JP5381914B2 - Toner for electrostatic image development - Google Patents

Description

  The present invention is an electrostatic charge image developing toner (hereinafter, sometimes simply referred to as “toner”) used for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing, and the like. About.

  In an image forming apparatus such as an electrophotographic apparatus, an electrostatic recording apparatus, and an electrostatic printing apparatus, a desired image is formed by developing an electrostatic latent image formed on a photoreceptor with toner for developing an electrostatic image. This technique is widely used. Such a technique is applied to a copying machine, a printer, a facsimile machine, and a multifunction machine of these.

  For example, an electrophotographic apparatus using an electrophotographic method generally forms the electrostatic latent image on the photoreceptor after the surface of the photoreceptor made of a photoconductive material is uniformly charged by various means. . Next, the electrostatic latent image is developed using toner, the toner image is transferred onto a recording material such as paper, and then fixed by heating or the like to obtain a copy.

The toner used for development includes a negatively chargeable toner and a positively chargeable toner. An electrophotographic apparatus using a positively chargeable toner has been used preferably in recent years because it generates less ozone and provides good chargeability.
Further, on the surface of toner particles used for development, in order to improve the charging stability, fluidity, durability and the like of the toner, inorganic fine particles and organic fine particles generally having a smaller particle diameter than colored resin particles (toner particles). External additives such as these are externally added (attached).

  In a toner using a conventional external additive, in the process of continuous printing of a large number of sheets, the external additive may be caused by mechanical stress in the developing device (increased number of contact between toner particles due to stirring or the like). The toner particles are buried inside and / or released (desorbed) from the surface of the toner particles. For this reason, the function of the external additive is lowered, and it becomes difficult to impart to the toner particles a stable charging property (charging stability) over time.

  In addition, the toner particles embedded with the external additive cause a phenomenon (filming phenomenon) in which the toner particles adhere to the surface of the photoreceptor, and image quality is likely to be deteriorated due to fogging or the like. The external additive released (desorbed) from the surface of the toner particles deteriorates the charging characteristics of the surface of the photoreceptor, and causes the printing durability and image quality of the toner to deteriorate. Especially under high temperature and high humidity conditions, the image quality is significantly deteriorated by filming.

Therefore, even when the number of contact between the toner particles by stirring or the like increases in the developing device as in the case of continuous printing of a large number of sheets, problems such as embedding and / or releasing of the external additive do not occur. There is a demand for a toner that maintains a state in which an external additive is suitably attached over time and maintains a stable chargeability (charging stability).
Patent Document 1 discloses a toner using inorganic / organic composite fine particles in which inorganic fine particles are fixed on the surface of organic fine particles as an external additive.

Japanese Patent Laid-Open No. 2002-131976

  In Patent Document 1, in paragraph [0064] of the specification of the document, as a means for fixing inorganic fine particles to the surface of organic fine particles, a method of mixing organic fine particles and inorganic fine particles and then applying heat, organic fine particles It is described that a so-called mechanochemical method or the like for mechanically fixing inorganic fine particles to the surface is used. However, with such a manufacturing method, it is difficult to cover the entire surface of the organic fine particles serving as the core with inorganic fine particles. Further, as a result of studies by the present inventors, it has been found that the toner described in Patent Document 1 is likely to cause fogging, particularly fogging under high temperature and high humidity.

  An object of the present invention is to provide a toner for developing an electrostatic charge image that suppresses a decrease in toner charge amount and occurrence of fog in a high-temperature and high-humidity environment and has excellent fluidity.

  As a result of diligent studies to achieve the above object, the present inventor can improve the environmental stability of toner by using core-shell type composite particles in which the surface of resin particles is coated with silica as an external additive. In particular, a decrease in toner charge amount in a high temperature and high humidity environment is suppressed, there is no fogging in that environment, stable printing can be performed, and furthermore, a very high toner fluidity is exhibited. As a result, the present invention was completed.

That is, the electrostatic image developing toner of the present invention is a toner for developing an electrostatic image containing a colored resin particle containing a binder resin and a colorant and an external additive, wherein the external additive is a resin. The volume ratio of the silica component of the composite fine particle is 45 to 75 volume when the surface of the fine particle is a core-shell type composite fine particle coated with a continuous layer of silica and the total volume of the composite fine particle is 100% by volume. %.

  In the present invention, the adsorbed moisture content of the core-shell composite fine particles is preferably 0.5 to 1.5% by mass.

  In this invention, it is preferable that the addition amount of the said core-shell type composite fine particle is 0.1-20 mass parts with respect to 100 mass parts of said colored resin particles.

  In the present invention, the colored resin particles preferably have a volume average particle size of 4 to 12 μm and an average circularity of 0.96 to 1.00.

  In the present invention, it is preferable that both the colored resin particles and the core-shell composite fine particles exhibit positive chargeability.

  In the present invention, the number average particle size of the core-shell composite fine particles is preferably 30 to 300 nm.

  In the present invention, it is preferable that the value of the blow-off charge amount of the core-shell type composite fine particles is +1000 to +4000 μC / g.

  In the present invention, the resin fine particles of the core-shell composite fine particles are preferably a crosslinked resin.

  According to the toner for developing an electrostatic charge image of the present invention as described above, by using the core-shell type composite fine particles in which the surface of the resin fine particles is coated with silica as an external additive, the toner has stable charging characteristics over time. Even if it is applied to particles and subjected to continuous printing of a large number of sheets, image quality deterioration due to fog or the like hardly occurs and an electrostatic charge image developing toner having further excellent fluidity is provided.

  The electrostatic image developing toner of the present invention is a colored resin particle containing a binder resin and a colorant, and an electrostatic image developing toner containing an external additive, wherein the external additive is a resin fine particle. The core-shell type composite fine particles whose surface is coated with silica, and the volume ratio of the silica component of the composite fine particles when the total volume of the composite fine particles is 100% by volume is 45 to 75% by volume. Features.

Hereinafter, the toner for developing an electrostatic charge image of the present invention (hereinafter sometimes simply referred to as “toner”) will be described.
The toner of the present invention is obtained by adhering and adding (externally adding) core-shell type composite fine particles whose surface of resin fine particles are coated with silica to colored resin particles containing a binder resin and a colorant as external additives. It is done.
Hereinafter, a method for producing colored resin particles used in the present invention, a colored resin particle obtained by the production method, a method for producing core-shell composite fine particles used as an external additive in the invention, and a core shell obtained by the production method The production method of the toner of the present invention using the mold composite fine particles, the colored resin particles and the external additive, and the toner of the present invention will be described in order.

1. Production method of colored resin particles Generally, the production method of colored resin particles is roughly classified into dry methods such as a pulverization method, and wet methods such as an emulsion polymerization aggregation method, a suspension polymerization method, and a dissolution suspension method. The wet method is preferable because it is easy to obtain a toner excellent in printing characteristics such as the property. Among wet methods, a polymerization method such as an emulsion polymerization aggregation method and a suspension polymerization method is preferable because a toner having a relatively small particle size distribution on the order of microns is preferable. A suspension polymerization method is more preferable among polymerization methods. preferable.

  In the emulsion polymerization aggregation method, an emulsified polymerizable monomer is polymerized to obtain a resin fine particle emulsion, which is aggregated with a colorant dispersion or the like to produce colored resin particles. The dissolution suspension method produces droplets of a solution in which toner components such as a binder resin and a colorant are dissolved or dispersed in an organic solvent in an aqueous medium, and the organic solvent is removed to produce colored resin particles. Each of which is a known method.

  The colored resin particles of the present invention can be produced by employing a wet method or a dry method. Among the wet methods, a preferred suspension polymerization method is adopted, and the following process is performed.

(A) Suspension polymerization method (A-1) Preparation step of polymerizable monomer composition First, a polymerizable monomer, a colorant, and a charge control agent and a release agent added as necessary. Other additives are mixed to prepare a polymerizable monomer composition. The mixing at the time of preparing the polymerizable monomer composition is performed using, for example, a media type dispersing machine.

  In the present invention, the polymerizable monomer means a monomer having a polymerizable functional group, and the polymerizable monomer is polymerized to become a binder resin. It is preferable to use a monovinyl monomer as the main component of the polymerizable monomer. Examples of the monovinyl monomer include styrene; styrene derivatives such as vinyl toluene and α-methylstyrene; acrylic acid and methacrylic acid; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, acrylic acid 2 Acrylic esters such as ethylhexyl and dimethylaminoethyl acrylate; methacrylic esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate and dimethylaminoethyl methacrylate; acrylonitrile And nitrile compounds such as methacrylonitrile; amide compounds such as acrylamide and methacrylamide; olefins such as ethylene, propylene, and butylene. These monovinyl monomers can be used alone or in combination of two or more. Of these, styrene, styrene derivatives, and acrylic acid or methacrylic acid derivatives are preferably used as the monovinyl monomer.

In order to improve hot offset and storage stability, it is preferable to use any crosslinkable polymerizable monomer together with the monovinyl monomer. A crosslinkable polymerizable monomer means a monomer having two or more polymerizable functional groups. Examples of the crosslinkable polymerizable monomer include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof; alcohols having two or more hydroxyl groups such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate; Examples include ester compounds in which two or more carboxylic acids are ester-bonded; other divinyl compounds such as N, N-divinylaniline and divinyl ether; compounds having three or more vinyl groups. These crosslinkable polymerizable monomers can be used alone or in combination of two or more.
In the present invention, the crosslinkable polymerizable monomer is usually used at a ratio of 0.1 to 5 parts by mass, preferably 0.3 to 2 parts by mass with respect to 100 parts by mass of the monovinyl monomer. desirable.

  Furthermore, it is preferable to use a macromonomer as a part of the polymerizable monomer because the balance between the storage stability of the obtained toner and the fixing property at low temperature is improved. The macromonomer has a polymerizable carbon-carbon unsaturated double bond at the end of the molecular chain, and is a reactive oligomer or polymer having a number average molecular weight of usually 1,000 to 30,000. The macromonomer is preferably one that gives a polymer having a higher Tg than the glass transition temperature of the polymer obtained by polymerizing the monovinyl monomer (hereinafter sometimes referred to as “Tg”). The macromonomer is preferably used in an amount of 0.03 to 5 parts by mass, more preferably 0.05 to 1 part by mass, with respect to 100 parts by mass of the monovinyl monomer.

In the present invention, a colorant is used. However, when producing a color toner, black, cyan, yellow, and magenta colorants can be used.
As the black colorant, carbon black, titanium black, magnetic powder such as iron zinc oxide and nickel iron oxide can be used.

  As the cyan colorant, for example, a copper phthalocyanine compound, a derivative thereof, and an anthraquinone compound can be used. Specifically, C.I. I. Pigment blue 2, 3, 6, 15, 15: 1, 15: 2, 15: 3, 15: 4, 16, 17: 1, 60, and the like.

  Examples of the yellow colorant include monoazo pigments, azo pigments such as disazo pigments, and compounds such as condensed polycyclic pigments. I. Pigment yellow 3, 12, 13, 14, 15, 17, 62, 65, 73, 74, 83, 93, 97, 120, 138, 155, 180, 181, 185, and 186.

  As the magenta colorant, monoazo pigments, azo pigments such as disazo pigments, and compounds such as condensed polycyclic pigments are used. I. Pigment Red 31, 48, 57: 1, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 149, 150, 163, 170, 184, 185, 187, 202, 206, 207, 209, 237, 251, 269 and C.I. I. Pigment violet 19 and the like.

  In the present invention, each colorant can be used alone or in combination of two or more. The amount of the colorant is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the monovinyl monomer.

As other additives, a positively or negatively chargeable charge control agent can be used to improve the chargeability of the toner.
The charge control agent is not particularly limited as long as it is generally used as a charge control agent for toner, but among charge control agents, the compatibility with the polymerizable monomer is high, and stable chargeability. (Charge stability) can be imparted to the toner particles, and therefore a positively or negatively chargeable charge control resin is preferred. Further, from the viewpoint of obtaining a positively chargeable toner, a positively chargeable charge control resin is preferred. More preferably used.
Examples of positively chargeable charge control agents include nigrosine dyes, quaternary ammonium salts, triaminotriphenylmethane compounds and imidazole compounds, polyamine resins as charge control resins that are preferably used, and quaternary ammonium group-containing copolymers. , And quaternary ammonium base-containing copolymers.
Negatively chargeable charge control agents include azo dyes containing metals such as Cr, Co, Al, and Fe, salicylic acid metal compounds and alkylsalicylic acid metal compounds, and sulfonic acid group containing charge control resins that are preferably used Examples thereof include a copolymer, a sulfonate group-containing copolymer, a carboxylic acid group-containing copolymer, and a carboxylic acid group-containing copolymer.
In the present invention, the charge control agent is usually used in a proportion of 0.01 to 10 parts by mass, preferably 0.03 to 8 parts by mass, with respect to 100 parts by mass of the monovinyl monomer. If the addition amount of the charge control agent is less than 0.01 parts by mass, fog may occur. On the other hand, when the addition amount of the charge control agent exceeds 10 parts by mass, printing stains may occur.

As other additives, it is preferable to use a molecular weight modifier when polymerizing a polymerizable monomer that is polymerized to become a binder resin.
The molecular weight modifier is not particularly limited as long as it is generally used as a molecular weight modifier for toner. For example, t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, and 2,2, Mercaptans such as 4,6,6-pentamethylheptane-4-thiol; tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, N, N′-dimethyl-N, N′-diphenylthiuram disulfide, N, And thiuram disulfides such as N′-dioctadecyl-N, N′-diisopropylthiuram disulfide; These molecular weight modifiers may be used alone or in combination of two or more.
In this invention, it is desirable to use a molecular weight modifier in the ratio of 0.01-10 mass parts normally with respect to 100 mass parts of monovinyl monomers, Preferably it is 0.1-5 mass parts.

Furthermore, it is preferable to add a release agent as another additive. By adding a release agent, the releasability of the toner from the fixing roll during fixing can be improved. Any releasing agent can be used without particular limitation as long as it is generally used as a releasing agent for toner. For example, low molecular weight polyolefin wax and modified wax thereof; plant natural wax such as jojoba; petroleum wax such as paraffin; mineral wax such as ozokerite; synthetic wax such as Fischer-Tropsch wax; polyhydric alcohol such as dipentaerythritol ester Ester; etc. are mentioned. A polyhydric alcohol ester is preferable because the storage stability of the toner and the low-temperature fixability can be balanced. These may be used alone or in combination of two or more.
The release agent is preferably used in an amount of 0.1 to 30 parts by mass, and more preferably 1 to 20 parts by mass with respect to 100 parts by mass of the monovinyl monomer.

(A-2) Suspension step for obtaining a suspension (droplet formation step)
In the present invention, a polymerizable monomer composition containing a polymerizable monomer and a colorant is dispersed in an aqueous medium containing a dispersion stabilizer, a polymerization initiator is added, and then the polymerizable monomer composition is added. Droplet formation is performed. The method for forming droplets is not particularly limited. For example, an (in-line type) emulsifying disperser (trade name “Milder” manufactured by Ebara Manufacturing Co., Ltd.), a high-speed emulsifying disperser (trade name “T. K. Homomixer MARK Type II ") or the like capable of strong stirring.

  As a polymerization initiator, persulfates such as potassium persulfate and ammonium persulfate: 4,4′-azobis (4-cyanovaleric acid), 2,2′-azobis (2-methyl-N- (2- Hydroxyethyl) propionamide), 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis (2,4-dimethylvaleronitrile), and 2,2′-azobisisobutyro Azo compounds such as nitrile; di-t-butyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylbutanoate, diisopropyl peroxydicarbonate, And organic peroxides such as di-t-butylperoxyisophthalate and t-butylperoxyisobutyrate. That. These can be used alone or in combination of two or more. Among these, it is preferable to use an organic peroxide because residual polymerizable monomers can be reduced and printing durability is excellent.

  Among organic peroxides, peroxyesters are preferred because of the high initiator efficiency and the remaining polymerizable monomer can be reduced. Non-aromatic peroxyesters, that is, peroxyesters having no aromatic ring Is more preferable.

  As described above, the polymerization initiator may be added before the droplet formation after the polymerizable monomer composition is dispersed in the aqueous medium. However, the polymerization initiator is not dispersed in the aqueous medium. It may be added to the monomer composition.

  The addition amount of the polymerization initiator used for the polymerization of the polymerizable monomer composition is preferably 0.1 to 20 parts by mass, more preferably 0.3 to 100 parts by mass of the monovinyl monomer. It is -15 mass parts, Most preferably, it is 1-10 mass parts.

  In the present invention, the aqueous medium refers to a medium containing water as a main component.

  In the present invention, the aqueous medium preferably contains a dispersion stabilizer. Examples of the dispersion stabilizer include sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate and magnesium carbonate; phosphates such as calcium phosphate; metals such as aluminum oxide and titanium oxide. Oxides; metal hydroxides such as aluminum hydroxide, magnesium hydroxide, and ferric hydroxide; inorganic compounds such as; water-soluble polymers such as polyvinyl alcohol, methylcellulose, and gelatin; anionic surfactants; Organic compounds such as nonionic surfactants; amphoteric surfactants; The said dispersion stabilizer can be used 1 type or in combination of 2 or more types.

  Among the above dispersion stabilizers, inorganic compounds, particularly colloids of poorly water-soluble metal hydroxides are preferred. By using a colloid of an inorganic compound, particularly a poorly water-soluble metal hydroxide, the particle size distribution of the colored resin particles can be narrowed, and the residual amount of the dispersion stabilizer after washing can be reduced. The polymerized toner can reproduce an image clearly and does not deteriorate environmental stability.

(A-3) Polymerization step As in (A-2) above, droplet formation is performed, the resulting aqueous dispersion medium is heated to initiate polymerization, and an aqueous dispersion of colored resin particles is formed.
The polymerization temperature of the polymerizable monomer composition is preferably 50 ° C. or higher, more preferably 60 to 95 ° C. The polymerization reaction time is preferably 1 to 20 hours, more preferably 2 to 15 hours.

  The colored resin particles may be used as a polymerized toner by adding an external additive as it is, but the so-called core-shell type obtained by using the colored resin particles as a core layer and forming a shell layer different from the core layer on the outside thereof. It is preferable to use colored resin particles (also referred to as “capsule type”). The core-shell type colored resin particles balance the reduction of the fixing temperature and the prevention of aggregation during storage by coating the core layer made of a material having a low softening point with a material having a higher softening point. be able to.

  There is no restriction | limiting in particular as a method of manufacturing a core shell type colored resin particle using the said colored resin particle mentioned above, It can manufacture by a conventionally well-known method. An in situ polymerization method and a phase separation method are preferable from the viewpoint of production efficiency.

A method for producing core-shell type colored resin particles by in situ polymerization will be described below.
Addition of a polymerizable monomer (polymerizable monomer for shell) and a polymerization initiator to form a shell layer into an aqueous medium in which colored resin particles are dispersed, and then polymerize to form a core-shell type color. Resin particles can be obtained.

  As the polymerizable monomer for the shell, the same monomers as the aforementioned polymerizable monomers can be used. Among them, it is preferable to use monomers such as styrene, acrylonitrile, and methyl methacrylate, which can obtain a polymer having a Tg exceeding 80 ° C., alone or in combination of two or more.

  As a polymerization initiator used for polymerization of the polymerizable monomer for shell, persulfate metal salts such as potassium persulfate and ammonium persulfate; 2,2′-azobis (2-methyl-N- (2-hydroxyethyl) Water-soluble such as azo initiators such as) propionamide) and 2,2′-azobis- (2-methyl-N- (1,1-bis (hydroxymethyl) 2-hydroxyethyl) propionamide); A polymerization initiator can be mentioned. These can be used alone or in combination of two or more. The amount of the polymerization initiator is preferably 0.1 to 30 parts by mass, and more preferably 1 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer for shell.

  The polymerization temperature of the shell layer is preferably 50 ° C. or higher, more preferably 60 to 95 ° C. The polymerization reaction time is preferably 1 to 20 hours, more preferably 2 to 15 hours.

(A-4) Washing, filtration, dehydration, and drying steps The aqueous dispersion of colored resin particles obtained by polymerization is washed, dehydrated, and filtered to remove the dispersion stabilizer according to a conventional method after completion of the polymerization. The drying operation is preferably repeated several times as necessary.

  As the above washing method, when an inorganic compound is used as the dispersion stabilizer, the dispersion stabilizer can be dissolved in water and removed by adding an acid or alkali to the aqueous dispersion of colored resin particles. preferable. When a colloid of a poorly water-soluble inorganic hydroxide is used as the dispersion stabilizer, it is preferable to adjust the pH of the colored resin particle aqueous dispersion to 6.5 or less by adding an acid. As the acid to be added, inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid, and organic acids such as formic acid and acetic acid can be used. Particularly, since the removal efficiency is large and the burden on the manufacturing equipment is small, Sulfuric acid is preferred.

  Various known methods and the like can be used as the method of dehydration and filtration, and there is no particular limitation. Examples thereof include a centrifugal filtration method, a vacuum filtration method, and a pressure filtration method. Also, the drying method is not particularly limited, and various methods can be used.

(B) Pulverization method When the pulverization method is used to produce colored resin particles, the following process is performed.
First, a binder resin, a colorant, and other additives such as a charge control agent and a release agent added as necessary are mixed in a mixer, such as a ball mill, a V-type mixer, a Henschel mixer (trade name). Mix using a high-speed dissolver, internal mixer, Fallberg, etc. Next, the mixture obtained as described above is kneaded while being heated using a pressure kneader, a twin-screw extrusion kneader, a roller or the like. The obtained kneaded material is coarsely pulverized using a pulverizer such as a hammer mill, a cutter mill, or a roller mill. Furthermore, after finely pulverizing using a pulverizer such as a jet mill or a high-speed rotary pulverizer, it is classified into a desired particle size by a classifier such as an air classifier or an airflow classifier, and colored resin particles obtained by a pulverization method. Get.

  In addition, the binder resin used in the pulverization method, the colorant, and other additives such as a charge control agent and a release agent that are added as necessary are those mentioned in the above (A) suspension polymerization method. Can be used. Further, the colored resin particles obtained by the pulverization method can be made into core-shell type colored resin particles by a method such as an in situ polymerization method in the same manner as the colored resin particles obtained by the suspension polymerization method (A) described above.

  As the binder resin, other resins that have been widely used for toners can be used. Specific examples of the binder resin used in the pulverization method include polystyrene, styrene-butyl acrylate copolymer, polyester resin, and epoxy resin.

2. Colored resin particles Colored resin particles are obtained by a production method such as the above-described (A) suspension polymerization method or (B) pulverization method.
Hereinafter, the colored resin particles constituting the toner will be described. The colored resin particles described below include both core-shell type and non-core type.

  The volume average particle diameter (Dv) of the colored resin particles is preferably 4 to 12 μm, and more preferably 5 to 10 μm. When Dv is less than 4 μm, the fluidity of the polymerized toner is lowered, and transferability may be deteriorated or the image density may be lowered. When Dv exceeds 12 μm, the resolution of the image may decrease.

  The colored resin particles have a ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) of preferably 1.0 to 1.3, more preferably 1. 0-1.2. If Dv / Dn exceeds 1.3, transferability, image density, and resolution may decrease. The volume average particle diameter and the number average particle diameter of the colored resin particles can be measured using, for example, a particle size analyzer (trade name “Multisizer” manufactured by Beckman Coulter).

From the viewpoint of image reproducibility, the average circularity of the colored resin particles of the present invention is preferably 0.96 to 1.00, more preferably 0.97 to 1.00, and 0.98 to More preferably, it is 1.00.
When the average circularity of the colored resin particles is less than 0.96, the fine line reproducibility of printing may be deteriorated.

  In the present invention, the circularity is defined as a value obtained by dividing the circumference of a circle having the same projected area as the particle image by the projected image of the particle. The average circularity in the present invention is used as a simple method for quantitatively expressing the shape of the particles, and is an index indicating the degree of unevenness of the colored resin particles. The average circularity is determined by the colored resin particles. 1 is shown in the case of a perfect sphere, and the value becomes smaller as the surface shape of the colored resin particles becomes more complicated.

  The colored resin particles preferably exhibit positive chargeability. If negatively charged colored resin particles are used, the charge amount of the toner may be reduced and fogging may occur easily.

3. Production method of core-shell type composite fine particles Core-shell type composite fine particles (hereinafter sometimes simply referred to as “composite fine particles”) used as an external additive in the present invention are easily obtained by using resin fine particles as core particles. The diameter can be controlled, and the true specific gravity can be controlled to be low because it can be adjusted without firing by silica coating by a sol-gel method. Further, since the core particles are resin fine particles, the core particles are relatively soft and damage to the photoreceptor is reduced.

The core-shell type composite fine particles in which the surface of the resin fine particles used in the present invention is coated with silica may be i) a commercially available fine particle or ii) a commercially available resin fine particle coated with silica. Alternatively, iii) a resin fine particle produced by polymerization and coated with silica may be used.
The synthesis method of ii) is the same as the method of iii) except that the resin fine particles are synthesized by a polymerization reaction in the method of iii). Therefore, the method iii) will be specifically described below.

The resin fine particles can be obtained by pulverizing a polymerized monomer synthesized by bulk polymerization, or a polymer obtained by polymerizing a polymerizable monomer by solution polymerization and polymerizing the resulting solution. It can also be obtained by adding to a poor solvent, or it can be obtained by polymerizing a polymerizable monomer by emulsion polymerization. However, as will be described later, the number average particle diameter of the core-shell type composite fine particles is preferably in the range of 20 to 500 nm. Since composite fine particles in the range are easily obtained, it is preferable to obtain resin fine particles by emulsion polymerization.
For emulsion polymerization, conventionally known emulsion polymerization methods can be employed. In the emulsion polymerization, polymerization auxiliary materials such as emulsifiers, polymerization initiators, molecular weight modifiers and the like used in normal polymerization can be used.

  Examples of the resin used for the resin fine particles coated with silica in the present invention include polymers obtained by homopolymerizing or copolymerizing polymerizable monomers exemplified below. Examples of the polymerizable monomer include a monovinyl monomer and a crosslinkable polymerizable monomer. Monovinyl monomers include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-methoxy styrene, p-phenyl styrene, p-chloro styrene, and derivatives thereof; ethylene, propylene, butylene Ethylenically unsaturated monoolefins such as vinyl and isobutylene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl iodide; vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate; Methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth) acrylic acid-n-octyl, (meth) acrylic acid-2-ethylhexyl, (meth) acrylic acid dimethylaminoethyl, (meth) (Meth) acrylic acid such as diethylaminoethyl acrylate Ester ethers, vinyl methyl ether, vinyl ethyl ether, vinyl ethers such as vinyl isobutyl ether; acrylonitrile, methacrylonitrile, can be mentioned acrylic acid derivatives such as acrylamide.

  Examples of the crosslinkable polymerizable monomer include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof; carboxylic acids having two or more hydroxyl groups such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate. An ester compound in which two or more acids are ester-bonded; Other divinyl compounds such as N, N-divinylaniline and divinyl ether;

These monomers can be used alone or in combination of two or more. Among these, it is preferable to use a combination of a monovinyl monomer and a crosslinkable polymerizable monomer. By combining these, crosslinked resin fine particles can be obtained. Among the monovinyl monomers, styrene and its derivatives and (meth) acrylic acid esters are more preferable, styrene and its derivatives are more preferable, and styrene is particularly preferable. As the crosslinkable polymerizable monomer, an aromatic divinyl compound and an ester compound in which two or more (meth) acrylic acids are ester-bonded to an alcohol having two or more hydroxyl groups are more preferable, and an aromatic divinyl compound is more preferable. Divinylbenzene is particularly preferred.
The ratio of the monovinyl monomer and the crosslinkable monomer that is preferably used is such that the ratio of the crosslinkable monomer is 0.1 to 20% by mass of the total monomers, and 0.3 to 10%. It is more preferable that it is mass%, and it is still more preferable that it is 0.5-5 mass%.

The emulsifier used in the emulsion polymerization of latex is not limited to a specific emulsifier. Specific examples of the emulsifier include anionic emulsifiers such as alkyl benzene sulfonates, aliphatic sulfonates, sulfate esters of higher alcohols; polyethylene glycol alkyl ether type, polyethylene glycol alkyl ester type, polyethylene glycol alkyl phenyl ether type, etc. Nonionic emulsifier; amphoteric surfactant having carboxylate, sulfate ester, sulfonate, phosphate, phosphate ester salt, etc. as anion moiety, and amine salt, quaternary ammonium salt, etc. as cation moiety And so on.
The usage-amount of an emulsifier is 0.05-5 mass parts normally with respect to 100 mass parts of monomer whole quantity used for emulsion polymerization, Preferably it is 0.05-2 mass parts.

  The polymerization initiator used in latex emulsion polymerization is not limited to a specific polymerization initiator. Specific examples of the polymerization initiator include inorganic peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate, and hydrogen peroxide; t-butyl peroxide, cumene hydroperoxide, p-menthane hydro Peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, benzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, t- Organic peroxides such as butyl peroxyisobutyrate; azo compounds such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, methyl azobisisobutyrate. A preferred polymerization initiator is an inorganic peroxide. These polymerization initiators can be used alone or in combination of two or more. Redox polymerization initiators in which these polymerization initiators are combined with a reducing agent such as sodium sulfite can also be used.

  The usage-amount of a polymerization initiator is 0.1-5 mass parts normally with respect to 100 mass parts of monomer whole quantity used for emulsion polymerization, Preferably it is 0.5-3 mass parts. When emulsion polymerization is performed in multiple stages, even if the total amount of polymerization initiator to be used is added in the first stage, a part of the polymerization initiator to be used is added in the first stage, and the remainder is added in the second and subsequent stages. May be. The addition method of the polymerization initiator in each stage may be batch addition, continuous addition, or divided addition.

At the time of emulsion polymerization of latex, auxiliary materials such as a molecular weight regulator, a dispersant, a chelating agent and the like that are usually used in emulsion polymerization can be added. The type and amount of the secondary material are not limited. When the emulsion polymerization is performed in a plurality of stages, the addition timing and addition method of the auxiliary material to be used are not limited as necessary.
Specific examples of the molecular weight modifier include: α-methylstyrene dimer; mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan, octyl mercaptan; halogenated hydrocarbons such as carbon tetrachloride, methylene chloride, methylene bromide; tetraethylthiuram Sulfur-containing compounds such as disulfide, dipentamethylene thiuram disulfide and diisopropylxanthogen disulfide. These molecular weight modifiers can be used alone or in combination of two or more.

  The polymerization temperature at each stage during the emulsion polymerization of the latex is not limited to a specific range. The said polymerization temperature is 5-95 degreeC normally, Preferably it is 50-95 degreeC. The polymerization temperature at each stage may be different, and the polymerization temperature during the emulsion polymerization at each stage may change.

  The number average particle diameter of the resin fine particles is preferably 12 to 410 nm, and more preferably 30 to 165 nm. This is because the number average particle diameter of the composite fine particles described later is preferably 20 to 500 nm.

  The method of covering the resin fine particles with the continuous layer of silica in the present invention can be achieved by using a silica coating technique using a sol-gel method. Specifically, the silica coating by the sol-gel method is performed by the following method. After dispersing fine resin particles as a base in water and / or an aqueous medium in which silane alkoxide is dissolved, the dispersion is dropped into water and / or an aqueous medium to which alkali is added, or Water or an aqueous medium to which alkali has been added is added dropwise to the dispersion solution. According to this method, the silane alkoxide dissolved in the dispersion containing the fine resin particles undergoes hydrolysis and polycondensation in the presence of alkali, and gradually insolubilizes. It is deposited on the surface of the resin fine particles due to the interaction. As a result, a coating layer is formed on the surface of the resin fine particles by adhering the granular lumps containing silica. In this method, in order to selectively coat the silica fine particles on the surface of the resin fine particles, the base resin fine particles are dispersed in water and / or an aqueous medium in which silane alkoxide is dissolved, and then stirred. If necessary, the resin fine particles may be dispersed in a medium in which the silane alkoxide is dissolved by applying heat.

  Here, the resin fine particles used for producing the core-shell type composite fine particles having the surface of the resin fine particles coated with silica are preferably produced by an emulsion polymerization method as described above, followed by silica. The coating by may be performed by washing the resin fine particles, filtering and drying, dispersing the dried resin fine particles in a solvent, and using the sol-gel method. Preferably it is done.

  Examples of the silane alkoxide used above include the following. Examples of the bifunctional or higher alkoxide include tetramethoxysilane, methyltriethoxysilane, hexyltriethoxysilane, triethoxychlorosilane, di-t-butoxydiacetoxysilane, hydroxymethyltriethoxysilane, tetraethoxysilane, and tetra-n. -Propoxysilane, tetrakis (2-methacryloxyethoxysilyl) silane, allyltriethoxysilane, allyltrimethoxysilane, 3-aminopropyltriethoxysilane, bis (triethoxysilyl) ethylene, bis (triethoxysilyl) methane, bis (Triethoxysilyl) 1,7-octadiene, 2,2- (chloromethyl) allyltrimethoxysilane, ((chloromethyl) phenylethyl) trimethoxysilane, 1,3-divinyltetraethoxy Siloxane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, (3-glycidoxypropyl) methyldiethoxysilane, (3-glycidoxypropyl) methyldimethoxysilane, (3-glycidoxypropyl) Trimethoxysilane, 3-mercaptopropyltriethoxysilane, methacrylamidepropyltriethoxysilane, methacryloxymethyltriethoxysilane, methacryloxymethyltrimethoxysilane, 7-octenyltrimethoxysilane, vinylmethyldiethoxysilane, vinylmethyldimethoxy Silane, vinyltriethoxysilane, vinyltriphenoxysilane, etc. are mentioned. Among these, tetrafunctional silane alkoxides such as tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, and tetrakis (2-methacryloxyethoxysilyl) silane are preferably used as essential components.

  Examples of the monofunctional silane alkoxide that can be used in combination with the above-mentioned bifunctional or higher silane alkoxide include (3-acryloxypropyl) dimethylmethoxysilane, o-acryloxy (polyethyleneoxy) trimethylsilane, acrylic Loxytrimethylsilane, 1,3-bis (methacryloxy) -2-trimethylsiloxypropane-3-chloro-2-trimethylsiloxypropene, (cyclohexenyloxy) trimethylsilane, methacryloxyethoxytrimethylsilane, (methacryloxymethyl) dimethylethoxy Silane etc. are mentioned. These silane alkoxides may be used alone or in combination of two or more.

  As the aqueous medium used in the sol-gel reaction, for example, alcohols such as methanol, ethanol, and isopropanol are used. When the organic nature of these solvents increases, the solubility of the polycondensate of silane alkoxide increases, and the toner Silane alkoxide polycondensate is difficult to deposit on the particle surface. Therefore, it is preferable to use methanol or ethanol as the aqueous medium.

In addition, it is preferable that the surface of the core-shell type composite fine particles is subjected to a hydrophobization treatment so that the core-shell type composite fine particles prepared by the above method have a stable effect even under high temperature and high humidity. Either a positively chargeable treatment agent or a negatively chargeable treatment agent can be used as the hydrophobic treatment agent, but in the present invention, it is preferable to use a positively chargeable hydrophobic treatment agent. As the hydrophobizing agent, for example, a silane coupling agent, silicone oil, or the like can be used.
Examples of the silane coupling agent include disilazane such as hexamethyldisilazane; cyclic silazane; trimethylsilane; trimethylchlorosilane; dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, benzyldimethylchlorosilane, and methyltrimethoxysilane. , Methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-octadecyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxy Alkylsilane compounds such as silane, γ-methacryloxypropyltrimethoxysilane, and vinyltriacetoxysilane, and γ- Aminopropyltriethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N- (2 -Aminoethyl) 3-aminopropyltrimethoxysilane, and aminosilane compounds such as N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane; These can be used alone or in combination of two or more.
Examples of the silicone oil include dimethylpolysiloxane, methylhydrogenpolysiloxane, methylphenylpolysiloxane, and amino-modified silicone oil. These can be used alone or in combination of two or more.
Among the above, the hydrophobizing agent may be contained alone or in combination of two or more, and when a silane coupling agent or silicone oil is used, the resulting toner is more preferable because it provides high image quality. .

As a method for hydrophobizing the composite fine particles used as an external additive in the present invention, a general method can be used, and examples thereof include a wet method and a dry method.
Specifically, a method of dripping or spraying the hydrophobizing agent while the composite fine particles used as an external additive are stirred at high speed (dry method), and hydrophobizing by dissolving the hydrophobizing agent in an organic solvent Examples thereof include a method of adding composite fine particles while stirring an organic solvent containing a treatment agent (wet method). The wet method is preferable because the composite fine particles can be uniformly hydrophobized.

When the wet method is used, the reaction liquid obtained by adding an organic solvent containing a hydrophobizing agent is used as it is while stirring the reaction liquid of the core-shell composite fine particles obtained by the sol-gel reaction. On the contrary, the reaction liquid obtained by adding the reaction liquid of the core-shell type composite fine particles obtained by the sol-gel reaction while stirring the organic solvent containing the hydrophobizing agent can be used. It can also be used as it is for hydrophobic treatment.
However, in the wet method, the core-shell type composite fine particles obtained by the sol-gel reaction are washed, filtered, and dried, and then the core-shell type composite fine particles are dispersed in an organic solvent and the hydrophobization treatment agent is contacted. Is preferred. The core-shell type composite fine particles dispersed in the organic solvent obtained by this preferred method are used after removing the organic solvent by distillation under reduced pressure, drying, and crushing if necessary.

4). Core-shell type composite fine particles Core-shell type composite fine particles are obtained by the above-described production method. Hereinafter, the core-shell type composite fine particles used as the external additive of the present invention will be described.

The core-shell type composite fine particles used as an external additive in the present invention are core-shell type composite fine particles in which the surface of the resin fine particles is coated with silica. In addition, when the total volume of the core-shell type composite fine particles is 100% by volume, the volume ratio of the silica component of the composite fine particles is 45 to 75% by volume.
When the volume ratio is less than 45% by volume, the fluidity of the toner, which will be described later, may be reduced. On the other hand, when the volume ratio exceeds 75% by volume, the environmental stability of the toner, which will be described later, is deteriorated, and the fogging of the toner in a high temperature and high humidity environment may be deteriorated.
When the total volume of the core-shell type composite fine particles is 100% by volume, the volume ratio of the silica component of the composite fine particles is more preferably 50 to 70% by volume, and still more preferably 55 to 70% by volume.

  In the present invention, the volume ratio of the silica component of the core-shell composite fine particles is the ratio of the volume of the coated silica to the total volume of the core-shell composite fine particles. The ratio is the ratio of the increase in the volume of the resin fine particles as the raw material to the volume of the core-shell composite fine particles with respect to the total volume of the core-shell composite fine particles, and the number average particle diameter of the resin fine particles and the core-shell composite fine particles It can be calculated from the number average particle diameter of

When it is unclear whether or not the fine particles are core-shell composite fine particles, when calculating the volume ratio of the silica component of the fine particles, for example, the following method can be employed.
First, using atomic absorption spectrometry or the like, it is confirmed whether or not the fine particles contain silicon. This makes it possible to predict that the fine particles are oxides such as silica.
When it is found that the fine particles contain silicon, the number average particle diameter of the fine particles is measured in the same manner as described above. Subsequently, the fine particles are put into hydrofluoric acid, silica is dissolved, washed with water and dried, and the number average particle diameter of the resin fine particles as the core is measured in the same manner as described above. The volume ratio of the silica component of the fine particles can be calculated from the values of the two number average particle diameters before and after silica dissolution measured in this way.

The adsorbed water content of the core-shell type composite fine particles is preferably 0.5 to 1.5% by mass. When the amount of adsorbed moisture is less than 0.5% by mass or when the amount of adsorbed moisture exceeds 1.5% by mass, the environmental stability of the toner described later deteriorates and the high-temperature and high-humidity of the toner deteriorates. There is a risk of fogging in the environment.
The adsorbed water content of the core-shell type composite fine particles is more preferably 0.5 to 1.4% by mass, and further preferably 0.6 to 1.2% by mass.

It is preferable that the core-shell type composite fine particles exhibit positive chargeability. When the negatively chargeable core-shell type composite fine particles are used, there is a possibility that the charge amount of the toner is lowered and fogging is likely to occur.
The value of the blow-off charge amount of the core-shell type composite fine particles is preferably +1000 to +4000 μC / g. When the value is less than +1000 μC / g, the charge amount of the toner may be reduced and fog may be easily generated. On the other hand, when the value exceeds +4000 μC / g, it is difficult to prepare the core-shell composite fine particles.
The value of the blow-off charge amount of the core-shell type composite fine particles is more preferably +1500 to +3000 μC / g, and further preferably +1700 to +2500 μC / g.

The number average particle size of the core-shell type composite fine particles is preferably 20 to 500 nm. When the number average particle size is less than 20 nm, the charge amount of the toner may be reduced and fog may be easily generated. On the other hand, when the number average particle diameter exceeds 500 nm, the environmental stability of the toner described later may deteriorate, and the fogging of the toner in a high temperature and high humidity environment may deteriorate.
The number average particle diameter of the core-shell type composite fine particles is more preferably 25 to 400 nm, still more preferably 30 to 300 nm, and particularly preferably 50 to 200 nm.

5. Production method of toner of the present invention The toner of the present invention is prepared by mixing and stirring the colored resin particles together with the core-shell composite fine particles, and suitably attaching and externally adding the core-shell composite fine particles to the surface of the colored resin particles. Can be obtained.

The addition amount of the core-shell type composite fine particles is usually 0.1 to 20 parts by mass with respect to 100 parts by mass of the colored resin particles. When the addition amount of the core-shell type composite fine particles is less than 0.1 parts by mass with respect to 100 parts by mass of the colored resin particles, the effect of the present invention is not sufficiently exhibited. On the other hand, when the addition amount of the core-shell type composite fine particles exceeds 20 parts by mass with respect to 100 parts by mass of the colored resin particles, the charge amount of the toner may be lowered.
The addition amount of the core-shell type composite fine particles is preferably 0.2 to 10 parts by mass, more preferably 0.3 to 5 parts by mass, and still more preferably 0.5 to 2 parts by mass with respect to 100 parts by mass of the colored resin particles.

  The method for adhering and adding (external addition) the core-shell type composite fine particles to the surface of the colored resin particles is not particularly limited. , Kawada Seisakusho Co., Ltd.), Q mixer (: trade name, manufactured by Mitsui Mining Co., Ltd.), Mechano Fusion System (: trade name, manufactured by Hosokawa Micron Corporation), and Mechano Mill (: trade name, manufactured by Okada Seiko Co., Ltd.) Can be performed using an apparatus capable of.

Other external additives may be mixed with the core-shell type composite fine particles.
Examples of the other external additives include inorganic fine particles made of silica, titanium oxide, aluminum oxide, zinc oxide, tin oxide, calcium carbonate, calcium phosphate, and / or cerium oxide; polymethyl methacrylate resin, silicone resin, and And / or organic fine particles comprising melamine resin and the like. Among these, inorganic fine particles are preferable, and among inorganic fine particles, silica and / or titanium oxide are preferable, and fine particles made of silica are particularly preferable.
In addition, the said other external additive used together with a core-shell type composite microparticle may be only one type, and may be two or more types.

When the core-shell type composite fine particles are used in combination with another external additive, the number average particle diameter of the other external additive is preferably 7 to 300 nm. When the number average particle diameter of the other external additive is less than 7 nm, the other external additive is easily embedded from the surface of the colored resin particles to the inside, and the fluidity is sufficiently sufficient for the toner particles. In some cases, it cannot be applied, and the printing performance may be adversely affected. On the other hand, when the number average particle diameter of the other external additive exceeds 300 nm, the ratio (coverage) of the other external additive to the surface of the toner particles decreases, so that the fluidity May not be sufficiently imparted to the toner particles, which may adversely affect printing performance.
The number average particle diameter of the other external additive is more preferably 15 to 80 nm.

6). Toner according to the present invention The toner according to the present invention obtained through the above-described steps is obtained by using core-shell type composite fine particles in which the surface of resin fine particles is coated with silica as an external additive. Even if it is applied to particles and continuous printing is performed on a large number of sheets, it is an electrostatic charge image developing toner that hardly deteriorates in image quality due to fog or the like and has excellent fluidity.

The toner of the present invention preferably has a fluidity value of 80 to 100 as measured by the method described below. The fluidity as used herein is a value expressed as a percentage of the ratio of the toner passing through the sieve to the total mass of the toner.
The toner of the present invention preferably has a fluidity value of 82 to 100, and more preferably 85 to 100.

The following method can be illustrated as an example of measurement of fluidity. First, a sieve having a predetermined amount of openings is prepared. At this time, two or more types of sieves may be used. In addition, when using two or more types of sieves, the sieves are overlapped from the top in the descending order of openings.
Next, a predetermined amount of the toner sample to be measured is placed on the sieve. When two or more types of sieves are used, the toner sample is placed on the sieve that is stacked on top, that is, the sieve having the largest opening.
Subsequently, using a powder measuring machine, the sieve is vibrated for a certain period of time under constant vibration conditions, and then the mass of the toner remaining on the sieve is measured. When two or more types of sieves are used, the remaining toner mass is measured for each sieve.
Finally, the ratio of the mass of the toner remaining on the sieve to the total mass of the toner is calculated. The fluidity value is a value that is calculated based on the ratio and expresses the ratio of the toner that has passed through the sieve to the total mass of the toner as a percentage. When two or more types of sieves are used, after calculating the ratio of the mass of toner remaining on the sieve for all sieves, the ratios are added together to calculate the fluidity value. In this case, a coefficient of 1 or less may be assigned to each sieve, and the product of the ratio of the mass of toner remaining on the sieve and the coefficient may be added up. For example, when two types of sieves are used, it is assumed that a coefficient 1 is assigned to the sieve A having the largest opening, and a coefficient 0.6 is assigned to the sieve B having the smallest opening. In this case, the sum of the product of the toner mass ratio α remaining on the sieve A and the coefficient 1 and the product of the toner mass ratio β remaining on the sieve B and the coefficient 0.6. Based on (α + 0.6β), fluidity is calculated. As described above, the fluidity of the toner can be more accurately evaluated by appropriately assigning coefficients.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited only to these examples. Parts and% are based on mass unless otherwise specified.
The test methods performed in the examples and comparative examples are as follows.

1. Production of core-shell composite fine particles [Production Example 1]
In a container equipped with a stirrer substituted with nitrogen, 3 parts of soft dodecylbenzenesulfonic acid was dissolved in 150 parts of ion-exchanged water, and then 95 parts of styrene was emulsified to prepare a polymerizable monomer emulsion. After raising the temperature of the emulsion to 80 ° C., 0.6 part of potassium persulfate dissolved in 10 parts of ion exchange water was added and polymerized for 2 hours. Subsequently, after the reactor temperature was lowered to 40 ° C., 5 parts of divinylbenzene was added and stirred for 2 hours, and then the temperature was raised to 85 ° C. and potassium persulfate dissolved in 2 parts of water 0.1 The polymerization reaction was carried out for 4 hours by adding a portion, and an aqueous hydroquinone solution was added as a reaction terminator to complete the polymerization. The polymerization conversion rate at this time was 99%. Water soluble material was removed by ultrafiltration. By adjusting the pH and concentration of the emulsion, a resin fine particle emulsion having a solid content concentration of 50% and a pH of 8.5 was obtained. A part of this emulsion was dried and subjected to measurement of the number average particle diameter of resin fine particles described later.

After 200 parts of the obtained emulsion (100 parts in terms of solid content) was added to 10,000 parts of methanol, 600 parts of tetraethoxysilane and 150 parts of 1-methyltriethoxysilane were dissolved as silicon compounds. In this state, the mixture was heated to 50 ° C. and stirred for 1 hour to disperse the resin fine particles in a medium in which silane alkoxide was dissolved. Next, 20 parts by weight of 28 mass% NH ₄ OH aqueous solution was added dropwise to this solution, and the mixture was stirred at room temperature for 48 hours to carry out a sol-gel reaction, thereby coating the surface of the resin fine particles with silica.

  After completion of the reaction, the obtained particles were washed with ion-exchanged water, then washed with methanol, the particles were filtered, and dried at 45 ° C. for 24 hours under a reduced pressure of 40 kPa, whereby the surface of the resin fine particles was Core-shell type composite fine particles 1 coated with silica were obtained. A part of the core-shell type composite fine particles 1 was subjected to measurement of the number average particle size of the core-shell type composite fine particles described later.

  100 g of the core-shell type composite fine particles 1 are dispersed in 600 g of toluene, and 14% by mass of 3-aminopropyltriethoxysilane (a silicon compound containing an amino group) is added to 100% by mass of silica contained in the fine particles 1. After 1 part was added, the mixture was dispersed and mixed for 15 minutes to contact the fine particles. Next, after adding 1 part of 14% by mass of trifluoropropyltrimethoxysilane (a silicon compound containing no amino group) to the fine particles, the fine particles were dispersed and mixed for 15 minutes to contact the fine particles. The dispersion was distilled under reduced pressure, dried and pulverized to obtain core-shell type composite fine particles A that were hydrophobized to be positively charged. There was no change in particle size due to the hydrophobization treatment.

[Production Example 2]
In the production example 1, the amount of soft dodecylbenzenesulfonic acid added was changed from 3 parts to 8 parts, and as a result of polymerization, a resin particle emulsion having a number average particle diameter of 50 nm was obtained, and the core-shell type composite fine particles were Similar to Production Example 1 above, except that the amount of tetraethoxysilane added was changed from 600 parts to 700 parts and the amount of 1-methyltriethoxysilane added was changed from 150 parts to 200 parts when manufacturing. Thus, core-shell type composite fine particles B were produced.

[Production Example 3]
Core-shell composite fine particles C were produced in the same manner as in Production Example 1 except that the sol-gel reaction time was changed from 48 hours to 72 hours in Production Example 1.

[Production Example 4]
In the production example 1, as a result of polymerization by changing the addition amount of soft-type dodecylbenzenesulfonic acid from 3 parts to 0.8 parts, a resin particle emulsion having a number average particle size of 150 nm was obtained, and the core-shell type composite When the fine particles were produced, the amount of tetraethoxysilane added was changed from 600 parts to 500 parts, and the amount of 1-methyltriethoxysilane added was changed from 150 parts to 120 parts. Similarly, core-shell composite fine particles D were produced.

[Production Example 5]
In the above Production Example 1, the polymerizable monomer used in the first polymerization was changed from 95 parts of styrene and 5 parts of divinylbenzene to 100 parts of styrene, except that 5 parts of divinylbenzene added later was not used. Core-shell composite fine particles E were produced in the same manner as in Production Example 1 above.

[Production Example 6]
Acrylic / styrene resin fine particles (manufactured by Soken Chemical Co., Ltd., trade name: MP-5500, number average particle size 400 nm) 1.0 part by mass are dispersed in 100 parts by mass of methanol, and then 20 parts by mass as a silicon compound. Of tetraethoxysilane and 5.0 parts by mass of methyltriethoxysilane were dissolved. In this state, the mixture was heated to 50 ° C. and stirred for 1 hour to disperse the resin fine particles in a medium in which silane alkoxide was dissolved. Next, 20 parts by mass of a 28% by mass aqueous NH ₄ OH solution was added dropwise to this solution, and the mixture was stirred at room temperature for 48 hours to carry out a sol-gel reaction to coat the surface of the resin fine particles with silica. .
After the completion of the reaction, the obtained particles were washed with purified water and then washed with methanol, and then the particles were filtered and dried to produce core-shell type composite fine particles F coated with resin particles on silica.

[Production Example 7]
1.0 part by mass of acrylic / styrene resin fine particles (manufactured by Soken Chemical Co., Ltd., trade name: MP-5500, number average particle size 400 nm) of Production Example 6 was added to acrylic / styrene resin fine particles (Soken Chemical Co., Ltd.). (Product name: MP-1450, number average particle size 250 nm) Core-shell composite fine particles G were produced in the same manner as in Production Example 6 except that the content was changed to 1.0 part by mass.

2. Evaluation of Physical Properties of Composite Fine Particles Core-shell type composite fine particles A to G obtained from Production Examples 1 to 7, Hydrophobized silica fine particles (manufactured by Clariant, trade name: H05TA. Hereinafter, sometimes referred to as silica fine particles A) ) And hydrophobized silica fine particles (trade name: TG-C321, manufactured by Cabot Inc .; hereinafter, sometimes referred to as silica fine particles B). Was measured. For the core-shell type composite fine particles A to G, the number average particle diameter of the resin fine particles as the raw material of these composite fine particles was also measured, and the ratio of the silica component of the core-shell type composite fine particles was calculated.

2-1. Measurement of the number average particle size of the core-shell type composite fine particles and the like and the resin fine particles as the raw material The number average particle size of the core shell type composite fine particles and the like and the resin fine particles as the raw material were measured by the following method. That is, for each of these fine particles, a field emission scanning electron microscope (manufactured by Hitachi, Ltd., product name: S-4700) is used to take a photograph at a magnification of 10,000 times, and the photograph is taken as an image processing analyzer. (The product name: Luzex IID, manufactured by Nireco) calculates the equivalent circle diameter corresponding to the projected area of the fine particles for each particle under the conditions of the particle area ratio to the frame area: 2% at the maximum and the total number of treated particles: 100. The average value was obtained.

2-2. Calculation of ratio of silica component of core-shell type composite fine particles For the core-shell type composite fine particles A to G, the ratio of the volume of the coated silica to the total volume of the core-shell type composite fine particles was calculated based on the following formula.
Percent of silica component] = [{(4/3) π (r 2/2) 3 - (4/3) π (r 1/2) 3} / {(4/3) π (r 2/2 ) ³ }] × 100 = {(r ₂ ³ −r ₁ ³ ) / (r ₂ ³ )} × 100
(In the above formula, r ₁ is the number average particle diameter of the resin fine particles as the core, and r ₂ is the number average particle diameter of the core-shell composite fine particles.)

2-3. Measurement of Adsorbed Moisture Content A moisture adsorption / desorption measuring device (manufactured by HEIDEN Co., Ltd., trade name: IGAsorb) was used for measuring the adsorbed water content. In the apparatus, the core-shell type composite fine particles, which are samples, are allowed to stand for 1 hour in a dry nitrogen stream, and then the dry mass of the sample is measured. The mass of the sample adsorbed and adsorbed with water was measured.
The amount of adsorbed water (% by mass) was calculated from {(mass of sample adsorbed with water−mass of dried sample) / mass of dried sample)} × 100.

2-4. Measurement of charge amount Carrier (Powder Tech Co., Ltd., trade name “F96-80”) 9.95 g and 0.05 g of sample are weighed and put into a glass bottle with a capacity of 100 cc, 30 minutes at 150 rpm. After rotating, using a blow-off meter (trade name “TB-203” manufactured by Toshiba Chemical Corporation), the blow-off charge amount was measured by blowing at a pressure of 4.5 kPa nitrogen gas and sucking at a pressure of 9.5 kPa. .
The measurement was performed in an environment at a temperature of 23 ° C. and a relative humidity of 50%. The charge polarity of the external additive can be determined by measuring the blow-off charge amount.
Frictional charge amount (μC / g) = charge amount of measurement sample mixture (μC) / (mass of measurement sample compound (g) × concentration of measurement sample (mass%))

  Table 1 shows the results of measurement of the amount of adsorbed water, the chargeability and the charge amount of the core-shell type composite fine particles A to G and the silica fine particles A and B together with the structure data of each external additive particle. In the following table, “external additive (A)” refers to core-shell type composite fine particles A to G and silica fine particles A and B.

3. 3. Production of colored resin particles and evaluation of physical properties 3-1. Preparation of polymerizable monomer composition for core 83 parts of styrene and 17 parts of n-butyl acrylate as monovinyl monomers, 7 parts of carbon black (trade name: # 25B, manufactured by Mitsubishi Chemical Corporation) as a black colorant, charge control 1 part of a positively chargeable charge control resin (product name: FCA-207P, quaternary ammonium base-containing styrene / acrylic resin) as an agent, 0.6 part of divinylbenzene as a crosslinkable polymerizable monomer 1.9 parts of t-dodecyl mercaptan as a molecular weight modifier, and 0.25 parts of a polymethacrylate macromonomer (manufactured by Toa Gosei Co., Ltd., trade name: AA6, Tg = 94 ° C. of the resulting polymer) as a macromonomer. After stirring and mixing with a stirrer, the mixture was further dispersed uniformly using a media type dispersing machine. Here, 5 parts of dipentaerythritol hexamyristate was added, mixed and dissolved as a release agent to obtain a polymerizable monomer composition.

3-2. Preparation of Aqueous Dispersion Medium On the other hand, at room temperature, in an aqueous solution in which 10.2 parts of magnesium chloride (water-soluble polyvalent metal salt) is dissolved in 250 parts of ion-exchanged water, sodium hydroxide (alkali hydroxide) is added to 50 parts of ion-exchanged water. An aqueous solution in which 6.2 parts of the metal was dissolved was gradually added under stirring to prepare a magnesium hydroxide colloid (slightly water-soluble metal hydroxide colloid) dispersion.

3-3. Granulation step The polymerizable monomer composition was charged into the magnesium hydroxide colloid dispersion at room temperature and stirred. After adding 6 parts of t-butyl peroxy-2-ethylhexanoate (Nippon Yushi Co., Ltd., trade name: Perbutyl O) as a polymerization initiator, an in-line type emulsifier / disperser (trade name, manufactured by Ebara Corporation) is added. : Ebara Milder) was dispersed by high-speed shearing and stirring at a rotational speed of 15,000 rpm for 10 minutes to form droplets of the polymerizable monomer composition.

3-4. Suspension polymerization step A suspension (polymerizable monomer composition dispersion) in which droplets of the above polymerizable monomer composition are dispersed is charged into a reactor equipped with a stirring blade and heated to 90 ° C. Warm to initiate the polymerization reaction. When the polymerization conversion reached almost 100%, 2,2′-azobis (shell polymerization initiator dissolved in 1 part of methyl methacrylate and 10 parts of ion-exchanged water as shell polymerizable monomer) 0.3 part of 2-methyl-N- (2-hydroxyethyl) -propionamide) (manufactured by Wako Pure Chemical Industries, Ltd., trade name: VA-086, water-soluble) was added, and the reaction was continued at 90 ° C. for 4 hours. Thereafter, the reaction was stopped by cooling with water to obtain an aqueous dispersion of colored resin particles having a core-shell structure.

3-5. Post-treatment step The aqueous dispersion of the colored resin particles was added dropwise with stirring sulfuric acid at room temperature, and acid washing was performed until the pH was 6.5 or less. Subsequently, filtration separation was performed, 500 parts of ion-exchanged water was added to the obtained solid content to make a slurry again, and water washing treatment (washing, filtration, dehydration) was repeated several times. Next, filtration separation was performed, and the obtained solid content was put in a container of a dryer and dried at 45 ° C. for 48 hours to obtain dried colored resin particles.

The obtained colored resin particles were measured for volume average particle diameter (Dv) and particle diameter distribution (Dv / Dn).
About 0.1 g of a measurement sample (colored resin particles) was weighed and taken in a beaker, and 0.1 mL of an alkylbenzenesulfonic acid aqueous solution (trade name: Drywell, manufactured by Fuji Film Co., Ltd.) was added as a dispersant. Add 10-30 mL of Isoton II to the beaker and disperse with a 20 W ultrasonic disperser for 3 minutes. Then, use a particle size analyzer (trade name: Multisizer, manufactured by Beckman Coulter, Inc.) to determine the aperture diameter. Measuring the volume average particle diameter (Dv) and the number average particle diameter (Dn) of the colored resin particles under the condition of 100 μm, the number of measured particles; 100,000, and calculating the particle diameter distribution (Dv / Dn) did. As a result, the obtained colored resin particles had a volume average particle diameter (Dv) of 9.7 μm and a particle diameter distribution (Dv / Dn) of 1.14.

The average circularity of the obtained colored resin particles was calculated.
First, 10 mL of ion-exchanged water is put in a container in advance, and 0.2 mL of an alkylbenzene sulfonic acid aqueous solution (manufactured by Fujifilm, trade name: Drywell) is added as a dispersant therein, and 0.2 g of colored resin particles are further added. In addition, 60 W (Watt) was applied for 3 minutes with an ultrasonic disperser. The concentration of the colored resin particles at the time of measurement is adjusted to 3,000 to 10,000 particles / μL, and 1,000 to 10,000 colored resin particles having an equivalent circle diameter of 0.4 μm or more are flow-type particle images. Measurement was performed using an analyzer (trade name: FPIA-2100, manufactured by Simex Corporation). When the average circularity was determined from the measured value, the average circularity of the obtained colored resin particles was 0.987.

4). Manufacture of toner for developing electrostatic charge image As described in the section of “3. Production and evaluation of physical properties of colored resin particles” and the like described above in “1. Production of core-shell type composite fine particles” A toner for developing an electrostatic image was produced using the colored resin particles.

[Example 1]
To 100 parts of the colored resin particles, 1.2 parts of the core-shell type composite fine particles A produced in Production Example 1 above, and silica fine particles having a number average primary particle size of 22 nm that have been hydrophobized (trade name: manufactured by Cabot Corporation) 0.8 parts of TG-7120) was added, and the mixture was stirred for 5 minutes at a peripheral speed of 40 m / s using an FM mixer (trade name: FM-10, manufactured by Nippon Coke Co., Ltd.). The toner for developing an electrostatic charge image of Example 1 was obtained.

[Example 2]
The electrostatic charge image developing toner of Example 2 in the same manner as in Example 1 except that the core-shell type composite fine particles A produced in Production Example 1 were changed to the core-shell type composite fine particles B produced in Production Example 2 above. Got.

[Example 3]
The electrostatic charge image developing toner of Example 3 in the same manner as in Example 1 except that the core-shell type composite fine particles A produced in Production Example 1 were changed to the core-shell type composite fine particles C produced in Production Example 3 above. Got.

[Example 4]
The electrostatic charge image developing toner of Example 4 in the same manner as in Example 1 except that the core-shell type composite fine particles A produced in Production Example 1 were changed to the core-shell type composite fine particles D produced in Production Example 4 above. Got.

[Example 5]
The electrostatic charge image developing toner of Example 5 in the same manner as in Example 1 except that the core-shell type composite fine particles A produced in Production Example 1 were changed to the core-shell type composite fine particles E produced in Production Example 5 above. Got.

[Comparative Example 1]
A toner for developing an electrostatic charge image of Comparative Example 1 was obtained in the same manner as in Example 1 except that the core-shell type composite fine particles A produced in Production Example 1 were changed to silica fine particles A.

[Comparative Example 2]
A toner for developing an electrostatic charge image of Comparative Example 2 was obtained in the same manner as in Example 1 except that the core-shell type composite fine particles A produced in Production Example 1 were changed to silica fine particles B.

[Comparative Example 3]
A toner for developing an electrostatic charge image of Comparative Example 3 in the same manner as in Example 1 except that the core-shell type composite fine particles A produced in Production Example 1 are changed to the core-shell type composite fine particles F produced in Production Example 6 above. Got.

[Comparative Example 4]
A toner for developing an electrostatic charge image of Comparative Example 4 in the same manner as in Example 1 except that the core-shell type composite fine particles A produced in Production Example 1 are changed to the core-shell type composite fine particles G produced in Production Example 7 above. Got.

5. Evaluation of electrostatic charge image developing toner For the electrostatic charge image developing toners of Examples 1 to 5 and Comparative Examples 1 to 4, fluidity evaluation was performed in a room temperature and normal humidity (N / N) environment or at high temperature and high humidity (H / H) Measurement of toner charge amount under environment, fog evaluation under normal temperature and normal humidity (N / N) environment or high temperature and high humidity (H / H) environment, and printing durability test were performed.

5-1. Evaluation of fluidity Three types of sieves having openings of 150 μm, 75 μm, and 45 μm are stacked in this order from the top, and 4 g of the toner for developing an electrostatic charge image to be measured is precisely placed on the top of the sieve having an opening of 150 μm. Weighed and placed. Next, these three types of sieves were vibrated for 15 seconds under the condition of vibration intensity scale 4 using a powder measuring machine (trade name: powder tester manufactured by Hosokawa Micron Co., Ltd.), and then remained on each sieve. The mass of the electrostatic image developing toner was measured. Each measured value was substituted into the following formulas (1) to (3) to obtain values of a, b, and c. The values of a, b, and c were substituted into Equation (4) to calculate the fluidity value. Each sample was measured three times, and the average value was obtained.
a = [(mass of polymer remaining on the 150 μm sieve (g)) / 4 g] × 100 Formula (1)
b = [(mass of polymer remaining on 75 μm sieve (g)) / 4 g] × 100 × 0.6 Formula (2)
c = [(the mass of the polymer remaining on the 45 μm sieve (g)) / 4 g] × 100 × 0.2 Formula (3)
Fluidity = 100− (a + b + c) Formula (4)

5-2. Measurement of toner charge amount under normal temperature and normal humidity (N / N) environment A commercially available non-magnetic one-component developing type printer (HL-3040CN) was used. After the toner cartridge of the developing device is filled with toner, one sheet of solid white printing is performed, and an electrometer (manufactured by Advantest, product name: TR8652) is used in a normal temperature and normal humidity (N / N) environment (temperature: 23 ° C., The toner on the developing roll was collected at a humidity of 50%, and the charge amount was measured. The toner charge amount was calculated by dividing the measured charge amount value by the weight of the collected toner.
(Measured charge amount (μC) / collected toner weight (g)) = toner charge amount (μC / g)

5-3. Measurement of toner charge amount under high temperature and high humidity (H / H) environment After toner is charged in the toner cartridge of the developing device, under high temperature and high humidity (H / H) environment (temperature: 35 ° C, humidity: 80%) The toner charge amount was calculated in the same manner as the normal temperature and normal humidity charge amount except that the charge amount was measured in the environment after being left for 24 hours.

5-4. Fog evaluation under normal temperature and normal humidity (N / N) environment A commercially available non-magnetic one-component developing type printer (HL-3040CN) was used. The toner cartridge of the developing device was filled with toner, and then left in a normal temperature and normal humidity (N / N) environment (temperature: 23 ° C., humidity: 50%) for 24 hours. After leaving, one sheet of solid white printing was performed and visually checked for fog. Then, the whiteness on the paper surface of the white printed matter was measured using the whiteness meter (made by Nippon Denshoku).
{(Whiteness before printing) − (Whiteness of white printed matter)} = fogging density was calculated.

5-5. Fog evaluation under high-temperature and high-humidity (H / H) environment After toner is filled in the toner cartridge of the developing device, the high-temperature and high-humidity (H / H) environment (temperature: 35 ° C., humidity: 80%) is used for 24 hours. The fog density was calculated in the same manner as in the normal temperature and normal humidity fog evaluation except that the fog was measured under the environment.

5-6. Print durability test
For the printing durability test, a commercially available non-magnetic one-component developing type printer (HL-3040CN) was used, and the toner cartridge was filled in the toner cartridge of the developing device, and then the printing paper was set. After standing for 24 hours in a normal temperature and normal humidity (N / N) environment (temperature: 23 ° C., humidity: 50%), continuous printing was performed up to 10,000 sheets at a 5% print density in the same environment. .
Black solid printing (printing density 100%) was performed every 500 sheets, and the printing density of the black solid image was measured using a reflective image densitometer (trade name: RD918, manufactured by Macbeth). After that, white solid printing (printing density 0%) is performed, the printer is stopped in the middle of white solid printing, and the toner in the non-image area on the developed photosensitive member is adhesive tape (manufactured by Sumitomo 3M Ltd., product) Name: Scotch mending tape 810-3-18), and then peeled off and affixed to printing paper. Next, the whiteness (B) of the printing paper on which the adhesive tape is affixed is measured with a whiteness meter (trade name: ND-1 manufactured by Nippon Denshoku Co., Ltd.). The whiteness (A) was measured and the difference in whiteness (B−A) was defined as the fog value (%). Smaller values indicate better fog and better.
The number of continuously printed sheets that can maintain an image quality with a print density of 1.30 or more and a fog value of 3% or less was examined.
In Table 1, “10000 <” indicates that the image quality with the print density of 1.30 or more and the fog value of 3% or less could be maintained even at the time of 10,000 sheets.

  The measurement and evaluation results of the electrostatic charge image developing toners of Examples 1 to 5 and Comparative Examples 1 to 4 are shown in Table 2 together with the toner compositions.

6). Summary of Toner Evaluation First, the toner of Comparative Example 1 will be examined. The toner of Comparative Example 1 has a toner charge amount of 37 μC / g in a normal temperature and normal humidity (N / N) environment and a toner charge amount of 25 μC / g in a high temperature and high humidity (H / H) environment. A degree of electrification was shown. Further, the toner of Comparative Example 1 has a fog density of 0.2 in a normal temperature and normal humidity (N / N) environment and a fog generation number exceeding 10,000 in a normal temperature and normal humidity (N / N) environment. No problem was found in the printing durability at least in a normal temperature and normal humidity (N / N) environment.
However, the fluidity value of the toner of Comparative Example 1 was 80, indicating a result that was slightly inferior in fluidity. Further, the fog density of the toner of Comparative Example 1 in a high-temperature and high-humidity (H / H) environment is 8. Compared with the results of Examples 1 to 5 described later, fog of 3 times or more may occur. I understand.
From these results, it can be seen that the toner of Comparative Example 1 using silica fine particles A, which are conventional silica fine particles, is inferior in fluidity and printing durability in a high temperature and high humidity (H / H) environment.

Next, the toner of Comparative Example 2 will be examined. The toner of Comparative Example 2 had a fluidity value of 94, and there was no problem with fluidity. Further, the toner of Comparative Example 2 has a fog density of 0.8 in a normal temperature and normal humidity (N / N) environment and a fog generation number of 10,000 or more in a normal temperature and normal humidity (N / N) environment. No problem was found in the printing durability at least in a normal temperature and normal humidity (N / N) environment.
However, the toner of Comparative Example 2 has a toner charge amount of 18 μC / g in a normal temperature and normal humidity (N / N) environment and a toner charge amount of 14 μC / g in a high temperature and high humidity (H / H) environment. Among the toners of Examples 1 to 5 and Comparative Examples 1 to 4, the lowest charge amount was shown. Further, the fog density of the toner of Comparative Example 2 in a high-temperature and high-humidity (H / H) environment is 12. Compared with the results of Examples 1 to 5 which will be described later, fog of 5 times or more may occur. I understand.
From these results, the toner of Comparative Example 2 using silica fine particles B, which are conventional silica fine particles, has a low charge amount in a normal temperature and normal humidity (N / N) environment and a high temperature and high humidity (H / H) environment. It can also be seen that the printing durability is inferior in a high temperature and high humidity (H / H) environment.

Subsequently, the toner of Comparative Example 3 will be examined. The toner of Comparative Example 3 has a toner charge amount of 30 μC / g in a normal temperature and normal humidity (N / N) environment and a toner charge amount of 20 μC / g in a high temperature and high humidity (H / H) environment. A degree of electrification was shown.
However, the fluidity value of the toner of Comparative Example 3 was 69, and the poorest fluidity was exhibited among the toners of Examples 1 to 5 and Comparative Examples 1 to 4. Further, the fog density of the toner of Comparative Example 3 in a normal temperature and normal humidity (N / N) environment is 2.8, which is compared with the results of Examples 1 to 5 described later at normal temperature and normal humidity (N / N). It can be seen that fog of 4 times or more occurs in the environment. Further, the fog density of the toner of Comparative Example 3 in a high temperature and high humidity (H / H) environment is 25, and compared with the results of Examples 1 to 5 described later, the high temperature and high humidity (H / H) environment. It can be seen that fog is generated 10 times or more.
From these results, the toner of Comparative Example 3 using the core-shell type composite fine particles in which the volume ratio of the silica component is lower than the composite fine particles used in the present invention is fluid and has a normal temperature and normal humidity (N / N) environment. It can be seen that the printing durability is inferior under the low temperature and high temperature and high humidity (H / H) environment.

Subsequently, the toner of Comparative Example 4 will be examined. The fluidity value of the toner of Comparative Example 4 was 78, indicating that the fluidity was slightly inferior. The toner of Comparative Example 4 has a toner charge amount of 20 μC / g in a normal temperature and normal humidity (N / N) environment and a toner charge amount of 15 μC / g in a high temperature and high humidity (H / H) environment. As compared with the toners of Examples 1 to 5, the charge amount was low. Further, the fog density of the toner of Comparative Example 4 in a normal temperature and normal humidity (N / N) environment is 3.0, which is lower than the results of Examples 1 to 5 described below at normal temperature and normal humidity (N / N). It can be seen that fog of 4 times or more occurs in the environment. Further, the fog density of the toner of Comparative Example 4 in a high temperature and high humidity (H / H) environment is 22, and compared with the results of Examples 1 to 5 described later, the high temperature and high humidity (H / H) environment. It can be seen that fogging of 9 times or more occurs.
From these results, the toner of Comparative Example 4 using the core-shell type composite fine particles in which the volume ratio of the silica component is extremely lower than the composite fine particles used in the present invention is in a normal temperature and normal humidity (N / N) environment and at a high temperature. It can be seen that the charge amount under a high humidity (H / H) environment is low, the fluidity, and the printing durability under a normal temperature and normal humidity (N / N) environment and a high temperature and high humidity (H / H) environment are inferior.

  In contrast to the above Comparative Examples 1 to 4, the toners of Examples 1 to 5 have a fluidity of 86 or more and a toner charge amount of 25 μC / g or more in a normal temperature and normal humidity (N / N) environment. The toner charge amount in a high temperature and high humidity (H / H) environment is 21 μC / g or more, and the fog density in a normal temperature and normal humidity (N / N) environment is 0.8 or less. In addition, the fog density in a high-temperature and high-humidity (H / H) environment was 2.5 or less, and the number of fog occurrences in a normal temperature and normal humidity (N / N) environment was 7,000 or more. . Therefore, the volume ratio of the silica component of the composite fine particle is 45 to 75 volume when the surface of the resin fine particle is a core-shell composite fine particle coated with silica and the total volume of the composite fine particle is 100% by volume. % Of the core-shell type composite fine particles as external additives, the toners of Examples 1 to 5 have excellent fluidity and chargeability, and the image quality due to fog or the like is improved even when a large number of sheets are continuously printed. It turns out that deterioration does not occur easily.

Claims (8)

A toner for developing an electrostatic charge image, comprising colored resin particles containing a binder resin and a colorant, and an external additive,
The external additive is a core-shell composite fine particle in which the surface of the resin fine particle is coated with a continuous layer of silica, and the silica component of the composite fine particle when the total volume of the composite fine particle is 100% by volume A toner for developing electrostatic images, wherein the volume ratio is 45 to 75% by volume.   2. The electrostatic image developing toner according to claim 1, wherein the core-shell type composite fine particles have an adsorbed water content of 0.5 to 1.5 mass%.   3. The electrostatic charge image developing toner according to claim 1, wherein the addition amount of the core-shell type composite fine particles is 0.1 to 20 parts by mass with respect to 100 parts by mass of the colored resin particles.   The static resin according to any one of claims 1 to 3, wherein the colored resin particles have a volume average particle size of 4 to 12 µm and an average circularity of 0.96 to 1.00. Toner for charge image development.   5. The electrostatic image developing toner according to claim 1, wherein both the colored resin particles and the core-shell type composite fine particles exhibit positive chargeability.   6. The electrostatic charge image developing toner according to claim 1, wherein the core-shell composite fine particles have a number average particle diameter of 30 to 300 nm.   7. The electrostatic image developing toner according to claim 1, wherein the core-shell type composite fine particles have a blow-off charge amount of +1000 to +4000 μC / g. 8.   The electrostatic charge image developing toner according to claim 1, wherein the resin fine particles of the core-shell type composite fine particles are a crosslinked resin.