JP2013105153A - Toner for electrostatic charge image development and method for manufacturing toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide toner for electrostatic charge image development capable of improving fogging without contaminating members such as a charging roller and a charging blade under low-temperature and low-humidity environment.SOLUTION: There is provided toner for electrostatic charge image development obtained through a process of adding an external additive to toner base particles containing a binder resin, a pigment and a wax. The toner satisfies the following (A) to (D): (A) ΔBET(m/g), which is the difference between the BET (m/g) of the toner base particle and the BET (m/g) of the toner, is 1.00 or more and 2.00 or less, (B) the process of adding the external additive is a multistage process, (C) the external additive contains silica, and (D) Mn-Mn, which is the difference between the average primary particle diameter Mn(nm) of silica particles contained in the external additive added at the first stage of the addition process and the average primary particle diameter Mn(nm) of the silica particles added at the final stage, is 0 nm or more and 2 30 nm or less.

Description

  The present invention relates to an electrostatic charge image developing 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 to reducing the particle size of the toner as described above, various studies have been made to achieve durability and fluidity to obtain a stable high image quality and to control the chargeability.
For example, as a study in the external addition process, in order to achieve both the durability and fluidity of the toner, a silica having a large particle size is added to the first stage of external addition, and a silica having a particle size smaller than the number average particle size. There is known a technique for externally adding to the final stage (Patent Document 1). According to this technology, the large particle size silica exhibits a spacer effect without causing contamination of the charging roller due to desorption, and it is possible to prevent a decrease in fluidity due to the embedding of the small particle size silica in the toner base particles. .

JP 2004-212508 A

In the technique of Patent Document 1, attention should be paid to the amount of the small particle size silica added to the final stage and the particle size difference from the large particle size silica. This is because there is a great concern when each parameter deviates from the optimum point as shown below.
If the amount of silica added to the final stage is excessive, charging roller contamination due to fogging or free external additives may occur due to uneven charging of silica that is not crushed. If the amount is too small, the cleaning effect in the vicinity of the cleaning blade due to the free external additive will not be manifested, and the charging roller will be contaminated by the toner passing through the blade, and the toner fluidity will deteriorate significantly in the latter half of the life. Fixing is promoted, which may result in a linear image defect. In addition, if the particle size difference between the silica added to the final stage and the silica added externally to the first stage is too large, the embedding of the small particle size silica becomes prominent, and the spacer effect due to the large particle size silica is reduced, Paper fog occurs. If it is too small, a large number of spherical silica particles having the same particle diameter are in close contact with each other, and the effect of suppressing the phenomenon in which drag is generated by the silica far from the blade is reduced.

That is, a technique for appropriately controlling the durability, fluidity, and chargeability of the toner and achieving both contamination of the charging roller and fogging has not yet been provided.
The present invention has been made in view of such a problem, and the problem is to develop a toner for developing an electrostatic charge image that does not contaminate members such as a charging roller and a charging blade in a low-temperature and low-humidity environment and also has good fog. It is to provide.

The present inventor has repeatedly studied to solve the above-mentioned problems, and externally adds silica having physical properties within a specific range and silica having a particle diameter different from that of the silica particles to a specific number of parts and a specific stage. I found out to solve it. The present invention is based on this finding, and the gist of the present invention is as follows.
1. An electrostatic charge image developing comprising: a toner obtained through a step of adding an external additive to toner base particles containing a binder resin, a colorant, and a wax, wherein the toner satisfies the following (A) to (D): Toner.
(A) ΔBET (m ² / g), which is the difference between BET (m ² / g) of the toner base particles and BET (m ² / g) of the toner, is 1.00 or more and 2.00 or less ( B) The step of adding the external additive is a multi-stage step (C) The external additive contains silica (D) The silica particles contained in the external additive added in the first stage of the addition step _1. Mn ₁ -Mn _f which is the difference between the average primary particle size Mn ₁ (nm) of the silica and the average primary particle size Mn _f (nm) of the silica particles added in the final stage is greater than 0 nm and 30 nm or less. The external addition process is a multistage process, and the amount of the external additive added in the final stage of the external addition process is 60% by mass or more and 80% by mass or less based on the total amount of the external additive. The above 1. The toner for developing an electrostatic charge image according to 1.
3. 2. The external additive burying rate (%) represented by the following formula is 20% or more and 55% or less after completion of the final stage of the external addition step. The toner for developing an electrostatic charge image according to 1.
(External additive burying rate) = ((I) total specific surface area of external additive embedded in mother particles) × 100 / ((II) total specific surface area of added external additive)
(I) = {(a1 + b1) / (a2 + b2) −c} × 100
(II) = (a1 + b1) / (a2 + b2) -d
[In the above formula,
a1 represents the surface area (m ² ) of the toner base particles,
a2 represents the input amount (g) of toner base particles,
b1 represents the total surface area (m ² ) of the external additives introduced up to the final stage,
b2 represents the input amount (g) of the external additive to be added up to the final stage,
c is the measured BET value of the toner after the final stage (m ² / g)
d represents the BET value (m ² / g) of the toner base particles after the final stage.
d is a value calculated by dividing the measured BET value (m ² / g) of the toner base particles by the sum of the input amount (g) of the external additive and base particles to be introduced up to the final stage. ]
4). In the external addition step, the silica particles used in the first stage are silica particles of 35 nm or more and 150 nm or less. The toner for developing an electrostatic charge image according to 1.

  According to the present invention, in a low-temperature and low-humidity environment, by reducing contamination of members such as a charging roller and a charging blade, image defects due to member contamination can be suppressed, and paper fogging can also be suppressed well. .

In the toner of the present invention, ΔBET, which is the difference between the BET of the toner base particles and the BET of the toner, is 1.
00m ² / g or more 2.00m ² / g or less. 1.10 m ² / g or more is preferable.
20 m ² / g or more is particularly preferable. Moreover, 1.90 m < ² > / g or less is preferable and 1.80 m < ² > / g or less is especially preferable. If ΔBET is too small, the cleaning effect in the vicinity of the cleaning blade by the free external additive is not exhibited, and the charging roller may be contaminated by the toner passing through the blade. On the other hand, if it is too large, the external additive may be excessively detached from the toner base particles, and charging roller contamination may occur due to the free external additive passing through the blade. The BET of the toner base particles and the toner is measured by the method described in the examples, and ΔBET is calculated by subtracting the BET of the toner base particles from the BET of the toner.

The toner of the present invention is obtained through a step of adding the external additive, which is a multi-step process of two or more steps (sometimes referred to as an external addition step).
The silica particles used in the present invention are typically used in a state where they are adhered or fixed to the toner surface as an external additive for the toner. Mn ₁ − which is the difference between the average primary particle diameter Mn ₁ (nm) of the silica particles added to the first stage of the addition step and the average primary particle diameter Mn _f (nm) of the silica particles added to the final stage. Mn _f is greater than 0 nm and 30 nm or less. The lower limit of Mn ₁ -Mn _f is preferably 10 nm or more, more preferably 15 nm or more, still more preferably 20 nm or more, particularly preferably 25 nm or more, and most preferably 28 nm or more.

When Mn ₁ -Mn _f is too large, the embedding of silica particles having an average primary particle size of Mn _f becomes remarkable, the spacer effect due to the silica particles having an average primary particle size of Mn ₁ is reduced, and paper fogging occurs. Arise. If Mn ₁ -Mn _f is too small, the necessary cleaning effect in the vicinity of the blade due to the difference in the particle size of the silica particles is not exhibited, and the charging roller may be contaminated by the toner passing through the blade. The average primary particle size of the silica particles is measured by the method described in the examples.

  In the toner of the present invention, the amount of the external additive externally added in the final stage of the external addition step is not particularly limited, but the lower limit is usually 60% by mass or more based on the total amount of the external additive, preferably 65% by mass or more. On the other hand, an upper limit is 80 mass% or less, Preferably it is 75 mass% or less. When the amount of the external additive added is small, the cleaning effect in the vicinity of the cleaning blade by the free external additive is not exhibited, and the charging roller may be contaminated by the blade slipping toner. If the amount is too large, the external additive may be excessively detached from the toner base particles, and charging roller contamination may occur due to the free external additive passing through the blade.

Further, the surface area of the external additive externally added in the final stage is not particularly limited, but in order to exert the effect of the external additive added in the final stage detailed above, all external additives It is preferably 70% or more of the surface area, more preferably 75% or more. On the other hand, the surface area of the external additive externally added in the final stage is 85% or less of the total surface area of the external additive. It is preferable that
The surface areas of the toner base particles and the toner are determined by the method described in the examples.

In the toner of the present invention, the burying rate of the external additive on the surface of the base particle after the final step of adding the external additive is not particularly limited, but the lower limit is usually 20% or more, and 25% or more. Preferably, 30% or more is particularly preferable. On the other hand, the upper limit is usually 55% or less, preferably 50% or less, and particularly preferably 45% or less.
The external additive burying rate is obtained by the following formula.

(External additive burying rate) = ((I) total specific surface area of external additive embedded in mother particles) × 100 / ((II) total specific surface area of added external additive)
(I) = {(a1 + b1) / (a2 + b2) −c} × 100
(II) = (a1 + b1) / (a2 + b2) -d
[In the above formula,
a1 represents the surface area (m ² ) of the toner base particles,
a2 represents the input amount (g) of toner base particles,
b1 represents the total surface area (m ² ) of the external additives introduced up to the final stage,
b2 represents the input amount (g) of the external additive to be added up to the final stage,
c is the measured BET value of the toner after the final stage (m ² / g)
d represents the BET value (m ² / g) of the toner base particles after the final stage.
d is a value calculated by dividing the measured BET value (m ² / g) of the toner base particles by the sum of the input amount (g) of the external additive and toner base particles to be introduced up to the final stage. ]

When the external additive burying rate is large, the required fluidity cannot be obtained, the charging roller contamination by the blade slipping toner, the mutual friction between the external additives is insufficient, and the expected charge amount cannot be obtained. There is concern about the deterioration of fog. If it is too small, the external additives aggregate together, and the charge amount distribution becomes broad due to contamination of the charging roller by the aggregate and excessive charging friction, and the fog may be deteriorated.
The BET of the toner base particles and the toner in the above formula is measured by the method described in the examples in the same manner as ΔBET.

The average primary particle diameter of the silica particles used in the first stage in the present invention is not particularly limited as long as the relationship of Mn ₁ -Mn _f is satisfied, but the lower limit is usually 35 nm or more, preferably 37 nm or more, and 40 nm. The above is particularly preferable. On the other hand, the upper limit is usually 150 nm or less, preferably 100 nm or less, and particularly preferably 80 nm or less. If the average primary particle size used in the first stage is too small, a sufficient spacer effect cannot be obtained, and embedding of the small particle size external additive added in the final stage into the toner base particles causes printing durability. In the latter half, fogging or blurring may occur. On the other hand, if it is too large, it may be difficult to adhere to the toner base particles, and member contamination due to detachment may occur. The average primary particle size of the silica particles is measured by the method described in the examples.

In addition, before the first stage external addition and after the final stage external addition, the external addition is appropriately performed for the purpose of imparting chargeability and fluidity and suppressing the release of the external additive from the toner base particles as long as the effects of the present invention are not impaired. Etc. may be performed.
In the present invention, the silica particles used in the first stage and the final stage of the external addition step are not particularly limited as long as they do not affect the effect of the present invention. It is preferable from the viewpoint of stability. The treatment agent and the treatment method are not particularly limited, and known ones are used. However, since higher hydrophobicity can be imparted, treatment with a silicone compound or a silicone treatment agent is performed, for example, hexamethyldisilazane, dimethylpolysiloxane. Examples include siloxane, dimethyldichlorosilane, methyltriethoxysilane, and octylsilane. Hexamethyldisilazane and dimethylpolysiloxane are preferred because higher hydrophobicity can be imparted, and dimethylpolysiloxane is particularly preferred.

  The volume median diameter of the toner base particles of the present invention is not particularly limited, but is usually 3 μm or more, preferably 4 μm or more, more preferably 5 μm or more, and usually 10 μm or less. Yes, it is preferably 8 μm or less, and more preferably 7 μm or less If the volume median diameter of the toner is too large, the charge amount per unit weight tends to decrease, and fogging and toner scattering occur. If the amount is too small, the amount of charge per unit weight tends to be excessive, and problems such as extreme reduction in image density may occur. It is measured by the method described.

The average circularity of the toner base particles of the present invention is usually 0.955 or more and preferably 0.960 or more. Moreover, it is 0.985 or less normally, and it is preferable that it is 0.980 or less. If the circularity is too large, slipping in the cleaning part is likely to occur, and the image may be defective. On the other hand, if the circularity is too small, when the inorganic particles roll on the surface of the mother particles due to agitation by printing durability, the mother particles The effect of the present invention may not be maintained until the end. The circularity of the toner base particles of the present invention is measured by the method described in the 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.

The pulverization method will be described later. In the case of the pulverization method, a predetermined amount of a binder resin, a colorant, and other components as required are mixed 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 disperse the colorant and the like 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. Further, the toner may be spheroidized using a conventionally used method.

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 a suspension polymerization method, an emulsion polymerization aggregation method, a dissolution suspension method, and the like, and any method may be used without any particular limitation.

  In the present invention, as a method for producing a suspension polymerization toner, a coloring agent, a polymerization initiator, and, if necessary, a wax, a polar resin, a charge control agent, a crosslinking agent, etc. in the above-mentioned binder resin monomer. 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, 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 production method of the emulsion polymerization aggregation method, polymer primary particles of a binder resin monomer obtained by the emulsion polymerization step, a colorant dispersion, a wax dispersion, etc. are prepared, and these are put in an aqueous medium. By dispersing and heating, it undergoes an agglomeration step and an aging step. 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 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. Particularly preferably, it is 1 part by mass or more. Further, it is usually 10 parts by mass or less, preferably 5 parts by mass 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 higher fatty acid ester waxes include behenyl behenate, stearyl stearate, stearates of pentaerythritol, montanic acid glycerides, etc., and fatty acids having 15 to 30 carbon atoms and 1 to 5 valent alcohols. Esters are preferred. Moreover, as an alcohol component which comprises ester, a C10-30 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. Or more. 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 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 the state of being dispersed in water in the presence of an emulsifier, and the volume average particle diameter of the colorant particles is usually 0.01 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, the charge control agent is dispersed in water using a surfactant, and the volume average particle diameter is 0.01 μm.
As described above, it is preferable to add a dispersion liquid of 3 μm or less to the aggregation step.

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. . 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. desirable. 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 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. 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.
<External addition process>
The toner of the present invention can be obtained through a multistage process in which the process of adding the external additive is performed in a plurality of stages. The number of steps in the process is not particularly limited as long as it is a plurality of steps, but is usually 2 steps or more, and usually 10 steps or less. From the viewpoint of manufacturability, it is preferably 3 steps or more, and preferably 5 steps or less.

The toner of the present invention can be obtained by externally adding at least silica particles to the surface of the toner base particles. However, the “others” other than the silica particles known as external additives may be used as long as the effects of the present invention are not impaired. May be used together and added to the toner base particles to adhere to or adhere to the surface of the toner base particles.
In addition, before the first stage external addition and after the final stage external addition, as long as the effects of the invention of the present application are not impaired, charging, flowability, cleaning properties, etc. Processing may be performed.

  Examples of the “other particles” include titanium oxide, aluminum oxide (alumina), zinc oxide, tin oxide, barium titanate, strontium titanate, hydrotalcite and the like as inorganic particles, and organic particles such as stearin. Organic resin particles such as organic acid salt particles such as zinc acid 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 Etc.

The blending ratio of the silica particles of the present invention to “other particles” is not particularly limited, and the amount of all external additives composed of the silica particles and “other particles” is not particularly limited, but the toner base particles 100 The amount of all external additives used is usually 2.2 parts by mass or more, preferably 2.4 parts by mass or more, and more preferably 2.6 parts by mass or more with respect to parts by mass. On the other hand, it is usually 6.0 parts by mass or less, preferably 5.0 parts by mass or less, and more preferably 4.0 parts by mass or less. If the amount used is too small, the fluidity may be deteriorated or the charge amount may not be controlled. On the other hand, if the amount used is too large, the free additive that has not adhered can contaminate the components in the cartridge. However, this may cause image defects.

Regarding the “other particles” other than the silica particles used in the present invention, the order of adhering or fixing to the surface of the toner base particles is not particularly limited, but may be used in combination with the silica base particles or not. It may be added separately.
In the present invention, the method for adhering or fixing the silica particles and “other particles” to the surface of the toner base particles is not particularly limited, and a mixer generally used for toner production can be used. 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.

  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”.

<Measurement method of average particle diameter of polymer primary particles>
Nikkiso Co., Ltd., Model: Microtrac Nanotrac 150 (hereinafter abbreviated as “Nanotrack”), according to the instruction manual of NanoTrack, using its analysis software Microtrac Particle Analyzer Ver10.1.2.-019EE Using ion-exchanged water having a degree of 0.5 μS / cm as a dispersion medium, the measurement was performed by the method described in the instruction manual under the following conditions or by inputting the following conditions.
Solvent refractive index: 1.333
・ Measurement time: 100 seconds
・ Number of measurements: 1 time
-Particle refractive index: 1.59
・ Transparency: Transmission
・ Shape: 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 circularity>
In the present invention, the “average circularity” is determined by dispersing toner base particles in a dispersion medium (Isoton II, manufactured by Beckman Coulter, Inc.) so as to be in the range of 5720 to 7140 particles / μL. The measurement is performed under the following apparatus conditions using a company (former Toa Medical Electronics Co., Ltd., FPIA 3000), and 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 detected HPFs: 2000 to 2500 The following are measured by the above apparatus and automatically calculated and displayed in the above apparatus, but "circularity" is defined by the following equation.

[Circularity] = [Perimeter of a circle with the same area as the projected particle area] / [Perimeter of projected particle image]
And 2000-2500 which is the number of HPF detection is measured, and the arithmetic average (arithmetic mean) of the circularity of each individual particle is displayed on the apparatus as “average circularity”.

<Method for measuring average primary particle size of silica particles>
In the present invention, the average primary particle size of the silica particles is determined by measuring the particle size of 2500 random particles from the silica fine particles and the inorganic particle sample on the transmission electron microscope image, and obtaining the average primary particle size by the number average. It was.

<Method for measuring average primary particle diameter of titanium oxide>
In the present invention, the average primary particle diameter of titanium oxide is a sphere equivalent diameter obtained from a measured BET specific surface area.

<Measuring method of average primary particle size of hydrotalcite>
The average primary particle size of hydrotalcite was measured by performing image analysis of SEM photographs. Specifically, the measurement was carried out by the following method. Using a scanning electron microscope S4500 manufactured by Hitachi, Ltd., after taking an appropriate number of photographs of the particles magnified 30000 times, 100 particles were randomly selected, and image analysis software WinROOF manufactured by Mitani Corporation These equivalent circle diameters were measured and the average value was defined as the average primary particle diameter.

<Measurement method of electrical resistance value>
For the measurement of the electrical resistance value in the present invention, an apparatus capable of measuring the resistivity of the powder under pressure is used. In this example, a powder resistance measurement system-PD51 type manufactured by Mitsubishi Chemical Corporation was used, and measurement was performed with a sample filling amount of 2.0 g and a weight of 4 kN.

<Measurement method of charge amount>
In the present invention, the charge amount of the inorganic particles is measured under the following conditions.
Carrier at temperature 23 ° C and humidity 55%: F-150 core (Powdertech) 19.8g
Inorganic particles: 0.2g
Is placed in a 20 ml glass bottle and left for 12 hours or longer. Thereafter, the mixture is mixed 50 times by hand shaking and stirred for 1 minute at an amplitude of 1.0 cm and a shaking speed of 500 rpm.

0.2 g is taken out from the glass bottle and measured with the blow-off TB-200 apparatus manufactured by Toshiba Chemical under the following settings.
N2 pressure gauge: 1.0Kg / cm ²
SET TIME: 20.0sec
Wire mesh set on Faraday gauge (Stainless steel: 400 mesh)
The charge amount Q / M (μC / g) per unit mass can be obtained by calculating the read value Q (μC) by the following formula.
Q / M (μC / g) = − (Q (μC) / (measured mass (g)) × 100

[Production of toner mother particle A]
<Preparation of wax dispersion>
30 parts of pentaerythritol tetrastearyl ester (H476 manufactured by NOF Corporation), 20% sodium dodecylbenzenesulfonate aqueous solution (Daiichi Kogyo Seiyaku Co., Ltd., Neogen S20A) (hereinafter abbreviated as “20% DBS aqueous solution”) 2.8 And 67.2 parts of demineralized water were heated to 90 ° C. and stirred for 10 minutes using a homomixer (Mark II f model, manufactured by Tokushu Kika Kogyo Co., Ltd.).

  Next, this dispersion was heated to 90 ° C., and circulation emulsification was started under a pressure condition of 25 MPa using a homogenizer (manufactured by Gorin Co., Ltd., 15-M-8PA type). A wax dispersion was prepared by dispersing until the average diameter (Mv) reached 250 nm.

<Preparation of polymer primary particle dispersion>
A reactor equipped with a stirrer (three blades), a heating / cooling device, a concentrating device, and a raw material / auxiliary charging device was charged with 42.9 parts of the above wax dispersion and 336 parts of demineralized water, and a nitrogen stream The temperature was raised to 70 ° C., and 3.2 parts of an 8% aqueous hydrogen peroxide solution and 3.2 parts of an 8% L (+)-ascorbic acid aqueous solution were added all at once with stirring.

  After 5 minutes, the following mixture of monomers and emulsifier aqueous solution and the following initiator aqueous solution were added over 4.5 hours, and after the dropwise addition of the mixture of monomers and emulsifier aqueous solution, the temperature was raised to 90 ° C. over 30 minutes. Warm up. Furthermore, the following additional initiator aqueous solution was added over 3 hours, and the internal temperature was maintained at 90 ° C. for 1 hour with further stirring.

[Monomers]
Styrene 76.8 parts
Butyl acrylate 23.2 parts Acrylic acid 1.5 parts Trichlorobromomethane 0.5 part Hexanediol diacrylate 1.0 part

[Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part Demineralized water 67.3 parts [Initiator aqueous solution]
8% aqueous hydrogen peroxide solution 12.4 parts 8% L (+)-ascorbic acid aqueous solution 12.4 parts

[Additive initiator aqueous solution]
8% aqueous hydrogen peroxide solution 9.3 parts 8% L (+)-ascorbic acid aqueous solution 9.3 parts After the completion of the polymerization reaction, the mixture was cooled to obtain a milky white primary polymer particle dispersion. The volume average diameter (Mv) of the polymer primary particles was 200 nm.

<Preparation of resin particle dispersion>
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 2.0 parts of a 20% DBS aqueous solution and 317 parts of demineralized water under a nitrogen stream. The temperature was raised to 90 ° C., and 3.2 parts of an 8% aqueous hydrogen peroxide solution and 3.2 parts of an 8% L (+)-ascorbic acid aqueous solution were added all at once while stirring.

After 5 minutes, polymerization of a mixture of the following monomers and an aqueous emulsifier was initiated (from the time when 3.2 parts of an 8% aqueous hydrogen peroxide solution and 3.2 parts of an 8% L (+)-ascorbic acid aqueous solution were added all at once. After 5 minutes), the following initiator aqueous solution was added over 6 hours from the start of polymerization, and further maintained at 90 ° C. for 1 hour with stirring.
[Monomers]
Styrene 88.0 parts
Butyl acrylate 12.0 parts Acrylic acid 1.5 parts Trichlorobromomethane 0.5 parts Hexanediol diacrylate 0.4 parts

[Emulsifier aqueous solution]
20% DBS aqueous solution 1.5 parts Demineralized water 66.4 parts [Initiator aqueous solution]
8% hydrogen peroxide aqueous solution 18.9 parts 8% L (+)-ascorbic acid aqueous solution 18.9 parts After completion of the polymerization reaction, the mixture was cooled to obtain a milky white resin particle dispersion. The volume average diameter (Mv) of the resin particles was 115 nm.

<Preparation of colorant dispersion>
In a container equipped with a stirrer (propeller blade), carbon black (Mitsubishi Chemical Corporation, Mitsubishi Carbon Black MA100S) 20 parts, 20% DBS aqueous solution 1 part, nonionic surfactant (Kao Corporation, Emulgen 120) 4 parts, 75 parts of ion-exchanged water having an electric conductivity of 2 μS / cm was added and predispersed to obtain a premix solution. The volume average diameter (Mv) of carbon black in the premix solution was 90 μm.

The premix solution was supplied to a wet bead mill and subjected to one-pass dispersion. The inner diameter of the stator was φ75 mm, the separator diameter was φ60 mm, the distance between the separator and the disk was 15 mm, and zirconia beads having a diameter of 100 μm (true density of 6.0 g / cm ³ ) were used as a dispersion medium.
The black colorant dispersion A is obtained by continuously supplying the premix slurry from a supply port at a supply speed of 50 L / hr by a non-pulsating metering pump and continuously discharging from the discharge port while keeping the rotation speed of the rotor constant. Got. The volume average diameter (Mv) of the colorant in the colorant dispersion was 150 nm.

<Manufacture of toner base particles>
Polymer primary particle dispersion Solid part 95 parts Resin particle dispersion Solid part 5 parts Colorant dispersion Colorant solid part 6 parts 20% DBS aqueous solution Solid part 0.1 part Using the above components, Toner mother particles were produced by the following procedure.

The polymer primary particle dispersion and 20% DBS aqueous solution were charged into a mixer equipped with a stirrer (double helical blade), heating / cooling device, concentrating device, and raw material / auxiliary charging device, and the internal temperature was 12 ° C. Mix evenly for 5 minutes. Subsequently, 0.52 parts of FeSO ₄ .7H ₂ O as a 5% aqueous solution of ferrous sulfate was added over 5 minutes at an internal temperature of 12 ° C. while continuing stirring, and then the colorant dispersion was added over 5 minutes. The mixture was uniformly mixed with the internal temperature kept at 12 ° C., and a 0.5% aluminum sulfate aqueous solution was added dropwise under the same conditions.

  Thereafter, the temperature was raised to 50 ° C. over 30 minutes with stirring, and then raised to 51.5 ° C. over 90 minutes. Here, when the volume median diameter was measured using a multisizer, it was 7.2 μm. Thereafter, while stirring, the resin particle dispersion is added over 7 minutes and held for 60 minutes, 20% DBS aqueous solution is added over 10 minutes and then heated to 70 ° C. over 20 minutes. The temperature was raised to 90 ° C. over a period of minutes. Then, it heated up to 96 degreeC over 30 minutes.

  Then, the slurry obtained by cooling to 30 degreeC over 20 minutes was extracted, and it suction-filtered with the aspirator using the filter paper of 5 types C (Toyo Filter Paper Co., Ltd. No5C). The cake remaining on the filter paper is transferred to a stainless steel container equipped with a stirrer (propeller blade), added with 8 kg of ion exchange water having an electric conductivity of 1 μS / cm, and uniformly dispersed by stirring at 50 rpm, and then stirred for 30 minutes. I left it.

  After that, suction filtration is again performed with aspirator using filter paper of type 5 C (manufactured by Toyo Roshi Kaisha Co., Ltd., No. 5C), and the solid matter remaining on the filter paper is again equipped with a stirrer (propeller blade) and has electrical conductivity. The sample was transferred to a 10 L container with 8 kg of 1 μS / cm ion exchange water, and uniformly dispersed by stirring at 50 rpm, and stirring was continued for 30 minutes. When this process was repeated 5 times, the electrical conductivity of the filtrate was 2 μS / cm.

The cake obtained here was spread on a stainless 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 mother particles A. The resulting toner base particle A had a volume median diameter of 7.0 μm and an average circularity of 0.960.
In Examples and Comparative Examples, the following silica particles A to C were used.
Silica particle A: The raw material is prepared by a dry method, and the surface is treated with polydimethylsiloxane.
(Average primary particle size 40 nm, BET: 20.09 m ² / g, charge amount: −131.9 μC / g)
Silica particle B: The raw material is prepared by a dry method, and the surface is treated with polydimethylsiloxane. (Average primary particle size 12 nm, BET: 108.5 m ² / g, charge amount: −504.6 μC / g)
Silica particle C: The raw material is prepared by a dry method, and the surface is treated with polydimethylsiloxane. (Average primary particle size 7 nm, BET: 123.6 m ² / g, charge amount: −330.9 μC / g)

[Example 1]
<Manufacture of toner A>
0.2 parts of the silica particles A were added to the base particles A (100 parts), and mixed and stirred for 2 minutes (first stage).
Subsequently, 0.1 part of silica particles B, hydrotalcite (average primary particle diameter: 0.4 μm, BET: 9.31 m ² / g, charge amount: 38.4 μC / g, electric resistance value: 3.01E + 11Ω · cm, 0.05)
Titanium oxide A (average primary particle size: 0.015 μm, BET: 97.28 m ² / g, charge amount: −33
. (3 μC / g, electrical resistance: 4.01E + 08Ω · cm)
Titanium oxide B (average primary particle size: 0.25 μm, BET: 15.55 m ² / g, charge amount: 21.8
μC / g, electric resistance: 1.69E + 08Ω · cm)
And stirred and mixed at 3000 rpm for 10 minutes (intermediate stage).
Further, 1.5 parts of silica particles B were added, and the mixture was further stirred and mixed at 3000 rpm for 10 minutes, followed by sieving to obtain toner A (final stage).

[Example 2]
<Manufacture of toner B>
In Example 1, Toner B was obtained in the same manner as in Example 1 except that 1.3 parts of the addition amount of silica particles B added to the final stage was used.
Example 3
<Manufacture of toner C>
In Example 1, Toner C was obtained in the same manner as in Example 1 except that 1.7 parts of the silica particles B added to the final stage was used.

Example 4
<Manufacture of toner D>
In Example 1, Toner D was obtained in the same manner as in Example 1 except that 1.9 parts of silica particles B added to the final stage was used.
[Comparative Example 1]
<Manufacture of toner E>
In Example 1, the addition amount of silica particles B added to the intermediate stage of the external addition step was 1.4 parts, hydrotalcite and titanium oxide B added to the intermediate stage were added to the final stage, and silica was added to the final stage. A toner E was obtained in the same manner as in Example 1 except that the particles B were not added.

[Comparative Example 2]
<Manufacture of toner F>
In Example 1, 0.1 part of silica particles B was added instead of silica particles A,
Toner F was obtained in the same manner as in Example 1 except that 1.4 parts of the addition amount of silica particles B added to the final stage was used.

[Comparative Example 3]
<Manufacture of toner G>
In Example 1, a toner G was obtained in the same manner as in Example 1 except that the silica particles C were used instead of the silica particles B.
The details of the external additive formulations of Examples and Comparative Examples are shown in Table 1.

<Evaluation method>
The obtained toner was evaluated for image quality by a live-action test.
For live-action, non-magnetic single component, organic photoreceptor (OPC) is used, roller charging, rubber development roller contact development method, process speed 119.7mm / second, tandem method, direct transfer method, thermal fixing method, blade drum cleaning A full color printer was used.
With this printer, after printing 8000 sheets of 5% printing rate chart continuously in an environment of temperature 10 ° C and humidity 20%,
The following items were judged.
a Image presence / absence due to contamination of charging roller on organic photoconductor drum
b. Cover on printed matter
c. Presence / absence of vertical stripes in the printing direction due to toner fusion to the charging blade Table 2 shows the evaluation results.

<Presence or absence of image defects due to charging roller contamination>
The presence or absence of image defects due to contamination of the charging roller was judged visually.
Judgment criteria are as follows.
○: No image defect
○ △: Minor image defects are observed, but there is no problem in actual use. ×: Obvious image defects are recognized, causing problems in actual use.

<Cover on printed matter>
The fog on the printed matter was evaluated as follows. That is, standard paper before and after printing (lightness 92, paper thickness 20lb, size letter)
The whiteness difference △ of Nippon Denshoku SE-6000 (standard light / viewing angle): C / 2, UV cut filt
er (with 420 nm)) was calculated. The paper cover was an average of three sheets.

Δ = delta Wb
Judgment criteria are as follows.
◎: Paper fog less than 0.7 ○: Paper fog 0.7 or more, less than 1.4 ×: Paper fog 1.4 or more <Presence / absence of vertical streak in the printing direction due to toner fusion to the charging blade>
Toner scattering around the developing tank unit was judged by visual evaluation of the toner scattering level around the developing tank unit and presence / absence of printed matter stains. Judgment criteria are as follows.

○: There is almost no toner fusion to the charging blade visually, and the printed matter has no vertical stripes. ○ △: Toner fusion to the charging blade visually and vertical stripes to the printed matter are somewhat recognized. No problem in use ×: Severe toner fusion to the charging blade visually and vertical streaks on the printed matter were observed, causing trouble in actual use

Claims (4)

A toner obtained through a step of adding an external additive to toner base particles containing a binder resin, a pigment and a wax, and satisfying the following (A) to (D), for electrostatic image development toner.
(A) ΔBET (m ² / g), which is the difference between BET (m ² / g) of the toner base particles and BET (m ² / g) of the toner, is 1.00 or more and 2.00 or less ( B) The process of adding the external additive is a multi-stage process (C) The external additive contains silica (D) Silica particles contained in the external additive added in the first stage of the addition process Mn ₁ -Mn _f which is the difference between the average primary particle size Mn ₁ (nm) of the silica and the average primary particle size Mn _f (nm) of the silica particles added to the final stage is greater than 0 nm and 30 nm or less.   The step of adding the external additive is a multi-step process, and the amount of the external additive added in the final step of the step of adding the external additive is 60% by mass or more based on the total amount of the external additive. The toner for developing an electrostatic charge image according to claim 1, wherein the toner is 1% by mass or less. The static additive according to claim 1 or 2, wherein the external additive burying rate (%) represented by the following formula after the final stage of the step of adding the external additive is 20% or more and 55% or less. Toner for charge image development.
(External additive burying rate) = ((I) Total specific surface area of external additives embedded in base particles) × 100
/ ((II) total specific surface area of added external additives)
(I) = {(a1 + b1) / (a2 + b2) −c} × 100
(II) = (a1 + b1) / (a2 + b2) -d
[In the above formula,
a1 represents the surface area (m ² ) of the toner base particles,
a2 represents the input amount (g) of toner base particles,
b1 represents the total surface area (m ² ) of the external additives introduced up to the final stage,
b2 represents the input amount (g) of the external additive to be added up to the final stage,
c is the measured BET value of the toner after the final stage (m ² / g)
d represents the BET value (m ² / g) of the toner base particles after the final stage.
d is a value calculated by dividing the measured BET value (m ² / g) of the toner base particles by the sum of the input amount (g) of the external additive and base particles to be introduced up to the final stage. ]   4. The electrostatic image developing toner according to claim 3, wherein in the step of adding the external additive, the silica particles used in the first stage are silica particles of 35 nm or more and 150 nm or less. 5.