JP5668465B2 - Toner for electrostatic image development - Google Patents

Description

  The present invention relates to an electrostatic image developing toner (hereinafter, sometimes simply referred to as “toner”) that is excellent in environmental stability and does not generate fog even in a high temperature and high humidity environment.

  The process of adhering silica fine particles (hereinafter sometimes simply referred to as “silica”) to the toner surface in toner production is generally referred to as external addition, which ensures fluidity and adds storage stability at high temperatures. It is generally performed for such purposes. In recent years, since the toner has become low-temperature fixing and the toner is designed to be easily melted, the storage stability at a high temperature has become an issue.

In general, silica particles used for external addition have different effects depending on the particle size.
Silica fine particles with a small primary particle size have a large surface area and cover a large amount of toner, contributing greatly to improving fluidity. Silica fine particles with a large primary particle size act as spacers between the toners, so that storage stability and silica embedding can be achieved. Greatly contributes to suppression. Therefore, these are generally used in combination.

  As described above, external addition of silica fine particles to the toner has a great effect, but also has some adverse effects. First, since the toner surface is covered, the fixability when the toner is actually printed by a printer is adversely affected. The toner after the external addition is not fixed unless the temperature is higher than the toner before the external addition. In particular, in the case of positively chargeable toner, the silica fine particles themselves exhibit negative chargeability, and thus can be relaxed by surface treatment or the like. However, if the toner is coated with more silica, the charge amount of the toner may be reduced. .

  Further, it is known that when the toner is stirred for charging during image formation, a phenomenon occurs in which silica is buried in the toner and the toner charge amount is reduced. Such a decrease in the toner charge amount becomes worse as the silica coverage on the toner increases. For this reason, it is desirable to provide a toner fluidity improvement effect and a storage stability improvement effect with a smaller coverage.

  Furthermore, when silica adheres to the toner non-uniformly due to high silica cohesiveness, the initial toner charge amount becomes unstable or the toner charge amount decreases over time. Is seen. These phenomena are also unfavorable because they may cause toner malfunction in the printer.

  Patent Document 1 discloses a method for producing an amino group-containing inorganic powder, characterized in that a disiloxane compound having a specific structure is brought into contact with an inorganic powder having a hydroxyl group on the surface at a temperature of 80 ° C. or higher. Yes.

  In Patent Document 2, it is surface-coated silica coated with two or more types of different silicone oils, and the amount of silicone oil extracted with chloroform is 5 to 95% by mass of the total silicone oil coated, And the surface-coated silica characterized in that at least one silicone oil is not contained in the extracted silicone oil is disclosed.

JP 2006-321844 A JP 2007-176747 A

The inorganic powder obtained by the production method disclosed in Patent Document 1 is not designed from the viewpoint of improving the durability of the toner. Therefore, Patent Document 1 discloses positive chargeability for electrostatic image development. An external additive formulation for improving the storage stability of the toner is not disclosed.
Further, the surface-coated silica disclosed in Patent Document 2 does not mention the balance between positive chargeability and hydrophobicity, and does not disclose a formulation that provides toner stability in a high temperature and high humidity environment.

  An object of the present invention is to improve the storage stability of toner at high temperatures. Disclosed is a toner for developing an electrostatic image, which has excellent printing characteristics, does not cause a decrease in charge amount due to an external additive, and has high storage stability in a printer.

  As a result of intensive studies to solve the above problems, the present inventor used a specific amount of a specific treatment agent when hydrophobizing hydrophilic silica fine particles having a specific BET specific surface area, and derived from the surface treatment agent. It has been found that the above-mentioned problems can be solved by controlling the carbon content and nitrogen content.

That is, according to the present invention, in the electrostatic charge image developing toner containing the colored resin particles containing the binder resin and the colorant and the external additive, the external additive contains the silica fine particles (A), The silica fine particles (A) are obtained by hydrophobizing silica fine particles (S) having a BET specific surface area of 70 to 200 (m ² / g) with a silicon compound , and the following formulas (1) and (2) And 0.4 to 2.0 parts by mass are added to 100 parts by mass of the colored resin particles.

  In the present invention, the amount of adsorbed moisture of the silica fine particles (A) is preferably 0.1 to 0.7% by mass.

  In the present invention, the external additive further contains silica fine particles (B) having a number average primary particle size of 5 to 14 nm, and the silica fine particles (B) are added to 0 part by mass of the colored resin particles. 0.05 to 3 parts by mass are preferably added.

  In the present invention, the external additive further contains a silica fine particle (C) having a number average primary particle size of 35 to 200 nm, and the silica fine particle (C) is 0 with respect to 100 parts by mass of the colored resin particles. 0.05 to 3 parts by mass are preferably added.

  In the present invention, the colored resin particles preferably contain a positively chargeable charge control agent, have a volume average particle diameter of 4 to 12 μm, and an average circularity of 0.96 or more.

  According to the toner for developing an electrostatic charge image of the present invention as described above, stable chargeability is exhibited over time regardless of temperature conditions and humidity conditions, and deterioration of image quality due to fog or the like even when continuous printing of a large number of sheets is performed. Therefore, it is possible to provide a toner that is less likely to occur and has excellent storage stability.

The toner for developing an electrostatic charge image of the present invention is a toner for developing an electrostatic charge image containing a colored resin particle containing a binder resin and a colorant and an external additive. The external additive contains silica fine particles (A). And the silica fine particles (A) are obtained by surface-treating silica fine particles (S) having a BET specific surface area of 70 to 200 (m ² / g) with a surface treatment agent, and the following formula (1) and It satisfies the formula (2) and is added in an amount of 0.4 to 2.0 parts by mass with respect to 100 parts by mass of the colored resin 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 silica fine particles (A) satisfying specific conditions as an external additive.
The toner of the present invention is preferably obtained by adhering and adding the silica fine particles (A) as an external additive to the surface of the colored resin particles.
Hereinafter, a method for producing colored resin particles used in the present invention, a colored resin particle obtained by the production method, a method for producing the toner of the present invention using the colored resin particles and silica fine particles (A), and the toner of the present invention Will be described in order.

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

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

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

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

  In the present invention, the polymerizable monomer means a monomer having a polymerizable functional group, and the polymerizable monomer is polymerized to become a binder resin. It is preferable to use a monovinyl monomer as the main component of the polymerizable monomer. Examples of the monovinyl monomer include styrene; styrene derivatives such as vinyl toluene and α-methylstyrene; acrylic acid and methacrylic acid; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, acrylic acid 2 Acrylic esters such as ethylhexyl and dimethylaminoethyl acrylate; methacrylic esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate and dimethylaminoethyl methacrylate; acrylonitrile And nitrile compounds such as methacrylonitrile; amide compounds such as acrylamide and methacrylamide; olefins such as ethylene, propylene, and butylene. These monovinyl monomers can be used alone or in combination of two or more. Of these, styrene, styrene derivatives, and acrylic 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; Examples include ester compounds in which two or more carboxylic acids are ester-bonded; other divinyl compounds such as N, N-divinylaniline and divinyl ether; compounds having three or more vinyl groups. These crosslinkable polymerizable monomers can be used alone or in combination of two or more.
In the present invention, the crosslinkable polymerizable monomer is usually used at a ratio of 0.1 to 5 parts by mass, preferably 0.3 to 2 parts by mass with respect to 100 parts by mass of the monovinyl monomer. desirable.

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

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

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

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

  As the magenta colorant, monoazo pigments, azo pigments such as disazo pigments, and compounds such as condensed polycyclic pigments are used. I. Pigment Red 31, 48, 57: 1, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 149, 150, 163, 170, 184, 185, 187, 202, 206, 207, 209, 213, 237, 251, 269 and C.I. I. Pigment violet 19 and the like.

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

  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 an ester wax and / or a 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 pentaerythrole tetrapalinate, pentaerythrole tetrabehenate, pentaerythrole tetrastearate, etc. Pentaerythritol ester compound; hexaglycerin tetrabehenate tetrapalinate, hexaglycerin octabehenate, pentaglycerin heptabehenate, tetraglycerin hexabehenate, triglycerin pentabehenate, diglycerin tetrabehenate, Glycerin ester compounds such as glycerin tribehenate; dipentaerythritol ester compounds such as dipentaerystol hexamilitate and dipentaerystol hexapalinate; Glycerin ester compounds are preferred, hexaglycerin tetrabehenate tetrapalinate, hexaglycerin octabehenate, tetraglycerin hexabehenate, and triglycerin pentabehenate are more preferred, and hexaglycerin octabehenate is particularly preferred. preferable.

  The acid value of the ester wax is preferably 2 mgKOH / g or less, more preferably 1 mgKOH / g or less, and further preferably 0.5 mgKOH / g or less. In addition, the acid value of ester wax is a value measured based on JOCS 2.3.1-96 using the standard oil-fat analysis method established by Japan Oil Chemical Association (JOCS).

  When the acid value of the ester wax exceeds the upper limit, an unreacted monovalent fatty acid-derived carboxylic acid group remains in the ester wax. It becomes difficult to stably form droplets of the composition, which adversely affects the particle size characteristics of the colored resin particles, easily deteriorates the image quality due to fog, etc., and promotes the generation of volatile substances during fixing. May cause odor.

  In the present invention, the hydroxyl value of the ester wax is preferably 15 mgKOH / g or less, more preferably 10 mgKOH / g or less, and further preferably 5 mgKOH / g or less. In addition, the hydroxyl value of ester wax is a value measured based on JOCS 2.3.6.2-96, using the standard oil analysis test method established by Japan Oil Chemical Association (JOCS).

  In the case where the hydroxyl value of the ester wax exceeds the upper limit, hydroxyl groups derived from unreacted raw materials remain in the ester wax. It may be difficult to form a stable color, adversely affect the particle size characteristics of the colored resin particles, and image quality may be deteriorated due to fog or the like.

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.

  The above-mentioned “petroleum-based wax” refers to a solid that is produced from a petroleum refining process and is solid at room temperature mainly composed of a saturated hydrocarbon having a side chain. In JIS K 2235, paraffin wax, microstalline wax, and There are three main types of petratum. In the present invention, it is preferable to select at least one of these three types and use it as a component of the release agent. Among petroleum waxes, paraffin wax and microstalline wax are more preferable from the viewpoint of achieving a good balance between low-temperature fixability and storage stability of the toner.

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 More preferably used.
Examples of positively chargeable charge control agents include nigrosine dyes, quaternary ammonium salts, triaminotriphenylmethane compounds and imidazole compounds, polyamine resins as charge control resins that are preferably used, and quaternary ammonium group-containing copolymers. , And quaternary ammonium base-containing copolymers.
Negatively chargeable charge control agents include azo dyes containing metals such as Cr, Co, Al, and Fe, salicylic acid metal compounds and alkylsalicylic acid metal compounds, and sulfonic acid group containing charge control resins that are preferably used Examples thereof include a copolymer, a sulfonate group-containing copolymer, a carboxylic acid group-containing copolymer, and a carboxylic acid group-containing copolymer.
In the present invention, the charge control agent is usually used in a proportion of 0.01 to 10 parts by mass, preferably 0.03 to 8 parts by mass, with respect to 100 parts by mass of the monovinyl monomer. If the addition amount of the charge control agent is less than 0.01 parts by mass, fog may occur. On the other hand, when the addition amount of the charge control agent exceeds 10 parts by mass, printing stains may occur.

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

(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, a polymerization initiator is added, and then the polymerizable monomer composition is added. Form droplets of objects. The method for forming droplets is not particularly limited. For example, (in-line type) emulsifying disperser (trade name “Milder” manufactured by Ebara Seisakusho Co., Ltd.), high-speed emulsifying disperser (made by Tokushu Kika Kogyo, trade name “TK”). .. Homomixer MARK type II)) etc.

  As a polymerization initiator, persulfates such as potassium persulfate and ammonium persulfate: 4,4′-azobis (4-cyanovaleric acid), 2,2′-azobis (2-methyl-N- (2- Hydroxyethyl) propionamide), 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis (2,4-dimethylvaleronitrile), and 2,2′-azobisisobutyro Azo compounds such as nitrile; di-t-butyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylbutanoate, diisopropyl peroxydicarbonate, Organic peroxides such as di-t-butylperoxyisophthalate and t-butylperoxyisobutyrate It is. 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 polymerized toner can reproduce an image clearly and does not deteriorate environmental stability.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  In the present invention, the circularity is defined as a value obtained by dividing the circumference of a circle having the same projected area as the particle image by the 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.

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

3. Production Method of Toner of the Present Invention Colored resin particles are obtained by mixing and stirring the colored resin particles obtained by the above-described (A) polymerization method or (B) pulverization method with external additives such as silica fine particles (A) described later. Can be uniformly and suitably added (externally added) to the surface.

A method for adding (externally adding) an external additive such as silica fine particles (A) described later to the surface of the colored resin particles is not particularly limited, and can be performed using an apparatus capable of mixing and stirring.
As an apparatus capable of mixing and stirring, for example, Henschel mixer (: trade name, manufactured by Mitsui Mining), Super mixer (: trade name, manufactured by Kawada Manufacturing), Q mixer (: trade name, manufactured by Mitsui Mining), Typical examples include a high-speed stirrer such as a mechanofusion system (trade name, manufactured by Hosokawa Micron Corporation), mechano mill (trade name, manufactured by Okada Seiko Co., Ltd.), and nobilta (: trade name, manufactured by Hosokawa Micron Corporation).

The toner of the present invention contains silica fine particles (A) as an external additive.
The silica fine particles (A) used in the present invention are obtained by surface-treating silica fine particles (S) having a BET specific surface area of 70 to 200 (m ² / g) with a surface treatment agent, and the silica fine particles ( A value obtained by dividing the carbon content (% by mass) of A) by the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment is 3.5 × 10 ^{−2 to} 5.5 × 10. ⁻² and a value obtained by dividing the nitrogen content (% by mass) of the silica fine particles (A) by the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment was 2. 0 × a ^{10 -3 ~4.0} × ¹⁰ -3, and the silica fine particles (a), relative to 100 parts by weight of the colored resin particles are added 0.4 to 2.0 parts by weight.

BET specific surface area of the silica fine particles before the surface treatment (S) is preferably 90~180 ^(m 2 / g), more preferably 110~150 ^(m 2 / g).
If the BET specific surface area before the surface treatment is less than 70 (m ² / g), the durability and storage stability may be lowered. Conversely, if the BET specific surface area is greater than 200 (m ² / g), There is a risk that fogging may occur due to a decrease in charge amount.

The value obtained by dividing the carbon content (% by mass) of the silica fine particles (A) by the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment is the silica fine particles (A ), And the value is preferably 3.7 × 10 ^{−2 to} 5.3 × 10 ⁻² , and preferably 4.0 × 10 ^{−2 to} 4.8 × 10 ^−2. It is more preferable that
If this value is less than 3.5 × 10 ⁻² , the amount of charge in a high-temperature and high-humidity environment may decrease, and fogging may occur. Conversely, if it is greater than 5.5 × 10 ⁻² , negative chargeability may occur. There is a risk that fogging may occur due to a decrease in charge even in a room temperature and humidity environment.

The value obtained by dividing the nitrogen content (% by mass) of the silica fine particles (A) by the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment is the silica fine particles (A ) of equivalent to positively charged index, the value is preferably ^{2.2 × 10 -3 ~3.5 × 10 -3} , 2.5 × 10 -3 ~3.3 × 10 - ³ is more preferable.
If this value is less than 2.0 × 10 ⁻³ , the charge amount in a high-temperature and high-humidity environment may decrease, and fogging may occur. Conversely, if the value is greater than 4.0 × 10 ⁻³ , the hydrophobicity of silica And the charge amount in a high temperature and high humidity environment may be reduced.

  The addition amount of the silica fine particles (A) is preferably 0.5 to 1.8 parts by mass and more preferably 0.6 to 1.6 parts by mass with respect to 100 parts by mass of the colored resin particles. If the amount added is less than 0.4 parts by mass, the amount of charge in a high-temperature and high-humidity environment may decrease, and fogging may occur. Conversely, if the amount added exceeds 2.0 parts by mass, the toner fixability is deteriorated. There is a fear.

  The carbon content in the silica fine particles (A) can be measured by a high-frequency heating infrared absorption method, the nitrogen content can be measured by an ammonia distillation separation amide sulfate titration method (Kjeldahl method), etc. . Specifically, the carbon and nitrogen content can be measured by a total nitrogen / total carbon measuring device (SUMIGANCNC-22, manufactured by Sumika Chemical Analysis Center Co., Ltd.), and the carbon content can be measured by a metal carbon / sulfur analyzer (Horiba, Ltd.). Nitrogen content can be measured with a metal oxygen / nitrogen analyzer (Horiba, EMGA620-W), a nitrogen / oxygen analyzer (LECO), etc.

The amount of adsorbed moisture of the silica fine particles (A) is preferably 0.1 to 0.7% by mass, when the total mass of the silica fine particles (A) is 100% by mass, and 0.1 to 0. It is more preferably 5% by mass, and further preferably 0.2 to 0.4% by mass. When the amount of adsorbed moisture of the silica fine particles (A) exceeds the above range, the chargeability may be lowered or filming on the photoconductor may occur.
The amount of moisture adsorbed on the silica fine particles (A) can be measured by an adsorption / desorption measurement device, a continuous vapor adsorption device, or the like.

The silica fine particles (A) used as an external additive in the present invention are those obtained by surface-treating silica fine particles (S) with a surface treatment agent, preferably those obtained by hydrophobizing silica fine particles (S) with a silicon compound. Yes, more preferably, silica fine particles (S) are hydrophobized with two or more silicon compounds. In this case, in order to impart high positive chargeability, at least one of the silicon compounds is an amino group-containing silicon compound, and at least one other is a silicon compound not containing an amino group. Is preferred.
Among these silicon compounds, the silicon compound containing an amino group mainly imparts positive chargeability to the silica fine particles (A), and the silicon compound not containing an amino group is mainly hydrophobic to the silica fine particles (A). Take the role of granting.

  As the silicon compound containing an amino group, various compounds can be used without any particular restriction. For example, an amino group-containing silane coupling agent, an amino-modified silicone oil, a quaternary ammonium salt type silane. Etc. can be used. Among these, an amino group-containing silane coupling agent is particularly preferable from the viewpoints of ability to impart positive chargeability and fluidity. Specific examples of the amino group-containing silane coupling agent include, for example, N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, 3-aminopropyl. Trimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, and the like can be mentioned. Among them, the effect of improving the environmental stability of charging performance is excellent, which is preferable. Is preferably a coupling agent having an aminoalkyl group, particularly preferably 3-aminopropyltriethoxysilane.

  On the other hand, as the silicon compound not containing an amino group, various compounds can be used without any particular limitation as long as they do not contain an amino group and express hydrophobicity. From the viewpoint of fluidity, for example, alkoxysilane, a silane coupling agent not containing an amino group, silazane, silicone oil, silicone resin, and the like are preferable, and alkoxysilane, silicone oil, and silicone resin are particularly preferable. Examples of the alkoxysilane include isobutyltrimethoxysilane, octyltriethoxysilane, and trifluoropropyltrimethoxysilane. Examples of the silicone oil include straight silicone oil such as dimethylpolysiloxane and methylhydrogenpolysiloxane. And modified silicone oils such as epoxy-modified silicone oil and fluorine-modified silicone oil. Examples of the silicone resin include trimethylsiloxysilicic acid.

In the present invention, the external additive preferably further contains silica fine particles (B) having a number average primary particle size of 5 to 14 nm in addition to the silica fine particles (A). The number average primary particle size of the silica fine particles (B) is more preferably 7 to 12 nm. The silica fine particles (B) are preferably fumed silica.
When the number average primary particle size of the silica fine particles (B) is less than 5 nm, the silica fine particles are easily embedded from the surface to the inside of the colored resin particles, and sufficient fluidity is 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 14 nm, the proportion (coverage) of the silica fine particles (B) with respect to the surface of the toner particles decreases, so May not be sufficiently imparted to the toner particles, and the storage stability of the toner may be reduced.

In the present invention, the external additive preferably further contains silica fine particles (C) having a number average primary particle size of 35 to 200 nm. The number average primary particle size of the silica fine particles (C) is more preferably 35 to 120 nm, still more preferably 40 to 80 nm, and particularly preferably 40 to 60 nm.
When the number average primary particle size of the silica fine particles (C) is less than 35 nm, the spacer effect is lowered, and the silica fine particles are easily embedded from the surface of the colored resin particles into a suitable flow over time. The toner cannot be imparted with toner properties, which may adversely affect printing performance. On the other hand, when the number average primary particle size of the silica fine particles (C) exceeds 200 nm, the silica fine particles (C) are easily released from the surface of the toner particles, and the function as an external additive is reduced. May adversely affect printing performance.

The content of the silica fine particles (B) is preferably 0.05 to 3 parts by mass, more preferably 0.1 to 2 parts by mass, with respect to 100 parts by mass of the colored resin particles. More preferably, it is -1 mass part.
The content of the silica fine particles (C) is preferably 0.05 to 3 parts by mass, more preferably 0.2 to 2 parts by mass with respect to 100 parts by mass of the colored resin particles. More preferably, it is -1.5 mass parts.
When the content of the silica fine particles (B) is less than 0.05 parts by mass, the function as an external additive cannot be sufficiently exhibited, the fluidity is lowered, and the storage stability and durability are lowered. There is a risk of doing so. On the other hand, when the content of the silica fine particles (B) exceeds 3 parts by mass, the silica fine particles (B) are easily liberated from the surface of the toner particles, and the chargeability in a high temperature and high humidity environment decreases. Fog may occur.
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 printing performance may be adversely affected. On the other hand, when the content of the silica fine particles (C) exceeds 3 parts by mass, the silica fine particles (C) are easily released from the surface of the toner particles, the function as an external additive is reduced, and the printing performance is reduced. May be adversely affected.

  As the silica fine particles (B), various commercially available products can be used. For example, HDK2150 manufactured by Clariant (: trade name, number average primary particle size: 12 nm); R504 (: trade name, manufactured by Nippon Aerosil Co., Ltd.) Number average primary particle size: 12 nm), RA200HS (: trade name, number average primary particle size: 12 nm); MSP-012 (: trade name, number average primary particle size: 16 nm), MSP-013 (: Product name, number average primary particle size: 12 nm), TG820F manufactured by Cabot Corporation (: product name, number average primary particle size: 7 nm); and the like.

  Various commercially available products can be used as the silica fine particles (C). For example, NA50Y (: trade name, number average primary particle size: 35 nm), VPNA50H (: trade name, number average primary particle) manufactured by Nippon Aerosil Co., Ltd. Diameter: 40 nm); H05TA manufactured by Clariant (trade name, number average primary particle diameter: 50 nm);

  In the present invention, the silica fine particles (B) and the silica fine particles (C) preferably contained in the external additive are preferably subjected to a hydrophobic treatment. As the hydrophobizing agent, for example, a silane coupling agent and a silicone oil similar to those that can be used for the hydrophobizing treatment of silica fine particles (A) can be used. Two or more types can be used in combination.

4). Toner of the Present Invention The toner of the present invention obtained through the above-described steps includes, as an external additive, the conditions of the BET specific surface area of the silica fine particles (S) before the surface treatment, and the above formulas (1) and (2). By including 0.4 to 2.0 parts by mass of the silica fine particles (A) satisfying any of the above with respect to 100 parts by mass of the colored resin particles, stable chargeability is exhibited over time regardless of temperature and humidity conditions. However, even when continuous printing of a large number of sheets is performed, image quality deterioration due to fog or the like hardly occurs, and storage stability is excellent.

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 silica fine particles (A) [Production Example 1]
The silica fine particles (S) before the surface treatment are fine particles produced by flame hydrolysis of a silicon halide compound, and fumed silica having a specific surface area of 130 m ² / g measured by a nitrogen adsorption method (BET method). Fine particles (manufactured by Nippon Aerosil Co., Ltd., trade name: “Aerosil 130”) were used.
100 parts of silica fine particles having a BET specific surface area of 130 m ² / g were put into a reaction vessel, and 4.5 parts of water were sprayed with stirring in a nitrogen atmosphere. To this, 30 parts of dimethylpolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KF-96-100cs”) and 3 parts of 3-aminopropyltrimethoxysilane are sprayed, heated and stirred at 150 ° C. for 1 hour, then cooled, Silica fine particles 1 were produced.

[Production Example 2]
As shown in Table 1, silica fine particles 2 were produced in the same manner as in Production Example 1 except that the amount of dimethylpolysiloxane added in Production Example 1 was changed from 30 parts to 22 parts.

[Production Example 3]
As shown in Table 1, in Production Example 1, fumed silica fine particles having a BET specific surface area of 130 m ² / g (manufactured by Nippon Aerosil Co., Ltd., trade name: “Aerosil 130”) were fumed silica having a BET specific surface area of 90 m ² / g. To fine particles (made by Nippon Aerosil Co., Ltd., trade name: “Aerosil 90”), the addition amount of dimethylpolysiloxane is changed from 30 parts to 22 parts, and the addition amount of 3-aminopropyltrimethoxysilane is changed from 3 parts to 2.2 parts. Except for the change, the silica fine particles 3 were produced in the same manner as in Production Example 1.

[Production Example 4]
As shown in Table 1, in Production Example 1, fumed silica fine particles having a BET specific surface area of 130 m ² / g (manufactured by Nippon Aerosil Co., Ltd., trade name: “Aerosil 130”) were fumed silica having a BET specific surface area of 90 m ² / g. Silica fine particles in the same manner as in Production Example 1, except that the amount of 3-aminopropyltrimethoxysilane added was changed from 3 parts to 1.5 parts to fine particles (manufactured by Nippon Aerosil Co., Ltd., trade name: “Aerosil 90”). 4 was produced.

[Production Example 5]
As shown in Table 1, in Production Example 1, fumed silica fine particles having a BET specific surface area of 130 m ² / g (manufactured by Nippon Aerosil Co., Ltd., trade name: “Aerosil 130”) were fumed silica having a BET specific surface area of 90 m ² / g. To fine particles (made by Nippon Aerosil Co., Ltd., trade name: “Aerosil 90”), the addition amount of dimethylpolysiloxane is changed from 30 parts to 18 parts, and the addition amount of 3-aminopropyltrimethoxysilane is changed from 3 parts to 1.5 parts. Except for the change, the silica fine particles 5 were produced in the same manner as in Production Example 1.

[Production Example 6]
As shown in Table 1, in Production Example 1, fumed silica fine particles having a BET specific surface area of 130 m ² / g (manufactured by Nippon Aerosil Co., Ltd., trade name: “Aerosil 130”) were fumed silica having a BET specific surface area of 90 m ² / g. To fine particles (product name: “Aerosil 90” manufactured by Nippon Aerosil Co., Ltd.), 30 parts of dimethylpolysiloxane is added to 30 parts of hexamethyldisilazane, and the addition amount of 3-aminopropyltrimethoxysilane is changed from 3 parts to 2.2 parts. Except for the change, the silica fine particles 6 were produced in the same manner as in Production Example 1.

[Production Example 7]
As shown in Table 1, in Production Example 1, fumed silica fine particles having a BET specific surface area of 130 m ² / g (manufactured by Nippon Aerosil Co., Ltd., trade name: “Aerosil 130”) were fumed silica having a BET specific surface area of 90 m ² / g. Except for changing to fine particles (Nippon Aerosil Co., Ltd., trade name: “Aerosil 90”), adding 30 parts of dimethylpolysiloxane and changing the addition amount of 3-aminopropyltrimethoxysilane from 3 parts to 6 parts. In the same manner as in Production Example 1, silica fine particles 7 were produced.

[Production Example 8]
As shown in Table 1, in Production Example 1, the addition amount of dimethylpolysiloxane was changed from 30 parts to 22 parts, and 3 parts of 3-aminopropyltrimethoxysilane was not added. Thus, silica fine particles 8 were produced.

[Production Example 9]
As shown in Table 1, Production Example 1 except that the addition amount of dimethylpolysiloxane was changed from 30 parts to 45 parts and the addition amount of 3-aminopropyltrimethoxysilane was changed from 3 parts to 5 parts in Production Example 1. In the same manner as in Example 1, silica fine particles 9 were produced.

[Production Example 10]
As shown in Table 1, in Production Example 1, fumed silica fine particles having a BET specific surface area of 130 m ² / g (manufactured by Nippon Aerosil Co., Ltd., trade name: “Aerosil 130”) were fumed silica having a BET specific surface area of 300 m ² / g. To fine particles (made by Nippon Aerosil Co., Ltd., trade name: “Aerosil 300”), the addition amount of dimethylpolysiloxane was changed from 30 parts to 90 parts, and the addition amount of 3-aminopropyltrimethoxysilane was changed from 3 parts to 10 parts. Except for the above, silica fine particles 10 were produced in the same manner as in Production Example 1.

2. 2. Evaluation of external additives 2-1. Measurement of BET specific surface area The BET specific surface area is a fully-automatic BET specific surface area measuring device (trade name: manufactured by Mountec Co., Ltd.) for the silica fine particle raw materials used in Production Examples 1 to 10, ie, silica fine particles before surface treatment. Using “Macsorb HM model-1208”), measurement was performed by a nitrogen adsorption method (BET method).

2-2. Carbon content and nitrogen content For the above silica fine particles 1-10, the carbon content of each silica fine particle was analyzed using a metal carbon / sulfur analyzer (Horiba Seisakusho, EMIA-2200 type) for metal oxygen / nitrogen analysis. The nitrogen content of each silica fine particle was measured using an apparatus (Horiba Seisakusho, EMGA620-W).

2-3. Measurement of Adsorbed Moisture Amount of adsorbed moisture was measured for the silica fine particles 1 to 10 using a moisture absorption / desorption measuring device (trade name: “IGAsorp” manufactured by Nippon Sibel Hegner).
The sample silica fine particles are left in the apparatus in a nitrogen stream for 1 hour, and then moisture is adsorbed in air at a temperature of 32 ° C. and a humidity of 80% for 1 hour to adsorb (increased mass / sample mass) × 100. The amount of water.

  The measurement and evaluation results of the silica fine particles 1 to 10 are shown in Table 1 together with the type and addition amount of the surface treatment agent.

3. Production and evaluation of colored resin particles 81 parts of styrene and 19 parts of n-butyl acrylate as a polymerizable monomer, and 5 parts of carbon black (trade name: # 25B, manufactured by Mitsubishi Chemical Corporation) as a black colorant A polymerizable monomer mixture was obtained by dispersing using a machine (manufactured by Ebara Seisakusho, trade name: Ebara Milder).
In the above polymerizable monomer mixture, 1 part of a charge control resin (manufactured by Fujikura Kasei Co., Ltd., trade name “Acrybase FCA-161P”) as a charge control agent, and fatty acid ester wax (manufactured by Nippon Oil & Fats Co., Ltd., trade name) as a release agent “WEP3”) 5 parts, polymethacrylic acid ester macromonomer (manufactured by Toa Gosei Chemical Co., Ltd., trade name “AA6”, Tg = 94 ° C.) 0.3 part as a macromonomer, divinylbenzene 0. 6 parts and 1.6 parts of t-dodecyl mercaptan as a molecular weight modifier 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. 6 parts of t-butylperoxy-2-ethylhexanoate (manufactured by NOF Corporation, trade name: Perbutyl O) was added thereto as a polymerization initiator, and then an in-line type emulsifier / disperser (trade name, manufactured by Ebara Corporation). : Ebara Milder) was dispersed by high-speed shearing and stirring at a rotational speed of 15,000 rpm for 10 minutes to form droplets of the polymerizable monomer composition.

  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) 0.3 part of 2-methyl-N- (2-hydroxyethyl) -propionamide) (manufactured by Wako Pure Chemical Industries, Ltd., trade name: VA-086, water-soluble) was added, and the reaction was continued at 90 ° C. for 4 hours. Thereafter, the reaction was stopped by cooling with water to obtain an aqueous dispersion of colored resin particles having a core-shell structure.

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

The obtained colored resin particles were examined for volume average particle size (Dv), number average particle size (Dn), and particle size distribution (Dv / Dn).
About 0.1 g of a measurement sample (colored resin particles) was weighed and taken in a beaker, and 0.1 mL of an alkylbenzenesulfonic acid aqueous solution (trade name: Drywell, manufactured by Fuji Film Co., Ltd.) was added as a dispersant. 10-30 mL of Isoton II is further added to the beaker, and dispersed for 3 minutes with a 20 W (Watt) ultrasonic disperser. Then, using a particle size analyzer (Beckman Coulter, trade name: Multisizer). , Aperture diameter: 100 μm, medium: Isoton II, number of measured particles: volume average particle diameter (Dv) and number average particle diameter (Dn) of the colored resin particles were measured under the conditions of 100,000 particles. Distribution (Dv / Dn) was calculated.
The obtained colored resin particles had a volume average particle size (Dv) of 9.7 μm, a number average particle size (Dn) of 8.5 μm, and a particle size distribution (Dv / Dn) of 1.14.

The average circularity of the obtained colored resin particles was examined.
Into a container, 10 mL of ion exchange water is put in advance, 0.02 g of a surfactant (alkylbenzene sulfonic acid) is added as a dispersant, 0.02 g of a measurement sample (colored resin particles) is further added, and an ultrasonic disperser is added. And 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 Corporation). 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)
The average circularity of the obtained colored resin particles was 0.987.

4). Production of toner for developing electrostatic image [Example 1]
0.8 parts of silica fine particles 1 produced in Production Example 1 above as silica fine particles (A) with respect to 100 parts of colored resin particles described in the section “3. Production and evaluation of colored resin particles” above. (B) Hydrophobized number average primary particle diameter 7 nm silica fine particles (manufactured by Cabot Corp., trade name: TG820F) 0.2 parts silica fine particles (C) hydrophobized number average primary 1.5 parts of silica fine particles having a particle diameter of 50 nm (Clariant, trade name: H05TA) were added, and using a high-speed stirrer (trade name: Henschel mixer, 10 minutes) at a peripheral speed of 40 m / s. The toner of Example 1 was produced by mixing and stirring to perform an external addition process.

[Example 2]
As shown in Table 2, in Example 1, Example 1 was carried out in the same manner as Example 1 except that 0.8 part of silica fine particle 1 was changed to 0.6 part of silica fine particle 2 produced in Production Example 2 above. 2 toners were produced.

[Example 3]
As shown in Table 2, in Example 1, Example 1 was carried out in the same manner as Example 1 except that 0.8 part of silica fine particle 1 was changed to 0.8 part of silica fine particle 3 produced in Production Example 3 above. 3 toners were produced.

[ Reference Example 4 ]
As shown in Table 2, in Example 1, 0.8 parts of silica fine particles 1 were changed to 0.8 parts of silica fine particles 4 produced in Production Example 4 above, and Reference Example was performed in the same manner as Example 1. 4 toner was produced.

[ Reference Example 5 ]
As shown in Table 2, in Example 1, the silica microparticles 1 0.8 parts except that the silica particles 5 1 part prepared in Preparation Example 5, in the same manner as in Example 1 of Reference Example 5 A toner was produced.

[Comparative Example 1]
As shown in Table 2, in Example 1, 0.8 parts of silica fine particles 1 were changed to 0.8 parts of silica fine particles 6 produced in Production Example 6 above, and Comparative Example was performed in the same manner as Example 1. 1 toner was produced.

[Comparative Example 2]
As shown in Table 2, in Example 1, 0.8 parts of silica fine particles 1 were changed to 0.8 parts of silica fine particles 7 produced in Production Example 7 above, and Comparative Example was performed in the same manner as Example 1. 2 toners were produced.

[Comparative Example 3]
As shown in Table 2, in Example 1, 0.8 parts of silica fine particles 1 were changed to 0.8 parts of silica fine particles 8 produced in Production Example 8 above, and Comparative Example was performed in the same manner as Example 1. 3 toners were produced.

[Comparative Example 4]
As shown in Table 2, in Example 1, 0.8 parts of silica fine particles 1 were changed to 0.8 parts of silica fine particles 9 produced in Production Example 9 above, and Comparative Example was performed in the same manner as Example 1. 4 toner was produced.

[Comparative Example 5]
As shown in Table 2, in Example 1, 0.8 parts of silica fine particles 1 were changed to 0.8 parts of silica fine particles 10 produced in Production Example 10 above, and Comparative Example was performed in the same manner as Example 1. 5 toners were produced.

5. Evaluation of Physical Properties of Toner The toner characteristics of the electrostatic image developing toners of Examples 1 to 3, Reference Examples 4 to 5 , and Comparative Examples 1 to 5 were examined. Details are as follows.

5-1. Measurement of charge amount (under normal temperature and normal humidity (N / N) environment, high temperature and high humidity (H / H) environment) 9.95 g of carrier (product name “NZ-3” manufactured by Powder Tech Co., Ltd.) and sample (toner ) Weigh 0.05 g, put it in a glass bottle with a capacity of 100 cc, rotate for 30 minutes at 150 rpm, and then use a blow-off meter (trade name “TB-203” manufactured by Toshiba Chemical Co., Ltd.) Nitrogen gas was blown at a pressure of 4.5 kPa and sucked at a pressure of 9.5 kPa to measure the blow-off charge amount.
The measurement was performed at a temperature of 23 ° C. and a relative humidity of 50%.

5-2. Fog test under high-temperature and high-humidity (H / H) environment A commercially available non-magnetic one-component development type printer (HL-3040CN) was used for the printing durability test. After the toner cartridge of the developing device was filled with toner, it was left in a high temperature and high humidity environment (temperature: 35 ° C., humidity: 80%) for 24 hours.
After leaving, one sheet of solid white printing was performed and visually checked for fogging. Then, the whiteness on the paper surface of the white printed matter was measured using the whiteness meter (made by Nippon Denshoku).
[(Whiteness before printing)-(Whiteness of solid printed matter)] = (Fog density)
And the fog density was calculated.

5-3. Printing durability (under normal temperature and normal humidity (N / N) environment, high temperature and high humidity (H / H) environment) test For the printing durability test, a commercially available non-magnetic one-component development type printer (HL-3040CN) is used. Used, the toner cartridge of the developing device was filled with toner, and then the printing paper was set.
After standing for 24 hours in a normal temperature and normal humidity (N / N) environment (temperature: 23 ° C., humidity: 50%), continuous printing was performed up to 10,000 sheets at a 5% print density in the same environment. .
Black solid printing (printing density 100%) was performed every 500 sheets, and the printing density of the black solid image was measured using a reflective image densitometer (trade name: RD918, manufactured by Macbeth). After that, white solid printing (printing density 0%) is performed, the printer is stopped in the middle of white solid printing, and the toner in the non-image area on the developed photosensitive member is adhesive tape (manufactured by Sumitomo 3M Ltd., product) Name: Scotch mending tape 810-3-18), and then peeled off and affixed to printing paper. Next, the whiteness (B) of the printing paper on which the adhesive tape is affixed is measured with a whiteness meter (trade name: ND-1 manufactured by Nippon Denshoku Co., Ltd.). The whiteness (A) was measured and the difference in whiteness (B−A) was defined as the fog value (%). Smaller values indicate better fog and better.
The number of continuously printed sheets that can maintain an image quality with a print density of 1.3% or more and a fog value of 3% or less was examined.
The same printing durability test was also performed in a high temperature and high humidity (H / H) environment (temperature: 35 ° C., humidity: 80%).
In Table 1, “10,000 <” means that the image density of 1.3% or more and the fog value of 3% or less could be maintained even when 10,000 sheets were printed. Indicates.

5-4. Evaluation of storability 10 g of the toner was precisely weighed, sealed in a glass bottle, allowed to stand in warm water at 55 ° C. for 8 hours, then taken out of the glass bottle, and after opening, the toner was placed on a sieve having an opening of 355 μm. Next, this sieve was vibrated for 15 seconds under the condition of vibration intensity scale 4 using a powder measuring machine (trade name “Powder Tester” manufactured by Hosokawa Micron Co., Ltd.), and then the mass of toner remaining on each sieve was measured. Then, the storage stability was evaluated. A toner having a small amount of toner remaining on the sieve is evaluated as having good storage stability.

The measurement and evaluation results of the electrostatic image developing toners of Examples 1 to 3, Reference Examples 4 to 5 and Comparative Examples 1 to 5 are combined with the type and amount of silica fine particles (A). Table 2 shows.

6). Summary of Toner Evaluation Hereinafter, the toner evaluation will be examined with reference to Tables 1 and 2.
First, the toner of Comparative Example 1 is examined. From Table 1, the toner of Comparative Example 1 has the BET specific surface area of the silica fine particles (S) before the surface treatment of 90 (m ² / g), and the carbon content (mass%) of the silica fine particles (A) is the surface. The value divided by the BET specific surface area (m ² / g) of the silica fine particles (S) before treatment is 1.56 × 10 ⁻² (g / m ² ), and the nitrogen content (mass by mass) of the silica fine particles (A) %) Divided by the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment is 1.11 × 10 ⁻³ (g / m ² ) as the external additive. contains.
From Table 2, the toner of Comparative Example 1 has a charge amount value of 33.1 μC / g in a normal temperature and normal humidity (N / N) environment, and a charge amount value of 23 in a high temperature and high humidity (H / H) environment. .8μC / g, the number of fog generation in a normal temperature and normal humidity (N / N) environment exceeds 10,000, and the number of fog generation in a high temperature and high humidity (H / H) environment is 8,000. It is. Therefore, for the toner of Comparative Example 1, there is no problem with at least the charge amount.
However, the toner of Comparative Example 1 has a high fog density of 3.8 in a high-temperature and high-humidity (H / H) environment and a high storage value of 3.3.
Therefore, the value obtained by dividing the carbon content (% by mass) of the silica fine particles (A) by the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment is 3.5 × 10 ⁻² (g / m ² ), and the value obtained by dividing the nitrogen content (% by mass) of the silica fine particles (A) by the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment is 2.0 ×. It can be seen that the toner of Comparative Example 1 containing silica fine particles 6 of less than 10 ⁻³ (g / m ² ) is inferior in printing durability and storage stability.

Next, the toner of Comparative Example 2 will be examined. From Table 1, the toner of Comparative Example 2 has the BET specific surface area of the silica fine particles (S) before the surface treatment of 90 (m ² / g), and the carbon content (mass%) of the silica fine particles (A) is the surface. The value divided by the BET specific surface area (m ² / g) of the silica fine particles (S) before treatment is 1.78 × 10 ⁻² (g / m ² ), and the nitrogen content (mass by mass) of the silica fine particles (A) %) Divided by the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment is 6.67 × 10 ⁻³ (g / m ² ) of silica fine particles 7 as an external additive. contains.
Table 2 shows that the toner of Comparative Example 2 has a fog generation number exceeding 10,000 in a room temperature and normal humidity (N / N) environment. Therefore, with respect to the toner of Comparative Example 1, there is no problem in at least printing durability in a normal temperature and normal humidity (N / N) environment.
However, the toner of Comparative Example 2 has a low charge amount of 25.1 μC / g in a normal temperature and normal humidity (N / N) environment. Further, the toner of Comparative Example 2 has a low charge amount value of 9.6 μC / g in a high temperature and high humidity (H / H) environment, and a high fog density of 30.3 in the same environment. The fog generation number is as small as 7,000, and the storage stability value is as high as 2.5. In particular, the value of the charge amount under a high temperature and high humidity (H / H) environment is the lowest among the toners of Examples 1 to 3, Reference Examples 4 to 5, and Comparative Examples 1 to 5. The fog density in the environment is the highest among these toners.
Therefore, the value obtained by dividing the carbon content (% by mass) of the silica fine particles (A) by the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment is 3.5 × 10 ⁻² (g / m ² ), and the value obtained by dividing the nitrogen content (% by mass) of the silica fine particles (A) by the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment is 4.0 ×. The toner of Comparative Example 2 containing silica fine particles 7 having a value exceeding 10 ⁻³ (g / m ² ) is inferior in chargeability, printing durability and storage stability particularly in a high temperature and high humidity (H / H) environment. I understand.

Subsequently, the toner of Comparative Example 3 will be examined. From Table 1, the toner of Comparative Example 3 has the BET specific surface area of the silica fine particles (S) before the surface treatment of 130 (m ² / g), and the carbon content (mass%) of the silica fine particles (A) is the surface. The value divided by the BET specific surface area (m ² / g) of the silica fine particles (S) before treatment is 4.00 × 10 ⁻² (g / m ² ), and the nitrogen content (mass by mass) of the silica fine particles (A) %) Is divided by the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment, and contains silica fine particles 8 having a value of 0.00 as an external additive.
From Table 2, the toner of Comparative Example 3 has a low charge amount value of 18.0 μC / g in a normal temperature and normal humidity (N / N) environment, and the number of fog occurrences in that environment is as low as 8,000. Further, the toner of Comparative Example 3 has a low charge amount value of 14.2 μC / g in a high temperature and high humidity (H / H) environment and a high fog density of 5.2 in the same environment. The number of fog generation is as small as 7,000, and the storage stability is as high as 2.8.
Therefore, the value obtained by dividing the carbon content (% by mass) of the silica fine particles (A) by the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment is 3.5 × 10 ^{−2 to} 5. Although it is in the range of 5 × 10 ⁻² (g / m ² ), the nitrogen content (mass%) of the silica fine particles (A) is changed to the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment. ), The toner of Comparative Example 3 containing silica fine particles 8 having a value less than 2.0 × 10 ⁻³ (g / m ² ) may be generally inferior in chargeability, printing durability and storage stability. I understand.

Next, the toner of Comparative Example 4 will be examined. From Table 1, the toner of Comparative Example 4 has the BET specific surface area of the silica fine particles (S) before the surface treatment of 130 (m ² / g), and the carbon content (mass%) of the silica fine particles (A) is the surface. The value divided by the BET specific surface area (m ² / g) of the silica fine particles (S) before treatment is 5.62 × 10 ⁻² (g / m ² ), and the nitrogen content (mass by mass) of the silica fine particles (A) %) Divided by the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment is 4.08 × 10 ⁻³ (g / m ² ) of silica fine particles 9 as an external additive. contains.
From Table 2, the toner of Comparative Example 4 has a storage stability value of 1.0. Therefore, for the toner of Comparative Example 4, there is at least no problem in storage stability.
However, the toner of Comparative Example 4 has a low charge amount value of 16.3 μC / g in a normal temperature and normal humidity (N / N) environment, and the number of fog occurrences in that environment is as low as 7,000. In particular, the value of the charge amount in a normal temperature and normal humidity (N / N) environment is the lowest among the toners of Examples 1 to 3, Reference Examples 4 to 5, and Comparative Examples 1 to 5. The number of fog occurrences under the environment is the smallest among these toners.
Further, the toner of Comparative Example 4 has a low charge amount value of 12.3 μC / g in a high temperature and high humidity (H / H) environment, and a high fog density of 11.2 in the same environment. The number of fogging is as small as 5,000. In particular, the number of fog occurrences in a high-temperature and high-humidity (H / H) environment is the smallest among the toners of Examples 1 to 3, Reference Examples 4 to 5, and Comparative Examples 1 to 5.
Therefore, the value obtained by dividing the carbon content (% by mass) of the silica fine particles (A) by the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment is 5.5 × 10 ⁻² (g / m ² ), and the value obtained by dividing the nitrogen content (% by mass) of the silica fine particles (A) by the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment is 4. The toner of Comparative Example 4 containing silica fine particles 9 having a value exceeding 0 × 10 ⁻³ (g / m ² ) is particularly excellent in chargeability and printing durability in a normal temperature and normal humidity (N / N) environment, as well as high temperature and high temperature. It can be seen that the printing durability in a wet (H / H) environment is inferior.

Next, the toner of Comparative Example 5 will be examined. From Table 1, the toner of Comparative Example 5 has the BET specific surface area of the silica fine particles (S) before the surface treatment of 300 (m ² / g), and the carbon content (mass%) of the silica fine particles (A) is the surface. The value divided by the BET specific surface area (m ² / g) of the silica fine particles (S) before treatment is 4.00 × 10 ⁻² (g / m ² ), and the nitrogen content (mass by mass) of the silica fine particles (A) %) Divided by the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment, the silica fine particles 10 having 3.33 × 10 ⁻³ (g / m ² ) as an external additive. contains.
From Table 2, the toner of Comparative Example 5 has a low charge amount value of 27.3 μC / g in a normal temperature and normal humidity (N / N) environment, and the number of fog occurrences in that environment is as low as 8,000. Further, the toner of Comparative Example 5 has a low charge amount value of 15.9 μC / g in a high-temperature and high-humidity (H / H) environment, and a high fog density of 8.1 in the same environment. The fog generation number is as small as 5,000 and the storage stability is as high as 7.3. In particular, the number of fog occurrences in a high-temperature and high-humidity (H / H) environment is the smallest among the toners of Examples 1 to 3, Reference Examples 4 to 5, and Comparative Examples 1 to 5, and The shelf life value is the highest among these toners.
Therefore, the value obtained by dividing the carbon content (% by mass) of the silica fine particles (A) by the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment is 3.5 × 10 ^{−2 to} 5. Within the range of 5 × 10 ⁻² (g / m ² ), the nitrogen content (mass%) of the silica fine particles (A) is the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment. The value divided by 2.0 is in the range of 2.0 × 10 ^{−3 to} 4.0 × 10 ⁻³ (g / m ² ), but the BET specific surface area of the silica fine particles (S) before the surface treatment is 200 (m The toner of Comparative Example 5 containing silica fine particles 10 exceeding ² / g) is generally inferior in charging property, printing durability and storage stability, particularly printing durability in a high temperature and high humidity (H / H) environment, and It turns out that it is inferior in preservability.

On the other hand, the toners of Examples 1 to 3 and Reference Examples 4 to 5 have a BET specific surface area of the silica fine particles (S) before the surface treatment of 70 to 200 (m ² / g) according to Table 1. The value obtained by dividing the carbon content (% by mass) of the silica fine particles (A) by the BET specific surface area (m ² / g) of the silica fine particles (S) before the surface treatment is 3.5 × 10 ⁻² to It is in the range of 5.5 × 10 ⁻² (g / m ² ), and the BET specific surface area (m ² / m ² ) of the silica fine particles (S) before the surface treatment is determined based on the nitrogen content (mass%) of the silica fine particles (A). Silica fine particles having a value divided by g) in the range of 2.0 × 10 ^{−3 to} 4.0 × 10 ⁻³ (g / m ² ) are contained as an external additive.
From Table 2, the toners of Examples 1 to 3 and Reference Examples 4 to 5 have a charge amount value of 28.8 μC / g or more in a normal temperature and normal humidity (N / N) environment. The number of fog occurrences in the same environment exceeds 10,000. The toners of Examples 1 to 3 and Reference Examples 4 to 5 all have a high charge value of 18.4 μC / g or more in a high temperature and high humidity (H / H) environment. The fog density in the same environment is as low as 1.2 or less, the fog generation number in the same environment is 8,000 or more, and the storage stability value is as low as 2.4 or less.
Therefore, both the BET specific surface area conditions of the silica fine particles (S) before the surface treatment and the above-described formulas (1) and (2) are satisfied, and 0.4 to 2 with respect to 100 parts by mass of the colored resin particles. The toner of the present invention containing silica fine particles (A) having an addition amount in the range of 0.0 part by mass exhibits stable charging over time regardless of temperature conditions and humidity conditions, and allows continuous printing of a large number of sheets. It can be seen that the toner is an electrostatic charge image developing toner that hardly deteriorates in image quality due to fog or the like and has excellent storability.

Claims (5)

In the toner for developing an electrostatic image containing a colored resin particle containing a binder resin and a colorant and an external additive,
The external additive contains silica fine particles (A),
The silica fine particles (A) are obtained by hydrophobizing silica fine particles (S) having a BET specific surface area of 70 to 200 (m ² / g) with a silicon compound , and the following formulas (1) and (2) And 0.4 to 2.0 parts by mass of the colored resin particles are added to 100 parts by mass of the colored resin particles.
  The electrostatic charge image developing toner according to claim 1, wherein the adsorbed moisture amount of the silica fine particles (A) is 0.1 to 0.7 mass%. The external additive further contains silica fine particles (B) having a number average primary particle size of 5 to 14 nm,
The electrostatic charge image developing toner according to claim 1, wherein the silica fine particles (B) are added in an amount of 0.05 to 3 parts by mass with respect to 100 parts by mass of the colored resin particles. The external additive further contains silica fine particles (C) having a number average primary particle size of 35 to 200 nm,
The electrostatic charge image according to any one of claims 1 to 3, wherein 0.05 to 3 parts by mass of the silica fine particles (C) are added to 100 parts by mass of the colored resin particles. Development toner.   The colored resin particles contain a positively chargeable charge control agent, have a volume average particle diameter of 4 to 12 μm, and an average circularity of 0.96 or more. The toner for developing an electrostatic charge image according to any one of the above.