JP5499607B2 - Toner for developing electrostatic image and method for producing toner - Google Patents

Description

  The present invention relates to providing a toner for developing an electrostatic image having excellent image quality and a method for producing the same, while suppressing the dust generated at the time of fixing in a low-temperature fixing toner and securing fixing properties and blocking resistance.

  Toner for electrostatic image development that has been widely used in electrophotography in the past is a binder resin such as a styrene / acrylate copolymer or polyester, a colorant such as carbon black or a pigment, and a charge as necessary. It has been produced by melting and kneading a mixture containing a control agent and a magnetic substance with an extruder, followed by pulverization and classification. However, the conventional pulverized toner obtained by such a kneading / pulverization method has a limit in controlling the particle size of the toner, and can substantially produce a toner having an average particle size of 10 μm or less, particularly 8 μm or less with a high yield. It is difficult and cannot be said to be sufficient to achieve the high resolution required for electrophotography.

  Further, in order to achieve low-temperature fixability, a method of blending a wax having a low softening point into the toner during kneading has been proposed, but in the kneading / pulverization method, blending of about 5% is the limit, A toner having sufficient low-temperature fixing performance could not be obtained. In addition, when the flakes obtained after melt-kneading are mechanically pulverized into a toner, the yield is poor and the particle size distribution is wide. This tendency is particularly remarkable when trying to obtain a toner having a small particle diameter.

In recent years, as a method for improving the problems of these kneading / pulverization methods, (a) a toner monomer particle is obtained by suspending and dispersing a polymerizable monomer, a polymerization initiator, a colorant and the like in an aqueous medium and then polymerizing. (B) A polymer primary obtained by emulsifying a polymerizable monomer in an aqueous medium containing a polymerization initiator, an emulsifier, and the like, and polymerizing the polymerizable monomer with stirring. An emulsion polymerization aggregation method in which toner base particles are produced by aggregating and ripening the polymer primary particles by adding a colorant or the like to a particle dispersion; (c) dissolving a polymer, a colorant, etc. in a solvent in advance; There has been proposed a solution suspension method or the like for producing toner mother particles by dispersing a dispersed solution dispersion (solution dispersion of toner composition) in an aqueous medium and removing the solvent by heating or reducing the pressure. Yes.
When these wet methods are used, it is easier to control the dispersion of the raw materials than in the kneading / pulverization method, and a toner having a small particle size and a narrow particle size distribution can be obtained. be able to.
In particular, the emulsion polymerization aggregation method is not only suitable for obtaining a toner having a small particle size or a narrow particle size distribution, but also has an advantage that the toner shape can be easily controlled.

  With the recent spread of copiers, printers, etc., in addition to the demand for further improvement in image quality, a toner that is particularly excellent in high-speed printing and low-energy fixability has been desired, and the low-temperature fixability of the toner has been increased. Improvements are being attempted. At the same time, environmental standards centered on Europe have been established to deal with the impact on the human body in the office environment, and countermeasures are becoming essential in electrophotographic fixing systems.

In particular, in recent years, it has become essential to obtain the most stringent “Blue Angel” certification. In electrophotographic fixing systems, substances that are generated during high-temperature fixing and dissipated outside the device, specifically sublimation. It is required to reduce the dust and organic volatile substances caused by substances to be less than or equal to the regulation values defined in ECMA-328 / RAL_UZ122. Also in Japan, the standard value of RAL_UZ122 has been adopted as it is since the re-revision in 2008 as the Eco Mark certification standard for copiers and multifunction machines, and it is required to comply with these standards. Yes.

  For the purpose of fixing toner at low temperature, low melting point wax is used (Patent Documents 1 and 2). However, since the low melting point wax dissolves at a low temperature and easily sublimates, it becomes a causative substance of dust and it is difficult to achieve reduction of the sublimation substance.

  On the other hand, although it is possible to reduce sublimation substances by using a wax having a high melting point, low-temperature fixability and glossiness are required as toner performance, and simply selecting a high melting point wax These toner performances are significantly impaired.

  In other words, environmental safety and toner performance are in a trade-off relationship, and no one that can meet both requirements has been provided.

Japanese Patent Laid-Open No. 2001-42564 JP 2004-163612 A

  An object of the present invention is to provide a toner for developing an electrostatic image having excellent image quality and a method for producing the same, while suppressing the dust generated at the time of fixing in a low-temperature fixing toner and ensuring fixing property and blocking resistance. .

  The present inventor has repeatedly studied to solve the above-mentioned problems, and uses a saturated hydrocarbon wax containing an appropriate amount of branched and cyclic substances in the wax, and that the problem can be solved by using a polyglycerin fatty acid ester there. I found it. The present invention is based on this finding, and the gist of the present invention is as follows.

(1) In a toner containing at least a polyglycerin fatty acid ester, a binder resin, and a hydrocarbon wax, the wax has a component having 40 or more carbon atoms in 80% or more of the total amount of the hydrocarbon wax and having 40 or more carbon atoms. A toner for developing an electrostatic image, wherein a non-normal component of the hydrocarbon is 18% or more and 40% or less of the total amount of the hydrocarbon wax.
(2) The electrostatic image developing toner according to (1), wherein the polyglycerin fatty acid ester is contained in an amount of 0.01 to 10 parts by mass in 100 parts by mass of the toner.
(3) The electrostatic image developing toner according to (1) or (2), wherein the acid value of the polyglycerol fatty acid ester is 1 mg-KOH / g or more.
(4) The volume median diameter (Dv50) is 4 μm or more and 7 μm or less, and the particle size distribution Dv50 / Dn50 expressed by the ratio of the volume median diameter to the number median diameter (Dn50) is 1.1 or less. The toner for developing an electrostatic charge image according to any one of (1) to (3) above, wherein
(5) The toner for developing an electrostatic charge image according to any one of (1) to (4), which is produced by a polymerization method.
(6) The electrostatic image development according to any one of (1) to (5) above, wherein a polyglycerin fatty acid ester is added in the step of producing a wax dispersion by dispersing a hydrocarbon wax in a dispersion medium. Toner manufacturing method.
(7) The method for producing an electrostatic charge image developing toner as described in (6) above, wherein the volume median diameter of the wax dispersion in the wax dispersion is 0.01 μm or more and 1 μm or less.

  According to the present invention, it is possible to provide a toner for developing an electrostatic image having excellent image quality and a method for producing the same, while suppressing the dust generated at the time of fixing in a low-temperature fixing toner, ensuring fixing property and blocking resistance. .

  The toner of the present invention contains at least a polyglyceric acid fatty acid ester, a binder resin, a colorant, and a wax, and may contain a charge control agent, an external additive, and the like as necessary.

  Most of the causative substances of dust, which is generated at the time of fixing at high temperature and is diffused outside the apparatus, are wax components contained in the toner. This is caused not only by the wax in the toner being dissolved and exerting a releasing action by a high-temperature fixing device that is passed through when the toner transferred onto the paper is fixed, but also by sublimation of a part thereof. Since dust is the result of the physical sublimation phenomenon of the wax component, a method for suppressing the sublimation of the wax itself is required.

  When non-polar wax is used as the toner wax, a high release effect is obtained without being blended with the binder resin, and because it is highly hydrophobic, it is advantageous in terms of environmental resistance, but because the intermolecular force is low. It is difficult to suppress dust. If a method of increasing the molecular weight and suppressing dust is used, the melting point is increased and low temperature fixing becomes a problem. In the wet method, since non-polar wax is handled in an aqueous medium, sufficient dispersion stability is required, and the wax incorporated during the production is uniformly dispersed in the toner and is sufficiently in the resin. It must also be wrapped. Nonpolar waxes are not preferred because they tend to improve toner performance but are difficult to produce.

On the other hand, there is a method of suppressing sublimation by increasing the intermolecular force between wax molecules or between a wax and a resin component. A typical example is an ester wax having a polar group, but these have low sublimation even at a relatively low melting point, and are useful for suppressing dust without deteriorating fixing performance. However, the familiarity with the resin and the addition of polar groups suppress the wax leakage during granulation, making it relatively easy to manufacture. Since the storage stability is seriously damaged, a problem is easily caused in the toner performance itself, which is not preferable.
Based on these findings, the present invention provides a toner for developing an electrostatic image having excellent image quality while ensuring fixability and anti-blocking property while suppressing dust generated during fixing in a low-temperature fixing toner.

The wax used in the toner of the present invention is a hydrocarbon, and the component having 40 or more carbon atoms is 80% or more of the total amount of the hydrocarbon wax, and among these, non-normal bodies such as iso forms and cyclic bodies are carbonized. 18% or more and 40% or less of the total amount of hydrogen wax. When the number of components having a carbon number of 40 or more in the wax is smaller than that of the present invention, a component having a low molecular weight in the molecular weight distribution of the wax is easily sublimated, which is not preferable because the amount of sublimation generated from the toner increases as a dust component. The upper limit of the carbon number of the wax is not particularly limited, but 95% or less is preferable and 90% or less is more preferable in order to achieve low-temperature fixability of the toner, although it depends on the amount of non-normal components. When the component having 40 or more carbon atoms is 100%, even if the non-normal component is within the range of the present invention, the fixing lower limit temperature of the toner to be obtained is increased, so that the fixing temperature range becomes high, and energy saving and high-speed printing performance are achieved. It may decrease.
Further, in the wax of the present invention, in order to further suppress the generation of dust, the component having 30 or more carbon atoms is preferably 90% or more, more preferably 95% or more, and may be 100% in the total amount of the hydrocarbon wax. .

In the present invention, among the components having a carbon number of 40 or more in the wax, it is essential that the non-normal body is 18% or more, more preferably 20% or more, of the total amount of the hydrocarbon wax. In the present invention, from the viewpoint of dust suppression, it is essential that the component having 40 or more carbon atoms is 80% or more. However, increasing the number of carbon atoms means that the molecular weight is high, and only the normal body. Increases the crystallinity and increases the melt viscosity. Therefore, if the non-normal ratio is too small, the melting point of the wax is increased, the melt viscosity of the toner is increased, the lower fixing temperature of the toner is increased, and the fixing temperature range is moved to the higher temperature side, thereby saving energy and increasing the speed. Printing performance may be degraded. Of the components having a carbon number of 40 or more in the wax, it is essential that the non-normal body is 40% or less, preferably 36% or less, and more preferably 33% or less. When the ratio of the non-normal body is too large, the wax oozes out during granulation and tends to deteriorate the fluidity of the toner. In addition, since the fluidity tends to deteriorate as the particle size of the toner decreases, the wax of the present invention is particularly suitable for a small particle size toner having a volume average particle size of 4 to 7 μm.

  Since the wax of the present invention does not contain a polar group, it has strong hydrophobicity and low affinity with a resin, so that it is difficult to disperse in water and in toner, and the dispersion state stability is also low. Therefore, by combining the polyglycerin fatty acid ester of the present invention, the dispersion stability of the wax during the production process and in water is improved, and the dispersibility of the wax in the toner is improved.

  The carbon number of the wax can be measured by high temperature gas chromatography with FID (high temperature GC) and mass spectrometer (MS). The linear carbon number is determined by measuring the peak and the carbon number of each chromatogram in advance using a linear polyethylene wax as a standard. The molecular weight of is determined by mass identification of each carbon component separated by high temperature GC using MS directly connected. Since peaks with the same molecular weight appear at different positions from the peak derived from straight-chain carbon, they are identified as non-normal components such as isoforms / cyclic bodies, and normal and non-normal forms are identified from the area of each peak. The composition ratio can be calculated.

  Examples of waxes that satisfy this condition include graft polymer waxes, star polymer waxes, microcrystalline waxes, and the like that contain a large amount of hydrocarbon components having a branched or cyclic structure. A microcrystalline wax that satisfies the requirements such as the number of carbon atoms of the invention is preferred.

The wax of the present invention may be one kind, or a plurality of waxes having different composition ratios may be mixed so as to satisfy the requirements of the present invention.
As the wax to be mixed, known waxes can be arbitrarily used. Specifically, hydrocarbon waxes such as paraffin wax and Fischer-Tropsch wax are preferable in order to achieve both toner characteristics and dust suppression.

  In the present invention, the amount of the wax is preferably 1 part by mass or more per 100 parts by mass of the toner, more preferably 2 parts by mass or more, and further preferably 5 parts by mass or more. Moreover, it is preferable that it is 40 mass parts or less, More preferably, it is 35 mass parts or less, More preferably, it is 30 mass parts or less. When the wax content in the toner is less than the above range, the performance such as high temperature offset property may not be sufficient, and when it exceeds the above range, the blocking resistance is insufficient or the wax leaks from the toner. May contaminate the device.

Polyglycerin fatty acid ester is widely used as a highly safe emulsifier for food addition and emulsification of functional fats and oils. Hydrophilic properties can be obtained by combining the degree of polyglycerin condensation with the type of fatty acid and the degree of esterification. It has the feature that it can express a wide range of emulsification performance from hydrophilicity to lipophilicity.
In the present invention, when a toner is produced by a polymerization method such as a suspension polymerization method, an emulsion polymerization aggregation method, or a dissolution suspension method by using a polyglycerin fatty acid ester, the wax particles and other fine particles in an aqueous solvent are used. The stability of the toner and the dispersibility of the wax in the final toner can be improved. Since the wax contains a long-chain hydrocarbon group as a crystalline part, it is highly hydrophobic and difficult to disperse in an aqueous solvent or a polar resin, but the polyglycerol fatty acid ester of the present invention is an aqueous solvent and a polar one. Dispersibility is improved by being present at the interface with the resin. In particular, since the wax of the present invention does not contain a polar group, it has a strong hydrophobicity and tends to be inferior in dispersibility in water and in toner. Therefore, the present invention can provide a particularly great effect.

The polyglycerol fatty acid ester used in the present invention preferably has a hydroxyl value of 1.0 mg-KOH / g or more. 5 mg-KOH / g or more is more preferable, 10 mg-KOH / g or more is more preferable, 20 mg-KOH / g or more is more preferable, and 25 mg-KOH / g or more is particularly preferable. The upper limit is preferably 500 mg-KOH / g or less, more preferably 300 mg-KOH / g or less, and further preferably 150 mg-KOH / g or less.
The hydroxyl value refers to the number of mg of potassium hydroxide required to neutralize acetic acid necessary for acetylating a free hydroxyl group contained in 1 g obtained by a conventional method. If the hydroxyl value is too low, the ability to control the dispersion / aggregation balance of the raw material, intermediate product and final toner base particles in an aqueous solvent tends to be poor throughout the entire process from raw material storage to particle production. On the other hand, if the hydroxyl value is too high, the hydrophilicity tends to be affected by the humidity in the air, and the environmental resistance of the toner tends to be lost. Also, in the manufacturing process, the affinity to the manufacturing container and the inner wall surface of the pipe is increased and adhesion occurs, which may affect the dispersion / aggregation balance of the particles, making it difficult to obtain a toner with stable performance. .

The polyglycerin fatty acid ester of the present invention preferably has an acid value of 1 mg-KOH / g or more, and more preferably 20 mg-KOH / g or less. Acid value is 1
It means the number of mg of potassium hydroxide required to neutralize the acidic component contained in g. When the acid value is within the above range, high particle control ability in an aqueous solvent can be obtained.

  The polyglycerol fatty acid ester of the present invention is at least one glycerol multimeric component such as diglycerol, triglycerol, tetraglycerol, hexaglycerol, decaglycerol, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid. An ester compound produced by a reaction with at least one of higher saturated and unsaturated fatty acid components having 12 to 30 carbon atoms such as oleic acid and erucic acid, specifically, decaglycerin decabehenate, deca Examples include glycerin heptearate, decaglycerin tetrabehenate, octaglycerin octapalinate, octaglycerin tetrabehenate, hexaglycerin hexabehenate, tetraglycerin pentastearate, tetraglycerin tetrabehenate, etc. It is, be one kind or may be used two or more.

Polyglycerin fatty acid ester is effective regardless of which step in the toner production process is added. As a specific process, in the case of a suspension polymerization method, a process for producing a wax dispersion, a binder resin monomer Examples include a step of dissolving the wax, a step of suspending the monomer solution in which the wax is dissolved, and the emulsion polymerization method includes a step of producing a wax dispersion and a step of aggregating the binder resin fine particles and the wax. If it is a melt suspension polymerization method, the process of manufacturing a wax dispersion, the process of melt | dissolving binder resin, wax, etc. in a solvent, etc. are mentioned. In particular, in the polymerization method, the greatest effect is exhibited when added in the step of producing a wax dispersion.
The wax dispersion manufacturing process refers to a process of dispersing wax in a dispersion medium. The dispersion medium is not particularly limited, and examples thereof include an aqueous medium and an organic solvent. Examples of the aqueous medium include water such as distilled water, deionized water, and demineralized water, alcohols, acetate esters, ketones, and mixtures thereof. These may be used alone or in combination of two or more.

In the present invention, the volume median diameter of the wax dispersion in the wax dispersion is preferably 0.01 μm or more. Further, it is preferably 1.0 μm or less, more preferably 0.5 μm or less, and particularly preferably 0.4 μm or less. If the volume average particle size of the dispersion is too small, in the case of the emulsion polymerization aggregation method, the cohesive force is too strong and the aggregation tends to run away, and if it is too large, the toner having a small particle size contains sufficient wax. There is a tendency not to.
In the present invention, as a method of blending wax in the polymerization method, it is preferable to disperse the wax in water in advance. In the emulsion polymerization aggregation method, it is preferable to add the wax dispersion dispersed in the above average diameter range during emulsion polymerization or in the aggregation step.
In order to disperse the wax with a suitable dispersed particle size in the toner, it is preferable to use so-called seed polymerization in which the wax is added as a seed during emulsion polymerization. By adding as a seed, the wax is finely and uniformly dispersed in the toner, so that deterioration of the chargeability and heat resistance of the toner can be suppressed.

  The content of the polyglycerol fatty acid ester of the present invention is preferably 0.01 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the toner. More preferably, it is 5 mass parts or less, More preferably, it is 4.5 mass parts or less, Most preferably, it is 4 mass parts or less. If the content is too low, sufficient effects may not be obtained. If the content is too high, it becomes more susceptible to humidity in the air due to the increase in hydrophilicity, and the environment resistance such as toner solidification and storage stability. May cause loss of sex. Also, it tends to be difficult to obtain a toner with stable performance, such as significantly increasing the viscosity of the emulsion and dispersion formed in the manufacturing process.

The polyglycerin fatty acid ester of the present invention can improve the stability of wax particles and other particles in the toner production process in water and the dispersibility of the final toner wax.
By improving the dispersibility of the wax, exposure of the wax to the toner surface and release from the toner are suppressed. The wax or free wax exposed on the toner surface may contaminate various parts of the image forming apparatus, resulting in image quality deterioration such as fogging, PC contamination, dirt, afterimage (ghost), blurring (solid followability), and cleaning properties. The toner during storage is blocked, or the external additive on the toner surface is gradually buried in the toner, which tends to cause deterioration of toner fluidity, storage stability, chargeability, and the like.

  The method for producing the toner of the present invention is not particularly limited, but a wet method is preferable. Examples of the wet method include a polymerization method such as a suspension polymerization method, an emulsion polymerization aggregation method, and a dissolution suspension method, and are not particularly limited.

  In the present invention, the production method of the suspension polymerization method includes a coloring agent, a polymerization initiator, and, if necessary, a wax, a polar resin, a charge control agent and a crosslinking agent in the binder resin monomer described later. An additive is added to prepare a monomer composition that is uniformly dissolved or dispersed. This monomer composition is dispersed in an aqueous medium containing a dispersion stabilizer and the like. Preferably, granulation is performed by adjusting the stirring speed and time so that the droplets of the monomer composition have a desired toner particle size. Thereafter, toner mother particles can be obtained by performing polymerization by stirring to such an extent that the particle state is maintained by the action of the dispersion stabilizer and the precipitation of the particles is prevented.

  As a production method of the emulsion polymerization aggregation method, polymer primary particles of a binder resin monomer obtained by emulsion polymerization, a colorant dispersion, a wax dispersion, etc. are prepared, and these are dispersed in an aqueous medium. By performing heating or the like, toner mother particles can be obtained through an aggregating step and an aging step.

  In the present invention, as the binder resin contained in the toner, resins conventionally used as the binder resin for toner can be appropriately used. For example, as a monomer, a polymerizable monomer having an acidic group (hereinafter sometimes simply referred to as an acidic monomer), a polymerizable monomer having a basic group (hereinafter simply referred to as a basic monomer) A polymerizable monomer having no acidic group or basic group (hereinafter, also referred to as other monomer) may be used. it can.

  In the case of the emulsion polymerization aggregation method, in the emulsion polymerization step, the polymerizable monomer is usually polymerized in an aqueous medium in the presence of an emulsifier. At this time, in supplying the polymerizable monomer to the reaction system, The monomers may be added separately or a plurality of types of monomers may be mixed in advance and added simultaneously. The monomer may be added as it is, or may be added as an emulsion mixed and adjusted in advance with water or an emulsifier.

  As the acidic monomer, a polymerizable monomer having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, cinnamic acid, a polymerizable monomer having a sulfonic acid group such as sulfonated styrene, Examples thereof include polymerizable monomers having a sulfonamide group such as vinylbenzenesulfonamide. Examples of the basic monomer include aromatic vinyl compounds having an amino group such as aminostyrene, nitrogen-containing heterocyclic-containing polymerizable monomers such as vinylpyridine and vinylpyrrolidone, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, etc. And (meth) acrylic acid ester having an amino group. These acidic monomers and basic monomers may be used singly or as a mixture of a plurality of types, and may exist as a salt with a counter ion. Among these, it is preferable to use an acidic monomer, more preferably acrylic acid and / or methacrylic acid.

  The total amount of the acidic monomer and the basic monomer in 100 parts by mass of the total polymerizable monomers constituting the binder resin is preferably 0.05 parts by mass or more, more preferably 0.5 parts by mass. As mentioned above, More preferably, it is 1 mass part or more, Preferably it is 10 mass parts or less, More preferably, it is 5 mass parts or less.

  Examples of other polymerizable monomers include styrenes such as styrene, methylstyrene, chlorostyrene, dichlorostyrene, p-tert-butylstyrene, pn-butylstyrene, and pn-nonylstyrene, methyl acrylate, Acrylic esters such as ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n methacrylate -Methacrylic acid esters such as butyl, isobutyl methacrylate, hydroxyethyl methacrylate, 2-ethylhexyl methacrylate, acrylamide, N-propylacrylamide, N, N-dimethylacrylamide, N, N-dipropylacrylic De, N, N-dibutyl acrylamide, and the like, the polymerizable monomer may be used singly, or may be used in combination.

  Furthermore, when the binder resin is a cross-linked resin, a polyfunctional monomer having radical polymerizability is used together with the above polymerizable monomer, for example, divinylbenzene, hexanediol diacrylate, ethylene glycol dimethacrylate, Examples include diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, and diallyl phthalate. It is also possible to use a polymerizable monomer having a reactive group in a pendant group, such as glycidyl methacrylate, methylol acrylamide, acrolein and the like. Among these, radically polymerizable bifunctional polymerizable monomers are preferable, and divinylbenzene and hexanediol diacrylate are particularly preferable. These polyfunctional polymerizable monomers may be used alone or as a mixture of plural kinds.

  In this invention, a well-known polymerization initiator can be used as needed, A polymerization initiator can be used 1 type or in combination of 2 or more types. For example, persulfates such as potassium persulfate, sodium persulfate, ammonium persulfate, and the like, and redox initiators combining these persulfates as a component with a reducing agent such as acidic sodium sulfite, hydrogen peroxide, 4,4 Water-soluble polymerization initiators such as' -azobiscyanovaleric acid, t-butyl hydroperoxide, cumene hydropeoxide, etc., and these water-soluble polymerization initiators as a component combined with a reducing agent such as ferrous salt Redox initiator systems, benzoyl peroxide, 2,2′-azobis-isobutyronitrile, and the like are used. These polymerization initiators may be added to the polymerization system before, simultaneously with the addition of the monomer, or after the addition, and these addition methods may be combined as necessary.

  In the present invention, a known chain transfer agent can be used as necessary. Specific examples of the chain transfer agent include t-dodecyl mercaptan, 2-mercaptoethanol, diisopropyl xanthogen, carbon tetrachloride, trichlorobromomethane, and the like. The chain transfer agent may be used alone or in combination of two or more, and is used in an amount of 0 to 5% by weight based on the polymerizable monomer.

Moreover, in this invention, a well-known suspension stabilizer can be used as needed. Specific examples of the suspension stabilizer include calcium phosphate, magnesium phosphate calcium hydroxide, magnesium hydroxide and the like. These may be used alone or in combination of two or more, and may be used in an amount of 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer.
Both the polymerization initiator and the suspension stabilizer may be added to the polymerization system at any time before, simultaneously with, or after the addition of the polymerizable monomer. You may combine.
In addition, a pH adjuster, a polymerization degree adjuster, an antifoaming agent, and the like can be appropriately added to the reaction system.

  In the present invention, when the binder resin is polymerized by emulsion polymerization, known emulsifiers can be used, but one kind selected from a cationic surfactant, an anionic surfactant and a nonionic surfactant Alternatively, two or more emulsifiers can be used in combination.

  Examples of the cationic surfactant include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide, and examples of the anionic surfactant include And fatty acid soap such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate and the like. Nonionic surfactants include, for example, polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monooleate ether, monodecanoyl sucrose, etc. Is mentioned.

  In this invention, it is preferable that the usage-amount of an emulsifier is used by 0.1 to 10 mass parts with respect to 100 mass parts of polymerizable monomers. In addition, these emulsifiers can be used as protective colloids, for example, one or more of partially or completely saponified polyvinyl alcohols such as polyvinyl alcohol and cellulose derivatives such as hydroxyethyl cellulose.

  In the present invention, the volume average particle size of the polymer primary particles obtained by emulsion polymerization is usually 0.02 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, and usually 1 μm or less, preferably 0. 0.8 μm or less, more preferably 0.5 μm or less. If the particle size is too small, it may be difficult to control the aggregation rate in the aggregation process. If it is too large, the particle size of the toner particles obtained by aggregation tends to be large, and a toner having the target particle size is obtained. May be difficult.

  A known colorant can be arbitrarily used as the colorant of the present invention. Specific examples of colorants include carbon black, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow, rhodamine dyes, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dye, monoazo, Any known dyes and pigments such as disazo dyes and condensed azo dyes can be used alone or in combination. In the case of a full color toner, it is preferable to use benzidine yellow for yellow, monoazo and condensed azo dyes, magenta for quinacridone and monoazo dyes, and cyan for phthalocyanine blue. The colorant is preferably used so as to be 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polymer primary particles.

  The blending of the colorant in the emulsion polymerization aggregation method is usually performed in an aggregation step. A dispersion of polymer primary particles and a dispersion of colorant particles are mixed to form a mixed dispersion, which is then aggregated to form a particle aggregate. The colorant is preferably used in a state of being dispersed in water in the presence of an emulsifier, and the volume average particle diameter of the colorant particles is 0.01 or more, more preferably 0.05 μm or more, and more preferably 3 μm or less. 1 μm.

  In the present invention, when a charge control agent is used, any known one can be used alone or in combination. For example, a quaternary ammonium salt, a basic or electron donating metal as a positive charge control agent. Substances such as metal chelates, metal salts of organic acids, metal-containing dyes, nigrosine dyes, amide group-containing compounds, phenolic compounds, naphthol compounds and their metal salts, urethane bond-containing compounds, Examples include acidic or electron-withdrawing organic substances.

  In addition, when the toner for developing an electrostatic image obtained by the production method of the present invention is used as a toner other than a black toner in a color toner or a full color toner, a charge control agent that is colorless or light in color and does not impair the color tone of the toner is used. It is preferable to use, for example, a quaternary ammonium salt compound as a positively chargeable charge control agent, a metal salt of salicylic acid or an alkylsalicylic acid with chromium, zinc, aluminum, a metal complex as a negatively chargeable charge control agent, Hydroxys such as metal salts of benzylic acid, metal complexes, amide compounds, phenolic compounds, naphthol compounds, phenolamide compounds, 4,4′-methylenebis [2- [N- (4-chlorophenyl) amide] -3-hydroxynaphthalene] Naphthalene compounds are preferred.

  In the present invention, when a charge control agent is contained in the toner using the emulsion polymerization aggregation method, the charge control agent is added together with a polymerizable monomer or the like at the time of emulsion polymerization, or together with the polymer primary particles and the colorant. It can be blended by a method such as adding in the agglomeration step, or adding after the polymer primary particles and the colorant are aggregated to almost the target particle size. Among these, it is preferable to disperse the charge control agent in water using a surfactant and add it to the aggregation step as a dispersion having a volume average particle size of 0.01 μm or more and 3 μm or less.

In the emulsion polymerization aggregation method, the aggregation is usually carried out in a tank equipped with a stirrer, but there are a heating method, a method of adding an electrolyte, and a method of combining them. When polymer primary particles are agglomerated with stirring to obtain particle aggregates of the desired size, the particle size of the particle aggregates is controlled based on the balance between the agglomeration force between the particles and the shearing force due to agitation. However, the cohesive force can be increased by heating or adding an electrolyte.
In the present invention, the electrolyte in the case of performing aggregation by adding an electrolyte may be either an organic salt or an inorganic salt. Specifically, NaCl, KCl, LiCl, Na ₂ SO ₄ , K ₂ SO ₄ , Li ₂ SO ₄ , MgCl ₂ , CaCl ₂ , MgSO ₄ , CaSO ₄ , ZnSO ₄ , Al ₂ (SO ₄ ) ₃ , Fe ₂ (SO ₄ ) ₃ , CH ₃ COONa, C ₆ H ₅ SO ₃ Na, etc. It is done. Of these, inorganic salts having a divalent or higher polyvalent metal cation are preferred.

In the present invention, the amount of electrolyte added varies depending on the type of electrolyte, target particle size, etc., but is preferably 0.05 parts by mass or more, and 0.1 parts by mass with respect to 100 parts by mass of the solid component of the mixed dispersion. Part or more is more preferable. Further, it is preferably 25 parts by mass or less, more preferably 15 parts by mass or less, and particularly preferably 10 parts by mass or less. When the addition amount is too small, the progress of the agglutination reaction is delayed, and there are problems such that fine powder of 1 μm or less remains after the agglomeration reaction or the average particle diameter of the obtained particle aggregate does not reach the target particle diameter. In some cases, if the amount is larger than the above range, rapid aggregation tends to occur and it is difficult to control the particle size, and the obtained aggregated particles may cause problems such as inclusion of coarse powder or irregular shapes. . When the aggregation is performed by adding an electrolyte, the aggregation temperature is 20 ° C. or higher, more preferably 30 ° C. or higher, and 70 ° C. or lower, more preferably 60 ° C. or lower.
The aggregation temperature in the case of performing aggregation only by heating without using an electrolyte is preferably (Tg-20) ° C. or higher, and more preferably (Tg-10) ° C. or higher, where Tg is the glass transition temperature of the polymer primary particles. . Moreover, Tg or less is preferable and (Tg-5) degree C or less is preferable.

  The time required for agglomeration is optimized depending on the shape of the apparatus and the processing scale, but in order for the toner particle size to reach the target particle size, it is usually held at the predetermined temperature for at least 30 minutes. desirable. The temperature rise until reaching the predetermined temperature may be raised at a constant rate, or may be raised stepwise.

  On the surface of the particle aggregate after the above-described aggregation treatment, particles with resin fine particles attached or fixed can be formed as necessary. By attaching or fixing resin fine particles whose properties are controlled to the surface of the particle aggregate, the chargeability and heat resistance of the obtained toner may be improved, and the effects of the present invention can be further enhanced. .

When resin fine particles having a glass transition temperature higher than the glass transition temperature of the polymer primary particles are used as the resin fine particles, it is preferable because blocking resistance can be further improved without impairing fixability. The volume average particle size of the resin fine particles is preferably 0.02 μm or more, and more preferably 0.05 μm or more. Moreover, 1 micrometer or less, Furthermore, 0.6 micrometer or less are preferable. As the resin fine particles, those obtained by emulsion polymerization of monomers similar to the polymerizable monomers used for the above-described polymer primary particles can be used.
The resin fine particles are usually used as a dispersion dispersed in water or a liquid mainly composed of water using a surfactant. However, when a charge control agent is added after the aggregation treatment, charge control is performed on the dispersion containing particle aggregates. It is preferable to add resin fine particles after adding the agent.

  In order to increase the stability of the particle aggregate obtained in the aggregation step, it is preferable to perform fusion in the aggregated particles in the aging step after the aggregation step. The temperature of the ripening step is preferably not less than Tg of the polymer primary particles, more preferably not less than 5 ° C higher than Tg, and preferably not more than 80 ° C higher than Tg, more preferably not less than 50 ° C higher than Tg. It is as follows. The time required for the aging step varies depending on the shape of the target toner, but after reaching the glass transition temperature or higher of the polymer primary particles, it is usually held for 0.1 to 10 hours, preferably 1 to 6 hours. Is desirable.

  In addition, it is preferable to add a surfactant or raise the pH value after the aggregation process, preferably before the aging process or during the aging process. As the surfactant used here, one or more emulsifiers can be selected from the emulsifiers that can be used when producing the polymer primary particles. In particular, the emulsifiers used when producing the polymer primary particles. It is preferable to use the same. Although the addition amount in the case of adding surfactant is not limited, Preferably it is 0.1 mass part or more with respect to 100 mass parts of solid components of a mixed dispersion liquid, More preferably, it is 1 mass part or more, More preferably, it is 3 masses. It is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and still more preferably 10 parts by mass or less. After the aggregation process, before the completion of the ripening process, by adding a surfactant or raising the pH value, it is possible to suppress aggregation of the particle aggregates aggregated in the aggregation process, In some cases, the generation of coarse particles can be suppressed.

  By heat treatment in the aging step, the polymer primary particles in the aggregate are fused and integrated, and the toner particle shape as the aggregate becomes close to a spherical shape. The particle aggregate before the aging step is considered to be an aggregate due to electrostatic or physical aggregation of the polymer primary particles, but after the aging step, the polymer primary particles constituting the particle aggregate are fused to each other. In addition, the shape of the toner particles can be made nearly spherical. According to such an aging process, by controlling the temperature and time of the aging process, the shape of the polymer primary particles is agglomerated, a potato type with advanced fusion, a spherical form with further fusion For example, various shapes of toner can be manufactured according to the purpose.

The toner base particles obtained by the wet method are subjected to a step of filtering and washing the toner base particles from a dispersion containing the toner base particles and a dispersion medium using a centrifuge.
In the step of filtering and washing, for example, the toner base particle collecting property, clogging resistance, cake-forming property, water permeability, and convenience when replacing the filter cloth are required. It is not easy to satisfy these required characteristics at the same time. In particular, toner base particles obtained by a wet method are particles having a small particle size, and it is difficult to satisfy them simultaneously.
Further, in the toner base particle dispersion (slurry) processed in the step of filtering and washing, it is derived not only from the toner base particles but also from raw materials, surfactants and additives used in each manufacturing process. Since impurities such as various by-products and contaminants are present, when effective filtration and washing that appropriately removes these impurities in the filtration and washing process is not performed, the toner of the electrostatic image developing toner finally obtained can be obtained. Performance will be poor. That is, toner obtained from toner base particles from which impurities are not properly removed tends to be inferior in terms of storage stability, and when image formation is performed, the image is fogged. Temperature and humidity changes during image formation Image quality fluctuations due to image density, toner scattering in the image forming apparatus, and a constant quality image when used for a long time cannot be obtained. Become. Therefore, filtration cleaning that can sufficiently remove impurities is desired.
The technique of the present invention realizes filtration and cleaning satisfying each of these required characteristics.

To the toner of the present invention, externally added fine particles can be added as necessary to improve toner fluidity and charge control properties. Examples of such externally added fine particles include various inorganic or organic fine particles. It can be appropriately selected and used.
Inorganic fine particles include silicon carbide, boron carbide, titanium carbide, zirconium carbide, hafnium carbide, vanadium carbide, tantalum carbide, niobium carbide, tungsten carbide, chromium carbide, molybdenum carbide, calcium carbide, and other carbides, boron nitride, titanium nitride. , Various nitrides such as zirconium nitride, various borides such as zirconium boride, various oxides such as titanium oxide, calcium oxide, magnesium oxide, zinc oxide, copper oxide, aluminum oxide, cerium oxide, silica, colloidal silica, titanium Various titanate compounds such as calcium oxide, magnesium titanate and strontium titanate, phosphate compounds such as calcium phosphate, sulfides such as molybdenum disulfide, fluorides such as magnesium fluoride and fluorocarbon, aluminum stearate, stearin Calcium, zinc stearate, can be used various metal soaps such as magnesium stearate, talc, bentonite, various carbon black or conductive carbon black, magnetite, ferrite or the like. As the organic fine particles, fine particles such as styrene resin, acrylic resin, epoxy resin, and melamine resin can be used.

  Among these externally added fine particles, silica, titanium oxide, alumina, zinc oxide, various carbon blacks, conductive carbon blacks, and the like are preferably used. Further, the externally added fine particles are obtained by applying the surface of the inorganic or organic fine particles to a silane coupling agent, a titanate coupling agent, a silicone oil, a modified silicone oil, a silicone varnish, a fluorine silane coupling agent, a fluorine silicone oil, What has been subjected to surface treatment such as hydrophobization with a treating agent such as a coupling agent having an amino group or a quaternary ammonium base can also be used. Two or more kinds of the treatment agents can be used in combination.

The externally added fine particles of the present invention preferably have an average particle size of 0.001 μm or more, more preferably 0.005 μm or more. Moreover, 3 micrometers or less are preferable, More preferably, it is 1 micrometer. Also, a plurality of types having different particle sizes can be blended. The average particle diameter of the externally added fine particles can be determined by observation with an electron microscope.
In addition, the externally added fine particles can be used in combination of two or more different types, can be used in combination with those that have been surface-treated and those that have not been surface-treated, or can be used in combination with those that have been surface-treated differently, A positively chargeable one and a negatively chargeable one can be used in appropriate combination.

The content of the externally added fine particles of the present invention is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, preferably 5 parts by mass or less, more preferably 100 parts by mass of the toner particles. Is 3 parts by mass or less.
Examples of the method for adding the externally added fine particles include a method using a high-speed stirrer such as a Henschel mixer, a method using an apparatus capable of applying a compressive shear stress, and the like.

  Further, inorganic fine powders such as magnetite, ferrite, cerium oxide, strontium titanate, and conductive titania can be added. The amount of these additives used may be appropriately selected depending on the desired performance, and is usually preferably 0.05 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the toner particles.

  The toner for developing an electrostatic charge image of the present invention preferably has a volume median diameter (Dv50) of 7 μm or less, more preferably 6.5 μm or less, and particularly preferably 6 μm or less. Moreover, it is preferable that it is 4 micrometers or more, and it is more preferable that it is 4.5 micrometers or more. If the volume median diameter is too large, it may not be suitable for high-resolution image formation. If it is too small, handling as a powder tends to be difficult.

  The value (Dv50 / Dn50) obtained by dividing the volume median diameter (Dv50) of the present invention by the number median diameter (Dn50) is desirably close to 1.0, preferably 1.1 or less, and preferably 1.09 or less. Further preferred. Since the electrostatic charge image developing toner has a sharper particle size distribution, the chargeability between the particles tends to be uniform. Therefore, the electrostatic charge image developing toner (Dv50 / Dn50) for achieving high image quality and high speed can be obtained. ) Is preferably within the above range. The volume median diameter (Dv50) and the number median diameter (Dn50) are measured and defined by the methods described in the examples.

The shape of the toner for developing an electrostatic image is preferably as close to a sphere as possible, and the average circularity is preferably 0.90 or more, more preferably 0.92 or more, and particularly preferably 0.95 or more. The closer to a sphere, the less the amount of charge is localized in the particles and the developability tends to be uniform. On the other hand, a perfect spherical toner is a toner in the cleaning process on the photoreceptor in electrostatic charge image development. The average circularity is preferably 0.995 or less, and more preferably 0.990 or less. The average circularity is defined as a value obtained by measuring by the method described in the examples and measuring the average circularity.

  The toner for developing an electrostatic charge image obtained by the production method of the present invention is used in any form of a two-component developer using toner particles together with a carrier, or a magnetic or non-magnetic one-component developer not using a carrier. Also good. When used as a two-component developer, the carrier may be a magnetic substance such as iron powder, magnetite powder, ferrite powder or the like, or a known material such as a resin-coated surface or a magnetic carrier. As the coating resin of the resin coating carrier, generally known styrene resin, acrylic resin, styrene acrylic copolymer resin, silicone resin, modified silicone resin, fluororesin, or a mixture thereof can be used.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the following examples, “part” means “part by mass”. In addition, the live-action test was conducted by the following method.
Each particle diameter, circularity, electrical conductivity and the like were measured as follows.

<Volume average diameter measurement (MV)>
The volume average diameter (MV) of particles with a volume average diameter (MV) of less than 1 micron is from Nikkiso Co., Ltd. Model Microtrac Nanotrac150 (hereinafter abbreviated as Nanotrack) and analysis software Microtrac Particle Analyzer Ver10.1.2-019EE The method described in the instruction manual using the ion-exchanged water having an electric conductivity of 0.5 μS / cm as the solvent, the solvent refractive index: 1.333, the measuring time: 600 seconds, and the number of times of measurement: once. Measured with Other setting conditions were particle refractive index: 1.59, transparency: transmission, shape: true sphere, density: 1.04.

<Volume median diameter of wax dispersion>
In order to determine the end point at the time of wax emulsification, Partica LA-950V2 (hereinafter abbreviated as LA950) manufactured by HORIBA, Ltd., which is a laser diffraction scattering type particle size distribution measuring apparatus capable of high-speed measurement, was used. The end point particle size at that time was set as the median diameter. The solvent used was ion exchange water having an electric conductivity of 0.5 μS / cm, and the measurement was performed by adjusting the sample amount in a concentration range of solvent refractive index: 1.333 and visible light transmittance of 70% to 90%.

<Measurement method and definition of median diameter (volume: Dv50 and number: Dn50)>
As a pre-measurement treatment of the toner finally obtained through the external addition process, it was performed as follows. In a cylindrical polyethylene (PE) beaker having an inner diameter of 47 mm and a height of 51 mm, 0.100 g of toner using a spatula, 20% by weight DBS aqueous solution using a dropper (Daiichi Kogyo Seiyaku Co., Ltd., Neogen S-20A) 0.15 g was added. At this time, toner and a 20% DBS aqueous solution were added only to the bottom of the beaker so that the toner would not scatter on the edge of the beaker. Next, the mixture was stirred for 3 minutes using a spatula until the toner and 20% DBS aqueous solution became a paste. At this time, the toner was prevented from being scattered on the edge of the beaker.
Subsequently, 30 g of dispersion medium Isoton II was added, and the mixture was stirred for 2 minutes using a spatula to obtain a uniform solution as a whole. Next, a fluororesin-coated rotor having a length of 31 mm and a diameter of 6 mm was placed in a beaker and dispersed using a stirrer at 400 rpm for 20 minutes. At this time, using a spatula at a rate of once every 3 minutes, macroscopic particles visually observed at the gas-liquid interface and the edge of the beaker were dropped into the beaker so as to form a uniform dispersion. Subsequently, this was filtered through a mesh having an opening of 63 μm, and the obtained filtrate was designated as “toner dispersion”.
For the measurement of the particle diameter during the manufacturing process of the toner base particles,
The filtrate filtered through a mesh of m was designated as “slurry liquid”.
The median diameter (Dv50 and Dn50) of the particles is Multisizer III manufactured by Beckman Coulter.
(Aperture diameter 100 μm) (hereinafter abbreviated as “Multisizer”), Isoton II made by the same company is used as a dispersion medium, and the above-mentioned “toner dispersion liquid” or “slurry liquid” is used with a dispersoid concentration of 0.03. Dilute to mass% and use a Multisizer III analysis software with a KD value of 118. Measured as 5. The measurement particle size range is from 2.00 to 64.00 μm,
This range is discretized into 256 divisions at equal intervals on a logarithmic scale, and the volume median diameter (Dv50) and the statistical value based on the number are calculated based on the statistical values based on the volume. The number median diameter (Dn50) was calculated as above.

<Measuring method and definition of average circularity>
The “average circularity” in the present invention is measured as follows and is defined as follows. That is, the toner base particles are dispersed in a dispersion medium (Isoton II, manufactured by Beckman Coulter, Inc.) in a range of 5720 to 7140 particles / μL, and a flow type particle image analyzer (manufactured by Sysmex Corporation, FPIA3000) is used. Measured under the following apparatus conditions, the value is defined as “average circularity”. In the present invention, the same measurement is performed three times, and an arithmetic average value of three “average circularity” is adopted as the “average circularity”.
・ Mode: HPF
-HPF analysis amount: 0.35 μL
-Number of HPF detected: 8,000-10,000 The following are measured by the above device and automatically calculated and displayed in the above device, but "roundness" is defined by the following formula The
[Circularity] = [Perimeter of a circle with the same area as the projected particle area] / [Perimeter of projected particle image]
Then, the number of HPF detected is 8,000 to 10,000, and the arithmetic average (arithmetic mean) of the circularity of each particle is displayed on the apparatus as “average circularity”.

  Gas chromatography Agilent 6890 (manufactured by Agilent Technologies) with a programmable temperature vaporization inlet was used to measure the carbon number of the wax and the structure was identified. As a separation column, a capillary column of 100% dimethylpolysiloxane (inner diameter 0) was used as the separation column. .25 mm / film thickness 0.10 μm / length 30 m), column temperature was 50 to 420 ° C. (temperature increase of 10 ° C./min), and carrier gas was measured using helium (flow rate 1 ml / min). Moreover, Agilent5973 (made by the company) was used for the mass spectrometry. Table 1 shows the values of the wax used and the carbon number composition of each wax.

<Manufacturing stability>
Regarding the stability of the emulsion during polymerization, the influence on the stirring due to adhesion to the vessel wall, precipitation, etc. was evaluated during the preparation of the polymer primary particle dispersion.
5: No adhesion or precipitation.
4: Slight adhesion is observed, but no effect.
3: Adhesion / precipitation is observed but stirring is possible.
2: Smooth stirring cannot be performed due to adhesion or precipitation on the vessel wall.
1: Stirring stops due to adhesion or precipitation on the vessel wall.

[Example 1]
<Adjustment of colorant dispersion>
Carbon black produced by a furnace method with a toluene extract having a UV absorbance of 0.02 and a true density of 1.8 g / cm ³ in a stirrer vessel equipped with a propeller blade (Mitsubishi Chemical Black, Mitsubishi Carbon Black) MA100S) 20 parts, anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen S-20D) 1 part, nonionic surfactant (manufactured by Kao Corporation, Emulgen 120) 4 parts, ion with conductivity 1 μS / cm 75 parts of exchange water was added and predispersed to obtain a pigment premix solution. The volume cumulative 50% diameter Dv50 of carbon black in the dispersion after premixing was about 90 μm. The premix solution was supplied as a raw material slurry to a wet bead mill and subjected to one-pass dispersion. Note that zirconia beads (true density 6.0 g / cm ³ ) having a diameter of 120 mmφ, a separator having a diameter of 60 mmφ, and a diameter of 50 μm were used as a dispersion medium. Since the effective internal volume of the stator is about 2 liters and the media filling volume is 1.4 liters, the media filling rate is 70%. When the rotational speed of the rotor is constant (the peripheral speed at the tip of the rotor is about 11 m / sec), the premix slurry is supplied from the supply port by a non-pulsating metering pump at a supply speed of about 40 liters / hr, and reaches a predetermined particle size. The product was acquired from the outlet. During operation, cooling water at about 10 ° C. was circulated from the jacket to obtain a colorant dispersion.

<Preparation of wax dispersion A1>
As wax 1, HiMic-1090 (manufactured by Nippon Seiwa: melting point 89 ° C.) 28.5 parts, decaglycerin decabehenate (acid value 3.2, hydroxyl value 27) 1.5 parts, 20% sodium dodecylbenzenesulfonate 2.8 parts of an aqueous solution (Daiichi Kogyo Seiyaku Co., Ltd., Neogen S20D, hereinafter abbreviated as 20% DBS aqueous solution) and 67.3 parts of demineralized water were added and heated to 100 ° C., and a homogenizer with a pressure circulation line (Gorin) Made by LAB 60-10TBS type) and subjected to primary circulation emulsification under a pressure of 10 MPa. The particle diameter is measured every few minutes with LA950, and when the median diameter is reduced to around 500 nm, the pressure condition is further increased to 25 MPa, followed by secondary circulation emulsification. A wax dispersion A1 was produced by dispersing until the median diameter was 230 nm or less. The volume median diameter of the wax dispersion was 227 nm.

<Preparation of polymer primary particle dispersion B1>
35.7 parts (182.0 kg) of the above wax dispersion A1 and 259 parts of demineralized water were added to a reactor equipped with a stirring device (three blades), a heating / cooling device, a concentrating device, and each raw material / auxiliary charging device. While charging and stirring, the temperature was raised to 90 ° C. under a nitrogen stream.
Thereafter, the mixture of the following “polymerizable monomers and the like” and “emulsifier aqueous solution” was added to the solution over 5 hours while continuing to stir the liquid. The time at which this mixture was started to be dropped was designated as “polymerization start”, and the following “initiator aqueous solution” was added over 4.5 hours from 30 minutes after the start of polymerization. Further, after 5 hours from the start of polymerization, the following “additional start” The agent aqueous solution ”was added over 2 hours, and the internal temperature was maintained at 90 ° C. for 1 hour while continuing stirring.
[Polymerizable monomers, etc.]
Styrene 74.5 parts Butyl acrylate 25.5 parts Acrylic acid 1.5 parts Hexanediol diacrylate 0.7 parts Trichlorobromomethane 1.0 part
[Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part
67.1 parts of demineralized water
[Initiator aqueous solution]
8% by mass aqueous hydrogen peroxide solution 15.5 parts 8% by mass L (+)-ascorbic acid aqueous solution 15.5 parts
[Additional initiator aqueous solution]
8 mass% L (+)-ascorbic acid aqueous solution 14.2 parts It cooled after completion | finish of polymerization reaction, and milky-white polymer primary particle dispersion liquid B1 was obtained. The volume average diameter (Mv) measured using Nanotrac was 275 nm, and the solid content concentration was 22.6% by mass.

<Manufacture of toner mother particle C1>
Using the following components, toner base particles C1 were produced by carrying out the following aggregation process (core material aggregation process / shell coating process) / circularization process.
Polymer primary particle dispersion B1 80 parts as solid content (Dispersion B1: 280.0 kg / solid content: 63.3 kg for core)
Polymer primary particle dispersion B1 20 parts as solid content (dispersion B1: 70.0 kg / solid content: 15.8 kg for shell)
Colorant fine particle dispersion 6.0 parts 20% DBS aqueous solution as a colorant solid content In the rounding step, 6 parts as a solid content

○ Core material aggregation process
Polymer primary particle dispersion B1 is charged into a mixer (volume: 1000 L, inner diameter: 850 mm) equipped with a stirrer (double helical blade), heating / cooling device and raw material / auxiliary charging device, and uniform at an internal temperature of 10 ° C. for 10 minutes. Mixed. Then at an internal temperature of 10 ° C., allowed to stir at 101Rpm, a 5 wt% aqueous solution of potassium sulfate _from continuously added over 1 minute 0.12 parts as K 2 SO _4, the colorant particle dispersion liquid 5 The mixture was continuously added over a minute and mixed uniformly at an internal temperature of 10 ° C.
Thereafter, 0.3 part by weight of an aqueous solution of 0.5% by mass of aluminum sulfate was continuously added over 30 minutes, and the internal temperature was raised to 48.0 ° C. over 70 minutes while maintaining the rotation speed at 101 rpm ( 0.5 ° C./min). Subsequently, after raising the temperature by 1 ° C. every 30 minutes (0.03 ° C./min), the temperature was maintained at 54.0 ° C., and the volume median diameter was measured using a multisizer to grow to 5.12 μm.

○ Shell coating process
Thereafter, with the internal temperature of 54.0 ° C. and the rotation speed of 101 rpm, the polymer primary particle dispersion B1 was continuously added over 15 minutes and held as it was for 60 minutes. At this time, Dv50 of the particles was 5.44 μm.

○ Circularization process
Subsequently, the mixture was heated to 90 ° C. while adding a mixed aqueous solution of 20% DBS aqueous solution (6 parts as a solid content) and 0.04 part of water over 30 minutes with the same rotation speed, and thereafter every 30 minutes. The temperature was raised to 1 ° C., raised to 95 ° C., and heating and stirring were continued under these conditions until the average circularity reached 0.968 over 2.5 hours. Thereafter, the mixture was cooled to 20 ° C. over 50 minutes to obtain a slurry of toner base particles C1. At this time, the volume median diameter of the particles was 5.55 μm, the number median diameter was 5.17 μm, the distribution Dv50 / Dn50 was 1.07, and the average circularity was 0.968.

○ Washing and drying process Using a wet electromagnetic sieve shaker (AS200 / Lecche Co., Ltd.) equipped with a sieve with a mesh size of 24μm, the resulting slurry is filtered for the purpose of removing coarse particles and equipped with a stirrer Once stored in the tank. Thereafter, this slurry was subjected to a horizontal centrifuge (HZ40Si type / Mitsubishi Chemical Corporation) equipped with a filter cloth (polyester TR815C, Nakao filter industry / thickness 0.3 mm / air permeability 48 (cc / cm ² / min)). Then, centrifugal dehydration washing was performed under the condition of acceleration 800G. When ion-exchanged water having an electric conductivity of 1 μS / cm was added at a rate not to overflow from the rim at about 50 times the amount of slurry solids, the electric conductivity of the filtrate was 2 μS / cm. Finally, water was thoroughly shaken off, and the cake was recovered with a scraping device.
The obtained cake was spread on a stainless steel bat so as to have a height of 20 mm, and dried in a blow dryer set at 40 ° C. for 48 hours to obtain toner mother particles C1.

<Manufacture of developing toner D1: external addition process>
Toner toner particle C1 obtained by mixing 50 g of H05TD silica manufactured by Clariant Co., Ltd. and 15 g of H30TD silica manufactured by Co., Ltd. as an external additive, is mixed with 2500 g of the obtained toner base particle C1 with a Henschel mixer (Mitsui Mine Co., Ltd.), and sieved with 150 mesh. Got.

[Example 2]
<Preparation of wax dispersion A2>
Composition: wax 1 26.7 parts, pentaerythritol tetrastearate (acid value 3.0, hydroxyl value 1.0) 3.0 parts, decaglycerin decabehenate (hydroxyl value 27) 0.3 parts, 20% A wax dispersion A2 was prepared in the same manner as A1, except that 2.8 parts of DBS aqueous solution and 67.3 parts of demineralized water were used. The volume median diameter of the wax dispersion was 215 nm.

<Preparation of polymer primary particle dispersion B2>
Polymer primary particle dispersion B2 was obtained in the same manner as B1, except that 35.3 parts of wax dispersion A2 was used instead of wax dispersion A1, and the amount of water was 260 parts. The volume average particle size (MV) was 248 nm, and the solid content concentration was 22.7% by mass.

<Production of toner base particles C2>
Developing mother particles C2 were obtained in the same manner as C1, except that B2 was used instead of the polymer primary particle dispersion B1 and the temperature was raised to 49 ° C. at 0.5 ° C./min. The volume median diameter (Dv50) was 5.68 μm, Dv50 / Dn50 was 1.08, and the average circularity measured by a flow particle analyzer was 0.968.

<Manufacture of developing toner D2>
A developing toner D2 was obtained in the same manner as D1, except that C2 was used instead of the developing mother particle C1.

[Example 3]
<Preparation of wax dispersion A3>
Composition: wax 2 (HNP-0190 / manufactured by Nippon Seiwa: melting point 89 ° C.) 26.7 parts, pentaerythritol tetrastearate (acid value 3.0, hydroxyl value 1.0) 3.0 parts, decaglycerin decabe A wax dispersion A3 was produced in the same manner as A1, except that 0.3 part of henate (hydroxyl value 27), 2.8 parts of 20% DBS aqueous solution, and 67.3 parts of demineralized water were used. The volume median diameter of the wax dispersion was 228 nm.

<Preparation of polymer primary particle dispersion B3>
In the same manner as B2, except that the wax dispersion A3 was used instead of the wax dispersion A2, and the monomer composition ratio was changed as follows by changing the butyl acrylate to 2-ethylhexyl acrylate. A particle dispersion B3 was obtained.
[Polymerizable monomers, etc.]
Styrene 79.8 parts Butyl acrylate 20.3 parts Acrylic acid 1.5 parts Hexanediol diacrylate 0.7 parts Trichlorobromomethane 1.0 part

  The volume average particle size (MV) was 255 nm, and the solid content concentration was 22.7% by mass.

<Manufacture of toner mother particles C3>
Developing mother particles C3 were obtained in the same manner as C2, except that B3 was used instead of the polymer primary particle dispersion B2 and the temperature was raised to 50 ° C. at 0.5 ° C./min. The volume median diameter (Dv50) was 5.62 μm, Dv50 / Dn50 was 1.07, and the average circularity measured by a flow particle analyzer was 0.968.

<Manufacture of developing toner D3>
A developing toner D3 was obtained in the same manner as in D1, except that C3 was used instead of the developing mother particle C1.

[Comparative Example 1]
<Preparation of wax dispersion A4>
A wax dispersion A4 was prepared in the same manner as A1, except that the composition was wax 5 (HNP-9 / manufactured by Nippon Seiwa). The volume median diameter of the wax dispersion was 230 nm.

<Preparation of polymer primary particle dispersion B4>
A polymer primary particle dispersion B4 was obtained in the same manner as in B1, except that the wax dispersion A4 was used instead of the wax dispersion A1. The volume average particle size (MV) was 260 nm, and the solid content concentration was 22.6% by mass.

<Manufacture of toner mother particles C4>
Developing mother particles C4 were obtained in the same manner as C1, except that B4 was used instead of the polymer primary particle dispersion B1 and the temperature was raised to 47 ° C. at 0.5 ° C./min. The volume median diameter (Dv50) was 5.77 μm, Dv50 / Dn50 was 1.09, and the average circularity measured by a flow particle analyzer was 0.967.

<Manufacture of development toner D4>
A developing toner D4 was obtained in the same manner as in D1, except that C4 was used instead of the developing mother particle C1.

[Comparative Example 2]
<Preparation of wax dispersion A5>
A wax dispersion A5 was produced in the same manner as A4 except that the composition was wax 6 (HNP-1 / manufactured by Nippon Seiwa) and the pressure was 20 MPa. The volume median diameter of the wax dispersion was 228 nm.

<Preparation of polymer primary particle dispersion B5>
Polymer primary particle dispersion B5 was obtained in the same manner as B4 except that 35.7 parts of wax dispersion A5 were used instead of wax dispersion A4. The volume average particle size (MV) was 262 nm, and the solid content concentration was 22.6% by mass.

<Manufacture of toner mother particles C5>
Developing mother particles C5 were obtained in the same manner as C4 except that B5 was used instead of the polymer primary particle dispersion B4. The volume median particle size (Dv50) was 5.75 μm, the distribution was 1.10, and the average circularity measured by a flow particle analyzer was 0.967.

<Manufacture of developing toner D5>
A developing toner D5 was obtained in the same manner as D4 except that C5 was used instead of the developing mother particle C4.

[Comparative Example 3]
<Preparation of wax dispersion A6>
A wax dispersion A6 was produced in the same manner as A2, except that the composition was wax 3 (HiMic-1080 / manufactured by Nippon Seiwa). The volume median diameter of the wax dispersion was 220 nm.

<Preparation of polymer primary particle dispersion B6>
A polymer primary particle dispersion B6 was obtained in the same manner as B2, except that the wax dispersion A6 was used instead of the wax dispersion A2. The volume average particle size (MV) was 247 nm, and the solid content concentration was 22.8% by mass.

<Production of toner mother particles C6>
Developing mother particles C6 were obtained in the same manner as C2, except that B6 was used instead of the polymer primary particle dispersion B2 and the temperature was raised to 46 ° C at 0.5 ° C / min. The volume median diameter (Dv50) was 5.65 μm, Dv50 / Dn50 was 1.08, and the average circularity measured by a flow particle analyzer was 0.968.

<Manufacture of developing toner D6>
A developing toner D6 was obtained in the same manner as D2, except that C6 was used instead of the developing mother particle C2.

[Comparative Example 4]
<Preparation of wax dispersion A7>
A wax dispersion A7 was produced in the same manner as A2, except that the composition was wax 4 (HiMic-1070 / manufactured by Nippon Seiwa). The volume median diameter of the wax dispersion was 208 nm.

<Preparation of polymer primary particle dispersion B7>
A polymer primary particle dispersion B7 was obtained in the same manner as in B2, except that the wax dispersion A7 was used instead of the wax dispersion A2. The volume average particle size (MV) was 277 nm, and the solid content concentration was 22.4% by mass. When the inside of the tank was confirmed after the polymerization, many deposits and precipitates were observed on the stirring blade.

<Manufacture of toner mother particles C7>
Developing mother particles C7 were obtained in the same manner as C6 except that B7 was used instead of the polymer primary particle dispersion B6. The volume median diameter (Dv50) was 5.88 μm, Dv50 / Dn50 was 1.13, and the average circularity measured by a flow particle analyzer was 0.967.

<Manufacture of developing toner D7>
A developing toner D7 was obtained in the same manner as D2, except that C7 was used instead of the developing mother particle C2.

[Example 4]
<Preparation of wax dispersion A8>
Add 1/3 amount of wax 2 to 2/3 amount of wax 3 and melt in advance at 100 ° C. or higher and stir and mix. 26.7 parts of this as wax 7, 3.0 parts of pentaerythritol tetrastearate (acid value 3.0, hydroxyl value 1.0), 0.3 parts of decaglycerin decabehenate (hydroxyl value 27), 20 2.8 parts of a% DBS aqueous solution and 67.3 parts of demineralized water were added and heated to 105 ° C., and primary circulation emulsification was performed under a pressure condition of 10 MPa using a homogenizer with a pressure circulation line. The particle diameter is measured every few minutes with LA950, and when the median diameter is reduced to around 500 nm, the pressure condition is further increased to 28 MPa, followed by secondary circulation emulsification. A wax dispersion A8 was produced by dispersing until the median diameter became 230 nm or less. The volume median diameter of the wax dispersion was 217 nm.

<Preparation of polymer primary particle dispersion B8>
A polymer primary particle dispersion B8 was obtained in the same manner as in B2, except that the wax dispersion A8 was used instead of the wax dispersion A2. The volume average particle size (MV) was 252 nm, and the solid content concentration was 22.7% by mass.

<Manufacture of toner mother particles C8>
Developing mother particles C8 were obtained in the same manner as C2, except that B8 was used instead of the polymer primary particle dispersion B2. The volume median particle size (Dv50) was 5.59 μm, Dv50 / Dn50 was 1.07, and the average circularity measured by a flow particle analyzer was 0.968.

<Manufacture of developing toner D8>
A developing toner D8 was obtained in the same manner as D2, except that C8 was used instead of the developing mother particle C2.

[Comparative Example 5]
<Preparation of wax dispersion A9>
Add 30.0 parts of wax 1, 4.1 parts of 20% DBS aqueous solution and 66.9 parts of demineralized water to add 10 parts.
The mixture was heated to 5 ° C., and primary circulation emulsification was performed under a pressure condition of 10 MPa using a homogenizer with a pressure circulation line. The particle diameter is measured every few minutes with LA950, and when the median diameter is reduced to around 500 nm, the pressure condition is further increased to 30 MPa, followed by secondary circulation emulsification. Since the distribution was broad and the volume median diameter did not easily become 230 nm or less, the volume median diameter of the wax dispersion was set to 247 nm. This wax dispersion was designated as A9.

<Preparation of polymer primary particle dispersion B9>
The primary polymer particle dispersion B9 was prepared in the same manner as B2 except that the wax dispersion A9 was used instead of the wax dispersion A2, but a large amount of adhesion to the vessel wall occurred during the polymerization and the stirring was stopped. However, the polymerization could not be continued.

[Comparative Example 6]
<Preparation of wax dispersion A10>
Add ¼ amount of wax 5 to ¼ amount of wax 1 and melt in advance at 100 ° C. or higher and stir and mix. A wax dispersion A10 was produced in the same manner as A8 except that this was changed to wax 8. The volume median diameter of the wax dispersion was 214 nm.

<Preparation of polymer primary particle dispersion B10>
A polymer primary particle dispersion B10 was obtained in the same manner as B2, except that the wax dispersion A10 was used instead of the wax dispersion A2. The volume average particle size (MV) was 253 nm, and the solid content concentration was 22.7% by mass.

<Manufacture of toner mother particles C9>
Developing mother particles C9 were obtained in the same manner as C8, except that B10 was used instead of the polymer primary particle dispersion B8. The volume median diameter (Dv50) was 5.65 μm, Dv50 / Dn50 was 1.08, and the average circularity measured by a flow particle analyzer was 0.969.

<Manufacture of developing toner D9>
A developing toner D9 was obtained in the same manner as D2, except that C9 was used instead of the developing mother particle C2.

<Fixing test>
When recording paper carrying an unfixed toner image is prepared, the surface temperature of the heating roller is changed from 100 ° C. to 215 ° C. in increments of 5 ° C., conveyed to the fixing nip, and discharged at a speed of 120 mm / sec. The fixing state of was observed. The temperature range where the toner on the recording paper after fixing does not cause toner offset or paper wrapping at the time of fixing and the toner on the recording paper after fixing is sufficiently adhered to the recording paper is defined as the fixing temperature range. The heating roller of the fixing machine has a release layer made of PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), and was evaluated without application of silicone oil.
A (Good): Offset occurs at a fixing temperature of + 50 ° C. or higher.
○ (Practical use possible): Offset occurs at a fixing temperature of + 40 ° C. or higher and lower than 50 ° C.
Δ (insufficient): Offset occurs at a fixing temperature of + 30 ° C. or higher and lower than 40 ° C.
X (Unusable): Offset at a fixing temperature of less than + 30 ° C.

<Toner cohesion>
The toner cohesiveness was confirmed by a vibration sieve measurement method using a three-stage mesh. The aggregation degree measurement method is as follows.
Using a powder tester manufactured by Hosokawa Micron Co., Ltd., three types of sieves are stacked and fixed, and a sample is placed on the shaking table. The measurement conditions are as follows.
Mesh opening (top) 250μm (60 mesh)
Mesh opening (medium) 150μm (100 mesh)
Mesh opening (bottom) 75μm (200 mesh)
Swing scale scale 1.0mm
Sampling amount 2.0g
Vibration time 90 seconds

After the measurement, the degree of aggregation is obtained from the following calculation.
(Weight of powder remaining in upper mesh / amount of sample collected) × 100
(Weight of powder remaining in middle mesh / sample collection amount) × 100 × 0.6
(Weight of powder remaining in lower mesh / sample collection amount) × 100 × 0.2
The total of the above three calculated values is defined as the degree of aggregation (%). The judgment is as follows.
○ (Practical use possible): Less than 10% Δ (Insufficient): 10% or more and less than 20% × (Unusable): 20% or more

<Blocking resistance>
10 g of developing toner is put into a cylindrical container having an inner diameter of 3 cm and a height of 6 cm, a load of 20 g is put on it, left in an environment of 50 ° C. and 40% RH for 24 hours, and then the toner is taken out of the container and loaded from above. The degree of toner consolidation was confirmed.
◎ (Good): Even if no load is applied, it collapses and does not solidify.
○ (Practical use possible): Solidified but collapsed with a load of less than 50 g.
Δ (insufficient): solidified and collapsed with a load of 50 g or more and less than 200 g.
X (Unusable): It is consolidated and does not collapse unless a load of 200 g or more is applied.

<Dust generation amount (Emission rate)>
Place all four development toners in the cartridge of the color page printer ML9600PS (Oki Data Co., Ltd.), collect the dust according to the Blue Angel Mark certified measurement method (RAL_UZ122_2006), and measure the mass of the substance collected on the filter The dust release rate was calculated from the above. Specifically, after the blanking measurement was performed by baking the emission test chamber (VOC-010 / volume 1000 L / manufactured by Espec) in advance, the printer and the dust measurement filter were installed, and for 60 minutes. Wait so that the temperature and humidity in the tank are within the specified range (23 ± 2 ℃ / 50 ± 5%). At the same time when the printer was operated by remote control, suction from the filter was started, and a specified number of sheets were printed, and suction collection was performed until 2 hours later. The print pattern used was VE110-7, Version 2006-06-01 (RAL_UZ122 / RALC00.PDF).

The dust emission rate was obtained from the following equation.
(1) Dust mass after temperature and humidity correction
_{m St = (m MFbrutto -m MFtara} ) + (m RF1 -m RF2)
m _MFtara : Weight of measurement filter with stable mass before dust sampling (mg)
m _MFbruto : Weight of the measurement filter with stable mass after dust sampling (mg)
m _RF1 : Weight of reference filter before test (mg)
m _RF2 : Weight of reference filter after test (mg)
(2) Dust dissipation rate EF _uSt = (m _St × n × V × t _o ) / (V _S × t _p )
n: Ventilation frequency (h ^-1 )
t _o : Total sampling time (min)
t _p : Printing time (min)
V: chamber volume (m ³ )
V _S : volume of air sucked through the filter (m ³ )

  Table 2 shows the toner evaluation results. As is clear from this, all of Examples 1 to 3 were good in production stability, fixability, and blocking resistance. Further, the amount of dust generated was also sufficiently lower than the blue angel regulation value: 4 mg / h or less. On the other hand, Comparative Examples 1 and 2 using waxes with insufficient composition ratios of C ≧ 40 and C ≧ 30 had a very large dust amount and low offset resistance. Further, in Comparative Examples 3 and 4 where the non-normal composition ratio of carbon number C ≧ 40 is larger than the range of the present invention, the toner fluidity was remarkably deteriorated. In Comparative Example 5, which was the same wax as in Example 1 and did not contain a polyglycerin fatty acid ester, it could not be used as toner base particles.

  In Example 4 using the wax 7 which falls within the scope of the present invention by making the wax 3 having a problem alone the main component and adding the wax 2, the toner cohesiveness is also improved, and in all items. Practically no problem. On the other hand, in Comparative Example 6 using wax 8 in which 20% of paraffinic wax 5 was mixed with wax 1 that was sufficiently good alone, the condition with only carbon number C ≧ 40 was slightly less than the scope of the present invention. As a result, the offset resistance and the amount of dust generated deteriorated.

Claims (7)

In the toner containing at least a polyglycerin fatty acid ester, a binder resin, and a hydrocarbon wax, the wax has a component having a carbon number of 40 or more of 80% or more of the total amount of the hydrocarbon wax and a hydrocarbon having a carbon number of 40 or more. Among them, the toner for developing an electrostatic image, wherein the non-normal component is 18% or more and 40% or less of the total amount of the hydrocarbon wax. The toner for developing an electrostatic charge image according to claim 1, wherein the polyglycerin fatty acid ester is contained in an amount of 0.01 to 10 parts by mass in 100 parts by mass of the toner. 3. The electrostatic image developing toner according to claim 1, wherein the acid value of the polyglycerol fatty acid ester is 1 mg-KOH / g or more. The volume median diameter (Dv50) is 4 μm or more and 7 μm or less, and the particle size distribution Dv50 / Dn50 represented by the ratio of the volume median diameter to the number median diameter (Dn50) is 1.1 or less. 4. The electrostatic image developing toner according to claim 1, wherein The electrostatic image developing toner according to claim 1, wherein the toner is produced by a polymerization method. 6. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein polyglycerin fatty acid ester is added in the step of producing a wax dispersion by dispersing hydrocarbon wax in a dispersion medium. 7. The method for producing a toner for developing an electrostatic charge image according to claim 6, wherein the volume median diameter of the wax dispersion in the wax dispersion is 0.01 μm or more and 1 μm or less.