JP2000267341A - Electrostatic latent image developing toner and method and device for formation of image using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the stability for a long time when a toner produced by melting and depositing resin particles in an aq. medium is used, by controlling the particle size of resin particles which constitute the toner and the particle size of a large-size external additive to satisfy specified relation. SOLUTION: In an electrostatic latent image developing toner consisting of an external additive and color particles produced by melting and depositing at least resin particles in an aq. medium, the number average primary particle size (A nm) of the external additive and the weight average particle size (B nm) of the resin particles satisfy the relation of 0.1<=B/A<=1.0 and B=50 to 2,000 nm. As for the fine particles used as the external additive, various kinds of inorg. fine particles, org. fine particles or the like can be used. As for the inorg. fine particles, for example, oxides such as silica, alumina, titania and zirconia, nitrides and borides can be used, and as for the org. fine particles, for example, a styrene resin, styrene/acrylic resin, polyester resin and urethane resin can be used. Thus, decrease in the max. density or production of fog can be prevented even for long-term use.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electrostatic latent image developing toner, and an image forming method and an image forming apparatus using the same.

[0002]

2. Description of the Related Art In recent years, image forming techniques such as copying machines, printers, and facsimile machines have been remarkably developed, and the most frequently used one belongs to an electrostatic image forming method represented by an electrophotographic system. It is.

[0003] The reason is that an electrostatic image forming method such as an electrophotographic method can obtain a high-quality image at a high speed, can form not only a monochrome image but also a color image, and has a durability that can withstand long-term use. , Have stability.

However, with the improvement in performance of related technologies such as personal computers, the required performance level is increasing year by year, and further improvement and performance improvement are required to satisfy the demand.

It is needless to say that it is preferable to reduce the particle size of the electrostatic latent image developing toner (hereinafter, also simply referred to as toner) in order to achieve higher image quality. However, when manufacturing a toner having a small particle size, the conventional method of mixing, kneading, and pulverizing by mixing a resin, a colorant, and the like requires excessive energy at the time of pulverization and requires a large cost. In addition, there is a problem that a large classification loss occurs in a classification step after pulverization. For this reason, for example, JP-A-63-186253 and JP-A-63-282749.
There has been proposed a method for producing a toner by so-called polymerization toner described in Japanese Patent Application Laid-Open No. Hei 7-146583 and the like, particularly by associating resin particles and the like in an aqueous medium. In this method, the particle size of the toner can be adjusted in the aqueous medium by the degree of association of the particles. Therefore, as a method for producing a small particle size toner, there is no generation of fine powder or a large amount of loss, and the production cost is low. It can be said that this is an effective manufacturing method that can be performed.

However, since the toner prepared by this method is produced by associating particles, it is not necessarily composed of only a completely fused interface, so that it can be used for a long time. In this case, a phenomenon may occur in which the powder is crushed due to the stirring energy inside the developing device or the collision energy due to the mixing with the toner and the charging member, thereby generating fine powder. When this phenomenon occurs, the fine powder adheres to the charging member or the developing device, and reduces the chargeability to the toner. Further, since the fine powder is used, the adherence to the photoconductor increases, and the fine powder adheres to the photoconductor. This causes a problem of generating image defects such as black spots and white spots.

As described above, although a toner prepared by associating resin particles with a small particle diameter by an association method has an advantage in productivity, it has the above-mentioned problems and is not completely satisfactory in practical use.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art as described above.

That is, an object of the present invention is to improve long-term stability when a toner obtained by fusing resin particles in an aqueous medium is used. Provided is an electrostatic latent image developing toner capable of forming a stable image without lowering the maximum density or generating fogging and without generating image defects, and an image forming method and an image forming apparatus using the same. It is in.

[0010]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that, in a toner for developing an electrostatic latent image obtained by fusing resin particles in an aqueous medium, the resin particles constituting the toner are used. The inventors have found that the above problem can be solved by setting the particle size and the particle size of the large particle size external additive in a specific relationship, and have completed the present invention.

That is, the above object is achieved by adopting one of the following constitutions.

[1] In a toner for developing an electrostatic latent image comprising at least colored particles obtained by fusing resin particles in an aqueous medium and an external additive, the number average primary particle diameter (An) of the external additive
m) and the weight average particle size (Bnm) of the resin particles have the following relationship:

0.1 ≦ B / A ≦ 1.0 B = 50-2000 nm [2] The toner for developing an electrostatic latent image according to [1], wherein the external additive is organic fine particles.

[3] The toner for developing an electrostatic latent image according to [1], wherein the external additive is a titanate compound.

[4] The toner for developing an electrostatic latent image according to [1], wherein the external additive is titanium oxide.

[5] The toner for developing an electrostatic latent image according to [1], wherein the external additive is silica.

[6] The toner for developing an electrostatic latent image has a volume average particle diameter of 3 to 9 μm, and the shape factor of the toner represented by the following equation is in a range of 1.3 to 2.2. And toner particles having a shape factor in the range of 1.5 to 2.0
The toner for developing an electrostatic latent image according to any one of [1] to [5], wherein the toner is 0% by number or more.

Shape factor = ((maximum diameter / 2) ² × π) / projected area [7] An unfixed toner image formed on the photoreceptor through the steps of uniform charging, image exposure, and development is transferred onto a recording material. In the image forming method of transferring and post-fixing, an electrostatic latent image developing toner composed of colored particles obtained by fusing at least resin particles in an aqueous medium and an external additive is used as a developer. An image forming method, wherein the number average primary particle diameter (Anm) and the weight average particle diameter (Bnm) of the resin particles have the following relationship.

0.1 ≦ B / A ≦ 1.0 B = 50-2000 nm [8] Transfer the unfixed toner image formed on the photoconductor through the steps of uniform charging, image exposure and development to the recording material In the image forming apparatus to be fixed afterwards, a toner for developing an electrostatic latent image composed of colored particles obtained by fusing at least resin particles in an aqueous medium and an external additive is used as a developer. Average primary particle diameter (Anm) and weight average particle diameter of resin particles (B
nm) having the following relationship.

0.1 ≦ B / A ≦ 1.0 B = 50-2000 nm As a result of intensive studies, the present inventors have found that a toner obtained by fusing resin particles in an aqueous medium has a long-term stability. To ensure that the relationship with the external additive added to the surface is important, to further find that the relationship with the particle size of the resin particles for fusing in an aqueous medium is important, The present invention has been completed.

Although the reason is not clear, the present inventors have presumed that a problem occurs due to the following reasons. That is, the toner obtained by fusing the resin particles in the aqueous medium has fine irregularities on the surface. Further, there may be a case where the fusion between the resin particles is not complete. When stress is applied to this portion, local stress is likely to be applied to the external additive present in the convex portion, and the external additive may be buried in that portion, and the stress on the toner may become excessive due to the decrease in fluidity. Therefore, a phenomenon that toner is crushed is caused, and the above problem occurs. As a result, a change in the chargeability of the toner occurs, and a long-term use causes a decrease in the toner charge amount due to burying of the external additive and a decrease in the chargeability due to fusion of the generated fine powder to the charging member. In addition, a phenomenon that fog increases occurs. Further, the generated fine powder adheres to the photoreceptor, thereby causing image defects such as black spots and white spots.

It is well known that the external additive can be prevented from being buried by adding a large particle size external additive. However, in the toner obtained by fusing the resin particles as in the present invention, since there are fine irregularities, the adhesiveness between the external additive having a large particle diameter and the toner itself is reduced, and the desorption thereof is reduced. It often occurs, and the problem of in-flight contamination is likely to occur. Due to such a problem, an external additive having a large particle size cannot be easily added to the toner of the present invention.

As a result of intensive studies, the present inventors have found a countermeasure by estimating the mechanism by which the external additive having a large particle diameter desorbs. In order to effectively retain the large particle size external additive on the toner surface of the present invention, it is necessary to increase the contact probability between the toner surface and the large particle size external additive. It has been found that it is necessary to specify the relationship between the particle size of the powder and the external additive.

The reason why the effects of the present invention can be obtained is as follows.
Although not always clear, by using an external additive that is larger than the constituent resin particles, the plurality of resin particles can come into contact with the large-diameter external additive. It is presumed that this makes it possible to hold the external additive between the fine projections existing on the surface and to improve the adhesion to the toner, thereby preventing desorption.

Further, in the present invention, more specific effects can be exhibited by using a specific shape of the toner.

The number average primary particle diameter of the external additive having a large particle diameter according to the present invention is determined by observation with a transmission electron microscope.
Observe at a magnification of 00 times and use the one measured by image analysis. In the present invention, those having a thickness of 50 to 5000 nm, preferably 80 to 2000 nm can be used.

As the material constituting the fine particles used for the external additive, various inorganic fine particles, organic fine particles and the like can be used.

Examples of the inorganic fine particles include various oxides, nitrides, borides, and the like. For example, silica, alumina, titania, zirconia, barium titanate, aluminum titanate, strontium titanate,
Magnesium titanate, 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, boron nitride, etc. can give. Especially titanate compounds,
Titanium oxide, silica and the like show excellent characteristics.

Further, the above-mentioned inorganic fine particles may be subjected to a hydrophobic treatment. In the case of performing the hydrophobic treatment, it is preferable to perform the hydrophobic treatment with a so-called coupling agent such as various titanium coupling agents and silane coupling agents, or silicone oil. Further, it is also preferable to carry out a hydrophobic treatment with a metal salt of a higher fatty acid such as aluminum stearate, zinc stearate and calcium stearate.

Examples of the titanium coupling agent for hydrophobizing include tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, and bis (dioctyl pyrophosphate) oxyacetate titanate. . Further, as the silane coupling agent, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N
-Vinylbenzylaminoethyl) γ-aminopropyltrimethoxysilane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane,
Isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, p-methylphenyltrimethoxysilane and the like.

The fatty acids and metal salts thereof include undecylic acid, lauric acid, tridecylic acid, dodecylic acid, myristic acid, palmitic acid, pentadecylic acid, stearic acid, heptadecylic acid, arachiic acid, montanic acid, oleic acid, linoleic acid Long-chain fatty acids such as acid and arachidonic acid are exemplified, and examples of the metal salt include salts with metals such as zinc, iron, magnesium, aluminum, calcium, sodium, and lithium.

Further, examples of the silicone oil include dimethyl silicone oil, methylphenyl silicone oil, amino-modified silicone oil and the like.

These compounds are preferably coated by adding 1 to 10% by weight to the inorganic fine particles, and preferably 3 to 7% by weight. Further, these materials can be used in combination.

The surface can be treated with a polysiloxane having an ammonium salt as a functional group.

[0035] Examples of the organic fine particles that can be used in the present invention include organic fine particles made of a styrene resin, a styrene / acrylic resin, a polyester resin, a urethane resin, or the like.

The method for producing the organic fine particles used in the present invention and the composition thereof are not particularly limited. Generally, vinyl-based organic fine particles are preferable. This is because it can be easily produced by a production method such as an emulsion polymerization method or a suspension polymerization method.

Specifically, styrene, α-methylstyrene, p-chlorostyrene, 3,4-dichlorostyrene,
p-phenylstyrene, p-ethylstyrene, 2,4-
Styrene or styrene derivatives such as dimethylstyrene, pt-butylstyrene, etc., methyl methacrylate,
Ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, methacrylate derivatives such as 2-ethylhexyl methacrylate, methyl acrylate,
Ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, acrylate derivatives such as 2-ethylhexyl acrylate, ethylene,
Olefins such as propylene and isobutylene, halogenated vinyls such as vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride, and vinylidene fluoride; vinyl esters such as vinyl propionate and vinyl acetate; vinyl methyl ether; vinyl ethyl Vinyl ethers such as ethers, vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone, N-vinyl compounds such as N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, vinyl naphthalene, vinyl pyridine and the like. Vinyl compounds, acrylonitrile, methacrylonitrile, acrylamide, N-butylacrylamide, N, N-dibutylacrylamide, methacrylamide, N-butylmethacrylamide, N-octadecylacrylamide, etc. Is acrylic acid or methacrylic acid derivatives. These vinyl monomers can be used alone or in combination.

The resin fine particles can be produced by an emulsion polymerization method or a suspension polymerization method. The emulsion polymerization method is a method in which the above-mentioned monomer is added to water containing a surfactant and emulsified, followed by polymerization. As the surfactant, sodium dodecylbenzenesulfonate, polyvinyl alcohol, an ethylene oxide adduct, As long as it is used as a surfactant such as sodium alcohol sulfate, it can be used without any particular limitation.

A method of using a reactive emulsifier, a method of polymerizing with a hydrophilic monomer, for example, a persulfate initiator such as vinyl acetate or methyl acrylate, and a method of copolymerizing a water-soluble monomer.
So-called non-emulsion polymerization methods such as a method using a water-soluble resin or oligomer, a method using a decomposable emulsifier, and a method using a cross-linkable emulsifier are also suitable. Examples of the reactive emulsifier include sulfonic acid salts of acrylic acid amide and salts of maleic acid derivatives. The non-emulsion polymerization method is not affected by the residual emulsifier, and is suitable when organic fine particles are used alone.

Polymerization initiators required for synthesizing resin fine particles include peroxides such as benzoyl peroxide and lauryl peroxide, and azo-based polymerization initiators such as azobisisobutyronitrile and azobisisovaleronitrile. Agents. The addition amount of these is preferably 0.1 to 2% by weight based on the monomer. If the amount is less than this, the polymerization reaction may be insufficient and a problem of the residual monomer itself may occur. Further, if the amount is too large, a decomposition product of the polymerization initiator remains and affects the chargeability. Further, since the polymerization reaction is too fast, there is a possibility that the molecular weight becomes small. Further, in an emulsion polymerization method or the like, potassium persulfate, sodium thiosulfate, or the like can be used as a polymerization initiator.

These fine particles having a large particle diameter are preferably used in an amount of 0.1 to 5.0% by weight, more preferably 0.5 to 3.0% by weight, based on the toner. When the amount is less than 0.1% by weight, the effect of the addition is hardly exhibited, and when the amount exceeds 5.0% by weight, the toner is not sufficiently retained on the toner surface, and desorption occurs. Could be

As the external additive, an external additive having a smaller particle diameter than the external additive having a large particle diameter may be used in addition to the external additive having a large particle diameter according to the present invention. In this case, as the external additive having a small particle diameter, one having a number average primary particle diameter of 5 to 40 nm can be used. The material is not particularly limited, and various organic fine particles and inorganic fine particles which can be used in the above-mentioned external additive having a large particle diameter can be used. Preferably, inorganic fine particles are used. In the case where an external additive having a large particle size and a small particle size are used in combination, the present invention achieves the object of the present invention by setting the relationship between the external additive having a large particle size and the particle size of the resin particles within the scope of the present invention. be able to. Further, as a ratio of the external additive having a large particle size and the external additive having a small particle size, a weight ratio of large particle size: small particle size = 1: 0.1 to 2.0 is preferable. It is thought that the effect of the external additive having a small particle diameter can be not only the mere addition of fluidity but also the function of effectively retaining the external additive having a large particle diameter by covering the toner surface. The effect is effectively exhibited within the range of this ratio.

Next, the particle diameter of the toner obtained by fusing according to the present invention is preferably 3 to 9 μm in terms of volume average particle diameter. The volume average particle size of the toner is determined by a Coulter Counter
II, it can be measured using a Coulter Multisizer, SLAD1100 (laser diffraction particle size analyzer manufactured by Shimadzu Corporation) or the like.

In the Coulter Counter TA-II and Coulter Multisizer, the aperture diameter is 100 μm.
2 shows a result of measurement using a particle size distribution in the range of 2.0 to 40 μm using the aperture No. 1.

The shape of the toner obtained by fusing has a shape factor represented by the following equation in the range of 1.3 to 2.2 and a shape factor in the range of 1.5 to 2.0. Is preferably 80% by number or more.

Shape factor = ((maximum diameter / 2) ² × π) / projected area This shape factor is obtained by taking a photograph in which the toner particles are magnified 500 times with a scanning electron microscope, and SCANNING IMAGE ANALYS
Analyze the photographic image using "ER" (manufactured by JEOL Ltd.). At this time, the shape factor of the present invention is measured by using the above formula using 500 toner particles, and the arithmetic average value is defined as the shape factor.

When the shape factor is less than 1.3, the shape becomes round, so that the adhesion of the external additive is reduced and the external additive having a large particle diameter is apt to be detached. It becomes difficult to exhibit the effect of. When the shape factor exceeds 2.2, irregularity increases, so that even when an external additive having a large particle diameter is added, crushing when subjected to stress such as development is effectively prevented. And there is a possibility that fine powder is generated.

Further, when the number of toner particles having a shape factor in the range of 1.5 to 2.0 is 80% by number or more, the distribution of the shape can be made uniform. The existence state can be made uniform, and the effect of the present invention can be exhibited over a long period of time.

The particle size of the resin particles for producing the developing toner particles of the present invention is measured by using an electrophoretic light scattering photometer ELS-800 manufactured by Otsuka Electronics Co., Ltd. using a dispersion of the resin particles. It is the value indicated by the weight average particle size. In the present invention, it is 50 to 2000 nm, preferably 80 to 500 nm.

Next, the materials, requirements, devices and the like used in the present invention will be further described.

The toner used in the present invention is a toner obtained by fusing resin particles in an aqueous medium.

The toner used in the present invention may be produced by fusing resin particles containing a colorant in an aqueous medium. From the viewpoint of the problems described above and the viewpoint of stabilization in toner production, a toner in which resin particles, colorant particles, and release agent particles are fused in an aqueous medium is more preferable. Since the toner has a shape having irregularities on the surface from the time of toner production, and furthermore, since the toner is fused in an aqueous medium, there is little difference in the shape and surface properties between the particles. Is sharp, and a finished image excellent in resolution with less toner scattering can be obtained. As described above, this will greatly contribute to the effect of the present invention.

As a method for fusing in an aqueous medium, for example, JP-A-63-186253 and JP-A-63-2827
No. 49, JP-A-7-146583, and the like, and a method of salting out / fusing resin particles to form the resin particles.

The resin particles used in the production of the toner of the present invention may be formed by any of the granulation polymerization methods such as emulsion polymerization, suspension polymerization and seed polymerization, but the emulsion polymerization method is most preferably used in the present invention. .

Hereinafter, examples of the material of the resin particles and the method of production will be described.

<< Materials >> [Monomer] As the polymerizable monomer, a radical polymerizable monomer is an essential component, and a crosslinking agent can be used if necessary. Further, it is preferable to contain at least one radical polymerizable monomer having an acidic group or a radical polymerizable monomer having a basic group described below.

(1) Radical polymerizable monomer The radical polymerizable monomer component is not particularly limited, and a conventionally known radical polymerizable monomer can be used. Also, to satisfy the required characteristics,
Species or a combination of two or more can be used.

Specifically, aromatic vinyl monomers, (meth) acrylate monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers, diolefin monomers Monomers, halogenated olefin monomers and the like can be used.

As the aromatic vinyl monomer, for example,
Styrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n- Styrene-based monomers such as octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, 2,4-dimethylstyrene, and 3,4-dichlorostyrene, and derivatives thereof. .

Examples of the (meth) acrylate-based monomers include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, and ethyl methacrylate. Butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and the like.

Examples of the vinyl ester monomer include vinyl acetate, vinyl propionate, vinyl benzoate and the like.

Examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether and the like.

Examples of the monoolefin-based monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene and the like.

Examples of the diolefin-based monomer include butadiene, isoprene, chloroprene and the like.

Examples of the halogenated olefin monomer include:
Vinyl chloride, vinylidene chloride, vinyl bromide and the like.

(2) Crosslinking Agent As the crosslinking agent, a radical polymerizable crosslinking agent may be added in order to improve the properties of the toner. Examples of the radical polymerizable crosslinking agent include divinylbenzene, divinylnaphthalene,
Examples thereof include those having two or more unsaturated bonds such as divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and diallyl phthalate.

(3) Radical polymerizable monomer having an acidic group or radical polymerizable monomer having a basic group Radical polymerizable monomer having an acidic group or radical polymerizable monomer having a basic group For example, an amine compound such as a carboxyl group-containing monomer, a sulfonic acid group-containing monomer, a primary amine, a secondary amine, a tertiary amine, and a quaternary ammonium salt may be used. it can.

Examples of the radical polymerizable monomer having an acidic group include carboxylic acid group-containing monomers such as acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, monobutyl maleate, And monooctyl maleate.

Examples of the sulfonic acid group-containing monomer include styrene sulfonic acid, allyl sulfosuccinic acid, octyl allyl sulfosuccinate and the like.

These may have a structure of an alkali metal salt such as sodium or potassium or an alkaline earth metal salt such as calcium.

Examples of the radical polymerizable monomer having a basic group include amine compounds, such as dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, and quaternary of the above four compounds. Ammonium salt, 3-dimethylaminophenyl acrylate, 2-hydroxy-3-methacryloxypropyltrimethylammonium salt, acrylamide, N-butylacrylamide, N, N-dibutylacrylamide,
Piperidylacrylamide, methacrylamide, N-butylmethacrylamide, N-octadecylacrylamide; vinylpyridine, vinylpyrrolidone; vinyl N-methylpyridinium chloride, vinyl N-ethylpyridinium chloride, N, N-diallylmethylammonium chloride, N, N- Diallylethylammonium chloride and the like can be mentioned.

As the radical polymerizable monomer used in the present invention, a radical polymerizable monomer having an acidic group or a radical polymerizable monomer having a basic group is used in an amount of 0.1 to 15% of the whole monomer. Preferably, the radical polymerizable cross-linking agent is used in the range of 0.1 to 10% by weight, based on the total radical polymerizable monomer, depending on its properties.

[Chain transfer agent] For the purpose of adjusting the molecular weight, a commonly used chain transfer agent can be used.

The chain transfer agent is not particularly restricted but includes, for example, mercaptans such as octyl mercaptan, dodecyl mercaptan and tert-dodecyl mercaptan, and styrene dimers.

[Polymerization Initiator] The radical polymerization initiator used in the present invention can be appropriately used as long as it is water-soluble.
For example, persulfates (potassium persulfate, ammonium persulfate, etc.), azo compounds (4,4'-azobis-4-cyanovaleric acid and its salts, 2,2'-azobis (2-amidinopropane) salts, etc.), peroxides And the like.

Further, the above radical polymerization initiator can be used as a redox initiator in combination with a reducing agent if necessary. By using a redox-based initiator, the polymerization activity is increased, the polymerization temperature can be reduced, and a further reduction in the polymerization time can be expected.

As the polymerization temperature, any temperature may be selected as long as it is equal to or higher than the lowest radical generation temperature of the polymerization initiator, but for example, a range of 50 ° C. to 90 ° C. is used. However, by using a polymerization initiator started at room temperature, for example, a combination of hydrogen peroxide and a reducing agent (such as ascorbic acid), polymerization can be performed at room temperature or higher.

[Surfactant] In order to carry out emulsion polymerization using the above-mentioned radical polymerizable monomer, it is necessary to carry out emulsion polymerization using a surfactant. The surfactant that can be used at this time is not particularly limited, but the following ionic surfactants can be mentioned as preferred examples.

Examples of the ionic surfactant include sulfonates (sodium dodecylbenzenesulfonate, sodium arylalkyl polyethersulfonate, 3,3-
Sodium disulfonediphenylurea-4,4-diazo-bis-amino-8-naphthol-6-sulfonate, ortho-carboxybenzene-azo-dimethylaniline,
2,2,5,5-tetramethyl-triphenylmethane-
4,4-diazo-bis-β-naphthol-6-sulfonate, etc.), sulfates (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.), fatty acid salts (sodium oleate, laurin) Sodium, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium oleate, etc.).

Further, a nonionic surfactant can also be used. Specifically, polyethylene oxide, polypropylene oxide, a combination of polypropylene oxide and polyethylene oxide, an ester of polyethylene glycol and higher fatty acid, an alkylphenol polyethylene oxide, an ester of higher fatty acid and polyethylene glycol, an ester of higher fatty acid and polypropylene oxide, a sorbitan ester Etc. can be given.

In the present invention, these are mainly used as emulsifiers at the time of emulsion polymerization, but they may be used in other steps or for other purposes.

[Colorant] Examples of the colorant include inorganic pigments and organic pigments.

Conventionally known inorganic pigments can be used. Specific inorganic pigments are exemplified below.

Examples of black pigments include furnace black, channel black, acetylene black,
Carbon black such as thermal black and lamp black, and magnetic powder such as magnetite and ferrite are also used.

These inorganic pigments can be used alone or in combination of two or more as desired. The amount of the pigment to be added is 2 to 20% by weight, preferably 3 to 15% by weight, based on the polymer.

When used as a magnetic toner, the above-mentioned magnetite can be added. In this case, from the viewpoint of imparting predetermined magnetic characteristics, 20 to 6
It is preferable to add 0% by weight.

Conventionally known organic pigments can also be used. Specific organic pigments are exemplified below.

As pigments for magenta or red,
C. I. Pigment Red 2, C.I. I. Pigment Red 3, C.I. I. Pigment Red 5, C.I. I. Pigment Red 6, C.I. I. Pigment Red 7, C.I. I. Pigment Red 15, C.I. I. Pigment Red 16,
C. I. Pigment Red 48: 1, C.I. I. Pigment Red 53: 1, C.I. I. Pigment Red 57:
1, C.I. I. Pigment Red 122, C.I. I. Pigment Red 123, C.I. I. Pigment Red 139,
C. I. Pigment red 144, C.I. I. Pigment Red 149, C.I. I. Pigment Red 166, C.I.
I. Pigment Red 177, C.I. I. Pigment Red 178, C.I. I. Pigment Red 222 and the like.

Examples of orange or yellow pigments include C.I. I. Pigment Orange 31, C.I. I. Pigment Orange 43, C.I. I. Pigment Yellow 12,
C. I. Pigment Yellow 13, C.I. I. Pigment Yellow 14, C.I. I. Pigment Yellow 15, C.I.
I. Pigment Yellow 17, C.I. I. Pigment Yellow 93, C.I. I. Pigment Yellow 94, C.I. I.
Pigment Yellow 138 and the like.

The pigments for green or cyan include:
C. I. Pigment Blue 15, C.I. I. Pigment Blue 15: 2, C.I. I. Pigment Blue 15: 3,
C. I. Pigment Blue 16, C.I. I. Pigment Blue 60, C.I. I. Pigment Green 7 and the like.

These organic pigments can be used alone or in combination of two or more as desired. The amount of the pigment to be added is 2 to 20% by weight, preferably 3 to 15% by weight, based on the polymer.

The colorant can be used after surface modification. As the surface modifier, a conventionally known one can be used, and specifically, a silane coupling agent, a titanium coupling agent, an aluminum coupling agent and the like can be preferably used.

<< Manufacturing Step >> The manufacturing step of the polymerized toner of the present invention includes a polymerization step of preparing resin particles by emulsion polymerization, a step of fusing resin particles in an aqueous medium using the resin particle dispersion, and A washing step of filtering the obtained particles from an aqueous medium to remove a surfactant, a step of drying the obtained particles, and an external additive adding step of adding an external additive and the like to the particles obtained by further drying Etc. Here, the resin particles may be colored particles. In addition, non-colored particles can also be used as resin particles.In this case, color particles are obtained by adding a colorant particle dispersion or the like to a dispersion of resin particles and then fusing the dispersion in an aqueous medium. Can be.

[0094] In particular, as a fusion method, a method of performing salting out using resin particles produced in the polymerization step and performing fusion is preferable. When non-colored resin particles are used, the resin particles and the colorant particles can be salted out and fused in an aqueous medium.

Further, not only the colorant and the release agent, but also a charge control agent or the like, which is a component of the toner, can be added as particles in this step.

[0096] Here, the aqueous medium is composed of water as a main component and has a water content of 50% by weight or more. Examples of the solvent other than water include an organic solvent soluble in water, such as methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran. Particularly preferred are alcoholic organic solvents such as methanol, ethanol, isopropanol and butanol.

The colorant itself may be used after surface modification. The colorant surface modification method is to disperse the colorant in a solvent,
After the addition of the surface modifier, the temperature is raised and the reaction is carried out. After completion of the reaction, the mixture is filtered, washed and filtered repeatedly with the same solvent, and dried to obtain a pigment treated with a surface modifier.

The colorant particles may be prepared by dispersing the colorant in an aqueous medium. This dispersion is performed in a state where the surfactant concentration in water is equal to or higher than the critical micelle concentration (CMC).

The disperser for dispersing the pigment is not particularly limited, but is preferably an ultrasonic disperser, a mechanical homogenizer,
Examples thereof include a pressure disperser such as Menton Gorin and a pressure homogenizer, and a medium disperser such as a sand grinder, a Getzman mill and a diamond fine mill.

As the surfactant used here, the above-mentioned surfactants can be used.

In the step of salting out / fusing, a salting out agent comprising an alkali metal salt or an alkaline earth metal salt is dissolved in water in which resin particles and colorant particles are present. And then heating to above the glass transition point of the resin particles to promote salting out and simultaneously fuse. In this step, a method may be used in which an organic solvent that is infinitely soluble in water is added, and the glass transition temperature of the resin particles is substantially lowered to effectively perform fusion.

Here, the alkali metal salt and the alkaline earth metal salt as salting-out agents include lithium, potassium, sodium and the like as alkali metals, and magnesium, calcium, strontium, barium and the like as alkaline earth metals. And preferably potassium, sodium, magnesium, calcium and barium. Examples of the salt include chloride, bromide, iodine, carbonate, sulfate and the like.

Further, the organic solvent infinitely soluble in water includes methanol, ethanol, 1-propanol,
2-propanol, ethylene glycol, glycerin,
Acetone and the like can be mentioned, and alcohols of methanol, ethanol, 1-propanol and 2-propanol having 3 or less carbon atoms are preferable, and 2-propanol is particularly preferable.

When the fusion of the present invention is carried out by salting out / fusing, it is preferable to minimize the time of standing after adding the salting out agent. Although the reason for this is not clear, the aggregation state of the particles fluctuates depending on the standing time after salting out,
There are problems that the particle size distribution becomes unstable and the surface properties of the fused toner fluctuate. The temperature at which the salting-out agent is added must be at least equal to or lower than the glass transition temperature of the resin particles. The reason for this is that if the temperature at which the salting-out agent is added is higher than the glass transition temperature of the resin particles, the salting-out / fusion of the resin particles proceeds rapidly, but the particle size cannot be controlled, and There is a problem that particles having a particle size are generated. The range of the addition temperature may be lower than the glass transition temperature of the resin, but is generally 5 ° C to 55 ° C, preferably 10 ° C to 45 ° C.

In the present invention, it is preferable to use a method in which a salting-out agent is added at a temperature equal to or lower than the glass transition temperature of the resin particles, and thereafter, the temperature is raised as quickly as possible and heated to a temperature equal to or higher than the glass transition temperature of the resin particles. The time until the temperature rise is preferably less than 1 hour. Further, it is necessary to raise the temperature promptly, but the rate of temperature increase is preferably 0.25 ° C./min or more. The upper limit is not particularly clear, but if the temperature is raised instantaneously, salting out proceeds rapidly, and there is a problem that particle size control is difficult to perform.

[Tonerization Step] In the tonerization step, the toner particles obtained above may be used as they are, but for the purpose of improving fluidity, charging property and cleaning property, for example, An agent may be added. As a method of adding the external additive, various known mixing devices such as a Turbula mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer can be used.

The toner may contain a material capable of imparting various functions as a toner material, in addition to the colorant and the release agent. Specific examples include a charge control agent. These components are added at the stage of emulsion polymerization of the resin particles, the dispersion is added, the resin particles and the colorant particles are added at the same time in the salting-out / fusion step, and the toner particles are included in the toner. It can be added by various methods such as a method of adding it to an aqueous solution. As a preferable method, a method in which the charge control agent particles and / or the fixability improving agent particles are added in a dispersion state at the stage of the emulsion polymerization of the resin particles, and the above-described salting out /
In the fusing step, a method in which the charge control agent particles and / or the fixability improving agent particles are added together with the resin particles and the colorant particles in the form of a dispersion and then salted out / fused is used.

As the release agent, it is preferable to use various known ones which can be dispersed in water. Specifically, olefinic waxes such as polypropylene and polyethylene, modified products thereof, natural waxes such as carnauba wax and rice wax,
An amide wax such as a fatty acid bisamide can be used. It has already been mentioned that these are preferably added as release agent particles and are preferably salted out / fused together with the resin or colorant.

Similarly, various charge control agents are also known.
What can be dispersed in water can also be used. Specifically, nigrosine dyes, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines,
Quaternary ammonium salt compounds, azo-based metal complexes, salicylic acid metal salts or metal complexes thereof.

The particles of the release agent and the charge control agent preferably have a number average primary particle diameter of about 10 to 500 nm in a dispersed state.

<< Developer >> The toner used in the present invention is as follows.
Although it may be used as a one-component developer or a two-component developer,
Preferably as a two-component developer.

When the toner is used as a one-component developer, there is a method in which the toner is used as it is as a non-magnetic one-component developer. However, usually, magnetic particles having a particle size of about 0.1 to 5 μm are contained in toner particles. Used as a developer. As a method of containing the same, it is common to make the non-spherical particles contain the same as the coloring agent.

Further, it can be used as a two-component developer by mixing with a carrier. In this case, as the magnetic particles of the carrier, conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead are used. Particularly, ferrite particles are preferable. The magnetic particles have a volume average particle size of 15
-100 μm, more preferably 25-60 μm.

The volume average particle size of the carrier is typically measured by a laser diffraction type particle size distribution analyzer “HELOS” equipped with a wet disperser (SYMPATIC (SYMPIC)).
(ATEC)).

The carrier is preferably a carrier in which magnetic particles are further coated with a resin, or a so-called resin-dispersed carrier in which magnetic particles are dispersed in a resin. Although there is no particular limitation on the resin composition for coating, for example, an olefin resin, a styrene resin, a styrene / acrylic resin, a silicone resin, an ester resin, a fluorine-containing polymer resin, or the like is used. The resin for constituting the resin-dispersed carrier is not particularly limited, and a known resin can be used. For example, styrene / acrylic resin, polyester resin, fluororesin, phenol resin, or the like can be used. Can be.

<< Image Forming Method >> Next, an image forming method or apparatus of the present invention will be described.

FIG. 1 is a schematic structural view of the image forming apparatus of the present invention. Reference numeral 4 denotes a photoconductor drum, which is formed by forming an organic photoconductor (OPC) as a photoconductor layer on the outer peripheral surface of a drum substrate made of aluminum, and rotates at a predetermined speed in a direction indicated by an arrow. In the embodiment, the photosensitive drum 4 has an outer diameter of 60 mm.

In FIG. 1, exposure light is emitted from the semiconductor laser light source 1 based on information read by a document reading device (not shown). This is distributed by a polygon mirror 2 in the direction perpendicular to the plane of the paper of FIG. 1, and is radiated on the photoreceptor surface via an fθ lens 3 for correcting image distortion to form an electrostatic latent image. The photoreceptor drum is uniformly charged in advance by the charger 5 and starts rotating clockwise in synchronization with the image exposure timing.

The electrostatic latent image on the surface of the photoreceptor is developed by the developing device 6, and the formed developed image is transferred to the recording material 8 conveyed at a proper timing by the operation of the transfer device 7. Further, the photosensitive drum 4 and the recording material 8 are separated by a separator (separation pole) 9, and the toner developed image is transferred and carried on the recording material 8, guided to a fixing device 10 and fixed.

The untransferred toner remaining on the photoreceptor surface is
It is cleaned by a cleaning device 11 of a cleaning blade type, and the remaining charge is removed by a pre-charging exposure (PCL) 12, and is uniformly charged again by the charger 5 for the next image formation.

The recording material is typically plain paper.
There is no particular limitation as long as an unfixed image after development can be transferred, and a PET base for OHP and the like are of course included.

The cleaning blade 13 has a thickness of 1 mm.
A rubber-like elastic body of about 30 mm is used, and urethane rubber is most often used as a material. Since this is used while being pressed against the photoconductor, heat is easily transmitted, and it is desirable to keep the photoconductor away from the photoconductor when the image forming operation is not performed.

In recent years, in the field of electrophotography and the like in which an electrostatic latent image is formed on a photoreceptor and this latent image is developed to obtain a visible image, it is easy to improve image quality, convert, edit, etc., and obtain a high quality image. Research and development of an image forming method employing a digital method capable of forming are being actively conducted.

As a scanning optical system that modulates light with a digital image signal from a computer or a copy original used in the image forming method and apparatus, an acousto-optic modulator is interposed in a laser optical system, and the acousto-optic modulator uses the acousto-optic modulator. There are a device for modulating the light and a device for directly modulating the laser intensity using a semiconductor laser. A dot-like image is formed by spot exposure on a uniformly charged photoconductor from these scanning optical systems.

The beam emitted from the above-described scanning optical system has a round or elliptical luminance distribution approximating a normal distribution with a skirt spreading left and right. One or both of the scanning direction and the sub-scanning direction has a very small circular or elliptical shape of 20 to 100 μm.

The image forming apparatus includes the photosensitive drum 4
And a process cartridge including at least one of the charger 5, the developing device 6, the cleaning device 11, the transfer device 7, and the like.

When the toner of the present invention is applied to a color image forming method, a method of forming a single color image on a photoreceptor and sequentially transferring it to a recording material (this is referred to as a sequential transfer method and is shown in FIG. 2), or A method of developing a single-color image on a photoreceptor a plurality of times to form a color image and then transferring the color image to a recording material at a time (this method is referred to as a collective transfer method and shown in FIG. 3) is exemplified.

Here, 4 is a photosensitive drum, 5 is a charger, 6 is a developing device (developing unit), 11 is a cleaning device, 15 is a transfer drum, 16 is a transport unit, 17 is a suction electrode, and 18 is a suction electrode. Transfer pole, 19 is peeling pole, 20
Denotes a removal electrode, and 21 denotes a transport unit.

As the developer carrier used in the present invention, a developing device having a magnet built in the carrier is used, and the surface of the developer carrier is made of aluminum or oxidized surface. Aluminum or stainless steel is used.

The toner image formed on the photoreceptor by the various methods described above is transferred to a transfer material such as paper in a transfer step. The transfer method is not particularly limited, and various methods such as a so-called corona transfer method and a roller transfer method can be adopted.

[0131]

Next, embodiments of the present invention will be specifically described, but the present invention is not limited to these embodiments. In the description, “parts” means “parts by weight”.

Example 1 Adeka Hope LS-90 (sodium n-dodecyl sulfate manufactured by Asahi Denka Co., Ltd.) was placed in a resin container having an inner volume of 20 L (liter).
And 0.9 L of pure water and 10.0 L of pure water are added and stirred and dissolved.
To this solution, 1.20 kg of Regal 330R (carbon black manufactured by Cabot Corporation) is gradually added with stirring, and the mixture is stirred well for 1 hour after the addition. Next, continuous dispersion was performed for 20 hours using a sand grinder (medium type disperser).

After the dispersion, the particle diameter of the dispersion was measured using an electrophoretic light scattering photometer ELS-800 manufactured by Otsuka Electronics Co., Ltd., and as a result, the weight average diameter was 122 nm. Further, the solid content concentration of the above dispersion measured by a weight method by standing drying was 16.6% by weight. This dispersion is referred to as “colorant dispersion 1”.

In a 10 L stainless steel pot, add 0.055 sodium dodecylbenzenesulfonate (manufactured by Kanto Chemical Co., Ltd.)
Then, add 4.0 L of ion-exchanged water and stir and dissolve at room temperature. This is designated as an anionic surfactant solution A.

In a 10 L stainless steel pot, 0.014 kg of Newcol 565C (manufactured by Nippon Emulsifier) is added, 4.0 L of ion-exchanged water is added, and the mixture is stirred and dissolved at room temperature. This is designated as nonionic surfactant solution B.

223.8 g of potassium persulfate (manufactured by Kanto Kagaku) was placed in a 20 L enamel pot, and ion-exchanged water 1 was added.
Add 2.0 L and stir and dissolve at room temperature. This is called initiator solution C.

A 100 L GL (glass lining) reactor equipped with a temperature sensor, a cooling pipe, and a nitrogen introducing device was charged with W.
3.41 kg of the AX emulsion (polypropylene emulsion having a number average molecular weight of 3000: number average primary particle diameter = 120 nm / solid content = 29.9%), an anionic surfactant solution A and a nonionic surfactant solution B are added and stirred. To start. Next, 44.0 L of ion-exchanged water is added.

When heating is started and the liquid temperature reaches 75 ° C., an initiator solution C is added. Thereafter, the liquid temperature is reduced to 75
While controlling the temperature at ± 1 ° C., 12.1 kg of styrene, 2.88 kg of n-butyl acrylate, and 1.04 kg of methacrylic acid
kg and 548 g of t-dodecyl mercaptan.

The temperature of the solution was further raised to 80 ° C. ± 1 ° C.
Heating and stirring were performed for hours.

The liquid temperature is cooled to 40 ° C. or less, and the stirring is stopped. The mixture was filtered through a pole filter and the latex was filtered.
A.

The glass transition temperature of the resin particles in latex-A is 57 ° C., the softening point is 121 ° C., and the molecular weight distribution is as follows: weight average molecular weight = 12.7 million, weight average particle size is 12
It was 0 nm.

In a new 10 L stainless steel pot, add sodium dodecylbenzenesulfonate (Kanto Chemical Co., Ltd.)
55 kg is added, 4.0 L of ion-exchanged pure water is added, and the mixture is stirred and dissolved at room temperature. This is designated as an anionic surfactant solution D.

In a 10 L stainless steel pot, 0.14 kg of Newcol 565C (manufactured by Nippon Emulsifier) is added, and 4.0 L of ion-exchanged pure water is added, followed by stirring at room temperature for dissolution. This is designated as a nonionic surfactant solution E.

200.7 g of potassium persulfate (manufactured by Kanto Chemical Co., Ltd.) was placed in a 20 L enamel pot, and deionized water 1
Add 2.0 l and stir and dissolve at room temperature. This is designated as an initiator solution F.

A WAX emulsion (polypropylene emulsion having a number average molecular weight of 3,000: number average primary particle diameter = 120 nm) was placed in a 100 L GL reactor (a stirring blade was a Faudler blade) equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a comb baffle. / Solids concentration = 29.9%) 3.41
kg, anionic surfactant solution D and nonionic surfactant solution E are added, and stirring is started. Next, 44.0 L of ion-exchanged water is charged.

When heating is started and the liquid temperature reaches 70 ° C., an initiator solution F is added. At this time, styrene 1
1.0 kg, 4.00 kg of n-butyl acrylate, 1.04 kg of methacrylic acid, and t-dodecyl mercaptan 9.
And a solution obtained by previously mixing 02 g with the mixture.

Thereafter, the mixture was heated and stirred for 6 hours while controlling the liquid temperature at 72 ° C. ± 2 ° C. In addition, liquid temperature is 80 ℃ ± 2 ℃
And heated and stirred for 12 hours.

The temperature of the solution is cooled to 40 ° C. or less, and the stirring is stopped. The solution was filtered through a Pall filter, and this filtrate was used as Latex-B.

The glass transition temperature of the resin particles in Latex-B was 58 ° C., the softening point was 132 ° C., and the molecular weight distribution was weight average molecular weight = 245,000 and weight average particle diameter was 12
It was 0 nm.

In a 35 L stainless steel pot, 5.36 kg of sodium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) as a salting-out agent and 20.0 L of ion-exchanged water are stirred and dissolved. This is designated as sodium chloride solution G.

FC-170C in a 2L glass beaker
(Sumitomo 3M nonionic surfactant) 1.00
g, add 1.00 L of ion-exchanged water and stir to dissolve. This is designated as nonionic surfactant solution H.

The latex-A prepared above was placed in a 100 L SUS reaction vessel equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a comb baffle (the stirring blade was an anchor blade).
0.0 kg, 5.2 kg of Latex-B, 0.4 kg of Colorant Dispersion 1 and 20.0 kg of ion-exchanged water are added and stirred. Then, the mixture was heated to 40 ° C., and sodium chloride solution G and isopropanol (manufactured by Kanto Chemical Co., Ltd.) 6.00 k
g, Nonionic surfactant solution H are added in this order. Then, after leaving it for 10 minutes, the temperature was started and the liquid temperature was 8
The temperature is raised to 5 ° C. in 60 minutes. At a liquid temperature of 85 ° C ± 2 ° C,
Heat and stir for 6 hours for salting out / fusion. Thereafter, the mixture is cooled to 40 ° C. or less and the stirring is stopped. The solution is filtered through a sieve having an opening of 45 μm, and this filtrate is used as an association liquid.

Next, the non-spherical particles in the form of a wet cake were collected by filtration from the association liquid using a nutche. Thereafter, the substrate was washed with ion-exchanged water.

The wet cake-like non-spherical particles having been washed as described above are taken out from the nutsche, and all paper bat 5
I spread it while crushing it into pieces. After covering with kraft paper, it was dried with a blow dryer at 40 ° C. for 100 hours.

[0155] The block-shaped non-spherical particles that had been dried were crushed by a Henschel pulverizer.

The non-spherical particles obtained as described above are referred to as “non-spherical particles 1”.

Example 2 In the anionic surfactant solution A of Example 1, the addition amount of sodium dodecylbenzenesulfonate was 0.03
Non-spherical particles of the present invention were obtained in the same manner except that the amount of Newcol 565C in the nonionic surfactant solution B was 0.007 kg.

This is referred to as “non-spherical particles 2”.

Example 3 In the anionic surfactant solution A of Example 1, the addition amount of sodium dodecylbenzenesulfonate was 0.01
Non-spherical particles of the present invention were obtained in the same manner except that the amount of Newcol 565C in the nonionic surfactant solution B was 0.0035 kg.

This is referred to as “non-spherical particles 3”.

Example 4 "Non-spherical particles 4" were obtained in the same manner as in Example 1 except that the temperature at the time of association was set to 95 ° C. and the association time was set to 7 hours.

Example 5 "Non-spherical particles 5" were obtained in the same manner as in Example 1 except that the association time during the association was changed to 4 hours.

Example 6 "Non-spherical particles 6" were obtained in the same manner as in Example 1 except that the temperature during the association was changed to 75 ° C.

Example 7 The following components were added to a 100-L GL reactor equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a comb baffle (the stirring blade was a Faudler blade).

Styrene 60 parts Butyl acrylate 40 parts Acrylic acid 8 parts Water 100 parts Nonionic emulsifier (Emulgen 950) 1 part Anionic emulsifier (Neogen R) 1.5 parts Potassium persulfate 0.5 part The above aqueous mixture is stirred 70 Polymerization was conducted at 8 ° C. for 8 hours to obtain an acidic polar group-containing resin emulsion (latex 4) having a solid content of 50%. The weight average particle size of the resin particles in the latex is 150 nm.

Toner Preparation Latex 4 120 parts Carbon black (Legal 330R) 5 parts Chromium dye (Bontron-E81) 1 part Water 200 parts
C. for 2 hours. Then, with further stirring, 70 ° C
And kept for 3 hours. The liquid dispersion obtained by cooling was subjected to Buchner filtration, washed with water, and vacuum dried at 50 ° C. for 10 hours to obtain non-spherical particles.

This is referred to as “non-spherical particles 7”.

Table 1 below shows the above non-spherical particles 1 to 3 and 7
The following shows the weight average particle size of the resin particles used in the preparation of Example 1.

[0169]

[Table 1]

Comparative Example 1 165 g of styrene, 35 g of n-butyl acrylate, 10 g of phthalocyanine blue, 2 g of metal di-t-butylsalicylate, styrene / methacrylic acid copolymer 8
g, paraffin wax (mp = 70 ° C.) 20 g 60
C. and uniformly dissolved and dispersed at 12000 rpm with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). 10 g of 2,2'-azobis (2,4-valeronitrile) was added thereto as a polymerization initiator. Was added and dissolved to prepare a polymerizable monomer composition. Then, 0.10 g of ion-exchanged water was added to 710 g.
450 g of M sodium phosphate aqueous solution was added, and 68 g of 1.0 M calcium chloride was gradually added while stirring at 12,000 rpm with a TK homomixer to prepare a suspension in which tricalcium phosphate was dispersed.

The polymerizable monomer composition was added to the suspension, and the mixture was stirred with a TK homomixer at 10,000 rpm for 20 minutes to granulate the polymerizable monomer composition. Then 8
The reaction was performed at 0 ° C. for 10 hours. Tricalcium phosphate was dissolved and removed with hydrochloric acid, followed by filtration, washing and drying to obtain colored particles having a volume average particle size of 7.9 μm. This is designated as “Comparative Particle 1”.

Comparative Example 2 100 parts of styrene / acrylic resin, carbon black 1
0 parts, low molecular weight polypropylene (number average molecular weight = 300
0) 4 parts were melted, kneaded and pulverized to have a volume average particle size of 6.
9 μm colored particles were obtained. This is called “Comparative Particle 2”
And

(Evaluation) First, the volume average particle size and shape factor of the non-spherical particles will be described.

[0174]

[Table 2]

External additives shown in the following Tables 3 and 4 were added to the non-spherical particles.

[0176]

[Table 3]

[0177]

[Table 4]

• Silica A: hexamethyldisilazane treatment (number average primary particle diameter = 150 nm) • Silica B: hexamethyldisilazane treatment (number average primary particle diameter = 250 nm) • Titanium oxide A: hexyltrimethoxysilane treatment (・ Titanium oxide B: octyltrimethoxysilane treatment (number average primary particle diameter = 250 nm) ・ Strontium titanate A: number average primary particle diameter = 36
0 nm ・ Strontium titanate B: number average primary particle diameter = 85
0 nm P-MMA (organic fine particles A): number average primary particle size = 1
200 nm P-MMA (organic fine particles B): number average primary particle diameter = 6
00 nm ・ Silica C: Hexamethyldisilazane treatment (number-average primary particle diameter = 10 nm) ・ Silica D: dichlorodimethylsilane treatment (number-average primary particle diameter = 17 nm) Also, the volume average of these toner and styrene / acrylic resin coating A developer having a toner concentration of 6% was prepared by mixing a ferrite carrier having a particle size of 45 μm and used for printing evaluation. These developers are referred to as “developer 1 for the present invention” to “developer 14 for the present invention” corresponding to the toner, respectively.
"Comparative developer 1" to "Comparative developer 3".

Evaluation (Contact Development Method) Using a digital copying machine Konica 7033 manufactured by Konica Corporation, the copying speed was further modified to A4 and 30 sheets / min, and the actual copying evaluation was performed. The conditions are as shown below. A laminated organic photoreceptor was used as the photoreceptor.

(Photoconductor) As a photoconductor, a photoconductor for a Konica 7033 digital copying machine manufactured by Konica Corporation (diameter = 60)
mm, an intermediate layer, a charge generation layer, and a charge transport layer on an aluminum support (substrate).

The structure of the photoreceptor is shown below.

Subtraction: Titanium chelate compound TC-750
(Matsumoto Pharmaceutical Co., Ltd.) / Silane coupling agent KBM503
(Shin-Etsu Chemical Co., Ltd.) = 2 / 1.3 propanol solution was applied. The dry film thickness was 1.0 μm.

Charge generation layer: titanyl phthalocyanine / silicone modified butyral (KR5254 manufactured by Shin-Etsu Chemical) =
At a ratio of 1/1, the dry film thickness was 0.3 μm.

Charge transporting layer: Dry film thickness was 28 μm at a ratio of α-phenylstilbene type charge transporting material / polycarbonate Z = 2/3.

Developing conditions DC bias; -500 V Dsd (distance between photoconductor and developing sleeve); 600 μm Developer layer regulation: Magnetic H-Cut system Developer layer thickness: 700 μm Developing sleeve diameter: 40 mm Also remaining on the photoconductor The untransferred toner has a thickness of 3.0 mm
A cleaning method using a urethane rubber blade was adopted.

As the recording material to be used, plain paper having a continuous weight of 55 kg was used, and an image was formed in the vertical direction. The image forming conditions include a low-temperature and low-humidity environment (10 ° C., 15% RH).
Printing evaluation was performed using the above-mentioned developer under two kinds of environmental conditions of high temperature and high humidity environment (30 ° C., 80% RH). The printing was performed using pixels having a low pixel ratio of 2%, and the printing was paused for each sheet in the intermittent mode to print 50,000 sheets in total. The printing quality of the 50,000 images was compared. Further, the presence or absence of an image defect was visually determined for the image after 50,000 sheets.

The criteria are as follows.

Rank A: No image defect Rank B: Less than 5 black spots of 0.5 mm or less in solid white image Rank C: 5 or more black spots of 0.5 mm or less in solid white image Rank D: Black spots larger than 0.5mm are 5 in solid white image
For image quality evaluation, image density and fog density were compared. The maximum image density was compared using absolute reflection density using RD-918 manufactured by Macbeth. Fog was compared by relative reflection density where the density of paper was "0".

The results are shown below.

[0190]

[Table 5]

[0191]

[Table 6]

Developers in the present invention (Developers 1 to 1 for the present invention)
It can be seen that each of the samples using 4) retains good characteristics even after forming 50,000 sheets of images.

[0193]

According to the present invention, there is provided a toner for developing an electrostatic latent image capable of forming a stable image without lowering of the maximum density, generation of fog, and occurrence of image defects even when used for a long period of time. An image forming method and an image forming apparatus using the same can be provided.

[Brief description of the drawings]

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

FIG. 2 is a schematic configuration diagram of a sequential transfer system to which the present invention can be applied.

FIG. 3 is a schematic configuration diagram of a batch transfer method to which the present invention can be applied.

DESCRIPTION OF SYMBOLS 1 Semiconductor laser light source 2 Polygon mirror 3 fθ lens 4 Photoconductor drum 5 Charger 6 Developing device 7 Transfer device 8 Recording material 9 Separation pole 10 Fixing device 11 Cleaning device 12 Pre-charge exposure (PCL) 13 Cleaning blade 15 Transfer drum

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Yamada 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation F-term (reference) 2H005 AA08 AA15 AB03 CB07 CB08 CB13 EA05

Claims (8)

[Claims] 1. A toner for developing an electrostatic latent image comprising at least colored particles obtained by fusing resin particles in an aqueous medium and an external additive, the number average primary particle diameter (Anm) of the external additive And a weight average particle size (Bnm) of the resin particles having the following relationship. 0.1 ≦ B / A ≦ 1.0 B = 50-2000 nm 2. The electrostatic latent image developing toner according to claim 1, wherein the external additive is organic fine particles. 3. The toner for developing an electrostatic latent image according to claim 1, wherein the external additive is a titanate compound. 4. The electrostatic latent image developing toner according to claim 1, wherein the external additive is titanium oxide. 5. The toner for developing an electrostatic latent image according to claim 1, wherein the external additive is silica. 6. The toner for developing an electrostatic latent image has a volume average particle diameter of 3 to 9 μm, a shape coefficient of the toner represented by the following formula in a range of 1.3 to 2.2, and The toner for developing an electrostatic latent image according to any one of claims 1 to 5, wherein toner particles having a shape factor in a range of 1.5 to 2.0 are 80% by number or more. Shape factor = ((maximum diameter / 2) ² × π) / projected area 7. An image forming method in which an unfixed toner image formed on a photoreceptor through a process of uniform charging, image exposure and development is transferred to a recording material and post-fixed, wherein at least resin particles are used as a developer. Using a toner for developing an electrostatic latent image composed of colored particles fused in an aqueous medium and an external additive, the number average primary particle diameter (Anm) of the external additive and the weight average particle diameter of the resin particles ( Bnm) having the following relationship. 0.1 ≦ B / A ≦ 1.0 B = 50-2000 nm 8. An image forming apparatus for transferring an unfixed toner image formed on a photoreceptor through steps of uniform charging, image exposure, and development to a recording material and post-fixing the same, wherein at least resin particles are used as a developer. Using a toner for developing an electrostatic latent image composed of colored particles fused in an aqueous medium and an external additive, the number average primary particle diameter (Anm) of the external additive and the weight average particle diameter of the resin particles ( Bnm) having the following relationship. 0.1 ≦ B / A ≦ 1.0 B = 50-2000 nm