JPH117159A - Electrostatic charge image developing color toner and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrostatic charge image developing color toner having not only coloring property, sharpness and transparency but excellent light resistance by incorporating a binder resin and a coloring agent containing a particulate org. pigment and a specified proportion of particulate barium sulfate to the pigment. SOLUTION: The electrostatic charge image developing color toner contains a binder resin and a coloring agent containing 100 pts.wt. of particulate org. pigment and 1 to 150 pts.wt. of particulate barium sulfate. Namely, by incorporating the particulate barium sulfate as well as the particulate org. pigment, excellent sharpness of an image is obtd. when the image is fixed to a transfer material with the toner. The particle size of the particulate org. pigment is preferably 0.01 to 0.5 μm, more preferably 0.01 to 0.2 μm, considering the color developing property and transparency of the image to be formed. The particle size of the particulate barium sulfate is preferably 0.001 to 0.1 μm, and more preferably 0.001 to 0.6 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color toner for developing an electrostatic image used for developing an electrostatic latent image in electrophotography, electrostatic recording, and electrostatic printing, and a method for producing the same.

[0002]

2. Description of the Related Art It is well known that an image is formed on a photoconductor by using static electricity. For example, various methods of electrophotography, such as U.S. Pat. No. 2,297,691 and Japanese Patent Publication No. 42-23910, are known, and a photoconductive material is used on a photoreceptor by various means. An electrostatic latent image is formed on the toner image, the latent image is developed with a developer, and the toner powder image is transferred to a transfer material such as paper. Get. Then, a cleaning step (or mechanism) for removing the developer remaining on the photoconductor is usually provided. A developing method for visualizing an electrostatic latent image is described, for example, in US Pat.
The magnetic brush method described in 874,063, the cascade developing method described in 2,618,522, and the method using a conductive magnetic developer described in 3,909,258 are known. ing.

Conventionally, fine powders of a natural or synthetic resin in which a dye or pigment is dispersed have been used as a toner applied to these developing methods. For example, one obtained by dispersing a colorant in a binder resin such as polyester is 1-2.
Particles pulverized to about 0 μm are used as toner. A so-called two-component developer obtained by mixing the toner and carrier particles such as iron powder is also used.
In recent years, such recording methods have been widely used not only for general copying machines but also for computer outputs, so that the required performance has become higher, and colorization, miniaturization, weight reduction, and low energy consumption have been required. Various demands have been made, such as making the system free and maintenance-free. Especially,
For color toners, in addition to clarity, coloring, and transparency, color toners are also required to have general-purpose uses, such as calendars, posters, and marking materials, and thus require light fastness and the like. It has become.

Conventionally, it has been known that the coloring property, the sharpness, and the transparency are generally improved by decreasing the particle size of the pigment and increasing the degree of dispersion. In a normal dispersing machine such as a ball mill, when the primary particles are dispersed, the coloring property and the like cannot be further improved. This is because the dispersion process using a usual dispersing machine mainly mainly breaks down the secondary particles into primary particles, and it is necessary to make the primary particles themselves finer in order to further improve the colorability and the like.

As a means for making the primary particles themselves fine, there is known a method in which a pigment dissolved in a strong acid such as concentrated sulfuric acid or polyphosphoric acid is poured into cold water to precipitate the pigment as fine particles. The pigments that can be used are markedly limited in view of the solubility and stability of the pigment in strong acids. For example, Japanese Patent Publication No. 7-27282 proposes a method of obtaining a blue toner by using a phthalocyanine pigment precipitated by an acid paste method or the like. However, even if fine primary particles are obtained, the pigment is contained in the binder resin. In the process of dispersing the toner, the primary particle pigment causes strong secondary agglomeration due to the use of a solvent or heating to a high temperature, so it is difficult to re-disperse the primary particles in the toner again, which is satisfactory in terms of transparency and the like. Not something you can do.

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 being heated. However, since organic pigments generally grow at high temperatures, there is a limit to finer pigments.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a color toner for developing an electrostatic charge image which is excellent in light resistance in addition to coloring property, sharpness and transparency.

[0008]

According to a first aspect of the present invention, there is provided a colorant (A) containing 1 to 150 parts by weight of fine barium sulfate (a2) based on 100 parts by weight of fine organic pigment (a1) and a binder resin. (B) is a color toner for developing electrostatic images.

In a second aspect, the colorant (A) is used in an amount of 0.1 to 1%.
The color toner for developing an electrostatic image according to the first invention, which is contained in an amount of 5% by weight.

According to a third aspect of the present invention, the fine particle organic pigment (a1) has a particle diameter of 0.01 to 0.5 μm, and the fine particle barium sulfate (a2) has a particle diameter of 0.001 to 0.1 μm. A color toner for developing an electrostatic image according to the first or second aspect of the invention.

A fourth invention is directed to a fine-particle organic pigment (a1)
Is at least one member selected from the group consisting of quinacridone, phthalocyanine, azo, isoindolinone, dianthraquinonyl red, sulene, and perylene-based. A color toner for developing an electrostatic image according to any one of the third aspect of the present invention.

In a fifth aspect of the present invention, an organic pigment, a water-soluble inorganic salt, barium sulfate and a water-soluble solvent are mechanically mixed and then washed with water to remove the water-soluble inorganic salt and the water-soluble solvent. A colorant (A) containing a finely divided organic pigment (a1) and a finely divided barium sulfate (a2), and a binder resin (B) are melt-kneaded, and a color for electrostatic image development is provided. This is a method for producing a toner.

In a sixth aspect of the present invention, a mixture of fine organic pigment (a1), fine barium sulfate (a2) and water obtained by removing a water-soluble inorganic salt and a water-soluble solvent is mechanically mixed with a resin for dispersion. The color for developing an electrostatic image according to the fifth aspect of the present invention, wherein the colorant (A2) obtained by kneading using a shearing force to remove water and the binder resin (B) are melt-kneaded. This is a method for producing a toner.

According to a seventh aspect of the present invention, the fine particle organic pigment (a1) has a particle size of 0.01 to 0.5 μm, and the fine particle barium sulfate (a2) has a particle size of 0.001 to 0.1 μm. A method for producing a color toner for developing an electrostatic image according to the fifth or sixth aspect of the invention.

According to an eighth aspect of the present invention, there is provided the electrostatic charge according to any one of the fifth to seventh aspects, wherein a water-soluble inorganic salt is used in a weight ratio of 2 to 20 times the water-soluble solvent. This is a method for producing a color toner for image development.

The ninth invention is directed to a fine-particle organic pigment (a1)
Is at least one member selected from the group consisting of quinacridones, phthalocyanines, azos, isoindolinones, diansuraquinonyl reds, sulenes, and perylenes. A method for producing a color toner for developing electrostatic images according to any one of the eighth aspect of the present invention.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The color toner for developing an electrostatic image of the present invention is characterized by containing a particulate organic pigment (a1) and a particulate barium sulfate (a2). By containing the fine barium sulfate (a2) in addition to the fine organic pigment (a1), the image is excellent in sharpness when the toner is fixed on the transfer material. The particle size of the finely divided organic pigment (a1) used in the present invention is preferably from 0.01 to 0.5 μm, more preferably from 0.01 to 0.2 μm, from the viewpoint of the color developability and transparency of the obtained image. It is preferable that the particle diameter of the fine barium sulfate (a2) is 0.0
It is preferably from 0.1 to 0.1 μm, more preferably from 0.0 to 0.1 μm.
It is preferably from 01 to 0.6 μm.

The coloring agent (A) containing the fine organic pigment (a1) and the barium sulfate (a2) uses an inorganic salt as a crushing aid, and mechanically fines the primary particles of the organic pigment (this step is referred to as a "coloring agent"). The use of barium sulfate together in the step) prevents aggregation of the organic pigment fine particles in the binder resin and ensures a more finely dispersed state. Compared to using pigments,
This makes it possible to obtain an image having excellent sharpness and transparency.

The specific method of salt milling using barium sulfate in the present invention will be described below. 100 parts by weight of organic pigment and barium sulfate 1-150
Add a small amount of a water-soluble solvent to a mixture of a water-soluble inorganic salt to 5 parts by weight, preferably 5 to 120 parts by weight, and knead the mixture with a kneader or the like. The water-soluble inorganic salt and the water-soluble solvent are dissolved into water to form a slurry. next,
The slurry is repeatedly filtered and washed with water to remove the inorganic salt and the solvent to obtain an aqueous dispersion of a mixture of the particulate organic pigment (a1) and the particulate barium sulfate (a1). If the amount of the fine barium sulfate is less than 1 part by weight with respect to 100 parts by weight of the organic pigment in the above step, the obtained fine organic pigment (a1) and the fine barium sulfate (a1) are used as a colorant (A) for the toner. Does not improve image clarity,
On the other hand, when the amount exceeds 150 parts by weight, the coloring property is adversely affected,
The sharpness of the image decreases.

The water-soluble inorganic salt used for the salt milling treatment in the present invention includes salt, potassium chloride,
Glauber salt and the like. The amount of the water-soluble inorganic salt used is 2 to 20 times, more preferably 3 to 15 times the weight ratio of the water-soluble solvent.

The water-soluble solvent used for the salt milling treatment in the present invention is not particularly limited as long as it is water-soluble, but it is preferable to use a solvent having a high boiling point in order to make the solvent difficult to evaporate. The water-soluble solvent is added for a binder and an effect of preventing crystallization. For example, 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 are used. The amount of the water-soluble solvent used is preferably 2 to 10 times the weight ratio of the organic pigment to be treated.

In the present invention, as the organic pigment to be subjected to the salt milling treatment, it is preferable to use an organic pigment having a lower hardness than the inorganic salt of the crushing aid. As an example of an organic pigment, a color index (CI) number indicates that the phthalocyanine-based pigment is C.I. I. Pigment Blue 15, 1
5: 1, 15: 2, 15: 3, 15: 4, 15: 6,
C. I. Pigment Green 7, 36, and C.I. I. Pigment Blue 60 and 64, and dioxazines such as C.I. I. Pigment Violet 23, 3
7, C.I. I. Pigment Yellow 1,
2, 3, 5, 6, 10, 12, 13, 14, 17, 4,
9, 55, 60, 61, 62: 1, 63, 65, 73,
74, 75, 81, 83, 87, 90, 93, 94, 9
5, 97, 98, 106, 111, 113, 114, 1
16, 121, 124, 126, 127, 128, 13
0, 136, 152, 165, 166, 167, 17
0, 171, 172, 174, 176, 188, C.I.
I. Pigment Orange 1, 6, 13, 15, 16, 3
1, 34, 64, C.I. I. Pigment Red 37, 3
8, 41, 48: 1, 48: 2, 48: 3, 48: 4,
48: 5, 57: 1, 58: 2, 58: 4, 63: 1,
63: 2, 64, 64: 1, 111, 144, 166,
214, 220, 221, 242, 248, 262,
C. I. Pigment Brown 23, 41, 42 and quinacridones include C.I. I. Pigment Orange 48, 4
9, C.I. I. Pigment Red 122, 192, 20
2, 206, 207, 209, C.I. I. Pigment Violet 19, 42, and naphthols include C.I. I.
Pigment Orange 2, 5, 22, 24, 38, 46,
C. I. Pigment Red 1, 2, 3, 4, 5, 6,
7, 8, 9, 10, 11, 12, 13, 14, 15, 1,
6, 17, 18, 21, 22, 23, 31, 32, 4,
9, 49: 1, 49: 2, 49: 3, 50: 1, 51:
1,53,53: 1,60: 1,66,67,68,9
5, 112, 114, 119, 136, 146, 14
7, 148, 150, 151, 164, 170, 18
4,187,188,210,212,213,22
2,223,237,243,245,247,24
7: 1, 253, 256, 258, 261; I. Pigment Violet 13, 25, 44, 50, C.I.
I. Pigment Brown 1 and C.I.
I. Pigment Red 123, 149, 178, 17
9, 190, 224, C.I. I. Pigment Violet 29, C.I. I. Pigment Blacks 31, 32, and diketopyrrolopyrroles include C.I. I. Pigment Red 254, 255 and isoindolinone-based pigments include C.I. I.
Pigment Yellow 109, 110, 173 and benzimidazolones include C.I. I. Pigment Yellow 12
0, 151, 154, 175, 180, 181, 19
4, C.I. I. Pigment Orange 36, 60, 62,
C. I. Pigment Red 175, 176, 185, 2
08, C.I. I. Pigment Violet 32, C.I. I.
Pigment Brown 25 and quinophthalone-based
C. I. Pigment Yellow 138 and anthraquinone-based pigments such as C.I. I. Pigment Yellow 123, 147,
193, C.I. I. Pigment Red 89, 168, 17
7, C.I. I. Pigment Violet 5: 1, C.I. I.
Pigment Black 20 and the like. The organic pigment to be subjected to the salt milling treatment may be either in a wet state sufficiently washed with water after the pigment synthesis reaction or in a dry state commercialized. Further, a surface-treated pigment obtained by adding a functional group to the surface of the pigment may be used.

In the present invention, an aqueous dispersion of a mixture of a fine organic pigment (a1) and a fine barium sulfate (a2) (hereinafter referred to as a mixture) which has been subjected to a salt milling treatment using barium sulfate in combination as described above. May be used as a powder pigment by washing and drying as usual, or a toner may be obtained by kneading an aqueous dispersion of the above mixture subjected to salt milling with a binder resin for a toner described below. Alternatively, the aqueous dispersion of the mixture is kneaded by applying mechanical shearing force together with the resin for dispersion and the mixture is transferred to the resin for dispersion, and water is removed to obtain a resin dispersion of the mixture. The toner may be obtained by kneading the resin dispersion of the mixture as a coloring agent together with a binder resin for a toner described later, and the third method is most preferable in that the pigment is hardly aggregated.

In the case of the third method, as a colorant, that is, a dispersing resin used for obtaining a resin dispersion of a mixture, the same resin as a binder resin described later may be used. A series of resins may be used. When a resin of a different system from the binder resin is used, it is preferable to use a resin having high compatibility with the binder resin in order to highly disperse the pigment. Such a method is preferably performed under heating in order to ensure the affinity between the resin for dispersion and the treated organic pigment. Therefore, if an organic solvent is also used, the heating temperature is set so that the solvent is not easily evaporated. Is preferably equal to or lower than the boiling point of the organic solvent used. This is because if the solvent evaporates due to heat, the pigment fine particles agglomerate, resulting in poor transparency and coloring.
However, it is preferable to use only water from the viewpoint of energy cost and environmental conservation without requiring an organic solvent recovery step.

When obtaining the colorant (A) in the present invention, a phthalocyanine pigment derivative, a dispersant such as a polymer type dispersant, and an additive such as a plasticizer may be used in combination. An aqueous dispersion of an organic pigment may be mixed and treated.

As a device for applying a mechanical shearing force in the process of obtaining the colorant (A) in the present invention, in addition to the above kneader, a high-speed rotation represented by a pressure kneader, a three roll, an extruder and a Henschel mixer. Mixing / kneading mixer having a plurality of stirring blades or the like.

In the process of obtaining the colorant (A) in the present invention, the method of removing water after transferring the mixture to a resin for dispersion includes a general drying method and, if necessary, a three-roll method. Etc. may be used.

In the present invention, the colorant (A) and the binder resin (B) obtained as described above are melt-kneaded while heating,
After cooling, pulverize or knead the mixture of the mixture and water together with the resin for dispersion by applying mechanical shearing force, transfer the mixture to the resin for dispersion, and remove the water to obtain a color. This is a method for producing a color toner for developing an electrostatic image, which comprises melting and kneading the agent (A1) and the binder resin (B) while heating, cooling, and then pulverizing the same. The latter method is preferred. In the toner particles, the finely divided organic pigment (a1) obtained as described above is 1 to 1
It is preferable to contain 0% by weight. When the amount is less than the above range, the image density is reduced, and when the amount is more than the above range, the chargeability is reduced and fog is caused.

The binder resin used in the present invention is a resin having good fixability and excellent transparency, such as polyester, acrylic, styrene-acrylic and epoxy resins. More preferably, among these, non-linear resins, particularly preferably a polyester resin, a bisphenol derivative represented by a bisphenol A-alkylene oxide adduct or a substituted product thereof alone as a diol component, or Used in combination with an aliphatic dialcohol, those obtained by condensation or co-condensation of these diol components and carboxylic acids having a valency of 2 or more, such as fumaric acid, terephthalic acid, and trimellitic acid, are preferably used. Can be

In the present invention, the melt-kneading temperature of the colorant (A) and the binder resin (B) or the melt-kneading temperature of the colorant (A1) and the binder resin (B) is preferably 100 to 140 ° C. And more preferably 110 to 130 ° C. By mixing in the above range, the colorability of the toner and the like are improved. In the present invention, when the colorant (A) and the like and the binder resin (B) are melt-kneaded, a known charge control agent such as a metal salt of a salicylic acid derivative or a polymer type quaternary ammonium salt is contained. And waxes may be added internally. Further, an external additive such as a cleaning aid or a transfer aid such as a fluidizing agent for hydrophobized metal oxide (alumina, titania, silica) or a fine powder of a polymer (polystyrene, polymethacrylate, polyvinylidene fluoride, etc.) is used. You can also.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. In the examples, "parts" indicates parts by weight. [Example 1] Crude copper phthalocyanine (copper phthalocyanine manufactured by Toyo Ink): 250 parts, sodium chloride: 250
0 parts, 250 parts of BF-1 (Barium sulfate manufactured by Sakai Chemical)
Parts and 200 parts of diethylene glycol (manufactured by Tokyo Chemical Industry) were charged into a stainless 1 gallon kneader (manufactured by Inoue Seisakusho) and kneaded for 3 hours. Next, the mixture was poured into 2.5 liters of warm water, heated to about 80 ° C., and stirred.
After stirring for about 1 hour to form a slurry, filtration and washing with water were performed for 5 hours.
The aqueous pigment dispersion (treated pigment dispersion) having a solid content of 50% was obtained by repeating the process to remove the sodium chloride and the solvent.
When the obtained aqueous pigment dispersion was observed with a transmission electron microscope, the particle size of copper phthalocyanine was 0.11 μm.
m, the particle diameter of barium sulfate was 0.05 μm.

(Production Method of Cyan Colorant (A1)) The above organic pigment (treated pigment dispersion, solid content 50% product) 100 parts Linear polyester resin 50 parts Polymer type dispersant 2.5 parts Supermixer (Kawata) The above raw materials are mixed in 9
The mixture was heated and kneaded at 0 ° C to remove water, cooled, and then pulverized to prepare a cyan colorant.

(Production Method of Cyan Toner) Non-linear polyester resin 100 parts Cyan colorant 5 parts The above materials were mixed with a Henschel mixer (Mitsui Mining),
The mixture was melt-kneaded with an extruder, pulverized and classified to obtain parent cyan toner particles A having a volume average particle size of 8.5 μm. Next, 0.6 parts by weight of the hydrophobized anatase-type barium sulfate fine particles were added to 100 parts by weight of the parent cyan toner particles A to obtain a cyan toner.

(Adjustment of Cyan Developer) An average particle diameter of 50 μm obtained by coating 5 parts of the above cyan toner with a silicone resin is used.
A color developer was prepared by mixing 95 parts of a m ferrite carrier.

Example 2 In place of the crude copper phthalocyanine of Example 1, an aqueous pigment dispersion was prepared in the same manner as in Example 1 except that 260 parts of a yellow pigment (Hoster Palm Yellow H3G, manufactured by Hoechst) was used. Colorant,
A mother yellow toner, a yellow toner and a yellow developer were obtained.

Example 3 An aqueous pigment dispersion, red in the same manner as in Example 1 except that 250 parts of a red pigment (Hoster Palm Pink E: quinacridone type, Hoechst) was used instead of the crude copper phthalocyanine of Example 1. A colorant, a mother red toner, a red toner and a red developer were obtained.

Comparative Example 1 The aqueous pigment dispersion was obtained without using barium sulfate when obtaining the aqueous pigment dispersion for the blue pigment, yellow pigment and red pigment used in Examples 1, 2, and 3.
The obtained aqueous pigment dispersion was dried to obtain a powder pigment, and this was used as a colorant to obtain a color toner of each color.

Comparative Example 2 An aqueous pigment dispersion, a cyan colorant, a cyan colorant, a base cyan toner, a cyan toner and a water-based pigment dispersion were prepared in the same manner as in Example 1 except that 250 parts of crude phthalocyanine was changed to 500 parts. A cyan developer was obtained.

Example 4 An aqueous pigment dispersion and yellow coloring were carried out in the same manner as in Example 1 except that 250 parts of a yellow pigment (benzidine yellow: azo type, manufactured by Toyo Ink) was used in place of the crude copper phthalocyanine of Example 1. , A base yellow toner, a yellow toner and a yellow developer.

Example 5 Red pigment (Chromophthal Red A-2B manufactured by CIBA: diaminodianthranil type)
240 parts, 1600 parts of sodium chloride and 200 parts of diethylene glycol were charged into a 1 gallon stainless steel kneader and kneaded for 3 hours. The mixture was put into 2.5 liters of warm water together with 250 parts of the colloidal silica used in Example 1, and heated to about 80 ° C. and stirred. After about 1 hour to form a slurry, filtration and water washing were repeated 5 times to remove the sodium chloride and the solvent, and in the same manner as in Example 1, an aqueous pigment dispersion having a solid content of 50%, a red colorant, a mother red toner, A red toner and a red developer were obtained.

Example 6 An aqueous pigment was prepared in the same manner as in Example 1 except that 200 parts of a blue pigment (Lionogen Blue 6505 manufactured by Toyo Ink) was used instead of the crude copper phthalocyanine of Example 1. Dispersion, cyan colorant,
A cyan colorant, a mother cyan toner, a cyan toner and a cyan developer were obtained.

Example 7 An aqueous dispersion (treated pigment dispersion) was prepared in the same manner as in Example 1 except that the crude copper phthalocyanine used in Example 1 was replaced with 250 parts of a red pigment (PARIOTOR Red L3670, manufactured by CIBA: perylene). ) Got. Thereafter, an aqueous pigment dispersion, a red colorant, a mother red toner, a red toner and a red developer were obtained in the same manner as in Example 1.

[Evaluation] (Transparency) Using a digital color copying machine, the developer of each color obtained in each Example and each Comparative Example was used, and the amount of each color toner deposited on the OHP sheet was 0.8 mg / cm. Fixing was performed so as to be ^2, and the transparency was evaluated. Table 1 shows the results. <Visual Transparency Standard> 透明: Good transparency ：: Almost transparent, but poor in sharpness and dull. X: Transparency is remarkably inferior.

(Clarity) By a digital color copying machine,
Using the developers of each color obtained in each of the examples and comparative examples, the clarity after 10,000 copies of white standard plain paper was evaluated. Table 1 shows the results. <Criterion for visual clarity> ：: The color development is good in both the dark and light portions. Δ: The dark portion is vivid but the light portion is insufficiently colored and slightly unclear. X: The dark and light portions are poorly colored and unclear.

(Fog) As in the case of the sharpness described above, the difference between the reflection density of the non-image area after copying 10,000 sheets on white standard plain paper and the reflection density of the standard plain paper was determined, and the fog situation was evaluated. Table 1 shows the results. <Fog evaluation criteria> Photobolt 577 (Photobolt) was used for measurement. ：: good fog value less than 1.0 △: practical level fog value 1.0 or more and less than 1.5 ×: impossible fog value 1.5 or more

[0046]

[Table 1]

[0047]

According to the present invention, since the organic pigment in the color toner is more finely dispersed by using barium sulfate at the time of salt milling, clearness can be obtained without impairing the optical transparency on the OHP sheet. Thus, a color toner for developing an electrostatic charge image which gives an image free from fogging and having good properties can be obtained.

Claims (9)

[Claims] A colorant (A) containing 1 to 150 parts by weight of fine barium sulfate (a2) and a binder resin (B) based on 100 parts by weight of fine organic pigment (a1). Color toner for developing electrostatic images. 2. The color toner for developing electrostatic images according to claim 1, wherein the colorant (A) is contained in an amount of 0.1 to 15% by weight. 3. The particulate organic pigment (a1) having a particle size of 0.
Fine particle barium sulfate (a2)
The color toner for developing an electrostatic image according to claim 1, wherein the particle size of the toner is 0.001 to 0.1 μm. 4. The finely divided organic pigment (a1) is at least one selected from the group consisting of quinacridone-based, phthalocyanine-based, azo-based, isoindolinone-based, dianthraquinonyl red-based, sulene-based and perylene-based pigments. The color toner for developing an electrostatic image according to any one of claims 1 to 3, wherein: 5. Fine particles obtained by mechanically mixing an organic pigment, a water-soluble inorganic salt, barium sulfate and a water-soluble solvent, followed by washing with water to remove the water-soluble inorganic salt and the water-soluble solvent. Organic pigment (a1) and fine barium sulfate (a
2. A method for producing a color toner for electrostatic image development, comprising melting and kneading a colorant (A) containing (2) and a binder resin (B). 6. A mixture of a finely divided organic pigment (a1), a finely divided barium sulfate (a2), and water obtained by removing a water-soluble inorganic salt and a water-soluble solvent, together with a resin for dispersion, using mechanical shearing force. Colorant obtained by kneading and removing water (A2)
6. The method for producing a color toner for electrostatic image development according to claim 5, wherein the resin and the binder resin (B) are melt-kneaded. 7. The fine particle organic pigment (a1) having a particle diameter of 0.
Fine particle barium sulfate (a2)
7. The method for producing a color toner for developing an electrostatic image according to claim 5, wherein the particle diameter of the toner is 0.001 to 0.1 [mu] m. 8. The process for producing a color toner for developing an electrostatic image according to claim 5, wherein the weight ratio of the water-soluble inorganic salt to the water-soluble solvent is 2 to 20 times. . 9. The particulate organic pigment (a1) is at least one selected from the group consisting of quinacridone-based, phthalocyanine-based, azo-based, isoindolinone-based, dianthraquinonyl red-based, sulene-based, and perylene-based pigments. The method for producing a color toner for developing an electrostatic image according to any one of claims 5 to 8, wherein: