JP6056470B2 - Toner for electrostatic image development - Google Patents

Description

  The present invention relates to a toner for developing an electrostatic charge image that can be used for developing an image forming apparatus using electrophotography such as a copying machine, a facsimile machine, and a printer.

  Conventionally, in a developer used for general electrophotography, desired fluidity and charging characteristics can be obtained by attaching an external additive to the surface of the colored resin particles. As the external additive, fine particles made of inorganic or organic substances are widely used. As such an external additive, metal oxide particles and resin particles, and those obtained by surface treatment of these have been widely used. Among these, particles of metal oxides such as silica, titania, and alumina, and those obtained by hydrophobizing them are particularly used, and a combination of these is generally used.

  For example, in Patent Document 1, in a negatively chargeable toner in which a resin particle surface containing a colorant is coated with an external additive, the external additive has two types of silica particles having different average particle diameters, an oxide of a specific metal, or Disclosed is a negatively chargeable toner comprising silica particles surface-modified with hydroxide and hydrophobized aluminum oxide-silicon dioxide composite oxide particles obtained by a hydrolysis method. It is also disclosed that it can prevent property, filming prevention and fogging. Patent Document 2 discloses toner mother particles having an average volume particle diameter of 2 to 6 μm, at least two types of silica having different average particle diameters, specific electron conductive oxide semiconductor fine particles, and specific ion conductive oxide semiconductors. A toner containing fine particles is disclosed, and it is also disclosed that even a small particle diameter toner is excellent in charge uniformity and transfer efficiency.

  Patent Document 3 discloses that toner base particles obtained by phase inversion emulsification include hydrophobic silica fine particles having a specific particle size and hydrophobic titanium oxide fine particles having a specific particle size, as well as hydrophobic α-type alumina fine particles having a larger particle size. And / or a negatively charged toner in which hydrophobic silica fine particles are externally added, and a negatively charged toner in which the external additive particles are hydrophobized with a silane coupling agent are disclosed, and unevenness after high-temperature storage is disclosed. It is also disclosed that the difference in charge amount before and after durability is small and the uniformity of image quality is excellent. In Patent Document 4, in an electrophotographic toner in which inorganic fine particles are contained in colored particles, the inorganic fine particles include two or more types having an average particle diameter of 20 nm or less, and one or more types having a particle size of 30 nm or more. In addition, an electrophotographic toner is disclosed, and it is also disclosed that toner transferability, fine line reproducibility, charging environment stability, storage stability and the like are improved.

  However, the toners described in these patent documents cannot cope with the balance between the lowering of the fixing temperature and storage stability accompanying high-speed printing in recent years, and it is insufficient to keep the charge amount stable in different environments. there were.

JP 2005-37469 (Patent No. 4292386) JP 2010-249989 JP2011-59693A JP 2003-177567 A (Patent No. 39099839)

An object of the present invention is to provide a toner having an excellent balance between the fixing temperature and storage stability, excellent printing durability in a normal temperature and normal humidity (N / N) environment, and less likely to cause initial blurring or post-duration blurring. .
In addition, it exhibits stable charging performance in a wide range of temperature and humidity environments from low temperature and low humidity (L / L) to high temperature and high humidity (H / H), and charge-up is suppressed even in low temperature and low humidity (L / L) environments. The object is to provide a toner with less fog.

  As a result of intensive studies on the external additive constituting the electrostatic image developing toner together with the colored resin particles, the present inventor has combined three types of silica fine particles having a specific particle size and alumina fine particles having a specific particle size, It has been found that the above problems can be solved.

  That is, according to the present invention, in the electrostatic charge developing toner containing a binder resin and a colorant, and an external additive, the number average primary particle size is 36 to 100 nm as the external additive. A silica fine particle A, a silica fine particle B having a number average primary particle size of 15 to 35 nm, a silica fine particle C having a number average primary particle size of 6 to 14 nm, and an alumina fine particle having a number average primary particle size of 5 to 100 nm. A toner for developing an electrostatic charge image is provided.

  In the present invention, the total content of external additives is preferably 1.7 to 3.6 parts by mass with respect to 100 parts by mass of the colored resin particles.

  In the present invention, the total content of silica fine particles A to C in the external additive is preferably 1.6 to 3.0 parts by mass with respect to 100 parts by mass of the colored resin particles.

  In the present invention, with respect to 100 parts by mass of the colored resin particles, as external additives, the silica fine particles A are 0.5 to 2.9 parts by mass, the silica fine particles B are 0.1 to 2.0 parts by mass, It is preferable to contain 0.05 to 0.5 parts by mass of the silica fine particles C and 0.05 to 2 parts by mass of the alumina fine particles.

  According to the toner for developing an electrostatic charge image of the present invention as described above, low temperature fixability and storage can be achieved by containing three kinds of silica fine particles and one kind of alumina fine particles having a specific number average primary particle size as external additives. Excellent balance of properties, excellent printing durability under normal temperature and normal humidity (N / N) environment, extremely low initial and post-endurance blurring, and small difference in charge due to environment, low temperature and low humidity ( L / L) A toner with less charge-up and less fog is provided even in an environment.

  The toner for developing an electrostatic charge image of the present invention has a number average primary particle size of 36 as an external additive in the toner for electrostatic charge development containing a colored resin particle containing a binder resin and a colorant and an external additive. Silica fine particles A having a particle size of ˜100 nm, silica fine particles B having a number average primary particle size of 15 to 35 nm, silica fine particles C having a number average primary particle size of 6 to 14 nm, and number average primary particle size of 5 to 100 nm It contains alumina fine particles.

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 contains colored resin particles containing a binder resin and a colorant, and an external additive.
Hereinafter, the manufacturing method of the colored resin particles used in the present invention, the colored resin particles obtained by the manufacturing method, the manufacturing method of the toner of the present invention using the colored resin particles, 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, other additions such as a polymerizable monomer, a colorant, and a charge control agent added as necessary The product is mixed to prepare a polymerizable monomer composition. For mixing at the time of preparing the polymerizable monomer composition, for example, a media type disperser is used.

  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; and 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 esters or methacrylic esters are preferably used as monovinyl monomers.

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; Ester compounds in which two or more carboxylic acids having a carbon-carbon double bond are ester-bonded; other divinyl compounds such as N, N-divinylaniline and divinyl ether; compounds having three or more vinyl groups; Can be mentioned. 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, 186, and 213.

  Examples of the magenta colorant include compounds such as monoazo pigments, azo pigments such as disazo pigments, and condensed polycyclic pigments. 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, 238, 251, 254, 255, 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.

  From the viewpoint of improving the releasability of the toner from the fixing roll during fixing, it is preferable to add a release agent to the polymerizable monomer composition. Any releasing agent can be used without particular limitation as long as it is generally used as a releasing agent for toner.

The release agent preferably contains at least one of ester wax and hydrocarbon wax. By using these waxes as a release agent, the balance between low-temperature fixability and storage stability can be made suitable.
The ester wax suitably used as a release agent in the present invention is more preferably a polyfunctional ester wax, such as pentaerythritol ester such as pentaerythritol tetrapalinate, pentaerythritol tetrabehenate, pentaerythritol tetrastearate, etc. Compound: hexaglycerin tetrabehenate tetrapalinate, hexaglycerin octabehenate, pentaglycerin heptabehenate, tetraglycerin hexabehenate, triglycerin pentabehenate, diglycerin tetrabehenate, glycerin tribe Glycerin ester compounds such as henate; Dipentaerythritol ester compounds such as dipentaerythritol hexamyristate and dipentaerythritol hexapalmitate; It is.

Examples of the hydrocarbon wax suitably used as a release agent in the present invention include polyethylene wax, polypropylene wax, Fischer-Tropsch wax, petroleum-based wax, etc. Among them, Fischer-Tropsch wax and petroleum-based wax are preferable, and petroleum-based wax. Is more preferable.
The number average molecular weight of the hydrocarbon wax is preferably 300 to 800, more preferably 400 to 600. Moreover, the penetration of the hydrocarbon wax measured by JIS K2235 5.4 is preferably 1 to 10, and more preferably 2 to 7.

In addition to the mold release agent, for example, natural wax such as jojoba; mineral wax such as ozokerite;
The mold release agent may be used in combination with one or more waxes as described above.
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.

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. The toner of the present invention is preferably a positively chargeable toner.
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.

(A-2) Suspension step for obtaining a suspension (droplet formation step)
In the present invention, a polymerizable monomer composition containing at least a polymerizable monomer and a colorant is dispersed in an aqueous medium containing a dispersion stabilizer, and after adding a polymerization initiator, a polymerizable monomer Form body composition droplets. 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′-azobisisobutyronitrile Azo compounds such as: di-t-butyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxydiethyl acetate, t-hexylperoxy-2-ethylbutanoate Diisopropyl peroxydicarbonate, di-t-butylperoxyisophthalate, and t-butylperoxyiso Organic peroxides such as Chireto like. 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 preferable because non-aromatic peroxyesters, that is, peroxyesters having no aromatic ring, are preferable because initiator efficiency is good and the amount of remaining polymerizable monomers can be reduced. More preferred.

  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 toner can reproduce the image clearly and has excellent 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 added as necessary are mixed in a mixer, such as a ball mill, a V-type mixer, a Henschel mixer (trade name), a high-speed dissolver, Mix using an 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, as other additives such as a binder resin and a colorant used in the pulverization method, and a charge control agent added as necessary, 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 toner is lowered, the transferability may be deteriorated, and 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 circumference of 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.

3. Toner Production Method In the present invention, the colored resin particles are mixed and stirred together with an external additive and subjected to an external addition treatment, whereby the external additive is adhered to the surface of the colored resin particles to develop a one-component toner (development). Agent). The one-component toner may be further mixed and stirred together with carrier particles to form a two-component developer.

In the present invention, silica fine particles A having a number average primary particle size of 36 to 100 nm are contained as an external additive. When the number average primary particle size of the silica fine particles A is less than 36 nm, the spacer effect is lowered and print performance such as fogging may be adversely affected. On the other hand, when the number average primary particle size of the silica fine particles A exceeds 100 nm, the inorganic fine particles A are easily released from the surface of the toner particles, the function as an external additive is lowered, and the printing performance is adversely affected. May affect.
The number average primary particle size of the silica fine particles A is more preferably 40 to 80 nm, and further preferably 45 to 70 nm. Silica fine particles A are preferably hydrophobized. Examples of the hydrophobizing agent include hydrophobizing agents such as silane coupling agents, silicone oils, fatty acids and fatty acid metal salts, and silane coupling agents and silicone oils are more preferable from the viewpoint of obtaining high image quality. .

Examples of silane coupling agents include disilazane such as hexamethyldisilazane; cyclic silazane; trimethylsilane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, benzyldimethylchlorosilane, methyltrimethoxysilane. , Methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-butyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, Alkylsilane compounds such as vinyltriacetoxysilane, and γ-aminopropyltriethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, aminosilane, And aminosilane compounds such as N- (2-aminoethyl) 3-aminopropyltrimethoxysilane and N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane;
Examples of the silicone oil include dimethylpolysiloxane, methylhydrogenpolysiloxane, methylphenylpolysiloxane, and amino-modified silicone oil.
Of the above, only one type of hydrophobic treatment agent may be used, or two or more types may be used.
When obtaining a positively chargeable developer, it is more preferable to use a silicon compound containing an amino group, such as an aminosilane compound or an amino-modified silicone oil, because a developer having good positive chargeability is easily obtained.

The content of the silica fine particles A is preferably 0.5 to 2.9 parts by mass, more preferably 0.7 to 2.5 parts by mass with respect to 100 parts by mass of the colored resin particles. More preferably, it is 0.0-2.0 mass parts.
When the content of the silica fine particles A is less than 0.5 parts by mass, the function as the external additive cannot be sufficiently exhibited, and the printing performance may be adversely affected. On the other hand, when the content of the silica fine particles A exceeds 2.9 parts by mass, the silica fine particles A are easily released from the surface of the toner particles, the function as an external additive is lowered, and the printing performance is adversely affected. May affect.
Although depending on the type and content of other external additives and other external additive conditions, the higher the content of silica fine particles A, the more the printing durability and storage stability are improved. The difference in performance tends to narrow.

In the present invention, silica fine particles B having a number average primary particle size of 15 to 35 nm are contained as an external additive. When the number average primary particle diameter of the silica fine particles B is less than 15 nm, the silica fine particles B are easily embedded from the surface to the inside of the colored resin particles, and sufficient fluidity can be imparted to the toner particles. The printing performance may be adversely affected. On the other hand, when the number average primary particle size of the silica fine particles B exceeds 35 nm, the proportion (coverage) of the silica fine particles B with respect to the surface of the toner particles is reduced, so that the toner particles have sufficient fluidity. May not be granted.
The number average primary particle size of the silica fine particles B is more preferably 17 to 30 nm, and further preferably 20 to 25 nm. Silica fine particles B are preferably hydrophobized. As the hydrophobizing agent, the same one used for the silica fine particles A can be used.

The content of the silica fine particles B is preferably 0.1 to 2.0 parts by mass, more preferably 0.2 to 1.5 parts by mass with respect to 100 parts by mass of the colored resin particles. More preferably, it is 3 to 1.0 parts by mass.
When the content of the silica fine particles B is less than 0.1 parts by mass, the function as an external additive cannot be sufficiently exerted, and the fluidity is lowered or the storage stability and durability are lowered. There is. On the other hand, when the content of the silica fine particles B exceeds 2.0 parts by mass, the silica fine particles B are likely to be liberated from the surface of the toner particles, the chargeability in a high temperature and high humidity environment is reduced, and fogging occurs. There is a case.
Although depending on the type and content of other external additives and other external addition conditions, the higher the content of silica fine particles B, the less the wear after durability and the lower the charge amount under different environments. The difference tends to narrow, and the lower the content of the silica fine particles B, the better the low-temperature fixability.

In the present invention, silica fine particles C having a number average primary particle size of 6 to 14 nm are contained as an external additive. When the number average primary particle size of the silica fine particles C is less than 6 nm, the silica fine particles C are easily embedded from the surface to the inside of the colored resin particles, and sufficient fluidity can be imparted to the toner particles. The printing performance may be adversely affected. On the other hand, when the number average primary particle size of the silica fine particles C exceeds 14 nm, the ratio (coverage) of the silica fine particles C to the surface of the toner particles is reduced, so that the toner particles have sufficient fluidity. May not be granted.
The number average primary particle size of the silica fine particles C is more preferably 6.5 to 12 nm, and further preferably 7 to 10 nm. Silica fine particles C are preferably hydrophobized. As the hydrophobizing agent, the same one used for the silica fine particles A can be used.

The content of the silica fine particles C is preferably 0.05 to 0.5 parts by mass, more preferably 0.1 to 0.4 parts by mass with respect to 100 parts by mass of the colored resin particles. More preferably, it is 2 to 0.3 parts by mass.
When the content of the silica fine particles C is less than 0.05 parts by mass, the function as an external additive cannot be sufficiently exerted, and the fluidity is lowered or the storage stability and durability are lowered. There is. On the other hand, when the content of the silica fine particles C exceeds 0.5 parts by mass, the silica fine particles C are easily released from the surface of the toner particles, and the chargeability in a high-temperature and high-humidity environment is lowered and fogging occurs. There is a case.
Although depending on the type and content of other external additives and other external addition conditions, the higher the content of the silica fine particles C, the more the initial blurring tends to be suppressed. The lower the content of, the better the low-temperature fixability.

Various commercially available products can be used as the silica fine particles A. For example, VPNA50H manufactured by Nippon Aerosil Co., Ltd. (: product name, number average primary particle size: 40 nm); H05TA manufactured by Clariant Co., Ltd. (: product name, number average) Primary particle size: 50 nm);
Various commercially available products can be used as the silica fine particles B. For example, NA50Y (: trade name, number average primary particle size: 35 nm) manufactured by Nippon Aerosil Co., Ltd .; MSP-012 (: trade name, manufactured by Teika Co., Ltd.) Number average primary particle size: 16 nm); TG-7120 manufactured by Cabot Corporation (: trade name, number average primary particle size: 20 nm) and the like.
Various commercially available products can be used as the silica fine particles C. For example, HDK2150 manufactured by Clariant (trade name, number average primary particle size: 12 nm); R504 manufactured by Nippon Aerosil Co., Ltd. (: trade name, number average) Primary particle size: 12 nm), RA200HS (: trade name, number average primary particle size: 12 nm); MSP-013 manufactured by Teika (: trade name, number average primary particle size: 12 nm); TG-820F manufactured by Cabot Corporation (: Trade name, number average primary particle size: 7 nm) and the like.

In the present invention, alumina fine particles having a number average primary particle size of 5 to 100 nm are contained as an external additive. When the number average primary particle size of the alumina fine particles is less than 5 nm, the charge amount under a high-temperature and high-humidity (H / H) environment is remarkably reduced, and print fogging may occur. On the other hand, when the number average primary particle size of the alumina fine particles exceeds 100 nm, the charge amount is significantly increased in a low temperature and low humidity (L / L) environment, and print fogging may occur.
The number average primary particle size of the alumina fine particles is more preferably 10 to 75 nm, and further preferably 15 to 50 nm. In addition, the alumina fine particles may be hydrophobized.

The content of the alumina fine particles is preferably 0.05 to 2 parts by mass, more preferably 0.1 to 1.5 parts by mass with respect to 100 parts by mass of the colored resin particles, and 0.2 to More preferably, it is 1.0 part by mass.
When the content of the alumina fine particles is less than 0.05 parts by mass, the charge amount increases remarkably in a low temperature and low humidity (L / L) environment, and print fogging may occur. On the other hand, when the content of the alumina fine particles exceeds 2 parts by mass, the charge amount under a high-temperature and high-humidity (H / H) environment is significantly reduced, and print fogging may occur.
Although the detailed mechanism is not clear, it is presumed that the effect of uniformizing the charge amount of the toner is exhibited when the content of the alumina fine particles with respect to the colored resin particles is within the above range.
Further, although depending on the type and content of other external additives and other external addition conditions, as shown in the examples described later, the higher the content of alumina fine particles, the lower the temperature and humidity environment (L / L) tends to reduce the charge amount and suppress charge-up. Further, the lower the content of alumina fine particles, the better the low-temperature fixability.

  In addition, the number average primary particle diameter of the external additive particles used in the present invention can be measured, for example, as follows. First, the particle diameter of each particle of the external additive is measured with a transmission electron microscope (TEM) or the like. Thus, the particle diameter of 200 or more external additive particles is measured, and the average value is defined as the number average primary particle diameter of the particles.

  As the alumina fine particles, various commercially available products can be used. For example, AKP-G015 manufactured by Sumitomo Chemical Co., Ltd. (: trade name, number average primary particle size: 18 nm); AEROSIL Alu C produced by Aerosil Co. (: trade name) , Number average primary particle size: 65 nm);

  The stirrer that performs the external addition treatment is not particularly limited as long as the stirrer can attach the external additive to the surface of the colored resin particles. For example, Henschel mixer (trade name, manufactured by Mitsui Mining Co., Ltd.), FM mixer (: Trade name, manufactured by Nippon Coke Industries Co., Ltd.), super mixer (: product name, manufactured by Kawada Seisakusho Co., Ltd.), Q mixer (: product name, manufactured by Nihon Coke Industries Co., Ltd.), mechano-fusion system (: trade name, Hosokawa Micron Corporation) And a mechano mill (trade name, manufactured by Okada Seiko Co., Ltd.) and the like, and a stirrer capable of mixing and stirring can be used for external addition treatment.

4). Toner of the present invention The toner of the present invention has an excellent balance between low-temperature fixability and storage stability, excellent printing durability under a normal temperature and normal humidity (N / N) environment, and is very unlikely to cause initial or post-duration. Further, since the difference in charge amount depending on the environment is small, the toner is less fogged and suppressed in charge-up even in a low temperature and low humidity (L / L) environment.

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 toner for developing electrostatic image [Example 1]
75 parts of styrene and 25 parts of n-butyl acrylate as a polymerizable monomer, 5 parts of carbon black (trade name “# 25B”, manufactured by Mitsubishi Chemical Corporation) as a black colorant, an in-line type emulsifying disperser (manufactured by Ebara Corporation) , Trade name “Ebara Milder”) to obtain a polymerizable monomer mixture.
In the above polymerizable monomer mixture, 1 part of a positively chargeable charge control resin as a charge control agent, 5 parts of a polyfunctional ester wax (manufactured by NOF Corporation, trade name “WEP7”) as a release agent, and polymethacryl as a macromonomer 0.3 part of an acid ester macromonomer (trade name “AA6” manufactured by Toagosei Co., Ltd.), 0.6 part of divinylbenzene as a crosslinkable polymerizable monomer, and t-dodecyl mercaptan as a molecular weight regulator. Six parts were added, mixed and dissolved to prepare a polymerizable monomer composition.

  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 metal hydroxide) 6.2 in 50 parts of ion-exchanged water. The aqueous solution in which the part was dissolved was gradually added with stirring to prepare a magnesium hydroxide colloid (slightly water-soluble metal hydroxide colloid) dispersion.

  The polymerizable monomer composition was charged into the magnesium hydroxide colloid dispersion at room temperature and stirred. Then, 4.4 parts of t-butylperoxydiethyl acetate was added as a polymerization initiator, and then rotated at 15,000 rpm using an in-line type emulsifying disperser (trade name “Ebara Milder” manufactured by Ebara Seisakusho Co., Ltd.). Dispersion was carried out by high-speed shearing stirring for several minutes for several minutes to form droplets of the polymerizable monomer composition.

  A suspension (polymerizable monomer composition dispersion) in which droplets of the polymerizable monomer composition are dispersed is placed in a reactor equipped with a stirring blade, heated to 90 ° C., and polymerized. The reaction was started. 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) Add 0.3 part of 2-methyl-N- (2-hydroxyethyl) -propionamide) (manufactured by Wako Pure Chemical Industries, trade name “VA-086”, water-soluble) and continue the reaction at 90 ° C. for 4 hours. Then, the reaction was stopped by cooling with water to obtain an aqueous dispersion of colored resin particles having a core-shell structure.

  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, and dehydration) was repeated several times. Next, filtration separation is performed, and the obtained solid content is put in a container of a dryer, and dried at 45 ° C. for 48 hours. The volume average particle diameter (Dv) is 7.8 μm, and the number average particle diameter (Dn) is Colored resin particles having a size of 6.9 μm, a particle size distribution (Dv / Dn) of 1.13, and an average circularity of 0.987 were obtained.

  To 100 parts of the colored resin particles obtained above, 1.5 parts of silica fine particles A (number average primary particle size: 50 nm, manufactured by Clariant, trade name “H05TA”) as an external additive, silica fine particles B (number average) Primary particle diameter: 20 nm, manufactured by Cabot Corporation, trade name “TG-7120”) 0.3 part, silica fine particle C (number average primary particle diameter: 7 nm, manufactured by Cabot Corporation, trade name “TG-820F”) 0.2 0.5 part of alumina a (number average primary particle size: 18 nm, manufactured by Sumitomo Chemical Co., Ltd., trade name “AKP-G015”) is added as a part and alumina fine particles, and a 10-liter lab-scale lab scale having a cooling jacket is added. The toner of Example 1 was subjected to external addition treatment by mixing and stirring using a high speed stirring device (trade name “FM mixer” manufactured by Nippon Coke Co., Ltd.) at a peripheral speed of the stirring blade of 40 m / second and an external treatment time of 300 seconds. Obtained. The test results are shown in Table 1. In Example 1, the total addition amount of silica fine particles A to C in the external additive is 2.0 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 2.5. Part.

[Example 2]
In Example 1, the toner for developing an electrostatic charge image of Example 2 was prepared in the same manner as in Example 1 except that the addition amount of the silica fine particles A was changed from 1.5 parts to 2.5 parts. It used for the test. In Example 2, the total amount of silica fine particles A to C in the external additive is 3.0 parts with respect to 100 parts of the colored resin particles, and the total additive amount of the external additive is 3.5. Part.

[Example 3]
In Example 1, except that the addition amount of silica fine particles A was changed from 1.5 parts to 0.5 parts and the addition amount of silica fine particles B was changed from 0.3 parts to 0.8 parts, In the same manner as in Example 1, the toner for developing an electrostatic charge image of Example 3 was prepared and used for the test. In Example 3, the total amount of silica fine particles A to C in the external additive is 1.5 parts with respect to 100 parts of the colored resin particles, and the total additive amount of the external additive is 2.0. Part.

[Example 4]
In Example 1, the toner for developing an electrostatic charge image of Example 4 was prepared in the same manner as in Example 1 except that the addition amount of the silica fine particles B was changed from 0.3 part to 0.1 part. It used for the test. In Example 4, the total addition amount of silica fine particles A to C in the external additive is 1.8 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 2.3. Part.

[Example 5]
In Example 1, the toner for developing an electrostatic charge image of Example 5 was prepared in the same manner as in Example 1 except that the addition amount of the silica fine particles C was changed from 0.2 part to 0.4 part. It used for the test. In Example 5, the total addition amount of silica fine particles A to C in the external additive is 2.2 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 2.7. Part.

[Example 6]
In Example 1, the toner for developing an electrostatic charge image of Example 6 was prepared in the same manner as in Example 1 except that the addition amount of the silica fine particles C was changed from 0.2 part to 0.1 part. It used for the test. In Example 6, the total addition amount of silica fine particles A to C in the external additive is 1.9 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 2.4. Part.

[Example 7]
In Example 1, the toner for developing an electrostatic charge image of Example 7 was prepared and tested in the same manner as in Example 1 except that the addition amount of alumina a was changed from 0.5 part to 1.5 parts. It was used for. In Example 7, the total addition amount of silica fine particles A to C in the external additive is 2.0 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 3.5 parts. Part.

[Example 8]
In Example 1, the toner for developing an electrostatic charge image of Example 8 was prepared and tested in the same manner as in Example 1 except that the addition amount of alumina a was changed from 0.5 part to 0.1 part. It was used for. In Example 8, the total addition amount of silica fine particles A to C in the external additive is 2.0 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 2.1. Part.

[Example 9]
In Example 1, instead of 0.5 part of alumina a (number average primary particle size: 18 nm, manufactured by Sumitomo Chemical Co., Ltd., trade name “AKP-G015”) as alumina fine particles, alumina b (number average primary particle size: 65 nm, manufactured by Aerosil Co., Ltd. (trade name “AEROSIL Alu C”) was added in the same manner as in Example 1 except that 0.5 part was added, and the electrostatic image developing toner of Example 9 was prepared and used for the test. did. In Example 9, the total amount of silica fine particles A to C in the external additive is 2.0 parts with respect to 100 parts of the colored resin particles, and the total additive amount of the external additive is 2.5 parts. Part.

[Example 10]
In Example 1, except that the addition amount of silica fine particles B was changed from 0.3 part to 0.7 part and the addition amount of alumina a was changed from 0.5 part to 0.1 part. In the same manner as in Example 1, the toner for developing an electrostatic charge image of Example 10 was prepared and used for the test. In Example 10, the total addition amount of silica fine particles A to C in the external additive is 2.4 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 2.5. Part.

[Example 11]
In Example 1, the toner for developing an electrostatic charge image of Example 11 was prepared in the same manner as in Example 1 except that the addition amount of the silica fine particles B was changed from 0.3 part to 1.5 parts. It used for the test. In Example 11, with respect to 100 parts of the colored resin particles, the total amount of silica fine particles A to C in the external additive is 3.2 parts, and the total additive amount of the external additive is 3.7. Part.

[Example 12]
In Example 1, except that the addition amount of silica fine particles A was changed from 1.5 parts to 1.0 part and the addition amount of silica fine particles C was changed from 0.2 parts to 0.7 parts, In the same manner as in Example 1, the toner for developing an electrostatic charge image of Example 12 was prepared and used for the test. In Example 12, the total addition amount of silica fine particles A to C in the external additive is 2.0 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 2.5. Part.

[Example 13]
In Example 1, the addition amount of silica fine particles B was changed from 0.3 parts to 0.8 parts, the addition amount of silica fine particles C was changed from 0.2 parts to 0.7 parts, and alumina was added. A toner for developing an electrostatic charge image of Example 13 was produced in the same manner as in Example 1 except that the addition amount of a was changed from 0.5 part to 1.2 parts, and was subjected to the test. In Example 13, the total addition amount of silica fine particles A to C in the external additive is 3.0 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 4.2. Part.

[Example 14]
In Example 1, except that the addition amount of silica fine particles A was changed from 1.5 parts to 1.0 part and the addition amount of alumina a was changed from 0.5 parts to 1.2 parts. In the same manner as in Example 1, the electrostatic image developing toner of Example 14 was prepared and used for the test. In Example 14, the total addition amount of silica fine particles A to C in the external additive is 1.5 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 2.7. Part.

[Example 15]
In Example 1, the addition amount of silica fine particles A was changed from 1.5 parts to 0.5 parts, the addition amount of silica fine particles B was changed from 0.3 parts to 0.8 parts, and alumina was added. A toner for developing an electrostatic charge image of Example 15 was produced in the same manner as in Example 1 except that the addition amount of a was changed from 0.5 part to 1.5 parts, and was subjected to the test. In Example 15, the total addition amount of silica fine particles A to C in the external additive is 1.5 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 3.0 parts. Part.

[Comparative Example 1]
A toner for developing an electrostatic charge image of Comparative Example 1 was produced in the same manner as in Example 1 except that no alumina fine particles were added in Example 1, and the toner was used for the test. In Comparative Example 1, the total addition amount of the silica fine particles A to C and the total addition amount of the external additive are both 2.0 parts with respect to 100 parts of the colored resin particles.

[Comparative Example 2]
In Example 1, the addition amount of silica fine particles B was changed from 0.3 part to 0.8 part, and alumina fine particles were not added. A toner for developing an electrostatic image was prepared and subjected to a test. In Comparative Example 2, the total addition amount of the silica fine particles A to C and the total addition amount of the external additive in the external additive is 2.5 parts with respect to 100 parts of the colored resin particles.

[Comparative Example 3]
Comparative Example 3 was carried out in the same manner as in Example 1 except that the addition amount of the silica fine particles A was changed from 1.5 parts to 2.0 parts in Example 1 and the silica fine particles B were not added. A toner for developing an electrostatic image was prepared and subjected to a test. In Comparative Example 3, the total addition amount of silica fine particles A to C in the external additive is 2.2 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 2.7. Part.

[Comparative Example 4]
In Example 1, the toner for developing an electrostatic charge image of Comparative Example 4 was produced in the same manner as in Example 1 except that the silica fine particle B was not added, and was subjected to the test. In Comparative Example 4, the total addition amount of silica fine particles A to C in the external additive is 1.7 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 2.2. Part.

[Comparative Example 5]
In Example 1, except that the silica fine particles B were not added and the addition amount of the silica fine particles C was changed from 0.2 part to 0.5 part, A toner for developing an electrostatic image was prepared and subjected to a test. In Comparative Example 5, the total amount of silica fine particles A to C in the external additive is 2.0 parts with respect to 100 parts of the colored resin particles, and the total additive amount of the external additive is 2.5. Part.

[Comparative Example 6]
In Example 1, except that the silica fine particles A were not added and the addition amount of alumina a was changed from 0.5 part to 1.5 parts, the static electricity of Comparative Example 6 was changed in the same manner as in Example 1. A toner for developing a charge image was prepared and subjected to a test. In Comparative Example 6, the total addition amount of silica fine particles A to C in the external additive is 0.5 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 2.0. Part.

[Comparative Example 7]
In Example 1, except that the silica fine particles A were not added and the addition amount of the silica fine particles B was changed from 0.3 part to 1.8 parts, the same as in Example 1 was repeated. A toner for developing an electrostatic image was prepared and subjected to a test. In Comparative Example 7, the total addition amount of silica fine particles A to C in the external additive is 2.0 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 2.5. Part.

[Comparative Example 8]
In Example 1, the toner for developing an electrostatic charge image of Comparative Example 8 was produced in the same manner as in Example 1 except that the silica fine particles C were not added, and were subjected to the test. In Comparative Example 8, the total addition amount of silica fine particles A to C in the external additive is 1.8 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 2.3. Part.

[Comparative Example 9]
Comparative Example 9 was performed in the same manner as in Example 1 except that the addition amount of the silica fine particles B was changed from 0.3 part to 1.0 part in Example 1 and the silica fine particles C were not added. A toner for developing an electrostatic image was prepared and subjected to a test. In Comparative Example 9, the total addition amount of silica fine particles A to C in the external additive is 2.5 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 3.0. Part.

[Comparative Example 10]
In Example 1, the addition amount of silica fine particles A was changed from 1.5 parts to 1.0 part, the addition amount of silica fine particles B was changed from 0.3 parts to 0.8 parts, and alumina was added. As fine particles, alumina c (number average primary particle size: 200 nm, manufactured by Sumitomo Chemical Co., Ltd.) instead of 0.5 part of alumina a (number average primary particle size: 18 nm, manufactured by Sumitomo Chemical Co., Ltd., trade name “AKP-G015”) The toner for developing an electrostatic charge image of Comparative Example 10 was prepared in the same manner as in Example 1 except that 0.5 part of a trade name “AKP-50”) was added and subjected to the test. In Comparative Example 10, the total addition amount of silica fine particles A to C in the external additive is 2.0 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 2.5 parts. Part.

[Comparative Example 11]
In Example 1, instead of 0.5 part of alumina fine particles (alumina a), titanium oxide d (number average primary particle size: 15 nm, trade name “JMT-150ANO”) as other fine particles was used. A toner for developing an electrostatic charge image of Comparative Example 11 was produced in the same manner as in Example 1 except that 5 parts were added, and was subjected to the test. In Comparative Example 11, the total addition amount of silica fine particles A to C in the external additive is 2.0 parts with respect to 100 parts of the colored resin particles, and the total addition amount of the external additive is 2.5. Part.

  Tables 1 and 2 show the compositions of the external additives in the electrostatic image developing toners of Examples 1 to 15 and Comparative Examples 1 to 11.

2. Evaluation of electrostatic charge image developing toner With respect to the electrostatic charge image developing toners of Examples 1 to 15 and Comparative Examples 1 to 11, coloring resin particle characteristics, toner characteristics, and printing characteristics were examined. Details are as follows.

2-1. Colored resin particle characteristics and toner characteristics 2-1-1. Volume average particle size (Dv), number average particle size (Dn) and particle size distribution (Dv / Dn) of colored resin particles
About 0.1 g of a measurement sample (colored resin particles) was weighed and taken in a beaker, and 0.1 mL of an alkylbenzene sulfonic acid aqueous solution (trade name “Drywell”, manufactured by Fuji Film) was added as a dispersant. After adding 10-30 mL of Isoton II to the beaker and dispersing for 3 minutes with a 20 W (Watt) ultrasonic disperser, use a particle size analyzer (Beckman Coulter, trade name “Multisizer”). The volume average particle diameter (Dv) and the number average particle diameter (Dn) of the colored resin particles are measured under the conditions of aperture diameter: 100 μm, medium: Isoton II, number of measured particles: 100,000 particles, The diameter distribution (Dv / Dn) was calculated.

2-1-2. Average circularity of colored resin particles 10 mL of ion-exchanged water is put in a container in advance, 0.02 g of a surfactant (alkylbenzenesulfonic acid) is added as a dispersant, and 0.02 g of a measurement sample (colored resin particles) is further added. Then, the dispersion treatment was performed with an ultrasonic disperser at 60 W (Watt) for 3 minutes. 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 Co., Ltd.). The average circularity was determined from the measured value.
The circularity is shown in the following calculation formula 1, and the average circularity is an average of the circularity.
Formula 1: (Circularity) = (Perimeter of circle equal to projected area of particle) / (Perimeter of projected image of particle)

2-1-3. Toner storability 20 g of toner is filled in a polyethylene container with a capacity of 100 mL, sealed with a lid sealed so that water does not enter, and water in a constant temperature water bath (manufactured by Yamato Scientific Co., Ltd .: BK300) set at 55 ° C. The container was submerged and removed after 8 hours. From the container, the toner was transferred onto a 42 mesh sieve (aperture 355 μm) as much as possible without vibration, and set in a powder measuring machine (trade name “Powder Tester PT-X” manufactured by Hosokawa Micron). After setting the sieve amplitude to 1.0 mm and vibrating for 30 seconds, the mass of the toner remaining on the sieve was measured, and the storage stability was evaluated as the mass of the aggregated toner.

2-1-4. Toner charge amount, print density (LL environment, HH environment)
A commercially available non-magnetic one-component developing type printer (HL-4570CDW) was used for the measurement of the charge amount.
The toner cartridge of the developing device of the printer is filled with toner and left in a high-temperature and high-humidity (H / H) environment (temperature: 33 ° C., humidity: 80%) for 24 hours. One white solid print was performed. Next, using an electrometer (manufactured by Advantest, trade name “TR8652”), the toner on the developing roll in a high-temperature and high-humidity environment (temperature: 33 ° C., humidity: 80%) was collected, and the charge amount was measured. As shown in the following calculation formula 2, the toner charge amount was calculated by dividing the measured charge amount value by the mass of the collected toner.
Calculation formula 2: toner charge amount (μC / g) = measured charge amount (μC) / collected toner mass (g)
The image density (ID) of the obtained black solid print was measured with a reflection type densitometer (manufactured by Macbeth, trade name “RD918”).
Similarly, the toner charge amount and the image density in a low temperature and low humidity (L / L) environment (temperature: 10 ° C., humidity: 20%) were calculated. Further, the ratio of the toner charge amount in the low temperature and low humidity (L / L) environment to the toner charge amount in the high temperature and high humidity (H / H) environment, and the low temperature and low humidity (L / L) in the high temperature and high humidity (H / H) environment. L) The image density difference from the environment was also calculated.

2-2. Printing characteristics 2-2-1. Fixing temperature A fixing test was performed using a printer modified so that the temperature of the fixing roll of a commercially available non-magnetic one-component developing type printer (printing speed: 20 sheets / min) could be changed. In the fixing test, the fixing roll temperature of the modified printer was changed in increments of 5 ° C., and the toner fixing rate at each temperature was measured.
The fixing rate was calculated from the ratio of the image density before and after the tape peeling operation in the black solid area printed on the test paper with the modified printer. That is, when the image density before tape peeling is ID (front) and the image density after tape peeling is ID (back), the fixing ratio can be calculated from the following equation.
Fixing rate (%) = (ID (back) / ID (front)) × 100
Here, the tape peeling operation means that an adhesive tape (manufactured by Sumitomo 3M Co., Ltd., trade name “Scotch Mending Tape 810-3-18”) is applied to the measurement part (black solid area) of the test paper and pressed with a constant pressure. The adhesive tape is then peeled off in a direction along the paper at a constant speed. The image density was measured using a reflection densitometer (manufactured by Macbeth, trade name “RD918”).
In this fixing test, the minimum fixing roll temperature at which the fixing rate is 80% or more was defined as the minimum fixing temperature of the toner.

2-2-2. Fog (under low temperature and low humidity (L / L) environment)
A commercially available non-magnetic one-component developing type printer (HL-4570CDW) was used for the fog. After the developer was filled in the toner cartridge of the developing device, the printing paper was set and left in a low temperature and low humidity (L / L) environment at a temperature of 10 ° C. and a relative humidity of 20% for 24 hours.
After leaving, one sheet of black solid printing was performed, and then one sheet of white solid printing was performed, and the whiteness on the paper surface of the white solid printed matter was measured using a whiteness meter (manufactured by Nippon Denshoku).
The fog value was calculated by setting ((whiteness of printing paper before printing) − (whiteness of white solid printed matter)) = fogging value.

2-2-3. Printing durability For the printing durability test, a commercially available non-magnetic one-component developing type printer (HL-4570CDW) was used. After the toner cartridge of the developing device was filled with toner, 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 15,000 sheets at 5% printing density in the same environment. . Every 500 sheets, black solid printing (printing density 100%) is performed, and using a reflective image densitometer (manufactured by Macbeth, trade name “RD918”), the printing density at the center of the black solid image is measured at three points. The average value was defined as the print density.
Furthermore, 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 photoconductor after development is treated with an adhesive tape (manufactured by Sumitomo 3M Limited, product The name “Scotch Mending Tape 810-3-18”) was peeled off and affixed to the printing paper. Next, the whiteness (B) of the printing paper to which the adhesive tape was attached was measured with a whiteness meter (trade name “ND-1”, manufactured by Nippon Denshoku Co., Ltd.), and in the same manner, an unused adhesive. Only the tape was attached to the printing paper, the whiteness (A) was measured, and the whiteness difference (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 1.3 or more and a fog value of 3% or less was examined.
In Tables 3 and 4, “15000 <” means that even at 15,000 sheets, the image density was 1.3 or higher and the fog value was 3% or less. Indicates.

2-2-4. Initial Scratch and Scratch after Durability In addition to the evaluation of “2-2-3. Printing Durability”, the evaluation of initial scum and post-durability scum was also performed.
For the initial blur, in the solid black printed material after printing 500 sheets in the endurance printability test, the print density was measured at each of three points, the black solid image upper part and the black solid image lower part. The difference between the upper print density and the lower print density was calculated as the print density, and used as an index of blur.
Scratch after endurance is evaluated in the same manner as initial scoring when the above test is completed with 15,000 continuous prints or when the above test is interrupted with less than 15,000 continuous prints due to poor durability. Carried out.

Tables 3 and 4 show the measurement and evaluation results of the electrostatic charge image developing toners of Examples 1 to 16 and Comparative Examples 1 to 11.
In Table 4 below, “* 1” described in the evaluation of “fog LL environment”, “image density”, “number of printed sheets”, “initial scratch”, and “scratch after durability” in Comparative Example 6 is: It means that the evaluation was stopped due to printing failure. In Table 4 below, “* 2” described in the evaluation of “scratch after durability” in Comparative Example 8 means that the evaluation was not performed because solid printing was impossible.

3. Evaluation of Toner Hereinafter, the evaluation results of the electrostatic image developing toner will be examined with reference to Tables 1 to 4.
From Table 2, the toners of Comparative Example 1 and Comparative Example 2 are toners containing only silica fine particles A to C and no alumina fine particles. From Table 4, the toners of Comparative Example 1 and Comparative Example 2 each have a blocking amount of 0.2 g, the minimum fixing temperature is 155 ° C. or 160 ° C., and the number of continuous prints in the print durability test both exceeds 15,000. The ID difference in the initial blur evaluation is 0.03 or 0.04, and the ID difference in the post-endurance blur evaluation is 0.07 or 0.08. Therefore, the toners of Comparative Example 1 and Comparative Example 2 have no problems in at least storage stability, low-temperature fixability, printing durability, and initial and post-duration blur.
However, the toners of Comparative Example 1 and Comparative Example 2 have a charge amount ratio in a low-temperature, low-humidity (L / L) environment to a charge amount in a high-temperature, high-humidity (H / H) environment (hereinafter referred to as the charge amount ratio). Is very large at 2.32 or 2.10. Further, the fog value (hereinafter sometimes referred to as LL fog value) in a low temperature and low humidity (L / L) environment is as extremely high as 5.8 or 4.2. In particular, these values in Comparative Example 1 are the largest among the toners of Examples 1 to 16 and Comparative Examples 1 to 11. Further, the difference between the ID under the high temperature and high humidity (H / H) environment and the ID under the low temperature and low humidity (L / L) environment (hereinafter sometimes referred to as an ID difference depending on the environment) is 0.40 or 0. .42 and large.
Therefore, the toners of Comparative Example 1 and Comparative Example 2 that do not contain alumina fine particles having a number average primary particle size of 5 to 100 nm are in a high temperature and high humidity (H / H) environment and a low temperature and low humidity (L / L) environment. It can be seen that there is a large difference in performance, and fog is likely to occur due to charge-up in a low temperature and low humidity (L / L) environment.

From Table 2, the toner of Comparative Example 10 contains both silica fine particles A to C and alumina fine particles, but the number average primary particle size of the alumina fine particles is 200 nm. From Table 4, the toner of Comparative Example 10 has a charge amount ratio of 1.67, a minimum fixing temperature of 160 ° C., an LL fog value of 0.5, an environmental ID difference of 0.22, and an initial blur evaluation. The ID difference is 0.06. Therefore, the toner of Comparative Example 10 has no problems in at least charging stability, low-temperature fixability, charging property in a low-temperature and low-humidity (L / L) environment, environmental stability, and initial blur.
However, the toner of Comparative Example 10 has a large blocking amount of 2.3 g. Further, the toner of Comparative Example 10 has a small continuous print number of 10,000 in the print durability test. Further, the toner of Comparative Example 10 has a large ID difference of 0.23 in evaluation of blur after durability.
Therefore, it can be seen that the toner of Comparative Example 10 containing alumina fine particles having a number average primary particle size exceeding 100 nm is extremely inferior in storage stability, inferior in printing durability, and more likely to be damaged after durability.

From Table 2, the toner of Comparative Example 11 is a toner containing silica fine particles A to C and titanium oxide particles having a number average primary particle size of 15 nm and no alumina fine particles. From Table 4, the toner of Comparative Example 11 has a blocking amount of 0.2 g, a minimum fixing temperature of 160 ° C., a continuous printing number exceeding 15,000 in the printing durability test, and an ID difference in initial blur evaluation of 0.05. It is. Therefore, the toner of Comparative Example 11 has no problem with at least storage stability, low-temperature fixability, printing durability, and initial blur.
However, the toner of Comparative Example 11 has a large charge amount ratio of 2.21. The toner of Comparative Example 11 has a large LL fog value of 5.2. The toner of Comparative Example 11 has a large ID difference of 0.48 due to the environment. In addition, the toner of Comparative Example 11 has a large ID difference of 0.21 in evaluation of blur after durability.
Therefore, the toner of Comparative Example 11 which does not contain alumina fine particles and instead contains titanium oxide particles having a number average primary particle size of 15 nm is in a high temperature and high humidity (H / H) environment and a low temperature and low humidity (L / L) environment. It can be seen that there is a large difference in the performance below, and fog is likely to occur due to charge-up in a low-temperature, low-humidity (L / L) environment.

From Table 2, the toners of Comparative Examples 3 to 5 are toners containing only silica fine particles A and C, and alumina fine particles, and no silica fine particles B. From Table 4, the toners of Comparative Examples 3 to 5 have a charge amount ratio of 1.33 to 1.58, a minimum fixing temperature of 160 ° C., an LL fog value of 0.1 to 0.2, The difference in ID depending on the environment is 0.11 to 0.15, and the number of continuous prints in the print durability test is 14,000 or more. Therefore, the toners of Comparative Examples 3 to 5 have no problems in at least charging stability, low-temperature fixability, charging property in a low-temperature and low-humidity (L / L) environment, environmental stability, and printing durability.
However, the toners of Comparative Examples 3 to 5 have a maximum blocking amount of 4.5 g. This value is the largest among the toners of Examples 1 to 16 and Comparative Examples 1 to 11. In addition, the maximum ID difference in initial blur evaluation is 0.15, and the maximum ID difference in post-endurance scratch evaluation is 0.42. The value of the ID difference in the post-endurance evaluation of Comparative Example 4 is the largest among the toners of Examples 1 to 16 and Comparative Examples 1 to 11.
Therefore, it can be seen that the toners of Comparative Examples 3 to 5 that do not contain the silica fine particles B having a number average primary particle size of 15 to 35 nm are likely to be damaged particularly after durability.

From Table 2, the toners of Comparative Example 6 and Comparative Example 7 are toners containing only silica fine particles B and C, and alumina fine particles, and no silica fine particles A. From Table 4, the toners of Comparative Examples 6 and 7 have a minimum fixing temperature of 155 ° C. or 160 ° C. Therefore, the toners of Comparative Examples 6 and 7 have no problem with at least low-temperature fixability.
However, the toner of Comparative Example 6 has a large blocking amount of 2.8 g. In addition, the charge amount ratio is as large as 1.67. Further, as described above, in the evaluation of the “fogging LL environment” of Comparative Example 6 or the like, a printing defect occurs.
Therefore, the toners of Comparative Examples 6 to 7 which do not contain silica fine particles A having a number average primary particle size of 36 to 100 nm are inferior in storability and are in a high temperature and high humidity (H / H) environment and low temperature and low humidity (L / L) In addition to the large difference in charging performance under the environment, it can be seen that the printing performance is generally poor.

From Table 2, the toners of Comparative Example 8 and Comparative Example 9 are toners containing only silica fine particles A and B, and alumina fine particles, and not containing silica fine particles C. From Table 4, the toners of Comparative Example 8 and Comparative Example 9 each have a blocking amount of 0.2 g, the charge amount ratio is 1.33 or 1.41, the LL fog value is 0.2, and depends on the environment. The ID difference is 0.09 or 0.12, and the number of continuous prints in the print endurance test exceeds 15,000. Therefore, the toners of Comparative Example 8 and Comparative Example 9 have no problems in at least storage stability, charging stability, charging property in a low temperature and low humidity (L / L) environment, environmental stability, and printing durability.
However, in particular, the toner of Comparative Example 9 has a minimum fixing temperature as high as 180 ° C. This value is the highest among the toners of Examples 1 to 16 and Comparative Examples 1 to 11. Further, the maximum ID difference in the evaluation of initial blur is 0.28, and the ID difference in evaluation of blur after durability is 0.39. The value of the ID difference in the initial blur evaluation of Comparative Example 8 is the largest among the toners of Examples 1 to 16 and Comparative Examples 1 to 11.
Therefore, it can be seen that the toners of Comparative Example 8 and Comparative Example 9 that do not contain silica fine particles C having a number average primary particle size of 6 to 14 nm are inferior in low-temperature fixability, and are particularly susceptible to blurring at an early stage.

On the other hand, from Table 1, the toners of Examples 1 to 15 are toners containing both silica fine particles A to C and alumina fine particles having a number average primary particle size within a specific range. From Table 3, the toners of Examples 1 to 15 have a blocking amount of 1.0 g or less, a charge amount ratio of 1.82 or less, a minimum fixing temperature of 175 ° C. or less, and an LL fog value of 0.8 or less. The ID difference due to the environment is 0.25 or less, the number of continuously printed sheets in the printing durability test is 11,000 sheets or more, the ID difference in the initial blur evaluation is 0.13 or less, and the ID difference in the scratch evaluation after durability is 0.19 or less. It is.
Therefore, as the external additive, silica fine particles A having a number average primary particle size of 36 to 100 nm, silica fine particles B having a number average primary particle size of 15 to 35 nm, and silica fine particles having a number average primary particle size of 6 to 14 nm. The toners of Examples 1 to 15 containing C and alumina fine particles having a number average primary particle size of 5 to 100 nm have an excellent balance between low-temperature fixability and storage stability, and are in a normal temperature and normal humidity (N / N) environment. Excellent print durability at the bottom, very low initial and post-endurance blurring. Furthermore, since the difference in charge amount due to the environment is small, charge-up is suppressed even in a low-temperature and low-humidity (L / L) environment. It can be seen that the amount of toner is small.

Hereinafter, the influence of each content of the external additive of the toner on the toner characteristics will be examined.
First, Example 1 (content: 1.5 parts) and Example 2 (content: 2.5 parts), which differ only in the content condition of silica fine particles A, are compared. From Table 3, the toner of Example 2 has a slightly lower charge amount ratio but a slightly higher minimum fixing temperature than the toner of Example 1. From these results, it is presumed that the higher the content of the silica fine particles A, the smaller the difference in charging performance under different environments, but the lower the low-temperature fixability.
The content of silica fine particles B in Comparative Example 7 is equal to the sum of the contents of silica fine particles A and B in Example 1. As shown in Table 4, the toner of Comparative Example 7 is inferior in storage stability and printing durability. Therefore, it can be seen that even if the silica fine particles A in Example 1 are all replaced with the silica fine particles B, the toner characteristics deteriorate.

Next, Example 1 (content: 0.3 part), Example 4 (content: 0.1 part), and Example 11 (content: 1.5) differing only in the content condition of the silica fine particles B. Part) and Comparative Example 4 (content: 0 part). From Table 3, the toner of Example 4 has a slightly lower minimum fixing temperature than the toner of Example 1, but the difference in ID depending on the charge amount ratio and the environment is slightly larger. Scratch is also likely to occur, and the printing durability is slightly inferior. Further, the toner of Example 11 has a smaller charge amount ratio than the toner of Example 1, but the minimum fixing temperature is slightly higher. From these results and the examination of Comparative Example 4 described above, the smaller the content of the silica fine particles B, the better the low-temperature fixability, but the initial and post-durability is somewhat likely to occur and the printing durability is somewhat inferior. Guessed. From these results, it is presumed that the higher the content of the silica fine particles B, the smaller the difference in charge amount under different environments, but the lower the low-temperature fixability.
The content of silica fine particles A in Comparative Example 3 is substantially equal to the sum of the contents of silica fine particles A and B in Example 1. As shown in Table 4, the toner of Comparative Example 3 is liable to be blurred after endurance.
Further, the content of the silica fine particles C in Comparative Example 5 is equal to the sum of the contents of the silica fine particles B and C in Example 1. As shown in Table 4, the toner of Comparative Example 5 is extremely inferior in storage stability, poor in printing durability, and is liable to cause blurring after durability.
Therefore, it can be seen that even if the silica fine particles B in Example 1 are all replaced with the silica fine particles A or C, the toner characteristics deteriorate.

Subsequently, Example 1 (content: 0.2 part), Example 5 (content: 0.4 part), and Example 6 (content: 0.1) differing only in the content condition of the silica fine particles C. Part) and Comparative Example 8 (content: 0 part). From Table 3, the toner of Example 5 has a slightly lower minimum fixing temperature than the toner of Example 1. In addition, the toner of Example 6 is slightly superior in low-temperature fixability as compared with the toner of Example 1, but the ratio of the charge amount is slightly large, and the initial and post-endurance blur is likely to occur somewhat. From these results, it is presumed that the higher the content of the silica fine particles C, the lower the low-temperature fixability. In addition, from these results and the examination of Comparative Example 8 described above, the lower the content of the silica fine particles C, the better the low-temperature fixability, but the difference in charging performance under different environments is slightly widened, and blurring is likely to occur. Guessed.
The content of silica fine particles B in Comparative Example 9 is twice the sum of the contents of silica fine particles B and C in Example 1. As shown in Table 4, the toner of Comparative Example 9 is inferior in low-temperature fixability and is liable to cause blurring at the initial stage and after durability. Therefore, it can be seen that even if the silica fine particles C in Example 1 are all replaced with the silica fine particles B, the toner characteristics deteriorate.

Next, Example 1 (content: 0.5 part), Example 7 (content: 1.5 parts), and Example 8 (content: 0.1 parts) differing only in the content of alumina fine particles. ) And Comparative Example 1 (content: 0 part). From Table 3, the toner of Example 7 has a slightly lower minimum fixing temperature than the toner of Example 1. Further, the toner of Example 8 is slightly superior to the toner of Example 1 in terms of low-temperature fixability, but the ID difference depending on the charge amount ratio and the environment is slightly larger. From these results, it is estimated that the higher the content of the alumina fine particles, the lower the low-temperature fixability. Further, from these results and the examination of Comparative Example 1 described above, it is presumed that the lower the content of alumina fine particles, the better the low-temperature fixability, but the difference in charging performance under different environments is somewhat widened.
The content of silica fine particles B in Comparative Example 2 is equal to the sum of the contents of silica fine particles B and alumina fine particles in Example 1. As shown in Table 4, the toner of Comparative Example 2 has a large ID difference due to the charge amount ratio and the environment, and a high LL fog value. Therefore, it can be seen that even if the alumina fine particles in Example 1 are all replaced with the silica fine particles B, the toner characteristics are deteriorated.

  Finally, Example 1 (number average primary particle size: 18 nm), Example 9 (number average primary particle size: 65 nm), and Comparative Example 10 (number average primary) differing only in the condition of the number average primary particle size of the alumina fine particles. Particle size: 200 nm). From Table 3, the toner of Example 9 is slightly larger in the charge amount ratio and the ID difference depending on the environment than the toner of Example 1. From these results and the examination of Comparative Example 10 described above, it is presumed that the larger the number average primary particle size of the alumina fine particles, the larger the difference in charging performance under different environments.

Claims (4)

In the toner for electrostatic charge development containing the colored resin particles containing the binder resin and the colorant, and the external additive,
As an external additive,
Silica fine particles A having a number average primary particle size of 36 to 100 nm,
Silica fine particles B having a number average primary particle size of 15 to 35 nm,
A toner for developing an electrostatic charge image, comprising silica fine particles C having a number average primary particle size of 6 to 14 nm and alumina fine particles having a number average primary particle size of 5 to 75 nm .   2. The electrostatic image developing toner according to claim 1, wherein the total content of the external additive is 1.7 to 3.6 parts by mass with respect to 100 parts by mass of the colored resin particles.   The static content according to claim 1 or 2, wherein the total content of silica fine particles A to C in the external additive is 1.6 to 3.0 parts by mass with respect to 100 parts by mass of the colored resin particles. Toner for charge image development. As an external additive with respect to 100 parts by mass of the colored resin particles,
0.5 to 2.9 parts by mass of the silica fine particles A,
0.1 to 2.0 parts by mass of the silica fine particles B,
The electrostatic charge image according to claim 1, comprising 0.05 to 0.5 parts by mass of the silica fine particles C and 0.05 to 2 parts by mass of the alumina fine particles. Developing toner.