JP3370651B2 - Production method of ferrite particles containing azo charge control agent - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing ferrite particles containing an azo-based charge control agent, which prevents deterioration of image density and resolution in an electrophotographic copying method and generation of fog to improve transfer efficiency.

[0002]

2. Description of the Related Art At present, electrophotographic copying machines, which are becoming smaller and faster, are capable of enduring continuous operation for a long time under a bad environment of high temperature and high humidity and always producing stable and high quality clear images. Is required. Therefore, excellent environmental stability,
There is a need for an electrophotographic toner that has durability stability and proper density, is free from black spots, and is capable of copying images with high resolution. The conventional technique of preliminary dry mixing is to put a resin, a coloring agent such as magnetite or carbon black, a charge control agent such as a metal-containing dye, wax, etc. at a time into a mixer such as a Henschel mixer, and cool the rotary blades while cooling. Mix by changing the shape and the number of rotations. However, the resin, colorant,
Since the charge control agent and the wax have different particle diameters, specific gravities, and charging characteristics, it is difficult to uniformly disperse them. In order to solve this point, in JP-A-2000-137347, a binder resin, a colorant, a charge control agent and a wax are not put in a mixer at a time and reacted, but with an azo compound metal complex solution, Ferrite particles in which a charge control agent composed of an azo compound is uniformly contained are obtained by mixing an iron-containing salt and oxidizing iron in an alkaline aqueous solution, adding an acid to form an acidic solution, and then filtering.

[0003]

However, in the above-mentioned prior art, since the iron-containing salt is mixed and oxidized after forming the azo compound metal complex solution to form the azo-based charge control agent-containing ferrite, when the ferrite is oxidized. The azo-based charge control agent-containing ferrite containing the by-product generated in the above is produced. When ferrite contains a large amount of by-products, the purity of the ferrite is low, so that the toner particles are not uniformly and surely attached to the ferrite particles, and the toner particles are not conveyed well to the developing sleeve together with the ferrite particles. As a result, the image density and resolution are lowered and fog occurs, and the transfer efficiency is lowered. Therefore, it is an object of the present invention to provide a method for producing azo-based charge control agent-containing ferrite particles that enhances the purity of ferrite, prevents deterioration of image density and resolution, prevents fog from occurring, and enhances transfer efficiency.

[0004]

The method of producing ferrite particles containing an azo type charge control agent according to the present invention comprises mixing a salt containing iron, water or a solvent consisting of water and alcohol, and a hydroxide of an alkali metal. A step of oxidizing iron in the salt to form a reaction mixture containing ferrite and a by-product, a step of dissolving and removing the by-product in the reaction mixture in a solvent to extract ferrite, and a carboxyl compound, A step of adding a metal salt and a hydroxide of an alkali metal to ferrite to obtain a charge control agent-containing ferrite, and after diazotizing an aromatic primary amine, mixing and coupling a naphthol derivative, and coupling the solvent. To obtain a monoazo compound-containing solution, and the obtained charge control agent-containing ferrite is reacted with the monoazo compound-containing solution to produce an azo-based charge control agent-containing ferrite. And a degree. Since the azo-based charge control agent-containing ferrite particles are produced from the reaction mixture from which by-products such as sulfates have been removed, high-purity ferrite particles can be obtained, and a small amount of ferrite sufficiently exhibits the function as a colorant. Further, when the toner particles are conveyed to the magnetic roll, the toner particles adhere to the high-purity ferrite particles surely and uniformly, and it is possible to prevent the deterioration of the image density and the resolution and the occurrence of fog and improve the transfer efficiency. In another embodiment of the present invention, a step of mixing the extracted ferrite and a positive ion compound to obtain an ion ferrite, a carboxyl compound, a metal salt, and a hydroxide of an alkali metal are added to the ion ferrite. And a step of obtaining a charge control agent-containing ferrite. The method includes a step of uniformly mixing the ferrite and the charge control agent and forming particles having an average particle size of 1.0 μm or less in which the ferrite and the charge control agent are integrally attached. A step of purifying the azo-based charge control agent-containing ferrite is included.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the method for producing ferrite particles containing an azo type charge control agent according to the present invention will be described below. The method for producing the azo-based charge control agent-containing ferrite particles according to the present invention comprises first mixing a salt containing iron, a solvent consisting of water or water and an alcohol, and a hydroxide of an alkali metal to remove the iron in the salt. Oxidation by aeration causes ferrite (MO ・
Fe ₂ O ₃ ), and a reaction mixture containing by-products are produced.
Oxidation is performed at a temperature of 70 to 90 ° C. for 2 to 5 hours. The solvent alcohol is selected from methyl alcohol, ethyl alcohol, butyl alcohol, propyl alcohol, isopropyl alcohol and the like. Since the reaction mixture contains by-products in addition to ferrite, the by-products are dissolved in a solvent and removed. This decantation is repeated several times to extract highly pure ferrite.

Next, a carboxyl compound, a metal salt,
Water and an alkali metal hydroxide are added to ferrite and reacted for 1-2 hours to obtain a charge control agent-containing ferrite. The alcohol may be used instead of water. When alcohol is used as a solvent, various metal complex ions different from the case where only water is used as a solvent are formed, the viscosity is lowered, and the reaction is rapidly carried out. Further, the extracted ferrite and a positive ion compound are mixed to generate an ion ferrite, and a carboxyl compound, a metal salt, and a hydroxide of an alkali metal are added to the ion ferrite to obtain a charge control agent-containing ferrite. You may get it.

The metal of the metal salt is iron, chromium, nickel,
One or more selected from cobalt, tin, manganese, cerium, silver, zinc, magnesium, zirconium, beryllium, copper, aluminum, barium, calcium, titanium, indium, lithium and cadmium. Carboxyl compounds are salicylic acid, salicylic acid derivatives, naphthoic acid and naphthoic acid derivatives,
The derivative of salicylic acid is one or more selected from 3,5-ditertiarybutylsalicylic acid and 5- (5-t-octyl) salicylic acid, and the naphthoic acid derivative is 2-hydroxy-3-naphthoic acid. , Alkyl (C4-9) -2-hydroxy-3-naphthoic acid, 5,6,
7,8-Tetrahydro-2-hydroxy-3-naphthoic acid, alkyl (C4-9) -5,6,7,8-tetrahydro-2-hydroxy-3-naphthoic acid, 1-hydroxy-2-naphthoic acid 1 selected from acid, alkyl (C4-9) -1-hydroxy-2-naphthoic acid, 5,6,7,8-tetrahydro-1-hydroxy-2-naphthoic acid
Or two or more naphthoic acids.

The positive ion compound is one or more amines selected from butylamine, amylamine, octylamine, nonylamine, dimethylamine, dipropylamine, triethylamine, triallylamine, benzylamine and triethanolamine. The aqueous solvent is one or more alcohols selected from methyl alcohol, ethyl alcohol, butyl alcohol, propyl alcohol and isopropyl alcohol.

On the other hand, an aromatic primary amine was diazotized.
After that, the naphthol derivative is mixed and coupled to dissolve.
The agent is added to obtain a solution containing a monoazo compound. Aromatic first class
Amines are 5-nitro-2-aminophenol and 4,
Selected from 6-dinitro-2-aminophenol,
Futol derivatives include 2-naphthol and 3-hydroxy-
2-naphthoanilide and 3-hydroxy-2-naphtho-
p-anisijit (C _TenH₆(OH) CH₂C₆H_FourOC
H₃) Is selected from. Solvents are water, water and ethyl cello
Solve (C₂H_FiveOCH₂CH₂OH), water and ethylene
Recall, ethylene glycol, ethylene glycol and
And n-butyl alcohol, ethylene glycol and dime
Tyl sulfoxide, diethylene glycol, methyl cello
Solve (CH ₃OCH₂CH₂OH), dimethyl sulfoxide
It is selected from side as well as formamide. 5-nitro-
2-Aminophenol is diazotized and 2-naphthol is
In addition, a reaction example to obtain a monoazo compound by coupling
The chemical reaction formula is shown below. C₆H₃(NO₂) (OH) (NH₂) → C₆H₃(NO₂) (OH) (N
₂ ⁺) C₆H₃(NO₂) (OH) (N₂ ⁺) + C_TenH₇OH → C₆H₃(N
O₂) (OH) N₂C_TenH₆OH

An azo type charge control agent containing an azo type charge control agent represented by the following general formula (I) is obtained by reacting a charge control agent containing ferrite with a monoazo compound containing solution at 100 to 120 ° C. for 1 to 2 hours. Obtain the contained ferrite.

[0011]

[Chemical 1] (In the formula, R ₁ represents a hydrogen atom, a nitro group, a halogen atom, an amino group, an acetylamino group, a sulfamide group, a sulfomethyl group, a hydroxyl group, a methoxy group, an ethoxy group, a benzoylamino group (including a substituted benzoylamino group). , R ₂ represents a nitro group, a halogen atom, an alkyl group, an amino group, an acetylamino group, a sulfamido group, a sulfomethyl group, a hydroxyl group, a methoxy group, an ethoxy group, and R ₃ represents a hydrogen atom, a halogen atom, an alkyl group, an amino group. Represents an acetylamino group, a sulfoamido group, a sulfomethyl group, a hydroxyl group, a methoxy group, an ethoxy group, n represents 1 or 2, m represents an integer of 1 to 3. M represents iron, chromium, nickel, cobalt, tin,
Manganese, cerium, silver, zinc, magnesium, zirconium, beryllium, copper, aluminum, barium, calcium, titanium, indium, lithium, and cadmium. )

The obtained azo-based charge control agent-containing ferrite is purified by filtration, washing, drying and crushing. As a result, as shown in FIG. 1, the ferrite (2) and the charge control agent (3) were uniformly mixed, and the ferrite (2) and the charge control agent (3) were integrally adhered to each other to have an average particle size of 1.0 μm. The following ferrite particles (1) containing a charge control agent are obtained. Average particle size is 1.0 μm
Hereafter, it is preferably 0.01 μm or more. It is difficult to uniformly pulverize particles having an average particle size of less than 0.01 μm to produce the particles, and there is a drawback in that the dispersion of the particle size becomes large.

The obtained azo-based charge control agent-containing ferrite particles contain a charge control agent composed of an azo compound uniformly dispersed in the ferrite particles. Therefore, a toner using the toner can reduce image density and resolution and cause fog. Generation can be prevented and transfer efficiency can be improved.

As a raw material of the toner, a binder resin, a colorant such as magnetite or carbon black, a charge control agent such as a metal-containing dye, and a wax are used. The binder resin is polystyrene, styrene-acrylic acid copolymer, styrene-
Methacrylic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer,
From styrene resin such as styrene-butadiene copolymer, saturated polyester resin, unsaturated polyester resin, epoxy resin, phenol resin, maleic acid resin, coumarone resin, chlorinated paraffin, xylene resin, vinyl chloride resin, polypropylene and polyethylene It is one or more selected from the group consisting of

As the colorant, the charge control agent and the magnetic substance, azo type charge control agent-containing ferrite particles made of an azo compound are used. The content of the azo-based charge control agent-containing ferrite particles in the toner is 5 to 70%, preferably 25 to 55%. If the content of the azo-based charge control agent-containing ferrite particles is less than 5%, the magnetic force is weak and it cannot be carried on the magnetic roll, and toner scatters. If it exceeds 70%, the binder resin component is relatively Therefore, the fixing property of the toner on the transfer paper is deteriorated.

The wax is low molecular weight polypropylene, low molecular weight polyethylene, microcrystalline wax,
It is selected from carnauba wax, sazol wax, paraffin wax and aliphatic solid alcohol. If necessary, a fluidizing agent, a charging aid and an abrasive are added to the toner. Fine particles of silica, titanium oxide, alumina,
Silicon oil, silicon varnish, fine particles hydrophobized with a silane coupling agent, metal oxides such as calcium titanate, metal carbide, inorganic fine particles such as metal nitride, methyl methacrylate, polyvinylidene fluoride,
It is possible to use organic fine particles such as polystyrene and fine particles of organometallic compounds such as zinc stearate and calcium stearate.

The toner is sufficiently mixed with the binder resin, the azo type charge control agent-containing ferrite particles and the wax described above by a mixer such as a ball mill or a Henschel mixer, and then kneaded by a kneader such as a heat roll kneader or an extruder. Then
After cooling and solidification, it is manufactured by pulverization, classification and post-treatment (external addition). In addition, it can be obtained by a spraying method, a polymerization method, or the like.

[0018]

EXAMPLES Examples of a method for producing ferrite particles containing an azo type charge control agent according to the present invention will be described below together with comparative examples.
All formulations are parts by weight.

Example 1 <Synthesis of Ferrite Particles Containing Azo Charge Control Agent> A solution prepared by adding 3000 parts of ferrous sulfate to 4400 parts of water and dissolving it.
Mix 1000 parts of sodium hydroxide with 1500 parts of water and dissolve it, stir, and blow while blowing air 9
Oxidation reaction was carried out at 0 ° C. for 5 hours. Next, the obtained ferrite (FeO.Fe ₂ O ₃ ) particles were precipitated, the supernatant was discarded, and 3000 parts of water was added and stirred. Ferrite particles were precipitated again, the supernatant was discarded, decantation of adding water and stirring was repeated 7 times, sodium sulfate as a by-product was removed, and high-purity ferrite particles were extracted. 2 parts of sodium hydroxide in the extracted aqueous solution of ferrite particles,
Water (463 parts), chromium sulfate (2.5 parts) and 3,5-ditertiarybutylsalicylic acid (6.3 parts) were added, and the mixture was reacted at 90 ° C. for 1 hour to obtain a charge control agent-containing ferrite. Furthermore, 100 parts of ethylene glycol in which 7.8 parts of a monoazo compound obtained by reacting 5-nitro-2-aminophenol as a diazo component and 2-naphthol as an azo component were dissolved was added to the charge control agent-containing ferrite to obtain 100 parts. The reaction was carried out at 0 ° C. for 1 hour to obtain an azo type charge control agent-containing ferrite. Finally, after filtration, washing with water, drying at 120 ° C. for 6 hours, crushing, and azo-based charge control agent-containing ferrite particles having an average particle size of 0.3 μm and uniformly containing 1.0% of the azo-based charge control agent. 840 parts were obtained.

<Manufacture and Performance Confirmation of Toner> Styrene-acrylic ester copolymer 49 parts Low molecular weight polypropylene NP-505 (manufactured by Mitsui Petrochemical Co., Ltd.) 2 parts Azo-based charge control agent-containing ferrite particles 49 parts The above materials are mixed. After dry-mixing with a machine (Henschel mixer), the mixture was kneaded with a twin-screw kneader whose temperature was set to 130 ° C. The obtained kneaded product is cooled, coarsely pulverized to about 2 mm or less with a hammer mill, finely pulverized with a jet pulverizer having a coarse powder classification function, and classified with an air flow classifier to have an average particle size of 9.3 μm.
To obtain a raw toner of. To 100 parts of the obtained raw toner, 0.3 parts of hydrophobic colloidal silica and 1.0 part of calcium titanate were added and mixed with a mixer (Henschel mixer), and then aggregates were removed by a vibrating screen to obtain a toner. . This toner is a commercially available copier (product name: NP-400RE Canon Inc.)
As a result of conducting a continuous copying test on 10,000 sheets, the transfer efficiency was high as shown in Table 1, with no deterioration in image density and resolution, no fog.

Comparative Example 1 <Manufacture and Performance Confirmation of Toner> Styrene-acrylic ester copolymer 49 parts Low molecular weight polypropylene NP-505 (manufactured by Mitsui Petrochemical Co., Ltd.) 2 parts Ferrite (FeO.Fe ₂ O ₃ ). Particles 44.6 parts Charge control agent (azo chromium metal complex) 0.4 parts The above materials were dry-mixed with a mixer (Henschel mixer) and then kneaded with a twin-screw kneader having a temperature set at 130 ° C. The obtained kneaded product is cooled, coarsely pulverized to about 2 mm or less with a hammer mill, finely pulverized with a jet pulverizer having a coarse powder classification function, and classified with an air flow classifier to have an average particle size of 9.1 μm.
To obtain a raw toner of. To 100 parts of the obtained raw toner, 0.3 parts of hydrophobic colloidal silica and 1.0 part of calcium titanate were added and mixed with a mixer (Henschel mixer), and then aggregates were removed by a vibrating screen to obtain a toner. . This toner is a commercially available copier (product name: NP-400RE Canon Inc.)
As a result of a continuous copying test of 10,000 sheets, the image density and resolution were low, fog was generated frequently, and the transfer efficiency was low, as shown in Table 1.

Example 2 Synthesis of Ferrite Particles Containing Azo Charge Control Agent A solution prepared by adding 2640 parts of ferrous sulfate to 3870 parts of water and dissolving it.
880 parts of sodium hydroxide was mixed with 1320 parts of water and dissolved, and the mixture was stirred and blown with air.
The oxidation reaction was carried out at 5 ° C. for 6 hours. Next, the obtained ferrite (FeO.Fe ₂ O ₃ ) particles were precipitated, the supernatant was discarded, and 3000 parts of water was added and stirred. Ferrite particles were precipitated again, the supernatant was discarded, decantation of adding water and stirring was repeated 7 times, sodium sulfate as a by-product was removed, and high-purity ferrite particles were extracted. 40 parts of triethanolamine, which is a positive ion compound, was added to the extracted aqueous solution of ferrite particles, and the mixture was stirred for 10 minutes. 2 parts of sodium hydroxide, 450 parts of water, 2.0 parts of zinc chloride and 1.7 parts of acetic acid were added to the obtained ion ferrite aqueous solution.
Parts were added and reacted at 90 ° C. for 1 hour to obtain a charge control agent-containing ferrite. On the other hand, 4500 parts of 6% hydrochloric acid was added to 13.8 parts of a monoazo compound obtained by reacting 4,6-dinitro-2-aminophenol as a diazo component with 3-benzoylamino-2-naphthol as an azo component. Stirring, filtration and water washing were performed. This monoazo compound was added to a mixed solution of 50 parts of water and 70 parts of ethyl cellulob, and a charge control agent-containing ferrite was further added, followed by reacting at 120 ° C. for 2 hours to obtain an azo type charge control agent-containing ferrite. Finally, after filtering and washing with water, it was dried at 120 ° C. for 6 hours, pulverized, and azo-based charge control agent-containing ferrite containing 2.0% of an azo-based charge control agent with an average particle size of 0.3 μm was uniformly contained. 740 parts of particles are obtained.

<Manufacture and Performance Confirmation of Toner> Saturated polyester resin 67 parts Low molecular weight polypropylene NP-505 (manufactured by Mitsui Petrochemical Co., Ltd.) 3 parts Azo-based charge control agent-containing ferrite particles 30 parts Mixer (Henschel mixer) After dry-mixing with, the mixture was kneaded with a twin-screw kneader whose temperature was set to 130 ° C. The obtained kneaded product is cooled, coarsely pulverized to about 2 mm or less with a hammer mill, finely pulverized with a jet pulverizer having a coarse powder classification function, and classified with an air flow classifier to have an average particle size of 9.3 μm.
To obtain a raw toner of. To 100 parts of the obtained raw toner, 0.3 parts of hydrophobic colloidal silica and 0.5 parts of methyl methacrylate fine particles were added and mixed with a mixer (Henschel mixer), and then aggregates were removed by a vibrating screen to obtain a toner. . This toner was subjected to a continuous copying test of 10,000 sheets using a commercially available copying machine (trade name: NP-6062, manufactured by Canon Inc.). As shown in Table 1, there was no reduction in image density and resolution, no fog occurred, and the transfer efficiency was high.

Comparative Example 2 <Manufacture and Performance Confirmation of Toner> Saturated polyester resin 67 parts Low molecular weight polypropylene NP-505 (manufactured by Mitsui Petrochemical Co., Ltd.) 3 parts Ferrite (FeO.Fe ₂ O ₃ ) particles 28 parts Charge control Agent (azo zinc metal complex) 2 parts The above materials were dry-mixed with a mixer (Henschel mixer), and then kneaded with a twin-screw kneader whose temperature was set to 130 ° C. The obtained kneaded product is cooled and roughly crushed to about 2 mm or less with a hammer mill, then finely crushed with a jet crusher having a coarse powder classifying function, and classified with an airflow classifier to obtain an average particle size of 9.0 μm.
To obtain a raw toner of. To 100 parts of the obtained raw toner, 0.3 parts of hydrophobic colloidal silica and 0.5 parts of methyl methacrylate fine particles were added and mixed with a mixer (Henschel mixer), and then aggregates were removed by a vibrating screen to obtain a toner. . As a result of conducting a continuous copying test of 10,000 sheets of this toner with a commercially available copying machine (trade name: NP-6062, manufactured by Canon Inc.), as shown in Table 1, image density and resolution are low and fogging is often generated. The transfer efficiency was also low.

Table 1 shows the results of evaluation of the copied image at the start of the continuous copying test and the copied image at the end of the continuous copying test for each item for each example and comparative example. The electrophotographic society test chart No. 1-R was used as a copy sample. As the image density, the density of the black solid portion of the copied image was measured with a Macbeth densitometer.
The resolution was evaluated by visually observing the copied image with a magnifying glass and counting the number of individual thin lines. For fog, the density of the non-image portion of the copied image was measured with a Macbeth densitometer. The transfer efficiency is a value obtained by dividing the waste toner amount (increase in the waste toner portion) by the amount of used toner (increase in the developing portion), and multiplying this by 100 to subtract 100.

[0026]

[Table 1]

[0027]

EFFECTS OF THE INVENTION The present invention provides a high quality electrophotographic toner having a high transfer efficiency, which prevents deterioration of the image density and resolution of the toner and generation of fog by the ferrite particles containing an azo type charge control agent and the production method thereof. it can.

[Brief description of drawings]

FIG. 1 is an enlarged view of ferrite particles containing an azo type charge control agent according to the present invention.

[Explanation of symbols]

1 ・ ・ Ferrite particles containing azo type charge control agent, 2 ・ ・
Ferrite, 3 ... Azo compound (charge control agent),

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 61-189561 (JP, A) JP 59-55442 (JP, A) JP 2000-137347 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 9/083 G03G 9/097

Claims (4)

(57) [Claims] 1. A salt containing iron, a solvent comprising water or water and an alcohol, and a hydroxide of an alkali metal are mixed,
A step of oxidizing iron in the salt to form a reaction mixture containing ferrite and a by-product; a step of dissolving and removing the by-product in the reaction mixture in a solvent to extract ferrite; a carboxyl compound and a metal salt. And a step of adding a hydroxide of an alkali metal to ferrite to obtain a charge control agent-containing ferrite, and after diazotizing an aromatic primary amine, mixing a naphthol derivative and coupling, and adding a solvent. An azo-based charge comprising a step of obtaining a monoazo compound-containing solution, and a step of reacting the obtained charge control agent-containing ferrite with a monoazo compound-containing solution to produce an azo-based charge control agent-containing ferrite Manufacturing method of ferrite particles containing a control agent. 2. A process of mixing the extracted ferrite and a positive ion compound to obtain an ion ferrite; adding a carboxyl compound, a metal salt, and a hydroxide of an alkali metal to the ion ferrite to control charge. The method for producing ferrite particles containing an azo-based charge control agent according to claim 1, further comprising the step of obtaining an agent-containing ferrite. 3. The method according to claim 1, which further comprises a step of uniformly mixing the ferrite and the charge control agent and forming particles having an average particle size of 1.0 μm or less in which the ferrite and the charge control agent are integrally attached. The method for producing ferrite particles containing a charge control agent according to claim 1. 4. The method for producing a ferrite particle containing a charge control agent according to claim 1, which comprises a step of purifying a ferrite containing an azo charge control agent.