JP2013182201A - Capsule toner and method of manufacturing capsule toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capsule toner which can suppress the occurrence of low temperature off set and high temperature off set and suppress decrease in fluidity in the case of agitation over a long time, and a method of manufacturing the same.SOLUTION: A capsule toner includes a toner base particle, and a resin coating layer provided on the surface of the toner base particle. The resin coating layer is formed of a large-diameter resin fine particle, and a small-diameter resin fine particle. The large-diameter resin fine particle is composed of a first amorphous resin. The small-diameter resin fine particle has a volume average particle diameter smaller than that of the large-diameter resin fine particle and composed of a second amorphous resin.

Description

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

  In an image forming apparatus using an electrophotographic system, an image is formed through, for example, charging, exposure, development, transfer, cleaning, static elimination, and fixing processes. In the charging process, the surface of the photoconductor to be rotated is uniformly charged by the charging device. In the exposure process, the charged photoconductor surface is irradiated with laser light by the exposure device, and an electrostatic latent image is formed on the surface of the photoconductor. Is done. Next, in the development process, the electrostatic latent image on the surface of the photoconductor is developed with a developer by a developing device to form a toner image on the surface of the photoconductor. In the transfer step, the toner image on the surface of the photoconductor is transferred by the transfer device. Transferred onto the transfer material. Thereafter, in the fixing step, the toner image is fixed on the transfer material by being heated by a fixing device. Further, the transfer residual toner remaining on the surface of the photoconductor after the image forming operation is removed by a cleaning device in a cleaning process and collected in a predetermined recovery unit, and the residual charge on the surface of the photoconductor after cleaning is removed in a static elimination process. In order to prepare for the next image formation, the charge is removed by the charge removal device.

  The developer used in such an image forming apparatus includes toner. As a method for improving the fluidity, transferability and chargeability of the toner, for example, a method in which the surface of the toner base particles is coated with a resin coating layer made of a resin having higher heat resistance than the toner base particles to form a capsule toner. is there. By covering the surface of the toner base particles with the resin coating layer, it is possible to suppress dissolution of low-melting-point components such as a release agent contained in the toner base particles, thereby improving the blocking resistance in the development process, The fluidity, transferability and chargeability of the toner are improved.

  However, the capsule toner generally does not easily dissolve the release agent contained in the toner base particles due to the resin coating layer in the fixing process, so that low temperature offset and high temperature offset are likely to occur, and a sufficiently wide non-offset. There is a problem that the area cannot be obtained.

  In order to solve such a problem, for example, Patent Document 1 discloses a capsule toner in which a resin coating layer containing a crystalline polyester resin and an amorphous resin is provided on the surface of toner base particles.

JP 2011-70152 A

  However, when the capsule toner disclosed in Patent Document 1 is produced by a pulverization method and is produced using toner mother particles having an irregular shape and a large number of irregularities, the capsule toner is stirred for a long time in a developing device. Local peeling of the resin coating layer occurs.

  In this way, the capsule toner in which the resin coating layer is locally peeled is deteriorated in fluidity, so that mixing of the capsule toner newly supplied to the developing device deteriorates, that is, already exists in the developing device. There is a problem that it takes time until the capsule toner newly supplied to the developing device is sufficiently mixed with the capsule toner. As a result, when the capsule toner is newly supplied to the developing device, the chargeability of the developer is lowered.

  An object of the present invention is to provide a capsule toner capable of suppressing the occurrence of a low temperature offset and a high temperature offset and suppressing a decrease in fluidity even when stirred for a long time, and a method for producing the same.

The present invention provides toner base particles containing a binder resin and a colorant;
A resin coating layer provided on the surface of a toner base particle, comprising a first amorphous resin fine particle made of a first amorphous resin and a second amorphous resin, which is more than the first amorphous resin fine particle. And a resin coating layer formed by forming a film of second amorphous resin fine particles having a small volume average particle diameter.

In the present invention, the volume average particle diameter d1 of the first amorphous resin fine particles is 500 nm or less, the volume average particle diameter d2 of the second amorphous resin fine particles is 20 nm or more,
The volume average particle diameter d1 of the first amorphous resin fine particles and the volume average particle diameter d2 of the second amorphous resin fine particles satisfy the following formula (1).
0.1 ≦ d2 / d1 ≦ 0.7 (1)

The present invention also provides a first amorphous resin fine particle made of the first amorphous resin and a second amorphous resin, the second amorphous resin having a volume average particle size smaller than that of the first amorphous resin fine particle. Mixed fine resin particles and toner base particles containing a binder resin and a colorant are mixed by stirring, and the first amorphous resin fine particles and the second amorphous resin fine particles are adhered to the surface of the toner base particles. An amorphous resin fine particle adhesion step for obtaining adhering toner base particles;
A spraying step of spraying a spray liquid, which is a liquid for plasticizing the toner base particles, the first amorphous resin fine particles, and the second amorphous resin fine particles, onto the mixed resin fine particle-attached toner base particles in a fluid state with stirring. When,
While spraying the spray liquid, stirring is continued until the first amorphous resin fine particles and the second amorphous resin fine particles contained in the mixed resin fine particle-adhered toner mother particles are softened to form a film. And a film forming step of forming a resin coating layer on the surface of the particles.

Further, in the present invention, the amorphous resin fine particle adhesion step includes
A mixed resin fine particle production step of stirring and mixing the first amorphous resin fine particles and the second amorphous resin fine particles to obtain mixed resin fine particles;
And a mixed resin fine particle adhering step in which the toner base particles and the mixed resin fine particles are agitated and mixed to attach the mixed resin fine particles to the surface of the toner mother particles to obtain mixed resin fine particle-attached toner mother particles.

According to the present invention, toner mother particles containing a binder resin and a colorant and first amorphous resin fine particles made of a first amorphous resin are stirred and mixed, and a first amorphous property is formed on the surface of the toner mother particles. A first amorphous resin fine particle attaching step of attaching resin fine particles to obtain first amorphous resin fine particle attached toner base particles;
The second amorphous resin fine particles, which are made of the second amorphous resin and have a volume average particle diameter smaller than the first amorphous resin fine particles, and the first amorphous resin fine particle-attached toner base particles are stirred and mixed. A second amorphous resin fine particle attachment step of obtaining second amorphous resin fine particle-attached toner mother particles by attaching second amorphous resin fine particles to the surface of the first amorphous resin fine particle-attached toner mother particles;
A spray liquid which is a liquid for plasticizing the toner base particles, the first amorphous resin fine particles, and the second amorphous resin fine particles is used as the second amorphous resin fine particle-attached toner base particles in a fluid state under stirring. A spraying process for spraying;
While spraying the spray liquid, stirring is continued until the first amorphous resin fine particles and the second amorphous resin fine particles contained in the second amorphous resin fine particle-adhered toner base particles are softened to form a film. And a film forming step of forming a resin coating layer on the surface of the toner base particles.

In the present invention, the volume average particle diameter d1 of the first amorphous resin fine particles is 500 nm or less, the volume average particle diameter d2 of the second amorphous resin fine particles is 20 nm or more,
The volume average particle diameter d1 of the first amorphous resin fine particles and the volume average particle diameter d2 of the second amorphous resin fine particles satisfy the following formula (1).
0.1 ≦ d2 / d1 ≦ 0.7 (1)

  According to the present invention, the capsule toner includes toner base particles containing a binder resin and a colorant, and a resin coating layer provided on the surface of the toner base particles. The resin coating layer is composed of a first amorphous resin fine particle made of a first amorphous resin and a second amorphous resin, and a second amorphous resin having a volume average particle size smaller than that of the first amorphous resin fine particle. It is formed by forming a fine resin fine particle into a film.

  The resin coating layer is formed by filming the first amorphous resin fine particles and the second amorphous resin fine particles having a volume average particle diameter smaller than that of the first amorphous resin fine particles. It is considered that the resin coating layer has a moderate and uniform degree of density.

  Since the degree of density of the resin coating layer is moderate and uniform throughout, the release agent contained in the toner base particles oozes out on the surface of the capsule toner in the fixing process, thereby suppressing the occurrence of low temperature offset and high temperature offset. can do. In addition, even if stirring is performed in the developing device for a long time, it is possible to prevent the resin coating layer from peeling off from the surface of the toner base particles, and thus it is possible to suppress a decrease in fluidity.

  According to the invention, the volume average particle diameter d1 of the first amorphous resin fine particles is 500 nm or less, and the volume average particle diameter d2 of the second amorphous resin fine particles is 20 nm or more. Further, the volume average particle diameter d1 of the first amorphous resin fine particles and the volume average particle diameter d2 of the second amorphous resin fine particles satisfy the above formula (1).

  The volume average particle diameter d1 of the first amorphous resin fine particles, the volume average particle diameter d2 of the second amorphous resin fine particles are in the above range, and the volume average particle diameter d1 of the first amorphous resin fine particles are 2 Since the volume average particle diameter d2 of the amorphous resin fine particles satisfies the above formula (1), the degree of density of the resin coating layer can be further optimized, so that the resin coating layer is peeled off in the development process. In addition, the occurrence of high temperature offset and low temperature offset due to insufficient release of the release agent in the fixing step can be suppressed. Therefore, a decrease in fluidity is further suppressed, and a capsule toner having a wide non-offset region and good fixability is obtained.

  According to the invention, the method for producing the capsule toner includes an amorphous resin fine particle attaching step, a spraying step, and a film forming step.

  In the amorphous resin fine particle attaching step, the first amorphous resin fine particle made of the first amorphous resin and the second amorphous resin are made, and the volume average particle diameter is smaller than that of the first amorphous resin fine particle. The second amorphous resin fine particles and the toner base particles containing the binder resin and the colorant are stirred and mixed to adhere the first amorphous resin fine particles and the second amorphous resin fine particles to the surface of the toner base particles. In this way, toner base particles having mixed resin fine particles are obtained.

  In the spraying step, a spray liquid that is a liquid for plasticizing the toner base particles, the first amorphous resin fine particles, and the second amorphous resin fine particles is applied to the mixed resin fine particle-attached toner base particles that are in a fluid state under stirring. Spray.

  In the film forming step, stirring is continued while spraying the spray liquid until the first amorphous resin fine particles and the second amorphous resin fine particles contained in the mixed resin fine particle-adhered toner base particles are softened to form a film. Then, a resin coating layer is formed on the surface of the toner base particles.

  By using the first amorphous resin fine particles and the second amorphous resin fine particles to form the resin coating layer, the first resin fine particles having a relatively large particle diameter are formed in the amorphous resin fine particle adhesion step. It enters into the recesses of the toner base particles. Therefore, in the film forming step, sufficient stress due to mechanical impact force can be applied to all the first amorphous resin fine particles and the second amorphous resin fine particles adhering to the surface of the toner base particles. A strong resin coating layer having a uniform density can be formed.

  Moreover, the density of the resin coating layer can be optimized by configuring the first amorphous resin fine particles and the second amorphous resin fine particles from the amorphous resin.

  According to the invention, the non-crystalline resin fine particle adhering step includes a mixed resin fine particle producing step of stirring and mixing the first non-crystalline resin fine particles and the second non-crystalline resin fine particles to obtain mixed resin fine particles, and a toner. A mixed resin fine particle adhesion step of stirring and mixing the mother particles and the mixed resin fine particles to adhere the mixed resin fine particles to the surface of the toner mother particles to obtain mixed resin fine particle-attached toner mother particles.

  As a result, the first resin fine particles having a relatively large particle diameter can enter the concave portions of the toner base particles in the mixed resin fine particle attaching step. Sufficient stress due to mechanical impact force can be applied to the first amorphous resin fine particles and the second amorphous resin fine particles, and a strong and uniform resin coating layer can be formed.

  According to the invention, the capsule toner manufacturing method includes a first amorphous resin fine particle attaching step, a second amorphous resin fine particle attaching step, a spraying step, and a film forming step.

  In the first amorphous resin fine particle adhering step, the toner base particles containing the binder resin and the colorant and the first amorphous resin fine particles made of the first amorphous resin are stirred and mixed to obtain a surface of the toner base particles. The first amorphous resin fine particles are adhered to the first amorphous resin fine particle-attached toner base particles.

  In the second amorphous resin fine particle attaching step, the second amorphous resin fine particles made of the second amorphous resin and having a volume average particle diameter smaller than that of the first amorphous resin fine particles, and the first amorphous resin The toner base particles with fine particle adhesion are agitated and mixed, and the second amorphous resin fine particles are adhered to the surface of the first amorphous resin fine particle adhesion toner mother particles to obtain second amorphous resin fine particle adhesion toner mother particles.

  In the spraying step, a spray liquid that is a liquid for plasticizing the toner base particles, the first amorphous resin fine particles, and the second amorphous resin fine particles is used as the second amorphous resin fine particle-attached toner that is in a fluid state under stirring. Spray onto mother particles.

  In the film forming step, stirring is performed while spraying the spray liquid until the first amorphous resin fine particles and the second amorphous resin fine particles contained in the second amorphous resin fine particle-attached toner base particles are softened and formed into a film. The resin coating layer is formed on the surface of the toner base particles.

  The first amorphous resin fine particles having a relatively large particle diameter are attached to the surface of the toner base particles in advance, whereby the first amorphous resin fine particles are selectively attached to the concave portions of the toner base particles, It can suppress adhering.

  Therefore, in the film forming step, sufficient stress due to mechanical impact force can be applied to all the first amorphous resin fine particles and the second amorphous resin fine particles adhering to the surface of the toner base particles, and the resin coating layer A stronger resin coating layer having a moderate and uniform degree of density can be formed.

  According to the invention, the volume average particle diameter d1 of the first amorphous resin fine particles is 500 nm or less, and the volume average particle diameter d2 of the second amorphous resin fine particles is 20 nm or more. The volume average particle diameter d1 of the first amorphous resin fine particles and the volume average particle diameter d2 of the second amorphous resin fine particles satisfy the above formula (1).

  The volume average particle diameter d1 of the first amorphous resin fine particles, the volume average particle diameter d2 of the second amorphous resin fine particles are in the above range, and the volume average particle diameter d1 of the first amorphous resin fine particles are When the volume average particle diameter d2 of the two amorphous resin fine particles satisfies the above formula (1), a resin coating layer with a more appropriate degree of density can be formed. Accordingly, it is possible to obtain a capsule toner that can further suppress a decrease in fluidity and suppress the occurrence of a low temperature offset and a high temperature offset.

It is process drawing which shows the manufacturing method of the capsule toner which is 1st Embodiment. FIG. 3 is a front view illustrating a configuration of a toner manufacturing apparatus 201 used for manufacturing capsule toner. FIG. 3 is a cross-sectional view of the toner manufacturing apparatus 201 shown in FIG. 2 cut along a cutting plane line A200-A200. FIG. 3 is a front view showing a configuration around a powder charging unit 206 and a powder recovery unit 207. It is process drawing which shows the manufacturing method of the capsule toner which is 2nd Embodiment.

1. Capsule Toner A capsule toner according to an embodiment of the present invention includes toner base particles and a resin coating layer provided on the surface of the toner base particles. The toner base particles include a binder resin, a colorant, and a release agent.

  The resin coating layer is formed from large particle size resin particles that are first amorphous resin particles and small particle size resin particles that are second amorphous resin particles. The large particle size resin fine particles are made of the first amorphous resin. The small particle size resin fine particles have a volume average particle size smaller than that of the large particle size resin fine particles and are made of the second amorphous resin.

  By forming the resin coating layer from the large particle size resin fine particles composed of the first amorphous resin and the small particle size resin fine particles composed of the second amorphous resin fine particle, the degree of density is moderate throughout, and It is considered that a uniform resin coating layer can be obtained.

  As the density of the resin coating layer increases, the voids inside the resin coating layer decrease, and as the density decreases, the voids inside the resin coating layer increase. When the degree of density is moderate, the inside of the resin coating layer does not mean that the large particle size resin particles and the small particle size resin particles are completely adhered over the entire surface, but a certain amount between these particles. It shows that a void is formed.

  When the density of the resin coating layer is moderate and uniform throughout, the release agent contained in the toner base particles oozes out on the surface of the capsule toner during fixing, thus suppressing the occurrence of low temperature offset and high temperature offset. can do. In addition, even if stirring is performed in the developing device for a long time, it is possible to prevent the resin coating layer from peeling off from the surface of the toner base particles, and thus it is possible to suppress a decrease in fluidity.

Hereinafter, the configuration of the capsule toner of the present invention will be described in detail.
(Toner mother particles)
The toner base particles include a binder resin, a colorant, and a release agent.

  The binder resin is not particularly limited, and a known binder resin can be used. For example, polystyrene, styrene resin such as styrene-acrylic acid ester copolymer resin, acrylic resin such as polymethyl methacrylate, polyethylene, and the like. And polyolefin resins such as polyester, polyurethane, and epoxy resin. Moreover, you may use resin obtained by mixing the mold release agent mentioned later with a raw material monomer mixture, and performing a polymerization reaction. Binder resin can be used individually by 1 type, or can use 2 or more types together.

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

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

  As the polyhydric alcohol, those known as monomers for polyesters can be used. For example, aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, hexanediol, neopentylglycol, glycerin, cyclohexanediol, cyclohexanediene, etc. Examples thereof include aromatic diols such as alicyclic polyhydric alcohols such as methanol and hydrogenated bisphenol A, ethylene oxide adducts of bisphenol A, and propylene oxide adducts of bisphenol A. A polyhydric alcohol can be used individually by 1 type, or can use 2 or more types together.

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

  When a methyl esterified product of a polybasic acid is used as a part of the polybasic acid, a demethanol polycondensation reaction occurs. In this polycondensation reaction, for example, the carboxyl group content at the end of the polyester can be adjusted by appropriately changing the blending ratio of polybasic acid and polyhydric alcohol, the reaction rate, etc., and thus the properties of the resulting polyester are changed. be able to. When trimellitic anhydride is used as the polybasic acid, a carboxyl group can be easily introduced into the main chain of the polyester, and a modified polyester is obtained. It is also possible to obtain a self-dispersible polyester in water by bonding hydrophilic groups such as carboxyl groups and sulfonic acid groups to the main chain and / or side chains of the polyester. Further, polyester and acrylic resin may be grafted.

  The glass transition point of the binder resin is preferably 30 ° C. or higher and 80 ° C. or lower. When the glass transition point of the binder resin is less than 30 ° C., it is easy to generate blocking in which the capsule toner particles are thermally aggregated inside the image forming apparatus, which may reduce storage stability. When the glass transition point of the binder resin exceeds 80 ° C., the fixability of the capsule toner to the recording medium is lowered, and there is a possibility that fixing failure occurs.

The softening temperature of the binder resin is preferably 90 ° C. or higher and 150 ° C. or lower.
As the colorant, organic dyes, organic pigments, inorganic dyes, inorganic pigments and the like commonly used in the electrophotographic field can be used.

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

  Examples of the yellow colorant include chrome lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, and navel yellow.

  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 the red colorant include bengara, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, risol red, pyrazolone red, and watching red.

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

  Examples of the blue colorant include bitumen, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, and phthalocyanine blue partially chlorinated products.

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

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

  One colorant can be used alone, or two or more different colorants can be used in combination. Moreover, even if it is the same color, 2 or more types can be used together. The amount of the colorant to be used is not particularly limited, but is preferably from 0.1 to 20 parts by weight, more preferably from 0.2 to 10 parts by weight, based on 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.

  Examples of mold release agents include carnauba wax and derivatives thereof, paraffin wax and derivatives thereof, petroleum wax such as microcrystalline wax and derivatives thereof, Fischer-Tropsch wax and derivatives thereof, and polyolefin wax (polyethylene wax, polypropylene wax, etc.) And hydrocarbon derivatives such as low molecular weight polypropylin wax and derivatives thereof, polyolefin polymer waxes (low molecular weight polyethylene wax and the like) and derivatives thereof, and the like. Derivatives include oxides, block copolymers of vinyl monomers and waxes, graft modified products of vinyl monomers and waxes, and the like.

  The amount of the release agent used is not particularly limited and can be appropriately selected from a wide range, but is preferably 0.2 parts by weight or more and 20 parts by weight or less, and 0.5 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the binder resin. The following is more preferable, and 1.0 to 8.0 parts by weight is further preferable.

  The toner base particles may contain a charge control agent as required 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 controlling positive charge include nigrosine dyes, basic dyes, quaternary ammonium salts, quaternary phosphonium salts, aminopyrines, pyrimidine compounds, polynuclear polyamino compounds, aminosilanes, nigrosine dyes and derivatives thereof, and triphenylmethane. Derivatives, guanidine salts, amidine salts and the like can be mentioned.

  Charge control agents for controlling negative charges include oil-soluble dyes such as oil black and spiron black, metal-containing azo compounds, azo complex dyes, metal salts of naphthenic acid, metal salts of salicylic acid and its derivatives (metals are metal Chromium, zinc, zirconium, etc.), organic bentonite compounds, boron compounds, fatty acid soaps, long-chain alkyl carboxylates, resin acid soaps, and the like.

  A charge control agent can be used individually by 1 type, or can use 2 or more types together as needed. The amount of the charge control agent used is not particularly limited and can be appropriately selected from a wide range, but is preferably 0.5 parts by weight or more and 3 parts by weight or less with respect to 100 parts by weight of the binder resin.

The volume average particle size 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.
The coefficient of variation of the toner base particles is preferably 10% or more and 30% or less.

  The shape factor SF2 of the toner base particles is preferably 120 or more and 160 or less. The shape factor SF2 indicates the degree of unevenness of the particles.

(Resin coating layer)
The resin coating layer is formed by forming a large particle size fine particle made of the first amorphous resin and a small particle size resin fine particle made of the second amorphous resin.

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

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

The degree of crystallization can be adjusted by the type and ratio of the raw material monomers and the production conditions (for example, reaction temperature, reaction time, cooling rate, etc.).

  As the first amorphous resin and the second amorphous resin, for example, styrene resin such as polystyrene resin, styrene acrylic copolymer resin, acrylic resin such as polymethyl methacrylate, polyolefin resin such as polyethylene, polyester, Examples thereof include polyurethane and epoxy resin.

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

  A publicly known thing can be used as an acrylic monomer of styrene acrylic copolymer resin, For example, acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, etc. which may have a substituent are mentioned. Specific examples of the acrylic monomer include, for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate, and acrylic acid. Acrylic acid ester monomers such as 2-ethylhexyl, n-octyl acrylate, decyl acrylate, dodecyl acrylate, methyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate , Methacrylate monomers such as n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, decyl methacrylate, dodecyl methacrylate, hydroxyethyl acrylate, hydroxy methacrylate Pills and the like hydroxyl group-containing (meth) acrylic acid ester monomers such as. An acrylic monomer can be used individually by 1 type, or can use 2 or more types together.

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

  It is preferable that the first amorphous resin and the second amorphous resin contain the same monomer component. By including the same monomer component, the resin coating layer can be made more uniform over the entire surface, so that the resin coating layer can be further prevented from peeling from the toner base particles.

  The glass transition point of the first amorphous resin and the second amorphous resin is preferably 50 ° C. or higher and 80 ° C. or lower.

  The softening point of the first amorphous resin and the second amorphous resin is preferably 100 ° C. or higher and 140 ° C. or lower.

  The first amorphous resin and the second amorphous resin preferably have the same glass transition point and softening point.

  The volume average particle diameter d1 of the large particle diameter resin fine particles is preferably 80 nm or more and 500 nm or less, and the volume average particle diameter d2 of the small particle diameter resin fine particles is preferably 20 nm or more and 400 nm or less.

Moreover, it is preferable that the volume average particle diameter d1 of the large particle resin fine particles and the volume average particle diameter d2 of the second amorphous resin fine particles satisfy the following formula (1).
0.1 ≦ d2 / d1 ≦ 0.7 (1)

  The volume average particle diameter d1 of the large particle size resin fine particles and the volume average particle size d2 of the small particle size resin fine particles are within the above ranges, and the volume average particle size d1 of the large particle size resin fine particles and the volume of the small particle size resin fine particles Since the degree of density of the resin coating layer can be made more appropriate when the ratio to the average particle diameter d2 satisfies the above formula (1), it is possible to further suppress the peeling of the resin coating layer in the development process. In addition, it is possible to suppress the occurrence of high temperature offset and low temperature offset due to insufficient release of the release agent in the fixing step. Therefore, a decrease in fluidity is further suppressed, and a capsule toner having a wide non-offset region and good fixability is obtained.

  The coefficient of variation of the large particle size resin fine particles is preferably from 10 to 50, and the coefficient of variation of the small particle size resin fine particles is preferably from 5 to 40.

2. Method for Producing Capsule Toner Hereinafter, a method for producing a capsule toner with an appropriate degree of density of the resin coating layer as described above will be described. The capsule toner manufacturing method according to an embodiment of the present invention includes a first embodiment and a second embodiment.

(First embodiment)
FIG. 1 is a process diagram showing a capsule toner manufacturing method according to the first embodiment. The capsule toner manufacturing method of this embodiment includes a toner base particle preparation step S1 for preparing toner base particles, an amorphous resin fine particle preparation step S2 for obtaining dried resin fine particles, and the resin fine particles are attached to the toner base particles. Amorphous resin fine particle adhering step S3 to be performed, and a film forming step S4 for forming a resin coating layer on the surface of the toner base particles.

(1) Toner mother particle production step S1
In the toner base particle preparation step S1, toner base particles are prepared. In this embodiment, the toner base particles are produced by a pulverization method. Hereinafter, a method for producing toner base particles by a kneading and pulverizing method will be described.

  In preparation of toner base particles by a pulverization method, a toner base material containing a binder resin, a colorant and other additives is dry-mixed with a mixer and then melt-kneaded with a kneader to obtain a melt-kneaded product. . The melt-kneaded product is cooled and solidified, and the solidified product is pulverized with a pulverizer to obtain a finely pulverized product. Thereafter, toner base particles are obtained by adjusting the particle size such as classification as required.

  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. Examples include a Henschel type mixing apparatus, Ong mill (trade name, manufactured by Hosokawa Micron Corporation), hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.), and Cosmo system (trade name, manufactured by Kawasaki Heavy Industries, Ltd.).

  As the kneader, a known one can be used. For example, a general kneader such as a twin screw extruder, a three-roller, a lab blast mill can be used. 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. Examples thereof include open roll type kneaders such as Extruder and Needex (trade name, manufactured by Mitsui Mining Co., Ltd.).

  As a pulverizer, for example, a jet-type pulverizer that uses a supersonic jet stream, and a solidified material is introduced into a space formed between a rotor (rotor) and a stator (liner) that rotate at high speed. And an impact type pulverizer for pulverization.

  As the classification, a known classifier capable of removing toner mother particles excessively pulverized by centrifugal force and wind classification can be used, and examples thereof include a swirling wind classifier (rotary wind classifier). .

(2) Amorphous resin fine particle preparation step S2
In the amorphous resin fine particle preparation step S2, large particle resin fine particles and small particle resin fine particles are prepared. Hereinafter, the large particle size resin fine particles and the small particle size resin fine particles may be collectively referred to as amorphous resin fine particles. Amorphous resin fine particles are made into fine particles by, for example, dispersing the first amorphous resin and the second amorphous resin, which are raw materials of the amorphous resin fine particles, in a dispersion medium, and then emulsifying and dispersing them with a homogenizer or the like. Obtained. It can also be obtained by polymerizing the monomer components of the first amorphous resin and the second amorphous resin in a dispersion medium.

  The state in which the first amorphous resin and the second amorphous resin are emulsified and dispersed with a homogenizer, and the state in which the monomer components of the first amorphous resin and the second amorphous resin are polymerized are as follows. The crystalline resin fine particles are dispersed in the dispersion medium, and the amorphous resin fine particles are dispersed in the dispersion medium. It is necessary to take out only the fine resin particles. As the dispersion medium, a solvent that disperses the amorphous resin fine particles without dissolving them is used, and water is an example.

  The amorphous resin fine particles obtained in this manner are preferably dried. Any method may be used to dry the amorphous resin fine particles. For example, the amorphous resin fine particles are dried by a method such as hot air heat receiving drying, conduction heat transfer drying, far infrared drying, or microwave drying.

(3) Amorphous resin fine particle adhesion step S3
In the amorphous resin fine particle attaching step S3, the large particle size resin fine particles and the small particle size resin fine particles are adhered to the surface of the toner base particles. The amorphous resin fine particle adhesion step S3 includes a mixed resin fine particle production step S3a and a mixed resin fine particle adhesion step S3b.

(3) -1, mixed resin fine particle production step S3a
In the mixed resin fine particle production step S3a, the large particle size resin fine particles and the small particle size resin fine particles prepared in the amorphous resin fine particle preparation step S2 are mixed with a mixer to obtain mixed resin fine particles.

  Henschel type mixers 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.), ong mill (Trade name, manufactured by Hosokawa Micron Corporation), hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.), Cosmo system (trade name, manufactured by Kawasaki Heavy Industries, Ltd.), and the like.

  The operating conditions of the apparatus are preferably set as appropriate depending on the material of the amorphous resin fine particles, the type of apparatus, etc. For example, the peripheral speed of the stirring blade of the mixer is preferably 20 m / s or more and 60 m / s or less.

  The ratio of the addition amount of the large particle size resin fine particles and the addition amount of the small particle size resin fine particles is preferably 8: 2 to 2: 8.

(3) -2, mixed resin fine particle adhesion step S3b
In the mixed resin fine particle adhering step S3b, the mixed resin fine particles and the toner base particles are agitated and mixed to adhere the mixed resin fine particles to the surface of the toner base particles to obtain mixed resin fine particle-attached toner base particles.

  As an apparatus for stirring and mixing the mixed resin fine particles and the toner base particles, the same mixer as that used in the mixed resin fine particle production step S3a can be used.

  By stirring and mixing with a mixer, impact force is applied to the mixed resin fine particles, and the amorphous resin fine particles are crushed to primary particles, so that the mixed resin fine particles uniformly adhere to the surface of the toner base particles ( Immobilization).

  The addition amount of the mixed resin fine particles is not particularly limited, but is preferably 1 part by weight or more and 30 parts by weight or less with respect to 100 parts by weight of the toner base particles because the entire surface of the toner base particles needs to be coated. When the mixed resin fine particles are used at such a ratio, the mixed resin fine particles can be adhered to the entire surface of the toner base particles, and a resin coating layer can be formed on the entire surface of the toner base particles. As a result, it is possible to more reliably prevent the aggregation of the capsule toner that occurs due to the release of the release agent contained in the toner base particles in the development step.

  If the amount of the mixed resin fine particles is less than 1 part by weight, the entire surface of the toner base particles cannot be coated, and the release agent contained in the toner base particles may ooze out in the development process. If the addition amount of the mixed resin fine particles exceeds 30 parts by weight, the film thickness of the resin coating layer becomes too large, and depending on the constituent material of the mixed resin fine particles, the fixability of the capsule toner may be lowered.

(4) Film forming step S4
In the film forming step S4, a resin coating layer is formed on the surface of the toner base particles. First, a toner manufacturing apparatus 201 used in this process will be described with reference to FIGS.

<Toner production device>
FIG. 2 is a front view showing a configuration of a toner manufacturing apparatus 201 used for manufacturing capsule toner. FIG. 3 is a cross-sectional view of the toner manufacturing apparatus 201 shown in FIG. 2 cut along a cutting plane line A200-A200.

  The toner manufacturing apparatus 201 is a rotary stirring device, and includes a powder flow path 202, a spraying means 203, a rotary stirring means 204, a temperature adjustment jacket (not shown), a powder input unit 206, and a powder recovery unit 207. It is comprised including.

(Powder channel)
The powder channel 202 includes a stirring unit 208 and a powder flow unit 209. The stirring unit 208 is a cylindrical container-like member having an internal space. Openings 210 and 211 are formed in the stirring unit 208 which is a rotary stirring chamber.

  The opening 210 is formed so as to penetrate the end wall 208a in the thickness direction at a substantially central portion of one end wall 208a in the axial direction of the stirring unit 208. The opening 211 is formed to open above the peripheral wall 208b perpendicular to the end wall 208a.

  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, mixed resin fine particle-attached toner base particles and gas flow. The powder flow path 202 is provided so that the powder flow direction 214, which is the direction in which the mixed resin fine particle-attached toner base particles flow, is constant.

  It should be noted that the temperature in the powder flow path 202 becomes substantially uniform at any part due to the flow of the mixed resin fine particle-attached toner base particles.

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

(Spraying means)
The spray means 203 is provided so as to be inserted into an opening formed in the outer wall of the powder flow path 202, and is closest to the opening 211 in the flow direction 214 of the mixed resin fine particle-attached toner base particles in the powder flow portion 209. On the upstream side.

  The spray means 203 includes a liquid storage section for storing a spray liquid (not shown), a carrier gas supply section for supplying a carrier gas (not shown), and a mixture obtained by mixing the spray liquid and the carrier gas in the powder flow path 202. A two-fluid nozzle 203a that sprays toward the mixed resin fine particle-attached toner base particles and sprays droplets of the spray liquid onto the mixed resin fine particle-attached toner base particles, and a spray amount control means (not shown).

  As the spray liquid, water and a polar organic solvent having an effect of plasticizing without dissolving the toner base particles and the amorphous resin fine particles are used. Although it does not specifically limit as a polar organic solvent, Organic solvents, such as a lower alcohol and acetonitrile, are mentioned.

  The viscosity of the spray liquid is preferably 5 cP or less. Here, the “viscosity of the liquid” means, for example, a viscosity measured at 25 ° C. using a cone plate type rotary viscometer.

  Examples of the volatile liquid having a viscosity of 5 cP or lower include lower alcohols. Since the lower alcohol has a low viscosity and easily evaporates, the sprayed droplets do not become coarse, and a volatile liquid having a uniform and fine droplet diameter can be sprayed. Further, at the time of collision between the mixed resin fine particle-adhered toner base particles and the volatile liquid droplets, the miniaturization of the droplets can be further promoted. As a result, the surface of the mixed resin fine particle-attached toner base particles is uniformly wetted and blended, and the mixed resin fine particle-attached toner base particles are softened by a synergistic effect with the collision energy, and as a result, a capsule toner having excellent uniformity is obtained. be able to.

  Further, the lower alcohol has high wettability with respect to the toner base particles of the mixed resin fine particle-adhered toner base particles, and makes it easy to form a resin coating layer on the entire surface or most of the toner base particles. Further, the mixed resin fine particle-adhered toner base particles plasticized with the lower alcohol are deformed by an external force to form a uniform resin coating layer on the surface of the toner base particles. Further, the lower alcohol is easy to dry, the drying time for removing the volatile liquid after the resin coating layer is formed can be shortened, and aggregation of the obtained capsule toners can be suppressed.

  Examples of the lower alcohol include methanol, ethanol, propanol, butanol and the like, and ethanol is particularly preferable among these.

  The carrier gas supply unit is provided with a float-type flow meter (not shown), and the supply amount of the carrier gas can be measured. Compressed air or the like can be used as the carrier gas. The two-fluid nozzle 203a includes a liquid pipe and an air pipe, and has a structure in which a part of the two pipes is connected and the center is not displaced. The two-fluid nozzle 203 a sprays the spray liquid at a constant speed, and the concentration of the spray liquid is kept constant in the powder flow path 202.

  The angle (spray angle) θ between the liquid spray direction in which the spray means 203 sprays the spray liquid and the powder flow direction 214 is set so that the spray liquid is sprayed uniformly on the surface of the mixed resin fine particle-attached toner base particles. The spray angle θ is, for example, preferably 0 to 45 °, and more preferably 0 ° (parallel). Φ in FIG. 3 indicates the spread angle of the spray liquid.

  Due to the synergistic effect of the circulating means and the temperature adjusting means described later, the amorphous resin fine particles can be plasticized to obtain a capsule toner having a uniform film thickness and particle size.

(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 temperature below the glass transition point of the binder resin contained in the toner base particles.

  Thus, in the film forming step S4c, it is possible to prevent adhesion of the mixed resin fine particle-adhered toner base particles due to the temperature in the powder channel 202 being too high, and the temperature in the powder channel 202 is It is too low, and it is possible to prevent the spray liquid from staying inside the powder flow path 202 without being gasified.

  The temperature adjusting jacket is preferably provided on the wall surface of the powder flow path 202 where the mixed resin fine particle-adhered toner base particles are likely to adhere. For example, the powder from the spray means 203 on the inner wall of the powder flow section 209 It is provided at a portion downstream of the flow direction 214.

  Further, the temperature adjusting jacket is provided in the vicinity of the opening 210 on the wall surface of the stirring unit 208. By providing such a temperature adjustment jacket, the mixed resin fine particle-attached toner mother particles flowing into the stirring unit 208 from the opening 210 and the mixed resin fine particle-attached toner mother particles flowing in the stirring unit 208 are collided. Adhesion of the mixed resin fine particle adhering toner base particles to the vicinity of the opening 210 can be prevented.

  Furthermore, it is more preferable that the temperature adjusting jacket is provided on the entire wall surface of the powder flow section 209 and the entire wall surface of the stirring section 208. By providing such a temperature adjustment jacket, it is possible to more reliably prevent the mixed resin fine particle adhering toner base particles from adhering to the inner wall surface of the powder flow path 202.

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

  The powder input unit 206 includes a supply pipe 212 that communicates a hopper (not shown) that supplies mixed resin fine particle-adhered toner base particles and a powder flow path 202, and an electromagnetic valve 213 provided in the supply pipe 212.

  The mixed resin fine particle adhering 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 mixed resin fine particle-attached toner mother particles supplied to the powder flow path 202 flow in a constant powder flow direction 214 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 mixed resin fine 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 particles flowing through the powder flow path 202 are collected in the collection tank 215 through the collection pipe 216. In addition, when the flow path in the collection pipe 216 is closed by the electromagnetic valve 217, the capsule toner particles flowing through the powder flow path 202 are not collected.

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

  The film forming step S4 using the toner manufacturing apparatus 201 includes a temperature adjusting step S4a, a spraying step S4b, a film forming step S4c, and a recovery step S4d.

(4) -1, temperature adjustment step S4a
In the temperature adjustment step S4a, while rotating the rotary stirring means 204, by passing a refrigerant or a temperature medium through the space inside the temperature adjustment jacket disposed inside the powder flow path 202 and outside the rotary stirring means 204, The temperature in the powder flow path 202 and the rotary stirring means 204 are adjusted to a temperature below the glass transition point of the binder resin. This temperature is maintained throughout the film forming step S4. As a result, the temperature in the powder flow path 202 can be controlled to be equal to or lower than the temperature at which the mixed resin fine particle-attached toner base particles introduced in the spraying step S4b described later are not softened and deformed.

(4) -2, spraying step S4b
In the spraying step S4b, the mixed resin fine particle-adhered toner base particles are introduced from the powder introduction unit 206 into the powder flow path 202 in a state where the rotary shaft member 218 of the rotary stirring unit 204 is rotating, and then the toner base particles. The spray liquid, which is a liquid that has an effect of plasticizing without dissolving the amorphous resin fine particles, is sprayed onto the mixed resin fine particle-attached toner base particles in a fluid state.

  In spraying the spray liquid, the mixed resin fine particle-attached toner base particles are flowed from 1.0 to 10 minutes after the mixed resin fine particle-attached toner base particles are supplied from the powder input unit 206 to the powder flow path 202. The process starts after the flow rate of the mixed resin fine particle-attached toner base particles in the powder flow path 202 is stabilized.

  By starting the spraying after the flow rate of the mixed resin fine particle-attached toner base particles in the powder flow path 202 is stabilized, the spray liquid can be uniformly sprayed on the mixed resin fine particle-attached toner base particles, and the resin coating layer is uniform. The yield of capsule toner can be increased. At this time, the spray amount of the spray liquid is preferably 0.2 to 2 ml / min.

  The spray liquid is sent to the spraying means 203 at a constant flow rate by a liquid feed pump, and sprayed by the carrier gas from the spraying means 203. The sprayed sprayed liquid is gasified, and the gasified sprayed liquid spreads on the surface of the mixed resin fine particle-attached toner base particles. As a result, the toner base particles and the amorphous resin fine particles are plasticized.

  The spray liquid is preferably gasified so that the gas concentration in the powder flow path 202 is constant, and the gasified liquid is preferably discharged out of the powder flow path 202 through the gas discharge port 221b. By keeping the concentration of the gasified liquid constant, the drying speed of the spray liquid can be increased as compared with the case where the concentration is not kept constant. For this reason, it is possible to prevent the mixed resin fine particle-attached toner mother particles remaining in the undried spray liquid from sticking to each other, and to suppress the aggregation of the mixed resin fine particle-attached toner mother particles. As a result, the yield of capsule toner having a uniform resin coating layer can be further improved.

  It is preferable that the concentration of the gasified spray liquid in the powder passage 202 measured by the concentration sensor in the gas discharge unit 222 is about 3 vol% or less. When the concentration of the spray liquid is about 3 vol% or less, the drying speed of the spray liquid can be sufficiently increased, so that the mixed resin fine particle-adhered toner mother particles remaining in the undried spray liquid are prevented from adhering to each other, Aggregation of mixed resin fine particle-attached toner base particles can be suppressed.

Further, the concentration of the gasified spray liquid is more preferably 0.1 vol% or more and 3.0 vol% or less. When the concentration of the spray liquid is within such a range, aggregation of the mixed resin fine particle-adhered toner base particles can be prevented without reducing productivity.
The time for the spraying step S4b is preferably 2.0 minutes or more and 40 minutes or less.

(4) -3, film forming step S4c
In the film-forming step S4c, while the spray liquid is sprayed, the stirring of the rotary stirring means 204 is continued until the amorphous resin fine particles contained in the mixed resin fine-particle-attached toner base particles are softened and formed into a film, whereby the toner base particles A resin coating layer is formed on the surface.

  The film forming step S4c starts simultaneously with the spraying step S4b and ends simultaneously. In this case, the time of the film forming step S4c is the same as that of the spraying step S4b, and is preferably 2.0 minutes or longer and 40 minutes or shorter.

  Further, the film forming step S4c may be started at the same time as the spraying step S4b and may be ended after the spraying step S4b. In this case, the time for the film forming step S4c is preferably 3.0 minutes or more and 60 minutes or less.

  In the film forming step S4c, the mixed resin fine particle-adhered toner base particles are stirred and mixed for the time in the above range, whereby the amorphous resin fine particles can be appropriately formed on the surface of the toner base particles.

  In the spraying step S4b and the film forming step S4c, the peripheral speed of the outermost periphery of the rotary stirring means 204 is preferably 30 m / sec or more, and more preferably 50 m / sec or more and 120 m / sec or less. Thereby, sufficient mechanical impact force can be applied to the mixed resin fine particle-adhered toner base particles, and uniform and strong resin fine particles can be formed. If the peripheral speed of the outermost periphery of the rotary stirring means 204 is less than 30 m / sec, the mixed resin fine particle-attached toner base particles cannot be isolated and flowed in the powder flow path 202, and the surface of the toner base particles is uniform. There is a possibility that the resin coating layer cannot be formed.

(4) -4, Recovery step S4d
In the collection step S4d, the capsule toner particles, which are toner base particles having a resin coating layer formed on the surface, are discharged out of the apparatus from the powder collection unit 207 and collected.

  As described above, in the capsule toner manufacturing method of the present embodiment, the large resin particle and the small resin particle are used to form the resin coating layer. Therefore, in the mixed resin particle adhesion step S3b, Large particle size resin fine particles enter the recesses of the toner base particles. Therefore, in the film forming step S4, sufficient stress due to mechanical impact force can be applied to all the mixed resin fine particles adhering to the surface of the toner base particles, so that a uniform and strong resin coating layer is formed. be able to.

  If only the amorphous resin fine particles having a small particle diameter enter the concave portions of the toner base particles, the mechanical impact force is mainly applied to the amorphous resin fine particles adhering to the convex portions of the toner base particles. The amorphous resin fine particles attached to the concave portions of the toner base particles cannot be given sufficient stress due to mechanical impact force. For this reason, the degree of density of the resin coating layer is reduced in the recesses of the toner base particles, and a uniform and strong resin coating layer cannot be formed. There is a risk of peeling locally.

  Also, when the resin coating layer is formed using only amorphous resin fine particles having a large particle diameter, mechanical impact force is applied only to the amorphous resin fine particles adhering to the convex portions of the toner base particles. In addition, since the degree of density of the resin coating layer formed in the concave portions of the toner base particles is reduced, a uniform and strong resin coating layer cannot be formed.

  Moreover, the density of the resin coating layer can be moderated by forming the large particle size resin particles and the small particle size resin particles from the amorphous resin. If the large particle size resin fine particles and the small particle size resin fine particles are made of a crystalline resin, the large particle size resin fine particles and the small particle size resin fine particles are melted when the resin coating layer is formed. There is a possibility that the degree of sparse / dense cannot be made suitable. For this reason, in this embodiment, it is most preferable that the resin coating layer is formed only from amorphous resin fine particles.

  Furthermore, in the method for producing a capsule toner of the present embodiment, the amorphous resin fine particles are produced more than the conventional method for producing a capsule toner, in which a liquid in which resin fine particles are dispersed is sprayed on the toner base particles to form a resin coating layer. Since the shape remains on the toner surface, it has excellent cleaning properties.

(Second Embodiment)
FIG. 5 is a process diagram showing a capsule toner manufacturing method according to the second embodiment. The capsule toner manufacturing method of this embodiment includes a toner base particle preparation step S11 for preparing toner base particles, an amorphous resin fine particle preparation step S12 for obtaining dried amorphous resin fine particles, and a toner base particle. Large particle size resin fine particle adhesion step S13 for obtaining toner particle particles with large particle size resin fine particles by adhering particle size resin fine particles, and small particle size resin particles with small particle size resin fine particles adhered to the large particle size resin fine particle adhering toner base particles A small particle size resin fine particle adhesion step S14 for obtaining toner particle particles having a diameter resin fine particle adhesion, and a film forming step S15 for forming a resin coating layer on the surface of the toner mother particle.

(1) Toner mother particle production step S11
The toner base particle preparation step S11 is the same as the toner base particle preparation step S1 described above.

(2) Amorphous resin fine particle preparation step S12
The amorphous resin fine particle preparation step S12 is the same as the above-mentioned amorphous resin fine particle preparation step S2.

(3) Large particle size resin fine particle adhesion step S13
In the large particle size resin fine particle adhering step S13, the toner base particles and the dried large particle size resin fine particles are mixed using a mixer, and the large particle size resin fine particles are adhered to the surface of the toner mother particles. Resin fine particle-attached toner base particles are obtained.

  As the mixer, the mixer used in the mixed resin fine particle manufacturing step S3a described above can be used.

  The addition amount of the large particle size resin fine particles is preferably 0.4 parts by weight or more and 12 parts by weight or less with respect to 100 parts by weight of the toner base particles.

By agitating the toner base particles and the large particle size resin fine particles charged in the mixer, the large particle size resin fine particles are crushed to a submicron level that is about 1 to 10 times the primary particle size. The toner base particles uniformly adhere to the surface of the toner base particles, and toner base particles with large particle size resin fine particles are obtained.
At this time, the large particle size resin fine particles selectively adhere to the concave portions of the toner base particles.

The peripheral speed of the stirring blade of the mixer is preferably 20 m / s or more and 60 m / s or less.
The time of the large particle size resin fine particle attaching step S13 is preferably 2 minutes or more and 10 minutes or less.

(4) Small particle size resin fine particle adhesion step S14
In the small particle size resin fine particle adhering step S14, the small particle size resin fine particles are put into a mixer in which the large particle size resin fine particle adhered toner base particles are stirred, and small particles are formed on the surface of the large particle size resin fine particle adhered toner base particles. Small-sized resin fine particle-attached toner base particles are obtained by adhering small-diameter resin fine particles.

  The addition amount of the small particle size resin fine particles is preferably 0.4 parts by weight or more and 12 parts by weight or less with respect to 100 parts by weight of the toner base particles.

The small particle size resin fine particles charged into the mixer are agitated to be crushed to a submicron level, which is about 1 to 10 times the primary particle size. It adheres uniformly to the surface. Since the large particle size resin fine particles are attached to the recesses of the toner base particles, the small particle size resin fine particles are attached to other portions of the toner base particles.
The peripheral speed of the stirring blade of the mixer is preferably 20 m / s or more and 60 m / s or less.

  The toner base particles with small particle size resin fine particles are discharged out of the mixer and collected in a polyethylene storage bag or the like.

(5) Film forming step S15
The film forming step S15 includes a temperature adjusting step S15a, a spraying step S15b, a film forming step S15c, and a recovery step S15d.

(5) -1, temperature adjustment step S15a
The temperature adjustment step S15a is the same as the temperature adjustment step S4a described above.

(5) -2, spraying step S15b
The spraying step S15b is the same as the above-described spraying step S4b except that small particle size resin fine particle-attached toner base particles are used instead of the mixed resin fine particle-attached toner base particles.

(5) -3, film forming step S15c
The film-forming step S15c is the same as the film-forming step S4c described above, except that small particle size resin fine particle-attached toner base particles are used instead of the mixed resin fine particle-attached toner base particles.

(5) -4, Recovery step S15d
The collection step S15d is the same as the above-described collection step S4d.

  As described above, in the capsule toner manufacturing method of the present embodiment, since the large particle size resin fine particles are previously attached to the surface of the toner base particles, the large particle size resin fine particles are selectively attached to the concave portions of the toner base particles. It can suppress adhering to a convex part.

  Therefore, it is possible to apply sufficient stress due to mechanical impact force to all the amorphous resin fine particles adhering to the surface of the toner base particles, and the resin coating layer has a moderate and uniform degree of density, and a stronger resin coating layer. Can be formed.

  Therefore, the capsule toner obtained in the present embodiment is sufficiently mixed with the capsule toner newly supplied to the developing device because the resin coating layer is prevented from peeling even when stirred for a long time and the fluidity is good. It takes less time to enter. Further, since the degree of density of the resin coating layer is moderate, the release agent oozes out sufficiently during fixing, and sufficient offset resistance can be obtained.

(External additive)
The capsule toner thus obtained may be used as a capsule toner as it is, or an external additive may be added. Known external additives can be used, and examples thereof include silica and titanium oxide. These external additives are preferably surface-treated with a silicone resin, a silane coupling agent or the like.

  The amount of the external additive used is preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the capsule toner.

3. Two-component developer The capsule toner manufactured by the capsule toner manufacturing method of the present embodiment can also be used as a one-component developer composed of only toner, and as a two-component developer including a capsule toner and a carrier. Can also be used. When used as a one-component developer, the toner is frictionally charged using a blade, a fur brush, or the like, and adhered onto the developing sleeve, thereby conveying the capsule toner and performing image formation. When used as a two-component developer, the above capsule toner is used together with a carrier.

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

  The use ratio of the capsule toner and the carrier in the two-component developer is not particularly limited and can be appropriately selected according to the kind of the capsule toner and the carrier. For example, the capsule toner is 2 to 30% by weight of the total developer amount, preferably What is necessary is just to make it contain 2 to 20weight%.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.
[Glass transition point of binder resin, toner base particles and amorphous resin fine particles]
Using a differential scanning calorimeter (trade name: DSC220, manufactured by Seiko Denshi Kogyo Co., Ltd.), according to Japanese Industrial Standard (JIS) K7121-1987, 1 g of a sample was heated at a heating rate of 10 ° C. per minute and a DSC curve was measured. did. Draw the endothermic peak corresponding to the glass transition of the obtained DSC curve at a point where the slope is maximum with respect to the straight line that extends the base line on the high temperature side to the low temperature side and the curve from the rising part of the peak to the vertex. The glass transition point (Tg) was determined from the intersection with the tangent.

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

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

[Volume average particle diameter and coefficient of variation of toner base particles]
To 50 ml of electrolyte (trade name: ISOTON-II, manufactured by Beckman Coulter, Inc.), 20 mg of sample and 1 ml of sodium alkyl ether sulfate are added, and an ultrasonic disperser (trade name: desktop type dual frequency ultrasonic cleaner VS- D100 (manufactured by ASONE Co., Ltd.) was used for dispersion treatment 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 apparatus (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 of sample particles The volume average particle diameter and coefficient of variation were determined from the distribution.

[Volume average particle diameter and coefficient of variation of amorphous resin fine particles]
Measurement was performed using a laser diffraction / scattering particle distribution measuring apparatus (model: LA-920, manufactured by Horiba, Ltd.). In order to prevent the sample from aggregating, a dispersion in which the measurement sample was dispersed in an aqueous solution of Family Fresh (manufactured by Kao Corporation) was charged and stirred, and then injected into the apparatus. The measurement was performed twice to obtain an average. The measurement conditions were: measurement time: 30 seconds, particle refractive index: 1.4, particle shape: non-spherical, solvent: water, solvent refractive index: 1.33. The volume particle size distribution of the measurement sample was measured, and from the measurement results, the particle size at which the cumulative volume from the small particle size side in the cumulative volume distribution was 50% was determined as the volume average particle size (μm) of the sample. The coefficient of variation was determined from the volume particle size distribution of the measurement sample.

[Toner base particle shape factor SF2]
To a 100 ml beaker, 2.0 g of a sample, 1 ml of sodium alkyl ether sulfate and 50 ml of pure water were added and stirred well to prepare a sample dispersion. This dispersion was treated with an ultrasonic homogenizer (manufactured by Nippon Seiki Seisakusho Co., Ltd.) at an output of 50 μA for 5 minutes and further dispersed. After standing for 6 hours and removing the supernatant, 50 ml of pure water was added, and the mixture was stirred with a magnetic stirrer for 5 minutes, and then subjected to suction filtration using a membrane filter (caliber: 1 μm). The washed product on the membrane filter was vacuum-dried in a desiccator containing silica gel for about overnight.

A metal film (Au film, film thickness 0.5 μm) was formed by sputtering deposition on the surface of the sample whose surface was cleaned in this way. About 500 pieces of this metal film coated sample were randomly extracted with a scanning electron microscope (trade name: S-570, manufactured by Hitachi, Ltd.) at an acceleration voltage of 5 kV and a magnification of 1000 times. I took a picture. The electron micrograph data was subjected to image analysis with image analysis software (trade name: A image-kun, manufactured by Asahi Kasei Engineering Co., Ltd.). The analysis parameters of the image analysis software “A image-kun” are: small figure removal area: 100 pixels, shrinkage separation: number of times 1; small figure: 1; number of times: 10, noise removal filter: none, shading: none, result display unit: μm. From the maximum length MXLNG, the perimeter length PERI, and the graphic area AREA of the aggregated particles obtained in this way, the shape factor SF2 was obtained by the following equation (2).
SF2 = {(PERI) ² / AREA} × (100 / 4π) (2)

[Production of toner base particles]
-Polyester resin (trade name: Toughton, glass transition point 60 ° C, softening point 138 ° C, manufactured by Kao Corporation) 85 parts by weight I. Pigment Blue 15: 3 5 parts by weight Release agent (trade name: Carnauba wax, melting point 82 ° C., manufactured by Toa Kasei Co., Ltd.)
8 parts by weight Charge control agent (trade name: Bontron E84, Orient Chemical Co., Ltd.) 2 parts by weight

  The above toner raw materials are premixed with a Henschel mixer (trade name: FM20C, manufactured by Mitsui Mining Co., Ltd.), and then a cylinder set temperature is set using a twin-screw extruder (trade name: PCM-30, manufactured by Ikekai Co., Ltd.). The mixture was melt-kneaded at 110 ° C., barrel rotation speed of 300 rpm (300 rpm), and a raw material supply rate of 20 kg / hour to obtain a melt-kneaded product.

  The melt-kneaded product is cooled with a cooling belt, coarsely pulverized with a speed mill having a 2 mm screen, and finely pulverized with a jet type pulverizer (trade name: IDS-2, manufactured by Nippon Pneumatic Industry Co., Ltd.). A pulverized product was obtained.

  By classifying this finely pulverized product with an elbow jet classifier (trade name: EJ-15-3, manufactured by Nippon Steel Mining Co., Ltd.), the volume average particle diameter is 6.9 μm, and the coefficient of variation is 22. Toner mother particles having a softening point of 116 ° C., a glass transition point of 55 ° C., and a shape factor SF2 of 140 were obtained.

[Preparation of amorphous resin fine particles]
Styrene, acrylic acid and butyl acrylate were polymerized to obtain amorphous resin fine particles. This was further dehydrated and dried using a dryer (manufactured by Fujisaki Electric Co., Ltd., Model: Micro Mist Dryer MDL-050) to obtain amorphous resin fine particles A.

  In such a method for producing amorphous resin fine particles, amorphous resin fine particles B to R were obtained by appropriately changing the addition amount of styrene, acrylic acid and butyl acrylate, polymerization time, polymerization temperature and the like. . Table 1 shows the physical properties of the amorphous resin fine particles A to R.

Example 1
[Amorphous resin fine particle adhesion step S3]
[Mixed resin particle production step S3a]
500 g of amorphous resin fine particles A (large particle size resin fine particles) and 500 g of amorphous resin fine particles B (small particle size resin fine particles) are put into a Henschel mixer 20B (Mitsui Mining Co., Ltd.), and the peripheral speed of the stirring blades Mixing was performed at 40 m / sec for 3 minutes to prepare mixed resin fine particles.

[Mixed resin particle adhesion step S3b]
100 parts by weight of the toner base particles and 10 parts by weight of the mixed resin fine particles are charged into a Henschel mixer 20B (Mitsui Mining Co., Ltd.) and mixed for 3 minutes at a stirring blade peripheral speed of 40 m / sec. Base particles were prepared.

[Film-forming step S4]
A device provided with a spray unit in a hybridization system (trade name: NHS-1 type, manufactured by Nara Machinery Co., Ltd.) according to the device shown in FIG. 2 was used.

  The spray unit is a two-fluid nozzle (trade name: HM-6 type, manufactured by Fuso Seiki Co., Ltd.) through a liquid feed pump (trade name: SP11-12, manufactured by FROM Co., Ltd.). It was connected so that a fixed amount of liquid was fed. The spraying speed and liquid gas discharging speed of the spray liquid can be observed using a commercially available gas detector (trade name: XP-3110, manufactured by Shin Cosmos Electric Co., Ltd.).

The mounting angle of the two-fluid nozzle was set so that the spray angle θ was 0 °.
The temperature adjustment jacket was provided on the entire surface of the powder flow section and the stirring section wall, and a temperature sensor was attached to the powder flow path.

[Temperature adjustment step S4a]
It adjusted so that the temperature of a powder flow part and a stirring part might be set to 45 degreeC.

[Spraying Step S4b, Film Forming Step S4c]
The mixed resin fine particle adhering toner mother particles are put into the powder flow path, and the peripheral speed at the outermost periphery of the rotary stirring means 204 is stirred and mixed for 3 minutes at a rotation speed of 8000 rpm, and then the spray liquid is supplied from the spray unit. Sprayed.

  The spray liquid was sprayed for 40 minutes at a spray rate of 0.5 g / min and an air flow rate of 5 L / min, and the mixed resin fine particles were formed into a film on the surface of the toner base particles.

  After stopping the spraying of the spray liquid, the mixture was stirred for 5 minutes to obtain a capsule toner (volume average particle diameter 7.2 μm, coefficient of variation 25). At this time, the discharge concentration of the spray liquid discharged through the through hole and the gas discharge portion was stable at about 1.4 Vol%. Moreover, the air flow rate sent into the apparatus was adjusted to 5 L / min, and the total air flow rate from the two-fluid nozzle was 10 L / min.

[Recovery Step S4d]
The capsule toner in the powder flow path was recovered from the powder recovery unit.

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

(Examples 2 to 18)
Capsule toners of Examples 2 to 18 were obtained in the same manner as in Example 1 except that the large particle size resin particles and the small particle size resin particles were changed as shown in Table 2.

(Example 19)
Instead of the amorphous resin fine particle adhesion step S3, the following large particle size resin fine particle adhesion step S13 and small particle size resin fine particle adhesion step S14 are performed. A capsule toner of Example 19 was obtained in the same manner as in Example 1 except that the toner particles with small particle size resin fine particles were used instead of the particles.

[Large particle size resin fine particle adhesion step S13]
100 parts by weight of toner base particles and 5 parts by weight of amorphous resin fine particles A (large particle size resin fine particles) are put into the Henschel mixer 20B and mixed for 3 minutes at a peripheral speed of the stirring blade of 40 m / sec. Then, non-crystalline resin fine particles A were adhered to the surface of the toner base particles to obtain toner base particles with large particle size resin fine particles.

[Small particle size resin fine particle adhesion step S14]
Subsequently, 5 parts by weight of amorphous resin fine particles B (small particle size resin fine particles) are charged into the Henschel mixer 20B and mixed for 3 minutes at a peripheral speed of the stirring blade of 40 m / sec. Amorphous resin fine particles B were adhered to the surface of the fine particle-adhered toner base particles to obtain small particle size resin fine particle-adhered toner mother particles. The obtained toner base particles with small particle size resin fine particles were collected in a polyethylene storage bag.

(Examples 20 and 21)
Capsule toners of Examples 20 and 21 were obtained in the same manner as Example 19 except that the large particle size resin particles and the small particle size resin particles were changed as shown in Table 2.

(Comparative Example 1)
The mixed resin fine particle production step S3a is not performed, and in the mixed resin fine particle adhesion step S3b, only the amorphous resin fine particles A are used instead of the mixed resin fine particles, and the toner base particles to which the amorphous resin fine particles are adhered are produced. The capsule toner of Comparative Example 1 was used in the same manner as in Example 1 except that the toner base particles to which the amorphous resin fine particles adhered were used instead of the mixed resin fine particle-adhered toner base particles in the film forming step S4. Obtained.

(Comparative Examples 2 and 3)
Capsule toners of Comparative Examples 2 and 3 were obtained in the same manner as Comparative Example 1 except that the amorphous resin fine particles shown in Table 2 were used instead of the amorphous resin fine particles A. In Table 2, the amorphous resin fine particles used in Comparative Examples 1 to 3 are listed in the column of large particle size resin fine particles.

[Preparation of two-component developer]
The capsule toners of Examples 1 to 21 and Comparative Examples 1 to 3 and the ferrite core carrier having a volume average particle diameter of 60 μm were mixed so that the toner concentration would be 7%, and Examples 1 to 21 and Comparative Example 1 were mixed. Two-component developers each containing ˜3 capsule toners were prepared.

<Evaluation>
[Liquidity]
The developer tank of a commercial copying machine (trade name: MX-2300G, manufactured by Sharp Corporation) is filled with the above two-component developer, and this is placed in a constant temperature and humidity chamber set at a temperature of 50 ° C. and a humidity of 50%. It installed in the state integrated in the idling machine, and was idling at 275 rpm for 2 hours.

  Next, the developing tank was taken out from the constant temperature and humidity tank, and 1 g of toner was supplied to the toner supply position. Thereafter, idling was performed at 275 rpm, and the output value transition from the ATC sensor was recorded with a digital oscilloscope (trade name: LT224, manufactured by LeCroy Japan Co., Ltd.).

  From the recorded output value, a time T1 [second] until the maximum value-minimum value of the sensor output for 2 seconds before and after was within 0.5 V was derived. T1-T0 [seconds], where T0 [seconds] is the time when the idling was started, was set as the toner mixing settling time, and the developer flowability was evaluated using the settling time.

The evaluation criteria for liquidity are as follows.
A: Very good. Settling time is 15 seconds or less.
○: Good. The settling time is longer than 15 seconds and shorter than 20 seconds.
Δ: No practical problem. The settling time is longer than 20 seconds and shorter than 30 seconds.
X: Defect. Settling time exceeds 30 seconds.
Table 2 shows the types of amorphous resin fine particles, evaluation results, and the like.

  In the capsule toners of Examples 1 to 7, the volume average particle size of the large particle size resin fine particles and the volume average particle size of the small particle size resin fine particles, and the ratio thereof are set within a specified range, whereby the resin coating layer It is estimated that the degree of density can be optimized and a strong and uniform resin coating layer can be formed. Therefore, even when stirring and mixing for a long time, the resin coating layer was prevented from being peeled off from the toner base particles, and good fluidity could be maintained. Further, as a result of evaluating the fixing property, it was confirmed that sufficient offset resistance was obtained, and that the release agent exudes sufficiently during fixing.

  In the capsule toners of Examples 8 to 15, the ratio (particle size ratio) between the volume average particle size of the large particle size resin fine particles and the volume average particle size of the small particle size resin fine particles is out of the preferred range. It is presumed that the uniformity of the coating layer and the adhesion strength to the toner base particles were lowered. For this reason, the settling time until the toner is mixed is longer than that of the capsule toners of Examples 1 to 7, but the level is not problematic in practical use. Further, as a result of evaluating the fixing property, it was confirmed that sufficient offset resistance was obtained, and that the release agent exudes sufficiently during fixing.

  In the capsule toner of Example 16, the particle size ratio is set within a specified range, but the volume average particle size of the small particle size resin fine particles is out of the preferred range. Therefore, the amorphous resin fine particle adhesion step S3. , The aggregation of the resin particles with small particle diameters was remarkable, and it was estimated that the secondary aggregates were not sufficiently crushed. Therefore, the uniformity of the resin coating layer and the adhesion strength to the toner base particles are reduced, and the settling time until the toner is mixed is longer than that of the capsule toners of Examples 1 to 7, but there is no practical problem. It was a level. Further, as a result of evaluating the fixing property, it was confirmed that sufficient offset resistance was obtained, and that the release agent exudes sufficiently during fixing.

  In the capsule toners of Examples 17 and 18, the particle size ratio is set within a specified range, but the volume average particle size of the large particle size resin fine particles is out of the preferred range. It is presumed that the toner was easily detached from the toner base particles. Therefore, the adhesion strength of the resin coating layer to the toner base particles is reduced, and the settling time until the toner is mixed is longer than that of the capsule toners of Examples 1 to 7, but the level is not problematic in practical use. It was. Further, as a result of evaluating the fixing property, it was confirmed that sufficient offset resistance was obtained, and that the release agent exudes sufficiently during fixing.

  In the capsule toners of Examples 19, 20, and 21, only the large particle size resin fine particles were previously attached to the surface of the toner mother particle, so that the concave portions of the toner mother particles were filled with the large particle size resin fine particles that are subject to stress. Small particle size resin fine particles were adhered. Therefore, the resin particles having large particle diameters selectively adhere to the concave portions of the toner base particles, and sufficient stress can be applied to all the amorphous resin fine particles attached to the surface of the toner base particles. It is presumed that a uniform and stronger resin coating layer than the toner could be formed. Therefore, the settling time until the toner is mixed is shorter than in the capsule toners of Examples 1 to 18, and high fluidity is obtained. Further, as a result of evaluating the fixing property, it was confirmed that sufficient offset resistance was obtained, and that the release agent exudes sufficiently during fixing.

  In the capsule toners of Comparative Examples 1, 2, and 3, the resin coating layer is formed only with a single amorphous resin fine particle. Therefore, the degree of density of the resin coating layer is smaller than that of the capsule toner of the example, and the toner It is presumed that the adhesion strength between the mother particles and the amorphous resin fine particles or the adhesion strength between the amorphous resin fine particles is lowered. Accordingly, it is considered that when stirring for a long time, the fluidity is lowered, and the settling time until the toner is mixed becomes longer.

DESCRIPTION OF SYMBOLS 201 Toner manufacturing apparatus 202 Powder flow path 203 Spraying means 204 Rotating stirring means 206 Powder input part 207 Powder collection part 208 Stirring part 208a End wall 208b Peripheral wall 208c End wall 209 Powder flow-through part 210, 211 Opening part 212 Supply pipe 213, 217 Solenoid valve 215 Recovery tank 216 Recovery pipe 218 Rotating shaft member 219 Disc-shaped rotary disk 220 Multiple stirring blades 221 Through hole 222 Gas discharge part A200 Cutting plane line θ Spray angle Φ Spray liquid spreading angle

Claims (6)

Toner base particles containing a binder resin and a colorant;
A resin coating layer provided on the surface of a toner base particle, comprising a first amorphous resin fine particle made of a first amorphous resin and a second amorphous resin, which is more than the first amorphous resin fine particle. And a resin coating layer formed by forming a film of second amorphous resin fine particles having a small volume average particle diameter. The volume average particle diameter d1 of the first amorphous resin fine particles is 500 nm or less, the volume average particle diameter d2 of the second amorphous resin fine particles is 20 nm or more,
The volume average particle diameter d1 of the first amorphous resin fine particles and the volume average particle diameter d2 of the second amorphous resin fine particles satisfy the following formula (1). Capsule toner.
0.1 ≦ d2 / d1 ≦ 0.7 (1) First amorphous resin fine particles made of the first amorphous resin, and second amorphous resin fine particles made of the second amorphous resin and having a volume average particle diameter smaller than that of the first amorphous resin fine particles, The toner base particles containing the binder resin and the colorant are stirred and mixed, and the first amorphous resin fine particles and the second amorphous resin fine particles are adhered to the surface of the toner base particles to obtain the mixed resin fine particle-attached toner base particles. Obtaining amorphous resin fine particles attaching step;
A spraying step of spraying a spray liquid, which is a liquid for plasticizing the toner base particles, the first amorphous resin fine particles, and the second amorphous resin fine particles, onto the mixed resin fine particle-attached toner base particles in a fluid state with stirring. When,
While spraying the spray liquid, stirring is continued until the first amorphous resin fine particles and the second amorphous resin fine particles contained in the mixed resin fine particle-adhered toner mother particles are softened to form a film. And a film-forming step of forming a resin coating layer on the surface of the particles. The amorphous resin fine particle adhesion step includes:
A mixed resin fine particle production step of stirring and mixing the first amorphous resin fine particles and the second amorphous resin fine particles to obtain mixed resin fine particles;
And a mixed resin fine particle adhering step of stirring and mixing the toner base particles and the mixed resin fine particles to adhere the mixed resin fine particles to the surface of the toner mother particles to obtain the mixed resin fine particle-attached toner mother particles. Item 4. A method for producing a capsule toner according to Item 3. The toner base particles containing the binder resin and the colorant and the first amorphous resin fine particles made of the first amorphous resin are agitated and mixed to adhere the first amorphous resin fine particles to the surface of the toner base particles. A first amorphous resin fine particle attaching step of obtaining first amorphous resin fine particle attached toner base particles;
The second amorphous resin fine particles, which are made of the second amorphous resin and have a volume average particle diameter smaller than the first amorphous resin fine particles, and the first amorphous resin fine particle-attached toner base particles are stirred and mixed. A second amorphous resin fine particle attachment step of obtaining second amorphous resin fine particle-attached toner mother particles by attaching second amorphous resin fine particles to the surface of the first amorphous resin fine particle-attached toner mother particles;
A spray liquid which is a liquid for plasticizing the toner base particles, the first amorphous resin fine particles, and the second amorphous resin fine particles is used as the second amorphous resin fine particle-attached toner base particles in a fluid state under stirring. A spraying process for spraying;
While spraying the spray liquid, stirring is continued until the first amorphous resin fine particles and the second amorphous resin fine particles contained in the second amorphous resin fine particle-adhered toner base particles are softened to form a film. And a film forming step of forming a resin coating layer on the surface of the toner base particles. The volume average particle diameter d1 of the first amorphous resin fine particles is 500 nm or less, the volume average particle diameter d2 of the second amorphous resin fine particles is 20 nm or more,
The volume average particle diameter d1 of the first amorphous resin fine particles and the volume average particle diameter d2 of the second amorphous resin fine particles satisfy the following formula (1): The manufacturing method of the capsule toner as described in any one.
0.1 ≦ d2 / d1 ≦ 0.7 (1)

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