JPH09204074A - Toner for developing electrostatic charge image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain satisfactory kick-off of electrostatic charge and to reproduce a stable image over a long time even by repetitive development by using an electric charge controlling agent which is a hydrophobic body of a specified xanthene dye by a specified amt. based on the amt. of a bonding resin. SOLUTION: This toner consists of a bonding resin, a colorant and an electric charge controlling agent which is a hydrophobic body of a xanthene dye represented by formula I. The electric charge controlling agent is contained by 0.05-10 pts.wt. per 100 pts.wt. of the bonding resin. In the formula I, each of R1 , R3 and R5 -R7 is H or lower alkyl, each of R2 and R4 is lower alkyl and A is a group represented by formula II, etc. In the formula II, R8 is 8-37C alkyl. The electric charge controlling agent preferably contains an inorg. pigment such as calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, magnesium hydroxide, aluminum hydroxide, calcium silicate or aluminum silicate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner containing a charge control agent useful for a toner which is a developer for electrophotography.

[0002]

2. Description of the Related Art In electrophotography, an electrostatic latent image is formed on a photoconductor layer composed of a photoconductive material and the like, developed with a powder developer, visualized, and fixed with heat or a solvent. The method of doing is general. The photoconductor layer can be positively or negatively charged so that exposure under the original results in a positive or negative electrostatic latent image. Therefore, when a negative electrostatic latent image is developed with a positively charged developing powder, a positive-positive image corresponding to the original is produced.

As such an electrophotographic developer, a mixture of fine particle powder called a toner, which is composed of a binder resin and a colorant, and fine iron powder or ferrite powder called a carrier, is used.

In the powder toner, a binder resin which is an essential component is heated and melted, carbon as a coloring agent and a charge control agent are added thereto, dispersed by kneading, cooled, and then mechanically pulverized. Generally, the method of classification and then obtaining is common.

The toner develops the latent image on the photosensitive member by a mechanism that causes electrification by friction with a carrier (two-component developer) and friction with a sleeve (one-component developer). Since the toner is consumed by the development, it is always replenished, but the replenished toner does not have an electric charge, so the toner is raised to a predetermined charge amount by stirring in the developing unit and friction on the sleeve. The charge amount of toner is often set to about 10 to 30 μC / g.

Controlling the chargeability of toner is the most important matter for toner. The charging characteristics of the toner are governed by the binder resin, which is the main component thereof, but normally, the desired triboelectric charging characteristics are obtained by adding a charge control agent. Due to the recent demand for higher image quality, higher reliability, higher speed, etc., more precise charge control than in the past has become necessary. In particular, a charge control agent that has a faster charge rise and is stable against environmental changes and aging There is a strong demand.

In order to perform good development, a predetermined charge amount
How quickly the replenishment toner is started up is one of the characteristics required of the toner. If the toner has a poor start-up, low-charged toner is generated, it does not migrate to the photoconductor sufficiently, which causes a decrease in density. In addition, toner scattering occurs, background stains on the copy, copy Contamination inside the machine may occur or the developer may deteriorate faster.

In the case of a low speed copying machine, it can be covered to some extent by agitation in the developing section, but as the speed of the developing machine increases, the replenished toner is transferred from the developing section to the photoconductor more quickly, so that quick charging is performed. Is required to rise. Further, in the case of the one-component toner, the charging property must be generated only by the friction with the sleeve, not the friction with the carrier. Therefore, the rising property is more important than the two-component toner.

As a conventional charge control agent, oil black,
Nigrosine [Japanese Patent Publication No. 48-25669] aniline black, crystal violet and the like have been proposed. However, the proposed charge control agent has a compatibility relationship with the binder resin, so that it is difficult to uniformly mix with the binder resin during the production of the toner, leaving various problems in various properties of the toner. . In addition, rhodamine dye and phosphorus,
As a charge control agent composed of tungsten and molybdic acid, JP-A-6-214428, rhodamine dye and P
JP-A-62-278571 discloses a charge control agent comprising -toluenesulfonic acid, but it still has the same problem.

In the case of a toner, it is very important to uniformly disperse the charge control agent in the binder resin. If the dispersibility is poor, the charge control agent is not uniformly mixed in the toner particles, and the toner is The non-uniformity of the quality occurs, the rise of the charging is lowered, and the change over time easily occurs. The toner using the above charge control agent is still unsatisfactory as a charge control agent for toner, because it has a problem that the charge is not stable at high temperature and high humidity.

[0011]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, has a good rise in charging, is not affected by changes in temperature and humidity even when repeated development is carried out by continuous use, and can be used for a long time. It is an object of the present invention to provide a toner containing a charge control agent or a charge control agent composition having good performance capable of reproducing a stable image internally.

[0012]

As a result of various studies to solve these problems, the present inventors have identified a specific xanthene dye hydrophobized compound or a xanthene dye hydrophobized compound which is a charge control agent. It was found that the charge control agent composition modified and prepared with the inorganic pigment of 1 has a characteristic that the dispersibility in a resin is extremely good,
Toners using these are found to solve the above-mentioned problems, that is, the problems of accelerating the rise of charging, improving the stability of charging performance, and preventing the scattering of toner and the occurrence of image defects. The present invention has been completed.

That is, in the present invention, in a toner comprising at least a binder resin, a colorant and a charge control agent, the charge control agent is a hydrophobic substance of a xanthene dye represented by the following general formula (1). Further, the present invention relates to a toner for developing an electrostatic charge image, wherein the charge control agent is contained in an amount of 0.05 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

[0014]

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[In the formula, R ₁ , R ₃ , R ₅ , R ₆ and R ₇ each independently represent a hydrogen atom or a lower alkyl group, and R ₂ , R _{4 and}
Each independently represents a lower alkyl group, and A is the following general formula (2)

[0016]

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(Wherein R ₈ represents a C ₈ -C ₃₇ alkyl group), or the following general formula (3)

[0018]

[Chemical 6]

(Wherein R ₉ represents a C ₁ -C ₃₇ alkyl group, and X represents O, S, NH or CH ₂ ). Similarly, in the present invention, in a toner comprising at least a binder resin, a colorant and a charge control agent, the charge control agent is prepared from a hydrophobized xanthene dye represented by the general formula (1) and an inorganic pigment. The charge control agent composition is 0.0% with respect to 100 parts by weight of the binder resin.
The present invention relates to an electrostatic charge image developing toner characterized by being 5 to 10 parts by weight. Similarly, in the present invention, the inorganic pigment is selected from the group consisting of calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, magnesium hydroxide, aluminum hydroxide, calcium silicate, aluminum silicate, zinc silicate and magnesium silicate. The present invention relates to a toner for developing an electrostatic charge image, characterized in that it is one kind or a plurality of kinds.

As the above-mentioned inorganic pigment, either synthetic products or natural products can be used. Further, an inorganic pigment coated with an organic compound, an organic polymer, a hydrophobizing agent, a titanate coupling agent or the like can also be used. Further, it is also possible to use an inorganic pigment coated with an organic compound, an organic polymer, a hydrophobizing agent, a titanate coupling agent or the like.

The hydrophobized xanthene dye according to the present invention can be used alone as a charge control agent, or as a charge control agent composition produced by mixing with an inorganic pigment. Moreover,
It can be used in combination with existing charge control agents.

The hydrophobized xanthene dye can be obtained by dissolving the xanthene dye in warm water or an appropriate solvent and adding a hydrophobizing agent, for example, an aqueous solution of sodium dodecylbenzene sulfonate, to the reaction. .

The charge control agent composition of the present invention is prepared from a hydrophobized xanthene dye and the above-mentioned inorganic pigment. As a method for preparing the charge control agent composition from the inorganic pigment, any method can be employed as long as a homogeneous composition of both can be obtained. When producing a hydrophobized xanthene-based dye, an inorganic pigment is added at any stage of the production process, and as a final product, a homogeneous composition of the hydrophobized xanthene-based dye and the inorganic pigment as a reaction product. Is preferably obtained.

The inorganic pigment is particularly preferably added by being present together with the reaction raw material compound in the reaction system for producing the hydrophobized product of the xanthene dye. Further, the hydrophobized product may be added to the reaction mixture transferred from the production reaction step to the purification step, or may be added by mixing with the wet cake filtration product obtained from the purification step. A method may be used in which the hydrophobized product produced by the reaction is filtered out in the purification step, dried, and then immediately added with an inorganic pigment, pulverized and mixed to prepare a homogeneous composition.

By mixing the dried hydrophobized product and the inorganic pigment in a suitable solvent such as water, a mixture of water and an organic solvent, or an organic solvent alone by wet homogenization, a charge control agent composition having similar properties can be obtained. It is also possible to obtain.

The charge control agent composition comprising the xanthene dye hydrophobized product and the inorganic pigment obtained by the above method can be used as it is for the production of toner after drying, and if necessary, further pulverized, You may use it after classifying. The content of the inorganic pigment in the charge control agent composition obtained in the present invention is preferably such that the charge control agent composition does not deteriorate the characteristics as a charge control agent.

The charge control agent and the charge control agent composition of the present invention described above have good dispersibility in the binder resin, and the charge control agent and the toner using the charge control agent composition are not charged. In the environment of good start-up, low temperature and low humidity and high temperature and high humidity, it is possible to solve the problems of toner charge instability and toner scattering, which have been problems in the past, even when used for a long time, and as a result, a clear developed image can be obtained. it can.

In a general method for producing a powder toner, the temperature at which the resin is heated and melted is generally 150 ° C. or lower, although it depends on the kind of the resin. The charge control agent is dispersed therein by kneading. As the characteristics of the charge control agent, it is required that the melting point be higher than the kneading temperature and the solubility in the resin be extremely low. It is known that the charge control agent dispersed in the resin is dispersed in the form of small particles in individual toner particles obtained by pulverization and classification. Therefore, when manufacturing a charge control agent, it is important to design the charge control agent to maximize its characteristics.

The amount of the charge control agent which is a hydrophobized xanthene dye or the charge control agent composition which comprises the hydrophobized inorganic pigment is 0.05 per 100 parts by weight of the binder resin.
-10 parts by weight, preferably 0.2-10 parts by weight, particularly preferably 0.5-5 parts by weight are suitable.

The toner of the present invention further contains a binder resin and a colorant in addition to the charge control agent or the charge control agent composition. Examples of the binder resin that can be preferably used in the toner of the present invention include polystyrene, styrene such as polvinyltoluene, and monomers thereof, styrene-substituted styrene copolymers, styrene-acrylic acid ester-based copolymers, and styrene. -Methacrylic acid copolymer, styrene-acrylonitrile copolymer, polyvinyl chloride, polyethylene / silicone resin, polyester, polyurethane,
Examples thereof include polyamide, epoxy resin, modified rosin and phenol resin. However, other materials that have been used as the binder resin for toner so far are also applicable,
The charge control agent of the present invention provides good charging performance irrespective of special resin properties.

Examples of the colorant include C.I. I. Pigment Black-1, C.I. I. Solvent Black-3,
C. I. Solvent Black-22 and carbon black can be used. However, other materials that have been conventionally used as colorants for toner are also applicable.

In the present invention, the toner powder of the present invention is prepared by melting and blending the charge control agent or the charge control agent composition in a range of 0.05 to 10 parts by weight with respect to 100 parts of the binder resin and solidifying. Prepared by coarsely crushing with a hammer mill or other crusher, further finely crushing with a jet mill crusher, and then classifying with an airflow classifier, or adding a polymerization initiator to the monomer that is the raw material of the binder resin. It can be produced by adding the charge control agent or the charge control agent composition in an amount of 0.05 to 10 parts by weight to 100 parts by weight of the monomer, and polymerizing the mixture while suspending the mixture in water. .
At this time, other coloring agents such as dyes or carbon black may be added. The charge control agent or the charge control agent composition of the present invention provides good charging performance regardless of the particle toner having a particular particle size distribution.

The toner thus produced gives a charge amount suitable for developing an electrostatic latent image due to friction with a carrier, and is not affected by changes in temperature and humidity even when a phenomenon is repeated for a long time. , The charge amount is kept constant,
The charge distribution is also uniform and is kept constant.

As a carrier, a magnetic core of iron powder, ferrite or the like, a styrene-methylmethacrylate copolymer, a silicone resin, a mixed resin of a styrene-methylmethacrylate copolymer and a silicone resin, a fluorine-based polymer such as a tetrafluorostyrene polymer, etc. A carrier coated with a resin or the like can be used. Further, the charge control agent or the charge control agent composition according to the present invention provides excellent chargeability even when used in a so-called one-component toner containing a magnetic material. It can also be used as a capsule toner and a polymerized toner.
Further, the non-magnetic one-component toner also has excellent charging performance.

Examples of the magnetic material used as the magnetic material include fine metal powders of iron, nickel, cobalt and the like, alloys of metals such as iron, cobalt, copper, aluminum, nickel and zinc, aluminum oxide, iron oxide and oxide. Metal oxides such as titanium, iron, manganese, nickel, cobalt,
Ferrites such as zinc, vanadium nitride, nitrides such as chromium nitride, tungsten carbide, carbides such as silicon carbide and mixtures thereof can be used.
As the magnetic material, iron oxide such as magnetite, hematite, and ferrite is preferable. The charge control agents of the present invention provide good charging performance irrespective of special magnetic properties.

[0036]

EXAMPLES The present invention will be specifically described below with reference to Examples of production of the charge control agent and the composition of the charge control agent and use of the charge control agent composition as a toner. However, the present invention is not limited to these Examples. Is not limited by. The amounts and parts of each component described in the examples are parts by weight unless otherwise specified.

(Example 1) Rhodamine 6GCPN 1
8.8 parts are dissolved in 540 parts of warm water by stirring at 80 to 90 ° C. After 31.0 parts of aluminum silicate [OS-Clay Sanyo Clay Co., Ltd.] was added thereto, a solution of 14.0 parts of sodium dodecylbenzenesulfonate and 150 parts of water was added. The precipitated red solid matter was filtered off and washed thoroughly with water. After drying, 59.8 parts of a composition 1 comprising a hydrophobized rhodamine dye represented by the following formula (4) and aluminum silicate was obtained.

[0038]

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Next, 88 parts of styrene-n-butyl methacrylate copolymer resin [made by Heimer SBM-73F Sanyo Chemical Co., Ltd.], 5 parts of low molecular weight polypropylene [Viscole 55O-P made by Sanyo Chemical Co., Ltd.], carbon black [# 44 Mitsubishi Kasei Co., Ltd.] 5 parts and 2 parts of composition 1 were premixed, melt-kneaded, further pulverized and classified to obtain a toner having a particle size of 5 to 25 μm. To 3 parts of this toner, iron powder carrier [TEFV 200 /
300 parts, manufactured by Powder Tech Co., Ltd.] 97 parts were mixed to prepare a developer. After this developer was stirred, the amount of tribo charge was measured with a blow-off charge measuring device (manufactured by Toshiba Chemical). As a result, the charge amount was +20 μC / g. Also,
When this toner was put into a developing device and continuous copying was performed to perform an image test, a good image was obtained at the start, and the image quality did not change even after 50,000 sheets, and toner scattering and offset did not occur. It was Furthermore, 35 ° C, 85%
Even under the high temperature and high humidity of RH and the low temperature and low humidity environment of 10 ° C. and 30% RH, the image quality equivalent to the copying under the normal temperature and normal humidity environment was obtained. Further, neither toner scattering nor offset occurred.

Example 2 Rhodamine 6GCPN18.
8 parts are dissolved in 540 parts of warm water by stirring at 80 to 90 ° C. 31 parts of aluminum silicate [OS-Clay Sanyo Clay Co., Ltd.] was added thereto, and then dodecylbenzene-biphenyl ether-sodium disulfonate 1
A solution consisting of 0.9 parts and 150 parts of water was added. The precipitated red solid matter was filtered off and washed thoroughly with water. After drying, 60.7 parts of a composition 2 comprising a hydrophobized rhodamine dye represented by the following formula (5) and aluminum silicate was obtained.

[0041]

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Next, a toner was prepared in the same manner as in Example 1 except that the composition 1 was replaced with the composition 2, and then the tribo charge amount was measured. As a result, the charge amount is +19.2 μC /
g. Also, when this toner was put in the developing device and continuous copying was performed and an image test was conducted, at the start,
A good image was obtained, the image quality did not change even after 50,000 sheets, and neither toner scattering nor offset occurred. Furthermore, good image quality was obtained without being exposed to high temperature / high humidity and low temperature / low humidity environments.

Example 3 A toner having a particle size of 5 to 25 μm was obtained by the same treatment as in Example 1 except that the composition 1 was used and the raw materials used in the preparation of the toner were changed to the compositions shown below. Polyester resin [HP-313 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.] 88 parts Low molecular weight polypropylene [Viscor 550-P manufactured by Sanyo Kasei Co., Ltd.] 5 parts Carbon black [manufactured by ELFTEX-8 Cabot Co.] 5 parts Composition 1 2 parts To 3 parts of this toner, iron powder carrier [TEFV 20
0/300, manufactured by Powder Tech Co., Ltd.] 97 parts were mixed to prepare a developer. After stirring this developer, the amount of tribo charge was measured with a blow-off charge measuring device (manufactured by Toshiba Chemical Co.). As a result, the charge amount was +18.0 μC / g.
Further, when this toner was put in a developing device and continuous copying was performed and an image test was performed, a good image was obtained at the start, the image quality did not change even after 50,000 sheets, and toner scattering and offset did not occur. . Further, good image quality was obtained without being affected by the environment of high temperature and high humidity and low temperature and low humidity.

Example 4 A toner was prepared in the same manner as in Example 3 except that the composition 1 was replaced by the composition 2, and the triboelectric charge amount was measured. As a result, the charge amount was +18.0 μC / g. An image test was performed and good image quality was obtained.

(Example 5) Rhodamine 6GCPN 1
8.8 parts are dissolved in 540 parts of warm water by stirring at 80 to 90 ° C. After adding 28.4 parts of aluminum silicate [OS-Clay Sanyo Clay Co., Ltd.] thereto, a solution of 11.8 parts of sodium n-octylbenzenesulfonate and 150 parts of water was added. The precipitated red solid was filtered off and washed thoroughly with water. After drying, 55.9 parts of a composition 3 comprising a hydrophobized rhodamine dye represented by the following formula (b) and aluminum silicate was obtained.

[0046]

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Next, a toner was prepared in the same manner as in Example 1 except that the composition 1 was replaced with the composition 3, and then the tribo charge amount was measured. As a result, charge amount +20.0 μC / g
Met. In addition, when this toner was put into a developing device, continuous copying was performed, and an image test was performed, a good image was obtained at the start, and the image quality did not change even after 50,000 sheets, and toner scattering and offset occurred. There was no. Furthermore, good image quality was obtained without being exposed to high temperature / high humidity and low temperature / low humidity environments.

(Comparative Example 1) Rhodamine 6GCPN 1
8.8 parts are dissolved in 540 parts of warm water by stirring at 80 to 90 ° C. 24 parts of aluminum silicate [OS-Clay Sanyo Clay Co., Ltd.] was added thereto, and then a solution of 7.8 parts of sodium P-toluenesulfonate and 150 parts of water was added. The precipitated red solid matter was filtered off and washed thoroughly with water. After drying, 45.5 parts of a comparative composition 4 comprising a hydrophobized rhodamine dye represented by the following formula (7) and aluminum silicate was obtained.

[0049]

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Next, a toner was prepared in the same manner as in Example 1 except that the composition 1 was replaced with the composition 4 for comparison, and the triboelectric charge amount was measured. As a result, the charge amount is +
It was 19.2 μC / g.

(Example 6) Rhodamine 6GCPN 1
2.1 parts are dissolved in 350 parts of warm water with stirring at 80 to 90 ° C. A solution consisting of 9.0 parts of sodium dodecylbenzenesulfonate and 100 parts of water was poured therein. The precipitated red solid matter was filtered off and washed thoroughly with water. This was dried to obtain 20 parts of a hydrophobized rhodamine dye represented by the following formula (8) (compound (1)).

[0052]

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Next, 88 parts of styrene-n-butylmethacrylate copolymer resin [Haimer SBN-73F Sanyo Chemical Co., Ltd.], 5 parts of low molecular weight polypropylene [Viscor 550-P Sanyo Chemical Co., Ltd.], carbon After premixing 5 parts of black [# 44 Mitsubishi Kasei Co., Ltd.] and 2 parts of the above compound (1), melt kneading and further pulverizing,
By classification, a toner having a particle size of 5 to 25 μm was obtained. To 3 parts of this toner, iron powder carrier [TEFV 200 /
300 parts, manufactured by Powder Tech Co., Ltd.] 97 parts were mixed to prepare a developer. After this developer was stirred, the amount of tribo charge was measured with a blow-off charge measuring device (manufactured by Toshiba Chemical). As a result, the charge amount was +22 μC / g. When this toner was put in a developing device and continuously copied and an image test was performed, a good result was obtained at the start, the image quality did not change after 50,000 sheets, and neither toner scattering nor offset occurred. Further, good image quality was obtained without being affected by the environment of high temperature / high humidity and low temperature / low humidity.

(Comparative Example 2) Rhodamine 6GCPN 1
8.8 parts are dissolved in 540 parts of warm water by stirring at 80 to 90 ° C. After adding 31 parts of aluminum silicate [OS-Clay Sanyo Clay Co., Ltd.] to it, 9.6 parts of sodium tungstate, 28.1 parts of sodium molybdate, 4.4 parts of sodium phosphate and 100 parts of water are added. In addition to 28.
The raking agent prepared by adding 8 parts was added. The precipitated red lake compound was filtered off and thoroughly washed with water. After drying, 68.6 parts of a composition 5 for comparison containing a compound represented by the following formula (9) was obtained.

[0055]

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Next, a toner was prepared in the same manner as in Example 1 except that the composition 1 was replaced with the composition 5, and then the tribo charge amount was measured. The charge amount was +3.5 μC / g.

Comparative Example 3 A toner was prepared in the same manner as in Example 3 except that the composition 1 was replaced with the composition 5, and then the triboelectric charge amount was measured. As a result, the charge amount was −1.2 μC / g.

[0058]

EFFECTS OF THE INVENTION From each of the examples and comparative examples, when a hydrophobized product of the xanthene dye or a composition comprising the hydrophobized product and an inorganic pigment is used as a charge control agent, the dispersion in the binder resin becomes extremely good, It can be seen that each of the toner particles can have good charging characteristics, that is, a uniform charging level and excellent charge retention. Along with this, it becomes possible to disperse the toner particles and the carrier in a short time, the charge rises quickly, and the copy speed can be increased. At the same time, the long life of the toner and high temperature
It is less susceptible to environmental changes such as high humidity, low temperature and low humidity.

[0059]

[Table 1]

[0060]

[Table 2]

Claims (3)

[Claims] 1. A toner comprising at least a binder resin, a colorant and a charge control agent, wherein the charge control agent is a hydrophobic substance of a xanthene dye represented by the following general formula (1), and the charge control agent: Is 0.05 to 10 parts by weight with respect to 100 parts by weight of the binder resin. Embedded image [In the formula, R ₁ , R ₃ , R ₅ , R ₆ and R ₇ each independently represent hydrogen or a lower alkyl group, R ₂ and R ₄ each independently represent a lower alkyl group, and A is the following general formula: (2) [Chemical formula 2] (In the formula, R ₈ represents a C ₈ -C ₃₇ alkyl group), or the following general formula (3): (In the formula, R ₉ represents a C _{1 to} C ₃₇ alkyl group, X represents O,
Represents S, NH or CH ₂ ). ] 2. A toner comprising at least a binder resin, a colorant and a charge control agent, wherein the charge control agent is prepared from a hydrophobic substance of a xanthene dye represented by the general formula (1) and an inorganic pigment. A toner for developing an electrostatic charge image, wherein the charge control agent composition is contained in an amount of 0.05 to 10 parts by weight based on 100 parts of the binder resin. 3. In the charge control agent composition, the inorganic pigment is calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, magnesium hydroxide, aluminum hydroxide, calcium silicate, aluminum silicate, zinc silicate, silicic acid. The toner for developing an electrostatic charge image according to claim 2, wherein the toner is one or more selected from the group consisting of magnesium.