JP2000035696A - Yellow toner for developing electrostatic charge image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain yellow toner for developing an electrostatic charge image hardly fading, excellent in color reproducibility and having a slight change in the quantity of electrostatic charge with respect to an environmental change by incorporating a specified compd. SOLUTION: The yellow toner contains a colorant and a bonding resin as principal components and a compd. of the formula having >=20 m2/g, preferably 30-60 m2/g, further preferably 35-55 m2/g specific surface area by the nitrogen adsorption method is contained as the colorant. The colorant is obtd. by reducing the particle diameter of an org. pigment under control. A polyester resin is preferably used as the bonding resin because it is excellent in resistance to an environmental change and colorability. The polyester resin consists preferably of an alkylene oxide additive of bisphenol A and a dicarboxylic acid. It is obtd., e.g. by bringing polybasic acids including a dicarboxylic acid and a polyol as essential components into ester condensation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a yellow toner for developing an electrostatic image for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like.

[0002]

2. Description of the Related Art In an electrophotographic method, an electrostatic latent image is generally formed by charging and exposing an electrostatic latent image carrier made of a photoconductive photoreceptor and then exposing the electrostatic latent image to a binder resin. Is developed by a toner composition containing a colorant, and the obtained toner image is transferred and fixed to a support such as transfer paper to form a visible image.

[0003] As a toner composition for obtaining such a visible image, generally, a composition in which a black colorant such as carbon black is dispersed in a binder resin is often used. In recent years, a color toner formed by dispersing cyan, magenta, and yellow colorants in a binder resin has been used to obtain a multicolor image by an electrophotographic method.

In the case of such a color toner, it is also required that a color image obtained by transferring and fixing the image on an overhead projector (hereinafter, referred to as an OHP) sheet is projected on a screen by OHP transmitted light. Have been.

In general, the composition of a color toner comprises a binder resin, a main component of a colorant, and various additives. Examples of the binder resin include polystyrene, styrene- (meth) acrylate copolymer, styrene-butadiene copolymer,
Polyester, epoxy resin, coumarone indene resin and the like are generally used.

In order to obtain a multicolor image of this color, an electrostatic latent image is formed as described above using light of each color obtained by separating a document by a color separation filter, and yellow, magenta, A method has been used in which development is repeatedly performed using a color toner such as cyan, cyan, or the like, and this is transferred and fixed on paper or the like.

Conventionally, many techniques have been disclosed for such color toners. In particular, with respect to the magenta (red) color toner, JP-A-51-24234 discloses a technology relating to a magenta toner using a quinacridone pigment.
Further, JP-A-59-165069 and JP-A-62-296167 disclose technologies relating to a magenta toner using various monoazo pigments.

[0008] Benzidine yellow is used as a pigment for the yellow toner. Benzidine yellow is superior to dyes in terms of heat resistance, color material migration (bleed), and light resistance, but is inferior to lake pigments in light resistance, so light resistance of full-color copies is also yellow. However, there is a problem that the hue changes due to long-time exposure to light due to the poor characteristics. Further, this yellow toner has a drawback that it is difficult to maintain a stable charge amount under conditions such as low temperature and low humidity or high temperature and high humidity, and image characteristics are extremely unstable with respect to changes in temperature and humidity.

From the viewpoint of environmental problems, conventional benzidine yellow often has a residual carcinogenic property, dichlorobenzidine, which is a starting material thereof, in many cases. At the time of melt kneading, toner fixing conditions, or problems such as benzidine may be volatilized when it is discarded or incinerated,
The development of an alternative yellow pigment has been awaited.

Further, a transfer image obtained by repeatedly developing a magenta, cyan, and yellow color toner and transferring it to paper or the like is generally required to have an image quality close to a natural color. For that purpose, it is important that the monochromatic toners of magenta, cyan, and yellow have excellent coloring power, transparency, and good color reproducibility, and improvements therefor have been demanded.

The colorant cannot be used as a toner with a dull color. For use as a toner, a material having a clear and clear color tone is important. For this reason, the colorant has been required to have clear color and transparency.

The monoazo yellow pigments disclosed in JP-A-2-210364 and the like do not volatilize dichlorobenzidine as described above and are often excellent in light resistance and heat resistance.
At present, a colorant suitable for a full-color toner has not been obtained because of strong hiding power and lack of transparency.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems in the prior art. That is, the problem to be solved by the present invention is to provide a yellow toner which has little fading as a yellow toner, has excellent color reproducibility, and has a small charge amount variation with respect to environmental changes from low temperature and low humidity to high temperature and high humidity. is there. Also, in so-called multi-color superimposition printing, which provides good and stable transfer image quality and uses together toners of cyan, magenta, and yellow color pigments, a full-color image that is very close to a natural color and has excellent transparency. And to provide a yellow toner. Another object is to provide a toner using a yellow pigment instead of benzidine yellow due to environmental problems.

[0014]

Means for Solving the Problems The present inventors have conducted various studies to solve the above problems, and as a result, completed the present invention.

That is, the present invention relates to a toner for developing an electrostatic charge image containing a colorant and a binder resin as main components, wherein the colorant has a specific surface area of 20 m ² / g or more as measured by a nitrogen adsorption method. A yellow toner for developing an electrostatic image, characterized by containing a compound represented by the formula:

Chemical formula 1

[0017]

Embedded image

Next, the present invention will be described in detail. The present invention
It is characterized by using a specific yellow pigment. The yellow pigment is a compound represented by the above formula 1, ie, [CIPigme
nt Yellow 97]. [CIPigment Yellow 97] itself is a known pigment. The conventionally known pigment has a specific surface area of 10 to 15 m ² and has opaque properties, and thus has been mainly used for coating applications. The present inventors have proposed a compound represented by the above Chemical Formula 1, ie, [CIPigment Yello
It has been found that the effect of the present invention can be obtained by setting w 97] to a specific surface area of 20 m ² or more, and the present invention has been achieved.

The yellow toner for developing an electrostatic image of the present invention contains, as a colorant, a compound represented by the formula 1 having a specific surface area of 20 m ² or more by a nitrogen adsorption method (hereinafter, referred to as the present colorant). It is good, especially, 30-60m
^It is preferable to use ² / g as a coloring agent. More preferably, it is preferable to use one having a thickness of 35 to 55 m ² / g.

The specific surface area by the nitrogen adsorption method is determined by measuring the specific surface area (m ² / g) by charging an appropriate amount of a sample into a cell and degassing using a Micromeritics Flowsorb 2300 model manufactured by Shimadzu Corporation. This degassing is
It can be performed at 100 ° C. for 10 to 20 minutes.

In the present invention, in order to obtain the present colorant, a conventionally known control technique for reducing the particle size of an organic pigment is suitably used. Specifically, it can be achieved by adjusting the reaction conditions of the coupling reaction during the synthesis of the pigment, or by setting the post-treatment conditions such as the heating conditions and the pH after the coupling reaction so that the pigment particle diameter becomes small. .

Here, the present colorant may or may not have the surface treatment agent adsorbed / precipitated on the surface of the colorant. Since the dispersion is good, the transparency of the color is increased and the color becomes clear, and when used as a toner, it can be a colorant having an excellent color tone.

As the method of rosin-treating the present coloring agent, any known and commonly used processing method can be adopted. For example, after dissolving rosin in a solvent, dispersing the coloring agent therein, and adsorbing rosin to the coloring agent, A method in which a colorant and a rosin liquid are filtered and the colorant is dried, or JP-A-7-188575,
There is a method in which rosin is adsorbed or precipitated on the surface of the colorant.

The rosin used at this time may be any of common rosins known and used.
There are rosins mainly containing abietic acid and dextropimaric acid, for example, natural rosins such as wood rosin and gum rosin. In addition, these are polymerized, hydrogenated, oxidized modified rosin, or
Rosin alkyd adducts, rosin alkylene oxide adducts, rosin derivatives such as rosin-modified phenols and the like can be mentioned.

In carrying out the rosin treatment, the rosin adsorbed on the coloring agent is 0.1 mass per 100 mass of the coloring agent.
To 10% by mass. Although the action of rosin itself is not well understood, the rosin-treated colorant has a clear color. Further, the dispersibility with the resin is improved, and there is an effect as a dispersant. Moreover, even a small amount has the effect. However, if the amount of the rosin is too large, the binding property with the binder resin may be weakened, and the chargeability of the finally obtained toner may be uneven.

The present coloring agent may be used by mixing with other pigments or dyes as long as the technical effects of the present invention are not impaired.

Although the binder resin is not limited, there are some resins used in the present invention that significantly improve the effects of the present invention, and these resins may be used selectively.

Next, the binder resin will be described. As the binder resin generally used, any known and commonly used resin can be used. For example, polystyrene, styrene- (meth) acrylate copolymer, styrene-butadiene copolymer, polyester resin, epoxy resin, butyral resin, xylene resin, coumarone indene resin and the like can be mentioned. The binder resin may be used alone or in combination of two or more.

As the binder resin that can be used in the present invention, a polyester resin is preferable because it is excellent in environmental change and coloring power. Among them, a linear polyester resin obtained by reacting a bisphenol A alkylene oxide adduct with a dicarboxylic acid, a dicarboxylic anhydride or a lower alkyl dicarboxylic acid as essential components, as described later, is preferable.

The polyester resin is obtained, for example, by subjecting a polybasic acid containing a dicarboxylic acid and a polyhydric alcohol to ester condensation with essential components. Of course, instead of the polybasic acid, a transesterified reaction using an ester-forming derivative may be used. Ester-forming derivatives are polybasic acid anhydrides or polybasic acid lower alkyl esters.

The specific method for obtaining the polyester resin is not particularly limited, and can be easily synthesized by known condensation polymerization in a solution. For example, a diol component as a polyhydric alcohol and a polybasic It can be obtained by using a dicarboxylic acid component as an acid and, if necessary, using a trivalent or higher carboxylic acid.

The diol component for obtaining the polyester resin includes, for example, ethylene glycol, propylene glycol, butanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, hexanediol, neopentyl glycol, cyclohexanedimethanol, hydrogenated bisphenol A, An alkylene oxide adduct of bisphenol A, for example, a propylene oxide adduct of bisphenol A, an ethylene oxide adduct of bisphenol A, and the like can be given.

Examples of the dicarboxylic acid component include maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, phthalic anhydride, terephthalic acid, isophthalic acid, orthophthalic acid, hexahydrophthalic anhydride, and tetrahydrophthalic anhydride. , Cyclohexanedicarboxylic acid,
Examples include methylcyclohexanedicarboxylic acid, succinic acid, malonic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, mesaconic acid, metaconic acid, and glutaconic acid. Of course, these ester-forming derivatives are
Anhydrides and lower alkyl esters can also be used.

Examples of the trivalent or higher carboxylic acid component include trimellitic acid, toluene carboxylic acid, cyclohexanetricarboxylic acid, naphthalenetricarboxylic acid, and the like.
Examples thereof include tricarboxylic acids such as butanetricarboxylic acid and the like, tetra (methylenecarboxyl) methane, and tetracarboxylic acid of pyromellitic acid. Of course, anhydrides and lower alkyl esters which are these ester-forming derivatives can also be used.

Polyester resins using a polybasic acid, an ester-forming derivative of a polybasic acid, and / or a polyhydric alcohol having an aromatic ring are preferred because of their good blocking resistance. In some cases, a polyester resin obtained by reacting a polyol with a polycarboxylic acid containing an aromatic tricarboxylic acid or a derivative thereof can also be used.

The polyester resin can be obtained by conducting a dehydration condensation reaction or a transesterification reaction using the above-mentioned raw material components in the presence of a catalyst, if necessary. The reaction temperature and reaction time at this time are not particularly limited, but are usually 150 to 300 ° C. and 2 to 24 hours.

In carrying out the above reaction, other components such as an esterification catalyst or a transesterification catalyst for promoting the reaction, such as magnesium acetate, zinc acetate, manganese acetate, lead acetate, antimony trioxide, germanium oxide, zinc oxide, Stannous oxide, dibutyltin oxide, dibutyltin dilaurate, and the like can be used as appropriate.

As the polyester resin, a powder toner for developing an electrostatic charge image may have an appropriate glass transition point and melt viscosity characteristics. For example, it was measured with a flow tester CFT-500C manufactured by Shimadzu Corporation. Viscosity 1 × 10 ⁵
Those having a poise temperature of 90 ° C. or more are preferable because of good fixing performance, and among them, those having a viscosity of 1 × 10 ⁵ poise at a temperature of 90 to 170 ° C. are preferable.

The acid value (AV) of the polyester resin is preferably 15 mgKOH / g or less from the viewpoint of improving the moisture resistance of the toner. The weight average molecular weight (Mw) of the polyester resin is preferably about 5,000 to 1,000,000. Number average molecular weight of polyester resin (M
n) is preferably about 3000 to 20,000.

On the other hand, the glass transition temperature (Tg) is 5
Those having a Tg of 5 ° C. or higher are preferred,
Those having a temperature of 5 ° C. or higher are particularly preferred.

As the coloring agent, a pigment satisfying the above properties may be used as it is, but a master batch obtained by taking out approximately the same mass of the pigment or a water-containing paste of the pigment and the binder resin and kneading them in advance is used. By doing so, the saturation can be further increased.

The charge control of the toner may be performed by the binder resin or the present coloring agent itself, but if necessary, a charge control agent which does not cause a problem in color reproduction may be used together. As the charge control agent, known and commonly used ones, for example, Bontron E
-84, Bontron E-89, Bontron P-51, Copy Charge NX, Copy Charge NEG, LR-14
7 (manufactured by Orient Chemical Industries, etc.). Among them, a charge controlling agent comprising a compound containing a boron atom,
For example, LR-147 (Nihon Carlit) is preferable because it has excellent charge control characteristics, is transparent, and has excellent color reproducibility of a yellow image.

Further, in the heat roll fixing application, various waxes are used as necessary as an auxiliary agent for enhancing the releasing effect in order to prevent the toner from adhering to the heat roll (trouble due to offset). Natural waxes such as ester waxes, polyolefin-based waxes such as high-pressure polyethylene and polypropylene, silicone-based waxes, and fluorine-based waxes can be used. A mixture of these can also be used.

Suitable waxes include, for example, Viscol 660P, Viscol 550P, Viscol 33
0P, TP-32 (manufactured by Sanyo Chemical Industries, Ltd.), Mitsui High Wax NP505, P200, P300, P
400 (manufactured by Mitsui Petrochemical Industries, Ltd.). Mn <
Those having a low number average molecular weight of 10,000 or less are preferred.

The toner of the present invention can be obtained by any known and commonly used production method. For example, it can be produced by melt-kneading a binder resin and a colorant at a temperature not lower than the melting point (softening temperature) of the binder resin, and then pulverizing and classifying. Of course, it may be manufactured by other methods such as a polymerization method or a microencapsulation method.

Specifically, for example, the binder resin and the coloring agent are mixed as essential components by a kneading means such as a two-roll, three-roll, pressure kneader or a twin-screw extruder. At this time, the colorant may be uniformly dispersed in the binder resin, and the conditions for the melt-kneading are not particularly limited. Usually, the kneading temperature is 80 to 180 ° C.

Further, the above-mentioned master batch formulation, that is, a step of preliminarily dispersing the present colorant with a part of the binder resin and further diluting the binder with the binder resin is included. The method for producing a yellow toner for developing an electrostatic image, characterized by the following, can also be adopted.

Then, the kneaded material is cooled, finely pulverized by a pulverizer such as a jet mill, and classified by an air classifier or the like. The toner particles preferably have an average particle diameter of 5 to 15 μm.

The toner powder of the present invention can be used as it is as a powder toner for developing an electrostatic image.
For example, by externally adding silica, powder fluidity and the like can be further improved, and practical characteristics can be improved.

Examples of the silica used in the present invention include those having hydrophobicity among silicon dioxides, for example, those obtained by subjecting silicon dioxide to a surface treatment with various polyorganosiloxanes, silane coupling agents, or the like. . For example, there are products marketed under the following trade names.

AEROSIL R972, R974, R
202, R805, R812, RX200, RY20
0, R809, RX50 [Nippon Aerosil Co., Ltd.] WORKER HDK H2000, H2050EP
[Wacker Chemicals East Asia Co., Ltd.] Nipsil SS-10, SS-15, SS-20,
SS-50, SS-60, SS-100, SS-50
B, SS-50F, SS-10F, SS-40, SS-
70, SS-72F, [Nippon Silica Industry Co., Ltd.]

As silica, there are silica having a relatively large average particle diameter and silica having a relatively small average particle diameter, and these may be used alone or in combination. The external addition amount of silica is preferably 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the toner particles. If the external addition amount of silica is too large, the photosensitive drum may be damaged,
It is not preferable because environmental characteristics of the toner may be deteriorated.

As a method of externally adding the silica to the toner particles, for example, a so-called surface modifier such as a Henschel mixer, which is a usual powder mixer, or a hybridizer, can be used. Incidentally, this external addition may be such that silica adheres to the surface of the toner particles,
Part of the silica may be embedded in the toner particles.

The toner of the present invention can be used in combination with a carrier.
It can also be used as a component type developer. In this case,
Usually, the toner 2 of the present invention 2 per 100 parts by mass of the carrier
A developer is prepared by mixing 10 parts by mass and used.

As the carrier used here, any known and commonly used carriers can be used. For example, ferrite, magnetite and the like can be mentioned. In addition, any of resin-coated carriers obtained by coating these with an acrylic resin, a silicon resin, a fluorine resin, or the like can be used.

The toner of the present invention can also be used as a non-magnetic one-component developer. For example, the toner is passed between the developing sleeve and the toner layer thickness regulating member pressed against it, frictionally charges the toner, and forms a thin layer of toner on the sleeve, thereby forming a thin layer of toner on the surface of the photoconductor. It can be used in a developing device based on a non-magnetic one-component developing method for developing an electrostatic latent image in a contact or non-contact state. Generally, as a material of the sleeve, silicone rubber, urethane rubber, aluminum, SUS, or the like is used.
Silicone rubber, urethane rubber and the like are used.

[0057]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention includes the following embodiments.

1. A toner for developing an electrostatic image mainly containing a colorant and a binder resin, characterized in that it contains, as a colorant, a compound represented by a chemical formula 1 having a specific surface area of 20 m ² / g or more by a nitrogen adsorption method. Yellow toner for developing electrostatic images.

[0059]

Embedded image

2. 2. The electrostatic image developing yellow toner according to the above item 1, wherein the binder is a polyester resin in the toner for developing an electrostatic image mainly containing a colorant and a binder resin.

3. 2. The yellow toner for electrostatic charge development according to the above 1, wherein the binder resin is a linear polyester resin obtained by reacting a bisphenol A alkylene oxide adduct with a dicarboxylic acid, a dicarboxylic anhydride or a lower alkyl dicarboxylic acid as essential components. .

4. 2. The yellow toner for electrostatic charge development according to the above 1, further comprising a charge control agent comprising a compound containing a boron atom.

The preferred electrostatic image developing toner of the present invention is as follows. First, as the coloring agent, the present coloring agent is kneaded in advance with a part of the binder resin and used as a master batch. As the binder resin, a bisphenol A alkylene oxide adduct and a dicarboxylic acid, a dicarboxylic anhydride or a dicarboxylic acid lower alkyl ester were reacted as essential components. AV was 15 mgKOH / g or less.
The temperature at which Tg is 55 ° C. or higher and the viscosity is 1 × 10 ⁵ poise is 9
At 5 to 165C, a linear polyester resin is preferred.

The above colorant, binder resin, charge control agent and wax are melt-kneaded so as to have the following mass ratio. The kneaded product is cooled, pulverized by a pulverizer, and further classified by a classifier to obtain toner particles.

The present colorant 1 to 10 parts Binder resin 90 to 100 parts Charge control agent 0.1 to 4 parts Wax 0.5 to 5 parts

Further, with respect to the toner particles having an average particle diameter of 5 to 15 μm, a small amount of silica is adhered or embedded in the surface of the toner particles using a powder mixer or a surface modifier.

[0067]

EXAMPLES The present invention will be described more specifically below with reference to examples and comparative examples. The present invention is not limited to the following examples unless it exceeds the gist. Hereinafter, “parts” and “%” in Examples and Comparative Examples represent “parts by mass” and “% by mass”, respectively.

(Resin Synthesis Example) Resin A Polyoxyethylene- (2,0) -2,2-bis (4-hydroxyphenyl) propane 4.8 mol Isophthalic acid 2.5 mol Terephthalic acid 2.5 mol All A flask was charged with 0.07% by weight of dibutyltin oxide based on the weight of the raw materials, and reacted at 220 ° C. to obtain a polyester resin A (weight average molecular weight of 11,00%).
0; number average molecular weight 4100). AV is 10, Tg
Is 62 ° C. and the temperature at which the viscosity becomes 1 × 10 ⁵ poise is 105 ° C.
Met.

Example 1 The same mass of the polyester resin A and the present coloring agent having a specific surface area of 40 m ^{2 as determined} by the nitrogen adsorption method were taken out and kneaded using two rolls to prepare a pigment master A. The following toner composition (1) containing the pigment master A was melt-kneaded by a pressure kneader, pulverized by a jet mill, and obtained by a pneumatic classifier to obtain a toner base having an average particle diameter of about 8 μm.

(Toner composition 1) Polyester resin A 93% by mass Pigment master (A) 6% by mass Charge control agent LR-147 (Nippon Carlit) 1% by mass

(Adjustment of Developer) A developer (1) was prepared by frictionally mixing 5% by mass of the toner (1) and 95% by mass of a carrier “Ferrite Carrier 150” manufactured by Powdertech.

(Measurement of Charge Amount) The developer (1) prepared by using the toner (1) was subjected to high temperature and high humidity [HH] (40 ° C., 90%
RH), room temperature and normal humidity [NN] (20 ° C., 50% RH), and low temperature and low humidity [LL] (10 ° C., 20% RH) for 1 hour. It was measured.
In addition, as the environmental difference, the charge amount fluctuation width (H
H: NN: LL: difference between the maximum value and the minimum value of the charge amount under each environmental condition) was calculated and evaluated. The results are shown in Table 1.

(Evaluation of tinting strength) The developer (1) prepared using the toner (1) was placed in a commercially available copier of a two-component developing system to obtain a yellow image. For this image, the image density of the image portion was measured with a Macbeth densitometer. Table 1 shows the results.

(Evaluation of Fading) The developer (1) prepared using the toner (1) was placed in a commercially available copying machine (same as above) to obtain a yellow image. This image was exposed for 100 hours using an accelerated light resistance tester (SUN TEST CPS, manufactured by Heraeus), and the density of the printed matter after exposure was measured with a Macbeth densitometer.
The residual rate was determined by the following equation. The results are shown in Table 1. Residual rate (%) = (density after exposure / density before exposure) × 100

(Example 2) Epoxy resin B (trade name: Epicron 405, manufactured by Dainippon Ink and Chemicals, Inc.)
The present colorant having a specific surface area of 40 m ² by a nitrogen adsorption method was taken out at a ratio of the mass of the resin to the colorant 1 and kneaded using two rolls to prepare a pigment master (B). The following toner composition (2) containing the pigment master was melt-kneaded by a pressure kneader, pulverized by a jet mill, and classified by an airflow classifier to obtain a toner base having an average particle diameter of about 8 μm.

Toner composition (2) Epoxy resin B 93% Pigment master (B) 6% Charge control agent LR-147 (Nippon Carlit) 1%

(Adjustment of developer) 5% of this toner (2) and a carrier “Ferrite carrier F-
The developer 2 was prepared by friction mixing of 150% and 95%.

Thereafter, in the same manner as in Example 1, the amount of charge, the amount of coloring and the light fastness were measured. Table 1 shows the results.

Each toner prepared by adding 1 part by weight of Aerosil R972 (hydrophobic silica) to 100 parts by weight of each toner of Examples 1 and 2 was prepared and evaluated in the same manner. And the fluidity of the toner was superior to that of Comparative Example 2.

(Comparative Example 1) Instead of the present coloring agent having a specific surface area of 40 m ² by the nitrogen adsorption method, a disazo yellow pigment “Symu, manufactured by Dainippon Ink and Chemicals, Inc.
lar Fast YELLOW 8GF (CI Pigment Yellow 17) ", except that toner 3 was obtained in the same manner as in Example 1.

(Comparative Example 2) A commercially available monoazo yellow pigment “manufactured by Arimoto Chemical Co., trade name: YELLOW 950 (CI) was used instead of the present coloring agent having a specific surface area of 40 m ² by a nitrogen adsorption method.
Pigment Yellow 97) ”(small specific surface area), except that the same amount was used.

[0082]

[Table 1]

As shown in the results in Table 1, it was found that the toners of Examples 1 and 2 had a stable charge amount under each temperature and humidity condition and an excellent residual ratio as compared with Comparative Example 1. The toner of Comparative Example 1 had a poor charge amount under HH conditions and was not practically usable. The toner of Comparative Example 2 was excellent in the stability of the charge amount, but was inferior in transparency, and was not on a practical level as a full-color toner. The polyester resin of Example 1 had clear image characteristics, and it was found that the pigment of Chemical Formula 1 had good compatibility with the polyester resin.

[0084]

According to the present invention, a compound represented by the formula (1) having a specific surface area of 20 m ² or more as measured by a nitrogen adsorption method is contained as a coloring agent, whereby the temperature is changed from low temperature and low humidity (LL) to high temperature and high humidity (HH). Little change in charge amount due to environmental changes,
Moreover, a yellow toner having excellent transparency was obtained. In addition, this coloring agent is also suitable for environmental problems, and the toner naturally clears environmental problems.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takeshi Isonaka 1-102-2 Sugaya, Ageo-shi, Saitama Otsuka No. 2 Building 207 F-term (reference) 2H005 AA01 AA06 AA21 CA08 CA21 CA25 DA02 DA04 EA10

Claims (4)

[Claims] 1. A toner for developing an electrostatic image mainly comprising a colorant and a binder resin, wherein a compound represented by the chemical formula 1 having a specific surface area of at least 20 m ² / g by a nitrogen adsorption method is used as a colorant. A yellow toner for developing an electrostatic charge image, comprising: Embedded image 2. The yellow toner for electrostatic charge development according to claim 1, wherein the binder resin is a polyester resin. 3. The binder resin according to claim 1, wherein the binder resin is a linear polyester resin obtained by reacting a bisphenol A alkylene oxide adduct with a dicarboxylic acid, dicarboxylic anhydride or dicarboxylic acid lower alkyl ester as essential components.
The yellow toner for electrostatic charge development according to the above. 4. The yellow toner for electrostatic charge development according to claim 1, further comprising a charge control agent comprising a compound containing a boron atom.