneaded and dispersed using a twin screw extruder (trade name: PCM-30, manufactured by Ikegai Co., Ltd.). The operating conditions of the twin screw extruder were a cylinder set temperature of 110 ° C., a barrel rotation speed of 300 rpm, and a raw material supply speed of 20 kg / hour. The obtained toner kneaded product was cooled with a cooling belt and then coarsely pulverized with a speed mill having a φ2 mm screen. This coarsely pulverized product is finely pulverized with a jet type pulverizer (trade name: IDS-2, manufactured by Nippon Pneumatic Industry Co., Ltd.), and further classified with an elbow jet classifier (product name, manufactured by Nippon Steel Mining Co., Ltd.). Thus, toner base particles (volume average particle diameter 6.9 μm, variation coefficient 22) were obtained.

[Resin fine particle preparation step S2]
10 g of styrene-acrylic acid-butylacrylic acid copolymer resin (trade name: SK540, weight average molecular weight 20000), manufactured by Sanyo Chemical Industries, Ltd., and surfactant polyoxyethylene alkyl ether (trade name: Emulgen 1108, Kao) 5 g of distilled water and 1985 g of distilled water are charged into a high-pressure homogenizer while being heated to 95 ° C., and aqueous resin fine particles (glass transition temperature 64 ° C., softening temperature 85.3 ° C., average primary particle size 115 nm) are obtained. A dispersion (solid content concentration 5%) was obtained. This was dehydrated and dried using a Fujisaki dryer MDL-050 (trade name, manufactured by Fujisaki Electric Co., Ltd.) to produce resin fine particles.

[Releasing Agent Layer-Forming Toner Base Particle Preparation Step S3]
<First Mixed Particle Preparation Step S3a>
100 parts by weight of toner base particles prepared in toner base particle preparation step S1 and release agent particles made of Fischer-Tropsch wax (trade name: FNP0090, manufactured by Nippon Seiki Co., Ltd., melting point 90 ° C., onset temperature 82 ° C., 1 part by weight of a volume average particle diameter of 150 nm was charged into a Henschel mixer 20B (manufactured by Mitsui Mining Co., Ltd.) and mixed for 3 minutes at a peripheral speed of a stirring blade of 20 m / sec to prepare first mixed particles.

<Releasing agent layer forming step S3b>
The first mixed particles prepared in the first mixed particle preparation step S3a are put into a hybridization system (trade name: NHS-1 type, manufactured by Nara Machinery Co., Ltd.) according to the apparatus shown in FIG. Mixing for 3 minutes gave toner base layer forming toner mother particles.

[Second mixed particle-attached toner base particle preparation step S4]
<Second Mixed Particle Preparation Step S4a>
100 parts by weight of resin fine particles and inorganic fine particles (hydrophobic silica fine particles, trade name: TG-C413, manufactured by CABOT, average primary particle diameter: about 85 nm) are added to Henschel mixer 20B (manufactured by Mitsui Mining Co., Ltd.). The mixture was mixed for 3 minutes at a stirring blade peripheral speed of 20 m / sec to prepare second mixed particles.

<Third mixed particle preparation step S4b>
100 parts by weight of the release agent layer forming toner base particles prepared in the release agent layer forming toner base particle preparation step S3 and 7.5 parts by weight of the second mixed particles prepared in the second mixed particle preparation step S4a 20B (made by Mitsui Mining Co., Ltd.) and mixed for 3 minutes at a peripheral speed of the stirring blade of 20 m / sec to prepare third mixed particles.

<Second mixed particle attaching step S4c>
The third mixed particles prepared in the third mixed particle preparation step S4b are put into a hybridization system (trade name: NHS-1 type, manufactured by Nara Machinery Co., Ltd.) according to the apparatus shown in FIG. The mixture was mixed for 5 minutes to obtain second mixed particle-attached toner base particles.

[Resin coating layer forming step S5]
While maintaining the rotational speed of the hybridization system at 8000 rpm, the second mixed particle-attached toner base particles are sprayed with ethanol at a spraying rate of 0.5 g / min and an air flow rate of 5 L / min for 40 minutes, and the resin fine particles are released into the release agent layer. A film was formed on the surface of the formed toner base particles. After stopping the ethanol spraying, the mixture was stirred for 5 minutes to obtain the capsule toner of Example 1 (volume average particle size 7.0 μm, variation coefficient 23).

  The temperature adjusting jacket was provided on the entire surface of the powder flow section and the stirring section wall. A temperature sensor was attached to the powder channel, and the temperature of the powder flow part and the stirring part was adjusted to 45 ° C. 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 °).

  At this time, the air flow rate to be sent into the device was adjusted to 5 L (liter) / min from the rotary shaft portion into the device, and the total air flow rate from the two-fluid nozzle was 10 L / min.

(Example 2)
The release agent particles are changed to release agent particles made of carnauba wax (manufactured by Toa Kasei Co., Ltd., volume average particle diameter 100 nm, melting point 84 ° C., onset temperature 70 ° C.), and the resin fine particles have a glass transition temperature of The capsule toner of Example 2 (volume average particle diameter of 7.0 μm, softening temperature is changed to resin fine particles (average primary particle diameter of 115 nm) having a softening temperature of 82.7 ° C. in the same manner as in Example 1. A coefficient of variation 23) was obtained.

(Example 3)
The same as in Example 1 except that the release agent particles were changed to release agent particles made of carnauba wax (manufactured by Toa Kasei Co., Ltd., volume average particle size 100 nm, melting point 84 ° C., onset temperature 70 ° C.). Thus, the capsule toner of Example 3 (volume average particle diameter 7.0 μm, coefficient of variation 23) was obtained.

Example 4
The capsule toner of Example 4 was the same as Example 1 except that the inorganic fine particles were changed to hydrophobic silica (trade name: X24-9163A, average primary particle size: about 110 nm) manufactured by Shin-Etsu Chemical Co., Ltd. A volume average particle diameter of 7.0 μm and a coefficient of variation of 23) were obtained.

(Example 5)
The capsule toner (volume average) of Example 5 was the same as Example 1 except that the inorganic fine particles were changed to hydrophobic silica (trade name: TG-C190, average primary particle size: about 115 nm) manufactured by CABOT. A particle diameter of 7.0 μm and a coefficient of variation of 23) were obtained.

(Example 6)
The capsule toner of Example 6 was prepared in the same manner as in Example 1 except that the inorganic fine particles were changed to hydrophobic silica (trade name: TG-C-6020N, average primary particle size: about 200 nm) manufactured by CABOT. A volume average particle diameter of 7.0 μm and a coefficient of variation of 23) were obtained.

(Comparative Example 1)
A capsule toner was obtained in the same manner as in Example 1 except that the second mixed particle preparation step S4a was not performed and only the resin fine particles were used as the second mixed particles in the third mixed particle preparation step S4b.

  100 parts by weight of the capsule toner and 1.3 parts by weight of inorganic fine particles (hydrophobic silica fine particles, trade name: TG-C413, manufactured by CABOT, average primary particle size: about 85 nm) are added to a Henschel mixer 20B (Mitsui Mining Co., Ltd.). The mixture was mixed for 3 minutes at a peripheral speed of the stirring blade of 20 m / sec to obtain a capsule toner (volume average particle diameter 7.0 μm, variation coefficient 23) of Comparative Example 1.

(Comparative Example 2)
The release agent particles are changed to release agent particles made of carnauba wax (manufactured by Toa Kasei Co., Ltd., volume average particle diameter 100 nm, melting point 84 ° C., onset temperature 70 ° C.), and the second mixed particle preparation step S4a is performed. Without performing this, a capsule toner was obtained in the same manner as in Example 1 except that only the resin fine particles were used as the second mixed particles in the third mixed particle preparation step S4b.

  100 parts by weight of the capsule toner and 1.3 parts by weight of inorganic fine particles (hydrophobic silica fine particles, trade name: TG-C413, manufactured by CABOT, average primary particle size: about 85 nm) are added to a Henschel mixer 20B (Mitsui Mining Co., Ltd.). And mixed for 3 minutes at a peripheral speed of the stirring blade of 20 m / sec to obtain a capsule toner of Comparative Example 2 (volume average particle size 7.0 μm, coefficient of variation 23).

(Comparative Example 3)
In the second mixed particle preparation step S4a, the release agent layer forming toner mother particle preparation step S3 is not performed, and the resin fine particles 100 parts by weight and the inorganic fine particles (hydrophobic silica fine particles, trade name: TG-C413, manufactured by CABOT, 20 parts by weight of average primary particle size: about 85 nm) and 10 parts by weight of release agent particles made of Fischer-Tropsch wax (trade name: FNP0090, manufactured by Nippon Seiki Co., Ltd., melting point 90 ° C., onset temperature 82 ° C.) In the same manner as in Example 1 except that the second mixed particles were prepared by mixing for 3 minutes at a peripheral speed of the stirring blade of 20 m / sec. The capsule toner of Comparative Example 3 (volume average particle diameter 7.0 μm, coefficient of variation 23) was thus obtained.

(Comparative Example 4)
In the second mixed particle preparation step S4a, the release agent layer-forming toner base particle preparation step S3 is not carried out, and the release agent particles comprising 100 parts by weight of resin fine particles and Fischer-Tropsch wax (trade name: FNP0090, Nippon Seiki) 10 parts by weight made by Co., Ltd., melting point 90 ° C., onset temperature 82 ° C.) are put into Henschel mixer 20B (Mitsui Mining Co., Ltd.) and mixed for 3 minutes at a peripheral speed of the stirring blade of 20 m / sec. A capsule toner was obtained in the same manner as in Example 1 except that the second mixed particles were prepared.

  100 parts by weight of the capsule toner and 1.3 parts by weight of inorganic fine particles (hydrophobic silica fine particles, trade name: TG-C413, manufactured by CABOT, average primary particle size: about 85 nm) are added to a Henschel mixer 20B (Mitsui Mining Co., Ltd.). And mixed for 3 minutes at a peripheral speed of the stirring blade of 20 m / sec to obtain a capsule toner of Comparative Example 4 (volume average particle size 7.0 μm, coefficient of variation 23).

(Preparation of two-component developer)
The capsule toners of Examples 1 to 6 and Comparative Examples 1 to 4 and a ferrite carrier having a volume average particle diameter of 45 μm are mixed with a V-type mixer (trade name: V-5, manufactured by Tokuju Kogakusho Co., Ltd.). The two-component developers having a toner concentration of 7% were prepared by mixing for 40 minutes.

  Using the obtained two-component developers including the capsule toners of Examples 1 to 6 and Comparative Examples 1 to 4, evaluation was performed as follows.

[Film resistance]
The two-component developer was filled in a commercially available copying machine (trade name: MX-2300G, manufactured by Sharp Corporation), and an aging test by continuous image printing with a printing rate of 5% was performed. At that time, a solid image was printed every 1000 sheets printed, and the total number of printed sheets at which film-like image omission began to be observed was examined.

Filming resistance was evaluated according to the following criteria.
A: Very good. The total number of printed sheets when filming occurs is 200000 (200K) or more.
○: Good. The total number of printed sheets when filming occurs is 150K or more and less than 200K.
Δ: No practical problem. The total number of printed sheets when filming occurs is 100K or more and less than 150K.
X: Defect. The total number of printed sheets when filming occurs is less than 100K.

The evaluation results are shown in Table 1.

  In the capsule toners of Examples 1, 2, and 4, it is presumed that the resin fine particles are less likely to be embedded in the release agent layer by using resin fine particles having a softening temperature lower than the melting point of the release agent. Further, by making the average primary particle diameter of the inorganic fine particles smaller than the average primary particle diameter of the resin fine particles, the mechanical impact force acting on the inorganic fine particles can be alleviated, and the inorganic fine particles are less likely to be buried in the release agent layer. It is presumed that As a result, bleeding out of the release agent was suppressed, and high filming resistance was obtained. Further, as a result of evaluating the fixing property, it was found that sufficient offset resistance was obtained.

  Since the capsule toner of Example 3 uses resin fine particles having a softening temperature slightly higher than the melting point of the release agent particles, the resin fine particles are slightly embedded in the release agent layer as compared with the capsule toners of Examples 1 and 2. The total number of printed sheets at the time of filming is relatively small, but it is at a level that does not cause a problem in practice. Further, as a result of evaluating the fixing property, it was found that sufficient offset resistance was obtained.

  In the capsule toners of Examples 5 and 6, since the average primary particle diameter of the inorganic fine particles is larger than the average primary particle diameter of the resin fine particles, the mechanical impact force acting on the inorganic fine particles is increased, and the inorganic fine particles are released from the mold. It is presumed that it became easy to be buried in the drug layer. For this reason, the total number of printed sheets at the time of filming is relatively small, but it is at a level that causes no practical problems.

  In the capsule toner of Comparative Example 1, since the inorganic fine particles adhere to the surface of the resin coating layer, it is presumed that the inorganic fine particles are easily detached from the capsule toner due to mechanical stress received inside the developing unit. Therefore, bleeding out of the release agent is likely to occur, and it is considered that filming occurred with a small total number of printed sheets.

  In the capsule toner of Comparative Example 2, since the inorganic fine particles are adhered to the surface of the resin coating layer and the resin fine particles having a softening temperature slightly higher than the melting point of the release agent particles are used, the resin fine particles are used as the release agent layer. It is easy to be buried. Therefore, it is considered that bleeding out of the release agent is more likely to occur, and filming has occurred with a smaller total number of printed sheets.

  In the capsule toner of Comparative Example 3, the release agent layer is not formed, and the release agent particles are mixed with the resin fine particles and the inorganic fine particles and adhered to the surface of the toner base particles. It is considered that the filming resistance is deteriorated.

  In the capsule toner of Comparative Example 4, the inorganic particles are adhered after the toner base particles are coated with the mixed particles of resin fine particles and release agent particles. Therefore, it is presumed that the inorganic fine particles are easily detached from the capsule toner, and the exposure of the release agent becomes remarkable. Therefore, it is considered that the filming resistance has deteriorated.

DESCRIPTION OF SYMBOLS 201 Resin coating layer forming apparatus 202 Powder flow path 203 Spraying means 204 Rotating stirring means 206 Powder input part 207 Powder recovery part 208 Stirring part 208a One side surface of the stirring part 208 in the axial direction 208b One axial side of the stirring part 208 208c Side surface 208c perpendicular to surface 208a The other surface 209 in the axial direction of the stirring unit 208 209 Powder flow-through portion 210, 211 Opening portion 212 Supply pipe 213, 217 Solenoid valve 215 Collection tank 216 Collection pipe 218 Rotating shaft member 219 Disc shape Rotating plate 220 Plural stirring blades 221 Through hole 222 Gas discharge part A200 Cutting plane line θ Angle formed by liquid spraying direction and powder flow direction Φ Spreading angle of sprayed liquid

Claims (9)

A step of forming a release agent layer-forming toner base particle by forming a release agent layer comprising a release agent on the surface of the toner base particle containing a binder resin and a colorant to obtain a release agent layer-forming toner base particle;
A fine particle-attached toner mother particle production step of attaching resin fine particles and inorganic fine particles to the surface of the release agent layer-forming toner mother particles;
The resin fine particles are formed into a film by agitating the release agent layer-forming toner base particles having the resin fine particles and the inorganic fine particles attached to the surface while spraying a spray liquid which is a liquid for plasticizing the resin fine particles. And a resin coating layer forming step of forming a resin coating layer in which the inorganic fine particles are dispersed in a resin on the surface of the release agent layer forming toner base particles. The release agent layer forming toner base particle preparation step includes:
Mixing toner base particles and release agent particles to obtain first mixed particles;
A step of agitating the first mixed particles to cause the release agent particles to adhere to the surface of the toner base particles and to form a film, thereby forming a release agent layer on the surface of the toner base particles. The method for producing a capsule toner according to claim 1. The fine particle-attached toner base particle preparation step includes:
Mixing resin fine particles and inorganic fine particles to obtain second mixed particles;
Mixing the release agent layer-forming toner base particles and the second mixed particles to obtain third mixed particles;
The step of adhering the resin fine particles and the inorganic fine particles to the surface of the release agent layer-forming toner base particles by stirring the third mixed particles is provided. Manufacturing method for capsule toner.   In the resin coating layer forming step, the release agent layer forming toner base particles having the resin fine particles and the inorganic fine particles attached to the surface are stirred at a temperature lower than the melting point of the release agent particles. The method for producing a capsule toner according to claim 2.   In the resin coating layer forming step, the release agent layer formation in which the resin fine particles and the inorganic fine particles adhere to the surface at a temperature lower than the onset temperature of the release agent particles and lower than the softening temperature of the resin fine particles. The method for producing a capsule toner according to claim 4, wherein the toner base particles are agitated.   The method for producing a capsule toner according to any one of claims 2 to 5, wherein a softening temperature of the resin fine particles is lower than a melting point of the release agent particles.   The method for producing a capsule toner according to claim 1, wherein an average primary particle diameter of the inorganic fine particles is smaller than an average primary particle diameter of the resin fine particles. A capsule toner manufactured by the capsule toner manufacturing method according to claim 1,
Toner base particles containing a binder resin and a colorant;
A release agent layer made of a release agent formed on the surface of the toner base particles;
A capsule toner comprising: a resin coating layer formed on a surface of the release agent layer, in which inorganic fine particles are dispersed in a resin.   A two-component developer comprising the capsule toner according to claim 8.

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