JP2007206170A - Electrophotographic photoreceptor, and image forming method, image forming apparatus and process cartridge for image forming apparatus using the photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor free of defects relating to output picture quality of an image forming apparatus such as wear or scratches due to repeated use of the photoreceptor as well as having excellent electric characteristics. <P>SOLUTION: The electrophotographic photoreceptor has at least a photosensitive layer and a surface layer successively on a conductive support, wherein the surface layer is formed by crosslinking a compound having at least a charge transporting structure and a radical polymerizable monomer having no charge transporting structure by a light energy irradiating means. The electrophotographic photoreceptor is characterized in that: the surface layer is crosslinked by using at least one kind of sensitized dye and a polymerization initiator; the optical absorption spectrum of the compound having a charge transporting structure shows an absorption edge wavelength λe (nm) in the longer wavelength side of less than 480 nm; and the maximum absorption wavelength λmax (nm) of the sensitized dye ranges from λe (nm) to 500 nm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  In recent years, organic photoreceptors have been widely used for electrophotographic photoreceptors (hereinafter also simply referred to as photoreceptors). Organic photoreceptors are advantageous over inorganic photoreceptors due to the fact that materials that can be used for various exposure light sources from visible light to infrared light can be easily developed, materials that are free from environmental pollution can be selected, and manufacturing costs are low. There are many points. However, organic photoconductors have weak physical and chemical strengths, and have drawbacks such that wear and scratches are likely to occur due to long-term use.

  An electrophotographic image forming apparatus is generally an electrophotographic photosensitive member, a charger for charging the electrophotographic photosensitive member, and a latent image for forming an electrostatic latent image on the surface of the electrophotographic photosensitive member charged by the charger. The image forming apparatus includes an image forming device, a developing device that attaches toner to the image portion of the electrostatic latent image formed by the latent image forming device, and a transfer device that transfers the toner attached to the image portion to the transfer object. Some of them are equipped with a cleaning device that removes toner remaining on the surface of the photoreceptor without being transferred, if necessary. Since toner remaining on the surface of the photoconductor after the transfer contributes to image quality deterioration, a cleaning device is employed in many image forming apparatuses.

  As the cleaning device, a brush, a magnetic brush, a blade, or the like is generally used. For brush cleaning, polyester and acrylic fibers are used, and are used after optimization by changing the shape such as loop shape and straight hair shape, and the hardness and thickness of the fibers. However, brush cleaning does not sufficiently remove fine toner, and is difficult to remove sufficiently, such as slipping between fibers. The same applies to magnetic brushes, and in this method, attempts have been made to remove electrostatically by applying an electric field, but this is sufficient to cause a phenomenon such as toner scattered by electrostatic force reattaching to the photoreceptor. Cleaning is difficult. Therefore, as the current cleaning means, blade cleaning using an elastic blade is mainly used from the standpoint of removal of residual toner, cost, and reduction in diameter. In blade cleaning, the photosensitive member surface layer slides in contact with the cleaning blade, toner, and the like, and therefore mechanical wear and scratches are likely to occur on the photosensitive member surface.

Due to the characteristics of the apparatus constituent members as described above, a physical external force is directly applied to the surface of the photoreceptor, and thus durability against them has been required.
Many research examples have been reported to improve these problems by increasing the hardness of the photoreceptor surface. For example, in Patent Document 1 and Patent Document 2, when a magnetic brush type is applied as a charger, magnetic particles are involuntarily transferred onto the photoconductor, and the particles are transferred to the photoconductor in the transfer unit or the cleaning unit. It has been proposed to increase the hardness of the surface layer of the photoreceptor in order to prevent scratching due to strong pressing. Further, Patent Document 3 proposes to increase the hardness of the photoconductor in order to suppress photoconductor surface wear when the blade-type cleaning method is applied.

  As specific means for increasing the surface hardness of the photoreceptor as described above, it has been proposed to use a crosslinkable material such as a thermosetting resin or a UV curable resin as a constituent component of the photoreceptor surface layer. . For example, Patent Document 4, Patent Document 5 and Patent Document 6 propose a technique for improving the wear resistance and scratch resistance of a surface layer by applying a thermosetting resin as a binder component of the surface layer. In Patent Document 7, Patent Document 8, Patent Document 9, and the like, it is proposed to improve wear resistance and scratch resistance by using a siloxane resin having a crosslinked structure as a charge transport material. Further, in Patent Document 10, Patent Document 11 and the like, in order to improve wear resistance and scratch resistance, both a binder and a charge transport material have a monomer having a carbon-carbon double bond, and a charge transport having a carbon-carbon double bond. Techniques using materials and binder resins have been reported.

  These crosslinkable materials form a tough film by cross-linking molecules with each other. The characteristics of the crosslinkable material depend on the crosslinking conditions (temperature conditions, humidity conditions, etc. for thermosetting resins, light wavelengths, illuminance, light quantity, temperature conditions, humidity conditions, etc. for photocurable resins). Different characteristics can be developed even with the same material.

  In particular, photocrosslinkable resins are very fast to be cured, and by changing the light irradiation conditions depending on the location, it is possible to obtain films with different characteristics even within the same plane. , Easy to express unique characteristics. Therefore, it is also used in industrial applications such as an adhesive tape having a partially different adhesive strength and an etching process used for fine processing. Moreover, the monomer used for a coating liquid has liquidity at normal temperature, and there are many things which can be coated only by it with a very low viscosity depending on material. Even when using relatively high viscosity monomers / oligomers to achieve the desired function, the viscosity can be adjusted with a small amount of solvent, reducing the power and man-hours required for the drying process, and the environment Benefits such as reduced load can also be obtained. On the other hand, when laminating a photo-curing resin that changes its properties by light irradiation, the light to be irradiated when curing the resin by devising the irradiation conditions and material prescriptions, etc. It is necessary to prevent the light from being transmitted through the layered light or to use light having a wavelength that is easily affected by the layered body.

  When such a photocurable material is applied to the photoreceptor surface layer, the charge generation material and charge transport material constituting the layered body (charge generation layer, charge transport layer, etc.) are easily damaged by light. The degree of cross-linking of the layer and the stability of the charge generation material and the charge transport material tend to have a reciprocal relationship. In other words, the hardness of the surface surface layer increases due to the polymerization reaction caused by light irradiation, but it may cause a decrease in electrical characteristics and a decrease in stability due to deterioration of the constituent materials of the charge transport layer and the charge generation layer as the laminate. Concerned. In addition, attention must be paid to a decrease in chargeability due to pre-exposure fatigue. It is known that pre-exposure fatigue is observed in a part of the high-sensitivity photoconductor, and is caused by the charge generation material absorbing light. This is because the surface charge is neutralized by the movement of the remaining carriers even if the charging operation is performed in the state where the charges generated by light absorption remain, and thus the surface potential is consumed until the remaining charges are consumed. As a result, the apparent charging property seems to be lowered.

  It is considered effective to cure the surface layer with a small amount of light exposure in order to make full use of such contradictory characteristics, but a simple reduction in light exposure causes a decrease in surface hardness due to poor curing. In addition, the electrical characteristics, wear resistance, scratch resistance, etc. are reduced due to the migration of low molecular components from the adjacent layers (referring to the photosensitive layer, charge transport layer, charge generation layer, etc. adjacent to the photoreceptor surface layer). cause. Furthermore, when curing is insufficient, safety problems such as mutagenicity and skin irritation due to unreacted functional groups arise. As another means, it is conceivable to select a photocurable material or an initiator that has a high reactivity as a material, or to crosslink at a relatively high temperature as a reaction condition. While sufficient crosslinking can be performed, defects such as cracks due to excessive shrinkage of the resin are likely to occur. For this reason, there is a concern that the wear durability is lowered and the electrical properties are lowered due to the brittleness of the surface layer.

  In order to give the electrophotographic photosensitive member a desired charge transport property, it is generally known that the surface layer may contain a compound having a charge transport structure. Many of the compounds themselves have light absorption characteristics from the ultraviolet region to the visible light short wavelength region, and when such compounds are used in combination with a photocurable resin, the ultraviolet light effective for curing does not sufficiently penetrate into the layer. There is a risk that poor curing occurs inside.

  As a countermeasure against such poor internal curing, a radical photopolymerization initiator (hereinafter also referred to as an initiator) to be used is one having absorption at a long wavelength, or as a compound having a charge transporting structure, the absorption wavelength is an initiator. The method of using what does not fog with the absorption wavelength of this is mentioned. However, when these measures are taken, the initiator and the compound having a charge transporting structure that can be used for the surface layer are limited, and it may be difficult to achieve both desired electrical characteristics and wear durability. .

As described above, when applying the photo-curing resin to the surface layer, there are many items to be noted, and selection of manufacturing conditions and the like is very difficult. However, the current situation is that the technique for using the photocurable resin has not been studied in detail.
JP 2001-125286 A JP 2001-324857 A JP 2003-98708 A JP-A-5-181299 JP 2002-6526 A JP 2002-82465 A JP 2000-284514 A JP 2000-284515 A JP 2001-194413 A Japanese Patent No. 3194392 Japanese Patent No. 3286704

  The present invention has been made in view of the above-described problems of the prior art, and in the case of using a photocurable material to improve the abrasion resistance and scratch resistance of the photoreceptor, the curing failure, excessive shrinkage, and the adjacent layer Defects related to the output image quality of the image forming device, such as wear and scratches due to repeated use of the photoconductor, without causing physical problems such as subsequent low molecular components, and obtaining a film with the desired surface hardness Another object of the present invention is to provide an electrophotographic photosensitive member having excellent electric characteristics by preventing deterioration of the material constituting the photosensitive member due to light irradiated on the photosensitive member during production.

  As a result of intensive research to achieve the above-mentioned objectives, the present researchers have at least a photosensitive layer and a surface layer in order on a conductive support, and in the case of applying a photocurable material as the surface layer, the surface layer And at least one sensitizing dye and a polymerization initiator, and the absorption edge wavelength λe (nm) on the long wavelength side in the optical absorption spectrum of the compound having the charge transport structure is less than 480 nm, The surface layer can be uniformly cured by a method in which the maximum absorption wavelength λmax (nm) of the sensitizing dye is not less than the absorption edge wavelength λe (nm) on the long wavelength side of the compound having a charge transport structure and not more than 500 nm. I found what I could achieve. Further, the transmittance of the surface layer to which the sensitizing dye is added is set to 60% or less in the wavelength region of the absorption edge wavelength λe (nm) on the long wavelength side of the compound having a charge transporting structure to 480 nm or less. It has been found that the influence on the photosensitive layer by light used for layer curing can be reduced. As a result, the inside of the surface layer can be uniformly cured, and the deterioration of the constituent components of the photosensitive layer due to the light used to cure the surface layer can be suppressed. It is possible to maximize the characteristics of a transport material and a material having contradictory properties such as a surface layer constituting material that requires light irradiation for crosslinking. As a result, it is possible to extremely reduce the occurrence of wear and scratches on the surface layer of the photoreceptor even by repeated use, and to prevent the occurrence of defects related to the output image quality of the image forming apparatus by suppressing the deterioration of the electrical characteristics during manufacture. An electrophotographic photoreceptor can be provided.

  That is, the electrophotographic photoreceptor according to claim 1 of the present invention has at least a photosensitive layer and a surface layer in this order on a conductive support, and the surface layer has at least a charge transporting structure and a charge transporting structure. In an electrophotographic photosensitive member formed by crosslinking a radically polymerizable monomer having no photochemical energy by means of light energy irradiation, the surface layer is crosslinked using at least one sensitizing dye and a polymerization initiator. The absorption edge wavelength λe (nm) on the long wavelength side in the optical absorption spectrum of the compound having the charge transporting structure is less than 480 nm, and the maximum absorption wavelength λmax (nm) of the sensitizing dye is λe (nm) or more and 500 nm. It is characterized by the following. According to the present invention, even when the surface layer contains a compound having a charge transporting structure that absorbs ultraviolet light to visible short-wavelength light, it can be uniformly cured to the depth of the surface layer. Thus, it is possible to provide an excellent electrophotographic photosensitive member that is excellent in wear durability over a long period of time and has few defects related to image quality.

The electrophotographic photoreceptor according to claim 2 of the present invention is characterized in that the transmittance of the surface layer is 60% or less in at least a wavelength region of λe (nm) or more and 480 nm or less. Is.
The electrophotographic photosensitive member according to claim 3 of the present invention is characterized in that the sensitizing dye has a λe (nm) and a molar extinction coefficient at 480 nm of 10,000 l / mol · cm or more. belongs to. According to the present invention, it is possible to provide an electrophotographic photosensitive member that can suppress deterioration of the constituent components of the photosensitive layer due to light required for curing the surface layer and has excellent electrical characteristics.

The electrophotographic photoreceptor according to claim 4 of the present invention is characterized in that the compound having a charge transporting structure used for the surface layer has a radical polymerizable functional group. belongs to.
The electrophotographic photosensitive member according to claim 5 of the present invention is characterized in that the radical polymerizable functional group of the compound having the charge transporting structure is an acryloyloxy group or a methacryloyloxy group. Is. According to the present invention, a compound having a charge transporting structure can be incorporated into a crosslinked network to improve the crosslinking density. Accordingly, it is possible to provide an electrophotographic photosensitive member that has extremely excellent wear durability and has few defects relating to image quality over a long period of time.

The electrophotographic photoreceptor according to claim 6 of the present invention is characterized in that the charge transporting structure of the compound having the charge transporting structure is a triarylamine structure. belongs to. According to the present invention, it is possible to provide an electrophotographic photoreceptor having a surface layer with high charge transportability and excellent electrical characteristics.
The electrophotographic photosensitive member according to claim 7 of the present invention is characterized in that the compound having the charge transporting structure has one radical polymerizable functional group. belongs to. According to the present invention, it is possible to reduce internal stress due to suppression of shrinkage of the surface layer during photocuring, generation of cracks during surface layer formation or use inside the image forming apparatus, surface layer / photosensitivity. It is possible to provide an electrophotographic photosensitive member that hardly causes delamination between layers and has excellent wear durability over a long period of time.

The electrophotographic photoreceptor according to claim 8 of the present invention is characterized in that the radical polymerizable functional group of the radical polymerizable monomer having no charge transporting structure is an acryloyloxy group or a methacryloyloxy group. It is a thing in any one of 1 thru | or 7.
According to a ninth aspect of the present invention, there is provided an image forming method according to any one of the first to eighth aspects, wherein the electrophotographic photosensitive member is charged at least by the charging process and the charging process. A latent image forming process for forming an electrostatic latent image on the surface of the electrophotographic photosensitive member, a developing process for attaching toner to the electrostatic latent image formed by the latent image forming process, and a toner image formed by the developing process. It is characterized in that a transfer process for transferring to a transfer object is repeated.

An image forming apparatus according to a tenth aspect of the present invention is an electrophotographic photosensitive member according to any one of the first to eighth aspects, a charger for charging at least the electrophotographic photosensitive member, and an electron charged by the charger. A latent image forming device for forming an electrostatic latent image on the surface of a photographic photosensitive member, a developing device for attaching toner to the electrostatic latent image formed by the latent image forming device, and a toner image formed by the developing device to be transferred And a transfer device for transferring to the body.
A process cartridge for an image forming apparatus according to an eleventh aspect of the present invention is an electrophotographic photosensitive member according to any one of the first to eighth aspects, a charger for charging at least the electrophotographic photosensitive member, and a charging device for charging. A latent image forming device for forming an electrostatic latent image on the surface of the electrophotographic photosensitive member, a developer for attaching toner to the electrostatic latent image formed by the latent image forming device, and a toner image formed by the developing device And a transfer device that transfers the toner to the transfer material, and a cleaning device that removes toner remaining on the surface of the electrophotographic photosensitive member after transfer from the surface of the electrophotographic photosensitive member, The image forming apparatus main body is detachable. According to the present invention, the mechanical durability is excellent, and defects relating to the output image quality of the image forming apparatus such as wear and scratches due to repeated use of the photoreceptor do not occur, and a high-quality image can be formed over a long period of time. An image forming method, an image forming apparatus, and a process cartridge for the image forming apparatus are provided.

  According to the present invention, even when the surface layer contains a compound having a charge transporting structure that absorbs ultraviolet light to visible short-wavelength light, it can be uniformly cured to the depth of the surface layer. Thus, it is possible to provide an excellent electrophotographic photosensitive member that is excellent in wear durability over a long period of time and has few defects related to image quality. Furthermore, it is possible to provide an electrophotographic photosensitive member that can suppress deterioration of the constituent components of the photosensitive layer due to light required for curing the surface layer and has excellent electrical characteristics.

  In an electrophotographic process, a blade cleaning system is often used as a means for cleaning toner on a photoreceptor. This is a method of mechanically removing the toner by pressing an elastic blade against the photoconductor, and there are advantages such as a reduction in size due to a simple structure and a low cost. However, since this cleaning method applies mechanical stress to the photoconductor, the photoconductor is worn and scratched by repeated use. Therefore, it is often difficult to provide a stable output image over a long period of time.

  In order to suppress the occurrence of wear and scratches due to repeated use, it is effective that the mechanical strength represented by the hardness and elastic work rate of the surface of the photoconductor is large. Various methods and materials are used to increase these characteristics. Has been developed. In order to increase the mechanical strength, it is generally known to use a crosslinkable material in which molecules are bonded to each other. The crosslinkable material can express various properties by selecting the functional group structure, molecular structure, number of functional groups, etc., and not only the desired mechanical strength but also the electrical properties required for electrophotographic photoreceptors. Recently, it has been attracting attention as a material for electrophotographic photoreceptors because it allows molecular design that also takes into account the physical characteristics.

  By using a crosslinkable material for the surface layer of the photoreceptor, it is possible to dramatically improve the mechanical durability, which can greatly reduce image defects caused by wear and scratches. However, it is necessary to apply energy such as heat and light at the time of cross-linking, so that the material constituting the photosensitive layer is deteriorated, which may cause a decrease in electrical characteristics and a decrease in oxidizing gas durability. In addition, it is generally known that it is effective to add a compound having a charge transporting structure to the surface layer in order to give an excellent charge transporting property to the photoreceptor, but it has a charge transporting structure. When the compound itself has absorption in the short wavelength range from ultraviolet light to visible light, when used in combination with a photo-curing resin, there is a problem in terms of wear durability deterioration due to poor curing at the deep layer and safety in use. There is.

  The present invention has been made to remedy these problems. The optical layer of the compound having at least one sensitizing dye and a polymerization initiator in the surface layer and having the charge transporting structure is provided. The absorption wavelength λe (nm) on the long wavelength side in the absorption spectrum is less than 480 nm, and the maximum absorption wavelength λmax of the sensitizing dye is not less than the absorption wavelength λe (nm) on the long wavelength side of the compound having a charge transporting structure. It was found that by setting the thickness to 500 nm or less, uniform curing can be performed up to the deep part of the surface layer, and it is possible to provide an electrophotographic photosensitive member that is less prone to image-related defects over a long period of time. Further, by setting the transmittance of the surface layer containing the sensitizing dye to λe (nm) or more and 480 nm or less to 60% or less, the influence on the photosensitive layer due to the light required for curing the surface layer is suppressed, and excellent electrical properties are obtained. The inventors have found that an electrophotographic photosensitive member having characteristics can be provided, and have reached the present invention.

Details of the present invention will be described below.
<Configuration of electrophotographic photosensitive member>
The photoreceptor of this embodiment is a laminate having at least a photosensitive layer and a surface layer in this order on a conductive support. The photosensitive layer may have a single layer structure or a multilayer structure as long as it has a charge generation function and a charge transport function. An example of the embodiment will be described with reference to FIGS.
The cross-sectional view of the electrophotographic photosensitive member shown in FIG. 1 is an example in which the photosensitive layer is a single layer. On the conductive support 31, a photosensitive layer 34 mainly composed of a charge generating substance and a charge transporting substance, and A surface layer 35 is provided. The surface layer 35 described here is a crosslinkable surface layer described below.

  The cross-sectional views of the electrophotographic photosensitive member shown in FIG. 2 and FIG. 3 are examples in the case where the photosensitive layer is a laminate, and a charge generating layer having a charge generating function and a charge having a charge transporting function on a conductive support. The transport layer is separated and laminated. In the case of adopting this embodiment, as shown in the figure, the order of stacking the charge generation layer and the charge transport layer on the conductive support is not particularly limited, and can be properly used according to the application. A surface layer is laminated on the surface.

<Description of dye>
It is generally known that it is preferable to add a compound having a charge transporting structure to the surface layer in order to give the photosensitive layer excellent charge transporting functional characteristics. Therefore, when such a compound is used in combination with a photocurable resin, there is a concern about poor curing in the deep layer.
In the present invention, since the surface layer is crosslinked and cured using a sensitizing dye and a polymerization initiator, the sensitizing dye can sensitize the polymerization initiator and accelerate the curing reaction, so that only the polymerization initiator is used. It can be made to harden even to the deep part of the layer from the case where is used.
In addition, by adding a sensitizing dye to the surface layer, the sensitizing dye absorbs light required for curing, so that the surface layer can have a light-shielding function and suppress the influence of light on the photosensitive layer. Can do.

The sensitizing dye described in the present invention is a transition to an excited singlet state or an excited triplet state by light energy absorption, causing energy or electron transfer to the initiator, so that the initiator is originally absorbed. Even when light in a wavelength region that does not exist is irradiated, a curing reaction can be caused.
The sensitizing dye that can be used in the present invention is a compound that can sensitize the spectral wavelength of the polymerization initiator by the mechanism described above, and the maximum absorption wavelength of the sensitizing dye is λmax (nm), and the electrons used for the surface layer. When the absorption edge λe (nm) on the long wavelength side calculated from the optical spectrum of the compound having a transporting structure is used, the relationship between both wavelengths is
λe <λmax
If it is, it will not specifically limit. If this relationship is not satisfied, there are many portions where the absorption wavelength region of the sensitizing dye and the absorption wavelength region of the compound having a charge transporting structure are covered, and curing due to the inability to efficiently perform dye sensitization inside the surface layer Defects may occur.

  In addition, since the formation of an electrostatic latent image in an electrophotographic process is performed by irradiating laser light, it is not preferable to use a sensitizing dye that shields the laser light. As laser light wavelengths used in recent image forming apparatuses, those having a wavelength of 655 nm and 780 nm are often used. Therefore, the maximum absorption wavelength λmax is 500 nm or less, preferably 480 nm or less.

  In the present invention, a generally used compound can be used as long as it is a sensitizing dye that satisfies the above-described conditions. For example, cyanine dye, squarylium cyanine dye, styryl dye, pyrylium dye, merocyanine dye, arylidene dye, oxonol dye, azurenium dye, coumarin dye, ketocoumarin dye, styrylcoumarin dye, pyran dye, xanthene dye, thioxanthene dye, phenothiazine dye Phenoxazine dyes, phenazine dyes, phthalocyanine dyes, azaporphyrin dyes, porphyrin dyes, fused aromatic dyes, perylene dyes, azomethine dyes, anthraquinone dyes, metal complex dyes, metallocene dyes, and more preferably cyanine Dye, squarylium cyanine dye, pyrylium dye, merocyanine dye, oxonol dye, coumarin dye, ketocoumarin dye, styrylcoumarin dye, pyran dye, xanthene Arsenide, thioxanthene dyes, condensed aromatic dyes, metal complex dyes, metallocene dyes. In addition, “Dye Handbook” (Shin Okawara et al. Kodansha 1986), “Chemicals of Functional Dye” (Shin Okawara et al. CMC 1981), “Special Functional Materials” (Chemical Icmori Tadasaburo et al. CMC 1986) The dyes and dyes described in (Year) can also be used as the sensitizing dye of the present invention. These sensitizing dyes may be used alone, or two or more sensitizing dyes may be used in accordance with the emission wavelength of the tube used for curing.

A method for measuring the maximum absorption wavelength λmax of these sensitizing dyes will be described.
The maximum absorption wavelength λmax of the sensitizing dye defined in the present invention is calculated from the relationship between the absorbance vs wavelength (absorption characteristic) measured using a spectrophotometer for a solution in which the sensitizing dye is dissolved in an appropriate solvent. An example of measurement results of absorbance vs wavelength is shown in FIG. The maximum absorption wavelength indicates the wavelength at which the absorbance is maximum, and corresponds to the wavelength at point a in FIG. At this time, it is preferable to adjust the solution so that the absorbance at the maximum absorption wavelength falls within a range of 0.3 to 0.7. When the absorbance is 0.7 or more, or 0.3 or less, the absorbance is maximized. This is not preferable because the dots are difficult to read. In the present invention, the absorbance vs wavelength was measured as follows.

<< Solvent >> Tetrahydrofuran << Concentration >> The concentration should be adjusted so that the absorbance at the wavelength of the maximum spherical species falls within the range of 0.3 to 0.7.
Adjustment << Apparatus >> Spectrophotometer UV-3100 (manufactured by Shimadzu Corporation)
<Conditions> Measurement mode: Absorbance measurement
Measurement wavelength: 300 nm to 700 nm

が成り立つと考えられている（ここでＢは定数を示す）。従って、吸収スペクトルを測定し、そこから（αｈν）の０．５乗に対してｈνをプロットし、直線区間を外挿したα＝０におけるｈνの値が遷移エネルギーＥ_０となり、その波長換算値

が本発明で用いる吸収端波長となる（但し、ｃは光速を表す）。 Next, a method for measuring the optical absorption edge λe (nm) of a compound having a charge transporting structure will be described.
The absorption edge wavelength λe (nm) of the compound having a charge transport structure defined in the present invention is the absorption edge wavelength on the long wavelength side, and is a wavelength converted value of the transition energy of HOMO-LUMO unique to each material. It shall be equivalent. That is, generally in the region of relatively large absorption near the optical absorption edge on the long wavelength side, the absorption coefficient α and the light energy hν (where h is the Planck constant, ν is the wave number) and the band cap energy E ₀ are between The following formula,

(Where B is a constant). Therefore, the absorption spectrum is measured, hν is plotted against (αhν) to the 0.5th power, and hν value at α = 0 extrapolating the straight line section becomes the transition energy E ₀ , and its wavelength conversion value

Is the absorption edge wavelength used in the present invention (where c represents the speed of light).

  When calculating the absorption edge wavelength by the above calculation method, it is necessary to obtain the relationship between the absorbance vs wavelength (absorption characteristics) of each material. The method for measuring light absorption characteristics is not particularly limited, but it is very difficult to calculate λe (nm) when the absorption of the target material is small (for example, the charge transporting material has a low concentration relative to the bulk, etc.) Therefore, the absorbance near the optical absorption edge on the long wavelength side needs to be 1 or more and less than 3.

Next, the amount of sensitizing dye added to the surface layer will be described.
As described above, when a photocurable resin is applied as the surface layer of the electrophotographic photosensitive member, the electrical characteristics of the photosensitive member may be deteriorated by light required for curing. In this case, a device for reducing the amount of light transmitted to the photosensitive layer is required. In the present invention, by incorporating a sensitizing dye into the surface layer, the sensitizing dye absorbs light required for curing and can accelerate curing of the surface layer, and at the same time, the sensitizing dye absorbs light required for curing. By doing so, the surface layer can have a light shielding function, and the influence of light on the photosensitive layer can also be suppressed.

  Since the surface layer contains a compound having a charge transporting structure, light below the absorption edge λe (nm) on the long wavelength side of the compound having a charge transporting structure is not easily transmitted to the photosensitive layer. Therefore, it is preferable to design the light-shielding function by the sensitizing dye so as to absorb light having a wavelength of λe (nm) or more. In the present invention, when the surface layer has absorption in the wavelength region of λe (nm) or more and 480 nm or less, the influence of light on the photosensitive layer can be reduced, and the latent image writing laser light in the electrophotographic imaging process can be reduced. It was confirmed that there was no shielding. For light longer than the wavelength specified in the present invention, it is generally cut by selecting a tube of a light irradiating device or using a wavelength cut filter, but also in the present invention such a long wavelength cut. By using the technique together, the influence on the photosensitive layer can be further reduced.

  In order to protect the photosensitive layer from the light required for curing, the transmittance of the surface layer in the above-mentioned wavelength region is at least 60% or less, preferably 50% or less. The lower limit of the transmittance is not particularly limited from the viewpoint of protecting the irradiated light to the photosensitive layer, but when the transmittance of the surface layer is small, the light that can be absorbed by the sensitizing dye in the deep portion of the surface layer is reduced, and the sensitizing action. There is a risk of poor curing due to a decrease in. Therefore, the transmittance of the surface layer is preferably at least 10% or more. The transmittance of the surface layer can be adjusted by the addition amount of the sensitizing dye.

  The addition amount cannot be generally defined by the molecular weight or molar extinction coefficient of the sensitizing dye, but is preferably used in the range of 0.01% to 25% by weight with respect to the initiator. Adding more than 25% by weight with respect to the initiator is not preferable because it may cause a decrease in hardness or poor curing due to a decrease in the functional group density of the surface layer. Moreover, it is thought that it may cause problems such as poor internal curing due to a decrease in surface layer transmittance, which is also not preferable. Further, when the amount is less than 0.01% by weight with respect to the initiator, it is not preferable because neither the sensitizing action nor the light shielding function is sufficient, and the surface layer may be poorly cured or the photosensitive layer may be deteriorated by light. .

  As will be described later, it is preferable that the film thickness of the surface layer is 2 μm or more and 20 μm or less in order to give the photoreceptor the desired wear durability and electrical characteristics. In order to add a sensitizing dye to such a surface layer to sufficiently provide a light-shielding function, and to prevent poor curing and deterioration of electrical characteristics due to excessive addition of the sensitizing dye, λe (nm) of the sensitizing dye to be added ) And the molar extinction coefficient at 480 nm is preferably 10000 l / mol · cm or more, more preferably 15000 l / mol · cm or more. When the molar extinction coefficient is less than 10,000 l / mol · cm, the light shielding function in the surface layer is not sufficient, and the light irradiation required for curing causes a decrease in electrical characteristics due to deterioration of the constituent components of the photosensitive layer, which is not preferable. Although it is possible to reduce the transmittance by excessively adding a sensitizing dye, in that case, the functional group density of the surface layer is reduced as described above, and therefore there are problems such as a decrease in hardness of the surface layer and poor curing. Since it occurs, it is not preferable.

As a method for measuring the transmittance of the surface layer, a method was adopted in which the surface layer was produced with a predetermined thickness on a transparent substrate and the transmittance of the surface layer was measured using a spectrophotometer. As the transparent substrate, a compound that transmits light having a wavelength longer than the absorption edge wavelength λe (nm) on the long wavelength side of the compound having a charge transporting structure may be selected. Moreover, as a transparent substrate, what is smooth and has solvent resistance is preferable. For example, a quartz plate, a PET film, and the like can be mentioned. However, the material of the transparent substrate is not particularly limited as long as a suitable base material for film formation is selected. The transmittance of the surface layer / transparent substrate thus prepared is measured with a spectrophotometer, and the transmittance of the surface layer is obtained by subtracting the transmittance of the transparent substrate alone. In the present invention, the transmittance was measured as follows.
<< Substrate >> 2 mm thick quartz plate << Apparatus >> Spectrophotometer UV-3100 (manufactured by Shimadzu Corporation)
<Conditions> Measurement mode: Transmittance measurement
Measurement wavelength: 300 nm to 700 nm

<About the surface layer>
Next, the constituent material of the surface layer of this invention is demonstrated.
<Regarding radical polymerizable monomer having no charge transport structure>
The radical polymerizable monomer having no charge transport structure used in the present invention is a hole transport structure such as triarylamine, hydrazone, pyrazoline, carbazole, such as condensed polycyclic quinone, diphenoquinone, cyano group or nitro group. A compound having no electron transport structure such as an electron-withdrawing aromatic ring and having a radical polymerizable functional group. The radical polymerizable functional group is not particularly limited as long as it has a carbon-carbon double bond and can be radically polymerized.

〔ただし、式中、Ｘ₁は、置換基を有していてもよいフェニレン基、ナフチレン基等のアリーレン基、置換基を有していてもよいアルケニレン基、−ＣＯ−基、−ＣＯＯ−基、−ＣＯＮ（Ｒ₁₀）−基（Ｒ₁₀は、水素、メチル基、エチル基等のアルキル基、ベンジル基、ナフチルメチル基、フェネチル基等のアラルキル基、フェニル基、ナフチル基等のアリール基を表す。）、または−Ｓ−基を表わす。〕
これらの置換基を具体的に例示すると、ビニル基、スチリル基、２−メチル−１，３−ブタジエニル基、ビニルカルボニル基、アクリロイルオキシ基、アクリロイルアミド基、ビニルチオエーテル基等が挙げられる。 Examples of the radical polymerizable functional group include a 1-substituted ethylene functional group and a 1,1-substituted ethylene functional group shown below.
(1) Examples of the 1-substituted ethylene functional group include functional groups represented by the following general formula (1).

[Wherein, X ₁ is an arylene group such as a phenylene group or a naphthylene group optionally having a substituent, an alkenylene group optionally having a substituent, a —CO— group, a —COO— group. , —CON (R ₁₀ ) — group (R ₁₀ represents an alkyl group such as hydrogen, methyl group or ethyl group, an aralkyl group such as benzyl group, naphthylmethyl group or phenethyl group, or an aryl group such as phenyl group or naphthyl group. Or -S- group. ]
Specific examples of these substituents include a vinyl group, a styryl group, a 2-methyl-1,3-butadienyl group, a vinylcarbonyl group, an acryloyloxy group, an acryloylamide group, and a vinyl thioether group.

〔ただし、式中、Ｙは、置換基を有していてもよいアルキル基、置換基を有していてもよいアラルキル基、置換基を有していてもよいフェニル基、ナフチル基等のアリール基、ハロゲン原子、シアノ基、ニトロ基、メトキシ基あるいはエトキシ基等のアルコキシ基、−ＣＯＯＲ₁₁基（Ｒ₁₁は、水素原子、置換基を有していてもよいメチル基、エチル基等のアルキル基、置換基を有していてもよいベンジル、フェネチル基等のアラルキル基、置換基を有していてもよいフェニル基、ナフチル基等のアリール基を表す。）、または−ＣＯＮＲ₁₂Ｒ₁₃（Ｒ₁₂およびＲ₁₃は、水素原子、置換基を有していてもよいメチル基、エチル基等のアルキル基、置換基を有していてもよいベンジル基、ナフチルメチル基、あるいはフェネチル基等のアラルキル基、または置換基を有していてもよいフェニル基、ナフチル基等のアリール基を表わし、互いに同一または異なっていてもよい。）、
また、Ｘ₂は上記式（１）のＸ₁と同一の置換基及び単結合、アルキレン基を表わす。ただし、Ｙ、Ｘ₂の少なくとも何れか一方がオキシカルボニル基、シアノ基、アルケニレン基、及び芳香族環である。〕 (2) Examples of the 1,1-substituted ethylene functional group include functional groups represented by the following general formula (2).

[Wherein 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, an aryl such as a naphthyl group, etc. 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 alkyl such as an optionally substituted methyl group or ethyl group) A benzyl group optionally having a substituent, an aralkyl group such as a phenethyl group, an aryl group such as a phenyl group and a naphthyl group optionally having a substituent), or -CONR ₁₂ R ₁₃ ( R ₁₂ and R ₁₃ are each a hydrogen atom, an optionally substituted methyl group, an alkyl group such as an ethyl group, an optionally substituted benzyl group, a naphthylmethyl group, or a phenethyl group. Aralkyl , Or may have a substituent phenyl group, an aryl group such as a naphthyl group, which may be the same or different from each other.)
X ₂ represents the same substituent, single bond, and alkylene group as X _{1 in the} above formula (1). However, at least one of Y and X ₂ is an oxycarbonyl group, a cyano group, an alkenylene group, or 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.

  In the present invention, the number of functional groups of the radical polymerizable monomer is not particularly limited, but in order to give the surface layer wear resistance, at least one radical polymerizable monomer having three or more radical polymerizable functional groups is used. It is preferable to use it. When only monofunctional and bifunctional radically polymerizable monomers are used, the cross-linking bond in the cross-linked surface layer may become dilute, and it may be difficult to achieve a dramatic improvement in wear resistance. However, when using only a trifunctional or higher-functional radical polymerizable monomer, defects such as a decrease in surface smoothness due to an increase in the viscosity of the coating liquid and a crack due to volume shrinkage during the curing reaction may occur. One or more kinds of radically polymerizable monomers and one or more radically polymerizable oligomers are used in combination for the purpose of adjusting the viscosity of the coating liquid, maintaining the surface smoothness of the surface layer, preventing cracks due to crosslinking shrinkage, and reducing the surface free energy. Also good.

  Examples of these radical polymerizable monomers include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, 2-ethylhexyl carbitol acrylate, 3-methoxybutyl acrylate, benzyl acrylate, and cyclohexyl. Acrylate, isoamyl acrylate, isobutyl acrylate, methoxytriethylene glycol acrylate, phenoxytetraethylene glycol acrylate, cetyl acrylate, isostearyl acrylate, stearyl acrylate, styrene monomer, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate 1,4-butanediol dimethacrylate, 1,6- Xanthdiol diacrylate, 1,6-hexanediol dimethacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, EO-modified bisphenol A diacrylate, EO-modified bisphenol F diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate ( TMPTA), trimethylolpropane trimethacrylate, trimethylolpropane alkylene modified triacrylate, trimethylolpropane ethyleneoxy modified (hereinafter EO modified) triacrylate, trimethylolpropane propyleneoxy modified (hereinafter PO modified) triacrylate, trimethylolpropane caprolactone modified Triacrylate, trimethylolpropane alkylene modified trimer Chryrate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol triacrylate, glycerol epichlorohydrin modified (ECH modified) triacrylate, glycerol EO modified triacrylate, glycerol PO modified triacrylate, tris (acryloxyethyl) Isocyanurate, dipentaerythritol hexaacrylate (DPHA), dipentaerythritol caprolactone-modified hexaacrylate, dipentaerythritol hydroxypentaacrylate, alkylated dipentaerythritol pentaacrylate, alkylated dipentaerythritol tetraacrylate, alkylated dipentaerythritol triacrylate , Dimethylol propane tet Examples include laacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, phosphoric acid EO-modified triacrylate, 2,2,5,5-tetrahydroxymethylcyclopentanone tetraacrylate, and the like in the present invention. It is not limited to.

<About compounds having a charge transporting structure>
The compound having a charge transporting structure described in the present invention (hereinafter also referred to as a charge transporting material) may or may not have a radical polymerizable functional group in the structure. However, in order to impart wear durability to the surface layer, it is preferable to have a radical polymerizable functional group.
Here, the charge transporting material having no radically polymerizable functional group is a substance having charge transporting performance, and specifically includes a hole transporting substance and an electron transporting substance as shown below.
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-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide and diphenoquinone derivatives. These electron transport materials can be used alone or as a mixture of two or more.

  Examples of hole transport materials include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazolines Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, bisstilbene derivatives, enamine derivatives, etc. Other known materials may be used. These charge transport materials may be used alone or in combination of two or more.

  The charge transporting material having a radical polymerizable functional group is, for example, a hole transporting structure such as triarylamine, hydrazone, pyrazoline, and carbazole, for example, an electron having a condensed polycyclic quinone, diphenoquinone, a cyano group, or a nitro group. It refers to a compound having an electron transport structure such as an attractive aromatic ring and having a radical polymerizable functional group. Examples of the radical polymerizable functional group include those shown in the above radical polymerizable monomer, and acryloyloxy group and methacryloyloxy group are particularly useful.

  The number of functional groups of the charge transporting material having a radical polymerizable functional group is not particularly limited. In order to give the surface layer excellent wear durability, a charge transporting material having two or more functions may be used. However, the surface layer may be cracked due to cross-linking shrinkage during curing, or residual stress inside the film may be caused. In addition, the film is easily peeled off from the surface layer during use. In addition, in terms of electrostatic characteristics, when a bifunctional or higher functional charge transporting compound is used, it is fixed in the crosslinked structure with a plurality of bonds, so that the intermediate structure (cation radical) during charge transport is stably maintained. In other words, the sensitivity is lowered due to charge trapping, and the residual potential is likely to increase. Such deterioration of the electrical characteristics appears as an image such as a decrease in image density and thinning of characters. For this reason, the charge transporting material having a radical polymerizable group uses a charge transporting material having a monofunctional radical polymerizable group and is fixed in a pendant shape between crosslinks, thereby causing cracks and scratches. And stabilization of electrostatic characteristics.

（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、−ＣＯＯＲ₆（Ｒ₆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ＣＯＮＲ₇Ｒ₈（Ｒ₇及びＲ₈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。） A triarylamine structure is highly effective as a charge transporting structure. Moreover, what has one functional group is preferable, and when a compound represented by the structure of the following general formula (3) or (4) is used, electrical characteristics such as sensitivity and residual potential are favorably sustained. .

(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 ₆ (R ₆ 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 ₇ R ₈ (R ₇ and R ₈ 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 (3) and (4) are shown below.
In the general formulas (3) and (4), 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 of R _1, particularly preferred are a hydrogen atom, a methyl group.

Ar ₃ and Ar ₄ represent substituted or unsubstituted aryl, and in the present invention, the aryl group includes a condensed polycyclic hydrocarbon group, a non-fused cyclic hydrocarbon group and a heterocyclic group, The group of is mentioned.
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 groups, preferably C ₁ -C _12, especially C ₁ -C ₈ , more preferably C ₁ -C ₄ linear or branched alkyl groups, and these alkyl groups further contain fluorine atoms , a hydroxyl group, a cyano group, an alkoxy group of C ₁ -C _4, a phenyl group or a halogen atom, which may have a phenyl group substituted by an alkoxy group C ₁ -C ₄ alkyl or C ₁ -C ₄ Good. 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 C ₁ -C ₄ alkoxy groups, C ₁ -C good .R ₃ and R ₄ may contain as alkyl group or a halogen atom substituents ₄ may be linked to form a ring.)
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, an alkoxy group of C ₁ -C _4, a phenyl group or a halogen atom, a phenyl group substituted with an alkyl group or a C ₁ -C ₄ alkoxy group C ₁ -C ₄ It may be. 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, alkylene ether group alkylene group is hydroxyl group, methyl group, ethyl group, etc. You may have the substituent of.

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 1-3.

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

（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 radically polymerizable compound having a monofunctional charge transporting structure of the present invention is more preferably a compound having the structure of the following general formula (5).

(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 of the above general formulas (3) and (4), particularly (5) used in the present invention is polymerized by releasing the carbon-carbon double bond on both sides. Therefore, it does not become a terminal structure, but is incorporated in a chain polymer and cross-linked by polymerization with a radical polymerizable monomer that does not have a charge transporting structure. And present in a cross-linked chain between the main chain and the main chain (this cross-linked chain includes an intermolecular cross-linked chain between one polymer and another polymer, and a main chain in a folded state in one polymer. There is an intramolecular cross-linked chain in which a site with a chain and another site derived from a polymerized monomer at a position away from this in the main chain are cross-linked). Even when present in the cross-linked chain, the triarylamine structure suspended from the chain portion Has at least three aryl groups arranged radially from the nitrogen atom and is bulky, but is not directly bonded to the chain part and is suspended from the chain part via a carbonyl group or the like. Since these triarylamine structures are fixed in a flexible manner in the positioning, they can be arranged adjacent to each other in the polymer, so that there is little structural distortion in the molecule, and electrophotography In the case of the surface layer of the photoreceptor, it is presumed that an intramolecular structure that is relatively free from interruption of the charge transport path can be adopted.

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

<Initiator>
The surface layer of the present invention is a crosslinked surface layer obtained by simultaneously curing at least a radically polymerizable monomer having no charge transporting structure and a compound having a charge transporting structure, so that the crosslinking reaction can proceed efficiently. A polymerization initiator is added to the crosslinked surface layer.

Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2- Acetophenone-based or ketal-based photopolymerization initiators such as methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, Benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether Benzoin ether photopolymerization initiators such as benzoin isopropyl ether, benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoylphenyl ether, acrylated benzophenone, Benzophenone photopolymerization initiators such as 1,4-benzoylbenzene, thioxanthones such as 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone Photopolymerization initiator, bis (cyclopentadienyl) -di-chloro-titanium, bis (cyclopentadienyl) -di-phenyl-titanium, bis (cyclopentadienyl) -bis ( , 3,4,5,6 pentafluorophenyl) titanium, bis (cyclopentadienyl) -bis (2,6-difluoro-3- (pyrrol-1-yl) phenyl) titanium, etc. Other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenyl Examples include phosphine oxide, bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10-phenanthrene, acridine compounds, triazine compounds, and imidazole compounds. Be . Moreover, what has a photopolymerization acceleration effect can also be used individually or in combination with the said photoinitiator. Examples thereof include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, 4,4′-dimethylaminobenzophenone, and the like.
These polymerization initiators may be used alone or in combination of two or more. Content of a polymerization initiator is 0.01-40 weight part with respect to 100 weight part of compounds which have radical polymerizability, Preferably it is 0.1-25 weight part.

<About additives>
Furthermore, the coating liquid of the present invention can contain additives such as various plasticizers (for the purpose of stress relaxation and adhesion improvement) and leveling agents as necessary. 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. 20 parts by weight or less, preferably 10 parts by weight 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 parts by weight or less is appropriate.

<About coating methods and solvents>
When the radically polymerizable monomer having no charge transporting structure is a liquid, the surface layer coating liquid of the present invention can be applied by dissolving other components in the liquid. 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, and 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. Coating can be done using dip coating, spray coating, bead coating, ring coating, etc., but spray coating is the best method for forming the surface layer without eroding the photosensitive layer. is there.

<About forming method>
In this invention, after apply | coating this coating liquid, a surface layer is hardened by giving energy from the outside. As the external energy used at this time, light energy is mainly used.

As the light energy, a light source such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc metal halide lamp or the like, preferably a radical polymerizable monomer having no charge transporting structure to be used, A compound having a charge transporting structure, a photopolymerization initiator used in combination, and an absorption characteristic of a sensitizing dye are preferably selected. The emission intensity of light source used, it is preferable generally is exposed with 365nm illumination of 50mW / cm ² ~2000mW / cm ² and wavelength as a reference. Moreover, when the illuminance measurement in the vicinity of the maximum emission wavelength is possible, it is more preferable to expose in the illuminance range. When the illuminance is low, the time required for curing increases, which is not preferable from the viewpoint of productivity. On the other hand, when the illuminance is high, curing shrinkage is likely to occur, and the surface may have a skin-like defect or crack, or may peel at the interface with the adjacent layer.

  During light irradiation, the temperature of the surface layer of the photoreceptor rises due to the influence of heat rays generated from the light source. If the surface temperature of the photoconductor rises too much, curing shrinkage of the surface layer is likely to occur, and low molecular components contained in the adjacent layer migrate to the surface layer, resulting in inhibition of curing or as an electrophotographic photoconductor. This is not preferable, for example, because the electrical characteristics are degraded. Therefore, the surface temperature of the photoconductor during light irradiation is 100 ° C. or lower, preferably 80 ° C. or lower. As a cooling method, it is possible to use a cooling agent sealed inside the photoconductor, cooling with a gas or liquid inside the photoconductor, or the like. Moreover, as the wavelength of the light to be irradiated, it is sufficient if it has at least a wavelength that the sensitizing dye absorbs.As described above, when the light of 500 nm or more is irradiated, the temperature of the irradiated object is increased, In order to degrade the charge generation material having absorption in the wavelength region of 500 nm or more, it is preferable not to irradiate the irradiated object with light having a wavelength of 500 nm or more using a wavelength cut filter or the like.

  Moreover, you may heat-process after the said light irradiation for the purpose of removing unnecessary substances, such as a solvent and a photodecomposition thing contained in the coating liquid. For heating, energy such as air, gas such as nitrogen, steam, various heat media, infrared rays, electromagnetic waves or the like can be used, and heating is performed from the coated surface side or the support side. In this step, crosslinking of the surface layer is proceeding, and the migration of low molecular components as described above into the adjacent layer hardly occurs, so if heat necessary for removing unnecessary substances such as a solvent is applied. Good. The heating temperature is not particularly limited as long as it is a temperature necessary for removing unnecessary substances, but it is preferably 70 ° C. or higher and lower than 170 ° C. If it is less than 70 ° C., unnecessary substances such as a solvent are likely to be insufficiently removed.

  The film thickness of the surface layer is preferably 2 to 20 μm or less, preferably 3 to 15 μm from the viewpoint of protecting the photosensitive layer. When the surface layer is thin, not only the photosensitive layer cannot be protected from mechanical abrasion due to the contact member to the photosensitive member or proximity discharge by a charger, etc., but also the film surface becomes difficult to level during film formation. It may be crumpled. Further, when the surface layer is provided with a light shielding function as described in the present invention, the amount of light transmitted to the photosensitive layer increases when the surface layer is cured, and therefore the photosensitive layer constituting material is likely to deteriorate. On the other hand, when the surface layer is thick, the entire photoreceptor layer becomes thick, and the reproducibility of the image due to the diffusion of charges is not preferable.

<About adhesive layer>
For the purpose of preventing delamination due to poor adhesion between the surface layer / photosensitive layer, an adhesive layer may be provided between both layers as necessary.
As the adhesive layer, the radical polymerizable monomer may be used, or a non-crosslinked polymer compound may be used. Non-crosslinked polymer compounds include polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, polyacrylamide, and polyvinyl benzal. , Polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone and the like, but are not limited thereto. Further, the radical polymerizable monomer and the non-crosslinked polymer compound may be used alone or in a mixture of two or more. Furthermore, a radical polymerizable monomer and a non-crosslinked polymer compound may be used in combination as long as sufficient adhesiveness is obtained. Of course, the charge transport material described in the present specification may be used or used in combination. Moreover, an additive may be used as appropriate for the purpose of improving the adhesiveness.

  The adhesive layer is formed by applying a coating solution prepared by dissolving or dispersing a compound formulated in a prescribed formulation in a solvent such as tetrahydrofuran, dioxane, dichloroethane, or cyclohexane by dip coating, spray coating, bead coating, or ring coating. it can. The thickness of the adhesive layer is suitably about 0.1 to 5 μm, preferably 0.1 to 3 μm is most suitable.

<About photosensitive layer>
Next, the photosensitive layer will be described. As described above, the photosensitive layer may have a function separation type laminated structure or a single layer structure. In the case of a laminated structure, the photosensitive layer is generally formed from a charge generation layer and a charge transport layer. In the case of a single layer structure, the photosensitive layer is a layer having a charge generation function and a charge transport function at the same time. Hereinafter, each of the photosensitive layer having a laminated structure and the photosensitive layer having a single layer structure will be described.

<In case of laminated structure>
Since the charge generation function and the charge transport function are provided by independent layers, the photosensitive layer layer has a structure in which at least a charge generation layer and a charge transport layer are stacked on a conductive support. The order of stacking is not particularly limited, but many charge generation materials have poor chemical stability, and the charge generation efficiency decreases when exposed to acidic gases such as discharge products around the charger in the electrophotographic imaging process. Cause. For this reason, a charge transport layer is preferably laminated on the charge generation layer.

<About the charge generation layer>
The charge generation layer is a layer mainly composed of a charge generation material having a charge generation function, and a binder resin can be used in combination as necessary. 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 triarylamine 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.

  As a binder resin used as necessary for the charge generation layer, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, Examples include polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, and polyvinyl pyrrolidone. These binder resins can be used alone or as a mixture of two or more. The amount of the binder resin is suitably 0 to 500 parts by weight, preferably 10 to 300 parts by weight with respect to 100 parts by weight of the charge generating material. The binder resin may be added before or after dispersion.

Methods for forming the charge generation layer include a vacuum thin film preparation method and a casting method from a solution dispersion system. As the former method, a vacuum deposition method, a glow discharge decomposition method, an ion plating method, a sputtering method, a reactive sputtering method, a CVD method, or the like is used, and the above-described inorganic materials and organic materials can be satisfactorily formed. In addition, in order to provide the charge generation layer by the latter casting method, the inorganic or organic charge generation material described above together with a binder resin, if necessary, tetrahydrofuran, dioxane, dioxolane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, cyclohexane. It can be formed by dispersing with a ball mill, attritor, sand mill, bead mill or the like using a solvent such as pentanone, anisole, xylene, methyl ethyl ketone, acetone, ethyl acetate, butyl acetate, etc., and applying the solution after appropriately diluting the dispersion. Moreover, leveling agents, such as a dimethyl silicone oil and a methylphenyl silicone oil, can be added as needed. The application can be performed by dip coating, spray coating, bead coating, ring coating, or the like.
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.

<About the charge transport layer>
The charge transport layer is a layer having a charge transport function, and is a layer mainly composed of a charge transport material and a binder resin.
Examples of the charge transport material include a hole transport material and an electron transport material.
Examples of the charge transport material include a hole transport material and an electron transport material as described in the section of the surface layer. As the charge transport material used for the surface layer, compounds having the above-described charge transport structure and having no polymerizable functional group can be mainly used. Further, a charge transport material having a polymerizable functional group may be used in combination for improving the adhesion between the surface layer and the photosensitive layer. As the charge transporting material used for the charge transporting layer, the above-mentioned compound having no polymerizable functional group may be used alone, or a compound having no polymerizable functional group and / or a compound having it may be used in combination.

Examples of the binder resin include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, poly Vinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, Thermoplastic or thermosetting resins such as phenol resin and alkyd resin are listed. In addition, as a binder resin, a polymer charge transport material having a charge transport function, for example, a polycarbonate, polyester, polyurethane, polyether, or polyamine having an arylamine skeleton, a benzidine skeleton, a hydrazone skeleton, a carbazole skeleton, a stilbene skeleton, a pyrazoline skeleton, or the like. Polymer materials such as siloxane and acrylic resins, polymer materials having a polysilane skeleton, and the like can be used and are useful.
The amount of the charge transport material is 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. However, when a polymer charge transport material is used, it may be used alone or in combination with a binder resin.

  Examples of the solvent used here include tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, and acetone. These may be used alone or in combination of two or more.

If necessary, a plasticizer and a leveling agent can be added. As the plasticizer used for the charge transport layer, those used as plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are. About 30 parts by weight is appropriate. Examples of leveling agents that can be used in the charge transport layer include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain. About 0 to 1 part by weight is appropriate for the part by weight.
The thickness of the charge transport layer is preferably 30 μm or less, more preferably 25 μm or less, from the viewpoint of resolution and responsiveness. Regarding the lower limit, although it differs depending on the system to be used (particularly, the charging potential), 5 μm or more is preferable.

<When the photosensitive layer is a single layer>
A photosensitive layer having a single layer structure is a layer having both a charge generation function and a charge transport function. The photosensitive layer can be formed by dissolving or dispersing a charge generating substance, a charge transporting substance, and a binder resin in a suitable solvent, and applying and drying them. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.

  As the binder resin, in addition to the binder resin previously mentioned in the charge transport layer, the binder resin mentioned in the charge generation layer may be mixed and used. Of course, the polymer charge transport materials mentioned above can also be used favorably. The amount of the charge generating material with respect to 100 parts by weight of the binder resin is preferably 5 to 40 parts by weight, and the amount of the charge transporting material is preferably 0 to 190 parts by weight, and more preferably 50 to 150 parts by weight. The photosensitive layer is formed by dip coating, spray coating, bead coating, ring coating with a charge generating material, a binder resin and a charge transport material dispersed in a disperser using a solvent such as tetrahydrofuran, dioxane, dichloroethane, and cyclohexane. It can be formed by coating with a coat. The film thickness of the photosensitive layer is suitably about 5 to 25 μm.

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

These undercoat layers can be formed using an appropriate solvent and a coating method like the above-mentioned photosensitive layer. Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the undercoat layer of the present invention. In addition, in the undercoat layer of the present invention, Al ₂ O ₃ is provided by 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.

<About other additives>
In the present invention, in order to improve the environmental resistance, in particular, for the purpose of preventing a decrease in sensitivity and an increase in residual potential, a surface layer, an adhesive layer, a photosensitive layer (in the case of laminated light, at least a charge generation layer, An antioxidant can be added to each layer such as the charge transport layer), the undercoat layer, and the intermediate layer.
The following are mentioned as antioxidant which can be used for this invention.
<Phenolic compound>
2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3,5-di-t-butyl-4 -Hydroxyphenyl) propionate, 2,2'-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2'-methylene-bis- (4-ethyl-6-tert-butylphenol), 4, 4'-thiobis- (3-methyl-6-tert-butylphenol), 4,4'-butylidenebis- (3-methyl-6-tert-butylphenol), 1,1,3-tris- (2-methyl-4 -Hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [meth -3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3'-bis (4'-hydroxy-3'-t-butylphenyl) buty Rick acid] cricol ester, tocopherols and the like.

<Paraphenylenediamines>
N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N'- Di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine and the like.
<Hydroquinones>
2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2-octadecenyl) ) -5-methylhydroquinone and the like.
<Organic sulfur compounds>
Dilauryl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, ditetradecyl-3,3'-thiodipropionate and the like.
<Organic phosphorus compounds>
Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine, and the like.
These compounds are known as antioxidants such as rubbers, plastics, oils and fats, and commercially available products can be easily obtained.
The addition amount of the antioxidant in this invention is 0.01-10 weight part with respect to the total weight of the layer to add.

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

In addition, the conductive support dispersed in an appropriate binder resin on the support can be used as the conductive support of the present invention. Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc and silver, or metal oxide powder such as conductive tin oxide and ITO. Can be mentioned. The binder resin used at the same time includes polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine Examples thereof include thermoplastic resins such as resins, urethane resins, phenol resins, and alkyd resins, thermally crosslinkable resins, and photocrosslinkable resins. Such a conductive layer can be provided by dispersing and applying 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 of the present invention.

<Protective substances>
A protective substance may be applied to the surface of the electrophotographic photosensitive member for the purpose of improving the cleaning property by reducing the surface energy of the electrophotographic photosensitive member and protecting it from electrical and mechanical hazards.
As the protective substance, various materials can be used as long as they can be uniformly applied to the surface of the electrophotographic photosensitive member, but materials such as wax, silicone oil, and fatty acid salts are effective. Fatty acid salts are particularly effective because they can be uniformly coated on the surface of the photoreceptor without causing deterioration of the electrical characteristics of the electrophotographic photoreceptor. Examples of fatty acids include undecyl acid, lauric acid, tridecyl acid, myristic acid, palmitic acid, pendadecyl acid, stearic acid, heptadecyl acid, arachidic acid, montanic acid, oleic acid, arachidonic acid, caprylic acid, capric acid, caproic acid, etc. Examples of the metal salt include salts with metals such as zinc, iron, copper, magnesium, aluminum, and calcium.

  Furthermore, it is preferable to use a lamellar crystal powder such as zinc stearate as a protective substance. A lamellar crystal has a layered structure in which amphiphilic molecules are self-organized, and when a shearing force is applied, the crystal breaks along the layers and is slippery. This action is effective for lowering the coefficient of friction, but when viewed from the viewpoint of protecting the photoreceptor surface from electric discharge, the characteristics of lamellar crystals that uniformly cover the photoreceptor surface under shearing force are as follows: Since the surface of the photoreceptor can be effectively covered with a small amount of protective material, it is desirable as a protective material.

  The method for applying the protective substance is not particularly limited, and examples thereof include a method in which a protective substance is applied in advance to a member such as a cleaning member that contacts the photosensitive member, and a method in which a dedicated application member is integrated with the process cartridge. . Providing a dedicated application member is preferable because a stable amount can be applied over a long period of time.

<< Configuration of image forming apparatus >>
Next, an image forming apparatus and a process cartridge for an image forming apparatus according to the present invention will be described in detail with reference to the drawings.
The image forming apparatus of the present invention uses a photoconductor having the cross-linked surface layer. For example, at least after the photoconductor is charged, exposed to an image, and developed, the toner image on the image carrier (transfer paper) is transferred. The process includes transfer, fixing, and cleaning of the surface of the photoreceptor.
In some cases, an image forming apparatus that directly transfers an electrostatic latent image to a transfer body and develops the image forming apparatus does not necessarily have the above-described process disposed on a photoconductor.
FIG. 5 is a schematic diagram illustrating an example of an image forming apparatus. A charging charger (3) is used as a means for charging the photoconductor on average. As the charging means, a corotron device, a scorotron device, a solid discharge element, a needle electrode device, a roller charging device, a conductive brush device, or the like is used, and a known method can be used.

Next, the image exposure unit (5) is used to form an electrostatic latent image on the uniformly charged photoreceptor (1). As this light source, all luminescent materials such as fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light emitting diodes (LEDs), semiconductor lasers (LD), and electroluminescence (EL) can be used. Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.
Next, the developing unit (6) is used to visualize the electrostatic latent image formed on the photoreceptor (1). Development methods include a one-component development method using a dry toner, a two-component development method, and a wet development method using a wet toner. When the photosensitive member is positively (negatively) charged and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. If this is developed with toner of negative (positive) polarity (detection fine particles), a positive image can be obtained, and if developed with toner of positive (negative) polarity, a negative image can be obtained.

Next, the transfer charger (10) is used to transfer the toner image visualized on the photosensitive member onto the transfer member (9). In addition, a pre-transfer charger (7) may be used for better transfer. As these transfer means, a transfer charger, an electrostatic transfer method using a bias roller, a mechanical transfer method such as an adhesive transfer method and a pressure transfer method, and a magnetic transfer method can be used. As the electrostatic transfer method, the charging means can be used.
Next, a separation charger (11) and a separation claw (12) are used as means for separating the transfer body (9) from the photoreceptor (1). As other separation means, electrostatic adsorption induction separation, side end belt separation, tip grip conveyance, curvature separation, and the like are used. As the separation charger (11), the charging means can be used.

Next, a fur brush (14) and a cleaning blade (15) are used to clean the toner remaining on the photoreceptor after transfer. Further, a pre-cleaning charger (13) may be used in order to perform cleaning more efficiently. As other cleaning means, there are a web system, a magnet brush system, and the like, but a single system or a plurality of systems may be used together.
Next, a neutralizing unit is used for the purpose of removing the latent image on the photoreceptor as required. As the charge removal means, a charge removal lamp (2) and a charge removal charger are used, and the exposure light source and the charging means can be used respectively.
In addition, known processes can be used for reading, feeding, fixing, paper discharge and the like that are not close to the photoconductor.

The present invention is an image forming method and an image forming apparatus using the electrophotographic photoreceptor according to the present invention for such image forming means.
The image forming means may be fixedly incorporated in a copying apparatus, facsimile, or printer, but may be incorporated in these apparatuses in the form of a process cartridge and detachable. An example of the process cartridge is shown in FIG.
The process cartridge for the image forming apparatus includes a photoreceptor (101), and in addition, a charging unit (102), a developing unit (104), a transfer unit (106), a cleaning unit (107), and a discharging unit (not shown). ), And an apparatus (part) that can be attached to and detached from the image forming apparatus main body.

  Referring to the image forming process by the apparatus illustrated in FIG. 6, the surface of the photoconductor (101) is exposed by charging by the charging means (102) and exposure by the exposure means (103) while rotating in the direction of the arrow. An electrostatic latent image corresponding to the image is formed, and the electrostatic latent image is developed with toner by the developing means (104). The toner development is transferred to the transfer body (105) by the transfer means (106), and printed. Be out. Next, the surface of the photoconductor after the image transfer is cleaned by a cleaning unit (107), and further neutralized by a neutralizing unit (not shown), and the above operation is repeated again.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to a following example.
<Example 1>
<< Method for producing photoconductor >>
By coating and drying an undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution in the following order on a φ30 mm aluminum cylinder in sequence, an undercoat layer of 3.5 μm A 0.2 μm charge generation layer and an 18 μm charge transport layer were formed.
[Coating liquid for undercoat layer]
・ Alkyd resin 6 parts by weight (Beckosol 1307-60-EL, manufactured by Dainippon Ink & Chemicals, Inc.)
Melamine resin 4 parts by weight (Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals)
・ Titanium oxide 40 parts by weight ・ Methyl ethyl ketone 50 parts by weight

・ポリビニルブチラール（ＸＹＨＬ、ＵＣＣ製） ０．５重量部
・シクロヘキサノン ２００重量部
・メチルエチルケトン ８０重量部 [Coating liquid for charge generation layer]
-2.5 parts by weight of a bisazo pigment pigment of the following structural formula (1)

-Polyvinyl butyral (XYHL, manufactured by UCC) 0.5 parts by weight-Cyclohexanone 200 parts by weight-Methyl ethyl ketone 80 parts by weight

・テトラヒドロフラン １００重量部
・１％シリコーンオイルのテトラヒドロフラン溶液 １重量部
（ＫＦ５０−１００ＣＳ、信越化学工業製） [Coating liquid for charge transport layer]
-10 parts by weight of bisphenol Z polycarbonate (Panlite TS-2050, manufactured by Teijin Chemicals)
-7 parts by weight of low molecular charge transport material of the following structural formula (2)

Tetrahydrofuran 100 parts by weight 1% silicone oil tetrahydrofuran solution 1 part by weight (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

Subsequently, a surface layer coating solution having the following composition was applied onto the laminate comprising the conductive support / undercoat layer / charge generation layer / charge transport layer, and then a Fusion UV lamp system (Fusion Corporation: D bulb). ), The surface layer was cross-linked by light irradiation under the conditions of illuminance: 500 mW / cm ² and irradiation time: 90 seconds to obtain a 5 μm-surface cured film. At the time of curing, a heat ray cut filter having the characteristics shown in FIG. 7 was installed between the electrophotographic photosensitive member and the UV light source. The irradiated light had light with a wavelength of at least 370 to 480 nm. Thereafter, drying was performed at 130 ° C. for 30 minutes to obtain an electrophotographic photosensitive member comprising a conductive support / undercoat layer / charge generation layer / charge transport layer / surface layer.

・下記構造式（４）の電荷輸送性構造を有しないラジカル重合性化合物 ９５重量部

・増感色素 ２．６重量部
4-(Dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran
（NK-3502，林原生物化学研究所）
・光重合開始剤 １０重量部
１−ヒドロキシ−シクロヘキシル−フェニル−ケトン
（イルガキュアＩ−１８４，チバ・スペシャルティ・ケミカルズ社製）
・テトラヒドロフラン １２００重量部 [Coating liquid for surface layer]
-95 parts by weight of a compound having a charge transporting structure represented by the following structural formula (3)

-Radical polymerizable compound having no charge transporting structure represented by the following structural formula (4) 95 parts by weight

・ Sensitizing dye 2.6 parts by weight
4- (Dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran
(NK-3502, Hayashibara Institute of Biochemistry)
Photopolymerization initiator 10 parts by weight 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure I-184, Ciba Specialty Chemicals)
・ 1200 parts by weight of tetrahydrofuran

<Example 2>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the radical polymerizable monomer having no charge transporting structure used in the surface layer coating solution of Example 1 was changed to the following.
-95 parts by weight of a radically polymerizable compound having no charge transporting structure represented by the following structural formula (5)

<Example 3>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the radical polymerizable monomer having no charge transporting structure used in the surface layer coating solution of Example 1 was changed to the following.
-95 parts by weight of a radically polymerizable compound having no charge transporting structure represented by the following structural formula (6)

<Examples 4 to 6>
The compound having the charge transporting structure used in the surface layer coating liquids of Examples 1 to 3 was changed to the following radical polymerizable compound, and the sensitizing dye content was changed to 2.4 parts by weight. An electrophotographic photosensitive member was produced in the same manner as in Examples 1 to 3.
-95 parts by weight of a compound having a charge transporting structure represented by the following structural formula (7)

<Examples 7 to 9>
Electrophotographic photosensitive members were produced in the same manner as in Examples 4 to 6 except that the sensitizing dyes used in the surface layer coating solutions of Examples 4 to 6 were changed to the following.
・ Sensitizing dye 4.2 parts by weight
3,3'-Carbonylbis (7-dibuthylaminocoumarin) (NKX-1880, Hayashibara Institute of Biochemistry)

・上記構造式（５）で示される電荷輸送性構造を有しないラジカル重合性化合物
９５重量部
・増感色素 １．８重量部
3-(2-Benzothiazolyl) -7-(diethyl amino)coumarin
（NK-1858，林原生物化学研究所）
・光重合開始剤 １０重量部
１−ヒドロキシ−シクロヘキシル−フェニル−ケトン
（イルガキュアＩ−１８４，チバ・スペシャルティ・ケミカルズ社製）
・テトラヒドロフラン １２００重量部 <Example 10>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the following coating composition was used as the surface layer coating solution.
[Coating liquid for surface layer]
-95 parts by weight of a compound having a charge transporting structure represented by the following structural formula (8)

-Radical polymerizable compound having no charge transporting structure represented by the structural formula (5)
95 parts by weight ・ Sensitizing dye 1.8 parts by weight
3- (2-Benzothiazolyl) -7- (diethyl amino) coumarin
(NK-1858, Hayashibara Biochemical Research Institute)
Photopolymerization initiator 10 parts by weight 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure I-184, Ciba Specialty Chemicals)
・ 1200 parts by weight of tetrahydrofuran

<Example 11>
An electrophotographic photosensitive member was produced in the same manner as in Example 10 except that the amount of the sensitizing dye used in the surface layer coating solution of Example 10 was changed to 5.0 parts by weight.
<Example 12>
An electrophotographic photosensitive member was produced in the same manner as in Example 5 except that the amount of the sensitizing dye used in the surface layer coating solution of Example 5 was changed to 6.6 parts by weight.
<Example 13>
An electrophotographic photosensitive member was produced in the same manner as in Example 5 except that the amount of the sensitizing dye used in the surface layer coating solution of Example 5 was changed to 3.8 parts by weight.

<Example 14>
An electrophotographic photosensitive member was produced in the same manner as in Example 5 except that the amount of the sensitizing dye used in the surface layer coating solution of Example 5 was changed to 1.8 parts by weight.
<Example 15>
The electrophotography was performed in the same manner as in Example 10 except that the amount of the sensitizing dye used in the surface layer coating solution of Example 10 was changed to 3.0 parts by weight and the film thickness of the surface layer was changed to 3 μm. A photoconductor was prepared.
<Example 16>
The electrophotography was performed in the same manner as in Example 5 except that the amount of the sensitizing dye used in the surface layer coating liquid of Example 10 was changed to 1.2 parts by weight and the film thickness of the surface layer was changed to 8 μm. A photoconductor was prepared.

<Example 17>
The compound having the charge transporting structure used in the surface layer coating solution of Example 5 was changed to the following, and the same as Example 5 except that the amount of the sensitizing dye was changed to 1.8 parts by weight. Thus, an electrophotographic photosensitive member was produced.
-95 parts by weight of a compound having a charge transporting structure represented by the following structural formula (9)

<Example 18>
The sensitizing dye used in the surface layer coating solution of Example 5 was changed to the following, and the electrophotography was performed in the same manner as in Example 5 except that the amount of the sensitizing dye was changed to 1.2 parts by weight. A photoconductor was prepared.
・ Sensitizing dye
3-Carbetoxy-7- (diethyl amino) coumarin (NKX-1253, Hayashibara Institute of Biochemistry)
<Example 19>
The sensitizing dye used in the surface layer coating solution of Example 17 was changed to the following, and the electrophotography was performed in the same manner as in Example 17 except that the amount of the sensitizing dye was changed to 0.8 parts by weight. A photoconductor was prepared.
・ Sensitizing dye
3-Carbetoxy-7- (diethyl amino) coumarin (NKX-1253, Hayashibara Institute of Biochemistry)

<Comparative Example 1>
An electrophotographic photosensitive member was produced in the same manner as in Example 2 except that the surface layer coating solution of Example 2 was changed to the following composition.
[Coating liquid for surface layer]
95 parts by weight of a compound having a charge transporting structure represented by the above structural formula (3). A radical polymerizable compound having no charge transporting structure represented by the above structural formula (5).
95 parts by weight-Photopolymerization initiator 10 parts by weight 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure I-184, manufactured by Ciba Specialty Chemicals)
・ 1200 parts by weight of tetrahydrofuran

<Comparative example 2>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 1 except that the UV exposure time in the surface layer curing of Comparative Example 1 was set to 150 seconds.
<Comparative Example 3>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 1 except that the UV exposure time in the surface layer curing of Comparative Example 1 was 240 seconds.

<Comparative example 4>
The compound having the charge transporting structure of Example 18 was changed to the compound represented by the following structural formula (10), and the amount of the sensitizing dye was changed to 0.8 parts by weight. An electrophotographic photosensitive member was produced.
A compound having a charge transporting structure represented by the following structural formula (10)

<Comparative Example 5>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 4 except that the UV exposure time in the surface layer curing of Comparative Example 4 was 150 seconds.
<Comparative Example 6>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 4 except that the UV exposure time in the surface layer curing of Comparative Example 4 was 240 seconds.

<Comparative Example 7>
An electrophotographic photosensitive member was produced in the same manner as in Example 10 except that the compound having the charge transporting structure of Example 10 was changed to the compound represented by the above structural formula (10).
<Comparative Example 8>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 7, except that the UV exposure time in the surface layer curing of Comparative Example 7 was 150 seconds.
<Comparative Example 9>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 7 except that the UV exposure time in the surface layer curing of Comparative Example 7 was 240 seconds.

<Comparative Example 10>
An electrophotographic photosensitive member was produced in the same manner as in Example 5 except that the sensitizing dye of Example 5 was changed to the following and the blending amount of the sensitizing dye was changed to 2.0 parts by weight.
・ Sensitizing dye
2-[[3-[(1,3-Dihydro-1-ethyl-3,3,5-trimethyl-2H-indol-2-ylidene) methyl] -2-hydroxy-4-oxo-2-cyclobuten-1 -ylidene] methyl] -1-ethyl-3,3,5-trimethyl-3H-indolium (NK-3906, Hayashibara Institute of Biochemistry)

<Comparative Example 11>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 7 except that the UV exposure time in the surface layer curing of Comparative Example 10 was set to 150 seconds.
<Comparative Example 12>
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 7 except that the UV exposure time in the surface layer curing of Comparative Example 10 was 240 seconds.

Table 1 shows the optical properties of the compounds having the charge transporting structure and the sensitizing dyes used in the surface layer coating solutions of Examples 1 to 19 and Comparative Examples 1 to 12, and Table 2 shows the transmittance of the cured surface layer. Shown in

《Curability test》
A solubility test for an organic solvent is performed as an index of the curing progress of the crosslinked surface layer. First, using a lapping film having a surface roughness of 0.3 μm (manufactured by Sumitomo 3M), wear the crosslinked surface layer having a width of 10 cm in the axial direction of the photoconductor at an arbitrary position of the photoconductor by about 3 μm (only about 16 μm in Example 16) I let you. Next, one drop of tetrahydrofuran (hereinafter abbreviated as THF) is dropped on the non-wear part and the wear part, and the change in the surface shape after natural drying is visually observed. In the case where the curing has not progressed, a part of the surface is dissolved, and ring-shaped unevenness and cloudiness occur.
Table 3 shows the results of solubility in THF for the electrophotographic photoreceptors of Examples 1 to 19 and Comparative Examples 1 to 12.

  In the electrophotographic photoreceptors described in Examples 1 to 19 of the present invention, no dissolution in THF was observed at the surface (non-wear part) and inside the film (wear part). On the other hand, although the electrophotographic photoreceptors of Comparative Examples 1 to 2, 4 to 5, 7, and 10 to 11 were not dissolved in THF on the surface, it was confirmed that they were dissolved in the inside of the film. In particular, those with a short UV irradiation time had large dissolution marks. For these electrophotographic photoreceptors, the absorption of the sensitizing dye coincides with the absorption of the compound having a charge transporting structure or is not matched to the light source to be used, so that the generation of radicals is efficient. It is thought that this is not done. In the electrophotographic photoreceptors of Comparative Examples 3, 6, 8 to 9 and 12, almost no dissolution in THF was observed even inside, which is considered to be because curing was further advanced due to a long UV irradiation time. It is done.

Next, durability tests were performed on the electrophotographic photosensitive members of Examples 2, 5, 8, 10 to 19 and Comparative Examples 3, 6, 8 to 9, and 12, and the results are shown in Table 4.
《Durability test》
The produced photoreceptor is mounted on a process cartridge for an electrophotographic apparatus, and the initial dark portion potential is set to -750 V by a Ricoh imagio Neo 271 remodeling machine using a 655 nm semiconductor laser as an image exposure light source. Thereafter, a paper passing test is started, and film thickness measurement is performed at the initial stage, 10,000 sheets, 30,000 sheets, and 50,000 sheets, and A4 paper passing running is performed. As electrical characteristics at the end of paper passing, the dark part and exposed part potentials are measured at the same place as the initial dark part potential measurement part. The film thickness of the photosensitive member was measured using an eddy current film thickness measuring device (manufactured by Fischer Instrument).

In the electrophotographic photoreceptors of Examples 2, 5, 8, and 10 to 17 of the present invention, the potential of the exposed portion is low at the initial stage and before and after the durability test of 50,000 sheets, and the potential fluctuation before and after running the paper is small. Further, the amount of wear was relatively small, and no extreme reduction in film thickness was observed up to 50,000 sheets. Although the electrophotographic photosensitive members of Examples 18 to 19 did not have a large wear amount, the dark portion charging potential tended to decrease slightly after passing 50,000 sheets.
On the other hand, the electrophotographic photoreceptors shown in Comparative Examples 3, 6, 8 to 9 do not have a large amount of wear, but the exposure part potential is relatively high from the beginning, compared with the electrophotographic photoreceptors shown in the examples. There was a tendency for the image density to become lighter. In addition, the dark portion charging potential tended to decrease with the passage of paper, and the dark portion potential was confirmed to decrease by 70 to 80 V after running 50,000 sheets. The main cause of this is considered to be that the photosensitive layer is deteriorated by excessive UV exposure and charging delay occurs. In Comparative Example 12, since the writing laser beam (655 nm) is shielded by the added sensitizing dye, it is considered that charge generation in the photosensitive layer is not sufficiently performed, and as a result, the potential of the exposed portion is not sufficiently decreased. .

The electrophotographic photosensitive members of Examples 2, 5, 8, and 10 to 19 of the present invention showed that in a durability test of 50,000 sheets, the amount of film thickness reduction was small and good electrical characteristics were maintained.
Therefore, as described in the present invention, when a surface layer to be cured by light irradiation is laminated on the photosensitive layer surface, the surface layer is crosslinked using at least one sensitizing dye and a polymerization initiator, The absorption edge wavelength λe (nm) on the long wavelength side in the optical absorption spectrum of the compound having a charge transporting structure is less than 480 nm, and the maximum absorption wavelength λmax (nm) of the sensitizing dye is λe (nm) or more and 480 nm or less. It has been found that some electrophotographic photoreceptors are excellent in abrasion resistance, have a low exposed area potential, and have little fluctuation in surface potential even when used. Further, it has been found that the image forming process, the image forming apparatus, and the process cartridge for the image forming apparatus using the photoconductor of the present invention have high performance and high reliability.

FIG. 2 is a cross-sectional view of a photoconductor of an embodiment of the present invention, showing an example in which the photosensitive layer is a single layer. Similarly, an example in which the photosensitive layer is laminated is shown. Similarly, an example in which the photosensitive layer is laminated is shown. The measurement result of the light absorbency vs wavelength of the sensitizing dye prescribed | regulated by this invention is shown. 1 is a schematic diagram illustrating an example of an image forming apparatus. An example of a process cartridge is shown. The characteristic of the heat ray cut filter used in the Example is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Graduation lamp 3 Charger charger 5 Image exposure part 6 Developing unit 7 Charger before transfer 9 Transferr 10 Transfer charger 11 Separation charger 12 Separation claw 13 Charger before cleaning 14 Fur brush 15 Cleaning blade 31 Conductive support 32 Charge Generation layer 33 Charge transport layer 34 Single layer photosensitive layer 35 Surface layer 101 Photoconductor 102 Charging means 103 Exposure means 104 Developing means 105 Transfer body 106 Transfer means 107 Cleaning means

Claims (11)

  It has at least a photosensitive layer and a surface layer in this order on a conductive support, and the surface layer crosslinks a compound having a charge transporting structure and a radical polymerizable monomer not having a charge transporting structure by light energy irradiation means. In the electrophotographic photoreceptor formed by the above process, the surface layer is crosslinked using at least one sensitizing dye and a polymerization initiator, and has a long wavelength in the optical absorption spectrum of the compound having the charge transporting structure. An electrophotographic photoreceptor, wherein the absorption edge wavelength λe (nm) on the side is less than 480 nm, and the maximum absorption wavelength λmax (nm) of the sensitizing dye is λe (nm) or more and 500 nm or less.   2. The electrophotographic photosensitive member according to claim 1, wherein the transmittance of the surface layer is 60% or less in at least a wavelength region of λe (nm) or more and 480 nm or less.   The electrophotographic photosensitive member according to claim 1 or 2, wherein the sensitizing dye has a molar extinction coefficient at λe (nm) and 480 nm of 10,000 l / mol · cm or more.   The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the compound having a charge transporting structure used for the surface layer has a radical polymerizable functional group.   5. The electrophotographic photosensitive member according to claim 4, wherein the radical polymerizable functional group of the compound having a charge transporting structure is an acryloyloxy group or a methacryloyloxy group.   6. The electrophotographic photosensitive member according to claim 1, wherein the charge transporting structure of the compound having the charge transporting structure is a triarylamine structure.   7. The electrophotographic photosensitive member according to claim 4, wherein the compound having a charge transporting structure has one radical polymerizable functional group.   8. The electrophotographic photoreceptor according to claim 1, wherein the radical polymerizable functional group of the radical polymerizable monomer having no charge transporting structure is an acryloyloxy group or a methacryloyloxy group.   A charging process for charging at least the electrophotographic photosensitive member using the electrophotographic photosensitive member according to any one of claims 1 to 8, and forming an electrostatic latent image on the surface of the electrophotographic photosensitive member charged by the charging process. A latent image forming process, a developing process for attaching toner to the electrostatic latent image formed by the latent image forming process, and a transfer process for transferring the toner image formed by the developing process to the transfer target are repeated. An image forming method.   9. The electrophotographic photosensitive member according to claim 1, a charger for charging at least the electrophotographic photosensitive member, and a latent image for forming an electrostatic latent image on the surface of the electrophotographic photosensitive member charged by the charger. An image forming apparatus comprising: a forming unit; a developing unit that attaches toner to an electrostatic latent image formed by the latent image forming unit; and a transfer unit that transfers a toner image formed by the developing unit to a transfer target.   9. The electrophotographic photosensitive member according to claim 1, a charger for charging at least the electrophotographic photosensitive member, and a latent image for forming an electrostatic latent image on the surface of the electrophotographic photosensitive member charged by the charger. An image forming unit; a developing unit that attaches toner to the electrostatic latent image formed by the latent image forming unit; a transfer unit that transfers the toner image formed by the developing unit to a transfer target; and an electrophotographic photosensitive member after transfer An image forming apparatus comprising one means selected from the group consisting of a cleaning device for removing toner remaining on the surface of the body from the surface of the electrophotographic photosensitive member, wherein the image forming apparatus body is removable. Process cartridge for equipment.

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