JP7063735B2 - Manufacturing method of toner for static charge image development - Google Patents

Description

The present invention relates to a method for producing a toner for developing an electrostatic charge image. More specifically, the present invention relates to a method for producing a toner for static charge image development, which has little change in cohesiveness over a long period of time and is less likely to contaminate members.

Conventionally, toner used in electrophotographic printers and copiers has inorganic fine particles or organic fine particles added as an external additive in order to improve fluidity and control the amount of charge. The external additive adheres to the toner surface by mixing and stirring the toner with a mixer. Therefore, as the life of the image forming apparatus is extended, a spacer function is provided so that the external additive having a small particle size will not be buried and the durability will be improved, and the adhesiveness will not be excessively reduced. Large particle size external additives are being investigated. In particular, toner using a crystalline resin has high cohesiveness. Therefore, attempts have been made to reduce the cohesiveness of the toner by using an external additive having a large particle size.

However, the large particle size external additive is easier to desorb from the toner particles than the small particle size external additive, and the characteristics of the toner change after a large number of prints, or the desorbed large particle size external additive is an image. It may contaminate the members of the forming device and cause deterioration of image quality. In particular, toner using a crystalline resin tends to deteriorate in fluidity as a powder. Therefore, a technique has been proposed in which a resin shell advantageous for avoiding blocking or the like is formed on core particles made of a resin advantageous for heat fixing (Patent Document 1).

In addition, the outer shell, which is liberated by simply mixing with a mixer, contains resin particles that are non-spherical and have an outer shell layer on the surface in the outer shell step, and the outer shell layer is made of silica or modified silica. A technique has been proposed in which an electrophotographic toner characterized by being configured is used to firmly adhere to toner matrix particles, prevent release, and maintain printing performance (Patent Document 2).

Japanese Unexamined Patent Publication No. 2006-285188 Japanese Unexamined Patent Publication No. 2014-85551

However, with the technique described in Patent Document 1, it is difficult to fabricate a core-shell structure using only existing equipment. Further, the technique described in Patent Document 2 has a problem that a special surface treatment is required.

The present invention has been made in view of such conventional problems, and although existing equipment can be used and a crystalline resin is contained, there is little change in cohesiveness over a long period of time, and a member is provided. It is an object of the present invention to provide a method for producing a toner for static charge development for producing a toner for developing an electrostatic charge image which is less likely to be contaminated.

As a result of diligent studies to solve the above problems, the present inventors have made at least one of colloidal silica having a specific particle size range and fumed silica and titanium oxide having a specific particle size range. The present invention was completed by finding that the above-mentioned problems can be solved by firmly adhering colloidal silica to the toner particles by mechanochemical interaction and making it difficult to release by blending and pulverizing the classification. I let you. The present invention that solves the above problems mainly includes the following configurations.

(1) In a kneaded product containing a binder resin containing crystalline polyester, a colorant, and a mold release agent, colloidal silica having an average particle size of 100 to 130 nm, and fumed silica or titanium oxide having an average particle size of 10 to 40 nm. A method for producing a toner for static charge image development, in which at least one of them is blended and pulverized and classified.

According to such a configuration, it is possible to obtain a toner for static charge image development which has little change in cohesiveness over a long period of time and does not easily contaminate the member, even though it contains a crystalline resin.

(2) The method for producing an electrostatic charge image developing toner according to (1), wherein the pulverization classification is performed until the average particle size of the static charge image developing toner becomes 5 to 8 μm.

According to such a configuration, a toner for static charge image development, which has little change in cohesiveness and is less likely to contaminate the member, can be obtained in high yield, and the productivity is excellent.

(3) The colloidal silica is 1.0 to 3.0% by mass based on the kneaded product, and at least one of the fumed silica or titanium oxide is 1.0 to 3% based on the kneaded product. The method for producing a toner for static charge image development according to (1) or (2), which is added so as to be in an amount of 0.0% by mass.

According to such a configuration, the obtained toner has little change in cohesiveness and is less likely to contaminate the member.

(4) The method for producing a toner for static charge image development according to any one of (1) to (3), wherein the colloidal silica is surface-treated with hexamethyldisilazane.

According to such a configuration, the obtained toner has little change in chargeability over a long period of time.

(5) The method for producing a toner for static charge image development according to any one of (1) to (4), wherein the content of the crystalline polyester resin is 5 to 10% by mass in the binder resin.

According to such a configuration, the obtained toner is excellent in low temperature fixability and storage stability.

(6) The method for producing a toner for static charge image development according to any one of (1) to (5), further comprising a step of adding an external additive after the pulverization classification.

According to such a configuration, the obtained toner has good printability even when printed for a long period of time.

According to the present invention, it is possible to use existing equipment, and to produce a toner for static charge image development which has little change in cohesiveness over a long period of time and does not easily contaminate members even though it contains a crystalline resin. A method for producing a toner for electrostatic charge development can be provided.

<Manufacturing method of toner for static charge image development>
The method for producing a toner for developing an electrostatic charge image according to an embodiment of the present invention (hereinafter, also referred to as a method for producing a toner) includes a binder resin, a colorant, a mold release agent, a crystalline polyester, and a mold release agent. The kneaded product containing the above is blended with colloidal silica having an average particle diameter of 100 to 130 nm and at least one of fumed silica or titanium oxide having an average particle diameter of 10 to 40 nm, and pulverized and classified. .. The toner may be a two-component toner used in an image forming method in an electrophotographic method and used together with a carrier, or a one-component toner that does not use a carrier. Each will be described below.

-Binder resin The binder resin disperses the colorant contained in the toner and melts on the surface of the recording medium due to the heat of the fixing roller in the fixing process during printing and then solidifies to fix the colorant on the surface of the recording medium. Formulated to make it.

The binder resin includes a crystalline polyester resin. The binder resin may contain a binder resin other than the crystalline polyester resin in addition to the crystalline polyester resin.

The crystalline polyester resin of this embodiment is not particularly limited. As an example, the crystalline polyester resin preferably contains an alicyclic dibasic acid, sebacic acid, terephthalic acid, isophthalic acid and the like as an acid component. This can improve both the low temperature fixability and the storage stability of the toner.

Examples of the alicyclic dibasic acid include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, dimer acid and the like. Will be. Among these, the alicyclic dibasic acid is preferably 1,4-cyclohexanedicarboxylic acid because the softening point can be easily adjusted and the fixing property is good.

The alicyclic dibasic acid is preferably contained in a crystalline polyester resin in an amount of 3% by mass or more, and more preferably 5% by mass or more. The alicyclic dibasic acid is preferably contained in a crystalline polyester resin in an amount of 50% by mass or less, more preferably 40% by mass or less. When the content of the alicyclic dibasic acid is within the above range, the obtained toner is excellent in low temperature fixability and storage stability.

Terephthalic acid and isophthalic acid are preferably contained in a crystalline polyester resin in an amount of 20% by mass or more, more preferably 25% by mass or more. Further, terephthalic acid and isophthalic acid are preferably contained in a crystalline polyester resin in an amount of 70% by mass or less, more preferably 60% by mass or less. When the contents of terephthalic acid and isophthalic acid are within the above ranges, the obtained toner has excellent storage stability.

Other acid components can be used as long as the performance does not deteriorate.

In the crystalline polyester resin of the present embodiment, a conventionally known alcohol component can be used as the alcohol component. The alcohol component is preferably an aliphatic diol having 4 or more and 12 or less carbon atoms, preferably 1,2-butanediol and 1,3-butandio, from the viewpoint of improving both low-temperature fixing property and storage stability of the toner. -L, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-methyloctanediol , 1,10-decanediol and 2-butyl-2-ethyl-1,3-propanediol are more preferred.

The mass average molecular weight of the crystalline polyester resin is preferably 3000 or more. The mass average molecular weight of the crystalline polyester resin is preferably 30,000 or less. When the mass average molecular weight is less than 3000, the toner tends to have poor storage stability. On the other hand, when the mass average molecular weight exceeds 30,000, the low temperature fixability of the toner tends to decrease.

The content of the crystalline polyester resin is preferably 5% by mass or more in the binder resin. The content of the crystalline polyester resin is preferably 10% by mass or less in the binder resin. When the content is less than 5% by mass, the toner tends to be inferior in low temperature fixability. On the other hand, when the content exceeds 10% by mass, the toner tends to be inferior in storage stability.

The melting point of the crystalline polyester resin is not particularly limited. As an example, the melting point is preferably 65 ° C. or higher. The melting point is preferably 100 ° C. or lower. When the melting point is within the above range, the toner has good fixability. In this embodiment, the melting point can be calculated by measuring the melting temperature in thermal analysis using a differential scanning calorimeter. The binder resin is not particularly limited.

The method for producing the crystalline polyester resin is not particularly limited and can be produced by a general polyester polymerization method in which an acid component and an alcohol component are reacted, and examples thereof include a direct polycondensation method and a transesterification method. ..

The crystalline polyester resin can be produced in a polymerization temperature range of 180 ° C. or higher and 230 ° C. or lower. If necessary, the pressure inside the reaction system is reduced, and the reaction is carried out while removing water and alcohol generated during condensation. If the monomer dissolves or does not dissolve at the reaction temperature, a solvent having a high boiling point may be added as a dissolution aid to dissolve the monomer. The polycondensation reaction is carried out while distilling off the dissolution auxiliary solvent. When a monomer having poor compatibility is present in the copolymerization reaction, it is preferable to condense the monomer having poor compatibility with the monomer and an acid or alcohol to be polycondensed in advance, and then polycondensate the monomer together with the main component.

As catalysts that can be used in the production of crystalline polyester resins, alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; metals such as zinc, manganese, antimony, titanium, tin, zirconium and germanium. Compounds: Subphosphate compounds, phosphate compounds, amine compounds and the like, and specific examples thereof include the following compounds.

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 tetraethoxydo, titanium. Tetrapropoxide, Titanium tetraisopropoxide, Titanium tetrabutoxide, Antimonite trioxide, Triphenylantimon, Tributylantimon, Tin formate, Tin oxalate, Tetraphenyltin, Dibutyltin dichloride, Dibutyltin oxide, Diphenyltin oxide, Zirconite tetrabutoxide, Naften Zirconite Acid, Zirconil Carbonate, Zirconil Acetate, Zirconil Stearate, Zirconil Octylate, Germanium Oxide, Triphenylphosphite, Tris (2,4-t-butylphenyl) Phosphite, Ethyltriphenylphosphonium Bromide, Triethylamine, Triphenylamine Etc. can be mentioned.

The binder resin that can be used in combination with the crystalline polyester resin of the present embodiment is not particularly limited. As an example, the binder resin is a styrene-based copolymer such as polystyrene, a styrene-methyl acrylate copolymer, a styrene-acrylonitrile copolymer, a polyester resin other than the crystalline polyester resin of the present embodiment, or an epoxy resin. It is a resin material such as. These binder resins may be used in combination. Among these, polyester is preferable as the binder resin to be used in combination because it is easily colored and a toner having a vivid color can be obtained.

The binder resin of the present embodiment preferably contains a non-crystalline resin among the above resin materials. The amorphous resin is preferably a resin having a mass average molecular weight of 4000 to 150,000 and a softening point of 95 to 125 ° C. The mass average molecular weight is preferably 4000 or more, and more preferably 5000 or more. The mass average molecular weight is preferably 150,000 or less, and more preferably 12,000 or less. The softening point is preferably 90 ° C. or higher, more preferably 95 ° C. or higher. The softening point is preferably 125 ° C. or lower, more preferably 120 ° C. or lower. When the mass average molecular weight and the softening point are within the above ranges, the obtained toner exhibits excellent low temperature fixability and storage stability. In the present embodiment, the mass average molecular weight can be obtained by measuring, for example, gel permeation chromatography (GPC) and converting it into polystyrene. Examples of the apparatus for measuring the mass average molecular weight in terms of polystyrene by GPC include Water 2690 (manufactured by Waters) and PLgel 5 μL MIXED-D (manufactured by Polymer Laboratories) as a column. Also, the softening point can be measured according to ASTM E28-92.

The content of the binder resin other than the crystalline polyester resin of the present embodiment is not particularly limited. As an example, the content of the binder resin is preferably 75% by mass or more in the toner. The content of the binder resin is preferably 85% by mass or less in the toner. When the content of the binder resin is within the above range, the obtained toner can easily disperse the colorant appropriately and can be easily fixed on the recording medium.

-Coloring agent The coloring agent is blended to give the toner a coloring power. The colorant is not particularly limited. As an example, the colorants include colorants such as magnetic powders having a black color such as carbon black, colorants having a cyan color such as copper phthalocyanine, methylene blue and Victoria blue, rhodamine dyes, dimethylquinacridone, dichloroquinacridone and carmine red. Such as a colorant exhibiting a magenta color, a colorant exhibiting a yellow color such as benzidine yellow, chrome yellow, naphthol yellow, and disazo yellow. Colorants may be used in combination.

The content of the colorant is not particularly limited. As an example, the content of the colorant is preferably 0.1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin in the toner. Since various master batches in which a high-concentration pigment is dispersed in a resin in advance are commercially available, they may be purchased and used as a colorant. In this case, the amount of the pigment used can be determined in consideration of the concentration of the pigment contained in the masterbatch so that the concentration of the pigment contained in the toner is within the above range.

-Release agent The release agent is not particularly limited, and various known waxes can be used. For example, polyolefin waxes such as polyethylene wax and polypropylene wax, branched chain hydrocarbon waxes such as microcrystallin wax, long chain hydrocarbon waxes such as paraffin wax and sazole wax, and dialkyls such as distearyl ketone. Ketone wax, carnauba wax, montan wax, behenic acid behenate, trimethyl propantribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol di Examples thereof include ester waxes such as stearate, tristearyl trimellitic acid and distealyl maleate, and amide waxes such as ethylenediamine behenylamide and tristealylamide trimellitic acid. The release agent may be used in combination. Among these, as the mold release agent, an ester wax and a hydrocarbon wax are preferable.

The content of the release agent is not particularly limited. As an example, the content of the release agent can be usually in the range of 1 to 30 parts by mass, preferably in the range of 5 to 20 parts by mass with respect to 100 parts by mass of the binder resin. The content of the release agent in the toner particles is preferably in the range of 3 to 15% by mass. When the content of the mold release agent is within the above range, the obtained toner can obtain good mold release property between the fixing roller and the printed surface in the fixing process at the time of printing. In addition, the release agent is less likely to exude from the toner, and poor charging and filming are less likely to occur.

-Other components In addition to the above, the toner particles are, for example, a charge control agent. The charge control agent is suitably blended for adjusting the charge amount of the toner.

The charge control agent is not particularly limited. For example, the charge control agent is a metal complex such as niglosin, basic dye, monoazo dye, a salt or complex of a carboxylic acid such as salicylic acid or dicarboxylic acid and a metal such as chromium, zirconium, aluminum, etc., an organic dye, naphthen. These are resin-type charge control agents such as metal salts of acids and higher fatty acids, alkoxylated amines, quaternary ammonium salt compounds, and aromatic polycondensates. The charge control agent may be used in combination. Among these, the toner preferably contains a resin-type charge control agent from the viewpoint of charge stability.

The content of the charge control agent is not particularly limited. As an example, the content of the charge control agent may not be contained in the toner particles, but is preferably 0.5% by mass or more. The content of the charge control agent is preferably 8% by mass or less in the toner particles. When the content of the charge control agent is within the above range, the obtained toner has more excellent chargeability.

In the method for producing a toner of the present embodiment, first, these binder resins, colorants, mold release agents and other components which are optional components are mixed and kneaded. More specifically, first, in the kneading step, each component of the toner particles described above is melt-kneaded to produce a kneaded product. Various conventionally known mixing devices (for example, double-con mixer, V-type mixer, drum-type mixer, super mixer, Henschel mixer, Nowtamixer, Mechanohybrid (manufactured by Nippon Coke Industries Co., Ltd.), etc.) are used to mix each component. Can be. For melt kneading, batch kneaders such as pressurized kneaders and Bambary mixers and continuous kneaders can be used, and single-screw or twin-screw extruders have become the mainstream because of the advantage of continuous production. There is. For example, KTK type twin-screw extruder (manufactured by Kobe Steel, Ltd.), TEM type twin-screw extruder (manufactured by Toshiba Machine Co., Ltd.), PCM kneader (manufactured by Ikekai Co., Ltd.), twin-screw extruder (K). -C.K.), Co-kneader (Bus), Kneedex (Nippon Coke Industry Co., Ltd.), etc. As the toner material, a masterbatch containing the binder resin and the colorant may be used.

The obtained kneaded product is blended with colloidal silica having an average particle diameter of 100 to 130 nm and at least one of fumed silica or titanium oxide having an average particle diameter of 10 to 40 nm.

-Coloidal silica Colloidal silica has an average particle size of 100 to 130 nm. The average particle size of colloidal silica is the volume average particle size, and can be measured by the BET method based on JIS Z 8830.

The average particle size of colloidal silica may be 100 nm or more, preferably 110 nm or more. The average particle size of colloidal silica may be 130 nm or less, preferably 120 nm or less. When the average particle size of colloidal silica is less than 100 nm, the toner tends to have high cohesiveness. On the other hand, when the average particle size of colloidal silica exceeds 130 nm, colloidal silica is easily desorbed from the toner surface.

The content of colloidal silica is not particularly limited. As an example, the content of colloidal silica is preferably 1.0% by mass or more, more preferably 1.2% by mass or more, based on the kneaded product. The content of colloidal silica is preferably 3.0% by mass or less, more preferably 2.5% by mass or less, based on the kneaded product. When the content of colloidal silica is within the above range, the toner has little change in cohesiveness over a long period of time.

The colloidal silica used in this embodiment may be surface-treated. The surface treatment is not particularly limited. As an example, the surface treatment is a surface treatment with hexamethyldisilazane, polydimethylsiloxane (silicon oil), octylluetosixylan and the like. Among these, by performing the surface treatment with hexamethyldisilazane, the charged amount of the toner is stable for a long period of time. The surface treatment method is not particularly limited.

-Fumed Silica and Titanium Oxide In the method for producing the toner of the present embodiment, at least one of fumed silica and titanium oxide is blended. These fumed silica and titanium oxide have an average particle size of 10 to 40 nm. The average particle size of fumed silica and titanium oxide is the volume average particle size, and can be measured by the BET method based on JIS Z 8830.

The average particle size of the fumed silica may be 10 nm or more, preferably 12 nm or more. The average particle size of fumed silica may be 40 nm or less, preferably 35 nm or less. Fumeed silica When the average particle size of silica is less than 10 nm, it does not adhere uniformly to the toner surface and the chargeability tends to decrease. On the other hand, when the average particle size of fumed silica exceeds 40 nm, the productivity of the toner during pulverization and classification tends to decrease.

The average particle size of titanium oxide may be 10 nm or more, preferably 15 nm or more. The average particle size of titanium oxide may be 40 nm or less, preferably 35 nm or less. When the average particle size of titanium oxide is less than 10 nm, it does not adhere uniformly to the toner surface and the chargeability tends to decrease. On the other hand, when the average particle size of titanium oxide exceeds 40 nm, the productivity of the toner during pulverization and classification tends to decrease.

The content of fumed silica is not particularly limited. As an example, the content of fumed silica is preferably 1.0% by mass or more, more preferably 1.5% by mass or more, based on the kneaded product. The content of fumed silica is preferably 3.0% by mass or less, more preferably 2.5% by mass or less, based on the kneaded product. When the content of fumed silica is within the above range, the toner has good chargeability and productivity at the time of pulverization and classification.

The content of titanium oxide is not particularly limited. As an example, the content of titanium oxide is preferably 0.2% by mass or more, more preferably 0.3% by mass or more, based on the kneaded product. The content of titanium oxide is preferably 1.0% by mass or less, more preferably 0.6% by mass or less, based on the kneaded product. When the content of titanium oxide is within the above range, the toner has good chargeability and productivity at the time of pulverization and classification is also good.

In this embodiment, at least one of fumed silica and titanium oxide may be used, and either one may be used. When both are used, the preferred range of content described above is the sum of both contents.

The fumed silica used in this embodiment may be surface-treated. The surface treatment is not particularly limited. As an example, the surface treatment is a surface treatment with hexamethyldisilazane, dimethyldichlorosilane, polydimethylsiloxane (silicon oil), octtiltrietosixylan and the like. Among these, by performing surface treatment with polydimethylsiloxane (silicon oil), the amount of charge of the toner is stable for a long period of time. The surface treatment method is not particularly limited.

Returning to the description of the production method, in the toner production method of the present embodiment, these colloidal silica, fumed silica, or titanium oxide are blended in the kneaded product. After that, the kneaded product is pulverized and classified.

The pulverization classification method is not particularly limited. For example, crushing is performed by coarsely crushing with a crusher such as a crusher, hammer mill, or feather mill, and then further, Cryptron System (manufactured by Kawasaki Heavy Industries, Ltd.) and Super Rotor (manufactured by Nisshin Engineering Co., Ltd.). , Turbo mill (manufactured by Freund Turbo Co., Ltd.) or crushing with an air jet crusher). The powder (crushed material) obtained in the crushing step is classified (for example, inertial classification type elbow jet (manufactured by Nittetsu Mining Co., Ltd.), centrifugal force classification method turboplex (manufactured by Hosokawa Micron Co., Ltd.)). , TSP separator (manufactured by Hosokawa Micron Co., Ltd.), faculty (classified using a classifier such as Hosokawa Micron Co., Ltd.) or a sieving machine).

The pulverization classification is preferably carried out until the volume median particle diameter (D50) of the toner particles is 5 to 8 μm. As a result, the toner yield at the time of pulverization and classification is excellent. In the present embodiment, the volume median particle size (D50) is also referred to as a volume-based median diameter, which is the total volume of particles having a diameter smaller than this value and the total volume of particles having a diameter larger than this value. Indicates a value of 50% of the total volume of the whole. The volume median particle size (D50) can be calculated by measuring the particle size distribution. As the particle size distribution measuring device, "Multisizer 3" manufactured by Beckman Coulter can be mentioned.

It is preferable that the toner manufacturing method of the present embodiment employs a step of further adding an external additive after pulverization and classification.

-External additive The external additive adheres to the surface of the toner particles and improves the charging characteristics of the toner particles, or exists in a state of being separated from the toner particles to improve the fluidity of the toner and improve the printability. It is compounded to make it.

The external additive is not particularly limited. As an example, the external additive is a negatively charged lubricant particle, a positively charged lubricant particle, an inorganic oxide particle or the like. External additives may be used in combination. The external additive is appropriately selected and used according to the model and purpose.

The positively charged lubricant particles are lubricant particles that are positively charged by triboelectric charging between the carrier and the charging blade. Such lubricant particles are known, and metal salt particles of fatty acids are preferably exemplified. As an example of such a metal salt of fatty acid, zinc stearate, aluminum stearate, calcium stearate, magnesium stearate, zinc laurate, zinc myristate, zinc palmitate, zinc oleate and the like are preferably mentioned, and among them, stearic acid. Zinc and magnesium stearate are more preferred. The positively charged lubricant particles may be of a single type or may be a combination of two or more types.

Negatively charged lubricant particles are lubricant particles that are negatively charged by triboelectric charging between carriers and charging blades. Such lubricant particles are known, and polytetrafluoroethylene (PTFE), silicone, boron nitride, polymethylmethacrylate (PMMA), polyvinylidene fluoride are preferably exemplified, and among them, boron nitride and polytetrafluoroethylene are preferable. (PTFE) is more preferably exemplified. The negatively charged lubricant particles may be of a single type or may be a combination of two or more types.

The inorganic oxide particles are not particularly limited. For example, the inorganic oxide particles include silica, alumina, titania, zirconia, zinc oxide, chromium oxide, cerium oxide, antimony oxide, tungsten oxide, tin oxide, tellurium oxide, manganese oxide, and boron oxide. Inorganic oxide particles may be used in combination. Among these, the inorganic oxide particles are preferably silica or titania from the viewpoint of excellent fluidity and excellent chargeability of the toner.

It is preferable that the surface of the inorganic oxide particles is hydrophobized. The method of hydrophobizing treatment is not particularly limited. As an example, in the method of hydrophobizing treatment, a conventionally known hydrophobizing agent is brought into contact with the surface of the inorganic oxide particles before the hydrophobizing treatment, and hydrophobic functional groups and components are brought into contact with the inorganic oxide particles. It is a method of chemically bonding or adhering to the surface. The hydrophobizing agent for hydrophobizing the inorganic oxide particles is not particularly limited. As an example, the hydrophobizing agent is octyltriethoxysilane, polydimethylsiloxane, dimethyldichlorosilane, hexamethyldisilazane and the like. The hydrophobizing agent may be used in combination.

The amount of the external additive added in the present embodiment (when a plurality of external agents are used, the total amount added) is preferably in the range of 0.05 to 5 parts by mass with respect to 100 parts by mass of the toner. , 0.1 to 3 parts by mass, more preferably. When the content of the external additive is within the above range, the obtained toner has good fluidity, chargeability, cleaning property and the like.

As described above, according to the toner manufacturing method of the present embodiment, toner can be manufactured using the same equipment as the existing equipment without requiring special equipment. Although the obtained toner contains a crystalline resin, there is little change in cohesiveness over a long period of time, and the member is less likely to be contaminated.

Hereinafter, the present invention will be described in more detail with reference to Examples. The present invention is not limited to these examples. Unless otherwise specified, "%" means "% by mass" and "part" means "part by mass".

The raw materials used and the preparation method are shown below.
<Binder resin>
Crystalline polyester resin Crystalline polyester resin 1: Polyester containing cyclohexanedicarboxylic acid, isophthalic acid, terephthalic acid and 1,4-butanediol (mass average molecular weight 30,000, melting point 96 ° C)
Crystalline polyester 2: Polyester with sebacic acid and 1,10-decanediol (mass average molecular weight 3,000, melting point 74 ° C)
Amorphous binder resin used in combination Non-crystalline binder resin 1: Commercially available non-crystalline polyester resin (Tg 64 ° C, molecular weight 5500)
Amorphous binder resin 2: Commercially available amorphous polyester resin (Tg 65 ° C., molecular weight 110,000)
<Charge control agent>
Product name Copper Charge N5P-01 (manufactured by Clariant Chemicals)
<Colorant>
Benzimidazolone yellow pigment masterbatch (pigment content 50% by mass, resin: amorphous polyester)
Carmine 6B Pigment Masterbatch (Pigment content: 40% by mass, Resin: Amorphous polyester resin)
Dimethylquinacridone pigment masterbatch (pigment content: 45% by mass, resin: non-crystalline polyester resin)
Copper phthalocyanine blue pigment masterbatch (pigment content 50% by mass, resin: amorphous polyester)
<Release agent>
Release agent 1: Fatty acid ester wax (melting point 69 ° C)
Release agent 2: Hydrocarbon wax (melting point 98 ° C)
<External agent>
External agent 1: Silica particles surface-treated with alkylsilane (particle size 115 nm colloidal silica)
External additive 2: Silica particles surface-treated with silicone oil (particle size: 12 nm fumed silica)
External agent 3: Titanium oxide particles surface-treated with alkylsilane (particle size 35 nm)
External additive 4: Silica particles surface-treated with alkylsilane (particle size 80 nm colloidal silica)
External additive 5: Silica particles surface-treated with silicone oil (particle size: 28 nm fumed silica)
External agent 6: Silica particles surface-treated with dimethyldichlorosilane (particle size 12 nm fumed silica)
External additive 7: Titanium oxide particles surface-treated with alkylsilane (particle size 15 nm)
External additive 8: Acrylic resin fine particles (particle size 100 nm)

<Toner manufacturing method>
(Example 1)
Non-crystalline polyester resin 1 is 49.4%, non-crystalline polyester resin 2 is 19.8%, crystalline polyester resin 1 is 7%, mold release agent 1 is 5%, mold release agent 2 is 2%, and is charged. 15.8% of the control agent (containing 1% of the control agent and 50% by mass of the benzimidazolone yellow pigment master batch) was mixed with a Henshell mixer and then melt-kneaded using a twin-screw kneader. The obtained kneaded product was coarsely pulverized with a rotoplex. To the coarsely crushed product, 1.3% of the external preparation agent 1, 2.3% of the external preparation agent 2 and 0.4% of the external preparation agent 3 were added, and the mixture was stirred with a Henschel mixer for 2 minutes to discharge the coarsely crushed product. Then, it was finely pulverized with a jet mill and classified using a wind power classifier to obtain toner particles having a volume average particle diameter of 6.5 μm. To the obtained toner particles, 1.0% of the external additive 5, 0.5% of the external additive 6, 0.75% of the external additive 7, and 0.75% of the external additive 8 were added, and a Henshell mixer was added. The mixture was stirred for 10 minutes to obtain toner (yellow toner).

(Examples 2 to 5, Comparative Examples 1 to 4)
Toners were obtained by the same method as in Example 1 except that the formulations were changed to those shown in Table 1.

With respect to the toners of Examples 1 to 5 and Comparative Examples 1 to 4, the image density, toner consumption and fog were evaluated by the following evaluation methods. The results are shown in Table 1.

<Image density (when printing 5,000 sheets)>
After printing 5,000 sheets of ISO chart ISO-IEC24712 in an environment of temperature 25 ° C and humidity 50% using a non-magnetic two-component negative charging copier for evaluation, a solid image is printed and reflected. The image density was measured and evaluated with a densitometer RD-914 (manufactured by Macbeth).
(Evaluation criteria)
◯: The image density was 1.2 or more.
Δ: The image density was 1.1 or more and less than 1.2.
X: The image density was less than 1.1.

<Image density (when printing 50,000 sheets)>
After printing 50,000 sheets of ISO chart ISO-IEC24712 in an environment of temperature 25 ° C and humidity 50% using a non-magnetic two-component negative charging copier for evaluation, a solid image is printed and reflected. The image density was measured and evaluated with a densitometer RD-914 (manufactured by Macbeth).
(Evaluation criteria)
◯: The image density was 1.2 or more.
Δ: The image density was 1.1 or more and less than 1.2.
X: The image density was less than 1.1.

<Toner consumption (when printing 5,000 sheets)>
After printing 5,000 sheets of ISO chart ISO-IEC24712 in an environment of temperature 25 ° C. and humidity 50% using a non-magnetic two-component negative charging type copier for evaluation, ISO chart ISO-IEC24712 is printed on 1 sheet. The mass consumed by the toner when printing 000 sheets was measured and evaluated.
(Evaluation criteria)
◯: The toner consumption was less than 20 g / 1000 sheets.
Δ: The toner consumption was 20 g / 1000 sheets or more and 25 g / 1000 sheets or less.
X: The toner consumption was 25 g / 1000 sheets or more.

<Toner consumption (when printing 50,000 sheets)>
After printing 50,000 sheets of ISO chart ISO-IEC24712 in an environment of temperature 25 ° C. and humidity 50% using a non-magnetic two-component negative charging type copier for evaluation, ISO chart ISO-IEC24712 is printed on 1 sheet. The mass consumed by the toner when printing 000 sheets was measured and evaluated.
(Evaluation criteria)
◯: The toner consumption was less than 20 g / 1000 sheets.
Δ: The toner consumption was 20 g / 1000 sheets or more and 25 g / 1000 sheets or less.
X: The toner consumption was 25 g / 1000 sheets or more.

<Fog (when printing 5,000 sheets)>
After printing 5,000 sheets of ISO chart ISO-IEC24712 in an environment of temperature 25 ° C and humidity 50% using a non-magnetic two-component negative charging copier for evaluation, the occurrence of fog was observed. ..
(Evaluation criteria)
◯: No fog was observed.
×: Fog, which is a problem in actual use, was observed.
Δ: It was slightly recognized by magnifying and observing.

<Fog (when printing 50,000 sheets)>
After printing 50,000 sheets of ISO chart ISO-IEC24712 in an environment of temperature 25 ° C and humidity 50% using a non-magnetic two-component negative charging copier for evaluation, the occurrence of fog was observed. ..
(Evaluation criteria)
◯: No fog was observed.
×: Fog, which is a problem in actual use, was observed.
Δ: It was slightly recognized by magnifying and observing.

As shown in Table 1, the toners of Examples 1 to 5 contained a crystalline polyester resin. In each case, the image density was high, the toner consumption was low, and no fog was observed. Therefore, it was found that these toners have little change in cohesiveness over a long period of time and are less likely to contaminate the members. On the other hand, the toners of Comparative Examples 1 to 4 in which colloidal silica having an average particle diameter of 100 to 130 nm was not added at the time of toner kneading had a large toner consumption.

Claims (6)

Prepare a kneaded product containing a binder resin containing crystalline polyester, a colorant, and a mold release agent.
The kneaded product is coarsely prepared before blending colloidal silica having an average particle diameter of 100 to 130 nm and at least one of fumed silica having an average particle diameter of 10 to 40 nm or titanium oxide having an average particle diameter of 10 to 40 nm. Crush and
A method for producing a toner for static charge image development , wherein the colloidal silica and at least one of the fumed silica and the titanium oxide are mixed with the kneaded product after coarse pulverization and pulverized and classified. The method for producing a toner for static charge image development according to claim 1, wherein the pulverization classification is performed until the average particle size of the toner for static charge image development becomes 5 to 8 μm. The colloidal silica was added to the kneaded product in an amount of 1.0 to 3.0% by mass, and
The toner for static charge image development according to claim 1 or 2, wherein at least one of the fumed silica and titanium oxide is added to the kneaded product in an amount of 1.0 to 3.0% by mass. Method. The method for producing a toner for static charge image development according to any one of claims 1 to 3, wherein the colloidal silica is surface-treated with alkylsilane . The method for producing a toner for static charge image development according to any one of claims 1 to 4, wherein the content of the crystalline polyester resin is 5 to 10% by mass in the binder resin. The method for producing a toner for static charge image development according to any one of claims 1 to 5, further comprising a step of adding an external additive after the pulverization classification.