JP4525410B2 - An electrophotographic toner, an electrophotographic developer, and an image forming method. - Google Patents

Description

  The present invention relates to an electrophotographic toner, an electrophotographic developer, and an image forming method that can be used in an electrophotographic apparatus using an electrophotographic process such as a copying machine, a printer, and a facsimile machine.

  Many methods are known as electrophotographic methods. In general, a latent image is electrically formed by various means on the surface of a photoreceptor (latent image holding body) using a photoconductive substance, and the formed latent image is developed with toner. After the image is formed, the toner image may be transferred to the surface of a transfer medium such as paper, optionally via an intermediate transfer body, and fixed by heating, pressurization, heat pressurization, solvent vapor, or the like. An image is formed through the process. Further, the toner remaining on the surface of the photoreceptor is cleaned by various methods as necessary, and is used again for developing the toner image.

  As a fixing technique for fixing the toner image transferred to the surface of the transfer target, a hot roll fixing in which the transfer target with the toner image transferred is inserted between a pair of rolls consisting of a heating roll and a pressure roll and fixed. The law is common. As a similar technique, a fixing method in which one or both of the rolls is replaced with a belt is also known. These techniques have the advantage that a fast and robust image is obtained, energy efficiency is high, and environmental damage due to volatilization of solvents and the like is small compared to other fixing methods.

  In recent years, from the viewpoint of energy saving, there is a tendency to save power in the fixing process, which occupies most of the power used in the image forming process. For high-speed image formation, the toner image is fixed in a short time, and the maximum power is inevitably increased. Therefore, power saving in the fixing step is particularly important.

  In order to achieve this requirement, lowering the fixing temperature of the toner itself leads to lowering the setting temperature of the fixing process, leading to a reduction in the maximum power consumption of the fixing process and a reduction in warm-up time from standby. It is also very important for energy saving because it leads to reduction of power consumption during standby.

  However, with conventional amorphous styrene acrylic resins and non-crystalline polyester resins, when the fixing temperature of the toner itself is lowered, its glass transition temperature is also lowered, causing toner blocking during storage or development. There is a problem that toner aggregates are generated due to stress in the container.

  In order to solve this problem, it has been proposed to use a crystalline resin having sharp melt properties. When a crystalline resin is used as a binder for toner, it is necessary to appropriately control the viscoelasticity in the fixing temperature region in order to achieve both fixing to paper and offset to a fixing member such as a heating roll. Crystalline polyester resins and the like can be raised as crystalline resins that satisfy this required characteristic. However, these resins have a portion that is easily polarized such as an ester bond in the resin, and the resistivity of the resin itself is low. There is a problem that the charging performance is low and the charging performance essential for the electrophotographic toner is low.

  As means for solving the above-mentioned problems, core particles (hereinafter abbreviated as “core particles”) made of amorphous resin or crystalline resin having a low glass transition point (or melting temperature) (60 ° C. or less) are formed. A so-called core-shell type toner in which a coating layer is provided on the surface of the core particles has been proposed.

  As a core-shell type toner, a styrene acrylic core material having a molecular weight of 3000 to 30000 and a glass transition point of 50 to 70 ° C. is encapsulated with a styrene shell material having a higher molecular weight and a high glass transition point. Toner prepared by suspending a core substance composed of saturated fatty acid or saturated alcohol having a melting point of 40 to 100 ° C. in water and encapsulating with resin fine particles (Japanese Patent Laid-Open No. 8-254853) However, there has been proposed a toner (Japanese Patent Laid-Open No. 9-258480) in which a thermally stable layer and a thermoplastic resin coating layer having a Tg of 65 ° C. or higher are laminated on the surface of low-viscosity resin particles.

In order to secure a wide fixing temperature range, it has been proposed to use a polyester having a naphthalene skeleton as a binder resin for a toner (Japanese Patent Laid-Open Nos. 2004-54176, 2004-12581, and 2004-4207). However, since these toners exhibit fixing performance due to the compatibility between the binder resin and the release agent, the heat resistance of the toner surface is not sufficient and the heat storage property and the inside of the image forming apparatus are not sufficient. There is a problem that aggregates are easily formed due to the stress, and stable image quality cannot be obtained.
JP-A-5-181301 JP-A-8-254853 JP-A-9-258480 JP 2004-54176 A JP2004-12581 JP2004-4207

  Therefore, in view of the above-mentioned conventional problems, the present invention has an object of the present invention, in an electrophotographic toner used in an image forming method such as an electrophotographic method, is excellent in low-temperature fixability, and has anti-blocking property during storage. An object of the present invention is to provide an electrophotographic toner that is excellent in blocking resistance against stress in an image forming apparatus, maintains an image density, and can stably provide an image free from fogging of a background portion. Another object of the present invention is to provide an electrophotographic developer using the electrophotographic toner and an image forming method.

The above problem is solved by the following means. That is,
The electrophotographic toner of the present invention is an electrophotographic toner having a core containing at least a colorant and a binder resin, and a shell layer containing a resin different from the binder resin on the surface of the core.
The shell layer is seen containing a polyester resin having a polymerization unit having a naphthalene skeleton,
The binder resin used for the core is a crystalline polyester resin,
The crystalline polyester resin has 0.3 to 10% by weight of a polymer unit having a naphthalene skeleton or a biphenyl skeleton, and 0.02 to 1.0% by weight of at least one of alkyl titanium, alkyl tin, and alkyl germanium. It is characterized by doing.

  In the electrophotographic toner of the present invention, it is preferable that the polyester resin used in the shell layer has 10 to 40 mol% of a polymer unit having the naphthalene skeleton. Moreover, it is suitable that the glass transition temperature of the said polyester resin used for the said shell layer is 65 degreeC or more.

  In the electrophotographic toner of the present invention, it is preferable that the storage elastic modulus (G ′) at 85 ° C. of the toner is 100 Pa to 100000 Pa and the loss elastic modulus (G ″) is larger than the storage elastic modulus.

  On the other hand, the electrophotographic developer of the present invention is characterized by including the above-described electrophotographic toner of the present invention and a carrier.

The image forming method of the present invention uses a latent image forming step for forming an electrostatic latent image on the surface of the latent image holding member and a developer carried on the developer carrying member, and forms the surface on the surface of the latent image holding member. A developing step of developing the electrostatic latent image formed to form a toner image, a transfer step of transferring the toner image formed on the surface of the latent image holding member to the surface of the transfer target, and a transfer to the surface of the transfer target A fixing step of thermally fixing the toner image formed,
The developer contains at least the electrophotographic toner of the present invention.

  According to the present invention, an electrophotographic toner used in an image forming method such as an electrophotographic method has excellent low-temperature fixability, excellent blocking resistance during storage, and excellent blocking resistance against stress in the image forming apparatus. It is possible to provide an electrophotographic toner that can maintain a density and can stably provide an image having no fogging or the like in the background portion. Then, an electrophotographic developer using the electrophotographic toner and an image forming method can be provided.

  The present invention will be described below. First, the electrophotographic toner of the present invention (hereinafter abbreviated as toner) will be described.

  The toner of the present invention is an electrophotographic toner having at least a core and a shell layer on the core surface. The shell layer includes a polyester resin having a polymer unit having a naphthalene skeleton, which is a resin different from the core binder resin.

  In the toner of the present invention, by using a polyester resin having a polymer unit having a naphthalene skeleton as a constituent component of the shell layer, it has excellent low-temperature fixability, blocking resistance during storage, and blocking resistance against stress in the image forming apparatus. The image density is excellent, the image density is maintained, and an image having no fogging or the like in the background portion can be stably obtained. The reason for this is unclear, but the presence of polymerized units having a conjugated double bond such as a naphthalene structure in the skeleton of the polyester resin increases the rigidity of the polymer chain, resulting in heat in the actual fixing device. It is presumed that the interaction between the pressure and the pressure makes the shell layer easy to collapse, and the inhibition of low-temperature fixability can be minimized. With regard to thermal storage and blocking in the image forming apparatus, it is not possible to prevent deterioration of the heat resistance of the surface due to compatibility by providing a phase separation structure between the toner inside and the surface as in the present invention. It is estimated that.

  Next, the toner shell layer will be described. The shell layer includes a polyester resin having a polymer unit having a naphthalene skeleton, which is a resin different from the binder resin for the core. The polyester resin is preferably contained in the shell layer as a main component, and specifically, for example, 50% by weight to 100% by weight is preferably contained in the resin constituting the shell layer.

  The polyester resin used in the shell layer preferably has 10 to 40 mol% of a polymer unit having a naphthalene skeleton, more preferably 20 to 40 mol%, still more preferably 25 to 35 mol%. When the number of polymer units having a naphthalene skeleton is less than 10 mol%, the above-described effect is reduced and the minimum fixing temperature may be increased. On the other hand, when it is 40 mol% or more, it is difficult to form the shell layer in a uniform film state, and heat storage properties and blocking in the image forming apparatus may be deteriorated.

  The glass transition temperature of the polyester resin used for the shell layer is preferably 65 ° C. or higher, more preferably 75 ° C. or higher, considering the stability to the environment where the toner is actually stored or used. The upper limit is preferably 95 ° C. or lower.

  The polyester resin used for the shell layer contains a polyester resin containing an acid-derived constituent component and an alcohol-derived constituent component, and contains other components as necessary. And as this acid origin component, it has a polymerization unit which has a naphthalene skeleton. The polyester resin is synthesized from an acid (dicarboxylic acid) component and an alcohol (diol) component. In the present invention, the “acid-derived component” is an acid component before the synthesis of the polyester resin. The “alcohol-derived constituent component” refers to a constituent site that was an alcohol component before the synthesis of the polyester resin.

  As the acid-derived constituent component, a polyvalent carboxylic acid having a naphthalene skeleton is preferably used. For example, naphthalenedicarboxylic acid and / or its lower alkyl ester, such as dimethyl naphthalate and diethyl naphthalate, can be raised. Other aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, and aliphatic carboxylic acids such as maleic anhydride, fumaric acid, succinic acid, alkenyl succinic anhydride, and adipic acid Examples thereof include alicyclic carboxylic acids such as acids and cyclohexanedicarboxylic acid, and one or more of these polyvalent carboxylic acids can be used.

  Examples of alcohol-derived components include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, glycerin, and other aliphatic diols, cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, and the like. Aromatic diols such as alicyclic diols, ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, and the like. One or more of these polyhydric alcohols can be used.

  Here, in the polyester resin used for the shell layer, examples of the polymer unit having a naphthalene skeleton as a copolymer component include 1,3-naphthalenediol, 1,5-naphthalenediol, 1,7-naphthalenediol, 1, Examples include 4-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid, but are not limited thereto.

  Next, the core will be described. The core includes at least a colorant and a binder resin. As this binder resin, known resins used for toners such as styrene-acrylic resins and polyester resins can be used. Two or more of these resins may be mixed and used.

  Among these binder resins, it is preferable to contain a crystalline resin in order to improve the constant temperature fixability. The melting point of the crystalline resin is preferably 50 ° C. to 100 ° C. in order to obtain constant temperature fixability. More preferably, it is 60 degreeC-80 degreeC.

  Styrene-acrylic resins and polyester resins having a low glass transition temperature are also preferable for obtaining low-temperature fixability. A preferable glass transition temperature is 30 ° C to 60 ° C. When a resin having a low glass transition temperature is used, it is preferable that the storage elastic modulus (G ″) of the toner at 55 ° C. is 1000000 Pa or more in order to maintain the heat storage property.

  Examples of the binder resin include conventionally known thermoplastic binder resins. Specifically, homopolymers or copolymers of styrenes such as styrene, parachlorostyrene, and α-methylstyrene (styrene resins). ); Methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, Homopolymers or copolymers of esters having vinyl groups such as 2-ethylhexyl methacrylate (vinyl resins); Homopolymers or copolymers of vinyl nitriles such as acrylonitrile and methacrylonitrile (vinyl resins) ; Vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether Homopolymers or copolymers (vinyl resins); homopolymers or copolymers of vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone (vinyl resins); ethylene, propylene, butadiene, isoprene Homopolymers or copolymers of olefins such as olefin resins (non-vinyl condensation resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and the like) And a graft polymer of a vinyl resin and a vinyl monomer. These resins may be used alone or in combination of two or more. Among these resins, vinyl resins and polyester resins are particularly preferable, and polyester resins are particularly preferable.

The polyester resin used for the core is a crystalline polyester resin, and the crystalline polyester resin is preferably one synthesized from a polyvalent carboxylic acid component and a polyhydric alcohol component.

  Examples of the polyvalent carboxylic acid component include oxalic acid, succinic acid, glutaric acid, adipic acid, peric acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12 -Aliphatic dicarboxylic acids such as dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, mesaconic acid Aromatic dicarboxylic acids such as dibasic acids such as, and the like, and anhydrides and lower alkyl esters thereof are also included, but not limited thereto.

  Examples of the trivalent or higher carboxylic acid include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and the like, and anhydrides thereof. And lower alkyl esters. These may be used individually by 1 type and may use 2 or more types together.

  As the polyhydric alcohol component, an aliphatic diol is preferable, and a linear aliphatic diol having 7 to 20 carbon atoms in the main chain portion is more preferable. When the aliphatic diol is branched, the crystallinity of the polyester resin is lowered and the melting point is lowered, so that toner blocking resistance, image storage stability, and low-temperature fixability may be deteriorated. Further, when the number of carbon atoms is less than 7, when the polycondensation with aromatic dicarboxylic acid is performed, the melting point becomes high and fixing at low temperature may be difficult. On the other hand, when the number exceeds 20, it is difficult to obtain practical materials. easy. The carbon number is more preferably 14 or less.

  Specific examples of the aliphatic diol suitably used for the synthesis of the crystalline polyester resin used for the core include ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,5-pentane. Diol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,14-eicosandecanediol, and the like, but are not limited thereto. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferable in view of availability.

  Examples of the trivalent or higher alcohol include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like. These may be used individually by 1 type and may use 2 or more types together.

  Among the polyhydric alcohol components, the content of the aliphatic diol component is preferably 80 mol% or more, and more preferably 90% or more. If the content of the aliphatic diol component is less than 80 mol%, the crystallinity of the polyester resin is lowered and the melting point is lowered, so that toner blocking resistance, image storage stability, and low-temperature fixability may be deteriorated. is there.

Crystalline polyester resin used in the core has a polymerization unit having a naphthalene skeleton or a biphenyl skeleton (monomer), Ru and alkyl titanium, alkyltin, including binding-crystalline polyester resin der at least one alkyl germanium . The reason is not clear, but this configuration realizes low-temperature fixing, especially when it is fixed on coated paper or cardboard, and it has excellent image strength with respect to writing resistance, and images can be stored even for long-term storage. Cracks are less likely to occur.

  The reason for this is not clear, but by using an aliphatic crystalline polyester resin in which an aromatic monomer is copolymerized and adding alkyl titanium, alkyl tin, or alkyl germanium to the resin, alkyl titanium, alkyl tin , It is speculated that the molecular chain of alkyl germanium is entangled in the resin, so it has excellent strength against pulling like cracks, and cracks will not occur even for long-term storage

Crystal polyester resin that is used in the core preferably has a polymerization unit having a naphthalene skeleton or a biphenyl skeleton 0.3 to 10 wt%, more preferably 0.5 to 8.0 wt%, more preferably Is 1.0 to 7.0% by weight. If this polymerized unit is less than 0.3% by weight, the melting point may be lowered and the rigidity may be lowered due to disorder of the crystalline structure. In particular, when fixing to coated paper or cardboard, sufficient image strength can be obtained. It may not be possible. On the other hand, if it exceeds 10% by weight, the characteristics of the aromatic component are largely reflected, and the fixed image may become brittle.

Crystal polyester resin that is used in the core, at least one alkyl titanium, alkyl tin and alkyl germanium, 0. 02 to 1.0 you content wt%, but more preferably 0.1 to 1.0 wt%, more preferably from 0.2 to 0.8 wt%. When this content is less than 0.02% by weight, it is difficult to sufficiently exert the force to suppress the generation of cracks. On the other hand, if the amount exceeds 1.0% by weight, air entrainment may occur remarkably and cracks may occur.

In crystal polyester resin that is used in the core, the polymerization unit having a naphthalene skeleton is a copolymer component, for example, 1,3-naphthalene, 1,5-naphthalene diol, 1,7-naphthalene diol, 1,4 -Naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, etc. are mentioned, but not limited thereto. On the other hand, examples of polymerized units having a biphenyl skeleton as a copolymer component include 2,2′-biphenol, 4,4′-biphenol, biphenyl-2,2′-dicarboxylic acid, and biphenyl-4,4′-dicarboxylic acid. However, this is not a limitation.

In crystal polyester resin that is used in the core, alkyl titanium, alkyltin, the alkyl germanium, such as methyl titanium oxide, ethyl titanium oxide, propyl titanium oxide, butyl titanium oxide, dimethyl titanium oxide, diethyl titanium oxide, dipropyl titanium oxide , Dibutyl titanium oxide, trimethyl titanium oxide, triethyl titanium oxide, tripropyl titanium oxide, tributyl titanium oxide, methyl tin oxide, ethyl tin oxide, propyl tin oxide, butyl tin oxide, dimethyl tin oxide, diethyl tin oxide, dipropyl tin oxide, Dibutyltin oxide, trimethyltin oxide, triethyltin oxide, tripropyltin oxide, tributyltin Xoxide, methyl germanium oxide, ethyl germanium oxide, propyl germanium oxide, butyl germanium oxide, dimethyl germanium oxide, diethyl germanium oxide, dipropyl germanium oxide, dibutyl germanium oxide, trimethyltigermanium oxide, triethyl germanium oxide, tripropyl germanium oxide, tributyl Examples thereof include germanium oxide, but are not limited thereto.

  An amorphous polyester resin can also be used as the binder resin used for the core. As a monomer component of this non-crystalline polyester resin, for example, a conventionally known divalent or trivalent monomer component as described in Polymer Data Handbook: Basics (Science of Polymer Science: Bafukan) There are the above carboxylic acids and divalent or trivalent or higher alcohols. Specific examples of these monomer components include divalent carboxylic acids such as succinic acid, glutaric acid, adipic acid, peric acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, and naphthalene-2. , 6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, cyclohexanedicarboxylic acid, malonic acid, mesaconic acid, and other dibasic acids, and their anhydrides and their lower alkyl esters, maleic acid, fumaric acid, itaconic acid And aliphatic unsaturated dicarboxylic acids such as citraconic acid. Examples of the trivalent or higher carboxylic acid include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and the like, and anhydrides thereof. And lower alkyl esters. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the divalent alcohol include bisphenol A, hydrogenated bisphenol A, ethylene oxide or (and) propylene oxide adduct of bisphenol A, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, ethylene glycol, diethylene glycol, Examples include propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, and neopentyl glycol. Examples of the trivalent or higher alcohol include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like. These may be used individually by 1 type and may use 2 or more types together. If necessary, monovalent acids such as acetic acid and benzoic acid, and monovalent alcohols such as cyclohexanol and benzyl alcohol can be used for the purpose of adjusting the acid value and the hydroxyl value.

As described above, the polyester resin used for the core and shell layers described above can be used in any combination of the above monomer components, for example, polycondensation (chemical doujin), polymer experiment (polycondensation and polyaddition: Kyoritsu Publishing) It can synthesize | combine using the conventionally well-known method as described in a polyester resin handbook (Nikkan Kogyo Shimbun) etc., and can use the transesterification method, the direct polycondensation method, etc. individually or in combination. Moreover, when using the said polyester resin as binder resin, it is preferable to use the thing of the range whose weight average molecular weight Mw is 5,000-40,000 and whose number average molecular weight Mn is 2,000-10,000.

  Moreover, there is no restriction | limiting in particular as a manufacturing method of a polyester resin, It can manufacture with the general polyester polymerization method which makes an acid component and an alcohol component react, For example, a direct polycondensation, a transesterification method, etc. are used for a monomer. Depending on the type, it will be manufactured separately. The molar ratio (acid component / alcohol component) when the acid component reacts with the alcohol component varies depending on the reaction conditions and the like, and cannot be generally stated, but is usually about 1/1.

  The production of the polyester resin can be carried out at a polymerization temperature of 180 to 230 ° C., and the reaction system is reduced in pressure as necessary, and the reaction is carried out while removing water and alcohol generated during the condensation.

  If the monomer is not dissolved or compatible at the reaction temperature, a high boiling point solvent is added as a solubilizer and dissolved. In the polycondensation reaction, the dissolution auxiliary solvent is distilled off. In the case where a monomer having poor compatibility is present in the copolymerization reaction, the monomer having poor compatibility and the monomer and the acid or alcohol to be polycondensed are condensed in advance and then polycondensed together with the main component.

  Catalysts that can be used in the production of the polyester resin include alkali metal compounds such as sodium and lithium, alkaline earth metal compounds such as magnesium and calcium, metal compounds such as zinc, manganese, antimony, titanium, tin, zirconium, and germanium, A phosphorous acid compound, a phosphoric acid compound, an amine compound, etc. are mentioned, Specifically, the following compounds are mentioned.

  For example, sodium acetate, sodium carbonate, lithium acetate, lithium carbonate, calcium acetate, calcium stearate, magnesium acetate, zinc acetate, zinc stearate, zinc naphthenate, zinc chloride, manganese acetate, manganese naphthenate, titanium tetraethoxide, titanium Tetrapropoxide, titanium tetraisopropoxide, titanium tetrabutoxide, antimony trioxide, triphenylantimony, tributylantimony, tin formate, tin oxalate, tetraphenyltin, dibutyltin dichloride, dibutyltin oxide, diphenyltin oxide, zirconium tetrabutoxide, naphthene Zirconate, zirconyl carbonate, zirconyl acetate, zirconyl stearate, zirconyl octylate, germanium oxide, triphenyl Phosphite, tris (2,4-di -t- butyl-phenyl) phosphite, ethyltriphenylphosphonium bromide, triethylamine, compounds such as triphenyl amine.

  On the other hand, there is no restriction | limiting in particular as a coloring agent, A well-known coloring agent is mentioned, It can select suitably according to the objective. One type of pigment may be used alone, or two or more types of pigments of the same type may be mixed and used. Two or more different types of pigments may be mixed and used.

  Specific examples of the colorant include carbon blacks such as furnace black, channel black, acetylene black, and thermal black, inorganic pigments such as bengara, aniline black, bitumen, titanium oxide, and magnetic powder, fast yellow, and monoazo yellow. , Disazo yellow, pyrazolone red, chelate red, brilliant carmine (3B, 6B, etc.), azo pigments such as para brown, phthalocyanine pigments such as copper phthalocyanine, metal-free phthalocyanine, flavantron yellow, dibromoanthrone orange, perylene red, quinacridone red And condensed polycyclic pigments such as dioxazine violet.

  Chrome Yellow, Hansa Yellow, Benzidine Yellow, Slen Yellow, Quinoline Yellow, Permanent Orange GTR, Pyrazolone Orange, Vulcan Orange, Watch Young Red, Permanent Red, Dupont Oil Red, Resol Red, Rhodamine B Lake, Lake Red C, Rose Various pigments such as Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Phthalocyanine Green, Malachite Green Oxalate, Para Brown; Acridine, Xanthene, Azo, Benzoquinone, Azine, Anthraquinone, dioxazine, thiazine, azomethine, indigo, thioindigo, phthalocyanine, aniline black , Polymethine dyes, triphenylmethane dyes, diphenylmethane dyes, thiazole type, various dyes such as xanthene; and the like. You may mix black pigments, such as carbon black, and dye to such an extent that transparency is not reduced to these colorants. Moreover, a disperse dye, an oil-soluble dye, etc. are mentioned.

The content of the colorant is preferably 1 to 30 parts by weight with respect to 100 parts by weight of the binder resin, but it is as much as possible in such a numerical range as long as the smoothness of the image surface after fixing is not impaired. preferable. Increasing the content of the colorant is advantageous in that the thickness of the image can be reduced when an image having the same density is obtained, which is effective in preventing offset.
In addition, by appropriately selecting the type of the colorant, each color toner such as yellow toner, magenta toner, cyan toner, and black toner can be obtained.

  Next, other components used for both the core and the shell layer of the electrophotographic toner will be described.

  There is no restriction | limiting in particular as another component, According to the objective, it can select suitably, For example, well-known various additives, such as an inorganic fine particle, an organic fine particle, a charge control agent, a mold release agent, etc. are mentioned. The other components may be used not only as added to the core but also as an external additive for toner particles.

  Inorganic fine particles are generally used for the purpose of improving the fluidity of toner particles. Examples of the inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, cerium chloride. , Bengara, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, silicon nitride and the like. Among these, silica fine particles are preferable, and silica fine particles that have been hydrophobized are particularly preferable.

  The average primary particle size (number average particle size) of the inorganic fine particles is preferably 1 to 1000 nm, and the addition amount (external addition) is 0.01 to 20 parts by weight with respect to 100 parts by weight of the toner particles. preferable.

  Organic fine particles are generally used for the purpose of improving cleaning properties and transferability. Examples of the organic fine particles include fine particles such as polystyrene, polymethyl methacrylate, and polyvinylidene fluoride.

  The charge control agent is generally used for the purpose of improving the chargeability. Examples of the charge control agent include salicylic acid metal salts, metal-containing azo compounds, nigrosine and quaternary ammonium salts.

  A mold release agent is generally used for the purpose of improving mold release properties. Specific examples of the release agent include low molecular weight polyolefins such as polyethylene, polypropylene, and polybutene; silicones having a softening point by heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, and stearic acid amide Plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil; animal waxes such as beeswax; montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, etc. Mineral / petroleum waxes; ester waxes such as fatty acid esters, montanic acid esters, and carboxylic acid esters. In this invention, these mold release agents may be used individually by 1 type, and may use 2 or more types together.

  The addition amount of these release agents is preferably 0.5 to 50% by weight, more preferably 1 to 30% by weight, and still more preferably 5 to 15% by weight with respect to the total amount of toner particles. is there. If it is less than 0.5% by weight, there is no effect of adding a release agent, and if it is 50% by weight or more, the charging property is likely to be affected, or the toner particles are easily destroyed inside the developing machine, so that the mold release. In addition to the effect that the agent is spent on the carrier and the charge is likely to decrease, for example, when color toner is used, the image surface tends to be insufficiently oozed out at the time of fixing. Since the release agent tends to stay in the film, the transparency is deteriorated, which is not preferable.

  In the toner of the present invention, a chargeable substance may be further chemically or physically attached to the surface of the toner particles. Further, fine particles such as metal, metal oxide, metal salt, ceramic, resin, and carbon black may be externally added for the purpose of improving charging property, conductivity, powder fluidity, lubricity and the like.

  Next, preferred characteristics of the toner of the present invention will be described. In order to improve the fixing performance at a constant temperature, the toner of the present invention preferably has a storage elastic modulus (G ′) at 85 ° C. of 100 Pa to 100,000 Pa and a loss elastic modulus (G ″) larger than the storage elastic modulus. The storage elastic modulus (G ′) is preferably 2000 Pa or more and 90000 Pa or less, and more preferably 5000 Pa or more and 50000 Pa or less.

  Further, the volume average particle size of the toner particles according to the toner of the present invention is preferably 1 to 20 μm, more preferably 2 to 8 μm, and the number average particle size is preferably 1 to 20 μm and preferably 2 to 8 μm. More preferred.

  Here, the volume average particle diameter and the number average particle diameter can be determined by measuring with a 50 μm aperture diameter using, for example, a Coulter counter [TA-II] type (manufactured by Coulter). At this time, the measurement is performed after the toner is dispersed in an electrolyte aqueous solution (isoton aqueous solution) and dispersed by ultrasonic waves for 30 seconds.

  Next, a method for producing the toner of the present invention will be described below including a method for forming a core-shell structure.

  In the toner manufacturing method of the present invention, first, core particles corresponding to a core are prepared. The method for producing the core particles is preferably based on a wet granulation method. Suitable examples of the wet granulation method include known melt suspension methods, emulsion aggregation methods, and dissolution suspension methods. Hereinafter, the emulsion aggregation method will be described as an example.

  The emulsion aggregation method emulsifies the specific binder resin and, if necessary, other binder resins to form emulsion particles (droplets), and forms aggregates of the emulsion particles (droplets). An aggregating step, and a fusing step of fusing and aggregating the aggregate.

-Emulsification process-
The emulsification process will be described by taking the specific polyester resin as an example. In the emulsification step, emulsified particles (droplets) of a specific polyester resin give a shearing force to a solution obtained by mixing an aqueous medium and a mixed liquid (polymer liquid) containing a polyester resin and, if necessary, a colorant. Is formed.

  At that time, the viscosity of the polymer liquid can be lowered to form emulsified particles by heating or dissolving the polyester resin in an organic solvent. Moreover, a dispersing agent can also be used for stabilization of emulsified particles and thickening of the aqueous medium. Hereinafter, such a dispersion of emulsified particles may be referred to as a “resin particle dispersion”.

  Examples of the dispersant include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium polyacrylate, and sodium polymethacrylate, sodium dodecylbenzenesulfonate, sodium octadecylsulfate, and sodium oleate. , Anionic surfactants such as sodium laurate and potassium stearate, cationic surfactants such as laurylamine acetate, stearylamine acetate and lauryltrimethylammonium chloride, zwitterionic surfactants such as lauryldimethylamine oxide, poly Nonoxy such as oxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl amine, etc. Surfactants such as emissions surfactant, tricalcium phosphate, aluminum hydroxide, calcium sulfate, calcium carbonate, and inorganic compounds such as barium carbonate.

  When an inorganic compound is used as the dispersant, a commercially available product may be used as it is, but for the purpose of obtaining fine particles, a method of producing fine particles of an inorganic compound in the dispersant may be employed. As a usage-amount of a dispersing agent, 0.01-20 weight part is preferable with respect to 100 weight part of said polyester resins (binder resin).

  In the emulsification step, the polyester resin is copolymerized with a dicarboxylic acid having a sulfonic acid group (that is, a suitable amount of a dicarboxylic acid-derived component having a sulfonic acid group is included in the acid-derived component). And dispersion stabilizers, such as surfactant, can be reduced, or an emulsified particle can be formed even if it does not use it.

  Examples of the organic solvent include ethyl acetate and toluene, which are appropriately selected according to the polyester resin. The organic solvent is used in an amount of 50 to 5000 parts by weight based on 100 parts by weight of the total amount of the polyester resin and other monomers used as necessary (hereinafter sometimes referred to simply as “polymer”). Is preferable, and 120 to 1000 parts by weight is more preferable. In addition, a colorant can be mixed before forming the emulsified particles. The colorant used is the same as already described in the section “Colorant” of the electrophotographic toner of the present invention.

  Examples of the emulsifier used when forming the emulsified particles include a homogenizer, a homomixer, a pressure kneader, an extruder, and a media disperser. The size of the emulsified particles (droplets) of the polyester resin is preferably 0.01 to 1 μm, more preferably 0.03 to 0.3 μm in terms of the average particle size (volume average particle size), and 0.03 to 0.03. 0.4 μm is more preferable.

  As a method for dispersing the colorant, any method such as a general shearing method such as a rotary shearing homogenizer, a ball mill having a medium, a sand mill, or a dyno mill can be used, and is not limited at all.

  If necessary, an aqueous dispersion of these colorants can be prepared using a surfactant, or an organic solvent dispersion of these colorants can be prepared using a dispersant. Hereinafter, such a colorant dispersion may be referred to as a “colored particle dispersion”. As the surfactant and the dispersing agent used for dispersion, the same dispersing agents that can be used when dispersing the polyester resin can be used.

  The addition amount of the colorant is preferably 1 to 20% by weight, more preferably 1 to 10% by weight, still more preferably 2 to 10% by weight, based on the total amount of the polymer. It is especially preferable to set it as 2 to 7 weight%.

  When the colorant is mixed in the emulsification step, the polymer and the colorant can be mixed by mixing the colorant or the organic solvent dispersion of the colorant with the organic solvent solution of the polymer.

-Aggregation process-
In the aggregation step, the obtained emulsified particles are aggregated by heating at a constant temperature to form an aggregate. Formation of the aggregate of the emulsified particles is performed by acidifying the pH of the emulsion under stirring. The pH is preferably 2 to 6, more preferably 2.5 to 5, and still more preferably 3 to 4.5. At this time, it is also effective to use a flocculant.

  As the flocculant to be used, a surfactant having a reverse polarity to the surfactant used for the dispersant, an inorganic metal salt, and a metal complex having a valence of 2 or more can be preferably used. In particular, the use of a metal complex is particularly preferable because the amount of the surfactant used can be reduced and the charging characteristics are improved.

  Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and inorganic such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include metal salt polymers. Among these, an aluminum salt and a polymer thereof are particularly preferable. In order to obtain a sharper particle size distribution, the valence of the inorganic metal salt is bivalent than monovalent, trivalent than bivalent, trivalent than trivalent, and tetravalent than trivalent. The inorganic metal salt polymer is more suitable.

-Fusion process-
In the fusion step, under the same stirring as in the aggregation step, the pH of the suspension of the aggregate is set in the range of 5 to 10 to stop the progress of the aggregation, and the melting point of the polyester resin or the glass transition temperature or higher. The aggregates are fused and fused by heating at a temperature. The heating time may be as long as the fusion is sufficiently performed, and may be performed for about 0.5 to 10 hours.

  The fused particles obtained by fusing can be made into toner particles through a solid-liquid separation process such as filtration and, if necessary, a washing process and a drying process. In this case, in order to ensure sufficient charging characteristics and reliability as a toner, it is preferable to sufficiently wash in the washing step.

-Drying process-
In the drying process, an arbitrary method such as a normal vibration type fluidized drying method, a spray drying method, a freeze drying method, or a flash jet method can be adopted. It is desirable that the toner particles have a moisture content after drying of 1.0% or less, preferably 0.5% or less.

  Next, when producing latex adhering particles by adhering resin latex (constituting resin of the shell layer) to the core particles produced by the above method, the solid content concentration is preferably 15 to 50%, and 30 to 40 % Is more preferable. When the solid content concentration is less than 15%, the resin latex is difficult to adhere to the core particles, and when the solid content concentration is higher than 50% by weight, the viscosity of the resin latex dispersion is too high, and a large amount of energy is required for stirring. It becomes. The latex diameter is preferably 0.02 μm to 0.2 μm. Preferably, it is 0.04 μm to 0.12 μm. It is preferable that the pH of the liquid during the production of latex-adhering particles is a stable pH of the resin latex used. It is preferable to adjust the pH around emulsification around plus or minus 2.

  An aggregating agent can be used in combination to assist in the formation of latex adhered particles. Specific examples of the flocculant that can be used here are as described above.

Since the amount of the flocculant used varies depending on the type of flocculant, it is determined in accordance with the flocculant cohesive force. If too much is added, the toner particles will aggregate, and if less, the shell layer tends to peel off. When a metal salt is used as the flocculant, generally, when the valence of the metal salt is large, the cohesive force is strong and the amount of the flocculant is small.
For example, in the case of polyaluminum chloride, the use of about 0.01 to 0.15% with respect to the shell material is appropriate.

  The amount of the resin latex varies depending on the core particle diameter, and the amount is adjusted so as to obtain a desired film thickness. When the core particle diameter is in the range of 3 to 13 μm, 5 to 60% by weight of latex is used. Of course, the particle size of the resin latex is also taken into consideration.

  When forming latex-adhered particles, if the amount of resin latex is small or the latex is large, the latex-adhered particles are difficult to be uniform, or a place that is not partially covered with resin latex is formed. If the amount is too large, the thickness of the entire shell layer increases, so the fixing temperature becomes high, so low temperature fixing cannot be achieved, and if the diameter of the resin latex is too small, the aggregation of the particles proceeds and the uniformity Becomes lower.

  The latex-adhered particles thus obtained are heated at around 50 ° C., and a shell layer is formed by semi-adhering the interface with the core particles or the resin latex. Thereafter, the toner particles with the shell layer semi-fused are taken out of the reactor, washed and dried. When drying, it is effective for forming the shell layer to slowly dehydrate at a temperature not higher than the glass transition point Tg of the resin forming the shell layer. An oven dryer or a flash jet dryer is effective. If a part of the resin latex is not yet melted even after this drying step, it is also effective to further smooth the uneven surface using mechanical force.

  As described above, the method for producing an electrophotographic toner according to the present invention includes an aggregation step in which a latex latex is adhered to the core particles to form latex adhered particles, and the latex adhered particles are heated to form the shell layer. A melting step.

  Next, the electrophotographic developer of the present invention (hereinafter abbreviated as developer) will be described. The developer of the present invention contains at least the toner of the present invention. The toner of the present invention can be used as it is as a one-component developer. The developer of the present invention may be a two-component developer composed of a carrier and a toner. Hereinafter, the two-component developer will be described.

  The carrier that can be used in the two-component developer is not particularly limited, and a known carrier can be used. For example, a resin-coated carrier having a resin coating layer on the surface of the core material can be exemplified. Further, a resin-dispersed carrier in which a conductive material or the like is dispersed in a matrix resin may be used.

  Coating resins and matrix resins used for carriers include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic. Examples thereof include, but are not limited to, acid copolymers, straight silicone resins composed of organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenol resins, and epoxy resins.

  Examples of the conductive material include metals such as gold, silver and copper, carbon black, titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, tin oxide, and carbon black. It is not limited.

  Examples of the carrier core material include magnetic metals such as iron, nickel, and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. However, in order to use the carrier for the magnetic brush method, a magnetic material is used. Preferably there is.

  The volume average particle size of the core material of the carrier is generally 10 to 500 μm, preferably 30 to 100 μm.

  In order to coat the surface of the core material of the carrier with a resin, there may be mentioned a method of coating with a coating layer forming solution in which the coating resin and, if necessary, various additives are dissolved in an appropriate solvent. The solvent is not particularly limited and may be appropriately selected in consideration of the coating resin to be used, coating suitability, and the like.

  Specific resin coating methods include an immersion method in which the carrier core material is immersed in the coating layer forming solution, a spray method in which the coating layer forming solution is sprayed onto the surface of the carrier core material, and the carrier core material is fluidized air. And a kneader coater method in which the carrier core material and the coating layer forming solution are mixed in a kneader coater and the solvent is removed in a kneader coater.

  The mixing ratio (weight ratio) between the toner and the carrier in the two-component developer is preferably in the range of toner: carrier = 1: 100 to 30: 100, and more preferably in the range of about 3: 100 to 20: 100.

  Next, the image forming method of the present invention will be described. The image forming method of the present invention is formed on the surface of the latent image holding body using a latent image forming step of forming an electrostatic latent image on the surface of the latent image holding body and a developer carried on the developer carrying body. A developing process for developing the electrostatic latent image to form a toner image, a transfer process for transferring the toner image formed on the surface of the latent image holding body to the surface of the transfer target, and the image transferred to the surface of the transfer target And a fixing step of heat-fixing the toner image, wherein the developer contains at least the electrophotographic toner of the present invention. The developer may be either a one-component system or a two-component system.

  As each of the above steps, a known step in the image forming method can be used.

As the latent image holding member, for example, an electrophotographic photosensitive member and a dielectric recording member can be used.
In the case of an electrophotographic photosensitive member, the surface of the electrophotographic photosensitive member is uniformly charged by a corotron charger, a contact charger or the like and then exposed to form an electrostatic latent image (latent image forming step). Next, the toner particles are adhered to the electrostatic latent image in contact with or in proximity to a developing roll having a developer layer formed on the surface, thereby forming a toner image on the electrophotographic photosensitive member (developing step). The formed toner image is transferred onto the surface of a transfer medium such as paper using a corotron charger or the like (transfer process). Further, the toner image transferred to the surface of the transfer target is heat-fixed by a fixing device, and a final toner image is formed.

  In order to prevent offset and the like during heat fixing by the fixing machine, a release agent is usually supplied to a fixing member in the fixing machine, but when the toner contains a release agent, No release agent is supplied from the fixing machine.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, these examples do not limit the present invention. In this example, “parts” means “parts by weight” unless otherwise specified.

  In addition, each measurement in a present Example was performed as follows.

(Measurement method of particle size and particle size distribution)
The particle size and particle size distribution measurement in the present invention will be described. When the particles to be measured in the present invention are 2 μm or more, a Coulter counter TA-II type (manufactured by Beckman-Coulter) was used as the measuring apparatus, and ISOTON-II (manufactured by Beckman-Coulter) was used as the electrolyte.

  As a measuring method, 0.5 to 50 mg of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate as a dispersant. This was added to 100 to 150 ml of the electrolytic solution.

  The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute, and the particle size distribution of particles of 2 to 60 μm is measured using the Coulter counter TA-II with an aperture diameter of 100 μm. Volume average distribution and number average distribution were determined. The number of particles to be measured was 50,000.

  The particle size distribution of the toner in the present invention was determined by the following method. For the particle size range (channel) obtained by dividing the measured particle size distribution, a volume cumulative distribution is drawn from the smaller particle size, and the volume average particle size of 16% is defined as D16, and the volume average of 50% is accumulated. The particle size is defined as D50. Furthermore, the volume average particle diameter that is 84% cumulative is defined as D84.

The volume average particle diameter in the present invention is D50, and GSD was calculated by the following equation.
Formula: GSD = (D84 / D16) ^0.5
Similarly, a number cumulative distribution is drawn from the smaller particle size to the divided particle size range (channel) of the measured particle size distribution, and the particle size at 50% accumulation is defined as the number average particle size.

  Moreover, when the particle | grains to measure in this invention are less than 2 micrometers, it measured using the laser diffraction type particle size distribution measuring apparatus (LA-700: made by Horiba, Ltd.). As a measurement method, a sample in a dispersion is adjusted to have a solid content of about 2 g, and ion exchange water is added thereto to make about 40 ml. This is put into the cell until an appropriate concentration is reached, waits for about 2 minutes, and is measured when the concentration in the cell becomes almost stable. The obtained volume average particle diameter for each channel was accumulated from the smaller volume average particle diameter, and the volume average particle diameter was determined to be 50%.

(Measurement method of weight average molecular weight)
The weight average molecular weight is measured under the following conditions. GPC uses “HLC-8120GPC, SC-8020 (manufactured by Tosoh Corporation)”, and the column uses two “TSKgel, SuperHM-H (6.0 mm ID × 15 cm, manufactured by Tosoh Corporation)” THF (tetrahydrofuran) was used as an eluent. As experimental conditions, the sample concentration was 0.5%, and the flow rate was 0.6 ml / min. The experiment was conducted using a sample injection amount of 10 μl, a measurement temperature of 40 ° C., and an IR detector. The calibration curve is “polystylen standard sample TSK standard” manufactured by Tosoh Corporation: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A-2500”. ”,“ F-4 ”,“ F-40 ”,“ F-128 ”, and“ F-700 ”.

(Measuring method of melting point and glass transition temperature)
Melting | fusing point and glass transition temperature were calculated | required from the main body maximum peak measured based on ASTMD3418-8.
DSC-7 manufactured by Perkin Elmer Co. can be used for measurement of the main maximum peak. The temperature correction of the detection part of this apparatus uses the melting point of indium and zinc, and the correction of heat quantity uses the heat of fusion of indium. As the sample, an aluminum pan was used, an empty pan was set as a control, and the measurement was performed at a heating rate of 10 ° C./min.

(Measurement of crystallinity)
Regarding the presence or absence of crystallinity in the resin of the present invention, the heat absorption curve measured by the above method is a straight line obtained by extending the base line on the low temperature side to the high temperature side and the melting peak (endothermic peak) according to the definition of the melting temperature of JIS K7121. The intersection of the tangent line (melting start temperature) drawn at the point where the gradient becomes the maximum on the low-temperature side curve and the straight line extending the high-temperature base line to the low-temperature side and the melting peak (endothermic peak) slope to the high-temperature side curve In the case where the temperature difference of the intersection of the tangent lines (melting end temperature) drawn at the point where the maximum value is 50 ° C or less and the shape of the curve does not show the stepped shape similarly shown in JIS K7121, it has crystallinity. I decided.

(Viscoelasticity measurement)
The viscoelasticity was measured using a rheometer (RDA 2RHIOS system ver. 4.3.2) manufactured by a rotating plate type rheometrics scientific F.E. The sample was set in a sample holder, and the temperature rising rate was 1 ° C./min, the frequency was 1 rad / s, the strain was 1% or less, and the detected torque was within the range of the guaranteed measurement value. If necessary, the sample holder was used separately for 8 mm and 20 mm. Storage elastic modulus G ′ against temperature change (
Pa) and loss elastic modulus G ″ (Pa) were obtained. The analysis was performed using software that is a standard of the viscoelasticity measuring apparatus.

[ Reference Example A]
(Production of resin latex)
40 parts of each of the polyester resins (A1 to A4, B1 to B7) shown in Tables 1 and 2 are added to 360 parts of ion exchange water, heated to 96 ° C., adjusted to pH = 9 with 5% ammonia water, 10 A polyester resin latex (A1Ltx to A4Ltx, B1Ltx to B7Ltx) was prepared using Ultra Turrax T-50 (manufactured by IKA) and stirring at 8000 rpm while adding 0.8 parts of a% dodecylbenzenesulfonic acid aqueous solution.

(Preparation of release agent dispersion A)
The following composition was mixed, heated to 97 ° C., and then dispersed with IKA Ultra Turrax T50. Thereafter, the dispersion was dispersed with a gorin homogenizer (manufactured by Matsuzaka Trading Co., Ltd.) and treated 20 times under the conditions of 105 ° C. and 550 kg / cm ² to obtain a release agent dispersion A having a center diameter of 190 nm.
・ Polywax (trade name: WEP-2 (manufactured by NOF Corporation) 100 parts) ・ Anionic surfactant Neogen SC (manufactured by Daiichi Kogyo Seiyaku) 5 parts ・ Ion exchange water 230 parts

(Preparation of blue pigment dispersion A)
The following composition was mixed and dissolved, and dispersed by homogenizer (IKA Ultra Tarrax) and ultrasonic irradiation to obtain a blue pigment dispersion A having a center particle size of 150 nm.
・ Sian pigment PB15: 3 (Copper phthalocyanine, Dainippon Ink & Chemicals) 50 parts ・ Anionic surfactant Neogen SC 5 parts ・ Ion-exchanged water 200 parts

(Preparation of core particle suspension (A1))
The following composition was mixed and dispersed with Ultra Turrax T50 in a round stainless steel flask, and then the contents in the flask were heated to 55 ° C. with stirring in an oil bath for heating and held at 55 ° C. for 1 hour.
-Crystalline polyester resin latex (A1Ltx) 1000 parts-Anionic surfactant Neogen SC 8 parts-Blue pigment dispersion A 25 parts-Release agent dispersion A 40 parts-10% by weight calcium chloride aqueous solution 10 parts

  Then, when the obtained content was observed with an optical microscope, it was confirmed that about 4.5 μm aggregated particles were generated. Further, the temperature of the heating oil bath was raised and held at 60 ° C. for 20 minutes. When the obtained contents were observed with an optical microscope, it was confirmed that aggregated particles of about 6.5 μm were formed. Adjust the pH to 8.0 with an aqueous sodium hydroxide solution, then raise the temperature of the heating oil bath to 75 ° C., cool, filter, wash thoroughly with ion-exchanged water, concentrate, and concentrate to a solid content of 40 % Core particle suspension (A1) was obtained. When the particle size of the core particles was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 6.8 μm.

(Preparation of core particle suspension (A2))
The following composition was mixed and dispersed with Ultra Turrax T50 in a round stainless steel flask, and then the contents in the flask were heated to 55 ° C. with stirring in an oil bath for heating and held at 55 ° C. for 1 hour.
-Crystalline polyester resin latex (A2Ltx) 500 parts-Amorphous polyester resin latex (B5Ltx) 500 parts-Anionic surfactant 8 parts-Pigment dispersion A 25 parts-Release agent dispersion A 40 parts-Calcium chloride 10 10 parts by weight aqueous solution

  Then, when the obtained content was observed with an optical microscope, it was confirmed that about 4.5 μm aggregated particles were generated. Further, the temperature of the heating oil bath was raised and held at 60 ° C. for 20 minutes. When the obtained contents were observed with an optical microscope, it was confirmed that aggregated particles of about 6.5 μm were formed. Adjust the pH to 8.0 with an aqueous sodium hydroxide solution, then raise the temperature of the heating oil bath to 75 ° C., cool, filter, wash thoroughly with ion-exchanged water, concentrate, and concentrate to a solid content of 40 % Core particle suspension (A2) was obtained. When the particle size of the core particles was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.0 μm.

(Preparation of core particle suspension (A3))
The following composition was mixed and dispersed with Ultra Turrax T50 in a round stainless steel flask, and then the contents in the flask were heated to 55 ° C. with stirring in an oil bath for heating and held at 55 ° C. for 1 hour.
・ Crystalline polyester resin latex (A3Ltx) 300 parts ・ Amorphous polyester resin latex (B6Ltx) 700 parts ・ Anionic surfactant 8 parts ・ Pigment dispersion A 25 parts ・ Releasing agent dispersion A 40 parts ・ Calcium chloride 10 10 parts by weight aqueous solution

  Then, when the obtained content was observed with an optical microscope, it was confirmed that about 4.5 μm aggregated particles were generated. Further, the temperature of the heating oil bath was raised and held at 60 ° C. for 20 minutes. When the obtained contents were observed with an optical microscope, it was confirmed that aggregated particles of about 6.5 μm were formed. Adjust the pH to 8.0 with an aqueous sodium hydroxide solution, then raise the temperature of the heating oil bath to 75 ° C., cool, filter, wash thoroughly with ion-exchanged water, concentrate, and concentrate to a solid content of 40 % Core particle suspension (A3) was obtained. When the particle size of the core particles was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.2 μm.

(Preparation of core particle suspension (A4))
The following composition was mixed and dispersed with Ultra Turrax T50 in a round stainless steel flask, and then the contents in the flask were heated to 55 ° C. with stirring in an oil bath for heating and held at 55 ° C. for 1 hour.
-Noncrystalline polyester resin latex (B4Ltx) 1000 parts-Anionic surfactant 8 parts-Pigment dispersion A 25 parts-Release agent dispersion A 40 parts-10% calcium chloride aqueous solution 10 parts

  Then, when the obtained content was observed with an optical microscope, it was confirmed that about 4.5 μm aggregated particles were generated. Further, the temperature of the heating oil bath was raised and held at 60 ° C. for 20 minutes. When the obtained contents were observed with an optical microscope, it was confirmed that aggregated particles of about 6.5 μm were formed. Adjust the pH to 8.0 with an aqueous sodium hydroxide solution, then raise the temperature of the heating oil bath to 75 ° C., cool, filter, wash thoroughly with ion-exchanged water, concentrate, and concentrate to a solid content of 40 % Core particle suspension (A4) was obtained. When the particle size of the core particles was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.2 μm.

(Preparation of core particle suspension (A5))
The following composition was mixed and dispersed with Ultra Turrax T50 in a round stainless steel flask, and then the contents in the flask were heated to 55 ° C. with stirring in an oil bath for heating and held at 55 ° C. for 1 hour.
-Crystalline polyester resin latex (B6Ltx) 1000 parts-Anionic surfactant 8 parts-Pigment dispersion A 25 parts-Release agent dispersion A 40 parts-10% by weight calcium chloride aqueous solution 10 parts

  Then, when the obtained content was observed with an optical microscope, it was confirmed that about 4.5 μm aggregated particles were generated. Further, the temperature of the heating oil bath was raised and held at 60 ° C. for 20 minutes. When the obtained contents were observed with an optical microscope, it was confirmed that aggregated particles of about 6.5 μm were formed. Adjust the pH to 8.0 with an aqueous sodium hydroxide solution, then raise the temperature of the heating oil bath to 75 ° C., cool, filter, wash thoroughly with ion-exchanged water, concentrate, and concentrate to a solid content of 40 % Core particle suspension (A5) was obtained. When the particle size of the core particles was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 6.9 μm.

(Preparation of core particle suspension (A6))
The following composition was mixed and dispersed with Ultra Turrax T50 in a round stainless steel flask, and then the contents in the flask were heated to 55 ° C. with stirring in an oil bath for heating and held at 55 ° C. for 1 hour.
・ Crystalline polyester resin latex (A4Ltx) 300 parts ・ Amorphous polyester resin latex (B4Ltx) 700 parts ・ Anionic surfactant 8 parts ・ Pigment dispersion A 25 parts ・ Releasing agent dispersion A 40 parts ・ Calcium chloride 10 10 parts by weight aqueous solution

  Then, when the obtained content was observed with an optical microscope, it was confirmed that about 4.5 μm aggregated particles were generated. Further, the temperature of the heating oil bath was raised and held at 60 ° C. for 20 minutes. When the obtained contents were observed with an optical microscope, it was confirmed that aggregated particles of about 6.5 μm were formed. Adjust the pH to 8.0 with an aqueous sodium hydroxide solution, then raise the temperature of the heating oil bath to 75 ° C., cool, filter, wash thoroughly with ion-exchanged water, concentrate, and concentrate to a solid content of 40 % Core particle suspension (A6) was obtained. When the particle size of the core particles was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.2 μm.

(Preparation of toner for electrophotography (A1))
To 125 parts of the core particle suspension (A1), 100 parts of an amorphous polyester resin latex (B1Ltx) is added with stirring, the pH is adjusted to 2.5, and 0.75 part of a 10% polyaluminum chloride aqueous solution is added dropwise. And stirring was continued for 30 minutes. The suspension was then warmed to 55 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (A1). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.0 μm.

  Around 100 parts of the above toner particles (A1), 1 part of metatitanic acid (volume average particle diameter 40 nm, i-butyltrimethoxysilane treatment) 1 part and silica (volume average particle diameter 140 nm, HMDS treatment, sol-gel method) 2 parts are surrounded by a Henschel mixer. After external additive blending was performed at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (A1).

(Preparation of toner for electrophotography (A2))
To 125 parts of the core particle suspension (A1), 100 parts of an amorphous polyester resin latex (B2Ltx) is added with stirring, the pH is adjusted to 2.5, and 0.75 part of a 10% polyaluminum chloride aqueous solution is added dropwise. And stirring was continued for 30 minutes. The suspension was then warmed to 55 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (A2). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.0 μm.

  Around 100 parts of the toner particles (A2), 1 part of metatitanic acid (volume average particle size 40 nm, i-butyltrimethoxysilane treatment) and 2 parts of silica (volume average particle size 140 nm, HMDS treatment, sol-gel method) were surrounded by a Henschel mixer. After external additive blending was performed at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (A2).

(Preparation of toner for electrophotography (A3))
To 125 parts of the core particle suspension (A1), 100 parts of an amorphous polyester resin latex (B3Ltx) is added with stirring, the pH is adjusted to 2.5, and 0.75 part of a 10% polyaluminum chloride aqueous solution is added dropwise. And stirring was continued for 30 minutes. The suspension was then warmed to 55 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (A3). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.4 μm.

  Around 100 parts of the above toner particles (A3), 1 part of metatitanic acid (volume average particle diameter 40 nm, i-butyltrimethoxysilane treatment) 1 part and silica (volume average particle diameter 140 nm, HMDS treatment, sol-gel method) 2 parts are surrounded by a Henschel mixer. After blending the external additive at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (A3).

(Preparation of electrophotographic toner (A4))
To 125 parts of the core particle suspension (A2), 100 parts of an amorphous polyester resin latex (B1Ltx) is added with stirring, the pH is adjusted to 2.5, and 0.75 part of a 10% polyaluminum chloride aqueous solution is added dropwise. And stirring was continued for 30 minutes. The suspension was then warmed to 55 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (A4). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.3 μm.

  Around 100 parts of the above toner particles (A4), 1 part of metatitanic acid (volume average particle diameter 40 nm, i-butyltrimethoxysilane treatment) and 2 parts of silica (volume average particle diameter 140 nm, HMDS treatment, sol-gel method) are surrounded by a Henschel mixer. After external additive blending was performed at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (A4).

(Preparation of toner for electrophotography (A5))
To 125 parts of the core particle suspension (A2), 100 parts of an amorphous polyester resin latex (B2Ltx) is added with stirring, the pH is adjusted to 2.5, and 0.75 part of a 10% polyaluminum chloride aqueous solution is added dropwise. And stirring was continued for 30 minutes. The suspension was then warmed to 55 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (A5). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.1 μm.

  Around 100 parts of the above toner particles (A5), 1 part of metatitanic acid (volume average particle size 40 nm, i-butyltrimethoxysilane treatment) and 2 parts of silica (volume average particle diameter 140 nm, HMDS treatment, sol-gel method) were cycled with a Henschel mixer. After external additive blending was performed at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (A5).

(Preparation of electrophotographic toner (A6))
To 125 parts of the core particle suspension (A2), 100 parts of an amorphous polyester resin latex (B3Ltx) is added with stirring, the pH is adjusted to 2.5, and 0.75 part of a 10% polyaluminum chloride aqueous solution is added dropwise. The stirring was continued for 30 minutes. The suspension was then warmed to 55 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (A6). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.3 μm.

Around 100 parts of the above toner particles (A6), 1 part of metatitanic acid (volume average particle diameter 40 nm, i-butyltrimethoxysilane treatment) 1 part and silica (volume average particle diameter 140 nm, HMDS treatment, sol-gel method) 2 parts are surrounded by a Henschel mixer. After external additive blending was performed at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (A6).

(Preparation of toner for electrophotography (A7))
While stirring, 125 parts of an amorphous polyester resin latex (B1Ltx) is added to 125 parts of the core particle suspension (A3), the pH is adjusted to 2.5, and 0.75 part of a 10% polyaluminum chloride aqueous solution is added dropwise. The stirring was continued for 30 minutes. The suspension was then warmed to 55 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (A7). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.5 μm.

  Around 100 parts of the above toner particles (A7), 1 part of metatitanic acid (volume average particle size 40 nm, i-butyltrimethoxysilane treatment) 1 part and silica (volume average particle diameter 140 nm, HMDS treatment, sol-gel method) 2 parts are surrounded by a Henschel mixer. After external additive blending was performed at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (A7).

(Preparation of toner for electrophotography (A8))
While stirring, 125 parts of an amorphous polyester resin latex (B2Ltx) is added to 125 parts of the core particle suspension (A3), the pH is adjusted to 2.5, and 0.75 part of a 10% polyaluminum chloride aqueous solution is added dropwise. The stirring was continued for 30 minutes. The suspension was then warmed to 55 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (A8). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.4 μm.

  Around 100 parts of the above toner particles (A8), 1 part of metatitanic acid (volume average particle size 40 nm, i-butyltrimethoxysilane treatment) and 2 parts of silica (volume average particle diameter 140 nm, HMDS treatment, sol-gel method) are surrounded by a Henschel mixer. After blending the external additive at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (A8).

(Preparation of toner for electrophotography (A9))
While stirring, 125 parts of an amorphous polyester resin latex (B3Ltx) is added to 125 parts of the core particle suspension (A3), the pH is adjusted to 2.5, and 0.75 part of a 10% polyaluminum chloride aqueous solution is added dropwise. The stirring was continued for 30 minutes. The suspension was then warmed to 55 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (A9). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.2 μm.

  Around 100 parts of the above toner particles (A9), 1 part of metatitanic acid (volume average particle size 40 nm, i-butyltrimethoxysilane treatment) and 2 parts of silica (volume average particle diameter 140 nm, HMDS treatment, sol-gel method) are surrounded by a Henschel mixer. After the external additive blending was performed at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (A9).

(Preparation of electrophotographic toner (A10))
While stirring, 125 parts of an amorphous polyester resin latex (B2Ltx) is added to 125 parts of the core particle suspension (A4), the pH is adjusted to 2.5, and 0.75 part of a 10% polyaluminum chloride aqueous solution is added dropwise. The stirring was continued for 30 minutes. The suspension was then warmed to 55 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (A10). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.2 μm.

  Around 100 parts of the above toner particles (A10), 1 part of metatitanic acid (volume average particle diameter 40 nm, i-butyltrimethoxysilane treatment) 1 part and silica (volume average particle diameter 140 nm, HMDS treatment, sol-gel method) 2 parts are surrounded by a Henschel mixer. After external additive blending was performed at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (A10).

(Preparation of toner for electrophotography (A11))
While stirring, 125 parts of a non-crystalline polyester resin latex (B5Ltx) is added to 125 parts of the core particle suspension (A5), the pH is adjusted to 2.5, and 0.75 part of a 10% polyaluminum chloride aqueous solution is added dropwise. The stirring was continued for 30 minutes. The suspension was then warmed to 55 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (A11). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.6 μm.

  Around 100 parts of the above toner particles (A11), 1 part of metatitanic acid (volume average particle size 40 nm, i-butyltrimethoxysilane treatment) and 2 parts of silica (volume average particle diameter 140 nm, HMDS treatment, sol-gel method) are surrounded by a Henschel mixer. After external additive blending was performed at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (A11).

(Preparation of electrophotographic toner (A12))
While stirring, 125 parts of an amorphous polyester resin latex (B6Ltx) is added to 125 parts of the core particle suspension (A4), the pH is adjusted to 2.5, and 0.75 part of a 10% polyaluminum chloride aqueous solution is added dropwise. The stirring was continued for 30 minutes. The suspension was then warmed to 55 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (A12). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.2 μm.

  Around 100 parts of the above toner particles (A12), 1 part of metatitanic acid (volume average particle diameter 40 nm, i-butyltrimethoxysilane treatment) and 2 parts of silica (volume average particle diameter 140 nm, HMDS treatment, sol-gel method) are surrounded by a Henschel mixer. After external additive blending was performed at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (A12).

(Preparation of toner for electrophotography (A13))
To 125 parts of the core particle suspension (A2), 100 parts of an amorphous polyester resin latex (B4Ltx) is added with stirring, the pH is adjusted to 2.5, and 0.75 part of a 10% polyaluminum chloride aqueous solution is added dropwise. The stirring was continued for 30 minutes. The suspension was then warmed to 52 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (A13). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.3 μm.

  Around 100 parts of the above toner particles (A13), 1 part of metatitanic acid (volume average particle size 40 nm, i-butyltrimethoxysilane treatment) and 2 parts of silica (volume average particle diameter 140 nm, HMDS treatment, sol-gel method) are surrounded by a Henschel mixer. After external additive blending was performed at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (A13).

(Preparation of electrophotographic toner (A14))
While stirring, 125 parts of an amorphous polyester resin latex (B6Ltx) is added to 125 parts of the core particle suspension (A2), the pH is adjusted to 2.5, and 0.75 part of a 10% polyaluminum chloride aqueous solution is added dropwise. The stirring was continued for 30 minutes. The suspension was then warmed to 55 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (A14). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.3 μm.

  Around 100 parts of the above toner particles (A14), 1 part of metatitanic acid (volume average particle size 40 nm, i-butyltrimethoxysilane treatment) 1 part and silica (volume average particle diameter 140 nm, HMDS treatment, sol-gel method) 2 parts are surrounded by a Henschel mixer. After blending external additives at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (A14).

(Preparation of electrophotographic toner (A15))
While stirring, 125 parts of an amorphous polyester resin latex (B5Ltx) is added to 125 parts of the core particle suspension (A3), the pH is adjusted to 2.5, and 0.75 part of a 10% polyaluminum chloride aqueous solution is added dropwise. The stirring was continued for 30 minutes. The suspension was then warmed to 55 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (A15). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.2 μm.

  Around 100 parts of the above toner particles (A15), 1 part of metatitanic acid (volume average particle size 40 nm, i-butyltrimethoxysilane treatment) and 2 parts of silica (volume average particle diameter 140 nm, HMDS treatment, sol-gel method) were surrounded by a Henschel mixer. After external additive blending was performed at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (A15).

(Preparation of electrophotographic toner (A16))
To 125 parts of the core particle suspension (A3), 100 parts of an amorphous polyester resin latex (B4Ltx) is added with stirring, the pH is adjusted to 2.5, and 0.75 part of a 10% polyaluminum chloride aqueous solution is added dropwise. And stirring was continued for 30 minutes. The suspension was then warmed to 52 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (A16). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.0 μm.

  Around 100 parts of the above toner particles (A16), 1 part of metatitanic acid (volume average particle size 40 nm, i-butyltrimethoxysilane treatment) and 2 parts of silica (volume average particle diameter 140 nm, HMDS treatment, sol-gel method) were surrounded by a Henschel mixer. After blending external additives at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (A16).

(Preparation of toner for electrophotography (A17))
To 125 parts of the core particle suspension (A6), 100 parts of an amorphous polyester resin latex (B6Ltx) is added with stirring, the pH is adjusted to 2.5, and 0.75 part of a 10% polyaluminum chloride aqueous solution is added dropwise. And stirring was continued for 30 minutes. The suspension was then warmed to 55 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (A17). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.0 μm.

  Around 100 parts of the above toner particles (A17), 1 part of metatitanic acid (volume average particle diameter 40 nm, i-butyltrimethoxysilane treatment) and 2 parts of silica (volume average particle diameter 140 nm, HMDS treatment, sol-gel method) are surrounded by a Henschel mixer. After external additive blending was performed at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (A17).

(Preparation of toner for electrophotography (A18))
While stirring, 125 parts of an amorphous polyester resin latex (B7Ltx) is added to 125 parts of the core particle suspension (A3), the pH is adjusted to 2.5, and 0.75 part of a 10% polyaluminum chloride aqueous solution is added dropwise. The stirring was continued for 30 minutes. The suspension was then warmed to 55 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (A18). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 5.9 μm.

  Around 100 parts of the above toner particles (A18), 1 part of metatitanic acid (volume average particle diameter of 40 nm, i-butyltrimethoxysilane treatment) and 2 parts of silica (volume average particle diameter of 140 nm, HMDS treatment, sol-gel method) were surrounded by a Henschel mixer. After external additive blending was performed at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (A18).

(Production of carrier (A1))
Carbon black (trade name: VXC-72, manufactured by Cabot) 0.12 part was mixed with 1.25 parts of toluene, and a trifunctional isocyanate 80 wt% ethyl acetate solution ( Takenate D110N (manufactured by Takeda Pharmaceutical Co., Ltd.) 1.25 parts of the coating agent resin solution and Mn—Mg—Sr ferrite particles (volume average particle size: 35 μm) were added to a kneader and mixed and stirred at room temperature for 5 minutes. Then, the temperature was raised to 150 ° C. at normal pressure to distill off the solvent. After further 30 minutes of mixing and stirring, the heater was turned off and the temperature was lowered to 50 ° C. The obtained coated carrier was sieved with a 75 μm mesh to prepare a carrier.

(Production of electrophotographic developers (A1) to (A18))
5 parts of each of the electrophotographic toners (A1) to (A18) and 95 parts of the carrier (A1) are placed in a V blender and stirred for 20 minutes, and then sieved with a 105 μm mesh to obtain electrophotographic developers (A1) to (A18). ) Was produced.

( Reference Examples A1 to A11)
Using the electrophotographic toners (A1) to (A10) and A18 and the electrophotographic developers (A1) to (A10) and A18, evaluation of the minimum fixing temperature, evaluation of storage stability, stability in the developing device Evaluation, density maintenance, and background fogging were evaluated.

(Comparative Examples A1 to A7)
Using the electrophotographic toners (A11) to (A17) and the electrophotographic developers (A11) to (A17), the evaluation of the minimum fixing temperature, the evaluation of storage stability, the evaluation of the stability in the developing unit, and the concentration maintenance Evaluation of the nature and background fogging was performed.

(Evaluation)
-Evaluation of minimum fixing temperature-
The obtained electrophotographic toners (A1) to (A18) were formed on a copy paper (J paper) manufactured by Fuji Xerox so as to have a toner amount of 1.3 mg / cm ^2. The image was fixed using a fixing device modified so that the temperature of the fixing device (manufactured by Xerox Co., Ltd.) could be freely controlled, and the low-temperature fixing property was evaluated. In the evaluation, the fixing device temperature was changed from 80 ° C. to 150 ° C. at every 10 ° C., and a fixed image was prepared at each fixing temperature. The degree of peeling of the image was observed, and the width of the paper that appeared at the crease as a result of peeling the image was measured. The fixing temperature at which the width was 0.5 mm or less was defined as MFT (minimum fixing temperature, ° C.).

-Evaluation of storage stability-
400 g of the obtained electrophotographic toners (A1) to (A18) are filled in a toner cartridge of the Docu Center Color 500, stored in an environment of 55 ° C. for 72 hours, and then loaded into the Docu Center Color 500, continuously 500 sheets. The image was evaluated and image defects were evaluated.

-Stability evaluation in the developer-
400 g of the obtained electrophotographic developer (A1) to (A18) is charged into the development unit of the document center color 500, and the device is modified so that only the development unit can be driven independently, in an environment of 30 ° C./85% RH. Then, after driving for 120 minutes, it was loaded into the docu center collar 500, image evaluation of 500 continuous images was performed, and image defects were evaluated.

-Evaluation of density maintenance and background fogging-
Using the obtained electrophotographic developers (A1) to (A18), 100000 sheets were printed with the Docu Center Color 500, and image density maintenance (average density up to the 1st to 10th sheets and 99991th sheet) The difference in the average density of the 100,000th sheet) and the fogging of the background portion were evaluated. The density measurement was performed using a Macbeth densitometer, and the background fog was visually evaluated from the following viewpoints.
○: No visual problem △: There is some fogging on the background, but acceptable for practical use ×: The background is stained blue, practically unacceptable

Various physical properties are shown in Table 3 together with the evaluation results of the reference examples and comparative examples.

  From these results, when the toner of the present invention is used, it has excellent low-temperature fixability, excellent blocking resistance during storage, excellent blocking resistance against stress in the image forming apparatus, maintains the image density, and covers the background portion. It can be seen that a uniform image can be obtained stably.

[Example B]
(Synthesis of crystalline polyester resin (B'1))
In a heat-dried 5 L flask, 1933 parts (9.57 mol) of sebacic acid, 1180 parts (10 mol) of 1,6-hexanediol, 118.4 parts (0.4 mol) of sodium dimethyl-5-sulfonate, 2 mol, 2 , 6-Naphthalenedicarboxylic acid 6.48 parts (0.03 mol) was added, the air in the container was depressurized by depressurization, and the mixture was refluxed at 180 ° C. for 6 hours under an inert atmosphere with nitrogen gas. Subsequently, the temperature was gradually raised to 220 ° C. under reduced pressure and stirred for 4 hours. When the mixture became viscous, the molecular weight was confirmed by GPC, and when the weight average molecular weight reached 22000, the distillation under reduced pressure was stopped. Air-cooled to obtain a crystalline polyester resin (B′1). The obtained resin had a melting point (DSC peak top) of 69 ° C.

(Preparation of crystalline polyester resin dispersion (B′1))
The obtained crystalline polyester resin (B′1) was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) at a rate of 100 g / min. In a separately prepared aqueous medium tank, 5% by weight diluted ammonia water obtained by diluting reagent ammonia water with ion-exchanged water is added, pH is adjusted to 8.4, and then heated to 120 ° C. with a heat exchanger. The polyester resin melt was transferred to the Cavitron at a speed of 0.1 liter per minute. In this state, the Cavitron was operated under the conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm ² , and a crystalline polyester resin dispersion (B′1) having a volume average particle size of 0.20 μm (resin particle concentration : 20% by weight).

(Synthesis of crystalline polyester resin (B'2))
Crystalline polyester resin (B'1) except that in the preparation of crystalline polyester (B'1) resin, 1757 parts (8.7 mol) of sebacic acid and 189 parts (0.9 mol) of 2,6-naphthalenedicarboxylic acid were used. A crystalline polyester resin (B′2) was obtained in the same manner as in the above synthesis. The air in the container was depressurized by a depressurization operation, and further an inert atmosphere was established with nitrogen gas, followed by stirring at 200 ° C. for 2 hours. Subsequently, the temperature was raised to 220 ° C. under reduced pressure, stirring was continued for 10 minutes, distillation under reduced pressure was stopped, and air cooling was performed to obtain a crystalline polyester resin (B′2). Further, the melting point (DSC peak top) of the obtained resin was 67 ° C.

(Preparation of crystalline polyester resin dispersion (B′2))
The obtained crystalline polyester resin (B′2) was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) at a rate of 100 g / min. A separately prepared aqueous medium tank is filled with 5% by weight diluted ammonia water diluted with ion-exchanged water with reagent ammonia water, adjusted to pH 8.2, and heated to 120 ° C with a heat exchanger every minute. At the rate of 0.1 liter, it was transferred to the Cavitron at the same time as the polyester resin melt. In this state, the Cavitron was operated under the conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm ² , and a crystalline polyester resin dispersion (B′2) (resin particle concentration with a volume average particle size of 0.19 μm). : 20% by weight).

(Synthesis of crystalline polyester resin (B'3))
The preparation of the crystalline polyester resin (B′1) was the same as the synthesis of the crystalline polyester resin 1 except that 1535 parts (7.6 mol) of sebacic acid and 420 parts (2.0 mol) of 2,6-naphthalenedicarboxylic acid were used. To obtain a crystalline polyester resin (3). The obtained resin had a melting point (DSC peak top) of 64 ° C.

(Preparation of crystalline polyester resin dispersion (B'3))
The obtained crystalline polyester resin (B′3) was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) at a rate of 100 g / min. A separately prepared aqueous medium tank is filled with 5% by weight diluted ammonia water obtained by diluting reagent ammonia water with ion exchange water, adjusted to pH 8.0, and heated to 120 ° C. with a heat exchanger every minute. At the rate of 0.1 liter, it was transferred to the Cavitron at the same time as the polyester resin melt. In this state, the Cavitron was operated under conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm ² , and a crystalline polyester resin dispersion (B′3) having a volume average particle size of 0.21 μm (resin particle concentration : 20% by weight).

(Preparation of release agent dispersion B)
-Paraffin wax (Nippon Seiwa Co., Ltd .: HNP9, melting point 77 ° C): 50 parts-Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK): 5 parts-Ion-exchanged water: 200 parts The components were heated to 110 ° C. and dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then dispersed by a Manton Gorin high-pressure homogenizer (Gorin), and the volume average particle size was 0.23 μm. A release agent dispersion B (release agent concentration: 20% by weight) prepared by dispersing the release agent was prepared.

(Preparation of colorant dispersion B)
-Cyan pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Blue 15: 3 (copper phthalocyanine)): 1000 parts-Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen R): 150 parts-Ion-exchanged water: 9000 Part Colorant dispersion B obtained by mixing and dissolving the above components and dispersing the colorant (cyan pigment) by dispersing for about 1 hour using a high-pressure impact disperser Ultimateizer (manufactured by Sugino Machine Co., Ltd., HJP30006) Was prepared. The colorant dispersion B (colorant particle concentration: 23% by weight) having a volume average particle diameter of the colorant (cyan pigment) in the colorant dispersion B of 0.16 μm was obtained.

<Manufacture of core particle suspension (B1)>
The following composition was mixed and dispersed with Ultra Turrax T50 in a round stainless steel flask, and then the contents in the flask were heated to 55 ° C. with stirring in an oil bath for heating and held at 55 ° C. for 1 hour.
-Crystalline polyester resin dispersion (B'2) 1000 parts-Anionic surfactant 8 parts-Colorant dispersion B 25 parts-Release agent dispersion B 40 parts-10% calcium chloride aqueous solution 10 parts-Tributyl titanium 0.66 parts of oxide

  Then, when the obtained content was observed with an optical microscope, it was confirmed that about 4.5 μm aggregated particles were generated. Further, the temperature of the heating oil bath was raised and held at 60 ° C. for 20 minutes. When the obtained contents were observed with an optical microscope, it was confirmed that aggregated particles of about 6.5 μm were formed. Adjust the pH to 8.0 with an aqueous sodium hydroxide solution, then raise the temperature of the heating oil bath to 75 ° C., cool, filter, wash thoroughly with ion-exchanged water, concentrate, and concentrate to a solid content of 40 % Core particle suspension (B1) was obtained. When the particle size of the core particles was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 6.8 μm.

<Manufacture of core particle suspension (B2)>
In the production of the core particle suspension (B1), a core particle suspension (B2) was obtained by operating in the same manner as in the production of the core particle suspension (B1) except that tributyltitanium oxide was changed to 32 parts. . The volume average particle diameter of the obtained core particles was 6.3 μm.

<Manufacture of core particle suspension (B3)>
In the production of the core particle suspension (B1), a core particle suspension (B3) was obtained in the same manner as in the production of the core particle suspension (B1) except that tributyltitanium oxide was changed to tributyltin oxide. . The obtained core particles had a volume average particle size of 7.0 μm.

<Manufacture of core particle suspension (B4)>
In the production of the core particle suspension (B2), a core particle suspension (B4) was obtained in the same manner as in the production of the core particle suspension (B1) except that tributyltitanium oxide was changed to tributyltin oxide. . The obtained core particles had a volume average particle size of 6.9 μm.

<Manufacture of core particle suspension (B5)>
In the production of the core particle suspension (B1), the core particle suspension (B5) was obtained by operating in the same manner as the production of the core particle suspension (B1) except that tributyltitanium oxide was changed to tributylgermanium oxide. It was. The volume average particle diameter of the obtained core particles was 6.8 μm.

<Manufacture of core particle suspension (B6)>
In the production of the core particle suspension (B2), a core particle suspension ( B6 ) was obtained in the same manner as in the production of the core particle suspension (B1) except that tributyltitanium oxide was changed to tributylgermanium. The obtained core particles had a volume average particle size of 6.5 μm.

<Manufacture of core particle suspension (B7)>
In the production of the core particle suspension (B1), the production of the core particle suspension (B1) was changed except that the crystalline polyester resin was changed to (B′1) and tributyltitanium oxide was changed to 16.3 parts. The same operation was performed to obtain a core particle suspension (B7). The volume average particle diameter of the obtained core particles was 6.8 μm.

<Manufacture of core particle suspension (B8)>
In the production of the core particle suspension (B1), the core particle suspension ( B8 ) was prepared in the same manner as in the production of the core particle suspension (B1) except that tributyltitanium oxide was changed to 0.32 parts. Obtained. The obtained core particles had a volume average particle size of 6.6 μm.

<Manufacture of core particle suspension (B9)>
In the production of the core particle suspension (B1), a core particle suspension (B9) was obtained in the same manner as in the production of the core particle suspension (B1) except that tributyltitanium oxide was changed to 39 parts. . The volume average particle diameter of the obtained core particles was 7.1 μm.

<Manufacture of core particle suspension (B10)>
In the production of the core particle suspension (B1), the production of the core particle suspension (B1) was changed except that the crystalline polyester resin was changed to (B′3) and tributyltitanium oxide was changed to 16.4 parts. The same operation was performed to obtain a core particle suspension (B10). The obtained core particles had a volume average particle size of 6.5 μm.

(Preparation of toner for electrophotography (B1))
While stirring, 125 parts of an amorphous polyester resin latex (B2Ltx: see Reference Example A) is added to 125 parts of the core particle suspension (B1), the pH is adjusted to 2.5, and a polyaluminum chloride 10% aqueous solution 0 is added. .75 parts was added dropwise and stirring was continued for 30 minutes. The suspension was then warmed to 55 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (B1). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.0 μm.

  Around 100 parts of the above toner particles (B1), 1 part of metatitanic acid (volume average particle diameter 40 nm, i-butyltrimethoxysilane treatment) 1 part and silica (volume average particle diameter 140 nm, HMDS treatment, sol-gel method) 2 parts are surrounded by a Henschel mixer. After external additive blending was performed at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (B1).

(Preparation of toners for electrophotography (B2) to (B10))
The production of the electrophotographic toner (B1) was carried out in the same manner as the production of the electrophotographic toner (B1) except that the core particle suspension was changed to (B2) to (B10), respectively. B2) to (B10) were prepared.

(Preparation of developers (B1) to (B10))
50 parts of each of the electrophotographic toners (B1) to (B10) was weighed, and 1.8 parts of hydrophobic silica (Cabot, TS 720) was added and mixed in a sample mill. The externally added toner was weighed so that the toner concentration was 5% by weight with respect to a ferrite carrier having a volume average particle diameter of 50 μm coated with 1% by weight of methacrylate (manufactured by Soken Chemical Co., Ltd.), and stirred for 5 minutes with a ball mill. By mixing, developers (B1) to (B10) were obtained.

(Example B1)
The toner (1) (developer (B1)) is maintained at PS: 160 mm / s using a DocuCentre Color 400 modified machine manufactured by Fuji Xerox Co., and the temperature is changed between 60 ° C. and 200 ° C. every 10 ° C. As a result of fixing and evaluating while raising, it was excellent in writing resistance with a ballpoint pen, and no crack was observed in the fixed image.

(Example B2)
The toner (B2) (developer (B2)) is maintained at PS: 160 mm / s using a DocuCentre Color 400 remodeling machine manufactured by Fuji Xerox Co., and the temperature is changed between 60 ° C. and 200 ° C. every 10 ° C. As a result of fixing and evaluating while raising, it was excellent in writing resistance with a ballpoint pen, and no crack was observed in the fixed image.

(Example B3)
The toner (B3) (developer (B3)) is maintained at PS: 160 mm / s using a DocuCentre Color 400 remodeling machine manufactured by Fuji Xerox Co., and the temperature is changed between 60 ° C. and 200 ° C. every 10 ° C. As a result of fixing and evaluating while raising, it was excellent in writing resistance with a ballpoint pen, and no crack was observed in the fixed image.

(Example B4)
The toner (B4) (developer (B4)) is maintained at PS: 160 mm / s using a DocuCentre Color 400 remodeling machine manufactured by Fuji Xerox Co., Ltd., and the temperature is set between 60 ° C. and 200 ° C. every 10 ° C. As a result of fixing and evaluating while raising, it was excellent in writing resistance with a ballpoint pen, and no crack was observed in the fixed image.

(Example B5)
The toner (B5) (developer (B6)) is maintained at PS: 160 mm / s using a DocuCentre Color 400 modified machine manufactured by Fuji Xerox Co., Ltd., and the temperature is changed between 60 ° C. and 200 ° C. every 10 ° C. As a result of fixing and evaluating while raising, it was excellent in writing resistance with a ballpoint pen, and no crack was observed in the fixed image.

(Example B6)
The toner (B6) (developer (B6)) is held at PS: 160 mm / s using a DocuCentre Color 400 remodeling machine manufactured by Fuji Xerox Co., and the temperature is changed between 60 ° C. and 200 ° C. every 10 ° C. As a result of fixing and evaluating while raising, it was excellent in writing resistance with a ballpoint pen, and no crack was observed in the fixed image.

( Reference Example B7)
The toner (B7) (developer (B7)) is maintained at PS: 160 mm / s using a DocuCentre Color 400 remodeling machine manufactured by Fuji Xerox Co., and the temperature is changed between 60 ° C. and 200 ° C. every 10 ° C. When the image was fixed and evaluated while being raised, a remarkable image defect was caused by writing with a ballpoint pen. In addition, the occurrence of cracks was observed in the fixed image.

( Reference Example B8)
The toner (B8) (developer (B8)) is maintained at PS: 160 mm / s using a DocuCentre Color 400 remodeled machine manufactured by Fuji Xerox Co., and the temperature is changed between 60 ° C. and 200 ° C. every 10 ° C. As a result of fixing and evaluating while raising, the low-temperature fixability of the obtained toner image was evaluated. As a result, it was confirmed that the toner image was excellent in low-temperature fixability. However, slight image defects were observed for writing with a ballpoint pen. In addition, cracks were observed in the fixed image.

( Reference Example B9)
The toner (B9) (developer (B9)) is maintained at PS: 160 mm / s using a modified DocuCentre Color 400 manufactured by Fuji Xerox Co., Ltd., and the temperature is set between 60 ° C. and 200 ° C. every 10 ° C. When the image was fixed and evaluated while being raised, a remarkable image defect was caused by writing with a ballpoint pen. In addition, cracks were observed in the fixed image.

( Reference Example B10)
The toner (B10) (developer (B10)) is maintained at PS: 160 mm / s using a DocuCentre Color 400 modified machine manufactured by Fuji Xerox Co., Ltd., and the temperature is changed between 60 ° C. and 200 ° C. every 10 ° C. When the image was fixed and evaluated while being raised, an image defect occurred with respect to writing with a ballpoint pen. Further, cracks were observed in the fixed image.

[Evaluation methods and standards]
(Writing resistance)
The fixed image was written with a ballpoint pen, the writing resistance level was visually confirmed, and judged according to the following criteria. For the paper, the product name “Mirror Coat Platinum” manufactured by Fuji Xerox Office Supply Co., Ltd. was used.
○: Image defect does not occur when writing with a ballpoint pen.
(Triangle | delta): The slight image defect is recognized with respect to writing of a ball-point pen.
X: Significant image defects occur with respect to writing with a ballpoint pen.

(Crack level)
The crack level was visually confirmed and judged according to the following criteria. For the paper, the product name “Mirror Coat Platinum” manufactured by Fuji Xerox Office Supply Co., Ltd. was used.
○: Cracks do not occur even during long-term storage.
X: Cracks occur immediately after fixing or after storage for several weeks.

The results of Examples B1 to B6 and Reference Examples B7 to B10 are shown in Tables 4 to 5.

These results, as the constituent material of the core particle, by a polymerization unit having a naphthalene skeleton and having a predetermined amount, and applying the alkyl titanium, sintered-crystalline polyester resin you contain at least one alkyl tin and alkyl germanium, In addition to realizing low-temperature fixing, particularly when fixed to coated paper or cardboard, it can be seen that the image strength is excellent with respect to writing resistance, and cracks are not generated in the image even during long-term storage.

[Example C]
(Synthesis of crystalline polyester resin (C1))
In a heat-dried 5 L flask, 1933 parts (9.57 mol) of sebacic acid, 1180 parts (10 mol) of 1,6-hexanediol, 118.4 parts (0.4 mol) of sodium dimethyl-5-sulfonate, biphenyl, biphenyl 6.48 parts (0.027 mol) of -4,4'-dicarboxylic acid was added, the air in the container was depressurized by a depressurization operation, and the mixture was refluxed at 180 ° C. for 6 hours under an inert atmosphere with nitrogen gas. . Subsequently, the temperature was gradually raised to 220 ° C. under reduced pressure and stirred for 4 hours. When the mixture became viscous, the molecular weight was confirmed by GPC, and when the weight average molecular weight reached 22000, the distillation under reduced pressure was stopped. Air-cooled to obtain a crystalline polyester resin (C1). The obtained resin had a melting point (DSC peak top) of 69 ° C.

(Preparation of crystalline polyester resin dispersion (C1))
The obtained crystalline polyester resin (C1) was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) at a rate of 100 g / min. In a separately prepared aqueous medium tank, 5% by weight diluted ammonia water obtained by diluting reagent ammonia water with ion-exchanged water is added, pH is adjusted to 8.4, and then heated to 120 ° C. with a heat exchanger. The polyester resin melt was transferred to the Cavitron at a speed of 0.1 liter per minute. In this state, the Cavitron was operated under the conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm ² , and a crystalline polyester resin dispersion (C1) having a volume average particle size of 0.20 μm (resin particle concentration: 20 % By weight).

(Synthesis of crystalline polyester resin (C2))
Crystalline polyester resin (C1) except that in the preparation of the crystalline polyester (C1) resin, 1757 parts (8.7 mol) of sebacic acid and 194.4 parts (0.8 mol) of biphenyl-4,4′-dicarboxylic acid were used. A crystalline polyester resin (C2) was obtained in the same manner as in the above synthesis. The air in the container was depressurized by a depressurization operation, and further an inert atmosphere was established with nitrogen gas, followed by stirring at 200 ° C. for 2 hours. Subsequently, the temperature was raised to 220 ° C. under reduced pressure, and the mixture was stirred for 10 minutes to stop distillation under reduced pressure, and then air-cooled to obtain a crystalline polyester resin (C2). Further, the melting point (DSC peak top) of the obtained resin was 67 ° C.

(Preparation of crystalline polyester resin dispersion (C2))
The obtained crystalline polyester resin (C2) was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) at a rate of 100 g / min. A separately prepared aqueous medium tank is filled with 5% by weight diluted ammonia water diluted with ion-exchanged water with reagent ammonia water, adjusted to pH 8.2, and heated to 120 ° C with a heat exchanger every minute. At the rate of 0.1 liter, it was transferred to the Cavitron at the same time as the polyester resin melt. In this state, the Cavitron was operated under the conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm ² , and a crystalline polyester resin dispersion (C2) having a volume average particle size of 0.19 μm (resin particle concentration: 20 % By weight).

(Synthesis of crystalline polyester resin (C3))
Synthesis of the crystalline polyester resin (C1) except that in the preparation of the crystalline polyester (C1) resin, 1535 parts (7.6 mol) of sebacic acid and 432 parts (1.79 mol) of biphenyl-4,4′-dicarboxylic acid were used. In the same manner as above, a crystalline polyester resin (C3) was obtained. The obtained resin had a melting point (DSC peak top) of 64 ° C.

(Preparation of crystalline polyester resin dispersion (C3))
The obtained crystalline polyester resin (C3) was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) at a rate of 100 g / min. A separately prepared aqueous medium tank is filled with 5% by weight diluted ammonia water obtained by diluting reagent ammonia water with ion exchange water, adjusted to pH 8.0, and heated to 120 ° C. with a heat exchanger every minute. At the rate of 0.1 liter, it was transferred to the Cavitron at the same time as the polyester resin melt. In this state, the Cavitron was operated under the conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm ² , and a crystalline polyester resin dispersion (C3) having a volume average particle size of 0.21 μm (resin particle concentration: 20 % By weight).

<Preparation of release agent dispersion C>
-Paraffin wax (Nippon Seiwa Co., Ltd .: HNP9, melting point 77 ° C): 50 parts-Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK): 5 parts-Ion-exchanged water: 200 parts The components were heated to 110 ° C. and dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then dispersed with a Menton Gorin high-pressure homogenizer (Gorin), and the volume average particle size was 0.23 μm. A release agent dispersion C (release agent concentration: 20% by weight) prepared by dispersing the release agent was prepared.

<Preparation of Colorant Dispersion C>
Cyan pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Blue 15: 3 (copper phthalocyanine)): 1000 partsAnionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen R): 150 parts Ion-exchanged water: 9000 parts A colorant dispersion C obtained by mixing and dissolving the above components and dispersing the colorant (cyan pigment) by dispersing for about 1 hour using a high-pressure impact disperser Ultimateizer (manufactured by Sugino Machine Co., Ltd., HJP30006). Prepared. A colorant dispersion (colorant particle concentration: 23% by weight) having a volume average particle diameter of the colorant (cyan pigment) in the colorant dispersion C of 0.16 μm was obtained.

<Manufacture of core particle suspension (1)>
After mixing and dispersing the following composition in a round stainless steel flask with Ultra Turrax T50, the contents in the flask were heated to 55 ° C. with stirring in an oil bath for heating and held at 55 ° C. for 1 hour.
-Crystalline polyester resin dispersion (C2) 1000 parts-Anionic surfactant 8 parts-Colorant dispersion C 25 parts-Release agent dispersion C 40 parts-10% calcium chloride aqueous solution 10 parts-Tributyltitanium oxide 0 .66 parts

  Then, when the obtained content was observed with an optical microscope, it was confirmed that about 4.5 μm aggregated particles were generated. Further, the temperature of the heating oil bath was raised and held at 60 ° C. for 20 minutes. When the obtained contents were observed with an optical microscope, it was confirmed that aggregated particles of about 6.5 μm were formed. Adjust the pH to 8.0 with an aqueous sodium hydroxide solution, then raise the temperature of the heating oil bath to 75 ° C., cool, filter, wash thoroughly with ion-exchanged water, concentrate, and concentrate to a solid content of 40 % Core particle suspension (C1) was obtained. When the particle size of the core particles was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 6.8 μm.

<Manufacture of core particle suspension (C2)>
In the production of the core particle suspension (C1), a core particle suspension (C2) was obtained in the same manner as in the production of the core particle suspension (C1) except that tributyltitanium oxide was changed to 32 parts. . The volume average particle diameter of the obtained core particles was 6.3 μm.

<Manufacture of core particle suspension (C3)>
In the production of the core particle suspension (C1), a core particle suspension (C3) was obtained in the same manner as in the production of the core particle suspension (C1) except that tributyltitanium oxide was changed to tributyltin oxide. . The volume average particle diameter of the obtained core particles was 7.0 μm.

<Manufacture of core particle suspension (C4)>
In the production of the core particle suspension (C2), a core particle suspension (C4) was obtained in the same manner as in the production of the core particle suspension (C1) except that tributyltitanium oxide was changed to tributyltin oxide. . The obtained core particles had a volume average particle size of 6.9 μm.

<Manufacture of core particle suspension (C5)>
In the production of the core particle suspension (C1), the core particle suspension (C5) was obtained by operating in the same manner as the production of the core particle suspension (C1) except that tributyltitanium oxide was changed to tributylgermanium oxide. It was. The volume average particle diameter of the obtained core particles was 6.8 μm.

<Manufacture of core particle suspension (C6)>
In the production of the core particle suspension (C2), a core particle suspension ( C6 ) was obtained in the same manner as in the production of the core particle suspension (C1) except that tributyltitanium oxide was changed to tributylgermanium. The obtained core particles had a volume average particle size of 6.5 μm.

<Manufacture of core particle suspension (C7)>
In the production of the core particle suspension (C1), the crystalline polyester resin was changed to (C1) and the tributyltitanium oxide was changed to 16.3 parts as in the production of the core particle suspension (C1). Operation was performed to obtain a core particle suspension (C7). The volume average particle diameter of the obtained core particles was 6.8 μm.

<Manufacture of core particle suspension (C8)>
In the production of the core particle suspension (C1), the core particle suspension ( C8 ) was prepared in the same manner as in the production of the core particle suspension (C1) except that tributyltitanium oxide was changed to 0.32 parts. Obtained. The obtained core particles had a volume average particle size of 6.6 μm.

<Manufacture of core particle suspension (C9)>
In the production of the core particle suspension (C1), a core particle suspension (C9) was obtained in the same manner as in the production of the core particle suspension (C1) except that tributyltitanium oxide was changed to 39 parts. . The volume average particle diameter of the obtained core particles was 7.1 μm.

<Manufacture of core particle suspension (C10)>
In the production of the core particle suspension (C1), the crystalline polyester resin was changed to (C3) and the tributyltitanium oxide was changed to 16.4 parts, as in the production of the core particle suspension (C1). Operation was performed to obtain a core particle suspension (C10). The obtained core particles had a volume average particle size of 6.5 μm.

(Preparation of toner for electrophotography (C1))
While stirring, 125 parts of a non-crystalline polyester resin latex (B2Ltx: see Reference Example A) is added to 125 parts of the core particle suspension (C1), the pH is adjusted to 2.5, and a polyaluminum chloride 10% aqueous solution 0 is added. .75 parts was added dropwise and stirring was continued for 30 minutes. The suspension was then warmed to 55 ° C. and stirred for an additional 3 hours. The obtained toner particles were filtered, and the wet cake was dried using a freeze dryer to obtain toner particles (C1). When the particle size of the toner was measured with a Coulter counter, the 50% D diameter of the volume average particle diameter was 7.0 μm.

  Around 100 parts of the above toner particles (C1), 1 part of metatitanic acid (volume average particle diameter 40 nm, i-butyltrimethoxysilane treatment) 1 part and silica (volume average particle diameter 140 nm, HMDS treatment, sol-gel method) 2 parts are surrounded by a Henschel mixer. After external additive blending was performed at a speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm to obtain an electrophotographic toner (C1).

(Preparation of toners for electrophotography (C2) to (C10))
In the production of the electrophotographic toner (C1), the electrophotographic toner (C1) was operated in the same manner as in the production of the electrophotographic toner (C1) except that the core particle suspension was healthy (C2) to (C10). C2) to (C10) were prepared.

(Preparation of developers (C1) to (C10))
50 parts of each of the electrophotographic toners (C1) to (C10) was weighed, 1.8 parts of hydrophobic silica (manufactured by Cabot, TS 720) was added and mixed in a sample mill. The externally added toner was weighed so that the toner concentration was 5% by weight with respect to a ferrite carrier having a volume average particle diameter of 50 μm coated with 1% by weight of methacrylate (manufactured by Soken Chemical Co., Ltd.), and stirred for 5 minutes with a ball mill. By mixing, developers (C1) to (C10) were obtained.

(Example C1)
The toner (C1) (developer (C)) is held at PS: 160 mm / s using a DocuCentre Color 400 remodeled machine manufactured by Fuji Xerox Co., and the temperature is changed between 60 ° C. and 200 ° C. every 10 ° C. As a result of fixing and evaluating while raising, it was excellent in writing resistance with a ballpoint pen, and no crack was observed in the fixed image.

(Example C2)
The toner (C2) (developer (C2)) is maintained at PS: 160 mm / s using a DocuCentre Color 400 remodeling machine manufactured by Fuji Xerox Co., and the temperature is set between 60 ° C. and 200 ° C. every 10 ° C. As a result of fixing and evaluating while raising, it was excellent in writing resistance with a ballpoint pen, and no crack was observed in the fixed image.

(Example C3)
The toner (C3) (developer (C3)) is maintained at PS: 160 mm / s using a DocuCentre Color 400 modified machine manufactured by Fuji Xerox Co., and the temperature is changed between 60 ° C. and 200 ° C. every 10 ° C. As a result of fixing and evaluating while raising, it was excellent in writing resistance with a ballpoint pen, and no cracks were observed in the fixed image.

(Example C4)
The toner (C4) (developer (C4)) is maintained at PS: 160 mm / s using a modified DocuCenter Color 400 manufactured by Fuji Xerox Co., Ltd., and the temperature is changed between 60 ° C. and 200 ° C. every 10 ° C. As a result of fixing and evaluating while raising, it was excellent in writing resistance with a ballpoint pen, and no crack was observed in the fixed image.

(Example C5)
The toner (C5) (developer (C5)) is maintained at PS: 160 mm / s using a modified DocuCenter Color 400 manufactured by Fuji Xerox Co., Ltd., and the temperature is changed between 60 ° C. and 200 ° C. every 10 ° C. As a result of fixing and evaluating while raising, it was excellent in writing resistance with a ballpoint pen, and no crack was observed in the fixed image.

(Example C6)
The toner (C6) (developer (C6)) is maintained at PS: 160 mm / s using a modified DocuCentre Color 400 manufactured by Fuji Xerox Co., Ltd., and the temperature is set between 60 ° C. and 200 ° C. every 10 ° C. As a result of fixing and evaluating while raising, it was excellent in writing resistance with a ballpoint pen, and no crack was observed in the fixed image.

( Reference Example C7)
The toner (C7) (developer (C7)) is maintained at PS: 160 mm / s using a modified DocuCentre Color 400 manufactured by Fuji Xerox Co., Ltd., and the temperature is changed between 10 ° C. and 60 ° C. every 10 ° C. When the image was fixed and evaluated while being raised, a remarkable image defect was caused by writing with a ballpoint pen. In addition, the occurrence of cracks was observed in the fixed image.

( Reference Example C8)
The toner (C8) (developer (C8)) is maintained at PS: 160 mm / s using a modified DocuCentre Color 400 manufactured by Fuji Xerox Co., Ltd., and the temperature is set between 60 ° C. and 200 ° C. every 10 ° C. As a result of fixing and evaluating while raising, the low-temperature fixability of the obtained toner image was evaluated. As a result, it was confirmed that the toner image was excellent in low-temperature fixability. However, slight image defects were observed for writing with a ballpoint pen. In addition, cracks were observed in the fixed image.

( Reference Example C9)
The toner (C9) (developer (C9)) is maintained at PS: 160 mm / s using a modified DocuCentre Color 400 manufactured by Fuji Xerox Co., Ltd., and the temperature is kept between 60 ° C. and 200 ° C. every 10 ° C. When the image was fixed and evaluated while being raised, a remarkable image defect was caused by writing with a ballpoint pen. In addition, cracks were observed in the fixed image.

( Reference Example C10)
The toner (C10) (developer (C10)) is held at PS: 160 mm / s using a DocuCentre Color 400 remodeling machine manufactured by Fuji Xerox Co., and the temperature is changed between 60 ° C. and 200 ° C. every 10 ° C. When the image was fixed and evaluated while being raised, a remarkable image defect was caused by writing with a ballpoint pen. Further, cracks were observed in the fixed image.

(Evaluation methods and standards)
-Writing resistance-
The fixed image was written with a ballpoint pen, the writing resistance level was visually confirmed, and judged according to the following criteria. For the paper, the product name “Mirror Coat Platinum” manufactured by Fuji Xerox Office Supply Co., Ltd. was used.
○: Image defect does not occur when writing with a ballpoint pen.
(Triangle | delta): The slight image defect is recognized with respect to writing of a ball-point pen.
X: Significant image defects occur with respect to writing with a ballpoint pen.

-Crack level-
The crack level was visually confirmed and judged according to the following criteria. For the paper, the product name “Mirror Coat Platinum” manufactured by Fuji Xerox Office Supply Co., Ltd. was used.
○: Cracks do not occur even during long-term storage.
X: Cracks occur immediately after fixing or after storage for several weeks.

The results of Examples C1 to C6 and Reference Examples C7 to C10 are shown in Tables 6 to 7.

These results, as the constituent material of the core particle, by a polymerization unit having a biphenyl skeleton with a predetermined amount, and applying the alkyl titanium, sintered-crystalline polyester resin you contain at least one alkyl tin and alkyl germanium, It can be seen that low-temperature fixing is achieved, and particularly when the paper is fixed on coated paper or cardboard, the image strength is excellent with respect to writing resistance, and cracks occur in the image even during long-term storage.

Claims (6)

In an electrophotographic toner having a core containing at least a colorant and a binder resin, and a shell layer containing a resin different from the binder resin on the surface of the core,
The shell layer is seen containing a polyester resin having a polymerization unit having a naphthalene skeleton,
The binder resin used for the core is a crystalline polyester resin,
The crystalline polyester resin has 0.3 to 10% by weight of a polymer unit having a naphthalene skeleton or a biphenyl skeleton, and 0.02 to 1.0% by weight of at least one of alkyl titanium, alkyl tin, and alkyl germanium. An electrophotographic toner characterized by comprising:   2. The electrophotographic toner according to claim 1, wherein the polyester resin used in the shell layer has 10 to 40 mol% of a polymer unit having the naphthalene skeleton.   The electrophotographic toner according to claim 1, wherein a glass transition temperature of the polyester resin used for the shell layer is 65 ° C. or more.   2. The electrophotographic toner according to claim 1, wherein the storage elastic modulus (G ′) at 85 ° C. of the toner is 100 Pa or more and 100,000 Pa or less, and the loss elastic modulus (G ″) is larger than the storage elastic modulus. An electrophotographic developer comprising the electrophotographic toner according to any one of claims 1 to 4 and a carrier. A latent image forming step for forming an electrostatic latent image on the surface of the latent image holding member and a developer carried on the developer carrying member are used to develop the electrostatic latent image formed on the surface of the latent image holding member. A developing step for forming a toner image, a transfer step for transferring the toner image formed on the surface of the latent image holding member to the surface of the transfer target, and a fixing step for thermally fixing the toner image transferred on the surface of the transfer target An image forming method comprising:
The developer, at least, an image forming method characterized by comprising the electrophotographic toner according to any one of claims 1-4.