JP2003323042A - Developer carrier, and developing device and process cartridge using developer carrier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developer carrier constituted so that the physical shape of its surface and the composition of material may not be changed even in the case of endurable service, stably electrifying toner over a long term and preventing soiling by toner and the charge-up of the toner. <P>SOLUTION: The developer carrier carrying developer for making an electrostatic latent image carried on an electrostatic latent image carrier visualizable has at least base substance and a resin coating layer formed on the surface of the base substance, and the resin coating layer incorporates at least graphitized particles whose graphitization degree p (002) is 0.20 to 0.95, and whose indentation hardness value HUT[68] is 15 to 60. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer carrier used in a developing device for developing and visualizing a latent image formed on an image carrier such as an electrophotographic photoreceptor or an electrostatic recording derivative. Regarding the body Further, the present invention relates to a developing device and a process cartridge using the above developer carrier.

[0002]

2. Description of the Related Art Conventionally, a large number of electrophotographic methods are known, but generally, a photoconductive material is used, and various means are used to electrically connect an electrostatic latent image holding member (photosensitive drum) to an electrical surface. After forming a latent image, the electrostatic latent image is developed with a developer (toner) to make it a visible image, and after transfer of the toner image to a transfer material such as paper, if necessary, by heat or pressure. The toner image is fixed on the transfer material to obtain a copy.

The developing method in electrophotography is mainly divided into a one-component developing method and a two-component developing method. In recent years, a developing device using a one-component developing system is often used because it is necessary to reduce the size of a copying device in order to reduce the weight and size of an electrophotographic device.

Unlike the two-component developing method, the one-component developing method does not require carrier particles such as glass beads and iron powder.
The developing device itself can be made smaller and lighter. On the other hand, in the two-component developing method, it is necessary to keep the toner concentration in the developer constant, so that a device for detecting the toner concentration and supplying a required amount of toner is required. Therefore, also in this case, the developing device becomes large and heavy. In the one-component developing method, such an apparatus is not necessary, and it is preferable because it can be made small and light.

As a developing device using the one-component developing system, an electrostatic latent image is formed on the surface of a photosensitive drum as an electrostatic latent image holding member, friction between a developer carrying member (developing sleeve) and toner, and Alternatively, a positive or negative charge is applied to the toner by friction between the toner and the developer layer thickness regulating member for regulating the toner coating amount on the developing sleeve. Then, the charged toner is thinly applied onto the developing sleeve and conveyed to the developing area where the photosensitive drum and the developing sleeve face each other, and the toner flies and adheres to the electrostatic latent image on the surface of the photosensitive drum in the developing area. What develops and visualizes an electrostatic latent image as a toner image is known.

However, when such a one-component developing method is used, it is difficult to adjust the charging of the toner, and although various measures have been taken with the toner, the uneven charging of the toner and the durability stability of the charging are involved. The problem has not been completely resolved.

In particular, while the developing sleeve is repeatedly rotated, the charge amount of the toner coated on the developing sleeve becomes too high due to the contact with the developing sleeve, and the toner is reflected by the surface of the developing sleeve. A so-called charge-up phenomenon, in which the toner attracts each other and becomes immobile on the surface of the developing sleeve and does not move from the developing sleeve to the latent image on the photosensitive drum, is likely to occur particularly in low humidity. When such a charge-up phenomenon occurs, the toner in the upper layer is less likely to be charged and the developing amount of the toner decreases,
Problems such as thin line images and low image density of solid images occur. Further, a so-called blotch phenomenon occurs in which toner that is not properly charged due to charge-up becomes defective in regulation and flows out onto the sleeve, resulting in spot-like or wavy unevenness.

Further, since the toner layer forming states of the image portion (toner consuming portion) and the non-image portion are changed and the charging states are different, for example, a solid image having a high image density is once developed on the developing sleeve. When the position comes to the developing position during the next rotation of the developing sleeve and the halftone image is developed, a so-called sleeve ghost phenomenon in which a trace of a solid image appears on the image easily occurs.

Further, recently, in order to digitize the electrophotographic apparatus and further improve the image quality, the particle size and the particle size of the toner have been reduced. For example, in order to improve resolution and character sharpness and faithfully reproduce a latent image, it is general to use a toner having a weight average particle diameter of about 5 to 12 μm. Further, from the viewpoint of ecology and for the purpose of further reducing the weight and size of the apparatus, the transfer efficiency of the toner has been improved in order to reduce the waste toner. For example,
BET with a transfer efficiency improver having an average particle size of 0.1 to 3 μm
By incorporating a hydrophobic silica fine powder having a specific surface area of 50 to 300 m ² / g into the toner, the volume resistance of the toner is reduced, and the transfer efficiency is improved by forming a thin film layer of the transfer efficiency improver on the photosensitive drum. In addition to the above, a method is known in which the transfer efficiency is improved by further sphericalizing the toner itself by a mechanical impact force.

Further, the toner fixing temperature tends to be lowered for the purpose of shortening the first copy time and saving power. Under such circumstances, the toner especially under low temperature and low humidity is more likely to electrostatically adhere to the developing sleeve because the amount of electric charge per unit mass increases, and the toner under high temperature and high humidity can be physically removed from the outside. Since it uses a material that has high power and is easily fluidized, the quality of the material is easily changed, and the sleeve is liable to be contaminated by the toner and the sleeve is easily fused.

As a method for solving such a phenomenon, Japanese Patent Laid-Open Nos. 02-105181 and 03-036573 are available.
No. 0, etc. proposes a method of using a developing sleeve, in which a coating layer formed by dispersing conductive fine powder such as crystalline graphite and carbon in a resin, on a metal substrate is used in a developing device. . It is recognized that by using this method, the above-mentioned phenomenon is significantly reduced.

However, in this method, when a large amount of the above-mentioned powder is added, it is good against charge-up and sleeve ghost, but the proper charge imparting ability to the toner is insufficient, and especially at high temperature and high temperature. It is difficult to obtain a sufficient image density in a humid environment. Furthermore, when a large amount of the above powder is added, the coating layer becomes brittle and easily scraped, and the surface shape becomes non-uniform, and the surface roughness and surface composition of the coating layer change when durable use is advanced. As a result, poor toner conveyance and uneven charging of the toner are likely to occur.

When the coating layer in which the crystalline graphite is dispersed is used, the surface of the coating layer has lubricity due to the scaly structure of the crystalline graphite, so that charge-up and charge-up are prevented. Sufficiently effective against sleeve ghost, but the surface shape of the coating layer is non-uniform due to the flaky shape, and the hardness of crystalline graphite is low. It is liable to wear or detach itself, and when it is used for a long time, the surface roughness and surface composition of the coating layer change, resulting in poor toner conveyance and uneven charging of the toner. It is easy to happen.

On the other hand, when the amount of the conductive fine powder added to the coating layer formed on the metal substrate of the developing sleeve is small, the effect of the conductive fine powder such as crystalline graphite and carbon is small, The problem remains that countermeasures against charge-up and sleeve ghosts are insufficient.

Further, in Japanese Patent Application Laid-Open No. 03-200986, a developing sleeve in which a conductive coating powder in which a conductive fine powder such as crystalline graphite and carbon is dispersed in a resin and spherical particles are dispersed is provided on a metal substrate. Is proposed. In this developing sleeve, the abrasion resistance of the coating layer is improved to some extent, the shape of the coating layer surface is made uniform, and the change in surface roughness due to durable use is relatively small. Can be stabilized and the charge of the toner can be made uniform to some extent, and there is no problem with sleeve ghost, image density, image density unevenness, etc.
The image quality tends to be stable. However, even this developing sleeve is insufficient for stabilizing the charge controllability to the toner quickly and uniformly and the ability to impart appropriate charge to the toner. In terms of wear resistance, changes in the roughness and roughness of the surface of the coating layer caused by wear or loss of spherical particles or crystalline graphite in the coating layer in the developing sleeve after long-term durable use. Unevenness of
As a result, toner contamination and toner fusion of the coating layer occur, and in such a case, the charging of the toner becomes unstable, which causes a defective image.

In JP-A-08-240981, the spherical particles dispersed in the conductive coating layer are spherical particles having a low specific gravity and conductivity, whereby the conductive spherical particles are uniformly distributed in the conductive coating layer. Are dispersed, the abrasion resistance of the coating layer and the shape of the surface of the coating layer are made uniform, and the uniform charge imparting property to the toner is improved. A developing sleeve has been proposed which can suppress the adhesion. However, even this developing sleeve is not perfect in terms of its ability to impart a rapid and uniform charge to the toner and its appropriate ability to impart a charge to the toner.
In addition, in wear resistance, even in long-term durable use, conductive particles such as crystalline graphite are easily worn or fallen off from a portion of the coating layer surface where conductive spherical particles do not exist. The abrasion of the coating layer is promoted from the worn and dropped portion, resulting in toner contamination and toner fusion, which makes the toner charging unstable and causes an image defect.

[0017]

The present invention has been made in view of the above problems, and does not cause problems such as density reduction, image density unevenness, sleeve ghost, and fog even under different environmental conditions. An object of the present invention is to provide a developer carrying member, a developing device using the developer carrying member, and a process cartridge, which are capable of stably obtaining a high-quality image having a uniform image density and a high image density.

Further, according to the present invention, the toner adhesion to the surface of the developer carrying member, which appears when an image is formed by using a toner having a small particle diameter or a spherical toner, is reduced, so that the toner becomes non-uniform. An object of the present invention is to provide a developer carrying member, a developing device and a process cartridge using the developer carrying member, which can control the charging and quickly give a proper charging to the toner.

Further, the present invention is a developer carrier which is resistant to deterioration of the resin coating layer on the surface of the developer carrier due to repeated copying or durable use, has high durability, and can obtain stable image quality. An object of the present invention is to provide a developing device and a process cartridge using the developer carrying member.

Further, according to the present invention, even in continuous copying for a long period of time, the toner on the developer carrying member is quickly and uniformly imparted with an appropriate charge, and a stable charge is always imparted without causing charge-up. Provided are a developer carrier capable of obtaining a high-quality image having a uniform density without image density reduction, density unevenness, and fog during durable use, and a developing device and a process cartridge using the developer carrier. Is an issue.

[0021]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that the resin coating layer on the surface of the developer carrying member has a graphitization degree and an indentation hardness value within a specific range. By having the constitution in which the graphitized particles having are dispersed in the resin, a resin coating layer having a uniform surface shape and lubricity is formed, and the graphitized particles are prevented from being worn or detached from the surface of the resin coating layer. I found it difficult to wake up. Also,
By configuring the developer carrier as described above, the graphitized particles are exposed again from the resin coating layer even when the resin coating layer is worn, so that the surface coating layer of the developer carrier can be formed even when a large number of images are printed. It was found that the roughness, the uniformity of the surface shape, and the change in the material composition of the surface can be suppressed. Further, the present inventor has found that the resin coating layer containing the graphitized particles does not cause toner contamination or toner charge-up, and has an effect of quickly and uniformly imparting an appropriate amount of charge to the toner. It was

That is, the present invention is as follows. (1) A developer carrying body carrying a developer for visualizing an electrostatic latent image carried on an electrostatic latent image carrying body, wherein the developer carrying body is formed on a substrate and a surface of the substrate. A graphite having a degree of graphitization p (002) of 0.20 to 0.95 and an indentation hardness value HUT [68] of 15 to 60. A developer carrying body, characterized in that it contains at least activated particles. (2) The coefficient of friction μs of the resin coating layer is 0.10 ≦ μs
The developer carrier according to (1), wherein ≦ 0.35. (3) The developer carrier according to (1) or (2), wherein the graphitized particles are obtained by graphitizing mesocarbon microbead particles or bulk mesophase pitch particles. (4) The number average particle diameter of the graphitized particles is 0.5 to 25 μm.
m is the developer carrying member according to any one of (1) to (3). (5) To a developing area facing the electrostatic latent image carrier, which has a developer container for containing the developer and a developer carrier for carrying the developer contained in the developer container in layers. A developing device for transporting the carried developer, and developing and visualizing the electrostatic latent image carried on the electrostatic latent image carrier by the carried developer. Is a developer carrying member according to any one of (1) to (4). (6) Image formation for forming an image by visualizing the electrostatic latent image formed on the electrostatic latent image carrier with a developer to form a toner image, and transferring the toner image to a transfer material. A process cartridge detachably attached to an apparatus main body, for forming an electrostatic latent image carrier for carrying an electrostatic latent image and the electrostatic latent image with a developer to form a developed image. Developing means, (i) charging means for charging the electrostatic latent image carrier, (ii) latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, (iii) the developed image A transfer means for transferring the toner to a transfer material, and (iv) at least one means selected from a cleaning means for removing the transfer residual developer on the electrostatic latent image carrier and integrally supported with the developing means. And the developing means has a developer container for containing a developer, 1) a process cartridge characterized by having a one of the developer carrying member to (4).

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to preferred embodiments. First, the developer carrier of the present invention will be described.

The developer carrying member of the present invention is a developer carrying member carrying a developer for visualizing the electrostatic latent image carried on the electrostatic latent image carrying member, and is provided on the substrate and the surface of the substrate. And a formed resin coating layer. Further, the developer carrier of the present invention has a graphitization degree p (00
2) is 0.20 to 0.95 and the indentation hardness value H
It is characterized by containing at least graphitized particles having a UT [68] of 15 to 60.

Specific graphitization degree p (002) as described above
And by including graphitized particles having an indentation hardness value HUT [68] in the resin coating layer constituting the developer carrying member, a uniform surface roughness is maintained on the coating layer surface and at the same time, the coating layer surface. The surface roughness of the coating layer does not change much even when it is worn, and the resin coating layer is excellent in lubricity and uniform conductivity, which makes it difficult for developer contamination and developer fusion to occur. You can Further, when the above graphitized particles are contained in the resin coating layer constituting the developer carrying member, they also have the effect of enhancing quick and uniform chargeability to the toner contained in the developer.

The above graphitization degree p (002) means Fra
It is called the p value of nklin and is a value obtained by using the following formula (1) by measuring the lattice spacing d (002) obtained from the X-ray diffraction diagram of graphite.

[0027]

[Number 1] d (002) = 3.440-0.086 (1 -p (002) 2) (1) The p (002) value, of the stacking hexagonal mesh plane of the carbon, the proportion of disorderly portions , P (0
02) The smaller the value, the greater the degree of graphitization.

The above-mentioned graphitized particles are described in JP-A-02-1051.
No. 81, Japanese Patent Application Laid-Open No. 03-036570, etc., the bone agent such as coke used in the coating layer on the surface of the developer carrier is fixed by tar pitch or the like, and then molded 1
2500 ~ 30 after firing at about 000 ~ 1300 ℃
The raw material and the manufacturing process are different from artificial graphite obtained by graphitization at about 00 ° C. or crystalline graphite made of natural graphite. The graphitized particles used in the present invention have a slightly lower graphitization degree than the crystalline graphites disclosed in the above-mentioned publications, but have high conductivity and lubricity similar to the crystalline graphites. Further, the graphitized particles used in the present invention are different in that the shape of crystalline graphite is flake-like or acicular, and the shape of the particles is approximately spherical, and the hardness of the particles themselves is relatively high. It is a feature. Therefore, the graphitized particles having the above-mentioned characteristics are easily dispersed uniformly in the resin coating layer, so that the surface of the coating layer can be provided with uniform surface roughness and abrasion resistance. In addition to this, since the shape of the graphitized particles themselves is difficult to change, the coating resin component in the resin coating layer is scraped off, or even if the particles themselves fall off due to the influence, the particles are re-generated from the resin layer. It may be protruding or exposed,
The change in the surface shape of the resin coating layer can be suppressed to a small level.

Further, when the above graphitized particles are contained in the resin coating layer on the surface of the developer carrying member, the charge-up of the toner does not occur on the surface of the coating layer, and it is more than in the case of using the conventional crystalline graphite. It is possible to improve the ability to quickly and uniformly give triboelectrification to the toner.

The degree of graphitization p (002) of the graphitized particles used in the present invention is 0.20 to 0.95. This p
(002) is preferably 0.25 to 0.75, and more preferably 0.25 to 0.70.

When p (002) exceeds 0.95,
Although the resin coating layer is excellent in abrasion resistance, the conductivity and lubricity may be deteriorated to cause charge-up of the toner, and the image quality such as sleeve ghost, fog, and image density is likely to deteriorate. Furthermore, when an elastic blade is used in the developing process, blade scratches may occur, and streaks and uneven density are likely to occur in the image. On the other hand, p
When (002) is less than 0.20, the abrasion resistance of the graphitized particles is deteriorated, so that the abrasion resistance of the coating layer surface, the mechanical strength of the resin coating layer, and the quick and uniform charge imparting property to the toner. Will decrease.

Further, the graphitized particles used in the present invention are
The indentation hardness value HUT [68] is 15 to 60. The indentation hardness value HUT [68] is preferably 20 to 55, more preferably 25 to 50.
Is.

When the indentation hardness value HUT [68] is less than 15, the abrasion resistance and mechanical strength of the resin coating layer and the quick and uniform charge imparting property to the toner tend to be deteriorated. On the other hand, when the indentation hardness value HUT [68] is more than 60, the abrasion resistance of the resin coating layer is excellent, but the conductivity and lubricity may be deteriorated to cause the charge-up of the toner. Image quality such as ghost, fog, and image density easily deteriorates.

Indentation hardness value HUT [6 in the present invention
8] is an indentation hardness value HUT [68] measured with a microhardness meter MZT-4 manufactured by Akashi Co., Ltd. using a triangular pyramid diamond indenter having a face angle with respect to the axis of 68 degrees. It is expressed by equation (2).

[0035]

[Equation 2] Indentation hardness value HUT [68] = K × F / (h2) ² (2) [where K: coefficient, F: test load, h2: maximum indentation depth of indenter] Also, since it can be measured with a load smaller than other hardness and the like, and a material having elasticity and plasticity can obtain hardness including elastic deformation and plastic deformation, it is preferably used.

The specific measuring method is as follows. As a sample prepared for measurement, a surface of the resin coating layer of the developer bearing member was smoothed with a # 2000 polishing tape so that the graphitized particles in the resin coating were exposed.

Indentation hardness value HUT [6 of graphitized particles
8] is a graphitized particle having a size of 10 μm or more exposed on the surface of the coating resin layer after the sample is fixed and polished, and the indenter is aimed at the measurement to measure different graphitized particles of the same sample. Is measured at 10 or more points, and the average value is determined as the indentation hardness value HUT [68] of the graphitized particles.

The main measurement conditions are as follows. TE
The measurement is performed in ST MODE A. TEST MODE
A is for setting a load to be pushed into the sample for measurement, and there are two loads to be added: an initial load called a reference load F0 and a test load F1 which is a final load. During measurement, after the indenter contacts the sample, a reference load is applied to the sample, and the indenter is pushed into the sample by the load of the reference load. The point where the indenter is pushed in by the standard load is set as the zero point of the indentation depth, the test load is applied to the indenter, the set holding time and the test load are held, and the indenter depth h2 after holding the test load is The maximum indentation depth) is required. The indentation depth value HUT [68] is obtained from the following equation (3).

[Equation 3] Indentation hardness value HUT [68] = K × [(F1) ^0.5 − (F0) ^0.5 ] ² / (h2) ² (3) [where F1: test load (mN), F0: reference load] (M
N), h2: Indentation depth (μ of the indenter after holding the test load)
m), K: coefficient (K = 2.972, triangular pyramid indenter, 68 °)
SI unit system coefficient using)] Test load F1: 49.0 mN Reference load F0: 4.9 mN Pushing speed V: 1.00 μm / sec Holding time T2: 5 sec Unloading time T3: 5 sec Maximum of test load and indenter The indentation depth is preferably within a range not affected by the surface roughness of the coating layer surface and not affected by the base substrate, and in the present invention, the maximum indentation depth of the test load indenter is 1 to 2 μm. The test load is measured to a certain degree.

Further, the graphitized particles used in the present invention are
The average circularity SF-1 that is the average value of the circularity obtained by the following formula (4) is preferably 0.64 or more,
It is more preferably 0.66 or more, still more preferably 0.68 or more.

When the average circularity SF-1 is less than 0.64, the dispersibility of the graphitized particles in the resin coating layer decreases and the surface roughness of the resin coating layer becomes nonuniform. However, it is not preferable in terms of quick and uniform charging of the toner and abrasion resistance and strength of the resin coating layer.

In the present invention, the average circularity SF-1 of the graphitized particles means the average value of the circularity obtained from the following equation (4).

[0042]

Equation 4] circularity = (4 × A) / { (ML) 2 × π} (4) [ wherein, ML represents the Pythagorean method maximum length of a particle projected image, A represents an area of particle projected image . In the present invention, as a specific method for obtaining the above-mentioned average circularity SF-1, the graphitized particle projection image magnified by the optical system is taken into an image analyzer, and the circularity of each particle is calculated. It is calculated by calculating the values and averaging them.

In the present invention, the reliability is obtained as an average value, and the circularity is measured only within a particle range having an equivalent circle diameter of 2 μm or more, which has a great influence on the characteristics of the resin coating layer. There is. Further, in order to obtain the reliability of these values, the number of measured particles is about 3000 or more, preferably 50 or more.
00 or more are measured.

A multi-image analyzer (manufactured by Beckman Coulter, Inc.) is a specific measuring device that can efficiently analyze the circularity of many graphitized particles.

The multi-image analyzer is a combination of a particle size distribution measuring device using an electric resistance method, with a function of photographing a particle image by a CCD camera and a function of analyzing the photographed particle image. In detail, the measurement particles uniformly dispersed in the electrolyte solution by ultrasonic waves, etc., is detected by the change in electric resistance when the particles pass through the aperture of Multisizer, which is a particle size distribution measuring device by the electric resistance method,
In synchronization with this, a strobe is emitted and a CCD camera captures a particle image. This particle image is taken into a personal computer, binarized and then image-analyzed.

The graphitized particles used in the present invention preferably have a number average particle diameter of 0.5 to 25 μm,
More preferably, it is 20 μm.

When the number average particle size of the graphitized particles is less than 0.5 μm, the effect of imparting uniform roughness and lubricity to the surface of the resin coating layer and the effect of enhancing the charge imparting property to the toner are small, and the effect on the toner is small. It is not preferable because rapid and uniform charging becomes insufficient, and toner is charged up due to abrasion of the coating layer, toner contamination and toner fusion occur, and ghost and image density are easily deteriorated. Also,
When the number average particle diameter exceeds 25 μm, the roughness of the surface of the coating layer becomes too large, which makes it difficult to sufficiently charge the toner and reduces the mechanical strength of the coating layer. Not preferable.

The adjustment of the number average particle size of the graphitized particles depends on the raw material used and the manufacturing method, but the means for controlling the particle size of the raw material before graphitization by pulverization or classification, or further classification after graphitization Can be controlled by.

As a method for obtaining graphitized particles having the above graphitization degree p (002) and indentation hardness value, the following methods are preferable, but not limited to these methods.

As a method for obtaining particularly preferred graphitized particles used in the present invention, particles having optical anisotropy such as mesocarbon microbeads and bulk mesophase pitch as raw materials and having a single phase are used. It is preferable to graphitize by using to improve the graphitization degree of the graphitized particles and maintain an appropriate hardness and a substantially spherical shape while maintaining lubricity.

The optical anisotropy of the above-mentioned raw materials arises from the lamination of aromatic molecules, and its ordering is further developed by the graphitization treatment to obtain graphitized particles having a high degree of graphitization. .

When the above-mentioned bulk mesophase pitch is used as the raw material for obtaining the graphitized particles used in the present invention, a material that softens and melts under heating is used to obtain spherical graphitized particles having a high degree of graphitization. Preferred for.

A typical method for obtaining the above-mentioned bulk mesophase pitch is, for example, by extracting β-resin from coal tar pitch or the like by solvent fractionation, and subjecting this to hydrogenation and heavy treatment to obtain bulk mesophase pitch. Is a way to get. In the above method, the bulk mesophase pitch may be obtained by finely pulverizing after the heavy treatment and then removing the solvent-soluble component with benzene or toluene.

The bulk mesophase pitch preferably has a quinoline-soluble content of 95 wt% or more. 95w
If less than t% is used, the inside of the particles is less likely to be liquid-phase carbonized and solid-phase carbonized to leave the particles in a crushed state, making it difficult to obtain spherical particles.

A method of graphitizing the bulk mesophase pitch obtained as described above will be described below. First, the bulk mesophase pitch is finely pulverized to 2 to 25 μm and heat-treated at about 200 to 350 ° C. in air to slightly oxidize it. By this oxidation treatment,
Only the surface of the bulk mesophase pitch is infusibilized, and melting and fusion during the graphitization firing in the next step are prevented. The oxidized mesophase pitch has an oxygen content of 5
It is preferably ˜15 wt%. Oxygen content is 5w
If it is less than t%, fusion of particles during heat treatment is severe, which is not preferable, and if it exceeds 15 wt%, the inside of the particles is also oxidized, and it is difficult to obtain graphitized and spherical particles in a crushed shape.

Next, the bulk mesophase pitch which has been subjected to the above-mentioned oxidation treatment is treated under an inert atmosphere of nitrogen, argon or the like.
Carbonization is performed by primary firing at about 800 to 1200 ° C, followed by secondary firing at about 2000 to 3500 ° C to obtain the desired graphitized particles.

Typical methods for obtaining mesocarbon microbeads, which is another preferable raw material for obtaining the graphitized particles used in the present invention, will be exemplified below. First of all, use 3 types of heavy coal oil or heavy petroleum oil.
Heat treatment is performed at a temperature of 00 to 500 ° C., and polycondensation is performed to produce crude mesocarbon microbeads. Obtained by separating the mesocarbon microbeads by subjecting the obtained reaction product to treatments such as filtration, static sedimentation, and centrifugation, washing with a solvent such as benzene, toluene, xylene, and further drying. .

When graphitizing the obtained mesocarbon microbeads, it is necessary to first mechanically disperse the dried mesocarbon microbeads by a gentle force that does not destroy the combined mesocarbon microbeads. It is preferable for prevention and for obtaining a uniform particle size.

The mesocarbon microbeads which have been subjected to the primary dispersion are primarily calcined and carbonized at a temperature of 200 to 1500 ° C. in an inert atmosphere. It is preferable to mechanically disperse the carbide that has undergone the primary calcination with a mild force that does not destroy the carbide, in order to prevent coalescence of the particles after graphitization and to obtain a uniform particle size.

The carbide which has undergone the primary firing is subjected to a secondary firing at about 2000 to 3500 ° C. in an inert atmosphere to obtain desired graphitized particles.

The graphitized particles obtained from any of the above raw materials, regardless of which manufacturing method is used,
To make the particle size distribution uniform to some extent by classification,
It is preferable in order to make the surface shape of the resin coating layer uniform.

Further, in any of the raw material producing methods for producing graphitized particles, the graphitizing firing temperature is from 2000 to 2,000.
It is preferably 3500 ° C., and 2300 to 3200
More preferably, the temperature is ° C.

When the baking temperature for graphitization is 2000 ° C. or less, the graphitization degree of the graphitized particles is insufficient, and the conductivity and lubricity may be deteriorated to cause charge-up of the toner. Image quality such as ghost, fog, and image density easily deteriorates. Furthermore, when an elastic blade is used, blade scratches may occur, and streaks and uneven density are likely to occur in an image. Also, the firing temperature is 3500
In the case of ℃ or more, the graphitization degree of the graphitized particles may be too high, therefore the hardness of the graphitized particles is reduced, the wear resistance of the coating layer surface due to the deterioration of the wear resistance of the graphitized particles,
The mechanical strength of the resin coating layer and the property of imparting charge to the toner are likely to decrease.

In the present invention, the coefficient of friction μs of the resin coating layer of the developer carrying member is preferably 0.10 ≦ μs ≦ 0.35, and more preferably 0.12 ≦ μs ≦ 0.30. . If the coefficient of friction μs of the resin coating layer is less than 0.1, the developer transportability may be deteriorated, and sufficient image density may not be obtained. Friction coefficient of resin coating layer μ
When s exceeds 0.35, toner charge-up is likely to occur, toner contamination and toner fusion occur on the resin coating surface, and image quality such as sleeve ghost, fog, and image density is easily deteriorated. Become.

The range of the friction coefficient μs of the resin coating layer as described above can be obtained by dispersing the graphitized particles used in the present invention in the coating resin layer.

The friction coefficient μs is measured by fixing the developer carrier at a horizontal position and contacting a brass (hard chrome treated) slider of Tribogear Muse (TYPE: 94i) made by HEIDON with its longitudinal direction. . Further, the value of the friction coefficient μs is obtained by measuring 10 points by appropriately changing the measurement place on the surface of the developer carrying member and averaging the values.

As the coating resin material for the resin coating layer which constitutes the developer carrying member of the present invention, it is possible to use a known resin which has been generally used for the resin coating layer of the developer carrying member. . For example, styrene resin, vinyl resin, polyether sulfone resin, polycarbonate resin, polyphenylene oxide resin, polyamide resin,
Thermoplastic or thermosetting resin such as thermoplastic resin such as fluororesin, fibrin resin, acrylic resin, epoxy resin, polyester resin, alkyd resin, phenol resin, melamine resin, polyurethane resin, urea resin, silicone resin, polyimide resin, etc. Resin or the like can be used. Among them, those with releasability such as silicone resin, fluororesin, polyether sulfone, polycarbonate,
Polyphenylene oxide, polyamide, phenol,
Those having excellent mechanical properties such as polyester, polyurethane, styrene resin, and acrylic resin are more preferable.

In the present invention, the volume resistance of the resin coating layer of the developer carrying member is preferably 10 ⁻² to 10 ⁵ Ω · cm, more preferably 10 ⁻² to 10 ⁴ Ω · cm. When the volume resistance of the resin coating layer exceeds 10 ⁵ Ω · cm, toner charge-up is likely to occur and the resin coating layer is likely to be contaminated with toner.

In the present invention, in order to adjust the volume resistance of the resin coating layer to the above value, other conductive fine particles may be dispersedly contained in the resin coating layer in combination with the above graphitized particles. .

The number average particle size of the conductive fine particles is preferably 1 μm or less, more preferably 0.01 to.
It is preferably 0.8 μm. When the number average particle diameter of the conductive fine particles to be dispersedly contained in the resin coating layer in combination with the graphitized particles exceeds 1 μm, it becomes difficult to control the volume resistance of the resin coating layer to a low level, resulting in toner charge-up. Toner contamination is likely to occur.

Examples of the conductive fine particles that can be used in the present invention include 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 and nickel, graphite,
Examples include inorganic fillers such as metal fibers and carbon fibers.

The effect of the present invention is further promoted when spherical particles that impart irregularities to the surface of the resin coating layer are further used in the resin coating layer constituting the developer carrying member of the present invention and dispersed therein. preferable.

The spherical particles maintain a uniform surface roughness on the surface of the resin coating layer of the developer carrying member and at the same time improve the abrasion resistance, and even when the surface of the resin coating layer is worn, the surface roughness of the coating layer is increased. There is little change in the degree, and there is an effect of making it difficult to cause toner contamination or toner fusion on the surface of the resin coating layer.

The spherical particles used in the present invention have a number average particle diameter of 1 to 30 μm, preferably 2 to 20 μm.

When the number average particle diameter of the spherical particles is less than 1 μm, the effect of imparting uniform roughness to the surface and the effect of enhancing abrasion resistance are small, and the uniform charging of the developer becomes insufficient, and the resin is not sufficiently charged. Toner charge up due to abrasion of coating layer,
Toner contamination and toner fusion occur, resulting in worse ghost,
It is not preferable because the image density is likely to decrease. When the number average particle diameter exceeds 30 μm, the surface roughness of the coating layer becomes too large, which makes it difficult to sufficiently charge the toner and reduces the mechanical strength of the coating layer. Therefore, it is not preferable.

The true density of the spherical particles used in the present invention is 3
It is preferably g / cm ³ or less and 2.7 g / cm ³
It is more preferable that the amount is 0.9 to 2.3 g / c.
It is more preferably m ³ . That is, when the true density of the spherical particles exceeds ³ g / cm ³ , the dispersibility of the spherical particles in the resin coating layer becomes insufficient, and it becomes difficult to impart uniform roughness to the surface of the resin coating layer. However, it is not preferable because the toner is uniformly charged and the strength of the coating layer becomes insufficient.

The true density of the spherical particles is 0.9 g / cm.
When it is less than ^3, the dispersibility of the spherical particles in the coating layer becomes insufficient, which is not preferable.

The spherical shape in the spherical particles used in the present invention means that the ratio of the major axis / minor axis of the particles in the projected image of the particle is 1.
It means a substance of about 0 to 1.5, and in the present invention, it is preferable to use particles having a ratio of major axis / minor axis of 1.0 to 1.2.

When the ratio of the major axis / minor axis of the spherical particles exceeds 1.5, the dispersibility of the spherical particles in the resin coating layer decreases and the surface roughness of the resin coating layer becomes uneven. It is not preferable in terms of uniform charging of the toner and strength of the resin coating layer.

As such spherical particles used in the present invention, known particles can be used and are not particularly limited. For example, spherical resin particles, spherical metal oxide particles, spherical carbonized particles, etc. Can be mentioned.

As the spherical resin particles, those obtained by, for example, suspension polymerization or dispersion polymerization can be used. Spherical resin particles can impart a suitable surface roughness to the resin coating layer with a smaller amount of addition, and since the surface shape of the resin coating layer can be easily made uniform, it is preferably used among the spherical particles. be able to. Examples of materials for such spherical resin particles include acrylic resin particles such as polyacrylate and polymethacrylate, polyamide resin particles such as nylon, polyolefin resin particles such as polyethylene and polypropylene, silicone resin particles, and phenol resin. Examples include particles, polyurethane resin particles, styrene resin particles, benzoguanamine particles, and the like. The resin particles obtained by the pulverization method may be thermally or physically spheroidized before use.

In addition, an inorganic substance is attached to the surface of the spherical particles.
It may be used or fixed. With such inorganic substances
Then SiO₂, SrTiO₃, CeO₂, CrO, A
i₂O ₃, Oxides such as ZnO and MgO, Si₃N_FourNitriding of etc.
Thing; carbide such as SiC; CaSO_Four, BaSO_Four, CaC
O₃And the like. like this
Inorganic substances may be treated with a coupling agent before use.
Yes.

The inorganic material treated with the coupling agent can be preferably used for the purpose of improving the adhesion between the spherical particles and the coating resin, or for imparting hydrophobicity to the spherical particles. Examples of such coupling agents include silane coupling agents, titanium coupling agents, zircoaluminate coupling agents, and the like. More specifically, for example, as a silane coupling agent, hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, Benzyldimethylchlorosilane, brommethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethyl Diethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinylteto Lamethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and dimethyl having 2 to 12 siloxane units per molecule and having a hydroxyl group bonded to a silicon atom directed to each terminal unit. Examples include polysiloxane and the like.

By treating the surface of the spherical resin particles by adhering or fixing the inorganic substance thereto, dispersibility in the resin coating layer, uniformity of the coating layer surface, stain resistance of the coating layer,
The charge imparting property to the toner, the abrasion resistance of the coating layer, and the like can be improved.

The spherical particles used in the present invention are preferably electrically conductive. That is, by imparting conductivity to the spherical particles, it is possible to prevent charges from accumulating on the surface of the particles and to reduce toner adhesion and improve toner chargeability.

In the present invention, as the conductivity of the spherical particles, particles having a volume resistance value of 10 ⁶ Ω · cm or less, more preferably 10 ⁻³ to 10 ⁶ Ω · cm are preferable.
When the volume resistance of the spherical particles exceeds 10 ⁶ Ω · cm, the contamination and fusion of the toner are likely to occur around the spherical particles exposed on the surface of the resin coating layer due to abrasion, and quick and uniform charging is performed. It is difficult to do so, which is not preferable.

A charge control agent may be further added to the resin coating layer used in the present invention in order to control the charge imparting ability to the toner. As the charge control agent, for example,
Modified products of nigrosine and fatty acid metal salts, quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and onium such as phosphonium salts which are analogs thereof. Salts and lake pigments thereof (as a laker, phosphotungstic acid, phosphomolybdic acid, phosphotungstic molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.) higher fatty acid metal salts Butyltin oxide, dioctyltin oxide, dicyclohexyltin oxide and other diorganotin oxides; thibutyltin borate, dioctyltin borate,
Diorgano tin borates such as dicyclohexyl tin borate; guanidines, imidazole compounds, fluorine resins, polyamide resins, nitrogen-containing acrylic resins and the like.

Next, the structure of the developer carrying member of the present invention will be described. The developer carrying member of the present invention has a substrate and a resin coating layer formed on the surface of the substrate.

The shape of the substrate includes a cylindrical member, a columnar member, a belt-shaped member and the like. When a non-contact developing method is used for the photosensitive drum, a metal cylindrical member is preferably used, and specifically, a metal cylindrical tube is preferably used. As the metal cylindrical tube, nonmagnetic ones such as stainless steel, aluminum and alloys thereof are preferably used.

In the case of using the developing method of directly contacting with the photosensitive drum, a circular member having a layered structure containing a metal cored bar and a rubber or elastomer such as urethane, EPDM or silicon is preferably used as the substrate. To be Further, in the developing method using a magnetic developer, a magnet roller or the like having a magnet therein is arranged inside the developer carrier in order to magnetically attract and hold the developer on the developer carrier. In that case, the base body may be cylindrical and a magnet roller may be disposed inside the base body.

The constitution of the resin coating layer in the developer carrying member of the present invention will be described below. 1 to 4 are schematic sectional views showing a part of the developer carrying member of the present invention. Figure 1
4 to 4, a resin coating layer 17 in which graphitized particles a having a specific degree of graphitization and hardness are dispersed in a coating resin b.
Are laminated on a base 16 made of a metal cylindrical tube.

FIG. 1 shows that the graphitized particles a are dispersed in the coating resin b. The graphitized particles a contribute to formation of relatively small irregularities on the surface of the resin coating layer 17, conductivity imparting property, releasability to toner, and charge imparting property to toner.

In FIG. 2, the graphitized particles a are the resin coating layer 17
3 shows a configuration in which relatively large irregularities are formed on the surface of and the conductive fine particles c are added to the coating resin b in addition to the graphitized particles a to increase the conductivity. The conductive fine particles c themselves do not contribute much to the formation of substantial unevenness. However, it is not limited to the conductive fine particles c, and also includes a mode in which minute unevenness is formed by another solid particle added.

FIG. 3 shows a model diagram in which spherical particles d are further added to the coating resin b in order to give relatively large irregularities to the surface of the resin coating layer 17, where the graphitized particles a are coated with the resin. Small irregularities are formed on the surface of the layer 17. Such a configuration is advantageous when used in a developing device of a type in which the developer regulating member is elastically pressed against the developer carrying member (via the toner). That is, the spherical particles d on the surface of the resin coating layer 7 regulate the pressure contact force of the elastic regulating member, and the graphitized particles a form small irregularities so that the toner and the resin of the resin coating layer and the graphitized particles a are formed. It also plays a role of adjusting the contact charging opportunity and the releasability of the toner from the surface of the resin coating layer.

In FIG. 4, both the graphitized particles a and the spherical particles d contribute to the formation of irregularities on the surface of the resin coating layer 17. Such a form may be implemented, for example, when the spherical particles d are intended to have other functions such as conductivity, charge imparting property, and abrasion resistance in addition to imparting unevenness.

As described above, in the present invention, the particle diameters of the graphitized particles, the conductive particles and the spherical particles are adjusted according to the additional function required for the developer carrier and the difference in the developing system. It is possible to form the resin coating layer of each aspect as described above.

Next, the composition ratio of each component constituting the resin coating layer will be described. This composition ratio is a particularly preferable range in the present invention, but the present invention is not limited to this.

The content of the graphitized particles dispersed in the resin coating layer is preferably 2 to 150 parts by weight, more preferably 4 to 100 parts by weight, based on 100 parts by weight of the coating resin. The effect of maintaining the surface shape of the carrier and imparting the charge to the toner is further exhibited. When the content of the graphitized particles is less than 2 parts by mass, the effect of adding the graphitized particles is small, and when it exceeds 150 parts by mass, the adhesion of the resin coating layer becomes too low and the abrasion resistance deteriorates. It may happen.

When the content of the conductive fine particles which can be contained in the resin coating layer together with the above graphitized particles is preferably 40 parts by mass or less, more preferably 2 to 35 parts by mass with respect to 100 parts by mass of the coating resin. In addition, the volume resistance can be adjusted to the desired value as described above without impairing other physical properties required for the resin coating layer, which is preferable.

When the content of the conductive fine particles exceeds 40 parts by mass, the strength of the resin coating layer is lowered, which is not preferable.

When spherical particles are contained in the resin coating layer in combination with the above graphitized particles, the content of the spherical particles is
The range of 2 to 120 parts by mass, and more preferably 2 to 80 parts by mass with respect to 100 parts by mass of the coating resin is used to maintain the surface roughness of the resin coating layer and prevent toner contamination and toner scattering. In, particularly preferable results are given. When the content of the spherical particles is less than 2 parts by mass, the effect of adding the spherical particles is small, and when it exceeds 120 parts by mass, the chargeability of the toner may be too low.

In the present invention, in order to adjust the charging property of the developer carrying member, a charge control agent may be contained in the resin coating layer in combination with the graphitized particles. In that case, the content of the charge control agent is preferably 1 to 100 parts by mass with respect to 100 parts by mass of the coating resin. If it is less than 1 part by mass, the effect of charge controllability due to addition is not seen, and 10
When it exceeds 0 parts by mass, poor dispersion is likely to occur in the resin coating layer and the strength of the coating film tends to be lowered.

In the present invention, the arithmetic mean roughness (hereinafter referred to as "Ra") is 0.3 as the roughness of the surface of the resin coating layer.
To 3.5 μm, preferably 0.5 to 3.0 μm
More preferably m. When Ra on the surface of the resin coating layer is less than 0.3 μm, it becomes difficult to form irregularities on the surface of the resin coating layer for sufficiently carrying the developer, and the amount of the developer on the developer carrier is unstable. At the same time, the abrasion resistance and the toner stain resistance of the resin coating layer may become insufficient.

When Ra exceeds 3.5 μm, the amount of the developer carried on the developer carrying member becomes too large, and it becomes difficult to uniformly charge the developer, and the mechanical strength of the resin coating layer decreases. I may end up doing it.

The layer thickness of the resin coating layer having the above structure is preferably 25 μm or less, more preferably 20 μm.
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 resin coating layer, but is 4000 to 2000 as the attached mass.
It can be obtained by setting it to about 0 mg / m ² .

Next, the developing device of the present invention having the developer carrying member of the present invention as described above, the image forming apparatus having the developing device, and the process cartridge of the present invention will be described. FIG. 5 is a schematic view showing an embodiment of a developing device having a developer carrying member of the present invention when a magnetic one-component developer is used as the developer. In FIG. 5, an electrophotographic photosensitive drum (electrophotographic photosensitive member) 1 as an electrostatic latent image carrier that holds an electrostatic latent image formed by a known process.
Is rotated in the direction of arrow B.

The developing sleeve 8 as the developer carrying member is
It is arranged so as to face the electrophotographic photosensitive drum 1 with a predetermined gap. The developing sleeve 8 carries the one-component developer 4 having a magnetic toner supplied by a hopper 3 as a developer container and rotates in the direction of arrow A to face the developing sleeve 8 on the surface of the photosensitive drum 1. Then, the developer 4 is conveyed to the developing area D which is the closest portion. As shown in FIG. 5, in the developing sleeve 8, a magnet roller 5 containing a magnet is arranged in order to magnetically attract and hold the developer 4 on the developing sleeve 8.

The developing sleeve 8 used in the developing device of the present invention has a conductive coating layer 7 as a resin coating layer coated on the metal cylindrical tube 6 as a substrate. A stirring blade 10 for stirring the developer 4 is provided in the hopper 3. Reference numeral 12 is a gap indicating that the developing sleeve 8 and the magnet roller 5 are not in contact with each other.

The developer 4 obtains a triboelectric charge capable of developing the electrostatic latent image on the photosensitive drum 1 by friction between the magnetic toners and the conductive coating layer 7 on the developing sleeve 8. In FIG. 5, the developer 4 conveyed to the developing area D
In order to form this layer and regulate this layer thickness, the magnetic regulation blade 2 made of a ferromagnetic metal as a developer layer thickness regulation member has a gap width of about 50 to 500 μm from the surface of the development sleeve 8. Is hung from the hopper 3 so as to face the. A magnetic layer from the magnetic pole N1 of the magnet roller 5 concentrates on the magnetic regulation blade 2 to form a thin layer of the developer 4 on the developing sleeve 8. In addition,
In the present invention, a non-magnetic blade may be used instead of the magnetic regulation blade 2. The thickness of the thin layer of the developer 4 thus formed on the developing sleeve 8 is
It is preferably thinner than the minimum gap between the developing sleeve 8 and the photosensitive drum 1 in the developing area D.

The developer carrying member of the present invention is particularly effective when incorporated in a developing device of the type which develops an electrostatic latent image by a thin layer of the developer as described above, that is, a non-contact type developing device. In the developing area D, the developer carrier of the present invention is also applied to a developing device in which the thickness of the developer layer is not less than the minimum gap between the developing sleeve 8 and the photosensitive drum 1, that is, a contact type developing device. can do. In the following description, in order to avoid complication of the description, the non-contact type developing device as described above is taken as an example.

In order to fly the one-component developer 4 having magnetic toner carried on the developing sleeve 8, a developing bias voltage is applied to the developing sleeve 8 by a developing bias power source 9 as a bias means. When a direct current voltage is used as the developing bias voltage, a voltage having an intermediate value between the potential of the image portion (the area where the developer 4 is adhered and visualized) of the electrostatic latent image and the potential of the background portion is applied to the developing sleeve 8. It is preferable to apply. In order to increase the density of the developed image or improve the gradation, an alternating bias voltage may be applied to the developing sleeve 8 to form an oscillating electric field in the developing area D, the direction of which is alternately inverted. . In this case, it is preferable to apply to the developing sleeve 8 an alternating bias voltage in which a DC voltage component having an intermediate value between the potential of the developed image portion and the potential of the background portion is superimposed.

In the case of so-called normal development, in which toner is visualized by adhering toner to a high potential portion of an electrostatic latent image having a high potential portion and a low potential portion, the polarity is opposite to that of the electrostatic latent image. Toner is used. In the case of so-called reversal development, in which toner is attached to the low potential part of the electrostatic latent image having the high potential part and the low potential part to visualize it, the toner charged to the same polarity as the polarity of the electrostatic latent image is used. To do. High potential and low potential are expressions using absolute values. In either case, the developer 4
Is charged at least by friction with the developing sleeve 8.

FIGS. 6 and 7 are schematic structural views showing another embodiment of the developing device of the invention.

In the developing device shown in FIGS. 6 and 7, a material having rubber elasticity such as urethane rubber or silicone rubber is used as a developer layer thickness regulating member for regulating the layer thickness of the developer 4 on the developing sleeve 8. Alternatively, an elastic regulating blade (elastic regulating member) 11 made of an elastic plate made of a material having metallic elasticity such as phosphor bronze or stainless steel is used. In the developing device shown in FIG. 6, the elasticity regulating blade 11 is pressed against the developing sleeve 8 in the direction of rotation and in the forward direction. In the developing device shown in FIG.
The feature is that they are pressed against each other in the direction opposite to the rotating direction. In these developing devices, the developer layer thickness regulating member is elastically pressed against the developing sleeve 8 via the developer layer. As a result, a thin layer of the developer is formed on the developing sleeve, so that a thinner developer layer can be formed on the developing sleeve 8 as compared with the case of using the magnetic regulation blade described in FIG.

In the developing device shown in FIGS. 6 and 7,
Other basic structure is the same as that of the developing device shown in FIG.
Those having the same reference numeral basically indicate the same member.

FIGS. 5 to 7 are merely schematic illustrations of the developing device of the present invention, and various forms such as the shape of the developer container (hopper 3), the presence or absence of the stirring blades 10, the arrangement of the magnetic poles, etc. Needless to say. Of course, these devices can also be used for development using a two-component developer containing toner and carrier.

FIG. 8 is a schematic view showing an example of the construction of the developing device of the present invention when a non-magnetic one-component developer is used.
In FIG. 8, an electrophotographic photosensitive drum 1 as an image carrier that carries an electrostatic latent image formed by a known process.
Is rotated in the direction of arrow B. The developing sleeve 8 as a developer carrying member is composed of a metal cylindrical tube (base) 6 and a resin coating layer 7 formed on the surface thereof. Since a non-magnetic one-component developer is used, no magnet is provided inside the metal cylindrical tube 6. A cylindrical member may be used instead of the metal cylindrical tube.

The hopper 3, which is a developer container, is provided with a stirring blade 10 for stirring the non-magnetic one-component developer 4 '.

The developer 4'is supplied to the developing sleeve 8 and is present on the surface of the developing sleeve 8 after development.
The developer supplying / peeling member 13 for peeling off the toner is in contact with the developing sleeve 8. The supply / stripping roller 13 which is a developer supply / stripping member rotates in the same direction as the developing sleeve 8 to supply / strip the roller 1.
The surface of 3 moves in the counter direction with the surface of the developing sleeve 8. As a result, the one-component non-magnetic developer having the non-magnetic toner supplied from the hopper 3 is supplied to the developer sleeve 8. When the developing sleeve 8 carries the one-component developer 4'and rotates in the direction of arrow A, the non-magnetic one-component developer 4'is formed in the developing region D, which is a region facing the developing sleeve 8 on the surface of the photosensitive drum 1. Be transported. The developer layer thickness of the one-component developer carried on the developing sleeve 8 is regulated by the developer layer thickness regulating member 11 that is in pressure contact with the surface of the developing sleeve 8 via the developer layer. By friction with the developing sleeve 8, the non-magnetic one-component developer 4'obtains a triboelectric charge capable of developing the electrostatic latent image on the photosensitive drum 1.

The thin layer of the non-magnetic one-component developer 4'formed on the developing sleeve 8 is thinner than the minimum gap in the developing area D between the developing sleeve 8 and the photosensitive drum 1 in the developing section. It is preferably one. The present invention is particularly effective for a non-contact type developing device that develops an electrostatic latent image with such a developer layer. However, the present invention can also be applied to a contact type developing device in which the thickness of the developer layer in the developing section is equal to or larger than the minimum gap between the developing sleeve 8 and the photosensitive drum 1. In order to avoid complication of the description, a non-contact type developing device will be taken as an example in the following description.

A developing bias voltage is applied from the developing bias power source 9 to the developing sleeve 8 in order to fly the one-component non-magnetic developer 4'having the non-magnetic toner carried thereon. When a direct current voltage is used as the developing bias voltage, the voltage between the potential of the image portion of the electrostatic latent image (the area where the non-magnetic developer 4'is visualized) and the potential of the background portion is , Is preferably applied to the developing sleeve 8. In order to increase the density of the developed image or improve the gradation, an alternating bias voltage may be applied to the developing sleeve 8 to form an oscillating electric field whose direction is alternately inverted in the developing portion. In this case, it is preferable to apply to the developing sleeve 8 an alternating bias voltage in which a DC voltage component having a value between the potential of the image portion and the potential of the background portion is superimposed.

In so-called normal development in which a developer is attached to a high potential portion of an electrostatic latent image having a high potential portion and a low potential portion to visualize it, the developer charged to a polarity opposite to that of the electrostatic latent image is charged. use. Further, in so-called reversal development in which toner is visualized by attaching toner to a low potential portion of the electrostatic latent image, the developer is a developer that is charged to the same polarity as the polarity of the electrostatic latent image. Note that the high potential and the low potential are expressions using absolute values. In any case, the non-magnetic one-component developer 4'is charged with the polarity for developing the electrostatic latent image by friction with the developing sleeve 8.

As the developer supplying / peeling member 13,
An elastic roller member such as resin, rubber or sponge is preferable.
As the stripping member, a belt member or a brush member can be used instead of the elastic roller. A developer supplying / peeling member 2 for the developer not transferred to the photoreceptor 1 for development.
Thus, once peeled off from the sleeve surface, generation of immobile developer on the sleeve is prevented, and the charge of the developer is made uniform.

When the supplying / peeling roller 13 made of an elastic roller is used as the developer supplying / peeling member, the peripheral speed of the supplying / peeling roller 13 is the same.
When the surface rotates in the counter direction with respect to the developing sleeve 8, the peripheral speed of the developing sleeve 8 is 100%, preferably 20 to 120%, and more preferably 30 to 100%.
Is.

The peripheral speed of the feeding / peeling roller 13 is 20%.
If it is less than 1, the supply of the developer is insufficient, the followability of a solid image is deteriorated, which causes a ghost image, and the peripheral speed is 12
If it exceeds 0%, the developer supply amount becomes large, which causes fog due to poor regulation of the developer layer thickness and insufficient charge amount, and further tends to damage the toner, and therefore fog due to toner deterioration and toner fusion It is easy to cause

When the rotation direction of the surface of the supply / peeling roller 13 is the same (forward) direction as the rotation direction of the surface of the developing sleeve, the peripheral speed of the supply roller is preferably 100 to 100 with respect to the sleeve peripheral speed. 300%, more preferably 10
1 to 200% is preferable in terms of the toner supply amount.

The rotation direction on the surface of the supply / peel roller 13 is preferably the counter direction and the rotation direction on the surface of the developing sleeve in terms of stripping property and supply property.

The amount of the developer supplying / peeling member 13 penetrating into the developing sleeve 8 is preferably 0.5 to 2.5 mm in terms of the developer supplying and peeling property.

When the amount of invasion of the developer supplying / peeling member 13 is less than 0.5 mm, ghost is likely to occur due to insufficient stripping, and when the amount of invasion exceeds 2.5 mm, toner damage is caused. Is large, and deterioration of the toner easily causes fusing and fogging.

In the developing device of FIG. 8, as a member for regulating the layer thickness of the non-magnetic one-component developer 4'on the developing sleeve 8,
An elastic regulation blade 11 made of a material having rubber elasticity such as urethane rubber or silicone rubber, or a material having metal elasticity such as phosphor bronze or stainless copper is used. By pressing the elastic regulating blade 11 against the developing sleeve 8 in a posture opposite to the rotating direction of the developing sleeve 8, a thinner developer layer can be formed on the developing sleeve 8.

As the elastic regulating blade 11, a polyamide elastomer (PAE) is provided on the surface of the phosphor bronze plate which can obtain a stable pressing force, in order to obtain a particularly stable regulating force and a stable (negative) charge imparting property to the toner. It is preferable to use one having a pasted structure. Examples of the polyamide elastomer (PAE) include a copolymer of polyamide and polyether.

The contact pressure of the developer layer thickness regulating member 11 against the developing sleeve 8 is a linear pressure of 5 to 50 g / cm, which stabilizes the regulation of the developer and suitably adjusts the developer layer thickness. It is preferable because it can be obtained.

When the contact pressure of the developer layer thickness regulating member 11 is less than 5 g / cm of linear pressure, the regulation of the developer becomes weak,
If the linear pressure exceeds 50 g / cm, the toner may be damaged, and the toner may be greatly damaged, and the toner may be deteriorated or fused to the sleeve and the blade.

The developer carrying member of the present invention is particularly effective when applied to a device in which the developer supplying / peeling member 13 and the developer layer thickness regulating member 11 are in pressure contact with such a developing sleeve 8. Is.

That is, with respect to the developing sleeve 8, the developer supplying / peeling member 13 and the developer layer thickness regulating member 11 are provided.
, The surface of the developing sleeve 8 is in a use environment in which abrasion and fusion of the developer are more likely to occur due to the members to be pressed against each other. Therefore, the resin coating of the present invention having excellent durability The effect of the developer carrier having a layer is effectively exhibited.

Next, an example of an image forming apparatus using the developing device of the present invention illustrated in FIG. 7 will be described with reference to FIG. First, the surface of the photosensitive drum 101 as the electrostatic latent image carrier is negatively charged by the contact (roller) charging means 119 as the primary charging means, and the image is scanned by the exposure 115 of the laser beam as the latent image forming means. The digital latent image (electrostatic latent image) is the photosensitive drum 10.
1 is formed on. Next, by using a developing device (developing means) having an elastic regulating blade 111 as a developer layer thickness regulating member and a developing sleeve 108 as a developer carrying body containing a multipolar permanent magnet 105, The digital latent image is reversely developed by the one-component developer 104 having magnetic toner in the hopper 103. As shown in FIG. 9, in the developing area D, the conductive substrate of the photosensitive drum 101 is grounded, and the developing sleeve 108 is applied with alternate bias, pulse bias and / or DC bias by the bias applying means 109. Next, when the recording material P is conveyed and reaches the transfer portion, the contact (roller) transfer means 113 as a transfer means charges the recording material P from the back surface (the surface opposite to the photosensitive drum side) by the voltage applying means 114. As a result, the developed image (toner image) formed on the surface of the photosensitive drum 101 is transferred to the contact transfer unit 11.
3 is transferred onto the recording material P. Next, the photosensitive drum 10
The recording material P separated from No. 1 is conveyed to a heating and pressure roller fixing device 117 as fixing means, and the fixing device 117 performs a fixing process of the toner image on the recording material P.

The one-component developer 104 remaining on the photosensitive drum 101 after the transfer step is the cleaning blade 118.
It is removed by the cleaning means 118 having a. When the amount of the remaining one-component developer 104 is small, the cleaning process can be omitted. The photosensitive drum 101 after cleaning may be erased 11 if necessary.
The charge is removed by 6, and the above steps starting from the charging step by the contact (roller) charging means 119 as the primary charging means are repeated.

In the series of steps described above, the photosensitive drum (that is, the electrostatic latent image carrier) 101 has a photosensitive layer and a conductive substrate, and rotates in the direction of the arrow. The non-magnetic cylindrical developing sleeve 108, which is a developer carrying member, rotates in the developing area D so as to proceed in the same direction as the surface of the photosensitive drum 101. Inside the developing sleeve 108, a multi-pole permanent magnet (magnet roll) 105 which is a magnetic field generating means.
Are arranged so that they do not rotate. The one-component developer 104 in the developer container 103 is applied and carried on the developing sleeve 108, and by friction with the surface of the developing sleeve 108 and / or friction between magnetic toners, for example,
A negative tribo charge is given. Further, an elastic regulation blade 111 is provided so as to elastically press the developing sleeve 108, and the thickness of the developer layer is thin (30 to 300 μm).
In addition, the photosensitive drum 1 in the developing area D is regulated uniformly.
A developer layer thinner than the gap between 01 and the developing sleeve 108 is formed. By adjusting the rotation speed of the developing sleeve 108, the surface speed of the developing sleeve 108 becomes substantially equal to or close to the surface speed of the photosensitive drum 101. In the developing area D, an AC bias or a pulse bias may be applied to the developing sleeve 108 as a developing bias voltage by the bias applying unit 109. This AC bias has an f of 200 to 4,0.
00 Hz and Vpp may be 500 to 3,000 V.

Developer in development area D (magnetic toner)
At the time of transfer, the magnetic toner transfers to the electrostatic latent image side due to the electrostatic force on the surface of the photosensitive drum 101 and the action of the developing bias voltage such as an AC bias or a pulse bias.

Instead of the elastic regulation blade 111, a magnetic doctor blade made of iron or the like can be used. Although the charging roller 119 as the contact charging means is used as the primary charging means in the above description, it may be a contact charging means such as a charging blade or a charging brush, or a non-contact corona charging means. However, the contact charging means is preferable in that ozone is less generated by charging. Further, as the transfer means, the contact transfer means such as the transfer roller 113 as described above is used, but a non-contact corona transfer means may be used. However, also in this case, the contact transfer means is more preferable because ozone is less generated by transfer.

FIG. 10 shows a specific example of the process cartridge of the present invention. In the following description of the process cartridge, components having the same functions as the constituent members of the image forming apparatus described with reference to FIG. 9 will be described using the same reference numerals as those in FIG. 9. The process cartridge of the present invention is one in which at least the developing means and the electrostatic latent image carrier are integrally formed into a cartridge, and can be attached to and detached from the image forming apparatus main body (for example, a copying machine, a laser beam printer, a facsimile machine). Is configured.

In the embodiment shown in FIG. 10, the developing means 1
20, drum-shaped electrostatic latent image carrier (photosensitive drum) 10
1. A process cartridge 150 in which a cleaning unit 118 having a cleaning blade 118a and a contact (roller) charging unit 119 as a primary charging unit are integrated.
Is exemplified. In the present embodiment, the developing means 120 is housed in the developing sleeve 108, the elasticity regulating blade 111, the developer container 103, and the developer container 103.
And a one-component developer 104 having a magnetic toner.
The developing process in the developing means 120 is performed by the developer 104.
During development, a predetermined electric field is formed between the photosensitive drum 101 and the development sleeve 108 by the development bias voltage from the bias applying means, and development is performed. The distance between the photosensitive drum 101 and the developing sleeve 108 is very important for carrying out this developing process properly.

In FIG. 10, an embodiment in which the four components of the developing means 120, the electrostatic latent image carrier 101, the cleaning means 118, and the primary charging means 119 are integrated into a cartridge has been described. The developing means and the electrostatic latent image carrier may be at least two components integrally formed into a cartridge, and the developing means, the electrostatic latent image carrier and the cleaning means may be used. Or a developing means, an electrostatic latent image carrier, and a primary charging means. Alternatively, the developing means, the electrostatic latent image carrier, and the primary charging means may be included. Alternatively, other components may be added to integrally form a cartridge. It is possible.

Next, the developer used in the developing device of the present invention will be described. The developer used in the present invention may be a one-component developer containing toner as a main component (without carrier) or a two-component developer containing toner and carrier. When the developer used in the present invention is a one-component developer, even if the toner is a magnetic one-component developer which is a magnetic toner, it is a non-magnetic one-component developer which is a non-magnetic toner. It may be.

The toner is a fine powder in which a binder resin, a release agent, a charge control agent, a colorant and the like are melt-kneaded, solidified and then pulverized, and then classified and the like to make the particle size distribution uniform.
As the binder resin used in the toner, generally known resins can be used.

For example, styrene, α-methylstyrene,
Homopolymers of styrene such as p-chlorostyrene and its substitution products; styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene-ethyl acrylate copolymers, styrene-butyl acrylate copolymers, styrene. -Octyl acrylate copolymer, styrene-dimethylaminoethyl copolymer, styrene-methylmethacrylate copolymer, styrene-ethylmethacrylate copolymer, styrene-butylmethacrylate copolymer, styrene-dimethylaminomethacrylate Ethyl copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester Styrenic copolymers such as copolymers; Methyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, temper resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, paraffin Wax, carnauba wax and the like can be used alone or in combination.

Further, the toner may contain a pigment as a colorant. For example, carbon black, nigrosine dye, lamp black, Sudan Black SM, First Yellow G, Benzidine Yellow, Pigment Yellow, India First Orange, Irgadine Red, Paranitroaniline Red, Toluidine Red, Carmine FB, Permanent Bordeaux FRR, Pigment Orange R, Resor Red 2G, Lake Red C, Rhodamine FB, Rhodamine B Lake, Methyl Bio Red B Lake, Phthalocyanine Blue, Pigment Blue, Brilliant Green B,
Phthalocyanine Green, Oil Yellow GG, Pomelo First Yellow CGG, Kayaset Y963, Kayaset YG, Pomelo Fast Orange RR, Oil Scarlet, Orazol Brown B, Pomelo
First scarlet CG, oil pink OP, etc. can be applied.

In order to use the toner as a magnetic toner,
Magnetic powder may be contained in the toner. As such magnetic powder, a substance that is magnetized in a magnetic field is used, and examples thereof include powders of ferromagnetic metals such as iron, cobalt and nickel, and alloys and compounds such as magnetite, hematite and ferrite. The content of the magnetic powder is preferably 15 to 70 mass% with respect to the toner mass.

For the purpose of improving releasability and fixing property at the time of fixing the toner, wax may be contained in the toner. Examples of such waxes include paraffin wax and its derivatives, microcrystalline wax and its derivatives, Fischer-Tropsch wax and its derivatives, polyolefin wax and its derivatives, carnauba wax and its derivatives, and the like. And block copolymers with vinyl monomers,
Including graft modified products. Others, alcohol, fatty acids,
Acid amides, esters, ketones, hydrogenated castor oil and its derivatives, plant waxes, animal waxes, mineral waxes, petrolactam and the like can also be used.

If necessary, the toner may contain a charge control agent. The charge control agent includes a negative charge control agent and a positive charge control agent. The following substances control the toner to be negatively charged. For example, organic metal complexes and chelate compounds are effective, and there are monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid metal complexes. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

Further, there are the following substances for positively charging the toner. Modified products of nigrosine and fatty acid metal salts, quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and onium such as phosphonium salts which are analogs thereof. Salts and lake pigments thereof (as a laking agent, phosphotungstic acid, phosphomolybdic acid, phosphotungstic molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.), metal salts of higher fatty acids Dibutyltin oxide,
Diorganotin oxides such as dioctyltin oxide and dicyclohexyltin oxide; Diorganotin borates such as dibutyltin borate, dioctyltin borate and dicyclohexyltin borate; guanidine compounds and imidazole compounds.

If necessary, the toner is used by externally adding fine powder such as inorganic fine powder for the purpose of improving fluidity. Such fine powders include silica fine powder, metal oxides such as alumina, titania, germanium oxide, and zirconium oxide; carbides such as silicon carbide and titanium carbide; and inorganic fine powders such as nitrides such as silicon nitride and germanium nitride. The body is used.

These fine powders can be used after being organically treated with an organic silicon compound, a titanium coupling agent and the like. For example, as the organosilicon compound, hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromine. Methyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate,
Vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and 2 to 12 per molecule. 1 unit for each terminal unit with siloxane units
There is dimethyl polysiloxane containing a hydroxyl group bonded to Si for individual pieces.

It is also preferable to use untreated fine powder treated with a nitrogen-containing silane coupling agent, particularly in the case of positive toner. Examples of such treating agents include aminopropyltrimethoxysilane, aminopropyltriethoxysilane, dimethylaminopropyltrimethoxysilane, diethylaminopropyltrimethoxysilane, dipropylaminopropyltrimethoxysilane,
Dibutylaminopropyltrimethoxysilane, monobutylaminopropyltrimethoxysilane, dioctylaminopropyltrimethoxysilane, dibutylaminopropyldimethoxysilane, dibutylaminopropylmonomethoxysilane, dimethylaminophenyltrimethoxysilane, trimethoxysilyl-γ-propylphenyl Amine, trimethoxysilyl-γ-propylbenzylamine, trimethoxysilyl-γ-propylpiperidine, trimethoxysilyl-γ-propylmorpholine, trimethoxysilyl-γ-propylimidazole, and the like.

As the method for treating the fine powder with the silane coupling agent, for example, 1) a spray method and 2)
There are organic solvent method, 3) aqueous solution method and the like. Generally, the treatment by the spray method is a method in which the pigment is stirred, an aqueous solution of a coupling agent or a solvent solution is sprayed thereon, and then water or the solvent is removed and dried at about 120 to 130 ° C. In addition, the treatment by the organic solvent method means that the coupling agent is dissolved in an organic solvent (alcohol, benzene, halogenated hydrocarbon, etc.) containing a catalyst for hydrolysis together with a small amount of water, and the pigment is immersed in this, and then filtered. Alternatively, solid-liquid separation is performed by pressing and drying is performed at about 120 to 130 ° C. In the aqueous solution method, about 0.5% of the coupling agent is hydrolyzed in water or water-solvent having a constant pH,
After immersing the pigment here, solid-liquid separation is similarly performed and drying is performed.

As another organic treatment, it is also possible to use fine powder treated with silicone oil. The preferred silicone oil has a viscosity at 25 ° C. of about 0.5 to 10000 mm ² / sec, preferably 1 to 1
000 mm ² / sec is used, for example, methylhydrogen silicone oil, dimethyl silicone oil, phenylmethyl silicone oil, chlorophenylmethyl silicone oil, alkyl modified silicone oil, fatty acid modified silicone oil, polyoxyalkylene modified silicone oil, Examples thereof include fluorine-modified silicone oil.

It is also preferable to treat the fine powder with a silicone oil having a nitrogen atom in the side chain, particularly in the case of positive toner. The treatment with silicone oil can be performed, for example, as follows. The inorganic fine powder is violently agitated while heating if necessary,
It can be easily treated by spraying or vaporizing and spraying the above-mentioned silicone oil or a solution thereof, or making an inorganic fine powder into a slurry and dropping the silicone oil or a solution thereof while stirring. These silicone oils may be used alone or as a mixture of two or more, or may be used in combination or in multiple treatments. Further, the treatment with a silane coupling agent may be used together.

The toner used in the present invention as described above is preferably subjected to a spheroidizing treatment and a surface smoothing treatment by various methods, because the transferability is good and it is preferable. As such a method, an apparatus having a stirring blade or blade, etc., and a liner, casing, etc. is used, and for example, when passing the toner through a minute gap between the blade and the liner, the surface is smoothed by a mechanical force. A method of forming the toner or making the toner spherical may be used. There are also a method of spheroidizing the toner by suspending it in warm water, a method of exposing the toner to a hot air stream to spheroidize the toner, and the like.

As a method for producing spherical toner,
There is a method in which a mixture containing a monomer as a toner binder resin as a main component is suspended in water and polymerized to form a toner. As a general method, a polymerizable monomer, a colorant, a polymerization initiator, and if necessary, a crosslinking agent, a charge control agent, a release agent, and other additives are uniformly dissolved or dispersed to form a single amount. After a body composition, this monomer composition is a continuous layer containing a dispersion stabilizer, for example, dispersed in a water phase to a suitable particle size using a suitable stirrer, further polymerization reaction, This is a method of obtaining a developer having a desired particle size.

The developer used in the present invention can also be used as a two-component developer by mixing toner and carrier. Examples of the carrier material include magnetic metals such as iron, nickel and cobalt, and alloys thereof, or alloys containing rare earths, hematite, magnetite, manganese-zinc ferrite, nickel-zinc ferrite, manganese-magnesium alloy. Soft ferrite such as ferrite and lithium ferrite, copper
Examples thereof include iron-based oxides such as zinc-based ferrite, and mixtures thereof, and further, glass, ceramic particles such as silicon carbide, resin powder, resin powder containing a magnetic material, and the like, and usually have an average particle size of It is used as a granular material of about 20 to 300 μm.

As such a carrier, the above-mentioned granular materials may be directly used as carrier particles, but in order to adjust the triboelectric charge of the toner and prevent toner spent on the carrier, a silicone resin, Fluorine resin,
It is also possible to appropriately coat the surface of the particles with a resin using a coating agent such as acrylic resin or phenol resin.

The methods for measuring physical properties relating to the present invention will be described below. (1) Graphitization degree p (002) of graphitized particles The graphitization degree p (002) is obtained from the X-ray diffraction spectrum of graphite by a powerful automatic X-ray diffractometer "MXP18" system manufactured by Mac Science Co. The grid spacing d (00
2) was measured and d (002) = 3.440-0.086
It is calculated by (1-p (002) ² ).

For the lattice spacing d (002), CuKα was used as an X-ray source and CuKβ rays were removed by a nickel filter. High-purity silicon is used as the standard substance, and C
It is calculated from the peak positions of the (002) and Si (111) diffraction patterns. The main measurement conditions are as follows. X-ray generator: 18 kW Goniometer: Horizontal type goniometer Monochromator: Working tube voltage: 30.0 kV Tube current: 10.0 mA Measuring method: Continuous method Scan axis: 2θ / θ Sampling interval: 0.020 deg Scan speed: 6.000 deg / min Divergence slit: 0.50 deg Scattering slit: 0.50 deg Light receiving slit: 0.30 mm

(2) Indentation hardness value HUT of graphitized particles
[68] An indentation hardness value HUT [68] measured with a microhardness meter MZT-4 manufactured by Akashi Co., Ltd. using a triangular pyramid diamond indenter having a face angle with respect to the axis of 68 degrees, and is represented by the following formula ( It is represented by 2).

[0165]

[Equation 5] Indentation hardness value HUT [68] = K × F / (h2) ² (2) [where K: coefficient, F: test load, h2: maximum indentation depth of indenter] prepared for measurement As a sample to be used, the surface of the resin coating layer of the developer carrier is smoothed with a # 2000 polishing tape so that the graphitized particles in the resin coating are exposed.

Indentation hardness value HUT [6 of graphitized particles
8] is a graphitized particle having a size of 10 μm or more exposed on the surface of the coating resin layer after the sample is fixed and polished, and the indenter is aimed at the measurement to measure different graphitized particles of the same sample. Is measured at 10 or more points, and the average value is determined as the indentation hardness value HUT [68] of the graphitized particles.

The main measurement conditions are as follows. TE
The measurement is performed in ST MODE A. TEST MODE
A is for setting a load to be pushed into the sample for measurement, and there are two loads to be added: an initial load called a reference load F0 and a test load F1 which is a final load. During measurement, after the indenter contacts the sample, a reference load is applied to the sample, and the indenter is pushed into the sample by the load of the reference load. The point where the indenter is pushed in by the standard load is set as the zero point of the indentation depth, the test load is applied to the indenter, the set holding time and the test load are held, and the indenter depth h2 after holding the test load is The maximum indentation depth) is required. The indentation depth value HUT [68] is obtained from the following equation (3).

[Equation 6] Indentation hardness value HUT [68] = K × [(F1) ^0.5- (F0) ^0.5 ] ² / (h2) ² (3) [however, F1: test load (mN), F0: standard load] (M
N), h2: Indentation depth (μ of the indenter after holding the test load)
m), K: coefficient (K = 2.972, triangular pyramid indenter, 68 °)
SI unit system coefficient using)] Test load F1: 49.0 mN Reference load F0: 4.9 mN Pushing speed V: 1.00 μm / sec Holding time T2: 5 sec Unloading time T3: 5 sec Maximum of test load and indenter The indentation depth is preferably within a range not affected by the surface roughness of the coating layer surface and not affected by the base substrate, and in the present invention, the maximum indentation depth of the test load indenter is 1 to 2 μm. Measure the degree.

(3) Coefficient of friction μs The developer carrier is fixed in a horizontal position, and H is applied in the longitudinal direction.
EIDON Tribogear Muse (TYPE: 9
4i) brass (hard chrome treatment) slider is contacted. Further, the value of the friction coefficient μs is obtained by measuring 10 points by appropriately changing the measurement place on the surface of the developer carrying member and averaging the values.

(4) Average Circularity of Particle SF-1 A multi-image analyzer (manufactured by Beckman Coulter, Inc.) is used as a concrete measuring device capable of efficiently analyzing the circularity of many particles. Measure.

The multi-image analyzer is a combination of a particle size distribution measuring device using an electric resistance method, with a function of photographing a particle image by a CCD camera and a function of analyzing the photographed particle image. Specifically, the measurement particles uniformly dispersed in the electrolyte solution by ultrasonic waves, etc., is detected by the change in electric resistance when the particles pass through the aperture of Multisizer, which is a particle size distribution measuring device by the electric resistance method,
In synchronization with this, a strobe is emitted and a CCD camera captures a particle image. This particle image is taken into a personal computer, binarized and then image-analyzed.

Using the above-mentioned apparatus, the maximum length ML of the Pythagoras method of the projected particle image and the projected area A are obtained, and the projected area A is 30 μm or more of 2 μm or more.
The value of the circularity for 00 particles is calculated from the following formula (4), and the average circularity SF− is calculated by averaging the values.
Ask for 1.

[0172]

## EQU00007 ## Circularity = (4 × A) / {(ML) ² × π} (4)

(5) Measurement of toner particle size To 100 to 150 ml of an electrolyte solution, 0.1 to 5 ml of a surfactant (alkylbenzene sulfonate) is added, and to this, 2 to 20 mg of a measurement sample is added. The electrolytic solution in which the sample is suspended is dispersed by an ultrasonic disperser for 1 to 3 minutes, and 17 μm by the Coulter counter multisizer described above.
Alternatively, the particle size distribution or the like of 0.3 to 40 μm based on the volume is measured by using an aperture appropriately matched to the toner size such as 100 μm. The number average particle diameter and the weight average particle diameter measured under these conditions are calculated by computer processing, and the number average particle diameter of 1 is calculated from the number-based particle size distribution.
The cumulative ratio below the / 2 double diameter cumulative distribution is calculated, and the cumulative value below the 1/2 double diameter cumulative distribution is calculated. Similarly, the cumulative ratio of the double diameter cumulative distribution or more of the weight average particle diameter is calculated from the volume-based particle size distribution, and the cumulative value of the double diameter cumulative distribution or more is obtained.

(6) Measurement of Arithmetic Average Roughness (Ra) of Surface of Developer Carrier Based on the surface roughness of JIS B0601, a surf coder SE-3400 manufactured by Kosaka Laboratory was used as a measurement condition with a cutoff of 0. At 8 mm, an evaluation length of 4 mm, and a feed rate of 0.5 mm / s, measurements were made at 3 points in the axial direction × 2 points in the circumferential direction = 6 points, and the average value was taken.

(7) Measurement of volume resistance of resin coating layer A coating layer having a thickness of 7 to 20 μm is formed on a PET sheet having a thickness of 100 μm, and the standard is ASTM (D-991-8).
2) and Japan Rubber Association standard SRIS (2301-
1969), using a voltage drop type digital ohmmeter (manufactured by Kawaguchi Denki Seisakusho) provided with electrodes having a four-terminal structure for measuring the volume resistance of conductive rubber and plastic. The measurement environment is 20 to 25 ° C and 50 to 60 RH%.
And

(8) Particle size measurement of conductive particles having a particle size of 1 μm or more The particle size of conductive particles such as graphitized particles is the Coulter LS-130 particle size distribution meter (manufactured by Coulter Co.) Is measured. An aqueous module is used as the measuring method, and pure water is used as the measuring solvent.
Wash the inside of the measurement system of the particle size distribution meter with pure water for about 5 minutes, and add 10 to 25 mg of sodium sulfite as an antifoaming agent in the measurement system.
In addition, it executes a background function.

Next, 3 to 4 drops of the surfactant are added to 10 ml of pure water, and 5 to 25 mg of the measurement sample is further added. The aqueous solution in which the sample is suspended is dispersed by an ultrasonic disperser for about 1 to 3 minutes to obtain a sample solution. This sample solution is gradually added to the measuring system of the measuring device, and the PIDS on the screen of the device is 45 to 5
The sample concentration in the measurement system is adjusted so as to be 5% for measurement, and the number average particle diameter calculated from the number distribution is obtained.

(9) Particle size measurement of conductive particles having a particle size of less than 1 μm The particle size of the conductive particles is measured using an electron microscope. The photographing magnification is 60,000 times, but if difficult, the photograph is enlarged at a low magnification and then the photograph is enlarged to 60,000 times. The particle size of the primary particles is measured on the photograph. At this time, the major axis and the minor axis are measured, and the averaged value is taken as the particle size. This is measured for 100 samples, and the 50% value is taken as the average particle size.

(10) Measurement of resin coating layer film thickness (abrasion amount) KEYENC is used as a measurement of the coating layer abrasion amount (film abrasion).
A laser size measuring device manufactured by E company was used. Controller LS
Using -5500 and sensor head LS-5040T, the sensor part was separately fixed to the device equipped with the sleeve fixing jig and the sleeve feeding mechanism, and the measurement was performed from the average value of the outer diameter dimension of the sleeve. The measurement was carried out by dividing the lengthwise direction of the sleeve into 30 and measuring 30 points. Further, after rotating the sleeve 90 ° in the circumferential direction, 30 points were further measured, totaling 60 points, and the average value was taken. The outer diameter of the sleeve before applying the surface coating layer was measured in advance, the outer diameter after forming the surface coating layer, and the outer diameter after durable use were measured, and the difference between them was used as the coat film thickness and the scraped amount.

[0180]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples, but the examples do not limit the present invention. Incidentally, "%" and "part" in Examples and Comparative Examples
All are based on mass unless otherwise specified.

Example 1 As a raw material for graphitized particles,
The β-resin was extracted from the coal tar pitch by solvent fractionation, subjected to a heavy treatment by hydrogenation, and then the solvent-soluble component was removed with toluene to obtain bulk mesophase pitch. This bulk mesophase pitch was finely pulverized and subjected to oxidation treatment in air at about 300 ° C., then primary calcination at 1200 ° C. under a nitrogen atmosphere to carbonize, and then at 3,000 ° C. under a nitrogen atmosphere. It was graphitized by subsequent firing and further classified to obtain graphitized particles A-1 having a number average particle diameter of 6.5 μm. Table 1 shows the physical properties of the graphitized particles A-1.

[0182]

[Table 1]

Resol type phenolic resin solution (containing 50% methanol) 200 parts Graphitized particles (A-1) 60 parts Methanol 150 parts Glass beads having a diameter of 1 mm were added as media particles to the above material and dispersed by a sand mill. Then, the solid content of the dispersion liquid was diluted to 30% with methanol to obtain a coating liquid.

Using this coating solution, a resin coating layer was formed by a spray method on an aluminum cylindrical tube having an outer diameter of 16 mmφ and a center line average roughness Ra of 0.3 μm, which was ground, and then a hot air drying furnace was used. The resin coating layer was cured by heating at 150 ° C. for 30 minutes to prepare a developer carrying member B-1. Table 2 shows the formulation and physical properties of the resin coating layer of the obtained developer carrier B-1.

[0185]

[Table 2]

The developer carrying member B-1 was mounted on the image forming apparatus (equipped with contact roller charging means and contact roller transfer means) LBP1710 (manufactured by Canon Inc.) having the developing device shown in FIG. While supplying the system developer, 1.5
A durability evaluation test was carried out on 10,000 sheets of the developer carrying member. The following were used as the one-component developer. -Styrene-acrylic resin 100 parts-Magnetite 95 parts-Al complex of di-tert-butylsalicylic acid 2 parts-Low molecular weight polypropylene 4 parts The above materials were mixed by a Henschel mixer, and melt-kneaded and dispersed by a biaxial extruder. . After cooling the kneaded product, roughly crushed with a hammer mill, further finely crushed with a mechanical crusher, and then classified using an airflow classifier,
A fine powder (toner particles) having a number average particle diameter of 6.0 μm was obtained. 1.2 parts of hydrophobic colloidal silica treated with a silane coupling agent was externally added to 100 parts of this fine powder to obtain a magnetic toner, and this magnetic toner was used as a one-component developer. (Evaluation) A durability test was conducted on the following evaluation items,
The developer carrying members of Examples and Comparative Examples were evaluated.

Image evaluation of image density, fog, sleeve ghost, blotch, halftone uniformity, etc., toner charge amount (Q / M) and toner transport amount (M / M) on the developer carrier.
S), the abrasion resistance of the resin coating layer is 20 ° C / 60%
Normal temperature and humidity (N / N) environment, 24 ° C / 10% room temperature and low humidity (N / L) environment, 30 ° C / 80% high temperature and high humidity (H / H)
The durability was evaluated in each environment.

The results are shown in Tables 3 and 4. Good results were obtained for both the image and the durability. (1) Image Density Using a reflection densitometer RD918 (manufactured by Macbeth), the density of solid black portions when solid printing was performed was measured at 5 points, and the average value was used as the image density.

(2) Fog density The reflectance (D1) of the solid white portion of the recording paper on which an image has been formed is measured, and the reflectance (D2) of an unused recording paper of the same cut as the recording paper used for image formation. Was measured to obtain 5 values of D1-D2, and the average value thereof was used as the fog density. Reflectance is T
It measured with C-6DS (made by Tokyo Denshoku).

(3) Sleeve ghost The position of the developing sleeve where the image in which the solid white portion and the solid black portion are adjacent to each other is developed comes to the developing position when the developing sleeve is rotated next time, and the halftone image is developed. The density difference appearing on the halftone image was visually evaluated based on the following criteria. A: No difference in light and shade is seen. B: A slight shade difference is seen. C: Some difference in light and shade can be seen, but practical use is possible. D: The lightness difference which is a problem in practical use appears for one round of the sleeve. E: The density difference, which is a problem in practical use, appears for two sleeves or more.

(4) Blotch (defective image) Various kinds of images such as solid black, halftone and line image are formed,
With reference to visual observation of image defects such as wavy unevenness of the formed image, blotch (spotted unevenness), and toner coat defect on the developing sleeve when image formation is performed,
The evaluation result was evaluated based on the following criteria.

A: Neither the image nor the sleeve can be confirmed. B: Slightly visible on the sleeve, but hardly visible in the image. C: The first halftone image or the solid black image can be confirmed at the first round of the sleeve cycle. D: It can be confirmed with a halftone image or a solid black image, but can be used practically. E: An image defect, which is a practical problem, can be confirmed in the entire solid black image. F: An image defect, which is a practical problem, can be confirmed on a solid white image.

(5) Halftone Uniformity (White Streaks, White Bands) The formed image was visually observed for linear or band-shaped streaks running in the image forming direction, especially in halftone, and It was evaluated according to the standard. A: Neither the image nor the sleeve can be confirmed. B: If you look closely, you can see it slightly, but at first glance you can hardly see it. C: It can be confirmed slightly with halftone, but there is no problem with solid black. D: Streaks can be seen in halftone, but slight in solid black. E: The difference in shade can be confirmed even in a solid black image, but it is practical. F: There is a noticeable density difference that is a practical problem in the entire solid black image. G: An image with low density and very many streaks.

(6) Toner charge amount (Q / M) and toner transport amount (M / S) The toner carried on the developing sleeve is sucked and collected by the metal cylindrical tube and the cylindrical filter, and at that time, the metal cylindrical tube. From the amount of charge Q accumulated in the condenser through the amount of collected toner M, and the area S of toner suctioned, the amount of charge Q / M per unit mass (mC / kg) and the toner mass per unit area M / S (dg / m ² ) was calculated and used as the toner charge amount (Q / M) and the toner transport amount (M / S), respectively.

(7) Abrasion resistance of resin coating layer Arithmetic mean roughness (R
The amount of abrasion of the film thickness of a) and the resin coating layer was measured.

[0196]

[Table 3]

[0197]

[Table 4]

<Examples 2 to 3> Graphite particles A-1 used in Example 1 are the same as those in Graphite except that the secondary firing temperature was changed as shown in Table 1. Particles A-2 to A-3 were obtained. Obtained Graphitized Particles A-2 ~
Table 1 shows the physical properties of A-3. These graphitized particles A-2 ~
Developer carrying members B-2 to B-3 were prepared in the same manner as in Example 1 except that A-3 was used as the graphitized particles in the resin coating layer instead of A-1. The same evaluation as in 1 was performed. The formulation and physical properties of the resin coating layer of these developer carrying members are shown in Table 2, and the evaluation results are shown in Tables 3 and 4.

Example 4 In Example 1, the graphitized particles A-1 are the same as the graphitized particles A-1 except that the fine pulverization conditions of the bulk mesophase pitch of the raw material used and the classification conditions after the secondary firing are changed. Number average particle size 3.3 μm using the same method
Graphitized particles A-4 were obtained.

Table 1 shows the physical properties of the obtained graphitized particles A-4. A developer carrying member B-4 was prepared in the same manner as in Example 1 except that the graphitized particles A-4 were used instead of A-1 as the graphitized particles in the resin coating layer. The same evaluation as was done. The formulation and physical properties of the resin coating layer of this developer carrying member are shown in Table 2, and the evaluation results are shown in Tables 3 and 4.

Example 5 As a raw material for graphitized particles,
The coal-based heavy oil was heat-treated, and the generated crude mesocarbon microbeads were centrifuged, washed and purified with benzene, dried, and mechanically dispersed with an atomizer mill to obtain mesocarbon microbeads. The mesocarbon microbeads were subjected to primary firing at 1200 ° C. in a nitrogen atmosphere to carbonize them, and then secondary dispersion was performed with an atomizer mill, followed by secondary firing at 2800 ° C. in a nitrogen atmosphere to graphitize and further classify. And the number average particle size is 6.
7 μm graphitized particles A-5 were obtained. Table 1 shows the physical properties of the graphitized particles A-5.

Developer-carrying member B-5 in the same manner as in Example 1 except that graphitized particles A-5 were used instead of A-1 as the graphitized particles in the resin coating layer. Was prepared and evaluated in the same manner as in Example 1. The formulation and physical properties of the resin coating layer of this developer carrying member are shown in Table 2, and the evaluation results are shown in Tables 3 and 4.

<Examples 6 to 7> Graphitized particles A-6 were prepared in the same manner as in Example 5 except that the secondary firing temperature for obtaining graphitized particles A-5 was changed. ~ A
-7 was obtained. Table 1 shows the physical properties of the obtained graphitized particles A-6 to A-7.

A developer carrying member was prepared in the same manner as in Example 1 except that these graphitized particles A-6 to A-7 were used instead of A-1 as the graphitized particles in the resin coating layer. B-6
-B-7 were produced and evaluated in the same manner as in Example 1. Table 2 shows the formulation and physical properties of the resin coating layer of these developer carrying members.
Table 3 and Table 4 show the evaluation results.

<Comparative Example 1> As a raw material for the graphitized particles,
A mixture of coke and tar pitch is used, and the mixture is kneaded at a temperature equal to or higher than the softening point of the tar pitch, extruded, and primary-calcined at 1000 ° C. in a nitrogen atmosphere for carbonization, followed by impregnation with coal tar pitch. After that, it is secondarily fired at 2800 ° C. in a nitrogen atmosphere, graphitized, further pulverized and classified to have a number average particle diameter of 6.7 μm.
m graphitized particles a-1 were obtained. Table 1 shows the physical properties of the graphitized particles a-1.

A developer carrying member C-1 was prepared in the same manner as in Example 1 except that graphitized particles a-1 were used instead of A-1 as the graphitized particles in the resin coating layer. Was prepared and evaluated in the same manner as in Example 1. The formulation and physical properties of the resin coating layer of this developer carrying member are shown in Table 2, and the evaluation results are shown in Tables 3 and 4.

<Comparative Example 2> As a raw material for the graphitized particles,
Using spherical phenol resin particles, baking was performed at 2200 ° C. in a nitrogen atmosphere, and further classification was performed to obtain graphitized particles a-2 having a number average particle diameter of 6.4 μm. Graphitized particles a-
The physical properties of No. 2 are shown in Table 1.

A developer carrying member C-2 was used in the same manner as in Example 1 except that graphitized particles a-2 were used instead of A-1 as the graphitized particles in the resin coating layer. Was prepared and evaluated in the same manner as in Example 1. The formulation and physical properties of the resin coating layer of this developer carrying member are shown in Table 2, and the evaluation results are shown in Tables 3 and 4.

Comparative Example 3 Graphitized particles A-1 used in Example 1 are the same as those shown in Table 1, except that the secondary firing temperature was changed. a-
Got 3. Table 1 shows the physical properties of the obtained graphitized particles a-3. A developer carrying member C-3 was prepared in the same manner as in Example 1 except that the graphitized particles a-3 were used as the graphitized particles in the resin coating layer instead of A-1. The same evaluation as in 1 was performed. The formulation and physical properties of the resin coating layer of this developer carrying member are shown in Table 2, and the evaluation results are shown in Tables 3 and 4.

<Comparative Example 4> Graphitized particles A-5 used in Example 5 are the same as those shown in Table 1, except that the secondary firing temperature was changed. a-
Got 4. Table 1 shows the physical properties of the obtained graphitized particles a-4.

A developer carrying member C-4 was prepared in the same manner as in Example 1 except that the graphitized particles a-4 were used as the graphitized particles in the resin coating layer instead of A-1. The same evaluation as in Example 1 was performed. The formulation and physical properties of the resin coating layer of this developer carrying member are shown in Table 2, and the evaluation results are shown in Tables 3 and 4.

Example 8 In Example 1, the graphitized particles A-1 are the same as the graphitized particles A-1 except that the fine pulverization conditions of the bulk mesophase pitch of the raw material used and the classification conditions after the secondary firing are changed. The number average particle size is 13.2μ using the same method.
m graphitized particles A-8 were obtained. Resol type phenolic resin solution (containing 50% methanol) 200 parts Graphitized particles (A-8) 45 parts Conductive carbon black 5 parts Spherical particles a-7 (carbonized particles obtained by firing phenolic resin particles at 2200 ° C) 8 parts / methanol 130 parts To the above material, glass beads having a diameter of 1 mm were added as media particles and dispersed by a sand mill, and the solid content of the dispersion was diluted to 33% with methanol to obtain a coating solution.

Using this coating solution, a resin coating layer was formed by a spraying method on a ground aluminum cylindrical tube having an outer diameter of 20 mmφ and a center line average roughness Ra of 0.4 μm.
Then, it was heated in a hot air drying oven at 150 ° C. for 30 minutes to cure the resin coating layer to prepare a developer carrying member B-8.
Table 2 shows the formulation and physical properties of the resin coating layer of the resulting developer carrier B-8.

The developer carrying member B-8 is replaced with the image forming apparatus of FIG. 9 having the developing device of FIG. 7 (equipped with contact roller charging means and contact roller transfer means) LBP1910 (manufactured by Canon Inc.).
Then, the durability evaluation test was performed on 30,000 sheets of the developer carrying member while being mounted on the substrate and supplying the one-component developer. The following were used as the one-component developer. -Polyester resin 100 parts-Magnetite 100 parts-Al complex of di-tert-butyl salicylic acid 1 part-Low molecular weight polypropylene 5 parts The above materials were mixed by a Henschel mixer and melt-kneaded and dispersed by a twin-screw extruder mite. After cooling the kneaded material, it is roughly pulverized by a hammer mill, then finely pulverized by a jet stream type pulverizer, and then classified by an air stream type classifier to obtain a fine powder having a number average particle diameter of 5.8 μm (toner). Particles).

1.2 parts of hydrophobic colloidal silica treated with a silane coupling agent was externally added to 100 parts of this fine powder to obtain a magnetic toner, and this magnetic toner was used as a one-component developer. (Evaluation) A durability test was performed on the following evaluation items, and each developer carrying member of Examples and Comparative Examples was evaluated.

Image evaluation of image density, fog, sleeve ghost, blotch, halftone uniformity, etc., toner charge amount (Q / M) and toner transport amount (M / M) on the developer carrier.
S) and the abrasion resistance of the resin coating layer were evaluated by the same method as the evaluation method in Example 1. Further, the stain resistance of the resin coating layer of the developer carrying member was evaluated by the following method. For all evaluation items, 20 ° C / 60% room temperature and normal humidity (N / N) environment, 24 ° C
The durability was evaluated in a room temperature low humidity (N / L) environment of / 10% and a high temperature high humidity (H / H) environment of 32 ° C./80%. The results are shown in Tables 5 and 6. Good results were obtained for both the image and the durability.

(Staining resistance of resin coating layer) The surface of the developer bearing member after the durability test was observed at about 200 times with an ultra deep shape measuring microscope manufactured by KEYENCE, and the degree of toner contamination was determined according to the following criteria. Based on the evaluation. A: Only slight contamination is observed. B: Some contamination is observed. C: Contamination is partially observed. D: Significant contamination is observed.

[0218]

[Table 5]

[0219]

[Table 6]

<Example 9> Graphitized particles A-1 of Example 1
In the same manner, except that the fine pulverization conditions of the bulk mesophase pitch of the raw material used and the classification conditions after the secondary firing were changed, the graphitized particles A-9 having a number average particle size of 19.7 μm were used. Got

In Example 8, as the graphitized particles in the resin coating layer, the graphitized particles A-8 were used instead of the graphitized particles A-8.
A developer carrying member B-9 was produced in the same manner as in Example 8 except that -9 was used, and the same evaluation as in Example 8 was performed. The formulation and physical properties of the resin coating layer of this developer carrying member B-9 are shown in Table 2, and the evaluation results are shown in Tables 5 and 6.

<Comparative Example 5> As a raw material for the graphitized particles,
A mixture of coke and tar pitch is used, and the mixture is kneaded at a temperature equal to or higher than the softening point of the tar pitch, extruded, and primary-fired at 1000 ° C. in a nitrogen atmosphere for carbonization, followed by impregnation with coal tar pitch. After that, it is secondarily fired at 2800 ° C. in a nitrogen atmosphere, graphitized, further pulverized and classified to have a number average particle diameter of 13.6.
μm graphitized particles a-5 were obtained. Table 1 shows the physical properties of the graphitized particles a-5.

In Example 8, the graphitized particles a-5
Was used in place of A-8 as the graphitized particles in the resin coating layer, in the same manner as in Example 8 for the developer carrying member C-.
5 was produced. This developer carrying member C-5 was evaluated in the same manner as in Example 8. The formulation and physical properties of the resin coating layer of the developer carrying member C-5 are shown in Table 2, and the evaluation results are shown in Tables 5 and 6.
Shown in.

Comparative Example 6 Graphitized particles A-8 of Example 8
In the production of A, the graphitized particles a were prepared by using the same method except that the secondary firing temperature was changed as shown in Table 1.
-6 was obtained. Table 1 shows the physical properties of the obtained graphitized particles a-6. A developer carrying member C-6 was prepared in the same manner as in Example 8 except that the graphitized particles a-6 were used instead of A-8 as the graphitized particles in the resin coating layer. The same evaluation as was done.

The formulation and physical properties of the resin coating layer of this developer carrying member are shown in Table 2, and the evaluation results are shown in Tables 5 and 6. <Example 10> -Resol type phenolic resin solution (containing 50% methanol) 200 parts-graphitized particles (A-1) 36 parts-conductive carbon black 5 parts-methanol 120 parts Glass beads having a diameter of 1 mm were added to the above materials. It was added as media particles, dispersed with a sand mill, and the solid content of the dispersion was diluted to 35% with methanol to obtain a coating liquid.

Using this coating liquid, a resin coating layer was formed by a spray method on an aluminum cylindrical tube having an outer diameter of 32 mmφ and a center line average roughness Ra of 0.2 μm, which had been ground, and then a hot air drying furnace was used. The resin coating layer was cured by heating at 150 ° C. for 30 minutes to prepare a developer carrier B-10. Table 2 shows the formulation and physical properties of the resin coating layer of the resulting developer carrier B-10.

The developer carrying member B-10 was mounted on the image forming apparatus (equipped with corona charging means and corona transfer means) IR8500 (manufactured by Canon) of FIG. 9 having the developing device of FIG. While supplying the developer, a durability evaluation test was conducted on 800,000 sheets of the developer bearing member. The following were used as the one-component developer. -Styrene acrylic resin 100 parts-Magnetite 95 parts-Al complex of di-tert-butyl salicylic acid 2 parts-Low molecular weight polypropylene 4 parts The above materials were mixed by a Henschel mixer, and melt-kneaded and dispersed by a twin-screw extruder mite. . After cooling the kneaded product, roughly crushed with a hammer mill, further finely crushed with a mechanical crusher, and then classified using an airflow classifier,
A fine powder (toner particles) having a number average particle diameter of 6.3 μm was obtained.

To 100 parts of this fine powder, 1.2 parts of hydrophobic colloidal silica treated with a silane coupling agent and 3 parts of strontium titanate fine powder were externally added to obtain a magnetic toner, and this magnetic toner was used for one-component development. I used it as an agent. (Evaluation) A durability test was conducted on the following evaluation items,
The developer carrying members of Examples and Comparative Examples were evaluated.

Image evaluation of image density, fog, sleeve ghost, blotch, halftone uniformity, etc., toner charge amount (Q / M) and toner transport amount (M / M) on the developer carrier.
S), the abrasion resistance of the resin coating layer, and the stain resistance of the resin coating layer of the developer carrying member were evaluated by the same method as the evaluation method in Example 1. For all evaluation items, a room temperature and normal humidity (N / N) environment of 20 ° C / 60%, 2
4 ℃ / 10% room temperature and low humidity (N / L) environment, 32 ℃ / 80
The durability was evaluated in a high temperature and high humidity (H / H) environment of 100%. The results are shown in Tables 7 and 8. Good results were obtained for both the image and the durability.

[0230]

[Table 7]

[0231]

[Table 8]

<Examples 11 to 13> In Example 10, as the graphitized particles in the resin coating layer, graphitized particles A-
Developer carrying members B-11 to B-13 were prepared in the same manner as in Example 10 except that graphitized particles A-2 to A-4 were used instead of No. 1, respectively. Was evaluated. Table 2 shows the formulation and physical properties of the resin coating layers of these developer carrying members B-11 to B-13, and Tables 7 and 8 show the evaluation results.

<Comparative Examples 7 to 9> In Comparative Example 7 except that graphitized particles a-1 to a-3 were used in place of graphitized particles A-1 as the graphitized particles in the resin coating layer. Using the same method as in Example 10, developer carrying members C-7 to C-9
Was prepared and evaluated in the same manner as in Example 10. Table 2 shows the formulations and physical properties of the resin coating layers of these developer carrying members C-7 to C-9, and the evaluation results are shown in Tables 7 and 8.

[0234]

As described above, according to the present invention,
By having the resin coating layer on the surface of the developer carrier have a structure in which graphitized particles having a specific degree of graphitization and an indentation hardness value are dispersed in the resin, a uniform surface shape and lubricity can be obtained. While the resin coating layer is formed, it is possible to prevent the graphitized particles from being worn or separated from the surface of the resin coating layer. Further, even if the resin coating layer is worn, the graphitized particles are exposed again from the resin coating layer, so that the roughness of the surface coating layer of the developer carrying member, the uniformity of the surface shape, and the It is possible to prevent a change in the material composition of the surface and keep it substantially constant. Further, the resin coating layer containing the graphitized particles does not cause toner contamination or toner charge-up even under different environments, and can quickly and uniformly impart an appropriate charge amount to the toner.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a part of a developer carrying member of the present invention.

FIG. 2 is a schematic sectional view showing a part of a developer carrier of the present invention.

FIG. 3 is a schematic sectional view showing a part of a developer carrying member of the present invention.

FIG. 4 is a schematic sectional view showing a part of a developer carrying member of the present invention.

FIG. 5 is a schematic view showing an embodiment of the developing device of the present invention when a magnetic one-component developer is used.

FIG. 6 is a schematic view showing another embodiment of the developing device of the invention.

FIG. 7 is a schematic view showing another embodiment of the developing device of the invention.

FIG. 8 is a schematic diagram showing an embodiment of the developing device of the present invention when a non-magnetic one-component developer is used.

FIG. 9 is a schematic configuration diagram showing an example of an image forming apparatus of the present invention.

FIG. 10 is a schematic configuration diagram showing an example of a process cartridge of the present invention.

[Explanation of symbols]

1, 81, 101 Electrophotographic photosensitive drum (electrostatic latent image carrier) 2 Magnetic regulation blade (developer layer thickness regulating member) 3, 103 Hopper (developer container) 4, 104 Developer 5, 105 Magnet roller (magnet) ) 6,16 Metal cylindrical tube (base) 7,17 Resin coating layer 8,108 Development sleeve (developer carrier) 9,109 Development bias power source (bias means) 111 Elasticity regulation blade 120 Development means N1, N2, S1, S2, magnetic pole a Graphitized particles b Coating resin c Conductive fine particles d Spherical particles

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Satoshi Otake             Kyano, 3-30-2 Shimomaruko, Ota-ku, Tokyo             Within the corporation (72) Inventor Kyohisa Akashi             Kyano, 3-30-2 Shimomaruko, Ota-ku, Tokyo             Within the corporation (72) Inventor Kenji Fujishima             Kyano, 3-30-2 Shimomaruko, Ota-ku, Tokyo             Within the corporation (72) Inventor Ikki Saiki             Kyano, 3-30-2 Shimomaruko, Ota-ku, Tokyo             Within the corporation (72) Inventor Yasuhide Goseki             Kyano, 3-30-2 Shimomaruko, Ota-ku, Tokyo             Within the corporation F term (reference) 2H077 AC04 AD06 AD13 AD17 AD23                       AD24 AD36 AD37 AE03 AE04                       DB08 EA03 EA13 EA14 FA01                       FA12 FA19 FA22 FA27 GA13                 3J103 AA02 AA13 BA41 FA12 FA18                       GA02 GA57 GA58 HA03 HA12                       HA41

Claims (6)

[Claims] 1. A developer carrying body carrying a developer for visualizing an electrostatic latent image carried on an electrostatic latent image carrying body, wherein the developer carrying body is a substrate and a surface of the substrate. And a resin coating layer formed on the resin coating layer having a graphitization degree p (002) of 0.20 to 0.20.
0.95 and indentation hardness value HUT [68] is 1
A developer carrier comprising at least graphitized particles of 5 to 60. 2. The friction coefficient μs of the resin coating layer is 0.1.
The developer carrier according to claim 1, wherein 0 ≦ μs ≦ 0.35. 3. The developer carrier according to claim 1, wherein the graphitized particles are obtained by graphitizing mesocarbon microbead particles or bulk mesophase pitch particles. 4. The number average particle diameter of the graphitized particles is 0.5.
The developer carrying member according to any one of claims 1 to 3, wherein the developer carrying member has a thickness of 25 to 25 µm. 5. A developing device having a developer container containing a developer and a developer carrying member carrying the developer contained in the developer container in a layered manner, the developing device facing the electrostatic latent image carrying member. A developing device for transporting the carried developer to a region, and developing and visualizing the electrostatic latent image carried on the electrostatic latent image carrier by the carried developer, wherein the developer A developing device, wherein the carrier is the developer carrier according to any one of claims 1 to 4. 6. A toner image is formed by visualizing an electrostatic latent image formed on an electrostatic latent image carrier with a developer, and the toner image is transferred to a transfer material to form an image. A process cartridge detachably mounted on an image forming apparatus main body, the electrostatic latent image carrier for carrying an electrostatic latent image, and the electrostatic latent image is developed by a developer to form a developed image. And (i) charging means for charging the electrostatic latent image carrier, (ii) latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier,
(Iii) selected from a transfer means for transferring the developed image onto a transfer material, and (iv) a cleaning means for removing the transfer residual developer on the electrostatic latent image carrier, and supported integrally with the developing means. And at least one means, wherein the developing means has a developer container for containing a developer and the developer carrying member according to any one of claims 1 to 4. Process cartridge.