JPH11338182A - Toner and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner which does not cause defects on a fixing member without decreasing the fluidity or electrification characteristics in a durable properties. SOLUTION: The toner contains toner particles containing at least a binder resin and a coloring agent, and two kinds of inorg. fine particles A and B having different number average particle sizes. The toner particles have weight average particle size of 2 to 8 μm, and average circularity of 0.955 to 0.998. The inorg. fine particles A are hydrophobic silica fine particles having >=30 nm and <100 nm number average particle size. The inorg. fine particles B are hydrophobic titanium oxide fine particles of a rutile crystalline structure having >=100 nm and <500 nm number average particle size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used in a copying machine, a laser printer, and the like, and to an image forming method using the toner.

[0002]

2. Description of the Related Art In general, in electrophotography, an electrostatic latent image is formed on the surface of an electrostatic image carrier having a photosensitive layer made of a photoconductive material, and this latent image is charged to a positive electrode or a negative electrode. A visible image is formed by developing with the developer thus obtained.

In the developing step, the developer is once adhered to an electrostatic image holder such as a photosensitive member on which an electrostatic image is formed, and then is transferred from the electrostatic image holder to paper or the like in a transfer step. After being transferred to the transfer material, it is fixed on the transfer material in a fixing step. At this time, as a developer for developing the electrostatic latent image formed on the electrostatic image holding surface, a two-component developer composed of a carrier and a toner and a one-component developer not requiring a carrier ( Magnetic toners and non-magnetic toners) are known. In the two-component system, the toner is charged mainly by friction between the carrier and the toner, and in the one-component system, the toner is charged mainly by friction between the toners.

A method for controlling the shape of toner particles for the purpose of improving the flow characteristics, charging characteristics, transferability, etc. of the toner irrespective of the difference between the two-component developer and the one-component developer. Have been proposed and are widely known. On the other hand, regardless of the difference between the two-component developer and the one-component developer, for the purpose of seeking higher reproducibility and higher definition of the fixed image, or for the purpose of reducing the energy consumption required for fixing the toner image. A method for reducing the size of toner particles has been proposed and is widely known. Further, for the purpose of reducing the time and energy consumption required for fixing the toner image, a method of lowering the softening point temperature of the binder resin in the toner and a method of increasing the fixing pressure in the fixing member have been proposed, respectively. Widely used. Further, as a method of not increasing the energy consumption while increasing the printing speed, in addition to the various methods described above, the toner particles are made spherical, and the number of contact points between the toner particles in the toner layer in the toner image before fixing is increased. Thus, a method for improving heat conductivity has been proposed and used.

[0005] Regarding the developer, irrespective of the difference between a two-component developer and a one-component developer, toner particles and various metal oxides are used for the purpose of improving the flow characteristics and charging characteristics of the toner. A method of mixing and using inorganic fine particles has been proposed and widely used. Also, in order to meet the need to provide images of the same quality even in different environments, methods for modifying the hydrophobicity, charging characteristics, etc. of the surface of the inorganic fine particles are widely known, and specific silane coupling agents, titanates A method of treating with a coupling agent, a silicone oil, a fatty acid or the like, a method of coating with a specific resin, and the like have been proposed. Various inorganic oxides as the inorganic fine particles,
Nitride, boride and the like are preferably used. For example, silica, alumina, titania, zirconia, barium titanate, aluminum titanate, strontium titanate,
Magnesium titanate, cerium oxide, zinc oxide, chromium oxide, cerium oxide, antimony oxide, tungsten oxide, tin oxide, tellurium oxide, manganese oxide, boron oxide, silicon carbide, boron carbide, titanium carbide, silicon nitride, titanium nitride, nitride Boron and the like.

However, these fine particles are not necessarily satisfactory in performance such as fluidity imparting effect and charge imparting effect to the toner depending on the particle diameter.

To solve the above problems, a method has been proposed in which a plurality of fine particles having different particle diameters are added to simultaneously obtain a plurality of effects.
No. 6,153, a method of adding two different kinds of inorganic fine particles; use of two kinds of silica having different average particle diameters as described in JP-A-6-95425 and JP-A-7-261446. Method: JP-A-6-167827
JP-A-63-28955, a method using two kinds of fine particles having different average particle diameters and types as disclosed in
A method using three types of inorganic fine particles having different average particle diameters as disclosed in Japanese Patent Application Laid-Open No. 9-209 is widely known.

As a means for improving the flow characteristics and charging characteristics of the toner, a method of mixing fine resin particles is widely known. However, in general, it is difficult to easily achieve optimal flow characteristics, charging characteristics, hydrophobicity, and the like by using only resin fine particles, and these resin fine particles are often used as an auxiliary for the inorganic fine particles.

[0009]

As described above, high reproducibility,
In order to achieve high-definition images and high-speed printing, and not to impair the flow characteristics and charging characteristics of the toner, the above-mentioned conventionally known techniques have been used alone or in combination. However, the present inventors have tried to obtain the same image continuously by using toner obtained by a combination of these known techniques. It was found that there was a portion where the fixing power was uneven. That is, when the surface of the fixed image portion on the recording material was rubbed with a certain stress, it became clear that there was a portion where the toner particles remarkably separated from the recording material.

As a result of intensive studies, the present inventors have found that the fixing defects are caused by minute defects in the fixing member itself. It has also been found that the fine defects are caused by inorganic fine particles used as an external additive in the toner damaging the fixing member due to repeated fixing.

Accordingly, an object of the present invention is to achieve high reproducibility, high definition, and high-speed printing, and to fix the toner without changing the fluidity of the toner even when an image is continuously formed for a long period of time. An object of the present invention is to provide a toner and an image forming method in which abrasion resistance of an image is constant.

It is another object of the present invention to provide a toner and an image forming method which can reduce the energy consumption of an image forming apparatus while maintaining high reproducibility and high definition even when an image is continuously formed for a long period of time. Is to provide.

[0013]

According to the present invention, there is provided a toner having at least a binder resin and a colorant, and two kinds of inorganic fine particles A and B having different number average particle diameters. The weight average particle diameter of the particles is 2 to 8 μ
m, the average circularity is 0.955 to 0.998, the inorganic fine particles A are hydrophobic silica fine particles having a number average particle size of 30 nm or more and less than 100 nm, and the inorganic fine particles B are The present invention relates to a toner characterized by being hydrophobic titanium oxide fine particles having a rutile type crystal structure having a particle size of 100 nm or more and less than 500 nm.

Further, according to the present invention, the surface of the electrostatic image holder is charged, an electrostatic latent image is formed on the charged surface of the electrostatic image holder, and the electrostatic latent image is developed with toner. In the image forming method of forming an image, transferring the toner image to a recording material with or without an intermediate transfer member, and fixing the toner image to the recording material, the toner having the above-described configuration is used as the toner. And an image forming method.

The inventors of the present invention have conducted intensive studies on the relationship between the material used for the toner, the associated physical properties, and the image. As a result, the shape of the toner particles is determined, and a plurality of certain materials are combined and added as a toner component. As a result, it has been found that a toner can be obtained which does not impair the fluidity and charging characteristics and does not cause minute defects on the fixing member even when the image is continuously formed for a long period of time.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The toner particles have a weight average particle size of 2 to 2.
8 μm and the average circularity of the particles is 0.955 to
0.998, and the number average particle diameter of the inorganic fine particles A is 30.
nm or more and less than 100 nm, and the fine particles are hydrophobic silica, and the number average particle diameter of the inorganic fine particles B is 100 n.
The reason why the above-mentioned object is achieved by using a toner having a particle size of at least m and less than 500 nm and the fine particles being a hydrophobic titanium oxide having a rutile-type crystal structure is unknown in detail, It is inferred as follows.

In order to provide a stable image for a long period of time, it is necessary to use inorganic fine particles having a size which does not hinder the flowability of the toner particles and which will not be fixedly buried on the surface of the toner particles even after long-term use. It must be added as an enhancer. In selecting the inorganic fine particles, it is necessary to sufficiently consider the particle size and shape of the toner particles, and the weight average particle size is 2 to achieve high reproducibility, high definition, and high-speed printing as in the present invention. When toner particles having a particle diameter of 8 μm and an average circularity of 0.955 to 0.998 are used, the number average particle diameter is 30 nm to 100 n.
The present inventors have found that it is most preferable to use inorganic fine particles having a particle diameter of less than m. However, it was also clarified that the use of the inorganic fine particles not subjected to the surface treatment damaged the fixing member due to the repeated fixing.

Here, when the surface of the inorganic fine particles is treated with silicone oil, the surface slipperiness of the inorganic fine particles is improved, so that it is possible to prevent minute defects in the fixing member.

On the other hand, the number average particle size is 30 nm or more and 1
When the surface of the inorganic fine particles having a particle diameter of less than 00 nm is treated with silicone oil, the charging characteristics thereof change, so that the electrostatic adhesion to the fixing member increases as compared with the untreated inorganic fine particles. As a result, the amount of the fine particles A that are released from the toner surface and electrostatically adhere to the fixing member surface increases. This does not immediately cause a fine defect in the fixing member, but if the fixing process is continued for a very long time, a sufficient amount of heat enough to fix the toner particles is continuously applied. Since these particles cannot be applied and cause fixing failure, it is necessary to remove these fine particles A effectively.

The number average particle diameter is 100 nm or more and 500 nm
Inorganic fine particles B treated with less than silicone oil,
Since the surface is treated with silicone oil, the fine particles A are removed without damaging the fixing member, and since the particle diameter is larger than A and the electrostatic adhesion is different from A, the fine particles A adhere to and remain on the fixing member. It is considered that the fixing member is not damaged. However, when the number average particle size is 100
When the inorganic fine particles B treated with a silicone oil having a thickness of at least 500 nm and less than 500 nm are used alone, there is no small defect in the fixing member, but there is a portion in the initial image sample where the fixing power of the image after fixing is already weak. I found out. This is presumably because the number average particle diameter of the inorganic fine particles B is larger than that of A and a larger amount of heat is taken out during fixing, so that a fixing defect occurs due to a failure to supply sufficient heat to sufficiently fix the toner particles. Is done.

In the present invention, the weight average particle size of the toner particles is 2 to 8 μm. When the weight average particle diameter of the toner particles is less than 2 μm, it becomes difficult to uniformly charge the toner particles, and an unclear image with a lot of fogging and scattering on a non-image portion is obtained. When the weight average particle size of the toner particles exceeds 8 μm, characters or line images are liable to be scattered, resulting in an image having poor definition.

In the present invention, the average circularity of the toner particles is in the range of 0.955 to 0.998. Here, the average circularity is determined by a flow-type particle image analyzer, and is determined by the arithmetic mean of the circularities calculated by the following equation.

[0023]

(Equation 1)

When the average circularity of the toner particles is less than 0.955, the charged portions on the surface of the toner particles are unevenly distributed, so that the inorganic fine particles A are easily released from the surface of the toner particles in a fixing step of long-term continuous printing. This causes deterioration of the fixing member. On the other hand, when the average circularity exceeds 0.998, frictional electrification between toners becomes difficult, and an unclear image with a lot of fogging and scattering on non-image portions is obtained.

As a means for adjusting the average particle diameter and sphericity of the toner particles, conventionally known methods can be used.

For example, there are a conventional hot-water bath method in which toner particles are dispersed in water and heated, a heat treatment method in which the toner particles are passed through a hot air stream, and a mechanical impact method in which mechanical energy is applied for treatment. Alternatively, JP-A-36-10231, JP-A-59-53856, and JP-A-59-6.
No. 1842, a method of directly producing toner particles using a suspension polymerization method, or a method of directly polymerizing an aqueous organic solvent using an aqueous organic solvent which dissolves the monomer but does not dissolve the obtained polymer. And a emulsion polymerization method typified by a soap-free polymerization method of directly polymerizing in the presence of a water-soluble polar polymerization initiator to form toner particles.

In particular, when the toner particles are obtained by a so-called polymerization method, the adjustment of the average particle diameter and the sphericity of the toner particles is simple and more preferable.

The number average particle diameter of the inorganic fine particles A is 30.
nm or more and less than 100 nm. When the number average particle diameter of the inorganic fine particles A is less than 30 nm, the inorganic fine particles A are fixed and buried in the toner particle surface in a long-term use,
In addition to not being able to impart appropriate fluidity, the surface properties of the inorganic fine particles A after the silicone oil treatment are changed, and the effect of preventing damage to the fixing member is reduced. Further, when the number average particle diameter of the inorganic fine particles A is 100 nm or more, fine defects are not generated in the fixing member, but fixing defects occur in the initial image sample.

The number average particle diameter of the inorganic fine particles B is 10
0 nm or more and less than 500 nm. When the number average particle diameter of the inorganic fine particles B is less than 100 nm, the effect of adding the inorganic fine particles B does not appear, and the inorganic fine particles A are released from the toner particle surface in the fixing step of long-term continuous printing, which causes deterioration of the fixing member. Become. Further, the number average particle diameter of the inorganic fine particles B is 5
If the thickness is more than 00 nm, a sufficient amount of heat is not supplied to the toner particles at the time of fixing, and a fixing defect occurs.

Further, the compound to be surface-treated for both the inorganic fine particles A and B is preferably silicone oil. When the surface is treated only with a compound other than the silicone oil, it is difficult to simultaneously achieve a plurality of performances such as fluidity, charging characteristics, high transferability, and prevention of loss of the fixing member of the toner. However, as described later, when the inorganic fine particles are subjected to a surface treatment with another compound in addition to the silicone oil treatment, the surface treatment with the other compound may have various effects obtained by the surface treatment with the silicone oil. It does not inhibit.

In the present invention, more preferably, the inorganic fine particles A are silica and the inorganic fine particles B are titanium oxide. As described above, A and B have different functions, and the combination described above allows them to function optimally.

In the present invention, the inorganic fine particles B are preferably titanium oxide having a rutile type crystal structure. Although the detailed reason is unknown, it is considered that the fine particles A cannot be effectively removed by the anatase type titanium oxide because the volume specific resistivity is different between the anatase type and the rutile type.

In order to exhibit the effect of the addition of the inorganic fine particles A and B, the amount of the inorganic fine particles A is preferably 0.03 to 3 parts by weight, and the amount of the inorganic fine particles B is preferably 0.01 to 3 parts by weight based on 100 parts by weight of the toner particles. Parts by weight are preferred.

In the present invention, it is preferable to add fine particles C having a number average particle diameter smaller than that of the inorganic fine particles A. The fine particles C are considered to function as a fluidity improving aid, and when the fine particles C are added, a clearer image can be obtained with respect to the initial image.

In the present invention, the fine particles C are more preferably subjected to a hydrophobic treatment. Since the fine particles C are subjected to the hydrophobic treatment, a good initial image can be obtained regardless of the environment where the temperature and the humidity are different.

When the fine particles C are added, it is preferable to use 0.01 to 3 parts by weight of the fine particles C based on 100 parts by weight of the toner particles.

In the present invention, the toner particles are obtained by a polymerization method and have an average circularity of 0.960 to 0.9.
98, the number average particle diameter of the inorganic fine particles A is 30 nm or more and less than 100 nm, the number average particle diameter of the inorganic fine particles B is 100 nm or more and less than 500 nm, and the number average particle diameter of the fine particles C is smaller than that of the inorganic fine particles A. It is preferable to have.

By the polymerization method, toner particles having a higher average circularity can be easily obtained. Also, since a large amount of wax component can be put into the toner particles,
By the action of the wax component that exists in a trace amount on the toner surface layer,
An effect similar to that obtained when the silicone oil treatment is used for the inorganic fine particles A and the inorganic fine particles B can be expected. However, the purpose of the present invention is not always achieved by the action of only a small amount of the wax component present in the toner surface layer, and it is necessary in the present invention to treat the inorganic fine particles A and B with silicone oil, and these are used in combination with these. It goes without saying that better results can be obtained.

In the present invention, the surface of the electrostatic image holder is charged, an electrostatic latent image is formed on the charged surface of the electrostatic image holder, and the electrostatic latent image is developed with toner. ,
An image forming method for transferring the toner image to a recording material and fixing the toner image on the recording material, wherein the toner image is fixed by pressurizing and heating. And a nip pressure of the heat fixing roller is 5 × 10 ^{4 to} 5 × 1.
Is preferably 0 ⁵ Pa, it is more preferred nip pressure of the heating fixing roller is ^{1 × 10 5 ~4 × 10 5} Pa.

For example, when a plurality of types of toner images such as full-color images are simultaneously fixed, a higher fixing pressure is required than in the case of a mono-color image. Also works best,
Does not cause fine flaws on the fixing roller.

The silicone oil used in the present invention is:
It is generally represented by the following equation,

[0042]

Embedded image R: C ₁ alkyl group -C ₃ R ': alkyl, halogen-modified alkyl, phenyl, silicone oil modified group R of the modified phenyl such as ": an alkyl or alkoxy group of C ₁ -C ₃

For example, dimethyl silicone oil, alkyl-modified silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl silicone oil, fluorine-modified silicone oil and the like can be mentioned.

As the method of treating the silicone oil, a known technique is used. For example, fine silica powder and silicone oil may be directly mixed using a mixer such as a Henschel mixer, or the silicone oil may be sprayed on the base silica. Depending on the method. Alternatively, the silicone oil may be dissolved or dispersed in an appropriate solvent, mixed with the base silica fine powder, and then the solvent may be removed.

In the hydrophobizing treatment used in the present invention, for example, a silane compound is reacted with a hydroxyl group present on the surface of the untreated fine powder by using a silane coupling agent or the like.
This can also be achieved by substituting a hydroxyl group with a siloxyl group or the like. As a method of the hydrophobic treatment, a dry treatment in which a fine powder is made into a cloud shape by stirring or the like and a vaporized silane coupling agent is reacted; the fine powder is dispersed in a solvent, and if necessary, diluted with an appropriate solvent The treatment can be performed by a generally known method such as a wet treatment in which the silane coupling agent thus obtained is dropped.

The silane coupling agent has a general formula

[0047]

Embedded image For example, typically dimethyldichlorosilane,
Trimethylchlorosilane, allyldimethylchlorosilane, hexamethyldisilazane, allylphenyldichlorosilane, benzyldimethylchlorosilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, divinylchlorosilane, dimethylvinyl Chlorosilane and the like can be mentioned.

In the toner of the present invention, as the fine particles C, those widely and generally known as external additives can be used. Specifically, various metal compounds (aluminum oxide, titanium oxide, strontium titanate,
Cerium oxide, magnesium oxide, chromium oxide, tin oxide, zinc oxide, etc., nitrides (silicon nitride, etc.), carbides (silicon carbide, etc.), metal salts (calcium sulfate, barium sulfate, calcium carbonate, etc.), fatty acid metal salts ( Zinc stearate, calcium stearate, etc.), carbon black, silica and the like.

As the fine particles C, various resin fine particles can be used.

In order to obtain the resin fine particles, it is possible to use a conventionally known method, that is, an emulsion polymerization method or a spray drying method. For example, styrene, acrylic acid, methyl methacrylate, butyl acrylate and 2-ethylhexyl acrylate can be used. Resin fine particles having a glass transition point of 80 ° C. or higher obtained by homopolymerizing or copolymerizing a monomer component used for the binder resin for a toner as described above by an emulsion polymerization method can be used.

Further, it may be cross-linked with a cross-linking agent such as divinylbenzene. In order to adjust the specific electric resistance and the triboelectric charge, metals, metal oxides, pigments and the like whose resin particle surfaces do not damage the photoreceptor surface are used. , A surfactant or the like. Further, in the toner production method by the suspension polymerization method, it may be produced simultaneously with the toner particles. Further, it is desirable that the resin fine particles be spherical, but if the resin fine particles work effectively, the resin fine particles may be appropriately flattened, or a part thereof is fixed to the toner particle surface in a flattened shape. You may.

In order to further improve the image quality,
It is also possible to add external additives other than the types.

The toner of the present invention may contain a low softening point substance (wax) inside the toner. As a specific method of encapsulating the low softening point substance, a method of obtaining toner particles by suspension polymerization in an aqueous medium is used, and the polarity of the material in the aqueous medium is lower than that of the main monomer. Is set to a small value, and a small amount of a resin or monomer having a large polarity is added, so that a toner having a so-called core / shell structure in which a material having a low softening point is coated with a shell resin can be obtained.

As a specific method for confirming the core / shell structure, a cured product obtained by sufficiently dispersing a toner in a room-temperature curable epoxy resin and then curing it in an atmosphere at a temperature of 40 ° C. for 2 days is used. After staining with ruthenium oxide and, if necessary, osmium tetroxide, a flaky sample is cut out using a microtome equipped with diamond teeth, and the tomographic morphology of the toner is observed using a transmission electron microscope (TEM). In the present invention, it is preferable to use a ruthenium tetroxide dyeing method in order to provide a contrast between materials by utilizing a slight difference in crystallinity between the low softening point substance used and the resin constituting the outer shell.

The release agent used in the present invention is OH
It is more preferable to use an ester wax from the viewpoint of the transparency of the sheet for P, the low-temperature fixing property at the time of fixing, and the high-temperature offset resistance.

The ester wax used is a binder resin 100
It is preferable to add 3 to 40 parts by weight (more preferably 5 to 35 parts by weight) per part by weight.

The particle size distribution and the particle size of the toner can be controlled by changing the type and amount of a poorly water-soluble inorganic salt or a dispersant acting as a protective colloid, or by mechanical device conditions such as the peripheral speed of the rotor and the number of passes. The predetermined toner of the present invention can be obtained by controlling the stirring conditions such as the shape of the stirring blade, the shape of the container, and the solid content concentration in the aqueous solution.

The polymerizable monomer used in the present invention includes styrene, o (m-, p-)-methylstyrene, m
Styrene monomers such as (p-)-ethylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate,
Propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate (Meth) acrylate monomers such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; ene monomers such as butadiene, isoprene, cyclohexene, (meth) acrylonitrile, and acrylamide The body is preferably used. These can be used alone or in general in the published Polymer Handbook, 2nd edition III-pl39-192 (John Wire
y & Sons), the theoretical glass transition temperature (T
g) is used by appropriately mixing monomers so as to show a temperature of 40 to 80 ° C. If the theoretical glass transition temperature is lower than 40 ° C., problems arise in terms of the storage stability of the toner and the durability stability of the developer. In some cases, the color mixture of each color toner is insufficient, resulting in poor color reproducibility.
The transparency of the HP image is significantly reduced, which is not preferable from the viewpoint of high image quality.

In the present invention, when a toner having a core / shell structure is produced, it is particularly preferable to add a polar resin. The polar resin used in the present invention includes a copolymer of styrene and (meth) acrylic acid,
Maleic acid copolymers, polyester resins and epoxy resins are preferably used. It is particularly preferable that the polar resin does not contain an unsaturated group capable of reacting with a monomer in the molecule.

As the polymerization initiator used in the present invention, for example, 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile,
1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis-4-methoxy-2,4-
Azo-based polymerization initiators such as dimethylvaleronitrile and azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-
A peroxide-based polymerization initiator such as dichlorobenzoyl peroxide and lauroyl peroxide is used.

The amount of the polymerization initiator to be added varies depending on the target component ratio of the present invention, but is generally 0.5 to 20% by weight, more preferably 0.5 to 10% by weight, based on the monomer. % Used. Although the type of the initiator slightly varies depending on the polymerization method, it is used alone or in combination with reference to the 10-hour half-life temperature.

In order to control the molecular weight distribution of the binder resin for toner of the present invention, it is preferable to further use a known crosslinking agent, chain transfer agent, polymerization inhibitor and the like.

In the present invention, an outermost shell resin layer may be further provided on the surface of the toner. The glass transition temperature of the outermost shell resin layer is preferably designed to be equal to or higher than the glass transition temperature of the outer shell resin layer in order to further improve blocking resistance, and it is preferable that the outermost shell resin layer is crosslinked so as not to impair fixability. . The outermost resin layer preferably contains a polar resin and a charge control agent for improving the chargeability.

The method for providing the outermost shell layer is not particularly limited, but includes, for example, the following methods.

1. In the second half or after the end of the polymerization reaction, if necessary, a monomer in which a polar resin, a charge control agent, a cross-linking agent, etc. are dissolved and dispersed is added to the reaction system, the monomer is adsorbed, polymerized particles are added, and a polymerization initiator is added for polymerization. Method.

2. If necessary, an emulsion polymerization particle or a soap-free polymerization particle composed of a monomer containing a polar resin, a charge control agent, a cross-linking agent, etc. is added to the reaction system, and aggregated on the surface of the polymerization particle.If necessary, heat or the like is used. How to stick.

3. A method in which emulsion polymerized particles or soap-free polymerized particles comprising a monomer containing a polar resin, a charge control agent, a cross-linking agent, and the like, if necessary, are dry-mechanically fixed to the toner particle surfaces.

As the colorant used in the present invention, a black colorant prepared by using carbon black, a magnetic substance, and a yellow / magenta / cyan colorant shown below is used. Examples of yellow colorants include condensed azo compounds, isoindolinone compounds, anthraquinone compounds,
Compounds represented by azo metal complexes, methine compounds and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 6
2, 74, 83, 93, 94, 95, 109, 110,
111, 128, 129, 147, 168, 180 and the like are preferably used.

Examples of the magenta colorant include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specifically, C.I.
I. Pigment Red 2, 3, 5, 6, 7, 23, 4
8: 2, 48: 3, 48: 4, 57: 1, 81: 1, 1
22, 144, 146, 166, 169, 177, 18
4, 185, 202, 206, 220, 221, 254
Is particularly preferred.

As the cyan coloring agent, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds and the like can be used. Specifically, C.I. I.
Pigment Blue 1, 7, 15, 15: 1, 15: 2,
15: 3, 15: 4, 60, 62, 66, etc. can be particularly preferably used.

These colorants can be used alone or as a mixture or in the form of a solid solution. In the case of a color toner, the colorant of the present invention is selected from the viewpoints of hue angle, saturation, lightness, weather resistance, OHP transparency, and dispersibility in the toner. The amount of the coloring agent is 1 to 100 parts by weight of the resin.
Used in an amount of up to 20 parts by weight.

When a magnetic material is used as the black colorant, unlike other colorants, 40 to 100 parts by weight of the resin is used.
Used by adding 150 parts by weight.

The charge control agents used in the present invention include:
Although a known toner can be used, in the case of a color toner, a charge control agent which is colorless, has a high toner charging speed, and can stably maintain a constant charge amount is particularly preferable. Furthermore,
In the case of a toner obtained by a polymerization method, a charge control agent having no polymerization inhibition and having no solubilized substance in an aqueous system is particularly preferable.

Specific examples of the negative compound include metal compounds of salicylic acid, naphthoic acid, dicarboxylic acid and derivatives thereof, sulfonic acid, high molecular compounds having carboxylic acid in the side chain, boron compounds, urea compounds, silicon compounds as negative compounds. A compound, calixarene and the like can be used, and a quaternary ammonium salt, a high molecular compound having the quaternary ammonium salt in a side chain, a guanidine compound, an imidazole compound and the like are preferably used as the positive system.

The charge control agent is preferably added in an amount of 0.5 to 10 parts by weight based on 100 parts by weight of the resin. However, in the present invention, the addition of the charge control agent is not essential,
When using the two-component developing method, use the frictional charging with the carrier, and when using the non-magnetic one-component blade coating developing method, positively use the frictional charging with the blade member or the sleeve member. Therefore, it is not always necessary to include a charge control agent in the toner.

When suspension polymerization is used as the toner production method of the present invention, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate may be used as a dispersant, for example, as an inorganic oxide. , Magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, magnetic material, ferrite and the like.
Examples of the organic compound include polyvinyl alcohol,
Gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salts of carboxymethylcellulose, starch and the like are used by being dispersed in an aqueous phase.

These dispersants are used in the polymerizable monomer composition 10
It is preferable to use 0.2 to 10.0 parts by weight with respect to 0 parts by weight.

As these dispersants, commercially available ones may be used as they are, but in order to obtain finely dispersed particles having a uniform particle size, the inorganic compound is formed under high-speed stirring in a dispersion medium. You can also get.

For example, in the case of tricalcium phosphate, a dispersant suitable for a suspension polymerization method can be obtained by mixing an aqueous solution of sodium phosphate and an aqueous solution of calcium chloride under high-speed stirring.

Further, these dispersants may be added in an amount of 0.001 to 0.
One part by weight of a surfactant may be used in combination. Specifically, commercially available nonionic, anionic, and cationic surfactants can be used, and examples thereof include sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, and olein. Calcium acid and the like are preferably used.

The method for producing the toner of the present invention includes:
After uniformly dispersing the release agent, colorant, charge control agent, etc., made of resin, low softening point substance, using a pressure kneader, extruder or media disperser, it is made to collide with the target mechanically or under a jet stream. There is a method of producing a toner by a so-called pulverization method in which after finely pulverizing to a desired toner particle diameter, the particle size distribution is further sharpened through a classification step to obtain a toner.

As a method for producing a polymerized toner, a releasing agent, a colorant, a charge control agent, a polymerization initiator and other additives are added to a polymerizable monomer, and the mixture is homogenized by a homogenizer, an ultrasonic disperser or the like. Is dissolved or dispersed in an aqueous phase containing a dispersion stabilizer using a homomixer or the like. The granulation is stopped when the desired toner particle size is obtained from the droplets of the monomer composition. Thereafter, by the action of the dispersion stabilizer, the particles may be stirred to such an extent that the particle state is maintained and the particles are prevented from settling. The polymerization temperature is 40 ° C. or higher, generally 50 to 90 ° C.
The polymerization is carried out at a temperature set to. In addition, for the purpose of obtaining the molecular weight distribution of the present invention, the temperature may be raised in the latter half of the polymerization reaction, and further, in the latter half of the reaction to remove unreacted polymerizable monomers and by-products, or the Later, a part of the aqueous medium may be distilled off. After the reaction, the generated toner particles are collected by washing and filtration, and dried. In the suspension polymerization method, usually, 300 to 30 parts of water is added to 100 parts by weight of the monomer composition.
It is preferable to use 00 parts by weight as a dispersion medium.

The average particle size and particle size distribution of the toner can be measured by various methods such as Coulter Counter TA-II or Coulter Multisizer (manufactured by Coulter Inc.). In the present invention, the Coulter Counter TA-I is used.
An interface (manufactured by Nikkaki) that outputs the number distribution and volume distribution using type I (manufactured by Coulter) and PC980
1 A personal computer (manufactured by NEC) is connected, and a 1% aqueous NaCl solution is prepared using primary grade sodium chloride as an electrolytic solution. For example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measuring method, 100 to 150 m of the electrolytic aqueous solution is used.
A surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant in an amount of 0.1 to 5 ml, and a measurement sample is further added in an amount of 2 to 20 mg. The electrolytic solution in which the sample is suspended is subjected to dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser, and the volume and number of toner particles of 2 μm or more are measured using a 100 μm aperture as a rear aperture by the Coulter Counter TA-II. Then, a volume distribution and a number distribution were calculated. Then, a volume-based weight average particle diameter (D4: the median value of each channel is a representative value of the channel) obtained from the volume distribution according to the present invention was obtained.

As the flow type particle image measuring device of the present invention, a flow type particle image measuring device (F
PIA-1000) was used. About 0.02 g of the toner for measuring the average circularity was weighed and uniformly dispersed in ion-exchanged water (about 10 ml, 20 ° C.) containing a small amount of a surfactant.
As a means for dispersing, an ultrasonic disperser UH-50 manufactured by SMT Co., Ltd. (vibrator is a 5φ titanium alloy chip) was used. Dispersion time should be 5 minutes or more,
The dispersion medium was appropriately cooled so that the temperature did not reach 40 ° C. or higher. Using the above-mentioned flow type particle image measuring apparatus, 1000 or more toner particles were measured, and the average circularity and its distribution were calculated using the following equation.

[0085]

(Equation 2)

The average particle size of the fine particles other than the toner particles of the present invention was calculated by using a transmission electron microscope (TEM), dispersing and embedding in an epoxy resin, and then thinly sliced to obtain a photographic image of the particles (FIG. Magnification 10,000-100,000
Times). After randomly extracting 20 to 50 samples of this photographic image, the diameter of the spherical particles and the major axis of the fan-shaped particles were defined as the particle diameter of the spherical particles, and the arithmetic average was calculated to calculate the number average particle diameter. .

For evaluation of the developer of the present invention, a modified model of commercially available Canon LBP-2030 was used. FIG. 1 shows the outline. That is, an intermediate transfer drum is provided at the position 25, and a plurality of images can be transferred collectively using the intermediate transfer body. Further, improvements were made to the fixing device 29 and the paper carrying system so that the nip pressure at the time of fixing can be changed to an arbitrary value.

As the fixing roller 29a of the fixing device 29, one having a core shaft made of aluminum or the like covered with two types of layers was used. A high temperature vulcanized silicone rubber (HTV silicone rubber) was used as an elastic layer in the lower layer. The thickness of the elastic layer was 2.1 mm, and the rubber hardness was 3 ° (JIS-A). On the other hand, a release layer made of a thin film of a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA) by spray coating was used as an upper layer. The thickness of the thin film was 20 μm.

Similarly to the fixing roller 29a, the pressure roller 29b of the fixing device 29 has a structure in which the core axis is covered with a lower silicone rubber elastic layer and an upper fluororesin release layer, and has the same material, thickness, and physical properties. Was used.

Although the nip width of the fixing portion fluctuates with the nip pressure, it was set to be 5.0 mm or more, and the surface temperature of the fixing roller during standby was set to 180 ° C. The fixing oil application mechanism was removed.

In FIG. 1, after uniformly charging the surface of a photosensitive drum 21 as a latent image holding member using a charging roller 22, a laser beam E emitted from a light source device LS is used.
To form an electrostatic latent image on the photosensitive drum 21. The electrostatic latent image is stored in the developing device 24 (24y, 24m, 24c,
24Bk) to form a toner image. The toner image is transferred to the intermediate transfer body 25.

As the intermediate transfer member 25, a drum-shaped one is used, and a holding member is stretched on the outer peripheral surface, and a conductivity-imparting member such as carbon black, zinc oxide, tin oxide,
What has an elastic layer (for example, nitrile butadiene rubber) in which silicon carbide or titanium oxide is sufficiently dispersed is used. A belt-shaped intermediate transfer member may be used.

In the transfer from the photosensitive drum 21 to the intermediate transfer member 25, a transfer current is obtained by applying a bias from a power source (not shown) to the core metal 23 as a support member of the intermediate transfer member 25, and the toner image is transferred. Is performed. Corona discharge or roller charging from the back of the holding member may be used.

The toner image on the intermediate transfer body 25 is collectively transferred onto the recording material P by the transfer means 28. As the transfer unit, a contact electrostatic transfer unit using a corona charger, a transfer roller, or a transfer belt is used.

The same developing agent (toner) was filled in 200 g each of the four developing cartridges (24y, 24m, 24c, 24Bk) of the Canon LBP-2030 to obtain a study cartridge. As the recording material P, a commercially available CLC paper A4 (81.4 g / m ^{2 from} Canon Sales Co.) was used, and continuous feeding was performed in the full color mode at a printing rate of 3% using the tray 27.

Initial, 500 sheets, 1000 sheets, 300 sheets
At 0, 5000, and 7000 sheets, evaluation of “image density”, “fog”, “gradation”, and “reproducibility of isolated dots” were performed as described below. Regarding “image fixability”, continuous paper passing is performed by replacing the used examination cartridge with an unused examination cartridge every time 7000 sheets are printed.
21,000 sheets, 35,000 sheets, 49000 sheets, 6
At the time of 3000 sheets, evaluation was performed by the method described below.

Regarding “image fixability”, all solid images,
That is, the tenth image of the ten consecutive printed images drawn on the entire developable area was used as a sample. For each sample, 5mm x
An image area of 5 mm square was set, and the part was rubbed reciprocally 10 times with a load of about 500 g using an unused plastic eraser PE-01A (manufactured by Tombow Pencil). The image density of the portion before and after the rubbing was measured using a reflection densitometer (TOKYO DENSHOKU CO., LTD., REFLECOMETER ODEL TC-6D).
S) (measured by Ds-Dr when the density before rubbing is Ds and the density after rubbing is Dr). An image density difference of 4% or less is an image having substantially good fixability.
If it exceeds 0%, an image having a problem in fixing property is obtained.

The "image density" was represented by the reflection density of a 5 mm square solid image. “Fog” is a reflection type densitometer (REFLECTOMETER ODEL TC-6D manufactured by TOKYO DENSHOKU CO., LTD.).
(S) (the fog amount is Ds−Dr when the worst value of the reflection density of the white background portion after printing is Ds and the average reflection density of the paper before printing is Dr) (fog amount 2).
% Or less is a good image with substantially no fog, and 5%
When the number of images exceeds 1, the image is fuzzy and unclear. ).

The evaluation of "gradation" was based on the measurement of eight types of image densities having different pattern forming methods as shown in FIG.

From the viewpoint of gradation reproducibility, a desirable density range of each pattern is preferably as follows.
Evaluation was performed from this viewpoint. Pattern 1 0.10 to 0.15 Pattern 2 0.15 to 0.20 Pattern 3 0.20 to 0.30 Pattern 4 0.25 to 0.40 Pattern 5 0.55 to 0.70 Pattern 6 0.65 ~ 0.80 pattern 7 0.75 ~ 0.90 pattern 8 1.30 ~

The criteria were as follows: those satisfying all of the above-mentioned areas were excellent, those deviating by one were acceptable, and those deviating by two or more were not.

The "reproducibility of one isolated dot" relating to a graphic image or the like was evaluated using the image shown in FIG. That is, the more the latent image is blurred, the more the development area is expanded and the density is increased. Judgment criteria: 100x magnified image of the obtained image, excellent if there is almost no toner scattering, excellent if it scatters around the dot, acceptable if the dot outline is not clear due to toner scattering And In this evaluation, the resolution was set to 600 dpi.

[0103]

EXAMPLES The present invention will be described in more detail with reference to the following examples, which do not limit the present invention in any way.

Example 1 450 parts by weight of a 0.1 M Na ₃ PO ₄ aqueous solution was added to 700 parts by weight of ion-exchanged water, heated to 50 ° C.
Using a homomixer (manufactured by Tokushu Kika Kogyo)
The mixture was stirred at 00 rpm. 1.0M-CaCl ₂
70 parts by weight of the aqueous solution was gradually added to obtain an aqueous medium containing a calcium phosphate salt.

On the other hand, (monomer) 170 parts by weight of styrene 30 parts by weight of n-butyl acrylate (colorant) I. Pigment Blue 15:15 15 parts by weight (charge controlling agent) salicylic acid metal compound 2 parts by weight (polar resin) saturated polyester 20 parts by weight (acid value 10, peak molecular weight: 15,000) (release agent) behenyl stearate 30 parts by weight Part (Crosslinking agent) 0.3 parts by weight of divinylbenzene The above formulation was heated to 50 ° C., and uniformly dissolved and dispersed at 9000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo). Into this, 3 parts by weight of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) was dissolved to prepare a polymerizable monomer composition.

The polymerizable monomer composition was charged into the aqueous medium and stirred at 8000 rpm with a TK homomixer at 50 ° C. in an N ₂ atmosphere to granulate the polymerizable monomer composition. did.

Thereafter, the temperature was raised to 60 ° C. in 2 hours while stirring with a paddle stirring blade, and after 4 hours, the temperature was raised at a rate of 40 ° C./H.
r. At 80 ° C. for 4 hours. After completion of the polymerization reaction, the remaining monomer was distilled off under reduced pressure, and after cooling, hydrochloric acid was added to dissolve the calcium phosphate salt, followed by filtration, washing with water, and drying to give a weight average particle size of 6.5 μm and an average circularity of 0. .9
As a result, 85 colored toner particles were obtained.

For 100 parts by weight of the toner particles, as the inorganic fine particles A, silica having a number average particle diameter of 40 nm and having been subjected to a coupling agent and silicone oil treatment was added.
5 parts by weight; number average particle diameter of 170 n as inorganic fine particles B
0.4 parts by weight of rutile-type titanium oxide treated with silicone oil at m;
1.0 part by weight of silica treated with a coupling agent at m; 1.0 part by weight of strontium titanate having a number average particle size of 500 nm as fine particles D, and uniformly using a Henschel mixer manufactured by Mitsui Mining Co., Ltd. The developer was obtained by stirring.

Evaluation of the obtained developer was conducted using commercially available Canon L.
This was performed using a modified machine of BP-2030. The nip pressure of the fixing device was 1.5 × 10 ⁵ Pa.

The results are shown in Table 1.

Example 2 After obtaining colored toner particles in the same manner as in Example 1, the same formulation as in Example 1 was carried out using a Henschel mixer with the same formulation except that the fine particles C described in Example 1 were not used. And uniformly stirred to obtain a developer.

Thereafter, image evaluation was performed under the same conditions as in Example 1.

Table 1 shows the evaluation results of the obtained developers.
It was noted in.

Example 3 After obtaining colored toner particles in the same manner as in Example 1, the same formulation as in Example 1 was carried out using a Henschel mixer with the same formulation except that the fine particles D described in Example 1 were not used. And uniformly stirred to obtain a developer.

Thereafter, image evaluation was performed under the same conditions as in Example 1.

Table 1 shows the evaluation results of the obtained developers.
It was noted in.

Example 4 After obtaining colored toner particles in the same manner as in Example 1, the fine particles A described in Example 1 were not used. Instead, inorganic fine particles A1 were treated with silicone oil having a number average particle diameter of 40 nm. A developer was obtained by using a Henschel mixer and uniformly stirring under the same conditions as in Example 1 except that 0.5 part by weight of the silica to which only the silica was applied was used.

Thereafter, image evaluation was performed under the same conditions as in Example 1.

Table 1 shows the evaluation results of the obtained developers.
It was noted in.

Example 5 After obtaining colored toner particles in the same manner as in Example 1, the fine particles B described in Example 1 were not used. Instead, inorganic fine particles B1 were treated with silicone oil having a number average particle diameter of 450 nm. The same formulation was used except that 0.3 parts by weight of rutile-type titanium oxide subjected to the above was used, and the mixture was uniformly stirred under the same conditions as in Example 1 using a Henschel mixer to obtain a developer.

Thereafter, image evaluation was performed under the same conditions as in Example 1.

Table 1 shows the evaluation results of the obtained developers.
It was noted in.

Example 6 Colored toner particles were obtained in the same manner as in Example 1, and the same formulation as in Example 1 was carried out using a Henschel mixer.
The mixture was stirred uniformly under the same conditions as described above to obtain a developer.

Evaluation of the obtained developer was conducted using commercially available Canon L.
This was performed using a BP-2030 modified machine. The nip pressure of the fixing device was 5.0 × 10 ⁵ Pa.

Table 1 shows the evaluation results of the obtained developers.
It was noted in.

Example 7 After obtaining colored toner particles in the same manner as in Example 1, the fine particles C described in Example 1 were not used, and instead, a surface treatment with a number average particle size of 60 nm was performed as the inorganic fine particles C1. A developer was obtained by using a Henschel mixer and uniformly stirring under the same conditions as in Example 1 except that 1.0 part by weight of untreated polystyrene fine powder was used.

Thereafter, image evaluation was performed under the same conditions as in Example 1.

Table 1 shows the evaluation results of the obtained developers.
It was noted in.

Example 8 A four-necked flask was charged with 180 parts by weight of nitrogen-purged water and 20 parts by weight of a 0.2 wt% aqueous solution of polyvinyl alcohol, and then 75 parts by weight of styrene and acrylic acid-n-
25 parts by weight of butyl, 3.0 parts by weight of benzoyl peroxide and 0.01 part by weight of divinylbenzene were added, and stirred to form a suspension. Thereafter, after the inside of the flask was replaced with nitrogen, the temperature was raised to 80 ° C. and maintained at the same temperature for 10 hours to carry out a polymerization reaction. After washing the polymer with water, the polymer was dried under reduced pressure while maintaining the temperature at 65 ° C. to obtain a resin. 88wt of this resin
%, Metal-containing azo dye 2wt%, carbon black 5w
t% and 8 wt% of paraffin wax were mixed by a fixed-tank type dry mixer, and melt kneading was performed by a twin screw extruder while suction was connected to a suction port at a vent port.

This melt-kneaded product was crushed by a hammer mill to obtain a crushed toner composition of 1 mm mesh pass.
Further, the coarsely crushed material is crushed by a mechanical crusher to a volume average diameter of 20 to 30 μm, and then crushed by a jet mill utilizing collision between particles in a swirling flow. The toner composition was modified by mechanical and mechanical shearing force and classified by a multi-stage classifier to obtain toner particles having a weight average particle size of 7.0 μm and an average circularity of 0.958.

To 100 parts by weight of the toner particles, as inorganic fine particles A, silica having a number average particle diameter of 40 nm and having been subjected to a coupling agent and silicone oil treatment was added.
8 parts by weight; as inorganic fine particles B, number average particle diameter 170 n
0.4 parts by weight of rutile-type titanium oxide treated with silicone oil at m;
1.3 parts by weight of silica treated with a coupling agent at m; 1.0 part by weight of strontium titanate having a number average particle diameter of 500 nm as fine particles D, and using a Henschel mixer manufactured by Mitsui Mining Co., Ltd. The developer was obtained by stirring.

Thereafter, image evaluation was performed under the same conditions as in Example 1.

Table 1 shows the evaluation results of the obtained developers.
It was noted in.

Comparative Example 1 The same procedure as in Example 8 was carried out up to the point where a coarsely crushed toner composition was obtained. Toner particles having a particle size of 9.0 μm and an average circularity of 0.945 were obtained.

With respect to 100 parts by weight of the toner particles, as the inorganic fine particles A, silica having a number average particle diameter of 40 nm and having been subjected to a coupling agent and silicone oil treatment was used.
5 parts by weight; number average particle diameter of 170 n as inorganic fine particles B
0.4 parts by weight of rutile-type titanium oxide treated with silicone oil at m;
1.0 part by weight of silica treated with a coupling agent at m; 1.0 part by weight of strontium titanate having a number average particle size of 500 nm as fine particles D, and uniformly using a Henschel mixer manufactured by Mitsui Mining Co., Ltd. The developer was obtained by stirring.

Thereafter, image evaluation was performed under the same conditions as in Example 1.

Table 1 shows the evaluation results of the obtained developers.
It was noted in.

Comparative Example 2 After obtaining colored toner particles in the same manner as in Example 1, the same conditions as in Example 1 were used using a Henschel mixer with the same formulation except that the fine particles A described in Example 1 were not used. And uniformly stirred to obtain a developer.

Thereafter, image evaluation was performed under the same conditions as in Example 1.

Table 1 shows the evaluation results of the obtained developers.
It was noted in.

Comparative Example 3 After obtaining colored toner particles in the same manner as in Example 1, the same conditions as in Example 1 were used using a Henschel mixer with the same formulation except that the fine particles B described in Example 1 were not used. And uniformly stirred to obtain a developer.

Thereafter, image evaluation was performed under the same conditions as in Example 1.

Table 1 shows the evaluation results of the obtained developers.
It was noted in.

[0144] After obtaining the colored toner particles in the same manner as in Comparative Example 4 Example 1, without using the fine particles A described in Example 1, but instead, the inorganic fine particles A ^- as the silicone oil by the number average particle diameter 60nm A developer was obtained by stirring uniformly under the same conditions as in Example 1 using a Henschel mixer with the same formulation except that 0.3 part by weight of untreated silica was used.

Thereafter, image evaluation was performed under the same conditions as in Example 1.

Table 1 shows the evaluation results of the obtained developers.
It was noted in.

[0147] After obtaining the colored toner particles in the same manner as in Comparative Example 5 Example 1, Example without using fine particles B according to 1, alternatively, the inorganic fine particles B ^- as the silicone oil by the number average particle diameter 270nm A developer was obtained by uniformly stirring using a Henschel mixer under the same conditions as in Example 1 except that 0.3 part by weight of rutile-type titanium oxide not subjected to the treatment was used.

Thereafter, image evaluation was performed under the same conditions as in Example 1.

Table 1 shows the evaluation results of the obtained developers.
It was noted in.

[0150]

[Table 1]

[0151]

According to the present invention, it is possible to provide a toner which does not cause loss on the fixing member during running, without impairing the fluidity and charging characteristics.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an image forming apparatus suitable for the present invention.

FIG. 2 shows a pattern used for evaluation of gradation.

FIG. 3 shows an image used for evaluation of dot reproducibility.

[Description of Signs] 21 electrostatic image holder 22 charging means 24 developing device 25 intermediate transfer member 26 cleaner LS laser scanner E exposure P recording material

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI G03G 9/08 375

Claims (12)

[Claims] 1. A toner having at least a binder resin and a colorant and two types of inorganic fine particles A and B having different number average particle diameters, wherein the toner particles have a weight average particle diameter of 2 And the average circularity is from 0.955 to 0.998. The inorganic fine particles A have a number average particle size of 30 nm or more and 100 or more.
The inorganic fine particles B have a number average particle diameter of 100 nm or more and 50 nm or less.
A toner comprising hydrophobic titanium oxide fine particles having a rutile crystal structure of less than 0 nm. 2. The inorganic fine particles A and the inorganic fine particles B
2. The toner according to claim 1, wherein the toner is treated with a silicone oil. 3. The toner according to claim 1, wherein the toner further has fine particles C having a number average particle size smaller than the inorganic fine particles A. 4. The toner according to claim 3, wherein the fine particles C are an inorganic compound subjected to a hydrophobic treatment. 5. The toner particles are obtained by a polymerization method,
The toner according to any one of claims 1 to 4, wherein the average circularity is from 0.960 to 0.998. 6. A surface of the electrostatic image carrier is charged, an electrostatic latent image is formed on the charged surface of the electrostatic image carrier, and the electrostatic latent image is developed with toner to form a toner image. And transferring the toner image to a recording material with or without an intermediate transfer member and fixing the toner image to the recording material, wherein the toner contains at least a binder resin and a colorant. Toner particles and two types of inorganic fine particles A and B having different number average particle diameters. The toner particles have a weight average particle diameter of 2 to 8 μm and an average circularity of 0.955. The inorganic fine particles A have a number average particle size of 30 nm or more and 100 or more.
The inorganic fine particles B have a number average particle diameter of 100 nm or more and 50 nm or less.
An image forming method comprising hydrophobic titanium oxide fine particles having a rutile crystal structure of less than 0 nm. 7. The inorganic fine particles A and the inorganic fine particles B
The image forming method according to claim 6, wherein the image is treated with a silicone oil. 8. The image forming method according to claim 6, wherein the toner further has fine particles C having a number average particle diameter smaller than the inorganic fine particles A. 9. The image forming method according to claim 8, wherein the fine particles C are an inorganic compound subjected to a hydrophobic treatment. 10. The image forming method according to claim 6, wherein a heat fixing roller is used for fixing the toner image. 11. The nip pressure of the heat fixing roller is 5 × 1
0 ^4-5 The image forming method according to any one of claims 6 to 10, characterized in that × is 10 ⁵ Pa. 12. The nip pressure of the heat fixing roller is 1 × 1
The image forming method according to claim 6, wherein the pressure is 0 ⁵ to 4 × 10 ⁵ Pa.