JP2002012784A - Pigments and toners for electrostatic charge development - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To be excellent in transparency and coloring power and to receive a high heat history.
Yellow that can be used in applications and has little impact on the environment during decomposition
Get the pigment. The disazo pigment is represented by the following formula 1 or 5:
Disazo pigments which are
An electrostatic charge developing toner containing a pigment. Equation 1 Embedded image [In the formula 1, n = 1 to 4, and R1, R2, R3 and R4
Is independently CH_Three, C_TwoH _Five, OCH_Three, OC_TwoH_Five, N
O_Two, Cl. ] Embedded image [Wherein n = 1 to 4, R1, R2, R3 and R4
Is independently H, CH_Three, C_TwoH_Five, OCH_Three, OC_TwoH_Five, N
O_Two, Cl. ]

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel azo pigment used as a coloring material, and further develops an electrostatic image in electrophotography, electrostatic recording, electrostatic printing, etc. using the same. And a color toner.

[0002]

2. Description of the Related Art Disazo yellow pigments have long been used as coloring agents for printing inks, paints, plastics, etc. due to their high coloring power and high productivity. In recent years, it has been disclosed in US Pat. No. 3,345,293 and JP-A-49-109040 that it can be used for a color toner for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like.
No. JP-A-63-046470, JP-B-58-042
462 and the like.

[0003] However, disazo yellow pigments do not always have sufficient heat resistance.
When used in plastic molded products that have undergone a melt-kneading process, transparency and tinting strength are often reduced.

Further, C.I. I. Pigment Yellow
Dichlorobenzidine (3, 3 ′) represented by W 12 etc.
-Dichloro-4,4'-diaminobiphenyl) -based cisazo yellow pigment may generate dichlorobenzidine due to decomposition during heating, and its use has been restricted in recent years from the viewpoint of safety. For this reason, various studies have been conducted on pigments in which the diamine moiety is replaced with another substance in place of dichlorobenzidine.

In order to prevent such adverse effects, Japanese Patent Laid-Open Publication No.
No. 6,38,354 discloses a bisdiazonium salt such as 1,2-bis- (2-amino-phenoxy) -ethane.
Disazo compounds (CI Pigmen) obtained by coupling an acetoacetate amino-amide compound such as acetoacetylamino-benzimidazolone in a molar ratio of 1: 2.
t YELLOW 180).

[0006]

However, as described in JP-A-56-38354, C.I. I.
Pigment YELLOW 180 has a performance that can be sufficiently used even in an application that receives a high heat history, but has a drawback that the transparency and coloring power of an image are insufficient.

[0007] The problem to be solved by the present invention is that it has a higher transparency and coloring power, and has a performance capable of sufficiently using even a color toner which undergoes a high heat history, for example, a heat-setting process. It is intended to provide a disazo yellow pigment which is excellent in productivity and has little effect on the environment at the time of decomposition, and a color toner using the same.

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have succeeded in substituting the C.I.P. by replacing the benzimidazolone ring corresponding to the terminal of the pigment structure with another structure. I. Pigment
It has been found that while maintaining the excellent performance of YELLOW 180, it is possible to exhibit more excellent transparency and coloring power.

That is, as the pigment, a disazo pigment synthesized from a diamine compound represented by the formula 2 and an acetoacetic acid arylamide compound represented by the formulas 3 and 4 or a diazo compound represented by the formula 6 and the formulas 7 and 8 Disazo pigments synthesized from the acetoacetic acid arylamide compounds shown in the above are excellent in transparency and coloring power, have sufficient heat resistance against advanced heat history, and The inventors have found that the present invention is excellent, and have completed the present invention.

That is, the present invention provides the following inventions. 1. The disazo pigment is a disazo pigment represented by the following formula 1.

Embedded image Wherein R1, R2, R3 and R4 are independently
CH ₃ , C ₂ H ₅ , OCH ₃ , OC ₂ H ₅ , NO ₂ , and Cl are shown. ]

2. A bisdiazonium salt (A) of a diamine compound represented by the following formula 2, and the following formulas 3 and 4
2. A disazo pigment having the structure of the above 1, wherein the azoacetic acid arylamide compound (B) or (C) is reacted with

Embedded image

Embedded image

Embedded image [However, in Formula 2, n represents 1-4, and Formula 3 and Formula 4
Wherein R1, R2, R3 and R4 are independently CH ₃ , C ₂ H
₅ , OCH ₃ , OC ₂ H ₅ , NO ₂ , and Cl. ]

3. A disazo pigment represented by the following formula 5:

Embedded image Wherein R1, R2, R3 and R4 are independently
H, CH ₃ , C ₂ H ₅ , OCH ₃ , OC ₂ H ₅ , NO ₂ , Cl
Is shown. ] 4. The structure according to the above 3, wherein the bisdiazonium salt (D) of a diamine compound represented by the following formula 6 is reacted with the acetoacetic arylamide compounds (E) and (F) represented by the following formulas 7 and 8. Disazo pigments.

Embedded image

Embedded image

Embedded image [However, in Formula 6, n represents 1-4, Formula 7 and Formula 8
Among, R1, R2, R3 and R4 are independently, H, CH _3,
C ₂ H ₅ , OCH ₃ , OC ₂ H ₅ , NO ₂ , and Cl are shown. ]

5. An electrostatic charge developing toner comprising the pigment according to any one of the above 1 to 4.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The pigment of the present invention comprises a disazo pigment composed of the disazo compounds of the above formulas 1 and 5, a disazo compound having a structure obtained by reacting a bisdiazonium salt of a diamine compound with an acetoacetic acid arylamide compound. Hereinafter, Expressions 1 to 8 are omitted.

As long as this disazo compound has the above-mentioned structure, its production method is not particularly limited. For example, a bisdiazonium salt of a diamine compound (A) and an acetoacetic arylamide compound (B ) And (C).

The bisdiazonium salt (A) or (D) of the diamine compound of the present invention refers to a bisdiazonium salt of a diamine compound represented by the formula (2) or (6). This bisdiazonium salt (A) or (D) can be obtained, for example, by reacting a diamine compound with hydrochloric acid and sodium nitrite.

For obtaining the bisdiazonium salt (A) of a diamine compound usable in the present invention, for example, the following diamine compounds can be used. Bis- (2-amino-phenoxy) -methane bis- (3-amino-phenoxy) -methane bis- (4-amino-phenoxy) -methane 1,2-bis- (2-amino-phenoxy) -ethane 1, 2-bis- (3-amino-phenoxy) -ethane 1,2-bis- (4-amino-phenoxy) -ethane 1,3-bis- (2-amino-phenoxy) -propane 1,3-bis- ( 3-Amino-phenoxy) -propane 1,3-bis- (4-amino-phenoxy) -propane 1,4-bis- (2-amino-phenoxy) -butane 1,4-bis- (3-amino-phenoxy ) -Butane 1,4-bis- (4-amino-phenoxy) -butane

In order to obtain a bisdiazonium salt (D) of a diamine compound, for example, the following diamine compounds can be used. Bis- (2-amino-phenoxy) -methane 1,2-bis- (2-amino-phenoxy) -ethane 1,3-bis- (2-amino-phenoxy) -propane 1,4-bis- (2- Amino-phenoxy) -butane

On the other hand, as the acetoacetic arylamide compounds (B) and (C), acetoacetic arylamide compounds having the structures represented by Formulas 3 and 4 can be used. For example, the following are mentioned. 3-oxo-N-phenyl-butanamide, N- (2-
Methylphenyl) -3-oxo-butanamide, N-
(3-methylphenyl) -3-oxo-butanamide,
N- (4-methylphenyl) -3-oxo-butanamide, N- (2-methoxyphenyl) -3-oxo-butanamide, N- (3-methoxyphenyl) -3-oxo-butanamide, N- (4- Methoxyphenyl) -3-
Oxo-butanamide, N- [2- (acetylamino)
Phenyl] -3-oxo-butanamide, N- [3-
(Acetylamino) phenyl] -3-oxo-butanamide, N- [4- (acetylamino) phenyl] -3-
Oxo-butanamide, N- (2-chlorophenyl)-
3-oxo-butanamide, N- (3-chlorophenyl) -3-oxo-butanamide, N- (4-chlorophenyl) -3-oxo-butanamide, N- (2,4-
Dimethylphenyl) -3-oxo-butanamide, N-
(2-methyl-3-chlorophenyl) -3-oxo-butanamide, N- (2-methyl-4-chlorophenyl)
-3-oxo-butanamide,

As the acetoacetic arylamide compounds (E) and (F), acetoacetic arylamide compounds having the structures represented by the formulas 7 and 8 can be used. For example, the following are mentioned. N- (2-methylphenyl) -3-oxo-butanamide, N- (3-methylphenyl) -3-oxo-butanamide, N- (4-methylphenyl) -3-oxo-butanamide, N- (2- Methoxyphenyl) -3-oxo-butanamide, N- (3-methoxyphenyl) -3
-Oxo-butanamide, N- (4-methoxyphenyl) -3-oxo-butanamide, N- [2- (acetylamino) phenyl] -3-oxo-butanamide, N
-[3- (acetylamino) phenyl] -3-oxo-
Butanamide, N- [4- (acetylamino) phenyl] -3-oxo-butanamide, N- (2-chlorophenyl) -3-oxo-butanamide, N- (3-chlorophenyl) -3-oxo-butanamide, N- (4-
Chlorophenyl) -3-oxo-butanamide, N-
(2,4-dimethylphenyl) -3-oxo-butanamide, N- (2-methyl-3-chlorophenyl) -3-
Oxo-butanamide, N- (2-methyl-4-chlorophenyl) -3-oxo-butanamide,

In the above combination of the bisdiazonium salt and the acetoacetic arylamide compound, the molar ratio is 1: 2.
By performing a known and commonly used diazo coupling reaction, the desired disazo pigment can be obtained. This reaction is carried out, for example, under acetic acid acid, at pH 3 to 9, at a temperature of 5 to 30 ° C.
After performing for 10 minutes to 300 minutes, the temperature is 80 to 9 minutes.
It can be carried out by keeping the temperature at 5 ° C. and holding for 1 to 5 hours.

The reaction slurry containing the disazo pigment thus obtained can be used as a monoazo pigment as it is, and can be isolated and used as a wet pigment through filtration and washing steps, and further isolated as a dry pigment by drying and grinding. Can be used. Further, the obtained wet pigment or dry pigment can be further dispersed in a solvent, subjected to heat treatment in the solvent, and then isolated and used.

In the present invention, each mol% of the acetoacetic arylamide compound is not particularly limited with respect to 1 mol of the diamine compound bisdiazonium salt. Desirably, the total number of moles of the acetoacetate arylamide compound is preferably from 1.995 to 2.300 per mole of the diamine compound bisdiazonium salt.

In the present invention, a combination of the acetoacetic arylamide compounds (B) and (C) or (E)
In the combination of (F) and (F), the same structure or different structure can be used. The constituent molar ratio of acetoacetic arylamide (B) / (C) and the constituent molar ratio of (E) / (F) are not particularly limited.

If the pigment of the present invention has the same other structure, a pigment having a nitrogen atom bonded to the 2-position is more heat-resistant and transparent than a pigment having a nitrogen atom bonded to the 3- or 4-position. It is preferred in terms of. Among them, among those represented by Formula 5, a pair of R1 and R2 (left) and R3 and R4 in the formula
When the pair (right) is asymmetric, the sharpness is higher and the color reproducibility is better. Further, if other structures are the same, as the atomic groups of R1 to R4 defined in the present invention, a bulkier atomic group has more excellent transparency and coloring power.

As described above, the yellow disazo pigment of the present invention can be synthesized by a conventionally known synthesis method. If necessary, a conventionally known additive such as rosin and a surfactant may be added before and after the synthesis of the disazo yellow pigment composition to synthesize the disazo yellow pigment composition.

The pigment composition of the present invention can be used for various printing inks such as lithographic inks and gravure inks, various paints such as baking paints and air-dried paints, colored molded articles such as polyolefin and polyurethane molded articles, and colored molded articles. Charge image developing toner,
Any known and commonly used applications such as high-tech applications such as jet inks and color filters can be used. However, the pigment composition of the present invention is used for applications that receive a high thermal history, for example, a colored molded article of a high melting point thermoplastic resin such as polyphenylene sulfide or polybutylene terephthalate,
To the toner for developing electrostatic images through the heat set fixing process,
It can be suitably used.

The color toner of the present invention includes a one-component color toner containing a magnetic substance in the color toner (color toner for magnetic one-component development) and a non-magnetic one-component color toner containing no magnetic substance (non-magnetic one-color toner). (A color toner for component development) or a color toner for a two-component developer mixed with a carrier (color toner for two-component development).

The one-component magnetic toner is, for example, a colorant, a binder resin, a magnetic powder, a charge control agent (CCA), and other additives typified by a mold release agent. Can be configured.

The amount of the colorant used in the present invention in the color toner is not particularly limited.
It is preferably used in an amount of 0.5 to 25 parts by weight with respect to 0 parts by weight, and 2 to 15 parts by weight with respect to 100 parts by weight of the binder resin from the viewpoint that the charging performance of the colorant itself becomes more remarkable.
More preferably, it is part by weight.

As the binder resin used in the color toner of the present invention, any of known and commonly used resins can be used.
Any of natural resins, synthetic resins, natural rubbers, synthetic rubbers, synthetic waxes, and the like that exhibit adhesiveness under the application of heat or pressure 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 color toner of the present invention include polyvinyl chloride, polyacetal resin, polyamide, polycarbonate, polystyrene, polyacrylonitrile, polypropylene, polyethylene, fluorine resin, polyurethane, epoxy resin, and the like. Silicone resin, polyester, melamine resin, urea resin, phenolic resin, methacrylic resin,
An acrylic resin, an alkyd resin, a vinyl resin, a copolymer formed from each monomer component of these resins, an aliphatic or alicyclic hydrocarbon resin, an aromatic petroleum resin, a chlorinated paraffin, a paraffin wax and the like can be mentioned.

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 color 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 in view of their transparency and the hue of the toner.

The feature of the pigment of the present invention, which is excellent in transparency, is that it leads to an effect that a clear image with good color development can be obtained, particularly in the field of full-color toner in which a color image is formed by superimposing toners of each color. is there.

The magnetic powder used in the color toner of the present invention is not particularly limited, but it is preferable to use a magnetic powder that does not easily affect its reproduced color. Iron, yellow γ-iron oxide, iron oxide such as ferrite; iron, cobalt, metals such as nickel, or these metals and aluminum, cobalt,
Copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese,
Alloys with metals such as selenium, titanium, tungsten, vanadium, poly-1,4-bis (2,2,6,6,-
Organic magnetic substances such as tetramethyl-4-oxyl-4-piperidyl-1-oxyl) butadieneporphyrin metal complex, and mixtures thereof, and the like. Of these, yellow γ-iron oxide is particularly preferred from the viewpoint 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 viewpoints of charging stability and hue.

The color toner of the present invention further comprises various plasticizers, resistance adjusters and charge control agents for adjusting the thermal, electrical and physical properties of the toner, if necessary, in addition to the above components. May be.

Examples of the plasticizer include dibutyl phthalate and dioctyl phthalate. Examples of the resistance adjuster include tin oxide, lead oxide and antimony oxide. Examples of the charge control agent include quaternary ammonium salts and pyridinium salts. Examples thereof include metal dyes.

Further, in the present invention, after the production of the toner particles, fine powder such as TiO ₂ , Al ₂ O ₃ , SiO ₂ or the like is added to the toner particles to improve the fluidity of the toner, or to obtain zinc stearate, phthalic acid or the like. May be added to prevent deterioration of the photoconductor.

The color 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, a two-roll, a three-roll, or a heating kneader, cooled, stirred by a pulverizer such as a jet mill, and classified by an air classifier, and the present invention. Is obtained. The particle size of the color toner of the present invention is 5 to 5.
15 μm is preferred.

When used as a two-component color developer color toner, the same colorants, binder resins, and other additives as described above for the one-component color magnetic toner can be used.

Further, as the carrier used in the color toner of the present invention, for example, iron powder, nickel powder, ferrite powder, glass beads, or styrene-acrylate copolymer, styrene- Methacrylic acid ester copolymer, acrylic acid ester polymer, methacrylic acid ester polymer, silicone resin, polyamide resin, ionomer resin, polyphenylene sulfide resin, etc. or a mixture of these resins can be used. Those having a range of 50 to 300 μm are preferred.

A color toner for a two-component color developer can be obtained by frictionally mixing these carrier particles and the color toner of the present invention with a horizontal cylindrical or V-shaped container rotating mixer.

The mixing ratio of the carrier and the color toner can be generally used in the range of 2 to 10 parts by weight of the color toner with respect to 100 parts by weight of the carrier in order to obtain an appropriate image density. -6 parts by weight.

Next, embodiments of the present invention will be described based on preferred embodiments. The yellow disazo pigment is obtained by reacting a diamine compound bisdiazonium salt solution with a suspension composed of a mixture of an acetoacetate arylamide compound, heating, if necessary, filtering, washing with water, drying, and pulverizing. .

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 pigment composition, and 40 to 1 per part by weight
20 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, crushed and classified, and a dry powder color toner for developing an electrostatic charge image having a volume average particle diameter of 5 to 15 μm. Get.

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 obtain magnetic or non-magnetic particles. A dry powder color toner for developing an electrostatic charge image for magnetic one-component development.

When the above-mentioned 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 above-mentioned toner to prepare a developer.

[0052]

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 1,2-bis- (2-aminophenoxy) -ethane 10
Parts were stirred and dispersed in 250 parts of water while stirring 24% of 35% hydrochloric acid in 24 parts.
Parts were added. After stirring for 1 hour, 15 parts of 40% sodium nitrite was added in an ice bath to carry out a diazotization reaction. After stirring for one hour or more, to remove excess nitrite ions, 4.4 parts of sulfamic acid was added, and the mixture was stirred for 10 minutes or more to prepare a bisdiazonium salt solution.

On the other hand, 15.2 parts of 3-oxo-N-phenyl-butanamide were added to 350 parts of water, and 25
% Caustic soda was added and dissolved by stirring. In this,
16.7 parts of 90% acetic acid was added over 1 hour at room temperature to precipitate a coupler. Further, 20% caustic soda was added thereto to adjust the pH to 6.0. 2 internal temperature in ice bath
While maintaining the temperature at 0 ° C., the bisdiazonium salt solution was added for 3 hours.
The reaction was added over time to perform a coupling reaction. At this time, a 20% caustic soda solution was added dropwise to adjust the coupling pH in the system to always be 6.0.

After completion of the coupling, the mixture was 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 disazo yellow pigment according to the present invention.

Preparation Example 2 Preparation Example 1 except that 16.4 parts of N- (2-methylphenyl) -3-oxo-butanamide was used instead of 15.2 parts of 3-oxo-N-phenyl-butanamide. To produce a disazo yellow pigment.

Production Example 3 Production was carried out except that 17.6 parts of N- (2,4-dimethylphenyl) -3-oxo-butanamide was used instead of 15.2 parts of 3-oxo-N-phenyl-butanamide. A disazo yellow pigment was prepared according to Example 1.

Production Example 4 3-oxo-N-phenyl-butanamide 1 was replaced with 15.2 parts of 3-oxo-N-phenyl-butanamide 1
A disazo yellow pigment was prepared according to Preparation Example 1, except that 3.7 parts and 1.64 parts of N- (2-methylphenyl) -3-oxo-butanamide were used.

Production Example 5 3-oxo-N-phenyl-butanamide 1 was replaced with 15.2 parts of 3-oxo-N-phenyl-butanamide 1
A disazo yellow pigment was prepared according to Preparation Example 1, except that 3.7 parts and 1.77 parts of N- (2-methoxyphenyl) -3-oxo-butanamide were used.

Preparation Example 6 Instead of 15.2 parts of 3-oxo-N-phenyl-butanamide, 15.9 parts of N- (2,4-dimethylphenyl) -3-oxo-butanamide and N- (2-methoxy A disazo yellow pigment was produced according to Production Example 1, except that 1.77 parts of phenyl) -3-oxo-butanamide were used.

Production Example 7 Instead of 15.2 parts of 3-oxo-N-phenyl-butanamide, 8.8 parts of N- (2,4-dimethylphenyl) -3-oxo-butanamide and N- (2-methoxy A disazo yellow pigment was prepared according to Preparation Example 1, except that 8.9 parts of phenyl) -3-oxo-butanamide were used.

Production Example 8 1,2-bis- (2-aminophenoxy) -ethane 10
1,2-bis- (4-aminophenoxy)-
A disazo yellow pigment was produced according to Production Example 1, except that 10 parts of ethane were used.

Production Example 9 1,2-bis- (2-aminophenoxy) -ethane 10
A disazo yellow pigment was produced according to Production Example 1, except that 10.3 parts of 3,3′-dichloro-4,4′-diaminobiphenyl were used instead of parts.

Production Example 10 1,2-bis- (2-aminophenoxy) -ethane 10
A disazo yellow pigment was produced according to Production Example 3, except that 10.3 parts of 3,3'-dichloro-4,4'-diaminobiphenyl were used instead of parts.

Production Example 11 1,2-bis- (2-aminophenoxy) -ethane 10
A disazo yellow pigment was produced according to Production Example 4, except that 10.3 parts of 3,3'-dichloro-4,4'-diaminobiphenyl were used instead of parts.

[0066]

[Table 1]

Example 1 [Production of Color Toner] Styrene-acrylic acid copolymer (Hymer SBM100, manufactured by Sanyo Chemical Industries, Ltd.) 100.0 parts Disazo yellow pigment produced in Production Example 1 5.0 parts After kneading with an extruder, the mixture was pulverized and classified with a jet mill to obtain a toner having an average particle diameter of 10 μm, and hydrophobic silica (Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) was added to the toner.
0% was mixed to obtain a yellow toner for two-component development.

[Evaluation of Color Toner] A two-component developer was prepared by mixing this yellow toner for two-component development with a commercially available ferrite carrier for developer. Using this developer, a dry plain paper copier (Recopy FT3010,
(Developed by Ricoh Co., Ltd .; the same shall apply hereinafter)). As a result, a clear yellow image free from background fog was obtained even on the 5000th copy (evaluation: ○).

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 color developer using No. 22, a clear red color was reproduced.

Comparative Example 1 The procedure of Example 1 was repeated, except that 5.0 parts of the disazo yellow pigment produced in Production Example 8 was used instead of 5.0 parts of the disazo yellow pigment produced in Production Example 1. The same components as in Example 1 were kneaded, crushed 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 yellow toner for two-component development.

A developer was similarly prepared using this yellow toner for two-component development, and development was performed using the same dry-type plain paper copier as described above. As a result, the yellow color was as sharp as obtained in Example 1. No image was 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 was not obtained.

Examples 2 to 7, Comparative Examples 2 to 4 In place of the disazo yellow pigments prepared in Production Example 1, the disazo yellow pigments shown in Table 2 were used, and toners and developers were prepared according to Example 1. did.

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 2.

[0077]

[Table 2]

[Results of Developing Test] ：: Very good clarity, very good color reproducibility ：: Good clarity, good color reproducibility △: Slightly good, poor color reproducibility ×: Poor clarity, color reproducibility Bad

As is clear from Table 2, the disazo yellow pigment composition of the present invention has improved heat resistance, so that a clear image can be obtained from a developer using the disazo yellow pigment composition. Since the disazo yellow pigment or the pigment composition obtained by the method had poor heat resistance, an image obtained from a developer using the disazo yellow pigment or the pigment composition was unclear.

Further, a developer using the monoazo yellow pigment composition according to the present invention; I. Pigment Ye
Combination with cyan developer using C.l.low 15: 3, C.I. I. When combined development with a magenta developer using Pigment Red 122 was performed, clear green and red were reproduced in each of the examples.

On the other hand, a developer using a monoazo yellow pigment or a pigment composition obtained by a conventionally known method; I. Pigment Yellow 15:
Combination with cyan developer using C.3, C.I. I.
When combined development with a magenta color developer using Pigment Red 122 was performed, blue and red were strong, and clear green and red were not obtained.

[0082]

The disazo yellow pigment of the present invention has a particularly remarkable effect that superior heat resistance can be imparted as compared with conventional disazo pigments.

Further, since this pigment has excellent heat resistance and excellent safety during thermal decomposition, it can be used as a color for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like. When used as a toner, it is possible to provide a color toner that is excellent in clarity and excellent in color reproduction when used in combination with a cyan toner and a magenta toner.

Claims (5)

[Claims] (1) a disazo pigment represented by the following formula (1):
Disazo pigments that are sazo compounds. Formula 1[In the formula 1, n = 1 to 4, and R1, R2, R3 and R4
Is independently CH_Three, C_TwoH _Five, OCH_Three, OC_TwoH_Five, N
O_Two, Cl. ] 2. The structure according to claim 1, wherein the bisdiazonium salt (A) of a diamine compound represented by the formula 2 is reacted with the acetoacetic arylamides (B) and (C) represented by the formulas 3 and 4. Disazo pigments. Formula 2 Formula 3 Formula 4 [In the formula 2, n is 1 to 4, and in the formulas 3 and 4, R1,
R2, R3 and R4 are _{independently, CH 3, C 2 H 5} , OC
H ₃ , OC ₂ H ₅ , NO ₂ , and Cl are shown. ] 3. A disazo pigment wherein the disazo pigment is a disazo compound represented by the following formula 5. Formula 5 [Wherein n = 1 to 4, R1, R2, R3 and R4
Independently represent H, CH ₃ , C ₂ H ₅ , OCH ₃ , OC ₂ H ₅ , N
O ₂ and Cl are shown. ] 4. The structure according to claim 3, wherein the bisdiazonium salt (D) of a diamine compound represented by the formula (6) is reacted with the acetoacetic arylamides (E) and (F) represented by the formulas (7) and (8). Disazo pigments. Formula 6 Formula 7 Formula 8 [In the formula 6, n is 1 to 4, and in the formulas 7 and 8, R1,
R2, R3 and R4 are _{independently, H, CH 3, C 2} H 5, O
CH ₃ , OC ₂ H ₅ , NO ₂ , and Cl are shown. ] 5. An electrostatic charge developing toner containing the pigment according to claim 1.