JPH11133670A - Image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-quality image which is excellent in fine line reproducibility and gradation property, does not damage a member such as a developer carrier by toner, does not contaminate it, and has fixability and anti-offset property. It is another object of the present invention to provide an image forming method which satisfies the requirements to a high degree. SOLUTION: A developer layer is formed on a developer carrier facing the electrostatic latent image carrier, and an electrostatic latent image carried on the electrostatic latent image carrier is transferred onto the developer carrier. In the image forming method including the step of developing with a developer, the developer carrier has at least a substrate and a coating layer covering the substrate, and the coating layer includes a binder resin, The developer contains at least conductive spherical particles and a nitrogen-containing heterocyclic compound dispersed in a resin, and the developer has a melt index MI ₁₂₅ (125 ° C., 5 kg load) of 0.5 g / 10 m.
The present invention relates to an image forming method comprising a toner having a toner density of 35 g / 10 min.

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 image formed by an electrophotographic method, an electrostatic printing method, or the like.

[0002]

2. Description of the Related Art In recent years, devices using electrophotography have begun to be used not only for copying original documents but also for copying high-resolution images such as digital printers or graphic designs as computer outputs.
As a result, the resolution of the printer device is 240, 3
400 dpi, 600 dpi, 1200d
pi, and the development of devices with higher image quality and higher definition is desired.

[0003] Therefore, higher reliability has been strictly pursued, and the required performance has become higher, and if the performance improvement of the image forming method including the toner cannot be achieved, a better machine is required. It is no longer feasible.

Conventionally, as an electrophotographic method, US Pat.
A number of methods are known as described in Japanese Patent Publication No. 297,681, Japanese Patent Publication No. 42-23910, and Japanese Patent Publication No. 42-4748. Forming an electric latent image on the photoreceptor by means of (1), (2) developing the latent image with toner to form a visible image, and, if necessary, transferring the toner image to a transfer material such as paper. The toner image is fixed on the transfer material by pressure or the like to obtain a copy, and the remaining toner which has not been transferred onto the photoreceptor is cleaned by various methods, and the above steps are repeated.

As a method of developing an electric latent image on a photoreceptor, toner particles are formed on a photosensitive drum by friction between particles of magnetic toner and friction between a sleeve as a toner carrier and magnetic toner particles. A charge having a polarity opposite to that of the electrostatic image charge and the development reference potential is applied to the magnetic toner particles, the magnetic toner is applied very thinly on the sleeve, and is conveyed to a development area formed by the photosensitive drum and the sleeve. In a developing area fixed in a sleeve in a region, a magnetic toner is caused to fly by the action of a magnetic field by a magnet fixed in the sleeve, and an electrostatic latent image on a photosensitive drum is made visible.

However, when such a one-component developer is used, it is difficult to adjust the charge of the toner, and although various measures have been taken with the developer, problems relating to non-uniform charging and durability stability of the charge have been made. Is not completely resolved.

In particular, as the sleeve rotates repeatedly, the amount of charge of the toner coated on the sleeve becomes too high due to the contact with the sleeve, and the toner is attracted by the reflection force on the sleeve surface, and the surface of the sleeve is attracted. A so-called charge-up phenomenon, in which the above-mentioned state becomes immobile and does not move from the sleeve to the latent image on the latent image holding member (drum), tends to occur particularly under low humidity. When such a charge-up occurs, the toner in the upper layer becomes difficult to be charged, and the development amount of the toner is reduced, so that a thin line image or a low image density of a solid image occurs.

Further, in order to realize high image quality and high definition, a toner excellent in fine line reproducibility and gradation is desired, and accordingly finer toner is required. However, as the toner becomes finer, the toner is more likely to adhere electrostatically on the sleeve, and the toner is subjected to physical force by a regulating blade or the like, so that toner contamination or fusion to the sleeve surface is likely to occur. Become.

As a method of solving such a phenomenon, a method in which a sleeve in which a coating layer in which a solid lubricant and a conductive powder such as carbon black are dispersed in a resin is provided on a metal substrate is used in a developing device. Has been proposed. It is recognized that the use of this method greatly reduces the above-mentioned phenomenon. However, in this method, since the shape of the sleeve surface becomes uneven, uniform charging and charging ability given to the developer are still insufficient, and further, there is a problem in terms of durability such as embrittlement of the coating layer. is there.

Further, as disclosed in JP-A-3-200986, a conductive coating layer in which a conductive fine powder such as a solid lubricant and carbon black and further spherical particles are dispersed in a resin is coated on a metal substrate. A method of using the provided sleeve for a developing device has been proposed. By using this method, the shape of the sleeve surface is made uniform, and the uniformity of charging and the abrasion resistance are improved. However, even in this method, when the developing sleeve is used under severe durability conditions, etc., the dispersibility of the spherical particles is still insufficient, so that the abrasion of the conductive coating layer is liable to occur. If the spherical particles inside are exposed on the surface of the sleeve, toner contamination or fusion is likely to occur with the spherical particles as nuclei, so that further improvement in durability is desired.

[0011] Further, as disclosed in Japanese Patent Application Laid-Open No. 2-176762, the rising of the charge of the toner is improved,
Further, there has been proposed a method of using a sleeve in which a charge control agent is contained in a coating layer on a sleeve surface in a developing device in order to uniformly charge the toner. By using this method, the rise of toner charge and the uniform charging of the toner are improved to some extent, but they still exert sufficient effects on high image quality with excellent character sharpness and image density stability under high temperature and high humidity. To this extent, the charging of the surface of the developing sleeve is not sufficiently imparted, and the durability is still unsatisfactory, and further improvement is desired.

On the other hand, many studies have been made to improve the performance of the developer (toner).

For example, in order to reduce the power consumption of the electrophotographic apparatus itself, many toners have been studied to lower the fixing point (the temperature at which the toner softens when heated).

In designing such a toner, generally, the thermal characteristics of a binder, which is a toner constituent material, and the thermal characteristics of a wax are improved to control the thermal characteristics of the toner. However, when the thermal characteristics of the toner are shifted to a lower temperature side, the developing characteristics are deteriorated.In addition, when a large number of images are output under a high temperature and a high humidity, the toner contaminates a member such as a developer carrying member. This is not preferable because a problem occurs. Conversely, if the thermal characteristics of the toner are shifted to a higher temperature side, even if the developing characteristics are good, the fixing point becomes high, which is not preferable.

In order to solve these problems, it is necessary to control the sleeve structure, the thermal characteristics of the toner and the like to find an optimum image forming method. However, this method is still insufficient and has many points to be improved. ing.

[0016]

SUMMARY OF THE INVENTION It is an object of the present invention to greatly improve the problems of the prior art and to enable the output of a high-resolution and high-definition image with excellent fine line reproducibility and gradation. An object of the present invention is to provide an image forming method.

It is a further object of the present invention to provide an image forming method capable of outputting a high image density from the beginning even under different environments and exhibiting good image density stability.

It is a further object of the present invention to provide an image forming method which does not damage or contaminate a developer carrying member, a developer regulating member and the like with toner.

It is a further object of the present invention to provide an image forming method exhibiting high performance in fixing property and anti-offset property.

[0020]

Means for Solving the Problems The inventors of the present invention have solved the above-mentioned various problems, and have arrived at the following invention in the course of intensive studies for developing an image forming method which meets the above-mentioned object of the present invention. .

That is, according to the present invention, a developer layer is formed on a developer carrier facing an electrostatic latent image carrier, and an electrostatic latent image carried on the electrostatic latent image carrier is formed on the developer layer. In an image forming method including a step of developing with a developer on a developer carrier, the developer carrier has at least a substrate and a coating layer covering the substrate. The developer contains at least a conductive resin, conductive spherical particles dispersed in the binder resin, and a nitrogen-containing heterocyclic compound. The developer has a melt index MI ₁₂₅ (125 ° C., 5 kg load) of 0.5 g / The present invention relates to an image forming method having a toner of 10 min to 35 g / 10 min.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present inventors consider the reason why the image forming method according to the present invention exerts the effects of the present invention as follows.

By defining the structure of the coating layer of the developer carrier according to the present invention, rapid charging is performed at the interface between the developer carrier and the developer, while the developer carrier itself discharges smoothly. Therefore, high image density can be output from the beginning without charging up. Further, by dispersing the conductive spherical particles and the nitrogen-containing heterocyclic compound in the binder resin in the conductive coating layer, a stable chargeability of the developer can be obtained. And a stable charge application to the developer is obtained.

However, when a toner that is too hard or too soft is used for the developer, the effect of the developer carrier of the present invention cannot be sufficiently obtained. That is, since the dispersibility of the charge control agent contained in the toner is determined by the state of the matrix inside the toner, in the case of a toner that is too hard or too soft, the matrix inside the toner is dense or coarse, and the charge control is not necessarily performed. Agents are not evenly dispersed. Even when such a toner is combined with the developer carrying member of the present invention, the charge is not generated between the spherical carbon particles or the nitrogen-containing heterocyclic compound in the coating layer of the developer carrying member and the charge control agent in the toner. Since it is not performed efficiently, a high image density from the beginning cannot be obtained.

Further, when the toner which is too hard is pressed against the developer carrier by a developing blade or the like, the toner surface of the developer carrier is damaged, resulting in streak-like image defects. vice versa,
A toner that is too soft adheres to the developer carrying member during a print test of a large number of sheets under high temperature and high humidity, and causes problems such as toner contamination or fusing.

In order for the developer carrying member of the present invention to fully exhibit its effects without eliminating the above-mentioned disadvantages, it is necessary to regulate the hardness and softness (MI) of the toner.

On the other hand, defining the MI of the toner is important in controlling the fixing characteristics.

Therefore, it is considered that the above-described configuration enables image formation with a good balance between the developing characteristics and the fixing characteristics. That is, when a large number of images are output, toner contamination or fusing to the developer carrier does not occur, high image density is maintained from the beginning, high dot reproducibility, high image quality with little toner scattering In addition, good image quality and image density can be obtained even in an environment such as high temperature, high humidity, and low temperature and low humidity, and the effect of being excellent in fixability and offset resistance can be obtained.

Further, the present invention will be described in detail.

First, the conductive spherical particles used for the conductive coating layer coated on the surface of the substrate constituting the developer carrier of the present invention will be described.

The conductive spherical particles used in the present invention have a number average particle size of 0.3 to 30 μm, preferably 2 to 2 μm.
It is preferably 0 μm and the true density satisfies ³ g / cm ³ or less.

The conductive spherical particles maintain uniform surface roughness on the surface of the conductive coating layer of the developer carrying member,
Even if the surface of the coating layer is worn, the surface roughness of the coating layer is not changed much, and toner contamination and toner fusion are hardly generated.

The conductive spherical particles interact with the nitrogen-containing heterocyclic compound contained in the conductive coating layer to form
The effect of the nitrogen-containing heterocyclic compound is further enhanced, quick and uniform charging is further improved, and the charging performance is also stabilized.

The number average particle diameter of the conductive spherical particles is 0.3 μm.
If less than m, the effect of imparting a uniform roughness to the surface and the effect of improving the charging performance are small, and the rapid and uniform charging of the developer becomes insufficient, and the toner is charged up due to abrasion of the conductive coating layer. In addition, toner contamination and toner fusion occur, which tends to cause deterioration of sharpness and ghost of a character line of an obtained image and a decrease in image density. When the number average particle size exceeds 30 μm, the surface of the conductive coating layer has too large a roughness, which makes it difficult to sufficiently charge the toner and decreases the mechanical strength of the coating layer. Therefore, it is not preferable.

The true density of the conductive spherical particles used in the present invention is 3 g / cm ³ or less, preferably 2.7 g / cm ^3.
m ³ or less, more preferably 0.9 to 2.3 g / cm ³ . That is, the true density of the conductive spherical particles is 3 g /
When it exceeds cm ^3, because the dispersibility of the spherical particles in the conductive coating layer is insufficient, it becomes difficult to impart a uniform roughness to the surface of the coating layer, dispersibility of the nitrogen-containing heterocyclic compounds This is not preferable because it is not performed uniformly, and the toner is charged quickly and uniformly and the strength of the coating layer becomes insufficient.

In the present invention, as the conductivity of the conductive spherical particles, particles having a volume resistance of 10 ⁶ Ω · cm or less, preferably particles having a volume resistance of 10 ³ to 10 ^-6 Ω · cm are used. I do.

The volume resistivity of the conductive spherical particles is 10 ⁶ Ω · c.
If it exceeds m, the toner is likely to be contaminated or fused by spherical particles exposed on the surface of the conductive coating layer due to abrasion, and it is difficult to perform quick and uniform charging.

The term "spherical" in the conductive spherical particles means that the ratio of the major axis / minor axis is about 1.0 to 1.5, and in the present invention, the ratio of the major axis / minor axis is preferably It is preferred to use particles of 1.0 to 1.2.

The ratio of the major axis / minor axis of the conductive spherical particles is 1.5
When it exceeds, the dispersibility of the conductive spherical particles in the conductive coating layer is reduced, the dispersibility of the nitrogen-containing heterocyclic compound in the conductive coating layer is reduced, and the surface roughness of the coating layer is not uniform. This is undesirable in terms of quick and uniform charging of the toner and strength of the conductive coating layer.

As a method for obtaining the conductive spherical particles of the present invention, the following methods are preferred, but are not necessarily limited to these methods.

A particularly preferable method for obtaining conductive spherical particles used in the present invention is, for example, a method of firing resin-based spherical particles or mesocarbon microbeads to carbonize and / or graphitize to obtain a low-density and good graphite. A method of obtaining conductive spherical carbon particles may be used. Examples of the resin used for the resin-based spherical particles include phenol resin, naphthalene resin, furan resin, xylene resin, divinylbenzene polymer, styrene-divinylbenzene copolymer, and polyacrylonitrile.

The mesocarbon microbeads can be usually produced by washing spherical crystals generated in the process of heating and firing the medium pitch with a large amount of a solvent such as tar, medium oil and quinoline.

As a more preferable method for obtaining conductive spherical particles, a spherical resin particle surface such as a phenol resin, a naphthalene resin, a furan resin, a xylene resin, a divinylbenzene polymer, a styrene-divinylbenzene copolymer, and a polyacrylonitrile is used. The bulk mesophase pitch is coated by a mechanochemical method, and the coated particles are heat-treated in an oxidizing atmosphere, and then calcined in an inert atmosphere or vacuum to be carbonized and / or graphitized to obtain conductive spherical carbon particles. Method. Spherical carbon particles obtained by this method are more preferable because, when they are graphitized, the coating of the obtained spherical carbon particles has advanced crystallization, so that the conductivity is improved.

The conductive spherical carbon particles obtained by the above-mentioned method can be controlled to some extent by changing the firing conditions in any of the methods. Is preferably used. Further, the spherical carbon particles obtained by the above method,
In some cases, in order that the true density of the conductive spherical particles does not exceed ³ g / cm ³ to further increase the conductivity,
It may be plated with a conductive metal and / or metal oxide.

As another method for obtaining the conductive spherical particles used in the present invention, there is a method in which conductive fine particles smaller than the particle diameter of the core particles are mechanically mixed with the core particles composed of the spherical resin particles at an appropriate mixing ratio. After the conductive fine particles are uniformly attached around the core particles by the action of van der Waals force and electrostatic force by mixing, the core particles are caused by a local temperature rise caused by, for example, applying a mechanical impact force. The method includes softening the surface, forming conductive fine particles on the surface of the core particles, and obtaining conductive resin-treated spherical resin particles. For the core particles, it is preferable to use spherical resin particles having a small true density made of an organic compound.Examples of the resin include PMMA, acrylic resin, polybutadiene resin, polystyrene resin, polyethylene, polypropylene, polybutadiene, or These copolymers, benzoguanamine resin, phenol resin, polyamide resin, nylon, fluorine resin, silicone resin, epoxy resin, and polyester resin are exemplified. Core particles (base particles)
The conductive fine particles (small particles) used when forming a film on the surface of
It is preferable to use a small particle having a particle size of 1/8 or less of the particle size of the base particle.

Still another method for obtaining the conductive spherical particles used in the present invention is to uniformly disperse the conductive fine particles in the spherical resin particles, thereby obtaining the conductive spherical particles in which the conductive fine particles are dispersed. There is a method of obtaining. As a method of uniformly dispersing the conductive fine particles in the spherical resin particles, for example, after kneading the binder resin and the conductive fine particles to disperse the conductive fine particles, solidify by cooling, and pulverize to a predetermined particle size A method of obtaining conductive spherical particles by mechanical and thermal treatments to obtain conductive spherical particles; or adding a polymerization initiator, conductive fine particles and other additives to a polymerizable monomer, and uniformly dispersing with a dispersing machine. The dispersed monomer composition is suspended in an aqueous phase containing a dispersion stabilizer by a stirrer or the like so as to have a predetermined particle size, polymerization is performed, and spherical particles in which conductive fine particles are dispersed are obtained. There is a method of obtaining.

The conductive spherical particles in which the conductive fine particles obtained by these methods are dispersed are also mechanically mixed with the conductive fine particles having a particle diameter smaller than the above-mentioned core particles at an appropriate blending ratio, and the van der After the conductive fine particles are uniformly attached around the conductive spherical particles by the action of the Waals force and the electrostatic force, for example, the surface of the conductive spherical particles is caused by a local temperature rise caused by applying a mechanical impact force. May be softened, and conductive fine particles may be formed on the surface to further increase the conductivity.

The structure of the conductive coating layer of the developer carrier of the present invention is such that the binder resin of the conductive coating layer contains a nitrogen-containing heterocyclic compound in combination with the conductive spherical particles. The charging performance of the conductive coating layer is significantly improved, and the object of the present invention is achieved.

The reason is as follows. That is, when a charge control agent (mainly a compound such as an organometallic complex) is used to improve the charge-imparting ability of the developer carrier, ligands and metal salts are released from the charge control agent under high temperature and high humidity. However, not only can the sufficient charging performance not be exhibited, but also the image may be adversely affected. On the other hand, the nitrogen-containing heterocyclic compound does not have the above-mentioned problem and has a low molecular weight as compared with the organometallic complex compound. Therefore, the nitrogen-containing heterocyclic compound is well dispersed in the conductive coating layer with the developer carrier, and thus has a high charge-imparting ability. Therefore, when the toner is used in combination with a toner that can achieve low power consumption, the developing performance of the toner can be improved, and a desired developing performance can be obtained.

The above nitrogen-containing heterocyclic compound has a number average diameter of preferably 20 μm or less, more preferably 0.1 μm or less.
It is preferable to use one having a thickness of up to 15 μm. When the number average diameter of the nitrogen-containing heterocyclic compound exceeds 20 μm, poor dispersibility of the nitrogen-containing heterocyclic compound in the conductive coating layer occurs,
The effect of improving the charging performance becomes insufficient, which is not preferable.

Examples of the nitrogen-containing heterocyclic compound include aziridine compounds, pyrrole compounds, indole compounds, imidazole compounds, pyrazole compounds, pyridine compounds, quinoline compounds, isoquinoline compounds, acridine compounds,
Pyritazine compounds, pyrimidine compounds, pyrazine compounds and the like can be mentioned. These nitrogen-containing heterocyclic compounds can be used alone or in combination of two or more.

In particular, in order to promote the effects of the present invention, it is preferable to use an imidazole compound, and examples thereof include the following.

[0053]

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[0054]

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[0055]

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[0056]

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It is preferable that lubricating particles are further dispersed in the conductive coating layer constituting the developer-carrying member of the present invention in order to further promote the effects of the present invention. Examples of the lubricating particles include graphite, molybdenum disulfide, boron nitride, mica, graphite fluoride, silver-niobium selenide, calcium chloride-graphite, talc, fatty acid metal salts such as zinc stearate, and the like. Among them, graphite particles are particularly preferably used because the conductivity of the conductive coating layer is not impaired. These lubricating particles are
The number average particle diameter is preferably about 0.2 to 20 μm, and more preferably 1 to 15 μm. When the number average particle size of the lubricating particles is less than 0.2 μm,
When the number average particle size exceeds 20 μm, lubricity is not easily obtained, and when the number average particle size is more than 20 μm, the surface roughness of the conductive coating layer becomes uneven, so that the toner is uniformly charged, and the strength of the coating layer is low. Is not preferred.

As the binder resin material of the conductive coating layer constituting the developer carrier of the present invention, generally known resins can be used. For example, styrene resin, vinyl resin,
Thermoplastic resins such as polyether sulfone resin, polycarbonate resin, polyphenylene oxide resin, polyamide resin, fluororesin, cellulose resin, acrylic resin, epoxy resin, polyester resin, alkyd resin, phenol resin, melamine resin, polyurethane resin, A heat or light curable resin such as a urea resin, a silicone resin, and a polyimide resin can be used. Among them, those with release properties such as silicone resin and fluorine resin, or excellent in mechanical properties such as polyether sulfone, polycarbonate, polyphenylene oxide, polyamide, phenol, polyester, polyurethane, styrene resin and acrylic resin Are more preferred.

In the present invention, the volume resistivity of the conductive coating layer of the developer carrying member is preferably 10 ³ Ω · cm or less, more preferably 10 ³ -10 ⁻² Ω · cm. When the volume resistance of the coating layer exceeds 10 ³ Ω · cm, charge-up of the toner is apt to occur, and ghost deterioration and density reduction are liable to occur.

In the present invention, in order to adjust the volume resistance of the conductive coating layer, other conductive fine particles are dispersed in the conductive coating layer together with the conductive spherical particles and the nitrogen-containing heterocyclic compound. You may make it contain.

The conductive fine particles preferably have a number average particle size of 1 μm or less, more preferably 0.01 to 0.01 μm.
0.8 μm is preferred. When the number average particle diameter of the conductive fine particles dispersed and contained in combination with the conductive spherical particles and the nitrogen-containing heterocyclic compound in the conductive coating layer exceeds 1 μm, the volume resistance of the conductive coating layer is controlled to be low. And the toner charge-up phenomenon is likely to occur.

The conductive fine particles usable in the present invention include, for example, carbon black such as furnace black, lamp black, thermal black, acetylene black, and channel black; titanium oxide, tin oxide, zinc oxide, molybdenum oxide; Metal oxides such as potassium titanate, antimony oxide and indium oxide; metals such as aluminum, copper, silver, nickel, graphite,
Examples include inorganic fillers such as metal fibers and carbon fibers.

Next, the structure of the developer carrier of the present invention will be described.

The developer carrier of the present invention is mainly composed of a metal cylindrical tube as a base and a conductive resin layer surrounding and surrounding the metal cylindrical tube. As the metal cylindrical tube, mainly stainless steel and aluminum are preferably used.

The composition ratio of each component constituting the conductive coating layer will be described, which is a particularly preferable range in the present invention.

The content of the conductive spherical particles dispersed in the conductive coating layer is preferably from 2 to 120 parts by mass, more preferably from 2 to 8 parts by mass, per 100 parts by mass of the binder resin.
Particularly preferred results are obtained in the range of 0 parts by mass. When the content of the conductive spherical particles is less than 2 parts by mass, the effect of adding the conductive spherical particles is small, and when it exceeds 120 parts by mass, the chargeability of the toner may be too low.

The content of the nitrogen-containing heterocyclic compound contained in the conductive coating layer in combination with the conductive spherical particles is preferably from 0.5 to 60 parts by weight, based on 100 parts by weight of the binder resin. Particularly in the range of 1 to 50 parts by mass gives particularly preferable results. When the content of the nitrogen-containing heterocyclic compound is 0.
When the amount is less than 5 parts by mass, the effect of adding the nitrogen-containing heterocyclic compound is small, and when the amount exceeds 60 parts by mass, the volume resistance of the conductive coating layer becomes low and it is difficult to control the charge-up phenomenon. And it becomes difficult to obtain the effect of adding the conductive spherical particles.

When the conductive coating layer contains lubricating particles in combination, the content of the lubricating particles is determined by the amount of binder resin 1
Particularly preferred results are obtained in the range of preferably 5 to 120 parts by mass, more preferably 10 to 100 parts by mass with respect to 00 parts by mass. When the content of the lubricating particles exceeds 120 parts by mass, a decrease in the coating strength and a decrease in the charge amount of the toner are observed. In some cases, toner contamination tends to occur on the surface of the conductive coating layer.

When the conductive fine particles are dispersed and contained in the conductive coating layer, the content of the conductive fine particles of 1 μm or less is preferably 40 parts by mass with respect to 100 parts by mass of the binder resin. Parts or less, more preferably 2-3
Particularly preferred results are obtained when used in the range of 5 parts by mass.

That is, when the content of the conductive fine particles exceeds 40 parts by mass, a decrease in the film strength and a decrease in the charge amount of the toner are not preferred.

In the present invention, the roughness of the surface of the conductive coating layer is the center line average roughness (hereinafter, referred to as “Ra”).
Is preferably in the range of 0.2 to 4.5 μm, and more preferably in the range of 0.4 to 3.5 μm. If the Ra on the surface of the conductive coating layer is less than 0.2 μm, the toner transportability may be reduced and a sufficient image density may not be obtained, and the Ra on the surface of the conductive coating layer may exceed 4.5 μm. In this case, the toner transport amount becomes too large and the toner cannot be sufficiently charged.

The thickness of the conductive coating layer having the above structure is preferably 25 μm or less, more preferably 20 μm or less.
Hereinafter, the thickness is more preferably 4 to 20 μm to obtain a uniform film thickness, but is not particularly limited to this layer thickness. The thickness of these layers depends on the material used for the conductive coating layer.
It can be obtained if the amount is about 0 mg / m ² .

Hereinafter, a method for measuring physical properties relating to the developer carrying member will be described.

(1) Measurement of center line average roughness (Ra) Based on the surface roughness of JIS B0601, three points in the axial direction × 2 points in the circumferential direction = 6 points using a surf coder SE-3300 manufactured by Kosaka Laboratory. Each was measured and the average was taken.

(2) Measurement of Volume Resistance of Particles A granular sample was placed in an aluminum ring of 40φ, pressed under 2500 N, and subjected to a resistivity meter Loresta AP or Hiresta I.
The volume resistance is measured at P (both manufactured by Mitsubishi Yuka) using a four-terminal probe. The measurement environment was 20 to 25 ° C,
50 to 60% RH. (3) Measurement of Volume Resistance of Coating Layer A conductive coating layer having a thickness of 7 to 20 μm was formed on a PET sheet having a thickness of 100 μm, and was subjected to ASTM standard (D-991).
-82) and SRIS (230
1-1969), using a voltage drop type digital ohmmeter (manufactured by Kawaguchi Electric Works) provided with a four-terminal electrode for measuring the volume resistance of conductive rubber and plastic. The measurement environment is 20-25 ° C, 50-60R.
H%.

(4) Measurement of True Density of Spherical Particles The true density of the conductive spherical particles used in the present invention was measured using a dry type densitometer Acupic 1330 (manufactured by Shimadzu Corporation).

(5) Particle Size Measurement of Spherical Particles The particle number was measured using a Coulter LS-130 type particle size distribution meter (manufactured by Coulter, Inc.) of a laser diffraction type particle size distribution meter, and the number average particle size calculated from the number distribution was obtained. .

(6) Measurement of Particle Size of Conductive Fine Particle The particle size of the conductive fine particle is measured using an electron microscope.
The photographing magnification is set at 60,000 times. If it is difficult, the image is taken at a low magnification and then enlarged to 60,000 times. Measure the particle size of the primary particles on the photograph. At this time, the major axis and the minor axis are measured, and the average value is defined as the particle diameter.

Next, the developer constituting the present invention will be described in detail.

The developer of the present invention comprises at least a toner. The toner preferably contains a binder resin, a charge control agent, a plasticizer, etc., but is not particularly limited to these toner constituent materials. .

The MI ₁₂₅ (125 ° C., 5
kg load) 0.5g / 10min to 35g / 10m
in, preferably 1.5 g / 10 mi
n to 30 g / 10 min, more preferably 5.0 g
/ 10 min to 25 g / 10 min.

The reason why the MI value of the toner falls within this range is as follows. When the MI value is smaller than 0.5, the toner scrapes or damages the surface of the developer carrying member, thereby causing an image defect. In addition, the toner cannot be sufficiently fixed on the printing paper during heat fixing. On the other hand, when the MI value is larger than 35, when a large number of images are output, problems such as toner contamination or fusing to the developer carrying member, so-called offset at the time of heat fixing, and toner adhesion to the fixing roller are caused. Problems arise.

The measuring method of the MI value of the present invention is carried out according to the method A of JIS K7210. However, the measurement conditions were a temperature of 125 ° C. and a load of 5 kg, and the measured value was 10
Convert to minute value.

Examples of the kind of the binder resin used in the present invention include a homopolymer of styrene such as polystyrene and polyvinyltoluene and a substituted product thereof; a styrene-propylene copolymer, a styrene-vinyltoluene copolymer, Styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-
Octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-octyl methacrylate Copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene Styrene copolymers such as isoprene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polybutyral Silicone resins, polyester resins, polyamide resins, epoxy resins, polyacrylic acid resins, acrylonitrile copolymers, rosin, modified rosin,
Tempel resin, phenolic resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, paraffin wax,
Carnauba wax or the like can be used alone or in combination.

The polymerization method of the resin according to the present invention includes an emulsion polymerization method, a suspension polymerization method, and a solution polymerization method, and is appropriately selected depending on a polymer to be polymerized.

As the solvent used in the polymerization, xylene, toluene, cumene, cellosolve acetate, isopropyl alcohol, benzene and the like are used. In the case of a styrene monomer mixture, xylene, toluene or cumene is preferred. These solvents are appropriately selected depending on the polymer to be polymerized.

If necessary at the time of polymerization, a polyfunctional initiator, a crosslinking agent, a polymerization accelerator and the like may be used.

The toner of the present invention may be used as a charge control agent, such as an organic metal complex such as a metal salt of salicylic acid, a metal salt of an alkyl salicylic acid, a metal salt of a dialkylsalicylic acid, or a metal salt of naphthoic acid; a dye such as a monoazo dye; It preferably contains a monoazo dye derivative.

These charge control agents can be used alone or in combination of two or more.

When the above charge control agent is used in the toner,
The developer carrier of the present invention has good matching with the nitrogen-containing heterocyclic compound dispersed in the conductive coating layer, and is suitable for obtaining a high-definition image.

The charge control agent used in the present invention is represented by, for example, the following general formula (1).

[0092]

Embedded image

In particular, as a more effective charge control agent usable in the present invention,

[0094]

Embedded image

[0095]

Embedded image And a monoazo type titanium complex salt (2-2) represented by the following formula (1).

As the charge control agent, for example, a basic organometallic complex represented by the following general formula (3) can also be used.

[0097]

Embedded image

In particular, the charge control agents that can be used in the present invention are more effective.

[0099]

Embedded image And a naphthoic acid iron complex represented by

The content of the charge control agent is preferably from 0.1 to 5 parts by mass, more preferably from 0.2 to 3 parts by mass, per 100 parts by mass of the binder resin of the toner. When the ratio of the charge control agent is excessive, the frictional charging between the surface of the developer carrier and the toner surface is excessively performed, so that not only the toner is charged up, but also the fluidity of the toner is deteriorated, and the developer carrier is deteriorated. This is not preferable because toner circulation in the vicinity is hindered. On the other hand, if it is too small, a sufficient charge amount cannot be obtained, and high image quality cannot be obtained even when combined with the developer carrier of the present invention.

The toner of the present invention preferably contains a magnetic material. Examples of magnetic materials that can be used include magnetite, γ-iron oxide, ferrite, iron oxides such as iron-rich ferrite; metals such as iron, cobalt, and nickel, or aluminum and cobalt, copper, lead,
Magnesium, tin, zinc, antimony, beryllium,
Examples include alloys with metals such as bismuth, cadmium, manganese, selenium, titanium, tungsten, and vanadium, and mixtures thereof.

The content of the magnetic material is preferably about 20 to 200 parts by weight, particularly preferably 30 to 150 parts by weight, based on 100 parts by weight of the binder resin of the toner. If the magnetic material is too large, the image density decreases, which is not preferable. On the other hand, if the amount is too small, fog suppression is undesirably deteriorated.

As the coloring agent used in the present invention, conventionally known pigments or dyes such as carbon black and copper phthalocyanine are used. Further, even if the magnetic material is a colorant, it does not indicate anything.

In the present invention, it is preferable that the developer contains a wax as necessary. Examples of the wax used include paraffin wax and its derivatives, microcrystalline wax and its derivatives, Fischer-Tropsch wax and its derivatives, carnauba wax and its derivatives, and polyolefin wax and its derivatives. Includes block copolymers with monomers and graft-modified products. Among these waxes, higher aliphatic alcohol waxes are particularly preferably used.

These waxes are preferably used in an amount of 0.5 to 20 parts by mass based on 100 parts by mass of the binder resin. If the amount of the wax is too large, not only is the developing property lowered, but also the force for plasticizing the toner becomes too large, and the offset resistance is deteriorated.
On the other hand, when the amount is too small, the effect of the wax cannot be sufficiently obtained, which is not preferable.

The developer for developing an electrostatic charge image of the present invention is prepared by sufficiently mixing the toner constituting materials with a mixer such as a ball mill, and then melting, kneading, and kneading using a hot kneader such as a heating roll, a kneader or an extruder. It can be produced by kneading, cooling, solidifying, pulverizing, and strict classification.

The developer for developing an electrostatic image of the present invention is mixed with an inorganic fine powder or a hydrophobic inorganic fine powder in order to improve environmental stability, charge stability, developability, fluidity and storage stability. Preferably. For example, fine silica powder, fine titanium oxide powder, or a hydrophobized product thereof may be used. They are preferably used alone or in combination.

[0108] Silica fine powder is used for vaporizing silicon halide compounds.
The so-called dry process or fu
From dry silica called mud silica, water glass, etc.
Both so-called wet silicas produced can be used
Has few silanol groups on the surface and inside,
a_TwoO, SO _Three ^2-Fumed silica without production residues such as
preferable. In the case of fumed silica, for example,
For example, other metal halo such as aluminum chloride, titanium chloride, etc.
By using a halogenated compound together with a silicon halide.
To obtain composite fine powder of silica and other metal oxides
Is also possible and encompasses them.

Further, the silica fine powder is preferably subjected to a hydrophobic treatment. The hydrophobizing treatment is applied by chemically treating with an organic silicon compound or the like which reacts or physically adsorbs with the silica fine powder. A preferred method is to treat the dry silica fine powder produced by the vapor phase oxidation of the silicon halide compound with a silane coupling agent or simultaneously with the silane coupling agent and an organic silicon compound such as silicone oil. Is mentioned.

Examples of the silane coupling agent used in the hydrophobic treatment include dimethyldichlorosilane, trimethylchlorosilane, allyldimethylchlorosilane, hexamethyldisilazane, allylphenyldichlorosilane,
Examples thereof include benzyldimethylchlorosilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, divinylchlorosilane, and dimethylvinylchlorosilane.

The above-mentioned silica fine powder is treated with a silane coupling agent by drying the silica fine powder into a ground state by stirring or the like and reacting the vaporized silane coupling agent, or by dispersing silica in a solvent. The treatment can be performed by a generally known method such as a wet method in which a silane coupling agent is dropped and reacted.

Examples of the organosilicon compound include silicone oil. Preferred silicone oils are those having a viscosity of about 30 to 1,000 centistokes at 25 ° C., such as dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl silicone oil, and fluorine-modified silicone oil. Silicone oil and the like are preferred.

The silicone oil treatment may be carried out, for example, by directly mixing the silica fine powder treated with the silane coupling agent with the silicone oil using a mixer such as a Henschel mixer, or adding the silicone oil to the base silica. A method of injecting oil may be used. Alternatively, it may be prepared by dissolving or dispersing a silicone oil in an appropriate solvent, mixing with a base silica fine powder, and removing the solvent.

If necessary, an external additive other than silica fine powder or titanium oxide fine powder may be added to the developer for developing an electrostatic image of the present invention.

For example, lubricants such as Teflon, zinc stearate and polyvinylidene fluoride, among which polyvinylidene fluoride are preferred. Alternatively, abrasives such as cerium oxide, silicon carbide, and strontium titanate, among which strontium titanate is preferable. Alternatively, for example, a fluidity imparting agent such as titanium oxide and aluminum oxide, particularly a hydrophobic agent is preferable. A small amount of a caking preventing agent or a conductivity-imparting agent such as carbon black, zinc oxide, antimony oxide, and tin oxide, or white and black fine particles of opposite polarity can also be used as a developability improver.

The amount of the resin fine particles, inorganic fine powder or hydrophobic inorganic fine powder mixed with the toner is 0.1 to 5 parts by mass (preferably 0.1 to 3 parts by mass) per 100 parts by mass of the toner.
Parts by mass)

When the toner of the present invention is used as a two-component developer, non-coated carriers such as iron powder, ferrite powder, magnetite powder, glass beads, styrene-acrylic resin, silicone resin, fluorine-modified A carrier coated with an acrylic resin or the like, a granulated carrier, or the like can be used.

[0118]

Although the basic configuration and features of the present invention have been described above, the present invention will be specifically described based on the following embodiments. However, this does not limit the embodiment of the present invention at all. Parts in the examples are parts by mass.

Example 1 (Production Example 1 of Developer Carrier) Using a hybridizer (manufactured by Nara Instruments), spherical PMMA particles (11.1 μm,
1.28 g / cm ³ ) 100 parts of conductive carbon black was coated on 5 parts to obtain spherical conductive-treated resin particles J-1.

200 parts of resole type phenol resin solution (containing 50% methanol) 45 parts of graphite having a number average diameter of 6.0 μm 45 parts of conductive carbon black 8 parts of nitrogen-containing heterocyclic compound (formula 1) 3 parts isopropyl 130 parts of alcohol Zirconia beads having a diameter of 1 mm were added as media particles to the above-mentioned materials, dispersed for 2 hours by a sand mill, and the beads were separated using a sieve to obtain a stock solution.

Next, 10 parts of the conductive resin particles J-1 were added to 380 parts of the stock solution obtained above, and the solid content was adjusted to 3 parts.
After adding isopropyl alcohol to 2%,
The mixture was dispersed for 1 hour using glass beads having a diameter of 3 mm, and the beads were separated using a sieve to obtain a coating liquid.

Using this coating solution, a conductive resin coating layer was formed on an aluminum cylindrical tube having an outer diameter of 16 mm by a spray method, and subsequently a 150 ° C., 30 ° C.
For 1 minute to cure, and the developer carrier S-1 shown in Table 1
(Ra = 1.23) was produced.

(Production Example 1 of Developer) A distillation column, a stirrer,
300 parts of xylene was charged into a reaction vessel equipped with a thermometer. Next, nitrogen gas is introduced into the container while stirring, and 30
After purging with nitrogen for minutes, the temperature was raised and refluxed.

Under the reflux, 90 parts of styrene, 10 parts of n-butyl acrylate and 0.35 part of monobutyl maleate are added and stirred while flowing a nitrogen gas. Next, a solution of 4 parts of di-tert-butyl peroxide dissolved in 10 parts of xylene was added dropwise over 1 hour. The polymerization was completed by holding for 5 hours to obtain a styrene-acrylic resin (binder resin B-1 for toner).

100 parts of binder resin for toner (B-1) 100 parts of magnetic iron oxide particles 4 parts of polypropylene 2 parts of charge control agent (Formula 2-1) 2 parts of the above mixture heated to 130 ° C. The mixture was melt-kneaded with a shaft extruder, and the cooled kneaded material was roughly pulverized by a hammer mill, and the coarsely pulverized product was finely pulverized by a jet mill.

The obtained finely pulverized product was classified by a fixed wall type air classifier to produce a classified powder. Furthermore, the obtained classified powder is
The ultrafine powder and the coarse powder were strictly classified and removed simultaneously by a multi-segmentation classifier utilizing the Coanda effect (Elbow jet classifier manufactured by Nippon Mining Co., Ltd.) to obtain a toner having a weight average diameter (D ₄ ) of 5.5 μm. (MI ₁₂₅ = 1.8 g / 10 min).

100 parts of the above toner and 1.4 parts of oil-treated silica were added and mixed with a Henschel mixer to obtain a developer T-1 shown in Table 2.

[Example 2] The developer carrier was the same as that of Example 1
-1 was used.

(Production Example 2 of Developer) Distillation tower, stirrer,
Acrylonitrile 180 was placed in a reaction vessel equipped with a thermometer.
Parts, butadiene 160 parts, sodium oleate 5 parts,
1 part of potassium persulfate and 200 parts of distilled water were charged. Next, nitrogen gas was introduced into the vessel while stirring, and the atmosphere was replaced with nitrogen for 30 minutes, and then the temperature was raised to 40 ° C. After holding for 24 hours to complete the polymerization, washing with methanol, acrylonitrile-
A butadiene resin (binder resin B-2 for toner) was obtained.

100 parts of binder resin for toner (B-2) 80 parts of magnetic iron oxide particles 8 parts of polyethylene 4 parts of charge control agent (formula 2-2) 4 parts of the above mixture heated to 100 ° C. The mixture was melt-kneaded with a shaft extruder, and the cooled kneaded material was roughly pulverized by a hammer mill, and the coarsely pulverized product was finely pulverized by a jet mill.

The obtained finely pulverized particles were classified by a fixed wall type air classifier to produce a classified powder. Furthermore, the obtained classified powder is
Ultrafine powder and coarse powder were simultaneously strictly classified and removed by a multi-division classifier utilizing the Coanda effect (Elbow Jet Classifier manufactured by Nippon Steel Mining Co., Ltd.) to obtain a toner having a weight average diameter (D ₄ ) of 10.1 μm. (MI ₁₂₅ = 28 g / 10 min).

100 parts of the toner and 0.6 parts of oil-treated silica were added and mixed with a Henschel mixer to obtain a developer T-2 shown in Table 2.

[Embodiment 3] The developer carrier is the same as that of the embodiment 1
-1 was used.

(Production Example 3 of Developer) Distillation tower, stirrer,
A reaction vessel equipped with a thermometer was charged with 1000 parts of sebacic acid and 650 parts of hexamethylene glycol, and then nitrogen gas was introduced into the vessel while stirring, followed by purging with nitrogen for 30 minutes, and then the temperature was raised. The reaction was stopped when the amount of distilled water reached 150 ml, and the reaction system was cooled to room temperature to obtain a polyester resin (binder resin B-3 for toner).

A toner of 7.4 μm was obtained in the same manner as in Example 2 except that the amount of wax was changed to 12 parts by using the binder resin B-3 for toner and the charge control agent (formula 4) (MI ₁₂₅ =
33 g / 10 min).

100 parts of the above toner and 1.1 parts of oil-treated silica were added and mixed with a Henschel mixer to obtain a developer T-3 shown in Table 2.

Example 4 (Production Example 2 of Developer Carrier) Plating with copper and silver
Using MA particles (34 μm, 1.54 g / cm ³ )
In the same manner as in Example 1 except that the conductive carbon black was eliminated, the developer carrier S-2 (Ra =
1.81).

The developer used was T-1 of Example 1.

Example 5 (Production Example 3 of Developer Carrier) A coal-based Burk mesophase bitch of 3 μm or less was put on 100 parts of a 10 μm spherical phenol resin using a Raikai machine (automatic mortar, manufactured by Ishikawa Industries). The spherical conductive carbon particles J-3 obtained by graphitizing by uniformly coating 14 parts of the powder and then performing heat stabilization treatment in an oxidizing atmosphere and then firing at 2600 ° C.
I got

The developer carrier S-3 (Ra = 1.0) shown in Table 1 was used in the same manner as in Example 1 except that graphite was eliminated by using acridine as the nitrogen-containing heterocyclic compound.
7) was obtained.

With respect to the developer, a developer T-4 shown in Table 2 was obtained in the same manner as in Example 1 except that the amount of wax was changed to 1 part.

[Embodiment 6] The developer carrying member is the same as that of the embodiment 1
-1 was used.

Regarding the developer, 100 parts of binder resin for toner (B-1) 100 parts of magnetic iron oxide particles 7 parts of higher alcohol-based wax (Mw900) 3 parts of charge control agent (Formula 2-1) 3 parts The mixture was melt-kneaded with a biaxial extruder heated to 130 ° C., and the cooled kneaded material was coarsely pulverized by a hammer mill, and the coarsely pulverized material was finely pulverized by a jet mill.

The obtained finely pulverized product was classified by a fixed wall type air classifier to produce a classified powder. Furthermore, the obtained classified powder is
Ultrafine powder and coarse powder were simultaneously strictly classified and removed by a multi-division classifier utilizing the Coanda effect (Nippon Mining Co., Ltd. Elbow Jet Classifier) to obtain a toner having a weight average diameter (D ₄ ) of 5.8 μm. (MI ₁₂₅ = 13.0 g / 10 min).

100 parts of the toner and 1.4 parts of oil-treated silica were added and mixed with a Henschel mixer to obtain a developer T-7 shown in Table 2.

[Embodiment 7] The developer carrying member is the same as that of the embodiment 1
-1 was used.

Regarding the developer, 100 parts of binder resin for toner (B-1) 100 parts of magnetic iron oxide particles 5 parts of higher alcohol-based wax (Mw700) 5 parts of charge control agent (formula 2-1) 3 parts The mixture was melt-kneaded with a biaxial extruder heated to 130 ° C., and the cooled kneaded material was coarsely pulverized by a hammer mill, and the coarsely pulverized material was finely pulverized by a jet mill.

The obtained finely pulverized particles were classified by a fixed wall type air classifier to produce a classified powder. Furthermore, the obtained classified powder is
Ultrafine powder and coarse powder were simultaneously strictly classified and removed by a multi-division classifier utilizing the Coanda effect (Elbow Jet Classifier manufactured by Nittetsu Mining Co., Ltd.) to obtain a toner having a weight average diameter (D ₄ ) of 6.7 μm. (MI ₁₂₅ = 10.0 g / 10 min).

100 parts of the toner and 1.2 parts of oil-treated silica were added and mixed with a Henschel mixer to obtain a developer T-8 shown in Table 2.

[Embodiment 8] The developer carrying member is the same as that of the embodiment 1
-1 was used.

Regarding the developer, 100 parts of binder resin for toner (B-1) 100 parts of magnetic iron oxide particles 5 parts of polypropylene (Mw3000) 3 parts of charge control agent (formula 2-1) 3 parts The mixture was melted and kneaded with a biaxial extruder heated to 130 ° C., and the cooled kneaded material was coarsely pulverized by a hammer mill, and the coarsely pulverized material was finely pulverized by a jet mill.

The obtained finely pulverized product was classified by a fixed wall type air classifier to produce a classified powder. Furthermore, the obtained classified powder is
Ultrafine powder and coarse powder were simultaneously strictly classified and removed by a multi-segmentation classifier utilizing the Coanda effect (Elbow jet classifier manufactured by Nippon Steel Mining Co., Ltd.) to obtain a toner having a weight average diameter (D ₄ ) of 6.5 μm. (MI ₁₂₅ = 3.8 g / 10 min).

100 parts of the toner and 1.2 parts of oil-treated silica were added and mixed with a Henschel mixer to obtain a developer T-9 shown in Table 2.

[Embodiment 9] The developer carrying member was the same as that of the embodiment 1
-1 was used.

Regarding the developer, 100 parts of binder resin for toner (B-1) 100 parts of magnetic iron oxide particles 7 parts of polyethylene (Mw900) 3 parts of charge control agent (formula 2-1) 3 parts The mixture was melted and kneaded with a biaxial extruder heated to 130 ° C., and the cooled kneaded material was coarsely pulverized by a hammer mill, and the coarsely pulverized material was finely pulverized by a jet mill.

The obtained finely pulverized product was classified by a fixed wall type air classifier to produce a classified powder. Furthermore, the obtained classified powder is
Ultrafine powder and coarse powder were simultaneously strictly classified and removed by a multi-segmentation classifier utilizing the Coanda effect (Elbow jet classifier manufactured by Nippon Steel Mining Co., Ltd.) to obtain a toner having a weight average diameter (D ₄ ) of 6.5 μm. (MI ₁₂₅ = 22.8 g / 10 min).

100 parts of the toner and 1.2 parts of oil-treated silica were added and mixed with a Henschel mixer to obtain a developer T-10 shown in Table 2.

Comparative Example 1 Spherical polystyrene particles (24.8 μm, 1.37 g) without the nitrogen-containing heterocyclic compound
/ Cm ³ ) in the same manner as in Example 1 to obtain a developer carrier S-4 (Ra = 1.34) shown in Table 1.

With respect to the developer, Example 2 was repeated except that commercially available polystyrene and a charge control agent (formula 4) were used as the binder resin.
In the same manner as described above, a 13.5 μm toner was obtained (MI ₁₂₅
= 0.2 g / 10 min).

100 parts of the toner and 0.5 parts of oil-treated silica were added and mixed with a Henschel mixer to obtain a developer T-5 shown in Table 2.

Comparative Example 2 A developer carrier S-5 (R) shown in Table 1 was prepared in the same manner as in Example 1 except that the untreated spherical phenol resin (18.9 μm) was used as the conductive spherical particles.
a = 1.38).

With respect to the developer, a 7.9 μm toner was obtained in the same manner as in Example 2 except that commercially available polyvinyl chloride and a charge control agent (formula 4) were used as the binder resin (MI ₁₂₅ =
42 g / 10 min).

100 parts of the above toner and 1.0 part of oil-treated silica were added and mixed with a Henschel mixer to obtain a developer T-6 shown in Table 2.

Next, the prepared magnetic toner was evaluated by the following method.

As an electrophotographic apparatus, as shown in FIG. 1, a commercially available LBP-A309GII made by Canon was used after improving the printing speed to 1.5 times (24 sheets / 1 minute: A4). The cartridge was modified from a Canon EP-B cartridge to a structure capable of replenishing toner. The developer carrier 3 and the silicone regulating blade 8 were mounted. The magnetic toner 13 was replenished under a high temperature and high humidity environment (32.5 ° C., 90 RH%) or under a low-temperature and low-humidity environment (10.0 ° C., 15 RH%), perform a printout test on 50,000 sheets continuously, and check whether the toner to be tested contaminates the developer carrier, the silicone regulating blade, and other members. Was visually checked. The following items were evaluated for the obtained images.

(1) Image Quality Sharpness: A character of "den" of about 2 mm square was printed out, and the level of sharpness of the character such as toner scattering around the character of "den" was evaluated by observation with an optical microscope. Rank 1: Sharp with little toner scattering around the character. Rank 2: Slight scattering of toner. Rank 3: toner scattering is large.

Dot reproducibility: An independent one-dot pattern was printed out, and the reproducibility of one dot was evaluated by observation with an optical microscope. Rank 1: The dots are faithfully reproduced. Rank 2: There is some disturbance in the image. Rank 3: The image is often disturbed and the reproducibility is poor.

(2) Image Density The image density was evaluated by maintaining the image density after printing 20,000 sheets on ordinary plain paper for copying (75 g / m ² ). The image density was measured by using a "Macbeth reflection densitometer" (manufactured by Macbeth Co., Ltd.) with respect to a printout image of a white background portion of a document having a density of 0.00.

(3) Rise The rise was evaluated based on the difference ΔD between the image density after printing 100 sheets and the initial density. Rank 1: rising very good (ΔD ≧ 0.10) Rank 2: good rising (0.04 <ΔD <0.1)
0) Rank 3: Bad start (ΔD ≧ 0.04)

(4) Stain Resistance of the Member The surface of the member such as the developer carrier and the silicone regulating blade after the endurance was observed by SEM, and the degree of toner contamination was evaluated according to the following criteria. Rank 1: Slight contamination is observed. Rank 2: Partial contamination is observed. Rank 3: Significant contamination is observed.

(5) Fixing Fixing was performed by applying a load of 50 g / cm ² , rubbing the fixed image with soft thin paper, and evaluating the reduction rate (%) of the image density before and after rubbing. Rank 1 (excellent): less than 5% Rank 2 (good): 5% or more and less than 10% Rank 3 (acceptable): 10% or more, less than 20% Rank 4 (bad): 20% or more

(6) Offset Resistance The offset resistance was evaluated by printing out a sample image having an image area ratio of about 5% and examining the degree of stain on the image after 20,000 sheets. Rank 1: good (almost no occurrence) Rank 2: practical use possible Rank 3: bad

Table 3 shows the evaluation results of the above (1) to (6).

[0174]

[Table 1]

[0175]

[Table 2]

[0176]

[Table 3]

[0177]

As described above, by combining the developer carrier of the present invention with the developer, the reproducibility of fine lines can be improved.
Provided is an image forming method which is excellent in gradation, maintains high image quality and high developability, does not cause toner contamination of a developer carrier or the like due to durability, and highly satisfies fixability and offset resistance. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an image forming apparatus used in an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Developing device 2 Developer container 3 Latent image carrier (photoreceptor) 4 Transfer means 5 Laser light or analog light 6 Developer carrier 7 Cleaning blade 8 Silicon regulating blade 11 Charging means 12 Bias applying means 13 Developer 14 Cleaning means Reference Signs List 15 magnetic field generating means 20 heating element 21 fixing roller 22 pressure roller

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Keita Nozawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Yoshihiro Ogawa 3-30-2 Shimomaruko 3-chome, Ota-ku, Tokyo Non Corporation

Claims (11)

[Claims] 1. A developer layer is formed on a developer carrier facing an electrostatic latent image carrier, and an electrostatic latent image carried on the electrostatic latent image carrier is transferred to the developer carrier. In the image forming method including the step of developing with the above developer, the developer carrier has at least a substrate and a coating layer covering the substrate, and the coating layer includes a binder resin, The developer contains at least conductive spherical particles and a nitrogen-containing heterocyclic compound dispersed in a binder resin, and the developer has a melt index MI ₁₂₅ (125 ° C.,
0.5 kg / 10 min to 35 g / 10
An image forming method, comprising: a toner having a minimum toner density. 2. The image forming method according to claim 1, wherein the nitrogen-containing heterocyclic compound has an imidazole compound. 3. The image forming method according to claim 1, wherein the conductive spherical particles include carbon particles. 4. The conductive spherical particles have a number average diameter of 0.1.
The image forming method according to claim 1, wherein the true density is 3 μm to 30 μm and the true density is 3 g / cm ³ or less. 5. The image forming method according to claim 1, wherein said coating layer further contains conductive fine particles. 6. The image forming method according to claim 1, wherein said coating layer further contains a lubricating substance. 7. The toner according to claim 1, wherein the toner has a melt index MI.
₁₂₅ (125 ° C, 5kg load) is 1.5g / 10min
The image forming method according to any one of claims 1 to 6, wherein the weight is from 30 to 30 g / 10 min. 8. The toner according to claim 1, wherein the toner has a melt index MI.
₁₂₅ (125 ° C, 5kg load) is 5.0g / 10min
The image forming method according to any one of claims 1 to 6, wherein the weight is from 25 to 10 g / 10 min. 9. The toner according to claim 1, wherein the toner contains a charge control agent, and the charge control agent contains an azo-based metal complex compound represented by the following formula (1). 2. The image forming method according to 1., Embedded image 10. The image forming method according to claim 9, wherein the charge control agent contains an azo-based iron complex compound represented by the following formula (2). Embedded image 11. The toner according to claim 1, wherein the toner contains a charge control agent, and the charge control agent contains a basic organometallic complex represented by the following formula (3). 2. The image forming method according to 1., Embedded image