JP2007248953A - Toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner which is excellent in cleaning performance and can form a stable image even upon endurance in respect to the emulsion aggregation toner. <P>SOLUTION: The toner is an aggregation method toner having weight average particle size (D4) of 4 to 8 μm, average roundness of 0.975 to 0.995 and peak molecular weight (Mp) of binder resin of 5,000 to 60,000, and comprises at least toner particles, silica fine particles subjected to hydrophobic treatment and inorganic fine particles, wherein, when a measured value in a toner dispersion liquid A is made to be C1 and the measured value in a toner dispersion liquid B is made to be C2 in the measurement of the number of particles in the range of 0.6 to 2.0 μm according to a flow type particle image analyzer, the value C of (C1/C2)×100 is 130 to 200 and, in the toner dispersion liquid B, the roundness standard deviation in particle size referred to the number measured by the flow type particle image analyzer is 0.025 to 0.040 and the roundness standard deviation of a particle group of 50% particle size or more measured in the same conditions is less than 0.025. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a toner used in a recording method using an electrophotographic method, an electrostatic recording method, an electrostatic printing method, or the like.

  Conventionally, many methods are known as electrophotographic methods. Generally, a charging process for charging an image carrier using a photoconductive substance and an electrostatic latent image are formed on the charged image carrier. A developing process for developing the electrostatic latent image formed on the image carrier, a transferring process for transferring the developed image to a transfer material by a transfer means, and a transfer process on the transfer material. The target copy is obtained through a fixing step of heating and fixing the transferred image.

  In recent years, devices using electrophotography have been applied to multifunction devices such as printers and fax machines and scanners in addition to conventional copying machines. Further, with the popularization of digital cameras and the enhancement of image quality, full-color images with higher image quality have been demanded.

  Therefore, as a method for producing toner, an emulsion aggregation method has been proposed as means for enabling intentional control of toner shape and toner surface structure (see Patent Document 1 and Patent Document 2). In this toner production method, a resin fine particle dispersion generally prepared by emulsion polymerization or the like and a colorant particle dispersion in which a colorant is dispersed in a solvent are mixed at least to form an aggregate corresponding to the toner particle size. This is a production method for obtaining a toner through a step of fusing the aggregate by heating. This toner manufacturing method not only facilitates the reduction of the toner particle size, but also makes it possible to obtain a toner having an excellent particle size distribution.

  Furthermore, in recent years, in order to realize a high-definition image, the spherical shape of the emulsion aggregation method toner is remarkable. However, even if the toner is simply spheroidized, cleaning failure occurs. In view of this, a method has been proposed in which the charge amount of the toner is appropriately controlled to prevent deterioration of the cleaning property due to excessive charging of the toner (see Patent Document 3). However, as a result of investigations by the present inventors, the toner produced by this method was printed out in a continuous mode at a high printing ratio in a high temperature and high humidity environment (35 ° C./90% RH). The cleaning was bad. From this, it was found that there is still room for improvement in the cleaning properties of the toner in a high temperature and high humidity environment.

Japanese Patent Laid-Open No. 63-282275 JP-A-6-250439 JP 2002-372806 A

An object of the present invention is to provide a toner that solves the above problems.
That is, an object of the present invention is to provide an emulsion aggregation method toner that is excellent in cleaning properties and durability and achieves high image quality.

  As a result of extensive studies by the present inventors, attention is paid to the average circularity, peak molecular weight (Mp), and the presence state of fine particles on the toner particle surface, and these are set to a specific range to prevent defective cleaning. The inventors have found that a good image can be formed and completed the present invention.

That is, the present invention relates to an emulsion aggregation method toner obtained through a step of aggregating at least polymer fine particles and colorant fine particles to form a fine particle aggregate and a ripening step of causing fusion between the fine particles in the fine particle aggregate. ,
The weight average particle diameter (D4) is 4 to 8 μm, the average circularity is 0.975 to 0.995, the peak molecular weight (Mp) of the binder resin is 5000 to 60000,
The toner contains at least toner particles, hydrophobized silica fine particles and inorganic fine particles,
In the measurement of the number of particles of 0.6 to 2.0 μm using a flow type particle image analyzer, the measured value of the toner dispersion A ultrasonically dispersed for 5 minutes is C1, and the toner dispersion B is ultrasonically dispersed for 1 minute. When the measured value at is C2, the value C of (C1 / C2) × 100 is 130 to 200,
In Toner Dispersion B, the circularity standard deviation of the number-based particle diameter measured by a flow particle image analyzer is 0.025 to 0.040, and the circularity standard deviation of a particle group having a particle diameter of 50% or more is 50% or more. The present invention relates to a toner characterized in that is less than 0.025.

  The toner of the present invention is excellent in cleaning properties and can form a stable image even during durability.

  The toner of the present invention is an emulsion aggregation toner obtained through a step of aggregating at least polymer fine particles and colorant fine particles to form a fine particle aggregate and a ripening step of causing fusion between the fine particles in the fine particle aggregate. The weight average particle diameter (D4) is 4 to 8 μm, the average circularity is 0.975 to 0.995, the peak molecular weight (Mp) of the binder resin is 5000 to 60000, and the toner is a toner. In the measurement of the number of particles having a particle size of 0.6 to 2.0 μm using a flow type particle image analyzer, the measured value in the toner dispersion A is C1, and the toner contains at least particles, hydrophobized silica particles and inorganic particles. When the measured value in the dispersion B is C2, the value C of (C1 / C2) × 100 is 130 to 200. In the toner dispersion B, the value is measured with a flow type particle image analyzer. Toner satisfying the relationship that the circularity standard deviation in the number-based particle size is 0.025 to 0.040 and the circularity standard deviation of the particle group having a particle size of 50% or more is less than 0.025. It becomes possible to suppress poor cleaning while achieving high image quality by making the spheroid.

  As a result of intensive studies, the present inventors have formed a high-definition and high-definition image by using a spherical toner, and by controlling the presence of external additives and fine particles on the toner particle surface. It was found that poor cleaning can be prevented.

  Although these reasons are not necessarily clear, an external additive that is liberated from the toner particles by setting the conditions of the ripening step and the external addition step to an appropriate range, and further setting the peak molecular weight (Mp) of the toner to an appropriate range. The amount of fine particles can be controlled, and the free external additive and fine particles play the role of a cleaning auxiliary agent, so that the cleaning failure can be prevented.

  The features of the present invention will be described below.

  The toner of the present invention has a weight average particle diameter (D4) of 4 to 8 μm. When the toner is less than 4 μm, the fluidity and agitation as a powder are lowered, and it becomes difficult to uniformly charge individual toner particles. This is not preferable for the toner used in the present invention. When the weight average particle diameter of the toner exceeds 8 μm, characters and line images are likely to be scattered, and the reproduction of one dot tends to deteriorate, and high resolution is difficult to obtain.

  The toner of the present invention satisfies the following conditions in an analysis method using a flow type particle image analyzer (hereinafter referred to as “FPIA method”).

When 15 to 20 mg of toner is dispersed in 10 ml of water in which 0.1 mg of a nonionic surfactant is dissolved to prepare a dispersion, and the dispersion is irradiated with ultrasonic waves of 20 kHz and 50 W / 10 cm ³ for 5 minutes (toner When the measured value of the particle having a particle size of 0.6 to 2.0 μm by the flow type particle image analyzer of Dispersion A) is C1, and the dispersion is irradiated with ultrasonic waves for 1 minute (toner dispersion) The value C of (C1 / C2) × 100 is 130 to 200, where C2 is a measured value of particles having a particle diameter of 0.6 to 2.0 μm by the flow type particle image analyzer of Liquid B).

When the dispersion is irradiated with ultrasonic waves of 20 kHz and 50 W / 10 cm ³ for 1 minute, the external additive externally added to the toner particle surface and the fine particles adhering weakly to the toner particle surface are released from the toner particle and measured. Counted as value C2.

When the dispersion is further irradiated with ultrasonic waves of 20 kHz and 50 W / 10 cm ³ , the fine particles adhering to the surface of the toner particles are released from the toner particles when the irradiation time is 1 minute. The measured value C1 at the time of the ultrasonic irradiation time of 5 minutes is counted by adding fine particles released from the toner particles after the irradiation time of 1 minute. As a result, the value C of (C1 / C2) × 100 indicates the increase rate of the measured value C1 with respect to the measured value C2.

  When the value C of (C1 / C2) × 100 is in the range of 130 to 200, the external additive and fine particles that are moderately released from the toner particles serve as a cleaning aid, and the cleaning properties are improved. When the value C is less than 130, the amount of free external additive and fine particles is reduced, and the cleaning property is deteriorated. When the value C exceeds 200, external additives and fine particles released from the toner surface excessively increase due to the durability of a large number of sheets, and triboelectric chargeability, image unevenness, and transferability are liable to occur. The value C is more preferably 135 to 180.

  The average circularity of a particle group having an equivalent circle diameter of 0.60 μm or more in the number-based particle diameter measured by the flow particle image analyzer of the toner of the present invention is 0.975 to 0.995. To do. A toner having an average circularity of 0.975 or more has few edge portions on the toner surface, so that the localization of electric charge within one particle hardly occurs, and the charge amount distribution tends to be sharp, so that the latent image On the other hand, it is developed faithfully. On the other hand, toner having an average circularity exceeding 0.995 is not preferable because the circularity is very high and there is a concern about poor cleaning.

  Further, when the circularity standard deviation of the circularity frequency distribution of the toner is 0.025 to 0.040, it is possible to make the toner cleaning property and charge amount appropriate. When the circularity standard deviation is larger than 0.040, the charge distribution of the toner tends to be widened, which may cause fogging. When the circularity standard deviation is smaller than 0.025, there is no variation in the circularity and the cleaning property is poor. However, since a particle group having a particle size of 50% or more in the number-based particle size is advantageous for cleaning, the circularity standard deviation of 50% or more of particle size is 0 in order to sharpen the charge distribution and suppress fogging. Must be less than 0.025.

  The toner of the present invention is characterized in that the binder resin has a peak molecular weight (Mp) of 5000 to 60000 as measured by GPC. When the peak molecular weight is less than 5000, the toner becomes brittle and fog is likely to occur. When the peak molecular weight is larger than 60,000, the melt viscosity becomes too high, which may cause a problem in fixability. A more preferable peak molecular weight is 10,000 to 30,000.

  The toner of the present invention preferably has a shape factor SF-1 of 100 to 120. When the shape factor SF-1 exceeds 120, the toner is easily damaged by the durability stress, and the transferability is also deteriorated.

  A specific method for measuring the physical properties of the toner in the present invention will be described below.

  As an apparatus for measuring the weight average particle diameter of the toner in the present invention, for example, a Coulter Counter TA-II type or Coulter Multisizer (manufactured by Coulter Co.) is used. Measurements can be made with a measuring device connected to a personal computer. In this measurement, an electrolytic solution is used. As this electrolytic solution, for example, a 1% NaCl aqueous solution prepared using primary sodium chloride or ISOTON R-II (manufactured by Coulter Scientific Japan) can be used.

  As a measurement method, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes. Using a 100 μm aperture as the aperture, the volume and number of toners of 2 μm or more are measured by the Coulter Counter TA-II type. The volume distribution and the number distribution are calculated. Then, a volume-based weight average particle diameter (D4: the median value of each channel is a representative value of the channel) obtained from the volume distribution according to the present invention was obtained.

  C1 and C2 of the toner of the present invention are performed by the following method using a flow particle image analyzer (Flow Particle Image Analyzer).

  The toner is measured using a flow type particle image analyzer FPIA-1000 manufactured by Toa Medical Electronics Co., Ltd.

The measurement is performed by removing fine dust through a filter, and as a result, in 10 ^-3 cm ³ of water having a measurement range (for example, an equivalent circle diameter of 0.60 μm or more and less than 159.21 μm) in 10 ml of water having 20 or less particles. Add a few drops of nonionic surfactant (preferably Contaminone N manufactured by Wako Pure Chemical Industries, Ltd.), further add 15-20 mg of measurement sample, and 20 kHz, 50 W / 10 cm ³ with UH-50 manufactured by Ultrasonic Disperser STM. Dispersion treatment is performed for 1 minute under the conditions, and further dispersion treatment is performed for a total of 5 minutes, and the sample concentration is 9000 to 11,000 particles / 10 ⁻³ cm ³ (for particles in the measurement equivalent circle diameter range). Using the liquid, the particle size distribution of particles having an equivalent circle diameter of 0.60 μm or more and less than 159.21 μm is measured.

  The outline of the measurement is described in the catalog (June 1995 edition) of FPIA-1000 published by Toa Medical Electronics Co., Ltd., the operation manual of the measuring apparatus, and JP-A-8-136439. It is.

  The sample dispersion liquid is passed through a flow path (expanded along the flow direction) of a flat and flat transparent flow cell (thickness: about 200 μm). In order to form an optical path that passes across the thickness of the flow cell, the strobe and the CCD camera are mounted on the flow cell so as to be opposite to each other. While the sample dispersion is flowing, strobe light is irradiated at 1/30 second intervals to obtain an image of the particles flowing through the flow cell, so that each particle has a certain range parallel to the flow cell. Photographed as a two-dimensional image. From the area of the two-dimensional image of each particle, the diameter of a circle having the same area is calculated as the equivalent circle diameter.

  In about 1 minute, the equivalent circle diameter of 1200 or more particles can be measured, and the number based on the equivalent circle diameter distribution and the ratio (number%) of particles having a prescribed equivalent circle diameter can be measured. In actual measurement, particles are measured in the range where the equivalent circle diameter is 0.60 μm or more and less than 159.21 μm.

  The average circularity in the present invention is used as a simple method for quantitatively expressing the shape of the particles. In the present invention, the average circularity is measured using a flow type particle image analyzer “FPIA-1000” manufactured by Toa Medical Electronics. The degree of circularity of each particle measured for a particle group having an equivalent circle diameter of 0.60 μm or more and less than 159.21 μm was determined by the following equation (1), and further measured by the following equation (2). The sum of the circularity of the particles is defined as (ai), and the value obtained by dividing by the total number of particles (m) is defined as the average circularity (a).

Measuring means are as follows. A few drops of nonionic surfactant (preferably Contaminone N manufactured by Wako Pure Chemical Industries, Ltd.) is added to 10 ml of water, and further 15 to 20 mg of a measurement sample is added, and 20 kHz, 50 W is obtained using an ultrasonic dispersing device STM UH-50. / 10 cm ³ for 1 minute, and the sample concentration is 9000 to 11000 particles / 10 ⁻³ cm ³ (for particles in the equivalent diameter range of the measurement circle). Measurement is performed to determine the average circularity of a particle group having a circle-equivalent diameter of 0.60 μm or more and less than 159.21 μm.

  The average circularity in the present invention is an index of the degree of unevenness of the developer, and is 1.000 when the developer is a perfect sphere, and the circularity becomes smaller as the surface shape becomes more complicated.

  The peak molecular weight (Mp) of the binder resin of the toner in the present invention is measured by GPC (gel permeation chromatography) under the following conditions.

  First, as a sample preparation, 1 g of toner and 200 ml of toluene were precisely weighed and subjected to reflux extraction for 12 hours using a Soxhlet extractor. After the predetermined time, the filtrate was concentrated under reduced pressure using a rotary evaporator to obtain a toluene usable component of toner. This toluene-usable component was dissolved in tetrahydrofuran (THF) at room temperature so as to be 0.4 to 0.6 mg / ml, and the obtained solution was filtered through a solvent-resistant membrane filter having a pore diameter of 0.2 μm.

<GPC measurement conditions for toluene-soluble component of resin component>
Apparatus: GPC-150C (manufactured by Waters)
Column: 7 series of KF801-7 (manufactured by Shodex) Temperature: 40 ° C
Solvent: THF
Flow rate: 1.0 ml / min.
Sample: 0.1 ml of a sample having a concentration of 0.4 to 0.6% by weight is measured under the above conditions, and a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample is used in calculating the molecular weight of the sample.

The shape factor SF-1 of the present invention was obtained by sampling 100 images of 500 times toner particles randomly using an FE-SEM (S-800) manufactured by Hitachi, Ltd., and the image information was made by Nireco through an interface. An analysis is performed by introducing the image analysis apparatus (Luxex 3), and an arithmetic average value of values obtained by the following expression is defined as SF-1 (sphericity of toner particles).
SF-1 = {(MXLNG) ² / AREA} × (π / 4) × 100
(MXLNG: absolute maximum length, AREA: toner projected area)

  Next, the toner of the present invention will be described in detail.

  The toner obtained by the present invention is a particulate material containing at least polymer fine particles and colorant fine particles, and if necessary, a release agent, a charge control agent, and other additives.

  The toner of the present invention is produced by an emulsion aggregation method. In the emulsion aggregation method, at least polymer fine particles and colorant fine particles obtained by emulsion polymerization and, if necessary, charge control agent particles are co-aggregated to form core aggregate particles, and further polymer fine particles are adhered or fixed. Thus, aggregated particles having a core / shell structure are formed, and a resin in the aggregated particles is fused to form toner particles. Thereafter, silica fine particles and inorganic fine particles are added to the toner particles to produce a toner.

(Emulsion polymerization process)
First, the emulsion polymerization process for producing the polymer fine particles used in the present invention will be described. In the emulsion polymerization step, the polymerization of the monomer proceeds in the emulsion by sequentially adding the monomer to the aqueous medium containing the emulsifier and the polymerization initiator, and the emulsion polymerization containing the polymer fine particles (binder resin). A latex is produced.

  Examples of the polymer include thermoplastic binder resins. Specifically, homopolymers or copolymers (styrene-based resins) of styrenes such as styrene, parachlorostyrene, and α-methylstyrene; Single weight of esters having vinyl group such as methyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate Polymer or copolymer (vinyl resin); homopolymer or copolymer of vinyl nitriles such as acrylonitrile and methacrylonitrile (vinyl resin); homopolymer of vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether Or copolymer (vinyl resin); vinyl methyl ketone, vinyl Homopolymers or copolymers of vinyl ketones such as isopropenyl ketone (vinyl resins); Homopolymers or copolymers of olefins such as ethylene, propylene, butadiene, and isoprene (olefin resins); epoxy resins and polyesters Examples thereof include non-vinyl condensation resins such as resins, polyurethane resins, polyamide resins, cellulose resins, and polyether resins, and graft polymers of these non-vinyl condensation resins and vinyl monomers. These resins may be used alone or in combination of two or more.

  Among these resins, vinyl resins are particularly preferable. In the case of a vinyl resin, it is advantageous in that a resin particle dispersion can be easily prepared by emulsion polymerization or seed polymerization using an ionic surfactant or the like. Examples of the vinyl monomer include acrylic acid, methacrylic acid, maleic acid, cinnamic acid, fumaric acid, vinyl sulfonic acid, ethylene imine, vinyl pyridine, vinyl amine, and other vinyl polymer acids and vinyl polymer bases. The monomer used as a raw material is mentioned. In the present invention, the resin particles preferably contain the vinyl monomer as a monomer component, and a styrene-acrylic resin with little change in charge amount of the toner in a high temperature and high humidity or low temperature and low humidity environment is preferable. In the present invention, among these vinyl monomers, vinyl polymer acids are more preferable from the viewpoint of ease of formation reaction of vinyl resins, and specifically, acrylic acid, methacrylic acid, maleic acid, cinnamon. A dissociable vinyl monomer having a carboxyl group such as an acid or fumaric acid as a dissociating group is particularly preferred from the viewpoint of controlling the degree of polymerization and the glass transition point. Furthermore, at this time, in order to adjust the molecular weight, a chain transfer agent, a crosslinking agent, or the like can be used in combination.

  For example, the chain transfer agent is not particularly limited, and for example, mercaptans such as octyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, halogen compounds such as carbon tetrabromide, disulfides and the like are used.

  Furthermore, as the crosslinking agent, those having two or more unsaturated bonds such as divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, hexanediol diacrylate, diallyl phthalate, etc. In particular, divinylbenzene is preferably used.

  In the present invention, the radical polymerization initiator can be appropriately used as long as it is water-soluble. For example, persulfates (potassium persulfate, ammonium persulfate, etc.), azo compounds [4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis (2-amidinopropane) salts, etc.], Examples thereof include peroxide compounds such as hydrogen oxide and benzoyl peroxide.

  Furthermore, the radical polymerization initiator can be combined with a reducing agent as necessary to form a redox initiator. By using a redox initiator, the polymerization activity is increased, the polymerization temperature can be lowered, and the polymerization time can be further shortened.

  The polymerization temperature may be any temperature as long as it is equal to or higher than the lowest radical generation temperature of the polymerization initiator, but a range of 50 ° C. to 80 ° C., for example, is used under normal pressure conditions. Further, polymerization can be performed at a temperature equal to or higher than the boiling point of the dispersion (usually an aqueous medium) under pressurized conditions.

  Surfactants that can be used for polymerization include sulfonates (sodium dodecylbenzenesulfonate, sodium arylalkylpolyethersulfonate, 3,3-disulfonediphenylurea-4,4-diazo-bis-amino-8- Sodium naphthol-6-sulfonate, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-6-sulfonate Sulfate ester salts (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.), fatty acid salts (sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate) , Potassium stearate, calcium oleate), and the like.

  The average particle size of the polymer fine particles is usually 1 μm or less, preferably 0.01 to 1 μm. When the average particle size exceeds 1 μm, the particle size distribution of the finally obtained toner is broadened or free particles are generated, which tends to cause a decrease in performance and reliability. On the other hand, when the average particle size is within the above range, there are no disadvantages, and the uneven distribution among the toners is reduced, the dispersion in the toners is improved, and the variation in performance and reliability is advantageous.

(Dispersion preparation process)
The polymer fine particle dispersion is prepared, for example, as follows. That is, the resin in the polymer fine particles is a homopolymer or copolymer of a vinyl monomer such as an ester having a vinyl group, the vinyl nitrile, the vinyl ether, or the vinyl ketone (vinyl resin). In this case, the vinyl monomer is produced by emulsion polymerization or seed polymerization in an ionic surfactant to produce a vinyl monomer homopolymer or copolymer (vinyl resin). A dispersion is prepared by dispersing resin particles in an ionic surfactant. When the resin in the polymer fine particles is a resin other than the homopolymer or copolymer of the vinyl monomer, the resin may be dissolved in an oily solvent having a relatively low solubility in water. For example, the resin is dissolved in the oily solvent, and this solution is finely dispersed in water together with an ionic surfactant and a polymer electrolyte using a disperser such as a homogenizer, and then heated or reduced in pressure to form the oily solvent. Is evaporated to prepare a dispersion liquid in which resin particles other than vinyl resin are dispersed in an ionic surfactant.

  The dispersion means is not particularly limited, and examples thereof include known dispersion apparatuses such as a rotary shear type homogenizer and a ball mill having a medium, a sand mill, and a dyno mill.

  The colorant fine particle dispersion is obtained by dispersing at least colorant fine particles in a dispersant. Examples of the colorant include phthalocyanine pigments, monoazo pigments, bisazo pigments, and quinacridone pigments. Specific examples thereof include, for example, carbon black, chrome yellow, hansa yellow, benzidine yellow, sren yellow, quinoline yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brillianthamine 3B, brillianthamine. 6B, DuPont Oil Red, Pyrazolone Red, Resol Red, Rhodamine B Lake, Lake Red C, Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Phthalocyanine Green, Malachite Green Oxalate, etc. Various pigments: acridine, xanthene, azo, benzoquinone, azine, anthraquinone, dioxane Various dyes such as gin, thiazine, azomethine, indico, thioindico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, thiazine, thiazole, xanthene, etc. . These colorants may be used alone or in combination of two or more.

  The average particle diameter of the colorant fine particles is preferably 0.5 μm or less, and more preferably 0.2 μm or less. When the average particle diameter exceeds 0.5 μm, irregular reflection of visible light cannot be prevented, and when coarse particles are present, coloring power, color reproducibility, and OHP permeability are adversely affected, and an aggregation process described later. In this case, the polymer fine particles and the colorant fine particles do not aggregate, or even if they aggregate, they may be detached at the time of fusion, which is not preferable in that the quality of the obtained toner may be deteriorated. On the other hand, when the average particle size is within the above range, there are no disadvantages, and the uneven distribution among the toners is reduced, the dispersion in the toner is good, and the variation in performance and reliability is advantageous. .

  The release agent fine particle dispersion is obtained by dispersing at least release agent fine particles in a dispersant.

  As the releasing agent, those having a melting point of 150 ° C. or lower are used, and those having a melting point of preferably 45 ° C. to 130 ° C. can satisfy both durability and release properties.

  For example, low molecular weight polyolefins such as polyethylene; silicones having a melting point (softening point) upon heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide; ester waxes such as stearyl stearate Plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil; animal waxes such as beeswax; montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, etc. And particles such as mineral / petroleum wax; and modified products thereof. Among these, ester wax is preferably used from the viewpoints of stability when it is used as a release agent particle dispersion, environmental resistance when it is made into a toner, image stability, and the like.

  As an optimal wax capable of achieving a good balance between low temperature fixability and durability by matching with the physical properties of the binder resin of the present invention, a low melting point ester wax having a melting point of 45 ° C. or higher and 70 ° C. or lower is preferable.

  In order to widen the latitude of the fixable temperature, a function can be suitably imparted by using a high melting point wax having a melting point higher than 70 ° C. and not higher than 130 ° C. in addition to the low melting point wax.

  The average particle size of the release agent fine particles is preferably 2.0 μm or less, and more preferably 1.0 μm or less. If the average particle size exceeds 2.0 μm, the toner content tends to be more likely to occur between the toners, which adversely affects the stability of the image over a long period of time. On the other hand, when the average particle size is within the above range, uneven distribution between toners is reduced, dispersion in the toner is improved, and variations in performance and reliability are reduced.

  The combination of the colorant fine particles, the polymer fine particles, and the release agent fine particles is not particularly limited and may be appropriately selected depending on the purpose.

  In addition to the polymer fine particle dispersion, the colorant fine particle dispersion, and the release agent fine particle dispersion, a particle dispersion obtained by dispersing appropriately selected particles in a dispersant may be further mixed.

  The particles contained in the particle dispersion are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include internal additive particles, charge control agent particles, inorganic particles, and abrasive particles. In the present invention, these particles may be dispersed in the polymer fine particle dispersion or the colorant fine particle dispersion.

  Examples of the charge control agent particles include particles such as quaternary ammonium salt compounds, nigrosine compounds, compounds composed of complexes of aluminum, iron, chromium, zinc, zirconium, and the like. The charge control agent particles in the present invention are preferably made of materials that are difficult to dissolve in water from the viewpoints of controlling ionic strength that affects the stability during aggregation and fusion and reusing wastewater.

  As an average particle diameter of each above-mentioned particle | grain, it is 1 micrometer or less normally, and it is preferable that it is 0.01-1 micrometer. When the average particle diameter exceeds 1 μm, the particle diameter distribution of the finally obtained toner is widened, and performance and reliability are likely to be lowered. On the other hand, when the average particle size is within the above range, there are no disadvantages, and the uneven distribution among the toners is reduced, the dispersion in the toners is improved, and the variation in performance and reliability is advantageous.

  Examples of the dispersant contained in the polymer fine particle dispersion, the colorant fine particle dispersion, the release agent fine dispersion, and the particle dispersion include an aqueous medium containing a polar surfactant. . Examples of the aqueous medium include water such as distilled water and ion exchange water, and alcohols. These may be used individually by 1 type and may use 2 or more types together. The content of the polar surfactant in the dispersant having the polarity cannot be generally defined and can be appropriately selected according to the purpose.

  Examples of the polar surfactant include anionic surfactants such as sulfate ester, sulfonate, phosphate, and soap; cationic surfactants such as amine salt type and quaternary ammonium salt type Is mentioned. Specific examples of the anionic surfactant include sodium dodecylbenzenesulfonate, sodium dodecylsulfate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate and the like. Specific examples of the cationic surfactant include alkylbenzene dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, distearyl ammonium chloride and the like. These may be used individually by 1 type and may use 2 or more types together.

  In the present invention, these polar surfactants and nonpolar surfactants can be used in combination. Examples of the nonpolar surfactant include nonionic surfactants such as polyethylene glycol, alkylphenol ethylene oxide adducts, and polyhydric alcohols.

  The content of the polymer fine particles in 100 parts by mass of the polymer fine particle dispersion is preferably 5 to 60 parts by mass. The content of the polymer fine particles in 100 parts by mass of the aggregated particle dispersion when the aggregated particles are formed is preferably 50 parts by mass or less.

  The content of the colorant fine particles is preferably about 1 to 10 parts by mass with respect to 100 parts by mass of the binder resin in the aggregated particle dispersion when the aggregated particles are formed.

  The content of the release agent fine particles is about 1 to 25 parts by mass and about 5 to 20 parts by mass with respect to 100 parts by mass of the binder resin in the aggregated particle dispersion when the aggregated particles are formed. Is preferred. When the content is less than 5 parts by mass, a sufficient release effect cannot be obtained and the low-temperature fixability is poor. On the other hand, if the content of the release agent exceeds 20 parts by mass, the amount of the existing surface of the release agent or the amount of precipitation increases with the endurance deterioration of the toner, so that the fog characteristics deteriorate. Moreover, when the said content is larger than 20 mass parts, a particle size distribution may spread depending on the kind of mold release agent, and a characteristic may deteriorate. In this case, for example, when the resin particles are produced, the above problem can be solved by performing seed polymerization on the release agent.

  Further, in order to control the chargeability of the obtained toner, the charge control particles and the polymer fine particles may be added after the aggregated particles are formed.

  The particle diameters of the colorant fine particle dispersion, the release agent fine dispersion, the particle dispersion and the like were measured using a laser diffraction / scattering particle size distribution measuring apparatus LA-920 manufactured by Horiba.

(Aggregation process)
In the first aggregating step for forming the core aggregated particles, aggregated particles are formed in the mixed solution to prepare an aggregated particle dispersion. The agglomerated particles can be formed in the mixed solution by adding, for example, a pH adjusting agent, a flocculant, and a stabilizer to the mixed solution and mixing them, and appropriately adding temperature, mechanical power and the like.

  Examples of the pH adjuster include alkalis such as ammonia and sodium hydroxide, and acids such as nitric acid and citric acid. Examples of the flocculant include monovalent metal salts such as sodium and potassium; divalent metal salts such as calcium and magnesium; trivalent metal salts such as iron and aluminum; and alcohols such as methanol, ethanol and propanol. It is done.

  Examples of the stabilizer mainly include the polar surfactant itself or an aqueous medium containing the same. For example, when the polar surfactant contained in the aqueous dispersion is anionic, a cationic one can be selected as the stabilizer.

  The addition / mixing of the flocculant and the like is preferably performed at a temperature below the glass transition point of the resin contained in the mixed solution. When the mixing is performed under this temperature condition, aggregation proceeds in a stable state. The mixing can be performed using, for example, a known mixing device, a homogenizer, a mixer and the like.

  In the second aggregating step, the second polymer fine particles are adhered to the surface of the core agglomerated particles obtained in the first aggregating step using a polymer fine particle dispersion containing the second polymer fine particles. By forming a coating layer (shell layer), aggregated particles having a core / shell structure in which a shell layer is formed on the surface of the core aggregated particles are obtained. The second polymer fine particles used at this time may be the same as or different from the first polymer fine particles.

  The first and second aggregating steps may be repeated in a plurality of steps.

(Aging process)
The aging step is a step of heating and fusing the core / shell aggregated particles. Before entering the ripening step, the pH adjuster, the polar surfactant, the nonpolar surfactant, and the like can be appropriately added in order to prevent fusion between toner particles.

  The heating temperature ranges from the glass transition temperature of the resin contained in the core / shell aggregated particles (when there are two or more types of resin, the glass transition temperature of the resin having the highest glass transition temperature) to the decomposition of the resin. Any temperature is acceptable. Therefore, the temperature of the heating differs depending on the type of resin of the polymer fine particles and cannot be generally defined, but generally the glass transition temperature of the resin contained in the aggregated particles or the adhered particles ~ 140 ° C. In addition, the said heating can be performed using a publicly known heating apparatus and instrument.

  As the fusing time, a short time is sufficient if the heating temperature is high, and a long time is necessary if the heating temperature is low. That is, the fusion time depends on the temperature of heating and cannot be defined unconditionally, but is generally 30 minutes to 10 hours.

  The toner particles obtained through the above steps can be solid-liquid separated according to a known method, the toner particles can be recovered, and then washed, dried, and the like under appropriate conditions.

(External addition process)
In the present invention, various fine powders generally known as external additives can be added to the toner particle surfaces as necessary.

  As the external additive used in the present invention, known inorganic fine particles or resin particles are used, but hydrophobized silica fine particles and inorganic fine particles are essential in order to improve charging stability, developability, fluidity and cleaning properties. .

  Silica fine particles used in the present invention are silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, silane coupling agents, silane coupling agents having functional groups, etc. It is desirable to treat with a treating agent such as an organic silicon compound or an organotitanium compound or with various treating agents.

  For example, silane coupling agents typically include dimethyldichlorosilane, trimethylchlorosilane, allyldimethylchlorosilane, hexamethyldisilazane, allylphenyldichlorosilane, benzyldimethylchlorosilane, vinyltriethoxysilane, γ- Examples thereof include methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, divinylchlorosilane and the like.

  The inorganic fine particles preferably have a primary average particle diameter of 0.81 to 2.00 μm. When the thickness is 0.81 μm or more, the toner cleaning property is improved. More preferably, it is 0.81-1.60 micrometers.

  The inorganic fine particles preferably contain titanium, more preferably strontium titanate, from the viewpoint of chargeability and cleaning properties.

  As a method for adding the external additive, a conventionally known method such as a Henschel mixer can be used.

  Hereinafter, the present invention will be specifically described with reference to production examples and examples, but this does not limit the present invention in any way. In addition, all the parts in the following mixing | blending are mass parts.

<Emulsion polymerization / dispersion preparation process>
-Preparation of polymer fine particle dispersion 1-
・ Styrene 73 parts ・ N-Butyl acrylate 25 parts ・ Divinylbenzene 0.3 part ・ Acrylic acid 2 parts ・ Dodecyl mercaptan 0.5 part Mixing and dissolving the above, non-ionic surfactant (manufactured by Sanyo Kasei) : Nonipol 400) 1.5 parts and anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) 2.2 parts dissolved in 120 parts of ion-exchanged water, dispersed and emulsified in a flask for 10 minutes While slowly mixing, add 10 parts of ion-exchanged water in which 2 parts of ammonium persulfate is dissolved, and after purging with nitrogen, heat in an oil bath while stirring the flask until the contents reach 70 ° C. Emulsion polymerization was continued as it was for 4 hours to prepare a polymer fine particle dispersion 1 in which polymer fine particles having an average particle diameter of 0.31 μm were dispersed.

-Preparation of polymer fine particle dispersion 2-
・ Styrene 72 parts ・ N-butyl acrylate 26 parts ・ Divinylbenzene 0.3 part ・ Acrylic acid 2 parts ・ Dodecyl mercaptan 1 part The above mixture was mixed and dissolved into a nonionic surfactant (manufactured by Sanyo Kasei: Nonipol) 400) 1.5 parts and 2.2 parts of an anionic surfactant (Daiichi Kogyo Seiyaku: Neogen SC) dissolved in 120 parts of ion-exchanged water are dispersed and emulsified in a flask, and slowly added for 10 minutes. While mixing, 10 parts of ion-exchanged water in which 2.5 parts of ammonium persulfate was dissolved was added, and after nitrogen substitution, the contents in the flask were heated with an oil bath until the temperature reached 70 ° C. while stirring. Emulsion polymerization was continued for 4 hours to prepare a polymer fine particle dispersion 2 in which polymer fine particles having an average particle diameter of 0.32 μm were dispersed.

-Preparation of polymer fine particle dispersion 3-
・ Styrene 70 parts ・ n-butyl acrylate 28 parts ・ divinylbenzene 0.2 parts ・ acrylic acid 2 parts ・ dodecyl mercaptan 1.8 parts : Nonipol 400) 1.5 parts and anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) 2.2 parts dissolved in 120 parts of ion-exchanged water, dispersed and emulsified in a flask for 10 minutes While slowly mixing, add 10 parts of ion-exchanged water in which 3 parts of ammonium persulfate is dissolved, and after purging with nitrogen, heat in an oil bath while stirring the flask until the contents reach 80 ° C. Emulsion polymerization was continued as it was for 4 hours to prepare a polymer fine particle dispersion 3 in which polymer fine particles having an average particle diameter of 0.29 μm were dispersed.

-Preparation of polymer fine particle dispersion 4-
-74 parts of styrene-23 parts of n-butyl acrylate-1 part of divinylbenzene-2 parts of acrylic acid A mixture of the above and dissolved is 1.5 parts of a nonionic surfactant (Sanyo Kasei: Nonipol 400) and Disperse and emulsify anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) in 120 parts of ion-exchanged water in a flask and mix gently for 10 minutes. 10 parts of ion-exchanged water in which 2 parts of ammonium sulfate was dissolved was added, and the atmosphere was replaced with nitrogen. Then, the contents in the flask were heated with an oil bath until the temperature reached 70 ° C., and the emulsion polymerization was continued for 4 hours. A polymer fine particle dispersion 4 was prepared by dispersing polymer fine particles having an average particle size of 0.34 μm.

-Preparation of polymer fine particle dispersion 5-
-70 parts of styrene-28 parts of n-butyl acrylate-0.1 part of divinylbenzene-2 parts of acrylic acid-2 parts of dodecyl mercaptan 2 parts or more are mixed and dissolved in a nonionic surfactant (manufactured by Sanyo Kasei: Nonipol) 400) 1.5 parts and 2.2 parts of an anionic surfactant (Daiichi Kogyo Seiyaku: Neogen SC) dissolved in 120 parts of ion-exchanged water are dispersed and emulsified in a flask, and slowly added for 10 minutes. While mixing, 10 parts of ion-exchanged water in which 3 parts of ammonium persulfate was dissolved was added, and after nitrogen substitution, the contents in the flask were heated with an oil bath until the temperature reached 90 ° C. while stirring. Emulsion polymerization was continued as it was for a while to prepare a polymer fine particle dispersion 5 in which polymer fine particles having an average particle size of 0.32 μm were dispersed.

-Preparation of polymer fine particle dispersion 6-
-Styrene 76 parts-N-butyl acrylate 20 parts-Divinylbenzene 2 parts-Acrylic acid 2 parts Mixing and dissolving 1.5 parts of nonionic surfactant (manufactured by Sanyo Kasei: Nonipol 400) Disperse and emulsify anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) in 120 parts of ion-exchanged water in a flask and mix gently for 10 minutes. 10 parts of ion-exchanged water in which 1.5 parts of ammonium sulfate was dissolved was added, and after nitrogen substitution, the contents in the flask were heated with an oil bath until the temperature reached 70 ° C. while stirring, and the emulsion polymerization was continued for 4 hours. Continuously, a polymer fine particle dispersion 6 in which polymer fine particles having an average particle diameter of 0.31 μm were dispersed was prepared.

-Preparation of colorant fine particle dispersion-
・ C. I. Pigment Blue 15: 3 20 parts, anionic surfactant (Daiichi Kogyo Seiyaku: Neogen SC) 2 parts, ion-exchanged water 78 parts The above was mixed and dispersed using a sand grinder mill. The average particle diameter of the colorant fine particles contained in this colorant fine particle dispersion was 0.2 μm, and coarse particles exceeding 1 μm were not observed.

-Preparation of release agent fine particle dispersion-
・ Behenyl behenate (Nippon Yushi Co., Ltd .: Unistar M-2222SL) 50 parts ・ Anionic surfactant (Daiichi Kogyo Seiyaku: Neogen SC) 6 parts ・ Ion-exchanged water 200 parts The above was heated to 95 ° C. and homogenizer (IKA Co., Ltd .: Ultra Turrax T50) is dispersed using a pressure discharge type homogenizer, and then release agent fine particle dispersion liquid is obtained by dispersing release agent fine particles having an average particle size of 0.5 μm. Was prepared.

-Preparation of charge control agent particle dispersion-
-20 parts of a metal compound of dialkyl salicylic acid-2 parts of an anionic surfactant (Daiichi Kogyo Seiyaku: Neogen SC)-78 parts of ion-exchanged water The above were mixed and dispersed using a sand grinder mill. The average particle diameter of the charge control agent particles contained in this charge control agent particle dispersion was 0.22 μm, and no coarse particles exceeding 1 μm were observed.

[Example 1]
<Preparation of liquid mixture>
Polymer fine particle dispersion 1 340 parts (solid content)
-Colorant fine particle dispersion 24 parts (solid content)
・ Partner fine particle dispersion 50 parts (solid content)
The above was put into a 2 liter separable flask equipped with a stirrer, a condenser, and a thermometer and stirred. The mixture was adjusted to pH = 5.2 with 1N aqueous potassium hydroxide solution.

<Aggregation process>
200 parts of 20% sodium chloride aqueous solution is added dropwise to the above mixture as a flocculant, heated in a heating oil bath to 50 ° C. with stirring in the flask, and held at 50 ° C. for 1 hour to produce core agglomerated particles. did.

  Further, 60 parts (solid content) of the polymer fine particle dispersion 1 and 2 parts (solid content) of the charge control agent particle dispersion are gradually added here and kept at 50 ° C. for 30 minutes to produce core / shell aggregate particles. did.

<Aging process>
After adding 3 parts of an anionic surfactant (Daiichi Kogyo Seiyaku: Neogen SC) to the core / shell aggregated particle dispersion, the flask was sealed and the mixture was stirred at a peripheral speed of 0.8 m / s up to 95 ° C. Heated and held for 3 hours. Thereafter, the stirring peripheral speed was increased to 1.5 m / s and maintained at 95 ° C. for 2 hours. After cooling, the reaction product was filtered, washed thoroughly with ion exchange water, and then fluidized bed dried at 45 ° C. to obtain cyan toner particles.

<External addition process>
To 100 parts of the toner particles, 1.5 parts of hydrophobic silica fine particles (particle diameter: 17 nm) treated with silicone oil and 0.3 part of strontium titanate (particle diameter: 1.40 μm) were added to a Henschel mixer (FM). -10B). Then, after mixing at a stirring peripheral speed of 3 m / s for 1 minute, mixing at 30 m / s for 5 minutes, and further mixing at 50 m / s for 1 minute, a toner 1 of the present invention was obtained. The physical properties of Toner 1 are shown in Table 1.

[Example 2]
A toner 2 was obtained in the same manner as in Example 1 except that the polymer fine particle dispersion 1 was used instead of the polymer fine particle dispersion 1 during preparation of the mixed solution and during the aggregation step. The physical properties of Toner 2 are shown in Table 1.

Example 3
Toner 3 was obtained in the same manner as in Example 1 except that titanium oxide (particle size: 1.00 μm) was used instead of using strontium titanate in the external addition step. The physical properties of Toner 3 are shown in Table 1.

Example 4
Toner 4 was obtained in the same manner as in Example 1 except that hydrotalcite (particle size: 0.85 μm) was used instead of strontium titanate in the external addition step. The physical properties of Toner 4 are shown in Table 1.

Example 5
Toner 5 was obtained in the same manner as in Example 1 except that titanium oxide (particle size: 0.65 μm) was used instead of strontium titanate in the external addition step. The physical properties of Toner 5 are shown in Table 1.

Example 6
Toner 6 was obtained in the same manner as in Example 1 except that strontium titanate having a particle size of 1.40 μm was used instead of strontium titanate having a particle size of 2.20 μm in the external addition step. The physical properties of Toner 6 are shown in Table 1.

Example 7
Toner 7 was obtained in the same manner as in Example 1 except that the temperature during the aging step was changed from 95 ° C. to 85 ° C. The physical properties of Toner 7 are shown in Table 1.

Example 8
Instead of using the polymer fine particle dispersion 1 at the time of preparing the mixed solution, the polymer fine particle dispersion 3 is used, and instead of using the polymer fine particle dispersion 1 at the aggregation step, the polymer fine particle dispersion 2 is used. Except for the above, Toner 8 was obtained in the same manner as Example 1. The physical properties of Toner 8 are shown in Table 1.

Example 9
A toner 9 was obtained in the same manner as in Example 1 except that the polymer fine particle dispersion 1 was used instead of the polymer fine particle dispersion 1 at the time of preparing the mixed liquid and at the aggregation step. The physical properties of Toner 9 are shown in Table 1.

Example 10
Toner 10 was obtained in the same manner as in Example 9, except that the temperature during the aging step was changed from 95 ° C to 85 ° C. The physical properties of the toner 10 are shown in Table 1.

Example 11
The toner is the same as in Example 1 except that mixing is performed for 1 minute at a peripheral speed of 3 m / s, then mixed for 5 minutes at 30 m / s, and further mixed for 1 minute at 40 m / s. 11 was obtained. The physical properties of the toner 11 are shown in Table 1.

[Comparative Example 1]
Toner 12 was obtained in the same manner as in Example 9, except that the temperature during the aging step was changed from 95 ° C. to 75 ° C., and the holding time at a stirring peripheral speed of 0.8 m / s was changed from 3 hours to 2 hours. The physical properties of the toner 12 are shown in Table 1.

[Comparative Example 2]
Toner 13 was obtained in the same manner as in Example 2 except that the temperature during the aging step was changed from 95 ° C. to 110 ° C. and the holding time at the stirring peripheral speed of 0.8 m / s was changed from 3 hours to 4 hours. The physical properties of the toner 13 are shown in Table 1.

[Comparative Example 3]
A toner 14 was obtained in the same manner as in Example 1 except that the polymer fine particle dispersion 1 was used instead of the polymer fine particle dispersion 1 at the time of preparing the mixed liquid and at the aggregation step. The physical properties of the toner 14 are shown in Table 1.

[Comparative Example 4]
A toner 15 was obtained in the same manner as in Example 1 except that the polymer fine particle dispersion 1 was used instead of the polymer fine particle dispersion 1 during the preparation of the mixed liquid and the aggregation process. The physical properties of the toner 15 are shown in Table 1.

[Comparative Example 5]
The toner 16 was obtained in the same manner as in Example 2 except that the mixing conditions in the external addition step were mixed for 1 minute at a peripheral speed of 3 m / s and then mixed for 5 minutes at 50 m / s. The physical properties of the toner 16 are shown in Table 1.

[Comparative Example 6]
A toner 17 was obtained in the same manner as in Example 9 except that the mixing condition in the external addition step was 1 minute at a peripheral speed of 3 m / s and then 6 minutes at 30 m / s. The physical properties of the toner 17 are shown in Table 1.

[Comparative Example 7]
Toner 18 was obtained in the same manner as in Example 1 except that aging was performed at 0.8 m / s without increasing the stirring peripheral speed during the aging step. The physical properties of the toner 18 are shown in Table 1.

<Image evaluation>
Using LBP-2710 (manufactured by Canon), the produced toner cartridge was filled in the cartridge of the apparatus, and an image having a printing ratio of 20% in a high-temperature and high-humidity environment (30 ° C., 80% RH) was 500 in continuous mode. Printed out to the sheet and evaluated the durability of the toner by the method described below. The evaluation results are shown in Table 2.

(Cleanability)
The streaks on the image generated by the toner slipping through were visually evaluated.
A: Not generated at all B: Slightly generated C: Slightly generated but practically no problem D: Generated and practically problematic

(Image fog)
The fog density (%) is calculated from the difference between the whiteness of the white background portion of the printout image and the whiteness of the transfer paper measured by “REFLECTMETER MODEL TC-6DS” (manufactured by Tokyo Denshoku Co., Ltd.). Image fog was evaluated. An amberlite filter was used as the filter. If the image fog is less than 2.0%, the image is good.
A: Less than 1.0% B: 1.0% or more and less than 2.0% C: 2.0% or more and less than 3.0% D: 3.0% or more

(Gastsuki)
For the evaluation of roughness, a halftone image was output after the endurance of 500 sheets, and the difference in density appearing on the image was visually evaluated.
A: No difference in density is observed B: A slight difference in intensity is observed C: A slight difference in intensity is observed, but there is no practical problem D: A difference in intensity is noticeable, and there is a problem in practical use

(Fixability)
Evaluation was made based on the peelability of a fixed image by a rubbing test of a halftone image having an image density of 0.7 to 0.8. At the initial stage of durability, a halftone patch of 1 cm square was output, rubbed 5 times with a weight of 50 g / cm ² wrapped with the patch sylbon paper, and the density reduction rate was calculated by measuring the image density before and after rubbing. . The image density was measured using a “Macbeth reflection densitometer RD918” (manufactured by Macbeth).
A: Concentration reduction rate less than 10% B: Concentration reduction rate 10% or more and less than 15% C: Concentration reduction rate 15% or more and less than 25% D: Concentration reduction rate 25% or more

Claims (6)

In the emulsion aggregation method toner obtained through a step of aggregating at least polymer fine particles and colorant fine particles to form a fine particle aggregate and a ripening step of causing fusion between the fine particles in the fine particle aggregate,
The weight average particle diameter (D4) is 4 to 8 μm, the average circularity is 0.975 to 0.995, the peak molecular weight (Mp) of the binder resin is 5000 to 60000,
The toner contains at least toner particles, hydrophobized silica fine particles and inorganic fine particles,
In the measurement of the number of particles of 0.6 to 2.0 μm using a flow type particle image analyzer, the measured value of the toner dispersion A ultrasonically dispersed for 5 minutes is C1, and the toner dispersion B is ultrasonically dispersed for 1 minute. When the measured value at is C2, the value C of (C1 / C2) × 100 is 130 to 200,
In Toner Dispersion B, the circularity standard deviation of the number-based particle diameter measured by a flow particle image analyzer is 0.025 to 0.040, and the circularity standard deviation of a particle group having a particle diameter of 50% or more is 50% or more. A toner having a toner content of less than 0.025.   The toner according to claim 1, wherein the binder resin has a peak molecular weight (Mp) of 10,000 to 30,000.   The toner according to claim 1 or 2, wherein the toner has a shape factor SF-1 of 100 to 120.   The toner according to claim 1, wherein the inorganic fine particles have a primary average particle diameter of 0.81 to 2.00 μm.   The toner according to claim 1, wherein the inorganic fine particles contain at least titanium.   6. The toner according to claim 1, wherein the inorganic fine particles are strontium titanate.