JP2021110804A - Electrophotographic photoreceptor and image forming apparatus - Google Patents

Abstract

To provide an electrophotographic photoreceptor that has high wear resistance.SOLUTION: An electrophotographic photoreceptor has a conductive substrate, and a single layer-type photosensitive layer that is provided on the conductive substrate, the photosensitive layer including a polycarbonate resin, a charge generating material, a hole transport material having a triarylamine structure, and an electron transport material. When the peak intensity (P2F) of a fingerprint region (695 cm-1) unique to the hole transport material to the peak intensity (1775 cm-1)(P1F) derived from a carbonyl group of the polycarbonate resin in a surface of the photosensitive layer is (PF), and the peak intensity (P2B) of a fingerprint region (695 cm-1) unique to the hole transport material to the peak intensity (1775 cm-1)(P1B) derived from a carbonyl group of the polycarbonate resin on a surface of the photosensitive layer facing the conductive substrate is (PB), which are measured by an infrared spectrophotometer (IR), the (PF) and (PB) satisfy the relationship of 0.2≤(PF)/(PB)≤0.37.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electrophotographic photosensitive member and an image forming apparatus.

Patent Document 1 states that "a single-layer photosensitive layer made of a binder resin containing at least a charge generating agent and a charge transporting agent is provided on a conductive substrate, and the binder resin is a copolymerized polycarbonate resin (A). When two types of the copolymerized polycarbonate resin (B) are contained and the mixing ratio of the copolymerized polycarbonate resin (A) and the copolymerized polycarbonate resin (B) is x: y, 0.1 <bx / 10, A single-layer electrophotographic photosensitive member having 000 <0.5 and x + y = 100. ”Has been proposed.

Further, Patent Document 2 describes that "a positively charged single-layer electrophotographic photosensitive member, a charging device having a contact charging member for charging the surface of the photosensitive member, and the surface of the charged image carrier are exposed. Then, an exposure device for forming an electrostatic latent image on the surface of the image carrier, a developing device for developing the electrostatic latent image as a toner image, and a toner image covered from the image carrier. An image forming apparatus including a transfer device for transferring to a transfer body, wherein the contact charging member is a charging roller made of conductive rubber having a rubber hardness of 62 to 81 ° in Asker-C hardness. An image forming apparatus in which the roller surface roughness of the charging roller of the contact charging member is 55 to 130 μm in an average interval (Sm) of cross-sectional curve irregularities and 9 to 19 μm in a ten-point average roughness (Rz). Is proposed.

Further, Patent Document 3 states, "A photosensitive layer having a single-layer structure including a charge generating material, a charge transporting material, a filler, and a binder resin is formed on a conductive substrate, and includes a charge portion of a contact charging method. A positively charged single-layer electrophotographic photosensitive member used as an image carrier in an image forming apparatus, wherein the filler contains one or more fine particles selected from the group consisting of silica fine particles and resin fine particles, and the filler. A positively charged single-layer electrophotographic photosensitive member having a volume average particle diameter of 5 nm or more and 5 μm or less. ”

Japanese Unexamined Patent Publication No. 2003-255569 Japanese Unexamined Patent Publication No. 2012-14141 Japanese Unexamined Patent Publication No. 2014-130236

An object of the present invention is a conductive substrate, a single-layer type photosensitive layer provided on the conductive substrate, a polycarbonate resin, a charge generating material, a hole transporting material having a triarylamine structure, and electron transporting. ^{In an electrophotographic photosensitive member having a photosensitive layer containing a material, a peak intensity (1775 cm -1} ) (1775 cm -1) derived from the carbonyl group of the polycarbonate resin on the surface of the photosensitive layer as measured by an infrared spectrophotometer (IR). ^{The peak intensity (P2F) of the fingerprint region (695 cm -1} ) peculiar to the hole transport material with respect to P1F) is (PF), and the peak intensity derived from the carbonyl group of the polycarbonate resin on the surface of the photosensitive layer on the conductive substrate side. ^{When the peak intensity (P2B) of the fingerprint region (695 cm -1} ) peculiar to the hole transport material with respect to (1775 cm ^-1 ) (P1B) is (PB), the (PF) and (PB) are 0.2>. Satisfy the relationship of (PF) / (PB) or (PF) / (PB)> 0.37 or 0.18> (PB)-(PF) or (PB)-(PF)> 0.47 It is an object of the present invention to provide an electrophotographic photoconductor having higher wear resistance as compared with an electrophotographic photoconductor.

The above problem is solved by the following means. That is, <1>
A photosensitive layer containing a conductive substrate, a single-layer type photosensitive layer provided on the conductive substrate, a polycarbonate resin, a charge generating material, a hole transporting material having a triarylamine structure, and an electron transporting material. And, which is peculiar to the hole transport material with respect to ^{the peak intensity (1775 cm -1} ) (P1F) derived from the carbonyl group of the polycarbonate resin on the surface of the photosensitive layer, which is measured by an infrared spectrophotometer (IR). The peak intensity (P2F) of the fingerprint region (695 cm ^{-1 ) is set to (PF), and the peak intensity (1775 cm -1} ) (P1B) derived from the carbonyl group of the polycarbonate resin on the surface of the photosensitive layer on the conductive substrate side is described. When the peak intensity (P2B) of the fingerprint region (695 cm ^-1 ) peculiar to the hole transport material is (PB), the above (PF) and (PB) are 0.2 ≦ (PF) / (PB) ≦ 0. An electrophotographic photosensitive member that satisfies the relationship of 37.
<2>
The electrophotographic photosensitive member according to <1>, wherein the hole transport material is a compound represented by the general formula (a-2).
<3>
The electrophotographic photosensitive member according to <2>, wherein the hole transport material is a compound represented by the following formula HT-1.
<4>
The electrophotographic photosensitive member according to any one of <1> to <3>, wherein the content of the hole transporting material is 10% by mass or more and 50% by mass or less with respect to the total solid content of the photosensitive layer. ..
<5>
The electrophotographic photosensitive member according to <4>, wherein the content of the hole transporting material is 38% by mass or more and 48% by mass or less with respect to the total solid content of the photosensitive layer.
<6>
A photosensitive layer containing a conductive substrate, a single-layer type photosensitive layer provided on the conductive substrate, a polycarbonate resin, a charge generating material, a hole transporting material having a triarylamine structure, and an electron transporting material. And, which is peculiar to the hole transport material with respect to ^{the peak intensity (1775 cm -1} ) (P1F) derived from the carbonyl group of the polycarbonate resin on the surface of the photosensitive layer, which is measured by an infrared spectrophotometer (IR). The peak intensity (P2F) of the fingerprint region (695 cm ^{-1 ) is set to (PF), and the peak intensity (1775 cm -1} ) (P1B) derived from the carbonyl group of the polycarbonate resin on the surface of the photosensitive layer on the conductive substrate side is described. When the peak intensity (P2B) of the fingerprint region (695 cm ^-1 ) peculiar to the hole transport material is (PB), the above (PF) and (PB) are 0.18 ≦ (PB) − (PF) ≦ 0. An electrophotographic photoconductor that satisfies the relationship of .47.
<7>
The electrophotographic photosensitive member according to any one of <1> to <6>, a charging means for charging the surface of the electrophotographic photosensitive member, and an electrostatic latent image on the surface of the charged electrophotographic photosensitive member. The electrostatic latent image forming means to be formed, the developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image, and the toner image are recorded. An image forming apparatus including a transfer means for transferring to the surface of a medium.
<8>
The charging means is a charging means having a scorotron charger, the developing means is a developing means that uses a non-magnetic one-component developer to clean the electrophotographic photosensitive member at the same time as development, and the transfer means is the toner. The image forming apparatus according to <7>, which is a direct transfer type transfer means for directly transferring an image to the surface of the recording medium.

According to the invention according to <1>, a conductive substrate, a single-layer type photosensitive layer provided on the conductive substrate, and a hole transport having a polycarbonate resin, a charge generating material, and a triarylamine structure. In an electrophotographic photosensitive member having a photosensitive layer containing a material and an electron transporting material, a peak intensity (1775 cm) derived from the carbonyl group of the polycarbonate resin on the surface of the photosensitive layer as measured by an infrared spectrophotometer (IR). ^{-1 ) The peak intensity (P2F) of the fingerprint region (695 cm -1} ) peculiar to the hole transport material with respect to (P1F) is set to (PF), and the carbonyl group of the polycarbonate resin on the surface of the photosensitive layer on the conductive substrate side. When the peak intensity (P2B) of the hole transport material-specific fingerprint region (695 cm ^{-1 ) with respect to the derived peak intensity (1775 cm -1} ) (P1B) is (PB), the (PF) and (PB) are Provided is an electrophotographic photosensitive member having higher wear resistance as compared with an electrophotographic photosensitive member satisfying the relationship of 0.2> (PF) / (PB) or (PF) / (PB)> 0.37. ..

According to the inventions <2> and <3>, an electrophotographic photosensitive member having higher wear resistance than the electrophotographic photosensitive member whose hole transport material is HT-4 or HT-11 is provided. Will be done.

According to the inventions of <4> and <5>, the electrophotographic photosensitive member whose content of the hole transporting material is less than 10% by mass or more than 50% by mass with respect to the total solid content of the photosensitive layer. In comparison, an electrophotographic photosensitive member having high wear resistance is provided.

According to the invention according to <6>, a conductive substrate, a single-layer type photosensitive layer provided on the conductive substrate, and a hole transport having a polycarbonate resin, a charge generating material, and a triarylamine structure. In an electrophotographic photosensitive member having a photosensitive layer containing a material and an electron transporting material, a peak intensity (1775 cm) derived from the carbonyl group of the polycarbonate resin on the surface of the photosensitive layer as measured by an infrared spectrophotometer (IR). ^{-1 ) The peak intensity (P2F) of the fingerprint region (695 cm -1} ) peculiar to the hole transport material with respect to (P1F) is set to (PF), and the carbonyl group of the polycarbonate resin on the surface of the photosensitive layer on the conductive substrate side. When the peak intensity (P2B) of the hole transport material-specific fingerprint region (695 cm ^{-1 ) with respect to the derived peak intensity (1775 cm -1} ) (P1B) is (PB), the (PF) and (PB) are Provided is an electrophotographic photosensitive member having higher wear resistance as compared with an electrophotographic photosensitive member satisfying the relationship of 0.18> (PF)-(PB) or (PF)-(PB)> 0.47. ..

According to the inventions <7> and <8>, a conductive substrate and a single-layer type photosensitive layer provided on the conductive substrate, which comprises a polycarbonate resin, a charge generating material, and a triarylamine structure. Derived from the carbonyl group of the polycarbonate resin on the surface of the photosensitive layer as measured by an infrared spectrophotometer (IR) in an electrophotographic photosensitive member having a photosensitive layer containing a hole transporting material and an electron transporting material. the hole peak intensity of transport material unique fingerprint area (695cm ^-1) a (P2F) (PF), the surface of the conductive base side of the photosensitive layer, wherein the polycarbonate to the peak intensity (1775cm ^-1) (P1F) ^{When the peak intensity (P2B) of the fingerprint region (695 cm -1} ) peculiar to the hole transport material with respect to ^{the peak intensity (1775 cm -1} ) (P1B) derived from the carbonyl group of the resin is (PB), the above (PF) and (PB) is 0.2> (PF) / (PB) or (PF) / (PB)> 0.37 or 0.18> (PB)-(PF) or (PB)-(PF)> An image forming apparatus including an electrophotographic photosensitive member having high wear resistance is provided as compared with the case where the electrophotographic photosensitive member satisfies the relationship of 0.47.

It is a schematic partial cross-sectional view which shows an example of the layer structure of the electrophotographic photosensitive member which concerns on this embodiment. It is a schematic block diagram which shows an example of the image forming apparatus which concerns on this embodiment. It is a schematic block diagram which shows another example of the image forming apparatus which concerns on this embodiment.

Hereinafter, embodiments that are an example of the present invention will be described. These descriptions and examples illustrate embodiments and do not limit the scope of the invention.
In the numerical range described stepwise in the present specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described stepwise. good. Further, in the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

Each component may contain a plurality of applicable substances.
When referring to the amount of each component in the composition, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, the sum of the multiple substances present in the composition. Means quantity.

[Electrophotophotoreceptor]
The electrophotographic photosensitive member (hereinafter, also referred to as “photoreceptor”) according to the present embodiment is
With a conductive substrate
A single-layer type photosensitive layer (hereinafter, also referred to as “photosensitive layer”) provided on the conductive substrate, which comprises a polycarbonate resin, a charge generating material, a hole transporting material having a triarylamine structure, and an electron transporting material. With a photosensitive layer, including
The hole transport material-specific fingerprint region (695 cm ^{-1 ) with respect to the peak intensity (1775 cm -1} ) (P1F) derived from the carbonyl group of the polycarbonate resin on the surface of the photosensitive layer as measured by an infrared spectrophotometer (IR). ) Is the peak intensity (P2F) of (PF), which is unique to the hole transport material with respect to ^{the peak intensity (1775 cm -1} ) (P1B) derived from the carbonyl group of the polycarbonate resin on the surface of the photosensitive layer on the conductive substrate side. When the peak intensity (P2B) of the fingerprint area (695 cm ^-1 ) is (PB), the relationship between (PF) and (PB) is 0.2 ≦ (PF) / (PB) ≦ 0.37 or 0. An electrophotographic photosensitive member satisfying the relationship of 18 ≦ (PB) − (PF) ≦ 0.47.

In the photoconductor according to the present embodiment, the abrasion resistance of the photosensitive layer is improved by the above configuration. The reason is presumed as follows.

Since the hole transport material contained in the photosensitive layer of the photoconductor is a small molecule, it has a function of a plasticizer. Therefore, if a large amount of hole transporting material is present on the surface of the photosensitive layer, the mechanical strength of the surface of the photosensitive layer is excessively lowered. Therefore, when the image is repeatedly formed, the surface may be excessively scraped by a mechanical load of a charging device, a cleaning device, or the like in contact with the photoconductor.

In the photoconductor according to the present embodiment, the above (PF) and (PB) have a relationship of 0.2 ≦ (PF) / (PB) ≦ 0.37 or 0.18 ≦ (PB) − (PF) ≦ 0. Satisfy 47 relationships. That is, the number of hole transporting materials contained in the surface of the photosensitive layer of the photoconductor is smaller than that of the hole transporting material contained in the surface of the photosensitive layer on the conductive substrate side. Therefore, it is possible to suppress an excessive decrease in the mechanical strength of the surface of the photoconductor, and the surface is less likely to be scraped even by repeatedly forming an image.

Therefore, the wear-resistant material of the photoconductor according to the present embodiment is improved.

The portion where the hole transport material is present on the surface of the photosensitive layer may be locally scraped by a mechanical load. The resistance (bulk resistance) of the photosensitive layer decreases in the locally scraped portion of the surface of the photosensitive layer. Along with this, when the photosensitive layer is charged, it is locally discharged, which may cause charge leakage. Then, color spots may be generated by the toner adhering to the point where the electric charge leaks (leak point).

Therefore, in the photoconductor according to the present embodiment, the decrease in bulk resistance and the occurrence of leaks are suppressed, and image defects such as color spots are also suppressed.

Hereinafter, the electrophotographic photosensitive member according to the present embodiment will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts will be designated by the same reference numerals, and duplicate description will be omitted.

FIG. 1 schematically shows a cross section of a part of the electrophotographic photosensitive member 7 according to the present embodiment. In the electrophotographic photosensitive member 7 shown in FIG. 1, for example, the conductive substrate 3 and the undercoat layer 1 and the single-layer type photosensitive layer 2 are provided on the conductive substrate 3 in this order.
The undercoat layer 1 is a layer provided as needed. That is, the single-layer type photosensitive layer 2 may be provided directly on the conductive substrate 3, or may be provided via the undercoat layer 1.

The electrophotographic photosensitive member shown in FIG. 1 may be further provided with other layers, if necessary. Examples of other layers include an intermediate layer provided between the undercoat layer and the photosensitive layer.

Hereinafter, each layer of the electrophotographic photosensitive member according to the present embodiment will be described in detail. The reference numerals will be omitted.

(Conductive substrate)
Examples of the conductive substrate include metal plates containing metals (aluminum, copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold, platinum, etc.) or alloys (stainless steel, etc.), metal drums, metal belts, and the like. Can be mentioned. Examples of the conductive substrate include paper, resin film, belt and the like coated, vapor-deposited or laminated with a conductive compound (for example, conductive polymer, indium oxide, etc.), metal (for example, aluminum, palladium, gold, etc.) or alloy. Can also be mentioned. Here, "conductive" means that the volume resistivity is less than ^{10 13 Ωcm.}

When the electrophotographic photosensitive member is used in a laser printer, the surface of the conductive substrate has a centerline average roughness Ra of 0.04 μm or more and 0.5 μm for the purpose of suppressing interference fringes generated when irradiating the laser beam. It is preferable that the surface is roughened below. When non-interfering light is used as the light source, roughening to prevent interference fringes is not particularly necessary, but it is suitable for longer life because it suppresses the occurrence of defects due to the unevenness of the surface of the conductive substrate.

Roughening methods include, for example, wet honing performed by suspending an abrasive in water and spraying it onto a conductive substrate, and centerless grinding in which a conductive substrate is pressed against a rotating grindstone and continuously ground. , Anodizing treatment and the like.

As a method of roughening, the conductive or semi-conductive powder is dispersed in the resin without roughening the surface of the conductive substrate to form a layer on the surface of the conductive substrate. Another method is to roughen the surface with particles dispersed in the layer.

In the roughening treatment by anodizing, an oxide film is formed on the surface of the conductive substrate by anodizing in an electrolyte solution using a conductive substrate made of metal (for example, made of aluminum) as an anode. Examples of the electrolyte solution include sulfuric acid solution, oxalic acid solution and the like. However, the porous anodized film formed by anodizing is chemically active as it is, is easily contaminated, and has a large resistance fluctuation depending on the environment. Therefore, for the porous anodic oxide film, the micropores of the oxide film are closed by volume expansion due to the hydration reaction in pressurized steam or boiling water (a metal salt such as nickel may be added), and more stable hydration oxidation is performed. It is preferable to perform a hole-sealing treatment to change the material.

The film thickness of the anodic oxide film is preferably, for example, 0.3 μm or more and 15 μm or less. When this film thickness is within the above range, the barrier property against injection tends to be exhibited, and the increase in the residual potential due to repeated use tends to be suppressed.

The conductive substrate may be treated with an acidic treatment liquid or a boehmite treatment.
The treatment with the acidic treatment liquid is carried out as follows, for example. First, an acidic treatment solution containing phosphoric acid, chromic acid and hydrofluoric acid is prepared. The blending ratio of phosphoric acid, chromic acid and hydrofluoric acid in the acidic treatment liquid is, for example, phosphoric acid in the range of 10% by mass or more and 11% by mass or less, chromic acid in the range of 3% by mass or more and 5% by mass or less, and phosphoric acid. It is preferably in the range of 0.5% by mass or more and 2% by mass or less, and the concentration of these acids as a whole is preferably in the range of 13.5% by mass or more and 18% by mass or less. The treatment temperature is preferably, for example, 42 ° C. or higher and 48 ° C. or lower. The film thickness of the coating is preferably 0.3 μm or more and 15 μm or less.

The boehmite treatment is carried out, for example, by immersing in pure water at 90 ° C. or higher and 100 ° C. or lower for 5 to 60 minutes, or by contacting with heated steam at 90 ° C. or higher and 120 ° C. or lower for 5 to 60 minutes. The film thickness of the coating is preferably 0.1 μm or more and 5 μm or less. This can be further anodized with an electrolyte solution having low film solubility such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, citrate, etc. good.

(Underlay layer)
The undercoat layer is, for example, a layer containing inorganic particles and a binder resin.

Examples of the inorganic particles include inorganic particles having a powder resistivity (volume resistivity) of 10 ² Ωcm or more and 10 ¹¹ Ωcm or less.
Among these, as the inorganic particles having the above resistance value, for example, metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, and zirconium oxide particles are preferable, and zinc oxide particles are particularly preferable.

The specific surface area of the inorganic particles by the BET method is, for example, ^{preferably 10 m 2} / g or more.
The volume average particle diameter of the inorganic particles is, for example, preferably 50 nm or more and 2000 nm or less (preferably 60 nm or more and 1000 nm or less).

The content of the inorganic particles is, for example, preferably 10% by mass or more and 80% by mass or less, and more preferably 40% by mass or more and 80% by mass or less with respect to the binder resin.

The inorganic particles may be surface-treated. As the inorganic particles, those having different surface treatments or those having different particle diameters may be mixed and used.

Examples of the surface treatment agent include a silane coupling agent, a titanate-based coupling agent, an aluminum-based coupling agent, a surfactant and the like. In particular, a silane coupling agent is preferable, and a silane coupling agent having an amino group is more preferable.

Examples of the silane coupling agent having an amino group include 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, and N-2- (aminoethyl) -3-amino. Examples thereof include, but are not limited to, propylmethyldimethoxysilane and N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane.

Two or more kinds of silane coupling agents may be mixed and used. For example, a silane coupling agent having an amino group may be used in combination with another silane coupling agent. Other silane coupling agents include, for example, vinyltrimethoxysilane, 3-methacryloxypropyl-tris (2-methoxyethoxy) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glyceride. Sidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- ( Aminoethyl) -3-aminopropylmethyldimethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, 3-chloropropyltrimethoxysilane and the like can be mentioned, but are limited thereto. It's not a thing.

The surface treatment method using a surface treatment agent may be any known method, and may be either a dry method or a wet method.

The treatment amount of the surface treatment agent is, for example, preferably 0.5% by mass or more and 10% by mass or less with respect to the inorganic particles.

Here, it is preferable that the undercoat layer contains an electron acceptor compound (acceptor compound) together with the inorganic particles from the viewpoint of enhancing the long-term stability of the electrical characteristics and the carrier blocking property.

Examples of the electron-accepting compound include quinone compounds such as chloranyl and bromoanyl; tetracyanoquinodimethane compounds; 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitro-9-fluorenone and the like. Fluolenone compounds; 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (4-naphthyl) -1,3,4- Oxadiazole compounds such as oxadiazole, 2,5-bis (4-diethylaminophenyl) -1,3,4 oxadiazole; xanthone compounds; thiophene compounds; 3,3', 5,5'tetra- Examples thereof include electron-transporting substances such as diphenoquinone compounds such as t-butyldiphenoquinone;
In particular, as the electron-accepting compound, a compound having an anthraquinone structure is preferable. As the compound having an anthraquinone structure, for example, a hydroxyanthraquinone compound, an aminoanthraquinone compound, an aminohydroxyanthraquinone compound and the like are preferable, and specifically, for example, anthraquinone, alizarin, quinizarin, anthralfin, purpurin and the like are preferable.

The electron-accepting compound may be dispersed and contained in the undercoat layer together with the inorganic particles, or may be contained in a state of being attached to the surface of the inorganic particles.

Examples of the method for adhering the electron-accepting compound to the surface of the inorganic particles include a dry method and a wet method.

In the dry method, for example, while stirring inorganic particles with a mixer having a large shearing force, an electron-accepting compound dissolved directly or in an organic solvent is dropped and sprayed together with dry air or nitrogen gas to obtain an electron-accepting compound. This is a method of adhering to the surface of inorganic particles. When dropping or spraying the electron-accepting compound, it is preferable to carry out at a temperature equal to or lower than the boiling point of the solvent. After dropping or spraying the electron-accepting compound, baking may be further performed at 100 ° C. or higher. The printing is not particularly limited as long as the temperature and time at which the electrophotographic characteristics can be obtained.

In the wet method, for example, an electron-accepting compound is added while dispersing inorganic particles in a solvent by stirring, ultrasonic waves, a sand mill, an attritor, a ball mill, or the like, and after stirring or dispersing, the solvent is removed to remove electrons. This is a method of adhering an accepting compound to the surface of inorganic particles. The solvent removing method is distilled off, for example, by filtration or distillation. After removing the solvent, baking may be further performed at 100 ° C. or higher. The printing is not particularly limited as long as the temperature and time at which the electrophotographic characteristics can be obtained. In the wet method, the water content of the inorganic particles may be removed before the electron-accepting compound is added. Examples thereof include a method of removing by stirring and heating in a solvent, and a method of removing by azeotropically boiling with a solvent. Can be mentioned.

The electron-accepting compound may be attached before or after the surface treatment with the surface treatment agent is applied to the inorganic particles, and the electron-accepting compound may be attached and the surface treatment with the surface treatment agent may be performed at the same time.

The content of the electron-accepting compound is, for example, preferably 0.01% by mass or more and 20% by mass or less, preferably 0.01% by mass or more and 10% by mass or less, based on the inorganic particles.

Examples of the binder resin used for the undercoat layer include acetal resin (for example, polyvinyl butyral), polyvinyl alcohol resin, polyvinyl acetal resin, casein resin, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, and unsaturated polyester. Resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, urea resin, phenol resin, phenol-formaldehyde resin, melamine resin, Known polymer compounds such as urethane resin, alkyd resin, and epoxy resin; zirconium chelate compound; titanium chelate compound; aluminum chelate compound; titanium alkoxide compound; organic titanium compound; known materials such as silane coupling agent can be mentioned.
Examples of the binder resin used for the undercoat layer include a charge-transporting resin having a charge-transporting group, a conductive resin (for example, polyaniline, etc.) and the like.

Among these, as the binder resin used for the undercoat layer, a resin insoluble in the coating solvent of the upper layer is preferable, and in particular, a urea resin, a phenol resin, a phenol-formaldehyde resin, a melamine resin, a urethane resin, and an unsaturated polyester. Thermocurable resins such as resins, alkyd resins, epoxy resins; with at least one resin selected from the group consisting of polyamide resins, polyester resins, polyether resins, methacrylic resins, acrylic resins, polyvinyl alcohol resins and polyvinyl acetal resins. A resin obtained by reacting with a curing agent is preferable.
When two or more of these binder resins are used in combination, the mixing ratio thereof is set as necessary.

The undercoat layer may contain various additives for improving electrical characteristics, environmental stability, and image quality.
Examples of the additive include known materials such as electron-transporting pigments such as polycyclic condensation type and azo type, zirconium chelate compound, titanium chelate compound, aluminum chelate compound, titanium alkoxide compound, organic titanium compound, and silane coupling agent. Be done. The silane coupling agent is used for surface treatment of inorganic particles as described above, but may be further added to the undercoat layer as an additive.

Examples of the silane coupling agent as an additive include vinyltrimethoxysilane, 3-methacryloxypropyl-tris (2-methoxyethoxy) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and 3-. Glycydoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (Aminoethyl) -3-aminopropylmethyldimethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, 3-chloropropyltrimethoxysilane and the like can be mentioned.

Examples of the zirconium chelate compound include zirconium butoxide, zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, zirconium acetate zirconium butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octanoate. Examples thereof include zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, zirconium methacrylate butoxide, stearate zirconium butoxide, and isosterate zirconium butoxide.

Examples of the titanium chelate compound include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, and titanium lactate ammonium salt. , Titanium Lactate, Titanium Lactate Ethyl Ester, Titanium Triethanol Aminate, Polyhydroxy Titanium Steerate and the like.

Examples of the aluminum chelate compound include aluminum isopropylate, monobutoxyaluminum diisopropyrate, aluminum butyrate, diethylacetacetate aluminum diisopropirate, aluminum tris (ethylacetacetate) and the like.

These additives may be used alone or as a mixture or polycondensate of multiple compounds.

The undercoat layer preferably has a Vickers hardness of 35 or more.
The surface roughness (ten-point average roughness) of the undercoat layer ranges from 1 / (4n) (n is the refractive index of the upper layer) to 1/2 of the exposure laser wavelength λ used for suppressing moire images. It should be adjusted to.
Resin particles or the like may be added to the undercoat layer to adjust the surface roughness. Examples of the resin particles include silicone resin particles and crosslinked polymethyl methacrylate resin particles. Further, the surface of the undercoat layer may be polished to adjust the surface roughness. Examples of the polishing method include buffing, sandblasting, wet honing, and grinding.

The formation of the undercoat layer is not particularly limited, and a well-known forming method is used. For example, a coating film of a coating liquid for forming an undercoat layer in which the above components are added to a solvent is formed, and the coating film is dried. Then, if necessary, heat it.

As the solvent for preparing the coating liquid for forming the undercoat layer, known organic solvents such as alcohol-based solvent, aromatic hydrocarbon solvent, halogenated hydrocarbon solvent, ketone-based solvent, ketone alcohol-based solvent, and ether-based solvent are used. Examples thereof include solvents and ester-based solvents.
Specific examples of these solvents include methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellsolve, ethyl cell solution, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, and the like. Examples thereof include ordinary organic solvents such as n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene and toluene.

Examples of the method for dispersing the inorganic particles when preparing the coating liquid for forming the undercoat layer include known methods such as a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker.

Examples of the method of applying the coating liquid for forming the undercoat layer onto the conductive substrate include a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method. Ordinary methods such as.

The film thickness of the undercoat layer is set, for example, preferably in the range of 15 μm or more, more preferably 20 μm or more and 50 μm or less.

(Middle layer)
Although not shown, an intermediate layer may be further provided between the undercoat layer and the photosensitive layer.
The intermediate layer is, for example, a layer containing a resin. Examples of the resin used for the intermediate layer include acetal resin (for example, polyvinyl butyral), polyvinyl alcohol resin, polyvinyl acetal resin, casein resin, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, and acrylic resin. Examples thereof include polymer compounds such as polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, and melamine resin.
The intermediate layer may be a layer containing an organometallic compound. Examples of the organometallic compound used for the intermediate layer include organometallic compounds containing metal atoms such as zirconium, titanium, aluminum, manganese, and silicon.
The compounds used for these intermediate layers may be used alone or as a mixture or polycondensate of a plurality of compounds.

Among these, the intermediate layer is preferably a layer containing an organometallic compound containing a zirconium atom or a silicon atom.

The formation of the intermediate layer is not particularly limited, and a well-known forming method is used. For example, a coating film of an intermediate layer forming coating solution in which the above components are added to a solvent is formed, and the coating film is dried and required. It is performed by heating according to the above.
As a coating method for forming the intermediate layer, ordinary methods such as a dip coating method, a push-up coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, and a curtain coating method are used.

The film thickness of the intermediate layer is preferably set in the range of 0.1 μm or more and 3 μm or less. The intermediate layer may be used as the undercoat layer.

(Single layer type photosensitive layer)
The single-layer photosensitive layer includes a polycarbonate resin, a charge generating material, a hole transporting material having a triarylamine structure, and an electron transporting material.

-Polycarbonate resin-
Polycarbonate resin is applied as the binder resin.
It is preferable that the polycarbonate resin has a structural unit represented by the following general formula (PC) from the viewpoint of improving the abrasion resistance of the photoconductor and suppressing the color point.

In the general formula (PC), ^RP1 and ^RP2 independently represent a hydrogen atom, a substituted or unsubstituted alkyl group having 5 or less carbon atoms, or a substituted or unsubstituted phenyl group, respectively, and ^RP1 and ^RP2. A cyclo ring may be formed with and.
^RP3 and ^RP4 each independently represent a hydrogen atom or a substituted or unsubstituted alkyl group having 3 or less carbon atoms.

In the general formula (PC), ^{examples of the alkyl group having 5 or less carbon atoms represented by RP1} and ^RP2 are linear or branched alkyl groups, respectively, and include methyl group, ethyl group, and n-propyl. Examples thereof include a group, an n-butyl group, an n-pentyl group, an isopropyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an isopentyl group, a neopentyl group and a tert-pentyl group.

In the general formula (PC) ^{, examples of the substituent further contained in the alkyl group having 5 or less carbon atoms represented by RP1} and ^RP2 or the phenyl group include a halogen atom (for example, a fluorine atom and a chlorine atom) and an alkyl group (for example, carbon). Alkyl group of number 1 or more and 6 or less), cycloalkyl group (for example, cycloalkyl group of 5 or more and 7 or less carbon number), alkoxy group (for example, alkoxy group of 1 or more and 4 or less carbon number), aryl group (for example, phenyl group, A naphthyl group, a biphenylyl group, etc.) and the like can be mentioned.

In formula ^(PC), cyclo ring (i.e. that formed by the ^{R P1} and ^{R P2,} a group represented by ^{R P,} a ^{group R P2} represents ^a carbon atom ^{R P1} and ^{R P2} are bonded directly, in configuration Examples of the cycloring ring) include substituted or unsubstituted cycloalkylene groups. Examples of the substituent further possessed by the cycloalkylene group include the same substituents further possessed by the alkyl group having 5 or less carbon atoms represented by ^RP1 and ^{RP2 in the general formula (PC) or the phenyl group.}
The number of carbon atoms of the cycloalkylene group (however, in the case of a substituted cycloalkylene group, the number of carbon atoms of the substituent having more carbon atoms is excluded) is preferably 3 or more and 12 or less, more preferably 3 or more and 10 or less, and further preferably 5 or more and 8 or less. .. Specific examples of the cycloalkylene group include a cyclopropylene group, a cyclopentylene group, a cyclohexylene group, a cyclooctylene group, a cyclododecanylen group and the like. Among these, the cyclohexylene group is preferable as the cycloalkylene group.

^{R P1} and ^{R P2} in formula (PC) are each independently a hydrogen atom, an unsubstituted alkyl group having 5 or less carbon atoms, unsubstituted phenyl ^group, an unsubstituted formed by the ^{R P1} and ^{R P2} cycloalkylene group are preferable, an unsubstituted methyl group, an unsubstituted phenyl group, an unsubstituted cyclohexylene group is more preferably formed by the R ^P1 and R ^2P, non formed by the R ^P1 and R ^P2 Substituted cyclohexylene groups are more preferred.

In the general formula (PC), the alkyl group having 3 or less carbon atoms represented by ^RP3 and ^RP4 has 3 or less carbon atoms among the alkyl groups having 5 or less carbon atoms represented by ^RP1 and ^{RP2 in the general formula (PC).} The same thing as the one can be mentioned.
Further, in the general formula (PC), the substituent further contained in the alkyl group having 3 or less carbon atoms represented by ^RP3 and ^RP4 is an alkyl having 5 or less carbon atoms represented by ^RP1 and ^{RP2 in the general formula (PC).} Examples include the same substituents further possessed by the group or phenyl group.

In the general formula (PC), ^RP3 and ^RP4 are independently preferable to have a hydrogen atom and an unsubstituted alkyl group having 3 or less carbon atoms, more preferably a hydrogen atom and an unsubstituted methyl group, respectively, and ^RP1 and R. A cyclohexylene group formed with ^{P2 is more preferable.}

Specific examples of the structural unit represented by the general formula (PC) include a structural unit represented by the following structural formula.

The polycarbonate resin may be a resin having a structural unit represented by one general formula (PC) (that is, a copolymer), or a structural unit represented by two or more general formulas (PC). It may be a resin (that is, a copolymer) having.

The viscosity average molecular weight of the polycarbonate resin is preferably 20,000 or more and 50,000 or less, more preferably 20,000 or more and 45,000 or less, and 20,000 or more and 40,000 or less, from the viewpoint of improving the abrasion resistance of the photoconductor and suppressing the color point. It is more preferable to have.

Here, the following one-point measurement method is used for measuring the viscosity average molecular weight of the polycarbonate resin.
First, the photosensitive layer to be measured is exposed from the photoconductor. Then, a part of the photosensitive layer is cut out to prepare a sample for measurement.
Next, the polycarbonate resin is extracted from the measurement sample. 1 g of the extracted polycarbonate resin ^{is dissolved in 100 cm 3} of methylene chloride, and its specific viscosity ηsp is measured with an Ubbelohde viscometer in a measurement environment of 25 ° C. Then, the relational expression of ηsp / c = [η] + 0.45 [η] ² c (where c is the concentration (g / cm ³ )) is used to obtain the ultimate viscosity [η] (cm ^{3 / g).} The viscosity average molecular weight Mv is obtained from the given formula, [η] = 1.23 × 10 ^-4 Mv ^0.83.

The content of the polycarbonate resin in the entire photosensitive layer includes, for example, a range of 35% by mass or more and 60% by mass or less, preferably a range of 40% by mass or more and 60% by mass or less, and 50% by mass or more and 60% by mass or less. The range is more preferred.

-Charge generating material-
Examples of the charge generating material include azo pigments such as bisazo and trisazo; condensed ring aromatic pigments such as dibromoanthanthron; perylene pigment; pyrrolopyrrole pigment; phthalocyanine pigment; zinc oxide; trigonal selenium and the like.

Among these, in order to correspond to laser exposure in the near infrared region, it is preferable to use a metal phthalocyanine pigment or a metal-free phthalocyanine pigment as the charge generating material. Specific examples thereof include hydroxygallium phthalocyanine; chlorogallium phthalocyanine; dichloromethane phthalocyanine; titanyl phthalocyanine.

On the other hand, in order to support laser exposure in the near-ultraviolet region, as a charge generating material, a condensed ring aromatic pigment such as dibromoanthanthrone; a thioindigo pigment; a porphyrazine compound; zinc oxide; a trigonal selenium; a bisazo pigment Etc. may be used.

That is, as the charge generating material, for example, when a light source having an exposure wavelength of 380 nm or more and 500 nm or less is used, an inorganic pigment is preferably used, and when a light source having an exposure wavelength of 700 nm or more and 800 nm or less is used, a metal or a metal-free material is used. Phthalocyanine pigments may be used.

Above all, as the charge generating material, it is desirable to use at least one selected from hydroxygallium phthalocyanine pigment and chlorogallium phthalocyanine pigment. As these charge generating materials, they may be used alone or in combination of two or more. From the viewpoint of light sensitivity, hydroxygallium phthalocyanine pigment is preferable.
When the hydroxygallium phthalocyanine pigment and the chlorogallium phthalocyanine pigment are used in combination, the ratio of the hydroxygallium phthalocyanine pigment to the chlorogallium phthalocyanine pigment is a mass ratio. It is preferably 3: 7 (preferably 9: 1 to 6: 4).

The hydroxygallium phthalocyanine pigment is not particularly limited, but a V-type hydroxygallium phthalocyanine pigment is preferable from the viewpoint of light sensitivity.
In particular, as the hydroxygallium phthalocyanine pigment, for example, in the spectral absorption spectrum in the wavelength range of 600 nm or more and 900 nm or less, the hydroxygallium phthalocyanine pigment having the maximum peak wavelength in the range of 810 nm or more and 839 nm or less can obtain more excellent dispersibility. Desirable from the point of view.

Further, the hydroxygallium phthalocyanine pigment having the maximum peak wavelength in the range of 810 nm or more and 839 nm or less preferably has an average particle size in a specific range and a BET specific surface area in a specific range. Specifically, the average particle size is preferably 0.20 μm or less, and more preferably 0.01 μm or more and 0.15 μm or less. On the other hand, the BET specific surface area is ^{preferably 45 m 2} / g or more, more preferably 50 m ² / g or more, and further preferably 55 m ² / g or more and 120 m ² / g or less. The average particle size is a volume average particle size, which is a value measured by a laser diffraction / scattering type particle size distribution measuring device (HORIBA, Ltd. LA-700). The BET specific surface area is a value measured by the nitrogen substitution method using a fluidized specific surface area automatic measuring device (Shimadzu Flow Soap II 2300).

The maximum particle size (maximum value of the primary particle size) of the hydroxygallium phthalocyanine pigment is preferably 1.2 μm or less, more preferably 1.0 μm or less, and further preferably 0.3 μm or less.

The hydroxygallium phthalocyanine pigment preferably has an average particle size of 0.2 μm or less, a maximum particle size of 1.2 μm or less, and a BET specific surface area of 45 m ² / g or more.

The hydroxygallium phthalocyanine pigment has a Bragg angle (2θ ± 0.2 °) of at least 7.3 °, 16.0 °, 24.9 °, and 28.0 ° in the X-ray diffraction spectrum using CuKα characteristic X-ray. It is preferably V-shaped having a diffraction peak.

On the other hand, the chlorogallium phthalocyanine pigment has diffraction peaks at Bragg angles (2θ ± 0.2 °) of 7.4 °, 16.6 °, 25.5 ° and 28.3 ° from the viewpoint of sensitivity of the photosensitive layer. The compound having is preferable. The preferred ranges of maximum peak wavelength, average particle size, maximum particle size, and BET specific surface area of the chlorogallium phthalocyanine pigment are the same as those of the hydroxygallium phthalocyanine pigment.

As the charge generating material, one kind may be used alone, or two or more kinds may be used in combination.

The content of the charge generating material with respect to the total solid content of the single-layer type photosensitive layer is preferably 0.5% by mass or more and 5% by mass or less, preferably 1% by mass or more and 5% by mass or less, and 1.2% by mass or more 4 More preferably, it is 5.5% by mass or less.

-Hole transport material-
The hole transport material according to this embodiment has a triarylamine structure.
Examples of the hole transport material include compounds having one or two triarylamine structures in the same molecule, and from the viewpoint of improving the abrasion resistance of the photoconductor and suppressing color spots, the hole transport material has two triarylamine structures. The compound is preferable, and a benzidine compound having two triarylamine structures is more preferable.

Specific examples of the hole transport material include a compound represented by the following general formula (a-1) and a compound represented by the following general formula (a-2). Among them, the compound represented by the following general formula (a-2) is preferable as the hole transporting material from the viewpoint of improving the abrasion resistance of the photoconductor and suppressing the color spot.

In the structural formulas ^{(a-1), Ar T1} , Ar T2, and ^{Ar T3} each independently represent a substituted or unsubstituted aryl ^{_{group, -C 6 H 4 -C (R}} T4) = C (R T5) (R ^T6 ) or -C ₆ H ₄ -CH = CH-CH = C ( ^RT7 ) ( ^RT8 ) is shown. ^RT4 , ^RT5 , ^RT6 , ^RT7 , and ^RT8 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group.
Examples of the substituent of each of the above groups include a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. Further, examples of the substituent of each of the above groups include a substituted amino group substituted with an alkyl group having 1 or more carbon atoms and 3 or less carbon atoms.

In the structural formula (a-2), ^RT91 and ^RT92 independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. To ^{R T101,} R T102, R ^T111 and ^{R T112} are each independently a halogen atom, 1 to 5 carbon atoms in the alkyl group, 1 to 5 of the alkoxy group carbon atoms, a substituted alkyl group having 1 to 2 carbon atoms The amino group, substituted or unsubstituted aryl group, -C ( ^RT12 ) = C ( ^RT13 ) ( ^RT14 ), or -CH = CH-CH = C ( ^RT15 ) ( ^RT16 ) is shown. ^RT12 , ^RT13 , ^RT14 , ^RT15 and ^RT16 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Tm1, Tm2, Tn1 and Tn2 each independently represent an integer of 0 or more and 2 or less.
Examples of the substituent of each of the above groups include a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. Further, examples of the substituent of each of the above groups include a substituted amino group substituted with an alkyl group having 1 or more carbon atoms and 3 or less carbon atoms.

Here, among the triarylamine derivative represented by the structural formula (a-1) and the benzidine derivative represented by the structural formula (a-2), in particular, "-C ₆ H ₄ -CH = CH-CH =". C ^(R T7) triarylamine derivative having ^{(R T8)} ", and benzidine derivatives having" ^{-CH = CH-CH = C (} R T15) (R T16) ", preferable from the viewpoint of charge mobility.

Hereinafter, specific examples of the compound represented by the general formula (a-1) and the compound represented by the general formula (a-2) include the following structural formulas (HT-1) to (HT-11), which are photoconductors. As the hole transporting material, a compound represented by the following structural formula (HT-1) is preferable from the viewpoint of improving the abrasion resistance and suppressing the color spot.

These hole transporting materials may be used alone or in combination of two or more.

The content of the hole transport material with respect to the total solid content of the photosensitive layer is preferably 10% by mass or more and 50% by mass or less, more preferably 38% by mass or more and 48% by mass or less, and further preferably 38% by mass or more and 44% by mass or less. .. The content of the hole transporting material is the total content of the hole transporting materials when two or more kinds of hole transporting materials are used in combination.

When the content of the hole transporting material with respect to the total solid content of the photosensitive layer is 10% by mass or more, the electrical characteristics are likely to be improved.
When the content of the hole transporting material with respect to the total solid content of the photosensitive layer is 50% by mass or less, the decrease in wear resistance of the photosensitive layer is likely to be suppressed.

-Electron transport material-
The electron transport material is not particularly limited, but for example, quinone compounds such as chloranyl and bromoanyl; tetracyanoquinodimethane compounds; 2,4,7-trinitro-9-fluorenone, 2,4,5,7. Fluolenone compounds such as −tetranitro-9-fluorenone, 9-dicyanomethylene-9-fluorenone-4-carboxylate octyl; 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3 Oxadiazole, oxa such as 2,5-bis (4-naphthyl) -1,3,4-oxadiazole, 2,5-bis (4-diethylaminophenyl) 1,3,4-oxadiazole, etc. Diazole compounds; Xantone compounds; Thiophene compounds; Dinaftquinone compounds such as 3,3'-di-tert-pentyl-dinaftoquinone;3,3'-di-tert-butyl-5,5'-dimethyl Diphenoquinone compounds such as diphenoquinone, 3,3', 5,5'-tetra-tert-butyl-4,4'-diphenoquinone; a polymer having a group composed of the above compounds in the main chain or side chain. ; And so on. These electron transporting materials may be used alone or in combination of two or more.

Among these, the compound represented by the following general formula (C-1) and the compound represented by the following general formula (D-1) are preferable from the viewpoint of improving the sensitivity of the photoconductor.

In the general formula (C-1), ^RC11 , ^RC12 , ^RC13 , and ^RC14 each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, or a phenyl group.

In the general formula ^(C-1), the alkyl group represented by R C11 ^{to R C14,} for example, a linear or branched, include alkyl groups of 1 to 6 carbon atoms, specifically, for example, , Methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group and the like.
Alkyl group represented by R ^C11 to R ^C14 may be a substituted alkyl group. Examples of the substituent of the substituted alkyl group include a cycloalkyl group and a fluorine-substituted alkyl group.

In the general formula ^(C-1), the alkoxy group represented by R C11 ^{to R C14,} for example, include an alkoxy group having 1 to 6 carbon atoms, specifically, methoxy group, an ethoxy group, a propoxy group, Butoxy group and the like can be mentioned.

In the general formula ^(C-1), the halogen atom represented by R C11 ^{to R C14,} for example, a chlorine atom, an iodine atom, a bromine atom and a fluorine atom.

In the general formula ^(C-1), a phenyl group represented by R C11 ^{to R C14} may be a substituted phenyl group. Examples of the substituent of the substituted phenyl group include an alkyl group (for example, an alkyl group having 1 or more and 6 or less carbon atoms), an alkoxy group (for example, an alkoxy group having 1 or more and 6 or less carbon atoms), a biphenyl group and the like.

As the compound represented by the general formula (C-1), one type may be used alone, or two or more types may be used in combination.

Hereinafter, exemplary compounds of the compounds represented by the general formula (C-1) will be shown, but the present invention is not limited thereto.

In the general formula (D-1), R ^D11 , R ^D12 , R ^D13 , R ^D14 , R ^D15 , R ^D16 , and R ^D17 are independently hydrogen atoms, halogen atoms, alkyl groups, alkoxy groups, and aryl groups, respectively. , Or indicates an arylyl group. ^RD18 represents an alkyl group, -L ^D19- O-R ^D20 , an aryl group, or an aralkyl group. However, ^LD19 represents an alkylene group and ^RD20 represents an alkyl group.

In the formula ^(D-1), the halogen atom represented by R D11 ^{to R D17,} for example, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

In the formula ^(D-1), the alkyl group represented by R D11 ^{to R D17,} for example, a linear or branched, include alkyl groups having 1 to 4 carbon atoms (preferably 1 to 3) Specifically, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group and the like can be mentioned.

In the formula ^(D-1), the alkoxy group represented by R D11 ^{to R D17,} for example, include an alkoxy group having 1 to 4 carbon atoms (preferably 1 to 3), specifically, methoxy Groups, ethoxy groups, propoxy groups, butoxy groups and the like can be mentioned.

In the formula ^(D-1), the aryl group represented by R D11 ^{to R D17,} for example, a phenyl group, a tolyl group and the like. Among ^them, the aryl group represented by R D11 ^{to R D17,} is preferably a phenyl group.
In the formula ^(D-1), the aralkyl group represented by R D11 ^{to R D17,} for example, benzyl group, phenethyl group, phenylpropyl group and the like.

In the general formula (D-1) ^{, examples of the alkyl group represented by RD18} include a linear alkyl group having 1 or more and 12 or less carbon atoms (preferably 5 or more and 10 or less carbon atoms) and 3 or more and 10 or less carbon atoms. Examples thereof include branched alkyl groups (preferably having 5 or more and 10 or less carbon atoms).
Examples of the linear alkyl group having 1 to 12 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group and n. Examples thereof include a-octyl group, n-nonyl group, n-decyl, n-undecyl, n-dodecyl group and the like.
Examples of the branched alkyl group having 3 or more and 10 or less carbon atoms include an isopropyl group.
Isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, neopentyl group, tert-pentyl group, isohexyl group, sec-hexyl group, tert-hexyl group, isoheptyl group, sec-heptyl group, tert-heptyl group, Examples thereof include an isooctyl group, a sec-octyl group, a tert-octyl group, an isononyl group, a sec-nonyl group, a tert-nonyl group, an isodecyl group, a sec-decyl group and a tert-decyl group.

In the formula ^(D-1), a group represented by ^-L D19 ^{-O-R D20} indicated by ^{R D18 is L D19} is an alkylene ^{group, R D20} represents an alkyl group.
^Examples of the alkylene group indicated by LD19 include a linear or branched alkylene group having 1 to 12 carbon atoms, which is a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, or an isobutylene. Examples thereof include a group, sec-butylene group, tert-butylene group, n-pentylene group, isopentylene group, neopentylene group, tert-pentylene group and the like.
Examples of the alkyl group indicated by R ^D20 include groups similar to the alkyl groups indicated by ^{R D11 to} R ^D17.

In the formula (D-1), the aryl group represented by R ^D18, for example, a phenyl group, methylphenyl group, dimethylphenyl group, an ethylphenyl group, and the like.
The ^{aryl group indicated by RD18} is preferably an alkyl-substituted aryl group substituted with an alkyl group from the viewpoint of solubility. ^Examples of the alkyl group of the alkyl-substituted aryl group include groups similar to the alkyl group shown by ^{R D11 to} R D17.

In the formula ^(D-1), the aralkyl group represented by ^{R D18,} include groups represented by ^-L D21 -Ar. However, ^LD21 represents an alkylene group and Ar represents an aryl group.
^Examples of the alkylene group indicated by LD21 include a linear or branched alkylene group having 1 to 12 carbon atoms, which is a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, or an isobutylene. Examples thereof include a group, sec-butylene group, tert-butylene group, n-pentylene group, isopentylene group, neopentylene group, tert-pentylene group and the like.
Examples of the aryl group indicated by Ar include a phenyl group, a methylphenyl group, a dimethylphenyl group, an ethylphenyl group and the like.

In the formula (D-1), specifically aralkyl group represented by R ^D18, benzyl, methylbenzyl, dimethylbenzyl, phenylethyl group, methyl phenylethyl group, phenylpropyl group, phenylbutyl group and the like Can be mentioned.

The the compound represented by the general formula (D-1), from the viewpoint of high sensitivity, the electron transporting material R ^D18 is an alkyl group or an aralkyl group having 5 to 10 carbon atoms are preferred, in particular, R ^D11 to R ^{A compound in which D17} independently represents a hydrogen atom, a halogen atom, or an alkyl group, and ^RD18 represents an alkyl group or an aralkyl group having 5 or more and 10 or less carbon atoms is preferable.

Hereinafter, exemplary compounds of the compounds represented by the general formula (D-1) will be shown, but the present invention is not limited thereto.

The abbreviations in the above-exemplified compounds have the following meanings.
・ Ph: Phenyl group

As the compound represented by the general formula (D-1), one type may be used alone, or two or more types may be used in combination.

Specific examples of the electron-transporting material include the electron-transporting materials represented by the general formulas (C-1) and (D-1), and other electron-transporting materials, for example, the following structural formula (ET-A). The compounds represented by ~ (ET-E) are also mentioned.

The content of the total electron transport material with respect to the total solid content of the photosensitive layer is preferably 4% by mass or more and 30% by mass or less, preferably 6% by mass or more and 25% by mass or less, and more preferably 8% by mass or more and 20% by mass or less. be. The content of the electron transporting material is the total content of the electron transporting materials when two or more kinds of electron transporting materials are used in combination.

-Other ingredients-
The monolayer type photosensitive layer may contain other well-known additives such as a surfactant, an antioxidant, a light stabilizer, and a heat stabilizer. When the single-layer type photosensitive layer is a surface layer (that is, the outermost layer), the single-layer type photosensitive layer may contain a release agent such as fluororesin particles or a silicone polymer.

The electrophotographic photosensitive member may be a positively charged electrophotographic photosensitive member or a negatively charged electrophotographic photosensitive member, but from the viewpoint of more exerting the effect of the present embodiment, the electrophotographic photosensitive member may be a positively charged electron. It is preferably a photographic photosensitive member.
The single-layer photosensitive layer in the positively charged electrophotographic photosensitive member preferably contains a charge control agent as another component, and more preferably contains an electron donating charge control agent. When an electron-donating charge control agent is contained, a positively charged photosensitive layer is easily formed. As the charge control agent, a conventionally known compound used as a charge control agent for toner is used.
Examples of the electron donating charge control agent include an azo metal type charge control agent, an oxycarboxylic acid type charge control agent, a boron complex type charge control agent, an iron complex type charge control agent, a zinc complex type charge control agent, and an alkylsalicylic acid complex salt. Examples thereof include a system charge control agent and a sulfonic acid pendant resin type charge control agent.
The charge control agent may be used alone or in combination of two or more.
The content of the charge control agent, particularly the electron donating charge control agent, is preferably 0.01 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin of the photosensitive layer, and 0.05 parts by mass. It is more preferably 10 parts by mass or less, and further preferably 0.1 parts by mass or more and 5 parts by mass or less.

(Characteristics of photosensitive layer)
The photosensitive layer according to the present embodiment is derived from the carbonyl group of the polycarbonate resin on the surface of the photosensitive layer, which is measured by an infrared spectrophotometer (IR) from the viewpoint of improving the abrasion resistance of the photoconductor and suppressing the color point. ^{The peak intensity (P2F) of the fingerprint region (695 cm -1} ) peculiar to the hole transport material with respect to the peak intensity (1775 cm ^{-1) (P1F) of the When the peak intensity (P2B) of the fingerprint region (695 cm -1} ) peculiar to the hole transport material with respect to ^{the peak intensity (1775 cm -1} ) (P1B) derived from the carbonyl group of the polycarbonate resin is (PB), the above (PF) And (PB) satisfy the relationship of the following equation (1).
From the viewpoint of improving the abrasion resistance of the photoconductor and suppressing the color point, the (PF) and (PB) preferably satisfy the relationship of the following formula (2), and satisfy the relationship of the following formula (3). Is more preferable.
-Equation (1): 0.2 ≤ (PF) / (PB) ≤ 0.37
-Equation (2): 0.2 ≤ (PF) / (PB) ≤ 0.30
Equation (3): 0.2 ≤ (PF) / (PB) ≤ 0.25

Further, in the photosensitive layer according to the present embodiment, the above (PF) and (PB) satisfy the relationship of the formula (4) from the viewpoint of improving the abrasion resistance of the photoconductor and suppressing the color point.
From the viewpoint of improving the abrasion resistance of the photoconductor and suppressing the color point, the (PF) and (PB) preferably satisfy the relationship of the following formula (5), and satisfy the relationship of the following formula (6). Is more preferable.
Equation (4): 0.18 ≤ (PB)-(PF) ≤ 0.47
Equation (5): 0.20 ≤ (PB)-(PF) ≤ 0.46
Equation (6): 0.40 ≤ (PB)-(PF) ≤ 0.45

The (PF) is measured by the following method.
The above (PF) is obtained by measuring by FTIR-ATR (total reflection absorption infrared spectroscopy) method.
First, a disk-shaped measurement sample having a diameter of 5 cm and a thickness of about 2 mm is cut out from the surface of the photosensitive layer. Then, the wave number of the measurement sample is measured by an infrared spectrophotometer (manufactured by JASCO Corporation: FT / IR-6100, ATR unit, with window material ZnSe) under ^{the conditions of 64 integration times and a resolution of 4 cm -1.} after measurement of 650 cm ^-1 or more 4000 cm ^-1 or less in the range, to obtain an infrared absorption spectrum by performing an ATR correction.
From the obtained infrared absorption spectrum, the peak ^{intensity (1775 cm -1} ) derived from the carbonyl group of the polycarbonate resin (P1F) and the peak intensity (P2F) of the fingerprint region (695 cm ^{-1) peculiar to the hole transport material were used.} , Let (PF) be the value obtained by the following formula (7).
-Equation (7): (PF) = (P2F) / (P1F)

The (PB) is measured by the following method.
The above (PB) can be obtained by measuring by the FTIR-ATR (total reflection absorption infrared spectroscopy) method.
First, a disk-shaped measurement sample having a diameter of 5 cm and a thickness of about 2 mm is cut out from the surface of the photosensitive layer on the conductive substrate side. Then, the wave number of the measurement sample is measured by an infrared spectrophotometer (manufactured by JASCO Corporation: FT / IR-6100, ATR unit, with window material ZnSe) under ^{the conditions of 64 integration times and a resolution of 4 cm -1.} after measurement of 650 cm ^-1 or more 4000 cm ^-1 or less in the range, to obtain an infrared absorption spectrum by performing an ATR correction.
From the obtained infrared absorption spectrum, the peak ^{intensity (1775 cm -1} ) derived from the carbonyl group of the polycarbonate resin (P1B) and the peak intensity (P2B) of the fingerprint region (695 cm ^{-1) peculiar to the hole transport material were used.} , Let (PB) be the value obtained by the following formula (8).
-Equation (8): (PB) = (P2B) / (P1B)

The film thickness of the single-layer type photosensitive layer is preferably set in the range of 5 μm or more and 60 μm or less, more preferably 5 μm or more and 50 μm or less, and further preferably 10 μm or more and 40 μm or less.

(Formation of a single-layer photosensitive layer)
The single-layer type photosensitive layer is formed by using a coating liquid for forming a photosensitive layer in which the above components are added to a solvent.
Solvents include aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene, ketones such as acetone and 2-butanone, halogenated aliphatic hydrocarbons such as methylene chloride, chloroform and ethylene chloride, tetrahydrofuran and ethyl ether. Examples thereof include ordinary organic solvents such as cyclic or linear ethers such as. These solvents are used alone or in combination of two or more.

In order to obtain a photosensitive layer having high wear resistance, it is preferable to use a mixture of two kinds of solvents as the solvent used in the coating liquid for forming the photosensitive layer.

As the two types of solvents, for example, toluene and tetrahydrofuran are used, and the ratio of the content of tetrahydrofuran to the content of toluene is 1 or more and 4 or less, so that (PF) and (PB) are 0. A photoconductor that satisfies the relationship of 2 ≦ (PF) / (PB) ≦ 0.37 or 0.18 ≦ (PB) − (PF) ≦ 0.47 can be obtained.

As a method of dispersing particles (for example, a charge generating material) in a coating liquid for forming a photosensitive layer, a media disperser such as a ball mill, a vibrating ball mill, an attritor, a sand mill, or a horizontal sand mill, a stirring, an ultrasonic disperser, a roll mill, etc. A medialess disperser such as a high-pressure homogenizer is used. Examples of the high-pressure homogenizer include a collision method in which a dispersion liquid is dispersed by a liquid-liquid collision or a liquid-wall collision in a high-pressure state, and a penetration method in which a dispersion liquid is dispersed by penetrating a fine flow path in a high-pressure state.

Examples of the method for applying the coating liquid for forming a photosensitive layer include a dipping coating method, a push-up coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, and a curtain coating method.

[Image forming device (and process cartridge)]
The image forming apparatus according to the present embodiment includes an electrophotographic photosensitive member, a charging means for charging the surface of the electrophotographic photosensitive member, and an electrostatic latent image forming on the surface of the charged electrophotographic photosensitive member. Means, a developing means for developing an electrostatic latent image formed on the surface of an electrophotographic photosensitive member with a developer containing toner to form a toner image, and a transfer means for transferring the toner image to the surface of a recording medium. To be equipped with. Then, as the electrophotographic photosensitive member, the electrophotographic photosensitive member according to the present embodiment is applied.

The image forming apparatus according to the present embodiment is an apparatus provided with fixing means for fixing the toner image transferred to the surface of the recording medium; direct transfer for directly transferring the toner image formed on the surface of the electrophotographic photosensitive member to the recording medium. Device of the method; Intermediate transfer in which the toner image formed on the surface of the electrophotographic photosensitive member is primarily transferred to the surface of the intermediate transfer body, and the toner image transferred to the surface of the intermediate transfer body is secondarily transferred to the surface of the recording medium. Device of the method; A device equipped with a cleaning means for cleaning the surface of the electrophotographic photosensitive member after the transfer of the toner image and before charging; the surface of the electrophotographic photosensitive member is irradiated with xerographic light after the transfer of the toner image and before charging. A device provided with a static elimination means for removing static electricity; a well-known image forming device such as a device provided with an electrophotographic photosensitive member heating member for raising the temperature of the electrophotographic photosensitive member and reducing the relative temperature is applied.

In the case of an intermediate transfer type apparatus, the transfer means is, for example, a primary transfer body in which a toner image is transferred to the surface and a primary transfer of a toner image formed on the surface of an electrophotographic photosensitive member to the surface of the intermediate transfer body. A configuration having a transfer means and a secondary transfer means for secondary transfer of the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium is applied.

From the viewpoint of improving the wear resistance of the photoconductor and suppressing the color point, the image forming apparatus is a charging means having a scorotron charger as the charging means, and the developing means uses a non-magnetic one-component developer, and the above is performed together with the development. It is a developing means for cleaning the electrophotographic photosensitive member, and it is preferable that the transfer means is an image forming apparatus which is a transfer means of a direct transfer method for directly transferring a toner image to the surface of a recording medium.

The reason is that since the scorotron charger is non-contact, fatigue wear due to contact between members is suppressed as compared with a contact type charging roller. Further, in the simultaneous development cleaning, as compared with the cleaning method using a cleaning blade, the phenomenon that the photosensitive layer is abraded due to contact with the blade and the toner is interposed between the blade and the photosensitive layer suppresses the phenomenon that the photosensitive layer is scraped. .. This is because the non-magnetic one-component development does not include carriers, so that the phenomenon that the carriers are transferred to the photosensitive layer and scrape the photosensitive layer is suppressed.

The image forming apparatus according to the present embodiment may be either a dry developing type image forming apparatus or a wet developing type (developing method using a liquid developer) image forming apparatus.

In the image forming apparatus according to the present embodiment, for example, the portion including the electrophotographic photosensitive member may have a cartridge structure (process cartridge) that is attached to and detached from the image forming apparatus. As the process cartridge, for example, a process cartridge including the electrophotographic photosensitive member according to the present embodiment is preferably used. In addition to the electrophotographic photosensitive member, the process cartridge may include at least one selected from the group consisting of, for example, charging means, electrostatic latent image forming means, developing means, and transfer means.

Hereinafter, an example of the image forming apparatus according to the present embodiment will be shown, but the present invention is not limited thereto. The main parts shown in the figure will be described, and the other parts will be omitted.

FIG. 2 is a schematic configuration diagram showing an example of an image forming apparatus according to the present embodiment.
As shown in FIG. 2, the image forming apparatus 100 according to the present embodiment includes a process cartridge 300 including an electrophotographic photosensitive member 7, an exposure apparatus 9 (an example of an electrostatic latent image forming means), and a transfer apparatus 40 (primary). A transfer device) and an intermediate transfer body 50 are provided. In the image forming apparatus 100, the exposure apparatus 9 is arranged at a position where the electrophotographic photosensitive member 7 can be exposed to the electrophotographic photosensitive member 7 from the opening of the process cartridge 300, and the transfer apparatus 40 is arranged via the intermediate transfer body 50 to the electrophotographic photosensitive member. The intermediate transfer body 50 is arranged at a position facing the electrophotographic photosensitive member 7, and a part of the intermediate transfer body 50 is arranged in contact with the electrophotographic photosensitive member 7. Although not shown, it also has a secondary transfer device that transfers the toner image transferred to the intermediate transfer body 50 to a recording medium (for example, paper). The intermediate transfer body 50, the transfer device 40 (primary transfer device), and the secondary transfer device (not shown) correspond to an example of the transfer means.

The process cartridge 300 in FIG. 2 has an electrophotographic photosensitive member 7, a charging device 8 (an example of charging means), a developing device 11 (an example of developing means), and a cleaning device 13 (an example of cleaning means) integrated in a housing. Supports. The cleaning device 13 has a cleaning blade (an example of a cleaning member) 131, and the cleaning blade 131 is arranged so as to come into contact with the surface of the electrophotographic photosensitive member 7. The cleaning member may be a conductive or insulating fibrous member instead of the mode of the cleaning blade 131, and may be used alone or in combination with the cleaning blade 131.

In addition, in FIG. 2, as an image forming apparatus, a fibrous member 132 (roll shape) that supplies the lubricant 14 to the surface of the electrophotographic photosensitive member 7 and a fibrous member 133 (flat brush shape) that assists cleaning are shown. Examples are shown, but these are arranged as needed.

Hereinafter, each configuration of the image forming apparatus according to the present embodiment will be described.

-Charging device-
As the charging device 8, for example, a contact-type charging device using a conductive or semi-conductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube, or the like is used. Further, a non-contact type roller charger, a scorotron charger using corona discharge, a corotron charger, or the like, which is known per se, is also used.

-Exposure device-
Examples of the exposure apparatus 9 include an optical system device that exposes light such as a semiconductor laser beam, an LED light, and a liquid crystal shutter light on the surface of the electrophotographic photosensitive member 7 in a predetermined image pattern. The wavelength of the light source is within the spectral sensitivity region of the electrophotographic photosensitive member. The mainstream wavelength of a semiconductor laser is near infrared, which has an oscillation wavelength in the vicinity of 780 nm. However, the wavelength is not limited to this, and a laser having an oscillation wavelength in the 600 nm range or a laser having an oscillation wavelength of 400 nm or more and 450 nm or less may be used as a blue laser. Further, a surface emitting type laser light source capable of outputting a multi-beam is also effective for forming a color image.

-Developer-
Examples of the developing device 11 include a general developing device that develops by contacting or not contacting a developing agent. The developing device 11 is not particularly limited as long as it has the above-mentioned functions, and is selected according to the purpose. For example, a known developer having a function of adhering a one-component developer or a two-component developer to the electrophotographic photosensitive member 7 using a brush, a roller, or the like can be mentioned. Of these, those using a developing roller in which the developing agent is held on the surface are preferable.

From the viewpoint of improving the abrasion resistance of the photoconductor and suppressing the color point, it is more preferable to use a developing means for cleaning the electrophotographic photosensitive member at the same time as developing.
The developing means for cleaning the electrophotographic photosensitive member at the same time as developing is specifically that by optimizing the setting conditions of the developing bias of the developing roller of the developing apparatus 11, the transfer residual toner is transferred to the developing roller of the developing apparatus 11. When it reaches the opposite portion (development unit), it is a developing means that is collected (cleaned) by the developing apparatus 11 by an electrostatic attraction at the same time as developing.

The developer used in the developing apparatus 11 may be a one-component developer using only toner or a two-component developer containing toner and a carrier. Further, the developer may be magnetic or non-magnetic. Well-known developer is applied.

-Cleaning device-
As the cleaning device 13, a cleaning blade type device including a cleaning blade 131 is used.
In addition to the cleaning blade method, a fur brush cleaning method and a simultaneous development cleaning method may be adopted.

-Transfer device-
Examples of the transfer device 40 include contact-type transfer chargers using belts, rollers, films, rubber blades, etc., scorotron transfer chargers using corona discharge, and transfer chargers known per se, such as corotron transfer chargers. Can be mentioned.

-Intermediate transcript-
As the intermediate transfer body 50, a belt-shaped one (intermediate transfer belt) containing semi-conductive polyimide, polyamide-imide, polycarbonate, polyarylate, polyester, rubber, or the like is used. Further, as the form of the intermediate transfer body, a drum-shaped one may be used in addition to the belt-shaped one.

FIG. 3 is a schematic configuration diagram showing another example of the image forming apparatus according to the present embodiment.
The image forming apparatus 120 shown in FIG. 3 is a tandem type multicolor image forming apparatus equipped with four process cartridges 300. In the image forming apparatus 120, four process cartridges 300 are arranged in parallel on the intermediate transfer body 50, and one electrophotographic photosensitive member is used for each color. The image forming apparatus 120 has the same configuration as the image forming apparatus 100 except that it is a tandem type.

Examples will be described below, but the present invention is not limited to these examples. In the following description, unless otherwise specified, "parts" and "%" are all based on mass.

<Example 1>
45.75 parts of the polycarbonate resin (1) shown in Table 1 as the binder resin and 1.25 parts of CGM (1) which is the hydroxygallium phthalocyanine (V type) pigment shown in Table 1 as the charge generating material. 9 parts of ETM (1), which is an electron transport material shown in Table 1, 44 parts of HTM (1), which is a hole transport material shown in Table 1, 175 parts of tetrahydrofuran and 75 parts of toluene as a solvent. And were mixed and dispersed in a sand mill for 4 hours using glass beads having a diameter of 1 mmφ to obtain a coating liquid for forming a photosensitive layer.

The obtained coating liquid for forming a photosensitive layer is applied onto an aluminum substrate having a diameter of 30 mm, a length of 244.5 mm, and a wall thickness of 1 mm by an immersion coating method, and dried and cured at 110 ° C. for 40 minutes to obtain a thickness. A 36 μm single-layer photosensitive layer was formed.
As described above, the photoconductor of Example 1 was obtained.

<Examples 2 to 17>
In the same manner as in Example 1, each example was described in the same manner as in Example 1 except that the type, amount (number of copies) and drying and curing conditions of the polycarbonate resin, charge generating material, electron transporting material, hole transporting material and solvent were changed according to Table 1. A photoconductor was obtained.

<Comparative Examples 1 to 11>
In the same manner as in Example 1, each example was described in the same manner as in Example 1 except that the type, amount (number of copies) and drying and curing conditions of the polycarbonate resin, charge generating material, electron transporting material, hole transporting material and solvent were changed according to Table 2. A photoconductor was obtained.

The photoconductors obtained in Examples and Comparative Examples are subjected to a printer (the charging means is a charging means having a scorotron charger, and the developing means uses a non-magnetic one-component developer to clean the electrophotographic photosensitive member together with development. The image forming apparatus, which is a developing means and a transfer means, which is a direct transfer type transfer means for directly transferring a toner image to the surface of a recording medium, manufactured by Brother Industries, Ltd., HL-L6400DW), is charged under the following conditions. Characteristic evaluation, abrasion resistance evaluation, and color point evaluation were performed.

<Evaluation of charging characteristics>
The slope of the photoconductor charging potential (VH) with respect to the grid electrode (Vg) when a voltage is applied to the scorotron grid electrode every 50 V from 400 V to 700 V under the conditions of a temperature of 32.5 ° C. and a humidity of 80% RH. α was evaluated, and the charging characteristics were evaluated according to the following evaluation criteria.

-Evaluation criteria-
A: 0.99 ≤ α
B: 0.98 ≤ α <0.99
C: 0.97 ≤ α <0.98
D: α <0.97

<Abrasion resistance evaluation>
Under the conditions of a temperature of 32.5 ° C. and a humidity of 80% RH, 10,000 repetitive images are formed, and the film thickness of the photosensitive layer before the repetitive image is formed and the film thickness after 10,000 repetitive images are formed. The difference was measured, the wear rate (μm / 1 kPV) was calculated, and the wear resistance was evaluated according to the following evaluation criteria.

-Evaluation criteria-
A: Less than 0.05 μm / 1 kPV B: 0.05 μm / 1 kPV or more and less than 1.0 μm / 1 kPV C: 1.0 μm / 1 kPV or more and less than 1.25 μm / 1 kPV D: 1.25 μm / 1 kPV or more

<Color point evaluation>
In the color point evaluation, 10,000 images with 5% area coverage were output under the conditions of a temperature of 32.5 ° C. and a humidity of 80% RH, and then five full-scale images with 0% area coverage were output. The number of color spots generated at the circumference pitch was counted, and the color spots were evaluated according to the following evaluation criteria.
-Evaluation criteria-
A: Less than 1 B: 3 or more and less than 6 C: 6 or more and less than 9 D: 10 or more

The details of the abbreviations in Tables 1 and 2 are shown below.
Resin (1): Polycarbonate resin which is a homopolymer (polycarbonate resin of bisphenol Z (PCZ: polycarbonate resin having a structural unit represented by the structural formula (PC-3)), viscosity average molecular weight Mv = 40,000)
Resin (2): Polycarbonate resin which is a biphenyl copolymer (biphenyl copolymer type polycarbonate resin having a structural unit represented by the structural formula (PC-1)), viscosity average molecular weight Mv = 45000)
CGM (1): Hydroxygallium phthalocyanine (V type) pigment. CuKα characteristic X-rays have diffraction peaks at at least 7.3 °, 16.0 °, 24.9 °, and 28.0 ° Bragg angles (2θ ± 0.2 °) in the X-ray diffraction spectrum. (Maximum peak wavelength = 820 nm, average particle size = 0.12 μm, maximum particle size = 0.2 μm, BET specific surface area value = 60 m ² / g in the spectral absorption spectrum in the wavelength range of 600 nm or more and 900 nm or less).
ETM (1): A compound represented by the structural formula (C-1-3).
ETM (2): A compound represented by the structural formula (D-1-2).
HTM (1): A compound represented by the structural formula (HT-1).
HTM (2): A compound represented by the structural formula (HT-11).
HTM (3): A compound represented by the structural formula (HT-4).

“Ratio (THF / Tol)” in Tables 1 and 2 indicates the ratio of the contents of tetrahydrofuran and toluene used as a solvent. The number on the left indicates the content of tetrahydrofuran, and the number on the right indicates the content of toluene.

From the above results, it can be seen that the photoconductor of this example has higher wear resistance than the photoconductor of the comparative example.
It can also be seen that the photoconductor of this example has good charging characteristics and color spot suppressing effect.

1 Undercoat layer, 2 Photosensitive layer, 3 Conductive substrate, 7 Electrophotographic photosensitive member, 8 Charging device, 9 Exposure device, 11 Developing device, 13 Cleaning device, 14 Lubricant, 40 Transfer device, 50 Intermediate transfer device, 100 Image forming device, 120 Image forming device, 131 Cleaning blade, 132 Fibrous member (roll type), 133 Fibrous member (flat brush type), 300 Process cartridge

Claims (8)

With a conductive substrate
It is a single-layer type photosensitive layer provided on the conductive substrate, and has a photosensitive layer containing a polycarbonate resin, a charge generating material, a hole transporting material having a triarylamine structure, and an electron transporting material. ,
The hole transport material-specific fingerprint region (695 cm ^{-1 ) with respect to the peak intensity (1775 cm -1} ) (P1F) derived from the carbonyl group of the polycarbonate resin on the surface of the photosensitive layer as measured by an infrared spectrophotometer (IR). ) Is the peak intensity (P2F) of (PF), which is unique to the hole transport material with respect to ^{the peak intensity (1775 cm -1} ) (P1B) derived from the carbonyl group of the polycarbonate resin on the surface of the photosensitive layer on the conductive substrate side. When the peak intensity (P2B) of the fingerprint region (695 cm ^-1 ) is (PB), the above (PF) and (PB) satisfy the relationship of 0.2 ≦ (PF) / (PB) ≦ 0.37. Electrophotophotoreceptor. The electrophotographic photosensitive member according to claim 1, wherein the hole transport material is a compound represented by the following general formula (a-2).

(In the structural formula ^{(a-2), R T91} and ^{R T92 .R} each showing independently a hydrogen atom, a halogen atom, 1 to 5 carbon atoms in the alkyl group, or a number of 1 to 5 alkoxy group carbon ^T101 , ^{R T102, R T111} and ^{R T112} are each independently substituted with a halogen atom, 1 to 5 carbon atoms in the alkyl group, 1 to 5 carbon atoms in the alkoxy group, 1 to 2 of alkyl groups having a carbon number Amino group, substituted or unsubstituted aryl group, -C ( ^RT12 ) = C ( ^RT13 ) ( ^RT14 ), or -CH = CH-CH = C ( ^RT15 ) ( ^RT16 ), indicating ^{RT12 , R T13, R T14, R} T15 and ^{R T16} are each independently a hydrogen atom, .Tm1 a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, Tm2, 0 Tn1 and Tn2 are each independently An integer of 2 or more is shown.) The electrophotographic photosensitive member according to claim 2, wherein the hole transport material is a compound represented by the following formula HT-1.

The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the content of the hole transporting material is 10% by mass or more and 50% by mass or less with respect to the total solid content of the photosensitive layer. .. The electrophotographic photosensitive member according to claim 4, wherein the content of the hole transporting material is 38% by mass or more and 48% by mass or less with respect to the total solid content of the photosensitive layer. With a conductive substrate
It is a single-layer type photosensitive layer provided on the conductive substrate, and has a photosensitive layer containing a polycarbonate resin, a charge generating material, a hole transporting material having a triarylamine structure, and an electron transporting material. ,
The hole transport material-specific fingerprint region (695 cm ^{-1 ) with respect to the peak intensity (1775 cm -1} ) (P1F) derived from the carbonyl group of the polycarbonate resin on the surface of the photosensitive layer as measured by an infrared spectrophotometer (IR). ) Is the peak intensity (P2F) of (PF), which is unique to the hole transport material with respect to ^{the peak intensity (1775 cm -1} ) (P1B) derived from the carbonyl group of the polycarbonate resin on the surface of the photosensitive layer on the conductive substrate side. When the peak intensity (P2B) of the fingerprint region (695 cm ^-1 ) is (PB), the above (PF) and (PB) satisfy the relationship of 0.18 ≦ (PB) − (PF) ≦ 0.47. Electrophotophotoreceptor. The electrophotographic photosensitive member according to any one of claims 1 to 6.
A charging means for charging the surface of the electrophotographic photosensitive member and
An electrostatic latent image forming means for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member,
A developing means for developing an electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image, and a developing means.
A transfer means for transferring the toner image to the surface of a recording medium,
An image forming apparatus comprising. The charging means is a charging means having a scorotron charger.
The developing means is a developing means that uses a non-magnetic one-component developer to clean the electrophotographic photosensitive member at the same time as developing.
The image forming apparatus according to claim 7, wherein the transfer means is a direct transfer type transfer means for directly transferring the toner image to the surface of the recording medium.

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