JP2005331881A - Dispersion treatment method for liquid containing fine metal oxide particles, electrophotographic photoreceptor and method for manufacturing the same, electrophotographic apparatus, and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dispersion treatment method, by which, in the dispersion treatment of a liquid containing fine metal oxide particles, the fine metal oxide particles can be efficiently and surely dispersed, while suppressing degeneration of the particles. <P>SOLUTION: In the method with which a dispersion treatment of the liquid to be treated containing the fine metal oxide particles is performed, by using a horizontal media milling dispersion machine 1 equipped with a cylinder 3 storing media 2, a stirring mill 5 disposed in the cylinder 3 and rotatably centered about a rotation shaft 4 in approximately the horizontal direction, the liquid to be treated is circulated in the cylinder 3 along the rotation shaft 4 direction; while the stirring mill 5 is kept rotated and the media 2 are mal-distributed on the downstream side in the cylinder 3, to form a media layer 40 on an inner wall 9b on the downstream side in the cylinder 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a dispersion treatment method for a liquid to be treated containing metal oxide fine particles, an electrophotographic photosensitive member and a method for producing the same, an electrophotographic apparatus, and a process cartridge.

  In an electrophotographic apparatus such as a copying machine or a laser beam printer, an electrophotographic system capable of obtaining high-speed and high-quality printing is used. As an electrophotographic photoreceptor used in such an electrophotographic apparatus, an organic photoreceptor using an organic material having photoconductivity is mainly used. In addition, from the viewpoint of performance, the structure of the photoconductor in which the photosensitive layer is provided on the substrate is also different from the single layer type photoconductor in which the photoconductive layer includes a layer containing both the charge generation material and the charge transport material. The layer is changed to a function-separated type photoreceptor in which a layer containing a generating material (charge generating layer) and a layer containing a charge transporting material (charge transporting layer) are separately provided in the photosensitive layer.

  In the case of a function-separated type photoreceptor, an undercoat layer is often provided between the substrate and the photosensitive layer for the purpose of preventing charge injection from the substrate to the photosensitive layer. An example of the undercoat layer is one in which metal oxide fine particles are dispersed in a binder resin.

  Such an undercoat layer can be formed by applying a coating liquid containing metal oxide fine particles and a binder resin on a substrate and drying it. In general, this type of undercoat layer forming method uses a medium such as glass beads after dissolving the metal oxide fine particles and the binder resin in a solvent for the purpose of enhancing the dispersibility of the metal oxide fine particles. An undercoat layer coating solution is prepared by performing a dispersion process using a dispersing means such as a media mill. However, conventionally used dispersion processing methods have a large dispersion in the dispersion state of metal oxide fine particles, and it has been difficult to stably produce an electrophotographic photosensitive member.

In view of this, studies are being made on techniques for increasing the dispersibility of metal oxide fine particles in a coating solution. For example, as a proposal for improving a liquid to be treated for dispersion treatment, a method has been proposed in which the component ratio of the liquid to be treated is adjusted to lower the viscosity of the liquid to be treated and the dispersion treatment is performed with a media mill. According to this, since the freedom degree of media increases, it is thought that metal oxide fine particles become easy to be disperse | distributed with media. As a proposal for improving the dispersing means, a method has been proposed in which a circulation device is provided outside the dispersing means to disperse the liquid to be treated while circulating (for example, Patent Document 1).
JP 2000-56484 A

  However, there is still room for improvement in order to obtain good image quality even with an electrophotographic photoreceptor having an undercoat layer formed using the above-described dispersion processing method.

  More specifically, in the case of the above-described function-separated type photoconductor, if the residual potential in the photoconductor increases due to repeated use, the contrast of the electrostatic latent image deteriorates and image quality defects tend to occur. For this reason, the function-separated type photoreceptor is required to have repetitive stability and environmental stability (temperature, humidity, etc.) during repeated use, but these characteristics are not limited to the charge generation layer and the charge transport layer. Depends on the physical properties of the stratum Therefore, the undercoat layer is required to have electrical characteristics (hereinafter simply referred to as “electrical characteristics”) that reduce charge accumulation due to repeated use due to appropriate charge transport capability.

  In addition, when a locally deteriorated portion exists in the photoconductor, a local high electric field is applied to the deteriorated portion at the time of contact charging, and an electrical pinhole is generated in the photoconductor. The pinhole causes a latent image charge to pass to the photoreceptor substrate, which causes so-called charge leakage, and image quality defects are likely to occur. This pinhole leak is generally caused by a coating film defect in the photosensitive layer. In addition, for example, conductive foreign matter (carbon fiber, carrier powder, etc.) generated from the inside of the electrophotographic apparatus contacts or penetrates into the photoconductor, and the contact charging device and the photoconductor substrate are caused by the foreign matter. If the conductive path is easily formed, pinholes are likely to occur during contact charging, and pinhole leakage may occur. In particular, a foreign matter mixed from other members in the electrophotographic apparatus or dust mixed in the electrophotographic pierced the photoconductor, and pinhole leakage may occur from there. Therefore, the undercoat layer is required to have a charge leak preventive property (hereinafter simply referred to as “leak preventive property”) due to pinholes in addition to the electrical characteristics described above.

  However, the electrophotographic photosensitive member provided with the undercoat layer formed by lowering the viscosity of the conventional liquid to be processed and the electrophotographic photosensitive member provided with the undercoat layer formed by the method described in Patent Document 1 have these two characteristics. It is difficult to get enough.

  Therefore, the present inventors examined the correlation between the dispersion method in the undercoat layer in which the metal oxide fine particles are dispersed, the electrical characteristics, and the leak prevention properties. In the conventional dispersion treatment method, the electrical characteristics are as follows. It was found that it is difficult to improve both the anti-leakage and the leak-proofing property in a balanced manner. For example, if a dispersion treatment is performed under high shear conditions in order to efficiently increase the dispersibility of metal oxide fine particles, the metal oxide fine particles and other materials are physically or chemically destroyed, and defects are easily formed. , Making it easy to cause deterioration of material properties and image quality defects. On the other hand, when the dispersion treatment is performed under a low shear condition, alteration of the metal oxide fine particles due to shearing is suppressed, but the dispersibility of the metal oxide fine particles tends to be insufficient, so that it is difficult to obtain a desired dispersion state. That is, in the conventional distributed processing method, even if the process is performed under either high shear or low shear conditions, the resulting subbing layer tends to be locally biased in volume resistance, and has a large volume resistance. If this occurs, sufficient electrical characteristics cannot be obtained, and if a region with a small volume resistance is produced, sufficient leak prevention cannot be obtained.

  From the above points, in order to achieve both the electrical characteristics and the leak prevention property in the undercoat layer, not only the dispersibility of the metal oxide fine particles but also the metal oxide fine particles due to shearing during the dispersion treatment at the same time It is important to suppress the alteration of

  The present invention has been made in view of such circumstances, and when dispersing a treatment liquid containing metal oxide fine particles, the fine particles can be efficiently and reliably suppressed while sufficiently suppressing the deterioration of the metal oxide fine particles. It is an object of the present invention to provide a distributed processing method that can be distributed in a distributed manner. The present invention also provides a method for producing an electrophotographic photosensitive member using such a dispersion processing method, an electrophotographic photosensitive member obtained thereby, and an electrophotographic apparatus and a process cartridge using the electrophotographic photosensitive member. With the goal.

  In order to solve the above problems, a dispersion processing method of the present invention is a horizontal medium comprising a cylinder in which a medium is accommodated, and an agitation mill provided in the cylinder and rotatable about a substantially horizontal rotation axis. A method of dispersing a treatment liquid containing metal oxide fine particles using a mill disperser, wherein the treatment liquid is circulated in a cylinder along a rotation axis direction while rotating a stirring mill, Is distributed unevenly on the downstream side in the cylinder, and a media layer is formed on the inner wall on the downstream side in the cylinder.

  Here, the “downstream side” means the side in the cylinder where the liquid to be processed flows out of the cylinder, and the “downstream inner wall in the cylinder” means the liquid to be processed flowing in the cylinder. Refers to the inner wall that abuts before flowing out of the cylinder (hereinafter, the side where the liquid to be treated flows into the cylinder corresponds to the downstream side is referred to as the “upstream side”). The “media layer” refers to a layer formed by densely existing media.

  The dispersion treatment method of the present invention uses a horizontal media mill disperser as a dispersing means, and when the liquid to be treated containing metal oxide fine particles flows through the cylinder, the liquid to be treated is glass beads or the like. The dispersion treatment is performed by stirring together with the media in a stirring mill. At this time, the ratio of the media is low in the upstream region in the cylinder, while the media layer is formed on the downstream side, so the degree of freedom of the media is relatively small, and the conditions for stirring the liquid to be processed by the media are low. Mild throughout the cylinder. For this reason, the metal oxide fine particles in the liquid to be treated and the media collide with each other, the heat generated by the collision between the media or the cylinder inner wall and the media, and the wear of the cylinder inner wall by the media are less likely to occur. It is possible to sufficiently suppress alteration and contamination of the wear powder into the liquid to be treated. In the media layer formed on the downstream side, the liquid to be treated is gently agitated by the dense media, so that the metal oxide fine particles can be sufficiently uniformly dispersed in the liquid to be treated.

  Note that the above-described media distribution in the present invention is different from the media distribution generally considered desirable in the dispersion processing method using the horizontal media mill disperser, and the resulting effect is extremely unexpected. It can be said that. In other words, in the case of a conventional dispersion processing method using a horizontal media mill disperser, if the share is lowered in order to make the stirring conditions mild, a very small area of the media is generated in the upper part of the cylinder due to sedimentation of the media, and the like. A phenomenon that the treatment liquid passes through the region without being sufficiently stirred (hereinafter referred to as “short path”) is likely to occur. Therefore, in order to improve the dispersibility, it was thought that it was necessary to keep the media uniformly in the cylinder and to increase the share. However, if the share is increased, the metal oxide fine particles are likely to be altered. Is as described above. On the other hand, according to the dispersion treatment method of the present invention, the metal oxide fine particles are mildly and sufficiently dispersed in the liquid to be treated by forming the media layer by unevenly distributing the media downstream in the cylinder. It is possible to realize the stirring conditions for causing Then, by using the liquid to be treated thus obtained as a coating liquid for forming the undercoat layer of the electrophotographic photosensitive member, both the anti-leakage property and the electrical characteristics are imparted to the undercoat layer in a well-balanced and sufficient manner. It becomes possible.

  Further, in the present invention, the liquid to be treated is circulated in the cylinder along the rotation axis direction while rotating the stirring mill so that the medium is accumulated on the entire inner wall on the downstream side of the cylinder when viewed from the rotation axis direction. The medium is preferably unevenly distributed on the downstream side of the cylinder. As a result, a media layer that is densely filled with media is formed on the downstream side of the cylinder from the top to the bottom of the cylinder (hereinafter referred to as “bead packing”). The movement of the media can be controlled at a low speed and uniformly. When such a media layer is formed, the liquid to be treated always passes through the media layer, so that a short path of the liquid to be treated can be more reliably prevented, and the alteration of the metal oxide fine particles can be prevented. Suppression and improvement of the dispersibility of the fine particles can be achieved at a higher level.

  Moreover, in this invention, it is preferable that the viscosity of a to-be-processed liquid shall be 10 mPa * s or more and the flow volume of a to-be-processed liquid shall be 800 mL / min or more in a cylinder. By making the viscosity and flow rate of the liquid to be treated satisfy the above-mentioned conditions, bead packing is likely to occur on the downstream side in the cylinder, so that the deterioration of the metal oxide fine particles is suppressed and the dispersibility of the fine particles is improved. Can be achieved at a higher level.

Further, in the present invention, the cylinder is substantially cylindrical hollow, and the stirring mill is provided so that the rotation axis thereof is substantially horizontal with respect to the center axis of the cylinder. The inner diameter of the following formula (1):
L / D ≧ 2 (1)
It is preferable that the condition represented by Here, in Formula (1), L represents the length (mm) of the cylinder in the central axis direction, and D represents the inner diameter (mm) of the cylinder.

  Thus, by using a horizontal media mill disperser in which the length and inner diameter in the central axis direction of the cylinder satisfy the above conditions, bead packing is more likely to occur on the downstream side in the cylinder. In addition, since the thickness of the media layer as viewed from the rotation axis direction of the stirring mill is increased, it is possible to more reliably prevent a short pass of the liquid to be processed. Therefore, it is possible to achieve the suppression of the alteration of the metal oxide fine particles and the improvement of the dispersibility of the fine particles at an even higher level.

Further, in the present invention, the cylinder is substantially cylindrical hollow, and the stirring mill is provided so that the rotation axis thereof is substantially horizontal with respect to the center axis of the cylinder. The inner diameter of the cylinder and the flow rate of the liquid to be treated in the cylinder are expressed by the following formula (2):
D ² L / 1273V ≦ 2.5 (2)
It is preferable that the condition represented by Here, in formula (2), L represents the length (mm) in the central axis direction of the cylinder, D represents the inner diameter (mm) of the cylinder, and V represents the flow rate of the liquid to be treated in the cylinder (mL / min). ).

  When the length in the central axis direction of the cylinder, the inner diameter of the cylinder, and the flow rate of the liquid to be treated in the cylinder satisfy the condition expressed by the above formula (2), the length in the central axis direction of the cylinder and the inner diameter of the cylinder In contrast, the flow rate of the liquid to be processed in the cylinder can be adjusted to a flow rate at which bead packing is likely to occur. That is, since the liquid to be processed flows at an optimum speed considering the shape of the cylinder to be used, bead packing is more likely to occur on the downstream side in the cylinder. As a result, it is possible to achieve a very high level of suppression of alteration of the metal oxide fine particles and improvement of the dispersibility of the fine particles.

  In the present invention, as a horizontal type media mill disperser, a disperser body provided with a cylinder and a stirring mill, a container for storing a dispersion to be supplied to the cylinder, and a liquid to be processed flowing out from the cylinder after the dispersion treatment are returned to the container. It is preferable to disperse the liquid to be treated by a circulation method using a disperser having a flow path. In this case, the degree of dispersion can be controlled by the time during which the liquid to be treated is present in the cylinder or the number of times the liquid to be treated passes through the cylinder. In particular, when the condition expressed by the above equation (2) is satisfied, the flow rate of the liquid to be treated with respect to the cylinder capacity is relatively large, and the number of times the cylinder passes through the fixed time increases. Can be made uniform.

  In addition, the method for producing an electrophotographic photosensitive member of the present invention is a method for producing an electrophotographic photosensitive member in which an undercoat layer and a photosensitive layer are provided in this order on a conductive substrate. An undercoat layer coating solution preparation step for obtaining an undercoat layer coating solution by performing a dispersion treatment by the above-described dispersion treatment method of the present invention, and coating the undercoat layer coating solution on a substrate, containing metal oxide fine particles An undercoat layer forming step of forming an undercoat layer.

  The electrophotographic photosensitive member of the present invention is obtained by the production method of the present invention.

  Thus, by forming the undercoat layer using the coating solution dispersed by the dispersion treatment method of the present invention, physical or chemical alteration of the metal oxide fine particles is sufficiently suppressed, and the fine particles Since it is sufficiently uniformly dispersed in the undercoat layer, it is possible to improve both the electrical properties and the leak prevention properties of the undercoat layer in a well-balanced manner and to obtain a good image quality over a long period of time. Is feasible.

  In the present invention, it is preferable that the metal oxide fine particles are surface-treated with a silane coupling agent. By using the metal oxide fine particles treated with the silane coupling agent, the dispersibility of the metal oxide fine particles in the binder resin can be improved, so that the electrical properties and leakage prevention properties of the undercoat layer can be further improved. it can. Further, the bulk resistance of the metal oxide fine particles can also be adjusted by the degree of surface treatment of the metal oxide fine particles with a silane coupling agent (amount etc.). For example, when the undercoat layer has a single layer structure, the charge resistance at the interface between the undercoat layer and the charge generation layer is higher than that of the multilayer structure. It is easy to be influenced by. For this reason, in such a case, a metal having an optimum bulk resistance is considered in consideration of the coexistence of this charge injection preventing property that requires a moderate resistance and electrical characteristics that require a moderate charge transport capability. Although it is preferable to use oxide fine particles, the above adjustment can facilitate the coexistence of these characteristics.

  In particular, in the dispersion treatment method of the present invention, the liquid to be treated can be dispersed so as not to physically or chemically damage the material such as metal oxide fine particles. Even if the surface treatment is performed with the silane coupling agent, the dispersion treatment can be performed so that the silane coupling agent does not peel off from the metal oxide fine particles during the dispersion treatment.

  The electrophotographic apparatus of the present invention includes the electrophotographic photosensitive member of the present invention, a charging device that charges the electrophotographic photosensitive member, and an exposure device that exposes the charged electrophotographic photosensitive member to form an electrostatic latent image. And a developing device that develops the electrostatic latent image to form a toner image, and a transfer device that transfers the toner image from the electrophotographic photosensitive member to a transfer medium.

  The process cartridge of the present invention includes an electrophotographic photosensitive member of the present invention, a charging device for charging the electrophotographic photosensitive member, an exposure device for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image, and a static device. Select from a developing device that develops an electrostatic latent image to form a toner image, a transfer device that transfers the toner image from the electrophotographic photosensitive member to a transfer medium, and a cleaning device that removes deposits from the electrophotographic photosensitive member after transfer. And at least one kind.

  In the electrophotographic apparatus and process cartridge of the present invention, image defects such as fogging and ghosting and sensitivity fluctuations are caused by using the electrophotographic photosensitive member of the present invention having an undercoat layer excellent in electrical characteristics and leak prevention properties. Therefore, good image quality can be obtained over a long period of time.

  According to the present invention, there is provided a dispersion treatment method capable of efficiently and reliably dispersing fine particles while suppressing alteration of the metal oxide fine particles when the treatment liquid containing the metal oxide fine particles is dispersed. Can be provided. The present invention also provides a method for producing an electrophotographic photosensitive member using such a dispersion processing method, an electrophotographic photosensitive member obtained thereby, and an electrophotographic apparatus and a process cartridge using the electrophotographic photosensitive member. Can do.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  First, a preferred embodiment of the dispersion processing method of the present invention will be described, and then each of the preferred embodiments of the present invention will be described in the order of the electrophotographic photosensitive member and the manufacturing method thereof, the electrophotographic apparatus, and the process cartridge. .

(Distributed processing method)
FIG. 1 is an explanatory diagram showing an example of a horizontal media mill disperser preferably used in the present invention. In FIG. 1, a container (treatment liquid tank) 7 contains a treatment liquid 100 containing metal oxide fine particles, and the container 7 is connected to a disperser 1 via a line L1 provided with a liquid feed pump 8. It is connected to (the upstream inner wall 9a of the cylinder 3). Further, on the side opposite to the line L 1 of the cylinder 3, a line L 2 having one end connected to the downstream inner wall 9 b and the other end connected to the container 7 is provided. The metal oxide fine particles contained in the liquid to be treated 100 will be described in detail in the description of the electrophotographic photosensitive member and the manufacturing method thereof, but the fine particles may be surface-treated with a silane coupling agent. .

  The disperser body 1 includes a cylindrical hollow cylinder 3 in which a medium 2 is accommodated, and a stirring mill that is provided in the cylinder 3 and that can rotate around a shaft (rotating shaft) 4 disposed in a substantially horizontal direction. 5 and a drive device 6 that is connected to one end of the shaft 4 and rotates the stirring mill 5.

  The capacity of the cylinder 3 is not particularly limited, but is preferably 0.6 to 60L. The bulk filling rate of the medium 2 is not particularly limited, but is preferably 70 to 85% of the capacity of the cylinder 3.

  The material of the medium 2 is not particularly limited, and specific examples include zirconia, SUS, alumina, glass beads, steel, and chrome steel. Although there is no restriction | limiting in particular about the average particle diameter of the medium 2, 800-2100 micrometer (phi) is preferable.

  The material of the cylinder 3 and the stirring mill 5 is not particularly limited, and examples thereof include ceramics mainly composed of zirconia, alumina, SUS, glass, polyurethane, polyethylene, nylon, and the like, and a material having particularly high hardness is preferable. . Thereby, damage to the media 2, the cylinder 3, the stirring mill 5, etc. can be prevented, and contamination of impurities into the liquid 100 can be prevented. The use of zirconia-based ceramics or alumina is particularly effective when, for example, the rotational speed of the stirring mill 5 is set to 6 m / s or more as described above. If present, SUS or a material covered with an organic resin may be used.

As a horizontal type media mill disperser in the present embodiment, the length 20 in the central axis direction of the cylinder 3 and the inner diameter 21 of the cylinder 3 are represented by the following formula (1):
L / D ≧ 2 (1)
It is preferable to use one that satisfies the condition represented by Here, in Formula (1), L represents the length (mm) of the cylinder in the central axis direction, and D represents the inner diameter (mm) of the cylinder. By using the cylinder 3 satisfying such conditions, it is possible to more easily cause bead packing. From the viewpoint of further improving the dispersibility of the metal oxide fine particles, L / D is more preferably 2.1 or more, and further preferably 2.2 or more.

  When the liquid 100 to be processed is dispersed using such a horizontal type media mill disperser, first, the liquid 100 to be processed contained in the container 7 is drawn out to the line L1 by the pump 8 and the cylinder 3 of the disperser main body 1. It is introduced from the upstream inner wall 9a.

  In the disperser body 1, the liquid 100 to be processed is stirred together with the medium 2 by passing the liquid 100 to be processed through the cylinder 3 along the rotation shaft 4 while rotating the stirring mill 5 by the driving device 6. The liquid 100 to be treated thus dispersed returns from the downstream inner wall 9b of the cylinder 3 to the container 7 through the line L2, and is again subjected to the dispersion treatment.

  When performing such a dispersion treatment, it is preferable that the viscosity of the liquid 100 to be processed is 10 mPa · s or higher and the flow rate of the liquid 100 to be processed in the cylinder 3 is 800 mL / min or higher. From the viewpoint of further improving the dispersibility of the metal oxide fine particles, the viscosity of the liquid to be treated 100 is more preferably 50 mPa · s or more, and further preferably 100 mPa · s or more. Further, the flow rate of the liquid 100 to be treated in the cylinder 3 is more preferably 1000 mL / min or more, and further preferably 1200 mL / min or more.

Further, the flow rate, the length 20 in the central axis direction of the cylinder 3 and the inner diameter 21 of the cylinder 3 are expressed by the following formula (2):
D ² L / 1273V ≦ 2.5 (2)
It is preferable to carry out so as to satisfy the condition represented by Here, in formula (2), L represents the length (mm) in the central axis direction of the cylinder, D represents the inner diameter (mm) of the cylinder, and V represents the flow rate of the liquid to be treated in the cylinder (mL / min). ). From the viewpoint of further improving the dispersibility of the metal oxide fine particles, D ² L / 1273V is more preferably 2.3 or less, and further preferably 2.0 or less.

  The rotation speed (mill moving speed) of the stirring mill 5 is preferably 6 to 20 m / s. When the rotational speed is less than 6 m / s, the media distribution in the cylinder 3 is likely to be biased, and the collision speed between the media 2 is low, so that dispersibility and uniformity tend to be reduced. When the rotational speed exceeds 20 m / s, the share becomes excessively large and the metal oxide fine particles in the liquid 100 to be treated tend to be altered.

  Further, in the present invention, it is preferable to perform the distributed processing by the circulation method as described above. By performing the dispersion treatment by the circulation method, the dispersibility of the metal oxide fine particles can be more reliably improved even when the flow rate of the liquid 100 to be treated is large. Further, since the treated liquid 100 after the dispersion treatment is accommodated in the container 7, the dispersibility of the metal oxide fine particles in the whole treated liquid 100 is made uniform, so that the metal oxide fine particles are highly dispersed. The treatment liquid 100 can be obtained stably. If sufficient dispersibility is obtained by circulating once in the cylinder, the dispersion treatment may be performed by a one-time distribution method, and sufficient dispersibility is obtained if not distributed multiple times in the cylinder. If not, a plurality of cylinders may be connected via a line, and distributed processing may be performed by a plurality of distribution methods.

  Next, the operation of the distributed processing method of this embodiment will be described.

  2A and 2B are graphs conceptually showing an example of media distribution in the cylinder 3 according to the distributed processing method of the present embodiment, and FIGS. 3A, 3B, and 4A. , (B) are graphs conceptually showing an example of media distribution in the cylinder 3 by a conventional distributed processing method. In both cases, the horizontal direction (the flow direction of the liquid 100 to be processed along the rotation axis 4) is the x axis, and the vertical upward direction is the y axis.

  In the present embodiment, by performing the dispersion process as described above, the media 2 is unevenly distributed downstream in the cylinder 3 of the horizontal media mill disperser 1 as shown in FIG. A media layer 40 is formed.

  Thereby, as shown in FIG. 2A, the media distribution in the x-axis direction is in a state of being distributed to the downstream side. Then, a first region 50 of bead packing appears in the media layer 40 on the downstream side. The media in the first area 50 has a small degree of freedom and a very slow moving speed, so that the media distribution in the y-axis direction is uniform as shown in FIG. Become mild.

  When the liquid to be treated is circulated in the cylinder 3 in such a state of media distribution, the liquid to be treated is sufficiently stirred on the downstream side under mild dispersion conditions, so that the alteration of the metal oxide fine particles is suppressed. However, the metal oxide fine particles can be sufficiently dispersed. Further, since the liquid to be treated always passes through the first region 50 of the media layer 40, it is possible to reliably prevent the liquid to be processed from coming out of the cylinder 3 through a short pass.

  Note that, due to the influence that the media distribution is biased toward the downstream side, a second region 60 in which the media distribution is zero is generated on the upstream side. It is suggested that the larger the second region 60 is, the more the distribution of media is biased toward the downstream side, so that the first region 50 becomes larger.

  FIGS. 3A and 3B are media distributions that are conventionally desired, and the media are uniformly distributed in the cylinder. However, it is very difficult to stably obtain such a media distribution, and when the share is increased to uniformly distribute the media in this way, the metal oxide fine particles are likely to be altered. On the other hand, if the rotation speed of the stirring mill is decreased to reduce the collision speed between the media and the metal oxide fine particles in order to reduce the share, the rotation speed of the stirring mill decreases. , (B), the media distribution in the y-axis direction is biased, and the media tends to stay at the bottom. In this case, since the liquid to be treated passes through the upper part of the medium in which the liquid to be treated easily flows out of the cylinder by a short path, it becomes difficult to obtain a desired dispersion state, and the dispersion treatment takes a long time. According to the present invention, problems in such a conventional distributed processing method can be solved.

In the media distribution of the present embodiment, the capacity of the cylinder 3, the capacity of the first region 50 of the bead packing on the downstream side, and the bulk filling rate of the media 2 in the cylinder 3 are expressed by the following formula (3):
K / J ≧ 0.7P / 100 (3)
It is preferable to satisfy the condition represented by: Here, in formula (3), J represents the capacity (L) of the cylinder, K represents the capacity (L) of the first region, and P represents the bulk filling rate (%) of the medium in the cylinder.

  Here, the “bulk filling ratio of media in the cylinder” is the ratio of the capacity occupied by the media (including the gap between the media) out of the capacity of the cylinder when only the media is accommodated in the cylinder. That is. In such media distribution, a bead packing region is sufficiently formed in a substantially cylindrical hollow cylinder, and the metal oxide fine particles can be suitably dispersed.

Further, in the media distribution of the present embodiment, the capacity of the cylinder 3, the capacity of the second region 60 where the media distribution on the upstream side becomes zero, and the bulk filling rate of the media 2 in the cylinder 3 are expressed by the following equations. (4):
Q / J ≧ 0.7 {1- (P / 100)} (4)
It is preferable to satisfy the condition represented by: Here, in formula (4), J represents the capacity (L) of the cylinder, Q represents the capacity (L) of the second region, and P represents the bulk filling rate (%) of the medium in the cylinder.

  In such media distribution, the media is sufficiently unevenly distributed downstream in the cylinder, so that the first region 50 that is the bead packing can be made sufficiently large. Therefore, the metal oxide fine particle dispersion treatment can be more suitably performed.

  As a confirmation method of such a state, for example, a method of visually confirming using a transparent cylinder for testing can be mentioned. If it is difficult to confirm the medium, a colored medium may be produced and used.

(Electrophotographic photoreceptor and manufacturing method thereof)
FIG. 5 is a schematic cross-sectional view showing a preferred embodiment of the electrophotographic photosensitive member of the present invention. In the electrophotographic photoreceptor 10 shown in FIG. 5, an undercoat layer 14 is provided on a conductive substrate 12, and a charge generation layer 15, a charge transport layer 16, and a protective layer 17 are further provided on the undercoat layer 14. The photosensitive layer 13 is configured by laminating in this order.

  The conductive substrate 12 is formed by molding aluminum into a cylindrical shape (drum shape). As the substrate 12, a metal drum such as aluminum, copper, iron, stainless steel, zinc, or nickel can be used. In addition, on a substrate such as a sheet, paper, plastic or glass, a metal such as aluminum, copper, gold, silver, platinum, palladium, titanium, nickel-chromium, stainless steel, or indium, or a conductive material such as indium oxide or tin oxide. You may use what vapor-deposited a conductive metal compound. Further, a metal foil is laminated on the substrate, or conductive treatment is performed by dispersing and applying carbon black, indium oxide, tin oxide, antimony oxide powder, metal powder, copper iodide, etc. in a binder resin. Etc. can also be used. The shape of the substrate 12 is not limited to a drum shape, and may be a sheet shape or a plate shape. When the base 12 is made of a metal pipe, the surface may remain as it is, or a process such as mirror cutting, etching, anodizing, rough cutting, centerless grinding, sand blasting, wet honing is performed in advance. It may be.

  The undercoat layer 14 includes metal oxide fine particles and a binder resin that disperses the fine particles.

As the metal oxide fine particles, those having a powder resistance of about 10 ² to 10 ¹¹ Ω · cm, such as tin oxide, titanium oxide, and zinc oxide are preferably used. If the powder resistance is less than the lower limit, sufficient leakage preventing properties cannot be obtained, and if the powder resistance exceeds the upper limit, there is a concern that the residual potential is increased.

  These metal oxide fine particles may be used alone or in combination of two or more. The average particle diameter of the metal oxide fine particles is preferably 0.5 μm or less. The particle size here means an average primary particle size.

  In addition, as the metal oxide fine particles contained in the undercoat layer 14, those subjected to a surface treatment with a coupling agent can be used. The coupling agent is not particularly limited as long as it can obtain desired photoreceptor characteristics. Specifically, vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- ( 3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) ) -Γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloro Examples include silane coupling agents such as propyltrimethoxysilane It is. Moreover, these coupling agents can also be used in mixture of 2 or more types.

  As the surface treatment method, any known method can be used, but a dry method or a wet method is preferably used.

  When surface treatment is performed by a dry method, while stirring metal oxide fine particles with a mixer having a large shearing force, etc., a coupling agent dissolved directly or in an organic solvent or water is added dropwise together with dry air or nitrogen gas. It is uniformly processed by spraying. When adding or spraying the coupling agent, it is preferably performed at a temperature of 50 ° C. or higher. After adding or spraying the coupling agent, baking is preferably performed at 100 ° C. or higher. Baking can be carried out in an arbitrary range as long as the temperature and time allow the desired electrophotographic characteristics to be obtained. In the dry method, it is preferable to remove the surface adsorbed water by heating and drying the metal oxide fine particles before the surface treatment with the coupling agent. By removing the surface adsorbed water before the treatment, the coupling agent can be uniformly adsorbed on the surface of the metal oxide fine particles. The metal oxide fine particles can be heat-dried while stirring with a mixer having a large shearing force.

  As a wet method, the metal oxide fine particles are dispersed in a solvent using stirring, ultrasonic waves, a sand mill, an attritor, a ball mill, etc., and a coupling agent solution is added, stirred or dispersed, and then the solvent is removed to make it uniform To be processed. It is preferable to perform baking at 100 ° C. or higher after removing the solvent. Baking can be carried out in an arbitrary range as long as the temperature and time allow the desired electrophotographic characteristics to be obtained. Also in the wet method, it is preferable to remove the surface adsorbed water before the surface treatment of the metal oxide fine particles with the coupling agent. This surface adsorbed water removal method is implemented by a method of removing by heating and drying in a solvent used for surface treatment, a method of removing by azeotropy with a solvent, etc. in addition to removal by heating and drying as in the dry method. The

The amount of the surface treating agent relative to the metal oxide fine particles is appropriately selected so that desired electrophotographic characteristics can be obtained. The electrophotographic characteristics are influenced by the amount of coupling agent adhering to the metal oxide fine particles after the surface treatment, and the adhering amount is determined from the Si intensity in the fluorescent X-ray analysis and the main metal element intensity of the metal oxide. A preferable Si intensity in the fluorescent X-ray analysis is in the range of 1.0 × 10 ^{−5 to} 1.0 × 10 ⁻³ of the main metal element strength of the metal oxide. When the Si intensity is less than the lower limit, image quality defects such as fog are likely to occur, and when the upper limit is exceeded, defects such as an increase in residual potential are likely to occur.

  As the binder resin for the undercoat layer 14, acetal resin such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl Well-known polymer resin compounds such as acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol resin, phenol-formaldehyde resin, melamine resin, and urethane resin can be used. In addition, a charge transporting resin having a charge transporting group, a conductive resin such as polyaniline, or the like can be used. Among these, resins that are insoluble in the upper coating solvent are preferably used, and phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, epoxy resins, and the like are particularly preferably used.

  In the step of forming the undercoat layer 14, an undercoat layer coating liquid obtained by subjecting a liquid to be treated containing metal oxide fine particles and a binder resin to a dispersion treatment by the dispersion treatment method of the present invention is used. The ratio between the metal oxide fine particles and the binder resin in the coating solution for the undercoat layer can be arbitrarily set within a range in which desired electrophotographic photoreceptor characteristics can be obtained.

  Various additives can be used for the coating liquid for the undercoat layer in order to improve electrical characteristics, environmental stability, and image quality. Additives include quinone compounds such as chloranil, bromoanil and anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,5-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (4-naphthyl) -1,3,4-oxadiazole Oxadiazole compounds such as 2,5-bis (4-diethylaminophenyl) -1,3,4-oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5′-tetra-t -Electron transport materials such as diphenoquinone compounds such as butyl diphenoquinone, polycyclic condensation systems, azo-based electron transport pigments, zirconium chelate compounds, Data hexafluorophosphate chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, there can be used a known material such as a silane coupling agent.

  Such a silane coupling agent is used for surface treatment of metal oxides, but it can also be used as an additive added to a coating solution. Specific examples of the silane coupling agent used here include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ. -Glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β Examples include-(aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, and γ-chloropropyltrimethoxysilane.

  Such zirconium chelate compounds include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate. , Zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Such titanium chelate compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium. Examples thereof include salts, titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, and polyhydroxytitanium stearate.

  Examples of the aluminum chelate compound include aluminum isopropylate, monobutoxyaluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, and aluminum tris (ethyl acetoacetate).

  These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds.

  The solvent for the undercoat layer coating solution is arbitrarily selected from known organic solvents such as alcohols, aromatics, halogenated hydrocarbons, ketones, ketone alcohols, ethers and esters. be able to. More specifically, methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate, Usual organic solvents such as dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene can be used. These solvents can be used alone or in combination of two or more. When mixing, any solvent can be used as long as it can dissolve the binder resin as the mixed solvent.

  About the coating liquid for undercoat layers containing the said component, after carrying out a dispersion process by the dispersion processing method of this invention, the said coating liquid is apply | coated on the base | substrate 12, and the undercoat layer 14 is formed. As a coating method of the coating solution, a usual method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, a curtain coating method, or the like can be used.

  The thickness of the undercoat layer 14 formed in this way is preferably 15 μm or more, and more preferably 20 to 50 μm. Further, the Vickers strength of the undercoat layer 14 is preferably 35 or more.

  In order to prevent a moire image, the surface roughness of the undercoat layer 14 is preferably adjusted to ¼ n (n is the refractive index of the upper layer) to λ of the exposure laser wavelength λ used. Resin particles can be added to the undercoat layer for adjusting the surface roughness. As the resin particles, silicone resin particles, cross-linked PMMA resin particles, and the like can be used. In addition, the undercoat layer can be polished to adjust the surface roughness. As a polishing method, buffing, sand blasting, wet honing, grinding, or the like can be used.

  Further, an intermediate layer may be provided between the undercoat layer 14 and the photosensitive layer 13 in order to improve electrical characteristics, improve image quality, improve image quality maintainability, and improve photosensitive layer adhesion. The intermediate layer is acetal resin such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate. -In addition to polymer resin compounds such as maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, melamine resin, organometallic compounds containing zirconium, titanium, aluminum, manganese, silicon atoms, etc. is there. These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds. Among these, organometallic compounds containing zirconium or silicon are excellent in performance, such as low residual potential, little potential change due to environment, and little potential change due to repeated use.

  Such silicon-containing compounds include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxy. Silane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ -Aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane and the like. Among these, vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxy Silane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3- Silane coupling agents such as aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane are preferred.

  Such organic zirconium compounds include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate. , Zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Examples of the organic titanium compound include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, and titanium lactate ammonium. Examples thereof include salts, titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, and polyhydroxytitanium stearate.

  Examples of the organoaluminum compound include aluminum isopropylate, monobutoxyaluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, and aluminum tris (ethyl acetoacetate).

  In addition to improving the coatability of the upper layer, the intermediate layer also serves as an electrical blocking layer. However, when the film thickness is too large, the electrical barrier becomes too strong, causing desensitization and potential increase due to repetition. . Therefore, the film thickness when forming the intermediate layer is preferably 0.1 to 3 μm.

  The charge generation layer 15 is formed by forming a charge generation material by vacuum vapor deposition or by dispersing and applying it together with an organic solvent and a binder resin. When the charge generation layer is formed by dispersion coating, the charge generation layer is formed by dispersing the charge generation material in an organic solvent containing a binder resin, an additive, and the like and applying the obtained dispersion.

  Any known charge generating material can be used as the charge generating material. Examples of the charge generating material for infrared light include phthalocyanine pigments, squarylium, bisazo, trisazo, perylene, dithioketopyrrolopyrrole and the like. Examples of the charge generating material for visible light include condensed polycyclic pigments, bisazo, perylene, trigonal selenium, and dye-sensitized metal oxide fine particles. Among these, phthalocyanine pigments are particularly preferable because they have excellent performance. By using this, it is possible to obtain an electrophotographic photoreceptor having particularly high sensitivity and excellent repeatability. In addition, phthalocyanine pigments generally have several crystal forms, but any of these crystal forms can be used as long as it is a crystal form capable of obtaining a sensitivity suitable for the purpose. Particularly preferred phthalocyanine pigments include chlorogallium phthalocyanine, dichlorosus phthalocyanine, hydroxygallium phthalocyanine, metal-free phthalocyanine, oxytitanyl phthalocyanine, and chloroindium phthalocyanine.

  The phthalocyanine pigment crystals are produced by a known method. The phthalocyanine pigment is mechanically dry pulverized with an automatic mortar, planetary mill, vibration mill, CF mill, roller mill, sand mill, kneader, etc., or after dry pulverization, In addition, it can be produced by wet pulverization using a ball mill, mortar, sand mill, kneader or the like. Solvents used in the above treatment are aromatics (toluene, chlorobenzene, etc.), amides (dimethylformamide, N-methylpyrrolidone, etc.), aliphatic alcohols (methanol, ethanol, butanol, etc.), aliphatic polyvalents. Alcohols (ethylene glycol, glycerin, polyethylene glycol, etc.), aromatic alcohols (benzyl alcohol, phenethyl alcohol, etc.), esters (acetic ester, butyl acetate, etc.), ketones (acetone, methyl ethyl ketone, etc.), dimethyl sulfoxide, ether (Diethyl ether, tetrahydrofuran, etc.), several mixed systems, and mixed systems of water and these organic solvents. The usage-amount of a solvent is 1-200 weight part with respect to a pigment crystal, Preferably it is 10-100 weight part. The treatment temperature is −20 ° C. to the boiling point of the solvent, preferably −10 to 60 ° C.

  In addition, grinding aids such as sodium chloride and sodium nitrate can be used during grinding. The grinding aid may be used 0.5 to 20 times, preferably 1 to 10 times the weight of the pigment. Further, phthalocyanine pigment crystals produced by a known method can be controlled by combining acid pasting or acid pasting with dry grinding or wet grinding as described above. As an acid used for acid pasting, sulfuric acid is preferable, and one having a concentration of 70 to 100%, preferably 95 to 100% is used, and a dissolution temperature is in a range of -20 to 100 ° C, preferably -10 to 60 ° C. Set to The amount of concentrated sulfuric acid is set in the range of 1 to 100 times, preferably 3 to 50 times the weight of the phthalocyanine pigment crystals. As a solvent to be precipitated, water or a mixed solvent of water and an organic solvent is used in an arbitrary amount. The temperature for precipitation is not particularly limited, but it is preferably cooled with ice or the like in order to prevent heat generation.

  The binder resin used for the charge generation layer 15 can be selected from a wide range of insulating resins. It can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, and polysilane. Preferred binder resins include polyvinyl acetal resin, polyarylate resin (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin Insulating resins such as polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinyl pyrrolidone resin can be mentioned, but are not limited thereto. These binder resins can be used alone or in combination of two or more. Among these, a polyvinyl acetal resin is particularly preferably used.

  Further, the blending ratio (weight ratio) between the charge generating material and the binder resin is preferably in the range of 10: 1 to 1:10. The solvent for adjusting the coating solution may be arbitrarily selected from known organic solvents such as alcohols, aromatics, halogenated hydrocarbons, ketones, ketone alcohols, ethers and esters. it can. For example, methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, Usual organic solvents such as methylene chloride, chloroform, chlorobenzene, and toluene can be used. These solvents can be used alone or in combination of two or more. When mixing, any solvent can be used as long as it can dissolve the binder resin as a mixed solvent.

  As a dispersing method, methods such as a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker can be used. Furthermore, as a coating method used when providing this charge generation layer, a normal method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method is used. Can be used. In this dispersion, it is effective for high sensitivity and high stability that the particles have a particle size of 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less.

  Furthermore, the charge generation material can be subjected to a surface treatment in order to improve the stability of electrical characteristics and prevent image quality defects. A coupling agent or the like can be used as the surface treatment agent, but is not limited thereto. Examples of coupling agents used for the surface treatment include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycol. Sidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- ( Examples include silane coupling agents such as aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, and γ-chloropropyltrimethoxysilane. Among these, silane coupling agents particularly preferably used include vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- ( 3,4-epoxycyclohexyl) ethyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-aminopropyl Examples include silane coupling agents such as triethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane.

  In addition, an organometallic compound of zirconium, titanium, or aluminum can be used as a coupling agent used for the surface treatment. Specific examples of the organic zirconium compound include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl zirconium acetoacetate, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, and octane. Zirconate, zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like. Moreover, as an organic titanium compound, tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium Examples thereof include salts, titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, and polyhydroxytitanium stearate. Furthermore, examples of the organoaluminum compound include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, and aluminum tris (ethyl acetoacetate).

  Furthermore, various additives can be added to the coating solution for charge generation layer in order to improve electrical characteristics and image quality. Additives include quinone compounds such as chloranil, bromoanil and anthraquinone, tetracyanoquinodimethane compounds, fluorenones such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone Compound, 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (4-naphthyl) -1,3,4-oxadi Azoles, oxadiazole compounds such as 2,5-bis (4-diethylaminophenyl) -1,3,4-oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5′-tetra- Electron transport materials such as diphenoquinone compounds such as t-butyldiphenoquinone, electron transport pigments such as polycyclic condensation systems and azo systems, zirconium chelate compounds Titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, there can be used a known material such as a silane coupling agent.

  Such silane coupling agents include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltri Methoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl)- Examples include γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, and γ-chloropropyltrimethoxysilane.

  Such zirconium chelate compounds include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate. , Zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Such titanium chelate compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium. Examples thereof include salts, titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, and polyhydroxytitanium stearate.

  Examples of the aluminum chelate compound include aluminum isopropylate, monobutoxyaluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, and aluminum tris (ethyl acetoacetate).

  These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds.

  As a coating method in the formation process of the charge generation layer 15, a normal method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method should be used. Can do.

  The charge transport layer 16 includes a charge transport material. As the charge transporting material, any known materials can be used. Specifically, oxadiazoles such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole can be used. Derivatives, pyrazoline derivatives such as 1,3,5-triphenyl-pyrazoline, 1- [pyridyl- (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline, triphenylamine, Tri (p-methyl) phenylamine, N, N′-bis (3,4-dimethylphenyl) biphenyl-4-amine, dibenzylaniline, 9,9-dimethyl-N, N′-di (p-tolyl) Aromatic tertiary amino compounds such as fluorenone-2-amine, N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1-bif Nyl] -4,4′-diamine and other aromatic tertiary diamino compounds, 3- (4′-dimethylaminophenyl) -5,6-di- (4′-methoxyphenyl) -1,2,4- 1,2,4-triazine derivatives such as triazine, 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, 4-diphenylaminobenzaldehyde-1,1-diphenylhydrazone, [p- (diethylamino) phenyl] (1-naphthyl) Hydrazone derivatives such as phenylhydrazone, quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline, benzofuran derivatives such as 6-hydroxy-2,3-di (p-methoxyphenyl) -benzofuran, p- (2,2- Diphenylvinyl) -N. Α-stilbene derivatives such as N′-diphenylaniline, enamine derivatives, carbazole derivatives such as N-ethylcarbazole, hole transport materials such as poly-N-vinylcarbazole and derivatives thereof, and quinone compounds such as chloranil, bromoanil and anthraquinone , Fluorenone compounds such as tetracyanoquinodimethane compounds, 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2- (4-biphenyl) -5- (4- t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (4-naphthyl) -1,3,4-oxadiazole, 2,5-bis (4-diethylaminophenyl) -1 Oxadiazole compounds such as 1,3,4-oxadiazole, xanthone compounds, thiophene compounds Examples include electron transport materials such as diphenoquinone compounds such as 3,3 ′, 5,5′-tetra-t-butyldiphenoquinone, or polymers having groups consisting of the compounds shown above in the main chain or side chain. It is done. These charge transport materials can be used alone or in combination of two or more.

  As the binder resin for the charge transport layer 16, any known resin can be used, but an electric insulating film-forming resin is preferable. For example, polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, vinyl chloride-acetic acid Vinyl copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-carbazole, polyvinyl butyral, polyvinyl formal, polysulfone , Casein, gelatin, polyvinyl alcohol, ethyl cellulose, phenol resin, polyamide, carboxy-methyl cellulose, vinylidene chloride polymer wax, polyureta However, it is not limited to these. These binder resins can be used singly or in combination of two or more, and in particular, polycarbonate resins, polyester resins, methacrylic resins, and acrylic resins are compatible with charge transport materials, and are compatible with solvents. It is excellent and preferably used in terms of solubility and strength. The blending ratio (weight ratio) between the binder resin and the charge transport material can be arbitrarily set in any case, but attention must be paid to a decrease in electrical characteristics and a decrease in film strength.

  As a coating method in the formation process of the charge transport layer, a usual method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method may be used. it can. As a solvent used for the coating solution, a common organic solvent such as dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, toluene and the like can be used alone or in admixture of two or more.

  The film thickness of the charge transport layer 16 thus obtained is preferably 5 to 50 μm, more preferably 10 to 40 μm.

  In addition, for the purpose of preventing deterioration of the photoconductor due to ozone, oxidizing gas, or light / heat generated in the electrophotographic apparatus, an anti-oxidant and a light stabilizer are added to the electrophotographic photoconductor. An agent can be added.

  For example, examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and derivatives thereof, organic sulfur compounds, and organic phosphorus compounds.

  Such phenolic antioxidants include 2,6-di-t-butyl-4-methylphenol, styrenated phenol, n-octadecyl-3- (3 ′, 5′-di-t-butyl-4′- Hydroxyphenyl) -propionate, 2,2'-methylene-bis (4-methyl-6-t-butylphenol), 2-t-butyl-6- (3'-t-butyl-5'-methyl-2'- Hydroxybenzyl) -4-methylphenyl acrylate, 4,4′-butylidene-bis (3-methyl-6-tert-butyl-phenol), 4,4′-thiobis- (3-methyl-6-tert-butylphenol) 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl- 4'-hydroxyphenyl) propionate] methane, 3.9-bis [2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl] -2 4,8,10-tetraoxaspiro [5,5] undecane and the like.

  Examples of the hindered amine antioxidant include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2- [3- (3,5-Di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionyloxy] -2,2,6,6-tetramethylpiperidine, 8-benzyl-7,7,9, -tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2 , 4-dione, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetosuccinate Methylpiperidine polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diimyl} {(2,2,6,6- Tetramethyl-4-piperidyl) imino} hexamethylene {(2,3,6,6-tetramethyl-4-piperidyl) imino}], 2- (3,5-di-t-butyl-4-hydroxybenzyl) 2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl -N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino [-6-chloro-1,3,5-triazine condensate and the like.

  Examples of the organic sulfur-based antioxidant include dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, penta Examples include erythritol-tetrakis- (β-laurylthiopropionate), ditridecyl-3,3′-thiodipropionate, and 2-mercaptobenzimidazole.

  Examples of such organic phosphorus-based antioxidants include trisnonylphenyl phosphite, triphenyl phosfeft, and tris (2,4-di-t-butylphenyl) -phosfte.

  Organic sulfur-based and organic phosphorus-based antioxidants are used as secondary antioxidants, and a synergistic effect can be obtained by using them together with primary antioxidants such as phenol-based or amine-based antioxidants.

  Examples of the light stabilizer include benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine derivatives.

  Examples of such benzophenone light stabilizers include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, and 2,2'-di-hydroxy-4-methoxybenzophenone.

  Examples of the benzotriazole-based light stabilizer include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- [2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ″, 6 "-tetrahydrophthalimidomethyl) -5'-methylphenyl] -benzotriazole, 2- (2'-hydroxy-3'-t-but-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2 '-Hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3', 5'-t-butylphenyl) benzotriazole, 2- (2 '-Hydroxy-5'-t-octylphenyl) benzotriazole, 2- (2'-hydroxy-3', 5'-di-t-amylphenyl) benzotriazole Etc., and the like. Examples of other compounds include 2,4-di-t-butylphenyl-3 ', 5'-di-t-butyl-4'-hydroxybenzoate and nickel dibutyl-dithiocarbamate.

Further, at least one kind of electron accepting substance can be included for the purpose of improving sensitivity, reducing residual potential, reducing fatigue during repeated use, and the like. Examples of the electron accepting substance that can be used in the photoreceptor of the present invention include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o -Dinitrobenzene, m-dinitrobenzene, chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, phthalic acid and the like can be mentioned. Of these, fluorenone-based, quinone-based, and benzene derivatives having electron-withdrawing substituents such as Cl, CN, NO ₂ are particularly preferable. Further, the charge transport layer 16 may contain fine particles such as silica and PTFE. A small amount of silicone oil can also be added to the coating solution as a leveling agent for improving the smoothness of the coating film.

  In the electrophotographic photosensitive member of the present invention, as shown in FIG. 5, a protective layer 17 can be provided as necessary. This protective layer is used in a photoreceptor having a laminated structure to prevent chemical change of the charge transport layer during charging or to further improve the mechanical strength of the photosensitive layer. The protective layer includes a curable resin, a siloxane resin cured film containing a charge transporting compound, a film formed by containing a conductive material in a suitable binder resin, and the like. Any curable resin can be used as long as it is a public resin. Examples thereof include phenol resin, polyurethane resin, melamine resin, diallyl phthalate resin, and siloxane resin. In the case of a cured siloxane resin film containing a charge transporting compound, any known material can be used as the charge transporting compound. For example, JP-A-10-95787, JP-A-10-251277, Examples thereof include, but are not limited to, compounds disclosed in JP-A-11-32716, JP-A-11-38656, and JP-A-11-236391.

  When the protective layer 17 is a film formed by containing a conductive material in an appropriate binder resin, examples of the conductive material include metallocene compounds such as N, N′-dimethylferrocene, N, N′-diphenyl, and the like. Aromatic amine compounds such as N, N′-bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine, molybdenum oxide, tungsten oxide, antimony oxide, tin oxide, titanium oxide, Indium oxide, tin oxide and antimony or antimony oxide solid solution carrier or a mixture thereof, or a mixture of these metal oxide fine particles in a single particle, or a coated one, but is not limited thereto. It is not something.

  The binder resin used for the protective layer 17 is polyamide resin, polyvinyl acetal resin, polyurethane resin, polyester resin, epoxy resin, polyketone resin, polycarbonate resin, polyvinyl ketone resin, polystyrene resin, polyacrylamide resin, polyimide resin, polyamideimide resin. Known resins such as these can be used, and these can be used after being crosslinked.

  The protective layer 17 can contain an antioxidant. Examples of such antioxidants include phenolic antioxidants, hindered amine antioxidants, and organic phosphorus antioxidants.

  Specifically, as the phenolic antioxidant, 2,6-di-t-butyl-4-methylphenol, styrenated phenol, n-octadecyl-3- (3 ′, 5′-di-t-butyl- 4'-hydroxyphenyl) -propionate, 2,2'-methylene-bis (4-methyl-6-t-butylphenol), 2-t-butyl-6- (3'-t-butyl-5'-methyl- 2'-hydroxybenzyl) -4-methylphenyl acrylate, 4,4'-butylidene-bis (3-methyl-6-tert-butyl-phenol), 4,4'-thiobis- (3-methyl-6-t -Butylphenol), 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, tetrakis- [methylene-3- (3 ', 5'-di-t- Spotted -4'-hydroxyphenyl) propionate] methane, 3.9-bis [2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane and the like.

  Examples of the hindered amine antioxidant include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2- [3- (3,5-Di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionyloxy] -2,2,6,6-tetramethylpiperidine, 8-benzyl-7,7,9, -tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2 , 4-dione, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetosuccinate Methylpiperidine polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diimyl} {(2,2,6,6- Tetramethyl-4-piperidyl) imino} hexamethylene {(2,3,6,6-tetramethyl-4-piperidyl) imino}], 2- (3,5-di-t-butyl-4-hydroxybenzyl) 2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl -N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino [-6-chloro-1,3,5-triazine condensate and the like.

  In addition, examples of such organic phosphorus antioxidants include known antioxidants such as trisnonylphenyl phosphite, triphenyl phosfeft, and tris (2,4-di-t-butylphenyl) phosphite, and siloxane resins. And an antioxidant having a functional group such as a hydroxyl group, an amino group, and an alkoxysilyl group that can be bonded to the hydroxyl group. Furthermore, the protective layer may contain fine particles such as silica and PTFE.

  As a coating method in the forming process of the protective layer 17, it is possible to use a usual method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method. it can. As a solvent used for coating, ordinary organic solvents such as dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene can be used singly or as a mixture of two or more kinds, but a solvent in which the lower layer is hardly dissolved is used as much as possible. It is preferable.

  The film thickness of the protective layer 17 thus obtained is preferably 1 to 20 μm, more preferably 1 to 10 μm.

  In the electrophotographic photoreceptor of the present invention, the film thickness of the functional layer above the charge generation layer for obtaining high resolution is preferably 50 μm or less, preferably 40 μm or less. When the functional layer is a thin film, the combination of the particle-dispersed undercoat layer of the present invention and a high-strength protective layer is particularly effectively used.

  In the electrophotographic photosensitive member shown in FIG. 5, an undercoat layer 14, a charge generation layer 15, a charge transport layer 16, and a protective layer 17 are laminated in this order on a conductive substrate 12. The configuration of the electrophotographic photosensitive member is not limited to this. For example, when the charge transport layer 16 has sufficient strength, the protective layer 17 may not be provided. Further, the stacking order of the charge generation layer 15 and the charge transport layer 16 may be reversed. Further, the electrophotographic photosensitive member shown in FIG. 5 is a function-separated type photosensitive member in which the charge generation layer 15 and the charge transport layer 16 are separately provided. The photosensitive layer includes both the charge generation material and the charge transport material. (Single layer type photosensitive layer) may be provided.

The electrophotographic photosensitive member of the present invention is suitably used in electrophotographic apparatuses such as laser beam printers, digital copying machines, LED printers, and laser facsimiles that emit near-infrared light or visible light. The laser beam is preferably a laser that oscillates light of 350 to 800 nm in order to obtain a high-definition image. Further, the laser beam preferably has a spot diameter of 10 ⁴ μm ² or less, more preferably 3 × 10 ³ μm ² or less in order to obtain a high-definition image.

(Electrophotographic equipment)
FIG. 6 is a cross-sectional view schematically showing a basic configuration of a preferred embodiment of the electrophotographic apparatus of the present invention. An image forming apparatus 200 as an electrophotographic apparatus shown in FIG. 6 includes an electrophotographic photosensitive member 207 of the present invention, a charging device 208 that charges the electrophotographic photosensitive member 207 by a contact charging method, and a power source connected to the charging device 208. 209, an exposure device 210 that exposes the electrophotographic photosensitive member 207 charged by the charging device 208 to form an electrostatic latent image, and a toner image obtained by developing the electrostatic latent image formed by the exposure device 210 with toner. , A transfer device 212 that transfers a toner image formed by the development device 211 to the transfer target 500, a cleaning device 213, a static eliminator 214, and a fixing device 215. In this case, the static eliminator 214 may not be provided.

  The charging device 208 shown in FIG. 6 contacts a contact-type charging member (for example, a charging roll) with the surface of the photoconductor 207 to uniformly apply a voltage to the photoconductor to charge the surface of the photoconductor to a predetermined potential. Is.

  As the contact-type charging member, a roller-shaped member in which an elastic layer, a resistance layer, a protective layer and the like are provided on the outer peripheral surface of the core material is preferably used. The shape of the contact-type charging member may be any of the above-described roller shape, brush shape, blade shape, pin electrode shape, film shape, etc., and may be arbitrarily selected according to the specifications and form of the image forming apparatus. it can.

  As a material of the core material in the roller-shaped contact type charging member, a conductive material such as iron, copper, brass, stainless steel, aluminum, nickel or the like is used. Also, a resin molded product in which conductive particles or the like are dispersed can be used.

As the material of the elastic layer on the outer peripheral surface of the core material, a material having conductivity or semiconductivity, for example, a material in which conductive particles or semiconducting particles are dispersed in a rubber material can be used. EPDM, polybutadiene, natural rubber, polyisobutylene, SBR, CR, NBR, silicone rubber, urethane rubber, epichlorohydrin rubber, SBS, thermoplastic elastomer, norbornene rubber, fluorosilicone rubber, ethylene oxide rubber, chloroprene rubber, isoprene Rubber, epoxy rubber or the like is used. Examples of conductive particles or semiconductive particles include carbon black, zinc, aluminum, copper, iron, nickel, chromium, titanium, and other metals, ZnO—Al ₂ O ₃ , SnO ₂ —Sb ₂ O ₃ , In ₂ O _3. Metal oxides such as —SnO ₂ , ZnO—TiO ₂ , MgO—Al ₂ O ₃ , FeO—TiO ₂ , TiO ₂ , SnO ₂ , Sb ₂ O ₃ , In ₂ O ₃ , ZnO, and MgO can be used. . These materials can be used individually by 1 type or in mixture of 2 or more types.

  Moreover, as a material of the resistance layer and the protective layer on the outer peripheral surface of the core material, a material in which conductive particles or semiconductive particles are dispersed in a binder resin and the resistance thereof is controlled is used. Examples of the binder resin include acrylic resin, cellulose resin, polyamide resin, methoxymethylated nylon, ethoxymethylated nylon, polyurethane resin, polycarbonate resin, polyester resin, polyethylene resin, polyvinyl resin, polyarylate resin, polythiophene resin, PFA, A polyolefin resin such as FEP or PET, a styrene butadiene resin, or the like is used. In addition, as the conductive particles or semiconductive particles dispersed in the binder resin, the same carbon black, metal, and metal oxide as the elastic layer are used. Moreover, antioxidants, such as hindered phenol and hindered amine, fillers, such as clay and kaolin, lubricants, such as silicone oil, etc. can be added as needed. As a means for forming these layers, a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, a curtain coating method, a melt molding method, an injection molding method, or the like is used. be able to.

  When charging the photoreceptor using these contact-type charging members, a voltage is applied to the contact-type charging member. The applied voltage may be either a DC voltage or a DC voltage superimposed with an AC voltage.

  Instead of the contact-type charging member in FIG. 6, a non-contact type corona charging device such as a corotron or a scorotron can be used. These can be arbitrarily selected according to the specifications and form of the image forming apparatus.

  As the exposure apparatus 210, an optical system apparatus that can expose a light source such as a semiconductor laser, an LED (light emitting diode), and a liquid crystal shutter on the surface of the electrophotographic photosensitive member in a desired image-like manner can be used.

  As the developing device 211, a conventionally known developing device using a regular or reversal developer such as a one-component system or a two-component system can be used.

The shape of the toner used in the developing device 211 is not particularly limited, but a spherical toner is preferable from the viewpoint of high image quality and ecology. The spherical toner is a toner having a spherical shape having an average shape factor (ML ² / A) of 100 to 130, preferably 100 to 125, in order to achieve high transfer efficiency. When this average shape factor (ML ² / A) is larger than 130, the transfer efficiency is lowered, and the deterioration of the image quality of the print sample can be visually confirmed.

Here, the average shape factor (ML ² / A) is an average value of the shape factors obtained for the toner particles. The average shape factor of each toner particle is calculated from the maximum length and area by measuring the equivalent circle diameter by taking an image obtained by observing the toner with an optical microscope into an image analyzer (for example, LUZEX III, manufactured by Nireco). (5):
(ML ² / A) = (maximum length) ² × π × 100 / [4 × (area)] (5)
Can be determined according to In the case of a true sphere, ML ² / A = 100.

  The spherical toner contains at least a binder resin and a colorant. The spherical toner may preferably use particles having a size of 10 μm or less, more preferably particles having a size of 8 μm or less.

  Examples of the binder resin include homopolymers and copolymers such as styrenes, monoolefins, vinyl esters, α-methylene aliphatic monocarboxylic acid esters, vinyl ethers, vinyl ketones, Particularly typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. A polymer, polyethylene, polypropylene, etc. are mentioned. Furthermore, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax, and the like can also be mentioned.

  Examples of such colorants include magnetic powders such as magnetite and ferrite, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, and malachite green oxalate. , Lamp Black, Rose Bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 is a typical example.

  The spherical toner may be internally added or externally added with a known additive such as a release agent, a charge control agent, and other inorganic fine particles.

  Typical examples of the releasing agent include low molecular polyethylene, low molecular polypropylene, Fischer-Tropsch wax, montan wax, carnauba wax, rice wax, and candelilla wax.

  As such a charge control agent, a known one can be used, but an azo metal complex compound, a metal complex compound of salicylic acid, a resin type charge control agent containing a polar group, or the like can be used.

  In addition, as other inorganic fine particles, small-diameter inorganic fine particles having an average primary particle size of 40 nm or less are used for the purpose of powder flowability, charge control, etc. Large-diameter inorganic or organic fine particles may be used in combination. As these other inorganic fine particles, known ones can be used. In particular, the surface treatment of the small-diameter inorganic fine particles is effective because the dispersibility becomes high and the effect of increasing the powder fluidity increases.

  In addition, a surface lubricant (metal fatty acid salt) and fine particles having an abrasive effect can be added to the spherical toner.

  The spherical toner is not particularly limited by the production method, and can be obtained by a known method. Specifically, for example, a kneading and pulverizing method, a method of changing the shape of particles obtained by the kneading and pulverizing method with mechanical impact force or thermal energy, an emulsion polymerization aggregation method, a dissolution suspension method and the like can be mentioned. In addition, a manufacturing method may be performed in which the spherical toner obtained by the above method is used as a core, and aggregated particles are further adhered and heat-fused to give a core-shell structure. When the external additive is added, it can be produced by mixing the spherical toner and the external additive with a Henschel mixer or a V blender. In addition, when the spherical toner is manufactured by a wet method, it can be externally added by a wet method.

  Examples of the transfer device 212 include a roller-type contact charging member, a contact-type transfer charger using a belt, a film, a rubber blade, or the like, a scorotron transfer charger using a corona discharge, a corotron transfer charger, or the like. .

  The cleaning device 213 is for removing residual toner adhering to the surface of the electrophotographic photosensitive member after the transfer process. The cleaned electrophotographic photosensitive member is repeatedly used for the image forming process described above. . As the cleaning device, brush cleaning, roll cleaning, and the like can be used in addition to the cleaning blade. Among these, it is preferable to use the cleaning blade. Examples of the material for the cleaning blade include urethane rubber, neoprene rubber, and silicone rubber.

  The electrophotographic apparatus of the present invention may further include an erase light irradiation device 214 as shown in FIG. As a result, when the electrophotographic photosensitive member is repeatedly used, the phenomenon that the residual potential of the electrophotographic photosensitive member is brought into the next cycle is prevented, so that the image quality can be further improved.

  FIG. 7 is a cross-sectional view schematically showing a basic configuration of another embodiment of the electrophotographic apparatus of the present invention. An image forming apparatus 220 shown in FIG. 7 is an electrophotographic apparatus of an intermediate transfer type. In the housing 400, four electrophotographic photoreceptors 401a to 401d (for example, the electrophotographic photoreceptor 401a is yellow and the electrophotographic photoreceptor 401b is magenta. The electrophotographic photosensitive member 401c can form an image of cyan and the electrophotographic photosensitive member 401d can form a black color) are arranged in parallel along the intermediate transfer belt 409.

  Here, the electrophotographic photoreceptors 401a to 401d mounted on the image forming apparatus 220 are the electrophotographic photoreceptors of the present invention.

  Each of the electrophotographic photosensitive members 401a to 401d can be rotated in a predetermined direction (counterclockwise on the paper surface), and the charging rolls 402a to 402d, the developing devices 404a to 404d, and the primary transfer roll 410a along the rotation direction. To 410d and cleaning blades 415a to 415d are arranged. Each of the developing devices 404a to 404d can be supplied with toners of four colors, black, yellow, magenta, and cyan accommodated in toner cartridges 405a to 405d, and the primary transfer rolls 410a to 410d are respectively intermediate transfer belts. 409 is in contact with the electrophotographic photoreceptors 401a to 401d.

  Further, a laser light source (exposure device) 403 is disposed at a predetermined position in the housing 400, and the surface of the electrophotographic photoreceptors 401a to 401d after charging is irradiated with laser light emitted from the laser light source 403. Is possible. Accordingly, charging, exposure, development, primary transfer, and cleaning are sequentially performed in the rotation process of the electrophotographic photosensitive members 401a to 401d, and the toner images of the respective colors are transferred onto the intermediate transfer belt 409 in an overlapping manner.

  The intermediate transfer belt 409 is supported with a predetermined tension by a drive roll 406, a backup roll 408, and a tension roll 407, and can rotate without causing deflection due to the rotation of these rolls. Further, the secondary transfer roll 413 is disposed so as to contact the backup roll 408 via the intermediate transfer belt 409. The intermediate transfer belt 409 passing between the backup roll 408 and the secondary transfer roll 413 is cleaned by, for example, a cleaning blade 416 disposed in the vicinity of the drive roll 406 and then repeatedly used for the next image forming process. Is done.

  A tray (transfer object tray) 411 is provided at a predetermined position in the housing 400, and the transfer object 4, such as paper in the tray 411, is transferred to the intermediate transfer belt 409 and the secondary transfer roll by the transfer roll 412. Then, the paper is sequentially transferred between the two fixing rolls 414 that are in contact with each other and the two fixing rolls 414, and then discharged to the outside of the housing 400.

  In the above description, the case where the intermediate transfer belt 409 is used as the intermediate transfer member has been described. However, the intermediate transfer member may have a belt shape like the intermediate transfer belt 409 or a drum shape. Also good. In the case of a belt shape, a conventionally known resin can be used as the resin material used as the base material of the intermediate transfer member. For example, polyimide resin, polycarbonate resin (PC), polyvinylidene fluoride (PVDF), polyalkylene terephthalate (PAT), ethylenetetrafluoroethylene copolymer (ETFE) / PC, ETFE / PAT, PC / PAT blend material, polyester Resin materials such as polyether ether ketone and polyamide, and resin materials using these as main raw materials. Furthermore, a resin material and an elastic material can be blended and used.

  As the elastic material, polyurethane, chlorinated polyisoprene, NBR, chloropyrene rubber, EPDM, hydrogenated polybutadiene, butyl rubber, silicone rubber, or the like can be used, or a material obtained by blending two or more kinds can be used. If necessary, a conductive agent imparting electronic conductivity or a conductive agent having ionic conductivity is added to the resin material and the elastic material used for these base materials, or a combination of two or more types. Among these, it is preferable to use a polyimide resin in which a conductive agent is dispersed from the viewpoint of excellent mechanical strength. As the conductive agent, a conductive polymer such as carbon black, metal oxide, or polyaniline can be used.

  When a belt-shaped configuration such as the intermediate transfer belt 409 is employed as the intermediate transfer member, the thickness of the belt is generally preferably 50 to 500 μm and more preferably 60 to 150 μm, but is appropriately selected according to the hardness of the material. be able to.

  For example, a belt made of a polyimide resin in which a conductive agent is dispersed is 5 to 20% by weight as a conductive agent in a polyamic acid solution as a polyimide precursor, as described in JP-A-63-111263. After the carbon black is dispersed, the dispersion is cast on a metal drum and dried, and then the film peeled off from the drum is stretched at a high temperature to form a polyimide film. Can be produced.

  The film molding is generally performed by injecting a polyamic acid solution film-forming stock solution in which a conductive agent is dispersed into a cylindrical mold and, for example, heating at 100 to 200 ° C. at a rotational speed of 500 to 2000 rpm. The film was formed into a film by a centrifugal molding method while rotating, and then the obtained film was demolded in a semi-cured state and covered with an iron core. It can be carried out by proceeding a ring-closing reaction) and carrying out main curing. In addition, the stock solution is cast on a metal sheet to a uniform thickness and heated to 100 to 200 ° C. to remove most of the solvent in the same manner as described above, and then gradually raised to a high temperature of 300 ° C. or higher. There is also a method of forming a polyimide film. The intermediate transfer member may have a surface layer.

  When a drum-shaped configuration is adopted as the intermediate transfer member, it is preferable to use a cylindrical substrate formed of aluminum, stainless steel (SUS), copper, or the like as the substrate. If necessary, an elastic layer can be coated on the cylindrical substrate, and a surface layer can be formed on the elastic layer.

  The transfer target in the present invention is not particularly limited as long as it is a medium to which a toner image formed in the shape of an electrophotographic photosensitive member is transferred. For example, when transferring directly from an electrophotographic photosensitive member to paper or the like, paper or the like is a transfer target, and when an intermediate transfer member is used, the intermediate transfer member is a transfer target.

(Process cartridge)
FIG. 8 is a cross-sectional view schematically showing a basic configuration of a preferred embodiment of a process cartridge including the electrophotographic photosensitive member of the present invention. In addition to the electrophotographic photosensitive member 207, the process cartridge 300 is provided with a charging device 208, a developing device 211, a cleaning device (cleaning means) 213, an opening 218 for exposure, and an opening 217 for static elimination exposure. Are combined and integrated with each other.

  The process cartridge 300 is detachably attached to an image forming apparatus main body including a transfer device 212, a fixing device 215, and other components (not shown), and the image forming apparatus together with the image forming apparatus main body. It constitutes.

  In the image forming apparatus and the process cartridge described above, a high level of image quality can be obtained by using the electrophotographic photosensitive member of the present invention that is excellent in electrical characteristics and leak prevention.

  Hereinafter, although an example and a comparative example explain the present invention still in detail, the present invention is not limited to these examples and a comparative example.

[Example 1]
100 parts by weight of zinc oxide (average particle size: 70 nm, prototype product manufactured by Teika) is stirred and mixed with 500 parts by weight of toluene, and 1.5 parts by weight of a silane coupling agent (trade name: KBM603, manufactured by Shin-Etsu Chemical Co., Ltd.) is added. And stirred for 2 hours. Thereafter, toluene was distilled off under reduced pressure, and baking was performed at 150 ° C. for 2 hours. As a result of analyzing the obtained surface-treated zinc oxide by fluorescent X-ray, the ratio of the Si element intensity to the Zn element intensity (Si / Zn) was 1.5 × 10 ⁻⁴ .

  60 parts by weight of zinc oxide thus surface-treated, 15 parts by weight of a curing agent (blocked isocyanate, trade name: Sumidur BL3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.) and butyral resin (trade name: BM-1, Sekisui) A liquid to be treated was obtained by mixing 25 parts by weight of methyl ethyl ketone with 38 parts by weight of a solution obtained by dissolving 15 parts by weight of Chemical Co., Ltd. in 85 parts by weight of methyl ethyl ketone. The liquid viscosity of this liquid to be treated was about 200 mPa · s.

Next, the dispersion | distribution process was performed in the following procedures using the horizontal type | mold media mill disperser (KDL-PILOT type | mold, a dyno mill, the Shinmaru Enterprises company make). First, a dispersing machine having the configuration shown in FIG. 1 was used. The cylinder and the stirring mill of the disperser are made of ceramics mainly composed of zirconia. The length of the cylinder in the central axis direction is 214 mm, and the inner diameter of the cylinder is 100 mm (L / D = 2.14). 1mmφ glass beads (Hi-D20, manufactured by OHARA INC.) Are charged into this cylinder at a bulk filling rate of 80%, the peripheral speed of the stirring mill is 8 m / min, and the flow rate of the liquid to be treated is 1000 mL / min. (D ² L / 1273V = 1.68 (rounded to three decimal places)). A magnet gear pump was used for feeding the liquid to be treated.

  In the dispersion treatment, a part of the liquid to be treated was sampled after a predetermined time, and the transmittance during film formation was measured. That is, the liquid to be treated was applied on a glass plate so as to have a film thickness of 20 μm, and after curing at 150 ° C. for 2 hours to form a coating film, a spectrophotometer (U-2000, manufactured by Hitachi, Ltd.) ) Was used to determine the transmittance at a wavelength of 950 nm. The dispersion process was terminated when the transmittance (value with respect to a film thickness of 20 nm) exceeded 70%.

  To the dispersion thus obtained, 0.005 part by weight of dioctyltin dilaurate and 0.01 part by weight of silicone oil (trade name: SH29PA, manufactured by Toray Dow Corning Silicone Co., Ltd.) are added as a catalyst. A coating solution was prepared. This coating solution was applied on an aluminum substrate having a diameter of 30 mm, a length of 340 mm, and a thickness of 1 mm by a dip coating method, followed by drying and curing at 160 ° C. for 100 minutes to form an undercoat layer having a thickness of 20 μm. In this step, the amount of impurities contained in the coating solution was analyzed using a fluorescent X-ray analyzer (3370E, manufactured by Rigaku Denki), and it was confirmed whether or not the contamination of the impurities in the coating solution was sufficiently suppressed. Further, the color of the coating solution was visually observed to confirm the presence or absence of a color change. Table 1 shows the evaluation of the present example and the following examples and comparative examples.

  Next, a photosensitive layer was formed on the undercoat layer. First, the position of Bragg angles (2θ ± 0.2 °) of X-ray diffraction spectrum using CuKα ray as a charge generating material is at least 7.4 °, 16.6 °, 25.5 °, 28.3 °. 15 parts by weight of gallium chloride phthalocyanine having a diffraction peak, 10 parts by weight of vinyl chloride-vinyl acetate copolymer resin (trade name: VMCH, manufactured by Nihon Unicar) as a binder resin, and 300 parts by weight of n-butyl alcohol The mixture was dispersed in a sand mill for 4 hours using 1 mmφ glass beads to obtain a coating solution for charge generation layer. The obtained dispersion was dip coated on the undercoat layer and dried to form a charge generation layer having a thickness of 0.2 μm.

  Furthermore, 4 parts by weight of N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1 ′] biphenyl-4,4′-diamine and bisphenol Z polycarbonate resin (viscosity average molecular weight: 40,000) 6 parts by weight was added to 80 parts by weight of chlorobenzene and dissolved to obtain a coating solution for a charge transport layer. This coating solution was applied onto the charge generation layer and dried at 130 ° C. for 40 minutes to form a charge transport layer having a thickness of 25 μm. Thus, an electrophotographic photoreceptor of Example 1 was obtained.

[Example 2]
Example except that the viscosity of the liquid to be treated is adjusted to 10 mPa · s by adjusting the mixing amount of methyl ethyl ketone as a component of the liquid to be treated, and the flow rate of the liquid to be treated in the cylinder is 800 mL / min in the dispersion treatment of the liquid to be treated. In the same manner as in Example 1, an electrophotographic photoreceptor of Example 2 was obtained.

[Example 3]
Example: The viscosity of the liquid to be treated is adjusted to 10 mPa · s by adjusting the mixing amount of methyl ethyl ketone as the liquid component to be treated, and the flow rate of the liquid to be treated in the cylinder is 3000 mL / min in the dispersion treatment of the liquid to be treated. In the same manner as in Example 1, an electrophotographic photoreceptor of Example 3 was obtained.

[Example 4]
An electrophotographic photosensitive member of Example 4 was obtained in the same manner as in Example 1 except that the mixing amount of methyl ethyl ketone as the liquid component to be processed was adjusted so that the viscosity of the liquid to be processed was 500 mPa · s.

[Comparative Example 1]
Example except that the viscosity of the liquid to be treated is adjusted to 4 mPa · s by adjusting the amount of methyl ethyl ketone as the liquid component to be treated, and the flow rate of the liquid to be treated in the cylinder is 800 mL / min in the dispersion treatment of the liquid to be treated. In the same manner as in Example 1, an electrophotographic photoreceptor of Comparative Example 1 was obtained.

[Comparative Example 2]
The electrophotographic photosensitive member of Comparative Example 2 was obtained in the same manner as in Example 1 except that in the dispersion treatment of the liquid to be processed, the flow rate of the liquid to be processed in the cylinder was 300 mL / min.

[Comparative Example 3]
The electrophotographic photosensitive member of Comparative Example 3 was obtained in the same manner as in Example 1 except that in the dispersion treatment of the liquid to be processed, the flow rate of the liquid to be processed in the cylinder was 600 mL / min.

(Charge exposure test)
Next, each of the electrophotographic photoreceptors of Examples 1 to 4 and Comparative Examples 1 to 3 was subjected to a charging exposure test under normal temperature and normal humidity (temperature 20 ° C., humidity 40%). First, using the electrophotographic photoreceptor, the following steps (A) to (C):
(A) a charging step of charging the electrophotographic photosensitive member with a scorotron charger having a grid applied voltage of −700 V,
(B) An exposure process in which discharge is performed by irradiating light of 10.0 erg / cm ² using a semiconductor laser having a wavelength of 780 nm one second after (A).
(C) A neutralization step of neutralizing by irradiating 50.0 erg / cm ² of red LED light 3 seconds after (A),
Were performed sequentially. At this time, using a laser printer remodeling scanner (modified from XP-15 manufactured by Fuji Xerox Co., Ltd.), the potential V _H at (A), the potential V _L at (B), the potential V _RP at (C). Was measured. The potential variations ΔV _H , ΔV _L and ΔV _RP are obtained from V _H , V _L and V _RP at the initial stage (at the time of one cycle) and after 1 million cycles, and the electrophotographic photosensitive member is repeatedly stabilized based on each variation amount. Sex was evaluated. Further, in the environment of low temperature and low humidity (temperature 10 ° C., relative humidity 15%) and high temperature and high humidity (temperature 28 ° C., relative humidity 85%), potential fluctuation amounts ΔV _H , ΔV _L and ΔV _RP are obtained in the same manner. Based on the amount of variation under each environment, the environmental stability during repeated use of the electrophotographic photoreceptor was evaluated. The results are shown in Table 1. In Table 1, “◯” means that the potential fluctuation amount is small, and “x” means that the potential fluctuation amount is large.

(Production of electrophotographic apparatus and print test)
Moreover, the electrophotographic apparatus which has a structure shown in FIG. 7 was produced using each same electrophotographic photoreceptor of Examples 1-4 and Comparative Examples 1-3. The configuration other than the electrophotographic photosensitive member was the same as that of a full-color printer (Docu Print C620, manufactured by Fuji Xerox Co., Ltd.) having a contact charging device and an intermediate transfer device.

A continuous 10,000-sheet print test using the electrophotographic apparatus obtained in this way, a phenomenon in which a large number of minute spots appear in a portion where an image is not formed and the output image is rough (fogging), and normal The presence or absence of a phenomenon (ghost) in which an undesirable image appears in addition to the position of was evaluated. The results are shown in Table 1. In Table 1, “◯” means that fog or ghost was not recognized, and “x” means that fog or ghost was recognized. Further, “Δ” means that minute spots were observed in the output image.

It is explanatory drawing which shows an example of the horizontal type media mill disperser concerning this invention. (A) And (b) is a graph which shows notionally an example of the media distribution in the cylinder in the distributed processing method of this embodiment, respectively. (A) And (b) is a graph which shows notionally an example of media distribution in the cylinder in the distributed processing method considered conventionally desirable, respectively. (A) And (b) is a graph which shows notionally an example of media distribution in a cylinder at the time of making the rotational speed of a stirring mill slow, respectively. 1 is a schematic cross-sectional view showing a preferred embodiment of an electrophotographic photoreceptor of the present invention. 1 is a schematic configuration diagram showing a preferred embodiment of an electrophotographic apparatus of the present invention. It is a schematic block diagram which shows other embodiment of the electrophotographic apparatus of this invention. 1 is a schematic configuration diagram showing a preferred embodiment of a process cartridge of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Horizontal type media mill disperser (dispersing machine main body), 2 ... Media, 3 ... Cylinder, 4 ... Rotating shaft (shaft), 5 ... Stirring mill, 6 ... Drive apparatus, 7 ... Container (liquid tank to be processed) DESCRIPTION OF SYMBOLS 8 ... Liquid feed pump, 9a ... Upstream inner wall, 9b ... Downstream inner wall, 10 ... Electrophotographic photosensitive member, 12 ... Conductive base, 13 ... Photosensitive layer, 14 ... Undercoat layer, 15 ... Charge generation layer, 16 ... Charge transport layer, 17 ... protective layer, 20 ... length in the central axis direction of the cylinder, 21 ... inner diameter of the cylinder, 40 ... media layer, 50 ... first region, 60 ... second region, 100 ... liquid to be treated, 200 220 ... Electrophotographic device, 207 ... Electrophotographic photosensitive member, 208 ... Charging device, 209 ... Power source, 210 ... Exposure device, 211 ... Developing device, 212 ... Transfer device, 213 ... Cleaning device, 214 ... Staticator, 215 ... Fixing device, 216 ... take Rail, 217 ... Opening for static elimination exposure, 218 ... Opening for exposure, 300 ... Process cartridge, 400 ... Housing, 402a-402d ... Charging roll, 403 ... Laser light source (exposure device), 404a-404d ... Developing device, 405a to 405d ... toner cartridge, 406 ... driving roll, 407 ... tension roll, 408 ... backup roll, 409 ... intermediate transfer belt, 410a to 410d ... primary transfer roll, 411 ... tray (transfer tray) 412 ... Transfer roll, 413 ... Secondary transfer roll, 414 ... Fixing roll, 415a to 415d ... Cleaning blade, 416 ... Cleaning blade, 500 ... Transfer object.

Claims (11)

Using a horizontal media mill disperser comprising a cylinder containing media and a stirring mill provided in the cylinder and rotatable about a rotation axis in a substantially horizontal direction, a coating containing metal oxide fine particles is provided. A method of dispersing a treatment liquid,
While rotating the stirring mill, the liquid to be treated is circulated in the cylinder along the rotation axis direction, the media is unevenly distributed on the downstream side in the cylinder, and a media layer is formed on the downstream inner wall in the cylinder. Forming a distributed processing method.   The liquid to be treated is circulated in the cylinder along the direction of the rotation axis while rotating the stirring mill so that the medium is accumulated over the entire inner wall on the downstream side of the cylinder as viewed from the direction of the rotation axis. The distributed processing method according to claim 1, wherein the medium is unevenly distributed downstream of the cylinder.   The dispersion processing method according to claim 1 or 2, wherein a viscosity of the liquid to be processed is set to 10 mPa · s or more in the cylinder, and a flow rate of the liquid to be processed is set to 800 mL / min or more. The cylinder is substantially cylindrical hollow,
The stirring mill is provided such that the rotation axis thereof is substantially horizontal with respect to the central axis of the cylinder,
The dispersion process according to any one of claims 1 to 3, wherein a length in a central axis direction of the cylinder and an inner diameter of the cylinder satisfy a condition represented by the following formula (1). Method.
L / D ≧ 2 (1)
[In Formula (1), L represents the length (mm) of the center axis direction of a cylinder, D represents the internal diameter (mm) of a cylinder. ] The cylinder is substantially cylindrical hollow,
The stirring mill is provided such that the rotation axis thereof is substantially horizontal with respect to the central axis of the cylinder,
The length in the central axis direction of the cylinder, the inner diameter of the cylinder, and the flow rate of the liquid to be treated in the cylinder satisfy the condition represented by the following formula (2). The distributed processing method as described in any one of them.
D ² L / 1273V ≦ 2.5 (2)
[In formula (2), L represents the length (mm) of the cylinder in the central axis direction, D represents the inner diameter (mm) of the cylinder, and V represents the flow rate of the liquid to be treated (mL / min) in the cylinder. Represent. ]   As the horizontal media mill disperser, a disperser body including the cylinder and the stirring mill, a container for storing the dispersion to be supplied to the cylinder, and the liquid to be processed that flows out of the cylinder after the dispersion treatment The dispersion treatment method according to claim 1, wherein the treatment liquid is dispersed by a circulation method using a disperser including a flow path returning to the container. In the method for producing an electrophotographic photosensitive member in which an undercoat layer and a photosensitive layer are provided in this order on a conductive substrate,
The undercoat layer coating solution preparation step of obtaining a coating solution for the undercoat layer by subjecting the liquid to be treated containing the metal oxide fine particles to a dispersion treatment by the dispersion treatment method according to any one of claims 1 to 6. When,
An undercoat layer forming step of applying the undercoat layer coating solution onto the substrate to form an undercoat layer containing the metal oxide fine particles;
A process for producing an electrophotographic photosensitive member, comprising:   The method for producing an electrophotographic photosensitive member according to claim 7, wherein the metal oxide fine particles are surface-treated with a silane coupling agent.   An electrophotographic photoreceptor obtained by the production method according to claim 7 or 8. An electrophotographic photoreceptor according to claim 9,
A charging device for charging the electrophotographic photosensitive member;
An exposure apparatus that exposes the charged electrophotographic photosensitive member to form an electrostatic latent image;
A developing device for developing the electrostatic latent image to form a toner image;
A transfer device for transferring the toner image from the electrophotographic photosensitive member to a transfer medium;
An electrophotographic apparatus comprising: An electrophotographic photoreceptor according to claim 9,
A charging device for charging the electrophotographic photosensitive member; an exposure device for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image; a developing device for developing the electrostatic latent image to form a toner image; At least one selected from a transfer device that transfers a toner image from the electrophotographic photosensitive member to a transfer medium, and a cleaning device that removes deposits from the electrophotographic photosensitive member after transfer;
A process cartridge comprising:

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