JP2000258955A - Electrophotographic toner, its production, developer and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a toner having an increased transfer rate and excellent in transferability, transfer retaining property in long-term use and transmittance to OHP. SOLUTION: The toner contains a bonding resin and a colorant and has a sphering degree of 100-130. Spherical colored particles having >=5% indentation rate between protrusions in the projected images of the toner particles occupy >=95% by number. Fine additive particles having 300-500 nm average particle diameter have been stuck to the toner particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner used in electrophotography, a method for producing the same, a developer and an image forming method.

[0002]

2. Description of the Related Art In recent years, it has become necessary to lower the fixing temperature and reduce the amount of untransferred toner remaining after being transferred from a photosensitive member to paper during an electrophotographic process in order to save power and resources. I have. To achieve these, it is necessary to lower the melting point of the toner material and make the toner spherical.

Conventionally, as a general method for producing a toner,
A kneading and pulverizing method is known in which a compounding component of a toner is kneaded and pulverized to obtain a toner having a desired particle size. However, in the kneading and pulverizing method, there is a problem that the toner temperature is easily increased during the process, so that it is difficult to lower the melting of the toner. Further, since the kneaded material is pulverized, the shape of the toner becomes irregular and it is difficult to make the toner spherical. On the other hand, in the suspension polymerization method proposed in Japanese Patent Publication No. 36-10231 or the like, toner spheroidization is easy, but non-spherical particles are mixed because some coalescence occurs in the polymerization step. There is a problem. Further, the polymerizable monomer composition of the resin to be a toner is limited to polymerizable monomers capable of radical polymerization represented by styrene and derivatives thereof, and α-methylene aliphatic monocarboxylic acid esters. Was.

On the other hand, as an electrophotographic toner used in the field of electrophotography, a resin which is instantly melted at the time of fixing and has a smooth image surface, and a polyester which has sufficient flexibility even when the molecular weight is reduced. Often used. In particular, in the case of color toners, polyester resins are often used in terms of color developability and flexibility, and it is necessary to make the toner using polyester into a spherical shape.

Japanese Patent Application Laid-Open Nos. 50-120632, 63-25664, 5-127422, 8-179556 and the like disclose a method for producing a toner capable of spheroidizing polyester. A so-called in-liquid drying method has been proposed in which an oil phase liquid in which a toner component is dissolved is formed into particles in an aqueous phase containing a water-soluble resin, and the solvent is removed to powder the toner component. By making the toner by the submerged drying method, it has become possible to make the polyester spherical necessary for the color toner.

On the other hand, in order to realize the miniaturization of the machine, it is important to eliminate a device for cleaning the toner remaining on the photoreceptor. In particular, in order to realize a miniaturization of a machine using a color toner, it is important to eliminate a device for supplying oil for facilitating peeling of a fixed image from a heating roller at the time of fixing. In order to eliminate the fixing oil, a release agent may be included in the toner. However, in order to eliminate the cleaning device, the transferability of the toner must be improved and the amount of the toner remaining on the photoconductor must be reduced as much as possible. However, the conventional toners are not sufficient to give extremely high transferability.

As a method for improving transferability, Japanese Patent Application Laid-Open
No. 207113 discloses that spherical particles differ in size from spherical particles.
It has been proposed to use two types of inorganic fine particles. Certainly, according to this method, the fluidity is good, cleaning and transferability can be achieved at the same time, and good image quality can be obtained. However, when used in a system that does not use a cleaning device, the transferability is about 90%, which is not sufficient.
The toner remaining without being transferred deteriorates the subsequent image quality.

As a method for improving the transferability, Japanese Patent Application Laid-Open Nos. 9-43905 and 9-197716 disclose that toner particles obtained by a kneading and pulverizing method are heated and spherical in a solvent. Proposed. When this method is used, transferability and blade cleaning performance can be surely improved. Japanese Patent Application Laid-Open No. Hei 10-203939 discloses a system that does not use a cleaning device.
Average particle size of hydrophobic particles on the surface of spherical toner particles 20 to 80
A toner to which an external additive particle of nm is added has been proposed.
By using this method, transferability is good even without a cleaning device, and generation of ghost can be eliminated. However, from the viewpoint of resource saving, when the developer is used for a longer period of time, the above method causes a decrease in transferability, and is insufficient from the viewpoint of a developer having a longer life, which is required in the future.

[0009]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and provides toner transferability, transfer maintenance during long-term use, and O
It is intended to provide a toner having excellent HP permeability.

[0010]

Means for Solving the Problems The inventors of the present invention have made intensive studies on the maintenance of characteristics such as transferability and the like. As a result, unevenness of several μm or less on the toner surface greatly contributes to the maintenance of the characteristics of the spherical toner. I understand that. That is, it has been found that relatively large fine particles, which initially covered the toner surface uniformly, move to the concave portion after long-term use and are unevenly distributed in the concave portion. It has been found that this leads to a decrease in transferability and a decrease in fluidity. As a result of further study, it was found that the toner surface needs to have a specific smoothness in order to stabilize the toner properties such as transferability for a long period of time, and the present invention has been completed.

That is, the present invention contains a binder resin and a colorant, has a degree of sphericity of 100 to 130, and has a dent ratio of 5% between projections in a projected image of toner particles.
The toner for electrophotography is characterized in that the following spherical colored particles are 95% by number or more, and external additive fine particles having an average particle diameter of 30 nm or more and 500 nm or less are attached.

The external additive fine particles having an average particle diameter of 30 nm or more and 500 nm or less may be either inorganic fine particles or organic fine particles. Further, the electrophotographic toner of the present invention preferably further has inorganic fine particles having an average particle diameter of 5 nm or more and less than 30 nm on the surface of the toner particles. When the external additive fine particles having an average particle size of 30 nm or more and 500 nm or less are inorganic fine particles, the inorganic fine particles preferably have a colored particle surface coverage of 20% or more. When the external additive fine particles having an average particle diameter of 30 nm or more and 500 nm or less are organic fine particles, it is preferable that 0.1 to 35 parts by weight of the organic fine particles adhere to 100 parts by weight of the colored particles.

The present invention also provides a method for dissolving and dispersing a binder resin and a colorant in an organic solvent having a solubility of 1 g to 50 g in 100 g of water at 25 ° C. Preparing an oily component, granulating the toner from a state in which the oily component is dispersed in an aqueous medium in which an inorganic dispersion stabilizer is dispersed, and removing the solvent at a temperature lower than the boiling point of the organic solvent. This is a method for producing the electrophotographic toner.

Further, the present invention is a developer comprising the above electrophotographic toner and a carrier.

Further, according to the present invention, a step of forming an electrostatic latent image on an electrostatic latent image carrier, a step of developing toner on the electrostatic latent image, and transferring the developed toner image to a transfer member An image forming method in which the steps are repeatedly performed without cleaning the electrostatic latent image carrier after transfer, wherein the electrophotographic toner is used.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

In the present invention, the degree of spheroidization refers to, for example, FE-SEM (S = 800) manufactured by Hitachi, Ltd.
100 toner images magnified 0 times are randomly sampled, and the image information is introduced into, for example, an image analyzer (Luzex III) manufactured by Nireco via an interface, analyzed, and calculated by the following equation. This is the average of the values (shape-based numerical value MLS2).

MLS2 = (maximum length of toner particles) ² /
(Projected area of toner particles) × π × １ ／ × 100 Toner particles having a sphericity of 100 or more and 130 or less are preferable.
When the degree of spheroidization exceeds 130, the contact area between the photoconductor and the toner increases, so that the transferability decreases. Especially 100 or more 1
It is preferably 20 or less. The shape of the toner produced by the usual kneading and pulverizing method is irregular, and the MLS2 is about 140 to 160.

In the projected image of the toner particles, the dent ratio between the convex portions is 10000 times that of the toner particles.
Using an EM photograph, as shown in FIG. 1, a line was drawn at the top of the protrusion on the circumference and at the top of the protrusion to measure the maximum depth of the recess, and a particle size analyzer TA-II (aperture diameter) manufactured by Coulter Counter Co., Ltd. The average volume particle diameter (diameter) of the toner was measured by using the following formula: dent ratio = maximum depth of concave portion / volume average particle diameter (diameter) of toner × 100 (%). The average particle diameter of the toner is represented by D50 using a value of 50% of the volume average diameter.
If necessary, use GSD to indicate the sharpness of the particle size distribution.
Was used. GSD is the value of the square root of D16 / D84. Furthermore, 100 particles are randomly selected, the number of particles having a dent ratio of 5% or less is counted, and the ratio is represented by number%.
The degree of surface smoothness uniformity was used. The measured dent rate is 5
%, The external additive fine particles having an average particle diameter of 30 nm or more and 500 nm or less gather in the concave portions of the toner surface during long-term use, and transferability is deteriorated. In a toner manufactured by a conventional suspension polymerization method, the dent ratio is hardly reduced to 5% or less.

When the proportion of particles having a dent ratio of 5% or less is less than 95% by number, external additive fine particles having an average particle diameter of 30 nm or more and 500 nm or less gather in concave portions on the toner surface during long-term use, and transferability is deteriorated. It is particularly preferably at least 98% by number.

The surface area ratio of the colored particles means the BET specific surface area S (m ² / g) of the toner, the toner density ρ (g / c
m ³ ), the toner number average particle diameter (diameter) L (μm) was measured with a Coulter counter, and the surface area ratio = S / [4 × π ×
(L / 2 × 10 ⁻⁶ ) ² / ( ^4/3 × π × (L / 2 × 10
^-4 ) ³ × ρ)]. 1 to the surface of the colored particles
If there are minute irregularities of about 0.3 μm, the surface area ratio becomes 1.
If it exceeds 7, the transferability may be deteriorated, possibly because fine particles as external additives enter the minute concave portions. The surface area ratio is preferably 1.7 or less, particularly preferably 1.4 or less.

In the present invention, the average particle size is 30 nm or more and 500 or more.
Fine particles of nm or less are used as external additives. If only the fine particles having an average particle diameter of 5 nm or more and less than 30 nm are used, the external additive fine particles will be buried in the toner surface during long-term use, and the fluidity, transferability and chargeability will decrease. In addition, fine particles having a particle size exceeding 500 nm have low fluidity of the toner, lower the transportability in the developing machine and the mixing property with the carrier, and make it difficult to adhere to the toner surface. The preferred average particle size is 70 nm or more and 500 nm or less. Further, it is more preferable to use two kinds of particles having an average particle diameter of 30 nm or more and 500 nm or less, that is, an average particle diameter of 30 nm or more and less than 70 nm and an average particle diameter of 70 nm or more and 500 nm or less, from the viewpoint of transfer maintenance in long term use. The fine particles having an average particle diameter of 30 nm or more and 500 nm or less are preferably spherical.

Average particle diameter 30 nm attached to colored particle surface
When the particles having a size of 500 nm or less are inorganic particles, specific examples thereof include silicon oxide, titanium oxide, aluminum oxide, barium titanate, strontium titanate,
Metal oxides such as calcium titanate, cerium oxide, zirconium oxide, magnesium oxide, ceramics,
And carbon black. Among these, silicon oxide having a low refractive index is preferable from the viewpoint of the transparency of the OHP fixed image of the toner. Specific examples include colloidal silica particles obtained by a hydrolysis method and spherical silica particles obtained by a deflagration method. Silica particles by the deflagration method are generated by a rapid combustion reaction between silicon and oxygen. Further, these inorganic fine particles are preferably treated with silicone oil from the viewpoint of the transfer maintenance property during long-term use.

Examples of the silicone oil include dimethyl silicone oil, alkyl-modified silicone oil,
α-methyl sulfone-modified silicone oil, chlorophenyl silicone oil, fluorine-modified silicone oil and the like.

As a method of treating silica with silicone oil, known techniques can be used. For example, a method of mixing silica and silicone oil using a mixer, a method of spraying silicone oil in silica using a sprayer, a method of dissolving silicone oil in a solution and then mixing this solution and silica, etc. Is mentioned.

When the external additive fine particles having an average particle diameter of 30 nm or more and 500 nm or less are organic fine particles, those prepared by a general method can be appropriately used. Specific examples include fine particles of cross-linked or non-cross-linked polymethyl methacrylate (PMMA), polystyrene, polystyrene-acryl, polyester, melamine resin, and urea resin.
For example, NJ-1301, N manufactured by Nippon Paint Co., Ltd.
J-207, N-162, FA-1210, FA-13
10, FA-1250, MP-1 manufactured by Soken Chemical Co., Ltd.
000, MP-5000, MP-2701, MP-55
00, MP-1451 and MP-1450. Preferably, a crosslinked polymer compound is good, and spherical fine particles are good.

The electrophotographic toner of the present invention has a particle size of 5 nm or more and 3
Fine particles of less than 0 nm can also be used as external additives. As the fine particles having a size of 5 nm or more and less than 30 nm, inorganic fine particles can be used, and examples thereof include those similar to the above-mentioned inorganic particles. Of these, titanium compounds such as titanium oxide, barium titanate, strontium titanate, and calcium titanate are preferred, and titanium oxide is particularly preferred for suppressing toner fogging in non-image areas during initial use or long-term use.

It is preferable that the surface of these external additives is treated with a coupling material or the like in order to control conductivity, chargeability, and the like. Specific examples of the coupling material include methyltrichlorosilane and dimethyldichlorosilane. , Trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltrisilane Ethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, decyltrimethoxysilane, hexamethyldisilazane, N, N- (bistrimethylsilyl) acetamide, N, N
-Bis (trimethylsilyl) urea, tert-butyldimethylchlorosilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane , Γ
Silane coupling agents such as -glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, and titanium coupling agents. Can be. When the external additive is only inorganic fine particles (including those having an average particle size of 5 nm or more and less than 30 nm), the coverage of the inorganic fine particles on the surface of the colored particles is 20% or more and 100% or less, and the surface area ratio is preferably large. It is 40% or more and 100% or less, which can satisfy the transferability even with toner having irregularities on the surface. 20 coverage
%, The transfer rate becomes extremely poor. The calculation of the coverage was performed by measuring the signal intensities A, B, and C of the inorganic particles of the colored particles only, the inorganic particles only, and the inorganic particles to which the inorganic particles adhered by XPS, and the coverage = (CA). ) /
(BA) × 100.

When using organic fine particles as an external additive,
The weight ratio of the organic fine particles to the colored particles is as follows.
The amount is preferably 0.1 to 35 parts by weight, more preferably 0.1 to 25 parts by weight, and even more preferably 0.5 to 20 parts by weight with respect to 0 parts by weight. If the amount exceeds 35 parts by weight, the image quality is significantly reduced.

As a method of adding the external additive particles to the surface of the colored particles, after the toner is dried, the external additive may be dried and adhered to the toner surface using a mixer such as a V blender or a Hensiel mixer. Then, after the external additive particles are dispersed in an aqueous liquid such as water or water / alcohol, this dispersion may be added to the toner in a slurry state and dried to cause the external additive to adhere to the toner surface. Alternatively, both may be dried while spraying the slurry on the dried external additive (powder).

The absolute value of the charge amount of the toner is 2
It is preferably at least 0 μC / g, particularly preferably at least 30 μC / g.

The average particle size of the toner used in the present invention is 3 μm.
It is preferably not less than m and not more than 10 μm.

As the binder resin, specifically, a known fixing resin can be used. Specifically, alcohol components (ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, butanediol, Dihydric or higher alcohols such as pentanediol, hexanediol, cyclohexanedimethanol, xylylene glycol, dipropylene glycol, polypropylene glycol, bisphenol A, hydrogenated bisphenol A, bisphenol A ethylene oxide, bisphenol A propylene oxide, sorbitol, and glycerin; The alcohol derivative is used alone or in combination, and a carboxylic acid component (maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid,
Divalent or higher carboxylic acids such as adipic acid, trimellitic acid, pyromellitic acid, cyclopentanedicarboxylic acid, succinic anhydride, trimellitic anhydride, maleic anhydride, dodecenyl succinic anhydride, carboxylic acid derivatives and carboxylic anhydrides Acrylates such as polyester, polymethyl acrylate, polyethyl acrylate, polybutyl acrylate, 2-ethylhexyl polyacrylate, lauryl polyacrylate, etc. obtained by condensation polymerization with Polymers, methacrylate polymers such as polymethyl methacrylate, polybutyl methacrylate, polyhexyl methacrylate, poly (2-ethylhexyl methacrylate), polylauryl methacrylate, and copolymers of acrylate and methacrylate , Styrene monomer Copolymers with acrylates or methacrylates, polyvinyl acetates, polyvinyl propionates, polyvinyl butyrate, ethylene polymers such as polyethylene and polypropylene and their copolymers, styrene-butadiene copolymers, styrene- Styrene copolymers such as isoprene copolymer, styrene-maleic acid copolymer, polyvinyl ether, polyvinyl ketone, polyester, polyamide, polyurethane, rubber, epoxy resin, polyvinyl butyral, rosin, modified rosin, terpene resin, phenol Resins and the like can be used alone or as a mixture. Of these, polyester is preferred. 50% of polyester contained in binder resin
When the amount of the polyester is 50% or less, particles having an average particle size of 30 nm or more and 500 nm or less tend to be buried in the toner surface in a long-term use, so that transferability tends to decrease. Further, the intensity of the fixed image and the color development are reduced.

In the present invention, it is preferable to add a wax to the toner from the viewpoint of eliminating the need for oil supply in a fixing device to save space. Specifically, paraffin wax, oxidized paraffin wax, and microcrystalline wax are preferred. Petroleum waxes, mineral waxes such as montan wax, animal and plant waxes such as beeswax and carnauba wax, and synthetic waxes such as polyolefin wax, oxidized polyolefin wax, Fischer-Tropsch wax and the like can be used alone or in combination. The melting point of the wax is preferably 40 ° C to 150 ° C, and 5
0 ° C to 120 ° C is particularly preferred. It is desirable to disperse the wax in advance so that the particle size becomes as small as possible, and it is desirable to disperse the wax to an average of 1 μm or less. As a method of dispersing the wax to reduce the wax particle diameter, a method of wet-grinding the wax in an organic solvent with a media mill, a method of dissolving the wax in the organic solvent, cooling, depositing the wax, and finely dispersing the wax. Alternatively, a method of evaporating the wax in a gas phase to form fine particles can be used. The organic solvent used need not necessarily be the same as the solvent used when dissolving the binder resin. The amount of the solvent is preferably 0.1 to 20 parts by weight of the solvent with respect to 1 part by weight of the wax. The wax can be dissolved by heating, pressing or the like. In the method of evaporating the wax in the gas phase to form fine particles, the gas phase uses helium, argon, or an inert gas of nitrogen, and the wax is heated to 100 ° C to 4 ° C.
After heating to a temperature of 00 ° C. and evaporating under reduced pressure of 0.01 to 10 torr, the evaporated wax fine particles are adhered to the cooled substrate, and then scraped or dispersed in a solvent to form fine particles. At the time of toner granulation, the wax fine particle powder may be added to the toner as it is or may be dispersed in a solvent. In this method, it is also possible to separate a fraction having a narrow molecular weight distribution by adjusting the temperature and the degree of pressure reduction.

As the colorant of the present invention, known organic or inorganic pigments can be used. For example, carbon black such as furnace black, channel black, acetylene black, and thermal black; inorganic pigments such as red, blue, titanium oxide; and azo pigments such as fast yellow, disazo yellow, pyrazolone red, chelate red, brilliant carmine, and para brown. Phthalocyanine pigments such as copper phthalocyanine and metal-free phthalocyanine; condensed polycyclic pigments such as flavantron yellow, dibromoanthrone orange, perylene red, quinacridone red, and dioxazine violet. In the present invention, as the magnetic one-component toner, all or a part of the black coloring material can be replaced with magnetic powder. As the magnetic powder, magnetite, ferrite, a simple metal such as cobalt, iron, nickel, or an alloy thereof can be used. These colorants are added in an amount of about 1 to 50 parts by weight, preferably 2 to 20 parts by weight, based on 100 parts by weight of the resin.

In the present invention, as the pigment dispersing device, a media type dispersing machine such as a sand mill, a ball mill, an attritor, a co-ball mill, a roll mill such as a three-roll mill, a cavitation mill such as a nanomizer, a colloid mill and the like can be used. In order to apply an appropriate shearing force when dispersing the pigment, a part of the binder resin may be added to the pigment dispersion to adjust the viscosity.

In order to keep the dispersion state of the pigment stable, it is preferable to add a pigment dispersant to the toner. Specific examples of the pigment dispersant include EFKA47 and EFKA400.
9, EFKA4010 (modified polyurethane: EFKA
CHEMICALS), Azispar PB711, Azispar PB411, Azispar PA111 (Ajinomoto
Dispalon DA-703-50, Disparon DA-705, Disparon DA-725, Disparon DA-400N (polyester: Kusumoto Kasei Co., Ltd.)
Co., Ltd.) and Solsperse 24000SC (manufactured by Zeneca Corporation).

In order to further stabilize the pigment dispersion by more firmly binding the pigment and the pigment dispersant, it is necessary to add a pigment derivative or the like to the toner or to disperse the pigment that has been subjected to a surface treatment. preferable. Specific examples of the pigment derivative include dimethylaminoethylquinacridone, dihydroquinacridone, a sulfonic acid derivative of anthraquinone, a carboxylic acid derivative of anthraquinone, and Solsperse 5000,
Solsperse 12000, Solsperse 22000 (manufactured by Zeneca), EFKA-745, LP6750 (EFK
A Chemicals). Examples of surface treatment agents for pigments include gum rosin, wood rosin, natural rosins such as tall rosin, abietic acid, levopimaric acid, and abietic acid derivatives such as dextropimaric acid, and calcium, sodium, and potassium salts thereof.
Metal salts such as magnesium salts, rosin-maleic acid resins, rosin-phenol resins, and the like. The amount of the pigment derivative and the pigment surface treatment agent is 0.1 to 100 with respect to the pigment.
% By weight, and particularly preferably in the range of 0.1 to 10% by weight.

In the present invention, a charge control agent may be used. As the charge control agent, those used in conventional developers can be used, but the metal of benzoic acid used in xerographic powder toners can be used. Salt, metal salt of salicylic acid, metal salt of alkyl salicylic acid, metal salt of catechol, bisazo dye containing metal, tetraphenylborate derivative,
A compound selected from the group consisting of a quaternary ammonium salt and an alkylpyridinium salt, a resin-type charge control agent containing a polar group, and a suitable combination of these can be preferably used. The amount of the charge control agent to be added to the toner solid content is generally in the range of 10% by weight or less.

As a method for producing spherical particles using a binder resin containing polyester as a main component, the above-mentioned binder resin,
An oily component obtained by dissolving and dispersing the colorant, the wax, and other materials in an organic solvent, if necessary, is suspended and dispersed in an aqueous medium, and then the solvent is removed. Kneading and kneading the mixture in a non-mixable medium to form a kneaded product in a state where the kneaded product is melted by heating the melted suspension. The method is preferred.

In order to reduce the dent ratio between the projections to 5% or less in the projected image of the toner particles, it is necessary to gradually remove the organic solvent, and gradually evaporate the solvent under the condition that the solvent does not boil. I have to do it. To volatilize the solvent from the suspension containing the solvent, the suspension is dissolved in water to some extent,
It is preferable to volatilize the solvent from an aqueous medium containing water. It is preferable that the solvent dissolves in 1 g to 50 g, preferably 5 g to 20 g in 100 g of water.
Specific examples of the organic solvent include esters such as methyl acetate, ethyl acetate, and butyl acetate, and ketones such as methyl ethyl ketone and cyclohexanone. These may be used alone or as a mixture.
Of these, ethyl acetate is particularly preferred. It is more preferable to use an aqueous medium in which an organic solvent is saturated with water.

In order to reduce the surface area ratio by lowering the acid value of the polyester used for the binder resin, the acid value of the polyester is preferably from 0 mgKOH / g to 10 m
gKOH / g or less, particularly preferably 0 mgKOH / g or more and 5 mgKOH / g or less.

An inorganic dispersion stabilizer can be added to the aqueous medium. Examples of the inorganic dispersion stabilizer include tricalcium phosphate, hydroxyapatite, calcium carbonate, titanium oxide, aluminum hydroxide, magnesium hydroxide, barium sulfate, Examples thereof include silicon oxide, and among them, calcium carbonate is preferable. The amount of the inorganic dispersant is preferably from 1 to 30 parts by weight based on 100 parts by weight of the aqueous medium. Further, the average particle size of the inorganic dispersant particles is preferably 1 μm or less.

As the aqueous medium, water is mainly used, but a water-soluble solvent may be mixed. Further, it is preferable to add a water-soluble polymer in order to stabilize the dispersion of the oil component in the aqueous medium.Specific examples of the water-soluble polymer include cellulose, hydroxypropylmethylcellulose, methylcellulose, carboxymethylcellulose,
Examples include starch, polyvinyl alcohol, and polyacrylic acid.

In the stirring for producing the particles, a rotor-stator stirrer such as a homogenizer and a colloid mill, an impeller stirrer such as a dissolver, an ultrasonic stirrer, and the like are used.

For drying the toner, any of a through-air dryer, a spray dryer, a rotary dryer, a flash dryer, a fluidized-bed dryer, a heat transfer dryer, a freeze dryer, and the like can be used.

[0047]

EXAMPLES (Example 1) C.I. I. Pigment Blue B1
5: 3, 20 parts by weight, 75 parts by weight of ethyl acetate, 4 parts by weight of Dispalon DA-703-50 (polyester amide amine salt, manufactured by Kusumoto Kasei Co., Ltd.) from which the solvent was removed,
1 part by weight of Solsperse 5000 (pigment derivative, manufactured by Zeneca Corporation) was dissolved / dispersed using a sand mill to prepare a pigment dispersion.

Also, 30 parts by weight of paraffin wax (melting point 89 ° C.) and 270 parts by weight of ethyl acetate were used as a releasing agent in DC.
While being cooled to 10 ° C. using a P mill, the mixture was wet-pulverized to prepare a wax dispersion.

A polyester resin comprising bisphenol A propylene oxide adduct, bisphenol A ethylene oxide adduct, and terephthalic acid derivative (Mw = 6)
000, Tg60 ° C, Tm106 ° C, acid value 4mgKOH
/ G) After stirring 136 parts by weight, 34 parts by weight of the pigment dispersion, and 56 parts by weight of ethyl acetate, the wax dispersion 7 was added to the mixture.
5 parts by weight were added, and the resulting mixture was stirred well until it became homogeneous (this solution was designated as solution A). On the other hand, 40 parts by weight of calcium carbonate, 124 parts by weight of a calcium carbonate dispersion dispersed in 60 parts by weight of water, 99 parts by weight of a 2% aqueous solution of cellogen BS-H (Daiichi Kogyo Seiyaku Co., Ltd.), and 157 parts by weight of water Homogenizer (Ultra Turrax: manufactured by IKA)
And stirred for 5 minutes (this solution was designated as solution B).

Further, 345 parts by weight of the liquid B and 250 parts by weight of the liquid A were stirred using a homogenizer (Ultra Turrax: manufactured by IKA) to suspend the mixed liquid. This mixture was stirred with a propeller type stirrer at room temperature and normal pressure for 48 hours to remove the solvent. Next, hydrochloric acid was added to the mixed solution to remove calcium carbonate, and the reaction mixture was washed with water, dried and classified to obtain a toner. The average particle size of the toner was 6 μm.

The surface shape of the obtained toner was observed with a scanning electron microscope (SEM) at an acceleration voltage of 5 kV and a magnification of 10,000.

Next, 1.3 parts by weight of silicon oxide fine particles (RY50: manufactured by Nippon Aerosil Co., Ltd.) treated with 100 parts by weight of silicone toner and treated with silicone oil and having an average particle diameter of 100 nm were manufactured by the deflagration method. 2 parts by weight of silicon oxide fine particles (KMP-105: classified by Shin-Etsu Chemical Co., Ltd.)
And titanium oxide having an average particle diameter of 20 nm (MT150AW:
1.5 parts by weight of fine particles obtained by treating Teica Co., Ltd.) with 20% of decyltrimethoxysilane were mixed in a sample mill,
An electrophotographic toner was prepared.

The coverage of the obtained toner was determined by XPS using the signal intensities A, B, and C of the metal (Ti, Si) of only the colored particles, only the inorganic particles, and the inorganic particles of the colored particles to which the inorganic particles were attached. Measured, coverage = (CA) /
The respective coverages were determined from the formula of (BA) × 100,
The respective covering rates of Ti and Si were summed and determined.

8 parts by weight of the obtained toner and 100 parts by weight of a ferrite carrier whose surface is coated with polymethyl methacrylate are mixed in an environment at a temperature of 20 ° C. and a humidity of 50% to prepare a developer, which is subjected to a blow-off method. To measure the charge amount of the toner. Further, using this developer, A-color 935
(Fuji Xerox Co., Ltd.) Cleaning brush with remodeling machine,
Copying was performed with the cleaning blade removed.
The transfer rate is determined by developing the solid image, stopping the copying machine before transferring and fixing the solid image on paper, measuring the weight A of the toner remaining on the photoconductor and the weight B of the toner transferred on the paper, and B / (A + B) ×
It was determined from the equation of 100 (%). The transferability during long-term use is
After 100,000 copies were made with a modified A-color 935 machine, the transfer rate was determined in the same manner as described above. Also SE
M (scanning electron microscope), acceleration voltage 5 kv, 1000
Observation of the toner surface at 0x revealed that the inorganic fine particles were uniformly attached to the toner surface.

The OHP permeability of the toner was evaluated using A-col.
or935 (manufactured by Fuji Xerox Co., Ltd.)
This was performed by forming a toner image on the P sheet and visually observing the transmittance.

Table 1 shows the evaluation results. (Example 2) 1.3 parts by weight of silicon oxide fine particles (RY50: manufactured by Nippon Aerosil Co., Ltd.) treated with the silicone oil of Example 1 and having an average particle diameter of 40 nm, and an average particle diameter of 100 nm
Silicon oxide fine particles (KMP-10
5: Classified product manufactured by Shin-Etsu Chemical Co., Ltd.) 2 parts by weight of RY50
A toner was obtained in the same manner as in Example 1, except that the amount was changed to 1 part by weight. Table 1 shows the evaluation results. A-color9
The surface of the toner after copying 150,000 sheets with a 35-model remodeling machine was subjected to an accelerating voltage of 5 k using an SEM (scanning electron microscope).
When observed at a magnification of 10000, the inorganic fine particles were uniformly attached to the toner surface. (Example 3) A toner was manufactured in the same manner as in Example 2 except that RY50 in Example 2 was changed to RX50 (silicon oxide fine particles having an average particle diameter of 40 nm treated with hexamethyldisilazane: manufactured by Shin-Etsu Chemical Co., Ltd.). I got Table 1 shows the evaluation results. Comparative Example 1 The external additive inorganic fine particles of Example 1 were replaced with MT150.
A toner was obtained in the same manner as in Example 1, except that AW was changed to only 3.5 parts by weight of fine particles treated with 20% of decyltrimethoxysilane. Table 1 shows the evaluation results. (Comparative Example 2) Instead of stirring the mixture with a propeller-type stirrer at room temperature and normal pressure for 48 hours to remove the solvent in Example 1, the mixture was heated to 80 ° C, which was a temperature exceeding the boiling point of ethyl acetate. A toner was obtained in the same manner as in Example 1 except that the solvent was removed by stirring with a propeller stirrer at normal pressure for 48 hours. Table 1 shows the evaluation results. A-color 935
The surface of the toner after 100,000 copies have been made by the remodeling machine is subjected to an accelerating voltage of 5 kv using an SEM (scanning electron microscope).
Observation at a magnification of 10000 magnification revealed that inorganic fine particles having a large particle size were unevenly attached to the dents on the toner surface. (Example 4) 1.3 parts by weight of silicon oxide fine particles (RY50: manufactured by Nippon Aerosil Co., Ltd.) treated with the silicone oil of Example 1 and having an average particle diameter of 100 nm, and silicon oxide produced by a deflagration method having an average particle diameter of 100 nm Same as Example 1 except that 2 parts by weight of fine particles (KMP-105: classified by Shin-Etsu Chemical Co., Ltd.) was changed to 8.7 parts by weight of a product treated with MT600BW (manufactured by Teica Co., Ltd.) 20% decyltrimethoxysilane. To obtain a toner. Table 1 shows the evaluation results. (Example 5) A polyester resin composed of bisphenol A propylene oxide adduct, bisphenol A ethylene oxide adduct, terephthalic acid derivative and trimellitic acid (Mw = 100)
00, Tg64 ° C, Tm111 ° C, acid value 15mgKOH
/ G) to obtain a toner in the same manner as in Example 1. Many holes of about 0.3 μm were observed on the toner surface. Table 1 shows the evaluation results. (Example 6) A polyester resin composed of bisphenol A propylene oxide adduct, bisphenol A ethylene oxide adduct, terephthalic acid derivative and benzoic acid (Mw = 20,000,
Tg66 ° C, TTm106 ° C, acid value 4mgKOH / g) 4
A toner was obtained in the same manner as in Example 1, except that 0 parts by weight and 95 parts by weight of a styrene-acrylic acid-lauryl methacrylate copolymer (Mw 5000, Tg 63 ° C.) were used. Table 1 shows the evaluation results.

[0057]

[Table 1]

From Table 1, it can be seen that the electrophotographic toner of this embodiment has good initial and long term transfer rate and image quality. (Example 7) C.I. 1. Pigment Blue B15: 3,1
8 parts by weight, 80 parts by weight of ethyl acetate, 4 parts by weight of disparone DA-703-50 (polyester amide amine salt, manufactured by Kusumoto Kasei Co., Ltd.) from which the solvent has been removed, Solsperse 5000 (pigment derivative, manufactured by Zeneca Corporation) 1) Part by weight was dissolved / dispersed using a sand mill to prepare a pigment dispersion.

Also, 28 parts by weight of paraffin wax (melting point 89 ° C.) and 280 parts by weight of ethyl acetate were used as a releasing agent in DC.
While being cooled to 10 ° C. using a P mill, the mixture was wet-pulverized to prepare a wax dispersion.

Polyester resin comprising bisphenol A propylene oxide adduct, bisphenol A ethylene oxide adduct, and terephthalic acid derivative (Mw = 6)
200, Tg 63 ° C, Tm 108 ° C, acid value 4mg KOH
/ G) After stirring 135 parts by weight, 33 parts by weight of the pigment dispersion, and 57 parts by weight of ethyl acetate, 74 parts by weight of the wax dispersion were added to the mixture, and the resulting mixture was stirred well until it became uniform (this liquid was mixed). A liquid).

On the other hand, calcium carbonate 34 parts by weight, water 58
125 parts by weight of a calcium carbonate dispersion dispersed in parts by weight,
98 parts by weight of a 2% aqueous solution of cellogen BS-H (Daiichi Kogyo Seiyaku Co., Ltd.) and 155 parts by weight of water were stirred for 5 minutes using a homogenizer (Ultra-Clax: manufactured by IKA). did).

Further, 340 parts by weight of the solution B and 245 parts by weight of the solution A were stirred using a homogenizer (Ultra Turrax: manufactured by IKA) to suspend the mixture. The mixture was stirred with a propeller type stirrer at room temperature and normal pressure for 48 hours to remove the solvent. Next, hydrochloric acid was added to the mixed solution to remove calcium carbonate, and the reaction mixture was washed with water, dried and classified to obtain a toner. The average particle size of the toner was 6.3 μm.

The surface shape of the obtained toner was observed with a scanning electron microscope (SEM) at an acceleration voltage of 5 kV and a magnification of 10,000.

Next, styrene-acrylic crosslinked fine particles (NJ-1) having a particle diameter of about 350 nm were added to 100 parts by weight of the toner.
301: 2 parts by weight of Nippon Paint Co., Ltd., silicon oxide fine particles (R
Y50: 1.3 parts by weight, titanium oxide having an average particle diameter of 20 nm (MT150AW: Teica Corporation)
Was treated with 20% decyltrimethoxysilane, and 1.5 parts by weight of fine particles were mixed with a sample mill to prepare a toner.

A developer was prepared by mixing 8 parts by weight of the obtained toner and 100 parts by weight of a ferrite carrier whose surface was coated with polymethyl methacrylate in an environment at a temperature of 20 ° C. and a humidity of 50%. Further, using the obtained developer, Ac
Color 935 (manufactured by Fuji Xerox Co., Ltd.) was used for copying with the cleaning brush and cleaning blade removed. The transfer rate was evaluated in the same manner as in Example 1. The transferability during long-term use is 1 with a modified A-color 935.
After 50,000 copies were made, evaluation was made in the same manner as in the transfer rate. When the surface of the toner was observed using an SEM (scanning electron microscope) at an acceleration voltage of 5 kv and a magnification of 10,000, the organic fine particles were uniformly attached to the toner surface.

The OHP permeability of the toner was evaluated in the same manner as in Example 1.

Table 2 shows the evaluation results. (Embodiment 8) The organic fine particles of the embodiment 7 have a particle diameter of about 180.
A toner was obtained in the same manner as in Example 7, except that styrene-acrylic fine particles (N-162: manufactured by Nippon Paint Co., Ltd.) were changed to 2 parts by weight. Table 2 shows the evaluation results. A-
When the surface of the toner after performing 150,000 copies with a co1or 935 modified machine was observed at an acceleration voltage of 5 kv and a magnification of 10000 using an SEM (scanning electron microscope), organic fine particles were uniformly attached to the toner surface. Example 9 Example 7 was repeated except that the organic fine particles of Example 7 were changed to 2 parts by weight of a 400-nm cross-linked polymethyl methacrylate polymer prepared by a known soap-free emulsion polymerization method.
A toner was obtained in the same manner as described above. Table 2 shows the evaluation results. (Example 10) Bisphenol A propylene oxide adduct, bisphenol A ethylene oxide adduct, terephthalic acid derivative,
Polyester resin composed of trimellitic acid (Mw = 11
000, Tg65 ° C, Tm113 ° C, acid value 14mgKO
H / g), to obtain a toner in the same manner as in Example 7. Many holes of about 0.45 μm were observed on the toner surface. Table 2 shows the evaluation results. Example 11 The polyester resin of Example 7 was obtained by adding bisphenol A propylene oxide adduct, bisphenol A ethylene oxide adduct, terephthalic acid derivative,
Polyester resin composed of benzoic acid (Mw = 2100
0, Tg65 ° C, Tm104 ° C, acid value 4mgKOH /
g) A toner was obtained in the same manner as in Example 7, except that 95 parts by weight and 40 parts by weight of a styrene-acrylic acid-lauryl methacrylate copolymer (Mw5000, Tg62) were used. Table 2 shows the evaluation results. (Comparative Example 3) CPR100 (styrene-acrylic non-crosslinked resin: manufactured by Mitsui Toatsu Co., Ltd.) was pulverized with the organic fine particles of Example 7,
Classified into amorphous resin particles of about 1000 nm 5
A toner was obtained in the same manner as in Example 7, except that the amount was changed to parts by weight. Table 2 shows the evaluation results. (Comparative Example 4) A toner was obtained in the same manner as in Example 7, except that the organic fine particles of Example 7 were changed to 2 parts by weight of a 600-nm crosslinked polystyrene-acrylic polymer produced by a known soap-free emulsion polymerization method. . Table 2 shows the evaluation results. (Comparative Example 5) Instead of stirring the mixture with a propeller-type stirrer at room temperature and normal pressure for 48 hours to remove the solvent in Example 7, the mixture was heated to 90 ° C, a temperature exceeding the boiling point of ethyl acetate. A toner was obtained in the same manner as in Example 7, except that the solvent was removed with a propeller-type stirrer at normal pressure for 48 hours. Table 2 shows the evaluation results. Further, the surface of the toner after performing 150,000 copies with an A-color 935 modified machine is referred to as S
Using an EM (scanning electron microscope), acceleration voltage 5 kV, 100
Observation at a magnification of 00 revealed that organic fine particles having a large particle diameter were unevenly attached to the dents on the toner surface.

[0068]

[Table 2]

From Table 2, it can be seen that the toner of the present example has a good transfer rate at the initial stage and after the running.

[0070]

According to the present invention, it is possible to obtain a toner for developing an electrostatic latent image excellent in transferability, transferability in long-term use, and OHP transparency.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a dent ratio.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Akira Matsumoto 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Hirotaka Matsuoka 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Hiroshi Sugisaki 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Yusaku Shibuya 1600 Takematsu Minami Ashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. 1600 Fuji Xerox Co., Ltd. (72) Inventor Seiichi Takagi 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture F Xerox Co., Ltd. F-term (reference) 2H005 AA15 AA21 AB03 CA21 EA05 FA02

Claims (4)

[Claims] Claims: 1. A binder resin and a colorant, having a sphericity of 1
The number of spherical colored particles having a dent ratio of 5% or less in the projected image of the toner particles is 95% by number or more, and the average particle diameter is 30 nm or more and 500 nm or less. An electrophotographic toner to which additive fine particles are attached. 2. An oily component is prepared by dissolving and dispersing a binder resin and a colorant in an organic solvent having a solubility of 1 g to 50 g in 100 g of water at 25 ° C. And granulating the toner from a state in which the oily component is dispersed in an aqueous medium in which an inorganic dispersion stabilizer is dispersed, and removing the solvent at a temperature lower than the boiling point of the organic solvent. Manufacturing method 3. A developer comprising the electrophotographic toner of claim 1 and a carrier. 4. A step of forming an electrostatic latent image on an electrostatic latent image carrier, a step of developing toner on the electrostatic latent image, and a step of transferring the developed toner image onto a transfer body, An image forming method, wherein the toner for electrophotography according to claim 1 is used in an image forming method that is repeatedly performed without cleaning the electrostatic latent image carrier after transfer.