JPH11272014A - Magenta color toner and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a toner having good light resistance, triboelectric property and dispersibility and excellent brightness, chroma and especially transparency by using a specified monoazo pigment having the average graininess in a specified range in the cumulative volume distribution. SOLUTION: The average graininess D50 of the monoazo pigment expressed by the formula in the cumulative volume distribution satisfies 0.05 μm<=D50<=0.2 μm. In the formula, the substituent R is 1-4C alkyl group. The monoazo pigment for a magenta color toner is produced by mixing a diazonium soln. containing a diazonium salt and a coupler soln. containing a coupler which causes coupling reaction with the diazonium salt. In the coupling reaction, an anionic surfactant is added to the coupler soln. The anionic surfactant is selected from alkylbenzene sulfonates, naphthalene sulfonate-formalin condensates or mixture of these. The add amt. is preferably 0.5 to 5 wt.% of the monoazo pigment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magenta color toner used in a full-color copying machine or the like, and more particularly, to developing an electrostatic image in an electrophotographic method, an electrostatic recording method, an electrostatic printing method or the like. Color toner used for this purpose.

[0002]

2. Description of the Related Art As a method of forming a visible image by developing an electric latent image with a color toner, an electrostatic charge printing method, an electrophotographic method and the like have hitherto been known. With these methods,
An electric latent image is formed on a photoconductive photoreceptor by various means, and then the latent image is developed with a toner to obtain a visible image, or, if necessary, a powder or the like on paper or the like. Is generally fixed by heating, pressurizing or solvent vapor to obtain a visible image. In particular,
First, a color original is irradiated with light to obtain a multicolor image of color, the reflected light is separated into three primary colors of light using a color separation filter, and the light is irradiated onto the surface of the photosensitive drum, thereby obtaining an electrical image. Form a latent image. A color toner such as magenta, cyan, and yellow is sequentially transferred to the obtained electric latent image to form a toner image, which is pressed and heated to be fixed, thereby obtaining a multicolor superimposed visible image. be able to.

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

In the above-described conventional electrophotographic method, a magenta color toner is used as one of the color toners.
Examples of the magenta pigment used in this toner include quinacridone pigments disclosed in JP-A-49-46951 and JP-A-51-144625, and JP-A-59-970.
No. 49, for example, disclosed in JP-A-63-1.
For example, thioindigo pigments disclosed in No. 29352 and the like and anthraquinone pigments disclosed in JP-A-1-217465 and the like are known, and various magenta color toners are prepared using these pigments.

[0005]

However, various physical and chemical properties are required for the color toner, and the above-mentioned conventional magenta color toner does not satisfy all of these physical and chemical properties. In fact, no satisfactory magenta color toner has yet been obtained. The characteristics required for the magenta color toner include the following. Good spectral reflection characteristics, high transparency so that multicolor superposition is possible, and so that transmitted light of the OHP sheet is not scattered;
Good dispersibility in the binder resin, stable triboelectric charging characteristics in various environments, and good light resistance.

The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide light resistance, triboelectrification and good dispersibility, lightness, chroma, In particular, it is to provide a magenta color toner having excellent transparency.

[0007]

The present invention relates to a magenta color toner containing a monoazo pigment represented by the following formula (3) or (4) as a pigment for a magenta color toner used in electrophotography or the like. The average particle size D50 according to the cumulative volume distribution is 0.05 μm ≦ D50 ≦ 0.2 μm
Are based on the fact that the above-mentioned required characteristics can be satisfied.

[0008]

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[0009]

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Here, in the chemical formulas 3 and 4, the substituent R
Represents an alkyl group having 1 to 4 carbon atoms.

The particle size in the present specification is based on the volume average diameter, and is expressed as the average particle size D50 at which the cumulative volume distribution becomes 50%.

The monoazo pigments of Chemical Formulas 3 and 4 are produced by mixing a diazonium solution containing a diazonium salt and a coupler solution containing a coupler for performing a coupling reaction with the diazonium salt. Here, a coupler refers to a compound that generates an azo compound by a coupling reaction with a diazonium salt. In the present invention, during the coupling reaction, an anionic surfactant is added to the coupler solution, and the coupling reaction is performed using the coupler solution,
The monoazo pigments of Chemical Formulas 3 and 4 having an average particle size in the above range are obtained. The addition amount of the anionic activator is preferably 0.5 to 5% by weight based on the monoazo pigment. When the addition amount of the anionic surfactant is less than 0.5% by weight, the effect of adding the anionic surfactant is not substantially obtained, and D50 is not more than 0.5%.
A tendency to become larger than 2 μm appears. If the content is more than 5% by weight, the D50 tends to be smaller than 0.05 μm.

The method for producing a monoazo pigment according to the present invention is characterized in that a diazonium solution containing a diazonium salt and a coupler solution containing a coupler for performing a coupling reaction with the diazonium salt are mixed to form a monoazo pigment for magenta color toner. An anionic surfactant is added to the coupler solution during the coupling reaction. As the anionic surfactant, one selected from the group consisting of an alkylbenzene sulfonate, a naphthalene sulfonate formalin condensate, and a mixture thereof is used.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The magenta color toner of the present invention contains a monoazo pigment represented by Chemical Formula 3 or 4 as a pigment, and has an average particle size D50 based on a cumulative volume distribution of:
0.05 μm ≦ D50 ≦ 0.2 μm.

When the average particle size D50 according to the cumulative volume distribution is 0.
If it is larger than 2 μm, the amount of light passing through the pigment particles is reduced, the transparency is reduced, and the color reproducibility of a multicolor superimposed visible image is significantly impaired. Also,
On an OHP sheet, transmitted light is scattered and darkened, resulting in a light transmission image of low saturation, which is not preferable. On the other hand, when the average particle size D50 is smaller than 0.05 μm, the aggregation of the pigment particles increases, and the dispersion in the binder resin becomes extremely difficult,
It is not preferable because it is difficult to obtain a clear color image.

The compounds of the formulas 3 and 4 can usually be obtained as follows. That is, an aromatic amine is diazotized according to a conventional method to obtain a diazonium solution in the same manner as in a conventionally known method for producing a monoazo pigment. Separately, a coupler component to be subjected to a coupling reaction with a diazonium salt is prepared according to a conventional method to obtain a coupler solution. And
By mixing both the diazonium solution and the coupler solution and causing a coupling reaction between the diazonium salt and the coupler component, pigments of Chemical Formulas 3 and 4 can be obtained. The average particle size D50 of the present invention is 0.05 μm ≦ D50 ≦ 0.2
The μm pigment can be obtained by previously adding an anionic activator to the above coupler solution and performing a coupling reaction.

In the present invention, the anionic activator that can be used is not particularly limited.
Resin acid salt, fatty acid salt, alkyl sulfate salt, alkyl aryl sulfonate, alkyl naphthalene sulfonate, dialkyl sulfonate, polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl phosphate, polyoxyethylene glycerol Examples thereof include fatty acid ester salts and naphthalene sulfonate formalin condensates. Among them, (A) an alkylbenzene sulfonate, (B) a naphthalene sulfonate formalin condensate, and a mixture thereof are preferably used.

Anionic activators, especially component (A) and / or
Alternatively, the pigment prepared using the component (B) has good compatibility with the binder resin at the time of forming the toner. In addition, in the production of a pigment, in a coupling reaction with a diazonium salt in an acidic diazonium solution, a coupler component is precipitated as fine particles and the reaction proceeds, which is effective in making the pigment finer.

More specifically, as the component (A), Minerite 100 and 200 manufactured by Kyoeisha Chemical Co., Ltd., and Neopellex F-25 manufactured by Kao Corporation No. Examples of the component (B) include SN Dispersant 41 manufactured by San Nopco Co., Ltd., Solvalite C-45 manufactured by Kyoeisha Chemical Co., Ltd., and Demol N, RN, T manufactured by Kao Corporation.

The amount of the anionic surfactant added is preferably 0.5 to 5% by weight based on the weight of the pigment.

In the above chemical formulas 3 and 4, compounds in which the substituent R is a methyl group, that is, pigments represented by the following chemical formulas 5 and 6 are more preferable.

[0022]

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[0023]

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The pigment represented by Chemical Formula 5 is CI Pigment Red
The pigment corresponding to 238, and the pigment represented by Chemical formula 6 corresponds to ClPigment Red 147. Chemical 5
The pigments of Chemical formula 6 are known substances as compounds, and it has been found that when these compounds are used as pigments for color toners for electrophotography, the above-mentioned required characteristics (1) to (4) become better.

When the content of the monoazo pigment is 2 to 25 parts by weight with respect to 100 parts by weight of the magenta color toner, the above-mentioned required characteristics (1) and (2) become better.

The magenta color toner of the present invention contains a binder resin as a well-known constituent component in addition to the above-mentioned monoazo pigment, and further includes a charge control agent, a fluidizing agent, an abrasive, a charge improver, and a cleaning improver. It is common to use an agent or the like as an additive.

As the binder resin suitable for the color toner of the present invention, any known binder resin can be used. For example, homopolymers of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene and the substituted styrene are used. Styrene-vinyl naphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-
Octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-
Acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid Copolymer, styrene-
Styrene polymers such as maleic acid ester copolymers,
Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene,
Polypropylene, polyester, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, pentel resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. Can be used alone or as a mixture. Among them, a polyester resin is particularly preferably used in terms of transparency and mechanical strength.

There are two types of charge control agents, a positive charge control agent and a negative charge control agent. Examples of the positive charge control agent include a nigrosine dye and a quaternary ammonium salt. For example, a salicylic acid-based metal complex, an azo-based chromium complex, or the like is used.

As the fluidizing agent, fine particles of metal oxides such as silica, alumina, and zirconia, and those fine particles can be used as a silane coupling agent, a titanate coupling agent, a zircoaluminate, a quaternary ammonium salt, a fluorine-based activator. Surface-treated or coated with a treating agent such as a solvent, a polymer, or the like is used.

When a carrier is used for the developer, a conventionally known carrier can be used. For example, magnetic materials such as iron, cobalt, and nickel, alloys and mixtures thereof, and coatings on the surfaces thereof.

Next, a general method for producing the magenta color toner of the present invention will be described. First, the above-mentioned monoazo pigment and binder resin (charge control agent if necessary) are sufficiently stirred and mixed in a ball mill, and then melt-kneaded in a hot roll mill. Then, after cooling to room temperature, the obtained kneaded material is pulverized and classified to obtain a magenta color toner having a particle size of 1 to 20 μm.

[0032]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. In the following examples, “parts” is based on weight (parts by weight) unless otherwise specified.

(Production Example 1) 50 g (0.21 mol) of 3-amino-4-methoxybenzanilide was added to 1000 g of water.
, And add ice to set the temperature to 0-5 ° C.
60 g (0.58 mol) of 35% HCl aqueous solution was added and 2
Stirred for 0 minutes. Then, 30% aqueous sodium nitrite solution 5
After adding 0 g (0.22 mol) and stirring for 60 minutes, 2 g (0.02 mol) of sulfamic acid was added to eliminate nitrous acid. Further, 50 g (0.37 mol) of sodium acetate and 75 g (1.12 mol) of 90% acetic acid were added to obtain a diazonium salt solution.

Separately, 68 g (0.21 mol) of N- (5-chloro-2-methoxyphenyl) -3-hydroxy-2-naphthalenecarboxamide was added to 1000 parts of water.
g, 25 g of caustic soda (0.63 mol) at a temperature of 80
At 100 ° C. or lower, and as a component (A), Minerite 100
Was added (3.49% by weight based on the pigment) to obtain a coupler solution.

This solution is added to the above diazonium salt solution under a temperature condition of 10 ° C. or less, and a coupling reaction is carried out.
A heat treatment at 90 ° C. was performed. Next, after filtration and washing with water, drying was performed at 100 ° C., and pulverization was performed. This was used as a particle size distribution measuring device (trade name, CAPA-700: manufactured by Horiba, Ltd.)
As a result, about 117 g (0.20 mol) of a pigment of Chemical Formula 5 having an average particle size D50 by a cumulative volume distribution of 0.06 μm was obtained.

(Production Example 2) 40 g (0.17 mol) of 3-amino-4-methoxybenzanilide was added to 1000 g of water.
, And add ice to set the temperature to 0-5 ° C.
55 g (0.53 mol) of 35% HCI aqueous solution was added and 2
Stirred for 0 minutes. Then, a 30% aqueous solution of sodium nitrite 3
After adding 9 g (0.17 mol) and stirring for 60 minutes, 2 g (0.02 mol) of sulfamic acid was added to eliminate nitrous acid. Further, 41 g (0.30 mol) of sodium acetate and 60 g (0.90 mol) of 90% acetic acid were added to obtain a diazonium salt solution.

Separately, 53 g (0.17 mol) of N- (5-chloro-2-methylphenyl) -3-hydroxy-2-naphthalenecarboxamide was added to 1000 g of water,
It was dissolved at a temperature of 80 ° C. or lower together with 20 g (0.50 mol) of caustic soda, and 5.0 g (based on pigment, 2.31% by weight) of SN Dispersant 41 was added as a component (B) to obtain a cupper solution.

This solution was added to the above diazonium salt solution under a temperature condition of 10 ° C. or lower, and a coupling reaction was carried out.
A heat treatment at 90 ° C. was performed. Next, after filtration and washing with water, drying was performed at 100 ° C., and pulverization was performed. Production Example 1
When the particle size distribution was measured in the same manner as in Example 1, the average particle size D50 was found to be 0.
Approximately 91 g (0.16 mol) of the pigment of Chemical formula 6, which was 08 μm, was obtained.

(Comparative Production Example 1)
(A) Except that the addition of the mineralite 100 was omitted, the same conditions and the same operation as in Production Example 1 were carried out to obtain an average particle size D50.
Of about 0.28 μm was obtained (0.19 mol).

(Comparative Production Example 2)
(A) The same conditions and the same operations as in Production Example 1 were carried out except that 27 g of neoperex F-25 (based on the pigment, 5.87% by weight) was used instead of Minerite 100 as the component, and the average particle size D50 was 0.04 μm. About 115 g of pigment
(0.20 mol).

(Comparative Production Example 3)
Except that the addition of the SN dispersant 41 of the component (B) was omitted, the same conditions and the same operation as in Production Example 1 were carried out, and about 89 g (0.16 g) of a pigment having an average particle size D50 of 0.29 μm was obtained.
Mol).

(Comparative Production Example 4)
The same conditions and the same operation as in Production Example 2 were carried out except that 7.5 g of Demol N (based on pigment, 8.15% by weight) was used instead of the SN dispersant 41 as the component (B), and the average particle size D50 was 0.1%. Approximately 92 g (0.1 μm)
6 mol).

Table 1 summarizes the results of Production Examples 1 to 6.

[0044]

[Table 1]

(Example 1) With respect to the pigment of Production Example 1, a mixture having the composition shown in Table 2 below was stirred and mixed using a ball mill, then melt-kneaded with a hot roll mill, cooled, pulverized and classified. A fine powder of １８18 μm was obtained. To this fine powder, 0.5 part of silica as an additive was mixed and stirred to obtain a magenta toner.

[0046]

[Table 2]

Ferrite carrier (resin coat with a mixture of styrene-acrylic copolymer and vinylidene fluoride polymer) on 10 parts of this magenta color toner 19
0 parts were mixed to obtain a developer.

Using this developer, copying was performed with a dry plain paper electrophotographic copying machine (trade name, NP-5000: manufactured by Canon Inc.).
It was a vivid magenta color with excellent color developability. The transmitted image of the copied OHP sheet had a clear and vivid color tone. Further, the spectral reflection characteristics required for the magenta color were excellent. Table 3 shows the evaluation results.

[0049]

[Table 3]

When the charge amount of the toner was measured, the initial charge amount was -20.8 μc / g, and the charge amount of the toner after continuous copying of 10,000 sheets was −19.2 μc / g.
g, little difference from the initial charge amount was observed, and stable frictional charging characteristics were exhibited.

Xenon weather meter (trade name, SC
(750-WN: manufactured by Suga Test Instruments Co., Ltd.), it was found that no fading was observed after irradiation for 40 hours, and there was no problem with light resistance.

Example 2 A magenta color toner having a particle size of 5 to 15 μm was prepared by using the mixture having the composition shown in Table 2 and performing the same operation as in Example 1 for the pigment of Production Example 2. . The same ferrite carrier as in Example 1 was added to this toner to obtain a developer.

When copying was performed in the same manner as in Example 1 using this developer, the obtained image was a magenta color with a clear color tone excellent in transparency, dispersibility, and coloring. Also,
The transmitted image of the copied OHP sheet had a clear and vivid color tone. Further, the spectral reflection characteristics required for the magenta color were excellent. Table 3 shows the evaluation results.

When the charge amount of the toner was measured, the initial charge amount was -20.5 .mu.c / g, and the charge amount of the toner after continuous copying of 10,000 sheets was -19.1 .mu.c / g.
g, little difference from the initial charge amount was observed, and stable frictional charging characteristics were exhibited.

Comparative Example 1 As shown in Table 2, Production Example 1
The monoazo pigments of Comparative Production Example 1 (CI
Pigment Red 238, average particle size D50 = 0.28 μm), and the same operation was performed under the same conditions as in Example 1 to prepare and evaluate a magenta toner having a particle size of 5 to 16 μm.

Because of the large particle size of the pigment, the resulting image was inferior in lightness and chroma, particularly in transparency, and was magenta with poor coloring. Table 3 shows the evaluation results.

Comparative Example 2 As shown in Table 2, Production Example 1
In place of the pigment of Comparative Example 2, the monoazo pigment (Cl
Pigment Red 238, average particle size D50 = 0.04 μm), and the same operation was performed under the same conditions as in Example 1 to prepare and evaluate a magenta toner having a particle size of 6 to 14 μm.

Since the dispersibility of the pigment was inferior, the obtained image was inferior in lightness and chroma, and was magenta with poor coloring. Table 3 shows the evaluation results.

Comparative Example 3 As shown in Table 2, Production Example 2
The monoazo pigment of Comparative Production Example 3 (CI
Pigment Red 147, average particle size D50 = 0.29 μm), and the same operation was performed under the same conditions as in Example 2 to prepare and evaluate a magenta toner having a particle size of 5 to 16 μm.

Because of the large particle size of the pigment, the resulting image was inferior in lightness and saturation, particularly in transparency, and was magenta with poor coloring. Table 3 shows the evaluation results.

Comparative Example 4 As shown in Table 2, Production Example 2
The monoazo pigment of Comparative Production Example 4 (CI
Pigment Red 147, average particle size D50 = 0.04 μm), and the same operation was performed under the same conditions as in Example 2 to prepare and evaluate a magenta toner having a particle size of 6 to 16 μm.

Since the dispersibility of the pigment was inferior, the obtained image was inferior in lightness and chroma, and had a magenta color with poor coloring. Table 3 shows the evaluation results.

Comparative Example 5 As shown in Table 2, Production Example 1
Quinacridone pigments (ClPigment Re
d 122 Trade name: Fastogen Super Magenta RE 03 manufactured by Dainippon Ink and Chemicals, average particle size D50 = 0.12 μm)
The same operation was performed under the same conditions as in Example 1 except that magenta toner having a particle diameter of 4 to 16 μm was prepared and evaluated.

The obtained image was a magenta color having a hue shifted to the red side and a considerably poor chroma, and a low color developability, as compared with Examples 1 and 2. Table 3 shows the evaluation results.

[0065]

According to the magenta color toner of the present invention, the monoazo pigment was sufficiently dispersed in the resin and the dispersibility was good. Further, the magenta color toner of the present invention has good spectral reflection characteristics, and exhibits stable triboelectric charging characteristics in various environments. Furthermore, it has good light fastness, excellent transparency and color development, has a clear color tone, and is capable of multi-color superposition.

Claims (11)

[Claims] 1. A magenta color toner containing a monoazo pigment represented by the following formula 1, wherein the average particle size D50 according to the cumulative volume distribution of the monoazo pigment is 0.05.
A magenta color toner characterized in that μm ≦ D50 ≦ 0.2 μm. Embedded image (In the chemical formula 1, the substituent R is an alkyl group having 1 to 4 carbon atoms.) 2. A magenta color toner containing a monoazo pigment represented by the following formula 2, wherein the average particle size D50 of the monoazo pigment according to the cumulative volume distribution is 0.05.
A magenta color toner characterized in that μm ≦ D50 ≦ 0.2 μm. Embedded image (In the chemical formula 2, the substituent R is an alkyl group having 1 to 4 carbon atoms.) 3. The monoazo pigment is produced by mixing a diazonium solution containing a diazonium salt and a coupler solution containing a coupler that performs a coupling reaction with the diazonium salt, wherein the coupler solution is The magenta color toner according to claim 1, further comprising an anionic surfactant. 4. The amount of the anionic surfactant added is:
4. The magenta color toner according to claim 3, wherein the content of the monoazo pigment is 0.5 to 5% by weight. 5. The method according to claim 3, wherein the anionic surfactant is selected from the group consisting of an alkylbenzene sulfonate, a naphthalene sulfonate formalin condensate, and a mixture thereof. Magenta color toner. 6. The magenta color toner according to claim 1, wherein the substituent R is a methyl group. 7. The magenta color toner according to claim 1, wherein the content of the monoazo pigment is 2 to 25 parts by weight based on 100 parts by weight of the magenta color toner. . 8. A method for producing a monoazo pigment for a magenta color toner, wherein a diazonium solution containing a diazonium salt is mixed with a coupler solution containing a coupler coupled to the diazonium salt, wherein the coupler is provided. A method for producing a monoazo pigment for a magenta color toner, wherein the solution contains an anionic surfactant. 9. The addition amount of the anionic surfactant is as follows:
9. The method for producing a monoazo pigment for a magenta color toner according to claim 8, wherein the proportion of the monoazo pigment is 0.5 to 5% by weight based on the monoazo pigment. 10. The magenta according to claim 9, wherein the anionic surfactant is selected from the group consisting of an alkylbenzene sulfonate, a naphthalene sulfonate formalin condensate, and a mixture thereof. A method for producing a monoazo pigment for a color toner. 11. The method for producing a monoazo pigment for a magenta color toner according to claim 8, wherein the substituent R is a methyl group.