JP6794797B2 - Electrophotographic photosensitive member, image forming apparatus and process cartridge - Google Patents

Description

The present invention relates to electrophotographic photosensitive members, image forming devices and process cartridges.

In an image forming method using an image forming apparatus, an image is formed by subjecting an electrophotographic photosensitive member to steps such as a charging step, an exposure step, a developing step, and a transfer step. In recent years, as a material constituting an electrophotographic photosensitive member, an organic material has been widely used in view of its advantages in flexibility, thermal stability, film forming property and the like.

An image forming apparatus having an electrophotographic photosensitive member using an organic material is rapidly becoming full-color and high-speed, and is not limited to general office business fields, for example, is light and does not require advanced printing technology. It is also used in the printing business field. In particular, in the light printing business field, the number of printed sheets has increased remarkably. Therefore, the electrophotographic photosensitive member is particularly required to have an image quality that does not cause background stains during image formation for a long period of time.

The organic material constituting the electrophotographic photosensitive member is gradually deteriorated by the electrostatic load in the current electrophotographic process in which charging and static electricity removal are repeated, resulting in a decrease in chargeability. When the chargeability is lowered, the image quality of the output image is greatly affected, which may cause a decrease in image density, background stains, and a decrease in image homogeneity during continuous output. It is considered that one of the causes of such deterioration of image quality is the undercoat layer constituting the electrophotographic photosensitive member. Therefore, in order to improve the image quality of the electrophotographic photosensitive member, improvement of the undercoat layer of the electrophotographic photosensitive member is being studied.

For example, an organic photoconductor having an undercoat layer containing a binder resin, metal oxide particles, and a compound having a thiol group is disclosed (see, for example, Patent Document 1).

However, even if the above-mentioned conventional technique is used, if an image is formed for a long period of time in a harsh environment such as high temperature and high humidity (for example, 27 ° C. and relative humidity of 80% RH), the image may have black spots or white spots. Image defects with color spots may occur. Therefore, when using an electrophotographic photosensitive member in an electrophotographic image forming apparatus, a process cartridge, or the like, it is desired that the image quality of the electrophotographic photosensitive member can be maintained more stably for a long period of time.

One aspect of the present invention is to provide an electrophotographic photosensitive member capable of reducing the occurrence of color spots and obtaining stable image quality.

The electrophotographic photosensitive member according to the embodiment of the present invention has a support, a photosensitive layer, and an undercoat layer containing zinc oxide and a binder resin, and the support has Si: 0.10 to 0. It contains an aluminum alloy consisting of 25% by mass, Fe: 0.10 to 0.40% by mass, Mn: 0.02 to 0.05% by mass, unavoidable impurities, and the balance Al, and the undercoat layer contains a salicylic acid derivative. Including, the specular reflectance of the undercoat layer is 85% or more.

The electrophotographic photosensitive member according to the embodiment of the present invention can reduce the occurrence of color spots and obtain stable image quality.

FIG. 1 is a cross-sectional view showing an example of the layer structure of the electrophotographic photosensitive member according to the embodiment. FIG. 2 is a cross-sectional view showing an example of another layer structure of the electrophotographic photosensitive member according to the embodiment. FIG. 3 is a cross-sectional view showing an example of another layer structure of the electrophotographic photosensitive member according to the embodiment. FIG. 4 is a cross-sectional view showing an example of another layer structure of the electrophotographic photosensitive member according to the embodiment. FIG. 5 is a schematic configuration diagram showing an example of an image forming apparatus according to an embodiment. FIG. 6 is a schematic configuration diagram showing an example of a process cartridge according to an embodiment.

Hereinafter, embodiments according to the present invention will be described. For ease of understanding, the scale of each member in the drawing may differ from the actual scale. Further, the embodiment is not limited by the following description, and can be appropriately changed without departing from the gist of the present invention. Further, for convenience of explanation of the layer structure and the like, in the example shown below, the explanation is given together with the figure in which the support is arranged below, but the embodiment is not necessarily manufactured or used in this arrangement. .. Further, in the following description, one side in the thickness direction of the support may be referred to as upper or upper, and the other in the thickness direction of the support may be referred to as lower or lower.

<Electrophotophotoreceptor>
The electrophotographic photosensitive member according to the embodiment has a support, an undercoat layer, and a photosensitive layer, and the undercoat layer and the photosensitive layer are laminated in this order on the support. The electrophotographic photosensitive member according to the embodiment further has other layers, if necessary.

[Support]
The support has a conductivity having a volume resistivity of 1 × 10 ¹⁰ Ω · cm or less. The support is formed by using an aluminum alloy containing Si, Fe, Mn, unavoidable impurities, and Al as a balance.

The Si content is preferably 0.10 to 0.25% by mass, and preferably 0.15 to 0.20% by mass. If the Si content exceeds 0.25% by mass, shrinkage cavities and cracks may occur on the surface of the support. In particular, when the support is formed by cutting a lump made of an aluminum alloy, shrinkage cavities and cracks are likely to occur on the cut surface and the like. On the other hand, when the Si content is less than 0.10% by mass, the strength of the support becomes low, which may make it unsuitable as an electrophotographic photosensitive member.

The Fe content is preferably 0.10 to 0.40% by mass, and preferably 0.12 to 0.35% by mass. The Mn content is preferably 0.02 to 0.05% by mass, preferably 0.03 to 0.04% by mass. When the Fe content exceeds 0.40% by mass, or when the Mn content exceeds 0.02% by mass, the Si content is close to the surface of the support as well as when it exceeds 0.25% by mass. Nests and cracks may occur. On the other hand, when the Fe content is less than 0.10% by mass, or when the Mn content is less than 0.05% by mass, and when the Si content is less than 0.10% by mass, the support Since the intensity is low, it may not be suitable as an electrophotographic photosensitive member.

As the unavoidable impurities, for example, O, N, C, Ca, Cu, Mg, Cr, Zn, Ti and the like can be considered. These components may be contained in an amount of, for example, about 0.5% by mass or less.

Since the support is made of an aluminum alloy, components such as Fe and Mn in the aluminum alloy tend to precipitate in the alloy in a matrix. Therefore, when the support is formed by processing a lump of an aluminum alloy, a portion where a component in the aluminum alloy is precipitated may exist as a minute defect on the surface of the support. Therefore, when the electrophotographic photosensitive member is used for a long period of time in an environment of high temperature and high humidity (for example, 27 ° C. and 80% relative humidity RH) with minute defects on the surface of the support, the surface of the support is minute. Due to the defective part, color spots such as black spots and white spots and background stains may occur in the image.

On the other hand, in the present embodiment, the contents of Si, Fe, and Mn as components in the support made of an aluminum alloy are adjusted so as to be within predetermined ranges. As a result, it can be said that the charge transfer on the surface of the support can be stabilized because the minute defect portion generated on the surface of the support can be reduced. As a result, even if the electrophotographic photosensitive member is used for a long period of time in a harsh environment of high temperature and high humidity (for example, 27 ° C. and 80% RH relative humidity), it is caused by minute defects on the surface of the support. It is possible to reduce the occurrence of color spots and background stains on the image.

The support is formed using a molded body made of an aluminum alloy. The method for forming the support is not particularly limited and may be appropriately selected depending on the intended purpose. As a method for forming the support, for example, an aluminum alloy plate is extruded and drawn out to form a cylindrical body, and then the surface of the cylindrical body is cut to perform surface treatment such as superfinishing or polishing. There is a method of applying to form a support. In addition, as a method for forming the support, there is a method for forming the support by coating the plastic such as a film or a cylinder, paper or the like with an aluminum alloy by vapor deposition or sputtering.

[Underlay layer]
The undercoat layer contains at least zinc oxide and a binder resin (binder resin), and further contains other components as needed.

The undercoat layer has a function of suppressing the injection of unnecessary charges (charges having the opposite polarity to the charge polarity of the electrophotographic photosensitive member) from the support to the photosensitive layer, and among the charges formed by the photosensitive layer, the electrophotographic. It is preferable that the photoconductor has a function of transporting a charge having the same polarity as the charge polarity of the photoconductor. For example, when it is necessary to negatively charge the electrophotographic photosensitive member as an image forming process, the undercoat layer has a hole injection blocking function from the support to the photosensitive layer and an electron transport function from the photosensitive layer to the support. It is necessary to combine with. The hole injection blocking function may be referred to as hole blocking property, and the electron transport function may be referred to as electron transport property. In addition, in order to obtain an electrophotographic photosensitive member that can obtain sufficiently stable electrical characteristics and image quality for a long period of time even in a high temperature and high humidity environment, these functions may be subjected to electrostatic load that repeats charging and static electricity removal. It is important that it does not change with temperature and humidity.

The undercoat layer contains zinc oxide in terms of volume resistivity (powder resistivity) and dispersibility. The volume resistivity of the undercoat layer can be appropriately selected depending on the intended purpose, preferably ^{10 2 Ω · cm~10 11 Ω ·} cm. Volume resistivity, if the 10 ² Ω · cm or more, working charge injection inhibition function of the undercoat layer, sufficient leakage resistance can be obtained, less likely to cause an abnormal image quality such as background fouling. On the other hand, if the volume resistivity is less 10 ¹¹ Ω · cm, performed from the photosensitive layer sufficient charge transport to the substrate, without lowering attenuating the residual potential hardly increases.

(Zinc oxide)
The zinc oxide can be appropriately selected depending on the intended purpose, and commercially available zinc oxide can be used. Zinc oxide can be used in the form of particles, powder or the like.

The volume occupancy of the zinc oxide undercoat layer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 40 to 55% or less, and more preferably 45 to 53%. When the volume occupancy is 40% or more, the volume resistivity of the undercoat layer does not become too high, and good electrical characteristics can be maintained. Further, when the volume occupancy is 55% or less, the transmittance of the film is high, the dispersion of zinc oxide in the undercoat layer is good, and sufficient ground stain resistance can be obtained. The volume occupancy of zinc oxide is calculated from the amount and specific gravity of zinc oxide added, the amount and specific gravity of the resin component added, and the amount and specific gravity of other substances added.

The average particle size of zinc oxide is preferably 20 to 200 μm, more preferably 50 to 150 μm. When the average particle size of zinc oxide is 20 μm or more, an undercoat layer in a well-dispersed state can be formed, and when the average particle size of zinc oxide is 150 μm or less, the excellent electrical characteristics of the undercoat layer can be formed. Can be maintained. The average particle size of zinc oxide is the equivalent of a circle of the obtained area obtained by observing 100 zinc oxides observed in the undercoat layer with a transmission electron microscope (TEM) and determining the projected area. The diameter is calculated to obtain the particle size, and the average value is taken as the average particle size.

As described above, the surface of the support is in a state where there are few minute defects. Since zinc oxide has good dispersibility, it can be said that the concentration of zinc oxide in the undercoat layer has little variation and is almost evenly dispersed. In the present embodiment, by laminating the undercoat layer containing zinc oxide on the surface of the support having few minute defects, the transfer of electric charge between the support and the undercoat layer can be made more stable. .. Therefore, even if the electrophotographic photosensitive member is used for a long period of time particularly in an environment of high temperature and high humidity (for example, 27 ° C. and 80% RH relative humidity), the transfer of electric charge between the support and the undercoat layer is still present. Since it is more stable, it is possible to further reduce the occurrence of color spots and background stains on the image.

(Bundling resin)
The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a thermoplastic resin and a thermosetting resin. These may be used alone or in combination of two or more. Among these, as the binder resin, a binder resin having high solvent resistance to general organic solvents is preferable in consideration of coating the photosensitive layer on the undercoat layer. Examples of the binder resin having high solvent resistance include a water-soluble resin, an alcohol-soluble resin, a curable resin forming a three-dimensional network structure, and a butyral resin.

Examples of the water-soluble resin include polyvinyl alcohol, casein, sodium polyacrylate and the like. Examples of the alcohol-soluble resin include copolymerized nylon and methoxymethylated nylon. Examples of the curable resin forming the three-dimensional network structure include polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy resin. Examples of the butyral resin include polyvinyl butyral.

The content of the binder resin is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10 to 200 parts by mass and more preferably 20 to 100 parts by mass with respect to 100 parts by mass of zinc oxide. ..

(Salicylic acid derivative)
The undercoat layer preferably contains a salicylic acid derivative. When the salicylic acid derivative is added to the undercoat layer coating liquid, zinc oxide is coated on the salicylic acid derivative. In the case of zinc oxide whose surface is not coated with anything, charge traps are likely to occur at the interface between the surface and the binder resin, and the exposed potential is likely to increase during repeated use, resulting in abnormal image density. Sometimes. In particular, when used in a high-temperature and high-humidity environment, charge traps may occur and an abnormality in image density may occur due to an increase in the exposed potential. When the surface of zinc oxide is coated with a salicylic acid derivative, these tend to be improved.

Examples of the salicylic acid derivative used in the present embodiment include the following. Salicylic acid, acetylsalicylic acid, 5-acetylsalicylic acid, 3-aminosalicylic acid, 5-acetylsalicylic acid, 5-aminosalicylic acid, 4-azidosalicylic acid, benzyl salicylate, 4-tert-butylphenyl salicylate, butyl salicylate, 3,5-di -T-butylsalicylic acid, 2-carboxyphenyl salicylic acid, 3,5-dinitrosalicylic acid, dithiosalicylic acid, ethyl acetylsalicylic acid, 2-ethylhexyl salicylate, ethyl 6-methylsalicylic acid, ethyl salicylate, 5-formylsalicylic acid, 4- (2-) Hydroxyethoxy) salicylic acid, 2-hydroxyethyl salicylate, isoamyl salicylate, isobutyl salicylate, isopropyl salicylate, 3-methoxysalicylic acid, 4-methoxysalicylic acid, 6-methoxysalicylic acid, methyl acetylsalicylate, 5-acetylsalicylate, 5-allyl-3 -Methyl methoxysalicylate, methyl 5-formylsalicylate, methyl 4- (2-hydroxyethoxy) salicylate, methyl 3-methoxysalicylic acid, methyl 4-methoxysalicylic acid, methyl 5-methoxysalicylic acid, methyl 4-methylsalicylic acid, 5-methylsalicylic acid Methyl, methyl salicylic acid, 3-methylsalicylic acid, 4-methylsalicylic acid, 5-methylsalicylic acid, methyl thiosalicylate, 4-nitrophenyl salicylate, 5-nitrosalicylic acid, 4-nitrosalicylic acid, 3-nitrosalicylic acid, 3,5-dinitro Salicylic acid, 4-octylphenyl salicylate, phenyl salicylate, 3-acetoxy-2-naphthanilide, 6-acetoxy-2-naphthoic acid, 3-amino-2-naphthoic acid, 6-amino-2-naphthoic acid, 1,4- Dihydroxy-2-naphthoic acid, 3,5-dihydroxy-2-naphthoic acid, 3,7-dihydroxy-2-naphthoic acid, 2-ethoxy-1-naphthoic acid, 2-hydroxy-1- (2-hydroxy-4) −Sulfo-1-naphthylazo) -3-naphthoic acid, 3-hydroxy-7-methoxy-2-naphthoic acid, 1-hydroxy-2-naphthoic acid, 2-hydroxy-1-naphthoic acid, 3-hydroxy-2- Naftoeic acid, 6-hydroxy-1-naphthoic acid, 6-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid hydrazide, 2-methoxy-1-naphthoic acid, 3-methoxy-2-naphthoic acid, 6 −methoxy-2-naphthoic acid, 6-amino-2-naphtho Methyl ate, methyl 3-hydroxy-2-naphthoate, methyl 6-hydroxy-2-naphthoate, methyl 3-methoxy-2-naphthoate, phenyl 1,4-dihydroxy-2-naphthoate, 1-hydroxy- Examples thereof include phenyl 2-naphthoate. These may be used alone, or two or more kinds may be mixed and used.

The content of the salicylic acid derivative is preferably 0.3% by mass or more and 6% by mass or less, more preferably 1.5% by mass or more and 4.0% by mass or less, and 1% by mass or more 3 with respect to zinc oxide. It is more preferably mass% or less. When the content of the salicylic acid derivative is 0.3% by mass or more with respect to zinc oxide, the function of the salicylic acid derivative can be sufficiently exhibited and good properties can be obtained. Further, when the content of the salicylic acid derivative is 6% by mass or less with respect to zinc oxide, sufficient characteristics can be obtained without causing inhibition of zinc oxide dispersion. These may be used alone or in combination of two or more.

(Other ingredients)
The undercoat layer may contain other components for the purpose of stabilizing electrical characteristics and image quality. The other components are not particularly limited and may be appropriately selected depending on the intended purpose. For example, electron transporting substances; electron transporting pigments such as polycyclic condensation type and azo type; silane coupling agents; zirconium chelating compounds; titanium chelating compounds; aluminum chelating compounds; fluorenone compounds; titanium alkoxide compounds; organic titanium compounds and the like. Can be mentioned. Other examples include antioxidants, plasticizers, lubricants, ultraviolet absorbers, leveling agents, etc., which will be described later. These may be used alone or in combination of two or more.

(Method of forming the undercoat layer)
The method for forming the undercoat layer is not particularly limited, and the undercoat layer can be formed by using an appropriate solvent and coating method. The time for adding the binder resin to the coating liquid for the undercoat layer used in the coating method may be before or after the dispersion of zinc oxide.

The solvent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the solvent include alcohol solvents, ketone solvents, ester solvents, ether solvents, halogen solvents, aromatic solvents, cellosolve solvents and the like. These may be used alone or in combination of two or more.

Examples of the alcohol solvent include methanol, ethanol, propanol, butanol and the like. Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and the like. Examples of the ester solvent include ethyl acetate and butyl acetate. Examples of the ether solvent include tetrahydrofuran, dioxane, propyl ether and the like.

Examples of the halogen-based solvent include dichloromethane, dichloroethane, trichloroethane, chlorobenzene and the like. Examples of the aromatic solvent include benzene, toluene, xylene and the like. Examples of the cellosolve solvent include methyl cellosolve, ethyl cellosolve, cellosolve acetate and the like.

The dispersion method of zinc oxide in the undercoat layer coating liquid is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the dispersion method include a dispersion method using a ball mill, a sand mill, a vibration mill, a KD mill, a three-roll mill, an attritor, a pressure homogenizer, ultrasonic dispersion, and the like.

The coating method is not particularly limited and may be appropriately selected depending on the viscosity of the coating liquid, the desired average thickness of the undercoat layer, and the like. For example, the dip coating method, the spray coating method, the bead coating method, and the ring coating method. And so on.

After coating with the undercoat layer coating liquid, it may be heated and dried in an oven or the like, if necessary. The drying temperature of the undercoat layer is not particularly limited and may be appropriately selected depending on the type of solvent contained in the coating liquid for the undercoat layer, but is preferably 80 ° C. to 200 ° C., preferably 100 ° C. ~ 150 ° C. is more preferable.

The average thickness of the undercoat layer is not particularly limited and can be appropriately selected depending on the electrical characteristics and life of the electrophotographic photosensitive member to be manufactured, but it may be adjusted to 30 μm or less, more preferably 10 to 20 μm. .. When the average thickness is 10 μm or more, charges having a polarity opposite to the charge polarity on the surface of the electrophotographic photosensitive member do not flow from the support into the photosensitive layer, and background stain-like image defects due to poor chargeability are unlikely to occur. On the other hand, when the average thickness is 20 μm or less, defects such as a decrease in light attenuation such as an increase in residual potential and a decrease in repeatability are less likely to occur.

As a method for measuring the average thickness, for example, a method of selecting an arbitrary plurality of points for the undercoat layer and calculating the average thickness of the plurality of points may be mentioned. As an average, the average of the thickness of 5 points is preferable, the average of the thickness of 10 points is more preferable, and the average of the thickness of 20 points is further preferable. The average thickness of the other layers can be calculated in the same manner.

Examples of the average thickness measuring device include a micrometer and the like.

The undercoat layer has a leak resistance function, a charge injection blocking function, and a charge transport function, and it is important that these characteristics do not change even with repeated electrostatic loads in order to obtain a stable photoconductor for a long period of time. Become.

The leak-resistant function means that the support is completely concealed by a homogeneous film. The charge injection blocking function means suppressing the injection of unnecessary charges (charges having the opposite polarity to the charge polarity of the photoconductor) from the support to the photosensitive layer. The charge transport function means to transport charges having the same polarity as the charge polarity of the photoconductor among the charges formed in the photosensitive layer.

In this respect, in the present embodiment, these characteristics can be achieved when the undercoat layer contains at least zinc oxide and a binder resin and the specular reflectance to incident light having a wavelength of 800 nm is 85% or more.

It is important that the undercoat layer is a dispersion film in which zinc oxide is uniformly dispersed. If zinc oxide agglomerates are present in the undercoat layer, these agglomerates become local leak points and cause abnormal images such as ground stains, and charge traps are generated in the agglomerates and the residual potential rises. It is possible that this may cause abnormal images such as afterimages.

In the present embodiment, the dispersibility of zinc oxide in the undercoat layer can be confirmed by the specular reflectance, and if the specular reflectance of the undercoat layer with respect to light having a wavelength of 800 nm is 85% or more, the zinc oxide is sufficiently dispersed. It can be said that it is in a state.

The specular reflectance can be measured by, for example, the following method. For example, for the photoconductor, the charge generation layer and the charge transport layer are dissolved or peeled off using a solvent, and a sample in which only the undercoat layer is laminated on the support is prepared. The dissolution or peeling of each layer can be performed by wiping the charge generation layer with a soft cloth (cotton) moistened with tetrahydrofuran, and immersing the charge transport layer in 2-butanone for a predetermined time.

Then, the specular reflectance of the undercoat layer at a wavelength of incident light of 800 nm and an incident light of 8 ° can be measured by using a measuring device for the obtained sample in which only the undercoat layer is laminated on the support. .. As the measuring device, for example, a spectrophotometer UV-3600 (manufactured by Shimadzu Corporation) equipped with a multipurpose large sample chamber unit MPC-3100 (manufactured by Shimadzu Corporation) can be used.

Next, a support in which nothing is laminated and a sample in which only the undercoat layer is laminated on the support are cut into an appropriate size. Then, after setting the support in which nothing is laminated on the measuring device and performing baseline correction, the sample in which only the undercoat layer is laminated on the support is set in the measuring device and the specular reflectance is measured. can do.

[Photosensitive layer]
The photosensitive layer may be a single-layer type photosensitive layer or a laminated type photosensitive layer.

(Single layer type photosensitive layer)
The single-layer photosensitive layer is a layer having both a charge generation function and a charge transport function at the same time. The single-layer photosensitive layer contains a charge generating substance, a charge transporting substance, and a binder resin, and further contains other components as required.

The charge generating substance is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the charge generating substance include monoazo pigments, disazo pigments, trisazo pigments, perylene pigments, perinone pigments, quinacridone pigments, quinone condensed polycyclic compounds, squalic acid dyes, phthalocyanine pigments, naphthalocyanine pigments, etc. Alternatively, azulenium salt dyes and the like can be mentioned. These charge generating substances may be used alone or in combination of two or more.

The content of the charge generating substance is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 5 parts by mass to 40 parts by mass with respect to 100 parts by mass of the binder resin.

The charge generating substance is preferably 0.1 to 30% by mass, more preferably 0.5 to 5% by mass, based on the entire photosensitive layer. When the concentration of the charge generating substance is low, the sensitivity of the photoconductor tends to decrease. On the other hand, when the concentration of the charge generating substance is high, the chargeability and the film strength tend to decrease.

The charge transporting substance is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include an electron transporting substance, a hole transporting substance, and a polymer charge transporting substance.

The electron transporting substance (electron accepting substance) is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the electron transporting substance include chloranyl, bromannyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2, 4,5,7-Tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophene-4-one, 1,3,7- Examples include electron-accepting substances such as trinitrodibenzothiophene-5,5-dioxide and benzoquinone derivatives. These electron transporting substances may be used alone or in combination of two or more.

Further, in the case of a single-layer type photosensitive layer, it is preferable to use the above-mentioned electron transporting substance together as the charge transporting substance in order to increase the sensitivity of the single-layering photosensitive layer.

The hole transporting substance (electron donating substance) is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the hole transporting substance include poly (N-vinylcarbazole) and its derivative, poly (γ-carbazolyl ethyl glutamate) and its derivative, pyrene-formaldehyde condensate and its derivative, polyvinylpyrene, polyvinylphenanthrene, and polysilane. , Oxazole derivative, Oxaziazole derivative, Imidazole derivative, Monoarylamine derivative, Diarylamine derivative, Triarylamine derivative, Stillben derivative, α-phenylstilben derivative, Aminobiphenyl derivative, Benzidine derivative, Diarylmethane derivative, Triarylmethane derivative , 9-Styrylanthracene derivative, pyrazoline derivative, divinylbenzene derivative, hydrazone derivative, inden derivative, butadiene derivative, pyrene derivative, bisstylben derivative, enamine derivative and the like. These charge transporting substances may be used alone or in combination of two or more.

The polymer charge transport material is a material having both the function of a binder resin and the function of a charge transport material. The polymer charge transporting substance is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the polymer charge transporting material include a polymer having a carbazole ring, a polymer having a hydrazone structure, a polysilylene polymer, a polymer having a triarylamine structure, a polymer having an electron donating group, and other polymers. And so on. Examples of the polymer having a triarylamine structure include the polymers having a triarylamine structure described in Japanese Patent No. 3852812 and Japanese Patent No. 3990499. These may be used alone or in combination of two or more.

Further, the polymer charge transporting substance may be used in combination with the binder resin in terms of abrasion resistance and film forming property.

The content of the charge transporting substance is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 20 to 300 parts by mass, more preferably 40 to 150 parts by mass with respect to 100 parts by mass of the binder resin. preferable.

The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose, and the same binder resin as that used in the laminated photosensitive layer described later can be used.

The other components are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a solvent, an antioxidant, a plasticizer, a lubricant, an ultraviolet absorber, and a leveling agent. The content of the other components is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.01% by mass to 10% by mass with respect to the total mass of the layer to be added.

The solvent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the solvent include tetrahydrofuran, dioxane, dioxolane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, cyclopentanone, anisole, xylene, methyl ethyl ketone, acetone, methyl acetate, ethyl acetate, butyl acetate, isopropanol, ethyl cell solve, etc. Examples include ligroine. The solvent is preferably a solvent that satisfactorily dissolves the charge transporting substance and the binder resin. These solvents may be used alone or in combination of two or more.

The plasticizer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include general resin plasticizers such as dibutyl phthalate and dioctyl phthalate.

(Method of forming a single-layer photosensitive layer)
The method for forming the single-layer photosensitive layer is not particularly limited and may be appropriately selected depending on the intended purpose. As a method for forming the single-layer type photosensitive layer, for example, a charge generating substance, a charge transporting substance, a binder resin, and other components are dissolved or dispersed in a solvent using a known dispersion method to obtain a coating. It can be formed by applying a working solution and drying it. As known dispersion methods, there are ball mills, attritors, sand mills, bead mills, ultrasonic waves and the like. The single-layer photosensitive layer is mainly composed of a charge generating substance, a charge transporting substance, a binder resin, and a solvent, but contains various additives such as a plasticizer, a leveling agent, and an antioxidant. May be good.

The method for applying the coating liquid is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a dip coating method, a spray coating method, a bead coating method and a ring coating method. Further, if necessary, a plasticizer, a leveling agent, an antioxidant and the like may be added.

The average thickness of the single-layer photosensitive layer is preferably 50 μm or less, and preferably 25 μm or less from the viewpoint of resolution and responsiveness. The lower limit value varies depending on the system used (particularly the charging potential), but is preferably 5 μm or more.

(Laminate type photosensitive layer)
The laminated photosensitive layer has at least a charge generating layer and a charge transporting layer, and the charge generating function and the charge transporting function are carried out by independent layers. In the laminated photosensitive layer, the stacking order of the charge generating layer and the charge transporting layer is not particularly limited and may be appropriately selected depending on the intended purpose. However, the charge transporting layer is laminated on the charge generating layer. Is preferable. This is because many charge generators have poor chemical stability, and when exposed to acid gases such as discharge products around the charger in the electrophotographic image formation process, the charge generation efficiency decreases. This is to suppress it. Next, the charge generation layer and the charge transport layer will be described.

(Charge generation layer)
The charge generating layer is a layer containing a charge generating substance. The charge generating layer preferably contains a charge generating substance and a binder resin, and further contains other components such as an antioxidant, if necessary.

As the charge generating substance, a substance similar to the charge generating substance used for the above-mentioned single-layer type photosensitive layer can be used.

The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the binder resin include polyamide resin, polyurethane resin, epoxy resin, polyketone resin, polycarbonate resin, silicone resin, acrylic resin, polyvinyl butyral resin, polyvinylformal resin, polyvinylketone resin, polystyrene resin, and poly-N-vinylcarbazole. Examples thereof include resins and polyacrylamide resins. These may be used alone or in combination of two or more.

The binding resin may be added either before or after dispersion.

In addition to the binder resin, a charge-transporting polymer material having a charge-transporting function may be included. Examples of the charge-transporting polymer material include polycarbonate, polyester, polyurethane, polyether, polysiloxane, and acrylic resin having an arylamine skeleton, a benzidine skeleton, a hydrazone skeleton, a carbazole skeleton, a stillben skeleton, a pyrazoline skeleton, and the like. A polymer material, a polymer material having a polysilane skeleton, or the like can be used.

The other components are not particularly limited and may be appropriately selected depending on the intended purpose. For example, low molecular weight charge transporting substances, solvents, antioxidants, plasticizers, lubricants, ultraviolet absorbers, leveling agents and the like. Can be mentioned.

The content of the other components is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.01% by mass to 10% by mass with respect to the total mass of the layer to be added.

The low-molecular-weight charge transporting substance is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include an electron transporting substance and a hole transporting substance. The electron transporting substance is not particularly limited and may be appropriately selected depending on the intended purpose. For example, chloranyl, bromannyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, etc. 2,4,5,7-Tetranitro-9-fluorenone, 2,4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1, 2-b] Thiophene-4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, diphenoquinone derivatives and the like can be mentioned. These may be used alone or in combination of two or more.

The hole transporting substance is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the hole transporting substance include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stillben derivatives, α-phenylstilben derivatives, benzidine derivatives, and diarylmethane derivatives. Examples thereof include triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazoline derivatives, divinylbenzene derivatives, hydrazone derivatives, inden derivatives, butadiene derivatives, pyrene derivatives, bisstylben derivatives, enamine derivatives and the like. These may be used alone or in combination of two or more.

As the solvent, the same solvent as the solvent used for the above-mentioned single-layer type photosensitive layer can be used.

The method for forming the charge generation layer is not particularly limited and may be appropriately selected depending on the intended purpose. As a method for forming the charge generating layer, for example, a charge generating substance, a binder resin, and other components are dissolved or dispersed in a solvent using a known dispersion method such as a ball mill, an attritor, a sand mill, or an ultrasonic wave. Then, the obtained coating liquid can be formed by applying it on a support and drying it. The charge generating layer is mainly composed of a charge generating substance, a solvent and a binder resin, but may contain various additives such as a sensitizer, a dispersant, a surfactant, and a silicone oil.

The method for applying the coating liquid is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the dipping coating method, the spray coating method, the bead coating method, the nozzle coating method, and the spinner coating method. , Ring coat method and the like.

The average thickness of the charge generation layer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.01 to 5 μm, more preferably 0.05 to 2 μm.

(Charge transport layer)
The charge transport layer is a layer for the purpose of retaining charged charges and moving and retaining the charged charges generated and separated in the charge generating layer by exposure. In order to achieve the purpose of retaining electric charge, high electrical resistance is required. Further, in order to achieve the purpose of obtaining a high surface potential with the retained charge, it is required that the dielectric constant is small and the charge transfer is good. The charge transport layer is a layer containing a charge transport substance. The charge transport layer preferably contains a binder resin, and further contains other components as needed.

As the charge transporting substance, the charge transporting substance used for the above-mentioned single-layer photosensitive layer can be similarly used.

The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the binder resin include polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyethylene resin, polyvinyl chloride resin, polyvinyl acetate resin, polystyrene resin, phenol resin, epoxy resin, polyurethane resin, and polyvinylidene chloride resin. Examples thereof include alkyd resin, silicone resin, polyvinylcarbazole resin, polyvinylbutyral resin, polyvinylformal resin, polyacrylate resin, polyacrylamide resin, and phenoxy resin. Of these, polycarbonate resin and polyarylate resin are preferable. These may be used alone or in combination of two or more. The charge transport layer may also contain a copolymer of a crosslinkable binder resin and a crosslinkable charge transport material.

The other components are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a solvent, an antioxidant, a plasticizer, a lubricant, an ultraviolet absorber, and a leveling agent.

The content of the other components is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.01% by mass to 10% by mass with respect to the total mass of the layer to be added.

As the solvent, the same solvent as that used in the above-mentioned single-layer photosensitive layer can be used, but a solvent that satisfactorily dissolves the charge transporting substance and the binder resin is preferable. These may be used individually by 1 type, or may be used by mixing 2 or more types.

As the plasticizer, the same plasticizer as that used in the above-mentioned single-layer photosensitive layer can be used.

The method for forming the charge transport layer is not particularly limited and may be appropriately selected depending on the intended purpose. As a method for forming the charge transport layer, for example, a charge transport substance, a binder resin, and other components are dissolved or dispersed in a solvent using a known dispersion method, and the obtained coating liquid is used as a charge generation layer. It can be formed by applying on top, heating and drying.

The coating method of the coating liquid used when forming the charge transport layer is not particularly limited, and can be appropriately selected depending on the purpose such as the viscosity of the coating liquid and the desired average thickness of the charge transport layer. .. Examples of the coating method of the coating liquid include a dip coating method, a spray coating method, a bead coating method, a nozzle coating method, a spinner coating method, and a ring coating method.

From the viewpoint of electrophotographic properties and film viscosity, the charge transport layer needs to remove the solvent from the inside of the charge transport layer by the following heating method. Examples of the heating method include a method of heating heat energy such as air, gas such as nitrogen, steam, various heat media, infrared rays, and electromagnetic waves from the coating surface side or the support side. The heating temperature is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 100 ° C to 170 ° C. When the heating temperature is 100 ° C. to 170 ° C., it becomes easy to sufficiently remove the solvent contained inside the charge transport layer. Therefore, deterioration of electrophotographic characteristics and wear resistance is less likely to occur, and it is possible to suppress yuzu-skin-like defects and cracks generated on the surface of the charge transport layer and peeling generated at the interface with the adjacent layer. As a result, even when the volatile components contained inside the photosensitive layer are atomized to the outside, it becomes easy to obtain desired electrical characteristics.

The average thickness of the charge transport layer is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of resolution and responsiveness, 50 μm or less is preferable, and 45 μm or less is more preferable. The lower limit of the average thickness of the charge transport layer depends on the system used (for example, charge potential), but is usually preferably 5 μm or more.

The content of the charge transporting substance with respect to the total mass of the charge transporting layer is not particularly limited and may be appropriately selected depending on the intended purpose. The content of the charge transporting substance is preferably 20% by mass to 80% by mass, more preferably 30% by mass to 70% by mass, from the viewpoint of easy availability of light attenuation and abrasion resistance on the surface of the electrophotographic photosensitive member. preferable. When the content is 20% by mass to 80% by mass, the charge transportability of the charge transport layer is not reduced and the desired light attenuation property can be easily obtained. In addition, it is possible to prevent the electrophotographic photosensitive member from being worn by various hazards during image formation, and to improve the durability of the electrophotographic photosensitive member. Further, when the content is 30% by mass to 70% by mass, it is advantageous in that a desired light attenuation property can be easily obtained, a wear amount is small, and a highly durable electrophotographic photosensitive member can be easily obtained.

[Other layers]
The other layers are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a protective layer (hereinafter, may be referred to as a surface layer).

(Protective layer)
The protective layer can be provided on the photosensitive layer for the purpose of improving the durability of the electrophotographic photosensitive member and improving other functions. The protective layer contains at least a binder resin and a filler, and further contains other components if necessary. By including the filler, the protective layer has high wear resistance and can achieve longer-term use of the electrophotographic photosensitive member.

The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the binder resin include AS resin, ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether resin, allyl resin, phenol resin, polyacetal resin, polyamide resin, polyamideimide resin, and polyacrylate resin. , Polyallyl sulfone resin, polybutylene resin, polybutylene terephthalate resin, polycarbonate resin, polyether sulfone resin, polyethylene resin, polyethylene terephthalate resin, polyimide resin, acrylic resin, polymethylpentene resin, polypropylene resin, polyphenylene oxide resin, polysulfone resin, Examples thereof include polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, and epoxy resin. These may be used individually by 1 type, or may be used by mixing 2 or more types. Among these, polycarbonate resin and polyacrylate resin are preferable from the viewpoint of filler dispersibility, residual potential, and coating film defects.

The filler is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include metal oxide particles. The metal oxide particles are not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the metal oxide particles include aluminum oxide, titanium oxide, silicon oxide, tin oxide, calcium oxide, barium sulfate, zinc oxide, antimony oxide, zirconium oxide, indium oxide, bismuth oxide, boron nitride, silicon nitride, colloidal silica. And so on. Other examples of the metal oxide particles include tin-doped indium oxide, antimony and tantalum-doped tin oxide, and antimony-doped zirconium oxide. Above all, from the viewpoint of the electrical characteristics of the protective layer, it is preferable to use aluminum oxide, titanium oxide, silicon oxide, and tin oxide. These may be used individually by 1 type, or may be used by mixing 2 or more types.

The average primary particle size of the filler is preferably in the range of 0.01 to 0.5 μm from the viewpoint of light transmittance and abrasion resistance of the protective layer. When the average primary particle size of the filler is 0.01 μm or more, deterioration of the wear resistance of the protective layer and the dispersibility of the filler in the protective layer can be suppressed. On the other hand, when the average primary particle size of the filler is 0.5 μm or less, it is possible to suppress an increase in the surface roughness of the protective layer, so that the wear of the blade cleaning member described later can be delayed. Therefore, it is possible to suppress the occurrence of poor toner cleaning and the promotion of sedimentation of the filler in the dispersion liquid depending on the specific gravity of the filler particles and the like.

As for the average particle size of the filler, 100 fillers observed in the protective layer are arbitrarily observed with a transmission electron microscope (TEM), the projected area is obtained, and the circle-equivalent diameter of the obtained area is calculated. The particle size was obtained, and the average value was taken as the average particle size.

The concentration of the filler material in the protective layer is usually 50% by mass or less, preferably 30% by mass or less, based on the total solid content. The higher the concentration of the filler material in the protective layer, the higher the abrasion resistance. However, if the concentration of the filler material in the protective layer is too high, the residual potential rises or the writing light of the protective layer is scattered and transmitted. The rate may decrease. When the concentration of the filler material in the protective layer is 50% by mass or less, the increase in the residual potential can be suppressed and the decrease in the transmittance can be suppressed.

The method for forming the protective layer is not particularly limited and can be formed by using an appropriate solvent and coating method as in the case of the photosensitive layer. For example, a dip coating method, a spray coating method, a bead coating method, or a nozzle coating method can be used. , Spinner coat method, ring coat method, etc.

The solvent used in the method for forming the protective layer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone and acetone. Be done.

As the solvent, a solvent having a high viscosity at the time of dispersing the binder resin or the filler and having a high volatility at the time of coating is preferable. When there is no solvent that satisfies these conditions, it is possible to use a mixture of two or more solvents having each physical property, which may have a great effect on the dispersibility and residual potential of the filler. is there.

Further, adding the charge transporting substance used for the charge transporting layer to the protective layer is effective and useful for reducing the residual potential and improving the image quality.

The average thickness of the protective layer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1 to 5 μm from the viewpoint of abrasion resistance.

<Aspects of electrophotographic photosensitive member>
Next, an embodiment of the electrophotographic photosensitive member according to the embodiment will be described.

[First aspect]
FIG. 1 shows an example of the layer structure of the electrophotographic photosensitive member according to the first aspect. FIG. 1 is a cross-sectional view showing an example of the configuration of an electrophotographic photosensitive member when the photosensitive layer is a single-layer type photosensitive layer. As shown in FIG. 1, the electrophotographic photosensitive member 10A is configured by laminating an undercoat layer 12 and a single-layer photosensitive layer 13A in this order on a support 11.

[Second aspect]
The electrophotographic photosensitive member according to the second aspect is obtained by changing the single-layer photosensitive layer of the electrophotographic photosensitive member according to the first aspect shown in FIG. 1 to a laminated photosensitive layer. FIG. 2 shows an example of the layer structure of the electrophotographic photosensitive member according to the second aspect. As shown in FIG. 2, the electrophotographic photosensitive member 10B changes the single-layer photosensitive layer 13A of the electrophotographic photosensitive member 10A shown in FIG. 1 to a laminated photosensitive layer 13B, and the laminated photosensitive layer 13B is an undercoat layer. The charge generation layer 15 and the charge transport layer 16 are laminated in this order on the 12th layer.

[Third aspect]
The electrophotographic photosensitive member according to the third aspect is the electrophotographic photosensitive member according to the first aspect shown in FIG. 1 provided with a protective layer. FIG. 3 shows an example of the layer structure of the electrophotographic photosensitive member according to the third aspect. As shown in FIG. 3, the electrophotographic photosensitive member 10C is configured by laminating a protective layer 17 on a single-layer photosensitive layer 13A of the electrophotographic photosensitive member 10A shown in FIG.

[Fourth aspect]
The electrophotographic photosensitive member according to the fourth aspect is the electrophotographic photosensitive member according to the second aspect shown in FIG. 2 provided with a protective layer. An example of the layer structure of the electrophotographic photosensitive member according to the fourth aspect is shown in FIG. As shown in FIG. 4, the electrophotographic photosensitive member 10D is configured by laminating a protective layer 17 on a laminated photosensitive layer 13B of the electrophotographic photosensitive member 10B shown in FIG.

<Image forming device>
The image forming apparatus according to the embodiment includes at least an electrophotographic photosensitive member, a charging unit, an exposure unit, a developing unit, and a transfer unit, and further includes other members, if necessary. The electrophotographic photosensitive member used in the image forming apparatus is the electrophotographic photosensitive member according to the above-described embodiment. The charged portion charges the surface of the electrophotographic photosensitive member. The exposed portion exposes the surface of the charged electrophotographic photosensitive member to form an electrostatic latent image. The developing unit develops the electrostatic latent image into a visible image with toner. The transfer unit transfers the visible image to a recording medium. In addition, the charged part and the exposed part may be collectively referred to as an electrostatic latent image forming part.

[Charging part]
The charged portion is not particularly limited and may be appropriately selected depending on the intended purpose. Examples include known contact chargers with conductive or semi-conductive rolls, brushes, films, rubber blades and the like. In addition, a non-contact charger using corona discharge such as a corotron or a scorotron (including a proximity type non-contact charger having a gap of 100 μm or less between the surface of the electrophotographic photosensitive member and the charger) can be mentioned.

The charged portion preferably has a charged member provided in contact with or close to the surface of the electrophotographic photosensitive member. Then, it is preferable to apply a voltage obtained by superimposing an AC component on a DC component to the charging member to form a corona discharge on the surface of the charging member and the electrophotographic photosensitive member to charge the surface of the electrophotographic photosensitive member.

[Exposure section]
The exposed portion is not particularly limited as long as the surface of the electrophotographic photosensitive member charged by the charged portion can be exposed in an image to be formed, and can be appropriately selected depending on the intended purpose. Examples of the exposure unit include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, a liquid crystal shutter optical system, and an LED optical system. Examples of the light source in the exposure device include a light source such as a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL) that can ensure high brightness. In this embodiment, an optical back surface method may be adopted in which the back surface side of the electrophotographic photosensitive member is exposed in an image manner.

[Development section]
The developing unit is not particularly limited and can be appropriately selected according to the purpose. For example, as long as it can be developed using toner or a developing agent, there is no particular limitation and it is appropriately selected according to the purpose. Can be done. The developing unit preferably has at least a developer that accommodates a developing agent and can apply the developing agent to the electrostatic latent image in contact or non-contact.

The developer may be a dry developing method or a wet developing method. Further, it may be a monochromatic developer or a multicolor developer. For example, those having a stirrer for frictionally agitating the developer to charge the developer and a rotatable magnet roller and the like are preferable.

In the developing device, for example, the toner and the carrier are mixed and agitated, and the toner is charged by the friction at that time and is held in a spiked state on the surface of the rotating magnet roller to form a magnetic brush. Since the magnet roller is arranged near the electrophotographic photosensitive member, a part of the toner constituting the magnetic brush formed on the surface of the magnet roller moves to the surface of the electrophotographic photosensitive member by an electric attraction force. .. As a result, the electrostatic latent image is developed by the toner and a visible image by the toner is formed on the surface of the electrophotographic photosensitive member.

[Transfer section]
The transfer unit is a unit that transfers a visible image to a recording medium, and is visible on the intermediate transfer body by using a method of directly transferring the visible image from the surface of the electrophotographic photosensitive member to the recording medium and an intermediate transfer body. After the primary transfer of the image, there is a method of secondary transfer of the visible image onto a recording medium. Any aspect can be used satisfactorily, but when the adverse effect of transfer is large in improving the image quality, the former method (direct transfer) in which the number of transfers is small is preferable. The transfer can be performed, for example, by charging the electrophotographic photosensitive member with a transfer charger for a visible image, and can be performed by a transfer unit.

[Other means]
The other means are not particularly limited and may be appropriately selected depending on the purpose. Examples of other means include a fixing unit, a static elimination unit, a cleaning unit, a recycling unit, a control unit, and the like.

(Fixing part)
The fixing portion is not particularly limited and may be appropriately selected depending on the intended purpose, but a known heating and pressurizing portion is preferable. Examples of the heating and pressurizing unit include a combination of a heating roller and a pressurizing roller, a combination of a heating roller, a pressurizing roller, and an endless belt. The heating in the heating and pressurizing section is usually preferably 80 to 200 ° C. The fixing may be performed, for example, every time the toner of each color is transferred to the recording medium, or the toner of each color may be laminated at the same time at the same time.

(Static elimination unit)
The static elimination unit is not particularly limited as long as it can apply a static elimination bias to the electrophotographic photosensitive member, and can be appropriately selected from known static elimination devices. For example, a static elimination lamp and the like are preferable. ..

(Cleaning department)
The cleaning unit is not particularly limited as long as it can remove the electrophotographic toner remaining on the electrophotographic photosensitive member, and can be appropriately selected from known cleaners. Suitable examples of the cleaning unit include a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, a brush cleaner, and a web cleaner.

(Recycling Department)
The recycling unit is not particularly limited, and examples thereof include known transportation means.

(Control unit)
The control unit is not particularly limited as long as it can control the movement of each of the above configurations, and can be appropriately selected depending on the intended purpose. Examples thereof include devices such as sequencers and computers.

[One aspect of the image forming apparatus]
An aspect of the image forming apparatus according to the embodiment will be described. FIG. 5 is a schematic view showing an example of the vicinity of the electrophotographic photosensitive member in the image forming apparatus according to the embodiment. In FIG. 5, the electrophotographic photosensitive member 10A according to the embodiment is used as the electrophotographic photosensitive member, but the electrophotographic photosensitive member 10B to 10D may also be used. As shown in FIG. 5, the image forming apparatus 20 includes an electrophotographic photosensitive member 10A, a charging unit 21, an exposure unit 22, a developing unit 23, and a transfer unit 24. In the image forming apparatus 20, the electrophotographic photosensitive member 10A is rotated in a counterclockwise direction, and the charging portion 21, the exposure section 22, the developing section 23, and the transfer section 24 are around the electrophotographic photosensitive member 10A. Etc. are arranged.

The charging unit 21 charges the electrophotographic photosensitive member 10A on average. As the charging unit 21, for example, a corotron device, a scorotron device, a solid discharge element, a needle electrode device, a roller charging device, a conductive brush device, or the like is used, and known means can be used.

In particular, the configuration of the image forming apparatus according to the embodiment uses a charged portion such as a contact charging method or a non-contact close placement charging method that causes a proximity discharge from a charged portion that causes decomposition of the photoconductor composition. Especially effective in some cases.

The contact charging method is a charging method in which a charging roller, a charging brush, a charging blade, or the like is in direct contact with the photoconductor. The proximity charging method is, for example, a method in which the charging rollers are arranged in close contact with each other so as to have a gap of, for example, 200 μm or less between the surface of the photoconductor and the charged portion. If this void is too large, charging tends to be unstable, and if it is too small, the surface of the charged member may be contaminated in the presence of toner remaining on the photoconductor. There is. Therefore, the air gap is preferably in the range of 10 to 200 μm, preferably 10 to 100 μm.

The exposed unit 22 forms an electrostatic latent image on the surface of the uniformly charged electrophotographic photosensitive member 10A. As the light source of the exposure unit 22, for example, a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), an electroluminescence (EL), or the like can be used in general. it can. Various filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can also be used to irradiate only light in a desired wavelength range.

The developing unit 23 develops an electrostatic latent image formed on the surface of the electrophotographic photosensitive member 10A into a toner image visualized with toner. Examples of the developing method include a one-component developing method using a dry toner, a two-component developing method, and a wet developing method using a wet toner. When the electrophotographic photosensitive member 1 is positively (negatively) charged and image-exposed, a positive (negative) electrostatic latent image is formed on the surface of the electrophotographic photosensitive member. When this is developed with a negative (positive) polarity toner (electrostatic fine particles), a positive image is obtained, and when it is developed with a positive (negative) polarity toner, a negative image is obtained.

The transfer unit 24 transfers the toner image (visible image) visualized on the surface of the electrophotographic photosensitive member 10A to the recording medium 26 thrown by the roller 25. In addition, a pre-transfer charger 27 may be used in order to perform better transfer. As the transfer unit 24, an electrostatic transfer method using a transfer charger, a bias roller, or the like; a mechanical transfer method such as an adhesive transfer method or a pressure transfer method; a magnetic transfer method or the like can be used. As the electrostatic transfer method, a charged portion can be used.

Further, if necessary, a separation charger 28 and a separation claw 29 may be used as a method for separating the recording medium 26 from the electrophotographic photosensitive member 10A. As other separation methods, electrostatic adsorption induction separation, side end belt separation, tip grip transfer, curvature separation and the like are used. As the separation charger 28, the same method as the charging unit can be used.

Further, in order to clean the toner left on the surface of the electrophotographic photosensitive member 10A after the transfer, a cleaning unit such as a fur brush 30 and a cleaning blade 31 is used. Moreover, in order to perform cleaning more efficiently, the pre-cleaning charger 32 may be used. Other cleaning methods include a web method and a magnet brush method, but each method may be used alone or in combination.

Further, if necessary, the static eliminator 33 may be used to remove the electrostatic latent image on the surface of the electrophotographic photosensitive member 10A. As the static eliminator 33, a static eliminator lamp, a static eliminator, and the like are used, and the light source and the charging section 21 of the exposed section 22 can be used, respectively.

In addition, known processes such as document reading, paper feeding, fixing, and paper ejection that are not close to the electrophotographic photosensitive member 10A can be used.

The charging unit, the exposure unit, the developing unit, the transfer unit, and the like in the image forming apparatus described above may be fixedly incorporated in the copying apparatus, the facsimile, or the printer, but are incorporated in the apparatus in the form of a process cartridge. It may be removable.

<Process cartridge>
The process cartridge according to the embodiment includes an electrophotographic photosensitive member and at least one of a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a static elimination unit, and if necessary, other means. Must have.

The charged portion charges the surface of the electrophotographic photosensitive member. The exposed portion exposes the surface of the charged electrophotographic photosensitive member to form an electrostatic latent image. The developing unit develops the electrostatic latent image into a visible image with toner. The transfer unit transfers the visible image to a recording medium. The electrophotographic photosensitive member used in the process cartridge according to the embodiment is the electrophotographic photosensitive member according to the above-described embodiment.

[One aspect of process cartridge]
One aspect of the process cartridge according to the embodiment will be described. FIG. 6 is a schematic view showing an example of the process cartridge according to the embodiment. As shown in FIG. 6, the process cartridge 40 includes an electrophotographic photosensitive member 10A, a charging unit 41, an exposure unit 42, a developing unit 43, a transfer unit 44, a cleaning unit 45, and a static elimination unit (not shown), and is an image forming apparatus. It is detachably attached to the main body of.

Explaining the image forming process using the process cartridge, the electrophotographic photosensitive member 10A is charged by the charging unit 41 while rotating in the direction of the arrow in FIG. 6, and then exposed to the exposure unit 42 to be electrostatically charged on the surface. A latent image is formed. The electrostatic latent image is developed into a toner image by the developing unit 43, and the toner image is transferred to the recording medium 46 by the transfer unit 44 and output (printed out). After the toner image is transferred to the recording medium 46, the surface of the electrophotographic photosensitive member 10A is cleaned by the cleaning unit 45, and further statically eliminated by the static elimination unit (not shown). In the process cartridge 40, the above operation is repeated again.

Although the embodiments have been described above, the above embodiments are presented as examples, and the present invention is not limited to the above embodiments. The above-described embodiment can be implemented in various other forms, and various combinations, omissions, replacements, changes, etc. can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

Hereinafter, embodiments will be described in more detail with reference to Examples and Comparative Examples, but the embodiments are not limited to these Examples. In addition, "part" means all parts by mass.

<Manufacturing of Al alloy support (Al alloy cylinder)>
An aluminum alloy was prepared, and the aluminum alloy was DC-cast to prepare an aluminum alloy column (billet). The prepared billet was processed into a circular tube having a cross section as shown in FIG. 5 by hot extrusion. The same die was used for all extrusions. During extrusion processing, no abnormalities such as dimensional defects or inability to extrude were confirmed. This pipe was cut to a length of 380 mm to prepare a crude pipe to be used for cutting. The crude tube thus produced was attached to a lathe and the surface was machined to produce 10 Al alloy supports (Al alloy cylinders) having an outer diameter of 60 mm and a surface roughness Rz of 1.2 μm.

As the Al alloy, Al alloys a-1 to a-7 and b-1 to b-6 shown in Table 1 below were used. The Al alloy cylinders obtained by using the Al alloys a-1 to a-7 and b-1 to b-6 were designated as Al alloy cylinders A-1 to A-7 and B-1 to B-6. The Al alloys a-1 to a-7 are included in the range of the components of the aluminum alloy used for the support of the electrophotographic photosensitive member according to the present embodiment. On the other hand, the Al alloys b-1 to b-6 are not included in the range of the components of the aluminum alloy used for the support of the electrophotographic photosensitive member according to the present embodiment. Further, the Al alloy cylinders A-1 to A-7 are included in the support of the electrophotographic photosensitive member according to the present embodiment. On the other hand, the Al alloy cylinders B-1 to B-6 are not included in the support of the electrophotographic photosensitive member according to the present embodiment.

Table 1 shows the content of each component contained in the aluminum alloys a-1 to a-7 and b-1 to b-6.

<Adjustment of undercoat layer coating liquid>
(Adjustment of undercoat layer coating liquid 1)
The following materials were mixed and stirred at 1,500 rpm for 6 hours using zirconia beads having a diameter of 0.5 mm and a vibration mill to prepare an undercoat layer coating liquid 1.
-Zinc oxide (MZ-300, manufactured by Teika Co., Ltd., average particle size 35 μm) 350 parts-Salicylic acid derivative: 3,5-di-t-butylsalicylic acid (manufactured by TCI-D1947 Tokyo Kasei Co., Ltd.) 1.5 parts-Binding resin:
Blocked isocyanate (Sumijour BL3175, solid content concentration 75% by mass, manufactured by Sumika Bayer Urethane) 60 parts 20% by mass diluted solution of butyral resin (BM-S, manufactured by Sekisui Chemical Co., Ltd.) dissolved in 2-butanone. 225 parts, solvent: 2-butanone 105 parts

(Adjustment of undercoat layer coating liquid 2)
The undercoat layer coating liquid 2 was prepared in the same manner as the undercoat layer coating liquid 1 except that the material used in the undercoat layer coating liquid 1 was changed to the following material.
-Zinc oxide (MZ-300, manufactured by TAYCA CORPORATION, average particle diameter 35 μm) 350 parts-Bundling resin:
Blocked isocyanate (Sumijour BL3175, solid content concentration 75% by mass, manufactured by Sumika Bayer Urethane Co., Ltd.) 60 parts 20% by mass diluted solution of butyral resin (BM-S, manufactured by Sekisui Chemical Co., Ltd.) dissolved in 2-butanone 225 Part / Solvent: 2-butanone 105 parts

(Adjustment of undercoat layer coating liquid 3)
The undercoat layer coating liquid 3 was prepared in the same manner as the undercoat layer coating liquid 1 except that the material used in the undercoat layer coating liquid 1 was changed to the following material.
-Zinc oxide: (MZ-300, manufactured by Teika Co., Ltd., average particle size 35 μm) 350 parts-Salicylic acid derivative: 3-aminosalicylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 1.5 parts-Bundling resin:
Blocked isocyanate (Sumijour BL3175, solid content concentration 75% by mass, manufactured by Sumika Bayer Urethane Co., Ltd.) 60 parts 20% by mass diluted solution of butyral resin (BM-S, manufactured by Sekisui Chemical Co., Ltd.) dissolved in 2-butanone 225 Part / Solvent: 2-butanone 105 parts

(Adjustment of undercoat layer coating liquid 4)
The undercoat layer coating liquid 4 was prepared in the same manner as the undercoat layer coating liquid 1 except that the material used in the undercoat layer coating liquid 1 was changed to the following material.
-Zinc oxide (MZ-300, manufactured by TAYCA Corporation, average particle size 35 μm) 350 parts-Salicylic acid derivative: 3,5-dinitrosalicylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 1.5 parts-Bundling resin:
Blocked isocyanate (Sumijour BL3175, solid content concentration 75% by mass, manufactured by Sumika Bayer Urethane Co., Ltd.) 60 parts 20% by mass diluted solution of butyral resin (BM-S, manufactured by Sekisui Chemical Co., Ltd.) dissolved in 2-butanone 225 Part / Solvent: 2-butanone 105 parts

(Adjustment of undercoat layer coating liquid 5)
The undercoat layer coating liquid 5 was prepared in the same manner as the undercoat layer coating liquid 1 except that the material used in the undercoat layer coating liquid 1 was changed to the following material.
-Titanium oxide particles (MT-500B, manufactured by TAYCA Corporation, average particle diameter 35 μm) 350 parts-Bundling resin:
Blocked isocyanate (Sumijour BL3175, solid content concentration 75% by mass, manufactured by Sumika Bayer Urethane Co., Ltd.) 60 parts 20% by mass diluted solution of butyral resin (BM-S, manufactured by Sekisui Chemical Co., Ltd.) dissolved in 2-butanone 225 Part / Solvent: 2-butanone 105 parts

(Adjustment of undercoat layer coating liquid 6)
The undercoat layer coating liquid 6 was prepared in the same manner as the undercoat layer coating liquid 1 except that the material used in the undercoat layer coating liquid 1 was changed to the following material.
-Zinc oxide: (MZ-300, manufactured by Teika Co., Ltd., average particle size 35 μm) 350 parts-Salicylic acid derivative: 3-aminosalicylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 1.5 parts-Bundling resin:
Blocked isocyanate (Sumijour BL3175, solid content concentration 75% by mass, manufactured by Sumika Bayer Urethane Co., Ltd.) 60 parts 20% by mass diluted solution of butyral resin (BM-S, manufactured by Sekisui Chemical Co., Ltd.) dissolved in 2-butanone 225 Part / Solvent: 2-butanone 105 parts

(Adjustment of undercoat layer coating liquid 7)
The undercoat layer coating liquid 7 was prepared in the same manner as the undercoat layer coating liquid 1 except that the material used in the undercoat layer coating liquid 1 was changed to the following material.
-Zinc oxide: (MZ-300, manufactured by TAYCA CORPORATION, average particle diameter 35 μm) 350 parts-Bundling resin:
Blocked isocyanate (Sumijour BL3175, solid content concentration 75% by mass, manufactured by Sumika Bayer Urethane Co., Ltd.) 60 parts 20% by mass diluted solution of butyral resin (BM-S, manufactured by Sekisui Chemical Co., Ltd.) dissolved in 2-butanone 225 Part / Solvent: 2-butanone 105 parts

(Adjustment of undercoat layer coating liquid 8)
The undercoat layer coating liquid 8 was prepared in the same manner as the undercoat layer coating liquid 1 except that the material used in the undercoat layer coating liquid 1 was changed to the following material.
-Titanium oxide particles (MT-500B, manufactured by TAYCA Corporation, average particle diameter 35 μm) 350 parts-Bundling resin:
Blocked isocyanate (Sumijour BL3175, solid content concentration 75% by mass, manufactured by Sumika Bayer Urethane Co., Ltd.) 60 parts 20% by mass diluted solution of butyral resin (BM-S, manufactured by Sekisui Chemical Co., Ltd.) dissolved in 2-butanone 225 Part / solvent: 2-butanone

(Adjustment of undercoat layer coating liquid 9)
The undercoat layer coating liquid 9 was prepared in the same manner as the undercoat layer coating liquid 1 except that the material used in the undercoat layer coating liquid 1 was changed to the following material.
-Titanium oxide particles (MT-500B, manufactured by TAYCA Corporation, average particle diameter 35 μm) 350 parts-Bundling resin:
Blocked isocyanate (Sumijour BL3175, solid content concentration 75% by mass, manufactured by Sumika Bayer Urethane Co., Ltd.) 60 parts 20% by mass diluted solution of butyral resin (BM-S, manufactured by Sekisui Chemical Co., Ltd.) dissolved in 2-butanone 225 Part / solvent: 2-butanone

(Adjustment of undercoat layer coating liquid 10)
The undercoat layer coating liquid 10 was prepared in the same manner as the undercoat layer coating liquid 1 except that the material used in the undercoat layer coating liquid 1 was changed to the following material.
-Titanium oxide particles (MT-500B, manufactured by TAYCA Corporation, average particle diameter 35 μm) 350 parts-Salicylic acid derivative: 3,5-dinitrosalicylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 1.5 parts-Bundling resin:
Blocked isocyanate (Sumijour BL3175, solid content concentration 75% by mass, manufactured by Sumika Bayer Urethane Co., Ltd.) 60 parts 20% by mass diluted solution of butyral resin (BM-S, manufactured by Sekisui Chemical Co., Ltd.) dissolved in 2-butanone 225 Part / Solvent: 2-butanone 105 parts

(Adjustment of undercoat layer coating liquid 11)
The material used in the undercoat layer coating liquid 1 was changed to the following material, and the undercoat layer coating was performed in the same manner as the undercoat layer coating liquid 1 except that the stirring time in the vibration mill was changed to 3 hours. Liquid 11 was prepared.
-Zinc oxide (MZ-300, manufactured by Teika Co., Ltd., average particle size 35 μm) 350 parts-Salicylic acid derivative: 3,5-di-t-butylsalicylic acid (manufactured by TCI-D1947 Tokyo Kasei Co., Ltd.) 1.5 parts-Binding resin:
Blocked isocyanate (Sumijour BL3175, solid content concentration 75% by mass, manufactured by Sumika Bayer Urethane Co., Ltd.) 60 parts 20% by mass diluted solution of butyral resin (BM-S, manufactured by Sekisui Chemical Co., Ltd.) dissolved in 2-butanone 225 Part / Solvent: 2-butanone 105 parts

(Adjustment of undercoat layer coating liquid 12)
The material used in the undercoat layer coating liquid 1 was changed to the following material, and the undercoat layer coating was performed in the same manner as the undercoat layer coating liquid 1 except that the stirring time in the vibration mill was changed to 5 hours. Liquid 12 was prepared.
-Zinc oxide (MZ-300, manufactured by Teika Co., Ltd., average particle size 35 μm) 350 parts-Salicylic acid derivative: 3,5-di-t-butylsalicylic acid (manufactured by TCI-D1947 Tokyo Kasei Co., Ltd.) 1.5 parts-Binding resin:
Blocked isocyanate (Sumijour BL3175, solid content concentration 75% by mass, manufactured by Sumika Bayer Urethane Co., Ltd.) 60 parts 20% by mass diluted solution of butyral resin (BM-S, manufactured by Sekisui Chemical Co., Ltd.) dissolved in 2-butanone 225 Part solvent: 2-butanone

<Adjustment of charge generation layer coating liquid>
The following materials were mixed and stirred for 8 hours using glass beads having a diameter of 1 mm and a bead mill to prepare a charge generation layer coating liquid.
・ Titanyl phthalocyanine: 8 parts ・ Polyvinyl butyral (BX-1, manufactured by Sekisui Chemical Co., Ltd.): 5 parts ・ 2-Butanone: 400 parts

<Adjustment of charge transport layer coating liquid>
The following materials were mixed and prepared by stirring with a stirrer for 3 hours until all the materials were dissolved.
-Charge transport material: 10 parts of the charge transport material of the following structural formula (1)

・ Bundling resin: Bisphenol Z type polycarbonate (Panlite TS-2050, manufactured by Teijin Co., Ltd.) 10 parts ・ Leveling agent: 1% silicone oil (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.) in tetrahydrofuran solution 0.2 part ・ Solvent: 80 parts of tetrahydrofuran

<Adjustment of protective layer coating liquid>
The following materials were mixed and prepared by stirring with a stirrer for 3 hours until all the materials were dissolved.
-Radical polymerizable monomer (trimethylolpropane acrylate) (KAYARAD TMPTA, manufactured by Nippon Kayaku Co., Ltd.) 10 parts 10 parts of the compound of the following structural formula (2)

Photopolymerization initiator (Irgacure 184, manufactured by Ciba Specialty Chemicals) 1 part Solvent: 100 parts tetrahydrofuran

<Preparation of electrophotographic photosensitive member>
[Example 1]
Using the Al alloy cylinder A-1 which is an Al alloy support, the above-mentioned undercoat layer coating liquid 1 is applied onto the Al alloy cylinder A-1 by the dip coating method, and then dried at 170 ° C. for 30 minutes. To form an undercoat layer having an average thickness of 20 μm.

Next, the above charge generation layer coating solution was applied onto the undercoat layer by a dip coating method, and then heat-dried at 90 ° C. for 20 minutes to laminate a charge generation layer having an average thickness of 0.2 μm.

Next, the above charge transport layer coating liquid was applied onto the obtained charge generation layer by an immersion coating method, and then heat-dried at 120 ° C. for 20 minutes to laminate a charge transport layer having an average thickness of 25 μm. did.

The above protective layer coating solution was spray-coated on the obtained charge transport layer, and light was irradiated with a metal halide lamp (irradiation intensity: 500 mW / cm ² , irradiation time: 160 seconds). Further, it was dried at 130 ° C. for 30 minutes, and a protective layer having an average thickness of 4.0 μm was laminated. As a result, an electrophotographic photosensitive member was obtained.

[Example 2, Comparative Examples 1 and 2]
Except that the Al alloy cylinder A-1 of Example 1 was changed to Al alloy cylinder A-2 in Example 2, Al alloy cylinder B-1 in Comparative Example 1, and Al alloy cylinder B-2 in Comparative Example 2. , An electrophotographic photosensitive member was obtained in the same manner as in Example 1.

[Example 3]
An electrophotographic photosensitive member was obtained by the same method as in Example 1 except that the thickness of the undercoat layer of Example 1 was changed to 10 μm.

[Example 4]
An electrophotographic photosensitive member was obtained by the same method as in Example 1 except that the Al alloy cylinder A-1 of Example 1 was replaced with an Al alloy cylinder A-3 and the thickness of the undercoat layer was changed to 15 μm.

[Example 5]
An electrophotographic photosensitive member was obtained by the same method as in Example 1 except that the Al alloy cylinder A-1 of Example 1 was changed to the Al alloy cylinder A-4 and the thickness of the undercoat layer was changed to 7 μm.

[Example 6]
An electrophotographic photosensitive member was obtained by the same method as in Example 1 except that the Al alloy cylinder A-1 of Example 1 was changed to Al alloy cylinder A-5 and the thickness of the undercoat layer was changed to 23 μm.

[Example 7]
The Al alloy cylinder A-1 of Example 1 was changed to the Al alloy cylinder A-6, the undercoat layer coating liquid 1 was changed to the above undercoat layer coating liquid 2, and the thickness of the undercoat layer was changed to 10 μm. An electrophotographic photosensitive member was obtained by the same method as in Example 1 except for the above.

[Example 8]
The Al alloy cylinder A-1 of Example 1 was changed to the Al alloy cylinder A-7, the undercoat layer coating liquid 1 was changed to the above undercoat layer coating liquid 3, and the thickness of the undercoat layer was changed to 10 μm. An electrophotographic photosensitive member was obtained by the same method as in Example 1 except for the above.

[Example 9]
The undercoat layer coating liquid 1 of Example 1 was changed to the above-mentioned undercoat layer coating liquid 4, and the film thickness of the undercoat layer was changed to 10 μm, but the electrograph was performed by the same method as in Example 1. A photoconductor was obtained.

[Comparative Example 3]
Same as in Example 1 except that the Al alloy cylinder A-1 of Example 1 was changed to the Al alloy cylinder B-3 and the undercoat layer coating liquid 1 was changed to the above undercoat layer coating liquid 5. An electrophotographic photosensitive member was obtained by the above method.

[Comparative Example 4]
The Al alloy cylinder A-1 of Example 1 was changed to the Al alloy cylinder B-4, the undercoat layer coating liquid 1 was changed to the above undercoat layer coating liquid 6, and the thickness of the undercoat layer was 23 μm. An electrophotographic photosensitive member was obtained by the same method as in Example 1 except that it was changed to.

[Comparative Example 5]
The Al alloy cylinder A-1 of Example 1 was changed to the Al alloy cylinder B-5, the undercoat layer coating liquid 1 was changed to the above undercoat layer coating liquid 7, and the thickness of the undercoat layer was 7 μm. An electrophotographic photosensitive member was obtained by the same method as in Example 1 except that it was changed to.

[Comparative Example 6]
An electrophotographic photosensitive member was obtained by the same method as in Example 1 except that the Al alloy cylinder A-1 of Example 1 was changed to an Al alloy cylinder B-6 and the thickness of the undercoat layer was changed to 15 μm. It was.

[Comparative Example 7]
By the same method as in Example 1 except that the undercoat layer coating liquid 1 used in Example 1 was changed to the above undercoat layer coating liquid 8 and the film thickness of the undercoat layer was changed to 30 μm. , An electrophotographic photosensitive member was obtained.

[Comparative Example 8]
The Al alloy cylinder A-1 of Example 1 was changed to the Al alloy cylinder A-2, the undercoat layer coating liquid 1 was changed to the above undercoat layer coating liquid 9, and the thickness of the undercoat layer was increased to 5 μm. An electrophotographic photosensitive member was obtained by the same method as in Example 1 except that it was changed.

[Comparative Example 9]
By the same method as in Example 1, except that the undercoat layer coating liquid 1 used in Example 1 was changed to the above undercoat layer coating liquid 10 and the thickness of the undercoat layer was changed to 35 μm. An electrophotographic photosensitive member was obtained.

[Comparative Example 10]
The Al alloy cylinder A-1 of Example 1 was changed to the Al alloy cylinder A-4, the undercoat layer coating liquid 1 was changed to the above undercoat layer coating liquid 11, and the thickness of the undercoat layer was changed to 10 μm. An electrophotographic photosensitive member was obtained in the same manner as in Example 1 except that the changes were made.

[Comparative Example 11]
The Al alloy cylinder A-1 of Example 1 was changed to the Al alloy cylinder A-5, the undercoat layer coating liquid 1 was changed to the above undercoat layer coating liquid 12, and the average thickness of the undercoat layer was 10 μm. An electrophotographic photosensitive member was obtained in the same manner as in Example 1 except that it was changed to.

<Measurement of specular reflectance of the undercoat layer>
For each electrophotographic photosensitive member, a sample was prepared in which the charge generation layer and the charge transport layer were dissolved or peeled off using a solvent, and only the undercoat layer was laminated on the support. The dissolution or peeling of each layer was carried out by wiping the charge generation layer with a soft cloth (cotton) moistened with tetrahydrofuran, and immersing the charge transport layer in 2-butanone for a predetermined time. The specular reflectance of each undercoat layer at a wavelength of incident light of 800 nm and an incident light of 8 ° was measured using a measuring device for a sample in which only the obtained undercoat layer was laminated on the support. As a measuring device, a spectrophotometer UV-3600 (manufactured by Shimadzu Corporation) equipped with a multipurpose large sample chamber unit MPC-3100 (manufactured by Shimadzu Corporation) was used.

Specifically, a sample in which only the support having nothing laminated and the undercoat layer was laminated on the support was cut into an appropriate size. Then, after setting the support in which nothing is laminated on the measuring device and performing baseline correction, the sample in which only the undercoat layer is laminated on the support is set in the measuring device, and the undercoat layer is set. The specular reflectance of the above was measured.

<Evaluation of characteristics of electrophotographic photosensitive member>
[Evaluation device]
A modified digital copier (ProC900, manufactured by Ricoh Co., Ltd.) was used, and a scorotron-type charging member (the discharge wire was a tungsten-molybdenum alloy plated with gold with a diameter of 50 μm) was used as the charging member. Further, LD light of 780 nm (image writing by a polygon mirror, resolution of 1,200 dpi) was used as an image exposure light source. Two-component development was performed using black toner, a transfer belt was used as a transfer member, and a static elimination lamp was used for static elimination.

[Degradation test of electrophotographic photosensitive member]
In a high-temperature and high-humidity environment (HH) with a relative humidity of 80% RH at 27 ° C., 500,000 sheets of a black monochromatic test chart with an image area ratio of 5% are continuously output to an electrophotographic photosensitive member using an evaluation device. The load was applied. The image area ratio of 5% means that characters equivalent to 5% as an image area are written on the entire surface of A4 on average.

<Evaluation of image quality: Evaluation of color spots and background stains>
Before and after the deterioration test of the electrophotographic photosensitive member, five sheets of white background images were continuously output (printed) using gloss coated paper, and color spots and background stains were evaluated as image quality evaluations. Of the output gloss-coated paper, the number of color spots and background stains that could be visually confirmed at 10 arbitrary 8 mm × 11 mm visual fields was counted, and the average was calculated. From the calculation result of the number of color spots and ground stains, the evaluation of color spots and ground stains was performed by classifying them into one of double circles, circles, and crosses as follows.
(Color spot)
◎: 1 or less ○: 1 or more, 2 or less ×: 2 or more (ground stain)
⊚: 10 or less ○: 10 or more, 20 or less ×: 20 or more

Table 2 shows the types of Al alloy cylinders and the configuration of the undercoat layer used for the electrophotographic photosensitive member in each of the above Examples and Comparative Examples, and the evaluation results of the electrophotographic photosensitive member in each of the above Examples and Comparative Examples. Shown.

From Table 2, the electrophotographic photosensitive members of Examples 1 to 9 use Al alloy cylinders A-1 to A-7 having a predetermined composition as a support, even in a high temperature and high humidity environment. It was confirmed that stable image quality was obtained for a long period of time. In particular, it was confirmed that color spot-like stains could be reduced. Further, it was confirmed that the ground pollution can be further reduced by setting the thickness of the undercoat layer to 10 to 20 μm or by containing salicylic acid (see Examples 1 to 4, 8 and 9). Therefore, by using Al alloy cylinders A-1 to A-7 having a predetermined composition as a support and further setting the thickness of the undercoat layer within a predetermined range or containing salicylic acid, color spot-like stains and ground are formed. It can be said that both stains can be improved.

On the other hand, when the electrophotographic photosensitive members of Comparative Examples 1 to 6 were used for a long period of time in a high temperature and high humidity environment, it was confirmed that color spot-like stains were generated after the deterioration test and the image quality was not stable. It can be said that this is because the electrophotographic photosensitive member does not use an Al alloy cylinder having a predetermined composition as a support.

Further, it was confirmed that when the electrophotographic photosensitive members of Comparative Examples 7 to 11 were used for a long period of time in a high temperature and high humidity environment, ground stains occurred after the deterioration test and the image quality was not stable. This is because zinc oxide is not contained in the undercoat layer (see Comparative Examples 7 to 9), or because the stirring time when preparing the undercoat layer coating liquid is short, zinc oxide is contained in the undercoat layer. It can be said that this is due to the fact that they are not sufficiently dispersed (see Comparative Examples 10 and 11).

Therefore, in the electrophotographic photosensitive member according to the present embodiment, even in a high temperature and high humidity environment, more stable image quality, particularly an image in which color spot-like stains are improved, and further, color spot-like stains are obtained for a long period of time. It can be said that an image in which both the ground stain and the ground stain are improved can be obtained.

10A-10D Electrophotographic photosensitive member 11 Support 12 Undercoat layer 13A Single layer type photosensitive layer 13B Laminated type photosensitive layer 20 Image forming apparatus 21, 41 Charged part 22, 42 Exposure part 23, 43 Development part 24, 44 Transfer part 40 Process cartridge

Japanese Unexamined Patent Publication No. 2016-109844

Claims (5)

With the support
Photosensitive layer and
It has an undercoat layer containing zinc oxide and a binder resin,
The support is made of aluminum consisting of Si: 0.10 to 0.25% by mass, Fe: 0.10 to 0.40% by mass, Mn: 0.02 to 0.05% by mass, unavoidable impurities, and the balance Al. Contains alloys
The undercoat layer contains a salicylic acid derivative and contains.
An electrophotographic photosensitive member having a specular reflectance of the undercoat layer of 85% or more. The electrophotographic photosensitive member according to claim 1, wherein the undercoat layer has a thickness of 10 to 20 μm. The electrophotographic photosensitive member according to claim 1 or 2 , wherein the support is formed in a cylindrical shape. The electrophotographic photosensitive member according to any one of claims 1 to 3 and
A charged portion that charges the surface of the electrophotographic photosensitive member and
An exposed portion that exposes the surface of the electrophotographic photosensitive member charged by the charged portion to form an electrostatic latent image, and an exposed portion.
A developing unit that develops the electrostatic latent image into a visible image with toner,
A transfer unit that transfers the visible image to a recording medium,
An image forming apparatus characterized by having. The electrophotographic photosensitive member according to any one of claims 1 to 3 and
A charged portion that charges the surface of the electrophotographic photosensitive member, an exposed portion that exposes the surface of the electrophotographic photosensitive member charged by the charged portion to form an electrostatic latent image, and the electrostatic latent image can be subjected to toner. At least one selected from a developing unit that develops a visual image or a transfer unit that transfers the visible image to a recording medium.
A process cartridge characterized by having.

Images