Electrophotographic photoreceptor, process cartridge, and image forming device

Abstract

An electronic photographic photoreceptor, a processing box and an image forming device, wherein the electronic photographic photoreceptor comprises: a conductive substrate, an undercoat layer arranged on the conductive substrate, and a photosensitive layer arranged on the undercoat layer, wherein the undercoat layer contains at least one pyrone compound and polyurethane selected from the group consisting of compounds represented by formula (1) and compounds represented by formula (2) shown below, or contains at least one pyrone compound selected from the group consisting of compounds represented by formulas (1) and (2) and at least one acceptor compound selected from the group consisting of compounds represented by formulas (3) to (15) shown in the specification, or contains a resin obtained by polymerizing a diallyl phthalate compound and a charge transport material.

Description

Technical Field

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

[0002] In the related art, as an electrophotographic image forming apparatus, an apparatus that sequentially performs steps such as charging, forming an electrostatic latent image, developing, transferring, and cleaning using an electrophotographic photoreceptor is widely known.

[0003] As electronic photographic photoreceptors, there are known functional separation type photoreceptors (in which a charge generating layer for generating charges and a charge transporting layer for transporting charges are stacked on a conductive substrate such as aluminum) or single layer type photoreceptors (in which a single layer performs both the function of generating charges and the function of transporting charges).

[0004] Patent Document 1 discloses an electrophotographic photoreceptor in which an intermediate layer and a photosensitive layer are sequentially provided on a conductive support and the intermediate layer contains a polyolefin resin and a benzimidazole compound.

[0005] Patent Document 2 discloses an electrophotographic photoreceptor including an intermediate layer and a photosensitive layer in this order on a support, wherein the intermediate layer contains an electron transporting substance selected from the group consisting of a naphthalene amidine imide compound, a perylene amidine imide compound and an imide resin.

[0006] Patent Document 3 discloses an electrophotographic photoreceptor including an intermediate layer and a photosensitive layer in this order on a support, wherein the intermediate layer contains an electron transporting substance selected from the group consisting of naphthalene amidine imide compounds and perylene amidine imide compounds.

[0007] Patent Document 4 discloses a benzimidazole compound as an electron transporting substance used in an undercoat layer of an electrophotographic photoreceptor.

[0008] Patent Document 5 discloses an electrophotographic photoreceptor comprising a support, an undercoat layer and a photosensitive layer, wherein the undercoat layer comprises metal oxide particles surface-treated with a silane coupling agent, a binder resin and an organic acid salt of a metal selected from bismuth, zinc, cobalt, iron, nickel and copper.

[0009] Patent Document 6 discloses an electrophotographic photoreceptor comprising at least an undercoat layer and a photosensitive layer on a conductive substrate, wherein the undercoat layer comprises metal oxide fine particles to which at least one acceptor compound selected from hydroxyanthraquinone compounds and aminohydroxyanthraquinone compounds is attached.

[0010] In addition, Patent Document 1 discloses an electronic photographic photoreceptor, wherein an intermediate layer and a photosensitive layer are sequentially arranged on a conductive support, the intermediate layer contains a polyolefin resin and an organic electron transporting substance, and the organic electron transporting substance is a compound selected from the group consisting of imide compounds, benzimidazole compounds, quinone compounds, cyclopentadienyl compounds, azo compounds and their derivatives.

[0011] Patent Document 7 discloses an electrophotographic photoreceptor in which an undercoat layer and a protective layer are sequentially provided on a conductive support, the undercoat layer comprising an olefin resin and an organic electron transport material, the olefin resin containing as a constituent a compound having at least one of a carboxylic acid group and a carboxylic anhydride group.

[0012] [Patent Document 1] JP-A-2011-095665

[0013] [Patent Document 2] Japanese Patent Publication No. 3958154

[0014] [Patent Document 3] Japanese Patent Publication No. 3958155

[0015] [Patent Document 4] JP-A-2015-026067

[0016] [Patent Document 5] JP-A-2014-186296

[0017] [Patent Document 6] Japanese Patent No. 4456955

[0018] [Patent Document 7] JP-A-2009-288621 Summary of the invention

[0019] A first object of the present invention is to provide an electrophotographic photoreceptor (first electrophotographic photoreceptor) having excellent charge retention properties compared with a case where an undercoat layer contains a perinone compound and polyamide or polycarbonate but does not contain polyurethane.

[0020] A second object of the present invention is to provide an electronic photographic photoreceptor (a second electronic photographic photoreceptor) that can prevent deterioration of photosensitivity during repeated image formation compared to a case where the undercoat layer contains at least one of the compounds represented by the formula (1) or (2) described later and only the compound (18-1) or (18-2) described later as an acceptor compound.

[0021] In addition, when an image is repeatedly formed using an electrophotographic photoreceptor including an undercoat layer, there are some cases where a residual potential rise is caused. Therefore, a third object of the present invention is to provide an electrophotographic photoreceptor (third electrophotographic photoreceptor) that can prevent a residual potential from rising when repeated images are formed, compared with a case where the electrophotographic photoreceptor includes a conductive substrate, a photosensitive layer provided on the conductive substrate, wherein the undercoat layer is provided between the conductive substrate and the photosensitive layer and contains a charge transport material and a binder resin containing only a polyamide resin.

[0022] The first object is achieved by any one of the following first to seventh aspects.

[0023] According to a first aspect of the present invention, there is provided an electrophotographic photoreceptor comprising:

[0024] Conductive substrate;

[0025] a primer layer disposed on the conductive substrate; and

[0026] A photosensitive layer is provided on the base coating layer,

[0027] The primer layer contains at least one pyrenone compound and polyurethane selected from the group consisting of compounds represented by formula (1) and compounds represented by formula (2) shown below.

[0028]

[0029] In formula (1), R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 Each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom, and R 11 and R 12 Can be connected to each other to form a ring, R 12 and R 13 Can be connected to each other to form a ring, R 13 and R 14 Can be connected to each other to form a ring, R 15 and R 16 Can be connected to each other to form a ring, R 16 and R 17 can be connected to each other to form a ring, and R 17 and R 18 Can be connected to each other to form a ring.

[0030] In formula (2), R21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 and R 28 Each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom, and R 21 and R 22 Can be connected to each other to form a ring, R 22 and R 23 Can be connected to each other to form a ring, R 23 and R 24 Can be connected to each other to form a ring, R 25 and R 26 Can be connected to each other to form a ring, R 26 and R 27 can be connected to each other to form a ring, and R 27 and R 28 Can be connected to each other to form a ring.

[0031] According to a second aspect of the invention, in the electrophotographic photoreceptor of the first aspect, the undercoat layer further contains at least one of an organic acid metal salt and a metal organic complex each containing a metal selected from the group consisting of bismuth, aluminum, zirconium, zinc, cobalt, iron, nickel and copper.

[0032] According to a third aspect of the present invention, in the electrophotographic photoreceptor of the second aspect, the total content of the organic acid metal salt and the metal organic complex is 0.001 wt % to 3 wt % based on the total solid content of the undercoat layer.

[0033] According to a fourth aspect of the present invention, in the electrophotographic photoreceptor of the first aspect, the total content of the pyrenone compound is 30% by weight or more relative to the total solid content of the undercoat layer.

[0034] According to a fifth aspect of the present invention, in the electrophotographic photoreceptor of the first aspect, the undercoat layer further contains at least one metal oxide particle selected from the group consisting of zinc oxide particles, titanium oxide particles, and tin oxide particles.

[0035] According to a sixth aspect of the present invention, there is provided a process cartridge that can be attached and detached from an image forming apparatus, the process cartridge comprising:

[0036] The electrophotographic photoreceptor according to any one of the first to fifth aspects.

[0037] According to a seventh aspect of the present invention, there is provided an image forming apparatus comprising:

[0038] The electrophotographic photoreceptor according to any one of the first to fifth aspects;

[0039] a charging unit that charges the surface of the electrophotographic photoreceptor;

[0040] an electrostatic latent image forming unit that forms an electrostatic latent image on the charged surface of the electrophotographic photoreceptor;

[0041] a developing unit that develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image; and

[0042] A transfer unit transfers the toner image onto a surface of a recording medium.

[0043] The second object is achieved by any one of the following eighth to thirteenth aspects.

[0044] According to an eighth aspect of the present invention, there is provided an electrophotographic photoreceptor comprising:

[0045] Conductive substrate;

[0046] a primer layer disposed on the conductive substrate; and

[0047] A photosensitive layer is provided on the base coating layer,

[0048] The primer layer contains at least one pyrone compound selected from the group consisting of compounds represented by formula (1) and compounds represented by formula (2) described later, and at least one receptor compound selected from the group consisting of compounds represented by formula (3), compounds represented by formula (4), compounds represented by formula (5), compounds represented by formula (6), compounds represented by formula (7), compounds represented by formula (8), compounds represented by formula (9), compounds represented by formula (10), compounds represented by formula (11), compounds represented by formula (12), compounds represented by formula (13), compounds represented by formula (14) and compounds represented by formula (15).

[0049] According to a ninth aspect of the present invention, in the electrophotographic photoreceptor of the eighth aspect, the total content of the acceptor compound is 2% by weight to 30% by weight relative to the total content of the pyrenone compound contained in the undercoat layer.

[0050] According to a tenth aspect of the present invention, in the electrophotographic photoreceptor of the eighth aspect, the total content of the pyrenone compound is 50 wt % to 90 wt % based on the total solid content of the undercoat layer.

[0051] According to the eleventh aspect of the present invention, in the electronic photographic photosensitive body of the eighth aspect, the acceptor compound comprises at least one acceptor compound selected from the group consisting of a compound represented by formula (6), a compound represented by formula (13), a compound represented by formula (14) and a compound represented by formula (15).

[0052] According to a twelfth aspect of the present invention, there is provided a process cartridge that can be attached and detached from an image forming apparatus, the process cartridge comprising:

[0053] The electrophotographic photoreceptor according to any one of the eighth to eleventh aspects.

[0054] According to a thirteenth aspect of the present invention, there is provided an image forming apparatus comprising:

[0055] The electrophotographic photoreceptor according to any one of the eighth to eleventh aspects;

[0056] a charging unit that charges the surface of the electrophotographic photoreceptor;

[0057] an electrostatic latent image forming unit that forms an electrostatic latent image on the charged surface of the electrophotographic photoreceptor;

[0058] a developing unit that develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image; and

[0059] A transfer unit transfers the toner image onto a surface of a recording medium.

[0060] The third object is achieved by any one of the following fourteenth to twenty-third aspects.

[0061] According to a fourteenth aspect of the present invention, there is provided an electrophotographic photoreceptor comprising:

[0062] Conductive substrate;

[0063] an undercoat layer provided on the conductive substrate and containing a binder resin and a charge transporting material, the binder resin containing a resin obtained by polymerizing a diallyl phthalate compound; and

[0064] A photosensitive layer is disposed on the undercoat layer.

[0065] According to a fifteenth aspect of the present invention, in the electrophotographic photoreceptor of the fourteenth aspect, the diallyl phthalate compound contains a diallyl isophthalate compound.

[0066] According to a sixteenth aspect of the present invention, in the electrophotographic photoreceptor of the fourteenth aspect, the diallyl phthalate compound contains a monomer and a prepolymer of the diallyl phthalate compound.

[0067] According to a seventeenth aspect of the present invention, in the electrophotographic photoreceptor of the sixteenth aspect, a weight ratio of the monomer to the prepolymer is 1 / 99 to 99 / 1.

[0068] According to an eighteenth aspect of the present invention, in the electrophotographic photoreceptor of the fourteenth aspect, the charge transport material contains at least one pyrenone compound represented by formula (1) or (2).

[0069]

[0070] (In formula (1), R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 Each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom, and R 11 and R 12 Can be connected to each other to form a ring, R 12 and R 13 Can be connected to each other to form a ring, R 13 and R 14 Can be connected to each other to form a ring, R 15 and R 16 Can be connected to each other to form a ring, R 16 and R 17 can be connected to each other to form a ring, and R 17 and R 18 Can be connected to each other to form a ring.

[0071] In formula (2), R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 and R 28 Each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom, and R 21 and R 22 Can be connected to each other to form a ring, R 22 and R 23Can be connected to each other to form a ring, R 23 and R 24 Can be connected to each other to form a ring, R 25 and R 26 Can be connected to each other to form a ring, R 26 and R 27 can be connected to each other to form a ring, and R 27 and R 28 Can be connected to each other to form a ring.)

[0072] According to a nineteenth aspect of the present invention, in the electrophotographic photoreceptor of the eighteenth aspect, R in the formula (1) 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 Each independently represents a hydrogen atom, an alkyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group or an aryloxycarbonylalkyl group, and R in formula (2) 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 and R 28 Each independently represents a hydrogen atom, an alkyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group or an aryloxycarbonylalkyl group.

[0073] According to a twentieth aspect of the present invention, in the electrophotographic photoreceptor of the fourteenth aspect, the binder resin includes a resin obtained by polymerizing the diallyl phthalate compound and a (meth)acrylic monomer.

[0074] According to a twenty-first aspect of the present invention, in the electrophotographic photoreceptor of the fourteenth aspect, the content of the charge transport material is 40% by weight to 80% by weight relative to the total solid content of the undercoat layer.

[0075] According to a twenty-second aspect of the present invention, there is provided a process cartridge that can be attached and detached from an image forming apparatus, the process cartridge comprising:

[0076] The electrophotographic photoreceptor according to any one of the fourteenth to twenty-first aspects.

[0077] According to a twenty-third aspect of the present invention, there is provided an image forming apparatus comprising:

[0078] The electrophotographic photoreceptor according to any one of the fourteenth to twenty-first aspects;

[0079] a charging unit that charges the surface of the electrophotographic photoreceptor;

[0080] an electrostatic latent image forming unit that forms an electrostatic latent image on the charged surface of the electrophotographic photoreceptor;

[0081] a developing unit that develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image; and

[0082] A transfer unit transfers the toner image onto a surface of a recording medium.

[0083] According to the invention described in claim 1 or 4, there is provided an electrophotographic photoreceptor having excellent charge retention characteristics compared with a case where the undercoat layer contains a pyrenone compound and polyamide or polycarbonate but does not contain polyurethane.

[0084] According to the invention described in claim 2, there is provided an electrophotographic photoreceptor which can excellently prevent an increase in residual potential when repeatedly forming images, compared with a case where the undercoat layer does not contain an organic acid metal salt and a metal organic complex.

[0085] According to the invention described in claim 3, there is provided an electrophotographic photoreceptor which can excellently prevent an increase in residual potential during repeated use compared with a case where the total content of the organic acid metal salt and the metal organic complex contained in the undercoat layer is less than 0.001 wt %.

[0086] According to the invention described in claim 5, there is provided an electrophotographic photoreceptor which can prevent leakage due to adhesion of foreign matter to the photoreceptor compared with the case where no metal oxide particles are contained.

[0087] According to the invention described in claim 6, there is provided a process cartridge including an electrophotographic photoreceptor having a charge retention property excellent in comparison with a case where the undercoat layer of the electrophotographic photoreceptor contains a pyrenone compound and polyamide or polycarbonate but does not contain polyurethane.

[0088] According to the invention described in claim 7, there is provided an image forming apparatus including an electrophotographic photoreceptor having excellent charge retention characteristics compared with a case where the undercoat layer of the electrophotographic photoreceptor contains a pyrenone compound and polyamide or polycarbonate but does not contain polyurethane.

[0089] According to the invention described in the eighth, tenth or eleventh aspect, there is provided an electronic photographic photosensitive body which can prevent the deterioration of photosensitivity during repeated image formation compared to the case where the undercoat layer contains at least one of the compounds represented by formulas (1) and (2) and only the later-described compound (18-1) or (18-2) as an acceptor compound.

[0090] According to the invention described in the ninth aspect, an electronic photographic photoreceptor is provided that can prevent deterioration of photosensitivity during repeated image formation compared to the case where the total content of the acceptor compound is less than 5 weight % or greater than 30 weight % relative to the total content of the pyrone compound contained in the undercoat layer.

[0091] According to the invention described in the twelfth aspect, there is provided a processing box that can prevent the deterioration of photosensitivity during repeated image formation compared to a case where the base coating layer of the electronic photographic photosensitive body contains at least one of the compounds represented by formulas (1) and (2) and only the later-described compound (18-1) or (18-2) as an acceptor compound.

[0092] According to the invention described in the thirteenth aspect, there is provided an image forming device which can prevent the deterioration of photosensitivity during repeated image formation, compared with a case where the base coating layer of the electronic photographic photosensitive body contains at least one of the compounds represented by formulas (1) and (2) and only the later-described compound (18-1) or (18-2) as an acceptor compound.

[0093] According to the invention described in the fourteenth aspect, there is provided an electronic photographic photoreceptor which can prevent the residual potential from rising when forming repeated images compared to a case where the electronic photographic photoreceptor includes a conductive substrate, a photosensitive layer arranged on the conductive substrate, wherein a primer layer is arranged between the conductive substrate and the photosensitive layer and contains a charge transport material and a binder resin comprising only a polyamide resin.

[0094] According to the invention as recited in claim 15, there is provided an electrophotographic photoreceptor capable of preventing an increase in residual potential when repeated images are formed, compared with the case where the diallyl phthalate compound is an orthophthalate compound.

[0095] According to the invention described in claim 16, there is provided an electrophotographic photoreceptor capable of preventing an increase in residual potential when repeated images are formed, compared with a case where the diallyl phthalate compound contains only a prepolymer.

[0096] According to the invention as recited in claim 17, there is provided an electrophotographic photoreceptor capable of preventing an increase in residual potential when repeated images are formed, compared with a case where the weight ratio of the monomer to the prepolymer is less than 1 / 99 or greater than 99 / 1.

[0097] According to the invention as recited in claim 18 or 19, there is provided an electrophotographic photoreceptor capable of preventing an increase in residual potential when repeated images are formed, compared with a case where the charge transport material contains only a charge transport material other than a pyrenone compound.

[0098] According to the invention as recited in claim 20, there is provided an electrophotographic photoreceptor capable of preventing leakage current compared with the case where the binder resin is obtained by polymerizing only a diallyl phthalate compound.

[0099] According to the invention described in claim 21, there is provided an electrophotographic photoreceptor which can prevent the residual potential from rising when repeated images are formed, compared with the case where the content of the charge transport material relative to the total solid content of the undercoat layer is less than 40 wt % or more than 80 wt %.

[0100] According to the invention described in aspect twenty-second or twenty-third, there is provided a processing box or image forming device that can prevent the residual potential from rising when forming repeated images compared to a case where the processing box includes an electronic photographic photoreceptor, the electronic photographic photoreceptor includes a conductive substrate, a photosensitive layer arranged on the conductive substrate, wherein a primer layer is arranged between the conductive substrate and the photosensitive layer and contains a charge transport material and a phenolic resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0101] Exemplary embodiments of the present invention will be described in detail based on the following drawings, in which:

[0102] Figure 1 is a schematic partial cross-sectional view illustrating an example of a layer configuration of an electrophotographic photoreceptor according to an exemplary embodiment;

[0103] Figure 2 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the exemplary embodiment;

[0104] Figure 3 is a schematic configuration diagram illustrating another example of the image forming apparatus according to the exemplary embodiment. DETAILED DESCRIPTION

[0105] Hereinafter, exemplary embodiments of the present disclosure will be described. These descriptions and examples are used to illustrate the exemplary embodiments, but are not intended to limit the scope of the exemplary embodiments.

[0106] In the present disclosure, a numerical range indicated by "to" means a range including the numerical values ​​described before and after "to" as a minimum value and a maximum value, respectively.

[0107] In the numerical ranges described in the multiple stages of the present disclosure, the upper limit or lower limit described in one numerical range can be replaced by the upper limit or lower limit of the numerical range described in another stage. In addition, in the numerical ranges described in the present disclosure, the upper limit or lower limit of the numerical range can be replaced by the value shown in the embodiments.

[0108] In the present disclosure, the term “step” includes not only an independent step but also a case where it is not clearly distinguished from other steps as long as the intended purpose of the step is achieved.

[0109] In the present disclosure, each component may include multiple applicable substances. In the present disclosure, when referring to the amount of each component in the composition, in the case where there are multiple substances corresponding to each component in the composition, unless otherwise specified, the amount of each component refers to the total amount of the multiple substances.

[0110] In the present disclosure, the main component refers to the dominant component. The main component refers to the component that accounts for more than 30% by weight of the total weight of the mixture in a mixture of multiple components.

[0111] In the present disclosure, the electrophotographic photoreceptor is simply referred to as a photoreceptor.

[0112] <First Electrophotographic Photoreceptor>

[0113] The first photoreceptor of the exemplary embodiment includes a conductive substrate, a primer layer disposed on the conductive substrate, and a photosensitive layer disposed on the primer layer, wherein the primer layer contains at least one pyrenone compound and polyurethane selected from the group consisting of the compound represented by formula (1) and the compound represented by formula (2).

[0114] In the present disclosure, the compound represented by formula (1) is also referred to as a pyrone compound (1), and the compound represented by formula (2) is also referred to as a pyrone compound (2).

[0115] Since the first photoreceptor contains at least one of the pyrenone compound (1) and the pyrenone compound (2) and polyurethane, the charge retention property thereof is excellent. The reason is presumed to be the following mechanism.

[0116] For example, compared with a photoreceptor including an undercoat layer containing an imide compound (A), an imide compound (B) or an imide compound (C) described later as a main electron transport material, a photoreceptor including an undercoat layer containing at least one of a pyrone compound (1) and a pyrone compound (2) as a main electron transport material has excellent electrical properties and leakage resistance. However, when at least one of the pyrone compound (1) and the pyrone compound (2) is used as the main electron transport material of the undercoat layer, the charge retention property is insufficient. As a mechanism for insufficient charge retention property, it is believed that due to low hole blocking properties during charging, hole diffusion migration occurs from the pyrone compound (1) or the pyrone compound (2) contained in the undercoat layer to the charge generating material (e.g., phthalocyanine pigment) contained in the photosensitive layer, and ultimately the potential on the surface of the photoreceptor decays.

[0117] In contrast, when polyurethane is used as a binder resin together with at least one of the pyrone compound (1) and the pyrone compound (2), the charge retention property of the photoreceptor is excellent compared to the case where other types of binder resins are used. As a mechanism thereof, it is considered that since polyurethane has a high effect of preventing (barrier effect) the internal charge (dark carrier) of the pyrone compound (1) or the pyrone compound (2) contained in the undercoat layer from being injected into the charge generating material, the potential on the surface of the photoreceptor is not easily attenuated.

[0118] <Second Electrophotographic Photoreceptor>

[0119] The second photoreceptor of the exemplary embodiment includes a conductive substrate, an undercoat layer provided on the conductive substrate, and a photosensitive layer provided on the undercoat layer, wherein the undercoat layer contains at least one pyrone compound selected from the group consisting of compounds represented by formula (1) and compounds represented by formula (2) described later, and at least one receptor compound selected from the group consisting of compounds represented by formula (3), compounds represented by formula (4), compounds represented by formula (5), compounds represented by formula (6), compounds represented by formula (7), compounds represented by formula (8), compounds represented by formula (9), compounds represented by formula (10), compounds represented by formula (11), compounds represented by formula (12), compounds represented by formula (13), compounds represented by formula (14), and compounds represented by formula (15).

[0120] In the present disclosure, the compound represented by formula (1) is also referred to as a pyrone compound (1), and the compound represented by formula (2) is also referred to as a pyrone compound (2).

[0121] In a photoreceptor containing at least any one of the pyrenone compound (1) and the pyrenone compound (2), although the detailed mechanism is unknown, there are cases where the photosensitivity deteriorates when images are repeatedly formed.

[0122] As a result of research conducted by the present inventors, it was found that in a photosensitive body comprising a base coating layer containing at least any one of the pyrone compound (1) and the pyrone compound (2) and at least one receptor compound selected from the compound represented by any one of the formulae (3) to (15), the photosensitivity is not easily deteriorated even when images are repeatedly formed.

[0123] In addition, it was found that in a photosensitive body comprising a base coating layer containing at least one of the pyrone compound (1) and the pyrone compound (2) and at least one acceptor compound selected from the compounds represented by any one of the formulae (3) to (15), the residual potential is not likely to increase even when images are repeatedly formed.

[0124] -Third Electrophotographic Photoreceptor-

[0125] The third electrophotographic photoreceptor according to the exemplary embodiment includes a conductive substrate, an undercoat layer provided on the conductive substrate and containing a binder resin (containing a resin obtained by polymerizing a diallyl phthalate compound) and a charge transporting material, and a photosensitive layer provided on the undercoat layer.

[0126] In the related art, when an electrophotographic photoreceptor including a conductive substrate, a photosensitive layer provided on the conductive substrate, and an undercoat layer provided between the conductive substrate and the photosensitive layer and containing a charge transport material and a binder resin containing only a polyamide resin is used, residual potential may increase when repeated images are formed.

[0127] On the other hand, since the third electrophotographic photoreceptor has the above-mentioned structure, the residual potential can be prevented from increasing when repeated images are formed. The factor that prevents the residual potential from increasing is unknown, but it is considered to be as follows.

[0128] The third electrophotographic photoreceptor contains a resin obtained by polymerizing a diallyl phthalate compound in the undercoat layer. The diallyl phthalate compound is in a liquid state and does not require a solvent when polymerizing. In addition, since the polymerization reaction of the diallyl phthalate compound is a free radical polymerization reaction, water and the like are not produced in the polymerization reaction system. Therefore, when a liquid of the diallyl phthalate compound dispersed with a charge transport material is used as a binder resin through a polymerization reaction, an undercoat layer is formed without removing solvents and by-products by heating or the like. As a result, the dispersibility of the charge transport material in the undercoat layer tends to increase. It is believed that when the dispersibility of the charge transport material in the undercoat layer is high, it is easy to prevent the charge transport property in the undercoat layer from being locally deteriorated, and to prevent the residual potential from rising, even when forming repeated images.

[0129] Hereinafter, first to third photoreceptors according to the exemplary embodiment will be described with reference to the drawings.

[0130] Figure 1 An example of the layer configuration of the photoreceptor according to the exemplary embodiment is schematically shown. Figure 1 The photoreceptor 7A shown has a structure in which an undercoat layer 1, a charge generating layer 2, and a charge transporting layer 3 are sequentially stacked on a conductive substrate 4. The charge generating layer 2 and the charge transporting layer 3 form a photosensitive layer 5. The photoreceptor 7A may have a layer structure in which a protective layer is further provided on the charge transporting layer 3.

[0131] The photoreceptor of the exemplary embodiment may be a functional separation type, in which the charge generating layer 2 and the charge transporting layer 3 are as follows: Figure 1 The photosensitive layer may be a single-layered photosensitive layer such as the photosensitive body 7A shown in the figure, or may be a single-layered photosensitive layer in which the charge generating layer 2 and the charge transporting layer 3 are integrated.

[0132] Hereinafter, the undercoat layer of the first photoreceptor will be described in detail.

[0133] [Base coating]

[0134] The primer layer contains at least one selected from the group consisting of the pyrenone compound (1) and the pyrenone compound (2) and polyurethane. The primer layer may contain inorganic particles and other additives.

[0135] -Perylene ketone compound (1) and perylene ketone compound (2)-

[0136] The primer layer contains at least one selected from the group consisting of a pyrone compound (1) and a pyrone compound (2) and polyurethane. The pyrone compound (1) is a compound represented by the following formula (1). The pyrone compound (2) is a compound represented by the following formula (2).

[0137]

[0138] In formula (1), R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 Each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom. 11 and R 12 Can be connected to each other to form a ring, R 12 and R 13 Can be connected to each other to form a ring, R 13 and R 14 Can be connected to each other to form a ring. 15 and R 16 Can be connected to each other to form a ring, R 16 and R 17 can be connected to each other to form a ring, and R 17 and R 18 Can be connected to each other to form a ring.

[0139] In formula (2), R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 and R 28 Each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom.21 and R 22 Can be connected to each other to form a ring, R 22 and R 23 Can be connected to each other to form a ring, R 23 and R 24 Can be connected to each other to form a ring. 25 and R 26 Can be connected to each other to form a ring, R 26 and R 27 can be connected to each other to form a ring, and R 27 and R 28 Can be connected to each other to form a ring.

[0140] R in formula (1) 11 ~R 18 Examples of the alkyl group represented include alkyl groups having a substituent or an unsubstituted group.

[0141] In formula (1), R 11 ~R 18 Examples of the unsubstituted alkyl group represented include a straight chain alkyl group having 1 to 20 carbon atoms (preferably having 1 to 10 carbon atoms and more preferably having 1 to 6 carbon atoms), a branched alkyl group having 3 to 20 carbon atoms (preferably having 3 to 10 carbon atoms) and a cycloalkyl group having 3 to 20 carbon atoms (preferably having 3 to 10 carbon atoms).

[0142] Examples of the straight-chain alkyl group having 1 to 20 carbon atoms include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, tridecyl, n-tetradecyl, n-pentadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl and n-eicosyl.

[0143] Examples of the branched alkyl group having 3 to 20 carbon atoms include isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, isohexyl, sec-hexyl, tert-hexyl, isoheptyl, sec-heptyl, tert-heptyl, isooctyl, sec-octyl, tert-octyl, isononyl, sec-nonyl, tert-nonyl, isodecyl, sec-decyl, tert-decyl, isododecyl, sec-dodecyl, tert-dodecyl, tert-tetradecyl and tert-pentadecyl.

[0144] Examples of the cycloalkyl group having 3 to 20 carbon atoms include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl and cyclodecyl, and polycyclic (eg, bicyclic, tricyclic or spirocyclic) alkyl groups formed by linking these monocyclic alkyl groups.

[0145] Among the above groups, as the alkyl group having no substituent, a straight-chain alkyl group such as a methyl group and an ethyl group is preferable.

[0146] Examples of a substituent which the alkyl group may have include an alkoxy group, a hydroxy group, a carboxyl group, a nitro group and a halogen atom (such as a fluorine atom, a bromine atom and an iodine atom).

[0147] Examples of the alkoxy group substituting the hydrogen atom contained in the alkyl group include: 11 ~R 18 The same groups as those represented by the alkoxy groups.

[0148] R in formula (1) 11 ~R 18 Examples of the alkoxy group represented include substituted or unsubstituted alkoxy groups.

[0149] R in the formula (1) having no substituent 11 ~R 18 The alkoxy group represented includes a straight chain alkoxy group, a branched alkoxy group or a cycloalkoxy group having 1 to 10 (preferably 1 to 6 and more preferably 1 to 4) carbon atoms.

[0150] Specific examples of straight chain alkoxy groups include methoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, n-hexoxy, n-heptoxy, n-octoxy, n-nonoxy and n-decoxy. Specific examples of branched alkoxy groups include isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentyl, neopentyl, tert-pentyl, isohexyl, sec-hexyl, tert-hexyl, isoheptyl, sec-heptyl, tert-heptyl, isooctyl, sec-octyl, tert-octyl, isononyl, sec-nonyl, tert-nonyl, isodecyl, sec-decyl and tert-decyl groups.

[0151] Specific examples of the cycloalkoxy group include a cyclopropyloxy group, a cyclobutyloxy group, a cyclopentyloxy group, a cyclohexyloxy group, a cycloheptyloxy group, a cyclooctyloxy group, a cyclononyloxy group and a cyclodecyloxy group.

[0152] Among these groups, as the alkoxy group having no substituent, a straight-chain alkoxy group is preferable.

[0153] Examples of a substituent which the alkoxy group may have include an aryl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (such as a fluorine atom, a bromine atom and an iodine atom).

[0154] Examples of the aryl group substituting the hydrogen atom contained in the alkoxy group include: 11 ~R 18 represents the same group as the aryl group.

[0155] Examples of the alkoxycarbonyl group substituting the hydrogen atom contained in the alkoxy group include: 11 ~R 18 The same groups as those represented by the alkoxycarbonyl group.

[0156] Examples of the aryloxycarbonyl group substituting the hydrogen atom contained in the alkoxy group include: 11 ~R 18 The same groups as those represented by the aryloxycarbonyl group.

[0157] R in formula (1) 11 ~R 18 Examples of the aralkyl group represented include aralkyl groups having a substituent or an unsubstituted group.

[0158] R in the formula (1) having no substituent 11 ~R 18 The aralkyl group represented is preferably an aralkyl group having 7 to 30 carbon atoms, more preferably an aralkyl group having 7 to 16 carbon atoms, and still more preferably an aralkyl group having 7 to 12 carbon atoms.

[0159] Examples of the unsubstituted aralkyl group having 7 to 30 carbon atoms include benzyl, phenylethyl, phenylpropyl, 4-phenylbutyl, phenylpentyl, phenylhexyl, phenylheptyl, phenyloctyl, phenylnonyl, naphthylmethyl, naphthylethyl, anthracenylmethyl and phenyl-cyclopentylmethyl.

[0160] Examples of a substituent which the aralkyl group may have include an alkoxy group, an alkoxycarbonyl group, an aryloxycarbonyl group and a halogen atom (such as a fluorine atom, a bromine atom and an iodine atom).

[0161] Examples of the alkoxy group substituting the hydrogen atom contained in the aralkyl group include: 11 ~R 18 The same groups as those represented by the alkoxy groups.

[0162] Examples of the alkoxycarbonyl group substituting the hydrogen atom contained in the aralkyl group include: 11 ~R 18 The same groups as those represented by the alkoxycarbonyl group.

[0163] Examples of the aryloxycarbonyl group substituting the hydrogen atom contained in the aralkyl group include: 11 ~R 18 The same groups as those represented by the aryloxycarbonyl group.

[0164] R in formula (1) 11 ~R 18 Examples of the aryl group represented include an aryl group having a substituent or an aryl group having no substituent.

[0165] R in the formula (1) having no substituent 11 ~R 18The aryl group represented by is preferably an aryl group having 6 to 30 carbon atoms, more preferably an aryl group having 6 to 14 carbon atoms, and still more preferably an aryl group having 6 to 10 carbon atoms.

[0166] Examples of the aryl group having 6 to 30 carbon atoms include phenyl, biphenyl, 1-naphthyl, 2-naphthyl, 9-anthryl, 9-phenanthryl, 1-pyrenyl, 5-butenyl, 1-indenyl, 2-azulyl, 9-fluorenyl, biphenylene, indacenyl, fluoranthenyl, acenaphthenyl, acetothrenyl, phenanthrenyl, fluorenyl, anthracenyl, bianthracenyl, trianthryl, tetraanthryl, anthraquinone, phenanthrenyl, triphenylene, pyrenyl, The preferred groups are phenyl, phenyl, octenyl, tetraphenyl, octenyl, rubenyl, and coronenyl.

[0167] Examples of a substituent which the aryl group may have include an alkyl group, an alkoxy group, an alkoxycarbonyl group, an aryloxycarbonyl group and a halogen atom (such as a fluorine atom, a bromine atom and an iodine atom).

[0168] Examples of the alkyl group substituting the hydrogen atom contained in the aryl group include: 11 ~R 18 represents the same group as the alkyl group.

[0169] Examples of the alkoxy group substituting the hydrogen atom contained in the aryl group include: 11 ~R 18 The same groups as those represented by the alkoxy groups.

[0170] Examples of the alkoxycarbonyl group substituting the hydrogen atom contained in the aryl group include: 11 ~R 18 The same groups as those represented by the alkoxycarbonyl group.

[0171] Examples of the aryloxycarbonyl group which replaces the hydrogen atom contained in the aryl group include: 11 ~R 18 The same groups as those represented by the aryloxycarbonyl group.

[0172] R in formula (1) 11 ~R 18 Examples of the aryloxy group represented by (—O—Ar, wherein Ar represents an aryl group) include aryloxy groups having a substituent or having no substituent.

[0173] R in the formula (1) having no substituent 11 ~R 18The aryloxy group represented is preferably an aryloxy group having 6 to 30 carbon atoms, more preferably an aryloxy group having 6 to 14 carbon atoms, and still more preferably an aryloxy group having 6 to 10 carbon atoms.

[0174] Examples of the aryloxy group having 6 to 30 carbon atoms include phenyloxy (phenoxy), biphenyloxy, 1-naphthyloxy, 2-naphthyloxy, 9-anthryloxy, 9-phenanthryloxy, 1-pyreneoxy, 5-butenyloxy, 1-indenyloxy, 2-azulyloxy, 9-fluorenyloxy, biphenyleneoxy, indaceneoxy, fluorantheneoxy, acenaphthyloxy, acetothrenyloxy, phenalenyloxy, fluorenyloxy, anthracenyloxy, bianthryloxy, trianthryloxy, tetraanthryloxy, anthraquinoneoxy, phenanthrenyloxy, triphenyleneoxy, pyreneoxy, The preferred groups include phenoxy, tetraphenoxy, preadenyloxy, phenoxy, peryloxy, pentphenoxy, pentacetyloxy, tetraphenoxy, hexacetyloxy, hexacetyloxy, rubenyloxy and coronaphenoxy. Among the above groups, phenyloxy (phenoxy) is preferred.

[0175] Examples of a substituent which the aryloxy group may have include an alkyl group, an alkoxycarbonyl group, an aryloxycarbonyl group and a halogen atom (such as a fluorine atom, a bromine atom and an iodine atom).

[0176] Examples of the alkyl group substituting the hydrogen atom contained in the aryloxy group include: 11 ~R 18 represents the same group as the alkyl group.

[0177] Examples of the alkoxycarbonyl group substituting the hydrogen atom contained in the aryloxy group include: 11 ~R 18 The same groups as those represented by the alkoxycarbonyl group.

[0178] Examples of the aryloxycarbonyl group substituting the hydrogen atom contained in the aryloxy group include R in the formula (1) having no substituent: 11 ~R 18 The same groups as those represented by the aryloxycarbonyl group.

[0179] R in formula (1) 11 ~R 18 Examples of the alkoxycarbonyl group (—CO—OR, wherein R represents an alkyl group) represented by include alkoxycarbonyl groups which may or may not have a substituent.

[0180] R in the formula (1) having no substituent 11 ~R 18 In the aryloxycarbonyl group represented by , the number of carbon atoms in the alkyl chain is preferably 1-20, more preferably 1-15, and even more preferably 1-10.

[0181] Examples of the alkoxycarbonyl group having 1 to 20 carbon atoms in the alkyl chain include methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, n-butoxycarbonyl, sec-butoxybutylcarbonyl, tert-butoxycarbonyl, pentyloxycarbonyl, hexyloxycarbonyl, heptyloxycarbonyl, octyloxycarbonyl, nonyloxycarbonyl, decyloxycarbonyl, dodecyloxycarbonyl, tridecyloxycarbonyl, tetradecyloxycarbonyl, pentadecyloxycarbonyl, hexadecyloxycarbonyl, heptadecyloxycarbonyl, octadecyloxycarbonyl, nonadecyloxycarbonyl and eicosyloxycarbonyl.

[0182] Examples of a substituent which the alkoxycarbonyl group may have include an aryl group, a hydroxyl group and a halogen atom (such as a fluorine atom, a bromine atom and an iodine atom).

[0183] Examples of the aryl group substituting the hydrogen atom contained in the alkoxycarbonyl group include: 11 ~R 18 represents the same group as the aryl group.

[0184] R in formula (1) 11 ~R 18 Examples of the aryloxycarbonyl group (—CO—OAr, wherein Ar represents an aryl group) represented by include aryloxycarbonyl groups which may or may not have a substituent.

[0185] In the formula (1) having no substituent, R 11 ~R 18 In the aryloxycarbonyl group represented by , the number of carbon atoms of the aryl group is preferably 6-30, more preferably 6-14, and even more preferably 6-10.

[0186] Examples of the aryloxycarbonyl group containing an aryl group having 6 to 30 carbon atoms include a phenoxycarbonyl group, a biphenyloxycarbonyl group, a 1-naphthyloxycarbonyl group, a 2-naphthyloxycarbonyl group, a 9-anthracenyloxycarbonyl group, a 9-phenanthrenyloxycarbonyl group, a 1-pyreneoxycarbonyl group, a 5-butanthraceneoxycarbonyl group, a 1-indenyloxycarbonyl group, a 2-azuleneoxycarbonyl group, a 9-fluorenyloxycarbonyl group, a biphenyleneoxycarbonyl group, an indaceneoxycarbonyl group, a fluorantheneoxycarbonyl group, an acenaphtheneoxycarbonyl group, an acetothrenyloxycarbonyl group, a phenalenyloxycarbonyl group, a fluorenyloxycarbonyl group, an anthraceneoxycarbonyl group, a bianthraceneoxycarbonyl group, a trianthraceneoxycarbonyl group, a tetraanthraceneoxycarbonyl group, an anthraquinoneoxycarbonyl group, a phenanthrenyloxycarbonyl group, a triphenyleneoxycarbonyl group, a pyreneoxycarbonyl group, oxycarbonyl, naphthacetoxycarbonyl, preadenyloxycarbonyl, phenoxycarbonyl, peryleneoxycarbonyl, pentacetoxycarbonyl, pentacetyloxycarbonyl, tetraphenoxycarbonyl, hexacetyloxycarbonyl, hexacetyloxycarbonyl, rubenyloxycarbonyl and coronaphenoxycarbonyl. Among the above groups, phenoxycarbonyl is preferred.

[0187] Examples of a substituent which the aryloxycarbonyl group may have include an alkyl group, a hydroxyl group and a halogen atom (such as a fluorine atom, a bromine atom and an iodine atom).

[0188] Examples of the alkyl group substituting the hydrogen atom contained in the aryloxycarbonyl group include: 11 ~R 18 represents the same group as the alkyl group.

[0189] R in formula (1) 11 ~R 18 The alkoxycarbonylalkyl group (-(C n H 2n Examples of the group ()-CO-OR, wherein R represents an alkyl group and n represents an integer of 1 or more) include substituted or unsubstituted alkoxycarbonylalkyl groups.

[0190] R in the formula (1) having no substituent 11 ~R 18 Examples of the alkoxycarbonyl group (-CO-OR) in the alkoxycarbonylalkyl group represented by include 11 ~R 18 The same groups as those represented by the alkoxycarbonyl group.

[0191] R in the formula (1) having no substituent 11 ~R 18 The alkylene chain (-C n H 2n Examples of the alkylene group (alkylene group) include a linear alkylene chain having 1 to 20 carbon atoms (preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms), a branched alkylene chain having 3 to 20 carbon atoms (preferably 3 to 10 carbon atoms), and a cyclic alkylene chain having 3 to 20 carbon atoms (preferably 3 to 10 carbon atoms).

[0192] Examples of the linear alkylene chain having 1 to 20 carbon atoms include methylene, ethylene, n-propylene, n-butylene, n-pentylene, n-hexylene, n-heptylene, n-octylene, n-nonylene, n-decylene, n-undecylene, n-dodecylene, tridecylene, n-tetradecylene, n-pentadecylene, n-heptadecylene, n-octadecylene, n-nonadecylene and n-eicosylene.

[0193] Examples of branched alkylene chains having 3 to 20 carbon atoms include isopropylene, isobutylene, secondary butylene, tert-butylene, isopentylene, neopentylene, tert-pentylene, isohexylene, secondary hexylene, tert-hexylene, isoheptylene, secondary heptylene, tert-heptylene, isooctylene, secondary octylene, tert-octylene, isononylene, secondary nonylene, tert-nonylene, isodecylene, secondary decylene, tert-decylene, isododecylene, secondary dodecylene, tert-dodecylene, tert-tetradecylene and tert-pentadecylene.

[0194] Examples of the cyclic alkylene group having 3 to 20 carbon atoms include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, a cyclooctylene group, a cyclononylene group, and a cyclodecylene group.

[0195] Examples of a substituent which the alkoxycarbonylalkyl group may have include an aryl group, a hydroxyl group and a halogen atom (such as a fluorine atom, a bromine atom and an iodine atom).

[0196] Examples of the aryl group substituting the hydrogen atom contained in the alkoxycarbonylalkyl group include: 11 ~R 18 represents the same group as the aryl group.

[0197] R in formula (1) 11 ~R 18 The aryloxycarbonylalkyl (-(C n H 2n Examples of the group ()-CO-OAr (wherein Ar represents an aryl group and n represents an integer of 1 or more) include substituted or unsubstituted aryloxycarbonylalkyl groups.

[0198] R in the formula (1) having no substituent 11 ~R 18 Examples of the aryloxycarbonyl group (—CO—OAr, wherein Ar represents an aryl group) in the aryloxycarbonylalkyl group represented by 11 ~R 18 The same groups as those represented by the aryloxycarbonyl group.

[0199] R in the formula (1) having no substituent 11 ~R 18 The alkylene chain (-C n H 2n Examples of -) include R in formula (1) 11 ~R 18 The alkylene chain in the alkoxycarbonylalkyl group represented by the present invention is the same as that of the alkylene chain in the alkoxycarbonylalkyl group represented by the present invention.

[0200] Examples of a substituent which the aryloxycarbonylalkyl group may have include an alkyl group, a hydroxy group and a halogen atom (such as a fluorine atom, a bromine atom and an iodine atom).

[0201] Examples of the alkyl group substituting the hydrogen atom contained in the aryloxycarbonylalkyl group include: 11 ~R 18 represents the same group as the alkyl group.

[0202] R in formula (1) 11 ~R 18 Examples of the halogen atom represented by include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0203] R in formula (1) 11 and R 12 , R 12 and R 13 , R 13 and R 14 , R 15 and R 16 , R 16 and R 17 or R 17 and R 18 Examples of the ring formed by connecting to each other include a benzene ring and a condensed ring having 10 to 18 carbon atoms (such as a naphthalene ring, anthracene ring, phenanthrene ring, ring (benzo[α]phenanthrene ring), tetracene ring, tetracene ring (benzo[α]anthracene ring) and triphenylene ring). In the above structures, the structure of the ring to be formed is preferably a benzene ring.

[0204] R in formula (2) 21 ~R 28 Examples of the alkyl group represented by include the following: 11 ~R 18 represents the same group as the alkyl group.

[0205] R in formula (2) 21 ~R 28 Examples of the alkoxy group represented by include the following: 11 ~R 18 The same groups as those represented by the alkoxy groups.

[0206] R in formula (2) 21 ~R 28 Examples of the aralkyl group represented by include the following: 11 ~R 18 The same groups as those represented by the aralkyl groups.

[0207] R in formula (2) 21 ~R 28 Examples of the aryl group represented by include 11 ~R 18 represents the same group as the aryl group.

[0208] R in formula (2) 21 ~R 28 Examples of the aryloxy group represented by include 11 ~R 18 The same groups as those represented by the aryloxy groups.

[0209] R in formula (2) 21 ~R 28 Examples of the alkoxycarbonyl group represented by include 11 ~R 18 The same groups as those represented by the alkoxycarbonyl group.

[0210] R in formula (2) 21 ~R 28 Examples of the aryloxycarbonyl group represented by the formula (1) include 11 ~R 18 The same groups as those represented by the aryloxycarbonyl group.

[0211] R in formula (2) 21 ~R 28 Examples of the alkoxycarbonylalkyl group represented by the formula (1) include 11 ~R 18 The same groups as those represented by the alkoxycarbonylalkyl group.

[0212] R in formula (2) 21 ~R 28 Examples of the aryloxycarbonylalkyl group represented by the formula (1) include 11 ~R 18 The same groups as those represented by the aryloxycarbonylalkyl group.

[0213] R in formula (2) 21 ~R 28 Examples of the halogen atom represented by include 11 ~R 18 The halogen atoms represented are the same atoms.

[0214] R in formula (2) 21 and R 22 , R 22 and R 23 , R 23 and R 24 , R 25 and R 26 , R 26 and R 27 or R 27 and R 28 Examples of the ring formed by connecting to each other include a benzene ring and a condensed ring having 10 to 18 carbon atoms (such as a naphthalene ring, anthracene ring, phenanthrene ring, In the above structures, the structure of the ring to be formed is preferably a benzene ring.

[0215] From the viewpoint of preventing the degradation of photosensitivity and the increase of residual potential when repeatedly forming images, R in formula (1) 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 Each independently is preferably a hydrogen atom, an alkyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group or an aryloxycarbonylalkyl group.

[0216] From the viewpoint of preventing the degradation of photosensitivity and the increase of residual potential that occur when repeatedly forming images, R in formula (2) 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 and R 28 Each independently is preferably a hydrogen atom, an alkyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group or an aryloxycarbonylalkyl group.

[0217] Hereinafter, specific examples of the pyrenone compound (1) and the pyrenone compound (2) are shown, but are not limited thereto. In the following formulae, Ph represents a phenyl group.

[0218]

[0219]

[0220]

[0221]

[0222]

[0223]

[0224] The pyrone compound (1-1) and the pyrone compound (2-1) are in an isomer relationship (a relationship between a cis configuration and a trans configuration). Therefore, according to the synthesis method, a mixture of the two compounds tends to be obtained, and the mixing ratio thereof is usually 1:1. With respect to the mixture of the pyrone compound (1-1) and the pyrone compound (2-1), one of the compounds can be purified from the mixture according to a known purification method. The other pyrone compounds in the relationship between the cis configuration and the trans configuration have the same relationship as described above.

[0225] From the viewpoint of controlling the volume resistivity of the undercoat layer so as to provide a volume resistivity falling within the preferred range described later and obtaining film-forming properties, the total content of the pyrenone compound (1) and the pyrenone compound (2) is preferably 30% to 90% by weight, more preferably 40% to 80% by weight, and even more preferably 50% to 70% by weight relative to the total solid content of the undercoat layer.

[0226] -Polyurethane-

[0227] Generally, polyurethanes are synthesized by the polyaddition reaction of polyfunctional isocyanates and polyols.

[0228] Examples of the polyfunctional isocyanate include diisocyanates such as methylene diisocyanate, ethylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,3-xylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 3,3'-dimethylbiphenyl diisocyanate, 4,4'-biphenyl diisocyanate, dicyclohexylmethane diisocyanate, and methylene di(4-cyclohexyl isocyanate); isocyanurates obtained by trimerizing isocyanates; and blocked isocyanates obtained by blocking the isocyanate group of a diisocyanate with a blocking agent. One polyfunctional isocyanate may be used alone, or two or more thereof may be used in combination.

[0229] Examples of the polyol include diols such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 2,2-dimethyl-1,3-propylene glycol, 1,2-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 2,4-pentanediol, 3,3-dimethyl-1,2-butylene glycol, 2-ethyl-2-methyl-1,3-propylene glycol, 1,2-hexanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 2,2-diethyl-1,3- Propylene glycol, 2,4-dimethyl-2,4-pentanediol, 1,7-heptanediol, 2-methyl-2-propyl-1,3-propanediol, 2,5-dimethyl-2,5-hexanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,4-cyclohexanedimethanol, hydroquinone, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, polypropylene glycol, poly(oxytetramethylene) glycol, 4,4'-dihydroxy-diphenyl-2,2-propane and 4,4'-dihydroxyphenyl sulfone.

[0230] Examples of the polyol also include polyester polyol, polycarbonate polyol, polycaprolactone polyol, polyether polyol, and polyvinyl butyral.

[0231] One type of polyol may be used alone, or two or more types thereof may be used in combination.

[0232] The primer layer may contain other resins as a binder resin in addition to the polyurethane.

[0233] Examples of other resins include polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyester resins, unsaturated polyester resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, urea resins, phenol resins, phenol-formaldehyde resins, melamine resins, alkyd resins, and epoxy resins.

[0234] In the binder resin contained in the undercoat layer, the content of the polyurethane is preferably 80 to 100 wt %, more preferably 90 to 100 wt %, still more preferably 95 to 100 wt %, based on the total amount of the binder resin.

[0235] The weight ratio of the total content of the pyrone compound (1) and the pyrone compound (2) contained in the primer layer to the content of the polyurethane contained in the primer layer (pyrone compound:polyurethane) is preferably 40:60 to 80:20, more preferably 50:50 to 70:30.

[0236] -Organic acid metal salts and metal organic complexes-

[0237] The primer layer may contain at least one of an organic acid metal salt and a metal organic complex. At least one of the organic acid metal salt and the metal organic complex contained in the primer layer may be an organic acid metal salt or a metal organic complex that acts as a urethane curing catalyst (i.e., a catalyst for the addition polymerization of polyfunctional isocyanates and polyols) when forming the primer layer.

[0238] Examples of metals forming organic acid metal salts or metal organic complexes include bismuth, aluminum, zirconium, zinc, cobalt, iron, nickel, copper, tin, platinum and palladium. The organic acid of the organic acid metal salt is preferably a monovalent carboxylic acid. As the monovalent carboxylic acid, octanoic acid, cyclohexane acid or salicylic acid is preferred, and octanoic acid is more preferred.

[0239] From the viewpoint of preventing the residual potential from rising when repeatedly forming images, the at least one of the organic acid metal salt and the metal organic complex contained in the undercoat layer is preferably an organic acid metal salt and a metal organic complex each containing a metal selected from the group consisting of bismuth, aluminum, zirconium, zinc, cobalt, iron, nickel and copper, and more preferably an organic acid metal salt and a metal organic complex each containing a metal selected from the group consisting of bismuth, aluminum and zirconium.

[0240] Examples of the organic acid metal salt or metal organic complex containing bismuth include bismuth octoate, bismuth naphthenate, and bismuth salicylate; and K-KAT348, K-KAT XC-C227, K-KAT XK-628, and K-KATXK-640 manufactured by King Industries, Inc.

[0241] Examples of the organic acid metal salt or metal organic complex containing aluminum include: aluminum octoate, aluminum naphthenate, and aluminum salicylate; and K-KAT 5218 manufactured by King Industries, Inc.

[0242] Examples of the organic acid metal salt or metal organic complex containing zirconium include: zirconium octanoate, zirconium naphthenate, and zirconium salicylate; and K-KAT 4205, K-KAT 6212, and K-KAT A209 manufactured by King Industries, Inc.

[0243] Examples of the organic acid metal salt or metal organic complex containing zinc include zinc octoate, zinc naphthenate, and zinc salicylate.

[0244] Examples of the organic acid metal salt or metal organic complex containing cobalt include cobalt octoate, cobalt naphthenate, and cobalt salicylate.

[0245] Examples of the organic acid metal salt or metal organic complex containing iron include iron octoate, iron naphthenate, and iron salicylate.

[0246] Examples of the organic acid metal salt or metal organic complex containing nickel include nickel octoate, nickel naphthenate, and nickel salicylate.

[0247] Examples of the copper-containing organic acid metal salt or metal organic complex include copper octoate, copper naphthenate, and copper salicylate.

[0248] Only one kind of the organic acid metal salt or the metal organic complex may be used alone, or two or more kinds thereof may be used in combination.

[0249] In the case where the primer layer contains at least one of an organic acid metal salt and a metal organic complex, the total content of the organic acid metal salt and the metal organic complex is preferably 0.001 wt % to 3 wt %, more preferably 0.003 wt % to 2 wt %, even more preferably 0.01 wt % to 1 wt %, and even more preferably 0.05 wt % to 0.5 wt % relative to the total solid content of the primer layer.

[0250] -Metal oxide particles-

[0251] From the viewpoint of preventing leakage due to adhesion of foreign matter to the photoreceptor, the undercoat layer preferably contains metal oxide particles. Examples of the metal oxide particles include zinc oxide particles, titanium oxide particles, tin oxide particles, and zirconium oxide particles, preferably zinc oxide particles, titanium oxide particles, or tin oxide particles.

[0252] The volume average particle diameter of the metal oxide particles is preferably 10 nm to 2,000 nm, more preferably 50 nm to 1,000 nm, and still more preferably 60 nm to 500 nm.

[0253] The BET specific surface area of ​​the metal oxide particles is preferably 10 m 2 / g or above.

[0254] The metal oxide particles may be surface treated. Examples of surface treatment agents for metal oxide particles include silane coupling agents, titanate coupling agents, aluminum coupling agents, and surfactants. Two or more metal oxide particles of different types, different surface treatments, or different particle sizes may be mixed and used.

[0255] In the case where the undercoat layer contains metal oxide particles to prevent leakage due to adhesion of foreign matter to the photoreceptor, the content of the metal oxide particles is preferably 1 wt % or more and less than 30 wt %, more preferably 5 wt % to 25 wt %, and even more preferably 10 wt % to 20 wt % relative to the total solid content of the undercoat layer.

[0256] The undercoat layer may contain various additives to improve electrical properties, environmental stability, and image quality.

[0257] Examples of additives include known materials such as electron transport pigments (such as polycyclic condensed type and azo type), zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, alkoxytitanium compounds, organic titanium compounds and silane coupling agents. The silane coupling agent is used for the surface treatment of the above-mentioned metal oxide particles and can also be further added to the primer as an additive.

[0258] Examples of the silane coupling agent as the additive include vinyltrimethoxysilane, 3-methacryloxypropyl-tri(2-methoxyethoxy)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane.

[0259] Examples of the zirconium chelate compound include zirconium butoxide, zirconium ethyl acetoacetate, zirconium acetylacetonate butoxy, zirconium ethyl acetoacetate butoxy, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octanoate, zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, zirconium methacrylate butoxy, zirconium stearate butoxy, and zirconium isostearate butoxy.

[0260] 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, titanium ammonium lactate, titanium lactate, titanium ethyl lactate, and polyhydroxytitanium stearate.

[0261] Examples of the aluminum chelate compound include aluminum isopropoxide, diisopropylmonobutoxyaluminum, aluminum butyrate, diethyl acetoacetate aluminum diisopropoxide, and tris(ethyl acetoacetate)aluminum.

[0262] These additives may be used alone or as a mixture or polycondensate of a plurality of compounds.

[0263] From the viewpoint of leakage resistance, the thickness of the primer layer is preferably 3 μm or more, more preferably 5 μm or more. From the viewpoint of preventing the residual potential from increasing during repeated use, the thickness of the primer layer is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less.

[0264] The volume resistivity of the primer layer is preferably 1×10 10 Ω·cm~1×10 12 Ω·cm.

[0265] The primer layer preferably has a Vickers hardness of 35 or more.

[0266] In order to prevent moire fringes, the surface roughness (ten-point average roughness) of the undercoat layer may be adjusted to 1 / (4n) (n is the refractive index of the upper layer) to 1 / 2 of the exposure laser wavelength λ.

[0267] In order to adjust the surface roughness, resin particles or the like may be added to the primer layer. Examples of resin particles include silicone resin particles and cross-linked polymethyl methacrylate resin particles. Furthermore, in order to adjust the surface roughness, the surface of the primer layer may be polished. Examples of polishing methods include buffing, sandblasting, wet honing, and grinding.

[0268] The formation of the undercoat layer is not particularly limited, and a known formation method can be used. For example, a coating film of an undercoat layer-forming coating liquid obtained by adding the above-mentioned components to a solvent is formed, and the coating film is dried by heating as necessary to form the undercoat layer.

[0269] 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.

[0270] 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, methylene chloride, chloroform, chlorobenzene and toluene.

[0271] Since the pyrenone compound (1) and the pyrenone compound (2) are not easily soluble in an organic solvent, it is preferred to disperse the pyrenone compound (1) and the pyrenone compound (2) in an organic solvent. Examples of the dispersion method 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 stirrer. In the case where the metal oxide particles are mixed in the undercoat layer, it is preferred to disperse the metal oxide particles in the organic solvent by the same method.

[0272] Examples of a method for applying the undercoat layer-forming coating liquid onto the conductive substrate include general methods such as knife coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0273] Hereinafter, the undercoat layer of the second photoreceptor will be described in detail.

[0274] [Base coating]

[0275] The primer layer contains at least one pyrone compound selected from the group consisting of compounds represented by formula (1) (pyrone compound (1)) and compounds represented by formula (2) (pyrone compound (2)), and at least one acceptor compound selected from the group consisting of compounds represented by any one of formulas (3) to (15). The primer layer may further contain a binder resin, inorganic particles, and the like.

[0276] The compound represented by formula (1) and the compound represented by formula (2) used in the second photoreceptor are the same as the compound represented by formula (1) and the compound represented by formula (2) used in the first photoreceptor. The description of the compound represented by formula (1) and the compound represented by formula (2) used in the first photoreceptor can also be applied to the compound represented by formula (1) and the compound represented by formula (2) used in the second photoreceptor.

[0277] Here, from the viewpoint of controlling the volume resistivity of the undercoat layer to provide a volume resistivity falling within a preferred range, the total content of the pyrenone compound (1) and the pyrenone compound (2) is preferably 50% by weight to 90% by weight, more preferably 55% by weight to 80% by weight, and still more preferably 60% by weight to 70% by weight relative to the total solid content of the undercoat layer.

[0278] -Receptor Compounds-

[0279] The primer layer contains at least one receptor compound selected from the group consisting of a compound represented by formula (3) shown below, a compound represented by formula (4), a compound represented by formula (5), a compound represented by formula (6), a compound represented by formula (7), a compound represented by formula (8), a compound represented by formula (9), a compound represented by formula (10), a compound represented by formula (11), a compound represented by formula (12), a compound represented by formula (13), a compound represented by formula (14) and a compound represented by formula (15).

[0280]

[0281] In formula (3), Z represents C(COOR k1 )2(where R k1 is a hydrogen atom or an alkyl group), C(CN)2, O (oxygen atom) or N-CN, R 31 , R 32 , R 33 , R 34 , R 35 , R 36 , R 37 and R 38 each independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, a carboxyl group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a nitro group or -CR k2 =CRk3 R k4 The group represented by k2 represents a hydrogen atom or an alkyl group, R k3 and R k4 Each independently represents a hydrogen atom or a phenyl group, provided that R k3 and R k4 At least one of them represents a phenyl group. ).

[0282] In formula (3), C(COOR k1 )2, in R k1 In the case of an alkyl group, R k1 Examples of include straight chain, branched or cyclic alkyl groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. k1 They may be the same as or different from each other. k1 , preferably a hydrogen atom.

[0283] Examples of the halogen atom in the formula (3) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0284] Examples of the alkyl group in formula (3) include linear, branched or cyclic alkyl groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkyl group in formula (3) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0285] Examples of the alkoxy group in formula (3) include straight chain, branched or cyclic alkoxy groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkoxy group in formula (3) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0286] Examples of the aralkyl group in formula (3) include aralkyl groups having 7 to 20 (preferably 7 to 15, more preferably 7 to 12) carbon atoms, and specific examples thereof include benzyl and phenethyl. The aralkyl group in formula (3) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group, and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom).

[0287] Examples of the aryl group in formula (3) include aryl groups having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms, and specific examples thereof include phenyl, biphenyl, 1-naphthyl and 2-naphthyl. The aryl group in formula (3) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0288] Examples of the aryloxy group in formula (3) include aryloxy groups having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms, and specific examples thereof include phenoxy, biphenyloxy, 1-naphthyloxy and 2-naphthyloxy. The aryloxy group in formula (3) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0289] Examples of the alkylcarbonyl group (-CO-R, wherein R represents an alkyl group) in formula (3) include alkylcarbonyl groups having an alkyl group having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkyl group in the alkylcarbonyl group may be linear or branched. The alkyl group in the alkylcarbonyl group may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an aryl group, and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom).

[0290] Examples of the arylcarbonyl group (-CO-Ar, wherein Ar represents an aryl group) in formula (3) include arylcarbonyl groups having an aryl group having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms. Specific examples of the aryl group in the arylcarbonyl group include phenyl, biphenyl, 1-naphthyl and 2-naphthyl. The aryl group in the arylcarbonyl group may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0291] Examples of the alkoxycarbonyl group (-CO-OR, wherein R represents an alkyl group) in formula (3) include alkoxycarbonyl groups having an alkyl group having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkyl group in the alkoxycarbonyl group may be linear or branched. The alkyl group in the alkoxycarbonyl group may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an aryl group, and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom).

[0292] Examples of the aryloxycarbonyl group (-CO-OAr, wherein Ar represents an aryl group) in formula (3) include aryloxycarbonyl groups having an aryl group having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms. Specific examples of the aryl group in the aryloxycarbonyl group include phenyl, biphenyl, 1-naphthyl and 2-naphthyl. The aryl group in the aryloxycarbonyl group may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0293] In formula (3), -CR k2 =CR k3 R k4 In the group represented by R k2 In the case of an alkyl group, R k2 Examples include linear, branched or cyclic alkyl groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms.

[0294] In formula (3), Z is preferably C(CN)2 or C(COOR k1 )2, more preferably C(CN)2 or C(COOH)2, and even more preferably C(CN)2.

[0295] In formula (3), R 31 and R 35 Each is preferably a hydrogen atom, a halogen atom or an alkyl group, and more preferably a hydrogen atom.

[0296] In formula (3), R 32 and R 36 Each is preferably a hydrogen atom, a halogen atom, an alkyl group or a nitro group.

[0297] In formula (3), R 33 , R 34 , R 37 and R 38 Preferably, R 33 , R 34 , R 37 and R 38 At least one of them is preferably a carboxyl group or an alkoxycarbonyl group.

[0298] Acceptor compounds (3-1) to (3-10) are shown below as specific examples of the compound represented by formula (3), but the examples are not limited thereto.

[0299]

[0300] In formula (4), R 41 , R 42 , R 43 and R 44 Each independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, a nitro group, a carboxyl group or a hydroxyl group.

[0301] Examples of the halogen atom in the formula (4) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0302] Examples of the alkyl group in formula (4) include a linear, branched or cyclic alkyl group having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkyl group in formula (4) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0303] Examples of the alkoxy group in formula (4) include straight chain, branched or cyclic alkoxy groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkoxy group in formula (4) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0304] Examples of the aralkyl group in formula (4) include aralkyl groups having 7 to 20 (preferably 7 to 15, more preferably 7 to 12) carbon atoms, and specific examples thereof include benzyl and phenethyl. The aralkyl group in formula (4) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group, and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom).

[0305] Examples of the aryl group in formula (4) include aryl groups having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms, and specific examples thereof include phenyl, biphenyl, 1-naphthyl and 2-naphthyl. The aryl group in formula (4) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0306] Examples of the aryloxy group in formula (4) include aryloxy groups having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms, and specific examples thereof include phenoxy, biphenyloxy, 1-naphthyloxy and 2-naphthyloxy. The aryloxy group in formula (4) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0307] In formula (4), R 41 , R 42 , R 43 and R 44 Among them, it is preferred that two or three groups are hydrogen atoms, and it is more preferred that two groups are hydrogen atoms.

[0308] Acceptor compounds (4-1) to (4-10) are shown below as specific examples of the compound represented by formula (4), but the examples are not limited thereto.

[0309]

[0310]

[0311] In formula (5), R 51 , R 52 , R 53 , R 54 , R 55 and R 56 Each independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, a nitro group, a carboxyl group or a hydroxyl group.

[0312] Examples of the halogen atom in the formula (5) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0313] Examples of the alkyl group in formula (5) include straight chain, branched or cyclic alkyl groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkyl group in formula (5) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0314] Examples of the alkoxy group in formula (5) include straight chain, branched or cycloalkoxy groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkoxy group in formula (5) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0315] Examples of the aralkyl group in formula (5) include aralkyl groups having 7 to 20 (preferably 7 to 15, more preferably 7 to 12) carbon atoms, and specific examples thereof include benzyl and phenethyl. The aralkyl group in formula (5) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group, and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom).

[0316] Examples of the aryl group in formula (5) include aryl groups having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms, and specific examples thereof include phenyl, biphenyl, 1-naphthyl and 2-naphthyl. The aryl group in formula (5) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0317] Examples of the aryloxy group in formula (5) include aryloxy groups having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms, and specific examples thereof include phenoxy, biphenyloxy, 1-naphthyloxy and 2-naphthyloxy. The aryloxy group in formula (5) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0318] In formula (5), R 51 and R 52 Each is preferably a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a nitro group, a carboxyl group or a hydroxyl group.

[0319] In formula (5), R 53 and R 56 Each is preferably a hydrogen atom, a halogen atom or an alkyl group, and more preferably a hydrogen atom.

[0320] In formula (5), R 54 and R 55Each is preferably a hydrogen atom, a halogen atom, an alkyl group or a carboxyl group.

[0321] Acceptor compounds (5-1) to (5-10) are shown below as specific examples of the compound represented by formula (5), but the examples are not limited thereto.

[0322]

[0323] In formula (6), R 61 , R 62 , R 63 , R 64 , R 65 , R 66 , R 67 and R 68 Each independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, a nitro group, a carboxyl group or a hydroxyl group.

[0324] Examples of the halogen atom in the formula (6) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0325] Examples of the alkyl group in formula (6) include linear, branched or cyclic alkyl groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkyl group in formula (6) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0326] Examples of the alkoxy group in formula (6) include straight chain, branched or cycloalkoxy groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkoxy group in formula (6) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0327] Examples of the aralkyl group in formula (6) include aralkyl groups having 7 to 20 (preferably 7 to 15, more preferably 7 to 12) carbon atoms, and specific examples thereof include benzyl and phenethyl. The aralkyl group in formula (6) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group, and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom).

[0328] Examples of the aryl group in formula (6) include aryl groups having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms, and specific examples thereof include phenyl, biphenyl, 1-naphthyl and 2-naphthyl. The aryl group in formula (6) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0329] Examples of the aryloxy group in formula (6) include aryloxy groups having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms, and specific examples thereof include phenoxy, biphenyloxy, 1-naphthyloxy and 2-naphthyloxy. The aryloxy group in formula (6) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0330] The compound represented by formula (6) preferably has a total of one or two at least one group selected from alkyl, alkoxy, hydroxy, carboxyl and nitro in the molecule, and more preferably has one or two alkyl, one or two alkoxy, one or two hydroxy or one or two carboxyl groups. The alkyl is preferably a straight-chain or branched alkyl having 1 to 4 carbon atoms, more preferably a methyl or ethyl group. The alkoxy is preferably a straight-chain or branched alkoxy having 1 to 4 carbon atoms, more preferably a methoxy or ethoxy group.

[0331] Acceptor compounds (6-1) to (6-10) are shown below as specific examples of the compound represented by formula (6), but the examples are not limited thereto.

[0332]

[0333]

[0334] In formula (7), R 71 and R 72 Each independently represents a hydrogen atom, a cyano group or a monovalent organic group having an aromatic ring, and R 71 and R 72 Can be connected to each other to form a ring.

[0335] In R 71 and R 72 In the case of connecting to each other to form a ring, examples of the structure of the formed ring include an aromatic ring and an alicyclic ring, and specific examples thereof include benzene, naphthalene, phenanthrene, cyclopentane, cyclohexane, cycloheptane, 3,5-dimethylcyclohexane, 3,5-diethylcyclohexane, 3,5-diisopropylcyclohexane, 3,3,5-trimethylcyclohexane and 3,3,5,5-tetramethylcyclohexane.

[0336] Examples of the aromatic ring in the monovalent organic group having an aromatic ring include benzene, naphthalene, anthracene and phenanthrene, with benzene being preferred.

[0337] The monovalent organic group having an aromatic ring is preferably an organic group represented by the following formula (7-1).

[0338]

[0339] In formula (7-1), R 73represents a halogen atom, an alkyl group, a nitro group, a carboxyl group or a hydroxyl group, n represents an integer of 0 to 5, and * represents the connection position to the carbon atom.

[0340] Examples of the halogen atom in the formula (7-1) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0341] Examples of the alkyl group in formula (7-1) include linear, branched or cyclic alkyl groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkyl group in formula (7-1) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0342] In the formula (7-1), n ​​represents an integer of 0 to 5, preferably an integer of 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0343] The compound represented by formula (7) is preferably 71 and R 72 At least one of which is a monovalent organic group having an aromatic ring, more preferably R 71 and R 72 A compound in which one of the two is a monovalent organic group having an aromatic ring and the other is a hydrogen atom or a cyano group.

[0344] Acceptor compounds (7-1) to (7-10) are shown below as specific examples of the compound represented by formula (7), but the examples are not limited thereto.

[0345]

[0346] In formula (8), R 81 , R 82 , R 83 , R 84 , R 85 , R 86 , R 87 and R 88 Each independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, a nitro group, a carboxyl group or a hydroxyl group, and R 81 and R 82 Can be connected to each other to form a ring, R 83 and R 84 Can be connected to each other to form a ring, R 85 and R 86 can be connected to each other to form a ring, and R 87 and R 88 Can be connected to each other to form a ring.

[0347] In R 81 and R 82 , R 83 and R 84, R 85 and R 86 or R 87 and R 88 In the case of connecting to each other to form a ring, examples of the structure of the formed ring include an aromatic ring and an alicyclic ring, and specific examples thereof include benzene, naphthalene, phenanthrene, cyclopentane, cyclohexane, cycloheptane, 3,5-dimethylcyclohexane, 3,5-diethylcyclohexane, 3,5-diisopropylcyclohexane, 3,3,5-trimethylcyclohexane and 3,3,5,5-tetramethylcyclohexane.

[0348] Examples of the halogen atom in the formula (8) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0349] Examples of the alkyl group in formula (8) include straight chain, branched or cycloalkyl groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkyl group in formula (8) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom). The alkyl group in formula (8) is preferably a branched alkyl group, which may be substituted with a carboxyl group.

[0350] Examples of the alkoxy group in formula (8) include straight chain, branched or cycloalkoxy groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkoxy group in formula (8) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0351] Examples of the aralkyl group in formula (8) include aralkyl groups having 7 to 20 (preferably 7 to 15, more preferably 7 to 12) carbon atoms, and specific examples thereof include benzyl and phenethyl. The aralkyl group in formula (8) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group, and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom).

[0352] Examples of the aryl group in formula (8) include aryl groups having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms, and specific examples thereof include phenyl, biphenyl, 1-naphthyl and 2-naphthyl. The aryl group in formula (8) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0353] Examples of the aryloxy group in formula (8) include aryloxy groups having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms, and specific examples thereof include phenoxy, biphenyloxy, 1-naphthyloxy and 2-naphthyloxy. The aryloxy group in formula (8) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0354] In formula (8), R81 , R 82 , R 83 , R 84 , R 85 , R 86 , R 87 and R 88 Each preferably represents a hydrogen atom, a halogen atom or an alkyl group, and it is also preferred that adjacent groups thereof are linked to each other to form a benzene ring.

[0355] Acceptor compounds (8-1) to (8-10) are shown below as specific examples of the compound represented by formula (8), but the examples are not limited thereto.

[0356]

[0357] In formula (9), R 91 and R 92 Each independently represents a hydrogen atom, an alkyl group, an aralkyl group or an aryl group; and x represents an integer, preferably an integer of 2 to 6.

[0358] Examples of the alkyl group in formula (9) include straight-chain, branched or cycloalkyl groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkyl group in formula (9) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom). The alkyl group in formula (9) is preferably a straight-chain alkyl group.

[0359] Examples of the aralkyl group in formula (9) include aralkyl groups having 7 to 20 (preferably 7 to 15, more preferably 7 to 12) carbon atoms, and specific examples thereof include benzyl and phenethyl. The aralkyl group in formula (9) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group, and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom).

[0360] Examples of the aryl group in formula (9) include aryl groups having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms, and specific examples thereof include phenyl, biphenyl, 1-naphthyl and 2-naphthyl. The aryl group in formula (9) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0361] Acceptor compounds (9-1) to (9-10) are shown below as specific examples of the compound represented by formula (9), but the examples are not limited thereto.

[0362]

[0363] In formula (10), X 1 , X 2 and X 3Each independently represents CH or a nitrogen atom, R 101 , R 102 and R 103 Each independently represents a halogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, a nitro group, a carboxyl group or a hydroxyl group, and n1, n2 and n3 each independently represent an integer of 0-5.

[0364] When n1 is 2 or more, multiple R 101 May be the same as or different from each other.

[0365] When n2 is 2 or more, the presence of multiple R 102 May be the same as or different from each other.

[0366] When n3 is 2 or more, the presence of multiple R 103 May be the same as or different from each other.

[0367] In formula (10), X 1 , X 2 and X 3 Each independently represents CH or a nitrogen atom, X 1 , X 2 and X 3 Preferably, they are all nitrogen atoms.

[0368] Examples of the halogen atom in the formula (10) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0369] Examples of the alkyl group in formula (10) include linear, branched or cyclic alkyl groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkyl group in formula (10) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0370] Examples of the alkoxy group in formula (10) include linear, branched or cyclic alkoxy groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkoxy group in formula (10) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0371] Examples of the aralkyl group in formula (10) include aralkyl groups having 7 to 20 (preferably 7 to 15, more preferably 7 to 12) carbon atoms, and specific examples thereof include benzyl and phenethyl. The aralkyl group in formula (10) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group, and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom).

[0372] Examples of the aryl group in formula (10) include aryl groups having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms, and specific examples thereof include phenyl, biphenyl, 1-naphthyl and 2-naphthyl. The aryl group in formula (10) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0373] Examples of the aryloxy group in formula (10) include aryloxy groups having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms, and specific examples thereof include phenoxy, biphenyloxy, 1-naphthyloxy and 2-naphthyloxy. The aryloxy group in formula (10) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0374] In formula (10), n1, n2 and n3 each independently represent an integer of 0 to 5, preferably an integer of 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0375] Acceptor compounds (10-1) to (10-10) are shown below as specific examples of the compound represented by the formula (10), but the examples are not limited thereto.

[0376]

[0377]

[0378] In formula (11), R 111 and R 112 Each independently represents a halogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, a nitro group, a carboxyl group or a hydroxyl group, and n1 and n2 each independently represent an integer of 0 to 5.

[0379] When n1 is 2 or more, multiple R 111 May be the same as or different from each other.

[0380] When n2 is 2 or more, the presence of multiple R 112 May be the same as or different from each other.

[0381] Examples of the halogen atom in the formula (11) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0382] Examples of the alkyl group in formula (11) include linear, branched or cyclic alkyl groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkyl group in formula (11) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0383] Examples of the alkoxy group in formula (11) include straight chain, branched or cycloalkoxy groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkoxy group in formula (11) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0384] Examples of the aralkyl group in formula (11) include aralkyl groups having 7 to 20 (preferably 7 to 15, more preferably 7 to 12) carbon atoms, and specific examples thereof include benzyl and phenethyl. The aralkyl group in formula (11) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group, and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom).

[0385] Examples of the aryl group in formula (11) include aryl groups having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms, and specific examples thereof include phenyl, biphenyl, 1-naphthyl and 2-naphthyl. The aryl group in formula (11) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0386] Examples of the aryloxy group in formula (11) include aryloxy groups having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms, and specific examples thereof include phenoxy, biphenyloxy, 1-naphthyloxy and 2-naphthyloxy. The aryloxy group in formula (11) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0387] In formula (11), n1 and n2 each independently represent an integer of 0 to 5, preferably an integer of 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0388] Acceptor compounds (11-1) to (11-10) are shown below as specific examples of the compound represented by the formula (11), but the examples are not limited thereto.

[0389]

[0390] In formula (12), R 121 and R 122 Each independently represents a halogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, a nitro group, a carboxyl group or a hydroxyl group, and n1 and n2 each independently represent an integer of 0 to 5.

[0391] When n1 is 2 or more, multiple R 121 May be the same as or different from each other.

[0392] When n2 is 2 or more, the presence of multiple R 122May be the same as or different from each other.

[0393] Examples of the halogen atom in the formula (12) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0394] Examples of the alkyl group in formula (12) include linear, branched or cyclic alkyl groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkyl group in formula (12) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0395] Examples of the alkoxy group in formula (12) include straight chain, branched or cycloalkoxy groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkoxy group in formula (12) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0396] Examples of the aralkyl group in formula (12) include aralkyl groups having 7 to 20 (preferably 7 to 15, more preferably 7 to 12) carbon atoms, and specific examples thereof include benzyl and phenethyl. The aralkyl group in formula (12) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group, and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom).

[0397] Examples of the aryl group in formula (12) include aryl groups having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms, and specific examples thereof include phenyl, biphenyl, 1-naphthyl and 2-naphthyl. The aryl group in formula (12) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0398] Examples of the aryloxy group in formula (12) include aryloxy groups having 6 to 20 (preferably 6 to 14, more preferably 6 to 12) carbon atoms, and specific examples thereof include phenoxy, biphenyloxy, 1-naphthyloxy and 2-naphthyloxy. The aryloxy group in formula (12) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group, a nitro group, an alkyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0399] In formula (12), n1 and n2 each independently represent an integer of 0 to 5, preferably an integer of 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0400] Acceptor compounds (12-1) to (12-10) are shown below as specific examples of the compound represented by formula (12), but the examples are not limited thereto.

[0401]

[0402] In formula (13), R 131 , R 132 , R 133 , R 134 , R 135 , R 136 , R 137 and R 138 Each independently represents a hydrogen atom, a halogen atom, an alkyl group, a carboxyl group or a hydroxyl group.

[0403] Examples of the halogen atom in the formula (13) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0404] Examples of the alkyl group in formula (13) include a linear, branched or cyclic alkyl group having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkyl group in formula (13) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0405] In formula (13), R 131 and R 134 Each is preferably a hydrogen atom, a halogen atom, an alkyl group or a hydroxyl group, more preferably a hydrogen atom or a halogen atom, still more preferably a hydrogen atom.

[0406] In formula (13), R 132 and R 133 Each is preferably a hydrogen atom, an alkyl group, a carboxyl group or a hydroxyl group.

[0407] In formula (13), R 135 and R 138 Each is preferably a hydrogen atom, an alkyl group, a carboxyl group or a hydroxyl group.

[0408] In formula (13), R 136 and R 137 Each is preferably a hydrogen atom, a halogen atom or an alkyl group, more preferably a hydrogen atom or a halogen atom, still more preferably a hydrogen atom.

[0409] Acceptor compounds (13-1) to (13-10) are shown below as specific examples of the compound represented by formula (13), but the examples are not limited thereto.

[0410]

[0411]

[0412] In formula (14), R 141 , R 142 , R 143 , R 144 , R 145 , R 146 , R 147 , R 148, R 149 and R 150 Each independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a carboxyl group or a hydroxyl group, provided that R 141 , R 142 , R 143 , R 144 , R 145 , R 146 , R 147 , R 148 , R 149 and R 150 At least one of represents a carboxyl group.

[0413] Examples of the halogen atom in the formula (14) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0414] Examples of the alkyl group in formula (14) include a linear, branched or cyclic alkyl group having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkyl group in formula (14) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0415] Examples of the alkoxy group in formula (14) include linear, branched or cyclic alkoxy groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. The alkoxy group in formula (14) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0416] The compound represented by formula (14) has at least one carboxyl group in the molecule. The number of carboxyl groups in the compound represented by formula (14) is preferably 1 to 4 per molecule, more preferably 1 or 2. The carboxyl group in the compound represented by formula (14) is preferably R 142 , R 143 , R 147 or R 148 , more preferably R 142 or R 147 .

[0417] Acceptor compounds (14-1) to (14-10) are shown below as specific examples of the compound represented by formula (14), but the examples are not limited thereto.

[0418]

[0419] In formula (15), R 151 , R 152 , R 153 , R 154 , R 155 , R 156 , R 157 , R 158 , R159 and R 160 Each independently represents a hydrogen atom, a halogen atom, an alkyl group, a carboxyl group or a hydroxyl group, and adjacent groups may be linked to each other to form a ring, provided that R 151 , R 152 , R 153 , R 154 , R 155 , R 156 , R 157 , R 158 , R 159 and R 160 At least one of represents a carboxyl group or a hydroxyl group.

[0420] In the case where adjacent groups in formula (15) are connected to each other to form a ring, examples of the structure of the formed ring include aromatic rings and alicyclic rings, and specific examples include benzene, naphthalene, phenanthrene, cyclopentane, cyclohexane, cycloheptane, 3,5-dimethylcyclohexane, 3,5-diethylcyclohexane, 3,5-diisopropylcyclohexane, 3,3,5-trimethylcyclohexane and 3,3,5,5-tetramethylcyclohexane.

[0421] Examples of the halogen atom in the formula (15) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0422] Examples of the alkyl group in formula (15) include straight chain, branched or cyclic alkyl groups having 1 to 10 (preferably 1 to 6, more preferably 1 to 4) carbon atoms. Among these, methyl, ethyl, n-propyl, isopropyl and cyclohexyl are preferred. The alkyl group in formula (15) may also be substituted with a substituent such as a hydroxyl group, a carboxyl group and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom).

[0423] The compound represented by formula (15) has at least one carboxyl group or hydroxyl group in the molecule. The number of carboxyl groups or hydroxyl groups in the compound represented by formula (15) is preferably 1 to 4 in total, more preferably 1 or 2 per molecule.

[0424] The carboxyl group or hydroxyl group in the compound represented by formula (15) is preferably 153 , R 154 , R 158 or R 159 , more preferably R 154 or R 159 .

[0425] Acceptor compounds (15-1) to (15-10) are shown below as specific examples of the compound represented by formula (15), but the examples are not limited thereto.

[0426]

[0427] Specific examples of the alkyl group and the alkoxy group in formulas (3), (4), (5), (6), (7), (8), (9), (10), (11), (12), (13), (14) and (15) include the following groups.

[0428] Examples of straight-chain alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl and n-decyl.

[0429] Examples of branched alkyl groups include isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, isohexyl, sec-hexyl, tert-hexyl, isoheptyl, sec-heptyl, tert-heptyl, isooctyl, sec-octyl, tert-octyl, isononyl, sec-nonyl, tert-nonyl, isodecyl, sec-decyl and tert-decyl.

[0430] Examples of the cycloalkyl group include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl, and polycyclic (eg, bicyclic, tricyclic or spirocyclic) alkyl groups formed by linking these monocyclic alkyl groups.

[0431] Examples of straight-chain alkoxy groups include methoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, n-hexoxy, n-heptyloxy, n-octyloxy, n-nonyloxy and n-decyloxy.

[0432] Examples of branched alkoxy groups include isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentyloxy, neopentyloxy, tert-pentyloxy, isohexyloxy, sec-hexyloxy, tert-hexyloxy, isoheptyloxy, sec-heptyloxy, tert-heptyloxy, isooctyloxy, sec-octyloxy, tert-octyloxy, isononyloxy, sec-nonyloxy, tert-nonyloxy, isodecyloxy, sec-decyloxy and tert-decyloxy.

[0433] Examples of cycloalkoxy groups include cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, cyclohexyloxy, cycloheptyloxy, cyclooctyloxy, cyclononyloxy and cyclodecyloxy.

[0434] From the viewpoint of easily accepting electrons from the compound represented by formula (1) or the compound represented by formula (2), the acceptor compound is preferably a compound represented by formula (6), a compound represented by formula (13), a compound represented by formula (14) or a compound represented by formula (15).

[0435] From the viewpoint of preventing deterioration of photosensitivity when repeatedly forming images, the total content of the acceptor compound contained in the undercoat layer is preferably 2% by weight to 30% by weight, more preferably 5% by weight to 25% by weight, and even more preferably 10% by weight to 20% by weight, relative to the total content of the compound represented by formula (1) and the compound represented by formula (2) contained in the undercoat layer.

[0436] From the viewpoint of preventing deterioration of photosensitivity when repeatedly forming images, the total content of the acceptor compound contained in the undercoat layer is preferably 1 wt % to 25 wt %, more preferably 5 wt % to 20 wt %, and even more preferably 10 wt % to 15 wt % relative to the total solid content of the undercoat layer.

[0437] Examples of the binder resin for the undercoat layer include known materials, including known polymer compounds such as acetal resins (e.g., polyvinyl butyral), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, unsaturated polyester resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, urea resins, phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, alkyd resins, and epoxy resins; zirconium chelate compounds; titanium chelate compounds; aluminum chelate compounds; alkoxytitanium compounds; organic titanium compounds; and silane coupling agents.

[0438] Examples of the binder resin used for the undercoat layer also include a charge transporting resin having a charge transporting group and a conductive resin such as polyaniline.

[0439] Among these, as the binder resin for the primer layer, a resin that is insoluble in the coating solvent for the upper layer is preferred. In particular, thermosetting resins (such as urea resins, phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, unsaturated polyester resins, alkyd resins and epoxy resins), resins obtained by reaction between at least one selected from the group consisting of polyamide resins, polyester resins, polyether resins, methacrylic resins, acrylic resins, polyvinyl alcohol resins and polyvinyl acetal resins and a curing agent are preferred.

[0440] In the case of using two or more of these binder resins in combination, the mixing ratio thereof is set as needed.

[0441] In the case where the undercoat layer contains inorganic particles, examples of the inorganic particles include those having 1×10 2 (Ω·cm)~1×10 11 Inorganic particles with a powder resistance (volume resistivity) of (Ω·cm).

[0442] Among these, examples of the inorganic particles having the above resistance value may be metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, and zirconium oxide particles, and zinc oxide particles are particularly preferred.

[0443] The BET specific surface area of ​​the inorganic particles can be, for example, 10 m 2 / g or above.

[0444] The volume average particle diameter of the inorganic particles may be, for example, 50 nm to 2,000 nm (more preferably 60 nm to 1,000 nm).

[0445] The content of the inorganic particles is, for example, preferably 10% by weight to 80% by weight, and more preferably 40% by weight to 80% by weight, based on the binder resin.

[0446] The inorganic particles may be surface treated. Two or more inorganic particles having different surface treatments or different particle sizes may be mixed and used.

[0447] Examples of the surface treatment agent include silane coupling agents, titanate coupling agents, aluminum coupling agents, and surfactants. In particular, silane coupling agents are preferred.

[0448] The undercoat layer may contain various additives to improve electrical properties, environmental stability, and image quality.

[0449] Examples of additives include known materials such as electron transport pigments (such as polycyclic condensed type and azo type), zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, alkoxytitanium compounds, organic titanium compounds and silane coupling agents. The silane coupling agent is used for the surface treatment of the metal oxide particles as described above, but can be further added to the primer as an additive.

[0450] Examples of the silane coupling agent as the additive include vinyltrimethoxysilane, 3-methacryloxypropyl-tri(2-methoxyethoxy)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane.

[0451] Examples of the zirconium chelate compound include zirconium butoxide, zirconium ethyl acetoacetate, zirconium acetylacetonate butoxy, zirconium ethyl acetoacetate butoxy, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octanoate, zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, zirconium methacrylate butoxy, zirconium stearate butoxy, and zirconium isostearate butoxy.

[0452] 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, titanium ammonium lactate, titanium lactate, titanium ethyl lactate, and polyhydroxytitanium stearate.

[0453] Examples of the aluminum chelate compound include aluminum isopropoxide, monobutoxyaluminum diisopropoxide, aluminum butyrate, diethyl acetoacetate aluminum diisopropoxide, and tris(ethyl acetoacetate)aluminum.

[0454] These additives may be used alone or as a mixture or polycondensate of a plurality of compounds.

[0455] The primer layer preferably has a Vickers hardness of 35 or more.

[0456] In order to prevent moiré fringes, the surface roughness (ten-point average roughness) of the undercoat layer may be adjusted to 1 / (4n) (n is the refractive index of the upper layer) to 1 / 2 of the exposure laser wavelength λ.

[0457] 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 polymethyl methacrylate resin particles. Furthermore, in order to adjust the surface roughness, the surface of the undercoat layer may be polished. Examples of the polishing method include buffing, sandblasting, wet honing, and grinding.

[0458] The formation of the undercoat layer is not particularly limited, and a known formation method can be used. For example, a coating film of an undercoat layer-forming coating liquid obtained by adding the above-mentioned components to a solvent is formed, and the coating film is dried by heating as necessary to form the undercoat layer.

[0459] 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.

[0460] Specific examples of these solvents include common organic solvents such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, dichloromethane, chloroform, chlorobenzene and toluene.

[0461] Examples of a dispersion method of the inorganic particles in preparing the undercoat layer-forming coating liquid 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.

[0462] Examples of a method for applying the undercoat layer-forming coating liquid onto the conductive substrate include general methods such as knife coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0463] The thickness of the undercoat layer is preferably 5 μm to 50 μm, more preferably 10 μm to 40 μm, and still more preferably 15 μm to 30 μm.

[0464] The volume resistivity of the primer layer is preferably 1×10 4 Ω·m~1×10 8 Ω·m.

[0465] Hereinafter, the undercoat layer of the third electrophotographic photoreceptor will be described in detail. The description is provided without using reference numerals.

[0466] [Base coating]

[0467] (Binder resin comprising a resin obtained by polymerizing a diallyl phthalate compound)

[0468] The binder resin includes a resin obtained by polymerizing a diallyl phthalate compound.

[0469] The diallyl phthalate compound refers to a compound having a diallyl phthalate skeleton.

[0470] Examples of the compound having a diallyl phthalate skeleton include diallyl o-phthalate, diallyl isophthalate (diallyl isophthalate), and diallyl p-terephthalate.

[0471] Among the compounds having a diallyl phthalate skeleton, the diallyl phthalate compound preferably includes a diallyl isophthalate compound.

[0472] If the diallyl phthalate compound includes a diallyl isophthalate compound, when the diallyl isophthalate compound is polymerized to prepare the binder resin, it is easy to prevent intermolecular crosslinking. Therefore, the binder resin tends to be preferentially generated by intermolecular polymerization, and the undercoat layer tends to be formed in a state where the charge transport material is highly dispersed in the diallyl phthalate compound solution. As a result, the charge transport efficiency is improved, and the rise of the residual potential when forming repeated images tends to be prevented.

[0473] Examples of the diallyl phthalate compound include monomers of a compound having a diallyl phthalate skeleton, prepolymers composed of one or more monomers of a compound having a diallyl phthalate skeleton, and mixtures thereof.

[0474] Among the above examples, the diallyl phthalate compound preferably includes a monomer and a prepolymer of the diallyl phthalate compound.

[0475] When the diallyl phthalate compound includes a monomer and a prepolymer of the diallyl phthalate compound, the curing degree of the binder resin, the solubility of the binder resin in an organic solvent, the film thickness of the charge generating layer, and the like tend to be easily controlled.

[0476] The weight average molecular weight (Mw) of the prepolymer is preferably 200,000 or less, more preferably 100,000 or less, and still more preferably 50,000 or less.

[0477] When the weight average molecular weight of the prepolymer is 200,000 or less, the film strength in the undercoat layer tends to improve while maintaining the dispersibility of the charge transport material.

[0478] The weight average molecular weight of the prepolymer is a value measured by using gel permeation chromatography (GPC). The molecular weight measurement using GPC is carried out, for example, using GPC HLC-8120 (manufactured by Tosoh Corporation) and column TSKgel GMHHR-M + TSKgelGMHHR-M (7.8 mm ID, 30 cm) (manufactured by Tosoh Corporation) as a measuring device using a chloroform solvent. From the measurement results, the molecular weight is calculated by using a molecular weight calibration curve prepared by using a monodisperse polystyrene standard sample.

[0479] In the case of using a monomer and a prepolymer in combination, the weight ratio of the monomer and the prepolymer is preferably 1 / 99 to 99 / 1, more preferably 80 / 20 to 20 / 80.

[0480] As long as the residual potential can be prevented from increasing when repeated images are formed, the binder resin may be a binder resin obtained by polymerizing a diallyl phthalate compound and a curable compound other than the diallyl phthalate compound.

[0481] Examples of curable compounds other than the diallyl phthalate compound include styrene monomers, (meth)acrylic monomers, polymers thereof, or mixtures thereof. The expression "(meth)acrylic" in the present specification includes "acrylic" and "methacrylic".

[0482] Examples of styrene monomers include styrene, alkyl-substituted styrenes (such as α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene and 4-ethylstyrene), halogen-substituted styrenes (such as 2-chlorostyrene, 3-chlorostyrene and 4-chlorostyrene) and vinylnaphthalene. Among these, as a styrene monomer, styrene is preferred from the viewpoints of easiness of reaction, easiness of reaction control and availability. One styrene monomer may be used alone, or two or more thereof may be used in combination.

[0483] Examples of (meth)acrylic monomers include (meth)acrylic acid and (meth)acrylic acid esters. Examples of (meth)acrylic acid esters include alkyl (meth)acrylic acid esters (such as methyl (meth)acrylic acid ester, ethyl (meth)acrylic acid ester, n-propyl (meth)acrylic acid ester, n-butyl (meth)acrylic acid ester, n-pentyl (meth)acrylic acid ester, n-hexyl (meth)acrylic acid ester, n-heptyl (meth)acrylic acid ester, n-octyl (meth)acrylic acid ester, n-decyl (meth)acrylic acid ester, n-dodecyl (meth)acrylic acid ester, n-lauryl (meth)acrylic acid ester, n-tetradecyl (meth)acrylic acid ester, n-hexadecyl (meth)acrylic acid ester, n-octadecyl (meth)acrylic acid ester, isopropyl (meth)acrylic acid ester, isobutyl (meth)acrylic acid ester, The (meth)acrylic acid monomer is preferably tert-butyl (meth)acrylate, isopentyl (meth)acrylate, neopentyl (meth)acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, and tert-butylcyclohexyl (meth)acrylate), aryl (meth)acrylate (such as phenyl (meth)acrylate, biphenyl (meth)acrylate, diphenylethyl (meth)acrylate, tert-butylphenyl (meth)acrylate, and terphenyl (meth)acrylate), methoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and β-carboxyethyl (meth)acrylate. From the viewpoint of fixability, the (meth)acrylic acid monomer is preferably a (meth)acrylic acid ester having 2 to 14 (preferably 2 to 10, and more preferably 3 to 8) carbon atoms. One (meth)acrylic acid monomer may be used alone, or two or more thereof may be used in combination.

[0484] In the case where the binder resin contains a curable compound other than the diallyl phthalate compound, the binder resin may be a binder resin obtained by polymerizing the diallyl phthalate compound and a (meth)acrylic monomer.

[0485] When the binder resin is a binder resin obtained by polymerizing a diallyl phthalate compound and a (meth) acrylic monomer, the film strength of the undercoat layer tends to be improved. When the film strength of the undercoat layer is high, for example, in the case where a needle-shaped foreign matter such as carbon fiber is contained in the toner, even if the needle-shaped foreign matter causes cracks to occur in the electrophotographic photoreceptor, the cracks tend to be difficult to occur in the undercoat layer. As a result, leakage current is easily prevented.

[0486] When the binder resin contains a curable compound other than the diallyl phthalate compound, the content of the diallyl phthalate compound is preferably 50 to 99.5 parts by weight, more preferably 80 to 99.5 parts by weight, based on 100 parts by weight of the total solid content of the binder resin.

[0487] Examples of the polymerization initiator used when polymerizing the diallyl phthalate compound include a thermal polymerization initiator and a photopolymerization initiator, and a known polymerization initiator may be applied depending on the selected diallyl phthalate compound or the thickness of the undercoat layer.

[0488] Examples of the thermal polymerization initiator include dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butylcumyl peroxide, di-tert-butyl peroxide, di(4-tert-butylcyclohexyl)percarbonate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, tert-hexylperoxy-2-ethylhexanoate, tert-butyl ... Hexyl peroxyisopropyl monocarbonate, tert-butyl peroxymaleic acid, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxylaurate, 2,5-dimethyl-2,5-di(m-tolylperoxy)hexane, tert-butyl peroxyisopropyl monocarbonate, tert-butyl peroxy-2-ethylhexyl monocarbonate, tert-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, tert-butyl peroxym-tolylbenzoate, tert-butyl peroxybenzoate and di(tert-butylperoxy)isophthalate.

[0489] Examples of the photopolymerization initiator include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, and 2,4-diisopropylthioxanthone.

[0490] In the case where a thermal polymerization initiator is used as the polymerization initiator, the temperature at which the diallyl phthalate compound is polymerized and cured is preferably room temperature (23°C) to 300°C, more preferably 100°C to 250°C, still more preferably 150°C to 200°C.

[0491] The atmosphere for polymerizing and curing the diallyl phthalate compound is not particularly limited, and may be an air atmosphere or a nitrogen atmosphere.

[0492] When the temperature of polymerizing and curing the diallyl phthalate compound is room temperature or above, the curing rate can be prevented from decreasing, and a cured film tends to be effectively formed. On the other hand, when the temperature of polymerizing and curing the diallyl phthalate compound is 300° C. or below, oxidative decomposition or coloring of the charge transport material can be easily prevented.

[0493] In the binder resin, the mixing ratio of the polymerization initiator and the diallyl phthalate compound (polymerization initiator / diallyl phthalate compound) is preferably 1 / 100 to 1 / 1, and more preferably 3 / 100 to 3 / 10.

[0494] When the mixing amount of the polymerization initiator is 1 / 100 or more of the mixing amount of the diallyl phthalate compound, it is easy to prevent the formation of residues of the unreacted diallyl phthalate compound. On the other hand, when the mixing amount of the polymerization initiator is 1 / 1 or less of the mixing amount of the diallyl phthalate compound, it is easy to prevent the decomposition of the charge transport material and the deterioration of the electrical properties caused by the excess polymerization initiator remaining in the binder resin.

[0495] The weight loss of the resin obtained by polymerizing the diallyl phthalate compound after extracting the resin obtained by polymerizing the diallyl phthalate compound with hot acetone (hereinafter referred to as "extraction weight loss") is preferably 20% by weight or less, more preferably 15% by weight or less, and still more preferably 10% by weight or less, relative to the total amount of the resin obtained by polymerizing the diallyl phthalate compound before extraction with hot acetone.

[0496] When the extracted weight loss of the resin obtained by polymerizing the diallyl phthalate compound is 20% by weight or less, the dispersibility of the charge transport material in the undercoat layer tends to increase, and the film strength of the undercoat layer tends to improve.

[0497] The extraction weight loss of the resin obtained by polymerizing the diallyl phthalate compound is measured as follows.

[0498] (1) A layer (such as a photosensitive layer) formed on the outer peripheral surface of the undercoat layer in the electrophotographic photoreceptor is removed by removal with a cutter or by dissolution with a solvent or the like.

[0499] (2) The undercoat layer is cut, and the resultant is dissolved in a solvent or the like or filtered to remove the charge transporting material, thereby isolating the resin obtained by polymerizing the diallyl phthalate compound.

[0500] (3) Finely pulverize the resin obtained by polymerizing diallyl phthalate compound and separated from the undercoat layer with a mortar or the like, weigh a certain amount thereof, and put it into a cylindrical filter paper. Next, the cylindrical filter paper containing the resin obtained by polymerizing diallyl phthalate compound is placed in a Soxhlet extractor and refluxed with acetone for 2 hours to extract the resin. Afterwards, the cylindrical filter paper is dried under reduced pressure and further dried by standing in the atmosphere for 1 hour. The weight of the cylindrical filter paper containing the resin is weighed, and the value obtained by deducting the filter paper weight from the obtained weight is taken as the extraction weight loss of the resin obtained by polymerizing diallyl phthalate compound.

[0501] The binder resin may contain other resins than the resin obtained by polymerizing the diallyl phthalate compound as long as the effects of the exemplary embodiment are not impaired.

[0502] Examples of other resins include polycarbonate resins (such as bisphenol A and bisphenol Z), olefin resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polystyrene resins, polyvinyl acetate resins, styrene-butadiene copolymer resins, vinylidene chloride-acrylonitrile copolymer resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, phenol-formaldehyde resins, styrene-alkyd resins, and poly-N-vinyl carbazole. One of these binder resins can be used alone, or two or more thereof can be used in combination. In this case, from the viewpoint of achieving the effect of the exemplary embodiment, the content of the resin obtained by polymerizing the diallyl phthalate compound is preferably 90% by weight or more (more preferably 95% or more) relative to the total amount of the binder resin contained in the primer layer.

[0503] (Charge Transport Material)

[0504] The undercoat layer contains a charge transport material.

[0505] Examples of the charge transport material include electron transport materials and hole transport materials.

[0506] Examples of electron transport materials include: electron transport compounds such as pyrenone compounds, quinone compounds (such as p-benzoquinone, chloranil, bromoquinone and anthraquinone); tetracyanoquinodimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone; xanthone compounds; benzophenone compounds; cyanovinyl compounds; vinyl compounds; and 9-dicyanomethylenefluorene compounds.

[0507] These electron transport materials may be used alone or in combination of two or more, but are not limited thereto.

[0508] Examples of the hole transporting material include hole transporting compounds such as benzidine compounds, aryl alkane compounds, aryl substituted vinyl compounds, stilbene compounds, anthracene compounds, and hydrazone compounds.

[0509] These hole transport materials may be used alone or in combination of two or more, but are not limited thereto.

[0510] Among the above compounds, the charge transport material preferably contains at least one pyrenone compound represented by formula (1) and (2) from the viewpoint of preventing an increase in residual potential when repeated images are formed.

[0511] The compound represented by formula (1) and the compound represented by formula (2) are the same as the compound represented by formula (1) and the compound represented by formula (2) in the first photoreceptor described above. The description of the compound represented by formula (1) and the compound represented by formula (2) in the first photoreceptor described above can also be applied to the compound represented by formula (1) and the compound represented by formula (2) in the third photoreceptor.

[0512] From the viewpoint of preventing the residual potential from increasing when repeated images are formed, it is preferred that R in the formula (1) 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 Each independently represents a hydrogen atom, an alkyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group or an aryloxycarbonylalkyl group, and R in formula (2) 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 and R 28 Each independently represents a hydrogen atom, an alkyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group or an aryloxycarbonylalkyl group.

[0513] The ratio of the pyrenone compounds represented by formulae (1) and (2) to the charge transport material is preferably 90% by weight to 100% by weight, more preferably 98% by weight to 100% by weight.

[0514] The content of the charge transport material is preferably 20 to 80 wt % relative to the total solid content of the undercoat layer from the viewpoint of preventing an increase in residual potential when forming repeated images, and more preferably 40 to 80 wt % from the viewpoint of film uniformity during coating.

[0515] (Inorganic particles)

[0516] The undercoat layer may further contain inorganic particles.

[0517] Examples of inorganic particles include those having a powder resistance (volume resistivity) of 1.0×10 2 (Ω·cm)~1.0×10 11 (Ω·cm) of inorganic particles.

[0518] Examples of inorganic particles having such resistance values ​​include metal oxide particles of zinc oxide, titanium oxide, tin oxide, aluminum oxide, indium oxide, silicon dioxide, magnesium oxide, barium oxide, or molybdenum oxide, etc. These may be used alone or in combination of two or more thereof.

[0519] Among the above particles, at least one or more selected from the group consisting of zinc oxide, titanium oxide, and tin oxide are preferred as the metal oxide particles from the viewpoint of preventing an increase in residual potential when outputting repeated images.

[0520] The BET specific surface area of ​​the inorganic particles is preferably, for example, 10 m2 / g or more. The BET specific surface area is measured using a nitrogen replacement method. Specifically, the BET specific surface area is measured by a three-point method using a SA3100 specific surface area measurement device (manufactured by Beckman Coulter, Inc.).

[0521] The volume average particle diameter of the inorganic particles is preferably, for example, 50 nm to 2,000 nm (more preferably 60 nm to 1,000 nm).

[0522] The volume average particle size is measured using a laser diffraction type particle size distribution measuring device (LA-700: manufactured by Horiba, Ltd.). As a measuring method, 2 g of a measurement sample is added to 50 mL of a 5% surfactant (preferably sodium alkylbenzene sulfonate) aqueous solution and dispersed with an ultrasonic disperser for 2 minutes (1,000 Hz) to prepare a sample, and the sample is measured. The volume average particle size of each resulting channel is accumulated from the smaller value of the volume average particle size, and the point at which the accumulation reaches 50% is taken as the volume average particle size.

[0523] From the viewpoint of preventing an increase in residual potential when outputting repeated images, the content of the inorganic particles (specifically, metal oxide particles) in the undercoat layer is preferably 10 to 80% by weight, more preferably 20 to 70% by weight.

[0524] The inorganic particles may be surface treated. Two or more inorganic particles having different surface treatments or different particle sizes may be mixed and used.

[0525] Examples of the surface treatment agent include silane coupling agents, titanate coupling agents, aluminum coupling agents, and surfactants. In particular, silane coupling agents are preferred.

[0526] Two or more silane coupling agents may be used in combination.

[0527] Examples of the silane coupling agent include vinyltrimethoxysilane, 3-methacryloxypropyl-tri(2-methoxyethoxy)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane, but are not limited thereto.

[0528] The surface treatment method using the surface treatment agent may be any method as long as it is a known method, and a dry method or a wet method may be used.

[0529] From the viewpoint of improving dispersibility, the amount of the surface treatment agent used for the treatment is preferably 0.5% by weight to 10% by weight relative to the inorganic particles.

[0530] From the viewpoint of improving the long-term stability of electrical characteristics and carrier blocking properties, the undercoat layer may further contain an electron accepting compound (acceptor compound) together with the inorganic particles.

[0531] Examples of electron accepting compounds include: electron transporting substances, such as: quinone compounds (such as chloranil and bromoquinone); tetracyanoquinodimethane compounds; fluorenone compounds, such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone; oxadiazole compounds, such as 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole and 2,5-di(4-naphthyl)-1,3,4-oxadiazole; xanthone compounds; thiophene compounds; and diphenoquinone compounds, such as 3,3',5,5'-tetra-tert-butyldiphenoquinone.

[0532] In particular, as the electron accepting compound, a compound having an anthraquinone structure is preferred. As the compound having an anthraquinone structure, for example, a hydroxyanthraquinone compound is preferred. Specifically, for example, anthraquinone, alizarin, quinizarin, anthrarufine, and purpurin are preferred.

[0533] The electron accepting compound may be contained in the undercoat layer by being dispersed together with the inorganic particles, or may be contained in a state of being attached to the surface of the inorganic particles.

[0534] Examples of a method for attaching the electron accepting compound to the surface of the inorganic particles include a dry method or a wet method.

[0535] The dry method is, for example, a method in which inorganic particles are stirred using a mixer having a large shear force, an electron accepting compound is directly dripped, an electron accepting compound dissolved in an organic solvent is dripped, or the electron accepting compound is sprayed onto the stirred inorganic particles together with dry air or nitrogen, thereby attaching the electron accepting compound to the surface of the inorganic particles. When the electron accepting compound is dripped or sprayed, the dripping or spraying of the electron accepting compound can be carried out at a temperature equal to or lower than the boiling point of the solvent. After the dripping or spraying of the electron accepting compound, baking can be further carried out at more than 100°C. Baking is not specifically limited, as long as baking is carried out at a temperature and time that obtains electrophotographic properties.

[0536] The wet method is a method including, for example, the following steps: dispersing the inorganic particles in a solvent by stirring with an ultrasonic wave, a sand mill, a grinder or a ball mill, adding an electron accepting compound thereto, stirring or dispersing the resultant, and then removing the solvent so that the electron accepting compound is attached to the surface of the inorganic particles. In the solvent removal method, the solvent is removed, for example, by filtering or distillation. After the solvent is removed, baking is further performed at 100°C or above. Baking is not specifically limited as long as baking is performed at a temperature and time for obtaining electrophotographic characteristics. In the wet method, the moisture contained in the inorganic particles can be removed before adding the electron accepting compound. Examples of this method include a method of removing moisture while stirring and heating in a solvent and a method of removing moisture by azeotropic distillation with a solvent.

[0537] The attachment of the electron accepting compound may be performed before or after the surface treatment of the inorganic particles with the surface treatment agent. Alternatively, the attachment of the electron accepting compound and the surface treatment with the surface treatment agent may be performed simultaneously.

[0538] The content of the electron accepting compound may be, for example, 0.01% by weight to 20% by weight, and preferably 0.01% by weight to 10% by weight, based on the inorganic particles.

[0539] (Additives for primer coating)

[0540] The undercoat layer may further contain various additives.

[0541] As the additive, for example, binder resin particles may be added. Examples of the binder resin particles include known materials such as silicone binder resin particles and cross-linked polymethyl methacrylate (PMMA) binder resin particles.

[0542] (Properties of the base coating)

[0543] Hereinafter, other properties of the primer layer are described.

[0544] From the viewpoint of preventing an increase in residual potential when repeated images are formed, the thickness of the undercoat layer is preferably 3 μm to 50 μm, more preferably 3 μm to 30 μm, and even more preferably 3 μm to 20 μm.

[0545] The film thickness of the undercoat layer was measured using an eddy current film thickness meter CTR-1500E manufactured by Sanko Denshi Co., Ltd.

[0546] From the viewpoint of preventing the residual potential from increasing when repeated images are formed, the volume resistivity of the undercoat layer is preferably 1.0×10 4 (Ω·m)~10×10 10 (Ω·m), more preferably 1.0×10 6 (Ω·m)~10×108 (Ω·m), and more preferably 1.0×10 6 (Ω·m)~10×10 7 (Ω·m).

[0547] The method for preparing the undercoat layer sample for measuring the volume resistivity from the electrophotographic photoreceptor is as follows. For example, a coating film such as a charge generating layer and a charge transporting layer covering the undercoat layer is removed using a solvent such as acetone, tetrahydrofuran, methanol or ethanol, and a gold electrode is attached to the exposed undercoat layer by a vacuum deposition method or a sputtering method to obtain the undercoat layer sample for measuring the volume resistivity.

[0548] For the measurement of volume resistivity by the AC impedance method, SI 1287 electrochemical interface (manufactured by TOYO Corporation) was used as a power source, SI 1260 impedance / gain phase analyzer (manufactured by TOYO Corporation) was used as an ammeter, and 1296 dielectric interface (manufactured by Toyo Corporation) was used as a current amplifier.

[0549] Using the AC impedance measurement sample with the aluminum substrate as the cathode and the gold electrode as the anode, an AC voltage of 1 Vp-p was applied from the high frequency side in a frequency range of 1 MHz to 1 mHz, and the AC impedance of each sample was measured to calculate the volume resistivity by fitting the measured Cole-Cole plot to an RC parallel equivalent circuit.

[0550] The primer layer preferably has a Vickers hardness of 35 or more.

[0551] In order to prevent moiré fringes, the surface roughness (ten-point average roughness) of the undercoat layer may be adjusted to 1 / (4n) (n is the refractive index of the upper layer) to 1 / 2 of the exposure laser wavelength λ.

[0552] In order to adjust the surface roughness, adhesive resin particles and the like can be added to the primer. Examples of adhesive resin particles include silicone adhesive resin particles and cross-linked polymethyl methacrylate adhesive resin particles. In addition, in order to adjust the surface roughness, the surface of the primer can be polished. Examples of polishing methods include buffing, sandblasting, wet honing and grinding.

[0553] The method for forming the undercoat layer is not particularly limited, and a known formation method can be used. For example, a coating film of an undercoat layer-forming coating liquid obtained by adding the above components to a solvent is formed, and the coating film can be dried and heated as necessary to form the undercoat layer.

[0554] Examples of the method for dispersing the charge transport material (when inorganic particles, the charge transport material and the inorganic particles are also contained) when preparing the coating liquid for forming the 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.

[0555] Examples of a method for applying the undercoat layer-forming coating liquid onto the conductive substrate include common methods such as knife coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0556] [Conductive substrate]

[0557] Hereinafter, the conductive substrate in each of the first to third photoreceptors will be described.

[0558] Examples of the conductive substrate include metal plates, metal drums, and metal belts containing metals (such as aluminum, copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold, and platinum) or alloys (such as stainless steel). In addition, examples of the conductive substrate also include paper, resin films, and belts obtained by coating, vapor deposition, or lamination of conductive compounds (such as conductive polymers or indium oxide, etc.), metals (such as aluminum, palladium, or gold, etc.), or alloys. Here, "conductive" means that the volume resistivity is less than 1×10 13 Ω·cm.

[0559] In the case where the electrophotographic photoreceptor is used in a laser printer, the surface of the conductive substrate is preferably roughened to a center line average roughness Ra of 0.04 μm to 0.5 μm to prevent interference fringes when emitting laser light. In the case of using non-interference light as a light source, although roughening for preventing interference fringes is not particularly necessary, it is suitable for a longer life because roughening can prevent defects due to irregularities on the surface of the conductive substrate.

[0560] Examples of the surface roughening method include wet honing performed by suspending an abrasive in water and blowing the suspension onto the conductive substrate, centerless grinding performed by pressing the conductive substrate against a rotating grinding wheel and performing a continuous grinding process, and anodizing.

[0561] Examples of the surface roughening method also include a method in which a conductive or semiconductive powder is dispersed in a resin to form a layer on the surface of a conductive base without roughening the surface of the conductive base, and the surface roughening is performed by particles dispersed in the layer.

[0562] The surface roughening treatment performed by anodization forms an oxide film on the surface of the conductive substrate by using a metal (e.g., aluminum) conductive substrate as an anode to perform anodization in an electrolyte. The example of the electrolyte includes sulfuric acid solution and oxalic acid solution. However, the porous anodized film formed by anodization is chemically active in the original state, easily contaminated, and has a large resistance change depending on the environment. Therefore, the porous anodized film is preferably sealed (the pores of the oxide film are closed by the volume expansion caused by the hydration reaction in pressurized water vapor or boiling water (metal salts such as nickel can be added), thereby becoming a more stable hydrated oxide).

[0563] The thickness of the anodized film is preferably, for example, 0.3 μm to 15 μm. When the film thickness is within the above range, there is a tendency to exhibit a barrier property against injection, and there is a tendency to prevent the residual potential from increasing due to repeated use.

[0564] The conductive substrate may also be treated with an acid treatment solution or subjected to a boehmite treatment.

[0565] The treatment with the acid treatment solution is carried out, for example, as follows. First, an acid treatment solution containing phosphoric acid, chromic acid and hydrofluoric acid is prepared. The mixing ratio of phosphoric acid, chromic acid and hydrofluoric acid in the acid treatment solution is, for example, 10% to 11% by weight of phosphoric acid, 3% to 5% by weight of chromic acid and 0.5% to 2% by weight of hydrofluoric acid, and the concentration of all these acids can be 13.5% to 18% by weight. The treatment temperature is preferably, for example, 42°C to 48°C. The film thickness of the coated film is preferably 0.3μm to 15μm.

[0566] The boehmite treatment is carried out by, for example, immersing the conductive substrate in deionized water at a temperature of 90° C. to 100° C. for 5 to 60 minutes or contacting the conductive substrate with hot steam at a temperature of 90° C. to 120° C. for 5 to 60 minutes. The film thickness of the coated film is preferably 0.1 μm to 5 μm. Anodization can be further performed using an electrolyte having low film solubility (such as adipic acid, boric acid, borates, phosphates, phthalates, maleates, benzoates, tartrates, and citrates).

[0567] Hereinafter, each layer other than the undercoat layer in the first to third photoreceptors is described in detail.

[0568] [Middle layer]

[0569] Although not shown, an intermediate layer may be further provided between the undercoat layer and the photosensitive layer.

[0570] The intermediate layer is, for example, a layer containing a resin. Examples of the resin used for the intermediate layer include polymer compounds such as acetal resins (such as 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, and melamine resins.

[0571] The intermediate layer may be a layer containing an organic metal compound. Examples of the organic metal compound used for the intermediate layer include organic metal compounds containing metal atoms such as zirconium, titanium, aluminum, manganese and silicon.

[0572] These compounds used for the intermediate layer may be used alone or as a mixture or polycondensate of a plurality of compounds.

[0573] Among these, the intermediate layer is preferably a layer containing an organic metal compound having a zirconium atom or a silicon atom.

[0574] The formation of the intermediate layer is not particularly limited, and a known formation method is used. For example, the intermediate layer is formed by forming a coating film of an intermediate layer-forming coating liquid obtained by adding the above-mentioned components to a solvent, and drying the coating film by heating as necessary.

[0575] As a coating method for forming the intermediate layer, common coating methods such as a dip coating method, an extrusion coating method, a wire rod coating method, a spray coating method, a knife coating method, a blade coating method, and a curtain coating method can be used.

[0576] The film thickness of the intermediate layer is preferably set to, for example, 0.1 μm to 3 μm.

[0577] [Function-separated photosensitive layer]

[0578] [Charge Generation Layer]

[0579] 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 deposited layer of the charge generating material. The deposited layer of the charge generating material is suitable for the case where an incoherent light source such as a light emitting diode (LED) or an organic electroluminescent (EL) image array is used.

[0580] 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.

[0581] Among these materials, metal phthalocyanine pigments or metal-free phthalocyanine pigments are preferably used as charge generating materials in order to cope with laser exposure in the near infrared region. Specifically, for example, hydroxygallium phthalocyanine, chlorogallium phthalocyanine, dichlorotin phthalocyanine, and titanyl phthalocyanine are more preferred.

[0582] On the other hand, in order to cope with laser exposure in the near ultraviolet region, as the charge generating material, condensed aromatic pigments such as dibromoanthraquinone; thioindigo pigments; tetraazaporphyrin compounds; zinc oxide; trigonal selenium; and disazo pigments are preferred.

[0583] In addition, in the case of using an incoherent light source with an emission center wavelength of 450nm to 780nm such as an LED or an organic EL image array, the above-mentioned charge generating material can be used. However, from the perspective of resolution, when a thin film of 20μm or less is used as a photosensitive layer, the electric field intensity in the photosensitive layer increases, and charge reduction and image defects called so-called black spots due to charge injection from the substrate tend to occur. This tendency is obvious when using a charge generating material that easily causes dark current in a p-type semiconductor (such as trigonal selenium or phthalocyanine pigment).

[0584] In contrast, when an n-type semiconductor such as a condensed ring aromatic pigment, a perylene pigment, and an azo pigment is used as a charge generating material, dark current is not easily generated, and image defects called black spots can be prevented even in a thin film.

[0585] The n-type is determined based on the polarity of the flowing photocurrent using a commonly used time-of-flight method, and the type in which the photocurrent easily flows using electrons rather than holes as carriers is determined to be the n-type.

[0586] The binder resin used for the charge generating layer is selected from a wide range of insulating resins. In addition, the binder resin may be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinyl anthracene, polyvinyl pyrene and polysilane.

[0587] Examples of the binder resin include polyvinyl butyral resin, polyarylate resin (such as condensation product of bisphenol and aromatic dicarboxylic acid), 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 and polyvinyl pyrrolidone resin. Here, "conductive" refers to a volume resistivity of 1×10 13 Ω·cm or more.

[0588] These binder resins may be used alone or in combination of two or more.

[0589] The mixing ratio of the charge generating material and the binder resin is preferably 10:1 to 1:10 in terms of weight ratio.

[0590] The charge generating layer may further contain other known additives.

[0591] The formation of the charge generating layer is not particularly limited, and a known formation method can be used. For example, a coating film of a charge generating layer-forming coating liquid obtained by adding the above-mentioned components to a solvent is formed, and the coating film is dried by heating as necessary to form a charge generating layer. The formation of the charge generating layer can be carried out by vapor deposition of a charge generating material. Forming a charge generating layer by vapor deposition is particularly suitable for the case where a condensed ring aromatic pigment or a perylene pigment is used as a charge generating material.

[0592] Examples of the solvent 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 and toluene. One solvent may be used alone or two or more thereof may be mixed and used.

[0593] In the method of 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, and a horizontal sand mill or a medium-free disperser such as a stirrer, an ultrasonic disperser, a roll mill, and a high-pressure homogenizer can be used. Examples of high-pressure homogenizers include a collision type that disperses by liquid-liquid collision or liquid-wall collision under high pressure, or a through type that disperses by penetrating a fine flow path under high pressure.

[0594] When dispersing, 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, preferably 0.3 μm or less, more preferably 0.15 μm or less.

[0595] Examples of the method for coating the undercoat layer (or intermediate layer) with the charge generating layer-forming coating liquid include common methods such as knife coating, wire rod coating, spray coating, dip coating, bead coating, air knife coating and curtain coating.

[0596] The film thickness of the charge generating layer is set to preferably 0.1 μm to 5.0 μm, more preferably 0.2 μm to 2.0 μm.

[0597] [Charge transport layer]

[0598] 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.

[0599] Examples of charge transport materials include: electron transport compounds, such as: quinone compounds, such as p-benzoquinone, chloranil, bromoquinone and anthraquinone; tetracyanoquinodimethane compounds; fluorenone compounds, such as 2,4,7-trinitrofluorenone; xanthone compounds; benzophenone compounds; cyanovinyl compounds; and vinyl compounds. Examples of charge transport materials also include: hole transport compounds, such as triarylamine compounds, benzidine compounds, aryl alkane compounds, aryl substituted vinyl compounds, stilbene compounds, anthracene compounds and hydrazone compounds. These charge transport materials can be used alone or in combination of two or more, but are not limited thereto.

[0600] As the charge transport material, from the viewpoint of charge mobility, a triarylamine derivative represented by the following formula (a-1) and a benzidine derivative represented by the following formula (a-2) are preferred.

[0601]

[0602] In 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.

[0603] Examples of the substituent of each of the above groups include a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. Examples of the substituent of each of the above groups also include a substituted amine group substituted with an alkyl group having 1 to 3 carbon atoms.

[0604]

[0605] In formula (a-2), R T91 and R T92 Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. T101 , R T102 , R T111 and R T112Each 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 with an alkyl group having 1 or 2 carbon atoms, an aryl group which may or may not have a substituent, -C(R T12 )=C(R T13 )(R T14 ) or -CH=CH-CH=C(R T15 )(R T16 ). 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 to 2.

[0606] Examples of the substituent of each of the above groups include a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. Examples of the substituent of each of the above groups also include a substituted amine group substituted with an alkyl group having 1 to 3 carbon atoms.

[0607] Among the triarylamine derivatives represented by the formula (a-1) and the benzidine derivatives represented by the formula (a-2), the one having "-C6H4-CH=CH-CH=C(R T7 )(R T8 )" and triarylamine derivatives having "-CH=CH-CH=C(R T15 )(R T16 )" benzidine derivatives.

[0608] As the polymer charge transport material, known materials having charge transport capability, such as poly-N-vinyl carbazole and polysilane, can be used. In particular, polyester polymer charge transport materials are particularly preferred. The polymer charge transport material can be used alone or in combination with a binder resin.

[0609] The example of the binder resin for charge transport layer includes 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 and polysilane. Among these resins, as binder resin, preferably polycarbonate resin or polyarylate resin. One of these binder resins can be used alone, or two or more thereof can be used.

[0610] The mixing ratio of the charge transport material and the binder resin is preferably 10:1 to 1:5 in terms of weight ratio.

[0611] The charge transport layer may further contain other known additives.

[0612] The charge generating layer may be formed by any known method, for example, by forming a coating film of a charge generating layer-forming coating liquid obtained by adding the above components to a solvent and drying the coating film by heating as necessary.

[0613] Examples of the solvent used to prepare the charge transport layer-forming coating solution include common organic solvents, such as aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene; ketones such as acetone and 2-butanone; halogenated aliphatic hydrocarbons such as dichloromethane, chloroform, and dichloroethane; and cyclic or linear ethers such as tetrahydrofuran and ethyl ether. One solvent may be used alone, or two or more thereof may be used in combination.

[0614] Examples of the coating method used when applying the charge transport layer forming coating liquid onto the charge generating layer include common methods such as knife coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating and curtain coating.

[0615] The film thickness of the charge transport layer is set to preferably 5 μm to 50 μm, more preferably 10 μm to 30 μm.

[0616] [Protective layer]

[0617] If necessary, a protective layer is provided on the photosensitive layer. The protective layer is provided for, for example, preventing chemical changes of the photosensitive layer during charging and further improving the mechanical strength of the photosensitive layer.

[0618] Therefore, a layer composed of a cured film (crosslinked film) can be applied to the protective layer. Examples of the layer include the layers shown in 1) or 2) below.

[0619] 1) A layer composed of a cured film of a composition containing a reactive group-containing charge transport material having a reactive group and a charge transport skeleton in the same molecule (i.e., a layer containing a polymer or a crosslinking member of a reactive group-containing charge transport material)

[0620] 2) A layer composed of a cured film of a composition containing a non-reactive charge transport material and a reactive group-containing non-charge transport material having a reactive group but not having a charge transport skeleton (i.e., a layer containing a polymer or a crosslinking member of a non-reactive charge transport material and a reactive group-containing non-charge transport material)

[0621] Examples of the reactive group of the charge transport material containing a reactive group include known reactive groups such as a chain polymerizable group, an epoxy group, -OH, -OR [wherein R represents an alkyl group], -NH2, -SH, -COOH and -SiR Q1 3-Qn (OR Q2 ) Qn [Where R Q1 represents a hydrogen atom, an alkyl group, or an aryl group which may or may not have a substituent, R Q2 represents a hydrogen atom, an alkyl group or a trialkylsilyl group, and Qn represents an integer of 1 to 3].

[0622] The chain polymerizable group is not specifically limited as long as it is a functional group capable of free radical polymerization, for example, a functional group having a group containing at least a carbon-carbon double bond. Specific examples thereof include groups containing at least one selected from vinyl, vinyl ether, vinyl thioether, styryl (vinyl phenyl), acryloyl, methacryloyl and derivatives thereof. Among these, from the viewpoint of excellent reactivity, as a chain polymerizable group, it is preferred to contain at least one selected from vinyl, styryl (vinyl phenyl), acryloyl, methacryloyl and derivatives thereof.

[0623] The charge transport skeleton of the charge transport material containing the 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 triarylamine compounds, benzidine compounds, and hydrazone compounds), wherein the skeleton has a structure conjugated with a nitrogen atom. Among these, a triarylamine skeleton is preferred.

[0624] The reactive group-containing charge transport material, the non-reactive charge transport material and the reactive group-containing non-charge transport material having a reactive group and a charge transport skeleton can be selected from known materials.

[0625] The protective layer may further contain other known additives.

[0626] The formation of the protective layer is not particularly limited, and a known formation method can be used. For example, a coating film of a protective layer-forming coating liquid obtained by adding the above-mentioned components to a solvent is formed, and the coating film is dried by heating as necessary, thereby forming the protective layer.

[0627] Examples of the solvent used for preparing the protective layer-forming coating liquid include: aromatic solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; ether solvents such as tetrahydrofuran and dioxane; cellosolve solvents such as ethylene glycol monomethyl ether; and alcohol solvents such as isopropyl alcohol and butanol. One solvent may be used alone, or two or more thereof may be mixed and used.

[0628] The protective layer-forming coating liquid may be a solvent-free coating liquid.

[0629] Examples of a method for applying the protective layer-forming coating liquid onto a photosensitive layer (eg, charge transport layer) include common methods such as dip coating, extrusion coating, wire bar coating, spray coating, knife coating, blade coating, and curtain coating.

[0630] The film thickness of the protective layer is set to, for example, preferably 1 μm to 20 μm, more preferably 2 μm to 10 μm.

[0631] [Single-layer photosensitive layer]

[0632] The single-layer photosensitive layer (charge generation / transport layer) is, for example, a layer containing a charge generation material and a charge transport material, and if necessary, also contains a binder resin and other known additives. These materials are the same as those described for the charge generation layer and the charge transport layer.

[0633] Thus, based on the total solid content in the first to third photoreceptors, the content of the charge generating material in the single-layer photosensitive layer may be 0.1 wt % to 10 wt %, preferably 0.8 wt % to 5 wt %. In addition, based on the total solid content, the content of the charge transporting material in the single-layer photosensitive layer may be 5 wt % to 50 wt %.

[0634] The method of forming the single-layer type photosensitive layer is the same as the method of forming the charge generating layer and the charge transporting layer.

[0635] The film thickness of the single-layer photosensitive layer may be 5 μm to 50 μm, and preferably 10 μm to 40 μm.

[0636] [Image forming apparatus and process cartridge]

[0637] The image forming apparatus using the first to third photoreceptors of the exemplary embodiment includes: an electrophotographic photoreceptor; a charging unit that charges the surface of the electrophotographic photoreceptor; an electrostatic latent image forming unit that forms an electrostatic latent image on the charged surface of the electrophotographic photoreceptor; a developing unit that develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image; and a transfer unit that transfers the toner image to a surface of a recording medium. As the electrophotographic photoreceptor, the electrophotographic photoreceptor of the exemplary embodiment is used.

[0638] As the image forming apparatus of the exemplary embodiment, a known image forming apparatus can be adopted. Examples thereof include: an apparatus including a fixing unit that fixes the transferred toner image to the surface of the recording medium; a direct transfer type apparatus that directly transfers the toner image formed on the surface of the electrophotographic photoreceptor to the recording medium; an intermediate transfer type apparatus that transfers the toner image formed on the surface of the electrophotographic photoreceptor to the surface of the intermediate transfer body once and transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium secondarily; an apparatus including a cleaning unit that cleans the surface of the electrophotographic photoreceptor after the toner image is transferred and before charging; an apparatus including a charge removing unit (irradiating the surface of the electrophotographic photoreceptor with charge removing light after the toner image is transferred and before charging to remove charge); and an apparatus including an electrophotographic photoreceptor heating unit (increasing the temperature of the electrophotographic photoreceptor and lowering the relative humidity).

[0639] In the case of an intermediate transfer type device, the transfer unit adopts a structure that includes, for example, the following components: an intermediate transfer body onto whose surface a toner image is transferred, a first transfer unit that transfers the toner image formed on the surface of the electronic photographic photoreceptor to the surface of the intermediate transfer body for the first time, and a second transfer unit 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.

[0640] The image forming apparatus of the exemplary embodiment may be any dry development type image forming apparatus or wet development type (development type using a liquid developer) image forming apparatus.

[0641] In the image forming apparatus of the exemplary embodiment, for example, the portion having the electrophotographic photoreceptor may have a box structure (processing box) that can be loaded and unloaded on the image forming apparatus. As the processing box, for example, a processing box containing the electrophotographic photoreceptor of the exemplary embodiment is suitable for use. In addition to the electrophotographic photoreceptor, the processing box may further contain, for example, at least one selected from the group consisting of a charging unit, an electrostatic latent image forming unit, a developing unit, and a transfer unit.

[0642] Hereinafter, an example of the image forming apparatus of the exemplary embodiment is shown, but the image forming apparatus is not limited thereto. The main parts shown in the drawings are described, and the description of other parts is omitted.

[0643] Figure 2 is a configuration diagram illustrating an example of an image forming apparatus according to the exemplary embodiment.

[0644] like Figure 2 As shown, the image forming apparatus 100 of the exemplary embodiment includes: a process cartridge 300 having an electrophotographic photoreceptor 7, an exposure device 9 (an example of an electrostatic latent image forming unit), a transfer device 40 (a first transfer device), and an intermediate transfer body 50. In the image forming apparatus 100, the exposure device 9 is provided at a position where the electrophotographic photoreceptor 7 can be exposed from the opening of the process cartridge 300, the transfer device 40 is provided at a position opposite to the electrophotographic photoreceptor 7 across the intermediate transfer body 50, and the intermediate transfer body 50 is provided so that a part thereof contacts the electrophotographic photoreceptor 7. Although not shown, the image forming apparatus 100 further includes a second transfer device that transfers the toner image transferred to the intermediate transfer body 50 to a recording medium (e.g., paper). The intermediate transfer body 50, the transfer device 40 (a first transfer device), and the second transfer device (not shown) correspond to an example of a transfer unit.

[0645] Figure 2 The process box 300 in the embodiment includes an electrophotographic photoreceptor 7, a charging device 8 (an example of a charging unit), a developing device 11 (an example of a developing unit), and a cleaning device 13 (an example of a cleaning unit), which are located in a housing and integrally carried. The cleaning device 13 has a cleaning blade (an example of a cleaning member) 131. 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, in place of the cleaning blade 131. The conductive or insulating fibrous member may be used alone or in combination with the cleaning blade 131.

[0646] exist Figure 2 In the example, as the image forming apparatus, there is shown a fibrous member 132 (roller shape) for supplying the lubricant 14 to the surface of the electrophotographic photoreceptor 7 and a fibrous member 133 (flat brush shape) for assisting cleaning, but these are provided when necessary.

[0647] Hereinafter, the configuration of the image forming apparatus according to the exemplary embodiment will be described.

[0648] -Charging device-

[0649] As the charging device 8, for example, a contact type charger using a conductive or semiconductive charging roller, a charging brush, a charging film, a charging rubber blade, or a charging tube, etc. can be used. In addition, a non-contact type roller charger, a known charger such as a scorotron charger or a corotron charger using corona discharge can also be used.

[0650] -Exposure device-

[0651] Examples of the exposure device 9 include an optical system device that exposes the surface of the electrophotographic photoreceptor 7 to light (such as semiconductor laser, LED light, liquid crystal shutter light) according to the image data. The wavelength of the light source is within the spectral sensitivity range of the electrophotographic photoreceptor. As the wavelength of the semiconductor laser, near-infrared with an emission wavelength of around 780nm is mostly used. However, the wavelength is not limited to this, and a laser with an emission wavelength of 600nm band or a laser with an emission wavelength of 400nm to 450nm as a blue laser can also be used. In addition, a surface-emitting laser light source capable of outputting multiple beams can also effectively form a color image.

[0652] -Developing device-

[0653] Examples of the developing device 11 include general developing devices that develop an image by contact or non-contact with a developer. The developing device 11 is not particularly limited as long as it has the above-mentioned function, and can be selected according to the purpose. Examples thereof include known developing machines having a function of attaching a single-component developer or a two-component developer to the electrophotographic photoreceptor 7 using a brush, a roller, or the like.

[0654] In the examples, it is preferable to use a developing roller holding a developer on its surface.

[0655] The developer used in the developing device 11 may be a single-component developer of only toner or a two-component developer containing toner and a carrier. In addition, the developer may be magnetic or non-magnetic. Known developers may be used for these developers.

[0656] -Cleaning device-

[0657] As the cleaning device 13 , a cleaning blade type device including a cleaning blade 131 is used.

[0658] In addition to the cleaning blade type, a brush cleaning type and a simultaneous development cleaning type may also be employed.

[0659] -Transfer device-

[0660] Examples of the transfer device 40 include a contact type transfer charger using a belt, a roller, a film, a rubber blade, or the like, and a known transfer charger such as a scorotron transfer charger or a corotron transfer charger using corona discharge.

[0661] -Intermediate transfer body-

[0662] As the intermediate transfer body 50, a belt-like member (intermediate transfer belt) made of polyimide, polyamideimide, polycarbonate, polyarylate, polyester or rubber etc. imparted with semiconductivity can be used. In addition, as the form of the intermediate transfer body, a drum-like member can be used instead of a belt.

[0663] Figure 3 is a configuration diagram illustrating another example of the image forming apparatus according to the exemplary embodiment.

[0664] Figure 3 The image forming apparatus 120 shown is a tandem type multicolor image forming apparatus equipped with four process cartridges 300. The image forming apparatus 120 has the following configuration: the four process cartridges 300 are arranged in parallel on the intermediate transfer body 50, and one electrophotographic photoreceptor is used for each color. The image forming apparatus 120 has the same configuration as the image forming apparatus 100 except for the tandem type.

[0665] Example

[0666] Hereinafter, the electrophotographic photoreceptor of the present disclosure will be described in more detail by providing examples. Without departing from the main purpose of the present disclosure, the materials, dosages, proportions, and processing procedures shown in the following examples may be appropriately changed. Therefore, the scope of the electrophotographic photoreceptor of the present disclosure should not be interpreted restrictively by the following specific examples.

[0667] <Preparation of Photoreceptor>

[0668] [Example 1]

[0669] (Formation of Primer Layer)

[0670] 20 parts by weight of blocked isocyanate (SUMIDUR BL 3175, manufactured by Sumitomo Bayer Urethane Co., Ltd., with a solid content of 75% by weight) and 7.5 parts by weight of butyral resin (S-LEC BL-1, manufactured by Sekisui Chemical Co., Ltd.) were dissolved in 150 parts by weight of methyl ethyl ketone. 34 parts by weight of a mixture of pyrenone compound (1-1) and pyrenone compound (2-1) (weight ratio 1:1) were mixed into the solution and dispersed for 10 hours using a sand mill with glass beads having a diameter of 1 mm to obtain a dispersion. 0.005 parts by weight of bismuth carboxylate (K-KAT XK-640, manufactured by King Industries, Inc.) and 2 parts by weight of silicone resin particles (TOSPEARL 145, manufactured by Momentive) were added to the dispersion to obtain a coating solution for forming an undercoat layer. The cylindrical aluminum substrate was dip-coated with the coating liquid, dried and cured at 160°C for 60 minutes to form an undercoat layer having a thickness of 7 μm. The volume resistivity of the undercoat layer was measured using a ferroelectric evaluation system (QV&IV converter model 6252C, manufactured by TOYO Corporation).

[0671] (Formation of Charge Generation Layer)

[0672] As a charge generating material, a hydroxygallium phthalocyanine having diffraction peaks at positions of at least 7.3°, 16.0°, 24.9°, and 28.0° at Bragg angles (2θ±0.2°) in an X-ray diffraction spectrum using CuKα characteristic X-rays is prepared. A mixture obtained by mixing 15 parts by weight of hydroxygallium phthalocyanine, 10 parts by weight of a vinyl chloride-vinyl acetate copolymer binder resin (VMCH, manufactured by Nippon Unicar Company Limited) and 200 parts by weight of n-butyl acetate is dispersed for 4 hours using a sand mill with glass beads having a diameter of 1 mm. 175 parts by weight of n-butyl acetate and 180 parts by weight of methyl ethyl ketone are added to the resulting dispersion and stirred to obtain a coating solution for forming a charge generating layer. The coating solution is dip-coated on the undercoat layer and dried at 150°C for 15 minutes to form a charge generating layer having a thickness of 0.2 μm.

[0673] (Formation of Charge Transport Layer)

[0674] 38 parts by weight of a charge transport agent (HT-1), 10 parts by weight of a charge transport agent (HT-2) and 52 parts by weight of a polycarbonate (A) (viscosity average molecular weight: 46,000) were added to 800 parts by weight of tetrahydrofuran and dissolved therein. 8 parts by weight of a tetrafluoroethylene resin (LUBRON L5, manufactured by Daikin Industries Ltd., with an average particle size of 300 nm) was added thereto and dispersed at 5,500 rpm for 2 hours using a homogenizer (ULTRA-TURRAX manufactured by IKA) to obtain a coating liquid for forming a charge transport layer. The coating liquid was dip-coated on the charge generating layer and dried at 140°C for 40 minutes to form a charge transport layer having a thickness of 29 μm. The photoreceptor of Example 1 was obtained by the above treatment.

[0675]

[0676] [Comparative Examples 1 to 3]

[0677] A photoreceptor was prepared in the same manner as in Example 1 except that the pyrenone compound in the formation of the undercoat layer was changed to the imide compound shown in Table 1. The chemical structures of the imide compound (A), the imide compound (B) or the imide compound (C) used in Comparative Examples 1 to 3 are shown below.

[0678]

[0679] [Comparative Example 4]

[0680] A photoreceptor was prepared in the same manner as in Example 1 except that the binder resin in the formation of the undercoat layer was changed from polyurethane to polyamide and the procedure for forming the undercoat layer was changed as described below.

[0681] (Formation of Primer Layer)

[0682] 22.5 parts by weight of polyamide resin CM 8000 (Toray Industries, Inc. manufacturing) was dissolved in 120 parts by weight of methanol and 60 parts by weight of isopropanol. A mixture of 34 parts by weight of pyrenone compound (1-1) and pyrenone compound (2-1) (weight ratio 1: 1) was mixed into the solution and dispersed for 10 hours with a sand mill using glass beads having a diameter of 1 mm, thereby obtaining a dispersion. 2 parts by weight of silicone resin particles (TOSPEARL 145, Momentive manufacturing) were added to the dispersion to obtain a coating solution for forming a primer layer. The coating solution was dip-coated on a cylindrical aluminum substrate and dried and cured at 110°C for 40 minutes to form a primer layer having a thickness of 7 μm.

[0683] [Comparative Example 5]

[0684] A photoreceptor was prepared in the same manner as in Example 1, except that the binder resin in the formation of the undercoat layer was changed from polyurethane to polycarbonate and the procedure for forming the undercoat layer was changed as described below.

[0685] (Formation of Primer Layer)

[0686] 22.5 parts by weight of polycarbonate resin PANLITE TS-2050 (manufactured by Teijin Limited) was dissolved in 160 parts by weight of tetrahydrofuran. A mixture of 34 parts by weight of pyrenone compound (1-1) and pyrenone compound (2-1) (weight ratio 1:1) was mixed into the solution and dispersed for 10 hours with a sand mill using glass beads having a diameter of 1 mm, thereby obtaining a dispersion. 2 parts by weight of silicone resin particles (TOSPEARL 145, manufactured by Momentive) were added to the dispersion to obtain a coating solution for forming a primer layer. Dip-coating was performed on a cylindrical aluminum substrate with the coating solution, and dried and cured at 135°C for 50 minutes, thereby forming a primer layer having a thickness of 7 μm.

[0687] (Formation of Charge Transport Layer)

[0688] The charge transport layer was formed by the same charge transport layer formation procedure as in Example 1 except that the dip coating was changed to the spray coating.

[0689] [Examples 2 and 3]

[0690] A photoreceptor was prepared in the same manner as in Example 1, except that the addition amount of bismuth carboxylate (K-KAT and XK-640, manufactured by King Industries, Inc.) was changed as described in Table 1 in the formation of the undercoat layer.

[0691] [Examples 4 to 9]

[0692] A photoreceptor was prepared in the same manner as in Example 1, except that the pyrenone compound was changed as described in Table 1 in the formation of the undercoat layer.

[0693] [Examples 10 and 12]

[0694] A photoreceptor was prepared in the same manner as in Example 1, except that bismuth carboxylate (K-KAT and XK-640, manufactured by King Industries, Inc.) was changed to the organic acid metal salt or metal complex described in Table 1 in the formation of the undercoat layer.

[0695] The aluminum complex used in Example 10 was K-KAT 5218 (manufactured by King Industries, Inc.).

[0696] The zirconium complex used in Example 11 was K-KAT 4205 (manufactured by King Industries, Inc.).

[0697] [Examples 13 to 15]

[0698] A photoreceptor was prepared in the same manner as in Example 1, except that the metal oxide particles described in Table 1 were added to the undercoat layer-forming coating liquid.

[0699] The zinc oxide particles used in Example 13 were zinc oxide particles (volume average particle size of 70 nm and specific surface area of ​​15 m2) that were not surface treated by coupling with a silane coupling agent (3-methacryloxypropylmethyldiethoxysilane, KBE-502, manufactured by Shin-Etsu Chemical Co., Ltd.). 2 / g, MZ-150, manufactured by Tayca Corporation) was surface treated with the particles.

[0700] The volume average particle diameter of the titanium oxide particles used in Example 14 was 30 nm (TAF-1500J, manufactured by Fuji Titanium Industry Co., Ltd.).

[0701] The volume average particle size of the tin oxide particles used in Example 15 was 20 nm (S1, manufactured by Mitsubishi Materials Corporation).

[0702] <Photoreceptor Performance Evaluation>

[0703] The photoreceptors of each of the aforementioned Examples and Comparative Examples were installed in an image forming apparatus DOCUCENTRE C5570 (manufactured by Fuji Xerox Co., Ltd.) and the following performance evaluations were performed in an environment of a temperature of 30° C. and a relative humidity of 85%.

[0704] [Leakage resistance]

[0705] The leakage resistance was evaluated based on a phenomenon in which a spot image defect occurs when current leaks in a photoreceptor.

[0706] An image with a density of 20% was continuously output on 20,000 sheets of A4 paper, and 10 hours later, an image with a density of 20% was output on 10 sheets of A4 paper in an environment of a temperature of 28°C and a relative humidity of 80%. The presence or absence of mottled image defects was visually observed on all 10 sheets, and the degree of image defects was classified into the following A to C.

[0707] A: No spot image defects.

[0708] B: The number of spot image defects is less than 10, which is acceptable for practical use.

[0709] C: There are 10 or more spot image defects, which becomes a problem in practical use.

[0710] [Charge retention characteristics]

[0711] A surface potential probe of an electrometer (TREK 334, manufactured by Trek, Inc.) was installed at a position 1 mm away from the photoreceptor surface.

[0712] After the surface of the photoreceptor was charged to -700 V, the potential drop amount (dark decay amount) after 0.1 seconds was measured, and the potential drop amount was classified into the following A to C.

[0713] A: The potential drop is less than 25V

[0714] B: The potential drop is 25V or more and less than 50V

[0715] C: Potential drop is 50V or more

[0716] [Preventing residual potential from rising]

[0717] A surface potential probe of an electrometer (TREK 334, manufactured by Trek, Inc.) was installed at a position 1 mm away from the photoreceptor surface.

[0718] The photoreceptor surface was charged to -700 V and then exposed to monochromatic light with a wavelength of 780 nm (half width 20 nm, light intensity 1.5 μJ / cm 2 ) (Irradiation time: 80 msec). The surface potential (residual potential) was measured after 330 msec had passed from the start of exposure.

[0719] The above measurement was performed before and after continuously outputting an image with a density of 20% on 20,000 A4 sheets. The residual potential difference was obtained by subtracting the residual potential before output from the residual potential after output. The residual potential difference was classified into the following A to C.

[0720] A: The residual potential difference is less than 100V, which is no problem in practical use.

[0721] B: The residual potential difference is 100 V or more and less than 150 V, which is acceptable for practical use.

[0722] C: The residual potential difference is 150 V or more, which is a problem in practical use.

[0723] [Prevent foreign matter from sticking]

[0724] The prevention of foreign matter adhesion was evaluated by using a spot image defect phenomenon due to the flow of current when the carbon fibers penetrated the photosensitive layer and the undercoat layer and reached the aluminum substrate.

[0725] A certain amount of carbon fiber (average diameter 7 μm, average length 30 μm) was mixed in a developer to a concentration of 0.1% by weight, and an image with a concentration of 20% was continuously output on 20,000 sheets of A4 paper. Next, an image with a concentration of 20% was output on 10 sheets of A4 paper. In the image on the 10th sheet, the presence or absence of a spot image defect was visually observed, and the degree of the image defect was classified into the following A to C.

[0726] A: No spot image defects.

[0727] B: The number of spot image defects is less than 10, which is acceptable for practical use.

[0728] C: There are more than 10 spot image defects, which becomes a problem in actual use.

[0729]

[0730] <Preparation of Photoreceptor>

[0731] [Example 1A]

[0732] (Formation of Primer Layer)

[0733] 20 parts by weight of blocked isocyanate (SUMIDUR BL 3175, manufactured by Sumitomo Bayer Urethane Co., Ltd., with a solid content of 75% by weight), 7.5 parts by weight of butyral resin (S-LEC BL-1, manufactured by Sekisui Chemical Co., Ltd.) and 0.005 parts by weight of catalyst dioctyltin dilaurate were dissolved in 143 parts by weight of methyl ethyl ketone. 50 parts by weight of a mixture of pyrenone compound (1-1) and pyrenone compound (2-1) (weight ratio 1:1) and 10 parts by weight of acceptor compound (6-5) were mixed into the solution and dispersed with a sand mill using glass beads having a diameter of 1 mm for 120 minutes to obtain a coating solution for forming an undercoat layer. The coating solution was dip-coated on a cylindrical aluminum substrate by dip coating, and dried and cured at 160° C. for 60 minutes to form an undercoat layer 1 having a thickness of 18.7 μm.

[0734] (Formation of Charge Generation Layer)

[0735] As a charge generating material, a hydroxygallium phthalocyanine having diffraction peaks at positions of at least 7.3°, 16.0°, 24.9° and 28.0° at Bragg angles (θ±0.2°) in an X-ray diffraction spectrum using CuKα characteristic X-rays is prepared. A mixture comprising 15 parts by weight of hydroxygallium phthalocyanine, 10 parts by weight of a vinyl chloride-vinyl acetate copolymer binder resin (VMCH, manufactured by Nippon Unicar Company Limited) as a binder resin and 200 parts by weight of n-butyl acetate is dispersed for 4 hours using a sand mill with glass beads having a diameter of 1 mm. 175 parts by weight of n-butyl acetate and 180 parts by weight of methyl ethyl ketone are added to the resulting dispersion and stirred to obtain a coating solution for forming a charge generating layer. The coating solution for forming a charge generating layer is dip-coated on the undercoat layer on the cylindrical aluminum substrate and dried at room temperature (25°C) to form a charge generating layer having a thickness of 0.2 μm.

[0736] (Formation of Charge Transport Layer)

[0737] First, a polycarbonate copolymer (1) is obtained as follows.

[0738] In a flask containing a phosgene blowing tube, a thermometer and a stirrer, 106.9 g (0.398 mol) of 1,1-bis(4-hydroxyphenyl)cyclohexane (hereinafter referred to as Z), 24.7 g (0.133 mol) of 4,4'-dihydroxybiphenyl (hereinafter referred to as BP), 0.41 g of dithionite, 825 mL (2.018 mol of sodium hydroxide) of 9.1% aqueous sodium hydroxide solution and 500 mL of dichloromethane were charged, dissolved while stirring and maintained at 18°C ​​to 21°C, and 76.2 g (0.770 mol) of phosgene was blown in for 75 minutes to carry out a phosgene reaction. After the phosgenation reaction is completed, 1.11 g (0.0075 mol) of p-tert-butylphenol and 54 mL (0.266 mol of sodium hydroxide) of a 25% aqueous sodium hydroxide solution are added and stirred. During the stirring, 0.18 mL (0.0013 mol) of triethylamine is added and the reaction is carried out at a temperature of 30°C to 35°C for 2.5 hours. The separated dichloromethane phase is washed with acid and water until there are no inorganic salts and amines, and then dichloromethane is removed to obtain a polycarbonate copolymer (1). With respect to this polycarbonate, the ratio of component Z to BP is 75:25.

[0739] Next, 25 parts by weight of N,N'-diphenyl-N,N'-di(3-methylphenyl)-[1,1']biphenyl-4,4'-diamine (TPD), 20 parts by weight of the compound represented by the formula (A) shown below, and 55 parts by weight of a polycarbonate copolymer (1) (viscosity average molecular weight 50,000) as a binder resin were added to 560 parts by weight of tetrahydrofuran and 240 parts by weight of toluene and dissolved to obtain a coating liquid for forming a charge transport layer. The coating liquid was dip-coated on the charge generating layer, and the resultant was dried at 135°C for 45 minutes to form a charge transport layer with a thickness of 22 μm. Through the above treatment, a photoreceptor was prepared.

[0740]

[0741] [Examples 2A to 22A]

[0742] Each photoreceptor was prepared in the same manner as in Example 1, except that the material for the undercoat layer was changed as described in Table 2.

[0743] [Comparative Examples 1A to 3A]

[0744] Each photoreceptor was prepared in the same manner as in Example 1, except that the material for the undercoat layer was changed as described in Table 2. The chemical structures of the acceptor compounds (18-1) and (18-2) used in Comparative Examples 2A and 3A are shown below.

[0745]

[0746] [Comparative Examples 4A to 6A]

[0747] Each photoreceptor was prepared in the same manner as in Example 1, except that the material for the undercoat layer was changed as described in Table 2. The chemical structures of the imide compounds (17-1) to (17-3) used in Comparative Examples 4A and 6A are shown below.

[0748]

[0749] <Photoreceptor Performance Evaluation>

[0750] The photoreceptors of the aforementioned Examples and Comparative Examples were installed in an image forming apparatus DOCU CENTRE-VC7775 (manufactured by Fuji Xerox Co., Ltd.) and the following performance evaluations were performed in an environment of a temperature of 30° C. and a relative humidity of 90%.

[0751] [Evaluation of photosensitivity]

[0752] A surface potential probe of an electrometer (TREK 334, manufactured by Trek, Inc.) was installed at a position 1 mm away from the photoreceptor surface.

[0753] The photoreceptor surface was charged to -700 V and then exposed to monochromatic light with a wavelength of 780 nm (half width 20 nm, light intensity 1.5 μJ / cm 2 ) (Irradiation time: 80 msec). The surface potential was measured after 330 msec had passed from the start of exposure.

[0754] The above measurement was performed before and after outputting an image with a density of 20% on 70,000 A4 sheets. The surface potential difference was calculated by subtracting the surface potential before output from the surface potential after output. The surface potential difference before and after output was divided into the following A + ~C.

[0755] A + : The surface potential difference before and after output is less than 10V.

[0756] A: The surface potential difference before and after output is 10V or more and less than 30V.

[0757] B: The surface potential difference before and after output is 30 V or more and less than 50 V.

[0758] C: The surface potential difference before and after output is 50 V or more.

[0759] [Residual potential evaluation]

[0760] A surface potential probe of an electrometer (TREK 334, manufactured by Trek, Inc.) was installed at a position 1 mm away from the photoreceptor surface.

[0761] The surface of the photoreceptor was charged to -700 V, and the residual potential after charge removal was measured.

[0762] The above measurement was performed before and after outputting an image with a density of 20% on 70,000 A4 sheets. The residual potential difference was calculated by subtracting the residual potential before output from the residual potential after output. The residual potential difference before and after output was divided into the following A + ~C.

[0763] A + : The residual potential difference before and after output is less than 20V.

[0764] A: The residual potential difference before and after output is greater than 20V and less than 50V.

[0765] B: The residual potential difference before and after output is 50V or more and less than 100V.

[0766] C: The residual potential difference before and after output is 100V or more.

[0767] Table 2

[0768]

[0769] [Example 1B]

[0770] (Formation of Primer Layer)

[0771] 60 parts by weight of the charge transport material 1-1, 20 parts by weight of a monomer as a diallyl phthalate compound (M-DAP-A, DAISO DAP 100 monomer, manufactured by Osaka Soda Co., Ltd.) and 20 parts by weight of a prepolymer as a diallyl phthalate compound (P-DAP-A, DAISO ISO DAP, manufactured by Osaka Soda Co., Ltd.) were mixed with each other and dispersed with a sand mill using 1 mmφ glass beads for 120 minutes to obtain a dispersion.

[0772] 0.8 parts by weight of tert-butyl peroxybenzoate (PERBUTYL Z, manufactured by NOF CORPORATION) was added to the obtained dispersion as a polymerization initiator to obtain a coating solution for forming an undercoat layer. The coating solution was dip-coated on an aluminum substrate by dip coating and dried at 160° C. for 60 minutes under a nitrogen atmosphere. Thereafter, the coating was further dried and cured at 100° C. for 12 hours in a chamber to obtain an undercoat layer having a thickness of 3 μm.

[0773] (Formation of Charge Generation Layer)

[0774] A mixture containing 15 parts by weight of hydroxygallium phthalocyanine having diffraction peaks at positions of at least 7.3°, 16.0°, 24.9° and 28.0° in an X-ray diffraction spectrum using CuKα characteristic X-rays, 10 parts by weight of a vinyl chloride-vinyl acetate copolymer binder resin (VMCH, manufactured by Nippon Unicar Company Limited) as a binder resin and 200 parts by weight of n-butyl acetate was dispersed by stirring for 4 hours using a sand mill with glass beads having a diameter of 1 mmφ. 175 parts by weight of n-butyl acetate and 180 parts by weight of methyl ethyl ketone were added to the resulting dispersion and stirred to obtain a coating solution for forming a charge generating layer. This coating solution for forming a charge generating layer is a dip-coated undercoat. Afterwards, drying was performed at 140°C for 10 minutes to form a charge generating layer having a film thickness of 0.2 μm.

[0775] (Formation of Charge Transport Layer)

[0776] 40 parts by weight of a charge transport agent (HT-1), 8 parts by weight of a charge transport agent (HT-2) and 52 parts by weight of a polycarbonate binder resin (A) (viscosity average molecular weight: 50,000) were added to 800 parts by weight of tetrahydrofuran and dissolved therein. 8 parts by weight of a tetrafluoroethylene binder resin (manufactured by Daikin Industries Ltd., LUBRON L5, average particle size 300 nm) was added thereto and dispersed at 5,500 rpm for 2 hours using a homogenizer (ULTRA-TURRAX, manufactured by IKA) to obtain a coating liquid for forming a charge transport layer. This coating liquid was applied to the above-mentioned charge generating layer. Thereafter, drying was performed at 140° C. for 40 minutes to form a charge transport layer having a film thickness of 27 μm. In this way, an electrophotographic photoreceptor 1 was obtained.

[0777]

[0778]

[0779] [Examples 2B to 16B]

[0780] In the preparation of the undercoat layer, an electrophotographic photoreceptor was obtained by the same operation as in Example 1B except that the type and content of the charge transport material and the type and content of the binder resin were set as shown in Table 3. Next, the specific structure of the charge transport material is described.

[0781] In the charge transport material 1-3 in Example 2B, the methyl group is located at R 14 and R 18 .

[0782] In the charge transport material 1-6 in Example 3B, the methoxycarbonyl group is located at R 12 and R 16 .

[0783] In the charge transport material 1-7 in Example 4B, the ethoxycarbonyl group is located at R 13 and R 17 .

[0784] In the charge transport material 2-3 in Example 6B, the methyl group is located at R 21 and R 28 .

[0785] In the charge transport material 2-8 in Example 7B, the octyloxycarbonyl group is located at R 23 and R 27 .

[0786] Furthermore, in Example 12B, a charge transport material 3-1 having the following structure was used instead of the charge transport material 1-1.

[0787]

[0788] [Example 17B]

[0789] An electrophotographic photoreceptor was obtained by performing the same operation as in Example 1B except that the thickness of the undercoat layer was set to 10 μm.

[0790] [Example 18B]

[0791] The undercoat layer in Example 1B was configured to further contain inorganic particles. Furthermore, the same operation as in Example 1B was performed except that the undercoat layer preparation step in Example 1B was changed to the following step, thereby obtaining an electrophotographic photoreceptor.

[0792] 100 parts by weight of zinc oxide (manufactured by Tayca Corporation, average particle size: 70 nm; specific surface area: 15 m 2 / g) was mixed with 600 parts by weight of toluene by stirring, 1.2 parts by weight of a silane coupling agent (vinyl trimethoxysilane, manufactured by Shin-Etsu Silicone Co., Ltd.) was added thereto and stirred for 2 hours. Thereafter, toluene was distilled off by reduced pressure distillation, and baked at 125° C. for 2 hours to obtain zinc oxide surface-treated with a silane coupling agent.

[0793] 30 parts by weight of the surface-treated zinc oxide, 40 parts by weight of the charge transport material 1-1, 15 parts by weight of a monomer as a diallyl phthalate compound (M-DAP-A, DAISO DAP 100 monomer, manufactured by Osaka Soda Co., Ltd.) and 15 parts by weight of a prepolymer as a diallyl phthalate compound (P-DAP-A, DAISO ISO DAP, manufactured by Osaka Soda Co., Ltd.) were mixed with each other and dispersed with a sand mill using 1 mmφ glass beads for 120 minutes to obtain a dispersion.

[0794] 0.8 parts by weight of tert-butyl peroxybenzoate (PERBUTYL Z, manufactured by NOF CORPORATION) was added to the obtained dispersion as a polymerization initiator to obtain a coating solution for forming an undercoat layer. The coating solution was dip-coated on an aluminum substrate by dip coating, dried and cured at 160° C. for 60 minutes under a nitrogen atmosphere, and then further dried and cured at 100° C. for 12 hours to form an undercoat layer having a thickness of 10 μm.

[0795] For the amounts of monomers and prepolymers of diallyl phthalate compounds in the electrophotographic photoreceptors of Examples 2B to 17B, the total amount of 40 parts by weight (20 parts of monomers and 20 parts of prepolymers) in Example 1B was set to amounts having a monomer and prepolymer weight ratio shown in Table 3.

[0796] [Comparative Example 1B]

[0797] In the preparation of the undercoat layer, the same operation as in Example 1B was performed, except that the kind of the binder resin was set as shown in Table 4 and the following raw materials and solvents were used instead of the diallyl phthalate compound, thereby obtaining an electrophotographic photoreceptor.

[0798] Material for forming the polyamide resin as the binder resin: copolyamide (product number CM8000, manufactured by Toray Industries, Inc.)

[0799] Solvent: methanol, 60 parts by weight

[0800] [Comparative Example 2B]

[0801] In the preparation of the undercoat layer, the same operation as in Example 1B was performed, except that the kind of the binder resin was set as shown in Table 4 and the following raw materials and solvents were used instead of the diallyl phthalate compound, thereby obtaining an electrophotographic photoreceptor.

[0802] Material for forming melamine resin as a binder resin: melamine resin (MX-730, manufactured by Sanwa Chemical Co., Ltd.)

[0803] Solvent: 2-propanol, 60 parts by weight

[0804] [Comparative Example 3B]

[0805] In the preparation of the undercoat layer, the same operation as in Example 1B was performed except that the kind of the binder resin was set as shown in Table 4 and the following raw materials and solvents were used instead of the diallyl phthalate compound, and except that the charge transporting material was not contained, thereby obtaining an electrophotographic photoreceptor.

[0806] Material for forming the polyamide resin as the binder resin: copolyamide (product number CM8000, manufactured by Toray Industries, Inc.)

[0807] Solvent: methanol, 60 parts by weight

[0808] [Comparative Example 4B]

[0809] In the preparation of the undercoat layer, the same operation as in Example 1B was performed, except that the kind of the binder resin was set as shown in Table 4 and the following raw materials and solvents were used instead of the diallyl phthalate compound, thereby obtaining an electrophotographic photoreceptor.

[0810] · Material for forming the (meth)acrylic resin as a binder resin: methacrylate polymer (manufactured by FUJIFILM Wako Pure Chemical Corporation)

[0811] Solvent: methyl ethyl ketone, 60 parts by weight

[0812] [evaluate]

[0813] -Evaluation of charging potential and residual potential-

[0814] As the electrophotographic properties of the obtained electrophotographic photoreceptor, the potential of each part was measured by using a laser printer modified scanner (XP-15 modified machine, manufactured by Fuji Xerox Co., Ltd.) through the following process: (A) charging with a grid corotron charger with a grid applied voltage of -700 V under normal temperature and humidity (20°C, 40%) environment, (B) after 1 second, the electric potential of each part was measured by a 780nm semiconductor laser at a voltage of 10.0 erg / cm 2 irradiated with light to discharge, and after 3 seconds, 50.0erg / cm 2 The evaluation results are shown in Tables 3 and 4.

[0815] (A) Charging potential evaluation criteria (acceptable range is A and B)

[0816] A: The difference with the grid voltage is less than 10V

[0817] B: The difference with the grid voltage is less than 20V

[0818] C: The difference with the grid voltage is more than 20V

[0819] (B) Residual potential evaluation criteria (acceptable range is A and B)

[0820] A: Less than 20V

[0821] B: 20V or more and less than 40V

[0822] C: 40V or more and less than 80V

[0823] D: 80V or above

[0824] -Image quality evaluation-

[0825] The obtained photoreceptor was mounted on a copier "DOCU CENTRE COLOR 500" (manufactured by Fuji Xerox Co., Ltd.), and 10 consecutive images were output under the conditions of 20°C and 40% RH. The image was a picture in which a region having a white letter "G" in a black solid image having an image density of 100% and a halftone image region having an image density of 40% were printed. The evaluation results are shown in Tables 3 and 4.

[0826] (Ghost Review)

[0827] For the image output of the first page (initial image) and the image after 10 pages of output (image after 10 pages of output), the density change of the character G was visually confirmed. The evaluation criteria were as follows: A and B fell within the acceptable range.

[0828] A: No concentration change

[0829] B: Slight concentration change, which is no problem in actual use

[0830] C: Unacceptable concentration variation for practical use

[0831] (Evaluation of halftone image density unevenness)

[0832] The evaluation of the halftone image density non-uniformity was performed by visually checking the random density variation in the halftone image with a density of 40% in the first output page of the image (initial image) and the image after 10 pages of output (image after 10 pages of output). The evaluation criteria are as follows. A and B fall within the acceptable range.

[0833] A: No concentration change

[0834] B: Slight concentration change, which is no problem in actual use

[0835] C: Unacceptable concentration variation for practical use

[0836] -Leakage current evaluation-

[0837] The photoreceptor was mounted on the drum cartridge, and a pinhole with a diameter of 0.1 mm was passed through the photoreceptor to the substrate. A 50% halftone image was printed under a low temperature and low humidity (10°C, 15% RH) environment and a high temperature and high humidity (28°C, 85% RH) environment. For these printed images, the band-shaped image defects corresponding to the pinhole portion of the photoreceptor were determined according to the following criteria. The evaluation results are shown in Tables 3 and 4. A to C fell within the acceptable range.

[0838] A: Color dots with a diameter of less than 1.0 mm

[0839] B: Band-shaped image defects less than 10 mm occur

[0840] C: Band-shaped image defects longer than 10 mm and less than 30 mm occur

[0841] D: Band-shaped image defect longer than 30 mm and less than 35 mm

[0842] E: Band-shaped image defects larger than 35 mm occur

[0843]

[0844]

[0845] From the above results, it can be found that in the electrophotographic photoreceptors of the examples, the residual potential can be prevented from rising when repeated images are formed, as compared with the electrophotographic photoreceptors of the comparative examples. In addition, it can be found that in the electrophotographic photoreceptors of Examples 13B and 14B in which the binder resin obtained by polymerizing a diallyl phthalate compound and a (meth)acrylic monomer is used for the undercoat layer, the leakage current is prevented, as compared with the electrophotographic photoreceptor of Example 1B in which the binder resin obtained by polymerizing only a diallyl phthalate compound is used for the undercoat layer.

[0846] The foregoing description of exemplary embodiments of the present invention is provided for the purpose of illustration and description. It is not intended to be exhaustive or to limit the present invention to the precise form disclosed. Obviously, many improvements and variations are obvious to those skilled in the art. The embodiments are selected and described in order to best explain the principles of the present invention and its practical use, thereby enabling other technical personnel in the field to understand the various embodiments and various improvements of the present invention suitable for the specific use envisioned. The scope of the present invention should be limited by the appended claims and their equivalents.

Claims

1. An electrophotographic photoreceptor comprising: Conductive substrate; A primer layer disposed on the conductive substrate; and A photosensitive layer is provided on the base coating layer, in, The photosensitive layer is a functional separation type photosensitive layer having a charge generating layer containing a charge generating material and a charge transporting layer containing a charge transporting material, or a single layer type photosensitive layer containing a charge generating material and a charge transporting material, The primer layer contains: at least one pyrone compound selected from the group consisting of compounds represented by formula (1) shown below, at least one pyrone compound selected from the group consisting of compounds represented by formula (2) shown below, and at least one receptor compound selected from the group consisting of compounds represented by formula (13) shown below and compounds represented by formula (15) shown below: In formula (1), R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 Each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom, and R 11 and R 12 Can be connected to each other to form a ring, R 12 and R 13 Can be connected to each other to form a ring, R 13 and R 14 Can be connected to each other to form a ring, R 15 and R 16 Can be connected to each other to form a ring, R 16 and R 17 can be connected to each other to form a ring, and R 17 and R 18 Can be connected to each other to form a ring; In formula (2), R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 and R 28 Each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom, and R 21 and R 22 Can be connected to each other to form a ring, R 22 and R 23 Can be connected to each other to form a ring, R 23 and R 24 Can be connected to each other to form a ring, R 25 and R 26 Can be connected to each other to form a ring, R 26 and R 27 can be connected to each other to form a ring, and R 27 and R 28 Can be connected to each other to form a ring: In formula (13), R 131 , R 132 , R 133 , R 134 , R 135 , R 136 , R 137 and R 138 each independently represents a hydrogen atom, a halogen atom, an alkyl group, a carboxyl group or a hydroxyl group; and In formula (15), R 151 , R 152 , R 153 , R 154 , R 155 , R 156 , R 157 , R 158 , R 159 and R 160 Each independently represents a hydrogen atom, a halogen atom, an alkyl group, a carboxyl group or a hydroxyl group, and adjacent groups may be linked to each other to form a ring, provided that R 151 , R 152 , R 153 , R 154 , R 155 , R 156 , R 157 , R 158 , R 159 and R 160 At least one of represents a carboxyl group or a hydroxyl group.

2. The electrophotographic photoreceptor according to claim 1, in, The total content of the acceptor compound is 2 wt % to 30 wt % based on the total content of the pyrenone compound contained in the primer layer.

3. The electrophotographic photoreceptor according to claim 1, in, The total content of the pyrenone compound is 50 wt % to 90 wt % relative to the total solid content of the primer layer.

4. A process cartridge that can be loaded and unloaded on an image forming device, the process cartridge comprising: The electrophotographic photoreceptor according to any one of claims 1 to 3.

5. An image forming device comprising: The electrophotographic photoreceptor according to any one of claims 1 to 3; a charging unit that charges the surface of the electrophotographic photoreceptor; an electrostatic latent image forming unit that forms an electrostatic latent image on the charged surface of the electrophotographic photoreceptor; a developing unit that develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image; and A transfer unit transfers the toner image onto a surface of a recording medium.

Images