JPH07113788B2 - Two-component developer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a two-component developer for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like.

[Conventional technology]

It is well known in the art to image and develop the surface of a photoconductive material by electrostatic means.

That is, many methods are known, such as U.S. Pat.No. 2,297,691, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-24748, but generally, a photoconductive substance is used and various methods are used. An electric latent image is formed on the photoconductor, and then a very finely ground electrophotographic material called toner is attached to the latent image to form a toner image corresponding to the electrostatic latent image.

Then, if necessary, the toner is transferred onto the surface of an image support such as paper, and then fixed by heating, pressurizing or solvent vapor to obtain a copy. In addition, when there is a step of transferring the toner image, a step for removing the residual toner is usually provided.

The developing method visualized using an electric latent image toner is, for example, a powder cloud method described in U.S. Pat.No. 2,221,776, a cascade developing method described in No. 2,618,552, and 2,874,063. A magnetic brush method described in Japanese Patent No. 3,909,258 and a method using a conductive magnetic toner described in No. 3,909,258 are known.

As the toner applied to these developing methods, generally, a thermoplastic resin in which a colorant is mixed and dispersed and then pulverized is used. Polystyrene resin is the most common thermoplastic resin, but polyester resin, epoxy resin, acrylic resin, urethane resin, etc. are also used. Carbon black is most widely used as the colorant, and iron oxide-based black magnetic powder is often used in the case of magnetic toner. In the case of a system using a so-called two-component developer, the toner is usually used by being mixed with carrier particles such as glass beads and iron powder.

The toner image on the final copy image forming member such as paper is permanently fixed on the support by heat, pressure or the like. Traditionally,
This fixing process is often performed by heat.

When a step of transferring a toner image is included, usually,
Steps are provided for removing residual toner on the photoreceptor.

In recent years, the development from mono-color copying to full-color copying is rapidly progressing in copying machines and the like, and two-color copying machines and full-color copying machines are being studied and put into practical use. For example, there are reports of color reproducibility and gradation reproducibility such as "Electrophotographic Society Journal" Vol22, No.1 (1983) and "Electrophotographic Society Journal" Vol25, No.1, P52 (1986).

However, the full-color electrophotographic images currently in practical use are not always satisfactory for people who are not immediately compared with the actual products such as televisions, photographs, and color prints, and for those who can see the color images that are more beautifully processed than the actual products. It is not possible.

Color image formation by full-color electrophotography is generally 3
All the colors are reproduced by using the color toners of the three primary colors of yellow, magenta, and cyan.

The method is to first form the electrostatic latent image on the photoconductive layer by passing the light from the original through the color-separating light-transmitting filter, which has a complementary color relationship with the color of the toner, and then developing and transferring the toner onto the support. Hold it. Repeat this process multiple times,
The final full-color image is obtained by superposing the toner on the same support while aligning the resist races and then fixing the toner once.

Generally, in the case of a so-called two-component developing method in which the developer is composed of a toner carrier, the developer causes the toner to be charged to a required charge amount and charge polarity by friction with the carrier, and electrostatically attracted using electrostatic attraction. The image is developed, and therefore, in order to obtain a good visible image, it is necessary that the toner has good triboelectric chargeability, which is mainly determined by the relationship with the carrier.

In response to the problems described above today, the search for carrier core agents and carrier coating agents and the optimization of the coating amount, or the examination of charge control agents and fluidity-imparting agents added to toner, and the improvement of the base binder are all Many studies have been conducted to achieve excellent triboelectric chargeability in all materials constituting the developer.

For example, as a technique for adding a charging auxiliary agent such as chargeable fine particles to a toner, Japanese Patent Publication No. 52-32256 and Japanese Patent Laid-Open No. 56-643 are known.
No. 52 discloses a technique in which a fine resin powder having a polarity opposite to that of a toner is added to a developer, and Japanese Patent Application Laid-Open No. 61-160760, a fluorine-containing compound is added to a developer to obtain stable triboelectrification. However, many charging aids are still being developed today.

Further, various methods have been devised as a method of adding the charging auxiliary agent as described above. For example, a method of adhering the toner particles to the surface of the toner particles by an electrostatic force between the toner particles and the charging auxiliary agent or a Van der Waals force is generally used, and stirring, a mixer or the like is used. However, in this method, it is not easy to uniformly disperse the additives on the surface of the toner particles, and the additives are not attached to the toner particles and the additives become aggregates, so that the existence of the additives in a so-called free state is not detected. It is difficult to avoid. This tendency becomes more remarkable as the specific electric resistance of the charging aid is larger and the particle size is smaller. In such a case, the performance as a developer is affected. For example, the amount of triboelectricity of the toner becomes unstable, the image density is not constant, and the image has a lot of fog.

Alternatively, when continuous copying or the like is carried out, there is a problem that the content of the charging aid changes and the initial image quality cannot be maintained.

As another addition method, there is a method of previously adding the charging auxiliary together with the binder resin and the colorant at the time of manufacturing the toner. However, it is not easy to make the charge control agent uniform, and it is the toner near the surface of the toner particles that substantially contributes to the chargeability, and the charge auxiliary agent and charge control agent present inside the particles have the chargeability Therefore, it is not easy to control the addition amount of the charging aid and the dispersion amount on the surface. Further, even in the toner obtained by such a method, the triboelectric charge amount of the toner is unstable and it is not possible to easily obtain a toner satisfying the developer characteristics as described above. The reality is that no product of satisfactory quality has been obtained.

Further, in recent years, demands for high-definition and high image quality of copying machines have been increasing in the market, and in the technical field, an attempt has been made to achieve high image quality color by reducing the particle size of toner. As the diameter becomes smaller, the surface area per unit weight increases and the amount of electrification of the toner tends to increase, and there is a concern that the image density will be low and the durability will deteriorate. In addition, since the amount of electrification of the toner is large, the adhesion between the toners is strong, the fluidity is lowered, and problems occur in stability of toner replenishment and tribo application to the replenishment toner.

Further, since the color toner does not contain a magnetic substance or a conductive substance such as carbon black, there is no portion for leaking charge, and the amount of charge generally tends to be large. This tendency is more remarkable when a polyester binder having high charging performance is used.

Further, especially in color toners, the following characteristics are strongly desired.

(1) The fixed toner needs to be in a state of almost completely melted so that the shape of the toner particles cannot be discriminated so as not to diffusely reflect light and prevent color reproduction.

(2) It must be a colored toner having transparency that does not interfere with the toner layers of different tones below the toner layer.

(3) Each of the constituent toners must have well-balanced hue and spectral reflection characteristics and sufficient saturation.

From this point of view, many studies on binder resins have been made, but a toner satisfying all the above characteristics has not been developed yet. Today, polyester resins are often used as binder resins for color in the technical field, but toners made of polyester resins are generally susceptible to temperature and humidity, and have excessive charge amount under high humidity and high humidity. There is an urgent need to develop a color toner that has a stable charge amount even in a wide range of environments due to the problem that the charge amount is insufficient.

[Problems and Actions to be Solved by the Invention]

An object of the present invention is to provide a two-component developer for developing an electrostatic charge image, which solves the above problems.

That is, an object of the present invention is to provide a two-component developer which has a stable triboelectric charging property under various environments such as changes in wet temperature and which can give clear image characteristics without fog. is there.

Another object of the present invention is to provide a two-component developer capable of faithfully reproducing a latent image formed on a photoconductor and showing image durability.

Another object of the present invention is to provide a two-component developer having a carrier that has a stable charge imparting ability and can have a long life.

Still another object of the present invention is to provide a two-component developer having a carrier that does not adhere to the drum, is durable, and has good toner separation.

Still another object of the present invention is to provide a two-component developer capable of more positively preventing excessive charging of the toner and providing a good image even under various environments.

[Means and Actions for Solving the Problems]

The present invention is a two-component developer having a color toner and a carrier having at least non-magnetic colorant-containing resin particles and an external additive, wherein the external additive has a particle size of 20 to 200 mμ and a specific electric resistance of 10 ⁶ to The color toner has a volume average particle size of 6 to 10 μm and has an organic resin particle of 10 ¹⁴ Ωcm and has a polarity opposite to that of the nonmagnetic colorant-containing resin particle when frictionally charged with the carrier. And containing 15 to 40% by number of non-magnetic colorant-containing resin particles having a particle size of 5 μm or less, and 0.1 to 5.0% by volume of non-magnetic colorant-containing resin particles having a particle size of 12.7 to 16.0 μm. A non-magnetic colorant-containing resin particle having a particle size of 16 μm or more has a particle size distribution of 1.0 vol% or less.

Further, the present invention relates to a two-component developer, wherein the above-mentioned carrier is coated with 0.05 to 10% by weight of a resin based on the weight of the carrier core material and has a weight average particle diameter of 25 to 65 μm.

Furthermore, in the present invention, the above-mentioned carrier core material is made of Cu of 98% or more.
-Zn-Fe (metal composition ratio (5 to 20): (5 to 20): (30 to 8)
The present invention relates to a two-component developer, which is a ferrite having the composition of 0)).

Furthermore, the present invention provides that the carrier and the non-magnetic colorant-containing resin particles have triboelectric charge amounts of A _L at 15 ° C./10% RH and A _H at 30 ° C./80% RH. When the triboelectric charge of resin particles is B _L under 15 ℃ / 10% RH and _BH under 30 ℃ / 80% RH, the following conditions are 1.1 ≦ ｜ A _L / A _H ｜ ≦ 3.0 1.2 ≦ ｜ B _L / B _H | ≦ 8.0 1.0 ≦ | (B _L / B _H ) / (A _L / A _H ) | ≦ 3.0 The two-component developer according to claim 1, characterized in that:

As a result of intensive studies on the environmental stability of the charging property of a two-component developer for developing an electrostatic image, the present inventors have found that the particle size of the non-magnetic coloring agent-containing resin particles as an external additive has a particle size of 20%.
~ 200mμ, specific electric resistance 10 ⁶ ~ 10 ¹⁴ Ωcm added organic resin particles, the developer has excellent stability of electrification under various environments such as temperature and humidity changes, providing a good image without fog. I found that I would do it.

The reason is that the above-mentioned organic resin particles neutralize the charge gap caused by excessive rubbing between the non-magnetic colorant-containing resin particles and the carrier used in the present invention.

Furthermore, by adding the organic resin particles, the rise of charging of the toner is promoted, and very stable charging characteristics are achieved from the initial stage.

The reason for this is not clear yet, but it is presumed as follows. That is, the organic resin particles are strongly attracted and charged to the carrier side rather than the non-magnetic colorant-containing resin particles at the initial stage of rubbing between the carrier and the toner. Therefore, the rising of charging of the resin particles containing the non-magnetic colorant having the opposite polarity is promoted. On the other hand, once it stands up, it is more strongly attracted to the non-magnetic colorant-containing resin particles than the carrier,
The function of neutralizing excessive charge works, and therefore, the toner of the constitution of the present invention can maintain the rising of charge and the saturated charge amount level in a good and stable manner in various environments.

In the two-component developer of the present invention in order to make the above-mentioned action more effective, the particle size of the organic resin particles is 20 to 200 mμ, preferably 30 to 150 mμ, and the specific electric resistance is 10 ⁶ to 10 ¹⁴ Ωcm. is there.

If the particle size is smaller than the above range, the organic resin particles may adhere too strongly to the non-magnetic colorant-containing resin particles or may be embedded, or the organic resin particles may become aggregates and become free. As a result, the above effects disappear. On the other hand, if it is larger than the above range, the dispersion becomes non-uniform,
It will be released and the effect will disappear. Further, if the specific electric resistance is larger than 10 ¹⁴ Ωcm, the cohesiveness of the organic resin particles is increased, the mixing property is lowered, and at the same time, the organic resin particles themselves are charged and fly to the non-image area together with the toner to cause fog. However, the harmful effects such as the carrier spent will occur. On the other hand, if it is less than 10 ⁶ Ωcm, the toner charge amount is reduced especially under high temperature and high humidity, resulting in fog due to toner scattering or a leak phenomenon during development, resulting in image defects.

In the present invention, it is preferable that the organic resin particles are contained in an amount of 0.1 to 5.0% by weight based on the non-magnetic colorant-containing resin particles in order to surely exhibit the performance and obtain stable negative chargeability.

When the content of the organic resin particles is less than 0.1% by weight, the negative chargeability cannot be stably obtained, and when it is more than 5.0% by weight, the miscibility is poor and the charging becomes unstable. There is a problem.

The organic resin particles of the present invention are also suitable when the toner has a small diameter.

That is, when the diameter of the toner is reduced, there are problems that the contact points between the toner and the carrier increase, the carrier spent easily occurs, the contact points between the toner and the toner increase, and the toner blocking easily occurs.

On the other hand, spherical organic resin particles having an appropriate size of 20 to 200 mμ serve as a good spacer, and the above-mentioned problems do not occur and a good effect is exerted. For toner blocking,
It is even more effective if the material of the reverse polarity resin particles has a glass transition temperature (Tg) higher than that of the resin used for the resin particles containing the non-magnetic colorant.

As described above, there are some examples of adding resin particles of opposite polarity to the toner. For example, JP-A-54-45135 and
Japanese Examined Patent Publication No. 52-32256 proposes addition of colorless resin particles smaller than the toner particle size.

However, in these examples, the toner and the resin particles of opposite polarity behave separately, and the toner adheres to the latent image portion during development, whereas the resin particles of opposite polarity adhere to the background portion.

That is, the reverse polarity resin particles have a function of promoting the charging of the toner. However, in the present invention,
It is characterized by using organic resin particles of opposite polarity, which are sufficiently smaller than the toner particle size, and finally strongly adhering to the non-magnetic colorant-containing resin particles so that they behave together.

Further, resin particles of opposite polarity have been conventionally used for the purpose of assisting charging of magnetic toner, which is difficult to have a large charge amount. On the other hand, the present invention is characterized in that it is positively used for non-magnetic color toners that tend to be excessively charged.

More recently, as described in JP-A-1-113767, it has been proposed to use silica and organic resin particles in combination, but this is used to weaken the adhesion between the drum and the toner. However, it is different from the color toner used in the two-component developer of the present invention.

Furthermore, Japanese Examined Patent Publication Nos. 2-3173, 3174, and 3175
The average particle size in the developer is 0.05.
It is known to mix fine powder made of resin having a size of -5 μm (5-500 mμ).

However, as described in the publication, these fine powders are generally composed of (acrylic acid ester monomer, methacrylic acid ester monomer, styrene-based monomer, nitrogen-containing addition polymerizable monomer, polymerizable unsaturated carboxylic acid monomer). It is only composed of a resin (consisting of a homopolymer or a copolymer obtained from one or more kinds of selected monomers), and the specific electric resistance of the fine powder is 10 ¹⁵ or more as is generally known. Therefore, as described above, there are problems such as deterioration of mixing property, occurrence of fog, and carrier spent.

On the other hand, the reverse polarity organic resin particles of the present invention include, for example, a polymerization initiator in which a specific dispersion stabilizer such as an amphoteric surfactant is contained in the particles, or a hydrophilic group is contained as a branch. The specific electric resistance may be lowered to 10 ⁶ to 10 ¹⁴ Ωcm by making at least the surface of the particles hydrophilic by polymerizing with, but the specific electric resistance is not limited to this and other methods may be used. The resistance is 10 ⁶ to 10 ¹⁴ Ωc
May be m.

In the present invention, the frictional charge amount of carrier and the non-magnetic colorant-containing resin particles for the purpose of neutralizing the toner charge positively is under _{15 ℃ / 10% RH A L} , 30 ℃ / 80% When the frictional charge of A _H under the RH and the above organic resin particles is B _L under 15 ° C / 10% RH and B _H under 30 ° C / 80% RH, the following conditions 1.1 ≦ ｜ A _L / A _H | ≦ 3.0 1.2 ≦ | B _L / B _H | ≦ 8.0 1.0 ≦ | (B _L / B _H ) / (A _L / A _H ) | ≦ 3.0 is preferable.

If each value is not within the above range, the neutralization effect is insufficient, and the image density is lowered under low humidity, and the triboelectric charge amount is excessively reduced under high humidity, causing toner scattering and causing problems such as fog.

The particle size of the organic resin particles in the present invention is APA-50.
It is the volume average particle diameter measured by 0 type (manufactured by Horiba Ltd.).

The monomer constituting the reverse polarity organic resin particles used as an additive in the present invention is not particularly limited,
It is necessary to select it in consideration of the chargeability of the toner. The following monomers may be mentioned as specific examples of the addition-polymerizable monomer that can be used in the present invention.

That is, styrene and its derivatives, for example, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene, alkylstyrene such as octylstyrene, fluorostyrene, chlorostyrene. Halogenated styrene such as styrene, bromostyrene, dibromostyrene, iodostyrene, nitrostyrene, acetylstyrene,
Methoxy styrene etc. are mentioned.

Further, addition-polymerizable unsaturated carboxylic acids, that is, addition polymerization such as acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid, α-methylcrotonic acid, α-ethylcrotonic acid, isocrotonic acid, tiglic acid, and ungeric acid. And unsaturated polymerizable aliphatic aliphatic dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid and dihydromuconic acid.

Also, a metal chloride of these carboxylic acids can be used, and this metal chloride can be carried out after completion of the polymerization.

Further, esterification products of the addition-polymerizable unsaturated carboxylic acid with an alcohol such as an alkyl alcohol, a halogenated alkyl alcohol, an alkoxyalkyl alcohol, an aralkyl alcohol and an alkenyl alcohol may be mentioned. And, as specific examples of the alcohol, methyl alcohol, ethyl alcohol, propyl alcohol,
Alkyl alcohols such as butyl alcohol, amyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, dodecyl alcohol, tetradecyl alcohol, hexadecyl alcohol; halogenated alkyl alcohols obtained by partially halogenating these alkyl alcohols; methoxyethyl alcohol , Alkoxyalkyl alcohols such as ethoxyethyl alcohol, ethoxyethoxyethyl alcohol, methoxypropyl alcohol and ethoxypropyl alcohol; aralkyl alcohols such as benzyl alcohol, phenylethyl alcohol and phenylpropyl alcohol; alkenyls such as allyl alcohol and crotonyl alcohol. Examples include alcohol.

Further, amides and nitriles derived from the addition-polymerizable unsaturated carboxylic acid; ethylene, propylene, butene,
Aliphatic monoolefins such as isobutylene; vinyl chloride, vinyl bromide, vinyl iodide, 1,2-dichloroethylene, 1,2-dibromoethylene, 1,2-diiodoethylene,
Halogenated aliphatic olefins such as isopropenyl chloride, isopropenyl bromide, allyl chloride, allyl bromide, vinylidene chloride, vinyl fluoride, vinylidene fluoride; 1,3-butadiene, 1,3-pentadiene, 2-methyl- Examples thereof include conjugated diene-based aliphatic diolephins such as 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2,4-hexadiene and 3-methyl-2,4-hexadiene.

Further, vinyl acetates, vinyl ethers; nitrogen-containing vinyl compounds such as vinylcarbazole, vinylpyridine, vinylpyrrolidone and the like can be mentioned.

As the organic resin particles according to the present invention, those obtained by polymerizing one kind or two or more kinds of these monomers can be used.

The reverse polarity organic resin particles used in the present invention are not limited to using only one type, and a plurality of types can be used in combination.

Further, as a method for producing organic resin particles of opposite polarity used in the present invention, spray drying method, suspension polymerization method, emulsion polymerization method, soap-free polymerization method, seed polymerization method, mechanical pulverization method, etc. to produce spherical fine particles. Any method that can be used can be used. Among these, particularly suitable is a soap-free polymerization method which does not hinder the charging property of the toner and has little environmental fluctuation of the specific electric resistance value because there is no residual emulsifier, but is not particularly limited. Absent.

The opposite polarity organic resin particles may be subjected to particle surface treatment, if necessary. As the method of surface treatment, a method of surface-treating a metal such as iron, nickel, cobalt, copper, zinc, gold or silver by a vapor deposition method or a plating method, or a metal oxidation such as the above-mentioned metal or magnetic material, conductive zinc oxide, etc. A method of immobilizing a substance or the like by ion adsorption or external addition, a pigment or a dye, and a triboelectrically chargeable organic compound such as a polymer resin may be supported by coating or external addition.

Further, the molecular weight distribution of the organic resin particles used in the present invention is required to have a peak molecular weight in the range of 10,000 to 5,000,000, and preferably in the range of 20,000 to 1,000,000. If the peak molecular weight is more than 5,000,000, the fixability of the color toner is adversely affected, and if it is less than 10,000, problems such as contamination and poor blocking resistance occur.

In addition to the above-mentioned organic resin particles, a flow improver may be added to the developer of the present invention. As the flow improver, it is particularly preferable to use a hydrophobic inorganic oxide because it acts to promote the function of the organic resin particles in terms of chargeability and fluidity. In order to sufficiently exert its action, it is desired that the BET specific surface area is 80 m ² / g or more, and particularly when it is 150 m ² / g or more, the above-mentioned action can be caused more remarkably. it can.

As the hydrophobic inorganic oxide, it is particularly preferable to use a treated silica fine powder obtained by subjecting a silica fine powder produced by vapor-phase oxidation of a silicon halogen compound to a hydrophobic treatment. Among the treated silica fine powders, those obtained by treating the silica fine powders so that the hydrophobicity measured by the methanol titration test has a value in the range of 30 to 80 are particularly preferable.

As a method of hydrophobizing, it is imparted by reacting with silica fine powder or chemically treating with an organic silicon compound which physically adsorbs.

As a preferred method, silica fine powder produced by vapor phase oxidation of a silicon halogen compound is treated with an organosilicon compound.

Examples of such organosilicon compounds include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane,
Allylphenyldichlorosilane, benzyldimethylchlorosilane, brommethyldimethylchlorosilane, α-chloroethyltrichlorosilane, ρ-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate , Vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane,
Hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane and 2 to 12 siloxane units per molecule, one for each terminally located unit Examples include dimethylpolysiloxane containing a hydroxyl group bonded to Si.
These are used alone or as a mixture of two or more.

Commercially available products include Taranox-500 (Tarco) and Aerosil R-972 (Japan Aerosil). The amount added is 0.3 to the colorant-containing resin particles
It is 2% by weight.

This addition amount is also related to the particle size distribution of the non-magnetic colorant-containing resin particles described below, but if it is less than 0.3% by weight, it is difficult to achieve appropriate fluidity, and if it is 2% by weight or more, toner scattering and fog may occur. Harm is likely to occur.

The toner according to the present invention may be blended with a charge control agent in order to stabilize the charging characteristics. At that time, a colorless or pale color charge control agent that does not affect the color tone of the toner is preferable. Examples of the negative charge control agent at that time include organic metal complexes such as metal complexes of alkyl-substituted salicylic acid (eg, chromium complex or zinc complex of di-tert-butylsalicylic acid). When the negative charge control agent is blended in the toner, it is 0.1 to 10 parts by weight, preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the binder resin.
It is recommended to add 8 parts by weight.

When a two-component developer is prepared by mixing the toner according to the present invention and a carrier, the mixing ratio is usually 2 to 10% by weight, preferably 3 to 9% by weight as the toner concentration in the developer. Results are obtained. Toner concentration is 2% by weight
If it is less than 10% by weight, the image density is too low to be practical, and if it exceeds 10% by weight, fog or in-machine scattering is increased and the useful life of the developer is shortened.

As the colorant used in the present invention, a known facial dye amount, for example, phthalocyanine blue, induslen blue, pekotsk blue, permanent red, lake red, rhodamine lake, Hansa yellow, permanent yellow, benzidine yellow, etc. can be widely used. it can.
The content thereof is 12 parts by weight or less, preferably 0.5 to 9 parts by weight, based on 110 parts by weight of the binder resin so as to sensitively reflect the transparency of the OHP film.

If necessary, the toner of the present invention may be mixed with additives within a range that does not impair the characteristics of the toner. Examples of such additives include polytetrafluoroethylene, zinc stearate, and polyvinylidene fluoride. And a fixing aid (for example, low molecular weight polyethylene, low molecular weight polypropylene, etc.).

In the production of the toner of the present invention, a method in which the constituent materials are well kneaded by a heat kneader such as a hot roll, a kneader or an extruder, and then mechanical pulverization or classification is performed, or a colorant is added to the binder resin solution. A method of obtaining a toner by dispersing materials such as, for example, spray-drying, or by mixing a predetermined material with a monomer that constitutes the binder resin and then polymerizing the emulsion suspension. Each method such as a toner manufacturing method can be applied.

In the present invention, the color toner has a volume average particle size of 6 to
Non-magnetic colorant-containing resin particles having a diameter of 10 μm and a particle diameter of 5 μm or less are contained in an amount of 15 to 40% by number, and 12.7 to 16.0 μm.
Has a particle size distribution in which the non-magnetic colorant-containing resin particles having a particle size of 0.1 to 5.0 volume% are contained, and the non-magnetic colorant-containing resin particles having a particle diameter of 16 μm or more are contained in an amount of 1.0 volume% or less. .

Further, in the present invention, the color toner is 6.35 to 10.1.
Resin particles containing a non-magnetic colorant having a particle size of Here, V: volume% of non-magnetic colorant-containing resin particles having a particle diameter of 6.35 to 10.1 μm N: number% of non-magnetic colorant-containing resin particles having a particle diameter of 6.35 to 10.1 μm dv: total non-magnetic When the particle size distribution satisfies the volume average particle size of the colorant-containing resin particles, the effect is more remarkable and is particularly preferable.

The toner having the above-mentioned particle size distribution can faithfully reproduce the latent image formed on the photoconductor and is excellent in the reproducibility of a minute dot latent image such as a halftone dot and a digital image. An image having excellent gradation and resolution of the light portion is provided. Furthermore, even when copying or printing out is continued, high image quality is maintained, and even in the case of a high density image, good development can be performed with a toner consumption amount smaller than that of the conventional non-magnetic toner. Also, it is advantageous in terms of performance and miniaturization of the copying machine or printer body.

The reason why such effects are obtained in the non-magnetic color toner of the present invention is not always clear, but it is presumed as follows. (In the following description regarding the particle size distribution of toner, "non-magnetic colorant-containing resin particles" are abbreviated as "toner particles.") Conventionally, in non-magnetic color toners, it is difficult to control the charge amount of toner particles of 5 μm or less. It has been considered necessary to positively reduce the fluidity of the toner as a component, the component that scatters the toner and stains the machine, and the component that causes image fog.

However, according to the study by the present inventors, it has been found that toner particles of about 5 μm are an essential component for forming a high quality image.

For example, by using a non-magnetic toner having a particle size distribution ranging from 0.5 μm to 30 μm and a two-component developer having a carrier, the surface potential on the photoconductor is changed, and a large development potential contrast that easily develops many toner particles , To a halftone, and even a small minute dot latent image where only a few toner particles are developed, develop a latent image with a latent image potential changed on the photoconductor, and develop the developed toner particles on the photoconductor. Collected and measured the toner particle size distribution, 8 μm
It was found that there are many toner particles below, especially toner particles of about 5 μm on the latent image of minute dots. That is, 5
When toner particles having a particle size of about μm are smoothly supplied to the development of a latent image on a photoconductor, the toner image is faithful to the latent image, and a truly reproducible image can be obtained without protruding from the latent image. Is.

This is related to the necessity of the presence of toner particles having a particle size of about 5 μm described above, but toner particles having a particle size of 5 μm or less certainly have the ability to faithfully reproduce a minute dot latent image. However, the cohesiveness itself is considerably high, which may impair the fluidity of the non-magnetic toner.

The present inventors attempted to improve fluidity by adding a fluidity improver for the purpose of improving fluidity, but it was difficult to satisfy all the items such as image density, toner scattering, and fog. . Therefore, the present inventor further studied the particle size distribution of the toner, and after containing 15 to 40% by number of toner particles having a particle size of 5 μm or less, 12.7 to 1
It has been found that by containing 0.1 to 5.0 volume% of toner particles of 6.0 μm, the fluidity is further improved and high image quality can be achieved. That is, it is considered that the toner particles in the range of 12.7 to 16.0 μm have appropriately controlled fluidity with respect to the toner particles of 5 μm or less, and as a result, even when copying or printing is continued, high density is achieved. A sharp image having excellent resolution and gradation is provided.

Further, the present inventors have examined the state of the particle size distribution and the developing characteristics, and found that there is a state of existence of the particle size distribution suitable for achieving the most object as shown by the above formula for the toner particles of 6.35 to 10.1 μm. I also found out.

That is, when the particle size distribution is adjusted by general wind force classification, the fact that the value of the above equation is large means that the toner particles of about 5 μm that faithfully reproduce the minute dot latent image increase and that the value is small, on the contrary. It is understood that this indicates that the toner particles of about 5 μm are reduced.

Therefore, when v is in the range of 6 to 10 μm and the above relational expression is further satisfied, better toner fluidity and faithful latent image reproduction are achieved.

Further, for toner particles having a particle size of 16 μm or more, it is preferable that the content is 1.0% by volume or less, and the amount is as small as possible.

This will be described in more detail. Toner particles having a particle size of 5 μm or less are 15 to 40% by number, more preferably 20 to 35% by number of the total number of particles.
Is good. If the number of toner particles having a particle size of 5 μm or less is less than 15% by number, there are few toner particles effective for high image quality.
As the toner is used by continuing to copy or print out, the effective toner particle component decreases,
As shown in the present invention, the balance of the particle size distribution of the color toner deteriorates, and the image quality may gradually deteriorate. or,
If it exceeds 40% by number, the toner particles are likely to aggregate with each other, and the toner particles having a particle size larger than the original particle size are likely to be formed, resulting in a rough image quality, a decrease in resolution, or an edge portion of a latent image. The difference in density between the inside and the inside becomes large, and an image with a slight lack of transparency is likely to be formed.

Further, the toner particles in the range of 12.7 to 16.0 μm are preferably 0.1 to 5.0% by volume, and more preferably 0.2 to 3.0% by volume. If it is more than 5.0% by volume, the image quality will deteriorate and
Unnecessary development, that is, excessive toner overload, causes an increase in toner consumption. On the other hand, if it is less than 0.1% by volume, the image density may decrease due to the decrease in fluidity.

Further, the toner particles having a particle diameter of 16 μm or more are preferably 1.0% by volume or less, more preferably 0.6% by volume or less, and if it is more than 1.0% by volume, not only hindering the reproduction of fine lines, but also in the transfer. Since coarse toner particles of 16 μm or more are projected and present on the thin layer surface of the developed toner particles on the photoconductor, the delicate contact state between the photoconductor and the transfer paper via the toner layer is irregular. As a matter of course, it is likely to cause fluctuations in the transfer conditions and cause a defective transfer image. Also, the volume average diameter of color toner is 6 to 10 μm.
m, preferably 7 to 9 μm, is good, and this value cannot be considered in addition to the above-mentioned constituent elements. If the volume average particle size is less than 6 μm, the problem that the amount of toner adhered on the transfer paper is small and the image density is low is likely to occur in applications where the image area ratio is high such as a graphic image. It is considered that this is due to the same reason as the reason why the internal density is lowered with respect to the edge portion in the latent image described above. If the volume average particle size is 10 μm or more, the resolution is not good, and if the use is continued at the beginning of copying, the image quality is likely to deteriorate.

The toner particle size distribution can be measured by various methods,
In the present invention, a Coulter counter is used.

That is, a Coulter Counter TA-II type (manufactured by Coulter) is used as a measurement position, an interface (manufactured by Nikkaki) and a CX-1 personal computer (manufactured by Canon) that output a number distribution and a volume distribution are connected, and electrolysis is performed. As a liquid, a 1% NaCl aqueous solution is prepared using first grade sodium chloride. As a measuring method, a surfactant, preferably 0.1 to 5 ml of alkylbenzene sulfonate is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and by the Coulter Counter TA-II type,
Using a 100 μm aperture as an aperture, the particle size distribution of particles of 2 to 40 μm was measured based on the number, and the value according to the present invention was determined therefrom.

As the binder substance used in the resin particles containing the non-magnetic colorant of the present invention, various material resins conventionally known as electrophotographic toner binder resins are used.

For example, polystyrene, styrene-styrene copolymers such as styrene-butadiene copolymers, styrene-acrylic copolymers, polyethylene, ethylene-vinyl acetate copolymers, ethylene-copolymers such as ethylene-vinyl alcohol copolymers. , Phenol resin, epoxy resin, acrylic phthalate resin, polyamide resin, polyester resin, maleic acid resin, and the like. In addition, the manufacturing method and the like of each resin are not particularly limited.

Among these resins, the effect of the present invention is great when a polyester resin having a high negative chargeability is used. That is, while polyester-based resins have excellent fixability and are suitable for color toners, on the other hand, they have a strong negative charging ability and tend to be excessively charged, but when the polyester resin is used in the constitution of the present invention, the adverse effects are improved, and excellent toners are obtained. Is obtained.

In particular, (In the formula, R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2
Is ~ 10. ), A bisphenol derivative or a substitution product represented by the formula (1) is used as a diol component, and a carboxylic acid component consisting of a divalent or higher carboxylic acid or an acid anhydride thereof or a lower alkyl ester thereof (for example, fumaric acid, maleic acid, maleic anhydride, A polyester resin obtained by copolycondensation of phthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc.) is more preferable because it has sharp melting characteristics.

In the present invention, an electrically insulating resin is used as the coating resin for the surface of the carrier core material, but it is appropriately selected depending on the toner material and the carrier core material. In the present invention, at least one monomer selected from at least acrylic acid (or its ester) monomer and methacrylic acid (or its ester) monomer in order to improve the adhesion to the surface of the carrier core material. It is necessary to contain. In particular, when polyester resin particles having a high negative chargeability are used as the toner material, it is preferable to use a copolymer with a styrene-based monomer for the purpose of stabilizing the charge, and the copolymerization weight of the styrene-based monomer is preferable. It is preferable that the ratio is 5 to 70% by weight.

The average molecular weight of the copolymer has a number average molecular weight of 10,000 to 10,000 in consideration of the coating uniformity and coating strength of the carrier core material surface.
35,000, preferably 17,000 to 24,000, with a weight average molecular weight
It is preferably 25,000 to 100,000, preferably 49,000 to 55,000.

Examples of the monomer for the coating resin of the carrier core material that can be used in the present invention include styrene-based monomers such as styrene monomer, chlorostyrene monomer, α-methylstyrene monomer, and styrene-chlorostyrene monomer. Are, for example, acrylic acid ester monomers (methyl acrylate monomer, ethyl acrylate monomer, butyl acrylate monomer,
Octyl acrylate monomer, phenyl acrylate monomer, 2-ethylhexyl acrylate monomer, etc., and methacrylic acid ester monomers (methyl methacrylate monomer, ethyl methacrylate monomer, butyl methacrylate monomer, methacrylic acid phenyl monomer), etc. .

In the present invention, it is preferable to coat the carrier core material with the coating resin in the range of 0.05 to 10% by weight. If the coating resin content is less than 0.05% by weight, carriers will adhere to the drum and good development cannot be performed.
If it is more than the above range, the durability of the carrier is lowered, and toner release from the carrier is deteriorated, so that the developing efficiency is apt to be lowered.

The weight average particle size of the carrier is preferably in the range of 25 to 65μ. If the weight average particle size is smaller than 25 μ, the carrier adheres to the drum, and good development cannot be performed. If the weight average particle size is larger than 65 μ, the image quality is likely to be deteriorated due to deterioration of halftone uniformity.

Examples of the carrier core material (magnetic particles) used in the present invention include surface-oxidized or unoxidized iron, nickel, copper, zinc, cobalt, manganese, chromium, metals such as rare earths, and alloys or oxides thereof. Can be used. Moreover, there is no particular limitation in the manufacturing method.

In the present invention, as the above-mentioned carrier core material, 98% or more of Cu-Zn-Fe (metal composition ratio (5 to 20): (5 to 20):
When a ferrite carrier core material composed of (30 to 80) is used, the surface of the carrier core material becomes a moderately smooth surface due to the inclusion of copper, so that the coating thickness of the coating resin becomes uniform and the charging is stabilized and It is particularly preferable because it has a long life.

The measuring method of the present invention will be described below.

(1) Triboelectric charge measurement: The measurement method will be described in detail with reference to the drawings.

FIG. 1 is an illustration of an apparatus for measuring the triboelectric charge amount of toner and external additives. First, a metal measuring container 2 having a 500 mesh screen 3 at the bottom is a mixture of toner and a carrier having a weight ratio of 1:19 for which the triboelectric charge is to be measured, or 1:99 for an external additive. The mixture is placed in a polyethylene bottle having a volume of 50 to 100 ml, and shaken by hand for about 10 to 40 seconds, about 0.5 to 1.5 g of the mixture (developer) is put, and the lid 4 made of metal is placed. Weigh the entire measuring container 2 at this time, W ₁ (g)
And Next, in the suction device 1 (at least the portion in contact with the measurement container 2 is an insulator), suction is performed from the suction port 7 and the air volume control valve 6 is adjusted to set the pressure of the vacuum gauge 5 to 250 mmAq. In this state, the toner (or external additive) is suctioned sufficiently, preferably for 2 minutes to remove the toner (or external additive). At this time, the potential of the electrometer 9 is V (volt). Where 8 is a condenser,
Let the capacity be C (μF). In addition, the total weight of the measuring container after suction is weighed and is W ₂ (g). This toner (or external additive)
The triboelectric charge amount (μc / g) of is calculated by the following formula.

(However, the measurement conditions are 23 ° C. and 60% RH.) The carrier used in the measurement is the ferrite carrier of the present invention having 250-mesh path and 350-mesh order carrier particles of 70 to 90% by weight.

(2) Volume resistivity measurement: A pellet (20 mmφ x 2 to 3 mm thick) was made by pressure molding for 10 t x 30 seconds, and the pellet was left in an environmental chamber at 22 ° C / 55% RH for 24 hours and then volume specific. A resistance measuring device (TR-8601 HIGH MEGAOHM METER manufactured by Takeda Riken) is used to measure the resistance value while changing the electric field, and the value of 1 kv / cm is read by the data plot.

〔Example〕

The present invention will be described in detail below with reference to examples. still,%
All parts and parts are by weight and parts by weight.

Example 1 Polyester resin obtained by condensing propoxylated bisphenol and fumaric acid 100 parts Phthalocyanine pigment 4 parts Chromium complex salt of di-tert-butylsalicylic acid 2 parts was sufficiently premixed by a Henschel mixer and then three-roll mill After being melt-kneaded at least twice with, the mixture was cooled, coarsely pulverized to about 1 to 2 mm with a hammer mill, and then finely pulverized with a fine pulverizer by an air jet system. Further, the obtained finely pulverized product was classified and 2 to 10 μm was selected so as to obtain the particle size distribution of the present invention to obtain non-magnetic colorant-containing resin particles. 100 parts of the obtained colorant-containing resin particles had a particle size of 55 mμ as an external additive and a specific electrical resistance of 3 × 10 ¹⁰ Ωcm as a monomer composition, methyl methacrylate unit and a polymerizable amino acid compound CCH ₂ = CH-N ( Cyan toner was prepared by combining 1.0 parts of acrylic resin particles containing CH ₃ ) -C ₂ H ₄ -SO ₃ H.

This cyan toner is Met.

Copolymer of 50% styrene, 20% methyl methacrylate and 30% 2 ethylhexyl acrylate for 5 parts of this cyan toner (number average molecular weight 21250, weight average molecular weight 523
60) weight average particle diameter 45μ, 35μ or less 4.2%, 35-40μ,
A Cu-Zn-Fe based ferrite carrier having a particle size distribution of 9.5% and 34μ or more and 0.2% was mixed with 0.5% coated carrier to make a total amount of 100 parts to prepare a two-component developer.

At this time, A _L = 33 μc / g, A _H = −18 μc / g, A _L / A _H = 1.83, B _L = + 220
μc / g, B _H = + 50 μc / g, B _L / B _H = 4.4 (B _L / B _H ) / (A _L / A _H ) = 2.40.

An image obtained by setting the development contrast to 270V with a commercially available plain paper color copier (made by Color Laser Copier 500 Canon) using this two-component developer, and displaying at 23 ° C / 65 ° C. The density was as high as 1.52, and it was clear without any fog. After that, 10,000 more copies were made, but the decrease in density during that period was as small as 0.05, and fog and sharpness similar to those at the initial stage were obtained. Under low temperature and low humidity (20 ℃ / 1
0% RH), set the development contrast to 330V,
When images were printed, the image density was high at 1.48, suggesting that the present invention was effective in controlling the charge amount under low humidity.

Also, the development contrast is 250 (30 ℃ / 80%) under high temperature and high humidity.
The image density was set to V and the image density was 1.55, and a very stable and good image was obtained.

Furthermore, no abnormalities were observed in the initial images after being left in each environment of 23 ° C / 60% RH, 20 ° C / 10%, 30 ° C / 80% for 1 month.

Example 2 Acrylic resin particles used in Example 1 as an external additive
Image formation was carried out in the same manner as in Example 1 except that 0.5 part, and 0.5 part of silica fine powder treated with hexamethyldisilazane (BET specific surface area 230 m ^{2 /} g) were used. 1.35 to 1.50 1.35 to 1.50 at 23 ° C / 65% 1.45 to 1.55 at 30 ° C / 80% to 1.50 to 1.60, which was slightly lower than the environmental characteristics of Example 1, but good results were obtained.

Example 3 The content of methyl methacrylate was reduced as an external additive, the specific electric resistance was 2 × 10 ⁹ Ωcm, the number average molecular weight was 68,000, and the particle size was 6
A cyan toner was prepared in the same manner as in Example 1 except that 0.8 parts of 5 mμ acrylic resin particles were used.

At this time, B _L = + 250 μc / g, B _H = + 100 μc / g, and B _L / B _H = 2.5 (B _L / B _H ) / (A _L / A _H ) = 1.37.

When an image was formed using this cyan toner in the same manner as in Example 1, it was 1.55 to 1.70 at 30 ° C./80%, which was slightly higher than that in Example 1, but good results were obtained.

Comparative Example 1 When image formation was performed in the same manner as in Example 1 except that acrylic particles were not used, fog occurred at 20 ° C./10% and the image density also decreased.

Comparative Example 2 The procedure of Example 2 was repeated except that the acrylic particles were not used, and the temperature was 20 ° C./10% under 1.15 to 1.30 23 ° C./65% under 1.40 to 1.55 30 ° C./80% The environmental characteristics deteriorated from 1.50 to 1.60 below.

Comparative Example 3 As an external additive, the specific electric resistance is 3 × 10 ¹⁵ Ωcm and the particle size is 60 m.
The same procedure as in Example 1 was carried out except that 0.8 part of the acrylic resin particles of μ was used, and fog was generated in the background part at 20 ° C./10% or less.

〔The invention's effect〕

In the present invention, the two-component developer has a color toner and a carrier having at least non-magnetic colorant-containing resin particles and an external additive, and the external additive has a particle size of 20 to 200 mμ and a specific electric charge. Resistance 10 ⁶ ~ 10 ¹⁴
The color toner contains organic resin particles having an Ωcm and having a polarity opposite to that of the non-magnetic colorant-containing resin particles when triboelectrically charged with the carrier.
˜10 μm, containing 15 to 40% by number of non-magnetic colorant-containing resin particles having a particle size of 5 μm or less, 12.7 to 16.0 μ
The resin particles containing the non-magnetic colorant having a particle diameter of m are 0.1 to 5.0.
Since the non-magnetic colorant-containing resin particles having a particle size of 16 μm or more contained by volume% have a particle size distribution of 1.0 volume% or less, the toner is not sufficiently charged at the beginning of charging, and the rubbing At the beginning, the toner is strongly attracted to the carrier to be charged, and while the rise of the toner charge is promoted, once it rises, it is strongly attracted to the toner, and the function of neutralizing the excessive charge of the toner works. So
Even if the toner is a toner having a small particle size having a specific particle size distribution, the toner can maintain the rising charge and the saturated charge amount level in a good and stable manner in various environments. By virtue of having a particle size distribution, it is possible to faithfully reproduce the latent image formed on the photoconductor, and it is also excellent in the reproducibility of minute dot latent images such as halftone dots and digital images, especially in highlight areas. An image having excellent gradation and resolution is obtained. Furthermore, even when copying or printing out is continued, high image quality is maintained, and even in the case of a high density image, good development can be performed with a toner consumption amount smaller than that of the conventional non-magnetic toner. And the miniaturization of the main body of the copying machine or printer.

Furthermore, the above-mentioned carrier is 0 with respect to the weight of the carrier core material.
Coated with 05-10 wt% resin, weight average particle size 25-65μ
In the case of m, the present invention relates to a two-component developer, which is durable because the carrier does not adhere to the drum. Since the toner is well separated from the carrier, a more stable image can be obtained in various environments.

Furthermore, the above-mentioned carrier core material contains 98% or more of Cu-Zn-Fe.
When the ferrite has a composition of (metal composition ratio (5 to 20): (5 to 20): (30 to 80)), surface smoothness is easy, charge imparting ability is stable, and coat is stable. In addition to being able to improve the life of the carrier.

Furthermore, the frictional electrification amount between the carrier and the non-magnetic colorant-containing resin particles is A _L at 15 ° C./10% RH, and A _H at 30 ° C./80% RH. When the charge amount is B _L under 15 ° C / 10% RH and _BH under 30 ° C / 80% RH, the following conditions are 1.1 ≦ ｜ A _L / A _H | ≦ 3.0 1.2 ≦ ｜ B _L / B _H If ≦≦ 8.0 1.0 ≦ | (B _L / B _H ) / (A _L / A _H ) | ≦ 3.0, excessive charging of the toner is more positively prevented, and even in various environments. A stable image can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an apparatus for measuring the triboelectric charge amount of toner in triboelectric charge amount measurement. 1 ... Aspirator, 2 ... Measuring container, 3 ... Conductive screen, 4 ... Lid, 5 ... Vacuum gauge, 6 ... Air flow control valve, 7
...... Suction port, 8 ... Condenser, 9 ... Electrometer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03G 9/10 9/107 9/113 G03G 9/08 361 9/10 351 321 (56) References JP-A-2-877 (JP, A) JP-A-2-879 (JP, A) JP-A-1-281457 (JP, A) JP-A-1-237560 (JP, A) JP-A-1-156764 (JP, A) JP-A-64-81966 (JP, A)

Claims (4)

[Claims] 1. A color toner having at least non-magnetic colorant-containing resin particles and an external additive, and a two-component developer having a carrier, wherein the external additive has a particle size of 20 to 200 mμ and a specific electric resistance of 10 ⁶ The color toner has a volume average particle size of 6 to 10 ¹⁴ Ωcm and has a volume average particle size of 6 to 10 when it is triboelectrically charged with the carrier. Non-magnetic colorant-containing resin particles having a particle size of 10 μm and 5 μm or less are contained in an amount of 15 to 40% by number, and non-magnetic colorant-containing resin particles having a particle size of 12.7 to 16.0 μm are included in an amount of 0.1 to 5.0% by volume. And a non-magnetic colorant-containing resin particle having a particle size of 16 μm or more having a particle size distribution of 1.0 vol% or less. 2. The carrier is based on the weight of the carrier core material.
Coated with 0.05-10 wt% resin, weight average particle size 25-65
The two-component developer according to claim 1, having a thickness of μm. 3. The carrier core material is made of 98% or more Cu-Zn-Fe.
The two-component developer according to claim (2), which is a ferrite having a composition of (metal composition ratio (5 to 20) :( 5 to 20) :( 30 to 80)). 4. The triboelectrification amount of the carrier and the non-magnetic colorant-containing resin particles is A _L at 15 ° C./10% RH, and A _H at 30 ° C./80% RH of the carrier and the organic resin particles. When the triboelectric charge amount is B _L under 15 ° C / 10% RH and _BH under 30 ° C / 80% RH, the following conditions 1.1 ≦ ｜ A _L / A _H ｜ ≦ 3.0 1.2 ≦ ｜ B _L / B The two-component developer according to claim 1, wherein _{H 2} | ≦ 8.0 1.0 ≦ | (B _L / B _H ) / (A _L / A _H ) | ≦ 3.0 is satisfied.