JPH11184239A - Image forming method - Google Patents

Abstract

(57) [Problem] Even with a small particle size toner, an image can be formed in a stable state with a uniform charge amount, no fog occurs, a high-density image can be obtained, and it is affected by environmental fluctuations. Provided is an image forming method capable of stably providing a good image even in a high-speed machine having a relatively high process speed without using the same. SOLUTION: The process speed is 160 to 300 mm / s, at least the surface of the developer carrier is formed of a resin containing conductive or semiconductive fine powder, and the JIS center of the surface is formed. Line average roughness (Ra) is 0.2
Using a developer carrier having a particle size of at least 1.0 μm, the toner contains at least a binder resin and a colorant as a toner, the acid value of the binder resin is 2 to 70 mgKOH / g, and the weight average particle size is An image forming method using a negatively chargeable toner of 4 to 11 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method for visualizing an electrostatic latent image with toner in electrophotography, electrostatic printing, magnetic recording, and the like.

[0002]

2. Description of the Related Art Conventionally, electrophotography has been disclosed in U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910.
Numerous methods are known as described in Japanese Patent Publication No. JP-B-43-24748 and Japanese Patent Publication No. 43-24748. In general, an electric latent image is formed on a photoreceptor by various means using a photoconductive substance, and then the latent image is developed using a toner. If necessary, the toner is transferred to a transfer material such as paper. After the image is transferred, the image is fixed by heating, pressure, solvent vapor or the like to obtain a copy.

Conventionally, as a developing device for developing a latent image on a latent image carrier with a one-component magnetic toner, for example, a developing device which performs development as follows is known. First, due to the friction between the magnetic toner particles and the friction between the magnetic toner particles and the developing sleeve as the developer carrier, the charge of the electrostatic latent image on the latent image carrier and the polarity opposite to the development reference potential. Is given to the magnetic toner particles. The charged magnetic toner is applied very thinly on the developing sleeve, and is conveyed to the developing area where the latent image carrier (photosensitive drum) and the developing sleeve are opposed with the rotation of the developing sleeve. Further, in the developing area, the magnetic toner is caused to fly toward the electrostatic latent image on the surface of the photosensitive drum by the action of the magnetic field of the magnet immobilized in the developing sleeve, adhered and developed, and developed. The image is visualized as a toner image.

As disclosed in JP-A-57-66433, as a developing sleeve used in such a method, metals such as aluminum, nickel, corrosion-resistant steel (stainless steel), and alloys or compounds containing these metals are used. What has been widely used is one which is formed into a cylindrical shape and the surface of which is processed by electrolysis, blasting, sanding or the like so as to have a predetermined surface roughness. The developing sleeve having the above configuration is inexpensive and can form a high-quality image relatively stably, but on the other hand, is a one-component toner in which the toner is charged by friction with the developing sleeve. In the case of using the toner, it is difficult to adjust the toner charge, and although various measures have been taken from the toner side, the problems relating to non-uniform charging and long-term charging stability cannot be completely solved.

Particularly, in the developing step, in the toner layer formed on the surface of the developing sleeve by the developer layer thickness regulating member, the toner existing in the toner layer near the surface of the developing sleeve has an extremely high charge. Because
The toner is strongly attracted to the surface of the developing sleeve by the mirror force and becomes immobile on the surface of the developing sleeve, so that the toner does not move from the developing sleeve to the latent image on the latent image carrier, and a so-called charge-up phenomenon occurs. Easier to do. In particular, the charge-up phenomenon is likely to occur under low humidity. When such a charge-up phenomenon occurs, the toner in the upper layer of the toner layer formed on the developing sleeve becomes less likely to have a tribo, so that the development amount of the toner is reduced, and as a result, the line image becomes thinner and the solid black becomes black. This causes an adverse effect such as a low image density. Further, on the developing sleeve,
Because the state of formation of the toner layer between the image area (toner consuming section) and the non-image area changes and the charging state changes, the position where the solid image having a high image density is once developed is located at the next rotation of the developing sleeve. When the halftone image is developed at the development position, a phenomenon in which a trace of a previously developed solid image appears on the image, that is, a so-called sleeve ghost phenomenon is likely to occur.

In order to eliminate such a phenomenon, it is necessary to provide a structure capable of controlling the charge amount of the toner in the toner layer formed on the developing sleeve as uniformly as possible. As an attempt to address this, for example, as a method of preventing a rise in the charge amount of the toner locally generated in the toner layer formed on the developing sleeve and stabilizing the charge amount, it is necessary to add conductive powder to the toner. , JP 58
JP-A-66951, JP-A-59-168449, JP-A-59-168460, and the like. It is disclosed in JP-A-59-16851 that conductive zinc oxide is added to toner.
JP-A-168458 and the like, and the use of tin oxide are described in JP-A-59-170847 and the like. According to these methods, the charge amount of the toner is certainly reduced, and the effect of suppressing the above-described charge-up phenomenon is exerted, so that a high-density image can be obtained. However, all of these methods reduce the overall charge amount by attaching conductive powder to a toner having a large charge amount to make the charge amount uniform. Another adverse effect such as a decrease in the property is likely to occur.

Further, in Japanese Patent Application Laid-Open Nos. 61-236559 and 63-2073, cerium oxide fine particles are added to a toner to disperse aggregated silica and toner lumps, thereby improving the chargeability of the toner. There is disclosed a method for causing this to occur. Certainly, according to this method, it is possible to increase the charging ability of the toner.
Since the effect as a polishing agent is great, the surface layer of the latent image carrier is scraped off, whereby the performance of the latent image carrier is reduced and the quality of the copied image may be degraded. This is particularly noticeable when an organic photoreceptor is used as the latent image carrier.

In order to reduce the amount of toner having too high a charge and to provide the toner with an optimal charge amount for developing, a method disclosed in Japanese Patent Application Laid-Open No. Hei 3-12676 and the like has been proposed. In a resin, a coating formed by a coating liquid in which a conductive agent such as carbon or graphite is dispersed is provided on a metal substrate to form a developing sleeve, thereby charging the toner and having an excessively high charge. Proposals have been made to suppress the generation of toner and to give the toner on the developing sleeve an amount of charge suitable for development by using the reflection power of the toner.

Japanese Patent Application Laid-Open No. 4-133077 discloses a uniform semiconductive composite material having a volume resistivity in the range of 10 ⁵ to 10 ⁹ Ω · cm, and a developing sleeve using the same. It is described that an image with excellent image quality can be obtained when copying is performed. on the other hand,
U.S. Pat. No. 4,299,900 proposes a jumping development method using a developer containing 10 to 50% by weight of a magnetic toner having a particle size of 20 to 35 [mu] m. In this method, a magnetic toner is frictionally charged, a thin and uniform toner layer is coated on a developing sleeve, and further, a toner particle size suitable for improving environmental characteristics of the developer is devised. As a proposal for the toner particle size, Japanese Patent Application Laid-Open No. 2-284156 discloses a method in which the coefficient of variation of the volume distribution and the number ratio of the toner having a particle size of 5 μm or less are specified. When used in a machine, it is difficult to maintain good developability throughout due to the occurrence of selective development and the like.

Further, with respect to non-magnetic toner, some developers have been proposed for the purpose of improving image quality. However, for example, see JP-A-51-32
In Japanese Patent No. 44-44, toner having a particle size of 8 to 12 μm is mainly used, the particle size is relatively coarse, and in the toner distribution, the particle size of the toner is 5% or less, 30% by number or less, and 20 μm or more From the characteristic of being less than a few percent, it is assumed that the particle size distribution is relatively broad. As described above, none of the above-mentioned proposals can sufficiently satisfy all the requirements. On the other hand, in recent years, the need for high-speed copiers and digital copiers has been rapidly increasing. To achieve this, the toner is reduced in particle size / particle size.

[0011] However, even if the resolution and sharpness of an image can be increased by digitization and reduction in the particle size of the toner, another problem as described below arises. First of all, there is the problem of fog. That is, when the particle size of the toner is small, the surface area of the toner is increased, so that the width of the charge amount distribution is widened, and as a result, fogging is likely to occur. In addition, the increase in the surface area of the toner makes the charging characteristics of the toner more susceptible to the influence of the environment. Therefore, the charging state of the toner becomes unstable and fogging is liable to occur. Further, when the particle size of the toner is reduced, it is difficult to make the dispersion state of the polar substance and the colorant contained in the toner uniform, which greatly affects the chargeability of the toner. That is, when the dispersion state of the polar substance and the colorant in the toner is not uniform, the width of the charge amount distribution of the toner is widened, so that fog is easily generated.

In recent digital copiers, in a photographic image containing characters, not only are the characters of the copied image clear, but also the photographic image can obtain a density gradation faithful to the original. Is required. In general, when copying a photographic image with characters, if the line density is increased to make the characters clear, not only the density gradation of the photographic image is impaired, but also an image in which the halftone portion is very rough. On the other hand, if the density gradation of the photographic image is to be improved, the density of the character line tends to decrease and the sharpness tends to deteriorate. Thus, it has been difficult to achieve both the sharpness of characters and the density gradation of a photographic image. On the other hand, in recent years, the density gradation has been improved to some extent by reading the image density and performing digital conversion, but at present, it is still not enough.

[0013]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image forming method which solves the above-mentioned problems of the prior art. That is, the object of the present invention is to
Provided is an image forming method capable of forming an image with a uniform and stable charge amount of the toner even without using a toner having a small particle diameter, and producing a high-density copy image without fogging. Is to do. Another object of the present invention is to provide an image forming method capable of stably giving a good image under low humidity environment and high humidity environment without being affected by environmental fluctuation. . Another object of the present invention is to provide an image forming method that can provide a good image stably even in a high-speed machine having a relatively high process speed and has a wide range of applicable models from low-speed machines to high-speed machines. It is in.

Another object of the present invention is to provide a copy image which is excellent in durability of a device using a latent image carrier or the like and has a high image density and has no white background fog even when used continuously for a long period of time. To provide an image forming method. Another object of the present invention is to provide, in a digital copying machine, excellent resolution and fine line reproducibility, and even in a photographic image containing characters, not only that the characters of the copy image are clear,
It is another object of the present invention to provide an image forming method capable of obtaining a density gradation faithful to a document even for a photographic image. Another object of the present invention is to be able to maintain the chargeability of the toner uniformly and stably in any environment, to suppress the occurrence of poor toner coating on the developing sleeve and the occurrence of sleeve ghost, and to obtain a good image. To provide an image forming method.

[0015]

Means for Solving the Problems The above objects are as follows.
This is achieved by the present invention. That is, the first invention of the present invention is an image forming method using a specific negatively chargeable toner, and the second invention of the present invention is an image forming method using a specific positively chargeable toner. First, the first aspect of the present invention is to transfer a negatively chargeable toner onto a latent image carrier for negative charging by a bias voltage applied to a developer carrier, thereby forming a digital latent image on the latent image carrier. In an image forming method for forming a toner image by reversal development of an image, the process speed is 160 to 300 mm / s, and the developer carrier contains at least a fine powder whose surface is conductive or semiconductive. And a JIS center line average roughness (Ra) of 0.2 to 1.0 [mu] m on the surface thereof. And a coloring agent, wherein the binder resin has an acid value of 2 to 70 mgKOH / g and a weight average particle diameter of 4 to 11 μm. It is.

According to a second aspect of the present invention, a positively chargeable toner is transferred onto a positively-charged latent image carrier by a bias voltage applied to the developer-carrying member. An image forming method for forming a toner image by reversal development of the digital latent image of
３００300 mm / s, and at least the surface of the developer carrier is formed of a resin containing conductive or semiconductive fine powder, and the JI
Using a developer carrier having an S center line average roughness (Ra) of 0.2 to 1.0 μm, the toner particles containing at least a binder resin and a colorant as the above-mentioned positively chargeable toner include B
An ET specific surface area of 30 to 50 m ² / g and a powdery metal oxide having a weight average particle diameter of 0.4 to 5.5 μm and a weight average particle diameter of 4 to 11 μm An image forming method using a positively chargeable toner.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail by way of preferred embodiments of the present invention. Demand for copiers has been increasing more and more recently, but as mentioned above, high-speed copiers and digital copiers are particularly remarkable. In addition, users are increasingly demanding higher quality images. It is well known that the toner has been reduced in particle size / particle size in order to achieve high image quality. However, when a toner having a small particle size is used, charge control of the toner ( Tribocontrol) becomes difficult.
The reason for this is that, as described above, if the particle size of the toner is reduced, it becomes difficult to make the dispersion state of the internal components of the toner such as a colorant and a magnetic material uniform in manufacturing. This is because the instability of the dispersion state tends to affect the charging characteristics of the toner. That is, if the dispersion state of these internal components is poor, the toner tribo tends to be non-uniform.

Even if the internal components in the toner can be uniformly dispersed, the charge amount of the toner is affected by the particle size distribution of the toner. That is, in general, the charge amount of a toner having a small particle size is large, and the charge amount of a toner having a large particle size is small. The larger the charge amount of the toner, the wider the width of the charge amount distribution, and the smaller the charge amount, the narrower the charge amount distribution. On the other hand, as regards a method of using a toner having a high charge amount and sharpening the charge amount distribution, many methods have been devised in the past, but none of these methods have been sufficiently satisfactory. Toner tends to cause the toner charge-up phenomenon as described above, and tends to cause deterioration in developability.

On the other hand, as a method of suitably controlling the charge amount of the toner on the developing sleeve, a conductive or semiconductive material such as carbon or graphite is dispersed in a binder resin on the surface of the developing sleeve. A method using a developing sleeve provided with a resin coating layer in a state has been proposed. The present inventor further conducted intensive studies on the improvement of the developing sleeve having the above-described structure, and focused on the surface state of the developing sleeve, and expressed the surface characteristics of the developing sleeve by JIS center line average roughness (Ra). Further, if the developing sleeve is configured so that the Ra value on the surface of the developing sleeve becomes a specific value, an excellent charge providing ability capable of increasing the charge amount of the toner and sharpening the charge amount distribution is achieved. This led to the present invention.

That is, if the developing sleeve having such a configuration is used, generation of a toner having an excessively high charge,
It is possible to effectively prevent the strong toner from adhering to the surface of the developing sleeve due to the reflection force of the toner, and to apply a suitable charge to the toner on the developing sleeve. As a result, it is possible to suppress the charge-up phenomenon and the occurrence of fog. Is achieved. Further, since the charge amount of the toner on the developing sleeve is constantly and uniformly maintained, even when copying is continued for a long time, the "selective development" of the toner generated on the developing sleeve is performed.
It has been found that such a phenomenon can be suppressed, and a high-density, high-quality copy image can be formed stably from beginning to end. Here, the term “selective development” refers to a phenomenon in which only toner having a suitable charge amount at the start of copying contributes to development. Low-volume, coarse-grained toner that is not suitable for development will remain on the developing sleeve or in the developing device and accumulate, and if these toners are used for development, the developability will decrease. Is brought.

Further, as a result of various studies by the present inventor, the present inventors have found out a configuration of a toner having an excellent triboelectric charging property with the developing sleeve. As a result, when a toner having a specific configuration is used for the specific developing sleeve, a synergistic effect of the two makes it possible to increase the charge amount of the toner and to achieve a sharp charge amount distribution, thereby reducing the toner size. Particle size/
Achieving both high image quality due to fine particles and suppression of fogging, resolution in digital copiers, fine line reproducibility, and in photographic images with characters, the clarity of characters in the copied image and It has been found that it is possible to achieve both the density gradation and the like faithful to the original.

That is, the first invention of the present invention contains at least a binder resin and a colorant, or a binder resin and a magnetic substance, and has an acid value of 2 to 70 mgKOH / g. And an image forming method using a specific negatively chargeable toner having a weight average particle diameter of 4 to 11 μm. By using the binder resin having such a configuration, the charge acceptability of the binder resin itself is reduced. In addition, a synergistic effect can be obtained with the excellent charge-imparting ability of the developer-carrying member, the negative triboelectricity of the developer can be improved, and the above-described excellent effect can be obtained.
Further, the second invention of the present invention relates to a toner particle having a weight average particle diameter of 4 to 11 μm containing at least a binder resin and a colorant, or a binder resin and a magnetic substance, and having a BET specific surface area of 30 μm.
流動 50 m ² / g fluidizing agent and weight average particle size of 0.4 粒径
This is an image forming method using a specific positively chargeable toner containing 5.5 μm powder metal oxide. According to the image forming method, by including a fluidizing agent in the toner, the fluidity of the toner is improved and the developability is also improved, and the metal oxide contained in the toner is brought into contact with the toner. By doing so, the charge amount of the toner having a low charge amount in the charge amount distribution can be increased, and as a result, a uniformly charged toner can be obtained, and the synergistic effect with the excellent charge providing ability of the developer carrier described above can be obtained. In order to achieve the excellent effects of the present invention. Furthermore, according to the study of the present inventors, it has been found that a more excellent effect is exhibited by using a metal oxide as a composite metal oxide.

First, the structure of a developer carrying member (hereinafter, also referred to as a developing sleeve) which characterizes the image forming method of the present invention as described above will be described. In the image forming method of the present invention, at least the surface is formed of a resin containing a conductive or semiconductive fine powder, and the surface has a JIS center line average roughness (Ra) of 0.1. It is characterized in that a developer carrier having a thickness of 2 to 1.0 μm is used. As a preferred embodiment of the developing sleeve used in the present invention, for example, a base comprising a metal cylindrical tube or the like,
A resin layer that is coated around the outer periphery of the base, and the surface of the resin layer is configured to have a specific surface roughness. As the base of the developing sleeve as described above, a metal cylindrical tube of stainless steel, aluminum or the like is preferably used. And
The resin layer formed on the surface of such a base is composed of a binder resin and conductive or semiconductive fine powder dispersed in the resin. In the present invention, the term “conductive or semiconductive” means that the volume resistivity is 10 ⁻⁴ to 10 ⁵ Ω · cm.
Range. A preferable volume resistance value of the fine powder used in the present invention is 10 ⁻² to 10 ³ Ω · cm.
Range. The volume resistance value of the fine powder is a value measured by placing 1 g of the sample in a cylindrical container having a cross section of 1 cm ² and applying a voltage of 500 V under a pressure of 1 kg. Hereinafter, the resin layer formed on the surface of the developing sleeve will be described.

As the conductive or semiconductive fine powder used for forming the resin layer, for example, aluminum,
Copper, nickel, metal powders such as silver, potassium titanate, metal compounds such as barium ferrite, short metal fibers, carbon fibers, for example, antimony oxide, indium oxide, tin oxide, conductive metal oxides such as zinc oxide, For example, carbon fine particles, conductive fine powder such as graphite and the like can be mentioned. Of these, graphite, especially crystalline graphite, has lubricity as well as conductivity, so if it is contained in the resin layer formed on the surface of the developing sleeve, it is possible to reduce toner adhesion to the developing sleeve. It is suitably used in the image forming method of the present invention.

Here, crystalline graphite is roughly classified into natural graphite and artificial graphite. What is artificial graphite?
For example, after solidifying pitch coke with a tar pitch or the like, it is fired once at about 1,200 ° C., and then put into a graphitization furnace and treated at a high temperature of about 2,300 ° C. to grow carbon crystals. This was changed to graphite. Natural graphite, on the other hand, is completely graphitized by geothermal heat and underground high pressure for a long time, and is produced from underground. Each of these graphites has various excellent properties, and has a wide industrial use. That is, these graphites are dark gray to black glossy, very soft, lubricious carbon crystals, and are used in pencils and the like, and because they have heat resistance and chemical stability, they have lubricity. It is used in the form of powders, solids, and paints as materials, refractory materials, electric materials, and the like. The crystal structure of graphite includes a rhombohedral system as a hexagonal system, and has a complete layered structure. Regarding the electrical properties of graphite, free electrons are present between the bonds between carbon and carbon, making it a good conductor of electricity. In the image forming method of the present invention, by including such a substance in the resin layer formed on the surface of the developing sleeve, excellent charging ability is achieved. In the present invention, as the conductive material,
Both natural and artificial graphite can be used. The particle size of the graphite used is preferably about 0.5 μm to 20 μm.

As the carbon fine particles usable in the present invention, conductive amorphous carbon can be used. The conductive amorphous carbon is generally defined as "an aggregate of crystallites formed by burning or thermally decomposing a compound containing a hydrocarbon or carbon in a state in which air supply is insufficient." In particular, since it has excellent electric conductivity, it can be filled with a polymer material to impart conductivity, and furthermore, it can be given an arbitrary conductivity to some extent by controlling the amount of addition, so that it is widely used. In the image forming method of the present invention, as the conductive material contained in the resin layer formed on the surface of the developing sleeve, it is preferable to use conductive amorphous carbon having a particle size of 10 to 80 nm, more preferably 15 to 80 nm.
It is more preferable to use one having a particle size of 40 nm.

The conductive or semiconductive fine powder made of the above-mentioned material is used in an amount of 20 to 200 parts by mass, preferably 30 to 150 parts by mass, per 100 parts by mass of the binder resin constituting the resin layer. It is good to add in the range of a part. If the amount is less than 20 parts by mass, the effect of the added fine powder is poor, and it is difficult to optimize and uniform the charge amount of the toner on the developing sleeve. If the amount is more than 200 parts by mass, not only the dispersion of the fine powder in the binder resin tends to be uneven, but also the strength of the film itself tends to deteriorate.
Further, the conductivity of the developing sleeve itself becomes too high, and it becomes difficult to give an appropriate tribo to the toner.

In the image forming method of the present invention, a resin layer containing the above-mentioned conductive or semiconductive fine powder is provided on the surface of the developing sleeve. For example, the following can be used. Specifically, for example, styrene resin, vinyl resin, polyether sulfone resin, polycarbonate resin, polyphenylene oxide resin, polyamide resin, fluororesin, cellulose resin, thermoplastic resin such as acrylic resin; epoxy resin; Polyester resin, alkyd resin, phenol resin, melamine resin,
Thermosetting resins such as polyurethane resins, urea resins, silicone resins, and polyimide resins; and photocurable resins. In the present invention, among these, silicone resins, those having a releasable property such as fluororesin, or polyethersulfone resin, polycarbonate resin,
It is more preferable to use a resin having excellent mechanical properties, such as a polyphenylene oxide resin, a polyamide resin, a phenol resin, a polyester resin, a polyurethane resin, and a styrene resin.

As a method for forming a resin layer on the surface of the developing sleeve by using the composite material containing the conductive or semiconductive fine powder and the binder resin as described above, the following method is exemplified. For example, after the raw material mixture as described above is sufficiently dispersed in a resin using a disperser such as a sand mill, the obtained dispersion is diluted with an organic solvent to form a coating liquid, and sprayed. A coating solution may be applied to the developing sleeve substrate by a method or the like, dried and cured to form a film, thereby producing a resin-coated sleeve having a resin layer on the surface.

In the above-described example, the developing sleeve is formed by forming a resin layer containing a conductive or semiconductive fine powder on the surface of a base made of a metal such as aluminum.
In the present invention, it is also possible to use a resin sleeve formed of a resin containing conductive or semiconductive fine powder without using a base. In this case, as the conductive or semiconductive material, the same material as that used as the material for forming the resin layer described above can be used.

Further, as the binder resin used in this case,
From the viewpoint of workability, for example, in order to easily obtain a tubular resin, it is preferable to use a material that can be extruded or injection-molded. Any material may be used as long as it is such, but in the present invention, it is particularly preferable to use a crystalline resin. That is, since the crystalline resin is easy to form a passage of the conductive powder along the peripheral surface of the resin crystal region, it is necessary to make the entire developing sleeve the same conductivity as compared with the case of the matrix made of the non-crystalline resin. This is preferable because the amount of the conductive powder can be small. Examples of the crystalline resin that can be used in the present invention include a polyamide resin, a polypropylene resin, a polyethylene resin, a polypropylene oxide resin, and a polybutylene terephthalate resin. Also, using these resins, in order to produce a resin composite material consisting of these resins and conductive or semiconductive fine powder, for example, while kneading the crystalline resin in a twin-screw kneading extruder, A conductive or semiconductive fine powder may be added, and the kneaded material may be pelletized with a pelletizer. If the pellets thus formed are molded by an extruder or the like, for example, a cylindrical resin sleeve can be easily manufactured.

When a resin layer is provided on the surface of the base, the JIS center line average roughness (Ra) of the resin layer surface of the developing sleeve formed of the above-mentioned material used in the image forming method of the present invention is used. However, in the case of a resin sleeve, the JIS center line average roughness (Ra) of the surface thereof is 0.2 to 1.0.
μm, preferably 0.3 to 0.8 μm. In order to form the surface having the roughness as described above, after producing the developing sleeve, a pressure of about 3 to 4 kgf / cm ² is applied by using a woven felt, a wrapping tape, a fine sandpaper of about # 3000 or the like. Then, the surface of the developing sleeve may be polished. Further, after polishing, in order to remove stains on the surface of the developing sleeve adhered in a polishing process or the like,
Washing with an alcohol such as ethanol or methanol is preferred. This is because the rise of the charge of the toner may be deteriorated due to the influence of the stain attached to the surface of the developing sleeve.

In the image forming method of the present invention, the JIS center line average roughness (Ra) of the developing sleeve surface is 0.2 μm.
If less than, the toner layer carried on the developing sleeve becomes too thin, the coating tends to be non-uniform,
It is not preferable because the charge of the toner becomes too high and a charge-up phenomenon easily occurs. On the other hand, if it exceeds 1.0 μm, the toner layer carried on the developing sleeve becomes too thick, and uniform charging of the toner is hindered, and fogging is likely to occur on an image.

Next, the image forming method of the present invention using the above-described developing sleeve will be described. In general,
When applied to a digital copying machine or a laser beam printer, it is considered that a steep (γ) of the potential contrast-density characteristic (VD characteristic) is preferable from the viewpoint of stable image density. In the image forming method of the present invention, in order to achieve good image quality and density stability irrespective of digital / analog, the JI as described above is required.
By using a developing sleeve having a small S center line average roughness (Ra) of 0.2 to 1.0 μm, a developer (toner) layer formed thereon is formed as a thin coat layer and a developing sleeve is formed. Peripheral speed (anti-latent image carrier), high V
_pp , and a high frequency is preferable.

In the image forming method of the present invention, the absolute value of the alternating bias voltage applied to the developing sleeve is 500
V or more, preferably considering leakage to the latent image carrier,
It is good to be 500-1500V. However, this leak varies depending on the setting of the gap between the developing sleeve and the latent image carrier. In the present invention, the alternating bias frequency is preferably in the range of 1,000 to 5,000 Hz. That is, when the alternating bias frequency is less than 1,000 Hz, although the gradation of the obtained image is improved,
It is difficult to eliminate fog. This is because, in a low-frequency region where the number of reciprocating movements of the toner is small, the toner biasing force against the latent image carrier due to the developer bias electric field becomes too strong even in the non-image area. It is considered that the reason is that the toner attached to the non-image portion cannot be completely removed even by the removing force. On the other hand, if the frequency exceeds 5,000 Hz,
Since the bias electric field on the reverse development side is applied before the toner sufficiently contacts the latent image carrier, the developability decreases. That is, the toner itself cannot respond to the high frequency electric field. According to the study of the present inventors, in the present invention, the frequency of the alternating bias electric field is set to 1,500 Hz to 3,
It was confirmed that the optimum image quality was exhibited at 000 Hz.

Further, in the image forming method of the present invention,
It is also preferable to use an asymmetric bias as shown in FIGS. 1 and 7 as the alternating electric field. In the case of the asymmetric bias shown in FIG. 1, the negative toner used in the first invention of the present invention is used for the positive latent image potential, and the positive charge toner is used. In the asymmetric bias of No. 7, the toner of the positive polarity used in the second invention of the present invention is used for the latent image potential of the negative polarity, and the potential of the developing sleeve is used as a reference (the potential of the developing sleeve is set to zero). ) And a are the developing side bias components, and b is the reverse developing side bias component. At this time, the magnitudes of the developer bias component and the reverse development side bias component are respectively Va
And the absolute value of Vb. The duty ratio in the alternating bias electric field is defined as in the following equation.

[0037] [In the above equation, ta is a polarity component in the direction in which the developer is transferred to the latent image carrier side in one cycle of the AC bias in which the electric field polarity periodically alternates between positive and negative (constituting a developing-side bias component a. ) Indicates the application time, and tb indicates the application time of the polarity component (constituting the reverse development side bias component b) in the direction of separating the developer from the latent image carrier side. ]

In the image forming method of the present invention, the duty ratio that satisfies the alternating bias electric field waveform determined by the above equation may be set to be about 60% or less. The ratio should be ≤60%. When the duty ratio exceeds 60%, the effect on high image quality is weakened. When the duty ratio is less than 10%, as described above, the alternating bias electric field response of the developer itself is deteriorated, and the developability is reduced.

Further, as a waveform of the alternating bias which can be used in the present invention, any waveform such as a rectangular wave, a sine wave, a sawtooth wave, and a triangular wave can be applied. In the image forming method of the present invention, the peripheral speed of the developing sleeve (with respect to the latent image carrier) is preferably set to 105 to 200%. When the peripheral speed of the developing sleeve (with respect to the latent image carrier) is less than 105%, it becomes difficult to maintain the density stability during the durability. 2
If it exceeds 00%, toner scattering from the developing sleeve is likely to occur, which is not preferable (especially when a high-speed copying machine is used).

Next, the toner used in combination with the developing sleeve in the image forming method of the present invention will be described. Hereinafter, the case of the first invention of the present invention using a negatively chargeable toner and the case of the second invention of the present invention using a positively chargeable toner will be separately described. (First Invention of the Present Invention) First, the negatively chargeable toner used in the first invention of the present invention will be described. The negatively chargeable toner used in the first invention is at least a binder resin and a colorant,
Alternatively, it is a negatively chargeable toner containing a binder resin and a magnetic substance, wherein the binder resin has an acid value of 2 to 70 mgKOH / g and a weight average particle size of 4 to 11 μm. Further, among them, in the particle size distribution of the toner, when the standard deviation of the number distribution is S _n and the length average particle diameter (μm) based on the number is D ₁ , the number distribution variation coefficient A represented by the following equation is 40. % Or less is preferably used. A = S _n / D ₁ × 100

As described above, in the first aspect of the present invention, a negatively chargeable toner having a weight average particle diameter of 4 to 11 μm is used. That is, in the case of a toner having a weight average particle size exceeding 11 μm, adverse effects such as a reduction in image resolution and a decrease in density during continuous copying are likely to occur. On the other hand, when the weight average particle diameter of the toner is less than 4 μm, it becomes difficult to control the charge amount of the toner.

If the value of the number distribution variation coefficient A exceeds 40% in the particle size distribution of the toner, particles larger or smaller than the average particle size are present. In the case of toner, the aggregation state of the toner particles is likely to occur, and a toner lump having a larger particle diameter than the original toner is generated, which may cause adverse effects such as inhibition of charging and deterioration of image quality. Furthermore, in the case of a particle size distribution in which the value of the number distribution variation coefficient A exceeds 40% regardless of magnetic / non-magnetic, the charge balance of the toner particles is disrupted, and the particle size having an unnecessary charge is small. The toner easily becomes charged and adheres to the developing sleeve (in the case of a two-component system, further to the carrier surface), which hinders normal toner from being carried or charged on the developing sleeve, or causes a large particle size with insufficient charging. When the toner covers the toner layer,
Developability tends to decrease, resulting in fog and image density. Therefore, in the present invention, it is preferable to use a toner having a number distribution variation coefficient A of 40% or less in the particle size distribution of the toner.

Here, the particle size distribution of the toner can be measured by various methods. In the first invention, the measurement is performed using a Coulter counter. That is, a Coulter Counter TA-II or Coulter Multisizer II (manufactured by Coulter Inc.) is used as a measuring device. About 1% NaCl aqueous solution is prepared using primary grade sodium chloride as an electrolyte. Commercially available products include, for example, ISOTON-II (manufactured by Coulter Inc.)
Can be used. The measuring method is as follows.
In 0 to 150 ml, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic
The volume distribution and the number distribution were calculated by measuring the volume and the number of the toners using the m aperture. Then, the weight-based weight average particle diameter (D ₄ ) obtained from the volume distribution according to the first invention (the median value of each channel is set as a representative value for each channel), and the number-based weight obtained from the number distribution The length average particle diameter (D ₁ ) and its standard deviation (S _n ) were determined.

Next, the binder resin constituting the negatively chargeable toner used in the first invention of the present invention will be described. The binder resin used in the negatively chargeable toner used in the first invention of the present invention has an acid value of 2 to 70 mgKOH / g, preferably 5 to 50 mgKOH / g. This is because, by using the binder resin having such a configuration, the charge acceptability of the binder resin itself is increased, and the synergistic effect with the excellent charge providing ability of the developer carrier described above is used.
This is because the negative triboelectric charging property of the developer can be improved. That is, when a binder resin having an acid value of less than 2 mgKOH / g is used, the frictional charging ability of the developer is insufficient, so that the image density is reduced and the fog is deteriorated. This is particularly noticeable under low humidity. On the other hand, 70 mgK
When a binder resin exceeding OH / g is used, the charge relaxation effect of the acid group becomes too large, resulting in a decrease in image density. This is particularly noticeable under high humidity. still,
The acid value of the binder resin in this case is a value measured by a method according to JIS K-0070. Examples of the binder resin of the toner having the above-described configuration include a vinyl resin, a polyester resin, a polyurethane resin, an epoxy resin, and a phenol resin. Among these, a vinyl resin and a polyester resin are particularly preferable. .

As the carboxylic acid-containing monomer which can be used for synthesizing a vinyl resin having an acid value of 2 to 70 mgKOH / g, a half-ester monomer of dicarboxylic acid is particularly preferable. For example, monomethyl maleate, monoethyl maleate, Monobutyl maleate, monooctyl maleate, monoallyl maleate, monophenyl maleate, monomethyl fumarate, monoethyl fumarate,
Half-esters of α, β-unsaturated dicarboxylic acids such as monobutyl fumarate and monophenyl fumarate; monobutyl n-butenylsuccinate, monomethyl n-octenylsuccinate, monoethyl n-butenylmalonate, n-dodecenyl glutar Half esters of alkenyl dicarboxylic acids such as monomethyl acrylate, monobutyl n-butenyl adipate and the like; half esters of aromatic dicarboxylic acids such as monomethyl phthalate, monoethyl phthalate, monobutyl phthalate and the like; Is mentioned.

The above-mentioned half-ester of dicarboxylic acid may be added in an amount of 1 to 30% by mass, preferably 3 to 20% by mass, based on all monomers constituting the binder resin. The reason for selecting the dicarboxylic acid half-ester monomer as described above will be described in detail later,
In the case of producing a resin from these monomers, it is preferable to produce the resin by a suspension polymerization method. However, in the suspension polymerization method, it is appropriate to use an acid monomer having high solubility in an aqueous suspension. This is because it is preferable to use an ester having low solubility.

The acid value used in the present invention is 2 to 70 mg KO
Examples of comonomers other than the dicarboxylic acid half-ester monomer used for obtaining the vinyl resin having H / g include the following. For example,
Styrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert -Styrene such as -butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene and derivatives thereof; ethylene, propylene, butylene Unsaturated ethylenes such as butadiene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride;
Vinyl acetate, vinyl propionate, vinyl esters such as benzoic acid; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate;
Isobutyl methacrylate, n-octyl methacrylate,
Α-methylene aliphatic monocarboxylic esters such as dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, Acrylic esters such as n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl compounds such as nilpyrrole, N-vinylcarbazole, N-vinylindole and N-vinylpyrrolidone; vinylnaphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide; Alternatively, two or more are used. Among these, it is preferable to use a vinyl-based resin obtained by a combination of monomers to form a styrene-based copolymer or a styrene / acrylic-based copolymer.

As a synthesis method for synthesizing a vinyl resin which can be suitably used in the image forming method of the present invention from the above-mentioned monomers, a method for synthesizing two or more polymers is basically used. Preferably, it is used. That is,
In this method, a low molecular weight polymer soluble in a polymerization monomer is dissolved in the polymerization monomer, and the monomer is polymerized to obtain a resin composition. According to such a synthesis method, a resin composition containing the former and the latter polymers in a uniform ratio can be obtained. still,
The low molecular weight polymer used here can be obtained by a commonly used polymerization method such as a bulk polymerization method and a solution polymerization method.

In the present invention, among them,
It is preferred to obtain a low molecular weight polymer by solution polymerization.
That is, by polymerizing at a high temperature and increasing the termination reaction rate,
Although a low molecular weight polymer can be obtained by the bulk polymerization method, there is a problem that the reaction is difficult to control. On the other hand, in the solution polymerization method, a low molecular weight polymer or copolymer having desired characteristics can be freely used by utilizing a difference in chain transfer of radicals depending on a solvent, or by adjusting an amount of a polymerization initiator or a reaction temperature. Can be easily obtained under mild conditions.

Here, the solvent used in the solution polymerization method includes, for example, xylene, toluene, cumene, cellosolve acetate, isopropyl alcohol, benzene and the like. These solvents may be appropriately selected depending on the polymer to be polymerized. For example, in the present invention, when a styrene monomer mixture is used, xylene, toluene or cumene is preferably used. Further, as a polymerization initiator used in the solution polymerization method, for example, di-ter
t-butyl peroxide, tert-butyl peroxybenzoate, benzoyl peroxide, 2,2 ′
-Azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile) and the like.
The polymerization initiator was used in an amount of 0.0
The concentration is preferably 5 parts by mass or more, preferably 0.1 to 15 parts by mass. The reaction temperature varies depending on the solvent used, the polymerization initiator or the polymer to be polymerized.
Preferably, the temperature is 230 ° C. In the solution polymerization, it is preferable to perform the synthesis using a monomer in an amount of 30 to 400 parts by mass with respect to 100 parts by mass of the solvent. Further, at the end of the polymerization, the reaction may be terminated by mixing another polymer or copolymer in the solution. By doing so, a resin composition in which several kinds of polymers or copolymers are uniformly mixed can be obtained.

In order to obtain a high molecular weight component in a highly crosslinked region, it is preferable to use a polymerization method such as an emulsion polymerization method or a suspension polymerization method. Among them, the emulsion polymerization method is a method in which a monomer almost insoluble in water is dispersed as small particles in an aqueous phase with an emulsifier, and polymerization is carried out using a water-soluble polymerization initiator. According to this method, the reaction heat can be easily adjusted, and the phase in which the polymerization is performed (oil phase composed of a polymer and a monomer).
And the aqueous phase are separate, so that the termination reaction rate is low, and as a result, a polymerization rate is high and a polymer having a high degree of polymerization is obtained. Furthermore, the polymerization process is relatively simple, the polymerization product is fine particles, the colorant and charge control agent used in the toner manufacturing process, other additives, and these, and the binder resin This is advantageous as compared with other methods as a method for producing a binder resin for a toner because it is easy to mix. However, in the emulsion polymerization method, since the emulsifier is added, the produced resin tends to contain impurities, and an operation such as salting out is required to take out the resin. Therefore, when producing the binder resin used in the present invention,
The suspension polymerization method described below is preferred because it is simple.

In the suspension polymerization method, a monomer mixture containing a low molecular weight polymer or a copolymer is polymerized together with a crosslinking agent in a suspension state, whereby the obtained resin composition has a pearl-like shape. In addition, it contains a low molecular weight polymer or copolymer and a cross-linking region component, and is in a state where the medium and high molecular weight polymer or copolymer component is uniformly contained in the resin. Such a resin composition is in a preferable state as a binder resin used in the present invention.

In the suspension polymerization method, specifically, the polymerization is carried out at 100 parts by mass or less, preferably 10 to 90 parts by mass, with respect to 100 parts by mass of water or an aqueous solvent. Examples of dispersants that can be used at this time include polyvinyl alcohol, partially saponified polyvinyl alcohol, and calcium phosphate. The amount of the dispersant used varies depending on the amount of the monomer with respect to the aqueous solvent, but is generally about 0.05 to 1 part by mass per 100 parts by mass of the aqueous solvent. The polymerization temperature is suitably from 50 to 95 ° C., but may be appropriately selected depending on the initiator used and the type of the intended polymer. Any kind of polymerization initiator can be used as long as it is insoluble or hardly soluble in water. For example, benzoyl peroxide, tert-butyl peroxyhexanoate, or the like may be used in the range of 0.5 to 10 parts by mass based on 100 parts by mass of the monomer.

The crosslinking agent used in this case includes:
A crosslinkable monomer having mainly two or more polymerizable double bonds can be used. Among these, aromatic divinyl compounds are preferable, and specifically, for example, divinylbenzene, divinylnaphthalene, and the like; diacrylate compounds linked by an alkyl chain, for example, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate , 1,4-butanediol diacrylate,
1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and those obtained by replacing acrylate of these compounds with methacrylate; diacrylate linked by an alkyl chain containing an ether bond Compounds such as diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and methacrylates of the acrylates of these compounds Diacrylate compounds linked by a chain containing aromatic and ether bonds, for example, polyoxyethylene (2) -2,2- Scan (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -
2,2-bis (4-hydroxyphenyl), propane diacrylate, and those obtained by replacing acrylates of these compounds with methacrylates; further, polyester-type diacrylate compounds, for example, trade name MANDA
(Nippon Kayaku) and the like. Examples of the multifunctional crosslinking agent include pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, oligoester acrylate, and those obtained by replacing acrylate of these compounds with methacrylate; Allyl cyanurate, triallyl trimellitate; and the like.

In the image forming method of the present invention, among the vinyl resins thus obtained, the glass transition temperature is 45 to 80 ° C., preferably 55 to 70 ° C.
A binder having a number average molecular weight Mn of 2,500 to 50,000 and a weight average molecular weight Mw of 10,000 to 1,000,000 is used as a binder resin of the negatively chargeable toner used in the first invention of the present invention. It is preferred to use.

As the polyester resin suitable for the binder resin of the negatively chargeable toner used in the first invention of the present invention, a polyester resin comprising a polycondensate of a polyvalent carboxylic acid component and a polyvalent alcohol component is used. It is preferable to use At this time, the composition of the polyester resin that can be suitably used is as follows. First, as the dihydric alcohol component, for example, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentane Diol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, bisphenol represented by the following formula (A) and derivatives thereof, represented by the following formula (B) Diols and the like.

[0057] (In the formula (A), R is an ethylene or propylene group,
x and y are each an integer of 0 or more, and the average value of x + y is 0 to 10. )

[0058]

Examples of the divalent acid component to be polycondensed with the above-mentioned dihydric alcohol component include benzenedicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid and phthalic anhydride or anhydrides thereof, and lower alkyls. Esters; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid or anhydrides thereof, lower alkyl esters; alkenyl succinic acids or alkyl succinic acids such as n-dodecenyl succinic acid, n-dodecyl succinic acid, or acids thereof And unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, and itaconic acid, and dicarboxylic acids such as anhydrides and lower alkyl esters, and derivatives thereof.

When the above-mentioned dihydric alcohol and polyhydric acid component are polycondensed, a trihydric or higher alcohol component and a trihydric or higher acid component are used in combination, which also serve as a crosslinking component described below. can do. Examples of the trihydric or higher polyhydric alcohol component include, for example, sorbitol, 1,2,2
3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol,
1,2,5-pentanetriol, glycerol, 2-
Methylpropanetriol, 2-methyl-1,2,4-
Examples thereof include polyhydric alcohols having a valency of 3 or more such as butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5-trihydroxybenzene.

Examples of the trivalent or higher polycarboxylic acid component include trimellitic acid, pyromellitic acid,
2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid,
2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8- Polyhydric carboxylic acids such as captan tetracarboxylic acid, empole trimer acid, their anhydrides, lower alkyl esters, tetracarboxylic acids represented by the following formula (C), and their anhydrides, lower alkyl esters; And derivatives thereof.

[0062] (In the formula (C), X represents an alkylene group or alkenylene group having 5 to 30 carbon atoms having at least one side chain having 3 or more carbon atoms.)

Further, among the polyester resins thus obtained, those suitable as a binder resin for the toner used in the image forming method of the present invention have a glass transition temperature of 50 to 75 ° C., preferably 55 to 75 ° C. 65 ° C., and further, the number average molecular weight Mn is from 1,500 to 10,000.
0, preferably 2,000 to 7,000, and a weight average molecular weight Mw of 6,000 to 200,000, preferably 1
Preferred are resins from 000 to 150,000.

The negatively chargeable toner used in the image forming method of the first invention of the present invention is preferably composed of the above-mentioned components. However, it is necessary to further stabilize the chargeability. Accordingly, a charge control agent for controlling the toner to be negatively charged may be added to the toner. At this time, the charge control agent was added in an amount of 0.1 per 100 parts by mass of the binder resin.
10 to 10 parts by weight, preferably about 0.1 to 5 parts by weight. Any conventionally known charge control agent can be used. Today, charge control agents known in the art include: Organometallic complexes and chelate compounds are effective as negatively charge controlling agents. Specific examples include a monoazo metal complex, an aromatic hydroxycarboxylic acid-based metal complex, and an aromatic dicarboxylic acid-based metal complex. aside from that,
Aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives of bisphenol can be mentioned.

When a negatively chargeable magnetic toner is used as a developer in the image forming method of the first invention of the present invention, a magnetic material is contained in the toner. And the following. For example, iron oxides such as magnetite, maghemite, ferrite, and other metal oxides; Fe, Co,
Metals such as Ni, or these metals and Al, Co,
Cu, Pb, Mg, Ni, Sn, Zn, Sb, Be, B
Examples thereof include alloys with metals such as i, Cd, Ca, Mn, Se, Ti, W, and V, and mixtures thereof. As a specific magnetic material, iron trioxide (Fe ₃
O ₄ ), iron sesquioxide (γ-Fe ₂ O ₃ ), zinc iron oxide (Z
nFe ₂ O ₄ ), yttrium iron oxide (Y ₃ Fe ₅ O ₁₂ ),
Iron cadmium oxide (CdFe ₂ O ₄ ), iron gadolinium oxide (Gd ₃ Fe ₅ O ₁₂ ), iron oxide copper (CuFe ₂ O ₄ ), iron oxide lead (PbFe ₁₂ O ₁₉ ), nickel iron oxide (NiFe ₂
O ₄ ), iron neodymium oxide (NdFe ₂ O ₃ ), barium iron oxide (BaFe ₁₂ O ₁₉ ), magnesium iron oxide (MgF
e ₂ O ₄ ), iron manganese oxide (MnFe ₂ O ₄ ), lanthanum iron oxide (LaFeO ₃ ), iron powder (Fe), cobalt powder (Co), nickel powder (Ni) and the like are known. In the present invention, the above-described magnetic materials may be used singly or in a combination of two or more kinds as appropriate. Particularly preferred magnetic materials in the present invention are fine powders of triiron tetroxide or γ-iron sesquioxide.

These ferromagnetic materials used in the present invention have an average particle size of about 0.1 to 2 μm, and have a diameter of 795.
8 kA / m magnetic properties of (10 kilo-oersted) applied, the coercive force (H _c) 1.6~16kA / m, saturation magnetization ^{_{(σ s) 50~200Am 2 / kg}} , a residual magnetization (sigma _r) 2
It is preferred for ~20Am ² / kg. The content of the magnetic material is 10 to 200 parts by mass, preferably 20 to 150 parts by mass, based on 100 parts by mass of the binder resin. These magnetic materials also act as colorants.

The colorant that can be used in the negatively chargeable toner used in the image forming method of the present invention includes, in addition to the magnetic material,
Pigments or dyes conventionally used in toners can be appropriately used. Examples of the pigment used at this time include, for example, carbon black, aniline black, acetylene black, naphthol yellow, hansa yellow, rhodamine lake, alizarin lake, bengara, phthalocyanine blue, indanthrene blue, and the like.
It is preferable to use these pigments in an amount of preferably 0.1 to 20 parts by mass, more preferably 1 to 10 parts by mass, based on 100 parts by mass of the resin. Examples of the dye include azo dyes, anthraquinone dyes, xanthene dyes, and methine dyes. These dyes are used in an amount of 0.1 to 20 parts by mass, preferably 0.1 to 20 parts by mass, based on 100 parts by mass of the resin. It is preferable to use in the range of 3 to 10 parts by mass.

The negatively chargeable toner used in the image forming method of the present invention may contain one or more release agents, if necessary. As a release agent,
The following are mentioned. For example, aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, and paraffin wax, and oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax, or block copolymers thereof A wax mainly containing a fatty acid ester such as carnauba wax, sasol wax and montanic acid ester wax; and a partially or entirely deoxidized fatty acid ester such as deoxidized carnauba wax.

Further, saturated straight-chain fatty acids such as palmitic acid, stearic acid and montanic acid, unsaturated fatty acids such as brandic acid, eleostearic acid and barinaric acid, stearyl alcohol, aralkyl alcohol, behenyl alcohol, seryl alcohol, meryl alcohol Saturated alcohols such as sil alcohol, polyhydric alcohols such as sorbitol,
Fatty acid amides such as linoleic acid amide, oleic acid amide, lauric acid amide, saturated fatty acid bisamides such as methylenebisstearic acid amide, ethylenebiscapramide, ethylenebislauric acid amide, hexamethylenebisstearic acid amide, ethylenebis Oleic acid amide, hexamethylenebisoleic acid amide, N,
Unsaturated fatty acid amides such as N'-dioleyl adipamide, N, N'-dioleyl sebacic amide, and aromatic compounds such as m-xylene bisstearic acid amide and N, N'-distearyl isophthalic amide Fatty acid metal salts such as bisamides, calcium stearate, calcium laurate, zinc stearate, and magnesium stearate (commonly referred to as metal soaps), and aliphatic hydrocarbon waxes and vinyl monomers such as styrene and acrylic acid Waxes grafted with
Examples include partial esterified products of fatty acids such as behenic acid monoglycerin and polyhydric alcohols, and methyl ester compounds having a hydroxy group obtained by hydrogenation of vegetable oils and the like.

The amount of the release agent added to the toner is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the binder resin. These release agents are usually prepared by dissolving a binder resin in a solvent, raising the temperature of the resin solution, and adding and mixing the release agent therein while stirring, or when producing a toner. When kneading the forming material, the above-mentioned release agent can be mixed into the binder resin by mixing.

Further, the negatively chargeable toner used in the first invention of the present invention may contain a fluidizing agent. As a fluidizing agent that can be used at this time, before and after adding the fluidizing agent to the colorant-containing resin particles composed of the binder resin and the colorant,
When comparing the fluidity of the toner, any material that can increase the fluidity of the toner can be used. As the fluidizing agent used at this time, for example, fluorine-based resin powder such as vinylidene fluoride fine powder, polytetrafluoroethylene fine powder, fine powder silica such as wet-process silica, dry-process silica, etc. Examples thereof include silica, titanium oxide, and aluminum oxide (preferably hydrophobic), which have been surface-treated with a ring agent, a titanium coupling agent, silicon oil, or the like. As the fluidizing agent preferably used in the present invention, a fine powder generated by gas-phase oxidation of a silicon halide compound may be mentioned. This is what is called so-called fumed silica or fumed silica, and is manufactured by a conventionally known technique. For example, it utilizes the thermal decomposition oxidation reaction of silicon tetrachloride gas in an oxyhydrogen flame, and the basic reaction formula is as follows. SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl

In this manufacturing process, it is possible to obtain a composite fine powder of silica and another metal oxide by using another metal halide such as aluminum chloride or titanium chloride together with a silicon halide. The fluidizing agent used in the first invention also includes them. Also, as the particle size of these fluidizers,
The average primary particle size is desirably in the range of 0.001 to 2 μm, and particularly preferably 0.002 to 2 μm.
It is preferable to use a fine silica powder within a range of 0.2 μm. Further, in the present invention, the fine silica powder produced by the gas phase oxidation of the silicon halide compound as described above,
It is more preferable to use a treated silica fine powder subjected to a hydrophobic treatment. As the hydrophobic treatment method, the silica fine powder may be chemically treated with an organic silicon compound or the like which reacts or physically adsorbs with the silica fine powder.

[0073] As the fluidizing agent used in the negatively chargeable toner used in the first invention, the specific surface area by measuring nitrogen adsorption by the BET method is 30 m ² / g or more, preferably 50 m ² /
g or more give good results. The amount of the fluidizing agent to be added may be 0.01 to 8 parts by mass, preferably 0.1 to 4 parts by mass, based on 100 parts by mass of the toner.

As other additives, for example, lubricants such as Teflon, zinc stearate and polyvinylidene fluoride are preferable, and polyvinylidene fluoride is particularly preferable. Alternatively, for example, abrasives such as cerium oxide, silicon carbide, and strontium titanate are preferable, and among them, strontium titanate is preferable. Also, anti-caking agents, or, for example,
Conductivity-imparting agents such as carbon black, zinc oxide, antimony oxide, and tin oxide, and white and black fine particles of opposite polarity can be used in a small amount as a developability improver.

Further, when the negatively chargeable toner used in the first invention of the present invention is used as a two-component developer, it is used by mixing with a carrier powder. In this case, the mixing ratio of the toner and the carrier powder is 0.1 to
50 mass%, preferably 0.5 to 10 mass%, more preferably 3 to 5 mass%. As the carrier that can be used at this time, conventionally known carriers can be used. And those treated with a vinyl resin or a silicone resin.

To prepare the negatively chargeable toner used in the first invention of the present invention, a binder resin, a pigment or dye as a colorant, or a magnetic material, if necessary, a release agent, The forming material comprising the control agent and other additives is sufficiently mixed by a mixer such as a Henschel mixer or a ball mixer, and then melted using a hot kneader such as a heating roll, a kneader or an extruder, and the resins are melted. A kneaded product in which a pigment, a dye, a magnetic material, a release agent, and the like are dispersed or dissolved in the mutually compatible components is cooled and solidified, and then pulverized and classified to obtain toner particles having a specific particle size. Further, if necessary, desired additives are sufficiently mixed by a mixer such as a Henschel mixer and externally added.

(Second Invention) Next, the positively chargeable toner used in the second invention of the present invention will be described. The second invention of the present invention is directed to a second aspect of the present invention, wherein the weight average particle diameter containing at least a binder resin and a colorant, or a binder resin and a magnetic material is 4 to 11 μm.
m toner particles have a BET specific surface area of 30 to 50 m ² /
g of a fluidizing agent and a powdered metal oxide having a weight average particle diameter of 0.4 to 5.5 μm are used. Further, among these, when the standard deviation of the number distribution is S _n and the length average particle diameter (μm) based on the number is D _{1 in the} particle size distribution of the toner, the number distribution variation coefficient A expressed by the following equation Is preferably 40% or less. A = S _n / D ₁ × 100

In the positively chargeable toner used in the second invention of the present invention, toner particles having a weight average particle diameter of 4 to 11 μm are used. That is, when the weight average particle size exceeds 11 μm, adverse effects such as a reduction in image resolution and a decrease in density during continuous copying are likely to occur. When the weight average particle diameter of the toner is less than 4 μm, it is difficult to control the charge amount of the toner.

When the value of the number distribution variation coefficient A exceeds 40%, particles larger or smaller than the average particle size are present. Agglomeration between toner particles is likely to occur, resulting in a toner mass having a larger particle size than the original toner, causing adverse effects such as inhibition of charging and deterioration of image quality.
Further, in the case of a toner having a particle size distribution in which the value of the number distribution variation coefficient A exceeds 40% regardless of magnetic / non-magnetic,
The charge balance of the toner particles is lost, and a small-sized toner having an excessive charge is easily charged and adhered to the developing sleeve (and further to the carrier surface in the case of a two-component system). When the toner is not sufficiently supported or charged, or the toner layer having a large particle diameter, which is insufficiently charged, covers the toner layer, developability is reduced, and fog is deteriorated and image density is reduced. Here, the particle size distribution can be measured by various methods, but in the second invention, the measurement was carried out using the above-mentioned Coulter counter as in the first invention.

Next, the binder resin constituting the positively chargeable toner used in the second invention of the present invention will be described. Examples of the binder resin of the positively chargeable toner used in the second invention of the present invention include a vinyl resin, a polyester resin, a polyurethane resin, an epoxy resin, and a phenol resin. Resins and polyester resins are preferred.

Examples of comonomers for obtaining a vinyl resin which can be used in this case include the following. For example, styrene, o-methylstyrene, m
-Methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene,
2,4-dimethylstyrene, pn-butylstyrene,
Styrene such as p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene and derivatives thereof; ethylene, Ethylene unsaturated monoolefins such as propylene, butylene and isobutylene; unsaturated polyenes such as butadiene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; vinyl acetate, vinyl propionate;
Vinyl esters such as benzoic acid; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate ,
Α-methylene aliphatic monocarboxylic esters such as phenyl methacrylate, dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, acryl Acid n-
Acrylic esters such as octyl, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate and phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; vinyl methyl Vinyl ketones such as ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole,
N-vinyl compounds such as N-vinylpyrrolidone; vinylnaphthalenes; acrylonitrile, methacrylonitrile,
Vinylic monomers such as acrylic acid or methacrylic acid derivatives such as acrylamide; and these may be used alone or in combination of two or more. Among these, a combination of monomers that results in a styrene copolymer or a styrene / acrylic copolymer is preferred.

As the crosslinkable monomer, a monomer having two or more polymerizable double bonds is mainly used. The vinyl polymer which can be used for the binder resin in the second invention of the present invention is a polymer cross-linked with a cross-linkable monomer as exemplified below in order to achieve the object of the present invention. Is preferred.

Examples of the monomer having two or more polymerizable double bonds include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; diacrylate compounds linked by an alkyl chain such as ethylene glycol diacrylate. 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6
Hexanediol diacrylate, neopentyl glycol diacrylate, and methacrylates instead of these compounds; diacrylate compounds linked by an alkyl chain containing an ether bond, for example, diethylene glycol diacrylate, triethylene glycol Diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400
Diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate,
And acrylates of these compounds in place of methacrylates; diacrylate compounds linked by a chain containing aromatic and ether bonds, for example, polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) )
Propane diacrylate, polyoxyethylene (4)-
2,2-bis (4-hydroxyphenyl), propane diacrylate, and those obtained by replacing acrylates of these compounds with methacrylates; further, polyester-type diacrylate compounds, for example, trade name MANDA
(Nippon Kayaku) and the like. Among the above crosslinkable monomers, those preferably used in the binder resin for toner include, for example, aromatic divinyl compounds, particularly, divinylbenzene, aromatic groups and ethers, from the viewpoint of fixing property and offset resistance. Examples include diacrylate compounds linked by a chain containing a bond.

Examples of the polyfunctional crosslinking agent used for crosslinking these crosslinking monomers include pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, and oligoester. Acrylates and those obtained by replacing acrylates of these compounds with methacrylates; triallyl cyanurate, triallyl trimellitate; and the like. These cross-linking agents contain 100% by mass of other monomer components.
About 0.01 to 5% by mass, preferably 0.0
It is preferable to use about 3 to 3% by mass.

The polyester resin which can be used as the binder resin of the positively chargeable toner used in the second invention of the present invention is a polyester resin comprising a polycondensate of a polybasic acid component and a polyhydric alcohol component. preferable. First, as the dihydric alcohol component, for example, ethylene glycol, propylene glycol, 1,3-butanediol,
1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5
-Pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, bisphenol represented by the following formula (A) and its derivative, and the following formula (B)
And the like.

[0086] (In the formula (A), R is an ethylene or propylene group,
x and y are each an integer of 0 or more, and the average value of x + y is 0 to 10. )

[0087]

Examples of the divalent acid component to be polycondensed with the above-mentioned dihydric alcohol component include benzenedicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid and phthalic anhydride or anhydrides thereof, and lower alkyls. Esters; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid or anhydrides thereof, lower alkyl esters; alkenyl succinic acids or alkyl succinic acids such as n-dodecenyl succinic acid, n-dodecyl succinic acid, or acids thereof And unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid and itaconic acid, and dicarboxylic acids such as anhydrides and lower alkyl esters, and derivatives thereof.

When the above-mentioned dihydric alcohol component is subjected to polycondensation with a dihydric acid component as described above, a trihydric or higher alcohol component and a trihydric or higher acid component which also serve as crosslinking components described below are used. Can be used together. Examples of the trihydric or higher polyhydric alcohol component include sorbitol, 1,
2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol,
Tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,
Examples include trihydric or higher polyhydric alcohols such as 2,4-butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5-trihydroxybenzene.

Examples of the trivalent or higher polycarboxylic acid component include trimellitic acid, pyromellitic acid,
2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid,
2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8- Polyhydric carboxylic acids such as captan tetracarboxylic acid, empole trimer acid, their anhydrides, lower alkyl esters, tetracarboxylic acids represented by the following formula (C), and their anhydrides, lower alkyl esters; And derivatives thereof.

[0091] (In the formula (C), X represents an alkylene group or alkenylene group having 5 to 30 carbon atoms having at least one side chain having 3 or more carbon atoms.)

Further, the binder resin of the positively chargeable toner used in the second invention of the present invention has an alcohol component of 4%.
0 to 60 mol%, preferably 45 to 55 mol%, and the acid component is 60 to 40 mol%, preferably 55 to 45 mol%.
It is desirable to use 1% polyester resin.
In addition, the trivalent or higher polyvalent component accounts for 5 to 60 mol of all components.
% Is desirable.

In particular, a preferred polyester resin used as a binder resin in the second invention of the present invention uses, as an alcohol component, for example, a bisphenol derivative represented by the above formula (A), and as an acid component, for example, ,
Phthalic acid, terephthalic acid, isophthalic acid or anhydride; succinic acid, n-dodecenyl succinic acid or anhydride, fumaric acid, maleic acid, dicarboxylic acids such as maleic anhydride, trimellitic acid or tricarboxylic acids of anhydride; The polyester resin obtained by use is mentioned. That is, the polyester resin obtained from the acid component and the alcohol component as described above exhibits sharp melting characteristics, and further, the toner using the polyester resin having such a configuration as a binder resin is used for fixing with a heat roller. This is because when the toner is used, the fixability is good and the offset resistance is excellent.

Further, among the polyester resins obtained from the above components, those which are suitable as the binder resin for the toner used in the image forming method of the present invention have a glass transition temperature of 50 to 75 ° C., preferably Is 55 to 65 ° C., and the number average molecular weight Mn is 1,500 to 50,000.
0, preferably 2,000 to 7,000, and a weight average molecular weight Mw of 6,000 to 200,000, preferably 1
Preferred are resins from 000 to 150,000.

In the positively chargeable toner used in the second invention of the present invention, a charge control agent is blended (internally added) to the toner particles in order to enable optimal charge control according to the development system, or It is preferable that the toner particles are mixed (externally added) with the toner particles. In particular, in the second invention of the present invention, by adding a charge control agent to the toner, it becomes possible to control the optimal charge amount according to the development system, and to further stabilize the balance between the particle size distribution and the charge. Becomes possible.

The positive charge control agent used at this time includes:
For example, denatured products such as nigrosine and fatty acid metal salts;
Tributylbenzylammonium-1-hydroxy-4
-Quaternary ammonium salts such as naphthosulfonate and tetrabutylammonium tetrafluoroborate; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide and dicyclohexyltin oxide; dibutyltin borate and dioctyltin borate;
Diorganotin borates such as dicyclohexyl tin borate; and the like, and these can be used alone or in combination of two or more. Among these, charge control agents such as nigrosine compounds and organic quaternary ammonium salts are particularly preferably used.

Further, a monomer of a monomer represented by the following general formula; or a copolymer with a polymerizable monomer such as styrene, acrylate or methacrylate as described above may be used as a positive charge control agent. it can. [In the above formula, R ₁ represents H or CH ₃ , and R ₂ and R ₃ each represent a substituted or unsubstituted alkyl group (preferably, C _1-
Represents C ₄ ). In this case, these positive charge control agents also have an action as a binder resin (all or part).

The charge control agent as described above is preferably used in the form of fine particles. In this case, the number average particle diameter of the charge control agent is specifically 4 μm or less, more preferably 3 μm or less. It is preferable to use When internally added to the toner, the charge control agent as described above is used in an amount of 0.1 to 20 parts by mass based on 100 parts by mass of the binder resin.
It is preferable to use it in the range of parts by mass, more preferably in the range of 0.2 to 10 parts by mass.

In the image forming method according to the second aspect of the present invention, when a positively chargeable magnetic toner is used as a developer, a magnetic material is used in the toner. The following are used.
For example, iron oxides such as magnetite, maghemite, ferrite, and iron oxides containing other metal oxides; Fe, C
metals such as o and Ni, or these metals and Al and C
o, Cu, Pb, Mg, Ni, Sn, Zn, Sb, B
Examples thereof include alloys with metals such as e, Bi, Cd, Ca, Mn, Se, Ti, W, and V, and mixtures thereof. As a specific magnetic material, conventionally, triiron tetroxide (F
e ₃ O ₄ ), iron sesquioxide (γ-Fe ₂ O ₃ ), zinc iron oxide (ZnFe ₂ O ₄ ), yttrium iron oxide (Y ₃ Fe
₅ O ₁₂ ), cadmium iron oxide (CdFe ₂ O ₄ ), gadolinium iron oxide (Gd ₃ Fe ₅ O ₁₂ ), copper iron oxide (CuFe
₂ O ₄ ) lead iron oxide (PbFe ₁₂ O ₁₉ ), nickel iron oxide (NiFe ₂ O ₄ ), neodymium iron oxide (NdFe ₂ O ₃ ),
Barium iron oxide (BaFe ₁₂ O ₁₉ ), iron magnesium oxide (MgFe ₂ O ₄ ), iron manganese oxide (MnFe
₂ O ₄ ), iron oxide lanthanum (LaFeO ₃ ), iron powder (F
e), cobalt powder (Co), nickel powder (Ni) and the like are known. Good. Particularly preferred magnetic materials for the purpose of the second invention of the present invention are fine powders of triiron tetroxide or γ-iron sesquioxide.

These ferromagnetic materials used in the present invention have an average particle size of about 0.1 to 2 μm,
8 kA / m magnetic properties of (10 kilo-oersted) applied, the coercive force (H _c) 1.6~16kA / m, saturation magnetization ^{_{(σ s) 50~200Am 2 / kg}} , a residual magnetization (sigma _r) 2
It is preferred for ~20Am ² / kg. The content of the magnetic material is 10 to 200 parts by mass, preferably 20 to 150 parts by mass, based on 100 parts by mass of the binder resin. These magnetic materials also act as colorants.

The positively chargeable toner used in the second invention of the present invention may contain any suitable pigment or dye other than the magnetic material as in the case of the negatively chargeable toner used in the first invention. Can be used. Examples of the pigment used at this time include, for example, carbon black, aniline black, acetylene black, naphthol yellow, hansa yellow, rhodamine lake, alizarin lake, bengara,
Phthalocyanine blue and indanthrene blue are mentioned. These pigments are preferably used in an amount of 0.1 to 20 parts by mass, more preferably 1 to 10 parts by mass, based on 100 parts by mass of the resin. Examples of the dye include, for example, an azo dye, an anthraquinone dye, a xanthene dye, a methine dye, and the like. It may be used in the range of 3 to 10 parts by mass.

In the case of the positively chargeable toner used in the second invention of the present invention, one or two kinds of toners may be used, if necessary, similarly to the negatively chargeable toner used in the first invention described above. The above release agent may be contained in the toner. Examples of the release agent include the following. For example, aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, and paraffin wax, and oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax, or block copolymers thereof Carnauba wax, sasol wax,
Examples thereof include waxes mainly containing a fatty acid ester such as montanic acid ester wax, and those obtained by partially or entirely deoxidizing fatty acid esters such as deoxidized carnauba wax.

Further, saturated straight-chain fatty acids such as palmitic acid, stearic acid and montanic acid, unsaturated fatty acids such as brandic acid, eleostearic acid and barinaric acid, stearyl alcohol, aralkyl alcohol, behenyl alcohol and carnaubyl alcohol , Seryl alcohol,
Saturated alcohols such as melisyl alcohol, polyhydric alcohols such as sorbitol, fatty acid amides such as linoleic acid amide, oleic acid amide, lauric acid amide, methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid Amide, saturated fatty acid bisamides such as hexamethylenebisstearic acid amide, ethylenebisoleic acid amide, hexamethylenebisoleic acid amide, N, N'-dioleyladipamide, N, N'-dioleylsebacic acid amide Fatty acid amides, aromatic bisamides such as m-xylene bisstearic acid amide, N, N'-distearylisophthalic acid amide, and fatty acid metals such as calcium stearate, calcium laurate, zinc stearate and magnesium stearate (Commonly called metal soap), waxes obtained by grafting aliphatic hydrocarbon waxes with vinyl monomers such as styrene and acrylic acid, and fatty acids such as monoglycerin behenate. Examples thereof include a partially esterified product of a polyhydric alcohol and a methyl ester compound having a hydroxy group obtained by hydrogenation of a vegetable oil or the like.

The amount of the above-mentioned release agent to be added to the toner is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass per 100 parts by mass of the binder resin. As a method for incorporating these release agents into the toner, usually, a binder resin is dissolved in a solvent, the temperature of the resin solution is increased, and the release agent is added and mixed therein while stirring. The binder resin can be contained in the binder resin by a method or a method of mixing the above-mentioned release agent at the time of kneading the forming material when producing the toner.

In the second invention of the present invention, a positively chargeable toner to which a specific fluidizing agent described below is added is used. That is, a toner containing a fine powder having a specific surface area of 30 to 500 m ² / g, preferably 50 to 400 m ² / g as measured by the BET method as a fluidizing agent is used. This is because the specific surface area of the fluidizing agent is 30 m ^2.
/ G or less, the particle size becomes too large, and it becomes difficult to uniformly disperse these fluidizing agents on the toner surface. On the other hand, when the specific surface area of the fluidizing agent is 500 m ² / g or more, This is because electrostatic agglomeration between the fluidizing agents is likely to occur, and “lumps” are likely to occur.

As the fluidizing agent used at this time, it is preferable to use inorganic compound fine powder. Specifically, for example, Group 3 and Group 4 metal oxides such as silicic acid, alumina, and titanium oxide are preferable. In particular, it is preferable to use dry silica fine powder generated by the gas phase oxidation of a silicon halide. Further, during the production of the dry silica fine powder, a composite fine powder of silica and a metal oxide may be used by subjecting it to gas phase oxidation together with another metal halide such as aluminum chloride and titanium chloride.

Further, as the silica fine powder used in the above, not only so-called dry method or fumed silica produced by vapor phase oxidation of a silicon halide, but also water glass or the like can be used. Both so-called wet silicas can be used, but dry silicas having few silanol groups on the surface and inside and having no production residue are preferable. Further, it is preferable that the above silica fine powder has been subjected to a hydrophobic treatment. When the silica fine powder is subjected to a hydrophobic treatment, for example, it may be chemically treated with an organic silicon compound or the like which reacts or physically adsorbs with the silica fine powder. As a preferable method for hydrophobizing silica fine powder, for example, after treating dry silica fine powder generated by gas phase oxidation of silicon halide compound with a silane coupling agent, or simultaneously with treating with a silane coupling agent, A method of treating with an organosilicon compound such as oil or silicone varnish may be used.

The silicone oil used in this case is preferably represented by the following general formula.

[0109] (In the above formula, R represents an alkyl group having 1 to 3 carbon atoms,
R ′ represents a silicone oil-modified group such as alkyl, halogen-modified alkyl, phenyl and modified phenyl;
Represents an alkyl group or an alkoxy group having 1 to 3 carbon atoms. Specific examples thereof include dimethyl silicone oil, alkyl-modified silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl silicone oil, and fluorine-modified siliconoyl. . Of course, the second invention of the present invention is not limited only to the above silicone oil.

It is preferable to use a silicone oil having a viscosity at 25 ° C. of 50 to 1,000 mm ² / S. That is, if it is less than 50 mm ² / S,
When heat is applied, a portion thereof is volatilized, and the charging characteristics tend to deteriorate. On the other hand, when the viscosity at 25 ° C. is 1,0
If it exceeds 00 mm ² / S, handling tends to be difficult due to the processing operation. As a method of treating the silicone oil, a conventionally known technique can be used. For example, a method of mixing fine powder and silicone oil using a mixer, a method of spraying silicone oil into fine powder using a sprayer, a method of dissolving silicone oil in a solvent and then mixing the fine powder, etc. Is mentioned. Of course, the present invention
It is not limited to these methods.

As the silicone varnish used for treating the silica fine powder, known substances can be used. Specifically, for example, KR-251, KP manufactured by Shin-Etsu Silicone Co., Ltd.
-112 and the like, but are not limited thereto. In addition, as a method of the silicone varnish treatment, a known technique can be used similarly to the above-described silicone oil treatment.

Further, as the silicone oil for treating the silica fine powder which can be used in the second invention of the present invention, an amino-modified silicone oil having a structure represented by the following formula can also be used.

[0113] (In the above formula, R ₁ and R ₆ each represent hydrogen, an alkyl group, an aryl group or an alkoxy group, R ₂ represents an alkylene group or a phenylene group, and R ₃ represents a compound having a nitrogen-containing heterocyclic ring in its structure. Wherein R ₄ and R ₅ are each hydrogen,
Represents an alkyl group or an aryl group. Also, R ₂ need not be present. However, the above alkyl group, aryl group, alkylene group, phenylene group may contain an amine,
It may have a substituent such as halogen as long as the conductivity is not impaired. M is an integer of 1 or more, and n and p
Is a positive integer containing 0 each. Here, n + p is a positive integer of 1 or more. )

Among the above structures, the most preferred structure is one in which the number of nitrogen atoms in the side chain containing a nitrogen atom is one or two. Examples of the nitrogen-containing unsaturated heterocycle are shown below.

Examples of the nitrogen-containing saturated heterocycle are shown below. However, the second invention of the present invention is not limited to the above compound examples, but preferably has a 5-membered or 6-membered heterocyclic ring.

As the derivatives, a hydrocarbon group, a halogen group, an amino group, a vinyl group, a mercapto group,
Derivatives into which a methacryl group, a glycidoxy group, a ureido group, etc. are introduced are exemplified.

The amino-modified silicone oil used in the second invention of the present invention preferably has a nitrogen atom equivalent of 10,000 or less, more preferably 300 to 6,000. The nitrogen atom equivalent here means one nitrogen atom
It is a value obtained by dividing the molecular weight by the number of nitrogen atoms per molecule by the equivalent weight per unit (g / eqiv). These may be used alone or in a mixture of two or more. Examples of the silicone varnish used to obtain an amino-modified silicone varnish for fine powder treatment used in the second invention include, for example,
Methyl silicone varnish, phenyl methyl silicone varnish and the like can be mentioned. Among them, methyl silicone varnish is particularly preferable.

The methyl silicone varnish mentioned here is
It is a polymer composed of T ³¹ units, D ³¹ units, and M ³¹ units represented by the following structural formula, and a three-dimensional polymer containing a large amount of T ³¹ units.

[0119]

The methyl silicone varnish or the phenylmethyl silicone varnish is, for example, a substance having a chemical structure represented by the following structural formula. (In the above formula, R ³¹ represents a methyl group or a phenyl group.)

In the above silicone varnish, especially T ³¹
Units imparts good thermal curability, an effective unit for a three-dimensional network structure, thus, the silica fine body whose surface has been treated with a silicone varnish containing such T ³¹ units, on the surface It has a hard and tough coating, and therefore has excellent impact resistance, moisture resistance, and release properties. The T ³¹ unit, 10 in a silicone varnish
It is preferably contained in a proportion of 90 mol%, particularly 30 to 80 mol%. When the proportion of the T ³¹ unit in the silicone varnish is too small, the silicone varnish is increased sticky to soften might moisture resistance, durability, stability of triboelectric chargeability decreases, especially in the toner The cleaning property is reduced, and toner scattering occurs. As a result, image unevenness, fogging and the like are generated, and further, the durability of the fixing device may be reduced. On the other hand, when the proportion of the T ³¹ unit is too large, the coating layer formed on the surface of the inorganic fine particles of the silica fine particles and the like becomes uneven, triboelectric chargeability of stability, durability may decrease.

The above-described silicone varnish has a hydroxyl group at a terminal or a side chain of a molecular chain, and is cured by dehydration condensation of the hydroxyl group. Examples of curing accelerators that can be used to accelerate the curing reaction include fatty acid salts such as zinc, lead, cobalt, and tin; amines such as triethanolamine and butylamine; and the like. Among them, particularly, amines can be suitably used in the present invention.

In order to make the above-mentioned silicone varnish into an amino-modified silicone varnish, the above-mentioned T ³¹ unit, D ³¹
Some of the methyl group or a phenyl group present in the unit and M ³¹ unit may be replaced with a group having an amino group. Examples of the group having an amino group include, but are not limited to, those represented by the following structural formula.

[0124]

As a method for treating silica fine particles and the like with an amino-modified silicone varnish, known techniques can be used in the same manner as in the case of oil treatment. The processing amount of amino-modified silicone oil or amino-modified silicone varnish solids is
The amount is preferably 1 to 35 parts by mass, more preferably 2 to 30 parts by mass, per 100 parts by mass of the silica fine powder. A fluidizing agent such as silica fine powder treated with silicone oil or silicone varnish as described above exhibits an effect when added in an amount of 0.1 to 1.6 parts by mass with respect to 100 parts by mass of the toner. Preferably, it has excellent stability when added in an amount of 0.3 to 1.6 parts by mass. If the amount is less than 0.1 part by mass, the effect of the addition is too small. If the amount exceeds 1.6 parts by mass, problems tend to occur during development and fixing.

In particular, as a fluidizing agent such as silica fine powder to be contained in the positively chargeable toner used in the second invention of the present invention (hereinafter, silica fine powder will be described as a representative example), silane It is preferable to use a material that has been treated with a coupling agent and then treated with silicone oil or silicone varnish (hereinafter, a case of treatment with silicone oil will be described as a typical example). That is, generally, only with silicone oil treatment, the amount of silicone oil for covering the surface of the silica fine powder or the like becomes large, and the aggregate of the fine powder is easily formed during the treatment,
When applied to a developer, the fluidity of the developer may be deteriorated. Therefore, it is necessary to pay sufficient attention to the process of treating silicone oil. However, in order to remove agglomerates of the silica fine powder while maintaining good moisture resistance, after treating the silica fine powder with a silane coupling agent, the silicone oil It is preferred to treat with. In this case, the effect of the hydrophobic treatment by the silicone oil on the silica fine powder can be sufficiently exhibited.

The silane coupling agent used in this case is preferably represented by the following general formula. R _m SiY _n (wherein, R represents an alkoxy group or a chlorine atom,
m represents an integer of 1 to 3, Y represents a hydrocarbon group containing an alkyl group, a vinyl group, a glycidoxy group or a methacryl group, and n represents an integer of 3 to 1. Specifically, for example, dimethyldichlorosilane, trimethylchlorosilane, allyldimethylchlorosilane, hexamethyldisilazane, allylphenyldichlorosilane, benzyldimethylchlorosilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane , Vinyltriacetoxysilane, divinylchlorosilane, and dimethylvinylchlorosilane.

The method for treating the silica fine powder with a silane coupling agent may be a dry treatment in which a vaporized silane coupling agent is reacted with a cloud of silica fine powder by stirring or the like, or a method in which the silica fine powder is dissolved in a solvent. It can be treated by a method such as a wet method in which the silane coupling agent is dispersed and dispersed therein in a dropwise manner. The treatment with the silane coupling agent is performed in the range of 1 to 100 parts by mass of the silica fine powder.
The treatment may be carried out at 50 parts by mass, more preferably 5 to 40 parts by mass.

The amount of the silicone oil or silicone varnish solidified as a fluidizing agent to be added to the positively chargeable toner used in the second invention of the present invention is 1 to 35 parts by mass with respect to 100 parts by mass of the silica fine powder. And more preferably 2 to 30 parts by mass. The reason for limiting the processing amount is
If the silicone oil treatment amount is too small, the result will be the same as when treated only with the silane coupling agent, the moisture resistance will not be improved, and the silica fine powder will absorb moisture under high humidity, and a high quality copy image will be obtained. Can not be. On the other hand, if the silicone oil treatment amount is too large, the above-mentioned aggregate of silica fine powder is likely to be formed, and severely, free silicone oil is formed. The problem that the function is not sufficiently exhibited tends to occur.

Further, the positively chargeable toner used in the second invention of the present invention is characterized in that a metal oxide having a weight average particle diameter of 0.4 to 5.5 μm is added. Thus, unlike the conventional method of lowering the charge amount of the toner by adding conductive powder or the like, the charge amount of the toner having a lower charge amount in the charge amount distribution is increased by the contact between the toner and the metal oxide. It is possible. That is, in the second aspect of the present invention, a uniformly charged toner is obtained by contact friction charging of the toner and the metal oxide, and this is used in the image forming method.

In this case, the weight average particle size is 0.4 to 5.5.
A μm metal oxide powder is used. If the thickness is 0.4 μm or less, there may be a case where cleaning failure due to slippage by the cleaning blade or occurrence of charging inhibition due to remaining on the latent image carrier may occur.
If it is larger, it will not be developed in the inverted portion of the white background, and will not be consumed, but will accumulate in the developing device, and the amount of metal oxide powder on the developer carrier will increase, which may cause the copy image quality to gradually decrease. Because there is. The particle size distribution of the metal oxide powder was measured by the same method as the toner particle size distribution measuring method, except that the aperture diameter was changed to 13 μm.

The metal oxides used in the second invention of the present invention include the following. For example, oxides of alkaline earth metals, rare earth metals, transition metals, etc., specifically, oxide fine particles of alkaline earth metals such as barium, magnesium, calcium, strontium; yttrium, eurobium, cerium, lanthanum rare earth Metal oxide fine particles; scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper,
Oxide fine particles of a transition metal such as zinc may be used.

The metal oxide fine particles used in the second invention of the present invention may be the following composite metal oxide fine particles.
Particularly preferable results are obtained by using such a composite metal oxide. As the composite metal oxide, for example, TiO
_{2 -SrO, TiO 2 -MgO, TiO} 2 -BaO, Ti
_{O 2 -CaO, TiO 2 -MgO-} NiO, TiO 2 -S
_{rO-NiO, TiO 2 -CaO-} NiO, CuO-C
_{r 2 O 3, CoO-Al} 2 O 3, CuO-Fe 2 O 3 -Mn 2
O _{3 and the} like. Among them, it is particularly preferable to use a composite metal oxide represented by the following formula (1) or (2).

[M] _a [Ti] _b O _c (1) (where M is Sr, Mg, Zn, Co, Mn and C
e represents a metal element selected from the group consisting of
Represents an integer of 9, c represents an integer of 3 to 9) [M1] and _{a [Si] b O c,} [M2] b [Ti] combination with _e O _f ··· (2) ( In the above formula, M1 and M2 are Sr, Mg, Zn, and C, respectively.
o, represents a metal element selected from Mn and Ce, a,
b, d and e each represent an integer from 1 to 9, and c and f each represent an integer from 3 to 9)

The present inventor has conducted various studies on the fact that excellent effects can be obtained when the above-described composite metal oxide is used, and as a result, the following has been found. First, when a complex oxide containing a Ti element as shown in (1) is added, not only can the charge amount be made uniform by contact friction with the toner, but also the latent image carrier It is also effective for removing the deposits on
It has been found that there is an excellent effect that the surface of the latent image carrier is not damaged even in continuous copying. In contrast,
In particular, under high temperature and high humidity, there is a problem that the growth of deposits on the latent image carrier is remarkable, and problems such as image deletion and fogging are likely to occur during continuous copying. Addition is required. In this sense, it is effective to add a composite oxide containing a Ti element among the above composite metal oxides.

As described above, in the positively chargeable toner used in the second invention of the present invention, a toner to which a fluidizing agent such as silica fine powder is added is used. The addition achieves an improvement in fluidization of the toner and also enhances the developability. This is because the fluidizing agent has polarity and also affects the charging characteristics of the toner. However, when the amount of the fluidizing agent added is excessive, the degree of adhesion to the toner surface varies, and it becomes difficult to uniformly charge the individual toner particles. Therefore, it is not preferable to increase the amount of the fluidizing agent added to the toner. On the other hand, when the metal oxide is added in the form of a complex oxide, the fluidity of the complex oxide itself can be improved by mixing a fluidizing agent before adding the complex oxide to the toner. Becomes possible. Further, by using the composite oxide, it is possible to prevent the fluidity of the toner from decreasing under high temperature and high humidity. However, in this case, the charge imparting ability itself due to contact frictional charging with the toner, which is the original purpose of adding the composite oxide, is reduced,
It was found that adverse effects such as a decrease in density and fog occurred. This is because, when the toner is in the above-described mode, in addition to the contact triboelectric charge that originally occurs between the toner and the composite oxide,
It is considered that the transfer of charge between the fluidizing agent and the composite oxide occurs, thereby reducing the charge amount of the entire toner.

In view of the above, the present inventor
Metal oxide is used as an additive to impart the polishing effect to the toner and to achieve the purpose of obtaining a uniform and high charge amount of the toner by frictional contact with the toner without damaging the fluidity of the toner. As a result of various investigations on the compound, particularly the composite oxide, the following was found. A method of increasing the charge amount by contact between the toner and the composite oxide, that is, instead of controlling the charge amount of the toner by adhering the composite oxide to the toner, the contact friction between the toner and the composite oxide in the developing device is increased. In the charging method, Ti
It has been found that the use of the composite oxide containing the compound enables the toner to have a function of polishing the deposits on the latent image bearing member and realize a toner having a uniform and high charge amount. Furthermore,
It has been found that by using a composite oxide containing Si as shown in the formula (2), a toner having a high charge amount can be realized while improving the fluidity of the toner. From the above,
Even in a high-temperature and high-humidity environment where the growth of the deposits on the latent image carrier is remarkable, the deposits on the drum can be easily removed, and the deterioration in image quality that occurs during continuous copying is prevented, and a high image density can be obtained. The structure of a positively chargeable toner capable of exhibiting excellent effects has been found.

That is, by using a compound oxide containing a Ti element, a polishing function can be imparted to the toner, and a toner having a uniform and high charge amount can be realized. In addition to the above, it has been found that by using a mixture containing the Si element used as a fluidizing agent as described above, it is possible to impart fluidity to the toner. Here, in the composite oxide containing the Si element, the Si element exhibits excellent fluidity characteristics, similarly to silica generally used as a fluidizing agent. Also, S
The composite oxide containing the i element has a high charge-imparting ability even in contact frictional charging with the toner, and increases the toner charge amount. For this reason, if a composite oxide containing Si element is added to the toner, the developing property can be sufficiently satisfied even with a small number of times of contact with the toner while preventing the fluidity of the toner from decreasing even under high temperature and high humidity. It is possible to obtain the obtained high charge amount. However, since the polishing effect of such a complex oxide containing a Si element is low and has little effect on removing deposits on a drum, when used alone, the intended purpose of the present invention is not achieved. It was also found that a sufficient effect to achieve all was not obtained.

From the above, as the positively chargeable toner suitable for use in the second invention of the present invention, the influence of, for example, the adhering matter which grows on the latent image carrier, which is likely to occur under high temperature and high humidity, is considered. The toner is described in the formula (1), which has a sufficient polishing effect without damaging the surface of the latent image carrier, and has a uniform and high charge-imparting ability to the toner. Such a Ti-containing composite oxide is used, or as described in Formula (2),
In addition to the Ti-containing composite oxide as in (1), a combination of a Si-containing composite oxide having a higher charge-imparting ability in contact charging to prevent a decrease in toner fluidity caused by water absorption and the like is used simultaneously. Has been found to be particularly effective.

In the Ti-containing composite oxide used at this time, M and M2 in the formula (1) or (2) represent magnesium, zinc, cobalt, manganese, strontium,
Examples thereof include cerium and the like. Among these, it is particularly preferable to use strontium titanate (SrTiO ₃ ) as the Ti-containing composite oxide in order to more effectively exert the effects of the second invention of the present invention.

Examples of the Si-containing composite oxide include those in which M1 in the formula (2) is magnesium, zinc, cobalt, manganese, strontium, cerium, or the like. Among them, strontium silicate (SrSiO ₃ ) is preferably used as the Si-containing composite oxide in order to more effectively exert the effects of the second invention of the present invention. Further, in order to more effectively exert the effect of the second invention of the present invention, the other metal element and Ti in the Ti-containing composite oxide as described above are used.
When the ratio is expressed by the ratio of a to b in the formula (1), it is preferable that a / b = 0.1 to 9.0, more preferably, a / b = 0.5. It is good to use the thing of ~ 3.0. Further, the ratio of Si to the other metal element in the Si-containing composite oxide is expressed by a / b = 0.1 to 9.0 when expressed by the ratio of a to b in the equation (2). Certain ones are preferred, and more preferably those with a / b = 0.5-3.0.

Further, as shown in the equation (2), when the Ti-containing composite oxide and the Si-containing composite oxide are mixed and used, the molar ratio is expressed as Ti-containing composite oxide / Si-containing composite oxide = It is preferably 19.0 to 0.05, more preferably 1.5 to 0.25.

The metal oxide powder comprising the above-mentioned complex oxide to be contained in the positively chargeable toner used in the second invention of the present invention is, for example, produced by a sintering method, What was prepared is to classify the material by air classification so that the weight average particle size becomes 0.4 to 5.5 μm. When the composite oxides are mixed and used in the combination described in the formula (2), it is preferable to mix them at the production stage in the sintering method. The content of the metal oxide powder composed of these composite oxides is 0.05 to 1 with respect to 100 parts by mass of the toner particles.
It is preferable to use 5 parts by mass, preferably about 0.1 to 7.0 parts by mass.

As other additives contained in the positively chargeable toner used in the second invention of the present invention, for example, lubricants such as Teflon, zinc stearate, and polyvinylidene fluoride are preferable, and polyvinylidene fluoride is particularly preferable. In addition, a small amount of an anti-caking agent, white fine particles and black fine particles of opposite polarity can be used as a developing property improver.

Further, when the positively chargeable toner having the above structure is used as a two-component developer, it is used by mixing with a carrier powder. In this case, the mixing ratio of the toner and the carrier powder is such that the toner concentration is 0.1 to 50% by mass, preferably 0.5 to 10% by mass, and more preferably 3 to 10% by mass.
It is desirably set to 〜5% by mass. As the carrier that can be used at this time, any of conventionally known carriers can be used.For example, iron powder, ferrite powder, magnetic powder such as nickel powder, glass beads, and the like and their surfaces are used. Those treated with a fluorine-based resin, a vinyl-based resin, a silicon-based resin, or the like can be given.

To prepare the positively chargeable toner used in the second invention of the present invention, first, a binder resin, a pigment or dye as a colorant, or a magnetic material, and if necessary, The charge control agent, release agent, and other additives are thoroughly mixed by a mixer such as a Henschel mixer or a ball mixer, and then melted using a hot kneader such as a heating roll, a kneader, or an extruder. The releasing agent, the pigment, the dye, and the magnetic substance are dispersed or dissolved while the components are mutually compatible, and the melt is cooled and solidified, and then pulverized and classified to obtain toner particles. Next, the obtained toner particles are sufficiently mixed with a fluidizing agent, a specific metal oxide powder, and, if necessary, a desired additive by a mixer such as a Henschel mixer, to thereby obtain a toner according to the present invention. What is necessary is just to obtain a positively chargeable toner used in the second invention.

[0147]

The present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples. All parts in the following formulations are parts by mass unless otherwise specified. First, a negatively chargeable toner and a developer carrying member used in Examples and Comparative Examples of the first invention of the present invention were prepared, and an image was formed using these. Table 1 shows a list of the negatively chargeable toner and the developer carrier used here.

[First Invention] <Production Example of Toner 1A> Bisphenol A ethylene oxide adduct 20 mol% Bisphenol A propylene oxide adduct 20 mol% Terephthalic acid 30 mol% Fumaric acid 20 mol% Tri Merritic acid 10 mol% The above material was placed in a four-necked round bottom flask equipped with a thermometer, a stainless steel stirrer, a glass nitrogen inlet tube, and a falling condenser. Next, the flask was placed in a mantle heater, nitrogen gas was introduced from a glass inlet tube to keep the inside of the reactor in an inert atmosphere, and the temperature was raised to 220 to 2
A dehydration condensation reaction was performed at 50 ° C. After completion of the reaction, the mixture was cooled and solidified to obtain a polyester resin. The obtained polyester resin has an acid value of 30 mg KOH / g, a glass transition temperature (Tg) of 60 ° C., and a number average molecular weight Mn of 11,00.
0, the weight average molecular weight Mw was 48,000. Using this polyester resin as a binder resin, a magnetic toner 1A was obtained as described below.

• 100 parts of the above polyester resin • 90 parts of triiron tetroxide (average particle size 0.2 μm, H _c : 9 kA / m, σ _s : 80 Am ² / kg, σ _r : 11 Am ² / kg) • monoazo iron Complex 1 part ・ Low molecular weight propylene-ethylene copolymer 3 parts After well mixing the above materials with a blender mixer,
Kneading was performed by a twin-screw kneading extruder set at 50 ° C. The obtained kneaded material is cooled, coarsely pulverized by a cutter mill, and then finely pulverized using a fine pulverizer using a jet stream, and the obtained finely pulverized material is subjected to a multi-division classifier utilizing the Coanda effect ( The particles were classified by an elbow jet classifier (manufactured by Nippon Steel Mining Co., Ltd.) to obtain a magnetic toner 1A having a weight average particle size of 7.56 μm.

<Production Example of Toner 1B> 75 parts of styrene 12 parts of n-butyl acrylate 10 parts of monobutyl maleate 3 parts of di-tert-butyl peroxide 200 parts of xylene heated to reflux temperature The material was added dropwise over 4 hours. Furthermore, under xylene reflux (13
(8-144 ° C) to complete the polymerization and then under reduced pressure at 200 ° C
The xylene was removed while the temperature was being raised. The resin thus obtained is referred to as resin A.

30 parts of resin A 48 parts of styrene 13 parts of n-butyl acrylate 7 parts of monobutyl maleate 0.5 part of divinylbenzene 1.5 parts of benzoyl peroxide 170 parts of water in which 0.15 part of the partially saponified substance was dissolved was added and stirred to obtain a suspension dispersion. 60 parts of water was added, the suspension dispersion was added to a reaction vessel purged with nitrogen, and a suspension polymerization reaction was performed at a reaction temperature of 80 ° C. for 8 hours. After completion of the reaction, washing with water, dehydration and drying were performed to obtain a vinyl resin. The obtained vinyl resin had an acid value of 28 mgKOH / g, a Tg of 58 ° C., a Mn of 12,500, and a Mw of 190,000. However,
The vinyl resin contains 28% of a gel, and the molecular weight was calculated by removing the gel component. The vinyl resin thus obtained was used as a binder resin to obtain a magnetic toner 1B as described below.

[0152] - the vinyl-based resin 100 parts tri-iron tetroxide (average particle size _{0.2μm, H c: 9KA / m} , σ s: 80Am 2 / kg, σ r: 11Am 2 / kg) 90 parts 3 Chromium complex of 2,5-di-tert-butylsalicylic acid 2 parts Low-molecular-weight propylene-ethylene copolymer 3 parts The above material was converted into a toner by the same method as in Production Example 1 of toner, and the weight average particle diameter was 6%. .95 μm toner was obtained.
The obtained toner was designated as magnetic toner 1B.

<Comparative Production Example of Toner 1D> A vinyl resin was synthesized in the same manner as in Production Example 2 of Toner except that 2-ethylhexyl acrylate was added instead of monobutyl maleate. The obtained resin had an acid value of 0.5 mg KOH / g, a glass transition temperature Tg of 59 ° C.,
Mn was 9,000 and Mw was 100,000.
The gel content was 20%. The toner was converted into a toner in the same manner as in Production Example 2 of the toner to obtain a magnetic toner 1D having a weight average particle diameter of 7.62 μm.

<Comparative Production Example of Toner 1E> In the production example of Toner 1A, magnetic toner 1E having a weight average particle size of 3.85 μm was obtained by changing the pulverization / classification conditions.

<Comparative Production Example of Toner 1F> In the production example of Toner 1B, the weight average particle diameter was 12.5 μm and the variation coefficient was 20.7% by changing the pulverization / classification conditions.
Of magnetic toner 1F was obtained.

<Production Example of Toner 1C> A toner was produced in the same manner as in Production Example of Toner 1A, except that 4 parts of carbon black was added instead of iron sesquioxide in Production Example of Toner 1A. A nonmagnetic toner 1C having an average particle size of 9.2 μm was obtained.

<Production Example of Developing Sleeve 1A> 1 part of conductive carbon (average particle diameter 30 nm) 9 parts of graphite (average particle diameter 10 μm) 9 parts of phenolic resin 65 parts of isopropyl alcohol First, the above-mentioned coating material mixture was mixed. And dispersed at room temperature for 5 minutes using a sand mill. Next, the obtained dispersion was diluted with isopropyl alcohol to a solid content of 20% by mass to form a coating solution, and the surface was blasted with abrasive grains of FGB # 300 to form irregularities with an outer diameter of 20 mmφ. Aluminum magnet sleeve (Magnet roll is GP21
5) was applied in a thickness of 10 μm. Next, the sleeve was placed in a hot-air drying oven, heated at 150 ° C. for 30 minutes, and cured to form a resin film on the magnet sleeve. Further, the surface of the developing sleeve was polished with a wrapping tape and then washed with ethanol to obtain a developing sleeve 1A. The JIS center line average roughness (Ra) of the developing sleeve 1A is 0.7
It was 5 μm.

<Production Example of Developing Sleeve 1B> 1 part of conductive carbon (average particle diameter 25 nm) 9 parts of graphite (average particle diameter 7 μm) 20 parts of polycarbonate resin 70 parts of isopropyl alcohol Example of production of developing sleeve 1A Developing sleeve 1B (20 mmφ) in the same manner as in Developing sleeve production example 1 except that a coating liquid using the above-mentioned coating material mixture was applied onto an aluminum magnet sleeve subjected to the same treatment as in the case.
Was prepared. JIS center line average roughness (Ra) is 0.6
It was 5 μm.

<Production Example of Developing Sleeve 1C> ・ 100 parts of polyamide resin ・ 40 parts of potassium titanate (average particle size: 0.8 μm) ・ 20 parts of carbon black (average particle size: 30 nm) 20 parts: , And formed into pellets, and then a developing sleeve made of resin having an outer diameter of 20 mmφ was formed using a single screw extruder. The outer surface of this developing sleeve is subjected to sand blasting (using FGB # 300), a conductive paint is applied to the inner surface, and then attached to a magnet roll used for a developing sleeve of a Canon copier GP55 to produce a developing sleeve. did. This developing sleeve was polished with wrapping paper and then washed with ethanol to obtain a developing sleeve 1C. The JIS center line average roughness (Ra) was 0.7 μm.

<Comparative Manufacturing Example of Developing Sleeve 1D> A developing sleeve 1D was obtained in the same manner as in the manufacturing example of the developing sleeve 1A, except that the resin layer was not provided on the surface of the developing sleeve 1A. The JIS center average roughness (Ra) was 0.6 μm.

<Comparative Manufacturing Example of Developing Sleeve 1E> In the manufacturing example of the developing sleeve 1A, except that the polishing process was not performed after the resin layer was provided on the surface of the developing sleeve, the same as the manufacturing example of the developing sleeve 1A. A developing sleeve 1E was obtained. The JIS center average roughness (Ra) was 1.8 μm.

<Comparative Manufacturing Example of Developing Sleeve 1F> Further, in the manufacturing process of the developing sleeve 1B, the JIS center line average roughness (Ra) was reduced to 0.1 by strengthening the polishing conditions.
A developing sleeve 1F of μm was obtained.

(Example 1) Magnetic toner 1A (100 parts)
In addition, negatively charged hydrophobically treated silica (BET specific surface area 300
m ² / g) and mixed with a Henschel mixer to obtain a negatively chargeable magnetic toner (developer) 1A. When the negatively-chargeable magnetic toner 1A was measured using a Coulter Multisizer II having an aperture of 100 μm, the weight average particle diameter (D ₄ ) was 7.56 μm, and the variation coefficient A of the number distribution was 27.0%. Met. The measurement was performed as follows.
The calculation was performed within the range of 826 to 63.490 μm, and the statistical calculation was performed using 50,000 toner particles by dividing this range into 256 sections.

This negatively chargeable magnetic toner 1A was converted to a Canon digital copier (GP215 modified with an amorphous silicon drum, with a process speed of 210 m).
m / s), and using the above-mentioned developing sleeve 1A as a developing sleeve, under a normal temperature / normal humidity environment (23 ° C.).
/ 60% RH: N / N) under normal temperature / low humidity environment (23 ° C)
/ 5% RH: N / L) and high temperature / high humidity environment (30 ° C)
/ 80% RH: H / H), an image output test of 100,000 sheets was continuously performed. Note that the image forming apparatus used has a configuration generally shown in FIG. The gap between the latent image carrier and the developing sleeve was set to 180 μm. As the developing bias, a rectangular wave bias shown in FIG. 2 was used as the AC voltage component. The frequency at this time is 1,800 Hz,
The absolute value (peak to peak) of the bias voltage was 800 V, and a DC voltage of -580 V was applied. The potential of the dark portion on the latent image carrier was -720 V, the potential of the bright portion was -160 V, and development was performed by reversal development.
The peripheral speed of the developing sleeve (with respect to the latent image carrier) is 180%
And Image evaluation was performed according to the following evaluation methods and criteria.
Table 2 shows the results. As can be seen from Table 2, good images could be obtained all the time under any environment.

(Evaluation Method and Criteria) Image quality Using a loupe, the character image was comprehensively evaluated for sharpness, scattering, and the like. ○: Excellent △: Possible △ ×: Somewhat problematic ×: Problematic

2. The fog solid image was visually judged. ○: Excellent △: Possible △ ×: Somewhat problematic ×: Problematic

(Example 2) Magnetic toner 1B (100 parts)
In addition, negatively charged hydrophobically treated silica (BET specific surface area 300
m ² / g) and mixed with a Henschel mixer to obtain a negatively-chargeable magnetic toner (developer) 1B. D ₄ of the negatively chargeable magnetic toner. 1B 6.95Myuemu, variation coefficient A was 30.1% (Coulter Multisizer II
use). A digital copier made by Canon equipped with an OPC drum using the negatively chargeable magnetic toner 1B (a machine in which the process speed was set to 180 mm / s by modifying GP215).
The developing sleeve 1B was used as a developing sleeve, and an image output test of 100,000 sheets was continuously performed under the same environment as in Example 1.

Note that the gap between the latent image carrier and the developing sleeve is
It was set to 180 μm. As for the developing bias,
As the AC voltage component, the rectangular wave bias shown in FIG. 3 was used. At this time, the frequency was 2,200 Hz, the absolute value of the bias voltage (Peak to Peak) was 800 V, and -580 V was applied as a DC voltage. The potential of the dark part on the latent image carrier was -680 V, and the potential of the bright part was -2.
The voltage was set to 00 V, and the development was performed by reversal development. Further, the peripheral speed of the developing sleeve (with respect to the latent image carrier) was set to 180%. The same image evaluation as in Example 1 was performed. Table 2 shows the results. As can be seen from Table 2, good images were obtained all the time under any environment. In addition, the density gradation in the photographic image was excellent, and generation of sleeve ghost was not observed throughout.

(Embodiment 3 and Embodiment 4) The same method as in Embodiment 1 was adopted except that the process speed was changed to 250 mm / s (Embodiment 3) and 285 mm / s (Embodiment 4), respectively. Image evaluation was performed. Table 2 shows the results. As can be seen from Table 2, good results were obtained throughout.

(Example 5) Using a negatively chargeable magnetic toner 1B and a developing sleeve 1C, a Canon digital copier GP55 equipped with an OPC drum was modified and put into a machine with a process speed of 200 mm / s. Example 1
Image evaluation was performed in the same manner as described above. The gap between the developing sleeve and the latent image carrier was set to 180 μm. As the developing bias, an asymmetric rectangular wave bias shown in FIG. 4 was used for the AC voltage component. The frequency at this time is 1,850
Hz, the absolute value of the bias voltage (Peak to Peak)
k) was 800 V, and -580 V was applied as a DC voltage. The dark area potential on the latent image carrier is -740.
V, the light portion potential was -260 V, and development was performed by reversal development. The peripheral speed of the developing sleeve (with respect to the latent image carrier) is 1
50%. Table 2 shows the results of image evaluation performed in the same manner as in Example 1. As can be seen from Table 2, good images were obtained all the time under any environment. Furthermore, there was no problem with the density gradation and the sleeve ghost in the photograph mode.

(Example 6) In Example 1, the developing device and the magnet roll were changed to a non-magnetic two-component type. For the developer, non-magnetic toner 1C (100 parts)
Negatively charged hydrophobized silica (BET specific surface area 300m
The ² / g) measured by 0.8 externally added toner (Coulter Multisizer II, D ₄ is 9.2 .mu.m, the variation coefficient A was 22.3) 3 parts, was coated with a fluorine acrylic resin A negatively chargeable nonmagnetic two-component developer 1C comprising 97 parts of a ferrite carrier was used. Using this negatively chargeable nonmagnetic toner 1C, image evaluation was performed in the same manner as in Example 1. Table 2 shows the results. As can be seen from Table 2, good images were obtained throughout.

(Example 7) In the production example of the toner 1A, the conditions of pulverization and classification were changed to obtain the obtained toner powder 1A.
In 00 parts, negatively charged hydrophobized silica (BET specific surface area 2
(00 m ^{2 /} g) and 3 parts of strontium titanate were externally added by a Henschel mixer to obtain a negatively chargeable magnetic toner (developer) 1A ′. This negatively chargeable magnetic toner 1
D ₄ of A 'is 10.0 [mu] m, variation coefficient A was 20.8. Image evaluation was performed in the same manner as in Example 1 using the negatively chargeable magnetic toner 1A ′ and the developing sleeve 1A similar to that in Example 1. As the developing bias, the asymmetric bias shown in FIG. 5 was used. However, the frequency is 2,
500 Hz, absolute value of bias voltage (peck to
peck) was changed to 800V. Note that the duty ratio is 30%. The peripheral speed of the developing sleeve (with respect to the latent image carrier) was set to 150%. Other conditions were performed according to Example 1. Image evaluation was performed in the same manner as in Example 1. Table 2 shows the results. As can be seen from Table 2, good images were obtained throughout.

Comparative Example 1 A negatively chargeable magnetic toner 1D was obtained in the same manner as in Example 1 except that the magnetic toner 1D was used instead of the magnetic toner 1A. The evaluation was performed under the same conditions as in Example 1 except that the negatively chargeable magnetic toner 1D was used. As shown in Table 2, the image evaluation results showed that the developability was particularly poor in a low humidity environment (N / L).

Comparative Example 2 A negatively chargeable magnetic toner 1E was obtained in the same manner as in Example 1 except that the magnetic toner 1A was used instead of the magnetic toner 1A. Evaluation was performed under exactly the same conditions as in Example 1 except that the negatively chargeable magnetic toner 1E was used. As shown in Table 2, as a result of the image evaluation, adverse effects such as uneven toner coating on the developing sleeve and deterioration of fog due to charge-up in a low humidity environment occurred.

Comparative Example 3 A negatively chargeable magnetic toner 1F was obtained in the same manner as in Example 1 except that the magnetic toner 1F was used instead of the magnetic toner 1A. The evaluation was performed under exactly the same conditions as in Example 1 except that the negatively chargeable magnetic toner 1F was used. As a result, as shown in Table 2, the developability (decrease in density, deterioration in image quality, etc.) especially in a high humidity environment was not excellent.

Comparative Example 4 An image was evaluated under the same conditions as in Example 1 except that the developing sleeve 1D was used. As a result, as shown in Table 2, a decrease in developability due to durability was observed under any environment. Also, the level of the sleeve ghost was bad both at the start and during the endurance.

Comparative Example 5 Image evaluation was performed under the same conditions as in Example 1 except that the developing sleeve 1E was used. Table 2 shows the evaluation results. In particular, adverse effects such as a low initial image density in a high humidity environment and deterioration of fog due to durability occurred.

Comparative Example 6 Image evaluation was performed in the same manner as in Example 2 except that the developing sleeve 1F was used. Table 2 shows the evaluation results. There were problems such as a decrease in density under low humidity and unevenness of toner coating on the developing sleeve. Also, the density gradation in the photograph mode was remarkably inferior to Example 2.

Table 1: Toner and developer carrier used in Examples and Comparative Examples

Table 2: Image evaluation results

[Second Invention] Next, the present invention will be described in more detail with reference to Examples and Comparative Examples of the second invention of the present invention. First, a positively-chargeable toner and a developer carrier used in Examples and Comparative Examples of the second invention of the present invention were prepared.
An image was formed using these. Table 3 shows a list of the positively chargeable toner and the developer carrier used here. <Production Example of Toner 2A> 82 parts of styrene 18 parts of n-butyl acrylate 2 parts of di-tert-butyl peroxide First, the above material was heated to reflux temperature in xylene 20.
The mixture was added dropwise to 0 parts over 4 hours. Further, the polymerization was completed under xylene reflux (138 to 144 ° C.),
Xylene was removed while raising the temperature to ° C. The resin thus obtained is referred to as a resin B.

80 parts of styrene 19 parts of n-butyl acrylate 1 part of divinylbenzene 1.5 parts of benzoyl peroxide Next, water 170 obtained by dissolving 0.15 part of partially saponified polyvinyl alcohol in the above material is used. And agitated to obtain a suspension dispersion. 60 parts of water was added, the suspension was added to a reaction vessel purged with nitrogen, and a suspension polymerization reaction was performed at a reaction temperature of 80 ° C. for 8 hours. Resin C obtained by this,
The resin B obtained above was mixed with a solution at a mass ratio of B: C = 70: 30, washed with water, dehydrated, and dried to obtain a vinyl resin.
Tg of the obtained vinyl resin is 59 ° C., Mn is 8,
800 and Mw were 251,000. However, the resin contained a gel content of 25%, and the molecular weight was calculated by removing the gel content.

100 parts of the above vinyl-based resin 90 parts iron trioxide (average particle size 0.2 μm, Hc = 9 kA / m, σs = 80 Am ² / kg, σr = 11 Am ² / kg) 4 parts Nigrosine 3 parts of low molecular weight propylene-ethylene copolymer The above materials were well premixed with a blender mixer, and then kneaded with a biaxial kneading extruder set at 150 ° C. The obtained kneaded material is cooled, coarsely pulverized by a cutter mill, and then finely pulverized using a fine pulverizer using a jet stream, and the obtained finely pulverized material is subjected to a multi-division classifier utilizing the Coanda effect ( Elbow jet classifier manufactured by Nippon Steel Mining)
And magnetic toner 2A was obtained.

<Production Example of Toner 2B> Bisphenol A ethylene oxide adduct 25 mol% Bisphenol A propylene oxide adduct 23 mol% Terephthalic acid 16 mol% Trimellitic anhydride 13 mol% Dodecenyl succinic acid 23 mol% -Dibutyltin oxide 0.03 mol% The above materials were placed in a four-necked round bottom flask equipped with a thermometer, a stainless steel stirrer, a glass nitrogen inlet tube, and a falling condenser. Next, the flask was placed in a mantle heater, and nitrogen gas was introduced from a glass inlet tube to raise the temperature while maintaining the inside of the reactor in an inert atmosphere, and stirring was performed while maintaining the inside of the reactor at 210 to 220 ° C. The reaction was continued. Next, when the distillation of water in the system stopped, the pressure was reduced to 5 mmHg to distill out the dialcohol component. When the load in the system started to increase, 40 mmH
Changing the pressure in the reactor to g slowed the increase in the stirring load. This operation is performed when the pressure in the system is 300 mm.
When the reaction was continued until Hg was reached, almost no distillate component was generated. Thereafter, the pressure was returned to normal pressure, and the mixture was stirred for 1 hour to obtain a polyester resin. The acid value of this polyester resin was 1.2 mgKOH / g, Tg was 60 ° C., Mn was 9,000, and Mw was 45,000.

100 parts of the above polyester resin 90 parts of iron tetroxide (average particle size 0.2 μm, H _c = 9 kA / m, σ _s = 80 Am ² / kg, σ _r = 11 Am ² / kg) Ammonium tetrafluoroborate 2 parts Low molecular weight propylene-ethylene copolymer 4 parts The above materials were converted into a toner in the same manner as in the production example of toner 2A. The obtained toner is referred to as a magnetic toner 2B.

<Comparative Production Example of Toner 2D> In the production example of Toner 2A, magnetic toner 2D having a different particle size and particle size distribution was obtained by changing the pulverization / classification conditions.

<Production Example of Toner 2C> A toner was produced in the same manner as in the production example of Toner 2A except that carbon black was added four times instead of ferric oxide in the production example of Toner 2A. As a result, a magnetic toner 2C was obtained.

<Production Example 1 of Fluidizing Agent Silica-1> Silica fine powder synthesized by a dry method (BET specific surface area 200 m ²
/ G) 20 parts of a silicone oil having a side chain amino group (viscosity at 25 ° C .: 96 mPa · s, amine equivalent: 2,160) while maintaining 100 parts with stirring at about 60 ° C.
A mixed solution consisting of 20 parts of petroleum ether (main distillate: around 60 ° C.) was sprayed, and the solvent was dried while stirring / treating. Then, the mixture was heated with stirring, the temperature was raised to 250 ° C., and the solvent was completely removed. The obtained silica fine powder is referred to as silica 1.

<Production Example 2 of Fluidizing Agent Silica-2> A silica fine powder (BET
Silicone oil having an amino group in a side chain in 100 parts of a specific surface area of 130 m ² / g (viscosity of 54 mP at 25 ° C.)
a.s, amine equivalent weight 1,500) 15 parts. The obtained silica fine powder is referred to as silica 2.

<Production Example of Composite Metal Oxide M-1> 600 g of strontium carbonate and 320 g of titanium oxide were wet-mixed in a ball mill for 8 hours, dried by filtration, and molded at a pressure of 5 kg / cm ^2. It was calcined at 1,100 ° C. for 8 hours. This was mechanically pulverized to a weight average particle size of 1.9.
Thus, strontium titanate: SrTiO ₃ (composite metal oxide M-1) having a number average particle size of 1.1 μm was obtained.

<Production Example of Composite Metal Oxide M-2> 1,500 g of strontium carbonate, 180 g of silicon oxide, and 560 g of titanium oxide were wet-mixed in a ball mill for 8 hours, filtered and dried, and the mixture was dried at 5 kg / cm. ^It was molded at a pressure of ² and calcined at 1300 ° C. for 8 hours. This was mechanically pulverized to a weight average particle size of 2.2 μm and a number average particle size of 1.1 μm.
pulverized product (M) containing strontium silicate (SrSiO ₃ ) and strontium titanate (SrTiO ₃ )
-2) was obtained. That is, the resulting (M-2) was carried out X-ray diffraction analysis, from the peak pattern, a composite oxide was produced, and _{[Sr] a [Si] b} O c, [Sr] b [Ti] e O _f
A = 1, b = 1, c =
3, d = 1, e = 1 and f = 3 were confirmed.

The measuring conditions of X-ray diffraction are as follows. X-ray diffractometer used: X-ray diffractometer CN2013
(Rigaku Denki Co., Ltd.) Apparatus for preparing a measurement sample: powder sample molding machine PX-700 Using the above molding apparatus, a measurement sample is compression-pressed.
The molded sample is set on an X-ray diffractometer and measured under the following conditions. The peak intensity of the obtained X-ray diffraction pattern and 2
The structure is determined from the θ angle.・ Target, Filter Cu, Ni ・ Voltage, Current 32.5kV, 15mA ・ Counter Sc ・ Time Constant 1sec ・ Diversence Slit 1 ° ・ Receiving Slit 0.15mm ・ Scatter Slit 1 ° eng６０60 ° Ang

<Production Example of Developing Sleeve 2A> 1 part of conductive carbon (average particle diameter 30 nm) 9 parts of graphite (average particle diameter 10 μm) 9 parts of phenolic resin 65 parts of isopropyl alcohol The above-mentioned coating material mixture was sand-milled. 5 at room temperature using
Dispersed for minutes. The obtained dispersion is diluted with isopropyl alcohol to a solid content of 20% by mass to form a coating liquid, and then a surface having an outer diameter of 20 mmφ is blasted with abrasive grains of FGB # 300 to form irregularities, thereby forming aluminum. A 10 μm-thick coating was applied to the base of a magnet sleeve (a magnet roll used for NP9330), and then heated at 150 ° C. for 30 minutes in a hot-air drying oven to cure and form a coating. Further, after the surface of this sleeve is polished with # 3000 sandpaper, it is washed with ethanol to form a developing sleeve 2A.
I got The JIS center line average roughness (Ra) of the developing sleeve 2A was 0.5 μm.

<Production Example of Developing Sleeve 2B> 1 part of conductive carbon (average particle diameter 25 nm) 9 parts of graphite (average particle diameter 7 μm) 9 parts of polycarbonate resin 20 parts of isopropyl alcohol Developing sleeve using the above materials A developing sleeve 2B was manufactured by performing the same processing as in the manufacturing example of 2A. The JIS center line average roughness (Ra) of the developing sleeve 2B is 0.65 μm
Met.

<Production Example of Developing Sleeve 2C> ・ 100 parts of polyamide resin ・ 40 parts of potassium titanate (average particle size: 0.8 μm) ・ 20 parts of carbon black (average particle size: 30 nm) After forming into a pellet, the mixture was extruded into a sleeve using a single screw extruder and air-cooled to form a resin developing sleeve having a thickness of 1.1 mm and an outer diameter of 20 mmφ. The outer surface of this sleeve is subjected to sand blasting (using FGB # 300), a conductive paint is applied to the inner surface, and the sleeve is attached to a magnet roll used in a developing sleeve of a Canon NP9330 copier to produce a developing sleeve 2C. did. After the developing sleeve 2C was polished with wrapping paper, it was washed with ethanol. The JIS center line average roughness (Ra) of the developing sleeve 2C was 0.7 μm.

<Comparative Manufacturing Example of Developing Sleeve 2D> A developing sleeve 2D was obtained in the same manner as in the manufacturing example of the developing sleeve 2A, except that the resin layer was not provided on the surface in the manufacturing example of the developing sleeve 2A. The JIS center line average roughness (Ra) of the developing sleeve 2D was 0.6 μm.

<Comparative Manufacturing Example of Developing Sleeve 2E> In the manufacturing example of the developing sleeve 2A, the development was performed in the same manner as in the manufacturing example 4 of the developing sleeve, except that the polishing process was not performed after the resin layer was provided on the sleeve surface. A sleeve 2E was obtained. The JIS center line average roughness (Ra) of the developing sleeve 2E is
It was 1.8 μm.

<Comparative Manufacturing Example of Developing Sleeve 2F> In the manufacturing process of the developing sleeve 2B, the polishing conditions were strengthened to reduce the JIS center line average roughness (Ra) to 0.1.
A μm developing sleeve 2F was obtained.

Example 8 Magnetic Toner 2 Obtained Above
A (100 parts), 0.6 part of silica 1 and 2.0 parts of composite metal oxide M-1 were added and mixed with a Henschel mixer to obtain a positively chargeable magnetic toner (developer) 2A. When this positively chargeable magnetic toner 2A was measured using a Coulter Multisizer II having an aperture of 100 μm, the weight average particle diameter (D ₄ ) was 7.50 μm, and the coefficient of variation A of the number distribution was 23.1. there were. The measurement was 1.82.
The calculation was performed within the range of 6 to 63.490 μm, and the statistical calculation was performed using 50,000 toner particles by dividing this range into 256 sections.

The positively-chargeable magnetic toner 2A was charged into a machine made by modifying a Canon digital copying machine NP9330 equipped with an amorphous silicon drum at a process speed of 230 mm / s. The developing sleeve 2A was used as a developing sleeve. Under normal temperature / humidity environment (23 ℃ / 60%
RH; N / N) under normal temperature / low humidity environment (23 ° C / 5% R
H; N / L) and high temperature / high humidity environment (30 ° C./80%)
(RH; H / H), a 100,000-sheet continuous image output test was performed. The gap between the latent image carrier and the developing sleeve is 26
It was set to 0 μm. As for the developing bias, a rectangular wave bias shown in FIG. 8 was used as the AC voltage component. At this time, the frequency was 1,800 Hz, the absolute value of the bias voltage (Peak to Peak) was 1,300 V, and the DC voltage was 350 V. The dark portion potential was 430 V and the bright portion was 40 V, and development was performed by reversal development. Further, the peripheral speed of the developing sleeve (with respect to the latent image carrier) is 1
It was set to 50%. As the image forming apparatus, an apparatus having a configuration shown in FIG. 10 was used. The results of the image evaluation are shown in Table 4, and a good image could be obtained all the time under any environment.

(Example 9) Magnetic toner 2B (100 parts)
0.8 parts of silica 2 and 2. parts of composite metal oxide M-2.
Five parts were added and mixed with a Henschel mixer to obtain a positively-chargeable magnetic toner (developer) 2B. The weight average particle diameter of the positively chargeable magnetic toner 2B was 6.53 μm, and the coefficient of variation A was 28.9% (using Coulter Multisizer II). This positively chargeable magnetic toner 2B was continuously used under the same conditions as in Example 1 except that the developing sleeve was changed to 2B.
An image output test for 10,000 sheets was performed. The results of the image evaluation are shown in Table 4, and good results were obtained in any environment. Furthermore, the density gradation property in the photographic image was excellent, and generation of sleeve ghost was not observed throughout.

Example 10 An image was evaluated under the same conditions as in Example 8, except that the process speed was changed to 290 mm / s. As shown in Table 4, the results were good.

(Embodiment 11) Image evaluation was performed in the same manner as in Embodiment 8, except that the developing bias was changed to the asymmetric rectangular wave bias (duty ratio 35%) shown in FIG. did. As shown in Table 4, the result was good without any difference from the case of Example 8.

Example 12 The same image evaluation as in Example 8 was performed, except that the process speed was changed to 175 mm / s. The result was no problem as shown in Table 4.

(Embodiment 13) In Embodiment 8, except that a developing sleeve 2C is used instead of the developing sleeve 2A,
The same image evaluation as in Example 8 was performed. As shown in Table 4, good results were obtained.

(Example 14) In Example 8, the developing device and the magnet roll were changed to a non-magnetic two-component type. For the developing device, non-magnetic toner 2C (100 parts)
Silica 2 (0.8 parts) and composite metal oxide M-1 (2
3) (Coulter Multisizer II)
According to the measurement according to the above, D ₄ was 9.4 μm, and variation coefficient A was 2
1.9) and 97 parts of a ferrite carrier coated with a silicone resin and 97 parts of a positively-chargeable non-magnetic toner (developer) 2C. This positively chargeable non-magnetic toner 2
C was put in a modified machine of NP9330 in the same manner as in Example 8 and evaluated. Regarding the development conditions, the absolute value of the bias voltage (Peak to Peak) was set to 1,400 V
Then, the same setting as in Example 8 was performed except that the peripheral speed of the developing sleeve (with respect to the latent image carrier) was changed to 110%. The results of the image evaluation are shown in Table 4, and a good image could be obtained all the time under any environment.

(Comparative Example 7) Evaluation was performed under the same conditions as in Example 8 except that the magnetic toner 2D was used. D ₄ of the toner after external addition is 3.66 μm, and variation coefficient A is 3
5.9. As a result of the image evaluation, as shown in Table 4, adverse effects such as uneven toner coating on the sleeve and deterioration of fog due to charge-up in a low humidity environment occurred.

[0208] (Comparative Example 8) D ₄ produced by further changing the pulverization / classification condition in the magnetic toner 2D is 12.8μm
Then, an image evaluation was performed under exactly the same conditions as in Example 8 except that a magnetic toner 2D ′ having a variation coefficient of 27.1 was obtained and used. The results are as shown in Table 4. In particular, the developability (density reduction, deterioration of image quality, etc.) in a high humidity environment was not excellent.

(Comparative Example 9) An image was evaluated in the same manner as in Example 8 except that silica 1 was not added to the positively chargeable magnetic toner 2A. As shown in Table 4, the image density was lower than that at the start in any environment, and the image quality (density gradation) was very rough and the level was extremely poor. The evaluation was suspended at 50,000 sheets.

Comparative Example 10 An image was evaluated in the same manner as in Example 8, except that the composite metal oxide M-1 was not added to the positively chargeable magnetic toner 2A. Table 4 shows the results. In particular, problems such as low image density at the start under high humidity and poor density gradation during durability were observed.

(Comparative Example 11) An image was evaluated under the same conditions as in Example 8 except that the magnetic toner 2D was used. The results are as shown in Table 4, and a decrease in developability due to durability was observed under any environment. Also, the level of the sleeve ghost was bad both at the start and during the endurance.

Comparative Example 12 Image evaluation was performed in the same manner as in Example 8, except that the developing sleeve 2E was used.
Table 4 shows the evaluation results. In particular, adverse effects such as a low initial image density in a high humidity environment and deterioration of fog due to durability occurred.

Comparative Example 13 Image evaluation was performed in the same manner as in Example 9 except that the developing sleeve 2F was used.
Table 4 shows the evaluation results. There were problems such as a decrease in density under low humidity and uneven toner coating on the sleeve. Also, the density gradation in the photograph mode was remarkably inferior to Example 9.

Table 3: Toner and developer carrier used in Examples and Comparative Examples

Table 4: Image evaluation results

[0216]

According to the first aspect of the present invention, as described above, the developing sleeve having a specific structure and a binder resin having a specific amount of an acid value are contained. In a method of forming a digital latent image by reversal development using a developer having a negatively chargeable toner having a specific particle size distribution, the following excellent effects are exhibited. (1) Even when copying many sheets over a long period of time, a high reflection image density is maintained throughout, and a copied image having excellent image quality and no fogging can be obtained. (2) A high-density and high-quality image can be obtained in any environment from low humidity to high humidity. (3) Even in a digital latent image system in a case where the process speed is high, a high-quality copy image can be obtained without any change at the start and after the endurance.

[Second Invention] As described above, according to the second invention of the present invention, a developing sleeve having a specific structure, a fluidizing agent and a metal oxide powder having a specific particle size are used. In a method of forming an image of a digital latent image by reversal development using a developer having a positively chargeable toner externally mixed, the following excellent effects are exhibited. (1) Even when copying many sheets over a long period of time, a high reflection image density is maintained throughout, and a copied image having excellent image quality and no fogging can be obtained. (2) High density and high quality images can be obtained in any environment from low humidity to high humidity. (3) Even in a digital latent image system in which the process speed is high, a high-quality copy image can be obtained at the start and after the endurance.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an asymmetric bias and a duty ratio of an alternating electric field used in the first invention.

FIG. 2 is a schematic diagram of a bias waveform of an alternating electric field used in Examples 1, 3, 4, and 6 and Comparative Examples 1 to 7.

FIG. 3 is a schematic diagram of a bias waveform of an alternating electric field used in Example 2.

FIG. 4 is a schematic diagram of a bias waveform of an alternating electric field used in Example 5.

FIG. 5 is a schematic diagram of a bias waveform of an alternating electric field used in Example 7.

FIG. 6 is an explanatory diagram of an example of an image forming apparatus used in the first invention.

FIG. 7 is a diagram for explaining an asymmetric bias and a duty ratio of an alternating electric field used in the second invention.

FIG. 8 is a schematic diagram of a bias waveform of an alternating electric field used in Examples 8, 9, 10, 12, 13, 14 and Comparative Examples 7 to 13.

FIG. 9 is a schematic diagram of a bias waveform of an alternating electric field used in Example 11.

FIG. 10 is an explanatory diagram of an example of an image forming apparatus used in the second invention.

[Explanation of symbols]

 100: latent image carrier 102: developing sleeve 103: magnetic blade 104: magnet roller 114: transfer charger or transfer roller 116: cleaner 117: primary charging roller or primary corona charger 121: laser generator 123: laser beam 124: Paper feed roller 125: conveyor belt 126: fixing device 140: developing device

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G03G 9/08 374

Claims (13)

[Claims] A digital latent image on a latent image carrier is reversely developed by transferring a negatively chargeable toner onto a latent image carrier for negative charging by a bias voltage applied to a developer carrier. In an image forming method for forming a toner image,
A process speed of 160 to 300 mm / s,
At least the surface of the developer carrying member is formed of a resin containing a conductive or semiconductive fine powder, and the surface has a JIS center line average roughness (Ra).
Is 0.2 to 1.0 μm, and contains at least a binder resin and a colorant as the negatively chargeable toner, and the binder resin has an acid value of 2 to 70 mgKOH / g.
And an image forming method using a negatively chargeable toner having a weight average particle diameter of 4 to 11 μm. 2. The image forming method according to claim 1, wherein the negatively chargeable toner is a negatively chargeable magnetic toner containing a magnetic material as a colorant. 3. The image forming method according to claim 1, wherein the negatively chargeable toner is a negatively chargeable nonmagnetic toner containing no magnetic material. 4. The toner according to claim 1, wherein the variation coefficient A of the number distribution represented by the following equation is 40% or less.
4. The image forming method according to any one of claims 1 to 3. A = S _n / D ₁ × 100 [ _where Sn is the standard deviation of the number distribution, D ₁ is the number-based length average particle diameter (μm)] 5. The developer carrier according to claim 1, wherein the developer carrier has a substrate and a resin layer provided on the surface thereof, and the surface of the resin layer is polished. Image forming method. 6. A digital latent image on a latent image carrier is reversely developed by transferring a positively chargeable toner onto a positively charged latent image carrier by a bias voltage applied to a developer carrier. An image forming method for forming a toner image, comprising:
A process speed of 160 to 300 mm / s,
At least the surface of the developer carrying member is formed of a resin containing a conductive or semiconductive fine powder, and the surface has a JIS center line average roughness (Ra).
Is 0.2 to 1.0 μm, and as the positively chargeable toner, a toner particle containing at least a binder resin and a colorant has a BET specific surface area of 30 to 50.
a glidant m ² / g, weight average particle diameter of 0.4 to 5.5
An image forming method, comprising using a positively chargeable toner having a weight average particle size of 4 to 11 μm containing a powdered metal oxide of μm. 7. The image forming method according to claim 6, wherein the positively chargeable toner is a positively chargeable magnetic toner containing a magnetic material as a colorant. 8. The image forming method according to claim 6, wherein the positively chargeable toner is a positively chargeable nonmagnetic toner containing no magnetic material. 9. The toner according to claim 6, wherein the variation coefficient A of the number distribution represented by the following equation is 40% or less.
9. The image forming method according to any one of claims 1 to 8. A = S _n / D ₁ × 100 [ _where Sn is the standard deviation of the number distribution, D ₁ is the number-based length average particle diameter (μm)] 10. The image forming method according to claim 6, wherein the fluidizing agent is a hydrophobic silica fine powder. 11. The image forming method according to claim 6, wherein the metal oxide is a composite metal oxide represented by the following formula. [M] _a [Ti] _b O _c (where M is Sr, Mg, Zn, Co, Mn and C
e represents a metal element selected from the group consisting of
Represents an integer up to 9, and c represents an integer from 3 to 9) 12. The image forming method according to claim 6, wherein the metal oxide is a composite metal oxide represented by the following formula. [M1] _a [Si] _b O _c, [M2] _d [Ti] _e O _f (in the above formula, respectively are M1 and M2, Sr, Mg, Zn,
Represents a metal element selected from Co, Mn and Ce,
a, b, d and e each represent an integer from 1 to 9;
And f each represent an integer from 3 to 9) 13. The developer carrier according to claim 6, wherein the developer carrier has a substrate and a resin layer provided on the surface thereof, and the surface of the resin layer is polished. Image forming method.