JP2005077906A - Electrostatic charge image developing toner, manufacturing method, electrostatic charge image developing developer and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic charge image developing black toner and a method for manufacturing the black toner having excellent coloring property, fixing property, charging property and transfer property, to provide a developer and an image forming method which uses the developer. <P>SOLUTION: The electrostatic charge image black toner and its manufacturing method are characterized in that, in the electrostatic charge image developing toner having a colorant dispersed in a resin, fine particles of a black compound having ≤30 Am<SP>2</SP>/kg magnetic force and magnetic particles having a particle size of ≥0.04 μm and ≤0.35 μm and magnetic force over 30 Am<SP>2</SP>/kg and ≤150 Am<SP>2</SP>/kg are used as the colorant. The developer and the image forming method use the above electrostatic charge image developing black toner. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a black toner for developing an electrostatic image used for developing an electrostatic latent image formed by an electrophotographic method, an electrostatic recording method or the like with a developer, a method for producing the same, a developer for developing an electrostatic image, And an image forming method.

  Methods for visualizing image information through an electrostatic charge image, such as electrophotography, are currently used in various fields. The electrophotographic method includes a charging step, a step of forming an electrostatic charge image on a photoreceptor by exposure, a step of developing an electrostatic latent image with a developer containing toner to form a toner image, and a toner image on a transfer member. Transferring process The toner image is visualized through a fixing process.

  As the developer used here, a two-component developer composed of a toner and a carrier and a one-component developer using a magnetic toner or a nonmagnetic toner alone are known. The toner is usually produced by a kneading and pulverizing method in which a thermoplastic resin is melt-kneaded together with a release agent such as a pigment, a charge control agent, and a wax, cooled, and then finely pulverized and classified. Then, if necessary, inorganic fine particles or organic fine particles are externally added to the toner particle surface in order to improve fluidity and cleaning properties. Although these methods can provide a considerably excellent toner, they have the following problems.

  The toner produced by the kneading and pulverization method has an irregular shape, and the shape and surface structure of the toner slightly changes depending on the pulverization properties of the materials used and the conditions of the pulverization process, so it is difficult to control them. . In addition, the kneading and pulverizing method cannot use materials that are not suitable for kneading and pulverization, and therefore there are significant restrictions on the selection of materials. Specifically, the resin colorant kneaded material is sufficiently brittle and can only be used if it is a material that can be finely pulverized by an economically possible manufacturing apparatus. On the other hand, if the resin colorant kneaded material is made brittle in order to satisfy such requirements, the toner particles are crushed and fine powder is generated or the toner shape is changed by mechanical shearing force applied to the toner in the developing machine. Sometimes.

  These effects are that, in a two-component developer, the fine powder adheres to the carrier surface and accelerates the charging deterioration of the developer, or in a one-component developer, the particle size distribution increases and toner scattering occurs. As a result, the developability is lowered due to the change in toner shape, which causes deterioration of image quality. Further, in a toner in which a large amount of a release agent such as wax is internally added, depending on the combination of the release agent and the thermoplastic resin, the exposure of the release agent to the toner surface often becomes a problem. In particular, in the case of a combination of a resin that has increased elasticity due to a high molecular weight component and is hardly pulverized, and a brittle wax such as polyethylene, pulverization tends to cause pulverization at the interface between the resin and the wax. Exposure will increase. Such a toner is advantageous for releasability at the time of fixing and cleaning of untransferred toner from the surface of the photoreceptor, but the polyethylene on the toner surface receives mechanical force in the developing machine, and the developing roll or photoreceptor , Easily transferred to the carrier and easily contaminated, leading to a decrease in reliability.

  Further, if the toner shape is indefinite, sufficient fluidity cannot be ensured even if a fluidity aid is added. In addition, fine particles on the surface of the toner move to the concave portion of the toner due to mechanical shearing force in the developing machine, and the fluidity is lowered over time. , Cleaning properties will be deteriorated. Further, when the toner collected by the cleaning is returned to the developing machine and used again, the image quality is liable to deteriorate. In order to prevent these problems, increasing the amount of flowable auxiliary particles causes problems such as black spots on the photoreceptor and scattering of the auxiliary particles.

  In recent years, as a method for intentionally controlling the toner shape and the surface structure, a toner production method using an emulsion polymerization aggregation method has been proposed (see, for example, Patent Documents 1 and 2). In these methods, a resin fine particle dispersion is prepared by emulsion polymerization, and a colorant dispersion in which a colorant is dispersed in a solvent is prepared. These are then mixed to form aggregated particles corresponding to the toner particle diameter and heated. The toner is manufactured by fusing and coalescing the aggregated particles. This method makes it possible to easily reduce the particle diameter of the toner and to obtain an extremely excellent toner having a sharp particle size distribution.

    In recent years, the demand for higher image quality has been increasing, and in particular, in order to realize a high-definition image corresponding to the formation of a color image, the toner tends to have a smaller diameter. However, even if the size of the toner is simply reduced with the conventional particle size distribution, the presence of the fine powder side toner causes problems such as carrier and photoconductor contamination and toner scattering, and at the same time achieves high image quality and high reliability. It was difficult to realize. In order to solve these problems, it is important to sharpen the particle size distribution of the toner and to make it possible to reduce the particle size. The agglomeration coalescence method meets these points and is a very advantageous method.

  On the other hand, in recent years, in digital full-color copiers and printers, a color image original is color-separated with B (blue), R (red), and G (green) filters, and then has a dot diameter of 20 to 70 μm corresponding to the original original. There is a method of developing a latent image consisting of Y (yellow), M (magenta), C (cyan), and Bk (black) using a subtractive color mixing action. This method requires a large amount of developer to be transferred as compared with a conventional black-and-white machine, and also needs to cope with a small dot diameter of the latent image. Strength and sharpness of particle size distribution are becoming increasingly important.

    In view of the trend toward higher speed and energy saving of these copying machines, further low-temperature fixability is required as compared with the conventional method. Also from these points, an emulsion polymerization aggregation method suitable for the production of a toner having a sharp particle size distribution and a small particle diameter has attracted attention. Furthermore, the aggregation / fusion coalescence method has only to be easily dispersible in water using, for example, a surfactant or the like, and since there are no further restrictions, the selection range has become extremely wide.

  For example, a method of obtaining a one-component magnetic black toner by adding magnetic powder to a heteroaggregating toner is proposed (for example, see Patent Document 3). However, the toner obtained by this method is agglomerated between magnetic powders and has poor internal dispersibility, and the amount of magnetic powder taken into the toner particles is also limited due to the difference in specific gravity between the magnetic powder and the resin particles. In addition, the black toner for magnetic one component has a large problem in terms of quality and manufacturability such as a deterioration in particle size distribution.

  Further, the magnetic powder inside the toner is likely to be unevenly distributed on the surface of the toner particles or in the vicinity of the surface, so that the chargeability tends to deteriorate. Further, since the fusion of the resin particles is hindered, it is difficult to control the shape and shape distribution, and irregularities are generated on the toner surface, causing problems such as burying of external additives.

As described above, for the agglomerated toner containing the magnetic powder, the selection and production of the magnetic particles as compared with the non-magnetic toner in order to ensure a stable intake amount and ensure uniform dispersion in the toner particles. Currently, it is difficult to select the above conditions.
Japanese Patent Laid-Open No. 63-282275 JP-A-6-250439 JP-A-6-118696 JP 2002-189313 A

  Therefore, the present invention solves the above problems and uses a black toner for developing an electrostatic image excellent in colorability, chargeability, fixability, and transferability, a method for producing the same, a developer, and a developer thereof. An image forming method is to be provided.

The present invention has succeeded in solving the above problems by the following means.
<1> In a toner for developing an electrostatic charge image in which a colorant is dispersed in a resin, the colorant has black compound fine particles having a magnetic force of 30 Am ² / kg or less and a particle size of 0.04 μm to 0.35 μm. A black toner for electrostatic charge development, comprising magnetic particles having a magnetic force of more than 30 Am ² / kg and not more than 150 Am ² / kg.
<2> The colorant is blended in the toner in an amount of 10 to 50% by mass, and the ratio A / B between the black compound fine particle content A and the magnetic particle content B is 0.01 to 0.8. The black toner for electrostatic charge development described in <1> above, which is characterized in that

<3> The surface Fe element strength by XPS analysis (acceleration voltage: 10 kV) of the toner surface is 5.0 atom% or less, and the element strength ratio after etching (before etching / after etching) is 0.5 or more and 1.5. The black toner for electrostatic charge development according to <1> or <2> described above.
<4> The black toner for electrostatic charge development according to any one of <1> to <3>, wherein the toner surface property index represented by the following formula is 1.1 or more and 5.0 or less.
Formula (surface property index value) = (actual value of specific surface area) / (calculated value of specific surface area)
(Specific surface area calculated value) = 6Σ (n × R ² ) / [ρ × Σ (n × R ³ )]
(Where n is the number of particles in the channel at the Coulter counter,
R is the channel particle size at the Coulter counter,
ρ represents the toner density. )

<5> The toner volume average particle size is 3 μm or more and 8 μm or less, the volume particle size distribution index is 1.25 or less, the number particle size distribution index is 1.25 or less, the lower number particle size distribution index is 1.27 or less, and the shape in the image analysis apparatus The coefficient SF1 is 110 or more and 140 or less, the shape factor standard deviation is 15 or less, and the shape factor 160 or more is 20% by number or less. The static according to any one of the above items <1> to <4> Black toner for charge development.
<6> Any of the above <1> to <5>, wherein the release agent component is contained in an amount of 9% to 40%, and the surface release agent exposure rate by XPS is 11% to 40%. The black toner for electrostatic charge development according to claim 1.
<7> The black toner for electrostatic charge development according to any one of <1> to <6>, wherein the aggregate of the colorant particles having a size of 1 μm or more in the cross section of the toner is 5% by number or less.
<8> The black toner for electrostatic charge development according to any one of <1> to <7>, wherein the toner polymer side molecular weight distribution Mz / Mw is 1.5 or more and 3.0 or less.
(Mw represents the weight average molecular weight, and Mz represents the z average molecular weight.)

<9> A resin fine particle dispersion in which at least 1 μm or less of resin fine particles are dispersed and a colorant dispersion are mixed, and the resin fine particles and the colorant are aggregated to form an aggregated particle dispersion, and then the resin fine particles In the black toner for developing an electrostatic charge image, which is heated to a temperature equal to or higher than the glass transition point of the toner to form toner particles, the black compound fine particles having a magnetic force of 30 Am ² / kg or less and a particle size as the colorant Using magnetic particles having a magnetic force of 0.04 μm or more and 0.35 μm or less and a magnetic force exceeding 30 Am ² / kg and not more than 150 Am ² / kg, the pH is controlled to 3.5 or less when forming aggregated particles, and the resin fine particles A method for producing a black toner for electrostatic charge development, comprising adding the magnetic particle dispersion in a range from Tg (glass transition point) to Tg-30 ° C.
<10> A developer for developing an electrostatic charge image, comprising the black toner for electrostatic charge development according to any one of <1> to <8> and a carrier.
<11> A step of forming an electrostatic latent image on the electrostatic latent image carrier, a step of developing the electrostatic latent image with a developer on the developer carrier to form a toner image, and transferring the toner image In the image forming method including the step of transferring onto the body, the step of fixing the toner image on the transfer body, and the cleaning step of removing the toner remaining on the electrostatic latent image carrier, the above <10> An image forming method using the developer described in 1.

  The present invention adopts the above-described configuration to provide a black toner for developing an electrostatic image having a sufficient density of a fixed image and having excellent colorability, no fogging and scattering, chargeability, transferability, and fixability, and production thereof. A method, a developer, and an image forming method using the developer can be provided.

  The present invention uses black compound fine particles having a magnetic force of a specific value or less and a magnetic powder having a specific magnetic force range within a specific particle size range, so that it has excellent chargeability, good coloration, and agglomeration fusion. It is possible to obtain a black toner having a narrow particle size distribution and easy shape control when produced by one method.

The present invention is described in detail below.
As a result of intensive studies to overcome the above problems, the present inventors have found that black compound fine particles having a magnetic force of 30 Am ² / kg or less (hereinafter also referred to as “black metal compound fine particles”) and a particle size of 0. 0.04 μm or more and 0.35 μm or less and magnetic force of more than 30 Am ² / kg and 150 Am ² / kg or less can be used to maintain chargeability under high temperature and high humidity, high colorability, aggregation and coalescence The inventors have found that a black toner having a narrow particle size distribution when produced by the method, easy particle size control, easy shape control and narrow shape distribution can be produced, and the present invention has been completed. The magnetic force in the present invention refers to saturation magnetization when the measurement magnetic field is 796 kA / m.

(Black toner for electrostatic image development)
The black compound fine particles in the present invention have an action to compensate for a decrease in coloring power caused by the high cohesiveness of the magnetic particles. That is, it is considered that the magnetic particles have a higher specific gravity than other aggregated particles and are electrically separated from each other, and when the aggregated coalescence method is used, the magnetic particles are easily precipitated in the aggregation process. In order to avoid this, it is necessary to stir at a higher speed, but at the same time, other particles are less likely to aggregate. Since the black compound fine particles selectively aggregate with the magnetic particles to suppress aggregation between the magnetic particles, it is possible to suppress deterioration in charging property and reduction in coloring power due to aggregation between the magnetic materials. Conceivable.

The magnetic force of the black compound fine particles needs to be 30 Am ² / kg or less. If the magnetic force exceeds 30 Am ² / kg, the dispersibility of the magnetic fine particles in the binder resin is hindered. As a result, the inclusion of the magnetic particles is deteriorated, the reproducibility of the blackness is lowered, and at the same time, the chargeability is broadened and fogging easily occurs. In consideration of controllability and maintainability of chargeability, the preferable range of magnetic force is 20 Am ² / kg or less, and the more preferable range is 10 Am ² / kg or less.

  The center particle diameter of the black metal compound fine particles used in the present invention is preferably in the range of 40 to 500 nm. When the center particle diameter is less than 40 nm, the aggregated toner particles become hard and the shape controllability of the toner in the fusing process is lowered. When the center particle diameter exceeds 500 nm, the content of the black metal compound in the toner decreases, so that sufficient blackness cannot be obtained.

  The magnetic particles in the present invention must be 0.04 μm or more and 0.35 μm or less. When the particle diameter is less than 0.04 μm, it is not good because it causes a decrease in magnetic force and a decrease in coloring power. Further, the aggregation of the particles becomes remarkable, so that the stable incorporation into the toner particles becomes impossible, and the dispersibility in the toner particles also decreases. In addition, when the particle diameter exceeds 0.35 μm, the stability of the particles themselves increases, and stable incorporation into the toner particles becomes impossible. In view of stable uptake and internal dispersibility, the preferred particle size range is 0.07 μm to 0.30 μm, and the still more preferred range is 0.09 μm to 0.25 μm.

The magnetic particles in the present invention are required to have a magnetic force of more than 30 Am ² / kg and 150 Am ² / kg or less. When the magnetic force is 30 Am ² / kg or less, since the magnetic force is insufficient as a magnetic toner, it becomes impossible to achieve stable transportability, making it difficult to use in practice. In addition, when it exceeds 150 Am ² / kg, the cohesive force between the magnetic particles increases, so that the incorporation into the toner particles and the internal uniform dispersibility decrease, so the sharpness, chargeability, and shape of the particle size distribution are reduced. Controllability is poor and not good. Considering these, the preferable range of the magnetic force is 40 Am ² / kg or more and 140 Am ² / kg or less, more preferably 50 Am ² / kg or more and 130 Am ² / kg or less.

  The magnetic particles used in the present invention are not particularly limited as long as they have the above-mentioned magnetic force, such as ferrite, magnetite, reduced iron, cobalt, manganese, nickel, black iron hydroxide, black titanium oxide, hematite and the like. A metal, an alloy, a compound containing these metals, or the like can be used. Among these, it is preferable to use black iron hydroxide, black titanium oxide, and hematite alone or in combination.

  The black compound fine particles used in the present invention are not particularly limited as long as they have the above-mentioned magnetic force. Among them, black iron hydroxide, black titanium oxide, hematite, carbon black are used alone or in combination. It is preferable to use it. Since carbon black, which is a conventional black pigment, has a low resistance, such as 10 Ω · cm, a black compound having a relatively high resistance is preferable for controlling and maintaining the charging property.

  The black iron hydroxide that can be used in the present invention is obtained by subjecting an aqueous iron (II) salt solution such as ferrous sulfate to an alkali treatment with sodium hydroxide or the like after removing the air, and collecting the precipitated powder. Can be manufactured. The black titanium oxide that can be used in the present invention is known as a black pigment for toner (issued on November 20, 1998, “Technology and application development of functional pigments” No. 25). Further, it is preferable that the hematite that can be used in the present invention is manganese-containing hematite. The manganese-containing hematite is formed by magnetizing ferrous sulfate with an alkali and heat treatment to form magnetite particles, and then adding manganese sulfate, followed by further alkali and heat treatment to coat manganese and iron hydroxide. After being filtered, washed with water, dried and pulverized to obtain a black powder, manganese-containing hematite particles can be produced by heat treatment.

  The content of black compound fine particles as a colorant in the toner of the present invention is preferably in the range of 10 to 50% by mass. If the content is less than 10%, sufficient blackness may not be obtained, and if it exceeds 50% by mass, it may not be surely included in the toner and partly exposed. The toner becomes broadly charged, resulting in fogging and scattering.

In the toner of the present invention, the black compound and magnetic particles as a colorant are mixed in the toner in an amount of 10 to 50% by mass, and the ratio A / B of the black compound fine particle content A to the magnetic particles B is 0.01 to 0.00. It is preferable that it is 8 or less.
When the ratio is less than 0.01, the colorability is deteriorated, and the aggregation of the magnetic particles becomes remarkable, and the uptake property, charging property, particle size distribution controllability, and shape controllability may be deteriorated. . When the ratio exceeds 0.8, the magnetic force of the toner itself is reduced, so that it may be difficult to use the toner as a magnetic toner, for example, when stable transportability cannot be obtained. A more preferable range of the ratio is 0.05 to 0.7, and a further preferable range is 0.1 to 0.6.

The toner of the present invention preferably has a small difference in composition between the surface and the interior. The difference in composition between the surface and the inside can be indicated by the Fe strength, which is a constituent component of the magnetic particles. More specifically, the composition difference between the surface and the inside can be determined by XPS analysis of the surface (acceleration voltage 10 KV, current 20 mA, under argon atmosphere). The surface Fe element strength (hereinafter also referred to as “surface Fe strength”) is measured by measuring the toner as it is (before etching), and the inside is irradiated to the toner surface for 30 seconds under the acceleration voltage and current conditions. (After etching) can be measured.
A preferable range of the surface Fe element strength is 5.0 atom% or less, and more preferably 4.0 atom% or less. When the surface Fe element strength exceeds 5.0 atom%, the magnetic particle uptake and internal dispersion uniformity are reduced, sufficient coloring power cannot be obtained, and the chargeability is reduced. It may cause problems such as deterioration and shape controllability.
Further, the Fe element strength ratio after etching (before / after etching) is preferably 0.5 or more and 1.5 or less. When the element strength ratio before and after the treatment is less than 0.5, it indicates that the magnetic particles are unevenly distributed in the vicinity of the toner surface, and when it exceeds 1.5, the element is exposed on the surface or unevenly distributed inside. Represent. The range indicating that the toner is uniformly dispersed is preferably 0.5 or more and 1.5 or less, and more preferably 0.7 or more and 1.3 or less.

The surface property index of the toner of the present invention is preferably from 1.1 to 5.0. If the surface property index exceeds 5, the smoothness of the toner surface may be impaired, and external additives may be buried during external addition, resulting in reduced chargeability. The surface property index is obtained as follows. Measure the particle size of each channel of the Coulter counter and the number of particles of that particle size, calculate the specific surface area by converting each particle to a sphere, and divide the measured specific surface area value by the specific surface area calculation value considering the particle size distribution The surface property index value of the following formula was used.
(Specific surface area calculated value) = 6Σ (n × R ² ) / [ρ × Σ (n × R ³ )]
(Where n is the number of particles in the channel at the Coulter counter,
R is the channel particle size at the Coulter counter,
ρ represents the toner density. )
Next, the specific surface area actual measurement value was obtained by the adsorption method, and the surface property index value was obtained from the following formula.
(Surface property index value) = (actual value of specific surface area) / (calculated value of specific surface area)

The volume average particle diameter D _50v of the toner of the present invention is preferably 3 μm or more and 8 μm or less. When the volume average particle diameter D _50v is _less than 3 μm, the chargeability becomes insufficient and the developability may be deteriorated, and when it exceeds 8 μm, the resolution of the image may be deteriorated. The volume average particle size distribution index GSDv of the toner of the present invention is preferably 1.25 or less, the number average particle size distribution index GSDp is preferably 1.25 or less, and the lower number particle size distribution index is preferably 1.27 or less. When the volume average particle size distribution index GSDv exceeds 1.25, the resolution decreases, the number average particle size distribution index exceeds 1.25, and when the lower number particle size distribution index exceeds 1.27, the chargeability decreases. It also causes image defects such as scattering and fogging.

For the measurement of the particle size and particle size distribution index of the toner of the present invention, for example, the particle size distribution measured using a measuring instrument such as Coulter Counter TAII (manufactured by Beckman-Coulter) or Multisizer II (manufactured by Beckman-Coulter) is used. For the divided particle size range (channel), a cumulative distribution of volume and number is drawn from the smaller diameter side, and the volume average particle diameter D _16V , number average particle diameter D _16P becomes 16% and the volume average becomes 50%. It is defined as a particle size D _50V , a number average particle size D _50p , a volume average particle size D _84V with a cumulative 84%, and a number average particle size D _84p . Using these, the volume average particle size distribution index (GSDv) is determined from (D _84V / D _16V ) ^0.5 , and the number average particle size distribution index (GSDp) is (D _84p / D _16p ) ^0.5 , The index (under GSDp) is calculated from (D _16P / D _50P ).

The shape factor SF1 of the toner of the present invention is preferably in the range of 110 to 140. If SF1 exceeds 140, there may be a disadvantage that transferability is lowered. If SF1 is less than 110, the sphericity increases, so that cleaning of particles having a small particle size may be difficult. A more preferable range of SF1 is 115 or more and 135 or less.
The toner shape factor SF1 is obtained as follows. First, an optical microscopic image of toner spread on a slide glass is taken into a Luzek image analyzer via a video camera, and the maximum length (ML) and projected area (A) of 100 or more toners are measured. 4) The average value of × (ML ² / A) × 100 was obtained and used as the toner shape factor SF1.
The shape factor standard deviation is preferably 15 or less. In the case of exceeding 15, the shape distribution becomes wide, and when the irregular shaped particles increase, many problems such as transfer efficiency, follow characters (missing at the time of transfer), scattering from the developing machine, and charge maintenance may occur. When spherical particles increase, it becomes difficult to obtain stable cleaning characteristics. A more preferable range of the shape factor standard deviation is 12 or less.
Furthermore, it is preferable that those having a shape factor of 160 or more are 20% by number or less. If it exceeds 20% by number, the durability of the toner itself is insufficient in addition to the transferability, chargeability, and scattering from the developing machine, and the photoreceptor, charging member, and transfer member may be contaminated due to destruction. There may be many. A more preferable ratio of particles having a shape factor of 160 or more is 10% by number or less.

  The release agent component of the toner of the present invention is preferably contained in an amount of 9 to 40% by mass. When the content of the release agent contained in the toner for developing an electrostatic charge image is less than 9% by mass, image defects such as black spots and black streaks due to adhesion of the release agent component to the photoreceptor are suppressed, but fixing performance, In particular, there may be a problem in peeling performance at high temperatures. On the other hand, when the amount exceeds 40% by mass, the surface mold release agent exposure rate increases, and image defects such as black spots and black streaks due to adhesion of the mold release agent component may become a problem. Furthermore, preferable content is 9-30 mass%.

  The surface release agent exposure rate by XPS (X-ray photoelectron spectroscopy) is preferably 11% or more and 40% or less. If the surface release agent exposure rate is less than 11%, there is a case where long-term maintainability is difficult although there is no influence on the fixing performance at the beginning. Further, when the fixing device deteriorates, it may adversely affect the offset on the high temperature side and the fixed image strength on the low temperature side. On the other hand, if it exceeds 40%, the fixing performance is not affected, but the toner on the carrier, the developing roll, the photoconductor, etc. may be fixed as a foreign substance, so-called filming may occur. In some cases, the external additive added to impart fluidity is likely to be buried in the toner. A preferable exposure rate is 13 to 30%. The exposure rate of the release agent on the surface of the toner for developing an electrostatic charge image is measured using a measuring machine such as an X-ray photoelectron spectrometer (XPS, JPS-9000MX) manufactured by JEOL Co., Ltd. The peak due to can be separated and quantified.

  The aggregate of colorant particles of 1 μm or more in the toner cross section is preferably 5% by number or less. When the aggregate exceeds 5% by number, charging characteristics, coloring power, shape distribution, and the like may be deteriorated. Further, the preferred range is 3% by number or less. Aggregates of colorant particles inside the toner are calculated by taking an image obtained with a transmission electron microscope into the image analyzer and counting the colorant particles observed with 50 or more toner particles. Is done.

The molecular weight (Mw) of the toner of the present invention is preferably from 40,000 to 300,000. The molecular weight distribution (Mz / Mw) is preferably 1.5 or more and 3.0 or less. Here, Mw represents a weight average molecular weight, and Mz represents a z average molecular weight, both of which can be measured by dissolving a toner particle in a THF solvent and using a known GPC measuring instrument.
If Mw is less than 40,000, the toner elastic force may be reduced, causing problems in fixability at high temperatures, and if Mw exceeds 300,000, the toner particles may become hard, so low temperature fixability and shape controllability. May cause problems. A more preferable range of Mw is 50,000 to 250,000.
On the other hand, if Mz / Mw is less than 1.5, the toner elastic force may be reduced, which may cause a problem in fixability at high temperature. There may be a problem in the fixing property and shape controllability. A more preferable range is 1.7 or more and 2.8 or less.

  The charge amount of the toner of the present invention is preferably in the range of 20 to 40 μC / g in absolute value. When the charge amount is less than 20 μC / g, background stains (fogging) are likely to occur, and when it exceeds 40 μC / g, the image density is likely to decrease. A more preferable range of the charge amount is 25 to 35 μC / g. The ratio of the charge amount in summer (high temperature and high humidity) of the toner of the present invention to the charge amount in winter (low temperature and low humidity) is preferably in the range of 0.5 to 1.5. Outside this range, the dependence of the charge amount on the environment may become strong, and charging stability is lacking, which is not preferable for practical use. A more preferable range of the charge amount ratio is 0.7 to 1.3.

The black toner having the above characteristics can be easily manufactured, for example, by the following method. That is, a resin fine particle dispersion in which at least 1 μm or less of resin fine particles are dispersed with an ionic surfactant, and a colorant dispersion containing no magnetic particles dispersed with an ionic surfactant having the opposite polarity. And the release agent dispersion. When both are mixed to form hetero-aggregation to form aggregated particles corresponding to the toner diameter, the colorant dispersion containing magnetic particles is controlled while controlling the pH of the liquid to 3.5 or lower. The colorant dispersion containing the magnetic particles is gradually added in the range from the glass transition point (Tg) of the resin fine particles to a temperature 30 ° C. lower than the glass transition point (Tg to Tg-30 ° C.). Subsequently, the adjusted aggregated particle dispersion is heated to a temperature equal to or higher than the Tg, fused and united, washed and dried to obtain spherical toner particles.
Here, “gradually” means that it is added continuously, intermittently or stepwise and not added all at once. If it is added at a time, the magnetic particles may be settled or agglomerate between the magnetic particles. The pH control means pH control after mixing the raw material dispersion and / or during the heteroaggregation by adding a flocculant and heating.
The colorant of the colorant dispersion not containing the magnetic particles is black compound fine particles having a magnetic force of 30 Am ² / kg or less, and the magnetic particles have a particle size of 0.04 μm to 0.35 μm. There are particles having a magnetic force of more than 30 Am ² / kg and not more than 150 Am ² / kg.
The temperature at which the colorant dispersion having magnetic particles is added to the mixed liquid of the resin fine particle dispersion and the colorant dispersion not containing magnetic particles is 30 ° C. lower than Tg to Tg of the resin fine particles. The addition is necessary in terms of improving the incorporation of the magnetic particles into the aggregated particles.
When the addition temperature exceeds Tg (° C.), the progress of aggregation of the resin particles is remarkable, so that it is difficult to uniformly incorporate the magnetic particles into the aggregated particles. There is a problem that the sedimentation of the particles or the agglomeration speed between the magnetic particles is too large to be uniformly taken in.
The resin fine particle dispersion is generally produced by emulsion polymerization or the like.

  By carrying out as described above, the magnetic particles can be uniformly dispersed in the binder resin, so that the magnetic powder can be taken in and dispersed in the toner, the toner colorability, the chargeability, the shape controllability, the particle size. A black toner excellent in distribution controllability can be easily produced.

In addition, in the initial stage of the agglomeration process, the production process is performed by preliminarily shifting the balance of the amount of each ionic dispersant, and for example, an inorganic metal salt such as calcium nitrate or a polymer of an inorganic metal salt such as polyaluminum chloride. This is neutralized to ions and the glass transition point Tg to Tg-30 of the glass transition point Tg to Tg-30 is formed as the second step after forming and stabilizing the first-stage matrix aggregation at a temperature of −30 ° C. or lower. Aggregated particles are formed by adding a resin particle dispersion treated with a dispersant having a polarity and an amount so as to compensate for the deviation in pH balance while maintaining the pH at 3.5 or lower in the range of ° C. Then, after stabilizing at a higher temperature, the particles added in the second stage of agglomeration by heating above the glass transition point of the resin may be fused and coalesced while adhering to the surface of the base agglomerated particles. good.
The pH needs to be 3.5 or less, and if it exceeds pH 3.5, the formation rate of aggregated particles is reduced, which may cause a non-uniform structure.
The pH is preferably 3.0 or less, more preferably 2.8 or less, from the viewpoint of controlling the aggregation rate and forming a uniform structure.
The pH can be adjusted by adding a pH adjuster, and the pH adjuster is not particularly limited, and general inorganic acids such as nitric acid and hydrochloric acid can be used.

  There are no particular restrictions on the polymer of resin fine particles used in the production of the toner of the present invention, but examples include styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, and acrylic acid n. Esters having a vinyl group such as propyl, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate Vinyl nitriles such as acrylonitrile and methacrylonitrile; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; ethylene, propylene and butadiene Polymers or copolymers obtained by combining them two or more made of monomers such as polyolefins like, can further be used mixtures thereof. In addition, epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, etc., non-vinyl condensation resins, or mixtures thereof with the vinyl resins, or vinyl monomers in the presence of these resins Graft polymers obtained by polymerizing can be used.

The Tg of the resin fine particles is preferably 45 to 65 ° C. from the viewpoint of toner production energy reduction, toner storage stability, shape controllability, low-temperature fixability, and image storage stability, and more preferably 48 to 60 ° C. Preferably there is. By setting the Tg range, an inexpensive high-quality toner that satisfies the above characteristics can be provided.
The weight average molecular weight (Mw) of the polymer used as the resin fine particles is preferably 40000 to 300000, more preferably 60000 to 200000, from the viewpoints of shape controllability and fixing characteristics. The average molecular weight (Z) of the polymer to be the resin fine particles is preferably 60000 to 900000, more preferably 100000 to 700000, from the viewpoint of shape controllability and fixing characteristics.

  In the case of the vinyl monomer, emulsion polymerization using an ionic surfactant or the like can be carried out to prepare a resin fine particle dispersion, and in the case of other resins, it is oily and the solubility in water is compared. If the resin is soluble in a low solvent, the resin is dissolved in those solvents and dispersed in water with a disperser such as a homogenizer together with an ionic surfactant or polymer electrolyte in water, and then heated or decompressed. A resin fine particle dispersion can be prepared by evaporating the solvent. The particle diameter of the obtained resin fine particles can be measured, for example, with a laser diffraction particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.).

  In the toner of the present invention, 9 to 40% by mass of a release agent can be contained in the toner particles. The release agent dispersion may be mixed with the resin fine particle dispersion and the colorant dispersion to contain the release agent in the aggregated particles. In addition, when a release agent dispersion is added to the aggregated particle dispersion to attach the release agent to the surface of the aggregated particles, an additional particle dispersion is added thereafter so that the release agent is not exposed on the toner surface. It is preferable to ensure charging property and durability.

  As the release agent that can be used in the present invention, a substance having a main maximum peak measured in accordance with ASTM D3418-8 at 50 to 140 ° C. is preferable. If it is less than 50 ° C., an offset tends to occur during fixing. On the other hand, if the temperature exceeds 140 ° C., the fixing temperature becomes high, the smoothness of the surface of the fixed image cannot be obtained, and the glossiness is impaired. For the measurement of the main maximum peak of the present invention, for example, DSC-7 manufactured by Perkin Elmer is used. The temperature correction of the detection part of the apparatus uses the melting points of indium and zinc, and the correction of heat quantity uses the heat of fusion of indium. As the sample, an aluminum pan is used, an empty pan is set as a control, and the measurement is performed at a heating rate of 10 ° C./min.

  Specific examples of the release agent used in the present invention include low molecular weight polyolefins such as polyethylene, polypropylene, and polybutene, silicones that exhibit a softening point upon heating, oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide Fatty acid amides such as carnauba wax, rice wax, candelilla wax, plant wax such as tree wax, jojoba oil, animal wax such as beeswax, montan wax, ozokerite, ceresin, paraffin wax, micro Minerals such as crystallin wax, microcrystalline wax, Fischer-Tropsch wax, petroleum-based waxes, and modified products thereof can be used.

  These waxes are dispersed in water together with ionic surfactants, polymer electrolytes such as polymer acids and polymer bases, and heated with a homogenizer or pressure discharge type disperser that can be heated to the melting point or higher and subjected to strong shearing. Can be The preferred particle size is 1 μm or less, and more preferably 0.6 μm or less, because the uptake of the release agent during aggregation can be improved. The particle size of the obtained release agent particle dispersion is measured, for example, with a laser diffraction particle size distribution measuring device (LA-700, manufactured by Horiba, Ltd.).

    The toner of the present invention can be blended with a charge control agent in order to further improve and stabilize the chargeability. As the charge control agent, various commonly used charge control agents such as quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium and triphenylmethane pigments can be used. In order to control the ionic strength that affects the stability of aggregation and fusion and to reduce wastewater contamination, it is preferable to use a material that is difficult to dissolve in water.

  In the toner of the present invention, inorganic fine particles can be attached by a wet method in order to stabilize the chargeability. Examples of inorganic fine particles to be added include all those usually used as external additives on the toner surface such as silica, alumina, titania, calcium carbonate, magnesium carbonate, tricalcium phosphate, ionic surfactants and polymers. It can be used by dispersing with an acid or a polymer base. In addition, colloidal silica, alumina sol, etc. dispersed in water in advance can also be used.

  In addition, the toner of the present invention is used for the purpose of imparting fluidity and improving cleaning properties, after drying the toner particles in the same manner as normal toner, inorganic particles such as silica, alumina, titania, calcium carbonate, vinyl resin, polyester, silicone, etc. These resin particles can be externally added to the toner particle surface by applying a shearing force in a dry state.

In the production of the toner of the present invention, examples of the surfactant used for the purpose of emulsion polymerization, pigment dispersion, resin fine particle dispersion, release agent dispersion, aggregation thereof, or stabilization thereof include sulfate ester salt, sulfone Anionic surfactants such as acid salts, phosphate esters and soaps, and cationic surfactants such as amine salts and quaternary ammonium salts can be used, and polyethylene glycols and alkylphenols can be used. It is also effective to use a nonionic surfactant such as an ethylene oxide adduct system or a polyhydric alcohol system in combination. Of these, those having sulfate radicals such as sulfate ester salts are preferably used.
As the dispersing means, a general means such as a rotary shear type homogenizer, a ball mill having a media, a sand mill, or a dyno mill can be used.

  After completion of the aggregation and fusion, desired toner particles are obtained through an arbitrary washing step, solid-liquid separation step, and drying step. In the washing step, it is preferable to perform sufficient substitution washing with ion-exchanged water from the viewpoint of chargeability. . Moreover, although there is no restriction | limiting in particular in a solid-liquid separation process, suction filtration, pressure filtration, etc. are used preferably from the point of productivity. The drying process is not particularly limited, but freeze drying, air flow drying, fluidized drying, vibration fluidized drying, etc. are preferably used from the viewpoint of productivity.

(Static charge image developer)
The electrostatic image developer used in the present invention is not particularly limited except that it contains the toner for developing an electrostatic image, and can have an appropriate component composition according to the purpose. The electrostatic image developer is prepared as a one-component electrostatic image developer when the above-mentioned toner for developing an electrostatic image is used alone, and two-component electrostatic image developer when used in combination with a carrier. It is prepared as an agent.

  The carrier is not particularly limited, and examples thereof include known carriers. For example, known carriers such as resin-coated carriers described in JP-A Nos. 62-39879 and 56-11461 are known. A carrier or the like can be used.

Specific examples of the carrier include the following resin-coated carriers. That is, as the core particle of the carrier, usual iron powder, ferrite, magnetite moldings and the like can be mentioned, and the average particle size is preferably in the range of about 30 to 200 μm.
Examples of the coating resin for the core particles include styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, and 2-ethylhexyl acrylate. Α-methylene fatty acid monocarboxylic acids such as methyl methacrylate, methacrylic acid, n-propyl lauryl methacrylate 2-ethylhexyl; nitrogen-containing acrylics such as dimethylaminoethyl methacrylate; vinyl nitriles such as acrylonitrile and methacrylonitrile Vinyl pyridines such as 2-vinyl pyridine and 4-vinyl pyridine; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isoprobenyl ketone; Ketones; olefins such as ethylene and propylene; vinyl-based fluorine-containing monomers such as vinylidene fluoride, tetrafluoroethylene and hexafluoroethylene; homopolymers such as, or copolymers composed of two or more types of monomers,

Further, silicones such as methylsilicone and methylphenylsilicone, polyesters containing bisphenol, glycol and the like, epoxy resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, polycarbonate resins and the like can be mentioned. These resins may be used alone or in combination of two or more.
The amount of the coating resin is preferably in the range of about 0.1 to 10 parts by mass, and more preferably in the range of 0.5 to 3.0 parts by mass with respect to the core particles.

  In the production of the carrier, a heating kneader, a heating Henschel mixer, a UM mixer, or the like can be used. Depending on the amount of the coating resin, a heating fluidized rolling bed, a heating kiln, or the like can be used. it can.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited at all. In addition, the average particle diameter of the resin particles, the colorant particles, and the release agent particles was measured using a laser diffraction particle size distribution measuring apparatus (Horiba, Ltd .: LA-700). Further, the molecular weight of the resin in the resin particles and the toner particles was measured by using gel permeation chromatography (manufactured by Tosoh Corporation: HLC-8120GPC). Tables 1 and 2 show the test results of toners and developers obtained in Examples and Comparative Examples.

(Preparation of resin fine particles 1)
Styrene (manufactured by Wako Pure Chemical Industries, Ltd.) 330 parts by mass n-butyl acrylate (manufactured by Wako Pure Chemical Industries, Ltd.) 70 parts by mass β-carboxyethyl acrylate (manufactured by Rhodia Nikka Co., Ltd.) 9 parts by mass 1 ′, 10-decanediol diacrylate (Shin Nakamura) 1.5 parts by mass Dodecanethiol (manufactured by Wako Pure Chemical Industries, Ltd.) 2.7 parts by mass The above components are mixed and dissolved to prepare 413.2 parts by mass of a raw material solution, and an anionic surfactant (Dowfax) (Manufactured by Rhodia) 4 parts by mass dissolved in ion-exchanged water 550 parts by mass, the above raw material solution is added, dispersed and emulsified in a flask, and slowly stirred and mixed for 10 minutes. 50 parts by mass of ion-exchanged water dissolved in water was added, and then the inside of the system was sufficiently replaced with nitrogen, and then the inside of the system reached 70 ° C. with an oil bath while stirring the flask. The emulsion polymerization was continued for 5 hours to obtain an anionic fine resin particle dispersion. The obtained resin fine particles had a center particle size of 220 nm, a solid content of 42%, a glass transition point of 53.0 ° C., a weight average molecular weight Mw of 31000, and a Z average molecular weight of 78,000.

(Preparation of resin fine particles 2)
Styrene (manufactured by Wako Pure Chemical Industries, Ltd.) 330 parts by mass n-butyl acrylate (manufactured by Wako Pure Chemical Industries, Ltd.) 70 parts by mass β-carboxyethyl acrylate (manufactured by Rhodia Nikka Co., Ltd.) 9 parts by mass 1 ′, 10-decanediol diacrylate (Shin Nakamura) 1.2 parts by mass The above ingredients are mixed and dissolved to prepare 410.2 parts by mass of a raw material solution, and 8 parts by mass of an anionic surfactant (Dowfax, Rhodia) are added to 550 parts by mass of ion-exchanged water. The raw material solution is added to the part dissolved in the flask, dispersed and emulsified in a flask, and while slowly stirring and mixing for 10 minutes, 50 parts by mass of ion-exchanged water in which 3 parts by mass of ammonium persulfate is dissolved is added. After sufficiently replacing the system with nitrogen, the system was heated with an oil bath while stirring the flask until the system reached 65 ° C., and the emulsion polymerization was continued for 5 hours. To obtain an anionic resin particle dispersion.
The obtained resin fine particles had a center particle size of 200 nm, a solid content of 41%, a glass transition point of 53.5 ° C., a weight average molecular weight Mw of 70000, and a Z average molecular weight of 2200000.

(Preparation of manganese-containing hematite)
300 liters of ferrous sulfate having a concentration of 1.30 mol / liter is added to 200 liters of water and 60 liters of a 15.5N aqueous sodium hydroxide solution prepared in advance in a reactor equipped with a stirrer. An aqueous ferrous salt solution containing ferrous hydroxide was produced at 85 ° C.
With respect to the ferrous salt aqueous solution containing ferrous hydroxide, 270 liters of air was aerated for 90 minutes at a temperature of 90 ° C. to generate magnetite particles.
Next, 100 liters of an aqueous ferrous sulfate solution having a concentration of 1.3 mol / liter and 100 liters of an aqueous manganese sulfate solution having a concentration of 1.3 mol / liter are added to 500 liters of an aqueous suspension containing 29.6 kg of the magnetite particles. Mn amount corresponds to 20 atomic% with respect to Fe and Mn) and 46 liters of 11.2N sodium hydroxide aqueous solution (corresponding to the amount of neutralizing added Mn amount and added Fe ²⁺ amount), Magnetite particles formed by coating with manganese and iron hydroxide by passing 180 liters of air at a pH value of 13 or more and a temperature of 90 ° C. for 180 minutes.
The produced particles were filtered, washed with water, dried and pulverized by a conventional method to obtain a black powder. This black powder was passed through a continuous electric furnace having a ceramic furnace core tube and given an average residence time of 900 ° C. for 60 minutes in air to obtain manganese-containing hematite.
The obtained manganese-containing hematite had an average particle size of 0.25 μm, and as a result of fluorescent X-ray analysis, the manganese content was 14.8% by mass. As a result of X-ray diffraction, a hematite peak was observed.

(Preparation of colorant dispersion (1))
Manganese-containing hematite (magnetic force 0 Am ² / g) 25 parts by mass Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku Co., Ltd.) 5 parts by mass Ion-exchanged water 70 parts by mass , Manufactured by IKA Co., Ltd.) for 10 minutes, and then subjected to a dispersion treatment at a pressure of 245 MPa for 15 minutes using an opposing collision type wet pulverizer (Ultimizer, manufactured by Sugino Machine Co., Ltd.) to obtain a colorant dispersion (1). .
The center particle diameter of the colorant in the obtained colorant dispersion (1) was 300 nm.

(Preparation of colorant dispersion (2))
Black iron hydroxide (manufactured by Orient Chemical Co., Ltd., magnetic force 0 Am ² / g) 25 parts by mass Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku) 5 parts by mass Ion-exchanged water 70 parts by mass After pre-dispersing for 10 minutes with (Ultra Turrax, manufactured by IKA), a colorant dispersion (2) is subjected to a dispersion treatment at a pressure of 245 Mpa for 15 minutes using a counter collision type wet pulverizer (Ultimizer, manufactured by Sugino Machine). )
The center particle size of the colorant in the obtained colorant dispersion (2) was 130 nm.

(Preparation of colorant dispersion (3))
Black titanium oxide (manufactured by Titanium Industry Co., Ltd., magnetic force 0 Am ² / g) 25 parts by mass Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku Co., Ltd.) 5 parts by mass Ion-exchanged water 70 parts by mass After pre-dispersing for 10 minutes with Ultra Tarrax (manufactured by IKA), a colorant dispersion (3) is subjected to dispersion treatment at a pressure of 245 MPa for 15 minutes using a counter-impact type wet pulverizer (Ultimizer, Sugino Machine). Got.
The center particle size of the colorant in the obtained colorant dispersion (3) was 150 nm.

(Preparation of colorant dispersion (4))
Carbon black (R330, manufactured by Cabot Corporation) 25 parts by mass Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku) 5 parts by mass Ion-exchanged water 70 parts by mass The above ingredients were mixed and homogenizer (Ultra Turrax, manufactured by IKA) ) For 10 minutes and then subjected to a dispersion treatment at a pressure of 245 MPa for 15 minutes using an opposing collision type wet pulverizer (Ultimizer, Sugino Machine Co., Ltd.) to obtain a colorant dispersion (4).
The center particle size of the colorant in the obtained colorant dispersion (4) was 150 nm.

(Preparation of colorant dispersion (5))
Magnetite (manufactured by Toda Kogyo Co., Ltd., particle size 90 nm, magnetic force 80 Am ² / g) 25 parts by mass Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku) 5 parts by mass Ion-exchanged water 70 parts by mass After pre-dispersing for 10 minutes with a homogenizer (Ultra Turrax, manufactured by IKA), a dispersion of colorant is performed by carrying out a dispersion treatment at a pressure of 245 MPa for 15 minutes using an opposed collision type wet pulverizer (Ultimizer, manufactured by Sugino Machine). 5) was obtained.
The center particle diameter of the colorant in the obtained colorant dispersion (5) was 270 nm.

(Preparation of colorant dispersion (6))
Magnetite (manufactured by Toda Kogyo Co., Ltd., particle size 200 nm, magnetic force 125 Am ² / g) 25 parts by mass Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku) 5 parts by mass Ion-exchanged water 70 parts by mass After pre-dispersing for 10 minutes with a homogenizer (Ultra Turrax, manufactured by IKA), a dispersion of colorant is performed by carrying out a dispersion treatment at a pressure of 245 MPa for 15 minutes using an opposed collision type wet pulverizer (Ultimizer, manufactured by Sugino Machine). 6) was obtained.
The center particle diameter of the colorant in the obtained colorant dispersion (6) was 300 nm.

(Preparation of colorant dispersion (7))
Magnetite (manufactured by Toda Kogyo Co., Ltd., particle size 45 nm, magnetic force 65 Am ² / g) 25 parts by mass Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku) 5 parts by mass Ion-exchanged water 70 parts by mass After pre-dispersing for 10 minutes with a homogenizer (Ultra Turrax, manufactured by IKA), a dispersion of colorant is performed by carrying out a dispersion treatment at a pressure of 245 MPa for 15 minutes using an opposed collision type wet pulverizer (Ultimizer, manufactured by Sugino Machine). 7) was obtained.
The center particle diameter of the colorant in the obtained colorant dispersion (7) was 250 nm.

(Preparation of colorant dispersion (8))
Magnetite (manufactured by Toda Kogyo Co., Ltd., particle size 300 nm, magnetic force 150 Am ² / g) 25 parts by mass Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku) 5 parts by mass Ion-exchanged water 70 parts by mass After pre-dispersing for 10 minutes with a homogenizer (Ultra Turrax, manufactured by IKA), a dispersion of colorant is performed by carrying out a dispersion treatment at a pressure of 245 MPa for 15 minutes using an opposed collision type wet pulverizer (Ultimizer, manufactured by Sugino Machine). 8) was obtained.
The center particle size of the colorant in the obtained colorant dispersion (8) was 250 nm.

(Preparation of colorant dispersion (9))
Black titanium hydroxide (particle size 300 nm, magnetic force 25 Am ² / g) 25 parts by mass Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku) 5 parts by mass Ion-exchanged water 70 parts by mass The above ingredients are mixed and homogenizer ( After pre-dispersing for 10 minutes with Ultra Tarrax (manufactured by IKA), colorant dispersion (9) is subjected to dispersion treatment at a pressure of 245 Mpa for 15 minutes using a counter collision type wet pulverizer (Ultimizer, Sugino Machine). Got.
The center particle size of the colorant in the obtained colorant dispersion (9) was 240 nm.

(Preparation of colorant dispersion (10))
Magnetite (particle size 300 nm, magnetic force 40 Am ² / g) 25 parts by mass Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku) 5 parts by weight Ion-exchanged water 70 parts by weight , Manufactured by IKA Co., Ltd.) for 10 minutes, and then subjected to a dispersion treatment at a pressure of 245 MPa for 15 minutes using an opposing collision type wet pulverizer (Ultimizer, manufactured by Sugino Machine Co., Ltd.) to obtain a colorant dispersion (10). .
The center particle diameter of the colorant in the obtained colorant dispersion (10) was 240 nm.

(Preparation of colorant dispersion (11))
Magnetite (manufactured by Toda Kogyo Co., Ltd., particle size 300 nm, magnetic force 155 Am ² / g) 25 parts by mass Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku) 5 parts by mass Ion-exchanged water 70 parts by mass After pre-dispersing for 10 minutes with a homogenizer (Ultra Turrax, manufactured by IKA), a dispersion of colorant (15 ml) was performed at a pressure of 245 Mpa using a counter-impact type wet pulverizer (Ultimizer, manufactured by Sugino Machine) (colorant dispersion ( 11) was obtained.
The center particle size of the colorant in the obtained colorant dispersion (11) was 250 nm.

(Preparation of release agent dispersion)
Polyethylene wax (PW850, manufactured by Toyo Petrolite Co., Ltd.) 200 parts by mass Ion surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 10 parts by mass Deionized water 630 parts by mass After heating the above components to 130 ° C, Dispersion treatment was performed for 30 minutes under a pressure of 560 kg / cm ² using a Gorin homogenizer (manufactured by Gorin). Then, it cooled to 50 degreeC and the mold release agent dispersion liquid was obtained.
The center particle diameter of the release agent in the obtained release agent dispersion was 200 nm, and the solid content concentration was 25% by mass.

[Example 1]
Resin fine particle (1) dispersion 80 parts by weight Resin fine particle (2) dispersion 20 parts by weight Colorant dispersion (1) 15 parts by weight Colorant dispersion (5) 50 parts by weight Release agent dispersion 36 parts by weight Magnetic particles In the round stainless steel flask, the above components other than the colorant dispersion containing bismuth are kept at a temperature lower than 30 ° C. lower than the Tg of the resin fine particles (1) using Ultra Turrax (T50, manufactured by IKA). While fully mixed and dispersed. Next, 0.4 parts by mass of polyaluminum chloride was added to this dispersion, and the dispersion operation was continued with an ultra turrax.
Thereafter, a temperature increase was observed due to heat generated by the disperser, and a colorant dispersion containing magnetic particles was added at a temperature of Tg-30 ° C. or higher of the resin particles. When the pH of the liquid in the disperser was measured, the pH was 3.6. Therefore, the dispersion was terminated by adding a 0.3 M nitric acid aqueous solution to adjust the pH to 2.6. Thereafter, the flask was heated to 50 ° C. with stirring in an oil bath for heating. After maintaining at 50 ° C. for 60 minutes, 31 parts by mass of resin fine particle dispersion (1) was gradually added. Thereafter, the pH of the system was adjusted to 5.4 with a 0.5 N aqueous sodium hydroxide solution, and then the stainless steel flask was sealed and heated to 96 ° C. while continuing to stir using a magnetic seal for 5 hours. Retained.

After completion of the reaction, the mixture was cooled, filtered, sufficiently washed with ion exchange water, and then subjected to solid-liquid separation by Nutsche suction filtration.
This was further redispersed in 3 liters of ion exchange water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. This was repeated five more times, and when the pH of the filtrate was 6.85, the electrical conductivity was 9.3 μS / cm, and the surface tension was 70.5 Nm, solid-liquid separation was performed using No5A filter paper by Nutsche suction filtration. It was.
Next, vacuum drying was continued for 12 hours to obtain black toner particles of Example 1.
The resulting black toner particles have a volume average particle size D50v of 6.7 μm, a volume average particle size distribution index GSDv of 1.20, a number average particle size distribution index GSDp of 1.24, SF1 of 129.7 and a potato-like (potato) Undefined shape). Further, Mw of the toner was 180,000, Mz was 500,000, and Mz / Mw was 2.8.

[Example 2]
Example 1 Example 1 except that the blending of the colorant dispersion (1) was changed from 15 parts by weight to 50 parts by weight and the blending of the colorant dispersion (5) was changed from 50 parts by weight to 15 parts by weight. In the same manner, black toner particles of Example 2 were obtained.
The black toner particles obtained had a volume average particle size D50v of 6.5 μm, a volume average particle size distribution index GSDv of 1.21, a number average particle size distribution index GSDp of 1.24, and SF1 of 130.5 and were potato-like. . Further, Mw of the toner was 182000, Mz was 510000, and Mz / Mw was 2.8.

Example 3
In Example 1, the same procedure as in Example 1 was performed, except that the colorant dispersion (1) was changed to the colorant dispersion (2) and the colorant dispersion (5) was changed to the colorant dispersion (6). The black toner particles of Example 3 were obtained.
The black toner particles obtained had a volume average particle size D50v of 6.3 μm, a volume average particle size distribution index GSDv of 1.21, a number average particle size distribution index GSDp of 1.24, and SF1 of 130.3 and were potato-like. . Further, Mw of the toner was 180,000, Mz was 4950000, and Mz / Mw was 2.8.

Example 4
In Example 1, the same procedure as in Example 1 was performed except that the colorant dispersion (1) was changed to the colorant dispersion (3) and the colorant dispersion (5) was changed to the colorant dispersion (7). The black toner particles of Example 4 were obtained.
The resulting black toner particles had a volume average particle size D50v of 6.6 μm, a volume average particle size distribution index GSDv of 1.22, a number average particle size distribution index GSDp of 1.25 and SF1 of 128.3. Further, Mw of the toner was 180,000, Mz was 500,000, and Mz / Mw was 2.8.

Example 5
In Example 1, the same procedure as in Example 1 was performed except that the colorant dispersion (1) was changed to the colorant dispersion (4) and the colorant dispersion (5) was changed to the colorant dispersion (8). The black toner particles of Example 5 were obtained.
The obtained black toner particles had a volume average particle size D50v of 6.4 μm, a volume average particle size distribution index GSDv of 1.20, a number average particle size distribution index GSDp of 1.23 and SF1 of 129.5. Further, Mw of the toner was 180,000, Mz was 504000, and Mz / Mw was 2.8.

Example 6
In Example 1, the colorant dispersion (1) was changed to the colorant dispersion (4), the colorant dispersion (5) was changed to the colorant dispersion (8), and the pH at 96 ° C. was 4. Black toner particles of Example 6 were obtained in the same manner as Example 1 except that the step of adjusting to 0 was performed.
The obtained black toner particles had a volume average particle size D50v of 6.5 μm, a volume average particle size distribution index GSDv of 1.20, a number average particle size distribution index GSDp of 1.23 and SF1 of 119.5. Further, Mw of the toner was 183000, Mz was 506000, and Mz / Mw was 2.8.

Example 7
Resin solid content obtained by preparation of resin fine particle dispersion (1) 385 parts by weight Resin solid content obtained by preparation of resin fine particle dispersion (2) 92 parts by weight Manganese-containing hematite (magnetic force 0 Am ² / g, center particle size 200 nm ) 50 parts by mass Magnetite (magnetic force 125 Am ² / g, center particle size 250 nm) 175 parts by mass Polyethylene wax (PW1000, manufactured by Toyo Petrolite) 90 parts by mass The above components were heated to 200 ° C. and melt-kneaded with a Banbury mixer. Thereafter, the mixture was cooled to room temperature and pulverized using a pulverizer (100AFG, manufactured by Hosokawa Micron Corporation) to obtain black toner particles of Example 7.
The obtained black toner particles were amorphous with a volume average particle size D50v of 8.5 μm, a volume average particle size distribution index GSDv of 1.28, a number average particle size distribution index GSDv of 1.30, and SF1 of 145.6. . Further, Mw of the toner was 166000, Mz was 460000, and Mz / Mw was 2.8.

Example 8
In Example 1, the same procedure as in Example 1 was performed except that the colorant dispersion (1) was changed to the colorant dispersion (9) and the colorant dispersion (5) was changed to the colorant dispersion (10). The black toner particles of Example 8 were obtained.
The obtained black toner particles had a volume average particle size D50v of 7.0 μm, a volume average particle size distribution index GSDv of 1.22, a number average particle size distribution index GSDp of 1.24 and SF1 of 133.5.
Further, Mw of the toner was 183000, Mz was 506000, and Mz / Mw was 2.8.

Example 9
Black toner particles of Example 9 were obtained in the same manner as in Example 1 except that the colorant dispersion (1) was changed to the colorant dispersion (9) in Example 1.
The obtained black toner particles had a volume average particle size D50v of 6.9 μm, a volume average particle size distribution index GSDv of 1.24, a number average particle size distribution index GSDp of 1.25 and SF1 of 132.7.
Further, Mw of the toner was 183000, Mz was 506000, and Mz / Mw was 2.8.

[Comparative Example 1]
Black toner particles of Comparative Example 1 were obtained in the same manner as in Example 1 except that the colorant dispersion (5) was omitted.
The resulting black toner particles had a volume average particle size D50v of 6.6 μm, a volume average particle size distribution index GSDv of 1.22, a number average particle size distribution index GSDp of 1.24 and SF1 of 130.5. Further, Mw of the toner was 180,000, Mz was 495,000, and Mz / Mw was 2.8.

[Comparative Example 2]
In Example 1, black toner particles of Comparative Example 2 were obtained in the same manner as Example 1 except that the colorant dispersion (1) was omitted.
The obtained black toner particles had a volume average particle size D50v of 6.5 μm, a volume average particle size distribution index GSDv of 1.32, a number average particle size distribution index GSDp of 1.41, and SF1 of 141.0. Further, Mw of the toner was 187000, Mz was 499000, and Mz / Mw was 2.7.

[Comparative Example 3]
Black toner particles of Comparative Example 3 were obtained in the same manner as in Example 1 except that the colorant dispersion (1) was changed to the colorant dispersion (11) in Example 1.
The obtained black toner particles had a volume average particle diameter D50v of 7.2 μm, a volume average particle size distribution index GSDv of 1.31, a number average particle size distribution index GSDp of 1.40 and SF1 of 147.0.
Further, Mw of the toner was 183000, Mz was 506000, and Mz / Mw was 2.8.

(Preparation of developer)
To 50 parts by mass of the toner particles of Examples 1 to 9 and Comparative Examples 1 to 3, 1.5 parts by mass of hydrophobic silica (TS720: manufactured by Cabot Corporation) was added, and the mixture was externally added using a sample mill. . These externally added toners are coated with 1% polymethylmethacrylate (molecular weight 50000, manufactured by Soken Chemical Co., Ltd.) with a ferrite carrier having an average particle size of 50 μm (35 μm: manufactured by Powdertech) so that the toner concentration is 20%. The developers of Examples 1 to 9 and Comparative Examples 1 to 3 were prepared by stirring and mixing for 5 minutes with a ball mill.

(Evaluation test)
The developers of Examples 1 to 9 and Comparative Examples 1 to 3 were applied to a modified Vivace 555 manufactured by Fuji Xerox Co., Ltd. in an environment of high temperature and high humidity (28 ° C., 90% RH), and the applied toner amount was 6.5 g. / M ² , the fixing speed was set to 180 mm / sec, the image was printed, and after running 10,000 sheets, the following evaluation was performed, and the results are shown in Tables 1 and 2.

(Evaluation)
1) Evaluation of density of fixed image The density of the fixed image after traveling 10,000 sheets was measured using X-rite 404 (manufactured by X-rite) and evaluated according to the following evaluation criteria.

<Evaluation criteria>
A: 1.40 or more / The density of the fixed image is sufficient.
Δ: 1.30 to 1.39 / Although the density of the fixed image is slightly insufficient, it can withstand practical use. X: Less than 1.30 / The density of the fixed image is insufficient.

2) Evaluation of fog and scattering The occurrence of fogging and scattering of the toner after traveling 10,000 sheets was visually confirmed and evaluated according to the following evaluation criteria.

<Evaluation criteria>
◯: Occurrence is not recognized.
(Triangle | delta): Although generation | occurrence | production is recognized slightly, it is a level which is satisfactory practically.
X: Occurrence is observed, and this is a practically problematic level.

3) Evaluation of defects on image The defects on the image of the fixed image after running the 10,000 sheets were visually confirmed and evaluated according to the following evaluation criteria.

<Evaluation criteria>
○: Level at which no defect occurs on the image.
(Triangle | delta): Although the defect | deletion has generate | occur | produced slightly on the image, it is a level which is satisfactory practically.
X: Defects are observed on the image, and this is a practically problematic level.

As is clear from Tables 1 and 2 above, the developers of Examples 1 to 6 are all satisfactory in the density of the fixed image, no fogging or scattering of toner, and no defects on the image. An image was formed. Further, with the developer of Example 7, the density of the fixed image was sufficient, but slight fogging and scattering of the toner were observed.
In the developer of Example 8, the density of the fixed image was sufficient, but slight fogging and scattering of the toner were observed.
On the other hand, since the toner of the developer of Comparative Example 1 excludes magnetite, ejection of toner was observed during running in the running test, and the test was stopped. In the developer toner of Comparative Example 2, the density of the fixed image was insufficient, and toner fogging and scattering occurred. In the developer toner of Comparative Example 3, the density of the fixed image was sufficient, but the toner was fogged and scattered, and black streaks were further generated.

Claims (4)

In the electrostatic image developing toner obtained by dispersing a colorant in a resin, the colorant has black compound fine particles having a magnetic force of 30 Am ² / kg or less and a particle size of 0.04 μm or more and 0.35 μm or less. A black toner for electrostatic charge development, comprising magnetic particles of more than 30 Am ² / kg and not more than 150 Am ² / kg. A resin fine particle dispersion in which at least 1 μm or less of resin fine particles are dispersed is mixed with a colorant dispersion, and the resin fine particles and the colorant are aggregated to form an aggregated particle dispersion. In a black toner for developing an electrostatic charge image that is heated to a temperature above a point to form a toner particle by fusing and coalescing, black compound fine particles having a magnetic force of 30 Am ² / kg or less and a particle size of 0.04 μm as the colorant When using magnetic particles having a magnetic force of more than 0.35 μm and a magnetic force of more than 30 Am ² / kg and not more than 150 Am ² / kg to form aggregated particles, the pH is controlled to 3.5 or less, and the Tg ( A method for producing a black toner for electrostatic charge development, comprising adding the magnetic particle dispersion in the range of glass transition point) to Tg-30 ° C. A developer for developing an electrostatic charge image, comprising using the black toner for electrostatic charge development according to claim 1 and a carrier. A step of forming an electrostatic latent image on the electrostatic latent image carrier, a step of developing the electrostatic latent image with a developer on the developer carrier to form a toner image, and the toner image on the transfer member The image forming method including a transferring step, a step of fixing a toner image on the transfer member, and a cleaning step of removing the toner remaining on the electrostatic latent image carrier, and the development according to claim 3 as the toner. An image forming method using an agent.