JP4942382B2 - Electrophotographic photoreceptor and image forming apparatus using the photoreceptor - Google Patents

Description

  The present invention relates to an electrophotographic photoreceptor having an undercoat layer and a coating film, and more specifically, an electrophotographic photoreceptor having an undercoat layer having good coatability, formed from a coating solution containing a specific substance, And a coating film.

  Conventionally, inorganic photoconductive materials such as selenium, selenium-tellurium alloys, arsenic selenide, and cadmium sulfide have been widely used for electrophotographic photoreceptors. On the other hand, in recent years, research has been actively conducted on the use of organic photoconductive materials, which are low pollution and easy to manufacture, for the photosensitive layer. In particular, a laminated type photoconductor composed of a charge generation layer and a charge transport layer in which the function of absorbing light to generate charges and the function of transporting the generated charges are separated has become mainstream. These photoreceptors are widely used in fields such as copying machines and laser printers.

  An electrophotographic photosensitive member has a basic structure in which a photosensitive layer is formed on a conductive substrate. In order to eliminate image defects due to charge injection from the conductive substrate or defects in the conductive substrate, to improve adhesion to the photosensitive layer, to improve chargeability, etc., the subbing is performed between the photosensitive layer and the conductive substrate. A layer is provided.

  As the undercoat layer, for example, polyvinyl methyl ether, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, ethylene-acrylic acid copolymer, polyamide, casein, gelatin, polyethylene, polyester, phenol resin, vinyl chloride- It is known to use resin materials such as vinyl acetate copolymer, epoxy resin, polyvinyl pyrrolidone, polyvinyl pyridine, polyurethane, polyglutamic acid, and polyacrylic acid. Among these resin materials, a soluble polyamide resin is particularly preferable (see, for example, Patent Documents 1, 2, and 3).

  Furthermore, in order to improve electrical characteristics such as low temperature and low humidity, an undercoat layer is known in which metal oxide particles such as titanium oxide particles are dispersed in a polyamide resin. Further, it is known that the dispersed metal oxide particles treated with an organosilicon compound such as polysiloxane or silane compound can suppress water absorption and improve image characteristics and environmental characteristics. .

  In recent years, a contact charging method in which charging is performed with a charging roll or the like has been widely used in the trend toward miniaturization of electrophotographic apparatuses. In the electrophotographic apparatus of the contact charging method, leakage (dielectric breakdown) of the electrophotographic photosensitive member is likely to occur, so that the undercoat layer is also required to have a role of leakage resistance.

  As one countermeasure against leakage, it is known that thickening the undercoat layer is effective, and it has been demanded to apply the thick undercoat layer with good coatability.

  On the other hand, the undercoat layer generally contains an alcohol-soluble resin. The solvent of the coating solution for producing a coating film (undercoat layer) containing an alcohol-soluble resin is generally an alcohol solvent. Even in an alcohol solvent, the solubility of the resin, the drying of the coating film is performed. 1-propanol, 1-butanol, etc., in order to suppress the solubility (gelation) of the resin, to control the drying time, and to improve the applicability Is generally mixed as the second component.

  However, a coating film coated with an alcohol-soluble resin solution dissolved in a solvent mainly composed of an alcohol solvent as described above has a problem that it is difficult to be uniform and smooth, which causes image defects. In particular, when the thickness of the coating film is increased, the problem becomes large. Further, when inorganic particles are contained, it is likely that the unevenness of the film thickness is significantly increased, and the problem of image defects is further increased. It was.

  The fact that the film thickness unevenness is large means that, for example, even if a film thickness of 5 μm is produced as an average film thickness, the film thickness is only 3 μm in some places and 7 μm in some places, for example. That is. In the case of such a film, for example, even if a thick film is used in order to suppress leakage (dielectric breakdown), electric field concentration occurs where the film thickness is thin, and this portion is liable to leak. The effect of having a thick film is reduced. In addition, when the film thickness unevenness is large, the potential after light irradiation varies depending on the location, and the problem of causing uneven image density is further added.

JP 51-114132 A JP 52-025638 A JP 56-021129 A

  The present invention has been made in view of the above-described background art, and an object thereof is to provide an electrophotographic photosensitive member that does not cause problems of image defects and image density unevenness. Moreover, even if it contains an inorganic compound particle | grain and is a thick film, it is providing a uniform coating film without film thickness nonuniformity.

  As a result of intensive studies to solve the above problems, the present inventor applied a thick film when the undercoat layer of the electrophotographic photosensitive member is formed from a coating solution containing at least a tertiary alcohol. I found it evenly applied. As a result, it has been found that leakage (dielectric breakdown) can be suppressed, and image defects and image density unevenness can be suppressed, and the present invention has been completed.

  That is, the present invention relates to an electrophotographic photosensitive member having at least an undercoat layer containing an alcohol-soluble resin and a photosensitive layer on a conductive substrate, wherein the undercoat layer is coated with at least a tertiary alcohol. The present invention provides an electrophotographic photosensitive member characterized by being formed from a coating solution contained as a solvent.

  The present invention also provides an image forming apparatus characterized in that the charging method of the electrophotographic photosensitive member is a contact charging method and the above-described electrophotographic photosensitive member is used.

  Further, the present invention is a coating film containing at least an alcohol-soluble resin and inorganic compound particles, and the coating film is formed from a coating solution containing at least a tertiary alcohol as a coating solvent. The present invention provides a coating film characterized by that.

  According to the present invention, a coating film such as an undercoat layer containing an alcohol-soluble resin can be uniformly formed even with a thick film without film thickness unevenness. Furthermore, even if it contains inorganic compound particles, it is possible to form a coating film such as an undercoat layer with small film thickness unevenness. As a result, when it is applied to the undercoat layer of an electrophotographic photosensitive member, a leak It is possible to provide an electrophotographic photosensitive member that can suppress (dielectric breakdown) and has good image quality in which problems of image defects and image density unevenness are solved.

  Hereinafter, the present invention will be described, but the present invention is not limited to the following specific embodiments, and can be arbitrarily modified and implemented. Hereinafter, the present invention will be described with respect to an electrophotographic photosensitive member having an undercoat layer, but the present invention also has a similar effect with respect to coating properties even with respect to a general coating film. In addition, a general coating film is also described.

[Conductive substrate]
The electrophotographic photoreceptor of the present invention has at least an undercoat layer containing an alcohol-soluble resin and a photosensitive layer on a conductive substrate. The conductive substrate in the electrophotographic photosensitive member of the present invention is not particularly limited. For example, a substrate made of a metal such as aluminum, an aluminum alloy, stainless steel, copper, or nickel; an insulating substrate such as a polyester film, paper, or glass And a surface obtained by depositing a metal such as aluminum or copper; and a conductive layer in which a conductive material is dispersed in a binder resin. Further, a conductive layer in which a conductive material is dispersed on a metal such as aluminum may be provided. Of these, an endless pipe made of a metal such as aluminum is preferably cut into an appropriate length. In the present invention, a thick tube obtained by extruding an aluminum-based metal and ironed or drawn may be used as it is without being cut.

  The surface of the conductive substrate can be subjected to various treatments such as oxidation treatment and chemical treatment within a range that does not affect the image quality. An anodized film may be formed on the surface of the conductive substrate.

[Underlayer]
The undercoat layer is located between the conductive substrate and all the photosensitive layers (photosensitive layer closest to the conductive substrate), has substantially no charge generating ability, has insulating properties, and charge transport. A layer having a function.

[[Resin in undercoat]]
The electrophotographic photoreceptor of the present invention has an undercoat layer containing at least an alcohol-soluble resin on the conductive substrate. Here, in the present invention, the term “alcohol-soluble resin” refers to a resin that dissolves in methanol at a concentration of at least 3% by mass at any one temperature in the temperature range from 20 ° C. to the boiling point of methanol. Say.

  The alcohol-soluble resin is not particularly limited, but a polyvinyl acetal resin, a polyvinyl alcohol resin, a polyamide resin and the like are preferable, and an alcohol-soluble polyamide resin is particularly preferable in terms of the characteristics of the undercoat layer.

  Alcohol-soluble polyamide resins include a modified type and a copolymer type. Examples of the modified type include Nylon 6 N-methyl modified, Nylon 6 methoxymethyl modified, Nylon 8 N-ethyl modified, Nylon 8 ethoxymethyl modified, etc. Among them, nylon 6 methoxymethyl Modified products are preferred.

  Examples of the copolymer type include copolymers such as 6 nylon, 8 nylon, 11 nylon, 12 nylon, 66 nylon, 610 nylon, 612 nylon, and 620 nylon. Among these, 6/66/11 copolymer nylon, 6 Ternary or quaternary copolymer nylons such as / 66/12 copolymer nylon, 6/66/610 copolymer nylon, and 6/66/610/12 copolymer nylon are preferable.

  As the alcohol-soluble resin, a copolymerized polyamide resin having a diamine compound represented by the following general formula (1) as a repeating unit is also preferred from the viewpoint of image characteristics and coating solution stability. Furthermore, the copolymer nylon described above and having a diamine compound represented by the following general formula (1) as a repeating unit is particularly preferable from the viewpoint of image characteristics and coating solution stability.

［式（１）中、Ａ及びＢは、それぞれ独立して置換基を有していてもよいシクロヘキサン環を表し、Ｒ^４及びＲ^５は、それぞれ独立して水素原子、アルキル基、アルコキシ基又はアリール基を表す。］

[In formula (1), A and B each independently represent a cyclohexane ring which may have a substituent, and R ⁴ and R ⁵ each independently represent a hydrogen atom, an alkyl group, an alkoxy group or Represents an aryl group. ]

In formula (1), A and B each independently represent a cyclohexane ring which may have a substituent, and the substituent for cyclohexane rings A and B is an alkyl group having 1 to 8 carbon atoms. And alkoxy groups. Particularly preferred is a methyl group or an ethyl group. R ⁴ and R ⁵ each independently represents a hydrogen atom, an alkyl group, an alkoxy group or an aryl group. As this alkyl group, a C1-C8 alkyl group is preferable. As this alkoxy group, a C1-C8 alkoxy group is preferable, and a methoxy group or an ethoxy group is especially preferable. As this aryl group, a phenyl group, a naphthyl group, an anthryl group and the like which may have a lower alkyl substituent are preferable.

  Preferred examples of the copolymer polyamide resin that is contained as a repeating unit together with the diamine compound represented by the general formula (1) include the following. That is, examples of the diamine component include alkylene diamines such as butanediamine, hexamethylenediamine, and octamethylenediamine. Examples of the dicarboxylic acid component include succinic acid, adipic acid, butanedicarboxylic acid, hexamethylenedicarboxylic acid, and octamethylene. Examples include alkylene dicarboxylic acids such as dicarboxylic acid, decamethylene dicarboxylic acid, and octadecamethylene dicarboxylic acid. Examples of the component containing an amino group and a carboxyl group in one molecule include amino acids. , Γ-butyrolactam, δ-valerolactam, and ε-caprolactam.

  The number average molecular weight of the alcohol-soluble polyamide resin is not particularly limited, but is preferably in the range of 5,000 to 50,000, and more preferably in the range of 10,000 to 30,000. If the number average molecular weight is too large, it may be difficult to form a coating film having a uniform thickness. If it is too small, it may be difficult to form a coating film having a sufficient thickness.

[[Inorganic compound particles in undercoat layer]]
In the present invention, it is preferable in terms of electrical characteristics that the undercoat layer contains inorganic compound particles. Examples of the inorganic compound particles include oxide particles, nitride particles, and halide particles. In the case of an undercoat layer of an electrophotographic photosensitive member, the inorganic compound particles may be metal oxide particles. This is preferable from the viewpoint of excellent electrical characteristics. Examples of the metal oxide particles include silicon oxide, aluminum oxide, titanium oxide, tin oxide, zinc oxide, iron oxide, nickel oxide, antimony oxide, strontium titanate, calcium titanate, and barium titanate. Of 2 to 4 eV is preferable, and among these, titanium oxide or zinc oxide is particularly preferable.

  The crystal form of titanium oxide includes rutile, anatase, brookite, and amorphous, and any crystal form can be used, but the rutile form is preferred.

  In addition, it is preferable that the metal oxide particles are surface-treated with an organosilicon compound in terms of environmental characteristics such as long-run live-action characteristics under high temperature and high humidity. The organosilicon compound is not particularly limited as long as it is effective for surface treatment, but polysiloxane compounds such as methylhydrogenpolysiloxane and polymethoxysiloxane; methyldimethoxysilane, dimethyldimethoxysilane, methyldiethoxysilane, dimethyldichlorosilane Silane compounds such as ethyltrichlorosilane; 1-trifluoro-2-difluoro-3-difluoro-4-difluoro-5-difluoro-6-difluorooctyltrimethoxysilane, 1-trifluoro-2-difluoro-3-difluoro Preferred examples include fluoroalkylsilane compounds such as -4-difluoro-5-difluoro-6-difluoro-7-difluoro-8-difluorodecatitrimethoxysilane. Among these, surface treatment with methylhydrogenpolysiloxane, methyldimethoxysilane, or fluoroalkylsilane compound is particularly preferable from the viewpoint of good reactivity with metal oxide particles. Further, titanium oxide surface-treated with the above organosilicon compound is preferable in terms of good environmental characteristics.

  The particle diameter of the inorganic compound particles is preferably a volume average primary particle diameter of 100 nm or less, particularly preferably 10 nm or more and 60 nm or less, in view of the stability of the coating liquid, electrical characteristics and the like. When the particle diameter of the inorganic compound particles is too large, the stability and electrical characteristics of the coating solution may be deteriorated. The particle diameter may be uniform or a composite system having different particle diameters. For example, a volume average primary particle diameter of 0.1 μm and 0.03 μm may be mixed and used.

  When inorganic compound particles are included, the content ratio of the inorganic compound particles and the alcohol-soluble resin can be arbitrarily selected. However, from the viewpoint of the stability of the coating liquid, electrical characteristics, and image characteristics, the total alcohol-soluble resin is 1 mass. The range of 0.5 to 6 parts by mass with respect to parts is preferred. Especially preferably, it is the range of 0.8 mass part to 4 mass parts. When there are too many inorganic compound particles, the image characteristics and the stability of the coating solution may be deteriorated, and when there are too few, the electric characteristics may be deteriorated.

[[Other ingredients in the undercoat layer]]
In the undercoat layer of the electrophotographic photoreceptor of the present invention, an additive such as an antioxidant and a leveling agent, a conductive agent, other resins, etc. (hereinafter abbreviated as “other components”) as necessary. May be added.

[[Coating solvent for undercoat layer]]
The undercoat layer containing an alcohol-soluble resin used in the electrophotographic photoreceptor of the present invention is essential to be formed from a coating solution containing at least a tertiary alcohol as a coating solvent.

  Any tertiary alcohol can be used as long as it is liquid at 25 ° C. and 1 atm, and the above-described effects of the present invention can be exhibited. In addition, a substituent may be bonded. Non-functional groups such as alkyl groups, cycloalkyl groups, phenyl groups, alkenyl groups, ester groups, amide groups, dialkylamino groups, keto groups, ether groups, cyano groups, nitro groups, halogen groups; amino groups And a functional group such as a monoalkylamino group, a carboxyl group, a primary hydroxyl group, and a secondary hydroxyl group, but a non-functional group or a primary or secondary hydroxyl group is preferred. However, those having no substituent other than an alkyl group are particularly preferred from the viewpoint of the drying property of the coating film. These tertiary alcohols may be used alone or in combination of two or more.

  The tertiary alcohol preferably has 4 to 8 total carbon atoms, including substituents, and particularly preferably has 4 to 6 carbon atoms. Moreover, the thing of 30 to 150 degreeC boiling point in 1 atmosphere is preferable, and the thing of 50 to 100 degreeC is especially preferable.

  Specific preferred tertiary alcohols include tert-butanol (2-methyl-2-propanol), 2-methyl-2-butanol, 2-methyl-2-pentanol, and the like. Among them, tert-butanol or 2-methyl-2-butanol is particularly preferable in terms of the drying property of the coating film.

  If it is a liquid at 25 ° C. and 1 atm together with the tertiary alcohol, the primary alcohol having 1 to 10 carbon atoms and optionally having a substituent other than the tertiary alcohol may be substituted. It is preferable to use a mixture of a secondary alcohol (hereinafter abbreviated as “other alcohol”). Such primary or secondary alcohol is not particularly limited, but methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol and the like are preferable, and methanol is the solubility and coating of alcohol-soluble resin. It is particularly preferable in terms of the drying property of the film. These other alcohols may be used alone or in combination of two or more.

  A solvent other than alcohol (hereinafter abbreviated as “other solvent”) can be used in combination as long as the solubility of the resin is not deteriorated and the dispersibility of the particles is not deteriorated. Include aliphatic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, and the like. Among these, aromatic carbon hydrogen is preferable from the viewpoint of the solubility of the alcohol-soluble resin and the drying property of the coating film, and among these, toluene or xylene is particularly preferable. These other solvents may be used alone or in combination of two or more.

  The coating solution for the undercoat layer in the present invention is characterized by containing at least a tertiary alcohol, and the tertiary alcohol is preferably in the range of 10% by mass to 60% by mass with respect to the total amount of solvent. A range of 20% by mass to 50% by mass is particularly preferable. If the amount of tertiary alcohol is too small, uniformity of the film thickness of the undercoat layer may not be obtained. On the other hand, if it is too large, the solubility of the alcohol-soluble resin may be deteriorated.

  The content ratio of the tertiary alcohol and the other alcohol is that the other alcohol is in the range of 50% by mass to 300% by mass with respect to the whole tertiary alcohol. It is preferable in terms of the solubility of the soluble resin, and particularly preferably in the range of 100% by mass to 200% by mass. In terms of the solubility of the alcohol-soluble resin, the content ratio of “other solvent” should not exceed the amount of “total of tertiary alcohol and other alcohol”. preferable.

[[Undercoat layer thickness and formation method]]
As the film thickness of the undercoat layer, it can be used in a film thickness within a range usually used as an electrophotographic photosensitive member, but is usually 0.1 μm to 30 μm, preferably 0.5 μm to 15 μm, more preferably 1 μm to 10 μm, Preferably it is 1 micrometer-6 micrometers. Furthermore, in the present invention, it is effective when the thickness of the undercoat layer is 3 μm or more, and particularly effective when it is 5 μm or more. If the film thickness is too thin, the effect of improving image defects may be insufficient. On the other hand, if it is too thick, the electrical characteristics as an electrophotographic photosensitive member may be insufficient.

  As long as the undercoat layer can be applied to a certain degree of uniformity, any coating method may be used, but it may be applied according to a conventional method using a dip coating method, a spray coating method, a nozzle coating method, or the like. Among them, the dip coating method is preferable because it is excellent in production efficiency.

  As an example of the dip coating method, an alcohol-soluble resin, inorganic compound particles if necessary, and other components if necessary are further added to the solvent / dispersion medium, and the total solid concentration is preferably relative to the entire coating liquid. Is 1 to 50% by mass, particularly preferably 10 to 35% by mass. The viscosity of the coating solution is preferably 3 centipoise or more, particularly preferably 10 centipoise or more, and the upper limit is preferably 100 centipoise or less, particularly preferably 60 centipoise or less to prepare a coating solution for forming the undercoat layer. To do.

  Then, although a coating film is dried, drying temperature and drying time are adjusted so that necessary and sufficient drying may be performed. A drying temperature is 100-250 degreeC normally, Preferably it is 110-170 degreeC, More preferably, it is the range of 115-140 degreeC. Examples of the drying method include a method using a hot air dryer, a steam dryer, an infrared dryer, a far infrared dryer and the like. However, it is preferable from the viewpoint of production efficiency that the undercoat layer is dried at room temperature, and a photosensitive layer is formed thereon and then heat-dried.

[Coating film in general]
The effect of the undercoat layer is the same for the coating film in general with respect to the coating property. Therefore, it is a coating film containing at least an alcohol-soluble resin and inorganic compound particles, and the coating film is formed from a coating solution containing at least a tertiary alcohol as a coating solvent. The coating film has a uniform film thickness and is smooth. In addition, when the alcohol-soluble resin is a polyamide resin, the effect is remarkable, and it can be said that the coating film in general is the same. The coating film is not particularly limited, and examples thereof include a photosensitive layer of an electrophotographic photoreceptor, a coating film for a blocking layer for electronic paper, and a coating film for coating a metal material such as various pipes and tanks.

[Photosensitive layer]
The electrophotographic photosensitive member has an undercoat layer and a photosensitive layer on a conductive substrate. The photosensitive layer includes a single layer type and a laminated type in which the charge generation layer and the charge transport layer are functionally separated, and the laminated type is preferable.

[[Charge generation layer in stacked type]]
In the case of a laminated type in which the photosensitive layer is functionally separated, a charge generation layer is provided on the undercoat layer, and the charge generation layer contains a charge generation material. There are no particular limitations on the charge generating material, but phthalocyanine pigments, azo pigments, dithioketopyrrolopyrrole pigments, squalene (squarylium) pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments, benzimidazole pigments Etc.

  As the phthalocyanine pigment, there are metal-free phthalocyanine, titanyl phthalocyanine, gallium phthalocyanine, indium phthalocyanine, vanadium phthalocyanine, copper phthalocyanine, etc., preferably gallium phthalocyanine pigment, metal-free phthalocyanine pigment, titanyl phthalocyanine pigment, and among them, titanyl phthalocyanine A pigment is particularly preferable, and oxytitanium phthalocyanine having a specific crystal system is more preferable.

  A phthalocyanine pigment may use only a single compound, and may be used in a some mixed state. Here, as a method for forming a mixed state in a mixed state or a crystalline state of the phthalocyanine pigment, the respective constituent elements may be mixed and used later, or production of a phthalocyanine pigment for synthesis, pigmentation, crystallization, etc. -The thing which produced the mixed state in the process process may be used. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are used. In particular, an electrophotographic photoreceptor using a so-called mixed crystal state phthalocyanine pigment which is a mixed state in a crystalline state shows a particularly high sensitivity and is preferable because a sensitivity change with respect to environmental changes such as a temperature change is small.

  The charge generation material is used alone or in combination with a binder resin to form the charge generation layer. Binder resins for the charge generation layer include polymers or copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylic acid ester, methacrylic acid ester, vinyl alcohol, ethyl vinyl ether, polyvinyl acetal, polycarbonate, polyester, polyamide , Polyurethane, cellulose ether, phenoxy resin, silicon resin, epoxy resin, and the like. Polyvinyl acetal is preferable in terms of pigment dispersibility.

  The ratio between the charge generation material and the binder resin is not particularly limited, but generally, 5 to 500 parts by mass, preferably 20 to 300 parts by mass of the binder polymer is used with respect to 100 parts by mass of the charge generation material. The charge generation layer may be a vapor deposition film of the charge generation material.

  In addition, the charge generation layer may contain various additives such as a leveling agent, an antioxidant, and a sensitizer for improving coating properties as necessary.

  When forming the charge generation layer, the charge generation material is dispersed or dissolved in an appropriate dispersion medium using a ball mill, ultrasonic disperser, paint shaker, attritor, sand grinder, etc., and a binder resin is added as necessary to charge the charge generation layer. The coating solution for forming the generation layer is prepared, and this coating solution is formed by coating. When the charge generating material is used alone, the coating solution may be prepared and applied without adding a binder to the dispersion, or may be formed by a method such as vapor deposition or sputtering. The film thickness of the charge generation layer is usually 0.05 to 5 μm, preferably 0.1 to 2 μm.

[[Charge transport layer in stacked type]]
A charge transport layer is provided on the charge generation layer. The charge transport layer contains at least a binder resin and a charge transport material, but may contain an electron-withdrawing compound, a plasticizer, a pigment, and other additives as necessary.

  When the electrophotographic photoreceptor of the present invention has a function-separated type photosensitive layer, examples of the charge transport material in the charge transport layer include polymer compounds such as polyvinyl carbazole, polyvinyl pyrene, and polyacenaphthylene; diphenoquinone derivatives, 2, Aromatic nitro compounds such as 4,7-trinitrofluorenone, carbazole derivatives, indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, oxadiazole derivatives, pyrazoline derivatives, heterocyclic compounds such as thiadiazole derivatives, aniline derivatives, hydrazone derivatives , Arylamine derivatives, stilbene derivatives, butadiene derivatives, enamine compounds, those in which a plurality of these compounds are bonded, or polymers having groups composed of these compounds in the main chain or side chain. In addition, you may use the said charge transport material in mixture of 2 or more types.

  As the binder resin for the charge transport layer, a resin having good compatibility with the above charge transport material and that does not crystallize or phase separate after formation of the coating film is preferable. Examples thereof include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylic acid ester, methacrylic acid ester, vinyl alcohol, ethyl vinyl ether, polyvinyl acetal, polycarbonate, polyarylate, polyester, polysulfone. , Polyphenylene oxide, polyurethane, cellulose ester, cellulose ether, phenoxy resin, silicon resin, epoxy resin and the like.

  Electron-withdrawing compounds include tetracyanoquinodimethane, dicyanoquinomethane, cyano compounds such as aromatic esters having a dicyanoquinovinyl group, nitro compounds such as 2,4,6-trinitrofluorenone, and condensation of perylene. Polycyclic aromatic compounds, diphenoquinone derivatives, quinones, aldehydes, ketones, esters, acid anhydrides, phthalides, metal complexes of substituted and unsubstituted salicylic acid, metal salts of substituted and unsubstituted salicylic acid, aromatic carboxylic acids And metal salts of aromatic carboxylic acids. Preferably, a cyano compound, a nitro compound, a condensed polycyclic aromatic compound, a diphenoquinone derivative, a metal complex of substituted and unsubstituted salicylic acid, a metal salt of substituted and unsubstituted salicylic acid, a metal complex of aromatic carboxylic acid, an aromatic carboxylic acid Metal salts are used.

  The content ratio of the charge transport material and the binder resin is preferably 10 parts by mass or more, and particularly preferably 30 parts by mass or more with respect to 100 parts by mass of the binder resin. Moreover, 200 mass parts or less are preferable, and 150 mass parts or less are especially preferable. If the content ratio of the binder resin is too large, the electrical characteristics may be deteriorated. In addition, the charge transport material is usually compatible with the binder resin and has a high influence on the mechanical properties of the photosensitive layer. Therefore, if the content ratio of the charge transport material is too large, the mechanical strength of the photosensitive layer is lowered. There is a case.

  In order to improve the film forming property, flexibility, coating property, stain resistance, gas resistance, light resistance, etc. in the charge transport layer, or to further improve the mechanical strength of the photosensitive layer, a well-known plasticizer, It is also preferable to add additives such as a lubricant, a dispersion aid, an antioxidant, an ultraviolet absorber, an electron-withdrawing compound, a dye, a pigment, a sensitizer, a leveling agent, a stabilizer, a fluidity-imparting agent, and a crosslinking agent. . Examples of the antioxidant include hindered phenol compounds and hindered amine compounds. Examples of dyes and pigments include various pigment compounds and azo compounds. Examples of surfactants include silicone oil and fluorine oil.

  Although the formation method of a charge transport layer is mentioned later, the film thickness of a charge transport layer is 10 micrometers-50 micrometers normally, Preferably it is 13 micrometers-35 micrometers.

[[Photosensitive layer in single layer type]]
When the photosensitive layer is a single layer type, a single photosensitive layer is provided on the undercoat layer. The single photosensitive layer preferably contains at least the phthalocyanine pigment described above and a binder resin, and includes the other charge generation material, the charge transport material, and the electron withdrawing material. Also good.

  At this time, the particle size of the charge generating material needs to be sufficiently small, and is preferably 1 μm or less, more preferably 0.5 μm or less. The amount of the charge generating material dispersed or dissolved in the single-layer type photosensitive layer is, for example, in the range of 0.5 to 50% by mass with respect to the entire photosensitive layer. If the amount is too small, sufficient sensitivity cannot be obtained. If the amount is too large, there are problems such as a decrease in chargeability and a decrease in sensitivity. Particularly preferably, it is used in the range of 1 to 20% by mass. The content ratio of the charge transport material and the binder resin is preferably 30 parts by mass or more, and particularly preferably 40 parts by mass or more with respect to 100 parts by mass of the binder resin. Moreover, 80 mass parts or less are preferable, and 60 mass parts or less are especially preferable.

  As in the case of the charge transport layer in the multilayer photosensitive layer, if the content ratio of the binder resin is too large, the electrical characteristics may be deteriorated. In addition, since the charge transport material is usually compatible with the binder resin, if the content ratio of the charge transport material is too large, the mechanical strength of the photosensitive layer may be lowered. Furthermore, the same additive as that which can be blended in the charge transport layer in the multilayer photosensitive layer can be used in the single-layer photosensitive layer.

  The coating solution obtained by blending the predetermined components is applied on the undercoat layer and dried to form a single-layer type photosensitive layer. The film thickness is usually 2 μm to 70 μm, preferably 10 μm to 45 μm, Especially preferably, it is 20 micrometers-35 micrometers.

[[General production method of photosensitive layer]]
Solvents and dispersion media used when applying the above layers include butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, benzene, toluene, Xylene, chloroform, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethane, dichloromethane, tetrahydrofuran, dioxane, methyl alcohol , Ethyl alcohol, isopropyl alcohol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosolve and the like. These solvents may be used alone or in combination of two or more.

  As a method for coating and forming a photosensitive layer, a spray coating method, a bar coater method, a blade method, a roll coater method, a wire bar coating method, a knife coater coating method, which are usually used for coating and forming a photosensitive layer of an electrophotographic photosensitive member. Any coating method such as a spiral coating method, a ring coating method, a dip coating method, or a spinner coating method can be used. A photosensitive layer is obtained by applying and then drying the coating solution.

  Spray coating methods include air spray, airless spray, electrostatic air spray, electrostatic airless spray, rotary atomizing electrostatic spray, hot spray, and hot airless spray. Considering the degree of conversion, adhesion efficiency, etc., in the rotary atomizing electrostatic spray, the conveying method disclosed in the republished Japanese Patent Publication No. 1-805198, that is, the cylindrical workpiece is rotated while the axial direction is spaced. By using a continuous conveyance method, it is possible to obtain an electrophotographic photoreceptor excellent in film thickness uniformity with high overall deposition efficiency.

  Examples of the spiral coating method include a method using a liquid injection coating machine or a curtain coating machine disclosed in Japanese Patent Laid-Open No. 52-119651, and paint from a minute opening disclosed in Japanese Patent Laid-Open No. 1-2231966. A method of flying continuously in a streak shape, a method using a multi-nozzle body disclosed in JP-A-3-193161, and the like are used.

  As an example of the dip coating method, the following charge transport layer coating formation procedure may be mentioned. Using a charge transport material, binder resin, solvent, etc., the total solid concentration is preferably 15% by mass or more, particularly preferably 40% by mass or less, and the viscosity is preferably 50 centipoises or more, particularly preferably 100 centipoises or more. A coating solution for forming a charge transport layer, preferably 700 centipoise or less, particularly preferably 500 centipoise or less is prepared. Here, the viscosity of the coating solution is substantially determined by the molecular weight of the binder resin, but as described above, when the molecular weight is too low, the mechanical strength of the photosensitive layer is lowered, so that the binder has a molecular weight that does not impair this. It is preferable to use a resin. A photosensitive layer such as a charge transport layer is formed by a dip coating method using the coating solution thus prepared.

  Thereafter, the coating film is dried, and the drying temperature and drying time are adjusted so that necessary and sufficient drying is performed. A drying temperature is 100-250 degreeC normally, Preferably it is 110-170 degreeC, More preferably, it is the range of 115-140 degreeC. Examples of the drying method include a method using a hot air dryer, a steam dryer, an infrared dryer, a far infrared dryer and the like.

  Further, the photosensitive layer of the electrophotographic photoreceptor of the present invention may be a single-layer type or a functionally separated laminated type, and is a known plasticizer for improving the film formability, flexibility, coatability, and mechanical strength. , An antioxidant, an ultraviolet absorber, and a leveling agent may be contained. Furthermore, 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, it goes without saying that an adhesive layer, an intermediate layer, a transparent insulating layer, and the like may be provided as necessary.

[Image forming apparatus]
Next, an image forming apparatus using the electrophotographic photosensitive member 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 photosensitive member 1 is not particularly limited as long as it is the above-described electrophotographic photosensitive member of the present invention. In FIG. 1, as an example, a drum shape in which the photosensitive layer described above is formed on the surface of a cylindrical conductive substrate. 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 photoreceptor 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. In FIG. 1, a roller-type charging device (charging roller) is shown as an example of the charging device 2, but as a charging method, a contact charging method using a charging roller, a charging brush, a charging sheet, etc .; corotron, scorotron, etc. Examples include the corona charging method used.

  Among them, the contact charging method is preferable because the electrophotographic apparatus can be made compact and the amount of ozone generated during charging can be reduced. In addition, since the characteristic of the undercoat layer in the electrophotographic photosensitive member of the present invention is to suppress leakage (dielectric breakdown), it can be applied to a contact charging method that is relatively easy to generate leakage (dielectric breakdown). This is preferable in order to make full use of the effect of the present invention in which the pulling layer has leak resistance. Particularly preferred is a contact charging method using a charging roller.

  In many cases, the electrophotographic photosensitive member 1 and the charging device 2 are designed to be removable from the main body of the image forming apparatus as a cartridge including both of them (hereinafter, also referred to as “photosensitive cartridge”). Yes. For example, when the electrophotographic photoreceptor 1 or the charging device 2 is deteriorated, the photoreceptor cartridge can be detached from the image forming apparatus main body, and another new photoreceptor cartridge can be mounted on the image forming apparatus main body. It has become. Also, in many cases, toner is stored in a toner cartridge and designed to be removable from the main body of the image forming apparatus. When the toner in the used toner cartridge runs out, this toner cartridge is formed into an image. It can be removed from the main body and another new toner cartridge can be mounted. Further, a cartridge equipped with all of the electrophotographic photosensitive member 1, the charging device 2, and the toner may be used.

  There are no particular restrictions on the type of exposure apparatus 3 as long as it can perform image exposure on the electrophotographic photoreceptor 1 and form an electrostatic latent image on the photosensitive surface of the electrophotographic photoreceptor 1. Examples of the light source of the apparatus 3 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, if the exposure is performed with monochromatic light having a wavelength of 780 nm, monochromatic light having a wavelength of 600 nm to 700 nm, slightly short wavelength, monochromatic light having a wavelength of 380 nm to 500 nm, or the like. Good.

  The type of the developing device 4 is not particularly limited, and any device such as a dry development method such as cascade development, one-component conductive toner development, two-component magnetic brush development, or a wet development method can be used. 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 is configured to store toner T 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. This 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 a 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, the transfer device 5 is composed of a transfer charger, a transfer roller, a transfer belt, and the like 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.

  The cleaning device 6 is for scraping off residual toner adhering to the photoreceptor 1 with a cleaning member and collecting the residual toner. 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. In the present invention, since polymerized toner is used, the condition for scraping off by the cleaning member becomes strong, and the load on the photoreceptor 1 may increase.

  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. The upper and lower fixing members 71 and 72 are 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 in which polytetrafluoroethylene resin is coated, and a fixing sheet. Can be used. 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 an arbitrary method such as heat roller fixing, flash fixing, oven fixing, pressure fixing, or the like can be provided.

[Record image]
In the image forming apparatus using the electrophotographic photosensitive member 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.

[Action / Principle]
When a coating solution containing a tertiary alcohol is used as the undercoat layer of the electrophotographic photosensitive member of the present invention, a uniform coating film is obtained, and the action and principle that image defects are less likely to occur are not clear. Although the present invention is not limited to the action and principle, it can be considered as follows. That is, generally, the surface tension of the alcohol solvent is large, so that the coating film is not uniform and smooth, and the problem becomes more serious as the film thickness increases. In addition, when inorganic compound particles are contained, the physical properties such as specific gravity and specific heat differ greatly between the binder resin and the inorganic compound particles, and the convection in the coating film during drying tends to be large, and the coating film is uniform and smooth. It is hard to become. If tertiary alcohol is contained therein, it is presumed that surface tension and convection are suitably controlled.

  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.

(Method for preparing dispersion P1)
Rutile type titanium oxide having a volume average primary particle diameter of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% by mass of 1-trifluoro-2-difluoro-3-difluoro-4-difluoro-based on the titanium oxide 5-Difluoro-6-difluorooctyltrimethoxysilane (“TSL8257” manufactured by GE Toshiba Silicone) was charged into a high-speed fluidized mixing kneader (“SMG300” manufactured by Kawata), and the rotational peripheral speed was 34.5 m / sec. The surface-treated titanium oxide obtained by high-speed mixing in 1 was dispersed by a ball mill in a methanol solvent to obtain a surface-treated titanium oxide dispersion that was a dispersion of inorganic compound particles. Dispersion conditions were surface-treated titanium oxide / methanol = 1/3 (mass ratio), and a ball mill ball was an alumina ball having a diameter of 5 mm.

  As the alcohol-soluble resin, ε-caprolactam [compound represented by the following formula (A)] / bis (4-amino-3-methylcyclohexyl) methane [compound represented by the following formula (B)] / hexamethylenediamine [following The composition molar ratio of the compound represented by the formula (C)] / decamethylene dicarboxylic acid [the compound represented by the following formula (D)] / octadecamethylene dicarboxylic acid [the compound represented by the following formula (E)] was 40%. A random copolymerized polyamide resin having a number average molecular weight of 13000 comprising / 25% / 5% / 25% / 5% was used.

To the above-described surface-treated titanium oxide dispersion, methanol, tert-butanol and toluene are added with stirring so that the final composition becomes the following composition, and the above-mentioned copolyamide resin pellets are further added to the following final composition. The mixture was mixed while stirring, and then stirred and mixed while heating at 60 ° C. Further, ultrasonic dispersion was performed, and finally the dispersion was adjusted to have the following composition to obtain dispersion P1.
-Solid content concentration: 29% by mass
Solid composition ratio: Titanium oxide / copolymerized polyamide resin = 4/1 (weight ratio)
Solvent composition ratio: methanol / tert-butanol / toluene = 4/4/2 (weight ratio)

(Production method of dispersion P2)
Dispersion P1 was diluted with a mixed solvent having the above ratio to obtain a dispersion P2 with a solid content concentration of 27% by mass.

(Production method of dispersion liquid Q1)
Dispersion liquid Q1 was obtained by the same method as the preparation method of dispersion liquid P1, except that the solid content concentration and the solvent composition ratio were changed as shown below.

-Solid content concentration: 28% by mass
Solvent composition ratio: methanol / tert-butanol / toluene = 4/3/3 (weight ratio)

(Production method of dispersion R1)
A dispersion R1 having a solid content concentration of 29% by mass was obtained by the same method as that for the dispersion P1, except that the type of solvent and the solvent composition ratio were changed as shown below.
Solvent composition ratio: methanol / 2-methyl-2-butanol / toluene = 4/3/3 (weight ratio)

(Production Method of Dispersion S1)
A dispersion S1 having a solid content concentration of 29% by mass was obtained in the same manner as the preparation of the dispersion P1, except that the type of solvent and the solvent composition ratio were changed as shown below.
Solvent composition ratio: methanol / 1-propanol / toluene = 5/2/3 (weight ratio)

(Production method of dispersion liquid S2)
Dispersion S1 was diluted with a mixed solvent having the above ratio to obtain a dispersion S2 with a solid concentration of 28% by mass.

(Production method of dispersion S3)
Dispersion S1 was diluted with a mixed solvent having the above ratio to obtain a dispersion S3 with a solid concentration of 27% by mass.

(Production method of dispersion liquid T1)
A dispersion T1 having a solid content concentration of 29% by mass was obtained by the same method as that for the dispersion P1, except that the type of solvent and the solvent composition ratio were changed as shown below.
Solvent composition ratio: methanol / 1-propanol / toluene = 4/3/3 (weight ratio)

(Production method of dispersion T2)
Dispersion T1 was diluted with a mixed solvent having the above ratio to obtain a dispersion T2 with a solid concentration of 28% by mass.

(Preparation method of dispersion T3)
Dispersion T1 was diluted with a mixed solvent in the above ratio to obtain a dispersion T3 with a solid content concentration of 27% by mass.

(Method for producing dispersion U1)
A dispersion U1 having a solid content concentration of 29% by mass was obtained by the same method as that for the dispersion P1, except that the type of solvent and the solvent composition ratio were changed as shown below.
Solvent composition ratio: methanol / 1-propanol / toluene = 6/1/3 (weight ratio)

(Method for preparing dispersion U2)
Dispersion U1 was diluted with a mixed solvent having the above ratio to obtain a dispersion U2 with a solid content concentration of 27% by mass.

Example 1
An aluminum cylinder having an outer diameter of 30 mm, a length of 254 mm and a wall thickness of 1.0 mm is dip-coated on dispersion P1, and an undercoat layer is provided so that the dry film thickness is 5.5 μm. It was. This drum is referred to as drum A1.

Example 2
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion P2 was used instead of the dispersion P1 and the dry film thickness was changed to 3.0 μm. This drum is referred to as drum B1.

Example 3
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion P2 was used in place of the dispersion P1 and the dry film thickness was 4.0 μm. This drum is referred to as drum B2.

Example 4
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion P2 was used in place of the dispersion P1 and the dry film thickness was 4.9 μm. This drum is referred to as drum B3.

Example 5
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion P2 was used instead of the dispersion P1 and the dry film thickness was 7.0 μm. This drum is referred to as drum B4.

Example 6
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion liquid Q1 was used instead of the dispersion liquid P1 and the dry film thickness was changed to 5.5 μm. This drum is referred to as drum C1.

Example 7
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion liquid R1 was used instead of the dispersion liquid P1 and the dry film thickness was changed to 4.0 μm. This drum is referred to as drum D1.

Example 8
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion R1 was used in place of the dispersion P1 and the dry film thickness was 5.0 μm. This drum is referred to as drum D2.

Comparative Example 1
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion S1 was used in place of the dispersion P1 and the dry film thickness was 5.0 μm. This drum is referred to as drum E1.

Comparative Example 2
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion liquid S2 was used instead of the dispersion liquid P1 and the dry film thickness was changed to 4.0 μm. This drum is referred to as drum F1.

Comparative Example 3
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion S2 was used in place of the dispersion P1 and the dry film thickness was 5.0 μm. This drum is referred to as drum F2.

Comparative Example 4
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion S3 was used in place of the dispersion P1 and the dry film thickness was 3.2 μm. This drum is referred to as drum G1.

Comparative Example 5
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion S3 was used instead of the dispersion P1 and the dry film thickness was 4.0 μm. This drum is referred to as drum G2.

Comparative Example 6
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion liquid T1 was used in place of the dispersion liquid P1 and the dry film thickness was 5.0 μm. This drum is referred to as drum H1.

Comparative Example 7
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion liquid T2 was used instead of the dispersion liquid P1 and the dry film thickness was changed to 4.0 μm. This drum is referred to as drum I1.

Comparative Example 8
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion T2 was used instead of the dispersion P1 and the dry film thickness was 5.5 μm. This drum is referred to as drum I2.

Comparative Example 9
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion liquid T3 was used instead of the dispersion liquid P1 and the dry film thickness was changed to 3.5 μm. This drum is referred to as drum J1.

Comparative Example 10
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion liquid T3 was used instead of the dispersion liquid P1 and the dry film thickness was changed to 4.0 μm. This drum is referred to as drum J2.

Comparative Example 11
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion T3 was used instead of the dispersion P1 and the dry film thickness was 4.8 μm. This drum is referred to as drum J3.

Comparative Example 12
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion U1 was used in place of the dispersion P1 and the dry film thickness was 4.4 μm. This drum is referred to as drum K1.

Comparative Example 13
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion liquid U2 was used instead of the dispersion liquid P1 and the dry film thickness was changed to 3.0 μm. This drum is referred to as drum L1.

Comparative Example 14
An undercoat layer was provided in the same manner as in Example 1 except that the dispersion U2 was used in place of the dispersion P1 and the dry film thickness was 3.8 μm. This drum is referred to as a drum L2.

  Next, with respect to the drums A1 to L2 provided with the undercoat layer, the average surface roughness was measured according to JIS B0601 using a surface roughness measuring device (trade name: Surfcom 570) manufactured by Tokyo Seimitsu at a position 120 mm from the upper end of the coating. The thickness (Ra) was measured. The measurement results are shown in Table 1.

  As is apparent from Table 1, in the examples, the average surface roughness (Ra) of the undercoat layer coated with a coating solution containing tert-butanol or 2-methyl-2-butanol as a coating solvent is the film thickness. Although the film thickness was changed from 3.0 μm to 7.0 μm, all were 0.07 μm or less, and a coating film having a smooth and uniform surface was formed.

  On the other hand, the average surface roughness (Ra) of the undercoat layer coated with the coating solution containing no tertiary alcohol, which is a comparative example, is 0.10 μm or more, and the surface becomes rough compared to the examples. I found out. In particular, when the film thickness was 5.0 μm or more, Ra was all 0.20 μm or more and was further deteriorated.

  As described above, it can be judged that the undercoat layer of the above-described embodiment of the electrophotographic photosensitive member of the present invention has a very excellent effect for forming a coating film having a smooth and uniform surface. Due to this uniformity, leakage (dielectric breakdown) can be suppressed, and an electrophotographic photosensitive member with good image quality in which the problems of image defects and image density unevenness can be solved can be obtained.

  As the undercoat layer, the fact that the film thickness is uniform and smooth can be said to be the same in general coating films. Therefore, the above evaluation result can be applied to general coating films.

  The electrophotographic photosensitive member of the present invention is used in all fields that require it, and is widely used in, for example, copying machines, printers, printing machines, and the like. Furthermore, since the coating film of the present invention is uniform and smooth, such as a coating film containing inorganic catalyst particles, a coating film for forming a blocking layer for electronic paper, a coating film for coating a metal material such as various pipes and tanks, It is widely used in the field of using a coating film that may contain an alcohol-soluble resin and inorganic compound particles.

1 is a conceptual diagram illustrating an example 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 (5)

An electrophotographic photoreceptor having at least an undercoat layer containing an alcohol-soluble resin and a photosensitive layer on a conductive substrate, wherein the undercoat layer has 1 to 10 carbon atoms and has a substituent. An electrophotographic photoreceptor characterized in that it is formed from a coating solution containing an optional primary and / or secondary alcohol, tertiary alcohol, and aromatic hydrocarbon as a coating solvent. .   The electrophotographic photosensitive member according to claim 1, wherein the alcohol-soluble resin is a polyamide resin.   The electrophotographic photosensitive member according to claim 1, wherein the undercoat layer contains inorganic compound particles.   The electrophotographic photosensitive member according to claim 1, wherein the undercoat layer has a thickness of 3 μm or more. An image forming apparatus using the electrophotographic photosensitive member according to any one of claims 1 to 4 as a charging method for the electrophotographic photosensitive member, and a contact charging method.

Images