JP2001075314A - Fine magnetic particle-dispersed type resin carrier and two component developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fine magnetic particle-dispersed type carrier capable of forming an image high in density and color image precision for a long period and superior in mixability with a toner and charge donation ability to the toner and low in tendency to produce a spent toner. SOLUTION: The fine magnetic particle-dispersed type carrier is formed by composite particles comprising at least fine magnetic particles treated to enhance hydrophilicness and a binder resin, and the fine magnetic particle- dispersed type carrier are characterzed by incorporating a phosphorus compound in an amount of 0.03-5.0 weight % in terms of P to Fe in these fine magnetic particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetic fine particle-dispersed resin carrier and a two-component developer for developing an electrostatic image in electrophotography, electrostatic recording, and the like.

[0002]

2. Description of the Related Art U.S. Pat.
7, 691, JP-B-42-23910 and JP-B-43-24748 describe various methods. These methods form an electrostatic image by irradiating the photoconductive layer of the electrostatic image carrier with a photo image, and then apply toner to the electrostatic image to develop the electrostatic image, After the transfer of the toner image onto a transfer material such as paper, the toner image is fixed by heat, pressure, heat and pressure, or a solvent vapor to obtain a copy or print.

In the step of developing the electrostatic image, a toner image is formed on the frictionally charged toner by utilizing the electrostatic interaction of the electrostatic image. In general, of the methods for developing an electrostatic image using toner, a two-component developer in which toner is mixed with a carrier is suitably used in a full-color copying machine or a printer that requires high image quality.

In this developing method, the carrier imparts an appropriate amount of positive or negative charge to the toner by triboelectric charging, and carries the toner on the surface by the electrostatic attraction of the triboelectric charging.

A developer having a toner and a carrier is coated on a developing sleeve containing a magnet to a predetermined layer thickness by a developer layer thickness regulating member, and by utilizing a magnetic force, an electrostatic image carrier (photosensitive material) is formed. Body) and the developing sleeve are transported to a developing area formed between the developing sleeve and the developing sleeve.

A predetermined developing bias voltage is applied between the photosensitive member and the developing sleeve, and the toner is developed on the photosensitive member in the developing area.

There are various characteristics required for the carrier, and particularly important characteristics include appropriate charging properties, pressure resistance to an applied electric field, impact resistance, abrasion resistance, spent resistance, developability, and the like. Can be

For example, when a developer is used for a long time,
A toner which does not contribute to the development called a spent toner is fused to the surface of the carrier, and toner filming occurs. As a result, the developer is deteriorated and the image quality of the developed image is deteriorated accordingly.

In general, if the true specific gravity of the carrier is too large, the developer may be used when the developer is brought into a predetermined layer thickness on the developing sleeve by the developer layer thickness regulating member, or when the developer is stirred in a developing device. In this case, the load on the developer increases. In the long-term use of the developer, (a) toner filming,
(B) Carrier destruction and (c) toner deterioration are likely to occur. As a result, deterioration of the developer and accompanying image quality deterioration of the developed image are likely to occur.

Further, when the particle size of the carrier is large, the load on the developer is increased similarly to the above, so that the above (a) to (c) tend to occur, and as a result, the deterioration of the developer occurs It will be easier. In addition, (d) the reproducibility of the fine line of the developed image is likely to be reduced.

Therefore, in a carrier in which the above (a) to (c) are likely to occur, it takes time and effort to replace the developer periodically and is uneconomical, so that the load on the developer is reduced. Alternatively, it is preferable to improve the impact resistance and spent resistance of the carrier to prevent the above (a) to (c) and extend the life of the developer.

When the particle size of the carrier is reduced, (e) the carrier easily adheres to the electrostatic image carrier. Further, reducing the particle diameter of the carrier only with a constant toner particle diameter results in (f) the distribution of the charge amount of the toner being broadened, and the toner flies to a non-image portion due to charge-up particularly in a low humidity environment ( Hereinafter, this phenomenon will be referred to as “fog”).

As a carrier for solving the above problems (a) to (f), a magnetic fine particle-dispersed resin carrier can be mentioned. This carrier is relatively easy to be formed into a sphere having a small particle shape distortion and a high particle strength, and is excellent in fluidity. Since the particle size can be controlled in a wide range, it is suitable for a high-speed copying machine in which the number of rotations of a developing sleeve or a magnet in the sleeve is large, a high-speed laser beam printer of a general-purpose computer, and the like.

A magnetic fine particle-dispersed resin carrier has been proposed in JP-A-54-66134 and JP-A-61-9659. However, when the magnetic particle carrier does not contain a large amount of a magnetic substance, the saturation magnetization is small with respect to the particle diameter, carrier adhesion easily occurs on the electrostatic image carrier during development, and the developer Replenishment,
Alternatively, it may be necessary to provide a mechanism for collecting the attached carrier in the image forming apparatus.

In addition, when a magnetic substance is contained in a large amount in a magnetic fine particle-dispersed resin carrier, the impact resistance becomes weak because the amount of the magnetic substance increases with respect to the binder resin, so that the developer is not used. When a predetermined layer thickness is formed on the sleeve by the developer layer thickness regulating member, (g) the magnetic material is easily dropped from the carrier, and as a result, the developer is easily deteriorated.

Further, when the magnetic fine particle-dispersed resin carrier contains a large amount of magnetite, the specific resistance of the carrier decreases due to an increase in the amount of magnetite having a low specific resistance. As a result, (h) Image defects due to the leakage of the bias voltage applied during development are also likely to occur.

Further, when a large amount of a magnetic substance is contained in the above-mentioned magnetic fine particle-dispersed resin carrier, the residual magnetic flux density of the carrier increases, and the fluidity of the developer deteriorates. Therefore, when the toner is consumed by the development and the toner is replenished to the developer, the carrier is likely to be poorly mixed with the toner, or a stable amount of the developer is less likely to be transported and adhered on the developing sleeve. Therefore, stable image density cannot be obtained.

On the other hand, JP-A-58-21750 discloses that
A technique of coating a carrier core with a resin has been proposed.
The carrier coated with the resin can improve spent resistance, impact resistance, and pressure resistance against applied voltage. In addition, since the charging characteristics of the toner can be controlled by the charging characteristics of the resin to be coated, a desired charge can be imparted to the toner by selecting the resin to be coated.

However, even in the above resin-coated carrier, when the amount of the coating resin is large and the specific resistance of the carrier is high, the charge-up phenomenon of the toner easily occurs in a low humidity environment. Further, when the amount of the coating resin is small, the specific resistance of the carrier becomes too low, so that an image defect easily occurs due to a leak of the developing bias voltage.

Further, depending on the coating resin, even if the specific resistance of the carrier coated with the resin is considered to be an appropriate specific resistance in measurement, an image defect is likely to occur due to leakage of the developing bias voltage, or in a low humidity environment. In some cases, the charge-up phenomenon easily occurs.

As described above, it is possible to cope with strict quality demands demanded today, for example, various objects such as fine lines, small letters, photographs and color originals, and furthermore, high image quality, high quality, high speed and high durability. There is a long-awaited demand for a magnetic fine particle-dispersed resin carrier satisfying the following.

[0022]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic fine particle-dispersed resin carrier and a two-component developer which solve the above-mentioned problems.

An object of the present invention is to disperse magnetic fine particles capable of forming a high-quality toner image by preventing the carrier from adhering to the electrostatic image carrier and preventing or suppressing fog because the carrier has a high electric resistance. Another object of the present invention is to provide a mold resin carrier and a two-component developer.

An object of the present invention is to provide a magnetic fine particle-dispersed resin carrier and a two-component developer capable of forming a high-definition color image at a high image density without being affected by temperature and humidity.

An object of the present invention is to provide a magnetic fine particle-dispersed resin carrier which is excellent in durability without image deterioration even when a large number of images are formed, since the carrier has low residual magnetization and high fluidity. Another object of the present invention is to provide a system developer.

[0026]

Specifically, the present invention provides:
A magnetic fine particle-dispersed resin carrier formed of composite particles having at least lipophilic magnetic fine particles and a binder resin, wherein the magnetic fine particles have a P content of 0.03 to 5 with respect to Fe. The present invention relates to a magnetic fine particle-dispersed resin carrier containing 0.0% by weight of a phosphorus compound.

The present invention also relates to a two-component developer having at least a toner having toner particles, an external additive and a magnetic fine particle-dispersed resin carrier, wherein the toner has a weight average particle diameter of 3 to 9 μm, And 40% by weight or less, wherein the carrier is a carrier having the above-mentioned structure.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of various studies and investigations to improve the above-mentioned problems, the present inventors have found that a magnetic fine particle-dispersed resin carrier containing magnetic fine particles containing a specific amount of a phosphorus component and a resin carrier thereof. The inventors have found that a two-component developer is effective in improving various properties, and have reached the present invention.

The magnetic fine particle-dispersed resin carrier (hereinafter referred to as carrier) used in the present invention is composed of composite particles obtained by dispersing specific magnetite particles as magnetic fine particles.

The magnetite particles of the present invention are characterized in that the electric resistance, residual magnetization and fluidity of the carrier are improved in a well-balanced manner by controlling the amount of the phosphorus component contained therein.

That is, a carrier having magnetite particles having a phosphorus content of 0.03 to 5.0% by weight with respect to Fe in terms of P, and having a residual magnetic flux density of 9 Am ² / kg.
Or less, preferably equal to or less than 7Am ² / kg. If the residual magnetic flux density of the carrier is larger than 9 Am ² / kg, the two-component developer causes poor fluidity due to magnetic aggregation.

The magnetite particles according to the present invention can be prepared by heating a ferrous hydroxide obtained by reacting an aqueous solution of a ferrous salt with an alkali hydroxide while passing an oxygen-containing gas while heating the ferrous hydroxide. In producing magnetite particles by oxidizing ferrous iron, magnetite particles characterized by adding a water-soluble phosphorus compound in advance to either an alkali hydroxide or an aqueous ferrous salt solution or the above-mentioned ferrous hydroxide. It is.

As described above, by adding a phosphorus component to the granular magnetite particles used for the carrier, the residual magnetic flux density is reduced within a range that does not impair the magnetic properties to be possessed as the carrier, for example, the saturation magnetic flux density. The purpose of adjusting these characteristics is as follows.

The purpose of reducing the residual magnetic flux density is to improve the fluidity of the two-component developer. That is, a two-component developer using a carrier having magnetite particle powder has a problem of poor fluidity due to magnetic aggregation in the developer. We thought that these problems could be improved by weakening the residual magnetic flux density, in other words, the magnetic cohesion. Further, it is considered that this also leads to an improvement in unnecessary toner release from the drum after the electrostatic transfer is completed in electrophotography.

A further important point in the present invention is that the phosphorus component is contained before the magnetite crystal is formed. Magnetite particles with low magnetic flux density cannot be obtained. The magnetite particles according to the present invention have a residual magnetic flux density of 10 to 5 compared to the case where no phosphorus is added, the residual magnetic flux density of which exceeds 9 Am ² / kg.
Although it is not yet clear why it can be obtained as low as about 0%, the present inventors suppress the aggregation of the growing particles during the formation of the magnetite particles, and have some effect on the crystal growth of the magnetite particles. We think that it is exerting.

Next, various conditions for implementing the present invention will be described.

In the present invention, the aqueous ferrous salt solution includes:
Ferrous sulfate, ferrous chloride, ferrous nitrate and the like, and, as the alkali hydroxide, sodium hydroxide, potassium hydroxide, alkali metals such as calcium hydroxide, hydroxides of alkaline earth metals and Ammonium hydroxide, ammonia gas, or the like can be used.

In the present invention, the amount of the alkali hydroxide relative to the ferrous salt is 0.1 to the Fe ²⁺ in the aqueous ferrous salt solution.
01 to 1.5 equivalents. If the amount is less than 0.01 equivalent, the desired magnetite particle powder of the present invention cannot be obtained. When the amount exceeds 1.5 equivalents, the desired magnetite can be obtained but is not economical.

The reaction temperature for oxidizing ferrous hydroxide in the present invention is 60 to 100 ° C. If the temperature is lower than 60 ° C., the saturation magnetic flux density becomes small. When the temperature exceeds 100 ° C., the magnetite aimed at by the present invention can be obtained, but it is not industrial.

As the oxidizing method, there is a method of passing an oxygen-containing gas such as air or an oxygen gas into a liquid, or a method of adding an oxidizing agent such as hydrogen peroxide. The method of passing an oxygen-containing gas may be used. .

Examples of the water-soluble phosphorus compound used in the present invention include phosphates such as sodium hexametaphosphate and ammonium monophosphate, and phosphoric acids such as orthophosphoric acid and phosphorous acid. The amount of addition of Fe
To 0.03 to 5.0% by weight in terms of P.

If the amount is less than 0.03% by weight, the magnetite particles having a low residual magnetic flux density, which is the object of the present invention, cannot be obtained. On the other hand, if it exceeds 5.0% by weight, the filterability becomes very poor and it is not industrial.

The water-soluble phosphorus compound may be added in alkali hydroxide, in ferrous salt, or in ferrous hydroxide obtained by neutralizing the same. It must be added before crystallization starts.

The form of the magnetite particles may be any of cubic, polyhedral, spherical, needle-like, plate-like and the like, but the magnetite particles may be dispersed uniformly in the composite particles. And spherical ones are preferably used. The average particle size may be a particle smaller than the average particle size of the composite particles, and is preferably 0.02 to 5.0 μm, particularly preferably 0.02 to 2.0 μm.

When the magnetic fine particles and the non-magnetic inorganic compound particles are used in combination, the mixing ratio of the magnetic fine particles is at least 30%.
It is preferable that the inorganic compound particles are contained in a weight percentage of inorganic compound particles.

The whole or a part of the inorganic compound particle powder is treated with a lipophilic treatment agent.

As the lipophilic treatment agent, one or more functional groups selected from epoxy groups, amino groups, mercapto groups, organic acid groups, ester groups, ketone groups, halogenated alkyl groups and aldehyde groups are used. Organic compounds having a group and mixtures thereof can be preferably used, and any of them can achieve the object of the present invention. Of these, coupling agents containing a functional group are preferred, and silane coupling agents are particularly preferred because they can be treated while hydrolyzed in an aqueous medium. Further, as a preferable functional group, an epoxy group, an amino group and a mercapto group are preferable because the inorganic compound powder is easily dispersed uniformly in the carrier. It is preferable in that the charging ability is stabilized.

As the organic compound having an epoxy group,
Epichlorohydrin, glycidol, styrene-glycidyl (meth) acrylate copolymer and the like.

Examples of the silane coupling agent having an epoxy group include γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) trimethoxysilane and the like. is there.

Examples of the organic compound having an amino group include ethylenediamine, diethylenetriamine, and styrene-
And dimethylaminoethyl (meth) acrylate copolymer.

As the silane coupling agent having an amino group, γ-aminopropyltrimethoxysilane, N
-Β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane and the like.

Examples of the titanium-based coupling agent having an amino group include isopropyl tri (N-aminoethyl) titanate.

Examples of the organic compound having a mercapto group include mercaptoethanol and mercaptopropionic acid.

Examples of the silane coupling agent having a mercapto group include γ-mercaptopropyltrimethoxysilane.

Examples of the organic compound having an organic acid group include oleic acid, stearic acid, styrene-acrylic acid and the like.

Examples of the organic compound having an ester group include:
Examples include ethyl stearate and styrene-methyl methacrylate.

Examples of the organic compound having a ketone group include cyclohexanone, acetophenone, and methyl ethyl ketone resin.

Examples of the organic compound having a halogenated alkyl group include chlorohexadecane and chlorodecane.

Examples of the organic compound having an aldehyde group include propionaldehyde and benzaldehyde.

In the present invention, the amount of the lipophilic treatment agent is preferably from 0.1 to 5.0% by weight based on the weight of the inorganic compound particles.

When the amount is less than 0.1% by weight, it is difficult to uniformly disperse the inorganic compound particles in the composite particles due to insufficient lipophilic treatment, and the composite having a high content of the inorganic compound particles is difficult. Body particles cannot be obtained.

If the content exceeds 5.0% by weight, the resin coating can be adhered to the surface of the composite particles, but the formed composite particles aggregate, and the particle size of the composite particles is controlled. It becomes difficult.

The binder resin constituting the composite particles in the present invention is preferably a thermosetting resin.

Examples of thermosetting resins include phenolic resins, epoxy resins, polyamide resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, xylene resins, acetoguanamine resins, furan resins, silicone resins, and polyimide resins. , Urethane resin, etc.
These resins may be used alone or in combination of two or more, but it is preferable that the resin contains at least a phenol resin.

In the present invention, the ratio of the binder resin and the inorganic compound particles constituting the composite particles is 1 to 20% by weight of the binder resin and 80 to 99% of the inorganic compound particles.
% By weight.

The average particle size of the composite particles is particularly preferably 10 to 50 μm for higher image quality and higher quality.
Is more preferable, and the average particle size is more preferably 15 to 45.
μm is even more preferable when original continuous printing with a high image ratio such as a photographic document and a large amount of toner consumption is performed, because the mixed toner transportability of the replenishment toner is excellent.

The carrier according to the present invention may be coated with a coupling agent or a resin, if necessary.

The resin to be coated may be any known resin, for example, epoxy resin, silicone resin,
Polyester resin, fluorine resin, styrene resin, acrylic resin, phenol resin and the like can be used. A polymer obtained by polymerizing from a monomer may be used. A silicone resin is preferable in consideration of durability and stain resistance.

More preferably, the binder resin of the core particles is contained in a phenolic resin, the surface treating agent of the magnetic fine particles is contained in an epoxy group-containing silane coupling agent, a silicone coat resin, or contains an amino group as a pretreatment agent for the core agent. By making the silane coupling agent to be, the silane coupling agent containing an amino group is hydrolyzed by moisture appropriately adsorbed in the binder resin, while forming a hydrogen bond with the hydroxyl group of the phenol resin, At the same time as self-condensing or condensing with the remaining silanol groups in the silicone resin to form a strong coating, the amino groups react with the epoxy group of the surface treatment agent of the magnetic fine particles, improving the adhesion of the silicone resin, The loss of the coating resin and the like are suppressed.

The carrier of the present invention has a true specific gravity of 2.5 to 4.5 (preferably 3.0 to 4.3). When the true specific gravity is within this range, the carrier and the toner are mixed and stirred. This is preferable because the load on the toner is small, the contamination of the carrier surface by the toner is suppressed, and the adhesion of the carrier to the non-image portion on the electrostatic image carrier is preferred.

The carrier of the present invention has a size of 1000 × (10 ³⁾
/ 4π) · A / m (1000 Oersteds) with a magnetization intensity (σ ₁₀₀₀ ) of 20 to 80 Am ² /
kg (emu / g) (more preferably, 25 to 70 A
m ² / kg) and the residual magnetization (σ _r ) is 9 Am ² / kg
Or less (emu / g) (more preferably, 0.1 to 6.
5 Am ² / kg), and when the magnetic properties of the carrier are within this range, the carrier is not affected by the magnetic field of the magnetic field generating means (for example, a fixed magnet) contained in the developer carrier (developing sleeve). This is preferable because carrier adhesion to the electrostatic image carrier is prevented, the compressive force of the two-component developer on the toner in the magnetic brush is reduced, and carrier contamination by external additives and toner particles is suppressed. When the residual magnetization (σ _r ) of the carrier exceeds 9 Am ² / kg, not only does the mixing property with the replenishment toner decrease, but also the two-component developer on the developer carrier and the two-component developer in the developing device. The exchange with the agent is not performed smoothly, and especially when the apparatus is downsized, the charge-up of the toner and the variation in the charge amount of the toner are likely to occur.

The carrier of the present invention has a specific resistance of 5 × 10
A ¹¹ to 5 × 10 ¹⁵ Ω · cm, the specific resistance of the carrier is in this range, the carrier is less likely to adhere the carrier to the electrostatic image bearing member, the charge-up of toner may also be satisfactorily suppressed.

A non-magnetic inorganic compound may be added to the carrier core in addition to the magnetite of the present invention so that the specific resistance value and the residual magnetization of the carrier fall within the predetermined ranges. The fact that the magnetite and the nonmagnetic inorganic compound fine particles are contained in a total amount of 70 to 99% by weight (based on the carrier) (more preferably, 80 to 99% by weight) is required to adjust the true specific gravity of the carrier and the ratio of the carrier. Adjustment of the resistance value,
It is preferable in relation to the mechanical strength of the carrier core.

Further, the non-magnetic inorganic compound fine particles have a larger specific resistance than magnetite, and the number average particle diameter of the non-magnetic inorganic compound fine particles larger than the number average particle diameter of magnetite decreases the specific resistance of the carrier. It is preferable to increase the specific gravity of the carrier and decrease the true specific gravity of the carrier.

The shape of the carrier is appropriately selected so as to be suitable for a predetermined system. However, the sphericity of the carrier is between 100 and 130 (more preferably 1
00 to 120) are preferred. The carrier has a sphericity of 13
If it exceeds 0, the fluidity of the developer will be poor, and the ability to impart frictional charge to the toner will be reduced, and the shape of the magnetic brush will be uneven at the developing pole, making it difficult to obtain high-quality images. .

The sphericity of the carrier was measured by using a field emission scanning electron microscope S-
This is performed by extracting 300 or more carriers at random using 800, and using a Luzex3 image processing / analysis device manufactured by Nireco to determine the sphericity derived by the following equation.

[0077]

(Equation 1) [Where MXLNG indicates the maximum diameter of the carrier, and ARE
A indicates the projected area of the carrier. Here, SF-1 closer to 100 means closer to a sphere.

Next, a method for manufacturing a carrier according to the present invention will be described.

The composite particles are obtained by dispersing an inorganic compound particle powder dispersed in a solvent into a monomer constituting a binder resin, and adding an initiator or a catalyst to polymerize.
It can be produced by a polymerization method or a so-called kneading and pulverizing method in which a binder resin containing inorganic compound particle powder is pulverized. A polymerization method is preferred for easily controlling the particle size of the magnetic carrier and obtaining a sharp particle size distribution.

In the production of composite particles using a phenol resin as a binder resin, for example, phenols and aldehydes and an inorganic compound particle powder which has been subjected to lipophilic treatment are dispersed in an aqueous medium, and a basic catalyst is added. Reaction. A method of forming a so-called modified phenol resin by mixing and reacting a natural resin such as rosin or a drying oil such as tung oil or linseed oil with phenols is also included.

When the binder resin is a phenol resin in particular, it is preferable because it retains a suitable amount of adsorbed water, promotes the hydrolysis of the coupling agent, and forms a strong coating.

The production of composite particles using an epoxy resin as a binder resin is performed, for example, by dispersing bisphenols, epihalohydrin and lipophilic inorganic compound particles in an aqueous medium, and reacting in an alkaline aqueous medium. There is a method to make it.

The production of composite particles using a melamine resin as a binder resin is carried out, for example, by dispersing melamines and aldehydes and an inorganic compound particle powder subjected to lipophilic treatment in an aqueous medium. Reaction in the presence of

Other methods for producing composite particles using a thermosetting resin include, for example, kneading inorganic compound particle powder which has been subjected to a lipophilic treatment with various resins, and pulverizing the mixture.
Further, a method of performing a spheroidizing process and the like can be mentioned.

The composite particles composed of the inorganic compound particles subjected to the lipophilic treatment and the binder resin may be subjected to a heat treatment if necessary in order to further harden the resin. It is particularly preferable to carry out the reaction under reduced pressure or in an inert atmosphere in order to prevent oxidation of the inorganic compound fine particles and the like.

The coating treatment of the composite particles with the coupling agent may be carried out by immersing the composite particles in a solution of the coupling agent in water or a solvent by a conventional method, followed by filtration and drying. A method of spraying and drying an aqueous solution or a solvent solution of the coupling agent with stirring is used. In particular, in order to prevent coalescence of the composite particles and form a uniform coating layer, a method of performing treatment with stirring is preferable.

The resin may be coated by a known method, for example, a method of dry-mixing the composite particles and the resin using a Henschel mixer or a high-speed mixer, or a method of coating the composite particles in a solvent containing the resin. How to impregnate,
Any method such as spraying a resin onto the composite particles using a spray dryer may be used.

Next, the toner used in the developer of the present invention will be described.

The toner according to the present invention has a weight average particle size of 3.
0 to 9.0 μm, preferably 4.5 to 8.5 μm.

When the weight average particle diameter (D4) of the toner exceeds 9 μm, the toner particles for developing the electrostatic image become large, so that the development faithful to the electrostatic image can be performed even if the magnetic force of the magnetic coat carrier is reduced. It is difficult to perform the transfer, and the toner is easily scattered when the electrostatic transfer is performed. On the other hand, a toner having a weight average particle diameter of less than 3 μm has poor powder handling properties.

The particle size distribution of the toner can be measured, for example, by a method using a Coulter counter.

As the binder resin used for the toner, the following binder resins can be used.

For example, homopolymers of styrene and its substituted substances such as polystyrene, poly-p-chlorostyrene and polyvinyltoluene; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-
Vinyl naphthalene copolymer, styrene-acrylic ester copolymer, styrene-methacrylic ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-
Styrene such as vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer -Based copolymer; polyvinyl chloride; phenolic resin; natural modified phenolic resin; natural resin modified maleic acid resin; acrylic resin; methacrylic resin; polyvinyl acetate; silicone resin; polyester resin; A xylene resin; a polyvinyl butyral; a terpene resin; a cumarone indene resin; Preferred binder resins include styrene copolymers and polyester resins.

Further, a crosslinked styrene resin is also a preferable binder resin.

The styrene-based polymer or styrene-based copolymer may be crosslinked, or may be a mixed resin of a crosslinked resin and a non-crosslinked resin.

As a crosslinking agent for the binder resin, a compound having two or more polymerizable double bonds may be mainly used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; ethylene glycol diacrylate, ethylene glycol dimethacrylate,
Carboxylic acid esters having two double bonds such as 1,3-butanediol dimethacrylate; divinyl compounds such as divinylaniline, divinylether, divinylsulfide and divinylsulfone; and compounds having three or more vinyl groups. Can be These are used alone or as a mixture.

The amount of the crosslinking agent to be added may be as follows.
0.001 to 10 parts by weight based on 00 parts by weight is preferred.

The toner may contain a charge control agent.

The following substances control the toner to be negatively charged.

For example, organic metal compounds and chelate compounds are effective, and monoazo metal compounds, acetylacetone metal compounds, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid-based metal compounds are preferably used. Further, aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, their anhydrides, their esters, their phenol derivatives such as bisphenol; urea derivatives; metal-containing salicylic acid-based compounds; Metal naphthoic acid compound; boron compound;
Quaternary ammonium salts; calixarenes; silicon compounds; styrene-acrylic acid copolymers; styrene-methacrylic acid copolymers; styrene-acrylic-sulfonic acid copolymers; and nonmetal carboxylic acid compounds.

These charge control agents are used in an amount of 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 0.2 to 4 parts by weight, based on 100 parts by weight of the resin component of the toner. Good to do.

As the colorant of the toner used in the present invention, carbon black, a magnetic substance, and a black color toned using a yellow / magenta / cyan colorant shown below are used.

Examples of the yellow colorant 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 or 180 are preferably used. Further, C.I. I. Dyes such as Solvent Yellow 93, 162 and 163 may be used in combination.

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
44, 146, 166, 169, 177, 184, 18
5, 202, 206, 220, 221 or 254 are preferably used.

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 can be particularly preferably used.

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

Further, the wax is used as the binder resin 10 of the toner.
1 to 40 parts by weight per 0 parts by weight, preferably 2 to 40 parts by weight
You may mix 30 weight part.

In the production of a pulverized toner in which a mixture having a binder resin, a colorant and a wax is melt-kneaded, cooled, pulverized and then classified to obtain toner particles, the amount of the wax added is 100 parts by weight of the binder resin. It is preferable to use 1 to 10 parts by weight, more preferably 2 to 7 parts by weight.

In a polymerized toner production method in which toner particles are directly obtained by polymerizing a mixture containing a polymerizable monomer, a colorant and a wax, the amount of the wax added depends on the amount of the polymerizable monomer or polymerizable monomer. 2 to 40 parts by weight, more preferably 5 to 30 parts by weight, even more preferably 10 to 2 parts by weight per 100 parts by weight of the resin synthesized by polymerization of the monomer.
It is preferred to use 0 parts by weight.

Since the wax used in the polymerization toner production method is lower in polarity than the binder resin as compared with the pulverized toner production method, a large amount of wax is easily encapsulated inside the toner particles in the polymerization method in an aqueous medium. In comparison, a large amount of wax can be used, which is particularly effective for the effect of preventing offset during fixing.

If the compounding amount of the wax is less than the lower limit, the offset prevention effect tends to decrease, and if it exceeds the upper limit, the anti-blocking effect is reduced and the anti-offset effect is liable to be adversely affected. In particular, in the case of a polymerization toner production method, a toner having a wide particle size distribution tends to be produced.

Next, a method for producing the toner used in the present invention will be described. The toner used in the present invention can be manufactured by using a known pulverized toner manufacturing method and a polymerized toner manufacturing method.

In the present invention, a method for producing a pulverized toner includes a binder resin, a wax, a pigment as a colorant, a dye or a magnetic substance, a charge control agent, and other additives as necessary. The resulting mixture is melt-kneaded using a heat kneader such as a heating roll, kneader, extruder and the like, and the metal components, pigments, dyes, and magnetic materials are mixed while the resin components are mutually mixed. The kneaded product is cooled and solidified, and then pulverized and classified to obtain a toner.

Further, if necessary, the toner and the desired additives are sufficiently mixed by a mixer such as a Henschel mixer.
The toner used in the present invention can be obtained.

A method for producing a polymerized toner is described in JP-B-56-13.
No. 945, etc., a method of atomizing a molten mixture into air using a disk or a multi-fluid nozzle to obtain a spherical toner, Japanese Patent Publication No. Sho 36-10231, and Japanese Patent Application Laid-Open No. Sho 59-53.
No. 856, JP-A-59-61842, a method of directly producing a toner using a suspension polymerization method, an aqueous organic solvent which is soluble in a monomer and insoluble in a polymer obtained. An emulsion polymerization method typified by a dispersion polymerization method in which a toner is directly produced using a water-soluble polar polymerization initiator or a soap-free polymerization method in which a toner is produced by directly polymerizing in the presence of a water-soluble polar polymerization initiator, or a method in which primary polar emulsion polymerization particles are previously prepared. It is possible to produce a toner using a hetero-aggregation method in which polar particles having opposite charges are added and associated.

Of these, the method of directly polymerizing a monomer composition containing at least a polymerizable monomer, a colorant and a wax to form toner particles is preferred.

A so-called seed polymerization method in which a monomer is further adsorbed on the polymer particles once obtained and then polymerized using a polymerization initiator can also be suitably used in the present invention.

Next, the external additives externally added to the toner particles will be described.

The toner used in the present invention comprises inorganic fine particles such as silica, alumina, and titanium oxide; and fine organic fine particles such as polytetrafluoroethylene, polyvinylidene fluoride, polymethyl methacrylate, polystyrene, and silicone. It is preferable that it is done. By externally adding the above-described fine powder to the toner, the fine powder exists between the toner and the carrier or between the toner particles, whereby the fluidity of the developer is improved, and the life of the developer is also increased. improves. The average particle size of the fine powder described above is preferably 0.2 μm or less. When the average particle size exceeds 0.2 μm, the effect of improving the fluidity decreases,
In some cases, image quality is degraded due to a defect during development or transfer. The measurement of the average particle size of these fine powders will be described later.

The surface area of these fine powders is BET
Specific surface area by nitrogen adsorption 30 m ² / g or more by law, is excellent particularly in the range of 5~400m ² / g. The addition amount of the fine powder is preferably 0.1 to 20 parts by weight based on 100 parts by weight of the toner.

Since the toner is a negatively chargeable toner, it is preferable to use at least one kind of silica subjected to hydrophobic treatment from the viewpoint of chargeability. That is, since silica has a higher negative chargeability than a fluidizing agent such as alumina or titanium oxide, the adhesion to the toner matrix is high, and the amount of liberated external additives is reduced. Therefore, filming on the electrostatic image carrier and contamination of the charging member can be suppressed. However, when the negative chargeability is increased, the external additive that has been partially released tends to migrate to the carrier. Even in such a case, the coupling agent-coated carrier of the present invention can easily align the siloxane moiety on the surface and can suppress the adhesion of the fluidizing agent due to its low surface energy.

The silica is preferably subjected to a hydrophobic treatment in order to maintain the chargeability under high humidity. An example of the hydrophobic treatment is shown below.

One of the hydrophobizing agents is a silane coupling agent. The amount of the silane coupling agent is 1 to 40 parts by weight, preferably 2 to 35 parts by weight, based on 100 parts by weight of the inorganic fine powder. Is good. When the amount is 1 to 40 parts by weight, moisture resistance is improved and aggregates are hardly generated.

As another hydrophobizing agent, silicone oil can be mentioned.

Additives for imparting various toner properties may have a particle size of not more than 1/5 of the volume average particle size of the toner particles from the viewpoint of durability when added to the toner or when added to the toner. preferable. The particle size of the additive means an average particle size obtained by observing the surface of the toner particles with an electron microscope. As additives for the purpose of imparting these properties, for example, the following are used.

Examples of the fluidity-imparting agent include metal oxides such as silicon oxide, aluminum oxide and titanium oxide;
Carbon black; and carbon fluoride.
Each of these is preferably subjected to a hydrophobic treatment.

Examples of the abrasive include metal oxides such as strontium titanate, cerium oxide, aluminum oxide, magnesium oxide and chromium oxide; nitrides such as silicon nitride; carbides such as silicon carbide; and calcium sulfate and sulfuric acid. Metal salts such as barium and calcium carbonate are mentioned.

Examples of the lubricant include fluorine resin powders such as vinylidene fluoride and polytetrafluoroethylene; and fatty acid metal salts such as zinc stearate and calcium stearate.

As the charge control particles, for example, tin oxide,
Metal oxides such as titanium oxide, zinc oxide, silicon oxide and aluminum oxide; and carbon black.

These additives are preferably used in an amount of 0.1 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the toner particles. These additives may be used alone or in combination of two or more.

In the present invention, when a two-component developer is prepared by mixing a toner and a carrier, the mixing ratio is 2 to 15% by weight as the toner concentration in the developer.
Good results are obtained when the content is preferably 4% to 13% by weight. If the toner concentration is less than 2% by weight, the image density tends to be low, and if it exceeds 15% by weight, fogging and scattering in the machine are liable to occur, and the useful life of the developer tends to decrease.

The ratio a / b of the weight average particle diameter a of the toner to the number average particle diameter b of the carrier is preferably 0.1 to 0.3. If the ratio is less than 0.1, it becomes difficult to appropriately charge the toner, and fog or toner scattering in a high humidity environment is likely to occur. On the other hand, if it exceeds 0.3, the charge amount of the toner particularly under low humidity becomes too high, which tends to cause a decrease in image density and fog.

As a developing method using the carrier of the present invention, for example, development can be performed using a developing means as shown in FIG. Specifically, it is preferable to perform development in a state where the magnetic brush is in contact with the latent image carrier, for example, the photosensitive drum 1 while applying an alternating electric field. The distance (S-D distance) B between the developer carrier (developing sleeve) 11 and the photosensitive drum 1 is preferably 100 to 1000 [mu] m in order to prevent carrier adhesion and improve dot reproducibility.
If it is smaller than 100 μm, the supply of the developer tends to be insufficient and the image density is lowered. If it is larger than 1000 μm, the magnetic field lines from the magnetic pole S ₁ are widened and the density of the magnetic brush is reduced, resulting in poor dot reproducibility or poor carrier performance. The binding force is weakened and carrier adhesion is likely to occur.

The voltage between the peaks of the alternating electric field is 300 to 30.
00V is preferable, the frequency is 500 to 10000 Hz,
Preferably, it is 1000-7000 Hz, and each can be appropriately selected and used depending on the process. In this case, the waveform may be triangular, rectangular, sine, or D
Various waveforms with different duty ratios, intermittent alternating superposed electric fields, and the like can be selected and used. If the applied voltage is lower than 300 V, it may be difficult to obtain a sufficient image density, and it may not be possible to satisfactorily collect fog toner in the non-image area. If the voltage exceeds 5000 V, the latent image may be disturbed via the magnetic brush, which may cause deterioration in image quality.

By using a two-component developer having a well-charged toner, the fog removal voltage (Vback)
And the primary charge of the photoconductor can be reduced, so that the life of the photoconductor can be extended. Vbac
k is preferably 200 V or less, more preferably 150 V or less, depending on the developing system.

The contrast potential is preferably from 100 V to 400 V so that a sufficient image density can be obtained.

When the frequency is lower than 500 Hz, although it depends on the process speed, when the toner in contact with the electrostatic image carrier is returned to the developing sleeve, sufficient vibration is not given and fog is liable to occur. When the frequency exceeds 10,000 Hz, the toner cannot follow the electric field, and the image quality is liable to be deteriorated.

In the image forming method of the present invention, three or more developing units for magenta, cyan and yellow are used in outputting a full-color image especially when halftone is emphasized. By using the developing method, particularly in combination with a developing system that forms a digital latent image, it is possible to develop the dot latent image faithfully without being affected by the magnetic brush and disturbing the latent image. Also in the transfer step, a high transfer rate can be achieved by using a fine-particle-cut toner having a sharp particle size distribution, so that high image quality can be achieved in both the halftone portion and the solid portion.

Further, by using the two-component developer of the present invention together with the initial improvement of image quality, the share of the developer in the developing device is small, and the present invention does not cause a deterioration in image quality even when copying a large number of sheets. The effect of can be fully exhibited.

In order to obtain a tighter image, it is preferable to have a developing device for magenta, cyan, yellow, and black, and to exhibit a tighter image by performing black development last. Can be.

An image forming method according to the present invention will be described with reference to the accompanying drawings.

In FIG. 1, a magnetic brush made of magnetic particles 23 is formed on the surface of the transfer sleeve 22 by the magnetic force of the magnet roller 21, and this magnetic brush contacts the surface of the electrostatic image carrier (photosensitive drum) 1. Then, the photosensitive drum 1 is charged. A charging bias is applied to the transport sleeve 22 by a bias applying unit (not shown). By irradiating the charged photosensitive drum 1 with laser light 24 by an exposure device (not shown), a digital electrostatic charge image is formed. The electrostatic charge image formed on the photosensitive drum 1 includes a magnet roller 12 and a developer 19 carried on a developing sleeve 11 to which a developing bias is applied by a bias applying device (not shown).
It is developed by the toner 19a inside.

The developing device 4 includes a partition 17 and a developer chamber R.
_1, is divided into the stirring chamber R _2, respectively developer conveying screw 13, 14 is installed. Above the stirring chamber R _2, a toner storage chamber R ₃ containing a replenishing toner 18 is installed, supply opening 20 is provided in a lower portion of the storage chamber R _3.

The developer transport screw 13 rotates to transport the developer in the developer chamber R1 in _one direction along the longitudinal direction of the developing sleeve 11 while stirring. The partition 17 is provided with openings (not shown) on the near side and the back side in the drawing, and the developer conveyed to _one of the developer chambers R1 by the screw 13 passes through the opening of the partition 17 on one side. The developer is sent to the stirring chamber R ₂ and transferred to the developer transport screw 14. In the direction of rotation the screw 13 opposite the screw 14, the developer in the stirring chamber R _2, the developer chamber R ₁
Stirring the toner supplied from the passed developer and toner storage chamber R ₃ from, with mixing, the screw 13 and conveyed in the stirring chamber R ₂ in the opposite direction, through the other opening of the partition wall 17 sent into the developer chamber R _1.

[0145] To develop the electrostatic latent image formed on the photosensitive drum 1, the developer 19 in the developer chamber R ₁ is drawn up by the magnetic force of the magnet roller 12, the developing sleeve 1
1 is carried on the surface. The developer carried on the developing sleeve 11 is conveyed to the regulating blade 15 with the rotation of the developing sleeve 11, where it is regulated to a thin developer layer having an appropriate layer thickness. To the development area opposed to it. The portion corresponding to the developing area of the magnet roller 12, the magnetic poles are (developing pole) N ₁ is positioned, the developing pole N ₁ forms a developing magnetic field in the developing area,
This developer magnetic field causes the developer to spike, and a magnetic brush of the developer is generated in the development area. Then, the magnetic brush contacts the photosensitive drum 1, and the toner adhered to the magnetic brush and the toner adhered to the surface of the developing sleeve 11 are transferred to the electrostatic image area on the photosensitive drum 1 by the reversal developing method. Then, the electrostatic image is developed to form a toner image.

The developer that has passed through the developing area is returned into the developing device 4 with the rotation of the developing sleeve 11, and the magnetic pole S
Due to the repelling magnetic field between S ₁ and S ₂ , it is peeled off from the developing sleeve 11 and falls into the developer chamber R ₁ and the stirring chamber R ₂ to be collected.

By the above development, the developer 1 in the developing device 4
T / C ratio of 9 (toner and mixing ratio of the carrier, i.e., toner concentration in the developer) When decreases is, the agitation chamber R in an amount that was seen from the toner storage chamber R ₃ to the amount consumed toner 18 in the developing ₂ and the T / C of the developer 19 is maintained at a predetermined amount. To detect the T / C ratio of the developer 19 in the container 4,
A toner concentration detection sensor that measures a change in the magnetic permeability of the developer using the inductance of the coil is used. The toner concentration detection sensor has a coil (not shown) therein.

The regulating blade 15 disposed below the developing sleeve 11 and regulating the layer thickness of the developer 19 on the developing sleeve 11 is a non-magnetic blade 15 made of a non-magnetic material such as aluminum or SUS316. The distance between the end and the surface of the developing sleeve 11 is 300 to 1000 μm.
m, preferably 400 to 900 μm. If the distance is less than 300 μm, the magnetic carrier is clogged during this time, and the developer layer is likely to be uneven, and it is difficult to apply the developer necessary for good development, and a developed image having a low density and many unevenness is formed. Easy to be. This distance is preferably 400 μm or more in order to prevent non-uniform application (so-called blade jam) due to unnecessary particles mixed in the developer. If it is larger than 1000 μm, the amount of the developer applied on the developing sleeve 11 increases, and it is difficult to regulate a predetermined thickness of the developer layer. The regulation of development by the blade 15 is weakened, so that toner tribo is reduced and fogging is likely to occur.

Even when the developing sleeve 11 is driven to rotate in the direction indicated by the arrow, the magnetic carrier particle layer moves away from the sleeve surface due to the balance between the restraining force based on magnetic force and gravity and the conveying force in the moving direction of the developing sleeve 11. Movement slows down. Some fall under the influence of gravity.

Therefore, by appropriately selecting the arrangement positions of the magnetic poles N and N and the fluidity and magnetic characteristics of the magnetic carrier particles, the magnetic carrier particle layer becomes closer to the sleeve so that the magnetic pole N ₁ becomes closer to the sleeve.
To form a moving layer. Due to the movement of the magnetic carrier particles, the developer is conveyed to the developing area with the rotation of the developing sleeve 11 and is used for development.

The developed toner image is transferred onto a transfer material (recording material) 25 which is conveyed by a bias applying means 2.
The toner image transferred by the transfer blade 27 as a transfer unit to which a transfer bias is applied by 6 and transferred onto the transfer material is fixed to the transfer material by a fixing device (not shown). In the transfer step, the transfer residual toner remaining on the photosensitive drum 1 without being transferred to the transfer material is adjusted in charge in the charging step, and is collected during development.

FIG. 3 is a schematic diagram in which the image forming method of the present invention is applied to a full-color image forming apparatus employing a cleanerless system.

The main body of the full-color image forming apparatus includes a first image forming unit Pa, a second image forming unit Pb,
An image forming unit Pc and a fourth image forming unit Pd are provided side by side, and images of different colors are formed on a transfer material through a process of forming, developing, and transferring a latent image.

The configuration of each image forming unit provided in the image forming apparatus will be described with reference to the first image forming unit Pa as an example.

The first image forming unit Pa includes an electrophotographic photosensitive drum 6 having a diameter of 30 mm as an electrostatic image carrier.
1a, the photosensitive drum 61a is rotated in the direction of arrow a. Reference numeral 62a denotes a primary charger as a charging unit, and a magnetic brush formed on the surface of a sleeve having a diameter of 16 mm is arranged so as to contact the surface of the photosensitive drum 61a. Reference numeral 67a denotes a laser beam for forming an electrostatic charge image on the photosensitive drum 61a, the surface of which is uniformly charged by the primary charger 62a, and is irradiated by an exposure device (not shown). 63a is the photosensitive drum 6
The developing device is a developing device as a developing unit for forming a color toner image by developing the electrostatic charge image carried on 1a, and holds a color toner. Reference numeral 64a denotes a transfer blade as transfer means for transferring the color toner image formed on the surface of the photosensitive drum 61a to the surface of a transfer material (recording material) conveyed by a belt-shaped transfer material carrier 68. The transfer blade 64a can apply a transfer bias by contacting the back surface of the transfer material carrier 68.

In the first image forming unit Pa, after the photosensitive drum 61a is uniformly and primarily charged by the primary charger 62a, an electrostatic image is formed on the photosensitive member by the exposure device 67a, and the electrostatic image is formed by the developing device 63a. Is developed using a color toner, and the developed toner image is transferred to a back surface side of a belt-shaped transfer material carrier 68 which carries and conveys the transfer material at a first transfer portion (a contact position between the photoconductor and the transfer material). A transfer bias is applied from a transfer blade 64a that comes into contact with the transfer member to transfer the image onto the surface of the transfer material.

When the toner is consumed by the development and the T / C ratio decreases, the decrease is detected by a toner concentration detection sensor 85 which measures the change in the magnetic permeability of the developer by using the inductance of the coil, and is consumed. The supply toner 65 is supplied according to the toner amount. The toner density detection sensor 85 has a coil (not shown) therein.

This image forming apparatus has the same configuration as the first image forming unit Pa, and has the second image forming unit Pb, the third image forming unit Pc, and the third image forming unit Pc having different colors of the color toner held in the developing device. Four image forming units of the fourth image forming unit Pd are provided side by side. For example, yellow toner is used for the first image forming unit Pa, magenta toner is used for the second image forming unit Pb, cyan toner is used for the third image forming unit Pc, and black toner is used for the fourth image forming unit Pd. The transfer of each color toner onto the transfer material is sequentially performed in the transfer section of each image forming unit. In this step, while the registration is being performed, each color toner is superimposed on the same transfer material by one transfer of the transfer material, and when the transfer is completed, the transfer material is separated from the transfer material carrier 68 by the separation charger 69. The sheet is sent to the fixing device 70 by a conveying means such as a conveying belt, and the final full-color image is obtained by a single fixing.

The fixing device 70 has a pair of a fixing roller 71 having a diameter of 40 mm and a pressing roller 72 having a diameter of 30 mm. The fixing roller 71 has heating means 75 and 76 inside.

The unfixed color toner image transferred onto the transfer material passes through a pressure contact portion between the fixing roller 71 and the pressure roller 72 of the fixing device 70, and is applied to the transfer material by the action of heat and pressure. Is established.

In FIG. 3, the transfer material carrier 68 is an endless belt-like member, which is moved in the direction of arrow e by a driving roller 80. 7
9 is a transfer belt cleaning device, 81 is a belt driven roller, and 82 is a belt static eliminator. 8
Reference numeral 3 denotes a pair of registration rollers for conveying the transfer material in the transfer material holder to the transfer material carrier 68.

The transfer means is a contact transfer in which a transfer bias can be directly applied by contacting the back surface of a transfer material carrier such as a roller-shaped transfer roller instead of the transfer blade contacting the back surface of the transfer material carrier. Means can be used.

Further, a non-contact type in which a transfer bias is applied from a corona charger arranged in a non-contact manner on the back side of a generally used transfer material carrier in place of the above-mentioned contact transfer means to perform transfer. May be used.

However, it is more preferable to use the contact transfer means in that the amount of ozone generated when the transfer bias is applied can be controlled.

In the image forming method of the present invention, a toner image obtained by developing the electrostatic image formed on the latent image bearing member can be transferred to a recording material via an intermediate transfer member.

Hereinafter, specific examples of the measuring method used in the present invention will be described.

(1) Measuring Method of Toner Particle Size 0.1 to 5 ml of a surfactant (alkylbenzene sulfonate) is added to 100 to 150 ml of the electrolyte solution, and 2 to 20 mg of a measurement sample is added thereto. The electrolytic solution in which the sample was suspended was subjected to dispersion treatment for 1 to 3 minutes with an ultrasonic disperser, and 17 μm
Alternatively, a particle size distribution of 0.3 to 40 μm is measured on the basis of the volume by using an aperture appropriately adjusted to the toner size such as 100 μm. The number average particle size and the weight average particle size measured under these conditions were determined by computer processing, and 1 / of the number average particle size was determined from the number-based particle size distribution.
The cumulative ratio below the double diameter cumulative distribution is calculated, and the cumulative value below the 1/2 diameter cumulative distribution is calculated. Similarly, a cumulative ratio equal to or larger than the double diameter cumulative distribution of the weight average particle diameter is calculated from the volume-based particle size distribution, and a cumulative value equal to or larger than the double diameter cumulative distribution is obtained.

(2) Method for Measuring the Particle Size of Magnetic Fine Particles (Non-magnetic Fine Particles) From a transmission electron micrograph (magnification: 30,000), 50 particle diameters on the photograph are measured, and the average is defined as the particle diameter.

(3) Method for Measuring Particle Size of Carrier The volume average particle size was measured by a laser diffraction type particle size distribution meter (manufactured by Horiba, Ltd.).

(4) Method of Measuring Magnetic Properties of Carriers and Magnetic Particles The magnetization value (σ ₁₀₀₀ ) and residual magnetization value (σ _r ) were measured using a vibrating sample magnetometer VSM-3S-15 (manufactured by Toei Kogyo KK). It measured using.

(5) Method of Measuring True Specific Gravity The true specific gravity was measured with a multi-volume density meter (Micromeritics).

(6) Method of measuring volume specific resistance: Measured with a high resistance meter 4329A (manufactured by Yokogawa Hewlett-Packard Company).

More specifically, the specific resistance of the magnetic fine particles or the carrier is measured using a measuring device shown in FIG. The cell E is filled with magnetic fine particles or a carrier, and the sample 12
The electrodes 121 and 122 are disposed so as to be in contact with the magnetic fine particles or the carrier filled as 7, and a voltage is applied between the electrodes, and a current flowing at that time is measured to obtain a specific resistance. In the above-mentioned measuring method, since the magnetic fine particles or the carrier are powder, a change occurs in the filling rate, and the specific resistance may change with the change. The measurement conditions of the specific resistance were as follows: the contact area S between the filled magnetic fine particles or carrier and the electrode was about 2.3 cm ² , and the thickness d was about 2 m.
m, the load of the upper electrode 22 is 180 g, and the applied voltage is 100 V.

(7) Measuring method of triboelectric charge 1.6 g of the toner and 18.4 g of the magnetic carrier are placed in a 50 cc polyethylene container, and left open for one day under each environment. In a high-temperature and high-humidity environment, the sample is sealed after standing and the apparatus is further left for 2 hours so that the sample does not dew. Mix the powder (developer) in a metal container equipped with a 625 mesh conductive screen at the bottom, suction with a suction machine, and mix the powder with the weight difference before and after suction. The amount of triboelectric charge is determined from the potential stored in the connected capacitor. At this time, the suction pressure is 2
It is 50 mmHg. With this method, the triboelectric charge amount is calculated using the following equation.

Q (mC / kg) = (C × V) × (W ₁ −W ₂ ) ⁻¹ (where W ₁ is the weight before suction, W ₂ is the weight after suction, and C Is the capacity of the capacitor, and V is the potential stored in the capacitor.)

Further, the amount of triboelectric charge of the toner of the developer at the time of the endurance was determined by sampling 1 g of the developer on the developing sleeve,
The measurement was performed using the above-mentioned measuring device without mixing and stirring.

(8) P Content in Magnetic Fine Particles The P content in the particle powder was determined using a fluorescent X-ray analyzer “RIX300
Using "0" (manufactured by Rigaku Denki Kogyo), X-ray fluorescence analysis was performed.

[0178]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Production Examples and Examples, but this does not limit the present invention in any way. The number of parts described in the examples indicates parts by weight.

(Production Example 1 of Hydrophobic Iron Oxide) Sodium hexametaphosphate previously prepared in a reactor
3.04 mol / L of NaOH to which 21 g (corresponding to 0.5% by weight in terms of P with respect to Fe) was added.
1.6 L of an aqueous solution of ferrous sulfate containing 1.5 mol / L of Fe ²⁺ was added to 4.4 L of the aqueous solution to produce ferrous hydroxide (the amount of alkali hydroxide used was F
This corresponds to 1.05 equivalents to e ²⁺ . ). At a temperature of 90 ° C., 2 liters of air per minute was passed for 120 minutes while mechanically stirring the ferrous hydroxide to obtain magnetite particles. The generated particles are washed, filtered, dried, pulverized,
Magnetite particles I were obtained. The magnetite particles I were subjected to a surface treatment with 0.5 part of γ-glycidyltrimethoxysilane to obtain a hydrophobic iron oxide I having physical properties shown in Table 1.

(Production Examples 2-8 of Hydrophobic Iron Oxide) Magnetite particles II were prepared in the same manner as in Example 1 except that the kind, amount and timing of addition of the water-soluble P compound and the amount of alkali used were variously changed. -VIII and hydrophobic iron oxide II-
VIII was obtained. Table 1 shows the main production conditions at this time and the physical properties of the formed hydrophobic oxide.

The hydrophobic iron oxides I-VI obtained in Production Examples 1 to 6 of the hydrophobic iron oxides all had low residual magnetic flux densities (9 Am ² / kg or less).

[0182]

[Table 1]

(Production Example 1 of Magnetic Carrier) ・ 50 parts of phenol (hydroxybenzene) ・ 80 parts of 37% by weight aqueous formalin solution ・ 50 parts of water ・ 600 parts of hydrophobic iron oxide I ・ 15 parts of 25% by weight aqueous ammonia

The above materials were placed in a four-necked flask, and the temperature was raised to 85 ° C. in 60 minutes while stirring and mixing, and the mixture was reacted and cured for 120 minutes. After cooling to 30 ° C. and addition of 500 parts of water, the supernatant was removed, the precipitate was washed with water and air-dried. This was then reduced under reduced pressure (5 mmHg) 15
After drying at 0 to 180 ° C. for 24 hours, a magnetic carrier core (A) using a phenol resin as a binder resin was obtained. 0.4% by weight of adsorbed water was present in the magnetic carrier core (A) at 30 ° C./80% for 24 hours.

A 5% by weight solution of γ-aminopropyltrimethoxysilane in toluene was applied to the surface of the obtained magnetic carrier core (A).

The surface of the magnetic carrier core (A) was 0.2
It had been treated with γ-aminopropyltrimethoxysilane by weight. During the application, the toluene was volatilized while applying while continuously applying shear stress to the magnetic carrier core (A). On the surface of the magnetic carrier core (A)

[0187]

Embedded image Was confirmed to be present.

While stirring the magnetic carrier core (A) treated with the silane coupling agent in the above-mentioned processing machine at 70 ° C., the silicone resin KR-221 (manufactured by Shin-Etsu Chemical Co., Ltd.) was added to the silicone resin solid component. 3% γ-
Aminopropyltrimethoxysilane was added, diluted with toluene so as to have a silicone resin solid content of 20%, and then added under reduced pressure to coat the resin.

Thereafter, after stirring for 2 hours, heat treatment was performed at 140 ° C. for 2 hours in an atmosphere of nitrogen gas to loosen agglomeration, and coarse particles of 200 mesh or more were removed. I was obtained.

(Production Examples 2 to 8 of Magnetic Carrier) Production Example 1
In place of the hydrophobic iron oxide I, the hydrophobic iron oxide I
Magnetic carriers II to VIII having physical properties shown in Table 2 were obtained in the same manner except that I to VIII were used.

(Production Example 9 of Magnetic Carrier) In Production Example 1, magnetite particles I were used instead of hydrophobic iron oxide I.
The magnetic carrier IX having the physical properties shown in Table 2 was obtained in the same manner except that.

(Production Example 10 of Magnetic Carrier) In Production Example 1, 540 parts of hydrophobic iron oxide I were prepared, and the average particle diameter was 0.35.
A magnetic carrier X having the physical properties shown in Table 2 was obtained in the same manner except that 60 parts of a hydrophobic hematite having a thickness of μm was used.

(Production Example 11 of Magnetic Carrier) In Production Example 1, 420 parts of hydrophobic iron oxide II was used instead of hydrophobic iron oxide I, and hydrophobic hematite 1 having an average particle size of 0.35 μm was used.
A magnetic carrier XI having physical properties shown in Table 2 was obtained in the same manner except that 80 parts were used.

(Production Example 12 of Magnetic Carrier) A magnetic carrier XII having the physical properties shown in Table 2 was obtained in the same manner as in Production Example 1, except that the silicone resin was not coated.

(Production Example 13 of Magnetic Carrier) A magnetic carrier XIII having physical properties shown in Table 2 was obtained in the same manner as in Production Example 1, except that γ-aminopropyltrimethoxysilane was not used on the surface of the magnetic carrier.

[0196]

[Table 2]

Toner Production Example 1 450 parts of a 0.1 M Na ₃ PO ₄ aqueous solution was charged into 710 parts of ion-exchanged water, heated to 60 ° C., and then subjected to a TK homomixer (manufactured by Tokushu Kika Kogyo). And stirred at 1300 rpm. To this, 68 parts of a 1.0 M CaCl ₂ aqueous solution was gradually added to obtain a pH 6 aqueous medium containing Ca ₃ (PO ₄ ) ₂ . 160 parts of styrene 34 parts of n-butyl acrylate 12 parts of copper phthalocyanine pigment 2 parts of metal compound ditertiary butyl salicylate 10 parts of saturated polyester (acid value 10 mg KOH / g, peak molecular weight 8500) Monoester wax 20 parts (Mw : 500, Mn: 400, Mw / Mn: 1.2
5, melting point: 69 ° C., viscosity: 6.5 mPa · s, Vickers hardness: 1.1, SP value: 8.6)

The above-mentioned material was heated to 60 ° C., and a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) was used.
To dissolve and disperse uniformly. In addition, polymerization initiator 2,
2'-azobis (2,4-dimethylvaleronitrile) 1
0 g was dissolved to prepare a polymerizable monomer composition. The polymerizable monomer composition was charged into the aqueous medium, and the mixture was heated at 60 ° C. and N ₂
Under an atmosphere, the mixture was stirred at 10,000 rpm for 10 minutes with a CLEAR MIXER (manufactured by M Technique Co., Ltd.) to granulate the polymerizable monomer composition. Thereafter, the temperature was raised at 80 ° C. while stirring the aqueous medium with a paddle stirring blade, and a polymerization reaction was carried out for 10 hours while maintaining the pH at 6.

After the completion of the polymerization reaction, the mixture was cooled, hydrochloric acid was added to adjust the pH to 2 to dissolve the calcium phosphate, and then filtered, washed with water and dried to obtain polymer particles (toner particles).

The obtained polymer particles contained 8.4 parts of a monoester wax per 100 parts of the binder resin, and the wax was converted to a shell resin by a tomography method of the polymer particles using a transmission electron microscope (TEM). A core-shell structure encapsulated in the layer was confirmed.

The binder resin of the polymer particles obtained was S
The P value was 19 and the Tg was 60 ° C.

To 100 parts of the obtained polymer particles (toner particles), the following three external additives were externally added, and after the external addition, coarse particles were removed with a 330-mesh sieve. Of cyan toner No. 1 was obtained. Cyan toner No. 1 had a weight average particle size of 7.3 μm and SF-1 was 108.

(1) First hydrophobic silica fine powder 0.3
Part: BET specific surface area 170 m ² / g Number average particle diameter 12 nm 100 parts of silica fine powder subjected to hydrophobic treatment with 20 parts of hexamethyldisilazane in the gas phase.

(2) Second hydrophobic silica fine powder 0.7
Part: BET specific surface area 70 m ² / g Number average particle size 30 nm 100 parts of silica fine powder subjected to hydrophobic treatment with 10 parts of hexamethyldisilazane in the gas phase.

(3) Hydrophobic titanium oxide fine powder 0.4 part: BET specific surface area 100 m ² / g Number average particle diameter 45 nm Hydrophobic with 10 parts of isobutyltrimethoxysilane in an aqueous medium with respect to 100 parts of titanium oxide fine powder Which has been converted.

Production Example 2 of Toner Magenta polymer particles (toner particles) were obtained in the same manner as in Production Example 1 of the toner except that a quinacridone pigment was used instead of the copper phthalocyanine pigment. Three types of external additives were externally added to the obtained polymer particles in the same manner as in Example 1 to obtain a negatively charged magenta toner No. 1 2 was prepared. The magenta toner had a weight average particle size of 7.3 μm and SF-1 was 108.

Toner Production Example 3 Instead of the copper phthalocyanine pigment, C.I. I. Pigment Yellow 180 except that Pigment Yellow 180 was used.
Polymer particles of yellow color (toner particles) were obtained in the same manner as described above. The external additive 3 was added to the obtained polymer particles in the same manner as in Example 1.
Seeds are externally added, and the yellow toner No. 3 was prepared. The yellow toner has a weight average particle diameter of 7.2 μm,
F-1 was 109.

Production Example 4 of Toner Black polymer particles (toner particles) were obtained in the same manner as in Production Example 1 of the toner except that carbon black was used instead of the copper phthalocyanine pigment. Three kinds of external additives were externally added to the obtained polymer particles in the same manner as in Example 1 to obtain a black toner No. 4 was prepared. The black toner had a weight average particle size of 7.4 μm and SF-1 of 108.

[Example 1] 92 parts of magnetic carrier I and cyan toner No. 18 parts were mixed with a V-type mixer so that the toner concentration became 8%, to obtain a two-component developer 1.

Using 100 g of this two-component developer, a commercially available digital copying machine GP5 was used as an image forming apparatus.
5 (manufactured by Canon Inc.) was modified so that the developing device and the charging device of FIG. 1 could be inserted, and the device using the developing bias of FIG. 2 was used. Modified to a configuration in which the roller was changed to a coated roller and the oil application mechanism was removed, ferrite particles were used as a charging member, and an original document with an image area of 25% was used. / 5
% (N / L), 32.5 ° C./90% (H / H), and a 10,000-sheet paper passing test was performed in each environment, and the evaluation was made based on the following evaluation method. Good results were obtained as shown in Tables 3 and 4.

Further, the two-component developer 1 was allowed to stand for one week and one month in each of the N / L and H / H environments, and a paper passing test was performed in each environment in the same manner as described above. The evaluation was based on the method. As shown in Table 4, good results were obtained.

(1) Image Density: The image density was measured using a Macbeth Densitometer RD918 type (Macbeth Densitometer) equipped with an SPI filter.
et RD918manufactured by
Macbeth Co. 2) on plain paper using
Five solid patches of 0 ° (original original density 1.5) were formed at five locations, and measured as an average image density.

(2) Carrier adhesion: A solid white image was formed, and a portion of the photosensitive drum between the developing section and the cleaner section was sampled with a transparent adhesive tape in close contact with it, and sampled for 5 cm.
The number of magnetic carrier particles adhering on the photosensitive drum in a size of 5 cm is counted, and the number of adhering carrier particles per 1 cm ² is calculated. ◎: less than 5 pieces / cm ² ：: less than 5 pieces / cm ² Δ: less than 10 pieces / cm ² ×: more than 20 pieces / cm ²

(3) Fog The average reflectance Dr (%) of plain paper before image formation was measured using a reflectometer (“REFLECTOME” manufactured by Tokyo Denshoku Co., Ltd.).
TER MODEL TC-6DS "). On the other hand, a solid white image was formed on plain paper, and the reflectance Ds (%) of the solid white image was measured. Fog (%)
Is calculated from the following equation: Fog (%) = Dr (%)-Ds (%) ◎: less than 0.4% ○: 0.4 to less than 0.8% △: 0.8 to less than 1.2% ×: 1.2% or more

(4) Solid Uniformity The difference between the maximum and minimum patch densities at the five locations used in (1) was determined.

Example 2 The procedure of Example 1 was repeated except that the magnetic carrier II was used. As shown in Tables 3 and 4, good results were obtained as in Example 1.

Example 3 Example 1 was repeated except that magnetic carrier III was used.
As shown in Tables 3 and 4, good results were obtained as in Example 1.

Example 4 The procedure of Example 1 was repeated except that the magnetic carrier IV was used. As shown in Tables 3 and 4, good results were obtained as in Example 1.

Example 5 The same procedure as in Example 1 was carried out except that the magnetic carrier V was used.
As shown in Examples 4 and 4, good results were obtained as in Example 1.

Example 6 The procedure of Example 1 was repeated except that the magnetic carrier VI was used. As shown in Tables 3 and 4, good results were obtained as in Example 1.

Example 7 The procedure of Example 1 was repeated, except that the magnetic carrier X was used.
As shown in FIGS. 4 and 5, better results were obtained in fog than in Example 1. This is presumably because the use of high-resistance nonmagnetic hematite resulted in a further increase in the surface resistance of the carrier, and no disturbance of via-leaf and latent image charge during development.

Example 8 The same procedure as in Example 1 was carried out except that the magnetic carrier XI was used. As shown in Tables 3 and 4, better results were obtained in fog than in Example 1. Was. This is because the residual magnetic flux density is very small, the fluidity of the carrier is further improved, and high resistance non-magnetic hematite is used, so the surface resistance is further increased, the via leaf during development, disturbance of latent image charge is reduced. It is presumed that they have disappeared.

Example 9 The procedure of Example 1 was repeated, except that the magnetic carrier XII was used.
Although the fog slightly deteriorated at 10,000 sheets, good results were obtained as shown in Tables 3 and 4. This is presumed to be because the spent resistance of the toner was slightly reduced because the silicone resin was not coated.

Example 10 The same procedure as in Example 1 was carried out except that the magnetic carrier XIII was used, and the fog was slightly deteriorated at 10,000 sheets.
And 4, good results were obtained. This is presumably because, because γ-aminopropyltrimethoxysilane was not used, the adhesion of the coating resin was slightly reduced, and a sufficiently uniform coating on the carrier surface was not achieved.

Comparative Example 1 The procedure of Example 1 was repeated, except that the magnetic carrier VII was used.
As shown in Tables 3 and 4, fog and carrier adhesion were recognized from the beginning, and at 10,000 sheets, solid uniformity deteriorated and fog also deteriorated. This is presumed to be because the use of magnetite containing no P component increased the σ _r of the carrier and deteriorated the miscibility with the toner.

[Comparative Example 2] The same procedure as in Example 1 was carried out except that the magnetic carrier VIII was used. As shown in Tables 3 and 4, fog and carrier adhesion were recognized from the beginning, and the time point of 10,000 sheets was observed. As a result, solid uniformity deteriorated and fog also deteriorated. This is because when producing hydrophobic iron oxide,
It is presumed that the addition of sodium hexametaphosphate after the generation of the magnetite particles did not decrease the σ _r of the carrier and deteriorated the mixing property with the toner.

Comparative Example 3 The procedure of Example 1 was repeated, except that the magnetic carrier IX was used. As shown in Tables 3 and 4, carrier adhesion occurred from the beginning, and image evaluation was difficult. So the evaluation was stopped. This is presumably because the magnetite particles were not subjected to the hydrophobizing treatment, so that the dispersion of the magnetite became uneven and many of them were released from the carrier particles.

[0228]

[Table 3]

[0229]

[Table 4]

Example 11 Toner No. 1 to No. 4
Using the four color toners, a developer was prepared in the same manner as in Example 1, and using the image forming apparatus shown in FIG. 3, images were formed in the order of yellow, magenta, cyan, and black. As a result, good results were obtained as in Example 1.

[0231]

According to the present invention, a high-resolution, high-definition color image can be obtained over a long period of time, and the residual magnetic flux density is small. The present invention can provide a magnetic fine particle-dispersed resin carrier and a two-component developer which are excellent in toner quality and are less likely to cause toner spent.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating a preferred example of an image forming method of the present invention.

FIG. 2 is a diagram showing an alternating electric field used in Example 1.

FIG. 3 is a schematic explanatory view showing an example of a full-color image forming method.

FIG. 4 is a schematic diagram of a cell used for measuring a volume resistance value.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrostatic image carrier (photosensitive drum) 4 developing device 11 developer carrier (developing sleeve) 12 magnet roller 13, 14 developer transport screw 15 regulating blade 17 partition 18 replenishing toner 19 developer 19 a toner 19 b carrier 20 replenishing Port 21 Magnet roller 22 Transport sleeve 23 Magnetic particles 24 Laser beam 25 Transfer material (recording material) 26 Bias applying means 27 Transfer blade 28 Toner density detection sensor 61a Photosensitive drum 62a Primary charger 63a Developing device 64a Transfer blade 65a Replenishing toner 67a Laser light 68 Transfer material carrier 69 Separation charger 70 Fixer 71 Fixing roller 72 Pressure roller 73 Web 75, 76 Heating means 79 Transfer belt cleaning device 80 Driving roller 81 Belt driven roller 82 Bell G Static eliminator 83 Registration roller 85 Toner concentration detection sensor 121 Lower electrode 122 Upper electrode 123 Insulator 124 Ammeter 125 Voltmeter 126 Power supply 127 Sample 128 Guide ring

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kenichi Nakayama 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Shinya Yanauchi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Ryoichi Fujita 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term (reference) in Canon Inc. 2H005 AA06 AA08 AB06 BA03 BA11 CA14 CA26 CA28 CB03 EA02 EA05 EA07 FA01

Claims (18)

[Claims] 1. A magnetic fine particle-dispersed resin carrier formed of composite particles having at least lipophilic magnetic fine particles and a binder resin, wherein the magnetic fine particles are expressed in terms of P with respect to Fe. A magnetic fine particle-dispersed resin carrier containing 0.03 to 5.0% by weight of a phosphorus compound. 2. A carrier having a residual magnetic flux density of 9 Am ² /
2. The magnetic fine particle-dispersed resin carrier according to claim 1, wherein the weight is not more than kg. 3. The resin carrier according to claim 1, wherein said magnetic fine particles are magnetite particles. 4. The resin carrier according to claim 1, wherein the lipophilic treatment agent is a silane coupling agent. 5. The resin carrier according to claim 1, wherein the carrier contains magnetite and a nonmagnetic inorganic compound. 6. The magnetic fine particle-dispersed resin carrier according to claim 1, wherein the composite particles are obtained by a polymerization method. 7. The magnetic fine particle-dispersed resin carrier according to claim 1, wherein the surface of the composite particles is treated with a coupling agent. 8. The resin carrier according to claim 7, wherein the coupling agent is a silane coupling agent having an amino group. 9. A two-component developer containing at least a toner having toner particles, an external additive, and a magnetic fine particle-dispersed resin carrier, wherein the toner has a weight average particle diameter of 3 to 9 μm and 40% by weight of wax. Wherein the carrier is formed of composite particles having at least lipophilic magnetic fine particles and a binder resin. 03-
A two-component developer containing 5.0% by weight of a phosphorus compound. 10. The carrier has a residual magnetic flux density of 9 Am ^2.
/ Kg or less. 11. The two-component developer according to claim 9, wherein said magnetic fine particles are magnetite particles. 12. The two-component developer according to claim 9, wherein said lipophilic treatment agent is a silane coupling agent. 13. The method according to claim 9, wherein said carrier contains magnetite and a nonmagnetic inorganic compound.
2. The two-component developer according to any one of 2. 14. The two-component developer according to claim 9, wherein the composite particles are obtained by a polymerization method. 15. The two-component developer according to claim 9, wherein the surface of the composite particles is treated with a coupling agent. 16. The method according to claim 1, wherein the coupling agent is a silane coupling agent having an amino group.
6. The two-component developer according to 5. 17. The external additive has a number average particle size of 3 to 100 n.
17. The two-component developer according to claim 9, wherein m is m. 18. The two-component developer according to claim 9, wherein said toner particles are obtained by a polymerization method.