JPH11184161A - Toner mother particles, toner and developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the yellow toner mother particles, for developing an electrostatic charge image, capable of attaining sharpness and sufficient color reproducibility and development at the time of forming a full color image by using a full color copying machine or printer or the like, and to provide the yellow toner and the yellow developer each using these yellow toner mother particles. SOLUTION: These yellow toner mother particles, for developing an electrostatic charge image, contains a processed pigment (D) obtained by mechanically kneading a mixture comprising at least 3 components of an epindoridione pigment (A) represented by the formula, and an aqueous inorganic salt (B), and a water-soluble solvent (C), and then rinsing and removing the components (B) and (C). In the formula, each of R1 -R8 is, independently, an H or halogen atom and at least 3 of R1 -R4 are halogen atoms.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a yellow toner base particle for developing an electrostatic image used for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing, and the like, and the yellow toner. The present invention relates to a yellow toner and a yellow developer formed using mother particles. More specifically, when an image is formed using magenta, cyan, and black toners and the like, a clear and sufficient color reproducibility, a yellow toner mother particle for electrostatic image development including a novel epidridione pigment capable of obtaining color development, and The present invention relates to a yellow toner and a yellow developer formed using the yellow toner base particles.

[0002]

2. Description of the Related Art In recent years, the development of full-color images in copying machines, printers, and the like has been rapidly progressing, and their practical use has been greatly increased. However, compared to photographs and printed matter, it is hard to say that a full-color electrophotographic image currently in practical use has reached a satisfactory image quality. In recent years, with the progress and development of computers, high-definition televisions, and the like, there is a strong demand for a method of forming a higher-definition full-color image. For this reason, there is a strong demand for further improving the quality of full-color electrophotographic images.

In electrophotography, an electrostatic latent image is generally developed using toner. The methods are roughly classified into a method using a two-component developer in which a small amount of toner is dispersed in a medium called a carrier, and a method using a one-component developer without using a carrier. For full color electrophotography,
A two-component developer in which a carrier and a toner are mixed and used is often used.

In color image formation by full-color electrophotography, all colors are reproduced by using three color toners of three primary colors, yellow, magenta and cyan, and preferably four color blacks for inking. Things.
In this method, for example, light from a document is first subjected to analog or digital color separation and guided to a photoconductive layer of a photoreceptor to form an electrostatic latent image of the first color. Subsequently, the toner is held on a transfer material such as paper through a development and transfer process. Further, for the second and subsequent colors, the above-described steps are sequentially performed a plurality of times, and the toners of a plurality of colors are superimposed on the same material to be transferred, and a final full-color image is obtained by one-time fixing.

The use of full-color copying machines, full-color printers, and the like to form full-color images on a transparent substrate such as a sheet for an overhead projector (hereinafter abbreviated as OHP) has been increasing. Today,
Toners used for full-color image formation are required to have various characteristics, for example, stable chargeability and good fluidity, as in the case of the most common conventional black toner,
Transparency, sharpness, color reproducibility and the like are further required.

[0006] Initially, pigments used in ordinary inks and paints have been used as they are as colorants for full-color toners used in full-color copying machines and full-color printers. However, a pigment having sufficiently satisfactory transparency and sharpness was not obtained. Unlike pigments used for toners, pigments used in ordinary inks and paints do not require much transparency and sharpness. There is also a strong demand in the market, and it has been necessary to newly form a pigment which is easy to obtain transparency and clearness when an image is formed, as a colorant for a full-color toner.

[0007] Among the organic pigments, a group of pigments called condensed polycyclics are also called high-grade pigments because of their excellent heat resistance, light resistance and solvent resistance, and various pigments have been used. Is being developed. Under these circumstances, representative pigments developed relatively early include anthraquinone and
Perylene, perinone and the like are known. Subsequently, dioxazine, quinacridone, isoindolinone, etc. were developed,
In recent years, quinophthalones, methine pigments, and the like have been developed.

Among these, isoindolinone and quinophthalone have been developed especially as yellow to orange pigments. Isoindolinone pigments are described in J. Chem. Soc.,
1941, as seen in the 625 there is a first report in 1941. After that, BP833,548, J.Paint Technol.Official D
igest, 37 , 1071, etc., it was used as a pigment in the 1960s. Especially because it is excellent in weather resistance, solvent resistance, heat resistance, resin, fiber coloring,
Widely used in paints and the like. Furthermore, in recent years, there has been a great demand as a substitute for heavy metal-based inorganic pigments. Quinophthalone is a bright yellow compound synthesized by the condensation of quinaldine with phthalic anhydride. Studies have been conducted on this compound to improve the pigment suitability, in particular, the light resistance and the solvent resistance. For example, it has been used as a pigment since the 1970s as shown in JP-B-47-3,476.

Other known condensed polycyclic pigments include pigments such as fluorbin and epindridione. Fluorubin is a compound synthesized for the first time in 1903 as shown in Ber., 36 , 4048. As a pigment, for example, it has excellent light resistance and solvent resistance as shown in JP-B-38-17,831. Also, as reported in Ann. Chem., 518 , 245, quinacridone first synthesized in 1935
As seen in P2,884,484 and USP2,884,485, in 1958 it became widely used as a new red pigment in the printing ink and paint industries. This led to a search for compounds with a structure similar to quinacridone. Epindridione was one of the compounds studied at that time. Epindridione is a structure lacking a central benzene ring in the chemical structure of quinacridone, which corresponds to a structural isomer of indigo. This compound is
M.Soc., are initially synthesized as a 1934, as reported in 1508 2,8 dimethyl substitution product, Helv. Chim. Acta, 3
As seen in 1,716, the maternal skeleton was first synthesized in 1948. The patent for this compound as a pigment is USP
3,334,102 only, in this patent dimethoxy, diethoxy substituted and di, tri, tetrahalogen substituted,
It is described as a pigment having excellent light fastness and coloring power.

Generally, the properties required for pigments include:
Coloring properties such as tinting strength, clarity, hue, light resistance, heat resistance, acid resistance, alkali resistance, solvent resistance, durability such as migration resistance and dispersibility, fluidity etc. Can be Of these required properties, the color properties and durability are properties that directly affect the quality of the pigment and are particularly important. Regarding the condensed polycyclic high-grade pigments described so far, in any of these properties, at present, excellent pigments are very limited,
The appearance of new pigments having excellent properties is expected.

That is, since a full-color image is obtained by superimposing a plurality of color toners on a material to be transferred as described above, if the light transmittance of each toner is insufficient, color reproducibility deteriorates. It is difficult to obtain a clear image. This phenomenon is particularly remarkable when a full-color image is formed on a transparent substrate such as an OHP sheet, and it is difficult to obtain a good transparent image.

As a measure for improving the transparency, it is conceivable to increase the degree of dispersion of the pigment, that is, to reduce the particle size of the pigment in the toner. Generally, as the particle size of the pigment is reduced to increase the degree of dispersion, the transparency of the pigment dispersion is improved.
However, ordinary dispersing machines such as a sand mill, a three-roll mill, a ball mill, and an extruder mainly break only secondary particles (primary particles are weakly agglomerated) of pigment into primary particles. And the like, it is difficult to make the pigment finer. By using a high-speed sand mill or the like, it is possible to further refine the pigment depending on the kind of the pigment, but it requires a very large amount of energy.

As means for refining the primary particles of the pigment,
There is known a method in which a pigment is dissolved in a strong acid such as concentrated sulfuric acid or polyphosphoric acid, and the solution is poured into cold water to precipitate the pigment as fine particles. In this method, the pigments that can be used are significantly limited in terms of solubility and stability of the pigment in strong acids.
In addition, since pigments finely divided by this method cause strong secondary aggregation when dried, it is very difficult to re-disperse the dried pigment to primary particles.Also, as a method for improving dispersibility, alcohol is used. However, it is known that heat treatment is performed in a solvent such as these, but undesired crystal growth occurs and the pigment particle size increases.

As another method, a method is known in which a pigment and a solid resin are heated and kneaded with a two-roll mill or a Banbury mixer while heating. However, since pigments generally grow at high temperatures, in the present method, the end point is reached when the mechanical crushing force and the crystal growth reach an equilibrium state, and there is a limit to the fineness of the pigment.

Further, as a method for finely dividing the primary particles of the pigment, a mixture of the pigment and a water-soluble inorganic salt such as salt is moistened with a small amount of a water-soluble solvent, kneaded strongly with a kneader or the like, and then mixed with the inorganic salt. There is a method in which the solvent is washed away with water and dried to obtain a pigment having fine primary particles. This method is generally known as a pigmentation method of β-type copper phthalocyanine in which crude copper phthalocyanine is mechanically ground in the presence of a water-soluble organic solvent by using salt as a grinding agent. In this case, the water-soluble organic solvent is used as a binder and to prevent the β-type crystal from being crystallized to the α-type crystal due to the mechanical shearing force of the kneader. In general, this method is called solvent salt milling, and is distinguished from a method of simply mechanically reducing the size without using a grinding agent (called dry milling). In a broad sense, salt milling without using a solvent is also called drying.

However, this method has a problem that the pigment tends to undergo strong secondary agglomeration during drying and the particle size of the pigment becomes large.

[0017]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the conventional method and to provide a clear and sufficient color image when a full-color image is formed using a full-color copying machine or printer. An object of the present invention is to provide a yellow toner base particle for developing an electrostatic image capable of obtaining reproducibility and color developing property, and a yellow toner and a yellow developer using the yellow toner base particle.

[0018]

According to the present invention, at least three components of an organic pigment (A) represented by the following general formula (1), a water-soluble inorganic salt (B), and a water-soluble solvent (C) are provided. (B) and (C) are washed with water to obtain a treated pigment (D), which is a yellow toner mother particle for developing an electrostatic image.

General formula (1)

[0020]

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In the formula, R _{1 to} R ₈ each independently represent a hydrogen atom or a halogen atom, and at least three of R _{1 to} R ₄ are halogen atoms.

The second invention provides at least three of the organic pigment (A), the water-soluble inorganic salt (B) and the water-soluble solvent (C) represented by the general formula (1) in the first invention. A yellow toner mother for developing an electrostatic image, formed by mechanically kneading a mixture comprising the components and then using a treated pigment (D) obtained by washing and removing (B) and (C) with water. Particles. However, in the formula, R _{1 to} R ₈ each independently represent a hydrogen atom, a fluorine atom or a chlorine atom,
At least three of R _{1 to} R ₄ are a fluorine atom or a chlorine atom.

According to a third aspect of the present invention, at least three of the organic pigment (A) represented by the general formula (1), the water-soluble inorganic salt (B), and the water-soluble solvent (C) according to the first invention are provided. A yellow toner mother for developing an electrostatic image, formed by mechanically kneading a mixture comprising the components and then using a treated pigment (D) obtained by washing and removing (B) and (C) with water. Particles. Where R ₁ and R ₅ , R ₂ and R
₆ , R ₃ and R ₇ are equal, and R ₄ and R ₈ are equal. Also, R
_{1 to} R ₄ each independently represent a hydrogen atom, a fluorine atom or a chlorine atom, and at least three are a fluorine atom or a chlorine atom.

The fourth invention is characterized in that the water-soluble inorganic salt (B) is used in a weight ratio of 2 to 20 times the water-soluble solvent (C) in the first to third inventions. The yellow toner mother particles for electrostatic image development according to any one of the above.

According to a fifth aspect of the present invention, there is provided a method for developing an electrostatic image, comprising mixing the yellow toner base particles for developing an electrostatic image according to any one of the first to fourth aspects with an external additive. Yellow toner.

According to a sixth aspect of the invention, there is provided a yellow developer comprising a mixture of the yellow toner for developing an electrostatic image according to the fifth aspect of the invention and a carrier.

Examples of the compound represented by the general formula (1) are shown in Table 1 below as exemplary compounds.

[0028]

[Table 1]

[0029]

[0030]

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION Usually, epindridione has the property of being extremely insoluble in organic solvents.
In J. Org. Chem., 33 , 4004 (1968), this property is due to strong intermolecular hydrogen bonding between the oxygen of the carbonyl group in the molecular structure and the hydrogen atom of the imide group in other molecular structures. It has been reported that this intermolecular hydrogen bond is more remarkably observed in the solid state than in the solution state.
In the case of indigo, it is known that, due to intermolecular hydrogen bonding, the solid state transitions to a longer wavelength than the spectrum in a solution. Since the observation results in the case of epidridione are similar to those in the case of indigo, the existence of a similar intermolecular hydrogen bond is presumed.

The feature of the chemical structure of the epindridione pigment used in the present invention is that the benzene ring constituting the molecule has at least three halogen atoms. The introduction of such a halogen atom causes a change in the intermolecular force of the epindridione, and as a result, it is possible to obtain a pigment having properties balanced with respect to the color and various properties.

The method for producing the epidindridione pigment used in the present invention differs depending on whether the chemical structure of the pigment is symmetric or asymmetric. In the case of a symmetrical chemical structure, it can be produced from a four-stage process of esterification of dihydroxyfumaric acid, dehydration condensation with a halogenated aniline, followed by a two-stage condensed cyclization process. In the case of an asymmetric chemical structure, it can be manufactured by the following method. First, an oxalacetic acid diester substituted with a halogenated phenylamino group is synthesized from an ester of glycine substituted with a nitrogen atom with a halogenated phenyl group and an oxalic acid diester. Next, by reacting with a halogenated aniline, a mixture of maleic acid and fumaric acid diester in which adjacent carbon atoms are substituted with different halogenated phenylamino groups is synthesized. As in the case of the symmetric structure described above, this mixture can be subjected to a two-stage condensed cyclization step to produce an epindridione pigment.

The epidridione pigment used in the present invention has a characteristic that it is easy to obtain transparency and clearness when used as a colorant for a toner for developing a full-color electrostatic image, in particular, a colorant. Further, in the present invention, by carrying out the solvent salt milling of such an epindrizione pigment, it is possible to obtain an image which is more transparent and excellent in clarity than ever before. For example,
The organic pigment (A) and the water-soluble inorganic salt (B) are used as crushing aids, and the water-soluble solvent (C) is added in a small amount as a wetting agent. It shall be smaller than before. Thereafter, the mixture is poured into water and stirred with a high-speed mixer or the like to form a slurry. Next, filtration and washing of the slurry are repeated to remove the water-soluble inorganic salt (B) and the water-soluble solvent (C).

By this method, an aqueous paste of the treated pigment is obtained. This is dried and pulverized and used as a colorant for a toner for developing an electrostatic image.

The water-soluble inorganic salt (B) used in the present invention
Examples thereof include salt, potassium chloride and the like.

The water-soluble solvent (C) used in the present invention
The solvent is not particularly limited as long as it is water-soluble. However, a solvent having a high boiling point is preferred from the viewpoint of safety because the temperature rises during salt milling and the solvent is easily evaporated. Examples include 2- (methoxymethoxy) ethanol, 2-butoxyethanol, 2- (isopentyloxy) ethanol, 2- (hexyloxy) ethanol, diethylene glycol, diethylene glycol monomethyl ether,
Diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, liquid polyethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-ethoxy-2-propanol, dipropylene glycol , Dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, low molecular weight polypropylene glycol, and the like.

In addition to the above compounds, additives such as a dispersant and a plasticizer may be used in combination during salt milling.

In the present invention, a resin may be added as needed when kneading mechanically. The type of resin used is not particularly limited, and natural resins, modified natural resins, synthetic resins, synthetic resins modified with natural resins, and the like can be used. The resin used is preferably solid at room temperature, insoluble in water, and, when a solvent is used during kneading, more preferably partially soluble in the solvent. Further, a pigment derivative and a dispersant may be added.

The particle size of the pigment at the end of the salt milling is preferably 0.2 μm or less, more preferably 0.1 μm, based on the average particle size determined by a laser scattering method.
It is known that, when an image is formed with such a particle size, clear and sufficient color reproducibility and color developing property can be easily obtained.

The yellow toner base particles of the present invention can be obtained according to a conventional method. That is, a binder resin and, if necessary, other charge control agents and additives are added to the above-mentioned treated pigment (D), preliminarily mixed with a Henschel mixer or the like, and then melt-kneaded using an extruder or the like. Next, after cooling, the mixture is roughly pulverized by a hammer mill or the like, finely pulverized by a jet mill or the like, and classified by an air classifier or the like to obtain a classified product having a predetermined particle size distribution with an average particle size of about 5 to 20 μm.

As the binder resin, widely used ones including known ones can be used. In consideration of image transparency, a colorless and transparent resin is more preferable. For example, polystyrene, styrene-acrylate copolymer, styrene-butadiene copolymer, chloride resin, styrene-vinyl acetate copolymer, rosin-modified maleic acid resin, phenol resin, epoxy resin, polyester resin, low molecular weight polyethylene, Molecular weight polypropylene, ionomer resin,
Examples include polyurethane resin, silicone resin, rosin / ester, and rosin. The production method of any resin is not particularly limited.

It is also preferable to add a charge control agent to the yellow toner base particles of the present invention. As charge control agents,
All known types of positive and negative charges can be used, but a colorless or light-colored charge control agent that does not affect the color tone of an image is preferable. For example, an organic metal complex such as a metal complex of an alkyl-substituted salicylic acid (for example, a chromium complex, an aluminum complex, or a zinc complex of di-tert-butylsalicylic acid) can be given.

It is also preferable to mix various particles as external additives in the yellow toner base particles of the present invention as a fluidity improver, a cleaning aid and the like. Any known external additives can be used. For example, 0.01-0.5μ
m, silica, alumina, metal oxides such as titanium oxide, silicon carbide, abrasives such as tungsten carbide, zinc stearate, lubricants such as fatty acid metal salts such as aluminum stearate, and other 1 to 50 μm polytetrafluoroethylene;
It is preferable to add a fine powder such as polyvinylidene fluoride, polymethyl methacrylate, polystyrene, or silicone. It is also preferable to add an external additive obtained by variously surface-treating these mixtures and further, these fine powders.

The yellow developer of the present invention is a mixture of the above yellow toner and a carrier, and can be obtained by a conventionally known method, and is not particularly limited. As the carrier used for the yellow developer according to the present invention, all known carriers can be used. In general, carriers constituting a two-component developer are roughly classified into conductive carriers and insulating carriers. Normally, oxidized or unoxidized iron powder is used as the conductive carrier.
A typical example of the insulating carrier is a carrier in which the surface of a carrier core material particle generally made of a ferromagnetic material is uniformly coated with an insulating resin. Carrier as core material,
For example, particles of iron oxide (magnetite), reduced iron, copper, ferrite, nickel, cobalt, and the like, and alloys of zinc, aluminum, and the like can be used. As the coating resin, any of known materials such as acrylic resin, epoxy resin, silicone resin, urethane resin, polyacetal resin, polyamide resin, polycarbonate resin, phenol resin, vinyl acetate resin, cellulose resin, polyolefin resin, fluorine resin, amino resin, etc. It may be. The carrier preferably has a particle size of about 20 to 200 μm. Generally, the developer contains 1 to 1 toner.
It is preferable to contain 30%.

[0046]

The present invention will be described below in more detail with reference to Examples and Comparative Examples. However, this does not limit the embodiment of the present invention at all. In Examples and Comparative Examples, parts and% indicate parts by weight and% by weight, respectively.

Example 1 [Synthesis Step of Epindridione Pigment] 44.4 parts of dihydroxyfumaric acid was dissolved in 190 parts of methanol, and 60 parts of anhydrous magnesium sulfate was added to this solution. The suspension is cooled to 0-5 ° C. and hydrogen chloride is bubbled in at this temperature for 4.5 hours with stirring. Next, this liquid is allowed to stand at room temperature for 3 days, and then the precipitated crystals are filtered. The crystals obtained are washed with a small amount of methanol, suspended in 600 parts of cold water and then quickly filtered. Further, the crystals were washed with cold water until the washing liquid became neutral, and dried at 70 ° C. to obtain 45.3 parts of an ester having the following structure.

[0048]

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Next, after suspending 44.0 parts of the above ester in 158 parts of methanol, 2,3,4-
80.9 parts of trifluoroaniline and 3 parts of concentrated hydrochloric acid are added, and the mixture is heated under reflux for 6 hours. During the heating, the reaction solution once becomes a solution, and then pale yellow crystals precipitate. After the reaction solution was cooled to 5 to 10 ° C., the precipitated crystals were filtered and dried at 70 ° C. to obtain 94.7 parts of a compound having the following structure.

[0050]

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86.8 parts of the above compound was added to Dowtherm A868
The suspension added in the solution was heated to 120 to 130 ° C. to form a solution, and the solution was heated under reflux to Dowtherm A347.
Add to parts over 30 minutes. Then, reflux heating was performed for 1 while removing the mixture of Dowtherm A and the generated methanol.
Perform for 5 minutes and cool to room temperature. The precipitated crystals were washed with petroleum ether and dried at 70 ° C. to obtain 61.9 parts of a compound having the following structure.

[0052]

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60.3 parts of the above compound are added to 603 parts of polyphosphoric acid with stirring. The mixture is added for 15 hours in one hour.
After heating to 0 ° C, it is heated at 145 to 150 ° C for 2 hours and then cooled to 40 to 50 ° C. Next, 1340 parts of methanol are gradually added while maintaining 40 to 50 ° C. After the addition is completed, the mixture is heated under reflux for 90 minutes and filtered. The solution was washed with water until the washing solution became neutral, and dried to obtain 50.0 parts of a pigment represented by Compound No. 1 in Table 1.

[Salt milling step] The above pigment: 250
Parts, 2500 parts of sodium chloride and 160 parts of polyethylene glycol 300 (manufactured by Tokyo Chemical Industry Co., Ltd.) were charged into a stainless steel 1 gallon kneader (manufactured by Inoue Seisakusho) and kneaded for 3 hours. Next, this mixture was poured into 2.5 liters of warm water and stirred for about 1 hour with a high speed mixer while heating to about 80 ° C. to form a slurry. Thereafter, filtration and washing were repeated 5 times to remove the sodium chloride and the solvent to obtain an aqueous pigment dispersion having a solid content of 50%. It is further dried and pulverized and used as a colorant for toner.

[Toner Forming Step] The above colorants for toner 3.0 parts Unsaturated polyester resin 100.0 parts Negative charge control agent 3.0 parts
Melt and knead with a twin-screw extruder. After cooling, the mixture is roughly pulverized using a hammer mill and finely pulverized using a jet mill, and then toner base particles having an average particle diameter of 10.0 μm are obtained using an air classifier. 0.4 parts of titanium oxide fine powder was added to 100 parts of the toner base particles and mixed with a Henschel mixer to obtain a toner.

[Toner Evaluation Step] 6 parts of the obtained toner was added to 100 parts of ferrite and mixed with a ball mill to obtain a developer. Using this developer, an image was formed with a commercially available full-color copying machine (CLC350, manufactured by Canon) and evaluated.

Example 2 [Synthesis Step of Epindridione Pigment] 44.0 parts of the methyl ester of dihydroxyfumaric acid described in Example 1 were suspended in 158 parts of methanol, and the suspension was added with 2,2 parts.
108.1 parts of 4,5-trichloroaniline and concentrated hydrochloric acid 3
And heating at reflux for 6 hours. During the heating, the reaction solution once becomes a solution, and then pale yellow crystals precipitate. After cooling the reaction solution to 5 to 10 ° C., the precipitated crystals were filtered, and
By drying at 0 ° C., compound 109.
One part was obtained.

[0058]

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The above compound (106.4 parts) was added to Dowtherm A10
The suspension added in 64 parts was heated to 120 to 130 ° C. to form a solution, and this solution was heated under reflux to Dowtherm A4.
Add to 25 parts over 30 minutes. Then Dowtherm A
The mixture is refluxed and heated for 15 minutes while removing a mixed solution of and formed methanol, and cooled to room temperature. The precipitated crystals were washed with petroleum ether and dried at 70 ° C. to obtain 82.3 parts of a compound having the following structure.

[0060]

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75.0 parts of the above compound are added to 750 parts of polyphosphoric acid with stirring. The mixture is added for 15 hours in one hour.
After heating to 0 ° C., it is heated at 145 to 150 ° C. for 2 hours, and then cooled to 40 to 50 ° C. Next, 1660 parts of methanol are gradually added while maintaining 40 to 50 ° C. After the addition is completed, the mixture is heated under reflux for 90 minutes and filtered. Washing was carried out with water until the washing liquid became neutral, and dried to obtain 62.3 parts of a pigment represented by Compound No. 2 in Table 1. Using this pigment, toner base particles, a toner and a developer were obtained in the same manner as in Example 1, and the evaluation was performed in the same manner.

Example 3 [Synthesis Step of Epindridione Pigment]
In 9 parts are added, with stirring, 14.3 parts of sodium ethoxide. After the sodium ethoxide has completely dissolved,
At room temperature, 29.2 parts of diethyl oxalate and N-
Add 49.6 parts of (3,4-dichlorophenyl) glycine ethyl ester and stir at 25 ° C. for 20 hours. Next, ethanol is distilled off under reduced pressure, 150 parts of water and 15 parts of acetic acid are added, and the mixture is vigorously stirred. Further toluene 10
After adding 4 parts, stirring a little, and allowing to stand at room temperature, the reaction solution separates into an oil layer and an aqueous layer. The aqueous layer is separated, extracted twice with 35 parts of toluene, the extract is mixed with the oil layer and filtered. The filtrate was washed with 120 parts of water, and toluene was removed by distillation under reduced pressure to give Compound 5 having the following structure.
8.4 parts were obtained.

[0063]

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52.2 parts of the above compound, 29.6 parts of 2,4,5-trichloroaniline and 1.8 parts of concentrated hydrochloric acid are heated under reflux for 3 hours in 101 parts of ethanol. Next, after removing 61 parts of ethanol by distillation under reduced pressure, the precipitated crystal was filtered and washed with 16 parts of ethanol.
To obtain 48.2 parts of a mixture composed of compounds having the following two structures.

[0065]

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[0066]

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The above compound (47.4 parts) was added to Dowtherm A474.
The suspension added in the mixture was heated to 120 to 130 ° C. to form a solution, and the solution was heated under reflux to Dowtherm A190.
Add to parts over 30 minutes. Then, reflux heating was performed for 1 while removing the mixture of Dowtherm A and the generated methanol.
Perform for 5 minutes and cool to room temperature. The precipitated crystals were washed with petroleum ether and dried at 70 ° C. to obtain 36.3 parts of a compound having the following structure.

[0068]

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33.6 parts of the above compound are added to 336 parts of polyphosphoric acid with stirring. The mixture is added for 15 hours in one hour.
After heating to 0 ° C., it is heated at 145 to 150 ° C. for 2 hours, and then cooled to 40 to 50 ° C. Next, 747 parts of methanol are gradually added while maintaining the temperature at 40 to 50 ° C. After the addition is completed, the mixture is heated under reflux for 90 minutes and filtered. The resultant was washed with water until the washing liquid became neutral, and dried to obtain 27.2 parts of a pigment represented by Compound No. 3 in Table 1. Using this pigment, toner base particles, a toner and a developer were obtained in the same manner as in Example 1, and the evaluation was performed in the same manner.

Comparative Examples 1 to 3 In the comparative examples, the pigments represented by Compound No. 1 in Table 1, in Comparative Example 2, Compound No. 2 in Table 1 and in Comparative Example 3, the pigments represented by Compound No. 3 in Table 1 were subjected to a salt milling step. The toner base particles, the toner, and the developer were obtained as described below, and evaluated in the same manner.

[Toner Forming Step] Pigment (not subjected to the salt milling step) 3.0 parts Unsaturated polyester resin (same as in Example 1) 100.0 parts Negative charge control agent 3.0 parts Premix with a Henschel mixer,
Melt and knead with a twin-screw extruder. After cooling, the mixture is roughly pulverized using a hammer mill and finely pulverized using a jet mill, and then toner base particles having an average particle diameter of 10.0 μm are obtained using an air classifier. 0.4 parts of titanium oxide fine powder was added to 100 parts of the toner base particles and mixed with a Henschel mixer to obtain a toner.

Examples 1 to 3 are examples after the salt milling step. The image had a high saturation and a clear image was obtained. Also, a clear image was obtained for the intermediate colors using the toners of the individual colors. When an image is formed on an OHP sheet,
Considerable transparency was obtained, and the effect of salt milling was confirmed.

In Comparative Examples 1 to 3, toners were formed by the same combination using the pigment and resin used in Examples 1 to 3 by a usual production method. That is, toner base particles and the like were formed in a normal process without performing salt milling. Comparative Examples 1 and 2
Sample No. 3 did not provide clear and sufficient color reproducibility and color developability, and the difference was clear when comparing the images of Example 1 and Comparative Example 1 using the same pigment.

[0074]

According to the present invention, fine and sufficient color reproducibility and color development can be obtained by using an epindridione pigment finely divided by salt milling as a colorant for toner base particles. When the dispersion state of the pigment was observed with an optical microscope, it was confirmed that the dispersion state was very good without aggregation.

Claims (6)

[Claims] 1. An organic pigment (A) represented by the following general formula (1), a water-soluble inorganic salt (B), and a water-soluble solvent (C)
Characterized in that it contains a treated pigment (D) obtained by mechanically kneading a mixture comprising at least three components of the following, and then removing (B) and (C) by washing with water. Mother particles. General formula (1) However, in the formula, R _{1 to} R ₈ each independently represent a hydrogen atom or a halogen atom, and at least three of R _{1 to} R ₄ are halogen atoms. 2. A mixture comprising at least three components of the organic pigment (A) represented by the general formula (1), the water-soluble inorganic salt (B), and the water-soluble solvent (C) according to claim 1. Yellow toner mother particles for electrostatic image development, formed by using a treated pigment (D) obtained by mechanically kneading and then removing (B) and (C) with water. However, in the formula, R _{1 to} R ₈ each independently represent a hydrogen atom, a fluorine atom or a chlorine atom, and at least three of R _{1 to} R ₄ are a fluorine atom or a chlorine atom. 3. A mixture comprising at least three components of the organic pigment (A) represented by the general formula (1), the water-soluble inorganic salt (B), and the water-soluble solvent (C) according to claim 1. Yellow toner mother particles for electrostatic image development, formed by using a treated pigment (D) obtained by mechanically kneading and then removing (B) and (C) with water. Where R ₁ and R ₅ , R ₂ and R ₆ , R ₃ and R ₇ , R ₄ and R ₈
Are equal to each other. R _{1 to} R ₄ each independently represent a hydrogen atom, a fluorine atom or a chlorine atom, and at least three are a fluorine atom or a chlorine atom. 4. The electrostatic charge according to claim 1, wherein the weight ratio of the water-soluble inorganic salt (B) to the water-soluble solvent (C) is 2 to 20 times. Yellow toner base particles for image development. 5. A yellow toner for developing an electrostatic charge image, comprising a mixture of the yellow toner base particles for developing an electrostatic charge image according to claim 1 and an external additive. 6. A yellow developer comprising a mixture of the yellow toner for developing an electrostatic image according to claim 5 and a carrier.