WO2024204544A1 - 電子写真感光体 - Google Patents

電子写真感光体 Download PDF

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Publication number
WO2024204544A1
WO2024204544A1 PCT/JP2024/012663 JP2024012663W WO2024204544A1 WO 2024204544 A1 WO2024204544 A1 WO 2024204544A1 JP 2024012663 W JP2024012663 W JP 2024012663W WO 2024204544 A1 WO2024204544 A1 WO 2024204544A1
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group
formula
optionally substituted
substituent
compound
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English (en)
French (fr)
Japanese (ja)
Inventor
司 長谷川
ラミレス マヌエル エミリオ オテロ
英貴 五郎丸
明 安藤
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Mitsubishi Chemical Corp
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Mitsubishi Chemical Corp
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G5/00—Recording-members for original recording by exposure, e.g. to light, to heat or to electrons; Manufacture thereof; Selection of materials therefor
    • G03G5/02—Charge-receiving layers
    • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
    • G03G5/043—Photoconductive layers characterised by having two or more layers or characterised by their composite structure
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G5/00—Recording-members for original recording by exposure, e.g. to light, to heat or to electrons; Manufacture thereof; Selection of materials therefor
    • G03G5/02—Charge-receiving layers
    • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
    • G03G5/043—Photoconductive layers characterised by having two or more layers or characterised by their composite structure
    • G03G5/047—Photoconductive layers characterised by having two or more layers or characterised by their composite structure characterised by the charge-generation layers or charge transport layers
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G5/00—Recording-members for original recording by exposure, e.g. to light, to heat or to electrons; Manufacture thereof; Selection of materials therefor
    • G03G5/02—Charge-receiving layers
    • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
    • G03G5/05—Organic bonding materials; Methods for coating a substrate with a photoconductive layer; Inert supplements for use in photoconductive layers
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G5/00—Recording-members for original recording by exposure, e.g. to light, to heat or to electrons; Manufacture thereof; Selection of materials therefor
    • G03G5/02—Charge-receiving layers
    • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
    • G03G5/06—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being organic
    • G03G5/07—Polymeric photoconductive materials
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G5/00—Recording-members for original recording by exposure, e.g. to light, to heat or to electrons; Manufacture thereof; Selection of materials therefor
    • G03G5/14—Inert intermediate or cover layers for charge-receiving layers
    • G03G5/147—Cover layers

Definitions

  • the present invention relates to an electrophotographic photoreceptor for use in copiers, printers, etc., which has at least a photosensitive layer and a protective layer sequentially formed on a conductive support, and which has improved electrical properties such as residual potential characteristics, and mechanical properties such as hardness and elastic deformation rate.
  • the photoconductor In printers and copiers, when a charged organic photoconductor (OPC) drum is irradiated with light, that part is discharged and an electrostatic latent image is created, and an image can be obtained by attaching toner to the electrostatic latent image.
  • OPC organic photoconductor
  • the photoconductor In devices that use electrophotography in this way, the photoconductor is the core material.
  • This type of organic photoreceptor has a large range of material selection and is easy to control the characteristics of the photoreceptor, so that "functionally separated photoreceptors" in which the functions of generating and transporting charges are shared by different compounds have become mainstream.
  • a single-layer electrophotographic photoreceptor (hereinafter referred to as a "single-layer photoreceptor") having a charge generating material (CGM) and a charge transport material (CTM) in the same layer, and a laminated electrophotographic photoreceptor (hereinafter referred to as a "laminated photoreceptor") formed by laminating a charge generating layer containing a charge generating material (CGM) and a charge transport layer containing a charge transport material (CTM) are known.
  • CGM charge generating material
  • CTM charge transport material
  • the charging method of the photoreceptor can be a negative charging method in which the surface of the photoreceptor is negatively charged, or a positive charging method in which the surface of the photoreceptor is positively charged.
  • Combinations of layer structures and charging methods of photoreceptors currently in practical use include "negatively charged multi-layer photoreceptors" and "positively charged single-layer photoreceptors.”
  • a "positively charged single-layer photoreceptor” generally has a structure in which an undercoat layer (UCL) made of resin or the like is provided on a conductive substrate such as an aluminum tube, and a single-layer photosensitive layer made of a charge generating material (CGM), a hole transport material (HTM), an electron transport material (ETM), and a resin or the like is provided on top of that (see, for example, Patent Document 1).
  • UCL undercoat layer
  • CGM charge generating material
  • HTM hole transport material
  • ETM electron transport material
  • the surface of the photoconductor is first charged using corona discharge or contact methods, and then the photoconductor is exposed to light to neutralize the surface charge, forming an electrostatic latent image due to the potential difference with the surrounding surface.
  • Toner is then brought into contact with the photoconductor surface to form a toner image that corresponds to the electrostatic latent image, which is then transferred to paper or other material and heated to melt and fix it, completing the print.
  • the basic structure of an electrophotographic photoreceptor is a photosensitive layer formed on a conductive support, but a protective layer may also be provided on the photosensitive layer to improve abrasion resistance, etc.
  • a photoreceptor As a technique for improving the mechanical strength or abrasion resistance of the photoreceptor surface, a photoreceptor has been disclosed in which a layer containing a compound having a chain-polymerizable functional group as a binder resin is formed in the outermost layer of the photoreceptor, and this is polymerized by applying energy such as heat, light, or radiation to form a cured resin layer (see, for example, Patent Documents 1 and 2).
  • Such a protective layer is generally formed by dissolving a curable composition containing a compound having a chain polymerizable functional group in an organic solvent to prepare a coating liquid for forming a protective layer, and then coating the coating liquid for forming a protective layer on the surface of the photoreceptor.
  • a protective layer is provided to improve the abrasion resistance of a photoreceptor.
  • a protective layer using a curable compound (a compound having a chain-polymerizable functional group) is particularly excellent in mechanical strength.
  • the protective layer is also required to have good electron transport properties.
  • the protective layer is required to have high hardness and elastic deformation rate. That is, in order to improve the wear resistance and electrical properties of the photoreceptor, it is considered effective to use a compound having an electron transport structure as the curable compound for forming the protective layer.
  • the object of the present invention is to provide an electrophotographic photoreceptor having at least a photosensitive layer and a protective layer in that order on a conductive support, which has excellent electrical properties such as residual potential characteristics, and mechanical properties such as hardness and elastic deformation rate, and further has excellent solubility in organic solvents of the compound used to form the protective layer.
  • the present inventors have found that, when a compound represented by the following formula (1) and satisfying the following formulas (I) and (II-1), or a compound represented by the following formula (1) and satisfying the following formulas (I) to (III), is used as a compound for forming a protective layer, the solubility is improved and the residual potential, hardness, and elastic deformation rate are also improved.
  • the present invention has been achieved based on these findings, and has the following gist.
  • An electrophotographic photoreceptor having at least a photosensitive layer and a protective layer in this order on a conductive support,
  • the protective layer contains a compound represented by the following formula (1), and the compound represented by the formula (1) satisfies the following formulas (I) and (II-1):
  • X represents an electron transporting skeleton having a valence of n.
  • A is a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkoxy group, an optionally substituted aryloxy group, an optionally substituted heteroaryloxy group, an optionally substituted alkoxycarbonyl group, an optionally substituted dialkylamino group, an optionally substituted diarylamino group, an optionally substituted arylalkylamino group, an optionally substituted acyl group, an optionally substituted haloalkyl group, an optionally substituted alkylthio group, an optionally substituted arylthio group, an optionally substituted silyl group, an optionally substituted siloxy group, an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, a group represented by the following formula (2), or a group represented by the following formula (1B).
  • n represents an integer of 1 or more.
  • A is a group represented by the following formula (2) or a group represented by the following formula (1B).
  • n is 2 or more, a plurality of A's may be the same or different, and at least one A's is a group represented by the following formula (2) or a group represented by the following formula (1B).
  • R 1 and R 2 each independently represent a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, a heteroaryloxy group which may have a substituent, an alkoxycarbonyl group which may have a substituent, a dialkylamino group which may have a substituent, a diarylamino group which may have a substituent, an arylalkylamino group which may have a substituent, an acyl group which may have a substituent, a haloalkyl group which may have a substituent, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a silyl group which may have a substituent, a siloxy group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which
  • L 1 and L 2 each independently represent a direct bond, a divalent group, a group represented by the following formula (1A) or a group represented by the following formula (3A).
  • R3 represents a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, a heteroaryloxy group which may have a substituent, an alkoxycarbonyl group which may have a substituent, a dialkylamino group which may have a substituent, a diarylamino group which may have a substituent, an arylalkylamino group which may have a substituent, an acyl group which may have a substituent, a haloalkyl group which may have a substituent, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a silyl group which may have a substituent, a siloxy group which may have a substituent,
  • * represents a bond to any atom in formula (1) and formula (2).
  • B1 and B2 each independently represent a direct bond or a divalent group.
  • n is an integer of 1 or more.
  • M ETM represents the molecular weight of the compound represented by formula (1).
  • M X represents the represents the molecular weight of a compound in which all of the bonding sites of X are replaced with hydrogen atoms.
  • An electrophotographic photoreceptor having at least a photosensitive layer and a protective layer in this order on a conductive support,
  • the protective layer contains a polymer of a compound represented by the following formula (1), and the compound represented by the formula (1) satisfies the following formulas (I), (II-2), and (III):
  • X represents an n-valent electron transporting skeleton.
  • A is a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkoxy group, an optionally substituted aryloxy group, an optionally substituted heteroaryloxy group, an optionally substituted alkoxycarbonyl group, an optionally substituted dialkylamino group, an optionally substituted diarylamino group, an optionally substituted arylalkylamino group, an optionally substituted acyl group, an optionally substituted haloalkyl group, an optionally substituted alkylthio group, an optionally substituted arylthio group, an optionally substituted silyl group, an optionally substituted siloxy group, an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, a group represented by the following formula (2), or a group represented by the following formula (1B).
  • n represents an integer of 1 or more.
  • A is a group represented by the following formula (2) or a group represented by the following formula (1B).
  • A is a group represented by the following formula (2)
  • at least one of Z is a polymerizable functional group.
  • R3 is a polymerizable functional group.
  • n is 2 or more, a plurality of A's may be the same as or different from each other, and at least one A's is a group represented by the following formula (2) or a group represented by the following formula (1B), and contains at least one polymerizable functional group in the structure.
  • R 1 and R 2 each independently represent a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, a heteroaryloxy group which may have a substituent, an alkoxycarbonyl group which may have a substituent, a dialkylamino group which may have a substituent, a diarylamino group which may have a substituent, an arylalkylamino group which may have a substituent, an acyl group which may have a substituent, a haloalkyl group which may have a substituent, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a silyl group which may have a substituent, a siloxy group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group
  • L 1 and L 2 each independently represent a direct bond, a divalent group, a group represented by the following formula (1A) or a group represented by the following formula (3A).
  • R3 represents a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, a heteroaryloxy group which may have a substituent, an alkoxycarbonyl group which may have a substituent, a dialkylamino group which may have a substituent, a diarylamino group which may have a substituent, an arylalkylamino group which may have a substituent, an acyl group which may have a substituent, a haloalkyl group which may have a substituent, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a silyl group which may have a substituent, a siloxy group which may have a substituent,
  • * represents a bond to any atom in formula (1) and formula (2).
  • B1 and B2 each independently represent a direct bond or a divalent group.
  • n is an integer of 1 or more.
  • M ETM represents the molecular weight of the compound represented by formula (1).
  • M X represents the molecular weight of the compound in which all of the bonding sites of X in formula (1) have been replaced with hydrogen atoms.
  • a ETM represents the number of polymerizable functional groups contained per 1,000 molecular weight of the compound represented by formula (1).
  • L 1 and L 2 are a group represented by the formula (1A) or a group represented by the formula (3A).
  • the electrophotographic photoreceptor according to any one of the above [1] to [5].
  • R 110 represents a hydrogen atom or an alkyl group which may have a substituent, and * represents the bonding position.
  • R 1 is an alkyl group which may have a substituent.
  • an electrophotographic photoreceptor having at least a photosensitive layer and a protective layer sequentially on a conductive support, which is excellent in electrical properties such as residual potential characteristics and mechanical properties such as hardness and elastic deformation rate.
  • the compound used to form the protective layer has excellent solubility in organic solvents such as alcohol-based solvents, when forming the protective layer, an electrophotographic photoreceptor having excellent electrical and mechanical properties can be efficiently manufactured with good workability due to its good solvent solubility.
  • 1 is a diagram illustrating an example of the configuration of an image forming apparatus that can be configured using an electrophotographic photoreceptor according to an example of the present invention.
  • 1 is a graph showing a general relationship between the indentation depth of an indenter and a load curve when measuring the Martens hardness and elastic deformation rate of a photoreceptor.
  • An electrophotographic photoreceptor according to an embodiment of the present invention (hereinafter also referred to as "photoreceptor of the present invention") is an electrophotographic photoreceptor having at least a photosensitive layer and a protective layer in this order on a conductive support, and the protective layer contains the compound A or B of the present invention described below.
  • the compound A or B of the present invention has a polymerizable functional group in one molecule, it may be present in the form of a polymer in the protective layer after curing.
  • the compound A or B of the present invention may be polymerized with itself to form a polymer, or when the protective layer contains a curable compound, it may be polymerized with the curable compound to form a polymer.
  • the photoreceptor of the present invention may optionally have layers other than the photosensitive layer and the protective layer.
  • the charging method of the photoconductor of the present invention may be either a negative charging method in which the surface of the photoconductor is negatively charged or a positive charging method in which the surface of the photoconductor is positively charged.
  • the positive charging method is preferred because it is considered that the effect of the present invention can be further obtained with the positive charging method.
  • the side opposite the conductive support is the upper side or front side, and the conductive support side is the lower side or back side.
  • the protective layer of the photoreceptor of the present invention (sometimes referred to as “the present protective layer”) contains a polymer of an electron transporting compound A (sometimes referred to as “compound A of the present invention") represented by the following formula (1) and satisfying the following formulas (I) and (II-1), or an electron transporting compound B (sometimes referred to as “compound B of the present invention”) represented by the following formula (1) and satisfying the following formulas (I), (II-2), and (III).
  • compound A and B of the present invention means compound A or B of the present invention
  • the compound of the present invention means compounds A and B of the present invention inclusively.
  • electron transporting compound refers to a compound that has electron transport properties, in other words, a compound that has an electron transporting skeleton.
  • M ETM represents the molecular weight of the compound represented by formula (1).
  • M X represents the represents the molecular weight of a compound in which all of the bonding sites of X are replaced with hydrogen atoms.
  • M ETM ⁇ 700 (I) M X /M ETM >0.31 (II-2) A ETM ⁇ 1.8 (III)
  • M ETM represents the molecular weight of the compound represented by formula (1).
  • M X represents the molecular weight of the compound represented by formula (1).
  • a ETM represents the molecular weight of a compound in which all of the bonding sites of X in the formula (1) are replaced with hydrogen atoms. Represents the number of.
  • the mechanism by which the photoreceptor of the present invention having a protective layer containing the compound A of the present invention exhibits excellent electrical properties is believed to be as follows. Since compound A of the present invention has an electron transport structure, by using compound A of the present invention in the formation of the protective layer, charge injection from the photosensitive layer to the protective layer and charge mobility to the outermost surface are enhanced through the electron transport skeleton, and an electrophotographic photoreceptor having excellent electrical properties such as residual potential characteristics can be obtained. In addition, when the compound A of the present invention has a polymerizable functional group, the compound A of the present invention is polymerized in the step of forming the protective layer described below to form a polymer, which can form a protective layer having excellent mechanical strength.
  • the polymer may be a polymer obtained by polymerizing the compound A of the present invention with itself, or, when the protective layer contains a polymerizable compound not having an electron transport skeleton, it may be a copolymer obtained by polymerizing the polymerizable compound with the compound A of the present invention.
  • compound A of the present invention is equal to or less than the upper limit of the following formula (II-1)
  • the ratio of the mother skeleton which is a hydrophobic ⁇ -conjugated skeleton falls within a preferred range, the solubility in alcohol-based solvents increases, the applicability of the coating solution when forming a protective layer improves, and a uniform protective layer without unevenness can be formed.
  • the mechanism by which the photoreceptor of the present invention having a protective layer containing a polymer of the compound B of the present invention exhibits excellent electrical properties is believed to be as follows. Since compound B of the present invention has an electron transport structure, by using compound B of the present invention in the formation of the protective layer, charge injection from the photosensitive layer to the protective layer and charge mobility to the outermost surface are enhanced through the electron transport skeleton, and an electrophotographic photoreceptor having excellent electrical properties such as residual potential characteristics can be obtained. In addition, since the compound B of the present invention has a polymerizable functional group, the compound B of the present invention is polymerized in the step of forming the protective layer described below to form a polymer, which can form a protective layer having excellent mechanical strength.
  • the polymer may be a polymer formed by polymerizing the compound B of the present invention with itself, or, when the protective layer contains a polymerizable compound not having an electron transport skeleton, it may be a copolymer formed by polymerizing the polymerizable compound with the compound B of the present invention.
  • the compound B of the present invention satisfies the formula (I) and the formula (II-2)
  • the ratio of the structure that is considered to contribute to electron transport in the protective layer increases, which is advantageous for electron transport.
  • the compound B of the present invention satisfies the formula (III)
  • the number of polymerizable functional groups in the protective layer is large, which makes it easy to form a dense network structure. As a result, the hardness and elastic deformation rate are good.
  • compound B of the present invention further satisfies formula (IV)
  • electron injection from the adjacent layer is good and the electron transport property of the main skeleton is excellent, resulting in further improved electrical properties.
  • the protective layer is the outermost layer, that is, the outermost layer located on the opposite side to the conductive support.
  • the effects of the present invention can be obtained even if the protective layer is not necessarily the outermost layer.
  • the effects can be obtained even if the protective layer is not the outermost layer.
  • composition of the present invention used in forming the protective layer of the present invention
  • electrophotographic photoreceptor of the present invention used in forming the protective layer of the present invention
  • the compound A of the present invention is preferably a compound represented by the following formula (1) and satisfying the following formulas (I) and (II-1).
  • X represents an electron transporting skeleton having a valence of n.
  • X is preferably a skeleton represented by the following formulas (A-1) to (A-27).
  • the electron transporting skeleton is a skeleton represented by the following formula (A-10), (A-11), or (A-26)
  • the electron transporting property is excellent and the electrical characteristics (VL) are further improved, which is more preferable.
  • R A11 , R A21 , R A31 , R A41 , R A51 , R A61 , R A62 , R A71 , R A72 , R A81 , R A82 , R A91 , R A92 , R A101 , R A111 , R A121 , R A131 , R A141 , R A151 , R A161 , R A171 , R A181 , R A182 , R A191 , R A192 , R A201 , R A202 , R A211 , R A212 , R A221 , R A222 , R A231 , R R , R , R, R, R , R , R, R, R, R, R, and R each independently represent a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent
  • R A11 to R A262 may be different from each other.
  • n represents an integer of 1 or more, and when n is 2 or more, a plurality of As may be the same or different.
  • a in the above formula (1) is a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkoxy group, an optionally substituted aryloxy group, an optionally substituted heteroaryloxy group, an optionally substituted alkoxycarbonyl group, an optionally substituted dialkylamino group, an optionally substituted diarylamino group, an optionally substituted arylalkylamino group, an optionally substituted acyl group, an optionally substituted haloalkyl group, an optionally substituted alkylthio group, an optionally substituted arylthio group, an optionally substituted silyl group, an optionally substituted siloxy group, an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, a group represented by the following formula (2), or a group represented by the following formula (1B).
  • “may have a substituent” means that the group can have a substituent, and includes both the case where the group has a substituent and the case where the group does not have a substituent.
  • A is a group represented by the following formula (2) or a group represented by the following formula (1B).
  • A is a group represented by the following formula (2)
  • at least one of Z is a polymerizable functional group.
  • R3 is a polymerizable functional group.
  • n is 2 or more, a plurality of A's may be the same as or different from each other, and at least one A's is a group represented by the following formula (2) or a group represented by the following formula (1B), and contains at least one polymerizable functional group in the structure.
  • At least one of A is a group represented by the following formula (2).
  • R 1 and R 2 each independently represent a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, a heteroaryloxy group which may have a substituent, an alkoxycarbonyl group which may have a substituent, a dialkylamino group which may have a substituent, a diarylamino group which may have a substituent, an arylalkylamino group which may have a substituent, an acyl group which may have a substituent, a haloalkyl group which may have a substituent, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a silyl group which may have a substituent, a siloxy group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which
  • the group represented by formula (2) preferably has two branches and a polymerizable functional group in the side chain. From this viewpoint, if R 1 in formula (2) is an alkyl group which may have a substituent, formula (2) is preferably branched at the alkyl group, and the solubility in organic solvents is further improved.
  • L 1 and L 2 each independently represent a direct bond, a divalent group, a group represented by formula (1A) below, or a group represented by formula (3A) below.
  • the solubility in organic solvents is further improved, so that at least one of L1 and L2 is preferably a group represented by the following formula (1A) or a group represented by the following formula (3A).
  • * represents a bond to any atom in formula (1) or (2).
  • B 1 and B 2 each independently represent a direct bond or a divalent group.
  • R3 represents a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, a heteroaryloxy group which may have a substituent, an alkoxycarbonyl group which may have a substituent, a dialkylamino group which may have a substituent, a diarylamino group which may have a substituent, an arylalkylamino group which may have a substituent, an acyl group which may have a substituent, a haloalkyl group which may have a substituent, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a silyl group which may have a substituent, a siloxy group which may have a substituent
  • * represents a bond to any atom in formula (1) and formula (2).
  • B 1 and B 2 each independently represent a direct bond or a divalent group.
  • the divalent group include an alkylene group, a divalent group having a ketone group, a divalent group having an ether bond, a divalent group having an ester bond, or a group formed by linking these groups.
  • n is an integer of 1 or more.
  • the compound A of the present invention is preferably a compound satisfying the following formula (I) and formula (II-1).
  • M ETM represents the molecular weight of the compound represented by the above formula (1)
  • M X represents the molecular weight of the compound in which all of the binding sites of X in the above formula (1) have been replaced with hydrogen atoms.
  • the molecular weight ( METM ) of the compound represented by formula (1) is 700 or more as in formula (I). From such viewpoints, the molecular weight ( METM ) of the compound represented by formula (1) is more preferably 750 or more, even more preferably 800 or more, even more preferably 900 or more, and particularly preferably 1000 or more. On the other hand, from the viewpoint of solubility, the molecular weight is preferably 2000 or less. Therefore, the molecular weight is preferably 1800 or less, more preferably 1600 or less, even more preferably 1500 or less, and particularly preferably 1400 or less.
  • M X /M ETM in formula (II-1), i.e., the ratio of the molecular weight of a compound in which all of the bonding sites of X in formula (1) are replaced with hydrogen atoms to the molecular weight of the compound represented by formula (1), means the ratio of structures capable of participating in the transfer of electrons in the compound. If the ratio is 0.32 or more, the structure that contributes to electron transport in the protective layer becomes high, and the electrical characteristics become better due to the high electron transport property, which is preferable. From this viewpoint, the ratio is more preferably 0.33 or more, even more preferably 0.34 or more, even more preferably 0.35 or more, and particularly preferably 0.36 or more.
  • the ratio is 0.60 or less, the ratio of the hydrophobic ⁇ -conjugated skeleton is in the preferred range, the solubility in alcohol-based solvents is increased, and the coatability of the coating solution when forming a protective layer is improved, which is preferable.
  • the ratio is more preferably 0.58 or less, even more preferably 0.56 or less, even more preferably 0.54 or less, and particularly preferably 0.53 or less.
  • the molecular weight (M x ) of the compound in which all the bonding sites of X in the formula (1) are replaced with hydrogen atoms may be any molecular weight that satisfies the above formula (II-1).
  • the molecular weight (M x ) is more preferably 250 or more, even more preferably 300 or more, even more preferably 350 or more, and particularly preferably 400 or more.
  • it is preferably 800 or less, even more preferably 750 or less, even more preferably 700 or less, and particularly preferably 650 or less.
  • the compound A of the present invention is a compound which further satisfies the following formula (IV).
  • EA X represents the electron affinity (eV) of the compound in which all the binding sites of X in the above formula (1) are replaced with hydrogen atoms. As described in the Examples below, this parameter is determined by quantum scientific calculations.
  • the electron affinity (eV) of the compound in which all the binding sites of X in formula (1) are replaced with hydrogen atoms is preferably 3.8 or more, since this improves the electron injection property from the adjacent layer and the electron transport property in the protective layer.
  • the electron affinity (EA x ) of the compound in which all the binding sites of X in formula (1) are replaced with hydrogen atoms is more preferably 3.83 or more, even more preferably 3.85 or more, even more preferably 3.89 or more, and particularly preferably 3.94 or more.
  • the electron affinity (EA x ) is 6.0 or less. Therefore, the electron affinity is preferably 5.5 or less, more preferably 5.0 or less, further preferably 4.7 or less, and particularly preferably 4.4 or less.
  • the compound A of the present invention preferably has at least one polymerizable functional group in one molecule. By having one or more polymerizable functional groups, crosslinkability is further enhanced, the hardness of the present protective layer is increased, and the mechanical strength can be further increased.
  • the compound A of the present invention may have one or more polymerizable functional groups, but from the viewpoints of solubility in an organic solvent and curability, the number of polymerizable functional groups is preferably two or more, and more preferably four or more. On the other hand, from the viewpoint of the stability of the compound, the number of polymerizable functional groups possessed by the compound A of the present invention is preferably 12 or less, more preferably 10 or less, and more preferably 8 or less.
  • the polymerizable functional group is not particularly limited as long as it is a functional group that has polymerizability, but examples include polymerizable functional groups represented by the following formulas (M1) to (M7).
  • R 110 represents a hydrogen atom or an alkyl group which may have a substituent, and * represents the bonding position.
  • R 110 in the above formulae (M1) to (M7) is preferably a hydrogen atom or an alkyl group having no substituent, more preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and particularly preferably a hydrogen atom or a methyl group.
  • compound A of the present invention has two or more polymerizable functional groups, they do not all need to be the same and may be different, but from the viewpoint of curability, it is preferable that they are the same.
  • the compound B of the present invention is preferably a compound represented by the above formula (1) and satisfying the following formulas (I) and (II-2).
  • the compound B of the present invention is preferably a compound satisfying the following formulae (I) to (III).
  • M ETM represents the molecular weight of the compound represented by formula (1).
  • M X represents the molecular weight of the compound in which all of the bonding sites of X in formula (1) have been replaced with hydrogen atoms.
  • a ETM represents the number of polymerizable functional groups contained per 1,000 molecular weight of the compound represented by formula (1).
  • the molecular weight ( METM ) of the compound represented by formula (1) is 700 or more, the amorphous property is improved and crystallization is easily suppressed, so that the film formability is improved and the film becomes uniform, resulting in good charge transport properties, which is preferable.
  • the molecular weight ( METM ) of the compound represented by formula (1) is more preferably 750 or more, even more preferably 800 or more, even more preferably 900 or more, and particularly preferably 1000 or more.
  • the molecular weight is preferably 2000 or less. Therefore, the molecular weight is preferably 1800 or less, more preferably 1600 or less, even more preferably 1500 or less, and particularly preferably 1400 or less.
  • M X /M ETM in formula (II-2), i.e., the ratio of the molecular weight of a compound in which all of the binding sites of X in formula (1) are replaced with hydrogen atoms to the molecular weight of the compound represented by formula (1), means the ratio of structures capable of participating in the transfer of electrons in the compound. If the ratio is greater than 0.31, the structure that contributes to electron transport in the protective layer is high, and the electrical properties are further improved due to the high electron transport property, which is preferable. From this viewpoint, the ratio is more preferably 0.32 or more, more preferably 0.33 or more, even more preferably 0.34 or more, even more preferably 0.35 or more, and particularly preferably 0.36 or more.
  • the ratio is 0.60 or less, the ratio of the hydrophobic ⁇ -conjugated skeleton is in the preferred range, the solubility in alcohol-based solvents is increased, and the coatability of the coating solution when forming a protective layer is improved, which is preferable.
  • the ratio is more preferably 0.58 or less, even more preferably 0.56 or less, even more preferably 0.54 or less, and particularly preferably 0.53 or less.
  • the molecular weight (M x ) of the compound in which all the bonding sites of X in the formula (1) are replaced with hydrogen atoms may be any molecular weight that satisfies the above formula (II-2).
  • the molecular weight (M x ) is more preferably 250 or more, even more preferably 300 or more, even more preferably 350 or more, and particularly preferably 400 or more.
  • it is preferably 800 or less, even more preferably 750 or less, even more preferably 700 or less, and particularly preferably 650 or less.
  • the number (A ETM ) of polymerizable functional groups contained per 1000 molecular weight of the compound represented by formula (1) is 1.8 or more, the number of polymerizable functional groups present in the protective layer is large, and a dense network structure is easily formed, resulting in good hardness and elastic deformation rate.
  • the number (A ETM ) of polymerizable functional groups is more preferably 1.9 or more, even more preferably 2.2 or more, even more preferably 2.5 or more, and particularly preferably 2.8 or more.
  • the number ( AETM ) of polymerizable functional groups contained per 1000 molecular weight of the compound represented by formula (1) is too large, the electron transport property may decrease and the residual potential may deteriorate.
  • the number ( AETM ) of polymerizable functional groups is preferably 7.0 or less, more preferably 6.0 or less, even more preferably 5.0 or less, and particularly preferably 4.0 or less.
  • compound B of the present invention is particularly preferably a compound which further satisfies the above formula (IV).
  • the compound B of the present invention preferably has at least one polymerizable functional group in one molecule.
  • the compound B of the present invention may have one or more polymerizable functional groups, but from the viewpoints of solubility in an organic solvent and curability, the number of polymerizable functional groups is preferably two or more, and more preferably four or more.
  • the number of polymerizable functional groups possessed by the compound B of the present invention is preferably 12 or less, more preferably 10 or less, and more preferably 8 or less.
  • the polymerizable functional group that compound B of the present invention can have is the same as the polymerizable functional group that compound A of the present invention can have, so the explanation of the polymerizable functional group in compound A of the present invention is also the explanation of the polymerizable functional group in compound B of the present invention.
  • Specific examples of the compounds A and B of the present invention include the following: However, the compounds A and B of the present invention are not limited to the following compounds.
  • Compounds A and B of the present invention have excellent solubility in organic solvents, particularly alcoholic solvents and mixed solvents containing alcoholic solvents, and are preferably soluble in a mixed solvent of toluene and 2-propanol (toluene 30% by mass, 2-propanol 70% by mass) at a concentration of 3% by mass or more, particularly preferably 6% by mass or more.
  • composition of the present invention contains the above-mentioned compound of the present invention, and is used as a curable composition for preparing a coating liquid for forming a protective layer of the electrophotographic photoreceptor of the present invention, as described below.
  • the present composition contains an electron transporting compound containing at least the compound of the present invention, and optionally contains a polymerizable compound not having an electron transporting skeleton, an electron donating compound, a polymerization initiator, inorganic particles, and other materials.
  • composition refers to a composition that is made up of only solid components that do not contain a solvent. Therefore, the content of each component, such as the compound of the present invention, in 100 parts by mass of the present composition described below corresponds to the content of each component in 100 parts by mass of the total mass of the protective layer formed using the present composition.
  • the total mass of the protective layer means the total mass of the protective layer after curing, that is, the total mass of the solid content in the coating liquid for forming the protective layer, which will be described later.
  • the electron transporting compound contained in the present composition includes at least the compound of the present invention, and may contain an electron transporting compound other than the compound of the present invention as necessary.
  • the present composition may contain only one type of the compound of the present invention, or may contain two or more types.
  • the composition may contain only one type, or two or more types.
  • the content of the electron transport compound in the composition is preferably 40 parts by mass or more, more preferably 50 parts by mass or more, and even more preferably 60 parts by mass or more, relative to 100 parts by mass of the total mass of the composition, while from the viewpoint of the hardness and elastic deformation rate of the protective layer, the content is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, and even more preferably 70 parts by mass or less.
  • the content of the compound of the present invention is preferably 40 parts by mass or more, more preferably 50 parts by mass or more, and even more preferably 60 parts by mass or more, and may be 100 parts by mass, relative to 100 parts by mass of the total mass of the electron transporting compounds in the composition.
  • the present composition may contain a polymerizable compound that does not have an electron transport skeleton.
  • the present protective layer described below contains a polymer of a polymerizable compound that does not have an electron transport skeleton.
  • the compound of the present invention has one or more polymerizable functional groups, and therefore can also function as a curable compound.
  • a protective layer can be formed with good curability by the method described below, but by using a polymerizable compound that does not have an electron transport skeleton in addition to the compound of the present invention, the mechanical strength of the protective layer formed can be further sufficient.
  • the polymerizable compound without an electron transport backbone may be any compound having a chain polymerizable functional group.
  • a monomer, oligomer, or polymer having a radical polymerizable functional group is preferred.
  • a curable compound having crosslinking properties, particularly a photocurable compound is preferred.
  • a curable compound having two or more radical polymerizable functional groups can be mentioned.
  • a compound having one radical polymerizable functional group can also be used in combination.
  • the radically polymerizable functional group may be either an acryloyl group (including an acryloyloxy group) or a methacryloyl group (including a methacryloyloxy group), or both of these groups.
  • curable compound having a radically polymerizable functional group examples include trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, glycerol triacrylate, tris(acryloxyethyl)isocyanurate, dipentaerythritol hexaacrylate, dimethylolpropane tetraacrylate, pentaerythritol ethoxy tetraacrylate, EO-modified phosphoric acid triacrylate, 2,2,5,5-tetrahydroxymethylcyclopentanone tetraacrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, polyethylene glycol diacrylate, and the like.
  • TMPTA trimethylolpropane triacrylate
  • trimethacrylate pentaerythritol triacrylate
  • acrylate polypropylene glycol diacrylate, polytetramethylene glycol diacrylate, EO-modified bisphenol A diacrylate, PO-modified bisphenol A diacrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, tricyclodecane dimethanol diacrylate, decanediol diacrylate, hexanediol diacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, EO-modified bisphenol A dimethacrylate, PO-modified bisphenol A dimethacrylate, tricyclodecane dimethanol dimethacrylate, decanediol dimethacrylate, hexanediol dimethacrylate, and the like.
  • examples of oligomers and polymers having an acryloyl group or a methacryloyl group include urethane acrylate, ester acrylate, acrylic acrylate, and epoxy acrylate. Among these, urethane acrylate and ester acrylate are preferred, and among these, ester acrylate is more preferred.
  • the above compounds can be used alone or in combination of two or more.
  • a preferred example of a polymerizable compound that does not have an electron transport skeleton is a polyfunctional acrylate compound that does not have an aromatic ring such as a benzene ring, as shown in the structure below.
  • a polyfunctional acrylate compound By including such a polyfunctional acrylate compound, the crosslinking property is increased, the hardness of the protective layer is increased, and the mechanical strength is increased, and in addition, the compound of the present invention can be dispersed and crystallization can be suppressed. Crystallization causes leakage current, so it is not preferred as a photoreceptor.
  • the content ratio (mass ratio) of the polymerizable compound to the electron transport compound in the present composition is preferably 1.5 or less, more preferably 1.0 or less, and even more preferably 0.75 or less from the viewpoint of electron transportability, while the content ratio (mass ratio) is preferably 0.2 or more, more preferably 0.3 or more, and even more preferably 0.4 or more from the viewpoint of hardness and elastic deformation rate of the protective layer.
  • the content of the polymerizable compound not having an electron transport skeleton in the present composition corresponds to the content of the polymer in the present protective layer described below.
  • the present composition may further contain an electron donating compound.
  • the present protective layer described below contains the electron donating compound.
  • the term “electron donating compound” refers to a compound that can donate electrons to the protective layer.
  • the term “electron donating compound” refers to a compound that can reduce the energy barrier during electron transfer in the target compound (electron transporting compound) in the protective layer by any mechanism, and can inject electrons into the target compound.
  • the mechanism may be, for example, a mechanism in which the electron donating compound directly transfers electrons to the target compound, a mechanism in which the electron donating compound and the target compound transfer electrons by forming a hydrogen bond, or a mechanism in which the electron donating compound and the target compound form a hydrogen bond to reduce the energy barrier during electron transfer, and an electron transferred from the photosensitive layer is injected into the target compound present in the protective layer.
  • electron donating compounds include compounds having structures such as triphenylmethane, acridine, amine, amidine, aniline, pyridine, xanthene, benzimidazole, guanidine, and phosphazene. Compounds that will be recognized to have such effects in the future are also included.
  • examples of electron donating compounds include compounds having structures such as triphenylmethane, acridine, amine, amidine, aniline, pyridine, xanthene, benzimidazole, guanidine, and phosphazene.
  • compounds having a benzimidazole structure or a guanidine structure are preferred from the viewpoint of stability.
  • the guanidine structure either a chain guanidine structure or a cyclic guanidine structure can be used, but from the viewpoint of stability, a cyclic guanidine structure is preferred.
  • the electron donor compound is preferably a compound having one or more heteroatoms in the molecule, and more preferably a compound having one or more nitrogen atoms (N atoms) in the molecule.
  • the number of heteroatoms in one molecule of the electron donor compound is preferably one or more, more preferably two or more, and even more preferably three or more.
  • the number of nitrogen atoms (N atoms) in one molecule of the electron donor compound is preferably one or more, more preferably two or more, and even more preferably three or more.
  • the electron donating compound is preferably a compound having one or more cyclic structures.
  • the electron donor compound is preferably an electron donor compound represented by the following formula (4) or (5).
  • These electron donor compounds are activated, for example, when heated to room temperature or higher, and can donate electrons to the protective layer.
  • the electron donor compound represented by the following formula (4) is activated when heated to about 80° C. or higher, and can donate electrons to the protective layer.
  • the electron donor compound represented by the following formula (5) is activated when heated to room temperature or higher, and can donate electrons to the protective layer.
  • these compounds are activated by the temperature rise accompanying ultraviolet irradiation, and can donate electrons to the protective layer.
  • E 1 to E 4 are each independently a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an optionally substituted thioalkyl group, an optionally substituted thioaryl group, an optionally substituted arylsulfonyl group, an optionally substituted amino group, an optionally substituted alkylamino group, an optionally substituted arylamino group, an optionally substituted hydroxy group, an optionally substituted alkoxy group, an optionally substituted acylamino group, an optionally substituted acyloxy group, an optionally substituted aromatic hydrocarbon group, an optionally substituted carboxy group, an optionally substituted carboxamido group, an optionally substituted carboalkoxy group, an optionally substituted acyl group, an optionally substituted sulfonyl group, an optionally substituted cyano group, an optionally substituted nitro group, or a derivative of any of these groups.
  • a halogen atom an optional
  • h is an integer of 0 or more, and from the viewpoint of stability, h is preferably 2 or less, more preferably 1 or less, and even more preferably 0.
  • g1 is an integer of 1 or more, and from the viewpoint of electrical properties, g1 is preferably 4 or less, more preferably 3 or less, and even more preferably 2 or less.
  • Ar is preferably represented by the following formula (6):
  • G 22 is preferably an alkyl group which may have a substituent, an alkoxy group which may have a substituent, or a halogen atom.
  • g2 is an integer of 0 or more, and from the viewpoint of stability, it is preferably 2 or less, more preferably 1 or less, and most preferably 0.
  • G21 in formula (5) is preferably a hydrocarbon group which may have a substituent.
  • the number of carbon atoms in the hydrocarbon group is preferably 1 or more, more preferably 3 or more, and is preferably 12 or less, more preferably 10 or less.
  • the hydrocarbon group is preferably an alkyl group, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a hexyl group, an octyl group, or a decyl group.
  • the hydrocarbon group is preferably an alkylene group, such as a methylene group or an ethylene group.
  • the content of the electron donor compound in the composition is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1.0 parts by mass or more, per 100 parts by mass of the total composition.
  • the content is preferably 25 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 5.0 parts by mass or less, per 100 parts by mass of the total composition.
  • the composition may contain only one of these electron donor compounds, or may contain two or more of them.
  • polymerization initiator examples include a thermal polymerization initiator and a photopolymerization initiator.
  • thermal polymerization initiator include peroxide compounds such as 2,5-dimethylhexane-2,5-dihydroperoxide, and azo compounds such as 2,2'-azobis(isobutyronitrile).
  • Photopolymerization initiators can be classified into direct cleavage type and hydrogen abstraction type depending on the radical generation mechanism.
  • Direct cleavage photopolymerization initiators generate radicals by cleaving some of the covalent bonds in the molecule when they absorb light energy
  • hydrogen abstraction photopolymerization initiators generate radicals when the molecule becomes excited by absorbing light energy and abstracts hydrogen from the hydrogen donor.
  • Direct cleavage photopolymerization initiators include, for example, acetophenone or ketal compounds such as acetophenone, 2-benzoyl-2-propanol, 1-benzoylcyclohexanol, 2,2-diethoxyacetophenone, benzyl dimethyl ketal, and 2-methyl-4'-(methylthio)-2-morpholinopropiophenone; benzoin ether compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether, benzoin isopropyl ether, and O-tosylbenzoin; and acylphosphine oxide compounds such as diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and lithium phenyl(2,4,6-trimethylbenzoyl)phosphonate.
  • Examples of the hydrogen abstraction type photopolymerization initiator include benzophenone-based compounds such as benzophenone, 4-benzoylbenzoic acid, 2-benzoylbenzoic acid, methyl 2-benzoylbenzoate, methyl benzoylformate, benzyl, p-anisil, 2-benzoylnaphthalene, 4,4'-bis(dimethylamino)benzophenone, 4,4'-dichlorobenzophenone, and 1,4-dibenzoylbenzene; and anthraquinone-based or thioxanthone-based compounds such as 2-ethylanthraquinone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, and 2,4-dichlorothioxanthone.
  • benzophenone-based compounds such as benzophenone, 4-
  • photopolymerization initiator examples include camphorquinone, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime, acridine compounds, triazine compounds, and imidazole compounds.
  • the photopolymerization initiator preferably has an absorption wavelength in the wavelength region of the light source used for light irradiation.
  • an acylphosphine oxide compound and a hydrogen abstraction initiator in combination.
  • the content ratio of the hydrogen abstraction initiator relative to the acylphosphine oxide compound is not particularly limited. From the viewpoint of supplementing the surface curability, it is preferably 0.1 parts by mass or more relative to 1 part by mass of the acylphosphine oxide compound, and from the viewpoint of maintaining the internal curability, it is preferably 5 parts by mass or less.
  • a substance that has a photopolymerization promoting effect can be used alone or in combination with the above photopolymerization initiator.
  • substances that have a photopolymerization promoting effect include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino)ethyl benzoate, and 4,4'-dimethylaminobenzophenone.
  • the polymerization initiator may be used alone or in combination of two or more.
  • the content of the polymerization initiator is 0.5 to 40 parts by mass, preferably 1 to 20 parts by mass, based on 100 parts by mass of the total content having radical polymerizability.
  • the total content having radical polymerizability includes the compound of the present invention and the polymerizable compound not having an electron transport skeleton.
  • the composition may contain inorganic particles from the viewpoint of improving the strong exposure characteristics and mechanical strength of the protective layer to be formed, or from the viewpoint of imparting charge transporting ability, although the inorganic particles are not an essential component of the composition of the present invention.
  • inorganic particles from the viewpoint of improving the strong exposure characteristics and mechanical strength of the protective layer to be formed, or from the viewpoint of imparting charge transporting ability, although the inorganic particles are not an essential component of the composition of the present invention.
  • the compound of the present invention it is possible to form a protective layer having excellent mechanical strength without the need for containing inorganic particles.
  • the inorganic particles include metal powder, metal oxide, metal fluoride, potassium titanate, and boron nitride.
  • any inorganic particles that can be used for an electrophotographic photoreceptor can be used.
  • the inorganic particles may be of one type only, or a mixture of a plurality of types of particles.
  • the composition may contain other materials other than those described above as necessary.
  • examples of other materials include stabilizers (heat stabilizers, ultraviolet absorbers, light stabilizers, antioxidants, etc.), dispersants, antistatic agents, colorants, lubricants, etc. These may be used alone or in any ratio and combination of two or more.
  • the protective layer is preferably formed from the composition described above.
  • the method for forming the protective layer using the composition will be described below.
  • the present protective layer can be formed by applying the above-mentioned present composition, i.e., a curable composition containing an electron transporting compound including the compound of the present invention, and optionally containing a polymerizable compound not having an electron transporting skeleton, an electron donating compound, a polymerization initiator, inorganic particles, and other materials, to the present photosensitive layer as a coating liquid in which the composition is dissolved in a solvent or dispersed in a dispersion medium (hereinafter also referred to as "the present protective layer-forming coating liquid"), and curing the coating liquid.
  • a curable composition containing an electron transporting compound including the compound of the present invention and optionally containing a polymerizable compound not having an electron transporting skeleton, an electron donating compound, a polymerization initiator, inorganic particles, and other materials
  • the content of the electron transport compound including the compound of the present invention in the coating liquid for forming the protective layer is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, per 100 parts by mass of the solvent, from the viewpoints of film uniformity and solubility of the protective layer.
  • the total content of the curable compounds in the coating liquid for forming a protective layer is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, relative to 100 parts by mass of the solvent, from the viewpoint of the residual potential, while it is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more, from the viewpoint of the hardness and elastic deformation rate of the protective layer.
  • the content of other components in the coating solution for forming the protective layer i.e., components other than the electron transport compound and the curable compound contained in the composition, is the same as the content of each component in the composition described above.
  • an organic solvent can be used as the solvent used in the present protective layer-forming coating liquid.
  • the organic solvent include alcohols such as methanol, ethanol, propanol, and 2-methoxyethanol; ethers such as tetrahydrofuran, 1,4-dioxane, and dimethoxyethane; esters such as methyl formate and ethyl acetate; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; aromatic hydrocarbons such as benzene, toluene, xylene, and anisole; chlorinated hydrocarbons such as dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-dichloropropane, and trichloroethylene; nitrogen-containing compounds such as n-butylamine, isopropane,
  • a mixed solvent of any combination and ratio of these solvents may also be used.
  • alcohols, ethers, aromatic hydrocarbons, and aprotic polar solvents are preferred, alcohols, ethers, and aromatic hydrocarbons are more preferred, alcohols and ethers are even more preferred, and alcohols are most preferred.
  • an organic solvent does not dissolve the electron transport compound used in the protective layer of the photoreceptor of the present invention by itself, it can be used if it can dissolve the compound by mixing it with the above-mentioned organic solvent.
  • the use of a mixed solvent can reduce coating unevenness.
  • the ratio of the solvent and solid content used in the coating solution for forming the protective layer varies depending on the coating method for the coating solution for forming the protective layer, and may be changed as appropriate so that a uniform coating film is formed in the coating method to be used.
  • the method for applying the present protective layer-forming coating solution for forming the present protective layer is not particularly limited, and examples thereof include spray coating, spiral coating, ring coating, and dip coating.
  • the coating film After forming the coating film by the above coating method, the coating film is dried. In this case, the temperature and time of drying are not important as long as necessary and sufficient drying is obtained. However, if the protective layer is applied by only air drying after applying the photosensitive layer, it is preferable to perform sufficient drying by the method described below in the method for forming the photosensitive layer.
  • the protective layer can be formed by applying the coating solution for forming the protective layer and then curing the coating solution by applying external energy to the coating solution.
  • the external energy used in this case can be heat, light, or radiation.
  • Methods for applying heat energy include heating methods using air, gases such as nitrogen, steam, or various heat media, infrared rays, and electromagnetic waves.
  • the heating can be performed from the coating surface side or the support side.
  • the heating temperature is preferably 100°C or higher and 170°C or lower.
  • UV irradiation light sources such as high-pressure mercury lamps, metal halide lamps, electrodeless lamp bulbs, and light-emitting diodes that mainly emit ultraviolet (UV) light can be used. It is also possible to select a visible light source according to the absorption wavelength of the polymerizable compound or photopolymerization initiator.
  • the light irradiation amount is preferably 10 J/cm2 or more , more preferably 15 J/cm2 or more , and even more preferably 20 J/cm2 or more .
  • the light irradiation amount is preferably 400 J/cm2 or less, more preferably 200 J/cm2 or less , and even more preferably 150 J/cm2 or less .
  • examples of radiation energy include those using electron beams (EB).
  • a heating step may be added from the viewpoint of relieving residual stress, relieving residual radicals, and improving electrical characteristics.
  • the heating temperature is preferably 60°C or higher, more preferably 100°C or higher, and is preferably 200°C or lower, more preferably 150°C or lower.
  • the thickness of the protective layer is preferably 0.5 ⁇ m or more, more preferably 1 ⁇ m or more, and from the viewpoint of electrical properties, the thickness is preferably 5 ⁇ m or less, more preferably 4 ⁇ m or less. From the same viewpoint, the thickness of the protective layer is preferably 1/50 or more of the thickness of the photosensitive layer, more preferably 1/40 or more, and even more preferably 1/30 or more, and is preferably 1/5 or less, more preferably 1/10 or less, and even more preferably 1/20 or less.
  • the photosensitive layer may be a single-layer type photosensitive layer that contains both a charge generating material and a charge transporting material in the same layer, or it may be a laminated type photosensitive layer that is separated into a charge generating layer and a charge transporting layer.
  • CGM charge generating material
  • various photoconductive materials such as inorganic photoconductive materials and organic pigments can be used.
  • organic pigments are particularly preferred, and phthalocyanine pigments and azo pigments are more preferred.
  • azo pigments When using azo pigments, various known bisazo pigments and trisazo pigments are preferably used.
  • the particle diameter of the charge generating substance is preferably 1 ⁇ m or less, more preferably 0.5 ⁇ m or less, with the lower limit being 0.01 ⁇ m or more.
  • the particle diameter of the charge generating substance means the particle diameter when contained in the photosensitive layer.
  • the amount of the charge generating material in the single-layer photosensitive layer is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more. Also, from the viewpoint of sensitivity and chargeability, the amount is preferably 50% by mass or less, and more preferably 20% by mass or less.
  • Charge transport materials are classified into hole transport materials having mainly hole transporting ability and electron transport materials having mainly electron transporting ability.
  • the present photosensitive layer is a single-layer type photosensitive layer, it is preferable that at least a hole transport material and an electron transport material are contained in the same layer.
  • the hole transport material can be selected from known materials and used, for example, electron donating materials such as heterocyclic compounds such as carbazole derivatives, indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, thiadiazole derivatives, and benzofuran derivatives, aniline derivatives, hydrazone derivatives, arylamine derivatives, stilbene derivatives, butadiene derivatives, and enamine derivatives, as well as compounds in which a plurality of these compounds are bonded, and polymers having groups made of these compounds in the main chain or side chain.
  • electron donating materials such as heterocyclic compounds such as carbazole derivatives, indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, thiadiazole derivatives, and benzofuran derivatives, aniline derivatives, hydrazone derivatives, arylamine derivatives, stilbene derivatives, butadiene derivatives, and enamine derivatives,
  • carbazole derivatives arylamine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives, and combinations of multiple types of these compounds are preferred, with arylamine derivatives and enamine derivatives being more preferred.
  • the hole transport material may be used alone or in any combination of two or more kinds in any ratio.
  • the amount of the hole transport substance in the single-layer photosensitive layer is preferably 20% by mass or more, and more preferably 30% by mass or more, relative to 100% by mass of the entire photosensitive layer. From the viewpoint of solubility, the amount is preferably 55% by mass or less, and more preferably 45% by mass or less.
  • the electron transport material (ETM) can be selected from known materials. Examples include electron-withdrawing substances such as aromatic nitro compounds such as 2,4,7-trinitrofluorenone, cyano compounds such as tetracyanoquinodimethane, and quinone compounds such as diphenoquinone, as well as known cyclic ketone compounds and perylene pigments (perylene derivatives). Among these, from the viewpoint of electrical properties, quinone compounds and perylene pigments (perylene derivatives) are preferred, and quinone compounds are more preferred. Among the quinone compounds, diphenoquinone or dinaphthylquinone is preferable from the viewpoint of electrical properties, and among them, dinaphthylquinone is more preferable.
  • the electron transport material may be used alone or in any combination of two or more kinds in any ratio.
  • ET-2 and ET-5 are preferred from the viewpoint of electrical properties, with ET-2 being even more preferred.
  • the amount of the electron transport material in the single-layer photosensitive layer is preferably 15% by mass or more, and more preferably 25% by mass or more, relative to 100% by mass of the entire photosensitive layer. From the viewpoint of solubility, the amount is preferably 40% by mass or less, and more preferably 30% by mass or less.
  • binder resin examples include vinyl polymers or copolymers thereof such as polymethyl methacrylate, polystyrene, and polyvinyl chloride; vinyl alcohol resins; polyvinyl butyral resins; polyvinyl formal resins; partially modified polyvinyl acetal resins; polyarylate resins; polyamide resins; polyurethane resins; polycarbonate resins; polyester resins; polyester carbonate resins; polyimide resins; phenoxy resins; epoxy resins; silicone resins; and partially crosslinked cured products thereof.
  • the above resins may be modified with silicon reagents or the like. These may be used alone or in any ratio and combination of two or more.
  • the binder resin used in the photosensitive layer preferably contains one or more types of polymers obtained by interfacial polymerization.
  • binder resin obtained by the above interfacial polymerization polycarbonate resin and polyester resin are preferable, and polycarbonate resin and polyarylate resin are particularly preferable.
  • polymers made from aromatic diols are particularly preferable.
  • the photosensitive layer may contain additives such as well-known antioxidants, plasticizers, ultraviolet absorbers, electron-withdrawing compounds, leveling agents, and visible light shielding agents in order to improve film-forming properties, flexibility, coating properties, contamination resistance, gas resistance, light resistance, and the like.
  • the photosensitive layer may also contain various additives such as sensitizers, dyes, pigments (excluding the above-mentioned charge generating materials, hole transport materials, and electron transport materials), and surfactants, as necessary.
  • surfactants include silicone oils and fluorine-based compounds. In the present invention, these may be used alone or in any ratio and combination of two or more of them.
  • the photosensitive layer may contain fluorine-based resins, silicone resins, etc., and may contain particles made of these resins or particles of inorganic compounds such as aluminum oxide.
  • the thickness of the present photosensitive layer is preferably 20 ⁇ m or more, more preferably 25 ⁇ m or more, from the viewpoint of dielectric breakdown resistance, and is preferably 50 ⁇ m or less, more preferably 40 ⁇ m or less, from the viewpoint of electrical properties.
  • the photoreceptor of the present invention is a laminated type photosensitive layer, for example, a structure in which a charge transport layer (CTL) containing a charge transport material is laminated on a charge generation layer (CGL) containing a charge generation material (CGM) can be mentioned.
  • CTL charge transport layer
  • CGL charge generation layer
  • CGM charge generation material
  • the charge generating layer (CGL) usually contains a charge generating material (CGM) and a binder resin.
  • the charge generating material (CGM) and the binder resin are the same as those explained in the single-layer type photosensitive layer.
  • the charge generating layer may contain other components as necessary.
  • known additives such as antioxidants, plasticizers, ultraviolet absorbers, electron-withdrawing compounds, leveling agents, visible light blocking agents, and fillers may be contained.
  • the compounding ratio (mass) of the charge generating substance is preferably 10 parts by mass or more, and more preferably 30 parts by mass or more, per 100 parts by mass of the binder resin.
  • the compounding ratio (mass) of the charge generating substance is preferably 1000 parts by mass or less, and more preferably 500 parts by mass or less, per 100 parts by mass of the binder resin. From the viewpoint of film strength, a ratio of 300 parts by mass or less is even more preferable, and 200 parts by mass or less is particularly preferable.
  • the thickness of the charge generating layer is preferably 0.1 ⁇ m or more, more preferably 0.15 ⁇ m or more. On the other hand, it is preferably 10 ⁇ m or less, more preferably 0.6 ⁇ m or less.
  • the charge transport layer (CTL) usually contains a charge transport material and a binder resin.
  • the charge transport material and the binder resin are the same as those explained in the single-layer type photosensitive layer.
  • the mixing ratio of the hole transport material (HTM) to the binder resin is preferably 20 parts by mass or more per 100 parts by mass of the binder resin, more preferably 30 parts by mass or more from the viewpoint of reducing the residual potential, and even more preferably 40 parts by mass or more from the viewpoint of stability and charge mobility during repeated use.
  • the blending ratio of the electron transport material (ETM) to the binder resin is preferably 20 parts by mass or more per 100 parts by mass of the binder resin, more preferably 30 parts by mass or more from the viewpoint of reducing the residual potential, and even more preferably 40 parts by mass or more from the viewpoint of stability and charge mobility during repeated use.
  • the charge transport layer may contain other components as necessary in addition to the electron transport material (ETM), hole transport material (HTM) and binder resin.
  • ETM electron transport material
  • HTM hole transport material
  • binder resin may contain additives such as known antioxidants, plasticizers, UV absorbers, electron-withdrawing compounds, leveling agents, visible light shielding agents and fillers for the purpose of improving film-forming properties, flexibility, coatability, stain resistance, gas resistance, light resistance, etc.
  • the thickness of the charge transport layer is not particularly limited. From the viewpoints of electrical characteristics, image stability, and high resolution, it is preferably 5 ⁇ m or more and 50 ⁇ m or less, more preferably 10 ⁇ m or more and 40 ⁇ m or less, and even more preferably 15 ⁇ m or more and 35 ⁇ m or less.
  • the above layers can be formed as follows.
  • the substance to be contained is dissolved or dispersed in a solvent to obtain a coating solution, which is then applied to a conductive support by a known method such as dip coating, spray coating, nozzle coating, bar coating, roll coating, or blade coating, and the layers are then coated and dried in sequence to form a layer.
  • a known method such as dip coating, spray coating, nozzle coating, bar coating, roll coating, or blade coating
  • the layers are then coated and dried in sequence to form a layer.
  • the method is not limited to this.
  • solvent or dispersion medium used to prepare the coating liquid.
  • Specific examples include alcohols, ethers, aromatic hydrocarbons, and chlorinated hydrocarbons. These may be used alone or in any combination of two or more of any type.
  • the amount of the solvent or dispersion medium used is not particularly limited. Taking into consideration the purpose of each layer and the properties of the selected solvent or dispersion medium, it is preferable to appropriately adjust the solid content concentration, viscosity, and other physical properties of the coating liquid so that they fall within the desired range.
  • the coating film is preferably dried to the touch at room temperature, and then heated and dried for 1 minute to 2 hours at a temperature in the range of 30° C. to 200° C., either stationary or with a fan.
  • the heating temperature may be constant, or the temperature may be changed during drying.
  • the conductive support of the photoreceptor of the present invention (hereinafter also referred to as the "conductive support”) is not particularly limited as long as it supports a layer formed thereon and exhibits electrical conductivity.
  • the conductive support that can be used include metal materials such as aluminum, aluminum alloys, stainless steel, copper, and nickel; resin materials to which electrical conductivity has been imparted by the coexistence of conductive powders such as metal, carbon, and tin oxide; and resins, glass, and paper to which a conductive material such as aluminum, nickel, or ITO (indium oxide tin oxide alloy) has been vapor-deposited or applied on the surface.
  • the conductive support may be in the form of a drum, cylinder, sheet, belt, or the like.
  • the conductive support may be a conductive support made of a metal material on which a conductive material having an appropriate resistance value is applied in order to control the conductivity and surface properties or to cover defects.
  • the metal material When a metal material such as an aluminum alloy is used as the conductive support, the metal material may be provided with an anodized coating before use.
  • the average thickness of the anodic oxide coating is preferably 20 ⁇ m or less, and more preferably 7 ⁇ m or less.
  • the surface of the conductive support may be smooth, or may be roughened by using a special cutting method or by polishing. It may also be roughened by mixing particles of an appropriate particle size into the material that constitutes the support.
  • the photoreceptor of the present invention may have an undercoat layer (also referred to as "subsequent undercoat layer”) between the present conductive substrate and the present photosensitive layer in order to improve adhesion, blocking properties, and the like.
  • an undercoat layer also referred to as "subsequent undercoat layer”
  • the undercoat layer may be, for example, a resin or a resin in which organic pigments or particles of metal oxides are dispersed.
  • the undercoat layer may also contain known antioxidants.
  • organic pigments used in the undercoat layer include phthalocyanine pigments, azo pigments, and perylene pigments. Among them, phthalocyanine pigments and azo pigments, specifically, the phthalocyanine pigments and azo pigments used as the charge generating material described above, can be mentioned.
  • metal oxide particles used in the undercoat layer include metal oxide particles containing one type of metal element, such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, and iron oxide, and metal oxide particles containing multiple metal elements, such as calcium titanate, strontium titanate, and barium titanate.
  • the undercoat layer may contain only one type of particle, or multiple types of particles may be mixed in any ratio and combination.
  • titanium oxide and aluminum oxide are preferred, with titanium oxide being particularly preferred.
  • the particle size of the metal oxide particles used in this undercoat layer is not particularly limited.
  • the average primary particle size is preferably 10 nm or more, while it is preferably 100 nm or less, and more preferably 50 nm or less.
  • the binder resin used in the present undercoat layer may be selected from, for example, polyvinyl acetal resins such as polyvinyl butyral resins; insulating resins such as polyarylate resins, polycarbonate resins, polyester resins, phenoxy resins, acrylic resins, methacrylic resins, polyamide resins, polyurethane resins, epoxy resins, silicone resins, polyvinyl alcohol resins, and styrene-alkyd resins.
  • the binder resin is not limited to these polymers. These binder resins may be used alone or in combination of two or more kinds, or may be used in a cured form together with a curing agent.
  • polyvinyl acetal resins preferred because they exhibit good dispersibility and coatability, and among these, alcohol-soluble copolymerized polyamides are particularly preferred.
  • the mixing ratio of the particles to the binder resin can be selected as desired, but it is preferable to use a ratio in the range of 10% by mass to 500% by mass in terms of the stability and coatability of the dispersion.
  • this undercoat layer can be selected as desired. In view of the characteristics of the electrophotographic photoreceptor and the coatability of the dispersion liquid, it is preferably 0.1 ⁇ m or more, and more preferably 20 ⁇ m or less.
  • the photoreceptor of the present invention may have other layers, if necessary, in addition to the conductive substrate, photosensitive layer, protective layer and undercoat layer described above.
  • the photoreceptor of the present invention may have the following physical properties.
  • the Martens hardness varies depending on the component composition of the protective layer, but is preferably 175 N/ mm2 or more, more preferably 200 N/mm2 or more , and even more preferably 220 N/ mm2 or more.
  • the Martens hardness of the photoreceptor means the Martens hardness measured from the surface side of the photoreceptor. The Martens hardness can be measured by the method described in the Examples below.
  • the elastic deformation rate of the photoreceptor means the elastic deformation rate measured from the surface side of the photoreceptor.
  • the elastic deformation rate can be measured by the method described in the Examples below.
  • the residual potential in the photoreceptor of the present invention, is preferably 250 V or less, more preferably 200 V or less, even more preferably 150 V or less, and even more preferably 100 V or less.
  • the residual potential of the photoconductor means the potential of the photoconductor after it has been charged and irradiated with exposure light. The residual potential can be measured by the method described in the Examples below.
  • Image forming apparatus of the present invention An image forming apparatus (hereinafter, also referred to as "image forming apparatus of the present invention") can be constructed using the photoreceptor of the present invention.
  • image forming apparatus of the present invention described below is one example of an image forming apparatus that can be constructed using the present electrophotographic photoreceptor.
  • the image forming apparatus of the present invention is configured with the photoreceptor 1 of the present invention, a charging device 2, an exposure device 3, and a developing device 4, and may further include a transfer device 5, a cleaning device 6, and a fixing device 7 as necessary.
  • the photoreceptor 1 of the present invention is not particularly limited as long as it is the photoreceptor of the present invention described above.
  • FIG. 1 shows a drum-shaped photoreceptor in which the above-mentioned photosensitive layer is formed on the surface of a cylindrical conductive support.
  • a charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are arranged along the outer circumferential surface of the photoreceptor 1 of the present invention.
  • the charging device 2 may be a non-contact corona charging device such as a corotron or scorotron, or a contact-type charging device (direct-type charging device) that charges the photoconductor surface by contacting a charging member to which a voltage is applied.
  • Examples of contact charging devices include a charging roller and a charging brush. Note that FIG. 1 shows a roller-type charging device (charging roller) as an example of the charging device 2.
  • the exposure device 3 is not particularly limited in type as long as it can expose the photoreceptor 1 of the present invention to light and form an electrostatic latent image on the photosensitive surface of the photoreceptor 1 of the present invention. Moreover, the exposure may be performed by an internal exposure method of the photoconductor.
  • the type of toner T is arbitrary, and in addition to powder toner, polymerized toner produced using methods such as suspension polymerization and emulsion polymerization can be used.
  • the configuration of the developing device 4 is also arbitrary.
  • the developing device 4 shown in Fig. 1 has a configuration in which the toner T is made into a thin layer by a regulating member (developing blade) 45, is triboelectrically charged to a predetermined polarity, and is carried by a developing roller 44 while being transported to contact the surface of the photoconductor 1.
  • the configuration is not limited to this.
  • the type of the transfer device 5 is not particularly limited, and any device using any method, such as electrostatic transfer methods such as corona transfer, roller transfer, and belt transfer, pressure transfer, and adhesive transfer, can be used.
  • the cleaning device 6 There is no particular limitation on the cleaning device 6.
  • any cleaning device can be used, such as a brush cleaner, a magnetic roller cleaner, a blade cleaner, etc. If there is little or almost no toner remaining on the photoreceptor surface, the cleaning device 6 may not be necessary.
  • the fixing device 7 may also have any configuration.
  • the image forming apparatus may be configured to perform, for example, a charge removal process.
  • the image forming device may be further modified, for example, to perform processes such as a pre-exposure process and an auxiliary charging process, to perform offset printing, or even to be configured as a full-color tandem system using multiple types of toner.
  • the photoreceptor 1 of the present invention can be combined with one or more of a charging device 2, an exposure device 3, a developing device 4, a transfer device 5, a cleaning device 6 and a fixing device 7 to form an integrated cartridge (referred to as the "cartridge of the present invention").
  • a charging device 2 an exposure device 3
  • a developing device 4 a transfer device 5
  • a cleaning device 6 a cleaning device 6
  • a fixing device 7 to form an integrated cartridge
  • the cartridge of the present invention described below is one example of an electrophotographic cartridge that can be constructed using the present electrophotographic photoreceptor.
  • the cartridge of the present invention can be configured to be detachable from the main body of an electrophotographic device such as a copying machine or a laser beam printer.
  • an electrophotographic device such as a copying machine or a laser beam printer.
  • the electrophotographic photoreceptor cartridge can be removed from the main body of the image forming device and a new electrophotographic photoreceptor cartridge can be attached to the main body of the image forming device, making it easy to maintain and manage the image forming device.
  • DMF means N,N-dimethylformamide
  • NMP means N-methyl-2-pyrrolidone
  • Et means ethyl group
  • Ac means acetyl group
  • MEHQ means 4-methoxyphenol
  • Non-Patent Document 1 Organic Letters, 2010, Vol. 12, No. 10, 2382-2385
  • the “electron affinity of the compound” is a value obtained using the software “Spartan'18 Parallel Suite” (Wavefunction, Inc.).
  • the calculation method of the electron affinity of the compound will be described below.
  • geometry optimization was performed using the density functional (DFT) method (functional “B3LYP", basis function "6-31G * ").
  • DFT density functional
  • E LUMO /eV lowest unoccupied molecular orbital
  • EA X (eV) -0.8059 ⁇ E LUMO +1.1451
  • ⁇ Completely dissolved at room temperature. A: A small amount of undissolved material was observed at room temperature, but the material was completely dissolved when heated at 40° C. for less than 10 minutes. ⁇ : Some residue remained at room temperature, but was completely dissolved when heated at 40° C. for 10 minutes or more. x: Even after heating at 40° C. for 10 minutes or more, some of the material remained undissolved.
  • ⁇ Preparation of Coating Solution Q1 for Forming Single-Layer Photosensitive Layer> 2.6 parts of D-type titanyl phthalocyanine showing a clear peak at a diffraction angle 2 ⁇ 27.3° ⁇ 0.2° in powder X-ray diffraction using CuK ⁇ radiation, 11.3 parts of a perylene pigment having the following structure, 0.5 parts of a polyvinyl butyral resin, 90 parts of the following hole transport material (HTM48, molecular weight 748), 70 parts of the following electron transport material (ET-2, molecular weight 424.2), 100 parts of a polycarbonate resin having a biphenyl structure, 0.05 parts of a silicone oil (manufactured by Shin-Etsu Silicones: product name KF-96) as a leveling agent, and 793.35 parts of a mixed solvent of tetrahydrofuran (hereinafter appropriately abbreviated as THF) and toluene (hereinafter appropriately abbreviated as TL) (TH
  • Curable compound A-DPH (dipentaerythritol polyacrylate, product name "NK Ester A-DPH”, manufactured by Shin-Nakamura Chemical Co., Ltd.)
  • Electron donor compound N-DMBI (N,N-dimethylbenzylamine, manufactured by Tokyo Chemical Industry Co., Ltd.)
  • Example 1 to 5 In Examples 1 to 5 and Comparative Examples 1 to 7, single-layer photoreceptors A1 to A12 were prepared as shown in Table 2 and evaluated.
  • the coating solutions S1 to S14 for forming a protective layer were each ring-coated on the single-layer photosensitive layer, and immediately after coating, the photoreceptor was rotated at 60 rpm under a nitrogen atmosphere, and 365 nm LED light was irradiated with an intensity of 0.9 W/cm 2 for 30 seconds for photoreceptor 2, 60 seconds for photoreceptors 1, 4, and 7, and 2 minutes for photoreceptors 3, 5, 6, and 8 to 12 to provide a protective layer so that the film thickness after curing was 1.5 to 2.0 ⁇ m, respectively, to produce photoreceptors A1 to A12.
  • the obtained photoreceptors A1 to A12 were measured from the surface side of the photoreceptor using a microhardness tester (Fischer: FISCHERSCOPE HM2000) under an environment of a temperature of 25° C. and a relative humidity of 50% under the following measurement conditions.
  • a microhardness tester Fischer: FISCHERSCOPE HM2000
  • the elastic deformation rate is a value defined by the following formula, and is the ratio of the work performed by the membrane due to its elasticity when removing the load to the total work required for pressing.
  • Elastic deformation rate (%) (We / Wt) x 100
  • the total work load Wt (nJ) represents the area surrounded by A-B-D-A in Fig. 2
  • the elastic deformation work load We (nJ) represents the area surrounded by C-B-D-C.
  • the larger the elastic deformation rate the less likely deformation will remain in response to the load, and an elastic deformation rate of 100 means that no deformation will remain.
  • a Martens hardness (shown as “hardness” in Table 2) of 200 N/mm2 or more was considered “passable,” and an elastic deformation rate of 30% or more was considered “passable.”
  • the obtained photoreceptors A1 to A12 were mounted on an electrophotographic property evaluation device manufactured in accordance with the measurement standard of the Society of Electrophotography (described in "Continued Fundamentals and Applications of Electrophotographic Technology," edited by the Society of Electrophotography, Corona Publishing, pp. 404-405), and the electrical properties were measured by a cycle of charging, exposure, potential measurement, and static elimination as follows. First, the grid voltage was adjusted to charge the photoconductor so that the initial surface potential (V0) was +700 V. Next, exposure light was irradiated at 1.3 ⁇ J/cm2, and the residual potential (VL) 60 milliseconds after irradiation was measured.
  • the exposure light used was a halogen lamp light converted to monochromatic light of 780 nm using an interference filter.
  • the measurement was performed in an environment of 25° C. and 50% relative humidity (N/N environment). The smaller the absolute value of the residual potential (V), the better the result, since it means that the charge has been transported sufficiently to lower the potential. In the present invention, a residual potential of 180 V or less was deemed to be "pass.”
  • M ETM represents the molecular weight of the compound represented by formula (1).
  • M X represents the molecular weight of the compound in which all of the binding sites of X in formula (1) have been replaced with hydrogen atoms.
  • the compound forming the protective layer has an electron transporting structure, charge injection from the photosensitive layer to the protective layer and charge mobility to the outermost surface are enhanced through the electron transporting skeleton, making it possible to obtain an electrophotographic photoreceptor having excellent electrical properties such as residual potential characteristics. Furthermore, if the compound has a polymerizable functional group, the compound is polymerized in the step of forming the protective layer to form a polymer, making it possible to form a protective layer having excellent mechanical strength.
  • the compound is equal to or more than the lower limit of formula (II-1) below, the structure that contributes to electron transport present in the protective layer is high, and the high electron transport property is believed to further improve the electrical properties.
  • M ETM represents the molecular weight of the compound represented by formula (1).
  • M X represents the molecular weight of the compound in which all the bonding sites of X in formula (1) are replaced with hydrogen atoms.
  • a ETM represents the number of polymerizable functional groups contained per 1,000 molecular weight of the compound represented by formula (1).
  • the compound forming the protective layer has an electron transport structure
  • charge injection from the photosensitive layer to the protective layer and charge mobility to the outermost surface can be enhanced through the electron transport skeleton, making it possible to obtain an electrophotographic photoreceptor with excellent electrical properties such as residual potential characteristics.
  • the compound B has a polymerizable functional group, it is polymerized in the step of forming the protective layer to form a polymer, making it possible to form a protective layer having excellent mechanical strength.
  • the compound B satisfies formula (I) and formula (II-2), the proportion of structures that are thought to contribute to electron transport in the protective layer increases, which is considered to be advantageous for electron transport.Furthermore, if the compound B satisfies formula (III), the number of polymerizable functional groups present in the protective layer increases, making it easier to form a dense network structure, which is considered to result in further improved hardness and elastic deformation rate.
  • EA X represents the electron affinity (eV) of the compound in which all the binding sites of X in formula (1) are replaced with hydrogen atoms.
  • Photoconductor electrostatic photoconductor
  • Charging device Charging roller; charging section
  • Exposure device Exposure section
  • Developing device developing section
  • Transfer device 6
  • Cleaning device 7
  • Fixing device 41
  • Developer tank 42
  • Agitator 43
  • Supply roller 44
  • Development roller 45
  • Regulating member 71
  • Upper fixing member pressure roller
  • Lower fixing member fixing roller
  • Heating device T
  • Toner P Recording paper paper, medium

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JP2022540305A (ja) * 2019-07-18 2022-09-15 エルジー・ケム・リミテッド 化合物、これを含む感光性蛍光樹脂組成物、これから製造された色変換フィルム、バックライトユニットおよびディスプレイ装置
WO2023190691A1 (ja) * 2022-03-30 2023-10-05 三菱ケミカル株式会社 電子写真感光体、電子写真感光体カートリッジ及び画像形成装置
WO2023190690A1 (ja) * 2022-03-30 2023-10-05 三菱ケミカル株式会社 電子写真感光体、電子写真感光体カートリッジ及び画像形成装置、化合物

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