JP2013007993A - Electrostatic latent image carrier, image forming device and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic latent image carrier that exhibits excellent abrasion resistance and electric characteristics, while suppressing uneven image density and image blur.SOLUTION: The electrostatic latent image carrier has a photosensitive layer 12 formed on a conductive support 11. The surface of the photosensitive layer has a crosslinked surface layer including a monofunctional radical polymerizable compound represented by the general formula (1), a trifunctional or higher radial polymerizable compound having no charge transport structure, and a radical polymerizable compound having the charge transport structure. The crosslinked surface layer contains an oxazole compound represented by the general formula (2).

Description

  The present invention relates to an electrostatic latent image carrier, an image forming apparatus, and a process cartridge.

  In the image forming apparatus, an image is formed by subjecting the electrostatic latent image carrier (photoconductor) to a charging process, an exposure process, a development process, a transfer process, and the like. At this time, discharge products generated in the charging step and untransferred residual toner that has not been transferred adhere to the electrostatic latent image carrier. Therefore, after the transfer process, the electrostatic latent image carrier is subjected to a cleaning process to remove discharge products and residual toner.

  In the cleaning process, generally, a rubber blade is pressed against the electrostatic latent image carrier to remove residues on the surface of the electrostatic latent image carrier. However, the stress due to friction between the surface of the electrostatic latent image carrier and the cleaning blade is large, resulting in wear of the rubber blade and the surface layer of the electrostatic latent image carrier, resulting in the life of the rubber blade and the organic electrostatic latent image carrier. To shorten. Therefore, it is necessary to reduce the deterioration of the electrostatic latent image carrier due to friction.

  As a technique for improving the wear resistance of the electrostatic latent image carrier, there is a method of forming a crosslinked surface layer (crosslinked resin layer) on the surface of the electrostatic latent image carrier. However, when the electrostatic latent image bearing member having the crosslinked surface layer is left for a long time after repeated use, the resistance value of the surface portion in the vicinity of the charger decreases, and when it is restarted, the charged potential and the post-exposure potential are reduced. , And density unevenness may occur. In addition, in the case of an electrostatic latent image carrier in which a charge transport layer is provided below the cross-linked resin layer, image blurring and residual potential increase may occur when used repeatedly for a long time.

  Therefore, Patent Document 1 discloses a technique in which a crosslinked surface layer is formed on the surface of an electrostatic latent image carrier, and two or more kinds of antioxidants are contained in the crosslinked resin layer.

  However, the electrostatic latent image carrier of Patent Document 1 cannot sufficiently suppress the above-described abnormal image.

  Accordingly, an object of the present invention is to provide an electrostatic latent image carrier that is excellent in wear resistance and electrical characteristics and suppresses image density unevenness and image blur.

According to the present invention,
In the electrostatic latent image carrier having a photosensitive layer on a conductive support, the surface of the photosensitive layer is
A monofunctional radically polymerizable compound represented by the following general formula (1) and having a molecular weight ratio of 300 or less to the number of radically polymerizable functional groups;
A tri- or higher functional radical polymerizable compound having no charge transporting structure;
A radically polymerizable compound having a charge transporting structure;
Having a crosslinked surface layer comprising
The crosslinked surface layer further provides an electrostatic latent image carrier containing an oxazole compound represented by the following general formula (2) or the following general formula (3).

（一般式（１）中、Ｘａはラジカル重合性官能基を表し、Ｒは水素原子、ハロゲン原子、カルボキシル基又は置換基により置換されていてもよいアルキル基を表し、Ｙ_１は置換基により置換されていてもよい二価のアルキレンオキサイド基を表し、Ｙ_２は単結合、エーテル結合又はエステル結合を表し、ｍは１又は２である。）

(In general formula (1), Xa represents a radical polymerizable functional group, R represents a hydrogen atom, a halogen atom, a carboxyl group or an alkyl group which may be substituted by a substituent, and Y ₁ is substituted by a substituent. A divalent alkylene oxide group which may be substituted, Y ₂ represents a single bond, an ether bond or an ester bond, and m is 1 or 2.)

（一般式（２）中、Ｒａ及びＲｂは、それぞれ独立に、水素原子又は炭素数１〜４のアルキル基を表し、Ｚｘは、ビニレン基、炭素数６〜１４の芳香族炭化水素の２価基又は２，５−チオフェンジイル基を表す。）

(In General Formula (2), Ra and Rb each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and Zx represents a divalent vinylene group or an aromatic hydrocarbon having 6 to 14 carbon atoms. Group or a 2,5-thiophenediyl group.)

（一般式（３）中、Ａｒ_ｘとＡｒ_ｙは、それぞれ独立に、炭素数６〜１４の芳香族炭化水素の１価基を表し、Ｚｙは、炭素数６〜１４の芳香族炭化水素の２価基を表し、Ｒｃ及びＲｄは、それぞれ独立に、水素原子又はメチル基を表す。）

(In the general formula (3), Ar _x and Ar _y each independently represent a monovalent radical of an aromatic hydrocarbon having 6 to 14 carbon atoms, Zy is aromatic hydrocarbon having 6 to 14 carbon atoms Represents a divalent group, and Rc and Rd each independently represent a hydrogen atom or a methyl group.)

  According to the present invention, it is possible to provide an electrostatic latent image carrier that has excellent wear resistance and suppresses image density unevenness and image blur.

FIG. 1 is a cross-sectional view of an example of the layer structure of the electrostatic latent image carrier of the present invention. FIG. 2 is a cross-sectional view of another example of the layer structure of the electrostatic latent image carrier of the present invention. FIG. 3 is a cross-sectional view of still another example of the layer structure of the electrostatic latent image carrier of the present invention. FIG. 4 is a cross-sectional view of still another example of the layer structure of the electrostatic latent image carrier of the present invention. FIG. 5 is a schematic view showing an example of an image forming apparatus according to the present invention. FIG. 6 is a schematic configuration diagram showing another example of the image forming apparatus according to the present invention. FIG. 7 is a schematic view showing an example of a process cartridge according to the present invention. FIG. 8 is a schematic diagram for explaining the method for measuring the elastic displacement rate of the crosslinked surface layer according to the present invention. FIG. 9 is an example of a curve showing the relationship between the indentation depth and the load obtained by the measurement method of FIG.

[Simple configuration of electrostatic latent image carrier]
The electrostatic latent image carrier according to the present invention particularly has a photosensitive layer on a conductive support, and the surface of the photosensitive layer has a crosslinked surface layer described in detail below. It is not limited. For example, you may have a protective layer, an intermediate | middle layer, and / or another layer as needed.

≪Single layer type photosensitive layer≫
FIG. 1 shows a cross-sectional view of an example of a layer structure of an electrostatic latent image carrier according to the present invention. In FIG. 1, the electrostatic latent image carrier 10 </ b> A has a single-layer type photosensitive layer 12 on a support 11. At this time, you may have a protective layer, an intermediate | middle layer, and another layer as needed.

≪Multilayer type photosensitive layer≫
FIG. 2 is a sectional view showing another example of the layer structure of the electrostatic latent image carrier according to the present invention. In FIG. 2, the electrostatic latent image carrier 10 </ b> B includes a support 11, a charge generation layer 13, and a charge transport layer 14 sequentially stacked on the support 11 to provide a stacked photosensitive layer. That is, the photosensitive layer 12 is a type in which the charge generation layer 13 and the charge transport layer 14 are functionally separated. Moreover, you may have a protective layer, an intermediate | middle layer, and another layer as needed. Further, the charge generation layer and the charge transport layer may be laminated in the reverse order.

  FIG. 3 is a sectional view showing still another example of the layer structure of the electrostatic latent image carrier according to the present invention. The electrostatic latent image carrier 10 </ b> C has the same configuration as the electrostatic latent image carrier 10 </ b> B in FIG. 2 except that an undercoat layer 15 is formed between the support 11 and the charge generation layer 13.

  FIG. 4 is a sectional view showing still another example of the layer structure of the electrostatic latent image carrier according to the present invention. The electrostatic latent image carrier 10D has the same configuration as the electrostatic latent image carrier 10C of FIG. 3 except that the protective layer 16 is formed on the charge transport layer 14.

[Crosslinked surface layer]
The cross-linked surface layer is a layer having a cross-linked structure having a charge transport function, and is provided on the surface layer of the photosensitive layer in the present invention.

  The crosslinked surface layer is represented by the following general formula (1), a monofunctional radical polymerizable compound having a radical polymerizable functional group equivalent of 300 or less, a trifunctional or higher functional radical polymerizable compound having no charge transporting structure, And a radically polymerizable compound having a charge transporting structure. The radical polymerizable functional group equivalent represents the ratio of the molecular weight to the number of functional groups, and is determined by (molecular weight / number of functional groups).

［一般式（１）中、Ｘａはラジカル重合性官能基であり、
Ｒは水素原子、ハロゲン原子、カルボキシル基又は、置換基により置換されていてもよいアルキル基であり、
Ｙ_１は、置換基により置換されていてもよい二価のアルキレンオキサイド基であり、
Ｙ_２は、単結合、エーテル結合又はエステル結合であり、
ｍは１又は２である。］
また、本発明の静電潜像担持体の架橋表面層は、下記一般式（２）又は下記一般式（３）で示すオキサゾール化合物を含有することが好ましい。

[In General Formula (1), Xa is a radical polymerizable functional group,
R is a hydrogen atom, a halogen atom, a carboxyl group, or an alkyl group optionally substituted by a substituent,
Y ₁ is a divalent alkylene oxide group which may be substituted with a substituent,
Y ₂ is a single bond, an ether bond or an ester bond,
m is 1 or 2. ]
Moreover, it is preferable that the crosslinked surface layer of the electrostatic latent image carrier of the present invention contains an oxazole compound represented by the following general formula (2) or the following general formula (3).

（一般式（２）中、Ｒａ及びＲｂは、それぞれ独立に、水素原子又は炭素数１〜４のアルキル基を表し、Ｚｘは、ビニレン基、炭素数６〜１４の芳香族炭化水素の２価基又は２，５−チオフェンジイル基を表す。）

(In General Formula (2), Ra and Rb each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and Zx represents a divalent vinylene group or an aromatic hydrocarbon having 6 to 14 carbon atoms. Group or a 2,5-thiophenediyl group.)

（一般式（３）中、Ａｒ_ｘとＡｒ_ｙは、それぞれ独立に、炭素数６〜１４の芳香族炭化水素の１価基を表し、Ｚｙは、炭素数６〜１４の芳香族炭化水素の２価基を表し、Ｒｃ及びＲｄは、それぞれ独立に、水素原子又はメチル基を表す。）
本明細書では、先ず、本発明の静電潜像担持体を上記の構成にすることの効果について述べ、その後、各々の構成要素で使用できる化合物などを説明する。

(In the general formula (3), Ar _x and Ar _y each independently represent a monovalent radical of an aromatic hydrocarbon having 6 to 14 carbon atoms, Zy is aromatic hydrocarbon having 6 to 14 carbon atoms Represents a divalent group, and Rc and Rd each independently represent a hydrogen atom or a methyl group.)
In this specification, first, the effect of having the above-described configuration of the electrostatic latent image bearing member of the present invention will be described, and then compounds that can be used in each component will be described.

  When forming high-quality images required for commercial printing, the electrostatic latent image carrier (photoreceptor) is required to have potential stability between printed sheets so that the exposure potential is constant over time. Is done. For this purpose, it is important to suppress the film thickness and homogeneity of the crosslinked surface layer in the electrostatic latent image bearing member, and also the presence or absence of charge traps in the crosslinked surface layer.

  In the present invention, a monofunctional radically polymerizable compound represented by the general formula (1) having a radically polymerizable functional group equivalent of 300 or less, a trifunctional or more functionally polymerizable compound having no charge transporting structure, The mixture with the radical polymerizable compound having a transporting structure is subjected to radical chain polymerization by irradiating active energy rays or the like to form a crosslinked surface layer. Here, the cross-linked surface layer further contains an oxazole compound described in detail below. By containing the oxazole compound in the cross-linked surface layer, charge traps formed in the cross-linked surface layer and the generation unevenness thereof can be suppressed. Thereby, the potential fluctuation derived from the charge trap of the obtained electrostatic latent image carrier can be suppressed, and high-quality image formation can be achieved with little change in image density even during continuous printing.

  In general, the crosslinked surface layer has a three-dimensional network structure, which improves the mechanical strength of the obtained electrostatic latent image carrier. On the other hand, since the three-dimensional network structure has high gas permeability, for example, image density unevenness and image blur may be caused. The gas permeability can be suppressed by containing a monofunctional radical polymerizable monomer having a radical polymerizable functional group equivalent of 300 or less shown in the general formula (1), but the monofunctional radical polymerizable monomer is contained. For this reason, since the components forming the three-dimensional network structure are reduced, the mechanical strength of the crosslinked surface layer may be lowered. The decrease in mechanical strength can be suppressed, for example, by increasing the irradiation amount of active energy rays such as ultraviolet rays and bringing it closer to complete crosslinking. Cause deterioration of electrical characteristics of This increases the irradiation amount of the active energy rays, thereby causing the generation of a photodegradation product of a radical polymerizable charge transporting compound responsible for charge transporting, and this product becomes a charge trap, repeatedly over time. This is because the potential of the exposed portion increases.

  The present inventors considered that by suppressing the above-described photodecomposition, the occurrence of charge traps in the crosslinked surface layer can be suppressed, and the exposure portion potential increase over time can be suppressed. Then, when the additive which does not inhibit the hardening polymerization reaction at the time of active energy ray irradiation was prevented, the oxazole compound of the general formula (2) or the general formula (3) may be added. Found to be effective. Although the details of the mechanism of the above-mentioned effect due to the addition of the oxazole compound are unknown, the radical polymerizable charge transporting compound excited by active energy rays and the oxazole compound are intermolecular exciton aggregates (Exciplex). It is considered that the decomposition reaction of the radically polymerizable charge transporting compound is suppressed by inactivating it.

  Further, the oxazole compound represented by the general formula (2) or the general formula (3) has an oxidation potential larger than that of the radical polymerizable charge transporting compound. Therefore, even when an oxazole compound is added, it does not cause a charge trap, so the charge transport ability is not reduced. Furthermore, the oxazole compound represented by the general formula (2) or the general formula (3) has a short absorption wavelength and little absorption in a wavelength region necessary for the formation (polymerization) of the crosslinked surface layer. Therefore, the formation of the crosslinked surface layer is not inhibited. Furthermore, the oxazole compound represented by the general formula (2) or the general formula (3) has an excitation potential level lower than the excitation potential level of the radical polymerizable charge transporting compound, and can easily form an exciton aggregate (Exciplex). Can be formed. That is, the photodecomposition of the radical polymerizable charge transporting compound during active energy ray irradiation can be suppressed without impairing the electrical characteristics and mechanical characteristics of the electrostatic latent image carrier (photoconductor).

  Next, each component in the crosslinked surface layer will be described in more detail.

≪Monofunctional radical polymerizable compound having a radical polymerizable functional group equivalent of 300 or less≫
The radical polymerizable functional group in the general formula (1) is not particularly limited as long as it has a carbon-carbon double bond and is radical polymerizable. Specific examples of the radical polymerizable functional group include a 1-substituted ethylene functional group and a 1,1-substituted ethylene functional group shown below.

As the 1-substituted ethylene functional group, the general formula CH ₂ ═CH—X ₁ —
Wherein X ₁ is an arylene group which may be substituted with a substituent, an alkenylene group which may be substituted with a substituent, a —CO— group, a —COO— group, a general formula —CON (R1) — Group (wherein R ₁ represents a hydrogen atom, an alkyl group, an aralkyl group or an aryl group)
Or a thio group. )
The group represented by these is mentioned.

Examples of the arylene group for X ₁ include a phenylene group and a naphthylene group. In addition, examples of the alkenylene group in X ₁ include a vinylene group.

Examples of the alkyl group for R ₁ include a methyl group and an ethyl group. In addition, examples of the aralkyl group in R ₁ include a benzyl group, a naphthylmethyl group, and a phenethyl group. Furthermore, examples of the aryl group in R ₁ include a phenyl group and a naphthyl group.

Specific examples of the 1-substituted ethylene functional group include vinyl group, styryl group, 2-methyl-1,3-butadienyl group, vinylcarbonyl group, acryloyloxy group, acryloylamide group, vinylthioether group and the like.
As the 1,1-substituted ethylene functional group, the following general formula CH ₂ ═C (Y) —X ₂ —
Wherein X ₂ is a group, a single bond or an alkylene group described in X ₁ above, and Y is an alkyl group which may be substituted with a substituent, or may be substituted with a substituent. An aralkyl group, an aryl group optionally substituted by a substituent, a halogen atom, a cyano group, a nitro group, an alkoxy group, a general formula —COOR ₂ group (wherein R ₂ is a hydrogen atom, substituted by a substituent) An optionally substituted alkyl group, an aralkyl group optionally substituted by a substituent, and an aryl group optionally substituted by a substituent)
Or a group represented by the general formula -CONR ₃ R ₄
(Wherein R ₃ and R ₄ are each independently a hydrogen atom, an alkyl group optionally substituted with a substituent, an aralkyl group optionally substituted with a substituent, or a substituent. Aryl group)
It is group represented by these. )
In this, Y, either one of X ₂ is an oxycarbonyl group, a cyano group, or alkenylene group, or an aromatic ring.

  Examples of the aryl group of the 1,1-substituted ethylene functional group include a phenyl group and a naphthyl group. Examples of the alkoxy group include a methoxy group and an ethoxy group, and examples of the aralkyl group include benzyl, naphthylmethyl group, and phenethyl group. Furthermore, examples of the alkyl group include a methyl group and an ethyl group.

  Specific examples of the 1,1-substituted ethylene functional group include an α-acryloyloxy group, a methacryloyloxy group, an α-cyanoethylene group, an α-cyanoacryloyloxy group, an α-cyanophenylene group, and a methacryloylamino group. It is done.

Examples of the substituent in X ₁ , X ₂ , Y, R ₂ , R ₃ and R ₄ include a halogen atom, a nitro group, a cyano group, a methyl group, an alkyl group such as an ethyl group, a methoxy group, and an ethoxy group. And aryloxy groups such as phenoxy group, aryl groups such as phenyl group and naphthyl group, and aralkyl groups such as benzyl group and phenethyl group.

  These radical polymerizable groups preferably have an acryloyloxy group or a methacryloyloxy group. A compound having one acryloyloxy group is obtained, for example, by ester reaction or transesterification using a compound having one hydroxyl group in its molecule, acrylic acid (salt), acrylic acid halide, and acrylic acid ester. be able to. A compound having one methacryloyloxy group can be obtained in the same manner.

  Specific examples of the monofunctional radical polymerizable compound represented by the general formula (1) and having a radical polymerizable functional group equivalent of 300 or less are shown in Table 1, but the present invention is not limited in this respect.

ラジカル重合性官能基当量が３００以下の単官能ラジカル重合性化合物は、少なくとも１つの置換基により置換されていてもよいベンゼン環を有している。三次元網目構造を形成する架橋表面層中において、前記ベンゼン環は、網目の空隙を塞ぐように作用すると考えられる。そのため、架橋表面層のガス透過性を小さくする。また、前記単官能ラジカル重合性化合物は、主に単結合により形成されているため、比較的柔軟な構造をとることができ、三次元網目構造の架橋骨格からペンダント状に枝分かれするような構造となる。そのため、より大きな空隙に入り込むことが可能であり、結果的にガスが透過する空隙が小さくなりやすいと考えられる。ラジカル重合性官能基当量が３００以下の場合、この効果が効率よく発揮される。ラジカル重合性官能基当量が３００を超える場合、ガス透過性を抑制する効果が発揮されないことがある。

A monofunctional radical polymerizable compound having a radical polymerizable functional group equivalent of 300 or less has a benzene ring which may be substituted with at least one substituent. In the crosslinked surface layer forming a three-dimensional network structure, the benzene ring is considered to act so as to close the voids of the network. Therefore, the gas permeability of the crosslinked surface layer is reduced. In addition, since the monofunctional radically polymerizable compound is mainly formed by a single bond, it can take a relatively flexible structure, and has a structure that branches from a crosslinked skeleton of a three-dimensional network structure in a pendant shape. Become. For this reason, it is possible to enter a larger gap, and as a result, the gap through which the gas permeates is likely to be reduced. This effect is efficiently exhibited when the radical polymerizable functional group equivalent is 300 or less. When the radical polymerizable functional group equivalent exceeds 300, the effect of suppressing gas permeability may not be exhibited.

  The content of the monofunctional radical polymerizable compound having a radical polymerizable functional group equivalent of 300 or less in the crosslinked surface layer is preferably 1% by mass to 50% by mass, and preferably 10% by mass to 40% by mass. More preferred.

≪Oxazole compound≫
As described above, the oxazole compound that can be used in the present invention is represented by the following general formula (2) or the following general formula (3).

（一般式（２）中、Ｒａ及びＲｂは、それぞれ独立に、水素原子又は炭素数１〜４のアルキル基を表し、Ｚｘは、ビニレン基、炭素数６〜１４の芳香族炭化水素の２価基又は２，５−チオフェンジイル基を表す。）

(In General Formula (2), Ra and Rb each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and Zx represents a divalent vinylene group or an aromatic hydrocarbon having 6 to 14 carbon atoms. Group or a 2,5-thiophenediyl group.)

（一般式（３）中、Ａｒ_ｘとＡｒ_ｙは、それぞれ独立に、炭素数６〜１４の芳香族炭化水素の１価基を表し、Ｚｙは、炭素数６〜１４の芳香族炭化水素の２価基を表し、Ｒｃ及びＲｄは、それぞれ独立に、水素原子又はメチル基を表す。）
ここで、Ｒａ及びＲｂにおける、炭素数１〜４のアルキル基としては、メチル基、エチル基、ｎ−プロピル基、ｉｓｏ−プロピル基、ｎ−ブチル基、ｉｓｏ−ブチル基、ｓｅｃ−ブチル基、ｔｅｒｔ−ブチル基などが挙げられる。また、Ｚｘにおける、炭素数６〜１４の芳香族炭化水素の２価基としては、ｏ−フェニレン基、ｐ−フェニレン基、１，４−ナフタレンジイル基、２，６−ナフタレンジイル基、９，１０−アントラセンジイル基、１，４−アントラセンジイル基、４，４'−ビフェニルジイル基、４，４'−スチルベンジイル基などが挙げられる。

(In the general formula (3), Ar _x and Ar _y each independently represent a monovalent radical of an aromatic hydrocarbon having 6 to 14 carbon atoms, Zy is aromatic hydrocarbon having 6 to 14 carbon atoms Represents a divalent group, and Rc and Rd each independently represent a hydrogen atom or a methyl group.)
Here, as the alkyl group having 1 to 4 carbon atoms in Ra and Rb, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, Examples thereof include a tert-butyl group. In addition, as a divalent group of an aromatic hydrocarbon having 6 to 14 carbon atoms in Zx, o-phenylene group, p-phenylene group, 1,4-naphthalenediyl group, 2,6-naphthalenediyl group, 9, Examples include 10-anthracenediyl group, 1,4-anthracenediyl group, 4,4′-biphenyldiyl group, 4,4′-stilbenediyl group, and the like.

Examples of the monovalent group of the aromatic hydrocarbon having 6 to 14 carbon atoms in Ar _x and A _y include aromatic groups such as a phenyl group, a 4-methylphenyl group, a 4-tert-butylphenyl group, a naphthyl group, and a biphenylyl group. A hydrocarbon group etc. are mentioned. In addition, as the divalent group of the aromatic hydrocarbon having 6 to 14 carbon atoms in Zy, o-phenylene group, p-phenylene group, 1,4-naphthalenediyl group, 2,6-naphthalenediyl group, 9, Examples include 10-anthracenediyl group, 1,4-anthracenediyl group, 4,4′-biphenyldiyl group, 4,4′-stilbenediyl group, and the like.

  Although the specific example of an oxazole compound represented by General formula (2) or General formula (3) is shown in Table 2, this invention is not limited to these.

オキサゾール化合物の含有量は、後述する電荷輸送性構造を有するラジカル重合性化合物の質量に対して、０．１〜３０質量％であることが好ましく、０．５質量％〜１０質量％であることがより好ましい。オキサゾール化合物の含有量が０．１質量％未満の場合、繰り返し経時での露光部電位変動量を低減する効果が低くなることがある。一方、オキサゾール化合物の含有量が３０質量％を超える場合、得られる静電潜像担持体の感度特性が悪化する場合がある。

The content of the oxazole compound is preferably 0.1 to 30% by mass, and preferably 0.5 to 10% by mass with respect to the mass of the radical polymerizable compound having a charge transporting structure described later. Is more preferable. When the content of the oxazole compound is less than 0.1% by mass, the effect of reducing the amount of variation in the exposed portion potential over time may be reduced. On the other hand, when the content of the oxazole compound exceeds 30% by mass, the sensitivity characteristics of the obtained electrostatic latent image carrier may be deteriorated.

  As described above, since the oxazole compound does not exhibit charge transportability, when it is excessively added to the cross-linked surface layer, the charge transportability compound is relatively reduced. Therefore, the charge transport property of the obtained electrostatic latent image carrier is lowered, which may cause sensitivity deterioration and the like. Moreover, the excessive addition of an oxazole compound may reduce the crosslinking density by a radically polymerizable compound. The reduction in the crosslinking density weakens the mechanical strength of the crosslinked surface layer and deteriorates the wear resistance of the electrostatic latent image carrier. Therefore, it is desirable to add as little as possible within the effective range. Therefore, the oxazole compound is added in an amount of 0.5% by mass to 10% by mass with respect to the mass of the radical polymerizable compound having a charge transporting structure, and the effect of suppressing the generation of charge traps and wear resistance It is preferable because both properties can be achieved.

≪Trifunctional or more radical polymerizable compound that does not have charge transportability≫
A trifunctional or higher functional radical polymerizable compound having no charge transporting property is a hole transporting structure such as triarylamine, hydrazone, pyrazoline, carbazole, or an electron such as condensed polycyclic quinone, diphenoquinone, cyano group, nitro group, etc. It means a compound that does not have an electron transporting structure such as an aromatic ring substituted by an attractive group and has three or more radically polymerizable groups. The radical polymerizable group means a group having a carbon-carbon double bond and capable of radical polymerization, and is preferably an acryloyloxy group or a methacryloyloxy group. A compound having three or more acryloyloxy groups can be obtained, for example, by subjecting a compound having three or more hydroxyl groups in the molecule, an acrylate, an acrylate halide, or an acrylate ester to an ester reaction or a transesterification reaction. . A compound having three or more methacryloyloxy groups can be obtained by the same method. In addition, the 3 or more radically polymerizable group which the trifunctional or more radically polymerizable compound which does not have charge transportability may have may be the same, or may differ.

  It is preferable that the trifunctional or higher radical polymerizable compound having no charge transporting property has a monomer having a radical polymerizable functional group equivalent of 300 or higher because the electric characteristics of the electrostatic latent image carrier are improved. The radically polymerizable compound having a charge transporting structure, which will be described later, has a large number of π electrons excellent in charge transport in the molecule. As a result, relatively high molecular weight compounds are used. When the functional group equivalent of the trifunctional or higher functional radical polymerizable compound is small, the number of crosslinking points is large and the network of the three-dimensional network structure is small. Therefore, the radically polymerizable compound having a charge transporting structure present in the crosslinked film has a small steric degree of freedom and may cause conformational distortion. As a result, the spread of π electrons is inhibited, which may cause a decrease in charge transport ability. That is, a radically polymerizable compound having three or more functional groups is preferable because it contains a monomer having a radically polymerizable functional group equivalent of 300 or more, resulting in good electrical characteristics.

  Specific examples of the trifunctional or higher functional radical polymerizable compound having no charge transporting property include trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, ethyleneoxy-modified (EO-modified) trimethylolpropane triacrylate, propylene Oxy-modified (PO-modified) trimethylolpropane triacrylate, caprolactone-modified trimethylolpropane triacrylate, HPA-modified trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol triacrylate, ECH-modified glycerol triacrylate , EO-modified glycerol triacrylate, PO-modified glycerol triacrylate, tris (a Liloxyethyl) isocyanurate, dipentaerythritol hexaacrylate (DPHA), caprolactone-modified dipentaerythritol hexaacrylate, dipentaerythritol hydroxypentaacrylate, alkyl-modified dipentaerythritol pentaacrylate, alkyl-modified dipentaerythritol tetraacrylate, alkyl-modified dipentaerythritol Examples include triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, EO-modified phosphoric acid triacrylate, 2,2,5,5-tetrahydroxymethylcyclopentanone tetraacrylate, and the like. These may be used alone or in combination of two or more, but a trifunctional or higher functional radical having a functional group equivalent of 300 or higher and having no charge transporting structure shown below. It preferably contains a polymerizable compound.

  Specific examples of the trifunctional or higher functional radical polymerizable compound having a functional group equivalent of 300 or higher and having no charge transporting structure are shown in Table 3, but the present invention is not limited thereto.

また、電荷輸送性を有さない３官能以上のラジカル重合性化合物は、官能基当量が２５０以下の化合物を含むことが好ましい。即ち、官能基当量３００以上及び官能基当量が２５０以下の、電荷輸送性を有さない３官能以上のラジカル重合性化合物を使用することがより好ましい。官能基当量が２５０以下のモノマーを含まない場合、静電潜像担持体の耐摩耗性が低下することがある。

The trifunctional or higher functional radical polymerizable compound having no charge transporting property preferably includes a compound having a functional group equivalent of 250 or less. That is, it is more preferable to use a trifunctional or higher functional radical polymerizable compound having a functional group equivalent of 300 or more and a functional group equivalent of 250 or less and having no charge transporting property. When a monomer having a functional group equivalent of 250 or less is not included, the abrasion resistance of the electrostatic latent image carrier may be lowered.

  The content of the trifunctional or higher functional radical polymerizable compound having no charge transport property in the crosslinked surface layer is usually 20 to 80% by mass, and preferably 35 to 65% by mass. When the content of the trifunctional or higher functional radical polymerizable compound having no charge transporting property is less than 20 mass%, the three-dimensional cross-linking density of the cross-linked surface layer is small, and sufficient improvement in wear resistance may not be achieved. On the other hand, when the monomer component exceeds 80% by mass, the content of the charge transporting compound is lowered, and the electrical characteristics may be deteriorated.

≪Radically polymerizable compound with charge transport structure≫
The radical polymerizable compound having a charge transporting structure is, for example, a hole transporting structure such as triarylamine, hydrazone, pyrazoline or carbazole, or electron withdrawing such as condensed polycyclic quinone, diphenoquinone, cyano group or nitro group. It means a compound having an electron transport structure such as a functional aromatic ring and having a radical polymerizable functional group. Examples of the radical polymerizable functional group are the same as those described above for the radical polymerizable compound, and among them, an acryloyloxy group and a methacryloyloxy group are preferable.

  The radically polymerizable compound having a charge transporting structure is preferably a monofunctional radically polymerizable compound having a charge transporting structure. Further, those having a triarylamine structure are preferable from the viewpoint of electrostatic characteristics. Among them, the following general formula (4)

（一般式（４）中、Ｒ_５は水素原子、ハロゲン原子、置換基により置換されていてもよいアルキル基、置換基により置換されていてもよいアラルキル基、置換基により置換されていてもよいアリール基、シアノ基、ニトロ基、アルコキシ基、一般式
−ＣＯＯＲ_６
（式中、Ｒ_６は水素原子、置換基により置換されていてもよいアルキル基、置換基により置換されていてもよいアラルキル基又は置換基により置換されていてもよいアリール基）
で表される基、ハロゲン化カルボニル基又は一般式
−ＣＯＮＲ_７Ｒ_８
（式中、Ｒ_７及びＲ_８は、それぞれ独立に、水素原子、ハロゲン原子、置換基により置換されていてもよいアルキル基、置換基により置換されていてもよいアラルキル基又は置換基により置換されていてもよいアリール基）で表される基であり、
Ａｒ_１は、それぞれ独立に、置換基により置換されていてもよい二価の芳香族基、Ａｒ_２、Ａｒ_３は、それぞれ独立に、置換基により置換されていてもよい一価の芳香族基、Ｘ_３は単結合又は一般式
−Ｙ_３−Ａｒ_４−
（式中、Ｙ_３は、単結合、置換基により置換されていてもよいアルキレン基、置換基により置換されていてもよいシクロアルキレン基、置換基により置換されていてもよいアルキレンオキシ基、オキシ基、チオ基又はビニレン基であり、Ａｒ_４は、置換基により置換されていてもよい二価の芳香族基である。）基であり、
Ｚは、置換基により置換されていてもよいアルキレン基、置換基により置換されていてもよいアルキレンオキシ基、アルキレンオキシカルボニル基であり、ｎは、０〜３の整数である。）
で表される化合物であることが、好ましい。

(In the general formula (4), R ₅ may be a hydrogen atom, a halogen atom, an alkyl group which may be substituted with a substituent, an aralkyl group which may be substituted with a substituent, or a substituent. Aryl group, cyano group, nitro group, alkoxy group, general formula -COOR ₆
(Wherein R ₆ is a hydrogen atom, an alkyl group which may be substituted with a substituent, an aralkyl group which may be substituted with a substituent, or an aryl group which may be substituted with a substituent)
A group represented by formula (I), a carbonyl halide group, or a general formula —CONR ₇ R ₈
(Wherein R ₇ and R ₈ are each independently substituted with a hydrogen atom, a halogen atom, an alkyl group optionally substituted with a substituent, an aralkyl group optionally substituted with a substituent, or a substituent. Aryl group that may be present),
Ar ₁ is each independently a divalent aromatic group that may be substituted with a substituent, and Ar ₂ and Ar ₃ are each independently a monovalent aromatic group that may be substituted with a substituent. , X ₃ is a single bond or a general formula —Y ₃ —Ar ₄ —
(Wherein Y ₃ represents a single bond, an alkylene group which may be substituted with a substituent, a cycloalkylene group which may be substituted with a substituent, an alkyleneoxy group which may be substituted with a substituent, oxy A group, a thio group or a vinylene group, and Ar ₄ is a divalent aromatic group which may be substituted with a substituent.
Z is an alkylene group which may be substituted with a substituent, an alkyleneoxy group which may be substituted with a substituent, or an alkyleneoxycarbonyl group, and n is an integer of 0 to 3. )
It is preferable that it is a compound represented by these.

Examples of the alkyl group for R ₅ include a methyl group, an ethyl group, a propyl group, and a butyl group. Further, examples of the aralkyl group in R ₅ include a benzyl group, a phenethyl group, and a naphthylmethyl group. Furthermore, examples of the aryl group for R ₅ include a phenyl group and a naphthyl group. Furthermore, examples of the alkoxy group for R ₅ include a methoxy group, an ethoxy group, and a propoxy group.

Examples of the substituent in R ₅ include halogen groups, nitro groups, cyano groups, alkyl groups such as methyl groups and ethyl groups, alkoxy groups such as methoxy groups and ethoxy groups, aryloxy groups such as phenoxy groups, phenyl groups and naphthyl groups. And aryl groups such as benzyl group and phenethyl group.

R ₅ is preferably a hydrogen atom or a methyl group.

Examples of the monovalent aromatic group in Ar ₂ and Ar ₃ include a monovalent condensed polycyclic hydrocarbon group, a monovalent non-condensed cyclic hydrocarbon group, and a monovalent heterocyclic group.

  The monovalent condensed polycyclic hydrocarbon group includes a pentanyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptaenyl group, a biphenylenyl group, an as-indacenyl group, an s-indacenyl group, a fluorenyl group, an acenaphthylenyl group, and a preadenyl group. Acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrenyl group, aceantrirenyl group, triphenylyl group, pyrenyl group, chrysenyl group, naphthacenyl group and the like. The monovalent condensed polycyclic hydrocarbon group preferably has 18 or less carbon atoms constituting the ring.

  Monovalent non-condensed cyclic hydrocarbon groups include groups derived from monocyclic hydrocarbon compounds such as benzene, diphenyl ether, polyethylene diphenyl ether, diphenyl thioether, diphenyl sulfone, biphenyl, polyphenyl, diphenylalkane, diphenylalkene, diphenylalkyne. , Groups derived from non-condensed polycyclic hydrocarbon compounds such as triphenylmethane, distyrylbenzene, 1,1-diphenylcycloalkane, polyphenylalkane and polyphenylalkene, and ring-assembled hydrocarbons such as 9,9-diphenylfluorene Examples include groups derived from compounds.

  Examples of the heterocyclic group include groups derived from heterocyclic aromatic compounds such as carbazole, dibenzofuran, dibenzothiophene, oxadiazole, and thiadiazole.

As the substituents for Ar ₃ and Ar ₄ , those listed below can be used.

[1] Halogen atom, cyano group, nitro group [2] Alkyl group At this time, the carbon number is 1 to 12, preferably 1 to 8, and preferably 1 to 4 linear or branched. . In addition, it has a phenyl group substituted with a fluorine atom, a hydroxyl group, a cyano group, an alkoxy group having 1 to 4 carbon atoms, a phenyl group or a halogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. You may do it.

  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-ethoxy Examples include ethyl group, 2-cyanoethyl group, 2-methoxyethyl group, benzyl group, 4-chlorobenzyl group, 4-methylbenzyl group, 4-phenylbenzyl group and the like.

[3] Alkoxy group The alkyl group in the alkoxy group is the same as the alkyl group in [2].

  Specifically, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, t-butoxy group, n-butoxy group, s-butoxy group, i-butoxy group, 2-hydroxyethoxy group, benzyloxy group And a trifluoromethoxy group.

[4] Aryloxy group Examples of the aryl group of the aryloxy group include a phenyl group and a naphthyl group. Moreover, you may contain a C1-C4 alkoxy group, a C1-C4 alkyl group, or a halogen atom as a substituent.

  Specific examples include a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a 4-methoxyphenoxy group, and a 4-methylphenoxy group.

[5] Alkyl mercapto group or aryl mercapto group Examples of the alkyl mercapto group include a methylthio group and an ethylthio group. Examples of the aryl mercapto group include a phenylthio group and a p-methylphenylthio group.

[6] Amino group optionally substituted by a substituent The amino group optionally substituted by a substituent has the general formula —NR ₉ R _10.
Wherein R ₉ and R ₁₀ are each independently a hydrogen atom, an alkyl group represented by [2], or an aryl group. R ₉ and R ₁₀ are bonded to form a ring structure May be formed.)
Examples of the aryl group include a phenyl group, a biphenyl group, and a naphthyl group. These may contain a C1-C4 alkoxy group, a C1-C4 alkyl group, or a halogen atom as a substituent.

  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] Alkylenedioxy group or alkylenedithio group Examples of the alkylenedioxy group include a methylenedioxy group. Examples of the alkylenedithio group include a methylenedithio group.

[8] Others Examples include a styryl group that may be substituted with a substituent, a β-phenylstyryl group that may be substituted with a substituent, a diphenylaminophenyl group, a ditolylaminophenyl group, and the like.

Examples of the divalent aromatic group in Ar ₁ and Ar ₄ include a group derived from a monovalent aromatic group in Ar ₂ and Ar ₃ .

Y ₃ number of carbon atoms of the alkylene group for is usually 1 to 12, 1 to 8 are preferred, from 1 to 4 is more preferred. The alkylene group is a fluoro group, a hydroxyl group, a cyano group, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, a halogen group, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. It may be substituted with a substituted phenyl group.

  Examples of the alkylene group include methylene group, ethylene group, n-butylene group, isopropylene group, t-butylene group, s-butylene group, n-propylene group, trifluoromethylene group, 2-hydroxyethylene group, and 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 number of carbon atoms of the cycloalkylene group in Y ₃ is usually 5-7. The cycloalkylene group may be substituted with a fluoro group, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms.

  Examples of the cycloalkylene group include a cyclohexylidene group, a cyclohexylene group, and a 3,3-dimethylcyclohexylidene group.

As the alkyleneoxy group for Y ₃ , a chemical formula —CH ₂ CH ₂ O— group, —CH ₂ CH ₂ CH ₂ O— group, — (OCH ₂ CH ₂ ) _h —O— group, or — (OCH ₂ CH ₂₎ CH ₂ ) _i —O— group, and the like. However, h and i in a formula represent the integer of 1-4, respectively.

  The alkyleneoxy group may be substituted with a substituent such as a hydroxyl group, a methyl group, or an ethyl group.

As the vinylene group in Y ₃ , — (C (R ₁₁ ) ═CH) _d — in the following general formula
[In the formula, R ₁₁ is a hydrogen atom, an alkyl group (the same as the alkyl group defined in the above [2]), a divalent aromatic group (the same as the divalent aromatic group in Ar ₂ and Ar ₃ described above). D represents 1 or 2. ]
Or a group represented by the formula: —C (R ₁₂ ) ═CH— (CH═CH) _e —
(In the formula, R ₁₂ is a hydrogen atom, an alkyl group (same as the alkyl group in [2] above), a divalent aromatic group (same as the divalent aromatic group in Ar ₂ and Ar ₃ above)). And e represents an integer of 1 to 3.)
The group etc. which are represented by these are mentioned.

  The alkylene group for Z is the same as the alkylene group for Y. Moreover, the alkyleneoxy group in Z is the same as the alkyleneoxy group in Y. Furthermore, examples of the alkyleneoxycarbonyl group for Z include a caprolactone-modified group.

  The monofunctional radically polymerizable compound having a charge transporting structure has the following general formula (5):

（一般式（５）中、Ｒ_１３は、水素原子又はメチル基であり、Ｒ_１４及びＲ_１５は、それぞれ独立に、置換基により置換されていてもよい炭素数１〜６のアルキル基であり、Ｚ１は、単結合、メチレン基、エチレン基、−ＣＨ_２ＣＨ_２Ｏ−で表される基、−ＣＨ（ＣＨ_３）ＣＨ_２Ｏ−で表される基、一般式（６）

(In General Formula (5), R ₁₃ is a hydrogen atom or a methyl group, and R ₁₄ and R ₁₅ are each independently an alkyl group having 1 to 6 carbon atoms that may be substituted with a substituent. , Z1 is a single bond, a methylene group, an ethylene group, a group represented by —CH ₂ CH ₂ O—, a group represented by —CH (CH ₃ ) CH ₂ O—, or a general formula (6)

で表される基であり、一般式（５）中ｏ、ｐ及びｑは、それぞれ独立に、０又は１であり、ｓ及びｔは、それぞれ独立に、０〜３の整数である。）
で表される化合物であることが好ましい。

In general formula (5), o, p, and q are each independently 0 or 1, and s and t are each independently an integer of 0 to 3. )
It is preferable that it is a compound represented by these.

In the general formula (5), R ₁₄ and R ₁₅ are preferably each independently a methyl group or an ethyl group.

  The content of the monofunctional radically polymerizable compound having a charge transporting structure with respect to the total amount of the crosslinked surface layer is usually 20 to 80% by mass, and preferably 35 to 65% by mass. When the content of the monofunctional radically polymerizable compound having a charge transporting structure in the cross-linked surface layer is less than 20% by mass, the charge transport performance of the cross-linked surface layer cannot be sufficiently maintained, and the sensitivity is reduced by repeated use. Deterioration of electrical characteristics such as increase in residual potential may appear. On the other hand, if it exceeds 80% by mass, the content of the trifunctional or higher-functional radical polymerizable compound having no charge transporting structure is lowered and the crosslink density is lowered, so that high wear resistance is not exhibited. There is.

  The crosslinked surface layer may further contain a bifunctional radically polymerizable compound and / or a radically polymerizable oligomer that does not have a charge transporting structure.

Examples of the bifunctional radically polymerizable compound having no charge transporting structure include 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, and 1,6-hexane. Examples include diol diacrylate, 1,6-hexanediol dimethacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, EO-modified bisphenol A diacrylate, EO-modified bisphenol F diacrylate, and neopentyl glycol diacrylate.
Examples of the radical polymerizable oligomer include epoxy acrylate oligomer, urethane acrylate oligomer, polyester acrylate oligomer and the like.

  The addition amount of the monofunctional radically polymerizable compound having no charge transporting structure, the bifunctional radically polymerizable compound having no charge transporting structure and the radically polymerizable oligomer is usually from the point of wear resistance. It is 50 mass% or less with respect to the trifunctional or more radically polymerizable compound which does not have a charge transport structure, and 30 mass% or less is preferable.

  In the present invention, the crosslinked surface layer is preferably obtained by curing at least a trifunctional or higher functional radical polymerizable compound having no charge transport structure and a radical polymerizable compound having a charge transport structure. In order to efficiently advance this curing reaction (crosslinking reaction), a crosslinked surface layer may be formed using a polymerization initiator as necessary.

  Examples of the thermal polymerization initiator include 2,5-dimethylhexane-2,5-dihydroperoxide, dicumyl peroxide, benzoyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di ( Peroxybenzoyl) hexyne-3, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, peroxide initiators such as lauroyl peroxide, azobisisobutylnitrile, azobiscyclohexanecarbonitrile Azo initiators such as methyl azobisisobutyrate, azobisisobutylamidine hydrochloride, and 4,4′-azobis-4-cyanovaleric acid. These may be used alone or in combination of two or more.

  Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2- Acetophenone-based or ketal-based photopolymerization initiators such as methyl-2-morpholino (4-methylthiophenyl) propan-1-one and 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, benzoin , Benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether, Benzoin ether photopolymerization initiators such as benzoin isopropyl ether, benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoylphenyl ether, acrylated benzophenone, 1 Benzophenone photopolymerization initiators such as 1,4-benzoylbenzene, thioxanthone photopolymerization such as 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone An initiator etc. are mentioned. These may be used alone or in combination of two or more. As photopolymerization initiators other than those described above, 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 compound, triazine compound, imidazole compound, and the like. It is done.

  When crosslinking the crosslinked surface layer, a compound having a photopolymerization promoting effect may be used alone or in combination with a photopolymerization initiator. Examples of the compound having an effect of promoting photopolymerization include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, 4,4′-dimethylamino. Examples include benzophenone.

  The addition amount of a polymerization initiator is 0.5-50 mass% normally with respect to the compound total amount which has a radical polymerization functional group, and it is preferable that it is 1-20 mass%.

[Method for forming crosslinked surface layer]
As a method for forming the crosslinked surface layer, first, the above-described compound is dissolved or dispersed in a solvent described in detail below to prepare a coating solution, which is coated and dried on the charge transport layer. Thereafter, a crosslinked surface layer is formed by initiating a curing (crosslinking) reaction by external energy such as heat or light irradiation.

  The coating liquid may further contain a plasticizer, a leveling agent, a charge transport material, and the like. Examples of the plasticizer include dibutyl phthalate and dioctyl phthalate. The addition amount of the plasticizer is usually 20% by mass or less and preferably 10% by mass or less with respect to the solid content of the coating solution.

  Examples of the leveling agent include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain. The addition amount of the leveling agent is usually 3% by mass or less with respect to the solid content of the coating solution.

  Solvents include alcohol solvents such as methanol, ethanol, propanol and butanol, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, ethers such as tetrahydrofuran, dioxane and propyl ether. System solvents, halogen solvents such as dichloromethane, dichloroethane, trichloroethane, and chlorobenzene, aromatic solvents such as benzene, toluene, and xylene, cellosolve solvents such as methyl cellosolve, ethyl cellosolve, and cellosolve acetate can be used. The above-mentioned solvent may be used individually by 1 type, and may be used in combination of 2 or more types.

  Examples of the method for applying the coating liquid include dip coating, spray coating, bead coating, or ring coating.

  When cross-linking the cross-linked surface layer, it is preferable to irradiate using an active energy ray such as an ultraviolet ray or an electron beam. Although it is possible to form a crosslinked surface layer by thermal irradiation with a thermal polymerization initiator or the like, it is possible to form a crosslinked surface layer having a high crosslinking density and a high elastic work rate by crosslinking using active energy rays. Therefore, the wear resistance can be improved, which is preferable.

  In addition, when cross-linking the cross-linked surface layer by irradiation with active energy rays, it should be performed under conditions such as nitrogen gas or rare gas (conditions with low oxygen concentration) or under cooling conditions to prevent temperature rise during irradiation. Preferably it is done.

  As the light source, a light source that emits ultraviolet light such as a high-pressure mercury lamp or a metal halide lamp can be used, but a light source that emits visible light may be used. Moreover, it is preferable that the temperature of the surface of the coating film containing a radically polymerizable compound at the time of irradiating light is 40-170 degreeC. It is preferable to control the surface temperature of the coating film using a heat medium.

Irradiation light amount is preferably 50 mW / cm ² or more 1000 mW / cm ² or less. When the irradiation light quantity is less than 50 mW / cm ² , the time required for the crosslinking reaction may be long. Further, when the amount of irradiation light exceeds 1000 mW / cm ² , heat storage during irradiation becomes intense, and the temperature rise cannot be controlled even under cooling, which may cause deformation and deterioration of electrical characteristics.

  The cured surface cross-linked layer is preferably insoluble in an organic solvent. When the curing is insufficient, the surface cross-linked layer film is usually soluble in an organic solvent. Moreover, since the crosslink density is low, the mechanical durability is low.

  Hereinafter, although the example of a specific compound is given and the formation method of a crosslinked surface layer is demonstrated, this invention is not limited to this. Trifunctional having no charge transporting structure using a compound having one acryloyloxy group as a monofunctional radical polymerizable compound having a radical polymerizable functional group equivalent of 300 or less represented by the above general formula (2) A case where a compound having three acryloyloxy groups is used as the radical polymerizable compound and a triarylamine compound having one acryloyloxy group is used as the monofunctional radical polymerizable compound having a charge transporting structure is described. To do.

  The mass ratio of the compound having one acryloyloxy group represented by the general formula (2) and the compound having three acryloyloxy groups is usually in the range of 1/9 to 7/3, preferably 4 / 6 to 6/4. The ratio of the total mass of the triarylamine compound having one acryloyloxy group, the compound having one acryloyloxy group, and the compound having three acryloyloxy groups is in the range of 3/7 to 7/3. It is preferable from the viewpoint of wear resistance and electrical properties. Moreover, 3 to 20% of a polymerization initiator and a solvent are usually added to the total mass of the compound having an acryloyloxy group to prepare a coating solution.

  For example, when a triarylamine-based donor is used as a charge transport layer, polycarbonate is used as a binder resin, and the crosslinked surface layer is formed by spray coating, a tetrahydrofuran solution is used as a solvent for the coating solution. 2-butanone, ethyl acetate and the like can be preferably used. The use ratio of the solvent in the coating solution is preferably 3 to 10 times the total amount of the acrylate compound.

  On the support such as an aluminum cylinder, for example, the undercoat layer, the charge generation layer, and the photoconductor on which the charge transport layer is sequentially laminated, the above-prepared coating solution is applied, and after touch drying, light irradiation, etc. To advance the curing reaction.

  When performing ultraviolet irradiation as a curing method, a metal halide lamp or the like can be used. The illuminance of ultraviolet irradiation is preferably 50 mW / cm 2 or more and 1000 mW / cm 2 or less. For example, when irradiating UV light of 700 mW / cm 2, the drum is rotated to uniformly irradiate all surfaces for about 2 minutes. At this time, using a heat medium or the like, control is performed so that the surface temperature does not become too high.

  After the curing is completed, in order to reduce the residual solvent, the latent electrostatic image bearing member can be obtained by heating at 100 to 150 ° C. for 10 to 30 minutes.

  In the electrostatic latent image carrier of the present invention, the thickness of the crosslinked surface layer is preferably 1 to 30 μm, more preferably 2 to 20 μm, and further preferably 4 to 15 μm. When the thickness of the cross-linked surface layer is less than 1 μm, the cross-linked surface layer film thickness is small with respect to the amount of intrusion into the surface of the electrostatic latent image carrier when the carrier adheres. Therefore, the electrostatic latent image carrier may not have sufficient durability. On the other hand, when the thickness of the crosslinked surface layer is thicker than 30 μm, the residual potential may increase. A thickness of the cross-linked surface layer of 1 to 30 μm is preferable because it has durability against abrasion and scratches, and the occurrence of residual potential is reduced.

  It is preferable to perform heating or light irradiation for the curing reaction to reduce the oxygen concentration in the ambient atmosphere because crosslinking can be promoted. Since the inhibition of radical polymerization by oxygen can be reduced by lowering the oxygen concentration in the surrounding atmosphere, a crosslinked surface layer having a high crosslinking density can be formed. It is also preferable to reduce the oxygen concentration in the surrounding atmosphere by replacing with nitrogen when applying the coating solution by spray coating and when drying by touch.

  The crosslinked surface layer preferably further contains an organic filler or an inorganic filler mentioned below. When the crosslinked surface layer contains a filler, the wear resistance of the electrostatic latent image carrier can be improved. Moreover, by including a filler, fine irregularities are formed on the surface of the crosslinked surface layer. Therefore, it is preferable because the lubricant is easily applied to the electrostatic latent image carrier.

  Although it does not specifically limit as an organic filler, Fluororesin, such as polytetrafluoroethylene, silicone resin, amorphous carbon, etc. can be used. These may be used alone or in combination of two or more.

  The inorganic filler is not particularly limited, but metal such as copper, tin, aluminum and indium, metal oxide such as silicon oxide, tin oxide, aluminum oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide and bismuth oxide, Potassium titanate or the like can be used. These may be used alone or in combination of two or more.

  The filler described above is preferably an inorganic filler from the viewpoint of hardness, and among the inorganic fillers, it is preferable to use a metal oxide from the viewpoint of electrostatic characteristics. Furthermore, among metal oxides, it is preferable to use silicon oxide (colloidal silica), aluminum oxide (colloidal alumina), and titanium oxide.

  The average primary particle size of the filler is preferably 0.01 to 0.5 μm. When the average primary particle size of the filler is less than 0.01 μm, the wear resistance of the electrostatic latent image carrier may be lowered. On the other hand, when the average primary particle size of the filler exceeds 0.5 μm, the light transmittance of the crosslinked surface layer may be lowered.

  The filler content in the crosslinked surface layer is usually 5 to 50% by mass, preferably 5 to 30% by mass. When the content of the filler in the crosslinked surface layer is less than 5% by mass, the wear resistance of the electrostatic latent image carrier may be lowered. On the other hand, when the filler content in the crosslinked surface layer exceeds 30% by mass, the electrostatic characteristics may be deteriorated. In addition, the light transmittance of the crosslinked surface layer may decrease.

  In addition, the filler may be surface-treated with a surface treatment agent. Thereby, the dispersibility of the filler in a bridge | crosslinking surface layer can be improved. Although it does not specifically limit as a surface treating agent, Titanate coupling agent, aluminum coupling agent, zircoaluminate coupling agent, higher fatty acid, aluminum oxide, titanium dioxide, zirconium dioxide, silicone resin, aluminum stearate, etc. Can be used. These may be used alone or in combination of two or more.

  Content of a surface treating agent is 3-30 mass% normally with respect to a filler, and it is preferable that it is 5-20 mass%. When content of a surface treating agent is less than 3 mass% with respect to a filler, the dispersibility of the filler in a bridge | crosslinking surface layer may deteriorate. On the other hand, when the content of the surface treatment agent exceeds 30% by mass with respect to the filler, the electrostatic characteristics of the electrostatic latent image carrier may deteriorate.

  Next, other structures of the electrostatic latent image carrier of the present invention will be described in detail.

≪Multi-layer type≫
In the multilayer type, the electrostatic latent image carrier has a support, a charge generation layer (CGL), and a charge transport layer (CTL) sequentially stacked on the support to provide a stacked photosensitive layer.

[Charge generation layer]
The charge generation layer contains a charge generation material and may contain a binder resin and other components. The charge generating substance is not particularly limited, and examples of the inorganic material include crystalline selenium, amorphous selenium, selenium-tellurium compound, selenium-tellurium-halogen compound, selenium-arsenic compound, and the like. As the charge generation material, organic materials include phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, azulenium salt pigments, squaric acid methine pigments, azo pigments having a carbazole skeleton, azo pigments having a triphenylamine skeleton, diphenylamine Azo pigments having a skeleton, azo pigments having a dibenzothiophene skeleton, azo pigments having a fluorenone skeleton, azo pigments having an oxadiazole skeleton, azo pigments having a bis-stilbene skeleton, azo pigments having a distyryloxadiazole skeleton, di An azo pigment having a styrylcarbazole skeleton, a perylene pigment, an anthraquinone pigment or a polycyclic quinone pigment, a quinoneimine pigment, a diphenylmethane or triphenylmethane pigment, a benzoquinone or a naphthoquinone pigment Cyanine and azomethine pigments, indigoid pigments, bisbenzimidazole pigments, and the like. These may be used alone or in combination of two or more.

  The binder resin contained in the charge generation layer is not particularly limited, but polyamide resin, polyurethane resin, epoxy resin, polyketone resin, polycarbonate resin, silicone resin, acrylic resin, polyvinyl butyral resin, polyvinyl formal resin, polyvinyl ketone resin, polystyrene Resin, poly-N-vinylcarbazole resin, polyacrylamide resin, and the like. These may be used alone or in combination of two or more.

  The charge generation layer may include a charge transport material. The charge generation layer may contain a polymer charge transport material as a binder resin.

  As a method for forming the charge generation layer, a glow discharge polymerization method, a vacuum deposition method, a CVD method, a sputtering method, a reactive sputtering method, an ion plating method, an accelerated ion injection method and the like, a dip coating method, Examples thereof include casting methods such as spray coating and bead coating. The vacuum thin film manufacturing method can satisfactorily form the inorganic material or organic material of the charge generation material described above.

  Solvents contained in the coating solution used when forming the charge generation layer using the casting method include acetone, methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, dichloroethane, dichloropropane, and trichloroethane. , Trichloroethylene, tetrachloroethane, tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, isopropyl alcohol, butanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosolve, ethyl cellosolve, propyl cellosolve, etc. Good. Among these, tetrahydrofuran, methyl ethyl ketone, dichloromethane, methanol, and ethanol having a boiling point of 40 to 80 ° C. are preferable from the viewpoint of the drying property of the coating film.

  The coating solution can be prepared by dissolving or dispersing the charge generation material in a solvent.

  Examples of the method for dissolving or dispersing the charge generating substance in the solvent include a method using a dispersion medium such as a ball mill, a bead mill, a sand mill, and a vibration mill, and a high-speed liquid collision dispersion method.

  Electrophotographic characteristics such as photosensitivity greatly depend on the thickness of the charge generation layer. The thickness of the charge generation layer is usually from 0.01 to 5 μm, and preferably from 0.05 to 2 μm.

[Charge transport layer]
When the electrostatic latent image carrier having the outermost surface layer as the charge transport layer is used, the charge transport layer is a crosslinked film having the aforementioned crosslinked surface layer. In this case, the wear resistance of the charge transport layer may be low, but it is preferable that the electric resistance of the charge transport layer is high in order to retain a charged charge. Further, in order to obtain a high surface potential by the charged charge to be held, it is preferable that the charge transport layer has a small dielectric constant and good charge mobility.

  The charge transport layer mainly includes a charge transport material and a binder resin. As the charge transport material, a low molecular charge transport material such as a hole transport material or an electron transport material can be used, and a polymer charge transport material may be added as necessary.

  As the hole transport material of the charge transport material, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, 9- (p-diethylaminostyrylanthracene), 1,1-bis- (4-dibenzylaminophenyl) ) Propane, styrylanthracene, styrylpyrazoline, phenylhydrazones, α-phenylstilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, thiophene derivatives, and the like. These may be used alone or in combination of two or more.

  As the polymer charge transport material, the following compounds can be used.

(A) Polymer having carbazole ring For example, poly-N-vinylcarbazole, JP-A-50-82056, JP-A-54-9632, JP-A-54-11737, JP-A-4-175337 And the compounds described in JP-A-4-183719 and JP-A-6-234841.

(B) Polymer having a hydrazone structure For example, JP-A-57-78402, JP-A-61-20953, JP-A-61-296358, JP-A-1-134456, JP-A-1-134456 179164, JP-A-3-180851, JP-A-3-180852, JP-A-3-50555, JP-A-5-310904, JP-A-6-234840, and the like. Is done.

(C) Polysilylene polymer For example, JP-A-63-285552, JP-A-1-88461, JP-A-4-264130, JP-A-4-264131, JP-A-4-264132, Examples thereof include compounds described in Kaihei 4-264133 and JP-A-4-289867.

(D) Polymer having a triarylamine structure For example, N, N-bis (4-methylphenyl) -4-aminopolystyrene, JP-A-1-134457, JP-A-2-282264, JP-A-2- Examples include compounds described in JP-A-304456, JP-A-4-133605, JP-A-4-133066, JP-A-5-40350, and JP-A-5-202135.
Is done.

(E) Other polymers For example, formaldehyde condensation polymer of nitropyrene, JP-A-51-73888, JP-A-56-150749, JP-A-6-234836, JP-A-6-234837 The described compounds and the like are exemplified.

  Other polymer charge transport materials include, for example, polycarbonate resins having a triarylamine structure, polyurethane resins having a triarylamine structure, polyester resins having a triarylamine structure, polyether resins having a triarylamine structure, Etc.

  Examples of such a polymer charge transporting material include JP-A 64-1728, JP-A 64-13061, JP-A 64-19049, JP-A-4-11627, JP-A 4-116627. JP 2225014, JP 4-230767, JP 4-320420, JP 5-232727, JP 7-56374, JP 9-127713, JP 9-222740. And compounds described in JP-A-9-265197, JP-A-9-211877, JP-A-9-30495, and the like.

  The polymer having an electron donating group may be a copolymer with a known monomer, a block polymer, a graft polymer, a star polymer, or the like. Further, as the polymer having an electron donating group, a cross-linked polymer having an electron donating group as disclosed in JP-A-3-109406 can be used.

  As the electron transport material of the charge transport material, a known one can be selected and used by those skilled in the art. Specifically, a fluorene compound or a quinone compound can be used, and these may be used alone or in combination of two or more.

  The charge transport layer may contain a binder resin. Examples of the binder resin include polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyethylene resin, polyvinyl chloride resin, polyvinyl acetate resin, polystyrene resin, phenol resin, epoxy resin, polyurethane resin, polyvinylidene chloride resin, and alkyd. Resins, silicone resins, polyvinyl carbazole resins, polyvinyl butyral resins, polyvinyl formal resins, polyacrylate resins, polyacrylamide resins, phenoxy resins, and the like are used. These may be used alone or in combination of two or more.

  The charge transport layer may be formed by crosslinking a crosslinkable binder resin and a crosslinkable charge transport material.

  The charge transport layer may be formed by crosslinking a crosslinkable binder resin and a crosslinkable charge transport material.

  The charge transport layer can be formed by applying a coating solution in which a charge transport material and a binder resin are dissolved or dispersed in a solvent on the charge generation layer.

  The charge transport layer may further contain a plasticizer, an antioxidant, a leveling agent and the like.

  The thickness of the charge transport layer is usually 5 to 100 μm, and 5 to 30 μm is preferable in order to achieve high image quality of 1200 dpi or more.

≪Single layer type≫
In the single-layer type photosensitive layer, the electrostatic latent image carrier has a single-layer type photosensitive layer on the support.

  When the single-layer type photosensitive layer uses the electrostatic latent image bearing member of the outermost surface layer, the photosensitive layer has a crosslinked film having the aforementioned crosslinked surface layer. In this case, the abrasion resistance of the photosensitive layer may be low. The photosensitive layer may contain a charge generation material, a charge transport material, a binder resin, and other components.

  A single-layer type photosensitive layer, for example, can be formed by dissolving or dispersing a charge generating substance, a binder resin, and a charge transporting substance in a suitable solvent, and applying and drying them (casting method). The single-layer photosensitive layer may contain a plasticizer.

  The thickness of the single-layer type photosensitive layer is usually 5 to 100 μm, preferably 5 to 50 μm. When the thickness of the single-layer type photosensitive layer is less than 5 μm, the chargeability may be lowered. When the thickness of the single-layer type photosensitive layer exceeds 100 μm, the sensitivity may be lowered.

≪Support body≫
The support in the photoreceptor is not particularly limited as long as it has a conductivity of 10 ¹⁰ Ω · cm or less, and can be appropriately selected by those skilled in the art according to the purpose.

  Specifically, as the material of the support, a metal such as Al, Ni, Cr, Cu, Au, Ag, Pt, or an alloy thereof; a metal oxide such as tin oxide or indium oxide is deposited or sputtered, Film or cylindrical plastic, paper-coated; aluminum, aluminum alloy, nickel, stainless steel, etc. or surface treatment such as cutting, super-finishing, polishing, etc. And the like. Further, endless nickel belts and endless stainless steel belts disclosed in JP-A-52-36016 can also be used. Furthermore, a nickel foil with a thickness of 50 μm to 150 μm may be used, or a surface of a polyethylene terephthalate film with a thickness of 50 μm to 150 μm may be subjected to conductive processing such as aluminum vapor deposition. Furthermore, a material obtained by dispersing conductive powder in a binder resin and coating the above-mentioned support may be used.

  Examples of the conductive powder include carbon black, acetylene black; metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, and silver; metal oxide powder such as conductive tin oxide and ITO; It is done. As the binder resin, polystyrene resin, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester resin, polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer , Polyvinyl acetate resin, polyvinylidene chloride resin, polyarylate resin, phenoxy resin, polycarbonate resin, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral resin, polyvinyl formal resin, polyvinyl toluene resin, poly-N-vinyl carbazole, acrylic resin, Silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin and the like can be mentioned.

  As a method of coating the conductive powder dispersed in a binder resin, the conductive powder and the binder resin described above are dispersed in a solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, toluene, and applied. Can be formed.

  In addition, it is conductive by a heat-shrinkable tube containing the above conductive powder on a cylindrical substrate such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, and Teflon (registered trademark). A conductive layer may be provided as a support.

<< Underlayer >>
The undercoat layer is provided for the purpose of improving adhesiveness, preventing moire, improving the coatability of the upper layer, and reducing the residual potential.

  The subbing layer is preferably a resin having high resistance to dissolution in an organic solvent in consideration of application of a coating solution when forming a charge generation layer or a photosensitive layer. For example, water-soluble resins such as polyvinyl alcohol, casein, sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, alkyd-melamine resin, epoxy resin, etc. Examples include curable resins to be formed. Further, fine powders such as metal oxides exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like, or metal sulfides and metal nitrides may be added.

  The undercoat layer can be formed by a coating method or the like.

  Moreover, as the undercoat layer, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, etc. are used, a metal oxide formed by a sol-gel method, an aluminum oxide formed by anodization, Polyparaxylylene (parylene), tin (IV) oxide formed by a vacuum thin film manufacturing method, titanium dioxide, ITO, cerium oxide, or the like may be used.

  The thickness of the undercoat layer is usually 0.1 to 10 μm, and preferably 1 to 5 μm.

  In addition, an antioxidant may be added to each layer such as a photosensitive layer, a crosslinked surface layer, a charge transport layer, a charge generation layer, an undercoat layer, or an intermediate layer for the purpose of preventing a decrease in sensitivity and an increase in residual potential. good.

[Image forming apparatus]
The image forming apparatus of the present invention will be described with reference to the drawings. The image forming apparatus of the present invention includes an electrostatic latent image carrier, a charging unit for charging the electrostatic latent image carrier, an exposure unit for exposing the charged electrostatic latent image carrier to form an electrostatic latent image, Developing means for developing the electrostatic latent image formed on the latent image carrier with toner to form a toner image, and transfer means for transferring the toner image formed on the electrostatic latent image carrier to a recording medium.

  FIG. 5 is a schematic view showing an example of the image forming apparatus of the present invention. The image forming apparatus 100A includes a drum-shaped photoconductor (electrostatic latent image carrier) 10 and is driven to rotate counterclockwise, for example.

  Hereinafter, a method of forming an image using the image forming apparatus 100A will be described, but the present invention is not limited in this respect. After neutralizing the surface of the photoconductor 10 with the neutralizing lamp 101, the surface of the photoconductor 10 is charged with the charger 102. Next, an exposure device (not shown) irradiates the surface of the photoconductor 10 with exposure light L to form an electrostatic latent image. Thereafter, the developing unit 103 develops the electrostatic latent image with toner to form a toner image. Further, after the toner image formed on the surface of the photoconductor 10 is charged by the pre-transfer charger 104, the toner image is transferred to the recording paper P supplied from the registration roller 105 by the transfer charger 106. Next, after the recording paper P on which the toner image has been transferred is charged by the separation charger 107, the recording paper P is separated from the photoreceptor 10 by the separation claw 108. On the other hand, after the toner remaining on the surface of the photoconductor 10 is charged by the pre-cleaning charger 109, the toner remaining on the surface of the photoconductor 10 is removed by the cleaning brush 110 and the cleaning blade 111.

  As the light source of the static elimination lamp 101 and the exposure device, a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), an electroluminescence (EL), or the like can be used. At this time, a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, a color temperature conversion filter, or the like may be used to irradiate light in a desired wavelength range.

  As the charger 102, the pre-transfer charger 104, the transfer charger 106, the separation charger 107, and the pre-cleaning charger 109, a corotron, a scorotron, a solid charger (solid state charger), a charging roller, or the like is used. Can do.

  When a corotron or scorotron charger is used as a charger, in an image forming apparatus equipped with a conventional photoconductor having a crosslinked surface layer, the resistance of the surface of the photoconductor near the charger is reduced by a low-resistance substance released from the charger. The value sometimes dropped. As a result, when the apparatus is restarted, the charging potential and the post-exposure potential are lowered, and strip-like density unevenness in the width of the charger may occur. However, in the image forming apparatus of the present invention, since the electrostatic latent image carrier according to the present invention is used, the low-resistance substance does not easily penetrate the cross-linked surface layer, the surface resistance is difficult to drop, and the strip-shaped density unevenness. It is the structure which is hard to generate.

  In addition, in the case where a charge transport layer is provided below the cross-linked surface layer, if the charge transport layer contains a charge transport material having a low ionization potential, image blur and residual potential increase may be caused. However, in the image forming apparatus having the electrostatic latent image carrier according to the present invention, occurrence of abnormal images such as image blur is suppressed. This is considered to be because the oxidizing gas generated by the discharge of the charger is difficult to permeate the surface layer.

  The lubricant application brush 110 is not particularly limited, and a fur brush, a mag fur brush, or the like can be used.

  The material of the cleaning blade 111 is not particularly limited, and examples thereof include urethane resin, silicone resin, fluorine resin, urethane elastomer, silicone elastomer, and fluorine elastomer. Among these, it is preferable to use urethane elastomer from the point of abrasion resistance, ozone resistance, and contamination resistance.

  The cleaning blade 111 preferably has a hardness (JIS-A) of 65 to 85 degrees. Moreover, it is preferable that the cleaning blade 111 normally has a thickness of 0.8 to 3.0 mm and a protrusion amount of 3 to 15 mm.

  The toner is not particularly limited, and for example, a toner obtained by adding an external additive to base particles containing a binder resin and a colorant can be used. At this time, the base particles may contain other components such as a release agent and a charge control agent.

  FIG. 6 shows a schematic diagram of another example of the image forming apparatus of the present invention. The image forming apparatus 100 </ b> B includes a belt-shaped photoconductor (electrostatic latent image carrier) 10 and is stretched by a driving roller 121 and driven rollers 122 and 123. The photosensitive member (electrostatic latent image carrier) 10 is driven to rotate, for example, clockwise by a driving roller 121.

  Although a method of forming an image using the image forming apparatus 100B will be described, the present invention is not limited in this respect. After neutralizing the surface of the belt-shaped photoconductor 10 with the neutralizing lamp 101, the surface of the photoconductor 10 is charged with the charger 102. Next, an exposure device (not shown) irradiates the surface of the photoconductor 10 with exposure light L to form an electrostatic latent image. Thereafter, the developing unit 103 develops the electrostatic latent image with toner to form a toner image. Further, after the toner image is transferred to a recording paper (not shown) by the transfer charger 106, the toner remaining on the surface of the photoconductor 10 is removed by the cleaning brush 110 and the cleaning blade 111. Further, the toner remaining on the surface of the photoreceptor 10 is removed by the cleaning brush 124.

  The cleaning brush 124 having the same configuration as that of the cleaning brush 110 can be used.

[Process cartridge]
The process cartridge of the present invention has a photosensitive member (electrostatic latent image carrier), integrally supports a charging unit, a developing unit, and a cleaning unit, and is detachable from the main body of the image forming apparatus.

  FIG. 7 shows an example of the process cartridge of the present invention. The process cartridge 200 includes a photoreceptor 10, a charger 102, a developing device 103, a cleaning brush 110, and a cleaning blade 111, and further includes other means as necessary. Reference numeral 203 denotes an exposure unit (latent image forming unit), 205 denotes a recording medium, and 210 denotes a conveyance roller.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to an Example. In addition, a part means a mass part.

[Example 1]
The following undercoat layer coating solution was applied to an aluminum support (outer diameter: 100 mmφ) by an immersion method to form an undercoat layer. The thickness of the undercoat layer after drying at 130 ° C. for 20 minutes was 3.5 μm.

Undercoat layer coating solution (solvent: methyl ethyl ketone):
6 parts of alkyd resin (Beckolite M6401-50, manufactured by Dainippon Ink and Chemicals);
Melamine resin (Super Becamine G-821-60, manufactured by Dainippon Ink & Chemicals, Inc.)
4 parts;
40 parts of titanium oxide (CR-EL, manufactured by Ishihara Sangyo);
On the obtained undercoat layer, the following charge generation layer coating solution was dip coated to form a charge generation layer. The film thickness of the charge generation layer after drying at 130 ° C. for 20 minutes was 0.2 μm.

Coating solution for charge generation layer:
6 parts Y-type titanyl phthalocyanine;
4 parts of butyral resin BX-1 (Sekisui Chemical Co., Ltd.);
2-butanone (manufactured by Kanto Chemical) 200 parts;
On the resulting charge generation layer, the following charge transport layer coating solution was dip coated to form a charge transport layer. The film thickness of the charge transport layer after drying at 135 ° C. for 20 minutes was 22 μm.

Coating liquid for charge transport layer:
10 parts of bisphenol Z type polycarbonate;
10 parts of a low molecular charge transport material of the following structural formula (7);

テトラヒドロフラン８０部；
得られた電荷輸送層上に、下記の架橋表面層用塗工液を窒素気流中でスプレー塗工後、１０分間窒素気流中に放置して指触乾燥した。その後、酸素濃度が２％以下となるようにブース内を窒素ガスで置換したＵＶ照射ブースにて、光照射を行った。

80 parts of tetrahydrofuran;
On the obtained charge transport layer, the following coating solution for a cross-linked surface layer was spray-coated in a nitrogen stream, and then left in a nitrogen stream for 10 minutes to dry the touch. Thereafter, light irradiation was performed in a UV irradiation booth in which the inside of the booth was replaced with nitrogen gas so that the oxygen concentration was 2% or less.

Furthermore, it was dried at 130 ° C. for 20 minutes to obtain an electrostatic latent image carrier of Example 1. The film thickness of the surface cross-linked layer was 8 μm.
Light irradiation conditions:
Metal halide lamp, 160 W / cm;
Irradiation distance, 120 mm;
Irradiation intensity, 700 mW / cm ² ;
Irradiation time, 80 seconds;
Crosslinked surface layer coating solution:
Exemplified compound No. 1 in Table 1 3 parts of a monofunctional radically polymerizable compound of I-2 (SR339A, manufactured by Sartomer, acrylic equivalent 192);
5 parts of trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku Co., Ltd., acrylic equivalent 99, trifunctional or higher functional radical polymerizable compound having no charge transporting structure);
2 parts of dipentaerythritol caprolactone-modified hexaacrylate (KAYARAD DPCA-120, manufactured by Nippon Kayaku Co., Ltd., acrylic equivalent 324);
10 parts of a radically polymerizable compound (acryl equivalent 420) having a monofunctional charge transport structure of the following structural formula (8);

表２の例示化合物Ｎｏ．ＩＩ−１に示したオキサゾール化合物０．５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１８４、チバ・スペシャルティ・ケミカルズ製、光重合開始剤）１部；
テトラヒドロフラン１００部；
である。

Exemplified Compound Nos. 0.5 part of the oxazole compound shown in II-1;
1 part of 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals, photopolymerization initiator);
100 parts of tetrahydrofuran;
It is.

[Example 2]
As the oxazole compound, Exemplified Compound Nos. In place of II-1, Exemplified Compound Nos. An electrostatic latent image carrier of Example 2 was obtained by the same process as Example 1 except that II-4 was used.

[Example 3]
As the oxazole compound, Exemplified Compound Nos. In place of II-1, Exemplified Compound Nos. An electrostatic latent image carrier of Example 3 was obtained in the same manner as in Example 1 except that II-6 was used.

[Example 4]
As the oxazole compound, Exemplified Compound Nos. In place of II-1, Exemplified Compound Nos. An electrostatic latent image carrier of Example 4 was obtained by the same process as Example 1 except that II-7 was used.

[Example 5]
As the oxazole compound, Exemplified Compound Nos. In place of II-1, Exemplified Compound Nos. An electrostatic latent image carrier of Example 5 was obtained by the same process as Example 1 except that II-10 was used.

[Example 6]
As the oxazole compound, Exemplified Compound Nos. In place of II-1, Exemplified Compound Nos. An electrostatic latent image carrier of Example 6 was obtained by the same process as Example 1 except that II-12 was used.

[Example 7]
As the monofunctional radically polymerizable compound, Exemplified Compound Nos. Instead of I-2, Exemplified Compound Nos. An electrostatic latent image carrier of Example 7 was obtained by the same process as Example 1 except that I-3 (Aronix M-101A, manufactured by Toagosei Co., Ltd., acrylic equivalent 236) was used.

[Example 8]
As the monofunctional radically polymerizable compound, Exemplified Compound Nos. Instead of I-2, Exemplified Compound Nos. An electrostatic latent image carrier of Example 8 was obtained by the same process as Example 1 except that I-7 (Aronix M-5700, manufactured by Toagosei Co., Ltd., acrylic equivalent 222) was used.

[Example 9]
As the oxazole compound, Exemplified Compound Nos. In place of II-1, Exemplified Compound Nos. An electrostatic latent image carrier of Example 9 was obtained in the same manner as in Example 1, except that II-6 was used and the addition amount was changed to 0.03 parts by mass.

[Example 10]
Exemplified Compound Nos. An electrostatic latent image carrier of Example 10 was obtained in the same manner as in Example 9, except that the amount of II-6 added was changed to 0.05 parts by mass.

[Example 11]
Exemplified Compound Nos. An electrostatic latent image carrier of Example 11 was obtained in the same manner as in Example 9, except that the amount of II-6 added was changed to 1 part by mass.

[Example 12]
Exemplified Compound Nos. An electrostatic latent image carrier of Example 12 was obtained in the same manner as in Example 9, except that the amount of II-6 added was changed to 1.2 parts by mass.

[Example 13]
Exemplified Compound Nos. An electrostatic latent image carrier of Example 13 was obtained in the same manner as in Example 9, except that the amount of II-6 added was changed to 1.5 parts by mass.

[Example 14]
The same steps as in Example 1 except that the content of the monofunctional radically polymerizable compound in Example 1 was changed to the following and the radically polymerizable compound having a monofunctional charge transporting structure was changed to the compound shown below. Thus, an electrostatic latent image bearing member of Example 14 was obtained.
The content of the monofunctional radically polymerizable compound is:
Exemplified compound No. 1 in Table 1 2 parts of a monofunctional radically polymerizable compound of I-2 (SR339A, manufactured by Sartomer, acrylic equivalent 192);
5 parts of trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku Co., Ltd., acrylic equivalent 99, trifunctional or higher functional radical polymerizable compound having no charge transporting structure);
3 parts of dipentaerythritol caprolactone modified hexaacrylate (KAYARAD DPCA-120, Nippon Kayaku acrylic equivalent: 324);
And
The radical polymerizable compound having a monofunctional charge transport structure is:
10 parts of a radical polymerizable compound (acryl equivalent 448) having a monofunctional charge transporting structure represented by the following structural formula (9) was used.

［実施例１５］
実施例３の各化合物の含有量を、以下に変更した以外は、実施例３と同様の工程により、実施例１５の静電潜像担持体を得た。
表１の例示化合物Ｎｏ．Ｉ−２の単官能ラジカル重合性化合物（ＳＲ３３９Ａ；サートマー製 アクリル当量：１９２）４部；
トリメチロールプロパントリアクリレート（ＫＡＹＡＲＡＤ ＴＭＰＴＡ、日本化薬製、アクリル当量９９、電荷輸送性構造を有さない３官能以上のラジカル重合性化合物）４部；
ジペンタエリスリトールカプロラクトン変性ヘキサアクリレート（ＫＡＹＡＲＡＤ ＤＰＣＡ−１２０、日本化薬製、アクリル当量３２４）２部；
１官能の電荷輸送性構造を有するラジカル重合性化合物は、
実施例１４の構造式（９）の１官能の電荷輸送性構造を有するラジカル重合性化合物（アクリル当量４４８）１０部を用いた。

[Example 15]
An electrostatic latent image carrier of Example 15 was obtained in the same manner as in Example 3, except that the content of each compound of Example 3 was changed to the following.
Exemplified compound No. 1 in Table 1 4 parts of a monofunctional radically polymerizable compound of I-2 (SR339A; manufactured by Sartomer, acrylic equivalent: 192);
4 parts of trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku Co., Ltd., acrylic equivalent 99, trifunctional or higher functional radical compound having no charge transporting structure);
2 parts of dipentaerythritol caprolactone-modified hexaacrylate (KAYARAD DPCA-120, manufactured by Nippon Kayaku Co., Ltd., acrylic equivalent 324);
The radical polymerizable compound having a monofunctional charge transport structure is:
10 parts of a radical polymerizable compound (acryl equivalent 448) having a monofunctional charge transporting structure represented by the structural formula (9) in Example 14 was used.

[Example 16]
An electrostatic latent image carrier of Example 16 was obtained in the same manner as in Example 3, except that the content of each compound of Example 3 was changed to the following.
Exemplified compound No. 1 in Table 1 7 parts of I-2 (SR339A, manufactured by Sartomer, acrylic equivalent 192);
2 parts of trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku Co., Ltd., acrylic equivalent 99, trifunctional or higher functional radical compound having no charge transporting structure);
1 part of dipentaerythritol caprolactone-modified hexaacrylate (KAYARAD DPCA-120, manufactured by Nippon Kayaku Co., Ltd., acrylic equivalent 324);
The radical polymerizable compound having a monofunctional charge transport structure is:
10 parts of a radical polymerizable compound (acryl equivalent 448) having a monofunctional charge transporting structure represented by the structural formula (9) in Example 14 was used.

[Example 17]
An electrostatic latent image carrier of Example 17 was obtained in the same manner as in Example 3, except that the content of each compound of Example 3 was changed to the following.
Exemplified compound No. 1 in Table 1 I-2 (SR339A, manufactured by Sartomer, acrylic equivalent 192) 8 parts;
1 part of trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku Co., Ltd., acrylic equivalent 99, trifunctional or higher functional radical compound having no charge transporting structure);
1 part of dipentaerythritol caprolactone-modified hexaacrylate (KAYARAD DPCA-120, manufactured by Nippon Kayaku Co., Ltd., acrylic equivalent 324);
The radical polymerizable compound having a monofunctional charge transport structure is:
10 parts of a radically polymerizable compound (acryl equivalent 184) having a monofunctional charge transporting structure represented by the following structural formula (10) was used.

［実施例１８］
実施例３の電荷輸送性構造を有さない３官能以上のラジカル重合性化合物のうち、ジペンタエリスリトールカプロラクトン変性ヘキサアクリレートを、表３の例示化合物Ｎｏ．ＩＩＩ−１に変更した以外は、実施例３と同様の工程により実施例１８の静電潜像担持体を得た。表３の例示化合物Ｎｏ．ＩＩＩ−１（ＳＲ４１５、エトキシ化トリメチロールプロパントリアクリレート、サートマー製、アクリル当量４０７）を用いた。

[Example 18]
Of the trifunctional or higher functional radical polymerizable compounds having no charge transporting structure of Example 3, dipentaerythritol caprolactone-modified hexaacrylate was converted to Exemplified Compound No. 1 in Table 3. An electrostatic latent image carrier of Example 18 was obtained in the same manner as in Example 3 except for changing to III-1. Exemplified Compound Nos. III-1 (SR415, ethoxylated trimethylolpropane triacrylate, manufactured by Sartomer, acrylic equivalent 407) was used.

[Example 19]
Of the trifunctional or higher functional radical polymerizable compounds having no charge transporting structure of Example 3, dipentaerythritol caprolactone-modified hexaacrylate was converted to Exemplified Compound No. 1 in Table 3. An electrostatic latent image carrier of Example 19 was obtained in the same manner as in Example 3, except that the change was made to III-2. Exemplified Compound Nos. III-2 (SR9035, ethoxylated trimethylolpropane triacrylate, manufactured by Sartomer, acrylic equivalent 319) was used.

[Example 20]
Of the trifunctional or higher functional radical polymerizable compounds having no charge transport structure of Example 3, dipentaerythritol caprolactone-modified hexaacrylate was changed to the following radical polymerizable compound, and was the same as Example 3. The electrostatic latent image carrier of Example 20 was obtained by the process. Dipentaerythritol caprolactone-modified hexaacrylate (KAYARAD DPCA-60, Nippon Kayaku Co., Ltd., acrylic equivalent 211) was used.

[Example 21]
Of the trifunctional or higher functional radical polymerizable compounds having no charge transport structure of Example 3, dipentaerythritol caprolactone-modified hexaacrylate was changed to the following radical polymerizable compound, and was the same as Example 3. The electrostatic latent image carrier of Example 21 was obtained according to the process.
Ditrimethylolpropane tetraacrylate (SR355, manufactured by Sartomer, acrylic equivalent 117) was used.

[Example 22]
Similar to the electrostatic latent image carrier of Example 1, an undercoat layer, a charge generation layer, and a charge transport layer were sequentially laminated on an aluminum support.

  On the obtained charge transport layer, the following coating solution for a cross-linked surface layer was spray-coated in a nitrogen stream, and then left in a nitrogen stream for 10 minutes to dry the touch. Thereafter, light irradiation was performed in a UV irradiation booth in which the inside of the booth was replaced with nitrogen gas so that the oxygen concentration was 2% or less.

Furthermore, it was dried at 130 ° C. for 20 minutes to obtain an electrostatic latent image carrier of Example 22. The film thickness of the surface cross-linked layer was 4 μm.
Light irradiation conditions:
Metal halide lamp, 160 W / cm;
Irradiation distance, 120 mm;
Irradiation intensity, 700 mW / cm ² ;
Irradiation time, 100 seconds;
Crosslinked surface layer coating solution:
Exemplified compound No. 1 in Table 1 3 parts of a monofunctional radically polymerizable compound of I-2 (SR339A, manufactured by Sartomer, acrylic equivalent 192);
5 parts of trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku Co., Ltd., acrylic equivalent 99, trifunctional or higher functional radical polymerizable compound having no charge transporting structure);
2 parts of dipentaerythritol caprolactone-modified hexaacrylate (KAYARAD DPCA-120, manufactured by Nippon Kayaku Co., Ltd., acrylic equivalent 324);
10 parts of a radically polymerizable compound having a monofunctional charge transport structure of the structural formula (9) of Example 14 (acryl equivalent 448);
Exemplified Compound Nos. 0.5 part of an oxazole compound shown in II-6;
3 parts of alumina fine particles (AA-03, average primary particle size 0.3 μm, manufactured by Sumitomo Chemical);
0.06 part of unsaturated polycarboxylic acid polymer BYK-P104 (manufactured by BYK Chemie) was used.

[Example 23]
The same procedure as in Example 22 was followed except that a coating solution for a crosslinked surface layer was prepared using silica KMPX100 (manufactured by Shin-Etsu Chemical Co., Ltd.) having an average primary particle size of 0.1 μm instead of alumina AA-03. Thus, an electrostatic latent image carrier of Example 23 was obtained.

[Example 24]
The same as in Example 22 except that a coating solution for a crosslinked surface layer was prepared using titanium oxide CR-97 (manufactured by Ishihara Sangyo Co., Ltd.) having an average primary particle size of 0.25 μm instead of alumina AA-03. According to the process, an electrostatic latent image carrier of Example 24 was obtained.

[Example 25]
Instead of alumina AA-03 (manufactured by Sumitomo Chemical Co., Ltd.), PTFE fine particles (Mitsui / DuPont Fluorochemical) having an average primary particle size of 0.25 μm were used to prepare a coating solution for a crosslinked surface layer. The electrostatic latent image bearing member of Example 25 was obtained through the same steps as in Example 22.

[Comparative Example 1]
An electrostatic latent image carrier of Comparative Example 1 was obtained by the same process as Example 1 except that the oxazole compound was not used.

[Comparative Example 2]
An electrostatic latent image carrier of Comparative Example 2 was obtained by the same process as in Example 7 except that the oxazole compound was not used.

[Comparative Example 3]
An electrostatic latent image carrier of Comparative Example 3 was obtained by the same process as Example 8 except that the oxazole compound was not used.

[Comparative Example 4]
An electrostatic latent image carrier of Comparative Example 4 was obtained in the same manner as in Example 1 except that an ultraviolet absorber (UV-1) represented by the following structural formula (11) was used instead of the oxazole compound.

［比較例５］
オキサゾール化合物の代わりに、下記構造式（１２）の紫外線吸収剤（ＵＶ−２）を使用した以外は、実施例１と同様の工程により、比較例５の静電潜像担持体を得た。

[Comparative Example 5]
An electrostatic latent image carrier of Comparative Example 5 was obtained in the same manner as in Example 1, except that an ultraviolet absorber (UV-2) represented by the following structural formula (12) was used instead of the oxazole compound.

［比較例６］
オキサゾール化合物の代わりに、下記構造式（１３）の１重項酸素クエンチャー（Ｑ−１）を使用した以外は、実施例１と同様の工程により、比較例６の静電潜像担持体を得た。

[Comparative Example 6]
The electrostatic latent image carrier of Comparative Example 6 was prepared in the same manner as in Example 1 except that the singlet oxygen quencher (Q-1) represented by the following structural formula (13) was used instead of the oxazole compound. Obtained.

［比較例７］
単官能ラジカル重合性化合物として、表１の例示化合物Ｎｏ．Ｉ−２の代わりに、ジペンタエリスリトールカプロラクトン変性ヘキサアクリレート （ＫＡＹＡＲＡＤ ＤＰＣＡ−１２０、日本化薬製 アクリル当量３２４）５部を用いた以外は、実施例３と同様の工程により、比較例７の静電潜像担持体を得た。

[Comparative Example 7]
As the monofunctional radically polymerizable compound, Exemplified Compound Nos. In the same manner as in Example 3, except that 5 parts of dipentaerythritol caprolactone-modified hexaacrylate (KAYARAD DPCA-120, Nippon Kayaku acrylic equivalent 324) was used instead of I-2, An electrostatic latent image carrier was obtained.

[Comparative Example 8]
Exemplified compound No. 1 in Table 1 The electrostatic latent image bearing member of Comparative Example 8 was prepared in the same manner as in Example 3 except that the monofunctional radical polymerizable compound of I-2 was changed to a monofunctional radical polymerizable compound of the following structural formula (14). Got.

構造式（１４）の単官能ラジカル重合性化合物は、アロニックスＭ１０２、東亞合成製、アクリル当量３２４である。

The monofunctional radically polymerizable compound of the structural formula (14) is Aronix M102, manufactured by Toagosei Co., Ltd., and has an acrylic equivalent of 324.

[Comparative Example 9]
Exemplified compound No. 1 in Table 1 The electrostatic latent image bearing member of Comparative Example 9 was prepared in the same manner as in Example 3 except that the monofunctional radical polymerizable compound of I-2 was changed to a monofunctional radical polymerizable compound of the following structural formula (15). Got.

構造式（１５）の単官能ラジカル重合性化合物は、アロニックスＭ１１１、東亞合成製、アクリル当量３１８である。

The monofunctional radically polymerizable compound of the structural formula (15) is Aronix M111, manufactured by Toagosei Co., Ltd., and has an acrylic equivalent of 318.

[Comparative Example 10]
Except that the trifunctional or higher functional radical polymerizable compound having no charge transporting structure was changed to a bifunctional radical polymerizable compound of the following structural formula (16), the same procedure as in Example 3 was followed. An electrostatic latent image carrier was obtained.

構造式（１６）の２官能ラジカル重合性化合物は、トリプロピレングリコールジアクリレート（ＳＲ３０６Ｈ、サートマー製、アクリル当量１５０）である。

The bifunctional radically polymerizable compound of the structural formula (16) is tripropylene glycol diacrylate (SR306H, manufactured by Sartomer, acrylic equivalent 150).

[Comparative Example 11]
An electrostatic latent image carrier of Comparative Example 11 was obtained in the same manner as in Example 3 except that the radical polymerizable compound having a monofunctional charge transporting structure was not used.

[Evaluation]
The following image evaluations were performed on the electrostatic latent image carriers of each Example and each Comparative Example.

≪Elastic displacement rate≫
In the present invention, the mechanical strength of the crosslinked surface layer was evaluated by an elastic displacement rate measured by a micro surface hardness tester.

  The elastic displacement rate τe can be measured by a load-unloading test of a micro surface hardness meter using a diamond indenter. FIG. 8 is a schematic diagram for explaining the method for measuring the elastic displacement rate of the crosslinked surface layer according to the present invention.

  As shown in FIG. 8, first, the indenter is brought into contact with the sample, and the indenter is pushed in at a constant load speed from the contact point (a) (loading process). Next, when reaching a preset set load, it stops at a maximum displacement (b) for a certain period of time, and then lifts the indenter at a constant unloading speed (unloading process). The point at which no load is finally applied to the indenter during unloading is defined as plastic displacement (c).

  FIG. 9 shows an example of a curve showing the relationship between the indentation depth and the load obtained by the measurement method with reference to FIG. As shown in FIG. 9, the maximum displacement (b) and the plastic displacement (c) elastic displacement rate τe are calculated by the following equation (I).

Elastic displacement rate τe (%) = [(maximum displacement) − (plastic displacement)] / (maximum displacement) × 100 Formula (I)
The measurement of the elastic displacement rate is usually performed under a constant temperature and humidity. In this embodiment, the elastic displacement rate was measured under environmental conditions of a temperature of 22 ° C. and a relative humidity of 55%. Usually, the greater the elastic displacement rate, the stronger the mechanical strength of the crosslinked surface layer and the higher the wear resistance.

  In the present embodiment, measurement was performed using a microhardness measurement system H-100 (Fischer Instruments) and a Vickers indenter, but the present invention is not limited to this as long as the elastic displacement rate can be measured.

  Further, the elastic displacement rate τe was measured at an arbitrary five points on the sample and calculated as an average value of these five values. In the measurement, a photoconductor having the crosslinked surface layer of the present invention prepared on an aluminum cylinder was used. Since the elastic displacement rate τe is affected by the spring characteristics of the substrate, it is preferable to use a rigid metal plate, a slide glass, or the like as the substrate. In addition, since the hardness and elasticity factors of the lower layer of the crosslinked surface layer (for example, charge transport layer, charge generation layer, etc.) are also affected, the specified load is set so that the maximum displacement is 1/8 of the crosslinked surface layer thickness. It was adjusted. In the method of producing only the cross-linked surface layer alone on the substrate, the surface cross-linked layer of the electrostatic latent image carrier cannot be accurately reproduced due to the mixing of the lower layer components and the adhesion to the lower layer. It was adopted.

≪Exposure potential≫
The electrostatic latent image carriers obtained in Examples and Comparative Examples were mounted on a black station of a Ricoh full color printer RICOH Pro C900 modified machine. Thereafter, 200,000 A4-size halftone test charts with a black monochrome image area ratio of 5% were output, and then 50 solid images were output continuously. As the exposure portion potential VL, the solid portion potential of the 5th sheet of the 46th to 50th sheets at the time of continuous output of 50 sheets was measured, and the average value was adopted.

≪Evaluation of density unevenness≫
In an environment of 15 ° C. and 20% RH, an electrostatic latent image carrier was mounted on a black station of a Ricoh full color printer RICOH Pro C900 modified machine (installed as a charger that had been previously discharged for 200 hours or more). The image evaluation was performed under the following conditions.

  Continuously output 20,000 black monochrome test charts, and then turn off the power of the image forming apparatus main body. After the elapse of 24 hours, the image forming apparatus main body was turned on, and a 1200 dpi 2by2 black single-color whole surface halftone image was output, and the presence or absence of density unevenness corresponding to the width of the charger was evaluated.

Evaluation criteria are
A: Density unevenness does not occur,
○: Slight density unevenness occurred but practically acceptable level,
X: Density unevenness of the charger width is remarkably generated and is not acceptable.
It was.

≪Gas resistance evaluation≫
Using a NOx exposure tester (manufactured by Directec), after exposing the electrostatic latent image carrier for 72 hours in an atmosphere of NO / NO2 = 50/50 ppm, install it on the black station of the Ricoh full color printer RICOH Pro C900 remodeling machine. The presence or absence of occurrence of image blur was evaluated.

Evaluation criteria are
A: Image blur does not occur,
○: Image blurring slightly occurred but practically acceptable,
×: Unacceptable level in which the exposed part generates image blur
It was.

≪Durability evaluation≫
The electrostatic latent image carrier was mounted on a black station of a Ricoh full color printer RICOH Pro C900 remodeling machine in a normal temperature and humidity environment, and 200,000 continuous black test charts were output. The amount of wear on the surface layer was calculated from the film thickness of the electrostatic latent image carrier before and after continuous output. In addition, the scratches on the surface and the image density of the solid image after continuous output of 200,000 sheets were visually evaluated.

  Table 4 shows the evaluation results of each evaluation.

表４から、本発明の静電潜像担持体（感光体）は、濃度ムラ、ボケの発生が抑えられ、かつ十分な機械的耐久性を有する。また、電気特性に優れ、長期間の繰返し使用においても、良好な画像を出力し続けられることがわかった。

From Table 4, the electrostatic latent image carrier (photosensitive member) of the present invention is suppressed in density unevenness and blurring and has sufficient mechanical durability. Moreover, it was found that it has excellent electrical characteristics and can continue to output a good image even after repeated use over a long period of time.

DESCRIPTION OF SYMBOLS 10 Electrostatic latent image carrier 11 Support body 12 Photosensitive layer 13 Charge generation layer 14 Charge transport layer 15 Undercoat layer 16 Protective layer

JP 2006-099028 A

Claims (10)

In the electrostatic latent image carrier having a photosensitive layer on a conductive support, the surface of the photosensitive layer is
A monofunctional radically polymerizable compound represented by the following general formula (1) and having a molecular weight ratio of 300 or less to the number of radically polymerizable functional groups;
A tri- or higher functional radical polymerizable compound having no charge transporting structure;
A radically polymerizable compound having a charge transporting structure;
Having a crosslinked surface layer comprising
The crosslinked surface layer is an electrostatic latent image carrier further containing an oxazole compound represented by the following general formula (2) or the following general formula (3).

(In general formula (1), Xa represents a radical polymerizable functional group, R represents a hydrogen atom, a halogen atom, a carboxyl group or an alkyl group which may be substituted by a substituent, and Y ₁ is substituted by a substituent. A divalent alkylene oxide group which may be substituted, Y ₂ represents a single bond, an ether bond or an ester bond, and m is 1 or 2.)

(In General Formula (2), Ra and Rb each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and Zx represents a divalent vinylene group or an aromatic hydrocarbon having 6 to 14 carbon atoms. Group or a 2,5-thiophenediyl group.)

(In the general formula (3), Ar _x and Ar _y each independently represent a monovalent radical of an aromatic hydrocarbon having 6 to 14 carbon atoms, Zy is aromatic hydrocarbon having 6 to 14 carbon atoms Represents a divalent group, and Rc and Rd each independently represent a hydrogen atom or a methyl group.)   2. The electrostatic latent image carrier according to claim 1, wherein the content of the oxazole compound is 0.5 to 10% by mass with respect to the mass of the radical polymerizable compound having the charge transporting structure.   The electrostatic latent image carrier according to claim 1, wherein the radical polymerizable reactive group of the radical polymerizable compound having a charge transporting structure is an acryloyloxy group.   The value of the ratio of the content of the monofunctional radical polymerizable compound and the trifunctional or higher functional radical polymerizable compound not having the charge transporting structure is 1/9 to 7/3. The electrostatic latent image carrier according to any one of claims 1 to 3.   The electrostatic latent image carrier according to any one of claims 1 to 4, wherein the radical polymerizable compound having a charge transporting structure is monofunctional.   The electrostatic latent image carrier according to claim 1, wherein the radical polymerizable compound having a charge transporting structure has a molecular weight ratio of 300 or more to the number of radical polymerizable functional groups.   The trifunctional or higher functional radical polymerizable compound having no charge transporting structure includes a monomer having a molecular weight ratio of 300 or higher to the number of radical polymerizable functional groups, according to any one of claims 1 to 6. An electrostatic latent image carrier.   The electrostatic latent image carrier according to claim 1, wherein the crosslinked surface layer includes organic filler fine particles or inorganic filler fine particles. The electrostatic latent image carrier according to any one of claims 1 to 8,
Charging means for charging the electrostatic latent image carrier;
Exposure means for exposing the charged electrostatic latent image carrier to form an electrostatic latent image; and
Developing means for developing the electrostatic latent image with toner to form a toner image;
An image forming apparatus having transfer means for transferring the toner image to a recording medium;   A process cartridge that integrally supports the electrostatic latent image carrier according to any one of claims 1 to 8 and at least one of a charging unit, a developing unit, and a cleaning unit.

Images