JP2014029502A - Electrophotographic photoreceptor, process cartridge, and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor in which generation of positive memory is suppressed, and potential variation during long-term repeated use is suppressed, and to provide an electrophotographic device and a process cartridge, having the electrophotographic photoreceptor.SOLUTION: An electron transport layer is a hardened film containing a carbon atom, a nitrogen atom, and an oxygen atom; and when a ratio of the carbon atoms, a ratio of the nitrogen atoms, and a ratio of the oxygen atoms are analyzed by using an X-ray photoelectron spectroscopy (ESCA) at 10 points, standard deviations σ(C), σ(N), and σ(O) of the ratio of the carbon atoms, the ratio of the nitrogen atoms, and the ratio of the oxygen atoms, respectively satisfy following formulas (1) to (3). σ(C)≤1.5 (1), σ(N)≤1.5 (2), and σ(O)≤1.5 (3)

Description

  The present invention relates to an electrophotographic photosensitive member, a process cartridge having an electrophotographic photosensitive member, and an electrophotographic apparatus.

  At present, as an electrophotographic photosensitive member used in a process cartridge or an electrophotographic apparatus, an electrophotographic photosensitive member containing an organic photoconductive substance is widely used in the market. An electrophotographic photoreceptor generally has a support and a photosensitive layer formed on the support. An undercoat layer is provided between the support and the photosensitive layer for the purpose of suppressing charge injection from the support side to the photosensitive layer (charge generation layer) side and suppressing the occurrence of image defects such as fog. It has been.

  On the other hand, by providing the undercoat layer, a potential change during repeated use is likely to occur due to a resistance change in the undercoat layer. Thus, as a technique for suppressing potential fluctuation, a technique is disclosed in which an electron transport substance is contained in the undercoat layer, and the undercoat layer is a layer having an electron transport ability (hereinafter also referred to as an electron transport layer). At the same time, in order to prevent the electron transport material from eluting during formation of the photosensitive layer formed on the undercoat layer, when the undercoat layer contains an electron transport material, the undercoat layer is a photosensitive layer coating solution. A technique using a curable material that is hardly soluble in these solvents has been proposed.

  Patent Document 1 discloses an electron transport layer containing a polymer of a condensation polymer (electron transport material) having an aromatic tetracarbonylbisimide skeleton and a crosslinking site and a crosslinking agent. Patent Document 2 discloses that the undercoat layer contains a polymer of an electron transporting substance having a non-hydrolyzable polymerizable functional group.

Special table 2009-505156 JP 2003-330209 A

  However, as a result of the study by the present inventors, when a positive charge is applied to the electrophotographic photosensitive member by using the undercoat layer as an electron transport layer, a positive charge is generated due to the positive charge remaining in the electron transport layer. It was found that memory images may occur. A positive memory image means that a positive charge is applied to the electrophotographic photosensitive member during transfer or rubbing of the electrophotographic photosensitive member by a cleaning means in an electrophotographic apparatus, and a potential difference from an unapplied portion is generated. This is an image in which the phenomenon that the density of the image becomes deeper occurs.

  In the techniques disclosed in Patent Documents 1 and 2, since a curable material is used for the electron transport layer, the uniformity of the charge transport structure in the electron transport layer is lowered, and a plus memory image is likely to be generated. There was room for improvement.

  An object of the present invention is to provide an electrophotographic photosensitive member in which the occurrence of plus memory is suppressed and the potential fluctuation during repeated long-term use is suppressed, and a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member. There is.

The present invention is an electrophotographic photosensitive member having a support, an electron transport layer formed on the support, and a photosensitive layer formed on the electron transport layer,
The electron transport layer is a cured film containing carbon atoms, nitrogen atoms and oxygen atoms,
The electrophotographic photosensitive member is characterized in that the electron transport layer satisfies the following formulas (1) to (3).
σ (C) ≦ 1.5 (1)
σ (N) ≦ 1.5 (2)
σ (O) ≦ 1.5 (3)
(In the formulas (1) to (3),
σ (C) is 10 points obtained when the ratio (atoms%) of the carbon atoms to all atoms excluding hydrogen atoms in the electron transport layer at 10 points was analyzed by X-ray photoelectron spectroscopy (ESCA). Indicates the standard deviation of the values.
σ (N) is 10 points obtained when the ratio (atoms%) of the nitrogen atoms to all atoms excluding hydrogen atoms in the electron transport layer at 10 points was analyzed by X-ray photoelectron spectroscopy (ESCA). Indicates the standard deviation of the values.
σ (O) is 10 points obtained when the ratio (atoms%) of the oxygen atoms to all atoms excluding hydrogen atoms in the electron transport layer at 10 points is analyzed by X-ray photoelectron spectroscopy (ESCA). Indicates the standard deviation of the values.
The ten points consist of the upper and lower points of the electron transport layer and eight points that divide the thickness of the electron transport layer into nine equal parts in the depth direction. )

  Further, the present invention integrally supports the electrophotographic photosensitive member and at least one means selected from the group consisting of a charging means, a developing means, a transfer means, and a cleaning means, and is detachable from the main body of the electrophotographic apparatus. The present invention relates to a process cartridge.

  The present invention also relates to the electrophotographic photosensitive member, and an electrophotographic apparatus having a charging unit, an exposure unit, a developing unit, and a transfer unit.

  According to the present invention, there are provided an electrophotographic photosensitive member in which the occurrence of plus memory is suppressed and the potential fluctuation at the time of repeated use for a long period is suppressed, and a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member. be able to.

It is a figure which shows an example of the layer structure of an electrophotographic photoreceptor. It is a figure which shows the positional relationship of these 10 points | pieces when measuring the ratio of the carbon atom of the electron carrying layer, the ratio of a nitrogen atom, and the ratio of an oxygen atom by X-ray photoelectron spectroscopy (ESCA). 1 is a diagram illustrating a schematic configuration of an electrophotographic apparatus having a process cartridge including an electrophotographic photosensitive member. It is a figure explaining a 1 dot Keima pattern image.

  First, a measurement method for evaluating whether or not the electrophotographic photosensitive member satisfies the above formula (1) of the present invention (hereinafter referred to as “the evaluation method of the present invention”), and the electrophotographic photosensitive member used in the evaluation method of the present invention. The body (hereinafter also referred to as “determination electrophotographic photoreceptor”) will be described.

  In the present invention, the ratio of carbon element (carbon atom), oxygen element (oxygen atom) and nitrogen element (nitrogen atom) in the electron transport layer at 10 points are analyzed by X-ray photoelectron spectroscopy (ESCA), respectively. . At that time, the standard deviations σ (C), σ (N) of the carbon atom ratio (atoms%), the nitrogen atom ratio (atoms%), and the oxygen atom ratio (atoms%) at the 10 points, respectively, σ (O) is calculated. The ten points consist of the upper and lower points of the electron transport layer and eight points that divide the thickness of the electron transport layer into nine equal parts in the depth direction.

  In order to divide the film thickness of the electron transport layer into 9 depths from the photosensitive layer side, the following method can be mentioned. A method of peeling the photosensitive layer and analyzing the ratio of each atom of the electron transport layer in the depth direction using ESCA, and each atom of the electron transport layer in the depth direction using ESCA while the photosensitive layer is laminated. There is a method of analyzing the ratio. The analysis after peeling off the photosensitive layer is simple because the time for etching in the depth direction using ESCA can be greatly shortened. When analyzing the ratio of each atom by etching in the depth direction using ESCA from above the photosensitive layer, the specific atoms contained in the photosensitive layer (for example, metal atoms contained in the charge generation material) are measured. When it disappears, it is determined as the surface of the electron transport layer. The interface between the support or the conductive layer described later and the electron transport layer is determined as follows. That is, the electrons up to the measurement point immediately before the measurement of the specific atoms contained in the support or the conductive layer (for example, Al if the support is made of aluminum, or the metal atom of the conductive particles if the support is made of a conductive layer). Judge as the transport layer.

  The photosensitive layer may be a single-layer type photosensitive layer or a stacked type (functional separation type) photosensitive layer separated into a charge generation layer containing a charge generation material and a hole transport layer containing a hole transport material.

  Examples of the method for peeling the photosensitive layer include a method for dissolving the photosensitive layer and immersing the electrophotographic photosensitive member in a solvent that is hardly soluble in the electron transport layer to peel the photosensitive layer, and a method for polishing the photosensitive layer. . In addition, in the case of a laminated photosensitive layer having a charge generation layer and a hole transport layer, it is preferable to peel off with an optimum solvent for each of the charge generation layer and the hole transport layer. It is preferable to use a solvent used in the layer coating solution. The kind of the solvent is mentioned later. The electrophotographic photosensitive member for determination can be obtained by immersing the electrophotographic photosensitive member in this solvent to dissolve the photosensitive layer and then drying it. The fact that the photosensitive layer has been peeled can be confirmed by, for example, the fact that the resin component of the photosensitive layer is not observed by the ATR method (total reflection method) in the FTIR measurement method.

  As a method for polishing the photosensitive layer, for example, a drum tape polishing apparatus manufactured by Canon Inc. is used with a wrapping tape (C2000: manufactured by Fuji Photo Film Co., Ltd.). At that time, it is preferable that the film thickness is sequentially measured so that the photosensitive layer is excessively polished and does not polish to the electron transport layer, and is measured at the place where the photosensitive layer is completely removed while observing the surface of the electrophotographic photosensitive member.

Next, a method for analyzing the ratio of each atom in the depth direction using X-ray photoelectron spectroscopy (ESCA) will be described. Below, an example of the apparatus and conditions to be used is shown.
Device used: Quantum 2000 Scanning ESCA Microprobe manufactured by PHI (Physical Electronics Industries, Inc.)
Top surface and internal measurement conditions after etching:
X-ray source Al Ka1486.6eV (25W15kV), measurement area 100μm
Spectral region 1500 × 300 μm, Angle 45 °,
Pass Energy 117.40eV
Etching conditions:
Ion gun C60 (10 kV 2 mm × 2 mm), Angle 70 °.

  The etching time was 30 min (0.5 μm / 30 min) to obtain a depth of 0.5 μm of the electron transport layer. In addition, the depth was identified by cross-sectional FIB-SEM (Hitachi High-Tech FB-2000C) cross-sectional observation after the etching of the electron carrying layer. The present invention analyzes the ratio of each atom at a total of 10 points consisting of 8 points that divide the thickness of the electron transport layer into 9 parts in the depth direction, and the upper and lower points of the electron transport layer. As shown in FIG. 2, the ratio of each atom is analyzed for a total of 10 black spots indicated by arrows. As for the etching time, there is a method in which the film thickness of the electron transport layer to be measured is measured in advance by observing the FIB-SEM cross section, and the film thickness of the electron transport layer is measured and the etching time is determined accordingly. In addition, it is obtained by analyzing the ratio of each atom every 30 seconds and determining the electron transport layer up to the measurement point immediately before the specific atom contained in the support or conductive layer is measured. All the measurement points may be divided into 9 equal parts and 10 points may be selected. If this etching time is performed every 30 seconds, in the electron transport layer having a film thickness of about 0.1 μm or more, it is possible to analyze the ratio of 10 atoms in the depth direction evenly.

From the peak intensities of carbon atoms, nitrogen atoms, and oxygen atoms measured under the above conditions, the surface atomic concentration (atomic%) is calculated using a relative sensitivity factor provided by PHI. The measurement peak top ranges of carbon atoms, nitrogen atoms, and oxygen atoms are as follows.
C1s: 278 to 298 eV
O1s: 525-545eV
N1s: 390 to 410 eV.

The electron transport layer contains carbon atoms, nitrogen atoms, and oxygen atoms, but may contain other atoms. For the purpose of enhancing electron withdrawing properties, the structure of the electron transport layer (electron transport material) may have halogen atoms such as fluorine, chlorine and bromine, atoms such as silicon atoms, phosphorus atoms and sulfur atoms. The content of these atoms in the transport material structure is very low. Therefore, even if the ratio of each atom is analyzed by ESCA, the ratio is very small and is not appropriate for obtaining the standard deviation. Note that hydrogen atoms have no measurement sensitivity in ESCA. Therefore, carbon atoms, oxygen atoms, and nitrogen atoms are selected as the atoms constituting the electron transport layer, and the standard deviation derived from the values of 10 points of the carbon atom ratio, oxygen atom ratio, and nitrogen atom ratio, respectively. (Σ (C), σ (N), σ (O)) is calculated. If the standard deviations (σ (C), σ (N), σ (O)) all satisfy the following formulas (1) to (3), carbon atoms, nitrogen atoms, and oxygen atoms in the electron transport layer are uniform. It means that the electron transport layer is highly uniform.
σ (C) ≦ 1.5 (1)
σ (N) ≦ 1.5 (2)
σ (O) ≦ 1.5 (3)
(In the formulas (1) to (3), σ (C) is the ratio (atoms%) of the carbon atoms to all atoms excluding hydrogen atoms in the electron transport layer at 10 points. X-ray photoelectron spectroscopy (ESCA) Indicates the standard deviation of the obtained 10 points when analyzed by the following equation: σ (N) is the ratio of the nitrogen atoms to all atoms excluding hydrogen atoms in the electron transport layer at 10 points (atoms%). The standard deviation of the obtained 10 points when analyzed by X-ray photoelectron spectroscopy (ESCA) is shown, where σ (O) is the oxygen relative to all atoms except the hydrogen atoms of the electron transport layer at 10 points. When the atomic ratio (atoms%) is analyzed by X-ray photoelectron spectroscopy (ESCA), the standard deviation of the obtained 10-point value is shown.

  The present inventors have found that the standard deviations (σ (C), σ (N), σ (O)) of the carbon atom ratio, nitrogen atom ratio, and oxygen atom ratio are the formulas (1) to (3). The reason why the occurrence of plus memory is suppressed by satisfying the above is estimated as follows.

  If the electron transport layer is not a cured film but a film in which the electron transport layer is dissolved by the solvent of the photosensitive layer, when the photosensitive layer is formed, the electron transport material is easily eluted into the upper photosensitive layer, Injection of electrons from the layer side to the electron transport layer side is likely to be suppressed. As a result, the sensitivity is lowered and a large amount of charges stay in the photosensitive layer, so that memory tends to occur. Therefore, it is appropriate that the electron transport layer is a cured film.

  However, when the electron transport layer is a cured film, substances having the same structure used when forming the electron transport layer are aggregated and component unevenness in the electron transport layer is likely to occur. As a result, when a positive charge is applied, the charge tends to stay in the electron transport layer, and a positive memory image is likely to be generated.

  In addition, the electron transport layer, which is a cured film, has a feature that moves only electrons generated in the photosensitive layer to the support side and suppresses the injection of positive charges from the support side to the photosensitive layer side. However, if a positive charge is injected from the photosensitive layer side due to the application of a positive charge, electrons are less likely to move to the support side compared to an undercoat layer that does not have an electron transport capability, and a positive memory image is generated. It will be easier.

  Then, it is thought that satisfy | filling said Formula (1)-(3) has shown that each of the carbon atom of a electron carrying layer, a nitrogen atom, and an oxygen atom exists uniformly. The carbon atom, nitrogen atom, and oxygen atom are the main constituent atoms among all the constituent atoms of the electron transport layer. If these three constituent atoms are present uniformly, highly uniform electron transport is possible. It is considered that a layer is formed. And since the electron transport layer is uniform, even if a positive charge is applied and a positive charge is injected from the photosensitive layer side, the decrease in the movement of electrons to the support side is suppressed, and the movement of electrons is made smooth. Yes. It is speculated that this suppresses the occurrence of positive memory.

  In the charge transport layer, the total (atoms%) of the carbon atom ratio (atoms%), the nitrogen atom ratio (atoms%), and the oxygen atom ratio (atoms%) must be 50% or more and 100% or less. Is preferred. Note that hydrogen atoms having no measurement sensitivity in ESCA are excluded. More preferably, it is 90% or more and 100% or less.

  The electrophotographic photoreceptor of the present invention includes a support, an electron transport layer formed on the support, a charge generation layer formed on the electron transport layer, and a hole transport layer formed on the charge generation layer An electrophotographic photosensitive member having Alternatively, the electrophotographic photosensitive member includes a support, an electron transport layer formed on the support, and a photosensitive layer formed on the electron transport layer. The photosensitive layer is preferably a stacked type (functional separation type) photosensitive layer separated into a charge generation layer containing a charge generation material and a hole transport layer containing a hole transport material.

  FIGS. 1A and 1B are diagrams showing an example of the layer structure of the electrophotographic photosensitive member of the present invention. In FIGS. 1A and 1B, 101 is a support, 102 is an electron transport layer, 103 is a photosensitive layer, 104 is a charge generation layer, and 105 is a hole transport layer.

  As a general electrophotographic photosensitive member, a cylindrical electrophotographic photosensitive member in which a photosensitive layer (charge generation layer, hole transport layer) is formed on a cylindrical support is widely used. It is also possible to adopt a shape such as

(Electron transport layer)
The electron transport layer of the present invention is a cured film containing carbon atoms, nitrogen atoms and oxygen atoms as constituent atoms. From the viewpoint of uniformity of the electron transport layer, a polymer obtained by polymerizing a composition containing an electron transport material having a polymerizable functional group, a thermoplastic resin having a polymerizable functional group, and a crosslinking agent is provided. It is preferable to contain.

When the standard deviations σ (C), σ (N), and σ (O) satisfy the following formulas (4) to (6), the uniformity of the electron transport structure in the electron transport layer is improved, and more positive memory is obtained. Since the effect which reduces generation | occurrence | production of this is acquired, it is preferable.
σ (C) ≦ 1.0 (4)
σ (N) ≦ 1.0 (5)
σ (O) ≦ 1.0 (6)

[Electron transport material]
Examples of the electron transport material include a quinone compound, an imide compound, a benzimidazole compound, a cyclopentadienylidene compound, and the like.
The electron transport material is preferably an electron transport material having a polymerizable functional group. Examples of the polymerizable functional group include a hydroxy group, a thiol group, an amino group, a carboxyl group, and a methoxy group.

  The molecular weight of the electron transport material having a polymerizable functional group is preferably closer to the molecular weight of the crosslinking agent because the uniformity of the electron transport layer is increased. The ratio between the molecular weight of the electron transport material and the molecular weight of the crosslinking agent is preferably in the range of 0.5 to 1.5, and more preferably in the range of 0.8 to 1.2. In addition, the molecular weight (Mw) of the electron transport material is preferably 1000 or less because it can be uniformly bonded to a thermoplastic resin having a polymerizable functional group and the effect of reducing a plus memory image can be obtained. More preferably, it is 200 or more and 840 or less.

式（Ａ１）〜（Ａ９）中、Ｒ^１０１〜Ｒ^１０６、Ｒ^２０１〜Ｒ^２１０、Ｒ^３０１〜Ｒ^３０８、Ｒ^４０１〜Ｒ^４０８、Ｒ^５０１〜Ｒ^５１０、Ｒ^６０１〜Ｒ^６０６、Ｒ^７０１〜Ｒ^７０８、Ｒ^８０１〜Ｒ^８１０、Ｒ^９０１〜Ｒ^９０８は、それぞれ独立に、下記式（Ａ）で示される１価の基、水素原子、シアノ基、ニトロ基、ハロゲン原子、アルコキシカルボニル基、置換もしくは無置換のアルキル基、置換もしくは無置換のアリール基または置換もしくは無置換の複素環を示す。該アルキル基の主鎖中の炭素原子の１つは、Ｏ、Ｓ、ＮＨ、ＮＲ^１００１（Ｒ^１００１はアルキル基）で置き換わっても良い。該置換のアルキル基の置換基は、アルキル基、アリール基、アルコキシカルボニル基、またはハロゲン原子である。該置換のアリール基または該置換の複素環基の置換基は、ハロゲン原子、ニトロ基、シアノ基、アルキル基、ハロゲン置換アルキル基である。Ｚ^２０１、Ｚ^３０１、Ｚ^４０１およびＺ^５０１は、それぞれ独立に、炭素原子、窒素原子、または酸素原子を示す。Ｚ^２０１が酸素原子である場合はＲ^２０９およびＲ^２１０は存在せず、Ｚ^２０１が窒素原子である場合はＲ^２１０は存在しない。Ｚ^３０１が酸素原子である場合はＲ^３０７およびＲ^３０８は存在せず、Ｚ^３０１が窒素原子である場合はＲ^３０８は存在しない。Ｚ^４０１が酸素原子である場合はＲ^４０７およびＲ^４０８は存在せず、Ｚ^４０１が窒素原子である場合はＲ^４０８は存在しない。Ｚ^５０１が酸素原子である場合はＲ^５０９およびＲ^５１０は存在せず、Ｚ^５０１が窒素原子である場合はＲ^５１０は存在しない。

式（Ａ）中、α、β、およびγの少なくとも１つは置換基を有する基であり、該置換基は、ヒドロキシ基、チオール基、アミノ基、カルボキシル基、およびメトキシ基からなる群より選択される少なくとも１種の基である。ｌおよびｍは、それぞれ独立に、０または１であり、ｌとｍの和は、０以上２以下である。 Specific examples of the electron transport material are shown below. The compound shown by either of following formula (A1)-(A9) is mentioned.

In formulas (A1) to (A9), R ^{101 to} R ¹⁰⁶ , R ^{201 to} R ²¹⁰ , R ^{301 to} R ³⁰⁸ , R ^{401 to} R ⁴⁰⁸ , R ^{501 to} R ⁵¹⁰ , R ^{601 to} R ⁶⁰⁶ , R ^{701 to} R ⁷⁰⁸ , R ^{801 to} R ⁸¹⁰ , R ^{901 to} R ⁹⁰⁸ are each independently a monovalent group represented by the following formula (A), a hydrogen atom, a cyano group, a nitro group, a halogen atom, an alkoxycarbonyl group, a substituted or An unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic ring is shown. One of the carbon atoms in the main chain of the alkyl group may be replaced with O, S, NH, or NR ¹⁰⁰¹ (R ¹⁰⁰¹ is an alkyl group). The substituent of the substituted alkyl group is an alkyl group, an aryl group, an alkoxycarbonyl group, or a halogen atom. The substituent of the substituted aryl group or the substituted heterocyclic group is a halogen atom, a nitro group, a cyano group, an alkyl group, or a halogen-substituted alkyl group. Z ²⁰¹ , Z ³⁰¹ , Z ⁴⁰¹ and Z ⁵⁰¹ each independently represent a carbon atom, a nitrogen atom or an oxygen atom. When Z ²⁰¹ is an oxygen atom, R ²⁰⁹ and R ²¹⁰ are not present, and when Z ²⁰¹ is a nitrogen atom, R ²¹⁰ is not present. When Z ³⁰¹ is an oxygen atom, R ³⁰⁷ and R ³⁰⁸ are not present, and when Z ³⁰¹ is a nitrogen atom, R ³⁰⁸ is not present. When Z ⁴⁰¹ is an oxygen atom, R ⁴⁰⁷ and R ⁴⁰⁸ are not present, and when Z ⁴⁰¹ is a nitrogen atom, R ⁴⁰⁸ is not present. If Z ⁵⁰¹ is an oxygen atom absent ^{R 509} and ^{R 510,} when ^{Z 501} is a nitrogen atom ^{R 510} is absent.

In formula (A), at least one of α, β, and γ is a group having a substituent, and the substituent is selected from the group consisting of a hydroxy group, a thiol group, an amino group, a carboxyl group, and a methoxy group. Is at least one group. l and m are each independently 0 or 1, and the sum of l and m is 0 or more and 2 or less.

α is an alkylene group having 1-6 atoms in the main chain, an alkylene group having 1-6 atoms in the main chain substituted with an alkyl group having 1-6 carbon atoms, or a main chain substituted with a benzyl group. An alkylene group having 1 to 6 atoms, an alkylene group having 1 to 6 atoms in the main chain substituted with an alkoxycarbonyl group, or an alkylene group having 1 to 6 atoms in the main chain substituted with a phenyl group . These groups may have at least one group selected from the group consisting of a hydroxy group, a thiol group, an amino group, a carboxyl group, and a methoxy group as a substituent. One of the carbon atoms in the main chain of the alkylene group may be replaced by O or S or NH or NR ¹⁹ (R ¹⁹ is an alkyl group).

  β represents a phenylene group, an alkyl-substituted phenylene group having 1 to 6 carbon atoms, a nitro-substituted phenylene group, a halogen-substituted phenylene group, or an alkoxy group-substituted phenylene group. These groups may have at least one group selected from the group consisting of a hydroxy group, a thiol group, an amino group, a carboxyl group, and a methoxy group as a substituent.

γ represents a hydrogen atom, an alkyl group having 1 to 6 atoms in the main chain, or an alkyl group having 1 to 6 atoms in the main chain substituted with an alkyl group having 1 to 6 carbon atoms. These groups may have at least one group selected from the group consisting of a hydroxy group, a thiol group, an amino group, a carboxyl group, and a methoxy group as a substituent. One of the carbon atoms in the main chain of the alkyl group may be replaced with O or S or NH or NR ¹⁰⁰³ (R ¹⁰⁰³ is an alkyl group).

Among the electron transport materials represented by any of the above formulas (A1) to (A9), at least one of R ^{101 to} R ¹⁰⁶ , at least one of R ^{201 to} R ²¹⁰ , and at least one of R ^{301 to} R ³⁰⁸ , At least one of R ^{401 to} R ⁴⁰⁸ , at least one of R ^{501 to} R ⁵¹⁰ , at least one of R ^{601 to} R ⁶⁰⁶ , at least one of R ^{701 to} R ⁷⁰⁸ , at least one of R ^{801 to} R ⁸¹⁰ , R ^{901 to} R ⁹⁰⁸ are more preferably an electron transport material having a polymerizable functional group which is a monovalent group represented by the above formula (A).

  The electron transport layer is formed as follows. A coating film of an electron transport layer coating solution containing a composition containing an electron transport material having a polymerizable functional group, a thermoplastic resin having a polymerizable functional group, and a crosslinking agent is formed. And by heating-drying this coating film, a composition is polymerized and an electron carrying layer is formed. After the formation of the coating film, the crosslinking agent, the thermoplastic resin and the polymerizable functional group of the electron transport material are polymerized by a chemical reaction. By heating at that time, the chemical reaction is promoted and the polymerization is promoted. The heating temperature for heating and drying the coating film of the electron transport layer coating solution is preferably 100 to 200 ° C.

  In the table, A ′ is represented by the same structural formula as A, and specific examples of the monovalent group are shown in the columns A and A ′.

  Specific examples of the electron transport material having a polymerizable functional group are shown below.

  Table 1-1, Table 1-2, Table 1-3, Table 1-4, Table 1-5, and Table 1-6 show specific examples of the compound represented by the above formula (A1). In the table, when γ is “−”, it indicates a hydrogen atom, and the hydrogen atom of γ is included in the structure shown in the column of α or β.

  Specific examples of the compound represented by the above formula (A2) are shown in Table 2-1, Table 2-2, and Table 2-3. In the table, when γ is “−”, it indicates a hydrogen atom, and the hydrogen atom of γ is included in the structure shown in the column of α or β.

  Specific examples of the compound represented by the above formula (A3) are shown in Tables 3-1 and 3-2. In the table, when γ is “−”, it indicates a hydrogen atom, and the hydrogen atom of γ is included in the structure shown in the column of α or β.

  Specific examples of the compound represented by the above formula (A4) are shown in Tables 4-1 and 4-2. In the table, when γ is “−”, it indicates a hydrogen atom, and the hydrogen atom of γ is included in the structure shown in the column of α or β.

  Tables 5-1 and 5-2 show specific examples of the compound represented by the above formula (A5). In the table, when γ is “−”, it indicates a hydrogen atom, and the hydrogen atom of γ is included in the structure shown in the column of α or β.

  Table 6 shows specific examples of the compound represented by the above formula (A6). In the table, when γ is “−”, it indicates a hydrogen atom, and the hydrogen atom of γ is included in the structure shown in the column of α or β.

  Specific examples of the compound represented by the above formula (A7) are shown in Table 7-1, Table 7-2, and Table 7-3. In the table, when γ is “−”, it indicates a hydrogen atom, and the hydrogen atom of γ is included in the structure shown in the column of α or β.

  Specific examples of the compound represented by the formula (A8) are shown in Table 8-1, Table 8-2, and Table 8-3. In the table, when γ is “−”, it indicates a hydrogen atom, and the hydrogen atom of γ is included in the structure shown in the column of α or β.

  Tables 9-1 and 9-2 show specific examples of the compound represented by the formula (A9). In the table, when γ is “−”, it indicates a hydrogen atom, and the hydrogen atom of γ is included in the structure shown in the column of α or β.

  Derivatives having the structure of (A1) (derivatives of electron transport materials) are disclosed in, for example, US Pat. No. 4,442,193, US Pat. No. 4,992,349, US Pat. No. 5,468,583, Chemistry of materials, Vol. 19, no. It is possible to synthesize using a known synthesis method described in 11, 2703-2705 (2007). Moreover, it can synthesize | combine by reaction with the naphthalene tetracarboxylic dianhydride and monoamine derivative which can be purchased from Tokyo Chemical Industry Co., Ltd., Sigma-Aldrich Japan Co., Ltd., and Johnson Matthey Japan Incorporated.

The compound represented by (A1) has a polymerizable functional group (hydroxy group, thiol group, amino group, carboxyl group, and methoxy group) that can be polymerized with a crosslinking agent. As a method of introducing these polymerizable functional groups into the derivative having the structure of (A1), a method of directly introducing a polymerizable functional group into the derivative having the structure of (A1), the polymerizable functional group, or the polymerizable There is a method of introducing a structure having a functional group that can be a precursor of a functional group. Examples of the method described later include the following methods. A method of introducing a functional group-containing aryl group based on a halide of a naphthylimide derivative using, for example, a cross-coupling reaction using a palladium catalyst and a base. A method of introducing a functional group-containing alkyl group using a cross-coupling reaction using a FeCl ₃ catalyst and a base based on a halide of a naphthylimide derivative. There is a method of introducing a hydroxyalkyl group or a carboxyl group based on a halide of a naphthylimide derivative by allowing an epoxy compound or CO ₂ to act after lithiation. As a raw material for synthesizing a naphthylimide derivative, there is a method using the naphthalenetetracarboxylic dianhydride derivative or monoamine derivative having the polymerizable functional group or a functional group that can be a precursor of the polymerizable functional group.

  Derivatives having a structure of (A2) (electron transport material derivatives) can be purchased from, for example, Tokyo Chemical Industry Co., Ltd., Sigma-Aldrich Japan Co., Ltd., or Johnson Matthey Japan Inc. Further, based on phenanthrene derivatives or phenanthroline derivatives, Chem. Educator No. 6, 227-234 (2001), Journal of Synthetic Organic Chemistry, vol. 15, 29-32 (1957), Journal of Synthetic Organic Chemistry, vol. 15, 32-34 (1957). A dicyanomethylene group can also be introduced by reaction with malononitrile.

The compound represented by (A2) has a polymerizable functional group (hydroxy group, thiol group, amino group, carboxyl group, and methoxy group) that can be polymerized with a crosslinking agent. As a method for introducing these polymerizable functional groups into the derivative having the structure (A2), a method for directly introducing a polymerizable functional group into the derivative having the structure (A2), a polymerizable functional group or a polymerizable functional group. There is a method of introducing a structure having a functional group that can be a precursor of the above. Examples of the method described later include the following methods. A method of introducing a functional group-containing aryl group using a cross-coupling reaction using a palladium catalyst and a base based on a halide of phenanthrenequinone. A method of introducing a functional group-containing alkyl group using a cross-coupling reaction using a FeCl ₃ catalyst and a base based on a halide of phenanthrenequinone. Based on the halide of phenanthrenequinone, there is a method of introducing a hydroxyalkyl group or a carboxyl group by allowing an epoxy compound or CO ₂ to act after lithiation.

  Derivatives having a structure of (A3) (electron transport material derivatives) can be purchased from Tokyo Chemical Industry Co., Ltd., Sigma-Aldrich Japan Co., Ltd., or Johnson Matthey Japan Inc. Also, based on phenanthrene derivatives or phenanthroline derivatives, Bull. Chem. Soc. Jpn. , Vol. 65, 1006-1011 (1992). A dicyanomethylene group can also be introduced by reaction with malononitrile.

The compound represented by (A3) has a polymerizable functional group (hydroxy group, thiol group, amino group, carboxyl group, and methoxy group) that can be polymerized with a crosslinking agent. As a method of introducing these polymerizable functional groups into the derivative having the structure of the above formula (A3), a method of directly introducing a polymerizable functional group into the derivative having the structure of the formula (A3), a polymerizable functional group or a polymerization There is a method of introducing a structure having a functional group that can be a precursor of a functional functional group. Examples of the method described later include the following methods. A method of introducing a functional group-containing aryl group based on a halide of phenanthroline quinone using, for example, a cross-coupling reaction using a palladium catalyst and a base. A method of introducing a functional group-containing alkyl group using a cross-coupling reaction using a FeCl ₃ catalyst and a base based on a halide of phenanthroline quinone. Based on the halide of phenanthroline quinone, there is a method of introducing a hydroxyalkyl group or a carboxyl group by allowing an epoxy compound or CO ₂ to act after lithiation.

  A derivative having a structure of (A4) (a derivative of an electron transport material) can be purchased from, for example, Tokyo Chemical Industry Co., Ltd., Sigma Aldrich Japan Co., Ltd., or Johnson Matthey Japan Inc. Moreover, based on an acenaphthenequinone derivative | guide_body, it can also synthesize | combine with the synthesis | combining method of Tetrahedron Letters, 43 (16), 2991-2994 (2002), Tetrahedron Letters, 44 (10), 2087-2091 (2003). A dicyanomethylene group can also be introduced by reaction with malononitrile.

The compound represented by (A4) has a polymerizable functional group (hydroxy group, thiol group, amino group, carboxyl group, and methoxy group) that can be polymerized with a crosslinking agent. As a method for introducing these polymerizable functional groups into the derivative having the structure (A4), a method for directly introducing a polymerizable functional group into the derivative having the structure (A4), a polymerizable functional group or a polymerizable functional group. There is a method of introducing a structure having a functional group that can be a precursor of the above. Examples of the method described later include the following methods. A method of introducing a functional group-containing aryl group based on a halide of acenaphthenequinone, for example, using a cross-coupling reaction using a palladium catalyst and a base. A method of introducing a functional group-containing alkyl group using a cross-coupling reaction using a FeCl ₃ catalyst and a base based on a halide of acenaphthenequinone. Based on the halide of acenaphthenequinone, there is a method of introducing a hydroxyalkyl group or a carboxyl group by allowing an epoxy compound or CO ₂ to act after lithiation.

  A derivative having a structure of (A5) (a derivative of an electron transport material) can be purchased from, for example, Tokyo Chemical Industry Co., Ltd., Sigma Aldrich Japan Co., Ltd., or Johnson Matthey Japan Incorporated. Further, it can be synthesized using a fluorenone derivative and malononitrile by the synthesis method described in US Pat. No. 4,562,132. Moreover, it can also synthesize | combine using the synthesis method as described in Unexamined-Japanese-Patent No. 5-279582 and Unexamined-Japanese-Patent No. 7-70038 using a fluorenone derivative and an aniline derivative.

The compound represented by (A5) has a polymerizable functional group (hydroxy group, thiol group, amino group, carboxyl group, and methoxy group) that can be polymerized with a crosslinking agent. As a method of introducing these polymerizable functional groups into the derivative having the structure of (A5), a method of directly introducing a polymerizable functional group into the derivative having the structure of (A5), a polymerizable functional group or a polymerizable functional group There is a method of introducing a structure having a functional group that can be a precursor of the above. Examples of the method described later include the following methods. A method of introducing a functional group-containing aryl group based on a halide of fluorenone, for example, using a cross-coupling reaction using a palladium catalyst and a base. A method of introducing a functional group-containing alkyl group using a cross coupling reaction using a FeCl ₃ catalyst and a base based on a halide of fluorenone. There is a method of introducing a hydroxyalkyl group or a carboxyl group based on a halide of fluorenone by allowing an epoxy compound or CO ₂ to act after lithiation.

  Derivatives having a structure of (A6) (electron transport material derivatives) are synthesized using, for example, a synthesis method described in Chemistry Letters, 37 (3), 360-361 (2008), JP-A-9-151157. I can do it. Moreover, it can be purchased from Tokyo Chemical Industry Co., Ltd., Sigma Aldrich Japan Co., Ltd., or Johnson Matthey Japan Inc.

The compound represented by (A6) has a polymerizable functional group (hydroxy group, thiol group, amino group, carboxyl group, and methoxy group) that can be polymerized with a crosslinking agent. As a method for introducing these polymerizable functional groups into the derivative having the structure (A6), a method for directly introducing a polymerizable functional group into the derivative having the structure (A6), a polymerizable functional group or a polymerizable functional group. There is a method of introducing a structure having a functional group that can be a precursor of the above. Examples of the method described later include the following methods. A method of introducing a functional group-containing aryl group based on a naphthoquinone halide using, for example, a cross-coupling reaction using a palladium catalyst and a base. A method of introducing a functional group-containing alkyl group using a cross-coupling reaction using a FeCl ₃ catalyst and a base based on a naphthoquinone halide. There is a method of introducing a hydroxyalkyl group or a carboxyl group based on a naphthoquinone halide after lithiation and then allowing an epoxy compound or CO ₂ to act.

  Derivatives having a structure of (A7) (electron transport material derivatives) are disclosed in JP-A-1-206349, PPCI / Japan Hard Copy '98 Preliminary Collection p. 207 (1998). For example, a phenol derivative that can be purchased from Tokyo Chemical Industry Co., Ltd. or Sigma Aldrich Japan Co., Ltd. can be used as a raw material.

The compound represented by (A7) has a polymerizable functional group (hydroxy group, thiol group, amino group, carboxyl group, and methoxy group) that can be polymerized with a crosslinking agent. As a method of introducing these polymerizable functional groups into the derivative having the structure of (A7), there is a method of introducing a structure having a functional group that can be a polymerizable functional group or a precursor of the polymerizable functional group. Examples of this method include the following methods. A method of introducing a functional group-containing aryl group based on a diphenoquinone halide using, for example, a cross-coupling reaction using a palladium catalyst and a base. A method of introducing a functional group-containing alkyl group using a cross-coupling reaction using a FeCl ₃ catalyst and a base based on a diphenoquinone halide. There is a method of introducing a hydroxyalkyl group or a carboxyl group by allowing an epoxy compound or CO ₂ to act after lithiation.

  Derivatives having a structure of (A8) (electron transport material derivatives) are described in, for example, Journal of the American chemical society, Vol. 129, no. 49, 15259-78 (2007). Moreover, it can synthesize | combine by reaction with the perylene tetracarboxylic dianhydride and monoamine derivative which can be purchased from Tokyo Chemical Industry Co., Ltd., Sigma-Aldrich Japan Co., Ltd., and Johnson Matthey Japan Incorporated.

The compound represented by (A8) has a polymerizable functional group (hydroxy group, thiol group, amino group, carboxyl group, and methoxy group) that can be polymerized with a crosslinking agent. As a method of introducing these polymerizable functional groups into the derivative having the structure of (A8), a method of directly introducing a polymerizable functional group into the derivative having the structure of (A8), the polymerizable functional group, or the polymerizable There is a method of introducing a structure having a functional group that can be a precursor of a functional group. Examples of the method described later include the following methods. A method using a cross-coupling reaction using, for example, a palladium catalyst and a base based on a halide of a perylene imide derivative. There is a method of using a cross coupling reaction using a FeCl ₃ catalyst and a base based on a halide of a perylene imide derivative. As a raw material for synthesizing a perylene imide derivative, there is a method using the above-mentioned polymerizable functional group or a perylene tetracarboxylic dianhydride derivative or a monoamine derivative having a functional group that can be a precursor of the polymerizable functional group.

  A derivative having a structure of (A9) (a derivative of an electron transport material) can be purchased from, for example, Tokyo Chemical Industry Co., Ltd., Sigma-Aldrich Japan Co., Ltd., or Johnson Matthey Japan Inc.

The compound represented by (A9) has a polymerizable functional group (hydroxy group, thiol group, amino group, carboxyl group, and methoxy group) that can be polymerized with a crosslinking agent. As a method for introducing these polymerizable functional groups into the derivative having the structure (A9), a functional group that can be a polymerizable functional group or a precursor of the polymerizable functional group is added to the commercially available derivative having the structure (A9). There is a method of introducing a structure having a group. Examples of this method include the following methods. A method of introducing a functional group-containing aryl group based on an anthraquinone halide using, for example, a cross-coupling reaction using a palladium catalyst and a base. A method of introducing a functional group-containing alkyl group using a cross-coupling reaction using an FeCl ₃ catalyst and a base based on an anthraquinone halide. There is a method of introducing a hydroxyalkyl group or a carboxyl group by allowing an epoxy compound or CO ₂ to act after lithiation.

  Furthermore, the electron transport layer of the present invention is more preferably a three-dimensional cured film having a thermoplastic resin having a polymerizable functional group in addition to the electron transport material having a polymerizable functional group and a crosslinking agent. A thermoplastic resin having a polymerizable functional group, an electron transport material having a polymerizable functional group, and a cross-linking agent are bonded to each other by a functional group, so that electron transport is possible, and it is insoluble in the solvent of the upper layer (photosensitive layer) and is electrophotographic A cured film suitable as an electron transport layer of the photoreceptor can be formed. Furthermore, the presence of the thermoplastic resin having a polymerizable functional group makes a cured film having more uniform components. The reason is that the cross-linking agents are not adjacent to each other, and are bulky and have a large volume. Therefore, when the functional group of the cross-linking agent and the functional group of the resin are polymerized and cross-linked, the resin chains are pushed away, and the resin chains are aggregated. Is suppressed. Since the electron transport material having a polymerizable functional group is bonded to the cross-linking agent bonded to the resin chain without being unevenly distributed, the electron transport material is uniformly distributed in the film without being unevenly distributed. Will exist. For this reason, there is no portion where electrons stay, and it is considered that a higher level of positive memory suppression effect also occurs in the electron transport film.

  In this case, the thermoplastic resin having a polymerizable functional group preferably has a certain length of resin chain, and the weight average molecular weight (Mw) is more preferably 5000 or more and 300000 or less. If it is 5,000 or more and 300,000 or less, the uniformity of the structure derived from the crosslinking agent and the electron transport material is increased, and a higher effect of reducing positive memory can be obtained.

[Crosslinking agent]
Next, the crosslinking agent will be described.
As the crosslinking agent, an electron transport material having a polymerizable functional group, and a compound that polymerizes or crosslinks with a thermoplastic resin having a polymerizable functional group can be used. Specifically, compounds described in Shinzo Yamashita and Tosuke Kaneko “Crosslinking Agent Handbook” published by Taiseisha (1981) and the like can be used.

The crosslinking agent used for the electron transport layer is preferably an isocyanate compound or an amine compound. From the viewpoint of obtaining a film having a uniform polymer, and more preferably, an isocyanate group, blocked isocyanate group, or -CH ₂ -OR ¹ a monovalent group three to six with crosslinking agent represented (isocyanate compounds, amine Compound).
From the viewpoint of improving the uniformity of the electron transport layer, the molecular weight of the crosslinking agent is preferably in the range of 200 to 1300. More preferably, it is 1000 or less.

  The isocyanate compound is preferably an isocyanate compound having 3 to 6 isocyanate groups or blocked isocyanate groups. For example, triisocyanatebenzene, triisocyanatemethylbenzene, triphenylmethane triisocyanate, lysine triisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, naphthalene diisocyanate diphenylmethane diisocyanate, isophorone diisocyanate, xylylene diisocyanate, 2,2 , 4-trimethylhexamethylene diisocyanate, methyl-2,6-diisocyanatohexanoate, norbornane diisocyanate modified isocyanurate modified, biuret modified, allophanate modified, adduct modified with trimethylolpropane or pentaerythritol Etc. Among these, an isocyanurate modified body and an adduct modified body are more preferable.

The blocked isocyanate group is a group having a structure of —NHCOX ¹ (X ¹ is a protecting group). X ¹ may be any protecting group that can be introduced into an isocyanate group, but groups represented by the following formulas (H1) to (H7) are more preferable.

Below, the specific example of an isocyanate compound is shown.

式（Ｃ１）〜（Ｃ５）中、Ｒ^１１〜Ｒ^１６、Ｒ^２２〜Ｒ^２５、Ｒ^３１〜Ｒ^３４、Ｒ^４１〜Ｒ^４４、およびＲ^５１〜Ｒ^５４は、それぞれ独立に、水素原子、ヒドロキシ基、アシル基または−ＣＨ_２−ＯＲ^１を示される１価の基を示し、Ｒ^１１〜Ｒ^１６の少なくとも１つ、Ｒ^２２〜Ｒ^２５の少なくとも１つ、Ｒ^３１〜Ｒ^３４の少なくとも１つ、Ｒ^４１〜Ｒ^４４の少なくとも１つ、およびＲ^５１〜Ｒ^５４の少なくとも１つは、−ＣＨ_２−ＯＲ^１を示される１価の基である。Ｒ^１は、水素原子または炭素数１以上１０以下のアルキル基を示す。アルキル基としてはメチル基、エチル基、プロピル基（ｎ−プロピル基、ｉｓｏ−プロピル基）、ブチル基（ｎ−ブチル基、ｉｓｏ−ブチル基、ｔｅｒｔ−ブチル基）などが、重合性の観点から好ましい。Ｒ^２１は、アリール基、アルキル基置換のアリール基、シクロアルキル基、またはアルキル基置換のシクロアルキル基を示す。 The amine compound is at least selected from the group consisting of compounds represented by any of the formulas (C1) to (C5) and oligomers of compounds represented by any of the following formulas (C1) to (C5). One type is preferable.

In formulas (C1) to (C5), R ^{11 to} R ¹⁶ , R ^{22 to} R ²⁵ , R ^{31 to} R ³⁴ , R ^{41 to} R ⁴⁴ , and R ^{51 to} R ⁵⁴ are each independently a hydrogen atom, hydroxy A monovalent group represented by a group, an acyl group or —CH ₂ —OR ¹ ; at least one of R ^{11 to} R ¹⁶ ; at least one of R ^{22 to} R ²⁵ ; and at least one of R ^{31 to} R ^34. , R ^{41 to} R ⁴⁴ , and at least one of R ^{51 to} R ⁵⁴ are a monovalent group represented by —CH ₂ —OR ¹ . R ¹ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group (n-propyl group, iso-propyl group), a butyl group (n-butyl group, iso-butyl group, tert-butyl group), and the like from the viewpoint of polymerization. preferable. R ²¹ represents an aryl group, an alkyl group-substituted aryl group, a cycloalkyl group, or an alkyl group-substituted cycloalkyl group.

  Specific examples of the compound represented by any one of formulas (C1) to (C5) are shown below. Moreover, you may contain the oligomer (multimer) of the compound shown by either of Formula (C1)-(C5). From the viewpoint of obtaining a uniform polymer film, the compound (monomer) represented by any one of formulas (C1) to (C5) is preferably contained in an amount of 10% by mass or more in the total mass of the amine compound. .

  The degree of polymerization of the above-mentioned multimer is preferably 2 or more and 100 or less. Moreover, the above-mentioned multimer and monomer can be used in combination of two or more.

  As a generally commercially available compound represented by the above formula (C1), for example, Super Melami No. 90 (manufactured by NOF Corporation), Super Becamine (R) TD-139-60, L-105-60, L127-60, L110-60, J-820-60, G-821-60 (manufactured by DIC) , Uban 2020 (Mitsui Chemicals), Sumitex Resin M-3 (Sumitomo Chemical Industries), Nicalak MW-30, MW-390, MX-750LM (manufactured by Nippon Carbide), and the like. Examples of generally commercially available compounds represented by the above formula (C2) include, for example, “Superbecamine (R) L-148-55, 13-535, L-145-60, TD-126. (Manufactured by DIC Corporation), Nicarak BL-60, BX-4000 (manufactured by Nippon Carbide Corporation), etc. Examples of generally commercially available compounds represented by the above formula (C3) include: Nicarac MX-280 (manufactured by Nippon Carbide Co., Ltd.), etc. Examples of generally commercially available compounds represented by the above formula (C4) include Nicarak MX-270 (manufactured by Nippon Carbide Co., Ltd.). Examples of generally commercially available compounds represented by the above formula (C5) include Nicalac MX-290 (manufactured by Nippon Carbide).

Specific examples of the compound represented by any one of formulas (C1) to (C5) are shown below.

式（Ｄ）中、Ｒ^６１は、水素原子またはアルキル基を示す。Ｙ^１は、単結合、アルキレン基またはフェニレン基を示す。Ｗ^１は、ヒドロキシ基、チオール基、アミノ基、カルボキシル基、またはメトキシ基を示す。） 〔resin〕
Next, a thermoplastic resin having a polymerizable functional group will be described. As the thermoplastic resin having a polymerizable functional group, a thermoplastic resin having a structural unit represented by the following formula (D) (hereinafter also referred to as resin D) is preferable.

In the formula (D), R ⁶¹ represents a hydrogen atom or an alkyl group. Y ¹ represents a single bond, an alkylene group or a phenylene group. W ¹ represents a hydroxy group, a thiol group, an amino group, a carboxyl group, or a methoxy group. )

  Resin D polymerizes a monomer having a polymerizable functional group (hydroxy group, thiol group, amino group, carboxyl group, or methoxy group) that can be purchased from, for example, Sigma-Aldrich Japan Co., Ltd. or Tokyo Chemical Industry Co., Ltd. Can be obtained.

  Moreover, it is also possible to generally purchase as resin. Examples of the resin that can be purchased include polyether polyol resins such as AQD-457 and AQD-473 manufactured by Nippon Polyurethane Industry Co., Ltd., Sannics GP-400 and GP-700 manufactured by Sanyo Chemical Industries, Ltd., and Hitachi Chemical. Industrial Co., Ltd., Phthalkid W2343, DIC Corporation, Watersol S-118, CD-520, Beckolite M-6402-50, M-6201-40IM, Harima Chemicals Co., Ltd., Hollidip WH-1188, Japan Polyester polyol resins such as Eupica ES3604 and ES6538, Polyacrylic polyol resins such as DIC Corporation, Bernock WE-300 and WE-304, and polyvinyl alcohols such as Kuraray Kuraraypoval PVA-203 Resin, BX-1, BM-1 manufactured by Sekisui Chemical Co., Ltd. Polyvinyl acetal resins such as KS-1 and KS-5, polyamide resins such as Toraysin FS-350 manufactured by Nagase ChemteX Corporation, Aqualic manufactured by Nippon Shokubai Co., Ltd., Finelex SG2000 manufactured by Lead City Corporation, etc. Carboxyl group-containing resins, DIC Corporation, polyamine resins such as racamide, and Toray Industries Inc. QE-340M polythiol resins. Among these, polyvinyl acetal resins, polyester polyol resins and the like are more preferable from the viewpoints of polymerizability and uniformity of the electron transport layer.

  The weight average molecular weight (Mw) of the resin D is preferably in the range of 5,000 to 400,000, more preferably in the range of 5,000 to 300,000. The reason is that aggregation of the molecular chains of the resin D is suppressed when the above-mentioned crosslinking agent is polymerized (crosslinked) with the resin D. And since aggregation of the resin molecular chains is suppressed and the above-mentioned uneven distribution of the cross-linking agent is suppressed, the electron transport material site can be uniformly present in the undercoat layer without being unevenly distributed. it is conceivable that.

  Examples of the quantitative method for the polymerizable functional group in the resin include the following methods. Titration of carboxyl group using potassium hydroxide, titration of amino group using sodium nitrite, titration of hydroxy group using acetic anhydride and potassium hydroxide, 5,5′-dithiobis (2-nitrobenzoic acid) Titration of the thiol group used. Moreover, the calibration curve method obtained from the IR spectrum of the sample which changed the polymeric functional group introduction ratio is mentioned.

  Table 10 below shows specific examples of the resin D.

  The electron transport material having a polymerizable functional group is 30% by mass or more and 70% by mass or less based on the total mass of the composition including the electron transport material having a polymerizable functional group, a crosslinking agent, and a resin having a polymerizable functional group. Preferably there is.

The ratio of the functional group of the crosslinking agent (isocyanate group or monovalent group represented by —CH ₂ —OR ¹ ) to the total of the polymerizable functional group of the resin and the polymerizable functional group of the electron transport material is The ratio of 1: 0.5 to 1: 3.0 is preferable because the ratio of the functional group to be reacted is increased. In this case, the electron transport layer is obtained by analyzing the ratio of each atom in the depth direction by ESCA, and the standard deviations of the carbon atom ratio, the nitrogen atom ratio, and the oxygen atom ratio are expressed by the above formulas (1) to (3). Is satisfied. And since an electron transport structure exists uniformly, without aggregating in an electron carrying layer, it is preferable.

  Further, the electron transport layer may contain roughened particles as long as the above formulas (1) to (3) are satisfied. Examples of the roughened particles include curable resin particles such as curable rubber, polyurethane resin, epoxy resin, alkyd resin, phenol resin, polyester resin, silicone resin, and acrylic-melamine resin. In addition, metal oxide particles such as titanium oxide, zinc oxide, tin oxide, and zirconium oxide particles may be mentioned. In order to determine the interface between the conductive layer and the electron transport layer, the conductive particles included in the conductive layer It is preferable that it is not the metal oxide particle which has the same metal atom. Further, for the purpose of improving the leveling effect and adhesion, silicone oil, surfactant, silane compound and the like may be contained in a range satisfying the above formulas (1) to (3). The content of these additives is preferably 5% by mass or less with respect to the total mass of the electron transport layer from the viewpoint of the uniformity of the electron transport layer. The film thickness of the electron transport layer of the present invention is preferably 0.1 μm or more and 5.0 μm or less.

The compound and polymer contained in the electron transport layer were confirmed by the following method.
-Mass spectrometry The molecular weight was measured using a mass spectrometer (MALDI-TOF MS: ultraflex manufactured by Bruker Daltonics Co., Ltd.) under the conditions of acceleration voltage: 20 kV, mode: Reflector, molecular weight standard product: fullerene C60. It confirmed with the obtained peak top value.
-NMR analysis In 1,1,2,2-tetrachloroethane (d2) or dimethyl sulfoxide (d6), ¹ H-NMR, ¹³ C-NMR analysis (FT-NMR: manufactured by JEOL Ltd.) at 120 ° C The structure was confirmed by JNM-EX400 type).
-GPC analysis It measured with the gel permeation chromatography "HLC-8120" by Tosoh Corporation, and computed in polystyrene conversion.

[Support]
The support is preferably a conductive one (conductive support). For example, a support made of a metal such as aluminum, nickel, copper, gold, iron, or an alloy can be used. A support in which a thin film of metal such as aluminum, silver, or gold is formed on an insulating support such as polyester resin, polycarbonate resin, polyimide resin, or glass, or a thin film of conductive material such as indium oxide or tin oxide is formed. A support is mentioned.

  The surface of the support may be subjected to electrochemical treatment such as anodization, wet honing treatment, blast treatment, cutting treatment, etc. in order to improve electrical characteristics and suppress interference fringes.

  A conductive layer may be provided between the support and the electron transport layer. The conductive layer can be obtained by forming a coating film of a coating liquid for conductive layer in which conductive particles are dispersed in a resin on a support and drying it. Examples of the conductive particles include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, and silver, and metal oxide powder such as conductive tin oxide and ITO. Can be mentioned. The conductive layer may be provided in the order of the electron transport layer and the conductive layer.

  Examples of the resin include polyester resin, polycarbonate resin, polyvinyl butyral resin, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, and alkyd resin.

  Examples of the solvent for the conductive layer coating solution include ether solvents, alcohol solvents, ketone solvents, and aromatic hydrocarbon solvents. The thickness of the conductive layer is preferably 0.2 μm or more and 40 μm or less, more preferably 1 μm or more and 35 μm or less, and even more preferably 5 μm or more and 30 μm or less.

(Photosensitive layer)
A charge generation layer is provided on the electron transport layer.
Charge generation materials include azo pigments, perylene pigments, anthraquinone derivatives, anthanthrone derivatives, dibenzpyrenequinone derivatives, pyranthrone derivatives, violanthrone derivatives, isoviolanthrone derivatives, indigo derivatives, thioindigo derivatives, metal phthalocyanines, metal-free phthalocyanines, etc. Phthalocyanine pigments and bisbenzimidazole derivatives. Among these, at least one of an azo pigment and a phthalocyanine pigment is preferable. Among the phthalocyanine pigments, oxytitanium phthalocyanine, chlorogallium phthalocyanine, and hydroxygallium phthalocyanine are preferable.

  When the photosensitive layer is a laminated photosensitive layer, examples of the binder resin used for the charge generation layer include styrene, vinyl acetate, vinyl chloride, acrylic ester, methacrylic ester, vinylidene fluoride, and trifluoroethylene. Polymers and copolymers of vinyl compounds, polyvinyl alcohol resins, polyvinyl acetal resins, polycarbonate resins, polyester resins, polysulfone resins, polyphenylene oxide resins, polyurethane resins, cellulose resins, phenol resins, melamine resins, silicon resins, epoxy resins, etc. Is mentioned. Among these, polyester resin, polycarbonate resin, and polyvinyl acetal resin are preferable, and polyvinyl acetal is more preferable.

In the charge generation layer, the ratio of the charge generation material to the binder resin (charge generation material / binder resin) is preferably in the range of 10/1 to 1/10, and in the range of 5/1 to 1/5. It is more preferable that Examples of the solvent used in the charge generation layer coating solution include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents.
The thickness of the charge generation layer is preferably 0.05 μm or more and 5 μm or less.

When the photosensitive layer is a laminated photosensitive layer, a hole transport layer is formed on the charge generation layer.
Examples of the hole transport material include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, benzidine compounds, triarylamine compounds, and triphenylamine. Or the polymer which has group derived from these compounds in a principal chain or a side chain is mentioned. Among these, a triarylamine compound, a benzidine compound, or a styryl compound is preferable.

  Examples of the binder resin used for the hole transport layer include a polyester resin, a polycarbonate resin, a polymethacrylate resin, a polyarylate resin, a polysulfone resin, and a polystyrene resin. Among these, polycarbonate resin and polyarylate resin are preferable. Moreover, as these molecular weight, the range of a weight average molecular weight (Mw) = 10,000-300,000 is preferable.

  In the hole transport layer, the ratio of the hole transport material to the binder resin (hole transport material / binder resin) is preferably 10/5 to 5/10, and more preferably 10/8 to 6/10.

  The thickness of the hole transport layer is preferably 3 μm or more and 40 μm or less. From the viewpoint of the film thickness with the electron transport layer, it is more preferably 5 μm or more and 16 μm or less. Examples of the solvent used in the coating liquid for the hole transport layer include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents.

  Note that another layer such as a second undercoat layer not containing the polymer according to the present invention may be provided between the support and the electron transport layer or between the electron transport layer and the charge generation layer. Good.

  A surface protective layer may be formed on the hole transport layer. The surface protective layer contains conductive particles or a charge transport material and a binder resin. The surface protective layer may further contain an additive such as a lubricant. Further, the binder resin itself of the protective layer may have conductivity and charge transport property. In that case, the protective layer may not contain conductive particles other than the resin or a charge transport material. Further, the binder resin of the protective layer may be a thermoplastic resin or a curable resin that is polymerized by heat, light, radiation (electron beam, etc.), or the like.

  As a method of forming each of the above layers, a method of forming by coating a coating solution obtained by dissolving and / or dispersing materials constituting each layer in a solvent, and drying and / or curing the obtained coating film. Is preferred. Examples of the method for applying the coating liquid include a dip coating method (dip coating method), a spray coating method, a curtain coating method, and a spin coating method. Among these, the dip coating method is preferable from the viewpoints of efficiency and productivity.

[Process cartridge and electrophotographic apparatus]
FIG. 3 shows a schematic configuration of an electrophotographic apparatus having a process cartridge provided with an electrophotographic photosensitive member.
In FIG. 3, reference numeral 1 denotes a cylindrical electrophotographic photosensitive member, which is driven to rotate at a predetermined peripheral speed in the direction of the arrow about the shaft 2. The surface (circumferential surface) of the electrophotographic photosensitive member 1 that is rotationally driven is uniformly charged to a predetermined positive or negative potential by a charging unit 3 (primary charging unit: charging roller or the like). Next, it receives exposure light (image exposure light) 4 from exposure means (not shown) such as slit exposure or laser beam scanning exposure. In this way, electrostatic latent images corresponding to the target image are sequentially formed on the surface of the electrophotographic photosensitive member 1.

  The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is then developed with toner contained in the developer of the developing means 5 to become a toner image. Next, the toner image formed and supported on the surface of the electrophotographic photosensitive member 1 is sequentially transferred onto a transfer material (such as paper) P by a transfer bias from a transfer unit (such as a transfer roller) 6. The transfer material P is taken out from the transfer material supply means (not shown) between the electrophotographic photoreceptor 1 and the transfer means 6 (contact portion) in synchronization with the rotation of the electrophotographic photoreceptor 1 and fed. Is done.

  The transfer material P that has received the transfer of the toner image is separated from the surface of the electrophotographic photosensitive member 1 and introduced into the fixing means 8 to receive the image fixing, and is printed out as an image formed product (print, copy). Is done.

  The surface of the electrophotographic photosensitive member 1 after the transfer of the toner image is cleaned by receiving a developer (toner) remaining after transfer by a cleaning means (cleaning blade or the like) 7. Next, after being subjected to charge removal processing by pre-exposure light (not shown) from pre-exposure means (not shown), it is repeatedly used for image formation. As shown in FIG. 3, when the charging unit 3 is a contact charging unit using a charging roller or the like, pre-exposure is not necessarily required.

  Among the electrophotographic photosensitive member 1, charging unit 3, developing unit 5, transfer unit 6, and cleaning unit 7, a plurality of components are selected and placed in a container and integrally combined as a process cartridge. To do. The process cartridge may be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. In FIG. 3, the electrophotographic photosensitive member 1, the charging unit 3, the developing unit 5 and the cleaning unit 7 are integrally supported to form a cartridge, and the electrophotographic apparatus is used by using a guide unit 10 such as a rail of the electrophotographic apparatus main body. The process cartridge 9 is detachable from the main body.

Hereinafter, the present invention will be described in more detail with reference to examples. In the examples, “part” means “part by mass”.
First, synthesis examples of the electron transporting compound according to the present invention will be shown.

(Synthesis Example 1)
200 parts of dimethylacetamide, 5.4 parts of naphthalenetetracarboxylic dianhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) and 4 parts of 2-methyl 6-ethylaniline (manufactured by Tokyo Chemical Industry Co., Ltd.) under a nitrogen atmosphere Then, 3 parts of 2-amino 1-butanol was added and stirred at room temperature for 1 hour to prepare a solution. After preparing the solution, the mixture was refluxed for 8 hours. The precipitate was filtered off and recrystallized from ethyl acetate to obtain 1.0 part of Compound A101.

(Synthesis Example 2)
In a nitrogen atmosphere, 5.4 parts of naphthalenetetracarboxylic dianhydride (Tokyo Chemical Industry Co., Ltd.) and 2-aminobutyric acid (Tokyo Chemical Industry Co., Ltd.) were added to 200 parts of dimethylacetamide. )) 5 parts were added and stirred at room temperature for 1 hour to prepare a solution. After preparing the solution, the mixture was refluxed for 8 hours. The precipitate was filtered off and recrystallized from ethyl acetate to obtain 4.6 parts of Compound A129.

(Synthesis Example 3)
In a nitrogen atmosphere, 200 parts of dimethylacetamide, 5.4 parts of naphthalenetetracarboxylic dianhydride, 4.5 parts of 2,6 diethylaniline (manufactured by Tokyo Chemical Industry Co., Ltd.), 4 parts of 4-aminobenzenethiol The mixture was stirred at room temperature for 1 hour to prepare a solution. After preparing the solution, the mixture was refluxed for 8 hours. The precipitate was filtered off and recrystallized from ethyl acetate to obtain 1.3 parts of Compound A114.

(Synthesis Example 4)
To a mixed solvent of 100 parts of toluene and 50 parts of ethanol, 2.8 parts of 4- (hydroxymethyl) phenylboronic acid manufactured by Aldrich and phenanthrenequinone manufactured by Sigma-Aldrich Japan Co., under a nitrogen atmosphere, Chem. Educator No. After adding 7.4 parts of 3,6-dibromo-9,10-phenanthrene dione synthesized by the synthesis method described in US Pat. No. 6,227-234 (2001) and adding 100 parts of a 20% aqueous sodium carbonate solution dropwise, tetrakis (tri After adding 0.55 part of phenylphosphine) palladium (0), the mixture was refluxed for 2 hours. After the reaction, the organic phase was extracted with chloroform, washed with water, and dried over anhydrous sodium sulfate. After removing the solvent under reduced pressure, the residue was purified by silica gel chromatography to obtain 3.2 parts of Compound A216.

(Synthesis Example 5)
2,7-Dibromo-9,10-phenanthroline was prepared in the same manner as in Synthesis Example 4 except that 2.8 parts of 3-aminophenylboronic acid monohydrate and phenanthroline quinone (manufactured by Sigma-Aldrich Japan Co., Ltd.) were used. 7.4 parts of quinone were synthesized. 7.4 parts of 2,7-dibromo-9,10-phenanthrolinequinone is added to a mixed solvent of 100 parts of toluene and 50 parts of ethanol, and 100 parts of 20% aqueous sodium carbonate solution is added dropwise, followed by tetrakis (triphenylphosphine) palladium. After adding 0.55 parts of (0), the mixture was refluxed for 2 hours. After the reaction, the organic phase was extracted with chloroform, washed with water, and dried over anhydrous sodium sulfate. After removing the solvent under reduced pressure, the residue was purified by silica gel chromatography to obtain 2.2 parts of Compound A316.

(Synthesis Example 6)
200 parts of dimethylacetamide, 7.4 parts of perylenetetracarboxylic dianhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) and 4 parts of 2,6 diethylaniline (manufactured by Tokyo Chemical Industry Co., Ltd.) under a nitrogen atmosphere, 2 parts -4 parts of aminophenylethanol was added and stirred at room temperature for 1 hour to prepare a solution. After preparing the solution, the mixture was refluxed for 8 hours, and the precipitate was filtered off and recrystallized from ethyl acetate to obtain 5.0 parts of Compound A803.

(Synthesis Example 7)
To 200 parts of dimethylacetamide, 5.4 parts of naphthalenetetracarboxylic dianhydride and 5.2 parts of leucinol were added under a nitrogen atmosphere, stirred at room temperature for 1 hour, and then refluxed for 7 hours. Dimethylacetamide was removed by distillation under reduced pressure, and then recrystallization was performed with ethyl acetate to obtain 5.0 parts of Compound A168.

(Synthesis Example 8)
Under a nitrogen atmosphere, 5.4 parts of naphthalenetetracarboxylic dianhydride, 2.6 parts of leucinol and 2.7 parts of 2- (2-aminoethylthio) ethanol are added to 200 parts of dimethylacetamide at room temperature for 1 hour. After stirring, the mixture was refluxed for 7 hours. Dimethylacetamide was removed from the resulting black brown solution by distillation under reduced pressure, and then dissolved in a mixed solution of ethyl acetate / toluene.
After separation by silica gel column chromatography (developing solvent: ethyl acetate / toluene), the fraction containing the target compound is concentrated, and the resulting crystals are recrystallized with a toluene / hexane mixed solution to obtain 2.5 parts of compound A163. It was.
Next, production and evaluation of an electrophotographic photoreceptor will be described.

Example 1
An aluminum cylinder (JIS-A3003, aluminum alloy) having a length of 260.5 mm and a diameter of 30 mm was used as a support (conductive support).

  Next, 50 parts of titanium oxide particles coated with oxygen-deficient tin oxide (powder resistivity: 120 Ω · cm, tin oxide coverage: 40%), phenol resin (Pryofen J-325, Dainippon) Ink Chemical Industry Co., Ltd., resin solid content: 60%.) 40 parts and 50 parts of methoxypropanol were placed in a sand mill using glass beads with a diameter of 1 mm, and subjected to a dispersion treatment for 3 hours. (Dispersion) was prepared. The conductive layer coating solution was dip-coated on a support, and the resulting coating film was dried and thermally polymerized at 150 ° C. for 30 minutes to form a conductive layer having a thickness of 16 μm.

  The average particle diameter of the titanium oxide particles coated with oxygen-deficient tin oxide in the coating liquid for the conductive layer was measured using a particle size distribution meter (trade name: CAPA700) manufactured by Horiba, Ltd., and tetrahydrofuran as a dispersion medium. , And measured by centrifugal sedimentation at a rotational speed of 5000 rpm. As a result, the average particle size was 0.31 μm.

  Next, 4 parts of compound (A101), 7.3 parts of crosslinking agent (B1: protecting group (H1) = 5.1: 2.2 (mass ratio)), 0.9 part of resin (D1), 0.05 parts of dioctyltin laurate was dissolved in a mixed solvent of 100 parts of dimethylacetamide and 100 parts of methyl ethyl ketone to prepare a coating solution for an electron transport layer. This electron transport layer coating solution is applied onto the conductive layer by dip coating, and the resulting coating film is heated at 160 ° C. for 40 minutes to polymerize, thereby forming an electron transport layer (0.53 μm thick cured film). Undercoat layer) was formed.

  The content of the electron transport material with respect to the total mass of the electron transport material, the crosslinking agent, and the resin in the coating solution for the electron transport layer was 33% by mass.

  Next, Bragg angles (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction of 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 ° and 10 parts of crystalline hydroxygallium phthalocyanine crystal (charge generating material) having a strong peak at 28.3 °, 5 parts of polyvinyl butyral resin (trade name: S-REC BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 250 parts of cyclohexanone Was placed in a sand mill using glass beads having a diameter of 1 mm and dispersed for 1.5 hours. Next, 250 parts of ethyl acetate was added thereto to prepare a charge generation layer coating solution.

  This charge generation layer coating solution was dip-coated on the electron transport layer, and the resulting coating film was dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.15 μm.

Next, 8 parts of an amine compound (hole transport material) represented by the following structural formula (9), a repeating structural unit represented by the following formula (10-1), and a following formula (10-2) By dissolving 10 parts of a polyester resin (I) having a repeating structural unit at a ratio of 5/5 and having a weight average molecular weight (Mw) of 100,000 in a mixed solvent of 40 parts of dimethoxymethane and 60 parts of o-xylene. Then, a coating solution for a hole transport layer was prepared. This hole transport layer coating solution was dip-coated on the charge generation layer, and the resulting coating film was dried at 120 ° C. for 40 minutes to form a hole transport layer having a thickness of 15 μm.

  Thus, a positive memory and an electrophotographic photosensitive member for potential fluctuation evaluation were manufactured. Further, another electrophotographic photosensitive member was produced in the same manner as described above, and used as an electrophotographic photosensitive member for determination.

(Judgment test)
The electrophotographic photoreceptor for determination is immersed in a mixed solvent of 40 parts of dimethoxymethane and 60 parts of o-xylene for 5 minutes to peel off the hole transport layer, and further immersed in a cyclohexanone solvent for 5 minutes to form a charge generation layer. Was also peeled off. Then, it was dried at 100 ° C. for 10 minutes. Using the FTIR-ATR method, it was confirmed that the components of the hole transport layer and the charge generation layer did not remain on the surface of the electron transport layer. This electrophotographic photosensitive member was allowed to stand in an environment of temperature 25 ° C. and humidity 50% RH for 24 hours, and then the central portion (position 130 mm from the end) of the electrophotographic photosensitive member was cut into a 1 cm square to prepare a sample for ESCA measurement. .

  As described above, the ESCA measurement was performed by etching with Ion gun C60 (hereinafter also referred to as C60) from the measurement of the surface of the electron transport layer. Thereafter, the measurement of the ratio of each atom was repeated, and analysis of the ratio of each atom in the depth direction by C60 was performed until the conductive layer was reached (Ti contained in the titanium oxide particles was detected). From the etching time up to 30 minutes, a total of 10 points consisting of 8 points that divide the thickness of the electron transport layer into 9 parts in the depth direction were selected. The carbon atom ratio (atoms%), the nitrogen atom ratio (atoms%), and the oxygen atom ratio (atoms%) obtained at each of the 10 measurement points, and the standard deviation σ of the ratio of each atom calculated from them Table 11 shows (C), σ (N), and σ (O). In addition to carbon atoms, nitrogen atoms and oxygen atoms, atoms constituting the electron transport layer (cured film) include halogen atoms such as fluorine atoms, chlorine atoms and bromine atoms, silicon atoms, phosphorus atoms and sulfur atoms. Atomic measurements were also performed. Then, the total of the ratio of carbon atoms, the ratio of nitrogen atoms, and the ratio of oxygen atoms (composition ratio) to the ratio of all atoms excluding hydrogen atoms was measured as the total content ratio (atoms%). The results are shown in Table 12.

  In addition, the hole transport layer and the charge generation layer of the electrophotographic photosensitive member for judgment were not peeled off with a solvent, and the central portion (position 130 mm from the end) of the electrophotographic photosensitive member was cut into a 1 cm square to prepare an ESCA measurement sample. did. When this sample was similarly analyzed from the top of the charge transport layer and the ratio of each atom in the depth direction was analyzed by ESCA, the same results as those obtained when the charge generation layer and the hole transport layer were peeled off were obtained. In this case, the surface of the electron transport layer was used when the detection of gallium atoms in the charge generation material was stopped.

(Plus memory and potential fluctuation evaluation)
The manufactured positive memory and electrophotographic photosensitive member for potential fluctuation evaluation are converted into a laser beam printer (trade name: LBP-2510) manufactured by Canon Inc. (pre-exposure OFF, primary charging: roller contact DC charging, process (Evaluation of potential fluctuation and output image (plus memory)). Details are as follows.

1. Plus Memory Under the environment of temperature 23 ° C and humidity 50% RH, the cyan process cartridge for the laser beam printer was modified and a potential probe (model6000B-8: manufactured by Trek Japan Co., Ltd.) was developed. Installed. The manufactured electrophotographic photosensitive member was mounted on a cyan process cartridge, and the electric potential at the center of the electrophotographic photosensitive member was measured using a surface potentiometer (model 344: manufactured by Trek Japan Co., Ltd.). Further, the surface voltage of the electrophotographic photosensitive member was set such that the charging voltage and the amount of exposure light were such that the dark part potential (Vd) was −600 V and the light part potential (Vl) was −200 V. Next, +300 V was applied as DC charging from an external power source (Trek High Voltage Power Supply, Model 610C) for 5 minutes from the charging roller while rotating the electrophotographic photosensitive member in the laser beam printer. After 5 minutes, the dark portion potential (Vd) and the light portion potential (Vl) before applying the positive charge (+300 V) are set to the charging voltage and the exposure light amount. After 5 minutes, the dark portion potential and the light portion potential after applying the positive charge (+300 V). Measurements were made. Then, the bright portion potential difference before and after the application of the positive charge was measured as a positive memory ΔVl. The results are shown in Table 12.
Next, the above-described electrophotographic photosensitive member was attached to the cyan process cartridge of the laser beam printer, the process cartridge was attached to the cyan process cartridge station, and images were output before and after applying the positive charge. Halftone images were output one by one before and after applying a positive charge.
As shown in FIG. 4, the halftone image is a halftone image having a 1-dot Keima pattern.
The positive memory image is evaluated by measuring the density difference between the image density of the halftone image of the 1-dot Keima pattern before applying the positive charge and the image density of the halftone image of the 1-dot Keima pattern after applying the positive charge. went. Using a spectral densitometer (trade name: X-Rite 504/508, manufactured by X-Rite Co., Ltd.), a density difference was measured at 10 points in a halftone image of one dot Keima pattern. The average of a total of 10 points was calculated. Similarly, the average value of the density of a total of 10 points was also calculated in the halftone image when no plus charge was applied. Table 12 shows the difference in image density between the two. The higher the density of the halftone image, the stronger the positive memory. The smaller the density difference (Macbeth density difference), the more positive memory is suppressed. When the plus-memory image density difference is 0.10 or more, there is a clear difference, and when it is less than 0.10, there is no apparent difference.

2. Electric potential fluctuation Under the environment of temperature 23 ° C and humidity 5% RH, the cyan process cartridge of the laser beam printer was modified, and the electric potential probe (model6000B-8: manufactured by Trek Japan Co., Ltd.) was installed at the development position. Installed. The potential at the center of the electrophotographic photosensitive member was measured using a surface potentiometer (model 344: manufactured by Trek Japan Co., Ltd.). Further, the charging voltage and the amount of exposure light were set so that the dark portion potential (Vd) was −600 V and the light portion potential (Vl) was −200 V.
With the exposure amount set in that state (the state where the potential probe is in the developing unit), 2000 continuous sheets were repeatedly used. Table 12 shows Vd and Vl after 2000 sheets.

(Examples 2 to 5)
The thickness of the electron transport layer was changed from 0.53 μm to 0.38 μm (Example 2), 0.25 μm (Example 3), 0.20 μm (Example 4), and 0.15 μm (Example 5). Produced an electrophotographic photoreceptor in the same manner as in Example 1 and evaluated in the same manner. The results are shown in Table 12.

(Example 6)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 12.
4 parts of electron transport material (A101), 5.5 parts of isocyanate compound (B1: protecting group (H1) = 5.1: 2.2 (mass ratio)), 0.3 part of resin (D1), dioctyl as catalyst 0.05 part of tin laurate was dissolved in a mixed solvent of 100 parts of dimethylacetamide and 100 parts of methyl ethyl ketone to prepare a coating solution for an electron transport layer. The electron transport layer coating solution is dip-coated on the conductive layer, and the resulting coating film is heated for 40 minutes at 160 ° C. to polymerize the electron transport layer, which is a cured film having a thickness of 0.61 μm. Formed.

(Examples 7 to 9)
Electrons were transported in the same manner as in Example 6 except that the thickness of the electron transport layer was changed from 0.61 μm to 0.52 μm (Example 7), 0.40 μm (Example 8), and 0.26 μm (Example 9). Photoconductors were produced and evaluated in the same manner. The results are shown in Table 12.

(Example 10)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 12.
5 parts of an electron transport material (A101), 2.3 parts of an amine compound (C1-3), 3.3 parts of a resin (D1), 0.1 part of dodecylbenzenesulfonic acid as a catalyst, 100 parts of dimethylacetamide and 100 parts of methyl ethyl ketone Part of the mixed solvent was dissolved to prepare an electron transport layer coating solution. This electron transport layer coating solution is dip-coated on the conductive layer, and the resulting coating film is heated at 160 ° C. for 40 minutes to be cured, whereby an electron transport layer that is a cured film having a thickness of 0.51 μm is obtained. Formed.

(Examples 11 and 12)
An electrophotographic photosensitive member was produced in the same manner as in Example 10 except that the thickness of the electron transport layer was changed from 0.51 μm to 0.45 μm (Example 11) and 0.34 μm (Example 12). evaluated. The results are shown in Table 12.

(Example 13)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 12.

(Electron transport layer)
5 parts of an electron transport material (A101), 1.75 parts of an amine compound (C1-3), 2 parts of a resin (D1), 0.1 part of dodecylbenzenesulfonic acid as a catalyst, 100 parts of dimethylacetamide and 100 parts of methyl ethyl ketone. It melt | dissolved in the mixed solvent and prepared the coating liquid for electron carrying layers. This electron transport layer coating solution is applied onto the conductive layer by dip coating, and the resulting coating film is heated at 160 ° C. for 40 minutes to polymerize the electron transport layer, which is a cured film having a thickness of 0.70 μm. Formed.

(Examples 14 to 16)
Electrons were transferred in the same manner as in Example 13 except that the thickness of the electron transport layer was changed from 0.70 μm to 0.58 μm (Example 14), 0.50 μm (Example 15), and 0.35 μm (Example 16). Photoconductors were produced and evaluated in the same manner. The results are shown in Table 12.

(Examples 17 to 32)
An electrophotographic photosensitive member was produced in the same manner as in Example 9 except that the electron transport material (A101) in Example 9 was changed as shown in Table 12, and evaluated in the same manner. The results are shown in Table 12.

(Examples 33 to 47)
An electrophotographic photosensitive member was produced in the same manner as in Example 16 except that the electron transport material of Example 16 was changed from (A101) as shown in Tables 12 and 13, and evaluated in the same manner. The results are shown in Tables 12 and 13.

(Examples 48 to 53)
An electrophotographic photosensitive member was produced in the same manner as in Example 8 except that the thickness of the crosslinking agent and the electron transport layer in Example 8 was changed as shown in Table 13, and evaluated in the same manner. The results are shown in Table 13.

(Examples 54 and 55)
An electrophotographic photosensitive member was produced in the same manner as in Example 16 except that the crosslinking agent in Example 16 was changed as shown in Table 13, and evaluated in the same manner. The results are shown in Table 13.

(Example 56)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 13.
4 parts of an electron transport material (A101), 4 parts of an amine compound (C1-9), 1.5 parts of a resin (D1), 0.2 part of dodecylbenzenesulfonic acid as a catalyst, 100 parts of dimethylacetamide and 100 parts of methyl ethyl ketone. It melt | dissolved in the mixed solvent and prepared the coating liquid for electron carrying layers. The electron transport layer coating solution is dip-coated on the conductive layer, and the resulting coating film is heated at 160 ° C. for 40 minutes to polymerize the electron transport layer, which is a cured film having a thickness of 0.35 μm. Formed.

(Examples 57 and 58)
An electrophotographic photosensitive member was produced in the same manner as in Example 56 except that the crosslinking agent in Example 56 was changed as shown in Table 13, and evaluated in the same manner. The results are shown in Table 13.

(Examples 59-62)
An electrophotographic photosensitive member was produced in the same manner as in Example 9 except that the resin of Example 9 was changed as shown in Table 13, and evaluated in the same manner. The results are shown in Table 13.

(Example 63)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 13.
6 parts of electron transport material (A124), 2.1 parts of amine compound (C1-3), 1.2 parts of resin (D21), 0.1 part of dodecylbenzenesulfonic acid as a catalyst, 100 parts of dimethylacetamide and 100 of methyl ethyl ketone Part of the mixed solvent was dissolved to prepare an electron transport layer coating solution. This electron transport layer coating solution is dip coated on the conductive layer, and the resulting coating film is heated for 40 minutes at 160 ° C. to polymerize the electron transport layer, which is a cured film having a thickness of 0.80 μm. Formed.

(Examples 64 and 65)
An electrophotographic photosensitive member was produced in the same manner as in Example 63 except that the electron transport material of Example 63 was changed from (A124) as shown in Table 13, and evaluated in the same manner. The results are shown in Table 13.

Example 66
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 13.
6 parts of electron transport material (A125), 2.1 parts of amine compound (C1-3), 0.5 part of resin (D21), 0.1 part of dodecylbenzenesulfonic acid as a catalyst, 100 parts of dimethylacetamide and 100 of methyl ethyl ketone Part of the mixed solvent was dissolved to prepare an electron transport layer coating solution. This electron transport layer coating solution is applied onto the conductive layer by dip coating, and the resulting coating film is heated at 160 ° C. for 40 minutes to polymerize the electron transport layer, which is a cured film having a thickness of 2.10 μm. Formed.

(Example 67)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 13.
6.5 parts of electron transport material (A125), 2.1 parts of amine compound (C1-3), 0.4 part of resin (D21), 0.1 part of dodecylbenzenesulfonic acid as a catalyst, and 100 parts of dimethylacetamide It melt | dissolved in the mixed solvent of 100 parts of methyl ethyl ketone, and prepared the coating liquid for electron carrying layers. This electron transport layer coating solution is applied onto the conductive layer by dip coating, and the resulting coating film is heated at 160 ° C. for 40 minutes to polymerize the electron transport layer, which is a cured film having a thickness of 2.10 μm. Formed.

Example 68
An electrophotographic photosensitive member was produced in the same manner as in Example 66 except that the thickness of the electron transport layer was changed from 2.10 μm to 1.55 μm, and evaluated in the same manner. The results are shown in Table 13.

(Example 69)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 13.
3.6 parts of an electron transport material (A404), 7.0 parts of an isocyanate compound (B1: protecting group (H1) = 5.1: 2.2 (mass ratio)), 1.3 parts of a resin (D11), as a catalyst Was dissolved in a mixed solvent of 100 parts of dimethylacetamide and 100 parts of methyl ethyl ketone to prepare a coating solution for an electron transport layer. The electron transport layer coating solution is dip-coated on the conductive layer, and the resulting coating film is heated at 160 ° C. for 40 minutes to polymerize the electron transport layer, which is a cured film having a thickness of 0.53 μm. Formed.

(Examples 70 to 77)
An electrophotographic photosensitive member was formed in the same manner as in Example 69 except that the types of the electron transporting material, the crosslinking agent, and the resin in Example 69 were changed as shown in Table 13, and evaluated in the same manner. The results are shown in Table 13.

(Examples 78 and 79)
The electrophotographic photosensitive material of Example 69 was changed in the same manner as in Example 69 except that the types of the electron transport material, the crosslinking agent, and the resin were changed as shown in Table 13 and the film thickness of the electron transport layer was changed to 1.20 μm. A body was prepared and evaluated in the same manner. The results are shown in Table 13.

(Example 80)
An electrophotographic photosensitive member was produced in the same manner as in Example 63 except that the thickness of the electrotransport layer was changed from 0.80 μm to 3.30 μm, and evaluated in the same manner. The results are shown in Table 13.

(Example 81)
An electrophotographic photosensitive member was produced in the same manner as in Example 64 except that the thickness of the electrotransport layer was changed from 0.80 μm to 3.80 μm, and evaluated in the same manner. The results are shown in Table 13.

(Example 82)
An electrophotographic photosensitive member was produced in the same manner as in Example 66 except that the thickness of the electron transport layer was changed from 2.10 μm to 4.50 μm, and evaluated in the same manner. The results are shown in Table 13.

(Examples 83-85)
An electrophotographic photosensitive member was formed in the same manner as in Example 69 except that the types of the electron transporting material, the crosslinking agent, and the resin in Example 69 were changed as shown in Table 13, and evaluated in the same manner. The results are shown in Table 13.

(Example 86)
In Example 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the adjustment of the conductive layer coating solution, the undercoat layer coating solution, and the hole transport layer coating solution was changed as follows. In the same way, we evaluated positive memory. The results are shown in Table 14.

The preparation of the coating solution for the conductive layer was changed as follows. 214 parts of titanium oxide (TiO ₂ ) particles coated with oxygen-deficient tin oxide (SnO ₂ ) as metal oxide particles, 132 parts of phenol resin (trade name: Priorofen J-325) as a binder resin And 98 parts of 1-methoxy-2-propanol as a solvent was put into a sand mill using 450 parts of glass beads having a diameter of 0.8 mm. Next, a dispersion treatment was performed under the conditions of a rotation speed: 2000 rpm, a dispersion treatment time: 4.5 hours, and a cooling water set temperature: 18 ° C. to obtain a dispersion.
Glass beads were removed from this dispersion with a mesh (aperture: 150 μm).
Silicone resin particles as a surface-roughening agent were added to the dispersion so as to be 10% by mass with respect to the total mass of the metal oxide particles and the binder resin in the dispersion after removing the glass beads. As the silicone resin particles, those having a trade name: Tospearl 120, manufactured by Momentive Performance Materials Co., Ltd., having an average particle diameter of 2 μm were used. Moreover, the conductive layer is prepared by adding silicone oil as a leveling agent to the dispersion and stirring so that the total mass of the metal oxide particles and the binder resin in the dispersion is 0.01% by mass. A coating solution was prepared. As the silicone oil, a product name: SH28PA, manufactured by Toray Dow Corning Co., Ltd. was used. The conductive layer coating solution was dip-coated on a support, and the resulting coating film was dried and thermally cured at 150 ° C. for 30 minutes to form a conductive layer having a thickness of 30 μm.

Next, the preparation of the coating solution for the undercoat layer was changed as follows. 6.2 parts of compound (A168), 7 parts of crosslinking agent (B1, protecting group (H5) = 5.1: 2.9 (mass ratio)), 1.1 parts of resin (B25), dioctyltin lauri as a catalyst 0.05 parts of the rate was dissolved in a mixed solvent of 100 parts of dimethylacetamide and 100 parts of methyl ethyl ketone to prepare an undercoat layer coating solution.
The undercoat layer coating solution is dip-coated on the conductive layer, and the resulting coating film is heated at 160 ° C. for 40 minutes to be cured (polymerized), thereby forming a cured film having a thickness of 0.52 μm. A pulling layer was formed.

Next, the preparation of the hole transport layer coating solution was changed as follows. 9 parts of a hole transport material having a structure represented by the above formula (9), 1 part of a hole transport material having a structure represented by the following formula (18), a repeating structure represented by the following formula (24), 26) and 3 parts of a polyester resin F (weight average molecular weight 90,000) having a repeating structure represented by the following formula (25) in a ratio of 7: 3 and the above formula (10-1). 7 parts of a polyester resin I (weight average molecular weight 120,000) containing a repeating structure represented by the above formula (10-2) in a ratio of 5: 5, 30 parts of dimethoxymethane and 50 parts of orthoxylene. A coating liquid for a hole transport layer was prepared by dissolving in a mixed solvent. In addition, the content of the repeating structural unit represented by the following formula (24) in the polyester resin F is 10% by mass, and the content of the repeating structural unit represented by the following formulas (25) and (26) is 90% by mass. %Met.

  This hole transport layer coating solution was dip-coated on the charge generation layer and dried at 120 ° C. for 1 hour to form a hole transport layer having a thickness of 16 μm. It was confirmed that the formed hole transport layer contained a domain structure containing polyester resin F in a matrix containing a charge transport material and polyester resin I.

(Example 87)
In Example 86, an electrophotographic photosensitive member was produced in the same manner as in Example 86 except that the preparation of the coating solution for the hole transport layer was changed as follows, and the positive memory was similarly evaluated. The results are shown in Table 14.

The preparation of the coating solution for the hole transport layer was changed as follows. 9 parts of a hole transport material having a structure represented by the above formula (9), 1 part of a hole transport material having a structure represented by the above formula (18), and a polycarbonate resin having a repeating structure represented by the following formula (29) 10 parts of J (weight average molecular weight 70,000), a repeating structure represented by the following formula (29), a repeating structure represented by the following formula (30), and at least one of the terminals represented by the following formula (31) A coating solution for a hole transport layer was prepared by dissolving 0.3 part of polycarbonate resin K (weight average molecular weight 40,000) having the structure shown in 30 parts of dimethoxymethane and 50 parts of orthoxylene. The total mass of the structures represented by the following formulas (30) and (31) in the polycarbonate resin K was 30% by mass. This hole transport layer coating solution was dip-coated on the charge generation layer and dried at 120 ° C. for 1 hour to form a hole transport layer having a thickness of 16 μm.

(Example 88)
In the preparation of the hole transport layer coating solution of Example 87, an electrophotographic photosensitive member was prepared in the same manner as in Example 87 except that 10 parts of polyester resin I (weight average molecular weight 120,000) was used instead of 10 parts of polycarbonate resin J. And evaluated the positive memory in the same way. The results are shown in Table 14.

(Examples 89 to 91)
In Examples 86 to 88, an electrophotographic photosensitive member was produced in the same manner as in Examples 86 to 88 except that the preparation of the coating liquid for the conductive layer was changed as follows, and the positive memory was similarly evaluated. The results are shown in Table 14.

The preparation of the coating solution for the conductive layer was changed as follows. 207 parts of titanium oxide (TiO ₂ ) particles coated with tin oxide (SnO ₂ ) doped with phosphorus (P) as metal oxide particles, phenol resin as a binder resin (trade name: Pryofen J -325) 144 parts and 98 parts of 1-methoxy-2-propanol as a solvent are put in a sand mill using 450 parts of glass beads having a diameter of 0.8 mm, the rotation speed is 2000 rpm, and the dispersion treatment time is 4.5. Dispersion treatment was performed under the conditions of time and cooling water set temperature: 18 ° C. to obtain a dispersion.
Glass beads were removed from this dispersion with a mesh (aperture: 150 μm).

  Silicone resin particles as a surface roughening agent (trade name: Tospearl 120) so as to be 15% by mass with respect to the total mass of the metal oxide particles and the binder resin in the dispersion after removing the glass beads Was added to the dispersion. Further, a silicone oil (trade name: SH28PA) as a leveling agent is added to the dispersion so as to be 0.01% by mass with respect to the total mass of the metal oxide particles and the binder resin in the dispersion, followed by stirring. By doing this, the coating liquid for conductive layers was prepared. The conductive layer coating solution was dip-coated on a support, and the resulting coating film was dried and thermally cured at 150 ° C. for 30 minutes to form a conductive layer having a thickness of 30 μm.

(Examples 92 and 93)
In Example 86, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the type and content of the electron transporting material were changed as shown in Table 14, and the positive memory was similarly evaluated. The results are shown in Table 14.

(Comparative Example 1)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 15.
4.0 parts of an electron transport material (A225), 3 parts of hexamethylene diisocyanate, and 4 parts of resin (D1) were dissolved in a mixed solvent of 100 parts of dimethylacetamide and 100 parts of methyl ethyl ketone to prepare a coating solution for an electron transport layer. This electron transport layer coating solution was dip-coated on the conductive layer, and the resulting coating film was heated at 160 ° C. for 40 minutes for polymerization to form an electron transport layer having a thickness of 1.0 μm.

(Comparative Example 2)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 15.
5 parts of electron transport material (A124), 2.5 parts of 2,4-toluene diisocyanate, 2.5 parts of poly (p-hydroxystyrene) (trade name: Marcalinker, Maruzen Petrochemical Co., Ltd.), 100 parts of dimethylacetamide And 100 parts of methyl ethyl ketone were dissolved in a mixed solvent to prepare a coating solution for an electron transport layer. This electron transport layer coating solution was dip-coated on the conductive layer, and the resulting coating film was heated at 160 ° C. for 40 minutes for polymerization to form an electron transport layer having a thickness of 0.4 μm.

(Comparative Example 3)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 15.
7 parts of an electron transport material (A124), 2.0 parts of 2,4-toluene diisocyanate, and 1 part of “Marcalinker” are dissolved in a mixed solvent of 100 parts of dimethylacetamide and 100 parts of methyl ethyl ketone, and an electron transport layer coating solution is prepared. Prepared. This electron transport layer coating solution was dip-coated on the conductive layer, and the resulting coating film was heated at 160 ° C. for 40 minutes for polymerization to form an electron transport layer having a thickness of 0.4 μm.

(Comparative Example 4)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 16.
5 parts of an electron transport material (A922), 13.5 parts of an isocyanate compound (Sumijour 3173, manufactured by Sumitomo Bayern Urethane Co., Ltd.), 10 parts of butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.), dioctyltin as a catalyst 0.005 part of laurate was dissolved in 120 parts of methyl ethyl ketone to prepare an electron transport layer coating solution. This electron transport layer coating solution was dip-coated on the conductive layer, and the resulting coating film was heated at 170 ° C. for 40 minutes for polymerization to form an electron transport layer having a thickness of 1.0 μm.

(Comparative Example 5)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 16.
An electron transport layer coating solution was prepared by dissolving 5 parts of an electron transport material (A101) and 2.4 parts of a melamine resin (Uban 20HS: manufactured by Mitsui Chemicals) in a mixed solvent of 50 parts of tetrahydrofuran and 50 parts of methoxypropanol. This electron transport layer coating solution was dip-coated on the conductive layer, and the resulting coating film was heated at 150 ° C. for 60 minutes for polymerization to form an electron transport layer having a thickness of 1.00 μm.

(Comparative Example 6)
An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Comparative Example 5 except that the thickness of the electron transport layer was changed from 1.00 μm to 0.50 μm. The results are shown in Table 16.

(Comparative Example 7)
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 5 except that the melamine resin of the electron transport layer was changed to a phenol resin (Priofen J325: manufactured by Dainippon Ink & Chemicals, Inc.), and evaluated in the same manner. The results are shown in Table 16.

(Comparative Example 8)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 16.
5 parts of an electron transporting material represented by the following formula (12), 5 parts of trimethylolpropane triacrylate (Kayarad TMPTA: manufactured by Nippon Kayaku Co., Ltd.), AIBN (2,2-azobisisobutyronitrile) 0.1 A part was dissolved in 190 parts of tetrahydrofuran to prepare an electron transport layer coating solution. This electron transport layer coating solution was applied onto the conductive layer by dip coating, and the resulting coating film was heated at 150 ° C. for 30 minutes for polymerization to form an electron transport layer having a thickness of 0.8 μm.

(Comparative Example 9)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 16.
5 parts of the electron transport material represented by the above formula (12) and 5 parts of the compound represented by the following formula (13) were dissolved in a mixed solvent of 60 parts of toluene to prepare an electron transport layer coating solution. This electron transport layer coating solution is dip-coated on the conductive layer, and the resulting coating film is irradiated with an electron beam under the conditions of an acceleration voltage of 150 kV and an irradiation dose of 10 Mrad to polymerize an electron having a film thickness of 1.0 μm. A transport layer was formed.

(Comparative Example 10)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 16.
An electron transport layer is formed using a block copolymer represented by the following formula described in Example 1 of JP-T-2009-505156, a blocked isocyanate compound, and a vinyl chloride-vinyl acetate copolymer, and is 0.32 μm. The electron transport layer was formed.

(Comparative Example 11)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 16.
5 parts of an electron transport material (A101) and 5 parts of a polycarbonate resin (Z200: manufactured by Mitsubishi Gas Chemical Co., Ltd.) were dissolved in a mixed solvent of 50 parts of dimethylacetamide and 50 parts of chlorobenzene to prepare an electron transport layer coating solution. . This electron transport layer coating solution was dip-coated on the conductive layer, and the resulting coating film was heated at 120 ° C. for 30 minutes for polymerization to form an electron transport layer having a thickness of 1.00 μm.

(Comparative Example 12)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 16.
To a solution obtained by dissolving 5 parts of the resin (D1) in a mixed solvent of 200 parts of methyl ethyl ketone, 5 parts by weight of an electron transport material (pigment) represented by the following structural formula (15) is added, and dispersion treatment is performed in a sand mill for 3 hours. An electron transport layer coating solution was prepared. This coating solution for electron transport layer was dip-coated on the conductive layer, and the obtained coating film was heated at 100 ° C. for 10 minutes to form an electron transport layer having a thickness of 1.5 μm.

(Comparative Example 13)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 16.
An electron transport layer was formed using a zinc oxide pigment surface-treated with a silane coupling agent, alizarin (A922), blocked isocyanate and a butyral resin (configuration of Example 1 of JP-A-2006-030698), and 25 μm An electron transport layer was formed.

(Comparative Example 14)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 16.
A mixed solvent of 30 parts of N-methyl-2-pyrrolidone and 60 parts of cyclohexanone in 10 parts of a mixture of the compound having the structure represented by the following formula (11-1) and the compound having the structure represented by (11-2) To prepare an electron transport layer coating solution. A film having a structure represented by the following formula (11-3) by dip-coating the coating solution for the electron transport layer on the conductive layer, and heating and polymerizing the obtained coating film at 150 ° C. for 30 minutes. An electron transport layer having a thickness of 0.20 μm was formed.

(Comparative Example 15)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 16.
10 parts of the electron transport material represented by the above formula (12) were dissolved in a mixed solvent of 60 parts of toluene to prepare an electron transport layer coating solution. This electron transport layer coating solution is dip-coated on the conductive layer, and the resulting coating film is irradiated with an electron beam under the conditions of an acceleration voltage of 150 kV and an irradiation dose of 10 Mrad to polymerize an electron having a film thickness of 1.0 μm. A transport layer was formed.

(Comparative Example 16)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 16.
An electron transport layer was formed using the copolymer particles containing the electron transport material described in Example 1 of Japanese Patent No. 4594444, and an electron transport layer having a thickness of 1.00 μm was formed.

(Comparative Example 17)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the electron transport layer was formed as follows and evaluated in the same manner. The results are shown in Table 16.
An electron transport layer is formed using a coating liquid for an electron transport layer in which a polymer of an electron transport material described in Example 1 of JP-A-2004-093801 is dissolved in a solvent, and the film thickness is 2.00 μm. An electron transport layer was formed.

  Contains a cured product obtained by polymerizing a composition containing an electron transport material having a polymerizable functional group, a thermoplastic resin having a polymerizable functional group, and a cross-linking agent by comparison between Examples and Comparative Examples 1 to 9. Even if it does, the effect of this application may not be acquired. That is, the electron transport layer that does not satisfy the formulas (1) to (3) of the present invention of Comparative Examples 1 to 9 reduces the plus memory compared to the case where the range of the formulas (1) to (3) of the examples is satisfied. It can be seen that the effect and suppression of potential fluctuation may not be sufficiently obtained. Moreover, in Comparative Examples 5-9, since there was no resin, as a result of many bonds between the crosslinking agents proceeding, aggregation of the electron transport material was caused, and the results of not satisfying the formulas (1) to (3) were obtained. it is conceivable that. Further, it is understood from the comparison between the example and the comparative example 10 that the effect of reducing the positive memory may not be sufficiently obtained even in the electron transport layer described in JP-T-2009-505156. Since this is a polymer having a large molecular weight of the electron transport material, aggregation of components occurs in the electron transport layer, which does not satisfy the formulas (1) to (3), and it is considered that positive memory is likely to occur.

  Comparison between Examples and Comparative Examples 10 to 13 shows that when a large amount of an electron transport material having no polymerizable functional group or a metal oxide is contained, the formulas (1) to (3) are not satisfied and a plus memory is obtained. It has been shown that the reduction effect and the suppression of potential fluctuation cannot be sufficiently obtained. In an electron transport layer containing an electron transport material having no polymerizable functional group, the electron transport material is eluted into the photosensitive layer, and the concentration of the electron transport material in the electron transport layer at the interface of the charge generation layer is greatly reduced. It is thought that there is.

  According to Comparative Examples 14 to 17, when the electron transport layer comprises a film made of only the electron transport material, the range of the formulas (1) to (3) is not satisfied, and the plus memory is not sufficiently reduced. I understand that there is.

DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 Axis 3 Charging means 4 Exposure light 5 Developing means 6 Transfer means 7 Cleaning means 8 Fixing means 9 Process cartridge 10 Guide means P Transfer material 101 Support body 102 Electron transport layer 103 Photosensitive layer 104 Charge generation layer 105 Positive Hole transport layer

Claims (12)

An electrophotographic photosensitive member having a support, an electron transport layer formed on the support, and a photosensitive layer formed on the electron transport layer,
The electron transport layer is a cured film containing carbon atoms, nitrogen atoms and oxygen atoms,
The electrophotographic photoreceptor, wherein the electron transport layer satisfies the following formulas (1) to (3).
σ (C) ≦ 1.5 (1)
σ (N) ≦ 1.5 (2)
σ (O) ≦ 1.5 (3)
(In the formulas (1) to (3),
σ (C) is 10 points obtained when the ratio (atoms%) of the carbon atoms to all atoms excluding hydrogen atoms in the electron transport layer at 10 points was analyzed by X-ray photoelectron spectroscopy (ESCA). Indicates the standard deviation of the values.
σ (N) is 10 points obtained when the ratio (atoms%) of the nitrogen atoms to all atoms excluding hydrogen atoms in the electron transport layer at 10 points was analyzed by X-ray photoelectron spectroscopy (ESCA). Indicates the standard deviation of the values.
σ (O) is 10 points obtained when the ratio (atoms%) of the oxygen atoms to all atoms excluding hydrogen atoms in the electron transport layer at 10 points is analyzed by X-ray photoelectron spectroscopy (ESCA). Indicates the standard deviation of the values.
The ten points consist of the upper and lower points of the electron transport layer and eight points that divide the thickness of the electron transport layer into nine equal parts in the depth direction. ) The electrophotographic photosensitive member according to claim 1, wherein the standard deviations σ (C), σ (N), and σ (O) satisfy the following formulas (4) to (6).
σ (C) ≦ 1.0 (4)
σ (N) ≦ 1.0 (5)
σ (O) ≦ 1.0 (6)   The total of the carbon atom ratio, the nitrogen atom ratio, and the oxygen atom ratio in the electron transport layer is 90% or more and 100% or less (excluding hydrogen atoms having no measurement sensitivity in ESCA). 3. The electrophotographic photosensitive member according to 1 or 2.   The said electron carrying layer contains the hardened | cured material of the composition containing the electron carrying substance which has a polymeric functional group, the thermoplastic resin which has a polymeric functional group, and a crosslinking agent in any one of Claim 1 to 3. The electrophotographic photosensitive member described.   The electrophotographic photosensitive member according to claim 4, wherein the thermoplastic resin has a weight average molecular weight of 5,000 to 400,000.   The electrophotographic photosensitive member according to claim 5, wherein the thermoplastic resin has a weight average molecular weight of 5,000 to 300,000.   7. The polymerizable functional group of the electron transport material is at least one selected from the group consisting of a hydroxy group, a thiol group, an amino group, a methoxy group, and a carboxyl group. Electrophotographic photoreceptor.   The electrophotographic photosensitive member according to claim 4, wherein the electron transport material has a molecular weight of 1000 or less. The crosslinking agent is an isocyanate group, a blocked isocyanate group or a group represented by _-CH 2 -OR ^{1 (R 1} is a hydrogen atom or an alkyl group) of claims 4 to 8 which is a compound having 3 to 6, The electrophotographic photosensitive member according to any one of the above.   The electrophotographic photosensitive member according to claim 4, wherein the cross-linking agent has a molecular weight of 1000 or less.   An electrophotographic photosensitive member according to any one of claims 1 to 10 and at least one means selected from the group consisting of a charging means, a developing means, a transfer means, and a cleaning means are integrally supported, and electrophotographic A process cartridge that is detachable from the device.   An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1, and a charging unit, an exposing unit, a developing unit, and a transferring unit.

Images