JP2009186984A - Electrophotographic photoreceptor, image forming apparatus and process cartridge for image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a long-life photoreceptor which is excellent in abrasion resistance, suppresses an increase in bright section potential, and also suppresses image defects such as ghost and image deletion to enhance the stability of image quality. <P>SOLUTION: In the photoreceptor, a charge transport layer 33 includes a charge transport material having a triarylamine structure, and a cross-linked charge transport layer 35 is formed by hardening a radical-polymerizable monomer having no charge transport structure and a radical-polymerizable compound having a charge transport structure. The photoreceptor satisfies relationships of equations (1) and (2). The equations (1):-0.16&le;Ip(T)-Ip(G)&le;0.07 and (2) 0.07&lt;Ip(O)-Ip(G)&le;0.33, wherein Ip(G), Ip(T) and Ip(O) represent ionization potentials of a charge generation layer 32, the charge transport layer 33 and the cross-linked charge transport layer 35, respectively. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a laser printer, and a facsimile, a process cartridge, and an electrophotographic photosensitive member used for them. Specifically, the present invention relates to an electrophotographic photoreceptor excellent in image quality stability and durability, a process cartridge for an image forming apparatus using the same, and an image forming apparatus.

In recent years, organic photoreceptors have been widely used for electrophotographic photoreceptors (hereinafter also simply referred to as photoreceptors). For organic photoreceptors, it is easy to develop materials compatible with various exposure light sources from visible light to infrared light, to select materials that are less affected by environmental pollution, and to reduce manufacturing costs. There are many advantages. However, organic photoreceptors are weaker in physical and chemical strength than inorganic photoreceptors, and wear and scratches are likely to occur due to long-term use, and significant problems remain in durability and image quality stability.
An electrophotographic image forming apparatus is generally an electrophotographic photosensitive member, a charger for charging the electrophotographic photosensitive member, and a latent image for forming an electrostatic latent image on the surface of the electrophotographic photosensitive member charged by the charger. Forming device, developing device for attaching toner to the electrostatic latent image formed by the latent image forming device, transfer means for transferring the attached toner to the transfer object, and toner remaining on the surface of the photoreceptor without being transferred It is provided with a cleaning device or the like that removes water.
In the organic photoreceptor, the surface of the photoreceptor is chemically or physically deteriorated by repeating the steps such as charging, development, transfer, and cleaning as described above, and wear is promoted or scratches are formed. As a result, the image quality deteriorates at an early stage, so that the wear resistance of the organic photoreceptor has been regarded as one of the most important issues. On the other hand, many techniques for providing a protective layer for the purpose of improving the wear resistance of the organic photoreceptor are disclosed.

For example, many techniques for improving mechanical durability by providing a protective layer on the outermost surface of the photoreceptor and dispersing inorganic fine particles in the protective layer are disclosed. As an example, Patent Document 1 proposes an electrophotographic photoreceptor in which at least a photosensitive layer and a protective layer containing a filler are sequentially formed on a conductive support.
As another means, many techniques for improving by increasing the hardness of the photoreceptor surface have been disclosed. For example, in Patent Document 2 and Patent Document 3, when a magnetic brush type is applied as a charger, magnetic particles are involuntarily transferred onto the photoconductor, and the particles are transferred to the photoconductor in the transfer unit or the cleaning unit. It has been proposed to increase the hardness of the photoconductor protective layer in order to prevent scratching due to strong pressing. Further, Patent Document 4 proposes to increase the hardness of the photoconductor in order to suppress photoconductor surface wear when the blade-type cleaning method is applied.
As specific means for increasing the surface hardness of the photoreceptor as described above, it has been proposed to use a crosslinkable material such as a thermosetting resin or a UV curable resin as a constituent component of the photoreceptor protective layer. For example, Patent Documents 5 to 7 propose methods for improving the wear resistance and scratch resistance of the protective layer by applying a thermosetting resin as a binder component of the protective layer.

Patent Documents 8 to 10 disclose a technique for improving wear resistance and scratch resistance by including a protective layer with a siloxane resin bonded with a charge transport capability-imparting group.
Further, in Patent Document 11, in order to improve wear resistance and scratch resistance, a charge transport layer is formed using a monomer having a carbon-carbon double bond, a charge transport material having a carbon-carbon double bond, and a binder resin. Techniques for making them have been reported.
Patent Document 12 describes a method for forming a charge transport layer by curing a tri- or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. Has been. Further, Patent Document 22 discloses a method of forming a protective layer in which a trifunctional or higher functional radical polymerizable monomer having no charge transporting structure and a radical polymerizable compound having a charge transporting structure are further cured and a filler is dispersed. Is described.
By using the above-described means, the wear resistance of the photoreceptor is dramatically improved. In particular, a photoconductor using a curable resin as a protective layer has a high hardness and can produce a photoconductor excellent in wear resistance and scratch resistance. Scratch resistance is greatly improved.
However, although the wear resistance and scratch resistance are remarkably improved by these techniques, the actual life as a photoreceptor is not improved as expected. This is because the provision of the protective layer increases the bright portion potential and causes image quality degradation such as image flow. In particular, an increase in the bright portion potential causes a decrease in image density. When the dark portion potential is increased to suppress the increase, the electric field strength is increased, thereby causing image defects such as background stains. Moreover, it is thought that the increase in the light portion potential leads to worsening the negative ghost. If the transfer bias polarity is opposite to the photoconductor charging polarity, and the negative ghost is charged to a polarity opposite to the photoconductor charging polarity by the transfer bias, this potential cannot be canceled by the photostatic discharge, It occurs when the history of the previous electrostatic latent image remains, and when the bright part potential rises, the history of the electrostatic latent image appears strongly, so the negative ghost is thought to deteriorate.

Therefore, in order to achieve high image quality stabilization, it is important to suppress the rise in the bright portion potential, but there are many problems associated therewith. Details are described below.
The cause of the bright portion potential increase is largely due to charge traps in the interface between the charge generation layer and the charge transport layer, the interface between the charge transport layer and the protective layer, or the bulk of the charge transport layer and the protective layer.
Among these charge trapping factors, the influence of the interface between the charge generation layer and the charge transport layer and the interface between the charge transport layer and the protective layer is particularly great. Therefore, as one means for reducing the bright portion potential, a material having a smaller ionization potential is used for the charge transport material contained in the charge transport layer, and the charge injection barrier from the charge generation layer to the charge transport layer can be reduced. Can be mentioned. As an example of these known techniques, Patent Document 13 and the like are disclosed, which is an effective method for reducing the light portion potential.
In particular, since titanyl phthalocyanine pigments have a low ionization potential, a charge transport material having an ionization potential equal to or lower than that of titanyl phthalocyanine is used to reduce the light potential in a photoreceptor using the same as a charge generation material. Must be contained in the charge transport layer.

On the other hand, as another means for reducing the bright portion potential, it is disclosed that it is effective to reduce the charge injection barrier from the charge transport layer to the protective layer. For example, as described in Patent Document 14, the charge transporting material contained in the protective layer has a lower ionization potential than the charge transporting material contained in the photosensitive layer, so that the photosensitive layer / protective layer interface has a lower ionization potential. It is effective to improve the charge injection property. Further, as described in Patent Document 15, the ionization potential values of the charge generation material and the charge transport material are in an optimum relationship, and the ionization potential of the charge transport material in the protective layer is set to the ionization potential of the charge transport material in the charge transport layer. By making the following, an increase in the residual potential can be suppressed. As described above, it is known that the light-portion potential can be reduced by giving the charge transport material contained in the protective layer a lower ionization potential than the charge transport material contained in the charge transport layer. .
Moreover, the effect which can suppress generation | occurrence | production of a ghost can be acquired by reducing the electric charge injection barrier from a charge transport layer to a protective layer. For example, Patent Document 16 describes that ghosting can be suppressed by reducing the difference in ionization potential between the photosensitive layer and the protective layer. Japanese Patent Application Laid-Open No. H10-228561 describes that the increase in bright portion potential can be suppressed by reducing the difference in oxidation potential between the charge transport material of the photosensitive layer and the charge transport material of the protective layer.

Therefore, in order to achieve high image quality by reducing the bright part potential of the photoreceptor and suppressing ghosts based on the conventionally known technology, the charge transport layer has an ionization potential equal to or lower than that of the charge generation material. This can be achieved by containing a charge transport material and further including a charge transport material having an ionization potential equal to or lower than that of the charge transport material contained in the charge transport layer in the protective layer.
However, when a phthalocyanine pigment having a small ionization potential is used as the charge generation material, the ionization potential of the charge transport material contained in the layer formed on the outermost surface of the photoreceptor is inevitably low. A new problem occurs that causes image flow. As described above, the surface of the photoreceptor is easily deteriorated by repeating processes such as charging, development, and cleaning. In particular, it is believed that when exposed to an oxidizing gas such as ozone generated by charging, the charge transport material contained on the surface of the photoreceptor is altered and the resistance is lowered. A charge transport material having a smaller ionization potential has a greater effect, and thus an image stream is generated by repeated use of the photoreceptor.

Patent Document 18 discloses a technique that defines the ionization potential difference between the photosensitive layer and the curable resin layer and the time response of the photoreceptor. This patent document describes that a good dot image can be formed even under high temperature and high humidity and low temperature and low humidity. Further, Y-type titanyl phthalocyanine is exemplified as the charge generation material of the examples. However, the ionization potential of the charge transport layer used in the examples is considerably larger than the ionization potential of the charge generation layer. That is, although an effect of suppressing the image flow can be obtained, it is difficult to reduce the bright part potential, and it is considered to be based on the sacrifice. In the comparative example, a charge transport layer having an ionization potential smaller than that of titanyl phthalocyanine is exemplified, but it is apparent that the chargeability is significantly deteriorated because it is much smaller than the ionization potential of the protective layer.
Also in Patent Document 15, it is considered that the effect of suppressing the increase in residual potential is high by setting the ionization potential of the charge transport material in the protective layer to be equal to or lower than the ion transport potential of the charge transport material in the charge transport layer. If a charge transport material having a small ionization potential is included in the protective layer located on the body surface, it is considered that the problem of image flow occurs as described above. However, in the example of Patent Document 15, only the result of EPA for evaluating electrostatic characteristics is described, and the image is not confirmed. Even if the increase in the residual potential can be suppressed, the function as a photoconductor cannot be exhibited if an image flow occurs in an oxidizing gas atmosphere, and a fundamental solution has not been reached.

As described above, the reduction of the bright part potential and the suppression of the bright part potential increase due to repeated use can be achieved by a conventionally known technique. However, when a metal phthalocyanine pigment having high sensitivity is used for the charge generation material, Since these generally have a low ionization potential, it is necessary to further reduce the ionization potential of the charge transport material contained in the charge transport layer or the protective layer in order to suppress the bright part potential rise. Even if it can be suppressed, new problems such as image flow are caused. For this reason, it is difficult to achieve both reduction of the bright area potential and high stabilization of the image quality in the photoreceptor using the metal phthalocyanine pigment, which is particularly advantageous in terms of sensitivity characteristics. Regardless, the reality is that high durability of the photoreceptor has not been realized.
On the other hand, a method for stabilizing the image quality by adding an additive to the photosensitive layer or the cross-linked surface layer is known. For stabilizing the image quality, it is effective to contain an antioxidant in the photosensitive layer. However, when such an additive having only an antioxidant ability is used, its characteristic expression depends on the amount of antioxidant added, so that a considerable amount of addition is necessary to obtain a sufficient effect. May be. However, when the antioxidant does not have charge transportability, the charge transportability tends to decrease in proportion to the amount added, and as a result, the bright part potential may increase.
In particular, when the ionization potential difference among the charge generation layer, the charge transport layer, and the protective layer is large and the injection barrier is large, the bright portion potential is likely to increase.
Patent Documents 19 to 21 describe a method for improving the image quality by adding an antioxidant having a charge transport function to the photosensitive layer or the cross-linked surface layer. Such an additive is effective in stabilizing the image quality. However, since the charge transport materials of the charge transport layers described in Patent Documents 19 to 21 have a large ionization potential, when combined with a metal phthalocyanine having a small ionization potential, the difference in ionization potential is widened, and the light portion potential of the photoreceptor is likely to increase. .
Patent Documents 23 to 27 describe a method of stabilizing electrophotographic characteristics by combining a distyryl compound and an antioxidant. However, the evaluation result is limited only to the electrical characteristics, and no image is output. When a distyryl compound having a low ionization potential is on the outermost surface, intense image flow may occur after exposure to NOx. Since it is often impossible to determine whether or not there is an image flow only by electrical characteristics, there is a possibility that the image quality cannot be sufficiently stabilized by the methods described in Patent Documents 23 to 27.
In this way, it is extremely difficult to design an electrophotographic photosensitive member that suppresses the rise in bright area potential and satisfies both excellent abrasion resistance and high image quality stabilization. At present, the photoconductor must be designed.

JP 2002-139659 A JP 2001-125286 A JP 2001-324857 A JP 2003-098708 A JP-A-5-181299 Japanese Patent Laid-Open No. 2002-006526 JP 2002-082465 A JP 2000-284514 A JP 2000-284515 A JP 2001-194413 A Japanese Patent No. 3194392 JP 2004-302451 A JP 2007-072139 A JP 2002-207308 A JP 2000-292959 A JP 2003-186222 A JP-A-4-28459 Japanese Patent Laid-Open No. 2001-255585 JP 2007-279678 A JP 2007-272191 A JP 2007-272192 A JP 2005-99688 A JP 2000-24208 A Japanese Patent Laid-Open No. 11-352710 JP-A-8-082941 Japanese Patent No. 3287126 Japanese Patent Application Laid-Open No. 07-244389

  Therefore, the present invention has been made in view of the above-described problems of the prior art, and has excellent wear resistance, suppresses bright area potential rise, and has image defects such as negative ghost, image flow, and background stains. It is an object of the present invention to provide a long-life photoconductor that is suppressed to improve image quality stability.

The features of the present invention, which is a means for solving the above problems, are listed below.
The above problems are solved by the following (1) to (19) of the present invention.
(1) In an electrophotographic photosensitive member in which at least a charge generation layer, a charge transport layer, and a crosslinkable charge transport layer are sequentially laminated on a conductive support, a metal phthalocyanine pigment as at least a charge generation material is included in the charge generation layer. The charge transport layer contains at least a charge transport material having a triarylamine structure, and the crosslinked charge transport layer comprises a radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a charge transport structure. When the ionization potential of the charge generation layer is Ip (G), the ionization potential of the charge transport layer is Ip (T), and the ionization potential of the cross-linked charge transport layer is Ip (O) An electrophotographic photoreceptor, wherein the following formula (1) and the following formula (2) are satisfied.
−0.16 ≦ Ip (T) −Ip (G) ≦ 0.07 (1)
0.07 <Ip (O) −Ip (G) ≦ 0.33 (2)
(2) The functional group of the radical polymerizable monomer having no charge transporting structure and / or the functional group of the radical polymerizable compound having the charge transporting structure is an acryloyloxy group and / or a methacryloyloxy group. The electrophotographic photosensitive member according to (1), which is characterized.
(3) The radical polymerizable monomer having no charge transporting structure has 3 or more functional groups, and the ratio of molecular weight to the number of functional groups (molecular weight / functional group number) is 250 or less (1) The electrophotographic photosensitive member according to (2).
(4) The electrophotographic photosensitive member according to any one of (1) to (3), wherein a charge transporting structure of the radical polymerizable compound having the charge transporting structure is a triarylamine structure.
(5) Any one of (1) to (4), wherein the radical polymerizable compound having a charge transporting structure is at least one compound represented by the following general formula (1) or (2): The electrophotographic photoreceptor described in 1.
(In the formula, R ₄₀ represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a cyano group, a nitro group, A group, an alkoxy group, —COOR ₄₁ (R ₄₁ represents a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or an aryl group which may have a substituent. ), A carbonyl halide group or CONR ₄₂ R ₄₃ (R ₄₂ and R ₄₃ have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Represents an aryl group which may be the same or different from each other. Ar ₂ and Ar ₃ represent a substituted or unsubstituted arylene group and may be the same or different. A r ₄ and Ar _{5 each} represents a substituted or unsubstituted aryl group, which may be the same or different, and X is a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, substituted or unsubstituted Represents an unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group, Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group, or an alkyleneoxycarbonyl group, and m and n are 0 to 0. Represents an integer of 3.)
(6) The electrophotographic photosensitive member according to any one of (1) to (5), wherein the charge transport material having a triarylamine structure contained in the charge transport layer is a distyryl compound.
(7) The electrophotographic photoreceptor according to (6), wherein the distyryl compound having a triarylamine structure is a distyrylbenzene derivative represented by the general formula (3) having the following structure.
[In the above formula, R _{1 to} R ₃₀ are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkyl group having 1 to 4 carbon atoms. It represents an aryl group substituted with an alkoxy group, and may be the same or different. ]

(8) The electrophotography according to (7), wherein at least one of R ₃ , R ₈ , R ₁₉ and R ₂₄ of the distyrylbenzene derivative represented by the general formula (3) is a methyl group Photoconductor.
(9) The electrophotographic photosensitive member according to any one of (1) to (8), wherein the crosslinkable charge transport layer contains a filler.
(10) The electrophotographic photosensitive member according to any one of (1) to (9), wherein the charge transport layer contains an antioxidant.
(11) The charge transport layer contains a charge transport material having a triarylamine structure and a compound represented by the following general formula (4), according to any one of (1) to (10) Electrophotographic photoreceptor.
(In the formula, R ₉₂ and R ₉₃ represent an aromatic ring group-substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, which may be the same or different. R ₉₂ and R ₉₃ are bonded to each other to form a nitrogen atom. And j and k each represent an integer of 0 to 3. However, j and k are not simultaneously 0. R ₉₄ and R ₉₅ are hydrogen atoms, substituted or unsubstituted. Represents an alkyl group having 1 to 11 carbon atoms and a substituted or unsubstituted aromatic ring group, which may be the same or different, and Ar ₅₁ and Ar ₅₂ each represent a substituted or unsubstituted aromatic ring group and are the same But it may be different.)
(12) The charge transport layer contains a charge transport material having a triarylamine structure and a compound represented by the following general formula (5-1): (1) to (10) The electrophotographic photoreceptor described
(In the formula, R ₉₆ and R ₉₇ represent a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted alkyl group, and may be the same or different. R ₉₆ and R ₉₇ are bonded to each other. And a heterocyclic group containing a nitrogen atom may be formed, Ar ₅₃ and Ar ₅₄ each represent a substituted or unsubstituted aromatic ring group, and p and q each represents an integer of 0 to 3, provided that p and q Are not simultaneously 0. r represents an integer of 1 to 3.)
(13) The charge transport layer contains a charge transport material having a triarylamine structure and a compound represented by the following general formula (5-2): (1) to (10) The electrophotographic photoreceptor described
(Wherein R ₉₈ and R ₉₉ represent a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted alkyl group, and may be the same or different. R ₉₈ and R ₉₉ are bonded to each other. And a heterocyclic group containing a nitrogen atom, Ar ₅₅ and Ar ₅₆ each represents a substituted or unsubstituted aromatic ring group, and s and t each represents an integer of 0 to 3, provided that s and t Are not simultaneously 0. u represents an integer of 1 to 3.)
(14) The charge transport layer contains a charge transport material having a triarylamine structure and a compound represented by the following general formula (6), according to any one of (1) to (10) Electrophotographic photoreceptor
(Wherein R ₁₀₁ and R ₁₀₂ represent a substituted or unsubstituted alkyl group or a substituted or unsubstituted aromatic ring group, and may be the same or different. However, any one of R ₁₀₁ and R ₁₀₂ may be used. Is a substituted or unsubstituted aromatic ring group, and R ₁₀₁ and R ₁₀₂ may be bonded to each other to form a substituted or unsubstituted heterocyclic group containing a nitrogen atom, and Ar ₅₇ is a substituted or unsubstituted group. Represents an aromatic ring group of
(15) The thickness T1 of the charge transport layer and the thickness T2 of the cross-linked charge transport layer satisfy the relationship of the following formula (3): (1) Any one of (1) to (14) The electrophotographic photosensitive member described.
T1> T2 × 2 Formula (3)

(16) In an image forming apparatus comprising at least a charging unit, an exposure unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member, the electrophotographic photosensitive member according to any one of (1) to (15) An image forming apparatus comprising an electrophotographic photosensitive member.
(17) A plurality of image forming elements including at least a charging unit, an exposure unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member are arranged, and the electrophotographic photosensitive member is any one of (1) to (15). An image forming apparatus comprising an electrophotographic photosensitive member.
(18) A cartridge in which an electrophotographic photosensitive member and at least one means selected from a charging means, an exposure means, a developing means, a transfer means, and a cleaning means are integrated, and the cartridge is attached to and detached from the apparatus main body. The image forming apparatus according to any one of (16) to (17), wherein the image forming apparatus is free.
(19) In a cartridge in which an electrophotographic photosensitive member is integrated with at least one means selected from a charging unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit, the electrophotographic photosensitive unit is (1) to ( 15) A process cartridge for an image forming apparatus, which is the electrophotographic photosensitive member according to any one of 15).

The electrophotographic photosensitive member of the present invention is excellent in abrasion resistance and scratch resistance due to the provision of a cross-linked charge transport layer on the surface, has a low bright part potential, and is stable with little increase in bright part potential even after repeated use. In addition, by suppressing image defects such as ghost and image flow, an electrophotographic photosensitive member, an image forming apparatus, and a process cartridge for the image forming apparatus that can stably output high image quality even when used repeatedly over a long period of time Can provide.
According to the photoreceptor of the present invention, a metal phthalocyanine pigment having a small ionization potential and high sensitivity is used as the charge generation material, and the difference in ionization potential between the charge transport layer and the charge generation layer is −0. A charge transport material containing 16 or more and 0.07 or less is contained, and the charge transport material itself is crosslinked on the surface to form a crosslinked charge transport layer, and the ionization potential of the crosslinked charge transport layer and the charge generation layer is By providing a cross-linkable charge transport layer with a difference of greater than 0.07 and less than or equal to 0.33, the bright portion potential rise is suppressed and the occurrence of image flow and ghosts is suppressed. It was realized to solve the problem. As a result, high-quality images can be output stably even when used repeatedly over a long period of time, and high sensitivity and suppression of bright area potential rise have enabled high-quality images and high life even in high-speed image forming devices. Realization of compatibility was realized.

  In the present invention, the reason why the increase in the bright part potential can be suppressed even when the ionization potential of the cross-linked charge transport layer is higher than the ionization potential of the charge transport layer is described below. Unlike Japanese Unexamined Patent Publication No. 2000-292959 in which is cured, it is presumed that it was a cross-linked charge transport layer in which the charge transport material itself contained in the protective layer was cross-linked. It is also considered that one of the reasons is that the thickness of the cross-linked charge transport layer is smaller than that of the charge transport layer. Further, when a cross-linked charge transport layer cured with a radical polymerizable compound having an acryloyloxy group and / or a methacryloyloxy group is used, or when a distyrylbenzene derivative is used as a charge transport material in the charge transport layer, It has been found that this effect is enhanced, and it is particularly effective in obtaining the effect of the present invention that simultaneously realizes the suppression of the bright portion potential rise and the suppression of image flow and ghost.

The image forming apparatus of the present invention will be described in detail below with reference to the drawings.
<< Configuration of electrophotographic photoreceptor >>
As shown in FIG. 1, the photoreceptor of this embodiment has at least a charge generation layer 32, a charge transport layer 33, and a cross-linked charge transport layer 35 in this order on a conductive support 31. It is a type.

<About conductive support>
Examples of the conductive support include those having a volume resistance of 10 ¹⁰ Ω · cm or less, such as metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, and platinum, tin oxide, and indium oxide. After metal oxide is deposited or sputtered, film or cylindrical plastic, paper coated, or aluminum, aluminum alloy, nickel, stainless steel, etc. Pipes that have been subjected to surface treatment such as cutting, super-finishing, and polishing can be used. Further, endless nickel belts and endless stainless steel belts disclosed in JP-A-52-36016 can also be used as the conductive support.
In addition, the conductive support dispersed in an appropriate binder resin on the support can be used as the conductive support of the present invention. Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc and silver, or metal oxide powder such as conductive tin oxide and ITO. Can be mentioned.

The binder resin used at the same time includes polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine Examples thereof include thermoplastic resins such as resins, urethane resins, phenol resins, and alkyd resins, thermally crosslinkable resins, and photocrosslinkable resins. Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.
Furthermore, a heat-shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, polytetrafluoroethylene-based fluororesin on a suitable cylindrical substrate. Those provided with a conductive layer can be used favorably as the conductive support of the present invention.

<< About photosensitive layer >>
Next, the charge generation layer and the charge transport layer will be described.
<About the charge generation layer>
The charge generation layer is a layer mainly composed of a charge generation material having a charge generation function, and a binder resin can be used in combination as necessary. A metal phthalocyanine pigment is used as the charge generating material of the present invention.
Examples of the metal phthalocyanine pigment include metal phthalocyanines represented by the following general formula (7). These charge generation materials can be used alone or as a mixture of two or more.
(In the formula, M (central metal) represents a metal element. M (central metal) mentioned here is Li, Be, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr. , Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Ba, Hf, Ta, W , Re, Os, Ir, Pt, Au, Hg, TI, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, Pa, U , Np, Am, etc., or two or more elements such as oxide, chloride, fluoride, hydroxide, bromide, etc. The central metal is not limited to these elements.)

The metal phthalocyanine-based charge generation material in the present invention may have a basic skeleton as represented by the general formula (7) as an example, and has a multimeric structure such as a dimer and a trimer. It may have a higher order polymer structure. In addition, the basic skeleton may have various substituents. Of these various metal phthalocyanines, titanyl phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, etc. having TiO as the central metal are particularly preferred in terms of photoreceptor characteristics. In addition, these metal phthalocyanines are known to have various crystal systems. For example, in the case of titanyl phthalocyanine, α, β, γ, m, Y type, etc., in the case of copper phthalocyanine, α, β, γ, etc. It has a polycrystal system of Even in a metal phthalocyanine having the same central metal, various properties change as the crystal system changes. It has been reported that the characteristics of a photoreceptor using these metal phthalocyanine pigments having various crystal systems also change accordingly (Electrophotographic Society Vol. 29, No. 4 (1990)). For this reason, selection of the crystal system of metal phthalocyanine is very important in terms of photoreceptor characteristics.
Among these metal phthalocyanine pigments, titanyl phthalocyanine pigments are effectively used, and in particular, at least 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (1.542 °) of CuKα. The titanyl phthalocyanine crystal having the maximum diffraction peak has a particularly high sensitivity, and can be used particularly effectively in the present invention because the speed of image formation can be increased. Further, among them, it has a maximum diffraction peak at 27.2 °, and further has main peaks at 9.4 °, 9.6 °, and 24.0 °, and is 7.3 as the lowest diffraction peak. A titanyl phthalocyanine crystal having a peak at ゜, no peak between the 7.3 ° peak and the 9.4 ° peak, and no peak at 26.3 ° has a charge generation efficiency. It can be used very effectively as a charge generating material of the present invention, such as being large, having good electrostatic properties, and being less likely to cause scumming. These charge generation materials can be used alone or as a mixture of two or more.

As a binder resin used as necessary for the charge generation layer, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, Examples include polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, and polyvinyl pyrrolidone. These binder resins can be used alone or as a mixture of two or more. The amount of the binder resin is preferably 0 to 5 parts by weight, more preferably 10 to 3 parts by weight with respect to 1 part by weight of the charge generating material. The binder resin may be added before or after dispersion.
Moreover, as a solvent to be used, generally used organic materials such as isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin, etc. Among them, a ketone solvent, an ester solvent, and an ether solvent are preferable. These may be used alone or in combination of two or more.

The charge generation layer is obtained by dispersing the charge generation material in a solvent using a known dispersion method such as a ball mill, an attritor, a sand mill, a bead mill, or an ultrasonic wave together with a binder resin as necessary. Can do. The binder resin may be added before or after the charge generating material is dispersed. The coating solution for the charge generation layer is mainly composed of a charge generation material, a solvent, and a binder resin, and it contains additives such as a sensitizer, a dispersant, a surfactant, and silicone oil. May be. In some cases, it is also possible to add a charge transport material described later to the charge generation layer. The addition amount of the binder resin is usually 0 to 500 parts by weight, preferably 10 to 300 parts by weight with respect to 100 parts by weight of the charge generation material.
The charge generation layer is formed by coating on a conductive support or an undercoat layer using the coating solution and drying. As the coating method, known methods such as dip coating, spray coating, bead coating, nozzle coating, spinner coating, ring coating, and the like can be used. The thickness of the charge generation layer is usually about 0.01 to 5 μm, preferably 0.1 to 2 μm. Further, drying after coating is performed by heating using an oven or the like. The drying temperature of the charge generation layer is preferably 50 to 160 ° C, more preferably 80 to 140 ° C.

<About the charge transport layer>
The charge transport layer is a layer having a charge transport function, and is a layer mainly composed of a charge transport material and a binder resin. In the present invention, the charge transport layer must contain at least a charge transport material having a triarylamine structure, but may contain an electron transport material and a hole transport material as necessary. Examples of each are shown below. The charge transport material means an electron transport material and a hole transport material.
Examples of the electron transporting substance include chloroanil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4, 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide, diphenoquinone derivatives and naphthalenetetracarboxylic acid diimide derivatives. These electron transport materials can be used alone or as a mixture of two or more.
Examples of hole transport materials include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazoline derivatives, divinylbenzene derivatives, hydrazone derivatives And other known materials such as indene derivatives, butadiene derivatives, pyrene derivatives, distyryl derivatives, enamine derivatives, and the like. These hole transport materials may be used alone or in combination of two or more.
Among charge transport materials having a triarylamine structure contained in the charge transport layer, distyryl derivatives are effectively used in the present invention. A distyryl derivative refers to a material having two styryl groups. These materials have large π conjugation and high mobility, so that charge transfer is likely to occur. As a result, it is considered that there is an effect of suppressing an increase in the bright portion potential as compared with a charge transport material having an equivalent ionization potential.
Further, among the distyryl derivatives, the distyrylbenzene derivative represented by the general formula (3) is particularly preferable. The distyrylbenzene derivative represented by the general formula (3) has a plurality of triarylamine structures having a high charge transport function, and also has a large π conjugation via an aromatic ring group at the center of the structural formula. In addition, since the molecular skeleton is large and the triarylamine structures are separated from each other, charge transfer is likely to occur between molecules.
The distyrylbenzene derivative of the present invention can be synthesized by a known method such as Japanese Patent No. 2552695.

An example of the distyryl compound is given below. However, the present invention is not limited to these compounds.

Below, an example of the distyrylbenzene derivative represented by General formula (3) effective in this invention is given. However, the present invention is not limited to these compounds.

Among the above-mentioned distyrylbenzene derivatives, those in which at least one of R ₃ , R ₈ , R _19, and R _{24 in} the general formula (3) is a methyl group are particularly effective for reducing the light portion potential.

Binder resins include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, poly Vinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, Examples thereof include thermoplastic or thermosetting resins such as phenol resins and alkyd resins.
In addition, as a binder resin, a polymer charge transport material having a charge transport function, for example, a polycarbonate, polyester, polyurethane, polyether, or polyamine having an arylamine skeleton, a benzidine skeleton, a hydrazone skeleton, a carbazole skeleton, a stilbene skeleton, a pyrazoline skeleton, or the like. Polymer materials such as siloxane and acrylic resins, polymer materials having a polysilane skeleton, and the like can be used and are useful.

As the polymer charge transporting material, known materials can be used, and in particular, a polycarbonate containing a triarylamine structure in the main chain and / or side chain is preferably used. Among these, the polymer charge transport materials represented by the formulas (I) to (X) are favorably used, and these are exemplified below and specific examples are shown.
Wherein R ₅₁ , R ₅₂ and R ₅₃ are each independently a substituted or unsubstituted alkyl group or a halogen atom, R ₅₄ is a hydrogen atom or a substituted or unsubstituted alkyl group, and R ₅₅ and R ₅₆ are substituted or Unsubstituted aryl group, o, p and q are each independently an integer of 0 to 4, k and j represent a composition, 0.1 ≦ k ≦ 1, 0 ≦ j ≦ 0.9, and n is a repeating unit The number is an integer of 5 to 5000. X represents an aliphatic divalent group, a cycloaliphatic divalent group, or a divalent group represented by the following general formula. (One copolymer species is described in the form of an alternating copolymer, but it may be a random copolymer.)

(R ₁₀₁ and R ₁₀₂ each independently represents a substituted or unsubstituted alkyl group, an aryl group or a halogen atom. L and m are integers of 0 to 4, Y is a single bond, and a straight chain having 1 to 12 carbon atoms. Chain, branched or cyclic alkylene group, —O—, —S—, —SO—, —SO ₂ —, —CO—, —CO—O—Z—O—CO— (wherein Z is aliphatic) Represents a divalent group of

Or
a represents an integer of 1 to 20, b represents an integer of 1 to 2000, and R ₁₀₃ and R ₁₀₄ represent a substituted or unsubstituted alkyl group or aryl group. Here, R ₁₀₁ and R ₁₀₂ , and R ₁₀₃ and R ₁₀₄ may be the same or different.

In the formula, R ₅₇ and R ₅₈ represent a substituted or unsubstituted aryl group, and Ar ₁₁ , Ar ₁₂ , and Ar ₁₃ represent the same or different arylene groups. X, k, j, and n are the same as in the formula (I). In the formula (II), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

In the formula, R ₅₉ and R ₆₀ represent a substituted or unsubstituted aryl group, and Ar ₁₄ , Ar ₁₅ , and Ar ₁₆ represent the same or different arylene groups. X, k, j, and n are the same as in the formula (I). In the formula (III), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

In the formula, R ₆₁ and R ₆₂ are substituted or unsubstituted aryl groups, Ar ₁₇ , Ar ₁₈ and Ar ₁₉ are the same or different arylene groups, and p represents an integer of 1 to 5. X, k, j, and n are the same as in the formula (I). In the formula (IV), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

In the formula, R ₆₃ and R ₆₄ are substituted or unsubstituted aryl groups, Ar ₂₀ , Ar ₂₁ , and Ar ₂₂ are the same or different arylene groups, X ₁ , X ₂
Represents a substituted or unsubstituted ethylene group or a substituted or unsubstituted vinylene group. X, k, j, and n are the same as in the formula (I). In the formula (V), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

In the formula, R ₆₅ , R ₆₆ , R ₆₇ , R ₆₈ are substituted or unsubstituted aryl groups, Ar ₂₃ , Ar ₂₄ , Ar ₂₅ , Ar ₂₆ are the same or different arylene groups, Y ₁ , Y ₂ , Y ₃ are A single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group may be the same or different. X, k, j and n are the same as in the case of the formula (VI). In the formula (VI), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

In the formula, R ₆₉ and R ₇₀ represent a hydrogen atom or a substituted or unsubstituted aryl group, and R ₆₉ and R ₇₀ may form a ring. Ar ₂₇ , Ar ₂₈ , Ar ₂₉
Represent the same or different arylene groups. X, k, j, and n are the same as in the formula (I). In the formula (VII), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

In the formula, R ₇₁ represents a substituted or unsubstituted aryl group, Ar ₃₀ , Ar ₃₁ , Ar ₃₂ , Ar _33.
Represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I). In the formula (VIII), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

In the formula, R ₇₂ , R ₇₃ , R ₇₄ , and R ₇₅ represent a substituted or unsubstituted aryl group, and Ar ₃₄ , Ar ₃₅ , Ar ₃₆ , Ar ₃₇ , and Ar ₃₈ represent the same or different arylene groups. X, k, j, and n are the same as in the formula (I). In the formula (IX), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

In the formula, R ₇₆ and R ₇₇ represent a substituted or unsubstituted aryl group, and Ar ₃₉ , Ar ₄₀ , and Ar ₄₁ represent the same or different arylene groups. X, k, j, and n are the same as in the formula (I). In the formula (X), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

The amount of the charge transport material is preferably 20 to 300 parts by weight, more preferably 40 to 150 parts by weight with respect to 100 parts by weight of the binder resin. However, when a polymer charge transport material is used, it may be used alone or in combination with a binder resin.
As the solvent used here, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used. These may be used alone or in combination of two or more.
If necessary, a plasticizer and a leveling agent can be added. As the plasticizer used in the charge transport layer, those used as general plasticizers such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is 0 to 30 weights with respect to 100 parts by weight of the binder resin. Part is appropriate. Examples of leveling agents that can be used in the charge transport layer include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain. About 0 to 1 part by weight is appropriate for the part by weight.
The thickness of the charge transport layer is preferably 30 μm or less, more preferably 25 μm or less, from the viewpoint of resolution and responsiveness. Regarding the lower limit, although it differs depending on the system to be used (particularly the charging potential), it is preferably 5 μm or more.

The electrophotographic photoreceptor of the present invention is represented by the compound represented by the general formula (4), the compound represented by the general formula (5-1), and the general formula (5-2) in the charge transport layer. The image quality stability is improved by containing at least one of the compound represented by formula (6) and the compound represented by formula (6). Furthermore, image quality stability is further improved by combining these compounds with an antioxidant. Each will be described below.
The compound represented by the above general formula (4), the compound represented by the above general formula (5-1), the compound represented by the above general formula (5-2), and the above general formula (6) in the charge transport layer. Is effective for stabilizing the image quality when the photoreceptor is used repeatedly. The reason for this is not clarified at the present time, but the alkylamino group contained in the chemical structure is a strongly basic group. A neutralizing effect on the substance is presumed. In addition, it is known that the aromatic hydrocarbon ring group-substituted amino group is a functional group having excellent charge transporting ability [Takahashi et al., Electrophotographic Society, Vol. 25, No. 3, page 16, 1986], Since the diamine compound used for this invention contains this group, it turns out that it is a compound with high charge transport ability. Furthermore, it has also been found that high sensitivity and repeat stability are further increased by using in combination with other charge transport materials.
Examples of the compound represented by the general formula (4) include compounds represented by the following general formulas (4-1) to (4-5).

(In the formula, R ₉₂ and R ₉₃ represent an aromatic ring group-substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, which may be the same or different. R ₉₂ and R ₉₃ are bonded to each other to form a nitrogen atom. And j and k each represent an integer of 0 to 3. However, j and k are not simultaneously 0. R ₉₄ and R ₉₅ are hydrogen atoms, substituted or unsubstituted. Represents an alkyl group having 1 to 11 carbon atoms and a substituted or unsubstituted aromatic ring group, which may be the same or different, and Ar ₅₁ and Ar ₅₂ each represent a substituted or unsubstituted aromatic ring group and are the same But it may be different.)

(In the formula, R ₉₂ and R ₉₃ represent an aromatic ring group-substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, which may be the same or different. R ₉₂ and R ₉₃ are bonded to each other to form a nitrogen atom. And j and k each represent an integer of 0 to 3. However, j and k are not simultaneously 0. R ₉₄ is a hydrogen atom, substituted or unsubstituted carbon number 1 Represents an alkyl group of ˜11 or a substituted or unsubstituted aromatic ring group, and Ar ₅₁ , Ar ₅₂ , Ar ₅₃ , Ar ₅₄ and Ar ₅₅ represent a substituted or unsubstituted aromatic ring group, and may be the same or different. Ar ₅₄ , Ar ₅₅ , or Ar ₅₄ , Ar ₅₃ may jointly form a heterocyclic group containing a nitrogen atom.)

(In the formula, R ₉₂ and R ₉₃ represent an aromatic ring group-substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, which may be the same or different. R ₉₂ and R ₉₃ are bonded to each other to form a nitrogen atom. And j and k each represent an integer of 0 to 3. However, j and k are not simultaneously 0. Ar ₅₁ , Ar ₅₂ , Ar ₅₃ , Ar ₅₄ and Ar ₅₅ represents a substituted or unsubstituted aromatic ring group, which may be the same or different, and Ar ₅₄ , Ar ₅₅ , or Ar ₅₄ , Ar ₅₃ jointly form a heterocyclic group containing a nitrogen atom. May be good.)
(In the formula, R ₉₂ and R ₉₃ represent an aromatic ring group-substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, which may be the same or different. R ₉₂ and R ₉₃ are bonded to each other to form a nitrogen atom. J represents an integer of 1 to 3. Ar ₅₁ , Ar ₅₂ , Ar ₅₃ , Ar ₅₄ and Ar ₅₅ represent a substituted or unsubstituted aromatic ring group, and are the same. Alternatively, Ar ₅₄ , Ar ₅₅ , or Ar ₅₄ , Ar ₅₃ may jointly form a heterocyclic group containing a nitrogen atom.)

In the general formulas (4-1) to (4-4), specific examples of the alkyl group for R ₉₂ and R ₉₃ include a methyl group, an ethyl group, a propyl group, and a butyl group. The aromatic ring groups of R ₉₂ , R ₉₃ and Ar _{51 to} Ar ₅₅ include monovalent to hexavalent aromatic hydrocarbon groups of aromatic hydrocarbon rings such as benzene, naphthalene, anthracene and pyrene, and pyridine and quinoline. Monovalent to hexavalent aromatic heterocyclic groups such as thiophene, furan, oxazole, oxadiazole, carbazole and the like. These substituents include those exemplified in the above specific examples of alkyl groups, alkoxy groups such as methoxy group, ethoxy group, propoxy group and butoxy group, or halogen atoms of fluorine atom, chlorine atom, bromine atom and iodine atom. An atom, an aromatic ring group, etc. are mentioned. Furthermore, specific examples of the heterocyclic group in which R ₉₂ and R ₉₃ are bonded to each other and contain a nitrogen atom include a pyrrolidinyl group, a piperidinyl group, and a pyrrolinyl group. In addition, examples of the heterocyclic group jointly containing a nitrogen atom include aromatic heterocyclic groups such as N-methylcarbazole, N-ethylcarbazole, N-phenylcarbazole, indole, and quinoline.
Specific examples of the structures of the compounds represented by the general formulas (4-1) to (4-4) are shown below. However, the present invention is not limited to these compounds.

The compound used for the charge transport layer is represented by the following general formula (5-1) and the following general formula (5-2).

(In the formula, R ₉₆ and R ₉₇ represent a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted alkyl group, and may be the same or different. R ₉₆ and R ₉₇ are bonded to each other. And a heterocyclic group containing a nitrogen atom may be formed, Ar ₅₃ and Ar ₅₄ each represent a substituted or unsubstituted aromatic ring group, and p and q each represents an integer of 0 to 3, provided that p and q Are not simultaneously 0. r represents an integer of 1 to 3.)
(Wherein R ₉₈ and R ₉₉ represent a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted alkyl group, and may be the same or different. R ₉₈ and R ₉₉ are bonded to each other. And a heterocyclic group containing a nitrogen atom, Ar ₅₅ and Ar ₅₆ each represents a substituted or unsubstituted aromatic ring group, and s and t each represents an integer of 0 to 3, provided that s and t Are not simultaneously 0. u represents an integer of 1 to 3.)

In these general formulas (5-1) and (5-2), specific examples of the aromatic hydrocarbon group represented by R _{96 to} R ₉₉ include aromatic hydrocarbons such as benzene, naphthalene, anthracene, and pyrene. Examples of the alkyl group represented by R _{96 to} R ₉₉ can include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, and an undecanyl group. An alkyl group having 1 to 4 carbon atoms is preferred. Examples of the aromatic ring group represented by Ar _{53 to} Ar ₅₆ include monovalent to tetravalent aromatic hydrocarbon groups of aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and pyrene, and pyridine, quinoline, and thiophene. , Furan, oxazole, oxadiazole, carbazole and the like, and monovalent to tetravalent aromatic heterocyclic groups of aromatic heterocyclic rings. These substituents include those exemplified in the above specific examples of alkyl groups, alkoxy groups such as methoxy group, ethoxy group, propoxy group and butoxy group, or halogen atoms of fluorine atom, chlorine atom, bromine atom and iodine atom. An atom, an aromatic ring group, etc. are mentioned. Furthermore, specific examples of the heterocyclic group in which R ₉₆ and R ₉₇ , or R ₉₈ and R ₉₉ are bonded to each other and contain a nitrogen atom include a pyrrolidinyl group, a piperidinyl group, and a pyrrolinyl group. In addition, examples of the heterocyclic group jointly containing a nitrogen atom include aromatic heterocyclic groups such as N-methylcarbazole, N-ethylcarbazole, N-phenylcarbazole, indole, and quinoline.

Preferred examples of the compound represented by the general formula (5-1) or (5-2) are given below. However, the present invention is not limited to these compounds.
The compounds represented by the general formulas (5-1) and (5-2) include compounds described in Japanese Patent Publication No. 58-5739, Japanese Patent No. 2529299, and the like. The compound represented by (5) can be produced by a so-called modified Wittig reaction or Wittig reaction by reaction of a corresponding phosphonic acid ester compound or triphenylphosphonium salt compound with a corresponding aldehyde compound, The compound represented by the general formula (5-2) can be produced by reducing the compound represented by the general formula (5-1).

The compound used for the charge transport layer is represented by the following general formula (6).

(Wherein R ₁₀₁ and R ₁₀₂ represent a substituted or unsubstituted alkyl group or a substituted or unsubstituted aromatic ring group, and may be the same or different. However, any one of R ₁₀₁ and R ₁₀₂ may be used. Is a substituted or unsubstituted aromatic ring group, and R ₁₀₁ and R ₁₀₂ may be bonded to each other to form a substituted or unsubstituted heterocyclic group containing a nitrogen atom, and Ar ₅₇ is a substituted or unsubstituted group. Represents an aromatic ring group of
The diamine compound represented by the general formula (6) is described as a dye intermediate or a polymer compound precursor in JP-B-62-13382, US Pat. Nos. 4,223,144, 3,271,383 and 3,291,788. .
The diamine compound represented by the general formula (6) can be easily produced by the method described in the literature (E. Elceand AS Hay, Polymer, Vol. 37 No. 9, 1745 (1996)). That is, by reacting a dihalide represented by the following general formula (8) and a secondary amine compound represented by the following general formula (9) at a temperature from room temperature to about 100 ° C. in the presence of a basic compound. Obtainable.

_{BH 2 C-Ar 1 CH 2} B (8)
(In the formula, Ar ₁ represents a substituted or unsubstituted aromatic ring group. B represents a halogen atom.)
(Wherein R ₁₀₁ and R ₁₀₂ represent a substituted or unsubstituted alkyl group or a substituted or unsubstituted aromatic ring group, and may be the same or different. However, any one of R ₁₀₁ and R ₁₀₂ may be used. Is a substituted or unsubstituted aromatic ring group, and R ₁₀₁ and R ₁₀₂ may be bonded to each other to form a substituted or unsubstituted heterocyclic group containing a nitrogen atom.)
Specific examples of the basic compound include potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, sodium hydride, sodium methylate, potassium t-butoxide and the like. Examples of the reaction solvent include dioxane, tetrahydrofuran, toluene, xylene, dimethyl sulfoxide, N, N-dimethylformamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, acetonitrile and the like.

Specific examples of the alkyl group represented by R ₁₀₁ and R ₁₀₂ in the description of the general formulas (6) and (9) include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, and an undecanyl group. And so on. The aromatic ring groups represented by R ₁₀₁ , R ₁₀₂ and Ar ₅₇ in the description of the general formulas (6) and (9) include aromatics such as benzene, biphenyl, naphthalene, anthracene, fluorene and pyrene. Examples thereof include a ring and an aromatic heterocyclic group such as pyridine, quinoline, thiophene, furan, oxazole, oxadiazole, and carbazole. These substituents include those exemplified in the above specific examples of alkyl groups, alkoxy groups such as methoxy group, ethoxy group, propoxy group and butoxy group, or halogen atoms of fluorine atom, chlorine atom, bromine atom and iodine atom. Atoms, the aromatic hydrocarbon groups, and heterocyclic groups such as pyrrolidine, piperidine, piperazine and the like can be mentioned. Further, when R ₁₀₁ and R ₁₀₂ are bonded to each other to form a heterocyclic group containing a nitrogen atom, the heterocyclic group includes a condensed heterocycle in which an aromatic hydrocarbon group is condensed with a pyrrolidino group, a piperidino group, a piperazino group, or the like. A cyclic group can be mentioned.
Below, the preferable example of a compound represented by the said General formula (6) is given. However, the present invention is not limited to these compounds.

Note) Compound No. 35 to 37, the groups shown in the R ₁₀₁ and R ₁₀₂ columns are
Is a -NR ₁₀₁ R ₁₀₂ groups.

<About other additives>
In the present invention, in order to improve environmental resistance, in particular, for the purpose of improving the stability of image quality, each layer such as a cross-linked charge transport layer, a charge generation layer, a charge transport layer, an undercoat layer, an intermediate layer, etc. An antioxidant can be added to the. In the present invention, it was effective to add it to the charge transport layer.
The following are mentioned as antioxidant which can be used for this invention.
<Phenolic compound>
2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3,5-di-t-butyl-4 -Hydroxyphenyl) propionate, 2,2'-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2'-methylene-bis- (4-ethyl-6-tert-butylphenol), 4, 4'-thiobis- (3-methyl-6-tert-butylphenol), 4,4'-butylidenebis- (3-methyl-6-tert-butylphenol), 1,1,3-tris- (2-methyl-4 -Hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [meth -3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3'-bis (4'-hydroxy-3'-t-butylphenyl) buty Rick acid] cricol ester, tocopherols and the like.

<Paraphenylenediamines>
N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N'- Di-isopropyl-p-phenylenediamine, N, N'-dimethyl-N, N'-di-t-butyl-p-phenylenediamine and the like.
<Hydroquinones>
2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2-octadecenyl) ) -5-methylhydroquinone and the like.
<Organic sulfur compounds>
Dilauryl-3, 3'-thiodipropionate, distearyl-3, 3'-thiodipropionate, ditetradecyl-3, 3'-thiodipropionate and the like.
<Organic phosphorus compounds>
Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine, and the like.
These compounds are known as antioxidants such as rubbers, plastics and fats and oils, and commercially available products can be easily obtained.
The addition amount of the antioxidant in the present invention is preferably 0.01 to 10 parts by weight with respect to the total weight of the layer to be added.
When an additive having only an antioxidant ability is used, its characteristic expression depends on the amount of antioxidant added, so that a considerable amount of addition may be required to obtain a sufficient effect. When the amount added is excessively increased, the bright portion potential is increased. However, an electrophotographic photoreceptor satisfying the relational expressions (1) and (2) of the ionization potential of the charge transport layer, the ionization potential of the charge generation layer, and the ionization potential of the cross-linked charge transport layer according to claim 1 is sufficient. Even when an antioxidant sufficient to obtain the effect is added, the increase in the bright portion potential is small as compared with the conventional electrophotographic photosensitive member having the same configuration.

<< Crosslinked charge transport layer >>
Next, the constituent material of the crosslinkable charge transport layer of the present invention will be described.
Since it is necessary to transport charges while maintaining wear resistance, the crosslinked charge transport layer is used by curing a radical polymerizable monomer having no charge transport function and a radical polymerizable compound having a charge transport function. . Curing is generally an intermolecular reaction of a low-molecular compound having a plurality of functional groups or a high-molecular compound is bonded (for example, covalent bond) between molecules by applying energy such as heat, light, electron beam, etc. This reaction forms an original network structure.
Examples of the curable resin include a thermosetting resin that is polymerized by heat, a photocurable resin that is polymerized by light such as ultraviolet rays and visible light, an electron beam curable resin that is polymerized by electronic properties, and a curing agent as necessary. Or a catalyst, a polymerization initiator, or the like.
In order to cure the curable resin, it is necessary that a reactive compound (for example, a monomer or an oligomer) has a functional group that causes a polymerization reaction. Examples of these functional groups include acryloyl groups and / or methacryloyl groups. Further, in the curing reaction, the larger the number of functional groups in one molecule of the reactive monomer, the stronger the three-dimensional network structure becomes, and the trifunctional or higher functionality is particularly effective. As a result, the curing density is increased, the hardness is high, the elasticity is high, the uniformity is smooth, and the smoothness is improved. This is effective for improving the durability and image quality of the photoreceptor.

  In the present invention, as described above, a three-dimensionally developed network structure is obtained by curing reaction of a reactive monomer having no charge transporting structure and a reactive compound having a charge transporting structure on a conductive support. Form. In this case, it is possible to further increase the degree of curing by previously mixing a curing agent, a catalyst, a polymerization initiator and the like, which is particularly effective in the present invention. As a result, the wear resistance of the cross-linked charge transport layer is further improved, and unreacted functional groups are less likely to remain, which is effective in improving the wear resistance and suppressing the deterioration of electrostatic characteristics. In addition, since the reaction is uniform, cracks and distortions are less likely to occur, and the cleaning property can be improved. For example, it is possible to obtain high effects for improving the durability and image quality of the photoreceptor.

  The radical polymerizable monomer having no charge transporting property is, for example, a hole transporting structure such as triarylamine, hydrazone, pyrazoline, carbazole, etc. A monomer having no electron transport structure such as an aromatic ring and having a radical polymerizable functional group. The radical polymerizable functional group may be any group as long as it has a carbon-carbon double bond and is capable of radical polymerization. Examples of these radical polymerizable functional groups include 1-substituted ethylene functional groups and 1,1-substituted ethylene functional groups shown below.

(1) 1-substituted ethylene functional group Examples of the 1-substituted ethylene functional group include functional groups represented by the following formulas.
CH ₂ = _{CH-X 1} -
.... Formula (10)
(In the formula, X ₁ is an arylene group such as a phenylene group or a naphthylene group which may have a substituent, an alkenylene group which may have a substituent, a —CO— group, a —COO— group. , -CONR ₇₈ group (R ₇₈ represents an alkyl group such as hydrogen, methyl group or ethyl group, an aralkyl group such as benzyl group, naphthylmethyl group or phenethyl group, or an aryl group such as phenyl group or naphthyl group). Or represents -S- group.)
Specific examples of these substituents include vinyl group, styryl group, 2-methyl-1,3-butadienyl group, vinylcarbonyl group, acryloyloxy group, acryloylamide group, vinylthioether group and the like.

(2) 1,1-substituted ethylene functional group Examples of the 1,1-substituted ethylene functional group include functional groups represented by the following formulas.
CH ₂ = _{CY-X 2} -
.... Formula (11)
(In the formula, Y is an aryl group such as an alkyl group which may have a substituent, an aralkyl group which may have a substituent, a phenyl group which may have a substituent, or a naphthyl group. Group, halogen atom, cyano group, nitro group, alkoxy group such as methoxy group or ethoxy group, -COOR ₇₉ group (R ₇₉ is an alkyl such as hydrogen atom, optionally substituted methyl group, ethyl group) Group, an aralkyl group such as benzyl and phenethyl group which may have a substituent, an aryl group such as phenyl group and naphthyl group which may have a substituent, or -CONR ₈₀ R ₈₁ (R ₈₀ and R ₈₁ is a hydrogen atom, which may have a substituent an alkyl group such as methyl group and ethyl group, which may have a substituent group benzyl group, Aral such naphthylmethyl group or a phenethyl group, Le group or substituent a phenyl group which may have a represents an aryl group such as phenyl or naphthyl, which may be the same or different from each other.) Further, X ₂ is the same as X ₁ in the formula 10 substituents and a single bond, an alkylene group. However, Y, at least one is an oxycarbonyl group of X _2, a cyano group, an alkenylene group, and an aromatic ring.)
Specific examples of these substituents include an α-acryloyloxy chloride group, a methacryloyloxy group, an α-cyanoethylene group, an α-cyanoacryloyloxy group, an α-cyanophenylene group, and a methacryloylamino group.

  In addition, examples of the substituent further substituted with the substituent for X and Y include, for example, a halogen atom, a nitro group, an alkyl group such as a cyano group, a methyl group, and an ethyl group, an alkoxy group such as a methoxy group and an ethoxy group, Examples thereof include aryloxy groups such as phenoxy group, aryl groups such as phenyl group and naphthyl group, aralkyl groups such as benzyl group and phenethyl group. Among these radical polymerizable functional groups, acryloyloxy group and methacryloyloxy group are particularly useful. The number of functional groups of the radically polymerizable monomer or oligomer having no charge transporting structure is preferably polyfunctional and more preferably trifunctional or higher. When trifunctional or higher-functional radically polymerizable monomers are cured, a three-dimensional network structure is developed, and a high hardness and high elasticity layer having a very high crosslink density is obtained. And scratch resistance are achieved. However, depending on the curing conditions and the materials used, a large number of bonds are instantaneously formed in the curing reaction, so that internal stress due to volume shrinkage occurs, and cracks and film peeling may easily occur. In that case, it may be improved by using a monofunctional or bifunctional radically polymerizable monomer or by mixing them.

Hereinafter, a radical polymerizable monomer having no trifunctional or higher functional charge transport structure effective for improving the wear resistance will be described.
A compound having three or more acryloyloxy groups can be prepared by, for example, using a compound having three or more hydroxyl groups in the molecule and acrylic acid (salt), acrylic acid halide, or acrylic ester, and performing an ester reaction or a transesterification reaction. Obtainable. A compound having three or more methacryloyloxy groups can be obtained in the same manner. Further, the radical polymerizable functional groups in the monomer having three or more radical polymerizable functional groups may be the same or different.
Specific examples of the radical polymerizable monomer having no charge transport structure include the following, but are not limited to these compounds.
That is, as the radical polymerizable monomer used in the present invention, trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, HPA-modified trimethylolpropane triacrylate, EO-modified trimethylolpropane triacrylate, PO-modified trimethylol. Propane triacrylate, caprolactone modified trimethylolpropane triacrylate, ECH modified trimethylolpropane triacrylate, HPA modified trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol triacrylate, ECH modified glycerol triacrylate , EO-modified glycerol triacrean , PO-modified glycerol triacrylate, tris (acryloxyethyl) isocyanurate, alkyl-modified dipentaerythritol tetraacrylate, alkyl-modified dipentaerythritol triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, EO-modified phosphorus Acid triacrylate, 2, 2, 5, 5, -tetrahydroxymethylcyclopentanone tetraacrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, 2-ethylhexyl carbitol acrylate , 3-methoxybutyl acrylate, benzyl acrylate, cyclohexyl acrylate , Isoamyl acrylate, isobutyl acrylate, methoxytriethylene glycol acrylate, phenoxytetraethylene glycol acrylate, cetyl acrylate, isostearyl acrylate, stearyl acrylate, styrene monomer, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, EO-modified bisphenol A diacrylate, EO-modified bisphenol F diacrylate And neopentyl glycol diacrylate. Among them, trimethylol propylene Triacrylate (TMPTA), HPA-modified trimethylolpropane triacrylate, EO-modified trimethylolpropane triacrylate, PO-modified trimethylolpropane triacrylate, and ECH-modified trimethylolpropane triacrylate, but the present invention is not limited thereto. It is not done. In addition, ethyleneoxy modification is described as EO modification, propyleneoxy modification as PO modification, epichlorohydrin modification as ECH modification, and alkylene modification as HPA modification.
Examples of the radical polymerizable oligomer include epoxy acrylate, urethane acrylate, and polyester acrylate oligomers.
These may be used alone or in combination of two or more.

The trifunctional or higher functional radical polymerizable monomer having no charge transport structure used in the present invention has a molecular weight relative to the number of functional groups in the monomer in order to form a dense crosslink in the crosslinkable charge transport layer. The ratio (molecular weight / functional group number) is preferably 250 or less. Further, when this ratio is larger than 250, the cross-linked charge transport layer is soft and wear resistance is somewhat lowered. Therefore, among monomers exemplified above, monomers having a modifying group such as EO, PO, caprolactone, etc. It is not preferable to use a compound having a long modifying group alone.

Further, the proportion of the trifunctional or higher functional radical polymerizable monomer having no charge transport structure used in the crosslinkable charge transport layer is 20 to 80% by weight, preferably 30 to 70% by weight based on the total amount of the crosslinkable charge transport layer. %. When the monomer component is less than 20% by weight, the three-dimensional crosslink density of the crosslinkable charge transport layer is small, and a drastic improvement in wear resistance is not achieved as compared with the case of using a conventional thermoplastic binder resin. On the other hand, if it is 80% by weight or more, the content of the charge transporting compound is lowered, and the electrical characteristics are deteriorated. The electrical characteristics and abrasion resistance required differ depending on the process used, and the film thickness of the cross-linked charge transport layer of the photoreceptor varies accordingly. A range of 70% by weight is most preferred.

<Description of radical polymerizable monomer having charge transporting structure>
Examples of the radically polymerizable compound having a charge transporting structure used in the present invention include hole transporting structures such as triarylamine, hydrazone, pyrazoline and carbazole, such as condensed polycyclic quinone, diphenoquinone, cyano group and nitro group. It refers to a compound having an electron transport structure such as an electron-withdrawing aromatic ring and having a radical polymerizable functional group. The radical polymerizable functional group may be any group as long as it has a carbon-carbon double bond and is capable of radical polymerization.

Any number of functional groups can be used as the radically polymerizable compound having a charge transporting structure used in the cross-linked charge transport layer of the present invention. From the point of view, it is more preferable. In the case of bifunctional, the crosslink structure is fixed by a plurality of bonds and the crosslink density is further increased. However, since the charge transporting structure is very bulky, the distortion of the cured layer structure is increased, and the internal stress of the layer may be increased. is there. In addition, the intermediate structure (cation radical) at the time of charge transport cannot be stably maintained, and there is a possibility that a decrease in sensitivity due to charge trapping and an increase in residual potential are likely to occur. The tendency is particularly remarkable for those having three or more functional groups.
As the charge transporting structure of the radical polymerizable compound having a charge transporting structure, any material can be used as long as it can provide a charge transporting function. Among them, the triarylamine structure is highly effective and useful. is there. This is considered to be because there are many hopping sites and π conjugation spreads. Triarylamines are easily conjugated to each other in the radical cation state. For these reasons, the triarylamine structure is excellent in the charge transport function. In particular, when the compound represented by the formula (1) or (2) is used, electrical characteristics such as sensitivity and residual potential are favorably maintained.

[Wherein, R ₄₀ represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a cyano group, a nitro group, A group, an alkoxy group, —COOR ₄₁ (R ₄₁ represents a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or an aryl group which may have a substituent. ), A carbonyl halide group or CONR ₄₂ R ₄₃ (R ₄₂ and R ₄₃ have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Represents an aryl group which may be the same or different from each other. Ar ₂ and Ar ₃ represent a substituted or unsubstituted arylene group, and may be the same or different. . Ar ₄ and Ar ₅ represent a substituted or unsubstituted aryl group, and may be the same or different. X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group. Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group, or an alkyleneoxycarbonyl group. m and n represent an integer of 0 to 3. ]

Specific examples of the substituents in the general formulas (1) and (2) are shown below.
In the general formulas (1) and (2), in the substituent of R ₄₀ , examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group, and examples of the aryl group include a phenyl group and a naphthyl group. The aralkyl group includes a benzyl group, a phenethyl group, and a naphthylmethyl group, and the alkoxy group includes a methoxy group, an ethoxy group, a propoxy group, and the like. These include a halogen atom, a nitro group, a cyano group, and a methyl group. Substituted with an alkyl group such as an ethyl group, an alkoxy group such as a methoxy group or an ethoxy group, an aryloxy group such as a phenoxy group, an aryl group such as a phenyl group or a naphthyl group, an aralkyl group such as a benzyl group or a phenethyl group, etc. May be.
Of the substituents for R ₄₀ , particularly preferred are a hydrogen atom and a methyl group. Substituted or unsubstituted Ar ₄ and Ar ₅ are aryl groups, and examples of the aryl group include condensed polycyclic hydrocarbon groups, non-condensed cyclic hydrocarbon groups, and heterocyclic groups.

  The condensed polycyclic hydrocarbon group preferably has 18 or less carbon atoms forming a ring, for example, a pentanyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptaenyl group, a biphenylenyl group, an as-indacenyl group. , S-indacenyl group, fluorenyl group, acenaphthylenyl group, preadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrenyl group, aceanthrylenyl group, triphenylyl group, pyrenyl group , A chrycenyl group, a naphthacenyl group and the like. Examples of the non-fused cyclic hydrocarbon group include monovalent groups of monocyclic hydrocarbon compounds such as benzene, diphenyl ether, polyethylene diphenyl ether, diphenyl thioether and diphenyl sulfone, or biphenyl, polyphenyl, diphenylalkane, diphenylalkene, diphenylalkyne, Monovalent groups of non-condensed polycyclic hydrocarbon compounds such as triphenylmethane, distyrylbenzene, 1,1-diphenylcycloalkane, polyphenylalkane, and polyphenylalkene, or ring assemblies such as 9,9-diphenylfluorene And monovalent groups of hydrocarbon compounds. Examples of the heterocyclic group include monovalent groups such as carbazole, dibenzofuran, dibenzothiophene, oxadiazole, and thiadiazole.

The aryl group represented by Ar ₄ or Ar ₅ may have a substituent as shown below, for example.
(1) Halogen atom, cyano group, nitro group and the like.
(2) an alkyl group;
Preferably, it is a C1-C12, particularly C1-C8, more preferably a C1-C4 linear or branched alkyl group, and these alkyl groups further include a fluorine atom, a hydroxyl group, a cyano group, and a C1-C4 alkoxy group. , A phenyl group or a halogen atom, a C1-C4 alkyl group or a C1-C4 alkoxy group substituted with a phenyl group.
Specifically, methyl group, ethyl group, n-butyl group, i-propyl group, t-butyl group, s-butyl group, n-propyl group, trifluoromethyl group, 2-hydroxyethyl group, 2-ethoxyethyl Group, 2-cyanoethyl group, 2-methoxyethyl group, benzyl group, 4-chlorobenzyl group, 4-methylbenzyl group, 4-phenylbenzyl group and the like.

(3) an alkoxy group _(-OR 82);
(In the formula, R ₈₂ represents an alkyl group defined in (2).)
Specifically, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, t-butoxy group, n-butoxy group, s-butoxy group, i-butoxy group, 2-hydroxyethoxy group, benzyloxy group And a trifluoromethoxy group.
(4) aryloxy group;
Examples of the aryl group include a phenyl group and a naphthyl group. This may contain a C1-C4 alkoxy group, a C1-C4 alkyl group or a halogen atom as a substituent. Specific examples include a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a 4-methoxyphenoxy group, and a 4-methylphenoxy group.
(5) an alkyl mercapto group or an aryl mercapto group;
Specific examples include a methylthio group, an ethylthio group, a phenylthio group, and a p-methylphenylthio group.
(6) a substituent represented by the following formula;
(Wherein R _d and R _e each independently represents a hydrogen atom, an alkyl group defined in (2) above, or an aryl group. Examples of the aryl group include a phenyl group, a biphenyl group, and a naphthyl group, These may contain a C1-C4 alkoxy group, a C1-C4 alkyl group or a halogen atom as a substituent. R _d and R _e may form a ring together.)
Specifically, amino group, diethylamino group, N-methyl-N-phenylamino group, N, N-diphenylamino group, N, N-di (tolyl) amino group, dibenzylamino group, piperidino group, morpholino group And pyrrolidino group.
(7) An alkylenedioxy group or an alkylenedithio group such as a methylenedioxy group or a methylenedithio group.
(8) A substituted or unsubstituted styryl group, a substituted or unsubstituted β-phenylstyryl group, a diphenylaminophenyl group, a ditolylaminophenyl group, and the like.
Examples of the arylene group represented by Ar ₂ and Ar ₃ include a divalent group derived from the aryl group represented by Ar ₄ and Ar ₅ .

X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group.
The substituted or unsubstituted alkylene group is a C1-C12, preferably C1-C8, more preferably a C1-C4 linear or branched alkylene group, and these alkylene groups further include a fluorine atom, a hydroxyl group, It may have a cyano group, a C1-C4 alkoxy group, a phenyl group or a halogen atom, a C1-C4 alkyl group, or a phenyl group substituted with a C1-C4 alkoxy group. Specifically, methylene group, ethylene group, n-butylene group, i-propylene group, t-butylene group, s-butylene group, n-propylene group, trifluoromethylene group, 2-hydroxyethylene group, 2-ethoxyethylene Group, 2-cyanoethylene group, 2-methoxyethylene group, benzylidene group, phenylethylene group, 4-chlorophenylethylene group, 4-methylphenylethylene group, 4-biphenylethylene group and the like.

The substituted or unsubstituted cycloalkylene group is a C5-C7 cyclic alkylene group, and these cyclic alkylene groups have a fluorine atom, a hydroxyl group, a C1-C4 alkyl group, and a C1-C4 alkoxy group. May be. Specific examples include a cyclohexylidene group, a cyclohexylene group, and a 3,3-dimethylcyclohexylidene group.
Examples of the substituted or unsubstituted alkylene ether group include alkyleneoxy groups such as ethyleneoxy group and propyleneoxy group, alkylenedioxy groups derived from ethylene glycol, propylene glycol, and the like, diethylene glycol, tetraethylene glycol, tripropylene glycol, and the like. Examples thereof include a derived di- or poly (oxyalkylene) oxy group, and the alkylene group of the alkylene ether group may have a substituent such as a hydroxyl group, a methyl group, or an ethyl group.

Examples of the vinylene group include substituents represented by the following general formula.
[Wherein, R _f is hydrogen, an alkyl group (same as the alkyl group defined in (2) above), an aryl group (same as the aryl group represented by Ar ₄ or Ar ₅ above), a is 1 or 2, b represents 1-3. ]
Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group, or an alkyleneoxycarbonyl group.
Examples of the substituted or unsubstituted alkylene group include the same alkylene groups as those described above for X.
Examples of the substituted or unsubstituted alkylene ether group include the alkylene ether group represented by X.
Examples of the alkyleneoxycarbonyl group include a caprolactone-modified group.

Further, the radical polymerizable compound having a monofunctional charge transport structure of the present invention is more preferably a compound having a structure represented by the following general formula (10).

(In the formula, o, p and q are each an integer of 0 or 1, R _a represents a hydrogen atom or a methyl group, and R _b and R _c represent a substituent other than a hydrogen atom and an alkyl group having 1 to 6 carbon atoms. And a plurality of s and t each represent an integer of 0 to 3. Za is a single bond, a methylene group, an ethylene group,
Represents. )
As the compound represented by the general formula (10), compounds having a methyl group or an ethyl group are particularly preferable as substituents for R _b and R _c .

  The radically polymerizable compound having a monofunctional charge transport structure represented by the general formulas (1) and (2), particularly (10) used in the present invention is polymerized by opening a carbon-carbon double bond on both sides. Therefore, it does not become a terminal structure, but is incorporated in a chain polymer and cross-linked by polymerization with a radical polymerizable monomer that does not have a charge transporting structure. And present in a cross-linked chain between the main chain and the main chain (this cross-linked chain includes an intermolecular cross-linked chain between one polymer and another polymer, and a main chain in a folded state in one polymer. There is an intramolecular cross-linked chain in which a site with a chain and another site derived from a polymerized monomer at a position away from this in the main chain are cross-linked). Triarylamines that hang from the chain portion even when present in the bridging chain The structure has at least three aryl groups arranged in a radial direction from the nitrogen atom and is bulky, but is not directly bonded to the chain part but suspended from the chain part via a carbonyl group or the like. Since these triarylamine structures can be spatially adjacent to each other in the polymer, there is little structural distortion in the molecule. In the case of a cross-linked charge transport layer of an electrophotographic photoreceptor, it is presumed that an intramolecular structure relatively free from interruption of the charge transport path can be taken.

Specific examples of the radically polymerizable compound having a monofunctional charge transporting structure of the present invention are shown below, but are not limited to the compounds having these structures.

  In the radical polymerizable compound having a charge transport structure used in the present invention, this component is 20 to 80% by weight, preferably 30 to 70% by weight, based on the total amount of the cross-linked charge transport layer. If this component is less than 20% by weight, the charge transport performance of the crosslinkable charge transport layer cannot be maintained sufficiently, and deterioration of electrical characteristics such as a decrease in sensitivity and an increase in residual potential will occur with repeated use. On the other hand, if it exceeds 80% by weight, the content of the radically polymerizable monomer having no charge transport structure is lowered, and the crosslinking density is lowered, so that high wear resistance is not exhibited. Although the electrical characteristics and abrasion resistance required differ depending on the process used, it cannot be said unconditionally, but considering the balance of both characteristics, the range of 30 to 70% by weight is most preferable.

As described above, a cured product of a tri- or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure is particularly effective. Bifunctional radically polymerizable monomers and radically polymerizable oligomers can also be used, and may be very effective depending on the material. Known radical polymerizable monomers and oligomers can be used.
Examples of the monofunctional radical monomer include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, 2-ethylhexyl carbitol acrylate, 3-methoxybutyl acrylate, benzyl acrylate, and cyclohexyl acrylate. , Isoamyl acrylate, isobutyl acrylate, methoxytriethylene glycol acrylate, phenoxytetraethylene glycol acrylate, cetyl acrylate, isostearyl acrylate, stearyl acrylate, styrene monomer, and the like.
Examples of the bifunctional radical polymerizable monomer include 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1, Examples include 6-hexanediol dimethacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, bisphenol A-EO modified diacrylate, bisphenol F-EO modified diacrylate, and neopentyl glycol diacrylate.

Examples of the functional monomer include those substituted with a fluorine atom such as octafluoropentyl acrylate, 2-perfluorooctylethyl acrylate, 2-perfluorooctylethyl methacrylate, 2-perfluoroisononylethyl acrylate, No. 60503, JP-B-6-45770, siloxane repeating units: 20-70 acryloyl polydimethylsiloxane ethyl, methacryloyl polydimethylsiloxane ethyl, acryloyl polydimethylsiloxane propyl, acryloyl polydimethylsiloxane butyl, diacryloyl polydimethylsiloxane Examples include vinyl monomers having a polysiloxane group such as diethyl, acrylates and methacrylates.
Examples of the radical polymerizable oligomer include epoxy acrylate, urethane acrylate, and polyester acrylate oligomers.

<Description of initiator>
The crosslinkable charge transport layer of the present invention comprises a radical polymerizable monomer (preferably trifunctional or higher) having no charge transport structure and a radical polymerizable compound (preferably monofunctional) having a charge transport structure. , A cross-linked charge transport layer that is simultaneously cured using at least one of light and ionizing radiation. When forming a cross-linkable charge transport layer using thermal energy or light energy, In order to advance this crosslinking reaction efficiently, a polymerization initiator may be used in the crosslinked charge transport layer. When performing crosslinking using ionizing radiation, it is usually possible to obtain a crosslinking reaction without using a polymerization initiator, but in order to cure the uncured components remaining after irradiation with ionizing radiation, as a post-treatment Heat energy and / or light energy can be applied, but even in that case, it is effective to add a polymerization initiator shown below.
As the thermal polymerization initiator, 2,5-dimethylhexane-2,5-dihydroperoxide, dicumyl peroxide, benzoyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di ( Peroxybenzoyl) hexyne-3, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, peroxide initiators such as lauroyl peroxide, azobisisobutylnitrile, azobiscyclohexanecarbonitrile Azo initiators such as methyl azobisisobutyrate, azobisisobutylamidine hydrochloride, 4,4′-azobis-4-cyanovaleric acid.

As photopolymerization initiators, 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, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2- Acetophenone-based or ketal-based photopolymerization initiators such as methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, Benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether Benzoin ether photopolymerization initiators such as benzoin isopropyl ether, benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoylphenyl ether, acrylated benzophenone, Benzophenone-based photopolymerization initiators such as 1,4-benzoylbenzene, thioxanthones such as 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, and 2,4-dichlorothioxanthone Photopolymerization initiator, bis (cyclopentadienyl) -di-chloro-titanium, bis (cyclopentadienyl) -di-phenyl-titanium, bis (cyclopentadienyl) -bis ( 3,4,5,6 pentafluorophenyl) titanium, bis (cyclopentadienyl) -bis (2,6-difluoro-3- (pyrrol-1-yl) phenyl) titanium, and other titanocene photopolymerization initiators As other photopolymerization initiators, ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenyl Phosphine oxide, bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10-phenanthrene, acridine compound, triazine compound, imidazole compound Be .
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, (2-dimethylamino) ethyl benzoate, 4,4′-dimethylaminobenzophenone, and the like.
These polymerization initiators may be used alone or in combination of two or more. The content of the polymerization initiator is 0.5 to 40 parts by weight, preferably 1 to 20 parts by weight with respect to 100 parts by weight of the total content having radical polymerizability.

<Description of filler addition>
The crosslinkable charge transport layer of the present invention is a crosslinkable charge transport layer obtained by simultaneously curing a radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a charge transport structure. Filler fine particles can be contained for the purpose of improving the wearability.
The crosslinked fine particle-containing charge transport layer of the present invention has a high crosslinking density, and has higher abrasion resistance of the resin part than the non-crosslinked filler-containing binder resin layer, and the above uneven wear is suppressed. In addition to this, the filler fine particles dispersed in the resin are caught by the cured resin cross-linked matrix, and since the filler holding power of the cross-linked matrix is large, the filler is prevented from falling off. Therefore, it is considered that the wear resistance is greatly enhanced.
As the filler fine particles, the following can be used. Examples of the organic filler material include fluororesin powder such as polytetrafluoroethylene, silicone resin powder, and carbon fine particles. The carbon fine particles are particles having a structure mainly composed of carbon, and are particles having a structure such as amorphous, diamond, graphite, amorphous carbon, fullerene, zeppelin, carbon nanotube, carbon nanohorn. Among these structures, particles containing hydrogen-containing diamond-like carbon or amorphous carbon structure have good mechanical and chemical durability. The diamond-like carbon or amorphous carbon film containing hydrogen is SP3.
It is a particle in which similar structures such as a diamond structure having an orbit, a graphite structure having an SP2 orbit, and an amorphous carbon structure are mixed. Diamond-like carbon or amorphous carbon fine particles are not limited to carbon, but may contain other elements such as hydrogen, oxygen, nitrogen, fluorine, boron, phosphorus, chlorine, bromine and iodine. Absent.
Examples of inorganic filler materials include metal powders such as copper, tin, aluminum, and indium, metal oxides such as silicon oxide, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, and bismuth oxide, and potassium titanate. An inorganic material is mentioned. In particular, it is advantageous to use an inorganic material among them from the viewpoint of the hardness of the filler. In particular, metal oxides are good, and silicon oxide, aluminum oxide, and titanium oxide can be used effectively. Also, fine particles such as colloidal silica and colloidal alumina can be used effectively.

The average primary particle size of the filler is preferably 0.01 to 0.9 μm from the viewpoint of light transmittance and wear resistance of the cross-linked charge transport layer, and more preferably 0.1 μm to 0.5 μm. When the average primary particle size of the filler is 0.01 μm or less, it causes a decrease in wear resistance, a decrease in dispersibility, etc., and when it is 0.9 μm or more, the sedimentation property of the filler is promoted in the dispersion liquid. In addition, toner filming may occur.
The higher the filler material concentration in the cross-linked charge transport layer, the better the wear resistance, but if it is too high, the residual potential will increase, the writing light transmittance of the surface layer will decrease, causing side effects There is. Therefore, it is about 50% by weight or less, preferably about 30% by weight or less based on the total solid content. Furthermore, these fillers can be surface-treated with at least one kind of surface treatment agent, and it is preferable from the viewpoint of filler dispersibility. Lowering the dispersibility of the filler not only increases the residual potential, but also lowers the transparency of the coating, causes defects in the coating, and lowers the wear resistance. It can develop into a big problem.

As the surface treatment agent, a conventionally used surface treatment agent can be used, but a surface treatment agent capable of maintaining the insulating properties of the filler is preferable. For example, a titanate coupling agent, an aluminum coupling agent, a zircoaluminate coupling agent, a higher fatty acid, etc., or a mixing treatment of these with a silane coupling agent, Al ₂ O ₃ , TiO ₂ , ZrO ₂ , Silicone, aluminum stearate, or the like, or a mixture thereof is more preferable from the viewpoint of filler dispersibility and image drift prevention. The treatment with the silane coupling agent has a strong influence on the image flow, but the influence may be suppressed by performing a mixing treatment of the surface treatment agent and the silane coupling agent. The surface treatment amount varies depending on the average primary particle size of the filler used, but is preferably 3 to 30% by weight, and more preferably 5 to 20% by weight. If the surface treatment amount is less than this, the filler dispersion effect cannot be obtained, and if it is too much, the residual potential is significantly increased. These filler materials may be used alone or in combination of two or more.

<Description of other additives>
Furthermore, the coating liquid of the present invention can contain additives such as various plasticizers (for the purpose of stress relaxation and adhesion improvement), leveling agents, and low molecular charge transport materials having no radical reactivity as required. As these additives, known additives can be used, and as plasticizers, those used in general resins such as dibutyl phthalate and dioctyl phthalate can be used, and the amount used is the total solid content of the coating liquid. It is suppressed to 20 parts by weight or less, preferably 10 parts by weight or less with respect to 1 part by weight. As leveling agents, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain can be used, and the amount used is based on the total solid content of the coating liquid. 3 parts by weight or less is appropriate.

<About film production method>
The crosslinked charge transport layer of the present invention contains at least a radical polymerizable monomer (preferably trifunctional or higher) having no charge transport structure and a radical polymerizable compound (preferably monofunctional) having a charge transport structure. It is formed by applying and curing a coating solution on the photosensitive layer described later. When the radically polymerizable monomer is a liquid, the coating liquid used for coating can be coated by dissolving other components in the liquid. However, if necessary, the coating liquid is diluted with a solvent and coated. The solvent used here is not particularly limited as long as it is usually used. For example, alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, ethers such as tetrahydrofuran, dioxane and propyl ether, dichloromethane And halogen series such as dichloroethane, trichloroethane and chlorobenzene, aromatic series such as benzene, toluene and xylene, and cellosolv series such as methyl cellosolve, ethyl cellosolve and cellosolve acetate. These solvents may be used alone or in combination of two or more.
The coating method used for forming the crosslinkable charge transport layer is not particularly limited as long as it is a commonly used coating method. A coating method may be appropriately selected depending on the viscosity of the coating liquid, the desired thickness of the crosslinkable charge transport layer, and the like. Examples include dip coating, spray coating, bead coating, ring coating, and the like.

In this invention, after apply | coating this coating liquid, a bridge | crosslinking type charge transport layer is hardened by giving energy from the outside. As the external energy used at this time, heat energy, light energy, or energy using ionizing radiation can be used. However, when ionizing radiation is used, the energy penetration depth and energy intensity are Therefore, since there is a concern about deterioration of electrophotographic characteristics accompanying deterioration of the constituent material of the electrophotographic photosensitive member, it is preferable to cure using thermal energy and light energy. In addition, since curing using light energy can be expected to reduce the amount of solvent used during production, reduce energy required for crosslinking, and further increase the strength of the crosslinked film, it is more preferable to use light energy and effectively Any two of the above means may be used in combination for crosslinking.
As thermal energy, gas such as air and nitrogen, steam, various heat media, infrared rays, and electromagnetic waves can be used, and heating is performed from the coated surface side or the support side. The heating temperature is preferably 100 ° C. or higher and 170 ° C. or lower. When the temperature is lower than 100 ° C., the reaction rate is slow, so that productivity is lowered and unreacted material remains in the film. On the other hand, when the treatment is performed at a temperature higher than 170 ° C., the shrinkage of the film due to the cross-linking is increased, and the skin-like defects and cracks may be generated on the surface, or peeling may occur at the interface with the adjacent layer. Further, when the volatile component in the photosensitive layer is sprayed to the outside, it is not preferable because desired electrical characteristics may not be obtained. When using a resin having a large shrinkage due to crosslinking, it is also effective to complete the crosslinking at a high temperature of 100 ° C. or higher after preliminary crosslinking at a low temperature of less than 100 ° C.

As the light energy, a light source such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc metal halide lamp or the like may be used. The radical polymerizable compound (preferably monofunctional) having a charge transporting structure, and further, the absorption characteristics of the photopolymerization initiator used in combination are preferably selected. In general, the light emission illuminance of the light source used is preferably 50 to 2000 mW / cm ^{2 based on} a wavelength of 365 nm. Moreover, when the illuminance measurement in the vicinity of the maximum emission wavelength is possible, it is more preferable to expose in the illuminance range. When the illuminance is low, the time required for curing increases, which is not preferable from the viewpoint of productivity. On the other hand, when the illuminance is high, curing shrinkage is likely to occur, and the surface may have a skin-like defect or crack, or may peel at the interface with the adjacent layer.
Ionizing radiation is radiation that can ionize substances, and includes direct ionizing radiation represented by alpha rays and electron beams, and indirect ionizing radiation represented by X rays and neutron rays. It is done. The ionizing radiation that can be used in the present invention is not particularly limited as long as it is generally used, but in view of the influence on the human body, an electron beam is preferable. As an electron beam irradiation device, use a device using various electron beam accelerators such as a Cockloft Walton type, a bandegraph type, a resonant transformer type, an insulated core transformer type, or a linear type, a dynamitron type, a high frequency type, etc. Good. The irradiation amount of the electron beam may be appropriately determined according to the material to be used and the thickness of the cross-linked charge transport layer, but it is usually preferable to irradiate electrons having energy of 100 to 1000 keV, preferably 100 to 3000 keV, about 0.1 to 30 Mrad. . When the irradiation amount is less than 0.1 Mrad, the electron beam cannot reach the inside of the cross-linked charge transport layer, and there is a possibility that poor curing of the deep layer may occur. On the other hand, when the irradiation amount exceeds 30 Mrad, the electron beam may reach a charge transport layer and a charge generation layer, which will be described later, and may affect the constituent materials of each layer.

During UV irradiation or ionizing radiation irradiation, the temperature of the photoreceptor cross-linked charge transport layer rises due to the influence of heat rays generated from the light source. If the photoreceptor surface temperature rises too much, cure shrinkage of the crosslinkable charge transport layer is likely to occur, and low molecular components contained in the adjacent layer migrate to the crosslinkable charge transport layer, which may cause curing inhibition. In addition, the electrical characteristics as an electrophotographic photosensitive member are not preferable. Therefore, the photoreceptor surface temperature during UV irradiation is 100 ° C. or less, preferably 80 ° C. or less. As a cooling method, it is possible to use an auxiliary cooling agent inside the photosensitive member, cooling with a gas or liquid inside the photosensitive member, or the like.
You may post-heat with respect to the bridge | crosslinking type charge transport layer after hardening as needed. For example, in the case where a large amount of residual solvent remains in the film, it may cause a decrease in electrical characteristics or deterioration with time. Therefore, it is preferable to volatilize the residual solvent by post-heating.

The thickness of the cross-linked charge transport layer is preferably 1 to 15 μm, more preferably 3 to 10 μm from the viewpoint of protecting the photosensitive layer. When the crosslinkable charge transport layer is thin, not only can the photosensitive layer not be protected from mechanical abrasion due to a contact member to the photoreceptor or proximity discharge by a charger, etc., but it becomes difficult to level during film formation. The film surface may be distorted. On the other hand, when the crosslinkable charge transport layer is thick, the entire photoreceptor layer becomes thick, and the reproducibility of the image due to the diffusion of charges is not preferable. However, if the thickness of the cross-linked charge transport layer is greater than the thickness of the charge transport layer, the tendency of the bright part potential to increase is unfavorable. In the present invention, when the film thickness of the charge transport layer is T1 and the film thickness T2 of the crosslinkable charge transport layer, satisfying the relationship of the following formula (3) can suppress the influence thereof, which is more preferable.
T1> T2 × 2 Formula (3)

<About adhesive layer>
For the purpose of preventing delamination due to poor adhesion between the crosslinkable charge transport layer / photosensitive layer, an adhesive layer may be provided between the two layers as necessary.
As the adhesive layer, the radical polymerizable monomer may be used, or a non-crosslinked polymer compound may be used. Non-crosslinked polymer compounds include polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, polyacrylamide, and polyvinyl benzal. , Polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone and the like, but are not limited thereto. In addition, the radical polymerizable monomer and the non-crosslinked polymer compound may be used either alone or as a mixture of two or more. Furthermore, a radical polymerizable monomer and a non-crosslinked polymer compound may be used in combination as long as sufficient adhesiveness is obtained. Of course, the charge transport materials described in the present specification may be used or used in combination. Moreover, an additive may be appropriately used for the purpose of improving the adhesiveness.
The adhesive layer is formed by applying a coating solution prepared by dissolving or dispersing a compound formulated in a prescribed formulation in a solvent such as tetrahydrofuran, dioxane, dichloroethane, or cyclohexane by dip coating, spray coating, bead coating, or ring coating. it can. The thickness of the adhesive layer is suitably about 0.1 to 5 μm, preferably 0.1 to 3 μm is most suitable.

<About the undercoat layer>
In the photoreceptor of the present invention, an undercoat layer can be provided between the conductive support and the photosensitive layer. In general, the undercoat layer is mainly composed of a resin. However, considering that the photosensitive layer is coated with a solvent on these resins, the resin may be a resin having high solvent resistance with respect to a general organic solvent. desirable. Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. Further, a metal oxide fine powder pigment exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like may be added to the undercoat layer in order to prevent moire and reduce residual potential.
These undercoat layers can be formed using an appropriate solvent and a coating method like the above-mentioned photosensitive layer. Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the undercoat layer of the present invention. In addition, in the undercoat layer of the present invention, Al ₂ O ₃ is provided by anodization, organic substances such as polyparaxylylene (parylene), SiO ₂ , SnO ₂ , TiO ₂ , ITO, CeO ₂ A material provided with an inorganic material such as a vacuum thin film can also be used favorably. In addition, known ones can be used.
The thickness of the undercoat layer is suitably from 0 to 5 μm.

<About blocking layer>
It is also possible to further provide a blocking layer between the conductive support and the undercoat layer or between the undercoat layer and the charge generation layer. The blocking layer is added to suppress the injection of holes from the conductive support, and the main purpose is to suppress the soiling. In the blocking layer, a binder resin is generally used as a main component. Examples of these resins include polyamide, alcohol-soluble polyamide (soluble nylon), water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol. As a method for forming the blocking layer, the above-described method and a known coating method are employed. In addition, 0.05-2 micrometers is suitable for the thickness of a blocking layer. By adopting the two-layer configuration of the blocking layer and the undercoat layer, the background stain suppression effect is dramatically increased, but the influence of the residual potential increase tends to increase. Therefore, it is necessary to determine the composition and thickness of the blocking layer and the undercoat layer with sufficient consideration.

<Ionization potential measurement>
The ionization potential defined in the present invention means the amount of energy necessary to extract one electron from the ground state of the material.
In the present invention, a device (a surface analyzer manufactured by Riken Keiki Co., Ltd., AC-1, AC-2, AC-3) that measures the photoelectron spectrum emitted by irradiating ultraviolet rays in the air atmosphere is used. The ionization potential was obtained by irradiating ultraviolet light dispersed with a meter while changing the energy, and obtaining the minimum energy at which photoelectrons start to be emitted by the photoelectric effect. The ionization potential measured for these samples was taken as the ionization potential of the crosslinked charge transport layer.
A charge generation layer, a charge transport layer, and a cross-linked charge transport layer were formed on a smooth Al plate according to the formulation described later, and a sample for measuring ionization potential was prepared.
-Measurement conditions-
(1) Light quantity: 100 nw
(2) Energy range of incident light: 4.0 eV to 6.2 eV
(3) Unit photon: 1 × 10 ¹¹ [CPS]
(4) Measurement time: 10 sec
As long as it is obtained by the same principle as described above, it may not be measured by the above-mentioned apparatus and conditions.

The bright part potential increase is largely caused by charge traps in the interface between the charge generation layer and the charge transport layer, the interface between the charge transport layer and the cross-linked charge transport layer, or the bulk of the charge transport layer or the cross-linkable charge transport layer.
Among these charge trapping factors, the influence of the interface between the charge generation layer and the charge transport layer and the interface between the charge transport layer and the cross-linked charge transport layer is particularly large. Therefore, as one means for reducing the bright portion potential, it is effective to reduce the charge injection barrier by reducing the difference between the ionization potential of the charge transport material and the charge generation material contained in the charge transport layer.
In particular, since titanyl phthalocyanine pigments have a low ionization potential, a charge transport material having an ionization potential equal to or lower than that of titanyl phthalocyanine is used to reduce the light potential in a photoreceptor using the same as a charge generation material. Must be contained in the charge transport layer.

Further, when a protective layer is provided thereon, an increase in the bright portion potential is inevitable unless the ionization potential of the protective layer is equal to or lower than that of the charge transport layer. Therefore, conventionally, many configurations have been adopted in which the ionization potential of the layer on the outermost surface of the photoreceptor is lowest. However, it has been found that such a configuration has a side effect of causing image deletion when exposed to an oxidizing gas. Realizing simultaneously the reduction of the light potential and the suppression of image flow by the oxidizing gas, which are in a trade-off relationship, has been regarded as a major issue.
In the present invention, when the ionization potential of the charge generation layer is Ip (G), the ionization potential of the charge transport layer is Ip (T), and the ionization potential of the cross-linked charge transport layer is Ip (O), the following formula (1) ) And (2).
−0.16 ≦ Ip (T) −Ip (G) ≦ 0.07 (1)
0.07 <Ip (O) −Ip (G) ≦ 0.33 (2)

As a result, both high-potential rise suppression and image flow suppression due to oxidizing gas can be achieved, and image defects such as ghosts can be suppressed. As a result, a photoconductor with high durability was obtained.
When the value of Ip (T) −Ip (G) is smaller than −0.16, the charge injection barrier between the charge generation layer and the charge transport layer can be reduced, but the charge reduction is significantly increased. When the image is fogged, the resolution is lowered, or the oxidizing gas concentration is high, the image flow is likely to occur. In the present invention, the lower limit of Ip (T) -Ip (G) is −0.16, more preferably −0.1 or more.
When the value of Ip (T) -Ip (G) is larger than 0.07, the bright part potential is clearly increased, and the effect of suppressing the bright part potential rise cannot be sufficiently obtained. The photoconductor of the present invention is formed by forming a crosslinkable charge transport layer on the surface of which a radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a charge transport structure are cured. The influence of the partial potential increase is almost determined by the interface between the charge generation layer and the charge transport layer, and the influence of the charge trap at the interface between the charge transport layer and the cross-linked charge transport layer can be very small.
In the present invention, the upper limit of Ip (T) -Ip (G) is 0.07 or less, more preferably 0.04 or less.

When the value of Ip (O) -Ip (G) exceeds 0.33 Even if the difference between the ionization potential of the charge generation layer and the ionization potential of the charge transport layer satisfies the above range, the influence of the bright portion potential increase is large. This is not preferable. Even if the difference between the ionization potential of the charge transport layer and the ionization potential of the cross-linked charge transport layer is reduced, the difference between the ionization potential of the charge generation layer and the ionization potential of the charge transport layer is increased. Inevitable. Therefore, it is a necessary condition that the difference between the ionization potential of the cross-linked charge transport layer and the ionization potential of the charge generation layer is 0.33 or less. In the present invention, the upper limit of Ip (O) -Ip (G) is 0.33 or less, more preferably 0.27 or less.
When the value of Ip (O) −Ip (G) is 0.07 or less, image flow tends to occur. When a metal phthalocyanine pigment having a low ionization potential is used as the charge generation material, the ionization potential of the charge transport material contained in the layer formed on the outermost surface of the photoreceptor is inevitably low. Flow occurs. It is considered that when the surface of the photoreceptor is exposed to an oxidizing gas such as ozone generated by charging, the charge transport material contained in the photoreceptor surface is altered and the resistance is lowered. A charge transport material having a smaller ionization potential has a greater effect, and thus an image stream is generated by repeated use of the photoreceptor. If Ip (O) -Ip (G) is greater than 0.07, image flow is unlikely to occur and is not easily affected by oxidizing gas.

  In addition, in this invention, it prescribes | regulates by Formula (1) and Formula (2), and it does not mention in particular about the difference of Ip (O) and Ip (T). Even if the difference between Ip (O) and Ip (T) is defined, if a charge transport material having a low ionization potential reaching the lower limit of Ip (T) -Ip (G) is contained in the charge transport layer, Ip (T Even if Ip (O) is larger than), there is a possibility of causing the occurrence of an image stream. In the present invention, since the influence of the bright portion potential increase has an effect that does not largely depend on the difference between Ip (O) and Ip (T), the ionization potential of the cross-linked charge transport layer and the ionization of the charge generation layer By being defined by the difference from the potential, Ip (O) −Ip (G), it is possible to obtain an effect capable of realizing both the reduction of the bright portion potential and the suppression of the image flow.

<Protective substances>
A protective substance may be applied to the surface of the electrophotographic photosensitive member for the purpose of improving the cleaning property by reducing the surface energy of the electrophotographic photosensitive member and protecting it from electrical and mechanical hazards.
As the protective substance, various materials can be used as long as they can be uniformly applied to the surface of the electrophotographic photosensitive member, but materials such as wax, silicone oil, and fatty acid salt are effective. Fatty acid salts are particularly effective because they can be applied uniformly to a thin layer on the surface of the photoreceptor without causing deterioration of the electrical characteristics of the electrophotographic photoreceptor. Examples of fatty acids include undecyl acid, lauric acid, tridecyl acid, myristic acid, palmitic acid, pendadecyl acid, stearic acid, heptadecyl acid, arachidic acid, montanic acid, oleic acid, arachidonic acid, caprylic acid, capric acid, caproic acid, etc. Examples of the metal salt include salts with metals such as zinc, iron, copper, magnesium, aluminum, and calcium.
Furthermore, it is preferable to use a lamellar crystal powder such as zinc stearate as a protective substance. A lamellar crystal has a layered structure in which amphiphilic molecules are self-organized, and when a shearing force is applied, the crystal breaks along the layers and is slippery. This action is effective for lowering the coefficient of friction, but when viewed from the viewpoint of protecting the photoreceptor surface from discharge, the characteristics of lamellar crystals that uniformly cover the photoreceptor surface under shearing force are as follows: Since the surface of the photoreceptor can be effectively covered with a small amount of protective material, it is desirable as a protective material.
The method for applying the protective substance is not particularly limited, and examples thereof include a method in which a protective substance is previously applied to a member such as a cleaning member that contacts the photosensitive member, and a method in which a dedicated application member is integrated with the process cartridge. . Providing a dedicated application member is preferable because a stable amount can be applied over a long period of time.

<< Regarding Configuration of Image Forming Apparatus >>
Next, the image forming apparatus of the present invention will be described in detail with reference to the drawings.
The image forming apparatus of the present invention uses the electrophotographic photosensitive member having the cross-linked charge transport layer of the present invention. ) And a means for fixing and cleaning the surface of the photoreceptor, if necessary.
In some cases, an image forming apparatus that directly transfers an electrostatic latent image to a transfer body and develops the image forming apparatus does not necessarily include the above-described means disposed on the photoreceptor.
FIG. 2 is a schematic diagram illustrating an example of an image forming apparatus. A charging charger (3) is used as a means for charging the photoconductor on average. As the charging means, a corotron device, a scorotron device, a solid discharge element, a needle electrode device, a roller charging device, a conductive brush device, or the like is used, and a known system can be used.
Next, the image exposure unit (5) is used to form an electrostatic latent image on the uniformly charged photoreceptor (1). As the light source, all luminescent materials such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL) can be used. Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.

Next, the developing unit (6) is used to visualize the electrostatic latent image formed on the photoreceptor (1). Development methods include a one-component development method using a dry toner, a two-component development method, and a wet development method using a wet toner. When the photosensitive member is positively (negatively) charged and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. A positive image can be obtained by developing this with negative (positive) toner (electrodetection fine particles), and a negative image can be obtained by developing with positive (negative) toner.
Next, a transfer charger (10) is used to transfer the toner image visualized on the photoconductor onto the transfer body (9). In addition, a pre-transfer charger (7) may be used for better transfer. As these transfer means, a transfer charger, an electrostatic transfer method using a bias roller, a mechanical transfer method such as an adhesive transfer method and a pressure transfer method, and a magnetic transfer method can be used. As the electrostatic transfer method, the charging means can be used.
Next, a separation charger (11) and a separation claw (12) are used as means for separating the transfer body (9) from the photoreceptor (1). As other separation means, electrostatic adsorption induction separation, side end belt separation, tip grip conveyance, curvature separation, and the like are used. As the separation charger (11), the charging means can be used.

Next, a fur brush (14) and a cleaning blade (15) are used to clean the toner remaining on the photoreceptor after transfer. Further, a pre-cleaning charger (13) may be used in order to perform cleaning more efficiently. Other cleaning means include a web method, a magnet brush method, and the like, but each may be used alone or in combination. Next, a neutralizing unit is used for the purpose of removing the latent image on the photoreceptor as required. As the charge removal means, a charge removal lamp (2) and a charge removal charger are used, and the exposure light source and the charging means can be used respectively. In FIG. 2, 4 is an eraser, and 8 is a registration roller.
In addition, known means can be used for reading, feeding, fixing, and discharging the document that are not close to the photosensitive member.
The present invention also relates to an image forming method and an image forming apparatus process cartridge using the electrophotographic photoreceptor according to the present invention for such image forming means.
The image forming means may be fixedly incorporated in a copying apparatus, facsimile, or printer, but may be incorporated in these apparatuses in the form of a process cartridge and detachable. An example of the process cartridge is shown in FIG.
The process cartridge for the image forming apparatus includes a photoreceptor (101), and in addition, a charging unit (102), a developing unit (104), a transfer unit (106), a cleaning unit (107), and a discharging unit (not shown). ), And an apparatus (part) that can be attached to and detached from the image forming apparatus main body.

  Referring to the image forming method using the apparatus illustrated in FIG. 3, the surface of the photoconductor (101) is exposed by charging by the charging means (102) and exposure by the exposure means (103) while rotating in the direction of the arrow. An electrostatic latent image corresponding to the image is formed, and the electrostatic latent image is developed with toner by the developing means (104). The toner development is transferred to the transfer body (105) by the transfer means (106), and printed. Be out. Next, the surface of the photoconductor after the image transfer is cleaned by a cleaning unit (107), and further neutralized by a neutralizing unit (not shown), and the above operation is repeated again.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to a following example. Parts and% are based on weight.
First, a synthesis example of a charge generation material (titanyl phthalocyanine crystal) will be described.
(Synthesis Example 1)
(Synthesis of titanyl phthalocyanine crystal)
First, a method for synthesizing the titanyl phthalocyanine crystal used in the present invention will be described. The synthesis was in accordance with Japanese Patent Application Laid-Open No. 2004-83859. That is, 292 parts of 1,3-diiminoisoindoline and 1800 parts of sulfolane are mixed, and 204 parts of titanium tetrabutoxide are added dropwise under a nitrogen stream. After completion of the dropwise addition, the temperature was gradually raised to 180 ° C., and the reaction was carried out by stirring for 5 hours while maintaining the reaction temperature between 170 ° C. and 180 ° C. After the reaction is complete, the mixture is allowed to cool, and then the precipitate is filtered, washed with chloroform until the powder turns blue, then washed several times with methanol, then washed several times with hot water at 80 ° C. and dried. Crude titanyl phthalocyanine was obtained. Crude titanyl phthalocyanine is dissolved in 20 times the amount of concentrated sulfuric acid, added dropwise to 100 times the amount of ice water with stirring, the precipitated crystals are filtered, and then ion-exchanged water (pH: 7. 0, specific conductivity: 1.0 μS / cm) Repeated washing with water (pH value of ion-exchanged water after washing was 6.8, specific conductivity was 2.6 μS / cm), wet of titanyl phthalocyanine pigment A cake (water paste) was obtained.

40 parts of the obtained wet cake (water paste) was put into 200 parts of tetrahydrofuran and stirred vigorously (2000 rpm) with a homomixer (Kennis, MARKIIf model) at room temperature, and the dark blue color of the paste turned pale blue When changed (20 minutes after the start of stirring), stirring was stopped and filtration under reduced pressure was immediately performed. The crystals obtained on the filter were washed with tetrahydrofuran to obtain a pigment wet cake. This was dried under reduced pressure (5 mmHg) at 70 ° C. for 2 days to obtain 8.5 parts of titanyl phthalocyanine crystals. The solid content concentration of the wet cake was 15% by mass. The crystal conversion solvent was used in a mass ratio of 33 times that of the wet cake. In addition, the halogen-containing compound is not used for the raw material of the synthesis example 1. When the obtained titanyl phthalocyanine powder was subjected to X-ray diffraction spectrum measurement under the following conditions, the Bragg angle 2θ with respect to CuKα ray (wavelength 1.542１．５) was 27.2 ± 0.2 °, and the maximum peak and the minimum angle 7.3. It has a peak at ± 0.2 °, and further has major peaks at 9.4 ± 0.2 °, 9.6 ± 0.2 °, 24.0 ± 0.2 °, and 7.3 A titanyl phthalocyanine powder having no peak between the peak at 0 ° and the peak at 9.4 ° and further having no peak at 26.3 ° was obtained. The result is shown in FIG.
<X-ray diffraction spectrum measurement conditions>
X-ray tube: Cu
Voltage: 50kV
Current: 30mA
Scanning speed: 2 ° / min Scanning range: 3 ° -40 °
Time constant: 2 seconds

(Synthesis Example 2)
In accordance with Japanese Patent No. 3166293, Synthesis Examples and Example 1, hydroxygallium phthalocyanine was synthesized.
That is, 30 parts of 1,3-diiminoisoindoline and 9.1 parts of gallium trichloride were added to 230 parts of quinoline and reacted at 200 ° C. for 3 hours, and then the product was filtered off. Subsequently, it was washed with acetone and methanol, and the wet cake was dried to obtain 28 parts of chlorogallium phthalocyanine crystals.
Subsequently, 3 parts of the chlorogallium phthalocyanine crystal was dissolved in 60 parts of concentrated sulfuric acid at 0 ° C., and then this solution was dropped into 450 parts of distilled water at 5 ° C. to precipitate a crystal. After washing with distilled water, dilute ammonia water or the like, it was dried to obtain 2.5 parts of hydroxygallium phthalocyanine crystal. Further, 0.5 parts of the hydroxygallium phthalocyanine crystal was milled for 24 hours together with 15 parts of dimethylformamide and 30 parts of glass beads having a diameter of 1 mm, and then the crystals were separated. Subsequently, it was washed with methanol and dried to obtain a target hydroxygallium phthalocyanine crystal.
When the obtained hydroxygallium phthalocyanine crystal was subjected to X-ray diffraction spectrum measurement under the same conditions as in Synthesis Example 1, the Bragg angle 2θ with respect to CuKα ray (wavelength 1.542Å) was 7.5 °, 9.9 °, 12.5 It had strong diffraction peaks at °, 16.3 °, 18.6 °, 25.1 ° and 28.3 °. The obtained spectrum was the same as the X-ray diffraction spectrum described in Japanese Patent No. 3166293 and FIG.

(Synthesis Example 3)
Chlorogallium phthalocyanine was synthesized according to Japanese Patent No. 3123185, Synthesis Example and Example 2.
That is, 30 parts of 1,3-diiminoisoindoline and 9.1 parts of gallium trichloride are added to 230 parts of quinoline and reacted at 200 ° C. for 3 hours, and then the product is filtered and washed with acetone and methanol. did. Next, the wet cake was dried to obtain chlorogallium phthalocyanine crystals. This chlorogallium phthalocyanine crystal is dry-ground in an automatic mortar for 3 hours, and further 0.5 part of chlorogallium phthalocyanine is mixed with 60 parts of 1 mmφ glass beads at room temperature in 20 parts of a mixed solvent of water / chlorobenzene 1:10. After ball milling for 24 hours, it was filtered off, washed with 10 parts of methanol and dried to obtain chlorogallium phthalocyanine crystals.
The obtained chlorogallium phthalocyanine crystal was subjected to X-ray diffraction spectrum measurement under the same conditions as in Synthesis Example 1. As a result, the Bragg angle 2θ with respect to CuKα ray (wavelength 1.542Å) was 7.4 °, 16.6 °, 25.5. It had strong diffraction peaks at ° and 28.3 °. The obtained spectrum was the same as the X-ray diffraction spectrum described in Japanese Patent No. 3123185 and FIG.

(Synthesis Example 4)
X-type metal-free phthalocyanine was synthesized in accordance with JP 2001-247786 A, Synthesis Examples and Example 1.
That is, 100 parts of o-phthalodinitrile and 10 parts of piperidine were reacted in 300 parts of chlorotoluene with stirring at 200 ° C. for 10 hours to obtain reddish purple crystals. Subsequently, each was washed with an acid and an alkali, then washed with methanol, N, N-dimethylformamide and N-methylpyrrolidone, and then dried to obtain a crude metal-free phthalocyanine. After 12 parts of the obtained crude metal-free phthalocyanine was sufficiently dissolved in 200 parts of sulfuric acid (concentration 97%) cooled to 0 to 5 ° C. and dropped into 2000 parts of pure water to cause reprecipitation, The mixture was filtered, further washed with alkali, methanol, N, N-dimethylformamide, and N-methylpyrrolidone, and then dried to obtain 10 parts of α-type metal-free phthalocyanine pigment. Ten parts of the α-type metal-free phthalocyanine pigment thus obtained were pulverized with a magnetic ball mill for 4 days together with 0.5 parts of the X-type metal-free phthalocyanine pigment to obtain an X-type metal-free phthalocyanine pigment.
Next, 5 parts of the X-type metal-free phthalocyanine pigment was put into an alumina pot together with 50 parts of 5 mmφ zirconia beads. This was mounted on a small vibration mill (MB-0 type, manufactured by Chuo Kako Co., Ltd.), and dry pulverized for 5 minutes. The powder X-ray diffraction pattern of the obtained X-type metal-free phthalocyanine pigment was measured by X-ray diffraction spectrum under the same conditions as in JP-A-2001-247786 and Synthesis Example 1, and described in JP-A-2001-247786 and FIG. It was the same as the X-ray diffraction spectrum of.

(Synthesis Example 5)
Next, a synthesis example of a compound having a monofunctional charge transporting structure used for a cross-linked charge transport layer in a photoreceptor preparation example described later will be described.
(Synthesis example of a compound having a monofunctional charge transporting structure)
The compound having a monofunctional charge transport structure in the present invention is synthesized, for example, by the method described in Japanese Patent No. 3164426. An example of this is shown below.
(1) Synthesis of hydroxy group-substituted triarylamine compound (following formula B) 113.85 parts (0.3 mol) of methoxy group substituted triarylamine compound (following formula A) and 138 parts (0.92 mol) of sodium iodide To this, 240 parts of sulfolane was added and heated to 60 ° C. in a nitrogen stream. In this liquid, 99 parts (0.91 mol) of trimethylchlorosilane was added dropwise over 1 hour and stirred at a temperature of about 60 ° C. for 4 and a half hours to complete the reaction.
About 1500 parts of toluene was added to the reaction solution, cooled to room temperature, and washed repeatedly with water and an aqueous sodium carbonate solution.
Thereafter, the solvent was removed from the toluene solution, and purification was performed by column chromatography (adsorption medium: silica gel, developing solvent: toluene: ethyl acetate = 20: 1).
Cyclohexane was added to the obtained pale yellow oil to precipitate crystals.
In this way, 88.1 parts (yield = 80.4%) of white crystals of the following formula B were obtained.
Melting point: 64.0-66.0 ° C

(2) Triarylamino group-substituted acrylate compound (Exemplary Compound No. 54) 82.9 parts (0.227 mol) of the hydroxy group-substituted triarylamine compound (Formula B) obtained in (1) above is dissolved in 400 ml of tetrahydrofuran. Then, an aqueous sodium hydroxide solution (NaOH: 12.4 parts, water: 100 ml) was added dropwise in a nitrogen stream. The solution was cooled to 5 ° C., and 25.2 parts (0.272 mol) of acrylic acid chloride was added dropwise over 40 minutes. Then, it stirred at 5 degreeC for 3 hours, and reaction was complete | finished. The reaction solution was poured into water and extracted with toluene. This extract was repeatedly washed with an aqueous sodium bicarbonate solution and water. Thereafter, the solvent was removed from the toluene solution, and purification was performed by column chromatography (adsorption medium: silica gel, developing solvent: toluene). N-Hexane was added to the obtained colorless oil to precipitate crystals. In this way, Exemplified Compound No. 54.73 parts of white crystals (yield = 84.8%) were obtained.
Melting point: 117.5-119.0 ° C

<Ionization potential measurement sample>
One of a charge generation layer, a charge transport layer, and a cross-linked charge transport layer was formed on a smooth aluminum plate, and a sample for measuring ionization potential was produced. In addition, a part of the film was measured by cutting out the film from the surface of the photoconductor, and it was confirmed that it coincided with the measurement result obtained by forming on the aluminum plate. The ionization potential was measured five times while changing the measurement location of the sample, and the average value was adopted.
Next, examples using an electrophotographic photosensitive member obtained by using the material obtained by the above method will be described.
<Example 1>
An undercoat layer coating solution, a charge generation layer coating solution, a charge transport layer coating solution, and a crosslinkable charge transport layer coating solution are sequentially applied to an aluminum cylinder having a diameter of 100 mm as a conductive support. The substrate was dried to form an undercoat layer of about 3.5 μm, a charge generation layer of about 0.2 μm, a charge transport layer of about 23 μm, and a cross-linked charge transport layer of about 5 μm to produce a laminated photoreceptor. After the coating of each layer, touch drying was performed, and then the undercoat layer was dried at 130 ° C., the charge generation layer was 95 ° C., and the charge transport layer was dried at 120 ° C. for 20 minutes.
The crosslinkable charge transport layer is formed by applying a crosslinkable charge transport layer coating solution onto a laminated photoreceptor composed of the conductive support / undercoat layer / charge generation layer / charge transport layer and then applying a UV lamp (bulb type H bulb). ) (Manufactured by Fusion UV Systems Co., Ltd.) and crosslinked by light irradiation under the conditions of a lamp output of 200 W / cm, illuminance: 450 mW / cm ² , and irradiation time: 30 seconds. Thereafter, drying was performed at 130 ° C. for 20 minutes to obtain an electrophotographic photosensitive member comprising a conductive support / undercoat layer / charge generation layer / charge transport layer / crosslinked charge transport layer.

(Coating liquid for undercoat layer)
Titanium oxide (CR-EL, average primary particle size: about 0.25 μm, manufactured by Ishihara Sangyo Co., Ltd.): 50 parts Alkyd resin (Beckolite M6401-50, solid content: 50%, Dainippon Ink & Chemicals, Inc.) Manufactured): 14 parts melamine resin (L-145-60, solid content: 60%, manufactured by Dainippon Ink & Chemicals, Inc.): 8 parts 2-butanone: 70 parts [coating liquid for charge generation layer]
The titanyl phthalocyanine crystal prepared in Synthesis Example (1) was dispersed under the following composition with the following composition to prepare a charge generation layer coating solution.
Titanyl phthalocyanine crystal 15 parts Polyvinyl butyral (manufactured by Sekisui Chemical Co., Ltd .: BX-1) 10 parts 2-butanone 280 parts 2-butanone solution in which polyvinyl butyral is dissolved using PSZ balls having a diameter of 0.5 mm in a commercially available bead mill disperser and the above Pigment was added and the rotor rotation speed was 1200 r. p. m. For 30 minutes to prepare a charge generation layer coating solution.
The film thickness of the charge generation layer was adjusted so that the transmittance of the charge generation layer at 780 nm was 25%. The transmittance of the charge generation layer is the same as that of the photoconductor production on the aluminum cylinder wound with a polyethylene terephthalate film, and the charge generation layer coating solution having the following composition is applied to the polyethylene without applying the charge generation layer. Using the terephthalate film as a comparative control, the transmittance at 780 nm was evaluated with a commercially available spectrophotometer (Shimadzu: UV-3100).

[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
Low molecular charge transport material of the following formula: 10 parts Tetrahydrofuran 80 parts 1% silicone oil tetrahydrofuran solution 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

[Coating liquid for cross-linked charge transport layer]
10 parts of radically polymerizable monomer having no charge transport structure Trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
10 parts of radically polymerizable compound having a charge transporting structure (Exemplary Compound No. 54)
Photopolymerization initiator 1 part (1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals))
Tetrahydrofuran 100 parts

<Example 2>
An electrophotographic photosensitive member was produced in the same manner as in Example 2 except that the radical polymerizable monomer having no charge transporting structure contained in the coating liquid for the crosslinkable charge transporting layer of Example 1 was replaced with the following monomer. did.
Pentaerythritol tetraacrylate (SR-295, manufactured by Kayaku Sartomer)
Molecular weight: 352, number of functional groups: 4 functions, molecular weight / number of functional groups = 88

<Example 3>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge generation material in the charge generation layer coating solution of Example 1 was replaced with chlorogallium phthalocyanine in Synthesis Example (3).

<Example 4>
A radical polymerizable compound having a charge transporting structure contained in the coating liquid for a crosslinkable charge transport layer, wherein the charge generation material of the charge generation layer coating liquid of Example 1 is changed to hydroxygallium phthalocyanine of Synthesis Example (2) An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that was replaced with the following compound.

<Example 5>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport material contained in the coating solution for charge transport layer of Example 1 was replaced with the following compound.

<Example 6>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport material contained in the coating solution for charge transport layer of Example 1 was replaced with the following compound.

<Example 7>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport material contained in the coating solution for charge transport layer of Example 1 was replaced with the following compound.

<Example 8>
The charge generating material of the charge generation layer coating solution of Example 7 is changed to the chlorogallium phthalocyanine of Synthesis Example (3), and the radical polymerizable property having a charge transporting structure contained in the crosslinking type charge transport layer coating solution An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the compound was changed to the following compound.

<Example 9>
An electrophotographic photosensitive member was produced in the same manner as in Example 3 except that the charge transport material contained in the charge transport layer coating solution of Example 3 was replaced with the following compound.

<Example 10>
An electrophotographic photosensitive member was produced in the same manner as in Example 4 except that the charge transport material contained in the charge transport layer coating solution of Example 4 was replaced with the following compound.

<Example 11>
An electrophotographic photosensitive member was produced in the same manner as in Example 9, except that the charge transport material contained in the charge transport layer coating solution of Example 9 was replaced with the following compound.

<Example 12>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer coating solution and the crosslinked charge transport layer coating solution of Example 1 were changed to the following compositions.
[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
Charge transport material of the following formula: 10 parts Tetrahydrofuran 80 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

[Coating liquid for cross-linked charge transport layer]
10 parts of radically polymerizable monomer having no charge transport structure 6-hexanediol diacrylate (manufactured by Wako Pure Chemical Industries, Ltd.)
Molecular weight: 226, number of functional groups: bifunctional, molecular weight / number of functional groups = 113
10 parts of radically polymerizable compound having a charge transporting structure (Exemplary Compound No. 157)
1 part of photopolymerization initiator (1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals))
Tetrahydrofuran 100 parts

<Example 13>
An electrophotographic photosensitive member was produced in the same manner as in Example 12 except that the radical polymerizable monomer having no charge transporting structure contained in the coating liquid for the crosslinkable charge transporting layer of Example 12 was replaced with the following monomer. did.
Radical polymerizable monomer without charge transporting structure Dipentaerythritol caprolactone modified hexaacrylate (KAYARAD DPCA-120, Nippon Kayaku)
Molecular weight: 1947, number of functional groups: 6 functions, molecular weight / number of functional groups = 325

<Example 14>
An electrophotographic photosensitive member was produced in the same manner as in Example 12 except that the radical polymerizable monomer having no charge transporting structure contained in the coating liquid for the crosslinkable charge transporting layer of Example 12 was replaced with the following monomer. did.
Trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99

<Example 15>
An electrophotographic photosensitive member was produced in the same manner as in Example 14 except that the radical polymerizable compound having a charge transporting structure contained in the coating liquid for the crosslinked charge transport layer of Example 14 was replaced with the following compound.

<Example 16>
An electrophotographic photosensitive member was produced in the same manner as in Example 14 except that the radical polymerizable compound having a charge transporting structure contained in the coating liquid for the crosslinked charge transport layer of Example 14 was replaced with the following compound.

<Example 17>
An electrophotographic photosensitive member was produced in the same manner as in Example 14 except that the radical polymerizable compound having a charge transporting structure contained in the coating solution for the crosslinkable charge transport layer of Example 14 was replaced with the following compound.

<Example 18>
An electrophotographic photosensitive member was produced in the same manner as in Example 14 except that the radical polymerizable compound having a charge transporting structure contained in the coating liquid for the crosslinked charge transport layer of Example 14 was replaced with the following compound.
Radical polymerizable compound having charge transporting structure (Exemplary Compound No. 54)

<Example 19>
The charge generation material of the charge generation layer coating solution of Example 18 was changed to the chlorogallium phthalocyanine of Synthesis Example (3), and the charge transport material contained in the charge transfer layer coating solution was changed to the following compounds. An electrophotographic photosensitive member was produced in the same manner as in Example 18.

<Example 20>
An electrophotographic photosensitive member was produced in the same manner as in Example 18 except that the charge transport material contained in the charge transport layer coating solution of Example 18 was changed to the following compound.
<Example 21>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the thickness of the charge transport layer in Example 1 was 19.0 μm and the thickness of the cross-linked charge transport layer was 10.3 μm.

<Example 22>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the thickness of the charge transport layer in Example 1 was 20.1 μm and the thickness of the cross-linked charge transport layer was 8.5 μm.
<Example 23>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport material contained in the coating solution for charge transport layer of Example 1 was replaced with the following compound.

<Example 24>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer coating solution of Example 1 was changed to the following composition.
[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
10 parts low molecular charge transport material of the formula
1 part of the following compound
Tetrahydrofuran 84 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

<Example 25>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer coating solution of Example 1 was changed to the following composition.
[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
10 parts low molecular charge transport material of the formula
1 part of the following compound
Tetrahydrofuran 84 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

<Example 26>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer coating solution of Example 1 was changed to the following composition.
[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
10 parts low molecular charge transport material of the formula
1 part of the following compound
Tetrahydrofuran 84 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

<Example 27>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer coating solution of Example 1 was changed to the following composition.
[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
10 parts low molecular charge transport material of the formula
Compound of the following structure Sanol LS2626 Sankyo 0.5 parts
Tetrahydrofuran 82 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

<Example 28>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer coating solution of Example 1 was changed to the following composition.
[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
10 parts low molecular charge transport material of the formula

Compound with the following structure BHT, manufactured by Kanto Chemical Co., 0.5 part
Tetrahydrofuran 82 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

<Example 29>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the coating liquid for the crosslinked charge transport layer in Example 1 was changed to the following composition.
[Coating liquid for cross-linked charge transport layer]
Radical polymerizable monomer having no charge transport structure 10 parts Trimethylolpropane triacrylate (KAYARAD
(TMPTA, Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
10 parts of radically polymerizable compound having a charge transporting structure (Exemplary Compound No. 54)
Photopolymerization initiator 1 part (1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals))
Alumina (average primary particle size: 0.3 μm, Sumiko Random AA03, manufactured by Sumitomo Chemical) 2 parts Tetrahydrofuran 100 parts

<Example 30>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the coating liquid for the crosslinked charge transport layer in Example 1 was changed to the following composition.
[Coating liquid for cross-linked charge transport layer]
Radical polymerizable monomer having no charge transport structure 10 parts Trimethylolpropane triacrylate (KAYARAD
(TMPTA, Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
10 parts of radically polymerizable compound having a charge transporting structure (Exemplary Compound No. 54)
Photopolymerization initiator 1 part (1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals))
Alumina (average primary particle size: 0.5 μm, Sumiko Random AA05, manufactured by Sumitomo Chemical) 2 parts Tetrahydrofuran 100 parts

<Example 31>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer coating solution of Example 1 was changed to the following composition.
[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
10 parts low molecular charge transport material of the formula
1 part of the following compound
Compound of the following structure Sanol LS2626 Sankyo 0.5 parts
Tetrahydrofuran 86 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

<Example 32>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer coating solution of Example 1 was changed to the following composition.
[Coating liquid for charge transport layer]
Bisphenol Z 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
10 parts low molecular charge transport material of the formula
1 part of the following compound
Compound of the following structure Sanol LS2626 Sankyo 0.5 parts
Tetrahydrofuran 86 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

<Example 33>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer coating solution of Example 1 was changed to the following composition.
[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
10 parts low molecular charge transport material of the formula
1 part of the following compound
Compound of the following structure Sanol LS2626 Sankyo 0.5 parts
Tetrahydrofuran 86 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

<Example 34>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer coating solution of Example 1 was changed to the following composition.
[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
10 parts low molecular charge transport material of the formula
1 part of the following compound
Compound with the following structure BHT, manufactured by Kanto Chemical Co., 0.5 part
Tetrahydrofuran 86 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

<Example 35>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer coating solution of Example 1 was changed to the following composition.
[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
10 parts low molecular charge transport material of the formula
1 part of the following compound
Compound with the following structure BHT, manufactured by Kanto Chemical Co., 0.5 part
Tetrahydrofuran 86 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

<Example 36>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer coating solution of Example 1 was changed to the following composition.
[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
10 parts low molecular charge transport material of the formula
1 part of the following compound
Compound with the following structure BHT, manufactured by Kanto Chemical Co., 0.5 part
Tetrahydrofuran 86 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

<Example 37>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer coating solution and the crosslinkable charge transport layer coating solution in Example 1 were changed to the following compositions.
[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
10 parts low molecular charge transport material of the formula
1 part of the following compound
Compound of the following structure Sanol LS2626 Sankyo 0.5 parts
Tetrahydrofuran 86 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)
[Coating liquid for cross-linked charge transport layer]
Radical polymerizable monomer having no charge transport structure 10 parts Trimethylolpropane triacrylate (KAYARAD
(TMPTA, Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
10 parts of radically polymerizable compound having a charge transporting structure (Exemplary Compound No. 54)
Photopolymerization initiator 1 part (1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals))
Alumina (average primary particle size: 0.3 μm, manufactured by Sumitomo Chemical) 2 parts Tetrahydrofuran 100 parts

<Example 38>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer coating solution and the crosslinkable charge transport layer coating solution in Example 1 were changed to the following compositions.
[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
10 parts low molecular charge transport material of the formula
1 part of the following compound
Compound of the following structure Sanol LS2626 Sankyo 0.5 parts
Tetrahydrofuran 86 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)
[Coating liquid for cross-linked charge transport layer]
Radical polymerizable monomer having no charge transport structure 10 parts Trimethylolpropane triacrylate (KAYARAD
(TMPTA, Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
10 parts of radically polymerizable compound having a charge transporting structure (Exemplary Compound No. 54)
Photopolymerization initiator 1 part (1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals))
Alumina (average primary particle size: 0.3 μm, manufactured by Sumitomo Chemical) 2 parts Tetrahydrofuran 100 parts

<Example 39>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer coating solution and the crosslinkable charge transport layer coating solution in Example 1 were changed to the following compositions.
[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
10 parts low molecular charge transport material of the formula
1 part of the following compound
Compound of the following structure Sanol LS2626 Sankyo 0.5 parts
Tetrahydrofuran 86 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)
[Coating liquid for cross-linked charge transport layer]
Radical polymerizable monomer having no charge transport structure 10 parts Trimethylolpropane triacrylate (KAYARAD
(TMPTA, Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
10 parts of radically polymerizable compound having a charge transporting structure (Exemplary Compound No. 54)
Photopolymerization initiator 1 part (1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals))
Alumina (average primary particle size: 0.3 μm, manufactured by Sumitomo Chemical) 2 parts Tetrahydrofuran 100 parts

<Example 40>
An electrophotographic photosensitive member was produced in the same manner as in Example 39 except that the charge generation material in the charge generation layer coating solution of Example 39 was replaced with hydroxygallium phthalocyanine in Synthesis Example (2).
<Example 41>
An electrophotographic photosensitive member was produced in the same manner as in Example 39 except that the charge generation material in the charge generation layer coating solution of Example 39 was replaced with chlorogallium phthalocyanine in Synthesis Example (3).

<Example 42>
An electrophotographic photosensitive member was produced in the same manner as in Example 39 except that the charge transport material in the charge transport layer of Example 39 was changed to the following compound.

<Example 43>
An electrophotographic photoreceptor was produced in the same manner as in Example 40 except that the charge transport material in the charge transport layer of Example 40 was changed to the following compound.
<Example 44>
An electrophotographic photosensitive member was produced in the same manner as in Example 41 except that the charge transport material in the charge transport layer of Example 41 was changed to the following compound.

<Example 45>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer coating solution of Example 1 was changed to the following composition.
[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
10 parts low molecular charge transport material of the formula
1 part of the following compound
Tetrahydrofuran 84 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

<Example 46>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer coating solution of Example 1 was changed to the following composition.
[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
10 parts low molecular charge transport material of the formula
1 part of the following compound
Compound of the following structure Sanol LS2626 Sankyo 0.5 parts
Tetrahydrofuran 86 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

<Example 47>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer coating solution and the crosslinkable charge transport layer coating solution in Example 1 were changed to the following compositions.
[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
10 parts low molecular charge transport material of the formula
1 part of the following compound
Compound of the following structure Sanol LS2626 Sankyo 0.5 parts
Tetrahydrofuran 86 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)
[Coating liquid for cross-linked charge transport layer]
Radical polymerizable monomer having no charge transport structure 10 parts Trimethylolpropane triacrylate (KAYARAD
(TMPTA, Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
10 parts of radically polymerizable compound having a charge transporting structure (Exemplary Compound No. 54)
Photopolymerization initiator 1 part (1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals))
Alumina (average primary particle size: 0.3 μm, manufactured by Sumitomo Chemical) 2 parts Tetrahydrofuran 100 parts

<Example 48>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the radical polymerizable compound having a charge transporting structure contained in the coating liquid for a crosslinkable charge transport layer of Example 1 was replaced with the following compound.

<Example 49>
An electrophotographic photosensitive member was produced in the same manner as in Example 33 except that the radical polymerizable compound having a charge transporting structure contained in the coating liquid for a crosslinkable charge transport layer in Example 33 was replaced with the following compound.

<Example 50>
An electrophotographic photosensitive member was produced in the same manner as in Example 29 except that the radical polymerizable compound having a charge transporting structure contained in the coating liquid for a crosslinkable charge transport layer in Example 29 was replaced with the following compound.

<Example 51>
An electrophotographic photosensitive member was produced in the same manner as in Example 42, except that the radical polymerizable compound having a charge transporting structure contained in the coating liquid for the crosslinked charge transport layer of Example 42 was replaced with the following compound.

<Comparative Example 1>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the radical polymerizable compound having a charge transporting structure contained in the coating liquid for a crosslinkable charge transport layer of Example 1 was replaced with the following compound.

<Comparative Example 2>
An electrophotographic photosensitive member was produced in the same manner as in Example 5 except that the charge generation material in the charge generation layer coating solution of Example 5 was replaced with chlorogallium phthalocyanine in Synthesis Example (3).

<Comparative Example 3>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 2, except that the radical polymerizable compound having a charge transporting structure contained in the coating liquid for the crosslinked charge transport layer of Comparative Example 2 was replaced with the following compound.

<Comparative example 4>
An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the charge generation material in the charge generation layer coating solution of Example 7 was replaced with the X-type metal-free phthalocyanine of Synthesis Example (4).

<Comparative Example 5>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 4 except that the radical polymerizable compound having a charge transporting structure contained in the coating liquid for the crosslinked charge transport layer of Comparative Example 4 was replaced with the following compound.

<Comparative Example 6>
An electrophotographic photosensitive member was produced in the same manner as in Example 9, except that the charge generation material in the charge generation layer coating solution of Example 9 was changed to titanyl phthalocyanine in Synthesis Example (1).

<Comparative Example 7>
An electrophotographic photosensitive member was produced in the same manner as in Example 9 except that the radical polymerizable compound having a charge transporting structure contained in the coating liquid for the crosslinkable charge transport layer of Example 9 was replaced with the following compound.

<Comparative Example 8>
An electrophotographic photosensitive member was produced in the same manner as in Example 19 except that the charge generation material in the charge generation layer coating solution of Example 19 was changed to titanyl phthalocyanine in Synthesis Example (1).
<Comparative Example 9>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the composition of the coating liquid for the crosslinkable charge transport layer in Example 1 was changed to the following.
20 parts of radically polymerizable compound having a charge transporting structure (Exemplary Compound No. 54)
Photopolymerization initiator 1 part (1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals))
Tetrahydrofuran 100 parts

<Comparative Example 10>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the composition of the coating liquid for the crosslinkable charge transport layer in Example 1 was changed to the following.
20 parts of trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
Photopolymerization initiator 1 part (1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals))
Tetrahydrofuran 100 parts

<Comparative Example 11>
The composition of the coating solution for the crosslinkable charge transport layer is not included without including the radical polymerizable monomer having no charge transporting structure contained in the coating solution for the crosslinkable charge transport layer of Example 1. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except for the change.
Bisphenol Z polycarbonate (Panlite TS-2050, manufactured by Teijin Chemicals) 10 parts Radical polymerizable compound having a charge transporting structure 10 parts (Exemplary Compound No. 54)
Photopolymerization initiator 1 part (1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals))
Tetrahydrofuran 100 parts

<Comparative Example 12>
The present invention was carried out except that the crosslinking charge transport layer coating solution of Example 1 did not contain a radical polymerizable compound having a charge transporting structure and the composition of the crosslinking charge transport layer coating solution was changed to the following. An electrophotographic photosensitive member was produced in the same manner as in Example 1.
10 parts of trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
10 parts of charge transport material with the following structure
Photopolymerization initiator 1 part (1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals))
Tetrahydrofuran 100 parts

<Comparative Example 13>
In Example 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the cross-linked charge transport layer was not provided on the charge transport layer and the thickness of the charge transport layer was about 28 μm.

<Comparative example 14>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 13, except that the charge transport material contained in the coating liquid for charge transport layer in Comparative Example 13 was replaced with the following compound.

<Comparative Example 15>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 13, except that the charge transport material contained in the coating liquid for charge transport layer in Comparative Example 13 was replaced with the following compound.

<Comparative Example 16>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 13, except that the charge transport material contained in the coating liquid for charge transport layer in Comparative Example 13 was replaced with the following compound.

<Comparative Example 17>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport material contained in the coating solution for charge transport layer of Example 1 was replaced with the following compound.

<Comparative Example 18>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport material contained in the coating solution for charge transport layer of Example 1 was replaced with the following compound.

<Comparative Example 19>
In Example 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that a crosslinked charge transport layer was not provided on the charge transport layer and a filler-dispersed protective layer having the following composition was formed on the charge transport layer. .
Alumina (average primary particle size: 0.3 μm, manufactured by Sumitomo Chemical Co., Ltd.) 3 parts Polycarbonate (Z Polyca, manufactured by Teijin Chemicals) 5.5 parts Tetrahydrofuran 220 parts Cyclohexanone 80 parts The following charge transport materials 4 parts

<Comparative Example 20>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 19, except that the charge transport material contained in the filler-dispersed protective layer coating solution of Comparative Example 19 was replaced with the following compound.

<Comparative Example 21>
In Comparative Example 6, an electrophotographic photosensitive member was produced in the same manner as in Comparative Example 6 except that a crosslinked charge transport layer was not provided on the charge transport layer and a filler-dispersed protective layer having the following composition was formed on the charge transport layer. .
Alumina (average primary particle size: 0.3 μm, manufactured by Sumitomo Chemical Co., Ltd.) 3 parts Polycarbonate (Z Polyca, manufactured by Teijin Chemicals) 5.5 parts Tetrahydrofuran 220 parts Cyclohexanone 80 parts The following charge transport materials 4 parts

<Comparative Example 22>
In Example 19, an electrophotographic photosensitive member was produced in the same manner as in Example 19 except that a crosslinked charge transport layer was not provided on the charge transport layer and a filler-dispersed protective layer having the following composition was formed on the charge transport layer. .
Alumina (average primary particle size: 0.3 μm, manufactured by Sumitomo Chemical Co., Ltd.) 3 parts Polycarbonate (Z Polyca, manufactured by Teijin Chemicals) 5.5 parts Tetrahydrofuran 220 parts Cyclohexanone 80 parts The following charge transport materials 4 parts

<Comparative Example 23>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge generation material of the charge generation layer coating solution of Example 1 was replaced with the X-type metal-free phthalocyanine of Synthesis Example (4).
<Comparative Example 24>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 13, except that the charge transport layer coating solution of Comparative Example 13 was changed to the following composition.
[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
10 parts low molecular charge transport material of the formula
Compound of the following structure Sanol LS2626 Sankyo 0.5 parts
Tetrahydrofuran 82 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

<Evaluation 1>
<Real machine test>
In the actual paper running, the electrophotographic photosensitive member is mounted on an electrophotographic process cartridge, and Ricoh's imgio
Using a Neo751 modified machine (photosensitive linear velocity (process linear velocity): 350 mm / sec), 300,000 actual paper feeding tests (A4, MyPaper made by NBS Ricoh, charging potential at start -800 V) were carried out, and wear Quantity measurement, bright part potential measurement, image density evaluation, negative ghost and background stain evaluation were performed. The results are shown in the following table.
Table 4 shows the measurement results of the characteristics of the photoconductor, such as measurement of wear amount and bright part potential.
(Abrasion amount measurement)
After the running of 100,000 sheets and 300,000 sheets, the photoreceptor was taken out, and the amount of wear was measured from the difference in film thickness of the photoreceptor before and after the running test. For film thickness measurement, an eddy current film thickness meter Fischer scope MMS (manufactured by Fischer) was used.
(Light area potential measurement)
Disassemble the development unit, attach an electrometer probe connected to the surface electrometer to the development unit, set the photoconductor on it, adjust the grid potential so that the dark part potential is -800 (V), then black By outputting a solid image, the bright part potential before running was measured. Further, the bright part potential was measured in the same manner after 100,000 sheets of running and 300,000 sheets of running. Surface electrometer is TREK
MODEL 344 was used.

Next, the characteristics of the actual image were also evaluated using the following evaluation items.
(Image density evaluation)
A halftone image with an image density of 50% was output before running and after running 100,000 sheets and 300,000 sheets, and the density change was confirmed before and after running.
(Negative ghost evaluation)
The negative ghost evaluation chart shown in FIG. 5 was output before running and after 100,000 running and 300,000 running, and the degree of negative ghost (FIG. 6) appearing in the halftone portion was evaluated.
(Earth dirt evaluation)
A white solid image (without light writing) was output before running and after 100,000 running and 300,000 running, and the soil was confirmed by visual observation.
<Environmental test>
The evaluation was performed in the same manner as described above except that evaluation was performed at 10 ° C. and humidity of 15% RH using a Ricoh-made Imagio Neo751 modified machine.
<Oxidizing gas exposure test 1>
Separately, the photoconductors shown in the examples and comparative examples were prepared, and gas exposure was performed by leaving them in a chamber adjusted to an atmosphere of NO gas concentration of 40 ppm and NO ₂ gas concentration of 10 ppm for 48 hours. After gas exposure, Ricoh imagio
Images were output using a Neo751 remodeling machine, and changes in image flow before and after gas exposure were confirmed.
Image density evaluation, negative ghost evaluation, background stain evaluation, and image flow evaluation were based on the following criteria.
(Double-circle): The level by which image quality hardly falls.
○: Image quality is slightly degraded, but there is no problem with visual observation. Δ: Level where degradation of image quality can be seen with visual observation. X: Level with serious problem in image quality. The test results are shown in the following table.

<Evaluation 2>
<Real machine test>
The electrophotographic photosensitive members described in Examples 1, 24 to 47 and 49 to 51 were prepared, and a running test of 1 million sheets was performed, wear amount measurement, bright part potential measurement, image density evaluation, negative ghost and background contamination evaluation. Was carried out as described above.
<Oxidizing gas exposure test 2>
The photoreceptors shown in Examples 1, 24 to 47 and 49 to 51 were separately prepared, and a 5 cm square tape was applied to the photoreceptor surface to mask the photoreceptor. NO gas concentration 40 ppm, was carried out Gas Exposure by 96 hours standing in the chamber was adjusted to an atmosphere of NO ₂ gas concentration 10 ppm. After gas exposure, Ricoh imagio
An image was output using a Neo751 remodeling machine, and the difference in image density between the gas exposure part and the masking part (unexposed part) was evaluated. Note that the masked part is considered not exposed to gas.
The image density difference was based on the following criteria.
5: Level at which the density difference between the exposed area and the mask area cannot be confirmed with the naked eye.
4: The density difference between the exposed part and the mask part can be confirmed slightly. 3: The density difference between the exposed part and the mask part can be confirmed, but there is no problem in the visual observation. Level 2: The density difference between the exposed part and the mask part is clear. Level 1 that can be confirmed: Level at which the difference in density between the exposed area and the mask area is very large. The test results are shown in the following table.

From the above results, it has a cross-linkable charge transport layer which satisfies the above-mentioned relational expressions (1) and (2) and is composed of a radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a charge transport structure. The electrophotographic photosensitive member has little increase in bright part potential after running test, no image flow due to negative ghosting or NOx exposure is observed, it has excellent wear resistance, and the occurrence of scumming is suppressed, resulting in long-term repeated It has become possible to stably obtain high-quality images even after use. In particular, the radical polymerizable monomer having no charge transporting structure has a functional group number of 3 or more and a molecular weight / functional group number of 250 or less and a radical polymerizable compound having a monofunctional charge transporting structure is cross-linked. Abrasion is improved, and the life of the photoreceptor can be further increased.
From the above results, it was confirmed that when the charge transport material of the charge transport layer is a distyryl compound, particularly a distyrylbenzene derivative, it has a great effect on reducing the bright part potential and also has a large effect on reducing the negative ghost. When the layer containing the distyrylbenzene derivative is formed on the outermost surface of the photoreceptor, the image flow is remarkably generated by exposure to NOx, but the crosslinked charge transport layer of the present invention is formed thereon. As a result, it is confirmed that the image flow is suppressed, the negative ghost is suppressed by reducing the bright portion potential increase, the background stain is also suppressed by improving the wear resistance, and a synergistic effect is obtained for stabilizing the image quality. It was done. On the other hand, when a filler-dispersed protective layer was provided, it was confirmed that image flow due to NOx exposure could not be suppressed, and that high image quality could be realized by laminating the cross-linked charge transport layer of the present invention.
In addition, from the above results, when the film thickness of the charge transport layer is thinner than twice the film thickness of the cross-linked charge transport layer, it is confirmed that the bright portion potential tends to increase, and the charge transport layer and the cross-linked charge transport layer film It was confirmed that thickness is also an important factor for high image quality.

Further, from the above results, when at least one of R ₃ , R ₈ , R ₁₉ and R ₂₄ of the distyrylbenzene derivative represented by the general formula (3) is a methyl group, it is effective for reducing the light portion potential. It was confirmed.
Further, from the above results, the compound represented by the general formula (4), the compound represented by the general formula (5-1), the compound represented by the general formula (5-2), the general formula It was confirmed that inclusion of the compound represented by (6) was effective in suppressing potential fluctuation after the running test and also improved the image stability after exposure to NOx.
Further, from the above results, it was confirmed that when the charge transport layer contains an antioxidant, it is effective in suppressing potential fluctuation after the running test and the image stability after exposure to NOx is also improved.
Furthermore, the compound represented by the general formula (4), the compound represented by the general formula (5-1), the compound represented by the general formula (5-2), and the compound represented by the general formula (6). It was confirmed that when any of these and an antioxidant was combined and contained in the charge transport layer, both the potential fluctuation suppressing effect after the running test and the image stability after exposure to NOx were significantly improved. Further, even when these compounds were added, the increase in the bright part potential was small.
From the above results, it was confirmed that the wear resistance was greatly improved when a filler was contained in the cross-linked charge transport layer.
Furthermore, the compound represented by the general formula (4), the compound represented by the general formula (5-1), the compound represented by the general formula (5-2), and the compound represented by the general formula (6). If any of these and an antioxidant is combined in the charge transport layer and a filler is added to the cross-linked charge transport layer, the potential fluctuation suppression effect after the running test is large, and the image stability after exposure to NOx is greatly improved. It was confirmed that the wear resistance and the wear resistance were greatly improved.

It is sectional drawing which shows the structural example of the electrophotographic photoreceptor in this invention. 1 is a schematic diagram illustrating an example of an image forming apparatus according to the present invention. It is a figure which shows an example of the process cartridge in this invention. It is an X-ray diffraction spectrum diagram of the charge generation material used in the examples, the vertical axis represents the counts per second (cps: counts per second), and the horizontal axis represents the angle (2θ). It is a schematic diagram of the chart for negative ghost evaluation used for image evaluation of the negative ghost of an Example. It is a schematic diagram of a negative ghost image obtained by printing a negative ghost evaluation chart.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Static elimination lamp 3 Charger charger 4 Eraser 5 Image exposure part 6 Developing unit 7 Charger before transfer 8 Registration roller 9 Transfer body 10 Transfer charger 11 Separation charger 12 Separation claw 13 Charger before cleaning 14 Fur brush 15 Cleaning blade 31 Conductivity Support 32 Charge generation layer 33 Charge transport layer 35 Crosslinkable charge transport layer 101 Photoconductor 102 Charging means 103 Exposure means 104 Development means 105 Transfer body 106 Transfer means 107 Cleaning means

Claims (19)

In an electrophotographic photosensitive member in which at least a charge generation layer, a charge transport layer, and a cross-linked charge transport layer are sequentially laminated on a conductive support,
In the charge generation layer, at least a metal phthalocyanine pigment as a charge generation material,
The charge transport layer contains at least a charge transport material having a triarylamine structure,
The crosslinked charge transport layer is formed by curing a radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a charge transport structure,
When the ionization potential of the charge generation layer is Ip (G), the ionization potential of the charge transport layer is Ip (T), and the ionization potential of the cross-linked charge transport layer is Ip (O),
The relationship of the following formula (1) and the following formula (2) is established: −0.16 ≦ Ip (T) −Ip (G) ≦ 0.07 (1)
0.07 <Ip (O) −Ip (G) ≦ 0.33 (2)
An electrophotographic photosensitive member characterized by the above. The functional group of the radical polymerizable monomer having no charge transporting structure and / or the functional group of the radical polymerizable compound having the charge transporting structure is an acryloyloxy group and / or a methacryloyloxy group. The electrophotographic photosensitive member according to claim 1. The number of functional groups of the radically polymerizable monomer having no charge transporting structure is 3 or more, and the ratio of molecular weight to the number of functional groups (molecular weight / functional group number) is 250 or less. The electrophotographic photosensitive member described. The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the charge transporting structure of the radical polymerizable compound having the charge transporting structure is a triarylamine structure. The radical polymerizable compound having the charge transporting structure,
The electrophotographic photosensitive member according to any one of claims 1 to 4, wherein the electrophotographic photosensitive member is at least one compound represented by the following general formula (1) or (2).
(In the formula, R ₄₀ represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a cyano group, a nitro group, A group, an alkoxy group, —COOR ₄₁ (R ₄₁ represents a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or an aryl group which may have a substituent. ), A carbonyl halide group or CONR ₄₂ R ₄₃ (R ₄₂ and R ₄₃ have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Represents an aryl group which may be the same or different from each other. Ar ₂ and Ar ₃ represent a substituted or unsubstituted arylene group and may be the same or different. A r ₄ and Ar _{5 each} represents a substituted or unsubstituted aryl group, which may be the same or different, and X is a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, substituted or unsubstituted Represents an unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group, Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group, or an alkyleneoxycarbonyl group, and m and n are 0 to 0. Represents an integer of 3.) The electrophotographic photoreceptor according to claim 1, wherein the charge transport material having a triarylamine structure contained in the charge transport layer is a distyryl compound. The electrophotographic photoreceptor according to claim 6, wherein the distyryl compound having a triarylamine structure is a distyrylbenzene derivative represented by the general formula (3) having the following structure.

[In the above formula, R _{1 to} R ₃₀ are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkyl group having 1 to 4 carbon atoms. It represents an aryl group substituted with an alkoxy group, and may be the same or different. ] The electrophotographic photosensitive member according to claim 7, wherein at least one of R ₃ , R ₈ , R ₁₉ and R ₂₄ of the distyrylbenzene derivative represented by the general formula (3) is a methyl group. The electrophotographic photosensitive member according to claim 1, wherein the crosslinkable charge transport layer contains a filler. The electrophotographic photosensitive member according to claim 1, wherein the charge transport layer contains an antioxidant. The electrophotographic photoreceptor according to claim 1, wherein the charge transport layer contains a charge transport material having a triarylamine structure and a compound represented by the following general formula (4).
(In the formula, R ₉₂ and R ₉₃ represent an aromatic ring group-substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, which may be the same or different. R ₉₂ and R ₉₃ are bonded to each other to form a nitrogen atom. And j and k each represent an integer of 0 to 3. However, j and k are not simultaneously 0. R ₉₄ and R ₉₅ are hydrogen atoms, substituted or unsubstituted. Represents an alkyl group having 1 to 11 carbon atoms and a substituted or unsubstituted aromatic ring group, which may be the same or different, and Ar ₅₁ and Ar ₅₂ each represent a substituted or unsubstituted aromatic ring group and are the same But it may be different.) The charge transport layer contains a charge transport material having a triarylamine structure, the distyryl compound, and a compound represented by the following general formula (5-1). Electrophotographic photoreceptor.
(In the formula, R ₉₆ and R ₉₇ represent a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted alkyl group, and may be the same or different. R ₉₆ and R ₉₇ are bonded to each other. And a heterocyclic group containing a nitrogen atom may be formed, Ar ₅₃ and Ar ₅₄ each represent a substituted or unsubstituted aromatic ring group, and p and q each represents an integer of 0 to 3, provided that p and q Are not simultaneously 0. r represents an integer of 1 to 3.) The electrophotographic photosensitive member according to any one of claims 1 to 10, wherein the charge transport layer contains a charge transport material having a triarylamine structure and a compound represented by the following general formula (5-2). body.
(Wherein R ₉₈ and R ₉₉ represent a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted alkyl group, and may be the same or different. R ₉₈ and R ₉₉ are bonded to each other. And a heterocyclic group containing a nitrogen atom, Ar ₅₅ and Ar ₅₆ each represents a substituted or unsubstituted aromatic ring group, and s and t each represents an integer of 0 to 3, provided that s and t Are not simultaneously 0. u represents an integer of 1 to 3.) The electrophotographic photoreceptor according to claim 1, wherein the charge transport layer contains a charge transport material having a triarylamine structure and a compound represented by the following general formula (6).
(Wherein R ₁₀₁ and R ₁₀₂ represent a substituted or unsubstituted alkyl group or a substituted or unsubstituted aromatic ring group, and may be the same or different. However, any one of R ₁₀₁ and R ₁₀₂ may be used. Is a substituted or unsubstituted aromatic ring group, and R ₁₀₁ and R ₁₀₂ may be bonded to each other to form a substituted or unsubstituted heterocyclic group containing a nitrogen atom, and Ar ₅₇ is a substituted or unsubstituted group. Represents an aromatic ring group of The electrophotographic photosensitive member according to any one of claims 1 to 14, wherein a film thickness T1 of the charge transport layer and a film thickness T2 of the cross-linked charge transport layer satisfy a relationship of the following formula (3). .
T1> T2 × 2 Formula (3) The image forming apparatus comprising at least a charging unit, an exposure unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of claims 1 to 15. An image forming apparatus characterized by that. The electrophotographic photosensitive member according to any one of claims 1 to 15, wherein a plurality of image forming elements including at least a charging unit, an exposing unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member are arranged. An image forming apparatus characterized by that. A cartridge in which an electrophotographic photosensitive member and at least one means selected from charging means, exposure means, development means, transfer means, and cleaning means are mounted, and the cartridge is detachable from the apparatus main body. The image forming apparatus according to claim 16, wherein the image forming apparatus is an image forming apparatus. In a cartridge in which an electrophotographic photosensitive member and at least one means selected from charging means, exposure means, development means, transfer means, and cleaning means are integrated,
16. The process cartridge for an image forming apparatus, wherein the electrophotographic photoreceptor is the electrophotographic photoreceptor according to any one of claims 1 to 15.