Electrophotographic apparatus and process cartridge

Abstract

To provide an excellent electrophotographic apparatus that maintains high image quality from the initial stage through to the end of its lifespan, by using a developing roller containing urethane rubber in its elastic layer, thereby suppressing image defects (density unevenness) after endurance under high temperature and high humidity conditions. [Solution] An electrophotographic apparatus characterized in that the electrophotographic photoreceptor has a surface layer containing a binder resin, the surface layer contains polyester resin as the binder resin, the polyester resin has structural units represented by formula (1) and structural units represented by formula (2), and the developing roller has an elastic layer, the elastic layer contains urethane rubber. JPEG2026067312000135.jpg49150

Description

[Technical Field]

[0001] The present invention relates to an electrophotographic photoreceptor, an electrophotographic apparatus using a developing roller, and a process cartridge. [Background technology]

[0002] In recent years, there has been a growing demand for electrophotographic equipment with longer lifespan and higher image quality, and there is a need for equipment that maintains high image quality stability even after repeated use (after durability has been achieved).

[0003] Organic electrophotographic photoreceptors containing organic photoconductive materials (charge-generating materials) (hereinafter also simply referred to as "electrophotographic photoreceptors" or "photoreceptors") are used as electrophotographic photoreceptors mounted in electrophotographic devices and process cartridges. In recent years, in addition to addressing the need for longer lifespan as described above, electrophotographic devices are required to improve image quality by suppressing image defects even after repeated use (end of durability) in high-temperature and high-humidity environments, thereby maintaining high image quality from the initial use through to the end of durability.

[0004] On the other hand, developing rollers containing urethane rubber in the elastic layer are sometimes used to maintain high image quality from the initial stage through to the end of its lifespan, and also for cost reduction purposes. However, it is known that urethane rubber deteriorates due to hydrolysis when exposed to high temperature and humidity for extended periods, and image defects (density unevenness) caused by the deterioration of urethane rubber may occur (Patent Documents 1 and 3).

[0005] For example, Patent Document 2 proposes a developing roller using urethane rubber obtained by reacting a polyol with a polyisocyanate. Also, Patent Document 3 proposes a developing roller containing ether-based urethane rubber. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 10-48942 [Patent Document 2] Japanese Patent Publication No. 2019-74717 [Patent Document 3] Japanese Patent Publication No. 2016-99516 [Overview of the project] [Problems that the invention aims to solve]

[0007] According to our research, in image forming apparatuses using developing rollers described in Patent Documents 1 and 2, the image quality deteriorates after endurance under high temperature and high humidity conditions, in order to suppress image defects, and there is room for improvement.

[0008] Therefore, the object of the present invention is to provide an excellent electrophotographic apparatus that uses a developing roller containing urethane rubber in its elastic layer, which suppresses image defects (density unevenness) after durability under high temperature and high humidity conditions, and maintains high image quality from the initial stage through to the end of durability. [Means for solving the problem]

[0009] The above objective is achieved by the present invention as follows: That is, the electrophotographic apparatus according to the present invention is Electrophotographic photoreceptor, and A contact developing means comprising toner and a developing roller, for developing an electrostatic latent image formed on the surface of an electrophotographic photoreceptor by bringing the developing roller, on which the toner is carried, into contact with the electrophotographic photoreceptor. An electrophotographic apparatus having The electrophotographic photoreceptor has a surface layer containing a binder resin, The surface layer contains polyester resin as the binder resin, The polyester resin has structural units represented by the following formula (1) and structural units represented by the following formula (2), The developing roller has an elastic layer, The elastic layer is characterized by containing urethane rubber.

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[0012] Furthermore, the process cartridge according to the present invention is Electrophotographic photoreceptor, and A contact developing means comprising toner and a developing roller, for developing an electrostatic latent image formed on the surface of an electrophotographic photoreceptor by bringing the developing roller, on which the toner is carried, into contact with the electrophotographic photoreceptor. A process cartridge characterized by integrally supporting the main body of an electrophotographic apparatus and being detachable from the main body of the electrophotographic apparatus, The electrophotographic photoreceptor has a surface layer containing a binder resin, The surface layer contains polyester resin as the binder resin, The polyester resin has structural units represented by the following formula (1) and structural units represented by the following formula (2), The developing roller has an elastic layer, The elastic layer is characterized by containing urethane rubber.

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[0015] According to the present invention, an electrophotographic apparatus using a developing roller containing urethane rubber in its elastic layer can be provided that suppresses image defects (density unevenness) after endurance under high temperature and high humidity conditions, and maintains high image quality from the initial stage through to the endurance stage. [Brief explanation of the drawing]

[0016] [Figure 1] This figure shows an example of the layer structure of an electrophotographic photoreceptor in the present invention. [Figure 2] This figure shows an example of the layer structure of an electrophotographic photoreceptor in the present invention. [Figure 3] This figure shows an example of the layer structure of an electrophotographic photoreceptor in the present invention. [Figure 4] This figure shows an example of the layer structure of an electrophotographic photoreceptor in the present invention. [Figure 5] This figure shows an example of the layer structure of an electrophotographic photoreceptor in the present invention. [Figure 6] This figure shows an example of the layer structure of an electrophotographic photoreceptor in the present invention. [Figure 7] This figure shows an example of the configuration of the developing roller in the present invention. [Figure 8] This figure shows an example of a schematic configuration of an electrophotographic apparatus having an electrophotographic photoreceptor according to the present invention. [Modes for carrying out the invention]

[0017] The present invention will be described in detail below with reference to preferred embodiments.

[0018] In image forming apparatuses using developing rollers containing urethane rubber in the elastic layer described in Patent Documents 1 and 2, it was found that image defects (density unevenness) occur when durability testing is performed under high temperature and high humidity conditions.

[0019] From this, it is thought that even in developing rollers that contain urethane rubber in the elastic layer, which is intended to suppress the deterioration of urethane rubber, the urethane rubber in the developing roller undergoes hydrolysis due to long-term use under high temperature and high humidity conditions. As a result, the hardness of the elastic layer is thought to become uneven at a microscopic level. This is thought to cause uneven pressure during toner development on the electrophotographic photoreceptor, resulting in areas where the amount of toner on the electrophotographic photoreceptor differs from the desired amount, and consequently causing image defects (density unevenness).

[0020] Based on the above assumptions, we investigated various means to maintain high image quality from the initial stage to after durability, while suppressing image defects (density unevenness) after durability under high temperature and high humidity conditions in an electrophotographic apparatus using a developing roller containing urethane rubber in the elastic layer. As a result, we arrived at the configuration of the present invention.

[0021] The electrophotographic apparatus according to the present invention is Electrophotographic photoreceptor, and An electrophotographic apparatus having toner and a developing roller, and a contact developing means for developing an electrostatic latent image formed on the surface of an electrophotographic photoreceptor by bringing the developing roller, on which the toner is carried, into contact with the electrophotographic photoreceptor, The electrophotographic photoreceptor has a surface layer containing a binder resin, The surface layer contains polyester resin as the binder resin, The polyester resin has structural units represented by the following formula (1) and structural units represented by the following formula (2), The developing roller has an elastic layer, The elastic layer contains urethane rubber. This is an electrophotographic apparatus characterized by the following features.

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[0024] In the present invention, the developing roller is a developing roller having a shaft and an elastic layer provided on the outer circumference of the shaft, wherein the elastic layer contains urethane rubber.

[0025] Furthermore, the electrophotographic photoreceptor has a surface layer containing a binder resin, and the surface layer contains a polyester resin having structural units represented by formula (1) and formula (2) as the binder resin. As a result, it has been found that image defects (density unevenness) after endurance under high temperature and high humidity conditions are suppressed, and high image quality can be maintained from the initial stage through to the endurance stage.

[0026] Polyester resins having the structural units shown in formula (1) and formula (2) are presumed to have an ether structure, which provides flexibility to the resin structure and facilitates the formation of a uniform film. Electrophotographic photoreceptors containing this resin have a more uniform film, and therefore, the pressure applied when toner is developed from the developing roller is thought to be transmitted more uniformly. When the developing roller and the urethane rubber in the elastic layer are exposed to high temperature and high humidity for a long period, hydrolysis is thought to occur. Due to the microscopic, locally occurring defects in the urethane rubber resulting from hydrolysis, the pressure applied to the toner when developing it from the developing roller onto the surface of the electrophotographic photoreceptor is thought to be uneven. By containing this resin, the electrophotographic photoreceptor relatively evens out the pressure unevenness of the developing roller, thereby reducing image defects after durability under high temperature and high humidity conditions.

[0027] [Electrophotographic photoconductor] The electrophotographic photoreceptor of the present invention comprises at least a support and a photosensitive layer formed on the support. Examples include a single-layer electrophotographic photoreceptor (hereinafter sometimes referred to as a single-layer photoreceptor) and a positively charged multilayer electrophotographic photoreceptor (hereinafter sometimes referred to as a positively charged multilayer photoreceptor).

[0028] One method for manufacturing the electrophotographic photoreceptor of the present invention is to prepare coating solutions for each layer, as described later, apply them in the desired order, and then dry them. Methods for applying the coating solutions include immersion coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, and ring coating. Among these, immersion coating is preferred from the viewpoint of efficiency and productivity.

[0029] The details are explained below.

[0030] (Single-layer photoreceptor) The following describes a single-layer photoreceptor, which is an example of a photoreceptor in this embodiment, with reference to Figures 1 to 3. Figures 1 to 3 each show a partial cross-sectional view of a single-layer photoreceptor. As shown in Figure 1, the single-layer photoreceptor 1 comprises, for example, a conductive support 2 and a photosensitive layer 3. The photosensitive layer 3 of the single-layer photoreceptor 1 is a single layer (1 layer). The single-layer photosensitive layer 3 is the first photosensitive layer, a single-layer photosensitive layer 3s. As shown in Figure 2, the single-layer photoreceptor 1 may further include an undercoat layer 4 (intermediate layer) in addition to the conductive support 2 and the single-layer photosensitive layer 3s. The undercoat layer 4 is provided between the conductive support 2 and the single-layer photosensitive layer 3s. As shown in Figure 1, the single-layer photosensitive layer 3s may be provided directly on the conductive support 2. Alternatively, as shown in Figure 2, the single-layer photosensitive layer 3s may be provided on the conductive support 2 via an undercoat layer 4. As shown in Figure 3, the single-layer photoreceptor 1 may further include a protective layer 5 in addition to the conductive support 2 and the single-layer photosensitive layer 3s. The protective layer 5 is provided on the single-layer photosensitive layer 3s. As shown in Figures 1 and 2, it is preferable that the single-layer photosensitive layer 3s is provided as the outermost layer of the single-layer photoreceptor 1. Providing the single-layer photosensitive layer 3s containing the polyester resin (PAR), which will be described later, as the outermost layer makes it easier to suppress the decrease in transfer efficiency after durability. As shown in Figure 3, the protective layer 5 may also be provided as the outermost layer of the single-layer photoreceptor 1. The thickness of the single-layer photosensitive layer 3s is not particularly limited, but is preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 50 μm or less. The first photosensitive layer, the single-layer photosensitive layer 3s, contains a charge generating material, a binder resin, an electron transport material, and a hole transport material.

[0031] (Positively charged stacked photoreceptor) The following describes a positively charged multilayer photoreceptor 10, an example of a photoreceptor according to the first embodiment, with reference to Figures 4 to 6. Figures 4 to 6 each show a partial cross-sectional view of the positively charged multilayer photoreceptor 10. As shown in Figure 4, the positively charged multilayer photoreceptor 10 comprises, for example, a conductive substrate 2 and a photosensitive layer 3. The photosensitive layer 3 of the positively charged multilayer photoreceptor 10 consists of two layers. The two photosensitive layers 3 are a charge generation layer 12 and a charge transport layer 11. The charge generation layer 12 is the first photosensitive layer. The charge transport layer 11 is the second photosensitive layer. The charge generation layer 12, which is the first photosensitive layer, is provided on the outermost surface of the two photosensitive layers 3 (charge generation layer 12 and charge transport layer 11). The charge transport layer 11 is provided closer to the conductive substrate 2 than the charge generation layer 12. Since the charge generation layer 12 is located on the outermost surface (opposite the side of the positively charged multilayer photoreceptor 10 where the conductive substrate 2 is provided), for example, the charge transport layer 11 is provided on the conductive substrate 2, and the charge generation layer 12 is provided on the charge transport layer 11. When the positively charged multilayer photoreceptor 10 is provided in an image forming apparatus, the positively charged multilayer photoreceptor 10 is charged to a positive polarity by a charging device. As shown in Figure 5, the positively charged multilayer photoreceptor 10 may further include an intermediate layer 4 (undercoat layer) in addition to the conductive substrate 2 and the photosensitive layer 3. The intermediate layer 4 is provided between the conductive substrate 2 and the photosensitive layer 3 (for example, the charge transport layer 11). As shown in Figure 4, the photosensitive layer 3 (for example, the charge transport layer 11) may be provided directly on the conductive substrate 2. Alternatively, as shown in Figure 5, the photosensitive layer 3 (for example, the charge transport layer 11) may be provided on the conductive substrate 2 via the intermediate layer 4. As shown in Figure 6, the positively charged multilayer photoreceptor 10 may further include a protective layer 5 in addition to the conductive substrate 2 and the photosensitive layer 3. The protective layer 5 is provided on the photosensitive layer 3 (for example, the charge generation layer 12). As shown in Figures 4 and 5, it is preferable that the photosensitive layer 3 is provided as the outermost layer of the positively charged multilayer photoreceptor 10. Providing the photosensitive layer 3 (for example, the charge generation layer 12) containing a polyarylate resin (PA) and a specific electron transport agent, as described later, as the outermost layer makes it easier to improve the fogging resistance of the positively charged multilayer photoreceptor 10. Note that, as shown in Figure 6, the protective layer 5 may also be provided as the outermost layer of the positively charged multilayer photoreceptor 10.

[0032] <Support> In the present invention, the electrophotographic photoreceptor has a support. In the present invention, the support is preferably a conductive support. The shape of the support can be cylindrical, belt-shaped, or sheet-shaped. Among these, a cylindrical support is preferred. Furthermore, the surface of the support may be subjected to electrochemical treatments such as anodizing, blasting, or cutting.

[0033] Suitable materials for the support include metal, resin, and glass.

[0034] Examples of metals include aluminum, iron, nickel, copper, gold, stainless steel, and alloys thereof. Among these, an aluminum support made of aluminum is preferred.

[0035] Furthermore, conductivity may be imparted to resins and glass by processes such as mixing or coating them with conductive materials.

[0036] <Underlayer> In the present invention, an undercoat layer may be provided on the support. By providing an undercoat layer, the interlayer adhesion function is enhanced and a charge injection prevention function can be provided.

[0037] The undercoat layer preferably contains a resin. Alternatively, the undercoat layer may be formed as a cured film by polymerizing a composition containing a monomer having polymerizable functional groups.

[0038] Examples of resins include polyester resin, polyarylate resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, epoxy resin, melamine resin, polyurethane resin, phenolic resin, polyvinylphenol resin, alkyd resin, polyvinyl alcohol resin, polyethylene oxide resin, polypropylene oxide resin, polyamide resin, polyamic acid resin, polyimide resin, polyamide-imide resin, and cellulose resin.

[0039] Polymerizable functional groups found in monomers possessing polymerizable functional groups include isocyanate groups, blocked isocyanate groups, methylol groups, alkylated methylol groups, epoxy groups, metal alkoxide groups, hydroxyl groups, amino groups, carboxyl groups, thiol groups, carboxylic acid anhydride groups, and carbon-carbon double bond groups.

[0040] Furthermore, the undercoat layer may further contain electron transport materials, metal oxides, metals, conductive polymers, etc., for the purpose of improving electrical properties. Among these, electron transport materials and metal oxides are preferred.

[0041] Examples of electron transport materials include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadienylidene compounds, fluorenone compounds, xanthone compounds, benzophenone compounds, cyanovinyl compounds, aryl halides, silole compounds, and boron-containing compounds. An electron transport material having polymerizable functional groups may be used as the electron transport material, and a base layer may be formed as a cured film by copolymerizing it with the above-mentioned monomers having polymerizable functional groups.

[0042] Examples of metal oxides include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, and silicon dioxide. Examples of metals include gold, silver, and aluminum.

[0043] Furthermore, the underlayer may contain additional additives.

[0044] The average thickness of the undercoat layer is preferably 0.1 μm or more and 50 μm or less, more preferably 0.2 μm or more and 40 μm or less, and particularly preferably 0.3 μm or more and 30 μm or less.

[0045] The undercoat can be formed by preparing an undercoat coating solution containing the above-mentioned materials and solvents, forming a coating film, and then drying and / or curing it. Examples of solvents used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0046] <Single-layer photosensitive layer> In the present invention, a single-layer photosensitive layer is provided on a support, or on an undercoat layer provided on the support.

[0047] The single-layer photosensitive layer in the present invention comprises at least a binder resin, a charge generating material, a hole transport material, and an electron transport material.

[0048] [Binding resin] The binder resin used in the photosensitive layer contains a polyester resin having structural units represented by formula (1) and structural units represented by formula (2).

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[0051] The structural unit represented by formula (1) is a highly electron-accepting structure. Furthermore, when combined with the structural unit represented by formula (2), resonance stabilization occurs, further increasing electron-acceptance. An electrophotographic photoreceptor containing a polyester resin having the structural units represented by formula (1) and formula (2) is thought to assist the positive charge of the toner when the positively charged toner is developed on the electrophotographic photoreceptor and transferred to the transfer material. As a result, the electrophotographic photoreceptor becomes relatively negatively charged, relatively increasing the positive charge of the toner and reducing the amount of toner left over after transfer.

[0052] The polyester resin may also contain, in addition to the structural units represented by formula (1) and formula (2), the structural units represented by formula (4) and formula (5) below.

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[0055] By including the structural units represented by formula (4) and the structural units represented by formula (5), the solubility of the polyester resin in solvents is improved, and a photosensitive layer can be formed well.

[0056] In the polyester resin, let M1 be the amount of substance of the structural unit represented by formula (1), and M4 be the amount of substance of the structural unit represented by formula (4). The ratio of M1 to the total amount of substance of M1 and M4, M1 / (M1+M4), is preferably greater than 0.30 from the viewpoint of suppressing a decrease in transfer efficiency. More preferably, M1 / (M1+M4) is 0.55 or greater.

[0057] In the above-mentioned polyester resin, when the amount of substance of the structural unit represented by formula (1) is M1 and the amount of substance of the structural unit represented by formula (4) is M4, with respect to the total amount of substance MC of the dicarboxylic acid-derived structural units constituting the polyester resin, it is preferable that (M1 + M4) / MC is 0.50 or more.

[0058] In the above-mentioned polyester resin, when MC is the total amount of substance of the dicarboxylic acid-derived structural units constituting the polyester resin, and M1 is the amount of substance of the structural unit represented by formula (1), it is preferable that M1 / MC ≥ 0.50 is satisfied.

[0059] In the polyester resin, let the amount of substance of the structural unit represented by the formula (2) be M2, and the amount of substance of the structural unit represented by the formula (5) be M5. And the ratio of M2 to the total amount of substance of M2 and M5, M2 / (M2+M5), is preferably greater than 0 from the viewpoint of suppressing the decrease in transfer efficiency. On the other hand, M2 / (M2+M5) is preferably 0.50 or less from the viewpoint of solubility in the solvent. That is, it is preferable that M2 / (M2+M5) satisfies 0<M2 / (M2+M5)≦0.50. By improving the solubility in the solvent, the photosensitive layer can be formed well.

[0060] In the polyester resin, let the amount of substance of the structural unit represented by the formula (1) be M1, and the amount of substance of the structural unit represented by the formula (4) be M4. And the ratio of M4 to the total amount of substance of M1 and M4, M4 / (M1+M4), preferably satisfies 0.30≦M4 / (M1+M4)≦0.70 in terms of solubility in the solvent.

[0061] In the polyester resin, let the amount of substance of the structural unit represented by the formula (2) be M2, and the amount of substance of the structural unit represented by the formula (5) be M5. And the ratio of M5 to the total amount of substance of M2 and M5, M5 / (M2+M5), is preferably less than 0.70 from the viewpoint of suppressing the decrease in transfer efficiency. Also, M5 / (M2+M5) is preferably 0.50 or more from the viewpoint of solubility in the solvent.

[0062] In the above polyester resin, when the total amount of substance of the structural units derived from bisphenol constituting the polyester resin is MB, and the amount of substance of the structural unit represented by the formula (2) is M2 and the amount of substance of the structural unit represented by the formula (5) is M5, it is preferable that (M2+M5) / MB is 0.5 or more.

[0063] The photosensitive layer may contain a resin other than the above polyester resin as long as the effects of the present invention are not impaired. Examples of other resins include polycarbonate resins, styrene resins, acrylic resins, etc. The polyarylate resin may be, for example, a random copolymer, an alternating copolymer, a periodic copolymer, or a block copolymer.

[0064] The viscosity-average molecular weight of the polyester resin (PAR) is preferably 10,000 or more, more preferably 30,000 or more, and even more preferably 50,000 or more. When the viscosity-average molecular weight of the polyester resin (PAR) is 10,000 or more, the abrasion resistance of the photoreceptor is improved. On the other hand, the viscosity-average molecular weight of the polyester resin (PAR) is preferably 80,000 or less, and more preferably 70,000 or less. When the viscosity-average molecular weight of the polyester resin (PAR) is 80,000 or less, the polyester resin (PAR) dissolves easily in the solvent for forming the photosensitive layer.

[0065] In the present invention, the polyester resin is composed of a structural unit represented by formula (2) as a bisphenol-derived repeating unit, and a structural unit represented by formula (1) as a dicarboxylic acid-derived repeating unit. Furthermore, in the present invention, it is preferable that the polyester resin is further composed of a structural unit represented by formula (5) as a bisphenol-derived repeating unit, and a structural unit represented by formula (4) as a dicarboxylic acid-derived repeating unit. Examples of bisphenols for constituting the bisphenol-derived repeating unit include the compound represented by formula (BP-2) and the compound represented by formula (BP-5) (hereinafter sometimes referred to as compound (BP-2) and compound (BP-5), respectively). Examples of dicarboxylic acids for constituting the dicarboxylic acid-derived repeating unit include the compound represented by formula (DC-1) and the compound represented by formula (DC-4) (hereinafter sometimes referred to as compound (DC-1) and compound (DC-4)), respectively. The bisphenol ratio in the resin (i.e., the content ratio of structural units represented by formula (2) and formula (5)) can be adjusted by changing the amounts of compound (BP-2) and compound (BP-5) added during the production of polyester resin (PAR). Similarly, the dicarboxylic acid ratio in the resin (i.e., the content ratio of structural units represented by formula (1) and formula (4)) can be adjusted by changing the amounts of compound (DC-1) and compound (DC-4) added during production.

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[0070] Bisphenols (e.g., compounds (BP-2) and (BP-5)) may be used after derivatization to aromatic diacetates. Dicarboxylic acids (e.g., compounds (DC-1) and (DC-4)) may be used after derivatization. Examples of dicarboxylic acid derivatives include dicarboxylic acid dichlorides, dicarboxylic acid dimethyl esters, dicarboxylic acid diethyl esters, and dicarboxylic acid anhydrides. Dicarboxylic acid dichlorides are compounds in which the two "-C(=O)-OH" groups of a dicarboxylic acid are each replaced with "-C(=O)-Cl" groups.

[0071] In the condensation polymerization of bisphenol and dicarboxylic acid, one or both of a base and / or a catalyst may be added. Examples of bases include sodium hydroxide. Examples of catalysts include benzyltributylammonium chloride, ammonium chloride, ammonium bromide, quaternary ammonium salts, triethylamine, and trimethylamine.

[0072] The photosensitive layer may contain only polyester resin (PAR) having structural units represented by formula (1) and formula (2) as the binder resin, or it may further contain other binder resins (hereinafter sometimes referred to as other binder resins contained in the photosensitive layer). Other binder resins contained in the photosensitive layer include, for example, thermoplastic resins (more specifically, polyester resins other than the polyester resin (PAR) in the present invention, polycarbonate resins, styrene-based resins, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers, styrene-acrylic acid copolymers, acrylic copolymers, polyethylene resins, ethylene-vinyl acetate copolymers, chlorinated polyethylene resins, polyvinyl chloride resins, polypropylene resins, ionomers, vinyl chloride-vinyl acetate copolymers, polyester resins, alkyd resins, polyamide resins, polyurethane resins, polysulfone resins, diallyl phthalate resins, ketone resins, polyvinyl butyral resins, polyvinyl acetal resins, and polyether resins), thermosetting resins (more specifically, silicone resins, epoxy resins, phenolic resins, urea resins, melamine resins, and other crosslinkable thermosetting resins), and photocurable resins (more specifically, epoxy-acrylic acid resins and urethane-acrylic acid copolymers). The binder resin contained in the photosensitive layer preferably contains 50% by mass or more of a polyester resin having structural units represented by formula (1) and structural units represented by formula (2), relative to the total mass of the binder resin.

[0073] [Charge-generating material] Examples of charge-generating materials include phthalocyanine pigments, perylene pigments, bisazo pigments, trisazo pigments, dithioketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metallic naphthalocyanine pigments, squaline pigments, indigo pigments, azulenium pigments, cyanine pigments, powders of inorganic photoconductive materials (e.g., selenium, selenium-tellurium, selenium-arsenide, cadmium sulfide, and amorphous silicon), pyryllium pigments, ancencelon pigments, triphenylmethane pigments, surene pigments, toluidine pigments, pyrazoline pigments, and quinacridone pigments. The photosensitive layer may contain only one type of charge-generating material, or it may contain two or more types of charge-generating materials.

[0074] Phthalocyanine pigments are pigments having a phthalocyanine structure. Examples of phthalocyanine pigments include metal-free phthalocyanines and metal phthalocyanines. Examples of metal phthalocyanines include titanyl phthalocyanine, hydroxygallium phthalocyanine, and chlorogallium phthalocyanine. Titanyl phthalocyanine is preferred as the metal phthalocyanine. Titanyl phthalocyanine is a compound represented by the following formula (CGM-1), and metal-free phthalocyanines are compounds represented by the following formula (CGM-2).

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[0077] Phthalocyanine pigments may be crystalline or amorphous. Examples of metal-free phthalocyanine crystals include X-type crystals of metal-free phthalocyanine (hereinafter sometimes referred to as X-type metal-free phthalocyanine). Examples of titanyl phthalocyanine crystals include α-type, β-type, and Y-type crystals of titanyl phthalocyanine (hereinafter sometimes referred to as α-type titanyl phthalocyanine, β-type titanyl phthalocyanine, and Y-type titanyl phthalocyanine, respectively). For example, in digital optical electrophotographic devices (for example, laser beam printers or facsimiles using a light source such as a semiconductor laser), it is preferable to use a photoreceptor that is sensitive to wavelengths of 700 nm or more. Because they have a high quantum yield in the wavelength range of 700 nm or more, phthalocyanine pigments are preferred as charge generating materials, metal-free phthalocyanine or titanyl phthalocyanine is more preferred, and titanyl phthalocyanine is even more preferred. Among these, Y-type titanyl phthalocyanine is particularly preferred.

[0078] Y-type titanyl phthalocyanine has a major peak at, for example, 27.2° of the Bragg angle (2θ±0.2°) in its CuKα-characterized X-ray diffraction spectrum. The major peak in a CuKα-characterized X-ray diffraction spectrum is the peak with the first or second highest intensity in the range where the Bragg angle (2θ±0.2°) is between 3° and 40°. Y-type titanyl phthalocyanine does not have a peak at 26.2° in its CuKα-characterized X-ray diffraction spectrum.

[0079] The CuKα characteristic X-ray diffraction spectrum can be measured, for example, by the following method. First, the sample is placed in the sample holder of an X-ray diffractometer (for example, RIGAK Corporation's "RINT(registered trademark) 1100"), and the X-ray diffraction spectrum is measured under the following conditions: Cu X-ray tube, tube voltage 40kV, tube current 30mA, and CuKα characteristic X-ray wavelength 1.542Å. The measurement range (2θ) is, for example, 3° to 40° (start angle 3°, stop angle 40°), and the scanning speed is, for example, 10° / min. The main peak is determined from the obtained X-ray diffraction spectrum, and the Bragg angle of the main peak is read.

[0080] The charge-generating substance content is preferably 0.1 parts by mass or more and 50 parts by mass or less, and more preferably 0.5 parts by mass or more and 5 parts by mass or less, per 100 parts by mass of the binder resin.

[0081] [Electron transport material] The electron transport material may include at least one selected from the group consisting of the compound represented by formula (10), the compound represented by formula (11), the compound represented by formula (12), the compound represented by formula (13), the compound represented by formula (14), the compound represented by formula (15), and the compound represented by formula (16). Including the above electron transport material in the photosensitive layer is thought to enhance the effects of the present invention by increasing the compatibility between the binder resin and the hole transport material described later, thereby improving the homogeneity inside the photosensitive layer.

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[0088]

Chem.

[0089] Q in formula (10) 1 and Q 2 、Q in formula (11) 11 、Q 12 、and Q 13 、Q in formula (12) 21 、Q 22 、Q 23 、and Q 24 、Q in formula (13) 31 and Q 32 、Q in formula (14) 41 、Q 42 、Q 43 、and Q 44 、Q in formula (15) 51 、Q 52 、Q 53 、Q 54 、Q 55 、and Q 56 、and Q in formula (16) 61 and Q 62 each independently represents an aryl group having 6 to 14 carbon atoms which may be substituted with at least one substituent selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms and a halogen atom. Y in formula (15) 1 and Y 2 each independently represents an oxygen atom or a sulfur atom.

[0090] Q in formula (10) 1 and Q 2 、Q in formula (11) 11 ~Q 13 、Q in formula (12) 21 ~Q 24 、Q in formula (13) 31 and Q 32 、Q in formula (14) 41 ~Q 44 、Q in formula (15) 51 ~Q 56, and Q in equation (16) 61 and Q 62 Preferably, each of these independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 14 carbon atoms which may be substituted with at least one substituent selected from the group consisting of an alkyl group having 1 to 6 carbon atoms and a halogen atom. 1 and Y 2 It is preferable that this represents an oxygen atom.

[0091] Q in equation (10) 1 and Q 2 Q in equation (11) 11 ~Q 13 Q in equation (12) 21 ~Q 24 Q in equation (13) 31 and Q 32 Q in equation (14) 41 ~Q 44 Q in equation (15) 51 ~Q 56 , and Q in equation (16) 61 and Q 62 When each represents an alkyl group having 1 to 6 carbon atoms, it is preferable that each represents an alkyl group having 1 to 5 carbon atoms, and it is preferable that each represents a methyl group, an ethyl group, a propyl group, a butyl group, or a pentyl group, and it is particularly preferable that each represents a methyl group, an isopropyl group, a tert-butyl group, or a 1,1-dimethylpropyl group.

[0092] Q in equation (10) 1 and Q 2 Q in equation (11) 11 ~Q 13 Q in equation (12) 21 ~Q 24 Q in equation (13) 31 and Q 32 Q in equation (14) 41 ~Q 44 Q in equation (15) 51 ~Q 56 , and Q in equation (16) 61 and Q 62When each represents an aryl group having 6 to 14 carbon atoms, it is preferable that it represents an aryl group having 6 to 10 carbon atoms, and more preferably a phenyl group. The aryl group having 6 to 14 carbon atoms may be substituted with at least one substituent selected from the group consisting of alkyl groups having 1 to 6 carbon atoms and halogen atoms. As the alkyl group having 1 to 6 carbon atoms as a substituent, an alkyl group having 1 to 3 carbon atoms is preferred, and a methyl group or an ethyl group is more preferred. As the halogen atom as a substituent, a fluorine atom, a chlorine atom, or a bromine atom is preferred, and a chlorine atom is particularly preferred. When the aryl group having 6 to 14 carbon atoms is substituted with a substituent, the number of substituents is preferably 1 to 5, and more preferably 1 or 2. As the aryl group having 6 to 14 carbon atoms substituted with at least one substituent selected from the group consisting of alkyl groups having 1 to 6 carbon atoms and halogen atoms, a chlorophenyl group, a dichlorophenyl group, or an ethylmethylphenyl group is preferred, and a 4-chlorophenyl group, a 2,5-dichlorophenyl group, or a 2-ethyl-6-methylphenyl group is more preferred.

[0093] A preferred example of the compound represented by formula (10) is the compound represented by formula (E-4). A preferred example of the compound represented by formula (11) is the compound represented by formula (E-5). A preferred example of the compound represented by formula (12) is the compound represented by formula (E-7). A preferred example of the compound represented by formula (13) is the compound represented by formula (E-6). A preferred example of the compound represented by formula (14) is the compound represented by formula (E-8). A preferred example of the compound represented by formula (15) is the compound represented by formula (E-2) and the compound represented by formula (E-3). A preferred example of the compound represented by formula (16) is the compound represented by formula (E-1). Hereinafter, the compounds represented by formulas (E-1) to (E-8) may be referred to as electron transport materials (E-1) to (E-8), respectively.

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[0102] The content of the electron transport material is preferably 5 parts by mass or more and 150 parts by mass or less, more preferably 10 parts by mass or more and 100 parts by mass or less, and even more preferably 30 parts by mass or more and 70 parts by mass or less, per 100 parts by mass of the binder resin. The photosensitive layer may contain only one type of electron transport material, or it may contain two or more types of electron transport materials.

[0103] [Hole transport material] As hole transporting materials, the compounds represented by formula (20), formula (21), formula (22), formula (23), and formula (24) below, when included in the photosensitive layer, are thought to enhance the effects of the present invention by increasing the compatibility between the binder resin and the electron transporting material and improving the homogeneity inside the photosensitive layer.

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[0109] In formula (20), R 11 , R 12 , R 13 , and R 14 Each independently represents an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. a1, a2, a3, and a4 each independently represent an integer between 0 and 5. In formula (20), when a1 represents an integer between 2 and 5, multiple R 11 These may represent the same base or different bases. When a2 represents an integer between 2 and 5, multiple R 12 These may represent the same base or different bases. When a3 represents an integer between 2 and 5, multiple R 13may represent the same group as each other or different groups. When a4 represents an integer of 2 or more and 5 or less, a plurality of Rs 14 may represent the same group as each other or different groups. In formula (20), R 11 , R 12 , R 13 , and R 14 preferably each independently represents an alkyl group having 1 to 3 carbon atoms, more preferably represents a methyl group or an ethyl group. a1, a2, a3, and a4 preferably each independently represent an integer of 1 or more and 3 or less, and more preferably represent 1.

[0110] In formula (21), R 21 , R 22 , and R 23 each independently represents an alkyl group having 1 to 6 carbon atoms. R 24 , R 25 , and R 26 each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. b1, b2, and b3 each independently represent 0 or 1. In formula (21), R 21 , R 22 , and R 23 preferably each independently represents an alkyl group having 1 to 3 carbon atoms, more preferably represents a methyl group. The bonding positions of R 21 , R 22 , and R 23 in the phenyl group are preferably the meta position with respect to the bonding position with the triphenylamine structure of the phenyl group. R 24 , R 25 , and 26 preferably each represents a hydrogen atom. b1, b2, and b3 preferably all represent 0 or all represent 1.

[0111] In formula (22), R 31 , R 32 , and R 33 each independently represents an alkyl group having 1 to 6 carbon atoms. R 34represents an alkyl group or hydrogen atom having 1 to 6 carbon atoms. d1, d2, and d3 each independently represent an integer between 0 and 5. In formula (22), when d1 represents an integer between 2 and 5, multiple R 31 These may represent the same base or different bases. When d2 represents an integer between 2 and 5, multiple R 32 These may represent the same base or different bases. When d3 represents an integer between 2 and 5, multiple R 33 These may represent the same group or different groups. In equation (22), R 34 It is preferable that represents a hydrogen atom. It is preferable that d1, d2, and d3 each represent 0.

[0112] In formula (23), R 41 , R 42 , R 43 , R 44 , R 45 , and R 46 Each of these independently represents an alkyl group having 1 to 6 carbon atoms, or a phenyl group. 47 and R 48 Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group. Each independently represents an integer between 0 and 5. Each independently represents an integer between 0 and 4. Each independently represents an integer between 0 and 4. Each independently represents 0 or 1. In formula (23), when e1 represents an integer between 2 and 5, multiple R 41 These may represent the same base or different bases. When e2 represents an integer between 2 and 5, multiple R 42 These may represent the same base or different bases. When e3 represents an integer between 2 and 5, multiple R 43 These may represent the same base or different bases. When e4 represents an integer between 2 and 5, multiple R 44 These may represent the same base or different bases. When e5 represents an integer between 2 and 4, multiple R 45These may represent the same base or different bases. When e6 represents an integer between 2 and 4, multiple R 46 These may represent the same group or different groups. In equation (23), R 41 ~R 46 Each of these groups preferably independently represents an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and even more preferably a methyl group or an ethyl group. 47 and R 48 e1, e2, e3, and e4 each preferably represent an integer between 0 and 2, with e1 and e2 representing 0 and e3 and e4 representing 2. e5 and e6 preferably represent 0. e7 and e8 preferably both represent 0 or both represent 1.

[0113] In formula (24), R 50 and R 51 Each of these independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group. 52 , R 53 , R 54 , R 55 , R 56 , R 57 , and R 58 Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms. Each independently represents an integer between 0 and 2. Each independently represents an integer between 0 and 5. In formula (24), when f3 represents an integer between 2 and 5, multiple R 50 These may represent the same base or different bases. When f4 represents an integer between 2 and 5, multiple R 51 These may represent the same group or different groups. In equation (24), R 50 and R 51 Preferably, each of these independently represents an alkyl group having 1 to 6 carbon atoms. 52 and R53 Each of these preferably represents a phenyl group which may be substituted with a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. 54 ~R 58 Each of these preferably independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. It is preferable that f1 and f2 both represent 0, both represent 1, or both represent 2. It is preferable that f3 and f4 each independently represent 0 or 1. 50 and R 51 When each represents an alkyl group having 1 to 6 carbon atoms, it is preferable that each represents an alkyl group having 1 to 3 carbon atoms, and more preferably that each represents a methyl group. 52 and R 53 When each represents a phenyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms, it is preferable to represent a phenyl group or a phenyl group substituted with an alkyl group having 1 to 3 carbon atoms. A methylphenyl group is preferred as the phenyl group substituted with an alkyl group having 1 to 3 carbon atoms, and a 4-methylphenyl group is more preferred. 54 ~R 58 When each represents an alkyl group having 1 to 6 carbon atoms, it is preferable that each represents an alkyl group having 1 to 4 carbon atoms, and it is preferable that each represents a methyl group, an ethyl group, or an n-butyl group. 54 ~R 58 When each represents an alkoxy group having 1 to 6 carbon atoms, it is preferable that each represents an alkoxy group having 1 to 3 carbon atoms, and more preferably that each represents an ethoxy group.

[0114] A preferred example of the compound represented by formula (20) is the compound represented by formula (H-11). A preferred example of the compound represented by formula (21) is the compound represented by formula (H-7) and the compound represented by (H-8). A preferred example of the compound represented by formula (22) is the compound represented by formula (H-6). A preferred example of the compound represented by formula (23) is the compound represented by formula (H-9) and the compound represented by (H-10). A preferred example of the compound represented by formula (24) is the compound represented by formula (H-1), the compound represented by formula (H-2), the compound represented by formula (H-3), the compound represented by formula (H-4), and the compound represented by formula (H-5). Hereinafter, the compounds represented by formulas (H-1) to (H-11) may be referred to as hole transporters (H-1) to (H-11), respectively.

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[0126] The hole transporter content is preferably 10 to 200 parts by mass, more preferably 30 to 120 parts by mass, and even more preferably 50 to 90 parts by mass, per 100 parts by mass of the binder resin. The photosensitive layer may contain only one type of hole transporter, or it may contain two or more types of hole transporters. Furthermore, the photosensitive layer may further contain hole transporters other than the compounds represented by formulas (20), (21), (22), (23), or (24) (hereinafter sometimes referred to as other hole transporters). Other hole transporters include, for example, triphenylamine derivatives, diamine derivatives (e.g., N,N,N',N'-tetraphenylbenzidine derivatives, N,N,N',N'-tetraphenylphenylenediamine derivatives, N,N,N',N'-tetraphenylnaphthylenediamine derivatives, N,N,N',N'-tetraphenylphenantolylenediamine derivatives, and di(aminophenylethenyl)benzene derivatives), oxadiazole compounds (e.g., 2,5-di(4-methylaminophenyl)-1,3,4-oxadiazoles), and oxadiazole compounds (e.g., 2,5-di(4-methylaminophenyl)-1,3,4-oxadiazoles). Examples include diazoles, styryl compounds (e.g., 9-(4-diethylaminostyryl)anthracene), carbazole compounds (e.g., polyvinylcarbazole), organic polysilane compounds, pyrazoline compounds (e.g., 1-phenyl-3-(p-dimethylaminophenyl)pyrazoline), hydrazone compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, and triazole compounds.

[0127] [Additives] The photosensitive layer may contain additives as needed. Examples of additives include ultraviolet absorbers, antioxidants, radical scavengers, singlet quenchers, softeners, surface modifiers, bulking agents, thickening agents, waxes, donors, surfactants, plasticizers, sensitizers, and leveling agents. In particular, it is preferable to add a small amount of the compound represented by the following formula (30) (hereinafter also referred to as compound (T-1)).

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[0129] (Vickers hardness) The Vickers hardness of the photosensitive layer is preferably 18.0 HV or higher, and more preferably 19.0 HV or higher. When the Vickers hardness of the photosensitive layer is 19.0 HV or higher, the uniformity of the photoreceptor film is improved, and the effect of smoothing out pressure unevenness is greatly enhanced. There is no particular upper limit to the Vickers hardness of the photosensitive layer, but for example, it is 25.0 HV or lower. If it is too high, it may actually increase pressure unevenness. The Vickers hardness of the photosensitive layer is measured by a method conforming to JIS (Japanese Industrial Standards) Z2244. The Vickers hardness of the photosensitive layer can be adjusted, for example, by changing the type of binder resin, hole transporter, and electron transporter.

[0130] [developing roller] [Axis] As shown in Figure 7, the developing roller 21 of the present invention includes a shaft 22. The material constituting the shaft 22 is not particularly limited as long as it has good conductivity. For example, it can be a shaft made of metal, a shaft made of a high-rigidity resin substrate, or a combination thereof, or it may be a cylindrical body made of metal or high-rigidity resin with the inside hollowed out.

[0131] When using a high-rigidity resin for the shaft 22, it is preferable to add and disperse a conductive agent in the high-rigidity resin to ensure sufficient conductivity. Here, preferred conductive agents to be dispersed in the high-rigidity resin are powdered conductive agents such as carbon black powder, graphite powder, carbon fiber, metal powders such as aluminum, copper, and nickel, metal oxide powders such as tin oxide, titanium oxide, and zinc oxide, and conductive glass powder. These conductive agents may be used individually or in combination of two or more. The amount of conductive agent is not particularly limited, but it is preferably in the range of 5 to 40% by mass, and more preferably in the range of 5 to 20% by mass, relative to the total amount of the high-rigidity resin.

[0132] Examples of the material for the metal shaft body or the metal cylindrical body include iron, stainless steel, aluminum, etc., and those coated with zinc or nickel may also be used. Examples of the material for the high-rigidity resin base material include polyacetal, polyamide 6, polyamide 6·6, polyamide 12, polyamide 4·6, polyamide 6·10, polyamide 6·12, polyamide 11, polyamide MXD6, polybutylene terephthalate, polyphenylene oxide, polyphenylene sulfide, polyether sulfone, polycarbonate, polyimide, polyamideimide, polyetherimide, polysulfone, polyetheretherketone, polyethylene terephthalate, polyarylate, liquid crystal polymer, polytetrafluoroethylene, polypropylene, ABS resin, polystyrene, polyethylene, melamine resin, phenol resin, silicone resin, etc. Among these, polyacetal, polyamide 6·6, polyamide MXD6, polyamide 6·12, polybutylene terephthalate, polyphenylene ether, polyphenylene sulfide, and polycarbonate are preferable. These high-rigidity resins may be used alone or in combination of two or more kinds.

[0133] [Elastic layer] In the developing roller 21 of the present invention, as shown in the figure, it is preferable to have an elastic layer 23 outside the shaft body 22. There is no particular limitation on this elastic layer 23, and it can have the same configuration as the elastic layer of a known conductive roller.

[0134] Examples of the material constituting the elastic layer 23 can be formed of, for example, an elastomer or a resin, or a foam (foam) of these. Also, an elastomer obtained by blending an electron conductive agent such as carbon black or an ion conductive agent such as sodium perchlorate into an elastomer alone or its foam, or an elastomer which is a UV-curable resin material and contains an ion conductive agent can be used. In any case, an elastomer containing a polymer having a urethane skeleton and a conductive agent is preferable.

[0135] Examples of elastomers include silicone rubber, urethane rubber, polybutadiene rubber, polyisoprene rubber, natural rubber, styrene-butadiene rubber, nitrile rubber, ethylene propylene rubber, acrylic rubber, epichlorohydrin rubber, chloroprene rubber, and mixtures thereof. These elastomers can also be used as foams by chemically foaming them with a foaming agent, or by mechanically foaming them by enclosing air, as is the case with polyurethane foams.

[0136] Among elastomers alone or foams obtained by foaming them, it is preferable to use polyurethane foam obtained from a polyurethane raw material containing a polyol component and an isocyanate component. This polyurethane foam will be described below.

[0137] There are no particular restrictions on the polyol component; known polyols used as raw materials for urethane foam production can be used. Polyether polyols, polyester polyols, polyester polyether polyols, etc., can be appropriately selected depending on the application of the roller, but polyester polyols and polyether polyols are particularly preferred, and either one or both of these can be used in mixture form.

[0138] More specifically, examples of polyether polyols include polyether polyols obtained by addition polymerization of glycerin with alkylene oxides such as polyethylene oxide or propylene oxide, polyether polyols obtained by ring-opening polymerization of tetrahydrofuran, and polyether polyols such as polytetramethylene glycol, ethylene glycol, propanediol, and butanediol.

[0139] Examples of polyester polyols include condensation-type polyester polyols obtained by condensation of dicarboxylic acids with diols or triols, lactone-based polyester polyols obtained by ring-opening polymerization of lactones based on diols or triols, and ester-modified polyols obtained by esterifying the ends of polyether polyols with lactones.

[0140] These polyols are not particularly limited, but their number-average molecular weight is preferably 360 to 8,000, and especially preferably 500 to 5,600. Furthermore, the number of functional groups is preferably 2.0 to 3.

[0141] Examples of isocyanate components include tolylene diisocyanate (TDI), prepolymerized tolylene diisocyanate (prepolymerized TDI), diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate (crude MDI), isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, and hexamethylene diisocyanate (HDI); as well as isocyanurate-modified, carbodiimide-modified, and glycol-modified versions thereof. These may be used individually or in combination of two or more. Among the above, isophorone diisocyanate and tolylene diisocyanate are preferred.

[0142] The isocyanate may be prepolymerized with a polyol beforehand. One method for this is to incubate the isocyanate and polyol at a temperature of 40 to 70°C, preferably for 6 to 240 hours, and more preferably for 24 to 72 hours. In this case, the ratio of polyol to isocyanate is preferably adjusted so that the isocyanate content of the resulting prepolymer is 4 to 30% by mass, and more preferably 6 to 15% by mass. If the isocyanate content is less than 4% by mass, the stability of the prepolymer will be impaired, and the prepolymer may harden during storage, making it unusable. Furthermore, if the isocyanate content exceeds 30% by mass, the content of unprepolymerized isocyanate increases, and this isocyanate hardens with the polyol component used in the subsequent polyurethane curing reaction through a reaction mechanism similar to that of a one-shot method that does not undergo a prepolymerization reaction, thus reducing the effectiveness of using the prepolymerization method. When using an isocyanate component that has been prepolymerized with a polyol, the polyol component can be, in addition to the polyol components described later, diols such as ethylene glycol and butanediol, polyols such as trimethylolpropane and sorbitol, or their derivatives.

[0143] Polyol components may include polyether polyols, polyester polyols, polybutadiene polyols, hydrogenated polybutadiene polyols, alkylene oxide-modified polybutadiene polyols, and polyisoprene polyols. Polyether polyols can be obtained by addition polymerization of ethylene oxide or propylene oxide with a polyhydric alcohol or polyhydric amine under a basic catalyst. Examples of polyhydric alcohols and amines include propylene glycol, ethylene glycol, glycerin, trimethylolpropane, triethanolamine, pentaerythritol, ethylenediamine, aromatic diamine, diethylenetriamine, sorbitol, and sucrose.

[0144] Polyester polyols are obtained by dehydrating and condensing a carboxylic acid and a polyhydric alcohol. Examples of carboxylic acids include adipic acid and phthalic acid, while examples of polyhydric alcohols include ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, and the polyhydric alcohols mentioned above.

[0145] Typically, polyurethane is compounded with conductive agents to impart or adjust its conductivity. Various ionic and electronic conductive agents can be used as conductive agents, and it is also possible to use both ionic and electronic conductive agents in combination.

[0146] Examples of ionic conductive agents include ammonium salts such as perchlorates, chlorates, hydrochlorides, bromates, iodates, borofluorides, sulfates, ethyl sulfates, carboxylates, and sulfonates of alkali metals and alkaline earth metals such as lithium, sodium, potassium, calcium, and magnesium.

[0147] Examples of electronically conductive materials include conductive carbons such as Ketjenblack and acetylene black; rubber carbons such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, and MT; oxidized carbons for inks, pyrolysis carbons, natural graphite, and artificial graphite; conductive metal oxides such as tin oxide, titanium oxide, and zinc oxide; and metals such as nickel, copper, silver, and germanium.

[0148] Furthermore, in addition to polyol components, isocyanate components, and conductive agents, polyurethane can be mixed with appropriate amounts of known additives such as foam stabilizers, crosslinking agents, surfactants, catalysts, and polymerization initiators, as needed.

[0149] Catalysts used in the curing reaction of polyurethane include monoamines such as triethylamine and dimethylcyclohexylamine; diamines such as tetramethylethylenediamine, tetramethylpropanediamine, and tetramethylhexanediamine; triamines such as pentamethyldiethylenetriamine, pentamethyldipropylenetriamine, and tetramethylguanidine; cyclic amines such as triethylenediamine, dimethylpiperazine, methylethylpiperazine, methylmorpholine, dimethylaminoethylmorpholine, and dimethylimidazole; alcohol amines such as dimethylaminoethanol, dimethylaminoethoxyethanol, trimethylaminoethylethanolamine, methylhydroxyethylpiperazine, and hydroxyethylmorpholine; ether amines such as bis(dimethylaminoethyl) ether and ethylene glycol bis(dimethyl)aminopropyl ether; stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, and dibutyltin markers. Examples of catalysts include organometallic compounds such as mercaptide, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin mercaptide, dioctyltin thiocarboxylate, phenylmercury propionate, and lead octenoate. These catalysts may be used individually or in combination of two or more.

[0150] Examples of foaming agents include water, polydimethylsiloxane-polyethylene oxide copolymer, polydimethylsiloxane-polypropylene oxide copolymer, and polydimethylsiloxane-polyethylene adipate copolymer.

[0151] As the silicone foam stabilizer, dimethylpolysiloxane - polyoxyalkylene copolymers etc. are preferably used, and those composed of a dimethylpolysiloxane part with a molecular weight of 350 to 15,000 and a polyoxyalkylene part with a molecular weight of 200 to 4,000 are particularly preferred. The molecular structure of the polyoxyalkylene part is preferably an addition polymer of ethylene oxide or a copolymer of ethylene oxide and propylene oxide, and it is also preferable that the molecular terminal is ethylene oxide.

[0152] Examples of the surfactant include ionic surfactants such as cationic surfactants, anionic surfactants, and amphoteric surfactants, and nonionic surfactants such as various polyethers and various polyesters.

[0153] The foam stabilizer and the surfactant may be used alone or in combination of two or more. The blending amount of the silicone foam stabilizer and various surfactants is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, based on 100 parts by mass of the total amount of the polyisocyanate and the polyol.

[0154] When the polyurethane contained in the elastic layer is foamed polyurethane (polyurethane foam), as the foaming method of the polyurethane foam raw material, methods such as the conventionally used mechanical froth method, water foaming method, and blowing agent froth method can be used. In particular, it is preferable to use the mechanical froth method in which foaming is carried out by mechanical stirring while mixing an inert gas.

[0155] From the viewpoint of obtaining a high - quality image when applied to an image forming apparatus, the volume resistivity of the elastic layer is preferably 104 Ω or more, more preferably 104.5 Ω or more, still more preferably 105 Ω or more, even more preferably 106 Ω or more, even more preferably 107 Ω or more, and preferably 1010 Ω or less, more preferably 109.5 Ω or less, still more preferably 109 Ω or less, even more preferably 108.5 Ω or less, even more preferably 108 Ω or less.

[0156] The volume resistivity of the elastic layer can be measured, for example, by placing a measuring roller on a metal plate, applying a load of 500g to both ends of the roller, applying 100V between the shaft 12 and the metal plate, and measuring the resistance after 5 seconds using a resistance measuring instrument (ADVANTEST, R8340).

[0157] The thickness of the elastic layer also depends on the radius of the developing roller. For example, if the developing roller has a radius of 5 to 20 mm, the thickness of the elastic layer is preferably 2 to 15 mm, more preferably 2 to 10 mm, and even more preferably 3 to 8 mm.

[0158] The Asker C hardness of the elastic layer is preferably 40 to 80°, more preferably 45 to 70°, and even more preferably 50 to 60°. The Asker C hardness is a value measured according to JIS K 7312:1996. When the Asker C hardness is within the above range, for example, if the conductive roller is a developing roller, it is the optimal hardness range for contact with the photoreceptor, which is thought to suppress toner degradation, break up toner clumps, eliminate uneven development, and result in higher quality images.

[0159] When using polyurethane foam as the elastic layer, an isocyanate component, a polyol component, a conductive agent, and additives as needed are mixed together. For example, it can be obtained by mechanically stirring and foaming the foam, then pouring it into a mold in which a shaft (core) is set, and heat-curing it to form an elastic layer made of polyurethane foam around the shaft.

[0160] For the elastic layer, a UV-curable resin material such as the UV-curable resin material described in Japanese Patent Publication No. 2012-159736 can be used.

[0161] As the elastic layer, a UV-curable resin material, such as the UV-curable resin material described in Japanese Patent Publication No. 2012-159736, can be used.

[0162] UV-curable resin materials can be obtained by irradiating UV light with, for example, (A) urethane (meth)acrylate oligomer, (B) (meth)acrylate monomer, (C) ionic conductive agent, and (D) photopolymerization initiator. They can also be obtained by fixing and rotating the shaft (shaft, core) and forming a UV-curable elastic layer around the shaft using methods such as die coating, curtain coating, comma coating, or spray coating.

[0163] [surface] The developing roller 21 of the present invention preferably has a surface layer 24 formed directly or indirectly on the outer circumference of the elastic layer 23. Although there may be an adhesive layer or an intermediate layer between the elastic layer 23 and the surface layer 24, it is preferable that the surface layer 24 is formed directly on the surface of the elastic layer 23. This corresponds to the layer that comes into contact with the surface of the photoreceptor in an electrophotographic apparatus.

[0164] The surface layer can be formed using various solvent-based coatings such as urethane-based, acrylic-based, acrylic-urethane-based, and fluorine-based coatings. Among these, it is preferable that the surface layer contains polyurethane as a resin component. It is also preferable to use at least one selected from the group consisting of urethane resin fine particles, acrylic resin fine particles, fluorine resin fine particles, silicone resin fine particles, and silica fine particles. It is preferable to adjust the surface roughness by including the above-mentioned fine particles.

[0165] The surface layer may contain conductive agents (electronic conductive agents such as carbon black, and ionic conductive agents), vulcanizing agents, vulcanization accelerators, and anti-aging agents as appropriate. Among these, it is preferable to include a conductive agent to further enhance the conductivity of the surface layer, thereby obtaining higher-quality images. As the conductive agent, at least one selected from ionic conductive agents and electronic conductive agents may be used, and two or more may be used in combination. Examples of ionic conductive agents include the ionic conductive agents exemplified in the elastic layer. Examples of electronic conductive agents include fine particles of metal oxides such as ITO, tin oxide, titanium oxide, and zinc oxide; fine particles of metals such as nickel, copper, silver, and germanium; and developable whiskers such as developable titanium oxide whiskers and developable barium titanate whiskers. Furthermore, as the electronically conductive agent, developable carbon such as Ketjenblack and acetylene black, rubber carbon black such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, and MT, color carbon black that has undergone oxidation treatment, pyrolysis carbon black, natural graphite, artificial graphite, etc. can be used.

[0166] The surface layer can be formed by applying a predetermined solvent-based coating to the elastic layer using known methods such as dip coating, spray coating, or roll coater coating, drying it, and then heat-curing it as desired.

[0167] When the surface layer contains polyurethane, the surface layer composition for forming the surface layer preferably contains polyisocyanate and polyol, and in addition, preferably contains the conductive agent, anti-aging agent, etc. mentioned above. Furthermore, it is preferable to include a catalyst to promote the reaction between the polyisocyanate and polyol, and an example of such a catalyst is the urethane catalyst exemplified in the elastic layer.

[0168] Examples of polyisocyanates and polyols include the compounds exemplified in the elastic layer. When the surface layer contains polyurethane, it is preferable that the polyurethane be rubbery rather than foamy.

[0169] The thickness of the surface layer also depends on the radius of the developing roller. For example, if the developing roller has a radius of 3 to 10 mm, the thickness of the surface layer is preferably 1 to 50 μm, more preferably 2 to 30 μm, and even more preferably 10 to 30 μm.

[0170] From the viewpoint of obtaining high-quality images when applied to an image forming apparatus, the volume resistivity is preferably 105Ω or more, more preferably 105.5Ω or more, even more preferably 106Ω or more, even more preferably 107Ω or more, even more preferably 108Ω or more, preferably 1011Ω or less, more preferably 1010.5Ω or less, even more preferably 1010Ω or less, even more preferably 109.5Ω or less, and even more preferably 109 or less.

[0171] [Electrophotographic device] The electrophotographic apparatus according to the present invention comprises an electrophotographic photoreceptor, a charging means, an exposure means, and a developing means as described above. The charging means charges the surface of the electrophotographic photoreceptor. The exposure means irradiates the charged surface of the electrophotographic photoreceptor with light to form an electrostatic latent image on the surface of the electrophotographic photoreceptor. The developing means contains toner and develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with the toner to form a toner image on the surface of the electrophotographic photoreceptor. Furthermore, the developing means is a developing roller as described above.

[0172] The present invention will be described in detail below based on the illustrated embodiments.

[0173] The electrophotographic apparatus will be described below with reference to Figure 8. Figure 8 is a cross-sectional view showing an example of an electrophotographic apparatus. The electrophotographic apparatus 100 shown in Figure 8 comprises a developing device 33 as a developing means, an image carrier unit 44 as an image carrier, an exposure device 34 as an exposure means, and a transfer device 45 as a transfer means. As a developing means, the developing device 33 comprises a developing roller 30, a toner supply roller 32, and a layering blade 31. The image carrier unit 44 comprises an image carrier 40 (specifically, a single-layer photoreceptor or a multilayer photoreceptor), a charging device 41 as a charging means (specifically, a corona charger), a cleaning member 42a as an image carrier cleaning member, a conductor 42b (specifically, a metal rod), and a pre-exposure device 43. The recording medium P is located at the bottom of the electrophotographic apparatus. The image carrier 40 is provided in the central position, and the image carrier is rotatable in the clockwise direction in Figure 8. Around the image carrier, in the order listed from the upstream side in the rotational direction of the image carrier, are a charging device 41, an exposure device 34, a developing unit 33, and a transfer device 45.

[0174] The charging device 41 charges the surface (e.g., the circumferential surface) of the image carrier 40 with positive polarity. If the photoreceptor 40 is a single-layer photoreceptor, the surface of the image carrier 40 is charged with positive polarity. The charging device 41 is, for example, a corona charger. The exposure device 34 irradiates the charged surface of the image carrier 40 with exposure light. That is, the exposure device 34 exposes the surface of the charged image carrier 40. This forms an electrostatic latent image on the surface of the image carrier 40. The electrostatic latent image is formed based on the image data input to the electrophotographic apparatus 100. The developing device 33 has toner and supplies toner to the surface of the image carrier 40, developing the electrostatic latent image as a toner image. The developing device 33 (for example, the surface of the developing roller 30 in the developing device 33, more specifically the circumferential surface of the developing roller 30) is in contact with the surface of the image carrier 40. That is, the electrophotographic apparatus 100 employs a contact developing method. The developing device 33 is, for example, a developing roller. When the developer is a one-component developer, the developing device 33 supplies toner, which is a one-component developer, to the electrostatic latent image formed on the image carrier 40. When the developer is a two-component developer, the developing device 33 supplies toner, which is one of the toners and carriers contained in the two-component developer, to the electrostatic latent image formed on the image carrier 40. In this way, the image carrier 40 carries a toner image. The transfer device 45 transports the recording medium P between the image carrier 40 and the transfer device 45. The transfer device 45 transfers the toner image developed by the developing device 33 from the surface of the image carrier 40 to the transfer target. The transfer target is the recording medium P. When the toner image is transferred, the image carrier 40 is in contact with the recording medium P. That is, the electrophotographic apparatus 100 employs a direct transfer method. The transfer device 45 is, for example, a transfer roller. The recording medium P onto which the toner image has been transferred by the transfer device 45 is then fixed by a fixing device (not shown), which is, for example, a heating roller and / or a pressure roller. The unfixed toner image transferred by the transfer device 45 is heated and / or pressurized by the fixing device. The toner image is fixed to the recording medium P by the heating and / or pressurization. As a result, an image is formed on the recording medium P. The above describes an example of an electrophotographic apparatus, but the electrophotographic apparatus is not limited to the electrophotographic apparatus 100 already described.Although the electrophotographic apparatus 100 described above was a monochrome electrophotographic apparatus, the electrophotographic apparatus may also be a color electrophotographic apparatus. In this case, the electrophotographic apparatus may, for example, be equipped with a plurality of developing devices 33 and an image carrying unit 44. The electrophotographic apparatus 100 may also employ, for example, a tandem system or a rotary system. Corona charging was used as an example of the charging device 41 in the explanation, but the charging device may also be a charging roller and another non-contact charging device (for example, a scorotron charger, a charging brush, or a corotron charger). Although the electrophotographic apparatus 100 described above employed a contact developing method, the electrophotographic apparatus may also employ a non-contact developing method. Although the electrophotographic apparatus 100 described above employed a direct transfer method, the electrophotographic apparatus may also employ an intermediate transfer method. When the electrophotographic apparatus employs an intermediate transfer method, the object to be transferred corresponds to an intermediate transfer belt. The electrophotographic apparatus is equipped with a cleaning member on the image carrying unit 44 described above, but it may further be equipped with another cleaning member (for example, a cleaning blade). Although the image-carrying unit 44 mentioned earlier is equipped with a static elimination device, it is not necessary to have one.

[0175] [Processing cartridge] The process cartridge according to the present invention is Electrophotographic photoreceptor, and A charging means for charging the surface of the electrophotographic photoreceptor, A contact developing means comprising toner and a developing roller, for developing an electrostatic latent image formed on the surface of an electrophotographic photoreceptor by bringing the developing roller, on which the toner is carried, into contact with the electrophotographic photoreceptor. A process cartridge characterized by integrally supporting the main body of an electrophotographic apparatus and being detachable from the main body of the electrophotographic apparatus, The electrophotographic photoreceptor has a surface layer containing a binder resin, The aforementioned surface layer The aforementioned binder resin contains a polyester resin having structural units represented by the following formula (1) and structural units represented by the following formula (2). The toner carrier is a developing roller having a shaft and an elastic layer provided on the outer circumference of the shaft. The elastic layer contains urethane rubber. This is a process cartridge characterized by the following features.

[0176] [ka]

[0177] [ka]

[0178] Referring to Figure 8, an example of a process cartridge according to an embodiment of the present invention will be described. The process cartridge corresponds to a combination of a developing device 33 and an image carrying unit 44. The process cartridge comprises an image carrier 40 and a developing device 33. The image carrier 40 and the developing device 33 are integrally supported by the frame 50 of the process cartridge. The image carrier 40 is the photoreceptor of the first embodiment. In addition to the image carrier 40 and the developing device 33, the process cartridge may further include a charging device 41. The process cartridge may further include a cleaning member 42a and a static elimination device 43. The process cartridge is designed to be detachably attached to the electrophotographic apparatus 100. Therefore, the process cartridge is easy to handle, and if the sensitivity characteristics of the image carrier 40 deteriorate, it can be easily and quickly replaced, including the image carrier 40. The process cartridge comprising a photoreceptor has been described above with reference to Figure 8. [Examples]

[0179] The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited in any way by the following examples, unless it exceeds the gist of the invention. In the following descriptions of examples, "parts" refers to mass unless otherwise specified.

[0180] <Manufacturing of polyester resin (PAR)> [Synthesis of resin (PAR-1)] A three-necked flask equipped with a thermometer, a three-way stopcock, and a dropping funnel was used as the reaction vessel. The following materials were placed in the reaction vessel. • The monomer compound (BP-2) (41.0 mmol) • The terminal inhibitor is 2,6-dimethylphenol (DMP) (0.625 mmol). • Sodium hydroxide (98 mmol) • Benzyltributylammonium chloride (0.384 mmol)

[0181] The air in the reaction vessel was replaced with argon gas. Water (300 mL) was added to the contents of the reaction vessel. The contents of the reaction vessel were stirred at 50°C for 1 hour. The contents of the reaction vessel were cooled to 10°C to obtain alkaline aqueous solution A1.

[0182] Next, dicarboxylic acid dichloride (32.0 mmol), a derivative of the monomer compound (DC-1), was dissolved in chloroform (150 mL). This yielded chloroform solution B1.

[0183] To an alkaline aqueous solution A1, chloroform solution B1 was slowly added dropwise over 110 minutes using a dropping funnel. The contents of the reaction vessel were stirred for 4 hours while adjusting the temperature (liquid temperature) of the contents to 15±5°C to allow the polymerization reaction to proceed. The upper layer (aqueous layer) of the contents of the reaction vessel was removed using a decanter to obtain the organic layer. Next, ion-exchanged water (400 mL) was added to an Erlenmeyer flask. The obtained organic layer was further added to the Erlenmeyer flask. Chloroform (400 mL) and acetic acid (2 mL) were further added to the Erlenmeyer flask. The contents of the Erlenmeyer flask were stirred at room temperature (25°C) for 30 minutes. The upper layer (aqueous layer) of the contents of the Erlenmeyer flask was removed using a decanter to obtain the organic layer. The obtained organic layer was washed with ion-exchanged water (1 L) using a separatory funnel. The washing with ion-exchanged water was repeated 5 times to obtain a water-washed organic layer. Next, the water-washed organic layer was filtered to obtain the filtrate. The obtained filtrate was slowly added dropwise to methanol (1 L) to obtain a precipitate. The precipitate was removed by filtration. The removed precipitate was vacuum-dried at 70°C for 12 hours. As a result, a resin (PAR-1) with a viscosity-average molecular weight of 35,000 was obtained.

[0184] [Synthesis of resin (PAR-52)] A three-necked flask equipped with a thermometer, a three-way stopcock, and a dropping funnel was used as the reaction vessel. The following materials were placed in the reaction vessel. • The monomer compound (BP-2) (28.7 mmol) • The monomer compound (BP-5) (12.3 mmol) • The terminal inhibitor is 2,6-dimethylphenol (DMP) (0.413 mmol). • Sodium hydroxide (98 mmol) • Benzyltributylammonium chloride (0.384 mmol)

[0185] The air in the reaction vessel was replaced with argon gas. Water (300 mL) was added to the contents of the reaction vessel. The contents of the reaction vessel were stirred at 50°C for 1 hour. The contents of the reaction vessel were cooled to 10°C to obtain alkaline aqueous solution A2.

[0186] Next, dicarboxylic acid dichloride (20.8 mmol), a derivative of the monomer compound (DC-1), and dicarboxylic acid dichloride (11.2 mmol), a derivative of the monomer compound (DC-4), were dissolved in chloroform (150 mL). This yielded chloroform solution B2.

[0187] To an alkaline aqueous solution A2, chloroform solution B2 was slowly added dropwise over 110 minutes using a dropping funnel. The contents of the reaction vessel were stirred for 4 hours while adjusting the temperature (liquid temperature) to 15±5°C to allow the polymerization reaction to proceed. The upper layer (aqueous layer) of the contents of the reaction vessel was removed using a decanter to obtain the organic layer. Next, 400 mL of deionized water was added to an Erlenmeyer flask. The obtained organic layer was then added to the Erlenmeyer flask. 400 mL of chloroform and 2 mL of acetic acid were then added to the Erlenmeyer flask. The contents of the Erlenmeyer flask were stirred at room temperature (25°C) for 30 minutes. The upper layer (aqueous layer) of the contents of the Erlenmeyer flask was removed using a decanter to obtain the organic layer. The obtained organic layer was washed with 1 L of deionized water using a separatory funnel. The washing with deionized water was repeated 5 times to obtain a water-washed organic layer. Next, the water-washed organic layer was filtered to obtain the filtrate. The obtained filtrate was slowly added dropwise to 1 L of methanol to obtain a precipitate. The precipitate was removed by filtration. The removed precipitate was vacuum-dried at 70°C for 12 hours. As a result, a resin (PAR-52) with a viscosity-average molecular weight of 53600 was obtained.

[0188] [Synthesis of resins (PAR-2) to (PAR-51), (PAR-53) to (PAR-110), and (PAR-201) to (PAR-205)] Except for changing the ratio of bisphenol and dicarboxylic acid, and the end-stop agent, the resin (PAR) with a viscosity-average molecular weight of 53600 was synthesized using the same method as for resin (PAR-52), and resins (PAR) with the viscosity-average molecular weights shown in Table 1 were obtained. Note that the viscosity-average molecular weight of the resin (PAR) increases as the amount of end-stop agent added decreases.

[0189] [Table 1]

[0190] [Table 2]

[0191] [Table 3]

[0192] Tables 1, 2, and 3 show the bisphenol values ​​as the ratio of the amount of each bisphenol to the total amount of two bisphenols in resins (PAR-1) to (PAR-110) and resins (PAR-201) to (PAR-203). Similarly, the dicarboxylic acid values ​​represent the ratio of the amount of each dicarboxylic acid to the total amount of two dicarboxylic acids. PFH stands for 1H,1H-perfluoro-1-heptanol. Molecular weight is the viscosity-average molecular weight.

[0193] <Manufacturing of electrophotographic photoconductors> [Manufacturing of Photoreceptor 1] The following materials were prepared. • 2.0 parts by mass of Y-type crystals of titanylphthalocyanine represented by formula (CGM-1), which is a charge-generating material. • Hole transport material (H-11) 70.0 parts by mass ·Electron transport material (E-4) 40.0 parts by mass • Additive (30) 14.0 parts by mass • 100.0 parts by mass of polyester resin (PAR-1) as a binder. • 500.0 parts by mass of tetrahydrofuran, which is a solvent.

[0194] The above materials were mixed for 20 minutes using a rod-shaped sonic oscillator to obtain a dispersion. The dispersion was filtered using a 5 μm mesh filter to obtain a coating solution for the photosensitive layer. The coating solution for the photosensitive layer was applied to a conductive support (aluminum drum-shaped support) by dip coating and dried with hot air at 120°C for 50 minutes. In this way, a photosensitive layer (film thickness 30 μm) was formed on the conductive support to obtain photoreceptor 1.

[0195] (Analysis of the resin components of photoreceptor 1) The polymer components recovered from the obtained photoreceptor in deuterated chloroform 1 H-nuclear magnetic resonance analysis, 1 ¹H-NMR spectra were obtained. The obtained ¹H-NMR spectra had peaks at 8.22±0.02, 7.18±0.02, 7.16±0.02, 7.10±0.02, 7.06±0.02, and 7.04±0.02 ppm. This identified that the photoreceptor contained structural units represented by formula (1) and formula (2). Furthermore, the ratio of the amount of substance between the structural units represented by formula (1) and formula (2) was 1:1, as determined from the integral ratio of the above peaks, and is shown in PAR-1 of Table 1.

[0196] [Manufacturing of photoreceptors 2-100 and 201-203] Photoreceptors 2-100 and 201-203 were manufactured using the same method as photoreceptor 1, except that the types of charge generating material, additives, hole transport material, electron transport material, and binder resin were changed. Table 2 shows the types of charge generating material, additives, hole transport material, electron transport material, and binder resin used. The mass of each material used is the same as that of photoreceptor 1. Tables 4, 5, and 6 show examples of photoreceptor manufacturing. In the tables, CGM represents the charge generating material, HTM represents the hole transport material, and ETM represents the electron transport material, with each indicating its compound number.

[0197] (Analysis of the resin components of photoreceptor 30) The polymer components recovered from the obtained photoreceptor in deuterated chloroform 1 H-nuclear magnetic resonance analysis, 1 The 1H-NMR spectrum was obtained. 1The 1H-NMR spectrum had peaks at 8.22±0.02, 7.18±0.02, 7.16±0.02, 7.10±0.02, 7.06±0.02, 7.04±0.02, 2.28±0.02, 2.20±0.02, 1.59±0.02, and 1.54±0.02 ppm. This identified that the photoreceptor contained structural units represented by formula (1), formula (2), formula (4), and formula (5). Furthermore, the proportions of the amounts of the structural units represented by formula (1), formula (2), formula (4), and formula (5) were as shown in PAR-30 of Table 2, based on the integral ratio of the above peaks.

[0198] <Measurement of Vickers hardness> The Vickers hardness of the photosensitive layer was measured for representative photosensitive materials shown in Tables 4, 5, and 6. Specifically, the Vickers hardness of the photosensitive layer was measured according to the method compliant with JIS (Japanese Industrial Standards) Z2244. A hardness tester ("Micro Vickers Hardness Tester DMH-1" manufactured by Matsuzawa Co., Ltd. (formerly Matsuzawa Seiki Co., Ltd.)) was used to measure the Vickers hardness. The Vickers hardness was measured under the following conditions: temperature 23°C, diamond indenter load (test force) 10 gf, time required to reach the test force 5 seconds, diamond indenter approach speed 2 mm / second, and test force holding time 1 second. The measured Vickers hardness is shown in Tables 4, 5, and 6.

[0199] [Table 4]

[0200] [Table 5]

[0201] [Table 6]

[0202] <Manufacturing of developing rollers> Developing rollers 1-4 were obtained using the following method.

[0203] [Manufacturing of developing roller 1] (Manufacturing of elastic layers) An isocyanate component comprising 100 parts by mass of prepolymerized tolylene diisocyanate (TDI) (manufactured by Asahi Glass Co., Ltd., 800BP) and 25 parts by mass of conductive carbon black (manufactured by Asahi Carbon Co., Ltd., SB805), and 12.5 parts by mass of ester polyol (manufactured by Kuraray Co., Ltd., F510, a compound of trifunctional alcohol and adipic acid, molecular weight 500), and 12.5 parts by mass of ester polyol (manufactured by Kuraray Co., Ltd., F1010, a compound of trifunctional alcohol and adipic acid, molecular weight 1000), and ether polyol ( A polyol component was prepared by mixing 25 parts by mass of FA951 (polyoxyalkylene polyol) manufactured by Sanyo Chemical Industries, Ltd., 3 parts by mass of a foam stabilizer (SF2937F) manufactured by Toray Dow Corning Co., Ltd., 0.05 parts by mass of a catalyst (U-100) manufactured by Nitto Chemical Co., Ltd., 2 parts by mass of aliphatic quaternary ammonium sulfate (KS-48) manufactured by Kao Corporation, and 0.3 parts by mass of sodium perchlorate (MP-100) manufactured by Showa Chemical Industry Co., Ltd.). This mixture was foamed using the mechanical flossing method and injected into a mold set with a metal shaft (φ7.5 mm). Subsequently, this mixture was heat-cured at 120°C for 30 minutes to form a 4 mm thick elastic layer on the outer circumference of the metal shaft. The Asker C hardness of the obtained elastic layer was measured using an Asker C hardness tester [Polymer Instruments Co., Ltd.] and was found to be 52°.

[0204] (Surface layer manufacturing) To prepare the surface coating, 100 parts by mass of polytetramethylene glycol ether polyol (manufactured by Hodogaya Chemical Co., Ltd., PTG1000SN: OH value 112 mg KOH / g), 5 parts by mass of carbon black (carbon black manufactured by Mitsubishi Chemical Corporation, MA600), and 10 parts by mass of urethane particles (manufactured by Negami Kogyo, product name: Art Pearl C800, average particle size 8.8 μm) were dispersed in 350 parts by mass of methyl ethyl ketone (MEK). Next, 40 parts by mass of isocyanate curing agent (manufactured by Tosoh Corporation, Coronate Hx: NCO%=21%, a polyisocyanate compound based on hexamethylene diisocinate) were added, and the mixture was stirred with a stirring motor for 30 minutes. The surface coating was then applied to the shaft with the elastic layer by dipping and dried at 105°C for 120 minutes to form a surface layer with a thickness of 20 μm.

[0205] [Manufacturing of developing roller 2] (Manufacturing of elastic layers) An isocyanate component was prepared by combining 100 parts by mass of isophorone diisocyanate (IPDI) and 25 parts by mass of conductive carbon black (Asahi Carbon Co., Ltd., SB805). A polyol component was prepared by combining 50 parts by mass of ether-based polyol (polypropylene glycol (PPG)), 3 parts by mass of foam stabilizer (Toray Dow Corning Co., Ltd., SF2937F), 0.05 parts by mass of catalyst (Nitto Chemical Co., Ltd., U-100), 2 parts by mass of aliphatic quaternary ammonium sulfate (Kao Corporation, KS-48), and 0.3 parts by mass of sodium perchlorate (Showa Chemical Industry Co., Ltd., MP-100). This mixture was foamed using a mechanical flossing method and injected into a mold set with a metal shaft (φ7.5 mm). Subsequently, this mixture was heat-cured at 120°C for 30 minutes to form a 4 mm thick elastic layer on the outer circumference of the metal shaft. The Asker C hardness of the obtained elastic layer was measured using an Asker C hardness tester [Polymer Instruments Co., Ltd.] and was found to be 56°.

[0206] (Surface layer manufacturing) 100 parts by mass of lactone-modified polyol (manufactured by Daicel Chemical Industries, trade name: PCL220AL, OH value 56), 30 parts by mass of carbon black, 10 parts by mass of urethane particles (manufactured by Negami Kogyo, trade name: Art Pearl C800, average particle size 8.8 μm), and 10 parts by mass of silicone resin particles (manufactured by Shin-Etsu Silicone Co., Ltd., standard name: KMP605) were dispersed in 480 parts by mass of methyl ethyl ketone (MEK). Then, 33 parts by mass of isophorone diisocyanate (IPDI) (manufactured by Degussa Hürs, trade name: Vestanate T1890E, NCO%=12%) and 15 parts by mass of hexamethylene diisocyanate (HMDI) (manufactured by Nippon Polyurethane, trade name: Coronate Hx, NCO%=21%) were added, and the mixture was stirred with a stirring motor for 30 minutes to prepare a surface coating. The surface coating was applied to the elastic layered shaft by dipping and dried at 105°C for 120 minutes to form a surface layer with a thickness of 20 μm.

[0207] [Manufacturing of the developing roller 3] (Manufacturing of elastic layers) An isocyanate component was prepared by combining 100 parts by mass of tolylene diisocyanate (TDI) and 25 parts by mass of conductive carbon black (Asahi Carbon Co., Ltd., SB805). A polyol component was prepared by combining 50 parts by mass of ether-based polyol (polypropylene glycol (PPG)), 3 parts by mass of foam stabilizer (Toray Dow Corning Co., Ltd., SF2937F), 0.05 parts by mass of catalyst (Nitto Chemical Co., Ltd., U-100), 2 parts by mass of aliphatic quaternary ammonium sulfate (Kao Corporation, KS-48), and 0.3 parts by mass of sodium perchlorate (Showa Chemical Industry Co., Ltd., MP-100). This mixture was foamed using a mechanical flossing method and injected into a mold set with a metal shaft (φ7.5 mm). Subsequently, this mixture was heat-cured at 120°C for 30 minutes to form a 4 mm thick elastic layer on the outer circumference of the metal shaft. The Asker C hardness of the obtained elastic layer was measured using an Asker C hardness tester [Polymer Instruments Co., Ltd.] and was found to be 60°.

[0208] (Surface layer manufacturing) 100 parts by mass of lactone-modified polyol (manufactured by Daicel Chemical Industries, trade name: PCL220AL, OH value 56), 30 parts by mass of carbon black, and 10 parts by mass of urethane particles (manufactured by Negami Kogyo, trade name: Art Pearl C800, average particle size 8.8 μm) were dispersed in 480 parts by mass of methyl ethyl ketone (MEK). Next, 33 parts by mass of isophorone diisocyanate (IPDI) (manufactured by Degussa Hürs, trade name: Vestanate T1890E, NCO%=12%) and 15 parts by mass of hexamethylene diisocyanate (HMDI) (manufactured by Nippon Polyurethane, trade name: Coronate Hx, NCO%=21%) were added, and the mixture was stirred with a stirring motor for 30 minutes to prepare a surface coating. The surface coating was applied to the shaft with the elastic layer by dipping and dried at 105°C for 120 minutes to form a surface layer with a thickness of 20 μm.

[0209] [Manufacturing of the developing roller 4] (Manufacturing of elastic layers) An isocyanate component was prepared by combining 100 parts by mass of isophorone diisocyanate (IPDI) and 25 parts by mass of conductive carbon black (Asahi Carbon Co., Ltd., SB805). A polyol component was prepared by combining 50 parts by mass of ether-based polyol (polypropylene glycol (PPG)), 3 parts by mass of foam stabilizer (Toray Dow Corning Co., Ltd., SF2937F), 0.05 parts by mass of catalyst (Nitto Chemical Co., Ltd., U-100), 2 parts by mass of aliphatic quaternary ammonium sulfate (Kao Corporation, KS-48), and 0.3 parts by mass of ionic conductive agent (lithium salt) (Mitsubishi Materials Corporation, product name "EF-N115"). This mixture was foamed using a mechanical flossing method and injected into a mold set with a metal shaft (φ7.5 mm). Subsequently, this mixture was heat-cured at 120°C for 30 minutes to form a 4 mm thick elastic layer on the outer circumference of the metal shaft. The Asker C hardness of the obtained elastic layer was measured using an Asker C hardness tester [Polymer Instruments Co., Ltd.] and was found to be 56°.

[0210] (Surface layer manufacturing) 100 parts by mass of lactone-modified polyol (manufactured by Daicel Chemical Industries, trade name: PCL220AL, OH value 56), 0.5 parts by mass of dioctyltin, and 50 parts by mass of tolylene diisocyanate (TDI) were reacted under vacuum with heating and stirring in propylene glycol 1-monomethyl ether 2-acetate (PMA) solvent. After the peak intensity of isocyanate saturated by infrared (IR) spectroscopy, hydroxyethyl acrylate (HEA) was added, and a urethane acrylate coating was obtained when the isocyanate peak disappeared by IR spectroscopy. The mass ratio of lactone-modified polyol to TDI (lactone-modified polyol / TDI) was 1.95.

[0211] A surface coating was prepared by blending 35 parts by mass of a surface roughening agent: polytetrafluoroethylene resin particles [manufactured by 3M Co., Ltd., product name "TF9207"] and 2 parts by mass of an ultraviolet curing agent: α-aminoalkylphenone [manufactured by BASF, product name "Irgacure907"] with 100 parts by mass of the urethane acrylate.

[0212] Next, the surface layer was coated to a thickness of approximately 1 μm using the roll-coating method, and then irradiated with UV light (intensity 3000 mW / cm2, duration 10 seconds, 25°C) under a nitrogen atmosphere to form the surface layer.

[0213] <Examples> [evaluation] Image defects (density unevenness) were evaluated for each of the photoreceptor and developing roller using the method described below. A modified electrophotographic device (Brother's monochrome LBP "HL-L6310") was used as the evaluation machine. The process cartridge for this evaluation machine was equipped with a corona charger as the charging device. The charging polarity was positive. The developing device was equipped with a developing roller and used a one-component contact developing method. The developing roller was removed from the developing unit in the process cartridge and each manufactured developing roller was installed. The photoreceptor was removed from the photoreceptor unit in the process cartridge and the manufactured photoreceptor was installed.

[0214] [Image density unevenness evaluation] The manufactured photoreceptor and process cartridge, equipped with a developing roller, were left in an environment of 50°C and 95% RH for one month. The process cartridge was then mounted in an electrophotographic apparatus and subjected to an intermittent test of 40,000 prints under conditions of 35°C and 80% RH. The test involved printing two images per job with a print density of 1%, with the apparatus stopping briefly between jobs before starting the next job. After the test, halftone images and horizontal line pattern images (four horizontal dots printed at 176-dot intervals) were output and evaluated. The paper used was plain paper CS-680 (68g / m2) (Canon Marketing Japan Inc.).

[0215] (Density variations in halftone images) Density uniformity was evaluated by creating a halftone (20H) image and assessing its density uniformity based on the following criteria. The paper used was plain paper CS-680 (68g / m2) (Canon Marketing Japan Inc.). A 20H image is a halftone image where 256 gradations are represented in hexadecimal, with 00H representing solid white (no image) and FFH representing solid black (full image). The evaluation criteria were as follows: Density measurements were taken at 20 locations, and the difference between the maximum and minimum density values ​​(density uniformity) was used for determination as follows. Density was measured using an X-Rite color reflectance densitometer (X-rite 500 Series). A: Concentration uniformity is less than 0.04 B: Concentration uniformity is 0.04 or higher and less than 0.06 C: Concentration uniformity is 0.06 or higher and less than 0.08. D: Concentration uniformity is 0.08 or higher and less than 0.10 E: Concentration uniformity is 0.10 or higher

[0216] (White gaps in horizontal line pattern image) Since the image is linear, we evaluated line defects, i.e., white spots, rather than density variations. We observed the output image using a 25x magnification loupe and evaluated it using the following criteria. A: When observed with a 25x magnification loupe, no white spots were observed. B: When observed with a 25x magnification loupe, several areas of whiteness appear around the edges of the image. C: When observed with a 25x magnification loupe, numerous white areas appear around the edges of the image. D: White spots can be observed even with the naked eye. E: Clear white areas are visible to the naked eye.

[0217] The evaluation results are shown in Tables 7 and 8.

[0218] [Table 7]

[0219] [Table 8]

[0220] Examples 1 to 40, which use a photoreceptor containing polyester resin and a developing roller according to the present invention, show suppression of image defects (density unevenness) and maintain the quality of the output image throughout its lifespan.

[0221] On the other hand, the comparative example showed a large number of image defects.

[0222] This embodiment includes the following configurations and methods.

[0223] (Composition 1) Electrophotographic photoreceptor, and A contact developing means comprising toner and a developing roller, for developing an electrostatic latent image formed on the surface of an electrophotographic photoreceptor by bringing the developing roller, on which the toner is carried, into contact with the electrophotographic photoreceptor. An electrophotographic apparatus having, The electrophotographic photoreceptor has a surface layer containing a binder resin, The surface layer contains polyester resin as the binder resin, The polyester resin has structural units represented by the following formula (1) and structural units represented by the following formula (2), The developing roller has an elastic layer, The elastic layer contains urethane rubber, An electrophotographic apparatus characterized by this.

[0224]

Chemical formula

[0225]

Chemical formula

[0226] (Configuration 2) The electrophotographic apparatus according to Configuration 1, characterized in that the polyester resin further has a structural unit represented by the following formula (4) and a structural unit represented by the following formula (5).

[0227]

Chemical formula

[0232] (Composition 6) An electrophotographic apparatus according to any one of configurations 1 to 5, characterized in that the proportion of the polyester resin to the total mass of the binder resin is 50% by mass or more.

[0233] (Composition 7) The electrophotographic apparatus according to any one of configurations 1 to 6, characterized in that the electrophotographic photoreceptor has a single-layer photosensitive layer having a charge generating material, a hole transporting material, and an electron transporting material.

[0234] (Composition 8) The electrophotographic apparatus according to any one of configurations 1 to 7, wherein the electron transport material includes at least one selected from the group consisting of a compound represented by the following formula (10), a compound represented by the following formula (11), a compound represented by the following formula (12), a compound represented by the following formula (13), a compound represented by the following formula (14), a compound represented by the following formula (15), and a compound represented by the following formula (16).

[0235] [ka]

[0236] [ka]

[0237] [ka]

[0238] [ka]

[0239] [ka]

[0240] [ka]

[0241] [ka]

[0242] (Q in equation (10) above) 1 and Q 2 , Q in equation (11) above 11 Q 12 , and Q 13 , Q in equation (12) above 21 Q 22 Q 23 , and Q 24 , Q in equation (13) above 31 and Q 32 Q in equation (14) above 41 Q 42 Q 43 , and Q 44 , Q in equation (15) above 51 Q 52 Q 53 Q 54 Q 55 , and Q 56 , and Q in formula (16) 61 and Q 62 Each independently represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 14 carbon atoms which may be substituted with at least one substituent selected from the group consisting of an alkyl group having 1 to 6 carbon atoms and a halogen atom, and Y in formula (15) 1 and Y 2 Each of these independently represents either an oxygen atom or a sulfur atom.

[0243] (Composition 9) The electrophotographic apparatus according to any one of configurations 1 to 8, wherein the electron transport material includes at least one selected from the group consisting of a compound represented by the following formula (E-1), a compound represented by the following formula (E-2), a compound represented by the following formula (E-3), a compound represented by the following formula (E-4), a compound represented by the following formula (E-5), a compound represented by the following formula (E-6), a compound represented by the following formula (E-7), and a compound represented by the following formula (E-8).

[0244] [ka]

[0245] [ka]

[0246] [ka]

[0247] [ka]

[0248] [ka]

[0249] [ka]

[0250] [ka]

[0251] [ka]

[0252] (Composition 10) The electrophotographic apparatus according to any one of configurations 1 to 9, wherein the hole transport material comprises at least one selected from the group consisting of a compound represented by the following formula (20), a compound represented by the following formula (21), a compound represented by the following formula (22), a compound represented by the following formula (23), and a compound represented by the following formula (24).

[0253] [ka]

[0254] [ka]

[0255] [ka]

[0256] [ka]

[0257] [ka]

[0258] (In the above formula (20), R 11 , R 12 , R 13 , and R 14 Each independently represents an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, and a 1 a 2 a 3 , and a 4 Each of these independently represents an integer between 0 and 5, and in formula (21) above, R 21 , R 22 , and R 23 Each of these independently represents an alkyl group having 1 to 6 carbon atoms, and R 24 , R 25 , and R 26Each of these independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and b 1 , b 2 , and b 3 Each independently represents either 0 or 1, and in formula (22) above, R 31 , R 32 , and R 33 Each of these independently represents an alkyl group having 1 to 6 carbon atoms, and R 34 represents an alkyl group or hydrogen atom having 1 to 6 carbon atoms, and d 1 d 2 , and d 3 Each of these independently represents an integer between 0 and 5, and in formula (23) above, R 41 , R 42 , R 43 , R 44 , R 45 , and R 46 Each independently represents an alkyl group having 1 to 6 carbon atoms, or a phenyl group, and R 47 and R 48 Each of these independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group, and e 1 , e 2 , e 3 , and e 4 Each of these independently represents an integer between 0 and 5, and e 5 and e 6 Each of these independently represents an integer between 0 and 4, and e 7 and e 8 Each independently represents either 0 or 1, and in formula (24) above, R 50 and R 51 Each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group, R 52 , R 53 , R 54 , R 55 , R 56 , R 57 , and R 58 Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms, f 1 and f 2Each of these independently represents an integer between 0 and 2, and f 3 and f 4 Each of these independently represents an integer between 0 and 5 (inclusive).

[0259] (Composition 11) The electrophotographic apparatus according to any one of configurations 1 to 10, wherein the hole transport material includes at least one selected from the group consisting of a compound represented by the following formula (H-1), a compound represented by the following formula (H-2), a compound represented by the following formula (H-3), a compound represented by the following formula (H-4), a compound represented by the following formula (H-5), a compound represented by the following formula (H-6), a compound represented by the following formula (H-7), a compound represented by the following formula (H-8), a compound represented by the following formula (H-9), a compound represented by the following formula (H-10), and a compound represented by the following formula (H-11).

[0260] [ka]

[0261] [ka]

[0262] [ka]

[0263] [ka]

[0264] [ka]

[0265] [ka]

[0266] [ka]

[0267] [ka]

[0268] [ka]

[0269] [ka]

[0270] [ka]

[0271] (Composition 12) The electrophotographic apparatus according to any one of configurations 1 to 11, wherein the charge-generating material contains titanylphthalocyanine.

[0272] (Composition 13) The electrophotographic apparatus according to any one of configurations 1 to 12, wherein the photosensitive layer contains a compound represented by formula (30).

[0273] [ka]

[0274] (Composition 14) The electrophotographic apparatus according to any one of configurations 1 to 13, wherein the isocyanate component constituting the urethane rubber includes at least one selected from the group consisting of isophorone diisocyanate and tolylene diisocyanate.

[0275] (Composition 15) The electrophotographic apparatus according to any one of configurations 1 to 12, wherein the developing roller has a surface layer on the elastic layer, and the surface layer contains at least one selected from the group consisting of urethane resin fine particles, acrylic resin fine particles, fluororesin fine particles, silicone resin fine particles, and silica fine particles.

[0276] (Composition 16) Electrophotographic photoreceptor, and A charging means for charging the surface of the electrophotographic photoreceptor, A contact developing means comprising toner and a developing roller, for developing an electrostatic latent image formed on the surface of an electrophotographic photoreceptor by bringing the developing roller, on which the toner is carried, into contact with the electrophotographic photoreceptor. A process cartridge characterized by integrally supporting the main body of an electrophotographic apparatus and being detachable from the main body of the electrophotographic apparatus, The electrophotographic photoreceptor has a surface layer containing a binder resin, The surface layer contains polyester resin as the binder resin, The polyester resin has structural units represented by the following formula (1) and structural units represented by the following formula (2), The developing roller has an elastic layer, A process cartridge characterized in that the elastic layer contains urethane rubber.

[0277] [ka]

[0278] [ka] [Explanation of Symbols]

[0279] 1. Single-layer photoreceptor 2. Conductive support 3 Photosensitive layer 3s single-layer photosensitive layer 4. Lower layer 5 Protective layer 10. Positively charged stacked photoreceptor 11 Charge transport layer 12 Charge generation layer 21 Developing roller 22 Axis Body 23 Elastic layer 24 Surface layer 30 Developing roller 31 Stratified blades 32 Toner supply rollers 33 Developing equipment 34 Exposure equipment 41 Charging device 42a Cleaning roller 42b Conductor 43 Pre-exposure device 44 Image Carrier Unit 45 Transfer device 50 Process cartridge frame 100 Electrophotographic devices

Claims

1. Electrophotographic photoreceptor, and A contact developing means comprising toner and a developing roller, for developing an electrostatic latent image formed on the surface of an electrophotographic photoreceptor by bringing the developing roller, on which the toner is carried, into contact with the electrophotographic photoreceptor. An electrophotographic apparatus having, The electrophotographic photoreceptor has a surface layer containing a binder resin, The surface layer contains polyester resin as the binder resin, The polyester resin has structural units represented by the following formula (1) and structural units represented by the following formula (2), The developing roller has an elastic layer, The elastic layer contains urethane rubber. An electrophotographic apparatus characterized by the following features. 【Chemistry 1】 【Chemistry 2】

2. The electrophotographic apparatus according to claim 1, wherein the polyester resin further comprises structural units represented by the following formula (4) and structural units represented by the following formula (5). 【Transformation 3】 【Chemistry 4】

3. The electrophotographic apparatus according to claim 2, wherein, in the polyester resin, when the amount of substance of the structural unit represented by formula (1) is M1 and the amount of substance of the structural unit represented by formula (4) is M4, the condition 0.30 ≤ M4 / (M1 + M4) ≤ 0.70 is satisfied.

4. The electrophotographic apparatus according to claim 2, wherein, in the polyester resin, when the amount of substance of the structural unit represented by formula (2) is M2 and the amount of substance of the structural unit represented by formula (5) is M5, the condition 0 < M2 / (M2 + M5) ≤ 0.50 is satisfied.

5. The electrophotographic photoreceptor according to claim 1, wherein when MC is the total amount of substance of the dicarboxylic acid-derived structural units constituting the polyester resin, and M1 is the amount of substance of the structural unit represented by formula (1), M1 / MC ≥ 0.

50.

6. The electrophotographic photoreceptor according to claim 1, wherein the proportion of the polyester resin to the total mass of the binder resin is 50% by mass or more.

7. The electrophotographic apparatus according to claim 1, wherein the electrophotographic photoreceptor has a single-layer photosensitive layer having a charge generating material, a hole transporting material, and an electron transporting material.

8. The electrophotographic apparatus according to claim 7, wherein the electron transport material includes at least one selected from the group consisting of a compound represented by the following formula (10), a compound represented by the following formula (11), a compound represented by the following formula (12), a compound represented by the following formula (13), a compound represented by the following formula (14), a compound represented by the following formula (15), and a compound represented by the following formula (16). 【Transformation 5】 【Transformation 6】 【Transformation 7】 【Transformation 8】 【Chemistry 9】 【Chemistry 10】 【Chemistry 11】 (Q in the formula (10) １ and Q ２ , Q in the formula (11) １１ , Q １２ , and Q １３ , Q in the formula (12) ２１ , Q ２２ , Q ２３ , and Q ２４ , Q in the formula (13) ３１ and Q ３２ , Q in the formula (14) ４１ , Q ４２ , Q ４３ , and Q ４４ , Q in the formula (15) ５１ , Q ５２ , Q ５３ , Q ５４ , Q ５５ , and Q ５６ , and Q in the formula (16) ６１ and Q ６２ each independently represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 14 carbon atoms which may be substituted with at least one substituent selected from the group consisting of an alkyl group having 1 to 6 carbon atoms and a halogen atom; Y in the formula (15) １ and Y ２ each independently represents an oxygen atom or a sulfur atom.)

9. The electrophotographic apparatus according to claim 7, wherein the electron transport material includes at least one selected from the group consisting of a compound represented by the following formula (E-1), a compound represented by the following formula (E-2), a compound represented by the following formula (E-3), a compound represented by the following formula (E-4), a compound represented by the following formula (E-5), a compound represented by the following formula (E-6), a compound represented by the following formula (E-7), and a compound represented by the following formula (E-8). 【Chemistry 12】 【Chemistry 13】 【Chemistry 14】 【Chemistry 15】 【Chemistry 16】 【Chemistry 17】 [Chemistry 18] 【Chemistry 19】

10. The electrophotographic apparatus according to claim 7, wherein the hole transport material includes at least one selected from the group consisting of a compound represented by the following formula (20), a compound represented by the following formula (21), a compound represented by the following formula (22), a compound represented by the following formula (23), and a compound represented by the following formula (24). 【Chemistry 20】 【Chemistry 21】 【Chemistry 22】 【Chemistry 23】 【Chemistry 24】 (In the above formula (20), R １１ , R １２ , R １３ , and R １４ Each independently represents an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, a １ a ２ a ３ , and a ４ Each of these independently represents an integer between 0 and 5, and in formula (21) above, R ２１ , R ２２ , and R ２３ Each of these independently represents an alkyl group having 1 to 6 carbon atoms, and R ２４ , R ２５ , and R ２６ Each of these independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and b １ , b ２ , and b ３ Each independently represents either 0 or 1, and in formula (22), R ３１ , R ３２ , and R ３３ Each of these independently represents an alkyl group having 1 to 6 carbon atoms, and R ３４ represents an alkyl group or hydrogen atom having 1 to 6 carbon atoms, d １ d ２ , and d ３ Each of these independently represents an integer between 0 and 5, and in formula (23) above, R ４１ , R ４２ , R ４３ , R ４４ , R ４５ , and R ４６ Each independently represents an alkyl group having 1 to 6 carbon atoms, or a phenyl group, R ４７ and R ４８ Each of these independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group, and e １ , e ２ , e ３ , and e ４ Each of these independently represents an integer between 0 and 5, and e ５ and e ６ Each of these independently represents an integer between 0 and 4, and e ７ and e ８ Each independently represents either 0 or 1, and in formula (24), R ５０ and R ５１ Each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group, R ５２ , R ５３ , R ５４ , R ５５ , R ５６ , R ５７ , and R ５８ Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms, and f １ and f ２ Each of these independently represents an integer between 0 and 2, and f ３ and f ４ Each of these independently represents an integer between 0 and 5 (inclusive).

11. The electrophotographic apparatus according to claim 7, wherein the hole transport material includes at least one selected from the group consisting of a compound represented by the following formula (H-1), a compound represented by the following formula (H-2), a compound represented by the following formula (H-3), a compound represented by the following formula (H-4), a compound represented by the following formula (H-5), a compound represented by the following formula (H-6), a compound represented by the following formula (H-7), a compound represented by the following formula (H-8), a compound represented by the following formula (H-9), a compound represented by the following formula (H-10), and a compound represented by the following formula (H-11). 【Chemistry 25】 【Chemistry 26】 【Chemistry 27】 【Chemistry 28】 【Chemistry 29】 【Transformation 30】 【Chemistry 31】 【Chemistry 32】 【Transformation 33】 【Transformation 34】

12. The electrophotographic apparatus according to claim 7, wherein the charge generating material includes titanylphthalocyanine.

13. The electrophotographic apparatus according to claim 7, wherein the photosensitive layer contains a compound represented by formula (30). 【Chemistry 35】

14. The electrophotographic apparatus according to claim 1, wherein the isocyanate component constituting the urethane rubber includes at least one selected from the group consisting of isophorone diisocyanate and tolylene diisocyanate.

15. The electrophotographic apparatus according to claim 1, wherein the developing roller has a surface layer on the elastic layer, and the surface layer contains at least one selected from the group consisting of urethane resin fine particles, acrylic resin fine particles, fluororesin fine particles, silicone resin fine particles, and silica fine particles.

16. Electrophotographic photoreceptor, and A charging means for charging the surface of the electrophotographic photoreceptor, A contact developing means comprising toner and a developing roller, for developing an electrostatic latent image formed on the surface of an electrophotographic photoreceptor by bringing the developing roller, on which the toner is carried, into contact with the electrophotographic photoreceptor. A process cartridge characterized by integrally supporting the main body of an electrophotographic apparatus and being detachable from the main body of the electrophotographic apparatus, The electrophotographic photoreceptor has a surface layer containing a binder resin, The surface layer contains polyester resin as the binder resin, The polyester resin has structural units represented by the following formula (1) and structural units represented by the following formula (2), The developing roller has an elastic layer, A process cartridge characterized in that the elastic layer contains urethane rubber. 【Transformation 36】 【Chemistry 37】

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