JP2001117275A - Electrophotographic color toner, electrophotographic developer and method of forming image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic color toner, an electrophotographic developer and a method of forming an image by which a wide fixing temperature region and excellent low temperature fixing property are obtained without decreasing the toner characteristics, the permeation of the toner into paper is suppressed and a color image with highly developed colors and high picture quality can be stably formed. SOLUTION: The electrophotographic color toner contains toner particles consisting of a binder resin, a coloring agent, and pale color or colorless fine particles. In the electrophotographic color toner and electrophotographic developer, the fine particle have an acyl group expressed by general formula (I) on its surface, and the dynamic complex elastic modulus G* (under conditions of 100% distortion rate and 10 rad/see frequency) of the toner is 3000 to 50000 Pa measured at the temperature where the dynamic complex elastic modulus G* (under conditions of 100% distortion rate and 10 rad/see frequency) of the binder resin is 1000 Pa. In the formula, R is a monovalent substituent selected from among aliphatic hydrocarbon groups, alicyclic hydrocarbon groups and aromatic hydrocarbon groups consisting of carbon atoms and hydrogen atoms.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic color toner, an electrophotographic developer, and an image forming method used in an image forming apparatus such as a copying machine, a printer, a facsimile, etc. using an electrophotographic method. The present invention relates to a color toner for electrophotography excellent in fixability, a developer for electrophotography, and an image forming method using the developer for electrophotography.

[0002]

2. Description of the Related Art Many electrophotographic systems used in copying machines have been known, including a method described in Japanese Patent Publication No. 42-23910. In the electrophotographic method, usually, a latent image is formed electrically on a photoreceptor using a photoconductive substance by various means, and the latent image is developed using toner, and the toner formed on the photoreceptor is formed. After the image is transferred to or from a transfer medium used for image recording, such as paper, with or without an intermediate transfer member, the transferred image is fixed by heating, pressing or heating and pressing, or solvent vapor or the like. An image is formed through a plurality of steps such as. After the image formation, the toner remaining on the photoreceptor is cleaned by various methods as necessary, and the image formation can be performed one after another by repeating a plurality of steps similar to the above.

[0003] Such an electrophotographic system is widely used not only for copying machines but also for various image forming apparatuses such as printers and facsimile machines due to the development of devices such as computers in the information society in recent years and the enhancement of communication networks. At the same time, colorization is progressing rapidly. Under these circumstances, high-quality document creation and design work can be performed at high speed and easily using information equipment such as a word processor and a computer, and a color copying machine, a printer, a facsimile machine using an electrophotography system. (Hereinafter, these are collectively referred to as “electrophotographic devices”). As a result, in an electrophotographic apparatus for forming a color image, it is required that the output image has high color development and high image quality.

In order to realize high-color and high-quality image output (output), the toner image transferred to the transfer-receiving member is sufficiently melted from the viewpoint of translucency and glossiness of the image. Its surface must be smooth. Therefore, in the conventional color electrophotographic apparatus, as a fixing step, a contact-type heat and pressure fixing method excellent in thermal efficiency, reliability and safety is adopted, and a toner having a low molecular weight and a solid Resins that rapidly soften from a glassy state by heating and decrease in melt viscosity have been used as binder polymers.

However, in recent years, interest in environmental issues has increased, and due to the trend toward resource saving and energy saving, there has been a tendency to reduce the heat energy used in the fixing process in order to reduce the power consumption required for the electrophotographic apparatus. Therefore, it is required to lower the set temperature of the fixing device and reduce the power required for heating. Generally, as a contact-type heating and pressing fixing method, a fixing method using a heat roller is widely used. In this fixing method, when the surface of the heat roller contacts the surface of the toner,
There is a case where a so-called offset phenomenon occurs in which the toner attached to the roller surface is transferred to a transferred body which is sent later.

In this case, the fixing lower limit temperature is between the low temperature offset and the high temperature offset. Therefore, the temperature range in which the actual fixing can be performed is between the fixing lower limit temperature and the high temperature offset. Therefore, by lowering the fixing lower limit temperature as much as possible and raising the temperature at which the high-temperature offset occurs as much as possible, the fixing temperature range can be expanded and low-temperature fixing properties can be imparted. For this reason, as a means for fixing at a lower limit temperature lower than before without sacrificing the output of high color development and high image quality, the glass transition temperature (hereinafter, “Tg”) of the binder resin used for the toner is used. Lowering the softening temperature of the toner may be considered.
On the other hand, the toner is always required to have fixability and offset resistance. Therefore, in order to improve these properties, the degree of polymerization of the polymer used as the binder resin is increased, or a cross-linking structure or a gel component is introduced into the polymer to increase the cohesive force at the time of melting the toner, and the roll surface is increased. Means such as preventing fusion of the toner to the toner are employed. Also,
For the purpose of improving the releasability from the roll surface, addition of a polymer having a low molecular weight component has been attempted.

However, when the low-temperature fixing property is imparted to the toner by lowering the Tg of the binder resin, the toner may be left in a toner cartridge or a developing machine for a long period of time.
Blocking due to thermal agglomeration is likely to occur, and there is a concern about storage stability, and if the transferred object after fixing is left in contact with other objects under high temperature conditions such as in a car under hot weather, A phenomenon called document offset in which the binder resin is softened and the image is fused is likely to occur.

As described above, when the method of increasing the degree of polymerization of the polymer used for the binder resin is effective in offset resistance, it not only raises the minimum fixing temperature but also increases the kneading and pulverizing method. It is also expected that the pulverizability deteriorates in the toner production process due to the above. Further, when used as a color toner, there is a possibility that the surface glossiness, which is an essential property for outputting a high-colored and high-quality image, may be impaired. Although the offset resistance can be improved by the method of adding the low molecular weight component, there is a concern about storage stability and a document offset is likely to occur as in the case where the Tg of the binder resin is lowered.

On the other hand, with the spread of color electrophotographic devices,
The color toner used in the apparatus has a problem that arises from a viewpoint different from resource saving and energy saving. That is, since the color toner softens rapidly as described above, the range of the change of the melt viscosity with respect to the temperature change at the time of fixing is large, and the melt viscosity at the time of fixing is low. For this reason, when using paper that is the mainstream among the transfer media used for image recording, the toner that should normally be placed on the surface of the paper penetrates between the fibers in the paper (hereinafter referred to as “penetration phenomenon”). There is a disadvantage that the image is deteriorated. Therefore, in order to output the formed image with high color and high image quality, it is possible to reduce the permeation phenomenon, and to use paper for a specific color, such as paper coated with a resin or the like, or paper with a dense fiber interval. Had to be used.

However, in the production of documents in business, there are a wide variety of documents including not only black and white documents but also color documents and black and white / color mixed documents. In particular, in a business setting where it is essential to improve productivity, it is inefficient to perform monochrome / color and printout on separate models, and the cost is high. It is strongly desired to be able to output both color images, and the paper used for this is also the paper conventionally used in black-and-white electrophotographic apparatuses (hereinafter referred to as "plain paper"). Has been required to be used in color applications. However, since plain paper has a smaller heat capacity than color-only paper, the amount of heat applied to the toner at the time of fixing tends to increase, and the melting of the toner proceeds extremely more than fixing using color-only paper. , Falls into a region of lower viscosity. As a result, plain paper, which has a lower fiber density than color paper,
A new problem arises in that the toner penetration phenomenon is conspicuous, and the formed image is deteriorated as compared with the case where color dedicated paper is used.

On plain paper, the thickness of the fibers is about several tens of μm, and the voids are similar to or larger than the fibers, so that they are visually observed as white spots or image irregularities such as lint-like patterns. You. In particular, in the case of a solid image having the same density and occupying a large area, the image becomes very uncomfortable. Such a phenomenon of image deterioration occurs in image forming apparatuses other than the electrophotographic apparatus, for example, in a printing / ink-jet method or the like, a special paper having an image receiving layer such as a coated paper, or a chemical curing reaction. Is used to prevent bleeding of the printing ink, and the solution is very difficult. However, it is important to utilize the excellent convenience of the electrophotographic apparatus for black-and-white output and to provide a high image quality technology that does not use any paper even in color output.

Further, in response to recent demands for higher image quality, there is a movement to reduce the thickness of a fixed image transferred onto a transfer target. In a conventional electrophotographic apparatus, the thickness of an obtained image (thickness of a toner image after fixing) is 5 to 5 per color.
Since the thickness is as large as 7 μm and reaches as large as 20 μm in a full-color image, the difference in thickness between a portion having a high image density and a portion having a low image density gives a viewer a sense of incongruity. On the other hand, in the case of a printed high-quality image, the image thickness is several μm even in full color, and the user does not feel uncomfortable as described above.
Therefore, also in the electrophotographic apparatus, it is expected that the resolution is increased by reducing the particle diameter of the toner as much as possible, and the image quality is thin and the image quality is as high as that of a printed image. However, in contrast to printing on the premise that coated paper is used, in the case of an electrophotographic image using paper having a lower surface smoothness than coated paper, if the image thickness is too thin, image deterioration due to penetration as described above will occur. Is more likely to occur. Moreover, if the use of plain paper is a prerequisite for a color output electrophotographic apparatus, the conditions for achieving high image quality are becoming more severe, and from this point, prevention of the phenomenon of penetration into paper is strongly desired. .

Hitherto, no method has been proposed for directly preventing the phenomenon of toner permeation into paper, and there have been proposed techniques having some similar effects. For example, Japanese Unexamined Patent Publication
In JP-A-332247, fine particles are contained in the toner to reduce the rate of change of the melt viscosity with respect to temperature.
A technique for achieving both low-temperature fixability and offset resistance has been proposed. Specifically, as a binder resin, a number average molecular weight of 10
A polyester resin having an acid value of 10 to 5000 mgKOH / g and an average particle diameter of 0.05 to 2.0
A technology including a μm crosslinked resin particle as a domain is disclosed. In this method, the melt viscosity curve is certainly improved, but when particles having a large average particle diameter are contained,
Glossiness cannot be obtained in the formed image, and the coloring property is also reduced. Also,
No mention is made of the dispersibility of the molecules, and if the dispersibility is poor, the penetration phenomenon cannot be prevented. Further, since a solvent is used for mixing the particles and the binder resin, the particles made of the resin dissolve or swell, and as a result, the particles also aggregate. Further, in order to remove the solvent after mixing, drying at a high temperature is required. As a result, aggregation of particles due to heating and thermal deterioration of the resin may occur. Once the particles are agglomerated, it is difficult to prevent the toner from penetrating, and there is also a problem that other toner characteristics such as chargeability are deteriorated due to thermal deterioration of the resin.

JP-A-8-220800 discloses a toner in which inorganic particles are contained in a binder resin, the viscoelastic characteristics of each color are the same as that of a black toner, and the offset resistance is improved. . Although this method can improve the viscoelastic properties of the toner, it has little effect on the offset resistance of a high-speed electrophotographic apparatus that requires high speed, high color development and high image quality. Not obtained. Further, when the amount of the inorganic particles added is 1 to 10% by weight, it cannot be said that the penetration phenomenon in a viscosity region higher than the viscosity at which the high-temperature offset occurs is insufficient.

As described above, no color toner for electrophotography has been provided yet, which can achieve both the expansion of the fixing temperature range and the low-temperature fixing property, and can sufficiently prevent the toner from penetrating into plain paper. Therefore, at present, there has not been provided an electrophotographic developer which is excellent in fixing property at a low temperature, suppresses penetration of toner into plain paper, and can stably form a high-quality color image.

[0016]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and achieve the following objects. In other words, the present invention provides a color image with high color development and high image quality, with a wide fixing temperature range, excellent fixability at low temperatures, and suppression of toner penetration on paper other than specialty paper, without causing deterioration in toner characteristics. It is an object of the present invention to provide an electrophotographic color toner capable of stably forming a color toner. Further, the present invention has excellent fixability at a low temperature, prevents deterioration of the image quality of a toner image due to toner penetration even on paper other than dedicated paper, and can stably form a high-color, high-quality color image. An object of the present invention is to provide an electrophotographic developer. Still another object of the present invention is to provide an image forming method capable of stably forming a high-color, high-quality color image.

[0017]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on the fixing of color toners, paying attention not only to the melt viscoelastic properties of the toner but also to the surface properties such as the unevenness of the transfer object. The following findings were obtained. That is, it is found that when fine particles having an organic functional group on the surface thereof are used as fine particles constituting the toner particles, the viscosity characteristics of the toner at the time of melting can be controlled without affecting various characteristics of the toner. It is. The means for solving the above problems are as follows. That is,

<1> At least a binder resin, a colorant and a light
Including toner particles composed of colored or colorless fine particles.
In the color toner for photo photography, the fine particles are
Having an acyl group represented by the following general formula (I) on the surface, and
Dynamic complex elastic modulus G of the binder resin^*(Distortion rate = 100
%, Frequency = 10 rad / sec) indicates 1000 Pa
Complex elastic modulus G of the toner, measured at the temperature
^*(Distortion rate = 100%, frequency = 10 rad / sec)
Is between 3,000 and 50,000 Pa
It is a color toner for electrophotography.

[0019]

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[In the formula, R represents a monovalent substituent selected from an aliphatic hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group, consisting of a carbon atom and a hydrogen atom. ]

The color toners for electrophotography shown in the following <2> to <4> are also preferable embodiments. <2> On the surface of the fine particles, there is provided an acyl group directly covalently bonded to the fine particles, or a compound containing at least one acyl group in a molecule, which is covalently bonded to the fine particles at a site other than the acyl group. <2> The color toner for electrophotography described in (1). <3> The average primary particle diameter of the fine particles in the toner is 1 to 5
The electrophotographic color toner according to <1> or <2>, which has a thickness of 00 nm.

<4> The toner according to any one of <1> to <3>, wherein the number of toner particles containing fine particles having a particle diameter of 1.0 μm or more is 50% or less of the total number of toner particles in the electrophotographic color toner. 4. The color toner for electrophotography described in 1. above. <5> The melting point or glass transition temperature of the fine particles is 13
The color toner for electrophotography according to any one of <1> to <4>, wherein the temperature is 0 ° C. or higher.

<6> At least the above <1> to <5>
An electrophotographic developer comprising the electrophotographic color toner according to any one of the above.

<7> A step of forming a latent image on the latent image holding member, a step of developing the latent image with an electrophotographic developer to form a toner image, and a step of transferring the toner image onto a transfer-receiving member And a step of fixing the toner image transferred onto the transfer target body, wherein the electrophotographic developer is the electrophotographic developer according to <6>, An image forming method is characterized in that a heating contact type fixing device is used in the step of fixing the toner image.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION In the color toner for electrophotography of the present invention, fine particles having an acyl group on the surface thereof are used as fine particles constituting the toner particles, and the dynamic complex elasticity of a binder resin used together with the fine particles is used. The rate G ^* (distortion rate = 100%, frequency = 10 rad / sec) is 1000
Dynamic complex elastic modulus G ^{* of} toner particles measured at a temperature indicating Pa (strain rate = 100%, frequency = 10 rad /
sec) is 3000 to 50,000 Pa. The electrophotographic developer of the present invention comprises at least the electrophotographic color toner of the present invention. In the image forming method of the present invention, at least a step of forming a latent image, a step of forming a toner image, a step of transferring the toner image onto a transfer medium, and a step of fixing the transferred toner image In the step of forming the toner image, the electrophotographic developer of the present invention is used, and in the step of fixing the transferred toner image, a heat contact type fixing device is used. Hereinafter, the electrophotographic color toner of the present invention will be described in detail, and the details of the electrophotographic developer and the image recording method will be clarified through the description.

<Electrophotographic Color Toner> The electrophotographic color toner of the present invention contains at least a binder resin, a colorant, and toner particles composed of light-colored or colorless fine particles. It may have a component.

(Fine Particles) In the present invention, fine particles having an acyl group represented by the following general formula (I) as a terminal group on the surface of the fine particles are used as the light-colored or colorless fine particles.

[0028]

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In the above formula, R represents a monovalent substituent selected from an aliphatic hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group, consisting of a carbon atom and a hydrogen atom. Examples of the aliphatic hydrocarbon group include an alkyl group represented by the following (1), and examples of the alicyclic hydrocarbon group include the following (2)
As the aromatic hydrocarbon group, the cyclohexyl group shown in the following is a phenyl group shown in the following (3), an alkylphenyl group shown in the following (4), a benzyl group shown in the following (5), and the like. From the viewpoint of raw material availability and ease of synthesis, an alkyl group or phenyl group having 20 or less carbon atoms is more preferable. In the following (1) and (4), n is
Represents an integer of 1 or more.

[0030]

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The acyl group represented by the general formula (I) is
At the surface of the fine particles constituting the toner particles, the fine particles are directly covalently bonded to the fine particles, or the compound containing at least one acyl group in the molecule is covalently bonded to the fine particles at a site other than the acyl group. , Through the compound. Usually, the acyl group is represented by a ketone represented by the following (6), a carboxylic acid represented by the following (7), an acid chloride represented by the following (8), or a following acid chloride (9) in the organic compound. Exists in the form of an ester bond or an amide bond represented by the following formula (10), and overlaps an electron orbit with an adjacent element, and bonds to another molecule in a covalent bond state in which electrons are shared and becomes stable. I do.

[0032]

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A covalent bond is formed when a compound and another compound form a bond by a chemical reaction, and is called a chemical bond that forms a bond between elements in the compound along with an ionic bond and a metal bond. It is common in organic compounds. In general, when bonded by a covalent bond, very large energy is required to dissociate the element. Therefore, when an organic functional group such as an acyl group is present on the surface of the fine particles, the acyl group and the fine particles can be firmly bonded to each other by a covalent bond. It is possible to avoid a concern that the predetermined effect cannot be obtained due to detachment.

Therefore, in order for the acyl group represented by the general formula (I) to be present on the surface of the fine particles, a carboxylic acid or an acid chloride is directly bonded to a reactive group present on the surface of the fine particles, or For example, a method of introducing a compound having a ketone, an ester bond, or an amide bond in the molecule to the surface of the fine particles may be used. When the compound is introduced into the surface of the fine particles in the form of a compound, the compound is preferably a compound having both an acyl group and another reactive group which reacts with the surface of the fine particles in the molecule, as described later.

As described above, by using the fine particles having the acyl group represented by the general formula (I) on the surface thereof as the fine particles constituting the toner particles, the acyl group becomes Direct contact with the polymer molecules constituting the binder resin in the toner particles causes an interaction between the surface of the fine particles and the polymer molecules to control the viscoelastic properties of the electrophotographic color toner.

Hereinafter, the fine particles having the acyl group represented by the general formula (I) (hereinafter sometimes simply referred to as “acyl group”) on the surface thereof will be described. The method for producing the fine particles is not particularly limited and can be appropriately selected from conventionally known production methods. For example, the fine particles can be produced by the following method.

That is, (1) a method of treating the surface of inorganic fine particles with a reactive compound to introduce an acyl group;
(2) a method of directly synthesizing fine particles using an inorganic substrate as a raw material from an organic hetero element compound containing an acyl group in advance, and (3) treating the surface of the organic fine particles with a reactive compound to obtain an acyl group. (4) polymerizing an organic compound containing an acyl group in advance as a raw material,
A method of directly synthesizing fine particles using an organic substance as a substrate.

The details are as follows. As the method (1), for example, a compound having a reactive group such as a coupling agent having an acyl group is directly reacted with fine particles of a metal oxide or a non-oxide, or a metal oxide or a non-oxide. After introducing a polymerization initiating group into the fine particles, a method in which a monomer having an acyl group introduced therein is graft-polymerized.

As the metal oxide and non-oxide fine particles, colorless or light-colored inorganic fine particles having an average particle diameter of 1 to 300 nm are preferable. Specifically, silica, alumina, titanium oxide, zinc oxide, cerium oxide, magnesium oxide, zirconium oxide, antimony trioxide, red iron oxide, silica sand, wollastonite, diatomaceous earth, clay, mica, barium sulfate, barium titanate, Magnesium titanate,
Examples thereof include calcium titanate, cerium chloride, silicon carbide, and silicon nitride. Among them, silica-based fine particles and titania-based fine particles are preferable.

The method for producing the inorganic fine particles is not particularly limited, and can be produced by a conventionally known method. For example, in the case of an oxide, a method of heating and hydrolyzing a chloride (silicon tetrachloride, titanium tetrachloride, etc.) in a gas phase, a method of synthesizing by a wet method such as a sol-gel method, a method of high-temperature melting, and the like. Is mentioned.

When a compound having a reactive group having an acyl group introduced is directly reacted with the surface of the inorganic fine particles, examples of the compound include a coupling agent such as a silane coupling agent and a titanate coupling agent, and an isocyanate. And acid chlorides. Here, as a method of directly reacting, for example, alcohol, hexane, toluene, ethyl acetate, acetone, methyl ethyl ketone, tetrahydrofuran (hereinafter abbreviated as “THF”),
A solution of the compound mixed and diluted with a solvent such as water is thoroughly mixed by forcibly dropping or spraying the fine particles with a blender, followed by washing / filtration as necessary, followed by heating and drying, and further aggregation. A method of crushing and treating in a blender or mortar, etc., a method of immersing the fine particles in a solution of the compound, and then precipitating, drying by heating and crushing the fine particles, dispersing the fine particles in a solvent to form a slurry And a method in which the mixture is precipitated with heat, dried by heating, disintegrated and treated, or a method in which the compound is directly mixed and sprayed on the fine particles and treated.

In the case where graft polymerization is carried out after introducing a polymerization initiating group on the surface of the inorganic fine particles, the following procedure is carried out. That is, as the polymerization initiating group, a radical polymerization initiating group such as a vinyl group, an azo group and a peroxide group; a cationic polymerization initiating group such as a sulfonium base and a chloromethyl group; an anionic polymerization initiating such as a lithium silanolate group and an amino group And the like, and these polymerization initiating groups are
The compound is introduced using a compound having a reactive group such as a coupling agent or an isocyanate or an acid chloride. After the introduction, as a method of performing a graft polymerization reaction, as in the case of the direct reaction described above, for example, a monomer solution which is a raw material for graft polymerization mixed and diluted with a solvent is forcibly dropped or sprayed onto fine particles by a blender. And then, after heating, washing, and filtering as necessary, heating and drying, and further crushing and treating the aggregates in a blender or a mortar,
A method in which the fine particles are immersed in a monomer solution for treatment, a method in which the fine particles are dispersed in a solvent to form a slurry, and the slurry is mixed with the monomer solution for treatment are exemplified.

Examples of the monomer as a raw material include a vinyl compound having an acyl group, an epoxide, a cyclic acid anhydride, a cyclic amide, a cyclic ester, and the like. These monomers having an acyl group alone, or a monomer having an acyl group and a monomer having an acyl group are used. An acyl group is introduced on the surface of the fine particles by a copolymer with a monomer that is not used.

In the above method (2), for example, a trifunctional metal alkoxide such as an acyl group-containing trimethoxysilane is used as an organic hetero element compound containing an acyl group in advance, and this is subjected to a gas phase discharge reaction or a sol. -A method of synthesizing by a wet hydrolysis reaction by a gel method, and the like.

The organic hetero element compound containing an acyl group is not particularly limited, but is preferably a trifunctional metal alkoxide from the viewpoint of easiness of the reaction. The group titanium trimethoxide is preferred.

As the method (3), for example, similarly to the method (1), an organic fine particle having a reactive surface such as a hydroxyl group, a carboxyl group, an amino group, or an isocyanate group introduced into the particle surface is used. A method in which an acyl-containing compound capable of reacting with a group is directly reacted, or a method in which an acyl group is introduced by graft polymerization into organic fine particles into which a polymerization initiating group has been introduced.

The organic fine particles are not particularly limited, and include, for example, vinyl, styrene, (meth) acrylic, ester, amide, melamine, ether, and the like.
A single resin such as an epoxy resin, or fine particles made of these copolymer resins can be mentioned. Among them, vinyl-based, styrene-based,
Fine particles composed of an addition polymerization resin represented by (meth) acrylic resin (addition polymerization resin fine particles) and fine particles composed of a polycondensation resin represented by an ester resin (polycondensation resin fine particles) are preferable.

The method for producing the organic fine particles is not particularly limited, and can be appropriately selected from conventionally known methods. Examples of the method for producing the addition polymerization resin particles include emulsion polymerization, suspension polymerization, and dispersion polymerization. Further, a production method such as seed polymerization may be used. In this case, fine particles having a core-shell type structure are obtained, and the fine particles can also be used. Also, JP-A-5-43608, JP-A-5-222267, JP-A-7-18003, and JP-A-7-2286
No. 77, for example, may also be used.

On the other hand, as a method for producing polycondensation resin particles, for example, JP-A-5-70600 and JP-A-7-70600
No. 2,486,639 or the method described in
Preference is also given to the in-liquid drying method described in No. 5664 and the like.

In the case of the above-mentioned addition-polymerized resin fine particles, the monomer constituting the organic fine particles is not particularly limited, and includes a conventionally known monomer component. Those described in the publications mentioned are mentioned. Specifically, it is as follows. The monomer components can be used alone or in combination. Examples of the vinyl monomer include alkene compounds such as ethylene and propylene, and examples of the styrene monomer include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, Alkyl-substituted styrene having an alkyl chain such as -methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, vinylnaphthalene, and halogen-substituted styrene such as 2-chlorostyrene, 3-chlorostyrene and 4-chlorostyrene And fluorinated styrene such as 4-fluorostyrene and 2,5-difluorostyrene.

Examples of (meth) acrylic acid monomers include (meth) acrylic acid, n-methyl (meth) acrylate, n-ethyl (meth) acrylate, n-propyl (meth) acrylate, N-butyl (meth) acrylate,
N-pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, n- (meth) acrylate
Decyl, n-dodecyl (meth) acrylate, n-lauryl (meth) acrylate, n-tetradecyl (meth) acrylate, n-hexadecyl (meth) acrylate, n-octadecyl (meth) acrylate, (meth) Isopropyl acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, isopentyl (meth) acrylate, amyl (meth) acrylate, neopentyl (meth) acrylate, isohexyl (meth) acrylate,
Isoheptyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, phenyl (meth) acrylate, biphenyl (meth) acrylate, diphenylethyl (meth) acrylate,
T-butylphenyl (meth) acrylate, terphenyl (meth) acrylate, cyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate,
Dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, methoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth) acrylonitrile, (meth) acrylamide, and the like.

Other crosslinkable vinyl monomer components include, for example, diene compounds such as isoprene and butadiene; aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; ethylene glycol diacrylate and 1,3-butylene glycol diene. Acrylate,
Alkyl such as 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and those obtained by replacing the acrylate of the above compound with methacrylate Diacrylate compounds linked by a chain; diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and the above compounds Diacrylate compounds linked by an alkyl chain containing an ether bond, such as methacrylate instead of acrylate;

Polyoxyethylene- (2) -2,2, bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene- (4) -2,2-bis (4-
(Hydroxyphenyl) propane diacrylate and diacrylate compounds linked by a chain containing an aromatic group and an ether bond, such as those obtained by replacing the acrylate of the above compound with methacrylate. As the agent, for example, pentaerythritol triacrylate, trimethylol methane triacrylate,
Preferable examples include trimethylolpropane triacrylate, tetramethylol methanetetraacrylate, oligoester acrylate, and those obtained by replacing the acrylate of the above compound with methacrylate.

Of the above, (meth) acrylic acid having a carboxyl group, a hydroxyl group, an amide and the like, (meth) acrylic acid
Since 2-hydroxyethyl acrylate, acrylamide, and the like have high solubility in an aqueous medium, when they are used as an aqueous medium for the continuous phase, they may form ultrafine particles by themselves, and therefore, they are dispersed. It is preferable to select the type of the emulsifier or the emulsifier, or to use these monomers beforehand, alone or after being polymerized with other monomers to a molecular weight of about several thousands or less.

In the case of the above-mentioned polycondensation resin fine particles, the monomer constituting the organic fine particles is not particularly limited.
Examples of conventionally known monomer components include divalent or trivalent or higher carboxylic acids and divalent or trivalent or higher alcohols, and those described in publications describing the method for producing the polycondensation-based resin particles. Can also be used. Specifically, it is as follows.

Examples of the divalent carboxylic acid include succinic acid, glutaric acid, adipic acid, speric acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid and naphthalene. Dibasic acids such as -2,7-dicarboxylic acid, cyclohexanedicarboxylic acid, malonic acid and mesaconic acid, and their anhydrides and lower alkyl esters thereof, and aliphatic acids such as maleic acid, fumaric acid, itaconic acid and citraconic acid And unsaturated dicarboxylic acids. Examples of the trivalent or higher carboxylic acid include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,2
Examples thereof include 4-naphthalenetricarboxylic acid and the like, and anhydrides and lower alkyl esters thereof. These may be used alone or in combination of two or more.

Examples of the dihydric alcohol include bisphenol A, hydrogenated bisphenol A, ethylene oxide or (and) propylene oxide adduct of bisphenol A, 1,4-cyclohexanediol, 1,4
-Cyclohexane dimethanol, ethylene glycol,
Diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-
Butanediol, 1,5-pentanediol, 1,6-
Hexanediol, neopentyl glycol and the like can be mentioned. Examples of the trivalent or higher alcohol include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. These are 1
Species may be used alone or in combination of two or more. If necessary, a monovalent acid such as acetic acid or benzoic acid or a monohydric alcohol such as cyclohexanol or benzyl alcohol can be used for the purpose of adjusting the acid value or the hydroxyl value.

The method (4) includes, for example, emulsion polymerization, using an organic compound having an acyl group as a monomer.
Conventionally known polymerization granulation methods such as suspension polymerization and dispersion polymerization can be used. Examples of the raw material monomer include a vinyl compound having an acyl group, an epoxide, a cyclic acid anhydride, a cyclic amide, a cyclic ester, and the like. These monomers alone or a copolymer of the monomer and a monomer having no acyl group are used. By the coalescence, fine particles having an acyl group on the surface are synthesized.

The inorganic or organic fine particles having an acyl group on the surface obtained by the above four production methods may be used alone or in combination of two or more. When using organic fine particles,
From the viewpoint of eliminating the fluidity during heating in the later-described toner manufacturing process, a toner having heat resistance is preferable. Here, the deformation of the fine particles is allowed. That is, when the organic fine particles flow due to heat, the viscoelasticity of the toner deviates from the range specified in the present invention, and it becomes difficult to re-disperse when the particles are aggregated. Therefore, as the organic fine particles, those in which a crosslinked structure is formed using a trivalent or higher-valent monomer, or when having substantially no crosslinked structure,
The melting point or glass transition temperature of organic fine particles is 130 ° C
The above are preferred. The melting point is 150 ° C
The above is more preferable.

Next, dispersion of the fine particles in the toner,
The effect of the dispersion on the viscoelastic properties of the toner will be described. In the electrophotographic color toner of the present invention, the number of toner particles containing fine particles having a particle diameter of 1.0 μm or more is preferably 50% or less of the total number of toner particles in the electrophotographic color toner. This is because, in the entire toner, the number of fine particles of primary particles of 1.0 μm or more is small,
And that there are few secondary particles having a diameter of 1.0 μm or more (hereinafter, sometimes referred to as “aggregates”) generated by aggregation of primary particles having an average particle diameter of less than 1.0 μm. That is, usually, when fine particles are dispersed in toner, an aggregate is formed.
If the number of toner particles containing fine particles of m or more is 50% or less, it can be said that the fine particles are uniformly dispersed in the toner.

The above-mentioned “50% of toner particles containing fine particles having a particle diameter of 1.0 μm or more in all toner particles
"Below" means that the toner is transmitted through a transmission electron microscope (TE).
M) or a scanning electron microscope (SEM), one randomly extracted toner particle was photographed at a magnification of 30,000 times, and this was performed 50 times, that is, for 50 toner particles. It can be calculated by counting the number of toner particles containing particles having a maximum length of 1.0 μm or more as fine particles from the 50 photographs.

By uniformly dispersing the fine particles in the toner, it is possible to improve the melt viscosity characteristics of the toner that penetrates into the gaps of the paper fibers. The reason for this is not clear, but he speculates as follows. That is, the gaps between the fibers of the paper vary depending on the type thereof, but generally the gaps have a distribution in size, and have a pore diameter of about 0.1 to 10 μm. Above all, those having a size of several μm or more may be considered as surface irregularities rather than gaps, and those having a problem due to the penetration phenomenon are considered to be mainly 1 μm or less. At the time of fixing, the toner is crushed by heat and pressure, and the toner melted in the gap flows, and easily enters the gap. However, if the fine particles are contained in the toner particles, the fine particles become resistance and hinder the flow of the melted toner to suppress the permeation. Generally, in the field of rheology, when a high-viscosity fluid contains fine particles, it is known that when the fluid flows through a narrow tube, the flow is greatly disturbed. It is presumed that the same phenomenon occurs in the phenomenon of seepage into the gap. Therefore, when the toner flows in the narrow tube, it is considered preferable that a plurality of fine particles exist in the cross section of the tube.

For the reasons described above, it is essential that the fine particles are uniformly dispersed in the toner. When the number of toner particles including fine particles having a particle diameter of 1.0 μm or more in all the toner particles exceeds 50%, when the toner flows through the thin tube, the flow of the melted toner without much fine particles in the thin tube Cannot be inhibited, and it is difficult to obtain the effect of preventing permeation. In addition, such coarse particles also hinder the fixing property, so that the smoothness of the image after fixing is impaired, the color is not sufficiently formed, and the sharpness of the image is lost. fact,
In the observation by photographing, the effect of preventing the penetration phenomenon was higher as the amount of particles having a particle size of 1.0 μm or more in the toner was smaller.

In particular, the number of toner particles containing fine particles having a particle diameter of 1.0 μm or more in all the toner particles is more preferably 40% or less, and most preferably 30% or less.

As a method of uniformly dispersing the fine particles in the toner, a method of modifying the surface of the fine particles with a silane coupling agent or the like to prevent agglomeration, a method of dispersing using a powerful kneader, and the like are available. Although the former method,
It is difficult to completely prevent agglomeration of particles of the order of 0.1 μm, and it is also difficult to loosen once agglomerated particles by the latter method. However, by repeating a series of operations of kneading, cooling, coarse pulverization and re-kneading a plurality of times, the dispersibility of the fine particles can be improved to some extent. Further, the dispersibility of the fine particles can be improved to some extent by a method using a surfactant or a dispersant made of a polymer material in combination.
Above all, as a method for improving the dispersibility of the fine particles, a method of moistening the fine particles with water or a solvent and then kneading the fine particles in a binder resin (hereinafter, may be referred to as a “wet dispersion method”) is preferable. is there. As the wet dispersion method, for example, the following method is more preferable.

That is, first, a liquid that hardly swells or dissolves the fine particles (eg, water, alcohol, etc.) is added to the fine particles by dropping or spraying. The fine particles whose surface is wet with liquid are added to a binder resin heated and melted at a temperature of about 80 to 180 ° C. in a kneader such as a kneader capable of heating and kneading, and the fine particles are converted from the liquid phase to the binder resin phase. Then, the liquid is removed, dried and dispersed. This method (hereinafter sometimes referred to as “flushing treatment method”) can be suitably used as a wet dispersion method.

The above-mentioned flushing method is a method conventionally used for dispersing a pigment, but can also be suitably used for dispersing fine particles. Further, in the flushing treatment method, since fine particles are present in the liquid and the potential between the particles can be significantly reduced as compared with that in the air, the aggregation can be released with a very small external force, and the surface activity can be further improved. When an agent or the like is used, re-aggregation may be prevented in some cases. From the same effect, the following method can also be suitably used.

That is, for example, fine particles are added to a solvent such as THF or toluene and dispersed by an ultrasonic disperser or a sand mill. The solvent containing the fine particles is mixed with a binder resin or a solution in which the binder resin is previously dissolved, and the binder resin is dissolved in the solvent containing the fine particles. Thereafter, the obtained solution is placed under reduced pressure, and the solvent in the solution is removed, whereby the fine particles are dispersed in the binder resin. This method (hereinafter sometimes referred to as a “solvent treatment method”) can be suitably used because the same effects as those of the above-mentioned flushing treatment method can be obtained.

When organic fine particles are used as the fine particles, the use of the above-mentioned flushing method is optimal because the use of a solvent tends to cause the organic fine particles to swell or dissolve. When inorganic fine particles are used as the fine particles, it is preferable to use a solvent treatment method.

As described above, the average primary particle diameter of the fine particles is preferably 1 to 500 nm in view of the fact that a plurality of fine particles are preferably present in the cross section of the tube in consideration of the case where the toner flows through the thin tube. The upper limit is
It is more preferably at most 300 nm, most preferably at most 200 nm. When the average primary particle diameter exceeds 500 nm, the effect of preventing the penetration phenomenon is reduced, and the fixability is impaired, the smoothness of the image is impaired, and a clear image may not be obtained. In addition, the smaller the average particle diameter of the fine particles, the higher the effect of preventing the penetration of the toner. However, from the viewpoint of the productivity and handling of the particles, the particle diameter is more preferably 5 nm or more.

In the color toner for electrophotography of the present invention, the ratio of the fine particles contained in the toner can be represented by a volume fraction Φ in consideration of the specific gravity of the fine particles. The effective range of the volume fraction Φ varies depending on the average particle diameter of the fine particles. In the present invention, the range represented by the following formula (7) is preferable, and the range represented by the following formula (7-a) is preferable. The range represented by the following formula (7-b) is more preferable. 0.015D ^0.4 <Φ <0.5 Expression (7) 0.02D ^0.4 <Φ <0.4 Expression (7-a) 0.022D ^0.4 <Φ <0.4 Expression (7-b) wherein D represents the average particle size of the primary particles. ]

In the above equation (7), the volume fraction Φ is 0.015
If it is D ^0.4 or less, it may be difficult to exhibit the effect of preventing the penetration phenomenon, and if it is 0.5 or more, the fixing temperature may increase and the fixability may deteriorate. Generally, there is a relationship between the average particle diameter and the content of the fine particles, and the smaller the average particle diameter, the more the effect can be obtained even if the content is smaller. That is,
Φ is desirably appropriately determined within the above range in consideration of the material of the binder resin and the fine particles and other additives so as not to deteriorate the toner characteristics other than the fixing property.

By uniformly dispersing the fine particles in the toner so as to obtain the above-mentioned dispersion state, the melting characteristics and solid physical properties of the toner can be changed. The details will be described below. By incorporating fine particles into the toner with good dispersibility, the temperature dependence of the dynamic complex elastic modulus showing the viscoelastic properties of the toner becomes mild, and the toner starts to penetrate until the dynamic complex elastic modulus of about 3000 Pa is reached. Is hard to lower and the fixing start temperature is 10,000
When the dynamic complex elastic modulus is about Pa, it becomes viscous and easily crushed, and color development and fixing become easy, which is suitable for forming a color image.

On the other hand, if the molecular weight of the binder resin is increased without containing the fine particles to obtain the same viscoelastic temperature change, the binder resin becomes a resin having a molecular weight that is about one order of magnitude larger. The loss tangent (= loss modulus G ″ / storage modulus G ′, tan δ) is too small, or the dynamic complex modulus is too high, making it difficult to color and fix a color image. In the case of resin alone, the relationship between temperature and viscoelasticity is almost uniquely determined only by the relaxation process of polymer chains, whereas in the case of resin containing fine particles, the Since it varies not only with chains but also with the type, content, and dispersion state of the fine particles, the viscoelasticity can be controlled independently and flexibly as compared with the case of only the resin, even if the temperature change is the same. Therefore, it is possible to achieve both the expansion of the fixing temperature range and the low-temperature fixing property, which are the objects of the present invention, and the prevention of the toner from penetrating into plain paper. In this sense, viscoelastic properties are very important in adapting a toner containing fine particles to a color toner.

Further, the surface of the fine particles comes into direct contact with the polymer molecules constituting the binder resin, and in some cases, interaction occurs between the surface of the fine particles and the polymer molecules. Since this interaction affects the viscoelastic properties of the binder resin containing the fine particles, the composition of the surface of the fine particles is also very important. As described above, in the electrophotographic color toner of the present invention, fine particles having an acyl group on the surface are used, and the acyl group strongly interacts with the polymer molecules constituting the binder resin. Because of the induction, the temperature dependence of the dynamic complex elastic modulus of the binder resin due to the addition of fine particles can be effectively reduced, and as a result, the effect of preventing permeation works more effectively.

In the present invention, as described above, both the expansion of the fixing temperature range and the low-temperature fixing property can be achieved, and the phenomenon of toner penetration into the paper when using paper other than dedicated paper such as plain paper. In order to achieve the prevention, it is preferable that a state in which a plurality of fine particles exist in the inside of the thin tube is considered in consideration of the state in which the toner flows in the thin tube, and also from the viewpoint of rheological properties suitable for pure color toner. The electrophotographic color toner must satisfy the following viscoelastic condition (1).
That is,

The dynamic complex modulus G ^{* of} the binder resin used in the toner (strain rate = 100%, frequency = 10 rad / s)
The dynamic complex elastic modulus G ^* (strain rate = 100%, frequency = 10 rad / sec) of the toner particles measured at a temperature where ec) indicates 1000 Pa is 3000 to 50,000 P
a [viscoelastic condition (1)]. The viscoelastic condition (1)
The dynamic complex elastic modulus G ^* of the toner particles at
000-20,000 Pa is preferable. In order for the toner particles to satisfy the viscoelasticity condition (1), it is preferable that fine particles are dispersed and contained in the binder resin so as to obtain the above-described favorable dispersion state.

The viscoelasticity condition (1) is an index indicating how much the viscoelasticity of the toner dropped into the fibers in the paper when forming the unfixed image can be prevented at the time of fixing. . Therefore, the dynamic complex modulus G ^* is
The higher the value, the more the phenomenon of penetration of the toner into the paper can be prevented ^. However, if the G ^* exceeds 50,000 Pa, the toner may not be able to adhere to the paper.
If the pressure is less than 000 Pa, a penetration phenomenon may occur.

FIG. 1 shows the relationship between the dynamic complex elastic modulus G ^* of an electrophotographic color toner and temperature. From FIG. 1, it can be seen that the toner satisfying the viscoelastic condition (1), that is, the fine particle-containing toner in which fine particles are well dispersed (solid line in FIG. 1) shows the temperature dependence of the viscoelastic characteristics (the dynamic complex elastic modulus of the toner). G ^* ) is gentle with respect to the temperature change, does not drop until around 3000 Pa at which toner penetration starts, and the dynamic complex elastic modulus G ^* is constant in a region of about 10,000 Pa at which fixing starts. , Viscous and easily crushed,
It can be seen that color development and fixing can be easily performed, which is suitable for forming a color image.

By satisfying the above viscoelastic condition (1), it is possible to achieve both the expansion of the fixing temperature range and the low-temperature fixing property, and the use of toner paper when using paper other than specialty paper such as plain paper. Penetration into the inside can be effectively prevented. As a result, a clear, high-quality image with high density can be stably formed.

The electrophotographic color toner of the present invention preferably further satisfies the following viscoelastic conditions (2) and (3). The viscoelastic conditions (2) and (3) can be achieved by dispersing fine particles in a binder resin so as to obtain a favorable dispersion state as described above. That is,

[Viscoelastic Condition (2)] Dynamic complex elastic modulus G ^{* of the} binder resin (strain rate = 100%, frequency = 10 rad /
It is preferable that the frequency dependence of the dynamic complex elastic modulus G ^* (strain rate = 10%) of the toner measured at a temperature at which sec) is 1000 Pa satisfies the following expression (8). G ^* (100 rad / sec) / G ^* (1 rad / sec) <10 Expression (8)

The viscoelastic condition (2) is an index indicating in which temperature range the relaxation process due to the dispersion of the fine particles is present and the elastic modulus is effective. Therefore, the viscoelastic condition (2) indicates that the frequency dependence of the viscoelasticity is small, and indicates that a unique viscoelastic relaxation process exists.
In the case of a toner that does not have a sufficient or low viscoelastic relaxation process, such as a toner that does not contain fine particles or a toner that has poor dispersibility of fine particles, both the frequency dependence and the temperature dependence of viscoelasticity increase. Would. The G ^* (100
When the value of rad / sec) / G ^* (1 rad / sec) is large, it indicates that the relaxation due to the dispersion of the fine particles is not effectively present. Therefore, the value is more preferably 7 or less, and most preferably 5 or less. .

[Viscoelastic Condition (3)] Further, the dynamic complex elastic modulus G ^{* of} the binder resin (strain rate = 100%, frequency = 10
The tan δ in the dynamic viscoelasticity of the toner, measured at a temperature at which the rad / sec) is 1000 Pa, is preferably 1.1 or more. The viscoelasticity condition (3) is an index indicating the ease with which the toner is crushed during fixing.
When the tan δ is less than 1.1, the glossiness of the image is impaired, and the color development may be insufficient.

The measurement of the viscoelastic conditions (1) to (3) is as follows.
For example, it can be easily measured using a rheometer (RDA2 (RHIOS system Ver. 4.3), manufactured by Rheometrics).

In the conventional electrophotographic color toner, the glass transition temperature is about 60 ° C. or higher and the melting temperature T
Unless a binder resin having m of 100 ° C. or more was used, the above-described blocking phenomenon and document offset phenomenon could not be suppressed. However, in the electrophotographic color toner of the present invention, as described above, by using the fine particles having an acyl group on the surface, the glass transition temperature is 40 to 60 ° C and the melting temperature Tm is 60 to 90 ° C. Even when the resin is used, it has an effect of suppressing a blocking phenomenon and a document offset phenomenon in a solid state from a room temperature to a temperature close to a glass transition temperature, enables low-temperature fixing, and enables fixing with energy saving. The reason is considered as follows.

That is, the heat blocking starts when the low molecular weight component of the binder resin existing near the surface of the toner particles diffuses and moves, thereby bonding the toner particles together, and bonding the toner image and the paper or toner image. It seems to do,
In the color toner for electrophotography of the present invention, it is considered that the fine particles dispersed in the binder resin suppress the diffusion and movement of the low molecular component of the binder resin and prevent the heat blocking. The fine particles suppress the diffusion of the surrounding solvent molecules,
Alternatively, the idea of constraining exists in other material systems and has been shown in the literature, for example, due to the presence of fine particles,
In describing the rheological behavior of an aqueous dispersion of fine particles, the effect of making the fine particles larger than the actual particle size by the hydration layer is considered.

In the color toner for electrophotography of the present invention, since the distance between the surfaces of the fine particles is very close to about 10 to 50 nm, a large amount of molecules of the binder resin are present near the surface of the fine particles. It is presumed that the above-mentioned effects appear because these are bound by the particles due to intermolecular interaction or the like. This is a technique in which minute projections are present on the surface to avoid surface contact with other particle surfaces and make point contact. However, fine particles of 500 nm or more have little effect on heat blocking between toner particles, and are not suitable for color images because the image smoothness is not improved.

Therefore, in the electrophotographic color toner of the present invention, the average primary particle diameter of the fine particles is 50.
0 nm or less is preferable, 1 to 300 nm is more preferable, and 5 to 200 nm is most preferable. The average primary particle diameter is, for example, a transmission electron microscope (TEM), or
It can be measured by using a scanning electron microscope (SEM) and measuring from the image thereof.

From the viewpoint of improving the heat preservability of the toner powder, the fine particles preferably contain fine particles having different average particle diameters.
It is suitable to include fine particles having other average particle diameters together with fine particles of 200 nm, preferably 30 to 150 nm. As the fine particles having the other average particle diameter, when the average particle diameter is smaller than 30 to 200 nm, the average particle diameter is 1 to 30 nm, preferably 5 to 30 nm.
of fine particles having an average particle diameter of 30 to 20 nm.
In the case of fine particles larger than 0 nm, the average particle size is 20 nm.
Fine particles of 0 to 300 nm are preferred.

In order to sufficiently bring out this effect, it is preferable to further use a low melting point lubricant. The low melting point lubricant exudes to the image surface in the fixing step, and
A 0 nm film is formed. The formed film has a function of further blocking the diffusion and movement of the low molecular component of the binder resin, which is suppressed by the fine particles, as described above.
Even under severe conditions where the temperature is slightly higher than g and the melting temperature Tm, the blocking phenomenon and the document offset phenomenon can be suppressed.

(Binder Resin) Next, the binder resin that can be used in the electrophotographic color toner of the present invention will be described. Examples of the composition of the binder resin include: ethylene resins such as polyethylene and polypropylene; styrene resins such as polystyrene and α-polymethylstyrene; (meth) acrylic resins such as polymethyl methacrylate and polyacrylonitrile; polyamide resins; Polycarbonate resins, polyether resins, polyester resins, and copolymer resins thereof, and the like. Among them, styrene resins, (meth) acrylic resins, Styrene- (meth) acrylic copolymer resins and polyester resins are preferred. Further, from the viewpoints of low-temperature fixability and resistance to adhesion of vinyl chloride to images, polyester resins are more preferable.

As the monomers constituting the styrene resin, the (meth) acrylic resin and the copolymer resin thereof, the addition polymerization monomers constituting the organic fine particles described above are preferable. However, since a large amount of the cross-linking component may impair the color development of the toner, the cross-linking component is 5 mol% by weight.
% Is preferably used. These monomers can be appropriately combined and produced by a conventional method.

The polyester resin is preferably an amorphous polyester resin. The amorphous polyester resin is advantageous in that unlike the crystalline polyester resin, the resin itself does not become cloudy due to light scattering by crystals. In the present invention, the term “amorphous polyester resin” refers to a crystalline melting point in addition to an endothermic point corresponding to Tg in a measurement chart obtained from a differential scanning calorimeter (hereinafter abbreviated as “DSC”). Means a polyester resin which does not show the above endothermic peak.

In addition to the above, as the other monomer usable for the polyester resin, a polycondensation type monomer constituting the organic fine particles is preferable, and as in the case of the addition polymerization type monomer, trivalent or higher. The amount of the crosslinkable monomer is preferably 5 mol% or less of the total amount of the monomers.

The polyester resin may be appropriately combined from the above-mentioned monomer components, for example, polycondensation (chemical doujinshi), polymer experiments (polycondensation and polyaddition: Kyoritsu Shuppan) or polyester resin handbook (Nikkan Kogyo Shimbun) Ed.), Etc., and can be synthesized by a conventionally known method. Specifically, a transesterification method, a direct polycondensation method, or the like is used alone.
Alternatively, they can be used in combination.

It is preferable that the above-mentioned binder resin contains substantially no THF-insoluble matter irrespective of styrene type, acrylic type or polyester type. When the THF-insoluble matter is contained, the offset resistance is improved, but on the other hand, the glossiness of the image is impaired and the OHP light transmittance is impaired. The THF-insoluble content can be measured by dissolving the resin in THF at a concentration of about 10% by weight, filtering the solution with a membrane filter or the like, drying the filter residue, and measuring the weight.

The glass transition temperature Tg of the binder resin is preferably from 40 to 100 ° C., more preferably from 45 to 85 ° C., and most preferably from 50 to 75 ° C. The Tg is 4
When the temperature is lower than 0 ° C., the toner may be easily blocked by heat, and when the temperature is higher than 100 ° C., the fixing temperature may be too high. The Tg is, for example, DSC
Measurement can be performed with a temperature rising rate of 5 ° C./min using -6200 (manufactured by Seiko Instruments Inc.) or the like. can do.

The melting temperature Tm of the binder resin is 6
The temperature is preferably from 0 to 100C, more preferably from 60 to 90C, and most preferably from 60 to 80C. The Tm is 60 ° C.
If the temperature is less than 100 ° C., a blocking phenomenon or a document offset phenomenon may easily occur. If the temperature exceeds 100 ° C., the fixing temperature may be too high, and it may be difficult to perform energy-saving fixing.

The molecular weight of the binder resin may be styrene resin, (meth) acrylic resin, styrene- (meth)
In the case of acrylic resin, the weight average molecular weight (hereinafter, referred to as
Abbreviated as "Mw". ) And number average molecular weight (hereinafter referred to as “M
n ". ) Is preferably in the following range. That is, the Mw is 30,000 to 10,000
0 is preferable, and 35,000 to 80,000 is more preferable. The Mn is preferably 2,000 to 30,000, more preferably 2,500 to 20,000. In the case of a polyester resin, Mw is 5,000 to 3
0000 is preferable, 6000 to 20,000 is more preferable, and Mn is preferably 2,000 to 8000,
2500-6000 is more preferred.

If Mw and Mn are too high, the minimum fixing temperature may increase, and if it is too low, it may be difficult to obtain image strength after fixing. Further, the binder resin preferably has an acid value of 10 to 50 KOHmg / g from the viewpoint of excellent chargeability.

The molecular weight and the molecular weight distribution can be measured by a method known per se, and generally, gel permeation chromatography (hereinafter, “GPC”)
Abbreviated. ) Can be measured. The GPC measurement is performed, for example, using an HL manufactured by TOYO SODA
Using C-802A, an oven temperature of 40 ° C., a column flow rate of 1 ml per minute, and a sample injection amount of 0.1 ml can be carried out. A 0.5% concentration of THF for GPC (manufactured by Wako Pure Chemical Industries, Ltd.) can be obtained. It can be done as a sample.
The calibration curve can be created, for example, using a standard polystyrene sample manufactured by TOYO SODA.
The molecular weight and the molecular weight distribution of the binder resin in Examples described later of the present invention were measured as described above.

The electrophotographic color toner of the present invention contains fine particles in the toner with good dispersibility. Therefore, even when a binder resin having a low glass transition temperature Tg and a low melting temperature Tm is used, the above-mentioned blocking phenomenon and the like can be prevented. The document offset phenomenon can be suppressed, and when a low melting point lubricant is further contained, the blocking phenomenon and the document offset phenomenon can be suppressed more effectively. For this reason, the electrophotographic color toner of the present invention containing the low-melting lubricant together with the fine particles, even as a toner that can be fixed under oil-less conditions, retains good releasability and has a low fixing temperature at the time of fixing. Can be achieved.
When fixing under oil-less conditions, it is necessary to ensure not only the hot offset resistance of the toner but also the resistance to wrapping around the fixing device (avoid the phenomenon of wrapping the entire sheet of paper with the toner layer as an adhesive layer). However, it is not sufficient that the releasing effect alone is sufficient, and it is preferable that the binder resin constituting the toner has specific viscoelastic properties.

As the viscoelastic properties of the binder resin for obtaining good winding resistance, it is necessary to suppress the energy loss due to the viscous deformation in the peeling deformation, that is, the glass transition temperature of the binder resin and the loss elasticity. Rate G ″ = 1 × 10
It is preferable that the tan δ in the dynamic viscoelasticity of the binder resin has a minimum value at a temperature between ⁴ Pa · s and the minimum value is less than 1.2. The peeling deformation of the toner when peeling off from the surface of the fixing device is as follows. Since the thickness of the formed toner image is as thin as about 10 μm, the actual peeling deformation speed of the toner becomes extremely high, and the temperature of viscoelasticity and the time conversion rule Therefore, the viscoelasticity of the binder resin in the vicinity of the latter half of the glass transition temperature greatly affects the peeling deformation.

To obtain such viscoelastic properties, the binder resin preferably has a weight average molecular weight of 15,000 to 20,000 in the case of a polycondensation resin, and 40,000 to 60,000 in the case of a vinyl resin. It is preferable that the molecular weight be 1.5 times or more the molecular weight of a resin suitable for fixing using oil. Therefore, the fixing temperature inevitably increases. However, as described above, even if the glass transition temperature and the melting temperature of the binder resin are lowered, good resistance to the blocking phenomenon and the document offset phenomenon can be obtained.

Next, the colorant constituting the electrophotographic color toner of the present invention and other components other than the fine particles, the binder resin and the colorant will be described. (Colorant) The colorant is not particularly limited, and may be a known colorant, and may be appropriately selected according to the purpose. Examples of the colorant include, for example, carbon black, lamp black, aniline blue, ultramarine blue, calcoil blue, methylene blue chloride, copper phthalocyanine, quinoline yellow, chrome yellow, Dupont oil red, orient oil red, rose bengal, malachite green Oxalate, nigrosine dye, C.I. I. Pigment Red 4
8: 1, C.I. I. Pigment Red 57: 1, C.I. I.
Pigment Red 81: 1, C.I. I. Pigment Red 122, C.I. I. Pigment Yellow 97, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 1
7, C.I. I. Pigment Blue 15: 1, C.I. I. Pigment Blue 15: 3 and the like.

The content of the colorant in the electrophotographic color toner is preferably 1 to 30 parts by weight with respect to 100 parts by weight of the binder resin, but does not impair the smoothness of the image surface after fixing. It is preferable that the number be as large as possible in the range. When the content of the coloring agent is increased, the thickness of the image can be reduced when an image having the same density is obtained, which is advantageous in that it is effective in preventing offset. In addition,
Depending on the type of the colorant, a cyan toner, a magenta toner, a yellow toner, a black toner, and the like can be obtained.

(Other Components) The other components are not particularly limited and may be appropriately selected according to the purpose. For example, various known additives, such as an internal additive such as a low melting point lubricant and a charge controlling agent, and an external additive such as other inorganic fine particles and other organic fine particles, may be used. The low melting point lubricant is generally used for the purpose of improving offset resistance, and specifically, wax,
Higher fatty acids (eg, stearic acid, montanic acid, etc.),
Fatty acid metal salts (eg, calcium stearate, zinc stearate, magnesium stearate, calcium laurate, etc.), higher alcohols (eg, stearyl alcohol, etc.) and the like can be mentioned. Above all, wax is preferable in that chargeability control is easy.

Examples of the wax include aliphatic hydrocarbon waxes (eg, low molecular weight polyethylene having a branched structure in the molecule, low molecular weight polypropylene, microcrystalline wax, tetratetracontan, octacontan, paraffin wax), and modified waxes. Aliphatic hydrocarbon-based wax (for example, modified polyethylene-based release agent described in JP-A-9-134035), carnauba wax, candelilla wax, rice wax, sasol wax, aliphatic wax (E.g., montanic acid esters), deoxidized aliphatic waxes, silicone resins, rosins, and the like.
A temperature of 110 ° C. is more preferable.

The wax is also used from the viewpoint of suppressing the above-described blocking phenomenon and document offset phenomenon.
The melting point is preferably 100 ° C. or less, and the content is preferably based on the total weight of the electrophotographic color toner.
It is preferably from 3 to 10% by weight, more preferably from 3 to 7% by weight. If the content of the wax is too large, the wax on the surface or inside of the color-fixed image deteriorates the OHP projection property. When the wax is used as a two-component developer, the wax is transferred to the carrier by rubbing between the toner and the carrier. As a result, the charging performance of the developer changes over time. Similarly, when the developer is used as a one-component developer, the wax is transferred to the blade by the rubbing of the toner and the blade for applying the charge, so that the wax is transferred to the blade. The color image quality and the reliability may be deteriorated, for example, the charging performance changes over time, and the wax deteriorates the fluidity of the toner.

Examples of the other inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, Diatomaceous earth, cerium chloride, red iron oxide, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, silicon nitride, and the like, among which titanium-based fine particles and silica fine particles are preferable, and further, a hydrophobic treatment Fine particles are more preferred.

The inorganic fine particles are generally used for the purpose of improving fluidity. The primary particle size of the inorganic fine particles is preferably from 1 to 1000 nm, and the amount of the inorganic fine particles is preferably 100 parts by weight based on 100 parts by weight of the electrophotographic color toner.
0.01 to 20 parts by weight is preferred.

The other organic fine particles are generally used for the purpose of improving the cleaning property and the transfer property, and specific examples thereof include polystyrene, polymethyl methacrylate, and polyvinylidene fluoride. Further, those obtained by treating the surfaces of these fine particles with a silicone compound or a fluorine compound can also be suitably used.

Examples of the charge control agent include salicylic acid metal salts, metal-containing azo compounds, nigrosine and quaternary ammonium salts. The charge control agent is generally used for the purpose of improving chargeability.

The method for producing the electrophotographic color toner of the present invention is not particularly limited, and it can be produced by appropriately selecting from known production methods according to the purpose. Examples of the production method include a kneading and pulverizing method, a kneading freezing and pulverizing method, a submerged drying method (Japanese Patent Laid-Open No. 63-25664), a method in which a molten toner is subjected to shear stirring in an insoluble liquid to form fine particles, A method in which a binder resin and a colorant are dispersed in a solvent to form fine particles by jet spraying;
239), among which the kneading and pulverizing method is preferable.

In the kneading and pulverizing method, a binder resin, a colorant and other additives are melted and kneaded using a Banbury-type kneader or a twin-screw kneader or the like, and are then mixed with a hammer mill or a jet-type pulverizer. The toner is obtained by performing pulverization and classifying with an inertial force classifier or the like, and is excellent in that the material efficiency is good and the toner can be manufactured at a low cost, and the additive can be internally added with relatively good dispersibility. I have. According to this method, the fine particles can be dispersed and internally added to the toner without aggregating.

<Electrophotographic Developer> The electrophotographic color toner of the present invention can be suitably used as a toner in an electrophotographic developer. The electrophotographic developer of the present invention may be a one-component electrophotographic developer containing at least the electrophotographic color toner of the present invention, or at least the electrophotographic color toner of the present invention and a carrier. And a two-component developer for electrophotography. The carrier is not particularly limited, and a well-known carrier, for example, a resin-coated carrier or the like is preferably used. The resin-coated carrier is obtained by coating the surface of a core material with a resin. Examples of the core material include magnetic powder such as iron powder, ferrite powder, and nickel powder.
Examples of the resin include a fluorine-based resin, a vinyl-based resin, and a silicone-based resin.

The electrophotographic developer of the present invention may contain additives and the like appropriately selected according to the purpose. For example, for the purpose of obtaining magnetism, iron, ferrite, irons including magnetite, metals exhibiting ferromagnetism such as nickel and cobalt, alloys or compounds containing these metals, magnetic materials, magnetizable materials are included. May be. Further, the electrophotographic developer of the present invention can be suitably used for various image forming methods.

<Image Forming Method> In the image forming method of the present invention, the electrophotographic developer of the present invention is used as an electrophotographic developer. Forming a latent image on the image carrier, developing the latent image using an electrophotographic developer to form a toner image, transferring the developed toner image onto a transfer-receiving member, and A step of fixing the toner image transferred onto the transfer member can be appropriately selected from the methods.

In the step of forming a latent image on the latent image holding member, for example, an electrophotographic photosensitive member or a dielectric recording material is used as the latent image holding member. The photoreceptor is uniformly charged by a corotron charger, a contact charger, or the like, and then imagewise exposed to form an electrostatic latent image.

In the step of developing the latent image using an electrophotographic developer to form a toner image, the latent image is brought into contact with or in close proximity to a developing roll having a developer layer formed on the surface thereof, and the toner is applied to the electrostatic latent image. The particles adhere to form a toner image on the electrophotographic photoreceptor. Here, an electrophotographic developer including the electrophotographic color toner of the present invention is used as the developer.

In the step of transferring the developed toner image onto the transfer member, the formed toner image is transferred onto a transfer member such as paper using a corotron charger or the like. In finally transferring the toner image onto the transfer object, first, the toner image may be transferred onto the intermediate transfer member, and the toner image transferred onto the intermediate transfer member may be further transferred onto the transfer member. . The intermediate transfer member may be a roller or a belt. Further, the transfer and the fixing may be performed simultaneously.

In the step of fixing the toner image transferred onto the transfer object, the transfer object on which the toner image has been transferred is passed through a fixing device, and is fixed while heating, pressing or heating and pressing to form an image. I do.

In the image forming method of the present invention, a heating contact type fixing device is used as a fixing device used for fixing a toner image. As the heating contact-type fixing device, for example,
A heating roller having a rubber elastic layer on the core metal, and a fixing member surface layer as necessary, and a rubber elastic layer on the core metal,
A heat roller fixing device comprising a pressure roller provided with a fixing member surface layer, if necessary, or a combination of the above-mentioned roller and roller, a combination of a roller and a belt, or a combination of a belt and a belt A heat belt fixing device may be used instead of the alignment.

In the image forming method of the present invention, it is possible to use a fixing device having a known release agent applying means, and to use a so-called oilless fixing device having no release agent applying means. Can be. In the case of using a fixing device provided with the release agent applying means, the supply amount of the release agent may be appropriately selected, but is preferably 2 mg / A4 or less.

For the rubber elastic layer in the heat contact type fixing device, heat resistant rubber such as silicone rubber or fluoro rubber is used, and the thickness is preferably 0.1 to 3 mm, and the rubber hardness is 60 mm. The following is preferred. By providing the rubber elastic layer on the roller serving as the fixing member, the fixing member is deformed following the unevenness of the toner image on the transfer object, and the smoothness of the image surface after fixing can be improved. When the thickness of the rubber elastic layer is too thick, the heat capacity of the fixing member increases, and it takes a long time to heat the fixing member, and the energy consumption thereof may increase. In addition, the deformation of the fixing member may not be able to follow the unevenness of the toner image, causing uneven melting, or the rubber elastic layer may not have effective distortion for peeling.

Silicone rubber,
Fluoro rubber and fluoro resin are used. Among them, fluororesins are excellent in terms of wear resistance. As the fluororesin, a resin containing a large amount of fluorine such as polytetrafluoroethylene (PTFE) or a copolymer of tetrafluoroethylene and perfluoroalkylvinyl ether (PFA) is preferable.

As the base material (core) of the fixing member, a material having excellent heat resistance, high strength against deformation, and excellent heat conductivity is selected. In the case of a roll-type fixing device,
For example, aluminum, iron, copper, and the like are selected. In the case of a belt-type fixing device, for example, a polyimide film, a stainless steel belt, and the like are selected.

The rubber elastic layer and the surface layer provided on the fixing member such as the roller may contain various additives depending on the purpose. May contain carbon black, metal oxides, ceramic particles such as SiC, or the like. The fixing member may be coated with a release agent such as silicone oil for the purpose of further improving the releasability and abrasion resistance. The release agent is not particularly limited, and examples thereof include liquid release agents such as heat-resistant oils such as dimethyl silicone oil, fluorine oil and fluorosilicone oil, and modified oils such as amino-modified silicone oil.

The transfer medium (recording material) includes, for example, plain paper and OHP sheets used in electrophotographic copying machines, printers, etc., from the viewpoint of more effectively preventing penetration. Particularly, those having a surface smoothness of 80 seconds or less are preferable. The surface smoothness is determined by JIS P
It is a value measured according to 8119. If it is desired to further improve the smoothness of the image surface after fixing, it is only necessary to use a surface having as smooth a surface as possible, for example,
Examples include coated paper in which the surface of plain paper is coated with a resin or the like, art paper for printing, and the like.

<Image Forming Apparatus> The specific configuration of the image forming apparatus usable in the image forming method of the present invention is as follows.
It is not particularly limited and can be appropriately selected from those having a known configuration. For example, the image forming apparatus may be an image forming apparatus (FIGS. 2 to 4) configured in the following first to third aspects, and each aspect will be described below.

(First Embodiment) In the first embodiment, for example, an image is formed as shown in FIG. 2, in which a toner image formed on a photoreceptor is directly transferred and formed on a transfer-receiving member. It is a forming device. FIG. 2 is a schematic configuration diagram illustrating an example of an image forming apparatus suitably used in the image forming method of the present invention. That is, developing devices 15a and 15b having the photoreceptor 11 and having around the photoreceptor 11, a cleaner 12, a charger 13, an exposure device 14, and electrophotographic developers of respective colors of cyan, magenta, yellow and black, 15c and 15d,
The transfer rolls 17 are arranged in this order. The photoconductor 11 rotates in the direction of the arrow in the figure. Transfer roll 1
A transfer charger 16 is provided inside the photoconductor 7 so as to face the photoconductor 11. A peeling claw 18 is provided around the transfer roll 17. Further, the toner image 10 transferred to the transfer target 21 by the transfer roll 17 is fixed in the rotation advancing direction of the transfer roll 17.
A pair of heat roll fixing machines including a heating roller 19 and a pressure roller 20 are provided.

In the image forming apparatus of this embodiment, an image is formed as follows. That is, the photoconductor 11 charged by the charger 13 is exposed by the exposure device 14 to form a latent image on the photoconductor 11. The latent images on the photoreceptor 11 are rotated in the directions indicated by the arrows while developing machines 15a, 15b, 15c, 15c.
d to form a toner image 10. On the other hand, the transfer roll 17 rotates in synchronization with the photoreceptor 11 in the direction of the arrow in the figure, and the developed toner image 10 is applied with a bias charge having a polarity opposite to the frictional charge of the toner by the transfer charger 16. The image is transferred onto the transfer body 21. After the transfer, the transfer target 21 is moved by the peeling claw 18
Is peeled off from the transfer roll 17. The toner image 10 on the transfer member 21 separated by the separation claw 18 is fixed on the transfer member 21 by passing the transfer member 21 between the heating roller 19 and the pressure roller 20, and an image is formed. It is formed. After transferring the toner image 10 on the photoreceptor 11 to the transfer target 21, the toner image 1 remaining on the photoreceptor 11
0 is removed by the cleaner 12.

(Second Aspect) The second aspect is, for example, as shown in FIG. 3, in which a toner image formed on a photoreceptor is temporarily transferred onto an intermediate transfer body and then transferred. This is an image forming apparatus that transfers an image to a body again to form an image. FIG. 3 is a schematic configuration diagram showing an example of an image forming apparatus suitably used in the image forming method of the present invention. That is, FIG.
Charging transfer device 16 and transfer roll 1 of the image forming apparatus shown in FIG.
7 and a peeling claw 18, a roll-shaped intermediate transfer member 22
And an image forming apparatus having the same configuration as that of FIG. 2 except that a transfer charger 23 is provided around the intermediate transfer body 22.

In the image forming apparatus of this embodiment, an image is formed as follows. That is, the photoconductor 11 charged by the charger 13 is exposed by the exposure device 14 to form a latent image on the photoconductor 11. The latent images on the photoreceptor 11 are rotated in the directions indicated by the arrows while developing machines 15a, 15b, 15c, 15c.
d to form a toner image 10. On the other hand, the transfer roll 17 rotates in synchronization with the photoconductor 11 in the direction of the arrow in the figure, and the developed toner image 10 is transferred onto the intermediate transfer body 22 in the form of a roll. Thereafter, the toner image 10 transferred onto the roll-shaped intermediate transfer member 22 is transferred to the transfer member 21 by applying a bias charge having a polarity opposite to the frictional charge of the toner by the transfer charger 23. Transferee 2
1 is a heating roller 19 at the same speed as the rotation of the transfer roll 17.
And a pressure roller 20, and is conveyed in the direction of a heat roll fixing machine. The toner image 10 on the transfer object 21 is
1 is passed between the heating roller 19 and the pressure roller 20 to be fixed on the transfer-receiving body 21 to form an image. Note that the toner image 10 on the photoconductor 11 is
Image remaining on the photoreceptor 11 after being transferred to
Is removed by the cleaner 12.

(Third Aspect) In the third aspect, for example, each of the toner images formed on four photosensitive members of cyan, magenta, yellow and black is constituted as shown in FIG. An image forming apparatus of a tandem structure, in which an image on which the four colors have been transferred is re-transferred onto a transfer receiving body after being transferred to the same position on a belt-shaped intermediate transfer body. FIG.
1 is a schematic configuration diagram illustrating an example of an image forming apparatus suitably used in the image forming method of the present invention. That is, the photoconductor 31
Around the photoreceptor 31, a cleaner 32, a charger 33, an exposure device 34, a developing device 35, and a transfer charger 36.
Are the developing units 37a, 37b arranged in this order,
37c and 37d are arranged in series. Each developing device 3 constituting the developing units 37a, 37b, 37c, 37d
Reference numeral 5 includes a developer for each color of cyan, magenta, yellow, and black. Developing units 37a, 37
A belt-shaped intermediate transfer member 38 is arranged between the photoconductor 31 constituting the transfer members b, 37c, and 37d and the transfer charger 36. The belt-shaped intermediate transfer body 38 is stretched between a heating spindle roller 40 having a heating element 39 built therein and a spindle roller 41. The heating spindle roller 40 is pressed by a pressure roller 42 via a belt-shaped intermediate transfer body 38.

In the image forming apparatus of this embodiment, an image is formed as follows. That is, the photoconductor 31 charged by the charger 33 is exposed by the exposure device 34 to form a latent image on the photoconductor 31. The latent image on the photoreceptor 31 is
5, the toner image 10 is formed. The developed toner image 10 is transferred to a belt-shaped intermediate transfer member 38 by applying a bias charge having a polarity opposite to the frictional charge of the toner by a transfer charger 36. Toner image 10 on photoconductor 31
Is transferred onto a belt-shaped intermediate transfer member 38, and then the photosensitive member 3
The toner image 10 remaining on 1 is removed by the cleaner 32. This series of operations is performed by the developing unit 37.
The transfer is sequentially performed in the order of a, 37b, 37c, and 37d, and the images are sequentially transferred at the same position on the belt-like intermediate transfer body 38 conveyed in the direction of the arrow. The heating spindle roller 40 rotates so that the toner image 10 on the intermediate transfer member 38 transferred by the developing units 37a, 37b, 37c, and 37d advances in the direction of the heating spindle roller 40. The toner image 10 on the belt-shaped intermediate transfer member 38 is gradually heated as the heating spindle roller 40 approaches, and melts when it reaches the position of the heating spindle roller 40. Belt-shaped intermediate transfer body 38
When the upper fused toner image 10 is passed between the heating spindle roller 40 and the pressure roller 42 pressed against the belt-like intermediate transfer member 38, the transfer member 43 is inserted. The toner image 10 is transferred and fixed on the transfer body 43 at the same time, and an image is formed.

As in the present embodiment, the thermal transfer method for transferring toner onto a transfer-receiving member, such as an apparatus for simultaneously performing transfer and fixing using a belt-type intermediate transfer member, is also applicable to the electrophotographic method of the present invention. Color toner can be suitably used. This is because the toner of the present invention has a yield value with respect to deformation and prevents the image from being displaced in a thermal transfer method in which the heating time is long and the conveyance is performed at a low pressure.

[0139]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples.
“Parts” and “%” in the examples indicate “parts by weight” and “% by weight”, respectively. <Production of Fine Particles Having Acyl Group on Surface> (Synthesis of Inorganic Fine Particles S-a1 Having Acyl Group) In a reaction vessel equipped with a stirrer having a plurality of stirring blades, a reflux condenser, a thermometer, and a nitrogen inlet tube, A fine particle dispersion prepared by adding 300 parts of synthetic silica powder A130 (manufactured by Nippon Aerosil Co., Ltd., average particle diameter = 16 nm) to 4000 ml of 2-propanol as a solvent, and a reactive group having an acyl group introduced therein And 85.9 parts (0.38 mol) of acetoxypropyltrimethoxysilane (manufactured by Gerest) shown below were added to obtain a mixed solution. After the inside of the reaction vessel was replaced with dry nitrogen gas, the temperature of the mixed solution was raised to about 80 ° C. while stirring under a stream of nitrogen gas. After the temperature was raised, 50 ml of 0.1 N hydrochloric acid was dropped as a catalyst, and the mixture was further stirred for about 6 hours. Reacted. After the stirring reaction, the mixed solution was taken out, and the treated fine particles were separated by centrifugation, mixed with ion exchanged water, stirred, and centrifuged again to repeat washing five times. Finally, water was removed by freeze-drying to obtain inorganic fine particles S-a1 having an acyl group on the surface.

[0140]

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(Synthesis of Inorganic Fine Particle S-a2 Having Acyl Group) The compound having an acyl group-introduced reactive group used in the synthesis of the inorganic fine particle S-a1 having an acyl group is shown below. 108.1 parts of propyltrimethoxysilane (manufactured by Gerest) (0.38 m
ol), except that the inorganic fine particle S-a2 having an acyl group is the same as in the case of the inorganic fine particle S-a1.
I got

[0142]

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(Synthesis of Organic Fine Particle Pa Having Acyl Group) Ion-exchanged water 9 was placed in a reaction vessel equipped with a stirrer having a plurality of stirring blades, a reflux condenser, a thermometer, and a nitrogen inlet tube.
20 parts were charged, and the inside of the reaction vessel was sufficiently purged with nitrogen. Thereafter, 25 parts of vinyl acetate shown below as an acyl group-containing monomer, a mixture of 60 parts of styrene and 20 parts of divinylbenzene as other monomers, and sodium dodecylbenzene sulfonate 16
And 1.5 parts of sodium persulfate were added and sufficiently stirred to obtain a mixed solution.

The obtained mixed solution was stirred and reacted at about 80 ° C. for about 5 hours while stirring at a rate of about 250 revolutions per minute. After the stirring reaction, the mixed solution was cooled to a pore size of 8 μm, 2 μm
m, 1 μm, 0.8 μm, 0.6 μm, 0.45 μm,
Suction filtration was performed using a 0.2 μm filter and a 0.1 μm filter sequentially to remove coarse powder. Next, the filtrate was ultrafiltered with about 50 liters of ion-exchanged water using an ultrafiltration apparatus equipped with a ceramic filter (manufactured by NGK Insulators, Ltd.), and finally the solid content concentration was reduced. By adjusting the concentration to 25%, an aqueous dispersion of organic fine particles Pa having an acyl group was obtained.

The organic fine particles Pa having an acyl group were substantially spherical particles, and the average particle diameter was about 0.068 μm. The average particle diameter is determined by observing and photographing a dried particle obtained by freeze-drying a part of the dispersion liquid with a transmission electron microscope (TEM), and measuring an arbitrary 500 particle diameters from the photograph. , The average value calculated from the measured values.

[0146]

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<Production of Fine Particles Having No Acyl Group on Surface> (Synthesis of Inorganic Fine Particles Sp) The compound having a reactive group into which an acyl group was introduced, which was used in the synthesis of the inorganic fine particles having an acyl group, was used. A compound having a reactive group into which an n-propyl group has been introduced, that is, 62.4 parts (0.38) of the following n-propyltrimethoxysilane (manufactured by Gerest).
mol), inorganic fine particles Sp having an n-propyl group on the surface were obtained in the same manner as in the case of the inorganic fine particles having an acyl group.

[0148]

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(Synthesis of Organic Fine Particles Ps) Instead of all the compounds used in the synthesis of the organic fine particles Pa having an acyl group, a mixture of 80 parts of styrene and 20 parts of divinylbenzene was used as a monomer, and dodecylbenzene was used. 16 parts of sodium sulfonate, 1.5 parts of sodium persulfate,
And the reaction temperature was set to 70 ° C. and the reaction time was set to 5 hours.
In the same manner as in the above case, an aqueous dispersion of the organic fine particles Ps was obtained. The obtained organic fine particles P-s are substantially spherical particles,
The average particle diameter measured in the same manner as in the case of the organic fine particles Pa was about 0.067 μm.

<Synthesis of Binder Resin> (Synthesis of Polyester Resin PES-a) 99.7 parts (0.60 mol) of terephthalic acid was placed in a reaction vessel equipped with a stirrer, a thermometer, a cooling pipe, and a nitrogen gas introduction pipe. ), 66.5 parts (0.39 mol) of isophthalic acid, 211.3 parts (0.65 mol) of a 2 mol bisphenol A ethylene oxide adduct, and 24.2 parts of ethylene glycol.
Parts (0.39 mol) and 2.0 parts (0.008 mol) of dibutyltin oxide as a catalyst were added to obtain a mixed solution. After the inside of the reaction vessel was replaced with dry nitrogen gas, the obtained mixed solution was washed with nitrogen gas stream for about 200 hours.
The mixture was stirred and reacted at about 5 ° C. for about 5 hours. The temperature was further raised to about 240 ° C., and the mixture was stirred and reacted for about 3 hours. After the stirring reaction, the pressure inside the reaction vessel was reduced to 10.0 mmHg, and about 0.2 mmH under reduced pressure.
The mixture was stirred and reacted for an hour to obtain a colorless and transparent amorphous polyester resin PES-a. Each physical property of PES-a is as shown in Table 1 below.

(Synthesis of Polyester Resin PES-b) 99.7 parts (0.60 mol) of terephthalic acid was placed in a reaction vessel equipped with a stirrer, thermometer, cooling pipe, and nitrogen gas introduction pipe.
And 66.5 parts (0.39 mol) of isophthalic acid,
Bisphenol A ethylene oxide 2 mol adduct
46.3 parts (0.45 mol) and 2,2-diethyl-
19.83 parts of 1,3-propanediol (0.15 m
ol) and 27.9 parts (0.45 parts) of ethylene glycol.
mol) and 2.2 parts (0.009 mol) of dibutyltin oxide as a catalyst were added to obtain a mixed solution. After the inside of the reaction vessel was replaced with dry nitrogen gas, the mixed solution was stirred and reacted at about 190 ° C. for about 6 hours under a nitrogen gas stream, and the temperature was further raised to about 240 ° C. to perform stirring reaction for about 3 hours. After the stirring reaction, the inside of the reaction vessel is 10.0 mmHg.
The reaction was stirred under reduced pressure for about 0.2 hours to obtain a colorless and transparent amorphous polyester resin PES-b.
Each physical property of PES-b is as shown in Table 1 below.

(Synthesis of Polyester Resin PES-c) 99.7 parts (0.60 mol) of terephthalic acid was placed in a reaction vessel equipped with a stirrer, thermometer, cooling pipe and nitrogen gas inlet pipe.
And 66.5 parts (0.39 mol) of isophthalic acid,
Bisphenol A ethylene oxide 2 mol adduct
46.3 parts (0.45 mol) and 237.7 parts (0.4 mol) of bisphenol A propylene oxide 2 mol adduct.
69 mol), 19.83 parts (0.15 mol) of 2,2-diethyl-1,3-propanediol, and 2.0 parts (0.006 mol) of a titanium (IV) tetrabutoxide monomer as a catalyst. Was added to obtain a mixed solution. After the inside of the reaction vessel was replaced with dry nitrogen gas, the mixed solution was stirred and reacted at about 180 ° C. for about 5 hours under a nitrogen gas stream, and further heated to about 200 ° C. for about 1 hour for stirring reaction. After the stirring reaction, the mixed solution is mixed under a nitrogen gas stream for 1 hour.
The temperature was lowered to 20 ° C., and silica thin-layer chromatography using ethyl acetate and n-hexane as a developing solvent (hereinafter referred to as “silica thin-layer chromatography”).
Sometimes referred to as "TLC". ) Was used to confirm that no unreacted bisphenol A ethylene oxide 2 mol adduct remained.

Thereafter, ethylene glycol 1 was added to the mixed solution.
24.0 parts (2.00 mol) and 1.0 part (0.0%) of titanium (IV) tetrabutoxide monomer as a catalyst.
And the mixed solution was stirred and reacted at about 180 ° C. for about 3 hours under a nitrogen gas stream, and further heated to about 200 ° C. for about 1 hour. After the stirring reaction, the mixed solution was lowered to 120 ° C. under a nitrogen gas stream, and TL using ethyl acetate and n-hexane as a developing solvent was used.
Using C, it was confirmed that no unreacted acid components remained.

Finally, the pressure inside the reaction vessel was reduced to 0.8 mmHg, and while removing excess monomer from the mixed solution, 1
The temperature was raised to 240 ° C. at a temperature rising rate of 0 ° C./5 min, and the mixture was stirred and reacted for about 2.5 hours to obtain a pale yellow transparent amorphous polyester resin PES-c. Each physical property of PES-c is as shown in Table 1 below.

(Synthesis of Polyester Resin PES-d) In place of the compound used in the polyester resin PES-a, 108.0 parts (0.65 mol) of terephthalic acid were added.
71.9 parts of dodecenyl succinic anhydride (0.27 mo
1) and 15.4 parts of trimellitic anhydride (0.08 m
ol), 97.5 parts (0.30 mol) of bisphenol A ethylene oxide 2 mol adduct and 97.5 parts (0. 0 mol) of bisphenol A ethylene oxide 2 mol adduct.
30 mol), 1.86 parts (0.03 mol) of ethylene glycol, and 2.0 parts (0.008 mol) of dibutyltin oxide as a catalyst. The reaction temperature was 190 ° C., and the reaction time was 6 hours. Other than the above, in the same manner as in the case of the polyester resin PES-a, a pale yellow transparent amorphous polyester resin PES-d
I got Each physical property of PES-d is as shown in Table 1 below.

(Synthesis of Polyester Resin PES-e) 70 parts of the polyester resin PES-b obtained above,
Polyester resin PES-c (30 parts) was melt-kneaded with a Banbury kneader to obtain a polyester resin PES-e. Each physical property of PES-e is as shown in Table 1 below.

(Styrene-acrylic copolymer resin STA-
Synthesis of f) In a reaction vessel in which the inside of the vessel was replaced with dry nitrogen gas, THF, from which water had been sufficiently removed, was used as a solvent.
Parts and 277.7 parts of styrene as a monomer (2.
67 mol), 73.0 parts (0.57 mol) of n-butyl acrylate, and 3.8 parts (0.023 mol) of 2,2′-azobisisobutyronitrile are added and mixed, and the mixed solution is mixed. The temperature was raised to about 60 ° C., and the mixture was stirred and reacted for about 60 hours. After completion of the reaction, the mixed solution was slowly dropped into about 7000 parts of methanol while stirring to obtain a precipitate. The precipitate is filtered and dried under vacuum at about 40 ° C. to obtain a colorless and transparent amorphous styrene-acrylic copolymer resin ST.
A-f was obtained. Each physical property of STA-f is as shown in Table 1 below.

[0158]

[Table 1]

<Manufacture of Resin Dispersion as Pretreatment for Dispersion> (Manufacture of Resin Dispersion of Melt-Flushed Fine Particles) 70 parts of a binder resin and 120 parts of an aqueous dispersion of organic fine particles were mixed in a volume of 3 parts. The mixture was melted and kneaded with a liter pressure kneader to remove water, thereby obtaining a resin dispersion of fine particles having a fine particle content of 30% and subjected to melt flushing. The procedure of the melt flushing process is as follows.

First, 50 parts of a binder resin and 50 parts of an aqueous dispersion of organic fine particles were added to a kneader.
By rotating, the temperature was gradually increased and heated to 105 ° C. 10
The mixture was melted and kneaded at 5 ° C. for about 45 minutes to remove water. Next, after lowering the kneader temperature to 90 ° C.,
And 40 parts of an aqueous dispersion of organic fine particles were added, and the mixture was gradually heated to 105 ° C. again and melt-kneaded for about 30 minutes. Further, 10 parts of a binder resin and 40 parts of an aqueous dispersion of organic fine particles were added and melted and kneaded in the same manner. In addition, 120 ° C
For about 10 minutes. After cooling, it was taken out of the kneader, coarsely crushed to about several millimeters, and melt-kneaded at 120 rpm for about 10 minutes using a Banbury kneader to obtain a resin dispersion of fine particles subjected to a melt flushing treatment. A resin dispersion of these fine particles was prepared with a side of about 0.5 c.
m, and one of the fractured surfaces was observed with a scanning electron microscope (SEM) according to a conventional method. As a result, the particles were very uniformly dispersed in the resin, and an aggregate of fine particles was observed. Did not.

The combinations of the binder resin and the aqueous dispersion of organic fine particles used in Examples and Comparative Examples are shown in Tables 2 and 3 below as the composition of the toner. In Tables 2 and 3, the melt flushing treatment is indicated as "MFB".

(Production of Resin Dispersion of Fine Particles Coated with Resin) A binder resin of 1000 g was added to THF 20,000 ml.
To give a resin solution. Inorganic fine particles were added and dispersed in the resin solution, and stirred for 1 hour. After stirring, THF was evaporated at 45 ° C. under reduced pressure to obtain a dried inorganic fine particle coated with a binder resin. The dried product was pulverized with a mill to obtain a resin dispersion of fine particles subjected to a resin coating treatment.
The combinations of the binder resin and the inorganic fine particles used in Examples and Comparative Examples are shown in Tables 2 and 3 as the composition of the toner.
In Tables 2 and 3, the resin coating treatment is indicated as “PCS”.

(Production of Resin Dispersion of Fine Particles Directly Blended) A binder resin and inorganic or organic fine particles which were dried to remove water and then pulverized by a mill were mixed at a weight ratio of resin: fine particles = 7: 3, and using a small twin screw extruder (manufactured by Toyo Seiki Seisaku-sho, Ltd.), 90-150
The mixture was heated, melted and kneaded once at a temperature of ° C to obtain a resin dispersion of fine particles subjected to a direct blending treatment. Combinations of a binder resin and an aqueous dispersion of organic fine particles used in Examples and Comparative Examples are shown in Tables 2 and 3 as toner compositions. In Tables 2 and 3, the direct blending process is indicated as “DB”.

(Examples 1 to 10) According to the composition shown in Table 2, a binder resin, a resin dispersion of fine particles, and a flushed cyan pigment (Cyanine Blue 4933M, manufactured by Dainichi Seika Kogyo Co., Ltd.) The resin dispersion (pigment content: 30% by weight) and, if necessary, wax were melted and kneaded at 120 revolutions per minute for about 15 minutes using a BR-type Banbury kneader (manufactured by Kobe Steel). The kneaded material is formed into a plate having a thickness of about 1 cm by a rolling roll, roughly pulverized to about several millimeters by a Fitz mill type pulverizer, finely pulverized by an IDS type pulverizer, and sequentially classified by an elbow type classifier. A cyan toner having a pigment content of 4%, a volume average particle diameter d ⁵⁰ = 6.9 μm, and a fine particle content in the toner as shown in Table 2 was prepared. Incidentally, the volume average particle diameter d ^{50 of} the obtained cyan toner is as follows.
Was measured with a Coulter counter TA-II (manufactured by Coulter). Here, the volume average particle diameter d ⁵⁰ is 5 of the total volume integrated from the large particle side of the Coulter counter.
The volume average particle diameter account for 0% point to (d ^50). to this,
Using a Henschel mixer, add hydrophobic silica powder R97
2 (manufactured by Nippon Aerosil Co., Ltd.) by external addition and mixing by 3%, and a cyan color toner for electrophotography (1) to (1) of the present invention.
0) was obtained.

(Comparative Examples 1, 6 to 9) Cyan electrophotography was performed in the same manner as in Example 1 and the like, according to the composition shown in Table 3, except that the resin dispersion of fine particles used in Example was not used. Color toners (11) and (16) to (19) were obtained.

(Comparative Examples 2 to 5) According to the composition shown in Table 3,
In the same manner as in Example 1, cyan color toners (12) to (15) for electrophotography were obtained.

<Evaluation 1> Regarding the obtained electrophotographic color toners (1) to (10) and electrophotographic color toners (11) to (19), the dispersion state of fine particles and the toner The elastic properties were evaluated. The evaluation method is as follows. The results are shown in Tables 4 to 6 below.

(Dispersion state of fine particles) For each of the obtained color toners for electrophotography, after embedding in a two-part type epoxy-based embedding agent, cooling with liquid nitrogen, and using a microtome equipped with a diamond knife, the thickness was reduced. Make ultra-thin sections of 80 μm,
It was observed and photographed with a scanning electron microscope (FE-SEM). The photograph was taken at a magnification of 30,000 times for 50 randomly extracted toners. From the photograph, the number of toners containing aggregates having a maximum length of 1.0 μm or more was counted, and the dispersion state of the fine particles was evaluated according to the following criteria. [Evaluation Criteria] A: Very good dispersion state. ：: Good dispersion state. ×: Not sufficiently dispersed. Tables 4 and 5 also show the number of toner particles containing aggregates having a particle diameter of 1.0 μm or more, which are present in 50 toner particles.

(Measurement of Viscoelastic Properties of Toner) The viscoelastic properties of the color toner for electrophotography were measured as follows. That is, a rheometer (RDA2
(RHIOS system Ver.4.3), manufactured by Rheometrics Co., Ltd.).
A 1 rad, 25 mm diameter cone & plate was used.
First, about 0.5 g of the toner was melted on a hot plate heated to 140 ° C. using a spatula or the like and molded into a diameter of about 25 mm to prepare a measurement sample. This operation was performed in about 90 to 120 seconds. Next, stabilize the rheometer at a temperature at which rheology can be measured, and after one minute after setting the temperature at 20 ° C. higher than the measurement temperature, place the obtained measurement sample near the center of the plate and lower with a spatula or the like. Pressed against the side plate. Then, while changing the set temperature of the rheometer to the measurement temperature, taking care not to allow air to enter between the plate and the measurement sample, while gradually lowering the upper cone plate and applying pressure to the measurement sample, With the plate gap set to 0.05 mm, the measurement sample protruding from the plate was removed, and adjustment was made so that no step was formed between the plate and the wall surface of the measurement sample. Finally, the measurement sample was left for 15 minutes to stabilize the temperature. This series of operations must be performed within 40 minutes from the start of setting until the temperature is stabilized. After the temperature was stabilized, the following measurement 1 and measurement 2 were continuously performed in this order.

(Measurement 1) Dynamic complex elastic modulus G ^{* of} color toner for electrophotography (distortion rate = 100%, frequency = 10 rad)
d / sec). Measurement frequency is 10 rad / sec
, And the strain rate is changed from 1.0 to 100.0%,
The strain rate dependency was measured at 10 measurement points (the number of measurement points per digit was 5), and the dynamic complex elastic modulus G ^{* of} each electrophotographic color toner (strain rate = 100%, frequency = 10 rad / se).
c) was determined.

(Measurement 2) Dynamic of Color Toner for Electrophotography
Complex modulus G^*(Distortion rate = 10%) frequency dependence (G^*
(100 rad / sec) / G^*(1 rad / sec))
Measurement. The measurement distortion rate is fixed at 10%, and the frequency is 0.1 to
Change to 400 rad / sec and measure 20 points (1 digit
The number of measurement points during the measurement was 5) and the frequency dependence was measured.
Dynamic complex elastic modulus G of true color toner^*(Distortion rate = 10
%) (G ^*(100 rad / sec) / G
^*(1 rad / sec)). In Tables 4-6, frequency
Dependency (G^*(100 rad / sec) / G^*(1 rad /
sec)) is "G^*(100) / G^*(1) ".

The above Measurements 1 and 2 were performed by measuring the dynamic complex elastic modulus G of the binder resin used in each color toner for electrophotography.
^* (Distortion rate = 100%, frequency = 10 rad / sec)
Was performed at a temperature of 1,000 Pa. The temperature was determined by using the binder resin used in each color toner for electrophotography and changing the temperature in Measurement 1 described above. Also,
Tables 4 to 6 also show tan δ measured at a temperature at which the dynamic complex elastic modulus G ^* (strain rate = 100%, frequency = 10 rad / sec) of the binder resin is 1000 Pa.

<Evaluation 2> The obtained color toners for electrophotography (1) to (8) and color toners for electrophotography (11) to (17) of the present invention were used, and an image was output for each (image output 1). ), Fixation by supply of minute oil (fixing method 1) to form a fixed image, and fixation characteristics, glossiness, color development,
The hot offset, the releasability of minute oil supply fixation, the heat preservability of the toner, and the heat preservability of the image were evaluated. Each evaluation method is described below. The evaluation results are shown in Tables 4 and 5 below.

(Image Output 1) Electrophotographic Color Toner 8
Parts and 100 parts of a carrier were mixed to prepare electrophotographic developers (1) to (8) and (11) to (17). The carrier was a resin-coated carrier, and a carrier in which a ferrite core was coated with a mixture of an amino group-containing vinyl polymer and a fluoroalkyl group-containing vinyl polymer was used. In the electrophotographic developers (1) to (8), the electrophotographic color toners (1) to (8) of the present invention obtained above are used so that the numbers correspond to each other.
In the electrophotographic developers (11) to (17), the electrophotographic color toner (1
1) to (17) were used.

For each of the prepared electrophotographic developers, a color copying machine “A color” from which a fixing device was removed was used.
935 "(manufactured by Fuji Xerox Co., Ltd.) to output an unfixed image. Output image is 50mm ×
For a solid image of 50 mm size, the image toner amount is 1c
0.65 mg per m ² . The paper is “L paper”
(Manufactured by Fuji Xerox Office Supply Co., Ltd.). “L paper” has been conventionally used in black-and-white copying machines in large numbers.

(Fixing Method 1) The fixing is performed by using a color copier “A”.
The fixing device removed from "color 935" (manufactured by Fuji Xerox Co., Ltd.) was used after being modified so that the roll temperature of the fixing device could be changed. The paper transport speed of the fuser is
It was 160 mm per second. The fixing device includes A colo
Care was taken to prevent offset from occurring when the fuser oil for r (silicone oil) was applied. The oil was applied by attaching an oil-impregnated roll to a heat roll, and the amount of oil applied was controlled by a blade. The application amount is 2.0 mg (5.1 × 10
^-3 mg / cm ² ). The amount of silicone oil applied was measured by passing white paper through a fuser, extracting the oil with the oil adhering to the white paper with a Soxhlet extractor using hexane as a solvent, and measuring the oil amount with an atomic absorption spectrometer. Quantified. Using the above fixing device, an unfixed image composed of each electrophotographic color toner is heated to a fixing device temperature of 120 ° C.
The image was fixed by appropriately changing the temperature to 200 ° C. in steps of 5 ° C. to obtain a fixed image.

(Evaluation of Fixed Image) The 15 types of fixed images obtained above were visually evaluated, and the temperature at which image deterioration (hereinafter referred to as “density unevenness”) caused by insufficient melting of toner was observed. And image quality degradation due to the penetration phenomenon (hereinafter,
This is referred to as “permeation unevenness”. ) Was determined. In terms of image quality, density unevenness is literally observed as density unevenness,
It occurs from extremely low temperatures and disappears as the fixing temperature increases. On the other hand, permeation unevenness is observed as white spots in a solid image, and occurs and worsens as the fixing temperature increases. In the image using the electrophotographic color toner (11) of Comparative Example 1, each image corresponding to the temperature at which the density unevenness disappears and the temperature at which the permeation unevenness occurs is used as a reference image, and fixing is performed using the other electrophotographic color toners. As compared with the image, the temperature at which the density unevenness disappeared or the penetration unevenness occurred was determined similarly to the reference image.

The lowest temperature at which the density unevenness disappears indicates the lowest fixing temperature, and the temperature at which the permeation unevenness occurs indicates the soaking start temperature. Further, the penetration latitude is a temperature range (t) from the penetration start temperature to the minimum fixing temperature, that is, a temperature range in which an image in which a penetration phenomenon does not occur can be obtained. The evaluation of the penetration latitude was performed according to the following criteria. [Evaluation criteria] ○: 25 ° C ≦ t △: 15 ° C <t <25 ° C ×: t ≦ 15 ° C

(Evaluation of Glossiness) The glossiness (gloss value) of the fixed image at the minimum fixing temperature was measured using a gloss meter (GM-2).
6D, manufactured by Murakami Color Research Laboratory Co., Ltd.) under conditions where the incident light angle on the image was 75 degrees.

(Evaluation of coloring property) The coloring property was evaluated according to the following criteria. [Evaluation Criteria] ：: The gloss value was 15 or more, and there was no problem in the color developability. X: The gross value was less than 15, and the lack of density was remarkably observed.

(Evaluation of Releasability of Minute Oil Supply and Fixation) In the image output 1 and the fixing method 1, a size of 50 mm ×
A solid image portion located at the leading end of an output image of 270 mm and 2.0 mg per 1 cm ^{2 of} image toner was fixed every 5 ° C., and evaluated according to the following criteria. ：: The temperature range in which the paper can be peeled without being wound around the fixing roll was 30 ° C. or more. C: The temperature range in which the paper can be peeled off without being wound around the fixing roll was 0 ° C. or more and less than 30 ° C.

(Evaluation of Thermal Storage Stability (Heat Resistance Blocking Property) of Toner) 5 g of the electrophotographic color toner was
C, left in a 50 RH% chamber for 17 hours. After the temperature was returned to room temperature, 2 g of the electrophotographic color toner was put into a mesh having a mesh size of 45 μm and vibrated under a predetermined condition. The weight of the toner remaining on the mesh was measured, and the weight ratio to the charged amount was calculated. This value was used as the heat blocking index of the toner, and evaluation was performed according to the following criteria. [Evaluation Criteria]: Heat-resistant blocking index ≦ 3% ○: 3% <heat-resistant blocking index ≦ 5% Δ: 5% <heat-resistant blocking index ≦ 10% ×: 10% <heat-resistant blocking index

(Evaluation of Thermal Preservation of Image (Fixed Image Document Offset)) The transferred image portions of the image after fixing are superimposed on each other, a load of 50 g / cm ² is applied, and a temperature of 5 is applied.
It was left in an environmental chamber at 5 ° C. and a humidity of 60% RH for 7 days, and the image offset was evaluated according to the following criteria. [Evaluation Criteria] ：: Peeling was possible without applying any force, or no image deterioration (image transfer) was observed even when peeling was performed with applying force. ：: No image deterioration (transfer of image) was observed at the time of peeling. Δ: Degradation due to image transfer occurred during peeling, but did not result in damage to the paper. ×: The image was lost during peeling, and the paper was damaged.

<Evaluation 3> Examples 9 to 10 and Comparative Examples 8 to
9, the electrophotographic color toner of the present invention (9) to
(10) and electrophotographic color toners (18) to (1)
Using 9), image output (image output 2) and oil-less fixing (fixing method 2) were performed for each of them to form a fixed image, and the releasability of oil-less fixing was evaluated. Also,
Fixing characteristics, glossiness, color developability, hot offset, heat preservability of toner, and heat preservability of image were evaluated in the same manner as in Evaluation 2 described above. The output image 2, the fixing method 2, and the method for evaluating the releasability of oilless fixing are described below. The evaluation results are shown in Table 6 below.

(Image output 2) Electrophotographic developers (9) to (10) and (18) to
(19) was prepared, and an unfixed image was output. In the electrophotographic developers (9) to (10), the electrophotographic color toners (9) to (10) of the present invention obtained above are used so that the numbers correspond to each other. In the electrophotographic developers (18) to (19), the electrophotographic color toners (18) to (19) similarly obtained above were used.

(Fixing Method 2) The fixing method was the same as that of the fixing method 1 except that the surface material of the fixing roll of the fixing device used in the fixing method 1 was changed to a fluororesin PFA tube and the amount of silicone oil applied was set to 0. In the same manner, a fixed image using each electrophotographic color toner was obtained.

(Evaluation of oil-less fixing releasability) In image output 2 and fixing method 2, the size was 50 mm × 270 m.
m, a solid image portion located at the tip of an output image of 2.0 mg per 1 cm ^{2 of} image toner amount was fixed every 5 ° C., and evaluated according to the following criteria. ：: The temperature range in which the paper can be peeled without being wound around the fixing roll was 30 ° C. or more. C: The temperature range in which the paper can be peeled off without being wound around the fixing roll was 0 ° C. or more and less than 30 ° C.

<Evaluation 4> Using the obtained color toners for electrophotography (1) to (10) and color toners for electrophotography (11) to (19) of the present invention, image output was performed for each of them (image output 3). ), Fixation with minute oil supply (fixing method 3)
To form a fixed image, and the OHP of the obtained fixed image
The light transmittance was evaluated. The image output (image output 3), fixing (fixing method 3), and evaluation method are described below.

(Image output 3) Except that the paper was changed from "L paper" to OHP for black and white (manufactured by Fuji Xerox Co., Ltd.)
An unfixed image was output in the same manner as in image output 1.
In addition to the solid image, a 50% density image was also output.

(Fixing Method 3) The electrophotographic color toners (1) to (8) of the present invention and the electrophotographic color toner (1)
In the cases of 1) to (17), the transport speed is set to 50 mm per second,
Fixing method 1 except that the fixing unit temperature was fixed at a temperature 15 ° C. higher than the minimum fixing temperature of each electrophotographic color toner.
A fixed image was obtained in the same manner as described above. In the case of the electrophotographic color toners (9) to (10) and the electrophotographic color toners (18) to (19) of the present invention, the transport speed is set to 50 / sec.
mm, and the fixing unit temperature was fixed at a temperature 15 ° C. higher than the minimum fixing temperature of each electrophotographic color toner.
A fixed image was obtained in the same manner as in fixing method 2.

(Evaluation of OHP light transmittance) The light transmittance of the obtained 19 types of fixed images was measured using a spectrophotometer (U-3210,
The measurement was performed in a mode with a wavelength of 480 nm using Hitachi, Ltd.).

[0192]

[Table 2]

[0193]

[Table 3]

[0194]

[Table 4]

[0195]

[Table 5]

[0196]

[Table 6]

(Examples 1 to 8 and Comparative Examples 1 to 7)
From the results in Tables 4 and 5, the following can be said. In the color toners for electrophotography (1) to (8) of the present invention containing fine particles having an acyl group on the surface, all of the usable temperature range from the minimum fixing temperature to 20 ° C or more (fixing temperature range;
It has the latitude temperature range [° C.] in Table 4, and has a sufficient usable temperature range even when using paper with low paper density and surface smoothness. In addition, both gross values are 2
8 or more, and both the glossiness and the coloring property of the image with each electrophotographic color toner were sufficient. In addition, it is excellent in all aspects of penetration latitude, color development, hot offset, releasability of fine oil supply fixing, toner heat preservation, and image heat preservation, and it is sufficient for practical use overall The toner performance was shown. Further, the transmittance of the OHP light was 80% or more in all cases, which was practically sufficient. Even in an image having an image density of 50%, the light transmittance was 75% or more. The color development of the OHP transmission image was also clear and excellent. Above all, in the electrophotographic color toner (7) of the present invention, two kinds of fine particles having an acyl group on the surface were used, and particularly excellent toner heat preservability was exhibited.

On the other hand, the electrophotographic color toner (11) obtained in Comparative Example 1 was a cyan toner conventionally used in a color copying machine, and did not use fine particles having an acyl group on the surface. To obtain a sufficient usable temperature range (fixing temperature range; latitude temperature range [° C. in Table 5]) when the temperature rises by 15 ° C. from the temperature at which melting unevenness disappears due to the sharp melt property. Could not. Therefore, in this embodiment, since “L paper (manufactured by Fuji Xerox Office Supply Co., Ltd.)” is used, the temperature at which the toner permeation phenomenon can occur despite having a latitude temperature range (usable temperature range) of 15 ° C. As described, since the lower the paper density and the lower the smoothness of the paper surface, the more the paper is likely to occur, a paper called a thin paper having a low paper density (for example, “S paper (manufactured by Fuji Xerox Office Supply)”) Recycled paper containing waste paper with poor paper surface smoothness (for example, “WR paper (manufactured by Fuji Xerox Office Supply)”, “Green 100 paper”)
, Etc.), the usable temperature range becomes narrower and may be lost in some cases.

The electrophotographic color toner (16) obtained in Comparative Example 6 was the same as the electrophotographic color toner (1).
Although a binder resin having a higher molecular weight than that in 1) was used,
An effective usable temperature range was not obtained, resulting in an increase in the minimum fixing temperature. Although the electrophotographic color toners (12) and (14) obtained in Comparative Examples 2 and 4 contain fine particles having an acyl group on the surface, the fine particles are not in a well-dispersed state, and the viscoelasticity defined in the present invention. Since the characteristic (G ^* ) was not satisfied, a sufficient usable temperature range was not obtained as a result. Also, in the electrophotographic color toners (13) and (15) obtained in Comparative Examples 3 and 5, fine particles are well dispersed and exist. The viscoelastic properties (G ^* ) specified in the invention were not satisfied, and a sufficient usable temperature range could not be secured.

(Examples 9 to 10 and Comparative Examples 8 to 9) From the results in Table 6, the following can be said. That is,
Even in a system in which fixing is performed under oil-less conditions, in the electrophotographic color toners (9) and (10) of the present invention using fine particles having an acyl group on the surface, the use of the toner at a minimum fixing temperature of 20 ° C. or higher is required. It has a feasible temperature range (fixing temperature range; latitude temperature range [° C.] in Table 6), and also has a penetration latitude, a color development property, a hot offset, a releasability of fixing by supplying a small amount of oil, and a heat preservation property of the toner. It was excellent in all of the heat preservability of the image, and showed a sufficient toner performance in practical use overall. The transmittance of the OHP light was 80% or more, which was sufficient for practical use, and the light transmittance was 75% or more even in an image having an image density of 50%. The color development of the OHP transmission image was also clear and good. Among them, the electrophotographic color toner (10) of the present invention exhibited particularly excellent toner heat preservability because two kinds of fine particles having an acyl group on the surface were used.

In the electrophotographic color toner (18) obtained in Comparative Example 8, good releasability was obtained, but the same binding as the electrophotographic color toners (9) to (10) of the present invention was performed. Even when a resin is used, the minimum fixing temperature is high, the heat preservability of the toner and the heat preservability of the image are poor, and the resin cannot be put to practical use. In the electrophotographic color toner (9) obtained in Comparative Example 9, the viscoelastic properties (G ^* ) of the binder resin did not show oilless suitability, and the toner thickness of a single color (0.45 mg / cm) was not obtained. ^Although the image of ² ) could be peeled off, the image of the full-color toner thickness (1.4 mg / cm ² ) could not be peeled off and could not withstand practical use.

<Evaluation 5> The cyan pigment used in Example 1 was replaced with a magenta pigment (Seika Fast Carmine 1476).
T-7, manufactured by Dainichi Seika Kogyo Co., Ltd.), yellow pigment (Seika First Yellow 2400, Dainichi Seika Kogyo Co., Ltd.)
Magenta, yellow and black color toners for electrophotography of the present invention in the same manner as in Example 1, except that carbon black (Carbon Black # 25, manufactured by Mitsubishi Kasei Co., Ltd.) was used in that order. I got Using the cyan full color toner for electrophotography of the present invention obtained in Example 1 and the magenta, yellow and black color toners for electrophotography of the present invention, four full-color toners were used. Output (image output 4) and fixing (fixing method 4) were performed to form a fixed image. Further, a durability test was carried out using the above four color toners for electrophotography. further,
The same was performed for the electrophotographic color toner (9) obtained in Example 9. The method of each evaluation is shown below.

(Image Output 4) An electrophotographic developer of each color was prepared using four color electrophotographic color toners and the same carrier as that used in the image output 1, and the image output 1 Similarly, an unfixed image was obtained.

(Fixing Method 4) A fixed image was obtained in the same manner as in the fixing method 1.

(Durability test) Continuous image output and fixing of 10,000 sheets were performed, and the fixed image thereafter was visually evaluated to determine whether or not any trouble occurred.
Even after the continuous image output of 10,000 sheets, no image disturbance occurred, and a good image similar to the initial image was obtained. Further, no trouble occurred in each of the electrophotographic processes of development, transfer and fixing.

<Evaluation 6> Using the electrophotographic color toner (4) of the present invention obtained in Example 4, image output (image output 5) and fixing (fixing method 5) were performed to form a fixed image. ,
The fixed image was evaluated by the following method. (Image output 5) An unfixed image was obtained in the same manner as in image output 1.

(Fixing Method 5) An image forming apparatus provided with a thermal transfer type belt fixing device and having the same structure as in FIG. 4 was prepared, and a fixed image was formed.

The image obtained by the fixing method 5 had no image shift and was of high quality. According to the electrophotographic color toner of the present invention, in the toner, when fine particles having an acyl group on the surface thereof are sufficiently dispersed and a specific range of viscoelasticity is satisfied, prevention of uneven melting and reduction of paper fibers While preventing the penetration phenomenon of toner,
High image quality and high color development after fixing can be obtained.
The light transmittance was also good. In addition, the toner properties such as heat blocking properties were not problematic. Further, the fixing temperature was lowered while good oil-less peelability was obtained, and the suitability for production was good.

[0209]

According to the present invention, a wide fixing temperature range, excellent fixability at low temperatures, and suppression of toner penetration into papers other than specialty paper can be achieved without deteriorating the toner characteristics, thereby achieving high color development. An electrophotographic color toner capable of stably forming a high-quality color image can be provided. Also,
Excellent fixability at low temperatures, and prevents deterioration of the image quality of toner images due to toner penetration even on paper other than special paper,
An electrophotographic developer capable of stably forming a high-color, high-quality color image can be provided. Further, according to the image forming method of the present invention, it is possible to stably form a color image with high color development and high image quality.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a dynamic complex elastic modulus G ^{* of a} toner and a temperature.

FIG. 2 is a schematic configuration diagram illustrating an example of an image forming apparatus suitable for the image forming method of the present invention.

FIG. 3 is a schematic configuration diagram illustrating an example of an image forming apparatus suitable for the image forming method of the present invention.

FIG. 4 is a schematic configuration diagram illustrating an example of an image forming apparatus suitable for the image forming method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Toner image 11, 31 Photoconductor 12, 32 Cleaner 13, 33 Charger 14, 34 Exposure device 15a-15d, 35 Developing device 16, 23, 36 Transfer charger 17 Transfer roll 18 Peeling nail 19 Heating roller 20 Pressure Rollers 21, 43 Transferred body 22 Roll-shaped intermediate transfer body 37a-37d Developing unit 38 Belt-shaped intermediate transfer body 39 Heating element 40 Heating support roll 41 Support roll 42 Pressure roll

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masaki Nakamura 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Satoshi Yoshida 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. Reference) 2H005 AA01 AA06 AA08 AA21 CA21 CA26 EA10 FB01

Claims (3)

[Claims] At least a binder resin, a colorant and a light color
Or electrophotography containing toner particles consisting of colorless fine particles
In the color toner for use, the fine particles are represented on the surface by the following general formula (I).
A dynamic complex elastic modulus G of the binder resin having an acyl group;
^*(Distortion rate = 100%, frequency = 10 rad / sec)
Is measured at a temperature at which the
Complex modulus G ^*(Distortion rate = 100%, frequency = 10r
ad / sec) is 3000 to 50,000 Pa
And a color toner for electrophotography. Embedded image[Wherein, R represents an aliphatic group consisting of a carbon atom and a hydrogen atom.
Hydrocarbon, alicyclic and aromatic hydrocarbon groups
Represents a monovalent substituent selected. ] 2. An electrophotographic developer comprising at least the electrophotographic color toner according to claim 1. Forming a latent image on a latent image holding member;
Developing the latent image with an electrophotographic developer to form a toner image, transferring the toner image onto a transfer target, and fixing the toner image transferred onto the transfer target, In the image forming method, the electrophotographic developer is the electrophotographic developer according to claim 2, and in the step of fixing the toner image,
An image forming method using a heating contact-type fixing device.