JP2011123089A - Electrophotographic photoreceptor, image forming apparatus, and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor in which dispersibility of a filler is enhanced and curing inhibition of a protective layer is reduced, and which moderately maintains the elution amount of a charge transporting substance to the protective layer. <P>SOLUTION: In the electrophotographic photoreceptor, a support is provided, and at least a charge generation layer, a charge transporting layer containing a charge transporting substance and a binder resin, and a protective layer containing a filler, a polycarboxylic compound, and a curable resin including a polymerizable compound having a charge transporting structure and a polymerizable compound not having the charge transporting structure are laminated on the support in this order. The contents of tetrahydrofuran and cyclopentanone are 50-10,000 ppm and 1-100 ppm, respectively, to the amount of solid content in all layers laminated on the support. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member, an image forming apparatus that uses the electrophotographic photosensitive member to form an image by an electrophotographic method, and a process cartridge. The image forming apparatus and the process cartridge of the present invention are widely applied to a copying machine, a facsimile, a laser printer, a direct digital plate making machine, and the like.

As electrophotographic photoreceptors, organic photoreceptors mainly using organic materials are widely used because of cost, productivity, freedom of material selection, influence on the global environment, and the like. The organic photoreceptor is composed of a photosensitive layer mainly containing a photosensitive material, a single layer type having a charge generation function and a charge transport function in one layer, a charge generation layer having a charge generation function, and a charge transport. It is roughly classified into a stacked type in which the function is separated into a charge transport layer having a function.
The mechanism of electrostatic latent image formation in a functionally separated layered photoreceptor is that when a uniformly charged photoreceptor is irradiated with light, the light passes through the charge transport layer and is absorbed by the charge generation material in the charge generation layer. Then, electric charges (charge pairs) are generated. One of them is injected into the charge transport layer at the interface between the charge generation layer and the charge transport layer, further moves in the charge transport layer by an electric field, reaches the surface of the photoreceptor, and neutralizes the surface charge given by charging. As a result, an electrostatic latent image is formed. These organic photoreceptors having a laminated structure are advantageous in terms of stability and durability of electrostatic characteristics, and are currently mainstream in electrophotographic photoreceptors.

  Improvement of not only the electrophotographic photosensitive member but also the developing material or the image forming apparatus main body is progressing, and the full color and high speed of the image forming apparatus using the organic photosensitive member are rapidly progressing. Along with this, printing applications have been diversified, and in recent years, electrophotographic image forming apparatuses have been deployed in the light printing field. In the light printing field, image defects do not occur even when the same image or document is repeatedly printed, and the image quality needs to be maintained stably. In order to realize this, the electrophotographic photosensitive member has excellent mechanical durability without being worn or scratched even after repeated printing over a long period of time. It is important to achieve excellent electrostatic durability without causing a decrease in charge, a rise in residual potential, and a decrease in sensitivity, and simultaneously realizing these.

Conventional techniques for improving the abrasion resistance (mechanical durability) of a photoreceptor include (1) a surface layer using a curable binder (see, for example, Patent Document 1), and (2) polymer charge transport. Examples include those using substances (for example, see Patent Document 2), (3) those in which a filler is dispersed in a surface layer (for example, see Patent Document 3), and the like.
Among these technologies, those that use the curable binder of (1), although light and abrasion resistance and scratch resistance are improved to some extent by curing, light printing that is used under severer conditions than the general office field Assuming that it is used in the field, the effect is not sufficient. When curing the surface layer, substances that are not involved in the reaction contained in the surface layer cause curing inhibition, and if unreacted monomers remain in the layer, the residual potential increases, the charge decreases, the gas resistance decreases, etc. There is a fear. Further, when the curing reaction is promoted in order to increase the degree of curing, the residual potential rises remarkably and it is difficult to achieve both mechanical durability and electrostatic durability.
The material using the polymer type charge transport material (2) can improve the abrasion resistance to some extent, but does not have sufficient mechanical durability for use in the light printing field. In addition, polymer charge transport materials are difficult to polymerize and purify, and it is difficult to obtain high-purity materials, and the electrostatic durability is not sufficient. Furthermore, production problems such as high viscosity of the coating solution may occur.
In the case where the filler (3) is dispersed, the wear resistance is improved, but the effect is not sufficient in the light printing field. Although the mechanical durability is increased by containing the filler, the detached filler may damage the surface of the photoreceptor, and when it progresses, there is a risk of promoting filming or adhesion of foreign matter. Further, the residual potential increases due to the charge trap sites existing on the filler surface, and the image density tends to decrease.
As described above, although the conventional technology can improve the abrasion resistance of the photosensitive member, it is light in mechanical and electrostatic durability, such as electrostatic deterioration and occurrence of image defects. Not enough for use in the printing field.

On the other hand, a method of combining these techniques, using a cured resin for the surface layer, and further containing a filler is disclosed.
For example, a method for forming a protective layer using a coating liquid in which conductive metal oxide fine particles are dispersed in a specific curable acrylic monomer is disclosed (for example, see Patent Document 4). Further, a method is disclosed in which fine particles and a binder resin crosslinked with a block type isocyanate are contained in the surface layer (see, for example, Patent Document 5). Also disclosed is a method of dispersing filler fine particles in a crosslinked resin layer obtained by curing a tri- or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a charge transport structure (for example, patents). Reference 6). Further, a method is disclosed in which the surface layer contains a thermosetting binder resin, a charge transport material having a crosslinkable functional group, and conductive fine particles (see, for example, Patent Document 7).

Thus, the inclusion of the filler in the cured resin is a very effective method for improving the wear resistance. When conductive fine particles are used for the filler, it is almost always added for the purpose of controlling the resistance of the surface layer, but a great effect can be obtained also in improving the wear resistance.
However, when a substance that does not participate in the curing reaction is mixed with the cured resin, there are not a few cases in which these effects are not obtained due to inhibition of curing. Therefore, the method of incorporating the filler in the cured resin can be expected to have a great effect, but it involves a great difficulty in producing it.
For example, the dispersibility of a filler is mentioned as a subject. As a method for enhancing the dispersibility of the filler, a method using an unsaturated polycarboxylic acid type wet dispersant having an acid value of 30 to 400 (mgKOH / g) is disclosed (for example, see Patent Document 8). The method is a very effective method.
However, in these known patents, a thermoplastic resin is used as the binder resin, which is technically different from an electrophotographic photoreceptor using a cured resin. That is, in the case of using a cured resin, it is necessary to cure in a state in which a filler is contained, and the filler itself may induce curing inhibition. When curing inhibition occurs, the above-described effects cannot be obtained when a cured resin is used, and this is not a problem that can be solved only by these known techniques.

In addition, a method is disclosed in which after the step of dispersing the filler in a solvent without adding a binder resin, a coating liquid for forming the surface layer is prepared by mixing with a binder resin solution (for example, a patent) Reference 9).
This method is a very effective method for improving the dispersibility and dispersion stability of the filler, but this method alone cannot provide an effect on the present invention using the cured resin.
As described above, the protective layer in which the filler is dispersed in the cured resin is a very effective method for enhancing the durability of the photoreceptor, but there are many problems to be overcome in order to obtain these effects. . Therefore, a method for solving these problems has been eagerly desired for realizing high durability of the photoreceptor.

As described above, a photoconductor provided with a protective layer in which a filler is dispersed in a cured resin has significantly increased wear resistance and scratch resistance, and the surface state of the photoconductor does not change even after repeated printing over a long period of time. This is one of the very effective technologies that can sufficiently cope with applications in the light printing field.
However, when a protective layer made of a filler and a cured resin is formed on the charge transport layer, the presence of the filler may inhibit the curing reaction of the cured resin. If the dispersibility of the filler is high, this is not a big problem, but if the dispersibility is poor and the filler is remarkably agglomerated, the inhibition of curing becomes significant and the ability to hold the filler decreases. In addition, when the filler aggregates and becomes in a state of poor dispersibility, the filler with a small coverage with the resin increases, and as a result, the filler is easily detached. As a result, the wear resistance of the photoreceptor is significantly reduced. Furthermore, when the curing is not sufficient due to the inhibition of curing, the scratch resistance of the surface of the photoreceptor is also lowered. In this case, if the filler is easily detached due to a decrease in the filler holding power, a further scratch is formed by the detached filler, so that deterioration of wear resistance and scratch resistance is accelerated.

In addition, the aggregation of the filler greatly affects the film quality of the protective layer, and very large irregularities are formed on the surface, or a protrusion-like coating film defect occurs. These cause problems such as spotted image defects and poor toner cleaning. Furthermore, if the dispersibility of the filler is poor, the filler in the coating solution immediately settles, so that the filler content changes over time, and the uniformity of the filler contained in the protective layer decreases. As a result, uneven wear and partial electrostatic deterioration occur, and spotted image defects and image density unevenness occur in the obtained image.
Therefore, in order to form a protective layer in which a filler is dispersed in a cured resin, it is very important to improve the dispersibility of the filler.

Moreover, hardening inhibition does not only occur due to filler aggregation. When forming the protective layer on the photosensitive layer, if the charge transport material contained in the photosensitive layer is dissolved by the solvent contained in the protective layer forming coating solution, the charge transport material is eluted in the protective layer and eluted. Curing inhibition may be caused by the charge transport material. In particular, when the amount of the charge transport material eluted into the protective layer is very large, the inhibition of curing becomes remarkable, and the wear resistance and scratch resistance are remarkably lowered. Furthermore, when a charge transport material having a low ionization potential is contained in the photosensitive layer, if a large amount of the charge transport material is eluted in the protective layer, the resolution is lowered and image blurring occurs in an oxidizing gas atmosphere, resulting in a significant increase in image quality. May fall.
In addition, if the amount of the charge transport material elution into the protective layer becomes very large, not only does it itself cause inhibition of curing, but also when the protective layer is cured by UV irradiation, these charge transport materials will absorb UV light. In order to absorb, the influence by preventing the hardening reaction inside a protective layer is also seen. In this case, in order to further accelerate the curing reaction, if the amount of UV irradiation is increased or the polymerization initiator is increased more than necessary, in most cases a significant increase in residual potential or a decrease in sensitivity is observed, or the protective layer There are many side effects such as generation of wrinkles and cracks, deterioration of adhesion with the photosensitive layer, and film peeling.
Therefore, excessive elution of the charge transport material into the protective layer must be avoided.

Further, the influence of the solvent contained in the protective layer cannot be ignored as a causative substance that causes curing inhibition. In general, since curing is performed after the protective layer is applied, depending on the type and amount of the remaining solvent, the mechanical durability is greatly lowered due to inhibition of curing. In addition, these residual solvents may promote an increase in residual potential and fluctuations in electrostatic characteristics during storage, and also reduce electrostatic durability. Therefore, it is preferable that these residual solvents are as small as possible.
As a prior art relating to the residual solvent, a photoconductor in which 0.05 to 10.0% by mass of cyclopentanone is contained in the photoconductive layer is disclosed (for example, see Patent Document 10). Further, there is disclosed a photoreceptor using a specific titanyl phthalocyanine and defining a residual concentration of tetrahydrofuran and cyclobutanone in the charge transport layer (see, for example, Patent Document 11).
However, the effects of improving both mechanical durability and electrostatic durability are difficult to obtain by these methods.

  As described above, in order to form a protective layer in which a filler is dispersed in a cured resin, the dispersibility of the filler is increased, and the charge transport material in the charge transport layer eluted from the filler or the protective layer, a residual solvent, etc. It is important to reduce cure inhibition. Since the dispersibility of the filler is greatly affected by the wettability of the solvent (dispersion medium) used at the time of dispersion, the selection of the dispersion medium is very important. The elution of the charge transport material into the protective layer is greatly affected by the solubility of the solvent contained in the protective layer coating solution in the charge transport material. When a lot of highly soluble solvents are included, the amount of charge transport material elution into the protective layer increases, and when many solvents with low solubility are contained, elution of the charge transport material is reduced, The protective layer may be peeled off or the charge transport material may be deposited. Moreover, since the solubility with respect to a solvent changes also with the kind of charge transport material, it is one factor influencing hardening inhibition. In addition, when the residual solvent of the protective layer is included, it can be understood that these problems are related to the solvent, but the dispersibility of the filler is improved, and the elution of the charge transport material and the influence of the residual solvent on the curing inhibition are small. It is difficult to specify a solvent, and there has been a strong demand for an electrophotographic photosensitive member and an image forming apparatus that are compatible with mechanical and electrostatic durability and can stably output a high-quality image even when used repeatedly.

  An object of the present invention is to solve the conventional problems and achieve the following objects. That is, in a protective layer containing at least a filler, a polycarboxylic acid compound, a polymerizable compound having a charge transporting structure and a polymerizable resin not having a charge transporting structure, dispersion of the filler contained in the protective layer It is possible to maintain the moderate amount of elution of the charge transport material into the protective layer, thereby preventing uneven wear and surface scratches due to the detachment of the filler. However, there is little fluctuation in the residual potential and the exposed portion potential, and as a result, it has excellent mechanical and electrostatic durability, and even if repeated printing is performed over a long period of time, it does not generate image defects and can stably output high-quality images. An object is to provide an electrophotographic photosensitive member, an image forming apparatus using the same, and a process cartridge.

In order to solve the above problems, the present inventors have intensively studied and obtained the following knowledge.
That is, the protective layer contains at least a filler, a polycarboxylic acid compound, a polymerizable compound having a charge transporting structure and a polymerizable compound not having a charge transporting structure, and further formed on a conductive support. In addition, the content of tetrahydrofuran with respect to the solid content of all layers is set to 50 ppm to 10,000 ppm, and the content of cyclopentanone is set to 1 ppm to 100 ppm. It has been found that the amount of charge transport material in the photosensitive layer can be reduced and the amount of elution into the protective layer can be appropriately maintained.
This finding mainly prevents dispersion of fillers in order to prevent inhibition of curing of the protective layer, increase mechanical durability, and at the same time suppress increase in residual potential and exposed area potential, and also improve electrostatic durability. The amount of solvent and the amount of elution of the charge transport material into the protective layer and the amount of the solvent are paid attention.

The reason why the dispersibility of the filler is remarkably increased is considered that the effect of the addition of the polycarboxylic acid compound and cyclopentanone is large. One reason why the dispersibility of the filler is deteriorated is that the affinity between the filler and the solvent or organic material is poor. One reason for the improvement in dispersibility is that the surface of the filler is easily wetted by the solvent by keeping other hydrophobic groups compatible with the solvent and the organic material.
However, even if a polycarboxylic acid compound is added, these effects are greatly affected by the solvent species. In the present invention, it has been found that filler dispersibility can be remarkably improved by adding a polycarboxylic acid compound during dispersion and further using cyclopentanone as a solvent. Therefore, one of the effects of the present invention is obtained by a combination of a polycarboxylic acid compound and cyclopentanone.

  Moreover, cyclopentanone is effective for improving filler dispersibility, and also effective for stabilizing the high filler dispersibility obtained by adding a polycarboxylic acid compound for a long period of time. As a result, the effect of suppressing the sedimentation of the filler in the protective layer coating liquid can be obtained, and even if sedimented, the filler dispersion state can be recovered by lightly stirring and the liquid life can be greatly improved. It was. Due to these effects, the filler is uniformly contained in the protective layer without agglomeration, and influences such as uneven wear and hardening inhibition by the filler can be reduced, and mechanical durability can be maintained. Further, even if the coating solution is stored at rest, the dispersibility is restored by stirring again during use. Therefore, a stable photoreceptor can always be produced using the same coating solution.

  Moreover, cyclopentanone can obtain not only the dispersibility of the filler but also the effect of improving the adhesion between the charge transport layer and the protective layer due to the inclusion thereof. When a cured resin is used for the protective layer, there is a large difference in hardness between the charge transport layer and the protective layer, and the protective layer may peel off depending on the hardness or the film thickness of the protective layer. When the protective layer is peeled off, the mechanical durability cannot be maintained, and even if the peeling is very slight, the charge cannot reach the surface in that region, so that an image defect occurs. Therefore, a decrease in adhesiveness in the protective layer is a very important issue in increasing the durability of the photoreceptor.

Furthermore, cyclopentanone is effective in suppressing an increase in residual potential and exposed portion potential in repeated use, particularly in coexistence with tetrahydrofuran. This effect may be observed not only in the protective layer but also in other layers than the protective layer, such as a charge transport layer and a charge generation layer. Cyclopentanone is effective for improving the adhesiveness of the protective layer and reducing the potential of the exposed portion, and appropriately maintains the elution of the charge transport material to the protective layer that occurs when the protective layer is applied on the charge transport layer. It is thought that one of the reasons is that it is possible. The term “moderate” as used herein refers to an amount of elution that increases the charge injection property at the interface between the protective layer and the charge transport layer, improves the adhesion of the protective layer, and affects the inhibition of curing and image blurring. The level is not reached.
That is, in the formation of the protective layer, if the elution amount of the charge transport material from the charge transport layer increases, the influence of curing inhibition increases, so it is necessary to suppress it. On the other hand, if there is no elution of the charge transport material into the protective layer, it may cause an increase in the exposed area potential, a decrease in sensitivity, a decrease in the adhesion of the protective layer, and the like. Therefore, in order to achieve both mechanical durability and electrostatic durability, it is necessary to maintain a moderate amount of elution of the charge transport material into the protective layer, and this state contains tetrahydrofuran and cyclopentanone. I found out that it depends on the amount.

Thus, the protective layer contains at least a filler, a polycarboxylic acid compound, a polymerizable compound having a charge transporting structure and a polymerizable compound having no charge transporting structure, and further on the conductive support. By setting the content of tetrahydrofuran to 50 ppm to 10,000 ppm and the content of cyclopentanone to 1 ppm to 100 ppm with respect to the solid content of the entire layer formed, the mechanical durability and electrostatic property of the photoreceptor are increased. Durability can be increased at the same time.
Specifically, by forming a protective layer that is excellent in dispersibility and dispersion stability of the filler and has little influence on curing inhibition or film peeling, the surface wear resistance and scratch resistance are increased, and the filler is removed. Separation is also suppressed, and mechanical high durability of the photoreceptor is realized. In addition, due to the filler contained in a good dispersion state, a very fine uneven shape is formed on the surface of the photoreceptor, and as a result, the occurrence of image defects due to filming or poor cleaning is suppressed, and the effect is It remains stable even after repeated use. In addition, since the elution of the charge transport material contained in the charge transport layer to the protective layer is appropriately maintained, an increase in the residual potential in repeated use is suppressed, the stability of the exposed portion potential is increased, and the electrostatic potential is increased. High durability is achieved at the same time.
As described above, according to the configuration of the electrophotographic photosensitive member investigated by the present inventors, the mechanical and electrostatic durability is excellent, and the occurrence of image defects is suppressed even when used repeatedly over a long period of time. The inventor has obtained the knowledge that an extremely excellent effect that an image can be output stably can be exhibited.

The present invention is based on the above knowledge, and means for solving the above problems are as follows. That is,
<1> Polymer having a support, a charge generation layer, a charge transport layer containing a charge transport material and a binder resin, a filler, a polycarboxylic acid compound, and a charge transport structure on the support. A protective layer containing a curable resin containing a compound and a polymerizable compound having no charge transporting structure is laminated in this order, and the content with respect to the solid content of all layers laminated on the support Is an electrophotographic photoreceptor characterized in that it is 50 ppm to 10,000 ppm for tetrahydrofuran and 1 ppm to 100 ppm for cyclopentanone.
<2> The electrophotographic photosensitive member according to <1>, wherein the content of tetrahydrofuran with respect to the solid content of all layers laminated on the support is 200 ppm to 3,000 ppm.
<3> The electrophotographic photosensitive member according to any one of <1> to <2>, wherein the content of cyclopentanone with respect to the solid content of all layers laminated on the support is 2 ppm or more and 30 ppm or less. .
<4> The electrophotographic photoreceptor according to any one of <1> to <3>, wherein tetrahydrofuran is contained in the charge transport layer and the protective layer, and cyclopentanone is contained in the protective layer.
<5> The electrophotographic photosensitive member according to any one of <1> to <4>, wherein the charge transport material has a molecular weight of 600 or more and 900 or less.
<6> The electrophotographic photosensitive member according to any one of <1> to <5>, wherein the charge transport material is a distyryl compound represented by the following general formula (1).
However, in said formula (1), R < ₁ > -R < ₄ > represents either a hydrogen atom, a C1-C4 alkyl group, a C1-C4 alkoxy group, and a phenyl group, respectively, respectively. But it can be different. The phenyl group may be unsubstituted or substituted with any substituent of an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms.
A represents any of an arylene group which may have a substituent and a group represented by the following general formula (1a).
However, in said formula (1a), R < ₅ >, R < ₆ > and R < ₇ > represent either a hydrogen atom, a C1-C4 alkyl group, a C1-C4 alkoxy group, and a phenyl group, respectively. . The phenyl group may be unsubstituted or substituted with any substituent of an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms.
B and B ′ each represent an aryl group which may have a substituent and a group represented by the following general formula (1b). B and B ′ may be the same or different.
However, in the formula (1b), Ar ₁ represents an arylene group that may have a substituent or an alkyl group and an alkoxy group having 1 to 4 carbon atoms, Alternatively, Ar ₂ and Ar ₃ , Each represents an aryl group optionally having any one of an alkyl group having 1 to 4 carbon atoms and an alkoxy group as a substituent.
<7> The electrophotographic photosensitive member according to <6>, wherein the charge transport material is a distyryl compound represented by the following general formula (2).
However, in said formula (2), R < ₈ > -R < ₃₃ > is a phenyl group which may have a hydrogen atom, a C1-C4 alkyl group, a C1-C4 alkoxy group, and a substituent, respectively. Each of which may be the same or different.
<8> The electrophotographic photosensitive member according to <6>, wherein the charge transport material is a distyryl compound represented by the following general formula (3).
However, in said formula (3), R < ₃₄ > -R < ₅₇ > is a phenyl group which may have a hydrogen atom, a C1-C4 alkyl group, a C1-C4 alkoxy group, and a substituent, respectively. Each of which may be the same or different.
<9> The electrophotographic photosensitive member according to any one of <1> to <8>, wherein the charge transporting structure of the polymerizable compound having a charge transporting structure is a triarylamine structure.
<10> The above <1, wherein any of the polymerizable compound having a charge transporting structure and the polymerizable compound not having a charge transporting structure has at least one of an acryloyloxy group and a methacryloyloxy group as a polymerizable functional group. > To <9>.
<11> The polymerizable compound having no charge transporting structure has three or more polymerizable functional groups, and the polymerizable compound having a charge transporting structure has one polymerizable functional group. 10>. The electrophotographic photosensitive member according to any one of 10).
<12> The electrophotographic photosensitive member according to any one of <1> to <11>, wherein the filler is metal oxide particles.
<13> The electrophotographic photosensitive member according to <12>, wherein the metal oxide particles are α-alumina particles.
<14> The electrophotographic photosensitive member according to any one of <1> to <13>, wherein an average primary particle size of the filler is 0.05 μm or more and less than 0.7 μm.
<15> The electrophotographic photosensitive member according to any one of <1> to <14>, wherein the protective layer has a thickness of 1 μm to 5 μm.
<16> The electrophotographic photosensitive member according to any one of <1> to <15>, wherein the ten-point average roughness Rz of the protective layer surface is 0.3 μm or more and 1.0 μm or less.
<17> The electrophotographic photosensitive member according to any one of <1> to <16>, wherein an average interval Sm of unevenness existing on the surface of the protective layer is 0.3 mm or more and 1.0 mm or less.
<18> At least the electrophotographic photosensitive member according to any one of <1> to <17>, a charging unit that charges the electrophotographic photosensitive member, and an electrostatic latent image formed on the electrophotographic photosensitive member An image forming apparatus comprising: an exposing unit that performs development; a developing unit that develops the electrostatic latent image with toner; and a transfer unit that transfers the developed toner image to a recording medium.
<19> The image forming apparatus according to <18>, wherein the image forming apparatus is a tandem type in which a plurality of image forming elements including at least an electrophotographic photosensitive member, a charging unit, an exposure unit, a developing unit, and a transfer unit are arranged.
<20> The image forming apparatus according to any one of <18> to <19>, wherein the image forming apparatus further includes a lubricating substance applying unit that applies a lubricating substance to the surface of the electrophotographic photosensitive member.
<21> The electrophotographic photosensitive member according to any one of <1> to <17>, and at least one unit selected from a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit; Is a process cartridge that can be attached to and detached from the main body of the image forming apparatus.

  According to the present invention, the conventional problems can be solved, the object can be achieved, and at least a filler, a polycarboxylic acid compound, a polymerizable compound having a charge transporting structure and a polymerization not having a charge transporting structure In the protective layer containing a cured resin composed of a functional compound, the dispersibility of the filler contained in the protective layer is increased, and further, the inhibition of curing of the protective layer is small, and the elution amount of the charge transport material to the protective layer can be maintained moderately This prevents uneven wear and surface scratches due to filler detachment, and there are few fluctuations in residual potential and exposed portion potential even after repeated use, resulting in excellent mechanical and electrostatic durability. An electrophotographic photosensitive member capable of stably outputting high-quality images without causing image defects even after repeated printing over a long period of time, an image forming apparatus using the same, and a process cartridge It is possible to provide a cartridge.

It is the schematic which shows an example of the laminated constitution of the electrophotographic photoreceptor in this invention. It is the schematic which shows another example of the layer structure of the electrophotographic photoreceptor in this invention. It is the schematic for demonstrating the image formation process in this invention. It is explanatory drawing of the charging means of a proximity arrangement type roller system. It is another schematic diagram for explaining an image forming process in the present invention. FIG. 6 is still another schematic diagram for explaining an image forming process in the present invention. It is the schematic for demonstrating the process cartridge of 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 the schematic of the accelerated abrasion test apparatus used in the Example. It is an example of the measurement result by SAICAS used in the Example. It is another example of the measurement result by SAICAS used in the Example.

(Electrophotographic photoreceptor)
The electrophotographic photoreceptor of the present invention comprises a support, and at least a charge generation layer, a charge transport layer, and a protective layer laminated in this order on the support, and is laminated on the support. The content with respect to the solid content of all the layers is 50 ppm to 10,000 ppm for tetrahydrofuran and 1 ppm to 100 ppm for cyclopentanone.

  The layer structure of the electrophotographic photoreceptor is not particularly limited as long as at least the charge generation layer, the charge transport layer, and the protective layer are laminated in this order on the support. Depending on the purpose, it can be selected as appropriate, and if necessary, an undercoat layer and other layers are further laminated. There is no restriction | limiting in particular as said undercoat layer, For example, the layer distribute | arranged between the said charge generation layer and the said support body is mentioned.

<Support>
The support is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a conductive support exhibiting a conductivity of 10 ¹⁰ Ω · cm or less, such as aluminum, nickel, and chromium. , Metal such as nichrome, copper, gold, silver, platinum, metal oxide such as tin oxide, indium oxide, etc. coated on film or cylindrical plastic or paper by vapor deposition or sputtering; aluminum, aluminum alloy, A plate made of nickel, stainless steel, or the like, and a tube subjected to surface treatment such as cutting, superfinishing, polishing, or the like after forming them into a raw pipe by a method such as extrusion or drawing can be used. Further, for example, endless nickel belts and endless stainless steel belts disclosed in JP-A-52-36016 can be used as the conductive support.

Furthermore, what formed the electroconductive layer (it formed using coating etc.) by disperse | distributing electroconductive powder to binder resin on the said electroconductive support body can also be used as an electroconductive support body.
There is no restriction | limiting in particular as said electroconductive powder, Carbon black, acetylene black; Metal powder, such as aluminum, nickel, iron, nichrome, copper, zinc, silver, metal oxide powder, such as electroconductive tin oxide, ITO Etc. As the binder resin used simultaneously, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, Polyvinyl acetate, polyvinylidene chloride, polyarylate, 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, thermosetting resins, and photocurable resins.
There is no restriction | limiting in particular as said electroconductive layer, It can provide by disperse | distributing electroconductive powder and binder resin to solvents, such as tetrahydrofuran, a dichloromethane, methyl ethyl ketone, toluene, and apply | coating.
Furthermore, using a heat shrinkable tube containing conductive powder in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, polytetrafluoroethylene fluororesin, etc. Those provided with a conductive layer can also be used as a conductive support.

Among the conductive supports according to the above examples, a cylindrical support made of aluminum that can easily perform the anodic oxide coating treatment is preferable. The aluminum may include either a pure aluminum system or an aluminum alloy. Specifically, JIS 1,000, 3,000, and 6,000 aluminum or aluminum alloys are most suitable.
The anodic oxide coating is not particularly limited, and examples thereof include those obtained by anodizing various metals and various alloys in an electrolyte solution. Among them, at least one of aluminum and an aluminum alloy is anodized in an electrolyte solution. The applied coating called anodized is effective because it has a small residual potential increase and is effective in preventing scumming that occurs when reversal development is used.

There is no restriction | limiting in particular as said anodizing process, It can carry out in acidic baths, such as chromic acid, a sulfuric acid, oxalic acid, phosphoric acid, a boric acid, sulfamic acid. Of these, treatment with a sulfuric acid bath is most suitable. For example, sulfuric acid concentration: 10 to 20%, bath temperature: 5 to 25 ° C., current density: 1 to 4 A / dm ² , electrolytic voltage: 5 to 30 V, treatment time: treatment in the range of about 5 to 60 minutes However, the present invention is not limited to this.
Since the anodic oxide film thus produced is porous and has high insulation, the surface is very unstable. For this reason, there is a change with time after fabrication, and the physical property value of the anodic oxide coating is likely to change. In order to avoid this, it is preferable to further seal the anodized film.
The sealing treatment is not particularly limited, and includes a method of immersing the anodized film in an aqueous solution containing nickel fluoride or nickel acetate, a method of immersing the anodized film in boiling water, a method of treating with pressurized water vapor, and the like. Can be mentioned. Among these, the method of immersing in the aqueous solution containing nickel acetate is the most preferable.
Subsequent to the sealing treatment, the anodic oxide coating is preferably washed. The main purpose of this is to remove excessive deposits such as metal salts deposited by the sealing treatment.
If excessive deposits remain on the surface of the support (anodized coating), not only will it adversely affect the quality of the coating film formed on the substrate, but generally low resistance components will remain. It can also cause soiling. Cleaning may be performed with pure water only once, but usually, multistage cleaning is performed. At this time, it is preferable that the final cleaning liquid is as clean as possible (deionized). Moreover, it is preferable to perform physical rubbing cleaning with a contact member in one of the multi-stage cleaning processes.
The thickness of the anodized film formed as described above is not particularly limited, but is preferably 5 μm to 15 μm. If it is thinner than this, the effect of the barrier property as an anodic oxide film is not sufficient, and if it is thicker than this, the time constant as an electrode becomes too large, and the generation of residual potential and the response of the photoreceptor are reduced. There is a case.

<Charge generation layer>
The charge generation layer is a layer mainly composed of a charge generation material.
The charge generation material is not particularly limited, and a known charge generation material can be used. For example, a monoazo pigment, a disazo pigment, an asymmetric disazo pigment, a trisazo pigment, an azo pigment having a carbazole skeleton (for example, special No. 53-95033), azo pigments having a distyrylbenzene skeleton (for example, see JP-A-53-133445), azo pigments having a triphenylamine skeleton (for example, JP-A-53-132347). Gazette), azo pigments having a diphenylamine skeleton, azo pigments having a dibenzothiophene skeleton (see, for example, JP-A No. 54-21728), azo pigments having a fluorenone skeleton (see, for example, JP-A No. 54-22834) ), An azo pigment having an oxadiazol skeleton (for example, JP-A-54-127) No. 2), azo pigments having a bis-stilbene skeleton (for example, see JP-A-54-17733), azo pigments having a distyryloxadiazol skeleton (for example, see JP-A-54-2129) ), Azo pigments such as azo pigments having a distyrylcarbazole skeleton (see, for example, JP-A-54-14967), azulenium salt pigments, squalic acid methine pigments, perylene pigments, anthraquinone pigments, and many Ring quinone pigments, quinoneimine pigments, diphenylmethane and triphenylmethane pigments, benzoquinone and naphthoquinone pigments, cyanine and azomethine pigments, indigoid pigments, bisbenzimidazole pigments, and represented by the following general formula (4) Phthalocyanine skeletons such as metal phthalocyanine and metal-free phthalocyanine Pigment (phthalocyanine pigment), and the like have.

However, in said Formula (4), M (central metal) represents the element of a metal and a non-metal (hydrogen). M (central metal) mentioned here is H, 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 oxide, chloride It consists of two or more elements such as fluoride, fluoride, hydroxide and bromide. The central metal is not limited to these elements.

  The pigment having the phthalocyanine skeleton only needs to have at least the basic skeleton of the formula (4), has a multimeric structure such as a dimer or trimer, and has a higher order polymer structure. It doesn't matter. In addition, the basic skeleton may have various substituents. Of these various phthalocyanines, titanyl phthalocyanine having TiO as a central metal, metal-free phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, and the like are particularly preferable in terms of photoreceptor characteristics. These 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. Even in the phthalocyanine having the same central metal, various characteristics change as the crystal system changes. It has been reported that the characteristics of photoreceptors using phthalocyanine pigments having these various crystal systems also change accordingly (Journal of Electrophotographic Society, Vol. 29, No. 4, 1990). Therefore, the selection of the phthalocyanine crystal system is very important in terms of the photoreceptor characteristics.

  Among these phthalocyanine pigments, a titanyl phthalocyanine crystal having a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (1.542 °) of CuKα is particularly It has a high sensitivity and can be used particularly effectively in the present invention because it enables high-speed image formation. 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 the diffraction peak at the lowest angle side is 7.3. 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 large charge generation efficiency. They can also be used very effectively as the charge generating material of the present invention because they have good electrostatic properties and are less likely to cause scumming. These charge generation materials can be used alone or as a mixture of two or more.

The charge generation material is not particularly limited, but it is effective because the effect may be enhanced by making the particle size finer. In particular, in the phthalocyanine pigment, the average particle size is preferably 0.25 μm or less, and more preferably 0.2 μm or less. Among the azo pigments, azo pigments represented by the following general formula (5) are effectively used. In particular, an asymmetric disazo pigment in which Cp ₁ and Cp ₂ of the azo pigment are different from each other has a large carrier generation efficiency and is effective for increasing the speed, and is preferably used as the charge generation material.

However, in the above formula _{(5), Cp 1, Cp} 2 represents a coupler residue. R ₂₀₁ and R ₂₀₂ each represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or a cyano group, and may be the same or different. Cp ₁ and Cp ₂ are represented by the following general formula (5a), and an asymmetric disazo pigment is obtained by giving different structures to each other.

However, in the formula (5a), R ₂₀₃ represents a hydrogen atom, an alkyl group such as a methyl group or an ethyl group, or an aryl group such as a phenyl group. R ₂₀₄ , R ₂₀₅ , R ₂₀₆ , R ₂₀₇ and R ₂₀₈ are each a hydrogen atom, a nitro group, a cyano group, a halogen atom such as fluorine, chlorine, bromine or iodine, or a halogenated alkyl group such as a trifluoromethyl group, Represents an alkyl group such as a methyl group or an ethyl group, an alkoxy group such as a methoxy group or an ethoxy group, a dialkylamino group, or a hydroxyl group, and Z represents a substituted or unsubstituted carbocyclic aromatic group aromatic carbocycle Or a substituted or unsubstituted heteroaromatic group represents an atomic group necessary for constituting an aromatic heterocycle. These charge generation materials may be used alone or in combination of two or more.

  The binder resin used as necessary for the charge generation layer is not particularly limited and may be appropriately selected depending on the purpose. For example, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, Acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl acetal, polyvinyl ketone, polystyrene, poly-N-vinyl carbazole, polyacrylamide, 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. Among these, polyvinyl butyral is preferably used. These binder resins can be used alone or as a mixture of two or more.

  The solvent used for forming the charge generation layer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, isopropanol, acetone, methyl ethyl ketone, cyclohexanone, cyclopentanone, tetrahydrofuran, dioxane, ethyl Commonly used organic solvents such as cellsolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin, etc. are used, but among them, ketone solvents, ester solvents, ether solvents are used. It is preferable to do. These may be used alone or in combination of two or more. In the present invention, methyl ethyl ketone, cyclopentanone, or a mixed solvent thereof is particularly preferable. By containing cyclopentanone, the dispersibility of the charge generating material is improved, and effects such as high sensitivity, reduction of residual potential, and stabilization of electrostatic characteristics by repeated use may be obtained.

The coating solution used for coating the charge generation layer is not particularly limited, but known as a ball mill, an attritor, a sand mill, a bead mill, an ultrasonic wave and the like together with the binder resin as necessary. It can be prepared by dispersing in a solvent using a dispersion method. 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 the charge generation material, the solvent and the binder resin, and includes a sensitizer, a dispersant, a surfactant, silicone oil and the like. An agent may be included. In some cases, a charge transport material described later can be added to the charge generation layer.
There is no restriction | limiting in particular as the addition amount of the said binder resin, Usually, it is 0 mass part-500 mass parts with respect to 100 mass parts of said charge generation materials, and 10 mass parts-300 mass parts are preferable.

The charge generation layer is formed by coating on the conductive support or the undercoat layer using the coating liquid and drying.
There is no restriction | limiting in particular as the method of the said coating, Well-known methods, such as a dip coating method, a spray coat, a bead coat, a nozzle coat, a spinner coat, a ring coat, can be used.
The thickness of the charge generation layer is usually about 0.01 μm to 5 μm, preferably 0.1 μm to 2 μm.
Moreover, as drying after coating, heat drying using oven etc. is mentioned.
Although there is no restriction | limiting in particular as a drying temperature of the said charge generation layer, 50 to 160 degreeC is preferable and 80 to 140 degreeC is more preferable.

<Charge transport layer>
The charge transport layer is mainly composed of a charge transport material and a binder resin. Examples of the electric transport material include a hole transport material and an electron transport material.
The electron transport material is not particularly limited, and examples thereof include 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4,5,7-tetranitro. Xanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-trinitrodibenzothiophene-5,5 -Substances generally showing electron acceptability such as dioxide, naphthalenetetracarboxylic acid diimide, aromatic rings having a cyano group or a nitro group.
The hole transport material is not particularly limited, and poly (N-vinylcarbazole) and derivatives thereof, poly (γ-carbazolylethyl glutamate) and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, Polyvinylphenanthrene, polysilane, oxazole derivative, oxadiazole derivative, imidazole derivative, monoarylamine derivative, diarylamine derivative, triarylamine derivative, stilbene derivative, α-phenylstilbene derivative, aminobiphenyl derivative, benzidine derivative, diarylmethane derivative, Triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazoline derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc. , A distyrylbenzene derivative, an enamine derivative, or a polymer charge transport material. These may be used alone or in combination of two or more.
The charge transport material has a function of transporting charges, but when the protective layer is formed on the charge transport layer, the charge transport material contained in the charge transport layer is eluted into the protective layer. Depending on the amount of elution, there is a risk of causing inhibition of curing in the protective layer. Therefore, the molecular weight of the charge transport material is preferably 600 or more and 900 or less, and more preferably 650 or more and 800 or less.
The charge transporting material having a molecular weight of 600 or more has a large molecular size and a low solubility in a solvent. As a result, even if a protective layer is formed on the charge transporting layer, the charge transporting material is excessive in the protective layer. Since elution tends to be suppressed, it can be preferably used. The solubility of the charge transport material is not necessarily determined only by the molecular weight, and varies depending on the molecular structure of the charge transport material, but it is considered that the larger the molecular size, the more difficult it is to escape from the binder resin. Is preferably a charge transport material having a molecular weight of 600 or more in order to maintain the elution of the compound in the protective layer moderately. However, it is important to completely dissolve in the solvent contained in the charge transport layer coating solution.
On the other hand, when the molecular weight exceeds 900, the solvent solubility tends to decrease, and even if dissolved, the amount of elution into the protective layer is extremely small, and the charge injection property at the protective layer / photosensitive layer interface decreases. Or the protective layer may be easily peeled off, or crystals may be deposited in some cases.
Thus, even by selecting the charge transport material, the elution of the charge transport material into the protective layer can be appropriately maintained, preventing excessive curing inhibition, and charging the protective layer. The effect of improving the injection property and further improving the adhesiveness of the protective layer can be obtained at the same time.

  Since the amount of elution into the protective layer is also affected by the structure of the charge transport material, there are particularly preferred materials among the charge transport materials. In the present invention, among the charge transport materials, compounds containing a distyryl structure are effective, and among them, a distyryl compound represented by the following general formula (1) is very effective in the present invention.

However, in said formula (1), R < ₁ > -R < ₄ > represents either a hydrogen atom, a C1-C4 alkyl group, a C1-C4 alkoxy group, and a phenyl group, respectively, respectively. But it can be different. The phenyl group may be unsubstituted or substituted with any substituent of an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms.

  A represents an arylene group which may have a substituent and a group represented by the following general formula (1a).

However, in said formula (1a), R < ₅ >, R < ₆ > and R < ₇ > respectively represent either a hydrogen atom, a C1-C4 alkyl group, a C1-C4 alkoxy group, and a phenyl group, The phenyl group may be unsubstituted or substituted with any substituent of an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms.

  B and B ′ each represent an arylene group which may have a substituent and a group represented by the following general formula (1b). B and B ′ may be the same or different.

However, in said formula (1b), Ar < ₁ > represents the arylene group which may have either a C1-C4 alkyl group and an alkoxy group as a substituent, and Ar < ₂ > and Ar < ₃ > are And each represents an arylene group optionally having any one of an alkyl group having 1 to 4 carbon atoms and an alkoxy group as a substituent.

  Among these compounds, the distyryl compound represented by the following general formula (2) is particularly effective, effective and useful in the present invention.

However, in said formula (2), R < ₈ > -R < ₃₃ > is a phenyl group which may have a hydrogen atom, a C1-C4 alkyl group, a C1-C4 alkoxy group, and a substituent, respectively. Each of which may be the same or different.

  In addition, a charge transport material represented by the following general formula (3) is also effective in the present invention.

However, in said formula (3), R < ₃₄ > -R < ₅₇ > is a phenyl group which may have a hydrogen atom, a C1-C4 alkyl group, a C1-C4 alkoxy group, and a substituent, respectively. Each of which may be the same or different.

  These charge transport materials are preferably used because the π-conjugated system has a feature that spreads throughout the molecule, so that the mobility and charge transport properties are high and the amount of elution to the protective layer does not become excessive. Can do.

  Specific examples of the compound used as the charge transport material are shown below. However, these are merely examples, and the present invention is not limited to these specific examples.

  The binder resin used for forming the charge transport layer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene- Maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal , Polyvinyltoluene, poly (N-vinylcarbazole), acrylic resins, silicone resins, epoxy resins, melamine resins, urethane resins, phenol resins, alkyd resins, and other thermoplastic or thermosetting resins. Among these, polycarbonate and polyarylate are preferably used.

  There is no restriction | limiting in particular as content of the said charge transport material, Usually, it is 20 mass parts-300 mass parts with respect to 100 mass parts of binder resin, and 40 mass parts-150 mass parts is preferable. It is also possible to use two or more kinds of charge transport materials or a mixture of two or more binder resins.

  The solvent used as the coating solution for the charge transport layer is not particularly limited, and tetrahydrofuran, dioxane, dioxolane, toluene, cyclohexanone, cyclopentanone, methyl ethyl ketone, xylene, acetone, diethyl ether, methyl ethyl ketone and the like are used. Among these, tetrahydrofuran, cyclopentanone, or a mixed solvent thereof is preferably used as a solvent that is effectively used. These may be used alone or in combination of two or more.

  Moreover, you may add additives, such as a single or 2 or more types of plasticizers, a leveling agent, a lubricant, and antioxidant, as a coating liquid of the said charge transport layer as needed. In particular, the charge transport materials represented by the above formulas (1), (2), and (3) may cause cracks in the film due to adhesion of sebum and stress. In this case, the addition of a plasticizer or an antioxidant can prevent cracks, which is effective for exerting the effects of the present invention.

Although there is no restriction | limiting in particular as said plasticizer, Plasticizers, such as a dibutyl phthalate and a dioctyl phthalate, are preferable.
Although there is no restriction | limiting in particular as addition amount of the said plasticizer, 0 mass%-30 mass% are preferable with respect to the said binder resin, and 1 mass%-10 mass% are more preferable.
The leveling agent is not particularly limited, and for example, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers having a perfluoroalkyl group in the side chain, oligomers, and the like are preferable.
Although there is no restriction | limiting in particular as addition amount of the said leveling agent, 0 mass%-1 mass% are preferable with respect to the said binder resin, and 0.01 mass%-0.5 mass% are more preferable. Thereby, the coating-film defect of a charge transport layer can be prevented, and a smooth film | membrane can be formed.

  The antioxidant is not particularly limited, and examples thereof include conventionally known materials such as phenolic compounds, paraphenylenediamines, hydroquinones, organic sulfur compounds, organic phosphorus compounds, hindered amines, It is effective for stabilizing the electrostatic characteristics against repeated use. The charge transport material having a particularly low ionization potential tends to be less stable in an oxidizing gas atmosphere, but it can be used well even in an oxidizing gas atmosphere by adding these antioxidants. In addition, an effect of suppressing image blur can be obtained, which is effective for improving image quality. Among these antioxidants, antioxidants represented by the following structural formula are particularly effectively used.

The addition amount of the antioxidant is preferably 0% by mass to 20% by mass and more preferably 0.1% by mass to 10% by mass with respect to the charge transport material. When the added amount exceeds 20% by mass, a sudden increase in residual potential may be observed. On the other hand, if the amount added is too small, there may be a case where a decrease in charge is observed in an atmosphere of high concentration oxidizing gas.
The antioxidant is preferably a compound having an alkylamino group. The compound having an alkylamino group has an effect of suppressing image flow, charge reduction, etc. generated in a high-concentration atmosphere of ozone or NOx, and particularly when a charge transport material having a small ionization potential is used. It is particularly effective. By adding the compound having an alkylamino group, resolution reduction and image blurring are suppressed even in an oxidizing gas atmosphere, and electrostatic deterioration such as charge reduction is also suppressed, resulting in high image quality. Can do. In addition, since these compounds have a charge transport structure themselves, they have little effect on the residual potential and can be added in a relatively large amount.
Although there is no restriction | limiting in particular as a compound which has the said alkylamino group, The compound shown by following General formula (10), (11) is preferable.

However, in said Formula (10), Ar < ₄ > represents a substituted or unsubstituted arylene group. Ar ₅ and Ar ₆ each represent a substituted or unsubstituted aryl group, a substituted or unsubstituted alkyl group, and a substituted or unsubstituted aralkyl group, and may be the same or different. R ₅₈ and R ₅₉ each represent a substituted or unsubstituted alkyl group and a substituted or unsubstituted aralkyl group, and may be the same or different. Ar ₅ and R ₅₈ , Ar ₆ and R ₅₉ may be bonded to each other to form a substituted or unsubstituted heterocyclic group containing a nitrogen atom. )
However, in said Formula (11), Ar < ₇ > represents a substituted or unsubstituted arylene group. R _{60 to} R ₆₃ each represent a substituted or unsubstituted alkyl group and a substituted or unsubstituted aralkyl group, and may be the same or different. n represents an integer of 1 or 2.

The method for coating the charge transport layer is not particularly limited, and for example, known methods such as dip coating, spray coating, bead coating, nozzle coating, spinner coating, ring coating, etc. can be used. A coating method is more preferable.
After coating, it is manufactured by heating and drying in an oven or the like. The drying temperature of the charge transport layer varies depending on the type of the solvent contained in the coating liquid for the charge transport layer, but is preferably 80 ° C to 150 ° C, more preferably 100 ° C to 140 ° C. Moreover, as drying time, 10 minutes-60 minutes are preferable, and 15 minutes-30 minutes are more preferable.
The drying condition of the charge transport layer is an important factor that determines the amount of tetrahydrofuran and cyclopentanone contained in the photoconductor. The higher the drying temperature, the longer the drying time, the content of these solvents. The content of these solvents increases at lower drying temperatures and shorter drying times.
There is no restriction | limiting in particular as thickness of the said charge transport layer, Usually, 10 micrometers-50 micrometers, 15 micrometers-35 micrometers are preferable. Further, the electrophotographic photoreceptor is more preferably 20 μm to 30 μm because the protective layer is formed on the surface.

<About protective layer>
The protective layer contains at least a filler, a polycarboxylic acid compound, a cured resin containing a polymerizable compound having a charge transporting structure and a polymerizable compound not having a charge transporting structure.

Examples of the filler material include organic fillers and inorganic fillers.
There is no restriction | limiting in particular as said organic filler material, Fluorine resin powder like polytetrafluoroethylene, silicone resin powder, a-carbon powder, etc. are mentioned.
The inorganic filler material is not particularly limited, and metal powder such as copper, tin, aluminum, and indium, silica, tin oxide, zinc oxide, titanium oxide, alumina, zirconia, indium oxide, antimony oxide, bismuth oxide, and oxide. Inorganic materials such as metal oxides such as tin oxide doped with calcium and antimony, indium oxide doped with tin, metal fluorides such as tin fluoride, calcium fluoride and aluminum fluoride, potassium titanate and boron nitride It is done.
Among these fillers, inorganic materials, particularly metal oxides are preferably used from the viewpoints of filler hardness and light scattering properties, from the viewpoint of wear resistance and high image quality. Furthermore, the use of the metal oxide is also advantageous for coating quality. The coating film quality greatly affects image quality and wear resistance, and is effective for high durability and high image quality.

Furthermore, a filler having high electrical insulation is preferred as a filler that is less likely to cause image blur. When the conductive filler is contained on the outermost surface of the photoreceptor, the lateral resistance is lowered due to a decrease in surface resistance, and image blurring is likely to occur. In particular, the specific resistance of the filler is preferably 10 ⁷ Ω · cm or more from the viewpoint of resolution.
There is no restriction | limiting in particular as such a filler, An alumina, a zirconia, a titanium oxide, a silica etc. are mentioned. Among them, α-alumina, which is a hexagonal close-packed structure with high light transmission, high thermal stability and excellent wear resistance, suppresses image blur and improves wear resistance, coating quality, and light transmission. It can be used particularly effectively from the standpoint of sex.
On the other hand, the conductive filler is not particularly limited, and examples thereof include tin oxide, acid value indium, acid value antimony, antimony-doped tin oxide, and tin-doped indium oxide. Image blurring tends to occur, which tends to be undesirable. However, even if the filler is the same material, the specific resistance of the filler may be different and is not completely classified by the filler material, but it is important to determine the specific resistance of the filler.
It is also possible to use a mixture of two or more of these fillers, whereby the surface resistance can be controlled. The specific resistance of the filler can be measured using, for example, a powder resistance measuring device. Specifically, the metal oxide powder is put in a cell and sandwiched between electrodes, the load is applied, the amount of the metal oxide powder is adjusted so that the thickness is about 2 mm, and then a voltage is applied between the electrodes. At that time, the specific resistance can be obtained by measuring the flowing current.

  Furthermore, these fillers can be surface treated with at least one kind of surface treating agent. An effect of improving the dispersibility of the filler may be obtained by the surface treatment on the filler.

The average primary particle size of the filler is not particularly limited and may be appropriately selected according to the purpose. From the viewpoint of light transmittance and wear resistance, 0.05 μm or more and 0.7 μm or less are preferable, More preferably, it is 0.1 μm or more and 0.5 μm or less.
If the average primary particle size of the filler is less than 0.05 μm, the filler is likely to agglomerate and decrease in wear resistance. If the average primary particle size exceeds 0.7 μm, the sedimentation of the filler is promoted or the image quality deteriorates. Or an abnormal image may occur.

Although there is no restriction | limiting in particular as addition amount of the said filler, 0.1 mass%-50 mass% are preferable with respect to the total solid contained in the layer in which the said filler contains, 3 mass%-30 mass% Is more preferable, and 5% by mass to 20% by mass is particularly preferable.
If the added amount of the filler is less than 0.1% by mass, the required wear resistance cannot be obtained, and if it exceeds 50% by mass, the residual potential increases, image blurring, resolution decreases, and the like. The effect of deterioration tends to increase.

  The polycarboxylic acid compound is a compound having a plurality of carboxyl groups in the structure, and this plays an important role in obtaining the effect of reducing the residual potential and improving the dispersibility of the filler. Since fillers, particularly hydrophilic metal oxides, have a low affinity with organic materials such as organic solvents and resins, dispersion does not proceed, and even if dispersion is performed, they immediately aggregate. In contrast, in the polycarboxylic acid compound, the carboxylic acid moiety in the structure has a high affinity with the filler, and the other polymer moiety has a high affinity with an organic material such as an organic solvent. The affinity between the filler and the organic material can be increased via the acid compound. Therefore, the filler is easily wetted by the solvent due to the dispersion, and as a result, the polycarboxylic acid compound spreads to every corner of the filler surface, and the polycarboxylic acid compound thus adsorbed on the filler becomes the filler. It is considered that the effect of suppressing reaggregation can be obtained while the dispersibility of the filler is increased due to a steric hindrance between them.

Moreover, the said polycarboxylic acid compound has an acid value by having a carboxyl group itself. The acid value is defined as the number of milligrams of potassium hydroxide necessary to neutralize the carboxyl group contained in 1 g of resin. The polycarboxylic acid compound having this acid value is adsorbed on a polar group that causes an increase in the residual potential on the filler surface and fills the charge trap sites, thereby obtaining not only an effect of increasing dispersibility but also an effect of reducing the residual potential. It will be possible.
Even with a carboxylic acid having one carboxyl group, the effect of the present invention is recognized, but a polycarboxylic acid compound having more carboxyl groups is extremely high in improving the dispersibility of the filler and reducing the residual potential. An effect can be obtained.
The acid value of the polycarboxylic acid compound is preferably 100 mgKOH / g to 400 mgKOH / g. If the acid value is less than 100 mgKOH / g, the effect of reducing the residual potential may not be sufficiently obtained. If the acid value exceeds 400 mgKOH / g, the resolution may be lowered and image blur may occur in an oxidizing gas atmosphere. There is.
However, whatever polycarboxylic acid compound is used, it is possible to suppress the influence by adjusting the addition amount, and the balance between the acid value of the polycarboxylic acid compound, the addition amount, and the addition amount of the filler. It is important to decide by

The addition amount of the dispersant used for forming the protective layer preferably satisfies the following relational expression, but is more preferably set to the minimum necessary amount.
1 <(addition amount of dispersing agent × acid value of dispersing agent) / (addition amount of filler) <40
If the value of (dispersing agent addition amount × dispersing agent acid value) / (filler addition amount) in the above relational expression exceeds 40, the resolution may be reduced and image blurring may occur, and the dispersibility may be reversed. May fall. On the other hand, if it is less than 1, the dispersibility is lowered, or the effect of reducing the residual potential cannot be obtained, and as a result, an abnormal image may be generated.
Among these polycarboxylic acid compounds, the polycarboxylic acid type wetting dispersant “BYK-P104” provided by BYK Chemie is a particularly suitable material for obtaining the effects of the present invention. These techniques are disclosed in Japanese Patent No. 3802787.

  Even if the polycarboxylic acid compound is added, the effect on dispersibility and residual potential may not be sufficiently obtained. It depends on the solvent used during dispersion, that is, the dispersion medium. By using cyclopentanone as this dispersion medium, the present invention not only maximizes the effect on dispersibility and residual potential, but also can suppress resin curing inhibition and film quality degradation. This is based on the finding that a synergistic effect of pentanone and a polycarboxylic acid compound can be obtained. In the present invention, the effect can be obtained by containing the cyclopentanone. However, particularly when the filler is dispersed, the polycarboxylic acid compound and the cyclopentanone coexist to obtain a very large effect. be able to.

As the binder resin (curable resin) contained in the protective layer, a resin obtained by curing at least a polymerizable compound having a charge transporting structure and a polymerizable compound not having a charge transporting structure is used.
Since the protective layer needs to increase the wear resistance and at the same time transport charges, it can be achieved by curing and using a polymerizable compound having no charge transport function and a polymerizable compound having a charge transport function. . The term “polymerization” as used herein refers to the former polymerization reaction form in which the polymer compound formation reaction is largely divided into chain polymerization and sequential polymerization, and the form mainly reacts via intermediates such as radicals or ions. This refers to unsaturated polymerization, ring-opening polymerization, isomerization polymerization, and the like. Moreover, a polymeric compound means the compound which has a functional group in which the said reaction form is possible. Curing is generally a monomer or oligomer having the above-mentioned functional group bonded between molecules by applying energy such as heat, light such as visible light or ultraviolet light, radiation such as electron beam or γ-ray (for example, (Covalent bond), a reaction that forms a three-dimensional network structure.

The curable resin is not particularly limited, and examples thereof include a thermosetting resin that is polymerized by heat, a photocurable resin that is polymerized by light such as ultraviolet rays or visible light, and an electron beam curable resin that is polymerized by an electron beam. If necessary, it is used in combination with a curing agent, 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. These functional groups are not particularly limited as long as they are functional groups that cause a polymerization reaction, and include known unsaturated polymerizable functional groups and ring-opening polymerizable functional groups. The unsaturated polymerizable functional group is a reaction in which an unsaturated group is polymerized by radicals or ions, for example, a functional group such as C═C, C≡C, C═O, C═N, and C≡N. Is mentioned. The ring-opening polymerizable functional group is a reaction in which an unstable cyclic structure having a strain such as a carbocyclic ring, an oxo ring, or a nitrogen heterocyclic ring repeats polymerization at the same time as the ring opening, thereby generating a chain polymer. Most of the ions act as active species.
Examples of these include groups having a carbon-carbon double bond such as acryloyl group, methacryloyl group and vinyl group, groups that cause ring-opening polymerization such as silanol group and cyclic ether group, or reaction of two or more kinds of molecules. Things.
Further, in the curing reaction, as the number of functional groups in one molecule of the reactive monomer, the larger the three-dimensional network structure is, the more effective the trifunctional or more functional groups are. 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.

The curable resin is not particularly limited as long as the polymerizable compound having no charge transport structure and the polymerizable compound having a charge transport structure are cured, and conventionally known materials can be used. A high effect can be obtained regardless of the material and means.
Examples of the curable resin include phenol resin, epoxy resin, melamine resin, alkyd resin, urethane resin, amino resin, polyimide resin, siloxane resin, acrylic resin, and the like, and particularly urethane resin, phenol resin, acrylic / methacrylic resin. Resin, siloxane, epoxy resin and the like are preferably used. Among these, acrylic / methacrylic resins have good electrostatic characteristics, can easily obtain the effects of the present invention, and can be used favorably. In addition, these curable resins are characterized in that a three-dimensional network structure is formed and insoluble in an organic solvent. Therefore, in the present invention, the state in which the curable resin is cured can be determined to be cured if, for example, the film does not dissolve even when an alcohol-based organic solvent is attached.

  When a polymerizable compound having no charge transporting structure and a polymerizable compound having a charge transporting structure are cured to form a three-dimensional network structure, a curing agent, a catalyst, a polymerization initiator, etc. It is possible to further increase the degree of curing by mixing in advance. As a result, the wear resistance of the protective 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 this reason, it is possible to obtain a high effect for enhancing the durability and image quality of the photoreceptor.

  The polymerizable compound having a charge transporting structure may be any compound that includes a structure exhibiting charge transporting properties and has a functional group for curing, and a conventionally known material can be used. Here, the charge transporting structure is a structure contained in the charge transporting substance, and thereby refers to a structure that expresses the charge transporting property. In addition, the charge transporting structure is roughly divided into a structure that mainly transports holes and a structure that transports electrons, and both are included in the present invention.

  The charge transporting structure, that is, the hole transporting structure or the electron transporting structure may be one or plural in the compound, and a plurality is more preferable because of excellent charge transportability. In addition, the polymerizable compound having the charge transporting structure may have a bipolar property including the hole transporting structure and the electron transporting structure in the molecule.

  Among the charge transport structures, examples of the hole transport structure include poly-N-vinyl carbazole, poly-γ-carbazolyl ethyl glutamate, pyrene-formaldehyde condensate, polyvinyl pyrene, polyvinyl phenanthrene, polysilane, oxazole. Oxadiazole, imidazole, monoarylamine, diarylamine, triarylamine, stilbene, α-phenylstilbene, benzidine, diarylmethane, triarylmethane, 9-styrylanthracene, pyrazoline, divinylbenzene, hydrazone, indene, butadiene, Examples of the structure generally show electron donating properties such as pyrene, bisstilbene, and enamine.

  Examples of the electron transporting structure include chloroanil, bromoanil, 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-trinitrodibenzothiophene-5,5-dioxide, condensed polycyclic quinone, diphenoquinone, benzoquinone, naphthalenetetracarboxylic acid diimide, aromatic ring having cyano group or nitro group, etc. It is done. Among these, the triarylamine structure is particularly effective because of its high charge transportability.

Next, an acrylic / methacrylic resin will be described in detail as an example.
The polymerizable compound having no charge transporting property is, for example, electron withdrawing having a hole transporting structure such as the above-mentioned triarylamine, hydrazone, pyrazoline, carbazole, such as condensed polycyclic quinone, diphenoquinone, cyano group and nitro group. It is a compound which does not have an electron transporting structure such as an aromatic ring and has a polymerizable functional group. The polymerizable functional group may be any group as long as it has a carbon-carbon double bond and is polymerizable. Examples of these 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 chemical formula (1).

However, in the chemical formula (1), X ₁ represents 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, — COO— group, —CONR ₂₂₈ group (R ₂₂₈ represents an alkyl group such as hydrogen, methyl group, and ethyl group, an aralkyl group such as benzyl group, naphthylmethyl group, and phenethyl group, and an aryl group such as phenyl group and naphthyl group. ) Or -S- group.

Specific examples of these substituents include a vinyl group, a styryl group, a 2-methyl-1,3-butadienyl group, a vinylcarbonyl group, an acryloyloxy group, an acryloylamide group, and a vinyl thioether group.
(2) 1,1-Substituted Ethylene Functional Group Examples of the 1,1-substituted ethylene functional group include functional groups represented by the following chemical formula (2).

However, in the chemical formula (2), Y ₄ is optionally substituted alkyl group, an optionally substituted aralkyl group, a phenyl group which may have a substituent, naphthyl Aryl groups such as groups, halogen atoms, cyano groups, nitro groups, alkoxy groups such as methoxy groups or ethoxy groups, —COOR ₂₂₉ groups {R ₂₂₉ is a hydrogen atom, an optionally substituted methyl group, ethyl An alkyl group such as a group, an aralkyl group such as an optionally substituted benzyl or phenethyl group, an aryl group such as an optionally substituted phenyl group or naphthyl group, or -CONR ₂₃₀ R ₂₃₁ ( R ₂₃₀ and R ₂₃₁ are each a hydrogen atom, which may have a substituent methyl group, an alkyl group, a benzyl group which may have a substituent such as an ethyl group, Fuchirumechiru group or an aralkyl group, or may have a substituent phenyl group, such as a phenethyl group, an aryl group such as a naphthyl group, may be the same or different from one another), also, X ₂ is Formula The same substituent as X _{1 in} (1), a single bond, and an alkylene group are represented. However, at least one of Y ₄ and X ₂ is an oxycarbonyl group, 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 ₁ , X ₂ , and Y ₄ include, for example, an alkyl group such as a halogen atom, a nitro group, a cyano group, a methyl group, and an ethyl group, a methoxy group, and an ethoxy group. And aryloxy groups such as a phenoxy group, aryl groups such as a phenyl group and a naphthyl group, and aralkyl groups such as a benzyl group and a phenethyl group. Among these polymerizable functional groups, acryloyloxy group and methacryloyloxy group are particularly useful as the polymerizable functional group.

The polymerizable compound not having the charge transporting structure is preferably polyfunctional and more preferably has three or more polymerizable functional groups. When a polymerizable compound (polymerizable monomer) having no tri- or higher functional charge transport structure is cured, a three-dimensional network structure is developed, and a high hardness and high elasticity layer having a very high crosslinking density is obtained. In addition, it is uniform and highly smooth, and high wear resistance 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 monofunctional or bifunctional polymerizable monomers or by mixing them.

Hereinafter, the polymerizable compound having no trifunctional or higher functional charge transport structure effective for improving the wear resistance will be described.
As a compound having three or more acryloyloxy groups corresponding to the polymerizable compound, for example, a compound having three or more hydroxyl groups in the molecule and acrylic acid (salt), acrylic acid halide, acrylic acid ester, It can be obtained by an ester reaction or a transesterification reaction. A compound having three or more methacryloyloxy groups can be obtained in the same manner. The polymerizable functional groups in the monomer having three or more polymerizable functional groups may be the same or different.

  Specific examples of the trifunctional or higher functional polymerizable compound having no charge transporting structure include the following. However, it is not limited to these compounds.

  That is, examples of the polymerizable compound include trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, trimethylolpropane alkylene-modified triacrylate, trimethylolpropane ethyleneoxy-modified (hereinafter EO-modified) triacrylate, trimethylol. Propanepropyleneoxy modified (hereinafter PO modified) triacrylate, trimethylolpropane caprolactone modified triacrylate, trimethylolpropane alkylene modified trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol triacrylate, glycerol epichlorohydrin Modified (hereinafter ECH modified) triacrylate, glycerol EO modified Reacrylate, glycerol PO-modified triacrylate, tris (acryloxyethyl) isocyanurate, dipentaerythritol hexaacrylate (DPHA), dipentaerythritol caprolactone-modified hexaacrylate, dipentaerythritol hydroxypentaacrylate, alkylated dipentaerythritol pentaacrylate, Alkylated dipentaerythritol tetraacrylate, alkylated dipentaerythritol triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, phosphoric acid EO-modified triacrylate, 2,2,5,5, -tetrahydroxymethyl Such as cyclopentanone tetraacrylate, which are used alone It may be a good combination of two or more can have.

  The polymerizable compound having no charge transporting structure has a molecular weight ratio (molecular weight / functional group number) of 250 or less to the number of functional groups in the compound in order to form a dense cross-linking in the protective layer. Is preferable. When this ratio is larger than 250, the protective layer is soft and wear resistance is somewhat lowered. Therefore, in the monomers exemplified above, monomers having a modifying group such as EO, PO, caprolactone, etc. have an extremely long modifying group. It may be difficult to use what it has alone.

  As content of the polymeric compound which does not have the said charge transportable structure, 20 mass%-80 mass% are preferable with respect to the said protective layer whole quantity, and 30 mass%-70 mass% are more preferable. When the content is less than 20% by mass, the protective layer has a small three-dimensional cross-linking density, and a dramatic improvement in wear resistance is not achieved as compared with the case where a conventional thermoplastic binder resin is used. When it exceeds mass%, the content of the polymerizable compound having the charge transporting structure is relatively decreased, and the residual potential may be remarkably increased. Depending on the process used, the required electrostatic properties and wear resistance differ, and the thickness of the protective layer varies accordingly. However, it cannot be generally stated, but considering the balance of both properties, it is 30% to 70% by mass. A range is most preferred.

Next, the polymerizable compound having the charge transporting structure will be described.
The polymerizable compound having a charge transporting structure is, for example, a hole transporting structure such as the aforementioned triarylamine, hydrazone, pyrazoline, carbazole, etc., for example, an electron withdrawing property having a condensed polycyclic quinone, diphenoquinone, a cyano group, or a nitro group. It is a compound having either or both of electron transport structures such as aromatic rings and having a polymerizable functional group.

Examples of the polymerizable functional group include those shown for the polymerizable compound having the charge transporting structure. Particularly, an acryloyloxy group and a methacryloyloxy group are useful, and the polymerizable compound having the charge transporting structure, And any one of the polymerizable compounds not having the charge transporting structure preferably has at least one of the acryloyloxy group and the methacryloyloxy group.
As the polymerizable compound having a charge transporting structure used in the protective layer, any number of functional groups can be used. From the viewpoint of stability of electrostatic properties and film quality, one polymerizable functional group is used. It is preferable to have. In the case of bifunctional or higher, a plurality of bonds are fixed in the cross-linked structure, and the cross-linking density is further increased. Become. In addition, the intermediate structure (cation radical) at the time of charge transport cannot be stably maintained, and there is a risk that a decrease in sensitivity due to charge trapping and an increase in residual potential are likely to occur.

  As the charge transporting structure of the polymerizable compound having the 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. For example, when a compound represented by the structure of the following general formula (12) or (13) is used, electrostatic characteristics such as sensitivity and residual potential are improved and can be used favorably.

However, in said formula (12) and (13), _R232 has a hydrogen atom, a halogen atom, the alkyl group which may have a substituent, the aralkyl group which may have a substituent, and a substituent. Aryl group, cyano group, nitro group, alkoxy group, and —COOR ₂₄₁ (R ₂₄₁ may be a hydrogen atom, an alkyl group that may have a substituent, an aralkyl group that may have a substituent, or a substituent. Aryl group which may have a group), halogenated carbonyl group or CONR ₂₄₂ R ₂₄₃ (R ₂₄₂ and R ₂₄₃ represent a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, and a substituent, respectively. Any one of an aralkyl group which may have and an aryl group which may have a substituent, which may be the same or different, and represents Ar ₁₄₁ or Ar _{14. 2} represents a substituted or unsubstituted arylene group, which may be the same or different. Ar ₁₄₃ and Ar ₁₄₄ each represent a substituted or unsubstituted aryl group, and may be the same or different. X represents any of 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, and a vinylene group. Z represents any of a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, and an alkyleneoxycarbonyl divalent group. m and n each represents an integer of 0 to 3.

Specific examples of those represented by the general formulas (12) and (13) are shown below.
In the general formulas (12) and (13), among the substituents of _R232 , examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the aryl group include a phenyl group and a naphthyl group. Examples of the aralkyl group include a benzyl group, a phenethyl group, and a naphthylmethyl group, and examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group. Group, alkyl group such as methyl group and ethyl group, alkoxy group such as methoxy group and ethoxy group, aryloxy group such as phenoxy group, aryl group such as phenyl group and naphthyl group, aralkyl group such as benzyl group and phenethyl group, etc. May be substituted. Among the substituents of R _232, it is particularly preferred, a hydrogen atom, a methyl group. Substituted or unsubstituted Ar ₁₄₃ and Ar ₁₄₄ 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 are preferable.
Examples of the non-condensed 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 rings such as 9,9-diphenylfluorene Examples thereof include monovalent groups of aggregated hydrocarbon compounds. Examples of the heterocyclic group include monovalent groups such as carbazole, dibenzofuran, dibenzothiophene, oxadiazole, and thiadiazole.

Moreover, the aryl group represented by Ar ₁₄₃ and Ar ₁₄₄ may have a substituent as shown below, for example.
(1) Halogen atom, cyano group, nitro group and the like.
(2) Alkyl groups, preferably C1-C12, especially C1-C8, more preferably C1-C4 linear or branched alkyl groups, and these alkyl groups further include a fluorine atom, a hydroxyl group, a cyano group, It may have a phenyl group substituted with a C1-C4 alkoxy group, a phenyl group or a halogen atom, a C1-C4 alkyl group or a C1-C4 alkoxy 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 ₂₃₃ ), and R ₂₃₃ represents the 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) An aryloxy group, and 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) Alkyl mercapto group or aryl mercapto group, and specific examples include methylthio group, ethylthio group, phenylthio group, p-methylphenylthio group and the like.
(6) A group represented by the following general formula (14).
However, in said formula (14), _R233 and _R234 represent a hydrogen atom, the alkyl group defined by said (2), or an aryl group, respectively. As said aryl group, a phenyl group, a biphenyl group, or a naphthyl group is mentioned, for example, These may contain a C1-C4 alkoxy group, a C1-C4 alkyl group, or a halogen atom as a substituent. R ₂₃₃ and R ₂₃₄ may form a ring together.

Specific examples of R ₂₃₃ and R ₂₃₄ include an amino group, a diethylamino group, an N-methyl-N-phenylamino group, an N, N-diphenylamino group, an N, N-di (tolyl) amino group, and a dibenzylamino group. , Piperidino group, morpholino group, pyrrolidino group and the like.
(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 ₁₄₁ and Ar ₁₄₂ include a divalent group derived from the aryl group represented by Ar ₁₄₃ and Ar ₁₄₄ .

  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 to C12, preferably C1 to C8, more preferably a C1 to C4 linear or branched alkylene group. These alkylene groups further include a fluorine atom and a hydroxyl group. , 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. It may be. Specific examples include a cyclohexylidene group, a cyclohexylene group, and a 3,3-dimethylcyclohexylidene group.
The substituted or unsubstituted alkylene ether group represents ethyleneoxy, propyleneoxy, ethylene glycol, propylene glycol, diethylene glycol, tetraethylene glycol, tripropylene glycol, and the alkylene ether group alkylene group is a hydroxyl group, a methyl group, an ethyl group. And the like.

The vinylene group is represented by the following general formula (15).
However, in the above formula _{(15), R 235} is hydrogen, an alkyl group (said (2) the same as the alkyl group, as defined), an aryl group (same as the aryl group represented by _{Ar 143, Ar 144)} , A represents 1 or 2, and b represents an integer of 1 to 3.

In the general formulas (12) and (13), Z represents any one of a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, and an alkyleneoxycarbonyl divalent 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 divalent group include the divalent group of the alkylene ether group in X. Examples of the alkyleneoxycarbonyl divalent group include a caprolactone-modified divalent group.
Moreover, as the polymerizable compound having the charge transport structure, a compound represented by the following general formula (16) is more preferable.

However, in said Formula (16), o, p, q is an integer of 0 or 1, respectively, Ra represents either a hydrogen atom or a methyl group, Rb and Rc are respectively C1-C1. 6 alkyl groups, each of which may be the same or different. s and t represent an integer of 0 to 3.
Za represents any one of a single bond, a methylene group, an ethylene group, and a group represented by the following chemical formula (17).

  The compound represented by the general formula (16) is particularly preferably a compound having a methyl group or an ethyl group as a substituent for Rb and Rc.

  The polymerizable compound having a monofunctional charge transport structure represented by the general formulas (12), (13), and (16), particularly, (16) is polymerized with a carbon-carbon double bond opened on both sides. Therefore, in a polymer which is not a terminal structure but is incorporated in a chain polymer and crosslinked by polymerization with a tri- or higher functional polymerizable monomer, it exists in the main chain of the polymer, and the main chain -Present in a cross-linked chain between main chains (this cross-linked chain includes an inter-molecular cross-linked chain between one polymer and another polymer, and a site with a main chain folded in one polymer) There are intramolecular cross-linked chains that are cross-linked with other sites derived from polymerized monomers at positions away from this in the main chain), but they are also present in the cross-linked chain even if they are present in the main chain Even if the triarylamine structure suspended from the chain portion is in a radial direction from the nitrogen atom, It has at least three aryl groups to be arranged and is bulky, but it is not directly bonded to the chain part and is suspended from the chain part via a carbonyl group or the like, so that it has flexibility in steric positioning. Since they are fixed, these triarylamine structures can be arranged spatially adjacent to each other in the polymer, so that there is little structural distortion in the molecule and the surface layer of the electrophotographic photosensitive member. In some cases, it is presumed that an intramolecular structure that is relatively free from interruption of the charge transport pathway can be adopted.

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

  The polymerizable compound having the charge transporting structure is important for imparting the charge transport performance of the protective layer, and the content of this component is 20% by mass to 80% by mass with respect to the protective layer. Preferably, 30 mass%-70 mass% is more preferable. When the content is less than 20% by mass, the charge transporting performance of the protective layer cannot be sufficiently maintained, and deterioration of electrostatic characteristics such as a decrease in sensitivity and an increase in residual potential may be observed with repeated use. If it exceeds 80% by mass, the content of the polymerizable compound not having the charge transport structure is relatively lowered, the crosslinking density is lowered, and high wear resistance may not be exhibited. The electrical properties and abrasion resistance required vary depending on the process used, and the film thickness of the protective layer varies accordingly. However, it cannot be said unconditionally, but considering the balance of both properties, it is in the range of 30% to 70% by mass. Is most preferred.

  Although these polymerizable compounds having a charge transporting structure cannot be isolated because they are cured, they can be isolated by using a method such as FT-IR even if they cannot be isolated. Therefore, the concentration ratio of the charge transport material can be obtained.

  As explained above, a polymerizable compound having a charge transporting structure having three or more polymerizable functional groups and a polymerizable compound having a charge transporting structure having one polymerizable functional group are cured. Are particularly effective, but it is also possible to use monofunctional and bifunctional polymerizable compounds, which may be very effective depending on the material. As these polymerizable compounds, known compounds can be used.

  Examples of the monofunctional polymerizable monomer include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, 2-ethylhexyl carbitol acrylate, 3-methoxybutyl acrylate, benzyl acrylate, Examples include cyclohexyl acrylate, isoamyl acrylate, isobutyl acrylate, methoxytriethylene glycol acrylate, phenoxytetraethylene glycol acrylate, cetyl acrylate, isostearyl acrylate, stearyl acrylate, and styrene monomer.

  Examples of the bifunctional 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, neopentyl glycol diacrylate, and the like.

  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, Siloxane repeating units described in JP-A-60503 and JP-B-6-45770: 20-70 acryloyl polydimethylsiloxane ethyl, methacryloyl polydimethylsiloxane ethyl, acryloyl polydimethylsiloxane propyl, acryloyl polydimethylsiloxane butyl, diacryloyl polydimethyl Examples include vinyl monomers having a polysiloxane group such as siloxane diethyl, acrylates and methacrylates.

  Examples of the polymerizable oligomer include epoxy acrylate, urethane acrylate, and polyester acrylate oligomers.

  Moreover, in order to advance this hardening reaction efficiently as needed, you may contain a polymerization initiator in a protective layer coating liquid.

  Examples of the thermal polymerization initiator include 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, lauroyl peroxide, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) B) Peroxide-based initiators such as propane, azo-based compounds such as azobisisobutylnitrile, azobiscyclohexanecarbonitrile, methyl azobisisobutyrate, azobisisobutylamidine hydrochloride, 4,4′-azobis-4-cyanovaleric acid Initiators are mentioned.

  Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1,2-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, 1 Benzophenone photopolymerization initiators such as 2-benzoylbenzene, thioxanthones such as 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone As photopolymerization initiators and other photopolymerization initiators, ethyl anthraquinone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 2,4,6-trimethylbenzoyl Phenylethoxyphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10 -Phenanthrene, an acridine type compound, a triazine type compound, an imidazole type compound is mentioned. 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. Content of a polymerization initiator is 0.5-40 mass parts with respect to 100 mass parts of total inclusions which have polymerizability, Preferably it is 1-20 mass parts.

  Furthermore, as the protective layer, additives such as various plasticizers (added for the purpose of stress relaxation and adhesion improvement), leveling agents, antioxidants, light stabilizers, ultraviolet absorbers, and the like are added as necessary. Can be contained. 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. To 20% by mass or less, preferably 10% by mass or less. 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. On the other hand, 3% by mass or less is appropriate. In addition, as additives such as antioxidants, light stabilizers, ultraviolet absorbers, phenolic compounds, hindered phenolic compounds, hindered amine compounds, paraphenylenediamines, hydroquinones, organic sulfur compounds, All additives such as organic phosphorus compounds, benzophenones, salsylates, benzotriazoles, quenchers (metal complex salts) and the like such as conventionally known antioxidants, light stabilizers and ultraviolet absorbers are included. In addition, a compound having an alkylamino group contained in the charge transport layer can be added to the protective layer, which may be very effective.

The protective layer contains at least the filler, the polycarboxylic acid compound, the polymerizable compound having the charge transporting structure, and the coating liquid containing the polymerizable compound not having the charge transporting structure, It is formed by coating on the layer, followed by curing and drying. When the polymerizable compound is a liquid, such a coating liquid can be applied by dissolving other components in the liquid, but if necessary, it is diluted with a solvent and applied.
As the solvent used, tetrahydrofuran and cyclopentanone are preferable. In addition, 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 dioxane and propyl ether, Halogens such as dichloromethane, dichloroethane, trichloroethane and chlorobenzene, aromatics such as benzene, toluene and xylene, and cellosolvs such as methyl cellosolve, ethyl cellosolve and cellosolve acetate may also be contained.

  It is effective if the tetrahydrofuran and cyclopentanone are contained in the entire layer of the electrophotographic photosensitive member. In particular, as described above, cyclopentanone is used as a dispersion medium for the filler in the protective layer. , It is most effective to contain. Specifically, dispersion is performed in a state containing the filler, the polycarboxylic acid compound, and the cyclopentanone, and the resulting mill base is converted into at least the polymerizable compound having the charge transport structure and the charge transport. The coating liquid which forms the said protective layer can be obtained by mixing and stirring the solution containing the polymeric compound which does not have a crystalline structure, and the said tetrahydrofuran. Of course, other additives such as the above plasticizers, leveling agents, antioxidants, compounds having alkylamino groups, light stabilizers, ultraviolet absorbers, polymerizable compounds having a charge transporting structure, and charge transporting properties are also included. It is also possible and effective to contain it in a solution containing a polymerizable compound having no structure. As described above, when the cyclopentanone is used as a dispersion medium for the filler, a high effect for improving dispersibility can be obtained even in a very small amount.

  Although there is no restriction | limiting in particular as solid content concentration in the coating liquid which forms the said protective layer, 5 mass%-40 mass% are preferable, and 10 mass%-30 mass% are more preferable. When the solid content concentration is less than 5% by mass, there is a risk of causing inhibition of curing due to an increase in residual solvent and an increase in the amount of elution of the charge transport material in the charge transport layer into the protective layer. On the other hand, when the solid content concentration exceeds 40% by mass, the film quality of the protective layer may deteriorate or a coating film defect may occur.

  The method for coating the protective layer is not particularly limited, and can be performed using a conventionally known method such as a dip coating method, spray coating, bead coating, or ring coating method. In order to reduce the elution amount of the substance, it is preferable to reduce the solvent content at the time of forming the coating layer and the contact time with the solvent, and in that respect, the spray coating, the ring that regulates the amount of coating liquid A coating method is preferred.

After applying the protective layer coating liquid, the protective layer is formed by applying energy from the outside to be cured. The external energy used at this time includes heat, light, and radiation.
The heat energy is applied by heating from the coating surface side or the support side using a gas such as air or nitrogen, steam, various heat media, infrared rays, or electromagnetic waves. The heating temperature is preferably 100 ° C. or higher and 170 ° C. or lower. When the heating temperature is lower than 100 ° C., the reaction rate is slow and the curing reaction is not completely completed. When the temperature is higher than 170 ° C., the curing reaction proceeds non-uniformly, and a large strain, a large number of unreacted residues, and reaction termination terminals are generated in the protective layer. In order to proceed the curing reaction uniformly, it is also effective to complete the reaction by heating at a relatively low temperature of less than 100 ° C. and then heating to 100 ° C. or more.

As the energy of the light, a UV irradiation light source such as a high-pressure mercury lamp or a metal halide lamp mainly having an emission wavelength in ultraviolet light can be used, but visible light is matched to the absorption wavelength of the polymerizable substance and the photopolymerization initiator. A light source can also be selected. Irradiation light amount, 50 mW / cm ² or more 1,000 mW / cm ² or less, and it takes time for the curing reaction is less than 50 mW / cm ^2. If it is higher than 1,000 mW / cm ² , the reaction progresses unevenly, local flaws occur on the surface of the curable protective layer, and many unreacted residues and reaction termination ends occur. In addition, internal stress increases due to rapid crosslinking, which causes cracks and film peeling. Examples of radiation energy include those using electron beams. Among these energies, those using heat and light energy are useful because of the ease of reaction rate control and the simplicity of the apparatus.

The electrophotographic photosensitive member can obtain a high effect when the protective layer is cured. Whether or not the protective layer is cured may be determined whether or not it is insoluble in an organic solvent.
As a method for testing the solubility in an organic solvent, one drop of an organic solvent having high solubility in a high molecular weight substance, such as tetrahydrofuran or dichloromethane, is dropped on the protective layer of the electrophotographic photosensitive member, followed by exposure to light after natural drying. It can be determined by observing a change in body surface shape with a stereomicroscope. Dissolving photoconductors have a phenomenon in which the central part of the droplet becomes concave and the surroundings swell up in reverse, the phenomenon that the charge transport material precipitates and cloudiness or cloudiness occurs due to crystallization, the surface swells and then shrinks. There are changes in the phenomena that occur. On the other hand, insoluble photoreceptors do not exhibit the above-mentioned phenomena and do not show any change from before dropping.

  Although there is no restriction | limiting in particular as thickness of the said protective layer, 1 micrometer or more and 5 micrometers or less are preferable, and 2 micrometers or more and 4 micrometers or less are preferable. If it is thicker than necessary, for example, if it exceeds 5 μm, as described above, the residual potential, the exposed portion potential increase, sensitivity reduction, cracks or film peeling may occur. In the electrophotographic photosensitive member, the protective layer has very high wear resistance and scratch resistance, and since the influence of curing inhibition of the protective layer is small, the thickness of the protective layer can be further reduced. However, if the protective layer is less than 1 μm, the film quality deteriorates, the cross-linking reaction becomes non-uniform, or image blur occurs when a charge transport material having a low ionization potential is used for the charge transport layer. Therefore, the thickness is preferably 1 μm or more.

Further, the surface roughness of the protective layer greatly affects foreign matter adhesion such as cleaning properties and filming. On the surface of the protective layer, the ten-point average roughness Rz based on JIS B0601 (1994) is set to 0.3 μm to 1.0 μm, or the average interval Sm of the unevenness existing on the surface is 0.3 μm to By setting the thickness to 1.0 mm, cleaning properties and foreign matter adhesion are greatly improved.
The ten-point average roughness Rz is defined as the sum of the average of the highest peak height from the highest peak to the fifth highest in the roughness curve and the average of the fifth highest valley depth from the deepest bottom. The average interval Sm between the irregularities is defined as the average length of the contour curve elements in the reference length.
The electrophotographic photosensitive member can obtain a greater effect by setting both Rz and Sm within the numerical range. This is because a large swell shape is formed by increasing the horizontal Sm while maintaining the Rz in the vertical direction of the electrophotographic photosensitive member. The microscopic uneven shape by the filler addition and the macroscopic swell It is considered that this is because the behavior of the cleaning blade is stabilized due to the coexistence of the uneven shape.

If Rz exceeds 1.0 μm, the cleaning properties of the recesses may be deteriorated and foreign matter may easily remain, and if it is less than 0.3 μm, the surface of the electrophotographic photosensitive member (protective layer surface) is smooth. , The contact area with the cleaning blade increases, the behavior of the cleaning blade becomes unstable, and there is a risk of causing poor cleaning.
Further, if the Sm exceeds 1.0 μm, a potential difference due to film thickness unevenness is visually recognized on the image, which may cause a reduction in image quality. If the Sm is less than 0.3 μm, a macroscopic uneven shape is formed. As a result, the durability of the blade deteriorates, such as the behavior of the cleaning blade becoming unstable and the chipping of the cleaning blade easily occurring. As a result, there is a risk that cleaning failure will occur early.

The Rz and Sm can be measured according to JIS B0601 (1994) using a surface roughness meter Surfcom 1400D manufactured by Tokyo Seimitsu Co., Ltd.
As an example of the measurement procedure, the evaluation length in the longitudinal direction (axial direction) of the photosensitive drum is set to 5.0 mm, for example, and four points are obtained when the photosensitive drum is set at an interval of about 90 ° in the circumferential direction. Measurement at the evaluation length is performed at the position.
At this time, measurement at four positions in the circumferential direction of the photosensitive drum is performed by (1) a central position in the longitudinal direction of the photosensitive drum, and (2) the central position and one longitudinal end of the photosensitive drum. And (3) an intermediate position between the central position and the other end in the longitudinal direction of the photosensitive drum. Find Sm. However, this is only an example, and any apparatus and conditions can be used as long as the equivalent measurement is possible.

The method for controlling the surface roughness of the protective layer is not particularly limited, and is controlled by the coating conditions, the method of controlling by adding an additive to the coating liquid, and the solid content of the coating liquid. Any method such as a method and a method of mechanically forming roughness after coating may be used. However, the method of forming roughness after coating is costly and relatively difficult to form the surface roughness. Therefore, a method of controlling by coating conditions, additives, liquid solids, etc. is preferable, and a method of controlling by coating conditions is more preferable.
As a method of controlling under the coating conditions, it is preferable to use a spray coating method as the coating method, and the surface roughness can be easily controlled by this condition. For example, it is possible to freely control the surface roughness according to conditions such as the atomizing air pressure during spray coating, the liquid discharge amount, the spray distance, and the number of times of coating. In addition, as a control method using an additive, for example, the surface roughness can be effectively reduced by adding the leveling agent in the coating liquid, adding a solvent that is not compatible with the coating liquid, or the solid content of the liquid. It is possible to control. In addition, it is possible and effective to control a touch drying time immediately after coating or to spray a solvent or air immediately after coating.

  Next, the case where a urethane resin is used as the curable resin will be briefly described. As the urethane resin, a conventionally known material can be used. The urethane resin is also excellent in wear resistance and can be used effectively as the protective layer.

The urethane resin has high wear resistance, good electrostatic characteristics, excellent film quality, and is effective for enhancing the durability and image quality of the photoreceptor.
There is no restriction | limiting in particular as said urethane resin, According to the objective, it can select suitably, For example, it can form by combining the polyol which is an active hydrogen component, and the polyvalent isocyanate which is a hardening | curing agent.
The polyol is not particularly limited, and may be a polyether polyol such as polyalkylene oxide, a polyester polyol such as an aliphatic polyester having a hydroxyl group at the terminal, an acrylic polymer polyol such as a hydroxymethacrylate copolymer, an epoxy resin, or the like. Known examples include epoxy polyols, fluorine-containing polyols, polycarbonate diols having a polycarbonate skeleton.

The polyol is preferably bifunctional or higher, preferably trifunctional or higher, because the curing density is improved, the three-dimensional network structure becomes stronger, and as a result, the curability is increased and the film strength is increased.
As the molecular weight of the polyol, those having a molecular weight of 100 to 150 are widely used. However, depending on the curing conditions, the volume shrinkage increases, and the film quality may deteriorate. In this case, in order to alleviate the volume shrinkage at the time of curing, a method in which a polyol having a molecular weight of 1,000 or more is separately contained and cured (Japanese Patent No. 3818585) is disclosed, which is also preferable in the present invention. Can be used.

Examples of the polyvalent isocyanate of the curing agent used together with the urethane resin include general isocyanate materials. However, those that do not discolor the film over time are preferred.
Examples of the polyvalent isocyanate include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), xylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), bis (isocyanate methyl) cyclohexane (HXDI), trimethyl. Isocyanate compounds such as hexamethylene diisocyanate (TMDI), HDI-trimethylolpropane adduct, HDI-isocyanate, HDI-biuret, XDI-trimethylolpropane adduct, IPDI-trimethylolpropane adduct, IPDI-isocyanurate Well-known things, such as polyisocyanate, such as these, can be illustrated.
Examples of the isocyanate having an amide bond include known ones such as an HDI-trimethylolpropane adduct, an IPDI-trimethylolpropane adduct, an HDI-biuret and can be used alone or in combination.
The ratio (NCO / OH ratio) between the number of NCO groups of the isocyanate and the number of OH groups of the polyol is preferably 1.0 to 1.5.

  Examples of the reactive compound having a charge transporting structure include polyols having the above-described charge transporting structure in the same structure, and other functional groups for curing reaction with polyisocyanate (for example, amino group, —SH group, etc.) Any known material can be used as long as it has a plurality of active hydrogen group-containing groups or polyhalogen-substituted siloxanes, polyalkoxy group-substituted siloxanes, etc. that hydrolyze with moisture in the air to generate Si-OH groups. As described above, the charge transporting structure may include either or both of the hole transporting property and the electron transporting property, and among them, a compound having a triarylamine structure is particularly effective. Moreover, a hydroxyl group is common as a functional group for the curing reaction. An example of a reactive compound having a triphenylamine structure is shown below.

With respect to the filler to be added, various additives and the like, and a method for forming the protective layer, materials and methods described for acrylic / methacrylic resins can be used.
As described above, there are many examples in which a curable resin is used for the protective layer. However, the present invention is not limited thereto, and any known curable resin can be used favorably in the present invention. is there.

<Underlayer>
As the electrophotographic photosensitive member, the undercoat layer can be provided between a bona fide conductive support and the charge generation layer, if necessary.
As the undercoat layer, a resin is generally used as a main component. However, considering that a charge generation layer and a charge transport layer are coated on the resin with a solvent, these resins are generally used for a general organic solvent. It is preferable to use a resin having a high solvent resistance.
Such resins are not particularly limited, and are water-soluble resins such as polyvinyl alcohol, casein and sodium polyacrylate, alcohol-soluble resins such as copolymerized polyamide (copolymerized nylon) and methoxymethylated polyamide (nylon), and polyurethane. Curable resins that form a three-dimensional network structure, such as melamine resin, phenol resin, alkyd-melamine resin, isocyanate, and epoxy resin.

The undercoat layer preferably contains a metal oxide in order to prevent moiré and reduce residual potential. Here, moire is a type of image defect in which interference fringes called moire are formed in an image due to optical interference when writing with coherent light such as laser light. Basically, it is necessary to contain a material having a large refractive index in order to prevent the occurrence of moire by scattering the incident laser light by the undercoat layer. In order to prevent moiré, a configuration in which an inorganic pigment is dispersed in a binder resin is most effective.
As the inorganic pigment, a white pigment is effectively used, and a metal oxide, for example, titanium oxide, zinc oxide, calcium fluoride, calcium oxide, silicon oxide, magnesium oxide, aluminum oxide, tin oxide, zirconium oxide, oxidized And indium.

The undercoat layer preferably has a function of moving a charge having the same polarity as the charge charged on the surface of the electrophotographic photosensitive member from the charge generation layer to the conductive support side in terms of reducing residual potential, Inorganic pigments also play that role. For example, in the case of a negatively charged electrophotographic photosensitive member, the undercoat layer can reduce the residual potential by having electronic conductivity.
As these inorganic pigments, the metal oxides described above are effectively used, but the effect of reducing the residual potential by using an inorganic pigment with low resistance or increasing the addition ratio of the inorganic pigment to the binder resin. On the other hand, the effect of suppressing soiling may be reduced. Therefore, it is necessary to achieve both suppression of background stains and reduction of residual potential by properly using the inorganic pigment or adjusting the addition amount depending on the layer structure and thickness of the undercoat layer in the electrophotographic photoreceptor. It is. In consideration of prevention of moire, increase in residual potential, and suppression of soiling, titanium oxide is particularly preferable among the metal oxides.

As the undercoat layer, a coating dispersion can be obtained by wet-dispersing the binder resin and the inorganic pigment (metal oxide) as main components and including a solvent.
There is no restriction | limiting in particular as said solvent, Acetone, methyl ethyl ketone, methanol, ethanol, butanol, cyclohexanone, cyclopentanone, a dioxane, etc., and these mixed solvents are mentioned. In particular, when cyclopentanone is partially contained, an effect of enhancing the dispersibility of the inorganic pigment can be obtained, which may be effective for scumming resistance and stability of the exposed portion potential.
As said inorganic pigment, it can disperse | distribute in a coating liquid by a conventionally well-known method, for example, a ball mill, a sand mill, an attrir, etc. with a solvent and binder resin.
The binder resin may be added before or after dispersion. Further, if necessary, a dispersant may be added for the purpose of enhancing the dispersibility of the chemicals, additives, curing accelerators, and inorganic pigments necessary for curing (crosslinking). Using these coating liquids, they are formed on a conductive substrate using a conventionally known method such as dip coating, spray coating, ring coating, beat coating, or nozzle coating. After the application, it can be produced by drying or heating, and if necessary, drying or curing by a curing treatment such as light irradiation.
There is no restriction | limiting in particular as thickness of the said undercoat layer, Although it changes with kinds of inorganic pigment to contain, 0 micrometer-10 micrometers are preferable, and 2 micrometers-7 micrometers are more preferable.

Further, an intermediate layer may be further provided between the conductive support and the undercoat layer or between the undercoat layer and the charge generation layer.
The intermediate layer is added to suppress the injection of holes from the conductive support, and the main purpose is to prevent scumming.
As the intermediate 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 the method for forming the intermediate layer, a method similar to the method for forming the undercoat layer and a known coating method are employed. The thickness of the intermediate layer is preferably 0.05 μm to 2 μm.
By adopting a two-layer configuration of the intermediate layer and the undercoat layer, it is possible to remarkably enhance the background stain suppression effect.

Here, the configuration of the electrophotographic photosensitive member will be described with reference to the drawings.
FIG. 1 shows an electrophotographic photoreceptor in which a charge generation layer (1015), a charge transport layer (1016), and a protective layer (1013) are laminated in this order on a conductive support (1011). Further, as shown in FIG. 2, an undercoat layer (1034) may be provided between the charge generation layer (1035) and the conductive support (1031). Note that (1033) is a protective layer and (1036) is a charge transport layer. Further, the undercoat layer may have a two-layer structure. Note that these layer configurations are representative, and the present invention is not limited to these layer configurations.

<Content of tetrahydrofuran and cyclopentanone>
In the electrophotographic photosensitive member, at least one of the layers laminated on the conductive support contains the tetrahydrofuran and the cyclopentanone, and the solid content of all layers laminated on the conductive support The content of is about 50 ppm to 10,000 ppm for the tetrahydrofuran and about 1 ppm to 100 ppm for the cyclopentanone.
If the content of the tetrahydrofuran and the cyclopentanone is higher than this, the residual potential and the exposed area potential are increased, and the electrostatic characteristics and potential characteristics fluctuate with the storage time of the electrophotographic photosensitive member, thereby inhibiting the curing. As a result, sufficient durability cannot be obtained, and image quality stability and durability are greatly affected. On the other hand, if it is less than this, the effect of containing the cyclopentanone will not be obtained substantially, various problems due to poor dispersion of the filler will occur, the adhesion of the protective layer Degradation occurs and peeling occurs, and the film quality of the protective layer is deteriorated to induce poor cleaning, wear resistance and scratch resistance are lowered, and durability is greatly reduced.
From such a viewpoint, the content of the tetrahydrofuran is preferably 200 ppm or more and 3,000 ppm or less, and the content of the cyclopentanone is preferably 2 ppm or more and 30 ppm or less.
The solid content of all layers laminated on the conductive support indicates the mass after drying of all the layers laminated on the conductive support.

In order to contain the cyclopentanone in a content of 1 ppm or more and 100 ppm or less with respect to the solid content of all layers laminated on the conductive support, the amount of the cyclopentanone contained in the coating liquid is There are adjustments, but that is not the only decision.
It varies depending on the curing conditions after coating the protective layer and the drying conditions of each layer, and it varies depending on whether the cyclopentanone is used as a dispersion medium or when it is simply added to the coating liquid, or with the tetrahydrofuran. The content of the cyclopentanone contained in the photoreceptor may be different depending on whether it is mixed with another solvent. Therefore, it is necessary to determine the addition amount of the cyclopentanone in consideration of the manufacturing method and conditions of the electrophotographic photosensitive member.

It is also effective to add a part of the cyclopentanone to the charge transport layer, the charge generation layer, the undercoat layer or the intermediate layer in addition to the protective layer. In particular, with respect to the charge generation layer and the undercoat layer in which the pigment is dispersed, effects such as increased dispersibility of the pigment and improved dispersion stability can be obtained.
However, problems such as residual potential and adhesion of the electrophotographic photosensitive member are most affected by the protective layer, and it is preferable that the cyclopentanone is contained in the protective layer in the largest amount. On the other hand, it is also effective to contain a part of the tetrahydrofuran in the charge transport layer, the charge generation layer, the undercoat layer or the intermediate layer, particularly in the charge transport layer and the protective layer. It is preferable to make it.
The content of the tetrahydrofuran and the cyclopentanone can be measured by various methods. In the present invention, a heat extraction gas chromatograph mass spectrometry method is used.
The sample can be measured by any method, such as a method of peeling the entire layer from the conductive support of the electrophotographic photosensitive member m, a method of cutting out the entire conductive support, but in order to measure a more accurate amount of solvent, Cut out the entire conductive support. As an apparatus used for the measurement, QP-2010 manufactured by Shimadzu Corporation was used. The heat extraction condition was 280 ° C. for 15 minutes, and Py-2020D manufactured by Frontier Laboratories was used as the heating device. As the column, ULTRA ALLOY-5 (L = 30 m, ID = 0.25 mm, Film = 0.25 μm) was used, and the column flow rate was 1.0 ml / min. The quantification of the amount of the solvent was carried out using a calibration curve which was prepared in the same manner for each solvent as a standard sample.

<Additives for each layer>
In the electrophotographic photoreceptor, in order to improve environmental resistance, the protective layer, the charge transport layer, the charge generation layer, the lower layer are specifically used for the purpose of preventing a decrease in sensitivity, an increase in residual potential, a decrease in charge, and the like. It is preferable to add an antioxidant, a plasticizer, a lubricant, an ultraviolet absorber, a leveling agent and the like to at least one of the pulling layer and the intermediate layer. Representative materials of these compounds are shown below.

Examples of the antioxidant that can be added to each layer include, but are not limited to, the following.
(A) Phenol compound 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, n-octadecyl-3- (4′- Hydroxy-3 ′, 5′-di-tert-butylphenol), 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-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4 -Hydroxybenzyl) benzene, te Lakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3′-bis (4′-hydroxy-3′-t-butyl) Phenyl) butyric acid] cricol ester, tocopherols and the like.
(B) Paraphenylenediamines N-phenyl-N′-isopropyl-p-phenylenediamine, N, N′-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylene Diamine, N, N′-di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine and the like.
(C) 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.
(D) Organic sulfur compounds dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, and the like.
(E) Organic phosphorus compounds Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine and the like.

Examples of the plasticizer that can be added to each layer include, but are not limited to, the following.
(A) Phosphate ester plasticizer Triphenyl phosphate, tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, trichloroethyl phosphate, cresyl diphenyl phosphate, tributyl phosphate, tri-2-ethylhexyl phosphate, Triphenyl phosphate and the like.
(B) Phthalate ester plasticizers Dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dibutyl phthalate, diheptyl phthalate, di-2-ethylhexyl phthalate, diisooctyl phthalate, di-n-octyl phthalate, phthalate Dinonyl acid, diisononyl phthalate, diisodecyl phthalate, diundecyl phthalate, ditridecyl phthalate, dicyclohexyl phthalate, butyl benzyl phthalate, butyl lauryl phthalate, methyl oleyl phthalate, octyl decyl phthalate, dibutyl fumarate, dioctyl fumarate etc.
(C) Aromatic carboxylic acid ester plasticizers Trioctyl trimellitic acid, tri-n-octyl trimellitic acid, octyl oxybenzoate and the like.
(D) Aliphatic dibasic ester plasticizer dibutyl adipate, di-n-hexyl adipate, di-2-ethylhexyl adipate, di-n-octyl adipate, adipic acid n-octyl-n-decyl , Diisodecyl adipate, dicapryl adipate, di-2-ethylhexyl azelate, dimethyl sebacate, diethyl sebacate, dibutyl sebacate, di-n-octyl sebacate, di-2-ethylhexyl sebacate, di-2 sebacate -Ethoxyethyl, dioctyl succinate, diisodecyl succinate, dioctyl tetrahydrophthalate, di-n-octyl tetrahydrophthalate and the like.
(E) Fatty acid ester derivatives butyl oleate, glycerin monooleate, methyl acetylricinoleate, pentaerythritol ester, dipentaerythritol hexaester, triacetin, tributyrin and the like.
(F) Oxyacid ester plasticizers Methyl acetyl ricinoleate, butyl acetyl ricinoleate, butyl phthalyl butyl glycolate, tributyl acetyl citrate and the like.
(G) Epoxy plasticizer Epoxidized soybean oil, epoxidized linseed oil, butyl epoxy stearate, decyl epoxy stearate, octyl epoxy stearate, benzyl epoxy stearate, dioctyl epoxy hexahydrophthalate, didecyl epoxy hexahydrophthalate, etc. .
(H) Dihydric alcohol ester plasticizers such as diethylene glycol dibenzoate and triethylene glycol di-2-ethylbutyrate.
(I) Chlorinated plasticizer Chlorinated paraffin, chlorinated diphenyl, chlorinated fatty acid methyl, methoxychlorinated fatty acid methyl, and the like.
(J) Polyester plasticizer Polypropylene adipate, polypropylene sebacate, polyester, acetylated polyester and the like.
(K) Sulfonic acid derivatives p-toluenesulfonamide, o-toluenesulfonamide, p-toluenesulfoneethylamide, o-toluenesulfoneethylamide, toluenesulfone-N-ethylamide, p-toluenesulfone-N-cyclohexylamide and the like.
(L) Citric acid derivatives Triethyl citrate, triethyl acetyl citrate, tributyl citrate, tributyl acetyl citrate, tri-2-ethylhexyl acetyl citrate, acetyl citrate-n-octyldecyl and the like.
(M) Others Terphenyl, partially hydrogenated terphenyl, camphor, 2-nitrodiphenyl, dinonylnaphthalene, methyl abietate and the like.

Examples of the lubricant that can be added to each layer include, but are not limited to, the following.
(A) Hydrocarbon compound Liquid paraffin, paraffin wax, microwax, low-polymerized polyethylene and the like.
(B) Fatty acid compounds Lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid and the like.
(C) Fatty acid amide compounds Stearylamide, palmitylamide, oleinamide, methylenebisstearamide, ethylenebisstearamide and the like.
(D) Ester compounds Fatty acid lower alcohol esters, fatty acid polyhydric alcohol esters, fatty acid polyglycol esters, and the like.
(E) Alcohol compounds Cetyl alcohol, stearyl alcohol, ethylene glycol, polyethylene glycol, polyglycerol and the like.
(F) Metal soap Lead stearate, cadmium stearate, barium stearate, calcium stearate, zinc stearate, magnesium stearate and the like.
(G) Natural wax Carnauba wax, candelilla wax, beeswax, whale wax, ibota wax, montan wax and the like.
(H) Others Silicone compounds, fluorine compounds, etc.

Examples of the ultraviolet absorber that can be added to each layer include, but are not limited to, the following.
(A) Benzophenone series 2-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2,2 ′, 4-trihydroxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 2,2′-dihydroxy-4- Methoxybenzophenone etc.
(B) Salsylates Phenyl salsylates, 2,4 di-t-butylphenyl 3,5-di-t-butyl 4-hydroxybenzoate, and the like.
(C) Benzotriazole series (2′-hydroxyphenyl) benzotriazole, (2′-hydroxy5′-methylphenyl) benzotriazole, (2′-hydroxy5′-methylphenyl) benzotriazole, (2′-hydroxy3) '-Tert-butyl 5'-methylphenyl) 5-chlorobenzotriazole and the like.
(D) Cyanoacrylate-based ethyl-2-cyano-3,3-diphenyl acrylate, methyl 2-carbomethoxy 3 (paramethoxy) acrylate, and the like.
(E) Quencher (metal complex)
Nickel (2,2′thiobis (4-t-octyl) phenolate) normal butylamine, nickel dibutyldithiocarbamate, nickel dibutyldithiocarbamate, cobalt dicyclohexyldithiophosphate and the like.
(F) HALS (hindered amine)
Bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2- [3- (3 5-di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6 6-tetramethylpyridine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4-dione, 4-benzoyloxy- 2,2,6,6-tetramethylpiperidine and the like.

(Image forming device)
The image forming apparatus of the present invention includes at least the electrophotographic photosensitive member of the present invention, a charging unit that charges the electrophotographic photosensitive member, and an exposing unit that forms an electrostatic latent image on the electrophotographic photosensitive member, Development means for developing the electrostatic latent image with toner, and transfer means for transferring the developed toner image to a recording medium. If necessary, the toner image transferred to the recording medium is heated and Fixing means for fixing on the transfer medium by pressing, cleaning means for removing the toner remaining on the electrophotographic photosensitive member after the transfer, and static electricity remaining on the electrophotographic photosensitive member after the transfer. It has neutralizing means for removing the latent image.
The image forming apparatus will be described in detail with reference to the drawings.

  FIG. 3 is a schematic view for explaining the image forming apparatus of the present invention. This is one representative example, and the present invention is not limited to this example. For example, all modifications described later are included in the present invention. The photoconductor (21) has a drum shape, but is not limited thereto, and may be in the form of a sheet or an endless belt, for example. (22) is a static elimination lamp, (23) is a charging charger, (24) is an image exposure unit, (25) is a developing unit, (26) is a pre-transfer charger, (27) is a registration roller, and (28) is a registration roller. Transfer paper, (29) is a transfer charger, (30) is a separation charger, (31) is a separation claw, (32) is a charger before cleaning, (33) is a fur brush, and (34) is a blade.

  As the charging means, for example, a corona discharge method for applying a high voltage to a wire typified by corotron, scorotron, etc., a solid discharge method for applying a high frequency high voltage to a planar electrode sandwiching an insulating plate instead of a wire, a roller A contact type roller charging method in which a high voltage is applied to a member having a shape and charging is performed in contact with the electrophotographic photosensitive member, and a proximity arrangement type in which the roller has a shape and is charged through a gap of 100 μm or less in an image forming region. Conventionally known chargers such as a roller charging method, a contact charging method in which charging is performed in contact with the electrophotographic photosensitive member using a brush, a film, a blade, or the like can be used.

  In the corona charging method, a high voltage is applied to a wire having a diameter of 50 to 100 μm, the surrounding air is ionized, and it is charged by moving it to an electrophotographic photosensitive member. Corona discharge systems are roughly classified into corotron and scorotron. The scorotron has a configuration in which screen electrodes (grids) are arranged on the corotron. The screen electrodes are arranged at a pitch of 1 to 3 mm and are spaced from the electrophotographic photosensitive member by 1 to 2 mm. As a result, even if the charging time becomes long, the charging potential is regulated by the voltage applied to the grid electrode, and the surface potential is saturated. Therefore, the charging potential can be controlled by the grid voltage, and uniform charging is possible. In order to cope with high speed, a double wire type in which two wires are stretched is particularly effective. Of the double wire types, a type in which two wires are partitioned is also effectively used. However, in order to prevent discharge between the wires or between the wire and the casing, it is necessary to provide a gap of 1.5 mm or more per 1 kV.

  The roller-shaped charging method is a method in which a voltage is applied to a conductive roller and brought into contact with an electrophotographic photosensitive member to give an electric charge. Compared with the corona charging method, the applied voltage is low, which is advantageous for downsizing of the apparatus, and has an advantage that the amount of generated ozone is very small. However, if it is used at a very high speed, the chargeability may be reduced due to contamination of the roller or the life of the roller. Further, even in the roller-shaped charging method, a proximity arrangement method in which the image forming area is not in contact with the electrophotographic photosensitive member is also effectively used. As a result, the charging roller is contaminated by the developer, paper powder, and the like through repeated use, and it is possible to suppress the occurrence of charge reduction, abnormal image generation, and wear. As a method for arranging the electrophotographic photosensitive member and the charging roller close to each other in the image forming region, there is a method of providing a gap in the non-image forming region of the charging roller or the electrophotographic photosensitive member. For example, as shown in FIG. 4, by providing a gap tape (gap forming member 51) having a uniform thickness in the non-image forming area of the charging roller (56), the gap can be maintained. Here, (55) is an electrophotographic photosensitive member, (52) is a metal shaft, (53) is an image forming area, and (54) is a non-image forming area. The gap between the electrophotographic photosensitive member and the charging roller is preferably small, and is 100 μm or less, more preferably 50 μm or less. By adopting a configuration in which the charging roller is not brought into contact with the electrophotographic photosensitive member, the discharge becomes uneven accordingly, and the charging of the electrophotographic photosensitive member may become unstable. On the other hand, it is preferable that the applied bias is charged by superimposing an alternating current component (AC) on a direct current component (DC), thereby significantly improving the charging stability.

As the exposure means, any means can be used as long as the irradiated light is absorbed by the charge generating material of the electrophotographic photosensitive member. The charged electrophotographic photosensitive member is exposed to light, and the light is absorbed by the charge generating material to generate a charge pair. The one charge moves to the surface and counteracts the surface charge, thereby static on the surface of the electrophotographic photosensitive member. An electrostatic latent image is formed.
The light source used as the exposure means is not particularly limited as long as the above conditions are satisfied. A light emitting diode (LED), a semiconductor laser (LD), electroluminescence (EL), a tungsten lamp, a halogen lamp, a mercury lamp, A fluorescent lamp, a sodium lamp, etc. can be used. Among these, the light emitting diode and the semiconductor laser are effective from the viewpoint of speeding up and downsizing the apparatus, and are most suitable for further enhancing the effect of the present invention.
In addition, these light sources are combined with various filters such as sharp cut filters, band pass filters, near infrared cut filters, dichroic filters, interference filters, and color temperature conversion filters in order to emit light in the desired wavelength range. It can also be used.

  As the exposure means, a multi-beam exposure means, particularly a surface emitting laser is particularly preferably used. In order to make the image forming apparatus compatible with high-speed image formation, it is necessary to increase the rotation speed of the polygon mirror of the rotating polyhedral body and increase the image scanning frequency in the sub-scanning direction. However, the rotational speed of the polygon mirror is also limited. In this case, a multi-beam scanning exposure method using a multi-beam recording head is used in which a plurality of beam light sources are arranged in the sub-scanning direction and a plurality of beams are scanned by one scan in the main scanning direction. In this method using a multi-beam recording head, for example, the number of rotations of the polygon mirror of the rotating polyhedral body required when only one beam light source is obtained by using n beam light sources is 1 / n. As a result, the speed can be increased by n times as compared with the case of a one-beam light source. Further, there is a margin in the scanning speed, and there is a great merit that the scanning density is increased by that amount, and high-speed and high-definition image output becomes possible.

  FIG. 5 shows an example of the multi-beam exposure means. A plurality of laser beams emitted from a light source (301) in which a plurality of light emitting points (301a) are arranged one-dimensionally or two-dimensionally are constrained in parallel or substantially parallel by a collimating lens (302), so that a cylindrical lens (303), It is deflected in the main scanning direction by a rotating polygon mirror (polygon mirror) (305) through an aperture (304). The laser beam deflected by the rotating polygon mirror (305) becomes convergent light by the scanning lens 1 (306a) and the scanning lens 2 (306b), and is exposed through the reflecting mirrors 1, 2, 3 (307a, 307b, 307c). The image is formed on the body surface (308) and scanned (309) in the main scanning direction. As the light source of the multi-beam exposure means, an edge emitting laser and a surface emitting laser can be used. In particular, the surface emitting laser can form a laser array in which the light emitting points are two-dimensionally arranged, and is effective in increasing the speed and size of the image forming apparatus and improving the resolution of the image. A combination of (302), (303), and (304) is referred to as a coupling optical system. The (a) part is an enlarged display of the light source, and the (b) part is an enlarged display of the scanning lines.

  When the multi-beam exposure means is used, the speed of the electrophotographic photosensitive member can be increased without being limited to the rotational speed of the polygon mirror. Further, the multi-beam exposure means can reduce the influence caused by the overlap of a plurality of laser beams, which is particularly preferable.

The developing unit develops the electrostatic latent image formed by the exposing unit with toner, and forms the toner image on the electrophotographic photosensitive member. When developing with a toner having the same polarity as the charged polarity of the electrophotographic photoreceptor, a negative image (reversal development) is obtained, and when developing with a toner of a different polarity, a positive image is obtained. Development includes a one-component development system that uses only toner and a two-component development system that uses a mixture of toner and carrier, and both can be used satisfactorily in the image forming apparatus.
Further, when a full color image is developed by superimposing a plurality of color toner images on the electrophotographic photosensitive member, if the method of developing in contact with the electrophotographic photosensitive member is used, the previously developed toner image is changed. May be disturbed. Therefore, for example, a developing means such as a jumping developing system that can be developed without contact with the electrophotographic photosensitive member is preferably used.

The transfer means is means for transferring the toner image formed on the electrophotographic photosensitive member to a transfer material (transfer medium such as paper). As the transfer means, a charger can be used. For example, a transfer charger (29) shown in FIG. 3 or a combination of the separation charger (30) is effective.
As a transfer system, the transfer unit is used to directly transfer the toner image from the electrophotographic photosensitive member to a transfer medium such as paper, and the toner image on the electrophotographic photosensitive member is once transferred to an intermediate transfer member. Then, there is an intermediate transfer method in which the image is transferred from the intermediate transfer member to a transfer medium such as paper. Either method can be used favorably. The latter intermediate transfer method is effective for high image quality and effective for full-color image forming apparatuses, but is disadvantageous for speeding up and downsizing of the apparatus. It is necessary to use properly.

  Further, there are a constant voltage method and a constant current method at the time of transfer, and either method can be used. However, the constant current method which can keep the transfer charge amount constant and is excellent in stability is more preferable. The higher the transfer current is, the higher the transferability becomes. In particular, when the linear velocity is increased, the transferability is lowered, so that an increase in the transfer current is effective.

The fixing unit is a step of fixing the toner image transferred onto the transfer medium such as paper on the transfer medium by heating and pressing.
As a fixing method, any method may be used as long as the toner can be fixed to the transfer medium. Specific examples include a method of heating and / or pressing, and there are a combination of a heating roller and a pressing roller, and a method of combining an endless belt.

The cleaning unit is a unit that removes toner remaining on the electrophotographic photosensitive member after the toner developed on the electrophotographic photosensitive member by the developing unit is transferred to a transfer medium by the transfer unit.
As the cleaning means, any method may be used as long as the residual toner can be removed from the electrophotographic photosensitive member. Specific means include a fur brush, a blade, or a combination thereof. In addition, a magnetic brush, an electrostatic brush, a magnetic roller, etc. are also used effectively. The cleaning process is contaminated by the adhesion of many foreign substances such as developer components, paper dust, and discharge products in addition to residual toner on the electrophotographic photosensitive member, which greatly affects image quality. It has a role to remove.

If the electrostatic latent image contrast remains on the electrophotographic photosensitive member even if the residual toner is removed by the cleaning unit, the neutralizing unit visualizes the contrast as a residual image or a ghost image in the next cycle. It is a means to remove them.
As the charge eliminating means, any means may be used as long as the charge generating substance can absorb the light emitted from the charge eliminating means. For example, a light emitting diode (LED), a semiconductor laser (LD), electroluminescence (EL), a tungsten lamp, a halogen lamp, a xenon lamp, a mercury lamp, a fluorescent lamp, a sodium lamp, and the like, and further an optical filter mentioned in the exposure means And may be used in combination. In addition to the light irradiation method, there is also a method of removing electricity by applying a reverse bias, which is preferable for suppressing electrostatic fatigue.

The image forming apparatus is not particularly limited, but it is preferable that the image forming apparatus further includes a lubricating substance applying unit that applies a lubricating substance to the surface of the electrophotographic photosensitive member. By applying the lubricating substance to the surface of the electrophotographic photosensitive member, it is possible to prevent the cleaning blade from turning over and the accompanying cleaning failure.
In addition, since the lubricating substance is applied to the surface of the electrophotographic photosensitive member, the surface of the electrophotographic photosensitive member is prevented from being deteriorated due to charging. That is, it is an effective method that can achieve both a long life and high image quality. Further, m, further improvement in wear resistance, scratch resistance and cleaning property of the electrophotographic photosensitive member can be realized.

The method for applying the lubricating substance is not particularly limited, and the lubricating substance is solidified, scraped with a brush and applied to the electrophotographic photosensitive member, and the lubricating substance is directly applied to the electrophotographic photosensitive member. There are many methods, such as a method of coating in contact with a body, a method of mixing the lubricant in powder form with the developer, and supplying and coating the surface of the electrophotographic photosensitive member in development. Of these, a method of scraping and applying with a brush is preferably used.
In order to uniformly apply the electrophotographic photosensitive member surface, a method in which a blade is brought into contact and the applied lubricating substance is spread is also preferably used. In this case, the blade may be used in combination with the cleaning blade, or a coating blade dedicated to the lubricating substance may be provided separately from the cleaning blade. The application of the lubricating substance is preferably carried out as a post-cleaning process, and the lubricating substance application means is preferably arranged at a position where it can be carried out as the post-process.

As the lubricating substance, any substance can be used as long as it adheres uniformly to the surface of the electrophotographic photosensitive member and as a result can impart lubricity to the surface of the electrophotographic photosensitive member. For example, materials such as waxes and lubricants can be used satisfactorily.
The waxes are not particularly limited, and ester waxes and olefin waxes are preferable.
The ester wax has an ester bond, and examples thereof include natural waxes such as carnauba wax, candelilla wax and rice wax, and montan wax.
Examples of the olefin wax include synthetic waxes such as polyethylene wax and polypropylene wax.
Examples of the lubricant include various fluorine-containing resins such as PTFE, PFA, and PVDF, silicone resins, polyolefin resins, zinc stearate, zinc laurate, zinc myristate, calcium stearate, and aluminum stearate. . Of these, zinc stearate is most preferable.

<Tandem type image forming apparatus>
The image forming apparatus is not particularly limited, but is preferably a tandem type.
The tandem type image forming apparatus is an image forming apparatus in which a plurality of image forming elements including at least the electrophotographic photosensitive member, the charging unit, the developing unit, and the transfer unit are arranged.
Corresponding to the developing sections that hold the plurality of color toners independently, the same number of electrophotographic photoreceptors are provided, whereby the development of each color is independently processed in parallel, and then each color toner The images are superimposed to form a full color image. Specifically, it is provided with a developing unit and electrophotographic photosensitive member of at least four colors of yellow (Y), magenta (M), cyan (C), and black (K) required for full-color printing. Compared with the conventional single drum system that outputs the process repeatedly, it achieves extremely high speed full-color printing, which is a particularly effective method in the present invention.

  FIG. 6 is a typical schematic diagram for explaining a tandem type full-color image forming apparatus. In FIG. 6, reference numerals (1C, 1M, 1Y, 1K) denote drum-shaped electrophotographic photosensitive members, and the electrophotographic photosensitive member of the present invention is used. This electrophotographic photosensitive member (1C, 1M, 1Y, 1K) rotates in the direction of the arrow in the figure, and at least in that order in the order of rotation, charging means (2C, 2M, 2Y, 2K), developing means (4C, 4M, 4Y) 4K) and cleaning means (5C, 5M, 5Y, 5K) are arranged.

  From the back side of the electrophotographic photosensitive member between the charging means (2C, 2M, 2Y, 2K) and the developing means (4C, 4M, 4Y, 4K), laser light (3C, 3M, 3Y, 3K) and an electrostatic latent image is formed on the electrophotographic photosensitive member (1C, 1M, 1Y, 1K). The four image forming elements (6C, 6M, 6Y, 6K) centering on the electrophotographic photoreceptors (1C, 1M, 1Y, 1K) are the transfer conveyance belt (10) as the transfer material conveyance means. Are juxtaposed along. The transfer conveyance belt (10) is electrophotographic photosensitive between the developing means (4C, 4M, 4Y, 4K) and the cleaning means (5C, 5M, 5Y, 5K) of each image forming unit (6C, 6M, 6Y, 6K). Transfer brushes (11C, 11M, 11M, 1M, 1K, 1K) for applying a transfer bias to the surface (back surface) of the transfer conveyance belt (10) that is in contact with the back side of the electrophotographic photosensitive member side. 11Y, 11K) are arranged. Each image forming element (6C, 6M, 6Y, 6K) is different in the color of the toner inside the developing device, and the others are the same in configuration.

  In the full-color image forming apparatus having the configuration shown in FIG. 6, the image forming operation is performed as follows. First, in each image forming element (6C, 6M, 6Y, 6K), the charging means (2C) in which the electrophotographic photosensitive member (1C, 1M, 1Y, 1K) rotates in the direction of the arrow (the direction along with the electrophotographic photosensitive member). 2M, 2Y, 2K), and then corresponding to each color image created by laser light (3C, 3M, 3Y, 3K) with an exposure unit (not shown) placed outside the electrophotographic photosensitive member An electrostatic latent image is formed. Next, the electrostatic latent image is developed by developing means (4C, 4M, 4Y, 4K) to form a toner image. Developing means (4C, 4M, 4Y, 4K) are developing means for developing with toners of C (cyan), M (magenta), Y (yellow), and K (black), respectively. 1C, 1M, 1Y, 1K) toner images of respective colors are superimposed on the transfer paper. The transfer paper (7) is fed out of the tray by a paper feed roller (8), temporarily stopped by a pair of registration rollers (9), and transferred and conveyed (10) in synchronism with the image formation on the electrophotographic photosensitive member. ). The transfer paper (7) held on the transfer conveyance belt (10) is conveyed, and the toner images of the respective colors are transferred at contact positions (transfer portions) with the electrophotographic photosensitive members (1C, 1M, 1Y, 1K). Is done.

  The toner image on the electrophotographic photosensitive member is generated by an electric field formed by a potential difference between the transfer bias applied to the transfer brush (11C, 11M, 11Y, 11K) and the electrophotographic photosensitive member (1C, 1M, 1Y, 1K). And transferred onto the transfer paper (7). Then, the recording paper (7) on which the four color toner images are passed through the four transfer portions is conveyed to the fixing device (12), where the toner is fixed, and is discharged to a paper discharge portion (not shown). Further, residual toner that is not transferred by the transfer unit and remains on the electrophotographic photosensitive members (1C, 1M, 1Y, 1K) is collected by a cleaning device (5C, 5M, 5Y, 5K).

  In the example of FIG. 6, the image forming elements are arranged in the order of C (cyan), M (magenta), Y (yellow), and K (black) from the upstream side to the downstream side in the transfer paper conveyance direction. However, it is not limited to this order, and the color order is arbitrarily set. Further, when a black-only document is created, it is particularly effective to use the present invention to provide a mechanism that stops the image forming elements (6C, 6M, 6Y) other than black. Furthermore, in FIG. 6, the charging means is in contact with the electrophotographic photosensitive member, but by providing a suitable gap (about 10 to 200 μm) between the two by the charging mechanism as shown in FIG. Fewer toner filming on the charging means is required, and it can be used satisfactorily.

(Process cartridge)
The process cartridge of the present invention integrally includes the electrophotographic photosensitive member of the present invention and at least one means selected from a charging means, an exposure means, a developing means, a transfer means, a cleaning means, and a charge eliminating means, It can be attached to and detached from the image forming apparatus main body.
As the charging unit, the exposure unit, the developing unit, the transfer unit, the cleaning unit, and the charge eliminating unit, the unit described for the image forming apparatus of the present invention can be applied. That is, these means may be fixedly incorporated in a copying machine, a facsimile, or a printer, and each image forming element may be incorporated in the apparatus in the form of a process cartridge.
A general example of the process cartridge is shown in FIG. The image forming process using this process cartridge will be described. The electrophotographic photosensitive member 101 corresponds to an exposure image on the surface thereof by rotating by the charging unit 102 and exposing 103 by the exposing unit (not shown) while rotating in the direction of the arrow. An electrostatic latent image is formed.
The electrostatic latent image is developed by the developing unit 104, and the obtained visible image is transferred to the recording medium 105 by the transfer unit 108 and printed out. Next, the surface of the electrophotographic photosensitive member after the image transfer is cleaned by the cleaning unit 107 and further neutralized by a neutralizing unit (not shown), and the above operation is repeated again.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example and a comparative example, the thought of this invention is not limited to the Example and comparative example illustrated here. In addition, the part in an Example represents a mass part unless there is particular notice.

<Synthesis of titanyl phthalocyanine crystal (pigment 1)>
First, a method for synthesizing titanyl phthalocyanine crystals will be described. The synthesis was performed according to Japanese Patent Application Laid-Open No. 2004-83859. That is, 292 parts of 1,3-diiminoisoindoline and 1,800 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.) until the washing solution becomes neutral. 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 filtration device were washed with tetrahydrofuran to obtain a wet cake of pigment. This was dried under reduced pressure (5 mmHg) at 70 ° C. for 2 days to obtain 8.5 parts of titanyl phthalocyanine crystals. This is designated as Pigment 1.
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. 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: 50 kV
Current: 30 mA
Scanning speed: 2 ° / min Scanning range: 3 ° -40 °
Time constant: 2 seconds

  Using a PSZ ball having a diameter of 0.5 mm in a commercially available bead mill disperser, the 2-butanone solution in which polyvinyl butyral was dissolved and the pigment 1 were introduced, and the rotor rotation speed was 3,000 r. p. m. Dispersion was carried out for 120 minutes to prepare a dispersion.

<Synthesis of azo pigments>
The synthesis of the azo pigment was performed according to the method described in Japanese Patent No. 3026645.

<Synthesis Example of Polymerizable Compound Having Charge Transporting Structure>
Synthesis of a polymerizable compound having a charge transporting structure was performed by the method described in Japanese Patent No. 3164426. Details will be described below.

(1) Synthesis of hydroxy group-substituted triarylamine compound (the following structural formula B) 113.85 g (0.3 mol) of a methoxy group-substituted triarylamine compound (the following structural formula A) and 138 g (0.92 mol) of sodium iodide To this, 240 ml of sulfolane was added and heated to 60 ° C. in a nitrogen stream. In this liquid, 99 g (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 1.5 L 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 g (yield = 80.4%) of white crystals of the following structural formula B was obtained.

Melting point: 64.0-66.0 ° C

(2) Triarylamino group-substituted acrylate compound (Exemplary Compound No. 54)
82.9 g (0.227 mol) of the hydroxy group-substituted triarylamine compound (Structural Formula B) obtained in (1) above was dissolved in 400 ml of tetrahydrofuran, and an aqueous sodium hydroxide solution (NaOH: 12.4 g) in a nitrogen stream. Water: 100 ml) was added dropwise. The solution was cooled to 5 ° C., and 25.2 g (0.272 mol) of acrylic acid chloride was added dropwise over 40 minutes. Thereafter, the reaction was completed by stirring at 5 ° C. for 3 hours. 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. As a result, 80.73 g (yield = 84.8%) of 54 white crystals were obtained.

Melting point: 117.5-119.0 ° C

Example 1
Using an intermediate layer coating solution, undercoat layer coating solution, charge generation layer coating solution, and charge transport layer coating solution having the following composition on an aluminum cylinder having an outer diameter of 60 mm, the dip coating method is used. It was applied and dried in an oven to form an intermediate layer of about 0.5 μm, an undercoat layer of about 2.5 μm, a charge generation layer of about 0.2 μm, and a charge transport layer of about 25 μm. The drying conditions for each layer were 130 ° C. for 10 minutes for the intermediate layer, 130 ° C. for 20 minutes for the undercoat layer, 90 ° C. for 20 minutes for the charge generation layer, and 120 ° C. for 20 minutes for the charge transport layer. The cyclopentanone used has a boiling point of 130.6 ° C. and tetrahydrofuran has a boiling point of 65 ° C.

<Intermediate layer coating solution>
N-methoxymethylated nylon: 5 parts (FR101: manufactured by Lead City Corporation)
Methanol: 70 parts n-butanol: 30 parts

<Coating liquid for undercoat layer>
Titanium oxide A: 50 parts (CR-EL, average primary particle size: about 0.25 μm, manufactured by Ishihara Sangyo Co., Ltd.)
Titanium oxide B: 20 parts (PT-401M, average primary particle size: about 0.07 μm, manufactured by Ishihara Sangyo Co., Ltd.)
Alkyd resin: 14 parts (Beckolite M6401-50, solid content: 50%, manufactured by Dainippon Ink & Chemicals, Inc.)
Melamine resin: 8 parts (L-145-60, solid content: 60%, manufactured by Dainippon Ink & Chemicals, Inc.)
2-butanone: 70 parts

<Coating liquid for charge generation layer>
8 parts of titanyl phthalocyanine (pigment 1) showing the X-ray diffraction spectrum of FIG. 8 (ionization potential 5.27 eV)
Polyvinyl butyral: 4 parts (BX-1, manufactured by Sekisui Chemical Co., Ltd.)
2-butanone: 400 parts

<Coating liquid for charge transport layer>
Polycarbonate: 10 parts (Z Polyca, manufactured by Teijin Chemicals Ltd.)
Charge transport material represented by CTM14 (molecular weight 700.98): 10 parts Tetrahydrofuran: 75 parts Silicone oil: 0.002 parts (1 cm ² / s (100 cSt), manufactured by Shin-Etsu Chemical Co., Ltd.)
Compound having an alkylamino group represented by the following structural formula: 1.0 part

  Next, a protective layer coating solution having the following composition was prepared by the following procedure. The filler was dispersed in a 70 cc glass pot by placing an alumina ball having a diameter of 5 mm, and further filled with a filler, a polycarboxylic acid compound and cyclopentanone, and dispersed for 24 hours (150 rpm) with a ball mill. Then, the mill base obtained by adding and stirring tetrahydrofuran and the solution which mixed other materials previously were mixed, and the coating liquid for protective layers was produced.

<Millbase>
Alumina filler: 8 parts (Sumicorundum AA-03, average primary particle size: 0.3 μm, manufactured by Sumitomo Chemical Co., Ltd.)
Polycarboxylic acid compound: 0.2 parts (BYK-P104, nonvolatile content 50%, manufactured by BYK Chemie)
Cyclopentanone: 8 parts Tetrahydrofuran: 12 parts

<Coating liquid for protective layer>
Millbase: 3 parts Radical polymerizable compound having no charge transport structure: 4 parts (KAYARAD TMPTA, Nippon Kayaku Co., Ltd., molecular weight: 296, functional group number: trifunctional, molecular weight / functional group number = 99)
Radical polymerizable compound having a monofunctional charge transport structure: 4 parts (Exemplary Compound No. 54)
Photopolymerization initiator: 0.5 part (1-hydroxy-cyclohexyl-phenyl-ketone, Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 50 parts

Using the obtained protective layer coating solution, a protective layer was formed by spray coating on the charge transport layer under the following coating conditions.
Spray distance: 50mm
Spray moving speed: 6mm / s
Drum rotation speed: 150rpm
Atomizing air pressure: 0.9 kg / cm ²
Atomization flow rate: 14L / min

After the protective layer is applied, it is naturally dried for 2 minutes, and then a Fusion UV lamp system using a metal halide lamp is used. The irradiation distance is 50 mm, the irradiation intensity is 500 mW / cm ² and the irradiation time is 50 seconds. Was cured by irradiation with light while maintaining at about 42 ° C. Further, drying was performed at 130 ° C. for 20 minutes to provide a protective layer having a thickness of about 3 μm.
The electrophotographic photosensitive member in Example 1 was manufactured as described above.

(Example 2)
In Example 1, the electrophotographic photosensitive member in Example 2 was produced in the same manner as in Example 1 except that the drying condition of the charge transport layer was changed from 120 ° C. for 20 minutes to 110 ° C. for 20 minutes.

(Example 3)
In Example 1, the electrophotographic photosensitive member in Example 3 was produced in the same manner as in Example 1 except that the drying condition of the charge transport layer was changed from 120 ° C. for 20 minutes to 130 ° C. for 20 minutes.

(Example 4)
In Example 1, the electrophotographic photosensitive member in Example 4 was produced in the same manner as in Example 1 except that the drying condition of the protective layer was changed from 130 ° C. for 20 minutes to 120 ° C. for 20 minutes.

(Example 5)
In Example 1, the electrophotographic photosensitive member in Example 5 was produced in the same manner as in Example 1 except that the drying condition of the protective layer was changed from 130 ° C. for 20 minutes to 140 ° C. for 20 minutes.

(Comparative Example 1)
In Example 1, the electrophotographic photosensitive member in Comparative Example 1 was produced in the same manner as in Example 1 except that the drying condition of the protective layer was changed from 130 ° C. for 20 minutes to 150 ° C. for 20 minutes.

(Example 6)
In Example 1, the electrophotographic photosensitive member in Example 6 was produced in the same manner as in Example 1 except that the drying condition of the protective layer was changed from 130 ° C. for 20 minutes to 130 ° C. for 15 minutes.

(Example 7)
In Example 1, the electrophotographic photosensitive member in Example 7 was produced in the same manner as in Example 1 except that the drying condition of the protective layer was changed from 130 ° C. for 20 minutes to 120 ° C. for 15 minutes.

(Comparative Example 2)
In Example 1, the electrophotographic photosensitive member in Comparative Example 2 was produced in the same manner as in Example 1 except that the drying condition of the protective layer was changed from 130 ° C. for 20 minutes to 110 ° C. for 10 minutes.

(Comparative Example 3)
Comparative Example 3 was carried out in the same manner as in Example 1 except that 12 parts of cyclopentanone was replaced with 8 parts of tetrahydrofuran in the preparation of the mill base of Example 1 and the total amount of tetrahydrofuran was changed from 12 parts to 20 parts. An electrophotographic photosensitive member was manufactured.

(Comparative Example 4)
An electrophotographic photosensitive member in Comparative Example 4 was produced in the same manner as in Example 1, except that 8 parts of cyclohexanone was used instead of 8 parts of cyclopentanone in the preparation of the mill base of Example 1.

(Comparative Example 5)
In the preparation of the mill base of Example 1, an electrophotographic photosensitive member in Comparative Example 5 was produced in the same manner as in Example 1 except that 8 parts of toluene was used instead of 8 parts of cyclopentanone.

(Example 8)
In the preparation of the mill base of Example 1, Example 12 was carried out in the same manner as in Example 1 except that 12 parts of tetrahydrofuran was replaced with cyclopentanone 12 and the total amount of cyclopentanone was changed from 8 parts to 20 parts. The electrophotographic photosensitive member in No. 8 was produced.

(Comparative Example 6)
In the protective layer coating solution of Example 1, the electrophotographic photosensitive film of Comparative Example 6 was prepared in the same manner as in Example 1 except that 40 parts of tetrahydrofuran and 10 parts of cyclopentanone were added instead of 50 parts of tetrahydrofuran. The body was manufactured.

Example 9
In Example 1, except that the charge transport material contained in the charge transport layer was changed from the compound (molecular weight 700.98) represented by CTM14 to the compound (molecular weight 700.98) represented by CTM13. In the same manner as in Example 1, the electrophotographic photoreceptor in Example 9 was produced.

(Example 10)
In Example 1, except that the charge transport material contained in the charge transport layer was changed from the compound represented by CTM14 (molecular weight 700.98) to the compound represented by CTM52 (molecular weight 881.23). In the same manner as in Example 1, the electrophotographic photoreceptor in Example 10 was produced.

(Example 11)
In Example 1, except that the charge transporting substance contained in the charge transporting layer was changed from the compound represented by CTM14 (molecular weight 700.98) to the compound represented by CTM54 (molecular weight 615.83). In the same manner as in Example 1, the electrophotographic photoreceptor in Example 11 was produced.

(Example 12)
In Example 1, the charge transport material contained in the charge transport layer was changed from the compound (molecular weight 700.98) represented by CTM14 to an α-phenylstilbene derivative (molecular weight 451.62) represented by the following structural formula. Except for this, the electrophotographic photoreceptor of Example 12 was produced in the same manner as Example 1.

(Example 13)
In Example 1, the charge transport material contained in the charge transport layer was changed from the compound represented by CTM14 (molecular weight 700.98) to the aminobiphenyl derivative represented by the following structural formula (molecular weight 379.51). Produced the electrophotographic photoreceptor in Example 13 in the same manner as in Example 1.

(Example 14)
In Example 1, except that the charge transport material contained in the charge transport layer was changed from the compound represented by CTM14 (molecular weight 700.98) to the benzidine derivative represented by the following structural formula (molecular weight 544.75). In the same manner as in Example 1, the electrophotographic photosensitive member in Example 14 was produced.

(Comparative Example 7)
The electrophotographic photosensitive member in Comparative Example 7 was produced in the same manner as in Example 1 except that the mill base was not added to the protective layer coating solution of Example 1 and the following composition was used.
<Coating liquid for protective layer>
Radical polymerizable compound having no charge transport structure: 4 parts caprolactone-modified dipentaerythritol hexaacrylate (KAYARAD DPCA-60, manufactured by Nippon Kayaku Co., Ltd.)
Molecular weight: 1263, number of functional groups: 6 functions, molecular weight / number of functional groups = 211
Radical polymerizable compound having a monofunctional charge transport structure: 4 parts (Exemplary Compound No. 54)
Photopolymerization initiator: 1 part 2,2-dimethoxy-1,2-diphenylethane-1-one (Irgacure 651, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 50 parts

(Comparative Example 8)
In the preparation of the mill base of Example 1, an electrophotographic photosensitive member in Comparative Example 8 was produced in the same manner as in Example 1 except that no polycarboxylic acid compound was added.

(Example 15)
The electrophotographic photosensitive member in Example 15 was obtained in the same manner as in Example 1 except that the radical polymerizable compound having no charge transporting structure in the coating liquid for protective layer of Example 1 was replaced with the following compound. Manufactured.
Radical polymerizable monomer having no charge transporting structure: 10 parts Caprolactone-modified dipentaerythritol hexaacrylate (KAYARAD DPCA-120, manufactured by Nippon Kayaku Co., Ltd., molecular weight: 1947, functional group number: 6 functional, molecular weight / functional group number = 325)

(Example 16)
The radically polymerizable compound having a charge transporting structure in the protective layer coating solution of Example 1 was converted into a monofunctional exemplified compound No. 1. 54 The electrophotographic photosensitive member in Example 16 was produced in the same manner as in Example 1 except that 7 parts and 3 parts of the bifunctional compound having the following structural formula were used.

(Example 17)
The protective layer coating solution in Example 1 was changed to a protective layer coating solution having the following composition, and was not subjected to curing treatment by light irradiation, and was heated and dried at 150 ° C. for 20 minutes after coating the protective layer. An electrophotographic photoreceptor in Example 17 was manufactured in the same manner as Example 1 except for the above.

<Coating liquid for protective layer>
Millbase in Example 1: 2 parts Isocyanate: 3 parts Sumijoule HT (HDI adduct) (manufactured by Sumika Bayern)
Polyol 1: 2 parts represented by the following structural formula
Polyol 2: 8 parts LZR170 (Fujikura Kasei Co., Ltd.)
Reactive compound having a charge transporting structure represented by the following structural formula: 10 parts
Tetrahydrofuran: 120 parts

(Comparative Example 9)
The protective layer coating solution in Example 1 was changed to a protective layer coating solution having the following composition, and was not subjected to curing treatment by light irradiation, except that it was heated and dried at 150 ° C. for 20 minutes after coating. In the same manner as in Example 1, the electrophotographic photoreceptor in Comparative Example 9 was produced.

<Coating liquid for protective layer>
Mill base in Example 1: 3 parts Polycarbonate: 10 parts (Z Polyca, manufactured by Teijin Chemicals Ltd.)
Charge transport material represented by the above compound CTM17 (molecular weight 672.92): 7 parts Compound having an alkylamino group represented by the following structural formula: 1 part
Tetrahydrofuran: 600 parts

(Example 18)
In Example 1, the charge generation layer was applied using a charge generation layer forming coating solution having the following composition, the drying condition was 130 ° C. for 20 minutes, and the charge transport layer was a charge transport layer coating solution having the following composition. An electrophotographic photosensitive member in Example 18 was produced in the same manner as in Example 1 except that the coating was used.

<Coating liquid for charge generation layer>
A PSZ ball having a diameter of 10 mm was used in a ball mill disperser, a cyclohexanone solution in which polyvinyl butyral was dissolved, and the following azo pigment were added, and the rotational speed was 85 r. p. m. Was dispersed for 7 days to prepare a dispersion.
Asymmetric bisazo pigment represented by the following structural formula: 5 parts
Polyvinyl butyral: 1.5 parts (BM-S, manufactured by Sekisui Chemical Co., Ltd.)
Cyclohexanone: 250 parts 2-butanone: 100 parts

<Coating liquid for charge transport layer formation>
Polycarbonate: 10 parts (Z Polyca, manufactured by Teijin Chemicals Ltd.)
Charge transport material represented by the above compound CTM17 (molecular weight: 672.92): 7 parts Silicone oil: 0.002 parts (1 cm ² / s (100 cSt), manufactured by Shin-Etsu Chemical Co., Ltd.)
Tetrahydrofuran: 100 parts Antioxidant represented by the following structural formula: 0.07 parts

(Example 19)
An electrophotographic photosensitive member in Example 19 was produced in the same manner as in Example 18 except that 250 parts of cyclohexanone was replaced with 250 parts of cyclopentanone in the coating solution for charge generation layer of Example 18.

(Example 20)
In Example 1, the electrophotographic photosensitive member in Example 20 was produced in the same manner as in Example 1 except that the filler contained in the protective layer coating solution was replaced with the following filler.
α-alumina: 2 parts (Sumicorundum AA-07, average primary particle size: 0.7 μm, manufactured by Sumitomo Chemical Co., Ltd.)

(Example 21)
In Example 1, the electrophotographic photosensitive member in Example 21 was produced in the same manner as in Example 1 except that the filler contained in the protective layer coating solution was replaced with the following filler.
Silica: 1 part (SO-E2, average primary particle size: 0.5 μm, manufactured by Admatechs)

(Example 22)
Example 22 is the same as Example 1 except that the atomizing air pressure, which is the coating condition of the protective layer in Example 1, was changed from 0.9 kg / cm ² to 1.1 kg / cm ² . An electrophotographic photoreceptor was produced.

(Example 23)
Example 23 is the same as Example 1 except that the atomizing air pressure, which is the coating condition of the protective layer in Example 1, was changed from 0.9 kg / cm ² to 0.8 kg / cm ² . An electrophotographic photoreceptor was produced.

(Example 24)
An electrophotographic photoreceptor in Example 24 was produced in the same manner as in Example 1 except that the amount of tetrahydrofuran added in the protective layer coating solution of Example 1 was changed from 50 parts to 20 parts.

<Evaluation of dispersion stability of filler>
For each of the protective layer coating liquids in Examples 1 to 24 and Comparative Examples 1 to 9, the dispersion stability of the filler was evaluated.
For evaluation of dispersion stability, a dispersion stability analyzer “LUMiSizer612” manufactured by RUFUTO was used. With this apparatus, the coating liquid was centrifuged, and the area of the transmitted light amount was integrated over time and graphed, and the change rate (% / hour) of the transmitted light integrated value per hour was obtained from the slope. The lower the rate of change, the higher the dispersion stability.
The rotation speed of the centrifugation was set to 2,000 rpm, and the temperature was set to 25 ° C. Thereafter, 200 cc of the coating liquid for the protective layer was collected, a circulation test was conducted for 10 hours with a diaphragm pump, the coating liquid was accelerated and deteriorated, and then the dispersion stability of the filler was evaluated again by the above method.
The filler dispersion stability was evaluated from the change in the rate of change of the transmitted light integrated value before and after the circulation test. Specifically, the change in the change rate of the transmitted light integrated value before and after the circulation test is less than 5%, ◎ less than 10%, △ less than 20%, and 20% or more × As an evaluation. These results are shown in Table 3 below.

<Content of tetrahydrofuran and cyclopentanone>
The electrophotographic photoreceptors in Examples 1 to 24 and Comparative Examples 1 to 9 were subjected to heat extraction gas chromatograph mass spectrometry, and the contents of tetrahydrofuran and cyclopentanone were measured. The photoconductor was cut together with the support and sampled so that the solid content of all layers laminated on the support was 0.5 mg to 1.0 mg.
As a measuring device, QP-2010 manufactured by Shimadzu Corporation was used, heat extraction conditions were set at 280 ° C. for 15 minutes, and Py-2020D manufactured by Frontier Laboratories was used as a heating device. As the column, Ultra ALLOY-5 (L = 30 m, ID = 0.25 mm, Film = 0.25 μm) was used, and the column flow rate was 1.0 ml / min. In addition, the ionization method was EI, and the injection mode was split (split ratio 1: 100). Measurement was performed at three points, and the average value was taken. These results are shown in Table 3 below.

<Evaluation of internal curability of protective layer>
The electrophotographic photosensitive members in Examples 1 to 24 and Comparative Examples 1 to 9 were set in the accelerated wear tester shown in FIG. 9, and the amount of wear over time was measured while the photoconductor was forcedly worn constant. The internal curability of the protective layer was evaluated based on the relationship between the applied time and the amount of wear over time.
A lapping film 71 (manufactured by Sumitomo 3M) having a width of 10 cm and a particle size of 3.0 μm was used as the polishing sheet. The amount of wear was determined by measuring the thickness of the electrophotographic photoreceptor 70, and an eddy current film thickness measuring device (manufactured by Fischer Instruments) was used for the thickness measurement.
The evaluation of the internal curability of the protective layer is an approximate curve when the wear amount against the accelerated wear time is plotted from at least 8 points of measured data from the surface of the protective layer to the interface between the protective layer and the charge transport layer. A sample in which a straight line showing a correlation coefficient of 0.996 or more was obtained, and a sample in which a straight line having a correlation coefficient of 0.990 or more and less than 0.996 was obtained, and the correlation coefficient was less than 0.990. The inflection point is clearly observed at △, and the inflection point is clearly observed when the inflection point exceeds half of the thickness of the protective layer, and the correlation coefficient is less than 0.990. The evaluation was performed with a sample in which the inflection point was seen before half of the thickness of the protective layer as x. These results are shown in Table 3 below.

<Adhesive evaluation of protective layer>
The electrophotographic photosensitive members in Examples 1 to 24 and Comparative Examples 1 to 9 were cut into a 10 mm square size, and the surface layer physical property analyzer SAICAS DN-20 type (manufactured by Daipura Wintes Co., Ltd.) was used for the adhesion of the protective layer. Evaluation was performed.
The measurement was performed using a cutting blade having a blade width of 0.5 mm in a constant cutting speed mode with a horizontal cutting speed of 0.1 μm / sec and a vertical cutting speed of 0.01 μm / sec.
Evaluation of adhesiveness was performed as follows.
In other words, the measured horizontal load per cutting time (depth) is almost linear as shown in FIG. 10 when peeling does not occur, but when peeling occurs, as shown in FIG. A drop in horizontal load is observed at the depth at which peeling occurs, and a graph having inflection points is obtained.
Therefore, as for the adhesion of the protective layer, the sample in which a substantially linear graph was obtained up to the depth of the thickness of the protective layer as shown in FIG. 10, and the linear graph was not obtained up to the depth of the thickness of the protective layer, ◯ for samples where no horizontal load drop was observed, △ for samples where a clear drop in horizontal load was observed and the inflection point exceeded half of the thickness of the protective layer, clearly horizontal load Evaluation was performed with x being a sample in which the inflection point was observed before the half of the thickness of the protective layer. These results are shown in Table 3 below.

<Measurement of surface roughness>
With respect to the electrophotographic photosensitive members in Examples 1 to 24 and Comparative Examples 1 to 9, a ten-point average roughness was measured using a surface roughness meter Surfcom 1400D manufactured by Tokyo Seimitsu Co., Ltd., in accordance with JIS B0601 (1994). The thickness Rz and the average interval Sm of the irregularities were measured.
In the measurement, the evaluation length in the longitudinal direction (axial direction) of the photosensitive drum is set to 5.0 mm, and the photosensitive drum is positioned at four points when the circumferential direction is about 90 °. Measurement in the evaluation length was performed.
At this time, measurement at four positions in the circumferential direction of the photosensitive drum is performed by (1) a central position in the longitudinal direction of the photosensitive drum, and (2) the central position and one longitudinal end of the photosensitive drum. And (3) an intermediate position between the central position and the other end in the longitudinal direction of the photosensitive drum. Sm was determined. These results are shown in Table 3 below.

<Potential characteristics of electrophotographic photoreceptor>
The evaluation of the potential characteristics of the electrophotographic photosensitive members in Examples 1 to 24 and Comparative Examples 1 to 9 was performed by comparing the proximity roller charging type charging unit shown in FIG. 4, the cleaning unit using the cleaning blade, and the downstream side of the cleaning unit. It is mounted on a process cartridge equipped with a lubricant coating means for applying zinc stearate to the surface via a brush, and is further applied to an exposure means using a semiconductor laser of 780 nm, and a developing unit is a surface potential meter instead of a developing means. This was carried out by using a modified tandem-type Ricoh digital copier equipped with a developing unit attached with a probe connected to, and a 660 nm LED as a charge eliminating means.
In the evaluation, ten black solid images by full-surface optical writing were output, and the potential of the tenth sheet was read as the exposure portion potential (VL). Thereafter, the developing unit filled with a developing material using a spherical polymer toner was replaced, and an image was output on the electrophotographic photosensitive member, and the obtained image was evaluated.
Further, using the above-mentioned apparatus, a paper run test for 600,000 sheets was performed, and thereafter, the exposure portion potential was measured and the output image was evaluated in the same manner.
As for the image evaluation results, the image defect was not recognized at all, the level at which a good image was obtained was ◎, the image quality was slightly reduced, but the level that was not a problem was ○, the image quality was clearly reduced, The evaluation was made with Δ as the level that was easily judged visually, and x as the level at which image defects were conspicuous and clearly regarded as a problem in image quality. These results are shown in Table 4 below.

  From the above results, the electrophotographic photosensitive member of the present invention has a high dispersion stability of the filler, no problem in the curability inside the protective layer and the adhesion of the protective layer, and high image quality and abrasion resistance can be printed on 600,000 sheets. It was also maintained later, and it became clear that it was excellent in mechanical and electrostatic durability. Further, it was found that by using the charge transport material shown in the present invention, those effects are exhibited more effectively and the electrostatic durability is also improved. Further, it is clear that by setting Rz and Sm on the surface of the protective layer within a predetermined range, it is possible to prevent toner image slipping and streak-like image defects due to poor cleaning, which is effective for further improvement in image quality. became.

  However, when the content of tetrahydrofuran or cyclopentanone is outside the range of the present invention, the dispersion stability of the filler tends to decrease, and the internal curability and adhesiveness of the protective layer tend to decrease. It was. As a result, even though initially good, a significant increase in exposed area potential was observed after printing 600,000 sheets, wear resistance was reduced, or uneven wear was observed. A decrease was observed.

  From the above results, the electrophotographic photosensitive member of the present invention increases the dispersion stability of the filler, the degree of cure inside the protective layer is uniform, and the adhesiveness is good. In addition, it is possible to provide an electrophotographic photosensitive member having excellent scratch resistance, high stability of the exposed portion potential, and excellent mechanical and electrostatic durability. Further, by using the photoreceptor, it is possible to provide an image forming apparatus that has little image density fluctuation even when used repeatedly for a long period of time, has few image quality defects, and is excellent in image quality stability.

  The image forming apparatus and process cartridge using the electrophotographic photosensitive member of the present invention can be widely applied to a copying machine, a facsimile, a laser printer, a direct digital plate making machine, and the like.

1C, 1M, 1Y, 1K Photoconductor 2C, 2M, 2Y, 2K Charging member 3C, 3M, 3Y, 3K Laser light 4C, 4M, 4Y, 4K Developing member 5C, 5M, 5Y, 5K Cleaning member 6C, 6M, 6Y , 6K Image forming element 7 Transfer paper (recording paper)
DESCRIPTION OF SYMBOLS 8 Paper feeding roller 9 Registration roller 10 Transfer conveyance belt 11C, 11M, 11Y, 11K Transfer brush 12 Fixing device 21 Electrophotographic photosensitive member 22 Static elimination lamp 23 Charge charger 24 Image exposure part 25 Developing unit 26 Pre-transfer charger 27 Registration roller 28 Transfer Paper 29 Transfer charger 30 Separation charger 31 Separation claw 32 Charger before cleaning 33 Fur brush 34 Blade 51 Gap tape (gap forming member)
52 Metal shaft 53 Image forming area 54 Non-image forming area 55, 70 Electrophotographic photoreceptor 56 Charging roller 71 Lapping film 101 Drum 102 Contact charging device 103 Image exposure 104 Developing device 105 Transfer body 106 Contact transfer device 107 Cleaning unit 301 Light source 301a Emitting point 302 Collimating lens 303 Cylindrical lens 304 Aperture 305 Rotating polygon mirror (polygon mirror)
306a Scanning lens 1
306b Scanning lens 2
307a Reflector 1
307b Reflector 2
307c Reflector 3
308 Photosensitive member surface 309 Scanning direction

JP 56-48637 A JP-A 64-1728 JP-A-4-281461 Japanese Patent No. 2821318 JP 2000-330313 A JP 2005-99688 A JP 2006-330086 A Japanese Patent No. 3802787 Japanese Patent Laid-Open No. 2007-72487 Japanese Patent Laid-Open No. 7-5703 Japanese Patent No. 4145570

Claims (21)

A support, a charge generation layer, a charge transport layer containing a charge transport material and a binder resin, a filler, a polycarboxylic acid compound, and a polymerizable compound having a charge transport structure and a charge on the support, A protective layer containing a curable resin containing a polymerizable compound having no transportable structure is laminated in this order,
The electrophotographic photoreceptor, wherein the content of all layers laminated on the support relative to the solid content is from 50 ppm to 10,000 ppm for tetrahydrofuran and from 1 ppm to 100 ppm for cyclopentanone.   2. The electrophotographic photosensitive member according to claim 1, wherein the content of tetrahydrofuran with respect to the solid content of all layers laminated on the support is 200 ppm or more and 3,000 ppm or less.   The electrophotographic photosensitive member according to claim 1, wherein the content of cyclopentanone relative to the solid content of all the layers laminated on the support is 2 ppm or more and 30 ppm or less.   The electrophotographic photosensitive member according to claim 1, wherein tetrahydrofuran is contained in the charge transport layer and the protective layer, and cyclopentanone is contained in the protective layer.   The electrophotographic photosensitive member according to claim 1, wherein the charge transport material has a molecular weight of 600 or more and 900 or less. The electrophotographic photosensitive member according to claim 1, wherein the charge transport material is a distyryl compound represented by the following general formula (1).
However, in said formula (1), R < ₁ > -R < ₄ > represents either a hydrogen atom, a C1-C4 alkyl group, a C1-C4 alkoxy group, and a phenyl group, respectively, respectively. But it can be different. The phenyl group may be unsubstituted or substituted with any substituent of an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms.
A represents any of an arylene group which may have a substituent and a group represented by the following general formula (1a).
However, in said formula (1a), R < ₅ >, R < ₆ > and R < ₇ > represent either a hydrogen atom, a C1-C4 alkyl group, a C1-C4 alkoxy group, and a phenyl group, respectively. . The phenyl group may be unsubstituted or substituted with any substituent of an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms.
B and B ′ each represent an aryl group which may have a substituent and a group represented by the following general formula (1b). B and B ′ may be the same or different.
However, in said formula (1b), Ar < ₁ > represents the arylene group which may have either a C1-C4 alkyl group and an alkoxy group as a substituent, and Ar < ₂ > and Ar < ₃ > are , Each represents an aryl group optionally having any one of an alkyl group having 1 to 4 carbon atoms and an alkoxy group as a substituent. The electrophotographic photosensitive member according to claim 6, wherein the charge transport material is a distyryl compound represented by the following general formula (2).
However, in said formula (2), R < ₈ > -R < ₃₃ > is a phenyl group which may have a hydrogen atom, a C1-C4 alkyl group, a C1-C4 alkoxy group, and a substituent, respectively. Each of which may be the same or different. The electrophotographic photosensitive member according to claim 6, wherein the charge transport material is a distyryl compound represented by the following general formula (3).
However, in said formula (3), R < ₃₄ > -R < ₅₇ > is a phenyl group which may have a hydrogen atom, a C1-C4 alkyl group, a C1-C4 alkoxy group, and a substituent, respectively. Each of which may be the same or different.   The electrophotographic photosensitive member according to claim 1, wherein the charge transporting structure of the polymerizable compound having a charge transporting structure is a triarylamine structure.   10. The polymerizable compound having a charge transporting structure and the polymerizable compound not having a charge transporting structure each have an acryloyloxy group and / or a methacryloyloxy group as a functional group. Electrophotographic photoreceptor.   The polymerizable compound having no charge transporting structure has three or more polymerizable functional groups, and the polymerizable compound having a charge transporting structure has one polymerizable functional group. The electrophotographic photosensitive member described.   The electrophotographic photosensitive member according to claim 1, wherein the filler is metal oxide particles.   The electrophotographic photosensitive member according to claim 12, wherein the metal oxide particles are α-alumina particles.   The electrophotographic photosensitive member according to claim 1, wherein the filler has an average primary particle size of 0.05 μm or more and less than 0.7 μm.   The electrophotographic photosensitive member according to claim 1, wherein the protective layer has a thickness of 1 μm to 5 μm.   The electrophotographic photosensitive member according to claim 1, wherein the ten-point average roughness Rz on the surface of the protective layer is 0.3 μm or more and 1.0 μm or less.   The electrophotographic photosensitive member according to any one of claims 1 to 16, wherein an average interval Sm of unevenness existing on the surface of the protective layer is 0.3 mm or more and 1.0 mm or less.   18. At least the electrophotographic photosensitive member according to any one of claims 1 to 17, charging means for charging the electrophotographic photosensitive member, exposure means for forming an electrostatic latent image on the electrophotographic photosensitive member, An image forming apparatus comprising: a developing unit that develops an electrostatic latent image with toner; and a transfer unit that transfers the developed toner image to a recording medium.   19. The image forming apparatus according to claim 18, wherein the image forming apparatus is a tandem type in which a plurality of image forming elements each including at least an electrophotographic photosensitive member, a charging unit, an exposure unit, a developing unit, and a transfer unit are arranged.   The image forming apparatus according to any one of claims 18 to 19, further comprising a lubricating substance applying unit that applies a lubricating substance to the surface of the electrophotographic photosensitive member.   The electrophotographic photosensitive member according to any one of claims 1 to 17, and at least one means selected from a charging means, an exposure means, a developing means, a transfer means, a cleaning means, and a static elimination means, are integrated. A process cartridge which is detachable from an image forming apparatus main body.