JP2001249498A - Toner for developing electrostatic images - Google Patents

Abstract

(57) [Problem] To provide a magenta toner having a small particle size, a narrow particle size distribution, and a pigment having a small particle size and being uniformly dispersed. SOLUTION: The polymerized toner for developing an electrostatic image, which comprises at least a binder resin and a colorant, comprises a compound represented by the following general formula (I) as a colorant. . Embedded image (In Formula I, A, B, and C are aromatic rings that may have a substituent.)

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magenta toner for developing an electrostatic image used in a dry toner of an electrophotographic copying machine or the like.

[0002]

2. Description of the Related Art Copiers and printers using electrophotography, especially full-color copiers and printers that reproduce multicolor images by superimposing a plurality of color toners, have rapidly become widespread. Images are being demanded. Requirements for a toner for obtaining a high-definition image include a small particle size, uniform particle size and chargeability, and good color reproducibility. In order to obtain a toner having a small particle size and a narrow particle size distribution, a pulverization method manufactured by mixing a polymer with a colorant, a charge control agent, etc., melt-kneading with an extruder, etc., and then pulverizing and classifying Compared with the polymerizable monomer, a colorant, a charge control agent, etc. are mixed, and then the suspension is subjected to suspension polymerization. The emulsion polymerization aggregation method produced by mixing a control agent dispersion and the like and then aggregating them is superior.

In order to impart a more uniform chargeability and good color reproducibility to a small particle size toner obtained by a suspension polymerization method or an emulsion polymerization aggregation method, a colorant, a charge control agent, etc. Need to be uniformly dispersed with a small particle size. In the suspension polymerization method, a colorant is mixed with a polymerizable monomer, and then the polymerizable monomer is subjected to suspension polymerization to produce a toner. Therefore, in order to uniformly disperse the colorant having a small particle diameter in the toner, it is necessary that the colorant has high dispersibility in the polymerizable monomer. When the toner is manufactured by the emulsion polymerization aggregation method, since the colorant is mixed in a dispersion state, the first condition is that the colorant can be processed into a dispersion with little change over time in the selection of the colorant. In order to obtain uniform chargeability and good color reproducibility, it is necessary to be able to process into a colorant dispersion liquid having a small particle diameter and a narrow particle size distribution, giving a toner in which a colorant having a small particle diameter is uniformly dispersed. . Also,
It is important for the color toner that the spectral reflection characteristics be good. Even if the colorant can be dispersed in a small particle size, if the spectral reflection characteristics are not good, a problem occurs in color reproducibility, which is not preferable. In particular, for magenta toner, it was not always satisfactory to achieve both color reproducibility and high-definition images.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art.
That is, an object of the present invention is to provide a magenta toner having good color reproducibility and obtaining a high-definition image.

[0005]

Means for Solving the Problems The inventors of the present invention have made intensive studies in view of the above-mentioned problems, and as a result, when obtaining a polymerized toner for developing an electrostatic image comprising at least a binder resin and a colorant, the polymer has a specific structure. The inventors have found that the above problems can be solved by using a magenta colorant, and have reached the present invention. That is, the gist of the present invention is to provide an electrostatic charge image developing polymer toner comprising at least a binder resin and a colorant, wherein the compound represented by the following general formula (I) is contained as a colorant. Exists in polymerized toner for development.

[0006]

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(In the formula I, A, B and C are aromatic rings which may have a substituent.) In a magenta colorant, a diazonium salt is reacted with a coupler which performs a coupling reaction with the diazonium salt. Monoazo pigments obtained by such methods are industrially advantageous in that they can be easily produced and various variations can be obtained, and thus have been widely used. Therefore, if this can be used for the emulsion polymerization aggregation method, it is very effective for producing a magenta toner for high definition images.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The toner for developing electrostatic images of the present invention contains a compound represented by the following general formula (I) as a colorant. It can also be used in combination with a good coloring agent. The mixing ratio of the compound represented by the general formula (I) and the other compound can be selected in the range of 100: 0 to 5:95. However, in order to achieve color reproducibility and a high definition image, The ratio of the compound represented by the formula (I) is preferably 30% or more, more preferably 50% or more.

[0009]

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(In the formula I, A, B and C are aromatic rings which may have a substituent.)

The amount of the colorant added is 2 to the binder resin.
A range of 25 parts by weight is preferred. In the general formula (I),
A, B, and C each represent an aromatic ring such as a benzene ring, a naphthalene ring, an anthracene ring, or a phenanthrene ring. Of these, a benzene ring or a naphthalene ring is preferable, and A is a benzene ring; Preferably, the ring, C, is a benzene ring. Further, in the general formula (I), an aromatic ring (A, B,
Examples of the substituent in C) include a halogen atom, a nitro group, a cyano group, a hydrocarbon group, an alkoxy group, an alkylthio group, an amino group, an amino group which may be substituted on a nitrogen atom, and a substitution on a nitrogen atom. Aminocarbonyl group, an aminosulfonyl group which may be substituted on the nitrogen atom, an alkylsulfonyl group, an alkoxysulfonyl group, and the like, and usually include stable substituents. Those having 12 to 300 are preferred.
Among these substituents, a halogen atom, a nitro group, a cyano group, a hydrocarbon group having 5 or less carbon atoms, an alkoxy group having 5 or less carbon atoms, an aminosulfonyl group which may be substituted on a nitrogen atom, or a nitrogen atom An aminocarbonyl group which may be substituted on the top is more preferred. More specifically, a compound represented by the following general formula (II) can be preferably used. These compounds are advantageous in production.

[0012]

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(In the formula II, R ¹ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydrocarbon group having 5 or less carbon atoms, R ² and R ³ each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydrocarbon group having 5 or less carbon atoms, an alkoxy group having 5 or less carbon atoms, a nitrogen atom Represents an optionally substituted aminosulfonyl group or an aminocarbonyl group optionally substituted on a nitrogen atom, provided that an aminosulfonyl group optionally substituted on a nitrogen atom or substituted on a nitrogen atom At least one aminocarbonyl group which may be
Have one. )

The substituent on the nitrogen in the aminosulfonyl group optionally substituted on the nitrogen atom or the aminocarbonyl group optionally substituted on the nitrogen atom includes phenyl, tolyl and the like. Alkyl group such as aryl group, methyl group, ethyl group, 1-propyl group, 1-butyl group, aralkyl group such as benzyl group, aryl group substituted with halogen atom or alkoxy group, substituted with halogen atom or alkoxy group. And an alkyl group. Further, in the general formula (II), R ¹ is a methoxy group, R ² is a hydrogen atom, R ³ is a phenylaminocarbonyl group, R ⁴ is a methoxy group, R ⁵ is a hydrogen atom, Using a compound in which R ⁶ is a chlorine atom, that is, a compound represented by the following formula (III):
It is preferable in terms of spectral reflection characteristics, dispersibility in a polymerizable monomer, and processability into a colorant dispersion.

[0015]

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The polymerized toner of the present invention comprises at least the above colorant and a binder resin, and is produced not by a so-called pulverization method but by a dispersion polymerization method such as a suspension polymerization method or an emulsion polymerization method. It is. When the toner for developing an electrostatic image of the present invention is obtained by the emulsion polymerization aggregation method, the compound represented by the formula (I) is usually used in the form of a dispersion. This dispersion can be easily prepared by adding a compound represented by the formula (I) to a water together with a surfactant, and using a mechanical pulverization method containing a medium or the like. Surfactants include nonionic surfactants represented by polyoxyethylene alkyl phenyl ethers, anionic surfactants represented by alkylbenzene sulfonates, and cationic surfactants represented by quaternary ammonium salts. However, it is preferable to use polyoxyethylene styryl ether or dodecylbenzene sulfonate. Further, a water-soluble organic solvent may be added as needed.
The dispersion diameter is 0.001 to 1.5 μm, preferably 0.0
It is in the range of 1 to 1 μm. Although it is not clear why the compound represented by the formula (I) can be easily dispersed by the above-mentioned method, these compounds have a hydroxyl group on the B ring, and even if a small amount of a dispersing agent, the compound has a small particle size and a narrow particle size distribution. It is considered that this contributes to the ability to be obtained and to obtain a dispersion liquid with little change over time.

When the toner for developing an electrostatic image of the present invention is obtained by the emulsion polymerization aggregation method, the binder resin used is in the form of an emulsion. When the toner for developing an electrostatic charge image of the present invention is obtained by a suspension polymerization method, a polymer is obtained by mixing a polymerizable monomer with a colorant, a charge control agent, and the like, and then performing suspension polymerization.
In any case, the binder resin can be selected from a wide range including those conventionally known. Preferably, a styrene-based polymer such as a styrene-acrylate copolymer, a styrene-methacrylate copolymer, or an acrylic acid copolymer of these resins, a saturated or unsaturated polyester-based polymer, and an epoxy-based polymer are exemplified. be able to. Further, the binder resin is not limited to being used alone, and may be used in combination of two or more kinds. As a method for producing a binder resin emulsion, for example, a method for producing by emulsion polymerization,
A method in which the binder resin is dissolved in a water-soluble or water-insoluble organic solvent, and then added to water and emulsified is used. Also,
A binder resin emulsion containing wax can also be used.

A charge controlling agent may be added to the electrostatic image developing toner of the present invention in order to impart a charge amount and charge stability. Known compounds are used as the charge control agent.
Examples thereof include metal complexes of hydroxycarboxylic acids, metal complexes of azo compounds, naphthol compounds, metal compounds of naphthol compounds, nigrosine dyes, quaternary ammonium salts, and mixtures thereof. Preferably, a compound represented by the following general formula (IV) or a metal salt thereof is used.

[0019]

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(In the formula IV, D, E, F, and G each represent an aromatic ring which may have a substituent. X represents a divalent bonding group or a direct bond.) , E, F, and G include, for example, a benzene ring, a naphthalene ring, a phenanthrene ring, and an anthracene ring. Preferably, D and E are a naphthalene ring, and F and G are a benzene ring. . When these aromatic rings have a substituent, the substituent is preferably a halogen atom, a nitro group, a cyano group, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. , F and G are more preferably halogen atoms. X is a divalent linking group, specifically, a divalent hydrocarbon group such as a methylene group, an ethylene group, a 1,3-propylene group, an isopropylidene group, an ethylidene group, a sulfur atom, an oxygen atom, Examples thereof include a sulfonyl group, a sulfo group, and a carbonyl group. A divalent hydrocarbon group is preferable, and a methylene group is more preferable.

A wax may be added to the electrostatic image developing toner of the present invention for imparting releasability. Any wax can be used as long as it has a releasing property. Specifically, carnauba wax, vegetable wax such as rice wax, solid silicone wax such as alkyl denatured silicone, amide wax such as stearamide, higher fatty alcohol wax, higher fatty ester wax, polyethylene, polypropylene And a mixture thereof. Preferably, an ester wax having a long-chain aliphatic group, more preferably, behenyl behenate or stearyl stearate is used. The amount of wax added is 5 in either the suspension polymerization method or the emulsion polymerization aggregation method.
Since a large amount of −30 parts can be added, a large amount may be added as necessary.

When the toner for developing an electrostatic image of the present invention is obtained by the emulsion polymerization aggregation method, the charge control agent and the wax are used in the form of a dispersion. These can be obtained as follows. For example, each substance is a nonionic surfactant represented by polyoxyethylene alkyl phenyl ether, an anionic surfactant represented by alkylbenzene sulfonate, and a cationic surfactant represented by quaternary ammonium salt. It can be easily prepared by adding a surfactant and the like to water and using a mechanical pulverization method containing a medium and the like. Further, a water-soluble organic solvent may be added as necessary. The dispersion diameter of each substance is 0.001 to
It is in the range of 5 μm, preferably 0.01-1 μm.

In the emulsion polymerization coagulation method, a colorant dispersion, a charge control agent dispersion, a wax dispersion, and the like are mixed with a polymer emulsion, and the mixture is coagulated by appropriately controlling the temperature, salt concentration, pH, and the like. To manufacture. The toner particle size is usually in the range of 2 to 10 μm, preferably 3 to 8 μm, and more preferably 4 to 7 μm. The obtained toner usually has a surface active agent and the like remaining on the surface. For this purpose, acid washing, alkali washing, water washing and the like are appropriately performed to remove the surfactant, and the resulting toner is subjected to filtration and drying. A toner is obtained.

In the suspension polymerization method, a colorant,
A charge controlling agent, wax and the like are mixed and subjected to a dispersion treatment using a disperser such as a disperser, and the monomer composition after the dispersion treatment is dispersed in a water-miscible medium using an appropriate stirrer. After granulating to a diameter, the polymerizable monomer is polymerized to produce a toner. The compound represented by the formula 1 can be easily and uniformly dispersed in the polymerizable monomer by a dispersion treatment. The toner particle size is usually in the range of 2 to 10 μm, preferably 3 to 8 μm, and more preferably 4 to 7 μm.

When a suspension stabilizer is used, it is preferable to select a neutral or alkaline one which can be easily removed by washing the toner after the polymerization with acid. Further, it is preferable to select a toner capable of obtaining a toner having a narrow particle size distribution. Suspension stabilizers that satisfy these requirements include calcium phosphate, tricalcium phosphate, magnesium phosphate, calcium hydroxide, magnesium hydroxide and the like. Each can be used alone or in combination of two or more. These suspension stabilizers can be used in an amount of 1 to 10 parts by weight based on the radical polymerizable monomer. As the polymerization initiator, known polymerization initiators can be used alone or in combination of two or more. For example,
Use potassium persulfate, 2,2'-azobisisobutyronitrile, 2,2'-azobisiso (2,4-dimethyl) valeronitrile, benzoyl peroxide, lauroyl peroxide, or redox initiator Can be.

After producing the toner by the above method, a toner having a capsule structure is produced by adding a polymer emulsion, a colorant dispersion, a charge control agent dispersion, a wax dispersion and the like to coat the toner surface. be able to. A known external additive may be added to the toner for developing an electrostatic image of the present invention in order to control fluidity and developability. As the external additive, various kinds of inorganic oxide particles such as silica, alumina, titania and the like (which may be subjected to a hydrophobic treatment if necessary), vinyl polymer particles and the like can be used. The amount of the external additive is preferably in the range of 0.05 to 5 parts by weight based on the toner particles. The electrostatic image developing toner of the present invention can be developed by a known developing method. For example, cascade method, magnetic brush method, two-component developing method such as microtoning method, conductivity,
It can be used for any of the insulating one-component developing method and the non-magnetic one-component developing method.

[0027]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited to the following Examples without departing from the scope of the invention. (Preparation of Colorant Dispersion) a) Colorant Dispersion A 160 g of demineralized water and 5 g of an alkylbenzene sulfonate as a dispersant were added to 40 g of the compound of the formula (III), and the mixture was dispersed for 5 hours by a sand grinder mill and averaged. A colorant dispersion A having a particle size of 0.18 microns was obtained. B) Colorant Dispersion B (Comparative Colorant Dispersion) Pigment Red 48: 250 g in 150 g of demineralized water,
7.6 g of an alkylbenzene sulfonate was added as a dispersant, and the mixture was subjected to a dispersion treatment with a sand grinder mill for 5 hours to obtain a comparative colorant dispersion B having an average particle size of 0.20 μm.

C) Colorant Dispersion C (Comparative Colorant Dispersion) In the preparation of the above colorant dispersion A, C.I. I. Pigment Red 5
Except that 7: 1 was used, the production of a colorant dispersion was attempted in exactly the same way, but the toner could not be produced because it was gelled and could not be obtained as a dispersion. D) Colorant Dispersion D (Comparative Colorant Dispersion) Except for adding 12 g of polyoxyethylene alkylphenyl ether instead of alkylbenzene sulfonate as a dispersant in the preparation of Colorant Dispersion C described above. When an attempt was made to prepare a colorant dispersion, it was gelled and could not be obtained as a dispersion, and thus a toner could not be prepared.

(Synthesis of Binder Resin Emulsion) 2.2 kg of an ester wax emulsion having a solid content of 30% and 26 kg of demineralized water were placed in a reactor and heated to 90 ° C., and 6 g of dodecylbenzenesulfonate, 5 kg of styrene, n 1.3 kg of butyl acrylate, 186 g of acrylic acid, 25 g of divinylbenzene, 31 g of trichlorobromomethane, 656 g of an 8% aqueous hydrogen peroxide solution, 65% of an 8% ascorbic acid aqueous solution 65
6 g were added. The reaction was continued at 90 ° C. for 7 hours to obtain a binder resin emulsion comprising a styrene acrylic polymer. (Preparation of Charge Control Agent Dispersion) To 40 g of 4,4'-methylenebis [2- [N- (4-chlorophenyl) amide] -3-hydroxynaphthalene], 160 g of demineralized water and 8 g of alkylnaphthalene sulfonate as a dispersant were added. The resulting mixture was dispersed by a sand grinder mill for 3 hours to obtain a charge control agent dispersion.

(Production of magenta toner) a) Magenta toner A 19 g of a colorant dispersion A was added to 300 g of the binder resin emulsion.
1.8 g of the charge control agent dispersion was mixed and stirred. Continue stirring
While 0.5% Al_Two(SO_Four)_Three79.4g
Was added and the temperature was raised to 60 ° C., and stirring was continued. The resulting particles
When the particle size was measured using a Coulter counter,
The volume average diameter was 7.6 microns. The resulting particles
Suction filtration and water washing are repeated, followed by air-drying.
60 g of Tatner A was obtained. B) Magenta Toner B (Comparative Magenta Toner) Comparative Colorant Dispersion B15
g and 1.8 g of the charge control agent dispersion were mixed and stirred. Stirring
While continuing, 0.5% Al_Two(SO_Four) _Three 9
0.8 g was added, the temperature was raised to 65 ° C., and stirring was continued. Obtained
The size of the particles was measured using a Coulter counter.
However, the volume average diameter was 8.5 microns. Obtained
The suctioned particles are repeatedly filtered and washed with water, followed by air drying.
Thus, 60 g of magenta toner B was obtained.

Example 1 0.03 g of hydrophobic silica was externally added to 50 g of magenta toner A, and a copy was made with a dry electrophotographic copying machine. The resulting image was visually observed to give a clear magenta color. there were. Table 1 shows the results of measuring the spectral reflectance by X-Rite938. Comparative Example 1 The same operation was performed under the same conditions as in Example 1 except that magenta toner B was used instead of magenta toner A. When the obtained image was visually observed, the color was much redder than the magenta color. Table 1 shows the results of measuring the spectral reflectance by X-Rite938.

[0032]

Table 1 L * a * b * Example 1 54.4 56.1-10.0 Comparative Example 1 56.5 62.1 8.5

[0033]

According to the present invention, a magenta toner having a small particle size, a narrow particle size distribution, and a pigment having a small particle size and being uniformly dispersed can be obtained. Further, since the magenta toner has a good spectral reflection characteristic, a full-color image with good color reproducibility and a clear color tone can be obtained by using this toner.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor ▲ Crane ▼ Masami Mori 1000 Kamoshitacho, Aoba-ku, Aoba-ku, Yokohama-shi, Kanagawa Prefecture Mitsubishi Chemical Corporation Yokohama Research Laboratory (72) Inventor Tokuaki Takahashi Kamoshita-cho, Aoba-ku, Yokohama-shi, Kanagawa 1000 address Mitsubishi Chemical Corporation Yokohama Research Laboratory F-term (reference) 2H005 AA21 AB06 CA21

Claims (4)

[Claims] 1. A polymerizable toner for developing an electrostatic image comprising at least a binder resin and a colorant, comprising a compound represented by the following general formula (I) as a colorant. toner. Embedded image (In Formula I, A, B, and C are aromatic rings that may have a substituent.) 2. A polymerizable toner for developing an electrostatic charge image, comprising at least a binder resin and a colorant, comprising a compound represented by the following general formula (II) as a colorant: toner. Embedded image (In Formula II, R ¹ , R ⁴ , R ⁵ , and R ⁶ each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydrocarbon group having 5 or less carbon atoms, or a hydrocarbon group having 5 or less carbon atoms. R ² and R ³ each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydrocarbon group having 5 or less carbon atoms, an alkoxy group having 5 or less carbon atoms, and a substituent on the nitrogen atom Represents an aminosulfonyl group which may be substituted or an aminocarbonyl group which may be substituted on a nitrogen atom, provided that an aminosulfonyl group or a nitrogen atom which may be substituted on a nitrogen atom Has at least one aminocarbonyl group in the molecule.) 3. In the general formula (II), R ¹ is a methoxy group, R ² is a hydrogen atom, R ³ is a phenylaminocarbonyl group, R ⁴ is a methoxy group,
3. The polymerized toner according to claim 2, wherein R ⁵ is a hydrogen atom and R ⁶ is a chlorine atom. 4. The polymerized toner for developing an electrostatic image according to claim 1, wherein the polymerized toner is obtained by mixing and aggregating at least a polymer emulsion and a colorant dispersion.