JP2017181573A - Toner for electrostatic charge image development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development that ensures satisfactory rising of chargeability even when used for a non-magnetic one-component developing system, has sufficient fluidity, and stabilizes image performance under printing stress continuing for a long period.SOLUTION: There is provided a toner for electrostatic charge development containing at least two external additives on the surface of a toner base particle, where one of the two external additives is colloidal silica fine particles subjected to hydrophobic treatment by using a silane coupling agent and organosilazane, and the other is melamine resin particles; and the volume average particle diameter of the colloidal silica fine particles is 20 nm or less.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing toner used in electrophotography, electrostatic photography, and the like.

  In general, an electrophotographic method forms an electrostatic latent image on a photoconductive photoreceptor by various methods, and then visualizes the latent image using an electrostatic charge image developing toner (hereinafter abbreviated as “toner”). After that, there is a step of transferring the toner visible image onto a transfer material such as paper and fixing the toner image by heating or pressurizing. Various methods are known as these steps, and those suitable for each image forming process are employed.

  One of the typical toner manufacturing methods is a pulverization method that melts and mixes various materials such as binder resins, colorants, and charge control agents, and then pulverizes and classifies them into fine powders. In general, it is widely used regardless of color, monochrome, and various development methods. In addition, research and development of polymerized toners are actively conducted to meet the demand for higher speed and higher image quality in recent electrophotography. Since the particle size of the polymerized toner is easier to control than the pulverized toner, it is possible to obtain toner mother particles having a small particle size suitable for high image quality. Further, since the toner can be encapsulated by controlling the particle structure, there is an advantage that a toner excellent in heat resistance and low-temperature fixability can be obtained. In addition, since it has a relatively rounded shape and stress applied during continuous shooting is alleviated, it is relatively easy to cope with high-speed processing and high printing durability particularly required for large-sized copier printers.

  In addition to the characteristics of the polymerized toner as described above, various studies have been made to obtain a stable high image quality by a process that is more stressful. For example, a technique is known in which inorganic fine particles having a specific charge amount and particle diameter are externally added to obtain a stable charge amount and high image quality. Silica fine particles are generally used as the inorganic fine particles used for them. Combustion method silica (fumed silica) obtained by burning a silane compound, decombustion method silica obtained by explosively burning metal silicon powder, and neutralization reaction between sodium silicate and mineral acid. It is roughly divided into wet silica, colloidal silica obtained by polymerizing acidic silicic acid obtained by sodium removal from sodium silicate with an ion exchange resin, and sol-gel silica obtained by hydrolysis of hydrocarbyloxysilane.

  As a hydrophobizing treatment method, a hydrophobizing treatment is performed by bringing silica fine particles into contact with a hydrophobizing agent such as a surfactant, silicone oil, or a gas of a silylating agent such as alkyl halogen silane, alkyl alkoxy silane, or alkyl disilazane. And a hydrophobizing treatment by contacting with a silylating agent in a mixed solvent of water and hydrophilic organic.

  Such hydrophobized surface-treated silica fine particles are suitably used as an external additive for toner for electrophotography, but the problem is the environmental stability of the toner charge amount, and the high temperature and high humidity Alternatively, an external additive with little change in charge amount even under low temperature and low humidity is desired.

  On the other hand, when the charge of the toner is low or the charge rise is poor, the toner with poor charge adheres to the background portion that should be white, causing an image defect called fogging. In addition, the chargeability is sensitively affected by temperature and humidity. In particular, in a high-temperature and high-humidity environment, the toner is reduced in charge, resulting in further fogging. In order to prevent this, various studies for improving the charging property have been made. As one of them, a technique for attaching positively chargeable particles to the surface of a negatively chargeable toner is known. This is used as a so-called microcarrier that improves the negative chargeability of the toner by the presence of a small amount of positively charged particles in the system when the toner is triboelectrically charged. Materials have been studied.

  For example, in Patent Document 1, by performing hydrolysis in a mixed liquid of a hydrophilic organic solvent and water in which a silane compound or a partial hydrolysis product thereof is dispersed in a volume-based median of 0.01 to 5 μm. Hydrophobic spherical silica fine particles are produced by treating the surface of the silica fine particles with a silane compound or a partially hydrolyzed product thereof in the mixed dispersion to produce hydrophobized spherical silica fine particles. It has been reported that a toner charge amount excellent in environmental stability can be obtained by using as an agent.

  Moreover, in patent document 2, both the affinity for resin and the effect of suppressing aggregation between particles are achieved by setting the silane coupling agent and organosilazane to a specific range for silica particles having a volume average particle diameter of 5 nm to 100 nm. In other words, there is disclosed a technique for satisfactorily dispersing small-diameter silica particles in a resin composition while maintaining high fluidity.

  Patent Document 3 reports that the use of melamine-based resin particles exhibiting a strong positive charging property as an external additive for the toner improves adhesion of the toner by adhering it to the surface of the negatively charging toner. Yes.

JP, 2014-114175, A JP 2012-214554 A Japanese Patent Laying-Open No. 2015-14806

  However, colloidal silica as described in Patent Document 1 is often used with a relatively large particle diameter of 50 nm or more compared to dry silica typified by fumed silica, which is higher than dry silica. Although charging stability under high humidity is improved, the effect of imparting fluidity and charging property to the added amount is low, and it cannot provide sufficient toner performance by itself. Therefore, in general, by adding a small particle size dry silica particle subjected to a hydrophobization treatment with an average particle size of 20 nm or less, fluidity and chargeability can be improved, but dry silica having a small particle size is Aggregation is strong, and if aggregation occurs on the surface of the toner base particles, sufficient fluidity and chargeability cannot be imparted.

  On the other hand, the melamine resin particles for improving the chargeability as described in Patent Document 3 have the advantage of improving the chargeability of the toner and at the same time remarkably lowering the toner fluidity. There is a demerit that it is easily contaminated. In recent years, there has been a further increase in the demands for high-definition image quality, high-speed machines, and long developer life in electrophotography, all of which are in the direction of promoting member contamination. In addition, the non-magnetic one-component development method is more advantageous than the two-component development method due to its simple structure, which is advantageous for downsizing and maintenance of the apparatus, while the stress on the toner from the toner layer regulating member is severe, and the flow Toner with low properties causes toner aggregation within the developing tank, leading to poor image quality. Therefore, when toner using melamine resin particles is used, image defects such as afterimages due to contamination of the surface of the photoreceptor occur in addition to the above-mentioned aggregation due to the decrease in fluidity of the toner. More difficult to use. In the non-magnetic one-component development method, the toner charge rising is particularly important. For this reason, when a large amount of melamine resin particles are added, toner aggregation and member contamination are further deteriorated. .

  The present invention has been made in view of the above problems. That is, the object of the present invention is that, even when used in a non-magnetic one-component development method, the rising of the charge is good, the fluidity is sufficient, and the image performance is stable under long-term continuous printing stress. The toner provides an electrostatic charge image developing toner.

  As a result of repeated studies to solve the above-mentioned problems, the present inventors have attached or adhered melamine-based resin particles to the surface of the toner base particles in the external addition step together with colloidal silica whose surface has been hydrophobized by a specific method. It has been found that by fixing, a toner having good charge rising, sufficient fluidity, and stable performance under long-term continuous printing stress can be obtained. That is, the gist of the present invention is as follows.

<1> An electrostatic charge image developing toner having at least two or more types of external additives on the surface of toner base particles, wherein one of the two or more types of external additives includes a silane coupling agent and an organosilazane. The colloidal silica fine particles hydrophobized by using the other, the other one is melamine resin particles, and the volume average particle size of the colloidal silica fine particles is 20 nm or less, electrostatic image development Toner.

<2> The toner for developing an electrostatic charge image according to <1>, wherein the amount of the colloidal silica fine particles added to 100 parts of the toner base particles is 0.6 part or more and 1.0 part or less.

<3> The electrostatic charge image according to <1> or <2>, wherein the number of added parts of the melamine resin fine particles to 100 parts of the toner base particles is 0.005 part or more and 0.100 part or less. Development toner.

<4> Any one of <1> to <3>, wherein the number of added parts of the melamine-based resin fine particles with respect to 100 parts of the toner base particles is 0.010 part or more and 0.035 part or less. The toner for developing an electrostatic image according to the description.

<5> The electrostatic charge image developing according to any one of <1> to <4>, wherein SF2 of the toner base particles represented by the following formula (1) is 120 or less: Positively charged toner.

Formula (1): SF2 = (T ² / S) × (1 / 4π) × 100

(In the above equation (1), S represents the projected area of the particle, and T represents the perimeter of the projected particle image.)

<6> The toner for developing an electrostatic charge image according to any one of <1> to <5>, wherein the toner base particles contain at least a binder resin and a colorant.

  According to the present invention, there is provided an electrostatic image developing toner that has high fluidity, does not cause image defects, has excellent chargeability, has good fog, and is suitable for use in a high-speed and long-life machine. Can do.

  Hereinafter, the present invention will be described in detail, but the present invention is not limited to the following embodiments, and can be arbitrarily modified without departing from the gist of the present invention. Hereinafter, the “positively charged toner for developing an electrostatic image” may be simply abbreviated as “toner”. The toner before the external additive is fixed or adhered is referred to as “toner mother particles”.

<Configuration of Toner of the Present Invention>
The toner of the present invention is an electrostatic charge image developing toner having at least two or more kinds of external additives on the surface of toner base particles. One of the two or more external additives is a colloidal silica fine particle hydrophobized using a silane coupling agent and an organosilazane, the other one is a melamine resin particle, and the colloidal silica The volume average particle diameter of the fine particles is 20 nm or less.

<Colloidal silica fine particles whose surface is hydrophobized with a silane coupling agent and organosilazane>
In order to suppress fogging due to toner charging failure and to improve image quality defects such as blurring and unevenness due to toner aggregation, the volume average primary particle size whose surface is hydrophobized with a silane coupling agent and organosilazane is 20 nm. It is essential to use the following colloidal silica fine particles. Compared to dry silica particles, colloidal silica particles not only provide a spacer effect when externally added to the toner, but also reduce the stress on the toner, as well as improving the charging stability in high-temperature, high-humidity and low-temperature, low-humidity environments. I can do it. On the other hand, colloidal silica fine particles are produced in a liquid phase medium, but when dried in the solvent removal step, the colloidal silica fine particles induce aggregation between the colloidal silica fine particles. Will be further encouraged. Therefore, when the colloidal silica fine particles are externally added to the toner, if the aggregates of the silica fine particles cannot be sufficiently dispersed, sufficient effects on fluidity and chargeability cannot be exhibited. Therefore, by treating the surface with a silane coupling agent and organosilazane, even if the silica particles are small, aggregation of the particles is suppressed, and when externally added to the toner, the fluidity and chargeability are reduced. It is possible to exert a high imparting effect.

  Specific examples of silane coupling agents include phenyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane. 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-phenyl-3 -Aminopropyltrimethoxysilane.

  Specific examples of the organosilazane include tetramethyldisilazane, hexamethyldisilazane, and pentamethyldisilazane.

Among them, the functional group represented by the formula (2): -OSiX ¹ X ² X ³ and the functional group represented by the formula (3): -OSiY ¹ Y ² Y ³ are bonded to the silica particle surface. It is preferable that In the above formulas (2) and (3), X ¹ is a phenyl group, vinyl group, epoxy group, methacryl group, amino group, ureido group, mercapto group, isocyanate group, or acrylic group, and X ² , X ³ independently represents —OSiR ³ or —OSiY ⁴ Y ⁵ Y ⁶ , Y ⁴ represents R, Y ⁵ and Y ⁶ each independently represent R or —OSiR ₃ , and R represents a carbon number of 1 Represents an alkyl group of ˜3. Aggregation of silica particles can be suppressed by the repulsive force between the alkyl groups having 1 to 3 carbon atoms.

The colloidal silica fine particles are not particularly limited as long as the effects of the present invention are not significantly impaired. However, the colloidal silica fine particles preferably include any of the following (i) to (iii), and more preferably include a plurality of (i) to (iii). preferable.
(I) The abundance ratio between the functional group represented by the formula (2) and the functional group represented by the formula (3) is 1:12 to 1:60.
(Ii) X ¹ is 0.5 to 2.5 per unit surface area (nm ² ) of the colloidal silica fine particles.
(Iii) R is 1 to 10 per unit surface area (nm ² ) of the colloidal silica fine particles.

  The surface treatment method of colloidal silica fine particles has a surface treatment step of surface-treating silica particles with a silane coupling agent and an organosilazane in a liquid medium containing water. The silane coupling agent includes three alkoxy groups, phenyl Group, vinyl group, epoxy group, methacryl group, amino group, ureido group, mercapto group, isocyanate group, or acrylic group, and the molar ratio of the silane coupling agent to the organosilazane is the silane coupling agent. : The organosilazane = 1: 2 to 1:10. The functional group derived from the silane coupling agent represented by the above formula (2) and the functional group derived from the organosilazane represented by the above formula (3) can be bonded to the surface of the silica particles. And if the molar ratio of a silane coupling agent and organosilazane is in the range of 1: 2 to 1:10, the functional group represented by the above formula (2) and the functional group represented by the above formula (3). Can be present in a well-balanced manner on the surface of the colloidal silica fine particles. This makes it possible to obtain colloidal silica fine particles having both toner chargeability and fluidity when externally added to the toner.

  Since colloidal silica fine particles improve fluidity, it is preferable that the new sphericity is high. The new sphericity is preferably 0.8 or more, and more preferably 0.9 or more. The measurement of sphericity is a value calculated from the area and perimeter of the observed particle by taking a photograph with SEM, and randomly using an image processing device (Sysmex Corporation: FPIA-3000). An average value measured for 100 extracted particles is adopted. The colloidal silica fine particles can be produced, for example, by the method described in JP2012-214554.

  The volume average primary particle size of the colloidal silica fine particles is 20 nm or less, the lower limit is usually 5 nm or more, and preferably 10 nm or more from the viewpoint of suppressing the burying of the external additive in the toner base particles. The content of the colloidal silica fine particles is usually 0.2 parts by mass or more with respect to 100 parts by mass of the toner base particles, and preferably 0.6 parts by mass or more from the viewpoint of fogging due to insufficient chargeability. On the other hand, the amount is usually 1.4 parts by mass or less, and is preferably 1.0 part by mass or less from the viewpoint of silica liberated from the toner base particles contaminating members in the developing tank and causing poor image quality.

<About melamine resin particles>
The melamine resin particles used in the present invention preferably have an equivalent circle diameter (volume basis) of 1 μm or less. Moreover, 0.05 micrometer or more is preferable. If it is too large, it tends to remain as an aggregate when the melamine resin particles are adhered to the toner surface and tends to cause contamination of the material during printing, and if it is too small, the adhesion to the toner surface becomes too strong. On the contrary, when the toner charge amount is lowered, the fog tends to be deteriorated.

  As the resin used for the melamine resin particles, in addition to so-called melamine / formaldehyde condensation resin, melamine / urea / formaldehyde co-condensation resin, melamine / benzoguanamine / formaldehyde co-condensation resin, etc. can be targeted as long as melamine is the main component. . Among these, in the present invention, a melamine / formaldehyde condensation resin is preferable because a resin having a small equivalent circle diameter (volume basis) or a small standard deviation is easily obtained.

The reason why the melamine resin particles having a small equivalent circle diameter (volume basis) or a small standard deviation thereof are easily clarified at the time of external addition is not necessarily clear, but is presumed as follows.
When the equivalent circle diameter is small, it is considered that there is a large amount of residual electrolyte on the surface of the melamine resin particles during production, etc., and this generates aggregates due to excessive charging of the melamine resin particles by stirring during external addition Therefore, it is considered that the dispersibility of the toner is improved. Further, the fact that the equivalent circle diameters are uniform is considered that there is a space between the aggregates of the melamine resin particles, and therefore, it is considered that it is easy to unravel at the time of external addition.

  The amount of the melamine-based resin particles used is preferably 0.005 parts by mass or more and particularly preferably 0.100 parts by mass or more with respect to 100 parts by mass of the toner base particles from the viewpoint of suppressing fogging and blurring. Moreover, from a viewpoint of member contamination suppression, 0.010 mass part or less is preferable, and 0.035 mass part or less is especially preferable.

<About other external additives>
In addition, as the external additive, generally well-known external additives for toner can be used alone or in combination. Examples of external additives include inorganic particles such as silica particles, titania particles, aluminum oxide (alumina), zinc oxide, tin oxide, barium titanate, strontium titanate, hydrotalcite, etc. Organic resins such as organic acid salt particles such as zinc stearate and calcium stearate, methacrylic acid ester polymer particles, acrylic acid ester polymer particles, styrene-methacrylic acid ester copolymer particles, styrene-acrylic acid ester copolymer particles Particles and the like.

  In the present invention, it is preferable to use silica particles different from the colloidal silica fine particles as external additives used in the external addition step in addition to the external additives. Specifically, from the viewpoint of environmental stability, silica particles whose surface is subjected to a hydrophobizing treatment are preferable. The hydrophobization treatment agent and the treatment method are not particularly limited, and known ones are used, respectively. However, since higher hydrophobicity can be imparted, the treatment is performed with a silicone compound or a silicone treatment agent, for example, hexamethyldisilazane, Examples include dimethylpolysiloxane, dimethyldichlorosilane, methyltriethoxysilane, and octylsilane. Hexamethyldisilazane and dimethylpolysiloxane are preferred because higher hydrophobicity can be imparted, and dimethylpolysiloxane is particularly preferred.

<External addition process>
The external addition step of the external additive has at least two external addition steps. In the external addition step, the colloidal silica fine particles and the melamine resin particles are adhered or fixed to the surface of the toner base particles.
The method used in the external addition process is not particularly limited, and a mixer generally used for toner production can be used in each external addition process. Specifically, it is made by stirring and mixing with a mixer such as a Henschel mixer, a V-type blender, a Redige mixer, or a Q-mixer. The number of external addition steps is not particularly limited, but is usually 5 times or less, and preferably 3 times or less from the viewpoint of embedding the external additive in the toner base particles and reducing stress on the toner.

<Configuration and production method of toner base particles>
The volume median diameter of the toner base particles used in the production method of the present invention is not particularly limited, but is usually 3 μm or more, preferably 4 μm or more, and more preferably 5 μm or more. Moreover, it is 10 micrometers or less normally, it is preferable that it is 8 micrometers or less, and it is more preferable that it is 7 micrometers or less. If the volume median diameter of the toner is too large, the charge amount per unit mass will be small, and the possibility of fogging and toner scattering may increase.If it is too small, the charge amount per unit mass will be excessive. It may be easy to cause problems such as extreme image density reduction. The volume median diameter can be measured by the method described in Examples.

The present invention is most effective when the toner base particles are spherical.
Specifically, the effect is most manifested when the SF2 of the toner represented by the following formula (1) is 120 or less.

Formula (1): SF2 = (T2 / S) × (1 / 4π) × 100

In the above formula (1), S represents the projected area of the particle, and T represents the perimeter of the projected particle image.

If the SF2 is greater than 120, that is, there are many particle irregularities but has a complicated shape, the external additive will be buried in the concave portion of the toner at the time of addition and will not come out on the toner surface. It is difficult to express. SF2 can be measured by the method described in Examples.

  The constituent material of the toner of the present invention is not particularly limited, and includes at least a binder resin and a colorant, and includes a charge control agent, a wax, and other additives as necessary.

The production method of the toner base particles of the present invention is not limited, and a conventionally used method such as a pulverization method, a wet method, a method of spheroidizing the toner by a mechanical impact force, heat treatment or the like can be used. Examples of the wet method include a suspension polymerization method, an emulsion polymerization aggregation method, a dissolution suspension method, and an ester extension method.
In the pulverization method, a binder resin, a colorant, and other components as required are weighed and blended together and mixed. Examples of the mixing apparatus include a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, and a Nauter mixer.

  Next, the blended and mixed toner raw materials are melt-kneaded to melt the resins, and colorants and the like are dispersed therein. In the melt-kneading step, for example, a batch kneader such as a pressure kneader or a Banbury mixer, or a continuous kneader can be used. For the kneading machine, a single-screw or twin-screw extruder is used. For example, KTK type twin screw extruder manufactured by Kobe Steel, TEM type twin screw extruder manufactured by Toshiba Machine Co., Ltd., twin screw extruder manufactured by K.C.K. , Bus Co., Ltd. co-kneader. Further, the colored resin composition obtained by melt-kneading the toner raw material is rolled by a two-roll roll after melt-kneading and becomes a cooled product through a process of cooling by water cooling or the like.

The cooled product of the colored resin composition obtained above is then pulverized to a desired particle size in a pulverization step. In the pulverization step, first, coarse pulverization is performed with a crusher, a hammer mill, a feather mill or the like, and further, pulverization is performed with a kryptron system manufactured by Kawasaki Heavy Industries, Ltd., a super rotor manufactured by Nisshin Engineering Co., Ltd. or the like. After that, if necessary, the particles are classified using a classifier such as an inertia classification type elbow jet (manufactured by Nippon Steel Mining Co., Ltd.) or a centrifugal classification type turboplex (manufactured by Hosokawa Micron Co., Ltd.). obtain. Since the production method of the present invention works particularly suitably when the SF2 of the mother particle is 120 or less, a method conventionally used for obtaining the desired SF2 from the above steps, for example, spherical shapes such as meteole ambo, faculty, etc. The toner may be spheroidized by using a conversion device.
After obtaining the toner base particles, the toner can be obtained through a processing step of adding an external additive and, if necessary, other processing steps.

Examples of the wet method include an emulsion polymerization aggregation method, a suspension polymerization method, a dissolution suspension method, and the like, and any method may be used and is not particularly limited.
When producing toner mother particles by the emulsion polymerization aggregation method, usually a polymerization step of polymerizing polymer particles to obtain a polymer particle dispersion, a mixing step of mixing the polymer particle dispersion and the colorant particle dispersion, Aggregation step of adding a coagulant to the mixture and agglomerating to a predetermined particle size to obtain particle aggregates (aggregated particles), fusing step of overheating and fusing the agglomerated particles to form fused particles, and thereafter filtration and washing And a step of taking out toner mother particles such as a drying step.

In the present invention, as a method for producing a suspension polymerization toner, a coloring agent, a polymerization initiator, and, if necessary, additives such as a wax, a polar resin, a charge control agent and a crosslinking agent in the above-mentioned binder resin monomer Is added to prepare a monomer composition which 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, polymerization is performed by stirring to such an extent that the particle state is maintained and the sedimentation of the particles is prevented by the action of the dispersion stabilizer. These are collected by washing and filtration, and dried to obtain toner mother particles. After obtaining the toner base particles, the toner can be obtained through a processing step of adding an external additive and, if necessary, other processing steps.

  In the dissolution suspension method, a solution phase obtained by dissolving a binder resin in an organic solvent and adding and dispersing a colorant is dispersed in a water phase containing a dispersant by mechanical shearing force to form droplets. In this method, the organic solvent is removed from the droplets to produce toner particles.

  The ester elongation polymerization method mixes and emulsifies the oil phase in which wax, polyester resin, pigment, etc. are dispersed with the water phase to which the particle size control agent and surfactant are added, and creates oil droplets. This is a method for producing toner particles by converging and forming a polymer resin component on the surface of the toner oil droplets by extension reaction and removing the solvent inside the oil droplets.

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.
The binder resin used when the toner base particles are produced by a pulverization method includes polystyrene, a styrene-substituted homopolymer, a styrene copolymer, acrylic acid, methacrylic acid, polyester resin, polyamide resin, epoxy resin, Examples include xylene resins and silicone resins. These resins may be used alone or in combination.
Examples of the binder resin used when the toner base particles are produced by a polymerization method include vinyl polymerizable monomers capable of radical polymerization. Examples include styrene, styrene derivatives, acrylic polymerizable monomers, methacrylic polymerizable monomers, vinyl esters, vinyl ethers, vinyl ketones, and the like. These resins may be used alone or in combination of two or more.
As the 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) Any polymerizable monomer having no acidic group or basic group (hereinafter sometimes referred to as other monomer) can be used.

  Among the above-described polymerization methods, when the toner mother particles are produced using 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, when supplying the polymerizable monomer to the reaction system, each monomer 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 monomer constituting the binder resin is usually 0.05 parts by mass or more, preferably 0.5 parts by mass or more. Especially preferably, it is 1.0 mass part or more. Moreover, it is normally 10 mass parts or less, 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.

  When the binder resin is polymerized by an emulsion polymerization aggregation method, a known surfactant can be used as an emulsifier. As the surfactant, one or more surfactants selected from cationic surfactants, anionic surfactants, and nonionic surfactants 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.

  The amount of the emulsifier used in the production of the toner base particles using the emulsion polymerization aggregation method is not particularly limited, but is preferably 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer. . 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.

  The volume average particle diameter of the polymer primary particles obtained by the emulsion polymerization aggregation method is usually 0.02 μm or more, preferably 0.05 μm or more, particularly preferably 0.1 μm or more. Further, it is usually 3 μm or less, preferably 2 μm or less, particularly preferably 1 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.

  When the toner base particles are produced using the emulsion polymerization aggregation method, a known polymerization initiator can be used as necessary, and the polymerization initiators can be used alone or in combination of two or more. 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 case of producing toner base particles using the emulsion polymerization aggregation method, a known chain transfer agent can be used as necessary. Specific examples include t-dodecyl mercaptan, 2-mercaptoethanol, diisopropylxanthogen. , 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 mass based on the polymerizable monomer.

In the case of producing toner base particles using an emulsion polymerization aggregation method, a known suspension stabilizer can be used as necessary. 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. The suspension stabilizer is usually 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.

  The toner of the present invention may contain wax for imparting releasability. Any wax can be used as long as it has releasability.

  Specifically, for example, olefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene and copolymer polyethylene, paraffin waxes, ester waxes having a long chain aliphatic group such as behenyl behenate, montanate ester, stearyl stearate, etc. , Plant waxes such as hydrogenated castor oil, carnauba wax, ketones having long chain alkyl groups such as distearyl ketone, silicones having alkyl groups, higher fatty acids such as stearic acid, long chain aliphatic alcohols such as eicosanol, glycerin, Examples thereof include carboxylic acid esters of polyhydric alcohols obtained from polyhydric alcohols such as pentaerythritol and long chain fatty acids, or higher fatty acid amides such as partial esters, oleic acid amides and stearic acid amides, and low molecular weight polyesters.

  Among these waxes, in order to improve fixability, the melting point of the wax is usually 30 ° C. or higher, preferably 40 ° C. or higher, and particularly preferably 50 ° C. or higher. Moreover, it is 100 degrees C or less normally, 90 degrees C or less is more preferable, and 80 degrees C or less is especially preferable. If the melting point is too low, the wax may be exposed on the surface after fixing, and stickiness may occur. On the other hand, if the melting point is too high, the fixability at low temperatures may be poor.

  As the wax compound species, higher fatty acid ester waxes are preferable. Specific examples of the higher fatty acid ester wax include: behenyl behenate, stearyl stearate, stearate ester of pentaerythritol, montanic acid glyceride, etc. Esters are preferred. Moreover, as an alcohol component which comprises ester, a C1-C30 thing is preferable in the case of monohydric alcohol, and a C3-C10 thing is preferable in the case of a polyhydric alcohol. The above waxes may be used alone or in combination. Further, the melting point of the wax compound can be appropriately selected depending on the fixing temperature for fixing the toner.

  In the present invention, when the wax is contained, the amount of the wax is not particularly limited, but is usually 1 part by mass or more, preferably 2 parts by mass or more, particularly preferably 5 parts by mass with respect to 100 parts by mass of the toner. More than a part. Moreover, it is 40 mass parts or less normally, Preferably it is 35 mass parts or less, Most preferably, it is 30 mass parts or less. If the wax content in the toner is too low, performance such as high-temperature offset may not be sufficient, while if it is too high, the blocking resistance may not be sufficient, or the wax may leak from the toner and contaminate the device. Sometimes.

  A known colorant can be arbitrarily used as the colorant of the present invention. Specific examples of the colorant 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 the state of being dispersed in water in the presence of an emulsifier, and the volume average particle size of the colorant particles is usually 0.01 μm or more, preferably 0.05 μm or more. Further, it is usually 3 μm or less, preferably 1 μm.

  In the present invention, a charge control agent may be used as necessary. When the charge control agent is used, any known one can be used alone or in combination. For example, azine series such as quaternary ammonium salt, nigrosine, processed nigrosine, and alkyl nigrosine as a positive charge control agent. Examples include black dyes, processed nigrosine compounds, guanidine compounds, triphenylsulfonium compounds, resin-based charge control agents, amide group-containing compounds, and basic / electron-donating metal substances. Aromatic oxycarboxylics as negatively chargeable charge control agents Acid-based, aromatic dicarboxylic acid metal chelates, monoazo metal-containing complex compounds, organic acid metal salts, metal-containing dyes, diphenylhydroxy complex compounds, iron-containing azo compounds, home appliance control agents for emulsion polymerization, various metal oxycarboxylic acids Complex compounds, calixarene compounds, phenolic compounds, resin-based charge control agents, naphtha Lumpur compounds and their metal salts, urethane compounds, and acidic or electron-withdrawing organic substances.

  In addition, when the toner of the present invention is used as a toner other than a black toner in a color toner or a full color toner, it is preferable to use a charge control agent that is colorless or light-colored and does not impair the color tone of the toner. As a charge control agent, a quaternary ammonium salt compound, as a negative charge control agent, a metal salt with zinc or aluminum of salicylic acid or alkylsalicylic acid, a metal complex, a metal salt of benzylic acid, a metal complex, an amide compound, Preference is given to hydroxynaphthalene compounds such as phenolic compounds, naphthol compounds, phenolamide compounds, and 4,4′-methylenebis [2- [N- (4-chlorophenyl) amide] -3-hydroxynaphthalene].

  In the toner of the present invention, when a charge control agent is contained in the toner using an 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 polymer primary particles and a colorant. Or the like in the agglomeration step, or after the polymer primary particles and the colorant are agglomerated 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 toner of the present invention, the amount of electrolyte added varies depending on the type of electrolyte, target particle size, etc., but is usually 0.05 parts by mass or more with respect to 100 parts by mass of the solid component of the mixed dispersion. .1 part by mass or more is preferable. Moreover, it is 25 mass parts or less normally, 15 mass parts or less are preferable, and especially 10 mass parts or less are preferable. If the addition amount is too small, the progress of the agglutination reaction is delayed, and fine powders of 1 μm or less remain even after the agglomeration reaction, and the average particle size of the obtained particle aggregate may not reach the target particle size. On the other hand, if the amount is too large, rapid aggregation tends to occur and it is difficult to control the particle size, and the resulting aggregated particles may include problems such as inclusion of coarse powder or irregular shapes. The aggregation temperature in the case of performing aggregation by adding an electrolyte is usually 20 ° C. or higher, preferably 30 ° C. or higher. Moreover, it is 70 degrees C or less normally, Preferably it is 60 degrees C or less. The aggregation temperature in the case of performing aggregation only by heating without using an electrolyte is usually (Tg-20) ° C. or higher, preferably (Tg-10) ° C. or higher, where Tg is the glass transition temperature of the polymer primary particles. . Moreover, it is below Tg normally and is below (Tg-5) degreeC.

  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. preferable. The temperature rise until reaching the predetermined temperature may be raised at a constant rate, or may be raised stepwise.

  If necessary, particles having adhered or fixed resin particles may be formed on the surface of the particle aggregate after the above-described aggregation treatment. In some cases, the chargeability and heat resistance of the obtained toner can be improved by attaching or fixing the resin particles whose properties are controlled to the surface of the particle aggregate, and the effect of the present invention can be further enhanced. .

  When resin particles having a glass transition temperature higher than that of the polymer primary particles are used as the resin particles, it is preferable because blocking resistance can be further improved without impairing fixing properties. The volume average particle diameter of the resin particles is usually 0.02 μm or more, preferably 0.05 μm or more. Moreover, it is 3 micrometers or less normally, and 1.5 micrometers or less are preferable. As the resin particles, those obtained by emulsion polymerization of monomers similar to the polymerizable monomers used for the above-mentioned polymer primary particles can be used. Resin particles are usually used as a dispersion dispersed in water or a liquid mainly composed of water with 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 the resin 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 aging step is usually at least Tg of the polymer primary particles, preferably at least 5 ° C higher than Tg, and usually at most 80 ° C higher than Tg, preferably at most 50 ° C higher than Tg. 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 preferred.

  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. The addition amount in the case of adding the surfactant is not limited, but is usually 0.1 parts by mass or more, preferably 1 part by mass or more, particularly preferably 3 parts by mass or more with respect to 100 parts by mass of the solid component of the mixed dispersion. It is. Moreover, it is 20 mass parts or less normally, Preferably it is 15 mass parts or less, Most preferably, it is 10 mass parts 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 obtained particles are subjected to solid-liquid separation by a known method, the particles are collected, and washed and dried as necessary to obtain target toner mother particles.

  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”, and “%” means “% by mass”.

<Measurement method of silica particle size>
The volume average diameter (Mv) and number average diameter (Mn), volume median diameter, and number median diameter of the sol-gel silica particles are those manufactured by Nikkiso Co., Ltd., Model: Microtrac Nanotrac 150 (hereinafter abbreviated as “Nanotrack”). In accordance with the instruction manual of the nanotrack, the company's analysis software Microtrac Particle Analyzer Ver10.1.2. Using −019EE, ion-exchanged water having an electric conductivity of 0.5 μS / cm was used as a dispersion medium, and measurement was performed by the method described in the instruction manual under the following conditions or the following conditions, respectively.
Solvent refractive index: 1.333
-Measurement time: 100 seconds-Number of measurements: 1 time-Particle refractive index: 1.59
-Permeability: Transmission-Shape: True spherical shape-Density: 1.04

<Method for Measuring Volume Median Diameter (Dv50) of Toner Particles>
Use Beckman Coulter's Multisizer III (aperture diameter 100 μm) (hereinafter abbreviated as “Multisizer”), use the company's Isoton II as the dispersion medium, and disperse so that the dispersoid concentration is 0.03% by mass. And measured. The measurement particle diameter range is from 2.00 to 64.00 μm, and this range is discretized into 256 divisions so as to be equidistant on a logarithmic scale, and the volume calculated based on the statistical values on the basis of the volume is the volume. The median diameter (Dv50) was used.

<Measurement method of SF2>
An electron micrograph at a magnification of 1000 × of toner particles is subjected to image analysis with Luzex-F (manufactured by Nireco) to determine the projected area (S) of the particles and the peripheral length (T) of the projected toner image. SF2 is obtained by the following equation (1).
Formula (1): SF2 = (T2 / S) × (1 / 4π) × 100

<Preparation of wax dispersion A1>
Wax 1 (HiMic-1090 (manufactured by Nippon Seiwa Co., Ltd.), melting point 87 ° C.) 29.7 parts, decaglycerin decabehenate (acid value 3.2, hydroxyl value 27) 0.3 part, 20% dodecylbenzenesulfonic acid A sodium aqueous solution (Daiichi Kogyo Seiyaku Co., Ltd., Neogen S20D, hereinafter abbreviated as 20% DBS aqueous solution) 2.8 parts of aqueous solution and 67.3 parts of demineralized water were added and heated to 100 ° C., and a homogenizer with a pressure circulation line ( Primary circulation emulsification was performed under a pressure of 10 MPa using a LAB 60-10TBS type manufactured by Gorin. 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 215 nm.

<Preparation of wax dispersion A2>
20 parts by weight of paraffin wax (HNP9: Nippon Seiwa Co., Ltd., melting point: 77 ° C.) was added to a 20% by weight aqueous solution of anionic surfactant (Neogen S-20D: sodium dodecylbenzenesulfonate aqueous solution, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., “20% A wax dispersion A2 was prepared by emulsification under high-pressure shearing in addition to 1.44 parts by mass of ion-exchanged water together with 1.44 parts by mass of “DBS aqueous solution”.
The volume median diameter of the wax dispersion was 250 μm.

<Preparation of polymer primary particle dispersion B1>
A reactor equipped with a stirrer (three blades), a heating / cooling device, a concentrating device, and each raw material / auxiliary charging device was charged with 36.3 parts of the wax dispersion A1 and 231 parts of demineralized water and stirred. The temperature was raised to 90 ° C. under a nitrogen stream.
Then, the mixture of the following "polymerizable monomers etc.-1" and "emulsifier aqueous solution-1" was added over 5 hours, continuing stirring of the said liquid. The time at which this mixture was started to be dropped was designated as “polymerization start”, and the following “initiator aqueous solution-1” 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 initiator aqueous solution-1 ”was added over 2 hours, and the internal temperature was maintained at 90 ° C. for 1 hour while continuing stirring.
[Polymerizable monomers, etc.-1]
Styrene 75.9 parts Butyl acrylate 24.1 parts Acrylic acid 1.2 parts Hexanediol diacrylate 0.6 parts Trichlorobromomethane 1.0 part [Emulsifier aqueous solution-1]
20% DBS aqueous solution 1.0 part Demineralized water 66.9 parts [Initiator aqueous solution-1]
8% by mass aqueous hydrogen peroxide solution 15.5 parts 8% by mass L (+)-ascorbic acid aqueous solution 15.5 parts [additional aqueous initiator solution-1]
8 mass% L (+)-ascorbic acid aqueous solution 14.2 parts

After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle dispersion B1. The volume average diameter (Mv) measured using Microtrac UPA was 239 nm, and the solid content concentration was 22.3 mass%.

<Preparation of polymer primary particle dispersion B2>
A reactor equipped with a stirrer (three blades), a heating / cooling device, and a raw material / auxiliary charging device was charged with 36.1 parts by weight of the wax emulsion A2 and 259 parts by weight of ion-exchanged water. The temperature was raised to 90 ° C. under an air stream.
Then, the mixture of the following "polymerizable monomers etc.-2" and "emulsifier aqueous solution-2" was added there over 5 hours, continuing stirring of the said liquid. The time at which the mixture was started to drop was defined as “polymerization start”, and 30 minutes after “polymerization start”, [Initiator aqueous solution-2] was added over 4.5 hours in parallel with the above operation. After the addition of the mixture and [Initiator aqueous solution-2] was completed, [Additional initiator aqueous solution-2] was added over 2 hours. Stirring was further continued after the addition of [Initiator aqueous solution-2], and the internal temperature was maintained at 90 ° C. for 1 hour.
[Polymerizable monomers, etc.-2]
Styrene 76.75 parts by mass Butyl acrylate 23.25 parts by mass Acrylic acid 1.5 parts by mass Hexanediol diacrylate 0.7 parts by mass Trichlorobromomethane 1.0 part by mass [Emulsifier aqueous solution-2]
20% DBS aqueous solution 1.0 part by mass Ion-exchanged water 67.1 parts by mass [Initiator aqueous solution-2]
8% by mass aqueous hydrogen peroxide solution 15.52 parts by mass 8% by mass L (+)-ascorbic acid aqueous solution 15.52 parts by mass [Additional initiator aqueous solution-2]
8% by mass L (+)-ascorbic acid aqueous solution 14.21 parts by mass

After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle emulsion B2. The volume average particle diameter (Mv) measured using Microtrac UPA was 258 nm, and the solid content concentration was 20.4% by mass.

<Manufacture of toner mother particle A>
Polymer primary particle dispersion B1 (for core) 80 parts as solid content Polymer primary particle dispersion B2 (for shell) 20 parts as solid content Cyan pigment dispersion (EP750, manufactured by Dainichi Seika Co., Ltd.) Colorant 4 as solid content .4 parts 20% DBS aqueous solution 0.1 parts as solid content Toner base particles A were produced by the following procedure using the above components.

  Polymer primary particle dispersion B1 (core) in a mixer (volume 12 liters, inner diameter 208 mm, height 355 mm) equipped with a stirrer (double helical blade), heating / cooling device, concentrator, and raw material / auxiliary charging device And 20% DBS aqueous solution, and uniformly mixed for 5 minutes at an internal temperature of 12 ° C. Subsequently, while stirring at an internal temperature of 12 ° C., 0.52 part of FeSO4 · 7H2O was added as a 5% aqueous solution of ferrous sulfate over 5 minutes, and then the black colorant dispersion was added over 5 minutes. The mixture was uniformly mixed at an internal temperature of 12 ° C., and a 0.5% aluminum sulfate aqueous solution was added dropwise under the same conditions (the solid content relative to the resin solid content was 0.10 parts). Thereafter, the temperature was raised to 53 ° C. over 75 minutes, and further raised to 56 ° C. over 170 minutes. Here, when the volume median diameter (Dv50) was measured using a multisizer, it was 6.7 μm. Thereafter, polymer primary particle dispersion B2 (for shell) is added over 3 minutes and held for 60 minutes, followed by addition of 20% DBS aqueous solution (6 parts as solids) over 10 minutes, followed by 30 The temperature was raised to 95 ° C over a period of time, and stirring was continued over 120 minutes until the average circularity reached 0.970. Then, it cooled to 30 degreeC over 30 minutes, and obtained the slurry. At this time, Dv50 of the particles was 7.2 μm, and the average circularity was 0.971.

  This slurry was subjected to suction filtration with an aspirator using filter paper of type 5 C (No. 5C manufactured by Toyo Roshi Kaisha, Ltd.). The cake remaining on the filter paper is transferred to a stainless steel container having an internal volume of 10 L equipped with a stirrer (propeller blade), added with 8 kg of ion-exchanged water having an electric conductivity of 1 μS / cm, and uniformly dispersed by stirring at 50 rpm. Stirred for 30 minutes. Then, suction filtration is performed with an aspirator again using filter paper of 5 types C (Toyo Filter Paper Co., Ltd. No5C), and the solid matter remaining on the filter paper is again equipped with a stirrer (propeller blade) and has an electric conductivity of 1 μS / cm. It was transferred to a 10 L container with 8 kg of ion-exchanged water, and evenly dispersed by stirring at 50 rpm and kept stirring for 30 minutes. When this process was repeated 5 times, the electrical conductivity of the filtrate was 2 μS / cm.

  The obtained cake was spread on a stainless steel pad 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 C.

[Example 1]
<Manufacture of toner A>
1 part of silica particles A (colloidal silica, volume average primary particle size 10 nm, hydrophobized surface with silane coupling agent and organosilazane), melamine resin particles A (volume average) with respect to base particles A (100 parts) 0.05 part of primary particle size 200 nm), 0.8 part of silica particle B (colloidal silica, volume average primary particle size 110 nm, hexamethyldisilazane treatment), silica particle C (fumed silica, volume average primary particle size) Toner A was obtained by adding 0.8 part of 80 nm, silicone oil surface treatment) and stirring and mixing at 1500 rpm for 15 minutes with a Henschel mixer.

[Example 2]
<Manufacture of toner B>
In Example 1, toner B was obtained in the same manner as in Example 1 except that the added part of silica particle A was 0.8 part and the added part of melamine resin particle A was 0.02 part.

Example 3
<Manufacture of toner C>
In Example 2, Toner C was obtained in the same manner as in Example 2 except that 0.26 part of titania particles a (volume average primary particle size 14 nm) was added.

Example 4
<Manufacture of toner D>
In Example 2, Toner D was obtained in the same manner as in Example 2 except that the added part of silica particle A was 0.6 part and the added part of melamine resin particle A was 0.05 part.

Example 5
<Manufacture of toner E>
In Example 4, Toner D was obtained in the same manner as in Example 4 except that the number of added silica particles A was 1.2 parts.

Example 6
<Manufacture of toner F>
In Example 4, Toner F was obtained in the same manner as in Example 4 except that the number of added parts of silica particles A was 0.8 part.

[Comparative Example 1]
<Manufacture of toner G>
In Example 1, a toner G was obtained in the same manner as in Example 1 except that the number of added melamine resin particles A was 0.

[Comparative Example 2]
<Manufacture of toner H>
A toner H was obtained in the same manner as in Comparative Example 1 except that the number of added parts of the silica fine particles A was 0.8 in Comparative Example 1.

[Comparative Example 3]
<Manufacture of Toner I>
In Comparative Example 2, Toner I was obtained in the same manner as Comparative Example 2, except that 0.26 part of titania particles a was added.

[Comparative Example 4]
<Manufacture of toner J>
In Comparative Example 3, the addition part of silica particle A is 0 part, 0.2 part of melamine resin particles, and 0.44 part of silica particles D (fumed silica, volume average primary particle size 12 nm, silicone oil treatment) are added. A toner J was obtained in the same manner as in Comparative Example 3 except that.

[Comparative Example 5]
<Manufacture of toner K>
In Comparative Example 4, the toner was prepared in the same manner as in Comparative Example 4, except that the added part of silica particle B was 1.6 parts, the added part of silica particle C was 0 part, and the added part of silica particle D was 0.585 part. K was obtained.

[Comparative Example 6]
<Manufacture of toner L>
Example 1 was the same as Example 1 except that the number of parts added of silica particles A was 0 parts, and 0.8 parts of silica particles E (fumed silica, volume average primary particle size 7 nm, silicone oil treatment) were added. Thus, toner L was obtained.

[Comparative Example 7]
<Manufacture of toner M>
Comparative Example 6 is the same as Comparative Example 6 except that 0.02 part of the melamine resin particles are added and 0.8 part of silica particles F (colloidal silica, volume average primary particle size 10 nm, hexamethyldisilazane treatment) is added. In the same manner as above, a toner M was obtained.

[Comparative Example 8]
<Manufacture of toner N>
In Comparative Example 7, a toner N was obtained in the same manner as in Comparative Example 7, except that the added part of melamine resin particles A was 0.05 part.

[Comparative Example 9]
<Manufacture of toner O>
In Comparative Example 7, Toner O was obtained in the same manner as in Comparative Example 7 except that the number of added melamine resin particles A was 0.1 part.

<Toner evaluation method using live-action test>
The resulting toner is a non-magnetic one component (using an organic photoreceptor), roller (PCR) charging, rubber development roller contact development system, development speed 164 mm / second, tandem system, belt transport system, direct transfer system, blade drum Using a cleaning method, a photograph was taken with a 600 dpi full color printer having a guaranteed life of 30,000 sheets at a 5% printing rate.

<Evaluation method of fog>
In an environment of 25 ° C. and 50%, a 1% printing rate chart was intermittently printed up to 10,000 sheets, and then left in a printer at 28 ° C. and 80% environment for one day. Thereafter, printing was performed as follows, and fog was evaluated. The toner adhering to the white background portion of the photosensitive drum before the transfer process to paper at the time of printing was copied with a mending tape (manufactured by Sumitomo 3M Co., Ltd.) and pasted on 80 g / m 2 of printing paper. Further, after a mending tape was directly applied to the same sheet for comparison, the color difference ΔE between the two was measured with a spectrocolorimetric densitometer X-Rite 939 (manufactured by X-Rite) to evaluate fog. Judgment criteria were as follows.
◎: ΔE is less than 1 ○: ΔE is 1 or more and less than 2 ×: ΔE is 2 or more

<Evaluation method of streaks>
After printing 1% coverage chart up to 10,000 sheets intermittently in an environment of 25 ° C and 50%, print a 100% coverage solid image chart and check for the occurrence of image defects such as white lines in the printing direction. evaluated. Judgment criteria were as follows.
○: There is no image defect such as a white line, and the image quality is good.
×: White lines and other streaks are seen on the image, and an image defect has occurred.

<Method for evaluating afterimage>
After printing 1% coverage chart up to 10,000 sheets intermittently in an environment of 25 ° C and 50%, a specific image is created at the leading edge of the printing direction, and after that image a solid image and a blank image Were used for each print direction, and it was evaluated whether the image at the front end portion was generated as a residual image in the solid image or the blank paper portion in the print direction.
○: No image lag and good image quality.
X: An afterimage of the front end is seen at the rear end of the chart, and an image defect has occurred.

<Evaluation method of fluidity>
The toner fluidity was evaluated using a powder tester (manufactured by Hosokawa Micron Corporation) in an environment of 25 ° C. and 50%. The sieve has openings of 150 μm, 75 μm, and 45 μm, and 4 g of toner is placed on the sieve, and measurement is started under conditions of vibration time 15 seconds / amplitude 0.2 mm. After the vibration is stopped, the toner remaining on each sieve is weighed, and the fluidity is obtained from the degree of aggregation according to the following formulas (4) to (8).

Formula (4): (a) = (Mass of residual toner on the upper screen / 4 g) × 100

Formula (5): (b) = (Mass of residual toner on sieve in middle stage / 4 g) × 100 × 0.6

Formula (6): (c) = (Mass of residual toner on upper screen / 4 g) × 100 × 0.2

Formula (7): Aggregation degree = (a) + (b) + (c)

Formula (8): fluidity = 100-cohesion degree

From the obtained numerical value of fluidity, superiority or inferiority was determined according to the following criteria.
○: 61% or more △: 51% or more, less than 60% ×: less than 50%

  From this result, it was found that all characteristics were satisfied only when specific colloidal silica fine particles and melamine resin particles were used.

Claims (6)

A toner for developing an electrostatic image having at least two kinds of external additives on the surface of the toner base particles,
One of the two or more external additives is colloidal silica fine particles hydrophobized using a silane coupling agent and organosilazane, and the other one is melamine resin particles,
A toner for developing an electrostatic charge image, wherein the colloidal silica fine particles have a volume average particle diameter of 20 nm or less.
2. The toner for developing an electrostatic charge image according to claim 1, wherein the amount of the colloidal silica fine particles added to 100 parts of the toner base particles is 0.6 part or more and 1.0 part or less.
3. The electrostatic image developing toner according to claim 1, wherein the number of added parts of the melamine-based resin fine particles to 100 parts of the toner base particles is 0.005 part or more and 0.100 part or less. 4.
4. The electrostatic charge image according to claim 1, wherein the number of added melamine-based resin fine particles with respect to 100 parts of the toner base particles is 0.010 part or more and 0.035 part or less. 5. Development toner.
The positively charged toner for developing electrostatic images according to claim 1, wherein SF2 of the toner base particles represented by the following formula (1) is 120 or less.

Formula (1): SF2 = (T ² / S) × (1 / 4π) × 100

(In the above equation (1), S represents the projected area of the particle, and T represents the perimeter of the projected particle image.)
  6. The toner for developing an electrostatic charge image according to claim 1, wherein the toner base particles contain at least a binder resin and a colorant.