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, an undercoat layer disposed on the conductive substrate and a photosensitive layer disposed on the undercoat layer. The thickness of the undercoat layer is 1 μm to 10 μm. The undercoat layer contains: at least one violacetone compound selected from the group consisting of compounds represented by the following general formula (1) and compounds represented by the following general formula (2); at least one metal oxide particle selected from the group consisting of aluminum oxide particles, iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles and silicon dioxide particles; and a bonding resin.

Description

Technical Field

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

[0002] Japanese Patent Application Laid-Open No. 2011-095665 discloses an electrophotographic photoreceptor in which an intermediate layer and a photosensitive layer are provided in this order on a conductive support, wherein the intermediate layer contains a polyolefin resin and a benzimidazole-based compound.

[0003] Japanese Patent Application Laid-Open No. 2009-288621 discloses an electrophotographic photoreceptor having an undercoat layer and a photosensitive layer provided in this order on a conductive support, wherein the undercoat layer contains an olefin resin and a benzimidazole compound, wherein the olefin resin contains a compound having at least one of a carboxylic acid group and a carboxylic anhydride group as a constituent component.

[0004] Japanese Patent Application Laid-Open No. 2008-310307 discloses an electrophotographic photoreceptor including metal oxide particles in an undercoat layer. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an electronic photographic photosensitive body. Compared with the case where the undercoat layer contains a violaceous ketone compound but does not contain aluminum oxide particles, iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles and silicon dioxide particles but contains zinc oxide particles, titanium oxide particles or tin oxide particles, or compared with the case where the undercoat layer contains a violaceous ketone compound and aluminum oxide particles and the thickness of the undercoat layer is greater than 10 μm, the electronic photographic photosensitive body of the present invention has excellent charging maintenance, can suppress the occurrence of leakage current caused by the penetration of foreign matter, and suppress the increase of residual potential generated when repeatedly forming images.

[0006] Specific means for solving the above technical problems include the following disclosed solutions.

[0007] According to the first embodiment of the present invention, there is provided an electronic photographic photosensitive body comprising: a conductive substrate, an undercoat layer arranged on the conductive substrate, and a photosensitive layer arranged on the undercoat layer, wherein the thickness of the undercoat layer is not less than 1 μm and not more than 10 μm, and the undercoat layer contains: at least one violacetone compound selected from the group consisting of compounds represented by the following general formula (1) and compounds represented by the following general formula (2); at least one metal oxide particle selected from the group consisting of aluminum oxide particles, iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles and silicon dioxide particles; and a binding resin.

[0008] [Chemistry 1]

[0009]

[0010] In the general formula (1), R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 R each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom. 11 With R 12 , R 12 With R 13 and R 13 With R 14 Each of them can independently link to each other to form a ring. 15 With R 16 , R 16 With R 17 and R 17 With R 18 Each of them can be independently linked to each other to form a ring.

[0011] In the general formula (2), R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 and R 28 R each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom. 21 With R 22 , R 22 With R 23 and R 23 With R 24 Each of them can independently link to each other to form a ring. 25 With R 26 , R 26 With R 27 and R 27 With R 28 Each of them can be independently linked to each other to form a ring.

[0012] According to a second aspect of the present invention, the average primary particle size of the at least one metal oxide particle is 10 nm or more and 1000 nm or less.

[0013] According to a third aspect of the present invention, the total content of the at least one metal oxide particle contained in the undercoat layer is 20 mass % or more and 70 mass % or less relative to the total content of the perinone compound contained in the undercoat layer.

[0014] According to a fourth aspect of the present invention, the total volume of the at least one metal oxide particle accounts for 10 volume % to 35 volume % of the undercoat layer.

[0015] According to a fifth aspect of the present invention, the total content of the at least one perirone compound is 50% by mass or more and 70% by mass or less based on the total solid content of the primer layer.

[0016] According to a sixth aspect of the present invention, the adhesive resin includes polyurethane.

[0017] According to a seventh aspect of the present invention, there is provided a process cartridge detachable from an image forming apparatus, the process cartridge comprising the electrophotographic photoreceptor described above.

[0018] According to the 8th scheme of the present invention, there is provided an image forming device comprising: the above-mentioned electrophotographic photosensitive body; a charging unit for charging the surface of the above-mentioned electrophotographic photosensitive body; an electrostatic latent image forming unit for forming an electrostatic latent image on the surface of the above-mentioned electrophotographic photosensitive body after charging; a developing unit for developing the electrostatic latent image formed on the surface of the above-mentioned electrophotographic photosensitive body with a developer containing a toner to form a toner image; and a transfer unit for transferring the above-mentioned toner image to the surface of a recording medium.

[0019] (Effect)

[0020] According to the above-mentioned schemes 1, 2, 3, 4 or 6, an electronic photographic photosensitive body is provided. Compared with the case where the undercoat layer contains a violaceous ketone compound but does not contain aluminum oxide particles, iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles and silicon dioxide particles but contains zinc oxide particles, titanium oxide particles or tin oxide particles, or compared with the case where the undercoat layer contains a violaceous ketone compound and aluminum oxide particles and the thickness of the undercoat layer is greater than 10μm, the electronic photographic photosensitive body provided by the above scheme has excellent charging maintenance, can suppress the occurrence of leakage current caused by the penetration of foreign matter, and suppress the increase of residual potential generated when repeatedly forming images.

[0021] According to the fifth scheme, an electronic photographic photosensitive body is provided. Compared with the case where the total content of the purple ring ketone compound is greater than 70% by weight relative to the total solid content of the undercoat layer, the electronic photographic photosensitive body provided by the scheme has excellent charging maintenance, can suppress the occurrence of leakage current caused by the penetration of foreign matter, and suppress the increase of residual potential generated when repeatedly forming images.

[0022] According to the seventh scheme, a processing box is provided, which has an electronic photographic photosensitive body. Compared with the case where the undercoat layer contains a violaceous ketone compound but does not contain aluminum oxide particles, iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles and silicon dioxide particles but contains zinc oxide particles, titanium oxide particles or tin oxide particles, or compared with the case where the undercoat layer contains a violaceous ketone compound and aluminum oxide particles and the thickness of the undercoat layer is greater than 10 μm, the electronic photographic photosensitive body in the processing box has excellent charging maintenance, can suppress the occurrence of leakage current caused by the penetration of foreign matter, and suppress the increase of residual potential generated when repeatedly forming images.

[0023] According to the above-mentioned eighth scheme, an image forming device is provided, which has an electronic photographic photosensitive body. Compared with the case where the undercoat layer contains a violaceous ketone compound but does not contain aluminum oxide particles, iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles and silicon dioxide particles but contains zinc oxide particles, titanium oxide particles or tin oxide particles, or compared with the case where the undercoat layer contains a violaceous ketone compound and aluminum oxide particles and the thickness of the undercoat layer is greater than 10μm, the electronic photographic photosensitive body in the image forming device has excellent charging maintenance, can suppress the occurrence of leakage current caused by the penetration of foreign matter, and suppress the increase of residual potential generated when repeatedly forming images. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic partial cross-sectional view showing an example of the layer structure of the electrophotographic photoreceptor according to the present embodiment.

[0025] Figure 2 This is a schematic structural diagram showing an example of the image forming apparatus according to the present embodiment.

[0026] Figure 3 This is a schematic structural diagram showing another example of the image forming apparatus according to the present embodiment. DETAILED DESCRIPTION

[0027] The following describes embodiments of the present invention. These descriptions and examples are provided to illustrate the embodiments and are not intended to limit the scope of the embodiments.

[0028] In the present invention, the numerical range expressed using "to" means a range including the numerical values ​​described before and after "to" as the minimum value and the maximum value, respectively.

[0029] In the numerical range recorded in stages in the present invention, the upper limit or lower limit recorded in a numerical range can be replaced by the upper limit or lower limit of the numerical range recorded in other stages. In addition, in the numerical range recorded in the present invention, the upper limit or lower limit of its numerical range can also be replaced by the value shown in the embodiment.

[0030] The term "step" in the present invention includes not only an independent step but also a step that cannot be clearly distinguished from other steps as long as the intended purpose of the step can be achieved.

[0031] Each component in the present invention may contain two or more corresponding substances. In the present invention, when referring to the amount of each component in the 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.

[0032] The main component in the present invention refers to a main component. For example, the main component refers to a component that accounts for 30% by mass or more of the total mass of a mixture of two or more components.

[0033] In the present invention, the electrophotographic photoreceptor is also simply referred to as a photoreceptor.

[0034] <Electrophotographic Photoreceptor>

[0035] The photoreceptor of the present embodiment includes a conductive substrate, an undercoat layer disposed on the conductive substrate, and a photosensitive layer disposed on the undercoat layer.

[0036] Figure 1 An example of the layer structure of the photoreceptor according to the present embodiment is schematically shown. Figure 1 The 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. The photoreceptor 7A may have a layer structure in which a protective layer is further provided on the charge transporting layer 3.

[0037] In the photoreceptor of this embodiment, Figure 1 The photosensitive member 7A shown is a functional separation type in which the charge generating layer 2 and the charge transporting layer 3 are separated, but may be a single-layer type photosensitive layer in which the charge generating layer 2 and the charge transporting layer 3 are integrated.

[0038] In the photosensitive body of the present embodiment, the undercoat layer contains at least one violacetone compound selected from the group consisting of the compound represented by the general formula (1) and the compound represented by the general formula (2), at least one metal oxide particle selected from the group consisting of aluminum oxide particles, iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles and silicon dioxide particles, and a bonding resin, and the thickness of the undercoat layer is not less than 1 μm and not more than 10 μm.

[0039] In the present invention, the compound represented by the general formula (1) is also referred to as a perione compound (1), and the compound represented by the general formula (2) is also referred to as a perione compound (2).

[0040] The photoreceptor of this embodiment has excellent charge retention, can suppress the occurrence of leakage current due to foreign matter penetration, and can suppress the increase in residual potential generated when repeatedly forming images. The reason for this is presumably due to the following mechanism.

[0041] By including at least one of the violacetone compound (1) and the violacetone compound (2) in the undercoat layer, the charge retention of the photoreceptor is improved, but the undercoat layer is softened and leakage current caused by foreign matter penetration is likely to occur; however, by including at least one of aluminum oxide particles, iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles and silicon dioxide particles, which are inorganic particles and insulating materials, the penetration of foreign matter can be physically suppressed and the leakage current can be electrically suppressed. By including the above-mentioned metal oxide particles as insulating materials in the undercoat layer, the residual potential may increase when images are repeatedly formed, but by making the thickness of the undercoat layer relatively thin, not less than 1 μm and not more than 10 μm, the increase in residual potential generated when images are repeatedly formed can be suppressed.

[0042] In this embodiment, the metal oxide particles contained in the undercoat layer together with at least one of the perovinone compound (1) and the perovinone compound (2) are at least one of aluminum oxide particles, iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles, and silicon dioxide particles. Metal oxide particles other than the above (e.g., zinc oxide particles, titanium oxide particles, tin oxide particles) have relatively weak insulation properties and may not be able to fully suppress the occurrence of leakage current.

[0043] The thickness of the primer layer in this embodiment is 10 μm or less from the perspective of suppressing the increase of residual potential generated when repeatedly forming images. If the thickness of the primer layer is greater than 10 μm, the residual potential is likely to increase when repeatedly forming images. From the perspective of suppressing the occurrence of leakage current and the ease of manufacturing the primer layer, the thickness of the primer layer in this embodiment is 1 μm or more.

[0044] Each layer of the photoreceptor according to this embodiment will be described in detail below.

[0045] [Base coating]

[0046] The primer layer contains at least one selected from the group consisting of the purple ring ketone compound (1) and the purple ring ketone compound (2), at least one metal oxide particle selected from the group consisting of aluminum oxide particles, iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles and silicon dioxide particles, and a bonding resin. The primer layer may also contain particles other than the above-mentioned metal oxide particles and other additives.

[0047] -Purple ketone compound (1), purple ketone compound (2)-

[0048] The primer layer contains at least one of a peroxide compound (1) and a peroxide compound (2). The peroxide compound (1) is a compound represented by the following general formula (1). The peroxide compound (2) is a compound represented by the following general formula (2).

[0049] [Chemistry 2]

[0050]

[0051] In the general formula (1), R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 R each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom. 11 With R 12 , R 12 With R 13 and R 13 With R 14 Each of them can independently link to each other to form a ring. 15 With R 16 , R 16 With R 17 and R 17 With R 18 Each of them can be independently linked to each other to form a ring.

[0052] In the general formula (2), R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 and R 28 R each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom. 21 With R 22 , R 22 With R 23 and R 23 With R 24 Each of them can independently link to each other to form a ring. 25 With R 26 , R 26 With R 27 and R 27 With R 28 Each of them can be independently linked to each other to form a ring.

[0053] In the general formula (1), R 11 ~R 18 The alkyl group represented by may be a substituted or unsubstituted alkyl group.

[0054] In the general formula (1), R 11 ~R 18 The unsubstituted alkyl group represented by the above-mentioned group includes a straight-chain alkyl group having 1 to 20 carbon atoms (preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms), a branched-chain alkyl group having 3 to 20 carbon atoms (preferably 3 to 10 carbon atoms), and a cyclic alkyl group having 3 to 20 carbon atoms (preferably 3 to 10 carbon atoms).

[0055] Examples of the straight-chain alkyl group having 1 to 20 carbon atoms include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, tridecyl, n-tetradecyl, n-pentadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, and n-eicosyl.

[0056] Examples of the branched alkyl group having 3 to 20 carbon atoms include isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, isohexyl, sec-hexyl, tert-hexyl, isoheptyl, sec-heptyl, tert-heptyl, isooctyl, sec-octyl, tert-octyl, isononyl, sec-nonyl, tert-nonyl, isodecyl, sec-decyl, tert-decyl, isododecyl, sec-dodecyl, tert-dodecyl, tert-tetradecyl, and tert-pentadecyl.

[0057] Examples of the cyclic alkyl group having 3 to 20 carbon atoms include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, and polycyclic (e.g., bicyclic, tricyclic, spirocyclic) alkyl groups in which these monocyclic alkyl groups are linked.

[0058] Among the above, the unsubstituted alkyl group is preferably a linear alkyl group such as a methyl group and an ethyl group.

[0059] Examples of the substituent in the alkyl group include an alkoxy group, a hydroxyl group, a carboxyl group, a nitro group, and a halogen atom (such as a fluorine atom, a bromine atom, and an iodine atom).

[0060] Examples of the alkoxy group in which the hydrogen atom in the alkyl group is substituted include the following: 11 ~R 18 The same groups as the unsubstituted alkoxy groups represented.

[0061] In the general formula (1), R 11 ~R 18The alkoxy group represented by may be a substituted or unsubstituted alkoxy group.

[0062] In the general formula (1), R 11 ~R 18 Examples of the unsubstituted alkoxy group represented include linear, branched or cyclic alkoxy groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms.

[0063] Specific examples of the linear alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an n-pentyloxy group, an n-hexyloxy group, an n-heptyloxy group, an n-octyloxy group, an n-nonyloxy group, and an n-decyloxy group.

[0064] Specific examples of the branched alkoxy group include isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentyloxy, neopentyloxy, tert-pentyloxy, isohexyloxy, sec-hexyloxy, tert-hexyloxy, isoheptyloxy, sec-heptyloxy, tert-heptyloxy, isooctyloxy, sec-octyloxy, tert-octyloxy, isononyloxy, sec-nonyloxy, tert-nonyloxy, isodecyloxy, sec-decyloxy, and tert-decyloxy.

[0065] Specific examples of the cyclic alkoxy group include a cyclopropyloxy group, a cyclobutyloxy group, a cyclopentyloxy group, a cyclohexyloxy group, a cycloheptyloxy group, a cyclooctyloxy group, a cyclononyloxy group, and a cyclodecyloxy group.

[0066] Among these, as the unsubstituted alkoxy group, a linear alkoxy group is preferred.

[0067] Examples of the substituent in the alkoxy group include an aryl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a hydroxyl group, a carboxyl group, a nitro group, and a halogen atom (such as a fluorine atom, a bromine atom, and an iodine atom).

[0068] Examples of the aryl group in which the hydrogen atom in the alkoxy group is substituted include the following: 11 ~R 18 The same groups as those represented by the unsubstituted aryl groups.

[0069] Examples of the alkoxycarbonyl group in which the hydrogen atom in the alkoxy group is substituted include the following: 11 ~R 18 The same groups as the unsubstituted alkoxycarbonyl groups represented.

[0070] Examples of the aryloxycarbonyl group in which the hydrogen atom in the alkoxy group is substituted include the following: 11 ~R 18 The same groups as the unsubstituted aryloxycarbonyl groups represented.

[0071] In the general formula (1), R 11 ~R 18The aralkyl group represented by may be a substituted or unsubstituted aralkyl group.

[0072] In the general formula (1), R 11 ~R 18 The unsubstituted aralkyl group represented by is preferably an aralkyl group having 7 to 30 carbon atoms, more preferably an aralkyl group having 7 to 16 carbon atoms, and still more preferably an aralkyl group having 7 to 12 carbon atoms.

[0073] Examples of the unsubstituted aralkyl group having 7 to 30 carbon atoms include benzyl, phenylethyl, phenylpropyl, 4-phenylbutyl, phenylpentyl, phenylhexyl, phenylheptyl, phenyloctyl, phenylnonyl, naphthylmethyl, naphthylethyl, anthracenylmethyl, and phenyl-cyclopentylmethyl.

[0074] Examples of the substituent in the aralkyl group include an alkoxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, and a halogen atom (a fluorine atom, a bromine atom, an iodine atom, etc.).

[0075] Examples of the alkoxy group that replaces the hydrogen atom in the aralkyl group include: 11 ~R 18 The same groups as the unsubstituted alkoxy groups represented.

[0076] Examples of the alkoxycarbonyl group in which the hydrogen atom in the aralkyl group is substituted include the following: 11 ~R 18 The same groups as the unsubstituted alkoxycarbonyl groups represented.

[0077] Examples of the aryloxycarbonyl group in which the hydrogen atom in the aralkyl group is substituted include the following: 11 ~R 18 The same groups as the unsubstituted aryloxycarbonyl groups represented.

[0078] In the general formula (1), R 11 ~R 18 The aryl group represented by may be a substituted or unsubstituted aryl group.

[0079] In the general formula (1), R 11 ~R 18 The unsubstituted aryl group represented by is preferably an aryl group having 6 to 30 carbon atoms, more preferably an aryl group having 6 to 14 carbon atoms, and still more preferably an aryl group having 6 to 10 carbon atoms.

[0080] Examples of the aryl group having 6 to 30 carbon atoms include phenyl, biphenyl, 1-naphthyl, 2-naphthyl, 9-anthryl, 9-phenanthryl, 1-pyrenyl, 5-naphthacenyl, 1-indenyl, 2-azulenyl, 9-fluorenyl, biphenylenyl, indacenyl, fluoranthenyl, acenaphthyl, acetothrenyl, phenaltenyl, fluorenyl, anthracenyl, dianthracenyl, trianthryl, tetraanthryl, anthraquinone, phenanthrenyl, benzo[9,10]phenanthrenyl, pyrenyl, The following are examples of the present invention: phenyl, naphthacenyl, pleiadenyl, pyrenyl, perylenyl, pentaphenyl, pentacene, tetraperylene, hexaphenyl, hexaphenyl, rubidenyl, and coronenyl. Among the above, phenyl is preferred.

[0081] Examples of the substituent in the aryl group include an alkyl group, an alkoxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, and a halogen atom (a fluorine atom, a bromine atom, an iodine atom, etc.).

[0082] Examples of the alkyl group in which the hydrogen atom in the aryl group is substituted include the following: 11 ~R 18 The same groups as the unsubstituted alkyl groups represented.

[0083] Examples of the alkoxy group that replaces the hydrogen atom in the aryl group include: 11 ~R 18 The same groups as the unsubstituted alkoxy groups represented.

[0084] Examples of the alkoxycarbonyl group in which the hydrogen atom in the aryl group is substituted include the following: 11 ~R 18 The same groups as the unsubstituted alkoxycarbonyl groups represented.

[0085] Examples of the aryloxycarbonyl group in which the hydrogen atom in the aryl group is substituted include the following: 11 ~R 18 The same groups as the unsubstituted aryloxycarbonyl groups represented.

[0086] In the general formula (1), R 11 ~R 18 The aryloxy group (—O—Ar, where Ar represents an aryl group) represented by can be a substituted or unsubstituted aryloxy group.

[0087] In the general formula (1), R 11 ~R 18 The unsubstituted aryloxy group represented by is preferably an aryloxy group having 6 to 30 carbon atoms, more preferably an aryloxy group having 6 to 14 carbon atoms, and still more preferably an aryloxy group having 6 to 10 carbon atoms.

[0088] Examples of the aryloxy group having 6 to 30 carbon atoms include phenyloxy (phenoxy), biphenyloxy, 1-naphthyloxy, 2-naphthyloxy, 9-anthryloxy, 9-phenanthryloxy, 1-pyrenyloxy, 5-naphthyloxy, 1-indenyloxy, 2-azulenyloxy, 9-fluorenyloxy, biphenylenyloxy, indacenyloxy, fluoranthenyloxy, acenaphthyloxy, acetothrenyloxy, phenanthrenyloxy, fluorenyloxy, anthracenyloxy, dianthracenyloxy, trianthryloxy, tetraanthryloxy, anthraquinoneyloxy, phenanthrenyloxy, benzo[9,10]phenanthrenyloxy, pyrenyloxy, The following are examples of the present invention: 1, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 6

[0089] Examples of the substituent in the aryloxy group include an alkyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, and a halogen atom (a fluorine atom, a bromine atom, an iodine atom, etc.).

[0090] Examples of the alkyl group that replaces the hydrogen atom in the aryloxy group include: 11 ~R 18 The same groups as the unsubstituted alkyl groups represented.

[0091] Examples of the alkoxycarbonyl group in which the hydrogen atom in the aryloxy group is substituted include the following: 11 ~R 18 The same groups as the unsubstituted alkoxycarbonyl groups represented.

[0092] Examples of the aryloxycarbonyl group in which the hydrogen atom in the aryloxy group is substituted include the following: 11 ~R 18 The same groups as the unsubstituted aryloxycarbonyl groups represented.

[0093] In the general formula (1), R 11 ~R 18 The alkoxycarbonyl group (—CO—OR, where R represents an alkyl group) represented by the formula (hereinafter referred to as “alkoxycarbonyl”) may be a substituted or unsubstituted alkoxycarbonyl group.

[0094] In the general formula (1), R 11 ~R 18 The number of carbon atoms in the alkyl chain of the unsubstituted alkoxycarbonyl group represented is preferably 1 to 20, more preferably 1 to 15, and even more preferably 1 to 10.

[0095] Examples of the alkoxycarbonyl group having an alkyl chain with a carbon number of 1 to 20 include methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, n-butoxycarbonyl, sec-butoxybutylcarbonyl, tert-butoxycarbonyl, pentaoxycarbonyl, hexaoxycarbonyl, heptaoxycarbonyl, octaoxycarbonyl, nonaoxycarbonyl, decaoxycarbonyl, dodecaoxycarbonyl, tridecaoxycarbonyl, tetradecaoxycarbonyl, pentadecyloxycarbonyl, hexadecyloxycarbonyl, heptadecaoxycarbonyl, octadecyloxycarbonyl, icosyloxycarbonyl and the like.

[0096] Examples of the substituent in the alkoxycarbonyl group include an aryl group, a hydroxyl group and a halogen atom (a fluorine atom, a bromine atom, an iodine atom, etc.).

[0097] Examples of the aryl group that replaces the hydrogen atom in the alkoxycarbonyl group include the following: 11 ~R 18 The same groups as those represented by the unsubstituted aryl groups.

[0098] In the general formula (1), R 11 ~R 18 The aryloxycarbonyl group (—CO—OAr, Ar represents an aryl group) represented by can be a substituted or unsubstituted aryloxycarbonyl group.

[0099] In the general formula (1), R 11 ~R 18 The number of carbon atoms of the aryl group in the unsubstituted aryloxycarbonyl group represented is preferably 6 or more and 30 or less, more preferably 6 or more and 14 or less, and even more preferably 6 or more and 10 or less.

[0100] Examples of the aryloxycarbonyl group having an aryl group having 6 to 30 carbon atoms include a phenoxycarbonyl group, a biphenyloxycarbonyl group, a 1-naphthyloxycarbonyl group, a 2-naphthyloxycarbonyl group, a 9-anthryloxycarbonyl group, a 9-phenanthrenyloxycarbonyl group, a 1-pyrenyloxycarbonyl group, a 5-naphthacenyloxycarbonyl group, a 1-indenyloxycarbonyl group, a 2-azulenyloxycarbonyl group, a 9-fluorenyloxycarbonyl group, a biphenylenyloxycarbonyl group, an indacenyloxycarbonyl group, a fluoranthenyloxycarbonyl group, an acenaphthyloxycarbonyl group, an acetothrenyloxycarbonyl group, a phenanthrenyloxycarbonyl group, a fluorenyloxycarbonyl group, an anthracenyloxycarbonyl group, a dianthracenyloxycarbonyl group, a trianthryloxycarbonyl group, a tetraanthryloxycarbonyl group, an anthraquinoneyloxycarbonyl group, a phenanthrenyloxycarbonyl group, a benzo[9,10]phenanthrenyloxycarbonyl group, a pyrenyloxycarbonyl group, The following are examples of the present invention: phenoxycarbonyl, ...

[0101] Examples of the substituent in the aryloxycarbonyl group include an alkyl group, a hydroxyl group and a halogen atom (such as a fluorine atom, a bromine atom and an iodine atom).

[0102] Examples of the alkyl group which replaces the hydrogen atom of the aryloxycarbonyl group include the following: 11 ~R 18 The same groups as the unsubstituted alkyl groups represented.

[0103] In the general formula (1), R 11 ~R 18 The alkoxycarbonylalkyl group represented by n H 2n )-CO-OR, R represents an alkyl group, and n represents an integer greater than or equal to 1), and examples thereof include substituted or unsubstituted alkoxycarbonylalkyl groups.

[0104] In the general formula (1), R 11 ~R 18 The alkoxycarbonyl group (-CO-OR) in the unsubstituted alkoxycarbonylalkyl group represented by can be exemplified by the following: 11 ~R 18 The same groups as the alkoxycarbonyl groups represented.

[0105] In the general formula (1), R 11 ~R 18 The alkylene chain (-C n H 2n -), and examples thereof include a linear alkylene chain having 1 to 20 carbon atoms (preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms), a branched alkylene chain having 3 to 20 carbon atoms (preferably 3 to 10 carbon atoms), and a cyclic alkylene chain having 3 to 20 carbon atoms (preferably 3 to 10 carbon atoms).

[0106] Examples of the linear alkylene chain having 1 to 20 carbon atoms include methylene, ethylene, n-propylene, n-butylene, n-pentylene, n-hexylene, n-heptylene, n-octylene, n-nonylene, n-decylene, n-undecylene, n-dodecylene, tridecylene, n-tetradecylene, n-pentadecylene, n-heptadecylene, n-octadecylene, n-nonadecylene and the like.

[0107] Examples of the branched alkylene chain having 3 to 20 carbon atoms include isopropylene, isobutylene, secondary butylene, tertiary butylene, isopentylene, neopentylene, tertiary pentylene, isohexylene, secondary hexylene, tertiary hexylene, isoheptylene, secondary heptylene, tertiary heptylene, isooctylene, secondary octylene, tertiary octylene, isononylene, secondary nonylene, tertiary nonylene, isodecylene, secondary decylene, tertiary decylene, isododecylene, secondary dodecylene, tertiary dodecylene, tertiary tetradecylene, and tertiary pentadecylene.

[0108] Examples of the cyclic alkylene chain having 3 to 20 carbon atoms include cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, cycloheptylene, cyclooctylene, cyclononylene, and cyclodecylene.

[0109] Examples of the substituent in the alkoxycarbonylalkyl group include an aryl group, a hydroxyl group and a halogen atom (such as a fluorine atom, a bromine atom and an iodine atom).

[0110] Examples of the aryl group that replaces the hydrogen atom of the alkoxycarbonylalkyl group include the following: 11 ~R 18 The same groups as those represented by the unsubstituted aryl groups.

[0111] In the general formula (1), R 11 ~R 18 The aryloxycarbonylalkyl group (-(C n H 2n )-CO-OAr, Ar represents an aryl group, and n represents an integer greater than or equal to 1), and examples thereof include substituted or unsubstituted aryloxycarbonylalkyl groups.

[0112] In the general formula (1), R 11 ~R 18 The aryloxycarbonyl group (-CO-OAr, Ar represents an aryl group) in the unsubstituted aryloxycarbonylalkyl group represented by can be exemplified by the group consisting of: 11 ~R 18 The same groups as the aryloxycarbonyl groups represented.

[0113] In the general formula (1), R 11 ~R 18 The alkylene chain (-C n H 2n -), and examples thereof include those having the same 11 ~R 18 The alkylene chain in the alkoxycarbonylalkyl group represented is the same group.

[0114] Examples of the substituent in the aryloxycarbonylalkyl group include an alkyl group, a hydroxy group and a halogen atom (such as a fluorine atom, a bromine atom and an iodine atom).

[0115] Examples of the alkyl group which replaces the hydrogen atom of the aryloxycarbonylalkyl group include the following: 11 ~R 18 The same groups as the unsubstituted alkyl groups represented.

[0116] In the general formula (1), R 11 ~R 18 Examples of the halogen atom represented by include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0117] In the general formula (1), R 11 With R 12 , R 12 With R 13 , R 13 With R 14 , R 15 With R 16 , R 16 With R 17 , or R 17 With R 18 Examples of the ring structure formed by connecting to each other include a benzene ring, a condensed ring having 10 to 18 carbon atoms (naphthalene ring, anthracene ring, phenanthrene ring, 1,2-triphenylene ring (benzo[α]phenanthrene ring), tetracene ring, tetraphenene ring (benzo[α]anthracene ring), benzo[9,10]phenanthrene ring, etc.). Among the above, the ring structure formed is preferably a benzene ring.

[0118] In the general formula (2), R 21 ~R 28 The alkyl group represented by may be any of the following: 11 ~R 18 The same groups as those represented by the alkyl groups.

[0119] In the general formula (2), R 21 ~R 28 The alkoxy group represented by can be exemplified by the following: 11 ~R 18 The same groups as those represented by the alkoxy groups.

[0120] In the general formula (2), R 21 ~R 28 The aralkyl group represented by can be exemplified by the group consisting of the group R 11 ~R 18 The same groups as those represented by the aralkyl groups.

[0121] In the general formula (2), R 21 ~R 28 The aryl group represented by may be the same as R in the general formula (1) 11 ~R 18The same groups as those represented by the aryl groups.

[0122] In the general formula (2), R 21 ~R 28 The aryloxy group represented by can be exemplified by the same group as R in the general formula (1) 11 ~R 18 The same groups as those represented by the aryloxy groups.

[0123] In the general formula (2), R 21 ~R 28 The alkoxycarbonyl group represented by may be exemplified by the group consisting of R 11 ~R 18 The same groups as the alkoxycarbonyl groups represented.

[0124] In the general formula (2), R 21 ~R 28 The aryloxycarbonyl group represented by may be exemplified by the group consisting of 11 ~R 18 The same groups as the aryloxycarbonyl groups represented.

[0125] In the general formula (2), R 21 ~R 28 The alkoxycarbonylalkyl represented by the formula (1) may be any of the following: 11 ~R 18 The same groups as those represented by the alkoxycarbonylalkyl groups.

[0126] In the general formula (2), R 21 ~R 28 The aryloxycarbonylalkyl group represented by can be exemplified by the group consisting of 11 ~R 18 The same groups as those represented by the aryloxycarbonylalkyl group.

[0127] In the general formula (2), R 21 ~R 28 The halogen atom represented by may be any of the following: 11 ~R 18 The halogen atoms represented are the same atoms.

[0128] In the general formula (2), R 21 With R 22 , R 22 With R 23 , R 23 With R 24 , R 25 With R 26 , R 26 With R 27 , or R 27 With R 28Examples of the ring structure formed by connecting to each other include a benzene ring, a condensed ring having 10 to 18 carbon atoms (naphthalene ring, anthracene ring, phenanthrene ring, 1,2-triphenylene ring (benzo[α]phenanthrene ring), tetracene ring, tetraphenene ring (benzo[α]anthracene ring), benzo[9,10]phenanthrene ring, etc.). Among the above, the ring structure formed is preferably a benzene ring.

[0129] In order to further suppress the decrease in photosensitivity and the increase in residual potential caused by repeated image formation, R in the general formula (1) 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 Each independently is preferably a hydrogen atom, an alkyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group or an aryloxycarbonylalkyl group.

[0130] In order to further suppress the decrease in photosensitivity and the increase in residual potential caused by repeated image formation, R in the general formula (2) 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 and R 28 Each independently is preferably a hydrogen atom, an alkyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group or an aryloxycarbonylalkyl group.

[0131] Specific examples of the perionone compound (1) and the perionone compound (2) are shown below, but the present embodiment is not limited thereto. In the following structural formula, Ph represents a phenyl group.

[0132] [Chemistry 3]

[0133]

[0134] [Chemistry 4]

[0135]

[0136] [Chemistry 5]

[0137]

[0138] [Chemistry 6]

[0139]

[0140] [Chemistry 7]

[0141]

[0142] [Chemistry 8]

[0143]

[0144] Violet ketone compound (1) and violet ketone compound (2) are in an isomer relationship (i.e., a cis-isomer and a trans-isomer relationship). As a general synthesis method, 2 moles of o-phenylenediamine compound and 1 mole of naphthalenetetracarboxylic acid compound are heated and condensed to perform synthesis, but a mixture of cis-isomer and trans-isomer is obtained, and the cis-isomer is usually more than the trans-isomer in terms of the mixing ratio. Regarding the separation of the cis-isomer and the trans-isomer, for example, the cis-isomer and the trans-isomer can be separated into a soluble cis-isomer and a poorly soluble trans-isomer by heating and washing with an alcohol solution of potassium hydroxide.

[0145] From the perspective of controlling the volume resistivity of the primer layer within a desired range and film-forming properties, the total content of the perovskite compound (1) and the perovskite compound (2) is preferably 30% by mass or more and 90% by mass or less, more preferably 40% by mass or more and 80% by mass or less, further preferably 45% by mass or more and 75% by mass or less, and still more preferably 50% by mass or more and 70% by mass or less, relative to the total solid content of the primer layer.

[0146] -Metal oxide particles-

[0147] The undercoat layer contains at least one metal oxide particle selected from the group consisting of aluminum oxide particles (also called alumina), iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles, and silicon dioxide particles (also called silica).

[0148] The metal oxide particles may be subjected to surface treatment. Examples of surface treatment agents for the metal oxide particles include silane coupling agents, titanate coupling agents, aluminum coupling agents, surfactants, and the like. The metal oxide particles may be a mixture of two or more metal oxide particles having different metal species, metal oxide particles having different surface treatments, or metal oxide particles having different particle sizes.

[0149] From the perspective of dispersibility in the undercoat layer, the average primary particle size of at least one metal oxide particle selected from the group consisting of aluminum oxide particles, iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles and silicon dioxide particles contained in the undercoat layer is preferably 10 nm or more, more preferably 50 nm or more, further preferably 100 nm or more, further preferably 150 nm or more, further preferably 200 nm or more, and is preferably 1000 nm or less, more preferably 900 nm or less, further preferably 800 nm or less, further preferably 600 nm or less, further preferably 400 nm or less.

[0150] The average primary particle size of the metal oxide particles contained in the undercoat layer is determined by observing the cross section of the undercoat layer using a scanning electron microscope (SEM), measuring the major axis lengths of 100 randomly selected metal oxide particles, and averaging the 100 major axis lengths to determine the average primary particle size.

[0151] From the perspective of suppressing the occurrence of leakage current caused by foreign matter penetration, the total volume of at least one metal oxide particle selected from the group consisting of aluminum oxide particles, iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles, and silicon dioxide particles is preferably 10% by volume or more, more preferably 15% by volume or more, and further preferably 20% by volume or more in the undercoat layer. From the perspective of photosensitivity and suppression of residual potential, the total volume of at least one metal oxide particle selected from the group consisting of aluminum oxide particles, iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles, and silicon dioxide particles is preferably 35% by volume or less, more preferably 30% by volume or less, further preferably 25% by volume or less, further preferably 20% by volume or less, and further preferably 15% by volume or less in the undercoat layer.

[0152] The volume ratio of the metal oxide particles in the undercoat layer can be determined by observing a cross section of the undercoat layer using a scanning electron microscope (SEM) and by the following method.

[0153] In the SEM image, an arbitrary area S is determined for the undercoat layer, and the total area A of the metal oxide particles contained in the area S is calculated. Assuming that the undercoat layer is homogeneous, the value obtained by dividing the total area A of the metal oxide particles by the area S is converted into a percentage (%), which is used as the volume ratio of the metal oxide particles in the undercoat layer. The area S is set to an area that is sufficiently large relative to the size of the metal oxide particles. For example, it is set to a size that includes more than 100 metal oxide particles. The area S may also be the sum of two or more cross sections.

[0154] From the perspective of suppressing the occurrence of leakage current caused by foreign matter penetration, the total content of at least one metal oxide particle selected from the group consisting of aluminum oxide particles, iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles, and silicon dioxide particles is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more relative to the total solid content of the undercoat layer. From the perspective of photosensitivity and suppression of residual potential, the total content of at least one metal oxide particle selected from the group consisting of aluminum oxide particles, iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles, and silicon dioxide particles is preferably less than 30% by mass, more preferably 25% by mass or less, and further preferably 20% by mass or less relative to the total solid content of the undercoat layer.

[0155] From the viewpoint of photosensitivity and suppression of residual potential, the total content of at least one metal oxide particle selected from the group consisting of aluminum oxide particles, iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles and silicon dioxide particles contained in the undercoat layer is preferably 20% by mass or more, more preferably 25% by mass or more, and even more preferably 30% by mass or more, and is preferably 70% by mass or less, more preferably 65% ​​by mass or less, even more preferably 60% by mass or less, and even more preferably 50% by mass or less, relative to the total content of the perolone compound (1) and the perolone compound (2) contained in the undercoat layer.

[0156] - Adhesive resin -

[0157] 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.

[0158] 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).

[0159] Among these, the adhesive resin used in the primer layer is preferably an insoluble resin that is insoluble in the coating solvent of the upper layer, and particularly preferably a thermosetting resin such as a urea resin, a phenol resin, a phenol-formaldehyde resin, a melamine resin, a polyurethane resin, an unsaturated polyester resin, an alkyd resin, an epoxy resin, or a resin obtained by reacting at least one resin selected from the group consisting of a polyamide resin, a polyester resin, a polyether resin, a methacrylic resin, an acrylic resin, a polyvinyl alcohol resin, and a polyvinyl acetal resin with a curing agent. When two or more of these adhesive resins are used in combination, the mixing ratio is set as required.

[0160] As the binder resin used in the primer layer, polyurethane is preferred from the viewpoint of good dispersion of the perirone compound and the metal oxide particles. Polyurethane is generally synthesized by a polyaddition reaction of a polyfunctional isocyanate and a polyol.

[0161] Examples of the polyfunctional isocyanate include diisocyanates such as methylene diisocyanate, ethylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,3-xylylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 3,3'-dimethylbiphenyl diisocyanate, 4,4'-biphenyl diisocyanate, dicyclohexylmethane diisocyanate, and methylenebis(4-cyclohexyl isocyanate); isocyanurates obtained by trimerizing the above diisocyanates; blocked isocyanates obtained by blocking the isocyanate groups of the above diisocyanates with a blocking agent; and the like. The polyfunctional isocyanate may be used alone or in combination of two or more.

[0162] Examples of the polyol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 2,2-dimethyl-1,3-propylene glycol, 1,2-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 2,4-pentanediol, 3,3-dimethyl-1,2-butylene glycol, 2-ethyl-2-methyl-1,3-propylene glycol, 1,2-hexanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, and 2,2-diethyl-1,3-propylene glycol. alcohol, 2,4-dimethyl-2,4-pentanediol, 1,7-heptanediol, 2-methyl-2-propyl-1,3-propanediol, 2,5-dimethyl-2,5-hexanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,4-cyclohexanedimethanol, hydroquinone, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, polypropylene glycol, poly(oxytetramethylene) glycol, 4,4'-dihydroxy-diphenyl-2,2-propane, 4,4'-dihydroxyphenyl sulfone and the like.

[0163] Examples of the polyol further include polyester polyol, polycarbonate polyol, polycaprolactone polyol, polyether polyol, and polyvinyl butyral.

[0164] The polyol may be used alone or in combination of two or more.

[0165] As the urethane curing catalyst (ie, a catalyst for the addition polymerization reaction of a polyfunctional isocyanate and a polyol), a known organic acid metal salt or organic metal complex can be used.

[0166] Of the adhesive resin contained in the primer layer, preferably 80% to 100% by mass of the total amount of the adhesive resin is polyurethane, more preferably 90% to 100% by mass is polyurethane, and further preferably 95% to 100% by mass is polyurethane.

[0167] The undercoat layer may contain various additives in order to improve electrical characteristics, improve environmental stability, and improve image quality.

[0168] 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.

[0169] 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.

[0170] 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.

[0171] 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.

[0172] Examples of the aluminum chelate compound include aluminum isopropionate, monobutoxyaluminum diisopropionate, aluminum butyrate, aluminum diethylacetoacetate diisopropionate, and aluminum tris(ethylacetoacetate).

[0173] These additives may be used alone or in the form of a mixture or polycondensate of two or more compounds.

[0174] From the perspective of suppressing the increase of residual potential when repeatedly forming images, the thickness of the primer layer is 1 μm or more, preferably 2 μm or more, and more preferably 3 μm or more. From the perspective of excellent charge retention of the photoreceptor, the thickness of the primer layer is 10 μm or less, preferably 9 μm or less, and more preferably 8 μm or less.

[0175] The volume resistivity of the primer layer is preferably 1×10 10 Ωcm or more, 1×10 12 Ωcm or less.

[0176] The Vickers hardness of the primer layer may be 35 or higher.

[0177] 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.

[0178] 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.

[0179] The formation of the primer layer is not particularly limited and can be formed by a known formation method. For example, the primer layer can be formed by forming a coating film of a primer layer-forming coating liquid prepared by adding the above components to a solvent, drying the coating film, and heating as needed to form the primer layer.

[0180] 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.

[0181] 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.

[0182] The violacetone compound (1) and the violacetone compound (2) are not easily soluble in an organic solvent, and therefore are preferably dispersed in an organic solvent. Examples of such dispersion methods include known methods such as a roller mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker. The metal oxide particles are also preferably dispersed in an organic solvent using the same dispersion method.

[0183] Examples of a method for applying the coating liquid for forming an undercoat layer onto the conductive substrate include common methods such as blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0184] [Conductive substrate]

[0185] As the conductive substrate, for example, metal plates, metal drums, and metal belts 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, paper, resin films, and belts coated, vapor-deposited, or laminated with conductive compounds (e.g., conductive polymers, indium oxide, etc.), metals (e.g., aluminum, palladium, gold, etc.), or alloys can also be cited. Here, "conductive" means that the volume resistivity is less than 1×10 13 Ωcm.

[0186] Regarding the surface of the conductive substrate, when the 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 for the purpose of suppressing interference fringes generated when irradiating laser. When non-interference light is used as the light source, roughening for preventing interference fringes is not particularly necessary, but the roughening can suppress the occurrence of defects caused by the surface unevenness of the conductive substrate, and is therefore suitable for further extending the life.

[0187] Examples of the roughening method include wet honing in which an abrasive is suspended in water and sprayed onto a support; centerless grinding in which a conductive substrate is pressed against a rotating grindstone to perform a continuous grinding process; and anodizing.

[0188] 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.

[0189] The roughening treatment by anodic oxidation is a roughening treatment in which an oxide film is formed on the surface of the 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 can 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.

[0190] 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.

[0191] The conductive substrate may be subjected to a treatment using an acidic treatment liquid or a boehmite treatment.

[0192] 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: phosphoric acid is in the range of 10 mass % to 11 mass %, chromic acid is in the range of 3 mass % to 5 mass %, and hydrofluoric acid is in the range of 0.5 mass % to 2 mass %, and the overall concentration of these acids is 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.

[0193] 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.

[0194] [Middle layer]

[0195] Although illustration is omitted, an intermediate layer may be further provided between the undercoat layer and the photosensitive layer.

[0196] The intermediate layer is, for example, a layer containing a resin. Examples of the resin used for the intermediate layer include polymer compounds such as 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, and melamine resins.

[0197] 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.

[0198] These compounds for the intermediate layer may be used alone or in the form of a mixture or polycondensate of two or more compounds.

[0199] Among these, the intermediate layer is preferably a layer containing an organic metal compound containing a zirconium atom or a silicon atom.

[0200] 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.

[0201] 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.

[0202] The film thickness of the intermediate layer is preferably set to, for example, a range of 0.1 μm to 3 μm.

[0203] [Charge Generation Layer]

[0204] 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.

[0205] Examples of the charge generating material include azo pigments such as disazo and trisazo; condensed ring aromatic pigments such as dibromobenzopyrene dione alcohol; perylene pigments; pyrrolopyrrole pigments; phthalocyanine pigments; zinc oxide; and trigonal selenium.

[0206] 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.; oxytitanium phthalocyanine disclosed in Japanese Patent Publication No. 4-189873, etc. are more preferred.

[0207] 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 dibromodibenzopyrene dione alcohol; 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.

[0208] 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.

[0209] In contrast, when an n-type semiconductor such as a condensed aromatic pigment, a perylene pigment, or an 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.

[0210] The n-type was determined by using the polarity of the photocurrent flowing using a common time-of-flight method, and the type in which electrons flow more easily as carriers than holes was determined as the n-type.

[0211] 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.

[0212] Examples of the adhesive resin include polyvinyl butyral resin, polyarylate resin (condensation product of bisphenol and aromatic dicarboxylic 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 1×10 13 Ωcm or more.

[0213] These adhesive resins may be used alone or in combination of two or more.

[0214] 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.

[0215] The charge generating layer may contain other known additives.

[0216] The formation of the charge generating layer is not particularly limited, and a known formation method can be used. For example, the charge generating layer can be formed by forming a coating film of a coating liquid for forming a charge generating layer by adding the above-mentioned components to a solvent, drying the coating film, and heating as needed to form the charge generating layer. The charge generating layer can also be formed by vapor deposition of a charge generating material. The formation of the charge generating layer by vapor deposition is particularly suitable for the case where a condensed aromatic pigment or a perylene pigment is used as the charge generating material.

[0217] 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.

[0218] 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.

[0219] During 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.

[0220] Examples of a method for applying the charge generating layer-forming coating liquid onto the undercoat layer (or intermediate layer) include common methods such as blade coating, wire rod coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0221] 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.

[0222] [Charge transport layer]

[0223] 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.

[0224] As charge transport materials, there can be cited quinone compounds such as para-benzoquinone, chloranil, bromoquinone, anthraquinone, etc.; tetracyanobenzoquinone dimethane 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, aryl alkane 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.

[0225] 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.

[0226] [Chemistry 9]

[0227]

[0228] In the structural formula (a-1), Ar T1 ,Ar T2 and Ar T3 Each independently represents a substituted or unsubstituted aryl group, -C6H4-C(R T4 )=C(R T5 )(R T6 ), or -C6H4-CH=CH-CH=C(R T7 )(R T8 ). T4 , R T5 , R T6 , R T7 and R T8Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group.

[0229] 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.

[0230] [Chemistry 10]

[0231]

[0232] 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.

[0233] 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.

[0234] Here, among the triarylamine derivatives represented by the structural formula (a-1) and the benzidine derivatives represented by the structural formula (a-2), the one having "-C6H4-CH=CH-CH=C(R T7 )(R T8 )" and triarylamine derivatives having "-CH=CH-CH=C(R T15 )(R T16 )" benzidine derivatives.

[0235] 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. The polymer charge transport material can be used alone or in combination with a binder resin.

[0236] The adhesive resin for charge transport layer can include 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, polycarbonate resin or polyarylate resin is preferred as the adhesive resin. These adhesive resins are used alone or in combination of two or more.

[0237] The mixing ratio of the charge transport material to the binder resin is preferably 10:1 to 1:5 in terms of mass ratio.

[0238] The charge transport layer may contain other known additives.

[0239] 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.

[0240] 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.

[0241] Examples of the 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.

[0242] 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.

[0243] [Protective layer]

[0244] 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.

[0245] 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).

[0246] 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)

[0247] 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)

[0248] 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], -NH2, -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 Q2 represents a hydrogen atom, an alkyl group, a trialkylsilyl group, Qn represents an integer of 1 to 3] and the like.

[0249] As a 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 vinyl, vinyl ether, vinyl sulfide, styryl (vinyl phenyl), acryloyl, methacryloyl and their derivatives. Among them, for the reason of its excellent reactivity, as a chain polymerizable group, it is preferably a group containing at least one selected from vinyl, styryl (vinyl phenyl), acryloyl, methacryloyl and their derivatives.

[0250] 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 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.

[0251] The reactive group-containing charge transport material, the non-reactive charge transport material, and the reactive group-containing non-charge transport material having a reactive group and a charge transport skeleton may be selected from known materials.

[0252] The protective layer may contain other known additives.

[0253] 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.

[0254] 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.

[0255] The protective layer-forming coating liquid may be a solvent-free coating liquid.

[0256] Examples of a method for applying the protective layer-forming coating liquid onto a photosensitive layer (e.g., charge transport layer) include common methods such as dip coating, extrusion coating, wire bar coating, spray coating, blade coating, knife coating, and curtain coating.

[0257] 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.

[0258] [Single-layer photosensitive layer]

[0259] 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 binder resin and other known additives. These materials are the same as those described for the charge generation layer and the charge transport layer.

[0260] 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.

[0261] 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.

[0262] 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.

[0263] [Image forming apparatus, process cartridge]

[0264] The image forming apparatus of the present embodiment includes: an electrophotographic photoreceptor; a charging unit for charging the surface of the electrophotographic photoreceptor; an electrostatic latent image forming unit for forming an electrostatic latent image on the surface of the charged electrophotographic photoreceptor; a developing unit 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 unit 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.

[0265] The image forming device of this embodiment can apply the following well-known image forming devices: a device equipped with a fixing unit for fixing the toner image transferred to the surface of a recording medium; a device of 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 of 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 unit 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 unit 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.

[0266] In the case of an intermediate transfer method device, the transfer unit, for example, comprises an intermediate transfer body for transferring a toner image on a surface, a primary transfer unit for transferring 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 unit for secondary transferring the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium.

[0267] 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.

[0268] In the image forming apparatus of the present embodiment, for example, the portion having the electrophotographic photoreceptor may be a cartridge structure (processing cartridge) that can be attached and detached from the image forming apparatus. As the processing cartridge, for example, a processing cartridge having the electrophotographic photoreceptor of the present embodiment is suitable for use. In the processing cartridge, in addition to the electrophotographic photoreceptor, for example, at least one selected from the group consisting of a charging unit, an electrostatic latent image forming unit, a developing unit, and a transfer unit may be provided.

[0269] An example of the image forming apparatus according to the present embodiment is shown below, but the present invention is not limited thereto. The main parts shown in the figure will be described, and the description of other parts will be omitted.

[0270] Figure 2 This is a schematic structural diagram showing an example of the image forming apparatus according to the present embodiment.

[0271] like Figure 2 As 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 unit); a transfer device 40 (a primary transfer device); and an intermediate transfer body 50. 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 with the intermediate transfer body 50 interposed therebetween, and the intermediate transfer body 50 is arranged such that a portion of the intermediate transfer body 50 is in contact with the electrophotographic photoreceptor 7. Although not shown in the figure, a secondary transfer device is also provided for transferring the toner image transferred to the intermediate transfer body 50 to a recording medium (e.g., paper). The intermediate transfer body 50, the transfer device 40 (a primary transfer device), and the secondary transfer device (not shown) correspond to an example of a transfer unit.

[0272] Figure 2 The process box 300 in the embodiment integrally supports the electrophotographic photoreceptor 7, the charging device 8 (an example of a charging unit), the developing device 11 (an example of a developing unit), and the cleaning device 13 (an example of a cleaning unit) in a housing. The cleaning device 13 has a cleaning blade (an example of a cleaning member) 131, and the cleaning blade 131 is arranged in a manner to contact the surface of the electrophotographic photoreceptor 7. 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.

[0273] Figure 2In the example, the image forming apparatus includes a fibrous member 132 (rolled) for supplying the lubricant 14 to the surface of the electrophotographic photoreceptor 7 and a fibrous member 133 (flat brush) for assisting cleaning, but these members are arranged as needed.

[0274] Next, each structure of the image forming apparatus according to this embodiment will be described.

[0275] -Charging device-

[0276] 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 corona wire charger or a corotron charger using corona discharge, etc., which are known per se, can also be used.

[0277] -Exposure device-

[0278] As the exposure device 9, for example, there can be cited an optical device that uses semiconductor laser, LED light, liquid crystal shutter light and other light to expose the surface of the electrophotographic photoreceptor 7 according to a determined image. The wavelength of the light source is set within the spectral sensitivity region of the electrophotographic photoreceptor. As the wavelength of the semiconductor laser, near-infrared with an oscillation wavelength near 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 perform color imaging, a surface-emitting laser source that can output multiple beams is also effective.

[0279] -Developing device-

[0280] As the developing device 11, for example, a common 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 known developer having a function of attaching a single-component developer or a two-component developer to the electrophotographic photoreceptor 7 using a brush, a roller, etc. can be cited. Among them, it is preferable to use a developing roller having a developer retained on the surface.

[0281] 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.

[0282] -Cleaning device-

[0283] The cleaning device 13 is a cleaning blade type device including a cleaning blade 131 .

[0284] In addition to the cleaning blade method, you can also use a brush cleaning method and a simultaneous development cleaning method.

[0285] -Transfer device-

[0286] 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 corona wire transfer charger using corona discharge, and a corotron transfer charger.

[0287] -Intermediate transfer body-

[0288] 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.

[0289] Figure 3 This is a schematic structural diagram showing another example of the image forming apparatus according to the present embodiment.

[0290] Figure 3 The 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. The image forming apparatus 120 has the same structure as the image forming apparatus 100 except that it is a tandem type.

[0291] Example

[0292] The following examples are given to more specifically illustrate the electrophotographic photoreceptor of the present invention. The materials, dosages, proportions, processing procedures, etc. shown in the following examples may be appropriately changed without departing from the purpose of the present invention. Therefore, the scope of the electrophotographic photoreceptor of the present invention should not be interpreted in a restrictive manner by the specific examples shown below.

[0293] <Production of Photoreceptor>

[0294] [Example 1]

[0295] (Formation of Primer Layer)

[0296] 21 parts by mass of blocked isocyanate (Sumidur BL3175, manufactured by Sumitomo-Bayer Urethane Co., Ltd., solid content 75% by mass), 9 parts by mass of butyral resin (S-LECBL-1, manufactured by Sekisui Chemical Co., Ltd.) and 0.005 parts by mass of dioctyltin dilaurate as a urethane curing catalyst were dissolved in 143 parts by mass of methyl ethyl ketone. 50 parts by mass of a mixture of purple ketone compound (1-3) and purple ketone compound (2-3) (mass ratio 1:1) and 20 parts by mass of alumina particles (EM Japan Co., Ltd., average primary particle size 200 nm) were mixed in the solution, and dispersed for 120 minutes using a sand mill using glass beads with a diameter of 1 mm to obtain a coating liquid for forming a primer layer. The coating liquid was dip-coated on a cylindrical aluminum substrate, dried and cured at 160°C for 60 minutes to form a primer layer with a thickness of 5.0 μm.

[0297] (Formation of Charge Generation Layer)

[0298] As a charge generating material, hydroxygallium phthalocyanine is prepared, which has diffraction peaks at Bragg angles (2θ±0.2°) of at least 7.3°, 16.0°, 24.9°, and 28.0° in an X-ray diffraction spectrum using Cukα characteristic X-rays. 15 parts by mass of hydroxygallium phthalocyanine, 10 parts by mass of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nippon Unicar Co., Ltd.) and 200 parts by mass of n-butyl acetate are mixed, and the resulting mixture is dispersed using a sand mill with glass beads having a diameter of 1 mm for 4 hours. 175 parts by mass of n-butyl acetate and 180 parts by mass of methyl ethyl ketone are added to the resulting dispersion, and stirred to obtain a coating solution for forming a charge generating layer. The coating solution is dip-coated on the undercoat layer and dried at room temperature (25°C) to form a charge generating layer having a thickness of 0.2 μm.

[0299] (Formation of Charge Transport Layer)

[0300] In a flask equipped with a phosgene blowing tube, a thermometer and a stirrer, 106.9 g (0.398 mol) of 1,1-bis(4-hydroxyphenyl)cyclohexane (hereinafter referred to as Z), 24.7 g (0.133 mol) of 4,4'-dihydroxybiphenyl (hereinafter referred to as BP), 0.41 g of hydrogen sulfite, 825 ml of 9.1% sodium hydroxide aqueous solution (2.018 mol of sodium hydroxide) and 500 ml of dichloromethane were added and dissolved under a nitrogen atmosphere, and 76.2 g (0.770 mol) of phosgene was blown in for 75 minutes while maintaining the temperature at 18°C ​​to 21°C under stirring to carry out a phosgenation reaction. After the phosgenation reaction was terminated, 1.11 g (0.0075 mol) of p-tert-butylphenol and 54 ml (0.266 mol of sodium hydroxide) of 25% aqueous solution were added and stirred, and 0.18 mL (0.0013 mol) of triethylamine was added during the reaction, and the mixture was reacted at a temperature of 30°C to 35°C for 2.5 hours. The separated dichloromethane phase was washed with acid and water until inorganic salts and amines disappeared, and then dichloromethane was removed to obtain a polycarbonate copolymer (1). In the polycarbonate copolymer (1), the structural unit ratio of Z to BP was 75:25 in terms of molar ratio, and the viscosity average molecular weight was 50,000.

[0301] 25 parts by mass of N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1']biphenyl-4,4'-diamine (TPD), 20 parts by mass of the compound represented by the following structural formula (A), and 55 parts by mass of a polycarbonate copolymer (1) as a binder resin were added to 560 parts by mass of tetrahydrofuran and 240 parts by mass of toluene for dissolution to obtain a coating liquid for a charge transport layer. The coating liquid was applied to the charge generating layer and dried at 135°C for 45 minutes to form a charge transport layer with a thickness of 22 μm. The photoreceptor of Example 1 was obtained by the above treatment.

[0302] [Chemistry 11]

[0303]

[0304] [Examples 2 to 17]

[0305] In forming the undercoat layer, a photoreceptor was prepared in the same manner as in Example 1 except that the type and amount of the perirone compound, the type and amount of the metal oxide particles, or the thickness of the undercoat layer were changed as described in Table 1.

[0306] The average primary particle size of the iron oxide particles used in Example 2 was 250 nm (manufactured by Corefront Co., Ltd.).

[0307] The copper oxide particles used in Example 3 had an average primary particle size of 100 nm (manufactured by Japan-Ion Corporation).

[0308] The average primary particle size of the magnesium oxide particles used in Example 4 was 100 nm (manufactured by Ion-Ceramic Co., Ltd.).

[0309] The average primary particle size of the calcium oxide particles used in Example 5 was 150 nm (manufactured by Ohmi Mining Co., Ltd.).

[0310] The average primary particle size of the silica particles used in Example 6 was 200 nm (manufactured by Corefront Co., Ltd.).

[0311] [Example 18]

[0312] A photoreceptor was prepared in the same manner as in Example 1 except that the binder resin in forming the primer layer was changed from polyurethane to polyethylene (NEO-ZEX manufactured by PRIME POLYMER CO., LTD.).

[0313] [Comparative Examples 1 to 3]

[0314] A photoreceptor was prepared in the same manner as in Example 1 except that the perinone compound was replaced with an imide compound listed in Table 1 in forming the undercoat layer. The chemical structures of the imide compound (A), the imide compound (B), or the imide compound (C) used in Comparative Examples 1 to 3 are shown below.

[0315] [Chemistry 12]

[0316]

[0317] [Comparative Example 4]

[0318] A photoreceptor was prepared in the same manner as in Example 1 except that the metal oxide particles were not used in forming the undercoat layer.

[0319] [Comparative Example 5]

[0320] A photoreceptor was prepared in the same manner as in Example 1 except that the thickness of the undercoat layer was changed as described in Table 1.

[0321] [Comparative Examples 6 to 9]

[0322] In forming the undercoat layer, a photoreceptor was prepared in the same manner as in Example 1 except that the metal oxide particles were changed to other particles as described in Table 1.

[0323] The zinc oxide particles used in Comparative Example 6 were obtained by surface-treating untreated zinc oxide particles (average primary particle size 70 nm, MZ-150 manufactured by TAYCA) with a silane coupling agent (3-methacryloxypropylmethyldiethoxysilane, KBE-502 manufactured by Shin-Etsu Chemical Co., Ltd.).

[0324] The titanium oxide particles used in Comparative Example 7 had an average primary particle size of 30 nm (TAF-1500J manufactured by Fuji Titanium Industry).

[0325] The average primary particle size of the tin oxide particles used in Comparative Example 8 was 20 nm (S1 manufactured by Mitsubishi Materials).

[0326] The average primary particle size of the iron particles used in Comparative Example 9 was 100 nm (manufactured by JFE Steel Corporation).

[0327] <Performance Evaluation of Photoreceptor>

[0328] The photoreceptors of the examples or comparative examples were installed in an image forming apparatus Docucentre-V C7775 manufactured by Fuji Xerox Co., Ltd., and the following performance evaluation was performed in an environment of a temperature of 40° C. and a relative humidity of 90%.

[0329] [Charge Sustainability]

[0330] A surface potential probe of a surface potentiometer (manufactured by Trek, Trek 334) was set at a position 1 mm away from the surface of the photoreceptor.

[0331] After the surface of the photoreceptor was charged to -700 V, the potential reduction amount (dark decay rate) after 0.1 second was measured, and the potential reduction amount was classified into the following four levels.

[0332] A+: The potential drop is less than 20V.

[0333] A: The potential drop is 20V or more and less than 25V.

[0334] B: The potential drop is 25 V or more and less than 50 V.

[0335] C: The potential drop is 50 V or more.

[0336] [Suppression of leakage current generation]

[0337] When the carbon fibers penetrate the photosensitive layer and the primer layer to reach the conductive substrate, current flows and dot-shaped image defects are generated. This phenomenon is used to evaluate the suppression of leakage current generation.

[0338] A developer was mixed with carbon fibers (average diameter 7 μm, average length 120 μm) at 0.1% by mass relative to the developer amount, and 30,000 black images with an image density of 15% were continuously output on A4 paper. The 30,000th image was visually observed for dot-shaped image defects, and the degree of image defects was classified into the following grades A to C.

[0339] A+: There are less than 5 dot-shaped image defects.

[0340] A: The number of dot-like image defects is 5 or more and less than 10.

[0341] B: The number of dot-like image defects is 10 or more and less than 20.

[0342] C: There are 20 or more dot-like image defects.

[0343] [Residual potential during repeated imaging]

[0344] A surface potential probe of a surface potentiometer (manufactured by Trek, Trek 334) was set at a position 1 mm away from the surface of the photoreceptor.

[0345] The surface of the photoreceptor was charged to -700 V, and the residual potential after charge removal was measured.

[0346] The above measurement was performed before and after outputting 80,000 images with a density of 20% on A4 paper. The residual potential difference was calculated by subtracting the residual potential before output from the residual potential after output. The residual potential difference before and after output was classified into the following grades A+ to C.

[0347] A+: The residual potential difference before and after output is less than 20V.

[0348] A: The residual potential difference before and after output is greater than 20V and less than 50V.

[0349] B: The residual potential difference before and after output is 50V or more and less than 100V.

[0350] C: The residual potential difference before and after output is 100V or more.

[0351]

[0352] [Explanation of Symbols]

[0353] 1 undercoat layer, 2 charge generating layer, 3 charge transport layer, 4 conductive substrate, 5 photosensitive layer, 7A electrophotographic photoreceptor, 7 electrophotographic photoreceptor, 8 charging device, 9 exposure device, 11 developing device, 13 cleaning device, 14 lubricant, 40 transfer device, 50 intermediate transfer body, 100 image forming device, 120 image forming device, 131 cleaning blade, 132 fibrous member (rolled), 133 fibrous member (flat brush), 300 process box.

Claims

1. An electrophotographic photoreceptor comprising a conductive substrate, an undercoat layer disposed on the conductive substrate, and a photosensitive layer disposed on the undercoat layer, The thickness of the primer layer is not less than 1 μm and not more than 10 μm. The above-mentioned base coating contains: A compound represented by the following general formula (1); A compound represented by the following general formula (2); at least one metal oxide particle selected from the group consisting of aluminum oxide particles, iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles, and silicon dioxide particles; and Adhesive resin, [Chemistry 1] In the general formula (1), R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom; R 11 With R 12 , R 12 With R 13 and R 13 With R 14 Each independently does not form a ring or is linked to each other to form a ring; R 15 With R 16 , R 16 With R 17 and R 17 With R 18 Each independently does not form a ring or is linked to each other to form a ring; In the general formula (2), R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 and R 28 each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom; R 21 With R 22 , R 22 With R 23 and R 23 With R 24 Each independently does not form a ring or is linked to each other to form a ring; R 25 With R 26 , R 26 With R 27 and R 27 With R 28 They may not form a ring independently or may be linked to each other to form a ring.

2. The electrophotographic photoreceptor according to claim 1, wherein The average primary particle size of the at least one metal oxide particle is 10 nm or more and 1000 nm or less.

3. The electrophotographic photoreceptor according to claim 1 or claim 2, wherein: The total content of the at least one metal oxide particle contained in the undercoat layer is 20 mass % or more and 70 mass % or less relative to the total content of the compound represented by the general formula (1) and the compound represented by the general formula (2) contained in the undercoat layer.

4. The electrophotographic photoreceptor according to claim 1 or claim 2, wherein: The total volume of the at least one metal oxide particle accounts for 10 volume % or more and 35 volume % or less in the undercoat layer.

5. The electrophotographic photoreceptor according to claim 1 or claim 2, wherein The total content of the compound represented by the general formula (1) and the compound represented by the general formula (2) is 50% by mass or more and 70% by mass or less based on the total solid content of the primer layer.

6. The electrophotographic photoreceptor according to claim 1 or claim 2, wherein: The adhesive resin includes polyurethane. 7 . A process cartridge detachable from an image forming apparatus, comprising the electrophotographic photoreceptor according to claim 1 .

8. An image forming apparatus comprising: The electrophotographic photoreceptor according to any one of claims 1 to 6; A charging unit for charging the surface of the electrophotographic photoreceptor; An electrostatic latent image forming unit for forming an electrostatic latent image on the surface of the charged electrophotographic photoreceptor; a developing unit 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; as well as The transfer unit transfers the toner image onto a surface of a recording medium.

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