JP2010271434A - Manufacturing method for electrophotographic photoreceptor, the electrophotographic photoreceptor, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for an electrophotographic photoreceptor for preventing the occurrence of unevenness in image density in one page due to unevenness in VL in a photoreceptor 1 body, improving wear resistance of the electrophotographic photoreceptor, achieving its high durability, and enhancing a quality of image, and also to provide the electrophotographic photoreceptor manufactured by this method. <P>SOLUTION: In this manufacturing method for the electrophotographic photoreceptor constituted by laminating at least a charge generating layer and a charge transport layer on an electroconductive support body in this order, the charge transport layer is coated by a dip coating method satisfying a following expression (1): (1) (A-B)/C<1 (wherein, A denotes the time when a lower end in a scope of effective writing of the photoreceptor is immersed in a coating liquid, B denotes the time when an upper end in the scope of effective writing of the photoreceptor is immersed in the coating liquid, and C denotes the time when the center in the scope of effective writing of the photoreceptor is immersed in the coating liquid). Preferably, a cross linking charge transport layer is laminated on the charge transport layer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an electrophotographic photosensitive member, an electrophotographic photosensitive member manufactured using the method, and an image forming apparatus equipped with the photosensitive member.

  2. Description of the Related Art In recent years, image forming apparatuses such as electrophotographic laser printers and digital copying machines have improved image quality and stability, and their speed, size, and full color are rapidly increasing. More recently, these image forming apparatuses have been used for commercial printing, and the importance of improving the image quality at the same time as improving the durability of the electrophotographic photosensitive member used for them has further increased.

As electrophotographic photoreceptors used in these image forming apparatuses, those using organic photosensitive materials are widely used for reasons such as cost, productivity and environmental stability. The layer structure of these electrophotographic photoreceptors is a single layer type having a charge generation function and a charge transport function in one layer, and functions as a charge generation layer having a charge generation function and a charge transport layer having a charge transport function. The latter is widely used from the viewpoints of stability of electrostatic characteristics and durability.
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. To generate a charge (charge pair). The charges generated thereby are injected into the charge transport layer at the interface between the charge generation layer and the charge transport layer, and further moved through the charge transport layer by an electric field, reach the surface of the photoreceptor, and the surface charge given by the charge becomes medium. Summing to form an electrostatic latent image.

  However, it has been recognized as a problem that organic photoreceptors are more likely to be worn by repeated use than inorganic photoreceptors. As wear of the photosensitive layer on the surface progresses, the charged potential of the photoconductor decreases and the photosensitivity deteriorates, which promotes deterioration in image quality such as increased background contamination and decreased image density. High body durability is strongly desired. Furthermore, there is an increasing need for downsizing of image forming apparatuses and downsizing of photosensitive members in recent years. As the diameter of photoconductors has decreased, the demand for higher durability of photoconductors has become even higher, and higher durability of photoconductors using organic materials is a more important issue to be solved sooner. It is recognized as.

  As a method for realizing high durability of the photoconductor, a protective layer is provided on the outermost surface of the photoconductor, and fillers and fine particles are dispersed in the protective layer, the protective layer is cured, and surface lubricity is increased. How to do is widely known. By these methods, it has been confirmed that the abrasion resistance of the surface of the photoconductor is improved, the occurrence of scumming with repeated use can be suppressed, and the durability of the photoconductor is improved.

  On the other hand, however, there is a problem that non-uniformity in image density occurs within one page by laminating a protective layer. Image density unevenness is largely related to variations in the post-exposure potential (VL) in one photoconductor. The variation in VL is influenced by the deviation of the film thickness, the dispersion uniformity of molecules in the film, and the interface state of each layer. As the number of layers constituting the photoreceptor increases, the dispersion of the molecules becomes more uniform. The effect of property and interface state is increased. Laminating the protective layer increases the layer interface in the photoreceptor, and is one of the factors that increase VL variation. Furthermore, while the protective layer improves wear resistance, not only does the charge mobility inferior to that of the charge transport layer, but also electron trap sites are easily formed in the film, and the VL variation inevitably increases. Resulting in. As a result, image density unevenness in one page occurs, and it is necessary to reduce variation in VL in one photoconductor in a photoconductor having a protective layer laminated thereon. Variation in VL in one photoconductor can be broadly divided into two types: variation in the longitudinal direction of the photoconductor and variation in the circumferential direction. In particular, variation in VL in the longitudinal direction is larger than that in the circumferential direction. Since image density unevenness tends to be noticeable in the longitudinal direction of the photoconductor, it is necessary to reduce variations in VL in the longitudinal direction.

As a factor that causes VL variation, the coating film non-uniformity such as coating unevenness generated in the manufacturing process of the photoreceptor is particularly large. Therefore, the following methods have been proposed for the purpose of improving the non-uniformity of the coating film.
(1) In Patent Document 1 (Japanese Patent Laid-Open No. 11-258838), when the charge generation layer is laminated by dip coating, the entire drum is immersed in the coating liquid and the immersion speed of the drum in the coating liquid. A method of preventing streaky coating unevenness by controlling the relationship with the stationary time in a state has been proposed.
Although this method can prevent streaky coating unevenness when the charge generation layer is dip coated, it cannot improve the coating uniformity during dip coating of the charge transport layer.

(2) In Patent Document 2 (Japanese Patent Application Laid-Open No. 2008-062131), in the dip coating method, with respect to the upper portion of the drum, the pulling speed is decreased in accordance with an exponential function with an increase in the drum pulling distance. In the pulling process of the lower part excluding the upper end part, a method is proposed in which the film thickness is made uniform over the entire length of the drum by keeping the drum pulling speed constant.
(3) In Patent Document 3 (Japanese Patent Application Laid-Open No. 2000-321796), when the object to be coated is immersed in the coating liquid in the coating tank, the lower end of the object to be coated is applied to the coating liquid in the coating tank. After intrusion, by moving the surface of the coated object and the coating tank or immersing it while changing the relative speed between the coating liquid that is stationary in the coating tank, A coating method in which coating film defects such as color unevenness and coating unevenness do not occur is proposed.
(4) In Patent Document 4 (Japanese Patent Laid-Open No. 09-258461), in the method for producing a laminated electrophotographic photosensitive member, the moving speed of the substrate after coating of the photosensitive layer is higher than the moving speed of the substrate during coating of the photosensitive layer. There has been proposed a method that enables uniform film formation by producing a multilayer electrophotographic photosensitive member at a high speed.
All of these methods have been proposed in order to make the coating thickness uniform. However, just making the coating thickness uniform does not reduce the variation in VL. It is insufficient as a method.

(5) Patent Document 5 (Japanese Patent Laid-Open No. 2008-46167) discloses a charge generation layer mainly composed of a charge generation material, a charge transportation material and a charge mainly composed of a binder resin on a conductive support. At least a transport layer, and a protective layer formed by curing reaction of a radical polymerizable compound having no charge transport structure and a radical polymerizable compound having a charge transport structure, the charge generation layer, the charge A method for producing an electrophotographic photosensitive member in which a transport layer and a protective layer are laminated in this order on the conductive support, and after forming the charge transport layer, polishing the surface of the charge transport layer, By forming the protective layer on the surface of the polished charge transport layer, the increase in residual potential is suppressed by eliminating the concentration gradient of the charge transport material generated on the surface of the charge transport layer and stable output of high-quality images. how to It is proposed.
This method is effective against the increase in residual potential and VL variation, but requires a new process of polishing the surface of the charge transport layer. In order to uniformly polish the entire surface of the charge transport layer, high accuracy is required. A polishing mechanism must be provided, which increases the manufacturing cost.

An object of the present invention is to solve the conventional problems and achieve the following objects.
That is, the present invention can suppress uneven image density in one page caused by VL variation in one photoconductor, further improve the wear resistance of the electrophotographic photoconductor, and achieve high durability and high image quality. It is an object of the present invention to provide a method for producing an electrophotographic photoreceptor capable of realizing the above and an electrophotographic photoreceptor produced by the method. Another object of the present invention is to provide an image forming apparatus provided with the photoreceptor.

（式（４）中、ｎは０又は１であり、Ａｒ₃及びＡｒ₄は、置換もしくは無置換のアリール基、又は置換もしくは無置換の複素環基を表わし、Ｒ₆〜Ｒ₈は、それぞれ独立して、水素原子、置換もしくは無置換のアルキル基、置換もしくは無置換のアルコキシ基、置換もしくは無置換のアリール基、置換もしくは無置換のアリールオキシ基、又は置換もしくは無置換の複素環基を表わし、Ｒ₇、Ｒ₈は、互いに結合して環を形成してもよく、Ａｒ₅は、置換もしくは無置換のアリーレン基を表わす。）
（４）前記電荷輸送層に含有される電荷輸送物質が、下記一般式（５）で示されるジスチリルベンゼン化合物を含有することを特徴とする前記（１）又は（２）に記載の電子写真感光体の製造方法。

（上記一般式（５）中、Ａｒ₇は置換又は無置換の芳香族炭化水素基を表わす。Ａ₁、Ａ₂は下記一般式（６）で表わされ、同一でも異なっていてもよい。）

（上記一般式（６）中、Ａｒ₈、Ａｒ₉、Ａｒ₁₀は置換又は無置換の芳香族炭化水素基を表わす。また、Ａｒ₈とＡｒ₉、Ａｒ₉とＡｒ₁₀、Ａｒ₁₀とＡｒ₈は結合して複素環を形成してもよい。）
（５）前記架橋型電荷輸送層が、少なくとも電荷輸送性構造を有しない３官能以上のラジカル重合性モノマーと１官能の電荷輸送性構造を有するラジカル重合性化合物を反応硬化することにより形成されたものであることを特徴とする前記（２）ないし（４）のいずれかに記載の電子写真感光体の製造方法。
（６）前記ラジカル重合性モノマーの官能基が、アクリロイルオキシ基、及びメタクリロイルオキシ基より選ばれる少なくとも１種の官能基であることを特徴とする前記（５）に記載の電子写真感光体。
（７）前記ラジカル重合性化合物の官能基が、アクリロイルオキシ基又はメタクリロイルオキシ基であることを特徴とする前記（５）又は（６）に記載の電子写真感光体の製造方法。
（８）前記架橋型電荷輸送層の反応硬化は、加熱手段又は光エネルギー照射手段を用いて行われることを特徴とする前記（５）乃至（７）のいずれかに記載の電子写真感光体の製造方法。
（９）前記（１）ないし（８）のいずれかに記載の電子写真感光体の製造方法により製造されたことを特徴とする電子写真感光体。
（１０）前記（９）に記載の電子写真感光体を備えたことを特徴とする画像形成装置。
（１１）前記画像形成装置が、少なくとも複数の電子写真感光体、帯電手段、画像露光手段、現像手段およびクリーニング手段からなる複数の画像形成部を有するタンデム方式のフルカラー画像形成装置であることを特徴とする前記（１０）に記載の画像形成装置。 The above problems are solved by the present invention described below.
(1) In a method for producing an electrophotographic photosensitive member in which at least a charge generation layer and a charge transport layer are laminated in this order on a conductive support, the charge transport layer satisfies the formula (1) by dip coating. A method for producing an electrophotographic photoreceptor, which is coated.
Formula (1)
(AB) / C <1
(Here, A is the time during which the lower end of the effective writing range of the photosensitive member is immersed in the coating liquid, B is the time during which the upper end of the effective writing range of the photosensitive member is immersed in the coating solution, and C is the photosensitive member. The time during which the center of the effective writing range is immersed in the coating solution.)
(2) The method for producing an electrophotographic photosensitive member according to (1), wherein a cross-linked charge transport layer is laminated on the charge transport layer, and the film thickness thereof is 1 μm or more and 10 μm or less.
(3) The electrophotographic photoreceptor according to (1) or (2) above, wherein the charge transport material contained in the charge transport layer contains a compound represented by the following general formula (4): Production method.

(In the formula (4), n is 0 or 1, Ar ₃ and Ar ₄ represent a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, and R _{6 to} R ₈ are each represented by Independently, a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted heterocyclic group R ₇ and R ₈ may combine with each other to form a ring, and Ar ₅ represents a substituted or unsubstituted arylene group.)
(4) The electrophotography as described in (1) or (2) above, wherein the charge transport material contained in the charge transport layer contains a distyrylbenzene compound represented by the following general formula (5): A method for producing a photoreceptor.

(In the general formula (5), Ar ₇ represents a substituted or unsubstituted aromatic hydrocarbon group. A ₁ and A ₂ are represented by the following general formula (6), which may be the same or different. )

(In the above general formula (6), Ar ₈ , Ar ₉ and Ar ₁₀ represent a substituted or unsubstituted aromatic hydrocarbon group. Ar ₈ and Ar ₉ , Ar ₉ and Ar ₁₀ , Ar ₁₀ and Ar ₈ May combine to form a heterocyclic ring.)
(5) The crosslinkable charge transport layer is formed by reactive curing of at least a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. The method for producing an electrophotographic photosensitive member according to any one of (2) to (4) above, wherein
(6) The electrophotographic photosensitive member according to (5), wherein the functional group of the radical polymerizable monomer is at least one functional group selected from an acryloyloxy group and a methacryloyloxy group.
(7) The method for producing an electrophotographic photosensitive member according to (5) or (6) above, wherein the functional group of the radical polymerizable compound is an acryloyloxy group or a methacryloyloxy group.
(8) The electrophotographic photosensitive member according to any one of (5) to (7), wherein the reaction-curing of the crosslinkable charge transport layer is performed using a heating unit or a light energy irradiation unit. Production method.
(9) An electrophotographic photosensitive member produced by the method for producing an electrophotographic photosensitive member according to any one of (1) to (8).
(10) An image forming apparatus comprising the electrophotographic photosensitive member according to (9).
(11) The image forming apparatus is a tandem-type full-color image forming apparatus having a plurality of image forming units each including at least a plurality of electrophotographic photosensitive members, a charging unit, an image exposing unit, a developing unit, and a cleaning unit. The image forming apparatus according to (10).

  According to the method for producing an electrophotographic photoreceptor of the present invention, when forming a photoreceptor having a charge generation layer and a charge transport layer sequentially provided on a conductive support, the charge transport layer conforms to the above formula (1). By coating under different coating conditions, image density unevenness caused by non-uniformity of the interface state between the charge generation layer and the charge transport layer is suppressed, and a cross-linked charge transport layer is provided on the charge transport layer. An electrophotographic photosensitive member is provided that has improved wear resistance and can achieve high durability and high image quality.

1 is a schematic diagram illustrating an example of an image forming apparatus of the present invention. 1 is an example of a cross-sectional view of an electrophotographic photosensitive member of the present invention. It is explanatory drawing of the calculation method of Formula (1).

Hereinafter, a method for producing an electrophotographic photoreceptor of the present invention and an image forming apparatus using the photoreceptor will be described in detail with reference to the drawings.
The present inventors have proposed that the charge transport layer formed under the crosslinkable charge transport layer, not the crosslinkable charge transport layer, has the side effect of uneven image density in one page due to the formation of the crosslinkable charge transport layer as the protective layer. As a result, it has been found that the improvement can be greatly improved, and the present invention has been completed. Therefore, according to the present invention, there is provided an image forming apparatus capable of achieving both high image quality and high durability, and stably obtaining a high-quality image without image density unevenness within one page.

  The present invention relates to a charge generation layer mainly comprising a charge transport material on a conductive support, a charge transport layer mainly comprising a charge transport material and a binder resin, and a radical preferably having no charge transport structure. A method for producing a photoreceptor in which a polymerizable compound and a crosslinkable charge transport layer formed by subjecting a radical polymerizable compound having a charge transport structure to a curing reaction are sequentially laminated, wherein the charge transport layer is applied. The method includes a method for producing a photoreceptor, wherein a cross-linkable charge transport layer is formed after coating under conditions such that the formula (1) is satisfied.

  The charge generation layer and the charge transport layer are laminated by a general coating method such as a dip coating method. When the charge transport layer is laminated by dip coating, an organic solvent is generally used as a solvent for the coating solution. It is used. It is well known that the resin used in the lower charge generation layer is soluble in this organic solvent. When the charge transport layer is laminated on the charge generation layer by dip coating, the resin on the very surface of the charge generation layer is slightly dissolved by the organic solvent of the coating solution, and only occurs on the very surface of the charge generation layer. It is considered that the dissolution of the resin in the resin affects the variation in VL in one photoconductor, and further affects the image density unevenness in one page.

  The charge generation layer forms a layer with the charge generation material dispersed in the resin. Since the charge generation material is covered with resin, when the charge generation layer is dip coated, the surface is covered with resin. The resin near the surface of the charge generation layer is slightly dissolved by the solvent of the coating solution when the charge transport layer is laminated. When a large amount of resin is dissolved, the concentration of the charge generation material becomes relatively high, and the intermolecular distance between the charge generation material and the charge transport material in the charge transport layer is closer, so the charge transfer at the interface is thought to be smooth. .

  In a general dip coating method, the conductive support is inserted perpendicularly to the coating liquid from the lower end in the axial direction, and the entire coating area of the conductive support is immersed in the coating liquid, that is, And it stops for a predetermined time in the state immersed in the coating liquid to the upper end of the electroconductive support body. Thereafter, the conductive support is pulled up while controlling the pulling rate to laminate a layer having a predetermined film thickness, so that the lower end and the upper end of the coating region of the conductive support are immersed in the coating liquid. However, the lower part has a longer immersion time and the upper part has a shorter immersion time. In other words, when the charge transport layer is dip coated on the charge generation layer, the resin at the charge generation layer dissolves much at the lower end near the interface between the charge generation layer and the charge transport layer, and the upper end is immersed. The amount of dissolution is small due to the short time. As a result, a concentration gradient of the charge generating substance in the vicinity of the interface occurs from the lower end to the upper end of the support. In general, it is known that the concentration of the charge generating material in the charge transport layer greatly affects VL. From this, it is considered that the concentration gradient of the charge generation material formed in the vicinity of the interface due to the difference in the dissolution of the resin causes the VL variation in the axial direction of the photoreceptor.

  On the other hand, the present inventors considered that VL variation would be eliminated if the concentration gradient in the axial direction was reduced in the effective writing range of the support. In the case of dip coating, various methods such as changing the insertion speed and pulling speed, and lifting the support by a certain length and then inserting it again into the coating solution, then lifting and coating. There is a method, but in either case, the concentration gradient in the axial direction can be reduced if the difference in the immersion time between the upper end and the lower end of the effective writing range of the photosensitive member becomes small. Therefore, as a result of extensive studies, the difference between the time during which the lower end of the effective writing range of the photoreceptor is immersed in the coating liquid and the time during which the upper end of the effective writing range of the photoreceptor is immersed in the coating liquid is It has been found that the concentration gradient caused by the application of the charge transport layer can be eliminated by coating the center of the effective writing range of the photosensitive member under a condition that is smaller than the time of immersing in the coating solution. The upper end of the effective writing range of the photoconductor is the position of the edge of the maximum printed material that can be passed through the upper side of the support during dip coating, and the lower end of the effective writing range of the photoconductor is during dip coating It is the position of the edge of the largest printed matter that can be passed through the underside of the support. The center of the effective writing range of the photoconductor is a position that is equidistant from both ends of the maximum printed material that can be passed with respect to the axial direction of the photoconductor.

That is, by applying the coating material under the condition satisfying the formula (1), it is possible to eliminate the variation in VL due to the difference in immersion time.
Formula (1)
(AB) / C <1
(Here, A is the time during which the lower end of the effective writing range of the photosensitive member is immersed in the coating liquid, B is the time during which the upper end of the effective writing range of the photosensitive member is immersed in the coating liquid, and C is the photosensitive member. The time during which the center of the effective writing range is immersed in the coating solution.)

Further, (A−B) / C in the formula (1) is preferably in the range of 0.3 <(A−B) / C <0.7. With respect to A, B, and C, 140 seconds < It is preferable that A <270 seconds, 70 seconds <B <200 seconds, and 100 seconds <C <230 seconds.
In the present invention, the above formula (1) may be satisfied, but the tact (manufacturing time required for one coating) surface during production and the charge transport layer coating solution by dissolution of the charge generation layer solution Considering contamination, 0.3 <(A−B) / C <0.7 is preferable. Basically, it is necessary to lengthen the dipping stop time when trying to reduce (A-B) / C, and then it takes time to apply one (one set if several units are applied). Will reduce productivity. On the other hand, if it is 0.3 or less, the immersion stop time is lengthened, so that the charge generation layer solution dissolves in the charge transport layer solution, and there is a concern that the charge transport layer solution is contaminated. Also, by setting it to less than 0.7, the VL variation can be further reduced.
As a result, the concentration gradient of the charge generation material generated in the effective writing range of the support can be minimized at the interface between the charge generation layer and the charge transport layer of the support. Then, variations in VL due to the lamination of the crosslinkable charge transport layer on the charge transport layer can be eliminated, and uneven image density in one page can be eliminated.

  According to the present invention, a cross-linked charge transport layer effective for improving wear resistance and scratch resistance is formed on the outermost surface, and the coating conditions of the charge transport layer formed thereunder are expressed by the formula (1). By controlling so as to satisfy the above, variation in VL, which was a problem when using a cross-linked charge transport layer, was suppressed, and it was possible to achieve both high durability and high image quality.

<Image forming apparatus>
First, FIG. 1 is a partial cross-sectional schematic diagram showing an example of an image forming apparatus to which the present invention can be applied.
The image forming apparatus of the present invention uses a laminated photoreceptor having on its surface a cross-linked charge transport layer having very high wear resistance and scratch resistance. Further, in the image forming apparatus of the present invention, an electrophotographic photosensitive member, at least a charging unit, an exposing unit, a developing unit, a transfer unit that transfers a visible image on the photosensitive member directly or via an intermediate transfer member, and a cleaning unit. Means, a lubricant application means, and a static elimination means. As such an image forming method of the present invention, at least after the process of negative charging, image exposure, and development on the photoreceptor, transfer of the toner image to the transfer body, fixing, cleaning of the surface of the photoreceptor, application of a lubricant, A process of static elimination can be executed. In addition, an image forming method in which an electrostatic latent image is directly transferred to a transfer member and developed does not necessarily have the above process.

As the charging means, a charging charger (3) is preferably used as means for uniformly charging the photosensitive member. As the charging means, a corotron device, a scorotron device, a solid discharge element, a needle electrode device, a roller charging device, a conductive brush device, or the like is used, and a known system can be used.
As the exposure means, an image exposure unit (5) for forming an electrostatic latent image on the uniformly charged photoreceptor (1) is used. As the light source, all luminescent materials such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL) can be used. Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.

As the developing means, a developing unit (6) for visualizing the electrostatic latent image formed on the photoreceptor (1) is used. Development methods include a one-component development method using a dry toner, a two-component development method, and a wet development method using a wet toner. When the photosensitive member is negatively charged and image exposure is performed, a negative electrostatic latent image is formed on the surface of the photosensitive member. A positive image can be obtained by developing the toner with positive polarity toner (detection fine particles), and a negative image can be obtained by developing the toner with negative polarity toner.
As the transfer means, a transfer charger (10) for transferring the toner image visualized on the photoreceptor onto the transfer body (9) is used. In addition, a pre-transfer charger (7) may be used for better transfer. As these transfer means, a transfer charger, an electrostatic transfer method using a bias roller, a mechanical transfer method such as an adhesive transfer method and a pressure transfer method, and a magnetic transfer method can be used. As the electrostatic transfer method, the charging means can be used.

  As the cleaning means, a fur brush (14) and a cleaning blade (15) for cleaning the toner remaining on the photoreceptor after transfer are used. Further, a pre-cleaning charger (13) may be used in order to perform cleaning more efficiently. Other cleaning means include a web method, a magnet brush method, and the like, but each may be used alone or in combination.

Lubricant applying means Lubricant applying means is known as a method for reducing the coefficient of friction on the surface of the photoreceptor in order to perform cleaning efficiently. Further, the lubricant is also known as an effect as a protective film that reduces deterioration due to discharge energy during charging. For these reasons, the application of the lubricant is very effective for improving the durability of the photoreceptor.
The lubricant application means includes a lubricant (rod-like body) (16), a roller (17) for scraping the lubricant 16 and applying it to the photoreceptor, and an application blade (18) for uniformly applying the lubricant. Yes.

As the lubricant applied to the photoreceptor, a known lubricant molded into a solid can be used. Examples thereof include, but are not limited to, the following or metal salts of the following compounds. These can be used alone or in combination of two or more.
Inorganic lubricants such as mica, boron nitride, molybdenum disulfide, tungsten disulfide, kaolin, montmorillonite, calcium fluoride, graphite; hydrocarbon compounds such as liquid paraffin, paraffin wax, microwax, low-polymerized polyethylene; lauric acid, Fatty acid compounds such as myristic acid, palmitic acid, stearic acid, arachidic acid, and behenic acid; fatty acid amide compounds such as stearylamide, palmitylamide, oleinamide, methylenebisstearamide, ethylenebisstearamide; Ester compounds such as lower alcohol esters, polyhydric alcohol esters of fatty acids, fatty acid polyglycols; alcohols such as cetyl alcohol, stearyl alcohol, ethylene glycol, polyethylene glycol, poly-rolled cerol Call compounds; carnauba wax, Karuderirarou, beeswax, spermaceti, insect wax, natural waxes such as montan wax; Other silicone compounds, fluorine compounds, and the like.

  Among these, it is preferable to use a metal soap. The metal soap is a non-alkali metal salt of an organic acid such as the fatty acid described above, and is generally commercially available, for example, aluminum stearate, calcium stearate, calcium oleate, zinc stearate, zinc laurate, olein Zinc acid, magnesium stearate, nickel stearate, cobalt stearate, barium stearate and the like can be used. In particular, a metal soap containing zinc as a metal is particularly preferable because it has a particularly low charge storage property during repeated use.

In the image forming apparatus of the present invention, a neutralizing unit can be used for the purpose of removing the latent image on the photosensitive member.
As the charge removal means, a charge removal lamp (2) and a charge removal charger are used, and the exposure light source and the charging means can be used respectively.

  In the image forming apparatus of the present invention, means for separating the transfer member (9) from the photosensitive member (1) can be used in addition to the above-described means. As means for separating the transfer member (9) from the photosensitive member (1), a separation charger (11) and a separation claw (12) are used. As other separation means, electrostatic adsorption induction separation, side end belt separation, tip grip conveyance, curvature separation, and the like are used. As the separation charger (11), the charging means can be used.

Next, the photoreceptor used in the image forming apparatus of the present invention will be described according to its layer structure.
<Layer structure of electrophotographic photoreceptor>
The electrophotographic photosensitive member used in the present invention will be described with reference to the drawings.
FIG. 2 is a cross-sectional view showing the electrophotographic photosensitive member of the present invention.
Laminated structure in which a charge generation layer (35) having a charge generation function, a charge transport layer (37) having a charge transport function, and a cross-linked charge transport layer (39) are stacked on a conductive support (31) This is a photoreceptor.

<Conductive support>
Examples of the conductive support (31) include those having a volume resistance of 10 ¹⁰ Ω · cm or less, for example, metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, oxidation Metal oxide such as indium is deposited or sputtered to form film or cylindrical plastic, paper coated, or aluminum, aluminum alloy, nickel, stainless steel, etc. After conversion, a tube that has been subjected to surface treatment such as cutting, superfinishing, or polishing can be used. Further, an endless nickel belt and an endless stainless steel belt disclosed in Japanese Patent Application Laid-Open No. 52-36016 can be used as the conductive support (31).

In addition, the conductive support dispersed in a suitable binder resin and coated on the support can also be used as the conductive support (31) of the present invention.
Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc and silver, or metal oxide powder such as conductive tin oxide and ITO. Can be mentioned. The binder resin used at the same time is polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. , Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, Examples thereof include thermoplastic, thermosetting resins, and photocurable resins such as melamine resin, urethane resin, phenol resin, and alkyd resin. Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.

  Further, a heat shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, polytetrafluoroethylene-based fluororesin on a suitable cylindrical substrate. Those provided with a conductive layer can be used favorably as the conductive support (31) of the present invention.

<Photosensitive layer>
(Charge generation layer)
The charge generation layer (35) is a layer mainly composed of a charge generation material having a charge generation function, and is formed by applying and drying a coating solution in which the charge generation material and the binder resin are dissolved or dispersed in a solvent. Is done. As the charge generation material, inorganic materials and organic materials can be used.
Inorganic materials include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compounds, and amorphous silicon. In amorphous silicon, dangling bonds that are terminated with hydrogen atoms or halogen atoms, or those that are doped with boron atoms, phosphorus atoms, or the like are preferably used.

  On the other hand, a known material can be used as the organic material. For example, phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, azulenium salt pigments, squaric acid methine pigments, azo pigments having a carbazole skeleton, azo pigments having a triphenylamine skeleton, azo pigments having a diphenylamine skeleton, dibenzothiophene skeleton Azo pigments having fluorenone skeleton, azo pigments having oxadiazole skeleton, azo pigments having bis-stilbene skeleton, azo pigments having distyryl oxadiazole skeleton, azo pigments having distyrylcarbazole skeleton, perylene Pigments, anthraquinone or polycyclic quinone pigments, quinoneimine pigments, diphenylmethane and triphenylmethane pigments, benzoquinone and naphthoquinone pigments, cyanine and azomethine pigments, Goido based pigments, and bisbenzimidazole pigments. These charge generation materials can be used alone or as a mixture of two or more.

The binder resin used as necessary for the charge generation layer (35) includes polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly- N-vinyl carbazole, polyacrylamide, polyvinyl benzal, polyester, phenoquinone resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone Etc. These binder resins can be used alone or as a mixture of two or more.
The addition amount of the binder resin is usually 0 to 500 parts by weight, preferably 10 to 300 parts by weight with respect to 100 parts by weight of the charge generation material.

The charge generation layer is formed by applying a coating liquid in which a charge generation material is dispersed in a solvent using a known dispersion method such as a ball mill, an attritor, a sand mill, and an ultrasonic wave together with a binder resin as necessary. It is formed by applying and drying on the upper or undercoat layer. The binder resin may be added before or after the charge generating material is dispersed.
As the solvent used here, isopropanol, acetone, methyl ethyl ketone, cyclohexane, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin and the like are generally used. Among them, it is preferable to use ketone solvents, ester solvents, and ether solvents. These may be used alone or in combination of two or more.

The coating solution for the charge generation layer is mainly composed of a charge generation material, a solvent and a binder resin, and it contains additives such as a sensitizer, a dispersant, a surfactant, and silicone oil. Also good.
The charge generation layer is obtained by coating with the above coating solution and drying, and as this coating method, dip coating, spray coating, bead coating, nozzle coating, spinner coating, ring coating, etc. A known method can be used.
The thickness of the charge generation layer provided as described above is suitably about 0.01 to 5 μm, preferably 0.05 to 2 μm. Further, drying after coating is performed by heating using an oven or the like. The drying temperature of the charge generation layer is preferably 50 to 160 ° C, more preferably 80 to 140 ° C.

(Charge transport layer)
The charge transport layer (37) is a layer having a charge transport function. A charge transport material having a charge transport function and a binder resin are dissolved or dispersed in an appropriate solvent, and this is coated on the charge generation layer (35) and dried. To form.
Charge transport materials include hole transport materials and electron transport materials.
Examples of the electron transport material include chloranil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2, 4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7- Examples thereof include electron-accepting substances such as trinitrodibenzothiophene-5,5-dioxide and benzoquinone derivatives.

  Examples of hole transport materials include poly (N-vinylcarbazole) and derivatives thereof, poly (γ-carbazolylethyl glutamate) and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, and oxazole. Derivatives, oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, aminobiphenyl derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9 -Styryl anthracene derivative, pyrazoline derivative, divinylbenzene derivative, hydrazone derivative, indene derivative, butadiene derivative, pyrene derivative, etc. Body, enamine derivatives and the like.

式（４）中、ｎは０又は１であり、Ａｒ₃及びＡｒ₄は、置換もしくは無置換のアリール基、又は置換もしくは無置換の複素環基を表わし、Ｒ₆〜Ｒ₈は、それぞれ独立して、水素原子、置換もしくは無置換のアルキル基、置換もしくは無置換のアルコキシ基、置換もしくは無置換のアリール基、置換もしくは無置換のアリールオキシ基、又は置換もしくは無置換の複素環基を表わし、Ｒ₇、Ｒ₈は、互いに結合して環を形成してもよく、Ａｒ₅は、置換もしくは無置換のアリーレン基を表わす。 These charge transport materials may be used alone or in combination of two or more. Among these, the compound represented by the following general formula (4) and the compound represented by the following general formula (5) are particularly effective in suppressing residual potential reduction and sensitivity deterioration.

In formula (4), n is 0 or 1, Ar ₃ and Ar ₄ represent a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, and R _{6 to} R ₈ are each independently And represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted heterocyclic group. , R ₇ and R ₈ may combine with each other to form a ring, and Ar ₅ represents a substituted or unsubstituted arylene group.

（上記一般式（５）中、Ａｒ₇は置換又は無置換の芳香族炭化水素基を表わす。Ａ₁、Ａ₂は下記一般式（６）で表わされ、同一でも異なっていてもよい。）

（上記一般式（６）中、Ａｒ₈、Ａｒ₉、Ａｒ₁₀は置換又は無置換の芳香族炭化水素基を表わす。また、Ａｒ₈とＡｒ₉、Ａｒ₉とＡｒ₁₀、Ａｒ₁₀とＡｒ₈は結合して複素環を形成してもよい。）

(In the general formula (5), Ar ₇ represents a substituted or unsubstituted aromatic hydrocarbon group. A ₁ and A ₂ are represented by the following general formula (6), which may be the same or different. )

(In the above general formula (6), Ar ₈ , Ar ₉ and Ar ₁₀ represent a substituted or unsubstituted aromatic hydrocarbon group. Ar ₈ and Ar ₉ , Ar ₉ and Ar ₁₀ , Ar ₁₀ and Ar ₈ May combine to form a heterocyclic ring.)

Specific examples of the compound represented by the general formula (4) include the following.

Specific examples of the distyrylbenzene compound represented by the general formula (5) include the following.

  Binder resins include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, poly Vinylidene chloride, polyarylate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly (N-vinylcarbazole), acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, Thermoplastic or thermosetting resins such as phenol resin and alkyd resin can be mentioned, among which polycarbonate and polyarylate are preferable.

  As the solvent used, tetrahydrofuran, dioxane, toluene, cyclohexanone, methyl ethyl ketone, xylene, acetone, diethyl ether, methyl ethyl ketone and the like are used. These may be used singly or in combination of two or more.

The charge transport layer is obtained by coating with the coating solution and then heating and drying in an oven or the like. In the present invention, the drying temperature of the charge transport layer varies depending on the kind of the solvent contained in the coating liquid for the charge transport layer as described above, but is preferably 80 to 150 ° C, more preferably 100 to 140 ° C. .
The amount of the charge transport material is appropriately 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin.

If necessary, a plasticizer and a leveling agent can be added.
As the plasticizer that can be used in combination with the charge transport layer, those used as plasticizers for commonly used resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is 100 wt. About 0 to 30 parts by weight per part is appropriate.
Leveling agents that can be used in combination with the charge transport layer include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain. The amount used is a binder resin. About 0 to 1 part by weight is appropriate for 100 parts by weight.

  The thickness of the charge transport layer is suitably about 5 to 40 μm, preferably about 10 to 30 μm.

<Crosslinked charge transport layer>
The crosslinkable charge transport layer used in the present invention comprises at least a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure (hereinafter referred to as “ Those formed by polymerization (also referred to as “polymerization”) are preferred. First, the constituent materials of the coating solution for the crosslinked charge transport layer before polymerizing the crosslinked charge transport layer will be described.

  Examples of the trifunctional or higher functional radical polymerizable monomer having no charge transport property used in the present invention include a hole transport structure such as triarylamine, hydrazone, pyrazoline, carbazole, condensed polycyclic quinone, diphenoquinone, cyano group. And a monomer having no electron transport structure such as an electron-withdrawing aromatic ring having a nitro group and having three or more radical polymerizable functional groups. The radical polymerizable functional group may be any group as long as it has a carbon-carbon double bond and is capable of radical polymerization.

Examples of these radical polymerizable functional groups include 1-substituted ethylene functional groups and 1,1-substituted ethylene functional groups shown in the following (1) to (2).
(1) Examples of the 1-substituted ethylene functional group include functional groups represented by the following formulas.
CH ₂ = CH—X ₁ −... (10)
However, in Formula (10), X ₁ is an arylene group such as an optionally substituted phenylene group or naphthylene group, an optionally substituted alkenylene group, —CO— group, —COO. - group, -CON (R ₁₀₎ - group (R ₁₀ is hydrogen, alkyl group such as a methyl group, an ethyl group, a benzyl group, naphthylmethyl group, an aralkyl group such as a phenethyl group, a phenyl group, an aryl such as naphthyl group Represents a group) or -S- group.
Specific examples of the substituent 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) Examples of the 1,1-substituted ethylene functional group include functional groups represented by the following formulas.
CH ₂ = C (Y) -X ₂ −... (11)
However, in formula (11), Y represents an alkyl group which may have a substituent, an aralkyl group which may have a substituent, a phenyl group which may have a substituent, a naphthyl group, and the like. Aryl group, halogen atom, cyano group, nitro group, alkoxy group such as methoxy group or ethoxy group, -COOR ₁₁ group (R ₁₁ is a hydrogen atom, an optionally substituted methyl group, ethyl group, etc. An alkyl group, an aralkyl group such as benzyl or phenethyl group which may have a substituent, an aryl group such as a phenyl group or naphthyl group which may have a substituent, or -CONR ₁₂ R ₁₃ (R ₁₂ And R ₁₃ represents a hydrogen atom, an alkyl group such as an optionally substituted methyl group or an ethyl group, an aralkyl group such as an optionally substituted benzyl group, naphthylmethyl group, or phenethyl group. , Other substituent a phenyl group which may have a represents an aryl group such as a naphthyl group, which may be the same or different from each other.) Further, X ₂ is the formula X ₁ same as in (10) A substituent, a single bond, and an alkylene group are represented, provided that at least one of Y 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 include, for example, a halogen atom, a nitro group, a cyano group, a methyl group, an alkyl group such as an ethyl group, a methoxy group, an ethoxy group, and the like And an aryloxy group such as a phenyl group and a naphthyl group, an aralkyl group such as a benzyl group and a phenethyl group, and the like.

  Among these radical polymerizable functional groups, acryloyloxy group and methacryloyloxy group are particularly useful, and a compound having three or more acryloyloxy groups is, for example, a compound having three or more hydroxyl groups in the molecule and an acrylic group. It can be obtained by using an acid (salt), an acrylic acid halide, or an acrylic ester to cause an ester reaction or a transesterification reaction. A compound having three or more methacryloyloxy groups can be obtained in the same manner. Further, the radical polymerizable functional groups in the monomer having three or more radical polymerizable functional groups may be the same or different.

Specific examples of the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure include the following, but are not limited to these compounds.
That is, examples of the radical polymerizable monomer used in the present invention include trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, HPA-modified trimethylolpropane triacrylate, EO-modified trimethylolpropane triacrylate, and PO-modified. Trimethylolpropane triacrylate, caprolactone-modified trimethylolpropane triacrylate, HPA-modified trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol triacrylate, ECH-modified glycerol triacrylate, EO-modified glycerol triacrylate , PO-modified glycerol triacrylate, Lith (acryloxyethyl) isocyanurate, dipentaerythritol hexaacrylate (DPHA), caprolactone-modified dipentaerythritol hexaacrylate, dipentaerythritol hydroxypentaacrylate, alkyl-modified dipentaerythritol pentaacrylate, alkyl-modified dipentaerythritol tetraacrylate, alkyl Modified dipentaerythritol triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, EO modified phosphoric acid triacrylate, 2,2,5,5-tetrahydroxymethylcyclopentanone tetraacrylate, etc. These may be used alone or in combination of two or more.

  In addition, the trifunctional or higher functional radical polymerizable monomer having no charge transport structure used in the present invention has a molecular weight relative to the number of functional groups in the monomer in order to form a dense crosslink in the crosslinkable charge transport layer. The ratio (molecular weight / functional group number) is preferably 250 or less. Further, when this ratio is larger than 250, the cross-linked charge transport layer is soft and wear resistance is somewhat lowered. Therefore, among the monomers exemplified above, monomers having a modifying group such as HPA, EO, PO are extremely It is not preferable to use a compound having a long modifying group alone. Further, the proportion of the trifunctional or higher functional radical polymerizable monomer having no charge transport structure used in the crosslinkable charge transport layer is 20 to 80% by weight, preferably 30 to 70% by weight based on the total amount of the crosslinkable charge transport layer. %, Which substantially depends on the proportion of the trifunctional or higher-functional radical polymerization reactive monomer in the solid content of the coating liquid. When the monomer component is less than 20% by weight, the three-dimensional crosslink density of the crosslinkable charge transport layer is small, and a drastic improvement in wear resistance is not achieved as compared with the case of using a conventional thermoplastic binder resin. On the other hand, if it exceeds 80% by weight, the content of the charge transporting compound is lowered, and the electrical characteristics are deteriorated. The electrical characteristics and abrasion resistance required differ depending on the process used, and the film thickness of the cross-linked charge transport layer of the photoreceptor varies accordingly. A range of 70% by weight is most preferred.

(Radically polymerizable compound having a monofunctional charge transporting structure)
The radical polymerizable compound having a monofunctional charge transport structure used in the crosslinked charge transport layer of the present invention is, for example, a hole transport structure such as triarylamine, hydrazone, pyrazoline, carbazole, such as condensed polycyclic quinone. , A compound having an electron transport structure such as diphenoquinone, an electron-withdrawing aromatic ring having a cyano group or a nitro group, and having one radical polymerizable functional group. Examples of the radical polymerizable functional group include functional groups represented by the above formula (10) or formula (11). More specifically, those shown in the above radical polymerizable monomer can be mentioned, and acryloyloxy group and methacryloyloxy group are particularly useful. In addition, a triarylamine structure is highly effective as a charge transporting structure, and in particular, when a compound represented by the structure of the following general formula (1) or (2) is used, electrical characteristics such as sensitivity and residual potential are good. To last.

（式中、Ｒ₁は水素原子、ハロゲン原子、置換基を有してもよいアルキル基、置換基を有してもよいアラルキル基、置換基を有してもよいアリール基、シアノ基、ニトロ基、アルコキシ基、−ＣＯＯＲ₇（Ｒ₇は水素原子、置換基を有してもよいアルキル基、置換基を有してもよいアラルキル基又は置換基を有してもよいアリール基）、ハロゲン化カルボニル基若しくはＣＯＮＲ₈Ｒ₉（Ｒ₈及びＲ₉は水素原子、ハロゲン原子、置換基を有してもよいアルキル基、置換基を有してもよいアラルキル基又は置換基を有してもよいアリール基を示し、互いに同一であっても異なっていてもよい）を表わし、Ａｒ₁、Ａｒ₂は置換もしくは無置換のアリーレン基を表わし、同一であっても異なってもよい。Ａｒ₃、Ａｒ₄は置換もしくは無置換のアリール基を表わし、同一であっても異なってもよい。Ｘは単結合、置換もしくは無置換のアルキレン基、置換もしくは無置換のシクロアルキレン基、置換もしくは無置換のアルキレンエーテル基、酸素原子、硫黄原子、ビニレン基を表わす。Ｚは置換もしくは無置換のアルキレン基、置換もしくは無置換のアルキレンエーテル基、アルキレンオキシカルボニル基を表わす。ｍ、ｎは０〜３の整数を表わす。）

(Wherein R ₁ is a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a cyano group, a nitro group, Group, alkoxy group, —COOR ₇ (R ₇ is a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent or an aryl group which may have a substituent), halogen Carbonyl group or CONR ₈ R ₉ (R ₈ and R ₉ may have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Ar ₁ and Ar ₂ each represents a substituted or unsubstituted arylene group and may be the same or different.Ar ₃ , which may be the same or different from each other. Ar ₄ Ali substituted or unsubstituted X may be the same or different, and X is 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, sulfur An atom and a vinylene group, Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group, and an alkyleneoxycarbonyl group, m and n represent an integer of 0 to 3)

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

Ar ₃ and Ar ₄ represent a substituted or unsubstituted aryl group. In the present invention, the aryl group includes a condensed polycyclic hydrocarbon group, a non-condensed cyclic hydrocarbon group, and a heterocyclic group.
The condensed polycyclic hydrocarbon group preferably has 18 or less carbon atoms forming a ring, for example, a pentanyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptaenyl group, a biphenylenyl group, an as-indacenyl group. , S-indacenyl group, fluorenyl group, acenaphthylenyl group, preadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrenyl group, aceanthrylenyl group, triphenylyl group, pyrenyl group , A chrycenyl group, a naphthacenyl group, and the like.

Examples of the non-fused cyclic hydrocarbon group include monovalent groups of monocyclic hydrocarbon compounds such as benzene, diphenyl ether, polyethylene diphenyl ether, diphenyl thioether and diphenyl sulfone, or biphenyl, polyphenyl, diphenylalkane, diphenylalkene, diphenylalkyne, Monovalent groups of non-condensed polycyclic hydrocarbon compounds such as triphenylmethane, distyrylbenzene, 1,1-diphenylcycloalkane, polyphenylalkane, and polyphenylalkene, or ring assemblies such as 9,9-diphenylfluorene And monovalent groups of hydrocarbon compounds.
Examples of the heterocyclic group include monovalent groups such as carbazole, dibenzofuran, dibenzothiophene, oxadiazole, and thiadiazole.

The aryl group represented by Ar ₃ or Ar ₄ may have a substituent as shown below, for example.
(1) Halogen atom, cyano group, nitro group and the like.
(2) alkyl group, preferably a number of 1 to 12 carbon (hereinafter, C ₁ -C ₁₂ is described as including a) especially C ₁ -C _8, more preferably a linear or branched C ₁ -C ₄ an alkyl group, a fluorine atom in the alkyl group, a hydroxyl group, a cyano group, an alkoxy group of C ₁ -C _4, a phenyl group or a halogen atom, C ₁ of -C ₄ alkyl or C ₁ -C ₄ You may have the phenyl group substituted by the 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 ₂ ), and R ₂ 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. It may contain an alkoxy group having C ₁ -C _4, alkyl group, or a halogen atom C ₁ -C ₄ 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.

（式中、Ｒ₃及びＲ₄は各々独立に水素原子、前記（２）で定義したアルキル基、またはアリール基を表わす。アリール基としては、例えばフェニル基、ビフェニル基又はナフチル基が挙げられ、これらはＣ₁〜Ｃ₄のアルコキシ基、Ｃ₁〜Ｃ₄のアルキル基またはハロゲン原子を置換基として含有してもよい。Ｒ₃及びＲ₄は共同で環を形成してもよい）
具体的には、アミノ基、ジエチルアミノ基、Ｎ−メチル−Ｎ−フェニルアミノ基、Ｎ，Ｎ−ジフェニルアミノ基、Ｎ，Ｎ−ジ（トリール）アミノ基、ジベンジルアミノ基、ピペリジノ基、モルホリノ基、ピロリジノ基等が挙げられる。 (6)

(Wherein R ₃ and R ₄ each independently represent a hydrogen atom, an alkyl group defined in (2) above, or an aryl group. Examples of the aryl group include a phenyl group, a biphenyl group, and a naphthyl group, these may form a ring C ₁ -C ₄ alkoxy groups, C ₁ -C a alkyl group or a halogen atom ₄ which may contain as substituents .R ₃ and R ₄ jointly)
Specifically, amino group, diethylamino group, N-methyl-N-phenylamino group, N, N-diphenylamino group, N, N-di (tolyl) amino group, dibenzylamino group, piperidino group, morpholino group And pyrrolidino group.

(7) An alkylenedioxy group or an alkylenedithio group such as a methylenedioxy group or a methylenedithio group.
(8) A substituted or unsubstituted styryl group, a substituted or unsubstituted β-phenylstyryl group, a diphenylaminophenyl group, a ditolylaminophenyl group, and the like.

The arylene group represented by Ar ₁ or Ar ₂ is a divalent group derived from the aryl group represented by Ar ₃ or Ar ₄ .
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 C _{1 to} C ₁₂ , preferably C _{1 to} C ₈ , more preferably a C _{1 to} C ₄ linear or branched alkylene group, and these alkylene groups include a fluorine atom, a hydroxyl group, a cyano group, optionally having a C ₁ -C ₄ alkoxy group, a phenyl group or a halogen atom, C ₁ -C ₄ alkyl or C1~C4 phenyl group substituted by an alkoxy group Also good. 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 C _{5 to} C ₇ cyclic alkylene group, and these cyclic alkylene groups include a fluorine atom, a hydroxyl group, a C _{1 to} C ₄ alkyl group, and a C _{1 to} C ₄ alkyl group. It may have an alkoxy group. 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 group of the alkylene ether group is a hydroxyl group, a methyl group, an ethyl group And the like.

で表わされ、Ｒ₅は水素、アルキル基（前記（２）で定義されるアルキル基と同じ）、アリール基（前記Ａｒ₃、Ａｒ₄で表わされるアリール基と同じ）、ａは１または２、ｂは１〜３の整数を表わす。 The vinylene group is

R ₅ is hydrogen, an alkyl group (same as the alkyl group defined in (2) above), an aryl group (same as the aryl group represented by Ar ₃ or Ar ₄ above), a is 1 or 2 , B represents an integer of 1 to 3.

Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group, or an alkyleneoxycarbonyl group.
Examples of the substituted or unsubstituted alkylene group include the same alkylene groups as those described above for X.
Examples of the substituted or unsubstituted alkylene ether group include the alkylene ether group represented by X.
Examples of the alkyleneoxycarbonyl group include a caprolactone-modified group.

（式中、ｏ、ｐ、ｑはそれぞれ０又は１の整数、Ｒａは水素原子、メチル基を表わし、Ｒｂ、Ｒｃは水素原子以外の置換基で炭素数１〜６のアルキル基を表わし、複数の場合は異なっても良い。ｓ、ｔは０〜３の整数を表わす。Ｚａは単結合、メチレン基、エチレン基、

を表わす。）
上記一般式で表わされる化合物としては、Ｒｂ、Ｒｃの置換基として、特にメチル基、エチル基である化合物が好ましい。 Further, the radical polymerizable compound having a monofunctional charge transport structure of the present invention is more preferably a compound having a structure of the following general formula (3).

(Wherein, o, p and q are each an integer of 0 or 1, Ra represents a hydrogen atom or a methyl group, Rb and Rc represent a substituent other than a hydrogen atom and an alkyl group having 1 to 6 carbon atoms, And s and t each represents an integer of 0 to 3. Za is a single bond, a methylene group, an ethylene group,

Represents. )
As the compound represented by the above general formula, a compound having a methyl group or an ethyl group as a substituent for Rb and Rc is particularly preferable.

  The radically polymerizable compound having a monofunctional charge transport structure represented by the general formulas (1) and (2), particularly (3) used in the present invention is polymerized with the carbon-carbon double bond open on both sides. Therefore, it does not become a terminal structure but is incorporated in the chain polymer. In addition, in a polymer formed by crosslinking with a radically polymerizable monomer having three or more functional groups, it exists in the main chain of the polymer and exists in the cross-linked chain between the main chain and the main chain (in this cross-linked chain). Is an intermolecular cross-linked chain between one polymer and another polymer, a portion of the main chain folded in one polymer, and another derived from a monomer polymerized at a position away from the main chain. And an intramolecular cross-linked chain that is cross-linked). Whether it is present in the main chain or in the cross-linked chain, the triarylamine structure suspended from the chain portion is composed of at least three aryl groups arranged radially from the nitrogen atom. And is bulky. Since this is not directly bonded to the chain part but is suspended from the chain part via a carbonyl group or the like, it is fixed in a state where it has flexibility in steric positioning. Since it is possible to arrange spatially adjacent to each other moderately, there is little structural distortion in the molecule. In addition, when the surface layer of the electrophotographic photosensitive member is used, it is presumed that an intramolecular structure that is relatively free from interruption of the charge transport path can be adopted.

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

Further, the radical polymerizable compound having a monofunctional charge transport structure used in the present invention is important for imparting the charge transport performance of the crosslinked charge transport layer. -80% by weight, preferably 30-70% by weight. If this component is less than 20% by weight, the charge transport performance of the crosslinkable charge transport layer cannot be maintained sufficiently, and deterioration of electrical characteristics such as a decrease in sensitivity and an increase in residual potential will occur with repeated use.
On the other hand, if it exceeds 80% by weight, the content of the trifunctional monomer having no charge transport structure is lowered, and the crosslink density is lowered, so that high wear resistance is not exhibited. The electrical characteristics and abrasion resistance required differ depending on the process used, and the film thickness of the cross-linked charge transport layer of the photoreceptor varies accordingly. A range of 70% by weight is most preferred.

  The crosslinkable charge transport layer of the present invention is obtained by polymerizing (curing) at least a trifunctional or higher radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. In addition, monofunctional and bifunctional radically polymerizable monomers, functional monomers, for the purpose of imparting functions such as viscosity adjustment during coating, stress relaxation of the cross-linked charge transport layer, lower surface energy and reduced friction coefficient, And radically polymerizable oligomers can be used in combination. Known radical polymerizable monomers and oligomers can be used.

  Polysiloxanes such as acryloyl polydimethylsiloxane ethyl, methacryloyl polydimethylsiloxane ethyl, acryloyl polydimethylsiloxane propyl, acryloyl polydimethylsiloxane butyl, diacryloyl polydimethylsiloxane diethyl having 20 to 70 repeating units of siloxane skeleton (polydimethylsiloxane skeleton) Examples of the radically polymerizable monomer or functional monomer include vinyl monomers having a group, acrylate, and methacrylate.

Examples of the radical polymerizable oligomer include epoxy acrylate, urethane acrylate, and polyester acrylate oligomers.
However, if a large amount of monofunctional and bifunctional radically polymerizable monomers and radically polymerizable oligomers are contained, the three-dimensional crosslink density of the crosslinkable charge transport layer is substantially decreased, leading to a decrease in wear resistance. For this reason, the content of these monomers and oligomers is limited to 50 parts by weight or less, preferably 30 parts by weight or less, with respect to 100 parts by weight of the tri- or higher functional radical polymerizable monomer.

  The crosslinked charge transport layer of the present invention is obtained by polymerizing at least a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. Accordingly, a polymerization initiator may be contained in the cross-linked charge transport layer coating solution in order to allow the polymerization reaction to proceed efficiently. Examples of such a polymerization initiator include the following thermal polymerization initiators and photopolymerization initiators.

  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 and 1-phenyl-1,2-propane-dione-2- (o-ethoxycarbonyl) oxime , Benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether Benzoin ether photopolymerization initiators such as ter, benzoin isopropyl ether, benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoylphenyl ether, acrylated benzophenone, Benzophenone photopolymerization initiators such as 1,4-benzoylbenzene, thioxanthones such as 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone Examples of other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzo Ruphenylethoxyphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9, Examples thereof include 10-phenanthrene, acridine compounds, triazine compounds, and imidazole compounds. Moreover, what has a photopolymerization acceleration effect can also be used individually or in combination with the said photoinitiator. Examples include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, 4,4'-dimethylaminobenzophenone, and the like.

  These polymerization initiators may be used alone or in combination of two or more. The content of the polymerization initiator is 0.5 to 40 parts by weight, preferably 1 to 20 parts by weight with respect to 100 parts by weight of the total content having radical polymerizability.

  Furthermore, the crosslinkable charge transport layer coating solution used in the present invention includes various plasticizers (for the purpose of stress relaxation and adhesion improvement), leveling agents, low molecular charge transport materials having no radical reactivity, etc. as necessary. Additives can be included. 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 wt% or less, preferably 10 wt% or less. Moreover, as leveling agents, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain can be used, and the amount used is based on the total solid content of the coating liquid. 3% by weight or less is appropriate.

  The crosslinkable charge transport layer of the present invention comprises a coating liquid containing at least a trifunctional or higher-functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. It is formed by coating and curing on the transport layer. When the radically polymerizable monomer 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. Solvents used at this time include 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, tetrahydrofuran, dioxane and propyl ether. And ethers such as dichloromethane, dichloroethane, trichloroethane and chlorobenzene, aromatics such as benzene, toluene and xylene, cellosolves such as methyl cellosolve, ethyl cellosolve and cellosolve acetate. These solvents may be used alone or in combination of two or more. The dilution ratio with the solvent varies depending on the solubility of the composition, the coating method, and the target film thickness, and is arbitrary. The coating can be performed using a dip coating method, spray coating, bead coating, ring coating method or the like.

In this invention, after apply | coating the bridge | crosslinking type charge transport layer coating liquid which concerns, energy is given from the outside and it hardens | cures and forms a bridge type charge transport layer. 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 more and 170 ° C. or less, and if it is less 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 large distortion, a large number of unreacted residues, and reaction termination terminals are generated in the cross-linked charge transport layer. In order to advance 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 light, UV irradiation light sources such as high-pressure mercury lamps and metal halide lamps, which mainly have an emission wavelength in ultraviolet light, can be used, but a visible light source can also be selected according to the absorption wavelength of radically polymerizable substances and photopolymerization initiators. Is possible. Irradiation light amount is 50 mW / cm ² or more, preferably 1000 mW / cm ² or less, it takes time for the curing reaction is less than 50 mW / cm ^2. If it is higher than 1000 mW / cm ^2, the progress of the reaction becomes non-uniform, and local flaws are generated on the surface of the cross-linked charge transport layer, or many unreacted residues and reaction termination ends are generated. 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 film thickness of the crosslinkable charge transport layer used in the present invention is 1 μm or more and 10 μm or less, more preferably 2 μm or more and 8 μm or less. When it is thicker than 10 μm, cracks and film peeling are likely to occur as described above, and when it is 8 μm or less, the margin is further improved, so that the crosslinking density can be increased, and material selection and polymerization that further increase the wear resistance are possible. Conditions can be set. On the other hand, the radical polymerization reaction is susceptible to oxygen inhibition, that is, the surface in contact with the atmosphere may not be cross-linked or become uneven due to the influence of radical trapping by oxygen. This effect is noticeable when the surface layer is 1 μm or less, and the cross-linked charge transport layer having a thickness of less than this thickness is liable to cause a decrease in wear resistance or uneven wear. In addition, mixing of the lower layer charge transport layer component occurs during the application of the crosslinkable charge transport layer. If the coating thickness of the crosslinkable charge transport layer is thin, contaminants spread throughout the layer, resulting in inhibition of the polymerization reaction and a decrease in crosslink density. For these reasons, the cross-linked charge transport layer of the present invention has a good wear resistance and scratch resistance at a film thickness of 1 μm or more, but a portion that is locally scraped to the lower charge transport layer is formed in repeated use. And the wear of the portion increases, and the density unevenness of the halftone image is likely to occur due to the chargeability and sensitivity fluctuation. Therefore, it is desirable that the film thickness of the crosslinkable charge transport layer be 2 μm or more for a longer life and higher image quality.

  In the present invention, the charge generation layer, the charge transport layer, and the crosslinkable charge transport layer are sequentially laminated. When the outermost crosslinkable charge transport layer is insoluble in the organic solvent, the wear resistance, scratch resistance, Sex is achieved. As a method for testing the solubility in an organic solvent, a drop of an organic solvent having high solubility in a polymer substance, for example, tetrahydrofuran, dichloromethane, or the like, is dropped on the surface layer of the photoconductor, and the surface shape of the photoconductor is dried after natural drying. It can be determined by observing the change with a stereomicroscope. Dissolving photoconductors have a phenomenon that the central part of the droplet becomes concave and the surroundings swell in reverse, the charge transport material precipitates and the turbidity and cloudiness due to crystallization occur, and the surface swells and then shrinks, causing wrinkles Changes such as the phenomenon to be seen. In contrast, an insoluble photoconductor does not exhibit the above-described phenomenon, and does not change at all as before dropping.

  In the constitution of the present invention, in order to make the crosslinkable charge transport layer insoluble in the organic solvent, (1) composition of the crosslinkable charge transport layer coating solution, adjustment of the content ratio thereof, (2) crosslinkable charge Dilution solvent of transport layer coating solution, adjustment of solid content concentration, (3) Selection of coating method of crosslinkable charge transport layer, (4) Control of curing condition of crosslinkable charge transport layer, (5) Charge of lower layer It is important to control these, such as making the transport layer difficult to dissolve, but it is not achieved by a single factor.

  The composition of the crosslinkable charge transport layer coating liquid includes radical polymerization in addition to the above-described trifunctional or higher radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. When a large amount of additives such as binder resins, antioxidants, and plasticizers that do not have a functional functional group are included, the crosslinking density is reduced, the cured product resulting from the reaction and phase separation of the above additives occur, and the organic solvent It becomes soluble to. Specifically, it is important to suppress the total content to 20% by weight or less with respect to the total solid content of the coating liquid. Further, in order not to dilute the crosslinking density, the total content of monofunctional or bifunctional radical polymerizable monomers, reactive oligomers, and reactive polymers is 20% by weight or less based on the trifunctional radical polymerizable monomers. It is desirable. Further, when a large amount of a radical polymerizable compound having a bifunctional or higher functional charge transporting structure is contained, a bulky structure is fixed in the crosslinked structure by a plurality of bonds, so that distortion is likely to occur. It is easy to become an aggregate. This can cause solubility in organic solvents. Although different depending on the compound structure, the content of the radical polymerizable compound having a bifunctional or higher functional charge transporting structure is preferably 10% by weight or less based on the radical polymerizable compound having a monofunctional charge transporting structure.

  Regarding the diluting solvent of the crosslinkable charge transport layer coating solution, if a solvent with a low evaporation rate is used, the remaining solvent may interfere with curing or increase the amount of the lower layer component mixed, resulting in uneven curing. And the cured density is reduced. For this reason, it tends to be soluble in organic solvents. Specifically, tetrahydrofuran, a mixed solvent of tetrahydrofuran and methanol, ethyl acetate, methyl ethyl ketone, ethyl cellosolve and the like are useful, but are selected according to the coating method. Moreover, regarding the solid content concentration, if it is too low for the same reason, it tends to be soluble in an organic solvent. Conversely, the upper limit concentration is constrained by the limitations of film thickness and coating solution viscosity. Specifically, it is desirable to use in the range of 10 to 50% by weight. As the coating method for the cross-linked charge transport layer, for the same reason, the solvent content at the time of forming the coating film, the method of reducing the contact time with the solvent is preferable, specifically, the spray coating method, the amount of coating liquid A ring coat method in which the above is regulated is preferable. In order to suppress the amount of the lower layer component mixed, it is also effective to use a polymer charge transport material as the charge transport layer and to provide an insoluble intermediate layer for the coating solvent for the cross-linked charge transport layer.

As curing conditions for the cross-linked charge transport layer, if the energy of heating or light irradiation is low, the curing is not completely completed and the solubility in the organic solvent is increased. On the other hand, when cured with very high energy, the curing reaction becomes non-uniform, and it tends to increase the number of uncrosslinked parts and radical stopping parts and to form an aggregate of minute cured products. For this reason, it may become soluble in an organic solvent. To insolubilize in an organic solvent, the heat curing conditions are preferably 100 to 170 ° C. and 10 minutes to 3 hours, and the curing conditions by UV light irradiation are 50 to 1000 mW / cm ² and 5 seconds to 5 minutes. In addition, it is desirable to control the temperature rise to 50 ° C. or less to suppress non-uniform curing reaction.
After completion of curing, the photosensitive member of the present invention is obtained by further heating at 100 to 150 ° C. for 10 to 30 minutes to reduce the residual solvent.

<Intermediate layer>
In the photoreceptor of the present invention, an intermediate layer is provided between the charge transport layer and the crosslinked charge transport layer for the purpose of suppressing charge transport layer component mixing into the crosslinked charge transport layer or improving adhesion between the two layers. It is possible. For this reason, as the intermediate layer, those which are insoluble or hardly soluble in the cross-linked charge transport layer coating solution are suitable, and generally a binder resin is used as a main component. Examples of these resins include polyamide, alcohol-soluble nylon, water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol. As a method for forming the intermediate layer, a generally used coating method is employed as described above. In addition, about 0.05-2 micrometers is suitable for the thickness of an intermediate | middle layer.

<Underlayer>
In the photoreceptor of the present invention, an undercoat layer can be provided between the conductive support (31) and the photosensitive layer. In general, the undercoat layer is mainly composed of a resin. However, considering that the photosensitive layer is coated with a solvent on these resins, the resin may be a resin having high solvent resistance with respect to a general organic solvent. desirable. Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. Further, a metal oxide fine powder pigment exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like may be added to the undercoat layer in order to prevent moire and reduce residual potential.

These undercoat layers can be formed using an appropriate solvent and a coating method like the above-mentioned photosensitive layer. Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the undercoat layer of the present invention. In addition, in the undercoat layer of the present invention, Al ₂ O ₃ is provided by anodic oxidation, organic substances such as polyparaxylylene (parylene), SiO ₂ , SnO ₂ , TiO ₂ , ITO, CeO ₂ A material provided with an inorganic material such as a vacuum thin film can also be used favorably. In addition, known ones can be used. The thickness of the undercoat layer is suitably from 0 to 5 μm.

<Addition of antioxidant to each layer>
Further, in the present invention, in order to improve environmental resistance, in order to prevent a decrease in sensitivity and an increase in residual potential, in particular, a cross-linked charge transport layer, a charge transport layer, a charge generation layer, an undercoat layer, an intermediate layer An antioxidant can be added to each layer.

<Synthesis Example of Radical Polymerizable Compound Having Monofunctional Charge Transporting Structure>
The compound having a monofunctional charge transport structure in the present invention is synthesized, for example, by the method described in Japanese Patent No. 3164426. An example of this is shown below.
(1) Synthesis of hydroxy group-substituted triarylamine compound (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 a white crystal 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. Then, it stirred at 5 degreeC for 3 hours, and reaction was complete | finished. The reaction solution was poured into water and extracted with toluene. This extract was repeatedly washed with an aqueous sodium bicarbonate solution and water. Thereafter, the solvent was removed from the toluene solution and purified 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 to 119.0 ° C.).

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is limited to a following example and is not interpreted. Note that “parts” used in the examples all represent parts by weight. The ratio represents a weight ratio.

  The evaluation device is a modified Ricoh digital copier (RICOH Pro C900), and the charging member is a scorotron charging member (the discharge wire is a tungsten-molybdenum alloy plated with 50 μm in diameter) and charged as follows. 780 nm LD light (image writing with polygon mirror, resolution 1200 dpi) as image exposure light source, development is performed with two-component development using black toner, transfer belt is used as a transfer member, and a static elimination lamp is used for static elimination. Using, it evaluated in the normal temperature normal humidity environment of 23 degreeC-55% RH.

(VL variation evaluation)
First, the developing unit of the evaluation apparatus was modified to attach a movable potential sensor that can be translated along the axial direction of the photosensitive member. This unit was set in an evaluation apparatus and VL measurement was performed.
The VL of the 10th sheet when 10 sheets of all solid images were printed in the vertical direction on A3 paper under the following charging conditions was measured. A commercially available surface electrometer was used for the measurement, and the numerical value of the surface electrometer was recorded with an oscilloscope at 100 signals or more per second.
Applied voltage to the wire: -6.0 KV
Grid voltage: -860V (the charged potential of the photoreceptor is -850V)
There are three measurement positions: the lower end, the upper end and the center of the photoreceptor. In this case, the upper end of the photosensitive member is 41.5 mm from the upper end of the support, the lower end is 338.5 mm, and the center is 190 mm.
ΔVL is the difference between the maximum value and the minimum value of all measured values (excluding numerical values that are considered to be measurement errors due to obvious noise) measured with an oscilloscope, measured at the top, center, and bottom.

(Evaluation of uneven image density in one page)
Five 2-by2 halftone images were printed on each of the two charging conditions under the same charging conditions as in the VL variation evaluation. Each image is measured with a commercially available spectral densitometer (X-Rite) at five or more locations within one page (total of four points near each of the four vertices and the center), and the maximum and minimum values are measured. The difference was defined as image density unevenness (ΔID) within one page, and the average value of the five output images was evaluated.

(Abrasion amount evaluation)
Under the same charging conditions as those at the time of VL variation evaluation, 200,000 sheets are continuously printed using a 6% writing rate chart, and image evaluation after printing and photosensitivity before and after printing using an eddy current film thickness measuring device. The thickness of the body was measured, the wear amount was calculated from the difference, and the wear amount was evaluated.

Next, a method for producing a photoreceptor used for evaluation will be described.
(Calculation example of formula (1))
Temporarily, when coating a support body having a length of 380 mm as shown in FIG. 3, the speed of insertion into the coating liquid is 25 mm / s, and the rest time in a state where the support body is all immersed in the coating liquid. 120 s, the speed at which the support is lifted from the coating solution is 5 mm / s, and the width of paper passing through the A4 paper in the horizontal direction is 300 mm. The center of the paper in the main scanning direction is the center of the photoconductor. When passing through the center, the upper end (101) of the photoconductor is 40 mm from the upper end of the support, the lower end (103) is 340 mm from the upper end of the support, and the center (102) is 190 mm from the upper end of the support. Using these, the equation (1) is calculated as follows.
A = 340/25 + 120 + 340/5 = 201.6 (s)
B = 40/25 + 120 + 40/5 = 129.6 (s)
C = 190/25 + 120 + 190/5 = 165.6 (s)
And
A−B / C = (201.6-129.6) /165.6≈0.43
It becomes.
In the calculation example, the insertion speed is 25 mm / s and the lifting speed is 5 mm / s. However, the actual coating is not limited to this, and even if the insertion speed and the lifting speed are changed, the insertion and the lifting are repeated. Coating may be performed.

<Example 1>
Preparation of electrophotographic photosensitive member 1 An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following composition are sequentially applied onto an aluminum cylinder having a diameter of 30 mm by a dip coating method. Then, drying was performed in an oven to form an undercoat layer of about 3.5 μm, a charge generation layer of about 0.2 μm, and a charge transport layer of about 20 μm. The drying conditions for each layer were 130 ° C. for the undercoat layer, 90 ° C. for the charge generation layer, and 135 ° C. for the charge transport layer, and each layer was dried for 20 minutes.

[Coating liquid for undercoat layer]
Titanium oxide (CR-EL, purity: 99.7%, average primary particle size: about 0.25 μm,
Specific resistance: 3.5 × 10 ⁹ Ω · cm, manufactured by Ishihara Sangyo Co., Ltd.) 50 parts Alkyd resin (Beckolite M6401-50, solid content: 50%,
Hydroxyl value: 130, manufactured by Dainippon Ink & Chemicals, Inc.) 14 parts Melamine resin (L-145-60, solid content: 60%, manufactured by Dainippon Ink & Chemicals, Inc.)
8 parts 2-butanone 120 parts [coating liquid for charge generation layer]
Bragg angle 2θ ± 0.2 degrees of 9.0 degrees, 14.2 degrees in X-ray diffraction of CuKα,
Titanyl phthalocyanine having strong peaks at 23.9 degrees and 27.1 degrees 8 parts Polyvinyl butyral (BX-1, manufactured by Sekisui Chemical Co., Ltd.) 5 parts 2-butanone 400 parts

シリコーンオイル（１００ｃＳｔ、信越化学製） ０．００２部
テトラヒドロフラン １００部
電荷輸送層を塗工する際、膜厚が約２０μｍとなる塗工速度で塗工するが、塗工液に支持体を任意の速度で浸漬させ、上端まで浸漬させた状態で一時停止する時間を任意の時間に設定し、Ａ＝１１５（ｓ）、Ｂ＝４１（ｓ）、Ｃ＝７８（ｓ）、（Ａ−Ｂ）／Ｃ＝０．９５となる塗工条件で塗工した。 [Coating fluid for charge transport layer]
Polycarbonate (trade name Z Polyca, manufactured by Teijin Chemicals Ltd.) 10 parts 7 parts of charge transport material A having the following structural formula

Silicone oil (100 cSt, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.002 parts Tetrahydrofuran 100 parts When coating the charge transport layer, it is applied at a coating speed that results in a film thickness of about 20 μm. Set the time to pause at the speed and soak up to the upper end to any time, A = 115 (s), B = 41 (s), C = 78 (s), (AB) The coating was performed under the coating conditions of /C=0.95.

[Formation of cross-linked charge transport layer]
On this charge transport layer, a coating solution for a crosslinkable charge transport layer having the following composition is spray-coated and naturally dried for 20 minutes, and then a metal halide lamp: 160 W / cm, irradiation distance: 120 mm, irradiation intensity: 500 mW / Light irradiation was performed under conditions of cm ² and irradiation time: 60 seconds to cure the coating film. Further, drying was performed at 130 ° C. for 20 minutes to provide a 5 μm cross-linked charge transport layer to obtain an electrophotographic photoreceptor of the present invention.
(Coating liquid for crosslinkable charge transport layer)
Trifunctional or higher functional radical polymerizable monomer having no charge transport structure:
Trimethylolpropane triacrylate (KAYARAD TMPTA,
Nippon Kayaku molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99)
10 parts Radical polymerizable compound having monofunctional charge transport structure (Exemplary Compound No. 54)
10 parts Photopolymerization initiator: 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals) 1 part Tetrahydrofuran 100 parts

<Example 2>
In Example 1, when the charge transport layer is applied, the support is immersed in the coating liquid at an arbitrary speed, and the time to pause in the state where the support is immersed to the upper end is set to an arbitrary time, and A = 136. (S), B = 62 (s), C = 99 (s), (A−B) / Electrophotographic photoreceptor in the same manner as in Example 1 except that coating is performed under the coating conditions of C = 0.75. Was made.
<Example 3>
In Example 1, when the charge transport layer is applied, the support is immersed in the coating liquid at an arbitrary speed, and the time during which the support is immersed in the upper end is set to an arbitrary time, and A = 184. (S), B = 110 (s), C = 147 (s), and (A−B) /C=0.50 Was made.
<Example 4>
In Example 1, when the charge transport layer is applied, the support is immersed in the coating solution at an arbitrary speed, and the time during which the support is immersed in the upper end is set to an arbitrary time, and A = 269. (S), B = 195 (s), C = 232 (s), and (A−B) /C=0.32. Was made.

<Example 5>
An electrophotographic photosensitive member was produced in the same manner as in Example 14 except that the charge transport material A contained in the charge transport layer coating solution was replaced with 7 parts of the charge transport material B having the following structural formula.
Charge transport material B 7 parts

<Example 6>
In Example 5, when the charge transport layer was applied, the support was immersed in the coating solution at an arbitrary speed, and the suspension time was set to an arbitrary time in a state where the support was immersed in the upper end. A = 136 (S), B = 62 (s), C = 99 (s), and (A−B) /C=0.75 The electrophotographic photosensitive member is the same as in Example 5 except that coating is performed under the coating conditions. Was made.
<Example 7>
In Example 5, when the charge transport layer was applied, the support was immersed in the coating solution at an arbitrary speed, and the time for pausing in the state of being immersed to the upper end was set to an arbitrary time, and A = 184 (S), B = 110 (s), C = 147 (s), ((A−B) /C=0.50), except that the coating is performed under the same conditions as in Example 5, except that coating is performed. The body was made.
<Example 8>
In Example 5, when the charge transport layer was applied, the support was immersed in the coating liquid at an arbitrary speed, and the suspension time was set to an arbitrary time in a state where the support was immersed up to the upper end. A = 269 (S), B = 195 (s), C = 232 (s), (A−B) / Electrophotographic photoreceptor in the same manner as in Example 5 except that coating is performed under the coating conditions such that C = 0.32. Was made.

<Example 9>
The radical polymerizable compound having a monofunctional charge transporting structure contained in the coating liquid for the crosslinkable charge transporting layer of Example 1 was exemplified as Compound No. 1. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that 144 parts and 10 parts were used.
<Example 10>
A trifunctional or higher-functional radical polymerizable monomer having no charge transporting structure contained in the coating liquid for a crosslinkable charge transporting layer of Example 9 and a trifunctional or higher functional radical having no charge transporting structure shown below. An electrophotographic photosensitive member was produced in the same manner as in Example 9 except that the photopolymerization initiator was changed to 1 part of the following compound instead of 10 parts of the functional monomer.
Trifunctional or higher functional radical polymerizable monomer having no charge transport structure:
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) 10 parts Photopolymerization initiator: 2,2-dimethoxy-1,2-diphenylethane-1-one (Irgacure 651, manufactured by Ciba Specialty Chemicals) 1 part

<Example 11>
A trifunctional or higher-functional radical polymerizable monomer having no charge transporting structure contained in the coating liquid for a crosslinkable charge transporting layer of Example 9 and a trifunctional or higher functional radical having no charge transporting structure shown below. An electrophotographic photosensitive member was produced in the same manner as in Example 9 except that 10 parts of the functional monomer was used.
Trifunctional or higher functional radical polymerizable monomer having no charge transport structure:
Caprolactone-modified dipentaerythritol hexaacrylate (KAYARAD DPCA-120, manufactured by Nippon Kayaku Co., Ltd. Molecular weight: 1947, number of functional groups:
6 functions, molecular weight / number of functional groups = 325) 10 parts

<Example 12>
The trifunctional radically polymerizable monomer having no charge transporting structure contained in the coating liquid for the crosslinkable charge transporting layer of Example 9 was replaced with the following bifunctional radically polymerizable monomer having no charge transporting structure: An electrophotographic photosensitive member was produced in the same manner as in Example 9 except for changing to 10 parts.
Bifunctional radically polymerizable monomer having no charge transporting structure:
1,6-hexanediol diacrylate (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight: 226, functional group number: bifunctional, molecular weight / functional group number = 113)
10 copies

<Example 13>
An electrophotographic photosensitive member was produced in the same manner as in Example 12 except that the film thickness of the crosslinked charge transport layer in Example 12 was changed to 1 μm.
<Example 14>
An electrophotographic photosensitive member was produced in the same manner as in Example 12 except that the thickness of the crosslinked charge transport layer in Example 12 was changed to 3 μm.
<Example 15>
An electrophotographic photosensitive member was produced in the same manner as in Example 12 except that the film thickness of the cross-linked charge transport layer in Example 12 was changed to 8 μm.

<Example 16>
An electrophotographic photosensitive member was produced in the same manner as in Example 12 except that the thickness of the crosslinked charge transport layer in Example 12 was changed to 10 μm.
<Example 17>
An electrophotographic photosensitive member was produced in the same manner as in Example 12, except that the thickness of the cross-linked charge transport layer in Example 12 was changed to 0.5 μm.
<Example 18>
An electrophotographic photosensitive member was produced in the same manner as in Example 12 except that the film thickness of the cross-linked charge transport layer in Example 12 was changed to 12 μm.

<Example 19>
An undercoating layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following composition are sequentially applied on an aluminum cylinder having a diameter of 30 mm by a dip coating method and dried in an oven. An undercoat layer of about 3.5 μm, a charge generation layer of about 0.2 μm, and a charge transport layer of about 25 μm were formed. The drying conditions for each layer were 130 ° C. for the undercoat layer, 90 ° C. for the charge generation layer, and 135 ° C. for the charge transport layer, and each layer was dried for 20 minutes.
[Coating liquid for undercoat layer]
Titanium oxide (CR-EL, purity: 99.7%, average primary particle size: about 0.25 μm,
Specific resistance: 3.5 × 10 ⁹ Ω · cm, manufactured by Ishihara Sangyo Co., Ltd.) 50 parts Alkyd resin (Beckolite M6401-50, solid content: 50%,
Hydroxyl value: 130, manufactured by Dainippon Ink & Chemicals, Inc.) 14 parts Melamine resin (L-145-60, solid content: 60%, manufactured by Dainippon Ink & Chemicals, Inc.)
8 parts 2-butanone 120 parts

シリコーンオイル（１００ｃＳｔ、信越化学製） ０．００２部
テトラヒドロフラン １００部
電荷輸送層を塗工する際、膜厚が約２０μｍとなる塗工速度で塗工するが、塗工液に支持体を任意の速度で浸漬させ、上端まで浸漬させた状態で一時停止する時間を任意の時間に設定し、Ａ＝１１５（ｓ）、Ｂ＝４１（ｓ）、Ｃ＝７８（ｓ）、（Ａ−Ｂ）／Ｃ＝０．９５となる塗工条件で塗工した。 [Coating liquid for charge generation layer]
Bragg angle 2θ ± 0.2 degrees of 9.0 degrees, 14.2 degrees in X-ray diffraction of CuKα,
Titanylphthalocyanine having strong peaks at 23.9 degrees and 27.1 degrees 8 parts Polyvinyl butyral (BX-1, manufactured by Sekisui Chemical Co., Ltd.) 5 parts 2-butanone 400 parts [coating liquid for charge transport layer]
Polycarbonate (trade name Z Polyca, manufactured by Teijin Chemicals Ltd.) 10 parts 7 parts of charge transport material A having the following structural formula

Silicone oil (100 cSt, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.002 parts Tetrahydrofuran 100 parts When applying the charge transport layer, the coating is applied at a coating speed of about 20 μm. Set the time to pause at the speed and soak up to the upper end to any time, A = 115 (s), B = 41 (s), C = 78 (s), (AB) The coating was performed under the coating conditions of /C=0.95.

<Example 20>
An electrophotographic photoreceptor was prepared in the same manner as in Comparative Example 7, except that the charge transport material A contained in the charge transport layer coating solution of Example 19 was replaced with 7 parts of the charge transport material B having the following structural formula.
Charge transport material B 7 parts

電荷輸送層を塗工する際の塗工条件はＡ＝１１５（ｓ）、Ｂ＝４１（ｓ）、Ｃ＝７８（ｓ）、（Ａ−Ｂ）／Ｃ＝０．９５となる条件である。 <Example 21>
An electrophotographic photoreceptor was prepared in the same manner as in Comparative Example 7, except that the charge transport material A contained in the charge transport layer coating liquid of Example 19 was replaced with 7 parts of the charge transport material C having the following structural formula.
Charge transport material C 7 parts

The coating conditions for coating the charge transport layer are those that satisfy A = 115 (s), B = 41 (s), C = 78 (s), and (A−B) /C=0.95. .

<Comparative Example 1>
When the charge transport layer of Example 1 is applied, the support is immersed in the coating liquid at an arbitrary speed, and the suspension time is set to an arbitrary time in a state where the support is immersed in the upper end, and A = 100 ( s), B = 26 (s), C = 63 (s), and (A−B) /C=1.18. Produced.
<Comparative example 2>
A radical polymerizable compound having a monofunctional charge transporting structure contained in the coating liquid for a crosslinkable charge transporting layer of Comparative Example 1 was exemplified as Compound No. 1. An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 1 except that 144 parts and 10 parts were used.

<Comparative Example 3>
The trifunctional radically polymerizable monomer having no charge transporting structure contained in the coating liquid for the crosslinkable charge transporting layer of Comparative Example 2 is replaced with the following bifunctional radically polymerizable monomer having no charge transporting structure. An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 2 except that the amount was changed to 10 parts.
Bifunctional radically polymerizable monomer having no charge transporting structure:
1,6-hexanediol diacrylate (Molecular weight: 226, manufactured by Wako Pure Chemical Industries, Ltd.)
Functional group number: bifunctional, molecular weight / functional group number = 113) 10 parts

<Comparative example 4>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 3, except that the thickness of the cross-linked charge transport layer in Comparative Example 3 was changed to 0.5 μm.
<Comparative Example 5>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 3 except that the thickness of the cross-linked charge transport layer in Comparative Example 3 was changed to 12 μm.
<Comparative Example 6>
When the charge transport layer of Example 19 was applied, the support was immersed in the coating solution at an arbitrary speed, and the suspension time was set to an arbitrary time in a state where the support was immersed in the upper end, and A = 100 ( s), B = 26 (s), C = 63 (s), and (A−B) /C=1.18. Produced.

<Comparative Example 7>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 6 except that the charge transport material A contained in the charge transport layer coating solution of Comparative Example 6 was replaced with 7 parts of the charge transport material B having the following structural formula.
Charge transport material B 7 parts

<Comparative Example 8>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 6 except that the charge transport material A contained in the charge transport layer coating solution of Comparative Example 6 was replaced with 7 parts of the charge transport material C having the following structural formula.
Charge transport material C 7 parts

The results of evaluation by the above evaluation methods using the photoreceptors shown in the respective examples are shown in the table.
[Evaluation criteria for VL variation (ΔVL) within one]
A: ΔVL ≦ 20V
○: 20V <ΔVL ≦ 40V
×: 40V <ΔVL
[Evaluation criteria for uneven image density in one page]
A: Good (ΔID ≦ 0.1)
○: Level that does not cause any practical problem (0.1 <ΔID ≦ 0.15)
×: Practical problem (0.15 <ΔID)

As is clear from the above results, the formation of a cross-linkable charge transport layer on the charge transport layer dip-coated under the condition satisfying the formula (1) tends to reduce the VL variation in one. Therefore, it is very effective for improving image quality.
At the interface between the charge generation layer and the charge transport layer, a concentration gradient of the charge generation material is formed due to the difference in immersion time between the upper and lower drums that occurs during coating. When applying the charge transport layer, Equation (1) It is considered that the coating under the satisfying conditions reduces the concentration gradient of the charge generation material at the interface and reduces the VL variation. Furthermore, by laminating the cross-linked charge transport layer, not only VL variation was reduced, but also the wear resistance was remarkably improved.

On the other hand, when the charge transport layer is applied under the condition not satisfying the formula (1), the VL variation is large between the upper and lower portions of the photosensitive member, and the image density unevenness in one page at the time of printing clearly occurs, and the image quality Caused a decline.
As a result, it is possible to achieve both high durability and high image quality, which had been a problem when forming a protective layer in the past, and realize a long life of the photosensitive member and further an image forming apparatus using the photosensitive member. It became possible.

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Static elimination lamp 3 Charge charger 5 Image exposure part 6 Developing unit 7 Charger before transfer 8 Registration roller 9 Transfer body (paper etc.)
DESCRIPTION OF SYMBOLS 10 Transfer charger 11 Separation charger 12 Separation claw 13 Charger before cleaning 14 Fur brush 15 Cleaning blade 16 Lubricant 17 Brush roller 18 Application blade 31 Conductive support 33 Photosensitive layer 35 Charge generation layer 37 Charge transport layer 39 Crosslinkable charge transport layer

Japanese Patent Laid-Open No. 11-258838 JP 2008-062131 A JP 2000-321796 JP 09-258461 A JP 2008-46167 A

Claims (11)

In the method for producing an electrophotographic photosensitive member in which at least a charge generation layer and a charge transport layer are laminated in this order on a conductive support, the charge transport layer is applied by dip coating under a condition satisfying Formula (1). A method for producing an electrophotographic photosensitive member.
Formula (1)
(AB) / C <1
(Here, A is the time during which the lower end of the effective writing range of the photosensitive member is immersed in the coating liquid, B is the time during which the upper end of the effective writing range of the photosensitive member is immersed in the coating solution, and C is the photosensitive member. The time during which the center of the effective writing range is immersed in the coating solution.)   2. The method for producing an electrophotographic photosensitive member according to claim 1, wherein a cross-linked charge transport layer is laminated on the charge transport layer, and the film thickness is 1 μm or more and 10 μm or less. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the charge transporting material contained in the charge transporting layer contains a compound represented by the following general formula (4).

(In the formula (4), n is 0 or 1, Ar ₃ and Ar ₄ represent a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, and R _{6 to} R ₈ are each represented by Independently, a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted heterocyclic group R ₇ and R ₈ may combine with each other to form a ring, and Ar ₅ represents a substituted or unsubstituted arylene group.) 3. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the charge transport material contained in the charge transport layer contains a distyrylbenzene compound represented by the following general formula (5).

(In the general formula (5), Ar ₇ represents a substituted or unsubstituted aromatic hydrocarbon group. A ₁ and A ₂ are represented by the following general formula (6), which may be the same or different. )

(In the above general formula (6), Ar ₈ , Ar ₉ and Ar ₁₀ represent a substituted or unsubstituted aromatic hydrocarbon group. Ar ₈ and Ar ₉ , Ar ₉ and Ar ₁₀ , Ar ₁₀ and Ar ₈ May combine to form a heterocyclic ring.)   The crosslinkable charge transport layer is formed by reaction curing at least a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. The method for producing an electrophotographic photosensitive member according to any one of claims 2 to 4, wherein:   6. The method for producing an electrophotographic photosensitive member according to claim 5, wherein the functional group of the radical polymerizable monomer is at least one functional group selected from an acryloyloxy group and a methacryloyloxy group.   The method for producing an electrophotographic photosensitive member according to claim 5 or 6, wherein the functional group of the radical polymerizable compound is an acryloyloxy group or a methacryloyloxy group.   The method for producing an electrophotographic photosensitive member according to claim 5, wherein the reaction-curing of the cross-linked charge transport layer is performed using a heating unit or a light energy irradiation unit.   An electrophotographic photosensitive member produced by the method for producing an electrophotographic photosensitive member according to claim 1.   An image forming apparatus comprising the electrophotographic photosensitive member according to claim 9.   The image forming apparatus is a tandem-type full-color image forming apparatus having a plurality of image forming units including at least a plurality of electrophotographic photosensitive members, a charging unit, an image exposing unit, a developing unit, and a cleaning unit. Item 15. The image forming apparatus according to Item 10.

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