JP4796519B2 - Image carrier, image forming apparatus using the same, process cartridge, and image forming method - Google Patents

Description

  The present invention relates to an image carrier that has high wear resistance and can maintain high-quality image formation over a long period of time while maintaining stable electrical characteristics, and an image forming apparatus using the image carrier. The present invention relates to a process cartridge for an image forming apparatus and an image forming method.

  In recent years, organic photoreceptors (OPCs) have various advantages in addition to good performance, so that they are widely used in copying machines, facsimiles, laser printers, and their combined machines in place of inorganic photoreceptors. The reason why the organic photoreceptor is used is, for example, (1) optical characteristics such as light absorption wavelength range and absorption amount, (2) electrical characteristics such as high sensitivity and stable charging characteristics, ( 3) Wide selection range of materials, (4) Ease of manufacturing, (5) Low cost, (6) Non-toxicity, etc.

  On the other hand, the diameter of the photoconductor has recently been reduced due to the downsizing of the image forming apparatus, and the high speed of the machine and the maintenance-free movement have been added to increase the durability of the photoconductor. From this point of view, organophotoreceptors are generally soft because the surface layer is mainly composed of low-molecular charge transport materials and inert polymers, and when used repeatedly in electrophotographic processes, they are mechanically driven by development systems and cleaning systems. It has the disadvantage of being easily worn by a typical load. In addition, for the purpose of improving the cleaning property corresponding to the reduction in the particle size of the toner particles accompanying the demand for higher image quality, the rubber hardness of the cleaning blade and the contact pressure must be increased. It is a factor that promotes body wear.

Such wear of the photoreceptor deteriorates electrical characteristics such as sensitivity deterioration and chargeability, and causes abnormal images such as image density reduction and background stains. Further, scratches where wear is locally generated cause streak-like stain images due to poor cleaning. Under the present circumstances, the wear and scratches of the photoconductor are ruled and replaced.
Therefore, in order to increase the durability of the organic photoreceptor, it is indispensable to reduce the above-mentioned wear amount, and is the most pressing issue in this field.

  Techniques for improving the abrasion resistance of the photosensitive layer include (1) using a curable binder for the surface layer (for example, see Patent Document 1), and (2) using a polymeric charge transport material (for example, , Patent Document 2), (3) An inorganic filler dispersed in a surface layer (for example, see Patent Document 3) has been proposed.

Among the above techniques, those using the curable binder (1) have poor compatibility with the charge transport material, and the residual potential increases due to impurities such as polymerization initiators and unreacted residues, resulting in a decrease in image density. Tends to occur.
In addition, the polymer charge transport material (2) and the inorganic filler (3) dispersed can be improved to some extent, but are required for organic photoreceptors. The durability has not been fully satisfied. Further, in the case where the inorganic filler (3) is dispersed, the residual potential increases due to traps present on the surface of the inorganic filler, and the image density tends to decrease.
Therefore, the technologies (1), (2), and (3) above sufficiently satisfy the overall durability including the electrical durability and mechanical durability required for the organic photoreceptor. It has not been done.

Further, a photoreceptor containing a polyfunctional curable acrylate monomer in order to improve wear resistance and scratch resistance is also known in relation to the technique (1) (for example, see Patent Document 4).
However, in this photoreceptor, although there is a description that the polyfunctional curable acrylate monomer is contained in the protective layer provided on the photosensitive layer, the protective layer may contain a charge transport material. However, when the surface layer contains a low-molecular charge transporting substance, there is a problem of compatibility with the cured product. In some cases, the molecular charge transport material is precipitated and cracks are generated, and the mechanical strength is also lowered. There is also a statement that a polycarbonate resin is contained for improving compatibility, but the content of the curable acrylic monomer is reduced, and as a result, sufficient wear resistance cannot be achieved. In addition, for photoreceptors that do not contain a charge transport material in the surface layer, there is a description that the surface layer is made a thin film to reduce the potential of the exposed area. At present, the partial potential has not been maintained sufficiently.

As an alternative technique for improving the abrasion resistance of photosensitive layers, a charge transport formed using a coating solution comprising a monomer having a carbon-carbon double bond, a charge transport material having a carbon-carbon double bond, and a binder resin. It is known to provide a layer (see, for example, Patent Document 5).
This binder resin in this technology includes those having a carbon-carbon double bond and having reactivity to the charge transporting substance, and those having no double bond and not having reactivity. . This photoreceptor is noticed from the viewpoint of achieving both wear resistance and good electrical characteristics. However, when a non-reactive binder resin is used, the compatibility between the binder resin and the cured product produced by the reaction between the monomer and the charge transport material is poor, and surface unevenness is caused during phase separation to crosslinking. Tended to cause poor cleaning.
In the above case, the binder resin hinders the curing of the monomer, and what is specifically described as the monomer used in the photoconductor is a bifunctional one. In this bifunctional monomer, the number of functional groups However, a sufficient crosslink density was not obtained, and it was not yet satisfactory in terms of wear resistance. Further, even when a reactive binder is used, it is difficult to achieve both the binding amount and the crosslinking density of the charge transport material due to the low number of functional groups contained in the monomer and the binder resin, and the electrical characteristics and The abrasion resistance was not sufficient.

  A photosensitive layer containing a compound obtained by curing a hole transporting compound having two or more chain polymerizable functional groups in the same molecule is also known (see, for example, Patent Document 6). However, in this photosensitive layer, the bulky hole transporting compound has two or more chain-polymerizable functional groups, so that distortion occurs in the cured product and the internal stress increases, resulting in rough surface layers and cracks over time. May occur easily and does not have sufficient durability.

Furthermore, as a method for solving the problems with respect to wear resistance, electrical characteristics, surface properties, and cracks, a cross-linkable charge transport layer of 1 to 10 μm is provided on the charge transport layer, and the cross-linkable charge transport layer is charged. There has been proposed a photoreceptor formed by curing a tri- or higher functional radical polymerizable monomer having no transporting structure and a radical polymerizable compound having a monofunctional charge transporting structure (see, for example, Patent Document 7). ).
In this proposal, by providing a specific cross-linked charge transport layer, it is possible to greatly improve the durability of the photoreceptor, and it has excellent wear resistance compared to the above Patent Documents 1-6. It has become possible to obtain a photoreceptor that can maintain stable electrical characteristics.

However, in recent years, as the processing speed of information processing terminals has increased, technology for handling a large amount of information in a short time has progressed day by day. There is a growing demand for greater durability that can withstand the use of paper. The photoconductor disclosed in Patent Document 7 also has a problem in that abnormal images are generated due to deterioration of electrical characteristics, because the performance when the paper is repeatedly passed over a long period of 1 million sheets or more is not always sufficient.
In other words, the above-mentioned main abnormal image at the time of repetitive paper passing is a residual image due to the reverse polarity charge when the toner image is transferred to the transfer member. In the image forming apparatus, abnormal images are noticeably generated.

As a method for solving an abnormal image in the direct transfer method, an electrophotographic photosensitive member in which a charge blocking layer, a moire preventing layer, a photosensitive layer, and a protective layer are sequentially laminated on a conductive support has been proposed (for example, , See Patent Document 8).
That is, the protective layer of the electrophotographic photosensitive member cures a radically polymerizable compound having a trifunctional or higher functional group having no charge transporting structure and a radically polymerizable compound having a monofunctional charge transporting structure, as in Patent Document 7 described above. This is a photoreceptor formed. However, although it was possible to obtain superior durability compared to Patent Document 7, the occurrence of the afterimage was confirmed in the repeated use of 1 million sheets or more, and mechanical durability and stability were confirmed. However, it is not yet sufficient as an image carrier for maintaining good electrical characteristics and realizing good image formation over a long period of time, and further performance improvement is demanded.

JP-A-56-48637 JP-A 64-1728 JP-A-4-281461 Japanese Patent No. 3262488 Japanese Patent No. 3194392 JP 2000-66425 A JP 2004-302451 A Japanese Patent Laid-Open No. 2006-227496

  The present invention has been made in view of the above prior art, and an object of the present invention is for an image forming apparatus having high wear resistance and capable of forming a high-quality image over a long period of time with stable electrical characteristics. An image carrier is provided, and an image forming apparatus, a process cartridge for the image forming apparatus, and an image forming method using the long-life and high-performance image carrier are provided.

  As a result of intensive studies, the present inventors have found that the above problems can be solved by the inventions described in the following (1) to (15), and have reached the present invention. Hereinafter, the present invention will be specifically described.

(1): The above problem is in an image carrier having a charge generation layer, a charge transport layer, and a surface protective layer on a conductive support.
The charge transport layer contains a compound represented by the following general formula (I), and the surface protective layer has at least a trifunctional or higher-functional radical polymerizable compound having no charge transport structure, and 1 having a charge transport structure. The ratio (t ₂ / t ₁ ) of the film thickness (t ₂ ) of the surface protective layer to the film thickness (t ₁ ) of the charge transport layer, comprising a cross-linked curable resin that is a reaction product with a functional radical polymerizable compound Is solved by an image carrier characterized by having a value of 0.7 to 1.3.

[In the general formula (I), R ₇ , R ₈ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ may be the same or different and each represents a hydrogen atom, a lower alkyl group, an alkoxy group, A phenoxy group, a halogen atom or an optionally substituted aryl group is shown, and p ¹ and p ^{2 each} represents 0 or 1. Z is a hydrogen atom, a lower alkyl group, an alkoxy group, a phenoxy group, a halogen atom, an aryl group which may have a substituent, or the following general formulas (Za), (Zb), (Zc):

(Wherein R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ and p ¹ and p ² are the same as those shown in the general formula (I), and R ₁₄ and R ₁₅ are the same or different. Or a hydrogen atom, a lower alkyl group, an alkoxy group, a phenoxy group, a halogen atom or an aryl group which may be substituted, and p ³ represents 0 or 1. ]

(2): The image carrier according to (1) above, wherein the surface protective layer has a thickness (t ₂ ) of 10 μm to 20 μm.

By setting the film thickness (t ₁ ) of the charge transport layer within the above range and the film thickness ratio (t ₂ / t ₁ ) of 0.7 to 1.3, excellent wear resistance and electrical stability can be obtained. A balanced image can be formed, and a high-quality image can be formed even when paper is repeatedly passed over a long period of 1 million sheets or more.

  (3): In the image carrier according to the above (1) or (2), the charge transport layer contains a compound represented by the following general formula (II) in addition to the compound represented by the general formula (I). It is characterized by containing.

(In the general formula (II), Ar ₁ and Ar ₂ represent a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic group, and R ₁ , R ₂ and R ₃ are hydrogen atoms, substituted or unsubstituted. Represents an alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, R ₂ and R ₃ may be bonded to each other to form a ring, Ar ₃ represents a substituted or unsubstituted arylene group, and n represents 0 or 1.)

A charge transport layer containing the compound represented by the general formula (I) and the general formula (II), and the ratio (t ₂ / r) between the film thickness (t ₁ ) and the film thickness (t ₂ ) of the surface protective layer By setting t ₁ ) to 0.7 to 1.3, even when paper is repeatedly passed over a long period of 1 million sheets or more, electrical deterioration is further suppressed, and in particular, an afterimage caused by a reverse polarity charge during transfer is suppressed. Occurrence is also avoided and high quality images can be formed over a long period of time.

  (4): The image carrier according to any one of (1) to (3) above, wherein the charge generation layer contains a titanyl phthalocyanine pigment.

  If the titanyl phthalocyanine pigment is used as a charge generation material, the sensitivity increases and the injection efficiency with the charge transport layer improves, reducing the number of reverse-polarity trap sites. It is also preferable in avoiding image generation.

  (5): The image carrier according to any one of (1) to (3) above, wherein the charge generation layer contains a titanyl phthalocyanine pigment and a disazo pigment.

  When the mixture of the titanyl phthalocyanine pigment and the disazo pigment is used as a charge generation material, it exhibits excellent characteristics with no occurrence of abnormal images even after repeated use over a longer period.

  (6): In the image carrier according to any one of (1) to (5), the functional group of the monofunctional radically polymerizable compound having the charge transporting structure is an acryloyloxy group or a methacryloyloxy group. It is characterized by being.

  Based on the above, a surface protective layer is formed which is easily crosslinked by heating or application of light energy to form a cured resin, which retains high durability even at high speed and repeated use, and provides high image quality.

  (7): In the image carrier according to any one of (1) to (6) above, the monofunctional radically polymerizable compound having the charge transporting structure has a triarylamine structure as a charge transporting structure. It is characterized by being.

  If a radically polymerizable compound containing a triarylamine structure is used as the charge transport structure, a surface protective layer having a high charge transport effect can be formed.

  (8): In the image carrier according to any one of (1) to (7), the monofunctional radically polymerizable compound having the triarylamine structure is represented by the following general formula (1) or (2): It is characterized by being one or more radically polymerizable compounds shown.

[In the formulas (1) and (2), R ₁ may have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Aryl group, cyano group, nitro group, alkoxy group, —COOR ₇ (R ₇ has a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. May be an aryl group), a carbonyl halide group or CONR ₈ R ₉ (R ₈ and R ₉ are a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl which may have a substituent) Represents an aryl group which may have a group or a substituent, and may be the same or different from each other), Ar ₁ and Ar ₂ represent a substituted or unsubstituted arylene group, and May be different. Ar ₃ and Ar ₄ represent a substituted or unsubstituted aryl group, and may be the same or different. X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group. Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group, or an alkyleneoxycarbonyl group. m and n represent an integer of 0 to 3. ]

  (9): In the image carrier described in (7) or (8) above, the monofunctional radically polymerizable compound having the triarylamine structure is one or more types of radical polymerization represented by the following general formula (3): It is a characteristic compound.

  [In the formula (3), o, p and q are each an integer of 0 or 1; Ra represents a hydrogen atom or a methyl group; Rb and Rc represent an alkyl group having 1 to 6 carbon atoms; May be. s and t represent an integer of 0 to 3. Za represents a single bond, a methylene group, an ethylene group, or a divalent group represented by the following formulas (4), (5), and (6). ]

  According to the above (7) and (8), the wear resistance and the electrical characteristics are well balanced and there is no decrease in sensitivity or increase in the residual potential even during long-term repeated use, and the electrical characteristics are maintained well.

  (10): The image bearing member according to any one of (1) to (9) above, wherein the curing means of the cross-linked curable resin forming the surface protective layer is by heating or light energy irradiation. To do.

  If a curing means by heating or light energy irradiation is used, a trifunctional or higher functional radical polymerizable compound having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure can be easily cross-linked and reacted. A cross-linked curable resin can be formed as a product. Such a cross-linked curable resin maintains high durability even at high speed and repeated use, and high image quality is obtained.

  (11): The above problem is solved by an image forming apparatus comprising at least the image carrier according to any one of claims 1 to 10, and a charging unit, an exposure unit, a developing unit, and a transfer unit. .

  (12) In the image forming apparatus described in (11) above, the linear velocity of the image carrier is 500 mm / s or more.

  If the linear velocity is set, the output speed of the image forming apparatus can be increased and a large amount of information can be handled in a short time.

  (13): The above problem is at least one selected from the group consisting of the image bearing member according to any one of (1) to (10), a charging unit, a developing unit, a transfer unit, a cleaning unit, and a neutralizing unit. The problem is solved by a process cartridge characterized in that it comprises means and is configured to be detachable from the main body of the image forming apparatus.

  (14) The above problem is solved by an image forming apparatus having the process cartridge described in (13) mounted thereon.

(15): The above problem is an image forming method in which at least charging, exposure, development, and transfer are repeated using the image forming apparatus according to any one of (11), (12), and (14),
The image carrier after the image carrier is operated at a linear speed of 500 mm / s or more, the toner image developed on the image carrier is directly transferred to the transfer body, and the toner image is transferred to the transfer body. The image forming method is characterized in that an image is formed such that the surface potential polarity is opposite to that at the time of charging.

According to the image carrier of the present invention, a surface protective layer made of a cured resin having high wear resistance and stable electrical characteristics is provided, and the general formula (I) or (I) and (II) By setting the ratio (t ₂ / t ₁ ) between the film thickness (t ₁ ) of the charge transport layer containing the compound shown and the film thickness (t ₂ ) of the surface protective layer to 0.7 to 1.3, There is no electrical degradation even when paper is repeatedly passed over a long period of 1 million sheets or more, and the generation of afterimages due to reverse polarity charges during transfer is suppressed, and abnormal images are not generated for a long time. High quality image formation can be realized.
According to the image forming apparatus of the present invention, since the image bearing member having excellent wear resistance and electrostatic characteristics is provided, it is highly durable against abrasion even when repeatedly passing over 1 million sheets. Therefore, it is possible to output a high-quality image in a stable state without occurrence of abnormal images due to reverse polarity charges during transfer. Therefore, it can be widely applied to electrophotographic application fields (for example, electrophotographic copying machines, laser beam printers, CRT printers, LED printers, liquid crystal printers, laser plate making, etc.).
According to the process cartridge of the present invention, each process means and the image carrier are integrated, and the relative positional accuracy is high, so that the image quality can be improved and repeated over a long period of 1 million sheets or more. A high-quality image can be formed even on paper or in reverse polarity during transfer, and the image carrier and other process means can be easily replaced in a short time.
According to the image forming apparatus equipped with the process cartridge of the present invention, the replacement can be easily performed in a short time, so that the maintainability is improved and the cost is reduced.
According to the image forming method of the present invention, since the image carrier is provided, it is possible to perform stable image formation over a long period of time even at a high speed and repeated sheet passing of 1 million sheets or more.

Hereinafter, the present invention will be described in detail.
As described above, the image carrier in the present invention is an image carrier having a charge generation layer, a charge transport layer, and a surface protective layer on a conductive support.
The charge transport layer contains a compound represented by the following general formula (I), and the surface protective layer has at least a trifunctional or higher-functional radical polymerizable compound having no charge transport structure, and 1 having a charge transport structure. The ratio (t ₂ / t ₁ ) of the film thickness (t ₂ ) of the surface protective layer to the film thickness (t ₁ ) of the charge transport layer, comprising a cross-linked curable resin that is a reaction product with a functional radical polymerizable compound Is 0.7 to 1.3.

[In the general formula (I), R ₇ , R ₈ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ may be the same or different and each represents a hydrogen atom, a lower alkyl group, an alkoxy group, A phenoxy group, a halogen atom or an optionally substituted aryl group is shown, and p ¹ and p ^{2 each} represents 0 or 1. Z is a hydrogen atom, a lower alkyl group, an alkoxy group, a phenoxy group, a halogen atom, an aryl group which may have a substituent, or the following general formulas (Za), (Zb), (Zc):

(Wherein R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ and p ¹ and p ² are the same as those shown in the general formula (I), and R ₁₄ and R ₁₅ are the same or different. Or a hydrogen atom, a lower alkyl group, an alkoxy group, a phenoxy group, a halogen atom or an aryl group which may be substituted, and p ³ represents 0 or 1. ]

As described above, the image carrier of the present invention is a reaction product of at least a trifunctional or higher functional radical polymerizable compound having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure. A surface protective layer made of a cross-linked curable resin having a developed three-dimensional network structure is provided, whereby long-term wear resistance is improved and stable electrical characteristics are maintained.
Further, as a result of the study by the present inventors, the charge transporting layer contains the compound represented by the general formula (I), and the film thickness (t ₂ ) of the surface protective layer with respect to the film thickness (t ₁ ) of the charge transporting layer. The ratio (t ₂ / t ₁ ) of the film thickness ratio of the surface protective layer to the charge transport layer is 0.7 to 1.3. It has become possible to avoid the occurrence of electrical deterioration, in particular, the occurrence of abnormal images due to reverse polarity charges during transfer (a phenomenon in which afterimages are caused by reverse polarity charges).

  Further, by using a titanyl phthalocyanine pigment or a mixture of a titanyl phthalocyanine pigment and a disazo pigment as a charge generation material used for the charge generation layer, it has become possible to avoid an abnormal image particularly when a paper is repeatedly passed for a long time.

Although the details of the effects of the present invention are not clear, by containing a specific compound represented by the general formula (I) in the charge transport layer, charges of reverse polarity at the time of transfer are trapped in the charge transport layer. The ratio (t ₂ / t ₁ ) between the film thickness (t ₁ ) of the charge transport layer and the film thickness (t ₂ ) of the surface protective layer is assumed to be in the specific range. Thus, it is possible to suppress electrical deterioration of each layer to a minimum, and to avoid abnormal images. In particular, when a titanyl phthalocyanine pigment or a mixture of a titanyl phthalocyanine pigment and a disazo pigment is used as a charge generation material used in the charge generation layer, it remains as a trap when a reverse polarity charge during transfer is injected into the charge generation layer. It is assumed that it became difficult. The present invention will be described in detail below.

First, the surface protective layer (hereinafter sometimes abbreviated as “protective layer”) provided on the image carrier of the present invention will be described.
The image carrier of the present invention reduces the influence of wear caused by repeated use of a photoconductor having a charge generation layer and a charge transport layer on a conductive support and is electrically stable over time. A protective layer is provided on the charge transport layer for the purpose of enhancing the properties. As described above, the protective layer may be expressed as at least a trifunctional or higher functional radical polymerizable compound having no charge transport structure (hereinafter referred to as “a trifunctional or higher functional radical polymerizable monomer having no charge transport structure”). )) And a monofunctional radically polymerizable compound having a charge transporting structure. Then, the ratio (t ₂ / t ₁ ) of the thickness (t ₂ ) of the surface protective layer to the thickness (t ₁ ) of the charge transport layer is adjusted to 0.7 to 1.3.

The main purpose of this protective layer is to increase the abrasion resistance of the photoreceptor, but this makes it possible to suppress an increase in electric field strength due to repeated use, and is effective in suppressing scumming. In addition, there is little increase in residual potential, high scratch resistance on the surface of the photoreceptor, and filming and the like are less likely to occur, so it has the effect of reducing the occurrence of image defects and is effective in realizing high durability. Useful.
In other words, scratches formed on the surface of the photoreceptor and foreign matter (toner, toner external additive, carrier, paper powder, etc.) adhering to the surface reduce the cleaning performance of the photoreceptor and significantly reduce the image quality stability. . Therefore, in order to achieve high durability of the photoconductor, it is important not only to increase the wear resistance, but also to minimize the effects of scratches and filming on the surface of the photoconductor. It is preferable to form a highly elastic and smooth surface layer.

  The protective layer provided on the image carrier of the present invention is obtained by reacting and curing a tri- or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. It is formed by. Therefore, since it has a crosslinked structure, a three-dimensional network structure is developed, a surface layer having a very high crosslinking density and a high hardness and high elasticity is obtained, and it is uniform and smooth, and has high wear resistance and scratch resistance. Achieved.

  Thus, it is important to increase the cross-linking density of the surface layer, that is, the number of cross-linking bonds per unit volume. However, when a large number of bonds are instantaneously formed in the curing reaction, internal stress due to volume shrinkage occurs. Since this internal stress increases as the thickness of the protective layer increases, if the entire protective layer is cured, cracks and film peeling tend to occur. Even if this phenomenon does not appear initially, it is repeatedly used in the electrophotographic process, and may easily occur over time due to the effects of charging, development, transfer, cleaning hazards, and thermal fluctuations.

Methods for solving this problem include (1) introducing a polymer component into the protective layer and the crosslinked structure, (2) using a large amount of monofunctional and bifunctional radically polymerizable monomers, and (3) flexible groups. Although the directionality which softens a protective layer, such as using the polyfunctional monomer which has is mentioned, the crosslinking density of a protective layer becomes thin in any case, and remarkable abrasion resistance is not achieved.
On the other hand, the image carrier (photoreceptor) of the present invention does not cause the above-described cracks or film peeling by providing a protective layer having a high crosslinking density with a developed three-dimensional network structure on the charge transport layer. And very high wear resistance is achieved.

In addition, in the formation of the protective layer of the present invention, in addition to a trifunctional or higher functional radical polymerizable monomer, a radical polymerizable compound having a monofunctional charge transporting structure is contained, which is a trifunctional or higher functional radical. It is incorporated into the cross-linking bond when the polymerizable monomer is cured.
On the other hand, when a low molecular charge transport material having no functional group is contained in the protective layer, the low compatibility of the low molecular charge transport material and white turbidity occur due to its low compatibility. Also decreases. On the other hand, when a bifunctional or higher-functional charge transporting compound is used as the main component, the crosslink structure is fixed by a plurality of bonds and the crosslink density is further increased. Becomes very large, the internal stress of the protective layer is increased, and the above-mentioned cracks are generated.

Furthermore, the image carrier of the present invention has good electrical characteristics, and is therefore excellent in repeated stability, realizing high durability and high stability. This is because a radically polymerizable compound having a monofunctional charge transporting structure is used as a constituent material of the protective layer, and is immobilized in a pendant shape between crosslinks.
In the case of using a charge transport material having no functional group, precipitation and clouding phenomenon occur, and the electrical characteristics are remarkably deteriorated in repeated use such as a decrease in sensitivity and an increase in residual potential. When a bifunctional or higher-functional charge transporting compound is used as the main component, it is fixed in the crosslinked structure with a plurality of bonds, so the intermediate structure (cation radical) during charge transport cannot be kept stable, Sensitivity drop and residual potential increase are likely to occur due to trapping, and the deterioration of these electrical characteristics appears as an image of reduced image density, thinned characters, and the like.

  As described above, since the surface protective layer of the present invention has excellent wear resistance and electrical stability, it can obtain good characteristics even when formed in a wide range of film thickness. However, in order to obtain long-term stability, it is necessary to consider the balance with the thickness of the charge transport layer, so the thickness is 8 to 24 μm, more preferably 10 to 20 μm. Is desirable.

As described later, the surface protective layer provided in the image carrier in the present invention includes at least a trifunctional or higher functional radical polymerizable compound having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure. Can be formed on the charge transport layer using a coating solution (surface protective layer coating solution) containing the above in a solvent and subjected to a curing reaction by heating or irradiation with light energy.
Below, the constituent material of the surface protective layer coating liquid of this invention is demonstrated.

  Examples of the trifunctional or higher functional radical polymerizable compound having no charge transporting structure (trifunctional or higher functional radical polymerizable monomer having no charge transporting structure) used in the present invention include triarylamine, hydrazone, pyrazoline, It does not have a hole transporting structure such as carbazole, or an electron transporting structure such as condensed polycyclic quinone, diphenoquinone, an electron-withdrawing aromatic ring having a cyano group or a nitro group, and 3 radical polymerizable functional groups. It refers to a monomer having more than one.

  The radical polymerizable functional group may be any group that has a carbon-carbon double bond and is capable of radical polymerization. Examples of these radical polymerizable functional groups include 1-substituted ethylene functional groups and 1,1-substituted ethylene functional groups shown below.

  (A) As 1-substituted ethylene functional group, the functional group represented by following General formula (7) is mentioned, for example.

[In the formula (7), X ₁ represents an arylene group which may have a substituent, an alkenylene group which may have a substituent, a —CO— group, a —COO— group, a —CON ( R ₁₀₎ - group (R ₁₀ represents hydrogen, an alkyl group, an aralkyl group, a), or -S- group or an aryl group.. ]

Specific examples of the arylene group which may have a substituent include a phenylene group and a naphthylene group. Specific examples of the alkyl group in R ₁₀ include a methyl group and an ethyl group as an aralkyl group. Examples of the aryl group include a benzyl group, a naphthylmethyl group, and a phenethyl group. Examples of the aryl group include a phenyl group and a naphthyl group.

  Specific examples of the functional group represented by the general formula (7) include vinyl group, styryl group, 2-methyl-1,3-butadienyl group, vinylcarbonyl group, acryloyloxy group, acryloylamino group, vinylthioether. Groups and the like.

  Examples of the (b) 1,1-substituted ethylene functional group include a functional group represented by the following general formula (8).

[In the formula (8), Y represents an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, or a halogen atom. , A cyano group, a nitro group, an alkoxy group, a —COOR ₁₁ group (R ₁₁ has a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, and a substituent. Or -CONR ₁₂ R ₁₃ group (R ₁₂ and R ₁₃ may be a hydrogen atom, an alkyl group which may have a substituent, or a substituent. Represents a good aralkyl group or an aryl group which may have a substituent, and may be the same or different from each other. X ₂ represents the same substituent, single bond, and alkylene group as X _{1 in the} general formula (7). However, at least one of Y and X ₂ is an oxycarbonyl group, a cyano group, an alkenylene group, or an aromatic ring. ]

Phenyl group Examples of the aryl group which may have a substituent in the Y, naphthyl group and the alkoxy group, a methoxy group or an ethoxy group, and also, the substituents on R ₁₁ Specific examples of the alkyl group that may have a methyl group, an ethyl group, etc., and the aralkyl group that may have a substituent, a benzyl, phenethyl group, etc. may have a substituent. Examples of the aryl group include a phenyl group and a naphthyl group, and specific examples of the alkyl group which may have a substituent in R ₁₂ and R ₁₃ include a methyl group, an ethyl group, and the like. Examples of the aralkyl group which may be present include a benzyl group, a naphthylmethyl group and a phenethyl group, and examples of the aryl group which may have a substituent include a phenyl group and a naphthyl group. That.

  Specific examples of the 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.

In addition, examples of the substituent further substituted with the substituent for X ₁ , X ₂ , and Y include, for example, a halogen atom, a nitro group, a cyano group, a methyl group, an alkyl group such as an ethyl group, a methoxy group, 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.

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

Specific examples of the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure include the following, but are not limited to these compounds.
That is, examples of the radical polymerizable monomer used in the present invention include trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, trimethylolpropane alkylene-modified triacrylate, trimethylolpropane ethyleneoxy-modified (hereinafter referred to as EO modification). ) Triacrylate, trimethylolpropane propyleneoxy modified (hereinafter PO modified) triacrylate, trimethylolpropane caprolactone modified triacrylate, trimethylolpropane alkylene modified trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol triacrylate Glycerol epichlorohydrin modified (hereinafter ECH modified) Acrylate, glycerol EO modified triacrylate, glycerol PO modified triacrylate, tris (acryloxyethyl) isocyanurate, dipentaerythritol hexaacrylate (DPHA), dipentaerythritol caprolactone modified hexaacrylate, dipentaerythritol hydroxypentaacrylate, alkylated di Pentaerythritol pentaacrylate, alkylated dipentaerythritol tetraacrylate, alkylated dipentaerythritol triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, phosphoric acid EO-modified triacrylate, 2, 2, 5, 5 , -Tetrahydroxymethylcyclopentanone tetraacrylate And the like, which can be used in combination singly or two or more kinds.

  The trifunctional or higher functional radical polymerizable monomer having no charge transporting structure used in the present invention is a ratio of molecular weight to the number of functional groups in the monomer in order to form a dense crosslink in the protective layer ( The molecular weight / number of functional groups) is preferably 250 or less. Further, when this ratio is larger than 250, the protective layer is soft and the wear resistance tends to be somewhat lowered. Therefore, among the monomers exemplified above, among monomers having a modifying group such as EO, PO, caprolactone, etc. It is not preferable to use a compound having an extremely long modifying group alone. Further, the proportion of the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure used in the protective layer is 20 to 80% by weight, preferably 30 to 70% by weight, based on the total amount of the protective layer. When the monomer component is less than 20% by weight, the three-dimensional cross-linking density of the protective layer is small, and it is difficult to achieve a dramatic improvement in wear resistance as compared with the case of using a conventional thermoplastic binder resin. On the other hand, when it exceeds 80% by weight, the content of the charge transporting compound is lowered, and the electrical characteristics tend to be deteriorated.

  The monofunctional radically polymerizable compound having a charge transporting structure used in the present invention is, for example, a hole transporting structural part such as triarylamine, hydrazone, pyrazoline, carbazole, or condensed polycyclic quinone, diphenoquinone, A compound having an electron transport structure such as an electron-withdrawing aromatic ring having a cyano group or a nitro group and having a radical polymerizable functional group. The radical polymerizable functional group may be any group as long as it has a carbon-carbon double bond and is capable of radical polymerization. Examples of these radical polymerizable functional groups include 1-substituted ethylene functional groups and 1,1-substituted ethylene functional groups as in the functional groups contained in the above-described trifunctional or higher radical polymerizable monomers having no charge transport structure. Groups and the like.

  As the charge transporting structure, a triarylamine structure has a high charge transporting effect. Furthermore, when a compound represented by the structure of the following general formula (1) or (2) is used, electrical characteristics such as sensitivity and residual potential are favorably maintained.

[In the formulas (1) and (2), R ₁ may have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Aryl group, cyano group, nitro group, alkoxy group, —COOR ₇ (R ₇ has a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. May be an aryl group), a carbonyl halide group or CONR ₈ R ₉ (R ₈ and R ₉ are a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl which may have a substituent) Represents an aryl group which may have a group or a substituent, and may be the same or different from each other), Ar ₁ and Ar ₂ represent a substituted or unsubstituted arylene group, and May be different. Ar ₃ and Ar ₄ represent a substituted or unsubstituted aryl group, and may be the same or different. X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group. Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group, or an alkyleneoxycarbonyl group. m and n represent an integer of 0 to 3. ]

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

Substituted or unsubstituted Ar ₃ and Ar ₄ are aryl groups, and examples of the aryl group include condensed polycyclic hydrocarbon groups, non-fused cyclic hydrocarbon groups, and heterocyclic groups.

  The condensed polycyclic hydrocarbon group preferably has 18 or less carbon atoms forming a ring, for example, a pentanyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptaenyl group, a biphenylenyl group, an as-indacenyl group. , S-indacenyl group, fluorenyl group, acenaphthylenyl group, preadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrenyl group, aceanthrylenyl group, triphenylyl group, pyrenyl group , A chrycenyl group, a naphthacenyl group, and the like.

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

Examples of the heterocyclic group include monovalent groups such as carbazole, dibenzofuran, dibenzothiophene, oxadiazole, and thiadiazole.
The aryl group represented by Ar ₃ or Ar ₄ may have a substituent as shown below, for example.

(1): A halogen atom, a cyano group, a nitro group, etc. are mentioned.
(2): Alkyl groups, preferably C1-C12, especially C1-C8, more preferably C1-C4 linear or branched alkyl groups. These alkyl groups further have a phenyl group substituted with a fluorine atom, a hydroxyl group, a cyano group, a C1-C4 alkoxy group, a phenyl group or a halogen atom, a C1-C4 alkyl group or a C1-C4 alkoxy group. It may be. Specifically, methyl group, ethyl group, n-butyl group, i-propyl group, t-butyl group, s-butyl group, n-propyl group, trifluoromethyl group, 2-hydroxyethyl group, 2-ethoxyethyl Group, 2-cyanoethyl group, 2-methoxyethyl group, benzyl group, 4-chlorobenzyl group, 4-methylbenzyl group, 4-phenylbenzyl group and the like.
(3): include an alkoxy group (-OR ₂₎ it is. R ₂ represents the alkyl group defined in (2). Specifically, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, t-butoxy group, n-butoxy group, s-butoxy group, i-butoxy group, 2-hydroxyethoxy group, benzyloxy group And a trifluoromethoxy group.
(4): An aryloxy group is mentioned. Examples of the aryl group of the aryloxy group include a phenyl group and a naphthyl group. This may contain a C1-C4 alkoxy group, a C1-C4 alkyl group or a halogen atom as a substituent. Specific examples include a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a 4-methoxyphenoxy group, and a 4-methylphenoxy group.
(5): Alkyl mercapto group or aryl mercapto group may be mentioned. Specific examples include a methylthio group, an ethylthio group, a phenylthio group, and a p-methylphenylthio group.
(6): Examples include a group represented by the following general formula (9).

(In Formula (9), R ₃ and R ₄ each independently represent a hydrogen atom, an alkyl group defined in (2) above, or an aryl group. R ₃ and R ₄ may form a ring together. .)
As said aryl group, a phenyl group, a biphenyl group, or a naphthyl group is mentioned, for example, These may contain a C1-C4 alkoxy group, a C1-C4 alkyl group, or a halogen atom as a substituent. Specifically, amino group, diethylamino group, N-methyl-N-phenylamino group, N, N-diphenylamino group, N, N-di (tolyl) amino group, dibenzylamino group, piperidino group, morpholino group And pyrrolidino group.

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

In the general formulas (1) and (2), the substituted or unsubstituted arylene group represented by Ar ₁ or Ar ₂ is a divalent derivative derived from the aryl group represented by Ar ₃ or Ar _4. Groups.

In the general formulas (1) and (2), X (= X ₁ , X ₂ ) is a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, substituted or unsubstituted, as described above. A substituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group is represented.

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

  The substituted or unsubstituted cycloalkylene group is a C5-C7 cyclic alkylene group, and these cyclic alkylene groups have a fluorine atom, a hydroxyl group, a C1-C4 alkyl group, and a C1-C4 alkoxy group. May be. Specific examples include a cyclohexylidene group, a cyclohexylene group, and a 3,3-dimethylcyclohexylidene group.

  The substituted or unsubstituted alkylene ether group represents ethyleneoxy, propyleneoxy, ethylene glycol, propylene glycol, diethylene glycol, tetraethylene glycol, or tripropylene glycol. The alkylene group of the alkylene ether group is a hydroxyl group, a methyl group, or an ethyl group. You may have substituents, such as group.

  Examples of the vinylene group include groups represented by the following general formula (10) or general formula (11).

[Wherein R ₅ represents hydrogen, an alkyl group [the same as the alkyl group defined in the above (2)], an aryl group [the same as the aryl group defined in the above Ar ₃ or Ar ₄ ], and a is 1 Or 2, b represents the integer of 1-3. ]

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

  In addition, the radical polymerizable compound having a monofunctional charge transport structure of the present invention is more preferably a compound having the structure of the following general formula (3).

  [In the formula (3), o, p and q are each an integer of 0 or 1; Ra represents a hydrogen atom or a methyl group; Rb and Rc represent an alkyl group having 1 to 6 carbon atoms; May be. s and t represent an integer of 0 to 3. Za represents a single bond, a methylene group, an ethylene group, or a divalent group represented by the following formulas (4), (5), and (6). ]

  As the compound represented by the general formula (3), compounds having a methyl group or an ethyl group are particularly preferable as substituents for Rb and Rc.

  The monofunctional radically polymerizable compound having a monofunctional charge transport structure represented by the general formulas (1) and (2), particularly (3) used in the present invention, has a carbon-carbon double bond open on both sides. In the polymer formed into a crosslink by polymerization with a radical polymerizable monomer that does not have a terminal structure but is incorporated into a chain polymer and does not have a charge transporting structure, the main chain of the polymer It exists in the bridge chain between the main chain and the main chain. This cross-linked chain was polymerized between one polymer and another intermolecular cross-linked chain between the other polymer, a portion of the main chain folded in one polymer, and a position away from it in the main chain. There are intramolecular cross-linked chains generated by cross-linking with other sites derived from the monomer. Therefore, whether present in the main chain or in the bridging chain, the triarylamine structure suspended from the chain moiety is at least three aryls arranged radially from the nitrogen atom. It has a group, is bulky, but is not directly bonded to the chain part, but is suspended from the chain part via a carbonyl group or the like, and is fixed in a state where it has flexibility in three-dimensional positioning. Therefore, since these triarylamine structures can be arranged spatially adjacent to each other in the polymer, there is little structural distortion in the molecule, and charge transport is achieved when the surface layer of the electrophotographic photoreceptor is used. It is presumed that an intramolecular structure that can avoid the disruption of the pathway can be taken.

  The monofunctional radically polymerizable compound having a charge transporting structure in the present invention can be synthesized, for example, by the method described in Japanese Patent No. 3164426. Specific examples of monofunctional radically polymerizable compounds having a charge transporting structure are as follows. 1-No. Although shown in the structural formula 160, it is not limited to compounds having these structures.

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

  The surface protective layer according to the present invention includes a trifunctional or higher functional radical polymerizable compound having no charge transport structure as described above, a monofunctional radical polymerizable compound having a charge transport structure and a composition as a component. The coating liquid can be applied on the charge transport layer and simultaneously cured by heating or light energy irradiation. When forming this protective layer, in addition to the above components, for the purpose of imparting functions such as viscosity adjustment during coating of the surface layer, stress relaxation of the surface protective layer, low surface free energy and friction coefficient reduction, etc. Such radically polymerizable monomers and radically polymerizable oligomers can be used in combination. In addition, a well-known thing can be utilized as these radically polymerizable monomers and oligomers.

Examples of the radical polymerizable monomer that can be used in combination include the following, but are not limited to these compounds.
That is, examples of the radical polymerizable monomer used in the present invention include trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, HPA-modified trimethylolpropane triacrylate, EO-modified trimethylolpropane triacrylate, and PO-modified. Trimethylolpropane triacrylate, caprolactone modified trimethylolpropane triacrylate, HPA modified trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol triacrylate, ECH modified glycerol triacrylate, EO modified glycerol triacrylate , PO-modified glycerol triacrylate, Lith (acryloxyethyl) isocyanurate, alkyl-modified dipentaerythritol tetraacrylate, alkyl-modified dipentaerythritol triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, EO-modified phosphate triacrylate, 2, 2 , 5,5, -tetrahydroxymethylcyclopentanone tetraacrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, 2-ethylhexyl carbitol acrylate, 3-methoxybutyl acrylate, Benzyl acrylate, cyclohexyl acrylate, isoamyl acrylate, isobutyl acrylate Rate, methoxytriethylene glycol acrylate, phenoxytetraethylene glycol acrylate, cetyl acrylate, isostearyl acrylate, stearyl acrylate, styrene monomer, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,4-butane Diol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, EO-modified bisphenol A diacrylate, EO-modified bisphenol F diacrylate, neopentyl glycol diacrylate An acrylate etc. are mentioned.

  Examples of the functional monomer include those having a fluorine atom substituted such as octafluoropentyl acrylate, 2-perfluorooctylethyl acrylate, 2-perfluorooctylethyl methacrylate, 2-perfluoroisononylethyl acrylate, and radical polymerizable functional groups. A reactive additive having a group can also be used effectively. These functional monomers may be used alone or in combination of two or more. The content of the functional monomer is 0.01 to 30% by weight, preferably 0.05 to 20% by weight, based on the solid content of the coating liquid that forms the crosslinked surface protective layer.

  Examples of the radical polymerizable oligomer include epoxy acrylate, urethane acrylate, and polyester acrylate oligomers. However, when a large amount of monofunctional and bifunctional radically polymerizable monomers and radically polymerizable oligomers are contained, the three-dimensional cross-linking density of the surface protective layer is substantially reduced, resulting in a decrease in wear resistance. For this reason, the content of these monomers and oligomers is limited to 150 parts by weight or less, preferably 100 parts by weight or less, with respect to 100 parts by weight of the total amount of radically polymerizable monomers having no charge transporting structure.

  As described above, the surface layer of the present invention is formed by simultaneously curing at least a trifunctional or higher functional radical polymerizable compound having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure. However, a polymerization initiator may be contained in the surface protective layer coating solution in order to allow the crosslinking reaction to proceed efficiently as required.

Examples of the polymerization initiator include a thermal polymerization initiator, a photopolymerization initiator, and a mixture thereof.
As thermal polymerization initiators, 2,5-dimethylhexane-2,5-dihydroperoxide, dicumyl peroxide, benzoyl peroxide, t-butylcumyl peroxide
Peroxides such as 2,5-dimethyl-2,5-di (peroxybenzoyl) hexyne-3, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, lauroyl peroxide And azo initiators such as azobisisobutylnitrile, azobiscyclohexanecarbonitrile, methyl azobisisobutyrate, azobisisobutylamidine hydrochloride, 4,4′-azobis-4-cyanovaleric acid.

  Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2- Acetophenone-based or ketal-based photopolymerization initiators such as methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, Benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether Benzoin ether photopolymerization initiators such as benzoin isopropyl ether, benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoylphenyl ether, acrylated benzophenone, Benzophenone photopolymerization initiators such as 1,4-benzoylbenzene, thioxanthones such as 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone Examples of other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoic acid. Phenylethoxyphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10 -Phenanthrene, an acridine type compound, a triazine type compound, an imidazole type compound is mentioned.

Moreover, what has a photopolymerization acceleration effect can also be used individually or in combination with the said photoinitiator.
Examples thereof include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, 4,4′-dimethylaminobenzophenone, and the like.
These polymerization initiators may be used alone or in combination of two or more. The content of the polymerization initiator is 0.5 to 40 parts by weight, preferably 1 to 20 parts by weight with respect to 100 parts by weight of the total content having radical polymerizability.

  The surface protective layer of the present invention is obtained by simultaneously curing a trifunctional or higher functional radical polymerizable compound having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure. Filler fine particles can be contained in the protective layer for the purpose of improving the abrasion.

  When filler fine particles (hereinafter sometimes abbreviated as “filler”) are contained, the average primary particle size of the filler is 0.01 to 0.5 μm. From the viewpoint of sex. When the average primary particle size of the filler is less than 0.01 μm, it causes a decrease in dispersibility and the effect of improving the wear resistance is not sufficiently exhibited. When the average primary particle size exceeds 0.5 μm, the filler is contained in the dispersion. There is a possibility that the settling property of the toner is promoted and toner filming may occur. The higher the filler material concentration in the surface layer is, the higher the wear resistance is, and the better. However, if it is too high, the residual potential increases and the writing light transmittance of the surface layer decreases, which may cause side effects. Therefore, it is about 50% by weight or less, preferably about 30% by weight or less, based on the total solid content.

  Furthermore, these fillers can be surface-treated with at least one kind of surface treatment agent, and it is preferable from the viewpoint of filler dispersibility. Decreasing the dispersibility of the filler not only increases the residual potential, but also decreases the transparency of the coating, causes defects in the coating, and decreases the wear resistance. It can develop into a big problem. As the surface treatment agent, a conventionally used surface treatment agent can be used, but a surface treatment agent capable of maintaining the insulating properties of the filler is preferable.

  The surface treatment amount varies depending on the average primary particle size of the filler used, but is preferably 3 to 30% by weight and more preferably 5 to 20% by weight with respect to the filler weight. If the surface treatment amount is less than this, the filler dispersion effect cannot be obtained, and if it is too much, the residual potential is significantly increased. These filler materials may be used alone or in combination of two or more.

  Furthermore, the coating liquid of the present invention can contain additives such as various plasticizers (for the purpose of stress relaxation and adhesion improvement) and leveling agents as necessary. Known additives can be used as these additives, and plasticizers that are used in general resins such as dibutyl phthalate and dioctyl phthalate can be used, and the amount used is the total solid content of the coating liquid. To 20% by weight or less, preferably 10% or less. As leveling agents, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain can be used, and the amount used is based on the total solid content of the coating liquid. 3% by weight or less is appropriate.

  The composition of the surface protective layer coating solution can contain a binder resin as long as the smoothness, electrical characteristics, and durability of the surface of the photoreceptor are not impaired. However, when a polymer material such as a binder resin is contained in the coating liquid, the polymer material produced by the curing reaction of the radical polymerizable composition (radical polymerizable monomer and radical polymerizable compound having a charge transporting structure) Since the compatibility is deteriorated, phase separation occurs and the surface protective layer surface becomes uneven. Therefore, it is preferable not to use a binder resin.

  The surface protective layer of the present invention comprises a coating liquid containing at least a trifunctional or higher functional radical polymerizable compound having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure on the charge transport layer. It is formed by coating and curing. When the radically polymerizable monomer is a liquid, such a coating liquid can be applied by dissolving other components in the liquid, but if necessary, it is diluted with a solvent and applied.

  Solvents used at this time include alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, tetrahydrofuran, dioxane and propyl ether. Ethers such as dichloromethane, halogens such as dichloromethane, dichloroethane, trichloroethane, and chlorobenzene, aromatics such as benzene, toluene, and xylene, and cellosolves such as methyl cellosolve, ethyl cellosolve, and cellosolve acetate. These solvents may be used alone or in combination of two or more. The dilution ratio with the solvent varies depending on the solubility of the composition, the coating method, and the target film thickness, and is arbitrary. The coating can be performed using a dip coating method, spray coating, bead coating, ring coating method or the like.

  In the present invention, after applying the coating liquid, energy is applied from the outside and cured to form a surface protective layer. The external energy used at this time includes heat, light, and radiation. As a method of applying thermal energy, heating is performed from the coating surface side or the support side using a gas such as air, nitrogen, steam, various heat media, infrared rays, or electromagnetic waves. The heating temperature is preferably 100 ° C. or higher and 170 ° C. or lower. If the heating temperature is lower than 100 ° C., the reaction rate is slow and the reaction is not completely completed. When the temperature is higher than 170 ° C., the reaction proceeds non-uniformly and large distortion occurs in the surface protective layer. In order to proceed the curing reaction uniformly, it is also effective to complete the reaction by heating at a relatively low temperature of less than 100 ° C. and then heating to 100 ° C. or more.

On the other hand, as light energy, UV (ultraviolet) irradiation light sources such as high-pressure mercury lamps and metal halide lamps, which mainly have ultraviolet light emission wavelength, can be used, but visible light is matched to the absorption wavelength of radical polymerizable substances and photopolymerization initiators. A light source can also be selected. Irradiation light amount is 50 mW / cm ² or more, preferably 1000 mW / cm ² or less, it takes time for the curing reaction is less than 50 mW / cm ^2. If it is higher than 1000 mW / cm ² , the reaction proceeds non-uniformly and the surface protective layer becomes very rough. Examples of radiation energy include those using electron beams (EB). Among these energies, those using heat and light energy are useful because of easy reaction rate control and simple apparatus.

  Since the film thickness of the surface protective layer of the present invention has excellent wear resistance and electrical stability, good characteristics can be obtained even when formed in a wide range of film thickness. However, in order to obtain long-term stability, it is necessary to consider the balance with the thickness of the charge transport layer. That is, as described above, the film thickness is desirably 8 to 24 μm, more preferably 10 to 20 μm.

Next, the image carrier of the present invention will be described with reference to the drawings.
<About the layer structure of the image carrier>
FIG. 1 is a cross-sectional view showing an example of a layer structure of an image carrier in the present invention.
In FIG. 1A, a charge generation layer (35) having a charge generation function, a charge transport layer (37) having a charge transport function, and a surface protective layer (39) are provided on a conductive support (31). An image bearing member having a laminated structure, that is, a so-called photoconductor. In FIG. 1B, an intermediate layer (undercoat layer) (33) is provided between the conductive support (31) and the charge generation layer (35) in FIG. 1 (A).
The image carrier may be provided with one layer or two or more undercoat layers on the conductive support as necessary. The surface protective layer (39) has a charge transport function.

<About conductive support>
Examples of the conductive support (31) include those having a volume resistance of 10 ¹⁰ Ω · cm or less, for example, metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, oxidation Metal oxide such as indium is deposited or sputtered to form film or cylindrical plastic, paper coated, or aluminum, aluminum alloy, nickel, stainless steel, etc. After conversion, a tube that has been subjected to surface treatment such as cutting, superfinishing, or polishing can be used.
Further, endless nickel belts and endless stainless steel belts disclosed in JP-A-52-36016 can also be used as the conductive support.

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

  Furthermore, it is electrically conductive by a heat-shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon (registered trademark) on a suitable cylindrical substrate. Those provided with a conductive layer can also be used favorably as the conductive support of the present invention.

<About the charge generation layer>
The charge generation layer (35) is a layer mainly composed of a charge generation material having a charge generation function, and a binder resin can be used in combination as necessary.
A known charge generation material can be used for the charge generation layer, and representative examples thereof include phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, azulenium salt pigments, squalic acid methine pigments, and azo compounds having a carbazole skeleton. Pigment, azo pigment having triphenylamine skeleton, azo pigment having diphenylamine skeleton, azo pigment having dibenzothiophene skeleton, azo pigment having fluorenone skeleton, azo pigment having oxadiazole skeleton, azo pigment having bisstilbene skeleton, Azo pigments having a distyryl oxadiazole skeleton, azo pigments having a distyryl carbazole skeleton, perylene pigments, anthraquinone or polycyclic quinone pigments, quinoneimine pigments, diphenylmethane and triphenylmethane pigments, Nzokinon and naphthoquinone pigments, cyanine and azomethine pigments, indigoid pigments, and bisbenzimidazole pigments. These charge generation materials may be used alone or in combination of two or more.

  Furthermore, in the present invention, among the charge generating materials, in particular, it is a kind of metal phthalocyanine pigment, and a titanyl phthalocyanine pigment represented by the following general formula (III) has high sensitivity, and can be used repeatedly for a long time. It is particularly desirable because it exhibits excellent properties.

[In the formula (III), X ₁ , X ₂ , X ₃ and X ₄ each independently represent various halogen atoms, and n, m, l and k each independently represent a number of 0 to 4. ]

  Among the titanyl phthalocyanine pigments, it has a maximum diffraction peak at 27.2 °, and further has main peaks at 9.4 °, 9.6 °, and 24.0 °, and the diffraction at the lowest angle side. Crystalline titanyl phthalocyanine having a peak at 7.3 °, no peak between 7.3 ° peak and 9.4 ° peak, and no peak at 26.3 ° Since the crystal exhibits particularly high sensitivity and exhibits excellent characteristics that do not cause abnormal images particularly during long-term repeated use, it can be used favorably as a charge generating material for the photoreceptor used in the present invention.

  Furthermore, in addition to the above-mentioned titanyl phthalocyanine pigment, by mixing an azo pigment represented by the following general formula (IV), it has been confirmed that it exhibits excellent characteristics without occurrence of abnormal images even in repeated use over a longer period. It can be used satisfactorily as a charge generating material for the photoreceptor used in the present invention.

[In the formula (IV), Cp ₁ and Cp ₂ represent coupler residues. R ₂₀₁ and R ₂₀₂ each represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon chains, an alkoxy group, or a cyano group, and may be the same or different. Cp ₁ and Cp ₂ are represented by the following general formula (V). ]

[In the formula (V), R ₂₀₃ represents a hydrogen atom, an alkyl group or an aryl group, and R ₂₀₄ , R ₂₀₅ , R ₂₀₆ , R ₂₀₇ and R ₂₀₈ are a hydrogen atom, a nitro group, a cyano group or a halogen atom, respectively. , An alkyl group, an alkoxy group, a dialkylamino group, and a hydroxyl group, and Z represents an atomic group necessary for constituting a substituted or unsubstituted aromatic carbocyclic ring or a substituted or unsubstituted aromatic heterocyclic ring. ]

Examples of the alkyl group in R ₂₀₃ include a methyl group and an ethyl group, examples of the aryl group include a phenyl group, and examples of the halogen atom in R ₂₀₄ , R ₂₀₅ , R ₂₀₆ , R ₂₀₇ and R ₂₀₈ include fluorine, chlorine and bromine. , Iodine, etc., examples of the alkyl group include a trifluoromethyl group, a methyl group, and an ethyl group, and examples of the alkoxy group include a methoxy group and an ethoxy group.

  As a binder resin used as necessary for the charge generation layer, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, Examples include polyacrylamide. These binder resins can be used alone or as a mixture of two or more. In addition to the binder resin described above as a binder resin for the charge generation layer, a polymer charge transport material having a charge transport function, such as an arylamine skeleton, benzidine skeleton, hydrazone skeleton, carbazole skeleton, stilbene skeleton, pyrazoline skeleton, Polymer materials (AP) such as polycarbonate, polyester, polyurethane, polyether, polysiloxane, and acrylic resin, polymer materials (PS) having a polysilane skeleton, and the like can be used.

  As specific examples of the former (AP) polymer charge transport material, JP-A-01-001728, JP-A-01-009964, JP-A-01-013061, JP-A-01-019049, JP 01-241559, JP 04-011627, JP 04-175337, JP 04-183719, JP 04-22514, JP 04-230767, JP No. 04-320420, No. 05-232727, No. 05-310904, No. 06-234836, No. 06-234837, No. 06-234838, No. 06-2006 No. 234839, JP-A 06-234840, JP-A 06-234841, JP JP 06-239049, JP 06-236050, JP 06-236051, JP 06-295077, JP 07-056374, JP 08-176293, JP 08- JP 208820, JP 08-21640, JP 08-253568, JP 08-269183, JP 09-062019, JP 09-038883, JP 09-71642. JP-A 09-87376, JP-A 09-104746, JP-A 09-110974, JP-A 09-110976, JP-A 09-157378, JP-A 09-221544, JP 09-227669 A, JP 09-235367 A, JP-A 09-241369, JP-A 09-268226, JP-A 09-272735, JP-A 09-302084, JP-A 09-302085, JP-A 09-328539, etc. Examples include charge transporting polymer materials.

  Specific examples of the latter (PS) include polysilylenes described in, for example, JP-A-63-285552, JP-A-05-19497, JP-A-05-70595, JP-A-10-73944, and the like. Examples are polymers.

The charge generation layer may contain a low molecular charge transport material. Low molecular charge transport materials that can be used in the charge generation layer include hole transport materials and electron transport materials.
Examples of the electron transport material include chloroanil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2, 4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7- Examples thereof include electron-accepting substances such as trinitrodibenzothiophene-5,5-dioxide and diphenoquinone derivatives. These electron transport materials can be used alone or as a mixture of two or more.

Examples of the hole transporting material include the following electron donating materials and are used favorably.
As hole transport materials, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triaryls Other known materials such as methane derivatives, 9-styrylanthracene derivatives, pyrazoline derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, bisstilbene derivatives, enamine derivatives, and the like can be given. These hole transport materials can be used alone or as a mixture of two or more.

  Methods for forming the charge generation layer can be broadly divided into a vacuum thin film preparation method and a casting method from a solution dispersion system. As the former method, a vacuum deposition method, a glow discharge decomposition method, an ion plating method, a sputtering method, a reactive sputtering method, a CVD method, or the like is used, and the above-described inorganic materials and organic materials can be satisfactorily formed.

In addition, in order to provide a charge generation layer by the casting method described later, if necessary, the inorganic or organic charge generation material together with a binder resin, tetrahydrofuran, dioxane, dioxolane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, cyclohexane. Can be formed by dispersing with a ball mill, attritor, sand mill, bead mill, etc. using a solvent such as pentanone, anisole, xylene, methyl ethyl ketone, acetone, ethyl acetate, butyl acetate, etc. . Moreover, leveling agents, such as a dimethyl silicone oil and a methylphenyl silicone oil, can be added as needed. The coating can be performed using a dip coating method, spray coating, bead coating, ring coating method or the like.
The thickness of the charge generation layer provided as described above is suitably about 0.01 to 5 μm, preferably 0.05 to 2 μm.

<About the charge transport layer>
The charge transport layer is a layer having a charge transport function, and is provided between the charge generation layer and the surface protective layer in the present invention. As described above, the charge transport layer is represented by the following general formula (I) as a charge transport material. Contains the indicated compound.

[In the general formula (I), R ₇ , R ₈ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ may be the same or different and each represents a hydrogen atom, a lower alkyl group, an alkoxy group, A phenoxy group, a halogen atom or an optionally substituted aryl group is shown, and p ¹ and p ^{2 each} represents 0 or 1. Z is a hydrogen atom, a lower alkyl group, an alkoxy group, a phenoxy group, a halogen atom, an aryl group which may have a substituent, or the following general formulas (Za), (Zb), (Zc):

(Wherein R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ and p ¹ and p ² are the same as those shown in the general formula (I), and R ₁₄ and R ₁₅ are the same or different. Or a hydrogen atom, a lower alkyl group, an alkoxy group, a phenoxy group, a halogen atom or an aryl group which may be substituted, and p ³ represents 0 or 1. ]

The charge transporting compounds represented by the general formula (I), R ₇ , R ₈ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ , p ¹ and p ² , are shown in Tables 1 to 3 below. Although the combinations shown are mentioned, it is not limited to the compounds of these structures.

  Furthermore, in the present invention, in the charge transport layer, in addition to the compound represented by the general formula (I), a compound represented by the following general formula (II) can be contained. In repetitive use, a more excellent effect can be exhibited and the occurrence of abnormal images can be suppressed.

(In the general formula (II), Ar ₁ and Ar ₂ represent a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic group, and R ₁ , R ₂ and R ₃ are hydrogen atoms, substituted or unsubstituted. Represents an alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, R ₂ and R ₃ may be bonded to each other to form a ring, Ar ₃ represents a substituted or unsubstituted arylene group, and n represents 0 or 1.)

  Specific examples of the compound represented by the general formula (II) are shown in the following table. Specific examples in the case of n = 0 are shown in Tables 4 to 11 below, and specific examples in the case of n = 1 are shown in Table 12 below, but the present invention is not limited thereto.

  In addition to the general formula (I) or the mixture of (I) and (II), the electron transport materials, hole transport materials, and polymer charge transport materials described in the description of the charge generation layer are used. be able to. In particular, the use of a polymer charge transport material is particularly useful because it shows the effect of reducing the solubility of a lower layer (such as a charge transport layer) when forming a surface layer coating.

  A binder resin can be used for the charge transport layer. Examples of such a binder resin include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, and polyester. , Polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N -Thermoplastic or thermosetting resins such as vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin and the like.

  The amount of the charge transport material in the charge transport layer is 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin.

  As the solvent used in the coating solution for the charge transport layer, the same solvent as in the case of the charge generation layer can be used, but a solvent that dissolves the charge transport material and the binder resin well is suitable. These solvents may be used alone or in combination of two or more. In addition, a coating method similar to that for the charge generation layer can be applied to form the charge transport layer.

  Moreover, a plasticizer and a leveling agent can be added to the coating solution for the charge transport layer as necessary. As a plasticizer that can be used in combination with the charge transport layer, those used as plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is 0 with respect to 100 parts by weight of the binder resin. About 30 parts by weight is appropriate.

  Leveling agents that can be used in the charge transport layer coating liquid include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain. In addition, about 0 to 1 part by weight is appropriate for 100 parts by weight of the binder resin.

  As described above, the thickness of the charge transport layer in the present invention is 8 to 24 μm because it is necessary to consider the balance with the thickness of the surface protective layer in order to obtain long-term stability. More preferably, the thickness is 10 to 20 μm.

<About the undercoat layer>
In the image carrier of the present invention, an undercoat layer can be provided as an intermediate layer between the conductive support and the charge generation layer constituting the photosensitive layer.
In general, the undercoat layer is mainly composed of a resin, but it is considered that these resins are formed by coating a charge generation layer, a charge transport layer, and a surface protective layer in order using a coating liquid containing a solvent. It is desirable that the resin has high solvent resistance with respect to general organic solvents.
Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. Further, a metal oxide fine powder pigment exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like may be added to the undercoat layer in order to prevent moire and reduce residual potential.

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

<Addition of antioxidant to each layer>
In the present invention, in order to improve environmental resistance, in order to prevent a decrease in sensitivity and an increase in residual potential, oxidation is performed on each layer such as a surface protective layer, a charge generation layer, a charge transport layer, and an undercoat layer. An inhibitor can be added.
The following are mentioned as antioxidant which can be used for this invention.

(Phenolic compounds)
2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3,5-di-t-butyl-
4-hydroxyphenyl) propionate, 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2′-methylene-bis- (4-ethyl-6-tert-butylphenol), 4 , 4′-thiobis- (3-methyl-6-tert-butylphenol), 4,4′-butylidenebis- (3-methyl-6-tert-butylphenol), 1,1,3-tris- (2-methyl- 4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene -3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3′-bis (4′-hydroxy-3′-t-butylphenyl) butyric Assi Do] Crycol ester, tocopherols and the like.

(Paraphenylenediamines)
N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N'- Di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine and the like.

(Hydroquinones)
2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2-octadecenyl) ) -5-methylhydroquinone and the like.

(Organic sulfur compounds)
Dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, penta Erythritol tetrakis (3-laurylthio-propionate) and the like.

(Organic phosphorus compounds)
Triphenyl phosphite, tris (nonylphenyl) phosphite, tri (dinonylphenyl) phosphite, tris (2-ethylhexyl) phosphite, tridecyl phosphite, tris (tridecyl) phosphite, diphenyl mono (2-ethylhexyl) Phosphite, diphenyl monodecyl phosphite, tris (2,4, di-t-butylphenyl) phosphite, distearyl pentaerythritol diphosphite, bis (2,4, di-t-butylphenyl) pentaerythritol phosphite, 2 , 2-methylenebis (4,6-di-t-butylphenyl) octyl phosphite, tetrakis (2,4-di-t-butylphenyl) 4,4′-biphenylene-diphosphonite, dilauryl hydrogen phosphite, diphenyl Hydrogen phosphite, tetraphenyldipropylene glycol diphosphite, tetraphenyltetra (tridecyl) pentaerythritol tetraphosphite, tetra (tridecyl) -4,4′isopropylidene diphenyldiphosphite, bis (nonylphenyl) pentaerythritol diphos Phyto, hydrogenated bisphenol A, pentaerythritol phosphite polymer, etc.

Each of the above compounds is known as an antioxidant for rubbers, plastics, oils and fats, and can be easily obtained as a commercial product.
It is preferable that the addition amount of the antioxidant in this invention is 0.01 to 10 weight% with respect to the total weight of the layer to add.

<Regarding Image Forming Apparatus and Image Forming Method>
Next, the image forming apparatus and the image forming method of the present invention will be described in detail with reference to the drawings.
The image forming apparatus of the present invention includes the image carrier of the present invention, a charging unit, an exposure unit, a developing unit, and a transfer unit.
The image forming method of the present invention uses an image forming apparatus provided with the image carrier of the present invention, and the image carrier is subjected to charging, image exposure and development processes, and then to an image carrier (transfer paper). Toner image transfer, fixing, and cleaning of the photoreceptor surface. That is, at least charging, exposure, development, and transfer are repeated. In particular, after the image carrier is operated at a linear speed of 500 mm / s or more, the toner image developed on the image carrier is directly transferred to the transfer body, and the toner image is transferred to the transfer body. The image is formed such that the surface potential polarity of the image carrier is opposite to the polarity at the time of charging.

Here, one embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings.
FIG. 2 is a schematic diagram illustrating a configuration example of an image forming apparatus according to the present invention. In FIG. 2, an image carrier (1) comprises, on a conductive support, a charge generation layer, a charge transport layer, and a trifunctional or higher functional radical polymerizable compound that does not have at least a charge transport structure, and a charge transport layer. It has a surface protective layer made of a cross-linked curable resin that is a reaction product with a monofunctional radically polymerizable compound having a crystalline structure. The ratio (t ₂ / t ₁ ) of the thickness (t ₂ ) of the surface protective layer to the thickness (t ₁ ) of the charge transport layer is adjusted to 0.7 to 1.3.

  A charging charger (3) is used as a means for charging the image carrier on average. As the charging means, a corotron device, a scorotron device, a solid discharge element, a needle electrode device, a roller charging device, a conductive brush device, or the like is used, and a known method can be used.

  Next, the image exposure unit (5) is used to form an electrostatic latent image on the uniformly charged image carrier (1). As the light source, all luminescent materials such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL) can be used. Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.

  Next, the developing unit (6) is used to visualize the electrostatic latent image formed on the image carrier (1). Development methods include a one-component development method using a dry toner, a two-component development method, and a wet development method using a wet toner. When a positive (negative) charge is applied to the image carrier (photoconductor) and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photoconductor. A positive image can be obtained by developing this with negative (positive) toner (electrodetection fine particles), and a negative image can be obtained by developing with positive (negative) toner.

  Next, a transfer charger (10) is used to transfer the toner image visualized on the image carrier onto a transfer body (transfer paper) (9). In addition, a pre-transfer charger (7) may be used for better transfer. As these transfer means, a transfer roller, a transfer belt, and the like can be used in addition to the transfer charger.

  In the present invention, the toner image developed on the image carrier operating at a linear speed of 500 mm / s or more is directly transferred to the transfer member, and the toner image is transferred to the transfer member. It is desirable that the image forming apparatus has a surface potential polarity opposite to the polarity at the time of charging. As a result, the developing toner on the image carrier that operates at high speed can be efficiently transferred to the transfer target, and the surface protective layer of the image carrier of the present invention can be used as a charge transport layer or Since the flow of charge into the charge generation layer or the like is prevented, no afterimage is generated even when the paper is repeatedly passed over a long period of time, and a good image can be provided.

  Next, a separation charger (11) and a separation claw (12) are used as means for separating the transfer body (9) from the image carrier (1). As other separation means, electrostatic adsorption induction separation, side end belt separation, tip grip conveyance, curvature separation, and the like are used. As the separation charger (11), the charging means can be used.

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

Next, static elimination means is used for the purpose of removing the latent image on the image carrier as required. As the charge removal means, a charge removal lamp (2) and a charge removal charger are used, and the exposure light source and the charging means can be used respectively.
In addition, known processes such as document reading, paper feeding, fixing, and paper ejection that are not close to the image carrier can be used.

  The present invention is an image forming apparatus using the image carrier according to the present invention for such image forming means. The image forming means may be fixedly incorporated in a copying apparatus, facsimile, or printer, but may be incorporated in these apparatuses in the form of a process cartridge and detachable. An example of the process cartridge for the image forming apparatus is shown in the schematic diagram of FIG.

  The process cartridge for the image forming apparatus includes an image carrier (101), and in addition, a charging unit (102), a developing unit (104), a transfer unit (106), a cleaning unit (107), and a charge eliminating unit (FIG. And an apparatus (part) that is detachable from the main body of the image forming apparatus.

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

  The present invention provides a process cartridge for an image forming apparatus in which the image carrier according to the present invention and at least one of charging, developing, transferring, cleaning, and charge eliminating means are integrated.

  As is apparent from the above description, the image carrier according to the present invention of the present invention is not only used in an electrophotographic copying machine but also electrophotographic such as a laser beam printer, a CRT printer, an LED printer, a liquid crystal printer, and a laser plate making. It can be widely used in application fields.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not restrict | limited by these Examples. “Parts” are all parts by weight.

The monofunctional radically polymerizable compound having a charge transporting structure used for the formulation of the surface protective layer coating liquid of the following examples was synthesized as follows.
(Synthesis Example 1)
<Synthesis Example of Compound Having Monofunctional Charge Transporting Structure; Synthesis of 54>
(1) Synthesis of hydroxy group-substituted triarylamine compound:
To 113.85 g (0.3 mol) of a methoxy group-substituted triarylamine compound represented by the following structural formula (A) and 138 g (0.92 mol) of sodium iodide, 240 ml of sulfolane is added and heated to 60 ° C. in a nitrogen stream. did.

  99 g (0.91 mol) of trimethylchlorosilane was dropped into the above solution over 1 hour, and the reaction was terminated by stirring for 4 hours and a half at a temperature of about 60 ° C. About 1.5 liters of toluene was added to the reaction solution, cooled to room temperature, and washed repeatedly with water and an aqueous sodium carbonate solution. Thereafter, the solvent was removed from the toluene solution and purified by column chromatography (adsorption medium: silica gel, developing solvent: toluene: ethyl acetate = 20: 1). . Cyclohexane was added to the obtained pale yellow oil to precipitate crystals. In this way, a hydroxy group-substituted triarylamine compound represented by the following structural formula (B) was obtained.

  The obtained hydroxy group-substituted triarylamine compound of the structural formula (B) was 88.1 g (yield = 80.4%), was a white crystal, and had a melting point of 64.0 to 66.0 ° C. It was. The results of elemental analysis are shown in Table 13 below. The measured value and the calculated value were in good agreement, confirming that it was the target product.

(2) Synthesis of triarylamino group-substituted acrylate compound (Exemplary Compound No. 54):
82.9 g (0.227 mol) of the hydroxy group-substituted triarylamine compound [Structural Formula (B)] obtained in (1) above was dissolved in 400 ml of tetrahydrofuran, and an aqueous sodium hydroxide solution (NaOH: 12.2) in a nitrogen stream. 4 g, water: 100 ml) was added dropwise. The solution was cooled to 5 ° C., and 25.2 g (0.272 mol) of acrylic acid chloride was added dropwise over 40 minutes. Then, it stirred at 5 degreeC for 3 hours, and reaction was complete | finished. The reaction solution was poured into water and extracted with toluene. This extract was repeatedly washed with an aqueous sodium bicarbonate solution and water. Thereafter, the solvent was removed from the toluene solution and purified by column chromatography (adsorption medium: silica gel, developing solvent: toluene). N-Hexane was added to the obtained colorless oil, and crystals were precipitated. A compound having 54 charge transporting structures was obtained.
The obtained compound was 80.73 g (yield = 84.8%), and had white crystals and a melting point of 117.5 to 119.0 ° C. The results of elemental analysis are shown in Table 14 below. The measured value and the calculated value were in good agreement, confirming that it was the target product.

(Example 1)
An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following composition are sequentially applied onto an aluminum cylinder by dip coating and dried to obtain a 3.5 μm undercoat layer, 0. A 2 μm charge generation layer and a 15 μm charge transport layer were sequentially formed.

[Undercoat layer coating solution]
Alkyd resin (Beccosol 1307-60-EL, manufactured by Dainippon Ink and Chemicals): 6 parts Melamine resin (Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals): 4 parts Titanium oxide: 40 parts Methyl ethyl ketone: 50 Part

[Charge generation layer coating solution]
Titanyl phthalocyanine pigment: 1.5 parts Polyvinyl acetal (BM-S, manufactured by Sekisui Chemical Co., Ltd.): 0.5 parts Methyl ethyl ketone: 70 parts

[Charge transport layer coating solution]
Bisphenol Z-type polycarbonate (Panlite TS-2050, manufactured by Teijin Chemicals): 10 parts
Charge transport compound (Compound No. BTA-08): 10 parts
Tetrahydrofuran: 100 parts
1% silicone oil in tetrahydrofuran
(KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.): 1 part

Further, spray coating is performed on the charge transport layer using a surface protective layer coating solution having the following composition, and light irradiation is performed under the conditions of a metal halide lamp, irradiation intensity: 500 mW / cm ² , irradiation time: 240 seconds, After drying at 130 ° C. for 30 minutes, a 15 μm surface protective layer was provided to prepare an image bearing member (electrophotographic photosensitive member).

[Surface protective layer coating solution]
Radical polymerizable monomer having no charge transporting structure Trimethylolpropane triacrylate of the following structural formula (VI)
(TMPTA, manufactured by Tokyo Chemical Industry): 55 parts

40 parts of alkyl-modified dipentaerythritol pentaacrylate of the following structural formula (VII) (KAYARAD D-310, manufactured by Nippon Kayaku)

Monofunctional radically polymerizable compound having a charge transporting structure synthesized in Synthesis Example 1 (Exemplary Compound No. 54): 95 parts Photopolymerization initiator [1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, Ciba Specialty)・ Chemicals)]: 10 parts Tetrahydrofuran: 1200 parts

(Example 2)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the film thickness of the surface protective layer was changed to 19 μm in Example 1.

(Example 3)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the thickness of the surface protective layer was changed to 11 μm in Example 1.

Example 4
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the thickness of the charge transport layer was changed to 20 μm in Example 1.

(Example 5)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the thickness of the charge transport layer was changed to 12 μm in Example 1.

(Example 6)
Except that the charge transport layer compound (Compound No. BTA-08) used in the composition of the charge transport layer coating solution in Example 1 was Compound No. BTA-20 and the amount of the composition was 10 parts, all the same as Example 1. Thus, an electrophotographic photosensitive member was prepared.

(Example 7)
Except that the charge transport layer compound (Compound No. BTA-08) used for the composition of the charge transport layer coating solution in Example 1 was Compound No. BTA-78 and the amount of the composition was 10 parts, all the same as Example 1. Thus, an electrophotographic photosensitive member was prepared.

(Example 8)
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the charge transport layer compound (Compound No. BTA-08) used in the composition of the charge transport layer coating solution in Example 1 was changed to the following.
Charge transport compound (Compound No. BTA-08): 7 parts
Charge transport compound (specific example No. II-6): 3 parts

Example 9
Example 1 except that the thickness of the surface protective layer was changed to 19 μm in Example 1 and the charge transport layer compound (Compound No. BTA-08) used in the composition of the charge transport layer coating solution was changed to the following. An electrophotographic photoreceptor was prepared in the same manner as described above.
Charge transport compound (Compound No. BTA-08): 7 parts
Charge transport compound (specific example No. II-6): 3 parts

(Example 10)
Example 1 except that the thickness of the surface protective layer was changed to 11 μm in Example 1 and the charge transport layer compound (Compound No. BTA-08) used in the composition of the charge transport layer coating solution was changed to the following. An electrophotographic photoreceptor was prepared in the same manner as described above.
Charge transport compound (Compound No. BTA-08): 7 parts
Charge transport compound (specific example No. II-6): 3 parts

(Example 11)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the charge generation layer coating solution in Example 1 was changed as follows.
[Charge generation layer coating solution]
Titanylphthalocyanine pigment: 1.0 part Disazo pigment of the following structural formula (C): 1.0 part Polyvinyl acetal (BM-S, manufactured by Sekisui Chemical Co., Ltd.): 0.8 part Methyl ethyl ketone: 30 parts Cyclohexanone: 40 parts

(Example 12)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the charge generation layer coating solution in Example 1 was changed as follows.
[Charge generation layer coating solution]
Gallium phthalocyanine pigment: 1.5 parts Polyvinyl acetal (BM-S, manufactured by Sekisui Chemical Co., Ltd.): 0.5 parts Methyl ethyl ketone: 70 parts

(Comparative Example 1)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the thickness of the surface protective layer was changed to 22 μm in Example 1.

(Comparative Example 2)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the thickness of the surface protective layer was changed to 8 μm in Example 1.

(Comparative Example 3)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the thickness of the charge transport layer was changed to 25 μm in Example 1.

(Comparative Example 4)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the thickness of the charge transport layer was changed to 10 μm in Example 1.

(Comparative Example 5)
The charge transport layer compound (Compound No. BTA-08) used in the composition of the charge transport layer coating solution in Example 1 was prepared according to the specific example No. An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that II-6 was used and the composition amount was 10 parts.

(Comparative Example 6)
Example 1 except that the charge transport layer compound (Compound No. BTA-08) used in the composition of the charge transport layer coating solution in Example 1 was represented by the following structural formula (D) and the composition content was 10 parts. An electrophotographic photoreceptor was prepared in the same manner as described above.

  The electrophotographic photosensitive member produced as described above is mounted on an electrophotographic process cartridge and subjected to a continuous paper endurance test for a total of 1 million sheets using Ricoh's imagio Neo 1050Pro. Was evaluated. The results are shown in Table 15 below.

  As is apparent from the results in Table 15, the image carrier (electrophotographic photosensitive member) of the present invention shown in the examples is able to maintain high-quality image output even after passing 1 million sheets. I understand.

(Examples 13 to 17)
Next, Imagio Neo 1050 Pro manufactured by Ricoh, an image forming apparatus that directly transfers the toner image developed on the photoconductor to paper, has been modified so that the linear velocity and transfer current can be changed. Further, surface potential meters were attached to the downstream side of the charger and the downstream side of the cleaning blade so that the surface potential of the photoconductor can be measured immediately after charging and after the toner image is transferred to paper.

  Subsequently, the photosensitive member of Example 1 after carrying out the above-described evaluation for passing 1 million sheets was mounted on an electrophotographic process cartridge, and the linear velocity was changed using the Ricoh imagio Neo 1050Pro modified as described above. Further, the surface potential of the photoconductor was measured when the transfer current was changed, and the output image was visually evaluated. The results are shown in Table 16 below.

  As is apparent from the results in Table 16, the toner image developed on the electrophotographic photosensitive member of the present invention operating at a linear speed of 500 mm / s or more was directly transferred to paper, and the toner image was transferred to paper. It can be seen that all the image forming apparatuses in which the surface potential polarity of the photoconductor is opposite to the polarity at the time of charging can maintain the high-quality image output even after passing 1 million sheets.

As is apparent from the above, according to the image carrier of the present invention, the wear resistance is high, the electrical characteristics are good, the durability is maintained over a long period of time, and even after passing 1 million sheets at a high speed. Therefore, an abnormal image due to an afterimage or the like is not generated, and a high-resolution image can be output.
Therefore, if the image carrier of the present invention is used in an image forming apparatus, an image forming method, or a process cartridge for an image forming apparatus, it is possible to meet demands for high linear velocity and printing of a large number of sheets.

It is sectional drawing which shows an example (A) and (B) of the layer structure of the image carrier in this invention. 1 is a schematic diagram illustrating a configuration example of an image forming apparatus according to the present invention. FIG. 2 is a schematic diagram illustrating an example of a process cartridge for an image forming apparatus according to the present invention.

Explanation of symbols

1 Image carrier
2 Static elimination lamp
3 Charger charger
4 Eraser
5 Image exposure section
6 Development unit
7 Charger before transfer
8 Registration roller
9 Transfer body (transfer paper)
10 Transfer Charger 11 Separation Charger 12 Separation Claw
13 Charger before cleaning
14 Fur brush
15 Cleaning blade
31 Conductive support 33 Intermediate layer (undercoat layer)
35 charge generation layer 37 charge transport layer 39 surface protective layer 101 image carrier 102 charging means 103 exposure means
104 Developing means
105 Transfer body 106 Transfer means 107 Cleaning means

Claims (15)

In an image carrier having a charge generation layer, a charge transport layer, and a surface protective layer on a conductive support,
The charge transport layer contains a compound represented by the following general formula (I), and the surface protective layer has at least a trifunctional or higher-functional radical polymerizable compound having no charge transport structure, and 1 having a charge transport structure. The ratio (t ₂ / t ₁ ) of the film thickness (t ₂ ) of the surface protective layer to the film thickness (t ₁ ) of the charge transport layer, comprising a cross-linked curable resin that is a reaction product with a functional radical polymerizable compound Is an image bearing member, wherein the image bearing member is 0.7 to 1.3.

[In the general formula (I), R ₇ , R ₈ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ may be the same or different and each represents a hydrogen atom, a lower alkyl group, an alkoxy group, A phenoxy group, a halogen atom or an optionally substituted aryl group is shown, and p ¹ and p ^{2 each} represents 0 or 1. Z is a hydrogen atom, a lower alkyl group, an alkoxy group, a phenoxy group, a halogen atom, an aryl group which may have a substituent, or the following general formulas (Za), (Zb), (Zc):

(Wherein R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ and p ¹ and p ² are the same as those shown in the general formula (I), and R ₁₄ and R ₁₅ are the same or different. Or a hydrogen atom, a lower alkyl group, an alkoxy group, a phenoxy group, a halogen atom or an aryl group which may be substituted, and p ³ represents 0 or 1. ] _2. The image bearing member according to claim 1, wherein the surface protective layer has a thickness (t ₂ ) of 10 μm to 20 μm. The image carrier according to claim 1, wherein the charge transport layer contains a compound represented by the following general formula (II) in addition to the compound represented by the general formula (I).

(In the general formula (II), Ar ₁ and Ar ₂ represent a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic group, and R ₁ , R ₂ and R ₃ are hydrogen atoms, substituted or unsubstituted. Represents an alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, R ₂ and R ₃ may be bonded to each other to form a ring, Ar ₃ represents a substituted or unsubstituted arylene group, and n represents 0 or 1.)   The image carrier according to any one of claims 1 to 3, wherein the charge generation layer contains a titanyl phthalocyanine pigment.   The image carrier according to any one of claims 1 to 3, wherein the charge generation layer contains a titanyl phthalocyanine pigment and a disazo pigment.   6. The image carrier according to claim 1, wherein a functional group of the monofunctional radically polymerizable compound having a charge transporting structure is an acryloyloxy group or a methacryloyloxy group.   The image carrier according to claim 1, wherein the monofunctional radically polymerizable compound having a charge transporting structure has a triarylamine structure as a charge transporting structure. The monofunctional radically polymerizable compound having the triarylamine structure is one or more radically polymerizable compounds represented by the following general formula (1) or (2): An image carrier according to any one of the above.

[In the formulas (1) and (2), R ₁ may have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Aryl group, cyano group, nitro group, alkoxy group, —COOR ₇ (R ₇ has a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. May be an aryl group), a carbonyl halide group or CONR ₈ R ₉ (R ₈ and R ₉ are a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl which may have a substituent) Represents an aryl group which may have a group or a substituent, and may be the same or different from each other), Ar ₁ and Ar ₂ represent a substituted or unsubstituted arylene group, and May be different. Ar ₃ and Ar ₄ represent a substituted or unsubstituted aryl group, and may be the same or different. X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group. Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group, or an alkyleneoxycarbonyl group. m and n represent an integer of 0 to 3. ] The image carrier according to claim 7 or 8, wherein the monofunctional radically polymerizable compound having a triarylamine structure is one or more radically polymerizable compounds represented by the following general formula (3). .

[In the formula (3), o, p and q are each an integer of 0 or 1; Ra represents a hydrogen atom or a methyl group; Rb and Rc represent an alkyl group having 1 to 6 carbon atoms; May be. s and t represent an integer of 0 to 3. Za represents a single bond, a methylene group, an ethylene group, or a divalent group represented by the following formulas (4), (5), and (6). ]

  10. The image bearing member according to claim 1, wherein the curing means for the cross-linked curable resin forming the surface protective layer is by heating or light energy irradiation.   An image forming apparatus comprising at least the image carrier according to any one of claims 1 to 10, a charging unit, an exposure unit, a developing unit, and a transfer unit.   The image forming apparatus according to claim 11, wherein the image carrier is configured to operate at a linear velocity of 500 mm / s or more.   An image bearing member according to any one of claims 1 to 10, and at least one means selected from the group consisting of a charging means, a developing means, a transfer means, a cleaning means, and a charge eliminating means, A process cartridge which is configured to be detachable.   An image forming apparatus comprising the process cartridge according to claim 13. An image forming method using the image forming apparatus according to claim 11, wherein at least charging, exposure, development and transfer are repeated.
The image carrier after the image carrier is operated at a linear speed of 500 mm / s or more, the toner image developed on the image carrier is directly transferred to the transfer body, and the toner image is transferred to the transfer body. An image forming method characterized in that an image is formed so that the surface potential polarity of the electrode has a polarity opposite to that at the time of charging.

Images