JP4111358B2 - Color toner and manufacturing method thereof - Google Patents

Description

【００７９】
これらの着色粒子は、いずれも該着色粒子１００重量部に対して、疎水性シリカ（Ｒ−９７２：日本アエロジル製）０．６重量部、及び疎水性チタニア（Ｔ−８０５：日本アエロジル製）０．６重量部を添加混合して、各着色粒子に対応するトナーである「実施例トナーＡ１〜Ａ５」、「実施例トナーＢ１〜Ｂ５」及び「比較例トナー１，２」を得た。
【００８０】
更にこれらのトナーは何れも、表面にスチレン−メチルメタクリレート共重合体樹脂の被覆層を有し、体積平均粒径が３０μｍであるフェライトコアキャリアとトナー濃度が１０重量％となる様に混合し、二成分現像剤として評価を行った。
【００８１】
上記の現像剤を使用して画像の出力を行い性能評価を行った。画像形成装置としてはコニカ社製カラー複写機Ｋｏｎｉｃａ９０２８を使用して画像の出力を行った。
【００８２】
ＯＨＰ透過性
ＯＨＰシート上に形成された画像の分光透過率を日立製作所製「３３０型自記分光光度計」により測定し、５７０ｎｍの波長に於ける可視分光透過率を求め、ＯＨＰ画像の透明性の尺度とした。尚、ＯＨＰシート上へのトナーの付着量は０．７±０．０５ｍｇ／ｃｍ²とし、トナーの担持されていないＯＨＰシートを分光光度測定のリファレンスとした。
【００８３】
耐光性
普通紙上に形成した画像に対しカーボンアーク燈を４８時間照射し、照射前後での画像の色度を測定し、照射前に対する色差の変化を調べた。色度の測定はマクベス社製分光光度計「カラーアイＣＥ−７０００」を使用した。
【００８４】
キャリア汚染
各トナーを使用した現像剤を、単体で駆動できる構造に改造した現像器中に入れ、現像器による攪拌を１２０分間行った後に現像剤を回収し、更に界面活性剤によりトナーを洗い流してキャリアのみを回収した。このキャリア２０ｇをメチルエチルケトン２５ｍｌ中に入れて攪拌し、キャリアの被覆層であるスチレン−メチルメタクリレート樹脂を溶解した後にキャリアコアを磁力により保持しながらこの溶液を回収した。得られた溶液の４００ｎｍに於ける吸光度を日立製作所製「３３０型自記分光光度計」により測定し、イエロー着色剤によるキャリア粒子の汚染の度合いを評価した。
【００８５】
評価結果を表２にまとめて示す。
【００８６】
【表２】

【００８７】
表２より伺い知れる様に、本発明の着色剤を使用した実施例トナーでは着色剤の分散性に優れる事により、何れも良好なＯＨＰ透過性を示すと共に、耐光性、耐褪色性に優れ、長期に亘り色度が維持されている。又、キャリアとの混合に於いても着色剤の遊離によるキャリアの汚染は生じていない。
【００８８】
比較例トナー１では顔料の分散性に劣り、ＯＨＰでの発色が不良であった。比較例トナー２では染料の耐光性に劣り、褪色が生じて色度の変動を発生した。更に、比較例トナー１，２共に着色剤の遊離によるキャリアの汚染を発生した。
【００８９】
【発明の効果】
本発明により、バインダー樹脂中への分散性に優れ、且つ耐光性，耐褪色性に於いても良好な着色剤を見出し、小粒径で粒度分布の狭い優れたカラートナーとその製造方法を提供することが出来る。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color toner that can be used in an image output device such as a copying machine or a printer using electrophotography, and a method for manufacturing the color toner.
[0002]
[Prior art]
In recent years, in image output devices such as copiers and printers using electrophotography, toner particles have been actively reduced in size for the purpose of improving image quality. Improvement is the purpose.
[0003]
However, in the case of a two-component developer composed of a toner and a carrier, various problems in development performance such as development fog, toner scattering, and image density deterioration with time are more noticeable with the use of a small-diameter toner. It has become. The main cause of these problems is that in the case of a toner having a reduced diameter, physical adhesion such as van der Waals force acting between carrier particles is strengthened. Small diameter and fine particle components in the toner particle size distribution accumulate on the carrier surface and inhibit frictional charging with the newly replenished toner. For this reason, it is conceivable that the problem of so-called selective development, in which sufficient frictional charging performance cannot be imparted and, as a result, weakly charged toner is generated and fogging and toner scattering occur, becomes significant.
[0004]
To solve this problem of selective development, a method of reducing the fine particle component in the toner by narrowing the particle size distribution of the toner is used as an effective means for achieving high image quality while avoiding the above problem. These toners having a narrow particle size distribution can be generally obtained by performing a classification operation in the toner manufacturing process even in the so-called pulverization method, but in recent years, a toner manufacturing method by a polymerization method has been applied. By doing so, it can be obtained efficiently.
[0005]
Such a technique for improving the image quality by reducing the diameter of the toner is expected to be effective not only in conventional monochrome image formation but also in application to a full-color image formation process. In such full-color image formation, since a variety of color reproduction is required by superimposing a plurality of color toners, when a small diameter toner is used, the color mixing of the superimposed toners is excellent, and color reproduction is achieved. The area can be expanded. This is considered to be due to the fact that the heat capacity of the individual toner particles is reduced by the small-diameter toner, and that the melting and mixing of the toner particles during fixing greatly contributes. In addition, since the surface of the fixed image is smoothed by the small-diameter toner, an effect of improving the image quality and expanding the color reproduction range is expected.
[0006]
On the other hand, in the color toner, the dispersibility of the colorant is an important issue from the viewpoint of the color development performance, and a fine and uniform dispersion of the colorant is required. That is, when the dispersed particle diameter of the colorant is coarse, the color developability of the color toner is impaired, and in particular, sufficient color reproduction cannot be achieved when a plurality of colors are mixed. As the most remarkable problem, the transparency of the toner layer is impaired due to the presence of coarse colorant particles, so that the color developability particularly in an image projected by an overhead projector (hereinafter also referred to as an OHP image) is deteriorated.
[0007]
As colorants for color toners, dyes or pigments have been generally used. However, in the case of using a dye having compatibility with a binder resin as a colorant for the above-mentioned dispersibility problem, Although it is excellent in dispersibility, it has a problem in that it is inferior in light resistance, so that fading or the like is likely to occur, and stable color development performance over a long period of time cannot be maintained. On the other hand, although the pigments are good in terms of weather resistance, they are generally difficult to uniformly disperse in the binder resin because of their high cohesiveness. Although a technique for using a pigment as a processing color material by a flushing method, a master batch method, or the like has been reported in advance, an increase in manufacturing man-hours and an increase in cost are inevitable.
[0008]
In addition, in the toner production method by the polymerization method advantageous for production with respect to the above-mentioned reduction in toner diameter, there are difficulties inherent in the production method regarding the application of the colorant. For example, resin particles generated in the polymerization process If the affinity between the colorant and the colorant is low, poor incorporation of the colorant into the toner particles to be produced occurs, and the problem of leading to carrier contamination due to the generation of the free colorant, and the colorant to the polymerization system Problems such as formation of oligomer components and residual monomers due to the inhibition of the progress of the polymerization reaction due to the intervention have been pointed out.
[0009]
[Problems to be solved by the invention]
An object of the present invention is to find a colorant which is excellent in dispersibility in a binder resin and has good weather resistance and fading resistance, and provides an excellent color toner having a small particle size and a narrow particle size distribution. It is in.
[0010]
[Means for Solving the Problems]
The object of the present invention is achieved by adopting the following configuration.
[0011]
[1] a polymer fine particles obtained by emulsion polymerization is prepared by a method in which a plurality association agglomeration, the volume average particle diameter of 3 to 8 [mu] m, and coefficient of variation of the particle size distribution calculated from the volume particle size distribution is less than 30 a der Luke Ratona, C. as a coloring agent in the color toner I. A color toner comprising a compound classified as Solvent Yellow 93.
[0012]
[2] Manufactured by a method in which a plurality of polymer fine particles obtained by emulsion polymerization are aggregated and aggregated, the volume average particle size is 3 to 8 μm, and the coefficient of variation of the particle size distribution calculated from the volume particle size distribution is less than 30 a der Luke Ratona, C. as a coloring agent in the color toner I. A color toner comprising a compound classified as Solvent Yellow 162.
[0017]
[ 3 ] The color toner according to [1] or [2] is associated with a dispersion of the polymer fine particles by adding a coagulant having a critical coagulation concentration or higher and an organic solvent infinitely soluble in water. A method for producing a color toner, characterized by being prepared.
[0018]
As a result of intensive studies on the improvement of the dispersibility of the colorant, the present inventors have found a specific yellow colorant that is excellent in dispersibility in the binder resin, and that is also excellent in weather resistance and fading resistance, The present invention has been reached.
[0019]
In particular, when the yellow colorant is used in a toner production method by a polymerization method, a toner having a small particle size and a narrow particle size distribution is obtained by exhibiting uniform dispersion in the toner particles without generating colorant liberation. Can be obtained efficiently. The obtained toner achieves extremely good color development performance, particularly improvement in color development in an OHP image, and avoids the problem of selective development associated with the reduction in the toner particle size, and is good and stable. The development performance can be demonstrated over a long period of time.
[0020]
Incidentally, the coefficient of variation of volume-average particle size and particle size distribution of the present invention, the Coulter particle size analyzer "Coulter Multisizer II", is calculated from the volume particle size distribution measured using a 100μm aperture Use the value.
[0021]
If the volume average particle size of the toner is larger than 7 μm, the saturation of the color image tends to be reduced particularly in an OHP image, and if it is smaller than 3 μm, the charging property is deteriorated during development, and the unexposed portion is fogged. Is likely to occur.
[0022]
The present invention is described in detail below.
[0023]
The yellow colorant used in the toner of the present invention is C.I. I. Compounds classified as Solvent Yellow 93, and / or C.I. I. These compounds are classified as Solvent Yellow 162 , and the amount of these added is 0.1 to 15 parts by weight, preferably 1.0 to 10 parts by weight, based on 100 parts by weight of the binder resin.
[0024]
Here, C.I. I. Is an abbreviation for COLOR INDEX (THE THIRDEDITION), and as is well known, is issued by THE SOCIETY OF DYERS AND COLORISTS. For example, “C.I. Solvent Yellow 93” refers to the compound No. registered therein. Represents.
[0025]
For the method for producing a toner using a colorant of the present invention, Ru have use the method for a plurality association coagulate the polymer fine particles obtained by emulsifying polymerization. More specifically, as a polymerization step, first, the yellow colorant of the present invention is dispersed in an aqueous solution with a surfactant in advance, and then emulsion polymerization is performed by adding a water-soluble radical polymerization initiator and a polymerizable monomer. . After obtaining the polymer particles containing the yellow colorant of the present invention, then as an associating step, the method of JP-A-5-115572, that is, with respect to the flocculant and water above the critical aggregation concentration of the polymer particle dispersion A plurality of the polymer particles are associated with each other by adding an infinitely soluble organic solvent to produce associative colored particles. The toner particle size of the present invention can be achieved by appropriately adjusting the addition amount of the flocculant, organic solvent and other additives in this association step, or the polymer composition.
[0026]
As the polymerizable monomer, a hydrophobic monomer is an essential constituent component, and a hydrophilic monomer and a crosslinkable monomer are used as necessary.
[0027]
1) Hydrophobic monomer The hydrophobic monomer constituting the monomer component is not particularly limited, and conventionally known monomers can be used. Moreover, it can be used combining 1 type (s) or 2 or more types so that the required characteristic may be satisfy | filled.
[0028]
Specifically, monovinyl aromatic monomers, (meth) acrylic acid ester monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers, diolefin monomers , Halogenated olefin monomers and the like can be used.
[0029]
Examples of vinyl aromatic monomers include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-methoxy styrene, p-phenyl styrene, p-chloro styrene, p-ethyl styrene, p. -N-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2, Examples thereof include styrene monomers such as 4-dimethylstyrene and 3,4-dichlorostyrene and derivatives thereof.
[0030]
Examples of acrylic monomers include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, methyl methacrylate, methacrylic acid. Examples include butyl acid, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and the like.
[0031]
Examples of vinyl ester monomers include vinyl acetate, vinyl propionate, and vinyl benzoate.
[0032]
Examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether and the like.
[0033]
Examples of the monoolefin monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene and the like.
[0034]
Examples of the diolefin monomer include butadiene, isoprene, chloroprene and the like.
[0035]
2) Hydrophilic monomer The hydrophilic monomer constituting the monomer component is not particularly limited, and conventionally known monomers can be used. Moreover, it can be used combining 1 type (s) or 2 or more types so that the required characteristic may be satisfy | filled.
[0036]
For example, amine-based compounds such as carboxyl group-containing monomers, sulfonic acid group-containing monomers, primary amines, secondary amines, tertiary amines, and quaternary ammonium salts can be used.
[0037]
Examples of the carboxylic acid group-containing monomer include fumaric acid, maleic acid, itaconic acid, cinnamic acid, maleic acid monobutyl ester, maleic acid monooctyl ester and the like.
[0038]
Examples of the sulfonic acid group-containing monomer include styrene sulfonate, allylsulfosuccinic acid, octyl allylsulfosuccinate, and the like.
[0039]
Examples of amine compounds include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, 3-dimethylaminophenyl acrylate, 2-hydroxy-3-methacryloxypropyltrimethylammonium salt, and the like. .
[0040]
3) A crosslinkable monomer may be added to improve the properties of the crosslinkable monomer polymer particles. Examples of the crosslinkable monomer include those having two or more unsaturated bonds such as divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and diallyl phthalate.
[0041]
In many cases, the monomer according to the present invention is appropriately selected within the range of 99.9 to 85 weight percent for the hydrophobic monomer and 0.1 to 15 weight percent for the hydrophilic monomer.
[0042]
For the purpose of adjusting the chain transfer agent molecular weight, a commonly used chain transfer agent can be used. The chain transfer agent is not particularly limited, and mercaptans such as octyl mercaptan, dodecyl mercaptan, and t-dodecyl mercaptan are used.
[0043]
Polymerization initiator The radical polymerization initiator used in the present invention can be appropriately used as long as it is water-soluble. For example, persulfates (potassium persulfate, ammonium persulfate, etc.), azo compounds (4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis (2-amidinopropane) salts, etc.), An oxide compound etc. are mentioned.
[0044]
Furthermore, the radical polymerization initiator can be combined with a reducing agent as necessary to form a redox initiator. By using a redox initiator, the polymerization activity is increased, the polymerization temperature is lowered, and the polymerization time can be further shortened.
[0045]
The polymerization temperature may be any temperature as long as it is equal to or higher than the lowest radical generation temperature of the polymerization initiator. For example, a range of 50 ° C. to 80 ° C. is used. However, it is also possible to perform polymerization at room temperature or higher by using a polymerization initiator that starts at room temperature, for example, a combination of hydrogen peroxide and a reducing agent (ascorbic acid or the like).
[0046]
Surfactants Surfactants include sulfonates (sodium dodecylbenzene sulfonate, sodium arylalkyl polyether sulfonate, 3,3-disulfone diphenylurea-4,4-diazo-bis-amino-8-naphthol-6 Sodium sulfonate, ortho-carboxybenzene-azo-dimethaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-6-sodium sulfonate, etc.), sulfuric acid Ester salt (sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.), fatty acid salt (sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium oleate) Etc.), and the like.
[0047]
As the release agent, conventionally known release agents can be used, such as low molecular weight polyethylene, low molecular weight polypropylene, oxidized polyethylene and polypropylene, acid-modified polyethylene and polypropylene, carnauba wax, fatty acid amide and the like. I can list. Regarding the addition of the release agent, since the transparency of the color toner is impaired, the addition amount is preferably as small as possible, and the addition amount is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin.
[0048]
Similarly, a known charge control agent is used as the charge control agent. However, it may not be necessary when a monomer having a polar group is copolymerized on the surface of the polymer particles. The polar group mentioned here represents a group having a charge regardless of positive or negative, such as a carboxyl group, a sulfonic acid group, an amino group, and an ammonium base.
[0049]
As the charge control agent, a conventionally known one can be used, but it is preferably colorless or white because it constitutes a part of the color toner. Specific examples include zinc salts of salicylic acid or salicylic acid derivatives.
[0050]
Dispersion of Colorant The colorant is dispersed in the aqueous phase at a surfactant concentration of CMC or higher. As a dispersion method, mechanical stirring, for example, a sand grinder, sonication, for example, ultrasonic dispersion, pressure dispersion, for example, Manton Gorin, or the like is used.
[0051]
Production of polymer particles (emulsion polymerization)
In the method for producing pigment-containing polymer particles of the present invention, the surfactant dispersion concentration of the colorant dispersion is diluted until it becomes CMC or less. Dissolving a water-soluble radical polymerization initiator in the dispersion, adding an ethylenically unsaturated monomer, and performing aqueous precipitation polymerization to obtain pigment-containing polymer particles, wherein the colorant is incorporated into the polymer particles Contain.
[0052]
Associating and fusing process A non-spherical toner is produced by associating and fusing using polymer particles produced by emulsion polymerization. As the associative fusion method, non-spherical particles are produced by the method of Japanese Patent Application Laid-Open No. 5-115572, that is, a method of adding an aggregating agent having a critical aggregation concentration or higher of the polymer particle dispersion and an organic solvent that is infinitely soluble in water. It is possible to produce.
[0053]
Regardless of the production method, the toner of the present invention may use various kinds of conventionally known inorganic fine particles, organic fine particles, lubricants and the like as external additives.
[0054]
Inorganic fine particles As inorganic fine particles, various inorganic oxides, nitrides, borides and the like can be suitably used, for example, silica, alumina, titania, zirconia, barium titanate, aluminum titanate, strontium titanate, silicon nitride, etc. It is done. Furthermore, it is preferable that these inorganic fine particles are subjected to a hydrophobic treatment with various coupling agents.
[0055]
Organic fine particles As the organic fine particles, various resin fine particles composed of vinyl resin, silicone resin, fluorine resin, melamine resin, and the like can be suitably used.
[0056]
As the lubricant, various metal salts such as aluminum, sodium, strontium, magnesium, calcium, and zinc of various higher fatty acids such as stearic acid and oleic acid can be used.
[0057]
As a carrier when the toner of the present invention is used as a two-component developer, either a non-coated carrier composed only of magnetic material particles such as iron or ferrite, or a resin-coated carrier whose magnetic material particle surface is coated with a resin or the like is used. May be used. The average particle diameter of the carrier is preferably 15 to 100 μm in terms of volume average particle diameter. Conventionally known materials such as styrene-acrylic resin can be used as the coating resin.
[0058]
The color image forming method to which the yellow toner of the present invention is applied is not particularly limited. For example, after repeated development on a photoconductor to form a superimposed image of color toners on the photoconductor An image forming method that performs batch transfer onto transfer paper such as paper, or an image formed on a photoconductor is sequentially transferred to an intermediate transfer body, etc., and a color toner superimposed image is formed on the intermediate transfer body and then transferred. A method of transferring to paper can be used.
[0059]
【Example】
EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this.
[0060]
Example Production of Colored Particle A1 As a yellow colorant of the present invention, C.I. I. 11 g of Solvent Yellow 93 (OPLAS YELLOW 140: manufactured by Orient Chemical Co., Ltd.) was added to a solution obtained by dissolving 5.6 g of sodium dodecyl sulfate in 120 ml of pure water, and the water of the yellow colorant was added by stirring and applying ultrasonic waves. A dispersion was prepared in advance. Also, an emulsified dispersion was prepared in advance by emulsifying low molecular weight polypropylene (number average molecular weight = 3000) in water so that the solid concentration was 30% by weight with a surfactant while heating.
[0061]
The yellow colorant dispersion is mixed with 60 g of a low molecular weight polypropylene emulsified dispersion. Further, 220 g of a styrene monomer, 40 g of an n-butyl acrylate monomer, 12 g of a methacrylic acid monomer, and t-dodecyl mercaptan as a chain transfer agent. After adding 5.4 g and 2100 ml of degassed pure water, the temperature was raised to 70 ° C. while stirring in a nitrogen stream. Next, 4.3 g of potassium persulfate as a polymerization initiator was dissolved in 440 ml of pure water and added, and the mixture was held at 70 ° C. for 3 hours for emulsion polymerization. The dispersion liquid of the colorant-containing polymer particles obtained in this manner is referred to as “Example polymerization liquid A1”.
[0062]
Subsequently, sodium hydroxide was added to 1000 ml of the polymerization liquid A1 of this example to adjust the pH to 7.5, 275 ml of a 2.7 mol% aqueous potassium chloride solution was added, and 180 ml of isopropyl alcohol was further added, and 85 ° C. The mixture was stirred and reacted for 6 hours. The obtained reaction liquid was filtered, washed with water, further dried and crushed to obtain colored particles.
[0063]
This colored particle is referred to as “Example colored particle A1”.
[0064]
Production of Example Colored Particles A2 “Example Colored Particles A2” were obtained in the same manner as in Example Colored Particles A1, except that the amount of 2.7 mol% potassium chloride aqueous solution added was changed to 340 ml.
[0065]
Production of Example Colored Particles A3 In 2500 ml of degassed pure water, 6 g of sodium dodecyl sulfate and 60 g of a low molecular weight polypropylene emulsified dispersion similar to those used in the production of Example Colored Particles A1 were mixed, and further 220 g of styrene monomer. Then, 40 g of n-butyl acrylate monomer, 15 g of methacrylic acid monomer, and 5.0 g of t-dodecyl mercaptan were added as a chain transfer agent, and the temperature was raised to 70 ° C. while stirring in a nitrogen stream. Next, 5.0 g of potassium persulfate as a polymerization initiator was dissolved in 440 ml of pure water and added, and held at 70 ° C. for 3 hours to carry out emulsion polymerization to obtain a dispersion of non-colored polymer particles. 140 ml of an aqueous dispersion of a yellow colorant similar to that used for the production of the particles 1 was added and further stirred at 70 ° C. for 1 hour to obtain a dispersion of colorant-containing polymer particles. This is designated as “Example polymerization liquid A3”.
[0066]
Next, sodium hydroxide was added to 1000 ml of this “Example polymerization solution A3” to adjust the pH to 7.5, 275 ml of 2.7 mol% aqueous potassium chloride solution was added, and 180 ml of isopropyl alcohol was further added. The mixture was stirred at 6 ° C. for 6 hours and reacted. The obtained reaction solution was filtered, washed with water, dried and crushed to obtain colored particles. This colored particle is referred to as “Example colored particle A3”.
[0067]
Production of Example Colored Particle A4 In 2500 ml of degassed pure water, 6 g of sodium dodecyl sulfate and 60 g of a low molecular weight polypropylene emulsified dispersion similar to those used in the production of Example Colored Particle A1 were mixed, and further 220 g of styrene monomer. Then, 40 g of n-butyl acrylate monomer, 15 g of methacrylic acid monomer, and 5.0 g of t-dodecyl mercaptan were added as a chain transfer agent, and the temperature was raised to 70 ° C. while stirring in a nitrogen stream. Next, 5.5 g of potassium persulfate as a polymerization initiator was dissolved in 440 ml of pure water and added, and held at 70 ° C. for 3 hours for emulsion polymerization to obtain a dispersion of non-colored polymer particles. This is designated as “Example polymerization liquid A4”.
[0068]
Next, 45 ml of an aqueous dispersion of a yellow colorant similar to that used in the production of Example Colored Particles 1 was added to 1000 ml of “Example Polymerization Solution A4”, and sodium hydroxide was further added to adjust pH = 7.5. Then, 320 ml of a 2.7 mol% aqueous potassium chloride solution was further added, 180 ml of isopropyl alcohol was further added, and the mixture was kept at 85 ° C. and stirred for 6 hours to carry out an association aggregation reaction. The obtained reaction solution was filtered, washed with water, dried and crushed to obtain colored particles. This colored particle is referred to as “Example colored particle A4”.
[0069]
Example Preparation of Colored Particles A5 Example 1000 ml of polymerization liquid A4 was adjusted to pH = 7.5 by adding sodium hydroxide, 320 ml of 2.7 mol% aqueous potassium chloride solution was added, and 170 ml of isopropyl alcohol was further added. The solution was added and held at 85 ° C. and stirred for 6 hours to carry out an aggregation aggregation reaction. Further, after cooling the obtained reaction liquid, 12 g of the same colorant used in the production of Example colored particles A1 was poured into a dispersion liquid dispersed in 3600 ml of isopropyl alcohol, and the temperature was raised to 65 ° C. again. After stirring for 6 hours and coloring the colored particles with a colorant, colored particles were obtained through cooling, filtration, washing with water, drying and crushing. This colored particle is referred to as “Example colored particle A5”.
[0070]
Example Colored Particles B1 to B5 Production Example Colorants used in the production of each of the colored particles A1 to A5 are C.I. I. Instead of Solvent Yellow 93, C.I. I. The colored particles obtained by the same production method as Example colored particles A1 to A5 except that Solvent Yellow 162 (Neopen Yellow 075: manufactured by BASF) was used are referred to as “Example colored particles B1 to B5”.
[0075]
Production Example of Comparative Colored Particle 1 In the production of the polymerization liquid A1, C.I. I. “Comparative Example Polymer 1” was obtained in the same manner except that Pigment Yellow 17 (KET Yellow 403: manufactured by Dainippon Ink, Inc.) was used. Furthermore, using the comparative polymerization liquid 1, “Comparative Example Colored Particles 1” was obtained in the same manner as in the production of Example Colored Particles A1.
[0076]
Production Example of Comparative Colored Particle 2 In the production of the polymerization liquid A1, C.I. I. Solvent. A “Comparative Example Polymerization Solution 2” was obtained in the same manner except that Yellow 77 (Kayaset Yellow G: manufactured by Nippon Kayaku Co., Ltd.) was used. Furthermore, using the comparative polymerization liquid 2, “Comparative Example Colored Particles 2” was obtained in the same manner as in the production of Example Colored Particles A1.
[0077]
Table 1 summarizes the volume average particle diameter and coefficient of variation of the above colored particles A1 to B5 in Examples and the colored particles 1 and 2 for comparison.
[0078]
[Table 1]

[0079]
These colored particles are all 0.6 parts by weight of hydrophobic silica (R-972: manufactured by Nippon Aerosil) and hydrophobic titania (T-805: manufactured by Nippon Aerosil) with respect to 100 parts by weight of the colored particles. It was added and mixed .6 parts by weight, a toner corresponding to the colored particles "example toner A1~A5" to give "example toner B1~B5"及 beauty "Comparative toner 1".
[0080]
Furthermore, all of these toners have a coating layer of a styrene-methyl methacrylate copolymer resin on the surface, and are mixed with a ferrite core carrier having a volume average particle size of 30 μm so that the toner concentration becomes 10% by weight. Evaluation was performed as a two-component developer.
[0081]
An image was output using the developer described above, and the performance was evaluated. As an image forming apparatus, a color copying machine Konica 9028 manufactured by Konica was used to output an image.
[0082]
The spectral transmittance of the image formed on the OHP transparent OHP sheet was measured with a “330 type automatic spectrophotometer” manufactured by Hitachi, and the visible spectral transmittance at a wavelength of 570 nm was determined. A scale. Incidentally, the amount of toner adhering onto the OHP sheet and 0.7 ± 0.05mg / cm ^2, and the OHP sheet that is not supported in the toner and the reference spectrophotometric measurement.
[0083]
The image formed on the light-resistant plain paper was irradiated with a carbon arc soot for 48 hours, the chromaticity of the image before and after the irradiation was measured, and the change in the color difference before the irradiation was examined. For the measurement of chromaticity, a spectrophotometer “Color Eye CE-7000” manufactured by Macbeth Co. was used.
[0084]
The developer using carrier-contaminated toner is put into a developer that has been modified to a structure that can be driven alone, and after stirring for 120 minutes, the developer is recovered, and the toner is washed away with a surfactant. Only the carrier was recovered. 20 g of this carrier was placed in 25 ml of methyl ethyl ketone and stirred, and after dissolving the styrene-methyl methacrylate resin as the carrier coating layer, this solution was recovered while holding the carrier core magnetically. Absorbance at 400 nm of the obtained solution was measured with a “330 self-recording spectrophotometer” manufactured by Hitachi, Ltd., and the degree of contamination of the carrier particles by the yellow colorant was evaluated.
[0085]
The evaluation results are summarized in Table 2.
[0086]
[Table 2]

[0087]
As can be seen from Table 2, the toners of the examples using the colorant of the present invention are excellent in dispersibility of the colorant, so that both show good OHP permeability, and are excellent in light resistance and fading resistance. The chromaticity is maintained for a long time. In addition, the carrier is not contaminated by the liberation of the colorant even when mixed with the carrier.
[0088]
In Comparative Example Toner 1, the dispersibility of the pigment was inferior and the color development with OHP was poor. In Comparative Example Toner 2, the light resistance of the dye was inferior, and fading occurred, causing a change in chromaticity. Further, both the toners of Comparative Examples 1 and 2 generated carrier contamination due to liberation of the colorant.
[0089]
【The invention's effect】
According to the present invention, a colorant excellent in dispersibility in a binder resin and having good light resistance and fading resistance is found, and an excellent color toner having a small particle size and a narrow particle size distribution and a method for producing the same are provided. I can do it.

Claims (3)

  A color produced by a method in which a plurality of polymer fine particles obtained by emulsion polymerization are aggregated and aggregated, having a volume average particle size of 3 to 8 μm, and a coefficient of variation in particle size distribution calculated from the volume particle size distribution of less than 30 C. as a colorant for the color toner. I. A color toner comprising a compound classified as Solvent Yellow 93.   A color produced by a method in which a plurality of polymer fine particles obtained by emulsion polymerization are aggregated and aggregated, having a volume average particle size of 3 to 8 μm, and a coefficient of variation in particle size distribution calculated from the volume particle size distribution of less than 30 C. as a colorant for the color toner. I. A color toner comprising a compound classified as Solvent Yellow 162. A color toner according to claim 1 or 2 is produced by associating a plurality of color toners by a method of adding a flocculant having a critical aggregation concentration or higher and an organic solvent infinitely soluble in water to the dispersion of polymer fine particles. A method for producing a color toner.