JP2008102434A - Yellow toner for electrostatic charge image development, magenta toner for electrostatic charge image development, developer for electrostatic charge image development, process cartridge and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide yellow toner for electrostatic charge image development and magenta toner for electrostatic charge image development giving an image having high color optical density and transparency, a developer for electrostatic charge image development including the yellow toner for electrostatic charge image development and the magenta toner for electrostatic charge image development, and to provide a process cartridge and an image forming apparatus using the developer for electrostatic charge image development. <P>SOLUTION: The yellow toner for electrostatic charge image development and the magenta toner for electrostatic charge image development include a binder resin, a colorant, a release agent and barium, wherein a content of the barium is ≥0.05 mass%. There are also provided the developer for electrostatic charge image development including the yellow toner for electrostatic charge image development and the magenta toner for electrostatic charge image development, and a process cartridge and an image forming apparatus using the developer for electrostatic charge image development. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrostatic charge developing yellow toner, an electrostatic charge developing magenta toner, an electrostatic charge developing yellow toner, or an electrostatic charge developing magenta toner used in an image forming apparatus that forms an image using an electrophotographic system. The present invention relates to a developer for developing electrostatic charge, a process cartridge using the developer for developing electrostatic charge, and an image forming apparatus.

  An electrophotographic method for visualizing image information through an electrostatic latent image is currently used in various fields (see, for example, Patent Documents 1 and 2), and the electrophotographic method is generally used in a charging / exposure process. Then, an electrostatic latent image is formed on the surface of the photoreceptor, and the electrostatic latent image is developed using an electrostatic charge image developer containing toner (hereinafter sometimes simply referred to as “developer”) in the development process. In the transfer process, the toner image is transferred onto a transfer material such as paper or sheet. In the fixing process, the toner image is fixed on the transfer material using heat, solvent, pressure, or the like. This is a method for obtaining a permanent image.

  In addition, digitization processing can be cited as a means to achieve high image quality, and the effect of digitization related to such image quality is that complex image processing can be performed at high speed. Can be controlled separately, and the reproducibility of text and photographic images is greatly improved compared to analog technology. In particular, for photographic images, gradation correction and color correction are possible, and this is advantageous over analog in terms of gradation characteristics, definition, sharpness, color reproduction, and graininess. Furthermore, it is necessary to faithfully form a latent image created by an optical system as an image output, and as a toner, an activity aimed at faithful reproduction is accelerated as the particle diameter is further reduced.

  On the other hand, in particular for color images, three or four color toners are superimposed to form an image. Color, density, and transparency are important as characteristics required for toner in this superposition. Of these three or four color toners, magenta and yellow toners are more likely to have defects in terms of visual color and transparency than other colors. In particular, yellow toners generally overlap color toners. When combined, this tendency is more prominent because it often comes to the top of the image. As a factor for controlling the transparency of the magenta and yellow toners, the pigment dispersibility in the toner influences. On the other hand, a method of reducing the pigment particle size is conceivable, and as a method of reducing the pigment particle size, a method of mechanically pulverizing the pigment after completion of synthesis / filtration / washing / drying is common.

  Further, for the purpose of avoiding deterioration of transparency, a composition in which a colorant is previously kneaded with a polyester resin and water is used to control the dispersed particle size in the toner (for example, see Patent Document 3), or the pigment is interfaced. A method of treating with an activator to improve pigment dispersion has been taken (see, for example, Patent Documents 4 and 5). Usually, it is added at the time of pulverization during the pigment production process as a method for treating the surfactant. The pulverization method includes a wet pulverization method and a dry pulverization method. The wet pulverization method is a method of pulverizing in a pigment or lubricant using a dispersion medium in water or in a solvent. In the dry pulverization method, the dried pigment is pulverized using a general pulverizer. The powder pigment is treated with a surfactant by a method such as spray drying. A wet method is preferable from the viewpoint of uniform treatment.

Furthermore, a method of incorporating fine particle barium sulfate in an organic pigment for the purpose of obtaining transparency has been proposed (for example, see Patent Document 6). In this process, barium sulfate is added in a process (soft milling) of mechanically reducing the primary particle diameter of the pigment by using an inorganic salt as an auxiliary agent for grinding the organic pigment.
US Pat. No. 2,297,691 U.S. Pat. No. 2,357,809 JP 2004-85997 A JP-A-3-267947 JP 2005-62517 A Japanese Patent Laid-Open No. 11-7159

  The present invention relates to an electrostatic charge developing yellow toner and an electrostatic charge developing magenta toner capable of obtaining an image having a high color density and transparency, and the electrostatic charge developing yellow toner or the electrostatic charge developing magenta toner containing the electrostatic charge developing magenta toner. It is an object of the present invention to provide a developer for a toner, a process cartridge using the developer for developing an electrostatic charge, and an image forming apparatus.

The above problems have been solved by the present invention described below.
That is, the present invention
<1> A yellow toner for electrostatic charge development, comprising a binder resin, a colorant, a release agent, and barium, wherein the barium content is 0.3% by mass or more.
<2> A resin particle dispersion in which binder resin particles are dispersed, a colorant dispersion in which a colorant obtained by synthesis in the presence of a barium compound is dispersed, and a release agent dispersion in which a release agent is dispersed are mixed. Then, one or more metal salts containing polyaluminum chloride are added thereto to form aggregated particles, and the aggregated particles are heated to fuse and coalesce and coalesce and coalesce. The yellow toner for electrostatic charge development according to <1>, wherein the yellow toner is manufactured through the processes described above.
<3> An electrostatic charge developing developer comprising the yellow toner for electrostatic charge developer according to <1> or <2>.

<4> A magenta toner for electrostatic charge development, comprising a binder resin, a colorant, a release agent, and barium, wherein the barium content is 0.3% by mass or more.
<5> A resin particle dispersion in which binder resin particles are dispersed, a colorant dispersion in which a colorant obtained by synthesis in the presence of a barium compound is dispersed, and a release agent dispersion in which a release agent is dispersed are mixed. Then, one or more metal salts containing polyaluminum chloride are added thereto to form aggregated particles, and the aggregated particles are heated to fuse and coalesce and coalesce and coalesce. The electrostatic charge developing magenta toner according to <4>, which is manufactured through
<6> An electrostatic charge developing developer comprising the magenta toner for electrostatic charge developer according to <4> or <5>.

<7> A developing device for developing the electrostatic latent image formed on the surface of the image carrier using the electrostatic charge developing developer according to <3> or <6> to form a toner image; At least one selected from the group consisting of the image carrier, a charging device for charging the surface of the image carrier, and a cleaning device for removing toner remaining on the surface of the image carrier. This is a featured process cartridge.

<8> An image carrier, a charging device for charging the surface of the image carrier, an exposure device for forming an electrostatic latent image on the charged surface of the image carrier, and the image carrier. The electrostatic latent image is developed using the electrostatic charge developing developer according to <3> or <6> to form a toner image, and the toner image is transferred to a transfer target. An image forming apparatus comprising: a transfer device; and a cleaning device for removing toner remaining on the surface of the image carrier.

  The present invention relates to an electrostatic charge developing yellow toner and an electrostatic charge developing magenta toner capable of obtaining an image having a high color density and transparency, and the electrostatic charge developing yellow toner or the electrostatic charge developing magenta toner containing the electrostatic charge developing magenta toner. Developer, a process cartridge using the developer for electrostatic charge development, and an image forming apparatus can be provided.

<Yellow toner for electrostatic charge development and magenta toner for electrostatic charge development>
The yellow toner for electrostatic charge development and the magenta toner for electrostatic charge development of the present invention (hereinafter sometimes referred to as “the toner of the present invention”) contain a binder resin, a colorant, a release agent, and barium. And the barium content is 0.3 mass% or more.

  It is presumed that an image having high transparency can be obtained by making the dispersibility of the colorant (pigment) in the toner uniform. As a method for obtaining high dispersibility of the colorant in the uniform toner, (1) the particle diameter of the colorant is made as small as possible. (2) Maintain a uniform dispersion of the colorant during toner production. Two methods are conceivable.

  As a method for reducing the particle size of the colorant as much as possible (1), there is generally a method in which the pulverization of the colorant is strengthened and the particle size is made close to the primary particle size. However, mechanically pulverized colorant particles have an increased surface area and tend to aggregate more, resulting in a larger apparent particle size distribution. Even if the center particle size is a small colorant, in reality, fine and apparently large particle sizes are mixed, and as a result, the transparency is not improved. On the other hand, as a method for obtaining high transparency, a method of making the particle size of the colorant uniform in the synthesis stage in order to reduce the particle size of the colorant and maintain it or to redisperse the aggregation with less force Is mentioned. Originally, the particle size (primary particle size) of the colorant particles tends to be determined by crystal growth during synthesis. By controlling the crystal growth, it is possible to obtain small-sized colorant particles. As a method for controlling this crystal growth, it is conceivable to arrange inclusions at the interface between crystals during crystal growth. That is, by arranging inclusions at the interface between the colorants that grow during the synthesis of the colorant, crystal growth can be suppressed, and at the time of pulverization, inclusions at the crystal interface serve as a pulverization aid to facilitate pulverization.

  In addition, as described in (2) above, it is necessary to maintain the dispersion state of the colorant particles during the production of the toner. However, if a fine colorant is simply used, a certain degree of transparency improvement effect can be obtained, but the colorant in the toner. Is not sufficient for the dispersion of For example, in the kneading and pulverizing method, there is a limit to uniform pigment dispersion even if the kneading conditions are strengthened. In addition, in a toner containing a release agent, if the kneading conditions are strengthened, the release agent is specifically dispersed, so that the release agent cannot be dispersed or the result is greatly deviated from the desired composition. There is. Further, in the method for producing toner in water, there is little aggregation between the colorant particles in the emulsion polymerization aggregation method having a toner aggregation step (a step of collecting an emulsion such as a resin, a release agent, and a colorant using a flocculant). Even if the colorant particles have a small particle size, the result is the same as when large particles are used. This cannot be improved by simply increasing or decreasing the amount of the flocculant. If the coagulant is reduced, the dispersibility is improved, but the colorant particles are likely to remain without agglomeration and the coloring power of the toner may be reduced. On the other hand, when the coagulant is increased, the colorant agglomerates. Since it is easy, the pigment dispersion in the toner may be non-uniform.

As a result of intensive studies, the present inventors have (1) reduced the particle size of the colorant as much as described above, and (2) kept the colorant dispersed during toner production, thereby dispersing the colorant in the toner. In order to improve the property, the inventors have found that the addition of a barium compound to the toner is performed. Further, the barium compound is added when the colorant is synthesized, that is, in the present invention, it is particularly preferable to use the colorant obtained by synthesis in the presence of the barium compound.
This is because barium compounds such as barium sulfate are excellent in heat resistance and hardly soluble in acids and alkalis. That is, the barium compound is present at the interface between the colorant particles in a stable state even in an acid / alkali state in the colorant synthesis. Moreover, it can exist stably also with respect to the temperature at the time of drying. Furthermore, when the toner is manufactured, for example, even when polyaluminum chloride is used as the aggregating agent, the colorant particles contain barium, so that the coagulability does not contain barium compared to the resin or the release agent. Can be relaxed compared to As a result, a toner having high colorant dispersibility can be produced while suppressing the cohesiveness of the colorant. This is because barium is electrically positive and consequently suppresses the cohesiveness between the colorants, and at the same time, suppresses excessive cohesiveness of the colorant particles by repelling the metal ions of the coagulant. It is thought to have come from. In other words, by adding a barium compound to the toner, especially by adding the barium compound when synthesizing the colorant, both the effects of maintaining a small diameter colorant and dispersibility of the colorant at the time of toner production are exhibited. Can do.

  Further, the above-described effects obtained by setting the barium content to 0.3% by mass or more are effective with yellow toner and magenta toner, and are remarkably exhibited with yellow toner. In general, when color toners are overlapped, yellow toner often comes to the top of the image, and when yellow toner has low transparency, toner that is below yellow toner (usually magenta, cyan, etc.) This is because the color of the color changes and the color reproducibility is hindered. The yellow colorant (pigment) generally has a large tendency to aggregate during the production of the toner, and the yellow toner of the present invention that can solve this problem is particularly preferable.

(Barium compound)
Examples of the barium compound include barium sulfate, barium nitrate, barium iodide, barium fluoride, barium carbonate, barium chloride, barium bromide and other barium salts, barium oxide, barium peroxide and other oxides, dimethoxybarium, diethoxy Alkoxides such as barium, di-i-propoxybarium, di-n-propoxybarium, di-i-butoxybarium, di-n-butoxybarium and the like can be used, and a toner having a small diameter and a uniform color can be obtained. Barium sulfate is particularly preferable in that both effects of maintaining the colorant dispersion uniformity can be remarkably exhibited.

In the toner of the present invention, by adding the barium compound, it is essential that the barium content is 0.3% by mass or more, preferably 0.6% by mass or more, and 0.8% by mass. More preferably. When the barium content is less than 0.3% by mass, the colorant tends to agglomerate, and the effect of maintaining the dispersibility of the colorant during toner production cannot be obtained. In view of fixing temperature, the barium content is preferably 2.0% by mass or less. This is because barium sulfate tends to repel metal ions as described above, and when added excessively, the pigment tends to remain outside the aggregated particles during aggregation, resulting in a decrease in the amount of colorant added to the toner. May end up.
In the toner of the present invention, the barium content refers to the amount of barium contained in the toner, and does not include so-called externally added barium. The barium content can be measured using fluorescent X-rays (LAB CENTER XRF-1500: manufactured by Shimadzu Corporation). Specifically, 200 mg of a sample was subjected to compression processing on pellets using a compression molding machine having a diameter of 13 mm, and measurement was performed. The NET intensity at this time was determined as an actual barium amount using a barium calibration curve.

(Coloring agent)
In the toner of the present invention, the following colorant is synthesized and used in the presence of a barium compound.
When the toner of the present invention is a yellow toner for electrostatic charge developer (hereinafter sometimes referred to as “the yellow toner of the present invention”), the colorant used is preferably an azo pigment, and an azo pigment having a phenyl group. A pigment is more preferable, and particularly preferable is C.I. represented by a compound represented by the following formula (1). I. Pigment Yellow 74, C.I. I. Pigment Yellow 1, 2, 3, 5, 6, 49, 65, 73, 75, 97, 98, 111, 116, 130 and the like; C represented by the compound represented by the following formula (2) . I. Pigment Yellow 154, C.I. I. Benzimidazolone pigments such as Pigment Yellow 120, 151, 175, 180, 181 and 194; C.I. represented by the compound represented by the following formula (3) I. Pigment Yellow 93, C.I. I. Pigment Yellow 94, 95, 128, 166, etc. disazo condensation pigments; I. Pigment Yellow 12, 13, 14, 17, 55, 63, 81, 83, 87, 90, 106, 113, 114, 121, 124, 126, 127, 136, 152, 170, 171, 172, 174, 176, Disazo pigments such as 188; and the like.

  This is effective when the colorant used in the yellow toner of the present invention is an azo pigment. This is because azo pigments are known to undergo crystal growth after synthesis, but when synthesized in the presence of a barium compound, barium is involved in the azo bond portion to suppress crystal growth and simultaneously remain at the crystal interface. In order to alleviate the adhesion between the crystals, the resulting crystal growth is suppressed and the primary particles are considered to be maintained in a small diameter. In addition, when a toner is prepared using this pigment, particularly when the emulsion aggregation method is used, it is considered that the charge of barium relaxes the aggregation during toner aggregation and improves the dispersibility in the toner, and the effect of the present invention is obtained. It is thought that.

  When the toner of the present invention is the magenta toner for electrostatic charge developer of the present invention (hereinafter sometimes referred to as “magenta toner of the present invention”), the colorant used is represented by the following formula (4). C. typified by compounds. I. Pigment Red 146, C.I. I. Pigment Red 2, 5, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 21, 22, 23, 31, 32, 95, 112, 114, 119, 136, Β-naphthol such as 147, 148, 150, 164, 170, 184, 187, 188, 210, 212, 213, 222, 223, 238, 245, 253, 256, 258, 261, 266, 267, 268, 269 Pigments represented by the following formula (5): C.I. I. Pigment Red 57: 1, others include C.I. I. Pigment Red 18: 1, 48: 2, 48: 3, 48: 4, 48: 5, 50: 1, 51, 52: 1, 52: 2, 53: 1, 53: 2, 53: 3, 58: Azo lake pigments such as 2, 58: 4, 64: 1, 68, and 200; C.I. represented by the compound represented by the following formula (6). I. Pigment Red 209, C.I. I. Pigment Red 122, 192, 202, 207, C.I. I. Quinacridone pigments such as Pigment Violet 19; I. Pigment Red 37, 38, 41, 111, C.I. I. Pigment Orange 13, 15, 16, 34, 44, and the like.

  The colorant used in the magenta toner of the present invention exhibits the same effect in the azo system as in the yellow pigment.

  The content of the colorant in the toner of the present invention (yellow toner for electrostatic charge development and magenta toner for electrostatic charge development) is preferably 3 to 15% by mass, and more preferably 4 to 10% by mass. When the content of the colorant exceeds 15% by mass, the pigment particles function as fillers, and as a result, the toner tends to be in a state where the viscosity is high with respect to heat. As a result, not only the transparency of the toner decreases, but also the fixing temperature may be increased. If it is less than 3% by mass, transparency may be obtained, but good color developability may not be obtained.

(Binder resin)
The binder resin used in the toner of the present invention is not particularly limited, and a known resin material can be used. For example, styrenes such as styrene, parachlorostyrene, α-methylstyrene, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate , Esters having a vinyl group such as 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 Polymers such as vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; polyolefins such as ethylene, propylene and butadiene; Copolymers obtained by combining them or a mixture thereof can be mentioned, and furthermore, epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, etc., non-vinyl condensation resins, or these and the vinyl Examples thereof include a mixture with a resin and a graft polymer obtained when a vinyl monomer is polymerized in the presence of these.

  When the resin is prepared using a vinyl monomer, a resin particle dispersion can be prepared by carrying out emulsion polymerization using an ionic surfactant or the like. If it is oily and dissolves in a solvent with relatively low solubility in water, 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. Thereafter, the resin particle dispersion can be prepared by evaporating the solvent by heating or reducing the pressure.

(Release agent)
The release agent used in the toner of the present invention is preferably a substance having a main maximum peak measured in accordance with ASTM D3418-8 in the range of 50 to 140 ° C. If the main maximum peak is less than 50 ° C., offset may easily occur during fixing. On the other hand, if the temperature exceeds 140 ° C., the fixing temperature becomes high, and the glossiness may be impaired due to insufficient smoothness of the image surface. For the measurement of the main maximum peak, for example, DSC-7 manufactured by Perkin Elmer can be used. The temperature correction of the detection part of this apparatus uses the melting point 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.

The viscosity η1 at 160 ° C. of the release agent is preferably in the range of 20 to 600 cps. If the viscosity η1 is less than 20 cps, hot offset may be likely to occur, and if it is greater than 600 cps, cold offset may occur during fixing.
Furthermore, the ratio (η2 / η1) of the viscosity η1 at 160 ° C. and the viscosity η2 at 200 ° C. of the release agent is preferably in the range of 0.5 to 0.7. If η2 / η1 is smaller than 0.5, the bleed amount at a low temperature is small and a cold offset may occur. On the other hand, if the ratio is larger than 0.7, the amount of bleeding at the time of fixing at a high temperature increases, which may cause a wax offset and may cause a problem in peeling stability.

Specific examples of the release agent include low molecular weight polyolefins such as polyethylene, polypropylene and polybutene, silicones having a softening point by heating, oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide and the like. Fatty acid amides, carnauba wax, rice wax, candelilla wax, plant waxes such as tree wax and jojoba oil, animal waxes such as beeswax, montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, fisher Minerals such as Tropsch wax, petroleum-based waxes, and modified products thereof can be used.
These release agents 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. A release agent dispersion liquid containing particles of release agent having a particle diameter of 1 μm or less can be produced.

  The content of the release agent in the toner of the present invention is preferably 3 to 20% by mass, and more preferably 6 to 12% by mass. If the content of the release agent is less than 3% by mass, the original release function may be insufficiently offset, and if it exceeds 20% by mass, the separation between the fixing member and the toner image surface may occur during fixing. Since the mold component component is excessively interposed, a minute slip may occur. As a result, image quality defects such as image flow may occur.

  In the toner of the present invention, in addition to the binder resin, the colorant, the mold release agent, and the barium compound, other components (particles) such as an internal additive, a charge control agent, and inorganic particles are added according to the purpose. It is possible to add.

  Examples of internal additives include metals such as ferrite, magnetite, reduced iron, cobalt, manganese, and nickel, alloys, and magnetic materials such as compounds containing these metals, and inhibit charging properties as toner characteristics. A small amount can be used.

  The charge control agent is not particularly limited, but a colorless or light-colored agent can be preferably used. Examples include quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments. From the viewpoint of controlling strength and reducing wastewater contamination, a material that is difficult to dissolve in water is preferred.

  In addition, inorganic particles can be added in a wet manner to the toner of the present invention in order to stabilize the chargeability. As the inorganic particles to be added, any of those usually used as external additives on the toner surface, such as silica, alumina, titania, calcium carbonate, magnesium carbonate, and tricalcium phosphate, can be used. It is preferable to use by dispersing with a molecular acid or a polymer base.

  The content of the other components may be a level that does not hinder the object of the present invention, is generally a very small amount, specifically in the range of 0.01 to 5% by mass, preferably It is in the range of 0.5 to 2% by mass.

  The toner of the present invention can be produced by any production method such as a kneading and pulverization method, a suspension polymerization method, a dissolution suspension method, and an emulsion aggregation coalescence method as long as it is a production method that can contain barium. From the viewpoint of the uniform pigment dispersibility, the degree of freedom in designing the amount of the release agent, the toner particle size, and the particle size distribution, it is preferable to produce by an emulsion aggregation method. The emulsion aggregation method includes a resin particle dispersion in which binder resin particles are dispersed, a colorant dispersion in which a colorant obtained by synthesis in the presence of a barium compound is dispersed, and a release agent dispersion in which a release agent is dispersed. And agglomerated particles forming step of forming aggregated particles by adding one or more metal salts containing polyaluminum chloride thereto, and heating and aggregating and aggregating the aggregated particles. It is the method of manufacturing through one process.

  The toner of the present invention may have a core / shell structure. In this case, the production method by the emulsion aggregation method is obtained by synthesizing a resin particle dispersion in which binder resin particles are dispersed in the presence of a barium compound. The obtained colorant dispersion in which the colorant is dispersed and the release agent dispersion in which the release agent is dispersed are mixed, to which one or more metal salts containing polyaluminum chloride are added, and aggregated particles ( An agglomerated particle forming step (first agglomerated particle forming step) for forming a core agglomerated particle; and a second layer for obtaining a core / shell agglomerated particle by forming a shell layer containing a second resin particle on the surface of the core agglomerated particle. The aggregated particle forming step, and the core / shell aggregated particles are heated and fused and united for fusing and uniting. Hereinafter, a production method when the toner of the present invention has a core / shell structure will be described.

  In the first aggregated particle forming step, first, a resin particle dispersion, a colorant dispersion, and a release agent dispersion are prepared. The resin particle dispersion is prepared by dispersing resin particles prepared by emulsion polymerization or the like in a solvent using an ionic surfactant.

  The colorant dispersion is colored by first dissolving an azo component in an acid, separately dissolving a barium compound such as barium sulfate in a coupler component whose pH is adjusted to the alkali side, and adding the azo component dropwise. An agent is synthesized and prepared by dispersing the synthesized colorant in a solvent using an ionic surfactant opposite to the ionic surfactant used to prepare the resin particle dispersion. The particle size (center particle size) of the colorant after dispersion is preferably 50 to 250 nm, and more preferably 80 to 200 nm. When the particle size of the colorant is less than 50 nm, the transparency is good, but color developability may not be obtained, and uniform stabilization of the dispersed state may be difficult. However, transparency and pigment dispersibility in the toner may deteriorate. The particle size of the colorant was measured using a laser diffraction particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.).

  Furthermore, the release agent dispersion is a homogenizer that disperses the release agent in water together with a polymer electrolyte such as an ionic surfactant, a polymer acid, or a polymer base, and heats it above the melting point and applies strong shear. Or by granulating with a pressure discharge type disperser.

Next, the resin particle dispersion, the colorant dispersion, and the release agent dispersion are mixed, and the resin particles, the colorant, and the release agent are hetero-aggregated, and the resin particles have a diameter that is approximately close to a desired toner diameter. Agglomerated particles (core agglomerated particles) including the colorant and the release agent are formed (first aggregated particle forming step).
In the second aggregated particle forming step, the second resin particles are adhered to the surface of the core aggregated particles obtained in the first aggregated particle forming step by using a resin particle dispersion containing the second resin particles. By forming a coating layer (shell layer) having a desired thickness, aggregated particles (core / shell aggregated particles) having a core / shell structure in which a shell layer is formed on the surface of the core aggregated particles are obtained. In addition, the 2nd resin particle used in this case may be the same as the 1st resin particle, and may differ.

  The particle diameters of the binder resin particles, the second resin particles, the colorant particles, and the release agent particles used in the first and second aggregated particle forming steps may be set to a desired toner diameter and particle size distribution. In order to facilitate the adjustment to the value, it is preferably 1 μm or less, and more preferably in the range of 100 to 300 nm.

  In the first aggregated particle forming step, the balance of the amounts of the two polar ionic surfactants (dispersants) contained in the resin particle dispersion or the colorant dispersion can be shifted in advance. For example, an inorganic metal salt such as calcium nitrate or a polymer of an inorganic metal salt such as polyaluminum chloride is ionically neutralized and heated below the glass transition temperature of the binder resin particles to form core agglomerated particles. Can be produced.

  In such a case, in the second agglomerated particle forming step, the resin particle dispersion treated with the polarity and the amount of the dispersing agent so as to compensate for the deviation of the balance between the two polar dispersing agents as described above, The core / shell aggregated particles are added to the solution containing the core aggregated particles and further heated slightly below the glass transition temperature of the core aggregated particles or the second resin particles used in the second aggregation step as necessary. Can be produced. In addition, the 1st and 2nd aggregated particle formation process may be repeatedly performed in steps divided into a plurality of times.

Next, in the fusion / unification step, the core / shell aggregated particles obtained through the second aggregated particle forming step are combined with the binder resin particles contained in the core / shell aggregated particles or the second aggregated particles. A toner is obtained by heating above the glass transition temperature of the resin particles 2 (if the resin type is two or more, the glass transition temperature of the resin having the highest glass point transition temperature), fusing and coalescing. After completion of the fusion / unification process, the toner formed in the solution is dried through a known washing process, solid-liquid separation process, and drying process to obtain a toner.
In addition, it is preferable that the washing | cleaning process performs substitution washing | cleaning by ion-exchange water fully from a charging point. The solid-liquid separation step is not particularly limited, but suction filtration, pressure filtration, and the like are preferably used from the viewpoint of productivity. Further, although the drying process is not particularly limited, freeze drying, flash jet drying, fluidized drying, vibration fluidized drying and the like are preferably used from the viewpoint of productivity.

<Developer for electrostatic charge development>
The developer for developing an electrostatic charge of the present invention is not particularly limited except that it contains the yellow toner of the present invention or the magenta toner of the present invention, and can have an appropriate component composition depending on the purpose. The electrostatic image developer of the present invention becomes a one-component electrostatic image developer when the toner of the present invention is used alone, and becomes a two-component electrostatic image developer when used in combination with a carrier. .

(Career)
[Carrier core]
The carrier core material preferably has a volume electrical resistance (25 ° C.) of 1 × 10 ^7.5 to 1 × 10 ^9.5 Ω · cm. If this electrical resistance is less than 1 × 10 ^7.5 Ω · cm, there is a possibility that when the toner concentration in the developer is reduced by repeated copying, charges are injected into the carrier and the carrier itself is developed. is there. On the other hand, if the electric resistance is greater than 1 × 10 ^9.5 Ω · cm, the image quality such as the outstanding edge effect and pseudo contour may be adversely affected.
The carrier core material is not particularly limited as long as the above conditions are satisfied. For example, magnetic metals such as iron, steel, nickel and cobalt, alloys of these with manganese, chromium and rare earths, and magnetic materials such as ferrite and magnetite. An oxide etc. are mentioned. Among these, ferrite, particularly an alloy with manganese, lithium, strontium, magnesium or the like is preferably used from the viewpoint of core surface properties and core material resistance.

[Carrier coating layer]
In the carrier used in the present invention, examples of the coating resin for forming the carrier coating layer that covers the carrier core material include thermoplastic resin particles and thermosetting resin particles. Among these, thermosetting resins are preferable from the viewpoint of relatively easily increasing the hardness, and resin particles made of nitrogen-containing resin containing N atoms are preferable from the viewpoint of imparting negative chargeability to the toner. In addition, these resin particles may be used individually by 1 type, and may use 2 or more types together. The average particle size of the resin particles is preferably about 0.1 to 2 μm, more preferably 0.2 to 1 μm. When the average particle diameter of the resin particles is less than 0.1 μm, the dispersibility of the resin particles in the coating film may be deteriorated. When the average particle diameter exceeds 2 μm, the resin particles may easily fall off from the coating film. is there.

  The conductive particles used in combination include metal particles such as gold, silver and copper, carbon black particles, semiconductive oxide particles such as titanium oxide and zinc oxide, titanium oxide, zinc oxide, barium sulfate and aluminum borate. And particles having the surface of potassium titanate powder or the like covered with tin oxide, carbon black, metal or the like. These may be used individually by 1 type and may use 2 or more types together. Among these, carbon black particles are preferable from the viewpoints of production stability, cost, conductivity, and the like. The type of carbon black is not particularly limited, but carbon black having a DBP oil absorption of about 50 to 250 ml / 100 g is preferable because of excellent production stability.

  The carrier coating layer may contain a fluorine-based resin, and the fluorine-based resin can be appropriately selected according to the purpose, but polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrimethyl. Examples thereof include known resins such as fluororesins such as fluoroethylene. These may be used individually by 1 type and may use 2 or more types together.

  Furthermore, the carrier coating layer is preferably formed by dispersing at least resin particles and / or conductive particles. When the resin particles are dispersed in the carrier coating layer, the carrier particles are uniformly dispersed in the thickness direction and the tangential direction of the carrier surface. Surface formation similar to that at the time of use can be maintained, and good charge imparting ability for the toner can be maintained over a long period of time. Further, when conductive particles are dispersed in the carrier coating layer, the carrier is used for a long time because the conductive particles are uniformly dispersed in the thickness direction and the tangential direction of the carrier surface. Even when the surface is worn, it is possible to always maintain the same surface formation as when not in use, and to prevent carrier deterioration for a long time. In addition, when the resin particle and electroconductive particle are disperse | distributed to a carrier coating layer, the above-mentioned effect can be show | played simultaneously.

Examples of the carrier manufacturing method include a method of forming a carrier coating layer with a coating resin on the surface of the carrier core material, specifically, an immersion method in which the carrier core material is immersed in a carrier coating layer forming liquid containing the coating resin, Spray method of spraying carrier coating layer forming liquid on the surface of carrier core material, kneader coater method of mixing carrier coating layer forming liquid in a state where carrier core material is suspended by flowing air, and removing solvent It is done. Among these, the kneader coater method is preferable in the present invention.
Further, the solvent used in the carrier coating layer forming liquid is not particularly limited as long as it can dissolve only the coating resin, and can be selected from known solvents per se, for example, Aromatic hydrocarbons such as toluene and xylene, ketones such as acetone and methyl ethyl ketone, and ethers such as tetrahydrofuran and dioxane.

<Image forming apparatus and process cartridge>
Next, the image forming apparatus and process cartridge of the present invention using the above-described developer for developing electrostatic charge of the present invention will be described.
The process cartridge of the present invention includes a developing device for developing a latent electrostatic image formed on the surface of an image carrier using the electrostatic charge developing developer of the present invention to form a toner image, and the image carrier. At least one selected from the group consisting of a charging device for charging the surface of the image carrier and a cleaning device for removing toner remaining on the surface of the image carrier. Thus, it is removable from the image forming apparatus.
The image forming apparatus of the present invention includes an image carrier, a charging device for charging the surface of the image carrier, an exposure device for forming an electrostatic latent image on the charged surface of the image carrier, The electrostatic latent image formed on the image carrier is developed using the electrostatic charge developing developer of the present invention to form a toner image, and the toner image is transferred to the transfer target. A transfer device; and a cleaning device for removing toner remaining on the surface of the image carrier. A portion including the developing device, the charging device, and the cleaning device is disposed on the image forming apparatus main body. A removable cartridge structure (the process cartridge of the present invention described above) may be used.

  An example of the image forming apparatus of the present invention is shown in FIG. 1 below, but is not limited to this. Only the main part shown in the figure will be described, and the description of other parts will be omitted.

  FIG. 1 is a schematic diagram showing a quadruple tandem full-color image forming apparatus. The image forming apparatus shown in FIG. 1 is a first to first electrophotographic method that outputs yellow (Y), magenta (M), cyan (C), and black (K) images based on color-separated image data. Fourth image forming stations 10Y, 10M, 10C, and 10K (image forming means) are provided. These image forming stations (hereinafter simply referred to as stations) 10Y, 10M, 10C, and 10K are juxtaposed at a predetermined distance from each other. The stations 10Y, 10M, 10C, and 10K may be process cartridges that can be attached to and detached from the main body of the image forming apparatus.

  Above each station 10Y, 10M, 10C, 10K, an intermediate transfer belt 20 as an intermediate transfer member is extended through each station. The intermediate transfer belt 20 is wound and stretched around a driving roller 22 and a support roller 24 that are in contact with the inner surface of the intermediate transfer belt 20 that are spaced apart from each other in the lateral direction, and travels from the first station 10Y to the fourth station 10K. It is designed to run endlessly in the direction. The support roller 24 is urged away from the drive roller 22 by a spring or the like (not shown), and a predetermined tension is applied to the intermediate transfer belt 20 wound between the two. Further, an intermediate transfer member cleaning device 30 is provided on the side of the image carrier of the intermediate transfer belt 20 so as to face the driving roller 22.

  Since the first to fourth stations 10Y, 10M, 10C, and 10K described above have substantially the same configuration, the first station that forms a yellow image disposed upstream in the traveling direction of the intermediate transfer belt here. 10Y will be described as a representative. The same reference numerals with magenta (M), cyan (C), and black (K) are attached to the same parts as those of the first station 10Y instead of yellow (Y). Description of the stations 10M, 10C, and 10K is omitted.

The first station 10Y includes a photoreceptor 1Y that functions as an image holding member. Around the photoconductor 1Y, a charging roller (charging device) 2Y for charging the surface of the photoconductor 1Y to a predetermined potential, and the charged surface is exposed by a laser beam 3Y based on the color-separated image signal to electrostatically An exposure device 3 for forming a latent image, a developing device 4Y for supplying a charged toner (developer) to the electrostatic latent image to develop the electrostatic latent image, and a developed toner image (developer image) for the intermediate transfer belt 20 A primary transfer roller 5Y (transfer device) for transferring up and a photoconductor cleaning device 6Y for removing toner remaining on the surface of the photoconductor 1Y after the primary transfer are arranged in this order.
The primary transfer roller 5Y is disposed inside the intermediate transfer belt 20, and is provided at a position facing the photoreceptor 1Y. Further, a bias power source (not shown) for applying a primary transfer bias is connected to each of the primary transfer rollers 5Y, 5M, 5C, and 5K. Each bias power source varies the transfer bias applied to each primary transfer roller under the control of a control unit (control means) (not shown).

Hereinafter, an operation of forming a yellow image in the first station 10Y will be described.
The photoreceptor 1Y is formed by laminating a photosensitive layer on a conductive substrate. This photosensitive layer usually has a high resistance, but has a property that the specific resistance of the portion irradiated with the laser beam changes when irradiated with the laser beam 3Y. Therefore, a laser beam 3Y is output to the surface of the charged photoreceptor 1Y via the exposure device 3 in accordance with yellow image data sent from a control unit (not shown). The laser beam 3Y is applied to the photosensitive layer on the surface of the photoreceptor 1Y, whereby an electrostatic latent image of a yellow print pattern is formed on the surface of the photoreceptor 1Y.

The electrostatic latent image is an image formed on the surface of the photoreceptor 1Y by charging, and the specific resistance of the irradiated portion of the photosensitive layer is lowered by the laser beam 3Y, and the charged charge on the surface of the photoreceptor 1Y is reduced. On the other hand, it is a so-called negative latent image formed by the charge remaining in the portion not irradiated with the laser beam 3Y.
The electrostatic latent image formed on the photoreceptor 1Y in this way is rotated to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic latent image on the photoreceptor 1Y is converted into a visible image (toner image) by the developing device 4Y.

  In the developing device 4Y, the electrostatic charge developing developer of the present invention containing the yellow toner of the present invention described above is accommodated. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y, and has a charge of the same polarity (negative polarity) as the charged charge on the photoreceptor 1Y. As the surface of the photoreceptor 1Y passes through the developing device 4Y, yellow toner is electrostatically attached only to the latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. . The photoreceptor 1Y on which the yellow toner image is formed continues to run at a predetermined speed, and the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

  When the yellow toner image on the photoreceptor 1Y is conveyed to the primary transfer, a predetermined primary transfer bias is applied to the primary transfer roller 5Y, and the electrostatic force directed from the photoreceptor 1Y to the primary transfer roller 5Y generates a toner image. The toner image on the photoreceptor 1 </ b> Y is transferred onto the intermediate transfer belt 20. The transfer bias applied at this time is a (+) polarity opposite to the polarity (−) of the toner. For example, in the first station 10Y, a constant current is controlled to about +10 μA by a control unit (not shown). .

The primary transfer bias applied to the primary transfer rollers 5M, 5C, and 5K after the second station 10M is similarly controlled.
In this way, the intermediate transfer belt 20 to which the yellow toner image is transferred at the first station 10Y is sequentially conveyed through the second to fourth stations 10M, 10C, and 10K, and the toner images of the respective colors are similarly superimposed and transferred in a multiple manner. The Note that the developer for electrostatic charge development of the present invention containing the magenta toner of the present invention described above is accommodated in the developing device 4M.

  The intermediate transfer belt 20 on which the toner images of all colors are transferred in multiple passes through the first to fourth stations, the intermediate transfer belt 20, the support roller 24 in contact with the inner surface of the intermediate transfer belt 20, and the image transfer surface side of the intermediate transfer belt 20. The secondary transfer roller (secondary transfer unit) 26 arranged to the secondary transfer portion is provided. On the other hand, a recording paper (transfer material) P is fed at a predetermined timing between the secondary transfer roller 26 and the intermediate transfer belt 20 via a supply mechanism, and a predetermined secondary transfer bias is applied to the support roller 24. The The transfer bias applied at this time is a (−) polarity that is the same polarity as the polarity (−) of the toner, and an electrostatic force from the intermediate transfer belt 20 toward the recording paper P is applied to the toner image, so The toner image is transferred onto the recording paper P. The secondary transfer bias at this time is determined according to the resistance detected by a resistance detection means (not shown) for detecting the resistance of the secondary transfer portion, and is controlled by a constant voltage.

  Thereafter, the recording paper P is fed into the fixing device 28, the toner image is heated, and the color-superposed toner image is melted and permanently fixed on the recording paper P. The recording paper P on which the color image has been fixed is carried out toward the discharge unit, and a series of color image forming operations is completed.

  The transfer target in the present invention is not particularly limited as long as it is a medium for transferring a toner image formed on the electrophotographic photosensitive member 1. For example, when transferring directly from the electrophotographic photosensitive member 1 to paper or the like, paper or the like is a transfer target, and when an intermediate transfer member is used, the intermediate transfer member is a transfer target.

  Since the image obtained using the image forming apparatus and the process cartridge of the present invention contains the yellow toner of the present invention or the magenta toner of the present invention, an image having a high color density and transparency can be obtained.

Examples of the present invention will be described below, but the present invention is not limited to these examples. In the following description, “parts” means “parts by mass” and “%” means “% by mass” unless otherwise specified.
<Preparation of yellow pigment>
(Preparation of CI Pigment Yellow 74 Pigment 1)
Pigment synthesis: C.I. I. 33.6 parts of 2-methoxy-4-nitroaniline, which is a raw material component of Pigment Yellow 74, is added to 200 parts of a 4N hydrochloric acid aqueous solution, dispersed at room temperature for 2 hours, and then cooled to 0 ° C. or lower with ice. Next, 48.3 parts of 30% aqueous sodium nitrite solution was added thereto for diazotization, excess nitrite was decomposed with sulfamic acid, diatomaceous earth was added and insolubles were removed by filtration, and a clear pale yellow A diazonium salt solution was obtained.
On the other hand, 41.4 parts of 2-methoxyacetoacetanilide was dissolved in 305 parts of 2N aqueous sodium hydroxide solution, then cooled and added with 320 parts of 2N aqueous acetic acid solution to precipitate 2-methoxyacetoacetanilide, Further, 81.6 parts of sodium acetate trihydrate was added to adjust the temperature to 20 ° C. to obtain 748 parts of a coupling component aqueous solution.

  To 270 parts of the coupling component aqueous solution, 220 parts of the diazonium salt solution, 10 parts of rosin resin powder and 10 parts of barium sulfate (manufactured by Wako Pure Chemical Industries, Ltd.) were added dropwise at 20 ° C. over 2 hours. The coupling reaction was completed by stirring for 2 hours or more. Further, the obtained azo pigment slurry was heated to 90 ° C. and aged at 90 ° C. for 30 minutes, whereby a yellow pigment was obtained. This is filtered and washed with water to obtain a water-containing press cake. The press cake was dried at 90 ° C. for 20 hours, and a clear C.I. I. 107.8 parts of Pigment Yellow 74 Pigment 1 were obtained.

(Preparation of CI Pigment Yellow 74 Pigment 2)
C. I. In the production of Pigment Yellow 74 Pigment 1, C.I. I. Pigment Yellow 74 Pigment 1 was prepared in the same manner as in C.I. I. Pigment Yellow 74 pigment 2 was obtained.

(Preparation of CI Pigment Yellow 74 Pigment 3)
C. I. Pigment Yellow 74 Pigment 1 was prepared except that the amount of barium sulfate added was replaced with 20 parts. I. Pigment Yellow 74 Pigment 1 was prepared in the same manner as in C.I. I. Pigment Yellow 74 pigment 3 was obtained.

(Preparation of CI Pigment Yellow 74 Pigment 4)
C. I. Pigment Yellow 74 Pigment 1 was prepared except that barium sulfate was replaced with barium nitrate. I. Pigment Yellow 74 Pigment 1 was prepared in the same manner as in C.I. I. Pigment Yellow 74 pigment 4 was obtained.

(Preparation of CI Pigment Yellow 127 Pigment 1)
A mixture of 50.0 parts of 3,3′-dichlorobenzidine and 1.0 part of 3,3′-dimethoxybenzidine was tetrazotized by a known method to prepare a tetrazonium salt. A mixed coupling solution consisting of 55.8 parts of acetoacetoxydide, 1.5 parts of acetoacetanilide-p-sulfonic acid and 21.3 parts of acetoaceto-o-methoxyanilide was prepared.
After adding 270 parts of the tetrazonium salt solution, 10 parts of rosin resin powder and 10 parts of barium sulfate (manufactured by Wako Pure Chemical Industries, Ltd.) to 300 parts of the mixed coupling solution at 20 ° C. over 2 hours, The coupling reaction was completed by stirring for 2 hours or more. Further, the obtained azo pigment slurry was heated to 90 ° C. and aged at 90 ° C. for 30 minutes, whereby a yellow pigment was obtained. This is filtered and washed with water to obtain a water-containing press cake. The presscake was dried at 90 ° C. for 20 hours and 140 parts of C.I. I. Pigment Yellow 127 Pigment 1 was obtained.

(Preparation of CI Pigment Yellow 127 Pigment 2)
C. I. Pigment Yellow 127 Pigment 1 was prepared except that barium sulfate was not added. I. Pigment Yellow 127 Pigment 1 was prepared in the same manner as C.I. I. Pigment Yellow 127 Pigment 2 was obtained.

(Preparation of CI Pigment Red 57-1 Pigment 1)
A solution is prepared by adding 22.5 parts of 1-amino-4-4methylbenzene-2-sulfonic acid, 4.2 parts of sodium hydroxide and 400 parts of pure water. Add 25 parts of 35% hydrochloric acid to the solution and cool to 5 ° C. Further, 5 parts of sodium nitrite and 15 parts of pure water were added and stirred at 5 degrees for 60 minutes to prepare a diazo solution. Further, 17.0 parts of β-oxynaphthoic acid and 10 parts of sodium hydroxide were added to 600 parts of pure water, and 1000 parts of pure water was further added to prepare a coupling solution.
To 380 parts of the coupling liquid, 450 parts of the diazo liquid, 10 parts of rosin resin powder and 10 parts of barium sulfate (manufactured by Wako Pure Chemical Industries, Ltd.) were added dropwise at 20 ° C. over 2 hours, and then for 2 hours. The coupling reaction was completed by stirring as described above. Further, the obtained azo pigment slurry was heated to 90 ° C. and aged at 90 ° C. for 30 minutes, whereby a yellow pigment was obtained. This is filtered and washed with water to obtain a water-containing press cake. The presscake was dried at 90 ° C. for 20 hours and 96 parts of C.I. I. Pigment Red 57-1 pigment was obtained.

(Preparation of CI Pigment Red 57-1 Pigment 2)
C. I. Pigment Red 57-1 Pigment 1 was prepared except that barium sulfate was not added. I. Pigment Red 57-1 Pigment 1 was prepared in the same manner as C.I. I. Pigment Red 57-1 Pigment 2 was obtained.

<Toner preparation>
(Preparation of resin particle dispersion 1)
Styrene (manufactured by Wako Pure Chemical Industries): 325 parts n-butyl acrylate (manufactured by Wako Pure Chemical Industries): 75 parts β-carboxyethyl acrylate (manufactured by Rhodia Nikka): 9 parts 1'10 decanediol diacrylate (manufactured by Shin-Nakamura Chemical): 1 .5 parts dodecanethiol (manufactured by Wako Pure Chemical Industries): 2.7 parts A solution obtained by dissolving 4 parts of the anionic surfactant Dowfax (manufactured by Dow Chemical Co., Ltd.) in 550 parts of ion-exchanged water in which the above components are mixed and dissolved. The mixture was dispersed and emulsified in a flask and stirred and mixed slowly for 10 minutes. Further, 50 parts of ion-exchanged water in which 6 parts of ammonium persulfate was dissolved was added. Next, after sufficiently purging nitrogen in the flask sufficiently, the solution in the flask was heated with stirring in an oil bath to 70 ° C., and emulsion polymerization was continued as it was for 5 hours, and an anionic property with a solid content of 41%. A resin particle dispersion 1 was obtained.
The resin particles in the resin particle dispersion 1 had a center particle size of 196 nm, a glass transition temperature of 51.5 ° C., and a weight average molecular weight Mw of 32400.

(Preparation of resin particle dispersion 2)
Styrene (manufactured by Wako Pure Chemical Industries): 280 parts n-butyl acrylate (manufactured by Wako Pure Chemical Industries): 120 parts β-carboxyethyl acrylate (manufactured by Rhodia Nikka): 9 parts The above components are mixed and dissolved in an anionic surfactant Dow A solution obtained by dissolving 1.5 parts of fax (manufactured by Dow Chemical Co., Ltd.) in 550 parts of ion-exchanged water was dispersed and emulsified in a flask, and 0.4 parts of ammonium persulfate was further dissolved while stirring and mixing slowly for 10 minutes. 50 parts of ion exchange water was added. Next, after sufficiently replacing the nitrogen in the flask sufficiently, the solution in the flask was heated with stirring in an oil bath until it reached 70 ° C., and emulsion polymerization was continued as it was for 5 hours, and an anionic property with a solid content of 42%. A resin particle dispersion 2 was obtained.
The resin particles in the resin particle dispersion 2 had a center particle size of 150 nm, a glass transition temperature of 53.2 ° C., a weight average molecular weight Mw of 41,000, and a number average molecular weight Mn of 25,000.

(Preparation of Colorant Particle Dispersion 1)
C. I. Pigment Yellow 74 pigment: 1 part by weight anionic surfactant (manufactured by Nippon Oil & Fats Co., Ltd .: Nurex R): 2 parts ion exchange water: 220 parts After the dispersion, a dispersion process is performed for 15 minutes at a pressure of 245 Mpa using an optimizer (counter collision type wet pulverizer: manufactured by Sugino Machine). Dispersion 1 was obtained.

(Preparation of colorant particle dispersions 2 to 8)
C. I. Pigment Yellow 74 Pigment 1 was changed to C.I. I. A colorant dispersion 2 having a colorant particle center particle size of 295 nm was prepared in the same manner as in the preparation of the colorant particle dispersion 1, except that the pigment yellow 74 pigment 2 was used.
Similarly, C.I. I. Pigment Yellow 74 Pigment 1 was changed to C.I. I. A colorant dispersion 3 having a colorant particle central particle size of 160 nm was prepared in the same manner as in the preparation of the colorant particle dispersion 1, except that the pigment yellow 74 pigment 3 was used.

Similarly, C.I. I. Pigment Yellow 74 Pigment 1 was changed to C.I. I. A colorant dispersion 4 having a colorant particle central particle size of 210 nm was prepared in the same manner as in the preparation of the colorant particle dispersion 1, except that the pigment yellow 74 pigment 4 was used.
Similarly, C.I. I. Pigment Yellow 74 Pigment 1 was changed to C.I. I. A colorant dispersion 5 having a colorant particle central particle size of 181 nm was prepared in the same manner as in the preparation of the colorant particle dispersion 1, except that the pigment yellow 127 pigment 1 was used.

Similarly, C.I. I. Pigment Yellow 74 Pigment 1 was changed to C.I. I. A colorant dispersion liquid 6 having a colorant particle center particle size of 310 nm was prepared in the same manner as in the preparation of the colorant particle dispersion liquid 1 except that the pigment yellow 127 pigment 2 was used.
Similarly, C.I. I. Pigment Yellow 74 Pigment 1 was changed to C.I. I. A colorant dispersion 7 having a colorant particle center particle size of 165 nm was prepared in the same manner as in the preparation of the colorant particle dispersion 1, except that the pigment red 57-1 pigment 1 was used.
Similarly, C.I. I. Pigment Yellow 74 Pigment 1 was changed to C.I. I. A colorant dispersion 8 having a colorant particle center particle size of 354 nm was prepared in the same manner as in the preparation of the colorant particle dispersion 1, except that the pigment red 57-1 pigment 2 was used.

(Preparation of release agent particle dispersion 1)
Paraffin wax HNP9 (melting point 75 ° C .: manufactured by Nippon Seiki): 45 parts Cationic surfactant Neogen RK (Daiichi Kogyo Seiyaku): 5 parts Ion exchange water: 200 parts The above ingredients are mixed and heated to 100 ° C., After sufficiently dispersing with IKA Ultra Turrax T50, it was dispersed with a pressure discharge type gorin homogenizer, and a release agent particle dispersion 1 having a release agent particle central particle size of 196 nm and a solid content of 22.0% was obtained. Obtained.

-Production of Toner A-
Resin particle dispersion 1: 106 parts Resin particle dispersion 2: 36 parts Colorant particle dispersion 1: 30 parts Release agent particle dispersion 1: 91 parts In a round stainless steel flask, the above components were mixed with Ultra Turrax T50. A sufficiently mixed and dispersed solution was obtained.
Next, 0.4 parts of polyaluminum chloride was added to this solution to produce core aggregated particles, and the dispersion operation was continued using an ultra turrax. Further, the solution in the flask was heated to 49 ° C. with stirring in an oil bath for heating and held at 49 ° C. for 60 minutes, and then 36 parts of the resin particle dispersion 1 was gradually added thereto to form core / shell aggregated particles. Was made. Thereafter, 0.5 mol / L sodium hydroxide aqueous solution was added to adjust the pH of the solution to 5.6, and then the stainless steel flask was sealed and heated to 96 ° C. while continuing stirring using a magnetic seal. After maintaining the time, the mixture was cooled to obtain a yellow toner having a colorant concentration of 5%.

  Next, the black toner dispersed in the solution was filtered, thoroughly washed with ion-exchanged water, and then subjected to solid-liquid separation by Nutsche suction filtration. This was further redispersed in 3 L of ion exchanged water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. This was repeated five more times, and when the filtrate had a pH of 7.01, an electrical conductivity of 9.8 μS / cm, and a surface tension of 71.1 Nm, solid-liquid separation was performed using a No5A filter paper by Nutsche suction filtration. The obtained solid material made of yellow toner was vacuum-dried for 12 hours to obtain toner A having an average particle size of 6.4 μm.

-Production of Toner B-
A toner B having an average particle size of 6.3 μm was obtained in the same manner as in the preparation of the toner particles A except that the colorant particles 1 were changed to the colorant particles 2 in the preparation of the toner A.

-Production of Toner C-
A toner C having an average particle diameter of 6.4 μm was obtained in the same manner as in the preparation of the toner particles A except that the colorant particles 1 were changed to the colorant particles 3 in the preparation of the toner A.

-Production of Toner D-
Toner A having an average particle diameter of 6.0 μm was obtained in the same manner as in the preparation of toner particle A except that colorant particle 1 was changed to colorant particle 4 in the preparation of toner A.

-Production of Toner E-
A toner E having an average particle size of 6.3 μm was obtained in the same manner as in the preparation of the toner particles A except that the colorant particles 1 were changed to the colorant particles 5 in the preparation of the toner A.

-Production of Toner F-
In the preparation of the toner A, a toner F having an average particle diameter of 6.9 μm was obtained in the same manner as the preparation of the toner particles A except that the colorant particles 1 were changed to the colorant particles 6.

-Production of Toner G-
In the preparation of the toner A, the average particle diameter is 6.0 μm in the same manner as the preparation of the toner particles A except that the colorant particles 1 are changed to the colorant particles 7 and the pigment concentration in the toner is adjusted to 7%. Toner G was obtained.

-Production of Toner H-
In the preparation of the toner A, the average particle diameter of 6.5 μm is obtained in the same manner as the preparation of the toner particles A except that the colorant particles 1 are changed to the colorant particles 8 and the pigment concentration in the toner is adjusted to 7%. Toner H was obtained.

<External additive>
As an external additive, 1.5 parts of silicon oxide (RY50: manufactured by Nippon Aerosil Co., Ltd.) was added to each of toners A to H using a Henschel mixer to obtain externally added toners A to H, respectively.

<Manufacture of carriers>
Ferrite particles (average particle size 50 μm, volume electric resistance 10 ⁸ Ω · cm): 100 parts Toluene: 14 parts Perfluorooctylethyl acrylate / methyl methacrylate copolymer (copolymerization ratio 40:60, Mw = 50,000): 1 .6 parts carbon black (VXC-72; manufactured by Cabot Corporation): 0.12 parts cross-linked melamine resin (number average particle diameter; 0.3 μm): 0.3 parts Dispersed with a stirrer to prepare a film-forming solution. The coating liquid and ferrite particles are placed in a vacuum degassing kneader and stirred at 60 ° C. for 30 minutes, and then the pressure is reduced to distill off toluene to form a resin film on the ferrite particle surface. Manufactured.

<Production of developer>
94 parts of carrier and 6 parts of external toner A were mixed for 5 minutes with a V-type blender to prepare Developer 1. Similarly, 94 parts of carrier and 6 parts of externally added toners B to H were mixed in a V-type blender for 5 minutes to prepare developers 2 to 8, respectively.

<Examples 1-5, Comparative Examples 1-3>
The following evaluation was performed using the obtained developer. The results are shown in Table 1.
(Evaluation of image density)
In Table 1, the developer is DocuCenterColor400CP (manufactured by Fuji Xerox Co., Ltd.), the toner amount is adjusted to 4.5 g / m ^2, and an image of 4 × 4 cm is formed using C2 paper. The image density was measured using Xrite 938 (manufactured by Xrite).

(Evaluation of transparency)
In Table 1, an image of 4 × 4 cm was prepared using 4.5 g / m ² toner and OHP using DocuCenterColor400CP (manufactured by Fuji Xerox Co., Ltd.) as a developer. Using a fully automatic haze meter (TC-HIII DP type, manufactured by Tokyo Denshoku Co., Ltd.), the ratio of the scattered light to the total transmitted light was measured according to JIS K7105: 81 “Plastic Optical Properties Test Method”. . In the present invention, haze of less than 15% is indicated by ◎, 15% or more and less than 20% is indicated by ○, 20% or more and less than 30% by Δ, and 30% or more by ×.

  From Table 1, it can be seen that Example 1 has high image density and transparency.

<Examples 6 to 7, Comparative Example 4>
(Secondary color evaluation)
Further, as the overlay transparency evaluation (secondary color evaluation), using the developer shown in Table 2 using DocuCentreColor400CP (manufactured by Fuji Xerox Co., Ltd.), the toner amounts in the order of yellow and magenta so that yellow comes to the top surface. Was adjusted to 4.5 g / m ² , an image of 4 × 4 cm was prepared using C2 paper, and the image density was measured using Xrite 938 (manufactured by Xrite) in the same manner as the evaluation of the image density. Furthermore, L * was evaluated as an overlay transparency evaluation. L * measurement was evaluated with Xrite 938 (manufactured by Xrite) in the same manner as the image density evaluation. In the evaluation, L * was measured when the image density was 1.4 ≦, and 40 or more was evaluated as ◯, 35 or more and less than 40 as Δ, and 30 or more and less than 35 as x. The results are shown in Table 2.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus of the present invention.

Explanation of symbols

1Y, 1M, 1C, 1K Photoconductor 2Y, 2M, 2C, 2K Charging roller 3Y, 3M, 3C, 3K Laser beam 3 Exposure device 4Y, 4M, 4C, 4K Developing device 5Y, 5M, 5C, 5K Primary transfer roller 6Y, 6M, 6C, 6K Photoconductor cleaning devices 10Y, 10M, 10C, 10K Station 20 Intermediate transfer belt 22 Drive roller 24 Support roller 26 Secondary transfer roller 28 Fixing device 30 Intermediate transfer member cleaning device P Recording paper

Claims (8)

  A yellow toner for electrostatic charge development, comprising a binder resin, a colorant, a release agent, and barium, wherein the barium content is 0.3% by mass or more.   A resin particle dispersion in which binder resin particles are dispersed, a colorant dispersion in which a colorant obtained by synthesis in the presence of a barium compound is dispersed, and a release agent dispersion in which a release agent is dispersed are mixed. Through one or more metal salts containing polyaluminum chloride to form aggregated particles, and by heating the aggregated particles, fusing and coalescing and coalescing The yellow toner for electrostatic charge development according to claim 1, which is manufactured.   An electrostatic charge developing developer comprising the yellow toner for electrostatic charge developer according to claim 1.   A magenta toner for electrostatic charge development, comprising a binder resin, a colorant, a release agent, and barium, wherein the barium content is 0.3% by mass or more.   A resin particle dispersion in which binder resin particles are dispersed, a colorant dispersion in which a colorant obtained by synthesis in the presence of a barium compound is dispersed, and a release agent dispersion in which a release agent is dispersed are mixed. Through one or more metal salts containing polyaluminum chloride to form aggregated particles, and by heating the aggregated particles, fusing and coalescing and coalescing The magenta toner for electrostatic charge development according to claim 4, which is manufactured.   An electrostatic charge developing developer comprising the magenta toner for electrostatic charge developer according to claim 4. A developing device for developing the electrostatic latent image formed on the surface of the image carrier using the electrostatic charge developing developer according to claim 3 to form a toner image;
At least one selected from the group consisting of the image carrier, a charging device for charging the surface of the image carrier, and a cleaning device for removing toner remaining on the surface of the image carrier;
A process cartridge comprising: An image carrier,
A charging device for charging the surface of the image carrier;
An exposure device for forming an electrostatic latent image on the surface of the charged image carrier;
A developing device for developing the electrostatic latent image formed on the image carrier using the electrostatic charge developing developer according to claim 3 to form a toner image;
A transfer device for transferring the toner image to a transfer target;
A cleaning device for removing toner remaining on the surface of the image carrier;
An image forming apparatus comprising:

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