Electrophotographic photoreceptor, process cartridge and image formation device

Abstract

To provide an electrophotographic photoreceptor which suppresses peeling of a surface protective layer from a charge transport layer.SOLUTION: An electrophotographic photoreceptor has a conductive substrate, a charge generating layer provided on the conductive substrate, a charge transport layer provided on the charge generating layer, and a surface protective layer provided on the charge transport layer, wherein the charge transport layer has film thickness of 8 μm or more and 25 μm or less, and the surface protective layer has film thickness of 10 μm or less, and is a cured film of a composition which contains a resin (X) having at least one of a unit represented by a specific formula (X1) and a unit represented by a specific formula (X2), and a reactive group-containing charge transport material having a reactive group and a charge transporting skeleton in the same molecule.SELECTED DRAWING: None

Description

[Technical field]

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

[0002] Patent Document 1 discloses an image forming apparatus in which "the surface of a photoconductor charged by a charging section is exposed to light to form an electrostatic latent image on the photoconductor, the electrostatic latent image formed is developed to form a toner image, the toner image on the photoconductor is then transferred to a transfer medium, and the surface of the photoconductor after transfer is cleaned with a cleaning member, wherein the charging section employs a contact charging method that comes into contact with the surface of the photoconductor, the photoconductor has a protective layer on its photosensitive layer that is harder than the photosensitive layer, and the cleaning member is a metallic cleaning blade whose tip comes into contact with the surface of the photoconductor."

[0003] Patent Document 2 discloses a "composition for forming an overcoat layer of an organic photoreceptor, characterized by containing a polyaminoether and a solvent."

[0004] Patent Document 3 discloses a "coating composition for forming an overcoat layer of an organic photoreceptor, characterized in that it contains a polyaminoether, an electron transport material, and an alcohol-based solvent." [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-161668 A [Patent Document 2] JP 2004-139022 A [Patent Document 3] JP 2004-133470 A Summary of the Invention [Problem to be solved by the invention]

[0006] In a conventional electrophotographic photoreceptor having a laminated type photosensitive layer and a surface protective layer, the surface protective layer may peel off from the charge transport layer. An object of the present disclosure is to provide an electrophotographic photoreceptor in which peeling of the surface protective layer from the charge transport layer is suppressed compared to when the thickness of the charge transport layer exceeds 25 μm or when the thickness of the surface protective layer exceeds 10 μm. [Means for solving the problem]

[0007] Specific means for solving the above problems include the following aspects.

[0008] <1> A conductive substrate; a charge generating layer provided on the conductive substrate; a charge transport layer disposed on the charge generating layer; a surface protective layer provided on the charge transport layer; having The charge transport layer has a thickness of 8 μm or more and 25 μm or less, The surface protective layer has a thickness of 10 μm or less, and is a cured film of a composition including a resin (X) having at least one of a unit represented by the following formula (X1) and a unit represented by the following formula (X2), and a reactive group-containing charge transport material having a reactive group and a charge transport skeleton in the same molecule: Electrophotographic photoreceptor. [ka] In formula (X1), R 101 , R 102 and R 103 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; L 101 represents a single bond, an alkylene group having from 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof; L 102 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof; R104 and R 105 are each independently an alkyl group having 1 to 5 carbon atoms, n is an integer of 0 to 300, R 106 , R 107 and R 108 are each independently an alkyl group having 1 to 5 carbon atoms, or -O-[Si(R 109 )(R 110 )O] m -Si(R 111 )(R 112 )(R 113 ) and R 109 , R 110 , R 111 , R 112 and R 113 each independently represents an alkyl group having 1 to 5 carbon atoms, and m is an integer of 0 to 20. In formula (X2), R 201 , R 202 and R 203 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; L 201 represents a single bond, an alkylene group having from 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof; L 202 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof; R 204 is an alkyl group having 6 to 30 carbon atoms. <2> The thickness T of the charge transport layer CT (μm) and the thickness T of the surface protective layer OVC (μm) ratio (T CT / T OVC ) is 1.42 or more and 25 or less, <1> The electrophotographic photoreceptor according to claim 1. <3> The charge transport layer has a thickness of 8 μm or more and 20 μm or less. <1> The electrophotographic photoreceptor according to claim 1. <4> The charge transport layer has a thickness of 9 μm or more and 20 μm or less. <3> The electrophotographic photoreceptor according to claim 1. <5> The thickness of the surface protective layer is 1 μm or more and 10 μm or less. <1> The electrophotographic photoreceptor according to claim 1. <6> The thickness of the surface protective layer is 5 μm or more and 9 μm or less. <5> The electrophotographic photoreceptor according to claim 1. <7> The above <1> ~ <6> The electrophotographic photoreceptor according to any one of the above items is provided, A process cartridge that is detachably attached to an image forming apparatus. <8> The above <1> ~ <6> and an electrophotographic photoreceptor according to any one of the above items. a charging device for charging a surface of the electrophotographic photoreceptor; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the electrophotographic photoreceptor; The electrostatic latent image formed on the surface of the electrophotographic photoreceptor is developed with a developer containing a toner. a developing device for forming a toner image by using the toner; a transfer device for transferring the toner image onto a surface of a recording medium; An image forming apparatus comprising: <9> The transfer device is An intermediate transfer belt; a blade that comes into contact with an outer peripheral surface of the intermediate transfer belt and cleans the outer peripheral surface; a primary transfer device having a primary transfer member for primarily transferring a toner image formed on a surface of an image carrier onto an outer peripheral surface of the intermediate transfer belt at a linear pressure of 17 g / cm or less; a secondary transfer device that is disposed in contact with an outer peripheral surface of the intermediate transfer belt and has a secondary transfer member that secondarily transfers the toner image transferred onto the outer peripheral surface of the intermediate transfer belt onto a surface of a recording medium; The above <8> 2. The image forming apparatus according to claim 1 . Effect of the Invention

[0009] <1> According to the present invention, an electrophotographic photoreceptor is provided in which peeling of the surface protective layer from the charge transport layer is suppressed compared to when the thickness of the charge transport layer exceeds 25 μm or when the thickness of the surface protective layer exceeds 10 μm. <2> According to the present invention, the thickness T CT (μm) and the thickness T of the surface protective layer OVC (μm) ratio (T CT / T OVC) exceeds 25, peeling of the surface protective layer from the charge transport layer is suppressed. <3> According to the present invention, there is provided an electrophotographic photoreceptor in which peeling of the surface protective layer from the charge transport layer is suppressed, as compared with the case where the thickness of the charge transport layer is less than 8 μm or exceeds 20 μm. <4> According to the present invention, there is provided an electrophotographic photoreceptor in which peeling of the surface protective layer from the charge transport layer is suppressed, as compared with the case where the thickness of the charge transport layer is less than 9 μm or exceeds 20 μm. <5> According to the present invention, there is provided an electrophotographic photoreceptor in which peeling of the surface protective layer from the charge transport layer is suppressed, as compared with the case where the thickness of the surface protective layer is less than 1 μm or exceeds 10 μm. <6> According to the present invention, there is provided an electrophotographic photoreceptor in which peeling of the surface protective layer from the charge transport layer is suppressed, as compared with the case where the thickness of the surface protective layer is less than 5 μm or exceeds 9 μm.

[0010] <7> or <8> According to the invention, there is provided a process cartridge or an image forming apparatus equipped with an electrophotographic photoreceptor in which peeling of the surface protective layer from the charge transport layer is suppressed compared to when an electrophotographic photoreceptor is equipped with an electrophotographic photoreceptor whose charge transport layer thickness exceeds 25 μm or when an electrophotographic photoreceptor is equipped with an electrophotographic photoreceptor whose surface protective layer thickness exceeds 10 μm. <9> According to the invention, The present invention provides an image forming apparatus having an electrophotographic photosensitive member in which peeling of a surface protective layer from a charge transport layer is suppressed compared to a case in which the transfer device includes an intermediate transfer belt, a blade that comes into contact with the outer peripheral surface of the intermediate transfer belt and cleans the outer peripheral surface, a primary transfer device having a primary transfer member that primarily transfers a toner image formed on the surface of an image carrier to the outer peripheral surface of the intermediate transfer belt at a transfer pressure of more than 17 g / cm, and a secondary transfer device having a secondary transfer member that is arranged in contact with the outer peripheral surface of the intermediate transfer belt and secondarily transfers the toner image transferred to the outer peripheral surface of the intermediate transfer belt to the surface of a recording medium. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a partial cross-sectional view showing an example of a layer structure of the electrophotographic photoreceptor according to the first embodiment. [Diagram 2] 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a schematic configuration diagram illustrating another example of an image forming apparatus according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the present disclosure will be described. These descriptions and examples are merely illustrative of the embodiments, and are not intended to limit the scope of the embodiments.

[0013] In the present disclosure, a numerical range indicated using "~" indicates a range that includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described in the present disclosure in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit value of the numerical range may be replaced with a value shown in the examples.

[0014] In the present disclosure, the term "step" includes not only an independent step, but also a step that cannot be clearly distinguished from other steps as long as the purpose of the step is achieved.

[0015] When an embodiment of the present disclosure is described with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. In addition, the size of the members in each drawing is conceptual, and the relative relationship between the sizes of the members is not limited to this.

[0016] In the present disclosure, each component may contain multiple types of corresponding substances. When referring to the amount of each component in a composition in the present disclosure, if multiple substances corresponding to each component are present in the composition, the total amount of the multiple substances present in the composition is meant unless otherwise specified. In the present disclosure, the particles corresponding to each component may include multiple types. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified.

[0017] In the present disclosure, unless otherwise specified, the alkyl group and the alkylene group include any of straight-chain, branched, and cyclic groups.

[0018] In the present disclosure, a hydrogen atom in an organic group, an aromatic ring, a linking group, an alkyl group, an alkylene group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, and the like may be substituted with a halogen atom.

[0019] In the present disclosure, a polymer that does not have a siloxane skeleton in the main chain, but has a siloxane skeleton in a branch portion (that is, a graft chain) is referred to as a "graft-type polysiloxane compound". In the present disclosure, a polymer that does not have a siloxane skeleton in its main chain and has long-chain alkyl groups in its branches (i.e., graft chains) is referred to as a "graft-type long-chain alkyl resin." In the present disclosure, a polymer having a siloxane skeleton in the main chain is referred to as a "straight-type polysiloxane compound."

[0020] <Electrophotographic photoreceptor> The electrophotographic photoreceptor according to the present embodiment has a conductive substrate, a charge generating layer provided on the conductive substrate, a charge transport layer provided on the charge generating layer, and a surface protective layer provided on the charge transport layer, in which the charge transport layer has a thickness of 8 μm or more and 25 μm or less, and the surface protective layer has a thickness of 10 μm or less, and is a cured film of a composition containing a resin (X) having at least one of a unit represented by the following formula (X1) and a unit represented by the following formula (X2), and a reactive group-containing charge transport material having a reactive group and a charge transport skeleton in the same molecule.

[0021] [ka] In formula (X1), R 101 , R 102 and R 103 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; L 101 represents a single bond, an alkylene group having from 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof; L 102 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof; R 104 and R 105 are each independently an alkyl group having 1 to 5 carbon atoms, and n is an integer of 0 to An integer between 300 and R 106 , R 107 and R 108 are each independently an alkyl group having 1 to 5 carbon atoms, or -O-[Si(R 109 )(R 110 )O] m -Si(R 111 )(R 112 )(R 113 ) and R 109 , R 110 , R 111 , R 112 and R 113 each independently represents an alkyl group having 1 to 5 carbon atoms, and m is an integer of 0 to 20. In formula (X2), R 201 , R 202 and R 203 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; L 201 represents a single bond, an alkylene group having from 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof; L 202 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof; R 204 is an alkyl group having 6 to 30 carbon atoms.

[0022] Conventionally, in electrophotographic photoreceptors, a technique is known in which a surface protective layer, which is a cured film of a composition, is provided on a photosensitive layer in order to improve the lifespan (so-called wear life) of the photoreceptor due to wear and to maintain image quality stability. However, photoreceptors having a surface protective layer, which is a cured film of a conventional composition, tend to have coating defects such as excessive moisture or air bubbles being mixed into the coating film or coating unevenness occurring during the process of forming the surface protective layer. Therefore, streaky image defects are likely to occur in areas where coating defects occur. As a result of intensive research, the present inventors have found that in a photoreceptor having the above-mentioned surface protective layer, coating defects in the surface protective layer can be suppressed by including resin (X) in the cured film. Specifically, since resin (X) is a graft-type polysiloxane compound or a graft-type long-chain alkyl resin, it is easier to ensure adequate wettability during the formation of the surface protective layer and has excellent film-forming properties compared to conventional straight-type polysiloxane compounds. In addition, coating unevenness is suppressed even during curing accompanied by volume shrinkage during drying of the coating. As a result, it is believed that streak-like image defects caused by coating defects are suppressed. However, in an electrophotographic photoreceptor having a surface protective layer containing the resin (X) in the cured film, during transfer from this electrophotographic photoreceptor, depending on the load applied to the interface between the charge transport layer and the surface protective layer, peeling of the surface protective layer from the charge transport layer may occur due to a reaction against the load. In response to this, the present inventors have found, as a result of further intensive research, that by setting the film thickness of the surface protective layer and the charge transport layer to the above-mentioned thickness, i.e., a film thickness that is relatively thinner than conventional thicknesses, the load applied to the interface between the charge transport layer and the surface protective layer is reduced even during transfer from this electrophotographic photosensitive member, and peeling of the surface protective layer from the charge transport layer is suppressed.

[0023] In the present disclosure, the term "peeling of the surface protective layer from the charge transport layer" is a concept that also encompasses lifting or chipping of the surface protective layer from the charge transport layer.

[0024] Fig. 1 is a partial cross-sectional view showing an example of the layer structure of a photoreceptor according to the present embodiment. The photoreceptor 10A shown in Fig. 1 has a laminated photosensitive layer. The photoreceptor 10A has a structure in which an undercoat layer 2, a charge generation layer 3, and a charge transport layer 4 are laminated in this order on a conductive substrate 1, and the charge generation layer 3 and the charge transport layer 4 constitute a photosensitive layer 5 (a so-called function-separated photosensitive layer). The photoreceptor 10A may have an intermediate layer (not shown) between the undercoat layer 2 and the charge generation layer 3.

[0025] Each layer of the photoreceptor will be described in detail below, with the reference numerals omitted.

[0026] The charge transport layer has a thickness of 8 μm or more and 25 μm or less, preferably 8 μm or more and 20 μm or less, and more preferably 9 μm or more and 20 μm or less. When the thickness of the charge transport layer is 8 μm or more, the load imbalanced between the charge transport layer and the surface protective layer, which causes a reaction to the load applied to the interface between the charge transport layer and the surface protective layer, is reduced, and peeling of the surface protective layer from the charge transport layer is more suppressed. Also, the charge transport performance is easily ensured. Also, when the thickness is less than 8 μm, it may be difficult to retain charges. When the thickness of the charge transport layer is 25 μm or less, the reaction to a load applied to the interface between the charge transport layer and the surface protective layer is reduced, and peeling of the surface protective layer from the charge transport layer is further suppressed.

[0027] The method for adjusting the thickness of the charge transport layer to the above range is not particularly limited, but may be, for example, a method for adjusting the coating speed of a coating liquid for forming the charge transport layer.

[0028] The thickness of the charge transport layer is determined as follows. The surface protective layer is peeled off from the electrophotographic photoreceptor, and the thickness of the exposed charge transport layer is measured at any 10 points from the outer peripheral surface side using a dielectric thickness measuring device (Fischer Instruments, FISCHERSCOPE MMS). The arithmetic mean value of each value is taken as the thickness of the charge transport layer.

[0029] The surface protective layer has a thickness of 10 μm or less, preferably from 1 μm to 10 μm, and more preferably from 5 μm to 9 μm. If the surface protective layer is thicker than 10 μm, the residual charge on the photoreceptor increases, making it difficult to form an image, so the surface protective layer is preferably 10 μm or less. When the thickness of the surface protective layer is 1 μm or more, the load imbalanced between the charge transport layer and the surface protective layer, and the reaction of the load applied to the interface between the charge transport layer and the surface protective layer is reduced, and the peeling of the surface protective layer from the charge transport layer is further suppressed. In addition, the life due to wear of the photoreceptor (so-called wear life) is improved and the image quality stability is excellent.

[0030] The method for adjusting the thickness of the surface protective layer to the above range is not particularly limited, and examples thereof include a method of adjusting the coating speed of the coating liquid for forming the surface protective layer.

[0031] The thickness of the surface protective layer is determined as follows. A portion of the surface protective layer is peeled off from the electrophotographic photoreceptor. Then, the thickness from the outer peripheral surface of the surface protective layer to the outer peripheral surface of the exposed charge transport layer is measured at any 10 points using a dielectric film thickness measuring device (Fischer Instruments, FISCHERSCOPE MMS). The arithmetic average of each value is taken as the film thickness of the surface protective layer. When measuring the film thickness of the surface protective layer, the measurement is performed on a sample coated with only the protective layer.

[0032] The electrophotographic photoreceptor according to this embodiment has a thickness T CT (μm) and the thickness of the surface protection layer T OVC (μm) ratio (T CT / T OVC ) is preferably 1.42 or more and 25 or less, and more preferably 1.42 or more and 1.85 or less.

[0033] ratio(T CT / T OVCWhen the ratio (R) is 1.42 or less, the thickness of the surface protective layer is too thin relative to the thickness of the charge transport layer, which reduces the occurrence of a backlash in the load applied to the interface between the charge transport layer and the surface protective layer due to an imbalance in the loads applied to the charge transport layer and the surface protective layer, and thus further suppresses peeling of the surface protective layer from the charge transport layer. ratio(T CT / T OVC When the ratio is 25 or more, the thickness of the surface protective layer is too large relative to the thickness of the charge transport layer, which reduces the occurrence of a backlash in the load applied to the interface between the charge transport layer and the surface protective layer due to an imbalance in the loads applied to the charge transport layer and the surface protective layer, thereby further suppressing peeling of the surface protective layer from the charge transport layer.

[0034] [Surface protective layer] The surface protective layer is a layer having a thickness of 10 μm or less and made of a cured film of a composition containing a resin (X) having at least one of a unit represented by the following formula (X1) and a unit represented by the following formula (X2), and a reactive group-containing charge transport material having a reactive group and a charge transport skeleton in the same molecule (i.e., a layer containing a polymer or crosslinked product of the reactive group-containing charge transport material). The composition may contain other materials such as a curing agent and a leveling agent as necessary.

[0035] [Resin (X)] The resin (X) has at least one of the units (X1) and the units (X2). The resin (X) may contain other structural units in addition to the units (X1) and the units (X2). Resin (X) contains at least one of units (X1) and (X2) and is a graft polymer having a siloxane chain or a long-chain alkyl group on the side chain. This makes it easier to ensure adequate wettability during the formation of a surface protective layer, and provides excellent film-forming properties. In addition, coating film unevenness is suppressed even during curing, which is accompanied by volume shrinkage during drying of the coating film. As a result, streaks caused by coating film defects are prevented. Thus, image defects such as the above-mentioned can be suppressed.

[0036] The unit (X1) is a structural unit represented by the following formula (X1).

[0037] [ka]

[0038] In formula (X1), R 101 , R 102 and R 103 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; L 101 represents a single bond, an alkylene group having from 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof; L 102 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof; R 104 and R 105 are each independently an alkyl group having 1 to 5 carbon atoms, n is an integer of 0 to 300, R 106 , R 107 and R 108 are each independently an alkyl group having 1 to 5 carbon atoms, or -O-[Si(R 109 )(R 110 )O] m -Si(R 111 )(R 112 )(R 113 ) and R 109 , R 110 , R 111 , R 112 and R 113 each independently represents an alkyl group having 1 to 5 carbon atoms, and m is an integer of 0 to 20.

[0039] R 101 , R 102 and R 103 The alkyl group having 1 to 5 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 to 4, more preferably 1 to 3, further preferably 1 or 2, and particularly preferably 1.

[0040] R 101 and R 102are each independently preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0041] R 103 is preferably a hydrogen atom or a methyl group.

[0042] L 101 and L 102 The alkylene group having 1 to 5 carbon atoms may be linear, branched, or cyclic. The alkylene group preferably has 2 to 5 carbon atoms, more preferably 2 to 4 carbon atoms, and even more preferably 3 carbon atoms. Examples of the linear alkylene group having 1 to 5 carbon atoms include a methylene group, an ethylene group, an n-propylene group, an n-butylene group, and an n-pentylene group. Examples of the branched alkylene group having 3 to 5 carbon atoms include an isopropylene group, an isobutylene group, a sec-butylene group, a tert-butylene group, an isopentylene group, a neopentylene group, and a tert-pentylene group. Examples of the cyclic alkylene group having 3 to 5 carbon atoms include a cyclopropylene group, a cyclobutylene group, and a cyclopentylene group.

[0043] L 101 The aromatic ring of the aromatic ring which may have a substituent according to the above may be either a monocyclic ring or a polycyclic ring. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring, and the benzene ring and the naphthalene ring are preferred. The hydrogen atoms of the aromatic ring may be substituted by alkyl groups, aryl groups, aralkyl groups, alkoxy groups, or aliphatic groups. The aromatic ring may be substituted with an aryloxy group, a halogen atom, etc. When the aromatic ring is substituted, the substituent is preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and further preferably a methyl group.

[0044] L 101is preferably -C(=O)O- or an aromatic ring which may have a substituent, more preferably -C(=O)O- or a benzene ring which may have a substituent, and even more preferably -C(=O)O- or a benzene ring.

[0045] L 102 is preferably a single bond, a linear alkylene group having from 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof, and more preferably a linear alkylene group having from 2 to 4 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof.

[0046] R 104 and R 105 The alkyl group having 1 to 5 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 to 4, more preferably 1 to 3, further preferably 1 or 2, and particularly preferably 1.

[0047] R 104 and R 105 are each independently preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 4 carbon atoms, and further preferably a methyl group.

[0048] n is an integer of 0 or more and 300 or less, preferably an integer of 1 or more and 250 or less, more preferably an integer of 3 or more and 200 or less, and even more preferably an integer of 5 or more and 150 or less.

[0049] R 106 , R 107 , R 108 , R 109 , R 110 , R 111 , R 112 and R 113 The alkyl group having 1 to 5 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 to 4, more preferably 1 to 3, further preferably 1 or 2, and particularly preferably 1.

[0050] R 106 , R 107 and R 108 When each of are independently an alkyl group having 1 to 5 carbon atoms, it is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 4 carbon atoms, and further preferably a methyl group.

[0051] R 109 , R 110 , R 111 , R 112 and R 113 are each independently preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 4 carbon atoms, and further preferably a methyl group.

[0052] m is an integer of 0 or more and 20 or less, preferably an integer of 0 or more and 15 or less, more preferably an integer of 0 or more and 10 or less, and even more preferably an integer of 0 or more and 5 or less.

[0053] The unit (X1) is preferably at least one of a unit (X1-1) represented by the following formula (X1-1) and a unit (X1-2) represented by the following formula (X1-2).

[0054] [ka]

[0055] In formula (X1-1) and formula (X1-2), R 103 is a hydrogen atom or a methyl group, and L 102 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof, n is an integer of 0 to 300, R 106 , R 107 and R 108 are each independently an alkyl group having 1 to 5 carbon atoms, or -O-[Si(R 109 )(R 110 )O]m -Si(R 111 )(R 112 )(R 113 ) and R 109 , R 110 , R 111 , R 112 and R 113 each independently represents an alkyl group having 1 to 5 carbon atoms, and m is an integer of 0 to 20.

[0056] R in formula (X1-1) and formula (X1-2) 103 , n, R 106 , R 107 , R 108 , R 109 , R 110 , R 111 , R 112 , R 113 and m are R in formula (X1), 103 , n, R 106 , R 107 , R 108 , R 109 , R 110 , R 111 , R 112 , R 113 and m have the same meanings and preferred embodiments.

[0057] L in formula (X1-1) 102 is preferably a straight-chain alkylene group having 1 to 5 carbon atoms, or a combination of a straight-chain alkylene group having 1 to 5 carbon atoms and -O-, more preferably a straight-chain alkylene group having 2 to 4 carbon atoms or a combination of a straight-chain alkylene group having 2 to 4 carbon atoms and -O-, and even more preferably a straight-chain alkylene group having 2 or 3 carbon atoms, or a combination of a straight-chain alkylene group having 2 or 3 carbon atoms and -O-. L 102 Of the atoms forming the formula (X1-1), the number of atoms connecting "O" of -C(=O)O- and "Si" of -(Si(CH3)2O)n- in the shortest distance is preferably 1 or more and 5 or less, more preferably 2 or more and 4 or less, and even more preferably 3 or 4.

[0058] L in formula (X1-2)102 is preferably a linear alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof, more preferably a linear alkylene group having 1 to 4 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof, and even more preferably a linear alkylene group having 1 to 3 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof. L 102 Of the atoms forming the formula (X1-2), the number of atoms connecting the benzene ring in formula (X1-2) and "Si" in -(Si(CH3)2O)n- at the shortest distance is preferably 1 or more and 7 or less, more preferably 1 or more and 6 or less, and even more preferably 1 or more and 5 or less.

[0059] Specific examples of the unit (X1-1) are shown below, but the unit (X1-1) is not limited to these: Me is a methyl group, and n-Bu is a normal butyl group.

[0060] [ka]

[0061] [ka]

[0062] Specific examples of the unit (X1-2) are shown below, but the unit (X1-2) is not limited to these: Me is a methyl group, and n-Bu is a normal butyl group.

[0063] [ka]

[0064] Specific examples of the unit (X1) other than the unit (X1-1) and the unit (X1-2) are shown below, but the unit (X1) is not limited thereto. Me is a methyl group, Et is an ethyl group, and Ph is a phenyl group.

[0065] [ka]

[0066] The unit (X2) is a structural unit represented by the following formula (X2).

[0067] [ka]

[0068] In formula (X2), R 201 , R 202 and R 203 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; L 201 represents a single bond, an alkylene group having from 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof; L 202 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof; R 204 is an alkyl group having 6 to 30 carbon atoms.

[0069] R 201 , R 202 and R 203 The alkyl group having 1 to 5 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 to 4, more preferably 1 to 3, further preferably 1 or 2, and particularly preferably 1.

[0070] R 201 and R 202 are each independently preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0071] R 203 is preferably a hydrogen atom or a methyl group.

[0072] L 201 and L 202The alkylene group having 1 to 5 carbon atoms may be linear, branched, or cyclic. The alkylene group preferably has 2 to 5 carbon atoms, more preferably 2 to 4 carbon atoms, and even more preferably 3 carbon atoms. Examples of the linear alkylene group having 1 to 5 carbon atoms include a methylene group, an ethylene group, an n-propylene group, an n-butylene group, and an n-pentylene group. Examples of the branched alkylene group having 3 to 5 carbon atoms include an isopropylene group, an isobutylene group, a sec-butylene group, a tert-butylene group, an isopentylene group, a neopentylene group, and a tert-pentylene group. Examples of the cyclic alkylene group having 3 to 5 carbon atoms include a cyclopropylene group, a cyclobutylene group, and a cyclopentylene group.

[0073] L 201 The aromatic ring of the aromatic ring which may have a substituent according to the above may be either a monocyclic ring or a polycyclic ring. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring, and the benzene ring and the naphthalene ring are preferred. The hydrogen atoms of the aromatic ring may be substituted with an alkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a halogen atom, etc. When the aromatic ring is substituted, the substituent is preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and further preferably a methyl group.

[0074] L 201 is preferably -C(=O)O- or an aromatic ring which may have a substituent, more preferably -C(=O)O- or a benzene ring which may have a substituent, and even more preferably -C(=O)O- or a benzene ring.

[0075] L 202 is preferably a single bond, a linear alkylene group having 1 to 4 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof, More preferably, it is one to three straight-chain alkylene groups, -O-, -C(=O)-, -C(=O)O-, or a combination thereof.

[0076] R 204 The alkyl group having 6 to 30 carbon atoms may be linear, branched, or cyclic, and is preferably linear or branched. The number of carbon atoms in the alkyl group is preferably 8 to 28, more preferably 9 to 26, and even more preferably 10 to 25. Examples of the linear alkyl group having 6 to 30 carbon atoms include an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-heptadecyl group, an n-octadecyl group, an n-nonadecyl group, an n-icosyl group, and an n-docosyl group. Examples of branched alkyl groups having 6 to 30 carbon atoms include an isohexyl group, a sec-hexyl group, a tert-hexyl group, an isoheptyl group, a sec-heptyl group, a tert-heptyl group, an isooctyl group, a sec-octyl group, a tert-octyl group, an isononyl group, a sec-nonyl group, a tert-nonyl group, an isodecyl group, a sec-decyl group, a tert-decyl group, an isododecyl group, a sec-dodecyl group, a tert-dodecyl group, a tert-tetradecyl group, and a tert-pentadecyl group. Examples of the cyclic alkyl group having 6 to 30 carbon atoms include a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, and polycyclic (e.g., bicyclic, tricyclic, spirocyclic) alkyl groups formed by linking these monocyclic alkyl groups.

[0077] R 204 is preferably a linear or branched alkyl group having 6 to 30 carbon atoms, more preferably a linear or branched alkyl group having 8 to 28 carbon atoms, even more preferably a linear or branched alkyl group having 9 to 26 carbon atoms, and even more preferably a linear or branched alkyl group having 10 to 25 carbon atoms.

[0078] The unit (X2) is preferably at least one of a unit (X2-1) represented by the following formula (X2-1) and a unit (X2-2) represented by the following formula (X2-2).

[0079] [ka]

[0080] In formula (X2-1) and formula (X2-2), R 203 is a hydrogen atom or a methyl group, and L 202 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof; R 204 is an alkyl group having 6 to 30 carbon atoms.

[0081] R in formula (X2-1) and formula (X2-2) 203 and R 204 are R in formula (X2), 203 , L 202 and R 204 The same definition and preferred form are also the same.

[0082] L in formula (X2-1) 202 is preferably a single bond.

[0083] L in formula (X2-2) 202 is preferably a single bond, a linear alkylene group having 1 to 4 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof, and more preferably a single bond, a linear alkylene group having 1 to 3 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof. L 202 Among the atoms forming the benzene ring and R in formula (X2-2), 204 The number of atoms connecting them at the shortest distance is preferably 1 or more and 5 or less, more preferably 1 or more and 3 or less, and even more preferably 1 or 2.

[0084] Specific examples of the unit (X2-1) are shown below, but the unit (X2-1) is not limited to these: Me is a methyl group.

[0085] [ka]

[0086] [ka]

[0087] Specific examples of the unit (X2-2) are shown below, but the unit (X2-2) is not limited thereto.

[0088] [ka]

[0089] Specific examples of the unit (X2) other than the unit (X2-1) and the unit (X2-2) are shown below, but the unit (X2) is not limited thereto.

[0090] [ka]

[0091] The resin (X) preferably contains both a unit represented by the formula (X1) and a unit represented by the formula (X2). By containing both of the above two units, and also because the wettability of the resin (X) is appropriately maintained, when a coating liquid containing the resin (X) is applied in the manufacturing process of the surface protective layer, coating defects caused by air bubbles in the coating film due to the viscosity of the coating liquid becoming too high, or unevenness in the coating film due to the viscosity of the coating liquid becoming too low, are further suppressed.

[0092] It is preferable that the resin (X) further contains a unit represented by the following formula (X3): By further containing the unit represented by the formula (X3), the wettability of the resin (X) is appropriately maintained, and therefore, when a coating liquid containing the resin (X) is applied in the manufacturing process of the surface protective layer, defects in the coating film caused by bubbles being generated in the coating film due to the viscosity of the coating liquid becoming too high, or unevenness in the coating film caused by the viscosity of the coating liquid becoming too low, are further suppressed. JPEG2025054812000015.jpg4566 In formula (X3), R 301 , R 302 and R 303 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; L 301 represents an alkylene group having 3 to 10 carbon atoms which may have a substituent.

[0093] R 301 , R 302 and R 303 The alkyl group having 1 to 5 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 to 4, more preferably 1 to 3, further preferably 1 or 2, and particularly preferably 1. R 301 , R 302 and R 303 are each independently preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0094] L 301 The alkylene group having 3 to 10 carbon atoms may be linear, branched, or cyclic. The alkylene group preferably has 3 to 8 carbon atoms, more preferably 3 to 6 carbon atoms, and even more preferably 3 to 5 carbon atoms.

[0095] Examples of the linear alkylene group having 3 to 10 carbon atoms include an n-propylene group, an n-butylene group, an n-pentylene group, an n-hexylene group, an n-heptylene group, an n-octylene group, an n-nonylene group, and an n-decanylene group. Examples of branched alkylene groups having 3 to 10 carbon atoms include an isopropylene group, an isobutylene group, a sec-butylene group, a tert-butylene group, an isopentylene group, a neopentylene group, a tert-pentylene group, a 2-propylpropylene group, a 2-butylpropylene group, a 2-ethylpropylene group, a 2-methylpropylene group, a 1-ethyl-2-methylpropylene group, a 1-propyl-2-methylpropylene group, a 1-methyl-2-ethylpropylene group, a 1-propylpropylene group, a 1-butylpropylene group, and a 2-methylpentylene group. Examples of the cyclic alkylene group having 3 to 10 carbon atoms include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, a cyclooctylene group, a cyclononylene group, and a cyclodecanylene group.

[0096] Specific examples of the unit (X3) are shown below, but the unit (X3) is not limited thereto.

[0097] [ka]

[0098] The unit (X1) contained in the resin (X) may be of one type or of two or more types. The unit (X2) contained in the resin (X) may be of one type or of two or more types. The unit (X3) contained in the resin (X) may be of one type or of two or more types.

[0099] Resin (X) may contain other structural units in addition to units (X1), (X2), and (X3). Hereinafter, such other structural units are referred to as units (X4). Unit (X4) may be of one type or of two or more types.

[0100] Examples of the unit (X4) include a unit derived from a styrene-based monomer and a unit derived from an acrylic monomer.

[0101] Examples of styrene monomers include styrene, vinylnaphthalene; α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, Examples of the styrene-substituted styrene include lower alkyl-substituted styrenes such as 2,4-dimethylstyrene, p-n-butylstyrene, and p-tert-butylstyrene; aryl-substituted styrenes such as p-phenylstyrene; lower alkoxy-substituted styrenes such as p-methoxystyrene; and halogen-substituted styrenes such as p-chlorostyrene, 3,4-dichlorostyrene, p-fluorostyrene, and 2,5-difluorostyrene.

[0102] Examples of acrylic monomers include (meth)acrylic acid; (meth)acrylic acid lower alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)methacrylate, and n-pentyl (meth)acrylate; benzyl (meth)acrylate, etc. The term "(meth)acrylic" means that it can mean either "acrylic" or "methacrylic".

[0103] Examples of the unit (X4) include units derived from the following monomers: Olefins such as isoprene, butene, and butadiene; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; and vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, and vinyl isopropenyl ketone.

[0104] The unit (X4) is preferably at least one selected from the group consisting of units derived from styrene, units derived from (meth)acrylic acid, and units derived from a lower alkyl (meth)acrylate, more preferably at least one selected from the group consisting of units derived from styrene and units derived from a lower alkyl (meth)acrylate, and even more preferably at least one selected from the group consisting of units derived from styrene, units derived from methyl (meth)acrylate, and units derived from ethyl (meth)acrylate.

[0105] The total content of the units (X1), (X2) and (X3) contained in the resin (X) is preferably 10 mol % to 95 mol %, more preferably 15 mol % to 90 mol %, and even more preferably 20 mol % to 80 mol %. In other words, the content of the unit (X3) in the resin (X) is preferably 5 mol % or more and 90 mol % or less, more preferably 10 mol % or more and 85 mol % or less, and even more preferably 20 mol % or more and 80 mol % or less.

[0106] From the viewpoints of improving the life span of the photoreceptor and image quality stability due to wear, the mass proportion of the resin (X) in the surface protective layer is preferably from 0.01% to 10.00% by mass, more preferably from 0.01% to 5% by mass, and even more preferably from 0.1% to 1% by mass. The mass proportion of the resin (X) in the surface protective layer may be 0.01 mass % or more and 0.30 mass % or less. It is known that when a lubricant such as a conventional straight polysiloxane compound is added to a reactive cured film, the mass ratio of the lubricant in the surface protective layer is 0.30 mass% or more to ensure wettability. On the other hand, since the resin (X) in this embodiment has at least one of a unit represented by formula (X1) and a unit represented by formula (X2), it is easier to obtain wettability with a small amount compared to conventional lubricants, and the compatibility is also high. Therefore, in the photoreceptor according to this embodiment, even within the above-mentioned range of 0.01 mass% or more and 0.30 mass% or less, streaky image defects caused by coating defects occurring in the manufacturing process of the surface protective layer are suppressed.

[0107] When the mass ratio of the resin (X) is 0.01 mass% or more, the wettability of the surface protective layer is easily ensured, and thus coating defects are further suppressed. When the mass ratio of the resin (X) is 0.30 mass% or less, coating defects caused by air bubbles in the coating film due to the viscosity of the coating liquid containing the resin (X) becoming too high due to an excessive proportion of the resin (X) during coating in the manufacturing process of the surface protective layer are further suppressed.

[0108] The weight average molecular weight of the resin (X) is preferably 1,000 or more and 30,000 or less, more preferably 1,000 or more and 10,000 or less, and even more preferably 1,000 or more and 8,000 or less. When the weight average molecular weight of the resin (X) is 1000 or more, the wettability of the surface protective layer is easily ensured, and thus coating defects are further suppressed. When the weight average molecular weight of the resin (X) is 30,000 or less, when a coating liquid containing the resin (X) is applied in the production process of the surface protective layer, the viscosity of the coating liquid becomes too high, and thus coating film defects caused by air bubbles in the coating film can be further suppressed. The molecular weight of the resin (X) is a molecular weight measured in terms of polystyrene by gel permeation chromatography (GPC). GPC is measured by a conventional method using tetrahydrofuran or chloroform as an eluent, for example.

[0109] The method for producing the resin (X) includes chain polymerization of a monomer that gives the unit (X1), a monomer that gives the unit (X2), and a monomer that gives the unit (X3). Examples of the chain polymerization method include radical polymerization, coordination polymerization, and ionic polymerization (cationic polymerization, anionic polymerization). Among these, radical polymerization is preferred from the viewpoint of versatility such as polymerization control and range of application.

[0110] [Reactive group-containing charge transport material] The reactive group of the reactive group-containing charge transport material may be a chain polymerizable group, an epoxy group, -OH, -OR (wherein R represents an alkyl group), -NH2, -SH, -COOH, or -SiR. Q1 3-Qn (OR Q2 ) Qn (However, 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, or a trialkylsilyl group; Qn represents an integer of 1 to 3).

[0111] The chain polymerizable group is not particularly limited as long as it is a functional group capable of radical polymerization, and is, for example, a functional group having a group containing at least a carbon double bond.Specific examples include a group containing at least one selected from a vinyl group, a vinyl ether group, a vinyl thioether group, a styryl group (phenylvinyl group), an acryloyl group, a methacryloyl group, and derivatives thereof.Among them, the chain polymerizable group is preferably a group containing at least one selected from a vinyl group, a styryl group (phenylvinyl group), an acryloyl group, a methacryloyl group, and derivatives thereof, because of its excellent reactivity.

[0112] The charge transporting skeleton of the reactive group-containing charge transporting material is not particularly limited as long as it is a known structure in electrophotographic photoreceptors, and examples thereof include a skeleton derived from a nitrogen-containing hole transporting compound such as a triazine-based compound, a triarylamine-based compound, a benzidine-based compound, a hydrazone-based compound, etc., and a structure conjugated with a nitrogen atom. Among these, from the viewpoint of charge transporting performance, a skeleton derived from at least one of a triarylamine-based compound and a triazine-based compound is preferred.

[0113] The reactive group-containing charge transport material may be selected from well-known materials. The reactive group-containing charge transport material may be of one type or of two or more types.

[0114] The reactive group-containing charge transport material preferably includes at least one reactive group-containing charge transport material having at least one substituent selected from the group consisting of -OH, -OCH3, -NH2, -SH, and -COOH (hereinafter also referred to as "specific charge transport material"). The cured film of the composition containing the specific charge transport material is less likely to generate residual OH or water in the film, and is less susceptible to the influence of moisture in the air when forming the coating film. Therefore, the cured film of the composition containing these compounds is more suppressed in coating film defects and more suppressed in streaky image defects when forming the surface protective layer.

[0115] (Specific charge transport material) The specific charge transport material refers to a charge transport material having at least one substituent selected from the group consisting of -OH, -OCH3, -NH2, -SH, and -COOH. From the viewpoint of making it difficult for residual OH groups and the like to occur in the film and also making it difficult for the coating film to be affected by moisture in the air during film formation, and further suppressing coating film defects, it is more preferable that the specific charge transport material is a charge transport material having at least one of the substituents -OCH3 and -SH.

[0116] The specific charge transporting material is preferably a compound represented by the following general formula (I) from the viewpoint of suppressing wear of the foreign matter removing member and suppressing wear of the electrophotographic photosensitive member.

[0117] F-((-R 13 -X) n1 (R 14 ) n2 -Y) n3 (I)

[0118] In the general formula (I), F is an organic group derived from a compound having a hole transporting ability, R 13 and R 14 each independently represents a linear or branched alkylene group having 1 to 5 carbon atoms, n1 represents 0 or 1, n2 represents 0 or 1, and n3 represents an integer of 1 to 4. X represents an oxygen, NH, or sulfur atom, and Y represents -OH, -OCH3, -NH2, -SH, or -COOH. In the general formula (I), the compound having a hole transporting ability in the organic group derived from the compound having a hole transporting ability represented by F is preferably an arylamine derivative. As the arylamine derivative, preferably, a triphenylamine derivative and a tetraphenylbenzidine derivative are exemplified. The compound represented by general formula (I) is preferably a compound represented by the following general formula (II): The compound represented by general formula (II) is particularly excellent in charge mobility, stability against oxidation, etc.

[0119] [ka]

[0120] In general formula (II), Ar 1 From Ar 4 may be the same or different and each independently represents a substituted or unsubstituted aryl group; Ar 5 represents a substituted or unsubstituted aryl group or a substituted or unsubstituted arylene group, and D represents -(-R 13 -X) n1 (R 14 ) n2 -Y, c is independently 0 or 1, k is 0 or 1, and the total number of D is 1 or more and 4 or less. 13 and R 14 each independently represents a linear or branched alkylene group having 1 to 5 carbon atoms; n1 represents 0 or 1; n2 represents 0 or 1; X represents an oxygen, NH, or sulfur atom; Y represents -OH, -OCH3, -NH2, -SH, or indicates -COOH. In the general formula (II), "-(-R 13 -X) n1 (R 14 ) n2 -Y" is the same as in general formula (I), and R 13 and R 14 are each independently a linear or branched alkylene group having 1 to 5 carbon atoms. n1 is preferably 1. n2 is preferably 1. X is preferably oxygen. Y is preferably a hydroxyl group. The total number of Ds in general formula (II) corresponds to n3 in general formula (I) and is preferably 2 or more and 4 or less, and more preferably 3 or more and 4 or less. In general formula (I) or (II), when the total number of Ds in one molecule is 2 to 4, preferably 3 to 4, the crosslinking density increases, making it easier to obtain a crosslinked membrane with higher strength.

[0121] In the general formula (II), Ar1 to Ar4 are preferably any one of the following formulas (1) to (7). In addition, the following formulas (1) to (7) each include "-(D)" which can be linked to each of Ar1 to Ar4. C " is shown.

[0122] [ka]

[0123] In equations (1) to (7), R 15 represents one member selected from the group consisting of a hydrogen atom, an alkyl group having from 1 to 4 carbon atoms, a phenyl group substituted with an alkyl group having from 1 to 4 carbon atoms or an alkoxy group having from 1 to 4 carbon atoms, an unsubstituted phenyl group, and an aralkyl group having from 7 to 10 carbon atoms; R 16 From R 18 each represents one member selected from the group consisting of a hydrogen atom, an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, a phenyl group substituted with an alkoxy group having from 1 to 4 carbon atoms, an unsubstituted phenyl group, an aralkyl group having from 7 to 10 carbon atoms, and a halogen atom; Ar represents a substituted or unsubstituted arylene group; D and c are the same as “D” and “c” in general formula (II); s each represents 0 or 1; and t represents an integer of 1 to 3.

[0124] Ar in the formula (7) is preferably represented by the following formula (8) or (9).

[0125] [ka]

[0126] In equations (8) to (9), R 19 and R 20 each represents one member selected from the group consisting of a hydrogen atom, an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, a phenyl group substituted with an alkoxy group having from 1 to 4 carbon atoms, an unsubstituted phenyl group, an aralkyl group having from 7 to 10 carbon atoms, and a halogen atom, and t represents an integer of 1 to 3.

[0127] Z' in formula (7) is preferably represented by any one of the following formulas (10) to (17).

[0128] [ka]

[0129] In equations (10) to (17), R 21 and R 22 each represents one selected from the group consisting of a hydrogen atom, an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms or a phenyl group substituted with an alkoxy group having from 1 to 4 carbon atoms, an unsubstituted phenyl group, an aralkyl group having from 7 to 10 carbon atoms, and a halogen atom; W represents a divalent group; q and Each r represents an integer of 1 or more and 10 or less, and each t represents an integer of 1 or more and 3 or less.

[0130] W in the formulae (16) and (17) is preferably any one of the divalent groups represented by the following (18) to (26), where u in the formula (25) represents an integer of 0 to 3.

[0131] [ka]

[0132] In general formula (II), Ar 5 When k is 0, Ar 1 From Ar 4 When k is 1, it is an arylene group formed by removing a hydrogen atom from any of the aryl groups (1) to (7).

[0133] Specific examples of the compound represented by formula (I) are shown below, but the compound represented by formula (I) is not limited to these in any way.

[0134] [ka]

[0135] [ka]

[0136] [ka]

[0137] [ka]

[0138] [ka]

[0139] [ka]

[0140] [ka]

[0141] The total content of the specific charge transporting material (solid content concentration in the coating liquid) is preferably 90% by mass or more, more preferably 94% by mass or more. When the solid content concentration is 90% by mass or more, the deterioration of electrical properties is suppressed.

[0142] [Hardening agent] The surface protective layer may be a layer formed of a cured film of a composition further containing a curing agent in addition to the resin (X) and the reactive group-containing charge transport material. The curing agent may be one type or two or more types.

[0143] Examples of the curing agent include an isocyanate compound, a polyol, a guanamine compound, a melamine compound, etc. Among the above, the curing agent preferably contains at least one compound selected from a compound having a guanamine structure (hereinafter also referred to as a "guanamine compound") and a compound having a melamine structure (hereinafter also referred to as a "melamine compound"). The cured film of the composition containing at least one compound selected from guanamine compound and melamine compound as a curing agent is less likely to generate residual OH or water in the film, and is less susceptible to the influence of moisture in the air when forming the coating film.Therefore, the cured film of the composition containing these compounds is more suppressed in coating film defects when forming a surface protective layer, and streaky image defects are also more suppressed.In addition, it is easy to obtain a cured film with a high degree of curing, and it has excellent abrasion resistance.

[0144] In particular, the surface protective layer preferably contains a resin (X), at least one of a guanamine compound and a melamine compound curing agent, and at least one reactive group-containing charge transport material (hereinafter also referred to as a "specific charge transport material") having at least one substituent selected from the group consisting of -OH, -OCH3, -NH2, -SH, and -COOH. The cured film of the composition containing the resin (X), at least one of the curing agents of the guanamine compound and the melamine compound, and the specific charge transport material is unlikely to generate residual OH or water in the film, and is also unlikely to be affected by moisture in the air when the coating film is formed. Therefore, when the composition containing these compounds is used as the cured film, coating film defects are more suppressed when the surface protective layer is formed, and streaky image defects are also more suppressed.

[0145] (Guanamine compounds) The guanamine compound is a compound having a guanamine skeleton (structure), and examples thereof include acetoguanamine, benzoguanamine, formoguanamine, steroguanamine, spiroguanamine, and cyclohexylguanamine. The guanamine compound is preferably at least one of the compounds represented by the following general formula (A) and their multimers. Here, the multimer is an oligomer polymerized with the compound represented by the general formula (A) as a structural unit, and has a degree of polymerization of, for example, 2 to 200 (preferably 2 to 100). The compound represented by the general formula (A) may be used alone or in combination of two or more. In particular, when the compound represented by the general formula (A) is used in combination of two or more, or as a multimer (oligomer) having the compound represented by the general formula (A) as a structural unit, the solubility in a solvent is improved.

[0146] [ka]

[0147] In the general formula (A), R1 represents a linear or branched alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, or a substituted or unsubstituted alicyclic hydrocarbon group having 4 to 10 carbon atoms. R2 to R5 each independently represent a hydrogen atom. , -CH2-OH, or -CH2-O-R6, where R6 represents a linear or branched alkyl group having 1 to 10 carbon atoms. In the general formula (A), the alkyl group represented by R1 has a carbon number of 1 to 10, preferably 1 to 8 and more preferably 1 to 5. The alkyl group may be linear or branched. In the general formula (A), the phenyl group represented by R1 has a carbon number of 6 or more and 10 or less, more preferably 6 or more and 8 or less. Examples of the substituent substituted on the phenyl group include a methyl group, an ethyl group, and a propyl group. In the general formula (A), the alicyclic hydrocarbon group represented by R1 has a carbon number of 4 to 10, more preferably 5 to 8. Examples of the substituent substituted on the alicyclic hydrocarbon group include a methyl group, an ethyl group, and a propyl group. In the general formula (A), in "-CH2-O-R6" representing R2 to R5, the alkyl group representing R6 has a carbon number of 1 to 10, preferably 1 to 8 or more, and more preferably 1 to 6. The alkyl group may be linear or branched. Preferred examples include a methyl group, an ethyl group, and a butyl group.

[0148] Particularly preferred compounds represented by general formula (A) are those in which R1 represents a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, and R2 to R5 each independently represent -CH2-O-R6. R6 is preferably selected from a methyl group or an n-butyl group. The compound represented by the general formula (A) can be synthesized, for example, using guanamine and formaldehyde by a known method (for example, Jikken Kagaku Koza, 4th ed., Vol. 28, p. 430, edited by the Chemical Society of Japan). Below, exemplary compounds (A)-1 to (A)-42 are shown as specific examples of the compound represented by general formula (A), but the present embodiment is not limited to these. In addition, the following specific examples are monomers, but may be polymers (oligomers) having these monomers as structural units. In the following exemplary compounds, "Me" represents a methyl group, "Bu" represents a butyl group, and "Ph" represents a phenyl group.

[0149] [ka]

[0150] [ka]

[0151] [ka]

[0152] [ka]

[0153] In addition, examples of commercially available products of the compound represented by general formula (A) include Super Beckamine(R) L-148-55, Super Beckamine(R) 13-535, Super Beckamine(R) L-145-60, Super Beckamine(R) TD-126 (all manufactured by Dainippon Ink Co., Ltd.), Nikalac BL-60, and Nikalac BX-4000 (all manufactured by Nippon Carbide Corporation). After synthesis or after purchasing a commercially available product, the compound represented by general formula (A) (including polymers) may be dissolved in a suitable solvent such as toluene, xylene, ethyl acetate, etc., and washed with distilled water, ion-exchanged water, etc., or may be treated with an ion-exchange resin to remove the influence of residual catalyst.

[0154] (Melamine compounds) The melamine compound has a melamine skeleton (structure), and is preferably at least one of the compounds represented by the following general formula (B) and their multimers. Here, the multimer is an oligomer polymerized with the compound represented by the general formula (B) as a structural unit, similar to the general formula (A), and has a degree of polymerization of, for example, 2 to 200 (preferably 2 to 100). The compound represented by the general formula (B) or its multimer may be used alone or in combination of two or more. It may also be used in combination with the compound represented by the general formula (A) or its multimer. In particular, when the compound represented by the general formula (B) is used in a mixture of two or more or as a multimer (oligomer) having the compound represented by the general formula (B) as a structural unit, the solubility in a solvent is improved.

[0155] [ka]

[0156] In general formula (B), R 6 From R 11 are each independently a hydrogen atom, -CH2-OH, -CH2-OR 12 , -OR 12 R 12represents an alkyl group having 1 to 5 carbon atoms which may be branched. Examples of the alkyl group include a methyl group, an ethyl group, and a butyl group. The compound represented by the general formula (B) is synthesized, for example, by a known method using melamine and formaldehyde (for example, synthesized in the same manner as the melamine resin described in Experimental Chemistry Lectures, 4th Edition, Vol. 28, p. 430). As specific examples of the compound represented by the general formula (B), the following exemplary compounds (B)-1 to (B)-8 are shown below, but the present embodiment is not limited thereto. The following specific examples are monomers, but may be polymers (oligomers) having these as structural units.

[0157] [ka]

[0158] Examples of commercially available products of the compound represented by general formula (B) include Super Melami No. 90 (manufactured by Nippon Oil & Fats Co., Ltd.), Super Beckamin® TD-139-60 (manufactured by Dainippon Ink Co., Ltd.), U-Ban 2020 (manufactured by Mitsui Chemicals, Inc.), Sumitex Resin M-3 (manufactured by Sumitomo Chemical Co., Ltd.), and Nikalac MW-30 (manufactured by Nippon Carbide Corporation). Furthermore, after synthesis or after purchasing a commercially available product, the compound represented by general formula (B) (including polymers) may be dissolved in a suitable solvent such as toluene, xylene, ethyl acetate, etc., and washed with distilled water, ion-exchanged water, etc., or may be treated with an ion-exchange resin to remove the influence of residual catalyst.

[0159] The proportion of the guanamine compound and the melamine compound in the entire curing agent is preferably 80% by mass or more, more preferably 85% by mass or more and 100% by mass or less, and even more preferably 90% by mass or more and 100% by mass or less.

[0160] The total content (solid content concentration in the coating solution) of the guanamine compound (preferably a compound represented by general formula (A)) and the melamine compound (preferably a compound represented by general formula (B)) is preferably 0.1% by mass or more and 5% by mass or less, and more preferably 1% by mass or more and 3% by mass or less. When the solid content concentration is 0.1% by mass or more, a dense film is easily formed, and strength and film-forming properties tend to be further improved. When the solid content concentration is 5% by mass or less, coating unevenness during film formation is suppressed, and film-forming properties are further improved.

[0161] The composition constituting the cured film that is the surface protective layer may further contain well-known additives such as a leveling agent (for example, a silicone-based leveling agent, etc.).

[0162] The formation of the surface protective layer is not particularly limited, and a known formation method can be used, but for example, the above-mentioned components are added to a solvent to form a coating film of a coating solution for forming the surface protective layer, the coating film is dried, and if necessary, a curing treatment such as heating is performed. In this case, if necessary, the leveling agent may be changed to increase the adhesive work, and the peeling of the surface protective layer from the charge transport layer may be further suppressed.

[0163] Examples of solvents for preparing a coating liquid for forming a surface protective layer 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, and alcohol solvents such as isopropyl alcohol and butanol. These solvents may be used alone or in combination of two or more. The coating liquid for forming the surface protective layer may be a solvent-free coating liquid.

[0164] Examples of a method for applying the coating liquid for forming a surface protective layer onto a photosensitive layer (e.g., a charge transport layer) include conventional methods such as dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, and curtain coating.

[0165] The thickness of the surface protective layer is set, for example, preferably in the range of 1 μm or more and 20 μm or less, and more preferably in the range of 2 μm or more and 10 μm or less.

[0166] [Conductive Substrate] Examples of conductive substrates include 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.). Examples of conductive substrates include paper, resin films, belts, etc. coated, vapor-deposited, or laminated with conductive compounds (e.g., conductive polymers, indium oxide, etc.), metals (e.g., aluminum, palladium, gold, etc.) or alloys. Here, "conductive" refers to a material having a volume resistivity of 1×10 13 This means that the resistance is less than Ωcm.

[0167] 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 to 0.5 μm in order to suppress interference fringes that occur when irradiating with laser light. When non-interfering light is used as the light source, roughening to prevent interference fringes is not particularly necessary, but it is suitable for extending the life of the conductive substrate since it suppresses the occurrence of defects due to unevenness on the surface.

[0168] Examples of surface roughening methods include wet honing, which is performed by spraying an abrasive suspended in water onto the conductive substrate, and continuous grinding by pressing the conductive substrate against a rotating grindstone. Examples of the processes include centerless grinding and anodizing.

[0169] As a method for roughening the surface, there can be mentioned a method in which, without roughening the surface of the conductive substrate, a 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 by the particles dispersed in the layer.

[0170] In the roughening treatment by anodization, an oxide film is formed on the surface of a conductive substrate made of metal (e.g., aluminum) by anodizing the substrate in an electrolyte solution using the substrate as the anode. Examples of electrolyte solutions include sulfuric acid solution and oxalic acid solution. However, the porous anodic oxide film formed by anodization is chemically active in its original state, easily contaminated, and has a large resistance variation depending on the environment. Therefore, it is preferable to perform a sealing treatment on the porous anodic oxide film, in which the micropores of the oxide film are filled by volume expansion caused by hydration reaction in pressurized steam or boiling water (metal salts such as nickel may be added) to change the film into a more stable hydrated oxide.

[0171] The thickness of the anodic oxide film is preferably, for example, from 0.3 μm to 15 μm. If the thickness is within this range, the film tends to exhibit a barrier property against injection and tends to suppress an increase in residual potential due to repeated use.

[0172] The conductive substrate may be subjected to a treatment with an acidic treatment solution or a boehmite treatment. Treatment with an acid treatment liquid is carried out, for example, as follows. First, an acid treatment liquid containing phosphoric acid, chromic acid, and hydrofluoric acid is prepared. The compounding ratios of phosphoric acid, chromic acid, and hydrofluoric acid in the acid treatment liquid are, for example, in the range of 10% by mass to 11% by mass for phosphoric acid, 3% by mass to 5% by mass for chromic acid, and 0.5% by mass to 2% by mass for hydrofluoric acid, and the total concentration of these acids is preferably in the range of 13.5% by mass to 18% by mass. The treatment temperature is preferably, for example, 42° C. to 48° C. The film thickness of the coating is preferably 0.3 μm to 15 μm.

[0173] The boehmite treatment is carried out, for example, by immersing the material in pure water at 90°C to 100°C for 5 to 60 minutes, or by contacting the material with heated steam at 90°C to 120°C for 5 to 60 minutes. The thickness of the coating is preferably 0.1 μm to 5 μm. This may be further anodized using an electrolyte solution having low coating solubility, such as adipic acid, boric acid, borates, phosphates, phthalates, maleates, benzoates, tartrates, or citrates.

[0174] [Sublayer] The undercoat layer is, for example, a layer containing inorganic particles and a binder resin.

[0175] For example, inorganic particles have a powder resistance (volume resistivity) of 1×10 2 Ωcm or more 1×10 11 Examples of such particles include inorganic particles with a particle size of Ωcm or less. Among these, examples of inorganic particles having the above-mentioned resistance value include metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, and zirconium oxide particles, and zinc oxide particles are particularly preferred.

[0176] The specific surface area of ​​inorganic particles by the BET method is, for example, 10 m 2 / g or higher is preferable. The volume average particle size of the inorganic particles is, for example, from 50 nm to 2000 nm (preferably from 60 nm to 1000 nm).

[0177] The content of the inorganic particles is, for example, preferably from 10% by mass to 80% by mass, more preferably from 40% by mass to 80% by mass, based on the binder resin.

[0178] The inorganic particles may be surface-treated. Two or more types of inorganic particles having different surface treatments or different particle sizes may be used in combination.

[0179] Examples of the surface treatment agent include a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, a surfactant, etc. In particular, a silane coupling agent is preferred, and a silane coupling agent having an amino group is more preferred.

[0180] Examples of silane coupling agents having an amino group include, but are not limited to, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, and N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane.

[0181] Silane coupling agents may be used in combination of two or more kinds. For example, a silane coupling agent having an amino group may be used in combination with another silane coupling agent. Examples of other silane coupling agents include, but are not limited to, vinyltrimethoxysilane, 3-methacryloxypropyl-tris(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.

[0182] The surface treatment method using the surface treatment agent may be any known method, and may be either a dry method or a wet method.

[0183] The amount of the surface treatment agent to be used is preferably, for example, 0.5% by mass or more and 10% by mass or less based on the inorganic particles.

[0184] Here, it is preferable that the undercoat layer contains an electron accepting compound (acceptor compound) together with the inorganic particles, from the viewpoints of improving the long-term stability of electrical properties and carrier blocking properties.

[0185] Examples of the electron-accepting compound include electron-transporting substances such as quinone compounds such as chloranil and bromoanil; tetracyanoquinodimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone; oxadiazole compounds such as 2-(4-biphenyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole, 2,5-bis(4-naphthyl)-1,3,4-oxadiazole and 2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole; xanthone compounds; thiophene compounds; diphenoquinone compounds such as 3,3',5,5'-tetra-t-butyldiphenoquinone; and benzophenone compounds. In particular, the electron-accepting compound is preferably a compound having an anthraquinone structure. Examples of the compound having an anthraquinone structure include hydroxyanthraquinone compounds, aminoanthraquinone compounds, and aminohydroxyanthraquinone compounds, and more specifically, anthraquinone, alizarin, quinizarin, anthrarufin, and purpurin.

[0186] The electron accepting compound may be contained in the undercoat layer in a dispersed state together with the inorganic particles, or may be contained in a state of being attached to the surfaces of the inorganic particles.

[0187] The method for attaching the electron accepting compound to the surface of the inorganic particles may be, for example, a dry method or a wet method.

[0188] The dry method is, for example, a method in which an electron-accepting compound is attached to the surface of inorganic particles by dropping an electron-accepting compound directly or dissolved in an organic solvent or spraying it together with dry air or nitrogen gas while stirring inorganic particles with a mixer or the like that exerts a large shearing force. The dropping or spraying of the electron-accepting compound is preferably performed at a temperature below the boiling point of the solvent. After dropping or spraying the electron-accepting compound, baking may be performed at 100° C. or higher. The temperature and time of baking are not particularly limited as long as electrophotographic properties can be obtained.

[0189] The wet method is a method in which, for example, an electron-accepting compound is added while dispersing inorganic particles in a solvent by stirring, ultrasonic waves, a sand mill, an attritor, a ball mill, etc., and the inorganic particles are stirred or dispersed, and then the solvent is removed to attach the electron-accepting compound to the surface of the inorganic particles. The solvent is removed, for example, by filtration or distillation. After the solvent is removed, baking may be performed at 100°C or higher. The baking temperature and time are not particularly limited as long as electrophotographic properties are obtained. In the wet method, moisture contained in the inorganic particles may be removed before adding the electron-accepting compound, and examples of such methods include a method of removing the moisture while stirring and heating in a solvent, and a method of removing the moisture by azeotropy with the solvent.

[0190] The attachment of the electron accepting compound may be carried out before or after the inorganic particles are subjected to a surface treatment with a surface treatment agent, or the attachment of the electron accepting compound and the surface treatment with the surface treatment agent may be carried out simultaneously.

[0191] The content of the electron accepting compound is, for example, from 0.01% by mass to 20% by mass, and preferably from 0.01% by mass to 10% by mass, based on the inorganic particles.

[0192] Examples of the binder resin used in the undercoat layer include known materials such as acetal resins (e.g., polyvinyl butyral, etc.), 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-alkyd resins, urea resins, phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, alkyd resins, and epoxy resins; zirconium chelate compounds; titanium chelate compounds; aluminum chelate compounds; titanium alkoxide compounds; organic titanium compounds; and silane coupling agents. Examples of the binder resin used in the undercoat layer include charge transporting resins having charge transporting groups, conductive resins (such as polyaniline, etc.), and the like.

[0193] Among these, the binder resin used in the undercoat layer is preferably a resin that is insoluble in the coating solvent of the upper layer, and in particular, a resin obtained by reacting at least one resin selected from the group consisting of thermosetting resins such as urea resins, phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, unsaturated polyester resins, alkyd resins, and epoxy resins, with a curing agent is preferred. When two or more of these binder resins are used in combination, the mixing ratio is set as necessary.

[0194] The undercoat layer may contain various additives for improving electrical properties, environmental stability, and image quality. Examples of the additives include known materials such as polycyclic condensation and azo-based electron transport pigments, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, silane coupling agents, etc. As described above, silane coupling agents are used for surface treatment of inorganic particles, and may also be added to the undercoat layer as an additive.

[0195] Examples of silane coupling agents as additives include vinyltrimethoxysilane, 3-methacryloxypropyl-tris(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, 3-chloropropyltrimethoxysilane, and the like.

[0196] Examples of the zirconium chelate compound include zirconium butoxide, zirconium ethyl acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate zirconium butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octanoate, zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, and isostearate zirconium butoxide.

[0197] Examples of titanium chelate compounds include tetraisopropyl titanate, tetra-n-butyl titanate, butyl titanate dimer, tetra(2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt, titanium lactate, titanium lactate ethyl ester, titanium triethanolamine, and polyhydroxytitanium stearate.

[0198] Examples of aluminum chelate compounds include aluminum isopropylate, monobutoxyaluminum diisopropylate, aluminum butyrate, diethylacetoacetate aluminum diisopropylate, and aluminum tris(ethylacetoacetate).

[0199] These additives may be used alone or as a mixture or polycondensation product of a plurality of compounds.

[0200] The undercoat layer preferably has a Vickers hardness of 35 or more. The surface roughness (ten-point average roughness) of the undercoat layer is preferably adjusted to between 1 / (4n) (n is the refractive index of the upper layer) and 1 / 2 of the wavelength λ of the exposure laser used in order to suppress moire images. Resin particles or the like may be added to the undercoat layer to adjust the surface roughness. Examples of the resin particles include silicone resin particles and crosslinked polymethyl methacrylate resin particles. The surface of the undercoat layer may be polished to adjust the surface roughness. Examples of the polishing method include buffing, sandblasting, wet honing, grinding, and the like.

[0201] The formation of the undercoat layer is not particularly limited, and a known formation method can be used. For example, the undercoat layer can be formed by forming a coating film of a coating solution for forming the undercoat layer in which the above-mentioned components are added to a solvent, drying the coating film, and heating it as necessary.

[0202] Examples of the solvent for preparing the coating liquid for forming the undercoat layer include known organic solvents, such as alcohol-based solvents, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, ketone-based solvents, ketone alcohol-based solvents, ether-based solvents, and ester-based solvents. Specific examples of these solvents include ordinary organic solvents such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene.

[0203] Examples of the method for dispersing the inorganic particles when preparing the coating liquid for forming the undercoat layer include known methods such as those using a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker.

[0204] Examples of the method for applying the coating liquid for forming the undercoat layer onto the conductive substrate include ordinary methods such as blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0205] The average thickness of the undercoat layer is preferably from 10 μm to 50 μm, and more preferably from 15 μm to 40 μm.

[0206] [Middle class] An intermediate layer may further be provided between the undercoat layer and the photosensitive layer. The intermediate layer is, for example, a layer containing a resin. Examples of the resin used in the intermediate layer include polymer compounds such as acetal resins (e.g., polyvinyl butyral, etc.), 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-alkyd resins, phenol-formaldehyde resins, and melamine resins. The intermediate layer may be a layer containing an organometallic compound. Examples of the organometallic compound used in the intermediate layer include organometallic compounds containing metal atoms such as zirconium, titanium, aluminum, manganese, and silicon. The compounds used in the intermediate layer may be used alone or as a mixture or polycondensation product of a plurality of compounds.

[0207] Among these, the intermediate layer is preferably a layer containing an organometallic compound containing zirconium atoms or silicon atoms.

[0208] The formation of the intermediate layer is not particularly limited, and a known formation method can be used. For example, the intermediate layer can be formed by forming a coating film of a coating solution for forming an intermediate layer in which the above components are added to a solvent, drying the coating film, and heating it as necessary. The intermediate layer can be formed by any of the usual coating methods, such as dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating and curtain coating.

[0209] The average thickness of the intermediate layer is preferably from 0.1 μm to 3 μm. The intermediate layer may be used as an undercoat layer.

[0210] [Charge Generation Layer] The charge generation layer is, for example, a layer containing a charge generation material and a binder resin. The charge generation layer may also be a vapor deposition layer of the charge generation material. The vapor deposition layer of the charge generation material is suitable for use with a non-coherent light source such as an LED (Light Emitting Diode) or an organic EL (Electro-Luminescence) image array.

[0211] Examples of the charge generating material include azo pigments such as bisazo and trisazo; condensed aromatic pigments such as dibromoanthanthrone; perylene pigments; pyrrolopyrrole pigments; phthalocyanine pigments; zinc oxide; and trigonal selenium.

[0212] Among these, in order to accommodate laser exposure in the near infrared region, it is preferable to use a metal phthalocyanine pigment or a metal-free phthalocyanine pigment as the charge generating material, specifically, for example, hydroxygallium phthalocyanine, chlorogallium phthalocyanine, dichlorotin phthalocyanine, or titanyl phthalocyanine.

[0213] On the other hand, in order to accommodate laser exposure in the near ultraviolet region, preferred charge generating materials include condensed aromatic pigments such as dibromoanthanthrone, thioindigo pigments, porphyrazine compounds, zinc oxide, trigonal selenium, and bisazo pigments.

[0214] The above charge generating material may be used when using an incoherent light source such as an LED or an organic EL image array that emits light at a central wavelength of 450 nm or more and 780 nm or less, but from the viewpoint of resolution, when using a photosensitive layer that is a thin film of 20 μm or less, the electric field strength in the photosensitive layer becomes high, and a decrease in charging due to charge injection from the substrate, that is, an image defect called a black spot, is likely to occur. This becomes noticeable when a charge generating material that is a p-type semiconductor that is likely to generate dark current, such as trigonal selenium or a phthalocyanine pigment, is used.

[0215] In contrast, when n-type semiconductors such as fused aromatic pigments, perylene pigments, and azo pigments are used as charge generating materials, dark current is unlikely to occur, and image defects called black spots can be suppressed even in thin films. The n-type is determined by the polarity of the flowing photocurrent using the commonly used time-of-flight method, and those that are more likely to pass electrons as carriers than holes are considered to be n-type.

[0216] The binder resin used in the charge generating layer may be selected from a wide range of insulating resins, and may also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, polysilane, and the like. Examples of binder resins include polyvinyl butyral resins, polyarylate resins (polycondensates of bisphenols and aromatic dicarboxylic acids, etc.), polycarbonate resins, polyester resins, phenoxy resins, vinyl chloride-vinyl acetate copolymers, polyamide resins, acrylic resins, polyacrylamide resins, polyvinylpyridine resins, cellulose resins, urethane resins, epoxy resins, casein, polyvinyl alcohol resins, polyvinylpyrrolidone resins, etc. Here, "insulating" refers to a material having a volume resistivity of 1×10 13 This means that the resistance is Ωcm or more. These binder resins may be used alone or in combination of two or more.

[0217] The compounding ratio of the charge generating material to the binder resin is preferably within a range of 10:1 to 1:10 by mass.

[0218] The charge generating layer may contain other known additives.

[0219] The formation of the charge generating layer is not particularly limited, and a known formation method can be used. For example, the above-mentioned components are added to a solvent to form a coating film of a coating solution for forming the charge generating layer, the coating film is dried, and if necessary, The charge generating layer may be formed by vapor deposition of the charge generating material. The vapor deposition of the charge generating layer is particularly suitable when a fused aromatic pigment or a perylene pigment is used as the charge generating material.

[0220] Examples of the solvent for preparing the coating liquid for forming the charge generating layer 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, methylene chloride, chloroform, chlorobenzene, toluene, etc. These solvents may be used alone or in combination of two or more.

[0221] Examples of methods for dispersing particles (e.g., charge generating material) in the coating liquid for forming a charge generating layer include media dispersers such as ball mills, vibration ball mills, attritors, sand mills, and horizontal sand mills, and medialess dispersers such as stirrers, ultrasonic dispersers, roll mills, and high-pressure homogenizers. Examples of high-pressure homogenizers include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision under high pressure, and a penetration method in which the dispersion liquid is dispersed by penetrating a fine flow path under high pressure. During this dispersion, it is effective to adjust the average particle size of the charge generating material in the coating liquid for forming the charge generating layer to 0.5 μm or less, preferably 0.3 μm or less, and more preferably 0.15 μm or less.

[0222] Examples of a method for applying the coating liquid for forming the charge generating layer onto the undercoat layer (or onto the intermediate layer) include conventional methods such as blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0223] The average thickness of the charge generating layer is preferably from 0.1 μm to 5.0 μm, and more preferably from 0.2 μm to 2.0 μm.

[0224] [Charge transport layer] The charge transport layer is, for example, a layer containing a charge transport material and a binder resin, and may be a layer containing a polymer charge transport material.

[0225] Examples of the charge transport material include electron transporting compounds such as quinone compounds such as p-benzoquinone, chloranil, bromanil, and anthraquinone; tetracyanoquinodimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone; xanthone compounds; benzophenone compounds; cyanovinyl compounds; and ethylene compounds. Examples of the charge transport material include hole transporting compounds such as triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, and hydrazone compounds. These charge transport materials may be used alone or in combination, but are not limited to these.

[0226] 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 preferable.

[0227] [ka]

[0228] In 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 -CH-CH=CH-CH=C(R T7 )(R T8 ) is shown. T4 , R T5 , R T6 , R T7 , and R T8 each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Examples of the substituent for each of the above groups include a halogen atom, an alkyl group having from 1 to 5 carbon atoms, and an alkoxy group having from 1 to 5 carbon atoms. Examples of the substituent for each of the above groups also include a substituted amino group substituted with an alkyl group having from 1 to 3 carbon atoms.

[0229] [ka]

[0230] In structural formula (a-2), R T91 and R T92 R 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 from 1 to 5 carbon atoms, an alkoxy group having from 1 to 5 carbon atoms, an amino group substituted with an alkyl group having from 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 ) and 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. Examples of the substituent for each of the above groups include a halogen atom, an alkyl group having from 1 to 5 carbon atoms, and an alkoxy group having from 1 to 5 carbon atoms. Examples of the substituent for each of the above groups also include a substituted amino group substituted with an alkyl group having from 1 to 3 carbon atoms.

[0231] Among the triarylamine derivatives represented by the structural formula (a-1) and the benzidine derivatives represented by the structural formula (a-2), in particular, "-C6H4-CH=CH-CH=C(R T7)(R T8 )" and triarylamine derivatives having "-CH=CH-CH=C(R T15 )(R T16 ) is preferred from the viewpoint of charge mobility.

[0232] As the polymer charge transport material, known materials having charge transport properties such as poly-N-vinylcarbazole and polysilane are used. In particular, polyester polymer charge transport materials are particularly preferred. The polymer charge transport material may be used alone or in combination with a binder resin.

[0233] Examples of the binder resin used in the charge transport layer 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 alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinylcarbazole, polysilane, etc. Among these, polycarbonate resin or polyarylate resin is suitable as the binder resin. These binder resins are used alone or in combination of two or more. The compounding ratio of the charge transport material to the binder resin is preferably from 10:1 to 1:5 by mass.

[0234] The charge transport layer may contain other well-known additives.

[0235] The formation of the charge transport layer is not particularly limited, and a known formation method can be used. For example, the charge transport layer can be formed by forming a coating film of a coating liquid for forming the charge transport layer in which the above components are added to a solvent, drying the coating film, and heating it as necessary.

[0236] Examples of solvents for preparing the coating liquid for forming the charge transport layer include ordinary organic solvents such as aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene, ketones such as acetone and 2-butanone, halogenated aliphatic hydrocarbons such as methylene chloride, chloroform, and ethylene chloride, and cyclic or linear ethers such as tetrahydrofuran and ethyl ether. These solvents may be used alone or in combination of two or more.

[0237] Examples of a coating method for coating the coating liquid for forming the charge transport layer on the charge generating layer include ordinary methods such as blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating and curtain coating.

[0238] <Image forming apparatus, process cartridge> The image forming apparatus according to the present embodiment includes the electrophotographic photosensitive member according to the present embodiment, a charging device which charges the surface of the electrophotographic photosensitive member, an electrostatic latent image forming device which forms an electrostatic latent image on the surface of the charged electrophotographic photosensitive member, a developing device which develops the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image, and a transfer device which transfers the toner image onto the surface of a recording medium.

[0239] The image forming apparatus according to the present embodiment may be any of known image forming apparatuses, such as an apparatus provided with a fixing device that fixes a toner image transferred onto the surface of a recording medium; an apparatus of a direct transfer type that directly transfers a toner image formed on the surface of an electrophotographic photosensitive member onto a recording medium; an apparatus of an intermediate transfer type that performs primary transfer of a toner image formed on the surface of an electrophotographic photosensitive member onto the surface of an intermediate transfer member and secondary transfer of the toner image transferred onto the surface of the intermediate transfer member onto the surface of a recording medium; an apparatus provided with a cleaning device that cleans the surface of an electrophotographic photosensitive member before charging after the transfer of a toner image; an apparatus provided with a static elimination device that irradiates the surface of an electrophotographic photosensitive member with static elimination light to eliminate static electricity before charging after the transfer of a toner image; and an apparatus provided with an electrophotographic photosensitive member heating member for increasing the temperature of the electrophotographic photosensitive member and reducing the relative temperature.

[0240] In the case of an intermediate transfer type device, the transfer device is configured to have, for example, an intermediate transfer body onto whose surface a toner image is transferred, a primary transfer device which primarily transfers the toner image formed on the surface of an electrophotographic photosensitive body onto the surface of the intermediate transfer body, and a secondary transfer device which secondarily transfers the toner image transferred onto the surface of the intermediate transfer body onto the surface of a recording medium.

[0241] It is preferable that the transfer device comprises an intermediate transfer belt, a blade that contacts the outer peripheral surface of the intermediate transfer belt and cleans the outer peripheral surface, a primary transfer device having a primary transfer member that primarily transfers a toner image formed on the surface of an image carrier to the outer peripheral surface of the intermediate transfer belt, and a secondary transfer device that is arranged in contact with the outer peripheral surface of the intermediate transfer belt and has a secondary transfer member that secondarily transfers the toner image transferred to the outer peripheral surface of the intermediate transfer belt to the surface of a recording medium. The transfer pressure during the primary transfer is preferably a linear pressure of 17 g / cm or less, more preferably a linear pressure of 15 g / cm or less, and even more preferably a linear pressure of 10 g / cm or more and 12 g / cm or less. When the transfer pressure in the primary transfer is a linear pressure of 17 g / cm or less, the load applied to the interface between the charge transport layer and the surface protective layer during transfer from the electrophotographic photosensitive member is kept small, and peeling of the surface protective layer from the charge transport layer due to reaction to the load is further suppressed. When the transfer pressure in the primary transfer is a linear pressure of 10 g / cm or more, image defects due to poor transfer during transfer from the electrophotographic photosensitive member are reduced.

[0242] The image forming apparatus according to the present embodiment may be either a dry development type image forming apparatus or a wet development type image forming apparatus (a development type using a liquid developer).

[0243] In the image forming apparatus according to the present embodiment, for example, a portion including an electrophotographic photosensitive member may have a cartridge structure (process cartridge) that is detachably attached to the image forming apparatus. As the process cartridge, for example, a process cartridge including the electrophotographic photosensitive member according to the present embodiment is preferably used. The process cartridge may include, in addition to the electrophotographic photosensitive member, at least one selected from the group consisting of a charging device, an electrostatic latent image forming device, a developing device, and a transfer device.

[0244] An example of an image forming apparatus according to the present embodiment will be described below, but the present invention is not limited to this. Principal parts shown in the drawings will be described, and descriptions of other parts will be omitted.

[0245] FIG. 2 is a schematic diagram showing an example of the image forming apparatus according to the present embodiment. As shown in FIG. 2, the image forming apparatus 100 according to the present embodiment includes a process cartridge 300 including an electrophotographic photoreceptor 7, an exposure device 9 (an example of an electrostatic latent image forming device), 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 disposed at a position where it can expose the electrophotographic photoreceptor 7 from the opening of the process cartridge 300, the transfer device 40 is disposed at a position facing the electrophotographic photoreceptor 7 via the intermediate transfer body 50, and the intermediate transfer body 50 is disposed with a part of it in contact with the electrophotographic photoreceptor 7. Although not shown, the image forming apparatus 100 also includes a secondary transfer device that transfers 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 device.

[0246] 2 supports an electrophotographic photoreceptor 7, a charging device 8 (an example of a charging device), a developing device 11 (an example of a developing device), and a cleaning device 13 (an example of a cleaning device) integrally within a housing. The cleaning device 13 has a cleaning blade (an example of a cleaning member) 131, which is disposed so as to come into contact with the surface of the electrophotographic photoreceptor 7. The cleaning member may not be in the form of the cleaning blade 131, but may be a conductive or insulating fibrous member, which may be used alone or in combination with the cleaning blade 131.

[0247] FIG. 2 shows an example of an image forming apparatus equipped with a fibrous member 132 (roll-shaped) that supplies lubricant 14 to the surface of electrophotographic photosensitive member 7, and a fibrous member 133 (flat brush-shaped) that assists in cleaning, which are arranged as needed.

[0248] Hereinafter, each configuration of the image forming apparatus according to this embodiment will be described.

[0249] -Charging device- As the charging device 8, for example, a contact type charger using a conductive or semiconductive charging roller, charging brush, charging film, charging rubber blade, charging tube, etc. Also, a non-contact type roller charger, a scorotron charger or corotron charger that utilizes corona discharge, or other chargers known per se, can be used.

[0250] -Exposure equipment- The exposure device 9 may be, for example, an optical device that exposes the surface of the electrophotographic photoreceptor 7 with light such as semiconductor laser light, LED light, or liquid crystal shutter light in a predetermined image. The wavelength of the light source is within the spectral sensitivity range of the electrophotographic photoreceptor. The wavelength of the semiconductor laser is mainly near infrared light having an oscillation wavelength of about 780 nm. However, it is not limited to this wavelength, and a laser having an oscillation wavelength of 600 nm or a blue laser having an oscillation wavelength of 400 nm to 450 nm may also be used. In addition, a surface-emitting laser light source capable of outputting multiple beams is also effective for forming a color image.

[0251] -Developing device- The developing device 11 may be, for example, a general developing device that develops by contacting or non-contacting a developer. The developing device 11 is not particularly limited as long as it has the above-mentioned functions, and may be selected according to the purpose. For example, it may be a known developing device that has a function of attaching a one-component developer or a two-component developer to the electrophotographic photoreceptor 7 using a brush, roller, or the like. Among them, it is preferable to use a developing roller that holds a developer on its surface.

[0252] The developer used in the developing device 11 may be a one-component developer containing only toner, or may be a two-component developer containing toner and a carrier. The developer may be magnetic or non-magnetic. Known developers are used.

[0253] -Cleaning device- The cleaning device 13 is a cleaning blade type device equipped with a cleaning blade 131. In addition to the cleaning blade type, a fur brush cleaning type or a simultaneous development and cleaning type may also be adopted.

[0254] -Transfer device- Examples of the transfer device 40 include known transfer chargers such as a contact type transfer charger using a belt, roller, film, rubber blade, etc., and a scorotron transfer charger or corotron transfer charger that utilizes corona discharge.

[0255] -Intermediate transfer body- A belt-like intermediate transfer belt containing semiconductive polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber, etc. is used as the intermediate transfer body 50. The intermediate transfer body may be in the form of a drum other than a belt.

[0256] FIG. 3 is a schematic diagram showing another example of the image forming apparatus according to the present embodiment. 3 is a tandem-type multi-color image forming apparatus 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 photosensitive body is used for each color. The image forming apparatus 120 has the same configuration as the image forming apparatus 100, except that it is a tandem type. EXAMPLES

[0257] Hereinafter, the embodiments of the present invention will be described in detail with reference to examples, but the embodiments of the present invention are in no way limited to these examples. In the following description, unless otherwise specified, "parts" and "%" are by mass. In the following description, syntheses, treatments, manufactures, etc. were carried out at room temperature (25° C.±3° C.) unless otherwise specified.

[0258] [Synthesis of resin XA] 20 parts by mass of xylene was added to a 200 ml three-neck flask and heated and stirred at 110° C. Next, a mixture of a monomer having a unit represented by formula (X1), a monomer having a unit represented by formula (X2), and a monomer having a unit represented by formula (X3) of the types and amounts shown in Table 1, 10 parts by mass of butyl acetate, and 1 part by mass of the polymerization catalyst t-butylperoxy-2-ethylhexanoate was slowly added dropwise at 110° C. over 2 hours under a nitrogen atmosphere. After that, the mixture was reacted at 120° C. for 2 hours to copolymerize, and a resin was obtained.

[0259] [Synthesis of resin XB] A resin was obtained under the same specifications as in the synthesis of Resin XA, except that the dropping temperature was changed to 120°C.

[0260] [Synthesis of resin XC] A resin was obtained under the same specifications as in the synthesis of Resin XA, except that the dropping temperature was changed to 90°C.

[0261] [Synthesis of resin XD] A resin was obtained under the same specifications as in the synthesis of Resin XA, except that the types and amounts of a monomer having a unit represented by formula (X1), a monomer having a unit represented by formula (X2), and a monomer having a unit represented by formula (X3) were shown in Table 1, and the dropping temperature was changed to 100°C.

[0262] [Synthesis of resin XE] A resin was obtained under the same specifications as in the synthesis of Resin XA, except that the types and amounts of a monomer having a unit represented by formula (X1), a monomer having a unit represented by formula (X2), and a monomer having a unit represented by formula (X3) were shown in Table 1, and the dropping temperature was changed to 80°C.

[0263] [Synthesis of resin XF] A resin was obtained under the same specifications as in the synthesis of Resin XA, except that the types and amounts of a monomer having a unit represented by formula (X1), a monomer having a unit represented by formula (X2), and a monomer having a unit represented by formula (X3) were shown in Table 1, and the dropping temperature was changed to 110°C.

[0264] [Synthesis of Resin XG] A resin was obtained under the same specifications as in the synthesis of Resin XA, except that the types and amounts of a monomer having a unit represented by formula (X1), a monomer having a unit represented by formula (X2), and a monomer having a unit represented by formula (X3) were shown in Table 1, and the dropping temperature was changed to 105°C.

[0265] [Synthesis of resin XH] A resin was obtained under the same specifications as in the synthesis of Resin XA, except that the types and amounts of a monomer having a unit represented by formula (X1), a monomer having a unit represented by formula (X2), and a monomer having a unit represented by formula (X3) were shown in Table 1, the dropping temperature was changed to 80°C, and the reaction time was changed to 3 hours.

[0266] [Synthesis of Resin XI] A resin was obtained under the same specifications as in the synthesis of Resin XA, except that the types and amounts of a monomer having a unit represented by formula (X1), a monomer having a unit represented by formula (X2), and a monomer having a unit represented by formula (X3) were shown in Table 1, the dropwise addition temperature was changed to 75°C, and the reaction time was changed to 3.5 hours.

[0267] [Synthesis of resin XJ] The monomer having a unit represented by formula (X1), the monomer having a unit represented by formula (X2) and the monomer having a unit represented by formula (X3) were used in the amounts and types shown in Table 1. The dropwise addition temperature was set at 80°C. A resin was obtained under the same specifications as in the synthesis of Resin XA, except that the temperature was changed to 0° C. and the reaction time was changed to 4 hours.

[0268] [Synthesis of resin XK] A resin was obtained under the same specifications as in the synthesis of Resin XA, except that the types and amounts of a monomer having a unit represented by formula (X1), a monomer having a unit represented by formula (X2), and a monomer having a unit represented by formula (X3) were shown in Table 1, and the dropwise addition temperature was changed to 135°C.

[0269] [Synthesis of Resin XL] A resin was obtained under the same specifications as in the synthesis of Resin XA, except that the types and amounts of the monomer having a unit represented by Formula (X1), the monomer having a unit represented by Formula (X2), and the monomer having a unit represented by Formula (X3) were shown in Table 1.

[0270] [Synthesis of resin XM] A resin was obtained under the same specifications as in the synthesis of Resin XA, except that the types and amounts of the monomer having a unit represented by Formula (X1), the monomer having a unit represented by Formula (X2), and the monomer having a unit represented by Formula (X3) were shown in Table 1.

[0271] [Synthesis of resin XN] A resin was obtained under the same specifications as in the synthesis of Resin XA, except that the types and amounts of the monomer having a unit represented by Formula (X1), the monomer having a unit represented by Formula (X2), and the monomer having a unit represented by Formula (X3) were shown in Table 1.

[0272] The weight average molecular weight Mw of each resin determined by the above-mentioned measurement method is shown in Table 1. In Table 1, "-" next to each material item indicates that the material is not included.

[0273] [Table 1]

[0274] <Preparation of Electrophotographic Photoreceptor> [Example 1] As a conductive substrate, an aluminum cylindrical tube having an outer diameter of 30 mm, a length of 250 mm, and a wall thickness of 1 mm was prepared.

[0275] - Formation of undercoat layer - Zinc oxide (average particle size 70 nm, specific surface area 15 m 2 100 parts of a silane coupling agent (trade name: KBM603, manufactured by Shin-Etsu Chemical Co., Ltd., N-2-(aminoethyl)-3-aminopropyltrimethoxysilane) was added to the mixture and stirred for 2 hours. The toluene was then distilled off under reduced pressure, and the mixture was baked at 120°C for 3 hours to obtain zinc oxide surface-treated with the silane coupling agent.

[0276] 110 parts of the surface-treated zinc oxide was mixed with 500 parts of tetrahydrofuran by stirring, and a solution of 0.6 parts of alizarin dissolved in 50 parts of tetrahydrofuran was added thereto, followed by stirring for 5 hours at 50° C. Thereafter, the solid content was filtered off by reduced pressure filtration and dried under reduced pressure at 60° C. to obtain zinc oxide with alizarin added thereto.

[0277] 100 parts of a solution of 60 parts of alizarin-added zinc oxide, 13.5 parts of a curing agent (blocked isocyanate, product name: Sumidur 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.), and 15 parts of butyral resin (product name: S-LEC BM-1, manufactured by Sekisui Chemical Co., Ltd.) dissolved in 68 parts of methyl ethyl ketone was mixed with 5 parts of methyl ethyl ketone, and dispersed for 2 hours in a sand mill using glass beads of 1 mm diameter to obtain a dispersion. 0.005 parts of dioctyltin dilaurate as a catalyst and 4 parts of silicone resin particles (product name: Tospearl 145, manufactured by Momentive Performance Materials Co., Ltd.) were added to the dispersion to obtain a coating liquid for forming an undercoat layer. The coating liquid for forming an undercoat layer was applied to the outer peripheral surface of a conductive substrate by a dip coating method, and dried and cured at 170°C for 40 minutes to form an undercoat layer. The average thickness of the undercoat layer was 25 μm.

[0278] - Formation of charge generation layer - A mixture of 15 parts of hydroxygallium phthalocyanine (having diffraction peaks at Bragg angles (2θ±0.2°) of at least 7.5°, 9.9°, 12.5°, 16.3°, 18.6°, 25.1°, and 28.3° in the X-ray diffraction spectrum using Cukα characteristic X-rays) as a charge generating material, 10 parts of vinyl chloride-vinyl acetate copolymer resin (trade name: VMCH, manufactured by Nippon Unicar Co., Ltd.) as a binder resin, and 200 parts of n-butyl acetate was dispersed in a sand mill using glass beads with a diameter of 1 mm for 4 hours. 175 parts of n-butyl acetate and 180 parts of methyl ethyl ketone were added to the dispersion and stirred to obtain a coating solution for forming a charge generating layer. The coating solution for forming a charge generating layer was dip-coated on the undercoat layer and dried at room temperature (25°C±3°C) to form a charge generating layer with an average thickness of 0.18 μm.

[0279] - Formation of charge transport layer - 55 parts of polycarbonate Z resin with a viscosity average molecular weight of 50,000 and 40 parts of charge transport material CTM-1 were dissolved in 270 parts of tetrahydrofuran and 30 parts of toluene to obtain a coating solution for forming a charge transport layer. The coating solution for forming a charge transport layer was dip-coated on the charge generation layer at a coating speed corresponding to the target film thickness, and dried at 115°C for 50 minutes to form a charge transport layer. The average film thickness of the charge transport layer was the thickness shown in Table 2.

[0280] [ka]

[0281] - Formation of a surface protection layer - To a mixed solvent of 30 parts by mass of isopropanol and 15 parts by mass of n-butanol, 10 parts by mass of the charge transport material (I-25), 10 parts by mass of (I-8), 2 parts by mass of (I-26), 1 part by mass of (I-27), and 0.5 parts by mass of methoxymethylated melamine ((B)-2) were added. The mixture was dissolved by stirring for 2 hours at 50° C. Next, after cooling to room temperature (25° C.), 0.1 part by mass of a curing catalyst Nacure 5925 (manufactured by King Industry Co., Ltd.) and 0.08 part by mass of the resin X-A were added to obtain a coating liquid for forming a surface protective layer. The coating solution for forming the surface protective layer was dip-coated on the charge transport layer at a coating speed corresponding to the target film thickness, dried to the touch for 10 minutes at 25° C., and then dried and cured for 40 minutes at 150° C. to obtain the photoreceptor of Example 1. The average film thickness of the surface protective layer was the thickness shown in Table 2.

[0282] [Examples 2 to 7, Examples 9 to 23, and Comparative Examples 1 to 4] The thickness of the surface protective layer, the thickness of the charge transport layer, and the thickness T of the charge transport layer CT (μm) and the thickness of the surface protective layer T OVC (μm) ratio (T CT / T OVC )(In the table, “ratio (T CT / T OVC Photoreceptors of each example were produced under the same specifications as in Example 1, except that the specifications shown in Table 2 were used for the powder (denoted as "powder") and the powder (denoted as "powder") ...

[0283] [Example 11] In the later-described [Evaluation of Peelability], the specifications were the same as those of Example 2, except that the linear pressure in the primary transfer was within the range shown in Table 2.

[0284] [Reference example 1] A photoreceptor was produced with the same specifications as in Example 1, except that in the step of forming the surface protective layer, a resin of the type and mass ratio shown in Table 2 was used instead of the resin (X).

[0285] In each table, "mass percentage of resin (mass%)" refers to the mass percentage of the resin (X) in the surface protective layer. In comparative examples in which KP-340 or KP-104 was used instead of resin (X), KP-340 or KP-104 was regarded as resin (X) to calculate the "mass percentage of resin (mass%)."

[0286] <Evaluation> [Evaluation of streak-like image defects] Image forming device Color 1000i Press (manufactured by Fujifilm Business Innovation Co., Ltd.) With each photoreceptor attached, 50,000 chart images with an image density (area coverage) of 10% were printed continuously on A4-size plain paper in an environment of 30°C temperature and 85% relative humidity (high temperature and high humidity), and the 10th image and the 50,000th image were visually observed, and streak-like image defects were classified into the following categories A to E. The fewer streak-like image defects there were, the more the coating defects in the surface protective layer were reduced. A: There are no streak-like image defects and no problems with image quality. B: A slight streak-like image defect is present in a portion of the image, but is not a problem in practical use. C: A clear streak-like image defect is present in a portion of the image, but is not a problem in practical use. D: Half of the image has streak-like image defects that cannot be ignored in terms of image quality. E: There are streak defects throughout the entire image, which is problematic for practical use.

[0287] [Evaluation of peelability] The photoreceptor of each example was attached to an image forming apparatus Color 1000i Press (manufactured by Fujifilm Business Innovation Co., Ltd.) equipped with an intermediate transfer belt as the first transfer body. The linear pressure of the primary transfer was set to the range shown in Table 2, and the linear pressure of the secondary transfer was set to 120 g / cm. At a process speed of 260 mm / sec, 50,000 chart images with an image density (area coverage) of 10% were continuously output on A4 size plain paper. Thereafter, the electrophotographic photoreceptor was removed from the image forming apparatus, and the surface protective layer was observed under a microscope, and the peeling of the surface protective layer from the charge transport layer was evaluated using the following evaluation. A: No peeling of the surface protection layer from the charge transport layer in the entire area B: 1 to 5 peelings C: Peeling of 6 to 10 D: Peeling of 10 or more but less than 20 E: More than 20 peelings

[0288] [Evaluation of image output] A DocuCentre VC2263 (manufactured by Fujifilm Business Innovation Co., Ltd.) was prepared as an image forming apparatus containing an electrostatic image developer, and the electrophotographic photoreceptor of each example was attached to it, and 500 sheets of halftone images (image density 30%) were output on A4 size plain paper, and the image on the 500th sheet was evaluated. The evaluation criteria are shown below. A: No problem with halftone images B: Halftone images have dots of different sizes (not a problem) C: The dots in the halftone image are not resolved.

[0289] [Table 2]

[0290] As shown in the above table, it was found that the photoreceptors of the examples were more inhibited in peeling off the surface protective layer from the charge transport layer than the photoreceptors of the comparative examples.

[0291] The present embodiment includes the following aspects. (((1))) A conductive substrate; a charge generating layer provided on the conductive substrate; a charge transport layer disposed on the charge generating layer; a surface protective layer provided on the charge transport layer; having The charge transport layer has a thickness of 8 μm or more and 25 μm or less, The surface protective layer has a thickness of 10 μm or less, and is a cured film of a composition including a resin (X) having at least one of a unit represented by the following formula (X1) and a unit represented by the following formula (X2), and a reactive group-containing charge transport material having a reactive group and a charge transport skeleton in the same molecule: Electrophotographic photoreceptor. [ka] In formula (X1), R 101 , R 102 and R 103 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; L 101 represents a single bond, an alkylene group having from 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof; L 102 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof; R 104 and R 105 are each independently an alkyl group having 1 to 5 carbon atoms, n is an integer of 0 to 300, R 106 , R 107 and R 108 are each independently an alkyl group having 1 to 5 carbon atoms, or -O-[Si(R 109 )(R 110 )O] m -Si(R 111 )(R 112 )(R 113 ) and R 109 , R 110 , R 111 , R 112 and R 113each independently represents an alkyl group having 1 to 5 carbon atoms, and m is an integer of 0 to 20. In formula (X2), R 201 , R 202 and R 203 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; L 201 represents a single bond, an alkylene group having from 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof; L 202 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof; R 204 is an alkyl group having 6 to 30 carbon atoms. (((2))) The thickness T of the charge transport layer CT (μm) and the thickness T of the surface protective layer OVC (μm) ratio (T CT / T OVC ) is 1.42 or more and 25 or less. (((3))) The electrophotographic photoreceptor according to (((1))) above, wherein the charge transport layer has a thickness of 8 μm or more and 20 μm or less. (((4))) The electrophotographic photoreceptor according to (((3))) above, wherein the charge transport layer has a thickness of 9 μm or more and 20 μm or less. (((5))) The electrophotographic photoreceptor according to (((1))) above, wherein the surface protective layer has a thickness of 1 μm or more and 10 μm or less. (((6))) The electrophotographic photoreceptor according to (((5))) above, wherein the surface protective layer has a thickness of 5 μm or more and 9 μm or less. (((7))) An electrophotographic photoreceptor according to any one of (((1))) to (((6))), A process cartridge that is detachably attached to an image forming apparatus. (((8))) The electrophotographic photoreceptor according to any one of (((1))) to (((6))) above; a charging device for charging a surface of the electrophotographic photoreceptor; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the electrophotographic photoreceptor; The electrostatic latent image formed on the surface of the electrophotographic photoreceptor is developed with a developer containing a toner. a developing device for forming a toner image by using the toner; a transfer device for transferring the toner image onto a surface of a recording medium; An image forming apparatus comprising: (((9))) The transfer device is An intermediate transfer belt; a blade that comes into contact with an outer peripheral surface of the intermediate transfer belt and cleans the outer peripheral surface; a primary transfer device having a primary transfer member for primarily transferring a toner image formed on a surface of an image carrier onto an outer peripheral surface of the intermediate transfer belt at a linear pressure of 17 g / cm or less; a secondary transfer device that is disposed in contact with an outer peripheral surface of the intermediate transfer belt and has a secondary transfer member that secondarily transfers the toner image transferred onto the outer peripheral surface of the intermediate transfer belt onto a surface of a recording medium; The image forming apparatus according to any one of (((8))) above,

[0292] According to the invention related to (((1))), there is provided an electrophotographic photoreceptor in which peeling of the surface protective layer from the charge transport layer is suppressed, as compared with a case in which the thickness of the charge transport layer exceeds 25 μm, or the thickness of the surface protective layer exceeds 10 μm. According to the invention related to (((2)), the thickness T CT (μm) and the thickness T of the surface protective layer OVC (μm) ratio (T CT / T OVC ) exceeds 25, peeling of the surface protective layer from the charge transport layer is suppressed. According to the invention related to (((3))), an electrophotographic photoreceptor is provided in which peeling of the surface protective layer from the charge transport layer is suppressed, as compared with the case where the charge transport layer has a thickness of less than 8 μm or more than 20 μm. According to the invention related to (((4))), an electrophotographic photoreceptor is provided in which peeling of the surface protective layer from the charge transport layer is suppressed, as compared with the case where the charge transport layer has a thickness of less than 9 μm or more than 20 μm. According to the invention related to (((5))), an electrophotographic photoreceptor is provided in which peeling of the surface protective layer from the charge transport layer is suppressed, as compared with the case where the thickness of the surface protective layer is less than 1 μm or exceeds 10 μm. According to the invention related to (((6))), an electrophotographic photoreceptor is provided in which peeling of the surface protective layer from the charge transport layer is suppressed, as compared with the case where the thickness of the surface protective layer is less than 5 μm or exceeds 9 μm.

[0293] According to the invention related to (((7))) or (((8))), there is provided a process cartridge or an image forming apparatus equipped with an electrophotographic photoreceptor in which peeling of the surface protective layer from the charge transport layer is suppressed compared to when an electrophotographic photoreceptor is equipped with an electrophotographic photoreceptor in which the thickness of the charge transport layer exceeds 25 μm, or when an electrophotographic photoreceptor is equipped with an electrophotographic photoreceptor in which the thickness of the surface protective layer exceeds 10 μm. According to the invention related to (((9))), The present invention provides an image forming apparatus having an electrophotographic photosensitive member in which peeling of a surface protective layer from a charge transport layer is suppressed compared to a case in which the transfer device includes an intermediate transfer belt, a blade that comes into contact with the outer peripheral surface of the intermediate transfer belt and cleans the outer peripheral surface, a primary transfer device having a primary transfer member that primarily transfers a toner image formed on the surface of an image carrier to the outer peripheral surface of the intermediate transfer belt at a transfer pressure of more than 17 g / cm, and a secondary transfer device having a secondary transfer member that is arranged in contact with the outer peripheral surface of the intermediate transfer belt and secondarily transfers the toner image transferred to the outer peripheral surface of the intermediate transfer belt to the surface of a recording medium. [Explanation of symbols]

[0294] 1 Conductive substrate, 2 Undercoat layer, 3 Charge generation layer, 4 Charge transport layer, 5 Photosensitive layer, 10A photoreceptor, 10B photoreceptor

[0295] 7 electrophotographic photosensitive member, 8 charging device, 9 exposure device, 11 developing device, 13 cleaning device, 14 lubricant, 40 transfer device, 50 intermediate transfer body, 100 image forming apparatus, 120 image forming apparatus, 131 cleaning blade, 132 fibrous member (roll-shaped), 133 fibrous member (flat brush-shaped), 300 process cartridge

Claims

1. A conductive substrate; a charge generating layer provided on the conductive substrate; a charge transport layer disposed on the charge generating layer; a surface protective layer provided on the charge transport layer; having The charge transport layer has a thickness of 8 μm or more and 25 μm or less, The surface protective layer has a thickness of 10 μm or less, and is a cured film of a composition including: a resin (X) having at least one of a unit represented by the following formula (X1) and a unit represented by the following formula (X2); and a reactive group-containing charge transport material having a reactive group and a charge transport skeleton in the same molecule: Electrophotographic photoreceptor. 【Chemistry 1】 In formula (X1), R １０１ , R １０２ and R １０３ each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; L １０１ represents a single bond, an alkylene group having from 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof; L １０２ represents a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof; R １０４ and R １０５ are each independently an alkyl group having 1 to 5 carbon atoms, n is an integer of 0 to 300, R １０６ , R １０７ and R １０８ are each independently an alkyl group having 1 to 5 carbon atoms, or -O-[Si(R １０９ )(R １１０ )O] ｍ -Si(R １１１ )(R １１２ )(R １１３ ) and R １０９ , R １１０ , R １１１ , R １１２ and R １１３ each independently represents an alkyl group having 1 to 5 carbon atoms, and m represents an integer of 0 to 20. In formula (X2), R ２０１ , R ２０２ and R ２０３ each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; L ２０１ represents a single bond, an alkylene group having from 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof; L ２０２ represents a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof; R ２０４ is an alkyl group having 6 to 30 carbon atoms.

2. The thickness T of the charge transport layer ＣＴ (μm) and the thickness T of the surface protective layer ＯＶＣ (μm) (T ＣＴ / T ＯＶＣ 2. The electrophotographic photoreceptor according to claim 1, wherein the value of n is 1.42 or more and 25 or less.

3. 2. The electrophotographic photoreceptor according to claim 1, wherein the charge transport layer has a thickness of 8 [mu]m or more and 20 [mu]m or less.

4. 4. The electrophotographic photoreceptor according to claim 3, wherein the charge transport layer has a thickness of 9 [mu]m or more and 20 [mu]m or less.

5. 2. The electrophotographic photoreceptor according to claim 1, wherein the surface protective layer has a thickness of 1 [mu]m or more and 10 [mu]m or less.

6. 6. The electrophotographic photoreceptor according to claim 5, wherein the surface protective layer has a thickness of 5 [mu]m or more and 9 [mu]m or less.

7. The electrophotographic photoreceptor according to any one of claims 1 to 6 is provided, A process cartridge that is detachably attached to an image forming apparatus.

8. The electrophotographic photoreceptor according to any one of claims 1 to 6, a charging device for charging a surface of the electrophotographic photoreceptor; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the electrophotographic photoreceptor; a developing device for developing an electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image; a transfer device for transferring the toner image onto a surface of a recording medium; An image forming apparatus comprising:

9. The transfer device is An intermediate transfer belt; a blade that comes into contact with an outer peripheral surface of the intermediate transfer belt and cleans the outer peripheral surface; a primary transfer device having a primary transfer member for primarily transferring a toner image formed on a surface of an image carrier onto an outer peripheral surface of the intermediate transfer belt at a linear pressure of 17 g / cm or less; a secondary transfer device that is disposed in contact with an outer peripheral surface of the intermediate transfer belt and has a secondary transfer member that secondarily transfers the toner image transferred onto the outer peripheral surface of the intermediate transfer belt onto a surface of a recording medium; The image forming apparatus according to claim 8 .

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