JP2005091838A - Organic compound, electrophotographic photoreceptor, process cartridge, image forming apparatus, and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which enables stable obtaining of clear electrophotographic images of high density and high definition, by preventing the degradation in image density caused by the degradation in sensitivity, i.e. degradation in image density due to the potential fluctuation in a solid black image section by an inversion phenomenon and the occurrence of character thinning etc., liable to arise in high-speed copying or under a low-temperature and low-humidity environment at the forming of an electrophotographic image, and a process cartridge which uses the electrophotographic photoreceptor, an image forming method and an image forming apparatus. <P>SOLUTION: The organic compound is expressed by general Formula (1). In the general Formula (1), R1 to R11 represent hydrogen atoms, substituted or non-substituted alkyl groups, alkoxy groups or halogen atoms; Ar1 to Ar4 represent substituted or non-substituted aryl groups, aralkyl group, wherein Ar1 and Ar2, and Ar3 and Ar4 may respectively bond to each other to form rings; (k), (l) and (m) respectively represent an integer from 1 to 4; (n) represents an integer of ≥1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a novel organic compound, and an electrophotographic photosensitive member, a process cartridge, an image forming apparatus, and an image forming method using the organic compound, and more specifically, an electrophotographic system used in the field of copying machines and printers. The present invention relates to an electrophotographic photosensitive member, a process cartridge, an image forming apparatus, and an image forming method used for image formation.

  The electrophotographic photosensitive member (hereinafter, also simply referred to as a photosensitive member) has a wider range of materials selection than the inorganic photosensitive member such as a selenium-based photosensitive member and an amorphous silicon photosensitive member, and is excellent in environmental suitability. There are significant advantages such as low production costs, and in recent years, organic photoreceptors have become the mainstream in place of inorganic photoreceptors.

On the other hand, in recent electrophotographic image forming methods, as a hard copy printer of a personal computer, and in an ordinary copying machine, image processing of LEDs and lasers is easy due to the ease of image processing and deployment to a multifunction machine. A digital image forming system that uses a light source has rapidly spread. Furthermore, a technique for producing a high-quality electrophotographic image by developing a finer digital image has been developed. For example, image exposure is performed with a laser beam having a small spot area, the density of the dot latent image is increased, a high-definition latent image is formed, the latent image is developed with a small particle size toner, and a high-quality electrophotographic image The technology for producing is disclosed. (Patent Document 1)
In forming such a high-quality digital image, an electrophotographic photosensitive member having high sensitivity and stable characteristics against changes in the greenhouse environment is required.

  Conventionally, in order to satisfy the requirements for the electrophotographic photoreceptor as described above, the electrophotographic photoreceptor has a layer structure in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer, and the charge transport layer has a molecular weight of about 500. The charge transporting substance having a low molecular weight is contained in a large amount. Among them, a charge transport material having a styryltriphenylamine structure has been put into practical use as a compound having excellent charge transportability (Patent Document 2). However, in the charge transport layer having such a structure, the film quality is lowered, and the surface The charge transport layer of the layer is easily contaminated with foreign substances. That is, the surface of the photosensitive member is easily contaminated with paper dust or a toner composition by a developing unit, a transferring unit, a cleaning unit, and the like arranged around the photosensitive member. As a result, a black spot (a wrinkled spot image) or a transfer Periodic image defects such as missing are likely to occur. In addition, in a high-speed copying machine or a low-temperature and low-humidity environment where the time between the exposure process and the development process is short, sufficient sensitivity cannot be obtained, and as a result, the dot image is not reproduced faithfully, and the image in which fine lines are cut is obtained. It is easy to occur.

  In addition, it has been reported that a charge transport material having a higher molecular weight is used as a method for solving such a problem. For example, an electrophotographic photosensitive member containing a charge transport material having a bisstyryl chemical structure has been reported (Patent Documents 3 and 4). However, even if these charge transport materials are used in the charge transport layer, sufficient sensitivity cannot be obtained in a high-speed copying machine or a low temperature and low humidity environment where the time between the exposure process and the development process is short, and as a result, Dot images are not faithfully reproduced, and an image in which fine lines are cut is likely to be generated. In addition, the charge transport layer is likely to have insufficient compatibility with the binder resin, the charge transport material is not uniformly dispersed, and the sensitivity is not sufficient, and at the same time, the charge transport layer is liable to be broken.

In order to prevent contamination of the surface of the photoreceptor, an electrophotographic photoreceptor having a surface layer containing fluorine-based resin particles has been proposed (Patent Document 5). However, an electrophotographic photosensitive member containing fluorine resin particles tends to cause image blur. Also, the mechanical strength of the surface layer is likely to be lowered, and the surface of the photoreceptor is easily worn by contact friction with the cleaning means or the like, and a good electrophotographic image cannot always be provided.
Japanese Patent Laid-Open No. 2001-255585 JP-A-60-196768 JP-A-3-149560 JP-A-10-207093 JP-A-63-65449

  The present invention has been proposed in order to solve the above-mentioned problems. The object of the present invention is to form a novel organic compound useful for improving the characteristics of an electrophotographic photosensitive member, when forming an electrophotographic image. An electrophotographic photosensitive member that is less likely to occur in high-speed copying and low-temperature, low-humidity environments, and that prevents a decrease in image density due to potential fluctuations in the solid black image portion due to a decrease in sensitivity and a decrease in sharpness due to occurrence of character thinning, and the like An object is to provide a process cartridge, an image forming method, and an image forming apparatus using an electrophotographic photosensitive member. In addition, an electrophotographic photosensitive member that prevents periodic image defects such as black spots and transfer spots that are likely to occur due to surface contamination of the electrophotographic photosensitive member, a process cartridge that uses the electrophotographic photosensitive member, an image forming method, and an image It is to provide a forming apparatus. In addition, an electrophotographic photosensitive member capable of stably obtaining a clear electrophotographic image having a high density and high resolution without causing breakage such as cracks, and a process cartridge and an image using the electrophotographic photosensitive member A forming method and an image forming apparatus are provided.

  As a result of intensive studies, the present inventors have conducted detailed studies on the binder resin and the charge transport material constituting the charge transport layer of the electrophotographic photosensitive member in order to solve the above problems of the present invention. Good compatibility with resin, improved response of sensitivity in high-speed process and low-temperature and low-humidity environment, surface layer is less likely to be contaminated, and eliminates periodic image defects such as black spots and transfer defects. The present invention has been completed by finding a novel organic compound that can prevent and prevent the occurrence of breakage such as cracks and the like and can stably obtain a clear image with high density and high resolution.

The object of the present invention is achieved by adopting one of the following configurations.
(Claim 1)
An organic compound represented by the following general formula (1):

In general formula (1), R _{1 to} R ₁₁ represent a hydrogen atom, a substituted or unsubstituted alkyl group, an alkoxy group or a halogen atom, and Ar _{1 to} Ar ₄ represent a substituted or unsubstituted aryl group or an aralkyl group. . However, Ar ₁ and Ar ₂ , Ar ₃ and Ar ₄ may be bonded to each other to form a ring. k, l and m each represent an integer of 1 to 4, and n represents an integer of 1 or more.
(Claim 2)
An electrophotographic photoreceptor comprising the organic compound represented by the general formula (1).
(Claim 3)
An electrophotographic photosensitive member comprising a charge generation layer and a charge transport layer on a conductive support, wherein the charge transport layer contains the organic compound represented by the general formula (1).
(Claim 4)
Electrophotographic photosensitive member containing the organic compound of the general formula (1), charging means for uniformly charging the electrophotographic photosensitive member, and latent image formation for forming an electrostatic latent image on the charged electrophotographic photosensitive member Developing means for developing an electrostatic latent image on the electrophotographic photosensitive member; transfer means for transferring a toner image visualized on the electrophotographic photosensitive member onto a transfer material; At least one of a charge eliminating means for removing the charge on the photographic photosensitive member and a cleaning means for removing the toner remaining on the electrophotographic photosensitive member after transfer is integrally supported, and is detachably attached to the image forming apparatus main body. A process cartridge that can be attached to a cartridge.
(Claim 5)
An image forming apparatus comprising the process cartridge according to claim 4.
(Claim 6)
An image forming method comprising forming an electrophotographic image using the image forming apparatus according to claim 5.

  By using the organic compound, electrophotographic photosensitive member, process cartridge, image forming method and image forming apparatus of the present invention, image defects due to poor sensitivity such as high-speed adaptability, which are likely to occur in low-temperature and low-humidity environments, and high-temperature and high-humidity Therefore, it is possible to provide an electrophotographic image with good image density and sharpness.

  Hereinafter, the present invention will be described in detail.

Structure of electrophotographic photoreceptor The electrophotographic photoreceptor used in the present invention is characterized by containing the organic compound represented by the general formula (1).

  The electrophotographic photosensitive member used in the present invention has a charge generation layer and a charge transport layer on a conductive support, and the charge transport layer contains the compound of the general formula (1) as a charge transport material. It is characterized by doing.

  The electrophotographic photosensitive member of the present invention has the above-described configuration, and can prevent sharpness reduction such as thinning due to sensitivity reduction, which is likely to occur in high-speed copying and low-temperature and low-humidity environments. In addition, no periodic image defects such as transfer defects are generated, and no flaws such as cracks are generated, so that a clear electrophotographic image having a high density and a high resolving power can be produced.

  Hereinafter, an electrophotographic photoreceptor using the compound of the general formula (1) as a charge transport material will be described.

In the general formula (1), R _{1 to} R ₁₁ represent a hydrogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, or a halogen atom, and the substituted or unsubstituted alkyl group or alkoxy group has 1 carbon atom. The alkyl group and alkoxy group of -4 are preferable, and as a halogen atom, a chlorine atom, a bromine atom, and a fluorine atom are preferable.

On the other hand, Ar _{1 to} Ar ₄ represent a substituted or unsubstituted aryl group or aralkyl group. Preferred examples of the substituent include an alkyl group having 1 to 4 carbon atoms, an alkoxy group, and a halogen atom. Ar ₁ and Ar ₂ , Ar ₃ and Ar ₄ may be bonded to each other to form a ring. k, l and m each represent an integer of 1 to 4, and n represents an integer of 1 or more. n is preferably 1 to 3.

  Examples of preferred compounds of the general formula (1) are listed below.

  Below, the synthesis example of the compound of this invention is described.

  In the following synthesis examples, raw materials and the like will be described using the numbers given in the compound synthesis mechanism (scheme).

  Synthesis Example (1); Synthesis of Compound T-2

  A 100 ml four-headed flask was equipped with a nitrogen inlet tube, a condenser tube, a thermometer, and a stirrer, and 1.68 g (0.015 mol) of 3 compounds (potassium-tert-butoxide) and 20 ml of tetrahydrofuran (hereinafter THF) were added. Stir while introducing nitrogen.

  1 compound: 3.01 g (0.0105 mol), 2 compound: 2.91 g (0.005 mol) dissolved in 20 ml of THF, and slowly added dropwise to the above compound 3 / THF mixture while keeping the internal temperature at 45 ° C. or lower. To do. After completion of the dropping, the reaction is carried out for 5 hours while maintaining the internal temperature of 45 to 50 ° C.

  Attach a stirrer to a 200 ml beaker, add 20 ml of methanol and stir. After pouring the reaction solution after the above-mentioned reaction for 5 hours, 20 ml of water is further poured, and the mixture is stirred for about 30 minutes and filtered. The crystals collected by filtration are washed with about 40 ml of methanol / water = 1/1 and dried overnight in a drying box at 50-60 ° C. Crude crystals: 3.8 g was obtained. This crude crystal was purified with a column to obtain 3.2 g of Compound Example T-2.

  Synthesis Example (2); Synthesis of Compound T-24

  A 100 ml four-headed flask was equipped with a nitrogen inlet tube, a condenser tube, a thermometer, and a stirrer, and 1.68 g (0.015 mol) of 3 compounds (potassium-tert-butoxide) and 20 ml of tetrahydrofuran (hereinafter THF) were added. Stir while introducing nitrogen.

  1 compound: 3.31 g (0.0105 mol), 2 compound: 2.91 g (0.005 mol) dissolved in 20 ml of THF, and slowly dropped into the above compound 3 / THF mixture while keeping the internal temperature at 45 ° C. or lower. To do. After completion of the dropping, the reaction is carried out for 5 hours while maintaining the internal temperature of 45 to 50 ° C.

  Attach a stirrer to a 200 ml beaker, add 20 ml of methanol and stir. After pouring the reaction solution after the above-mentioned reaction for 5 hours, 20 ml of water is further poured, and the mixture is stirred for about 30 minutes and filtered. The crystals collected by filtration are washed with about 40 ml of methanol / water = 1/1 and dried overnight in a drying box at 50-60 ° C. Crude crystals: 4.13 g was obtained. This crude crystal was purified with a column to obtain 3.04 g of Compound Example T-24.

  Synthesis Example (3); Synthesis of Compound T-50

  A 100 ml four-headed flask was equipped with a nitrogen inlet tube, a condenser tube, a thermometer, and a stirrer, and 1.68 g (0.015 mol) of 3 compounds (potassium-tert-butoxide) and 20 ml of tetrahydrofuran (hereinafter THF) were added. Stir while introducing nitrogen.

  1 compound: 3.31 g (0.0105 mol), 2 compound: 3.12 g (0.005 mol) was dissolved in 20 ml of THF and slowly dropped into the above compound 3 / THF mixture while keeping the internal temperature at 45 ° C. or lower. To do. After completion of the dropping, the reaction is carried out for 5 hours while maintaining the internal temperature of 45 to 50 ° C.

  Attach a stirrer to a 200 ml beaker, add 20 ml of methanol and stir. After pouring the reaction solution after the above-mentioned reaction for 5 hours, 20 ml of water is further poured, and the mixture is stirred for about 30 minutes and filtered. The crystals collected by filtration are washed with about 40 ml of methanol / water = 1/1 and dried overnight in a drying box at 50-60 ° C. Crude crystals: 4.30 g was obtained. This crude crystal was purified with a column to obtain 3.05 g of Compound Example T-50.

  Next, the layer structure of an electrophotographic photoreceptor using the organic compound of the present invention as a charge transport material, particularly an organic photoreceptor, will be described.

  The organic photoconductor of the present invention means an electrophotographic photoconductor constituted by giving an organic compound at least one of a charge generation function and a charge transport function indispensable for the constitution of the electrophotographic photoconductor. It contains all known organic electrophotographic photoreceptors such as a photoreceptor composed of an organic charge generating material or an organic charge transport material, a photoreceptor composed of a polymer complex with a charge generating function and a charge transport function.

  The constitution of the organic photoreceptor used in the present invention is described below.

Conductive Support The conductive support used for the photoreceptor may be either a sheet or a cylinder, but a cylindrical conductive support is preferred for designing an image forming apparatus compactly. .

  Cylindrical conductive support means a cylindrical support necessary for forming an endless image by rotating. Conductivity is within a range of 0.1 mm or less in straightness and 0.1 mm or less in deflection. A support is preferred. Exceeding the range of straightness and shake makes it difficult to form a good image.

As the conductive material, a metal drum such as aluminum or nickel, a plastic drum deposited with aluminum, tin oxide, indium oxide or the like, or a paper / plastic drum coated with a conductive substance can be used. The conductive support preferably has a specific resistance of 10 ³ Ωcm or less at room temperature.

  As the conductive support used in the present invention, one having an alumite film that has been sealed on the surface thereof may be used. The alumite treatment is usually performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid, etc., but anodizing treatment in sulfuric acid gives the most preferable result. In the case of anodizing treatment in sulfuric acid, the sulfuric acid concentration is preferably 100 to 200 g / L, the aluminum ion concentration is 1 to 10 g / L, the liquid temperature is about 20 ° C., and the applied voltage is preferably about 20 V. It is not limited. The average film thickness of the anodized film is usually 20 μm or less, particularly preferably 10 μm or less.

Intermediate layer In the present invention, an intermediate layer having a barrier function may be provided between the conductive support and the photosensitive layer.

  In the present invention, in order to improve the adhesion between the conductive support and the photosensitive layer, or to prevent charge injection from the support, an intermediate layer (including an undercoat layer) is provided between the support and the photosensitive layer. Including) can also be provided. Examples of the material for the intermediate layer include polyamide resins, vinyl chloride resins, vinyl acetate resins, and copolymer resins containing two or more of these resin repeating units. Of these subbing resins, a polyamide resin is preferable as a resin capable of reducing the increase in residual potential due to repeated use. The film thickness of the intermediate layer using these resins is preferably 0.01 to 0.5 μm.

  Examples of the intermediate layer preferably used in the present invention include an intermediate layer using a curable metal resin obtained by thermosetting an organic metal compound such as a silane coupling agent or a titanium coupling agent. As for the film thickness of the intermediate | middle layer using curable metal resin, 0.1-2 micrometers is preferable.

  An intermediate layer preferably used in the present invention includes an intermediate layer in which inorganic particles are dispersed in a binder resin. The average particle diameter of the inorganic particles is preferably 0.01 to 1 μm. In particular, an intermediate layer in which N-type semiconductive fine particles subjected to surface treatment are dispersed in a binder is preferable. For example, an intermediate layer in which titanium oxide having an average particle size of 0.01 to 1 μm, which has been surface-treated with silica / alumina treatment and a silane compound, is dispersed in a polyamide resin. The film thickness of such an intermediate layer is preferably 1 to 20 μm.

  The N-type semiconducting fine particles are fine particles having the property of using conductive carriers as electrons. That is, the property that the conductive carrier is an electron is that the N-type semiconducting fine particles are contained in an insulating binder to effectively block hole injection from the substrate, and to convert electrons from the photosensitive layer into electrons. On the other hand, it has the property which does not show blocking property.

  Here, a method for discriminating N-type semiconductor particles will be described.

  An intermediate layer having a thickness of 5 μm is formed on the conductive support (the intermediate layer is formed using a dispersion in which 50% by mass of particles are dispersed in the binder resin constituting the intermediate layer). The intermediate layer is negatively charged and the light attenuation characteristics are evaluated. In addition, the light attenuation characteristics are similarly evaluated by charging to positive polarity.

  N-type semiconductive particles are particles that are dispersed in the intermediate layer in the above evaluation when the light attenuation when charged negatively is greater than the light attenuation when charged positively. It is called semiconductive particle.

Specific examples of the N-type semiconducting fine particles include fine particles of titanium oxide (TiO ₂ ), zinc oxide (ZnO), tin oxide (SnO ₂ ), etc. In the present invention, titanium oxide is particularly preferably used. It is done.

  The average particle diameter of the N-type semiconducting fine particles used in the present invention is preferably in the range of 10 nm to 500 nm in the number average primary particle diameter, more preferably 10 nm to 200 nm, and particularly preferably 15 nm to 50 nm. .

  The intermediate layer using N-type semiconducting fine particles whose number average primary particle size is within the above range can be finely dispersed in the layer, has sufficient potential stability, and generates black spots. Has a prevention function.

  For example, in the case of titanium oxide, the number-average primary particle size of the N-type semiconducting fine particles is magnified 10,000 times by observation with a transmission electron microscope, and 100 particles are randomly observed as primary particles. It is measured as the number average diameter.

  The shape of the N-type semiconducting fine particles used in the present invention includes dendritic, needle-like, and granular shapes. For example, in the case of titanium oxide particles, the N-type semiconductive fine particles have a crystalline form. There are anatase type, rutile type and amorphous type, but any crystal type may be used, or two or more crystal types may be mixed and used. Of these, the rutile type is the best.

  One of the hydrophobizing surface treatments performed on the N-type semiconducting fine particles is a plurality of surface treatments, and the last surface treatment is a surface treatment with a reactive organosilicon compound. Is to do. In addition, at least one of the surface treatments is at least one surface treatment selected from alumina, silica, and zirconia, and finally the surface treatment of the reactive organosilicon compound is performed. It is preferable.

  Alumina treatment, silica treatment, and zirconia treatment are treatments for depositing alumina, silica, or zirconia on the surface of the N-type semiconducting fine particles. Alumina, silica, and zirconia deposited on these surfaces include alumina, silica, Zirconia hydrates are also included. The surface treatment of the reactive organosilicon compound means using a reactive organosilicon compound in the treatment liquid.

  In this way, the surface treatment of the N-type semiconductive fine particles such as titanium oxide particles was performed at least twice, so that the surface of the N-type semiconductive fine particles was uniformly coated (treated), and the surface treatment was performed. When N-type semiconducting fine particles are used in the intermediate layer, a good photoconductor having good dispersibility of N-type semiconductive fine particles such as titanium oxide particles in the intermediate layer and causing no image defects such as black spots. You can get it.

Photosensitive layer The photosensitive layer configuration of the photoreceptor of the present invention may be a single-layer photosensitive layer configuration in which the intermediate layer has a charge generation function and a charge transport function in one layer, but more preferably the function of the photosensitive layer. The charge generation layer (CGL) and the charge transport layer (CTL) may be separated from each other. By adopting a configuration in which the functions are separated, an increase in the residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negatively charged photoconductor, it is preferable that a charge generation layer (CGL) is formed on the intermediate layer and a charge transport layer (CTL) is formed thereon. In the positively charged photoconductor, the order of the layer configuration is the reverse of that in the negatively charged photoconductor. The most preferred photosensitive layer structure of the present invention is a negatively charged photoreceptor structure having the function separation structure.

  The structure of the photosensitive layer of the function-separated negatively charged photoreceptor will be described below.

Charge generation layer The charge generation layer contains a charge generation material (CGM). Other substances may contain a binder resin and other additives as necessary.

  A known charge generation material (CGM) can be used as the charge generation material (CGM). For example, a phthalocyanine pigment, an azo pigment, a perylene pigment, an azulenium pigment, or the like can be used. Among these, CGM which can minimize the increase in residual potential due to repeated use has a crystal structure capable of taking a stable aggregate structure among a plurality of molecules, specifically, a phthalocyanine pigment having a specific crystal structure, CGM of a perylene pigment is mentioned. For example, CGMs such as titanyl phthalocyanine having a maximum peak at a Bragg angle 2θ of 27.2 ° with respect to Cu—Kα rays and benzimidazole perylene having a maximum peak at 2θ of 12.4 have little deterioration due to repeated use. Potential increase can be reduced.

  When a binder is used as the CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferred resins include formal resin, butyral resin, silicone resin, silicone-modified butyral resin, phenoxy resin, and the like. Can be mentioned. The ratio of the binder resin to the charge generating material is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential associated with repeated use can be minimized. The thickness of the charge generation layer is preferably 0.01 μm to 2 μm.

Charge Transport Layer The charge transport layer contains a charge transport material (CTM) and a binder resin that forms a film by dispersing CTM. Other substances may contain additives such as antioxidants as necessary.

  As the charge transport material (CTM), the compound of the general formula (1) is used. In addition to the compound of the general formula (1), for example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound, and the like can be used in combination. These charge transport materials are usually dissolved in a suitable binder resin to form a layer.

  Examples of the resin used for the charge transport layer (CTL) include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, and polycarbonate. Resin, silicone resin, melamine resin, and copolymer resin containing two or more of repeating unit structures of these resins. In addition to these insulating resins, high molecular organic semiconductors such as poly-N-vinylcarbazole can be used.

  Most preferred as a binder for these CTLs is a polycarbonate resin. The polycarbonate resin is most preferable in improving the dispersibility and electrophotographic characteristics of CTM. The ratio of the binder resin to the charge transport material is preferably 10 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

  The charge transport layer preferably contains an antioxidant. Typical examples of the antioxidants prevent the action of oxygen on auto-oxidizing substances existing in the electrophotographic photosensitive member or on the surface of the electrophotographic photosensitive member under conditions of light, heat, and discharge. It is also a substance having a suppressing property. Typical examples include the following compound groups.

  The charge transport layer may be composed of two or more layers. In this case, the charge transport layer on the surface may satisfy the configuration of the present invention. The thickness of the charge transport layer is preferably 10 to 40 μm.

  In the above, the most preferable layer structure of the photoreceptor of the present invention is exemplified, but in the present invention, a photoreceptor layer structure other than the above may be used.

  As a solvent or dispersion medium used for forming a layer such as a photosensitive layer, an intermediate layer, and a surface layer, n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone, methyl ethyl ketone , Methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethane , Tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosolve, etc. And the like. Although this invention is not limited to these, Dichloromethane, 1, 2- dichloroethane, methyl ethyl ketone, etc. are used preferably. These solvents may be used alone or as a mixed solvent of two or more.

  Further, the coating solution for each layer is preferably filtered with a metal filter, a membrane filter or the like in order to remove foreign matters and aggregates in the coating solution before entering the coating step. For example, it is preferable to select a pleat type (HDC), a depth type (profile), a semi-depth type (profile star), etc., manufactured by Nippon Pole Co., Ltd. according to the characteristics of the coating solution and perform filtration.

  Next, as a coating processing method for producing the organic electrophotographic photosensitive member, a coating processing method such as dip coating, spray coating, circular amount regulation type coating, etc. is used. In order to prevent the film from being dissolved as much as possible, and in order to achieve uniform coating processing, it is preferable to use a coating processing method such as spray coating or circular amount regulation type (circular slide hopper type is a typical example). It is most preferable to use the circular amount regulation type coating method for the protective layer. The circular amount regulation type coating is described in detail in, for example, Japanese Patent Application Laid-Open No. 58-189061.

  Next, an image forming method and an image forming apparatus using the electrophotographic photosensitive member of the present invention will be described.

  FIG. 1 is a cross-sectional configuration diagram of an image forming apparatus as an example of the image forming method of the present invention.

  In FIG. 1, reference numeral 50 denotes a photosensitive drum (photosensitive member) which is an image bearing member, which is a photosensitive member coated with an organic photosensitive layer on the drum, and is grounded and rotated clockwise. Reference numeral 52 denotes a scorotron charger (charging means) for uniformly charging the circumferential surface of the photosensitive drum 50 by corona discharge. Prior to the charging by the charger 52, the peripheral surface of the photosensitive member may be discharged by performing exposure by the pre-charging exposure unit 51 using a light emitting diode or the like in order to eliminate the history of the photosensitive member in the previous image formation.

  After uniform charging of the photoreceptor, image exposure based on the image signal is performed by an image exposure unit 53 as image exposure means. The image exposure unit 53 in this figure uses a laser diode (not shown) as an exposure light source. Scanning on the photosensitive drum is performed by the light whose optical path is bent by the reflection mirror 532 through the rotating polygon mirror 531 and the fθ lens, and an electrostatic latent image is formed.

  Here, the reversal development process means that the surface of the photoreceptor is uniformly charged by the charger 52, and the exposed area of the photoreceptor, that is, the exposed area potential (exposed area) of the photoreceptor is developed by the developing process (means). This is an image forming method for visualizing. On the other hand, the unexposed portion potential is not developed by the developing bias potential applied to the developing sleeve 541.

The electrostatic latent image is then developed by a developing device 54 as developing means. A developing device 54 containing a developer composed of toner and carrier is provided on the periphery of the photosensitive drum 50, and development is performed by a developing sleeve 541 that contains a magnet and rotates while holding the developer. The inside of the developing device 54 is composed of developer agitating / conveying members 544 and 543, a conveying amount regulating member 542, and the like, and the developer is agitated and conveyed and supplied to the developing sleeve. Controlled by member 542. The developer transport amount varies depending on the linear velocity and developer specific gravity of the applied electrophotographic photosensitive member, but is generally in the range of ^{20 to} 200 mg / cm ² .

  The developer is, for example, a carrier composed of the above-mentioned ferrite as a core and coated with an insulating resin around it, and a coloring material such as carbon black, a charge control agent, and a low molecular weight polyolefin mainly composed of the above-mentioned styrene acrylic resin. The toner is composed of a toner in which silica, titanium oxide, or the like is externally added to the particles. The developer is transported to the development area with the layer thickness regulated by a transport amount regulating member, and development is performed. At this time, usually, development is performed by applying a DC bias between the photosensitive drum 50 and the developing sleeve 541 and, if necessary, an AC bias voltage. Further, the developer is developed in contact with or not in contact with the photoreceptor. The potential of the photosensitive member is measured by providing a potential sensor 547 above the development position as shown in FIG.

  The recording paper P is fed to the transfer area by the rotation operation of the paper feed roller 57 when the transfer timing is ready after the image formation.

  In the transfer area, a transfer electrode (transfer means: transfer device) 58 is operated on the peripheral surface of the photosensitive drum 50 in synchronization with the transfer timing, and the charged recording paper P is charged with a polarity opposite to that of the toner. Transfer the toner.

  Next, the recording paper P is neutralized by a separation electrode (separator) 59, separated by the peripheral surface of the photosensitive drum 50 and conveyed to the fixing device 60, and the toner is removed by heating and pressurization of the heat roller 601 and the pressure roller 602. After the welding, the sheet is discharged to the outside of the apparatus via the sheet discharge roller 61. The transfer electrode 58 and the separation electrode 59 stop the primary operation after passing through the recording paper P, and prepare for the next toner image formation. In FIG. 1, a transfer band electrode of corotron is used as the transfer electrode 58. The transfer electrode setting conditions vary depending on the process speed (peripheral speed) of the photosensitive member and cannot be specified. For example, the transfer current is set to +100 to +400 μA, and the transfer voltage is set to +500 to +2000 V. can do.

  On the other hand, after the recording paper P has been separated, the photosensitive drum 50 removes and cleans residual toner by the pressure contact of the blade 621 of the cleaning device (cleaning means) 62, and again removes the charge by the pre-charge exposure unit 51 and charges by the charger 52. Then, the next image forming process is started.

  Reference numeral 70 denotes a detachable process cartridge in which a photoconductor, a charger, a transfer device, a separator, and a cleaning device are integrated.

  The electrophotographic photosensitive member of the present invention is generally applicable to electrophotographic apparatuses such as an electrophotographic copying machine, a laser printer, an LED printer, and a liquid crystal shutter printer, and further displays, recordings, light printing, plate making and the like using electrophotographic technology. It can be widely applied to apparatuses such as facsimiles.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. However, “part” in the following text indicates “part by mass”.

A photoreceptor was prepared as follows.
Preparation of photoconductor 1 <intermediate layer>
Polyamide resin (Amilan CM-8000: manufactured by Toray Industries, Inc.) 60 parts Inorganic fine particles: Titanium oxide SMT500SAS (manufactured by Teica; surface treatment is silica treatment, alumina treatment, and methylhydrogenpolysiloxane treatment) 180 parts Methanol 1600 parts 1- Butanol 400 parts The above components were mixed and dissolved to prepare an intermediate layer coating solution. This coating solution was applied onto a cylindrical aluminum substrate by a dip coating method, and after drying, an intermediate layer having a thickness of 1.0 μm was formed.
<Charge generation layer>
Titanyl phthalocyanine pigment (pigment with Cu-Kα characteristic X-ray diffraction spectrum and maximum peak of Bragg angle 2θ of 27.3 °) 60 parts Silicone resin solution (KR5240, 15% xylene-butanol solution: Shin-Etsu Chemical Co., Ltd.) 700 parts 2-butanone 2000 parts The above components were mixed and dispersed for 10 hours using a sand mill to prepare a charge generation layer coating solution. This coating solution was applied onto the intermediate layer by a dip coating method, and after drying, a charge generation layer having a thickness of 0.3 μm was formed.
<Charge transport layer>
Charge transport material (Compound of Synthesis Example (1): T-2) 150 parts Binder resin: Bisphenol Z-type polycarbonate (Iupilon Z300: manufactured by Mitsubishi Gas Chemical Company) 300 parts Antioxidant (Sanol LS2626: Sankyo Company) 7 parts Tetrahydrofuran 1100 parts Toluene 1100 parts The above components were mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer by a dip coating method and dried at 125 ° C. for 50 minutes to form a charge transport layer having a thickness of 22 μm.

Preparation of photoconductors 2 to 13 Photoconductors 2 to 13 were prepared in the same manner as in photoconductor 1 except that the charge generation material, the compound of the charge transport material, the amount of the compound, and the thickness of the charge transport layer were changed as shown in Table 1. Was made.

Production of photoconductor 14 (comparative example)
A photoconductor 14 was produced in the same manner as in the photoconductor 1, except that the charge transport material was changed from the compound of Synthesis Example (1) to the following compound A.

In the table, Y is a titanyl phthalocyanine pigment (a pigment having a maximum peak at a Bragg angle 2θ of 27.3 ° in a Cu-Kα characteristic X-ray diffraction spectrum).
Z represents a benzimidazole perylene pigment (a pigment having a maximum peak at a Bragg angle 2θ of 12.4 ° in a Cu-Kα characteristic X-ray diffraction spectrum).

Evaluation Each of the photoconductors 1 to 14 obtained as described above has a reversal development type digital copying machine “Konica 7085” (Scorotron charger, semiconductor laser image exposure device (wavelength 680 nm), and reversal development means manufactured by Konica Corporation. The following evaluation items were evaluated. Evaluation was performed by changing environmental conditions (temperature and humidity conditions) for each evaluation item. The evaluation basically consists of an original image in which the character ratio, halftone image, solid white image, and solid black image with a pixel rate of 7% are divided into ¼ equal parts in A4 and 10,000 sheets in intermittent mode. A copy was made and evaluated. The evaluation results are shown in Table 2.

Evaluation condition Line speed: 420 mm / second Time to reach from the image exposure to the development position; 0.108 seconds Charging condition Charger; Scorotron charger (negative charge)
Charging potential: -700V to -750V
Exposure condition Set to the exposure amount that makes the solid black image portion potential -100V.

Exposure beam; Laser uses a 680 nm semiconductor laser. Development conditions The developer is a carrier coated with an insulating resin with ferrite as the core, and a styrene acrylic resin as the main materials. Colorant of carbon black, charge control agent, and low molecular weight polyolefin. A toner developer in which silica and titanium oxide were externally added to colored particles having a volume average particle size of 5.3 μm produced by a polymerization method comprising:

Transfer conditions Transfer pole; corona charging method (positive charging)
Separation conditions Cleaning conditions using the separation means of the separation claw unit A cleaning blade having a hardness of 70 °, a rebound resilience of 65%, a thickness of 2 (mm), and a free length of 9 mm is applied to the cleaning portion at a linear pressure of 18 (g / cm) in the counter direction. It contact | abutted by the weight load system so that it might become.

Evaluation item and evaluation method High-speed response under low-temperature and low-humidity (10 ° C, 20% RH) environment (potential change in solid black image area)
In a low-temperature, low-humidity (10 ° C, 20% RH) environment, one A4 original image with a pixel rate of 7%, a halftone image, a solid white image, and a solid black image each divided into 1/4 equal intervals In this mode, 10,000 sheets were copied, and the potential change (| ΔV |) of the solid black image portion at the development position after the initial and 10,000 sheets was evaluated. The smaller | ΔV |, the better the high-speed response in a low-temperature, low-humidity (10 ° C, 20% RH) environment.

A: Potential change in solid black image portion | ΔV | is less than 50 V (good)
○: Potential change of solid black image portion | ΔV | is 50 V to 150 V (no problem in practical use)
×: The potential change | ΔV | of the solid black image portion is larger than 150 V (practically problematic)
Character thinning (under low temperature and low humidity (10 ° C, 20% RH))
An original image on which a line image having a width of 0.1 mm and 0.2 mm was printed was copied and evaluated.

◎; The reproduced image is reproduced with a line width of 75% or more of the line width of the original image (good)
○: The line width of the copied image is reproduced at 40% to 74% of the line width of the original image (a level that causes no problem in practice).
×: The line width of the copied image is 39% or less of the line width of the original image, or the line width is cut (a level causing a problem in practice).
Black spot (high temperature and high humidity (30 ℃ 80% RH))
The occurrence of black spots (spot-like spot images) on the halftone image was determined according to the following criteria.

A: No black spot nuclei were observed on the photoreceptor, and no black spots were generated even in halftone images (good).
○: Black spot nuclei are seen on the photoreceptor, but no black spots are generated in the halftone image (no problem in practical use)
X: Nuclei of black spots are observed on the photosensitive member, and black spots are also generated in the halftone image (there is a practical problem)
Periodic image defects (high temperature and high humidity (30 ° C, 80% RH))
The periodicity coincided with the period of the photoconductor, and the number of visible white defects, black spots, and streak image defects per A4 size was determined.

A: Frequency of image defects of 0.4 mm or more: All copy images are 5 / A4 or less (good)
○: Frequency of image defects of 0.4 mm or more: 1 or more of 6 / A4 or more and 10 / A4 or less (no problem in practical use)
X: Frequency of image defects of 0.4 mm or more: 11 or more A4 or more occurred (practical problem)
Crack In the environment of 30 ° C. and 80% RH, the digital copying machine Konica 7085 was turned off with the power supply turned off and left for 2 days. The members around the photoconductor are in a state in which the operation is only stopped during this period, that is, the members such as the cleaning blade and the developer conveying member are kept in contact with the photoconductor. Thereafter, the surface of the photoreceptor was observed to observe the presence or absence of cracks. Moreover, image evaluation was also performed, and the presence or absence of generation of streak-like image defects due to the occurrence of cracks was also evaluated.

A: Evaluating 100 photoconductors, no cracks or streak-like image defects (good)
◯: 100 photoconductors were evaluated, fine cracks were generated, but no streak-like image defects were generated (a level of no problem in practical use).
X: 100 photoconductors were evaluated, and cracks and streak-like image defects were observed (practically problematic level)
Image density (low temperature and low humidity (10 ° C, 20% RH))
The image density of the solid black part was measured by reflection density using RD-918 manufactured by Macbeth. Evaluation was made by relative density (the density of A4 paper not copied is 0.00).

◎; 1.2 or more (good)
○: Less than 1.2 to 0.8 (a level with no practical problem)
×: Less than 0.8 (a level that causes practical problems)
Sharpness The sharpness of the image was evaluated by squashing characters by displaying images in both low temperature and low humidity (10 ° C., 20% RH) and high temperature, high humidity (30 ° C., 80% RH) environments. 3-point and 5-point character images were formed and evaluated according to the following criteria.

◎; 3 points and 5 points are clear and easy to read ○; 3 points are partially illegible, 5 points are clear and easily readable ×: 3 points are almost unreadable and 5 points are one Part or whole is illegible

  From Table 2, the photoreceptors 1 to 13 using the compound of the general formula (1) of the present invention as a charge transport material have high-speed response (low solid black image area) in a low temperature and low humidity (10 ° C., 20% RH) environment. (Potential change) is excellent, and therefore, there is no character thinning under low temperature and low humidity, and there are no occurrences of black spots, periodic image defects, cracks, etc., and excellent image density and sharpness are exhibited. On the other hand, the photoconductor 14 using a compound other than the present invention as a charge transport material deteriorates high-speed response (change in potential of a solid black image portion) in a low-temperature and low-humidity (10 ° C., 20% RH) environment. Thinning and sharpness have deteriorated.

1 is a cross-sectional configuration diagram of an image forming apparatus as an example of an image forming method of the present invention.

Explanation of symbols

50 Photosensitive drum (photosensitive member)
DESCRIPTION OF SYMBOLS 51 Pre-charge exposure part 52 Charging device 53 Image exposure device 54 Development device 541 Development sleeve 543, 544 Developer stirring conveyance member 547 Potential sensor 57 Paper feed roller 58 Transfer electrode 59 Separation electrode (separator)
60 Fixing device 61 Paper discharge roller 62 Cleaning device 70 Process cartridge

Claims (6)

An organic compound represented by the following general formula (1):

In general formula (1), R _{1 to} R ₁₁ represent a hydrogen atom, a substituted or unsubstituted alkyl group, an alkoxy group or a halogen atom, and Ar _{1 to} Ar ₄ represent a substituted or unsubstituted aryl group or an aralkyl group. . However, Ar ₁ and Ar ₂ , Ar ₃ and Ar ₄ may be bonded to each other to form a ring. k, l and m each represent an integer of 1 to 4, and n represents an integer of 1 or more. An electrophotographic photoreceptor comprising the organic compound represented by the general formula (1). An electrophotographic photosensitive member comprising a charge generation layer and a charge transport layer on a conductive support, wherein the charge transport layer contains the organic compound represented by the general formula (1). Electrophotographic photosensitive member containing the organic compound of the general formula (1), charging means for uniformly charging the electrophotographic photosensitive member, and latent image formation for forming an electrostatic latent image on the charged electrophotographic photosensitive member Developing means for developing an electrostatic latent image on the electrophotographic photosensitive member; transfer means for transferring a toner image visualized on the electrophotographic photosensitive member onto a transfer material; At least one of a charge eliminating means for removing the charge on the photographic photosensitive member and a cleaning means for removing the toner remaining on the electrophotographic photosensitive member after transfer is integrally supported, and is detachably attached to the image forming apparatus main body. A process cartridge that can be attached to a cartridge. An image forming apparatus comprising the process cartridge according to claim 4. An image forming method comprising forming an electrophotographic image using the image forming apparatus according to claim 5.

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