JP2022018811A - Cyano group-containing compounds and xerographic photoreceptor - Google Patents

Abstract

To provide compounds that improve sensitivity characteristics of a xerographic photoreceptor when contained in a photosensitive layer.SOLUTION: For example, the compounds in the figure are provided.SELECTED DRAWING: Figure 1

Description

The present invention relates to compounds (more specifically, cyano group-containing compounds) and electrophotographic photosensitive members.

The electrophotographic photosensitive member is used in an electrophotographic image forming apparatus. As the electrophotographic photosensitive member, for example, a laminated electrophotographic photosensitive member or a single-layer electrophotographic photosensitive member is used. The laminated electrophotographic photosensitive member includes, as a photosensitive layer, a charge generation layer having a charge generation function and a charge transport layer having a charge transport function. The single-layer electrophotographic photosensitive member includes, as a photosensitive layer, a single-layer photosensitive layer having a function of generating charges and a function of transporting charges.

The photosensitive layer included in the electrophotographic photosensitive member described in Patent Document 1 contains a bis (dicyanomethylene) dihydrobenzodithiophene derivative represented by the chemical formula (E-1).

Japanese Unexamined Patent Publication No. 2011-154226

However, it has been found by the study of the present inventor that the electrophotographic photosensitive member described in Patent Document 1 has room for improvement in terms of sensitivity characteristics.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a compound that improves the sensitivity characteristics of an electrophotographic photosensitive member when it is contained in a photosensitive layer. Another object of the present invention is to provide an electrophotographic photosensitive member having excellent sensitivity characteristics.

The compound of the present invention is represented by the general formula (1).

In the general formula (1), X ¹ and X ² independently represent an oxygen atom or a sulfur atom, respectively. Y represents a divalent group represented by the general formula (Y1) or (Y2).

R ¹ in the general formula (Y1) and R ² in the general formula (Y2) may be independently substituted with an alkyl group having 1 or more and 10 or less carbon atoms, and may have 6 or more carbon atoms and 22 carbon atoms. The following aryl groups, alkyl groups with 1 to 8 carbon atoms, aralkyl groups with 7 to 20 carbon atoms, cycloalkyl groups with 3 to 20 carbon atoms, alkoxy groups with 1 to 6 carbon atoms, Represents a halogen atom, a cyano group, or an -CO-OR ³ group. R ³ represents an alkyl group having 1 or more carbon atoms and 8 or less carbon atoms. M in the general formula (Y1) represents an integer of 0 or more and 4 or less. N in the general formula (Y2) represents an integer of 0 or more and 6 or less. * In the general formulas (Y1) and (Y2) represents a bond.

The electrophotographic photosensitive member of the present invention includes a conductive substrate and a photosensitive layer. The photosensitive layer is a single layer. The photosensitive layer contains a charge generator and the compound.

When the compound of the present invention is contained in the photosensitive layer, the sensitivity characteristics of the electrophotographic photosensitive member can be improved. Further, the electrophotographic photosensitive member of the present invention has excellent sensitivity characteristics.

It is a partial cross-sectional view which shows an example of the structure of the electrophotographic photosensitive member which concerns on 2nd Embodiment of this invention. It is a partial cross-sectional view which shows an example of the structure of the electrophotographic photosensitive member which concerns on 2nd Embodiment of this invention. It is a partial cross-sectional view which shows an example of the structure of the electrophotographic photosensitive member which concerns on 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. The present invention can be carried out with appropriate modifications within the scope of the object of the present invention. The description may be omitted as appropriate for the parts where the explanations are duplicated, but the gist of the invention is not limited.

Hereinafter, the compound and its derivatives may be collectively referred to by adding "system" after the compound name. Further, when the polymer name is represented by adding "system" after the compound name, it means that the repeating unit of the polymer is derived from the compound or its derivative. Further, in the general formula and the chemical formula, "-t-Bu" represents a tert-butyl group, "-COOEt" represents an ethoxycarbonyl group, and "-TMS" represents a trimethylsilyl group.

Next, the definition of the substituent used in the present specification will be described. Examples of the halogen atom (halogen group) include a fluorine atom (fluoro group), a chlorine atom (chloro group), a bromine atom (bromo group) and an iodine atom (iodine group).

Alkyl group with 1 to 10 carbon atoms, alkyl group with 1 to 8 carbon atoms, alkyl group with 1 to 6 carbon atoms, alkyl group with 1 to 4 carbon atoms, 1 to 3 carbon atoms Unless otherwise specified, the following alkyl groups and alkyl groups having 4 or more and 8 or less carbon atoms are linear or branched and unsubstituted. Examples of the alkyl group having 1 or more and 10 or less carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, and an n-pentyl group, and 1 -Methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylpropyl group, 2-ethylpropyl group, 1,1-dimethylpropyl group, 1,2-dimethylpropyl group, 2,2-dimethylpropyl group, n-hexyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, 1,1-dimethylbutyl group, 1,2-dimethylbutyl group, 1,3-dimethyl Butyl group, 2,2-dimethylbutyl group, 2,3-dimethylbutyl group, 3,3-dimethylbutyl group, 1,1,2-trimethylpropyl group, 1,2,2-trimethylpropyl group, 1-ethylbutyl Group, 2-ethylbutyl group, 3-ethylbutyl group, linear and branched heptyl group, linear and branched octyl group, linear and branched nonyl group, and direct Examples thereof include chain-shaped and branched decyl groups. Alkyl groups with 1 to 8 carbon atoms, alkyl groups with 1 to 6 carbon atoms, alkyl groups with 1 to 4 carbon atoms, alkyl groups with 1 to 3 carbon atoms, and 4 or more carbon atoms. An example of an alkyl group having 8 or less is a group having a corresponding carbon atom number among the groups described as an example of an alkyl group having 1 or more and 10 or less carbon atoms.

Unless otherwise specified, the alkoxy group having 1 or more and 6 or less carbon atoms and the alkoxy group having 1 or more and 3 or less carbon atoms are linear or branched and unsubstituted. Examples of the alkoxy group having 1 or more and 6 or less carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group and an n-pentoxy group. 1-methylbutoxy group, 2-methylbutoxy group, 3-methylbutoxy group, 1-ethylpropoxy group, 2-ethylpropoxy group, 1,1-dimethylpropoxy group, 1,2-dimethylpropoxy group, 2,2- Dimethylpropoxy group, n-hexyloxy group, 1-methylpentyloxy group, 2-methylpentyloxy group, 3-methylpentyloxy group, 4-methylpentyloxy group, 1,1-dimethylbutoxy group, 1,2- Dimethylbutoxy group, 1,3-dimethylbutoxy group, 2,2-dimethylbutoxy group, 2,3-dimethylbutoxy group, 3,3-dimethylbutoxy group, 1,1,2-trimethylpropoxy group, 1,2, Examples thereof include a 2-trimethylpropoxy group, a 1-ethylbutoxy group, a 2-ethylbutoxy group, and a 3-ethylbutoxy group. An example of an alkoxy group having 1 or more and 3 or less carbon atoms is a group having a corresponding carbon atom number among the groups described as an example of an alkoxy group having 1 or more and 6 or less carbon atoms.

Aryl groups having 6 to 22 carbon atoms, aryl groups having 6 to 14 carbon atoms, and aryl groups having 6 to 10 carbon atoms are unsubstituted unless otherwise specified. Examples of the aryl group having 6 or more and 22 or less carbon atoms include a phenyl group, a naphthyl group, an indasenyl group, a biphenylenyl group, an acenaphthylenyl group, an anthryl group and a phenanthryl group, a tetrasenyl group, a tetraphenyl group, a chrysenyl group, a pyrenyl group and a triphenylenyl group. Examples include a group, a benzophenanthrenyl group, a pisenyl group, a peryleneyl group, and a pentaphenyl group. Examples of the aryl group having 6 or more carbon atoms and 14 or less carbon atoms include a phenyl group, a naphthyl group, an indasenyl group, a biphenylenyl group, an acenaphthylenyl group, an anthryl group, and a phenanthryl group. Examples of the aryl group having 6 or more and 10 or less carbon atoms include a phenyl group and a naphthyl group.

Unless otherwise specified, cycloalkyl groups having 3 or more and 20 or less carbon atoms and cycloalkyl groups having 3 or more and 10 or less carbon atoms are unsubstituted. Examples of the cycloalkyl group having 3 or more and 20 or less carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, a cycloundesyl group and a cyclododecyl group. Examples thereof include a group, a cyclotridecyl group, a cyclotetradecyl group, a cyclopentadecyl group, a cyclohexadecyl group, a cycloheptadecyl group, a cyclooctadecyl group, a cyclononadesyl group, and a cycloicosanyl group. An example of a cycloalkyl group having 3 or more and 10 or less carbon atoms is a group having a corresponding carbon atom number among the groups described as an example of a cycloalkyl group having 3 or more and 20 or less carbon atoms.

Aralkyl groups having 7 or more and 20 or less carbon atoms are unsubstituted unless otherwise specified. Examples of the aralkyl group having 7 or more and 20 or less carbon atoms include an alkyl group having 1 or more and 6 or less carbon atoms substituted with an aryl group having 6 or more and 14 or less carbon atoms. The definition of the substituent used in the present specification has been described above.

<First Embodiment: Compound>
The first embodiment relates to a compound (more specifically, a cyano group-containing compound). The compound according to the first embodiment is represented by the general formula (1). Hereinafter, the compound represented by the general formula (1) may be referred to as compound (1).

In the general formula (1), X ¹ and X ² independently represent an oxygen atom or a sulfur atom, respectively. Y represents a divalent group represented by the general formula (Y1) or (Y2).

R ¹ in the general formula (Y1) and R ² in the general formula (Y2) may be independently substituted with an alkyl group having 1 or more and 10 or less carbon atoms, and have 6 or more and 22 or less carbon atoms. Alkyl group, alkyl group with 1 to 8 carbon atoms, aralkyl group with 7 to 20 carbon atoms, cycloalkyl group with 3 to 20 carbon atoms, alkoxy group with 1 to 6 carbon atoms, halogen atom , Cyano group, or -CO-OR ³ group (that is, a group represented by the general formula -CO-OR ³ ). R ³ in the general formula −CO—OR ³ represents an alkyl group having 1 or more carbon atoms and 8 or less carbon atoms. M in the general formula (Y1) represents an integer of 0 or more and 4 or less. N in the general formula (Y2) represents an integer of 0 or more and 6 or less. * In the general formulas (Y1) and (Y2) represents a bond.

When the compound (1) is contained in the photosensitive layer, the sensitivity characteristics of the electrophotographic photosensitive member (hereinafter, may be referred to as a photosensitive member) can be improved. The reason is presumed as follows.

Compound (1) has a broad conjugated planar structure such as a tetra-ring or penta-ring fused ring. Therefore, the transportability of electrons by the compound (1) is improved, and the sensitivity characteristics of the photoconductor can be improved.

Furthermore, compound (1) has two cyanoimino groups, which are electron accepting groups. Therefore, the electron acceptability of the compound (1) can be improved, and the sensitivity of the photoconductor can be improved. Specifically, one of the four or pentacyclic fused rings in common has two cyanoimino groups. The line symmetry of compound (1) is low with respect to the line passing through the two cyanoimino groups. The low line symmetry improves the solubility of the compound (1) in the solvent for forming the photosensitive layer. Further, the low linear symmetry improves the compatibility of the compound (1) with the binder resin. By improving the solubility and compatibility, a uniform photosensitive layer can be formed, and the sensitivity characteristics of the photoconductor can be improved.

When Y in the general formula (1) represents a divalent group represented by the general formula (Y1), the general formula (1) is represented by the following general formula (1-Y1). When Y in the general formula (1) represents a divalent group represented by the general formula (Y2), the general formula (1) is represented by the following general formula (1-Y2). X ^{1 and X 2 in the general formulas (1-Y1) and (1-Y2) are synonymous with X 1 and X 2 in the} general formula (1), respectively. R1 and m in the general formula ( ¹ -Y1) are synonymous with ^R1 and m in the general formula (Y1). R ^{2 and n in the general formula (1-Y2) are synonymous with R 2 and} n in the general formula (Y2).

As the aryl group having 6 or more and 22 or less carbon atoms represented by R ¹ in the general formula (Y1) and R ² in the general formula (Y2), an aryl group having 6 or more and 10 or less carbon atoms is preferable, and a phenyl group. Is more preferable. Aryl groups having 6 or more and 22 or less carbon atoms may be substituted with alkyl groups having 1 or more and 10 or less carbon atoms. As such an alkyl group having 1 or more and 10 or less carbon atoms, an alkyl group having 1 or more and 6 or less carbon atoms is preferable, and an alkyl group having 1 or more and 3 or less carbon atoms is more preferable.

As the alkyl group having 1 or more and 8 or less carbon atoms represented by R ¹ and R ² , an alkyl group having 1 or more and 3 or less carbon atoms or an alkyl group having 4 or more and 8 or less carbon atoms is preferable. As the alkyl group having 1 or more and 3 or less carbon atoms, a methyl group is preferable. As the alkyl group having 4 or more and 8 or less carbon atoms, a tert-butyl group is preferable.

As the aralkyl group having 7 or more and 20 or less carbon atoms represented by R ¹ and R ² , an alkyl group having 1 or more and 6 or less carbon atoms substituted with an aryl group having 6 or more and 14 or less carbon atoms is preferable. Alkyl groups having 1 to 3 carbon atoms substituted with 6 or more and 10 or less aryl groups are more preferable, and benzyl groups are even more preferable.

As the cycloalkyl group having 3 or more and 20 or less carbon atoms represented by R ¹ and R ² , a cycloalkyl group having 3 or more and 10 or less carbon atoms is preferable.

As the alkoxy group represented by R ¹ and R ² having 1 or more and 6 or less carbon atoms, an alkoxy group having 1 or more and 3 or less carbon atoms is preferable.

As the halogen atom represented by R ¹ and R ² , a fluorine atom, a chlorine atom or a bromine atom is preferable, a fluorine atom or a chlorine atom is more preferable, and a fluorine atom is particularly preferable.

As the alkyl group having 1 or more and 8 or less carbon atoms represented by R ³ in the general formula −CO—OR ³ , an alkyl group having 1 or more and 3 or less carbon atoms is preferable, and an ethyl group is more preferable.

M in the general formula (Y1) preferably represents an integer of 0 or more and 2 or less, and more preferably 1 or 2. When m represents an integer of 2 or more and 4 or less, a plurality of R ^1s may represent the same group or different groups.

N in the general formula (Y2) preferably represents an integer of 0 or more and 2 or less, and more preferably 0. When n represents an integer of 2 or more and 6 or less, the plurality of R ^2s may represent the same group or different groups.

In the general formula (Y1), one of the two * represents a bond that binds to X ¹ in the general formula (1), and the other represents a bond that binds to X ² in the general formula (1). show. In the general formula (Y2), one of the two * represents a bond that binds to X ¹ in the general formula (1), and the other represents a bond that binds to X ² in the general formula (1). show.

In order to improve the sensitivity characteristics of the photoconductor, R ¹ in the general formula (Y1) and R ² in the general formula (Y2) are independently alkyl groups and halogen atoms having 1 or more and 8 or less carbon atoms. , Cyano group, or -CO-OR ³ group is preferable. R ³ preferably represents an alkyl group having 1 or more and 8 or less carbon atoms.

Y in the general formula (1) represents a divalent group represented by the general formula (Y1), and R ¹ in the general formula (Y1) represents an alkyl group having 4 or more and 8 or less carbon atoms. Is preferable. When R ¹ represents a lipophilic alkyl group having 4 or more and 8 or less carbon atoms, the solubility of the compound (1) in the solvent for forming the photosensitive layer is further improved. Further, when R ¹ represents an alkyl group having 4 or more and 8 or less carbon atoms, which is relatively bulky, the symmetry of the compound (1) is further lowered. For these reasons, the sensitivity characteristics of the photoconductor can be further improved.

It is preferable that Y in the general formula (1) represents a divalent group represented by the general formula (Y1), and R ¹ in the general formula (Y1) represents a cyano group. When R ¹ represents a cyano group which is an electron accepting group, the electron acceptability of the compound (1) can be improved, and the sensitivity of the photoconductor can be further improved.

It is preferable that Y in the general formula (1) represents a divalent group represented by the general formula (Y1), and R ¹ in the general formula (Y1) represents a fluorine atom. When R ¹ is an electron-accepting group and represents a fluorine atom having a high electronegativity, the electron acceptability of the compound (1) can be improved, and the sensitivity of the photoconductor can be further improved.

The general formula (1) is a chemical formula (1-1), (1-2), (1-3), (1-4), (1-5), (1-6), or (1-7). Is preferable. That is, suitable examples of compound (1) include chemical formulas (1-1), (1-2), (1-3), (1-4), (1-5), (1-6), and so on. And the compound represented by (1-7) (hereinafter, each of which is compound (1-1), (1-2), (1-3), (1-4), (1-5), (1). -6) and (1-7) may be described).

Compound (1) is produced, for example, according to a reaction represented by the following reaction formula (R-1) (hereinafter, may be referred to as reaction (R-1)). X ^{1, X 2, and Y in the general formula (a) are synonymous with X 1 , X 2 , and} Y in the general formula (1), respectively.

In the reaction (R-1), 1 molar equivalent of the compound represented by the general formula (a) (hereinafter referred to as compound (a)) and 2 molar equivalents of bis (trimethylsilyl) carbodiimide (chemical formula (M)). The compound (represented) is reacted to obtain 1 mol equivalent of the compound (1). Specifically, in the presence of Lewis acid and a solvent, 1 molar equivalent of compound (a) and 2 molar equivalents of bis (trimethylsilyl) carbodiimide are stirred. Examples of Lewis acids include titanium tetrachloride and aluminum chloride. Examples of solvents include chloroform, methylene chloride, and ethyl acetate. The reaction (R-1) may be carried out in an atmosphere of an inert gas. Examples of the inert gas include nitrogen gas and argon gas. The reaction temperature of the reaction (R-1) is preferably −30 ° C. or higher and 0 ° C. or lower. The reaction time of the reaction (R-1) is preferably 2 hours or more and 10 hours or less.

<Second Embodiment: Photoreceptor>
Next, the photoconductor according to the second embodiment of the present invention will be described. Hereinafter, the structure of the photoconductor according to the second embodiment will be described with reference to FIGS. 1, 2, and 3. 1, FIG. 2, and FIG. 3 are partial cross-sectional views showing the structure of the photoconductor 1 according to the second embodiment, respectively. As shown in FIG. 1, the photoconductor 1 includes a conductive substrate 2 and a photosensitive layer 3. The photosensitive layer 3 is a single layer. As shown in FIG. 1, the photosensitive layer 3 may be provided directly on the conductive substrate 2. Further, as shown in FIG. 2, the photosensitive member 1 may include, for example, a conductive substrate 2, an intermediate layer 4 (for example, an undercoat layer), and a photosensitive layer 3. In the example shown in FIG. 2, the photosensitive layer 3 is provided on the conductive substrate 2 via the intermediate layer 4. As shown in FIG. 1, the photosensitive layer 3 may be the outermost surface layer of the photosensitive member 1. Further, as shown in FIG. 3, the photoconductor 1 may be provided with a protective layer 5 as the outermost surface layer. The thickness of the photosensitive layer 3 is not particularly limited. The thickness of the photosensitive layer 3 is preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 50 μm or less. The structure of the photoconductor has been described above with reference to FIGS. 1, 2, and 3. Hereinafter, the photoconductor according to the second embodiment will be described in more detail.

[Photosensitive layer]
The photosensitive layer contains at least a charge generator and the compound (1) according to the first embodiment. The compound (1) is contained in the photosensitive layer, for example, as an electron transporting agent. The photosensitive layer may further contain a hole transporting agent. The photosensitive layer may further contain a binder resin. The photosensitive layer may further contain an additive, if necessary.

(Charge generator)
Examples of the charge generator include phthalocyanine pigments, perylene pigments, bisazo pigments, trisazo pigments, dithioketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaline pigments, indigo pigments, azurenium pigments, and cyanine. Pigments, powders of inorganic photoconductive materials (eg, selenium, selenium-tellu, selenium-arsenide, cadmium sulfide, and amorphous silicon), pyrylium pigments, anthanthrone pigments, triphenylmethane pigments, sulene pigments, toluidin pigments. , Pyrazoline pigments, and quinacridone pigments. The photosensitive layer may contain only one type of charge generator, or may contain two or more types.

Examples of the phthalocyanine pigment include non-metallic phthalocyanine and metallic phthalocyanine. Examples of the metallic phthalocyanine include titanyl phthalocyanine, hydroxygallium phthalocyanine, and chlorogallium phthalocyanine. Metal-free phthalocyanine is represented by the chemical formula (CGM-1). Titanyl phthalocyanine is represented by the chemical formula (CGM-2).

The phthalocyanine pigment may be crystalline or amorphous. Examples of the crystal of the non-metal phthalocyanine include an X-type crystal of the non-metal phthalocyanine (hereinafter, may be referred to as an X-type non-metal phthalocyanine). Examples of the crystals of titanyl phthalocyanine include α-type, β-type, and Y-type crystals of titanyl phthalocyanine (hereinafter, each may be referred to as α-type, β-type, and Y-type titanyl phthalocyanine).

For example, for a digital optical image forming apparatus (for example, a laser beam printer or a facsimile using a light source such as a semiconductor laser), it is preferable to use a photoconductor having sensitivity in a wavelength region of 700 nm or more. Since it has a high quantum yield in the wavelength region of 700 nm or more, the phthalocyanine pigment is preferable, the metal-free phthalocyanine or titanyl phthalocyanine is more preferable, and the X-type metal-free phthalocyanine or the Y-type titanyl phthalocyanine is more preferable. , Y-type titanyl phthalocyanine is particularly preferable.

The Y-type titanyl phthalocyanine has a main peak at 27.2 ° of the Bragg angle (2θ ± 0.2 °) in the CuKα characteristic X-ray diffraction spectrum, for example. The main peak in the CuKα characteristic X-ray diffraction spectrum is the peak having the first or second highest intensity in the range where the Bragg angle (2θ ± 0.2 °) is 3 ° or more and 40 ° or less. Y-type titanyl phthalocyanine does not have a peak at 26.2 ° in the CuKα characteristic X-ray diffraction spectrum.

The CuKα characteristic X-ray diffraction spectrum can be measured by, for example, the following method. First, a sample (titanylphthalocyanine) is filled in a sample holder of an X-ray diffractometer (for example, "RINT (registered trademark) 1100" manufactured by Rigaku Co., Ltd.), and an X-ray tube Cu, tube voltage 40 kV, tube current 30 mA, The X-ray diffraction spectrum is measured under the condition that the wavelength of the CuKα characteristic X-ray is 1.542 Å. The measurement range (2θ) is, for example, 3 ° or more and 40 ° or less (start angle 3 °, stop angle 40 °), and the scanning speed is, for example, 10 ° / min. The main peak is determined from the obtained X-ray diffraction spectrum, and the Bragg angle of the main peak is read.

The content of the charge generator is preferably 0.1 part by mass or more and 50 parts by mass or less, and more preferably 0.5 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the binder resin.

(Electronic transport agent)
Examples of the electron transporting agent include the compound (1) according to the first embodiment. The photosensitive layer may contain only one kind of compound (1), or may contain two or more kinds of compounds (1). Further, the photosensitive layer may contain only the compound (1) as an electron transporting agent, and further contains an electron transporting agent other than the compound (1) (hereinafter, may be referred to as another electron transporting agent). You may. Examples of other electron transporting agents include quinone compounds, diimide compounds, hydrazone compounds, thiopyran compounds, trinitrothioxanthone compounds, 3,4,5,7-tetranitro-9-fluorenone compounds, and dinitroanthracene compounds. Examples thereof include compounds, dinitroacridin-based compounds, tetracyanoethylene, 2,4,8-trinitrothioxanthone, dinitrobenzene, dinitroacridin, succinic anhydride, maleic anhydride, and dibromomaleic anhydride. Examples of the quinone compound include a diphenoquinone compound, an azoquinone compound, an anthraquinone compound, a naphthoquinone compound, a nitroanthraquinone compound, and a dinitroanthraquinone compound.

The content of the compound (1) is preferably 5 parts by mass or more and 100 parts by mass or less, and more preferably 20 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the binder resin. When the content of the compound (1) is 5 parts by mass or more with respect to 100 parts by mass of the binder resin, the sensitivity characteristics of the photoconductor can be easily improved. When the content of the compound (1) is 100 parts by mass or less with respect to 100 parts by mass of the binder resin, the compound (1) is easily dissolved in the solvent for forming the photosensitive layer, and a uniform photosensitive layer is easily formed.

(Hole transport agent)
Examples of the hole transporting agent include triphenylamine derivatives, diamine derivatives (for example, N, N, N', N'-tetraphenylbenzidine derivatives, N, N, N', N'-tetraphenylphenylenediamine derivatives, and the like. N, N, N', N'-tetraphenylnaphthylene diamine derivative, N, N, N', N'-tetraphenylphenanthrylene diamine derivative, and di (aminophenylethenyl) benzene derivative), oxadiazole System compounds (eg, 2,5-di (4-methylaminophenyl) -1,3,4-oxadiazole), styryl compounds (eg, 9- (4-diethylaminostyryl) anthracene), carbazole compounds (eg, 9- (4-diethylaminostyryl) anthracene). For example, polyvinylcarbazole), organic polysilane compounds, pyrazoline compounds (eg, 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline), hydrazone compounds, indol compounds, oxazole compounds, isooxazole compounds, thiazole. Examples thereof include a system compound, a thiadiazol system compound, an imidazole system compound, a pyrazole system compound, and a triazole system compound. The photosensitive layer may contain only one kind of hole transporting agent, or may contain two or more kinds of hole transporting agents.

The photosensitive layer preferably contains a compound represented by the general formula (10) (hereinafter, may be referred to as compound (10)). The photosensitive layer preferably contains compound (10) as, for example, a hole transporting agent.

In the general formula (10), R ¹⁰¹ , R ¹⁰² , R ¹⁰³ , R ¹⁰⁴ , R ¹⁰⁵ , and R ¹⁰⁶ are each independently an alkyl group having 1 or more and 6 or less carbon atoms and 1 or more and 6 or less carbon atoms. Represents an alkoxy group or an aryl group having 6 to 14 carbon atoms. a, b, c, and d each independently represent an integer of 0 or more and 5 or less. e and f each independently represent an integer of 0 or more and 4 or less.

When a represents an integer of 2 or more and 5 or less, the plurality of R ^101s may be the same as or different from each other. When b represents an integer of 2 or more and 5 or less, the plurality of R ¹⁰² may be the same as or different from each other. When c represents an integer of 2 or more and 5 or less, the plurality of R ^103s may be the same as or different from each other. When d represents an integer of 2 or more and 5 or less, the plurality of R ^104s may be the same as or different from each other. When e represents an integer of 2 or more and 4 or less, the plurality of R ^105s may be the same as or different from each other. When f represents an integer of 2 or more and 4 or less, the plurality of R ^106s may be the same or different from each other.

In the general formula (10), it is preferable that R ¹⁰¹ , R ¹⁰² , R ¹⁰³ , R ¹⁰⁴ , R ¹⁰⁵ , and R ¹⁰⁶ each independently represent an alkyl group having 1 or more and 6 or less carbon atoms, and the number of carbon atoms is preferably 6. It is more preferable to represent an alkyl group of 1 or more and 3 or less, and further preferably to represent a methyl group. It is preferable that a, b, c and d each independently represent 0 or 1, and more preferably 1. e and f each independently represent 0 or 1, and more preferably 1.

Preferable examples of the compound (10) include a compound represented by the following chemical formula (10-1) (hereinafter, may be referred to as a compound (10-1)).

The photosensitive layer may contain only compound (10) as a hole transporting agent. Further, the photosensitive layer may further contain a hole transporting agent other than the compound (10) in addition to the compound (10) as the hole transporting agent.

The content of the hole transporting agent is preferably 10 parts by mass or more and 200 parts by mass or less, and more preferably 10 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the binder resin.

(Binder resin)
Examples of the binder resin include thermoplastic resins, thermosetting resins, and photocurable resins. Examples of the thermoplastic resin include polycarbonate resins, polyarylate resins, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers, acrylic acid polymers, and styrene-acrylic acid copolymers. Polyethylene resin, ethylene-vinyl acetate copolymer, chlorinated polyethylene resin, polyvinyl chloride resin, polypropylene resin, ionomer resin, vinyl chloride-vinyl acetate copolymer, alkyd resin, polyamide resin, urethane resin, polysulfone resin, diallyl phthalate Examples thereof include resins, ketone resins, polyvinyl butyral resins, polyester resins, and polyether resins. Examples of the thermosetting resin include silicone resin, epoxy resin, phenol resin, urea resin, and melamine resin. Examples of the photocurable resin include an acrylic acid adduct of an epoxy compound and an acrylic acid adduct of a urethane compound. The photosensitive layer may contain only one kind of binder resin, or may contain two or more kinds of binder resins.

Among these resins, a polycarbonate resin is preferable as the binder resin because a photosensitive layer having an excellent balance of processability, mechanical properties, optical properties, and abrasion resistance can be obtained. Examples of the polycarbonate resin include bisphenol ZC type polycarbonate resin, bisphenol C type polycarbonate resin, bisphenol A type polycarbonate resin, and bisphenol Z type polycarbonate resin. The bisphenol Z-type polycarbonate resin has a repeating unit represented by the following chemical formula (20). Hereinafter, the polycarbonate resin having a repeating unit represented by the chemical formula (20) may be referred to as a polycarbonate resin (20). The polycarbonate resin (20) preferably has only the repeating unit (20) as the repeating unit.

(Additive)
Additives include, for example, anti-deterioration agents (eg, antioxidants, radical scavengers, single-term quenchers, and UV absorbers), softeners, surfactants, bulking agents, thickeners, dispersion stability. Agents, waxes, acceptors, donors, surfactants, plasticizers, sensitizers, and leveling agents.

(Combination of materials)
The material contained in the photosensitive layer is preferably each of the combinations shown below. In one example of the combination, the electron transport agent is compound (1-1), (1-2), (1-3), (1-4), (1-5), (1-6), or (1-1). 7) is included, and the hole transport agent comprises compound (10-1). In one example of the combination, the electron transport agent is compound (1-1), (1-2), (1-3), (1-4), (1-5), (1-6), or (1-1). 7) is included, and the binder contains a polycarbonate resin (20). In one example of the combination, the electron transport agent is compound (1-1), (1-2), (1-3), (1-4), (1-5), (1-6), or (1-1). 7) is included, and the charge generator contains X-type metal-free phthalocyanine. In one example of the combination, the electron transport agent is compound (1-1), (1-2), (1-3), (1-4), (1-5), (1-6), or (1-1). 7) is included, and the charge generator contains Y-type titanylphthalocyanine. In one example of the combination, the electron transport agent is compound (1-1), (1-2), (1-3), (1-4), (1-5), (1-6), or (1-1). 7) is included, the hole transport agent comprises compound (10-1), and the binder comprises a polycarbonate resin (20). In one example of the combination, the electron transport agent is compound (1-1), (1-2), (1-3), (1-4), (1-5), (1-6), or (1-1). 7), the hole transport agent contains compound (10-1), the binder contains polycarbonate resin (20), and the charge generator contains X-type metalless phthalocyanine. In one example of the combination, the electron transport agent is compound (1-1), (1-2), (1-3), (1-4), (1-5), (1-6), or (1-1). 7), the hole transport agent contains the compound (10-1), the binder contains the polycarbonate resin (20), and the charge generator contains the Y-type titanyl phthalocyanine.

[Conductive substrate]
The conductive substrate may be formed of a material having at least a conductive surface. An example of a conductive substrate is a conductive substrate made of a conductive material. Another example of a conductive substrate is a conductive substrate coated with a conductive material. Examples of the conductive material include aluminum, iron, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, and brass. One of these conductive materials may be used alone, or two or more of them may be used in combination (for example, as an alloy). Among these conductive materials, aluminum or an aluminum alloy is preferable because the transfer of electric charges from the photosensitive layer to the conductive substrate is good.

The shape of the conductive substrate is appropriately selected according to the structure of the image forming apparatus. Examples of the shape of the conductive substrate include a sheet shape and a drum shape. Further, the thickness of the conductive substrate is appropriately selected according to the shape of the conductive substrate.

[Middle layer]
The intermediate layer (undercoat layer) contains, for example, inorganic particles and a resin (resin for the intermediate layer) used for the intermediate layer. The presence of the intermediate layer smoothes the flow of current generated when the photoconductor is exposed while maintaining an insulating state to the extent that leakage can be suppressed, and suppresses an increase in resistance.

Inorganic particles include, for example, metal (eg, aluminum, iron, or copper) particles, metal oxide (eg, titanium oxide, alumina, zirconium oxide, tin oxide, or zinc oxide) particles, and non-metal oxides. Particles of (eg silica) can be mentioned. These inorganic particles may be used alone or in combination of two or more.

The example of the resin for the intermediate layer is the same as the example of the binder resin contained in the photosensitive layer. The intermediate layer may contain additives, if necessary. The example of the additive contained in the intermediate layer is the same as the example of the additive contained in the photosensitive layer.

[Manufacturing method of photoconductor]
The photoconductor is produced, for example, by applying a coating liquid for forming a photosensitive layer (hereinafter, may be referred to as a coating liquid) onto a conductive substrate and drying the photoconductor. The coating solution dissolves or disperses a charge generator, compound (1), and components added as necessary (for example, at least one of a hole transporting agent, a binder resin, and an additive) in a solvent. Manufactured by letting.

The solvent contained in the coating liquid is not particularly limited as long as each component contained in the coating liquid can be dissolved or dispersed. Examples of solvents include alcohols (eg, methanol, ethanol, isopropanol or butanol), aliphatic hydrocarbons (eg, n-hexane, octane or cyclohexane), aromatic hydrocarbons (eg, benzene, toluene or xylene). Halogenated hydrocarbons (eg dichloromethane, dichloroethane, carbon tetrachloride or chlorobenzene), ethers (eg dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether or propylene glycol monomethyl ether), ketones (eg acetone, Methyl ethyl ketone or cyclohexanone), esters (eg, ethyl acetate or methyl acetate), dimethylformaldehyde, dimethylformamide, and dimethylsulfoxide. One of these solvents may be used alone, or two or more of them may be used in combination. In order to improve workability during the production of the photoconductor, it is preferable to use a non-halogenated solvent (solvent other than halogenated hydrocarbon).

The coating liquid is prepared by mixing each component and dispersing it in a solvent. For mixing or dispersion, for example, a bead mill, a roll mill, a ball mill, an attritor, a paint shaker, or an ultrasonic disperser can be used.

The coating liquid may contain, for example, a surfactant in order to improve the dispersibility of each component.

The method for applying the coating liquid is not particularly limited as long as the coating liquid can be uniformly applied on the conductive substrate. Examples of the coating method include a blade coating method, a dip coating method, a spray coating method, a spin coating method, and a bar coating method.

The method for drying the coating liquid is not particularly limited as long as the solvent in the coating liquid can be evaporated. For example, a method of heat treatment (hot air drying) using a high temperature dryer or a vacuum dryer can be mentioned. The heat treatment temperature is, for example, a temperature of 40 ° C. or higher and 150 ° C. or lower. The heat treatment time is, for example, 3 minutes or more and 120 minutes or less.

The method for producing the photoconductor may further include one or both of the step of forming the intermediate layer and the step of forming the protective layer, if necessary. In the step of forming the intermediate layer and the step of forming the protective layer, a known method is appropriately selected.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the scope of the examples.

<Synthesis of compounds (1-1) to (1-7)>
Each of the compounds (1-1) to (1-7) described in the first embodiment was synthesized by the following method. The yield of each compound was determined by molar ratio conversion.

(Synthesis of compound (1-1))
Compound (1-1) was synthesized according to the reaction represented by the following reaction formula (r-1) (hereinafter referred to as reaction (r-1)).

The compound (1.00 g, 2.7 mmol) represented by the chemical formula (a-1) was dissolved in chloroform (100 mL) to obtain a chloroform solution A.

Chloroform solution A was placed in the reaction vessel, and the air in the reaction vessel was replaced with nitrogen gas. Titanium tetrachloride (2.50 g, 13.3 mmol) was added dropwise to chloroform solution A at −20 ° C. Next, the compound represented by the chemical formula (M) (bis (trimethylsilyl) carbodiimide, 2.97 g, 16.0 mmol) was added to the chloroform solution A, and the mixture was stirred for 5 hours. The temperature of the contents of the reaction vessel was returned to room temperature, and the contents (liquid) were taken out. Water (100 mL) was added to the removed liquid to extract the chloroform layer. The solvent was distilled off from the chloroform layer under reduced pressure to obtain a residue. The residue was purified by silica gel column chromatography using chloroform as a developing solvent to obtain compound (1-1). The yield of compound (1-1) was 0.69 g. The yield of the compound (1-1) from the compound represented by the chemical formula (a-1) was 60%.

(Synthesis of compounds (1-2) to (1-7))
Synthesis of compound (1-1) except that the compound represented by the chemical formula (a-1) of 1.00 g was changed to the compound of the amount and type shown in the “Compound (a)” column of Table 1. Each of the compounds (1-2) to (1-7) was synthesized by the same method. The yields and yields of each of the compounds (1-2) to (1-7) are shown in Table 1. The compounds (a-2) to (a-7) shown in the "Compound (a)" column of Table 1 are represented by the following chemical formulas (a-2) to (a-7), respectively.

Next, the infrared absorption spectra of the produced compounds (1-1) to (1-7) were measured using a Fourier transform infrared spectrophotometer (“SPETRUM ONE” manufactured by PerkinElmer). Samples were prepared by the KBr (potassium bromide) tablet method. From the measured infrared absorption spectra, it was confirmed that compounds (1-1) to (1-7) were obtained, respectively. Among these, compound (1-6) is given as a representative example. The wave number (ν _MAX ) of the absorption peak of compound (1-6) is shown below.
Compound (1-6): IRcm ^-1 : 2164,1562,152,1471,1294,668.

<Manufacturing of photoconductor>
Each of the photoconductors (A-1) to (A-14) and (B-1) to (B-4) was produced. In order to produce these photoconductors, Y-type titanyl phthalocyanine and X-type metal-free phthalocyanine described in the second embodiment were prepared as charge generators. As the hole transporting agent, the compound (10-1) described in the second embodiment was prepared. As the binder resin, the polycarbonate resin (20) described in the second embodiment was prepared. The viscosity average molecular weight of the polycarbonate resin (20) was 50,000. The synthesized compounds (1-1) to (1-7) were used as the electron transporting agent. Further, as the electron transporting agent used in the comparative example, the compounds represented by the following chemical formulas (E-1) and (E-2) (hereinafter, they are referred to as compounds (E-1) and (E-2), respectively. ) Was prepared.

(Manufacturing of Photoconductor (A-1))
2 parts by mass of X-type metal-free phthalanine which is a charge generator, 50 parts by mass of compound (10-1) which is a hole transport agent, 30 parts by mass of compound (1-1) which is an electron transport agent, and polycarbonate which is a binder resin. 100 parts by mass of the resin (20) and 600 parts by mass of tetrahydrofuran as a solvent were mixed for 12 hours using a ball mill to obtain a coating liquid. The coating liquid was applied onto a conductive substrate (aluminum drum-shaped support, diameter 30 mm, total length 238.5 mm) using the blade coating method. The applied coating liquid was dried with hot air at 120 ° C. for 80 minutes. In this way, a single photosensitive layer (thickness 30 μm) was formed on the conductive substrate to obtain a photosensitive member (A-1).

(Manufacturing of Photoreceptors (A-2) to (A-14) and (B-1) to (B-4))
Photoconductors (A-2) to (A-14) and (B-) were produced by the same method as for producing the photoconductor (A-1), except that the charge generator and the electron transporting agent shown in Table 2 were used. Each of 1) to (B-4) was manufactured.

<Evaluation of sensitivity characteristics>
Sensitivity characteristics were evaluated for each of the photoconductors (A-1) to (A-14) and (B-1) to (B-4). The sensitivity characteristics were evaluated in an environment with a temperature of 23 ° C. and a relative humidity of 50% RH. First, the surface of the photoconductor was charged to + 600 V using a drum sensitivity tester (manufactured by Gentec Co., Ltd.). Then, using a bandpass filter, monochromatic light (wavelength 780 nm, half width 20 nm, light energy 1.5 μJ / cm ² ) was extracted from the white light of the halogen lamp. The surface of the photoconductor was irradiated with the extracted monochromatic light. The surface potential of the photoconductor was measured 50 milliseconds after the end of irradiation. The measured surface potential was defined as the post-exposure potential ( _VL , unit: + V). The post-exposure potential ( _VL ) of the photoconductor is shown in Table 2. The smaller the positive value of the post-exposure potential ( _VL ), the better the sensitivity characteristics (more specifically, the light sensitivity characteristics) of the photoconductor.

The meanings of the terms in Table 2 are as follows. "CGM" indicates a charge generator. "ETM" refers to an electron transport agent. " _VL " indicates the potential after exposure. "XH ₂ Pc" indicates X-type metal-free phthalocyanine. "Y-TiOPc" indicates Y-type titanylphthalocyanine.

As is clear from Table 2, the photosensitive layers of the photoconductors (A-1) to (A-14) are the charge generator and the compound (1) (more specifically, the compounds (1-1) to (1) to ( It contained at least one of 1-7)). As is clear from Table 2, the post-exposure potentials of the photoconductors (A-1) to (A-14) were +141 V or less. On the other hand, the photosensitive layers of the photoconductors (B-1) to (B-4) contained the compound (E-1) or (E-2), but the compounds (E-1) and (E-2) were contained. ) Was not a compound included in the general formula (1). The post-exposure potentials of the photoconductors (B-1) to (B-4) were +158 V or higher. The photoconductors (A-1) to (A-14) were superior in sensitivity characteristics to the photoconductors (B-1) to (B-4).

From the above, it was shown that the compound (1) of the present invention can improve the sensitivity characteristics of the photoconductor when it is contained in the photosensitive layer. Moreover, it was shown that the photoconductor of the present invention is excellent in sensitivity characteristics.

The compound according to the present invention can be used for a photoconductor. The photoconductor according to the present invention can be used in an image forming apparatus.

1 Photoreceptor (electrophotograph photoconductor)
2 Conductive substrate 3 Photosensitive layer 4 Intermediate layer 5 Protective layer

Claims (10)

A compound represented by the general formula (1).

(In the general formula (1), X ¹ and X ² each independently represent an oxygen atom or a sulfur atom, and Y represents a divalent group represented by the general formula (Y1) or (Y2). .)

(R ¹ in the general formula (Y1) and R ² in the general formula (Y2) have 6 or more carbon atoms which may be independently substituted with an alkyl group having 1 or more and 10 or less carbon atoms. 22 or less aryl groups, 1 or more and 8 or less carbon atoms, alkyl groups, 7 or more and 20 or less carbon atoms, cycloalkyl groups with 3 or more and 20 or less carbon atoms, and alkoxy groups with 1 or more and 6 or less carbon atoms. , Halogen atom, cyano group, or -CO-OR ³ group, R ³ represents an alkyl group having 1 or more carbon atoms and 8 or less carbon atoms.
M in the general formula (Y1) represents an integer of 0 or more and 4 or less.
N in the general formula (Y2) represents an integer of 0 or more and 6 or less.
* In the general formulas (Y1) and (Y2) represents a bond. ) R ¹ in the general formula (Y1) and R ² in the general formula (Y2) independently have an alkyl group having 1 or more and 8 or less carbon atoms, a halogen atom, a cyano group, or -CO-OR. The compound according to claim ^{1, wherein R 3 represents} an alkyl group having 1 or more and 8 or less carbon atoms. Y in the general formula (1) represents a divalent group represented by the general formula (Y1).
The compound according to claim 1 or 2, wherein R ¹ in the general formula (Y1) represents an alkyl group having 4 or more and 8 or less carbon atoms. Y in the general formula (1) represents a divalent group represented by the general formula (Y1).
The compound according to claim 1 or 2, wherein R ¹ in the general formula (Y1) represents a cyano group. Y in the general formula (1) represents a divalent group represented by the general formula (Y1).
The compound according to claim 1 or 2, wherein R ¹ in the general formula (Y1) represents a fluorine atom. The general formula (1) is the chemical formula (1-1), (1-2), (1-3), (1-4), (1-5), (1-6), or (1-7). ), The compound according to claim 1 or 2.

With a conductive substrate and a photosensitive layer,
The photosensitive layer is a single layer.
The photosensitive layer is an electrophotographic photosensitive member containing a charge generator and the compound according to any one of claims 1 to 6. The electrophotographic photosensitive member according to claim 7, wherein the photosensitive layer further contains a compound represented by the general formula (10).

(In the above general formula (10), R ¹⁰¹ , R ¹⁰² , R ¹⁰³ , R ¹⁰⁴ , R ¹⁰⁵ , and R ¹⁰⁶ are each independently an alkyl group having 1 or more and 6 or less carbon atoms and 1 or more and 6 carbon atoms. Represents the following alkoxy group or aryl group having 6 or more carbon atoms and 14 or less carbon atoms.
a, b, c, and d each independently represent an integer of 0 or more and 5 or less.
e and f each independently represent an integer of 0 or more and 4 or less. ) The electrophotographic photosensitive member according to claim 8, wherein the compound represented by the general formula (10) is a compound represented by the chemical formula (10-1).

The electrophotographic photosensitive member according to any one of claims 7 to 9, wherein the photosensitive layer further contains a polycarbonate resin having a repeating unit represented by the chemical formula (20).

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