JP2012177885A - Positively chargeable toner for electrostatic latent image development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positively chargeable toner for electrostatic latent image development, the toner which has excellent rising property upon charging and excellent developability, which hardly induces problems such as toner scattering even when printing with a low printing rate is carried out for a long time and the toner is stirred for a long time in a developing device, and which is excellent in durability.SOLUTION: The positively chargeable toner for electrostatic latent image development includes charge controlling domains comprising a mixture of a charge controlling agent including a nitrogen atom and a charge controlling resin in a binder resin. The binder resin comprises a polyester resin. The charge controlling resin comprises a quaternary ammonium salt functional group-containing resin, which is a copolymer of an addition polymerizable monomer having a quaternary ammonium salt functional group and a styrene and/or acrylic monomer. The charge controlling domains are present on the toner surface.

Description

  The present invention relates to a positively chargeable electrostatic latent image developing toner.

  In general, in an image forming method such as electrophotography or electrostatic recording, the surface of an electrostatic latent image carrier (photoconductor) is charged by corona discharge or the like, and then exposed by a laser or the like to form an electrostatic latent image. The electrostatic latent image is developed with toner to form a toner image, and the toner image is transferred to a recording medium to obtain a high quality image. Usually, toner used for forming a toner image is mixed with a binder resin such as a thermoplastic resin, a colorant, a charge control agent, a release agent and the like, kneaded, pulverized, and classified to have an average particle diameter of 5 to 15 μm. Toner particles are used. For the purpose of imparting fluidity to the toner, controlling the charge amount of the toner, and improving the cleaning property of the toner remaining on the photoreceptor without being transferred, inorganic fine particles such as silica and titanium oxide are used. Powder and inorganic metal fine powder are externally added to the toner.

  In recent years, in an image forming apparatus using an electrophotographic method, an electrostatic recording method, or the like, in addition to an improvement in image quality, a longer life and a higher speed are required. In order to meet such demands on the image forming apparatus, it is important to have a good toner charge start-up property that can be stably charged to a desired charge amount in a short time. When the toner has insufficient charge-up properties, development is performed with a poorly charged toner, so the two-component developer has problems such as an increase in image density, image fog, and toner scattering in the image forming apparatus. One-component developer tends to cause problems such as insufficient image density and image unevenness.

  In order to solve the problem of charge rising property and charge stability related to toner, for example, an emulsion composed of an aqueous medium containing an organic solvent and a positively chargeable charge control resin, and a binder resin that is a polyester resin A toner is proposed in which a suspension of toner base particles containing a colorant is mixed and a positively chargeable charge control resin is adhered to the surface of the toner base particles (Patent Document 1).

JP 2008-186002 A

  The toner described in Patent Document 1 is excellent in initial chargeability and excellent in initial developability because the toner can be charged to a desired charge amount in a short time. However, in the toner described in Patent Document 1, since the positively chargeable charge control resin is simply attached to the toner base particles, printing with a low printing rate is performed over a long period of time. When the toner is stirred for a long time, the charge control resin tends to fall off the surface. In such a case, since the toner base particles made of polyester resin are negatively charged, the toner base particles are likely to repel negatively charged carriers and the like, and the inside of the image forming apparatus is likely to be contaminated by toner scattering.

  The present invention has been made in view of such circumstances, and has excellent charging startability, excellent developability, low-printing printing for a long time, and the toner is stirred for a long time in the developing device. However, it is an object of the present invention to provide a toner for developing a positively chargeable electrostatic latent image that hardly causes problems such as toner scattering and has excellent durability.

  The present inventors have a charge control domain composed of a mixture of a charge control agent containing a nitrogen atom and a charge control resin in the binder resin, the binder resin is a polyester resin, and the charge control resin is 4 A quaternary ammonium salt functional group-containing resin that is a copolymer of a monomer having an addition of a quaternary ammonium salt functional group and a styrene and / or acrylic monomer, and the charge control domain is present on the toner surface. The present inventors have found that the above problems can be solved by a toner for developing an electrostatic latent electrostatic image, and have completed the present invention. More specifically, the present invention provides the following.

  (1) The binder resin has a charge control domain composed of a mixture of a charge control agent containing a nitrogen atom and a charge control resin, the binder resin is a polyester resin, and the charge control resin is a quaternary ammonium. A positively chargeable composition comprising a quaternary ammonium salt functional group-containing resin which is a copolymer of a monomer having a salt functional group and capable of addition polymerization and a styrene and / or acrylic monomer, wherein the charge control domain is present on the toner surface Toner for electrostatic latent image development.

  (2) N1 to N29 (Nn is a dispersion diameter of (0.01) when the dispersion diameters of 50 or more charge control domains are measured using an image with a magnification of 10,000 times acquired by a scanning electron microscope. Xn) The charge control in which the dispersion diameter is measured as the sum of the number of the charge control domains equal to or greater than μm and less than (0.01 × (n + 1)) μm, where n is a positive integer equal to or greater than 1. The positively charged electrostatic latent image according to (1), wherein the number% of the total number of domains is 98% by number or more, and the ratio of the sum of the areas of the charge control domains to the area of the toner cross section is 1 to 10 area%. Toner for image development.

  (3) The amount of the charge control agent containing nitrogen atoms contained in the toner is 1 to 10% by mass with respect to the total mass of the charge control agent containing nitrogen atoms and the charge control resin contained in the toner. The positively chargeable electrostatic latent image developing toner according to (1) or (2).

  (4) The positively chargeable electrostatic latent image developing toner according to any one of (1) to (3), wherein the charge control agent containing a nitrogen atom is a quaternary ammonium salt.

  (5) In the quaternary ammonium salt functional group-containing resin, the total amount of repeating units derived from the addition-polymerizable monomer having the quaternary ammonium salt functional group constitutes the quaternary ammonium salt functional group-containing resin. The positively chargeable electrostatic latent image developing toner according to any one of (1) to (4), wherein the amount is 0.1 to 20 mol% with respect to the repeating unit.

  According to the present invention, the charging start-up property is excellent, the developing property is excellent, the problem such as the scattering of toner hardly occurs even when the developing device is stirred for a long time in the developing device, and the durability is high. A toner for developing a chargeable electrostatic latent image can be provided.

FIG. 3 is an electron micrograph of the toner of Example 1 in which a charge control domain drop mark is formed.

  Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present invention. In addition, although description may be abbreviate | omitted suitably about the location where description overlaps, the summary of invention is not limited.

  The positively chargeable electrostatic latent image developing toner of the present invention (hereinafter also simply referred to as toner) is an addition having a charge control agent containing a nitrogen atom and a quaternary ammonium salt functional group to a polyester resin as a binder resin. A charge control domain is formed by dispersing a mixture of a polymerizable monomer and a charge control resin containing a quaternary ammonium salt functional group-containing resin which is a copolymer of styrene and / or an acrylic monomer, and a toner A charge control domain is present on the surface of the substrate. The toner of the present invention may contain a colorant, a release agent and the like as necessary in the binder resin. The toner of the present invention may have a surface treated with an external additive as desired. Furthermore, the toner of the present invention can be mixed with a desired carrier and used as a two-component developer.

  Hereinafter, the essential or optional components constituting the toner of the present invention, which are a binder resin, a colorant, a release agent, a charge control domain, an external additive, and the toner of the present invention as a two-component developer. A carrier used in the case of use and a method for producing a positively chargeable electrostatic latent image developing toner will be described in order.

[Binder resin]
The positively chargeable electrostatic latent image developing toner of the present invention uses a polyester resin as a binder resin. As the polyester resin, those obtained by condensation polymerization or co-condensation polymerization of an alcohol component and a carboxylic acid component can be used. The components used when synthesizing the polyester resin include the following alcohol components and carboxylic acid components.

  A divalent or trivalent or higher alcohol can be used as the alcohol component. Specific examples of the divalent or trivalent or higher alcohol component include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1 Diols such as 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol; bisphenol A, Bisphenols such as hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A; sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, Entaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,4- Examples include trivalent or higher alcohols such as butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5-trihydroxymethylbenzene.

  As the carboxylic acid component, a divalent or trivalent or higher carboxylic acid can be used. Specific examples of the divalent or trivalent or higher carboxylic acid component include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, Sebacic acid, azelaic acid, malonic acid, or n-butyl succinic acid, n-butenyl succinic acid, isobutyl succinic acid, isobutenyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid Divalent carboxylic acids such as acids, isododecyl succinic acid, isododecenyl succinic acid and the like or alkyl or alkenyl succinic acid; 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5-benzenetricarboxylic acid Acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphtha Tricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid , Tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, emporic trimer acid, and other trivalent or higher carboxylic acids. These divalent or trivalent or higher carboxylic acid components may be used as ester-forming derivatives such as acid halides, acid anhydrides, and lower alkyl esters. Here, “lower alkyl” means an alkyl group having 1 to 6 carbon atoms.

  The softening point of the polyester resin is preferably 80 to 150 ° C, more preferably 90 to 140 ° C.

  As the binder resin, other thermoplastic resins of the polyester resin compatible with the polyester resin can be used together with the polyester resin as long as the object of the present invention is not impaired.

  The usage-amount of the other thermoplastic resin of a polyester resin is not specifically limited in the range which does not inhibit the objective of this invention. The amount of the other thermoplastic resin used in the polyester resin is typically 50 parts by mass or less, preferably 30 parts by mass with respect to 100 parts by mass of the total amount of the polyester resin and the other thermoplastic resin of the polyester resin. The following is more preferable, and 10 parts by mass or less is particularly preferable.

  Further, the binder resin does not contain a charge control agent. Here, not including the charge control agent is not limited to a mode in which the charge control agent is not completely included, and includes a case where a small amount of the charge control agent is inevitably mixed in the toner manufacturing process.

[Colorant]
The positively chargeable electrostatic latent image developing toner of the present invention may contain a colorant in the binder resin. As the colorant that can be blended in the binder resin, known pigments and dyes can be used according to the color of the toner. Specific examples of suitable colorants to be added to the toner include black pigments such as carbon black, acetylene black, lamp black, and aniline black; yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow , Yellow pigments such as Navels Yellow, Naphthol Yellow S, Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow G, Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake; Red Yellow Yellow Lead, Molybdenum Orange, Permanent Orange Orange pigments such as GTR, Pyrazolone Orange, Vulcan Orange, Indanthrene Brilliant Orange GK; Bengala, Cadmium Red, Lead Tan, Mercury Cadmium, Permanent Red 4R, Lithium Red pigments such as Lured, Pyrazolone Red, Watching Red Calcium Salt, Lake Red D, Brilliant Carmine 6B, Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B; Purple such as Manganese Purple, Fast Violet B, Methyl Violet Lake Pigment: Blue pigment such as bitumen, cobalt blue, alkali blue lake, Victoria blue partially chlorinated, First Sky Blue, Indanthrene Blue BC; Chrome Green, Chrome Oxide, Pigment Green B, Malachite Green Lake, Final Yellow Green G, etc. Green pigments; white pigments such as zinc white, titanium oxide, antimony white, zinc sulfide; barite powder, barium carbonate, clay, silica, white carbon, talc, alumina white, etc. It includes the quality pigments. These colorants may be used in combination of two or more for the purpose of adjusting the toner to a desired hue.

  The amount of the colorant used is not particularly limited as long as the object of the present invention is not impaired. Specifically, 1-10 mass parts is preferable with respect to 100 mass parts of binder resin, and 3-7 mass parts is more preferable.

〔Release agent〕
The positively chargeable electrostatic latent image developing toner of the present invention may contain a release agent in the binder resin for the purpose of improving the toner fixability and offset resistance. The type of release agent that can be blended into the binder resin is not particularly limited as long as the object of the present invention is not impaired. The mold release agent is preferably a wax, and examples of the wax include polyethylene wax, polypropylene wax, fluororesin-based wax, Fischer-Tropsch wax, paraffin wax, ester wax, montan wax, rice wax and the like. These waxes can be used in combination of two or more. By adding such a release agent to the toner, the occurrence of offset and image smearing (stain around the image when the image is rubbed) can be more efficiently suppressed.

  The amount of the release agent used is not particularly limited as long as the object of the present invention is not impaired. A specific amount of the release agent used is preferably 1 to 5 parts by mass when the total amount of toner is 100 parts by mass. If the amount of release agent used is too small, the desired effect may not be obtained with respect to the suppression of the occurrence of offset and image smearing. If the amount of release agent used is excessive, fusion between toners may occur. Depending on the case, the storage stability may decrease.

[Charge control domain]
The positively chargeable electrostatic latent image developing toner of the present invention comprises a charge control agent containing a nitrogen atom and a charge control resin in a binder resin in which a colorant, a release agent, a charge control agent and the like are mixed as desired. And a positively chargeable charge control domain made of a mixture of a charge control agent containing a nitrogen atom and a charge control resin is formed, and the charge control domain is present on the toner surface.

  The charge control resin used for forming the charge control domain is a quaternary ammonium salt functional group-containing resin that is a copolymer of an addition-polymerizable monomer having a quaternary ammonium salt functional group and styrene and / or an acrylic monomer. Use. The quaternary ammonium salt functional group-containing resin can be used as it is, or a quaternary ammonium salt functional group-containing resin mixed with a polystyrene resin as necessary.

  The quaternary ammonium salt functional group-containing resin uses a copolymer of an addition-polymerizable monomer having a quaternary ammonium salt functional group and a styrene and / or acrylic monomer. Since such a quaternary ammonium salt functional group-containing resin is incompatible with the polyester resin as the binder resin, a charge control domain dispersed in a desired state is easily formed on the surface of the toner.

  The addition-polymerizable monomer having a quaternary ammonium salt functional group is derived from a dialkylaminoalkyl (meth) acrylate, dialkyl (meth) acrylamide, or dialkylaminoalkyl (meth) acrylamide through a quaternization step. Monomers are used. Specific examples of the dialkylaminoalkyl (meth) acrylate include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dipropylaminoethyl (meth) acrylate, dibutylaminoethyl (meth) acrylate and the like. Specific examples of dialkyl (meth) acrylamide include dimethylmethacrylamide, and specific examples of dialkylaminoalkyl (meth) acrylamide include dimethylaminopropylmethacrylamide. Specific examples of the reagent used for the quaternization of the tertiary amino group include alkyl halides having 1 to 6 carbon atoms such as methyl chloride, methyl bromide and ethyl chloride; 1 carbon atom such as dimethyl sulfate and diethyl sulfate. Sulfuric acid ester which is an alkyl ester of -6; Aralkyl halide having 7 to 10 carbon atoms such as benzyl chloride. Two or more kinds of addition-polymerizable monomers having a quaternary ammonium salt functional group can be used.

  The amount of the repeating unit derived from the addition-polymerizable monomer having a quaternary ammonium salt functional group in the quaternary ammonium salt functional group-containing resin is not particularly limited as long as the object of the present invention is not impaired. A suitable amount of the repeating unit derived from the addition-polymerizable monomer having a quaternary ammonium salt functional group is specifically 0.1% with respect to all the repeating units constituting the quaternary ammonium salt functional group-containing resin. -20 mol% is preferable and 0.5-10 mol% is more preferable. When the amount of the repeating unit derived from the addition-polymerizable monomer having a quaternary ammonium salt functional group is too small, an increase in image density and image defects such as fogging are likely to occur. When the amount of the repeating unit derived from the addition-polymerizable monomer having a quaternary ammonium salt functional group is excessive, image defects such as a decrease in charge amount, an increase in image density, and fogging are likely to occur under high temperature and high humidity. Become.

  Various acrylic acid derivatives or methacrylic acid derivatives can be used as the acrylic monomer used in the production of the quaternary ammonium salt functional group-containing resin. Specific examples of suitable acrylic monomers are methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, α-chloro. (Meth) acrylic acid esters such as methyl acrylate, methyl methacrylate, ethyl methacrylate and butyl methacrylate; and other acrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide. These acrylic monomers can be used in combination of two or more.

  The quaternary ammonium salt functional group-containing resin is an addition-polymerizable monomer having a quaternary ammonium salt functional group, a styrene and / or acrylic monomer, and other additions of these monomers as long as the object of the present invention is not impaired. It may be a resin copolymerized with a polymerizable copolymerizable monomer. Specific examples of the copolymerization monomer include p-chlorostyrene; vinyl naphthalene; ethylene unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl halides such as vinyl chloride, vinyl bromide, and vinyl fluoride; vinyl acetate. Vinyl esters such as vinyl propionate, vinyl benzoate and vinyl butyrate; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole N-vinyl compounds such as N-vinylcarbazole, N-vinylindole, and N-vinylpyrrolidene. These copolymerizable monomers can be copolymerized with a styrene monomer in combination of two or more.

  In the quaternary ammonium salt functional group-containing resin, the amount of repeating units derived from addition copolymerizable monomers having a quaternary ammonium salt functional group, styrene, and other copolymerization monomers of acrylic monomers hindered the purpose of the present invention. The range is not particularly limited. Typically, it is preferably 30 mol% or less, more preferably 10 mol% or less, based on all repeating units constituting the quaternary ammonium salt functional group-containing resin.

  The quaternary ammonium salt functional group-containing resin can be prepared by copolymerizing the above-described monomers in combination at a desired ratio. The polymerization method for producing the quaternary ammonium salt functional group-containing resin is not particularly limited, and any method such as solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization and the like can be selected.

  As the charge control resin, a quaternary ammonium salt functional group-containing resin can be used alone, but a quaternary ammonium salt functional group-containing resin and a polystyrene resin can also be mixed and used. When mixing and using a quaternary ammonium salt functional group-containing resin and a polystyrene resin, the charge control resin is particularly dispersed in the binder resin when the binder resin and the charge control resin are melt-kneaded during toner production. It is easy to manufacture the toner in which the charge control domain is formed in a desired state.

  When the quaternary ammonium salt functional group-containing resin and the polystyrene resin are mixed and used, the mixing method is not particularly limited as long as both are uniformly mixed. Specific examples of the method of mixing the quaternary ammonium salt functional group-containing resin and the polystyrene resin include melt-kneading using a single screw extruder or a twin screw extruder or the quaternary ammonium salt functional group containing resin and the polystyrene resin. Can be dissolved in an organic solvent, and then the organic solvent is removed.

  The polystyrene resin mixed with the quaternary ammonium salt functional group-containing resin may be a polymer of styrene alone or may be a copolymer of styrene and another copolymerizable monomer of styrene. Specific examples of copolymerizable monomers that can be used with styrene include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, (Meth) acrylic esters such as methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate; other acrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide; p-chlorostyrene; vinyl Naphthalene; Ethylene unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; Vinyl halides such as vinyl chloride, vinyl bromide, and vinyl fluoride; Vinyl such as vinyl acetate, vinyl propionate, vinyl benzoate, and vinyl butyrate Vinyl esters such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl N-vinyl compounds such as pyrrolidene. These copolymerizable monomers can be copolymerized with a styrene monomer in combination of two or more.

  The amount of repeating units derived from styrene in the polystyrene resin is preferably 70 mol% or more, more preferably 90 mol% or more, based on the total amount of repeating units constituting the polystyrene resin.

  When the quaternary ammonium salt functional group-containing resin and the polystyrene resin are used in combination, the amount of the polystyrene resin used is not particularly limited as long as the object of the present invention is not impaired. Typically, the amount of the polystyrene-based resin used is preferably 20 to 200 parts by mass and particularly preferably 40 to 120 parts by mass or less with respect to 100 parts by mass of the quaternary ammonium salt functional group-containing resin.

  The type of the charge control agent containing a nitrogen atom used for forming the charge control domain is not particularly limited as long as the object of the present invention is not impaired, and the charge control agent containing a nitrogen atom conventionally used in a toner is used. Can be selected as appropriate. Specific examples of the charge control agent containing a nitrogen atom include pyridazine, pyrimidine, pyrazine, orthooxazine, metaoxazine, paraoxazine, orthothiazine, metathiazine, parathiazine, 1,2,3-triazine, 1,2,4-triazine. 1,3,5-triazine, 1,2,4-oxadiazine, 1,3,4-oxadiazine, 1,2,6-oxadiazine, 1,3,4-thiadiazine, 1,3,5-thiadiazine, 1 , 2,3,4-tetrazine, 1,2,4,5-tetrazine, 1,2,3,5-tetrazine, 1,2,4,6-oxatriazine, 1,3,4,5-oxatriazine , Azine compounds such as phthalazine, quinazoline, quinoxaline; azine fast red FC, azine fast red 12BK, azine violet BO Direct dyes composed of azine compounds such as azine brown 3G, azine light brown GR, azine dark green BH / C, azine deep black EW, and azine black 3RL; nigrosine compounds such as nigrosine, nigrosine salts, nigrosine derivatives; Acid dyes composed of nigrosine compounds such as nigrosine BK, nigrosine NB, and nigrosine Z; metal salts of naphthenic acid or higher fatty acids; alkoxylated amines; alkylamides; quaternary ammonium salts such as benzylmethylhexyldecylammonium and decyltrimethylammonium chloride Can be mentioned. Among these charge control agents, a quaternary ammonium salt is more preferable because it is excellent in affinity with a quaternary ammonium salt functional group-containing resin and easily obtains a toner having excellent durability. These charge control agents containing nitrogen atoms can be used in combination of two or more.

  The method for forming the charge control domain is not particularly limited. For example, the charge control domain is formed by melting and kneading a mixture of a charge control resin and a charge control agent, which are uniformly mixed in advance, with a binder resin. The method of uniformly mixing the charge control resin and the charge control agent is not particularly limited, and after melting and kneading or dissolving the charge control agent resin and the charge control agent in a solvent such as toluene or xylene, the solvent is added. The method of removing etc. are mentioned.

  1-10 mass% is preferable with respect to the sum total of the mass of a charge control agent and charge control resin, and, as for the usage-amount of a charge control agent, 3-8 mass% is more preferable. If the amount of the charge control agent used is too small, it may be difficult to obtain the desired chargeability, and if the amount of charge control agent used is excessive, the durability of the toner may be impaired.

  The usage-amount of the mixture of charge control resin and a charge control agent is not specifically limited in the range which does not inhibit the objective of this invention. The amount of the mixture of the charge control resin and the charge control agent is typically 1 to 10% in the area ratio of the charge control domain, which is a ratio of the sum of the area of the charge control domain in the toner cross section to the area of the toner cross section. The amount which becomes is preferable, and the amount which becomes 1.5 to 5% is more preferable. When the area ratio of the charge control domain is excessively small, it is difficult to charge the toner to a desired charge amount. When the area ratio of the charge control domain is excessively large, the toner is easily charged excessively and image defects are likely to occur.

  Further, the dispersion diameter of the charge control domain dispersed in the binder resin (hereinafter also referred to as domain diameter) is not particularly limited as long as the object of the present invention is not impaired. The number of charge control domains having a domain diameter of 0.01 μm or more and less than 0.3 μm with respect to the number of domains of the charge control resin having a domain diameter of 0.01 μm or more, measured by the method described later (hereinafter referred to as “%”). , Also referred to as a microdomain ratio) is preferably formed in the binder resin so that it is 98% by number or more. Furthermore, the dispersion diameter of the charge control domain is preferably 0.01 to 0.3 μm at the dispersion number of 99% by number from the smallest. In this manner, a toner having excellent developability and durability can be obtained by forming the charge control domain in the binder resin.

  Number of charge control domains having a domain diameter of 0.01 μm or more and less than 0.3 μm with respect to the number of charge control domains having a domain diameter of 0.01 μm or more (fine domain ratio), and the dispersion diameter of the charge control domains dispersed in the binder resin The area ratio is a melt-kneaded product of a binder resin obtained during toner production and a mixture of a charge control agent containing nitrogen atoms and a charge control resin, or a toner embedded in an ultraviolet curable resin or the like. It can be measured using a sample. Specifically, the dispersion diameter and area ratio of the charge control domain can be measured according to the following method. First, after polishing the cross section of the sample and finishing it to a mirror surface, the sample was heated at 58 ° C. for 12 hours, and then the sample was immersed in an ethanol aqueous solution (ethanol: water = 80: 20 (volume ratio)) to obtain a super A sample from which the charge control domain has dropped can be prepared by sonicating for 5 minutes with a sonic cleaning device (UT-105S (manufactured by Sharp Corporation)). A cross-section of the melt-kneaded product or toner on the surface of the obtained sample was photographed with a scanning electron microscope, and a secondary electrophotographic image (10,000 magnifications) of the dropping traces of the charge control domain dispersed in the binder resin was obtained. The obtained image is binarized by image analysis software (WinROOF (manufactured by Mitani Corporation)), and the charge control domain has a diameter of a drop mark and a charge control domain in the cross section of the melt-kneaded product or toner. The area ratio can be measured. Note that the measurement of the microdomain ratio, the domain diameter, and the area ratio of the charge control domain is performed on a charge control domain having a domain diameter of 0.01 μm or more. This is because it is difficult to observe a domain having a domain diameter of less than 0.01 μm in an electron microscope image with a magnification of 10,000 times.

  According to the above method, 50 or more, preferably 100 to 1000 domain diameters are measured, and N1 to N29 (Nn is a dispersion diameter of (0.01 × n) μm or more (0.01 × (n + 1)) μm. Less than the number of the charge control domains, and n is a positive integer of 1 or more), and the number% of the total number of the charge control domains whose dispersion diameter is measured is calculated to be 0.01 μm or more. The number% of charge control domains having a dispersion diameter of 0.01 μm or more and less than 0.3 μm with respect to the number of charge control domains can be obtained.

  Further, the minimum value of n is calculated such that the value of the number% of the sum of N1 to Nn with respect to the total number of the charge control domains whose dispersion diameters are measured becomes 99 number% when the first decimal place is rounded off, Let (0.01 × n) μm be the domain diameter (μm) of 99% by number from the smaller charge control domain dispersed in the binder resin.

(External additive)
The positively chargeable electrostatic latent image developing toner of the present invention forms a charge control domain in a binder resin and is adjusted to a desired particle size by pulverization and classification, and then the fluidity and storage stability of the toner. An external additive may be adhered to the surface for the purpose of improving the cleaning property.

  The type of external additive is not particularly limited as long as it does not impair the object of the present invention, and can be appropriately selected from external additives conventionally used for toners. Specific examples of suitable external additives include silica and metal oxides such as alumina, titanium oxide, magnesium oxide, zinc oxide, strontium titanate, and barium titanate. These external additives can be used in combination of two or more.

  The particle diameter of the external additive is not particularly limited as long as the object of the present invention is not impaired, and typically 0.01 to 1.0 μm is preferable.

  The volume specific resistance value of the external additive can be adjusted by forming a coating layer made of tin oxide and antimony oxide on the surface of the external additive and changing the thickness of the coating layer and the ratio of tin oxide to antimony oxide. .

  The amount of the external additive used relative to the toner base particles is not particularly limited as long as the object of the present invention is not impaired. Typically, the amount of the external additive used is preferably 0.1 to 10 parts by mass, more preferably 0.2 to 5 parts by mass with respect to 100 parts by mass of the toner base particles. When the external additive is used in such an amount, it is easy to obtain a toner excellent in fluidity, storage stability, and cleaning properties.

  As the external additive, one whose surface is treated with a hydrophobizing agent can be used. In the case of using a hydrophobized external additive, it is easy to suppress a decrease in charge amount under high temperature and high humidity, and it is easy to obtain a toner having excellent fluidity. As the hydrophobizing agent, for example, an aminosilane coupling agent can be used. Specific examples of the aminosilane coupling agent include γ-aminopropyltriethoxysilane, γ-aminopropylmethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, γ- (2-aminoethyl). -Γ-aminopropylmethyldimethoxysilane, γ-anilinopropyltrimethoxysilane and the like. In order to supplement the hydrophobizing effect, an aminosilane coupling agent and a hydrophobizing agent other than the aminosilane coupling agent can be used in combination. As the hydrophobizing agent other than the aminosilane coupling agent, hexamethyldisilazane is preferably used because of its excellent hydrophobizing effect and toner fluidity improving effect.

  Silicone oil can also be used as a hydrophobizing agent for external additives. The type of silicone oil is not particularly limited as long as a desired hydrophobizing effect is obtained, and various silicone oils conventionally used as a hydrophobizing agent can be used. As the silicone oil, those having a linear siloxane structure are preferable, and any of non-reactive silicone oil and reactive silicone oil can be used. Specific examples of silicone oils include dimethyl silicone oil, phenylmethyl silicone oil, chlorophenyl silicone oil, alkyl silicone oil, chlorosilicone oil, polyoxyalkylene modified silicone oil, fatty acid ester modified silicone oil, methyl hydrogen silicone oil, silanol group-containing Examples include silicone oil, alkoxy group-containing silicone oil, acetoxy group-containing silicone oil, amino-modified silicone oil, carboxylic acid-modified silicone oil, alcohol-modified silicone oil, and the like.

  As a method of hydrophobizing the external additive, a method of dropping or spraying a hydrophobizing agent such as aminosilane or silicone oil while stirring the external additive at a high speed, or an organic solvent of the hydrophobizing agent being stirred. The method of adding an external additive in a solvent solution is mentioned. The external additive subjected to the hydrophobization treatment is obtained by heating after the hydrophobization treatment. When the hydrophobizing agent is dropped or sprayed, the hydrophobizing agent can be used as it is or diluted with an organic solvent or the like.

[Carrier]
The positively chargeable electrostatic latent image developing toner of the present invention can be mixed with a desired carrier and used as a two-component developer. When preparing a two-component developer, it is preferable to use a magnetic carrier.

  A suitable carrier when the toner is a two-component developer includes a carrier core material coated with a resin. Specific examples of carrier core materials include particles of iron, oxidized iron, reduced iron, magnetite, copper, silicon steel, ferrite, nickel, cobalt, etc., and particles of alloys of these materials with manganese, zinc, aluminum, etc. , Particles such as iron-nickel alloy, iron-cobalt alloy, titanium oxide, aluminum oxide, copper oxide, magnesium oxide, lead oxide, zirconium oxide, silicon carbide, magnesium titanate, barium titanate, lithium titanate, lead titanate , Ceramic particles such as lead zirconate and lithium niobate, particles of high dielectric constant materials such as ammonium dihydrogen phosphate, potassium dihydrogen phosphate, and Rochelle salt, resin carriers in which the above magnetic particles are dispersed in a resin, etc. Is mentioned.

  Specific examples of the resin covering the carrier include (meth) acrylic polymer, styrene polymer, styrene- (meth) acrylic copolymer, olefin polymer (polyethylene, chlorinated polyethylene, polypropylene, etc.), Polyvinyl chloride, polyvinyl acetate, polycarbonate, cellulose resin, polyester resin, unsaturated polyester resin, polyamide resin, polyurethane resin, epoxy resin, silicone resin, fluororesin (polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride Etc.), phenol resin, xylene resin, diallyl phthalate resin, polyacetal resin, amino resin and the like. These resins can be used in combination of two or more.

  The particle diameter of the carrier is not particularly limited as long as the object of the present invention is not impaired, but is preferably 20 to 200 μm, more preferably 30 to 150 μm, as measured by an electron microscope.

The apparent density of the carrier is not particularly limited as long as the object of the present invention is not impaired. The apparent density varies depending on the carrier composition and surface structure, but typically 2.4 to 3.0 g / cm ³ is preferable.

  When the toner is used as a two-component developer, the toner content is preferably 1 to 20% by mass and more preferably 3 to 15% by mass with respect to the mass of the two-component developer. By setting the toner content in the two-component developer within such a range, it is possible to maintain an appropriate image density and to suppress contamination of the image forming apparatus and adhesion of toner to transfer paper by suppressing toner scattering.

[Method for producing positively chargeable electrostatic latent image developing toner]
Hereinafter, a method for producing a positively chargeable electrostatic latent image developing toner of the present invention will be described.

  The method for producing a positively chargeable electrostatic latent image developing toner of the present invention is not particularly limited as long as a mixture of a charge control agent containing a nitrogen atom and a charge control resin can be well dispersed in a binder resin. The toner can be appropriately selected from conventionally known toner production methods. As a suitable production method, for example, a mixture of a binder resin, a charge control resin and a charge control agent containing nitrogen, if necessary, components such as a colorant and a release agent are mixed and then melt-kneaded, The kneaded product obtained can be produced by pulverization and classification. The melt-kneading apparatus used for the production of the positively chargeable electrostatic latent image developing toner is not particularly limited, and can be appropriately selected from apparatuses used for melt-kneading thermoplastic resins. Specific examples of the melt-kneading apparatus include a uniaxial or biaxial extruder. The average particle size of the pulverized and classified toner is not particularly limited as long as the object of the present invention is not impaired, but generally 5 to 10 μm is preferable.

  The positively chargeable electrostatic latent image developing toner of the present invention has a charge having a domain diameter of 0.01 μm or more and less than 0.3 μm with respect to the number of charge control domains having a domain diameter of 0.01 μm or more as measured by a predetermined method. It is preferable that the charge control domains are formed in the binder resin so that the number% (fine domain ratio) of the control domains is 98 number% or more. In addition, it is preferable that the domain diameter at 99% by number from the smallest charge control domain dispersed in the binder resin is 0.01 to 0.3 μm.

  The fine domain ratio can be adjusted by appropriately adjusting the melt-kneading conditions. Specific examples of the method for increasing the microdomain ratio include reduction of the amount of material supplied to the melt-kneading apparatus and / or extension of the residence time of the material to be kneaded in the melt-kneading apparatus. When the melt kneading apparatus is an extruder, the residence time of the material to be kneaded can be extended by lowering the rotational speed of the shaft, using a melt kneading apparatus having a large L / D, or the like.

  The surface of the toner thus obtained may be treated with an external additive as necessary. The method for treating the toner with the external additive is not particularly limited, and can be appropriately selected from conventionally known methods for treating the external additive. Specifically, the processing conditions are adjusted so that the particles of the external additive are not embedded in the toner base particles, and the processing with the external additive is performed by a mixer such as a Henschel mixer or a Nauter mixer.

  The positively chargeable electrostatic latent image developing toner of the present invention described above is excellent in charge rising property, has excellent developability, and hardly causes problems such as toner scattering when printing is performed for a long time. Since it is excellent in durability, it is suitably used in various image forming apparatuses.

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not limited at all by the Example.

In Examples and Comparative Examples, the following RES1 and RES2 were used as resins included in the charge control domain.
RES1: Quaternary ammonium salt functional group-containing resin (FCA-196P (manufactured by Fujikura Kasei Co., Ltd.), the content of units derived from a monomer having a quaternary ammonium salt functional group is 5 mol%)
RES2: Polystyrene (G100C (manufactured by Toyo Styrene Co., Ltd.))

In Examples and Comparative Examples, the following CCA1 and CCA2 were used as charge control agents containing nitrogen atoms contained in the charge control domain.
CCA1: quaternary ammonium salt charge control agent, BONTRON P-51 (manufactured by Orient Chemical Co., Ltd.)
CCA2: azine compound charge control agent, BONTRON N-21 (manufactured by Orient Chemical Co., Ltd.)

[Example 1]
(Manufacture of charge control domain materials)
The charge control domain material was prepared according to the following method. 50 parts by mass of a quaternary ammonium salt functional group-containing resin (RES1) and 4 parts by mass of a quaternary ammonium salt charge control agent (CCA1) were dissolved in 500 parts by mass of toluene. The solvent of the resulting solution was removed at 50 ° C. under reduced pressure to obtain charge control domain material 1 (CCD-1).

(Manufacture of toner)
100 parts by mass of a polyester resin (binder resin, Tufton NE-7200 (manufactured by Kao Corporation)), 5.5 parts by mass of carnauba wax (release agent, C1 (manufactured by Kato Yoko Co., Ltd.)), carbon black (colorant, MA100 (Mitsubishi Chemical Corporation)) 4 parts by mass and charge control domain material 1 (CCD1) 8.8 parts by mass using a Henschel mixer (FM-20B (Nihon Coke Co., Ltd.)) at 240 rpm. And mixed. The obtained mixture was melt-kneaded using a twin screw extruder (PCM-30 (manufactured by Ikegai Co., Ltd.)) under the conditions of a material supply speed of 5 kg / hr, a shaft rotation speed of 160 rpm, and a cylinder temperature of 130 ° C. and then cooled. The obtained kneaded product was coarsely pulverized with a rotoplex mill (8/16 type (manufactured by Toa Kikai Co., Ltd.)), and then jet mill (ultrasonic jet mill type I (manufactured by Nippon Pneumatic Industry Co., Ltd.)). ), And the resulting finely pulverized product was classified with an elbow jet (EJ-LABO type (manufactured by Nippon Steel Mining Co., Ltd.)) to obtain a black toner having a volume average particle diameter of 6.8 μm. For 100 parts by mass of the obtained toner, as external additives, 1 part by mass of hydrophobic silica fine particles (RA-200H (manufactured by Nippon Aerosil Co., Ltd.)) and titanium oxide fine particles (ST-100 (manufactured by Titanium Industry Co., Ltd.)). ) 0.5 part by mass was added and mixed with a Henschel mixer (FM-20B (manufactured by Nippon Coke Co., Ltd.)) to obtain an externally treated toner.

  Using the obtained toner, the presence of a charge control domain on the toner surface was confirmed according to the following method. As a result, a drop mark of the charge control domain was observed on the toner surface, and it was confirmed that the charge control domain was formed on the toner surface.

<Charge control domain confirmation method>
After the toner 60 ± 0.1 mg was precisely weighed in a 50 ml sample tube, 10 ml of an aqueous ethanol solution (ethanol: water = 80: 20 (volume ratio)) was added to the sample tube. The sample tube was immersed in an ultrasonic cleaning machine (UT-105S (manufactured by Sharp Corporation)) in which water was applied so that the water level was 15 mm, and the ultrasonic wave was irradiated for 5 minutes with the scale at the maximum. The sample in the sample tube subjected to the ultrasonic treatment was filtered with a filter paper (No. 2 (manufactured by Toyo Roshi Kaisha, Ltd.)) to collect the toner, and the collected toner was vacuum-dried. The dried toner was obtained with a scanning electron microscope (JSM-7600F (manufactured by JEOL Ltd.)), and a secondary electrophotographic image (magnification 10,000) was obtained. It was confirmed whether or not the charge control domain was formed depending on whether or not the charge control domain was removed. For the toner of Example 1, a secondary electrophotographic image of the toner in which the charge control domain drop marks are formed is shown in FIG. According to FIG. 1, it is confirmed that the charge control domain is removed from the toner surface, and in the toner of Example 1, it can be seen that the charge control domain is formed on the toner surface.

  For the obtained toner, the number% of charge control domains having a domain diameter of 0.01 μm or more and less than 0.3 μm with respect to the number of charge control domains having a domain diameter of 0.01 μm or more (microdomain ratio) according to the following method. The domain diameter and area ratio of 99% by number from the smallest charge control domain were measured.

<Measurement of microdomain ratio, domain diameter and area ratio of charge control domain>
A kneaded product obtained by melt kneading with a twin-screw extruder in a toner production process is mounted on a polishing machine (Doctor Wrap ML-180SL (manufactured by Maruto)), and sand in the order of # 220, # 800, # 2000 Polished with paper. Furthermore, the surface of the kneaded product was mirror-finished by polishing using a diamond slurry having a particle diameter of 3 μm, a diamond slurry having a particle diameter of 1 μm, and alumina having a particle diameter of 0.1 μm in this order. A mirror-finished sample of the melt-kneaded material was heated at 58 ° C. for 12 hours, and then immersed in an aqueous ethanol solution (ethanol: water = 80: 20 (volume ratio)) to obtain an ultrasonic cleaner (UT-105S (Sharp Corporation). Sonication) for 5 minutes. By the ultrasonic treatment, the charge control domain on the sample surface is dropped, and a drop mark of the charge control domain is formed. After drying the ultrasonically treated sample, a secondary electrophotographic image (10,000 magnifications) of the surface of the sample was taken with a scanning electron microscope (JSM-7600F (manufactured by JEOL Ltd.)). The photographed SEM photograph was binarized by image analysis software (WinROOF (manufactured by Mitani Corp.)), and the diameter of 99% by number from the one with the smallest drop of the charge control domain and the charge on the surface of the sample. The area ratio of the control domain was measured. The measurement of the microdomain ratio, the domain diameter, and the area ratio of the charge control domain was performed on a charge control domain having a domain diameter of 0.01 μm or more.

  According to the above method, the domain diameters of 324 charge control domains were measured, and N1 to N29 (Nn is a charge control having a dispersion diameter of (0.01 × n) μm or more and (0.01 × (n + 1)) μm) The number of domains, and n is a positive integer of 1 or more.) The number% of the total number of charge control domains whose dispersion diameters are measured is calculated to calculate a charge control domain having a domain diameter of 0.01 μm or more. The number% of charge control tree domains having a domain diameter of 0.01 μm or more and less than 0.3 μm was obtained.

  Further, the minimum value of n is calculated such that the value of the number% of the sum of N1 to Nn with respect to the total number of charge control domains whose dispersion diameters are measured becomes 99% when the first decimal place is rounded off (0 .01 × n) μm was the domain diameter (μm) of 99% by number from the smallest charge control domain dispersed in the binder resin.

Further, using the obtained toner, developability and durability were evaluated according to the following methods.
<Developability>
The carrier used in the developer for TASKalfa500ci (multifunction machine (manufactured by Kyocera Mita Corporation)) and the externally-treated toner have a toner ratio of 12% by mass with respect to the total mass of the developer. The two-component developer was prepared by mixing for 30 minutes in a ball mill.
The obtained two-component developer is installed in a black developing unit of a multi-function machine (TASKalfa500ci) manufactured by Kyocera Mita Co., Ltd., and a voltage (ΔV) between the developing sleeve and the magnet roll is 250 V, and an alternating current is applied to the magnet roll. The voltage (Vpp) was set to 2.0 kV, copying was performed without paper, and a 3 cm × 3 cm solid image was developed on the intermediate transfer member. The toner on the intermediate transfer member is collected by a filter having a mesh size of 5 μm using a QM meter (MODEL 210HS-1: manufactured by Trek Japan Co., Ltd.), and the weight of the collected toner is measured. The toner development amount (mg / cm ² ) that is the toner amount per unit area in the solid image formed on the body was measured. Further, the charge amount of the toner was measured by a QM meter (MODEL 210HS-1: manufactured by Trek Japan Co., Ltd.). Regarding the toner development amount, a toner development amount of 0.8 mg / cm ² or more was determined to be good, and a toner development amount of less than 0.8 mg / cm ² was determined to be poor. Regarding the charge amount, 20 to 27 μC / g was determined to be good, and less than 20 μC / g and more than 27 μC / g were determined to be poor.

<Durability>
The multifunctional machine used for the evaluation of developability was set in a state where printing can be performed on paper, and a durability test was performed in which 10,000 sheets were printed at a printing rate of 5% in an environment of normal temperature and humidity (20 ° C., 60% RH). After the durability test, the weight of the toner scattered inside the multifunction machine was measured. Further, the charge amount of the toner after the durability test was measured by a QM meter (MODEL 210HS-1: manufactured by Trek Japan Co., Ltd.). Further, for the toner after the endurance test, the amount (% by mass) of the reversely charged toner, which is an index of toner scattering property, was measured using an espart analyzer (EST-III type (manufactured by Hosokawa Micron Corporation)). . Regarding the weight of the scattered toner, 100 mg or less was judged as good, and more than 100 mg was judged as bad. Regarding the charge amount of the toner, 12 to 27 μC / g was determined to be good, and less than 12 μC / g and more than 27 μC / g were determined to be defective. Regarding the amount of the reversely charged toner, 1% by mass or less was determined to be good, and more than 1% by mass was determined to be defective.

[Example 2]
An externally added toner was obtained in the same manner as in Example 1 except that the amount of charge control domain material 1 (CCD 1) used was changed to 16.5 parts by mass. The evaluation results of the fine domain ratio of the toner obtained in Example 2, the area ratio with respect to the domain diameter and toner cross-sectional area of 99% by number from the smallest charge control domain, developability, and durability are shown. Write in 1. The total number of charge control domains whose domain diameter was measured was 224.

Example 3
Externally added toner was obtained in the same manner as in Example 1 except that the amount of charge control domain material 1 (CCD1) used was changed to 4.4 parts by mass. The evaluation results of the fine domain ratio, the area ratio with respect to the domain diameter and toner cross-sectional area of 99% by number from the smallest charge control domain, developability, and durability of the toner obtained in Example 3 are shown. Write in 1. The total number of charge control domains whose domain diameter was measured was 203.

Example 4
(Manufacture of charge control domain materials)
The charge control domain material was prepared according to the following method. 50 parts by mass of a quaternary ammonium salt functional group-containing resin (RES1) and 5 parts by mass of an azine compound charge control agent (CCA2) were dissolved in 500 parts by mass of toluene. The solvent of the obtained solution was removed under reduced pressure at 50 ° C. to obtain charge control domain material 2 (CCD 2).

(Manufacture of toner)
Externally added toner was obtained in the same manner as in Example 1 except that the charge control agent domain material 1 (CCD1) was changed to the charge control domain material 2 (CCD2). The toner obtained in Example 4 shows the evaluation results of the microdomain ratio, the area ratio with respect to the domain diameter and the toner cross-sectional area of 99% by number from the smallest charge control domain, developability, and durability. Write in 1. The total number of charge control domains whose domain diameter was measured was 425.

Example 5
(Manufacture of charge control domain materials)
The charge control domain material was prepared according to the following method. 30 parts by mass of a quaternary ammonium salt functional group-containing resin (RES1), 23 parts by mass of polystyrene (RES2), and 4 parts by mass of a quaternary ammonium salt charge control agent (CCA1) were dissolved in 500 parts by mass of toluene. The solvent of the obtained solution was removed under reduced pressure at 50 ° C. to obtain a charge control domain material 3 (CCD3).

(Manufacture of toner)
Changing the charge control domain material from charge control agent domain material 1 (CCD1) to charge control domain material 3 (CCD3) and changing the amount of charge gain control domain material used from 8.8 parts by weight to 11.4 parts by weight Others were carried out in the same manner as in Example 1 to obtain an externally added toner. Table 5 shows the evaluation results of the toner obtained in Example 5, the fine domain ratio, the area ratio with respect to the domain diameter and the toner cross-sectional area of 99% by number from the smallest charge control domain, developability, and durability. Write in 1. The total number of charge control domains whose domain diameter was measured was 121.

[Comparative Example 1]
In place of charge control domain material 1 (CCD1), 8.0 parts by mass of quaternary ammonium salt functional group-containing resin (RES1) and 0.8 parts by mass of quaternary ammonium salt charge control agent (CCA1) are mixed. An externally added toner was obtained in the same manner as in Example 1 except that was used. Table 1 shows the evaluation results of the fine domain ratio of the toner obtained in Comparative Example 1, the area ratio with respect to the domain diameter and toner cross-sectional area of 99% by number from the smallest charge control domain, and developability. The total number of charge control domains whose domain diameter was measured was 67. Further, the toner obtained in Comparative Example 1 was not evaluated for durability because the developability was poor.

[Comparative Example 2]
An externally added toner was obtained in the same manner as in Comparative Example 1 except that the amount of the quaternary ammonium salt charge control agent (CCA1) was changed to 3.0 parts by mass. The evaluation results of the fine domain ratio, the area ratio with respect to the domain diameter and the toner cross-sectional area of 99% by number from the smallest charge control domain, developability, and durability of the toner obtained in Comparative Example 2 are shown. Write in 1. The total number of charge control domains whose domain diameter was measured was 84.

[Comparative Example 3]
An externally added toner is obtained in the same manner as in Example 1 except that 3.0 parts by mass of the quaternary ammonium salt charge control agent (CCA1) is used instead of the charge control domain material 1 (CCD1). It was. Table 1 shows the evaluation results of developability and durability of the toner obtained in Comparative Example 3.

[Comparative Example 4]
(Manufacture of charge control domain materials)
The charge control domain material was prepared according to the following method. 50 parts by mass of polystyrene (RES2) and 5 parts by mass of a quaternary ammonium salt charge control agent (CCA1) were dissolved in 500 parts by mass of toluene. The solvent of the resulting solution was removed at 50 ° C. under reduced pressure to obtain charge control domain material 4 (CCD 4).

(Manufacture of toner)
An externally added toner was obtained in the same manner as in Example 1 except that the charge control agent domain material 1 (CCD1) was changed to the charge control domain material 4 (CCD4). Table 1 shows the evaluation results of the fine domain ratio, the domain number of 99% by number from the smallest charge control domain, developability, and durability of the toner obtained in Comparative Example 4. The total number of charge control domains whose domain diameter was measured was 177.

  In the toners of Examples 1 to 5, a charge control agent containing a nitrogen atom was added to a charge control resin incompatible with the polyester resin, and then the charge control resin and the polyester resin were melt-kneaded to form a toner surface. Since the charge control domain is formed, the charge control agent containing a nitrogen atom contained in the charge control resin hardly distributes to the polyester resin. For this reason, in the toners of Examples 1 to 5, since the charge control agent is concentrated on the charge control domain on the toner surface, the toner exhibits good chargeability and excellent developability. In addition, since the charge control agent and the charge control resin have similar chemical structures and high affinity, the charge control agent present in the charge control domain does not easily fall off even when the toner is used for a long time. In 1 to 5, a toner having excellent durability was obtained.

  According to Comparative Example 1, when a toner is prepared by mixing a charge control agent containing a nitrogen atom and a charge control resin that are not uniformly mixed in advance with a polyester resin, the charge amount of the toner may be too high. I understand. For this reason, in Comparative Example 1, a toner having excellent developability could not be obtained.

  The toner of Comparative Example 2 is a toner in which the amount of the charge control agent containing nitrogen atoms is greatly increased with respect to the toner of Comparative Example 1, so that a large amount of the charge control agent is exposed on the toner surface and the developability is improved. An excellent toner was obtained. However, in the toner of Comparative Example 2, most of the charge control agent is exposed to the polyester resin portion on the toner surface, and the affinity between the polyester resin and the charge control agent is not so high. When used, the charge control agent easily falls off the toner surface. For this reason, the toner of Comparative Example 2 is inferior in durability.

  The toner of Comparative Example 3 was prepared by directly blending the polyester resin with a charge control agent having the same amount of nitrogen atoms as Comparative Example 2 without using the charge control resin. For this reason, since the charge control agent was exposed on the toner surface in substantially the same manner as in the toner of Comparative Example 2, a toner having excellent developability as in Comparative Example 2 was obtained. However, the toner of Comparative Example 3 is inferior in durability for the same reason as the toner of Comparative Example 2.

  In the toner of Comparative Example 4, after adding a charge control agent containing a nitrogen atom to polystyrene that is incompatible with the polyester resin, a mixture of the charge control agent and polystyrene, and the polyester resin are melt-kneaded, Since the charge control domain is formed on the surface, the charge control agent containing a nitrogen atom contained in polystyrene hardly distributes to the polyester resin. For this reason, the toner of Comparative Example 4 has good chargeability and excellent developability because the charge control agent is concentrated in the charge control domain on the toner surface. However, since the affinity between the charge control agent and polystyrene is not so high, the charge control agent easily falls off the charge control domain when the toner is used for a long period of time. For this reason, the toner of Comparative Example 4 is inferior in durability.

  Further, according to Examples 3 and 5, the domain number of 99% by number from the smallest charge control domain is 0.3 μm or less, and the area ratio of the charge control domain to the binder resin is 1 to 10 area%. In this case, it can be seen that a toner having excellent initial developability and excellent durability can be obtained.

  Furthermore, according to Examples 1 and 4, when the charge control agent containing a nitrogen atom is a quaternary ammonium salt, compared with the case of using a charge control material containing a nitrogen atom of another chemical structure (azine type). Thus, it can be seen that a toner that is particularly excellent in both developability and durability can be obtained.

Claims (5)

  The binder resin has a charge control domain composed of a mixture of a charge control agent containing a nitrogen atom and a charge control resin, the binder resin is a polyester resin, and the charge control resin is a quaternary ammonium salt functional group. And a quaternary ammonium salt functional group-containing resin that is a copolymer of a styrene and / or acrylic monomer, and the charge control domain is present on the toner surface. Toner for image development.   N1 to N29 (Nn is a dispersion diameter of (0.01 × n)) when the dispersion diameters of 50 or more charge control domains are measured using an image with a magnification of 10,000 times acquired by a scanning electron microscope. The total number of the charge control domains whose dispersion diameter is measured, the sum of which is the number of the charge control domains of μm or more (0.01 × (n + 1)) μm and n is a positive integer of 1 or more. 2. The positively charged electrostatic latent image developing according to claim 1, wherein the number% of the toner is 98% by number or more, and the ratio of the area of the charge control domain to the area of the cross section of the toner is 1 to 10 area%. toner.   The amount of the charge control agent containing nitrogen atoms contained in the toner is 1 to 10% by mass with respect to the total mass of the charge control agent containing nitrogen atoms and the charge control resin contained in the toner. The positively chargeable electrostatic latent image developing toner according to claim 1 or 2.   The positively chargeable electrostatic latent image developing toner according to claim 1, wherein the charge control agent containing a nitrogen atom is a quaternary ammonium salt.   In the quaternary ammonium salt functional group-containing resin, the amount of repeating units derived from the addition-polymerizable monomer having the quaternary ammonium salt functional group is the total repeating unit constituting the quaternary ammonium salt functional group-containing resin. 5. The positively chargeable electrostatic latent image developing toner according to claim 1, wherein the toner is 0.1 to 20 mol%.