JP6354352B2 - Electrophotographic photosensitive member, electrophotographic image forming apparatus and process cartridge - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member, an electrophotographic image forming apparatus, and a process cartridge. More specifically, an electrophotographic photoreceptor capable of forming a high-quality electrophotographic image that is excellent in abrasion resistance, hardly peels off, and does not generate an image memory under a high-temperature and high-humidity environment, and the electrophotographic photoreceptor are used. The present invention relates to an electrophotographic image forming apparatus and a process cartridge used in the electrophotographic image forming apparatus.

  2. Description of the Related Art In recent years, electrophotographic image forming apparatuses have been demanded to reduce the size of the apparatus and make it maintenance-free as the print output speed increases. Along with these demands, there is an increasing demand for reduction in the diameter (miniaturization) and high durability of the drum-like photoreceptor in the electrophotographic photoreceptor used in the electrophotographic image forming apparatus. The photosensitive layer of an organic photoreceptor (hereinafter also referred to as “photoreceptor”) that is commonly used as an electrophotographic photoreceptor is composed of a charge transport material, a binder resin, and the like, and is easily worn by a mechanical load. This is a cause of reducing the life of the photoreceptor.

  In order to increase the durability of the photoreceptor, it is necessary to improve the abrasion resistance of the photoreceptor, and a technique for providing a surface protective layer on the surface of the photosensitive layer has been studied. As a surface protective layer excellent in wear resistance, a technique of adding a curable binder resin and metal oxide fine particles to the surface protective layer has been proposed.

In addition, for the purpose of preventing a decrease in electrical characteristics due to the provision of a surface protective layer, a technique has been proposed in which a charge transport material is added to the surface protective layer to impart charge transport performance.
From these two technologies, for the purpose of improving wear resistance, image memory prevention properties, etc., a technology has been proposed in which the surface protective layer contains a charge transport material or metal oxide fine particles (for example, Patent Document 1). reference.). However, these proposed surface protective layers have a problem in that the compatibility between the charge transport material and the metal oxide fine particles is poor, and film peeling tends to occur.

Furthermore, a technique has been proposed in which metal oxide fine particles whose surface is modified with a compound having a hole transporting group are added to the surface protective layer in order to improve wear resistance (see, for example, Patent Document 2). In this technology, metal oxide fine particles surface-modified with an alkoxysilane compound having a hole transporting group are added to the surface protective layer, so that the metal oxide fine particles are uniformly dispersed in the surface protective layer. The wear resistance can be improved by the filler effect by the fine particles and the curable binder resin.
However, this technique has a problem that an image memory is generated under high temperature and high humidity conditions.

JP2013-61625A JP 2010-134071 A

  The present invention has been made in view of the above-mentioned problems and circumstances, and a solution to the problem is high-quality electronic that is excellent in abrasion resistance, hardly peels off, and does not generate image memory in a high-temperature and high-humidity environment. An object of the present invention is to provide an electrophotographic photoreceptor capable of forming a photographic image. Another object of the present invention is to provide an electrophotographic image forming apparatus using the electrophotographic photosensitive member of the present invention and a process cartridge used in the electrophotographic image forming apparatus.

In order to solve the above problems, the present inventor, in the process of studying the cause of the above problems, the surface protective layer is a surface-modified metal with a binder resin, a charge transport agent, and a hole transporting compound having an acidic group The inventors have found that the above problems can be solved by containing oxide fine particles, and have reached the present invention.
That is, the said subject which concerns on this invention is solved by the following means.

（一般式（１）中、Ａは正孔輸送性基を表す。Ｑ_１は酸性基を表す。Ｒ_１は置換若しくは無置換の、アルキレン基、アルケニレン基、アルキニレン基又はアリーレン基を表す。ｋは、１以上の正の整数を表す。ｋが２以上の整数を表す場合、Ｒ_１及びＱ_１は、それぞれ同一であっても異なっていてもよい。） 1. An electrophotographic photosensitive member in which a photosensitive layer and a surface protective layer are sequentially laminated on a conductive support, wherein the surface protective layer has a structure represented by a binder resin, a charge transport agent, and the following general formula (1) A resin obtained by polymerizing a crosslinkable polymerizable compound having an acryloyl group or a methacryloyl group, a polycarbonate resin, or a metal oxide fine particle surface-modified with a hole transporting compound having An electrophotographic photoreceptor containing any of polyarylate resins .

(In general formula (1), A represents a hole transporting group. Q ₁ represents an acidic group. R ₁ represents a substituted or unsubstituted alkylene group, alkenylene group, alkynylene group or arylene group. K , when .k representing a positive integer of 1 or more represents an integer of 2 or more, R ₁ and Q ₁ may have each be the same or different.)

（一般式（２）中、Ａｒ_１は、置換又は無置換のアリール基を表す。Ａｒ_２、Ａｒ_３、Ａｒ_４及びＡｒ_５は、同じでも異なっていてもよく、それぞれ置換又は無置換のアリーレン基を表す。Ｒ_２及びＲ_３は、同じでも異なっていてもよく、それぞれ置換若しくは無置換の、アルキレン基、アルケニレン、アルキニレン基又はアリーレン基を表す。Ｑ_２及びＱ_３は、同じでも異なっていてもよく、それぞれ酸性基を表す。ｍ、ｎ、ｐ及びｑは、０又は１を表す。ｐが０のとき、Ａｒ_３は置換又は無置換のアリール基を表す。） 2. 2. The electrophotographic photosensitive material according to item 1, wherein the hole transporting compound having a structure represented by the general formula (1) is a compound having a structure represented by the following general formula (2): body.

(In General Formula (2), Ar ₁ represents a substituted or unsubstituted aryl group. Ar ₂ , Ar ₃ , Ar _4, and Ar ₅ may be the same or different, and each is a substituted or unsubstituted arylene. R ₂ and R ₃ may be the same or different and each represents a substituted or unsubstituted alkylene group, alkenylene, alkynylene group, or arylene group, and Q ₂ and Q ₃ are the same or different. And m, n, p and q each represents 0 or 1. When p is 0, Ar ₃ represents a substituted or unsubstituted aryl group.

  3. 3. The electrophotographic photosensitive member according to item 1 or 2, wherein the charge transfer agent has a molecular weight in the range of 250 to 800.

  4). 4. The electrophotographic photosensitive material according to any one of items 1 to 3, wherein the metal oxide fine particles are any of tin oxide fine particles, titanium oxide fine particles, zinc oxide fine particles, and alumina fine particles. body.

5 . An electrophotographic image forming apparatus having at least a charging unit for charging an electrophotographic photosensitive member, an exposing unit, a developing unit, and a transferring unit, wherein the electrophotographic photosensitive member is any one of items 1 to 4. An electrophotographic image forming apparatus, which is the electrophotographic photosensitive member according to the above.

6 . A process cartridge for use in the electrophotographic image forming apparatus according to Item 5 , wherein the process cartridge includes at least the electrophotographic photosensitive member according to any one of Items 1 to 4 and a charging unit. A process cartridge having at least one of an exposure unit and a development unit as a unit and configured to be able to be taken in and out of the electrophotographic image forming apparatus.

  By the above means of the present invention, it is possible to provide an electrophotographic photosensitive member that can form a high-quality electrophotographic image that is excellent in abrasion resistance, hardly peels off, and does not generate an image memory in a high-temperature and high-humidity environment. . In addition, an electrophotographic image forming apparatus using the electrophotographic photosensitive member of the present invention and a process cartridge used in the electrophotographic image forming apparatus can be provided.

  The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.

The surface protective layer according to the present invention comprises a charge transporting agent and a hole transporting compound having a structure represented by the general formula (1) (hereinafter referred to as “a hole transporting compound having an acidic group” or simply “holes”). The hole transporting compound is uniformly dispersed in the surface protective layer by surface-modifying the metal oxide fine particles with “transporting compound”. For this reason, the hole movement in the surface protective layer is not inhibited, and the electrical characteristics as an electrophotographic photosensitive member such as charging characteristics and sensitivity characteristics are not impaired. Further, since the metal oxide fine particles are dispersed in the surface protective layer, a strong film can be formed by the filler effect, so that the wear resistance of the surface protective layer is improved. Estimated to improve durability.
In addition, if an organic compound having a chemical structure similar to the hole transporting compound, which is the surface modification part of the metal oxide fine particles, is used as the charge transporting agent, the affinity can be maintained at that part, and the film is peeled off. Estimated to be effective in prevention.

  On the other hand, silane coupling agents such as alkoxysilane compounds (also referred to as “surface treatment agents” or “surface modifiers”) hydrolyze alkoxy groups to form silanol groups, which are converted into metal oxides. After transferring to the surface through a hydrogen bond with a hydroxy group on the surface of the fine particle, a strong covalent bond is formed with the surface of the metal oxide fine particle through a dehydration condensation reaction. In parallel, silanol groups are condensed to form a siloxane bond. At this time, some alkoxysilane compounds do not react with the hydroxy groups on the surface of the metal oxide fine particles, and siloxane bonds are formed between the alkoxysilane compounds. That is, a self-condensation reaction occurs. For this reason, the hole transporting compound is not adsorbed on the surface of the metal oxide fine particles, so that sufficient hole transport ability is not obtained, and image memory is generated when the metal oxide fine particles are incorporated into the surface protective layer. Resulting in.

Here, it is known that an acidic group such as a carboxy group forms an ionic bond with a hydroxy group on the surface of a metal oxide fine particle. Therefore, in the hole transporting compound according to the present invention, the acidic group forms an ionic bond with the hydroxy group on the surface of the metal oxide fine particles. Since the metal oxide fine particles to which the hole transporting compound is bonded through this ionic bond are uniformly dispersed in the surface protective layer, the hole protective performance of the surface protective layer is not impaired and a strong film is formed. Thus, image blur due to discharge products such as ozone and nitrogen oxides can be prevented. In addition, since the hole transporting compound according to the present invention does not have a self-condensable substituent such as an alkoxysilane compound, it does not undergo a self-condensation reaction. As a result, it is considered that the occurrence of image memory can be prevented.
Further, it is preferable that the metal oxide fine particles are contained in the surface protective layer because an effect of increasing the film strength of the surface protective layer can be obtained.

Schematic diagram showing an example of the layer structure of the photoreceptor 1 is a cross-sectional configuration diagram of a full-color electrophotographic image forming apparatus showing an example of an embodiment of the present invention.

The photoreceptor of the present invention is an electrophotographic photoreceptor in which a photosensitive layer and a surface protective layer are sequentially laminated on a conductive support, and the surface protective layer includes a binder resin, a charge transport agent, and the general formula ( 1) obtained by polymerizing a crosslinkable polymerizable compound having an acryloyl group or a methacryloyl group, the metal oxide fine particles surface-modified with a hole transporting compound having a structure represented by 1) Any of the obtained resin, polycarbonate resin, or polyarylate resin is contained. This feature is technical feature common to the invention according to each claim.

  As an embodiment of the present invention, a hole transporting compound having a structure represented by the general formula (1) has a structure represented by the general formula (2) from the viewpoint of manifesting the effects of the present invention. A compound is preferred because the hole transport performance of the surface protective layer is excellent.

  Further, the charge transport agent may be any one having charge transport performance, but if the molecular weight is in the range of 250 to 800, the surface hardness is maintained while preventing the charge transport function from being lowered. It's easy to do.

  Furthermore, it is preferable that the metal oxide fine particles are any of tin oxide fine particles, titanium oxide fine particles, zinc oxide fine particles, and alumina fine particles because the wear resistance of the surface protective layer is improved.

  Moreover, it is preferable that the binder resin contains a resin obtained by polymerizing a crosslinkable polymerizable compound because the wear resistance of the surface protective layer is improved.

  Furthermore, since the crosslinkable polymerizable compound is a polymerizable compound having an acryloyl group or a methacryloyl group, it can be easily polymerized by heat or light to form a highly wear-resistant surface protective layer. preferable.

  The photoreceptor of the present invention is suitable for an electrophotographic image forming apparatus having at least a charging means for charging the electrophotographic photoreceptor, an exposure means, a developing means, and a transfer means, and a process cartridge used in the electrophotographic image forming apparatus. Can be used.

  The constituent elements of the present invention and the modes and modes for carrying out the present invention will be described in detail below. In the present application, “to” is used in the sense of including the numerical values described before and after the lower limit value and the upper limit value.

≪Electrophotographic photoreceptor≫
The electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor in which a photosensitive layer and a surface protective layer are sequentially laminated on a conductive support, and the surface protective layer includes a binder resin, a charge transport agent, and the following general And metal oxide fine particles surface-modified with a hole transporting compound having a structure represented by the formula (1).

The photosensitive layer has both the function of generating light by absorbing light and the function of transporting charge. The layer structure of the photosensitive layer is a single layer structure containing a charge generating material and a charge transporting material. Alternatively, a stacked structure of a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material may be used.
Further, an intermediate layer may be provided between the conductive support and the photosensitive layer as necessary.
The layer structure of the photosensitive layer is not particularly limited, and examples of specific layer structures including the surface protective layer include the following (1) to (4).
(1) Layer structure in which a charge generation layer, a charge transport layer and a surface protective layer are sequentially laminated on a conductive support (2) A single layer containing a charge transport material and a charge generation material on a conductive support (3) Layer structure in which an intermediate layer, a charge generation layer, a charge transport layer, and a surface protective layer are sequentially stacked on a conductive support (4) Conductive support A layer structure in which an intermediate layer, a single-layer photosensitive layer containing a charge transporting substance and a charge generating substance, and a surface protective layer are sequentially laminated thereon. The photoreceptor of the present invention comprises any one of the above (1) to (4) layers. Of these, a layer structure prepared by sequentially providing an intermediate layer, a charge generation layer, a charge transport layer, and a surface protective layer on a conductive support is particularly preferable.

  FIG. 1 is a schematic diagram showing an example of the layer structure of the photoreceptor 10 of the present invention. In FIG. 1, 1 is a conductive support, 2 is a photosensitive layer, 3 is an intermediate layer, 4 is a charge generation layer, 5 is a charge transport layer, 6 is a surface protective layer, and 7 is a surface-modified metal oxide fine particle.

  Next, the structure of the surface protective layer, the conductive support, the intermediate layer, and the photosensitive layer (charge generation layer and charge transport layer) constituting the photoreceptor of the present invention will be described in order.

<Surface protective layer>
The surface protective layer according to the present invention contains a binder resin, a charge transport agent, and metal oxide fine particles whose surface is modified with a hole transporting compound having an acidic group. The materials constituting the surface protective layer will be described sequentially.

<Hole transporting compound>
The hole transporting compound according to the present invention has a structure represented by the following general formula (1).

In general formula (1), A represents a hole transporting group. Q ₁ represents an acidic group. R ₁ represents a substituted or unsubstituted alkylene group, alkenylene group, alkynylene group or arylene group. k represents a positive integer of 1 or more. When k represents an integer of 2 or more, R ₁ and Q ₁ may be the same or different from each other.

  The hole transporting group represented by A in the general formula (1) may be any group as long as it exhibits hole transporting properties, and the bonding site with R1 in the general formula (1) is a hydrogen atom. For example, an oxazole derivative, an oxadiazole derivative, an imidazole derivative, a triarylamine derivative such as triphenylamine, a styryltriphenylamine derivative, a distyryltriarylamine Derivatives, tristyryltriarylamine derivatives, styrylanthracene derivatives, styrylpyrazoline derivatives, phenylhydrazones, thiazole derivatives, thiadiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, thiophene derivatives And N- phenyl carbazole derivatives, and the like. Of these, triarylamine derivatives, styryltriarylamine derivatives, distyryltriarylamine derivatives, and the like are preferable.

Examples of the acidic group represented by Q ₁ include a carboxy group, a phosphonic acid group, a phosphinic acid group, and a sulfonic acid group.

R ₁ represents an alkylene group having 1 to 4 carbon atoms as an alkylene group, preferably a methylene group.
R ₁ represents an alkynylene group having 2 to 4 carbon atoms, preferably an ethynylene group, a vinylene group, a propynylene group, or a butynylene group. The arylene group is preferably a phenylene group or a naphthylene group. The substituent for the alkylene group, alkenylene group and alkynylene group represents an alkyl group having 1 to 4 carbon atoms, a chlorine atom, a bromine atom, a cyano group, or a substituted or unsubstituted amino group. The substituent for the arylene group represents an alkyl group having 1 to 4 carbon atoms, a chlorine atom, a bromine atom, or a substituted or unsubstituted amino group.

  Moreover, it is preferable that the hole transportable compound which has a structure represented by the said General formula (1) is a compound which has a structure represented by following General formula (2).

In General Formula (2), Ar ₁ represents a substituted or unsubstituted aryl group. Preferred aryl groups include phenyl and naphthyl groups. The substituent for the aryl group represents an alkyl group having 1 to 5 carbon atoms, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkenylene group, a chlorine atom, a bromine atom, or a substituted or unsubstituted amino group. . Examples of these substituents include alkyl groups having 1 to 5 carbon atoms and substituted and unsubstituted aryl groups.

Ar ₂ , Ar ₃ , Ar ₄ and Ar ₅ may be the same or different and each represents a substituted or unsubstituted arylene group. Preferred arylene groups include phenylene groups and naphthylene groups. The substituent for the arylene group represents an alkyl group having 1 to 5 carbon atoms, a chlorine atom, a bromine atom, or a substituted or unsubstituted amino group.

R ₂ and R ₃ may be the same or different and each represents a substituted or unsubstituted alkylene group, alkenylene, alkynylene group or arylene group.
Q ₂ and Q ₃ may be the same or different and each represents an acidic group. m, n, p, and q represent 0 or 1. When p is 0, Ar ₃ represents a substituted or unsubstituted aryl group. The substituent for Ar ₃ represents an alkyl group having 1 to 5 carbon atoms, a substituted or unsubstituted aryl group, or a substituted or unsubstituted alkenylene group. Examples of the substituent for the aryl group and alkenylene group include an alkyl group having 1 to 5 carbon atoms and substituted and unsubstituted aryl groups.

In the present invention, the acidic group represented by Q ₂ and Q ₃ is a carboxy group, a phosphonic acid group, a phosphinic acid group, or a sulfonic acid group, and the reactivity with the hydroxy group on the surface of the metal oxide fine particles is It is preferable because it is good.

  Specific examples of the hole transporting compound having the structure represented by the general formula (1) include the following compounds.

  The hole transporting compound having the structure represented by the general formula (1) can be synthesized by a known synthesis method. The synthesis method is illustrated below.

(Synthesis method)
(Synthesis Example (1): Synthesis Method of Compound Example [HTM-1])

  A 100 ml four-headed flask was equipped with a nitrogen inlet tube, a thermometer, a condenser tube and a dropping funnel, and 30.8 g (0.086 mol) of methyltriphenylphosphonium bromide (2) and 11.9 g of potassium tert-butoxy (0. 106 mol) and 15 ml of tetrahydrofuran (THF) are added and stirred at room temperature for 1 hour under a nitrogen stream.

  Thereafter, 20 g (0.073 mol) of 4- (diphenylamino) benzaldehyde (1) is dissolved in 40 ml of THF, and is slowly dropped into a dropping funnel. After completion of the dropping, the reaction was performed at room temperature for 2 hours. To this, 70 ml of water was added, extracted with ethyl acetate, and then washed with water until neutrality. The organic layer was dried and then concentrated, and purified by column chromatography. 16 g (yield: 89%) of 4- (diphenylamino) styrene (3) as pale yellow crystals was obtained.

  A 100 ml four-headed flask was equipped with a nitrogen inlet tube, a thermometer, a condenser tube and a dropping funnel, and 5 g (0.018 mol) of 4- (diphenylamino) styrene (3) was added to a 25 ml solution of N, N-dimethylacetamide (DMA). , 4-bromobenzaldehyde (4) 3.7 g (0.02 mol), palladium acetate 0.17 g (0.74 mmol), triphenylphosphine 0.77 g (2.95 mmol) and sodium carbonate 3.12 g (0.029 mol) And reacted for 12 hours at 110 ° C. under a nitrogen stream.

  After cooling to room temperature, 70 ml of water was added, extracted with ethyl acetate, and washed with water until neutral. The organic layer was dried and then concentrated and purified by column chromatography to obtain 5.9 g (89%) of yellow crystalline compound (5).

A 100 ml four-headed flask was equipped with a nitrogen inlet tube, a thermometer, a condenser tube and a dropping funnel, 5 g (0.013 mol) of compound (5), 1.7 g (0.016 mol) of malonic acid (6), and piperazine 0.8. 57 g (0.007 mol) and 33 ml of dimethylformamide (DMF) were added and reacted at 125 ° C. for 6 hours under a nitrogen stream. After cooling the reaction solution to 100 ° C. or lower, a 10% aqueous sulfuric acid solution was added dropwise over 30 minutes, followed by stirring for 30 minutes. This was extracted with ethyl acetate and washed with water until neutrality. The organic layer was dried and then concentrated and purified by column chromatography to obtain 5.5 g (98%) of [HTM-1] yellow crystals.
The above compound was confirmed to be [HTM-1] by nuclear magnetic resonance ( ¹ H-NMR).
¹ H-NMR (300 MHz, DMSO) δ ppm: 6.27 (d, 2H), 7.00 to 7.45 (m, 19H), 7.89 (d, 2H) 12.05 (d, 1H)

(Synthesis Example (2): Synthesis Method of Compound Example [HTM-39])

A 100 ml four-headed flask is equipped with a thermometer, a condenser and a dropping funnel, 5 g (0.011 mol) of the compound (7) is charged, and 9.0 g (0.055 mol) of triethyl phosphite is slowly added dropwise. The temperature was gradually raised and refluxed for 6 hours. After completion of the reaction, excess triethyl phosphite was distilled off under reduced pressure, and the obtained target product was purified by column chromatography to obtain 4.7 g (83%) of compound (8). This compound (8) was refluxed with 10 ml of concentrated hydrochloric acid for 24 hours to obtain 3.6 g (86%) of [HTM-39].
The above compound was confirmed to be [HTM-39] by nuclear magnetic resonance ( ¹ H-NMR).
¹ H-NMR (300 MHz, DMSO) δ ppm: 2.94 (d, 2H), 4.80 (s, 2H), 7.00 to 7.24 (m, 16H), 7.71 (d, 2H) ), 7.89 (d, 2H)

(Synthesis Example (3): Synthesis Method of Compound Example [HTM-42])

A 50 ml four-headed flask was equipped with a thermometer and a condenser, and 5 g (0.011 mol) of compound (7), 1.9 g (0.015 mol) of sodium sulfite and 15 ml of water were added and refluxed for 12 hours. After completion of the reaction, the obtained target product was purified by column chromatography to obtain 3.9 g (81%) of [HTM-42].
The above compound was confirmed to be [HTM-42] by nuclear magnetic resonance ( ¹ H-NMR).
¹ H-NMR (300 MHz, DMSO) δ ppm: 4.29 (s, 1H), 7.00 to 7.24 (m, 16H), 7.71 (d, 2H), 7.89 (d, 2H) ), 8.5 (s, 1H)

(Compound Example (4): Compound Example [HTM-52] Synthesis Method)

  A 100 ml four-headed flask was equipped with a nitrogen inlet tube, a thermometer and a condenser, and 4- (di-p-toluylamino) benzaldehyde (9) 5 g (16.6 mmol), diethyl (4-iodobenzyl) phosphonate (10) 7.64 g (21.6 mmol) and N, N-dimethylformamide 15 ml were added and sufficiently dissolved under a nitrogen stream.

  To this, 2.98 g (26.5 mmol) of tert-butoxypotassium was added little by little. After completion of the addition, the mixture was reacted at 45 ° C. for 1 hour. To this, 70 ml of water was added, extracted with ethyl acetate, and then washed with water until neutrality.

  The organic layer was dried and then concentrated, and purified by column chromatography. 8.0 g (yield; 96.2%) of pale yellow crystals (E) -4- (4-iodostyryl) -N, N-di-p-toluylaniline (11) was obtained.

A 100 ml four-headed flask was equipped with a nitrogen inlet tube, a thermometer, and a condenser, and (E) -4- (4-iodostyryl) -N, N-di-p-toluylaniline (11) 7.0 g (14 mmol) , Pd (PPh ₃ ) ₂ Cl ₂ , 235.1 mg (0.335 mmol), 1,4-bis (diphenylphosphino) butane 0.3 g (0.70 mmol), 1,8-diazabicyclo [5.4.0] ] 10.6 g (0.07 mol) of -7-undecene (DBU) and 30 ml of dimethyl sulfoxide (DMSO) were added. To this, 1 g (0.014 mol) of propiolic acid (12) was added little by little. After completion of the addition, the reaction was carried out at 50 ° C. for 5 hours. After completion of the reaction, ethyl acetate was added, and the target product was extracted with a saturated aqueous solution of sodium hydrogen carbonate, and the extracted aqueous solution was acidified to pH 2 to obtain an crystals. This was purified by column chromatography, and dark yellow crystals (E) -3- (4- (4- (di-p-toluylamino) styryl) phenyl) propionic acid [HTM-52] 3.84 g (yield) 62%).
The above compound was confirmed to be [HTM-52] by nuclear magnetic resonance ( ¹ H-NMR).
¹ H-NMR (300 MHz, DMSO) δ ppm: 2.32 (s, 6H), 6.90 (s, 2H), 7.15 to 7.18 (m, 10H), 7.43 to 7.51 (M, 4H), 7.89 (d, 2H), 12.09 (s, 1H)

<Metal oxide fine particles surface-modified with a hole transporting compound>
Next, metal oxide fine particles whose surface is modified with a hole transporting compound will be described.

  The metal oxide fine particles according to the present invention are metal oxide fine particles whose surface is modified with a hole transporting compound having the structure represented by the general formula (1) (hereinafter also simply referred to as “surface-modified metal oxide fine particles”). .)

(Metal oxide fine particles)
The metal oxide fine particles according to the present invention are preferably metal oxide fine particles including transition metals. For example, silica (silicon dioxide), magnesium oxide, zinc oxide, lead oxide, aluminum oxide, tantalum oxide, indium oxide, bismuth oxide, yttrium oxide, cobalt oxide, copper oxide, manganese oxide, selenium oxide, iron oxide, zirconium oxide, Examples include metal oxide fine particles such as germanium oxide, tin oxide, titanium oxide, niobium oxide, molybdenum oxide, and vanadium oxide, and among them, any of tin oxide fine particles, titanium oxide fine particles, zinc oxide fine particles, or alumina fine particles. It is preferable because the wear resistance of the surface protective layer can be improved.

  The metal oxide fine particles are preferably prepared by a known production method, for example, a general production method such as a gas phase method, a chlorine method, a sulfuric acid method, a plasma method, or an electrolytic method.

  The number average primary particle size of the metal oxide fine particles is preferably in the range of 1 to 300 nm. Especially preferably, it is the range of 3-100 nm.

(Measuring method of metal oxide particle size)
The particle size (number average primary particle size) of the metal oxide fine particles is a photographic image obtained by taking an enlarged photograph of 10,000 times with a scanning electron microscope (manufactured by JEOL Ltd.) and randomly capturing 300 particles with a scanner. An automatic image processing analyzer “Luzex AP (LUZEX® AP)” (manufactured by Nireco Co., Ltd.) Software Ver. Using 1.32, binarization is performed, the horizontal ferret diameter is calculated, and the average value is calculated as the number average primary particle diameter. Here, the horizontal ferret diameter refers to the length of a side parallel to the x-axis of the circumscribed rectangle when the image of the metal oxide fine particles is binarized.

(Surface modification method of metal oxide fine particles)
In the surface modification of the metal oxide fine particles, 0.1-100 parts by mass of a hole transporting compound having an acidic group is added to 100 parts by mass of the metal oxide fine particles using a wet media dispersion type apparatus. It is preferable to do. Within this range, there is no deterioration in electrical characteristics due to the provision of the surface protective layer, and the effect of improving the image memory can be obtained. Moreover, it is preferable to carry out surface modification using 50-5000 mass parts of solvent with respect to 100 mass parts of metal oxide fine particles.

  The solvent used for the surface modification with the hole transporting compound having an acidic group may be any solvent that can disperse the metal oxide fine particles well and dissolve the hole transporting compound having an acidic group. Examples include xylene, methylene chloride, methyl ethyl ketone, cyclohexane, acetone, ethyl acetate, butyl acetate, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane.

  The wet media dispersion type device, which is a surface modification device used in the present invention, is a method of filling fine particles of metal oxide by filling beads in a container as a medium and rotating a stirring disk mounted perpendicularly to the rotation axis at high speed. Is a device having a step of crushing and pulverizing / dispersing the aggregated particles, and having a structure in which the metal oxide fine particles are sufficiently dispersed when the surface modification is performed on the metal oxide fine particles and also has an acidic group There are no problems as long as the surface can be modified with a transporting compound, and various types such as a vertical type, a horizontal type, a continuous type, and a batch type can be adopted.

  Specifically, a sand mill, ultra visco mill, pearl mill, glen mill, dyno mill, agitator mill, dynamic mill and the like can be used. These dispersion-type devices are pulverized and dispersed by impact crushing, friction, shearing, shear stress, etc., using a grinding medium (media) such as balls and beads.

  As the beads used in the sand grinder mill, balls made of glass, alumina, zircon, zirconia, steel, flint stone or the like can be used, but those made of zirconia or zircon are particularly preferable. Further, as the size of the beads, those having a diameter of about 1 to 2 mm are usually used, but in the present invention, those having a diameter of about 0.1 to 1.0 mm are preferably used.

  Various materials such as stainless steel, nylon and ceramic can be used for the disk and container inner wall used in the wet media dispersion type apparatus. In the present invention, the disk and container inner wall made of ceramic such as zirconia or silicon carbide are particularly used. Is preferred.

  Hereinafter, a surface modification method for producing metal oxide fine particles that are surface-coated (surface modified) with a hole transporting compound having an acidic group in a more uniform and finer manner will be described in detail.

  That is, the surface of the metal oxide fine particles is simultaneously refined by wet pulverizing a slurry (suspension of solid particles) containing the metal oxide fine particles and the hole transporting compound having an acidic group. Modification proceeds. When this slurry is wet pulverized, it may be pulverized at a temperature of 40 to 80 ° C.

  This is because the reaction between the hole transporting compounds having an acidic group does not occur even when the treatment is carried out at a temperature, and thus heating can be performed to promote the reaction with the metal oxide fine particles.

After completion of this treatment, the solvent is removed, heat treatment is performed, and powderization is performed, so that metal oxide fine particles whose surface is modified with a hole transporting compound having a uniform and finer acidic group can be obtained. Here, it is considered that an acidic group such as a carboxy group possessed by the hole transporting compound forms an ionic bond through a dehydration reaction with a hydroxy group on the surface of the metal oxide fine particles.
The metal oxide fine particles according to the present invention have a coupling agent having a radical polymerizable functional group, in particular, an acryloyl group or a methacryloyl group before or after the surface modification with the hole transporting compound having an acidic group, or at the same time. The surface may be modified with a silane coupling agent (also referred to as “surface treatment agent”).
Examples of the silane coupling agent having an acryloyl group or a methacryloyl group include the following compounds.

_{S-1 CH 2 = CHSi (} CH 3) (OCH 3) 2
_{S-2 CH 2 = CHSi (} OCH 3) 3
S-3 CH ₂ = CHSiCl _{3
S-4 CH 2 = CHCOO (} CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-5 CH 2 = CHCOO (} CH 2) 2 Si (OCH 3) 3
_{S-6 CH 2 = CHCOO (} CH 2) 3 Si (CH 3) (OCH 3) 2
_{S-7 CH 2 = CHCOO (} CH 2) 3 Si (OCH 3) 3
_{S-8 CH 2 = CHCOO (} CH 2) 2 Si (CH 3) Cl 2
_{S-9 CH 2 = CHCOO (} CH 2) 2 SiCl 3
_{S-10 CH 2 = CHCOO (} CH 2) 3 Si (CH 3) Cl 2
S-11 CH ₂ = CHCOO (CH ₂ ) ₃ SiCl _{3
S-12 CH 2 = C (} CH 3) COO (CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-13 CH 2 = C (} CH 3) COO (CH 2) 2 Si (OCH 3) 3
_{S-14 CH 2 = C (} CH 3) COO (CH 2) 3 Si (CH 3) (OCH 3) 2
_{S-15 CH 2 = C (} CH 3) COO (CH 2) 3 Si (OCH 3) 3
_{S-16 CH 2 = C (} CH 3) COO (CH 2) 2 Si (CH 3) Cl 2
_{S-17 CH 2 = C (} CH 3) COO (CH 2) 2 SiCl 3
_{S-18 CH 2 = C (} CH 3) COO (CH 2) 3 Si (CH 3) Cl 2
_{S-19 CH 2 = C (} CH 3) COO (CH 2) 3 SiCl 3
_{S-20 CH 2 = CHSi (} C 2 H 5) (OCH 3) 2
S-21 CH ₂ ═C (CH ₃ ) Si (OCH ₃ ) _{3
S-22 CH 2 = C (} CH 3) Si (OC 2 H 5) 3
_{S-23 CH 2 = CHSi (} OCH 3) 3
_{S-24 CH 2 = C (} CH 3) Si (CH 3) (OCH 3) 2
_{S-25 CH 2 = CHSi (} CH 3) Cl 2
_{S-26 CH 2 = CHCOOSi (} OCH 3) 3
_{S-27 CH 2 = CHCOOSi (} OC 2 H 5) 3
_{S-28 CH 2 = C (} CH 3) COOSi (OCH 3) 3
_{S-29 CH 2 = C (} CH 3) COOSi (OC 2 H 5) 3
_{S-30 CH 2 = C (} CH 3) COO (CH 2) 3 Si (OC 2 H 5) 3

  Among the above, S-4 to S-7, which are compounds in which the acryloyl group has an ether bond and has a methoxy group, and S-12 to S-, which are compounds in which the methacryloyl group has an ether bond and has a methoxy group at the terminal 15 and S-24 are more preferred.

  In addition, the amount of the silane coupling agent having a radical polymerizable functional group to the metal oxide fine particles was adjusted such that the amount of the silane coupling agent having a radical polymerizable functional group was 100. 1-200 mass parts is preferable, and 7-70 mass parts is more preferable.

<Charge transport agent>
The surface protective layer according to the present invention contains a charge transport agent. As the charge transporting agent, a general material having a charge transporting function can be contained, but the molecular weight is preferably in the range of 250 to 800. When the molecular weight is 250 or more, it is possible to prevent the charge transport function from being deteriorated, and the image memory preventing property is improved. Further, when the molecular weight is 800 or less, it is easy to maintain the surface hardness of the surface protective layer. Although the example of a compound is shown below, this invention is not limited to these.

  The charge transfer agent can be synthesized by a known synthesis method, for example, the method described in JP-A-2006-143720.

  The molecular weight of the charge transfer agent was two significant digits after the decimal point.

<Binder resin>
The binder resin for the surface protective layer may be a polymer having high hardness such as polycarbonate or polyarylate, but it may contain a resin obtained by polymerizing (curing and forming) a crosslinkable polymerizable compound. This is preferable because the wear resistance of the protective layer is improved.

(Crosslinkable polymerizable compound)
The crosslinkable polymerizable compound is preferably a monomer that is polymerized (cured) by irradiation with actinic rays such as ultraviolet rays or electron beams, and becomes a resin generally used as a binder resin for a photoreceptor, such as polystyrene and polyacrylate. Styrene monomers, acrylic monomers, methacrylic monomers, vinyl toluene monomers, vinyl acetate monomers, and N-vinyl pyrrolidone monomers are preferred. Among these, acryloyl group (CH ₂ ═CHCO—) or methacryloyl group (CH ₂ ═CCH ₃ CO—) is used because it is easily polymerized by heat or light, and can be cured in a small amount of light or in a short time. A radically polymerizable compound is particularly preferred.

  In the present invention, these crosslinkable polymerizable compounds may be used alone or in admixture of two or more.

  Examples of the crosslinkable polymerizable compound are shown below. The number of Ac groups or the number of Mc groups described below represents the number of acryloyl groups or methacryloyl groups in one molecule.

  However, in the above, R is shown below.

  In the above, R ′ is shown below.

  In the present invention, the crosslinkable polymerizable compound is preferably a compound having a functional group (reactive group) of 3 or more. Further, the crosslinkable polymerizable compound may be used in combination of two or more kinds of compounds, but in this case as well, the crosslinkable polymerizable compound preferably uses 50% by mass or more of the compound having 3 or more functional groups. .

Further, the metal oxide fine particles whose surface is modified with a hole transporting compound having an acidic group is preferably added in an amount of 50 to 200 parts by mass with respect to 100 parts by mass of the binder resin or the crosslinkable polymerizable compound. Preferably, it is 100-150 mass parts. Within this range, the effect of a strong surface protective layer with higher wear resistance can be obtained. Moreover, since sufficient hole transport performance is obtained, electrophotographic characteristics are not impaired.
The charge transport agent contained in the surface protective layer is preferably added in an amount of 2 to 60 parts by weight, and 5 to 50 parts by weight, based on 100 parts by weight of the binder resin or the crosslinkable polymerizable compound in the surface protective layer. Part is more preferable, and it is still more preferable that it is 10-35 mass parts.

(Other additives)
Further, the surface protective layer according to the present invention may further contain various antioxidants. Various lubricant particles can also be added. As the lubricant particles, for example, fluorine atom-containing resin particles can be added. Fluorine atom-containing resin particles include tetrafluoroethylene resin, trifluorochloroethylene resin, trifluorochloroethylene propylene resin, hexafluorochloroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluoride It is preferable to appropriately select one or two or more of the ethylene dichloride resin and copolymers thereof, and particularly preferred are ethylene tetrafluoride resin and vinylidene fluoride resin. The ratio of the lubricant particles in the surface protective layer is preferably 5 to 70 parts by mass and more preferably 10 to 60% by mass with respect to 100 parts by mass of the binder resin. The lubricant particles preferably have a number average primary particle size of 0.01 to 1 μm. Particularly preferred is 0.05 to 0.5 μm. The molecular weight of the resin can be appropriately selected and is not particularly limited.

<Formation of surface protective layer>
The surface protective layer is composed of a binder resin, a charge transport agent (hole transport agent), metal oxide fine particles surface-modified with a hole transport compound having an acidic group, and other crosslinkable polymerizable compounds as required. A coating solution prepared by adding a polymerization initiator, lubricant particles, and the like can be applied to the surface of the photosensitive layer by a known method, and then subjected to natural drying or heat drying, followed by curing. The thickness of the surface protective layer is preferably in the range of 0.2 to 10 μm, and more preferably in the range of 0.5 to 6 μm.

(solvent)
Solvents used for forming the surface protective layer include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-2-propanol, benzyl alcohol, methyl isopropyl ketone, and methyl isobutyl. Ketone, methyl ethyl ketone, cyclohexane, toluene, xylene, methylene chloride, ethyl acetate, butyl acetate, 2-methoxyethanol, 2-ethoxyethanol, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine, diethylamine, and the like. It is not limited to these.

(Polymerization initiator)
Examples of a method for polymerizing a crosslinkable polymerizable compound that can be used in the surface protective layer according to the present invention include a method using an electron beam cleavage reaction and a method using light and heat in the presence of a radical polymerization initiator. A polymerization reaction can be performed. When performing a polymerization reaction using a radical polymerization initiator, both a photopolymerization initiator and a thermal polymerization initiator can be used as the polymerization initiator. Further, both light and heat initiators can be used in combination.

  Examples of the polymerization initiator that can be used in the surface protective layer according to the present invention include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylazobisvaleronyl) and 2,2 Azo compounds such as' -azobis (2-methylbutyronitrile), benzoyl peroxide (BPO), di-tert-butyl hydroperoxide, tert-butyl hydroperoxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromoperoxide And thermal polymerization initiators such as peroxides such as methylbenzoyl and lauroyl peroxide.

  Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1 (Irgacure 369: manufactured by BASF Japan Ltd.), 2-hydroxy-2-methyl-1 Acetophenones such as phenylpropan-1-one, 2-methyl-2-morpholino (4-methylthiophenyl) propan-1-one and 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime Or ketal photopolymerization initiator, benzoin, benzoin methyl ether, benzoy Benzoin ether photopolymerization initiators such as ethyl ether, benzoin isobutyl ether and benzoin isopropyl ether, benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoylphenyl ether, Benzophenone photopolymerization initiators such as acrylated benzophenone and 1,4-benzoylbenzene, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone and 2,4-dichlorothioxanthone And thioxanthone photopolymerization initiators.

  Other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine Oxide (Irgacure 819: manufactured by BASF Japan), bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10-phenanthrene, acridine compound, triazine And compounds and imidazole compounds. Moreover, what has a photopolymerization acceleration effect can also be used individually or in combination with the said photoinitiator. Examples include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, ethyl (2-dimethylamino) benzoate, and 4,4′-dimethylaminobenzophenone.

  The polymerization initiator used in the surface protective layer according to the present invention is preferably a photopolymerization initiator, preferably an alkylphenone compound or a phosphine oxide compound, and more preferably an α-hydroxyacetophenone structure or an acylphosphine oxide structure. Initiators having are preferred.

  These polymerization initiators may be used alone or in combination of two or more. Content of a polymerization initiator is 0.1-20 mass parts with respect to 100 mass parts of a crosslinkable polymeric compound, Preferably it is 0.5-10 mass parts.

(Surface protection layer curing method)
In the present invention, the polymerization reaction of the surface protective layer is performed by irradiating the coating film with active rays to generate radicals, polymerize, and cure by forming a cross-linking bond between the molecules and within the molecule by a cross-linking reaction. Is preferably generated. The actinic rays are preferably light such as ultraviolet rays and visible light and electron beams, and ultraviolet rays are particularly preferred from the viewpoint of ease of use.

As the ultraviolet light source, any light source that generates ultraviolet light can be used without limitation. For example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a flash (pulse) xenon, or an ultraviolet LED can be used. Irradiation conditions vary depending on each lamp, but the irradiation amount of active rays is usually in the range of 1 to ²⁰ mJ / cm ² , preferably in the range of 5 to 15 mJ / cm ² . The output voltage of the light source is preferably in the range of 0.1 to 5 kW, more preferably in the range of 0.5 to 3 kW.

  As an electron beam source, there is no particular limitation on the electron beam irradiation apparatus, and generally, an electron beam accelerator for electron beam irradiation is a curtain beam type that is relatively inexpensive and can provide a large output. Used. The acceleration voltage during electron beam irradiation is preferably 100 to 300 kV. The absorbed dose is preferably 0.005 Gy to 100 kGy (0.5 rad to 10 Mrad).

  The irradiation time of the active ray is a time for obtaining the necessary irradiation amount of the active ray, specifically 0.1 seconds to 10 minutes is preferable, and 1 second to 5 minutes is more preferable from the viewpoint of polymerization efficiency or work efficiency. It is said.

  In the present invention, the surface protective layer can be dried before and after irradiation with active rays and during irradiation with active rays, and the timing for drying can be appropriately selected in combination with the irradiation conditions of active rays. The drying conditions for the surface protective layer can be appropriately selected depending on the type of solvent used in the coating solution and the thickness of the surface protective layer. The drying temperature is preferably room temperature to 180 ° C, particularly preferably 80 to 140 ° C. The drying time is preferably 1 to 200 minutes, particularly preferably 5 to 100 minutes. In the present invention, the amount of solvent contained in the surface protective layer can be controlled in the range of 20 to 75 ppm by drying the surface protective layer under the above drying conditions.

  By providing the surface protective layer on the photosensitive layer as described above, it is possible to increase the hardness of the surface of the photoreceptor, improve the wear resistance, and improve the durability.

  Next, constituent materials other than the surface protective layer constituting the photoreceptor of the present invention will be described.

<Conductive support>
The support used in the present invention may be any one as long as it has conductivity, for example, a metal such as aluminum, copper, chromium, nickel, zinc and stainless steel formed into a drum or sheet, aluminum or copper Metal foil such as laminated on plastic film, aluminum, indium oxide and tin oxide deposited on plastic film, metal with conductive layer applied alone or with binder resin, plastic film and For example, paper.

《Middle layer》
In the present invention, an intermediate layer having a barrier function and an adhesive function may be provided between the conductive support and the photosensitive layer.

  The intermediate layer can be formed by dip coating or the like by dissolving a binder resin such as casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide, polyurethane and gelatin in a known solvent. Of these, an alcohol-soluble polyamide resin is preferred.

  Further, inorganic fine particles such as various metal oxide fine particles can be contained for the purpose of adjusting the resistance of the intermediate layer. For example, various metal oxide fine particles such as alumina, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, ultrafine particles such as indium oxide doped with tin, tin oxide doped with antimony, and zirconium oxide. Can be used.

  These inorganic fine particles may be used alone or in combination. When two or more types are mixed, they may take the form of a solid solution or fusion. The average particle size of such inorganic fine particles is preferably 0.3 μm or less, more preferably 0.1 μm or less.

  As the solvent used for the intermediate layer, a solvent in which inorganic fine particles such as metal oxide fine particles are well dispersed and the polyamide resin is dissolved is preferable. Specifically, alcohols having 2 to 4 carbon atoms such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol and the like are excellent in solubility and coating performance of the polyamide resin. In addition, examples of co-solvents that can be used in combination with the above-mentioned solvent to improve storage stability and fine particle dispersibility and obtain preferable effects include methanol, benzyl alcohol, toluene, methylene chloride, cyclohexanone, and tetrahydrofuran.

  The concentration of the binder resin is appropriately selected according to the thickness of the intermediate layer and the production rate.

  The mixing ratio of the inorganic fine particles to the binder resin when the inorganic fine particles are dispersed is preferably 20 to 400 parts by mass, more preferably 50 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

  As a means for dispersing the inorganic fine particles, an ultrasonic disperser, a ball mill, a sand grinder, a homomixer or the like can be used, but is not limited thereto.

  The method for drying the intermediate layer after coating can be appropriately selected according to the type of solvent and the layer thickness, but thermal drying is preferred.

  The thickness of the intermediate layer is preferably 0.1 to 15 μm, and more preferably 0.3 to 10 μm.

<Photosensitive layer>
As described above, the photosensitive layer has both the function of generating light by absorbing light and the function of transporting charge, and the layer structure of the photosensitive layer contains a charge generating material and a charge transporting material. A single layer configuration may be used, or a stacked configuration of a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material may be used.

(Charge generation layer)
The charge generation layer used in the present invention preferably contains a charge generation material and a binder resin, and is formed by dispersing and coating the charge generation material in a binder resin solution.

  As the charge generation material, known charge generation materials can be used, azo raw materials such as Sudan Red and Diane Blue, quinone pigments such as pyrenequinone and anthanthrone, quinocyanine pigments, perylene pigments, indigo and indigo pigments such as thioindigo. And phthalocyanine pigments, but are not limited thereto. These charge generating materials can be used alone or in a form dispersed in a known resin.

  As the binder resin of the charge generation layer, a known resin can be used, for example, polystyrene resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, Polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, and copolymer resin containing two or more of these resins (for example, vinyl chloride-vinyl acetate copolymer resin, chloride) Vinyl-vinyl acetate-maleic anhydride copolymer resin) and poly-vinylcarbazole resin, but are not limited thereto.

  The charge generation layer is formed by dispersing the charge generation material in a solution obtained by dissolving the binder resin in a solvent using a disperser to prepare a coating solution, and applying the coating solution to a certain film thickness using a coating device. It is preferable to prepare the film by drying.

  Solvents for dissolving and coating the binder resin used in the charge generation layer include, for example, toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate, methanol, ethanol, propanol, Examples include butanol, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine, and diethylamine, but are not limited thereto.

  As a means for dispersing the charge generating material, an ultrasonic disperser, a ball mill, a sand grinder, a homomixer, or the like can be used, but is not limited thereto.

  The mixing ratio of the charge generating material to the binder resin is preferably 1 to 600 parts by mass, more preferably 50 to 500 parts by mass with respect to 100 parts by mass of the binder resin. The thickness of the charge generation layer varies depending on the characteristics of the charge generation material, the characteristics of the binder resin, the mixing ratio, and the like, but is preferably 0.01 to 5 μm, more preferably 0.05 to 3 μm. It should be noted that the coating solution for the charge generation layer can prevent the occurrence of image defects by filtering foreign matter and aggregates before coating. It can also be formed by vacuum deposition of the pigment.

(Charge transport layer)
The charge transport layer used in the photoreceptor of the present invention contains a charge transport material (CTM) and a binder resin, and is formed by dissolving and coating the charge transport material in a binder resin solution.

  As the charge transport material, known charge transport materials can be used, for example, carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, Bisimidazolidine derivatives, styryl compounds, hydrazone compounds, pyrazoline compounds, oxazolone derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, phenylenediamine derivatives, stilbene derivatives, benzidine Derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene and triphenylamine Mention may be made of the emissions derivatives, and the like. You may use these in mixture of 2 or more types.

  A known resin can be used as the binder resin for the charge transport layer, and polycarbonate resin, polyacrylate resin, polyester resin, polystyrene resin, styrene-acrylonitrile copolymer resin, polymethacrylic ester resin, and styrene-methacrylic acid. Examples include ester copolymer resins, and polycarbonate is preferred. Furthermore, BPA, BPZ, dimethyl BPA, BPA-dimethyl BPA copolymer and the like are preferable in terms of crack resistance, wear resistance, and charging characteristics.

  The charge transport layer is preferably formed by dissolving the binder resin and the charge transport material to prepare a coating solution, applying the coating solution to a certain film thickness with a coating machine, and drying the coating film.

  Examples of the solvent for dissolving the binder resin and the charge transport material include toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, and tetrahydrofuran. 1,4-dioxane, 1,3-dioxolane, pyridine, diethylamine, and the like, but are not limited thereto.

  The mixing ratio of the charge transport material to the binder resin is preferably 10 to 500 parts by mass, more preferably 20 to 100 parts by mass with respect to 100 parts by mass of the binder resin.

  The thickness of the charge transport layer varies depending on the characteristics of the charge transport material, the characteristics of the binder resin, the mixing ratio, and the like, but is preferably 5 to 40 μm, more preferably 10 to 30 μm.

  An antioxidant, an electronic conductive agent, a stabilizer and the like may be added to the charge transport layer. For the antioxidant, those described in Japanese Patent Application No. 11-200135 and for the electronic conductive agent are described in Japanese Patent Application Laid-Open Nos. 50-137543 and 58-76483.

《Photoconductor application method》
Each layer such as an intermediate layer, a charge generation layer, a charge transport layer and a surface protective layer constituting the photoreceptor of the present invention can be formed by a known coating method. Specific examples include a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a blade coating method, a beam coating method, and a circular amount regulating coating method (circular slide hopper coating method). The circular amount regulation type coating method is described in, for example, Japanese Patent Application Laid-Open Nos. 58-189061 and 2005-275373.

≪Electrophotographic image forming device≫
The electrophotographic photosensitive member of the present invention is suitably used for an electrophotographic image forming apparatus having at least a charging unit for charging the electrophotographic photosensitive member, an exposure unit, a developing unit, and a transfer unit (primary transfer unit).
The electrophotographic image forming apparatus using the electrophotographic photosensitive member of the present invention will be described below. FIG. 2 is a cross-sectional configuration diagram of a full-color electrophotographic image forming apparatus showing an example of an embodiment of the present invention. In the following description, it is assumed that the electrophotographic photoreceptor of the present invention is used for the photoreceptors 1Y, 1M, 1C, and 1Bk.

  This color image forming apparatus is called a tandem color image forming apparatus, and includes four sets of image forming units (also referred to as image forming units) 10Y, 10M, 10C, and 10Bk, and an endless belt-shaped intermediate transfer body unit 7a. And a sheet feeding means 21 and a fixing means 24. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

  The image forming unit 10Y for forming a yellow image includes a charging unit (charging step) 2Y, an exposure unit (exposure step) 3Y, and a developing unit disposed around a drum-shaped photoconductor 1Y as a first image carrier. A unit (developing step) 4Y, a primary transfer roller 5Y as a primary transfer unit (primary transfer step), and a cleaning unit 6Y. An image forming unit 10M for forming a magenta image includes a drum-shaped photosensitive member 1M as a first image carrier, a charging unit 2M, an exposure unit 3M, a developing unit 4M, a primary transfer roller 5M as a primary transfer unit, and It has a cleaning means 6M. An image forming unit 10C for forming a cyan image includes a drum-shaped photoreceptor 1C as a first image carrier, a charging unit 2C, an exposure unit 3C, a developing unit 4C, a primary transfer roller 5C as a primary transfer unit, and It has cleaning means 6C. The image forming unit 10Bk that forms a black image includes a drum-shaped photoreceptor 1Bk as a first image carrier, a charging unit 2Bk, an exposure unit 3Bk, a developing unit 4Bk, a primary transfer roller 5Bk as a primary transfer unit, and a cleaning unit. 6Bk.

  The four sets of image forming units 10Y, 10M, 10C, and 10Bk are centered around the photoreceptors 1Y, 1M, 1C, or 1Bk, charging means 2Y, 2M, 2C, or 2Bk, and exposure means 3Y, 3M, 3C, or 3Bk. The developing means 4Y, 4M, 4C or 4Bk and the cleaning means 6Y, 6M, 6C or 6Bk for cleaning the photoreceptors 1Y, 1M, 1C or 1Bk.

  The image forming units 10Y, 10M, 10C, and 10Bk have the same configuration except that the colors of the toner images to be formed on the photoreceptors 1Y, 1M, 1C, and 1Bk are different, and the image forming unit 10Y is taken as an example in detail. Explained.

  The image forming unit 10Y includes a charging unit 2Y (hereinafter also referred to as “charger 2Y”), an exposure unit 3Y, a developing unit 4Y, and a cleaning unit 6Y around a photoconductor 1Y that is an image forming body. A yellow (Y) toner image is formed on the body 1Y. In the present embodiment, in the image forming unit 10Y, at least the photoreceptor 1Y, the charging unit 2Y, the developing unit 4Y, and the cleaning unit 6Y are provided so as to be integrated.

  The charging unit 2Y is a unit that applies a uniform potential to the photoreceptor 1Y. In this embodiment, a corona discharge type charger 2Y is used as the photoreceptor 1Y.

  The exposure unit 3Y is a unit that performs exposure based on an image signal (yellow) on the photoreceptor 1Y to which a uniform potential is applied by the charger 2Y, and forms an electrostatic latent image corresponding to a yellow image. As the exposure means 3Y, an exposure element 3Y composed of LEDs and light-emitting elements arranged in an array in the axial direction of the photoreceptor 1Y and an imaging element (trade name: SELFOC (registered trademark) lens), or A laser optical system or the like is used.

  The developing means 4Y includes, for example, a developing sleeve and an organic photosensitive member that have a built-in magnet and rotate while holding the developer, and a voltage application that applies a DC and AC bias voltage or a DC or AC bias voltage between the developing sleeve and the developing sleeve. It consists of a device.

  The endless belt-shaped intermediate transfer body unit 7a has an endless belt-shaped intermediate transfer body 70 as a semiconductive endless belt-shaped second image carrier wound around a plurality of rollers and rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10Bk is sequentially transferred onto a rotating endless belt-shaped intermediate transfer body 70 by primary transfer rollers 5Y, 5M, 5C, and 5Bk as primary transfer means. Thus, a synthesized color image is formed. A transfer material P as a transfer material (a support for carrying a fixed final image: for example, plain paper, a transparent sheet, etc.) housed in the paper feed cassette 20 is fed by a paper feed means 21 and a plurality of intermediates. After passing through the rollers 22A, 22B, 22C, 22D and the registration roller 23, they are conveyed to a secondary transfer roller 5b as a secondary transfer means, and are secondarily transferred onto the transfer material P, and the color images are collectively transferred. The transfer material P onto which the color image has been transferred is fixed by the fixing means 24, is sandwiched between the paper discharge rollers 25, and is placed on a paper discharge tray 26 outside the apparatus. Here, a toner image transfer support formed on a photosensitive member such as an intermediate transfer member or a transfer material is collectively referred to as a transfer medium.

  On the other hand, after the color image is transferred to the transfer material P by the secondary transfer roller 5b as the secondary transfer means, the residual toner is removed by the cleaning means 6b from the endless belt-shaped intermediate transfer body 70 in which the transfer material P is separated by curvature. The

  During the image forming process, the primary transfer roller 5Bk is always in contact with the photoreceptor 1Bk. The other primary transfer rollers 5Y, 5M, and 5C are in contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roller 5b contacts the endless belt-shaped intermediate transfer body 70 only when the transfer material P passes through the secondary transfer roller 5b.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10Bk, and an endless belt-shaped intermediate transfer body unit 7a.

  The image forming units 10Y, 10M, 10C, and 10Bk are arranged in tandem in the vertical direction. An endless belt-like intermediate transfer body unit 7a is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1Bk in the drawing. The endless belt-shaped intermediate transfer body unit 7a includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rollers 71, 72, 76, 73, and 74, primary transfer rollers 5Y, 5M, 5C, and 5Bk, and a cleaning unit 6b. It consists of.

≪Process cartridge≫
As an electrophotographic image forming apparatus of the present invention, a process comprising the electrophotographic photosensitive member of the present invention and at least one of a charging unit (charging unit), an exposure unit (exposure unit) or a developing unit (developing unit) as an integral unit. It is preferable that the image forming unit is configured as a cartridge (image forming unit) so that the image forming unit can be inserted into and removed from the main body of the electrophotographic image forming apparatus. In addition to a charging unit, an exposure unit, and a developing unit, a process cartridge (image formation) having at least one of a transfer unit (transfer unit), a separation unit (separator), or a cleaning unit (cleaning unit) together with a photosensitive member. A single image forming unit that is detachably attached to the apparatus main body, and may be detachable using guide means such as a rail of the apparatus main body.

  The electrophotographic image forming apparatus of the present invention is generally applicable to electrophotographic image forming apparatuses such as electrophotographic copying machines, laser printers, LED printers, and liquid crystal shutter printers, but also displays, recordings, and light printing using electrophotographic technology. It can also be widely applied to apparatuses such as plate making and facsimile.

  The embodiments to which the present invention can be applied are not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of the present invention.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the examples, “parts” or “%” is used, but “parts by mass” or “mass%” is expressed unless otherwise specified.

<< Production of photoconductor >>
<Preparation of surface-modified metal oxide fine particles [1]>
Metal oxide fine particles (surface-modified metal oxide fine particles) surface-modified with a hole transporting compound having an acidic group were prepared as follows.

  100 parts by mass of “titanium oxide” having a number average primary particle size of 6 nm as metal oxide fine particles, 10 parts by mass of [HTM-1] as a hole transporting compound having an acidic group, and 1000 parts by mass of methyl ethyl ketone were mixed with a wet sand mill (particle size 0 0.5 mm alumina beads) and stirred and mixed at 30 ° C. for 1 hour at a rotational speed of 1000 rpm. Thereafter, methyl ethyl ketone and alumina beads are separated by filtration, and methyl ethyl ketone and titanium oxide fine particles are separated by a centrifugal separator. Drying was performed at ° C., and surface-modified metal oxide fine particles [1] were produced by modifying the surface of titanium oxide fine particles with a hole transporting compound [HTM-1] having an acidic group.

<Preparation of surface-modified metal oxide fine particles [2] to [27]>
In the production of the surface-modified metal oxide fine particles [1], the types of metal oxide fine particles, the number average primary particle size, the types of hole transporting compounds having acidic groups, and the amount of addition thereof are as shown in Table 1. Thus, surface-modified metal oxide fine particles [2] to [27] were produced.
However, among these, those having surface modification with a silane coupling agent having a radical polymerizable functional group may be modified by the following method before the surface modification of the hole transporting compound having an acidic group. The product obtained by surface modification with a silane coupling agent having an acid group is treated as the metal oxide fine particles, and the metal oxide fine particles are treated with acidic groups in the same manner as in the preparation of the surface modified metal oxide fine particles [1]. Surface-modified metal oxide fine particles were prepared by surface modification with a hole transporting compound containing

(Method of surface modification of metal oxide fine particles with a silane coupling agent having a radical polymerizable functional group)
The procedure for surface modification of the metal oxide fine particles with the silane coupling agent having a radical polymerizable functional group in the production of the surface modified metal oxide fine particles [2] will be described.
As a metal oxide fine particle, a mixed solution of 100 parts by mass of “titanium oxide” having a number average primary particle size of 10 nm and 5 parts of S-34 and 300 parts of a mixed solvent of toluene / isopropyl alcohol = 1/1 (mass ratio). Then, it was placed in a sand mill together with zirconia beads and stirred at about 40 ° C. at a rotational speed of 1500 rpm, and surface modification with a silane coupling agent having a radical polymerizable functional group of titanium oxide particles was performed. Furthermore, after taking out the said processing mixture, throwing into a Henschel mixer and stirring for 15 minutes at a rotational speed of 1500 rpm, it is dried at 120 degreeC for 3 hours, The surface of the titanium oxide by the silane coupling agent which has a radically polymerizable functional group The modification was completed, and surface-modified titanium oxide was obtained. By surface modification with the above-mentioned silane coupling agent having a radical polymerizable functional group, the particle surface of titanium oxide is coated with the compound of S-34. XRF analysis apparatus “XRF-1700 (manufactured by Shimadzu Corporation) This was confirmed by detecting the Si peak.

  In the preparation of the surface-modified metal oxide fine particles [3] to [27], those having surface modification with a silane coupling agent having a radical polymerizable functional group are those of the silane coupling agent having a radical polymerizable functional group. The types and the parts by mass of the compound and the metal oxide fine particles were the same as in the preparation of the surface-modified metal oxide fine particles [2] except that they were carried out as shown in Table 1. Surface modification with a silane coupling agent having a polymerizable functional group was performed.

<Preparation of surface-modified metal oxide fine particles [30]>
Titanium oxide (number average primary particle size 6 nm) as a metal oxide fine particle is not subjected to surface modification with a hole transporting compound having an acidic group, and the type of silane coupling agent having a radical polymerizable functional group, the compound and the metal Preparation of surface-modified metal oxide fine particles [2] except that surface modification with a silane coupling agent having a radical polymerizable functional group was carried out as shown in Table 1 under conditions for the mass parts of the oxide fine particles. In the same manner, surface-modified metal oxide fine particles [30] were produced.

<Preparation of surface-modified metal oxide fine particles [31]>
4- [2- (triethoxysilyl) ethyl which is a hole transporting compound having no acidic group instead of the hole transporting compound having an acidic group in the production of the surface modified metal oxide fine particles [1]. Using triphenylamine (HTM-A), the surface-modified metal oxide fine particles [31] were prepared using the metal oxide fine particles and the addition amounts thereof as shown in Table 1.

<Preparation of Photoreceptor 1>
Photoreceptor 1 was produced as follows.
A conductive support obtained by cutting the surface of a cylindrical aluminum support was prepared.

<Intermediate layer>
An intermediate layer coating solution having the following composition was prepared.
Binder resin: Polyamide resin “X1010” (manufactured by Daicel-Evonik)
1.0 part by mass Metal oxide fine particle: Titanium dioxide “SMT500SAS” (manufactured by Teica)
1.1 parts by mass Solvent: ethanol 20 parts by mass Using a sand mill as a disperser, dispersion was performed in a batch manner for 10 hours.
The coating solution was applied on the support by a dip coating method so that the layer thickness after drying at 110 ° C. for 20 minutes was 2 μm.

<Charge generation layer>
Charge generation materials:
Titanyl phthalocyanine pigment (a titanyl phthalocyanine pigment having a maximum diffraction peak at a position of at least 27.3 ° by Cu-Kα characteristic X-ray diffraction spectrum measurement)
20 parts by weight Binder resin:
Polyvinyl butyral resin “# 6000-C” (manufactured by Denki Kagaku Kogyo)
10 parts by mass Solvent: 700 parts by mass of t-butyl acetate 4-Methoxy-4-methyl-2-pentanone 300 parts by mass were mixed and dispersed for 10 hours using a sand mill to prepare a charge generation layer coating solution. This coating solution was applied onto the intermediate layer by a dip coating method to form a charge generation layer having a thickness of 0.3 μm after drying.

<Charge transport layer>
Charge transport material: 150 parts by mass of the following CTM-A Binder: Polycarbonate “Z300” (Mitsubishi Gas Chemical Co., Ltd.)
300 parts by mass Antioxidant: “Irganox (registered trademark) 1010” (manufactured by BASF Japan Ltd.)
6 parts by mass Solvent: Toluene / tetrahydrofuran = 1/9% by volume
2000 parts by mass Additive: Silicon oil “KF-54” (manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by mass was mixed and dissolved to prepare a charge transport layer coating solution. A charge transport layer having a thickness of 20 μm after drying for 60 minutes at 110 ° C. was formed on the charge generation layer by dip coating using this coating solution.

<Surface protective layer>
Metal oxide fine particles surface modified with a hole transporting compound having an acidic group:
Surface-modified metal oxide fine particles [1] 100 parts by mass Crosslinkable polymerizable compound: Exemplified compound “Mc-1” 100 parts by mass Solvent: 2-butanone 320 parts by mass After dispersing the above components for 10 hours using a sand mill, 15 parts by mass of charge transfer agent CTM-1, 80 parts by mass of tetrahydrofuran, polymerization initiator [1] (bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide: “Irgacure 819” (manufactured by BASF Japan) 8 parts by mass) was mixed and stirred under light shielding to dissolve, and a surface protective layer coating solution was prepared (light shielding during storage). A surface protective layer was applied to the photoreceptor having the coating solution prepared up to the charge transport layer using a circular slide hopper applicator. After coating, after drying for 20 minutes at room temperature (solvent drying step), irradiation was performed for 1 minute while rotating the photoconductor at a position of 100 mm using a metal halide lamp (500 W) (polymerization conditions (light) described later and Table 2). The polymerization conditions described in “light”.), A surface protective layer having a thickness of 3 μm was obtained.

  The polymerization initiator used for preparation of the surface protective layer is shown below.

Polymerization initiator [1]: bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide Polymerization initiator [2]: 1- (4-morpholinophenyl) -2- (dimethylamino) -2- (4- Methylbenzyl) -1-butanone polymerization initiator [3]: tert-butyl 2-ethylperoxyhexanoate Polymerization initiator [4]: N- (trifluoromethylsulfonyloxy) norborna-5-ene-2,3-di Carboximide polymerization initiator [5]: 1- (trifluoromethylsulfonyloxy) -3,3-dimethylbicyclo [2.2.1] heptan-2-one

<Preparation of photoconductors 2-33>
Photoconductors 2 to 33 were prepared in the same manner except that the materials used for the surface protective layer of photoconductor 1 and the polymerization conditions were changed as shown in Table 2.

<Preparation of Photoreceptor 34>
Photoreceptor 34 was produced in the same manner as Photoreceptor 1 except that the surface protective layer was formed as follows in the production of Photoreceptor 1.

<Surface protective layer>
Metal oxide fine particles surface modified with a hole transporting compound having an acidic group:
Surface-modified metal oxide fine particles [1] 100 parts by mass Binder:
Polycarbonate “Z300” (Mitsubishi Gas Chemical Co., Ltd.) 100 parts by mass Solvent: Isopropyl alcohol: Tetrahydrofuran = 1: 1 mixture
500 parts by mass Charge transfer agent: CTM-1 15 parts by mass The above components were dispersed for 10 hours using a sand mill to prepare a surface protective layer coating solution. A surface protective layer was applied to the photoreceptor having the coating solution prepared up to the charge transport layer using a circular slide hopper applicator. After coating, the film was dried at 100 ° C. for 50 minutes to obtain a surface protective layer having a thickness of 3 μm.

<Preparation of photoconductor 35>
A photoconductor 35 was produced in the same manner as the photoconductor 1 except that the surface protective layer was formed as follows in the production of the photoconductor 1.

<Surface protective layer>
Metal oxide fine particles surface modified with a hole transporting compound having an acidic group:
Surface-modified metal oxide fine particles [1] 100 parts by mass Binder:
Polyarylate “U-100” (manufactured by Unitika) 100 parts by mass Solvent: isopropyl alcohol: tetrahydrofuran = 1: 1 mixed solution
500 parts by mass Charge transfer agent: CTM-1 15 parts by mass The above components were dispersed for 10 hours using a sand mill to prepare a surface protective layer coating solution. A surface protective layer was applied to the photoreceptor having the coating solution prepared up to the charge transport layer using a circular slide hopper applicator. After coating, the film was dried at 100 ° C. for 50 minutes to obtain a surface protective layer having a thickness of 3 μm.

<Preparation of photoconductor 36 (for comparison)>
In the production of the photoreceptor 1, the surface-modified metal oxide fine particles [2] in the surface protective layer were changed to surface-modified metal oxide fine particles [30] (titanium oxide fine particles surface-modified with methylhydrogenpolysiloxane), and the crosslinkability was changed. A comparative photoconductor 36 was prepared as shown in Table 2 with respect to the types and addition amounts of the polymerizable compounds and polymerization initiators.

<Preparation of photoconductor 37 (for comparison)>
In the production of the photoreceptor 1, the surface-modified metal oxide fine particles [2] of the surface protective layer were surface-modified with the surface-modified metal oxide fine particles [31] (4- [2- (triethoxysilyl) ethyl] triphenylamine. A comparative photoconductor 37 was prepared by changing the type and addition amount of the crosslinkable polymerizable compound and the polymerization initiator as shown in Table 2.

<Production of Photoreceptor 38 (For Comparison)>
In the production of the photoreceptor 1, the surface-modified metal oxide fine particles [2] of the surface protective layer were surface-modified with the surface-modified metal oxide fine particles [31] (4- [2- (triethoxysilyl) ethyl] triphenylamine. A comparative photoconductor 38 was prepared by changing the type and amount of the crosslinkable polymerizable compound and the polymerization initiator as shown in Table 2.

<Preparation of photoconductor 39 (for comparison)>
A comparative photoconductor 39 was produced in the same manner as the photoconductor 2 except that the surface-modified metal oxide fine particles were not added to the surface protective layer in the production of the photoconductor 2.

  In the production of the photoreceptors 1 to 39, the polymerization reaction (curing reaction) of the surface protective layer was performed by photopolymerization or thermal polymerization, and each polymerization was performed under the following conditions.

  Polymerization conditions (light): After coating and drying for 20 minutes, a metal halide lamp (500 W) was used to irradiate the photoreceptor at a position of 100 mm for 1 minute to obtain a surface protective layer having a thickness of 3 μm.

  Polymerization conditions (heat): heated at 140 ° C. for 30 minutes to obtain a surface protective layer having a thickness of 3 μm.

<< Evaluation of photoconductor >>
The photoreceptor obtained as described above was mounted on a digital full-color multifunction peripheral “bizhub PRO C6501” (manufactured by Konica Minolta Co., Ltd.) which is an evaluation machine similar to the configuration of the image forming apparatus shown in FIG. As the light source, exposure light of a semiconductor laser having a wavelength of 780 nm was used.

  A 700,000 print-out printing durability test on a full-color A4 image with a color printing ratio of 2.5% for each color of Y, M, C, and Bk in a high-temperature, high-humidity environment (30 ° C, 85% RH) After that, the following evaluation was performed.

<1. Image memory>
After printing and printing durability test of 700,000 sheets in a high temperature and high humidity environment (30 ° C, 85% RH), an A4 image of a solid black image portion on the left half and a solid white image portion on the right half with respect to the paper passing direction Print 10 continuous images on a high-quality paper in the horizontal direction, and then print a uniform halftone image. The history of the solid black image portion and solid white image portion is printed in the printed halftone image. The difference (ΔID) between the reflection density of the area corresponding to the solid black image portion in the halftone image and the reflection density of the area corresponding to the solid white image portion in the halftone image is determined. Calculated and evaluated according to the following evaluation criteria.

  The reflection density was measured using a Macbeth reflection densitometer “RD-918” (manufactured by Macbeth).

(Evaluation criteria)
A: ΔID is 0.05 or less (good)
○: ΔID is greater than 0.05 and 0.10 or less (no problem in practical use)
X: ΔID is larger than 0.10 (there is a practical problem)

<2. Photoconductor wear amount>
Evaluation was made based on the difference in the film thickness of the photoreceptor before and after the 700,000 print-out printing durability test in a high-temperature and high-humidity environment (30 ° C. and 85% RH). The film thickness of the photoconductor is measured at 10 points at random at a uniform film thickness portion (the film thickness tends to be nonuniform at both ends of the photoconductor, so at least 3 cm at both ends), and the average value is measured as the film thickness of the photoconductor. Thickness. The film thickness measuring device is an eddy current film thickness measuring device “EDDY560C” (manufactured by Helmut Fischer), and the difference in the film thickness of the photoconductor before and after the printing durability test is used as the film thickness depletion amount. The amount of wear per 100 krot (100,000 revolutions) was defined as α value.

<3. Evaluation of film peeling of photoconductor>
The surface of the photoreceptor prepared as described above was evaluated for film peeling by a cross-cut tape method based on JIS K5400-1990. For items that are not specified, JIS K5400-1990 is followed. Show the procedure.
1. Fix the surface of the photoconductor, and make a cut on the grid using a cutter guide with a cutter knife in one central location. The interval between the cuts is 1 mm, and the number of “mass eyes” is based on 100. The grids peeled off at the interface part other than the interface between the surface protective layer and the photosensitive layer are excluded from the measurement, but if more than half of the grids are excluded from the measurement, the interval between the cuts is 1 mm. Measure in “mass-eye” intervals that can be expanded gradually.
2. Always use a new cutter knife when making cuts, and keep it at a constant angle in the range of 35 to 45 degrees to the coating surface.
3. The cut is drawn at a constant speed over about 0.5 seconds per cut so as to penetrate the coating film and reach the conductive support.
4). A cellophane adhesive tape is affixed on the grid so that the length of the adhesive portion is about 50 mm, and the tape is completely adhered to the coating film by rubbing with an eraser.
5. One to two minutes after attaching the tape, hold one end of the tape at a right angle to the coating surface and peel it off instantaneously.
6). The coated surface and the tape are observed, the number of grids peeled off at the interface between the photosensitive layer and the resin layer is determined, and the ratio of the peeled area is calculated. In the adhesion test, the photoreceptor was subjected to a cross cut test according to the method described in JIS K5400-1990, and the number of cross cuts remaining out of 100 was counted. The residual rate was calculated from the following formula and evaluated.
Residual rate Te (%) = number not removed (mass) / total number (100 mass)
In addition, evaluation was performed according to the following criteria, and ◎, ○, and Δ were regarded as acceptable.
That is,
A: 90% <Te ≦ 100%
○: 75% <Te ≦ 90%
Δ: 60% <Te ≦ 75%
X: Other than the above Evaluation results are summarized in Table 3 below.

  As is clear from the above results, the photoreceptors 1 to 35 of the present invention are excellent in any evaluation item, while the comparative photoreceptors 36 to 39 are inferior in any evaluation item. It was a thing.

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Photosensitive layer 3 Intermediate | middle layer 4 Charge generation layer 5 Charge transport layer 6 Surface protective layer 7 Surface modification metal oxide fine particle 10 Electrophotographic photoreceptor (photoreceptor)
1Y, 1M, 1C, 1Bk Photosensitive drum 2Y, 2M, 2C, 2Bk Charging unit 3Y, 3M, 3C, 3Bk Exposure unit 4Y, 4M, 4C, 4Bk Developing unit 5Y, 5M, 5C, 5Bk Primary transfer roller 6Y, 6M , 6C, 6Bk Cleaning means 10Y, 10M, 10C, 10Bk Image forming unit

Claims (6)

An electrophotographic photosensitive member in which a photosensitive layer and a surface protective layer are sequentially laminated on a conductive support, wherein the surface protective layer has a structure represented by a binder resin, a charge transport agent, and the following general formula (1) contains a surface-modified metal oxide fine particles in the hole-transporting compound having,
The electrophotographic photoreceptor , wherein the binder resin contains one of a resin obtained by polymerizing a crosslinkable polymerizable compound having an acryloyl group or a methacryloyl group, a polycarbonate resin, or a polyarylate resin .

(In general formula (1), A represents a hole transporting group. Q ₁ represents an acidic group. R ₁ represents a substituted or unsubstituted alkylene group, alkenylene group, alkynylene group or arylene group. K , when .k representing a positive integer of 1 or more represents an integer of 2 or more, R ₁ and Q ₁ may have each be the same or different.) 2. The electrophotographic photosensitive member according to claim 1, wherein the hole transporting compound having a structure represented by the general formula (1) is a compound having a structure represented by the following general formula (2). body.

(In General Formula (2), Ar ₁ represents a substituted or unsubstituted aryl group. Ar ₂ , Ar ₃ , Ar _4, and Ar ₅ may be the same or different, and each is a substituted or unsubstituted arylene. R ₂ and R ₃ may be the same or different and each represents a substituted or unsubstituted alkylene group, alkenylene, alkynylene group, or arylene group, and Q ₂ and Q ₃ are the same or different. And m, n, p and q each represents 0 or 1. When p is 0, Ar ₃ represents a substituted or unsubstituted aryl group.   The electrophotographic photosensitive member according to claim 1, wherein the charge transfer agent has a molecular weight in the range of 250 to 800.   The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the metal oxide fine particles are any one of tin oxide fine particles, titanium oxide fine particles, zinc oxide fine particles, and alumina fine particles. body. An electrophotographic image forming apparatus having at least a charging unit, an exposure unit, a developing unit, and a transfer unit for charging an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is any one of claims 1 to 4. An electrophotographic image forming apparatus, which is the electrophotographic photosensitive member according to the above. 6. A process cartridge used in the electrophotographic image forming apparatus according to claim 5 , wherein the process cartridge includes at least the electrophotographic photosensitive member according to any one of claims 1 to 4 and a charging unit. A process cartridge having at least one of an exposure unit and a development unit as a unit and configured to be able to be taken in and out of the electrophotographic image forming apparatus.

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