JP2003195564A - Electrophotographic device and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic device which excels even in the characteristics in repetitively outputting images, has can supply images of high image quality, high definition and having excellent gradation characteristics for a long period of time while maintaining the developability even in an electrophotographic developing method using a toner (spherical toner) of a small diameter having high circularity as toner and a process cartridge. <P>SOLUTION: The electrophotographic device has a developing means which has a contact electrostatically charging member, one-component toner for dry process having a specific diameter and circularity and an elastic roller, and forms a toner image by developing the electrostatic latent image formed on an electrophotographic photoreceptor by bringing the toner layer formed on the elastic roller by the toners into contact with the surface of the electrophotographic photoreceptor while rotationally moving the elastic roller and the electrophotographic photoreceptor by means of the toner on the above toner layer. The above electrophotographic device has the electrophotographic photoreceptor containing a phthalocyanine compound in a charge generating layer and a polyarylate resin in a charge transfer layer and the process cartridge. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus and a process cartridge applied to a copying machine, a laser printer, a plain paper facsimile, etc., and more specifically to a specific electrophotographic photosensitive member, charging means and developing means. The present invention relates to an electrophotographic apparatus and a process cartridge having the same.

[0002]

2. Description of the Related Art The electrophotographic method is widely used in offices because of its high-speed printability and high image quality. Recently, however, the number of cases of recording graphic images has increased, and even higher image quality, There is a demand for higher definition. In a laser printer, the conventional 240d
The resolution is being further improved from pi to 600 dpi and 1200 dpi. Even in copying machines, digitalization and higher resolution are being promoted.

In addition, full-color electrophotographic devices have been rapidly developed, and high gradation and high image quality are required as well as high image quality and high definition.

In response to these requirements, development and use of precision machining technology and high precision control technology of the device have been proposed and studied.

Further, technological developments such as high image quality by reducing the diameter of toner particles and high image quality and high definition by toner having a high degree of circularity are being actively carried out.

Regarding the reduction of the diameter of the toner and the improvement of the circularity,
In the conventional pulverization method, a toner is obtained by kneading, pulverizing, and classifying a colorant and a binder resin. With a pulverizing toner, finer pulverization, classification means, reduction in diameter by post-treatment such as polishing, and improvement in circularity (sphericalization)
Is being actively researched.

In addition to the pulverized toner, a polymerized toner obtained by dispersing an ethylenically unsaturated monomer containing a colorant in water in the presence of a dispersant and then polymerizing the same is noted.
Energetic research and development. It has been confirmed that the polymerized toner is an effective means for reducing the diameter of the toner and improving the circularity.

As described above, the toner having a small diameter and a high degree of circularity faithfully and accurately develops the electrostatic latent image on the electrophotographic photosensitive member, and exhibits high transferability to improve the image quality of the image. It has a great effect on high definition.

In recent years, a so-called contact one-component developing method in which an elastic roller having semiconductivity or an elastic roller having a dielectric layer on its surface is used as a developing roller to perform development while pressing it against the surface of an electrophotographic photoreceptor. Is proposed. For example, Japan Hardcopy '89 Proceedings 25-28
Page, FUJITSU Sci.Tech.J., 28, 4, pp.473-480 (December 19
92), JP-A-5-188756 and JP-A-5-188756.
Japanese Patent No. 188752 describes a technique relating to one-component contact development.

The contact one-component developing method has an advantage that the edge effect of development can be reduced because the surface of the electrophotographic photosensitive member and the developing electrode are very close to each other, and when the spherical toner as described above is used. There is a possibility of higher image quality and higher definition.

In the contact one-component developing method, it is necessary for the developing roller and the electrophotographic photosensitive member to stably maintain a uniform nip width in their respective axial directions. Therefore, as the developing roller, elasticity of a rubber roller or a sponge roller is used. It is necessary to adopt rollers. Further, the developing roller is strongly pressed against the electrophotographic photosensitive member and in order to develop more toner on the electrophotographic photosensitive member than the surface of the developing roller,
It is necessary to set the peripheral speed of the developing roller higher than that of the electrophotographic photosensitive member. For this reason, the driving torque between the electrophotographic photosensitive member and the developing roller becomes high, causing scratches and abrasion on the surface of the electrophotographic photosensitive member due to long-term use, toner fusion, and deterioration of durability characteristics. There is.

Further, when a spherical toner is used as the toner, the toner layer formed on the developing roller becomes non-uniform, which causes a problem of deterioration of image quality such as reduction of image density and fog. As a method for forming a uniform toner layer, for example, in Japanese Patent Application Laid-Open No. 09-062085, a surface roughness of 10 is used.
There has been proposed a method of forming a uniform toner layer on the developing roller by using a developing roller of μm or less. Further, Japanese Patent Application Laid-Open No. 09-319208 proposes a method of forming a uniform toner layer on the developing roller by defining the average particle diameter of the toner and the unevenness and surface roughness of the surface of the developing roller. However, if the surface roughness is increased, the chances of contact between the toner and the surface of the developing roller are increased, and the amount of toner coating on the developing roller is also increased. As a result, the contact pressure between the developing roller and the electrophotographic photosensitive member is increased. As a result, the driving torque of the developing roller is increased, and there is a problem that the amount of wear of the electrophotographic photosensitive member is increased and toner fusion occurs.

In particular, in the laminated electrophotographic photoreceptor in which the photosensitive layer is laminated in the order of the charge generation layer and the charge transport layer, and the charge transport layer is the surface layer of the electrophotographic photoreceptor, the charge transport layer is the toner and the developing roller. The surface of the electrophotographic photosensitive member is scratched and abraded due to the strong contact and sliding. The scratches and non-uniform wear of the photosensitive layer deteriorate the durability of the electrophotographic photosensitive member and also make the contact of the developing roller with the surface of the electrophotographic photosensitive member non-uniform, causing image defects such as streaks and fog. Although lowering the contact pressure of the developing roller can solve problems such as scratches and abrasion of the electrophotographic photosensitive member at the initial stage, in order to prevent deterioration of developability, the peripheral speed ratio between the developing roller and the electrophotographic photosensitive member is considerably increased. As a result, scratches and abrasion of the electrophotographic photosensitive member are increased in repeated image output, and further problems such as deterioration of toner are likely to occur.

As a method for reducing the amount of wear of the electrophotographic photosensitive member, a method of reducing the amount of wear by increasing the slipperiness of the surface of the electrophotographic photosensitive member by adding silicone resin fine particles and fluororesin particles in the photosensitive layer. JP-A-63-6
It is proposed in Japanese Patent No. 5449. However, even if the slipperiness of the electrophotographic photosensitive member is increased by this method, the photosensitive layer still has low mechanical strength, and inorganic compound particles such as silica, alumina, and titania as toner additives have deep grooves on the surface of the photosensitive layer. Scratches are likely to occur, such as abrasive wear such as digging. Further, the above-mentioned toner additive may be fused to the surface of the photosensitive layer, which may cause toner fusion, which is not a sufficient countermeasure.

Therefore, under the present circumstances, it is difficult to maintain the durability of the electrophotographic photosensitive member while maintaining the developability of the spherical toner in the contact developing method.

On the other hand, it has been found that, with respect to the high gradation of the image, it is known that the linearity of the image density with respect to the gradation improves the reproducibility of the halftone. It is known that this linearity can be obtained as is increased.

Generally, in order to increase the surface charge amount of the electrophotographic photosensitive member, the surface potential of the electrophotographic photosensitive member may be increased or the electrostatic capacity of the electrophotographic photosensitive member may be increased.

At present, as the electrophotographic photosensitive member, an organic electrophotographic photosensitive member is often used for reasons such as production cost and chemical safety. Most of the organic electrophotographic photosensitive members include a charge generation layer,
The surface layer of the electrophotographic photosensitive member is a charge transport layer, which is composed of two layers in which a charge transport layer is laminated in this order. In the case of this layer structure, the capacitance can be increased by decreasing the film thickness of the charge transport layer.

However, increasing the surface potential of the electrophotographic photosensitive member or reducing the film thickness of the charge transport layer causes spots or fog due to dielectric breakdown of the electrophotographic photosensitive member, and particularly charge transport. Reducing the layer thickness not only impairs the durability of the electrophotographic photoreceptor, but also lowers the sensitivity. Actually, the gradation control is maintained by complicated control in the electrophotographic apparatus body. Stays in.

Particularly in a full-color electrophotographic apparatus which is highly demanded for color reproducibility and gradation, a change in sensitivity of the electrophotographic photosensitive member has a great influence on electrostatic latent image formation and further image formation. In the case of using an organic electrophotographic photoreceptor having a surface layer of, it is desirable to minimize the change in the thickness of the charge transport layer, but a thin film as a charge transport layer having sufficient durability has not yet been obtained. is the current situation.

[0021]

As described above, in the contact developing method using a toner having a small diameter and a high circularity (spherical toner), it is possible to maintain the developability of the spherical toner and the durability of the electrophotographic photoreceptor. There is a problem with and there is a need for improvement.

From the viewpoint of high gradation of an image, there is a demand for an organic electrophotographic photosensitive member having a large electrostatic capacity, excellent durability and high sensitivity.

In order to solve the above problems, the present invention provides a toner having a small diameter and a high circularity (spherical toner).
Even in the electrophotographic developing method using, the image can be supplied for a long period of time while maintaining the developability and having excellent characteristics in repeated image output, high image quality, high definition, and excellent gradation. It is an object of the present invention to provide an electrophotographic apparatus and a process cartridge which are to be described below.

[0024]

That is, the present invention is an electrophotographic apparatus having at least an electrophotographic photosensitive member, a charging unit and a developing unit, wherein the charging unit is disposed in contact with the electrophotographic photosensitive member. And a developing member having a toner and an elastic roller, and the toner formed on the elastic roller by the toner while rotating the elastic roller and the electrophotographic photosensitive member relative to each other. A means for forming a toner image by developing an electrostatic latent image formed on the electrophotographic photoreceptor with the toner of the toner layer by bringing the layer into contact with the surface of the electrophotographic photoreceptor. In the electrophotographic apparatus, which is a dry one-component toner having a circle-equivalent number average diameter of 2 to 10 μm, an average circularity of 0.950 to 0.995 and a circularity standard deviation of less than 0.040, Electric A photographic photoreceptor is characterized in that a charge generating layer and a charge transporting layer are laminated in this order on a support, the charge generating layer contains a phthalocyanine compound, and the charge transporting layer contains a polyarylate resin. It is an electrophotographic device.

Further, the present invention is a process cartridge which at least integrally supports an electrophotographic photosensitive member, a charging means and a developing means, and is detachable from the main body of the electrophotographic apparatus, wherein the charging means is the electrophotographic photosensitive material. A charging member disposed in contact with the body, the developing means has a toner and an elastic roller, and the toner is formed on the elastic roller by rotating the elastic roller and the electrophotographic photosensitive member relative to each other. A means for forming a toner image by developing the electrostatic latent image formed on the electrophotographic photosensitive member with the toner of the toner layer by bringing the formed toner layer into contact with the surface of the electrophotographic photosensitive member. The toner has a circle-equivalent number average diameter of 2 to 1
In a process cartridge which is a dry type one-component toner having a particle size of 0 μm, an average circularity of 0.950 to 0.995 and a circularity standard deviation of less than 0.040, the electrophotographic photoreceptor has a charge on a support. A process cartridge comprising a generation layer and a charge transport layer stacked in this order, the charge generation layer containing a phthalocyanine compound, and the charge transport layer containing a polyarylate resin.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The toner used in the electrophotographic apparatus and process cartridge of the present invention is a toner having a small particle size and a high circularity. Specifically, the circle-equivalent number average diameter is 2 to 10 μm, and the average circularity is 0.95.
It is a dry one-component toner having a circularity standard deviation of 0 to 0.995 and less than 0.040.

In the present invention, the circle-equivalent number average diameter of toner, the average circularity, and the circularity standard deviation are, as described later, the circle-equivalent diameter based on the number of toner particles measured by a flow-type particle image measuring device. It is a numerical value in the circularity scattergram.

The circle-equivalent number average diameter of the toner is 2 to 10 μm.
m, preferably 5 to 8 μm by reducing the diameter,
The reproducibility of the outline portion of the image, especially the character image or the line pattern in the development is improved.

However, generally, when the toner particle size is reduced, the abundance ratio of the toner having a minute size is inevitably increased, so that the adhesion of the toner to the surface of the electrophotographic photosensitive member or the developing roller is increased, As a result, problems such as an increase in transfer residual toner and the occurrence of image fog occur.

However, the average circularity of the toner is 0.95.
By setting 0 to 0.995 and the circularity standard deviation of less than 0.040, the transferability of a toner having a small diameter, which is generally difficult, is significantly improved, and the developing ability for a low potential latent image is also improved. Greatly improved.

The circle-equivalent number average diameter, average circularity, and circularity standard deviation of the toner used in the present invention are used as a simple reference for quantitatively expressing the shape of toner particles. These are flow type particle image measuring apparatus FPIA-100
It was measured using a type 0 (manufactured by Toa Medical Electronics Co., Ltd.) and calculated using the following formula.

[0032]

[Outside 3]

Here, the "particle projection area" is the area of the binarized toner particle image, and the "perimeter of the particle projection image".
Is defined as the length of the contour line obtained by connecting the edge points of the toner particle image.

The circularity in the present invention is an index showing the degree of unevenness of the toner particles, and shows 1.000 when the toner particles are completely spherical, and the more complicated the surface shape, the more
The circularity has a small value.

In the present invention, the circle-equivalent number average diameter means the average value of the particle size frequency distribution based on the number of toner particles.

[Outside 4]

The particle size standard deviation SDd is calculated from the following equation, where di is the particle size (center value) at the dividing point i of the particle size distribution and fi is the frequency.

[0037]

[Outside 5]

The average circularity which means the average value of the circularity frequency distribution

[Outside 6]

The circularity standard deviation SDc is calculated from the following equation, where the circularity (center value) at the dividing point i of the particle size distribution is ci and the frequency is f _ci .

[0040]

[Outside 7]

The specific measuring method is as follows.

10 ml of ion-exchanged water from which impure solids and the like had been removed beforehand was prepared in a container, and a surfactant, preferably an alkylbenzene sulfonate, was added as a dispersant into the container, and 0.02 g of a measurement sample was further added. In addition, it is dispersed uniformly. As a means for dispersing, an ultrasonic disperser UH-50 type (manufactured by SMT) equipped with a titanium alloy chip having a diameter of 5 mm as a vibrator was used.
Dispersion treatment for minutes is used to prepare a dispersion liquid for measurement. that time,
The dispersion is appropriately cooled so that the temperature does not exceed 40 ° C.

To measure the shape of the toner particles, the flow type particle image measuring device is used, and the toner particle concentration at the time of measurement is 3,
The concentration of the dispersion liquid is readjusted so as to be 000 to 10,000 particles / μl, and 1,000 or more toner particles are measured.
After the measurement, this data is used to determine the equivalent circle diameter of the toner, the circularity frequency distribution, and the like.

As the wax component used in the toner of the present invention, petroleum wax and its derivatives such as paraffin wax, microcrystalline wax and petroleum cutam, montan wax and its derivative,
Examples include hydrocarbon waxes and their derivatives by Fischer-Tropsch method, polyolefin waxes and their derivatives represented by polyethylene, carnauba wax, candelilla wax, and other natural waxes and their derivatives. Examples of the derivative include oxides, block copolymers with vinyl monomers, and graft modified products. Alcohols such as higher aliphatic alcohols; fatty acids such as stearic acid and palmitic acid or compounds thereof; acid amides, esters, ketones, hydrogenated castor oil and its derivatives, vegetable wax, animal wax, etc. Any material having a temperature of -80 ° C can be used.

Among them, polyolefins, hydrocarbon waxes by the Fischer-Tropsch method, petroleum waxes, higher alcohols or higher esters are more effective in improving the developability and transferability.

The above-mentioned wax component is a binder resin 100.
It is preferable to use 1 to 30 parts by mass with respect to parts by mass.

Examples of the binder resin used in the toner of the present invention include commonly used styrene- (meth) acrylic copolymers, polyester resins, epoxy resins, and styrene-butadiene copolymers. In the method of directly obtaining toner particles by a polymerization method, a monomer for forming them is used.

As the above-mentioned monomer, styrene, o- (m
Styrene-based monomers such as-, p-) methylstyrene and m- (p-) ethylstyrene, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth) acrylic Butyl acid, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate,
(Meth) acrylic acid ester monomers such as 2-ethylhexyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, butadiene, isoprene, cyclohexene,
Ene-based monomers such as (meth) acrylonitrile and acrylic acid amide are preferable.

These monomers can be used alone or in an appropriate mixture so that the theoretical glass transition temperature (Tg) is 40 to 75 ° C. Theoretical glass transition temperature (Tg) is based on Polymer Handbook Second Edition III-P
139-192 (made by John Wiley & Sons)
It is the theoretical glass transition temperature (Tg) described in.

When the theoretical glass transition temperature is lower than 40 ° C., problems easily occur in terms of storage stability and durability stability of the toner, and when it exceeds 75 ° C., the fixing point of the toner tends to increase. In particular, in the case of color toners for forming a full-color image, the color mixing properties at the time of fixing each color toner may be deteriorated, the color reproducibility may be poor, and the transparency of the OHP image may be deteriorated.

The molecular weight of the binder resin is measured by gel permeation chromatography (GPC). In the case of a toner having a so-called core-shell structure in which a substance having a low softening point is encapsulated with an outer shell resin, a specific method for measuring GPC is as follows.

The toner was previously extracted with a Soxhlet extractor with a toluene solvent for 20 hours, and then the toluene was distilled off with a rotary evaporator to obtain an extract.
Further, an organic solvent (such as chloroform) that dissolves the low softening point substance but not the outer shell resin is added to the extract and thoroughly washed, and then the residue is dissolved in tetrahydrofuran (TH
Sample (THF solution) obtained by filtering the solution dissolved in F) with a solvent-resistant membrane filter having a pore size of 0.3 μm.
Is measured using 150C manufactured by Waters. The column configuration is Showa Denko A-801, 802, 803, 80.
4,805,806,807 can be connected and a molecular weight distribution can be measured using the calibration curve of a standard polystyrene resin.

The main peak molecular weight of the binder resin according to the present invention is preferably 5,000 to 1,000,000, and the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is , 2 to 100 are preferable.

The colorants used in the toner used in the present invention include the following yellow colorants, magenta colorants and cyan colorants. Black colorants such as carbon black, magnetic materials or yellow colorants shown below. Agent /
A mixture of magenta colorant / cyan colorant and toned black is used.

As the yellow colorant, condensed azo compounds, isoindolinone compounds, anthraquinone compounds,
Azo metal complexes, methine compounds, allylamide compounds and the like are used. Among these, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 8
3, 93, 94, 95, 109, 110, 111, 12
8,129,147,168,180 is preferable.

As the magenta colorant, a condensed azo compound, a diketopyrrolopyrrole compound, an anthraquinone, a quinacridone compound, a basic dye lake compound, a naphthol compound, a benzimidazolone compound, a thioindigo compound and a perylene compound are used. Among these,
C. I. Pigment Red 2, 3, 5, 6, 7, 23,
48; 2, 48; 3, 48; 4, 57; 1, 81; 1,
144, 146, 166, 169, 177, 184, 1
85, 202, 206, 220, 221, 254 are preferred.

As the cyan colorant, a copper phthalocyanine compound and its derivative, an anthraquinone compound, a basic dye lake compound and the like are used. Among these,
C. I. Pigment Blue 1, 7, 15, 15: 1, 1
5: 2, 15: 3, 15: 4, 60, 62, 66 are preferred.

These colorants can be used alone or as a mixture, and can be used in the form of a solid solution. The colorant is selected in terms of hue, saturation, brightness, weather resistance, OHP transparency, and dispersibility in toner particles. The amount of the colorant added is
It is preferable to use 1 to 20 parts by mass with respect to 100 parts by mass of the resin component.

When a magnetic substance is used as the black colorant, unlike other colorants, the amount is 40 with respect to 100 parts by mass of the resin.
It is preferable to use ˜150 parts by mass.

A known charge control agent can be used in combination with the toner used in the present invention. Particularly, a charge control agent having a high charging speed and capable of stably maintaining a constant charge amount is preferable. Further, when the toner particles are directly polymerized, a charge control agent having no polymerization inhibitory property and having no solubilized product in the aqueous dispersion medium is preferable.

As the negative charge control agent, salicylic acid,
Metal compounds of aromatic carboxylic acids such as naphthoic acid and dicarboxylic acid, polymer type compounds having sulfonic acid or carboxylic acid group in the side chain, boron compounds, urea compounds, silicon compounds, currys arenes, etc. Is mentioned. Examples of the positive charge control agent include a quaternary ammonium salt, a high molecular compound having a side chain of the quaternary ammonium salt, a guanidine compound, and an imidazole compound.

However, the addition of the charge control agent is not essential in the present invention, and when the non-magnetic one-component blade coating developing method is adopted, the triboelectric charging with the blade member or the sleeve member can be positively utilized. .

Addition of inorganic fine particles to the toner used in the present invention is preferable for improving developability, transferability, charge stability, fluidity and durability. As the inorganic fine particles, known ones can be used, but silica, alumina, titania or a double oxide thereof is particularly preferable. Among them, silica is particularly preferable. As silica, it is possible to use both so-called dry process produced by vapor phase oxidation of silicon halide or alkoxide or so-called wet silica called fumed silica, and so-called wet silica produced from alkoxide, water glass and the like. However, dry silica having less silanol groups on the surface and inside the silica fine particles and less production residues such as Na ₂ O and SO ₃ ²⁻ is preferable. Further, in the production process of dry silica, it is possible to obtain composite fine particles of silica and other metal oxide by using other metal halogen compound such as aluminum chloride and titanium chloride together with the silicon halogen compound in the manufacturing process.

[0064] Inorganic fine particles used in the toner used in the present invention has a specific surface area by nitrogen adsorption measured by BET method is ^{30 m} 2 / g or more, but is preferably in the range of from particularly 50 to 400 m ² / g, the toner 100 The silica fine particles are preferably 0.1 to 8 parts by mass, more preferably 0.5 to 5 parts by mass, and even more preferably more than 1.0 and 3.0 parts by mass or less based on the parts by mass.

The inorganic fine particles used in the toner used in the present invention are used for the purpose of hydrophobizing, controlling charging property, and the like.
Silicone varnishes, various modified silicone varnishes, silicone oils, various modified silicone oils, silane coupling agents, silane coupling agents having functional groups, other organosilicon compounds, organotitanium compounds, and other treatment agents. It is preferable to treat them in combination.

The specific surface area was determined according to the BET method by using a specific surface area measuring device Autosorb 1 (manufactured by Yuasa Ionics Co., Ltd.) to adsorb nitrogen gas on the sample surface and calculating the specific surface area using the BET multipoint method.

In order to maintain a high charge amount, achieve a low consumption amount and a high transfer rate, it is more preferable to treat the inorganic fine particles with silicone oil.

Further, other additives such as lubricant particles such as Teflon (registered trademark) particles, zinc stearate particles and polyvinylidene fluoride particles, and cerium oxide particles, within a range that does not have a substantial adverse effect, Abrasives such as silicon carbide particles and strontium titanate particles, fluidity imparting agents such as titanium oxide particles and aluminum oxide particles, anti-caking agents, conductivity imparting such as carbon black particles, zinc oxide particles and tin oxide particles An agent, or organic fine particles and inorganic fine particles having opposite polarities can be used as a developing property improver in a small amount in combination with the toner used in the present invention.

As a method for producing the toner used in the present invention, a resin, a release agent comprising a low softening point substance, a colorant,
After uniformly dispersing the charge control agent and the like using a pressure kneader, an extruder or a media disperser, mechanically or by colliding with a target under a jet stream, after finely pulverizing to a desired toner particle size (if necessary, A step of smoothing and spheronizing the toner particles), and a pulverizing method for sharpening the particle size distribution to obtain a toner through a classification step. In addition, Japanese Patent Publication Sho 56
No. 13945, etc., a method of atomizing a molten mixture into air using a disk or a multi-fluid nozzle to obtain a spherical toner;
No. 9-53856 and Japanese Patent Application Laid-Open No. 59-61842, a method of directly producing a toner using a suspension polymerization method, or an aqueous system in which a monomer is soluble but the obtained polymer is insoluble A toner can be manufactured by employing a dispersion polymerization method in which an organic solvent is used to directly generate a toner or an emulsion polymerization method represented by a soap-free polymerization method in which a toner is directly polymerized in the presence of a water-soluble polar polymerization initiator. it can.

When the toner is manufactured by using the pulverization method, it is difficult to keep the shape of the toner particles within the desired circularity frequency distribution range. In the case of the melt spray method, a certain degree of circularity can be obtained, but the particle size distribution of the obtained toner tends to be wide and it is difficult to control the surface state of the toner. In the case of the dispersion polymerization method, the toner obtained has an extremely sharp particle size distribution, but the selection of materials to be used is narrow and the use of organic solvents complicates the manufacturing equipment from the viewpoint of waste solvent treatment and solvent flammability. It is easy to get complicated. In the case of an emulsion polymerization method represented by soap-free polymerization, it is effective because the particle size distribution of the toner is relatively uniform, but when the emulsifier or polymerization initiator end used is present on the toner particle surface, the environmental characteristics are likely to deteriorate. .

In the present invention, it is important to control the circularity frequency distribution of the toner particles, and it is relatively easy to obtain a fine particle toner having a circle-equivalent number average diameter of 2 to 6 μm under normal pressure or under pressure. Using emulsion polymerization method or suspension polymerization method, the obtained polymer is stylized by using a medium, the method of directly impinging the polymer on a pressure collision plate, or the obtained polymer is added to an aqueous system. Particularly preferred is an agglomeration method in which the particles are frozen or salted out or particles having opposite surface charges are integrated by taking conditions such as pH into consideration, agglomeration and coalescence. Further, a seed polymerization method in which a monomer is further adsorbed on the once-obtained polymer particles and then polymerization is performed using a polymerization initiator can also be suitably used in the present invention.

When the direct polymerization method is used as the toner production method, the circularity frequency distribution and the particle size frequency distribution of the toner particles can be controlled by controlling the kind and addition of a poorly water-soluble inorganic salt or a dispersant acting as a protective colloid. By controlling the method of changing the amount and the mechanical device conditions (for example, the peripheral speed of the rotor, the number of passes, the stirring conditions such as the shape of the stirring blade and the shape of the container), and the solid content concentration in the aqueous solution. Predetermined toner particles can be obtained. Further, as described above, the stirring conditions of the conical dryer used for drying the toner particles,
Predetermined toner particles can also be obtained by adjusting the processing time.

When the toner is dried by heating, the toner particles can be subjected to a spheroidizing treatment. For example, a fluidized bed dryer is used to adjust the stirring conditions of the rotary blades and the treatment time. The shape can be preferred.

In the toner of the present invention, by specifying the physical properties of the wax component as described above, the influence of the coarsening of the toner and the wax component on the spheroidizing treatment of the toner particles as described above is minimized. It is very effective because it can be limited.

When the toner is produced by the direct polymerization method, the polymerization initiator used is, for example, 2,2′-azobis- (2,4-dimethylvaleronitrile) or 2,2′-.
Azo such as azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile A system or diazo type polymerization initiator and a peroxide type polymerization initiator such as benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxy carbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide and lauroyl peroxide are used. The amount of the polymerization initiator used varies depending on the desired degree of polymerization,
Generally, it is used in an amount of 0.5 to 20% by weight based on the polymerizable monomer. The type of the polymerization initiator varies slightly depending on the polymerization method, but it may be used alone or in combination with reference to the 10-hour half-life temperature.

To control the degree of polymerization, known crosslinking agents, chain transfer agents, polymerization inhibitors and the like may be further added and used.

When the suspension polymerization method using a dispersion stabilizer is used as the toner production method, the dispersion stabilizer to be used is
As inorganic compounds, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite , Silica, alumina and the like. As the organic compound, polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose,
Examples thereof include polyacrylic acid and salts thereof, starch and the like. These are used by dispersing them in the aqueous phase. These dispersion stabilizers are used in an amount of 0.2 to 2 with respect to 100 parts by mass of the polymerizable monomer.
It is preferred to use 0 parts by weight.

When an inorganic compound is used as the dispersion stabilizer, a commercially available product may be used as it is, but fine particles of the inorganic compound may be produced in a dispersion medium in order to obtain fine particles. For example, in the case of tricalcium phosphate,
It is advisable to mix the sodium phosphate aqueous solution and the calcium chloride aqueous solution under high-speed stirring.

For fine dispersion of these dispersion stabilizers,
You may use together 0.001-0.1 mass part surfactant. This is for promoting the intended action of the dispersion stabilizer, and examples thereof include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, and potassium stearate. ,
Examples thereof include calcium oleate.

When the direct polymerization method is used as the method for producing the toner used in the present invention, the following production method is possible.

A releasing agent, a colorant, a charge control agent, a polymerization initiator and other additives made of a substance having a low softening point are added to the polymerizable monomer and uniformly dissolved or homogenized by a homogenizer or an ultrasonic disperser. The dispersed monomer composition is dispersed in an aqueous phase containing a dispersion stabilizer by a usual stirrer, homomixer, homogenizer, or the like. Preferably, the stirring speed and stirring time are adjusted so that the droplets of the monomer composition have a desired toner particle size, and granulation is performed. After that, stirring may be performed to the extent that the particle state is maintained and the particles are prevented from settling due to the action of the dispersion stabilizer. The polymerization temperature is preferably 40 ° C. or higher, generally 50 to 90 ° C., and the polymerization is preferably carried out. The temperature may be raised during the latter half of the polymerization reaction, and for the purpose of improving durability in the image forming method of the present invention, the second half of the reaction for removing unreacted polymerizable monomers, by-products, or the like, or After completion of the reaction, part of the aqueous medium may be distilled off from the reaction system. After the reaction,
The produced toner particles are collected by washing and filtration and dried. In the suspension polymerization method, it is usually preferable to use 300 to 3,000 parts by mass of water as a dispersion medium with respect to 100 parts by mass of the monomer composition.

In the electrophotographic apparatus of the present invention, as a developing means, the surface of an elastic roller as a developing roller is coated with the dry one-component toner to form a toner layer,
A means for bringing this into contact with the surface of the electrophotographic photosensitive member is adopted. The toner is preferably a non-magnetic toner, but may be a magnetic toner.

It is important that the toner layer on the elastic roller and the surface of the electrophotographic photosensitive member are in contact with each other. The elastic roller is substantially in contact with the surface of the electrophotographic photosensitive member, which means that the elastic roller is in contact with the electrophotographic photosensitive member when the toner layer is removed from the elastic roller. To do. At this time, in order to obtain a toner image having no edge effect by the electric field acting between the electrophotographic photosensitive member and the elastic roller facing the surface of the electrophotographic photosensitive member through the toner, the elastic roller surface or the surface of the elastic roller is used. It is necessary to have an electric potential in the vicinity and form an electric field between the surface of the electrophotographic photosensitive member and the surface of the elastic roller. Therefore, the elastic rubber of the elastic roller is resistance-controlled in the medium resistance region to form an electric field while preventing conduction with the surface of the electrophotographic photosensitive member, or a thin dielectric layer is provided on the surface layer of the conductive roller. Alternatively, a conductive resin sleeve may be provided on the surface of the electrophotographic photosensitive member facing the surface of the electrophotographic photosensitive member on the conductive roller, or a conductive layer may be provided on the side not facing the electrophotographic photosensitive member with an insulating sleeve. Any configuration is possible.

In the present invention, the elastic roller carrying the toner may rotate in the same direction as the peripheral speed of the electrophotographic photosensitive member, or may rotate in the opposite direction. When the rotations are in the same direction, the peripheral speed of the peripheral speed of the electrophotographic photosensitive member is preferably 100% or more, and 120 to 300%.
Is more preferable, and a peripheral speed of 140 to 250% is more preferable. When the peripheral speed ratio is less than 100%, there may be a problem in image quality such as line breakage. The higher the peripheral speed ratio, the larger the amount of toner supplied to the developing area, and the more frequently toner is desorbed from the latent image.
An image faithful to the latent image is obtained by repeating the scraping off of unnecessary portions and the addition of unnecessary portions.

The electrophotographic apparatus and the process cartridge of the present invention do not use a developing means utilizing a two-component developing method using a magnetic brush formed of a magnetic carrier for toner.

As the cleaning member used in the present invention, a blade, roller, fur brush, magnetic brush or the like can be used. Two or more of these cleaning members may be used in combination.

The electrophotographic photosensitive member used in the present invention has a structure in which a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance are laminated in this order on a support.

The support for use in the electrophotographic photosensitive member of the present invention may be any one having conductivity, such as aluminum,
Metal such as stainless steel, or metal with conductive layer,
Examples thereof include paper and plastic, and examples of the shape include a sheet shape and a cylindrical shape. In particular, when the image input such as LBP is laser light, it is preferable to provide a conductive layer for the purpose of preventing interference fringes due to scattering or covering scratches on the support. This can be formed by dispersing conductive particles such as carbon black and metal particles in a binder resin. The thickness of the conductive layer is 5 to 40 μm, preferably 10
30 μm is suitable.

If necessary, an intermediate layer having an adhesive function and a barrier function can be provided thereon. As the material of the intermediate layer, polyamide, polyvinyl alcohol,
Polyethylene oxide, ethyl cellulose, casein,
Examples thereof include polyurethane and polyether urethane. These are dissolved in a suitable solvent and applied. The thickness of the intermediate layer is 0.05 to 5 μm, preferably 0.3 to 1 μm
Is appropriate.

A charge generation layer is formed on the support or the intermediate layer. The charge generating substance used in the present invention is a phthalocyanine compound.

Examples of the phthalocyanine compound include:
Examples include metal-free phthalocyanine, copper indium chloride, gallium chloride, oxytitanium, zinc, vanadium and the like, or phthalocyanine in which an oxide chloride thereof is coordinated. Among these, halogenated gallium phthalocyanines such as metal-free phthalocyanine, oxytitanium phthalocyanine, hydroxygallium phthalocyanine, and chlorogallium phthalocyanine are preferable in terms of electrophotographic characteristics and image quality.

The charge generating layer may contain a charge generating substance other than phthalocyanine. As the charge generating substance other than phthalocyanine, selenium-tellurium, pyrylium, thiapyrylium dye, anthanthrone, dibenzpyrenequinone, trisazo, cyanine,
Examples include disazo, monoazo, indigo, quinacridone, and asymmetric quinocyanine pigments.

The charge generation layer contains the above charge generation substance in an amount of 0.3 to
Homogenizer with 4 times amount of binder resin and solvent,
Ultrasonic dispersion, ball mill, vibrating ball mill, sand mill, attritor, roll mill, liquid collision type high-speed disperser, etc. are used for good dispersion, and the dispersion is applied and dried to form. The thickness of the charge generation layer is 5 μm or less, preferably 0.1 to 2 μm.

The charge transport layer is formed by applying and drying a coating material in which a charge transport substance and a binder resin are dissolved in a solvent. Examples of the charge transport material used include triarylamine compounds, hydrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, triallylmethane compounds and thiazole compounds. These are combined with 0.5 to 2 times the amount of the binder resin, applied and dried to form the charge transport layer.

The binder resin for the charge transport layer used in the present invention is a polyarylate resin.

Among the polyarylate resins, the polyarylate resin having a repeating structural unit represented by the following formula (1) is preferable.

[0097]

[Outside 8]

In the above formula (1), X ¹ is a carbon atom or a single bond (when it is a single bond, R ⁵ and R ^{6 are not present} ), R ^{1 to} R ^1
4 represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group or an optionally substituted aryl group, R ⁵ ,
R ⁶ represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, or an alkylidene group formed by combining R ⁵ and R ⁶ , and R ^{7 to} R ¹⁰ Represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group, or an optionally substituted aryl group.

The above polyarylate resin may be used alone, or other resins such as polycarbonate resin, polyester resin, polymethacrylic acid ester, polystyrene resin, acrylic resin and polyamide resin,
It may be used as a mixture with an organic photoconductive polymer such as poly-N-vinylcarbazole or polyvinylanthracene.

Specific examples of the repeating structural unit represented by the above formula (1) are shown in Table 1, but the present invention is not limited thereto.

[0101]

[Outside 9]

[0102]

[Outside 10]

[0103]

[Outside 11]

[0104]

[Outside 12]

[0105]

[Outside 13]

Among these, (1-1) and (1-
2), (1-3), (1-10), (1-11), (1
-24) is preferable, and particularly (1-2) and (1-2)
4) is more preferable.

The polyarylate resin used in the present invention is a polymer composed of a single repeating structural unit,
It may be a copolymer composed of two or more kinds of repeating structural units.

In the present invention, the viscosity average molecular weight of polyarylate is preferably 10,000 to 200,000, and particularly preferably 15,000 to 120,000.

The thickness of the charge transport layer of the present invention is preferably 9 μm or more and 18 μm or less.

When the film thickness of the charge transport layer is less than 9 μm, the charging ability of the electrophotographic photosensitive member may be insufficient, and when it is more than 18 μm, the charging stability may be deteriorated and uneven charging may occur.

When the film thickness of the charge transport layer is 18 μm or less, the electrostatic capacity of the electrophotographic photosensitive member is sufficient so that the linearity of the image density with respect to gradation becomes good regardless of the surface potential of the electrophotographic photosensitive member. Can be obtained.

In the electrophotographic apparatus and process cartridge of the present invention, a charging member (contact charging member) arranged in contact with the electrophotographic photosensitive member is used as the charging means, but only DC voltage is applied to the contact charging member. Even when applied to charge the electrophotographic photosensitive member, the discharge current is small, and sufficient durability as the electrophotographic photosensitive member can be obtained even when the thickness of the charge transport layer is 18 μm or less.

Various additives can be added to the surface layer of the electrophotographic photosensitive member used in the present invention. The additives include deterioration inhibitors such as antioxidants and ultraviolet absorbers, and lubricants such as fluorine atom-containing resin fine particles.

The electrophotographic apparatus of the present invention will be described with reference to FIG.

The developing means 60 contains toner 61. The toner is a magnetic toner or a non-magnetic toner.

The surface of the electrophotographic photosensitive member 63 is charged by a charging unit (for example, a charging roller which is a contact charging unit, a charging brush, a charging blade, etc.) 62 to which a voltage is applied by the bias applying unit 62a, and exposure light ( For example, an electrostatic charge image is formed on the electrophotographic photoreceptor 63 by laser light or light from a halogen lamp) 64. Toner coating blade (for example, elastic blade, metal blade, etc.) 64, 1
The electrostatic charge image is developed with the toner 61 contained in the developing means 60 having the developing roller 65 having the elastic layer or the dielectric layer having the medium resistance of 0 ³ to 10 ⁹ Ω · cm. For the development, a regular development method or a reversal development method is used. In the developing section, a DC bias or an alternating bias is applied to the developing roller 65 by the bias applying means 66 as needed. When the transfer material P is conveyed and reaches the transfer portion, a transfer means (eg, a transfer roller, a transfer belt, etc.) to which a voltage is applied by the bias applying means 68.
The toner image on the surface of the electrophotographic photosensitive member 63 is electrostatically transferred onto the transfer material P by being charged while being pressed from the back surface (the side opposite to the electrophotographic photosensitive member 63 side) of the transfer material P by 67. To do. In some cases, the toner image on the electrophotographic photosensitive member 63 is transferred to an intermediate transfer member (not shown) (for example, an intermediate transfer drum, an intermediate transfer belt, etc.), and the toner image is transferred from the intermediate transfer member to the transfer material P. Good.

The toner image on the transfer material P separated from the electrophotographic photosensitive member 63 is fixed on the transfer material P by a heating / pressurizing means (for example, a heating / pressurizing roller fixing means) 69. The toner remaining on the electrophotographic photosensitive member 63 after the transfer process is removed from the surface of the electrophotographic photosensitive member 63 by a cleaning unit (for example, a cleaning blade, a cleaning roller, a cleaning brush) 70, if necessary. For the electrophotographic photosensitive member 63 after cleaning, the process starting from the charging process by the charging unit 62 is repeated.

Further, FIG. 3 shows a schematic sectional view of one specific example of the process cartridge taken out from the main body of the electrophotographic apparatus. The process cartridge is a cartridge in which the developing means and the electrostatic image holder are at least integrally formed, and the process cartridge is formed so as to be attachable to and detachable from the main body of the electrophotographic apparatus (for example, a copying machine, a laser beam printer, etc.). In the process cartridge shown in FIG. 3, a developing roller (elastic roller) 19 is attached to the developing means 15.
Is pressed against the electrophotographic photosensitive member 10 so as to form a nip portion, and the developing roller 19 is provided with the coating blade 8 and the coating roller 12 in pressure contact with each other. Further, a charging roller 11 and a cleaning blade 13 are provided in pressure contact with the electrophotographic photosensitive member 10.

In the image forming method of the present invention, the electrophotographic photosensitive member and the toner carrying member are in contact with each other via the toner, and either the electrophotographic photosensitive member or the toner carrying member is an elastic body or a flexible belt or It is preferably a tube. For example, a drum-shaped electrophotographic photosensitive member
There are combinations of a developing elastic roller, a drum-shaped electrophotographic photosensitive member-developing flexible tube, and a belt-shaped electrophotographic photosensitive member-developing elastic roller.

[0120]

EXAMPLES The present invention will be described below with reference to examples. However, the present invention is not limited to this. In addition, "part" in an Example shows a mass part.

[Toner Production Example] 650 g of ion-exchanged water and 0.1 mol / l of ion exchange water were placed in a 2-l four-necked flask equipped with a high-speed stirring device TK homomixer (made by Tokushu Kika Kogyo Co., Ltd.).
-Na ₃ PO ₄ aqueous solution 500g was charged, the rotational speed 1
It was adjusted to 2,000 rpm and heated to 70 ° C. 70 parts of a 1.0 mol / l-CaCl ₂ aqueous solution was gradually added thereto to prepare an aqueous dispersion medium containing a minute sparingly water-soluble dispersion stabilizer Ca ₃ (PO ₄ ) ₂ . On the other hand, as a dispersoid, styrene 78 parts 2-ethylhexyl acrylate 22 parts divinylbenzene 0.2 parts carbon black (particle size = 45 nm) 5 parts polycarbonate resin (peak molecular weight = 7,000) 5 parts di-tert-butylsalicylic acid Chromium compound 2 parts Ester wax (mp = 62 ° C.) A mixture of 10 parts was dispersed for 3 hours using an attritor (manufactured by Mitsui Kinzoku Co., Ltd.), and then 2,2′-azobis (2,4-dimethylvaleronitrile). 10 parts was added to prepare a polymerizable monomer composition.

Then, the polymerizable monomer is added to the aqueous dispersion medium.
The body composition is added, and the internal temperature is 70 ° C. _TwoFast in the atmosphere
While maintaining the rotation speed of the stirrer at 12,000 rpm, 1
The polymerizable monomer composition was granulated by stirring for 5 minutes. That
After that, change the stirrer to a propeller stirring blade and stir at 50 rpm.
While maintaining the same temperature for 5 hours, raise the temperature to 80 ° C.
The temperature was maintained for 10 hours to complete the polymerization.

After the completion of the polymerization, the suspension was cooled, and then dilute hydrochloric acid was added to remove the dispersion stabilizer. After repeating washing with water several times, using a fluidized bed dryer (manufactured by Okawara Seisakusho Co., Ltd.), the toner particles were spheroidized and dried for 10 hours while stirring in hot air to obtain polymer particles (A). It was

The polymer particles (A) had an equivalent circle number average diameter of 4.1 μm, an average circularity of 0.990 in the circularity frequency distribution, and a circularity standard deviation of 0.030.
According to the molecular weight distribution, the peak molecular weight is 15,000, M
The w / Mn was 18.

100 parts of the polymer particles (A) and 2 parts of the hydrophobic oil-treated silica fine particles (BET; 200 m ² / g) were dry-mixed with a Henschel mixer (manufactured by Mitsui Kinzoku Co., Ltd.) to prepare the toner of the present invention. .

[Production Example 1 of electrophotographic photosensitive member] Diameter 30 m
An aluminum cylinder having a length of 26 m and a length of 260.5 mm was used as a support, and a coating material composed of the following materials was applied onto the support by dip coating and heat-cured at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 15 μm. Was formed.

Conductive pigment: SnO ₂ coated barium sulfate 10 parts Resistance adjusting pigment: titanium oxide 2 parts Binder resin: phenol resin 6 parts Leveling material: silicone oil 0.001 part Solvent: methanol, methoxypropanol 0.2 /0.8 20 parts Next, on this conductive layer, N-methoxymethylated nylon 3
Parts and 3 parts of copolymerized nylon are mixed with 65 parts of methanol, n-
A solution of 30 parts of butanol dissolved in a mixed solvent was applied by a dipping method to form an intermediate layer having a film thickness of 0.5 μm.

Next, the diffraction angle 2 in X-ray diffraction of CuKα
θ ± 0.2 ° is 9.0 °, 14.2 °, 23.9 °, 2
4 parts of TiOPc having a strong peak at 7.1 °, 2 parts of polyvinyl butyral (trade name: S-REC BM2, manufactured by Sekisui Chemical Co., Ltd.) and 60 parts of cyclohexanone were dispersed in a sand mill using glass beads having a diameter of 1 mm for 4 hours, and then ethyl. A charge generation layer dispersion liquid was prepared by adding 100 parts of acetate. This is applied by the dipping method, and the film thickness is 0.3.
A charge generation layer of μm was formed.

Next, in order to form the charge transport layer, a coating material for the charge transport layer was prepared.

A polyarylate resin (Mw = 101,00) having a repeating structural unit represented by the above formula (1-2).
0) 10 parts and 8 parts of an amine compound having a structure represented by the following formula

[Outside 14]

1 part of an amine compound having a structure represented by the following formula

[Outside 15]

Was dissolved in a mixed solvent of 50 parts of monochlorobenzene and 50 parts of dichloromethane.

This coating material was applied by a dipping method, and the temperature was 120 ° C. for 2 hours.
After drying for an hour, a charge transport layer having a thickness of 15 μm was formed to prepare an electrophotographic photosensitive member (1).

[Production Example 2 of Electrophotographic Photosensitive Member] In Production Example 1 of electrophotographic photosensitive member, the film thickness of the charge transport layer was 18 μm.
An electrophotographic photosensitive member (2) was prepared in the same manner as in Production Example 1 of electrophotographic photosensitive member except for the above.

[Production Example 3 of Electrophotographic Photosensitive Member] Electrophotographic photosensitive member produced in the same manner as in Production Example 1 of electrophotographic photosensitive member except that the thickness of the charge transport layer was changed to 12 μm. (3) was created. [Production Example 4 of Electrophotographic Photoreceptor] Production Example 1 of Electrophotographic Photoreceptor
In the same manner as in Production Example 1 of the electrophotographic photosensitive member except that the charge generation layer was changed as follows, in the electrophotographic photosensitive member (4)
It was created.

Bragg angle 2 in X-ray diffraction of CuKα
θ ± 0.2 ° is 7.5 °, 9.9 °, 12.5 °, 1
2.5 parts of hydroxygallium phthalocyanine crystals having strong peaks at 6.3 °, 18.6 °, 25.1 °, 28.3 °, 1 part of polyvinyl butyral (trade name: S-REC BM2, manufactured by Sekisui Chemical) and cyclohexanone 60
After being dispersed for 3 hours with a sand mill using glass beads having a diameter of 1 mm, 50 parts of cyclohexanone and 130 parts of ethyl acetate were added and diluted to prepare a coating material for the charge generation layer. This charge generation layer coating material was applied onto the undercoat layer by dip coating and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.

[Production Example 5 of Electrophotographic Photoreceptor] In Production Example 2 of electrophotographic photoreceptor, a polyarylate resin having a repeating structural unit represented by the above formula (1-2) as a binder resin for the charge transport layer. (Mw = 101,000) 10
In place of parts, polyarylate resin (copolymerization ratio = 1: 1, Mw = 120,000) consisting of a copolymer of repeating structural units represented by the above formulas (1-2) and (1-24) 10
An electrophotographic photosensitive member (5) was prepared in the same manner as in the electrophotographic photosensitive member Production Example 2 except that the parts were used.

[Comparative Production Example 1 of Electrophotographic Photoreceptor] An electrophotographic photoreceptor (6) was prepared in the same manner as in Production Example 1 except that the thickness of the charge transport layer was changed to 25 μm.

[Comparative Production Example 2 of Electrophotographic Photoreceptor] An electrophotographic photoreceptor (7) was prepared in the same manner as in Production Example 1 except that the thickness of the charge transport layer was changed to 10 μm.

[Comparative Production Example 3 of Electrophotographic Photoreceptor] A support, a conductive layer, an undercoat layer and a charge generation layer were formed in the same manner as in Electrophotographic Photoreceptor Production Example 1.

Instead of the polyarylate resin used in Production Example 1 of electrophotographic photosensitive member, the weight average molecular weight Mn was 100,0.
A charge transport layer coating composition prepared by dissolving 25 parts of Z-type polycarbonate resin No. 00 of 50 in a mixed solvent of 50 parts of monochlorobenzene and 20 parts of dichloromethane and having a film thickness of 18 μm is formed on the charge generation layer. An electrophotographic photosensitive member (8) was obtained.

[Comparative Production Example 4 of Electrophotographic Photoreceptor] The electrophotographic photoreceptor (9) was prepared in the same manner as in Production Example 1 of electrophotographic photoreceptor except that the compound having the following structural formula was used as the charge-generating substance. Was produced.

[0143]

[Outside 16]

(Embodiment 1) As an electrophotographic apparatus, an LBP manufactured by Hewlett Packard having the structure shown in FIG.
"Laserjet 4000" (Process speed 9
A modified machine of 4.2 mm / s) was used.

The outline of the apparatus will be described with reference to FIG. This apparatus uses a charging roller 21 to uniformly charge an electrophotographic photosensitive member (electrophotographic photosensitive drum having a diameter of 30 mm) 26. After charging, an electrostatic latent image is formed by exposing the image portion with a laser beam, and a visible image (toner image) is formed with toner, and then the toner image is transferred onto a transfer material 28 by a transfer roller 27 to which a voltage is applied. To do.

The modification was carried out as follows.

Charging of the electrophotographic photosensitive member was carried out by constant voltage control using only a DC power supply as a high voltage power supply.

The developing member in the process cartridge was modified as follows. A medium resistance rubber roller (diameter 16 mm; core bar 6 mm) made of urethane foam and having an electric resistance value of 10 ⁵ Ω · cm is used as the developing roller 24 instead of the aluminum sleeve containing the magnet as the toner supply body, and the electrophotographic photosensitive member is used. 26 was contacted with the nip so that the nip was about 3 mm. The rotational peripheral speed of the developing roller was in the same direction at the contact portion with the electrophotographic photosensitive member, and was driven so as to be 150% of the rotational peripheral speed of the electrophotographic photosensitive member. The peripheral speed of the developing roller is 141.3 mm / s, and the peripheral speed of the surface of the electrophotographic photosensitive member is 94.2 mm / s.
Met.

As a means for applying toner to the developing roller 24, an applying roller 25 is provided inside the developing container 22,
It was brought into contact with the developing roller 24. The toner was applied onto the developing roller 24 by rotating in the direction opposite to the developing roller 24 at the contact portion. Further, a stainless steel blade 23 coated with resin was attached for controlling the toner coating layer on the developing roller 24. As the cleaning member, the cleaning blade 29 was used in the cleaner container 30.

The electrophotographic photoconductor (1) of Production Example 1 was used as the electrophotographic photoconductor, the toner of the above Production Example was used as the toner, and the process conditions were set so as to satisfy the following conditions.

Electrophotographic photoconductor dark area potential −650V Electrophotographic photoconductor bright area potential −150V Development bias −480V (DC component only) This electrophotographic apparatus is installed in an environment of temperature and humidity 23 ° C./60%, and toner is replenished. While maintaining 4% area ratio on A4 size paper
A continuous image output test was performed on 10,000 sheets with a printed character pattern for evaluation.

The images were evaluated before and after the durability of the electrophotographic photosensitive member by a halftone test chart in which one dot was printed in a Keima pattern on the entire print surface and a solid black image. The evaluation results are shown in Table 2.

Further, the abrasion loss of the photoconductor was measured after the continuous image output test of 10,000 sheets. The results are shown in Table 2.

(Examples 2 to 5 and Comparative Examples 1 to 4) Electrophotographic photosensitive members (2) to
Evaluations were made in the same manner as in Example 1 except that (9) was used.
The evaluation results are shown in Table 2.

The evaluation criteria of the image evaluation items in the above-mentioned examples and comparative examples are as follows.

<1> Image Density The average image density of 10 arbitrary points on the solid black image printed out was evaluated. The image density was measured by using a Macbeth reflection densitometer (manufactured by Macbeth Co., Ltd.) to measure the relative density with respect to an unused print paper having a reflection density of 0.00, and the rank was set as follows.

A: Image density 1.35 or more B: Image density 1.25 or more, less than 1.35 C: Image density 1.00 or more, less than 1.25 D: Image density less than 1.00 <2> Fog print The fog density of the solid white image that was output was evaluated. The fog density (%) was calculated from the difference between the whiteness of the printout image and the whiteness of the unused print paper using a reflectometer (manufactured by Tokyo Denshoku Co., Ltd.).

A: Less than 2.0% B: 2.0% or more, less than 3.0% C: 3.0% or more, less than 5.0% D: 5.0% or more <3> Dot reproducibility print A halftone image in which 1 dot (60 μm) of an isolated dot was printed in a Keima pattern on the entire surface was printed out and the dot reproducibility was evaluated.

[0159] A: Dot loss 2 or less / 100 B: 3 to 5 dot defects / 100 dots C: Dot loss 6 to 10/100 D: Dot loss 11 or more / 100

[Outside 17]

As is clear from Table 2, the electrophotographic apparatus of the examples of the present invention maintained the developability of the toner in the contact developing method using spherical toner, while maintaining the durability and high sensitivity of the electrophotographic photosensitive member. It is possible to maintain the image quality, and it is possible to stably provide a high-quality, high-definition and high-gradation image for a long period of time.

[0161]

According to the present invention, in an electrophotographic apparatus using a toner having a small diameter and a high circularity as the toner, mechanical development of the electrophotographic photosensitive member during repeated image output while maintaining toner developability. It has become possible to provide an electrophotographic device that suppresses, has high image quality, high stability, and high gradation.

[Brief description of drawings]

FIG. 1 shows a schematic configuration diagram of an electrophotographic apparatus used in Examples and Comparative Examples.

FIG. 2 shows a schematic sectional view of one specific example of the electrophotographic apparatus of the present invention.

FIG. 3 is a schematic cross-sectional view of one specific example of the process cartridge of the present invention taken out from the electrophotographic apparatus main body.

[Explanation of symbols]

21 Charging roller 22 developer container 23 Stainless Steel Blade 24 Developing roller 25 Application roller 26 Electrophotographic Photoreceptor 27 Transfer roller 28 Transfer material 29 Cleaning blade 30 cleaner containers 60 developing means 61 toner 62 charging means 62a Bias applying means 63 Electrophotographic photoreceptor 64 exposure light 64 65 developing roller 66 bias applying means 67 transfer means 68 bias applying means 69 heating and pressurizing means 70 Cleaning means P transfer material 8 Coating blade 10 Electrophotographic photoreceptor 10 11 charging roller 12 Application roller 13 Cleaning blade 15 Developing means 19 Development roller (elastic roller) T toner

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/02 101 G03G 15/08 501D 15/08 501 9/08 384 F term (reference) 2H005 AA15 AB06 EA05 2H068 AA13 AA19 AA37 BA39 BB27 FA03 FA27 2H077 AD06 AD35 AD36 BA03 EA13 EA14 EA15 FA13 FA22 GA17 2H200 FA16 GA23 GA46 GA52 GA56 GA57 GA59 HA03 HB12 HB22 HB48 JB13 NA02

Claims (12)

[Claims] 1. An electrophotographic apparatus having at least an electrophotographic photosensitive member, a charging unit and a developing unit, wherein the charging unit has a charging member arranged in contact with the electrophotographic photosensitive member, and the developing unit. Has a toner and an elastic roller, and while rotating the elastic roller and the electrophotographic photosensitive member relative to each other, the toner layer formed on the elastic roller by the toner is formed on the surface of the electrophotographic photosensitive member. A means for developing an electrostatic latent image formed on the electrophotographic photosensitive member by contact with the toner of the toner layer to form a toner image, the toner having a circle-equivalent number average diameter of 2 to 10 μm. And
In an electrophotographic apparatus, which is a dry one-component toner having an average circularity of 0.950 to 0.995 and a circularity standard deviation of less than 0.040, the electrophotographic photoreceptor has a charge generation layer on a support, An electrophotographic apparatus comprising a charge transport layer laminated in this order, the charge generation layer containing a phthalocyanine compound, and the charge transport layer containing a polyarylate resin. 2. The electrophotographic apparatus according to claim 1, wherein the charging unit is a unit that charges the electrophotographic photosensitive member only with a DC voltage. 3. The electrophotographic apparatus according to claim 1, wherein the toner is a toner manufactured by a suspension polymerization method. 4. The electrophotographic apparatus according to claim 1, wherein the charge transport layer of the electrophotographic photosensitive member has a film thickness of 9 to 18 μm or less. 5. The electrophotographic apparatus according to claim 1, wherein the phthalocyanine compound contained in the charge generation layer of the electrophotographic photosensitive member is oxytitanium phthalocyanine or hydroxygallium phthalocyanine. 6. The polyarylate resin contained in the charge transport layer of the electrophotographic photosensitive member is a polyarylate resin having a repeating structural unit represented by the following formula (1). Electrophotographic device. [Outer 1] (X ¹ is a carbon atom or a single bond (when it is a single bond,
R ⁵ and R ^{6 are not present} ), R ^{1 to} R ⁴ represent a hydrogen atom, a halogen atom, an optionally substituted alkyl group or an optionally substituted aryl group, and R ⁵ and R ⁶ are a hydrogen atom, a halogen atom, An optionally substituted alkyl group, an optionally substituted aryl group, or an alkylidene group formed by combining R ⁵ and R ⁶ , wherein R ^{7 to} R ¹⁰ are each a hydrogen atom, a halogen atom, or a substituted Represents an optionally substituted alkyl group or an optionally substituted aryl group. ) 7. A process cartridge which at least integrally supports an electrophotographic photosensitive member, a charging unit and a developing unit, and is detachable from an electrophotographic apparatus main body, wherein the charging unit is arranged in contact with the electrophotographic photosensitive member. The developing member has a toner and an elastic roller, while rotating the elastic roller and the electrophotographic photosensitive member with respect to each other,
The electrostatic latent image formed on the electrophotographic photosensitive member is developed with the toner of the toner layer by bringing the toner layer formed on the elastic roller by the toner into contact with the surface of the electrophotographic photosensitive member. And a toner having a circle-equivalent number average diameter of 2 to 10 μm,
In a process cartridge which is a dry one-component toner having an average circularity of 0.950 to 0.995 and a circularity standard deviation of less than 0.040, the electrophotographic photoreceptor has a charge generation layer and a charge on a support. A process cartridge comprising a transport layer laminated in this order, the charge generating layer containing a phthalocyanine compound, and the charge transport layer containing a polyarylate resin. 8. The process cartridge according to claim 7, wherein the charging unit is a unit that charges the electrophotographic photosensitive member only with a DC voltage. 9. The process cartridge according to claim 7, wherein the toner is a toner manufactured by a suspension polymerization method. 10. The process cartridge according to claim 7, wherein the thickness of the charge transport layer of the electrophotographic photosensitive member is 9 to 18 μm or less. 11. The process cartridge according to claim 7, wherein the phthalocyanine compound contained in the charge generation layer of the electrophotographic photosensitive member is oxytitanium phthalocyanine or hydroxygallium phthalocyanine. 12. The polyarylate resin contained in the charge transport layer of the electrophotographic photosensitive member is a polyarylate resin having a repeating structural unit represented by the following formula (1). Process cartridge. [Outside 2] (X ¹ is a carbon atom or a single bond (when it is a single bond,
R ⁵ and R ^{6 are not present} ), R ^{1 to} R ⁴ represent a hydrogen atom, a halogen atom, an optionally substituted alkyl group or an optionally substituted aryl group, and R ⁵ and R ⁶ are a hydrogen atom, a halogen atom, An optionally substituted alkyl group, an optionally substituted aryl group, or an alkylidene group formed by combining R ⁵ and R ⁶ , wherein R ^{7 to} R ¹⁰ are each a hydrogen atom, a halogen atom, or a substituted Represents an optionally substituted alkyl group or an optionally substituted aryl group. )