JP3937927B2 - Electrophotographic apparatus and process cartridge - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an electrophotographic apparatus such as a copying machine, a laser printer, and a plain paper facsimile.And process cartridgeMore specifically, an electrophotographic apparatus having excellent image quality and durability stabilityas well as Process cartridgeAbout.
[0002]
[Prior art]
  In recent years, with the rapid development of the information industry, high-quality image recording is desired for industrial or office use. In response to these demands, various methods such as an electrophotographic method, a thermal transfer method, and an ink jet method have been proposed and put into practical use. Among them, the electrophotographic method is frequently used in offices because of its high-speed printability and merits of high image quality. Recently, there are many cases of recording graphic images, and there is a demand for higher image quality and higher definition. It has been. In response to these market demands, the resolution of laser printers has been increased from 240 dpi to 600 and 1200 dpi, and higher image quality has been achieved in electrophotographic devices, such as digitalization and higher resolution in copying machines. High-definition is being promoted.
[0003]
  In response to these movements, development of precision processing technology and development and use of high-precision control technology have been proposed and studied from the device development side, but from the toner development side, the small diameter of the toner size has been proposed. The development of high image quality by high-quality, high-quality and high-definition technology by toner with high circularity is being actively carried out. In order to reduce the diameter and improve the circularity of these toners, the conventional colorant and binder resin are kneaded, pulverized, and classified to obtain toner. Researches have been actively made to reduce the diameter, spheroidization, etc. On the other hand, a polymerized toner obtained by polymerizing an ethylenically unsaturated monomer containing a colorant after being dispersed in water in the presence of a dispersant. Attention has been focused on and research and development has been carried out vigorously, and it has been confirmed that the polymerized toner is an effective means for reducing the diameter of the toner and improving the circularity. This small diameter and high circularity toner develops the electrostatic latent image on the photoreceptor faithfully and accurately, and exhibits high transferability, which is great for high image quality and high definition. Bring effect.
[0004]
  In recent years, a so-called contact one-component development method has been proposed in which development is performed while pressing against the surface of a photoreceptor using a semiconductive or elastic roller having a dielectric layer on the surface as a developing roller. For example, Japan Hardcopy '89, 25-28, FUJITSU Sci. Tech. J. et al. , 28, 4, pp. 473-480 (December 1992), Japanese Patent Application Laid-Open No. 5-188756 and Japanese Patent Application Laid-Open No. 5-188752 describe techniques relating to one-component contact development.
[0005]
  In the contact one-component development method, since the surface of the photoreceptor and the development electrode are very close to each other, there is an advantage that the edge effect of the development can be reduced. There is a possibility of higher image quality and higher definition.
[0006]
  In the contact one-component development method, in order to stably maintain a uniform nip width in the axial direction between the developing roller and the photosensitive member, an elastic roller such as a rubber roller or a sponge roller is in contact with the developing roller, and the developing roller In this case, it is necessary to set the peripheral speed of the developing roller faster than the peripheral speed of the photoconductor in order to develop a larger amount of toner on the photoconductor than the surface of the developing roller. For this reason, the driving torque between the photosensitive member and the developing roller is increased, causing a problem that the surface of the photosensitive member is scratched or worn and the toner is fused due to long-term use, and the durability characteristics deteriorate.
[0007]
  Further, when spherical toner is used as the toner, the toner layer formed on the developing roller becomes non-uniform, and there is a problem of image quality deterioration such as image density reduction and fogging. For example, Japanese Patent Laid-Open No. 9-62085 Is a method of forming a uniform toner layer on the developing roller by using a developing roller having a surface roughness of 10 μm or less. Japanese Patent Application Laid-Open No. 9-319208 discloses an average toner particle size and irregularities on the developing roller surface, Although a method for defining the surface roughness and forming a uniform toner layer on the developing roller is disclosed, increasing the surface roughness increases the chance of contact between the toner and the developing roller surface. The toner coat amount also increases, resulting in an increase in the contact pressure between the developing roller and the photosensitive drum, which increases the driving torque of the developing roller, which also increases the amount of wear on the photosensitive member and the occurrence of toner fusion. Cormorant problem arises.
[0008]
  In particular, in an organic laminated type photoreceptor composed of a photosensitive layer comprising a charge generation layer and a charge transport layer, the charge transport layer strongly contacts and slides against the toner and the developing roller, so that the surface of the photoreceptor is scratched and worn. To do. The scratches and uneven wear of the photosensitive layer decrease the durability of the photosensitive member and make the contact between the developing roller and the surface of the photosensitive member uneven, thereby causing image defects such as streaks and fogging. Although lowering the contact pressure of the developing roller can solve problems such as scratches and abrasion of the initial photoconductor, the peripheral speed ratio between the developing roller and the photoconductor needs to be considerably increased in order to prevent deterioration in developability. In repeated image output, scratches and abrasion of the photoconductor increase, and problems such as toner deterioration tend to occur.
[0009]
  JP-A 63-65449 discloses a method for reducing the wear amount of a photoconductor by increasing the slipperiness of the surface of the photoconductor by adding silicone resin fine particles or fluororesin particles in the photosensitive layer. However, even if the slipperiness of the photoreceptor is increased by these methods, the photosensitive layer still has low mechanical strength, and inorganic compound powders such as silica, alumina, and titania, which are toner additives, dig deep grooves on the surface of the photosensitive layer. Scratches are likely to occur due to such abrasive wear, and the toner additive is fused to the surface of the photosensitive layer, which may cause toner fusion, which is not a sufficient countermeasure.
[0010]
  On the other hand, as described above, toner with a small diameter and high circularity faithfully and accurately develops the electrostatic latent image on the photoreceptor, and exhibits high transferability to improve image quality and resolution. Although it has an enormous effect, it has a disadvantage that cleaning properties are low, and problems such as poor cleaning frequently occur during a printing test in a copying machine or a printer.
[0011]
  In electrophotographic apparatuses such as copying machines and printers, after a toner image formed on the surface of a photoconductor is transferred to a transfer material, untransferred toner remains on the surface of the photoconductor, and the residual toner is a brush, a magnetic brush, or a blade. Or the like from the surface of the photoreceptor. For brush cleaning, polyester and acrylic fibers are used, and the shape of loops and straight hairs, the hardness and thickness of the fibers, etc. are changed for optimization. However, cleaning with a brush alone cannot remove the fine powder toner, and cannot pass through the fibers sufficiently. The same applies to the magnetic brush, and electrostatic removal is also attempted by applying an electric field, but toner scattering occurs and is not sufficient. Therefore, at present, blade cleaning using an elastic blade is mainly used from the standpoint of removal of residual toner, cost, miniaturization, and the like. There are many reports regarding improvements in blade cleaning, which are disclosed in patent publications. For example, Japanese Patent Laid-Open No. 5-35156 discloses examination results of physical property values such as hardness, elastic modulus and elongation of a urethane rubber blade and cleaning characteristics.
[0012]
  In this way, the blade cleaning has high cleaning performance compared with other methods. However, when the above-mentioned toner having a small diameter and high circularity is cleaned, it is sufficient in any environment where a copying machine or a printer is used. It is difficult to exhibit the cleaning performance, and cleaning failure tends to occur particularly in an environment of high temperature and high humidity and low temperature and low humidity. In particular, when a toner having a small diameter and a high degree of circularity is used, a cleaning defect in which the toner slips between the cleaning blade and the surface of the photosensitive member is likely to occur at the initial stage. In addition, streaky cleaning defects are likely to occur due to uneven contact between the cleaning blade and the surface of the photoreceptor due to uneven wear. Increasing the contact pressure of the cleaning blade to the photoreceptor surface in order to improve the initial slipping-out cleaning failure improves the initial cleaning performance, but the photoreceptor surface is scratched and unevenly worn during repeated image output. As a result, the cleaning performance tends to be deteriorated. As a result, if the contact pressure of the cleaning blade to the surface of the photosensitive member is too high, the blade is likely to be turned over.
[0013]
  Therefore, it is difficult to maintain the toner cleaning property and the durability of the photosensitive member while maintaining the developing property of the spherical toner in the contact developing method.
[0014]
[Problems to be solved by the invention]
  As described above, the contact development method using a toner having a small diameter and a high degree of circularity has problems in maintaining the developability of the spherical toner and in achieving compatibility between the toner cleaning property and the durability of the photoreceptor, particularly the organic photoreceptor. Was demanded.
[0015]
  An object of the present invention is to solve such a problem, and in an electrophotographic developing method using a toner having a small diameter and a high circularity as a toner, while maintaining developability, it is excellent in characteristics at the time of repeated image output and high. An object of the present invention is to provide an electrophotographic apparatus and a process cartridge that can supply an image quality and a high-definition image over a long period of time.
[0016]
[Means for Solving the Problems]
  In accordance with the present invention,With electrophotographic photoreceptor, Charging means, developing means, transfer means, fixing means, and cleaning meansWhenTheat leastIn an electrophotographic apparatus having
  TheThe developing means forms a toner layer on the elastic roller, and the elastic rollerTheThe electrostatic latent image formed on the electrophotographic photosensitive member is developed with the toner of the toner layer by bringing the toner layer into contact with the surface of the electrophotographic photosensitive member while rotating the electrophotographic photosensitive member relative to each other. And a means for forming a toner image,
  The toner is measured by a flow type particle image measuring device. The number-of-circle-based equivalent diameter of the toner-the circularity scattergram has a circle-equivalent number average diameter of 2.−10 μm and average circularity of 0.950−Dry type with 0.995 and circularity standard deviation less than 0.040oneComponent toner,
  The electricityThe photoconductor is composed of a charge generation layer and a charge transport layer in this order on a conductive support.An electrophotographic photosensitive member, wherein the charge transport layer binder resin is a polyarylate resin,Universal hardness HU at an indentation depth of 1 μm from the surface of the charge transport layer is248N / mm²more than254N / mm²The elastic deformation rate is37%more than43.2% or less,And the universal hardness HU at the indentation depth of 5 μm from the surface is290N / mm²more than305 N / mm ² Less thanThe elastic deformation rate is33.9%more than38.2% or lessAn electrophotographic apparatus and a process cartridge are provided.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described in detail.
[0018]
  The toner used in the electrophotographic apparatus of the present invention is a toner having a small particle diameter and high circularity. The circle equivalent number average diameter of toner is 2−10 μm, preferably 5−By reducing the diameter to 8 μm, the reproducibility in the development of the contour portion of the image, particularly the character image or the line pattern is improved. However, generally, when the toner particle diameter is reduced, the ratio of the toner having a small diameter is inevitably increased, so that the adhesion force of the toner to the surface of the photosensitive member and the developing roller is increased. This causes problems such as an increase and occurrence of image fogging.
[0019]
  However, in the present inventionUseToner has a high circularity and an average circularity of 0.950.−By setting the standard deviation of circularity to less than 0.040 at 0.995, the transferability of a toner having a small particle diameter, which has been difficult in the past, is greatly improved and the developing ability for a low potential latent image is remarkably improved. improves.
[0020]
  Specifically, in the toner-based circle-equivalent diameter-circularity scattergram measured by the flow type particle image measuring apparatus, the circle-equivalent number average diameter of the toner is 2−10 μm and average circularity of 0.950−Dry type with 0.995 and circularity standard deviation less than 0.040oneComponent toner.
[0021]
  The equivalent circle diameter, circularity, and frequency distribution of the toner used in the present invention are used as a simple method for quantitatively expressing the shape of the toner particles. In the present invention, flow type particle image measurement is used. Measurement was performed using an apparatus FPIA-1000 (manufactured by Toa Medical Electronics Co., Ltd.), and calculation was performed using the following equation.
[0022]
[Expression 1]
[0023]
  Here, the “particle projected area” is the area of the binarized toner particle image, and the “peripheral length of the particle projected image” is the length of the contour line obtained by connecting the edge points of the toner particle image. Define.
[0024]
  In the present invention, the circularity is an index indicating the degree of unevenness of the toner particles, and is 1.000 when the toner particles are completely spherical. The more complicated the surface shape, the smaller the circularity.
[0025]
  In the present invention, a circle-equivalent number average diameter d means an average value of the number-based particle size frequency distribution of toner.₁The particle size standard deviation SDd is calculated from the following equation where the particle size (center value) at the division point i of the particle size distribution is di and the frequency is fi.
[0026]
[Expression 2]
[0027]
  Further, the average circularity c and the circularity standard deviation SDc, which mean the average value of the circularity frequency distribution, are ci and circularity (center value) at the division point i of the particle size distribution, and frequency is f._ciThen, it is calculated from the following equation.
[0028]
[Equation 3]
[0029]
  As a specific measurement method, 10 ml of ion-exchanged water from which impure solids and the like are previously removed is prepared in a container, and a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant therein, and then further measurement is performed. Add 0.02 g of sample and disperse uniformly. As a means for dispersion, an ultrasonic disperser UH-50 type (manufactured by SMT Co., Ltd.) equipped with a titanium alloy tip of φ5 mm as a vibrator is used, and a dispersion for measurement is made using a dispersion treatment for 5 minutes. In that case, it cools suitably so that the temperature of this dispersion may not be 40 degreeC or more.
[0030]
  To measure the shape of the toner particles, the flow particle image measuring device is used, and the toner particle concentration at the time of measurement is 3000−The concentration of the dispersion is readjusted to 10,000 particles / μl, and 1000 or more toner particles are measured. After the measurement, using this data, the equivalent circle diameter of the toner, the circularity frequency distribution, and the like are obtained.
[0031]
  The wax component used in the toner of the present invention includes petroleum wax such as paraffin wax, microcrystalline wax, petrolactam and derivatives thereof, montan wax and derivatives thereof, hydrocarbon wax and derivatives thereof by Fischer-Tropsch method, polyethylene Representative polyolefin waxes and derivatives thereof, carnauba wax, candelilla wax, natural waxes and derivatives thereof, etc., including derivatives, oxides, block copolymers with vinyl monomers, 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 derivatives thereof, styrene monomers such as vegetable waxes and animal waxes There 40−Any one having a temperature of 80 ° C. can be used.
[0032]
  Of these, polyolefin, Fischer-Tropsch hydrocarbon wax, petroleum wax, higher alcohol, or higher ester can further improve the developability and transferability.
[0033]
  The wax component described above is 1 per 100 parts by mass of the binder resin.−It is preferable to use 30 parts by mass.
[0034]
  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 a method for directly obtaining toner particles by a polymerization method, a monomer for forming them is used. Specifically, styrene; styrene monomers such as o- (m-, p-) methylstyrene, m- (p-) ethylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate, (meth ) Propyl acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ( (Meth) acrylic acid ester monomers such as dimethylaminoethyl acrylate and diethylaminoethyl (meth) acrylate; ene monomers such as butadiene, isoprene, cyclohexene, (meth) acrylonitrile and acrylamide Preferably used. These can be used alone or generally in the publication Polymer Handbook 2nd edition III-P139.−The theoretical glass transition temperature (Tg) described in 192 (John Wiley & Sons) is 40.−Monomers are appropriately mixed and used so as to exhibit 75 ° C. When the theoretical glass transition temperature is less than 40 ° C., problems are likely to occur from the viewpoint of storage stability and durability stability of the toner. In particular, in the case of a color toner for forming a full-color image, the color mixing property at the time of fixing each color toner is lowered, the color reproducibility is poor, and the transparency of the OHP image is further lowered.
[0035]
  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 low softening point material is encapsulated with an outer shell resin, as a specific GPC measurement method, the toner was previously extracted with a toluene solvent using a Soxhlet extractor for 20 hours. Then, after removing toluene with a rotary evaporator to obtain an extract, 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. A sample (THF solution) obtained by filtering a solution obtained by dissolving the residue in tetrahydrofuran (THF) through a solvent-resistant membrane filter having a pore diameter of 0.3 μm is measured using 150C manufactured by Waters. The column structure can connect Showa Denko A-801, 802, 803, 804, 805, 806 and 807, and measure the molecular weight distribution using a standard polystyrene resin calibration curve. The main peak molecular weight of the binder resin according to the present invention is 5000.−1 million, the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 2−Those showing 100 are preferred for the present invention.
[0036]
  Examples of the colorant used in the toner used in the present invention include the following yellow colorant, magenta colorant, and cyan colorant. As the black colorant, carbon black, a magnetic material, or the following yellow colorant / magenta A colorant / cyan colorant mixed to black is used.
[0037]
  As the yellow colorant, a condensed azo compound, an isoindolinone compound, an anthraquinone compound, an azo metal complex, a methine compound, or an allylamide compound is used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 168 or 180 are preferably used.
[0038]
  As the magenta colorant, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds or perylene compounds are used. Specifically, C.I. 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, 185, 202, 206, 220, 221 or 254 is particularly preferably used.
[0039]
  As the cyan colorant, a copper phthalocyanine compound and a derivative thereof, an anthraquinone compound, a basic dye lake compound, or the like can be used. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, or 66 is particularly preferably used.
[0040]
  These colorants can be used alone or in combination and further in the form of a solid solution. The colorant is selected from the viewpoints of hue, saturation, brightness, weather resistance, OHP transparency, and dispersibility in the toner particles. The amount of the colorant added is 1 with respect to 100 parts by mass of the resin component.−It is preferable to use 20 parts by mass.
[0041]
  When a magnetic material is used as a black colorant, unlike other colorants, it is 40 with respect to 100 parts by mass of the resin.−It is preferable to use 150 parts by mass.
[0042]
  A known charge control agent can be used in combination with the toner used in the present invention. Particularly, a charge control agent that has a high charging speed and can stably maintain a constant charge amount is preferable. Further, when the toner particles are directly polymerized, a charge control agent having no polymerization inhibition and no solubilized product in an aqueous dispersion medium is preferable.
[0043]
  Specific compounds include metal compounds of aromatic carboxylic acids such as salicylic acid, naphthoic acid and dicarboxylic acid as negative charge control agents; polymer compounds having a sulfonic acid or carboxylic acid group in the side chain; boron compounds; urea Compound; silicon compound; calixarene and the like. Examples of the positive charge control agent include quaternary ammonium salts; polymer type compounds having the quaternary ammonium salt in the side chain; guanidine compounds; imidazole compounds.
[0044]
  However, in the present invention, it is not essential to add a charge control agent. When a two-component development method is used, friction charging with a carrier is used, and when a non-magnetic one-component blade coating development method is used, It is not always necessary to include a charge control agent in the toner particles by actively utilizing frictional charging with the blade member or the sleeve member.
[0045]
  Addition of inorganic fine powder to the toner used in the present invention is a preferred embodiment for improving developability, transferability, charging stability, fluidity and durability. As the inorganic fine powder, known ones can be used, and it is particularly preferred to be selected from silica, alumina, titania or a double oxide thereof. Further, silica is more preferable. For example, the silica can be either a so-called dry process produced by vapor phase oxidation of silicon halide or alkoxide, or a dry silica called fumed silica and a so-called wet silica produced from alkoxide or water glass. There are few silanol groups on the surface and in the silica fine powder, and Na₂O or SO₃ ^2-For example, dry silica with less production residue is preferred. In addition, in dry silica, it is possible to obtain composite fine powders of silica and other metal oxides by using other metal halogen compounds such as aluminum chloride and titanium chloride together with silicon halogen compounds in the production process. Yes, including them.
[0046]
  The inorganic fine powder used in the toner used in the present invention has a specific surface area of 30 m by nitrogen adsorption measured by the BET method.²/ G or more, especially 50−400m²/ G range gives good results, silica fine powder 0.1% to 100 parts by mass of toner.−8 parts by weight, preferably 0.5−It is particularly good to use 5 parts by weight, more preferably more than 1.0 to 3.0 parts by weight.
[0047]
  In addition, the inorganic fine powder used in the toner used in the present invention is optionally made of silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, silane coupling for the purpose of hydrophobization, chargeability control, etc. It is also possible to treat with an agent, a silane coupling agent having a functional group, another organic silicon compound, an organic titanium compound, or a combination of various treatment agents.
[0048]
  The specific surface area was calculated 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.
[0049]
  In order to maintain a high charge amount and achieve a low consumption and a high transfer rate, the inorganic fine powder is more preferably treated with at least silicone oil.
[0050]
  In the toner used in the present invention, other additives within a range that does not have a substantial adverse effect, for example, lubricant powder such as polytetrafluoroethylene powder, zinc stearate powder, polyvinylidene fluoride powder; cerium oxide powder, Polishing agents such as silicon carbide powder and strontium titanate powder; fluidity imparting agents such as titanium oxide powder and aluminum oxide powder; anti-caking agents or conductivity imparting such as carbon black powder, zinc oxide powder and tin oxide powder In addition, a small amount of a reverse polarity organic fine particle and inorganic fine particle can also be used as a developability improver.
[0051]
  As a method for producing the toner used in the present invention, a resin, a release agent composed of a low softening point substance, a colorant, a charge control agent, and the like were uniformly dispersed using a pressure kneader, an extruder, or a media dispersing machine. After that, after colliding with a target under a mechanical or jet stream, and pulverizing to a desired toner particle size (adding toner particle smoothing and spheroidizing steps if necessary), the particle size is passed through a classification step. In addition to a method for producing toner by a pulverization method in which the toner has a sharp distribution and a toner is obtained, a spherical toner is obtained by atomizing a molten mixture into air using a disk or a multi-fluid nozzle described in JP-B-56-13945 In addition, the toner is directly added using suspension polymerization methods disclosed in Japanese Patent Publication Nos. 36-10231, 59-53856 and 59-61842. And a direct polymerization in the presence of a water-soluble polar polymerization initiator using a water-based organic solvent that is soluble in the monomer and insoluble in the resulting polymer, or directly in the presence of a water-soluble polar polymerization initiator to produce a toner. The toner can be produced using an emulsion polymerization method represented by a soap-free polymerization method.
[0052]
  In the method of producing toner using the pulverization method, it is difficult to keep the shape of the toner particles within a desired circularity frequency distribution range. In the melt spray method, a certain degree of circularity can be obtained. In addition, the particle size distribution of the obtained toner tends to be wide, and it is difficult to control the surface state of the toner. On the other hand, in the dispersion polymerization method, the obtained toner shows a very sharp particle size distribution, but the production equipment is used from the viewpoint of the processing of the waste solvent and the flammability of the solvent due to the narrow selection of materials to be used and the use of organic solvents. Complex and easy to complicate. The emulsion polymerization method represented by soap-free polymerization is effective because the particle size distribution of the toner is relatively uniform, but the used emulsifier and polymerization initiator terminals are present on the surface of the toner particles, and the environmental characteristics are likely to deteriorate.
[0053]
  In the present invention, it is important to control the frequency distribution of the circularity of toner particles.−Using an emulsion polymerization method or suspension polymerization method under normal pressure or under pressure to obtain a 6 μm fine particle toner, the polymer is preliminarily shaped using a medium, or the polymer is directly applied to a pressure impingement plate. A method of colliding, and further a method of freezing the obtained polymer in an aqueous system or agglomerating and coalescing particles having a salt break or opposite surface charge by considering conditions such as pH. Is particularly preferred. Furthermore, a seed polymerization method in which a monomer is further adsorbed to the obtained polymer particles and then polymerized using a polymerization initiator can be suitably used in the present invention. Of these, the suspension polymerization method is particularly preferred in the present invention.
[0054]
  When the direct polymerization method is used as a toner production method, the control of the toner particle circularity frequency distribution and particle size frequency distribution changes the kind and addition amount of a poorly water-soluble inorganic salt and a protective colloid dispersing agent. Predetermined toner particles can be obtained by controlling the method and mechanical device conditions (for example, the circumferential speed of the rotor, the number of passes, the stirring conditions such as the shape of the stirring blades and the shape of the container) or the solid content concentration in the aqueous solution. it can. Further, as described above, predetermined toner particles can be obtained also by adjusting the stirring conditions and the processing time of the conical dryer used for drying the toner particles.
[0055]
  Further, when the toner is heated and dried, the toner particles can be spheroidized. For example, by using a fluidized bed dryer and adjusting the stirring conditions of the rotor blades and the processing time, the toner particle shape is preferable. Can be.
[0056]
  By specifying the physical properties of the wax component as described above, the toner of the present invention can minimize the influence of toner coarsening and the wax component on the spheroidizing treatment of the toner particles as described above. It can be very effective because it can.
[0057]
  When the toner is produced by the direct polymerization method, examples of the polymerization initiator used include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1. Azo or diazo polymerization initiators such as' -azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile and azobisisobutyronitrile; benzoyl peroxide Peroxide-based polymerization initiators such as methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, 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, but is generally 0.5 to 20% by mass based on the polymerizable monomer. The kind of the polymerization initiator is slightly different depending on the polymerization method, but is used alone or in combination with reference to the 10-hour half-life temperature.
[0058]
  In order to control the degree of polymerization, a known crosslinking agent, chain transfer agent, polymerization inhibitor or the like may be further added and used.
[0059]
  When a suspension polymerization method using a dispersion stabilizer is used as a toner production method, the dispersion stabilizer used is an inorganic compound such as tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, Examples include magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, and alumina. Examples of the organic compound include polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, carboxymethyl cellulose sodium salt, polyacrylic acid and its salt, starch and the like. These can be used by dispersing in an aqueous phase. These dispersion stabilizers are 0.2 to 100 parts by mass of the polymerizable monomer.−It is preferable to use 20 parts by weight.
[0060]
  When an inorganic compound is used as the dispersion stabilizer, a commercially available product may be used as it is, but in order to obtain fine particles, fine particles of the inorganic compound may be generated in a dispersion medium. For example, in the case of tricalcium phosphate, it is preferable to mix an aqueous sodium phosphate solution and an aqueous calcium chloride solution under high-speed stirring.
[0061]
  Due to the fine dispersion of these dispersion stabilizers, 0.001−You may use 0.1 mass part surfactant together. This is to promote the intended action of the dispersion stabilizer, for example, sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate. And calcium oleate.
[0062]
  When the direct polymerization method is used as a method for producing the toner used in the present invention, the following production method is possible.
[0063]
  A release agent composed of a low softening point substance, a colorant, a charge control agent, a polymerization initiator and other additives were added to the polymerizable monomer, and the mixture was uniformly dissolved or dispersed by a homogenizer or an ultrasonic disperser. The monomer composition is dispersed in an aqueous phase containing a dispersion stabilizer by a normal stirrer, homomixer or homogenizer. Preferably, granulation is performed by adjusting the stirring speed and stirring time so that the droplets of the monomer composition have the desired toner particle size. Thereafter, stirring may be performed to such an extent that the particle state is maintained and the sedimentation of the particles is prevented by the action of the dispersion stabilizer. The polymerization temperature is 40 ° C. or higher, generally 50−The polymerization is preferably performed at a temperature of 90 ° C. The temperature may be raised in the latter half of the polymerization reaction, and for the purpose of improving durability in the image forming method of the present invention, in order to remove unreacted polymerizable monomers and by-products, the latter half of the reaction, or After completion of the reaction, a part of the aqueous medium may be distilled off from the reaction system. After completion of the reaction, the produced toner particles are recovered by washing and filtration and dried. In the suspension polymerization method, water 300 is usually used for 100 parts by mass of the monomer composition.−3000 parts by weight are preferably used as the dispersion medium.
[0064]
  The electrophotographic apparatus of the present invention includes a process cartridge that employs a method in which a surface of an elastic roller serving as a developing roller is coated with toner as a one-component developer and brought into contact with the surface of a photoreceptor. The toner is preferably a non-magnetic toner, but may be a magnetic toner. It is important that the toner on the developing roller is in contact with the surface of the photoreceptor. The toner carrier is substantially in contact with the surface of the photoreceptor, which means that the toner carrier is in contact with the photoreceptor when the toner is removed from the toner carrier. At this time, in order to obtain a toner image having no edge effect by the electric field acting between the photosensitive member and the developing roller facing the surface of the photosensitive member via the toner, a potential is applied to the surface of the developing roller or in the vicinity of the surface of the developing roller. It is necessary to form an electric field between the surface of the photoreceptor and the surface of the toner carrier. For this reason, the elastic rubber of the developing roller is resistance controlled to the middle resistance region to form an electric field while preventing conduction with the surface of the photoreceptor, or a thin dielectric layer is provided on the surface layer of the conductive roller. Can be any configuration in which a conductive resin sleeve on the side facing the surface of the photoconductor is covered with an insulating material on a conductive roller, or a conductive layer is provided on the side of the insulating sleeve that does not face the photoconductor. .
[0065]
  In the present invention, the developing roller carrying the toner may be rotated in the same direction as the circumferential speed of the photosensitive member, or may be rotated in the opposite direction. When the rotation is in the same direction, the peripheral speed ratio is 100% or more, more preferably 120% with respect to the peripheral speed of the photoreceptor.−300%, more preferably 140−A peripheral speed difference should be generated by setting it to 250%. If it is less than 100%, there may be a problem in image quality such as poor line cutting. As the peripheral speed ratio increases, the amount of toner supplied to the development site increases, the frequency of toner desorption with respect to the latent image increases, and unnecessary portions are scraped off and applied to the necessary portions. An image faithful to the latent image can be obtained.
[0066]
  The present invention does not include a two-component developing method using a magnetic brush in which toner is formed from a magnetic carrier.
[0067]
  As the cleaning member used in the present invention, a blade, a roller, a fur brush, a magnetic brush, or the like can be used. Two or more of these cleaning members may be used in combination.
[0068]
  The electrophotographic photoreceptor used in the present invention has a structure in which a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material are laminated in this order on a conductive support, or on a conductive support. The charge generation layer containing the charge generation material and the charge transport layer containing the charge transport material are stacked in this order.
[0069]
  The charge transport layer of the photoreceptor used in the present invention has a universal hardness HU at an indentation depth of 1 μm from the surface.248N / mm²more than254N / mm²The elastic deformation rate is37%more than43.2% or lessAnd the universal hardness HU at the indentation depth of 5 μm from the surface is290N / mm²more than305 N / mm ² Less thanThe elastic deformation rate is33.9%more than38.2% or lessNeed to be.
[0070]
  As a result of intensive studies, the present inventors paid attention to the hardness and deformation rate of the charge transport layer of the electrophotographic photosensitive member, and obtained a universal hardness value (HU) And elastic deformation rate (plastic deformation rate) are more than a certain value, it is possible to maintain the toner cleaning property and the durability of the photoreceptor while maintaining the developing property of the spherical toner in the contact developing method. I found out.
[0071]
  The universal hardness near the surface of the charge transport layer in the electrophotographic photosensitive member, that is, the universal hardness HU at an indentation depth of 1 μm from the surface is248N / mm²In the electrophotographic apparatus of the present invention, the mechanical strength of the photosensitive member is not sufficient, and the elastic deformation rate at the indentation depth of 1 μm from the surface is low.37If it is less than%, the toner cleaning property is not sufficient, and toner fusion due to embedding of the toner external additive or the like is caused. Moreover, the universal hardness HU at the indentation depth of 1 μm from the surface is254N / mm²If it is larger, the amount of wear of the photoconductor charge transport layer is reduced, so that blade turning occurs.
[0072]
  On the other hand, the universal hardness inside the charge transport layer in the electrophotographic photosensitive member, that is, the universal hardness HU at an indentation depth of 5 μm from the surface is290N / mm²Or the elastic deformation rate is less than33.9If it is less than%, the electrophotographic apparatus of the present invention is not sufficiently durable against scratches and uneven wear in the charge transport layer during repeated use of the photoreceptor, and in particular causes the occurrence of streaky toner cleaning defects. The wound that grows deeper.
[0073]
  The surface hardness of the charge transport layer of the electrophotographic photosensitive member in the present invention is a universal hardness (HU: unit N / mm) by an instrumentation indentation method.²) To measure.
[0074]
  In the present invention, the universal hardness is Helmut Fisher GMBH + Co. It measured using FISHERSCOPE H100V made from. The sample was formed on a glass plate with a film thickness of 18 μm. The measurement was performed by applying a constant load to the indenter and changing the indentation depth of the indenter to 1 μm and 5 μm. In addition, the elastic deformation rate can be analyzed for the elastic energy (plastic energy) of the film by reducing the load of the indenter at the time of universal hardness measurement. The elastic deformation rate (plastic deformation rate) is obtained from the work (energy) performed by the indenter on the membrane, that is, the change in energy due to the increase or decrease of the load of the indenter on the membrane, and the value can be obtained from the following equation;
  Elastic deformation rate (%) = energy required for elastic deformation / (energy required for plastic deformation + energy required for elastic deformation)
[0075]
  Specific examples of the photoreceptor of the present invention will be described below.
[0076]
  The support used in the photoreceptor of the present invention may be any material having conductivity, and examples thereof include metals such as aluminum and stainless steel, metals provided with a conductive layer, paper, plastics, and the like. A cylindrical shape etc. are mentioned. In particular, when the image input of LBP or the like 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 powder such as carbon black or metal particles in a binder resin. The thickness of the conductive layer is 5−40 μm is preferred, especially 10−30 μm is preferable.
[0077]
  An intermediate layer having an adhesive function and a barrier function can be provided thereon as necessary. Examples of the material for the intermediate layer include polyamide, polyvinyl alcohol, polyethylene oxide, ethyl cellulose, casein, polyurethane, and polyether urethane. These are dissolved in an appropriate solvent and applied. The film thickness of the intermediate layer is 0.05−5 μm is preferable, particularly 0.3−1 μm is preferred.
[0078]
  A charge generation layer is formed on the conductive support or the intermediate layer. Examples of the charge generating material used in the present invention include selenium-tellurium, pyrylium, thiapyrylium dyes, phthalocyanine, anthanthrone, dibenzpyrenequinone, trisazo, cyanine, disazo, monoazo, indigo, quinacridone, and asymmetric quinocyanine pigments. Can be mentioned. The charge generation layer contains 0.3% of the charge generation material.−Disperse thoroughly using a homogenizer, ultrasonic dispersion, ball mill, vibration ball mill, sand mill, attritor, roll mill, liquid collision type high-speed disperser, etc. together with 4 times the amount of binder resin and solvent, and apply and dry the dispersion. Formed. The film thickness of the charge generation layer is preferably 5 μm or less, in particular 0.1−2 μm is preferred.
[0079]
  The charge transport layer is formed by applying and drying a paint in which a charge transport material and a binder resin are mainly 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 0.5−Combined with twice the amount of binder resin, applied and dried to form a charge transport layer.
[0080]
  The thickness of the charge transport layer is 5−Preferably it is 40 μm.−More preferably, it is 30 μm, especially 10 in the contact development process.−More preferably, it is 20 μm.
[0081]
  Binder resin used for charge transport layerIs, Polyarylate resinAnd thatThe weight average molecular weight (Mw) is preferably 50,000 or more and 200,000 or less. If it is less than 50000, the mechanical strength as a binder resin will be insufficient, and the wear resistance of the charge transport layer and toner fusion will tend to occur. If it exceeds 200,000, the viscosity of the paint for the charge transport layer will be too high. The coatability is extremely deteriorated, and the productivity is easily lowered.
[0082]
  The charge transport layer of the electrophotographic photosensitive member used in the present invention has a universal hardness HU at an indentation depth of 1 μm from the surface.248N / mm²more than254N / mm²The elastic deformation rate is37%more than43.2% or lessAnd the universal hardness HU at the indentation depth of 5 μm from the surface is290N / mm²more than305 N / mm ² Less thanThe elastic deformation rate is33.9%more than38.2% or lessHowever, in the charge transport layer in which the low molecular weight charge transport material as described above is dispersed in the binder resin, the mechanical strength and deformation rate of the film are the same as the mechanical strength of the binder resin and the charge transport material. It depends greatly on the content of. In addition, since the low molecular weight charge transport material is molecularly dispersed, the mechanical strength and deformation rate of the film of the charge transport layer differ depending on the dispersion state between the vicinity of the surface and the inside. In particular, the dispersion state of the charge transport material in the charge transport layer varies depending on the drying conditions of the film when forming the charge transport layer. Therefore, in order to obtain the charge transport layer used in the present invention by a film in which a low molecular weight charge transport material is dispersed in a binder resin, a polyarylate resin is used as the binder resin.GreasyIt is necessary to select a resin having a high hardness and a high molecular weight and to further reduce the content of the charge transport material having a low molecular weight. Furthermore, by selecting appropriate drying conditions, it is possible to form a charge transport layer having different hardness and elastic deformation rate near and inside the surface of the film as in the present invention.
[0083]
  Since the hardness of the charge transport layer is determined by many factors as described above, it is not unconditionally determined. However, depending on the combination of the binder resin and the charge transport material, the mixing ratio, and the selection of drying conditions, an indentation depth of 1 μm from the surface Universal hardness HU248N / mm²more than254N / mm²The elastic deformation rate is37%more than43.2% or lessAnd the universal hardness HU at the indentation depth of 5 μm from the surface is290N / mm²more than305 N / mm ² Less thanThe elastic deformation rate is33.9%more than38.2% or lessIs achieved.
[0084]
  Various additives can be added to the charge transport layer of the photoreceptor used in the present invention. The additive is a deterioration inhibitor such as an antioxidant and an ultraviolet absorber.
[0085]
【Example】
  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to this. In the examples, “parts” means parts by mass.
[0086]
  The electrophotographic apparatus of the present invention will be described with reference to FIG. As an example of an apparatus such as a copying machine or a printer as an electrophotographic apparatus of the present invention, there is an apparatus shown in FIG. 2, and the developing means 2 contains toner T. The toner T is a nonmagnetic toner.
[0087]
  The surface of the photosensitive member 6 is charged by a charging unit (for example, a charging roller, a charging brush, a charging blade, or the like which is a contact charging unit) to which a voltage is applied by a bias applying unit, and exposure light (for example, laser light or halogen). An electrostatic charge image is formed on the photoreceptor 6 by the light L of the lamp. Toner application blade (for example, elastic blade, metal blade, etc.) 3, 10³-10⁹The electrostatic charge image is developed with the toner T accommodated in the developing means 2 having the developing roller 4 having an elastic layer or dielectric layer having a medium resistance of Ω · cm on the surface. For the development, a regular development system or an anti-ream development system is used. In the developing unit, a DC bias or an alternating bias is applied to the developing roller 7 by a bias applying unit as required. When the transfer material 8 is conveyed and arrives at the transfer portion, the back surface of the transfer material 8 (from the photosensitive member 6 side) is transferred by a transfer means (for example, a transfer roller or a transfer belt) 7 to which a voltage is applied by a bias applying means. The toner image on the surface of the photoreceptor 6 is electrostatically transferred onto the transfer material 8 by charging while pressing from the opposite side. In some cases, the toner image on the photosensitive member 6 may be transferred to an intermediate transfer member (not shown) (for example, an intermediate transfer drum or an intermediate transfer belt), and the toner image may be transferred from the intermediate transfer member to the transfer material 8. .
[0088]
  The toner image on the transfer material P separated from the photoreceptor 6 is fixed to the transfer material 8 by a heating and pressing means (for example, a heating and pressing roller fixing means). The toner remaining on the photoconductor 6 after the transfer process is removed from the surface of the photoconductor 6 by a cleaning means 9 (for example, a cleaning blade, a cleaning roller, a cleaning brush, etc.) if necessary. After the cleaning, the process starting from the charging process is repeated by the charging unit 1 again.
[0089]
  FIG. 3 is a schematic sectional view showing a specific example of the process cartridge taken out from the electrophotographic apparatus main body. In the process cartridge, the developing means and the electrostatic charge image holding member are at least integrally formed as a cartridge, and the process cartridge is formed so as to be detachable from the main body of the electrophotographic apparatus (for example, a copying machine or a laser beam printer). In the process cartridge shown in FIG. 3, a developing roller (elastic roller) 4 is installed in the developing unit 2 so as to be pressed so that a nip portion is formed on the photosensitive drum 6. An application roller 5 is provided in pressure contact. Further, a charging roller 1 and a cleaning blade 9 are provided in pressure contact with the photosensitive drum 6.
[0090]
  In the image forming method of the present invention, it is preferable that the photosensitive member and the toner carrier are in contact with each other through the toner, and either the photosensitive member or the toner carrier is an elastic body, a flexible belt, or a tube. . For example, there is a combination of a photosensitive drum-developing elastic roller, a photosensitive drum-developing flexible tube, and a photosensitive belt-developing elastic roller.
[0091]
  [Example of toner production]
  650 g of ion-exchanged water and 0.1 mol / liter-Na in a 2-liter four-necked flask equipped with a high-speed stirring device TK type homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.)₃PO₄500 g of an aqueous solution was added, the rotation speed was adjusted to 12000 rpm, and the mixture was heated to 70 ° C. Here 1.0 mol / liter-CaCl₂Gradually add 70 parts of an aqueous solution to form a slightly water-insoluble dispersion stabilizer Ca₃(PO₄)₂An aqueous dispersion medium containing was prepared.
[0092]
  On the other hand, as dispersoid,
  78 parts of styrene
  2-ethylhexyl acrylate 22 parts
  0.2 parts of divinylbenzene
  Carbon black (particle size = 45nm) 5 parts
  Polycarbonate resin (peak molecular weight = 7000) 5 parts
  2 parts of chromium compound of di-tert-butylsalicylic acid
  Ester wax (mp = 62 ° C) 10 parts
The mixture consisting of 1 is dispersed for 3 hours using an attritor (manufactured by Mitsui Kinzoku Co., Ltd.), and 10 parts of 2,2′-azobis (2,4-dimethylvaleronitrile) is added to prepare a polymerizable monomer composition. did.
[0093]
  Next, the polymerizable monomer composition is put into the aqueous dispersion medium, and N₂While maintaining the rotation speed of the high-speed stirrer at 12000 rpm in an atmosphere, the mixture was stirred for 15 minutes to granulate the polymerizable monomer composition. Thereafter, the stirrer was changed to a propeller stirring blade and held at the same temperature for 5 hours while stirring at 50 rpm, and further heated to 80 ° C. and held for 10 hours to complete the polymerization.
[0094]
  After completion of the polymerization, the suspension was cooled, and then diluted hydrochloric acid was added to remove the dispersion stabilizer. Further, after washing with water several times, the toner particles are spheroidized and dried for 10 hours while stirring in hot air using a fluidized bed dryer (manufactured by Okawara Seisakusho) to obtain polymer particles (A). It was.
[0095]
  The polymer particle (A) has a circle-equivalent number average diameter of 4.1 μm, an average circularity in a circularity frequency distribution of 0.990, a circularity standard deviation of 0.030, and a molecular weight distribution by GPC. The peak molecular weight was 15,000 and Mw / Mn was 18.
[0096]
  100 parts of the above polymer particles (A) and hydrophobic oil-treated silica fine powder (BET; 200 m²/ G) 2 parts were dry-mixed with a Henschel mixer (Mitsui Metals Co., Ltd.) to prepare the toner of the present invention.
[0097]
  <Photoconductor Production Example 1>
  An aluminum cylinder having a diameter of 30 mm was used as a support, and a coating composed of the following materials was applied on the support by dip coating, followed by thermosetting at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 15 μm.
[0098]
  Conductive pigment: SnO₂Coated barium sulfate 10 parts
  Resistance control pigment: Titanium oxide 2 parts
  Binder resin: 6 parts of phenol resin
  Leveling material: 0.001 part of silicone oil
  Solvent: methanol / methoxypropanol = 0.2 / 0.8 20 parts
[0099]
  Next, a solution obtained by dissolving 3 parts of N-methoxymethylated nylon and 3 parts of copolymer nylon in a mixed solvent of 65 parts of methanol / 30 parts of n-butanol was applied onto this conductive layer by a dipping method. An intermediate layer of 0.5 μm was formed.
[0100]
  Next, 4 parts of TiOPc and polyvinyl butyral having strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 ° of the Bragg angles (2θ ± 0.2 °) in the characteristic X-ray diffraction of CuKα (Product name: ESREC BM2, manufactured by Sekisui Chemical Co., Ltd.) 2 parts and 60 parts of cyclohexanone were dispersed in a sand mill apparatus using φ1 mm glass beads for 4 hours, and then 100 parts of ethyl acetate was added to prepare a dispersion for charge generation layer. This was applied by a dipping method to form a charge generation layer having a thickness of 0.3 μm.
[0101]
  Next, in order to form a charge transport layer, 10 parts of a polyarylate resin (Mw = 101000) having a structural unit represented by the following formula:
[0102]
[Chemical 1]
[0103]
  7 parts of an amine compound of the formula
[0104]
[Chemical 2]
[0105]
Using a coating for a charge transport layer prepared by dissolving in a mixed solvent of 50 parts of monochlorobenzene and 50 parts of monochlorobenzene, this paint is applied onto the charge generation layer by a dipping method and dried at 100 ° C. for 1 hour. Then, a charge transport layer having a film thickness of 18 μm was formed, and the photoreceptor 1 was produced. Table 1 shows the universal hardness and elastic deformation rate of the charge transport layer.
[0106]
  <Photoconductor Production Example 2>
  Photoreceptor 2 was produced in the same manner as Photoreceptor Production Example 1, except that the amine compound used in Photoreceptor Production Example 1 was changed from 7 parts to 5 parts. Table 1 shows the universal hardness and elastic deformation rate of the charge transport layer.
[0107]
  <Photoconductor Comparative Production Example 1>
  In the same manner as in photoreceptor production example 1, a support, a conductive layer, an undercoat layer, and a charge generation layer were formed.
[0108]
  Next, in place of the polyarylate resin used in Production Example 1, 25 parts of a Z-type polycarbonate resin having a weight average molecular weight Mw of 40,000 was dissolved in a mixed solvent of 50 parts of monochlorobenzene / 20 parts of dichloromethane. An electrophotographic photosensitive member is formed by applying the coating layer onto the charge generation layer by dipping and drying at 100 ° C. for 1 hour to form a charge transport layer having a thickness of 18 μm.3Got. Table 1 shows the universal hardness and elastic deformation rate of the charge transport layer at this time.
[0109]
  <Photoconductor Comparative Production Example 2>
  Photoconductor in the same manner as in Photoconductor Production Example 1, except that the amine compound used in Photoconductor Production Example 1 was changed from 7 parts to 10 parts.4Was made. Table 1 shows the universal hardness and elastic deformation rate of the charge transport layer at this time.
[0110]
  <Photoconductor Comparative Production Example 3>
  Photoconductor in the same manner as in Photoconductor Production Example 1 except that the drying condition for forming the charge transport layer in Photoconductor Production Example 1 was 1 hour at 125 ° C.5Was made. Table 1 shows the universal hardness and elastic deformation rate of the charge transport layer at this time.
[0111]
  <Photoconductor Comparative Production Example 4>
  In the same manner as in photoreceptor production example 1, a support, a conductive layer, an undercoat layer, and a charge generation layer were formed.
[0112]
Next, 7 parts of a styryl compound of the formula
[0113]
[Chemical 3]
[0114]
And 10 parts of a polycarbonate resin (Mw = 18000) having a structural unit of the following formula
[0115]
[4]
[0116]
Using a coating material for a charge transport layer prepared by dissolving in a mixed solvent of 50 parts of monochlorobenzene / 20 parts of dichloromethane, and applying the paint on the charge generation layer by a dipping method.1 hour at 125 ° CDry to form a charge transport layer with a film thickness of 18 μm,Photoconductor6Was made. Table 1 shows the universal hardness and elastic deformation rate of the charge transport layer at this time.
[0117]
[Table 1]
[0118]
  Example 1
  A modified Hewlett-Packard LBP “Laser Jet 4000” (process speed 94.2 mm / sec) was used as the electrophotographic apparatus. The outline of the apparatus will be described with reference to FIG. This apparatus uses a charging roller 1 to uniformly charge a photosensitive member (photosensitive drum having a diameter of 30 mm) 6. After charging, the image portion is exposed with a laser beam to form an electrostatic latent image, and a visible image (toner image) is formed with toner, and then the toner image is transferred to a transfer material 8 by a transfer roller 7 to which voltage is applied. To do.
[0119]
  The equipment was modified as follows. The photosensitive member was charged by constant voltage control using only a DC power source as a high voltage power source.
[0120]
  The developing part 2 in the process cartridge was modified as follows. An electric resistance value of 10 made of urethane foam instead of an aluminum sleeve containing a magnet as a toner supply body⁵A medium resistance rubber roller (diameter 16 mm; core metal 6 mm, Asker C hardness = 48 degrees, Rz = 6.8 μm) having Ω · cm was used as the developing roller 4, and contacted with the photosensitive drum 6 so that the nip was about 3 mm. The rotational peripheral speed of the developing roller was the same direction at the contact portion with the photoconductor, and the developing roller was driven to be 150% with respect to the peripheral speed of the photoconductor. The peripheral speed of the developing roller was 141.3 mm / second, and the peripheral speed of the photoreceptor surface was 94.2 mm / second.
[0121]
  As a means for applying toner to the developing roller 4, an applying roller 5 is provided inside the developing container 2 and brought into contact with the developing roller 4. The toner was applied onto the developing roller 4 by rotating in the opposite direction to the developing roller 4 at the contact portion. Further, a stainless steel blade 3 coated with a resin for controlling the toner coating layer on the developing roller 4 was attached. A blade 9 was used in the cleaner container 10 as a cleaning member, and the setting pressure was set to 45 g / cm.
[0122]
  The photoconductor 1 of Production Example 1 was used as the photoconductor, the toner of the above Production Example was used as the toner, and process conditions were set so as to satisfy the following conditions.
[0123]
  Photoconductor dark part potential -600V
  Photoreceptor bright part potential -150V
  Development bias -450V (DC component only)
[0124]
  This machine was installed in an environment with a temperature and humidity of 23 ° C./60%, and while replenishing toner, a continuous image output test of 10000 sheets with a character pattern with an area ratio of 4% printed on A4 size paper was performed and evaluated. . Further, the surface roughness of the photoreceptor was measured before and after durability. The evaluation results are shown in Table 2.
[0125]
  (Example2 andAnd Comparative Examples 1 to 4)
  As the photosensitive member, the photosensitive member 2 to 2 in the production example described above.6Evaluation was performed in the same manner as in Example 1 except that was used. The results are shown in Table 2.
[0126]
  (Example3And Comparative Examples 5 and 6)
  In the electrophotographic apparatus of Example 1, the set pressure of the cleaning blade is 60 g / cm, and the photosensitive member is a photosensitive member.1 and 3, 5The same evaluation as in Example 1 was performed. The results are shown in Table 3.
[0127]
[Table 2]
[0128]
[Table 3]
[0129]
  As is apparent from Tables 2 and 3, the electrophotographic apparatus according to the embodiment of the present invention maintains the toner cleaning property and the durability of the photosensitive member while maintaining the developing property of the toner in the contact developing method using the spherical toner. Therefore, it is possible to stably provide high-quality and high-definition images for a long period of time.
[0130]
【The invention's effect】
  According to the present invention, in a contact developing type electrophotographic apparatus using a toner having a small diameter and high circularity as a toner, the charge transport layer of the electrophotographic photosensitive member has a universal hardness HU at an indentation depth of 1 μm from the surface.248N / mm²more than254N / mm²The elastic deformation rate is37%more than43.2% or lessAnd the universal hardness HU at the indentation depth of 5 μm from the surface is290N / mm²more than305 N / mm ² Less thanThe elastic deformation rate is33.9%more than38.2% or lessAs a result, it is possible to provide a high-quality, highly stable electrophotographic apparatus and process cartridge that maintain the toner developability and the toner cleaning property, suppress the mechanical abrasion of the photoreceptor during repeated image output, and provide high image quality and high stability. became.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of an electrophotographic apparatus of the present invention.
FIG. 2 is a schematic sectional view of an apparatus such as a copying machine or a printer as an electrophotographic apparatus of the present invention.
FIG. 3 is a schematic cross-sectional view of a process cartridge taken out from an electrophotographic apparatus main body.
[Explanation of symbols]
  1 Charging roller
  2 Development means
  3 Application blade
  4 Development roller
  5 Application roller
  6 Photoconductor
  7 Transfer roller
  8 Transfer material
  9 Cleaning blade
  10 Cleaning means
  11 Heating and pressing means
  L Exposure light
  T Toner

Claims (6)

An electrophotographic photosensitive member, charging means, developing means, transfer means, at least with an electrophotographic apparatus and a fixing means and cleaning means,
It said developing means to form a toner layer on the elastic roller, electrophotographic by while mutually rotate the elastic roller and said electrophotographic photosensitive member, contacting the toner layer on the surface of the electrophotographic photosensitive member A means for developing an electrostatic latent image formed on a photoreceptor with toner of the toner layer to form a toner image;
Circle-equivalent diameter based on the number of toner the toner is measured with a flow type particle image measuring device - in circularity scattergram circle-equivalent number average diameter 2 of the toner - a 10 [mu] m, and an average circularity of 0.950 - at 0.995, a dry one-component toner circularity standard deviation is less than 0.040,
A charge generation layer and a charge transport layer to the power terminal photoreceptor conductive substrate comprising an electrophotographic photosensitive member obtained by laminating in this order, the binder resin of the charge transport layer is a polyarylate resin, the charge Universal hardness HU at an indentation depth of 1 μm from the surface of the transport layer is 248 N / mm ² or more and 254 N / mm ² or less, an elastic deformation rate is 37 % or more and 43.2% or less, and an indentation depth of 5 μm from the surface electrophotographic apparatus, wherein the universal hardness HU is 290 N / mm ² or more 305N / mm ² or less elastic deformation rate is less than 38.2% or more 33.9% at. The weight average molecular weight of polyarylate resin electrophotographic apparatus according to claim 1, 200,000 hereinafter to 50,000.   The electrophotographic apparatus according to claim 1, wherein the toner is produced using a suspension polymerization method. A process cartridge configured to at least developing means and an electrophotographic photosensitive member to one body,
It said developing means to form a toner layer on the elastic roller, electrophotographic by while mutually rotate the elastic roller and said electrophotographic photosensitive member, contacting the toner layer on the surface of the electrophotographic photosensitive member A means for developing an electrostatic latent image formed on a photoreceptor with toner of the toner layer to form a toner image;
Circle-equivalent diameter based on the number of toner the toner is measured with a flow type particle image measuring device - in circularity scattergram circle-equivalent number average diameter 2 of the toner - a 10 [mu] m, and an average circularity of 0.950 - at 0.995, a dry one-component toner circularity standard deviation is less than 0.040,
A charge generation layer and a charge transport layer to the power terminal photoreceptor conductive substrate comprising an electrophotographic photosensitive member obtained by laminating in this order, the binder resin of the charge transport layer is a polyarylate resin, the charge Universal hardness HU at an indentation depth of 1 μm from the surface of the transport layer is 248 N / mm ² or more and 254 N / mm ² or less, an elastic deformation rate is 37 % or more and 43.2% or less, and an indentation depth of 5 μm from the surface process cartridge universal hardness HU is 290 N / mm ² or more 305N / mm ² or less in the elastic deformation rate is equal to or less than 38.2% or more 33.9% at. The process cartridge according to claim 4 the weight average molecular weight of polyarylate resin is 200,000 hereinafter 50,000.   The process cartridge according to claim 4, wherein the toner is manufactured using a suspension polymerization method.