JPH08240981A - Developer carrying body, developing device, image forming device and process cartridge - Google Patents

Abstract

PURPOSE: To prevent deterioration of a conductive coating layer on the surface of a developer carrying body caused by repetition of copying or repeated use for a long time, to obtain high durability, and to obtain stable image quality by incorporating a binder resin and specified conductive spherical particles into the conductive coating layer. CONSTITUTION: The friction in magnetic toner particles and between the toner and a conductive coating layer 7 on a developing sleeve 8 produces triboelectric charge in the developer 4 to develop an electrostatic latent image on a photoreceptor drum 1. The conductive coating layer contains at least a binder resin and conductive spherical particles having 0.3-30μm number average particle size and <=3g/cm<3> true density dispersed in the binder resin. Thereby, uniform surface roughness is maintained on the surface of the conductive coating layer 7. Moreover, even when the surface of the conductive coating layer 7 is worn, the surface roughness on the conductive coating layer 7 is little changed and contamination with the toner or melt-sticking of the toner on the developer carrying body is hardly caused.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic method, in which an electrostatic latent image formed on an electrostatic latent image holding member such as an electrophotographic photosensitive member or an electrostatic recording dielectric is developed and visualized. The present invention relates to a developer carrier used for the above, and a developing device, an image forming apparatus, and a process cartridge in which the developer carrier is used.

[0002]

2. Description of the Related Art Conventionally, for example, as a developing device for visualizing an electrostatic latent image formed on a surface of a photosensitive drum as an electrostatic latent image holder with a magnetic toner as a one-component developer, for example, FIG. A device as shown in is known. In FIG. 6, a developer container 53 holds a magnetic toner 54 as a one-component developer, which causes friction between particles of the magnetic toner and a developing sleeve 58 as a developer carrier and magnetic toner particles. Due to the friction between them, the electrostatic latent image charge formed on the photosensitive drum 51 and the charge having a polarity opposite to that of the developing reference potential are applied to the magnetic toner particles, and the magnetic blade 52 moves the magnetic toner onto the developing sleeve 58 extremely. It is thinly applied and carried and conveyed to the developing area D formed by the photosensitive drum 51 and the developing sleeve 58, and is carried in the developing area D by the action of the magnetic field of the magnet 55 fixed in the developing sleeve 58. It is known that the magnetic toner that is ejected is made to fly to visualize the electrostatic latent image on the photosensitive drum 51. In addition, A and B indicate the respective rotating directions of the developing sleeve 58 and the photosensitive drum 51, 59 indicates a developing bias means for applying a developing bias voltage at the time of development, and 60 indicates a magnetic toner in the developer container 53. 54 is a stirring blade for stirring 54. However, when such a one-component developer is used, it is difficult to adjust the toner charge, and although various devises have been made depending on the developer, there are problems related to the non-uniformity of the toner charge and the durability stability of the charge. , Not completely resolved.

In particular, during repeated rotation of the developing sleeve, 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. The so-called charge-up phenomenon, in which the toner is attracted to the surface of the developing sleeve and becomes immobile and does not move from the developing sleeve to the latent image on the electrostatic latent image holder (drum), is apt to occur particularly under low humidity. When such a charge-up phenomenon occurs,
Since the toner in the upper layer is less likely to be charged and the developing amount of the toner is reduced, problems such as thin line images and low image density of solid images occur. Further, since the toner layer forming state of the image portion (toner consuming portion) and the non-image portion are different and the charging state is different, for example, the position where a solid image having a high image density is once developed is next to the developing sleeve. When the halftone image is developed at the developing position during rotation of, the so-called sleeve ghost phenomenon, in which a trace of a solid image appears on the image, easily occurs.

Recently, in order to further improve the image quality of electrophotography, the particle size and the particle size of the toner have been reduced. For example, in order to improve resolution and sharpness and faithfully reproduce a latent image, it is common to use a toner having a weight average particle size of about 6 to 9 μm. Further, the fixing temperature of the toner tends to be lowered for the purpose of shortening the first copy time and saving power. In such a situation, the toner is more likely to electrostatically adhere to the developing sleeve, and the external physical force is apt to cause contamination of the developing sleeve surface or toner fusion. ing.

As a method for solving such a phenomenon, a developing sleeve in which a coating layer in which a solid lubricant and a conductive fine powder such as carbon are dispersed in a resin is provided on a metal substrate is used in a developing device. A method has been proposed. It is recognized that by using this method, the above-mentioned phenomenon is significantly reduced. However, in this method, the surface of the developing sleeve becomes uneven in shape, so that uniform charging is still insufficient, and there is a problem in durability such as brittleness of the coating layer.

In Japanese Patent Laid-Open No. 3-200986, a developing sleeve is proposed in which a conductive lubricant powder such as a solid lubricant and carbon, and spherical particles are dispersed in a resin to provide a conductive coating layer on a metal substrate. Has been done. In this developing sleeve, the surface shape of the developing sleeve is made uniform, and the charging is made uniform and the abrasion resistance is improved. However, even in this developing sleeve, further improvement of durability performance such as improvement of abrasion resistance of the conductive coating layer and suppression of toner contamination and toner fusion when abrasion occurs is desired.

[0007]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to prevent repeated deterioration of the conductive coating layer on the surface of the developer carrier due to repeated copying or durability, to provide high durability and stable image quality. An object of the present invention is to provide an obtained developer carrier, a developing device having the developer carrier, an image forming apparatus, and a process cartridge. An object of the present invention is to provide a developer carrier capable of stably obtaining a high-quality image without causing problems such as density reduction, sleeve ghost, and fog over a long period of time even under different environmental conditions. To provide a developing device, an image forming device and a process cartridge having the developer carrying member. An object of the present invention is to suppress the uneven charging of the toner on the surface of the developer carrier, which appears when a toner having a small particle diameter is used, and to give a proper charge amount to the toner. To provide a developing device, an image forming device and a process cartridge having the developer carrying member.

[0008]

The above object can be achieved by the present invention described below. That is, the present invention relates to a developer carrier having at least a substrate and a conductive coating layer coating the substrate, and in the conductive coating layer, a binder resin and a number average dispersed in the binder resin. A developer carrier comprising at least conductive spherical particles having a particle size of 0.3 to 30 μm and a true density of 3 g / cm ³ or less, a developing device having the developer carrier, an image forming apparatus, and It is a process cartridge.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The developer carrying member of the present invention can be provided with a specific conductive coating layer on the surface of the developer carrying member, whereby the durability thereof can be remarkably improved as compared with the conventionally used one. Since it is difficult to cause deterioration such as abrasion and toner contamination of the conductive coating layer on the surface of the developer bearing member due to repeated copying or durability, it is possible to obtain high-quality images for a long time that image density is low, ghosts and fog are not likely to occur. Can be provided over.

The present invention will be described in detail below. First, the conductive spherical particles used in the conductive coating layer coated on the surface of the substrate constituting the developer carrier of the present invention will be described. The conductive spherical particles used in the present invention have a number average particle diameter of 0.3 to 30 μm and a true density of 3 g / cm ³ or less. By adding such conductive spherical particles, while maintaining a uniform surface roughness on the conductive coating layer surface in the developer carrier of the present invention, even if the conductive coating layer surface is worn, The change in the surface roughness of the coating layer is small, and it becomes difficult for toner contamination and toner fusion to occur on the developer carrying member.

The number average particle diameter of the conductive spherical particles used in the present invention is 0.3 to 30 μm, preferably 2 to 20 μm.
The ones are good. The number average particle diameter of the conductive spherical particles is 0.3.
When the thickness is less than μm, the effect of imparting uniform surface roughness to the surface of the conductive coating layer is small, and toner charge-up due to abrasion of the conductive coating layer, toner contamination and toner fusion occur, resulting in an image obtained. Since the deterioration due to the sleeve ghost and the decrease in image density are likely to occur, it is not preferable, and when the number average particle diameter exceeds 30 μm, the surface roughness of the conductive coating layer becomes too large and the toner is sufficiently charged. This is not preferable because it is difficult to be performed and the mechanical strength of the conductive coating layer is reduced.

The true density of the conductive spherical particles used in the present invention is 3 g / cm ³ or less, preferably 2.7 g / c.
m ³ or less, and more preferably 0.9 to 2.5 g / cm ³ . That is, the true density of the conductive spherical particles is 3 g /
When it exceeds ³ cm ³ , the dispersibility of the spherical particles in the conductive coating layer becomes insufficient, so that it becomes difficult to impart uniform roughness to the surface of the coating layer, and the toner is uniformly charged and the coating layer has a uniform charge. It is not preferable because the strength becomes insufficient.

The term "spherical" in the conductive spherical particles means that the ratio of major axis / minor axis of the particles is about 1.0 to 1.5, and in the present invention, the ratio of major axis / minor axis is preferably. Particles of 1.0 to 1.2, particularly spherical particles, are preferably used. When the ratio of the major axis / minor axis of the conductive spherical particles exceeds 1.5, the dispersibility of the conductive spherical particles in the conductive coating layer decreases and the roughness of the surface of the conductive coating layer becomes uneven. Therefore, it is not preferable in terms of uniform charging of the toner and strength of the conductive coating layer.

In the present invention, the electrically conductive spherical particles have a volume resistance of 10 ⁶ Ω · cm or less, preferably 10 ³ -10 ⁻⁶ Ω · cm.
Of particles are used. The volume resistance value of the conductive spherical particles is 10
If it exceeds ⁶ Ω · cm, the spherical particles exposed on the surface of the conductive coating layer due to abrasion tend to cause toner contamination and fusion, which is not preferable.

As the method for obtaining the conductive spherical particles used in the present invention, the following methods are preferable, but not limited thereto. As a method for obtaining particularly preferred conductive spherical particles used in the present invention,
For example, there may be mentioned a method of carbonizing and / or graphitizing resin-based spherical particles or mesocarbon microbeads to obtain spherical carbon particles of low concentration and good conductivity. Examples of the resin used for the resin-based spherical particles include phenol resin, naphthalene resin, furan resin, xylene resin, divinylbenzene polymer, styrene-divinylbenzene copolymer, and polyacrylonitrile. The mesocarbon microbeads can be usually produced by washing spherical crystals formed in the process of heating and firing the medium pitch with a large amount of a solvent such as tar, medium oil or quinoline.

As a more preferable method of obtaining conductive spherical particles, mechano-capsule particles such as phenol resin, naphthalene resin, furan resin, xylene resin, divinylbenzene polymer, styrene-divinylbenzene copolymer and polyacrylonitrile can be used. Examples include a method in which the bulk mesophase pitch is coated by a chemical method, and the coated particles are heat-treated in an oxidizing atmosphere and then fired to carbonize and / or graphitize to obtain conductive spherical carbon particles.

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

As another method for obtaining the conductive spherical particles used in the present invention, the conductive fine particles smaller than the particle diameter of the core particles are mechanically mixed with the core particles composed of the spherical resin particles in an appropriate mixing ratio. After the conductive fine particles are uniformly attached to the periphery of the core particles by the action of van der Waals force and electrostatic force, the local temperature rise caused by applying mechanical impact force Examples include a method of softening the surface of the core particle and forming conductive fine particles on the surface of the core particle to obtain conductive spherical resin particles.

For the core particles, it is preferable to use spherical resin particles made of an organic compound and having a low true density. Examples of the resin include PMMA, acrylic resin,
Examples thereof include polybutadiene resin, polystyrene resin, polyethylene, polypropylene, polybutadiene, or copolymers thereof, benzoguanamine resin, phenol resin, polyamide resin, nylon, fluorine resin, silicone resin, epoxy resin, polyester resin.
As the conductive fine particles (small particles) used when forming a film on the surface of the core particles (mother particles), the particle size of the small particles is smaller than that of the mother particles in order to uniformly provide the conductive fine particle coating. It is preferable to use one-eighth or less.

As still another method for obtaining the conductive spherical particles used in the present invention, the conductive spherical particles in which the conductive fine particles are dispersed by uniformly dispersing the conductive fine particles in the spherical resin particles are prepared. The method of obtaining is mentioned. As a method for uniformly dispersing the conductive fine particles in the spherical resin particles, for example, the binder resin and the conductive fine particles are kneaded to disperse the conductive fine particles, followed by cooling and solidification, and pulverization to a predetermined particle size. And to obtain conductive spherical particles by spheroidizing by mechanical and thermal treatments; or adding a polymerization initiator, conductive fine particles and other additives into a polymerizable monomer, and uniformly using a disperser. The dispersed monomer composition is suspended in an aqueous phase containing a dispersion stabilizer by a stirrer so as to have a predetermined particle size and polymerized to obtain spherical particles in which conductive particles are dispersed. There is a method.

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

It is preferable to disperse the lubricating particles in the conductive coating layer constituting the developer carrying member of the present invention in combination with the conductive spherical particles because the effect of the present invention is further promoted. Examples of the lubricating particles include graphite,
Examples of the particles include molybdenum disulfide, boron nitride, mica, graphite fluoride, silver-niobium selenide, calcium chloride-graphite, talc and fatty acid metal salts such as zinc stearate.
It is particularly preferably used because it does not impair the conductivity of the conductive coating layer when used in combination with the conductive spherical particles.

The number average particle diameter of the lubricating particles is preferably about 0.2 to 20 μm, more preferably 1 to 15 μm.
It is better to use m. When the number average particle diameter of the lubricating particles is less than 0.2 μm, it is difficult to obtain sufficient lubricity, which is not preferable, and when the number average particle diameter exceeds 20 μm, the surface roughness of the conductive coating layer is low. It becomes non-uniform, which is not preferable in terms of uniform charging of the toner and strength of the coating layer.

The conductive coating layer constituting the developer carrying member of the present invention is constituted by dispersing the conductive spherical particles or lubricating particles as described above in the binder resin. Examples of the binder resin material to be used include styrene resin, vinyl resin, polyether sulfone resin,
Thermoplastic resins such as polycarbonate resin, polyphenylene oxide resin, polyamide resin, fluororesin, fibrous resin and acrylic resin; epoxy resin, polyester resin, alkyd resin, phenol resin, melamine resin, polyurethane resin, urea resin, silicone resin And a heat or light curable resin such as a polyimide resin can be used. Among these, those having releasability such as silicone resin and fluorine resin, or polyether sulfone resin, polycarbonate resin, polyphenylene oxide resin, polyamide resin, phenol resin, polyester resin, polyurethane resin, styrene resin and acrylic resin. Those having excellent mechanical properties such as resins are more preferable.

In the present invention, the volume resistance of the conductive coating layer of the developer carrying member is preferably 10 ³ Ω · cm or less, more preferably 10 ³ to 10 ⁻² Ω · cm. When the volume resistance of the conductive coating layer exceeds 10 ³ Ω · cm, toner charge-up easily occurs,
It is easy to cause ghost deterioration and density reduction. In the present invention, in order to adjust the volume resistance of the conductive coating layer, other conductive fine particles may be dispersed and contained in the conductive coating layer in combination with the above-mentioned conductive spherical particles. The conductive fine particles have a number average particle diameter of preferably 1 μm or less, more preferably 0.01 to 0.8 μm. When the number average particle diameter of the conductive fine particles to be dispersedly contained in the conductive coating layer in combination with the conductive spherical particles exceeds 1 μm, it becomes difficult to control the volume resistance of the conductive coating layer to be low, and The charge-up phenomenon is likely to occur.

Examples of the conductive fine particles which 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; inorganic fillers such as graphite, conductive metal fibers and conductive carbon fibers.

Next, the structure of the developer carrying member of the present invention will be described. The developer carrying member of the present invention is mainly composed of a metal cylindrical tube as a base and a conductive coating layer surrounding and covering the metal cylindrical tube. Mainly, stainless steel and aluminum are preferably used for the metal cylindrical tube. The composition ratio of each component constituting the conductive coating layer will be described below, but these are particularly preferable ranges in the present invention.

The content of the conductive spherical particles dispersed in the conductive coating layer is preferably 2 to 120 parts by weight, more preferably 2 to 8 parts by weight with respect to 100 parts by weight of the binder resin.
A range of 0 parts by weight gives particularly favorable results. When the content of the conductive spherical particles is less than 2 parts by weight, the effect of adding the conductive spherical particles is small, and when the content exceeds 120 parts by weight, the chargeability of the toner may be too low.

When the lubricating particles are used in combination with the conductive spherical particles in the conductive coating layer, the content of the lubricating particles is preferably 5 to 120 parts by weight, based on 100 parts by weight of the binder resin. A range of 10 to 100 parts by weight preferably gives particularly preferable results. When the content of the lubricating particles exceeds 120 parts by weight, the film strength and the toner charge amount decrease, and when the content is less than 5 parts by weight, 7 μm.
When the following small particle size toner is used for a long time, the toner tends to be contaminated on the surface of the conductive coating layer.

1 μ in the case where the conductive fine particles are dispersed and contained in the conductive coating layer in combination with the conductive spherical particles.
The content of the conductive fine particles of m or less is as follows:
Particularly preferable results are obtained when it is used in an amount of preferably 40 parts by weight or less, more preferably 2 to 35 parts by weight, relative to 0 parts by weight. That is, the content of the conductive fine particles is 40
When the amount is more than parts by weight, the film strength and the toner charge amount are decreased, which is not preferable.

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

The layer thickness of the conductive coating layer having the above-mentioned constitution is preferably 25 μm or less, more preferably 20 μm.
Below, it is more preferably 4 to 20 μm to obtain a uniform layer thickness, but it is not particularly limited to this layer thickness. The thickness of these layers depends on the material used for the conductive coating layer, but is 4,000 to 20,0 as the attached weight.
It can be obtained by setting it to about 00 mg / m ² .

Next, the developing device, the image forming apparatus and the process cartridge of the present invention, in which the above-described developer carrying member of the present invention is incorporated, will be described. FIG. 1 shows a schematic view of a developing device of an embodiment having a developer carrying member of the present invention. In FIG. 1, an electrostatic latent image holder that holds an electrostatic latent image formed by a known process, for example, the electrophotographic photosensitive drum 1 is rotated in the arrow B direction. The developing sleeve 8 as a developer carrying member 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 expose the developing sleeve 8 and the photosensitive sleeve. The developer 4 is conveyed to the developing area D facing the drum 1. As shown in Figure 1,
Inside the developing sleeve 8, there is arranged a magnet roller 5 in which a magnet is inscribed 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 coated on a 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 the example of FIG. 1, in order to regulate the layer thickness of the developer 4 conveyed to the developing area D, the magnetic regulation blade 2 made of a ferromagnetic metal as a developer layer thickness regulating member is provided from the surface of the developing sleeve 8. It is suspended from the hopper 3 so as to face the developing sleeve 8 with a gap width of about 50 to 500 μm. By concentrating the magnetic force lines from the magnetic pole N1 of the magnet roller 5 on the magnetic regulation blade 2, a thin layer of the developer 4 is formed on the developing sleeve 8. 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 preferably thinner than the minimum gap between the developing sleeve 8 and the photosensitive drum 1 in the developing area D.

The developer carrier 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. To avoid complicated explanations,
In the following description, the non-contact type developing device as described above will be 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 DC 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 set to the developing sleeve 8. Is preferably applied to 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 attaching toner to the high potential portion of the electrostatic latent image having the high potential portion and the low potential portion, the electrostatic latent image is charged with a polarity opposite to that of the electrostatic latent image. Use toner. 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 any of these cases, the developer 4 is charged at least by friction with the developing sleeve 8.

FIG. 2 is a schematic configuration diagram showing another embodiment of the developing device of the present invention, and FIG. 3 is a schematic configuration diagram showing still another embodiment of the developing device of the present invention. In the developing device shown in FIGS. 2 and 3, urethane rubber is used as a developer layer thickness regulating member that regulates the layer thickness of the developer 4 on the developing sleeve 8.
An elastic regulating blade 11 made of an elastic plate made of a material having rubber elasticity such as silicone rubber or a material having metallic elasticity such as phosphor bronze or stainless steel is used. The elastic regulating blade 11 is used as a developing sleeve in the developing device of FIG. 8
The pressure is applied in the direction opposite to the rotational direction of the developing device of FIG. 3, and the developing device of FIG. 3 is characterized in that the elastic regulation blade 11 is pressed in the direction of the rotational direction of the developing sleeve 8 in the forward direction. In these developing devices, a thin layer of the developer is formed on the developing sleeve by elastically pressing the developer layer thickness regulating member to the developing sleeve 8 via the developer layer, so The above-mentioned FIG.
It is possible to form a thinner developer layer than in the case of the above cited reference.

The other basic structure of the developing device shown in FIGS. 2 and 3 is the same as that of the developing device shown in FIG. 1, and the same reference numerals indicate that they are basically the same members. 1 to 3 are merely schematic illustrations of the developing device of the present invention, in which the shape of the developer container (hopper 3) and the stirring blade 1 are shown.
It goes without saying that there are various forms of the presence or absence of 0 and the arrangement of magnetic poles. Of course, these devices can also be used for development using a two-component developer containing toner and carrier.

An example of an image forming apparatus using the developing device of the present invention illustrated in FIG. 3 will be described with reference to FIG. First, contact (roller) as primary charging means
The charging unit 119 charges the surface of the photosensitive drum 101 as an electrostatic latent image holder to a negative polarity, and exposes it with laser light 1
Image scanning by 15 forms a digital latent image on the photosensitive drum 101. Next, with a developing device having an elastic regulating blade 111 as a developer layer thickness regulating member, and a developing sleeve 108 as a developer carrying member 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. 4, in the developing area D, the photosensitive drum 1
The conductive substrate 01 is grounded, and the developing sleeve 10
Alternate bias, pulse bias and / or DC bias are applied to the bias voltage 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 photosensitive drum 10
The developed image (toner image) formed on the surface of No. 1 is transferred onto the recording material P by the contact transfer means 113. Next, the recording material P separated from the photosensitive drum 101 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 cleaned by 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. If necessary, the photosensitive drum 101 after cleaning is erased by erase exposure 116, 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 above series of steps, the photosensitive drum (that is, electrostatic latent image carrier) 101 has a photosensitive layer and a conductive substrate, and moves in the arrow direction. 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, is arranged so as not to rotate. The one-component developer 104 in the developer container 103 is applied and carried on the developing sleeve 108, and due to friction with the surface of the developing sleeve 108 and / or friction between the magnetic toners, for example, a negative triboelectric charge. Is given. Further, the elastic regulating blade 111 is provided so as to elastically press the developing sleeve 108, and the thickness of the developer layer is thin (30 μm 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 is made 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 f is 200-
It may be 4,000 Hz and V _pp is 500 to 3,000 V.

Developer (magnetic toner) in the development area D
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 a developing bias voltage such as an AC bias or a pulse bias.

Instead of the elastic regulating blade 111, it is also possible to use a magnetic doctor blade such as iron.
As the primary charging means, the charging roller 119 is used as the contact charging means as described above, but contact charging means such as a charging blade or charging brush may be used, or non-contact corona charging means may be used. However, the contact charging means is preferable in that ozone is less generated by charging. Further, as the transfer means, as described above, the transfer roller 1
Although the description has been made by using the contact transfer means such as No. 13, a non-contact corona transfer means may be used. However, also in this case, the contact transfer means is preferable in that ozone is less generated by transfer.

FIG. 5 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. 4 will be described using the same reference numerals as those in FIG. The process cartridge of the present invention is
At least the developing means and the electrostatic latent image holder are integrally formed into a cartridge, which is detachably attached to the main body of the image forming apparatus (for example, a copying machine, a laser beam printer, a facsimile machine).

In the embodiment shown in FIG. 5, the developing means 12
0, a drum-shaped electrostatic latent image holder (photosensitive drum) 101,
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 has an elastic regulation blade 111 and a one-component developer 104 having magnetic toner in the developer container 103.
During development, a predetermined electric field is formed between the photosensitive drum 101 and the developing sleeve 108 by the developing bias voltage from the bias applying means, and the developing process is performed.
In order to suitably carry out this developing step, the photosensitive drum 10
The distance between 1 and the developing sleeve 108 is very important.

In the above, the developing means 120, the electrostatic latent image holder 101, the cleaning means 118 and the primary charging means 1 are used.
Although the embodiment in which the four components of 19 are integrated into a cartridge has been described, in the present invention, at least two components of the developing unit and the electrostatic latent image holding member are integrated into a cartridge. 3 components including a developing unit, an electrostatic latent image holding member, and a cleaning unit, a developing unit, an electrostatic latent image holding member, and a primary charging unit.
It is also possible to add one component or other components to integrally form a cartridge.

Next, the developer (toner) used in the present invention to obtain a visible image from an electrostatic latent image will be described. The toner contained in the developer is roughly classified into a dry toner and a wet toner. However, since the wet toner has a large problem of solvent volatilization, the dry toner is predominant at present.
The toner is a fine powder in which materials such as a binder resin, a release agent, a charge control agent and a colorant are melt-kneaded, the melt is cooled and solidified and then crushed, and then classified to have a uniform particle size distribution. Is.

The binder resin used in the toner is, for example, a homopolymer of styrene such as styrene, α-methylstyrene, p-chlorostyrene and its substitution product; a styrene-propylene copolymer, a styrene-vinyltoluene copolymer. Polymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl copolymer, styrene-methyl methacrylate copolymer, styrene- Ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer Coal, styrene-isoprene copolymer, styrene Styrene-based copolymers such as styrene-maleic acid copolymer and styrene-maleic acid ester copolymer; polymethyl methacrylate; polybutyl methacrylate; polyvinyl acetate; polyethylene; polypropylene; polyvinyl butyral; polyacrylic acid resin; rosin; A modified rosin, a terpene resin, a phenol resin, an aliphatic or alicyclic hydrocarbon resin, an aromatic petroleum resin, a paraffin wax, and a carnauba wax can be used alone or in combination.

When the toner is used as a color toner (non-magnetic toner), the toner may contain a pigment as a colorant. Examples of pigments include carbon black, nigrosine dye, lamp black, Sudan black SM, fast 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, Rake Red C, Rhodamine F
B, Rhodamine B Lake, Methyl Violet B Lake, Phthalocyanine Blue, Pigment Blue, Brilliant Green B, Phthalocyanine Green, Oil Yellow GG, Pomelo First Yellow CG
G, Kayaset Y963, Kayaset YG, Pomelo Fast Orange RR, Oil Scarlet, Orazol Brown B, Pomelo First Scarlet C
G and oil pink OP can be mentioned, and it is possible to appropriately select and use from these.

When the toner is used as a magnetic toner, magnetic powder is contained in the toner. As such magnetic powder, a substance magnetized in a magnetic field is used. Examples of the magnetic powder include powders of ferromagnetic metals such as iron, cobalt, and nickel; alloys and compounds such as magnetite, hethamite, and ferrite. The content of these magnetic powders is 15 to 7 relative to the weight of the toner.
It is preferably about 0% by weight. There are cases where various release agents are added to the toner to be contained, and examples of such release agents include polyfluorinated ethylene, fluororesin, fluorocarbon oil, silicone oil, low molecular weight polyethylene, low molecular weight polypropylene and various types. Examples thereof include waxes. Further, if necessary, various charge control agents may be added to facilitate positive or negative charging.

In the present invention, the non-magnetic toner may be mixed with a carrier and used as a two-component developer.
Alternatively, it can be used as a non-magnetic one-component developer without mixing with a carrier. Furthermore, in the present invention,
The magnetic toner can be used as a one-component developer.

The methods for measuring physical properties relating to the present invention will be described below. (1) Measurement of center line average roughness (Ra) Based on the surface roughness of JIS B0601, a surf coder SE-3300 manufactured by Kosaka Laboratory was used to measure 3 points in the axial direction × 2 points in the circumferential direction = 6 points, respectively. , And took the average value.

(2) Measurement of volume resistance of particles A granular sample was placed in an aluminum ring of 40 mmφ and 2500
Pressure molding is performed with N, and the volume resistance value is measured using a 4-terminal probe with a resistivity meter Loresta AP or Hiresta IP (both manufactured by Mitsubishi Yuka). The measurement environment is 20-25
C and 50 to 60% RH.

(3) Measurement of volume resistance of coating layer A conductive coating layer having a thickness of 7 to 20 μm was formed on a PET sheet having a thickness of 100 μm, and the conductive coating layer of ASTM standard (D-991) was used.
-82) and Japan Rubber Association standard SRIS (2301
-1969), a voltage drop type digital ohmmeter (manufactured by Kawaguchi Denki Seisakusho) provided with electrodes of a four-terminal structure for measuring the volume resistance of conductive rubber and plastic. The measurement environment is 20 to 25 ° C, 50 to 60% R
H.

(4) Measurement of True Density of Spherical Particles The true density of the conductive spherical particles used in the present invention was measured using a dry densitometer Accupic 1330 (manufactured by Shimadzu Corporation). (5) Measurement of Particle Size of Spherical Particles A number average particle diameter calculated from the number distribution was obtained by measurement using a Coulter LS-130 type particle size distribution meter (manufactured by Coulter) of a laser diffraction type particle size distribution meter.

(6) Particle size measurement of conductive fine particles The particle size of the conductive fine particles is measured with an electron microscope.
The shooting magnification is 60,000, but if it is difficult, the photograph is enlarged at a low magnification and then the photograph is enlarged to 60,000. 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.

(7) Adhesion Weight of Conductive Coating Layer Using an electronic balance, the total weight of the developer carrying body before and after forming the conductive coating layer on the developer carrying body was measured, and the weight difference was calculated from the weight difference. The adhesion weight of the conductive coating layer was determined.

(8) Measurement of Toner Particle Diameter The toner particle diameter was measured using a Multisizer II Coulter Counter (manufactured by Coulter Co.) to obtain a weight-based weight average diameter obtained from the volume distribution. As described above, according to the present invention, the durability is improved as compared with the conventionally used developer carrier, and it becomes possible to maintain a state in which a good image can be provided for a long time. Therefore, according to the present invention,
A highly durable developer carrier that does not cause deterioration such as abrasion of the conductive coating layer on the surface of the developer carrier due to repeated copying or durability and toner contamination, and high quality that does not cause deterioration of image density, ghost, or fog. Such images can be provided for a long time.

[0060]

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 by weight unless otherwise specified. <Example 1> As a conductive spherical particle, a number average particle diameter of 10
14 parts by weight of coal-based bulk mesophase pitch powder having a number average particle size of 3 μm or less was uniformly coated on 100 parts of a spherical phenol resin having a particle size of 3 μm using a Reika machine (automatic mortar, manufactured by Ishikawa Plant), and then under an oxidizing atmosphere. Spherical conductive carbon particles (conductive spherical particles A-1) obtained by graphitizing by firing at 2,200 ° C. after heat stabilization treatment were used. Table 1 shows the physical properties of the conductive spherical particles A-1.・ Resol type phenol resin solution (containing 50% methanol) 200 parts ・ Number average particle size 6.1 μm graphite 45 parts ・ Conductive carbon black 5 parts ・ Isopropyl alcohol 130 parts Zirconia beads with a diameter of 1 mm as media particles In addition, the mixture was dispersed in a sand mill for 2 hours, and zirconia beads were separated using a sieve to obtain a stock solution B-1.

In 380 parts of the stock solution of B-1 obtained above,
10 parts of conductive spherical particles A-1 were added, and the solid content concentration was 3
After adding isopropyl alcohol to 2%,
The glass beads having a diameter of 3 mm were dispersed for 1 hour, and the glass beads were separated using a sieve to obtain a coating liquid. By using this coating solution, a conductive coating layer is formed with a coating width of 216 mm on an aluminum cylindrical tube having an outer diameter of 16 mmφ by a spray method, and then the conductive coating layer is heated in a hot air drying furnace at 150 ° C. for 30 minutes. The layer is cured to form a developer carrier C-
1 was produced. The adhesion weight of the conductive coating layer after drying is 10
It was 0 mg and the layer thickness was 8 μm. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member C-1.

A C-1 developer carrier is used as an image forming apparatus shown in FIG. 4 having the developing apparatus shown in FIG. 3, and a laser beam printer Laser Jet III Si (manufactured by Hewlett Packard) is used to produce a one-component developer. While supplying, a durability evaluation test of the developer carrying member was performed. The following were used as the one-component developer.・ Styrene-acrylic resin 100 parts ・ Magnetite 80 parts ・ 3,5-di-tert-butyl chromium salicylate complex 2 parts ・ Low molecular weight polypropylene 4 parts The above materials are kneaded, pulverized and classified by a general dry toner manufacturing method. Then, a fine powder (toner particles) having a number average particle diameter of 6.9 μm was obtained. To 100 parts of this fine powder, 1.0 part of hydrophobic colloidal silica was externally added to obtain a magnetic toner, and the magnetic toner was used as a one-component developer. In the image forming apparatus used in this embodiment, a process cartridge in which an electrostatic latent image holding member, a developing unit, a cleaning unit and a primary charging unit are integrally made into a cartridge is detachably mounted in the image forming apparatus main body. It has the configuration shown in.

Example 2 As conductive spherical particles, 100 parts of spherical phenol resin having a number average particle diameter of 4.8 μm,
14 parts of coal-based bulk mesophase pitch powder having a number average particle size of 1 μm or less was uniformly coated using a Reiki machine (automatic mortar, manufactured by Ishikawa Plant), and heat-stabilized in an oxidizing atmosphere at 2,200 ° C. Spherical conductive carbon particles obtained by graphitizing by firing (conductive spherical particles A-
2) was used. Table 1 shows the physical properties of the conductive spherical particles A-2. A developer carrying member C-2 was prepared in the same manner as in Example 1 except that 25 parts of the conductive spherical particles A-2 were added to 380 parts of the stock solution of B-1 produced in Example 1. The adhesion weight of the conductive coating layer after drying was 105 mg, and the layer thickness was 8 μm.
Met. . Table 2 shows the physical properties of the conductive coating layer of the developer carrying member C-2. A C-2 developer carrier was used in the same image forming apparatus as in Example 1, and a durability evaluation test of the developer carrier was performed while supplying a one-component developer as in Example 1.

Example 3 As conductive spherical particles, 100 parts of spherical phenol resin having a number average particle diameter of 26 μm was used with a Laika machine (automatic mortar, manufactured by Ishikawa Factory) to obtain a coal-based bulk having a number average particle diameter of 4 μm or less. Mesophase pitch powder 1
Spherical conductive carbon particles (conductive spherical particles A-, obtained by uniformly coating 4 parts, heat-stabilizing in an oxidizing atmosphere, and then graphitizing by firing at 2,200 ° C.)
3) was used. Table 1 shows the physical properties of the conductive spherical particles A-3. A developer carrying member C-3 was produced in the same manner as in Example 1 except that 6 parts of the conductive spherical particles A-3 were added to 380 parts of the stock solution of B-1 produced in Example 1. The adhesion weight of the conductive coating layer after drying was 100 mg, and the layer thickness was 8 μm.
Met. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member C-3. A C-3 developer carrier was used in the same image forming apparatus as in Example 1, and a durability evaluation test of the developer carrier was performed while supplying a one-component developer as in Example 1.

Example 4 As conductive spherical particles, 100 parts of a spherical phenol resin having a number average particle diameter of 10 μm and 14 parts of coal-based bulk mesophase pitch powder having a number average particle diameter of 3 μm or less were used in the same manner as in Example 1. Spherical conductive carbon particles obtained by uniformly coating using a machine (auto mortar, manufactured by Ishikawa Factory), heat-stabilizing in an oxidizing atmosphere, and then carbonizing by firing at 1,000 ° C. ( Conductive spherical particles A-4) were used. Table 1 shows the physical properties of the conductive spherical particles A-4. Stock solution of B-1 prepared in Example 1 38
A developer carrying member C-4 was prepared in the same manner as in Example 1 except that 10 parts of the conductive spherical particles A-4 was added to 0 part.
The dry weight of the conductive coating layer after drying was 95 mg, and the layer thickness was 8 μm. . Table 2 shows the physical properties of the conductive coating layer of the developer carrying member C-4. A C-4 developer carrier was used in the same image forming apparatus as in Example 1, and a durability evaluation test of the developer carrier was performed while supplying a one-component developer as in Example 1.

<Embodiment 5> As a conductive spherical particle, a spherical phenol resin having a number average particle diameter of 10.0 μm is heat-stabilized as it is in an oxidizing atmosphere and then calcined at 2,200 ° C. for graphitization. The obtained spherical conductive carbon particles (conductive spherical particles A-5) were used. Table 1 shows the physical properties of the conductive spherical particles A-5. B produced in Example 1
Developer carrier C- in the same manner as in Example 1 except that 10 parts of conductive spherical particles A-5 were added to 380 parts of the stock solution of -1.
5 was produced. The adhesion weight of the conductive coating layer after drying is 10
It was 0 mg and the layer thickness was 8 μm. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member C-5. Using the C-5 developer carrier in the same image forming apparatus as in Example 1,
While supplying the one-component developer in the same manner as in Example 1, a durability evaluation test of the developer carrying member was performed.

Example 6 As conductive spherical particles, spherical phenol resin having a number average particle size of 10.3 μm was heat-stabilized as it was in an oxidizing atmosphere and then carbonized by firing at 1,000 ° C. The obtained spherical conductive carbon particles (conductive spherical particles A-6) were used. Table 1 shows the physical properties of the conductive spherical particles A-6. B- produced in Example 1
1 part of A-6 as a conductive spherical particle was added to 380 parts of the stock solution of 1.
A developer carrying member C-6 was produced in the same manner as in Example 1 except that 0 part was added. The dry weight of the conductive coating layer after drying was 95 mg, and the layer thickness was 8 μm. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member C-6. C-6
While using the developer carrier of No. 1 in the same image forming apparatus as in Example 1, while supplying the one-component developer as in Example 1,
A durability evaluation test of the developer bearing member was performed.

Example 7 As electrically conductive spherical particles, spherical divinylbenzene polymer 1 having a number average particle size of 10.2 μm was used.
After 00 parts were uniformly coated with 14 parts by weight of petroleum-based bulk mesophase pitch powder having a number average particle size of 3 μm or less using a Laikai machine (automatic mortar, manufactured by Ishikawa Plant), and heat-stabilized in an oxidizing atmosphere. Spherical conductive carbon particles (conductive spherical particles A-7) obtained by graphitizing by firing at 2,000 ° C. were used. Table 1 shows the physical properties of the conductive spherical particles A-7. Stock solution of B-1 prepared in Example 1 38
A developer carrying member C-7 was produced in the same manner as in Example 1 except that 10 parts of the conductive spherical particles A-7 was added to 0 part.
The adhesion weight of the conductive coating layer after drying was 105 mg,
The layer thickness was 8 μm. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member C-7. A C-7 developer carrier was used in the same image forming apparatus as in Example 1, and a durability evaluation test of the developer carrier was performed while supplying a one-component developer as in Example 1.

<Example 8> As conductive spherical particles, 100 parts of the conductive spherical particles A-4 used in Example 4 were added.
Metal-coated carbon particles (conductive spherical particles A-8) plated with 100 parts of copper and silver were used. Table 1 shows the physical properties of the conductive spherical particles A-8. Stock solution of B-1 prepared in Example 1 3
A developer carrying member C-8 was produced in the same manner as in Example 1 except that 10 parts of the conductive spherical particles A-8 were added to 80 parts. The dry weight of the conductive coating layer after drying was 110 mg, and the layer thickness was 9 μm. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member C-8. A C-8 developer carrier was used in the same image forming apparatus as in Example 1, and a durability evaluation test of the developer carrier was performed while supplying a one-component developer as in Example 1.

<Example 9> As a conductive spherical particle, a number average particle diameter of 1 was obtained by using a hybridizer (manufactured by Nara Machine Co., Ltd.).
The spherical conductive-treated resin particles (conductive spherical particles A-9) obtained by coating 100 parts of 1.5 μm spherical PMMA particles with 5 parts of conductive carbon black were used. Table 1 shows the physical properties of the conductive spherical particles A-9. In the same manner as in Example 1 except that 10 parts of the conductive spherical particles A-9 were added to 380 parts of the stock solution of B-1 produced in Example 1,
A developer carrying member C-9 was prepared. The dry weight of the conductive coating layer after drying was 100 mg, and the layer thickness was 8 μm. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member C-9. A C-9 developer carrier was used in the same image forming apparatus as in Example 1, and a durability evaluation test of the developer carrier was performed while supplying a one-component developer as in Example 1.

<Example 10> As the conductive spherical particles, a hybridizer (manufactured by Nara Machinery Co., Ltd.) was used to coat 100 parts of spherical PMMA particles having a number average particle diameter of 11.5 μm with 20 parts of conductive zinc oxide fine particles. The spherical conductive-treated resin particles (conductive spherical particles A-10) thus obtained were used. Table 1 shows the physical properties of the conductive spherical particles A-10. A developer carrying member C-10 was produced in the same manner as in Example 1 except that 10 parts of the conductive spherical particles A-10 were added to 380 parts of the stock solution of B-1 produced in Example 1. The dry weight of the conductive coating layer after drying was 105 mg, and the layer thickness was 8 μm. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member C-10. A C-10 developer carrier was used in the same image forming apparatus as in Example 1, and a durability evaluation test of the developer carrier was performed while supplying a one-component developer as in Example 1.

Example 11 As a conductive spherical particle, a hybridizer (manufactured by Nara Machinery Co., Ltd.) was used, and 100 parts of spherical nylon particles having a number average particle diameter of 11.0 μm were added to graphite 18 having a number average particle diameter of 1 μm or less. Spherical conductive-treated resin particles (conductive spherical particles A-11) obtained by coating a part were used. Table 1 shows the physical properties of the conductive spherical particles A-11. A developer carrying member C-11 was produced in the same manner as in Example 1 except that 10 parts of the conductive spherical particles A-11 were added to 380 parts of the stock solution of B-1 produced in Example 1.
The adhesion weight of the conductive coating layer after drying was 100 mg,
The layer thickness was 8 μm. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member C-11. Using the C-11 developer carrier in the same image forming apparatus as in Example 1, a durability evaluation test of the developer carrier was performed while supplying a one-component developer as in Example 1.

Example 12 The following materials were used as the conductive spherical particles, kneading, pulverizing and classifying to obtain conductive particles having a number average particle diameter of 15.6 μm, and then the hybridizer (Nara Machine Co., Ltd.) was used. Conductive spherical resin particles (conductive spherical particles A) obtained by performing a spheroidizing treatment using
-12) was used. Table 1 shows the physical properties of the conductive spherical particles A-12. -Styrene-dimethylaminoethyl methacrylate-divinylbenzene copolymer (copolymerization ratio; 90: 10: 0.05) 100 parts-Conductive carbon black 25 parts To 380 parts of the stock solution of B-1 produced in Example 1, A developer carrying member C-12 was produced in the same manner as in Example 1 except that 10 parts of the conductive spherical particles A-12 were added. The dry weight of the conductive coating layer after drying was 95 mg, and the layer thickness was 8 μm. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member C-12. A C-12 developer carrier was used in the same image forming apparatus as in Example 1, and a durability evaluation test of the developer carrier was performed while supplying a one-component developer as in Example 1.

Example 13 The following materials were used as the conductive spherical particles, kneading, pulverizing and classifying to obtain conductive particles having a number average particle diameter of 13.1 μm, and then the hybridizer (Nara Machine Co., Ltd.) was used. Conductive spherical resin particles (conductive spherical particles A) obtained by performing a spheroidizing treatment using
-13) was used. Table 1 shows the physical properties of the conductive spherical particles A-13. -Styrene-dimethylaminoethyl methacrylate-divinylbenzene copolymer (copolymerization ratio; 90: 10: 0.05) 100 parts-Conductive titanium oxide 50 parts To 380 parts of the stock solution of B-1 produced in Example 1, A developer carrying member C-13 was produced in the same manner as in Example 1 except that 10 parts of the conductive spherical particles A-13 were added. The adhesion weight of the conductive coating layer after drying was 100 mg, and the layer thickness was 8 μm.
Met. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member C-13. The developer carrier of C-13 was used in Example 1.
Using the same image forming apparatus as in Example 1, a durability evaluation test of the developer carrying member was performed while supplying a one-component developer as in Example 1.

Example 14 The following materials were used as the conductive spherical particles, kneading, pulverizing and classifying to obtain conductive particles having a number average particle size of 10.5 μm, and then the hybridizer (Nara Machine Co., Ltd.) was used. Conductive spherical resin particles (conductive spherical particles A) obtained by performing a spheroidizing treatment using
-14) was used. Table 1 shows the physical properties of the conductive spherical particles A-14. -Styrene-dimethylaminoethyl methacrylate-divinylbenzene copolymer (copolymerization ratio; 90: 10: 0.05) 100 parts-Silver fine particles 50 parts Conductivity was added to 380 parts of the stock solution of B-1 produced in Example 1. A developer carrying member C-14 was produced in the same manner as in Example 1 except that 10 parts of the spherical particles A-14 were added. The adhesion weight of the conductive coating layer after drying was 105 mg, and the layer thickness was 8 μm.
Met. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member C-14. A C-14 developer carrier is used in Example 1.
Using the same image forming apparatus as in Example 1, a durability evaluation test of the developer carrying member was performed while supplying a one-component developer as in Example 1.

Example 15 Resol type phenolic resin solution (containing 50% methanol) 200 parts Conductive carbon black 20 parts Isopropyl alcohol 130 parts Zirconia beads having a diameter of 1 mm were added as media particles to the above material, and the mixture was placed in a sand mill. And dispersed for 2 hours, and zirconia beads were separated using a sieve to obtain a stock solution B-2.
10 parts of the conductive spherical particles A-1 were added to 380 parts of the stock solution of B-2.
A developer carrying member C was prepared in the same manner as in Example 1 except for adding a part of
-15 was produced. The dry weight of the conductive coating layer after drying was 100 mg, and the layer thickness was 8 μm. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member C-15. C
Using the developer carrier of No. -15 in the same image forming apparatus as in Example 1, a durability evaluation test of the developer carrier was performed while supplying the one-component developer as in Example 1.

<Example 16> 200 parts of PMMA resin solution (containing 50% toluene) 45 parts of graphite having a number average particle size of 6.1 μm 5 parts of conductive carbon black 130 parts of toluene Zirconia having a diameter of 1 mm Beads were added as media particles and dispersed in a sand mill for 2 hours, and zirconia beads were separated using a sieve to obtain stock solution B-3.
10 parts of the conductive spherical particles A-1 were added to 380 parts of the stock solution of B-3.
A developer carrying member C-16 was produced in the same manner as in Example 1 except that part addition was carried out. The dry weight of the conductive coating layer after drying was 105 mg, and the layer thickness was 8 μm. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member C-16.
A C-16 developer carrier was used in the same image forming apparatus as in Example 1, and a durability evaluation test of the developer carrier was performed while supplying a one-component developer as in Example 1.

Example 17 Resol type phenolic resin solution (containing 50% methanol) 200 parts Graphite having a number average particle size of 1.5 μm 30 parts Conductive carbon black 5 parts Isopropyl alcohol 130 parts 1 mm zirconia beads were added as media particles and dispersed for 2 hours with a sand mill, and the zirconia beads were separated using a sieve to obtain a stock solution B-4.

15 parts of the conductive spherical particles A-2 used in Example 2 were added to 380 parts of the stock solution of B-4, and isopropyl alcohol was added so that the solid content concentration became 32%, and then the diameter was 3 mm. Disperse using glass beads for 1 hour,
The glass beads were separated using a sieve to obtain a coating solution.
By using this coating solution, a conductive coating layer having a coating width of 310 mm was formed on an aluminum cylindrical tube having an outer diameter of 32 mmφ by a spray method.
The conductive coating layer was cured by heating for 0 minutes to prepare a developer carrier C-17. The dry weight of the conductive coating layer after drying was 265 mg, and the layer thickness was 7 μm. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member C-17.

The C-17 developer carrier is used in the image forming apparatus (corona charging means, corona transfer means) NP6060 (manufactured by Canon Inc.) having the developing device shown in FIG. While supplying, the durability evaluation test of the developer carrying member was performed. The following were used as the one-component developer.・ Polyester resin 100 parts ・ Magnetite 100 parts ・ 3,5-di-tert-butylsalicylic acid chromium complex 2 parts ・ Low molecular weight polypropylene 4 parts The above materials were kneaded, pulverized and classified by a general dry toner manufacturing method, Fine powder (toner particles) having an average particle diameter of 6.6 μm was obtained. 1.2 parts of hydrophobic colloidal silica 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.

<Comparative Example 1> In 380 parts of the stock solution of B-1 produced in Example 1, instead of the conductive spherical particles A-1, the amorphous graphite a-having a number average particle diameter of 17.0 μm was used.
A developer carrying member D-1 was produced in the same manner as in Example 1 except that 10 parts of 1 was added. The dry weight of the conductive coating layer after drying was 100 mg, and the layer thickness was 8 μm. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member D-1. Using the developer carrier D-1 in the same image forming apparatus as in Example 1, a durability evaluation test of the developer carrier was performed while supplying a one-component developer as in Example 1.

Comparative Example 2 In 380 parts of the stock solution of B-1 produced in Example 1, spherical particles having a number average particle size of 11.5 μm and having no conductivity were used instead of the conductive spherical particles A-1. P
A developer carrying member D-2 was produced in the same manner as in Example 1 except that 10 parts of MMA particles a-2 were added. The dry weight of the conductive coating layer was 100 mg and the layer thickness was 8 μm.
It was m. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member D-2. Using the developer carrier of D-2 in the same image forming apparatus as in Example 1, a durability evaluation test of the developer carrier was performed while supplying a one-component developer as in Example 1.

<Comparative Example 3> As conductive spherical particles, 100 parts of spherical phenol resin having a number average particle diameter of 37 μm was used with a Reika machine (automatic mortar, manufactured by Ishikawa Plant) to produce a coal-based bulk mesophase having a number average particle diameter of 4 μm or less. Pitch powder 16
The spherical conductive carbon particles (conductive spherical particles a-3) obtained by uniformly coating the parts and heat-stabilizing in an oxidizing atmosphere and then graphitizing by firing at 2,200 ° C. are used. I was there. The physical properties of the conductive spherical particles a-3 are shown in Table 1. The number average particle diameter of the conductive spherical particles a-3 is 35 μm.
Met. Developer in the same manner as in Example 1 except that 5 parts of conductive spherical particles a-3 were added to 380 parts of the stock solution of B-1 produced in Example 1 instead of the conductive spherical particles A-1. Carrier D-3 was prepared. The dry weight of the conductive coating layer after drying was 105 mg, and the layer thickness was 8 μm.
Table 2 shows the physical properties of the conductive coating layer of the developer carrying member D-3. Using the developer carrying member of D-3 in the same image forming apparatus as in Example 1, a durability evaluation test of the developer carrying member was performed while supplying a one-component developer as in Example 1.

<Comparative Example 4> As the conductive spherical particles, a number average particle diameter of 0.
Electrically treated spherical resin particles (conductive spherical particles a-4) obtained by coating 25 parts of conductive carbon black on 100 parts of 19 μm spherical PMMA particles were used. The physical properties of the conductive spherical particles a-4 are shown in Table 1, and the number average particle diameter of the conductive spherical particles a-4 was 0.23 μm. In the same manner as in Example 1 except that 35 parts of the conductive spherical particles a-4 were added to 380 parts of the stock solution of B-1 produced in Example 1 instead of the conductive spherical particles A-1, the developer loading was carried out. Body D-4
Was produced. The adhesion weight of the conductive coating layer after drying is 105
mg and the layer thickness was 8 μm. Table 2 shows the physical properties of the conductive coating layer of this developer carrying member D-4. Using the developer carrying member of D-4 in the same image forming apparatus as in Example 1, a durability evaluation test of the developer carrying member was conducted while supplying a one-component developer as in Example 1.

<Comparative Example 5> As the conductive spherical particles, the following materials were kneaded, pulverized and classified to give a number average particle diameter of 1
Conductive spherical resin particles (conductive spherical particles a-5) obtained by performing a spheroidizing treatment using a hybridizer (manufactured by Nara Machine Co., Ltd.) after obtaining 0.7 μm conductive particles.
Was used. The physical properties of the conductive spherical particles a-5 are shown in Table 1, and the true density was 3.35 g / cm ³ . -Styrene-dimethylaminoethyl methacrylate-divinylbenzene copolymer (copolymerization ratio; 90: 10: 0.05) 100 parts-Silver fine particles 300 parts Conductivity was applied to 380 parts of the stock solution of B-1 produced in Example 1. Instead of the spherical particles A-1, 10 conductive spherical particles a-5 were used.
A developer carrying member D-5 was produced in the same manner as in Example 1 except that part addition was carried out. The dry weight of the conductive coating layer after drying was 105 mg, and the layer thickness was 8 μm. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member D-5. D-
While using the developer carrier of No. 5 in the same image forming apparatus as in Example 1, while supplying the one-component developer as in Example 1,
A durability evaluation test of the developer bearing member was performed.

<Comparative Example 6> As the conductive spherical particles, the following materials were kneaded, pulverized and classified to give a number average particle diameter of 1
Conductive amorphous particles a-6 having a size of 5.6 μm were obtained. Table 1 shows the physical properties of the electrically conductive irregular-shaped particles a-6. -Styrene-dimethylaminoethyl methacrylate-divinylbenzene copolymer (copolymerization ratio; 90: 10: 0.05) 100 parts-Conductive carbon black 25 parts Next, stock solution 380 of B-1 prepared in Example 1 In place of the conductive spherical particles A-1, conductive amorphous particles a-6
A developer carrying member D-6 was produced in the same manner as in Example 1 except that 10 parts of was added. The dry weight of the conductive coating layer after drying was 95 mg, and the layer thickness was 8 μm. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member D-6.
Using the developer carrier of D-6 in the same image forming apparatus as in Example 1, a durability evaluation test of the developer carrier was performed while supplying a one-component developer as in Example 1.

<Comparative Example 7> B-4 produced in Example 17
In 380 parts of the stock solution of, instead of the conductive spherical particles A-2,
Amorphous graphite with a number average particle size of 4.0 μm
A developer carrying member D-7 was produced in the same manner as in Example 17, except that the addition of a part was added. The dry weight of the conductive coating layer after drying was 270 mg and the layer thickness was 7 μm. Table 2 shows the physical properties of the conductive coating layer of the developer carrying member D-7. D
Using the developer carrier of -7 in the same image forming apparatus as in Example 17, the durability evaluation test of the developer carrier was performed while supplying the one-component developer in the same manner as in Example 17.

[0088]

[Evaluation] A durability test was conducted on the following evaluation items,
The developer carrying members of Examples and Comparative Examples were evaluated. Table 3 shows the evaluation results of the durability of image density, durability fog and durability ghost under low temperature and low humidity. Also, in Table 4,
The evaluation results of durability of image density under high temperature and high humidity, durability fog and durability ghost are shown. Furthermore, Table 5 shows the evaluation results of abrasion resistance and stain resistance.

The number of durable sheets is Examples 1 to 16 and Comparative Example 1
For Nos. 6 to 40, the number of sheets was up to 40,000, and the measurement was performed during 10 sheets and 20,000 sheets endurance. In addition, in the case of Example 17 and Comparative Example 7, the number of sheets was up to 400,000, and the measurement was performed even when 10 sheets and 200,000 sheets were endured. Durable environments include low temperature / low humidity (L / L) and high temperature / high humidity (H /
H) The two lower endurance environments were performed. In particular,
Low temperature / low humidity (L / L) under the environment of 15 ° C / 10% RH, high temperature / high humidity (H / H) under 32.5 ° C / 85
% RH.

(1) Image Density (Durability Density) Using a reflection densitometer RD918 (manufactured by Macbeth), the density of solid black portions when solid printing was carried out was measured at 5 points, and the average value was used as the image density.

(2) Fog Density (Durability Fog) The reflectance (D ₁ ) of the solid white part of the recording paper on which the image was formed was measured, and the recording paper of the same cut as the recording paper used for the image formation Measure the reflectance (D ₂ ) and set the value of D ₁ -D ₂ to 5
The points were determined, and the average value was used as the fog density. The reflectance is TC
It was measured by -6DS (manufactured by Tokyo Denshoku).

(3) Ghost (durability ghost) The position of the developing sleeve for developing the image in which the solid white portion and the solid black portion are adjacent to each other comes to the developing position when the developing sleeve is rotated next time, and the halftone image is developed. Then, the difference in shade appearing on the halftone image was visually evaluated based on the following criteria. ○: No difference in light and shade is seen. ○ △: A slight difference in shade is seen. Δ: Practical is acceptable although there is a slight difference in shade. Poor: Practical use is not possible because the difference in light and shade is remarkable.

(4) Abrasion resistance of conductive coating layer Center line average roughness (Ra) of the surface of the developer carrier before and after endurance
Was measured.

(5) Contamination resistance of the conductive coating layer The surface of the developer bearing member after the durability was observed by SEM, and the degree of toner contamination was evaluated based on the following criteria. ○: Only slight contamination is observed. ○ △: Some contamination is observed. Δ: Contamination is partially observed. X: Significant contamination is observed.

Table 1 Physical properties of added particles constituting the conductive coating layer

Table 2 Physical properties of conductive coating layer of developer carrier

Table 3 Evaluation results (durability concentration, durability fog, durability ghost under low temperature and low humidity)

Table 4 Evaluation results (durability concentration, durability fog, durability ghost under high temperature and high humidity)

Table 5 Evaluation results (wear resistance, stain resistance)

[0100]

As described above, according to the present invention, the durability is improved as compared with the conventionally used developer carrying member,
It is possible to maintain a state in which a good image can be provided for a long time. Therefore, according to the present invention, due to the highly durable developer carrier that does not cause deterioration such as abrasion of the conductive coating layer on the surface of the developer carrier due to repeated copying or durability and toner contamination, the occurrence of image density reduction or ghost occurs. ,
It is possible to provide a high-quality image for a long time without deterioration of fog.

[Brief description of drawings]

FIG. 1 is a schematic view of a developing device according to an embodiment having a developer carrying member on which a conductive resin coating layer of the present invention is formed.

FIG. 2 is a schematic view of a developing device according to another embodiment of the present invention, in which the developing layer regulating member of the developing device shown in FIG. 1 is different.

FIG. 3 is a schematic view of a developing device according to still another embodiment of the present invention, in which the developing layer regulating member of the developing device shown in FIG. 1 is different.

FIG. 4 is a schematic explanatory view of an image forming apparatus of the present invention.

FIG. 5 is a schematic explanatory view of a specific example of the process cartridge of the present invention.

FIG. 6 is a schematic view of a conventional developing device having a developer carrying member on which a resin coating layer is not formed.

[Explanation of symbols]

 1: Photosensitive drum (electrostatic latent image holder) 2: Magnetic regulation blade 3: Hopper (developer container) 4: Developer (toner) 5: Magnet roller 6: Metal cylindrical tube 7: Conductive resin coating layer 8: Developing sleeve 9: Developing bias power source 10: Stirring blade 11: Elasticity regulating blade 12: Gap 101: Photosensitive drum 103: Developer container 104: One-component developer 105: Multipolar permanent magnet 108: Developing sleeve 109: Bias applied voltage 111: Elasticity regulation blade 113: Contact (roller) transfer means 114: Voltage application means 115: Exposure 116: Erase exposure 118: Heating and pressure roller fixing device 118: Cleaning means 118a: Cleaning blade 119: Contact (roller) charging means 120 : Developing means N1, N2, S1, S2: Magnetic pole A: Rotating developing sleeve B: a photosensitive drum rotation direction D: the developing region P: recording medium

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] January 31, 1996

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0098

[Correction method] Change

[Correction content]

Table 4 Evaluation results (durability concentration, durability fog, durability ghost under high temperature and high humidity)

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Michiko Orihara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Mayoko Maruyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Non-Corporation (72) Inventor Takuya Toyooka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kazuki Saiki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (34)

[Claims] 1. A developer carrier having at least a substrate and a conductive coating layer coating the substrate, wherein a binder resin and a number average particle dispersed in the binder resin are contained in the conductive coating layer. A developer carrying body containing at least conductive spherical particles having a diameter of 0.3 to 30 μm and a true density of 3 g / cm ³ or less. 2. The ratio of major axis / minor axis of the conductive spherical particles is
The developer carrier according to claim 1, wherein the developer carrier is in the range of 1.0 to 1.5. 3. The volume resistance of the conductive spherical particles is 10 ⁶ Ω.
-It is below cm, The developer support body according to claim 1 or 2 characterized by things. 4. The developer carrier according to claim 1, wherein the conductive spherical particles are carbon particles. 5. The developer carrying member according to claim 4, wherein the surface of the carbon particles is plated with a conductive metal, a conductive metal oxide, or both of them. 6. The conductive spherical particles are those in which the surface of the resin particles is treated to be conductive.
The developer carrying member according to 1. 7. The developer carrier according to claim 1, wherein the conductive spherical particles are resin particles in which conductive fine particles are dispersed and contained. 8. The developer carrier according to claim 1, wherein the conductive coating layer further contains lubricating particles in addition to the conductive spherical particles. 9. Lubricating particles are selected from the group of particles consisting of graphite, molybdenum disulfide, boron nitride, mica, graphite fluoride, silver-niobium selenide, calcium chloride-graphite, talc and fatty acid metal salts. 9. The developer carrying member according to claim 8, comprising one or more kinds. 10. The developer carrier according to claim 1, wherein the conductive coating layer further contains conductive fine particles in addition to the conductive spherical particles. 11. The conductive fine particles are carbon black,
A metal oxide, a metal, and at least one selected from the group of particles consisting of an inorganic filler, characterized by comprising 1.
10. The developer carrying member according to item 10. 12. The developer carrier according to claim 1, wherein the surface of the conductive coating layer has a center line average roughness (Ra) of 0.2 to 4.5 μm. 13. A developer container containing a developer, and a thin layer of the developer contained in the developer container is formed on a surface of the developer container and carried, and the developer is conveyed to a developing area. A developing device having a developer carrier for use in the developing device, wherein the developer carrier is the developer carrier according to any one of claims 1 to 12. 14. The developing device according to claim 13, further comprising a developer layer thickness regulating member for forming a thin layer of the developer on the developer carrying member. 15. The developing device according to claim 14, wherein the developer layer thickness regulating member is a magnetic regulation blade. 16. The developing device according to claim 14, wherein the developer layer thickness regulating member is elastically pressed against the developer carrying member via the developer. 17. The developing device according to claim 16, wherein the developer layer thickness regulating member is an elastic regulating member. 18. The developing device according to claim 13, wherein the developer is a magnetic one-component developer containing a magnetic toner. 19. The non-magnetic one-component type developer containing a non-magnetic toner, wherein the developer is a non-magnetic one-component type developer.
The developing device according to 4, 16, or 17. 20. The developer according to claim 13, wherein the developer is a two-component developer containing a toner and a carrier.
7. The developing device according to 7. 21. (i) an electrostatic latent image holding member for holding an electrostatic latent image, and (ii) a developing device for converting the electrostatic latent image into a developed image with a developer in a developing area. An image forming apparatus having the image forming apparatus, wherein the developing apparatus is the developing apparatus according to any one of claims 13 to 20. 22. The image forming apparatus according to claim 21, wherein the electrostatic latent image holding member is a photoconductor for electrophotography. 23. A transfer means for transferring a developed image onto a recording material, further comprising:
The image forming apparatus according to 1 or 22. 24. The image forming apparatus according to claim 21, further comprising fixing means for fixing the developed image transferred onto the recording material. 25. At least: (i) an electrostatic latent image holding member for holding an electrostatic latent image, and (ii) a developing unit for converting the electrostatic latent image into a developed image with a developer in a developing area. In a process cartridge detachably mountable to an image forming apparatus main body integrally provided, a developing means forms a developer container containing a developer and a thin layer of the developer contained in the developer container on a surface thereof. And a developer carrier for carrying the developer to the developing area, wherein the developer carrier is the developer carrier according to any one of claims 1 to 12. Characteristic process cartridge. 26. The process cartridge according to claim 25, wherein the developing means is further provided with a developer layer thickness regulating member for forming a thin layer of the developer. 27. The process cartridge according to claim 26, wherein the developer layer thickness regulating member is a magnetic regulation blade. 28. The process cartridge according to claim 26, wherein the developer layer thickness regulating member is elastically pressed against the developer carrying member via the developer. 29. The process cartridge according to claim 28, wherein the developer layer thickness regulating member is an elastic regulating member. 30. The process cartridge according to claim 25, wherein the developer is a magnetic one-component developer containing a magnetic toner. 31. The non-magnetic one-component type developer containing a non-magnetic toner as claimed in claim 25, 2.
The process cartridge according to 6, 29 or 30. 32. The developer according to claim 25, wherein the developer is a two-component developer containing a toner and a carrier.
9. The process cartridge according to item 9. 33. The process cartridge according to claim 25, wherein the electrostatic latent image holding member is an electrophotographic photosensitive member. 34. In addition to an electrophotographic photosensitive member as an electrostatic latent image holding member and a developing unit, at least one of a cleaning unit and a primary charging unit is integrally formed into a cartridge. 25-33.