Electrophotographic photoreceptor, process cartridge, and image forming device

Abstract

The present invention relates to an electrophotographic photoreceptor, a processing box and an image forming device. The electrophotographic photoreceptor comprises a conductive substrate and a photosensitive layer provided on the conductive substrate, wherein the number of carboxyl groups contained in the fluorine-containing resin particles is 6 The number of carbon atoms is 0 or more and 30 or less, the dielectric constant of the outermost surface layer is 3.75 or more and 3.90 or less, and the pure water contact angle of the outermost surface layer is 90° or more.

Description

Technical Field

[0001] The present invention relates to an electronic photographic photoreceptor, a process cartridge and an image forming device. Background Art

[0002] Japanese Patent Gazette No. 3950559 proposes "an electronic photographic device, which is an electronic photographic device that applies imaging processing to form images, and the imaging processing includes the step of charging the surface of the charged body by using a charging processing mechanism, characterized in that the charged body is an electronic photographic photosensitive body in which a charge generating layer and a charge transport layer formed by dip coating are sequentially stacked on a conductive support, and the charge transport layer formed by dip coating is a surface layer, the surface layer contains a charge transport material, a binder resin and a silicone defoaming agent, the silicone defoaming agent is dimethylpolysiloxane, and the content of dimethylpolysiloxane in the surface layer is 0.002 to 0.01% by weight relative to the binder resin, and the charging processing mechanism of the charged body is a direct charging device that charges the surface of the charged body by bringing a charging component to which a voltage is applied into contact with the charged body."

[0003] Japanese Patent Publication No. 2000-292960 proposes "an electronic photographic photoreceptor having a photosensitive layer and a protective layer on a conductive support, characterized in that the protective layer contains conductive particles, a fluorine atom-containing compound, a siloxane compound, fluorine atom-containing resin particles and a binder resin." Summary of the invention

[0004] Technical problem to be solved by the invention

[0005] The technical problem to be solved by the present invention is to provide an electrophotographic photoreceptor, wherein the residual potential of the electrophotographic photoreceptor provided by the present invention is reduced and the generation of bubbles on the surface of the outermost surface layer is suppressed compared with the following situation: in an electrophotographic photoreceptor having a conductive substrate and a photosensitive layer provided on the conductive substrate, and the outermost surface layer containing fluorine-containing resin particles and a fluorine-containing grafted polymer, the number of carboxyl groups contained in the fluorine-containing resin particles is 10 6 The number of carbon atoms is greater than 30; the dielectric constant of the outermost surface layer is less than 3.75 or greater than 3.90; the pure water contact angle of the outermost surface layer is less than 90°; when the outermost surface layer further contains a defoaming agent, the content of the fluorine-containing grafted polymer relative to the content of the fluorine-containing resin particles is less than 4.5% by mass or greater than 9.0% by mass; or when the outermost surface layer further contains a defoaming agent, the content of the defoaming agent in the outermost surface layer is less than 10ppm or greater than 10000ppm.

[0006] Means for solving technical problems

[0007] According to a first aspect of the present invention, there is provided an electrophotographic photoreceptor, wherein:

[0008] The electrophotographic photoreceptor comprises a conductive substrate and a photosensitive layer provided on the conductive substrate.

[0009] The outermost surface layer contains fluorine-containing resin particles and fluorine-containing graft polymer,

[0010] The number of carboxyl groups contained in the fluorine-containing resin particles is relative to 10 6 The number of carbon atoms is 0 to 30.

[0011] The dielectric constant of the outermost surface layer is not less than 3.75 and not more than 3.90.

[0012] The pure water contact angle of the outermost surface layer is 90° or more.

[0013] According to a second aspect of the present invention, the dielectric constant of the outermost surface layer is not less than 3.80 and not more than 3.90, and the pure water contact angle of the outermost surface layer is not less than 95°.

[0014] According to a third aspect of the present invention, there is provided an electrophotographic photoreceptor, wherein:

[0015] The electrophotographic photoreceptor comprises a conductive substrate and a photosensitive layer provided on the conductive substrate.

[0016] The outermost surface layer contains fluorine-containing resin particles, fluorine-containing graft polymer and defoaming agent.

[0017] The number of carboxyl groups contained in the fluorine-containing resin particles is relative to 10 6 The number of carbon atoms is 0 to 30.

[0018] The content of the fluorinated graft polymer relative to the content of the fluorinated resin particles is 4.5% by mass or more and 9.0% by mass or less,

[0019] The content of the defoaming agent in the outermost surface layer is 10 ppm to 10000 ppm.

[0020] According to a fourth aspect of the present invention, the defoaming agent is at least one selected from a silicone defoaming agent and a fluorine-based defoaming agent.

[0021] According to a fifth aspect of the present invention, the defoaming agent is dimethyl polysiloxane.

[0022] According to a sixth aspect of the present invention, the content of the defoaming agent relative to the content of the fluorine-containing resin particles is 0.01 mass % to 15 mass %.

[0023] According to a seventh aspect of the present invention, the content of the defoaming agent in the outermost layer is 100 ppm to 5000 ppm.

[0024] According to an eighth aspect of the present invention, there is provided a process cartridge that is detachably mounted in an image forming apparatus and includes the electrophotographic photoreceptor described above.

[0025] According to the 9th scheme of the present invention, the above-mentioned processing box has a cleaning mechanism, which has a cleaning scraper that contacts the surface of the above-mentioned electrophotographic photosensitive body for cleaning, and the contact portion of the above-mentioned cleaning scraper that contacts the above-mentioned electrophotographic photosensitive body is composed of a component whose ratio (EIT / Re) of indentation elastic modulus (EIT[MPa]) to rebound elastic modulus (Re[%]) is greater than 0.65 and whose rebound elastic modulus (Re[%]) is greater than 25%.

[0026] According to a tenth aspect of the present invention, there is provided an image forming apparatus comprising:

[0027] The above-mentioned electrophotographic photoreceptor,

[0028] A charging mechanism is used to charge the surface of the electrophotographic photoreceptor.

[0029] The electrostatic latent image forming mechanism forms an electrostatic latent image on the charged surface of the electrophotographic photoreceptor.

[0030] a developing mechanism for developing the electrostatic latent image formed on the surface of the electrophotographic photoreceptor using a developer containing a toner to form a toner image, and

[0031] The transfer mechanism transfers the toner image onto the surface of the recording medium.

[0032] According to the 11th scheme of the present invention, the above-mentioned image forming device has a cleaning mechanism, which has a cleaning scraper that contacts the surface of the above-mentioned electrophotographic photosensitive body for cleaning, and the contact portion of the above-mentioned cleaning scraper that contacts the above-mentioned electrophotographic photosensitive body is composed of a component whose ratio (EIT / Re) of indentation elastic modulus (EIT[MPa]) to rebound elastic modulus (Re[%]) is greater than 0.65 and whose rebound elastic modulus (Re[%]) is greater than 25%.

[0033] Effects of the Invention

[0034] According to the first, second, fourth or fifth embodiment, there is provided an electrophotographic photoreceptor, wherein the number of carboxyl groups contained in the fluorine-containing resin particles per 10 6Compared with the case where the number of carbon atoms is greater than 30, the dielectric constant of the outermost layer is less than 3.80 or greater than 3.90, or the pure water contact angle of the outermost layer is less than 95°, the residual potential of the electronic photographic photoreceptor of this scheme is reduced and the generation of bubbles on the surface of the outermost layer is suppressed.

[0035] According to the third embodiment, there is provided an electrophotographic photoreceptor comprising a conductive substrate and a photosensitive layer provided on the conductive substrate, wherein the outermost surface layer of the electrophotographic photoreceptor contains fluorine-containing resin particles, a fluorine-containing graft polymer, and a defoaming agent, wherein the number of carboxyl groups contained in the fluorine-containing resin particles is 10 6 The number of carbon atoms is greater than 30; the content of the fluorine-containing grafted polymer relative to the content of the fluorine-containing resin particles is less than 4.5 mass % or greater than 9.0 mass %; or the content of the defoaming agent in the outermost surface layer is less than 10 ppm or greater than 10000 ppm, the residual potential of the electronic photographic photosensitive body of this scheme is reduced and the generation of bubbles on the surface of the outermost surface layer is suppressed.

[0036] According to the sixth embodiment, an electrophotographic photoreceptor is provided, wherein the residual potential of the electrophotographic photoreceptor is reduced and the generation of bubbles on the surface of the outermost surface layer is suppressed, compared with a case where the content of the defoaming agent relative to the content of the fluorine-containing resin particles is less than 0.01% by mass or greater than 15% by mass.

[0037] According to the seventh embodiment, an electrophotographic photoreceptor is provided, wherein the residual potential of the electrophotographic photoreceptor is reduced and the generation of bubbles on the surface of the outermost layer is suppressed, compared with the case where the content of the defoaming agent in the outermost layer is less than 100 ppm or greater than 5000 ppm.

[0038] According to the eighth or tenth embodiment, a processing box or an image forming apparatus is provided, wherein the residual potential of the electrophotographic photosensitive body provided in the processing box or the image forming apparatus is reduced, and the generation of bubbles on the outermost surface layer can be suppressed, compared with the case of providing the following comparative electrophotographic photosensitive body, wherein the comparative electrophotographic photosensitive body comprises a conductive substrate and a photosensitive layer provided on the conductive substrate, wherein the outermost surface layer comprises fluorine-containing resin particles and a fluorine-containing graft polymer, wherein the number of carboxyl groups contained in the fluorine-containing resin particles is 10 6The number of carbon atoms is greater than 30; the dielectric constant of the outermost surface layer is less than 3.75 or greater than 3.90; the pure water contact angle of the outermost surface layer is less than 90°; when the outermost surface layer further contains a defoaming agent, the content of the fluorine-containing grafted polymer relative to the content of the fluorine-containing resin particles is less than 4.5% by mass or greater than 9.0% by mass; or when the outermost surface layer further contains a defoaming agent, the content of the defoaming agent in the outermost surface layer is less than 10ppm or greater than 10000ppm.

[0039] According to the ninth or eleventh aspect, there is provided a process cartridge or an image forming apparatus, wherein the process cartridge or the image forming apparatus comprises an electrophotographic photoreceptor (the electrophotographic photoreceptor comprises a conductive substrate and a photosensitive layer provided on the conductive substrate, the outermost surface layer of which comprises fluorine-containing resin particles and a fluorine-containing graft polymer, the number of carboxyl groups contained in the fluorine-containing resin particles being 10 6 The number of carbon atoms is 0 to 30, the dielectric constant of the outermost layer is 3.75 to 3.90, and the pure water contact angle of the outermost layer is 90° or more; or the outermost layer further contains a defoaming agent, the number of carboxyl groups contained in the fluorine-containing resin particles is relative to every 10 6 In a processing box or image forming device comprising an electrophotographic photosensitive body having a carbon number of not less than 0 and not more than 30, a content of the fluorinated graft polymer relative to the content of the fluorinated resin particles is not less than 4.5 mass % and not more than 9.0 mass %, and a content of the defoaming agent in the outermost surface layer is not less than 10 ppm and not more than 10000 ppm) and a cleaning mechanism (the cleaning mechanism has a cleaning scraper which contacts the surface of the electrophotographic photosensitive body for cleaning), compared with a case where the contact portion of the cleaning scraper with the electrophotographic photosensitive body is composed of a component having a ratio (EIT / Re) of an indentation elastic modulus (EIT [MPa]) to a rebound elastic modulus (Re [%]) of less than 0.65 or a rebound elastic modulus (Re [%]) of less than 25%, the residual potential of the electrophotographic photosensitive body possessed by the processing box or image forming device of this scheme is reduced, and the generation of bubbles on the surface of the outermost surface layer is suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic cross-sectional view showing an example of the layer structure of the electrophotographic photoreceptor according to the present embodiment.

[0041] Figure 2 This is a schematic structural diagram showing an example of the image forming apparatus according to the present embodiment.

[0042] Figure 3 It is a schematic diagram showing an example of the cleaning blade in this embodiment.

[0043] Figure 4 It is a schematic diagram showing another example of the cleaning blade in this embodiment.

[0044] Figure 5 It is a schematic diagram showing another example of the cleaning blade in this embodiment.

[0045] Figure 6 This is a schematic structural diagram showing another example of the image forming apparatus according to the present embodiment. DETAILED DESCRIPTION

[0046] The following is a description of an embodiment of the present invention. These descriptions and examples are for illustrating the embodiment and do not limit the scope of the invention.

[0047] In the numerical range recorded in stages in this specification, the upper limit or lower limit recorded in one numerical range can be replaced by the upper limit or lower limit of the numerical range in other stages recorded. In addition, in the numerical range recorded in this specification, the upper limit or lower limit of the numerical range can be replaced by the value shown in the embodiment.

[0048] Each component may contain two or more corresponding substances.

[0049] When referring to the amount of each component in a composition, if there are two or more substances corresponding to each component in the composition, unless otherwise stated, it refers to the total amount of the two or more substances present in the composition.

[0050] <Electrophotographic Photoreceptor>

[0051] The electrophotographic photoreceptor (hereinafter also referred to as "photoreceptor") of the first embodiment has a conductive substrate and a photosensitive layer provided on the conductive substrate, and the outermost surface layer contains fluorine-containing resin particles and a fluorine-containing graft polymer.

[0052] In addition, the number of carboxyl groups contained in the fluorine-containing resin particles is relative to 10 6 The number of carbon atoms is 0 or more and 30 or less, the dielectric constant of the outermost surface layer is 3.75 or more and 3.90 or less, and the pure water contact angle of the outermost surface layer is 90° or more.

[0053] Since the photoreceptor of the first embodiment has the above-mentioned configuration, the residual potential is reduced and the generation of bubbles on the surface of the outermost layer is suppressed. The reason for this is presumably as follows.

[0054] In order to improve the wear resistance of the photoreceptor, a method of making the outermost surface layer of the photoreceptor contain fluorine-containing resin particles is used. 6Fluorine-containing resin particles having carboxyl groups with carbon atoms of 0 to 30 can improve the charging property of the photosensitive layer. On the other hand, it is difficult to disperse uniformly in the outermost surface layer coating liquid used for the preparation of the outermost surface layer, and it is necessary to improve the dispersibility. In addition, the fluorine-containing resin particles are included and the fluorine-containing resin particles contain 10 6 The dielectric constant of the photosensitive layer containing carboxyl groups with carbon atoms of 0 to 30 is low, and residual potential is likely to remain. In view of this, the inventors have found that by adding a large amount of fluorine-containing graft polymer as a dispersant, the dispersibility of the fluorine-containing resin particles can be improved; and by increasing the dielectric constant, the increase of residual potential can be effectively suppressed.

[0055] However, the free fluorinated graft polymer in the coating liquid acts as a surfactant, thereby increasing the foaming property of the outermost layer coating liquid and the stabilization of bubbles, and bubbles are likely to remain as defects on the surface of the outermost layer.

[0056] On the other hand, in the photoreceptor of the first embodiment, by preparing the outermost surface layer coating liquid in such a manner that the pure water contact angle of the outermost surface layer is within the above-described range, the surface tension of the outermost surface layer coating liquid can be reduced during the manufacture of the outermost surface layer of the photoreceptor, and bubbles are not easily generated. As a result, the photoreceptor of the first embodiment can suppress the generation of bubbles on the surface of the outermost surface layer. In addition, although the details are not yet clear, the outermost surface layer of the photoreceptor contains a fluorine-containing graft polymer and a carboxyl group number relative to every 10 6 When the fluorine-containing resin particles have a carbon number of 0 to 30, the dielectric constant of the outermost layer is improved. Furthermore, by adjusting the dielectric constant of the outermost layer to be within the above-described range, the residual potential of the photosensitive layer can be suppressed.

[0057] Therefore, it is presumed that the residual potential of the photoreceptor of the first embodiment is reduced, and the generation of bubbles on the surface of the outermost layer is suppressed.

[0058] The photoreceptor of the second embodiment comprises a conductive substrate and a photosensitive layer provided on the conductive substrate, wherein the outermost layer contains fluorine-containing resin particles, a fluorine-containing graft polymer and a defoaming agent.

[0059] In addition, the number of carboxyl groups contained in the fluorine-containing resin particles is relative to 10 6 The number of carbon atoms is not less than 0 and not more than 30, the content of the fluorine-containing grafted polymer relative to the content of the fluorine-containing resin particles is not less than 4.5 mass % and not more than 9.0 mass %, and the content of the defoaming agent in the outermost surface layer is not less than 10 ppm (ppm is a mass basis. The same applies hereinafter) and not less than 10000 ppm.

[0060] Since the photoreceptor of the second embodiment has the above-mentioned configuration, the residual potential is reduced and the generation of bubbles on the surface of the outermost layer is suppressed. The reason for this is presumably as follows.

[0061] As described above, when the outermost surface layer of the photosensitive layer contains fluorine-containing resin particles and the fluorine-containing resin particles contain 10 6 When the number of carbon atoms of the carboxyl groups is 0 to 30, bubbles are likely to be generated on the surface of the outermost layer of the photosensitive layer, and residual potential is likely to remain.

[0062] In the photoreceptor of the second embodiment, the outermost surface layer of the photoreceptor contains fluorine-containing resin particles and also contains a fluorine-containing grafted polymer and a defoaming agent. The outermost surface layer contains the defoaming agent at a concentration of 10 ppm to 10,000 ppm relative to the outermost surface layer. When the outermost surface layer of the photoreceptor is manufactured, the surface tension of the coating liquid of the outermost surface layer can be reduced, and bubbles are not easily generated even if the stirring force is increased. In addition, by making the concentration of the defoaming agent in the outermost surface layer within the above range, for example, the pure water contact angle of the outermost surface layer can easily reach 90° or more. As a result, the photoreceptor of the second embodiment can suppress the generation of bubbles on the surface of the outermost surface layer. In addition, although the details are not yet clear, the addition of the fluorine-containing grafted polymer to the outermost surface layer of the photoreceptor has a relative number of carboxyl groups per 10 6 The content of fluorine-containing resin particles with carbon atoms of 0 to 30, and the added concentration of the fluorine-containing grafted polymer is 4.5% to 9.0% by mass, so that, for example, the dielectric constant of the outermost surface layer can easily reach 3.75 to 3.90, which can suppress the residual potential of the photosensitive layer.

[0063] Therefore, it is presumed that the residual potential of the photoreceptor of the second embodiment is reduced and the generation of bubbles on the surface of the outermost layer is suppressed.

[0064] Next, a photoreceptor that conforms to both the first embodiment and the second embodiment (hereinafter also referred to as "the photoreceptor of the present embodiment") is described in detail. An example of the photoreceptor of the present invention is a photoreceptor that conforms to either of the first and second embodiments.

[0065] Hereinafter, the electrophotographic photoreceptor according to the present embodiment will be described with reference to the drawings.

[0066] Figure 1 The electrophotographic photoreceptor 7A shown has a structure in which an undercoat layer 1, a charge generating layer 2, and a charge transporting layer 3 are sequentially stacked on a conductive substrate 4. The charge generating layer 2 and the charge transporting layer 3 constitute a photosensitive layer 5.

[0067] It should be noted that the electrophotographic photoreceptor 7A may have a layer structure without the undercoat layer 1 .

[0068] The electrophotographic photoreceptor 7A may include a single-layer photosensitive layer integrating the functions of the charge generating layer 2 and the charge transporting layer 3. In the case of a photoreceptor including a single-layer photosensitive layer, the single-layer photosensitive layer constitutes the outermost layer.

[0069] The electrophotographic photoreceptor 7A may be a photoreceptor having a surface protective layer on the charge transport layer 3 or on the single-layer photosensitive layer. In the case of a photoreceptor having a surface protective layer, the surface protective layer constitutes the outermost surface layer.

[0070] Hereinafter, each layer of the electrophotographic photoreceptor of this embodiment will be described in detail. Note that reference numerals will be omitted in the description.

[0071] (Conductive substrate)

[0072] As the conductive substrate, for example, metal plates, metal drums, and metal strips containing metals (aluminum, copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold, platinum, etc.) or alloys (stainless steel, etc.) can be cited. In addition, as the conductive substrate, for example, conductive compounds (such as conductive polymers, indium oxide, etc.), metals (such as aluminum, palladium, gold, etc.), or papers, resin films, and strips coated, vapor-deposited, or laminated with alloys can also be cited. Here, "conductive" means that the volume resistivity is less than 10 13 Ωcm.

[0073] When an electrophotographic photoreceptor is used in a laser printer, the surface of the conductive substrate is preferably roughened to a center line average roughness Ra of 0.04 μm or more and 0.5 μm or less in order to suppress interference fringes generated when irradiating laser. It should be noted that when non-interference light is used as a light source, roughening for preventing interference fringes is not particularly necessary, but since the roughening can suppress the occurrence of defects caused by the surface unevenness of the conductive substrate, it is suitable for further extending the life.

[0074] Examples of the roughening method include wet honing in which an abrasive is suspended in water and sprayed onto the conductive substrate; centerless grinding in which the conductive substrate is pressed against a rotating grindstone and continuously ground; and anodizing.

[0075] As a method for roughening the surface, there is also a method in which, instead of roughening the surface of the conductive substrate, conductive or semiconductive powder is dispersed in a resin to form a layer on the surface of the conductive substrate, and the surface is roughened using particles dispersed in the layer.

[0076] The roughening treatment performed by anodic oxidation is a roughening treatment in which an oxide film is formed on the surface of a conductive substrate by anodizing a conductive substrate made of metal (e.g., aluminum) as an anode in an electrolyte solution. As the electrolyte solution, for example, sulfuric acid solution, oxalic acid solution, etc. can be cited. However, the porous anodic oxide film formed by anodic oxidation is chemically active in its original state, easily contaminated, and the resistance change due to the environment is also large. Therefore, it is preferred that the porous anodic oxide film is subjected to the following sealing treatment: in pressurized steam or boiling water (metal salts such as nickel may also be added), the volume expansion caused by the hydration reaction is utilized to block the micropores of the oxide film, so that it becomes a more stable hydrated oxide.

[0077] The film thickness of the anodic oxide film is preferably, for example, 0.3 μm or more and 15 μm or less. When the film thickness is within the above range, the film tends to exhibit a barrier property against injection and tends to suppress an increase in residual potential due to repeated use.

[0078] The conductive substrate may be subjected to a treatment using an acidic treatment liquid or a boehmite treatment.

[0079] The treatment based on the acidic treatment solution is implemented, for example, as follows. First, an acidic treatment solution containing phosphoric acid, chromic acid and hydrofluoric acid is prepared. The mixing ratio of phosphoric acid, chromic acid and hydrofluoric acid in the acidic treatment solution can be, for example, a range of 10 mass % to 11 mass % for phosphoric acid, a range of 3 mass % to 5 mass % for chromic acid, and a range of 0.5 mass % to 2 mass % for hydrofluoric acid, and the overall concentration of these acids can be in the range of 13.5 mass % to 18 mass %. The treatment temperature is, for example, preferably 42° C. to 48° C. The film thickness of the coating is preferably 0.3 μm to 15 μm.

[0080] The boehmite treatment is carried out, for example, by immersing in pure water at 90°C to 100°C for 5 to 60 minutes or contacting with heated steam at 90°C to 120°C for 5 to 60 minutes. The film thickness of the coating is preferably 0.1 μm to 5 μm. It can also be further anodized using an electrolyte solution with low coating solubility such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, citrate, etc.

[0081] (Base coating)

[0082] The undercoat layer is, for example, a layer containing inorganic particles and a binding resin.

[0083] Examples of inorganic particles include particles having a powder resistance (volume resistivity) of 10 2 Ωcm or more 10 11 Inorganic particles below Ωcm.

[0084] Among these, examples of the inorganic particles having the above resistance value include metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, and zirconium oxide particles, and zinc oxide particles are particularly preferred.

[0085] The specific surface area of ​​the inorganic particles based on the BET method can be, for example, 10 m 2 / g or above.

[0086] The volume average particle size of the inorganic particles can be, for example, 50 nm to 2000 nm (preferably 60 nm to 1000 nm).

[0087] The content of the inorganic particles is, for example, preferably from 10% by mass to 80% by mass, and more preferably from 40% by mass to 80% by mass, based on the binder resin.

[0088] The inorganic particles may be subjected to surface treatment. Two or more inorganic particles having different surface treatments or different particle sizes may be mixed and used.

[0089] Examples of the surface treatment agent include silane coupling agents, titanate coupling agents, aluminum coupling agents, surfactants, etc. Among them, silane coupling agents are preferred, and silane coupling agents having an amino group are more preferred.

[0090] Examples of the silane coupling agent having an amino group include, but are not limited to, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, and N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane.

[0091] Silane coupling agents can be used in combination of two or more. For example, a silane coupling agent having an amino group can be used in combination with other silane coupling agents. As other silane coupling agents, for example, vinyl trimethoxysilane, 3-methacryloxypropyl-tris(2-methoxyethoxy)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyl triacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, etc. can be cited, but are not limited to these.

[0092] The surface treatment method using the surface treatment agent may be any method as long as it is a known method, and may be either a dry method or a wet method.

[0093] The treatment amount of the surface treatment agent is preferably, for example, 0.5% by mass or more and 10% by mass or less relative to the inorganic particles.

[0094] Here, from the viewpoint of long-term stability of electrical characteristics and high carrier blocking properties, the undercoat layer may contain an electron accepting compound (acceptor compound) together with the inorganic particles.

[0095] As electron accepting compounds, for example, there can be mentioned: quinone compounds such as chloranil and bromoaniline; tetracyanoquinodimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone; oxadiazole compounds such as 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole, 2,5-bis(4-naphthyl)-1,3,4-oxadiazole, and 2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole; xanthone compounds; thiophene compounds; electron transporting substances such as diphenylquinone compounds such as 3,3',5,5'-tetra-tert-butyldiphenylquinone, and the like.

[0096] In particular, as the electron accepting compound, a compound having an anthraquinone structure is preferred. As the compound having an anthraquinone structure, for example, hydroxyanthraquinone compounds, aminoanthraquinone compounds, aminohydroxyanthraquinone compounds, etc. are preferred, and specifically, for example, anthraquinone, alizarin, quinizarin, anthraquinone, purpurin, etc. are preferred.

[0097] The electron accepting compound may be contained in the undercoat layer in a dispersed state together with the inorganic particles, or may be contained in the undercoat layer in a state of being attached to the surface of the inorganic particles.

[0098] Examples of a method for attaching the electron accepting compound to the surface of the inorganic particles include a dry method and a wet method.

[0099] The dry method is, for example, the following method: while the inorganic particles are stirred using a mixer with a large shear force, an electron accepting compound is directly added dropwise or an electron accepting compound dissolved in an organic solvent is added dropwise, and the electron accepting compound is sprayed together with dry air or nitrogen to attach the electron accepting compound to the surface of the inorganic particles. When the electron accepting compound is added dropwise or sprayed, it is preferably done at a temperature below the boiling point of the solvent. After the electron accepting compound is added dropwise or sprayed, it can be further calcined at more than 100°C. Regarding calcination, there is no particular restriction as long as the temperature and time are such that the electronic photographic properties can be obtained.

[0100] The wet method is, for example, the following method: while the inorganic particles are dispersed in a solvent by stirring, ultrasonic waves, a sand mill, an ultrafine grinder, a ball mill, etc., an electron accepting compound is added, and after stirring or dispersing, the solvent is removed so that the electron accepting compound is attached to the surface of the inorganic particles. The solvent removal method is, for example, filtering or distillation removal by distillation. After the solvent is removed, it can be further roasted at more than 100°C. Regarding roasting, there is no particular limitation as long as the temperature and time are such that the electronic photographic characteristics can be obtained. In the wet method, the water contained in the inorganic particles can be removed before the electron accepting compound is added. As examples thereof, a method of stirring and heating in a solvent and removing it at the same time and a method of removing it by azeotropy with a solvent can be cited.

[0101] The electron accepting compound may be attached before or after the inorganic particles are surface treated with a surface treatment agent, or the electron accepting compound may be attached and the surface treated with a surface treatment agent may be simultaneously performed.

[0102] The content of the electron accepting compound may be, for example, 0.01% by mass to 20% by mass, and preferably 0.01% by mass to 10% by mass, based on the inorganic particles.

[0103] Examples of the adhesive resin used in the primer layer include: acetal resins (e.g., polyvinyl butyral), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, unsaturated polyester resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-modified alkyd resins, urea resins, phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, alkyd resins, epoxy resins and other known polymer compounds; zirconium chelate compounds; titanium chelate compounds; aluminum chelate compounds; titanium alkoxide compounds; organic titanium compounds; silane coupling agents and other known materials.

[0104] Examples of the binder resin used in the primer layer include a charge transporting resin having a charge transporting group, and a conductive resin (for example, polyaniline).

[0105] Among these, the binding resin for the primer layer is preferably a resin that is insoluble in the coating solvent of the upper layer, and is particularly preferably a thermosetting resin such as urea resin, phenol resin, phenol-formaldehyde resin, melamine resin, urethane resin, unsaturated polyester resin, alkyd resin, epoxy resin, or a resin obtained by reacting at least one resin selected from the group consisting of polyamide resin, polyester resin, polyether resin, methacrylic resin, acrylic resin, polyvinyl alcohol resin, and polyvinyl acetal resin with a curing agent.

[0106] When using two or more of these adhesive resins in combination, the mixing ratio thereof is set as necessary.

[0107] The undercoat layer may contain various additives in order to improve electrical characteristics, improve environmental stability, and improve image quality.

[0108] As additives, there can be mentioned known materials such as polycyclic condensed pigments, azo pigments, etc., electron transport pigments, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, silane coupling agents, etc. As mentioned above, silane coupling agents are used for surface treatment of inorganic particles, but can also be further added to the primer layer as an additive.

[0109] Examples of the silane coupling agent as an additive include vinyltrimethoxysilane, 3-methacryloxypropyl-tri(2-methoxyethoxy)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, and 3-chloropropyltrimethoxysilane.

[0110] Examples of the zirconium chelate compound include zirconium butoxide, zirconium ethyl acetoacetate, zirconium triethanolamine, zirconium acetylacetonate butoxide, zirconium ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octanoate, zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, zirconium methacrylate butoxide, zirconium stearate butoxide, and zirconium isostearate butoxide.

[0111] Examples of the titanium chelate compound include tetraisopropyl titanate, tetra-n-butyl titanate, butyl titanate dimer, tetra(2-ethylhexyl) titanate, titanium acetylacetonate, titanium polyacetylacetonate, titanium octylene glycollate, ammonium lactate titanium, lactate titanium, ethyl lactate titanium, triethanolamine titanium, and polyhydroxystearate titanium.

[0112] Examples of the aluminum chelate compound include aluminum isopropoxide, aluminum diisopropoxide monobutoxy, aluminum butyrate, aluminum diethylacetoacetate diisopropoxide, and aluminum tris(ethylacetoacetate).

[0113] These additives may be used alone or in the form of a mixture or polycondensate of two or more compounds.

[0114] The Vickers hardness of the primer layer may be 35 or higher.

[0115] The surface roughness (ten-point average roughness) of the undercoat layer can be adjusted to 1 / (4n) to 1 / 2 of the wavelength λ of the exposure laser used (n is the refractive index of the upper layer) in order to suppress the moiré image.

[0116] In order to adjust the surface roughness, resin particles or the like may be added to the primer layer. Examples of the resin particles include silicone resin particles and cross-linked polymethyl methacrylate resin particles. In addition, in order to adjust the surface roughness, the surface of the primer layer may be ground. Examples of the grinding method include polishing, sandblasting, wet honing, grinding, and the like.

[0117] The formation of the undercoat layer is not particularly limited and can be formed by a known formation method. For example, it can be formed by forming a coating film of an undercoat layer-forming coating liquid prepared by adding the above components to a solvent, drying the coating film, and heating as necessary.

[0118] Examples of the solvent used for preparing the coating solution for forming the undercoat layer include known organic solvents such as alcohol solvents, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, ketone solvents, ketone alcohol solvents, ether solvents, and ester solvents.

[0119] Specific examples of these solvents include common organic solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, dichloromethane, chloroform, chlorobenzene, and toluene.

[0120] Examples of the method for dispersing the inorganic particles when preparing the coating liquid for forming an undercoat layer include known methods such as a roll mill, a ball mill, a vibration ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker.

[0121] Examples of a method for applying the coating liquid for forming an undercoat layer onto a conductive substrate include common methods such as blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0122] The film thickness of the primer layer is set, for example, preferably within the range of 15 μm or more, and more preferably within the range of 20 μm or more and 50 μm or less.

[0123] (Middle layer)

[0124] Although illustration is omitted, an intermediate layer may be further provided between the undercoat layer and the photosensitive layer.

[0125] The intermediate layer is, for example, a layer containing a resin. Examples of the resin used for the intermediate layer include acetal resins (e.g., polyvinyl butyral), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-modified alkyd resins, phenol-formaldehyde resins, melamine resins and other polymer compounds.

[0126] The intermediate layer may be a layer containing an organic metal compound. Examples of the organic metal compound used for the intermediate layer include organic metal compounds containing metal atoms such as zirconium, titanium, aluminum, manganese, and silicon.

[0127] These compounds for the intermediate layer may be used alone, or may be used in the form of a mixture or a polycondensate of two or more compounds.

[0128] Among these, the intermediate layer is preferably a layer containing an organic metal compound containing a zirconium atom or a silicon atom.

[0129] The formation of the intermediate layer is not particularly limited and can be performed by a known formation method, for example, by forming a coating film of an intermediate layer-forming coating liquid prepared by adding the above components to a solvent, drying the coating film, and heating as necessary to form the intermediate layer.

[0130] As a coating method for forming the intermediate layer, a common method such as a dip coating method, an extrusion coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, a curtain coating method, etc. is used.

[0131] The film thickness of the intermediate layer is preferably set within a range of, for example, 0.1 μm or more and 3 μm or less. In addition, the intermediate layer may be used as a primer layer.

[0132] (Charge Generation Layer)

[0133] The charge generating layer is, for example, a layer containing a charge generating material and a binder resin. In addition, the charge generating layer may be a vapor-deposited layer of the charge generating material. The vapor-deposited layer of the charge generating material is suitable for the case where a non-interference light source such as an LED (Light Emitting Diode) or an organic EL (Electro-Luminescence) image array is used.

[0134] Examples of the charge generating material include azo pigments such as disazo and trisazo; condensed ring aromatic pigments such as dibromoanthanthrone; perylene pigments; pyrrolopyrrole pigments; phthalocyanine pigments; zinc oxide; and trigonal selenium.

[0135] Among these, in order to cope with laser exposure in the near-infrared region, metal phthalocyanine pigments or metal-free phthalocyanine pigments are preferably used as charge generating materials. Specifically, for example, hydroxygallium phthalocyanine disclosed in Japanese Patent Publication No. 5-263007, Japanese Patent Publication No. 5-279591, etc.; chlorogallium phthalocyanine disclosed in Japanese Patent Publication No. 5-98181, etc.; dichlorotin phthalocyanine disclosed in Japanese Patent Publication No. 5-140472, Japanese Patent Publication No. 5-140473, etc.; titanyl phthalocyanine disclosed in Japanese Patent Publication No. 4-189873, etc. are more preferred.

[0136] On the other hand, in order to cope with laser exposure in the near-ultraviolet region, preferred charge generating materials include condensed-ring aromatic pigments such as dibromoantanthrone; thioindigo pigments; tetraazaporphyrin compounds; zinc oxide; trigonal selenium; and disazo pigments disclosed in Japanese Patent Publication No. 2004-78147 and Japanese Patent Publication No. 2005-181992.

[0137] When using a non-interference light source such as an LED or an organic EL image array having a central wavelength of light emission between 450 nm and 780 nm, the above-mentioned charge generating material can also be used. However, from the aspect of resolution, when a photosensitive layer is used as a thin film of less than 20 μm, the electric field intensity in the photosensitive layer increases, and it is easy to generate a charge reduction due to the injection of charges from the substrate, that is, to generate image defects called so-called black spots. This situation becomes significant when using a charge generating material that easily generates dark current in a p-type semiconductor, such as trigonal selenium and phthalocyanine pigments.

[0138] In contrast, when an n-type semiconductor such as a condensed aromatic pigment, perylene pigment, or azo pigment is used as a charge generating material, dark current is less likely to be generated, and image defects called black spots can be suppressed even when formed into a thin film. Examples of n-type charge generating materials include compounds (CG-1) to (CG-27) described in paragraphs

[0288] to

[0291] of Japanese Patent Application Laid-Open No. 2012-155282, but are not limited thereto.

[0139] The n-type was determined by using the polarity of the photocurrent flowing using the commonly used time-of-flight method, and the type in which electrons flow more easily as carriers than holes was determined as the n-type.

[0140] The binder resin used in the charge generating layer can be selected from a wide range of insulating resins. Alternatively, the binder resin can be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, and polysilane.

[0141] Examples of the adhesive resin include polyvinyl butyral resin, polyarylate resin (condensation product of bisphenol and aromatic divalent carboxylic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin, polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, etc. Here, "insulating property" means that the volume resistivity is 10 13 Ωcm or more.

[0142] These adhesive resins may be used alone or in combination of two or more.

[0143] It should be noted that the mixing ratio of the charge generating material to the binder resin is preferably within a range of 10:1 to 1:10 in terms of mass ratio.

[0144] The charge generating layer may further contain other known additives.

[0145] The formation of the charge generating layer is not particularly limited, and a known formation method can be used. For example, it can be performed as follows: a coating film of a coating liquid for forming a charge generating layer is formed by adding the above-mentioned components to a solvent, the coating film is dried, and the charge generating layer is formed by heating as needed. It should be noted that the formation of the charge generating layer can also be performed by vapor deposition of the charge generating material. The vapor deposition formation of the charge generating layer is particularly suitable for the case where a condensed aromatic pigment or a perylene pigment is used as the charge generating material.

[0146] Examples of the solvent used for preparing the charge generating layer-forming coating solution include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, dichloromethane, chloroform, chlorobenzene, toluene, etc. These solvents may be used alone or in combination of two or more.

[0147] As a method for dispersing particles (e.g., charge generating materials) in a coating liquid for forming a charge generating layer, for example, a medium disperser such as a ball mill, a vibrating ball mill, an ultrafine grinder, a sand mill, a horizontal sand mill, etc.; a medium-free disperser such as a stirring, ultrasonic disperser, a roller mill, a high-pressure homogenizer, etc. As a high-pressure homogenizer, for example, a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision under high pressure; a penetration method in which the dispersion liquid is dispersed by penetrating through a fine flow path under high pressure, etc. can be cited.

[0148] In the dispersion, it is effective that the average particle size of the charge generating material in the charge generating layer forming coating liquid is 0.5 μm or less, preferably 0.3 μm or less, and more preferably 0.15 μm or less.

[0149] Examples of a method for applying the coating liquid for forming a charge generating layer onto the undercoat layer (or the intermediate layer) include common methods such as blade coating, wire rod coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0150] The film thickness of the charge generating layer is set, for example, preferably within the range of 0.1 μm to 5.0 μm, more preferably within the range of 0.2 μm to 2.0 μm.

[0151] (Charge Transport Layer)

[0152] The charge transport layer is, for example, a layer containing a charge transport material and a binder resin. The charge transport layer may also be a layer containing a polymer charge transport material.

[0153] When the charge transport layer is the outermost surface layer, the charge transport layer contains fluorine-containing resin particles, a fluorine-containing graft polymer, and a defoaming agent in addition to the binder resin and the charge transport material.

[0154] It should be noted that, when other layers (such as a protective layer, etc.) are provided on the charge transport layer and the charge transport layer is not the outermost surface layer, the charge transport layer may contain at least a binding resin and a charge transport material, and may contain other additives as required. The binding resin, charge transport material and other additives are the same as when the charge transport layer is the outermost surface layer.

[0155] Next, components contained in the charge transport layer as the outermost layer will be described.

[0156] - Adhesive resin -

[0157] The adhesive resin used in the charge transport layer can be polycarbonate resin, polyester resin, polyarylate resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-modified alkyd resin, phenol-formaldehyde resin, styrene-modified alkyd resin, poly-N-vinyl carbazole, polysilane, etc. Among these, as the adhesive resin, polycarbonate resin or polyarylate resin is preferred. These adhesive resins are used alone or in two or more.

[0158] It should be noted that the mixing ratio of the charge transport material to the binder resin is preferably 10:1 to 1:5 in terms of mass ratio.

[0159] Here, the content of the binder resin is preferably 10% by mass to 90% by mass, more preferably 30% by mass to 90% by mass, and further preferably 50% by mass to 90% by mass, relative to the total solid content of the photosensitive layer (charge transport layer).

[0160] - Charge transport materials -

[0161] As charge transport materials, there can be cited quinone compounds such as para-benzoquinone, chloranil, bromoquinone, anthraquinone, etc.; tetracyanoquinodimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone; xanthone compounds; benzophenone compounds; cyanovinyl compounds; vinyl compounds and other electron transport compounds. As charge transport materials, there can also be cited hole transport compounds such as triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted vinyl compounds, isophenylethylene compounds, anthracene compounds, hydrazone compounds, etc. These charge transport materials can be used alone or in combination of two or more, but are not limited to these.

[0162] As the charge transport material, from the viewpoint of charge mobility, a triarylamine derivative represented by the following structural formula (a-1) and a benzidine derivative represented by the following structural formula (a-2) are preferred.

[0163] [Chemistry 1]

[0164]

[0165] In the structural formula (a-1), Ar T1,Ar T2 and Ar T3 each independently represents a substituted or unsubstituted aryl group, -C 6 H 4 -C(R T4 )=C(R T5 )(R T6 ) or -C 6 H 4 -CH=CH-CH=C(R T7 )(R T8 ). T4 , R T5 , R T6 , R T7 , and R T8 Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group.

[0166] Examples of the substituents of the above groups include halogen atoms, alkyl groups having 1 to 5 carbon atoms, and alkoxy groups having 1 to 5 carbon atoms. Examples of the substituents of the above groups include substituted amino groups substituted with alkyl groups having 1 to 3 carbon atoms.

[0167] [Chemistry 2]

[0168]

[0169] In the structural formula (a-2), R T91 and R T92 Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. T101 , R T102 , R T111 and R T112 Each independently represents a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an amino group substituted by an alkyl group having 1 to 2 carbon atoms, a substituted or unsubstituted aryl group, -C(R T12 )=C(R T13 )(R T14 ) or -CH=CH-CH=C(R T15 )(R T16 ), R T12 , R T13 , R T14 , R T15 and R T16 Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Tm1, Tm2, ​​Tn1, and Tn2 each independently represent an integer of 0 or more and 2 or less.

[0170] Examples of the substituents of the above groups include halogen atoms, alkyl groups having 1 to 5 carbon atoms, and alkoxy groups having 1 to 5 carbon atoms. Examples of the substituents of the above groups include substituted amino groups substituted with alkyl groups having 1 to 3 carbon atoms.

[0171] Among the triarylamine derivatives represented by the structural formula (a-1) and the benzidine derivatives represented by the structural formula (a-2), those having “—C 6 H 4 -CH=CH-CH=C(R T7 )(R T8 )" and triarylamine derivatives having "-CH=CH-CH=C(R T15 )(R T16 )" benzidine derivatives.

[0172] As the polymer charge transport material, known materials having charge transport properties such as poly-N-vinyl carbazole and polysilane are used. In particular, polyester-based polymer charge transport materials disclosed in Japanese Patent Publication No. 8-176293 and Japanese Patent Publication No. 8-208820 are particularly preferred. It should be noted that the polymer charge transport material can be used alone or in combination with a binding resin.

[0173] - Fluorine-containing resin particles -

[0174] Examples of the fluorine-containing resin particles include particles of homopolymers of fluoroolefins and particles of copolymers of two or more fluoroolefins and a non-fluorine-containing monomer (ie, a monomer having no fluorine atom).

[0175] Examples of the fluoroolefin include perhaloolefins such as tetrafluoroethylene (TFE), perfluorovinyl ether, hexafluoropropylene (HFP), and chlorotrifluoroethylene (CTFE), and non-perfluoroolefins such as vinylidene fluoride (VdF), trifluoroethylene, and vinyl fluoride. Among these, VdF, TFE, CTFE, and HFP are preferred.

[0176] On the other hand, as non-fluorine-based monomers, for example, hydrocarbon olefins such as ethylene, propylene, and butene can be cited; alkyl vinyl ethers such as cyclohexyl vinyl ether (CHVE), ethyl vinyl ether (EVE), butyl vinyl ether, and methyl vinyl ether; alkenyl vinyl ethers such as polyoxyethylene allyl ether (POEAE) and ethyl allyl ether; organic silicon compounds having reactive α,β-unsaturated groups such as vinyl trimethoxysilane (VSi), vinyl triethoxysilane, and vinyl tri(methoxyethoxy)silane; acrylic esters such as methyl acrylate and ethyl acrylate; methacrylic esters such as methyl methacrylate and ethyl methacrylate; vinyl esters such as vinyl acetate, vinyl benzoate, and "VeoVA" (trade name, vinyl ester manufactured by Shell); etc. Among these, alkyl vinyl ethers, allyl vinyl ethers, vinyl esters, and organic silicon compounds having reactive α,β-unsaturated groups are preferred.

[0177] Among these, as fluorine-containing resin particles, particles with a high fluorination rate are preferred, and particles of polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (PFA), ethylene-tetrafluoroethylene copolymer (ETFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE) and the like are more preferred, and particles of PTFE, FEP, and PFA are particularly preferred.

[0178] In the fluorine-containing resin particles, every 10 6 The number of carboxyl groups is 0 or more and 30 or less per carbon atom.

[0179] When the number of carboxyl groups in the fluorine-containing resin particles is within the above range, the charging performance can be improved.

[0180] The number of carboxyl groups in the fluorine-containing resin particles is preferably 0 to 20 from the viewpoint of improving charging properties.

[0181] Here, the carboxyl group of the fluorine-containing resin particles is, for example, a carboxyl group derived from a terminal carboxylic acid contained in the fluorine-containing resin particles.

[0182] Examples of methods for reducing the carboxyl group content of the fluorine-containing resin particles include: 1) not irradiating the particles during the particle production process; and 2) irradiating the particles in the absence of oxygen or at a reduced oxygen concentration.

[0183] The carboxyl group content of the fluorine-containing resin particles is measured as follows according to the description in Japanese Unexamined Patent Application Publication No. 4-20507.

[0184] The fluorine-containing resin particles were preformed using a press to produce a film with a thickness of about 0.1 mm. The produced film was subjected to infrared absorption spectrum measurement. The fluorine-containing resin particles whose carboxylic acid terminals were completely fluorinated by contacting fluorine gas with the fluorine-containing resin particles were also subjected to infrared absorption spectrum measurement. The number of terminal carboxyl groups (per 10 6 number of carbon atoms) = (l×K) / t

[0185] l: absorbance

[0186] K: Correction coefficient

[0187] t: film thickness (mm)

[0188] The absorption wave number of carboxyl group is 3560cm -1 , the correction factor is 440.

[0189] Here, the fluorine-containing resin particles include particles obtained by irradiation with radiation (also referred to as "radiation-irradiated fluorine-containing resin particles" in this specification) and particles obtained by polymerization (also referred to as "polymerized fluorine-containing resin particles" in this specification).

[0190] The radiation-irradiated fluororesin particles (fluororesin particles obtained by irradiation) are fluororesin particles obtained by granulation by radiation polymerization, or fluororesin particles obtained by reducing the molecular weight and micronizing the polymerized fluororesin by decomposition by radiation irradiation.

[0191] The radiation-irradiated fluorine-containing resin particles generate a large amount of carboxylic acid by irradiation with radiation in the air, and therefore also contain a large amount of carboxyl groups.

[0192] On the other hand, polymerizable fluorine-containing resin particles (fluorine-containing resin particles obtained by a polymerization method) refer to fluorine-containing resin particles which are granulated while being polymerized by a suspension polymerization method, an emulsion polymerization method or the like and which are not irradiated with radiation.

[0193] The fluorine-containing resin particles may be polymerizable fluorine-containing resin particles. As described above, the polymerizable fluorine-containing resin particles are granulated while being polymerized by suspension polymerization, emulsion polymerization, or the like and are not irradiated with radiation.

[0194] Here, the production of fluorine-containing resin particles by suspension polymerization is, for example, a method in which monomers for forming fluorine-containing resins are suspended in a dispersion medium together with additives such as a polymerization initiator and a catalyst, and the polymer is granulated while polymerizing the monomers.

[0195] The production of fluorine-containing resin particles by emulsion polymerization is, for example, a method in which monomers for forming fluorine-containing resins are emulsified together with additives such as polymerization initiators and catalysts in a dispersion medium using a surfactant (i.e., an emulsifier), and then the polymer is granulated while the monomers are polymerized.

[0196] In particular, the fluorine-containing resin particles may be particles obtained without irradiation with radiation in the production step.

[0197] Among them, the fluororesin particles may be radiation-irradiated fluororesin particles obtained by irradiating with radiation in the absence of oxygen or under conditions where the oxygen concentration is reduced.

[0198] The average particle size of the fluorine-containing resin particles is not particularly limited, but is preferably 0.2 μm or more and 4.5 μm or less, and more preferably 0.2 μm or more and 4 μm or less.

[0199] The average particle size of the fluorine-containing resin particles is a value measured by the following method.

[0200] The maximum diameter of the fluorine-containing resin particles (secondary particles formed by agglomeration of primary particles) is measured by SEM (scanning electron microscope) at a magnification of 5000 or more, and the measurement is performed on 50 particles and the average value obtained is used as the average particle size of the fluorine-containing resin particles. It should be noted that JSM-6700F manufactured by JEOL Ltd. is used as SEM, and secondary electron images with an acceleration voltage of 5 kV are observed.

[0201] From the viewpoint of dispersion stability, the specific surface area (BET specific surface area) of the fluorine-containing resin particles is preferably 5 m 2 / g above 15m 2 / g or less, more preferably 7m 2 / g above 13m 2 / g or less.

[0202] In addition, the specific surface area is a value measured by the nitrogen replacement method using a BET type specific surface area measuring instrument (manufactured by Shimadzu Corporation: FlowsoapII2300).

[0203] From the viewpoint of dispersion stability, the apparent density of the fluorine-containing resin particles is preferably from 0.2 g / ml to 0.5 g / ml, more preferably from 0.3 g / ml to 0.45 g / ml.

[0204] In addition, the apparent density is a value measured according to JIS K6891 (1995).

[0205] The melting temperature of the fluorine-containing resin particles is preferably 300°C or higher and 340°C or lower, more preferably 325°C or higher and 335°C or lower.

[0206] In addition, the melting temperature is a melting point measured according to JIS K6891 (1995).

[0207] The content of the fluorine-containing resin particles is preferably 1% by mass to 20% by mass, more preferably 5% by mass to 15% by mass, further preferably 7% by mass to 10% by mass, based on the outermost surface layer.

[0208] - Fluorinated Graft Polymers -

[0209] Fluorinated graft polymers are dispersants containing fluorine.

[0210] Examples of the fluorine-containing graft polymer include polymers obtained by homopolymerizing or copolymerizing a polymerizable compound having a fluorinated alkyl group (hereinafter also referred to as "fluorinated alkyl group-containing polymer").

[0211] Specific examples of the fluorinated graft polymer include homopolymers of (meth)acrylates having a fluoroalkyl group, and random or block copolymers of (meth)acrylates having a fluoroalkyl group and a monomer having no fluorine atom. (Meth)acrylates refer to both acrylates and methacrylates.

[0212] Examples of the (meth)acrylate having a fluoroalkyl group include 2,2,2-trifluoroethyl (meth)acrylate and 2,2,3,3,3-pentafluoropropyl (meth)acrylate.

[0213] Examples of the monomer not having a fluorine atom include (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, isooctyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, 2-ethoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and (meth)acrylate. Benzyl ester, ethyl carbitol (meth)acrylate, phenoxyethyl (meth)acrylate, 2-hydroxy (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, hydroxyethyl o-phenylphenol (meth)acrylate, o-phenylphenol glycidyl ether (meth)acrylate.

[0214] In addition, specific examples of the fluorine-containing graft polymer include block or branched polymers disclosed in US Pat. No. 5,637,142 and Japanese Patent No. 4,251,662. Furthermore, specific examples of the fluorine-containing graft polymer include fluorine-based surfactants.

[0215] Among these, the fluorinated graft polymer is preferably a fluorinated alkyl group-containing polymer having a structural unit represented by the following general formula (FA), and more preferably a fluorinated alkyl group-containing polymer having a structural unit represented by the following general formula (FA) and a structural unit represented by the following general formula (FB).

[0216] Next, a fluorinated alkyl group-containing polymer having a structural unit represented by the following general formula (FA) and a structural unit represented by the following general formula (FB) will be described.

[0217] [Chemistry 3]

[0218]

[0219] In the general formulas (FA) and (FB), R F1 , R F2 , R F3 and R F4 Each independently represents a hydrogen atom or an alkyl group.

[0220] X F1 It represents an alkylene chain, a halogen-substituted alkylene chain, -S-, -O-, -NH- or a single bond.

[0221] Y F1 represents an alkylene chain, a halogen-substituted alkylene chain, -(C fx H 2fx-1 (OH))- or single bond.

[0222] Q F1 It represents -O- or -NH-.

[0223] fl, fm and fn each independently represent an integer of 1 or more.

[0224] fp, fq, fr and fs each independently represent an integer of 0 or 1 or more.

[0225] ft represents an integer of 1-7.

[0226] fx represents an integer greater than or equal to 1.

[0227] In the general formulas (FA) and (FB), as R F1 , R F2 , R F3 and R F4The group is preferably a hydrogen atom, a methyl group, an ethyl group, a propyl group, etc., more preferably a hydrogen atom, a methyl group, and further preferably a methyl group.

[0228] In the general formulas (FA) and (FB), as X F1 and Y F1 The alkylene chain (unsubstituted alkylene chain, halogen-substituted alkylene chain) is preferably a linear or branched alkylene chain having 1 to 10 carbon atoms.

[0229] Represents Y F1 -(C fx H 2fx-1 It is preferred that fx in (OH)- represents an integer of 1-10.

[0230] It is preferred that fp, fq, fr and fs each independently represent 0 or an integer of 1 to 10.

[0231] For example, fn is preferably 1 to 60.

[0232] Here, in the fluorinated graft polymer, the ratio of the structural unit represented by the general formula (FA) to the structural unit represented by the general formula (FB), i.e., fl:fm, is preferably in the range of 1:9 to 9:1, more preferably in the range of 3:7 to 7:3.

[0233] The fluorinated graft polymer may further contain a structural unit represented by the general formula (FC) in addition to the structural unit represented by the general formula (FA) and the structural unit represented by the general formula (FB). The content ratio of the structural unit represented by the general formula (FC) is preferably in the range of 10:0 to 7:3, more preferably in the range of 9:1 to 7:3, as measured by the ratio (fl+fm:fz) to the total content of the structural units represented by the general formulas (FA) and (FB) (i.e., fl+fm).

[0234] [Chemistry 4]

[0235]

[0236] In the general formula (FC), R F5 and R F6 Each independently represents a hydrogen atom or an alkyl group. fz represents an integer of 1 or greater.

[0237] In the general formula (FC), as R F5 and R F6 The group is preferably a hydrogen atom, a methyl group, an ethyl group, a propyl group, etc., more preferably a hydrogen atom, a methyl group, and further preferably a methyl group.

[0238] Examples of commercially available fluorinated graft polymers include GF300 and GF400 (manufactured by Toagosei Co., Ltd.), Surflon series (manufactured by AGC Seimi Chemical Co., Ltd.), Ftergent series (manufactured by NOES Co., Ltd.), PF series (manufactured by Kitamura Chemical Co., Ltd.), MEGAFACE series (manufactured by DIC), and FC series (manufactured by 3M).

[0239] The weight average molecular weight Mw of the fluorinated graft polymer is preferably from 20,000 to 200,000, more preferably from 50,000 to 200,000, from the viewpoint of improving the dispersibility of the fluorinated resin particles.

[0240] The weight average molecular weight of the fluorinated graft polymer is a value measured by gel permeation chromatography (GPC). For molecular weight measurement by GPC, for example, a GPC HLC-8120 manufactured by Tosoh is used as a measuring apparatus, a TSKgel GMHHR-M + TSKgel GMHHR-M (7.8 mmI.D. 30 cm) manufactured by Tosoh is used as a column, and a chloroform solvent is used for measurement, and a molecular weight calibration curve prepared using a monodisperse polystyrene standard sample is used for calculation based on the measurement result.

[0241] The content of the fluorine-containing graft polymer is 4.5% by mass or more and 9.0% by mass or less based on the content of the fluorine-containing resin particles.

[0242] When the content of the fluorine-containing graft polymer is within the above range, the dielectric constant of the photosensitive layer can be increased.

[0243] From the viewpoint of increasing the dielectric constant of the photosensitive layer, the content of the fluorine-containing graft polymer is preferably at least 5 mass % and at most 6 mass % based on the content of the fluorine-containing resin particles.

[0244] It should be noted that the fluorine-containing graft polymer may be used alone or in combination of two or more.

[0245] -Defoaming agent-

[0246] Examples of the defoaming agent include silicone defoaming agents, fluorine defoaming agents, polyether defoaming agents, fatty acid ester defoaming agents, etc. These may be used alone or in combination of two or more.

[0247] Examples of the silicone-based antifoaming agent include dimethyl silicone, methyl hydrogen silicone, and organic modified silicone.

[0248] Examples of the fluorine-based defoaming agent include fluorine-modified silicone (fluorosilicone), perfluoropolyether, perfluoroalkylsulfonate, perfluoroalkylcarboxylate, perfluoroalkylphosphate, perfluoroalkylbetaine, and perfluoroalkylamine oxide compounds.

[0249] Examples of the polyether-based defoaming agent include polyoxyalkylene glycol monoalkyl (or alkenyl) ethers obtained by adding ethylene oxide or propylene oxide to an aliphatic alcohol having 16 to 20 carbon atoms.

[0250] Examples of the fatty acid ester antifoaming agent include glyceryl monoricinoleate, alkenyl succinic acid derivatives, sorbitan monolaurate, and sorbitan trioleate.

[0251] The defoaming agent is preferably at least one selected from dimethyl polysiloxane and a fluorine-based defoaming agent, and more preferably dimethyl polysiloxane, from the viewpoint of suppressing the generation of bubbles on the surface of the outermost layer.

[0252] The content of the defoaming agent in the outermost surface layer is 10 ppm to 10000 ppm.

[0253] When the content of the defoaming agent in the outermost layer is 10 ppm to 10000 ppm, the surface tension of the outermost layer coating liquid can be reduced during the production of the outermost layer, and bubbles are less likely to be generated.

[0254] From the viewpoint of suppressing the generation of bubbles on the surface of the outermost layer, the content of the defoaming agent relative to the outermost layer is preferably from 10 ppm to 5000 ppm, and more preferably from 100 ppm to 5000 ppm.

[0255] From the viewpoint of suppressing the generation of bubbles on the surface of the outermost layer, the content of the defoaming agent relative to the content of the fluorine-containing resin particles is preferably from 0.01 mass % to 15 mass %, more preferably from 0.01 mass % to 10 mass %.

[0256] - Dielectric constant of the outermost surface layer -

[0257] In the photoreceptor of the present embodiment, the dielectric constant of the outermost layer is 3.75 or more and 3.90 or less.

[0258] By setting the dielectric constant of the outermost layer to be 3.75 or more and 3.90 or less, the dielectric constant of the photosensitive layer is improved, and the residual potential can be suppressed from remaining.

[0259] In order to make the dielectric constant of the outermost surface layer within the above range, the content of the fluorinated graft polymer is preferably 4.5 mass % or more and 9.0 mass % or less based on the content of the fluorinated resin particles.

[0260] From the viewpoint of increasing the dielectric constant of the photosensitive layer and suppressing the residual potential from remaining, the dielectric constant of the outermost layer is preferably 3.77 to 3.90, more preferably 3.80 to 3.90.

[0261] The measurement of the dielectric constant of the outermost surface layer will be described.

[0262] A plate-shaped sample was collected from the target layer of the electrophotographic photosensitive body. The plate-shaped sample was clamped between a gold electrode and an aluminum plate to make a cell. For this cell, an alternating current resistance was applied using an Impedance Analyzer manufactured by SOLARTRON, and the electrostatic capacitance was measured to calculate the dielectric constant. The measurement conditions are as follows.

[0263] ·Measurement frequency range: 1000000Hz~0.001Hz

[0264] Bias voltage: 0V

[0265] Applied peak AC electric field: 0.2V / μm

[0266] ·Measurement environment: 30℃, 85%RH

[0267] -Pure water contact angle of the outermost surface layer-

[0268] In the photoreceptor of the present embodiment, the pure water contact angle of the outermost surface layer is 90° or more.

[0269] By preparing the outermost layer coating solution so that the pure water contact angle of the outermost layer is 90° or more, the surface tension of the outermost layer coating solution can be reduced during the production of the outermost layer of the photoreceptor, and bubbles are less likely to be generated in the outermost layer.

[0270] In order to make the pure water contact angle of the outermost surface layer within the above range, the content of the defoaming agent contained in the outermost surface layer is preferably set to 10 ppm or more and 10000 ppm or less.

[0271] From the viewpoint of suppressing the generation of bubbles on the surface of the outermost layer, the pure water contact angle of the outermost layer is preferably 95° to 120°, more preferably 100° to 110°.

[0272] In the measurement of the pure water contact angle of the outermost surface layer, a contact angle meter (CA-X, manufactured by Kyowa Interface Chemical Co., Ltd.) was used to add 3.1 μl of pure water to the horizontally placed outermost surface layer at a temperature of 25°C and a humidity of 50%. The droplets were photographed using an optical microscope 15 seconds after the addition, and the contact angle θ of the pure water was calculated based on the photograph.

[0273] The charge transport layer may contain other known additives.

[0274] The charge transport layer can be formed by any known method without particular limitation. For example, the charge transport layer can be formed by forming a coating film of a charge transport layer-forming coating liquid prepared by adding the above components to a solvent, drying the coating film, and heating as necessary.

[0275] As the solvent for preparing the coating solution for forming the charge transport layer, there can be mentioned aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene; ketones such as acetone and 2-butanone; halogenated aliphatic hydrocarbons such as dichloromethane, chloroform, and vinyl chloride; cyclic or linear ethers such as tetrahydrofuran and diethyl ether, and other common organic solvents. These solvents can be used alone or in combination of two or more.

[0276] Examples of a coating method for coating the charge transport layer-forming coating liquid on the charge generating layer include common methods such as blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0277] The film thickness of the charge transport layer is set, for example, preferably within the range of 5 μm to 50 μm, more preferably within the range of 10 μm to 30 μm.

[0278] (Protective layer)

[0279] The protective layer is provided on the photosensitive layer as required. The protective layer is provided, for example, to prevent chemical changes in the photosensitive layer during charging or to further improve the mechanical strength of the photosensitive layer.

[0280] Therefore, the protective layer may be a layer composed of a cured film (crosslinked film). Examples of these layers include the layers described in the following 1) or 2).

[0281] 1) A layer consisting of a cured film of a composition comprising a reactive group-containing charge transport material having a reactive group and a charge transport skeleton in the same molecule (i.e., a layer comprising a polymer or a crosslinked body of the reactive group-containing charge transport material)

[0282] 2) A layer composed of a cured film of a composition comprising a non-reactive charge transport material and a reactive group-containing non-charge transport material having no charge transport skeleton but having a reactive group (i.e., a layer comprising a non-reactive charge transport material and a polymer or a crosslinked body of the reactive group-containing non-charge transport material)

[0283] Examples of the reactive group of the reactive group-containing charge transport material include chain polymerizable groups, epoxy groups, -OH, -OR [wherein R represents an alkyl group], -NH 2 、-SH、-COOH、-SiR Q1 3-Qn (OR Q2 ) Qn [Among them, R Q1 represents a hydrogen atom, an alkyl group, or a substituted or unsubstituted aryl group, R Q2represents a hydrogen atom, an alkyl group, a trialkylsilyl group, Qn represents an integer of 1 to 3] and the like.

[0284] As the chain polymerizable group, there is no particular limitation as long as it is a functional group that can be subjected to free radical polymerization, and for example, it is a functional group having a group containing at least a carbon double bond. Specifically, there can be mentioned a group containing at least one selected from a vinyl group, a vinyl ether group, a vinyl sulfide group, a styryl group (vinyl phenyl group), an acryloyl group, a methacryloyl group, and derivatives thereof. Among them, for the reason of its excellent reactivity, as the chain polymerizable group, it is preferably a group containing at least one selected from a vinyl group, a styryl group (vinyl phenyl group), an acryloyl group, a methacryloyl group, and derivatives thereof.

[0285] The charge transport skeleton of the reactive group-containing charge transport material is not particularly limited as long as it is a known structure in an electrophotographic photoreceptor, and for example, the following structure can be cited: the skeleton of the structure is derived from a nitrogen-containing hole transport compound such as a triarylamine compound, a benzidine compound, a hydrazone compound, and is conjugated with a nitrogen atom. Among these, a triarylamine skeleton is preferred.

[0286] The reactive group-containing charge transport material, non-reactive charge transport material, and reactive group-containing non-charge transport material having a reactive group and a charge transport skeleton may be selected from known materials.

[0287] The protective layer may contain other known additives.

[0288] The protective layer can be formed by any known method without particular limitation. For example, the protective layer can be formed by forming a coating film of a protective layer-forming coating liquid prepared by adding the above components to a solvent, drying the coating film, and performing a curing treatment such as heating as required.

[0289] Examples of the solvent used to prepare the protective layer-forming coating solution include aromatic solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; ether solvents such as tetrahydrofuran and dioxane; cellosolve solvents such as ethylene glycol monomethyl ether; alcohol solvents such as isopropyl alcohol and butanol, etc. These solvents may be used alone or in combination of two or more.

[0290] In addition, the coating liquid for forming a protective layer may be a solvent-free coating liquid.

[0291] Examples of a method for applying the protective layer-forming coating liquid onto a photosensitive layer (e.g., a charge transport layer) include common methods such as dip coating, extrusion coating, wire rod coating, spray coating, blade coating, knife coating, and curtain coating.

[0292] The film thickness of the protective layer is set, for example, preferably within the range of 1 μm to 20 μm, more preferably within the range of 2 μm to 10 μm.

[0293] (Single-layer photosensitive layer)

[0294] The single-layer photosensitive layer (charge generation / charge transport layer) is, for example, a layer containing a charge generation material and a charge transport material and, if necessary, a binding resin and other known additives. It should be noted that these materials are the same as those described for the charge generation layer and the charge transport layer.

[0295] Furthermore, in the single-layer photosensitive layer, the content of the charge generating material can be 0.1% by mass to 10% by mass, preferably 0.8% by mass to 5% by mass, relative to the total solid content. In addition, in the single-layer photosensitive layer, the content of the charge transport material can be 5% by mass to 50% by mass, relative to the total solid content.

[0296] The method for forming the single-layer photosensitive layer is the same as the method for forming the charge generating layer and the charge transporting layer.

[0297] The film thickness of the single-layer photosensitive layer may be, for example, 5 μm to 50 μm, and preferably 10 μm to 40 μm.

[0298] <Image Forming Apparatus (and Process Cartridge)>

[0299] The image forming apparatus of the present embodiment comprises: an electrophotographic photoreceptor; a charging mechanism for charging the surface of the electrophotographic photoreceptor; an electrostatic latent image forming mechanism for forming an electrostatic latent image on the surface of the charged electrophotographic photoreceptor; a developing mechanism for developing the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image; and a transfer mechanism for transferring the toner image to the surface of a recording medium. As the electrophotographic photoreceptor, the electrophotographic photoreceptor of the present embodiment described above is applied.

[0300] The image forming device of this embodiment can apply the following well-known image forming devices: a device equipped with a fixing mechanism for fixing the toner image transferred to the surface of a recording medium; a device for a direct transfer method for directly transferring the toner image formed on the surface of an electrophotographic photosensitive body to a recording medium; a device for an intermediate transfer method for transferring the toner image formed on the surface of an electrophotographic photosensitive body once to the surface of an intermediate transfer body, and then transferring the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium for a second time; a device equipped with a cleaning mechanism for cleaning the surface of an electrophotographic photosensitive body after the toner image is transferred but before charging; a device equipped with a de-staticizing mechanism for de-staticizing the surface of an electrophotographic photosensitive body by irradiating de-staticizing light to the surface of an electrophotographic photosensitive body after the toner image is transferred but before charging; a device equipped with an electrophotographic photosensitive body heating component for increasing the temperature of the electrophotographic photosensitive body and lowering the relative temperature; and the like.

[0301] In the case of an intermediate transfer type device, the transfer mechanism, for example, is configured as follows: an intermediate transfer body that transfers a toner image on a surface, a primary transfer mechanism that transfers the toner image formed on the surface of an electronic photographic photosensitive body to the surface of the intermediate transfer body for the first time, and a secondary transfer mechanism that transfers the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium for the second time.

[0302] The image forming apparatus of the present embodiment may be any of a dry developing system image forming apparatus and a wet developing system (development system using a liquid developer) image forming apparatus.

[0303] It should be noted that, in the image forming apparatus of the present embodiment, for example, the portion having the electrophotographic photoreceptor may be a box structure (processing box) that can be loaded and unloaded relative to the image forming apparatus. As the processing box, for example, a processing box having the electrophotographic photoreceptor of the present embodiment is suitable for use. It should be noted that, in addition to the electrophotographic photoreceptor, the processing box may also have, for example, at least one selected from the group consisting of a charging mechanism, an electrostatic latent image forming mechanism, a developing mechanism, and a transfer mechanism.

[0304] An example of the image forming apparatus according to the present embodiment is shown below, but the present invention is not limited thereto. It should be noted that the main parts shown in the drawings will be described, and the description of other parts will be omitted.

[0305] Figure 2 This is a schematic structural diagram showing an example of the image forming apparatus according to the present embodiment.

[0306] like Figure 2As shown, the image forming apparatus 100 of the present embodiment includes: a process box 300 including an electrophotographic photoreceptor 7; an exposure device 9 (an example of an electrostatic latent image forming mechanism); a transfer device 40 (a primary transfer device); and an intermediate transfer body 50. It should be noted that in the image forming apparatus 100, the exposure device 9 is arranged at a position where the electrophotographic photoreceptor 7 can be exposed through the opening of the process box 300, and the transfer device 40 is arranged at a position opposite to the electrophotographic photoreceptor 7 across the intermediate transfer body 50, and the intermediate transfer body 50 is arranged so that a part of it contacts the electrophotographic photoreceptor 7. Although not shown in the figure, there is also a secondary transfer device for transferring the toner image transferred to the intermediate transfer body 50 to a recording medium (e.g., paper). It should be noted that the intermediate transfer body 50, the transfer device 40 (a primary transfer device), and the secondary transfer device (not shown) are equivalent to an example of a transfer mechanism.

[0307] Figure 2 The process box 300 in the embodiment integrally supports the electrophotographic photoreceptor 7, the charging device 8 (an example of a charging mechanism), the developing device 11 (an example of a developing mechanism), and the cleaning device 13 (an example of a cleaning mechanism) in a housing. The cleaning device 13 has a cleaning blade (an example of a cleaning member) 131, and the cleaning blade 131 is configured to contact the surface of the electrophotographic photoreceptor 7. It should be noted that the cleaning member may be a conductive or insulating fibrous member other than the cleaning blade 131, and may be used alone or in combination with the cleaning blade 131.

[0308] It should be noted that Figure 2 In the example shown, as the image forming apparatus, a fibrous member 132 (rolled shape) for supplying lubricant 14 to the surface of the electrophotographic photoreceptor 7 and a fibrous member 133 (flat brush shape) for assisting cleaning are provided, but these members are arranged as needed.

[0309] Next, each structure of the image forming apparatus according to this embodiment will be described.

[0310] -Charging device-

[0311] As the charging device 8, for example, a contact type charger using a conductive or semi-conductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube, etc. can be used. In addition, a non-contact roller charger, a scorotron charger using corona discharge, a corona charger, or other chargers known per se can also be used.

[0312] -Exposure device-

[0313] As the exposure device 9, for example, there can be cited an optical system device that uses semiconductor laser, LED light, liquid crystal light valve light and other light to expose the surface of the electrophotographic photoreceptor 7 according to a predetermined image. The wavelength of the light source is set to be within the spectral sensitivity region of the electrophotographic photoreceptor. As the wavelength of the semiconductor laser, near-infrared with an oscillation wavelength around 780nm is the mainstream. However, it is not limited to this wavelength, and a laser with an oscillation wavelength of approximately 600nm or a laser with an oscillation wavelength of more than 400nm and less than 450nm as a blue laser can also be used. In addition, in order to form a color image, a surface-emitting laser source that can output multiple beams is also effective.

[0314] -Developing device-

[0315] As the developing device 11, for example, a general developing device that performs development in contact with or without contact with a developer can be cited. As the developing device 11, there is no particular limitation as long as it has the above-mentioned function, and it can be selected according to the purpose. For example, a well-known developer can be cited, and the well-known developer has a function of attaching a single-component developer or a two-component developer to the electrophotographic photoreceptor 7 using a brush, a roller, etc. Among them, it is preferable to use a developing roller having a developer retained on the surface.

[0316] The developer used in the developing device 11 may be a one-component developer containing only a toner or a two-component developer containing a toner and a carrier. The developer may be magnetic or non-magnetic. These developers may be known developers.

[0317] -Cleaning device-

[0318] The cleaning device 13 is a cleaning blade type device including a cleaning blade 131 .

[0319] In the cleaning scraper 131, from the perspective of making the wear of the surface layer of the photosensitive body uniform, the contact portion with the electrophotographic photosensitive body is preferably composed of a component in which the ratio (EIT / Re) of the indentation elastic modulus (EIT [MPa]) to the rebound elastic modulus (Re [%]) is greater than 0.65 and the rebound elastic modulus (Re [%]) is greater than 25%.

[0320] The cleaning blade 131 preferably has a member satisfying the above-mentioned characteristics at least in the contact portion with the electrophotographic photoreceptor (hereinafter referred to as "contact member"). That is, it may be a two-layer structure having a first layer formed by the contact member and in contact with the surface of the electrophotographic photoreceptor and a second layer as a back layer on the back of the first layer, or a structure of three or more layers. In addition, it may be a structure in which only the corner of the portion in contact with the electrophotographic photoreceptor is formed by the contact member, and the surrounding is formed by other materials.

[0321] Figure 31 is a schematic diagram showing a first example of the cleaning blade 131, which is a diagram showing a state in which the cleaning blade 131A is in contact with the surface of the electrophotographic photoreceptor 7. In addition, Figure 4 131B is a schematic diagram showing a second example of the cleaning blade 131 , which is a diagram showing a state in which the cleaning blade 131B is in contact with the surface of the electrophotographic photoreceptor 7 . Figure 5 1 is a schematic diagram showing a third example of the cleaning blade 131 , which is a diagram showing a state in which the cleaning blade 131C is in contact with the surface of the electrophotographic photoreceptor 7 .

[0322] First use Figure 3 The various parts of the cleaning blade are described below. Figure 3 As shown, the cleaning scraper 131A comprises: a contact portion (contact angle portion) 131AA which contacts the driven electrophotographic photosensitive body 7 to clean the surface of the electrophotographic photosensitive body 7; a front end surface 131AB having a side formed by the contact angle portion 131AA and facing the upstream side of the above-mentioned driving direction (direction of arrow A); a ventral surface 131AC having a side formed by the contact angle portion 131AA and facing the downstream side of the above-mentioned driving direction (direction of arrow A); and a back surface 131AD which shares a side with the front end surface 131AB and is opposite to the ventral surface 131AC.

[0323] In addition, the direction parallel to the contact angle portion 131AA is called the depth direction, the direction from the contact angle portion 131AA to the side where the front end surface 131AB is formed is called the thickness direction, and the direction from the contact angle portion 131AA to the side where the ventral surface 131AC is formed is called the width direction.

[0324] Figure 3 The cleaning blade 131A shown is configured such that the entire cleaning blade 131A including a portion (contact angle portion) 131AA that contacts the electrophotographic photoreceptor 7 is made of a single material, that is, it is configured only by a contact member.

[0325] It should be noted that if Figure 4 As shown in the example, the cleaning scraper 131 can be a two-layer structure having a first layer 131BB and a second layer 131BC as a back layer, wherein the first layer 131BB includes a portion (contact angle portion) 131AA in contact with the electrophotographic photoreceptor 7, formed on the entire surface of the ventral surface 131AC side and composed of a contact component, and the second layer 131BC is formed on the back surface 131AD side of the first layer and is composed of a material different from the contact component.

[0326] In addition, if Figure 5As shown in the example, the cleaning scraper 131 can be a structure having the following parts: a contact part (edge ​​part) 131CA, which includes a portion in contact with the electronic photographic photoreceptor 7, namely, a contact angle portion 131AA, and has a shape of a 1 / 4 cylinder cut and extending in the depth direction, and the right angle portion of the shape forms the contact angle portion 131AA; and a back part 131CC formed by a material different from that of the contact part, which covers the back side 131AD side of the contact part 131CA in the thickness direction and the side opposite to the front end face 131AB in the width direction, namely, constitutes a portion other than the above-mentioned contact part 131CA.

[0327] It should be noted that Figure 5 In the embodiment, a contact member is shown as a member having a cylindrical shape cut into 1 / 4, but the present invention is not limited thereto. The contact member may be, for example, an elliptical cylindrical shape cut into 1 / 4, a square quadrangular prism, a rectangular quadrangular prism, or the like.

[0328] In addition, the cleaning blade is usually used by being bonded to, for example, a rigid plate-like supporting material.

[0329] [Contact parts composition]

[0330] The contact member in the cleaning blade 131 preferably contains polyurethane rubber. Furthermore, the contact member is preferably composed of a member having a ratio (EIT / Re) of indentation elastic modulus (EIT [MPa]) to rebound elastic modulus (Re [%]) of 0.65 or more and a rebound elastic modulus (Re [%]) of 25% or more.

[0331] Polyurethane rubber

[0332] The polyurethane rubber is obtained by polymerizing at least a polyol component and a polyisocyanate component. The polyurethane rubber may be obtained by polymerizing a resin having a functional group reactive with an isocyanate group of a polyisocyanate in addition to the polyol component as required.

[0333] The polyurethane rubber preferably has a hard segment and a soft segment. The "hard segment" and "soft segment" refer to segments in which the material constituting the former is formed of a relatively harder material than the material constituting the latter, and the material constituting the latter is formed of a relatively softer material than the material constituting the former.

[0334] It should be noted that, as the material constituting the hard segment (hard segment material), there can be mentioned low molecular weight polyol components among the polyol components, resins having functional groups that can react with isocyanate groups of polyisocyanates, etc. On the other hand, as the material constituting the soft segment (soft segment material), there can be mentioned high molecular weight polyol components among the polyol components.

[0335] Here, the average particle size of the agglomerates of the hard segments is preferably 1 μm or more and 10 μm or less, and more preferably 1 μm or more and 5 μm or less.

[0336] By setting the average particle size of the hard segment aggregates to be 1 μm or more, the friction resistance of the contacting member surface can be easily reduced, thereby stabilizing the blade behavior and suppressing local wear.

[0337] On the other hand, by setting the average particle size of the hard segment aggregates to 10 μm or less, the generation of notches can be easily suppressed.

[0338] The average particle size of the hard segment agglomerates was measured as follows: an image was captured at a magnification of ×20 using a polarizing microscope (BX51-P manufactured by Olympus), the image was processed to binary, and the particle size of the agglomerates was measured at 5 locations per cleaning blade (the particle size of 5 agglomerates was measured at each location), and the particle size of the agglomerates (equivalent circle diameter) was measured for 20 cleaning blades, and the average particle size was calculated from a total of 500 agglomerate particle sizes.

[0339] The image was binarized using image processing software OLYMPUS Stream essentials (manufactured by Olympus Corporation), and the thresholds of hue / chroma / brightness were adjusted so that the crystal part and the aggregate of the hard segment were black and the amorphous part (equivalent to the soft segment) was white.

[0340] Polyol ingredients

[0341] The polyol component preferably contains a high molecular weight polyol and a low molecular weight polyol.

[0342] The high molecular weight polyol component is preferably a polyol having a number average molecular weight of 500 or more (preferably 500 or more and 5000 or less). As the high molecular weight polyol component, polyester polyols obtained by dehydration condensation of low molecular weight polyols and dibasic acids, polycarbonate polyols obtained by reaction of low molecular weight polyols and alkyl carbonates, polycaprolactone polyols, polyether polyols and other known polyols can be cited. It should be noted that commercial products of high molecular weight polyols, for example, PRAXCELL 205 and PRAXCELL 240 manufactured by Daicel Chemical Company can be cited.

[0343] Here, the number average molecular weight is a value measured by gel permeation chromatography (GPC). The same applies to the following.

[0344] These high molecular weight polyols may be used alone or in combination of two or more.

[0345] The polymerization ratio of the high molecular weight polyol component may be 30 mol% to 50 mol%, preferably 40 mol% to 50 mol%, based on the total polymerization components of the polyurethane rubber.

[0346] The low-molecular-weight polyol component is preferably a polyol having a molecular weight (number average molecular weight) of less than 500. The low-molecular-weight polyol is a material that functions as a chain extender and a cross-linking agent.

[0347] As the low molecular weight polyol component, 1,4-butanediol is preferred. The ratio of 1,4-butanediol relative to the total polyol components (high molecular weight polyol + low molecular weight polyol) is preferably greater than 50 mol% and less than 75 mol% (preferably 52 mol% to 75 mol%, more preferably 55 mol% to 75 mol%, further preferably 55 mol% to 60 mol%).

[0348] The ratio of 1,4-butanediol to the total low molecular weight polyol components is preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 100 mol%. That is, 1,4-butanediol is most preferably used as the total low molecular weight polyol components.

[0349] As the low molecular weight polyol component, in addition to 1,4-butanediol, there can be mentioned diol (bifunctional), triol (trifunctional) or tetraol (tetrafunctional) which are known as chain extenders and crosslinking agents.

[0350] These polyols other than 1,4-butanediol may be used alone or in combination of two or more.

[0351] The polymerization ratio of the low molecular weight polyol component can be greater than 50 mol% and less than 75 mol% relative to the total polymerization components of the polyurethane rubber, preferably from 52 mol% to 75 mol%, more preferably from 55 mol% to 75 mol%, and further preferably from 55 mol% to 60 mol%.

[0352] Polyisocyanate ingredients

[0353] Examples of the polyisocyanate component include 4,4′-diphenylmethane diisocyanate (MDI), 2,6-toluene diisocyanate (TDI), 1,6-hexane diisocyanate (HDI), 1,5-naphthalene diisocyanate (NDI), and 3,3-dimethylbiphenyl-4,4-diisocyanate (TODI).

[0354] As the polyisocyanate component, 4,4′-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), and hexamethylene diisocyanate (HDI) are more preferred.

[0355] These polyisocyanate components may be used alone or in combination of two or more.

[0356] The polymerization ratio of the polyisocyanate component may be 5 mol% to 25 mol%, preferably 10 mol% to 20 mol%, based on the total polymerization components of the polyurethane rubber.

[0357] Resins having functional groups that react with isocyanate groups

[0358] The resin having a functional group that can react with an isocyanate group (hereinafter referred to as "functional group-containing resin") is preferably a flexible resin, and more preferably an aliphatic resin having a linear structure from the perspective of flexibility. Specific examples of the functional group-containing resin include acrylic resins containing two or more hydroxyl groups, polybutadiene resins containing two or more hydroxyl groups, and epoxy resins having two or more epoxy groups.

[0359] Examples of commercially available products of acrylic resins containing two or more hydroxyl groups include ACTFLOW manufactured by Soken Chemical Industries, Ltd. (grades: UMB-2005B, UMB-2005P, UMB-2005, UME-2005, etc.).

[0360] Examples of commercially available products of the polybutadiene resin containing two or more hydroxyl groups include R-45HT manufactured by Idemitsu Kosan Co., Ltd.

[0361] As the epoxy resin having two or more epoxy groups, it is preferred that it is not hard and brittle like the conventional epoxy resin, but is softer and tougher than the conventional epoxy resin. As the epoxy resin, for example, in terms of molecular structure, it is suitable to have a structure (flexible skeleton) that can improve the mobility of the main chain in its main chain structure, and as the flexible skeleton, an alkylene skeleton, a cycloalkane skeleton, a polyoxyalkylene skeleton, etc. can be cited, and a polyoxyalkylene skeleton is particularly suitable.

[0362] In addition, in terms of physical properties, an epoxy resin having a lower viscosity / molecular weight ratio than existing epoxy resins is suitable. Specifically, the weight average molecular weight is within the range of 900±100, and the viscosity at 25°C is preferably within the range of 15000±5000 mPa·s, and more preferably within the range of 15000±3000 mPa·s. Commercially available epoxy resins having such properties include, for example, EPLICON EXA-4850-150 manufactured by DIC.

[0363] ·Production method of polyurethane rubber

[0364] The polyurethane rubber is produced by a common polyurethane production method such as a prepolymer method and a one-shot method. The prepolymer method is preferred because it can produce polyurethane with excellent wear resistance and chipping resistance, but the polyurethane rubber is not limited to the production method.

[0365] In the molding of the cleaning blade, the cleaning blade-forming composition prepared by the above method is formed into a sheet by centrifugal molding, extrusion molding, etc., and then cut to produce the cleaning blade.

[0366] Here, examples of the catalyst used in the production of the polyurethane rubber include amine compounds such as tertiary amines, quaternary ammonium salts, and organic metal compounds such as organic tin compounds.

[0367] Examples of the tertiary amine include trialkylamines such as triethylamine, tetraalkyldiamines such as N,N,N',N'-tetramethyl-1,3-butanediamine, amino alcohols such as dimethylethanolamine, ethoxylated amines, ethoxylated diamines, esteramines such as bis(diethylethanolamine) adipate, triethylenediamine (TEDA), cyclohexylamine derivatives such as N,N-dimethylcyclohexylamine, morpholine derivatives such as N-methylmorpholine and N-(2-hydroxypropyl)-dimethylmorpholine, piperazine derivatives such as N,N'-diethyl-2-methylpiperazine and N,N'-bis(2-hydroxypropyl)-2-methylpiperazine, and the like.

[0368] Examples of the quaternary ammonium salt include 2-hydroxypropyltrimethylammonium octanoate, 1,5-diazabicyclo[4.3.0]nonene-5(DBN)octanoate, 1,8-diazabicyclo[5.4.0]undecene-7(DBU)octanoate, DBU-oleate, DBU-p-toluenesulfonate, DBU-formatate, and 2-hydroxypropyltrimethylammonium formate.

[0369] Examples of the organic tin compound include dialkyltin compounds such as dibutyltin dilaurate and dibutyltin di(2-ethylhexanoate), stannous 2-ethylhexanoate, and stannous oleate.

[0370] Among these catalysts, triethylenediamine (TEDA) as a tertiary amine is used from the aspect of hydrolysis resistance, and quaternary ammonium salts are preferably used from the aspect of processability. Among the quaternary ammonium salts, 1,5-diazabicyclo[4.3.0]nonene-5(DBN)·octanoate, 1,8-diazabicyclo[5.4.0]undecene-7(DBU)-octanoate, and DBU-formate, which have high reactivity, are preferably used.

[0371] The content of the catalyst is preferably in the range of 0.0005 mass % to 0.03 mass % of the entire polyurethane rubber constituting the contact member, and particularly preferably in the range of 0.001 mass % to 0.01 mass %.

[0372] These catalysts are used alone or in combination of two or more.

[0373] [Physical properties of contact parts]

[0374] In the cleaning scraper 131, from the perspective of uniformly wearing the surface layer of the photosensitive body, the contact portion with the electrophotographic photosensitive body is preferably composed of a component having a ratio (EIT [MPa]) of indentation elastic modulus (EIT [MPa]) to rebound elastic modulus (Re [%]) (EIT / Re) of 0.65 or more and a rebound elastic modulus (Re [%]) of 25% or more.

[0375] From the perspective of uniformly wearing the surface layer of the photoreceptor, the EIT / Re ratio (ratio of indentation elastic modulus (EIT [MPa]) to rebound elastic modulus (Re [%])) of the contact member (polyurethane rubber member) is preferably 0.65 or more, more preferably 0.75 or more, and further preferably 0.85 or more. It should be noted that from the perspective of chipping resistance, the upper limit of the EIT / Re ratio of the contact member is preferably 1.1 or less, and more preferably 1.0 or less.

[0376] The rebound elastic modulus (Re[%]) of the contact part (polyurethane rubber part) is preferably 25% or more, more preferably 28% or more, and further preferably 30% or more. It should be noted that from the perspective of suppressing scraper screaming and wear resistance, the upper limit of the rebound elastic modulus (Re[%]) of the contact part is preferably 60% or less, and more preferably 40% or less.

[0377] The indentation elastic modulus (EIT [MPa]) of the contact member (urethane rubber member) is preferably 10 MPa to 30 MPa, and more preferably 15 MPa to 25 MPa.

[0378] According to ISO 14577 (2002), the indentation modulus (EIT) is measured from the slope of the load range of 65% to 95% of the maximum load in the unloading curve obtained in the load-penetration curve of the indenter. The measurement conditions are as follows.

[0379] · Measurement device: Nanoindentation dynamic ultra-micro hardness tester "trade name PICODENTOR HM500 (manufacturer: Fischer Instruments)"

[0380] Indenter: Berkovich-type diamond indenter with a conical shape and a face angle of 120°

[0381] ·Indenter penetration depth: 20μm

[0382] ·Indenter insertion speed: 12.5μm / sec

[0383] · Unloading speed of pressure head: 12.5m / s

[0384] The rebound elastic modulus was determined in accordance with JIS K6255 (1996) using a Lubbock-type rebound elasticity tester in an environment of 23°C.

[0385] [Composition of non-contact parts]

[0386] Then for Figure 4 or Figure 5 The composition of the non-contact member will be described by taking as an example a case where the contact member of the cleaning blade 131 and a region other than the contact member (non-contact member) are made of different materials.

[0387] As long as the non-contact component has the function of supporting the contact component, any known material can be used without particular limitation. Specifically, as the material used in the non-contact component, for example, polyurethane rubber, silicone rubber, fluororubber, chloroprene rubber, butadiene rubber, etc. can be cited. Among these, polyurethane rubber is preferred. As polyurethane rubber, ester polyurethane and ether polyurethane can be cited, and ester polyurethane is particularly preferred.

[0388] [Manufacture of cleaning blade]

[0389] exist Figure 3 In the case of the cleaning blade formed of only the contact member shown, the cleaning blade is manufactured by the above-mentioned contact member molding method.

[0390] In addition, Figure 4 In the case of a cleaning scraper with a multilayer structure such as the two-layer structure shown, the cleaning scraper is made by laminating the first layer as a contact component and the second layer (multilayer in the case of a layer structure of more than three layers) as a non-contact component. As the above-mentioned laminating method, double-sided tape, various adhesives, etc. can be appropriately used. In addition, it is also possible to set a time difference during molding so that each layer of material flows into the mold, and the materials are combined without setting an adhesive layer, thereby bonding multiple layers.

[0391] In addition, Figure 5 In the case of the structure having a contact part (edge ​​part) and a non-contact part (back part) as shown in the figure, a first mold and a second mold are prepared, wherein the first mold has two Figure 5The second mold has a cavity corresponding to the shape formed by overlapping the two contact parts 131CA and the non-contact part 131CC on the ventral surface 131AC side. The contact part forming composition is flowed into the cavity of the first mold and solidified to form a first molded product in the shape of the two contact parts 131CA overlapping each other. Next, after removing the first mold, the second mold is further set in such a manner that the first molded product is arranged inside the cavity of the second mold. Thereafter, the non-contact part forming composition is flowed into the cavity of the second mold in such a manner as to cover the first molded product and solidified to form a second molded product in the shape of the two contact parts 131CA and the non-contact part 131CC overlapping each other on the ventral surface 131AC side. Next, the second molded product is cut in the middle (i.e., the portion that becomes the ventral surface 131AC), and the semi-cylindrical contact part is cut in the middle to become a 1 / 4 cylindrical shape, and further cut into a predetermined size, thereby obtaining Figure 5 Cleaning blade shown.

[0392] It should be noted that in addition to the cleaning blade method, a brush cleaning method and a simultaneous development and cleaning method may also be used.

[0393] -Transfer device-

[0394] Examples of the transfer device 40 include known transfer chargers such as a contact transfer charger using a belt, a roller, a film, a rubber blade, or the like, a scorotron transfer charger using corona discharge, and a corona transfer charger.

[0395] -Intermediate transfer body-

[0396] A belt-shaped transfer body (intermediate transfer belt) made of polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber, etc. imparted with semiconductivity is used as the intermediate transfer body 50. In addition, a drum-shaped transfer body can be used as the intermediate transfer body in addition to a belt-shaped transfer body.

[0397] Figure 6 This is a schematic structural diagram showing another example of the image forming apparatus according to the present embodiment.

[0398] Figure 6The image forming apparatus 120 shown is a multi-color image forming apparatus of a tandem type equipped with four process cartridges 300. In the image forming apparatus 120, the four process cartridges 300 are arranged in parallel on the intermediate transfer body 50, and one electrophotographic photoreceptor is used for each color. It should be noted that the image forming apparatus 120 has the same structure as the image forming apparatus 100 except that it is a tandem type.

[0399] [Example]

[0400] The following examples are described, but the present invention is not limited to the following examples. It should be noted that in the following description, "parts" and "%" are all based on mass unless otherwise specified.

[0401] <Production of fluorine-containing resin particles>

[0402] (Production of fluorine-containing resin particles (1))

[0403] The fluorine-containing resin particles (1) were produced as follows.

[0404] 3 liters of deionized water, 3.0 g of ammonium perfluorooctanoate, and 110 g of solid paraffin (manufactured by Nippon Oil Corporation) as an emulsion stabilizer were added to the autoclave, and the system was replaced with nitrogen three times and TFE (tetrafluoroethylene) twice to remove oxygen. Then, the internal pressure was set to 1.0 MPa using TFE, and the internal temperature was maintained at 70°C while stirring at 250 rpm. Then, 150 cc of ethane at normal pressure as a chain transfer agent and 20 ml of an aqueous solution containing 300 mg of ammonium persulfate as a polymerization initiator were added to the system to initiate the reaction. During the reaction, the temperature in the system was maintained at 70°C, and TFE was continuously supplied in such a manner that the internal pressure of the autoclave was always maintained at 1.0 ± 0.05 MPa. After the initiator was added, the supply and stirring of TFE were stopped when the TFE consumed in the reaction reached 1000 g, and the reaction was terminated. The particles were then separated by centrifugal separation, and 400 parts by mass of methanol were collected and washed with a stirrer at 250 rpm for 10 minutes while irradiating with ultrasonic waves, and the supernatant was filtered out. This operation was repeated three times, and the filtrate was dried at 60 degrees for 17 hours under reduced pressure.

[0405] Through the above steps, fluorine-containing resin particles (1) are produced.

[0406] (Production of fluorine-containing resin particles (2))

[0407] The fluorine-containing resin particles (2) were produced as follows.

[0408] 100 parts by mass of commercially available homopolytetrafluoroethylene fine powder (standard specific gravity: 2.175 measured according to ASTM D 4895 (2004)) and 2.4 parts by mass of ethanol as an additive were collected in a barrier nylon bag, and the entire bag was purged with nitrogen so that the oxygen concentration reached 10%. Thereafter, 150 kGy of cobalt-60 gamma rays were irradiated at room temperature to obtain a low molecular weight polytetrafluoroethylene powder. The obtained powder was pulverized to obtain fluorine-containing resin particles (2).

[0409] (Production of fluorine-containing resin particles (C1))

[0410] The fluorine-containing resin particles (C1) were produced as follows.

[0411] 100 parts by mass of commercially available homopolytetrafluoroethylene fine powder (standard specific gravity 2.175 measured according to ASTM D 4895 (2004)) and 2.4 parts by mass of ethanol as an additive were collected in a barrier nylon bag. The bag was then irradiated with 150 kGy of cobalt-60 gamma rays in air at room temperature to obtain a low molecular weight polytetrafluoroethylene powder. The obtained powder was crushed to obtain fluorine-containing resin particles (C1).

[0412] (Production of fluorine-containing resin particles (C2))

[0413] The fluorine-containing resin particles (C2) were produced as follows.

[0414] 100 parts by mass of commercially available homopolytetrafluoroethylene fine powder (standard specific gravity: 2.175 measured according to ASTM D 4895 (2004)) and 2.4 parts by mass of ethanol as an additive were collected in a barrier nylon bag, and the entire bag was purged with nitrogen so that the oxygen concentration reached 15%. Thereafter, 150 kGy of cobalt-60 gamma rays were irradiated at room temperature to obtain a low molecular weight polytetrafluoroethylene powder. The obtained powder was crushed to obtain fluorine-containing resin particles (C2).

[0415] <Production of fluorinated graft polymer>

[0416] The fluorine-containing graft polymer was produced as follows.

[0417] 5 parts by mass of methyl isobutyl ketone were added to a 500 mL reaction container equipped with a stirring device, a reflux cooling tube, a thermometer and a nitrogen blowing port and stirred, and the temperature of the solution in the reaction container was maintained at 80°C under a nitrogen atmosphere. A mixed solution of 9 parts by mass of perfluorohexyl ethyl acrylate, 21 parts by mass of macromonomer AA-6 (manufactured by Toagosei Co., Ltd.), 0.2 parts by mass of Perhexyl O (manufactured by NOF Corporation) as a polymerization initiator, and 45 parts by mass of methyl isobutyl ketone was added dropwise to the reaction container using a syringe dropping pump over a period of 2 hours. After the addition was completed, stirring was continued for further 2 hours, and then the solution temperature was raised to 90°C and stirred for further 2 hours.

[0418] To the methyl isobutyl ketone resin solution obtained after the reaction, 400 ml of methanol was added dropwise to precipitate a fluorinated graft polymer. The precipitated solid component was filtered out and dried to obtain a fluorinated graft polymer.

[0419] <Manufacturing of cleaning blade>

[0420] <Cleaning Blades (1) to (7), Cleaning Blades (C1) to (C4)>

[0421] According to Table 1, the types and molar ratios of the high molecular weight polyol component, the low molecular weight polyol component and the isocyanate component, and the curing and aging conditions were changed according to the polyol compounding ratio to prepare a cleaning blade.

[0422] First, adipic acid (HOOC-C 4 H 8 -COOH) and 1,4-butanediol were polymerized at a ratio of 1:1 (molar ratio), and the terminal was treated to be -OH to obtain a polyester polyol obtained by polymerizing a straight-chain diol (butanediol) having 4 carbon atoms. The number average molecular weight of the obtained polyester polyol was 2000.

[0423] Next, polyester polyol as a polymer polyol component, 1,4-butanediol (1,4-BD, chain extender) as a low molecular weight polyol, 4,4'-diphenylmethane diisocyanate (MDI, polyisocyanate, manufactured by Nippon Polyurethane Industries, Ltd., Millionate MT) as an isocyanate, and trimethylolpropane (TMP, manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a crosslinking agent were reacted at 80°C for 2 hours in a nitrogen atmosphere in the blending amounts (molar ratio) shown in Table 1 to prepare a cleaning blade forming composition A1.

[0424] Next, the cleaning blade forming composition A1 was poured into a centrifugal molding machine whose mold was adjusted to 140°C, and cured under the curing and aging conditions shown in Table 1, followed by aging heating. The cooled solidified product was cut to obtain a cleaning blade having a width of 8 mm and a thickness of 2 mm.

[0425] In the cleaning blade (6), polytetramethylene ether glycol (PTMG) is used as the high molecular weight polyol component.

[0426] In addition, the curing and aging conditions A to E shown in Table 1 are as follows.

[0427] Curing and aging conditions A: After curing reaction at 100℃ for 1 hour, aging heating at 110℃ for 24 hours

[0428] Curing and aging conditions B: After curing reaction at 110℃ for 1 hour, aging heating at 110℃ for 24 hours

[0429] Curing and aging conditions C: After 2 hours of curing reaction at 110°C, 48 hours of aging heating at 110°C

[0430] Curing and aging conditions D: Curing reaction at 100°C for 40 minutes, followed by aging heating at 110°C for 24 hours

[0431] Curing and aging conditions E: After curing reaction at 100°C for 40 minutes, aging heating at 100°C for 24 hours

[0432] In addition, "mol %" described in Table 1 is the value of the mol % of each component relative to the total polyol components (high molecular weight polyol + low molecular weight polyol).

[0433] <Example 1>

[0434] -Production of photoreceptor-

[0435] Using the obtained fluorine-containing resin particles, a photoreceptor was produced as follows.

[0436] Zinc oxide (average particle size 70 nm: manufactured by TAYCA; specific surface area 15 m 2 / g) and 500 parts of tetrahydrofuran were stirred and mixed, and 1.4 parts of a silane coupling agent (KBE503: manufactured by Shin-Etsu Chemical Co., Ltd.) were added and stirred for 2 hours. The tetrahydrofuran was then distilled off by reduced pressure distillation, and the mixture was calcined at 120°C for 3 hours to obtain zinc oxide surface treated with a silane coupling agent.

[0437] 110 parts of the surface-treated zinc oxide and 500 parts of tetrahydrofuran were stirred and mixed, and a solution prepared by dissolving 0.6 parts of alizarin in 50 parts of tetrahydrofuran was added, followed by stirring at 50° C. for 5 hours. The zinc oxide to which alizarin was imparted was then filtered out by vacuum filtration, and further dried under reduced pressure at 60° C. to obtain zinc oxide with alizarin.

[0438] 60 parts of the zinc oxide with alizarin, 13.5 parts of a curing agent (blocked isocyanate Sumidur 3175, manufactured by Sumitomo-Bayer Urethane Co., Ltd.), 15 parts of a butyral resin (S-LECBM-1, manufactured by Sekisui Chemical Co., Ltd.), and 85 parts of methyl ethyl ketone were mixed to obtain a mixed solution. 38 parts of the mixed solution was mixed with 25 parts of methyl ethyl ketone and the mixture was stirred for 2 hours. The glass beads were dispersed using a sand mill for 2 hours to obtain a dispersion.

[0439] 0.005 parts of dioctyltin dilaurate and 30 parts of silicone resin particles (TOSPEARL 145, Momentive Performance Materials Japan) were added to the obtained dispersion as a catalyst to obtain a primer coating solution. The coating solution was applied to a cylindrical aluminum substrate by dip coating and dried and cured at 170° C. for 30 minutes to obtain a primer layer with a thickness of 24 μm.

[0440] Next, 1 part of hydroxygallium phthalocyanine (which has strong diffraction peaks at Bragg angles (2θ±0.2°) of 7.5°, 9.9°, 12.5°, 16.3°, 18.6°, 25.1°, and 28.3° in its X-ray diffraction spectrum) was mixed with 1 part of polyvinyl butyral (S-LECBM-5, manufactured by Sekisui Chemical Co., Ltd.) and 80 parts of n-butyl acetate, and the mixture was dispersed together with glass beads using a paint shaker for 1 hour to prepare a coating solution for a charge generation layer. The obtained coating solution was dip-coated on the conductive support having the undercoat layer formed thereon, and dried by heating at 130°C for 10 minutes to form a charge generation layer having a film thickness of 0.15 μm.

[0441] 45 parts of a benzidine compound represented by the following formula (CTM1) as a charge transport material and 55 parts of a polymer compound (viscosity-average molecular weight: 40,000) having a repeating unit represented by the following formula (PCZ1) as a binder resin were dissolved in 150 parts of toluene and 350 parts of tetrahydrofuran, 8 parts of fluorine-containing resin particles (1), 0.4 parts of a fluorine-containing grafted polymer and 0.06 parts of a silicone defoamer (trade name: KP-340 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a defoamer (D1) (50 ppm relative to the silicone component of the outermost surface layer) were added, and the mixture was treated 5 times using a high-pressure homogenizer to prepare a coating liquid for a charge transport layer.

[0442] The obtained coating liquid was applied onto the charge generating layer by dip coating, and heated at 130° C. for 45 minutes to form a charge transporting layer having a film thickness of 31 μm.

[0443] [Chemistry 5]

[0444]

[0445] [Chemistry 6]

[0446]

[0447] Each photoreceptor is manufactured through the above steps.

[0448] (Processing Box Production)

[0449] The prepared photoreceptor was installed in a process cartridge equipped with a cleaning blade (1) of an image forming apparatus (DocuCentre-V C7775, manufactured by Fuji Xerox Corporation) to obtain a process cartridge.

[0450] <Examples 2 to 30, Comparative Examples 1 to 10>

[0451] A photoreceptor and a process cartridge were prepared in the same manner as in Example 1 except that the type and amount of fluorine-containing resin particles, the amount of fluorine-containing graft polymer, the type and amount of defoaming agent, and the type of cleaning blade were changed as shown in Tables 2 to 4.

[0452] <Evaluation>

[0453] (Bubble Generation Evaluation)

[0454] In each example, the presence or absence of bubbles during coating of the charge transport layer was visually confirmed and judged based on the following criteria.

[0455] -Bubble Evaluation Criteria-

[0456] A(○): No bubbles generated

[0457] B(△): Slightly generate bubbles

[0458] C(×): Generates a large number of bubbles

[0459] (Evaluation of Dispersibility of Fluorine-Containing Resin Particles)

[0460] For the photoreceptor obtained in each example, a single-sided blade for trimming (Camiso, manufactured by Nissin EM Co., Ltd.) was used to cut a laminated slice from the primer layer to the outermost surface layer, and the slice was embedded in a photocurable acrylic resin (product name D-800: manufactured by JEOL Datum). Then, a diamond knife was used to cut the laminated slice in a manner that the cross section of the laminated slice appeared using a slicing method (slicing device: manufactured by LEICA). The cross section of the slice was observed using a laser microscope OLS-1100 manufactured by Olympus Optical Industries, Ltd. at a step size of 0.01 μm, and judged according to the following criteria.

[0461] -Evaluation Criteria-

[0462] A (○): No agglutination was observed

[0463] B (△): Weak agglutination was partially observed

[0464] C(×): Significant agglutination was observed

[0465] (Actual machine evaluation)

[0466] -Evaluation Image Forming Device-

[0467] The obtained electrophotographic photoreceptor was mounted in DocuCentre-VC7775 manufactured by Fuji Xerox Co., Ltd. A surface potential meter (Trek 334 manufactured by Trek Co., Ltd.) was used, and a surface potential probe was set at a position 1 mm from the surface of the photoreceptor in the region to be measured.

[0468] This apparatus was used as an image forming apparatus for evaluating the chargeability maintenance and residual potential described below.

[0469] (Evaluation of chargeability maintenance)

[0470] The charging properties of the obtained photoreceptor were evaluated as follows.

[0471] The surface potential after charging was set to -700 V using an evaluation image forming apparatus, and then 70,000 sheets of halftone images with an image density of 30% were output on A4 paper in a high temperature and high humidity environment (temperature 28°C, humidity 85% RH). The surface potential was then measured using a surface potentiometer and evaluated according to the following evaluation criteria.

[0472] A(○): Surface potential is -700 V or more and less than -680 V

[0473] B(△): Surface potential is above -680V and less than -660V

[0474] C(×): Surface potential is -660V or higher and less than -640V

[0475] (Evaluation of residual potential)

[0476] The residual potential of the obtained photoreceptor was evaluated as follows.

[0477] The surface potential after charging was set to -700 V using an evaluation image forming apparatus, and 70,000 sheets of a halftone image with an image density of 30% were output on A4 paper in a high temperature and high humidity environment (temperature 28°C, humidity 85% RH).

[0478] Thereafter, the initial residual potential of the photoreceptor after 100 sheets of printing and the residual potential over time of the photoreceptor after 70,000 sheets of printing and the difference (absolute value) were determined and evaluated according to the following criteria.

[0479] A(○): The difference in residual potential is less than 10V

[0480] B(△): The difference in residual potential is greater than 10V and less than 20V

[0481] C(×): The difference in residual potential is more than 20V

[0482] The records in Tables 2 to 4 are described below.

[0483] The defoaming agent type "D2" is a fluorine-based defoaming agent (product name: Surflon S-651, manufactured by AGC Seimi Chemical Co., Ltd.).

[0484] “-” indicates that the corresponding ingredient is not contained.

[0485]

[0486]

[0487]

[0488]

[0489] From the above results, it can be seen that the residual potential of the photoreceptor of this example is reduced and the generation of bubbles on the surface of the outermost surface layer is suppressed.

Claims

1. A process cartridge for loading and unloading in an image forming apparatus, comprising an electrophotographic photoreceptor and a cleaning mechanism, wherein: The electrophotographic photoreceptor comprises a conductive substrate and a photosensitive layer provided on the conductive substrate. The outermost surface layer of the electrophotographic photoreceptor contains fluorine-containing resin particles, a fluorine-containing graft polymer and a defoaming agent. The number of carboxyl groups contained in the fluorine-containing resin particles is relative to 10 6 The number of carbon atoms is 7 or more but less than 30. The dielectric constant of the outermost surface layer is not less than 3.75 and not more than 3.

90. The pure water contact angle of the outermost surface layer is 90° or more. The content of the fluorinated graft polymer is 4.5% by mass or more and 9.0% by mass or less relative to the content of the fluorinated resin particles. The content of the defoaming agent in the outermost surface layer is 10 ppm or more and 10000 ppm or less, The cleaning mechanism includes a cleaning blade that contacts the surface of the electrophotographic photoreceptor to clean the surface. The contact portion of the cleaning blade that contacts the electrophotographic photoreceptor is composed of a component having a ratio (EIT [MPa]) of indentation elastic modulus (EIT [MPa]) to rebound elastic modulus (Re [%]) (EIT / Re) of 0.65 to 1.39 and a rebound elastic modulus (Re [%]) of 28% or more.

2. A process cartridge according to claim 1, wherein: The dielectric constant of the outermost surface layer is not less than 3.80 and not more than 3.

90. The pure water contact angle of the outermost surface layer is 95° or more.

3. A process cartridge according to claim 1, wherein: The defoaming agent is at least one selected from silicone defoaming agents and fluorine defoaming agents.

4. A process cartridge according to claim 3, wherein: The defoaming agent is dimethyl polysiloxane.

5. The process cartridge according to any one of claims 1 to 3, wherein: The content of the defoaming agent is 0.01 mass % or more and 15 mass % or less relative to the content of the fluorine-containing resin particles.

6. A process cartridge according to claim 1, wherein The content of the defoaming agent in the outermost surface layer is 100 ppm to 5000 ppm.

7. An image forming apparatus comprising: Electrophotographic photoreceptor, A charging mechanism is used to charge the surface of the electrophotographic photoreceptor. The electrostatic latent image forming mechanism forms an electrostatic latent image on the charged surface of the electrophotographic photoreceptor. a developing mechanism for developing the electrostatic latent image formed on the surface of the electrophotographic photoreceptor using a developer containing a toner to form a toner image, and The transfer mechanism transfers the toner image to the surface of the recording medium. Cleaning agencies, in, The electrophotographic photoreceptor comprises a conductive substrate and a photosensitive layer provided on the conductive substrate. The outermost surface layer of the electrophotographic photoreceptor contains fluorine-containing resin particles, a fluorine-containing graft polymer and a defoaming agent. The number of carboxyl groups contained in the fluorine-containing resin particles is relative to 10 6 The number of carbon atoms is 7 or more but less than 30. The dielectric constant of the outermost surface layer is not less than 3.75 and not more than 3.

90. The pure water contact angle of the outermost surface layer is 90° or more. The content of the fluorinated graft polymer is 4.5% by mass or more and 9.0% by mass or less relative to the content of the fluorinated resin particles. The content of the defoaming agent in the outermost surface layer is 10 ppm or more and 10000 ppm or less, The cleaning mechanism includes a cleaning blade that contacts the surface of the electrophotographic photoreceptor to clean the surface. The contact portion of the cleaning blade that contacts the electrophotographic photoreceptor is composed of a component having a ratio (EIT [MPa]) of indentation elastic modulus (EIT [MPa]) to rebound elastic modulus (Re [%]) (EIT / Re) of 0.65 to 1.39 and a rebound elastic modulus (Re [%]) of 28% or more.

8. The image forming apparatus according to claim 7, wherein: The dielectric constant of the outermost surface layer is not less than 3.80 and not more than 3.

90. The pure water contact angle of the outermost surface layer is 95° or more.

9. The image forming apparatus according to claim 7 or 8, wherein: The defoaming agent is at least one selected from silicone defoaming agents and fluorine defoaming agents.

10. The image forming apparatus according to claim 9, wherein: The defoaming agent is dimethyl polysiloxane.

11. The image forming apparatus according to claim 7 or 8, wherein: The content of the defoaming agent is 0.01 mass % or more and 15 mass % or less relative to the content of the fluorine-containing resin particles.

12. The image forming apparatus according to claim 7 or 8, wherein: The content of the defoaming agent in the outermost surface layer is 100 ppm to 5000 ppm.

Images