JPH086286A - Color toner and developer - Google Patents

Abstract

PURPOSE:To provide a color toner excellent in flowability and transferability and capable obtaining a clear color image free from fog. CONSTITUTION:This color toner contains treated fine powder, as an additive, obtd. by treating the surface of fine powder of a compsn. consisting essentially of 85-99.5% TiO2 and 0.5-15% Ti(OR)m(OH)n with a silane-contg. org. compd. This toner has 3-7mum wt. average particle diameter and contains >40% by number of toner particles each having <=5.04mum particle diameter, 10-70% by number of toner particles each having <=4mum particle diameter, 2-20vol.% toner particles each having >=mum particle diameter and <=6vol.% toner particles each having >=10.08mum particle diameter.

Description

Detailed Description of the Invention

[0001]

The present invention relates to electrophotography, electrostatic recording,
The present invention relates to a color toner and a developer for developing an electrostatic charge image in electrostatic printing or the like.

[0002]

BACKGROUND OF THE INVENTION It is well known in the art to form an image on the surface of a photoconductive material by electrostatic means and develop with toner.

That is, US Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-43.
Although a number of methods are known, such as Japanese Patent No. 24748, a photoconductive substance is generally used to form an electric latent image on a photoconductor by various means, and then the toner is called toner on the latent image. A toner image corresponding to an electrostatic latent image is formed by adhering an extremely finely ground electrophotographic material.

Then, the toner is transferred onto the surface of the image support such as paper, if necessary, 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.

A developing method for visualizing an electric latent image by using a toner is, for example, a powder cloud method described in US Pat. No. 2,221,776 and 2,618,55.
No. 2 specification, cascade development method, No. 2,874,063 specification, magnetic brush method, and No. 3,909,258 specification, conductivity. A method using a magnetic toner is known.

As the toner applied to these developing methods, a toner obtained by mixing and dispersing a colorant in a thermoplastic resin and then pulverizing it is generally 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. Conventionally, this fixing process has been often adopted by heat.

When the method has a step of transferring a toner image, a step for removing the residual toner on the photosensitive member is usually provided.

In recent years, the development from mono-color copying to full-color copying has been rapidly progressing in copying machines and the like, and two-color copying machines and full-color copying machines have been studied and put to practical use. For example, "Electronic Photography Society" Vol
22, no. 1 (1983) and "Electronic Photography Society" Vo
l 25, No. 1, P52 (1986), there are reports of color reproducibility and gradation reproducibility.

However, it is not immediately compared to the real thing like a TV, a photograph, and a color printed matter, and for people who can see a color image which is more beautifully processed than the real thing, the full-color electrophotography currently in practical use. Images are not always pleasing.

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

In the method, first, light from the original is passed through a color separation light transmitting filter having a complementary color relationship with the color of the toner to form an electrostatic latent image on the photoconductive layer, and then the toner is subjected to development and transfer steps. Hold on a support. This step is sequentially carried out a plurality of times, the toners are superposed on the same support while matching the registration, and then the final full-color image is obtained by fixing once.

Generally, in the case of a so-called two-component developing system in which the developer is composed of toner and carrier, the developer charges the toner to a required charge amount and charge polarity by friction with the carrier and utilizes electrostatic attraction. In order to obtain a good visible image, it is necessary that the triboelectric chargeability of the toner, which is mainly determined by the relationship with the carrier, is good.

To solve the above problems, the search for carrier core agents and carrier coating agents and the optimization of the coating amount, the examination of charge control agents and fluidity imparting agents to be added to toners, and the binder serving as the base material are taken place. Many studies have been made to achieve excellent triboelectrification properties in all materials constituting a developer, including improvements in the above.

For example, Japanese Patent Publication No. 52-32256 and Japanese Unexamined Patent Publication No. 56-64352 disclose a technique of adding a charging auxiliary agent such as chargeable fine particles to a toner. JP-A-61-160760 discloses that a fluorine-containing compound is added to each developer,
A technique for obtaining a stable triboelectric charging property has been proposed, and many charging aids have been developed even today.

Furthermore, various methods have been devised as a method of adding the charging auxiliary agent as described above. For example, a method of attaching the toner particles to the surface of the toner particles by an electrostatic force between the toner particles and the charging aid, or a Van der Waals force is generally used.
Stirring, a mixer, etc. are used. However, in this method, it is not easy to uniformly disperse the additive on the surface of the toner particle, and the additive does not adhere to the toner particle and the additives become aggregates, so that there is an additive in a so-called free state. Is difficult to avoid. This tendency becomes more remarkable as the specific electric resistance of the charging aid increases and the particle size decreases. In such a case, the performance of the toner is affected. For example, the amount of triboelectricity becomes unstable, the image density is not constant, and the image becomes fogged.

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

As another addition method, there is a method in which a charging auxiliary agent is added in advance 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 substantially contributed to the charging property.
It is not near the surface of the toner particles, and the charging aid and charge control agent present inside the particles do not contribute to the charging property, so that 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. It is the actual situation that the product of satisfactory quality is not obtained by itself.

Further, in recent years, demands for high definition and high image quality of copying machines have been increasing in the market, and in this technical field, attempts have been made to achieve high image quality color by making toner particle size fine. However, as the particle size becomes smaller, the surface area per unit weight increases, and the amount of charge on 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 toner has a large charge amount, the adhesion between the toners is strong, the fluidity is lowered, and problems arise in stability of toner replenishment and imparting tribo to the replenishment toner.

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

Particularly 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, and a toner satisfying all of the above characteristics is desired. 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 having a stable charge amount even in a wide range of environments due to the problem that the charge amount is insufficient.

Conventionally, a metal oxide such as titanium oxide is used as a polishing agent in JP-A-48-47345, and as a fluidizing agent in JP-A-52-19535 and JP-A-56-128956. ing. Further, as an example in which the treated titanium oxide is contained in the toner, JP-A-4-33773 is used.
No. 9, JP-A-4-348354 and JP-A-4-348354.
Japanese Patent No. 40467 and Japanese Patent Laid-Open No. 5-72797 also describe amorphous titanium oxide surface-treated for the purpose of imparting fluidity, stabilizing charging, preventing filming, and the like.

It has also been proposed to add hydrophobic titanium oxide to the toner. For example, JP-A-59-522
No. 55 discloses titanium oxide treated with alkyltrialkoxysilane, and in Japanese Examined Patent Publication No. 3-39307 discloses titanium oxide hydrophobized with alkyltrialkoxysilane having an alkyl group having 6 to 8 carbon atoms. Although proposed, the addition of titanium oxide has certainly improved the electrophotographic characteristics of the toner, but the surface activity of titanium oxide is inherently small compared to silica, etc., and it is hydrophobic to the target level. Of the amount of the treating agent cannot be increased, or the amount of the treating agent is increased in order to increase the degree of hydrophobicity, and further, if the means of increasing the treating time is taken, coalesced particles are generated in the treatment stage, It was difficult to produce a satisfactory hydrophobic titanium oxide because the hydrophobicity was not uniform.

On the other hand, there have been many reports of improvement studies from both the toner and the carrier.

For example, Japanese Laid-Open Patent Publication No. 51-3244 proposes a non-magnetic toner intended to improve the image quality by regulating the particle size distribution. In the toner, 8 to 12
The toner mainly has a particle size of μm, and is relatively coarse.
According to the studies made by the present inventors with this particle size, it is difficult to obtain a uniform “paste” on the latent image, and 5 μm or less is 30% by number or less and 20 μm or more is 5% by number or less. From the characteristics, the particle size distribution is broad, which also tends to reduce the uniformity. In order to form a clear image using a toner having such a coarse toner particle and a broad particle size distribution, the toner particles are superposed in a thick manner to fill the gaps between the toner particles to form an apparent image. There is also a problem that it is necessary to increase the image density, and the amount of toner consumption required to obtain a predetermined image density increases.

Further, Japanese Patent Application Laid-Open No. 54-72054 proposes a non-magnetic toner having a sharper distribution than the former, but the size of particles having an intermediate weight is 8.5 to 8.5.
As a toner having a high resolution of 11.0 μm, there is still room for improvement.

JP-A-58-129437 proposes a non-magnetic toner having an average particle size of 6 to 10 μm and a maximum number of particles of 5 to 8 μm, but particles of 5 μm or less are 15% by number or less. There is a tendency that an image lacking sharpness is formed.

According to the studies by the present inventors, it has been found that toner particles of 5 μm or less clearly reproduce the contour of the latent image and have a main function of fine toner paste to the entire latent image. Was done. In particular, in the electrostatic latent image on the photoconductor, the electric field lines are concentrated in the electrostatic charge latent image, so the electric field strength is higher at the edge portion that is the contour than inside, and the quality of the toner particles gathering at this portion causes
The sharpness of the image quality is decided. According to the study by the present inventors, 5 μ
It has been found that the amount of particles of m or less is effective for solving the problem of sharpness of image quality.

Therefore, the inventors of the present invention disclosed in Japanese Patent Laid-Open No. 222222.
No. 966, the toner particles of 5 μm or less are
Although a toner containing several percent by weight has been proposed, and a considerable improvement in image quality has been achieved by this, further improved image quality is also desired.

Furthermore, in JP-A-2-877,
A toner containing 17 to 60% by number of toner particles of 5 μm or less has been proposed, which certainly stabilizes the image quality and the image density, but allows continuous production of an original image that consumes a large amount of toner, such as a photographic original. It has also been found that it is difficult to always obtain a constant image when the toner is printed by changing the particle size distribution of the toner only by taking measures as the toner.

On the other hand, as an indication of the average particle size and particle size distribution of the carrier, JP-A-51-3238, JP-A-58-144839, and JP-A-61-20464 are proposed.
There is No. 6 publication. JP-A-51-3238 refers to a rough particle size distribution. However, it does not specifically disclose the magnetic characteristics that are closely related to the developability of the developer and the transportability within the developing device. Further, in all the carriers in Examples, 250 mesh or more is about 80% by weight.
In addition, the average particle diameter is 60 μm or more.

Further, Japanese Laid-Open Patent Publication No. 58-144839 discloses only the average particle size, and the amount of fine powder which influences the carrier adhesion to the photoreceptor and the coarseness which affects the sharpness of the image. The amount of powder is referred to, and the distribution thereof is not described in detail in consideration of the characteristics of color copying. further,
Japanese Unexamined Patent Publication (Kokai) No. 61-204646 discloses a combination of a copying machine and a suitable developer as the main point of the invention, and does not specifically describe the particle size distribution or magnetic characteristics of the carrier.
Moreover, it does not even disclose why the developer is so effective in the copying machine.

Further, JP-A-49-70630 discloses that
Although the magnetic force of the carrier is described, these are about iron powder having a larger specific gravity than ferrite as the carrier material, and the saturation magnetism is also high. Although many of these iron powder carriers have been used in the past, they have a large specific gravity and are apt to cause a heavy weight of the copying apparatus and overload of driving torque, and have a large environmental dependency.

Further, the ferrite carrier described in JP-A-58-23032 is for a porous material having a lot of pores, and such a carrier is liable to have an edge effect and is durable. It is scarce and proved to be unsuitable as a color carrier.

Until now, there has been a long-felt demand for a developer capable of continuously copying an image having a large image area with a small amount of developer and satisfying the characteristic peculiar to color copying without causing an edge effect even after endurance. There is. Although developers and carriers have been studied, most of them have been proposed in consideration of black-and-white copying, and very few have been proposed for full-color copying. In addition, a carrier having the ability to continue copying an image having an image area of 20% or more, which is almost similar to a solid image, the reduction of edge effect, and the ability to maintain the uniformity of image density in one copy are Long-awaited.

Therefore, the inventors of the present invention disclosed in Japanese Patent Laid-Open No. 2812/1990.
In JP-A-80, a carrier having a narrow particle size distribution in which the amount of fine powder and the amount of coarse powder are controlled was proposed, and a carrier having improved developing characteristics was achieved.

However, as described above, there is an increasing demand in the market for high-definition and high-quality copying machines, and in the technical field concerned, the particle size of the toner should be reduced to achieve high-quality color. Attempts have been made, but as the particle size becomes finer, 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.

Therefore, attempts have been made to further reduce the diameter of the carrier for the purpose of reducing the image density and preventing the deterioration of durability by reducing the toner particle diameter, or improving the developing efficiency. However, in such a carrier, sufficient quality has not been obtained to cope with changes in the amount of charge due to the environment of the toner or durability, and high image density, high image quality, and good fog can be achieved without optimizing the toner. In reality, it is difficult to achieve all of the prevention of carrier adhesion.

[0040]

SUMMARY OF THE INVENTION An object of the present invention is to provide a color toner and a developer that solve the above problems.

That is, an object of the present invention is to provide a color toner and a developer which have clear image characteristics free from fog and have excellent durability stability without carrier adhesion.

A further object of the present invention is to provide a color toner and a developer which are excellent in fluidity, development fidelity and transferability.

A further object of the present invention is to provide a color toner and a developer which are not easily affected by the environment such as temperature and humidity and which always have stable triboelectric charging properties.

A further object of the present invention is to provide a color toner and a developer which have good cleaning properties and have less filming or contamination on the photoreceptor.

A further object of the present invention is to provide excellent fixability,
It is to provide a color toner and a developer having excellent HP transparency.

[0046]

The present invention relates to a color toner containing at least non-magnetic colorant-containing resin particles and an external additive, the color toner being an TiO ₂ component as an external additive. ˜99.5% and Ti (OR) _m (OH) _n component 0.5 to 15% (In the formula, m and n are integers of 0 to 4, m + n = 4 is satisfied, and R is saturated or unsaturated. Saturated cyclic or acyclic hydrocarbon group) is used as a main component, and the surface of the fine powder is treated fine powder treated with a silane organic compound, and the color toner has a weight average particle diameter of 3 to 7 μm. The color toner contains more than 40% by number of toner having a particle size of 5.04 μm or less, 10 to 70% by number of toner having a particle size of 4 μm or less, and 8 μm.
2 to 20% by volume of the toner having the above particle size is contained, and 1
The present invention relates to a color toner containing 6% by volume or less of a toner having a particle size of 0.08 μm or more.

Further, in the present invention, the above-mentioned color toner and a carrier having a 50% average particle diameter of 20 to 45 μm and containing carrier particles smaller than 21 μm in an amount of 0.1 to 20% by volume of all carriers are contained. The present invention relates to a two-component type color developer containing a carrier containing carrier particles larger than 43 μm in an amount of 3 to 40% by volume of all carriers.

The present inventors have diligently studied the fluidity, charge stability, highlight reproducibility, transferability, cleaning ability and the like of the toner. As a result, the fine powder of the above composition as an external additive has a fluidity. It has been found that it is extremely excellent in terms of imparting and stabilizing charging, and in particular, is extremely effective in maximizing the performance of the fine particle toner having a specific particle size distribution as described above. It is a thing.

Further, when the diameter of the toner is further reduced, the adhesive force to the surface of the photoconductor is generally increased, and in the usual cleaning means, the so-called transfer residual toner remaining on the surface of the photoconductor after the transfer step is cleaned by a cleaning means such as a blade. It was difficult to sufficiently scrape off the surface with the toner, and cleaning defects were often found on the image. However, in the toner to which the treated fine powder of the present invention is externally added, the adhesion to the surface of the photoconductor is also extremely reduced. It has been found that it functions extremely effectively in terms of improvement of cleaning property and prevention of filming of toner on the photoconductor.

This cannot be achieved by the generally known inorganic fine powder such as titanium oxide as a fluidity imparting agent.

The reason for this is that the conventional titanium oxide production method requires a sintering, hydrolysis or thermal decomposition step at a high temperature, so that the particles are easily coarsened, and the obtained titanium oxide particles are anatase or rutile. It becomes easy to take the crystal structure of the mold.

On the other hand, the TiO ₂ component and Ti (OR) _m
(OH) _n component (wherein, m and n are integers of 0 to 4, m + n = 4 is satisfied, and R represents a saturated or unsaturated cyclic or acyclic hydrocarbon group) as a main component With the fine powder of the composition described below, coarsening of the particles is suppressed, the primary particles are less likely to coalesce with each other, and it becomes possible to impart good fluidity to the colorant-containing resin particles. It is possible to provide a high-quality toner image having excellent reproducibility and highlight reproducibility.

In addition, since the fine powder used in the present invention contains a titanium alkoxide and a titanium hydroxy component, the activity T on the fine powder surface is higher than that of ordinary rutile type, anatase type or amorphous titanium oxide particles.
The i-OH group is much larger, and therefore, when it is dispersed in the colorant-containing resin particles, it exhibits good dispersibility, and when it is attached to the surface of the colorant-containing resin particles, the binder resin and the fine powder are added. It has high body adhesion and does not contaminate the carrier particle surface or the photosensitive drum due to desorption of fine powder from the colorant-containing resin particle surface due to durability, and maintains the initial characteristics for a long time even in long-term durability. It is possible.

The treated fine powder used in the present invention is T
Since it has an iO ₂ component and a Ti (OR) _m (OH) _n component, when the toner and the carrier in which the treated fine powder is dispersed in the colorant-containing resin particles are triboelectrically charged, the Ti (OR) in the treated fine powder is _{The m} (OH) _n component serves as a kind of leak point and suppresses excessive charging. In particular, it greatly functions to suppress an excessive charge amount under low temperature and low humidity, and a stable charge amount can be obtained. Particularly when a polyester resin is used as the binder resin, the effect is great.

Further, when the particle size of the colorant-containing resin particles is reduced, the effect is remarkable.

Furthermore, since the treated fine powder used in the present invention has small primary particles and very few secondary aggregates, it contains a colorant when used in a color toner for forming a full-color image. OHP can be added externally to resin particles uniformly, has excellent optical transparency in visible light, and has a clear OHP.
An image is obtained. This is something that cannot be achieved with conventional titanium oxide particles.

Further, when the surface of the fine powder is treated with, for example, a silane-based organic compound, conventional rutile type, anatase type or amorphous titanium oxide fine particles have less active Ti-OH groups on the surface and are sufficiently treated. What could not be achieved is that in the fine powder used in the present invention, T in the fine powder is
The reaction between the i (OR) _m (OH) _n component and the treatment agent proceeds smoothly, and the surface can be uniformly treated without forming aggregates. You can raise it to the level you want to. This makes it possible to favorably stabilize the charge under high temperature and high humidity.

In the present invention, in particular, a TiO ₂ component and Ti produced by thermally decomposing a volatile titanium compound such as a titanium alkoxide in the gas phase at a temperature of 600 ° C. or lower, preferably at a relatively low temperature of 200 to 400 ° C. (OR) _m (O
H) Fine powder of a composition containing the _n component as a main component is preferable.

Particularly, the volatile titanium compound is vaporized or atomized at a relatively low temperature of 200 to 400 ° C., and then hydrolyzed (or pyrolyzed) in the presence of heated steam to decompose. Immediately thereafter, it is preferable to cool the particles to a temperature (preferably 100 ° C. or lower) at which the particles do not coalesce again in the shortest possible time.

By the above means, fine powder having a fine primary particle diameter can be obtained.

A more detailed description will be given.

That is, the inventors of the present invention conducted various studies to suppress coarsening of the fine powder and produce fine powder having less cohesiveness. As a result, not only the TiO ₂ component but also Ti (OR)
_In the case of a composition in which the _m (OH) _n component is an essential component, the crystallization of titanium oxide is suppressed, the particles become finer in particle size, the shape becomes more spherical, and Ti −
The present invention was found by finding that the OH group is displaced in the direction of increasing the number.

This cannot be achieved by using rutile type or anatase type titanium oxide or amorphous titanium oxide.

Above all, the TiO ₂ component and Ti used in the present invention
The fine powder of the composition containing the (OR) _m (OH) _n component as the main component is composed of TiO ₂ component 85 to 99.5 wt% Ti (OR) _m (OH) _n component 0.5 to 15 wt% It is preferable to have

That is, when the TiO ₂ component is less than 85%, a large amount of titanium alkoxide and titanium hydroxy component remains, or a system containing a large amount of impurities is applicable to this, and a sharp particle size distribution is obtained. It is difficult to produce a fine powder having the above, and the individual particles are likely to have a non-uniform composition, and the toner containing the fine powder as described above has a broad charge amount distribution when charged with carrier particles. It is difficult to achieve uniform development and high transfer rate.

On the other hand, when the content of TiO ₂ is more than 99.5% by weight, the fine powder approaches the pure titanium oxide particles as much as possible, the crystal structure is easily taken, and the particles tend to become coarse. With this, it is not easy to obtain the desired good fluidity.

Further, the Ti (OR) _m (OH) _n component is 0.
When it is less than 5% by weight, the dispersibility of the treated fine powder in the colorant-containing resin particles is lowered, and particularly when the treated fine powder is adhered to the surface of the colorant-containing resin particles (when the treated fine powder is externally added).
Desorption from the colorant-containing resin particle surface easily occurs,
It becomes easy to cause carrier contamination and drum contamination. In particular, when the carrier surface is contaminated, the toner charge amount is greatly reduced, toner scattering and fog during endurance are deteriorated, and it becomes difficult to secure a constant image density. Further Ti
When the content of the (OR) _m (OH) _n component is less than 0.5% by weight, the fine powder tends to coarsen, and it becomes difficult to improve the fluidity of the toner to a target level.

On the other hand, the Ti (OR) _m (OH) _n component is 15
When the content is more than wt%, a system in which hydrolysis or thermal decomposition has not progressed to a target level is applicable to this, and the composition itself of the fine powder becomes widely varied. In this case, it is not easy to generate a toner having a stable tribo distribution that is electrostatically stable. In particular, both the titanium alkoxy component and the titanium hydroxy component have much stronger properties of adsorbing water than the titanium oxide component. Therefore, when the Ti (OR) _m (OH) _n component is more than 15% by weight, the temperature and humidity are high. In the environment, the amount of charge tends to be insufficient,
Toner scattering, fog, and the like are likely to occur during durability.

Furthermore, if the Ti (OR) _m (OH) _n component is 15
If the amount of the fine powder is more than 5% by weight, the cleaning property may be deteriorated and a defective cleaning mark may be generated on the image. This is because the surface of the photoreceptor is finely divided (especially Ti (O
It is presumed that this is because R) _m (OH) _n is contaminated with fine powder containing a larger amount of component), and the releasability of the toner from the photoconductor is significantly reduced.

Therefore, in the present invention, the treated fine powder has a Ti (OR) _m (OH) _n component of 0.5 to 15% by weight, preferably 1.0 to 12% by weight, more preferably 1.5 to
Those containing 10% by weight are preferable.

The composition ratio of the TiO ₂ component and the Ti (OR) _m (OH) _n component is determined by the following procedure.

First, the fine powder is left for 3 days at 60 ° C. in a vacuum dryer and dried under reduced pressure to quantify the water content.

Next, an elemental analyzer EA- manufactured by Carlo Erba Co.
At 1108, the amount of C and the amount of H are calculated, and from these values, the composition ratio of the TiO ₂ component and the Ti (OR) _m (OH) _n component is calculated.

Compounds other than TiO ₂ are Ti (O
It is confirmed by FT-IR analysis that the compound is represented by R) _m (OH) _n (m + n = 4), and after drying under reduced pressure, the components other than the above two compounds are in trace amounts, Can be ignored.

In addition to titanium alkoxides such as titanium tetramethoxide, titanium tetraethoxide, titanium tetrapropoxide, titanium tetrabutoxide and diethoxytitanium oxide, as raw materials for the fine powder used in the present invention,
Tetrahalogenated titanium compounds such as titanium tetrachloride and titanium tetrabromide, and volatile titanium compounds such as trihalogenated monoalkoxytitanium, dihalogenated dialkoxytitanium and monohalogenated trialkoxytitanium can also be used.

When vaporizing or atomizing the volatile titanium compound, it is preferable to dilute the volatile titanium compound with a diluent gas to a ratio of 0.1 to 10% by volume. The diluent gas serves as a carrier gas for introducing the vaporized volatile titanium compound into a decomposition furnace for decomposing.

Here, as the diluting gas, argon gas,
An inert gas such as helium gas or nitrogen gas, water vapor or oxygen is used. Particularly, it is preferable to use helium gas and / or nitrogen gas. Further, if necessary, a dispersion aid, a surface modifier and the like may be added.

In the present invention, since the volatile titanium compound is decomposed after being vaporized or atomized, an oxygen-containing gas is required except for the use of an oxygen-containing compound such as alkoxide.

The decomposition temperature is preferably 600 ° C. or lower, more preferably 200 to 400 ° C., particularly preferably 250 to 350 ° C. At temperatures below 200 ° C, it is difficult to obtain a sufficient decomposition rate, while at temperatures above 600 ° C, it is difficult to obtain fine fine powder.

Further, in the present invention, it is preferable to rapidly cool to a temperature at which they do not coalesce immediately after decomposition so that the fine powders produced do not coalesce again in the gas phase. The rapid cooling prevents coalescence of the fine powders, and the fine powders thus obtained can be collected and collected in the form of primary particles.

Next, the surface treatment which is another feature of the present invention will be described.

The present invention is also characterized in that the fine powder surface is surface-treated with a silane organic compound in order to adjust the charging characteristics and improve the stability under high humidity.

Particularly, as described above, after the fine powder which becomes the core is formed by the vapor phase method, immediately after the fine powder is mixed with the vaporized or atomized silane organic compound, the surface treatment is continuously carried out in the vapor phase. Is preferred.

The TiO ₂ component and Ti proposed by the present inventors
The fine powder of the composition containing the (OR) _m (OH) _n component as the main component has much higher surface activity than that of pure titanium oxide, that is, T which can react with a silane-based organic compound.
Since the i-OH group is contained in a larger amount, it is advantageous for the reaction, and it can be uniformly treated with a small amount of a treating agent to increase the degree of hydrophobicity. Especially when the surface treatment is performed in the gas phase, unlike the conventional wet treatment, the surface treatment can be performed without taking steps such as filtration, drying and crushing, so that the characteristics of the fine powder before treatment are not impaired and uniform. Moreover, it becomes possible to sufficiently perform the surface treatment.

The treatment amount and treatment time of the silane-based organic compound with respect to the fine powder of the composition containing the TiO ₂ component and Ti (OR) _m (OH) _n as the main components are not particularly limited. The amount of Si in terms of SiO ₂ of the treated fine powder of is preferably 1 to 18% by weight, more preferably 1.5 to
It is preferable that the surface of the fine powder is treated with a silane-based organic compound so that the content of the fine powder is 16% by weight, more preferably 2.5 to 14% by weight.

When the amount of Si in terms of SiO _{2 of the} treated fine powder is lower than 1% by weight, it means that the treatment is not sufficient or the treatment is not successful for some reason. There is a tendency that density increase under high temperature and high humidity, toner scattering during endurance, fog and the like deteriorate. Further, when the amount of Si in terms of SiO ₂ exceeds 18% by weight, this corresponds to the case where the amount of the silane-based organic compound treated is extremely large, which corresponds to a fine powder having a small primary particle size and a small cohesiveness. Is not easy to generate, and it becomes a treated fine powder with a lot of aggregates, and it is not easy to impart good fluidity to the toner. Due to the removal of the processing agent which could not sufficiently react with the surface of the fine powder of the base material, a toner image with a lot of fog and rubbing tends to be generated.
Further, this causes a new problem of carrier contamination.

As described above, the fine powder of the composition containing the TiO ₂ component and Ti (OR) _m (OH) _n of the present invention as the main components is much finer than the conventional titanium oxide. It has a large amount of Ti-OH groups in it, and therefore has a high surface activity, and is advantageous for the reaction with a silane-based organic compound, and it is possible to uniformly treat the fine powder surface with a small amount of a treating agent to enhance the degree of hydrophobicity. .

In addition, when the treatment is carried out in the gas phase, it is possible to increase the amount of Si in terms of SiO ₂ without forming secondary aggregates. This is something that cannot be achieved by other treatment methods, for example, wet treatment. Increasing the treating agent amount added trying simply to increase the amount of Si in terms of SiO ₂ in conventional wet processing method other words, although it is possible to increase the Si content itself in terms of SiO _2, the particles of the just fine powder As a result, the BET specific surface area is low and the apparent primary particle size tends to be large as compared with before the treatment.

On the other hand, in the case of the vapor phase treatment method, the amount of Si in terms of SiO ₂ can be increased with almost no change in the value of BET specific surface area before and after the treatment and while maintaining the primary particle diameter of the base material.

In the present invention, the fluorescent X-ray spectroscopic analysis method is used to measure the amount of Si in terms of SiO ₂ .

The silane-based organic compound used in the present invention may be appropriately selected depending on the purpose of surface modification, for example, control of charging characteristics, and stabilization and reactivity of charging under high humidity. For example, compounds such as alkylalkoxysilanes, siloxanes, silanes, and silicone oils, which do not thermally decompose themselves at the reaction processing temperature, are preferable.

Particularly preferred is an alkylalkoxysilane represented by the following general formula, which is volatile such as a coupling agent and has both a hydrophobic group and a bonding group rich in reactivity. Good to use.

R _m SiY _n [wherein R represents an alkoxy group, m represents an integer of 1 to 3, Y represents a hydrocarbon group such as an alkyl group, a vinyl group, a glycidoxy group or a methacryl group, and n Represents an integer of 1 to 3]

For example, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxy. Examples thereof include silane, trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-hexadecyltrimethoxysilane, and n-octadecyltrimethoxysilane.

More preferably, the formula C _a H _{2a + 1} -Si-
(OC _b H _{2b + 1} ) ₃ [wherein a represents an integer of 4 to 12,
b represents an integer of 1 to 3] is preferable.

When a in the general formula is smaller than 4, the treatment is easy, but good hydrophobicity is difficult to obtain.
If a is greater than 13, the hydrophobicity will be sufficient, but the coalescence of the fine powders will increase and the fluidity imparting ability will tend to decrease.

If b is larger than 3, the reactivity is lowered and it is difficult to obtain good hydrophobicity.

Therefore, in the present invention, a is preferably 4-12, more preferably 4-8, and b is preferably 1-3, more preferably 1-2.

Further, the treated fine powder in the present invention has an average particle size of preferably 0.005 to 5 from the viewpoint of imparting fluidity.
0.1 μm, and more preferably 0.01 to 0.05 μm.

When the average particle size is larger than 0.1 μm, the fluidity is lowered and the toner is apt to be non-uniformly charged, resulting in toner scattering and fogging, which makes it difficult to form a high quality toner image. . The average particle size is 0.0
If it is less than 05 μm, the treated fine powder is likely to be embedded in the surface of the colorant-containing resin particles, the toner is likely to deteriorate quickly, and the durability is likely to be deteriorated. This tendency is more remarkable than when it is applied to a color toner having a sharp melt property.

The particle size of the treated fine powder in the present invention is measured by a transmission electron microscope.

Next, the particle size distribution of the toner will be described.

The inventors of the present invention have earnestly studied the image density, highlight reproducibility, fine line reproducibility, etc. of the developer.
When the weight average particle diameter of the toner is 3 to 7 μm, the toner can be faithfully developed with respect to the latent image on the photosensitive member.
It has been found that the amount of particles of μm or less greatly contributes particularly to the improvement of highlight reproducibility.

That is, the weight average particle diameter of the toner is 7 μm.
A larger value basically means that there are few fine particles that can contribute to high image quality, and although it is easy to obtain a high image density and the toner has excellent fluidity, it is possible to obtain a fine latent image on the drum. It is difficult to adhere faithfully to the image, the highlight reproducibility is poor, and sufficient resolution cannot be obtained. Further, there is also a tendency that excessive development, that is, toner is overloaded, which tends to cause an increase in toner consumption.

On the contrary, when the weight average particle diameter of the toner is smaller than 3 μm, it means that the charge amount per unit weight of the toner becomes extremely high, and the density is low, particularly the image density is low at low temperature and low humidity. . This is not suitable for applications with a high image area ratio such as graphic images.

When the particle size is smaller than 3 μm, the contact charging with the carrier is not smoothly carried out, the amount of toner which cannot be sufficiently charged increases, and scattering to the non-image area, that is, fog becomes conspicuous. In order to deal with this, it is possible to reduce the diameter of the carrier in order to increase the specific surface area of the carrier,
A toner having a weight average particle diameter of less than 3 μm easily causes toner self-aggregation, uniform mixing with a carrier is not achieved in a short time, and fog toner tends to occur inevitably in continuous toner replenishment durability.

Therefore, in the present invention, the weight average particle diameter of the toner is preferably 3 to 7 μm.

Based on what has been described so far, the toner of the present invention contains toner particles having a particle diameter of 4 μm or less in an amount of 10 to 70% by number, preferably 15 to 60% by number based on the total number of particles. If the number of toner particles having a particle diameter of 4 μm or less is less than 10% by number, it means that there are few fine toner particles which are essential components for high image quality. As it is continuously used, the effective toner particle component decreases, the balance of the toner particle size distribution shown in the present invention deteriorates, and the image quality tends to gradually deteriorate.

Toner particles having a particle diameter of 4 μm or less are 70
If it exceeds the number%, the toner particles are likely to aggregate with each other and often act as a toner lump having a particle size larger than the original particle size, resulting in a rough image or a reduction in resolution, or The density difference between the edge portion and the inside of the latent image becomes large, and the image tends to have a hollow image, which is not preferable.

Particles having a size of 8 μm or more are preferably 2 to 20% by volume, and more preferably 3.0 to 18.0% by volume. If it is more than 20% by volume, the image quality will deteriorate and
Unnecessary development, that is, toner overload occurs,
This leads to an increase in toner consumption. On the other hand, if the content is less than 2% by volume, the image quality may be deteriorated due to the deterioration of fluidity, no matter how the toner formulation is devised.

In order to further improve the effect of the present invention, for the purpose of improving the chargeability and fluidity of the toner,
Particles of 5.04 μm or less are more than 40% by number and 90% by number or less, preferably more than 40% by number and 80% by number or less, and particles of 10.08 μm or more are 0 to 6% by volume, preferably 0 to 4%. It is necessary to set the volume%.

In particular, in order to make full use of the fine particle toner of the present invention, improvement of fluidity and stabilization of charging are important points, and a good image cannot be expected even if either of them is lacking.

Therefore, in order to maximize the potential of the fine particle toner having the above-mentioned particle size distribution and achieve high resolution and high gradation, the fine powder having a large fluidity imparting ability as described above is externally added. It is indispensable to use the above, and a good image can be obtained only by combining the two.

Further, as the toner is made finer, the charge per toner becomes smaller and the toner tends to scatter in general. However, the fine powder of the present invention has a high charge imparting ability, improves the fluidity and stabilizes the charge. Both can be achieved. This has never been achievable with other external additives.

The constituent materials of the toner of the present invention will be described in detail below.

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

For example, styrene-based copolymers such as polystyrene, styrene-butadiene copolymer, styrene-acryl copolymer, etc., ethylene-based such as polyethylene, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer. Examples thereof include copolymers, phenol resins, epoxy resins, acrylic phthalate resins, polyamide resins, polyester resins, maleic acid resins and the like. In addition, the manufacturing method and the like of each resin are not particularly limited.

Of these resins, the effect of the present invention is remarkable 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, they have a strong negative charging ability and are prone to excessive charging, but when the polyester resin is used in the constitution of the present invention, the harmful effects are improved and excellent. Toner is obtained.

In particular, the following equation

[0120]

Embedded image

(Wherein R is an ethylene or propylene group, x and y are each an integer of 1 or more, and x +
The average value of y is 2 to 10. ), A bisphenol derivative or a substitution product represented by the formula (1) is used as a diol component, and a carboxylic acid component composed of a carboxylic acid having a valence of 2 or more or an acid anhydride thereof or a lower alkyl ester thereof (eg, fumaric acid, maleic acid, maleic anhydride, phthalate). An acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc.) is more preferable because it has a sharp melting property.

Examples of the colorant used in the present invention include dyes and pigments known as non-magnetic toner, for example, phthalocyanine blue, indanthrene blue, peacock blue, permanent red, lake red, rhodamine lake, Hansa yellow, permanent yellow, Benzidine yellow or the like can be used. As its content,
In order to sensitively reflect the transparency of the OHP film, it is 12 parts by weight or less, preferably 0.5 to 9 parts by weight, based on 100 parts by weight of the binder resin.

The toner of the present invention is not limited to the negative charging property and the positive charging property, but in the case of producing the negative charging toner, a charge control agent is added particularly for the purpose of stabilizing the negative charge characteristic. Preferably. Examples of the negative charge control agent include organometallic complexes such as metal complexes of alkyl-substituted salicylic acid (eg, chromium complex or zinc complex of di-tert-butylsalicylic acid).

When a positively chargeable toner is prepared, nigrosine, a triphenylmethane compound, a rhodamine dye, polyvinyl pyridine or the like may be used as the charge control agent exhibiting the positive chargeability. Further, in the case of producing a color toner, it is desirable to use a colorless or pale color positive charge control agent that does not affect the color tone of the toner.

If necessary, the toner of the present invention may be mixed with an additive as long as the characteristics of the toner are not impaired. Examples of such additives include organic resin particles, charging aids such as metal oxides, lubricants such as Teflon, zinc stearate and polyvinylidene fluoride, or fixing aids (eg low molecular weight polyethylene, low molecular weight polypropylene). Etc.).

To prepare the colorant-containing resin particles according to the present invention, a thermoplastic resin, if necessary, a pigment or dye as a colorant, a charge control agent, other additives, etc. are sufficiently mixed by a mixer such as a ball mill. After mixing, melt using a heat kneader such as heating roll, kneader, extruder.
Disperse or dissolve the pigment or dye in the kneading and kneading meat to make the resins compatible with each other, and after cooling and solidification, pulverization and strict classification are performed to obtain the colorant-containing resin particles according to the present invention. You can

Next, the carrier used in the present invention will be described.

The carrier used in the present invention has a small average particle size and is a uniform small particle size carrier having a uniform particle size in which the amounts of fine powder and coarse powder are controlled. Therefore, the rise of the triboelectric chargeability with the toner having a reduced particle size is also preferably improved. However, the carrier of the present invention has a much larger amount of fine powder than the conventionally known carriers, and there is concern about carrier adhesion on the latent image holding member during development. By combining them, not only carrier adhesion does not occur, but also it becomes possible to obtain a good highlight image without roughness.

The reason for this is not clear yet, but it is presumed as follows.

That is, since the carrier of the present invention has a smaller particle size than the conventional carrier, the flowability of the carrier itself is lowered, and the developer in the developing area is liable to form a magnetic brush. However, by combining with the toner of the present invention, the charging is uniform, the fluidity as a developer is improved, and a dense magnetic brush is formed to improve the image quality, and at the same time, the contact of the magnetic brush with the latent image carrier is prevented. The impact is softened and carrier adhesion is improved.

From the above, by using the developer under the above conditions, the reproducibility of dots in the highlight latent image is improved and the roughness is improved. Further, since the magnetic brush in the developing area becomes dense, a uniform halftone and solid image without unevenness due to the contact state can be achieved.

A more detailed description will be given.

The carrier has a 50% average particle size of 20 to 45 μm, and carrier particles smaller than 21 μm are 0.1 to 20% by volume, preferably 0.5 to 15% by volume, of 43 μm. Large carrier particles account for 3-40% by volume of total carrier, preferably 5-30
Volume% is preferable.

If the amount of the fine powder present exceeds the above range, even if the fine powder is combined with the specific toner of the present invention, the adhesion of the carrier and the smooth charging of the toner are hindered and a good image cannot be obtained. . Further, the fluidity of the developer is extremely lowered, and the mixing is not sufficiently performed in a short time, which causes toner scattering and fog.

On the other hand, the amount of coarse powder of the carrier of 43 μm or more closely correlates with the sharpness of the image, and is 3 to 4 of all carriers.
It should be 0% by volume. If it exceeds 40% by volume, the carrier toner transporting ability is lowered, the toner is scattered to the non-image portion, the resolution of the image is lowered, and the highlight reproducibility is lowered. When the content is less than 3% by volume, the flowability of the developer is deteriorated, the developer is biased in the developing device, and it is difficult to obtain a stable image.

Further, in order to make the effect of the present invention more effective, the apparent density of the carrier is 1.0 to 2.7 g.
/ Cm ³ is preferable. If the apparent density is smaller than the above value, carrier adhesion is likely to occur, and if it is larger than the above value, the circulation of the developer is deteriorated, toner scattering is likely to occur, and the image quality is deteriorated earlier. Will end up.

The carrier used in the present invention is, for example, surface-oxidized or unoxidized iron, nickel, copper, zinc,
Metals such as cobalt, manganese, chromium, rare earths, their alloys or oxides and ferrites can be used. In addition, there is no particular limitation on the manufacturing method.

As a method of coating the surface of the carrier with a resin or the like, a method of dissolving or suspending a coating material such as a resin in a solvent and applying the coating material onto the carrier,
Any conventionally known method such as a method of simply mixing with powder can be applied.

The substance adhered to the surface of the carrier varies depending on the toner material. For example, polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, metal complex of tert-butyl salicylic acid, and styrene type. Resin, acrylic resin, polyamide, polyvinyl butyral, nigrosine, amino acrylate resin, basic dye and its lake, fine silica powder, fine alumina powder and the like are suitable, but are not necessarily limited to these. Not done.

The amount of the above-mentioned compound to be treated may be appropriately determined so that the carrier satisfies the above conditions, but generally, the total amount is 0.1 to 30% by weight (preferably 0.
5 to 20% by weight) is preferable.

The magnetic characteristics of the carrier are influenced by the magnet roller incorporated in the developing sleeve, and greatly affect the developing characteristics and the transportability of the developer.

In the present invention, on the developing sleeve having a built-in magnet roller, the magnet roller is fixed and the developing sleeve is rotated by itself to circulate and convey the two-component developer consisting of magnetic particles and insulating color toner. When the electrostatic latent image carried on the surface of the electrostatic latent image carrier is developed with the two-component developer, the magnet roller has a five-pole structure having a repulsive pole, and the magnetic flux density in the developing region is 600 to When the carrier has a saturation magnetization of 35 to 90 emu / g, the uniformity of the image and the gradation reproducibility in color copying are excellent and suitable.

When the saturation magnetization exceeds 90 emu / g (for an applied magnetic field of 3000 oersteds), the brush composed of the carrier and the toner on the developing sleeve facing the electrostatic latent image on the photoreceptor during development. -Like spikes are tightly tightened, and the reproduction of gradation and halftone is poor. If it is less than 35 emu / g, it becomes difficult to properly hold the toner and the carrier on the developing sleeve, and problems such as carrier adhesion and toner scattering are likely to occur. Further, if the residual magnetization and coercive force of the carrier are too high, the good transportability of the developer in the developing device is hindered, and image defects such as scratches and uneven density in a solid image are likely to occur, and the developing ability is deteriorated. It will be lowered. Therefore, in order to maintain the developability in color copying, which is different from general black-and-white copying, the residual magnetization thereof is 10 emu / g or less, preferably 5 emu / g or less,
More preferably, it is substantially 0, and the coercive force is 40 oersted or less (3000 oersted, with respect to the applied magnetic field),
Preferably 30 oersted or less, more preferably 10
It is important to be less than or equal to Oersted.

When a two-component developer is prepared by mixing with the toner of the present invention, the mixing ratio is 2% by weight to 15% by weight, preferably 3% by weight to 13% by weight, as toner concentration in the developer. More preferably 4% to 10% by weight
A good result is usually obtained. Toner concentration is 2%
When it is less than 15%, the image density is too low to be practically applicable, and when it exceeds 15%, fog and scattering in the machine are increased and the useful life of the developer is shortened.

The measuring method of each characteristic value will be described below.

Measurement of toner particle size distribution As a measuring device, Coulter Counter TA-II or Coulter Multisizer II (manufactured by Coulter Co.)
To use. As the electrolytic solution, about 1% NaCl aqueous solution is prepared using first-grade sodium chloride. For example, ISOTON
-II (made by Coulter Scientific Japan) can be used. As a measuring method, a surfactant (preferably an alkylbenzene sulfonate) as a dispersant in 100 to 150 ml of the electrolytic aqueous solution is added in an amount of 0.1 to 0.1 ml.
5 ml is added, and 2 to 20 mg of the 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 the volume and the number of toner particles are measured for each channel by using the measuring device with a 100 μm aperture as an aperture. Then, the volume distribution and the number distribution of the toner are calculated. Then, the weight-based toner weight average particle diameter (D4) (the median value of each channel is used as a representative value for each channel) obtained from the volume distribution of the toner particles is obtained.

The channels are 2.00 to 2.52.
μm; 2.52 to 3.17 μm; 3.17 to 4.00 μm
m; 4.00 to 5.04 μm; 5.04 to 6.35 μ
m; 6.35 to 8.00 μm; 8.00 to 10.08 μm
m; 10.08-12.70 μm; 12.70-16.
00 μm; 16.0-20.20 μm; 20.20
25.40 μm; 25.40-32.00 μm; 32.
13 channels of 00-40.30 μm are used.

Measurement of Carrier Particle Size Distribution As a measuring device, a laser diffraction type particle size distribution measuring device HE is used.
LOS (manufactured by JEOL Ltd.) is equipped with a dry dispersion device RODOS (manufactured by JEOL Ltd.), and each sample is measured three times under the condition of a dispersion pressure of 3.0 bar, and the average is taken to obtain the carrier particle size distribution. And The average particle size in the present invention was 50%.

[0149]

EXAMPLES Examples of the present invention will be described below.
All parts are parts by weight.

Synthesis Example 1 of Treated Fine Powder Titanium tetraisopropoxide was used as a raw material. Titanium tetraisopropoxide was fed little by little by a chemical pump into an evaporator heated to 200 ° C. using nitrogen gas as a carrier gas to completely vaporize titanium tetraisopropoxide. On the other hand, water was sent to the evaporator together with nitrogen gas which is a carrier gas using a chemical pump to vaporize and further heat, and then at a temperature of 280 ° C. in the reactor together with the vaporized titanium tetraisopropoxide. After thermal decomposition, using nitrogen gas as a carrier gas, isobutyltrimethoxysilane, which is a surface treatment agent, was sent to an evaporator by a chemical pump to be completely vaporized, and nitrogen powder containing the fine powder and heated steam synthesized previously was added. The mixture was mixed with a flow, reacted at 280 ° C., subjected to hydrophobic treatment and simultaneously cooled rapidly to collect the treated fine powder-A whose surface was modified with isobutyltrimethoxysilane.

Comparative Synthesis Example 1 of Fine Powder An untreated fine powder-B was obtained in the same manner as in Synthesis Example 1 except that the hydrophobic treatment was not performed with isobutyltrimethoxysilane.

Synthesis Example 2 of treated fine powder A treated fine powder-C surface-modified in the same manner as in Synthesis Example 1 was obtained except that propyltrimethoxysilane was used instead of isobutyltrimethoxysilane.

Synthesis Example 3 of Treated Fine Powder Titanium tetranormal propoxide was used instead of titanium tetraisopropoxide, and the temperature of the evaporator was set to 220.
A surface-modified treated fine powder-D was obtained in the same manner as in Synthesis Example 1 except that the temperature of the reactor was 300C and the temperature of the reactor was 300C.

Comparative Synthesis Example 2 of Fine Powder An untreated fine powder-E was obtained except that the isobutyltrimethoxysilane used in Synthesis Example 1 in Synthesis Example 3 was not used.

Synthesis Example 4 of Treated Fine Powder A coupling agent (normal butyltrimethoxysilane) was added to the above fine powder while stirring and mixing the untreated fine powder-B obtained in Comparative Synthesis Example 1 in an aqueous system. The mixture was added and mixed so as to be in a weight percentage and particles were not united, dried and crushed to obtain a surface-modified treated fine powder-F.

Synthetic Example 5 of treated fine powder In the Synthetic Example 1, the surface-modified treatment was carried out in substantially the same manner as in Synthetic Example 1 except that the supply amount of titanium tetraisopropoxide as a raw material was increased and the rapid decomposition was not carried out after thermal decomposition. Fine powder-G was obtained.

[0157] was carried out fine powder also synthesized composition analysis only did not surface modification in the same manner, TiO ₂ component 9
The content was 0.2% by weight, and the Ti (OR) _m (OH) _n component was 7.2% by weight.

Comparative Synthesis Example 3 of Fine Powder Titanium tetrachloride was decomposed by heating in a gas phase at 800 ° C. to obtain Fine Powder-H.

Comparative Synthesis Example 4 of Fine Powder A fine powder-I was obtained by neutralizing the fine powder in an aqueous solution of titanium sulfate and then producing the resulting precipitate by the sulfuric acid method.

Comparative Synthesis Example 5 of Treated Fine Powder The fine powder-H obtained in Comparative Synthesis Example 3 was hydrophobized with octyltrimethoxysilane by a wet method to obtain a treated fine powder-J.

Synthesis Example 6 of Treated Fine Powder A treated fine powder-K was obtained in the same manner as in Synthesis Example 1 except that the supply amount of isobutyltrimethoxysilane was extremely reduced.

Synthesis Example 7 of Treated Fine Powder A treated fine powder-L was obtained in the same manner as in Synthesis Example 1 except that the temperature of thermal decomposition was 200 ° C. and the amount of water fed into the reactor was reduced. . Similarly, fine powder that had not been surface-treated was also synthesized and its composition was analyzed.
The content of the _two components is 86.0% by weight and Ti (OR)
The content of the _m (OH) _n component was 12.7% by weight.

Synthetic Example 8 of treated fine powder In the same manner as in Synthetic Example 1, except that the temperature of thermal decomposition was further lowered from 280 ° C. to 170 ° C. and the feed amount of titanium tetraisopropoxide as a raw material was increased. Fine powder-M was obtained.

Similarly, fine powder which had not been surface-treated with isobutyltrimethoxysilane was synthesized, and the composition was analyzed. As a result, the content of TiO ₂ component was 82.7% by weight, and Ti (OR) _m The content of (OH) _n component is 1
It was 5.1% by weight.

[0165]

[Table 1]

Example 1 • Polyester resin obtained by condensing 100 parts of propoxylated bisphenol and fumaric acid • Phthalocyanine pigment 4 parts • Chromium complex salt of di-tert-butylsalicylic acid 4 parts

The above materials were sufficiently premixed by a Henschel mixer, melt-kneaded by a twin-screw extruder, cooled, roughly crushed to about 1 to 2 mm by a hammer mill, and then finely crushed by an air jet system. Finely crushed with.
The finely pulverized product obtained was further classified to have a weight average particle diameter of 6.0 μ.
m colorant-containing resin particles (I) were obtained.

Cyan toner was prepared by mixing the colorant-containing resin particles and 1.2% by weight of the hydrophobized fine powder A of Synthesis Example 1 with a Henschel mixer. This cyan toner is
The weight average particle diameter was 6.0 μm. When the treated fine powder on the colorant-containing resin particles was observed by SEM, it was confirmed that the particles were uniformly adhered to the toner surface in the state of almost primary particles.

50% by weight of styrene and 2 parts of methyl methacrylate were added to a Cu-Zn-Fe ferrite carrier.
A copolymer composed of 0% by weight and 30% by weight of 2-ethylhexyl acrylate was mixed with 93 parts of coated ferrite carrier coated with 0.5% by weight and 7 parts of cyan toner to prepare a developer. The 50% average particle size of this carrier (carrier (a)) was 33.1 μm, 2.9% by volume of the carriers smaller than 21 μm, and 15.1% by volume of the carriers in excess of 43 μm.

Using this developer, the development contrast was set to 300 V with a commercially available plain paper color copying machine (color laser copier 550, made by Canon), and 23 ° C./65%.
Drawing was performed under RH. The obtained image is X-Rite
The reflection density was measured using X-Rite 404A manufactured by the company (the same applies to the subsequent image density measuring method). The toner image density was as high as 1.58 and was clear without fog. After that, 10,000 more copies were made, but carrier adhesion did not pose a problem, and the density fluctuation during that time was 0.0
It was as small as 8, and the fog and sharpness were similar to those in the initial stage. Even under low temperature and low humidity (20 ° C./10% RH), when the development contrast was set to 300 V and images were printed, the image density was high at 1.44, and it was effective in controlling the charge amount even under low humidity. It was

When a cyan toner image was transferred onto an OHP film and fixed, the light was transmitted through an overhead project, and a clear cyan image was projected on the screen.

Even under high temperature and high humidity (30 ° C./80% RH), similarly, when the development contrast was set to 300 V and image formation was performed, the image density was 1.50, and a very stable and good image was obtained. Was given.

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

Table 3 shows toner physical properties and image characteristics (the same applies hereinafter).

Comparative Example 1 A toner and a developer were prepared in the same manner as in Example 1 except that untreated fine powder B was used, and the toner and developer were prepared under high temperature and high humidity (30 ° C./8).
When tested at 0% RH), the image density was higher than that in Example 1 and the image was more fogged overall.

Examples 2 and 3 A toner and a developer were prepared in the same manner as in Example 1 except that the surface-modified fine powders C and D were used.
When tested in the same manner as above, good results were obtained.

Comparative Example 2 A toner and a developer were prepared in the same manner as in Example 1 except that untreated fine powder E was used, and tested in the same manner as in Example 1. As a result, no problem was found in a low temperature and low humidity environment. However, in durability under high temperature and high humidity environment (30 ° C./80% RH), the image density tended to increase slightly during the standing period, and toner scattering around the developing device was also observed and the durability was interrupted. .

Example 4 Example 1 except that the surface-modified treated fine powder F is used.
A toner and a developer were prepared in the same manner as in (1) and tested in the same manner as in Example 1.

By surface treatment, high temperature and high humidity (30 ° C./80
% RH) was stable and the image density remained stable at around 1.5, but under low temperature and low humidity environment (20 ° C / 10
% RH), the image became dull with durability, and the target high-quality image was not obtained. It is considered that this is because the transferability is deteriorated due to the decrease in the fluidity of the toner. However, the image was somehow within the practical level.

Observing the toner surface with an SEM,
It was confirmed that some of the fine powders were agglomerated and attached to the surface, and it was judged that the proportion of the fine powders attached in the state of primary particles was small compared to Example 1.

Example 5 Example 1 except that the surface-modified treated fine powder G is used.
A toner and a developer were prepared in the same manner as in (1) and tested in the same manner as in Example 1.

Although the image was inferior in fine line reproducibility and halftone part reproducibility as compared with Example 1, the proportion mixed with the colorant-containing resin particles was increased from 1.2% by weight to 1.8% by weight. By doing so, the image quality was improved to a practical level.

Comparative Examples 3 and 4 Tests were carried out in the same manner as in Example 1 except that untreated fine powders H and I were used.

Only a rough image was obtained under low temperature and low humidity, and the image density became extremely high under high temperature and high humidity, and the toner was scattered from the beginning of the durability, and the durability was not evaluated.

Even if the number of copies to be added was increased, the image quality was hardly improved, but rather the level under high temperature and high humidity was deteriorated.

Comparative Example 5 A test was performed in the same manner as in Example 1 except that the untreated fine powder J was used. Compared to Comparative Examples 3 and 4, the performance under high temperature and high humidity was improved and the toner scattering was suppressed, but the image quality under low temperature and low humidity and after durability could not be improved.

Example 6 A toner and a developer were prepared in the same manner as in Example 1 except that the treated fine powder K was used, and the toner and the developer were prepared under high temperature and high humidity (30 ° C./80%).
As a result of a test with RH), the image density was higher than that in Example 1 and the image with a large amount of fog was obtained. In addition, the level of scattering deteriorated with endurance, and the flight was interrupted.

Example 7 Example 1 except that the surface-modified treated fine powder L was used.
A toner and a developer were prepared in the same manner as in (1) and tested in the same manner as in Example 1.

Although there was a tendency for the concentration to be slightly higher in a high temperature and high humidity environment, it was at a sufficiently practical level, and in a low temperature and low humidity environment, the mixing ratio with the colorant-containing resin particles was 1.2% by weight to 1.7%. The image quality could be further improved by increasing the amount to the weight percentage.

Comparative Example 6 A toner and a developer were prepared in the same manner as in Example 1 except that the surface-modified treated fine powder M was used, and tested in the same manner as in Example 1.

The mixing ratio with the colorant-containing resin particles is 0.
When the content was 5% by weight, the toner did not have sufficient fluidity, the movement of the agent in the developing device during the endurance of the toner became poor, and uneven density and improper mixing of the toner occurred. Then, when the amount of addition was variously examined, by increasing the amount from 1.2% by weight to 2.0% by weight, it became possible to obtain a practical level image in a low temperature and low humidity environment. However, under these conditions, the shortage of the charge amount under high temperature and high humidity was remarkable, and toner scattering and fog were conspicuous from the initial stage of durability, and it was not possible to satisfy both conditions.

Example 8 Weight average particle diameter of 5.2 μm using the material described in Example 1.
The colorant-containing resin particles (II) of Example 1 were obtained in the same manner. The colorant-containing resin particles and the hydrophobized fine powder C of Synthesis Example 3
Cyan toner was similarly prepared by mixing with 1.5% by weight.

Coated ferrite carrier obtained by coating a Cu-Zn-Fe ferrite carrier with 0.5% by weight of a curable silicone resin (carrier (b): 50% average particle size is 36.0 μm, carriers smaller than 21 μm are all carriers). (3% by volume of carrier of 0.33% by volume, carrier of greater than 43 μm is 24% by volume of the total carrier) and 7 parts of cyan toner were mixed and evaluated in the same manner as a developer. The result was extremely good, and particularly the reproducibility of the halftone portion was extremely good.

Examples 9 and 10 Using 5 parts of a quinacridone pigment and 4 parts of a disazo yellow pigment instead of the phthalocyanine pigment used in Example 1, colorant-containing resin particles (III), (I
V) was obtained.

Synthetic Example 1 was added to each colorant-containing resin particle.
1.2 wt% of the hydrophobized fine powder was externally added to obtain magenta toner (weight average particle size = 5.9 μm) and yellow toner (weight average particle size = 5.8 μm).

When images were printed and evaluated in the same manner as in Example 1, good results were obtained.

Comparative Example 7 The treated fine powder A was externally added to the colorant-containing resin particles (V) having the particle size distribution shown in Table 2 in an amount of 0.6% by weight and imaged in the same manner as in Example 1. However, although the solid part is fine, the highlight part has a dull image.

Comparative Example 8 Colorant-containing resin particles having a particle size distribution shown in Table 2 (V
An image was produced in the same manner as in Example 1 except that 2.0% by weight of the treated fine powder A was externally added to I) and the toner concentration was set to 5%. It became an image.

Comparative Example 9 Colorant-containing resin particles having a particle size distribution shown in Table 2 (V
Example 1 was prepared by adding 1.0% by weight of the treated fine powder A to II).
When the image is printed in the same manner as above, the fluidity of the toner does not improve so much, and if the amount of the external additive is increased to improve the fluidity, the charge amount becomes insufficient under high temperature and high humidity. No satisfactory results were obtained. It is considered that this is a phenomenon caused by the broad particle size distribution of the toner.

[0200]

[Table 2]

[0201]

[Table 3]

Comparative Example 10 Instead of the carrier used in Example 1, a carrier (c) having the particle size distribution shown in Table 4 (the coating agent is the same as the carrier (a) used in Example 1) was used, and toner was used. Images were produced in the same manner as in Example 1 except that the developer was prepared at a concentration of 5% by weight. Development contrast of 300V at 23 ℃
In the environment of / 65%, the initial image density is as low as 1.22,
When the toner was durable with the toner density of 7% (initial image density of 1.46), toner scattering began to be noticeable from about 1000 sheets, and an image with a lot of fog was formed. When the development contrast was increased to 450 V and the toner was durable while the toner concentration was maintained at 5% by weight, the image density was raised to a level where there was no problem. The image has become particularly rough in the department.

Comparative Example 11 Instead of the carrier used in Example 1, a carrier (d) having the particle size distribution shown in Table 4 (the coating agent is the same as the carrier (a) used in Example 1) was used. Images were formed in the same manner as in Example 1 except that the developer was prepared at a concentration of 8% by weight. Deviation of the developer in the developing unit, which seems to be due to extremely low fluidity of the developer, occurs,
There was an extreme difference in the image densities on the right and left of the image. In addition, carrier adhesion was large, and the development conditions, development bias, and other conditions were tried, but the results were not fully suppressed, and durability was interrupted.

[0204]

[Table 4]

[0205]

According to the present invention, since the above-mentioned treated fine powder treated with a silane-based organic compound is used as an external additive for toner particles having a specific particle size distribution, a clear color image free from fog can be obtained. In addition, it has excellent durability stability, fluidity, transferability, and OHP transparency.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location G03G 9/08 361 372 9/10

Claims (4)

[Claims] 1. A color toner containing at least non-magnetic colorant-containing resin particles and an external additive, wherein the color toner contains, as an external additive, a TiO ₂ component of 85 to 99.5% and Ti (OR).
_m (OH) _n component 0.5 to 15% (In the formula, m and n are integers of 0 to 4, satisfying m + n = 4, and R is a saturated or unsaturated cyclic or acyclic hydrocarbon group. The composition of the present invention comprises a fine powder surface treated with a silane-based organic compound, and the color toner has a weight average particle diameter of 3 to 7 μm. The toner contains more than 40% by number of toner having a particle size of 5.04 μm or less, 10 to 70% by number of toner having a particle size of 4 μm or less, and 2 to 2% of toner having a particle size of 8 μm or more. Contains 20% by volume, 10.0
A color toner comprising 6% by volume or less of a toner having a particle diameter of 8 μm or more. 2. The color toner according to claim 1, wherein the treated fine powder is a fine powder that has been subjected to a hydrophobic treatment in a gas phase. 3. The treated fine powder has a primary particle size of 0.00
3. The color toner according to claim 1, which is in the range of 5 to 0.1 μm. 4. A two-component color developer containing at least a toner and a carrier, wherein the toner is a color toner containing at least non-magnetic colorant-containing resin particles and an external additive. The toner contains TiO ₂ component 85 to 99.5% and Ti (OR) as external additives.
_m (OH) _n component 0.5 to 15% (In the formula, m and n are integers of 0 to 4, satisfying m + n = 4, and R is a saturated or unsaturated cyclic or acyclic hydrocarbon group. Of the composition containing (a) as a main component, the surface of the fine powder treated with a silane-based organic compound is contained, and the color toner has a weight average particle diameter of 3 to 7 μm. The color toner contains more than 40% by number of toner having a particle size of 5.04 μm or less, 10 to 70% by number of toner having a particle size of 4 μm or less, and a toner having a particle size of 8 μm or more. 2-20% by volume, 10.0
6% by volume or less of a toner having a particle size of 8 μm or more is contained, the carrier has a 50% average particle size of 20 to 45 μm, and carrier particles smaller than 21 μm are contained in an amount of 0.1 to 10% of all carriers. A two-component color developer comprising 20% by volume and 3 to 40% by volume of carrier particles larger than 43 μm based on all carriers.