JP2001324837A - Pigment composition and toner for electrostatic charge image by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a toner for development of electrostatic charge image having excellent heat resistance in sharpness and color reproducibility. SOLUTION: The pigment composition for the toner for development of an electrostatic charge image comprises two or more kinds of monoazo pigments (X) in such a manner that at least a part of pigments (Xn+1), (Xn+2), etc., is uniformly adsorbed to the surface of primary particles of a pigment (Xn) or is included in the crystal structure of the pigment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an azo pigment composition used as a toner for developing an electrostatic image, and more particularly to an azo pigment composition used in electrophotography, electrostatic recording and electrostatic printing. The present invention relates to an electrostatic image developing toner for developing an image.

[0002]

2. Description of the Related Art Monoazo yellow pigments have long been used as colorants for printing inks, paints, plastics and the like. Further, in recent years, the use of the same as a toner for developing an electrostatic image for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing, etc.
It is disclosed in 136865. More specifically, the publication discloses, for example, C.I. I. Pigment Yellow
It is described that 65 and 74 can be used.

[0003]

However, there is no such fact that any of the commonly used monoazo yellow pigments can be diverted for electrostatic image development. As a result, the intrinsic required characteristics due to the development method and the like are imposed, so that only a very small part of the monoazo yellow pigment can be used. For example, monoazo yellow pigments, when used alone in the same application, often have insufficient heat resistance, and even when used in combination, simply mixing both does not provide sufficient heat resistance. There was a disadvantage. That is, for example, when used in a toner for electrostatic charge development that has undergone a heat setting process, it lacks sharpness and color reproducibility. The problem to be solved by the present invention is to provide, for example, a heat-resistant monoazo yellow pigment composition which can be used satisfactorily even with a toner for electrostatic charge development through a heat setting process, and a toner for electrostatic charge development using the same. Is what you do.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have conducted a reaction using a combination of a specific diazonium compound and a specific coupler to obtain two or more monoazo pigments (X), Pigments (xn + 1), (xn
+2) If at least a part of the pigment (xn) is uniformly adsorbed on the surface of the primary particles of the pigment (xn) or included in the crystal structure, each of these pigments (X) is produced separately. It has been found that a pigment composition having remarkably improved heat resistance can be obtained for a toner for developing an electrostatic charge image as compared with a case where the toner is mixed and used, and the present invention has been completed.

That is, the present invention provides the following invention. 1. And at least a part of the pigments (xn + 1), (xn + 2)...
n) A pigment composition for a toner for developing an electrostatic image, which is uniformly adsorbed on the surface of the primary particles or contained in a crystal structure.

[0006] 2. The monoazo pigment (X) is replaced by the pigment (xn)
Barrel, C.I. I. Pigment Yellow 74 and pigment (x
n + 1), (xn + 2) ... The monoazo pigment obtained by reacting a diazonium salt of an aniline compound other than the diazonium salt of 2-methoxy-4-nitroaniline with 2-methoxyacetoacetic acid arylamide. Pigment composition.

[0007] 3. 2. The pigment composition according to the above 1, wherein two or more kinds of monoazo pigments (X) are simultaneously produced.

[0008] 4. 4. A toner for electrostatic charge development, comprising the pigment composition according to 1, 2, or 3.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The pigment composition of the present invention comprises two or more monoazo pigments (X), and comprises a pigment (xn + 1),
At least a part of (xn + 2) is uniformly adsorbed on the surface of the primary particles of the pigment (xn) or is contained in the crystal structure. In the present invention, the pigment (xn) means the n-th pigment and the main pigment, and the pigment (xn + 1) refers to the (n + 1) -th pigment and the pigment (xn
+2) means the (n + 2) th pigment. n is a natural number of 10 or less, preferably a natural number of 1 to 3. When, for example, three types are used as the pigment (X) and the main pigment is the first pigment, the pigment (x1) and the other pigments can be displayed as (x2) and (x3).

As the monoazo pigment (X) that can be used in the present invention, those generally known as monoazo yellow pigments can be used. For example, C.I. I. Pigment Yellow 1, C.I. I. Pigment Yellow 3, C.I.
I. Pigment Yellow 5, C.I. I. Pigment Yellow 49, C.I. I. Pigment Yellow 65, C.I.
I. Pigment Yellow 74, C.I. I. Pigment
Yellow 97, C.I. I. Pigment Yellow 203 and the like.

The monoazo pigment (X) is composed of a diazonium salt of an aniline compound serving as a base amine and a 2-azo compound serving as a coupler.
Obtained by reaction with methoxyacetoacetic arylamide. Typically, 2-methoxyacetoacetanilide is used as the 2-methoxyacetoacetate arylamide.

C. I. Pigment Yellow 74 is obtained by reacting a diazonium salt of 2-methoxy-4-nitroaniline with 2-methoxyacetoacetanilide.

C. I. Pigment Yellow 65 is obtained by reacting 2-nitro-4-methoxyaniline diazonium salt with 2-methoxyacetoacetanilide.

C. I. Pigment Yellow 203 is obtained by reacting 2-nitro-4-methylaniline diazonium salt with 2-methoxyacetoacetanilide.

In the present invention, as a combination of two or more pigments (X), the main pigment (xn), C.I. I. Pigment Yellow 74, pigments (xn + 1), (xn + 2)
... A combination of a monoazo pigment obtained by reacting a diazonium salt of an aniline compound other than a diazonium salt of 2-methoxy-4-nitroaniline with 2-methoxyacetoacetic acid arylamide is preferred.

Pigments (xn + 1), (xn + 2) ... Barrel monoazo pigments include C.I. I. Pigment Yellow 65 or C.I. I. Pigment Yellow 203 is preferred.

In the pigment composition of the present invention, the monoazo pigment (X) is based on 100 parts by weight of one main pigment (x1), and the other pigments (x2), (x3).
To 100 parts by weight.

If two or more kinds of the monoazo pigments (X) are formed at the same time instead of separately preparing them and then mixing them, as a result, the more main pigment (xn) becomes near Other pigments (xn + 1), (xn +
2) can be arranged, and the heat resistance of the obtained pigment composition is further improved.

That is, two or more of the monoazo pigments (X) are
When they are formed simultaneously, the monoazo pigment (x
At least a part of (n + 1), (xn + 2)... is uniformly adsorbed on the primary particle surface of the monoazo pigment (xn), or is included in the crystal structure. ,
Other pigments (xn + 1), (xn + 2) near pigment (xn)
Etc. can be arranged.

As the aniline compound (I), which is a raw material of the azoline compound diazonium salt (A) that can be used in the present invention, an aniline compound used as a raw material of a material generally known as a monoazo yellow pigment can be used. it can. For example, C.I. I. Pigment Yellow 1
2-nitro-4-methylaniline which is a raw material of C.I.
I. Pigment Yellow 3 raw material, 2-nitro-
4-chloroaniline, C.I. I. Pigment Yellow 5
2-nitroaniline which is a raw material of C.I. I. Pigment Yellow 49, 2-methyl-4-chloroaniline, C.I. I. Pigment Yellow 65, 2-nitro-4-methoxyaniline, C.I. I. Pigment Yellow 74, 2-methoxy-4-nitroaniline, C.I. I. Pigment Yellow 97, 2-methoxy-4-sulfonamidophenyl-
5-methoxyaniline, C.I. I. Pigment Yellow 203, such as 2-nitro-4-methylaniline.

By using two or more aniline compound diazonium salts (A) as base amines and reacting them with 2-methoxyacetoacetic acid arylamide (B) as follows, two or more azoline compounds can be obtained. The monoazo pigment (X) can be produced at the same time.

The monoazo pigment (X) in the present invention can be synthesized by using a conventionally known synthesis method. For example, after preparing a mixed solution of two or more aniline compound diazonium salts (A) from two or more aniline compounds (I) and sodium nitrite, this diazonium salt solution is treated with 2-methoxyacetoacetic acid arylamide (B) The suspension is reacted with acetic acid at a pH of 3 to 6, at a temperature of 5 to 30 ° C. for a time of 30 to 180 minutes to synthesize two or more monoazo pigments (X) at the same time.

The reaction slurry containing two or more monoazo pigments (X) thus obtained can be used as it is,
Usually, the monoazo pigment (X) is isolated and used by filtering, washing with water, drying and pulverizing. Before and after the synthesis of the monoazo pigment (X), a conventionally known additive such as rosin and a surfactant can be added.

Of course, the aniline compounds represented by (I) can be used in combination of two or more. When used in combination of two or more, the proportion of the two aniline compounds used is 0.5 to 99.5 mol%, and the second component and the other components, when the whole is 100 mol%. The sum is 99.5 to 0.5 mol%. Preferably, the first component is 5-95 mol%, and the sum of the second component and the other components is 9%.
5 to 5 mol%.

Optimally, 70-95 mol% of 2-methoxy-4-nitroaniline, other aniline compound 30
５5 mol%. By doing so, a mixture of the monoazo pigment (X) mainly composed of the former monoazo pigment is obtained.

The pigment composition of the present invention can be used for a toner for electrostatic charge development.

The toner for electrostatic charge development according to the present invention includes a one-component magnetic toner containing a magnetic substance in the toner for electrostatic charge development (color toner for magnetic one-component development) and a non-magnetic one-component color toner containing no magnetic substance. Color toner (color toner for non-magnetic one-component development) or color toner for two-component color developer mixed with carrier (color toner for two-component development)
Can be used as

The one-component magnetic toner may be, for example, a colorant, a binder resin, a magnetic powder, other additives such as a charge control agent (CCA) or a release agent, etc. Can be configured.

The amount of the colorant used in the present invention in the electrostatic charge developing toner is not particularly limited, but is preferably used in a ratio of 0.5 to 25 parts by weight based on 100 parts by weight of the binder resin. In order to make the charging performance of the colorant itself more remarkable, 2 parts per 100 parts by weight of the binder resin is used.
More preferably, it is 15 parts by weight.

As the binder resin used in the toner for developing an electrostatic charge of the present invention, any known and commonly used binder resins can be used, but natural resins, synthetic resins, and natural rubbers exhibiting adhesiveness under application of heat or pressure. , Synthetic rubber, synthetic wax, etc. can be used.

The natural resin useful in the present invention is, for example, balsam resin, rosin, shellac, koval and the like, and these resins are one or more selected from vinyl resins, acrylic resins, alkyd resins, phenol resins and the like described later. It may be modified with the above resins.

Examples of the synthetic resin and synthetic wax used in the electrostatic charge developing toner of the present invention include polyvinyl chloride, polyacetal resin, polyamide, polycarbonate, polystyrene, polyacrylonitrile, polypropylene, polyethylene, fluorine resin, polyurethane, and the like. Epoxy resins, silicone resins, polyesters, melamine resins, urea resins, phenolic resins, methacrylic resins, acrylic resins, alkyd resins, vinyl resins or copolymers made from the monomer components of these resins, aliphatic or alicyclic hydrocarbons Resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax and the like.

Examples of natural or synthetic rubber materials include natural rubber, chlorinated rubber, cyclized rubber, polyisobutylene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, polybutadiene rubber, butyl rubber,
Styrene-butadiene rubber, acrylonitrile-butadiene rubber, chloroprene rubber, silicone rubber, fluorine rubber, chlorohydrin rubber and the like can be mentioned.

The binder resin used in the electrostatic charge developing toner of the present invention is not limited to these, and two or more kinds of binder resin components may be appropriately mixed and used.

Of these, styrene resins, polyester resins and epoxy resins can be advantageously used from the viewpoint of transparency and the hue of the toner.

The magnetic powder used in the toner for developing an electrostatic charge of the present invention is not particularly limited. However, it is preferable to use a magnetic powder which does not easily affect its reproduced color. iron oxides such as γ-iron oxide, yellow γ-iron oxide, and ferrite; metals such as iron, cobalt, and nickel; or these metals and aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony,
Alloys with metals such as beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, poly-1,4-bis (2,2,6,
6, -tetramethyl-4-oxyl-4-piperidyl-
Organic magnetic substances such as 1-oxyl) butadiene porphyrin metal complex, and mixtures thereof, and the like. Also,
Among them, yellow γ-iron oxide is particularly preferred from the aspect of hue.

The average particle diameter of these magnetic powders is 0.1 to 1
μm, from the viewpoint of charging stability and hue.
0.5 μm is preferred. The content of these in the toner is 30 to 1 with respect to 100 parts by weight of the binder resin.
It can be used in an amount of 50% by weight, and preferably 40 to 120% by weight based on 100 parts by weight of the binder resin from the viewpoint of charging stability and hue.

In addition to the above components, the toner for electrostatic charge development of the present invention may contain various plasticizers, resistance adjusters and charge control agents for the purpose of adjusting the thermal, electrical and physical properties of the toner as required. May be further added.

As the plasticizer, for example, dibutyl phthalate, dioctyl phthalate, etc., as the resistance adjuster, tin oxide, lead oxide, antimony oxide, etc., and as the charge control agent, quaternary ammonium salt, pyridinium salt, etc. Examples thereof include metal dyes.

Further, in the present invention, after the toner particles are produced, fine powders such as TiO ₂ , Al ₂ O ₃ , SiO _{2 and the} like are added to the toner particles to improve the fluidity of the toner, zinc stearate, phthalic acid and the like. May be added to prevent deterioration of the photoconductor.

The electrostatic charge developing toner of the present invention can be obtained by an extremely general manufacturing method irrespective of a specific manufacturing method. For example, the above components are mixed by kneading means such as an extruder, two rolls, three rolls, or a heating kneader, and after cooling, are stirred by a pulverizer such as a jet mill,
The toner is classified by an air classifier to obtain the toner for electrostatic charge development of the present invention. Incidentally, the particle diameter of the toner for electrostatic charge development of the present invention is preferably from 5 to 15 μm.

When the toner is used as the electrostatic charge developing toner for a two-component color developer, the same colorant, binder resin, and other additives as described above for the one-component magnetic toner can be used.

Further, as the carrier used in the toner for developing an electrostatic charge of the present invention, for example, iron powder, nickel powder,
Ferrite powder, glass beads, or styrene-acrylate copolymer, styrene-methacrylate copolymer, acrylate ester polymer, methacrylate ester polymer, silicone resin, polyamide resin Those coated with an ionomer resin, polyphenylene sulfide resin or the like or a mixture of these resins can be used, and the particle size thereof is 50 to 300.
Those having a range of μm are preferred.

The electrostatic charge developing toner for a two-component color developer is
The toner can be obtained by friction-mixing these carrier particles and the toner for electrostatic charge development of the present invention with a horizontal cylindrical or V-shaped container rotating mixer.

The mixing ratio between the carrier and the toner for electrostatic charge development is usually set to one in order to obtain an appropriate image density.
The toner can be used in the range of 2 to 10 parts by weight with respect to 00 parts by weight, but is preferably in the range of 3 to 6 parts by weight.

Next, embodiments of the present invention will be described based on preferred embodiments.

100 parts by weight of at least one binder resin selected from the group consisting of a styrene resin, a polyester resin and an epoxy resin, 2 to 15 parts by weight of the present pigment composition, and 40 to 1 per part by weight
Twenty parts by weight of a magnetic powder, a charge controlling agent, and a wax are kneaded at a temperature at which the binder resin melts, pulverized and classified to obtain a dry powder static powder for developing an electrostatic image having a volume average particle diameter of 5 to 15 microns. A charge developing toner is obtained.

To 100 parts by weight of the above, 0.3 to 5 parts by weight of hydrophobic silica having a smaller particle diameter than that described above is externally added, and the silica particles are adhered to the surface of the toner particles to form a magnetic or non-magnetic layer. It is a dry powder electrostatic charge developing toner for electrostatic charge image development for magnetic one-component development.

When the toner is used in the two-component developing method, 3 to 6 parts by weight per 100 parts by weight of the carrier is mixed with the toner to form a developer.

[0050]

The present invention will be described below in detail with reference to examples and comparative examples, but the present invention is not limited to these examples. Hereinafter, “parts” and “%” indicate “parts by weight” and “% by weight” unless otherwise specified.

Production Example 1 (Preparation of monoazo pigment composition by simultaneous production of two or more monoazo pigments) 2-Nitro-4-methylaniline
42 parts and 2-methoxy-4-nitroaniline 4.1
8.6 parts of 32% hydrochloric acid was added while stirring 9 parts of water in 100 parts of water. After stirring for 1 hour, 7.0 parts of 30% sodium nitrite was added in an ice bath to carry out a diazotization reaction. On the other hand, 5.74 parts of 2-methoxyacetoacetanilide was added to 100 parts of water, and 6.0 parts of 20% caustic soda was further added and dissolved by stirring. In this, 20% acetic acid 24.7
Was added over 1 hour at room temperature to precipitate the coupler. Further, 7.9 parts of 20% caustic soda was added thereto, and the pH was adjusted to 5.5. 5-15 ° C inside temperature with ice bath
While maintaining the temperature, the above-mentioned diazo solution was added over 2 hours to carry out a coupling reaction. 90 ° C after coupling is completed
And kept for 1 hour. Then, it was filtered and washed with water,
It was dried in a dryer at 0 ° C. The obtained solid was pulverized with a juicer mixer to obtain a monoazo pigment composition according to the present invention. The composition obtained here is C.I. I. Pigment
Yellow 74 and C.I. I. Pigment Yellow 203, mainly containing the former. I.
Pigment Yellow 74 on the primary particle surface. I. Pigment Yellow 203 was uniformly adsorbed or contained in the crystal structure.

Production Example 2 (Preparation of Monoazo Pigment Composition by Simultaneous Production of Two or More Monoazo Pigments) 2-Nitro-4-methylaniline
42 parts and 2-methoxy-4-nitroaniline 4.1
Instead of 9 parts, 2-nitro-4-methoxyaniline 0.1.
70 parts and 2-methoxy-4-nitroaniline 3.9
A monoazo pigment composition was prepared according to Production Example 1, except that 6 parts were used. The composition obtained here is C.I.
I. Pigment Yellow 74 and C.I. I. Pigment
Yellow 65, the former being mainly contained, and C.I. I. Pigment Yellow 74 on the primary particle surface. I. Pigment Yellow 65 was uniformly adsorbed or contained in the crystal structure.

Production Example 3 (Preparation of Monoazo Compound) 4.21 parts of 2-nitro-4-methylaniline was added to water 10
8.6 parts of 32% hydrochloric acid was added while stirring and dispersing to 0 parts. After stirring for 1 hour, 30% sodium nitrite 7.0 in an ice bath.
Was added to carry out a diazotization reaction. On the other hand, 5.74 parts of 2-methoxyacetoacetanilide was added to 100 parts of water, and 6.0 parts of 20% caustic soda was further added and dissolved by stirring. In this, 24.7 parts of 20% acetic acid was added at room temperature for 1 hour.
Over time, the coupler was precipitated. Further, 7.9 parts of 20% caustic soda was added thereto, and the pH was adjusted to 5.5. While maintaining the internal temperature at 5 to 15 ° C. in an ice bath, the diazo solution was added over 2 hours to carry out a coupling reaction to prepare an aqueous slurry of a monoazo compound.

Production Example 4 (Preparation of Monoazo Pigment) 4.66 parts of 2-methoxy-4-nitroaniline was added to water 1
While stirring and dispersing to 00 parts, 8.6 parts of 32% hydrochloric acid was added. After stirring for 1 hour, 30% sodium nitrite 7.0 in an ice bath.
Was added to carry out a diazotization reaction. On the other hand, 5.74 parts of 2-methoxyacetoacetanilide was added to 100 parts of water, and 6.0 parts of 20% caustic soda was further added and dissolved by stirring. In this, 24.7 parts of 20% acetic acid was added at room temperature for 1 hour.
Over time, the coupler was precipitated. Further, 7.9 parts of 20% caustic soda was added thereto, and the pH was adjusted to 5.5. While maintaining the internal temperature at 5 to 15 ° C. in an ice bath, the diazo solution was added over 2 hours to carry out a coupling reaction to prepare an aqueous slurry of a monoazo compound.

Preparation Example 5 (Preparation of Monoazo Pigment Composition by Post-Mixing of Two or More Monoazo Pigments) Aqueous slurry of monoazo compound prepared in Preparation Example 3 (10 parts as monoazo compound) and Preparation Example 4 After mixing with an aqueous slurry of a monoazo pigment (90 parts as a monoazo pigment) at room temperature, the mixture was heated to 90 ° C and held for 1 hour. Next, it was filtered, washed with water, and dried with a dryer at 90 ° C. The obtained solid was pulverized with a juicer mixer to obtain a monoazo pigment composition according to the present invention.

Production Example 6 (Preparation of Monoazo Pigment CI Pigment Yellow 74 by Conventional Method) While stirring and dispersing 4.66 parts of 2-methoxy-4-nitroaniline in 100 parts of water, 32%
8.6 parts of hydrochloric acid were added. After stirring for 1 hour, 30%
7.0 parts of sodium nitrite was added to carry out a diazotization reaction.
On the other hand, 5.74 parts of 2-methoxyacetoacetanilide was added to 100 parts of water, and further, 20% sodium hydroxide 6.0 was added.
Was added and dissolved by stirring. In this, 20% acetic acid 24.
7 parts were added over 1 hour at room temperature to precipitate the coupler. Further, 7.9 parts of 20% caustic soda was added thereto, and the pH was adjusted to 5.5. 5-15 ° C inside temperature with ice bath
While maintaining the temperature, the above-mentioned diazo liquid was added over 2 hours, and a coupling reaction was carried out to prepare an aqueous slurry of a monoazo compound. After completion of the coupling, the mixture is heated to 90 ° C.
Hold for hours. Next, it was filtered, washed with water, and dried with a dryer at 90 ° C. The obtained solid was pulverized with a juicer mixer to obtain a monoazo yellow pigment according to a conventional method.

Example 1 [Production of Toner for Electrostatic Development] Styrene-acrylic acid copolymer (Hymer SBM100, manufactured by Sanyo Chemical Industries, Ltd.) 100.0 parts Monoazo pigment composition produced in Production Example 1 5.0 Part Yellow γ-iron oxide (MAPICO Y-LOP, manufactured by Titanium Industry Co., Ltd.) 40.0 parts

After kneading the above components with an extruder, the mixture is pulverized and classified by a jet mill to obtain a toner having an average particle diameter of 10 μm. This was mixed to obtain a one-component yellow magnetic toner.

[Evaluation of toner for electrostatic charge development] A dry plain paper copying machine (Recopy FT3010, manufactured by Ricoh Co., Ltd .; same hereafter) was developed using this one-component yellow magnetic toner. A clear yellow image without background fog was obtained.

Next, C.I. I. Pigment Yellow
When development was performed in combination with a cyan developer using ow 15: 3, a clear green color was reproduced.

Further, C.I. I. Pigment Red 1
When developed in combination with a magenta developer using No. 22, a clear orange color was reproduced.

Example 2, Comparative Example 1 The monoazo pigment compositions shown in Table 1 were used in place of the monoazo pigment compositions produced in Production Example 1, respectively.
To prepare a developer.

The obtained developer was subjected to a development test in the same manner as in Example 1 using a dry plain paper copying machine (Recopy FT3010, manufactured by Ricoh Co., Ltd.). The results are shown in Table 1. As is clear from Table 1, the heat resistance of the monoazo pigment composition according to the present invention was improved, so that a clear image was obtained from the developer using the same, but the image was obtained by a conventionally known method. The resulting monoazo yellow pigment was inferior in heat resistance, so that an image obtained from a developer using the same was unclear.

A developer using the monoazo pigment composition according to the present invention, a C.I. I. Pigment Yellow
ow 15: 3 in combination with a cyan developer, C.I. I. When combined development with a magenta developer using Pigment Red 122 was performed, clear green and orange colors were reproduced, respectively.

On the other hand, a developer using a monoazo yellow pigment obtained by a conventionally known method, a C.I. I. P
C.I. Yellow 15: 3 in combination with a cyan developer, C.I. I. Pigment
When combined development with a magenta color developer using Red 122 was performed, the bluish and reddish colors were strong, respectively.
No clear green or orange color was obtained.

Comparative Example 2 The procedure of Example 1 was repeated, except that 5.0 parts of the monoazo yellow pigment produced in Production Example 6 was used instead of 5.0 parts of the monoazo pigment composition produced in Production Example 1. The same components as in Example 1 were kneaded, pulverized and classified in the same manner as in Example 1 to obtain a toner having an average particle diameter of 10 μm, and 1.0% by weight of hydrophobic silica (Aerosil R-972) was mixed with the toner. This was a one-component yellow magnetic toner.

Using this one-component yellow magnetic toner,
When development was carried out using the same dry-type plain paper copier as described above, a clear yellow image as obtained in Example 1 was not obtained.

Further, C.I. I. Pigment Yellow
When development was performed in combination with a cyan developer using ow 15: 3, a strong bluish color was not obtained and a clear green color was not obtained.

C. I. Pigment Red 122
When the development was carried out in combination with a magenta color developer using, a strong reddish color and a clear orange color could not be obtained.

Table 1 below summarizes the above examples and comparative examples.

Table 1 Preparation of Developer and Results of Development Test ────────────────────────── Monoazo Pigment Composition Development Test Results ────実 施 Example 1 Production Example 1 ◎ Comparative Example 1 Production Example 5 △ to ○ Comparative Example 2 Production Example 6 × Example 2 Production Example 2 ◎ ────────────────────────── [Development test results] ：: good clarity, good color reproducibility △: good clarity, Poor color reproducibility ×: Poor clarity, poor color reproducibility

As is clear from Table 1, the composition of Example 1 was obtained from C.I. I. Pigment Yellow 74 and C.I. I. Pigment Yellow 203, and C.I. I. Pigment Yellow 74 on the primary particle surface. I. Pigment
Since the yellow 203 is uniformly adsorbed or contained in the crystal structure, as in the composition of Comparative Example 1,
C. I. Pigment Yellow 74 and C.I. I. Pigment Yellow 203, or a mixture of C.I.
I. It can be seen that superior characteristics were obtained as compared with the case where Pigment Yellow 74 was used alone.

[0073]

The pigment composition of the present invention has excellent heat resistance, and when used as an electrostatic developing toner for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like. When used in combination with cyan toner and magenta toner, it is possible to provide a toner for electrostatic charge development having excellent color reproduction.

Claims (4)

[Claims] The present invention comprises two or more monoazo pigments (X), and at least a part of the pigments (xn + 1), (xn + 2)... Is uniformly adsorbed on the surface of the primary particles of the pigment (xn). Or a pigment composition for a toner for developing an electrostatic image, wherein the pigment composition is contained in a crystal structure. 2. The method according to claim 1, wherein the monoazo pigment (X) is a pigment (xn). I. Pigment Yellow 74 and pigment (xn +
1), (xn + 2) ... a monoazo pigment obtained by reacting a diazonium salt of an aniline compound other than a diazonium salt of 2-methoxy-4-nitroaniline with 2-methoxyacetoacetic acid arylamide. Pigment composition. 3. The pigment composition according to claim 1, wherein two or more of the monoazo pigments (X) are produced simultaneously. 4. An electrostatic charge developing toner comprising the pigment composition according to claim 1, 2 or 3.