JP4407332B2 - Electrophotographic photoreceptor - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member having at least an undercoat layer and a photosensitive layer and having good electrical characteristics and no image defects.

Conventionally, inorganic photoconductive materials such as selenium, selenium-tellurium alloy, arsenic selenide, and cadmium sulfide have been widely used for electrophotographic photoreceptors. However, in recent years, organic materials that have low pollution and are easy to manufacture are used. An electrophotographic photosensitive member using a photoconductive material is used as a photosensitive layer.
As the form of the photosensitive layer, in addition to a so-called dispersion type or single layer type photosensitive layer in which particles of a charge generation material are dispersed in a charge transport medium containing a charge transport material, a charge generation layer containing a charge generation material, A so-called laminated type photosensitive layer in which a charge transport layer containing a charge transport material is laminated is known. In particular, a laminated type photoconductor composed of a charge generation layer and a charge transfer layer which separates the function of absorbing light to generate charges and the function of transporting the generated charges has become the mainstream. These photoreceptors are widely used in fields such as copying machines and laser printers.

The electrophotographic photosensitive member has a basic structure in which a photosensitive layer is formed on a conductive support. It is known to provide an undercoat layer between the photosensitive layer and the support in order to eliminate image defects due to charge injection from the support or defects in the support, to improve adhesion to the photosensitive layer, and to improve chargeability. ing.
As an undercoat layer in which an inorganic material is dispersed in a polyamide resin, titanium oxide and tin oxide, which are metal oxide particles having a band gap of 2 to 4 eV, are dispersed in 8-nylon (for example, see Patent Document 1). A product obtained by dispersing alumina-treated titanium oxide in a polyamide resin (for example, see Patent Document 2) is known. Furthermore, for the purpose of improving the electrical characteristics without disturbing the image characteristics, titanium oxide particles having an average primary particle diameter of 100 nm or less are dispersed in a polyamide resin (for example, see Patent Document 3), and further the environment. In order to improve the characteristics, a material in which metal oxide particles treated with an organosilicon compound are dispersed in a binder resin such as a polyamide resin has been proposed (for example, see Patent Document 4).

On the other hand, one of the roles of the undercoat layer is to conceal defects in the support. To increase this concealment effect, it is known that increasing the thickness of the undercoat layer is effective. It has been. In recent years, with the trend toward miniaturization of electrophotographic apparatuses, an apparatus that employs a contact charging method as a charging method has been increasing. In this charging system apparatus, dielectric breakdown (leakage) of the photoconductor is a problem that causes image defects. It is known that increasing the thickness of the undercoat layer is also effective in suppressing this dielectric breakdown.
Japanese Patent Laid-Open No. 62-280864 Japanese Patent Laid-Open No. 2-181158 Japanese Patent Laid-Open No. 10-069116 JP-A-11-015183

  In order to conceal the defects of the support and to prevent the dielectric breakdown of the photoreceptor, it is desired to increase the thickness of the undercoat layer. However, the electrophotographic photosensitive member having a thick undercoat layer has a drawback that the potential remaining on the photosensitive member is likely to increase due to repeated use. To overcome the problem, for example, An undercoat layer in which titanium oxide particles having an average primary particle diameter of 100 nm or less measured by a transmission electron microscope are dispersed, or an undercoat layer in which metal oxide particles hydrophobized with an organosilicon compound or the like are dispersed. Has been used.

  However, in the undercoat layer in which titanium oxide particles having an average primary particle size of 100 nm or less are dispersed, the electrical characteristics are improved in a normal temperature and normal humidity environment, but the residual potential is likely to increase in a high temperature and high humidity environment. On the other hand, the subbing layer in which metal oxide particles hydrophobized with an organosilicon compound etc. are dispersed has improved characteristics in high temperature and high humidity environments, but low temperature and low humidity. There has been a problem that the electrical characteristics in the environment of are deteriorated.

  In the electrophotographic photoreceptor having at least an undercoat layer and a photosensitive layer, the present invention can be used in all environments from a low temperature and low humidity environment to a high temperature and high humidity environment even when the thickness of the undercoat layer is increased. An object of the present invention is to provide an electrophotographic photosensitive member having an undercoat layer having good electrical characteristics including repeatability. Another object of the present invention is to provide an electrophotographic apparatus provided with a photoreceptor having good electrical characteristics including repetitive characteristics in all environments from a low temperature and low humidity environment to a high temperature and high humidity environment. There is.

The present inventors have found that the above problems can be solved by including conductive metal compound particles in the undercoat layer, and have reached the present invention. That is, the present invention is a conductive substrate, an electrophotographic photosensitive member comprising an undercoat layer and a photosensitive layer containing a metal compound particles and a binder resin, include those wherein the metal compound particles are conductive treatment, conductive The metal compound particles subjected to the chemical conversion treatment are 0.1 to 20% by weight with respect to all the metal compound particles contained in the undercoat layer , and the volume resistivity of the undercoat layer is 1 × 10 ¹⁰ to 1 It exists in the electrophotographic photoreceptor characterized by being × 10 ¹³ Ωcm.

  The electrophotographic photosensitive member having the undercoat layer containing the conductive compound compound particles of the present invention is not affected by defects of the support, prevents dielectric breakdown, and is excellent in various environments. Show properties.

Hereinafter, embodiments of the present invention will be described in detail. However, the description of the constituent elements described below is a representative example of the embodiments of the present invention, and is appropriately modified without departing from the spirit of the present invention. can do.
The photoreceptor in the present invention has an undercoat layer on a conductive substrate, and the undercoat layer contains metal compound particles subjected to a conductive treatment. The undercoat layer is formed between the conductive support and the photosensitive layer.

  The undercoat layer may be formed by a conventional method. That is, it is formed by dissolving or dispersing the material contained in the layer in a solvent, and coating and drying the obtained coating solution on a conductive support. In the coating solution, particles other than metal oxides, charge transport molecules, antioxidants, dispersants, leveling agents, as necessary, as long as the properties of the undercoat layer and the dispersion stability of the coating solution are not deteriorated. Other additives may be added.

The undercoat layer may be applied by any application method as long as it can be applied uniformly to some extent, but is generally applied by dip coating, spray coating, nozzle coating, or the like.
<Conductive treated metal compound particles>
Conductive treatment methods for metal compound particles include carbon black, graphite, gold, silver, palladium, platinum, copper, nickel, aluminum and other metal powders or metal flakes, carbon fibers, metalized glass fibers, stainless steel fibers, aluminum fibers A method of coating the surface of the particles to be conductive with a conductive fiber such as indium oxide, tin oxide, or a transparent conductive filler in which tin oxide is doped with a metal element such as antimony or indium is used. Among these, the use of tin oxide powder doped with a metal element such as antimony or indium is preferable from the viewpoint of easy control of powder resistance.

  Examples of the conductive particles include metal oxides such as titanium oxide, zinc oxide, alumina and silica; metal sulfates such as barium sulfate; metal sulfides such as zinc sulfide; aluminum borate whiskers and the like. Of these, metal oxides such as titanium oxide, zinc oxide, alumina, and silica are preferable. Among these, titanium oxide is particularly preferable because it does not inhibit the cost, dispersibility, and flow of charges generated in the charge generation layer.

  Further, if the average primary particle size of the conductive particles is too large, the dispersion uniformity of the particles is deteriorated. Therefore, the average primary particle size is usually 1 μm or less, preferably 0.5 μm or less. On the other hand, if the particle size is too small, particle aggregation and the like occur, which is not preferable. Examples of the shape of the conductive powder include a spherical shape, a needle shape, a spindle shape, and the like, but the spherical shape is preferred because it is most easily controlled in terms of charging characteristics.

  The powder resistance value of the conductive metal compound particles is not particularly limited, but if it is too small, the change in the volume resistivity of the undercoat layer with respect to the content becomes large, making it difficult to produce the photoreceptor. An 8 MPa compact, usually 1 Ωcm or more, preferably 3 Ωcm or more, more preferably 5 Ωcm or more is used. Also, if the powder resistance value of the conductive oxide particles becomes too large, it is necessary to contain a large amount of particles in order to adjust the volume resistivity of the undercoat layer to a desired value. Therefore, a 9.8 MPa green compact, usually 100 Ωcm or less, preferably 50 Ωcm or less, more preferably 30 Ωcm or less is used.

  In the present invention, since the amount of the conductive oxide particles contained in the undercoat layer is related to the powder resistance value of the conductive oxide particles used, the volume resistivity of the undercoat layer is Although it adjusts suitably in order to make it a desired thing, 0.1 to 20 weight% is preferable normally with respect to all the particles in an undercoat layer, Most preferably, it is 1 to 15 weight%, More preferably, it is 2 to 10 weight% % Range.

Further, one kind of conductive oxide particles may be used, or a mixture of two or more kinds may be used. However, in the case of a mixture of two or more kinds, there is a possibility that particles are aggregated or charge traps are generated.
<Metal oxide particles not subjected to conductive treatment>
The undercoat layer in the present invention preferably contains metal oxide particles that have not been subjected to a conductive treatment, separately from the metal compound particles that have been subjected to a conductive treatment. The metal oxide particles are preferably n-type (electron transporting) particles. Specific examples of such metal oxides include titanates such as strontium titanate, calcium titanate and barium titanate; titanium oxides; metal oxides such as titanium oxide, nickel oxide, zinc oxide and cobalt oxide. And those obtained by doping titanium oxide with metal elements such as niobium, antimony, tungsten, indium, nickel, iron, and silicon. Among these, titanium oxide particles are preferable from the viewpoint of price and stability as a compound.

These metal oxide particles are particles having an average primary particle size of usually 100 nm or less, preferably 60 nm, from the viewpoint of dispersion stability of the coating liquid for forming the undercoat layer and electric characteristics such as residual potential. Hereinafter, those having a thickness of 50 nm or less, usually 10 nm or more, and preferably 20 nm or more are used.
In order to stabilize the dispersion liquid in which the particles are dispersed in the coating liquid for forming the undercoat layer, the metal oxide particles are preferably subjected to a hydrophobic treatment. The hydrophobizing method is not particularly limited as long as it can be hydrophobized, but saturated aliphatic carboxylic acids such as octadecanoic acid and dodecanoic acid; polyols such as 1,1,1-trimethylolethane and pentaerythritol; Examples thereof include a coupling agent, an aluminum-based coupling agent, and a treatment with an organometallic compound such as silicone. Of these, silicone oil such as dimethylpolysiloxane or methylhydrogenpolysiloxane; treatment with a silane treating agent such as methyldimethoxysilane and an organosilicon compound such as a silane coupling agent is preferred. It is preferable to treat with a silane treating agent represented by the structure of the general formula because of good reactivity with metal oxides.

(In the formula, R ¹ and R ² each independently represent a methyl group or an ethyl group. R ³ represents a group selected from the group consisting of a methyl group, an ethyl group, a methoxy group, and an ethoxy group.)
The outermost surface of these hydrophobized particles is treated with the hydrophobizing agent, but before that, it may be treated with a hydrophilic treating agent such as aluminum oxide.
<Binder resin for undercoat layer>
As the binder resin for forming the undercoat layer, a resin material such as polyvinyl acetal, polyamide resin, phenol resin, polyester resin, epoxy resin, polyurethane resin, polyacrylic acid resin, or conductive resin is used for the purpose of improving electrical characteristics. I can do it.

  Among these, a polyamide resin having excellent adhesion to the support and low solubility in the solvent used for the charge generation layer coating solution is preferable. Among them, a copolymerized polyamide resin having a diamine component represented by the following general formula as a constituent component is particularly preferable.

(A and B each independently represent a cyclohexyl ring which may have a substituent, and R ⁴ and R ⁵ each independently represent hydrogen, an alkyl group, an alkoxy group or an aryl group.)
The ratio of the particles to the binder resin can be arbitrarily selected, but from the viewpoint of the stability and characteristics of the coating solution, the range of 0.5 to 6 parts by weight is preferable with respect to 1 part by weight of the binder resin, and 2 parts by weight. A range of 4 parts by weight to 4 parts by weight is particularly preferred.

  If the film thickness of the undercoat layer is too thin, the effect on local charging failure will not be sufficient, and conversely if it is too thick, the residual potential will increase or the adhesive strength between the conductive substrate and the photosensitive layer will decrease. Cause. The thickness of the undercoat layer of the present invention is usually 0.1 μm or more, preferably 1 μm or more, more preferably 3 μm or more, particularly preferably 5 μm or more, usually 20 μm or less, preferably 15 μm or less, more preferably 10 μm. Used in:

If the volume resistivity of the undercoat layer is too low, the charge easily moves and the photoreceptor is not charged. Therefore, it is preferably used at 1 × 10 ¹⁰ Ωcm or more. If the volume resistivity is too high, the residual potential is reduced. Since it leads to accumulation, it is preferably used at 1 × 10 ¹³ Ωcm or less.
<Support>
As the conductive support used in the present invention, any conductive support that is employed in known electrophotographic photosensitive members can be used. Specifically, for example, drums, sheets made of metal materials such as aluminum, stainless steel, copper, nickel, etc., laminates or vapor depositions of these metal foils, or aluminum, copper, palladium, tin oxide, indium oxide on the surface, etc. Insulating supports such as polyester film and paper provided with a conductive layer. Furthermore, a plastic film, a plastic drum, paper, a paper tube, and the like obtained by applying a conductive material such as metal powder, carbon black, copper iodide, and a polymer electrolyte together with an appropriate binder to conduct a conductive treatment may be used. Further, a plastic sheet or drum containing a conductive material such as metal powder, carbon black, or carbon fiber and becoming conductive can be used. Examples thereof include a plastic film and a belt subjected to conductive treatment with a conductive metal oxide such as tin oxide and indium oxide.

Among these, an endless pipe made of metal such as aluminum is a preferable support. An endless pipe made of aluminum or its alloy is formed by processing such as extrusion, drawing, and ironing. What was shape | molded may be used as it is, and what added processes, such as cutting, grinding, and grinding | polishing further, may be used. The surface of the conductive support can be subjected to various treatments such as oxidation treatment and chemical treatment within a range that does not affect the image quality.
<Photosensitive layer>
A photosensitive layer is formed on the undercoat layer. The photosensitive layer may have a single layer structure including a charge generation material, a charge transport material, and a binder resin in a single layer (hereinafter sometimes referred to as a single layer type photosensitive layer or a dispersion type photosensitive layer). Alternatively, a stacked structure in which a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material are stacked (hereinafter also referred to as a stacked photosensitive layer) may be used.

When the photosensitive layer has a single-layer structure, a known material in which a photosensitive material is dispersed in a binder is used. For example, a charge generating material as a main component dispersed in a binder resin. A material in which a charge generation material and a charge transport material are the main components and dispersed in a binder resin is used. In a photosensitive layer having a laminated structure, a charge generation layer and a charge transport layer are laminated on the undercoat layer.
<Charge generating material>
As the charge generating substance, various organic pigments and dyes such as phthalocyanine, azo, perylene, quinacridone, polycyclic quinone, pyrylium salt, indigo, thioindigo, anthanthrone, pyranthrone, and cyanine can be used. Metal-free phthalocyanines, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, and other metals, or phthalocyanines coordinated with oxides, hydroxides, and chlorides, monoazo, bisazo, trisazo, polyazos An azo pigment such as azo pigment and a perylene pigment are preferred.

  Among these charge generation materials, metal-free and metal-containing phthalocyanines can obtain a photosensitive member having a high sensitivity to a laser beam or LED having a relatively long wavelength of 500 nm to 800 nm. Azo pigments such as monoazo, bisazo, and trisazo are preferred because they are excellent in that they have sufficient sensitivity to white light, laser light having a relatively short wavelength of 300 nm to 500 nm, LED, or the like.

Among the phthalocyanines, so-called D-type oxytitanium phthalocyanine, in which the black angle (2θ ± 0.2 °) of the X-ray diffraction spectrum with respect to CuKα characteristic X-ray shows a main diffraction peak at 27.3 °, 9. The so-called A-type oxytitanium phthalocyanine, 9.2, 14.1, 15.3, 19.7, 27.1 showing the main diffraction peaks at 3 °, 13.2 °, 26.2 ° and 27.1 °. Dihydroxysilicon phthalocyanine with main diffraction peaks at °, main diffraction peaks at 8.5 °, 12.2 °, 13.8 °, 16.9 °, 22.4 °, 28.4 ° and 30.1 ° Dichlorotin phthalocyanine, 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 ° and 28.3
Preferred are hydroxygallium phthalocyanine, which shows the main diffraction peak at °, and chlorogallium phthalocyanine, which shows the diffraction peaks at 7.4 °, 16.6 °, 25.5 ° and 28.3 °.

The charge generation layer of the multilayer photosensitive layer can be obtained by coating and drying a coating solution obtained by dissolving or dispersing fine particles of these substances and a binder polymer in a solvent.
Examples of the binder resin used in the charge generation layer include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylic acid ester, methacrylic acid ester, vinyl alcohol, and ethyl vinyl ether, polyvinyl acetal, polycarbonate, polyester, Examples thereof include polyamide, polyurethane, cellulose ether, phenoxy resin, silicon resin, and epoxy resin. As the binder resin, only one kind of these resins may be used, or a mixture of two or more kinds may be used. Among these resins, a polyvinyl acetal resin and a phenoxy resin are preferable because of the dispersion stability of the pigment.

  Solvents used in the coating solution for forming the charge generation layer include alcohols such as methanol and propanol, ethers such as 1,4-dioxane and 1,2-dimethoxyethane, methyl ethyl ketone, cyclohexanone, 4-methoxy-4- Examples include ketones such as methylpentanone-2 and hydrocarbons such as toluene. Only one of these solvents may be used, or a mixture of two or more may be used. Among these solvents, 1,2-dimethoxyethane and 4-methoxy-4-methylpentanone-2 are preferable because of the crystal stability of the pigment.

The ratio of the charge generating material to the binder polymer is not particularly limited, but generally 5 to 500 parts by weight, preferably 20 to 300 parts by weight of the binder polymer is used with respect to 100 parts by weight of the charge generating material.
The charge generation layer may be a vapor deposition film of the charge generation material.
The thickness of the charge generation layer is 0.05 to 5 μm, preferably 0.1 to 2 μm.
<Charge transport material>
As the charge transport material, high molecular compounds such as polyvinyl carbazole, polyvinyl pyrene, polyacenaphthylene, or low molecular weight compounds such as various pyrazoline derivatives, oxazole derivatives, hydrazone derivatives, stilbene derivatives, butadiene derivatives, arylamine derivatives can be used. Today, low molecular weight compounds such as hydrazone derivatives, stilbene derivatives, butadiene derivatives, and hydrazone derivatives are preferably used.

  The charge transport layer in the multilayer photosensitive layer can be obtained by coating and drying a coating solution obtained by dissolving these charge transport materials and binder polymer in a solvent. The binder polymer is preferably a polymer that has good compatibility with the charge transport material and does not crystallize or phase-separate after formation of the coating film. Examples thereof include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylic acid esters, methacrylic acid esters, vinyl alcohol, ethyl vinyl ether, polyvinyl acetals, polycarbonates, polyesters, polysulfones, polyphenylene oxides. , Polyurethane, cellulose ester, cellulose ether, phenoxy resin, silicon resin, epoxy resin, and polymers obtained by introducing the above-described low-molecular compound charge transfer materials into the main chain and / or side chain.

Among these, a polycarbonate resin is preferably used in terms of mechanical properties such as wear resistance and compatibility of the charge transport material and the binder polymer in the solution.
The ratio of the binder resin to the charge transporting material is usually 10 parts by weight or more, preferably 20 parts by weight or more, particularly preferably 30 parts by weight because the electrical characteristics deteriorate if the amount of the charge transporting material is too small relative to the binder resin. Used in more than part. Further, if the amount of the charge transport material is too much, the hardness of the charge transport layer decreases, wear during use increases, and the surface is easily damaged and image defects are liable to occur. Therefore, usually 200 parts by weight or less, preferably 100 parts by weight. Or less, particularly preferably 70 parts by weight or less.

The thickness of the charge transport layer is usually 10 to 50 μm, preferably 13 to 35 μm.
You may add an electron withdrawing compound to a charge transport layer as needed. Electron-withdrawing compounds include tetracyanoquinodimethane, dicyanoquinomethane, cyano compounds such as aromatic esters having a dicyanoquinovinyl group, condensation of nitro compounds such as 2,4,6-trinitrofluorenone, and perylene. Polycyclic aromatic compounds, diphenoquinone derivatives, quinones, aldehydes, ketones, esters, acid anhydrides, phthalides, substituted and unsubstituted salicylic acid metal complexes, substituted and unsubstituted salicylic acid metal salts, aromatic carboxylic acids And metal salts of aromatic carboxylic acids. Preferably, cyano compounds, nitro compounds, condensed polycyclic aromatic compounds, diphenoquinone derivatives, metal complexes of substituted and unsubstituted salicylic acids, metal salts of substituted and unsubstituted salicylic acids, metal complexes of aromatic carboxylic acids, aromatic carboxylic acids A metal salt is preferably used.

The photosensitive layer of the electrophotographic photoreceptor of the present invention has a film forming property, flexibility, coating property, mechanical strength, slipperiness, plasticizer, antioxidant, etc. in order to improve gas resistance properties such as ozone and NOx, You may contain various additives, such as a ultraviolet absorber, an inorganic particle, a resin particle, a wax, a silicone oil, and a leveling agent.
In the single-layer type photosensitive layer, a material obtained by mixing and dispersing the charge generation material, the charge transport material, various additives and a binder polymer is used.
<Other functional layers>
An overcoat layer may be used on the photosensitive layer in order to improve mechanical properties and gas resistant properties such as ozone and NOx. Furthermore, you may have an adhesive layer, an intermediate | middle layer, a transparent insulating layer, etc. as needed.

Furthermore, an intermediate layer may be provided between the undercoat layer and the photosensitive layer, or between the undercoat layer and the conductive substrate. However, the undercoat layer of the present invention alone has an electrical property during repetition. In addition, since good electrical characteristics are exhibited, it is preferable in terms of productivity and cost that such an intermediate layer is not provided.
<Layer formation method>
The undercoat layer, photosensitive layer and other functional layers are formed by applying a coating solution on a conductive support by a spray method, a spiral method, a ring method, a dipping method or the like.

Examples of the spray used in the spray method include air spray, airless spray, electrostatic air spray, electrostatic airless spray, rotary atomizing electrostatic spray, hot spray, and hot airless spray. In order to make the film thickness uniform, a method using a rotary atomizing electrostatic spray described in Republished Hei 1-805198 is preferable.
Examples of the spiral method include a method using an injection coating machine or a curtain coating machine described in Japanese Patent Laid-Open No. 52-119651, and a method in which a paint is streaked from a minute opening described in Japanese Patent Laid-Open No. 1-2231966. And a method using a multi-nozzle body disclosed in JP-A-3-193161.
<Image forming apparatus>
Next, an embodiment of an image forming apparatus using the electrophotographic photosensitive member of the present invention (an image forming apparatus of the present invention) will be described with reference to FIG. However, the embodiment is not limited to the following description, and can be arbitrarily modified without departing from the gist of the present invention.

As shown in FIG. 1, the image forming apparatus includes an electrophotographic photosensitive member 1, a charging device 2, an exposure device 3, and a developing device 4, and further, a transfer device 5, a cleaning device 6 and a fixing device as necessary. A device 7 is provided.
The electrophotographic photoreceptor 1 is not particularly limited as long as it is the above-described electrophotographic photoreceptor of the present invention, but in FIG. 1, as an example, a drum in which the above-described photosensitive layer is formed on the surface of a cylindrical conductive support. The photoconductor is shown. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5 and a cleaning device 6 are arranged along the outer peripheral surface of the electrophotographic photosensitive member 1.

  The charging device 2 charges the electrophotographic photosensitive member 1 and uniformly charges the surface of the electrophotographic photosensitive member 1 to a predetermined potential. Examples of the charging device include a corona charging device such as corotron and scorotron, a direct charging device (contact type charging device) for charging a charged member by bringing a direct charging member to which a voltage is applied into contact with the surface of the photoreceptor, and a contact type charging device such as a charging brush. Often used. Examples of direct charging means include contact chargers such as charging rollers and charging brushes. In FIG. 1, a roller-type charging device (charging roller) is shown as an example of the charging device 2. As the direct charging means, either charging with air discharge or injection charging without air discharge is possible. Moreover, as a voltage applied at the time of charging, it is possible to use only a direct current voltage or to superimpose alternating current on direct current.

  The type of the exposure apparatus 3 is not particularly limited as long as it can expose the electrophotographic photoreceptor 1 to form an electrostatic latent image on the photosensitive surface of the electrophotographic photoreceptor 1. Specific examples include halogen lamps, fluorescent lamps, lasers such as semiconductor lasers and He—Ne lasers, LEDs, and the like. Further, exposure may be performed by a photoreceptor internal exposure method. The light used for the exposure is arbitrary. For example, the exposure may be performed using monochromatic light with a wavelength of 780 nm, monochromatic light with a wavelength slightly shorter than 600 nm to 700 nm, or monochromatic light with a short wavelength of 380 nm to 500 nm. .

  The type of the developing device 4 is not particularly limited, and an arbitrary device such as a dry development method such as cascade development, one-component insulating toner development, one-component conductive toner development, or two-component magnetic brush development, or a wet development method is used. be able to. In FIG. 1, the developing device 4 includes a developing tank 41, an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45, and has a configuration in which toner T is stored inside the developing tank 41. . Further, a replenishing device (not shown) for replenishing the toner T may be attached to the developing device 4 as necessary. The replenishing device is configured to be able to replenish toner T from a container such as a bottle or a cartridge.

The supply roller 43 is formed from a conductive sponge or the like. The developing roller 44 is made of a metal roll such as iron, stainless steel, aluminum, or nickel, or a resin roll obtained by coating such a metal roll with a silicon resin, a urethane resin, a fluorine resin, or the like. The surface of the developing roller 44 may be smoothed or roughened as necessary.
The developing roller 44 is disposed between the electrophotographic photoreceptor 1 and the supply roller 43 and is in contact with the electrophotographic photoreceptor 1 and the supply roller 43, respectively. The supply roller 43 and the developing roller 44 are rotated by a rotation drive mechanism (not shown). The supply roller 43 carries the stored toner T and supplies it to the developing roller 44. The developing roller 44 carries the toner T supplied by the supply roller 43 and contacts the surface of the electrophotographic photosensitive member 1.

  The restricting member 45 is formed of a resin blade such as silicon resin or urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating such a metal blade with resin. The regulating member 45 contacts the developing roller 44 and is pressed against the developing roller 44 side with a predetermined force by a spring or the like (a general blade linear pressure is 5 to 500 g / cm). If necessary, the regulating member 45 may be provided with a function of imparting charging to the toner T by frictional charging with the toner T.

The agitator 42 is rotated by a rotation driving mechanism, and agitates the toner T and conveys the toner T to the supply roller 43 side. A plurality of agitators 42 may be provided with different blade shapes and sizes.
The type of the transfer device 5 is not particularly limited, and an apparatus using an arbitrary system such as an electrostatic transfer method such as corona transfer, roller transfer, or belt transfer, a pressure transfer method, or an adhesive transfer method can be used. . Here, it is assumed that the transfer device 5 includes a transfer charger, a transfer roller, a transfer belt, and the like that are disposed to face the electrophotographic photoreceptor 1. The transfer device 5 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charging potential of the toner T, and transfers the toner image formed on the electrophotographic photosensitive member 1 to a recording paper (paper, medium) P. Is.

  There is no restriction | limiting in particular about the cleaning apparatus 6, Arbitrary cleaning apparatuses, such as a brush cleaner, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, can be used. The cleaning device 6 is for scraping off residual toner adhering to the photoreceptor 1 with a cleaning member and collecting the residual toner. However, when there is little or almost no toner remaining on the surface of the photoreceptor, the cleaning device 6 may be omitted.

  The fixing device 7 includes an upper fixing member (fixing roller) 71 and a lower fixing member (fixing roller) 72, and a heating device 73 is provided inside the fixing member 71 or 72. FIG. 1 shows an example in which a heating device 73 is provided inside the upper fixing member 71. As the upper and lower fixing members 71 and 72, known heat fixing members such as a fixing roll in which a metal base tube such as stainless steel or aluminum is coated with silicon rubber, a fixing roll coated with a fluororesin, or a fixing sheet are used. be able to. Further, the fixing members 71 and 72 may be configured to supply a release agent such as silicone oil in order to improve the releasability, or may be configured to forcibly apply pressure to each other by a spring or the like.

When the toner transferred onto the recording paper P passes between the upper fixing member 71 and the lower fixing member 72 heated to a predetermined temperature, the toner is heated to a molten state and cooled after passing through the recording paper. Toner is fixed on P.
The type of the fixing device is not particularly limited, and a fixing device of any type such as heat roller fixing, flash fixing, oven fixing, pressure fixing, etc. can be provided including those used here.

In the electrophotographic apparatus configured as described above, an image is recorded as follows. That is, first, the surface (photosensitive surface) of the photoreceptor 1 is charged to a predetermined potential (for example, −600 V) by the charging device 2. At this time, charging may be performed by a DC voltage, or charging may be performed by superimposing an AC voltage on the DC voltage.
Subsequently, the photosensitive surface of the charged photoreceptor 1 is exposed by the exposure device 3 according to the image to be recorded, and an electrostatic latent image is formed on the photosensitive surface. The developing device 4 develops the electrostatic latent image formed on the photosensitive surface of the photoreceptor 1.

The developing device 4 thins the toner T supplied by the supply roller 43 with a regulating member (developing blade) 45 and has a predetermined polarity (here, the same polarity as the charging potential of the photosensitive member 1) and the negative polarity. ), And conveyed while being carried on the developing roller 44 to be brought into contact with the surface of the photoreceptor 1.
When the charged toner T carried on the developing roller 44 comes into contact with the surface of the photoreceptor 1, a toner image corresponding to the electrostatic latent image is formed on the photosensitive surface of the photoreceptor 1. This toner image is transferred onto the recording paper P by the transfer device 5. Thereafter, the toner remaining on the photosensitive surface of the photoreceptor 1 without being transferred is removed by the cleaning device 6.

After the transfer of the toner image onto the recording paper P, the final image is obtained by passing the fixing device 7 and thermally fixing the toner image onto the recording paper P.
In addition to the above-described configuration, the image forming apparatus may have a configuration capable of performing, for example, a static elimination process. The neutralization step is a step of neutralizing the electrophotographic photosensitive member by exposing the electrophotographic photosensitive member, and a fluorescent lamp, an LED, or the like is used as the neutralizing device. In addition, the light used in the static elimination process is often light having an exposure energy that is at least three times that of the exposure light.

The image forming apparatus may be further modified. For example, the image forming apparatus may be configured to perform a pre-exposure process, an auxiliary charging process, or the like, or may be configured to perform offset printing. A full-color tandem system configuration using toner may be used.
The electrophotographic photosensitive member 1 is combined with one or more of the charging device 2, the exposure device 3, the developing device 4, the transfer device 5, the cleaning device 6, and the fixing device 7 to form an integrated cartridge ( The electrophotographic photosensitive member cartridge may be configured to be detachable from a main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. In this case, for example, when the electrophotographic photosensitive member 1 and other members are deteriorated, the electrophotographic photosensitive member cartridge is removed from the main body of the image forming apparatus, and another new electrophotographic photosensitive member cartridge is mounted on the main body of the image forming apparatus. This facilitates maintenance and management of the image forming apparatus.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these, unless the summary is exceeded. In the examples, “parts” means “parts by weight” unless otherwise specified.
<Production Method of Dispersion S1>
After drying a slurry obtained by mixing rutile type titanium oxide having an average primary particle diameter of 40 nm (product name: TTO55N, manufactured by Ishihara Sangyo Co., Ltd.) and 3% by weight of methyldimethoxysilane with the titanium oxide in a ball mill. Further, the hydrophobized titanium oxide obtained by washing with methanol and drying was subjected to ball mill dispersion in a methanol / 1-propanol mixed solvent to obtain a hydrophobized titanium oxide dispersion slurry.

  The dispersion slurry obtained here and methanol, 1-propanol, toluene, and nylon pellets represented by the following structural formula are stirred and mixed while heating, the nylon pellets are dissolved, and then ultrasonic dispersion treatment is performed. Finally, a dispersion liquid of hydrophobized titanium oxide / nylon = 4/1 was prepared, and this was designated as dispersion liquid S1.

<Production Method of Dispersion S2>
The hydrophobized titanium oxide obtained in the same manner as in the preparation of the dispersion S1 was ball milled in a methanol / 1-propanol mixed solvent to obtain a hydrophobized titanium oxide dispersion slurry. Similarly, an anatase-type titanium oxide (product name EC-100, manufactured by Titanium Industry Co., Ltd.) having an average particle size of 0.3 to 0.4 μm, which has been subjected to a conductive treatment with conductive antimony-doped tin oxide. A dispersion slurry was prepared.

Mixing the two obtained dispersion slurries, further stirring and mixing the same nylon pellets used in the preparation of methanol, 1-propanol, toluene, dispersion S1 to dissolve the nylon pellets, Thereafter, ultrasonic dispersion treatment was performed to finally prepare a dispersion liquid of hydrophobized titanium oxide / EC-100 / nylon = 99/1/25, and this was designated as dispersion liquid S2.
<Method for producing coating liquid S3>
A dispersion similar to the coating liquid S2 was prepared except that the ratio of hydrophobized titanium oxide / EC-100 / nylon was changed to hydrophobized titanium oxide / EC-100 / nylon = 95/5/25. S3.
<Method for producing coating liquid S4>
A dispersion similar to the coating liquid S2 was prepared except that the ratio of hydrophobized titanium oxide / EC-100 / nylon was changed to hydrophobized titanium oxide / EC-100 / nylon = 90/10/25. S4.
<Method for producing coating solution S5>
A dispersion similar to the coating liquid S2 was prepared except that the ratio of hydrophobized titanium oxide / EC-100 / nylon was changed to hydrophobized titanium oxide / EC-100 / nylon = 85/15 / 33.3. Dispersion S5 was obtained.
<Method for producing coating liquid S6>
A dispersion similar to the coating liquid S2 was prepared except that the ratio of hydrophobized titanium oxide / EC-100 / nylon was changed to hydrophobized titanium oxide / EC-100 / nylon = 75/25/50. S6.
<Example 1>
Dispersion S2 was used to dip and apply to an aluminum cylinder having an outer diameter of 30 mm, a length of 250 mm, and a thickness of 1.0 mm, and an undercoat layer was provided so that the dry film thickness was 6 μm.
Next, the black angle (2θ ± 0.2 °) of the X-ray diffraction spectrum with respect to the CuKα characteristic X-ray shows main peaks at 9.3 °, 13.2 °, 26.2 °, and 27.1 °, Add 500 parts of 1,2-dimethoxyethane to 10 parts of A-type oxytitanium phthalocyanine and 5 parts of polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name # 6000-C), and grind and disperse with a sand grind mill Went. An aluminum cylinder provided with an undercoat layer in advance was dip coated on this dispersion, and a charge generation layer was provided so that the dry film thickness was 0.3 g / m ² (about 0.3 μm).

  Next, 100 parts of a polycarbonate resin having the following structure (monomer molar ratio, m: n = 7: 3)

50 parts of a hydrazone compound represented by the following structural formula

14 parts of a hydrazone compound represented by the following structural formula

2 parts of cyano compound represented by the following structural formula

A charge transfer layer was formed by dip-coating a solution obtained by dissolving the compound in a mixed solvent of 1,4 dioxane and tetrahydrofuran so that the film thickness after drying was 17.5 μm. The drum thus obtained is referred to as a photoreceptor A1.
<Example 2>
A photoconductor was prepared in the same manner as in Example 1 except that the aluminum cylinder used in Example 1 was provided with an undercoat layer using a dispersion S3 so that the dry film thickness was 6 μm by dip coating. Obtained. The drum thus obtained is designated as a photoreceptor A2.
<Example 3>
A photoconductor was prepared in the same manner as in Example 1 except that the aluminum cylinder used in Example 1 was provided with an undercoating layer using a dispersion S4 so that the dry film thickness was 6 μm by dip coating. Obtained. The drum thus obtained is designated as a photoreceptor A3.
<Example 4>
A photoconductor was prepared in the same manner as in Example 1 except that the aluminum cylinder used in Example 1 was provided with an undercoating layer so that the dry film thickness was 6 μm by dip coating using Dispersion S5. Obtained. The drum thus obtained is designated as a photoreceptor A4.
<Comparative Example 1>
The photoconductor was prepared in the same manner as in Example 1 except that the aluminum cylinder used in Example 1 was provided with an undercoat layer using a dispersion S1 so that the dry film thickness was 6 μm by dip coating. Obtained. The drum thus obtained is used as a comparative photoreceptor B1.
<Comparative example 2>
A photoconductor was prepared in the same manner as in Example 1 except that the aluminum cylinder used in Example 1 was provided with an undercoating layer using a dispersion S6 so that the dry film thickness was 6 μm by dip coating. Obtained. The drum thus obtained is used as a comparative photoreceptor B2.

The volume resistivity of the undercoat layer was obtained by applying the undercoat layer coating solutions S1 to S6 with a wire bar so that the film thickness after drying was 6 μm on the aluminum deposited layer deposited on the polyester film. It was carried out using the volume resistivity measurement data obtained by drying. These samples were measured using a high resistivity meter (trade name Hirestar-UP MCP-HT450 manufactured by Mitsubishi Chemical Corporation), and the value calculated from the resistance value after 1 minute was taken as the measured value, and the volume resistivity value was Obtained. The results are shown in Table 1.

実施例１〜４の感光体に用いた下引き層の体積抵抗率は、１×１０¹⁰〜１×１０¹³Ωｃｍの範囲であり、導電化処理された金属化合物粒子を含まない比較例１では体積抵抗率が１×１０¹³Ωｃｍを超え、導電化処理された金属化合物粒子を２５重量％含む比較例２では、体積抵抗率が１×１０¹⁰Ωｃｍ以下であった。
＜評価＞
次にこれらの電子写真感光体を感光体特性測定機に装着して、気温５℃、相対湿度１０％（以下、これをＬＬ環境ということがある）、気温２５℃、相対湿度５０％（以下、これをＮＮ環境ということがある）、気温３５℃、相対湿度８５％（以下、これをＨＨ環境ということがある）の各環境下で、表面電位が−６００Ｖになるように感光体を帯電させた後、７８０ｎｍの光を照射した時の表面電位が１／２になるのに要する露光量（以下、半減露光量またはＥ１／２ということがある）、表面電位を−６００Ｖになるように感光体を帯電させ５秒間放置したときの、帯電時と５秒放置後の電位の比（以下、ＤＤＲということがある）、６６０ｎｍのＬＥＤ光を照射した後の残留電位（以下、Ｖｒということがある）を測定した。結果を表２に示す。

The volume resistivity of the undercoat layer used in the photoreceptors of Examples 1 to 4 is in the range of 1 × 10 ¹⁰ to 1 × 10 ¹³ Ωcm, and in Comparative Example 1 that does not include conductive metal compound particles. In Comparative Example 2 in which the volume resistivity exceeded 1 × 10 ¹³ Ωcm and the conductive metal compound particles contained 25% by weight, the volume resistivity was 1 × 10 ¹⁰ Ωcm or less.
<Evaluation>
Next, these electrophotographic photoreceptors are mounted on a photoreceptor characteristic measuring machine, and the temperature is 5 ° C., the relative humidity is 10% (hereinafter sometimes referred to as LL environment), the temperature is 25 ° C., and the relative humidity is 50% (hereinafter referred to as “L”). The photosensitive member is charged so that the surface potential becomes −600 V under each environment of an ambient temperature of 35 ° C. and a relative humidity of 85% (hereinafter sometimes referred to as an HH environment). After that, the exposure amount required to halve the surface potential when irradiated with light of 780 nm (hereinafter sometimes referred to as half exposure amount or E1 / 2), and the surface potential to be −600V When the photoreceptor is charged and left for 5 seconds, the ratio of the potential after charging to 5 seconds (hereinafter sometimes referred to as DDR), the residual potential after irradiation with 660 nm LED light (hereinafter referred to as Vr) Measured). The results are shown in Table 2.

感光体Ａ１，Ａ２，Ａ３，Ａ４は、ＬＬ，ＮＮ，ＨＨの各環境下において、良好な電気特性を示すが、比較感光体Ｂ１は、特にＬＬ環境下において、６６０ｎｍのＬＥＤ光照射後の残留電位が大きくなり良好でない。また、比較感光体B2は、表面電位−６００Ｖまで帯電せず、電気特性を測定することができなかった。

The photoconductors A1, A2, A3, and A4 exhibit good electrical characteristics in each of the LL, NN, and HH environments, but the comparative photoconductor B1 has a residual after 660 nm LED light irradiation, particularly in the LL environment. The potential increases and is not good. Further, the comparative photoreceptor B2 was not charged up to a surface potential of −600 V, and the electrical characteristics could not be measured.

Next, these photoconductors A1 to A4 and the comparative photoconductor B1 are mounted on a commercially available laser printer (LP-1700 manufactured by Seiko Epson Corporation), and 16,000 sheets of A4 paper are printed with a 5% character pattern in an HH environment. After (2000 sheets were printed per day), the exposure was performed with a writing exposure dose (1.5 μJ / cm ² ), and the potential was measured. The results are shown in Table 3. A1, A2, A3
, A4 and B1 were both good with little potential increase compared to the initial stage.

＜比較例３＞
実施例１で用いたアルミニウム製シリンダーに、分散液Ｓ２を用いて、浸漬塗布により、その乾燥膜厚が３μｍとなるように下引き層を設けた以外は、実施例１と同様にして感
光体を得た。このようにして得たドラムを比較感光体Ｂ３とする。

<Comparative Example 3>
A photoconductor in the same manner as in Example 1 except that the aluminum cylinder used in Example 1 was provided with an undercoat layer by dip coating so that the dry film thickness was 3 μm using Dispersion S2. Got. The drum thus obtained is referred to as a comparative photoreceptor B3.

  The photoconductor A1 and the comparative photoconductor B3 are respectively mounted on a commercially available laser printer (LP1900 manufactured by Seiko Epson Corporation) characterized by brush charging to which direct current or alternating current is applied, and a 5% character pattern of A4 paper under NN environment Was output and evaluated for dielectric breakdown. In the photoreceptor A1 with an undercoat layer thickness of 6 μm, dielectric breakdown did not occur even after printing 20000 sheets, but with the photoreceptor B3 with an undercoat layer thickness of 3 μm, dielectric breakdown occurred when 6900 sheets were printed. An image to show appeared. The results are shown in Table 4.

1 is a conceptual diagram illustrating an embodiment of an image forming apparatus using an electrophotographic photosensitive member of the present invention.

Explanation of symbols

1 Photoconductor 2 Charging device (charging roller)
DESCRIPTION OF SYMBOLS 3 Exposure apparatus 4 Developing apparatus 5 Transfer apparatus 6 Cleaning apparatus 7 Fixing apparatus 41 Developing tank 42 Agitator 43 Supply roller 44 Developing roller 45 Control member 71 Upper fixing member (fixing roller)
72 Lower fixing member (fixing roller)
73 Heating device T Toner P Recording paper

Claims (11)

An electrophotographic photosensitive member having an undercoat layer containing a metal compound particle and a binder resin and a photosensitive layer on a conductive substrate, the metal compound particle including the metal compound particle obtained by conducting the conductive treatment, The metal compound particles are 0.1 to 20% by weight with respect to the total metal compound particles contained in the undercoat layer , and the volume resistivity of the undercoat layer is 1 × 10 ¹⁰ to 1 × 10 ^13. An electrophotographic photosensitive member characterized by being Ωcm. 2. The electrophotographic photosensitive member according to claim 1, wherein the undercoat layer contains metal oxide particles not subjected to the conductive treatment in addition to the metal compound particles subjected to the conductive treatment. 3. The electrophotographic photosensitive member according to claim 2 , wherein the metal oxide particles not subjected to the conductive treatment contain titanium atoms as constituent components. The average primary particle diameter of the metal oxide particles which are not conductive treatment, characterized in that at 100nm or less, the electrophotographic photosensitive member according to claim 2 or claim 3. Wherein the film thickness of the undercoat layer is 3μm or more, electrophotographic photosensitive member according to any one of claims 1-4. Undercoat layer is characterized by containing a polyamide resin as a binder resin, electrophotographic photosensitive member according to any one of claims 1 to 5 The charge generating material contained in the photosensitive layer, the electrophotographic photosensitive member according to any one of claims 1 to 6, wherein the phthalocyanine pigment. The ratio of metal compound particles and a binder resin in the undercoat layer, characterized in that the binder resin 1 parts by weight, 6 parts by weight 0.5 parts by weight, more of claims 1 to 7 2. The electrophotographic photosensitive member according to item 1. The electrophotographic photosensitive member according to claim 1, wherein the thickness of the undercoat layer is 20 μm or less. An image forming apparatus using the electrophotographic photosensitive member according to claim 1. An image forming method using the image forming apparatus according to claim 10.

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