JP2014041238A - Toner for electrostatic charge image development and production method of toner for electrostatic charge image development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development and a production method of the toner capable of inhibiting troubles due to charging abnormality of toner particles, a filming phenomenon on a photoreceptor, or the like caused by changes in a printing environment or increase in the number of prints.SOLUTION: The toner comprises toner base particles containing a binder resin, a colorant, a release agent and a charge control agent, and an external additive. As the external additive, the toner includes predetermined amounts of hydrophobized inorganic oxide particles (A) having an average primary particle diameter of 100 nm to 200 nm and a circularity coefficient of 0.900 to 1.000 and hydrophobized inorganic oxide particles (B) having an average primary particle diameter of 5 nm to 50 nm. The release agent shows a melting temperature of 60°C to 75°C measured by use of a differential scanning calorimeter and is included by 3 to 12 parts by mass in 100 parts by mass of the toner base particles.

Description

  The present invention relates to an electrostatic image developing toner and a method for producing an electrostatic image developing toner.

  The electrophotographic image forming method is widely used in various printers, copiers, facsimiles, and the like because high-quality images and printing can be obtained at high speed. In this image forming method, an electrostatic charge image is formed by performing exposure according to a desired image on the surface of a charged photoreceptor, and then the electrostatic charge image developing toner (hereinafter simply referred to as an electrostatic charge image developing toner). The toner image is formed on the surface of the photosensitive member by electrostatically adhering the toner. Next, the toner image is transferred to a recording medium such as paper, whereby a desired image is formed on the recording medium. Thereafter, excess toner remaining on the surface of the photoreceptor is removed by a cleaning blade before the next image is formed on the surface of the photoreceptor.

  The toner image formed on the recording medium is fixed on the recording medium through a fixing process in which heat and pressure are applied by a fixing roll. In recent years, from the viewpoint of energy saving, it is required to lower the heating temperature in the fixing process, that is, the fixing temperature. Along with this, it is necessary to lower the melting point and increase the amount of the release agent (wax) contained in the toner to be used in order to ensure releasability from the fixing roll. As such a release agent for toner, for example, Patent Document 1 proposes a hydrocarbon wax having an average carbon number of 30 to 40 and having a predetermined melting temperature in a differential scanning calorimeter.

  The release agent is usually contained in the toner base particles together with a binder resin, a color pigment, a charge adjusting agent and the like. The toner base particles are mixed with inorganic oxide particles such as silica for the purpose of improving the fluidity of the toner and improving the charge characteristics. These inorganic oxide particles and the like are called external additives. For example, in Patent Document 2, the role of the external additive is attached to the surface of the toner base particles to maintain the charge characteristics of the toner, and the role of the external additive is provided between the toner base particles to improve the toner fluidity. It has been proposed to use an external additive having a plurality of average particle sizes according to these roles.

JP 2001-051445 A JP 2011-197371 A

  By the way, apparatuses such as the above-mentioned printers using electrophotography are used in various environments. Under such circumstances, when the toner using the release agent having a low melting point as described above is used, the printing environment may be in a high temperature and high humidity state, or the stirring stress accompanying the increase in the number of printed sheets may be applied to the toner. In this case, the release agent may be detached from the toner base particles inside the developing unit in which the toner is accommodated, and the toner may be aggregated accordingly. In that case, the toner charge amount distribution is non-uniform, the toner is scattered in the apparatus, the toner consumption is increased, and the non-image area is contaminated (so-called background contamination). Leads to. Further, as the release agent is detached from the toner base particles, the external additive is buried in the surface of the toner base particles or contaminated with the release agent, and cleaning of the surface of the photosensitive member by the cleaning blade is not performed. In some cases, a filming phenomenon may occur in which a toner thin film is formed on the surface of the photoreceptor.

  The present invention has been made in view of the above circumstances, and can suppress troubles due to abnormal charging of toner particles, filming phenomenon on a photoconductor, and the like accompanying changes in the printing environment and an increase in the number of copies to be printed. An object of the present invention is to provide a toner for developing an electrostatic image and a method for producing the same.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have added a release agent having a specific melting temperature to the toner base particles, and have a hydrophobic treatment having two different average primary particle sizes. It was found that the above problems can be solved by using the inorganic oxide particles thus prepared as an external additive, and by increasing the circularity coefficient of the inorganic oxide particles having a larger average primary particle size among them. It came to complete.

  The present invention comprises toner base particles containing a binder resin, a colorant, a release agent and a charge control agent, and an external additive. The external additive has an average primary particle diameter of 100 nm to 200 nm and a circularity coefficient. Hydrophobized inorganic oxide particles A having 0.900 to 1.000 and hydrophobic treated inorganic oxide particles B having an average primary particle diameter of 5 nm to 50 nm, The content is 2 to 10 parts by mass with respect to 100 parts by mass of the toner base particles, and the content of the inorganic oxide particles B is 0.3 to 5 parts by mass with respect to 100 parts by mass of the toner base particles. The total content of the inorganic oxide particles A and B is 2.3 to 12 parts by mass with respect to 100 parts by mass of the toner base particles, and the release agent is melted at 60 ° C. to 75 ° C. in a differential scanning calorimeter. 100 parts by mass of toner base particles having a temperature To include 3 to 12 parts by weight, a toner for developing electrostatic images.

  The average primary particle diameter of the inorganic oxide particles B is preferably 5 nm to 20 nm.

  The total content of the inorganic oxide particles A and B is preferably 2.3 to 10 parts by mass with respect to 100 parts by mass of the toner base particles.

  The inorganic oxide particles A and B are preferably silica.

  The inorganic oxide particles A are preferably those that have been hydrophobized with octyltriethoxysilane or polydimethylsiloxane.

  The inorganic oxide particles B are preferably those that have been hydrophobized with dimethyldichlorosilane or hexamethyldisilazane.

  The volume-median particle diameter D50 of the toner base particles is 4.5 μm to 8.0 μm, and the number% of toner base particles having a particle diameter of 4.0 μm or less with respect to the total number of toner base particles is 35% or less. Preferably there is.

  Moreover, this invention contains binder resin, a coloring agent, the mold release agent whose melting temperature in a differential scanning calorimeter is 60 to 75 degreeC, and a charge control agent, and the said mold release agent is 3-12 mass%. A kneading step of melt kneading the mixture to obtain a kneaded product, a pulverizing and classifying step of pulverizing and classifying the kneaded product to obtain toner base particles, and an average primary particle diameter of 100 nm to 200 nm with respect to the toner base particles. Hydrophobized inorganic fine particles A having a circularity coefficient of 0.900 to 1.000 and 2 to 10 parts by weight with respect to 100 parts by weight of the toner base particles, and an average primary particle diameter of 5 to 50 nm. And an external addition step of adding 0.3 to 5 parts by mass of the inorganic fine particles B subjected to the conversion treatment to 100 parts by mass of the toner base particles, and a mixing process.

  According to the present invention, a toner for developing an electrostatic charge image capable of suppressing troubles due to abnormal charging of toner particles, filming phenomenon on a photosensitive member, etc. accompanying changes in the printing environment and an increase in the number of copies to be printed, and a method for producing the same Is provided.

  Hereinafter, an embodiment of the toner for developing an electrostatic charge image and an embodiment of a method for producing the toner for developing an electrostatic charge image of the present invention will be described.

<Toner for electrostatic image development>
The electrostatic image developing toner of the present invention (as described above, also simply referred to as “toner”) may be a two-component toner used in an electrophotographic image forming method and used with a carrier. One-component toner that does not use a carrier may be used. However, according to the toner of the present invention, it is possible to suppress toner charging abnormality caused by contamination of the carrier with the release agent released from the toner. From this viewpoint, the toner of the present invention is It is preferably used as a two-component toner. The toner of the present invention may be a magnetic toner containing a magnetic material or a non-magnetic toner containing no magnetic material.

  The toner of the present invention comprises toner base particles containing a binder resin, a colorant, a release agent and a charge control agent, and external additives which are inorganic oxide particles. Hereinafter, each component will be described. In the present specification, particles obtained by kneading and pulverizing and classifying materials such as a binder resin, a colorant, a release agent, and a charge control agent are referred to as toner base particles, and are externally added to the toner base particles. A mixture obtained by adding an agent is referred to as toner (electrostatic image developing toner).

[Binder resin]
The binder resin is also called a binder and is one of the components contained in the toner base particles. The binder resin disperses the colorant contained in the toner base particles and solidifies after being melted on the surface of the recording medium by the heat of the fixing roller in the fixing process during printing, thereby fixing the colorant on the surface of the recording medium. Let

  The binder resin used in the toner of the present invention is not particularly limited, and conventionally known resins can be exemplified. Examples of such a binder resin include styrene copolymers such as polystyrene, styrene-methyl acrylate copolymer, styrene-acrylonitrile copolymer, and resin materials such as polyester and epoxy resin. These binder resins can be used alone or in combination of two or more. Among these binder resins, polyester can be preferably exemplified from the viewpoint that it is easy to color and a toner having a clear color can be obtained.

  The polyester can be obtained by polymerizing a monomer composition comprising a dihydric or higher polyhydric alcohol and a polybasic acid.

  Examples of the dihydric alcohol used for polyester polymerization include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1 Diols such as 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, bisphenol A alkylene such as bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A An oxide adduct etc. can be mentioned.

  Examples of the trihydric or higher polyhydric alcohol include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4. -Butanetriol, 1,2,5-pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxy Mention may be made of methylbenzene and the like.

  Examples of the divalent polybasic acid include maleic acid, fumaric acid, citraconic acid, itaconic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, and anhydrides of these acids. .

  Examples of the tribasic or higher polybasic acid include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, and 2,5,7-naphthalenetricarboxylic acid. Acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2, Examples include 7,8-octanetetracarboxylic acid and anhydrides of these acids.

  The addition amount of the binder resin in the toner base particles may be appropriately set in consideration of the performance required for the toner, but as an example, it is 50 to 95 parts by weight in 100 parts by weight of the toner base particles. Can be mentioned.

[Colorant]
The colorant gives coloring power to the toner and is one of the components contained in the toner base particles. The colorant used in the toner of the present invention is not particularly limited, and conventionally known colorants can be exemplified.

  Specifically, carbon black, black magnetic powder, etc. are exemplified as the black colorant, and copper phthalocyanine, methylene blue, Victoria blue, etc. are exemplified as the material of the cyan colorant, and the magenta colorant. Examples include rhodamine dyes, dimethylquinacridone, dichloroquinacridone, and carmine red. Examples of yellow colorants include benzidine yellow, chrome yellow, naphthol yellow, and disazo yellow. In addition, a colorant according to a desired color can be appropriately selected and used.

  The addition amount of the colorant in the toner base particles may be appropriately set in consideration of performance such as coloring power required for the toner, etc. As an example, 1 to 15 masses per 100 mass parts of the toner base particles. Part.

[Release agent]
The release agent is also called a wax and is one of the components contained in the toner base particles. The release agent is used for enhancing the release property between the fixing roller and the printing surface (recording medium such as paper) in the fixing process during image formation or printing.

  The release agent used in the toner of the present invention has a melting temperature of 60 ° C. to 75 ° C. in a differential scanning calorimeter. As a result, the temperature of the fixing roller in the fixing process during printing can be lowered, and the amount of energy used can be reduced. More preferably, the release agent has a melting temperature of 62 ° C. to 73 ° C. in a differential scanning calorimeter. The melting temperature was determined by using a differential scanning calorimeter (in this embodiment, DSC6200 manufactured by SII Nano Technology Co., Ltd.) (hereinafter also referred to as “DSC”) and room temperature (30). C.) to 160 [deg.] C. at a rate of temperature increase of 10 [deg.] C. per minute, and can be determined as the melting peak temperature in the input compensated differential scanning calorimetry shown in JIS K-7121.

  The release agent used in the toner of the present invention is not particularly limited as long as it has the above melting temperature, and conventionally known release agents can be exemplified. Such release agents include polyolefin waxes such as polyethylene and polypropylene, hydrocarbon waxes such as Fischer-Tropsch wax, microcrystalline wax, and paraffin wax, pentaerythritol behenate, behenyl behenate, behenyl citrate, and montan. Examples include ester waxes such as ester wax, carnauba wax, rice wax, and sazol wax. These release agents can be used alone or in combination of two or more. Among these release agents, polyethylene waxes can be preferably exemplified.

  The addition amount of the release agent in the toner base particles is 3 to 12 parts by mass with respect to 100 parts by mass of the toner base particles. When the addition amount of the release agent is within this range, a good release property between the fixing roller and the printing surface can be obtained in the fixing process during image formation or printing, and the release agent is eluted from the toner base particles. Various troubles such as charging failure and filming associated therewith can be suppressed. The addition amount of the release agent in the toner base particles is more preferably 3 to 10 parts by weight, and further preferably 3.5 to 8 parts by weight with respect to 100 parts by weight of the toner base particles. )

[Charge control agent]
The charge adjusting agent is added to adjust the charge amount of the toner, and is one of the components contained in the toner base particles. The charge adjusting agent used in the toner of the present invention is not particularly limited, and conventionally known ones can be exemplified.

  Such charge control agents include nigrosine, basic dyes, metal complexes such as monoazo dyes, salts or complexes of carboxylic acids such as salicylic acid and dicarboxylic acids with metals such as chromium and zirconium, organic dyes, naphthenic acids and higher grades. Examples include resin-type charge control materials such as metal salts of fatty acids, alkoxylated amines, quaternary ammonium salt compounds, and aromatic polycondensates. Such charge control agents can be used alone or in combination of two or more.

  The addition amount of the charge adjusting agent in the toner base particles may be appropriately set in consideration of the performance required for the toner. As an example, 0.5 to 8 parts by weight in 100 parts by weight of the toner base particles Can be mentioned.

[Preparation of toner base particles]
The toner base particles are mixed with each of the above components using a mixer such as a Henschel mixer, and after performing a kneading step of melting and kneading under heating using a kneader such as a twin screw extruder or a three roll mill, The kneaded product obtained is prepared by a pulverization and classification step of pulverizing and classifying with a pulverizer. In performing the kneading step, other components may be added in addition to the above components in consideration of characteristics such as performance required for the toner.

  There is no restriction | limiting in particular as a grinder used for the grinding | pulverization of a kneaded material, For example, a jet mill, a turbo mill, a rotor-type grinder etc. can be mentioned.

  As the particle size distribution of the toner base particles after pulverization and classification, the toner base having a volume median particle diameter D50 of 4.5 μm to 8.0 μm and a particle diameter of 4.0 μm or less with respect to the total number of toner base particles. It can be mentioned preferably that the number% of the particles is 35% or less. It is preferable that the particle size distribution of the toner base particles be in this range because the toner consumption can be suppressed and the transfer of the toner to the non-image area accompanying the increase in the toner charge amount distribution can be suppressed. A more preferable particle size distribution of the toner base particles is a number% of the toner base particles having a volume median particle diameter D50 of 5.5 μm to 7 μm and a particle diameter of 4.0 μm or less with respect to the total number of toner base particles. It can be mentioned that it is 30% or less. The volume median particle diameter D50 indicates a value in which the total volume of particles smaller than this value and the total volume of particles larger than this value are 50% of the total volume. The volume median particle diameter D50 and the number% of toner base particles having a particle diameter of 4.0 μm or less with respect to the total number of toner base particles are calculated by measuring the particle size distribution.

[External additive]
Next, the external additive will be described. The external additive is a particle component constituting the toner together with the toner base particles when added to the toner base particles, and is an inorganic oxide particle. In the present invention, as external additives, the hydrophobized inorganic oxide particles A having an average primary particle diameter of 100 nm to 200 nm and a circularity coefficient of 0.900 to 1.000, and an average primary particle diameter of 5 nm to 50 nm. At least two kinds of inorganic fine particles with the hydrophobized inorganic oxide particles B are used as external additives. That is, in the present invention, the above-mentioned two types of inorganic oxide particles A and B having different average primary particle diameters are used. Hereinafter, these inorganic oxide particles will be described.

[Inorganic oxide particles A]
The inorganic oxide particles A have a large average primary particle size among the inorganic oxides A and B. The inorganic oxide particles A are considered to exist in the toner mainly in a state of weakly adhering to the surface of the toner base particles or separated from the toner base particles, and cover the surface of the toner base particles where the release agent is exposed. Thus, it is considered that the carrier surface is prevented from being contaminated by the release agent, and that the toner dispersion stability is improved by being interposed between the carrier and the toner base particles. As a result, the inorganic oxide particles A contribute to uniformizing and stabilizing the charge amount of the toner, or slightly improving the cleaning effect of the surface of the photoreceptor by the cleaning blade by polishing the surface of the photoreceptor slightly, It is thought that the effect of improving the fluidity of the material is expressed.

  Examples of the inorganic oxide particles A include silica, alumina, titania, zirconia, zinc oxide, chromium oxide, cerium oxide, antimony oxide, tungsten oxide, tin oxide, tellurium oxide, manganese oxide, and boron oxide. Among these, silica can be mentioned preferably. The inorganic oxide particles A can be used alone or in combination of two or more.

  The average primary particle diameter of the inorganic oxide particles A is 100 nm to 200 nm. When the average primary particle diameter of the inorganic oxide particles A is within this range, the toner charge amount is made uniform and stabilized, the filming is suppressed as the cleaning effect on the surface of the photoreceptor is enhanced, and the toner flow The effect of improving the property can be obtained. The average primary particle diameter of the inorganic oxide particles A is preferably 100 to 180 nm, and more preferably 100 to 150 nm.

  In the present invention, the average primary particle diameter is an arbitrary value from an image obtained by photographing particles to be measured using a scanning electron microscope (SEM; manufactured by Hitachi Science Systems, S-3000FBN). The particle diameter of 100 particles was measured, and the average value per one of the measured particle diameters was obtained.

  Furthermore, the circularity coefficient of the inorganic oxide particles A is 0.900 to 1.000. When the circularity coefficient of the inorganic oxide particles A is within this range, the toner charge amount can be made uniform and stabilized, the filming can be suppressed as the cleaning effect on the surface of the photosensitive member is enhanced, and the toner fluidity is increased. Effects such as improvement can be obtained. The circularity coefficient of the inorganic oxide particles A is more preferably 0.910 to 1.000.

  In the present invention, the circularity coefficient is an index representing a correlation coefficient with a perfect circle shape. For example, a flow type particle image analyzer (FPIA-3000 manufactured by Sysmex Corporation is used in this embodiment). ) Is used as a 50% value based on the number calculated using

  The surface of the inorganic oxide particle A is subjected to a hydrophobic treatment. As a method of hydrophobizing treatment, a conventionally known hydrophobizing agent is brought into contact with the surface of the inorganic oxide particle A before hydrophobizing treatment, and hydrophobic functional groups and components are brought to the surface of the inorganic oxide particle A. Examples of the method include chemical bonding and adhesion. The hydrophobizing agent for hydrophobizing the inorganic oxide particles A is not particularly limited, and conventionally known ones can be exemplified. Preferred examples of such a hydrophobizing agent include octyltriethoxysilane and polydimethylsiloxane. These hydrophobizing agents can be used alone or in combination of two or more. Commercially available hydrophobized inorganic oxide particles may be used as the inorganic oxide particles A.

  The content of the inorganic oxide particles A in the toner is 2 to 10 parts by mass with respect to 100 parts by mass of the toner base particles. When the content of the inorganic oxide particles A in the toner is within this range, the toner charge amount can be made uniform and stabilized, the filming can be suppressed due to the increased cleaning effect on the surface of the photoreceptor, In addition to the effect of improving fluidity and the like, good fixability of the toner on the recording medium can be obtained. The content of the inorganic oxide particles A in the toner is preferably 2 to 8 parts by mass with respect to 100 parts by mass of the toner base particles, and 2 to 5 parts by mass with respect to 100 parts by mass of the toner base particles. More preferably.

[Inorganic oxide particles B]
The inorganic oxide particles B have a small number average particle diameter among the inorganic oxide particles A and B. The inorganic oxide particles B are mainly present in a state of strongly adhering to the surface of the toner base particles, and it is considered that some of them are embedded in the surface of the toner base particles, and the surface of the toner base particles is uniform. By covering the surface, it is considered that the exposure of the release agent from the surface of the toner base particles is suppressed, and the charging of the toner is stabilized.

  Examples of the inorganic oxide particles B include silica, alumina, titania, zirconia, zinc oxide, chromium oxide, cerium oxide, antimony oxide, tungsten oxide, tin oxide, tellurium oxide, manganese oxide, and boron oxide. Among these, silica can be mentioned preferably. The inorganic oxide particles A can be used alone or in combination of two or more.

  The average primary particle diameter of the inorganic oxide particles B is 5 nm to 50 nm. When the average primary particle diameter of the inorganic oxide particles B is within this range, the inorganic oxide particles B can be strongly adhered to the surface of the toner base particles, and the above-described effect can be obtained. The average primary particle diameter of the inorganic oxide particles B is preferably 5 to 20 nm, and more preferably 10 to 20 nm. The method for calculating the average primary particle diameter is as described above.

  The surface of the inorganic oxide particle B is subjected to a hydrophobic treatment. As a method of hydrophobizing treatment, a conventionally known hydrophobizing agent is brought into contact with the surface of the inorganic oxide particle B before hydrophobizing treatment, and hydrophobic functional groups and components are brought to the surface of the inorganic oxide particle B. Examples of the method include chemical bonding and adhesion. The hydrophobizing agent for hydrophobizing the inorganic oxide particles B is not particularly limited, and conventionally known ones can be exemplified. Preferred examples of such a hydrophobizing agent include dimethyldichlorosilane and hexamethyldisilazane. These hydrophobizing agents can be used alone or in combination of two or more. Commercially available hydrophobized inorganic oxide particles may be used as the inorganic oxide particles B.

  The content of the inorganic oxide particles B in the toner is 0.3 to 5 parts by mass with respect to 100 parts by mass of the toner base particles. When the content of the inorganic oxide particles B in the toner is within this range, it is possible to suppress the release agent from being exposed from the surface of the toner base particles or to stabilize the charging of the toner. The content of the inorganic oxide particles B in the toner is preferably 2 to 5 parts by mass and more preferably 3 to 5 parts by mass with respect to 100 parts by mass of the toner base particles.

  The total content of the inorganic oxide particles A and the inorganic oxide particles B is 2.3 to 12 parts by mass with respect to 100 parts by mass of the toner base particles. When the total content of the inorganic oxide particles A and the inorganic oxide particles B is within this range, the filming is suppressed due to the uniformity and stabilization of the charge amount of the toner and the enhancement of the cleaning effect on the surface of the photoreceptor. In addition, effects such as improved toner fluidity can be obtained. In particular, since the toner charge amount is closely related to the toner consumption amount at the time of printing, by optimizing this, the toner consumption amount at the time of printing can be made appropriate. The total content of the inorganic oxide particles A and the inorganic oxide particles B is preferably 2.3 to 10 parts by mass, more preferably 3 to 8 parts by mass with respect to 100 parts by mass of the toner base particles. .

[Toner Preparation]
The toner is prepared through an external addition process in which the external additive is mixed with toner base particles. At that time, other components may be appropriately added in order to improve various characteristics of the toner.

  Examples of the mixing device used for mixing the toner base particles and the external additive include a Henschel mixer and a super mixer. The mixing apparatus is not limited to these, and any mixing apparatus can be used as long as the apparatus can mix powder.

  According to the toner of the present invention, the toner charge amount is made uniform and stabilized, thereby suppressing image smearing of printed matter, toner scattering in the apparatus, and excessive toner consumption. Can do. Further, according to the toner of the present invention, filming on the surface of the photoreceptor is suppressed by the action of the inorganic oxide particles A added as an external additive, and the toner has good fixability on the recording medium. Can be obtained.

<Method for producing toner for developing electrostatic image>
A method for producing an electrostatic charge image developing toner containing each of the above components is also one aspect of the present invention. This production method contains a binder resin, a colorant, a release agent having a melting temperature in a differential scanning calorimeter of 60 ° C. to 75 ° C., and a charge control agent, and the release agent is 3 to 12% by mass. A kneading step of melt kneading a mixture to obtain a kneaded product, a pulverizing and classifying step of pulverizing and classifying the kneaded product to obtain toner base particles, and an average primary particle diameter of 100 nm to 200 nm with respect to the toner base particles. Hydrophobizing inorganic fine particles A having a circularity coefficient of 0.900 to 1.000 with 2 to 10 parts by weight and an average primary particle diameter of 5 to 50 nm with respect to 100 parts by weight of the toner base particles And an external addition step in which 0.3 to 5 parts by mass of the treated inorganic fine particles B are added to 100 parts by mass of the toner base particles and mixed. Since each of these steps has already been described, description thereof is omitted here.

  Hereinafter, the toner for developing an electrostatic charge image of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the following description, unless otherwise specified, “%” means “mass%” and “part” means “part by mass”.

[Preparation of toner base particles A to H]
Toner base particle A (containing 5 parts by weight of a release agent (melting temperature 68 ° C.) in 100 parts by weight of toner base particles)
85 parts by mass of a commercially available polyester resin for non-magnetic color toner (trade name: FC1588, manufactured by Mitsubishi Rayon Co., Ltd.) as a binder, and 8 parts by mass of a cyan colorant (Pigment Blue 15: 3) as a colorant; 2 parts by mass of a zinc alkylsalicylate compound (trade name: Bontron E-84, manufactured by Orient Chemical Co., Ltd.) as a charge control agent, and paraffin wax A (trade name: HNP-11, melting temperature 68 ° C., as a release agent) 5 parts by mass of Nippon Seiwa Co., Ltd.) were mixed using a Henschel mixer and then melt-kneaded using a twin screw extruder. The obtained kneaded material is melted, coarsely pulverized with a funnel plex, then finely pulverized with a jet mill, classified using an air classifier, and negatively charged toner base particles having a number average particle size of 6.5 μm. A was obtained. In addition, the said melting temperature about a mold release agent is calculated | required from the melting peak temperature in a differential scanning calorimeter (hereinafter the same). The number average particle diameter was calculated using the same method as the method for calculating the average primary particle diameter described above.

Toner base particle B (containing 5 parts by weight of a release agent (melting temperature 75 ° C.) in 100 parts by weight of toner base particles)
The toner base particle B is the same as the toner base particle A except that 5 parts by weight of paraffin wax B (trade name: HNP-9, manufactured by Nippon Seiwa Co., Ltd., melting temperature: 75 ° C.) is used as a release agent. Got.

Toner base particle C (containing 12 parts by weight of release agent (melting temperature 68 ° C.) in 100 parts by weight of toner base particles)
Toner base particles C were obtained in the same manner as toner base particles A, except that the amount of polyester resin added was 78 parts by weight and 12 parts by weight of paraffin wax A (melting temperature 68 ° C.) was used as a release agent. .

Toner base particle D (containing 3 parts by weight of a release agent (melting temperature 68 ° C.) in 100 parts by weight of toner base particles)
Toner base particles D were obtained in the same manner as toner base particles A, except that the amount of polyester resin added was 87 parts by weight, and 3 parts by weight of paraffin wax A (melting temperature 68 ° C.) was used as a release agent. .

Toner base particle E (containing 3 parts by weight of a release agent (melting temperature 56 ° C.) in 100 parts by weight of toner base particles)
Toner except that the amount of polyester resin added was 87 parts by mass and 3 parts by mass of paraffin wax C (trade name: Paraffin Wax-130, manufactured by Nippon Seiwa Co., Ltd., melting temperature 56 ° C.) was used as a release agent. Toner base particles E were obtained in the same procedure as base particles A.

Toner base particle F (containing 100 parts by weight of toner base particle, 3 parts by weight of release agent (melting temperature 77 ° C.))
The amount of the polyester resin added was 87 parts by mass, and the toner base was used except that 3 parts by mass of paraffin wax D (trade name: HNP-51, manufactured by Nippon Seiwa Co., Ltd., melting temperature 77 ° C.) was used as the release agent. Toner base particles F were obtained in the same procedure as for particles A.

Toner base particle G (contains 2.8 parts by weight of release agent (melting temperature 68 ° C.) in 100 parts by weight of toner base particles)
The toner base particles are the same as the toner base particles A except that the amount of the polyester resin added is 87.2 parts by weight and 2.8 parts by weight of paraffin wax A (melting temperature 68 ° C.) is used as the release agent. G was obtained.

Toner base particle H (containing 16 parts by weight of release agent (melting temperature 68 ° C.) in 100 parts by weight of toner base particles)
Toner base particles H were obtained in the same procedure as toner base particles A, except that the amount of polyester resin added was 74 parts by weight and 16 parts by weight of paraffin wax A (melting temperature 68 ° C.) was used as a release agent. .

[Toner Preparation]
To the toner base particles A to H, inorganic fine particles A and inorganic fine particles B are added as external additives in the blending amounts shown in Tables 1 to 4, and then these are added by a Henschel mixer (circumferential speed 40 m / s) at 20. The toners of Examples 1 to 12 and Comparative Examples 1 to 12 were obtained by mixing for a minute (processed product temperature: 10 to 40 ° C.). In addition, the compounding quantity shown to Tables 1-4 is a mass part. In Tables 1 to 4, “particle diameter” is an average primary particle diameter, “circularity” is a circularity coefficient determined using FPIA-3000 manufactured by Sysmex Corporation, and “inorganic fine particles A + B” are The total blending amount (parts by mass) of the inorganic fine particles A and B. “Melting agent melting point” and “release agent addition amount” are respectively the melting point of the releasing agent contained in the toner base particles and 100 parts by weight of the toner base particles. It is a mass part of the mold release agent added with respect to.

  Further, in Tables 1 to 4, inorganic fine particles A are silica particles that have been hydrophobized with octyltriethoxysilane, and have the following average primary particle diameter and circularity coefficient, and the inorganic fine particles B are: Silica particles hydrophobized with dimethyldichlorosilane and having the following average primary particle size.

Inorganic fine particles A
A: Average primary particle diameter 100 nm, circularity coefficient 0.920
B: Average primary particle size 200 nm, circularity coefficient 0.910
C: Average primary particle size 90 nm, circularity coefficient 0.900
D: Average primary particle size 300 nm, circularity coefficient 0.910
E: Average primary particle size 100 nm, circularity coefficient 0.885

Inorganic fine particle B
To: Average primary particle size 20nm
G: Average primary particle size 5nm
H: Average primary particle size 50nm
Re: Average primary particle size 80nm

[Filming evaluation]
After printing 25,000 sheets of a 5% printing rate chart in an environment of a temperature of 25 ° C. and a humidity of 50%, using a non-magnetic two-component negative developing A3 page printer (printing speed: 35 sheets / A4 / min) The state of filming on the surface of the photoreceptor was observed. The filming state at that time was evaluated according to the following evaluation criteria, and the results are shown in Tables 1 to 4.
◎: No filming is observed. ○: Filming is slightly observed. △: Filming is observed in a region less than about half of the area of the photoconductor. ×: More than about half of the area of the photoconductor. Filming was observed in the area

[Evaluation of image contamination]
After printing 25,000 sheets under the above conditions, the fog state of the printed material was visually evaluated. The state of occurrence of dirt at that time was evaluated according to the following evaluation criteria, and the results are shown in Tables 1 to 4.
◎: Dirt is not visually discerned, and is within 10 per 9 mm ² with a 25 × magnifier. ○: Dirt is not visually discerned, and 11 or more per 9 mm ² with a 25 × magnifier. Level ×: Level at which dirt can be easily identified visually

[Evaluation of change in charge amount]
When 25,000 sheets were printed under the above conditions, the toner charge amount of the developing device was evaluated with a Q / M meter every 2,000 sheets printed. Changes in charge amount (Q / M) at that time were evaluated according to the following evaluation criteria, and Tables 1 to 4 show the results.
A: Charge amount change from 2,000 sheets to 24,000 sheets is within 20%. B: Charge amount change from 2,000 sheets to 24,000 sheets is more than 20% and within 50%. Δ: 2 The change in charge amount from 4,000 to 24,000 sheets is more than 50% and within 100%. X: The change in charge amount from 2,000 to 24,000 sheets is more than 100%

[Evaluation of consumption stability]
When 25,000 sheets were printed under the above conditions, the amount of decrease in toner for every 1,000 sheets was examined. Based on the results, the stability of toner consumption change was evaluated according to the following evaluation criteria, and the results are shown in Tables 1 to 4.
A: Change in toner consumption per 1,000 sheets up to 25,000 sheets is within 20%. ○: Change in toner consumption per 1,000 sheets up to 25,000 sheets is more than 20% and within 50%. Yes: Change in toner consumption for every 1,000 sheets up to 25,000 sheets is more than 50% and within 100% ×: Change in toner consumption for every 1,000 sheets up to 25,000 sheets exceeds 100% Is

[Evaluation of toner scattering]
After printing 25,000 sheets under the above conditions, the scattering state of the toner inside the developing machine was visually evaluated. The evaluation criteria in that case are as follows, and the results are shown in Tables 1 to 4.
◎: No contamination due to toner scattering inside the developing machine ○: Contamination due to toner scattering inside the developing machine was recognized, but at a level that does not cause any problem in actual use △: Toner inside the developing machine Contamination due to scattering is recognized, and the toner is scattered on the printed matter. ×: Remarkable contamination is observed inside the developing machine.

[Evaluation of fixability]
A solid image was printed, and the surface of the printed matter was rubbed 10 times with a Gakushin type friction fastness tester (load 500 g, application paper: high-quality paper). The image density before and after rubbing was measured with an optical densitometer, and (image density after rubbing / image density before rubbing) × 100 was calculated as a fixing ratio. The fixing rate at that time was evaluated according to the following evaluation criteria, and Tables 1 to 4 show the results.
A: Fixing rate is 90% or more B: Fixing rate is 80% or more and less than 90% B: Fixing rate is 70% or more and less than 80% X: Fixing rate is less than 70%

  As shown in Tables 1 to 4, according to the toner of the present invention, the filming resistance, image stain resistance, charge amount stability, toner consumption stability, toner scattering resistance and fixability are good. It is understood that results are obtained. In particular, when Examples 1 and 2 and Comparative Examples 2, 3 and 4 are compared, by using inorganic fine particles A having an average primary particle diameter of 100 to 200 nm and a circularity coefficient of 0.900 to 1.000, anti-fill resistance It can be seen that there is a marked improvement in mining properties and image stain resistance. Further, when Examples 1, 4 and 5 and Comparative Example 11 are compared, it can be seen that the use of inorganic fine particles B having an average primary particle diameter of 5 nm to 50 nm results in good charge amount stability. And when comparing the whole of each example and each comparative example, by using two kinds of inorganic fine particles having a predetermined number average particle diameter as external additives within the range of the addition amount defined in the present invention, respectively. It can be understood that, while satisfactory toners can be obtained in all the characteristics, the lack of any of these conditions results in a lack of performance balance as a toner. From these results, the usefulness of the toner of the present invention is shown.

Claims (8)

Comprising toner base particles containing a binder resin, a colorant, a release agent and a charge control agent, and an external additive,
As the external additive, hydrophobic treated inorganic oxide particles A having an average primary particle size of 100 nm to 200 nm and a circularity coefficient of 0.900 to 1.000, and an average primary particle size of 5 nm to 50 nm Inorganic oxide particles B,
The content of the inorganic oxide particles A is 2 to 10 parts by mass with respect to 100 parts by mass of the toner base particles, and the content of the inorganic oxide particles B is 0.3 to 5 with respect to 100 parts by mass of the toner base particles. The total content of the inorganic oxide particles A and B is 2.3 to 12 parts by mass with respect to 100 parts by mass of the toner base particles,
A toner for developing an electrostatic charge image, wherein the releasing agent has a melting temperature of 60 ° C. to 75 ° C. in a differential scanning calorimeter and is contained in 3 to 12 parts by mass in 100 parts by mass of toner base particles.   The toner for developing an electrostatic charge image according to claim 1, wherein the inorganic oxide particles B have an average primary particle diameter of 5 nm to 20 nm.   3. The electrostatic charge image developing toner according to claim 1, wherein the total content of the inorganic oxide particles A and B is 2.3 to 10 parts by mass with respect to 100 parts by mass of the toner base particles.   The toner for forming an electrostatic charge image according to claim 1, wherein the inorganic oxide particles A and B are silica.   The electrostatic image developing toner according to any one of claims 1 to 4, wherein the inorganic oxide particles A are those subjected to a hydrophobic treatment with octyltriethoxysilane or polydimethylsiloxane.   The electrostatic image developing toner according to claim 1, wherein the inorganic oxide particles B have been subjected to a hydrophobic treatment with dimethyldichlorosilane or hexamethyldisilazane.   The toner base particles have a volume median particle diameter D50 of 4.5 μm to 8.0 μm, and the number% of toner base particles having a particle diameter of 4.0 μm or less with respect to the total number of toner base particles is 35% or less. The electrostatic charge image developing toner according to claim 1. Melting and kneading a mixture containing a binder resin, a colorant, a release agent having a melting temperature in a differential scanning calorimeter of 60 ° C. to 75 ° C., and a charge control agent, wherein the release agent is 3 to 12% by mass A kneading step to obtain a kneaded product,
A pulverization and classification step of pulverizing and classifying the kneaded product to obtain toner mother particles;
Hydrophobized inorganic fine particles A having an average primary particle diameter of 100 nm to 200 nm and a circularity coefficient of 0.900 to 1.000 with respect to 100 parts by mass of the toner base particles are 2 to 100 parts by weight of the toner base particles. And 10 parts by mass, and an external addition step of adding 0.3 to 5 parts by mass of the hydrophobic inorganic fine particles B having an average primary particle size of 5 nm to 50 nm with respect to 100 parts by mass of the toner base particles, and mixing the mixture. And a method for producing a toner for developing an electrostatic charge image.