JPH08184988A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE: To obtain an electrostatic charge image developing toner having a clear picture characteristic free of fog and excellent in durable stability by specifying the ratio of the maximum X-ray intensity level to minimum X-ray intensity level by X-ray diffraction analysis in an organically-treated alumina powder. CONSTITUTION: This electrostatic charge image developing toner has at least a toner grain and an organically-treated alumina powder. In X-ray diffraction analysis of the alumina powder, the ratio of the maximum X-ray intensity level Ia-max when 2θ is in the range from 20B to 70deg to the minimum X-ray intensity level Ia-max . is found to be <6. Since such an alumina powder does not take the definite form of crystal, the association of the alumina grains is hardly recognized, and the aggregation degree of the grains is extremely low. Consequently, when the grains are mechanically dispersed to a primary grain diameter in the soln., the grains are disentangled with a low energy and the surface activity is high, and hence the org. treatment proceeds uniformly.

Description

Detailed Description of the Invention

[0001]

The present invention relates to electrophotography, electrostatic recording,
The present invention relates to a dry type electrostatic image developing toner for developing an electrostatic 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, generally, colorant-containing resin particles obtained by mixing and dispersing a colorant in a thermoplastic resin and then pulverizing the mixture are used. The most common thermoplastic resin is polystyrene resin, but polyester resin, epoxy resin, acrylic resin,
Urethane resins and the like 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, iron powder, and ferrite 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.

It has been proposed to add an external additive to the toner particles to stabilize the triboelectric chargeability of the toner. For example, the use of hydrophobized alumina is disclosed in JP-A-61-275862 and JP-A-61-275863.
It has been proposed in the Japanese publication. These are alumina coated with amino-modified silicone oil, and the agglomeration of alumina particles after treatment is unavoidable, and it is difficult to impart high fluidity to the toner.

The use of hydrophobized alumina is disclosed in Japanese Patent Laid-Open Nos. 62-8164 and 62-12.
No. 9860, No. 62-129866, No. 62-209538, No. 4-34516.
No. 8 and Japanese Patent Laid-Open No. 4-345169. However, these do not mention at all about the surface activity and the crystal structure of the alumina particles for uniform hydrophobic treatment, and these are mainly used only for stabilizing the charge, Highly fluidity is imparted to the toner when used in combination with silica or the like, which is a point to be improved in terms of imparting high fluidity by the alumina itself.

Further, in JP-A-2-251970, alumina is also described as an external lubricant which is surface-treated with a coupling agent, but it is particularly high temperature and high humidity when treated with ordinary alumina. Problems tend to occur in the stabilization of the charging below, and it was not always satisfactory in terms of stabilization of the charging.

Further, by using a hydrophobized alumina fine powder, for the purpose of securing fluidity and stabilizing charging, and particularly preventing overcharging under low temperature and low humidity, JP-A-4-280254 and JP-A-4-280254. No. 280255, JP-A-4-345.
Japanese Patent No. 169 proposes an alumina fine powder having a hydrophobicity of 40% or more. Although it is certainly effective in stabilizing the charge, it is still required to be improved in terms of imparting fluidity as compared with fine powders having a high BET specific surface area such as silica, and uniform treatment has been performed. Further, there has been a strong demand for a hydrophobized alumina fine powder which has few aggregated particles and maintains a high BET specific surface area.

Further, in Japanese Patent Laid-Open No. 3-191363,
Although there is a description of a toner containing a hydrophobic γ-crystal alumina polishing substance, this is to show the polishing effect of alumina, which has been conventionally shown, uniformly and effectively when a photoreceptor of amorphous silicon is used. It has been studied, and has properties different from those of the alumina fine powder which simultaneously satisfies the two functions of imparting fluidity and stabilizing charge.

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, an attempt has been made to achieve high image quality color by making toner particle size fine. However, as the particle size becomes finer, the surface area per unit weight increases, and the toner charge amount 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 substance or carbon black, there is no portion for leaking the charge, and the charge amount generally tends to be large. 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 have been made on the binder resin, and a toner satisfying the above characteristics has been desired. Today, polyester resins are often used as binder resins for colors in the technical field, but toners made of polyester resins are generally susceptible to temperature and / or humidity, and excessively large charge amount under low humidity conditions. However, the problem of insufficient charge amount under high humidity has arisen, and there is an urgent need to develop a color toner having a stable charge amount even in a wide range of environments.

[0028]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner for developing an electrostatic charge image, which solves the above problems.

That is, an object of the present invention is to provide a toner for developing an electrostatic charge image, which has clear image characteristics without fog and is excellent in durability stability.

A further object of the present invention is to provide a toner for developing an electrostatic charge image which is excellent in fluidity, development fidelity and transferability.

A further object of the present invention is to provide an electrostatic charge image developing toner which is not easily affected by environment such as temperature and / or humidity and which has stable triboelectric chargeability.

A further object of the present invention is to provide a toner for developing an electrostatic charge image, which has a good cleaning property and has less filming or contamination on the photoreceptor.

A further object of the present invention is to provide excellent fixability,
It is an object of the present invention to provide a toner for developing an electrostatic charge image having excellent HP transparency.

[0034]

According to the present invention, in an electrostatic charge image developing toner having at least toner particles and organically treated alumina powder, the organically treated alumina powder has a 2θ of 20 in X-ray diffraction analysis. Through 70 deg
Of the maximum X-ray intensity level I _a-max and the minimum X-ray intensity level I _a-min (I _a-max / I _a-min ) of less than 6 For toner.

As a result of intensive investigations by the present inventors for the purpose of stabilizing charge and securing high fluidity of the toner for developing an electrostatic image, organically treated alumina powder having low crystallinity is effective as an external additive. I found that there is.

The organically treated alumina powder used in the present invention has a range of 20 ≦ 2θ ≦ calculated from X-ray diffraction data.
The ratio of the maximum X-ray intensity level I _a-max to the minimum X-ray intensity level I _{a-min at} 70 (deg) (I _a-max /
The major feature is that I _a-min ) is less than 6 and does not take a clear crystal form (see FIGS. 3 and 4 of the accompanying drawings).

Generally, in a method for producing a crystalline alumina powder such as α-alumina powder, a sintering process at a high temperature or a hydrolysis or thermal decomposition step is essential, so that coalescence at the grain interface during the crystal growth process is required. In addition, particle growth occurs and alumina fine powder having a large particle size is generated. Further, as shown in FIG. 5, the α-alumina powder has a ratio I _a-max /
The value of I _a-min is as large as about 67.

Further, with the alumina fine powder produced by the high temperature (flame) hydrolysis method of anhydrous aluminum chloride, crystal growth is slightly suppressed, and it is possible to produce an alumina powder having a relatively small primary particle diameter. Since the treatment is carried out at a high temperature, the ratio I _a-max / I _a-min shows a large value of 6 or more. In this case, the cohesive force between the alumina particles becomes high and the surface activity is high. Since it is low, it is disadvantageous for treatment with an organic treatment agent (hydrophobic treatment agent).

On the other hand, since the alumina powder used in the present invention does not have a definite crystal form, that is, the crystal growth is suppressed, the coalescence between the alumina particles and the alumina particles is extremely small, The degree of aggregation is also extremely weak. Therefore, when the alumina particles are mechanically dispersed in a solution so as to have a primary particle size, the alumina particles are easily disintegrated by low energy dispersion and the surface activity is high, so that the organic treatment uniformly proceeds.

Therefore, it becomes possible to impart good fluidity to the toner particles, and the fine line reproducibility of the original document,
A high-quality toner image excellent in highlight reproducibility can be provided.

In addition, in comparison with ordinary alumina powder,
There are many active Al-OH groups on the surface of the powder, and therefore the surface activity is high, which is advantageous for the reaction with the organic treating agent, and the surface treatment can be performed uniformly. Moreover, when it is dispersed in the toner particles, it shows good dispersibility, and when it is adhered to the surface of the toner particles, the adhesive force between the binder resin and the organically treated alumina powder is high, and the toner particles have a high durability from the surface of the toner particles due to durability. The organically treated alumina powder is not detached to contaminate the surface of the carrier particles or the photosensitive drum, and the initial characteristics can be maintained for a long time even in long-term durability.

The organically treated alumina fine powder used in the present invention contains a large amount of structured water, and the amount thereof is much larger than that of α-type alumina. Therefore, it also functions as a powder having a kind of leak point and suppresses an excessive charge amount of the toner particles. In particular, the effect is exhibited at low temperature and low humidity, and the effect is remarkable when a polyester resin is used as the binder resin. Further, the effect is remarkable when the toner particles are reduced in size.

Further, the organically treated alumina fine powder used in the present invention has a small primary particle size and is capable of reducing secondary agglomerates to a very small extent, so that it can be used as a color toner for forming a full color image. When it is used as an additive, it can be externally added to toner particles uniformly, has excellent light transmittance in visible light, and a clear OHP image can be obtained. this is,
This is something that cannot be achieved with conventional alumina fine powder.

The organically treated alumina powder used in the present invention will be described in more detail.

The ratio I of the maximum X-ray intensity level I _a-max and the minimum X-ray intensity level I _a-min calculated from the X-ray diffraction data.
_In addition to the value of _a-max / I _a-min being less than 6, the maximum X-ray intensity level I _b-max and the minimum X-ray intensity level within the measurement range of 30 ≦ 2θ ≦ 40 (deg) I
It is more preferable value of the ratio _{I b-max / I b-} min of the _b-min is less than 2.

That is, even if alumina satisfying I _max / I _min <6, if it is hydrolyzed or pyrolyzed at a higher temperature, some crystallization proceeds, and 30 ≦ 2θ ≦ in X-ray diffraction data. When a new peak appears within the range of 40 (deg), the cohesive force between the alumina particles tends to increase. It is considered that this is because a part of the alumina has begun to become α, and when this alumina powder is mixed with toner particles and applied, the fluidity tends to decrease.

Here, the reason why the measurement range of 30 ≦ 2θ ≦ 40 (deg) is selected is that when the alumina particles are gradually treated at a high temperature, some peaks appear within this range, and the crystal is further crystallized. As the chemical conversion progresses, the peak becomes sharper, and in addition, the value of the ratio I _b-max / I _b-min gradually increases, and in the end, it is peculiar to alumina having a clear crystal structure called α-alumina. It changes so as to show a diffraction pattern.

Therefore, in order to obtain an alumina powder having a small primary particle size and a low cohesiveness, I _b-max /
Alumina powder having an I _b-min value of less than 2 is preferably used as the base of the organically treated alumina.

In particular, the alumina powder used as the base of the organically treated alumina powder is preferably an alumina fine powder obtained by thermally decomposing aluminum ammonium carbonate hydroxide within a temperature range of 300 to 1200 ° C.

Aluminum ammonium carbonate hydroxide represented by the general formula NH ₄ AlO (OH) HCO ₃ or NH ₄ AlCO ₃ (OH) ₂ is fired, for example, in an oxygen atmosphere within a temperature range of 300 to 1000 ° C. to obtain fine alumina powder. It is preferable to obtain a body. That is, the following formula 2NH ₄ AlCO ₃ (OH) ₂ → Al ₂ O ₃ + 2NH ₃ + 3H
_The alumina fine powder obtained after the chemical reaction represented by ₂ O + ₂ CO ₂ is preferred. Here, the temperature in the range of 300 to 1200 ° C. is selected as the firing temperature, because the target activity of the present invention is high and alumina having a high BET specific surface area can be obtained in a high yield.

If the firing temperature is higher than 1200 ° C., the proportion of α-alumina in the alumina fine powder produced will increase sharply. Naturally, the powder grows structurally, the primary particle size increases,
The specific surface area indicated by the BET value decreases. In addition, the degree of coagulation between the powders increases, and a large amount of energy is required to disperse the drug substance in the treatment process. In such a state of powder, no matter how much the treatment process is optimized, there are few aggregated particles. Fine powder is hard to be generated.

On the other hand, when the calcination temperature is lower than 300 ° C., complete or sufficient thermal decomposition of aluminum ammonium carbonate hydroxide is not carried out, and gases such as H ₂ O, NH ₃ and CO ₂ are contained in the produced alumina. The components may remain. In this case, even if a uniform hydrophobic treatment is attempted, the degree of hydrophobicity cannot be increased to a desired level, and even if the apparent degree of hydrophobicity is increased, stable chargeability cannot be obtained and durability is inevitable. Various problems will occur.

The heat treatment temperature of aluminum ammonium carbonate hydroxide is more preferably 30.
0 to 1100 ° C, more preferably 350 to 1000
C., most preferably 400 to 500.degree.

The alumina powder having _a ratio I _a-max / I _a-min value of less than 6 is preferably treated with a silane-based organic compound, and in particular, the silane-based coupling agent is hydrolyzed in a solution. However, it is preferable to perform surface treatment to make it hydrophobic.

The organically treated alumina powder preferably has a methanol hydrophobicity of 30 to 90% from the viewpoint of environmental stability.

While the silica fine particles themselves have a strong negative chargeability, the alumina powder has a substantially neutral chargeability, and can be controlled to a desired charge level depending on the degree of hydrophobic treatment. caused by. Conventionally, it has been proposed to add a toner hydrophobic alumina powder, but the alumina powder originally has a much lower surface activity than silica, so that the hydrophobicization is not always sufficiently performed. Therefore, when a large amount of treatment agent or the like or a high-viscosity treatment agent is used, the degree of hydrophobicity is surely increased, but particles are coalesced with each other and the BET specific surface area is reduced, resulting in fluidity. The stabilization of charging and the imparting of fluidity are not necessarily achieved at the same time, for example, the imparting ability decreases.

The hydrophobizing agent 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, it is preferable to use a silane-based organic compound such as alkylalkoxysilane, siloxane, silane, or silicone oil, which does not decompose thermally at the reaction treatment temperature.

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. Is good.

R _m SiY _n [In the formula, 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.
Further, when a is larger than 13, the hydrophobicity is sufficient, but the coalescence of the fine powders is increased and the fluidity imparting ability tends to be lowered.

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

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

The treatment amount is 1 to 50 parts by weight, preferably 3 to 45 parts by weight, based on 100 parts by weight of the alumina fine powder, and the degree of hydrophobicity is 30 to 90%, preferably 40 to 80.
You can set it to%.

That is, if the degree of hydrophobicity is less than 30%, the amount of charge is greatly reduced by leaving it in high humidity for a long period of time, and a mechanism for accelerating the charge on the hardware side is required, which makes the device complicated. When the degree of hydrophobicity exceeds 90%,
It becomes difficult to control the charge of the alumina fine powder itself,
As a result, the toner is likely to be charged up under low humidity, which is not preferable.

Further, the treated alumina fine powder in the present invention preferably has an average particle size of 0.0 from the viewpoint of imparting fluidity.
02-0.1 μm, more preferably 0.005-0.0
5 μm is good.

When the average particle diameter is larger than 0.1 μm, the fluidity is lowered, the toner is apt to be non-uniformly charged, and as a result, the toner is liable to be scattered or fogged, which makes it difficult to form a high quality image. Become. The average particle size is 0.00
If it is less than 2 μm, the treated alumina 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 lowered. This tendency is more remarkable when applied to a sharp melt color toner. On the other hand, when it is less than 0.002 μm, the activity of the alumina particles is inevitably high, particles tend to aggregate, and it becomes difficult to obtain the desired high fluidity. In addition,
The particle size of the treated alumina fine powder in the present invention was measured by a transmission electron microscope.

In the present invention, the method for treating the fine alumina powder is effective by hydrolyzing the coupling agent while mechanically dispersing the fine alumina powder in the solution so as to have a primary particle size. However, it is not particularly limited.

The content of the treated alumina fine powder suitable for the present invention is 0.5 to 5 parts by weight, preferably 0.6 to 3 parts by weight, more preferably 0.
7 to 2.5 parts by weight.

If the amount is less than 0.5 part by weight, the fluidity of the toner tends to be lowered, and conversely, if the amount is more than 5 parts by weight, the toner tends to be separated from the toner. The treated alumina powder that has come off is
It is not preferable because the carrier surface is easily contaminated and the charge imparting ability of the carrier itself is lowered, and the released organically treated alumina powder easily flies onto the photoreceptor surface during development,
It is also likely to cause poor cleaning. Further, when it is used as a color toner, if a large amount of organically treated alumina powder is contained, the projected image of OHP will be sharpened and a clear toner will not be obtained.

Further, in the present invention, the BET specific surface area of the organically treated alumina powder is preferably 130 m ² / g or more, more preferably 150 m ² / g or more.

When the BET specific surface area is smaller than 130 m ² / g, even if the structure shows that the crystal growth is suppressed, the alumina particles grow and become large, or the alumina that has crystallized to α-alumina is less than one. Since the parts are mixed, it is difficult to obtain high fluidity. In addition, although the BET specific surface area value was very high in the untreated stage before the treatment, the BET was greatly increased in the hydrophobic treatment step.
The specific surface area value was also decreased, and as a result, the BET specific surface area was smaller than 130 m ² / g,
In the case where the alumina particles did not disperse uniformly in the solution and reacted with the treating agent while remaining in the form of agglomerates, or the treating agent itself self-condensed and became a part of oil, resulting in alumina particles or alumina coagulation. A case or the like that has adhered to the surface of the aggregate corresponds to this, and it is difficult to obtain the desired uniform surface-treated alumina fine powder.

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

The inventors of the present invention have diligently studied the image density, highlight reproducibility and fine line reproducibility of the developer.
When the weight average particle diameter of the toner is 3 to 7 μm, it is possible to faithfully develop the latent image on the photosensitive member, and the amount of toner particles having a particle diameter of 4 μm or less improves highlight reproducibility. It has been found to greatly contribute to.

That is, the weight average particle diameter of the toner is 7 μm.
When larger, it basically means that there are few toner particles that can contribute to high image quality, and it is easy to obtain a high image density, and there are advantages such as excellent toner fluidity, but fine particles on the drum. It is difficult for the toner particles to adhere to the latent image faithfully, 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, especially 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.

Further, when the weight average particle diameter of the toner is smaller than 3 μm, it is difficult to smoothly charge the toner by contact with the carrier, the number of toner particles which cannot be sufficiently charged increases, and scattering to the non-image area, that is, fog. Will be noticeable. In order to deal with this, it is conceivable to reduce the diameter of the carrier in order to increase the specific surface area of the carrier, but the weight average particle diameter is 3
With toner of less than μm, toner self-aggregation easily occurs,
Uniform mixing with the carrier is not achieved in a short time, and fog toner tends to occur inevitably during continuous toner replenishment durability.

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

In the toner of the present invention, the toner particles having a particle diameter of 4 μm or less are preferably 10 to 70% by number, and more preferably 15 to 60% by number of the total number of toner 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 that are essential components for high image quality. As a result, the effective toner particle component decreases, the balance of the particle size distribution of the toner deteriorates, and the image quality tends to decrease gradually.

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

Further, toner particles having a particle size of 8 μm or more are 2 to
It is preferably 20% by volume, preferably 3.0 to 1
8.0 volume% is good. 2 toner particles with a particle size of 8 μm or more
When the content is more than 0% by volume, the image quality is deteriorated, and more than necessary development, that is, excessive toner overload occurs, and the toner consumption amount tends to increase. On the other hand, if the amount of toner particles having a particle diameter of 8 μm or more is less than 2% by volume, the fluidity of the toner may be reduced and the image quality may be reduced.

Further, in order to further improve the effect of the present invention, the toner particles having a particle diameter of 5.04 μm or less are 40 to 90% by number, preferably the toner particles having a particle size of 5.04 μm or less are preferably used for the purpose of improving the chargeability and fluidity of the toner. , 40% by number to 80% by number, and toner particles having a particle size of 10.08 μm or more
6% by volume, and more preferably 0 to 4% by volume.

Particularly, in order to make full use of the toner having a fine particle diameter, improvement of fluidity and stabilization of charging are major points, and a good image cannot be expected even if either of them is lacking.

Therefore, in order to maximize the characteristics of the toner having the particle size distribution as described above and to achieve high resolution and high gradation, the surface-treated alumina fine powder having a large fluidity imparting ability as described above is used. It is important to use them together, and a good image can be obtained by combining them.

Further, although the charge per toner particle becomes smaller and the toner tends to scatter due to the finer toner particles, the alumina fine powder of the present invention has a high charge imparting ability and improves the fluidity and the charge. Both stabilization can be achieved.

Further, in the present invention, the cohesion degree of the toner is preferably 2 to 25% (preferably 2 to 20%, more preferably 2 to 15%).

If the degree of cohesion exceeds 25%, problems such as deterioration of toner transportability from the toner hopper to the developing device, poor mixing of toner and carrier, and further defective charging of toner are likely to occur. Therefore, make the toner finer,
Even if the coloring power of the toner is optimized, it is difficult to obtain high-quality image quality.

It is general to add silica fine powder having a large BET specific surface area for the purpose of reducing the cohesion degree of the toner. However, when silica fine powder is added, the environmental characteristics of the toner are liable to be deteriorated, and the silica fine powder is highly humidified. Of the toner tends to decrease, and the charge amount of the toner tends to increase under low humidity. Further, since the silica fine powder itself has a large negative charging property, when used as an external additive, electrostatic cohesive force between toner particles is increased, and it is difficult to obtain a desired toner having high fluidity.

As the binder substance used for the colorant-containing resin particles, various resins conventionally known as binder resins for electrophotographic toners are used.

For example, polystyrene, styrene-based copolymers such as styrene-butadiene copolymer, styrene-acrylic 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.

Of these resins, the effect of the present invention is remarkable when a polyester resin having a particularly high negative charging ability 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 tend to become excessively charged, but when alumina fine powder is used, adverse effects are improved and excellent toners are obtained. .

In particular, the following equation

[0094]

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 (for example, chromium complex, aluminum 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 preferable 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 other additives within the range not impairing the characteristics of the toner. 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, Ester wax).

To prepare the toner particles according to the present invention, a thermoplastic resin, if necessary, is sufficiently mixed with a pigment or dye as a colorant, a charge control agent and other additives by a mixer such as a ball mill. From heating roll, kneader,
Using a heat kneader such as an extruder, melt, knead and knead the meat to make the resins compatible with each other, and disperse or dissolve the pigment or dye, cool and solidify, pulverize and strictly classify. The toner particles according to the invention can be obtained.

When the toner of the present invention is used as a two-component developer, examples of carriers used include surface-oxidized or non-oxidized iron, nickel, copper, zinc, cobalt,
Metals such as manganese, chromium, rare earths and their magnetic alloys or magnetic oxides and magnetic ferrites can be used.

When the carrier is a carrier in which the carrier core is coated with a coating material, the method of coating the surface of the carrier core with a resin or the like is as follows: the coating material such as a resin is dissolved or suspended in a solvent and applied. Any conventionally known method such as a method of adhering to the above, a method of simply mixing with powder, or the like can be applied.

The substance adhered to the surface of the carrier core varies depending on the toner material, and examples thereof include polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, metal complex of tert-butyl salicylic acid, and styrene. Resin, acrylic resin, polyamide, polyvinyl butyral, nigrosine, amino acrylate resin,
It is suitable to use a basic dye and its lake, fine silica powder, fine alumina powder, etc., alone or in combination, but it is not necessarily limited thereto.

The treatment amount of the above compounds may be appropriately determined, but in general, the total amount is preferably 0.1 to 30% by weight (preferably 0.5 to 20% by weight) based on the carrier.

The average particle size of the carrier is 10 to 100 μm,
It is preferably 20 to 70 μm.

A particularly preferred embodiment is magnetic ferrite, the surface of which is a combination of resins such as silicone resin or fluorine resin and styrene resin, for example, polyvinylidene fluoride and styrene-methyl methacrylate resin; polytetrafluoroethylene. 90:10 to 20: styrene-methyl methacrylate resin, fluorine-based copolymer and styrene-based copolymer; silicone-based resin, etc.
80, preferably 70:30 to 30:70 in a mixture of 0.01 to 5% by weight, preferably 0.
1 to 1 wt% coating, 250 mesh pass, 40
An example is a coated magnetic ferrite carrier having the above-mentioned average particle size of 0 mesh-on carrier particles of 70% by weight or more. Examples of the fluorine-based copolymer include vinylidene fluoride tetrafluoroethylene copolymer (copolymerization weight ratio of 10:90 to 90:10), and examples of the styrene-based copolymer include styrene-2-ethylhexyl acrylate (copolymer). Polymerization weight ratio 20:80 to 80:20), styrene-2-ethylhexyl acrylate-methyl methacrylate (copolymerization weight ratio 20 to 60: 5 to 30:10 to 5)
0) can be mentioned.

When the above-mentioned coated magnetic ferrite carrier has a sharp particle size distribution, it is possible to obtain a preferable triboelectrification property for the toner of the present invention and to improve the electrophotographic characteristics.

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 the toner concentration in the developer. More preferably 4% to 10% by weight
A good result is usually obtained. If the toner density is less than 2% by weight, the image density tends to be low, and
If it exceeds, fogging and scattering in the machine are likely to occur, and the useful life of the developer tends to be shortened.

Next, an example of a developing device for developing a non-magnetic one-component toner using the toner of the present invention will be described.
It is not necessarily limited to this. FIG. 1 shows an apparatus for developing an electrostatic image formed on a latent image carrier. In the latent image carrier 1, the latent image is formed by electrophotographic process means or electrostatic recording means (not shown). The developer carrying member 2 is composed of a non-magnetic sleeve made of aluminum, stainless steel or the like. The non-magnetic one-component color toner is stored in the hopper 3 and is supplied onto the developer carrier 2 by the supply roller 4. The supply roller 4 also removes the toner on the developer carrying member 2 after development. The toner supplied onto the developer carrier 2 is uniformly and thinly applied by the developer applying blade 5. The contact pressure between the developer coating blade 5 and the developer carrying member 2 is effectively 3 to 250 g / cm, preferably 10 to 120 g / cm as the linear pressure in the sleeve generatrix direction. When the contact pressure is less than 3 g / cm, it becomes difficult to apply the toner uniformly, and the charge amount distribution of the toner becomes broad, which easily causes fog and scattering. When the contact pressure exceeds 250 g / cm, a large pressure is applied to the toner, which is not preferable because the toner particles are easily aggregated or crushed. By adjusting the contact pressure to 3 to 250 g / cm, it becomes possible to satisfactorily loosen the agglomeration of the toner having a small particle diameter, and it is possible to instantly increase the triboelectric charge amount of the toner. As the developer coating blade 5, it is preferable to use a material of triboelectric charging series suitable for charging the toner to a desired polarity.

In the present invention, silicone rubber, urethane rubber, styrene-butadiene rubber and the like are preferable.
The use of conductive rubber is preferable because it can prevent the toner from being triboelectrically charged excessively. If necessary, the surface of the blade 5 may be coated. In particular, when used as a negative toner, it is preferable to coat a positively chargeable resin such as polyamide resin.

In a system in which a thin layer of toner is coated on the developer carrying member 2 with the blade 5, the thickness of the toner layer on the developer carrying member 2 is adjusted to obtain a sufficient image density. It is preferable that the length is smaller than the opposing gap length between the latent image carrier 1 and the latent image carrier 1 and an alternating electric field is applied to this gap. By applying a developing bias in which a DC electric field is superimposed on the alternating electric field or the alternating electric field between the developer carrying member 2 and the latent image holding member 1 by the bias power source 6 shown in FIG. The toner on the body 1 can be easily moved, and a high quality image can be obtained.

An image forming apparatus for satisfactorily carrying out the full-color image forming method using the toner of the present invention will be described with reference to FIG.

The color electrophotographic apparatus shown in FIG. 2 includes a transfer material conveying system 1 provided from the right side of the apparatus main body 1 (right side of FIG. 1) to a substantially central portion of the apparatus main body, and the apparatus main body 1.
A latent image forming section II provided in the approximate center of the image forming section II in the vicinity of the transfer drum 315 forming the transfer material conveying system I.
And a developing means (that is, a rotary developing device) III arranged in proximity to the latent image forming section II.

The transfer material carrying system I has the following structure. An opening is formed in the right wall (right side in FIG. 2) of the apparatus main body 1, and transfer material supply trays 302 and 303 which are detachable are arranged in the opening so as to partially project outside the machine. Paper feed rollers 304 and 305 are arranged substantially directly above the trays 302 and 303, and these paper feed rollers 304 and 305 and a transfer drum 305 disposed on the left side and rotatable in the direction of arrow A are arranged. To work together,
Paper feed roller 306 and paper feed guides 307 and 308
Is provided. In the vicinity of the outer peripheral surface of the transfer drum 315, the contact roller 309, the gripper 310, and the transfer material separating charger 31 from the upstream side to the upstream side in the rotation direction.
1. The separation claw 312 is sequentially arranged.

A transfer charger 313 and a transfer material separating charger 314 are provided on the inner peripheral side of the transfer drum 315. A transfer sheet (not shown) made of a polymer such as polyvinylidene fluoride is attached to a portion of the transfer drum 315 around which the transfer material is wound, and the transfer material is electrostatically attached on the transfer sheet. It is attached closely to. A conveyor belt means 316 is provided on the upper right side of the transfer drum 315 in proximity to the separation claw 312, and a fixing device 318 is provided at the end (right side) of the conveyor belt means 316 in the transfer material conveying direction. There is. A discharge tray 317 that extends to the outside of the apparatus main body 301 and is detachable from the apparatus main body 301 is disposed further downstream than the fixing device 318 in the transport direction.

Next, the structure of the latent image forming section II will be described. A photosensitive drum (for example, an OPC photosensitive drum) 319, which is a latent image carrier rotatably in the direction of the arrow in FIG. 2, is arranged with its outer peripheral surface in contact with the outer peripheral surface of the transfer drum 315. Above the photosensitive drum 319 and in the vicinity of the outer peripheral surface thereof, a charge removing charger 320 and a cleaning unit 321 are provided from the upstream side to the downstream side in the rotation direction of the photosensitive drum 319.
And a primary charger 323 are sequentially arranged, and an image exposure unit 324 such as a laser beam scanner for forming an electrostatic latent image on the outer peripheral surface of the photosensitive drum 319 and an image exposure reflection unit 325 such as a mirror. It is arranged.

The structure of the rotary developing device III is as follows. A rotatable housing (hereinafter referred to as “rotating body”) 3 is provided at a position facing the outer peripheral surface of the photosensitive drum 319.
26, four types of developing devices are mounted at four positions in the circumferential direction in the rotating body 326.
The electrostatic latent image formed on the outer peripheral surface of is visualized (that is, developed). The above four types of developing devices
Each has a yellow developing device 327Y, a magenta developing device 327M, a cyan developing device 327C, and a black developing device 327BK.

The sequence of the entire image forming apparatus having the above configuration will be described by taking the case of the full color mode as an example. When the photosensitive drum 319 described above rotates in the direction of the arrow in FIG. 2, the photosensitive member on the photosensitive drum 319 is charged by the primary charger 323. In the apparatus of FIG. 2, the operating speed of each part (hereinafter referred to as process speed) is 100 mm / sec or more (for example, 130 to 250 mm).
/ Sec). When the photosensitive drum 319 is charged by the primary charger 323, image exposure is performed by the laser light E modulated by the yellow image signal of the original 328, and an electrostatic latent image is formed on the photosensitive drum 319.
By the rotation of the rotating body 326, the electrostatic latent image is developed by the yellow developing device 327Y which is fixed at the developing position in advance, and a yellow toner image is formed.

Paper feed guide 307, paper feed roller 306,
The transfer material conveyed through the paper feed guide 308 is
It is held by the gripper 310 at a predetermined timing,
It is electrostatically wound around the transfer drum 315 by the contact roller 309 and the electrode facing the contact roller 309. The transfer drum 315 is the photosensitive drum 319.
The yellow toner image formed by the yellow developing device 327Y is rotating in the direction of the arrow in FIG.
The outer peripheral surface of the photosensitive drum 319 and the transfer drum 315
The image is transferred onto the transfer material by the transfer charger 313 at the portion in contact with the outer peripheral surface of. The transfer drum 315 continues to rotate and the next color (magenta in FIG. 2)
Prepare for the transfer.

The photosensitive drum 319 is the charger 3 for static elimination.
After the charge is removed by 20 and the cleaning means 321 by the cleaning blade cleans it, it is charged again by the primary charger 323, and image exposure is performed by the next magenta image signal to form an electrostatic latent image. The rotary developing device rotates while an electrostatic latent image is formed on the photosensitive drum 319 by imagewise exposure with a magenta image signal to position the magenta developing device 327M at the above-described predetermined developing position and to perform a predetermined operation. Develop with magenta toner. Subsequently, the above-described processes are performed for cyan and black, respectively, and when the transfer of the four color toner images is completed, the four color developed images formed on the transfer material are charged by the chargers 322 and 314, respectively. The gripping of the transfer material by the gripper 310 is released, the transfer material is separated from the transfer drum 315 by the separating claw 312, and the transfer belt 316 fixes the fixing material to the fixing device 3.
Then, it is sent to 18 and fixed by heat and pressure to complete a series of full-color printing sequence, and a required full-color printing image is formed on one surface of the transfer material.

At this time, the fixing operation speed of the fixing device 318 is the process speed of the main body (for example, 160 mm / s).
ec) is performed later (for example, 90 mm / sec). This is because when the unfixed image in which two to four layers of toner are laminated is melt-mixed, it is necessary to give a sufficient heating amount to the toner. The amount is increasing.

The method of measuring 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)
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.

Cohesion Degree Measurement The cohesion degree is used as one means for measuring the flow characteristics of a sample (a toner having an external additive, etc.). The larger the value of this cohesion degree, the poorer the fluidity of the sample. .

As a measuring device, a powder tester (manufactured by Hosokawa Micron Co.) having a digital vibrometer (Digivibro MODEL 1332) is used.

As a measuring method, 200 mesh, 100 mesh, and 60 mesh sieves were placed on the vibrating table in the order of narrow openings, that is, in order of 200 mesh, 100 mesh, and 60 mesh sieves so that the 60 mesh sieve was at the top. Set on top of each other.

5 g of an accurately weighed sample was added to the set 60 mesh sieve, and the input voltage to the shaking table was set to 2
The value of the displacement of the digital vibrometer is set to 0.130, and the amplitude of the vibration table at that time is 60 to 90 μ.
Adjust so that it falls within the range of m (Rheostat scale about 2.
5), shake for about 15 seconds. Then, the weight of the sample remaining on each sieve is measured to calculate the aggregation degree based on the following formula.

[0129]

[Equation 1]

The sample used was left in an environment of temperature 23 ° C. and humidity 60% RH for about 12 hours, and the measurement environment was temperature 23 ° C. and humidity 60% RH.

Method for Measuring Average Particle Size of Alumina Fine Powder The primary particle size was determined by observing the alumina fine powder with a transmission electron microscope and measuring 100 particle sizes in the visual field to obtain the average particle size. The dispersed particle size is observed by a scanning electron microscope, 100 alumina fine powders in the visual field are qualitatively determined by XMA, and the particle size is measured to obtain the average particle size.

Measurement of Hydrophobicity The methanol titration test is an experimental test for confirming the hydrophobization degree of alumina fine powder having a hydrophobized surface.

The "methanol titration test" defined in this specification for evaluating the hydrophobicity of the treated alumina fine powder is performed as follows. Tested alumina powder 0.2g
Is added to 50 ml of water in the container. Methanol is titrated from the burette until the total amount of alumina fines is wet. At this time, the solution in the container is constantly stirred with a magnetic stirrer. The end point is observed by suspending all of the fine alumina powder in the liquid, and the degree of hydrophobicity is expressed as the percentage of methanol in the liquid mixture of methanol and water when the end point is reached.

Measuring Method of BET Specific Surface Area The BET of alumina fine powder is actually measured as follows.

BET specific surface area is manufactured by Yuasa Ionics Co., Ltd., fully automatic gas adsorption measuring device: Autosorb 1
Is used and nitrogen gas is used as an adsorption gas, and the BET multipoint method is used. The sample was pretreated at a temperature of 5
Degas for 10 hours at 0 ° C.

Crystal Structure Analysis Method In the present invention, the crystal structure analysis of the alumina fine powder is performed as follows.

X-ray crystal structure analysis was carried out using the characteristic X-ray K of Cu.
It is determined by an X-ray diffraction spectrum using α rays as a radiation source. As a measuring machine, for example, a powerful full-automatic X-ray diffractometer MXP ¹⁸ (manufactured by Mac Science Co.) can be used.

When the alumina has a well-defined crystal structure,
That is, in the case of α type alumina, 2θ is 20 to 20.
A sharp peak is observed in the range of 70 deg. α
-An example of the X-ray diffraction pattern of alumina is shown in FIG. An example of the X-ray diffraction pattern of amorphous alumina is shown in FIG. 4, and an example of the X-ray diffraction pattern of γ-alumina is shown in FIG.

[0139]

EXAMPLES Examples of the present invention will be described below.

Synthesis Example 1 of Organically Treated Alumina Fine Powder To a 2M ammonium bicarbonate solution, a 0.2M ammonium banban solution was added dropwise while maintaining the liquid temperature at 35 ° C., and the mixture was reacted with stirring to generate and age it. NH ₄
The AlCO ₃ (OH) ₂ crystal is filtered and dried, then at about 650 ° C.
Was heat-treated with to produce fine alumina powder. No clear peak was observed in the X-ray diffraction data of this fine powder, and the ratio I
The value of _a-max / I _a-min was 3.16.

Next, the above alumina fine powder is uniformly dispersed in toluene, and isobutyltrimethoxysilane, which is a silane coupling agent, is added to the alumina fine powder 10.
Hydrolysis reaction was carried out by dropping and mixing so that the solid content would be 30 parts by weight with respect to 0 parts by weight so that the particles would not coalesce.
Then, after filtering and drying, it was baked at 180 ° C. for 2 hours and then sufficiently crushed to obtain the desired surface-hydrophobicized alumina fine powder 1. This treated alumina fine powder has a primary particle diameter of 0.005 μm and a BET specific surface area of 27.
It was 0 m ² / g and the hydrophobicity of methanol was 63%.

Comparative Synthetic Example 1 of Organically Treated Alumina Fine Powder 1 AlCl ₃ was treated in a gas phase at a relatively high temperature to be sintered, and a ratio I _a-max / I _a-min of γ having a value of 6.12. After obtaining a type of hydrophilic alumina fine powder, the surface was subjected to a hydrophobic treatment in the same manner as in Synthesis Example 1 to obtain a comparatively treated alumina fine powder 1.

Comparative Synthesis Example 2 of Organically Treated Alumina Fine Powder The NH ₄ AlCO ₃ (OH) ₂ crystal used in Synthesis Example 1 was
Firing was performed at about 1260 ° C. for about 60 minutes to produce α-alumina fine powder. This alumina fine powder showed a sharp and clear peak in X-ray diffraction data, and was confirmed to be α type.

This α-alumina fine powder was treated in the same manner as in Synthesis Example 1 (however, the amount of the treating agent was reduced to 10% by weight) to obtain comparative treated alumina fine powder 2.

Synthesis Example 2 of Organically Treated Alumina Fine Powder The NH ₄ AlCO ₃ (OH) ₂ crystal produced in Synthesis Example 1 was fired at about 950 ° C. to produce an alumina fine powder. The X-ray diffraction data of this alumina fine powder has 2θ = 45 and 67.
A broad peak was observed near (deg), and it had a γ-type crystal morphology.

Next, the above alumina fine powder was uniformly dispersed in toluene, and then normal-butyltrimethoxysilane was added in a solid content of 25 parts with respect to 100 parts by weight of the alumina fine powder.
The mixture was added dropwise to the mixture so that the weight of the mixture would be about 1 part, and the same procedure as in Synthesis Example 1 was performed.
Organically treated alumina fine powder 2 was produced.

Synthesis Example 3 of Organically Treated Alumina Fine Powder Synthesis Example 2 except that normal-butyltrimethoxysilane was increased to 40 parts by weight in solid content in Synthesis Example 2.
Organic treated alumina fine powder 3 was obtained in the same manner as described above.

Synthetic Example 4 of Organically Treated Alumina Fine Powder NH ₄ AlCO produced in substantially the same manner as in Synthetic Example 1.
A crystal of ₃ (OH) ₂ was fired at about 1050 ° C., and then sufficiently crushed to produce an alumina fine powder.

The obtained alumina fine powder was treated in the same manner as in Synthesis Example 1 (however, the amount of the treating agent was reduced to 20 parts by weight) to obtain an organically treated alumina fine powder 4.

Comparative Synthetic Example 3 of Organically Treated Alumina Fine Powder A comparative treated alumina fine powder 3 was obtained in the same manner as in Synthetic Example 4 except that γ-alumina (BET specific surface area 130 m ² / g) was used.

Comparative Synthetic Example 4 of Organically Treated Titanium Fine Powder A rutile-type hydrophilic titanium oxide having a primary particle diameter of about 30 nm which was sintered at a high temperature was treated in the same manner as in Synthetic Example 3 to obtain a comparative treated titanium oxide fine powder. Got 4.

Table 1 shows the physical property values of the above organically treated fine powder.

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

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.
Further, the finely pulverized product obtained was classified to have a weight average particle size of about 5.7.
Resin particles having a colorant of μm were obtained.

100 parts by weight of the colorant-containing resin particles and 1.2 parts by weight of the hydrophobized alumina fine powder 1 of Synthesis Example 1 were mixed with a Henschel mixer to obtain a cyan toner.
This cyan toner had a weight average particle diameter of 5.7 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. Toner cohesion is 12%
Met.

A Cu-Zn-Fe magnetic ferrite carrier having an average particle size of 50 μm was coated with 0.5% by weight of a copolymer of 50% by weight of styrene, 20% by weight of methyl methacrylate and 30% by weight of 2 ethylhexyl acrylate. 95 parts by weight of coated ferrite carrier and 5 parts by weight of cyan toner were mixed to prepare a two-component developer.

Using this two-component developer, the development contrast was set to 300 V with a commercially available plain paper color copying machine (color laser copier 550, manufactured by Canon) and the temperature was set to 2
Image formation was performed at 3 ° C./humidity of 65% RH. The obtained image was subjected to reflection density measurement using a Macbeth RD918 type using an SPI filter (the same applies to the subsequent image density measurement method). The toner image density was as high as 1.62 and was clear without fog. After that, 10,000 more copies were made, but the density fluctuation during that time was as small as 0.08,
Fog and sharpness were similar to those at the beginning. Even under low temperature and low humidity (temperature 20 ° C / humidity 10% RH), when the development contrast was set to 300V and images were printed, the image density was as high as 1.54, which is effective for controlling the charge amount under low humidity. was there.

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

Even under high temperature and high humidity (temperature 30 ° C./humidity 80%
(RH) Similarly, when the development contrast was set to 300 V and image formation was performed, the image density was 1.68, which was very stable and a good image was obtained.

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

Table 2 shows the particle size distribution / aggregation degree of the toner,
The image characteristics are shown in Table 3 (the same applies hereinafter).

Comparative Example 1 Untreated alumina fine powder (I _a-max / I _a-min = 3.1)
6, I _b-max / I _b-min = 1.7, BET specific surface area 360
m ² / g, primary average particle size = 5 nm, methanol hydrophobicity 0%) except that a toner and a two-component type developer were prepared in the same manner as in Example 1 under high temperature and high humidity ( Three
When tested at 0 ° C./80% RH), the image density was higher than that in Example 1 and the image was fogged overall.

Comparative Example 2 Comparative treated fine powder no. A toner and a two-component developer were prepared in the same manner as in Example 1 except that No. 1 was used, and the same test as in Example 1 was carried out.

When the durability was evaluated in a high temperature and high humidity environment, the charge was stable in the initial stage, but the charge amount decreased as the durability progressed, and the toner was scattered inside the machine, and the durability was interrupted.

Comparative Example 3 Comparative Treatment Fine powder No. A toner and a two-component type developer were prepared and evaluated in the same manner as in Example 1 except that 2 was used. The toner agglomeration degree is as high as 56%, and this tendency is due to the comparatively treated fine powder No. Even when the external addition amount of 2 was increased to 2.0 parts by weight and 3.0 parts by weight, the cohesion of the toner did not change so much.

Further, the transparency of transparency was low, and a clear OHP image could not be obtained. A dry toner image was formed even under normal temperature and normal humidity (23 ° C./65% RH).

Example 2 Toner particles having a weight average particle size of about 6 μm were obtained in the same manner as in Example 1, except that the phthalocyanine pigment was replaced with a quinacridone type magenta pigment.

100 parts by weight of the toner particles and the organically treated alumina fine powder No. 1 described in Synthesis Example 2 were used. A toner and a two-component type developer were prepared and evaluated in the same manner as in Example 1 except that 1.5 parts by weight of 2 was used. Toner cohesion is 16
%, Showing excellent fluidity.

In a low temperature and low humidity environment, an image with excellent reproducibility of the halftone portion was obtained. After a long-term durability evaluation, both the image density and the charge amount were stable. No particular problem occurred even in a high temperature and high humidity environment.

Comparative Example 4 Comparative Treatment Alumina Fine Powder No. A toner and a two-component developer were prepared and evaluated in the same manner as in Example 2 except that No. 3 was used. The toner cohesion was as high as 29%, and in a low-temperature and low-humidity environment, a rough image was formed on the whole, and the image density was low at 1.37. This tendency became more and more noticeable as the number of sheets became more durable, so the durability was interrupted. This is considered to be charge-up due to an excessive amount of toner charge.

Example 3 Evaluation was made in the same manner as in Example 2 except that the treated fine powder 7 was used. Durability was performed in a low temperature and low humidity environment and a high temperature and high humidity environment, but no problem occurred. However, as the durability was promoted in a low temperature and low humidity environment, rubbing in the halftone part became noticeable, but it was at a practical level.

Comparative Example 5 Evaluation was carried out in the same manner as in Example 2 except that the treated fine powder 8 was used. The toner cohesion was as high as 32%, and a rough image was not obtained from the beginning of durability.

The amount of the treated fine powder added was 2.0 parts by weight, 2.
Although the highlight reproducibility was improved as the amount was increased to 5 parts by weight, fog under high temperature and high humidity and toner scattering began to stand out, and compatibility with a low temperature and low humidity environment was not achieved.

Comparative Example 6 Evaluation was made in the same manner as in Example 3 except that the treated fine powder 9 was used. From the initial stage of endurance, only images with a rough texture were obtained.

Example 4 Colorant-containing resin particles having a weight average particle diameter of about 8.5 μm were obtained in the same manner as in the toner manufacturing method described in Example 1. 1. 100 parts by weight of the colorant-containing resin particles and 1.
Cyan toner was mixed with 0 parts by weight, and a two-component developer was obtained in substantially the same manner as in Example 1 (however, the toner concentration was 8%).

Using this developer, the durability was evaluated under a low temperature and low humidity environment. The density was as high as 1.63 and was stable, but the highlight reproducibility was slightly lower than in Example 1. However, it was well within the practical range.

[0177]

[Table 1]

[0178]

[Table 2]

[0179]

[Table 3]

[0180]

EFFECTS OF THE INVENTION The toner of the present invention contains an organically treated alumina fine powder having a low crystallinity, and thus has excellent fluidity, stable charging characteristics, and excellent OHP transparency.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing a specific example of a developing device using a non-magnetic one-component toner to which the electrostatic image developing toner of the present invention can be applied.

FIG. 2 is a schematic explanatory diagram showing a specific example of a full-color copying machine to which the electrostatic image developing toner of the present invention can be applied.

FIG. 3 is a diagram showing an X-ray diffraction pattern of alumina.

FIG. 4 is a diagram showing an X-ray diffraction pattern of amorphous alumina.

FIG. 5 is a diagram showing an X-ray diffraction pattern of α-alumina.

[Explanation of symbols]

 1 latent image carrier (photosensitive drum) 2 developer carrier (development sleeve) 3 hopper 4 supply roller 5 developer coating blade 6 power supply

Claims (10)

[Claims] 1. A toner for developing an electrostatic charge image comprising at least toner particles and organically treated alumina powder, wherein the organically treated alumina powder is 2θ in X-ray diffraction analysis.
Of the maximum X-ray intensity level I _a-max and the minimum X-ray intensity level I _a-min in the range of 20 to 70 deg (I
_a-max / I _a-min ) of less than 6, an electrostatic image developing toner. 2. The organically treated alumina powder has a primary particle size of 0.
The toner for developing an electrostatic charge image according to claim 1, which has a particle size of 002 to 0.1 μm. 3. The electrostatic image development according to claim 1 or 2, wherein the organically treated alumina powder has a BET specific surface area by nitrogen gas of 130 m ² / g or more and a degree of methanol hydrophobicity of 30 to 90%. For toner. 4. The toner for developing an electrostatic charge image according to claim 1, wherein the organically treated alumina powder is an alumina powder that has been subjected to a hydrophobic treatment in a liquid medium. 5. The toner for developing an electrostatic charge image according to claim 1, wherein the organically treated alumina powder is treated with a silane organic compound. 6. The toner for developing an electrostatic charge image according to claim 5, wherein the silane organic compound is a silane coupling agent. 7. The toner for developing an electrostatic charge image according to claim 1, wherein the organically treated alumina powder has a BET specific surface area of 150 m ² / g or more. 8. The toner for developing an electrostatic charge image according to claim 1, wherein the toner has a weight average particle diameter of 3 to 7 μm. 9. The organically treated alumina powder is a toner particle 1.
9. The toner for developing an electrostatic charge image according to claim 1, which is added in an amount of 0.5 to 5 parts by weight per 100 parts by weight. 10. The organically treated alumina powder has a 2θ of 30.
Maximum X-ray intensity level I in the range of 40 to 40 degrees
Ratio of _b-max and minimum X-ray intensity level I _b-min (I _b-max /
10. The toner for developing an electrostatic charge image according to claim 1, wherein I _b-min ) is less than 2.