JP2704775B2 - Color toner - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry electrophotographic toner for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing, and the like.

2. Description of the Related Art It is well known that an image is formed on a surface of a photoconductive material by electrostatic means and developed.

That is, U.S. Pat.No. 2,297,691 and JP-B-42-23910
A number of methods are known, such as Japanese Patent Publication No. JP-B-43-24748 and Japanese Patent Publication No. 43-24748, but generally, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means. By attaching an extremely finely pulverized detection material called toner on the latent image, a toner image corresponding to an electrostatic latent image is formed.

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

A developing method for visualizing an electric latent image using toner is as follows.
For example, the powder cloud method described in U.S. Pat.No. 2,221,776, the cascade development method described in U.S. Pat. A method using a conductive magnetic toner described in Japanese Patent No. 3,909,258 is known.

As a toner applied to these developing methods, a toner obtained by mixing and dispersing a colorant in a thermoplastic resin and then pulverizing the same is generally used. As the thermoplastic resin, a polystyrene resin is the most common, but a polyester resin, an epoxy resin, an acrylic resin, a urethane resin, or the like is also used. As a coloring agent, carbon black is most widely used, and in the case of a magnetic toner, iron oxide black magnetic powder is often used. 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 imaging member, such as paper,
It is permanently fixed on the support by pressure or the like. Conventionally, this fixing step has often been performed by heat.

When a step of transferring a toner image is provided, a step for removing residual toner on the photoconductor is usually provided.

2. Description of the Related Art In recent years, the development from monocolor copying to full-color copying has been rapidly progressing in copying machines and the like, and the study and commercialization of two-color copying machines and full-color copying machines have been greatly increased. For example, “Journal of the Society of Electrophotography,” Vol 22, No. 1 (198
3) and reports on color reproducibility and gradation reproducibility as described in the Journal of the Electrophotographic Society, Vol 25, No. 1, P52 (1986).

However, those who are not immediately compared with the real thing such as televisions, photographs and color prints, and for those who see color images processed more beautifully than the real ones, full color electrophotographic images currently in practical use are not necessarily It is not satisfactory.

Color image formation by full-color electrophotography generally reproduces all colors using three color toners of three primary colors, yellow, magenta, and cyan.

The method involves first forming an electrostatic latent image on the photoconductive layer through a color separation light transmission filter having a complementary color relationship with the color of the toner, and then developing and transferring the toner from the original to the support. Hold. This process is sequentially performed a plurality of times, and while the registration is being performed, the toner is overlaid on the same support, and the final full-color image is obtained by one-time fixing.

Generally, in the case of a so-called two-component system in which a developer is composed of a toner and a carrier, the developer charges the toner to a required charge amount and charge polarity by friction with the carrier, and uses electrostatic attraction to make the toner static. In order to develop an electrophotographic image, and in order to obtain a good visible image, it is necessary that the toner has good triboelectric charging properties mainly determined by the relationship with the carrier.

To solve the above-mentioned problems today, search for carrier core agents and carrier coating agents and optimize the amount of coating, or study charge control agents and fluidity-imparting agents to be added to toner, and further improve the base binder Many studies have been made to achieve excellent triboelectricity in all materials constituting the developer.

For example, as a technique of adding a charge auxiliary agent such as chargeable fine particles to a toner, Japanese Patent Publication No.
No. -64352 discloses a resin fine powder having a polarity opposite to that of the toner,
Japanese Patent Application Laid-Open No. 61-160760 proposes a technique of adding a fluorine-containing compound to a developer to obtain a stable triboelectric charging property, and many charging aids are still being developed today. .

Further, various techniques have been devised as a method for adding the charging auxiliary as described above. For example, a method of attaching the toner particles to the surface of the toner particles by electrostatic force or Van der Waals force between the toner particles and the charge auxiliary agent is generally used, and a stirrer, a mixer or the like is used. However, in this method, it is not easy to uniformly disperse the additive on the surface of the toner particles, and the presence of the additive which is not attached to the toner particles but aggregates together, that is, in a so-called free state is considered. It is difficult to avoid. In such a case, the performance as a developer is affected. For example, the amount of triboelectricity of the toner becomes unstable, so that the image density is not constant and the image has a lot of fog.

Or, when continuous copying is performed, the content of the charging auxiliary changes, and the image quality at the initial stage cannot be maintained.

As another addition method, there is a method in which a charging auxiliary is added in advance together with a binder resin and a colorant during the production of the toner. However, it is not easy to make the charge control agent uniform, and it is substantially in the vicinity of the toner particle surface that contributes to the chargeability, and the charge auxiliary agent and the charge control agent present inside the toner particles are charged. Therefore, it is not easy to control the amount of the charge auxiliary agent added and the amount of dispersion on the surface. Also, in the toner obtained by such a method, the amount of triboelectric charge of the toner is unstable, and it is not easy to obtain a toner satisfying the developer characteristics as described above. The fact is that satisfactory quality has not been obtained.

Furthermore, in recent years, the demand for higher definition and higher image quality of copying machines has been increasing in the market, and in this technical field, attempts have 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 tends to increase, and the amount of charge of the toner tends to increase. In addition, since the charged amount of the toner is large, the adhesion between the toners is strong, the fluidity is reduced, and problems occur in the stability of toner supply and in the application of tribo to the supplied toner.

In the case of a color toner, since it does not contain a magnetic substance or a conductive substance such as carbon black, there is no portion that leaks charge, and the amount of charged electricity generally tends to be large. This tendency is more remarkable especially when a polyester system having a high chargeability is used.

In particular, in the case of a color toner, the following characteristics are strongly desired.

(1) In order that the fixed toner does not diffusely reflect light and hinder color reproduction, the toner needs to be in a state of almost complete melting such that the shape of the toner particles cannot be determined.

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

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

From such a viewpoint, many binder resins have been studied, but a toner satisfying all of the above characteristics has not yet been developed. Today, polyester resins are widely used as binder resins for color in the technical field. However, toners made of polyester resins are generally easily affected by temperature and humidity, and have an excessive charge amount under low humidity and high humidity. Under such circumstances, there arises a problem such as insufficient charge amount, and there is an urgent need to develop a color toner having a stable charge amount even in a wide range of environments.

For the purpose of improving environmental stability,
As disclosed in JP-A-40407 and JP-A-56-65147, environmental stability has been attempted by controlling the amount of residual carboxyl groups, that is, by adjusting the acid value. However, these proposals, although having a relieving effect on charge-up under low humidity, are still insufficient for long-term stability.

In particular, in color toners that do not contain carbon black or magnetic materials, measures to increase the charge are indispensable.
It is necessary to improve not only the binder resin but also all the constituent materials including additives.

[Problems to be Solved by the Invention] The object of the present invention is to be less affected by the environment such as temperature and humidity.
It is an object of the present invention to provide a color toner which has always stable triboelectrification and clear image characteristics without fog and has excellent durability stability.

Another object of the present invention is to provide a color toner having good fluidity.

[Means and Actions for Solving the Problems] The present invention relates to an insulating nonmagnetic color toner having at least nonmagnetic colorant-containing polyester resin particles and a flow improver, wherein the colorant-containing polyester The resin particles have a volume average diameter of 4 to 10 μm, and the constituent components are mainly composed of a diol component and a dicarboxylic acid component, and at least a part of —COOH is substituted by a functional group containing N to improve the fluidity. When at least one of the agents is frictionally charged with a carrier having a weight average particle diameter of 25 to 65 μm, which is a carrier core material coated with an electrically insulating resin of 0.05 to 10% by weight based on the weight of the carrier core material, A color toner having an absolute value of 20 μc / g or less.

The present inventor has conducted detailed studies on polyester resins, and as a result, instead of simply controlling the acid value,
Polyester remaining-at least part of the COOH is an amine,
It has been found that by replacing with a functional group containing N such as azine and pyridinium salt, charging stability can be achieved for a long time in a wide range of environments.

That is, by replacing at least a part of -COOH with a functional group containing N, the toner becomes less likely to absorb moisture under high humidity. As a result, a decrease in charging under high humidity can be suppressed to some extent.

In general, the negative charge of a polyester resin tends to be excessive under low humidity. However, by treating with a modifier containing N, the positive charge ability of the modifier is appropriately reduced. The charge is neutralized, which is very effective in suppressing charge-up.

Furthermore, in order to make the present invention more effective, the sum of the acid value and the hydroxyl value is 3 to 20 mgKOH / g, preferably 4 to 1 mgKOH / g.
A toner having sufficient environmental stability of charging to 5 mgKOH / g and a color toner having good dispersibility of the colorant are achieved,
desirable.

Replacing at least a part of the -COOH with a functional group containing N is disclosed in JP-A-61-14644 and the like, but these are intended only for a positively chargeable toner. This is a completely different invention from the negatively chargeable color toner of the invention.

JP-A-62-195676, JP-A-62-195678, JP-A-62-195676
According to JP-A-195680, JP-A-62-195681 and JP-A-62-195682, it is stated that if the amount of terminal groups, especially the amount of carboxyl groups, is excessively reduced, the charge amount of the polyester resin is reduced. The inventor has found that the amount of charge takes a sufficient value by containing a suitable charge control agent which is preferable in forming a toner. Further, according to the above-mentioned publication, it is described that the ratio between the hydroxyl value and the acid value is adjusted to 1.2 or more for the purpose of improving the fluidity and lowering the minimum fixing temperature, but the present inventor uses the additives described below. As a result, it has been found that a stable fixing performance can be obtained because a proper fluidity and a proper filling state of the toner layer on the transfer material can be achieved.

In the present invention, in order to replace at least a part of -COOH with a functional group containing N, a functional group NH reactive with -COOH is used.
_A modifier having ₂ , NHR, NR ₂ or the like may be treated after the polyester polymerization reaction.

As the diol component of the polyester resin used in the present invention, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3
-Butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, pentaerythritol diallyl ether, trimethylene glycol, 2-ethyl-1,3-hexane A diol, hydrogenated bisphenol A, or a bisphenol derivative represented by the following formula; (Wherein 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 to 2)
It is 10. ) And the like.

Further, as the dicarboxylic acid component, fumaric acid, maleic acid, citraconic acid, unsaturated dicarboxylic acids such as itaconic acid, or acid anhydrides thereof, succinic acid, adipic acid,
Examples thereof include dicarboxylic acids such as sebacic acid and azelaic acid, and anhydrides thereof, and aromatic dicarboxylic acids such as phthalic acid and terephthalic acid.

As the diol component used in the present invention, 40 to 60 mol
%, Preferably 45 to 55 mol%, and the dicarboxylic acid component is desirably 60 to 40 mol%, preferably 55 to 45 mol%.

Examples of the N-containing modifier used in the present invention include diethanolamine, dimethylaminoethanol, triethanolamine, polyalkyleneamine, diethylenetriamine, and triethylenetetramine.

 The method for producing the polyester resin is as follows.

Under an inert gas atmosphere (often in the presence of nitrogen gas)
The reaction is carried out at normal pressure to reduced pressure (0~-760mmH ₂ O). With stirring, the temperature is raised to 60 to 270 ° C, preferably to 80 to 220 ° C,
Incubate for 30 hours. Water or alcohols produced by the condensation polymerization are continuously discharged out of the system together with the inert gas while supplying the inert gas into the system, so that the condensation polymerization proceeds. For example, an acid and an alcohol are charged into a reaction vessel equipped with a stirrer, a condenser, a thermometer, and an inert gas introduction pipe. Next, gas replacement is performed by introducing an inert gas. After the completion of the gas replacement, the inert gas is kept flowing, the reaction temperature is raised to a predetermined temperature, and the condensation polymerization reaction is performed with stirring for 10 to 30 hours. Water or alcohol produced by the condensation polymerization reaction is condensed and recovered by a condenser outside the system. At the end of the reaction, a modifier is added to treat the -COOH group.

After the completion of the reaction, the generated water or the residual modifier in the case where the added modifier is excessive is evaporated under reduced pressure and condensed by a condenser outside the system and collected. Thereafter, the temperature is lowered to room temperature to obtain a polyester resin.

Here, the polyester resin in the present invention preferably has a total of the acid value and the hydroxyl value of 3 to 20 mgKOH / g due to its properties, and if it exceeds 20 mgKOH / g, the number of carboxyl groups or hydroxyl groups increases, and Environmental dependency is increased, and restrictions on usable coloring agents, external additives, and the like are increased.

On the other hand, if it is less than 3 mgKOH / g, the dispersion of the colorant dispersed in the resin tends to be non-uniform, which may cause adverse effects such as toner scattering and fog.

The method for measuring the acid value and the hydroxyl value used in the present invention will be described below.

For the measurement of the acid value, 2 to 10 g of a sample are weighed in a 200 to 300 ml Erlenmeyer flask, and about 50 ml of a mixed solvent of methanol: toluene = 30: 70 is added to dissolve the resin. If the solubility is poor, a small amount of acetone may be added. Using a mixed indicator of 0.1% bromthymol blue and phenol red, titrate with a previously standardized N / 10 potassium hydroxide-alcohol solution, and calculate the acid value from the consumption of the alcohol potassium solution by the following formula (I). Ask.

Acid value = KOH (number of ml) × N × 56.1 / sample weight (I) (where N is a factor of N / 10 KOH) In addition, the hydroxyl value is measured by measuring the sample with an excess acetylating agent such as acetic anhydride. After acetylation by heating and measuring the saponification value of the acetylated product produced, the acetylation is calculated according to the following formula (II).

(However, A represents the saponification value after acetylation, and B represents the saponification value before acetylation.) The toner according to the present invention may contain a charge control agent in order to stabilize the charge characteristics. . At that time, a colorless or light-colored 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 an organic metal complex such as a metal complex of an alkyl-substituted salicylic acid (for example, a chromium complex or a zinc complex of di-tert-butylsalicylic acid). When the negative charge control agent is blended in the toner, 0.1 to 10 parts by weight, preferably 0.5 to 100 parts by weight of the binder resin.
It is better to add up to 8 parts by weight.

When preparing a two-component developer by mixing with the toner according to the present invention, the mixing ratio is as a toner concentration in the developer,
Good results are usually obtained at 2.0 to 10% by weight, preferably 3 to 9% by weight. If the toner concentration is less than 2.0% by weight, the image density is low and it becomes impractical. If the toner concentration exceeds 10% by weight, fog and scattering in the machine are increased, and the useful life of the developer is shortened.

As the colorant used in the present invention, known dyes and pigments,
For example, phthalocyanine blue, induslen blue, peacock blue, permanent red, lake red,
Rhodamine lake, Hansa yellow, permanent yellow, benzine yellow and the like can be widely used.
The content thereof is 12 parts by weight or less, preferably 0.5 to 9 parts by weight with respect to 100 parts by weight of the binder resin so as to be sensitively reflected on the permeability of the OHP film.

The flow improver used in the present invention has an absolute value of a charge amount of 20 μc / g when frictionally charged with the carrier used in the present invention.
In the following, it is necessary to contain at least one preferably 10 μc / g or less.

More preferably, as a flow improver, the absolute value of the triboelectric charge amount with the carrier is 20 μc / g or less, the specific surface area by the BET method is 30 to 200 m ² / g, and the triboelectric charge amount with the carrier. The negatively chargeable hydrophobic inorganic oxide having an absolute value of 50 μc / g or more and a specific surface area of 80 to 300 m ² / g by a BET method is used in an amount of 0.3 to ² % by weight based on the colorant-containing resin particles.

As in the present invention, even if the chargeability as a binder resin is stabilized, the use of a silicate fine powder or the like generally used as a flow improver alone can improve the flowability, but the charging characteristics. In particular, charging tends to be excessive particularly under low humidity, and as a result, environmental stability of the toner is impaired. This tendency becomes more remarkable as the particle size of the toner is reduced and the amount of the flow improver used is increased.

However, as in the present invention, by including at least one type of flow improver having a weak chargeability as a flow improver, it was possible to achieve both charging characteristics and flowability.

Examples of the flow improver include, but are not necessarily limited to, the following. For example, Al ₂ O ₃ , Ti
Metal oxides such as O ₂ , GeO ₂ , ZrO ₂ , Sc ₂ O ₃ , HfO ₂ , SiC, TiC, W
_There are carbides such as ₂ C and nitrides such as Si ₃ N ₄ and Ge ₃ N ₄ , among which Al ₂ O ₃ , TiO ₂ , Sc ₂ O ₃ , ZrO ₂ , GeO ₂ , HfO ₂ are colorless When used for a color toner in that it is white, it is preferable because it does not adversely affect the color. Also especially Al ₂ O
₃ , TiO ₂ and ZrO ₂ are more preferable because they can be easily produced with a suitable particle size by a gas phase method. Further, a hydrophobic treatment may be performed. The finer the particle size of the particles to be added, the better.In the present invention, the specific surface area measured by the BET method is 30 m ² /
A flow-providing agent in the range of g to 200 m ² / g is used. More preferably, the particle size is 50 m ² / g or more, and the smaller the particle size, the better the flow characteristics of the toner.

In particular, as the above-mentioned hydrophobic inorganic oxide, it is more preferable to use a treated silica fine powder obtained by subjecting a silica fine powder produced by gas phase oxidation of a silicon halide compound to a hydrophobic treatment. It is particularly preferable that the treated silica fine powder is obtained by treating the silica fine powder such that the degree of hydrophobicity measured by a methanol titration test shows a value in the range of 30 to 80.

Hydrophobization is applied by reacting with silica fine powder or chemically treating it with an organic silicon compound that physically adsorbs.

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

Examples of such organosilicon compounds are hexamethyldisilazane, trimethylsilane, trimethylchlorosilane,
Trimethylethoxysilane, dimethyldichlorosilane,
Methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α
-Chloroethyltrichlorosilane, ρ-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane,
Triorganosilyl mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane,
Dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and 2 to 12 siloxane units per molecule with terminal positions For example, dimethylpolysiloxane containing a hydroxyl group bonded to one Si unit may be used for each unit. These are used in one kind or in a mixture of two or more kinds.

Commercial products include Taranox-500 (Talco),
Aerosil R-972 (Nippon Aerosil) and the like. The addition amount is 0.3 to 2% by weight based on the resin particles.

Although the amount of addition is related to the particle size distribution of the resin particles described below, if it is less than 0.3% by weight, it is difficult to achieve appropriate fluidity, and if it is more than 2% by weight, adverse effects such as toner scattering and fogging are likely to occur.

Additives may be added to the toner of the present invention as needed as long as the properties of the toner are not impaired. Examples of such additives include Teflon, zinc stearate, and lubricants such as polyvinylidene fluoride. Alternatively, there are fixing aids (eg, low molecular weight polyethylene, low molecular weight polypropylene, etc.).

In the production of the toner of the present invention, after the constituent materials are well wrought by a hot kneader such as a hot roll, a kneader, an extruder, and then mechanically pulverized and classified, or a method of obtaining a magnetic material in a binder resin solution. A method in which a material such as a powder is dispersed and then spray-dried, or a method in which a predetermined material is mixed with a monomer to constitute a binder resin and then the emulsion suspension is polymerized to obtain a toner. Each method such as a method for producing a polymerized toner can be applied.

In the color toner of the present invention, the volume average particle diameter of the toner is 6 to 10 μm, the toner particles having a particle diameter of 5 μm or less are 15 to 40% by number, 12.7 to 16.0 μm are 0.1 to 5.0% by volume, and 16 μm or more. 1.05% by volume or less, 6.35 to 10.1
μm toner particles have the following formula The effect is more pronounced when having a particle size distribution that satisfies

The toner having the above particle size distribution can faithfully reproduce a latent image formed on a photoreceptor, and is excellent in reproducing a minute dot latent image such as a halftone dot and a digital image. An image excellent in gradation and resolution of the part 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 smaller amount of oner consumption than the conventional non-magnetic toner. It also has advantages in terms of performance and miniaturization of the copier or printer body.

The reason why such an effect is obtained in the color toner of the present invention is not necessarily clear, but is presumed as follows.

Conventionally, in a color toner, toner particles having a particle size of 5 μm or less are difficult to control the charge amount, impair the fluidity of the toner, and scatter the toner to contaminate the machine. As
It was thought that aggressive reduction was necessary.

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

For example, using a two-component developer having a non-magnetic toner and a carrier having a particle size distribution ranging from 0.5 μm to 30 μm, the surface potential on the photoreceptor is changed, and a large development potential contrast in which many toner particles are easily developed. From halftone to halftones, and then to latent images of small dots where only a few toner particles are developed. Was collected and the toner particle size distribution was measured.
It was found that there were many toner particles having a particle size of m or less, especially about 5 μm on the latent image of fine dots. That is,
When the toner particles having a particle size of about 5 μm are smoothly supplied to the development of the latent image on the photoreceptor, the toner is faithful to the latent image, and an image with excellent reproducibility can be obtained without protruding from the latent image. It is.

Further, the toner particles of 12.7 μm to 16.0 μm are related to the necessity of the existence of toner particles having a particle size of about 5 μm.
Non-magnetic toner particles having a particle size of m or less certainly have the ability to faithfully reproduce the latent image of fine dots, but themselves have considerably high cohesiveness, which may impair the fluidity of the toner.

The present inventors have proposed the above-mentioned 2 for the purpose of improving fluidity.
By adding more than one kind of inorganic oxide, further improvement in fluidity was attempted.However, only means for adding an inorganic additive are not enough to satisfy all conditions such as image density, toner scattering, and fog. Was confirmed to be narrow. Therefore, the present inventors further studied the particle size distribution of the toner, and found that the toner particles having a particle size of 5 μm or less
It has been found that fluidity is further improved and high image quality can be achieved by containing 0.1% to 5.0% by volume of toner particles of 12.7 to 16.0 μm after containing 40% by number. That is,
It is considered that the toner particles in the range of 12.7 to 16.0 μm have a moderately controlled fluidity with respect to the toner particles of 5 μm or less, and as a result, high-resolution images are obtained even when copying or printing is continued. This provides a sharp image with excellent characteristics and gradation.

Further, for the toner particles of 0.35 to 10.1 μm, between the volume% (V), the number% (N) and the volume average particle size (v), It is further desirable that the color toner of the present invention satisfies the following relationship.

The present inventors have studied the state of the particle size distribution and the development characteristics and found that there is a state of existence of the particle size distribution most suitable for achieving the object as shown by the above formula.

In other words, when the particle size distribution is adjusted by general air classification, the above value is large, which means that toner particles of about 5 μm that faithfully reproduce a minute dot latent image increase, and that the above value is small. It is understood that this indicates that 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, good toner fluidity and faithful latent image reproducibility are achieved.

For toner particles having a particle size of 16 μm or more, 1.0
It is preferable that the content be as small as possible by volume.

The configuration of the present invention will be described in more detail. 5μ
The number of toner particles having a particle size of m or less is preferably 15 to 40% by number of the total number of particles, and more preferably 20 to 35% by number.
When the number of toner particles having a particle size of 5 μm or less is 15% by number or less, the amount of non-magnetic toner particles effective for high image quality is small.
As the toner is used by continuing to copy or print out, the effective toner particle component decreases,
The balance of the particle size distribution of the toner deteriorates, and the image quality gradually decreases. On the other hand, if the content is more than 40% by number, toner particles are likely to aggregate with each other, resulting in a toner mass larger than the original particle size, resulting in rough image quality, reduced resolution, or an edge portion of a latent image. The density difference between the image and the inside becomes large, and the image tends to be slightly hollow.

Further, the particle size in the range of 12.7 to 16.0 μm is preferably 0.1 to 5.0% by volume, and more preferably 0.2 to 3.0% by volume. Five.
If the content is more than 0% by volume, the image quality is deteriorated, and the development is performed more than necessary, that is, the toner is excessively applied, which causes an increase in toner consumption. On the other hand, if it is less than 0.1% by volume,
The image density decreases due to the decrease in fluidity.

Further, the content of toner particles having a particle diameter of 16 μm or more is preferably 1.0% by volume or less, more preferably 0.6% by volume or less. Due to the existence of coarse toner particles of 16 μm or more protruding on the thin layer surface of the toner particles developed on the photoconductor, the delicate adhesion between the photoconductor and the transfer paper through the toner layer is irregular. As a matter of fact, it is likely to cause a change in the transfer condition and to cause a transfer failure image. Further, the volume average diameter of the toner is 6 to 10 μm, preferably 7 to 9 μm, and this value cannot be considered separately from the above-mentioned respective constituent elements.
When the volume average particle diameter is less than 6 μm, in applications having a high image area ratio such as a graphic image, there is a problem that the amount of applied toner on the transfer paper is small and the image density is low.
This is considered to be due to the same reason as described above for lowering the density inside the edge portion of the latent image.
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 particle size distribution of the toner can be measured by various methods, but in the present invention, the measurement was performed using a Coulter counter.

That is, as a measuring device, Coulter Counter TA-II
Using an interface (manufactured by Coulter) and an interface (manufactured by Nikkaki) that outputs the number distribution and volume distribution and a CX-1 personal computer (manufactured by Canon), the electrolyte is 1
Prepare a 1% aqueous NaCl solution using graded sodium chloride.
As a measurement method, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the aqueous electrolytic solution, and 2 to 20 mg of a measurement sample is further added.
The electrolyte solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and the Coulter Counter TA-II was used, and a 100-μm aperture was used as an aperture. The particle size distribution was measured and the values according to the invention were determined therefrom.

As for the carrier used as a mixture with the color toner of the present invention, an electrically insulating resin is used as a coating resin for the carrier core material, and 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 an acrylic acid (or an ester thereof) monomer and a methacrylic acid (or an ester thereof) monomer in order to improve the adhesion to the carrier core material surface. Must be contained. Especially as a toner material,
When a polyester resin particle having a high negative chargeability is used, it is preferable to further use a copolymer with a styrene monomer for the purpose of stabilizing the charge, and the copolymerization weight ratio of the styrene monomer is 5 to 70% by weight. % Is preferable.

The average molecular weight of the copolymer, the number average molecular weight is 10,000 in consideration of the uniformity of the coating of the carrier core material surface, the coating strength.
~ 35,000, preferably 17,000-24,000, weight average molecular weight is 2
It is preferably between 5,000 and 100,000, preferably between 49,000 and 55,000.

As the monomer for the coating resin of the carrier core material that can be used in the present invention, examples of the styrene-based monomer include a styrene monomer, a chlorostyrene monomer, an α-methylstyrene monomer, and a styrene-chlorostyrene monomer. For example, acrylate monomers (methyl acrylate monomer, ethyl acrylate monomer, butyl acrylate monomer,
Octyl acrylate monomer, phenyl acrylate monomer, 2-ethylhexyl acrylate monomer) and the like, and methacrylate ester monomers (methyl methacrylate monomer, ethyl methacrylate monomer, butyl methacrylate monomer, phenyl methacrylate monomer).

As the magnetic particles used in the present invention, for example, metals such as iron, nickel, copper, zinc, cobalt, manganese, chromium, rare earth and the like, and their alloys or oxides, whose surface is oxidized or not oxidized, can be used. There is no particular limitation on the manufacturing method.

 Hereinafter, the measurement method according to the present invention will be described.

Measurement of triboelectric charge: The measurement method will be described in detail with reference to the drawings.

FIG. 1 is an explanatory view of an apparatus for measuring a triboelectric charge amount of a toner. First, in a metal measuring container 2 having a 500-mesh screen 3 at the bottom, a mixture of a toner and a carrier having a weight ratio of 1:19 to be measured for a triboelectric charge amount or 1:49 in the case of an external additive is used. Is placed in a polyethylene bottle having a capacity of 50 to 100 ml and shaken by hand for about 10 to 40 seconds. Then, about 0.5 to 1.5 g of the mixture (developer) is added, and the metal lid 4 is closed.
At this time, the weight of the entire measurement container 2 is weighed and defined as W ₁ (g). Next, in the suction device 1 (at least the portion in contact with the measurement container 2 is at least an insulator), the suction is performed through the suction port 7 and the air volume control valve 6 is adjusted to adjust the pressure of the vacuum gauge 5 to 250 mmAq. In this state, suction is sufficiently performed, preferably for 2 minutes, to remove the toner by suction. The potential of the electrometer 9 at this time is set to V (volt). Here, reference numeral 8 denotes a capacitor, whose capacity is C (μF). In addition, weigh the entire measurement container after suction and weigh W ₂ (g).
And The triboelectric charge (μc / g) of this toner is calculated as in the following equation.

(However, the measurement conditions are 23 ° C. and 60% RH.) The carrier used for the measurement is a styrene-based resin-coated ferrite carrier having a 250-mesh pass, 350-mesh-on carrier particles of 70 to 90% by weight.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples (Examples of producing a polyester resin and Examples of a toner using the resin).

Resin production example 1 The above compounds were mixed at a molar ratio of 1: 1 and placed in a two-volume, four-necked round-bottomed flask equipped with a thermometer, a Teflon-coated stirrer, a glass nitrogen inlet tube, a condenser, and a pressure reducing device. After the by introduction of nitrogen gas reactor than the glass inlet tube an inert atmosphere, by adjusting the opening of the pressure reducing control valve and a nitrogen gas inlet valve, maintaining the system inside -750mmH ₂ O. Thereafter, the reactor was placed in a mantle heater, and a condensation reaction was performed at 170 ° C. for 20 hours. The pressure at this time was also kept at -750mmH ₂ O.

 This is designated as resin A.

 Thereafter, acetic acid was added to the system to obtain resin B.

Further, diethanolamine was added to the system to obtain a modified polyester resin C.

Separately, triethanolamine was added instead of diethanolamine to obtain a modified polyester resin D. Table 1 shows the acid value and the hydroxyl value of the resins A to D.

Example 1 Is sufficiently premixed with a Henschel mixer, melt-kneaded at least twice with a three-roll mill, cooled, roughly crushed to about 1 to 2 mm using a hammer mill, and then finely crushed by a fine crusher using an air jet method. did. Further, the obtained finely pulverized product was classified to select a particle size of 2 to 10 μm so as to have the particle size distribution of the present invention, thereby obtaining colorant-containing resin particles.

0.5 parts by weight of hexamethyldisilazane treated with 0.5 parts by weight of hexamethyldisilazane to 100 parts by weight of the colorant-containing resin particles triboelectric charge -55 μc / g, specific surface area of 230 m ² / g by BET method and 0.5 parts by weight of alumina fine powder friction A cyan toner was obtained by externally adding a charge amount of 1.7 μc / g and a specific surface area of 100 m ² / g by a BET method.

This cyan toner Met.

A copolymer composed of 50% styrene, 20% methyl methacrylate, and 30% 2-ethylhexyl acrylate (number average molecular weight 21,250, weight average molecular weight 52360) was added to 6 parts by weight of the cyan toner. ,
Cu with a particle size distribution of 35-40μ, 9.5%, 0.2% of 74μ or more
A carrier in which 0.5% of a -Zn-Fe-based ferrite carrier was coated was mixed to make a total amount of 100 parts by weight to prepare a developer.

Using this developer, the development contrast was adjusted to 350 V with a commercially available plain paper color copier (manufactured by Color Laser Copier 500 Canon), and the resulting image was a high density 1.52 with no fog. Not clear. Thereafter, 10,000 copies were further made, during which the density decrease was as small as 0.05, and fog and sharpness were equivalent to those at the initial stage. The image density under low temperature and low humidity (20 ° C., 10% RH) was as high as 1.45, suggesting that the present invention was effective in controlling the charge amount under low humidity.

The image density was stable at 1.55 to 1.60 even at high temperature and high humidity (30 ° C./80%).

Further, no abnormalities were observed in the images left for one month in each environment of 23 ° C./60% RH, 20 ° C./10%, and 30 ° C./80%.

Example 2 Example 1 except that resin D was used instead of resin C.
The image density was reduced by 0.05 at 15 ° C / 10%, and the image density was slightly higher at 30 ° C / 80% by 0.10 at 30 ° C / 10%. A good image was obtained.

Comparative Example 1 The procedure of Example 1 was repeated, except that the resin B was used, except that the image density was as low as 1.40 under low humidity (20 ° C./10%). It has dropped.

Comparative Example 2 When image formation was performed in the same manner as in Example 1 except that resin A was used, the image density under low humidity was 1.
35 and low image density under high humidity (30 ℃ / 80%) 1.72
Environmental stabilization had not been achieved.

Example 3 In Example 1, instead of the alumina fine powder, -10
When the same procedure as in Example 1 was carried out except that 0.7 part by weight of titanium fine powder having a specific surface area of 80 m ² / g at μc / g was used, good results were obtained.

Comparative Example 3 An image was formed in the same manner as in Example 1, except that 1.2 parts by weight of the silica fine powder and 1 part by weight of the alumina fine powder were used. Under wet conditions (30 ° C / 80%), toner scattering occurred from about 200 sheets.

Comparative Example 4 The same procedures as in Example 1 were carried out except that the alumina fine powder was not used. The initial image density was as low as 1.25 at 20 ° C./10%.
It decreased from 1.25 to 1.10.

Comparative Example 5 The alumina fine powder used in Example 1 was subjected to a hydrophobizing treatment with dimethyl silicone oil, and the charge amount with the magnetic particles was −25.
A μc / g hydrophobic alumina fine powder was obtained. An image was formed in the same manner as in Example 1 except that 0.5 part by weight of this fine powder was used. At 20 ° C./10%, fog was generated due to the durability of about 1,000 sheets, resulting in an image with a lot of roughness. Oops.

Example 4 In Example 1, instead of the phthalocyanine pigment, CI
Pigment Yellow 17 magenta toner using 3.5 parts by weight of yellow toner and 0.9 parts by weight of CI Solvent Red 49 and 1.0 parts by weight of CI Solvent Red 52, and CI
Pigment Yellow 17 (1.2 parts by weight), CI Pigment Red 5 (2.8 parts by weight), and CI Pigment Blue 15 (1.5 parts by weight) were adjusted to three color toners such that the particle size distribution was substantially the same as the cyan toner. A full-color image was obtained with a total of four color toners including the cyan toner used in Example 1. High quality and high density images were obtained even when the durability was 5,000 sheets, and toner scattering and fog under high temperature and high humidity were minimized.

[Effect of the Invention] As described above, according to the present invention, a high-quality image can be stably supplied for a long period of time even in a so-called environment.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an apparatus for measuring a triboelectric charge amount in the present invention.

Claims (3)

(57) [Claims] An insulating non-magnetic color toner having at least a non-magnetic colorant-containing polyester resin particle and a flow improver, wherein the colorant-containing polyester resin particle has a volume average diameter of 4%. Μ10 μm, and the constituent components are mainly composed of a diol component and a dicarboxylic acid component, and at least a part of —COOH is substituted by a functional group containing N. At least one of the flow improvers has a carrier core material weight. When a carrier having a weight average particle size of 25 to 65 μm coated with a carrier core material of 0.05 to 10% by weight of an electrically insulating resin is frictionally charged, the absolute value of the charge amount is 20 μc / g or less. A color toner characterized by the following. 2. The color toner has a volume average diameter of 6 to 10 μm, and 15 to 40% by number of toner particles having a particle diameter of 5 μm or less, 0.1 to 5.0 volume% of 12.7 to 16.0 μm, and 0.1 to 5.0% by volume of 16 μm or more.
1.05% by volume or less and 6.35 to 10.1 μm toner particles are represented by the following formula: 3. The color toner according to claim 1, wherein the following is satisfied. 3. A flow improver having an absolute value of a triboelectric charge amount with a carrier of 20 μc / g or less and a specific surface area of 30 to 30 μm by a BET method.
200 m ² / g hydrophilic inorganic oxide, the absolute value of the triboelectric charge amount with the carrier is 50 μc / g or more and the specific surface area by the BET method is 80 to
The color toner according to claim 1 or 2, wherein 300 m ² / g of the negatively charged hydrophobic inorganic oxide is added in an amount of 0.3 to 2% by weight based on the colorant-containing resin particles. .