Electrophotographic photoreceptor, process cartridge, and image forming apparatus

Abstract

The invention provides an electrophotographic photoreceptor, a process cartridge, and an image forming apparatus. The electrophotographic photoreceptor includes: a conductive substrate; a charge generation layer provided on the conductive substrate; the charge transmission layer is arranged on the charge generation layer; and a surface protection layer provided on the charge transport layer, the charge transport layer having a film thickness of 8 [mu] m or more and 25 [mu] m or less. The surface protection layer is a cured film of a composition having a film thickness of 10 [mu] m or less and containing a resin (X) having a unit represented by formula (X1) and / or a unit represented by formula (X2), and a reactive group-containing charge transport material having a reactive group and a charge transport skeleton in the same molecule. [Chemical Formula 1] # imgabs0 #

Description

Technical Field

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

[0002] Patent document 1 discloses "an image forming device that generates an electrostatic latent image on a photosensitive body by exposing the surface of the photosensitive body charged by a charging unit, and after developing the generated electrostatic latent image to form a toner image, transfers the toner image on the photosensitive body to a transferee, and cleans the transferred photosensitive body surface by a cleaning unit. The image forming device is characterized in that the charging unit is made based on a contact charging method with the surface of the photosensitive body, the photosensitive body is provided with a protective layer having a harderness than the photosensitive layer on the photosensitive layer, and the cleaning unit is a metal cleaning scraper whose front end abuts against the surface of the photosensitive body."

[0003] Patent Document 2 discloses “a composition for forming an overcoat layer of an organic photoreceptor, characterized by comprising a polyamino ether and a solvent”.

[0004] Patent Document 3 discloses “a coating composition for forming an outer coating layer of an organic photoreceptor, characterized by comprising a polyamino ether, an electron transporting substance, and an alcohol solvent”.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-161668

[0006] Patent Document 2: Japanese Patent Application Publication No. 2004-139022

[0007] Patent Document 3: Japanese Patent Application Publication No. 2004-133470 Summary of the invention

[0008] In a conventional electrophotographic photoreceptor having a laminated photosensitive layer and a surface protective layer, the surface protective layer may be peeled off from the charge transport layer.

[0009] The present invention aims to provide an electrophotographic photoreceptor in which the peeling of the surface protective layer from the charge transport layer is suppressed compared with a case where the film thickness of the charge transport layer exceeds 25 μm or a case where the film thickness of the surface protective layer exceeds 10 μm.

[0010] Specific means for solving the above-mentioned problems include the following aspects.

[0011] <1> An electrophotographic photoreceptor comprising:

[0012] Conductive substrate;

[0013] A charge generating layer is disposed on the conductive substrate;

[0014] a charge transport layer disposed on the charge generation layer; and

[0015] A surface protection layer is disposed on the charge transport layer,

[0016] The charge transport layer has a thickness of 8 μm or more and 25 μm or less.

[0017] The surface protective layer is a cured film having a film thickness of 10 μm or less and comprising a composition of 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.

[0018] [Chemical formula 1]

[0019] Formula (X1)

[0020] Formula (X2)

[0021] 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 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof, 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, and 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 ), 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.

[0022] In formula (X2), R201 , R 202 and R 203 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, L 201 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof, 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, and R 204 It is an alkyl group having 6 to 30 carbon atoms.

[0023] <2> The electrophotographic photoreceptor according to <1>, wherein

[0024] The film thickness T of the charge transport layer CT (μm) and the film thickness T of the surface protection layer OVC (μm) ratio (T CT / T OVC ) is greater than 1.42 and less than 25.

[0025] <3> The electrophotographic photoreceptor according to <1>, wherein

[0026] The charge transport layer has a film thickness of 8 μm or more and 20 μm or less.

[0027] <4> The electrophotographic photoreceptor according to <3>, wherein

[0028] The charge transport layer has a film thickness of 9 μm or more and 20 μm or less.

[0029] <5> The electrophotographic photoreceptor according to <1>, wherein

[0030] The surface protection layer has a film thickness of 1 μm or more and 10 μm or less.

[0031] <6> The electrophotographic photoreceptor according to <5>, wherein

[0032] The surface protection layer has a film thickness of 5 μm or more and 9 μm or less.

[0033] <7> A process cartridge comprising the electrophotographic photoreceptor according to any one of <1> to <6>, wherein:

[0034] The process cartridge is attachable to and detachable from the image forming apparatus.

[0035] <8> An image forming apparatus comprising:

[0036] The electrophotographic photoreceptor according to any one of <1> to <6>;

[0037] A charging device for charging the surface of the electrophotographic photoreceptor;

[0038] An electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the electrophotographic photoreceptor;

[0039] a developing device for developing the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image; and

[0040] The transfer device transfers the toner image to the surface of a recording medium.

[0041] <9> The image forming apparatus according to <8>, wherein:

[0042] The transfer device comprises:

[0043] Intermediate transfer belt;

[0044] a scraper contacting with the outer peripheral surface of the intermediate transfer belt and cleaning the outer peripheral surface;

[0045] a primary transfer device having a primary transfer member for primary transferring a toner image formed on a surface of an image holding member to an outer peripheral surface of the intermediate transfer belt at a transfer pressure of 17 g / cm or less; and

[0046] The secondary transfer device includes a secondary transfer member arranged in contact with the outer peripheral surface of the intermediate transfer belt and secondarily transferring the toner image transferred to the outer peripheral surface of the intermediate transfer belt to a surface of a recording medium.

[0047] Effects of the Invention

[0048] According to the invention of <1>, there is provided an electrophotographic photoreceptor in which separation of the surface protective layer from the charge transport layer is suppressed compared with a case where the film thickness of the charge transport layer exceeds 25 μm or a case where the film thickness of the surface protective layer exceeds 10 μm.

[0049] According to the invention described in <2>, there is provided a CT (μm) and the film thickness T of the surface protection layer OVC (μm) ratio (T CT / T OVC ) exceeds 25, the electrophotographic photoreceptor in which the peeling of the surface protective layer from the charge transport layer is suppressed.

[0050] According to the invention as set forth in <3>, there is provided an electrophotographic photoreceptor in which separation of the surface protective layer from the charge transport layer is suppressed compared with a case where the film thickness of the charge transport layer is less than 8 μm or exceeds 20 μm.

[0051] According to the invention as set forth in <4>, there is provided an electrophotographic photoreceptor in which separation of the surface protective layer from the charge transport layer is suppressed compared with a case where the film thickness of the charge transport layer is less than 9 μm or exceeds 20 μm.

[0052] According to the invention as set forth in <5>, there is provided an electrophotographic photoreceptor in which separation of the surface protective layer from the charge transport layer is suppressed compared with a case where the film thickness of the surface protective layer is less than 1 μm or exceeds 10 μm.

[0053] According to the invention as set forth in <6>, there is provided an electrophotographic photoreceptor in which separation of the surface protective layer from the charge transport layer is suppressed compared with a case where the film thickness of the surface protective layer is less than 5 μm or exceeds 9 μm.

[0054] According to the invention described in <7> or <8>, there is provided a processing box or an image forming device comprising an electrophotographic photosensitive body, wherein peeling of the surface protective layer from the charge transport layer is suppressed compared to a case where the thickness of the charge transport layer exceeds 25 μm or a case where the thickness of the surface protective layer exceeds 10 μm.

[0055] According to the invention involved in <9>, there is provided an image forming device comprising an electronic photographic photosensitive body, i.e., an electronic photographic photosensitive body in which peeling of a surface protective layer from a charge transport layer is suppressed compared to a case in which a transfer device comprises an intermediate transfer belt, a scraper which contacts with the outer peripheral surface of the intermediate transfer belt and cleans the outer peripheral surface, a primary transfer device having a primary transfer component which transfers a toner image formed on the surface of an image retaining body to the outer peripheral surface of the intermediate transfer belt at a transfer pressure exceeding 17 g / cm by a linear pressure, and a secondary transfer device having a secondary transfer component which is arranged in contact with the outer peripheral surface of the intermediate transfer belt and transfers the toner image transferred to the outer peripheral surface of the intermediate transfer belt to the surface of a recording medium by a secondary transfer component. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Embodiments of the present invention will be described in detail with reference to the following drawings.

[0057] Picture 1 is a partial cross-sectional view showing an example of a layer structure of an electrophotographic photoreceptor according to the first embodiment;

[0058] Picture 2 is a schematic structural diagram showing an example of an image forming apparatus according to the present embodiment;

[0059] Picture 3It is a schematic configuration diagram showing another example of the image forming apparatus according to the present embodiment.

[0060] Explanation of symbols

[0061] 1-conductive substrate, 2-undercoat layer, 3-charge generating layer, 4-charge transporting layer, 5-photosensitive layer, 10A-photoreceptor, 10B-photoreceptor, 7-electrophotographic photoreceptor, 8-charging device, 9-exposure device, 11-developing device, 13-cleaning device, 14-lubricant, 40-transfer device, 50-intermediate transfer body, 100-image forming device, 120-image forming device, 131-cleaning blade, 132-fibrous component (roller-shaped), 133-fibrous component (flat brush-shaped), 300-processing box. DETAILED DESCRIPTION

[0062] Hereinafter, embodiments of the present invention will be described. These descriptions and examples are intended to illustrate the embodiments and do not limit the scope of the embodiments.

[0063] In the present invention, a numerical range expressed using "to" indicates a range including the numerical values ​​before and after "to" as the minimum value and the maximum value, respectively.

[0064] In the numerical ranges recorded in stages in the present invention, the upper limit or lower limit recorded in one numerical range may also be replaced by the upper limit or lower limit of the numerical range recorded in other stages. In addition, in the numerical ranges recorded in the present invention, the upper limit or lower limit of the numerical range may also be replaced by the value shown in the embodiment.

[0065] In the present invention, the word "process" is included in this term if the purpose of the process can be achieved not only in an independent process but also in a case where the process cannot be clearly distinguished from other processes.

[0066] In the present invention, when the embodiments are described with reference to the drawings, the structure of the embodiments is not limited to the structure shown in the drawings. In addition, the sizes of the components in the drawings are conceptual, and the relative relationship between the sizes of the components is not limited thereto.

[0067] In the present invention, each component may also include a plurality of corresponding substances. In the present invention, when referring to the amount of each component in the composition, when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified, it indicates the total amount of the plurality of substances present in the composition.

[0068] In the present invention, multiple types of particles corresponding to each component may be contained. When multiple types of particles corresponding to each component are present in the composition, unless otherwise specified, the particle size of each component represents a value for a mixture of the multiple types of particles present in the composition.

[0069] In the present invention, unless otherwise specified, an alkyl group and an alkylene group include linear, branched, and cyclic groups.

[0070] In the present invention, regarding the organic group, aromatic ring, linking group, alkyl group, alkylene group, aryl group, aralkyl group, alkoxy group, aryloxy group and the like, the hydrogen atom in the group may be substituted by a halogen atom.

[0071] In the present invention, a polymer having no siloxane skeleton in the main chain and having a siloxane skeleton in a branch (ie, a graft chain) is referred to as a "graft-type polysiloxane compound".

[0072] In the present invention, a polymer having no siloxane skeleton in the main chain and having a long-chain alkyl group in a branch (ie, a graft chain) is referred to as a "graft-type long-chain alkyl-based resin."

[0073] In the present invention, a polymer having a siloxane skeleton in its main chain is referred to as a "linear polysiloxane compound".

[0074] <Electronic Photographic Photoreceptor>

[0075] The electronic photographic photosensitive body involved in this embodiment has a conductive substrate, a charge generating layer arranged on the conductive substrate, a charge transport layer arranged on the charge generating layer, and a surface protection layer arranged on the charge transport layer, wherein the charge transport layer has a film thickness of not less than 8 μm and not more than 25 μm, and the surface protection layer is a cured film of a composition having a film thickness of not more than 10 μm and comprising 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 charge transport material containing a reactive group having a reactive group and a charge transport skeleton in the same molecule.

[0076] [Chemical formula 2]

[0077] Formula (X1)

[0078] Formula (X2)

[0079] 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 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof, 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, and 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 ), 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.

[0080] 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 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof, 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, and R 204 It is an alkyl group having 6 to 30 carbon atoms.

[0081] In the past, it is known that in an electrophotographic photoreceptor, in order to increase the life of the photoreceptor that is reduced by wear (the so-called wear life) or maintain the stability of image quality, a cured film of a composition, i.e., a surface protective layer, is provided on the photosensitive layer. However, in the process of forming the surface protective layer, the existing photoreceptor having a cured film of a composition, i.e., a surface protective layer, is prone to coating defects such as excessive water, bubbles, or uneven coating in the coating. Therefore, in the area where the coating defect occurs, streaky image defects are likely to occur.

[0082] As a result of in-depth research by the present inventors, it was found that in a photoreceptor having the surface protective layer, by setting the specification to include resin (X) in the cured film, the coating defects of the surface protective layer can be suppressed. Specifically, the resin (X) is a grafted polysiloxane compound or a grafted long-chain alkyl resin, so compared with existing straight-chain polysiloxane compounds, it is easy to ensure appropriate wettability when forming the surface protective layer, and the film-forming property is excellent. In addition, during the curing accompanied by volume shrinkage when the coating is dried, the unevenness of the coating is also suppressed. As a result, it is believed that the streaky image defects caused by coating defects are suppressed.

[0083] However, in an electrophotographic photosensitive body having a surface protective layer containing a resin (X) in a cured film, when transferring from the electrophotographic photosensitive body, a load applied to the interface between the charge transport layer and the surface protective layer may cause the surface protective layer to peel off from the charge transport layer due to the reaction to the load.

[0084] In contrast, the inventors of the present invention conducted further in-depth studies and found that by setting the film thickness of the surface protection layer and the charge transport layer to the above-mentioned thickness, i.e., a thinner film thickness than before, even when transferring from the electronic photographic photosensitive body, the load applied to the interface between the charge transport layer and the surface protection layer is reduced, thereby suppressing the peeling of the surface protection layer from the charge transport layer.

[0085] In the present invention, “peeling of the surface protection layer from the charge transport layer” also includes the concept of floating or defect of the surface protection layer from the charge transport layer.

[0086] Picture 1 This is a partial cross-sectional view schematically showing an example of the layer structure of the photoreceptor according to the present embodiment. Picture 1 The photoreceptor 10A shown has a laminated photosensitive layer. The photoreceptor 10A has a structure in which an undercoat layer 2, a charge generating layer 3, and a charge transporting layer 4 are sequentially laminated on a conductive substrate 1, and the charge generating layer 3 and the charge transporting layer 4 constitute a photosensitive layer 5 (a so-called functionally separated photosensitive layer). The photoreceptor 10A may have an intermediate layer (not shown) between the undercoat layer 2 and the charge generating layer 3.

[0087] Hereinafter, each layer of the photoreceptor will be described in detail. Note that reference numerals are omitted.

[0088] The film thickness of the charge transport layer is 8 μm or more and 25 μm or less, for example, preferably 8 μm or more and 20 μm or less, and more preferably 9 μm or more and 20 μm or less.

[0089] If the film thickness of the charge transport layer is 8 μm or more, the loads applied to the charge transport layer and the surface protection layer are not balanced, and the load applied to the interface between the charge transport layer and the surface protection layer is reduced, resulting in a reaction, thereby further suppressing the peeling of the surface protection layer from the charge transport layer. In addition, it is easy to ensure the charge transport performance. In addition, if it is less than 8 μm, it is sometimes difficult to maintain the charge.

[0090] When the film thickness of the charge transport layer is 25 μm or less, the reaction to 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.

[0091] The method for adjusting the film thickness of the charge transport layer to fall within the above range is not particularly limited, and examples thereof include a method of adjusting the coating speed in the charge transport layer-forming coating liquid.

[0092] The film thickness of the charge transport layer was determined as follows.

[0093] The surface protective layer was peeled off from the electrophotographic photoreceptor, and the film thickness of the exposed charge transport layer was measured at 10 points from the outer peripheral surface side using a dielectric film thickness measuring device (Fischer Instruments, FISCHERSCOPE MMS). The arithmetic average of the values ​​was defined as the film thickness of the charge transport layer.

[0094] The film thickness of the surface protection layer is 10 μm or less, for example, preferably 1 μm or more and 10 μm or less, and more preferably 5 μm or more and 9 μm or less.

[0095] When the thickness of the surface protective layer is larger than 10 μm, the residual charge of the photoreceptor may increase, and image formation may become difficult. Therefore, the thickness of the surface protective layer is preferably 10 μm or less, for example.

[0096] If the thickness of the surface protection layer is 1 μm or more, the loads applied to the charge transport layer and the surface protection layer are unbalanced, and the load applied to the interface between the charge transport layer and the surface protection layer is reduced, thereby further suppressing the peeling of the surface protection layer from the charge transport layer. In addition, the life of the photoreceptor that is reduced by wear (the so-called wear life) or the image quality stability is improved.

[0097] The method for setting the film thickness of the surface protective layer to fall within the above range is not particularly limited, and examples thereof include a method of adjusting the coating speed in the coating liquid for forming a surface protective layer.

[0098] The film thickness of the surface protection layer was determined as follows.

[0099] 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 by a dielectric film thickness measuring device (Fischer Instruments, FISCHERSCOPE MMS). The arithmetic mean of each value is set as the film thickness of the surface protective layer. When measuring the film thickness of the surface protective layer, the sample coated with only the protective layer is used for measurement.

[0100] In the electrophotographic photoreceptor according to the present embodiment, the film thickness T of the charge transport layer is CT (μm) and the film thickness T of the surface protection layer OVC (μm) ratio (T CT / T OVC ) is preferably, for example, 1.42 or more and 25 or less, and more preferably 1.42 or more and 1.85 or less.

[0101] If compared with (T CT / T OVC ) is less than 1.42, the thickness of the surface protective layer is too thin relative to the thickness of the charge transport layer, so that the loads applied to the charge transport layer and the surface protective layer respectively will not be balanced, thereby reducing the reaction in the load applied to the interface between the charge transport layer and the surface protective layer, thereby further suppressing the peeling of the surface protective layer from the charge transport layer.

[0102] If compared with (T CT / T OVC ) is greater than 25, the thickness of the surface protective layer is too thick relative to the thickness of the charge transport layer, so that the loads applied to the charge transport layer and the surface protective layer respectively will not be balanced, thereby reducing the load applied to the interface between the charge transport layer and the surface protective layer, thereby further suppressing the peeling of the surface protective layer from the charge transport layer.

[0103] 〔Surface protection layer〕

[0104] The surface protection layer is a layer having a film thickness of 10 μm or less and composed of a cured film of a composition comprising a resin (X) having at least one of a unit represented by the following formula (X1) and a unit represented by the formula (X2) and a charge transport material containing a reactive group having a reactive group and a charge transport skeleton in the same molecule (i.e., a layer comprising a polymer or a crosslinked body of the charge transport material containing a reactive group). The composition may further contain other materials such as a curing agent and a leveling agent as needed.

[0105] [Resin (X)]

[0106] The resin (X) has at least one of the unit (X1) and the unit (X2). The resin (X) may contain other structural units in addition to the unit (X1) and the unit (X2).

[0107] The resin (X) has at least one of the units (X1) and (X2) to become a graft polymer having a siloxane chain or a long-chain alkyl group in the side chain, and when the surface protective layer is formed, it is easy to ensure appropriate wettability and excellent film-forming properties. In addition, during the curing process accompanied by volume shrinkage when the coating film is dried, unevenness of the coating film is also suppressed. As a result, streaky image defects caused by coating film defects are suppressed.

[0108] The unit (X1) is a structural unit represented by the following formula (X1).

[0109] [Chemical formula 3]

[0110] Formula (X1)

[0111] 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 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof, 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, and 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 ), 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.

[0112] R 101 , R 102 and R 103The alkyl group having 1 to 5 carbon atoms may be any of linear, branched, and cyclic. The alkyl group preferably has 1 to 4 carbon atoms, more preferably 1 to 3 carbon atoms, further preferably 1 or 2, and particularly preferably 1 carbon atom.

[0113] R 101 and R 102 For example, each independently is preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0114] R 103 For example, a hydrogen atom or a methyl group is preferred.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] Examples of the cyclic alkylene group having 3 to 5 carbon atoms include cyclopropylene, cyclobutylene, and cyclopentylene.

[0119] L 101 The aromatic ring which may have a substituent may be 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 a benzene ring and a naphthalene ring are preferred.

[0120] The hydrogen atom of the aromatic ring may be substituted by an alkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a halogen atom, etc. As the substituent when the aromatic ring is substituted, for example, an alkyl group having 1 to 5 carbon atoms is preferred, an alkyl group having 1 to 3 carbon atoms is more preferred, and a methyl group is further preferred.

[0121] L 101 For example, -C(=O)O- or an aromatic ring which may have a substituent is preferred, -C(=O)O- or a benzene ring which may have a substituent is more preferred, and -C(=O)O- or a benzene ring is further preferred.

[0122] L 102For example, preferably, it is a single bond, a straight-chain alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof, and more preferably, it is a straight-chain alkylene group having 2 to 4 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof.

[0123] R 104 and R 105 The alkyl group having 1 to 5 carbon atoms may be any of linear, branched, and cyclic. The alkyl group preferably has 1 to 4 carbon atoms, more preferably 1 to 3 carbon atoms, further preferably 1 or 2, and particularly preferably 1 carbon atom.

[0124] R 104 and R 105 For example, each independently 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 still more preferably a methyl group.

[0125] n is an integer of 0 to 300, for example, preferably an integer of 1 to 250, more preferably an integer of 3 to 200, and further preferably an integer of 5 to 150.

[0126] 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 any of linear, branched, and cyclic. The alkyl group preferably has 1 to 4 carbon atoms, more preferably 1 to 3 carbon atoms, further preferably 1 or 2, and particularly preferably 1 carbon atom.

[0127] When R 106 , R 107 and R 108 When each independently represents an alkyl group having 1 to 5 carbon atoms, for example, 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.

[0128] R 109 , R 110 , R 111 , R 112 and R 113 For example, each independently 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 still more preferably a methyl group.

[0129] m is an integer of 0 to 20, for example, preferably an integer of 0 to 15, more preferably an integer of 0 to 10, and further preferably an integer of 0 to 5.

[0130] 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).

[0131] [Chemical formula 4]

[0132] Formula (X1-1)

[0133] Formula (X1-2)

[0134] In formula (X1-1) and formula (X1-2), R 103 is a hydrogen atom or a methyl group, 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 ), 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.

[0135] 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 respectively the same as 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 meaning and are used in the same way.

[0136] L in formula (X1-1) 102 For example, 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- is preferred; 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- is more preferred; and 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- is further preferred.

[0137] Formation L 102 The number of atoms of "O" in -C(=O)O- and "Si" in -(Si(CH3)2O)n- in the shortest linking formula (X1-1) is, for example, preferably greater than 1 and less than 5, more preferably greater than 2 and less than 4, and further preferably 3 or 4.

[0138] L in formula (X1-2) 102 For example, preferably, it is a straight-chain alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof; more preferably, it is a straight-chain alkylene group having 1 to 4 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof; further preferably, it is a straight-chain alkylene group having 1 to 3 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof.

[0139] Formation L 102 The number of atoms of the benzene ring and the "Si" in -(Si(CH3)2O)n- in the shortest connecting formula (X1-2) is, for example, preferably greater than 1 and less than 7, more preferably greater than 1 and less than 6, and further preferably greater than 1 and less than 5.

[0140] Specific examples of the unit (X1-1) are shown below, but the unit (X1-1) is not limited thereto. Me is a methyl group, and n-Bu is a n-butyl group.

[0141] [Chemical formula 5]

[0142] <![CDATA[R 103 ]]> <![CDATA[L 102 ]]> n <![CDATA[R 106 ]]> <![CDATA[R 107 ]]> <![CDATA[R 108 ]]> X1-1-1 H <![CDATA[-(CH2)2-]]> 5 Me Me Me X1-1-2 Me <![CDATA[-(CH2)2-O-(CH2)3-]]> 35 Me Me Me ×1-1-3 Me <![CDATA[-(CH2)2-O-(CH2)3-]]> 61 Me Me Me X1-1-4 Me <![CDATA[-(CH2)3-]]> 1 Me Me Me X1-1-5 Me <![CDATA[-(CH2)3-]]> 2 Me Me Me X1-1-6 Me <![CDATA[-(CH2)3-]]> 3 Me Me Me X1-1-7 Me <![CDATA[-(CH2)3-]]> 4 Me Me Me X1-1-8 Me <![CDATA[-(CH2)3-]]> 5 Me Me Me X1-1-9 Me <![CDATA[-(CH2)3-]]> 6 Me Me Me X1-1-10 Me <![CDATA[-(CH2)3-]]> 7 Me Me Me X1-1-11 Me <![CDATA[-(CH2)3-]]> 8 Me Me Me X1-1-12 Me <![CDATA[-(CH2)3-]]> 9 Me Me Me X1-1-13 Me <![CDATA[-(CH2)3-]]> 10 Me Me Me X1-1-14 Me <![CDATA[-(CH2)3-]]> 28 Me Me Me X1-1-15 Me <![CDATA[-(CH2)3-]]> 29 Me Me Me X1-1-16 Me <![CDATA[-(CH2)3-]]> 59 Me Me Me X1-1-17 Me <![CDATA[-(CH2)3-]]> 60 Me Me Me X1-1-18 Me <![CDATA[-(CH2)3-]]> 65 Me Me Me X1-1-19 Me <![CDATA[-(CH2)3-]]> 132 Me Me Me X1-1-20 Me <![CDATA[-(CH2)3-]]> 159 Me Me Me X1-1-21 Me <![CDATA[-(CH2)3-]]> 160 Me Me Me X1-1-22 Me <![CDATA[-(CH2)3-]]> 267 Me Me Me X1-1-23 Me <![CDATA[-(CH2)3-]]> 10 n-Bu Me Me X1-1-24 Me <![CDATA[-(CH2)3-]]> 11 n-Bu Me Me X1-1-25 Me <![CDATA[-(CH2)3-]]> 64 n-Bu Me Me X1-1-26 Me <![CDATA[-(CH2)3-]]> 65 n-Bu Me Me X1-1-27 Me <![CDATA[-(CH2)3-]]> 131 n-Bu Me Me X1-1-28 Me <![CDATA[-(CH2)3-]]> 132 n-Bu Me Me X1-1-29 Me <![CDATA[-(CH2)3-]]> 0 <![CDATA[-O-SiMe3]]> <![CDATA[-O-SiMe3]]> <![CDATA[-O-SiMe3]]>

[0143] [Chemical formula 6]

[0144]

[0145] Specific examples of the unit (X1-2) are shown below, but the unit (X1-2) is not limited thereto. Me is a methyl group, and n-Bu is a n-butyl group.

[0146] [Chemical formula 7]

[0147] <![CDATA[R 103 ]]> <![CDATA[L 102 ]]> n <![CDATA[R 106 ]]> <![CDATA[R 107 ]]> <![CDATA[R 108 ]]> X1-2-1 H -O- 0 Me Me Me X1-2-2 H -O- 1 Me Me Me X1-2-3 H -O- 2 Me Me Me X1-2-4 H -O- 3 Me Me Me X1-2-5 H -O- 4 Me Me Me X1-2-6 H -O- 8 Me Me Me X1-2-7 H -O- 10 Me Me Me X1-2-8 H -O- 20 Me Me Me X1-2-9 H <![CDATA[-(C=O)O-(CH2)2-O-(CH2)3-]]> 35 Me Me Me X1-2-10 H <![CDATA[-(C=O)O-(CH2)2-O-(CH2)3-]]> 61 Me Me Me X1-2-11 H <![CDATA[-O(C=O)-(CH2)2-]]> 18 Me Me Me X1-2-12 H <![CDATA[-CH2-O(C=O)-(CH2)2-]]> 18 Me Me Me X1-2-13 H <![CDATA[-(C=O)O-(CH2)2-O-(CH2)3-]]> 11 n-Bu Me Me X1-2-14 H <![CDATA[-(C=O)O-(CH2)2-O-(CH2)3-]]> 65 n-Bu Me Me X1-2-15 H <![CDATA[-(C=O)O-(CH2)2-O-(CH2)3-]]> 132 n-Bu Me Me X1-2-16 H <![CDATA[-(C=O)O-(CH2)3-]]> 0 <![CDATA[-O-SiMe3]]> <![CDATA[-O-SiMe3]]> Me

[0148] 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.

[0149] [Chemical formula 8]

[0150] <![CDATA[R 101 ]]> <![CDATA[R 102 ]]> <![CDATA[R 103 ]]> <![CDATA[L 101 ]]> <![CDATA[L 102 ]]> n <![CDATA[R 104 ]]> <![CDATA[R 105 ]]> <![CDATA[R 106 ]]> <![CDATA[R 107 ]]> <![CDATA[R 108 ]]> X1-E-1 H H H Single key Single key 72 Me Me Me Me Me X1-E-2 H H H Single key Single key 86 Me Me Me Me Me X1-E-3 H H H Single key Single key 0 - - Me Me Me X1-E-4 H H H Single key Single key 0 - - Et Et Et X1-E-5 H H H Single key Single key 0 - - <![CDATA[-O-SiMe3]]> <![CDATA[-O-SiMe3]]> <![CDATA[-O-SiMe3]]> X1-E-6 H H H Single key Single key 1 Me Me Me Me Me X1-E-7 H H H Single key Single key 0 - - Me Me Ph

[0151] The unit (X2) is a structural unit represented by the following formula (X2).

[0152] [Chemical formula 9]

[0153] Formula (X2)

[0154] 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 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof, 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, and R 204 It is an alkyl group having 6 to 30 carbon atoms.

[0155] R 201 , R 202 and R 203 The alkyl group having 1 to 5 carbon atoms may be any of linear, branched, and cyclic. The alkyl group preferably has 1 to 4 carbon atoms, more preferably 1 to 3 carbon atoms, further preferably 1 or 2, and particularly preferably 1 carbon atom.

[0156] R 201 and R 202 Each independently represents, for example, a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0157] R 203 For example, a hydrogen atom or a methyl group is preferred.

[0158] 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.

[0159] 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.

[0160] 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.

[0161] Examples of the cyclic alkylene group having 3 to 5 carbon atoms include cyclopropylene, cyclobutylene, and cyclopentylene.

[0162] L 201 The aromatic ring which may have a substituent may be 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 a benzene ring and a naphthalene ring are preferred.

[0163] The hydrogen atom of the aromatic ring may be substituted by an alkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a halogen atom, etc. As the substituent when the aromatic ring is substituted, for example, an alkyl group having 1 to 5 carbon atoms is preferred, an alkyl group having 1 to 3 carbon atoms is more preferred, and a methyl group is further preferred.

[0164] L 201 For example, -C(=O)O- or an aromatic ring which may have a substituent is preferred, -C(=O)O- or a benzene ring which may have a substituent is more preferred, and -C(=O)O- or a benzene ring is further preferred.

[0165] L 202 For example, preferably, it is a single bond, a straight-chain alkylene group having 1 to 4 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof, and more preferably, it is a single bond, a straight-chain alkylene group having 1 to 3 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof.

[0166] R 204 The alkyl group having 6 to 30 carbon atoms may be any of linear, branched, and 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 further preferably 10 to 25.

[0167] Examples of the straight-chain alkyl group having 6 to 30 carbon atoms include n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, and n-docosyl.

[0168] Examples of the branched alkyl group having 6 to 30 carbon atoms include isohexyl, secondary hexyl, tert-hexyl, isoheptyl, secondary heptyl, tert-heptyl, isooctyl, secondary octyl, tert-octyl, isononyl, secondary nonyl, tert-nonyl, isodecyl, secondary decyl, tert-decyl, isododecyl, secondary dodecyl, tert-dodecyl, tert-tetradecyl, and tert-pentadecyl.

[0169] Examples of the cyclic alkyl group having 6 to 30 carbon atoms include cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, and polycyclic (e.g., bicyclic, tricyclic, spirocyclic) alkyl groups in which these monocyclic alkyl groups are linked.

[0170] R 204 For example, a straight-chain or branched alkyl group having 6 to 30 carbon atoms is preferred, a straight-chain or branched alkyl group having 8 to 28 carbon atoms is more preferred, a straight-chain or branched alkyl group having 9 to 26 carbon atoms is further preferred, and a straight-chain or branched alkyl group having 10 to 25 carbon atoms is further preferred.

[0171] 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).

[0172] [Chemical formula 10]

[0173] Formula (X2-1)

[0174] Formula (X2-2)

[0175] In formula (X2-1) and formula (X2-2), R 203 is a hydrogen atom or a methyl group, 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, and R 204 It is an alkyl group having 6 to 30 carbon atoms.

[0176] R in formula (X2-1) and formula (X2-2) 203 and R 204 Respectively with R in (X2) 203 , L 202 and R 204Same meaning, same approach.

[0177] L in formula (X2-1) 202 For example, a single bond is preferred.

[0178] L in formula (X2-2) 202 For example, preferably, it is a single bond, a straight-chain alkylene group having 1 to 4 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof, and more preferably, it is a single bond, a straight-chain alkylene group having 1 to 3 carbon atoms, -O-, -C(=O)-, -C(=O)O-, or a combination thereof.

[0179] Formation L 202 The shortest link between the atoms in the formula (X2-2) and the benzene ring in R 204 The number of atoms is, for example, preferably 1 or more and 5 or less, more preferably 1 or more and 3 or less, further preferably 1 or 2.

[0180] Specific examples of the unit (X2-1) are shown below, but the unit (X2-1) is not limited thereto. Me is a methyl group.

[0181] [Chemical formula 11]

[0182] <![CDATA[R 203 ]]> <![CDATA[L 202 ]]> <![CDATA[R 204 ]]> X2-1-1 H Single key <![CDATA[n-C6H 13 ]]> X2-1-2 Me Single key <![CDATA[n-C6H 13 ]]> X2-1-3 H Single key <![CDATA[n-C6H 17 ]]> X2-1-4 Me Single key <![CDATA[n-C8H 17 ]]> X2-1-5 H Single key <![CDATA[n-C 12 H 25 ]]> X2-1-6 Me Single key <![CDATA[n-C 12 H 25 ]]> X2-1-7 H Single key <![CDATA[n-C 16 H 31 ]]> X2-1-8 Me Single key <![CDATA[n-C 16 H 31 ]]> X2-1-9 H Single key <![CDATA[n-C 18 H 37 ]]> X2-1-10 Me Single key <![CDATA[n-C 18 H 37 <!-- 15 -->]]> X2-1-11 H Single key <![CDATA[n-C 20 H 41 ]]> X2-1-12 Me Single key <![CDATA[n-C 20 H 41 ]]> X2-1-13 H Single key <![CDATA[n-C 22 H 45 ]]> X2-1-14 Me Single key <![CDATA[n-C 22 H 45 ]]> X2-1-15 H Single key <![CDATA[-CH2-CH(C2H5)-n-C4H9]]> X2-1-16 Me Single key <![CDATA[-CH2-CH(C2H5)-n-C4H9]]>

[0183] [Chemical formula 12]

[0184] <![CDATA[R 203 ]]> <![CDATA[L 202 ]]> <![CDATA[R 204 ]]> X2-1-17 H Single key <![CDATA[n-C 26 H 53 ]]> X2-1-18 Me Single key <![CDATA[n-C 26 H 53 ]]> X2-1-19 H Single key <![CDATA[n-C 28 H 57 ]]> X2-1-20 Me Single key <![CDATA[n-C 28 H 57 ]]> X2-1-21 H Single key <![CDATA[n-C 30 H 61 ]]> X2-1-22 Me Single key <![CDATA[n-C 30 H 61 ]]> X2-1-23 H Single key <![CDATA[-CH2-CH(b-C6H 13 )-n-C8H 17 ]]> X2-1-24 Me Single key <![CDATA[-CH2-CH(n-C6H 13 )-n-C8H 17 ]]>

[0185] Specific examples of the unit (X2-2) are shown below, but the unit (X2-2) is not limited to these.

[0186] [Chemical formula 13]

[0187] <![CDATA[R 203 ]]> <![CDATA[L 202 ]]> <![CDATA[R 204 ]]> X2-2-1 H -O-(C=O)- <![CDATA[n-C6H 13 ]]> X2-2-2 H -O-(C=O)- <![CDATA[n-C7H 15 ]]> X2-2-3 H -O-(C=O)- <![CDATA[n-C 11 H 23 ]]> X2-2-4 H -O-(C=O)- <![CDATA[n-C 17 H 35 ]]> X2-2-5 H -O-(C=O)- <![CDATA[n-C 21 H 43 ]]> X2-2-6 H -O-(C=O)- <![CDATA[-CH(C2H5)-n-C4H9]]> X2-2-7 H -O-(C=O)- <![CDATA[-CH(n-C6H 13 )-n-C8H 17 ]]> X2-2-8 H -O-(C=O)- <![CDATA[n-C 25 H 51 ]]> X2-2-9 H -O-(C=O)- <![CDATA[n-C 27 H 55 ]]> X2-2-10 H -O-(C=O)- <![CDATA[n-C 29 H 59 ]]> X2-2-11 H -O- <![CDATA[n-C 18 H 37 ]]> X2-2-12 H -O- <![CDATA[n-C 22 H 45 ]]> X2-2-13 H -(C=O)O- <![CDATA[n-C 18 H 37 ]]> X2-2-14 H -(C=O)O- <![CDATA[n-C 22 H 45 ]]> X2-2-15 H <![CDATA[-CH2-O-(C=O)-]]> <![CDATA[n-C 17 H 35 ]]> X2-2-16 H <![CDATA[-CH2-O-(C=O)-]]> <![CDATA[n-C 21 H 43 ]]>

[0188] 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 to these.

[0189] [Chemical formula 14]

[0190] <![CDATA[R 201 ]]> <![CDATA[R 202 ]]> <![CDATA[R 203 ]]> <![CDATA[L 201 ]]> <![CDATA[L 202 ]]> <![CDATA[R 204 ]]> X2-E-1 H H H -O-(C=O)- Single key <![CDATA[n-C 11 H 23 ]]> X2-E-2 H H H -O-(C=O)- Single key <![CDATA[n-C 17 H 35 ]]> X2-E-3 H H H -O-(C=O)- Single key <![CDATA[n-C 21 H 43 ]]> X2-E-4 H H H -O-(C=O)- Single key <![CDATA[-CH(n-C6H 13 )-n-C8H 17 ]]> X2-E-5 H H H -O- Single key <![CDATA[n-C 12 H 25 ]]> X2-E-6 H H H -O- Single key <![CDATA[n-C 18 H 37 ]]> X2-E-7 H H H <![CDATA[-CH2-O-]]> Single key <![CDATA[n-C 12 H 26 ]]> X2-E-8 H H H <![CDATA[-CH2-O-]]> Single key <![CDATA[n-C 18 H 37 ]]>

[0191] The resin (X) preferably contains, for example, both a unit represented by the formula (X1) and a unit represented by the formula (X2). By containing both of the above-mentioned units and ensuring the wettability of the resin (X) appropriately, when the coating liquid containing the resin (X) is used for coating in the manufacturing process of the surface protective layer, coating defects caused by bubbles generated in the coating film due to excessively high viscosity of the coating liquid or uneven coating film due to excessively low viscosity of the coating liquid are further suppressed.

[0192] The resin (X) preferably further comprises a unit represented by the following formula (X3). By further comprising a unit represented by the formula (X3) and appropriately ensuring the wettability of the resin (X), when the coating liquid comprising the resin (X) is used for coating in the manufacturing process of the surface protective layer, coating defects caused by bubbles generated in the coating film due to excessively high viscosity of the coating liquid or uneven coating film due to excessively low viscosity of the coating liquid are further suppressed.

[0193] Formula (X3)

[0194] 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 It is an alkylene group having 3 to 10 carbon atoms which may have a substituent.

[0195] R 301 , R 302 and R 303 The alkyl group having 1 to 5 carbon atoms may be any of linear, branched, and cyclic. The alkyl group preferably has 1 to 4 carbon atoms, more preferably 1 to 3 carbon atoms, further preferably 1 or 2, and particularly preferably 1 carbon atom.

[0196] R 301 , R 302 and R 303 Each independently represents, for example, a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0197] 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.

[0198] Examples of the linear alkylene group having 3 to 10 carbon atoms include n-propylene, n-butylene, n-pentylene, n-hexylene, n-heptylene, n-octylene, n-nonylene, and n-decylene.

[0199] Examples of the branched alkylene group having 3 to 10 carbon atoms include isopropylene, isobutylene, sec-butylene, tert-butylene, isopentylene, neopentylene, tert-pentylene, 2-propylpropylene, 2-butylpropylene, 2-ethylpropylene, 2-methylpropylene, 1-ethyl-2-methyl-propylene, 1-propyl-2-methyl-propylene, 1-methyl-2-ethyl-propylene, 1-propylpropylene, 1-butylpropylene, and 2-methyl-pentylene.

[0200] Examples of the cyclic alkylene group having 3 to 10 carbon atoms include cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, cycloheptylene, cyclooctylene, cyclononylene, and cyclodecylene.

[0201] Specific examples of the unit (X3) are shown below, but the unit (X3) is not limited to these.

[0202] [Chemical formula 15]

[0203] <![CDATA[R 301 ]]> <![CDATA[R 302 ]]> <![CDATA[R 303 ]]> <![CDATA[L 301 ]]> X3-1 H H H <![CDATA[-CH2CH2CH2-]]> X3-2 H H H <![CDATA[-CH2CH2CH2CH2CH2-]]> X3-3 H H H <![CDATA[-CH2CH(C4H g )CH2-]]> X3-4 H H H <![CDATA[-CH2CH(C3H7)CH2-]]> X3-5 H H H <![CDATA[-CH2CH(C2H5)CH2-]]> X3-6 H H H <![CDATA[-CH2CH(CH3)CH2-]]> X3-7 H H H <![CDATA[-CH(C2H5)CH(CH3)CH2-]]> X3-8 H H H <![CDATA[-CH(C3H7)CH(CH3)CH2-]]> X3-9 H H H <![CDATA[-CH(CH3)CH(C2H5)CH2-]]> X3-10 H H H <![CDATA[-CH(C3H7)CH2CH2-]]> X3-11 H H H <![CDATA[-CH(C4H9)CH2CH2-]]> X3-12 H H H <![CDATA[-CH2CH2CH2CH(CH3)CH2-]]>

[0204] The unit (X1) contained in the resin (X) may be one kind or two or more kinds.

[0205] The unit (X2) contained in the resin (X) may be one type or two or more types.

[0206] The unit (X3) contained in the resin (X) may be one kind or two or more kinds.

[0207] The resin (X) may contain other structural units in addition to the unit (X1), the unit (X2) and the unit (X3). Hereinafter, the other structural unit is referred to as the unit (X4). The unit (X4) may be one type or two or more types.

[0208] Examples of the unit (X4) include a unit derived from a styrene-based monomer and a unit derived from an acrylic monomer.

[0209] Examples of styrene monomers include styrene, vinylnaphthalene; lower alkyl-substituted styrenes such as α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 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; halogen-substituted styrenes such as p-chlorostyrene, 3,4-dichlorostyrene, p-fluorostyrene, and 2,5-difluorostyrene; and the like.

[0210] Examples of acrylic monomers include (meth)acrylic acid; lower alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, and n-pentyl (meth)acrylate; and benzyl (meth)acrylate. The expression "(meth)acrylic acid" means that it may be either "acrylic acid" or "methacrylic acid".

[0211] Examples of the unit (X4) include units derived from the following monomers.

[0212] Olefins such as isoprene, butylene and butadiene; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone.

[0213] The unit (X4) is, for example, preferably at least one selected from the group consisting of units derived from styrene, units derived from (meth)acrylic acid and units derived from lower alkyl (meth)acrylates, more preferably at least one selected from the group consisting of units derived from styrene and units derived from lower alkyl (meth)acrylates, and still 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.

[0214] The total content of the units (X1), (X2) and (X3) contained in the resin (X) is, for example, preferably 10 mol% to 95 mol%, more preferably 15 mol% to 90 mol%, further preferably 20 mol% to 80 mol%.

[0215] In other words, the content of the units (X3) contained in the resin (X) is, for example, preferably 5 mol% to 90 mol%, more preferably 10 mol% to 85 mol%, further preferably 20 mol% to 80 mol%.

[0216] From the viewpoint of improving the lifespan reduced by wear of the photoreceptor and image quality stability, the mass proportion of the resin (X) in the surface protective layer is, for example, preferably from 0.01 mass % to 10.00 mass %, more preferably from 0.01 mass % to 5 mass %, and further preferably from 0.1 mass % to 1 mass %.

[0217] The mass ratio of the resin (X) in the surface protective layer may be 0.01 mass % or more and 0.30 mass % or less.

[0218] It is known that existing lubricants such as straight-chain polysiloxane compounds, when added to reactive curing films, have a mass ratio of 0.30 mass % or more in the surface protective layer in order to ensure wettability. On the other hand, the resin (X) in the present embodiment has at least one of the units represented by formula (X1) and the units represented by formula (X2), so it is easy to obtain better wettability with a small amount compared to existing lubricants, and the compatibility is also high. Therefore, in the photoreceptor involved in the present embodiment, within the range of 0.01 mass % or more and 0.30 mass % or less, streaky image defects caused by coating defects generated in the manufacturing process of the surface protective layer are also suppressed.

[0219] When the mass ratio of the resin (X) is 0.01 mass % or more, wettability of the surface protective layer can be easily ensured, thereby further suppressing coating film defects. When the mass ratio of the resin (X) is 0.30 mass % or less, in the process of manufacturing the surface protective layer, when coating is performed using a coating liquid containing the resin (X), coating film defects caused by excessively high viscosity of the coating liquid due to excessively high proportion of the resin (X) and the generation of bubbles in the coating film are further suppressed.

[0220] The weight average molecular weight of the resin (X) is, for example, preferably 1,000 or more and 30,000 or less, more preferably 1,000 or more and 10,000 or less, and further preferably 1,000 or more and 8,000 or less.

[0221] When the weight average molecular weight of the resin (X) is 1,000 or more, wettability of the surface protective layer can be easily ensured, thereby further suppressing coating film defects.

[0222] When the weight average molecular weight of the resin (X) is 30,000 or less, coating film defects caused by bubbles in the coating film due to excessively high viscosity of the coating film when coating is performed using a coating liquid containing the resin (X) in the production process of the surface protective layer are further suppressed.

[0223] The molecular weight of the resin (X) is a molecular weight in terms of polystyrene measured by GPC (gel permeation chromatography). GPC is measured by a conventional method using tetrahydrofuran or chloroform as an eluent, for example.

[0224] As the manufacturing method of resin (X), the chain polymerization of monomers providing units (X1), monomers providing units (X2) and monomers providing units (X3) can be enumerated. As the method of chain polymerization, for example, free radical polymerization, coordination polymerization, ionic polymerization (cationic polymerization, anionic polymerization) can be enumerated. Among them, from the viewpoint of versatility such as polymerization control and applicable range, for example, free radical polymerization is preferred.

[0225] [Charge transport material containing reactive groups]

[0226] Examples of the reactive group of the charge transport material containing a reactive group include a chain polymerizable group, an epoxy group, -OH, -OR [wherein R represents an alkyl group], -NH2, -SH, -COOH, -SiR Q1 3-Qn (OR Q2 ) Qn (Among them, R Q1 represents a hydrogen atom, an alkyl group, or a substituted or unsubstituted aryl group, R Q2 represents a hydrogen atom, an alkyl group, a trialkylsilyl group, and Qn represents an integer of 1 to 3) and the like.

[0227] As a chain polymerizable group, there is no particular limitation as long as it is a functional group capable of free radical polymerization, and for example, it is a functional group having a group containing at least a carbon double bond. Specifically, there can be mentioned a group containing at least one selected from vinyl, vinyl ether, vinyl thioether, styryl (phenyl vinyl), acryloyl, methacryloyl and their derivatives. Among them, due to its excellent reactivity, as a chain polymerizable group, for example, it is preferably a group containing at least one selected from vinyl, styryl (phenyl vinyl), acryloyl, methacryloyl and their derivatives.

[0228] The charge transport skeleton of the charge transport material containing a reactive group is not particularly limited as long as it is a known structure in an electrophotographic photoreceptor, and examples thereof include skeletons derived from nitrogen-containing hole transport compounds such as triazine compounds, triarylamine compounds, benzidine compounds, and hydrazone compounds, and structures conjugated with nitrogen atoms. Among them, from the viewpoint of charge transport performance, for example, a skeleton derived from at least one of a triarylamine compound and a triazine compound is preferred.

[0229] The charge transport material having a reactive group may be selected from known materials.

[0230] The charge transport material containing a reactive group may be of one kind or of two or more kinds.

[0231] The charge transport material containing a reactive group preferably includes at least one of the charge transport materials containing a reactive group (hereinafter also referred to as "specific charge transport materials") having at least one substituent selected from the group consisting of -OH, -OCH3, -NH2, -SH and -COOH.

[0232] The cured film of the composition containing the above-mentioned specific charge transport material is unlikely to generate residual OH, water, etc. in the film, and is not easily affected by moisture in the atmosphere when the coating film is formed. Therefore, if it is a cured film of a composition containing these compounds, when the surface protective layer is formed, coating film defects are further suppressed, and streak-like image defects are also further suppressed.

[0233] (Specific charge transport materials)

[0234] The specific charge transport material refers to a charge transport material having at least one substituent selected from the group consisting of -OH, -OCH 3 , -NH 2 , -SH and -COOH.

[0235] The specific charge transport material makes it difficult for residual OH etc. to be generated in the film, and makes it less susceptible to the influence of moisture in the atmosphere when the coating is formed. From the viewpoint of further suppressing coating defects, for example, a charge transport material having at least one substituent selected from -OCH3 and -SH is more preferred.

[0236] As the specific charge transport material, from the viewpoint of suppressing the wear of the foreign matter removing member and suppressing the wear of the electrophotographic photoreceptor, for example, a compound represented by the following general formula (I) is preferred.

[0237] F-((-R 13 -X) n1 (R 14 ) n2 -Y) n3 (I)

[0238] In the general formula (I), F represents an organic group derived from a compound having 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 atom, NH or a sulfur atom, and Y represents -OH, -OCH3, -NH2, -SH or -COOH.

[0239] In the general formula (I), examples of the compound having a hole transporting ability in the organic group derived from the compound having a hole transporting ability representing F include arylamine derivatives. Examples of the arylamine derivatives include triphenylamine derivatives and tetraphenylbenzidine derivatives.

[0240] The compound represented by the general formula (I) is preferably a compound represented by the following general formula (II), for example. The compound represented by the general formula (II) is particularly excellent in charge mobility, stability to oxidation, and the like.

[0241] [Chemical formula 16]

[0242]

[0243] In the general formula (II), Ar 1 To 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 each independently represent 0 or 1, k represents 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 atom, NH or a sulfur atom, and Y represents -OH, -OCH3, -NH2, -SH or -COOH.

[0244] In the general formula (II), "-(-R 13 -X) n1 (R 14 ) n2 -Y" is the same as the general formula (I), R 13 and R 14 Each independently represents a linear or branched alkylene group having 1 to 5 carbon atoms. Furthermore, n1 is preferably 1, for example. Furthermore, n2 is preferably 1, for example. Furthermore, X is preferably an oxygen atom, for example. Furthermore, Y is preferably a hydroxyl group, for example.

[0245] The total number of D in the general formula (II) corresponds to n3 in the general formula (I), and is, for example, preferably 2 or more and 4 or less, and more preferably 3 or more and 4 or less.

[0246] In general formula (I) and general formula (II), when the total number of D in one molecule is 2 to 4, for example, preferably 3 to 4, the crosslinking density increases and a crosslinked film with high strength is more easily obtained.

[0247] 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) together show "-(D)" that can be linked to each of Ar1 to Ar4. C ”.

[0248] [Chemical formula 17]

[0249]

[0250] In formulas (1) to (7), R 15 represents one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group substituted with an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom, and R 16 To R 18 wherein each of them represents one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group substituted by an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, an unsubstituted phenyl group, an aralkyl group having 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 the general formula (II); s represents 0 or 1, respectively; and t represents an integer of 1 to 3.

[0251] Ar in the formula (7) is preferably represented by, for example, the following formula (8) or (9).

[0252] [Chemical formula 18]

[0253]

[0254] In equations (8) to (9), R 19 and R 20 Each of them represents one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group substituted by an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom, and t represents an integer of 1 to 3.

[0255] As Z' in the formula (7), for example, it is preferably represented by any one of the following formulas (10) to (17).

[0256] [Chemical formula 19]

[0257]

[0258] In formulas (10) to (17), R 21 and R 22Each of them represents one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group substituted by an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom, W represents a divalent group, q and r represent an integer of 1 to 10, and t represents an integer of 1 to 3.

[0259] As W in formulae (16) to (17), for example, any of the divalent groups represented by the following formulae (18) to (26) is preferred. In formula (25), however, u represents an integer of 0 or more and 3 or less.

[0260] [Chemical formula 20]

[0261]

[0262] In the general formula (II), when k is 0, Ar 5 For Ar 1 To Ar 4 In the aryl groups of the above formulae (1) to (7) exemplified in the description of 5 It is an arylene group obtained by removing a hydrogen atom from an aryl group of the above formulae (1) to (7).

[0263] Specific examples of the compound represented by the general formula (I) are shown below, but the compound represented by the general formula (I) is not limited to these.

[0264] [Chemical formula 21]

[0265]

[0266] [Chemical formula 22]

[0267]

[0268] [Chemical formula 23]

[0269]

[0270] [Chemical formula 24]

[0271]

[0272] [Chemical formula 25]

[0273]

[0274] [Chemical formula 26]

[0275]

[0276] [Chemical formula 27]

[0277]

[0278] The total content of the specific charge transport material (solid content concentration in the coating liquid) is, for example, preferably 90% by mass or more, and more preferably 94% by mass or more. When the solid content concentration is 90% by mass or more, the deterioration of electrical characteristics is reduced.

[0279] [Curing agent]

[0280] The surface protection layer may be a layer composed of a cured film of a composition containing a curing agent in addition to the resin (X) and the charge transport material containing a reactive group. The curing agent may be one type or two or more types.

[0281] Examples of the curing agent include isocyanate compounds, polyols, guanamine compounds, melamine compounds, etc. Among the above, the curing agent preferably includes 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").

[0282] The cured film of the composition containing at least one compound selected from guanamine compounds and melamine compounds as a curing agent is unlikely to produce residual OH, water, etc. in the film, and is not easily affected by moisture in the atmosphere when the coating film is formed. Therefore, if it is a cured film of a composition containing these compounds, when the surface protective layer is formed, the coating film defects are further suppressed, and the streak-like image defects are also further suppressed. In addition, it is easy to obtain a cured film with a high degree of curing, and the wear resistance is more excellent.

[0283] In particular, the surface protective layer preferably contains, for example, a resin (X); a curing agent having at least one of a guanamine compound and a melamine compound; and at least one of a charge transport material containing a reactive group (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.

[0284] The cured film of the composition comprising a resin (X); a curing agent having at least one of a guanamine compound and a melamine compound; and a specific charge transport material is unlikely to produce residual OH, water, etc. in the film, and is not easily affected by moisture in the atmosphere when the coating film is formed. Therefore, when the cured film of the composition comprising these compounds is formed, coating film defects are further suppressed when the surface protection layer is formed, and streak-like image defects are also further suppressed.

[0285] (Guanamine compound)

[0286] The guanamine compound is a compound having a guanamine skeleton (structure), and examples thereof include acetoguanamine, benzoguanamine, formylguanamine, steroidal guanamine, spiroguanamine, and cyclohexylguanamine.

[0287] As the guanamine compound, in particular, for example, preferably at least one of the compounds represented by the following general formula (A) and its polymers. Here, the polymer is an oligomer in which the compound represented by the general formula (A) is polymerized into a structural unit, and its degree of polymerization is, for example, 2 or more and 200 or less (for example, preferably 2 or more and 100 or less). In addition, the compound represented by the general formula (A) can be used alone, but two or more can also be used in combination. In particular, if two or more compounds represented by the general formula (A) are mixed and used or used as a polymer (oligomer) in which it is set as a structural unit, the solubility in the solvent is improved.

[0288] [Chemical formula 28]

[0289]

[0290] 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. R6 represents a linear or branched alkyl group having 1 to 10 carbon atoms.

[0291] In the general formula (A), the alkyl group representing R1 has a carbon number of 1 to 10, and for example, preferably has a carbon number of 1 to 8, and more preferably has a carbon number of 1 to 5. The alkyl group may be linear or branched.

[0292] In the general formula (A), the carbon number of the phenyl group representing R1 is 6 to 10, and more preferably 6 to 8. Examples of the substituent that may substitute for the phenyl group include a methyl group, an ethyl group, and a propyl group.

[0293] In the general formula (A), the carbon number of the alicyclic hydrocarbon group representing R1 is 4 to 10, for example, more preferably 5 to 8. Examples of the substituent for the alicyclic hydrocarbon group include methyl, ethyl, and propyl.

[0294] In the general formula (A), in "-CH2-O-R6" representing R2 to R5, the carbon number of the alkyl group representing R6 is 1 or more and 10 or less, for example, preferably 1 or more and 8 or less, more preferably 1 or more and 6 or less. In addition, the alkyl group may be linear or branched. For example, methyl, ethyl, butyl, etc. are preferred.

[0295] As the compound represented by the general formula (A), for example, preferably, R1 represents a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, and R2 to R5 each independently represent -CH2-O-R6. Furthermore, R6 is preferably selected from, for example, a methyl group or an n-butyl group.

[0296] The compound represented by the general formula (A) can be synthesized, for example, using guanamine and formaldehyde by a known method (for example, The Chemical Society of Japan, Experimental Chemistry Lectures, 4th edition, Vol. 28, p. 430).

[0297] As specific examples of compounds represented by general formula (A), exemplified compounds (A)-1 to (A)-42 are shown below, but the present embodiment is not limited thereto. Furthermore, the following specific examples are monomers, but may also be polymers (oligomers) in which these monomers are set as structural units. In addition, in the following exemplified compounds, "Me" represents a methyl group, "Bu" represents a butyl group, and "Ph" represents a phenyl group.

[0298] [Chemical formula 29]

[0299]

[0300] [Chemical formula 30]

[0301]

[0302] [Chemical formula 31]

[0303]

[0304] [Chemical formula 32]

[0305]

[0306] In addition, commercially available products of the compound represented by the general formula (A) include, for example, 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 DIC Corporation), NICALAC BL-60, NICALAC BX-4000 (all manufactured by NIPPON CARBIDE INDUSTRIES CO., INC.), and the like.

[0307] Furthermore, after synthesis or commercial purchase, the compound represented by the general formula (A) (including polymers) can be dissolved in a suitable solvent such as toluene, xylene, ethyl acetate, etc., and washed with distilled water, ion exchange water, etc., in order to eliminate the influence of residual catalyst, or it can be treated with ion exchange resin to remove it.

[0308] (Melamine compounds)

[0309] As a melamine compound, for example, a melamine skeleton (structure), in particular, preferably at least one of the compounds represented by the following general formula (B) and its polymers. Here, similarly to the general formula (A), the polymer is an oligomer formed by polymerizing the compound represented by the general formula (B) as a structural unit, and its degree of polymerization is, for example, 2 or more and 200 or less (for example, preferably 2 or more and 100 or less). In addition, the compound represented by the general formula (B) or its polymer can be used alone or in combination of two or more. And, it can also be used in combination with the compound represented by the general formula (A) or its polymer. In particular, if two or more compounds represented by the general formula (B) are mixed and used, or used as a polymer (oligomer) in which it is set as a structural unit, the solubility in the solvent is improved.

[0310] [Chemical formula 33]

[0311]

[0312] In the general formula (B), R 6 To R 11 Each independently represents a hydrogen atom, -CH2-OH, -CH2-OR 12 、-OR 12 , R 12 It represents an optionally branched alkyl group having a carbon number of 1 to 5. Examples of the alkyl group include a methyl group, an ethyl group, and a butyl group.

[0313] The compound represented by the general formula (B) is synthesized, for example, using melamine and formaldehyde by a known method (for example, synthesized in the same manner as the melamine resin in Experimental Chemistry Lectures, 4th edition, Vol. 28, p. 430).

[0314] Hereinafter, as specific examples of compounds represented by general formula (B), exemplary compounds (B)-1 to exemplary compounds (B)-8 are shown, but the present embodiment is not limited thereto. Furthermore, the following specific examples represent monomers, but may also be polymers (oligomers) in which these are used as structural units.

[0315] [Chemical formula 34]

[0316]

[0317] Examples of commercially available products of the compound represented by the general formula (B) include Super Melami No. 90 (manufactured by NOFCORPORATION), SUPER BECKAMINE (R) TD-139-60 (manufactured by DIC Corporation), U-VAN 2020 (manufactured by Mitsui Chemicals), Sumitex Resin M-3 (manufactured by Sumitomo Chemical Industry Company Limited), and NICALAC MW-30 (manufactured by NIPPON CARBIDE INDUSTRIES CO., INC.).

[0318] Furthermore, after synthesis or commercial purchase, the compound represented by the general formula (B) (including polymers) can be dissolved in a suitable solvent such as toluene, xylene, ethyl acetate, etc., and washed with distilled water, ion exchange water, etc., in order to eliminate the influence of residual catalyst, or it can be treated with ion exchange resin to remove it.

[0319] The proportion of the guanamine compound and the melamine compound in the entire curing agent is, for example, preferably 80 mass % or more, more preferably 85 mass % or more and 100 mass % or less, and further preferably 90 mass % or more and 100 mass % or less.

[0320] The total content (solid content concentration in the coating liquid) of the guanamine compound (for example, preferably a compound represented by the general formula (A)) and the melamine compound (for example, preferably a compound represented by the 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. If the solid content concentration is 0.1% by mass or more, it tends to be easy to form a dense film and the strength and film-forming properties are further improved. If the solid content concentration is 5% by mass or less, during film formation, uneven coating is suppressed and the film-forming properties are further improved.

[0321] The composition constituting the surface protection layer, ie, the cured film, may further contain a well-known additive such as a leveling agent (for example, a silicone-based leveling agent).

[0322] The formation of the surface protection layer is not particularly limited, and a known formation method can be used, but for example, a coating film of a surface protection layer-forming coating liquid is formed by adding the above-mentioned components to a solvent, drying the coating film, and performing a curing treatment such as heating as required. At this time, the surface protection layer can be further prevented from peeling off from the charge transport layer by changing the leveling agent as needed to increase the bonding effect.

[0323] As the solvent used for preparing the coating liquid for forming the surface protective layer, there can be mentioned aromatic solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; ether solvents such as tetrahydrofuran and dioxane; cellosolve solvents such as ethylene glycol monomethyl ether; alcohol solvents such as isopropyl alcohol and butanol, etc. These solvents can be used alone or in combination of two or more.

[0324] In addition, the coating liquid for forming the surface protective layer may be a solvent-free coating liquid.

[0325] 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 common methods such as dip coating, push coating, wire bar coating, spray coating, blade coating, air knife coating, and curtain coating.

[0326] The film thickness of the surface protection layer is preferably set within the range of, for example, 1 μm to 20 μm, and more preferably within the range of 2 μm to 10 μm.

[0327] 〔Conductive substrate〕

[0328] As the conductive substrate, for example, metal plates, metal drums, and metal belts containing metals (aluminum, copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold, platinum, etc.) or alloys (stainless steel, etc.) can be cited. In addition, as the conductive substrate, for example, conductive compounds (such as conductive polymers, indium oxide, etc.); paper coated, vapor-deposited, or laminated with metals (such as aluminum, palladium, gold, etc.) or alloys; resin films; belts, etc. Here, "conductive" means that the volume resistivity is less than 1×10 13 Ω·cm.

[0329] When the electrophotographic photoreceptor is used in a laser printer, the surface of the conductive substrate is preferably roughened to 0.04 μm or more and 0.5 μm or less in terms of center line average roughness Ra for the purpose of suppressing interference fringes generated when irradiating a laser beam. When incoherent light is used as a light source, roughening to prevent interference fringes is not particularly necessary, but the generation of defects caused by the unevenness of the conductive substrate surface is suppressed, so it is suitable for a longer life.

[0330] Examples of the roughening method include wet grinding in which an abrasive is suspended in water and sprayed onto the conductive substrate, centerless grinding in which the conductive substrate is pressed against a rotating grinding wheel and continuously ground, and anodizing.

[0331] As a method of roughening, there is also a method in which, without roughening the surface of the conductive substrate, conductive or semiconductive powder is dispersed in a resin to form a layer on the surface of the conductive substrate, and roughening is performed by particles dispersed in the layer.

[0332] The roughening treatment based on anodization is to use a metal (e.g., aluminum) conductive substrate as an anode and perform anodization in an electrolyte solution, thereby forming an oxide film on the surface of the conductive substrate. As an electrolyte solution, for example, sulfuric acid solution, oxalic acid solution, etc. can be cited. However, the porous anodized film formed by anodization has chemical activity in its original state, is easily contaminated, and the resistance change caused by the environment is also large. Therefore, for example, it is preferred that the porous anodized film is blocked by the volume expansion caused by water and reaction in pressurized water vapor or boiling water (metal salts such as nickel can be added) to change the micropores of the oxide film to the sealing treatment of a more stable hydrated oxide.

[0333] The film thickness of the anodized film is preferably, for example, 0.3 μm or more and 15 μm or less. When the film thickness is within the above range, the barrier property against injection tends to function and the increase in residual potential due to repeated use tends to be suppressed.

[0334] The conductive substrate may be subjected to a treatment using an acidic treatment liquid or a boehmite treatment.

[0335] The treatment based on the acidic treatment solution is implemented, for example, in the following manner. First, an acidic treatment solution containing phosphoric acid, chromic acid and hydrofluoric acid is prepared. The proportion of phosphoric acid, chromic acid and hydrofluoric acid in the acidic treatment solution is, for example, in the range of 10 mass % to 11 mass % for phosphoric acid, in the range of 3 mass % to 5 mass % for chromic acid, and in the range of 0.5 mass % to 2 mass % for hydrofluoric acid, and the concentration of the total amount of these acids is preferably in the range of 13.5 mass % to 18 mass %. The treatment temperature is, for example, preferably 42° C. to 48° C. The film thickness of the film is, for example, preferably 0.3 μm to 15 μm.

[0336] The boehmite treatment is carried out, for example, by immersing in pure water at 90°C to 100°C for 5 to 60 minutes or contacting in heated water vapor at 90°C to 120°C for 5 to 60 minutes. The film thickness of the film is preferably 0.1 μm to 5 μm. An anodizing treatment can be further performed using an electrolyte solution with low film solubility such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, or citrate.

[0337] 〔Undercoating〕

[0338] The undercoat layer is, for example, a layer containing inorganic particles and a binder resin.

[0339] Examples of inorganic particles include powder resistance (volume resistivity) of 1×10 2 Ω·cm or more and 1×1011 Inorganic particles with a particle size of less than Ω·cm.

[0340] Among them, as the inorganic particles having the above resistance value, for example, metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, and zirconium oxide particles are preferred, and zinc oxide particles are particularly preferred.

[0341] The specific surface area of ​​the inorganic particles based on the BET method is preferably 10 m 2 / g or above.

[0342] The volume average particle diameter of the inorganic particles is, for example, preferably 50 nm or more and 2000 nm or less (for example, preferably 60 nm or more and 1000 nm or less).

[0343] The content of the inorganic particles is, for example, preferably 10% by mass or more and 80% by mass or less, and more preferably 40% by mass or more and 80% by mass or less, based on the binder resin.

[0344] The inorganic particles may be subjected to surface treatment. Two or more inorganic particles having different surface treatments or particles having different particle sizes may be used in combination.

[0345] Examples of the surface treatment agent include silane coupling agents, titanate coupling agents, aluminum coupling agents, surfactants, etc. In particular, for example, a silane coupling agent is preferred, and a silane coupling agent having an amino group is more preferred.

[0346] Examples of the silane coupling agent having an amino group include, but are not limited to, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, and N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane.

[0347] Silane coupling agents can be mixed and used in two or more ways. For example, silane coupling agents with amino groups can be used in combination with other silane coupling agents. As other silane coupling agents, for example, vinyl trimethoxysilane, 3-methacryloxypropyl-tris (2-methoxyethoxy) silane, 2- (3,4-epoxycyclohexyl) ethyl trimethoxysilane, 3-glycidoxypropyl trimethoxysilane, vinyl triacetoxysilane, 3-mercaptopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, N-2- (aminoethyl) -3-aminopropyl trimethoxysilane, N-2- (aminoethyl) -3-aminopropyl methyl dimethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyl triethoxysilane, 3-chloropropyl trimethoxysilane, etc. can be cited, but it is not limited thereto.

[0348] The surface treatment method using the surface treatment agent may be any method as long as it is a known method, and may be either a dry method or a wet method.

[0349] The treatment amount of the surface treatment agent is preferably, for example, 0.5% by mass or more and 10% by mass or less relative to the inorganic particles.

[0350] Here, from the viewpoint of improving the long-term stability of electrical characteristics and carrier blocking properties, the undercoat layer preferably contains an electron accepting compound (acceptor compound) together with inorganic particles, for example.

[0351] As electron accepting compounds, for example, there can be mentioned quinone compounds such as chloranil and tetrabromobenzoquinone; tetracyanobenzoquinone dimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone; oxadiazole compounds such as 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole, 2,5-bis(4-naphthyl)-1,3,4-oxadiazole, and 2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole; xanthone compounds; thiophene compounds; diphenoquinone compounds such as 3,3',5,5'-tetra-tert-butyldiphenoquinone; benzophenone compounds; and other electron transporting substances.

[0352] In particular, the electron accepting compound is preferably a compound having an anthraquinone structure. The compound having an anthraquinone structure is preferably a hydroxyanthraquinone compound, an aminoanthraquinone compound, an aminohydroxyanthraquinone compound, and more specifically, anthraquinone, alizarin, quinizarin, anthraquinone, purpurin, and the like.

[0353] The electron accepting compound may be contained in the undercoat layer in a dispersed state together with the inorganic particles, or may be contained in the undercoat layer in a state of being attached to the surfaces of the inorganic particles.

[0354] Examples of a method for attaching the electron accepting compound to the surface of the inorganic particles include a dry method and a wet method.

[0355] The dry method is, for example, a method in which an electron accepting compound or an electron accepting compound dissolved in an organic solvent is directly added dropwise while stirring the inorganic particles by a mixer with a large shear force, and the electron accepting compound is sprayed together with dry air or nitrogen to attach the electron accepting compound to the surface of the inorganic particles. When the electron accepting compound is added dropwise or sprayed, for example, it can be done at a temperature below the boiling point of the solvent. After the electron accepting compound is added dropwise or sprayed, sintering can also be performed at a condition of 100°C or above. There is no particular limitation on the sintering temperature and time as long as the electrophotographic properties can be obtained.

[0356] The wet method is, for example, a method in which inorganic particles are dispersed in a solvent by stirring, ultrasonic waves, a sand mill, a grinder, a ball mill, etc., and after adding an electron accepting compound and stirring or dispersing, the solvent is removed to attach the electron accepting compound to the surface of the inorganic particles. The solvent removal method is, for example, to remove the solvent by filtering or distilling. After removing the solvent, sintering can also be performed at a condition of 100°C or above. Sintering is not particularly limited as long as the temperature and time are such that electronic photographic properties can be obtained. In the wet method, the water content of the inorganic particles can be removed before adding the electron accepting compound. As examples thereof, a method of removing the water content in the solvent while stirring and heating the water content, and a method of removing the water content by azeotropic reaction with the solvent can be cited.

[0357] The electron accepting compound may be attached before or after the inorganic particles are surface treated with a surface treatment agent, or the electron accepting compound may be attached and the surface treated with a surface treatment agent may be simultaneously performed.

[0358] The content of the electron accepting compound may be, for example, 0.01 mass % to 20 mass % inclusive, and preferably 0.01 mass % to 10 mass % inclusive, based on the inorganic particles.

[0359] Examples of the binder resin used in the lower coating layer include acetal resins (e.g., polyvinyl butyral), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, unsaturated polyester resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, urea resins, phenolic resins, phenol-formaldehyde resins, melamine resins, urethane resins, alkyd resins, epoxy resins and other well-known polymer compounds; zirconium chelate compounds; titanium chelate compounds; aluminum chelate compounds; titanium alkoxide compounds; organic titanium compounds; silane coupling agents and other well-known materials.

[0360] Examples of the binder resin used in the undercoat layer include a charge transporting resin having a charge transporting group, and a conductive resin (for example, polyaniline).

[0361] Among them, the binding resin used in the lower coating layer is preferably a resin that is insoluble in the coating solvent in the upper layer, and is particularly preferably a resin obtained by reacting at least one resin selected from the group consisting of thermosetting resins such as urea resin, phenolic resin, phenol-formaldehyde resin, melamine resin, urethane resin, unsaturated polyester resin, alkyd resin, epoxy resin, polyamide resin, polyester resin, polyether resin, methacrylic resin, acrylic resin, polyvinyl alcohol resin and polyvinyl acetal resin with a curing agent.

[0362] When two or more of these binder resins are used in combination, the mixing ratio is set as necessary.

[0363] In order to improve electrical characteristics, improve environmental stability, and improve image quality, various additives may be included in the undercoat layer.

[0364] As additives, there can be mentioned known materials such as polycyclic condensation type, azo type and other electron transporting pigments, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, silane coupling agents, etc. As mentioned above, silane coupling agents are used for surface treatment of inorganic particles, but can also be added to the undercoat layer as an additive.

[0365] Examples of the silane coupling agent as an additive 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, and 3-chloropropyltrimethoxysilane.

[0366] Examples of the zirconium chelate compound include zirconium butoxide, zirconium ethyl acetoacetate, zirconium triethanolamine, zirconium acetylacetonate butoxide, zirconium ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octanoate, zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, zirconium methacrylate butoxide, zirconium stearate butoxide, and zirconium isostearate butoxide.

[0367] Examples of the titanium chelate compound include tetraisopropyl titanate, tetra-n-butyl titanate, butyl titanate dimer, tetra(2-ethylhexyl) titanate, titanium acetylacetonate, titanium polyacetylacetonate, titanium octanediol, ammonium lactate titanium, titanium lactate, ethyl lactate titanium, triethanolamine titanium, and polyhydroxystearate titanium.

[0368] Examples of the aluminum chelate compound include aluminum isopropoxide, monobutoxyaluminum diisopropoxide, aluminum butoxide, diethyl acetoacetate aluminum diisopropoxide, and tris(ethyl acetoacetate)aluminum.

[0369] These additives may be used alone or in the form of a mixture or polycondensate of a plurality of compounds.

[0370] The undercoat layer may have a Vickers hardness of 35 or more, for example.

[0371] In order to suppress interference moire images, the surface roughness (ten-point average roughness) of the undercoat layer is preferably adjusted to, for example, 1 / (4n) (n is the refractive index of the upper layer) to 1 / 2 of the exposure laser wavelength λ used.

[0372] In order to adjust the surface roughness, resin particles or the like may be added to the undercoat layer. Examples of the resin particles include silicone resin particles and cross-linked polymethacrylate methyl resin particles. In addition, in order to adjust the surface roughness, the surface of the undercoat layer may be ground. Examples of the grinding method include polishing, sandblasting, wet grinding, grinding, and the like.

[0373] The formation of the undercoat layer is not particularly limited and can be performed by a known formation method. For example, the undercoat layer can be formed by forming a coating film of an undercoat layer-forming coating liquid prepared by adding the above-mentioned components to a solvent, drying the coating film, and heating as necessary.

[0374] Examples of the solvent used for preparing the coating solution for forming an undercoat layer include known organic solvents such as alcohol solvents, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, ketone solvents, ketone alcohol solvents, ether solvents, and ester solvents.

[0375] Specific examples of these solvents include common organic solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, dichloromethane, chloroform, chlorobenzene, and toluene.

[0376] Examples of a method for dispersing the inorganic particles when preparing the coating liquid for forming an undercoat layer include known methods such as a roll mill, a ball mill, a vibration ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker.

[0377] Examples of a method for applying the coating liquid for forming an undercoat layer onto the conductive substrate include common methods such as blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0378] The average thickness of the undercoat layer is, for example, preferably 10 μm or more and 50 μm or less, and more preferably 15 μm or more and 40 μm or less.

[0379] 〔Middle layer〕

[0380] An intermediate layer may be provided between the undercoat layer and the photosensitive layer.

[0381] The intermediate layer is, for example, a layer containing a resin. Examples of the resin used in the intermediate layer include acetal resins (e.g., polyvinyl butyral), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, phenol-formaldehyde resins, melamine resins and other polymer compounds.

[0382] The intermediate layer may be a layer containing an organic metal compound. Examples of the organic metal compound used in the intermediate layer include organic metal compounds containing metal atoms such as zirconium, titanium, aluminum, manganese, and silicon.

[0383] The compounds used in the intermediate layer may be used alone or as a mixture or polycondensate of a plurality of compounds.

[0384] Among them, the intermediate layer is preferably a layer containing an organic metal compound containing zirconium atoms or silicon atoms, for example.

[0385] The formation of the intermediate layer is not particularly limited and can be performed by a known formation method. For example, the intermediate layer can be formed by forming a coating film of an intermediate layer-forming coating liquid prepared by adding the above components to a solvent, drying the coating film, and heating as necessary.

[0386] As a coating method for forming the intermediate layer, a common method such as a dip coating method, a push coating method, a wire bar coating method, a spray coating method, a blade coating method, an air knife coating method, a curtain coating method, etc. can be used.

[0387] The average thickness of the intermediate layer is preferably, for example, 0.1 μm or more and 3 μm or less. The intermediate layer can be used as an undercoat layer.

[0388] 〔Charge generation layer〕

[0389] The charge generating layer is, for example, a layer containing a charge generating material and a binder resin. Furthermore, the charge generating layer may be a vapor-deposited layer of the charge generating material. The vapor-deposited layer of the charge generating material is suitable for the case where an incoherent light source such as an LED (Light Emitting Diode) or an organic EL (Electro-luminescence) image array is used.

[0390] Examples of the charge generating material include azo pigments such as disazo and trisazo; condensed ring aromatic pigments such as dibromoanthraquinone; perylene pigments; pyrrolopyrrole pigments; phthalocyanine pigments; zinc oxide; and trigonal selenium.

[0391] Among them, in order to cope with laser exposure in the near-infrared region, metal phthalocyanine pigments or metal-free phthalocyanine pigments are preferably used as charge generating materials, and more specifically, hydroxygallium phthalocyanine, chlorogallium phthalocyanine, dichlorotin phthalocyanine, and oxytitanium phthalocyanine are more preferred.

[0392] On the other hand, in order to cope with laser exposure in the near-ultraviolet region, preferred charge generating materials include condensed ring aromatic pigments such as dibromoanthraquinone, thioindigo pigments, porphyrazine compounds, zinc oxide, trigonal selenium, and disazo pigments.

[0393] The above-mentioned charge generating material can be used even when an incoherent light source such as an LED or an organic EL array having a central wavelength of light emitted in the range of 450 nm to 780 nm is used.

[0394] In contrast, when n-type semiconductors such as condensed aromatic pigments, perylene pigments, and azo pigments are used as charge generating materials, dark current is less likely to be generated, and image defects called black spots can be suppressed even in thin films. The n-type is determined by the polarity of the photocurrent flowing using the commonly used time-of-flight method, and semiconductors that are more likely to flow with electrons as carriers than holes are defined as n-type.

[0395] The binder resin used in the charge generating layer can be selected from a wide range of insulating resins, and can be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinyl anthracene, polyvinyl pyrene, and polysilane.

[0396] Examples of the binder resin include polyvinyl butyral resin, polyarylate resin (condensation products of bisphenols and aromatic dicarboxylic acids), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin, polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, etc. Here, "insulation" means that the volume resistivity is 1×10 13 Ω·cm or more.

[0397] These binder resins may be used alone or in combination of two or more.

[0398] The mixing ratio of the charge generating material to the binder resin is preferably in the range of 10:1 to 1:10, for example, in terms of mass ratio.

[0399] Other known additives may be contained in the charge generating layer.

[0400] The formation of the charge generating layer is not particularly limited, and a known formation method can be used, but for example, a coating film of a charge generating layer-forming coating liquid in which the above-mentioned components are added to a solvent is formed, the coating film is dried, and heating is performed as needed. The charge generating layer can be formed by vapor deposition of the charge generating material. The formation of the charge generating layer by vapor deposition is particularly suitable for the case where, for example, a condensed ring aromatic pigment or a perylene pigment is used as the charge generating material.

[0401] Examples of the solvent used for preparing the charge generating layer-forming coating solution include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, dichloromethane, chloroform, chlorobenzene, toluene, etc. These solvents may be used alone or in combination of two or more.

[0402] As a method for dispersing particles (e.g., charge generating material) in the coating liquid for forming the charge generating layer, for example, a medium disperser such as a ball mill, a vibrating ball mill, a grinder, a sand mill, a horizontal sand mill, or a stirrer, an ultrasonic disperser, a roll mill, a high-pressure homogenizer, or a medium-free disperser can be used. As a high-pressure homogenizer, for example, a collision method in which the dispersion is dispersed by liquid-liquid collision or liquid-wall collision under high pressure, and a penetration method in which the dispersion is dispersed by penetrating a fine flow path under high pressure, etc. can be cited.

[0403] When performing the dispersion, it is effective to set the average particle size of the charge generating material in the charge generating layer forming coating liquid to 0.5 μm or less, for example, preferably 0.3 μm or less, more preferably 0.15 μm or less.

[0404] Examples of a method for applying the charge generating layer forming coating liquid onto the undercoat layer (or the intermediate layer) include common methods such as blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0405] The average thickness of the charge generating layer is, for example, preferably 0.1 μm or more and 5.0 μm or less, and more preferably 0.2 μm or more and 2.0 μm or less.

[0406] 〔Charge transport layer〕

[0407] The charge transport layer is, for example, a layer containing a charge transport material and a binder resin. The charge transport layer may be a layer containing a polymer charge transport material.

[0408] As charge transport materials, there can be cited quinone compounds such as p-benzoquinone, chloranil, tetrabromobenzoquinone, anthraquinone, etc.; tetracyanoterephthalene compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone; anthrone compounds; benzophenone compounds; cyanoethylene compounds; vinyl compounds and other electron transport compounds. As charge transport materials, there can also be cited triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted vinyl compounds, stilbene compounds, anthracene compounds, hydrazone compounds and other hole transport compounds. These charge transport materials can be used alone or in combination of two or more, but are not limited thereto.

[0409] From the viewpoint of charge mobility, the charge transport material is preferably, for example, a triarylamine derivative represented by the following structural formula (a-1) and a benzidine derivative represented by the following structural formula (a-2).

[0410] [Chemical formula 35]

[0411]

[0412] In the structural formula (a-1), Ar T1 ,Ar T2 and Ar T3 Each independently represents a substituted or unsubstituted aryl group, -C6H4-C(R T4 )=C(R T5 )(R T6 ) or -C6H4-CH=CH-CH=C(R T7 )(R T8 ). T4 , R T5 , R T6 , R T7 and R T8 Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group.

[0413] Examples of substituents of the above groups include halogen atoms, alkyl groups having 1 to 5 carbon atoms, and alkoxy groups having 1 to 5 carbon atoms. In addition, examples of substituents of the above groups include substituted amino groups substituted with alkyl groups having 1 to 3 carbon atoms.

[0414] [Chemical formula 36]

[0415]

[0416] In the 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 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an amino group substituted by an alkyl group having 1 to 2 carbon atoms, a substituted or unsubstituted aryl group, -C(R T12 )=C(R T13 )(R T14 ) or -CH=CH-CH=C(R T15 )(R T16 ), R T12 , R T13 , R T14 , R T15 and R T16 Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Tm1, Tm2, ​​Tn1, and Tn2 each independently represent an integer of 0 or more and 2 or less.

[0417] Examples of substituents of the above groups include halogen atoms, alkyl groups having 1 to 5 carbon atoms, and alkoxy groups having 1 to 5 carbon atoms. In addition, examples of substituents of the above groups include substituted amino groups substituted with alkyl groups having 1 to 3 carbon atoms.

[0418] Here, from the viewpoint of charge mobility, among the triarylamine derivatives represented by the structural formula (a-1) and the benzidine derivatives represented by the structural formula (a-2), for example, those having "-C6H4-CH=CH-CH=C(R T7 )(R T8 )" and triarylamine derivatives having "-CH=CH-CH=C(R T15 )(R T16 )" benzidine derivatives.

[0419] As the polymer charge transport material, known materials having charge transport properties such as poly-N-vinyl carbazole and polysilane can be cited. In particular, polyester-based polymer charge transport materials are particularly preferred. The polymer charge transport material can be used alone or in combination with a binder resin.

[0420] The binder resin used in the charge transport layer can be polycarbonate resin, polyester resin, polyarylate resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinyl carbazole, polysilane, etc. Among them, as a binder resin, for example, preferably polycarbonate resin or polyarylate resin. These binder resins are used alone or in combination of two or more.

[0421] The mixing ratio of the charge transport material to the binder resin is preferably, for example, 10:1 to 1:5 in terms of mass ratio.

[0422] Other well-known additives may be contained in the charge transport layer.

[0423] The charge transport layer can be formed by any known method without particular limitation, but can be formed by, for example, forming a coating film of a charge transport layer-forming coating liquid prepared by adding the above components to a solvent, drying the coating film, and heating as necessary.

[0424] As the solvent for preparing the coating solution for forming the charge transport layer, there can be mentioned aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene; ketones such as acetone and 2-butanone; halogenated aliphatic hydrocarbons such as dichloromethane, chloroform, and dichloroethane; cyclic or linear ethers such as tetrahydrofuran and diethyl ether, and other common organic solvents. These solvents can be used alone or in combination of two or more.

[0425] Examples of a coating method for coating the charge transport layer-forming coating liquid on the charge generating layer include common methods such as blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0426] <Image forming apparatus, process cartridge>

[0427] The image forming device involved in this embodiment comprises the electrophotographic photoreceptor involved in this embodiment, a charging device for charging the surface of the electrophotographic photoreceptor, an electrostatic latent image forming device for forming an electrostatic latent image on the surface of the charged electrophotographic photoreceptor, a developing device for developing the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image, and a transfer device for transferring the toner image to the surface of a recording medium.

[0428] The image forming device involved in this embodiment is applicable to the following well-known image forming devices: a device equipped with a fixing device for fixing the toner image transferred to the surface of a recording medium; a device using a direct transfer method for directly transferring the toner image formed on the surface of an electrophotographic photosensitive body to the recording medium; a device using an intermediate transfer method for transferring the toner image formed on the surface of an electrophotographic photosensitive body once to the surface of an intermediate transfer body, and for a second time transferring the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium; a device equipped with a cleaning device for cleaning the surface of the electrophotographic photosensitive body after transferring the toner image but before charging; a device equipped with a static elimination device for removing static electricity by irradiating the surface of the electrophotographic photosensitive body with static elimination light after transferring the toner image and before charging; and a device equipped with an electrophotographic photosensitive body heating component for increasing the temperature of the electrophotographic photosensitive body and lowering the relative temperature, etc.

[0429] In the case of an intermediate transfer type device, the transfer device, for example, is applicable to the following structure, which has an intermediate transfer body that transfers the toner image on the surface, a primary transfer device that transfers the toner image formed on the surface of the electronic photographic photosensitive body to the surface of the intermediate transfer body for the first time, and a secondary transfer device that transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium for the second time.

[0430] The transfer device, for example, preferably includes an intermediate transfer belt, a scraper 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 component that transfers a colorant image formed on the surface of an image retaining body to the outer peripheral surface of the intermediate transfer belt, and a secondary transfer device having a secondary transfer component that is configured to contact the outer peripheral surface of the intermediate transfer belt and transfers the colorant image transferred to the outer peripheral surface of the intermediate transfer belt to the surface of a recording medium for a second time.

[0431] The transfer pressure during the primary transfer is, for example, preferably a linear pressure of 17 g / cm or less, more preferably a linear pressure of 15 g / cm or less, and still more preferably a linear pressure of 10 g / cm to 12 g / cm or less.

[0432] If the transfer pressure in the first transfer is a linear pressure of less than 17 g / cm, the load applied to the interface between the charge transport layer and the surface protection layer is suppressed to a smaller value when transferring from the electronic photographic photoreceptor, thereby further suppressing the peeling of the surface protection layer from the charge transport layer due to the reaction to the load.

[0433] When the transfer pressure in the primary transfer is a linear pressure of 10 g / cm or more, image defects due to transfer failure can be reduced when transferring from an electrophotographic photoreceptor.

[0434] The image forming apparatus according to the present embodiment may be any of a dry developing system image forming apparatus and a wet developing system (development system using a liquid developer) image forming apparatus.

[0435] In the image forming apparatus according to the present embodiment, for example, the portion having the electrophotographic photoreceptor may be a cartridge structure (processing cartridge) that is detachable from the image forming apparatus. As the processing cartridge, for example, a processing cartridge having the electrophotographic photoreceptor according to the present embodiment is preferably used. In the processing cartridge, in addition to the electrophotographic photoreceptor, for example, 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 may be provided.

[0436] An example of the image forming apparatus according to the present embodiment is shown below, but the present invention is not limited thereto. The main parts shown in the drawings will be described, and descriptions of other parts will be omitted.

[0437] Picture 2 It is a schematic configuration diagram showing an example of the image forming apparatus according to the present embodiment.

[0438] like Picture 2 As shown, the image forming apparatus 100 according to the present embodiment includes a process box 300 having 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 arranged at a position capable of exposing the electrophotographic photoreceptor 7 from the opening of the process box 300, and the transfer device 40 is arranged at a position opposed to the electrophotographic photoreceptor 7 with the intermediate transfer body 50 interposed therebetween, and the intermediate transfer body 50 is arranged so that a part thereof contacts the electrophotographic photoreceptor 7. Although not shown in the figure, a secondary transfer device is further provided for transferring the toner image transferred to the intermediate transfer body 50 to a recording medium (e.g., paper). The intermediate transfer body 50, the transfer device 40 (a primary transfer device), and the secondary transfer device (not shown in the figure) correspond to an example of a transfer device.

[0439] Picture 2 The process box 300 in the embodiment integrally supports the electrophotographic photoreceptor 7, the charging device 8 (an example of a charging device), the developing device 11 (an example of a developing device), and the cleaning device 13 (an example of a cleaning device) in a housing. The cleaning device 13 has a cleaning blade (an example of a cleaning member) 131, and the cleaning blade 131 is configured to contact the surface of the electrophotographic photoreceptor 7. The cleaning member may be a conductive or insulating fibrous member instead of the cleaning blade 131, and may be used alone or in combination with the cleaning blade 131.

[0440] exist Picture 2In the example shown, as the image forming apparatus, a fibrous member 132 (roller-shaped) for supplying lubricant 14 to the surface of electrophotographic photoreceptor 7 and a fibrous member 133 (flat brush-shaped) for assisting cleaning are provided, but these may be arranged as necessary.

[0441] Hereinafter, each structure of the image forming apparatus according to the present embodiment will be described.

[0442] -Electrified Devices-

[0443] As the charging device 8, for example, a contact type charging device such as a charging roller, a charging brush, a charging film, a charging rubber blade, a charging hose, etc. using conductive or semi-conductive charging can be used. In addition, a non-contact type roller charging device, a scorotron charging device or a corotron charging device using corona discharge, etc., which are known per se, can also be used.

[0444] -Exposure device-

[0445] As the exposure device 9, for example, there can be cited an optical system device that exposes semiconductor laser, LED light, liquid crystal shutter light, etc. on the surface of the electrophotographic photoreceptor 7 to a prescribed pattern. The wavelength of the light source is set within the spectral sensitivity region of the electrophotographic photoreceptor. As the wavelength of the semiconductor laser, near-infrared light with an oscillation wavelength near 780nm is the mainstream. However, it is not limited to this wavelength. As an oscillation wavelength laser or a blue laser in the 600nm band, a laser with an oscillation wavelength in the range of more than 400nm and less than 450nm can also be used. In addition, a surface-emitting laser light source of the type that can output multiple beams in order to form a color image is also effective.

[0446] -Developing device-

[0447] As the developing device 11, for example, a general developing device that develops by contact or non-contact with a developer can be cited. As the developing device 11, there is no particular limitation as long as it has the above-mentioned function, and it can be selected according to the purpose. For example, a known developer having a function of attaching a single-component developer or a two-component developer to the electrophotographic photoreceptor 7 using a brush, a roller, etc. can be cited. Among them, for example, a developer using a developing roller that holds the developer on the surface is preferred.

[0448] The developer used in the developing device 11 may be a single-component developer containing only a toner, or a two-component developer containing a toner and a carrier. Furthermore, the developer may be magnetic or non-magnetic. These developers are suitable for known developers.

[0449] -Cleaning device-

[0450] The cleaning device 13 may be a cleaning blade type device including a cleaning blade 131. In addition to the cleaning blade type, a brush cleaning method or a simultaneous development cleaning method may be used.

[0451] -Transfer device-

[0452] Examples of the transfer device 40 include a contact transfer charger using a belt, a roller, a film, a rubber blade, etc.; a corotron transfer charger using corona discharge; a corotron transfer charger, etc., which are known per se.

[0453] -Intermediate transfer body-

[0454] As the intermediate transfer body 50, a belt-shaped transfer body (intermediate transfer belt) made of polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber, etc. imparted with semiconductivity can be used. In addition, as a form of the intermediate transfer body, a roller-shaped transfer body can be used.

[0455] Picture 3 It is a schematic configuration diagram showing another example of the image forming apparatus according to the present embodiment.

[0456] Picture 3 The image forming apparatus 120 shown is a multi-color image forming apparatus of a tandem type equipped with four process cartridges 300. In the image forming apparatus 120, four process cartridges 300 are arranged on the intermediate transfer body 50, respectively, and a single electrophotographic photoreceptor is used for each color. The image forming apparatus 120 has the same structure as the image forming apparatus 100 except for the tandem type.

[0457] Example

[0458] Hereinafter, embodiments of the present invention will be described in detail based on examples, but the embodiments of the present invention are not limited to these examples at all.

[0459] In the following description, "parts" and "%" are based on mass unless otherwise specified.

[0460] In the following description, unless otherwise specified, synthesis, treatment, production, etc. are performed at room temperature (25° C.±3° C.).

[0461] [Synthesis of Resin XA]

[0462] 20 parts by mass of xylene were added to a 200 ml three-necked flask, and heated and stirred at 110° C. Next, a mixed solution 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 type and amount shown in Table 1, 10 parts by mass of butyl acetate, and 1 part by mass of a polymerization catalyst, tert-butyl peroxy-2-ethylhexanoate, was slowly added dropwise at 110° C. over 2 hours under a nitrogen atmosphere. Then, the mixture was reacted at 120° C. for 2 hours to copolymerize and obtain a resin.

[0463] [Synthesis of Resin XB]

[0464] A resin was obtained according to the same specifications as in the synthesis of the resin XA except that the dropping temperature was changed to 120°C.

[0465] [Synthesis of Resin XC]

[0466] A resin was obtained according to the same specifications as in the synthesis of the resin XA except that the dropping temperature was changed to 90°C.

[0467] [Synthesis of Resin XD]

[0468] A resin was obtained with the same specifications as for the synthesis of resin XA, except that 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 of the types and amounts shown in Table 1 and the dropping temperature was changed to 100°C.

[0469] [Synthesis of Resin XE]

[0470] 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 set to the types and amounts shown in Table 1, and the dropping temperature was changed to 80°C. Except for this, a resin was obtained with the same specifications as the synthesis of resin XA.

[0471] [Synthesis of Resin XF]

[0472] 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 set to the types and amounts shown in Table 1, and the dropping temperature was changed to 110° C., and a resin was obtained with the same specifications as the synthesis of resin XA.

[0473] [Synthesis of Resin XG]

[0474] 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 set to the types and amounts shown in Table 1, and the dropping temperature was changed to 105°C. Except for this, a resin was obtained with the same specifications as the synthesis of resin XA.

[0475] [Synthesis of Resin XH]

[0476] 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 set to the types and amounts shown in Table 1, the dropping temperature was changed to 80°C, and the reaction time was changed to 3 hours. Except for this, a resin was obtained with the same specifications as the synthesis of resin XA.

[0477] [Synthesis of Resin XI]

[0478] 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 set to the types and amounts shown in Table 1, the dropping temperature was changed to 75°C, and the reaction time was set to 3.5 hours. Except for this, a resin was obtained with the same specifications as the synthesis of resin XA.

[0479] [Synthesis of Resin XJ]

[0480] 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 set to the types and amounts shown in Table 1, the dropping temperature was changed to 80°C, and the reaction time was changed to 4 hours. Except for this, a resin was obtained with the same specifications as the synthesis of resin XA.

[0481] [Synthesis of Resin XK]

[0482] 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 set to the types and amounts shown in Table 1, and the dropping temperature was changed to 135°C. Except for this, a resin was obtained with the same specifications as the synthesis of resin XA.

[0483] [Synthesis of Resin XL]

[0484] A resin was obtained according to the same specifications as the synthesis of resin XA, except that 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 of the types and amounts shown in Table 1.

[0485] [Synthesis of Resin XM]

[0486] A resin was obtained according to the same specifications as the synthesis of resin XA, except that 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 of the types and amounts shown in Table 1.

[0487] [Synthesis of Resin XN]

[0488] A resin was obtained according to the same specifications as the synthesis of resin XA, except that 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 of the types and amounts shown in Table 1.

[0489] Table 1 shows the weight average molecular weight Mw of each resin determined by the above-mentioned measurement method.

[0490] In Table 1, "-" in the item of each material indicates that the material is not included.

[0491] [Table 1]

[0492]

[0493] <Production of electrophotographic photoreceptors>

[0494] [Example 1]

[0495] As the 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.

[0496] -Formation of lower coating layer-

[0497] Zinc oxide (average particle size 70 nm, specific surface area 15 m 2 / g, manufactured by TAYCA CORPORATION) and 500 parts of toluene were mixed and stirred, and 1.3 parts of a silane coupling agent (trade name: KBM603, manufactured by Shin-Etsu Chemical Co., Ltd., N-2-(aminoethyl)-3-aminopropyltrimethoxysilane) were added and stirred for 2 hours. Then, the toluene was distilled under reduced pressure and sintered at 120° C. for 3 hours to obtain zinc oxide surface-treated with a silane coupling agent.

[0498] 110 parts of surface-treated zinc oxide and 500 parts of tetrahydrofuran were mixed and stirred, and a solution of 0.6 parts of alizarin dissolved in 50 parts of tetrahydrofuran was added, followed by stirring at 50° C. for 5 hours. Then, the solid content was filtered out by vacuum filtration and dried at 60° C. to obtain zinc oxide with alizarin.

[0499] 60 parts of zinc oxide to impart alizarin, 13.5 parts of a curing agent (blocked isocyanate, trade name: SUMIDUR3175, manufactured by Sumitomo Bayer Urethane Co., Ltd.) and 15 parts of a butyral resin (trade name: S-LEC BM-1, manufactured by SEKISUI CHEMICAL CO., LTD.) were dissolved in 100 parts of a solution containing 68 parts of methyl ethyl ketone and 5 parts of methyl ethyl ketone, and the mixture was stirred for 2 hours. The glass beads were dispersed by a sand mill for 2 hours to obtain a dispersion. 0.005 parts of dioctyltin dilaurate and 4 parts of silicone resin particles (trade name: Tospearl145, manufactured by Momentive performance Materials Inc.) were added to the dispersion as a catalyst to obtain a coating solution for forming an undercoat layer. The coating solution for forming an undercoat layer was applied to the outer peripheral surface of the 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.

[0500] -Formation of Charge Generation Layer-

[0501] A mixture consisting 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 a vinyl chloride-vinyl acetate copolymer resin (trade name: VMCH, manufactured by Nippon Unicar Company Limited) as a binder resin, and 200 parts of n-butyl acetate was dispersed using glass beads having a diameter of 1 mm and a sand mill for 4 hours. 175 parts of n-butyl acetate and 180 parts of methyl ethyl ketone were added to the dispersion, and the mixture was stirred to obtain a coating liquid for forming a charge generating layer. The coating liquid 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 having an average thickness of 0.18 μm.

[0502] -Formation of Charge Transport Layer-

[0503] 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 liquid for forming a charge transport layer. The coating liquid for forming a charge transport layer was dip-coated on the charge generating 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 is the thickness shown in Table 2.

[0504] [Chemical formula 37]

[0505]

[0506] -Formation of surface protective layer-

[0507] In a mixed solvent of 30 parts by mass of isopropyl alcohol 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 and dissolved by stirring at 50° C. for 2 hours. Then, after naturally cooling to room temperature (25° C.), 0.1 parts by mass of curing catalyst Nacure 5925 (manufactured by King Industries, Inc.) and 0.08 parts by mass of the resin XA were added to obtain a coating liquid for forming a surface protective layer.

[0508] The coating liquid for forming a surface protective layer was dip-coated on the charge transport layer at a coating speed corresponding to the target film thickness, and dried by finger touch at 25° C. for 10 minutes, and then dried and cured at 150° C. for 40 minutes to obtain the photoreceptor of Example 1. The average film thickness of the surface protective layer was the thickness shown in Table 2.

[0509] [Examples 2 to 7, Examples 9 to 23 and Comparative Examples 1 to 4]

[0510] The film thickness of the surface protection layer, the film thickness of the charge transport layer, and the film thickness T CT (μm) and the film thickness T of the surface protection layer OVC (μm) ratio (T CT / T OVC )(In the table, marked as "ratio (T CT / T OVC The photoreceptors of each example were prepared with the same specifications as those of Example 1 except that the specifications were as shown in Table 2.

[0511] [Example 11]

[0512] In the "Evaluation of Removability" described later, the same specifications as in Example 2 were adopted except that the linear pressure of the primary transfer was set to the range shown in Table 2.

[0513] [Reference Example 1]

[0514] A photoreceptor was prepared in the same specifications as in Example 1 except that resins of the types and mass ratios shown in Table 2 were used instead of the resin (X) in the step of forming the surface protection layer.

[0515] In each table, "mass ratio (mass %) of resin" refers to the mass ratio of the resin (X) in the surface protective layer. In this case, in the comparative example where KP-340 or KP-104 was used instead of the resin (X), KP-340 or KP-104 was regarded as the resin (X) to calculate the "mass ratio (mass %) of resin".

[0516] <Evaluation>

[0517] [Evaluation of streak-like image defects]

[0518] The photosensitive body of each example was installed in an image forming apparatus Color 1000i Press (manufactured by FUJIFILM Business Innovation Corp.), and 50,000 sheets of chart images with an image density (area coverage) of 10% were continuously output on A4-sized plain paper under an environment of a temperature of 30°C and a relative humidity of 85% (high temperature and high humidity). The streak-like image defects were classified into the following A to E by visually observing the 10th image and the 50,000th image. The fewer the streak-like image defects, the fewer the coating defects of the surface protective layer. The results are shown in "Evaluation of streak-like image defects" in Table 2.

[0519] A: There are no streaky image defects and there is no problem with the image quality.

[0520] B: There is a slight streak-like image defect in a partial area of ​​the image, but it is at a level that does not cause a problem in practical use.

[0521] C: There is a noticeable streak-like image defect in a partial area of ​​the image, but it is at a level that does not cause a problem in practical use.

[0522] D: There are streaky image defects in half of the image area, which are not negligible in terms of image quality.

[0523] E: There are streak-like image defects throughout the entire image, which is at a level that causes problems in practical use.

[0524] [Evaluation of peeling]

[0525] The photoreceptors of each example were installed in an image forming device Color 1000i Press (manufactured by FUJIFILM Business Innovation) equipped with an intermediate transfer belt as the first transfer body. Then, 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, and 50,000 chart images with an image density (area coverage) of 10% were continuously output on A4-sized plain paper at a processing speed of 260 mm / sec. Then, the electrophotographic photoreceptor was removed from the image forming device, 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 criteria. The results are shown in "Evaluation of Peeling" in Table 2.

[0526] A: There is no peeling of the surface protection layer from the charge transport layer in the entire area

[0527] B: One or more but less than five peelings are present

[0528] C: There are 6 or more but less than 10 peelings.

[0529] D: There are more than 10 and less than 20 peelings

[0530] E: There are more than 20 peelings

[0531] [Evaluation of image output]

[0532] As an image forming device for storing electrostatic charge image developer, DocuCentre-V C2263 (manufactured by FUJIFILM Business Innovation) was prepared, and the electrophotographic photoreceptor of each example was installed. 500 halftone images (image density 30%) were output on A4-sized plain paper, and the 500th image was evaluated. The evaluation criteria are shown below. The results are shown in "Evaluation of image output" in Table 2.

[0533] A: No problem in mid-tone images

[0534] B: There is a difference in dot size in the mid-tone image (level without a problem)

[0535] C: Dots of mid-tone images are not clear

[0536]

[0537] As shown in the above table, it can be seen that the peeling of the surface protection layer from the charge transport layer is suppressed in the photoreceptor of Example as compared with the photoreceptor of Comparative Example.

[0538] This embodiment includes the following aspects.

[0539] (1) An electrophotographic photoreceptor comprising:

[0540] Conductive substrate;

[0541] A charge generating layer is disposed on the conductive substrate;

[0542] a charge transport layer disposed on the charge generation layer; and

[0543] A surface protection layer is disposed on the charge transport layer,

[0544] The charge transport layer has a thickness of 8 μm or more and 25 μm or less.

[0545] The surface protective layer is a cured film having a film thickness of 10 μm or less and comprising a composition of 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.

[0546] [Chemical formula 38]

[0547] Formula (X1)

[0548] Formula (X2)

[0549] 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 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof, 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, and 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 ), 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.

[0550] 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 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof, 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, and R 204 It is an alkyl group having 6 to 30 carbon atoms.

[0551] (2) The electrophotographic photoreceptor according to (1), wherein

[0552] The film thickness T of the charge transport layer CT (μm) and the film thickness T of the surface protection layer OVC (μm) ratio (T CT / T OVC ) is greater than 1.42 and less than 25.

[0553] (3) The electrophotographic photoreceptor according to (1), wherein

[0554] The charge transport layer has a film thickness of 8 μm or more and 20 μm or less.

[0555] (4) The electrophotographic photoreceptor according to (3), wherein

[0556] The charge transport layer has a film thickness of 9 μm or more and 20 μm or less.

[0557] (5) The electrophotographic photoreceptor according to (1), wherein

[0558] The surface protection layer has a film thickness of 1 μm or more and 10 μm or less.

[0559] (6) The electrophotographic photoreceptor according to (5), wherein

[0560] The surface protection layer has a film thickness of 5 μm or more and 9 μm or less.

[0561] (7) A process cartridge comprising the electrophotographic photoreceptor according to any one of (1) to (6), wherein:

[0562] The process cartridge is attachable to and detachable from the image forming apparatus.

[0563] (8) An image forming apparatus comprising:

[0564] The electrophotographic photoreceptor according to any one of (1) to (6);

[0565] A charging device for charging the surface of the electrophotographic photoreceptor;

[0566] An electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the electrophotographic photoreceptor;

[0567] a developing device for developing the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image; and

[0568] The transfer device transfers the toner image to the surface of a recording medium.

[0569] (9) The image forming apparatus according to (8), wherein:

[0570] The transfer device comprises:

[0571] Intermediate transfer belt;

[0572] a scraper contacting with the outer peripheral surface of the intermediate transfer belt and cleaning the outer peripheral surface;

[0573] a primary transfer device having a primary transfer member for primary transferring a toner image formed on a surface of an image holding member to an outer peripheral surface of the intermediate transfer belt at a transfer pressure of 17 g / cm or less; and

[0574] The secondary transfer device includes a secondary transfer member arranged in contact with the outer peripheral surface of the intermediate transfer belt and secondarily transferring the toner image transferred to the outer peripheral surface of the intermediate transfer belt to a surface of a recording medium.

[0575] According to the invention of (1), there is provided an electrophotographic photoreceptor in which peeling of the surface protective layer from the charge transport layer is suppressed compared with a case where the film thickness of the charge transport layer exceeds 25 μm or a case where the film thickness of the surface protective layer exceeds 10 μm.

[0576] According to the invention described in (2), there is provided a charge transport layer having a film thickness T CT (μm) and the film thickness T of the surface protection layer OVC (μm) ratio (T CT / T OVC ) exceeds 25, the electrophotographic photoreceptor in which the peeling of the surface protective layer from the charge transport layer is suppressed.

[0577] According to the invention as set forth in (3), there is provided an electrophotographic photoreceptor in which the peeling of the surface protective layer from the charge transport layer is suppressed compared with a case where the film thickness of the charge transport layer is less than 8 μm or exceeds 20 μm.

[0578] According to the invention as set forth in (4), there is provided an electrophotographic photoreceptor in which separation of the surface protective layer from the charge transport layer is suppressed compared with a case where the film thickness of the charge transport layer is less than 9 μm or exceeds 20 μm.

[0579] According to the invention as set forth in (5), there is provided an electrophotographic photoreceptor in which separation of the surface protective layer from the charge transport layer is suppressed compared with a case where the film thickness of the surface protective layer is less than 1 μm or exceeds 10 μm.

[0580] According to the invention as set forth in (6), there is provided an electrophotographic photoreceptor in which separation of the surface protective layer from the charge transport layer is suppressed compared with a case where the film thickness of the surface protective layer is less than 5 μm or exceeds 9 μm.

[0581] According to the invention involved in (7) or (8), there is provided a processing box or image forming device having the following electrophotographic photosensitive body, that is, an electrophotographic photosensitive body in which the peeling of the surface protective layer from the charge transport layer is suppressed compared with the case where the film thickness of the charge transport layer exceeds 25 μm or the case where the film thickness of the surface protective layer exceeds 10 μm.

[0582] According to the invention involved in (9), there is provided an image forming device comprising an electronic photographic photosensitive body, i.e., an electronic photographic photosensitive body in which peeling of a surface protective layer from a charge transport layer is suppressed, compared with a case in which a transfer device comprises an intermediate transfer belt, a scraper which contacts with the outer peripheral surface of the intermediate transfer belt and cleans the outer peripheral surface, a primary transfer device having a primary transfer component which transfers a toner image formed on the surface of an image retaining body to the outer peripheral surface of the intermediate transfer belt at a transfer pressure exceeding 17 g / cm, and a secondary transfer device having a secondary transfer component which is arranged in contact with the outer peripheral surface of the intermediate transfer belt and transfers the toner image transferred to the outer peripheral surface of the intermediate transfer belt to the surface of a recording medium for a second time.

[0583] The above-mentioned embodiments of the present invention are provided for the purpose of illustration and description. In addition, the embodiments of the present invention do not fully and exhaustively include the present invention, and do not limit the present invention to the disclosed methods. Obviously, various modifications and changes are self-evident to those skilled in the art to which the present invention belongs. The present embodiment is selected and described in order to most easily understand the principles of the present invention and its application. Thus, other technicians in the art can understand the present invention through various variations optimized for specific uses assumed to be various embodiments. The scope of the present invention is defined by the above claims and their equivalents.

Claims

1. An electrophotographic photoreceptor, comprising: Conductive substrate; A charge generating layer is disposed on the conductive substrate; a charge transport layer disposed on the charge generation layer; and A surface protection layer is disposed on the charge transport layer, The charge transport layer has a thickness of 8 μm or more and 25 μm or less. The surface protection layer is a cured film having a thickness of 10 μm or less and comprising a composition of 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, [Chemical formula 1] 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 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof, 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, and 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 ), R 109 , R 110 , R 111 , R 112 and R 113 are each independently an alkyl group having 1 to 5 carbon atoms, 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 is a single bond, an alkylene group having 1 to 5 carbon atoms, -O-, -C(=O)-, -C(=O)O-, an aromatic ring which may have a substituent, or a combination thereof, 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, and R 204 It is an alkyl group having 6 to 30 carbon atoms.

2. The electrophotographic photoreceptor according to claim 1, wherein The film thickness T of the charge transport layer CT (μm) and the film thickness T of the surface protection layer OVC (μm) ratio (T CT / T OVC ) is greater than 1.42 and less than 25.

3. The electrophotographic photoreceptor according to claim 1, wherein The charge transport layer has a film thickness of 8 μm or more and 20 μm or less.

4. The electrophotographic photoreceptor according to claim 3, wherein The charge transport layer has a film thickness of 9 μm or more and 20 μm or less.

5. The electrophotographic photoreceptor according to claim 1, wherein The surface protection layer has a film thickness of 1 μm or more and 10 μm or less.

6. The electrophotographic photoreceptor according to claim 5, wherein The surface protection layer has a film thickness of 5 μm or more and 9 μm or less.

7. A process cartridge comprising the electrophotographic photoreceptor according to any one of claims 1 to 6, wherein: The process cartridge is attachable to and detachable from the image forming apparatus.

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

9. The image forming apparatus according to claim 8, wherein: The transfer device comprises: Intermediate transfer belt; a scraper contacting with the outer peripheral surface of the intermediate transfer belt and cleaning the outer peripheral surface; a primary transfer device having a primary transfer member for primary transferring a toner image formed on a surface of an image holding member to an outer peripheral surface of the intermediate transfer belt at a transfer pressure of 17 g / cm or less; and The secondary transfer device includes a secondary transfer member arranged in contact with the outer peripheral surface of the intermediate transfer belt and secondarily transferring the toner image transferred to the outer peripheral surface of the intermediate transfer belt to a surface of a recording medium.

Images