JP2013003397A - Coating device, method for manufacturing electrophotographic photoreceptor, electrophotographic photoreceptor, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating device that sufficiently responses demands for high quality picture characteristics of an electrophotographic photoreceptor.SOLUTION: The coating device includes a coating tank capable of accommodating a conductive support and allowing a coating liquid to fluidize. The coating tank includes: a bottom supply port for supplying the coating liquid; an upper opening for allowing the conductive support to be inserted and flowing out the coating liquid from the coating tank by overflowing; and a linear straightening groove disposed on an inner face of the coating tank. The straightening groove straightens a flow of the coating liquid when the coating liquid is fluidized from the bottom supply port to the upper opening.

Description

  The present invention relates to a coating apparatus, a method for producing an electrophotographic photoreceptor, an electrophotographic photoreceptor, and an image forming apparatus.

An electrophotographic process using a photoconductive photoconductor is one of information recording means utilizing the photoconductive phenomenon of the photoconductor.
In this process, first, the surface of a photoconductor is uniformly charged by corona discharge in a dark place, and then image exposure is performed to selectively discharge the charge of the exposed portion, thereby electrostatically exposing the non-exposed portion. Form an image. Next, colored charged fine particles (toner) are attached to the latent image by electrostatic attraction or the like to form a visible image, thereby forming an image.

As a basic characteristic required for the photoreceptor in these series of processes,
1) It can be charged uniformly to an appropriate potential in a dark place;
2) High charge retention capability in the dark and low charge discharge;
3) It has excellent photosensitivity, and discharges charge quickly by light irradiation;
Etc.
Furthermore, the surface of the photoconductor can be easily neutralized, the residual potential is small, the mechanical strength is excellent, the flexibility is excellent, and the electrical characteristics, especially the chargeability, when repeatedly used. Characteristics such as high stability and durability are required, such as no change in photosensitivity, residual potential, etc., and resistance to heat, light, temperature, humidity, ozone degradation, and the like.

At present, electrophotographic photoreceptors in practical use have a photosensitive layer formed on a conductive support. However, since the carrier injection from the conductive support tends to occur, the surface charge is microscopically observed. An image defect may occur due to disappearance or reduction.
This image defect is prevented, and the surface of the conductive support is subtracted between the conductive support and the photosensitive layer in order to cover defects on the surface of the conductive support, improve the charging property, improve the adhesion of the photosensitive layer, and improve the coating property. A layer (intermediate layer) is provided.

In general, as a method for producing an electrophotographic photoreceptor, a coating solution for forming an intermediate layer or a coating solution for forming a photosensitive layer dissolves or disperses a binder resin in various organic solvents or aqueous solutions. In addition to organic pigments and inorganic pigments in the solution, it is composed of solutions in which various compounds are dissolved or dispersed. By using these coating liquids, a coating film is formed on a conductive support to form an electrophotographic film. In many cases, a photoconductor is manufactured.
Examples of the coating method include a spray method, a bar coating method, a roll coating method, a blade method, a ring method, and a dip coating method.

  Among these, the dip coating method is a method of forming a coating film on a conductive support by immersing the conductive support in a coating tank filled with a coating solution and then pulling it up at a constant speed or a speed that changes sequentially. is there. Since this method is relatively simple and excellent in terms of productivity and cost, it is widely used for producing an electrophotographic photosensitive member.

  In recent years, various high-sensitivity electrophotographic photoreceptors have been developed. However, as the demands for image quality and durability increase, a manufacturing technique capable of fully exhibiting the performance of the electrophotographic photoreceptor is required. That is, in order to obtain high sensitivity and high image quality, an electrophotographic photosensitive member capable of forming a uniform intermediate layer and a photosensitive layer so that there are no slight coating defects and coating irregularities in the intermediate layer and the photosensitive layer formed on the conductive support. There is a need for improvements in manufacturing equipment and manufacturing methods. If there are slight coating defects or coating unevenness in the intermediate layer and photosensitive layer, image defects or image unevenness due to these defects may occur, or the image quality may change due to environmental fluctuations or long-term use, and can be seen in the initial image. In some cases, image defects and image unevenness that have not occurred become apparent.

  Conventionally, the dip coating method, which has been used as a method for producing an electrophotographic photosensitive member having excellent productivity, is a coating solution for an intermediate layer or a photosensitive solution filled in a large coating tank so that a plurality of electrophotographic photosensitive members can be produced simultaneously. The conductive support is immersed in the layer coating liquid, and the coating liquid overflowing when immersed is stored in an overflow tank provided separately from the coating tank, and the coating liquid in the overflow tank is supplied again to the coating tank. Thus, it is common to use an apparatus provided with a circulation path.

  However, it has come to be used in intermediate layer coating liquids in which inorganic pigments are dispersed, photosensitive layer coating liquids in which organic pigments are dispersed, particularly charge generation layer coating liquids, and recent electrophotographic photoreceptors. Application of coating solution for charge transport layer in which inorganic and organic pigments or insoluble resin fine particles are dispersed for the purpose of improving wear resistance and coating solution for forming overcoat layer formed on photosensitive layer When the liquid is repeatedly circulated in the circulation type electrophotographic photoreceptor manufacturing apparatus and supplied to the coating tank, the coating liquid in which various inorganic, organic pigments or insoluble resin fine particles are dispersed is repeatedly circulated in the manufacturing apparatus, and the pigment or resin Aggregates of particles may occur. Such agglomerates may result in very slight coating defects in the intermediate layer, photosensitive layer, or overcoat layer formed on the conductive support, and image defects may become apparent due to environmental changes or long-term use. In some cases, the image quality can be significantly reduced.

  In addition, such a dispersion has a pulsating flow generated from a supply pump when the liquid is circulated, and a flow rate when the dispersion is supplied from the circulation pipe to the application tank or when the liquid overflows in the application tank. Since the flow of the coating solution is disturbed due to the change of the coating layer, uneven coating due to the turbulent flow of the coating solution occurs in the intermediate layer, photosensitive layer, and overcoat layer formed on the conductive support. Cause image unevenness.

  Furthermore, an image forming apparatus equipped with an electrophotographic photosensitive member having very fine coating defects and coating unevenness can be used even when the coating defects and coating unevenness do not affect the image quality at the beginning of use. These fine coating defects and coating unevenness affect the image quality due to changes in the electrical characteristics of the electrophotographic photoreceptor due to environmental changes and long-term use, and the image quality is significantly deteriorated. Such as inability to maintain.

  Therefore, for the purpose of preventing the occurrence of coating unevenness, a coating apparatus that suppresses ring unevenness caused by fluctuations in the top surface of the coating liquid by providing three or more cuts at substantially equal intervals to the opening end of the coating tank ( Patent Document 1) and a coating apparatus (Patent Document 2) in which a spiral rib is provided on the inner wall of a coating tank and the coating liquid flows in the circumferential direction of the immersed conductive support have been proposed.

Japanese Patent No. 2998604 Japanese Patent Laid-Open No. 10-272397

However, in a conventional coating apparatus for producing an electrophotographic photosensitive member, there are problems such as coating unevenness due to the turbulent flow of the coating liquid supplied from the lower part of the coating tank and spiral coating unevenness. May occur.
The present invention has been made in view of such circumstances, and provides a coating apparatus that can sufficiently meet the demand for high quality image quality characteristics of an electrophotographic photosensitive member.

  The present invention includes a coating tank that can accommodate a conductive support and through which a coating liquid can flow. The coating tank can be inserted with a bottom supply port for supplying the coating liquid and the conductive support. And an upper opening for allowing the coating liquid to flow out of the coating tank due to overflow, and a straight rectifying groove provided on the inner surface of the coating tank, the rectifying groove extending from the bottom supply port Provided is a coating apparatus characterized by rectifying the coating liquid when the coating liquid is caused to flow into the upper opening.

  According to the present invention, since the coating tank having the straight rectifying groove is provided on the inner surface, the flow of the coating liquid supplied from the bottom supply port at the bottom of the coating tank and flowing so as to overflow from the upper opening is rectified. It is possible to suppress the occurrence of turbulent flow in the coating liquid flowing in the coating tank. Thereby, it is possible to suppress the occurrence of coating unevenness due to the turbulent flow of the coating liquid, and to form a coating film on the surface of the conductive support.

It is a schematic sectional drawing which shows the structure of the coating device of one Embodiment of this invention. It is a schematic perspective view of the application tank etc. which are contained in the coating device of one embodiment of the present invention. It is a schematic top view of the coating tank etc. which are contained in the coating device of one Embodiment of this invention. FIG. 4 is a schematic cross-sectional view of a coating tank and the like taken along dotted line AA in FIG. 3. FIG. 4 is a schematic cross-sectional view of a coating tank and the like taken along one-dot chain line BB in FIG. 3. It is a schematic top view of the coating tank etc. which are contained in the coating device of one Embodiment of this invention. It is a schematic top view of the coating tank etc. which are contained in the coating device of one Embodiment of this invention. It is a schematic top view of the coating tank etc. which are contained in the coating device of one Embodiment of this invention. (A)-(c) is a schematic top view of the coating tank contained in the coating device of one Embodiment of this invention, respectively. (A)-(c) is a schematic top view of the coating tank contained in the coating device of one Embodiment of this invention, respectively. (A)-(c) is a schematic top view of the coating tank contained in the coating device of one Embodiment of this invention, respectively. It is a schematic top view of the coating tank etc. which are contained in the coating device of one Embodiment of this invention. FIG. 13 is a schematic cross-sectional view of a coating tank and the like taken along dotted line CC in FIG. 12. FIG. 13 is a schematic cross-sectional view of a coating tank and the like taken along one-dot chain line DD in FIG. 12. (A) is an enlarged view of a range E surrounded by a dotted line in FIG. 14, (b) (c) is a schematic enlarged view of a coating tank and the like included in the coating apparatus of one embodiment of the present invention, Corresponds to (a). 1 is a schematic plan view of an electrophotographic photosensitive member according to an embodiment of the present invention. FIG. 17 is a schematic cross-sectional view of the electrophotographic photosensitive member taken along dotted line FF in FIG. 16. FIG. 18 is an enlarged cross-sectional view of the electrophotographic photosensitive member in a range G surrounded by a dotted line in FIG. 17. 1 is a schematic cross-sectional view of an electrophotographic photosensitive member according to an embodiment of the present invention. 1 is a schematic cross-sectional view of an electrophotographic photosensitive member according to an embodiment of the present invention. 1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment of the present invention. It is a schematic top view of a coating tank and the like used in an electrophotographic photoreceptor manufacturing experiment.

  The coating apparatus of the present invention includes a coating tank that can accommodate a conductive support and through which a coating liquid can flow. The coating tank includes a bottom supply port for supplying a coating liquid, and the conductive support. And an upper opening through which the coating liquid flows out of the coating tank due to overflow, and a straight rectifying groove provided on the inner surface of the coating tank, the rectifying groove having the bottom portion When the coating liquid flows from the supply port to the upper opening, the coating liquid is rectified.

In the coating apparatus of the present invention, it is preferable that the upper opening includes an outflow groove provided at an end of a side wall of the coating tank.
According to such a configuration, the coating liquid flowing out from the upper opening can be preferentially overflowed from the outflow groove, and the flow of the coating liquid flowing through the coating tank can be stabilized.
In the coating apparatus of the present invention, it is preferable that two or more outflow grooves are provided at equal intervals.
According to such a configuration, when the coating liquid stored in the coating tank overflows from the upper opening, the liquid level can be stabilized.

In the coating apparatus of the present invention, it is preferable that the outflow groove is a groove connected to the rectifying groove.
According to such a configuration, a flow of the coating liquid from the rectifying groove toward the outflow groove can be created, and the rectifying effect of the outflow groove and the rectifying groove can be enhanced.
In the coating apparatus of the present invention, it is preferable that the coating tank has a cylindrical shape, and one end is a bottom and the other end is the upper opening.
According to such a structure, it can suppress that a turbulent flow arises in the coating liquid which flows through the inside of a coating tank.
In the coating apparatus of the present invention, it is preferable that the rectifying groove is provided substantially in parallel with a cylindrical axial direction of the coating tank.
According to such a configuration, the rectification effect of the coating liquid flowing from the bottom supply port to the upper opening by the rectification groove can be enhanced.

The present invention is also a method for producing an electrophotographic photosensitive member using the apparatus of the present invention, wherein the conductive support is immersed in a coating solution stored in the coating tank; and the conductive support. The step of taking out the conductive support from the coating solution also provides a method for producing an electrophotographic photosensitive member with an overflow of the coating solution from the upper opening.
According to the method for producing an electrophotographic photosensitive member of the present invention, a coating film in which the occurrence of coating unevenness is suppressed can be formed on the surface of a conductive support. Can be manufactured.
In the method for producing an electrophotographic photosensitive member of the present invention, the upper opening includes an outflow groove provided at an end of a side wall of the coating tank, and the step of taking out the conductive support from the coating solution includes the outflow It is preferable that the coating liquid overflows from the groove.
According to such a configuration, a coating film in which the occurrence of coating unevenness is suppressed can be formed on the surface of the conductive support.

In the method for producing an electrophotographic photosensitive member of the present invention, the coating solution stored in the coating tank is preferably a dispersion in which at least one of an inorganic pigment, an organic pigment, and insoluble resin fine particles is dispersed.
According to such a configuration, an electrophotography is obtained by applying a dispersion liquid in which at least one of an inorganic pigment, an organic pigment, and insoluble resin fine particles is dispersed on the surface of the conductive support while suppressing coating unevenness. A photoreceptor can be manufactured.
In the method for producing an electrophotographic photosensitive member of the present invention, the coating solution stored in the coating tank is preferably an undercoat layer coating solution.
According to such a configuration, an electrophotographic photoreceptor having an undercoat layer in which coating unevenness is suppressed can be manufactured.
In the method for producing an electrophotographic photosensitive member of the present invention, the coating solution stored in the coating tank is preferably a charge generating layer coating solution.
According to such a configuration, an electrophotographic photosensitive member provided with a charge generation layer in which coating unevenness is suppressed can be manufactured.

The present invention also provides an electrophotographic photosensitive member produced by the coating apparatus of the present invention or the method for producing an electrophotographic photosensitive member of the present invention.
According to the electrophotographic photosensitive member of the present invention, an electrophotographic photosensitive member having an undercoat layer, a photosensitive layer or an overcoat layer in which coating unevenness is suppressed can be provided.
The present invention also provides an image forming apparatus equipped with the electrophotographic photosensitive member of the present invention.
According to the image forming apparatus of the present invention, it is possible to print while suppressing image defects due to coating unevenness of the undercoat layer, photosensitive layer or overcoat layer of the electrophotographic photosensitive member.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The configurations shown in the drawings and the following description are merely examples, and the scope of the present invention is not limited to those shown in the drawings and the following description.

Configuration of Coating Apparatus and Coating Method FIG. 1 is a schematic cross-sectional view showing the configuration of the coating apparatus of the present embodiment, and FIG. 2 is a schematic perspective view of a coating tank and the like included in the coating apparatus of the present embodiment. FIG. 3 is a schematic top view of the coating tank and the like included in the coating apparatus of the present embodiment, FIG. 4 is a schematic cross-sectional view of the coating tank and the like along the dotted line AA in FIG. 3, and FIG. FIG. 3 is a schematic cross-sectional view of a coating tank and the like taken along a three-dot chain line BB in FIG.
Moreover, FIGS. 6-8 is a schematic top view of the coating tank etc. which are respectively included in the coating device of this embodiment, and is a schematic top view corresponding to FIG. Moreover, Fig.9 (a) -11 (c) is a schematic top view of the coating tank contained in the coating device of this embodiment, respectively.
12 is a schematic top view of a coating tank and the like included in the coating apparatus of the present embodiment, FIG. 13 is a schematic cross-sectional view of the coating tank and the like taken along a dotted line CC in FIG. 12, and FIG. 12 is a schematic cross-sectional view of a coating tank and the like taken along a dashed-dotted line DD in FIG.

The coating apparatus 20 of the present embodiment includes a coating tank 1 that can accommodate the conductive support 3 and can flow the coating liquid, and the coating tank 1 includes a bottom supply port 6 for supplying the coating liquid, The conductive support 3 can be inserted, and has an upper opening 7 through which the coating liquid flows out of the coating tank 1 due to overflow, and a straight rectifying groove 9 provided on the inner surface of the coating tank 1, The rectifying groove 9 rectifies the coating liquid when the coating liquid flows from the bottom supply port 6 to the upper opening 7.
Further, the coating apparatus 20 of the present embodiment stirs the coating liquid, the overflow tank 10 for storing the coating liquid overflowing from the coating tank 1, the circulation path 12 for circulating the coating liquid 5 stored in the coating tank 1, and the coating liquid. A stirring tank 14, a stirring device 15, and an elevating device 16 for immersing the conductive support 3 in the coating solution can also be provided.
Hereinafter, the coating apparatus 20 of this embodiment will be described.

1. Coating Tank The coating tank 1 included in the coating apparatus 20 of this embodiment can store the coating liquid 5 used for forming a coating film on the surface of the conductive support 3. The coating tank 1 may have a cylindrical shape with a bottom or a cylindrical shape with a bottom. Further, the coating tank 1 has a bottom part 2 and a bottom part supply port 6 for supplying the coating liquid to the coating tank 1 at the bottom part 2. Thereby, the coating liquid can be supplied to the coating tank 1 from the bottom 2 side. For example, the coating tank 1 can be made into a cylindrical shape as shown in FIGS.

  The coating tank 1 has an upper opening 7 through which the coating liquid flows out of the coating tank 1 due to overflow. Thereby, the coating liquid supplied to the coating tank 1 from the bottom part supply port 6 can be flowed out from the upper opening 7, and a coating liquid can be distribute | circulated. The upper opening 7 is provided so that the conductive support 3 can be inserted. By inserting the conductive support 3 into the upper opening 7, the conductive support 3 can be immersed in the coating solution stored in the coating tank 1, and the conductive support 3 immersed in this coating solution is applied. By pulling up from the liquid, a coating film can be formed on the surface of the conductive support 3.

The coating tank 1 has a straight rectifying groove 9 on its inner surface. As a result, the coating liquid flowing through the coating tank 1 can be rectified, and turbulent flow of the coating liquid can be suppressed.
The rectifying groove 9 provided inside the coating tank 1 of the present embodiment is preferably provided along the flow of the coating liquid supplied into the coating tank 1. FIG. 1 shows the case where the coating liquid supplied from the lower part of the coating tank 1 is supplied upward from the liquid feeding pump 17 toward the upper opening 7 at the upper end of the coating tank 1. The rectifying groove 9 to be formed is formed by forming a groove in the vertical direction of the coating tank 1.
Two or more rectifying grooves 9 are preferably provided at equal intervals along the circumferential direction of the coating tank 1. In the case of only one, the effect of suppressing the disturbance of the coating liquid flowing in the coating tank 1 is thin, and the effect of eliminating coating unevenness by suppressing the inclination of the coating tank 1 and the flow rate and flow rate of the supplied coating liquid. Is not preferable because it not only significantly decreases, but also promotes uneven coating.

Further, for example, as shown in FIGS. 2 to 5, 9 (a), 10 (a), and 11 (a), two rectifying grooves 9 can be provided on the inner surface of the application tank 1. The straight rectifying groove 9 extending from the bottom 2 of 1 to the upper opening 7 can be formed. The two rectifying grooves 9 can be provided at equal intervals on the inner surface of the coating tank 1. In the example of FIGS. 2-5, since the coating tank 1 is cylindrical shape, two rectification grooves can be provided facing each other.
Also, for example, as shown in FIGS. 9B, 10B, 11B, and 12 to 14, three rectifying grooves 9 can be provided on the inner surface of the coating tank 1, and the coating tank The straight rectifying groove 9 extending from the bottom 2 of 1 to the upper opening 7 can be formed. The three rectifying grooves 9 can be provided at equal intervals on the inner surface of the coating tank 1.
Further, as shown in FIGS. 9C, 10C, and 11C, four rectifying grooves 9 may be provided, or five or six may be provided. Moreover, you may provide the number in the range of 7-15.

The shape of the rectifying groove 9 provided in this embodiment is a U-shaped form (type) having a side wall and a bottom as shown in FIGS. 2 to 5, 8, 9 (a) to 9 (c), and 12 to 14. A) may be used. The U-shaped bottom may be a curved surface as shown in FIG. 3 or a flat surface as shown in FIG. Further, the shape of the rectifying groove 9 may be a V-shaped form (type B) as shown in FIGS. 6 and 10A to 10C, and FIGS. A semicircular shape (type C) as shown in FIG.
Further, the rectifying groove 9 can have a substantially constant width, and can have a substantially constant depth.

  When the coating tank 1 has a cylindrical shape and one end is the bottom 2 and the other end is the upper opening 7, the rectifying groove 9 is substantially parallel to the axial direction of the cylindrical shape of the coating tank 1. It may be. As a result, the coating liquid can be rectified in the direction from the bottom 2 toward the upper opening 7, and the turbulent flow of the coating liquid can be suppressed.

  Furthermore, it is preferable to provide an outflow groove 8 (notch) at the upper end of the coating tank 1 on the circumference of the upper opening 7 in accordance with the position of the rectifying groove 9 provided inside the coating tank 1. When the coating liquid flowing in the coating tank 1 overflows due to this cutting, the effect of flowing out uniformly in the circumferential direction of the upper end portion of the coating tank 1 is enhanced, and the flow of the liquid surface of the coating liquid becomes radial and uniform. Therefore, the flow of the liquid surface is smooth, and the effect of forming a coating film free from ring unevenness and streak unevenness due to liquid surface fluctuation is enhanced.

  However, when the position of the rectifying groove 9 provided inside the coating tank 1 and the position of the outflow groove 8 are shifted, or when the interval between the positions of the outflow groove 8 at the upper end of the coating tank 1 is provided unevenly When the coating liquid flowing into the coating tank 1 overflows from the upper opening 7 at the upper end of the coating tank 1 through the outflow groove 8, a flow of the coating liquid in the circumferential direction of the coating tank 1 occurs. Since the flow becomes non-uniform, ring-shaped streak unevenness is generated on the conductive support 3, which is not preferable.

The shape of the outflow groove 8 provided on the circumference of the upper end of the coating tank 1 in this embodiment is, for example, a U-shaped groove as shown in FIGS. 2 to 5, FIGS. 12 to 14, and FIG. Alternatively, it may be a V-shaped groove as shown in FIG. 15B or a semicircular groove as shown in FIG. However, it is not limited to these forms.
It is preferable to provide two or more outflow grooves 8 at equal intervals along the circumferential direction of the upper end opening of the coating tank. In the case of only one, the supply amount of the coating liquid is small when overflowing from the upper end opening of the coating tank, and when it does not flow from the entire opening, it overflows from one direction, and the conductive support 3 is detached from the coating liquid. Since the coating liquid adhering to the surface affects the flow of the coating liquid on the liquid surface, ring-shaped streak unevenness occurs, which is not preferable.

  In the case of only one, the supply amount of the coating liquid is sufficient, and even when it flows from the entire upper end opening of the coating tank, the flow rate of the coating liquid is large and the flow rate is high, so it flows uniformly along the rectifying groove 9 on the inner wall of the coating tank. When the applied coating liquid overflows, it flows more into the outflow groove, so that the flow of the coating liquid becomes more turbulent and causes uneven coating, which is not preferable.

2. Coating Solution The coating solution stored in the coating tank 1 is not limited as long as it is a coating solution that is applied onto the surface of the conductive support 3. For example, the coating solution may be an undercoat layer coating solution, or a photosensitive layer coating solution. (Including a charge generation layer coating solution and a charge transport layer coating solution) or an overcoat layer coating solution. The method for preparing these coating solutions will be described in “Configuration of electrophotographic photoreceptor” described later.
The coating liquid may be a dispersion liquid in which at least one of an inorganic pigment, an organic pigment, and insoluble resin fine particles is dispersed.

3. Overflow tank The overflow tank 10 is provided so that the coating liquid overflowing from the upper opening 7 of the coating tank 1 can be stored. Further, the overflow tank 10 can be electrically connected to the stirring tank 14 via the circulation path 12.

4). Stirring tank and stirrer The stirring tank 14 can store a coating solution and can stir the coating solution. Further, the stirred coating liquid can be supplied to the coating tank 1 through the circulation path 12. By this, the sufficiently stirred uniform coating liquid can be supplied to the coating tank 1, and the quality of the coating liquid in the coating tank 1 can be stabilized.
Further, the stirring tank 14 can include a stirring device 15. Thus, the coating solution stored in the stirring tank 14 can be stirred by the stirring device 15.

5. Pump The pump 17 can be provided to supply the coating liquid to the coating tank 1. The pump 17 can be provided in the circulation path 12 that connects the stirring tank 14 and the coating tank 1.

6). Lifting Device The lifting device 16 can be connected to the conductive support 3 and can lift and lower the conductive support 3. The elevating device 16 is connected to the conductive support 3 and can be provided so that the conductive support 3 is immersed in a coating solution stored in the coating tank 1 when the conductive support 3 is lowered. The lifting device 16 can be provided so that the conductive support 3 can be lifted from the coating solution stored in the coating tank 1 when the conductive support 3 is raised. As a result, it is possible to apply the coating liquid on the surface of the conductive support 3 using the lifting device 16 and form a coating film.

Method for Producing Electrophotographic Photoreceptor This embodiment also provides a method for producing electrophotographic photoreceptor 30 using coating apparatus 20 of this embodiment.
The method of manufacturing the electrophotographic photosensitive member 30 according to the present embodiment is a method of manufacturing the electrophotographic photosensitive member 30 using the coating apparatus 20 including the coating tank 1 provided with the rectifying grooves 9 and is stored in the coating tank 1. The step of immersing the conductive support 3 in the coating solution and the step of taking out the conductive support 3 from the coating solution, and the step of taking out the conductive support 3 from the coating solution, Accompanied by overflow of coating solution.
By using an undercoat layer coating solution, a photosensitive layer coating solution, a charge generation layer coating solution or a charge transport layer coating solution, and an overflow layer coating solution formed as necessary, The electrophotographic photoreceptor 30 can be manufactured.

[Dip coating method]
Conventionally, as a method of manufacturing an electrophotographic photoreceptor, a dipping method is available because a plurality of coatings can be simultaneously performed, manufacturing conditions can be maintained with relatively easy manufacturing equipment, and coating film can be easily controlled. Generally adopted in many cases.
First, a dip coating method for forming a coating film on the surface of the conductive support 3 using the coating apparatus 20 will be described.
The dip coating method is a method of forming a coating film on the conductive support 3 by immersing the conductive support 3 in a coating tank 1 filled with a coating solution and then pulling it up at a constant speed or a speed that changes sequentially. is there. Since this method is relatively simple and excellent in terms of productivity and cost, it is widely used for manufacturing a photoreceptor. In addition, you may provide the coating liquid dispersion | distribution apparatus represented by the ultrasonic generator in the apparatus used for the dip coating method in order to stabilize the dispersibility of a coating liquid.

  However, the dip coating method immerses the conductive support 3 in a coating tank 1 filled with a photoreceptor coating solution such as a charge generation layer coating solution, a charge transport layer coating solution or a single layer type photosensitive layer coating solution. After that, the photosensitive layer 24 can be formed by pulling it up at a constant speed or a speed that changes sequentially, and is relatively simple and excellent in productivity and cost. Therefore, the electrophotographic photosensitive member 30 is manufactured. It is used a lot when you do.

  More specifically, in the dip coating apparatus 20 shown in FIG. 1, the coating liquid 5 is accommodated inside the coating liquid tank 1 and the stirring tank 14. The coating liquid 5 is sent from the stirring tank 14 to the coating liquid tank 1 through the circulation path 12 by the pump 17. The coating solution 5 in the coating tank 1 overflows from the upper opening 7, flows into the overflow tank 10, and is sent from the overflow tank 10 to the stirring tank 14 through an inclined circulation path 12 that connects the overflow tank 10 and the upper part of the stirring tank 14. And thus circulated.

On the upper part of the coating liquid tank 1, the conductive support 3 is attached to the rotary shaft 19 of the lifting device 6. The axial direction of the rotary shaft 19 is along the vertical direction of the coating liquid tank 1, and the attached conductive support 3 is moved up and down by rotating the rotary shaft 19 with the motor 18. The conductive support 3 is lowered by rotating the motor 18 in one predetermined direction, and immersed in the coating liquid 5 inside the coating liquid tank 1.
Next, the motor 18 is rotated in the other direction opposite to the one direction to raise the conductive support 3, lifted from the coating solution 5, and dried to form a coating film with the coating solution 5.

[Points to note about the dip coating method]
Here, the points to be noted about the dip coating method are mainly described.
In order to form a uniform thin film free from coating defects and coating unevenness on the undercoat layer 22, the photosensitive layer 24, and the overcoat layer 29 formed on the conductive support, the coating solution supplied to the coating tank is supplied at a constant flow rate. While maintaining the conductive support 3 at a constant speed, the conductive support 3 is pulled up, and no difference in film thickness occurs between the coating start position and the coating end position. Fine control and management on equipment are required for the coating conditions, such as continuously changing the relative speed between the conductive support 3 and the liquid surface.

  For example, the relative speed between the conductive support 3 and the coating liquid is changed even if the pumping capacity of the pump for supplying the coating liquid changes or the supply amount of the coating liquid slightly varies due to pulsating flow. In some cases, the coating liquid adhering to the conductive support 3 changes and ring unevenness or streak unevenness occurs even though it is determined by dip coating. Since such coating unevenness becomes an image defect and affects the image quality, it is important not to generate coating unevenness such as ring unevenness and stripe unevenness.

  In addition, the coating liquid supplied into the coating tank may flow non-uniformly while flowing through the coating tank and overflowing from the upper opening 7 after being supplied from the pump. In some cases, the amount of coating liquid to be formed on the support 3 changes, and uneven coating such as streaks due to disturbance of the coating liquid may occur. This is because, when dip coating is performed, in order to improve the production efficiency of the photoconductor, when a plurality of coatings are applied at the same time, the flow rate of the coating liquid supplied to the coating tank is not necessarily the same depending on the position to be coated. This is considered to be caused by the inclination of the turbulent flow and the turbulent flow generated in the coating liquid flowing in the coating tank 1.

  Furthermore, when the coating liquid overflows from the upper end opening of the coating tank, it is facilitated by the inclination of the coating tank and the flow rate when flowing to the inside of the coating tank or the upper opening of the coating tank. The position where it overflows from the upper opening changes, the bias occurs when viewed from the circumference of the conductive support 3, the film thickness becomes uneven in the circumferential direction of the conductive support 3, In some cases, this may cause uneven coating.

  In particular, in the case of a coating liquid in which inorganic pigments, organic pigments, and insoluble resin fine particles are dispersed, circulation to supply and circulate via a liquid feed pump such as a piping, coating tank, and overflow tank of a coating apparatus that is an electrophotographic photoreceptor manufacturing apparatus. In the electrophotographic photoreceptor manufacturing apparatus of the above type, the flow rate and flow rate of the coating liquid change, and the flow of the coating liquid is disturbed, so that the dispersion state of the pigment in the coating liquid becomes non-uniform and agglomerates. Application defects such as application unevenness may occur.

  Further, when forming the undercoat layer 22 or the like using such a dip coating apparatus 20, the pump 17 that supplies the coating liquid is used for a long period of time to reduce the feeding ability, generate pulsating flow, or overflow from the overflow tank 10. Amount of coating liquid to be applied formed on the conductive support 3 by turbulent flow in the coating liquid due to fluctuations in flow rate and flow velocity when supplied to the coating tank via the pipe and the liquid feed pump 17. May slightly change or cause unevenness in the concentration distribution of dispersed metal oxide fine particles and the like, which may cause uneven coating.

[Dip coating method using the coating apparatus of this embodiment]
However, the present inventor caused the coating liquid in the coating tank 1 to overflow from the upper opening of the coating tank when dipping the conductive support 3 in the coating liquid filled in the coating tank 1. Thereafter, in the apparatus for removing the conductive support 3 from the coating tank 1 to form a coating film on the support 3, a straight rectifying groove is provided on the inner surface of the coating tank so that there is no uniform coating defect. The coating device which can form a film thickness was discovered.
This is because the flow of the coating liquid flowing in the coating tank 1 is not disturbed by providing the rectifying groove 9 inside the coating tank as in this embodiment, and there is no vertical streak or ring-shaped coating unevenness. It is considered that the undercoat layer 22 and the like can be formed.
In addition, the electrophotographic photoreceptor 30 manufactured using the coating apparatus of the present embodiment forms a uniform film without coating defects and coating unevenness, and the image forming apparatus 45 on which the photoreceptor 30 is mounted can be used in each environment. The present inventors have found that an excellent image free from image quality defects can be provided even when used for a long time.

  Further, when the conductive support 3 immersed in the coating liquid stored in the coating tank 1 is pulled up from the coating liquid, the coating liquid is supplied to the coating tank 1 so that the coating liquid overflows from the upper opening 7. be able to. Accordingly, even when the conductive support 3 is pulled up, the flow of the coating liquid in the coating tank can be set in the direction from the bottom 2 toward the upper opening 7, and the turbulent flow of the coating liquid occurs in the coating tank. This can be suppressed.

Furthermore, when extending the life of electrophotographic photoreceptors in recent years, wear resistance is improved especially for inorganic pigments such as alumina and silica and fluororesin fine particles in the charge transport layer and overcoat layer, which are the outermost surface layers of the photoreceptor. Even in the case of forming a charge transport layer coating solution or an overcoat layer coating solution to which such a filler is added, coating with no coating defects can be achieved by using the coating apparatus of this embodiment. An electrophotographic photoreceptor having a film formed can be obtained.
Furthermore, if the outflow groove 8 is provided at equal intervals along the circumference of the upper end opening of the application tank along the rectifying groove 9 provided in the inside of the application tank 1, the outflow groove 8 is provided because the application liquid flows evenly. This is considered to be effective in forming a uniform coating film because the liquid level of the coating liquid is not disturbed and non-uniform flow does not occur.

Configuration of Electrophotographic Photoreceptor This embodiment also provides an electrophotographic photoreceptor produced using the coating apparatus of this embodiment.
FIG. 16 is a schematic plan view of the electrophotographic photosensitive member of this embodiment, and FIG. 17 is a schematic cross-sectional view of the electrophotographic photosensitive member taken along a dotted line FF in FIG. FIG. 18 is an enlarged cross-sectional view of the electrophotographic photosensitive member in a range G surrounded by a dotted line in FIG. 19 and 20 are schematic cross-sectional views of the electrophotographic photosensitive member of this embodiment, and correspond to FIG.
The electrophotographic photoreceptor 30 has a conductive support 3 and a photosensitive layer 24 on the surface of the conductive support 3. In addition, the electrophotographic photoreceptor 30 may include an undercoat layer 22 between the conductive support 3 and the photosensitive layer 24, and may include an overcoat layer 29 on the photosensitive layer 24.

1. Conductive Support The conductive support 3 serves as an electrode for the electrophotographic photoreceptor 30 and also functions as a support member for other layers.
The constituent material of the conductive support 3 is not particularly limited as long as it is a material used in this field.
Specifically, metals and alloy materials such as aluminum, aluminum alloy, copper, brass, zinc, nickel, stainless steel, chromium, molybdenum, vanadium, indium, titanium, gold, platinum: polyethylene terephthalate, polyamide, polyester, polyoxy Polymer material such as methylene, polystyrene, cellulose, polylactic acid, hard paper, glass substrate laminated with metal foil, metal material or alloy material deposited, conductive polymer, tin oxide, oxidation Examples thereof include those obtained by depositing or applying a layer of a conductive compound such as indium or carbon black.

  Examples of the shape of the conductive support 3 generally include a sheet shape, a cylindrical shape, a columnar shape, and an endless belt (seamless belt) shape. When the method of immersing in the coating tank 1 filled with the coating solution for forming the undercoat layer 22, the photosensitive layer 24, the overcoat layer 29, etc. on the cylinder 3, the cylindrical shape is relatively easy to handle. Conductive support 3 is preferred.

If necessary, the surface of the conductive support 3 is irregularly reflected within a range that does not affect the image quality, such as anodic oxide coating, chemical treatment, surface treatment with hot water, coloring treatment, or roughening the surface. Processing may be performed.
The irregular reflection treatment is particularly effective when the electrophotographic photosensitive member 30 of the present embodiment is used in an electrophotographic process using a laser as an exposure light source.
That is, in the electrophotographic process using a laser as an exposure light source, the wavelengths of the laser light are uniform, so that the laser light reflected on the surface of the electrophotographic photosensitive member 30 and the laser light reflected inside the electrophotographic photosensitive member 30. Cause interference, and interference fringes due to this interference may appear in the image and cause image defects. Therefore, by performing irregular reflection processing on the surface of the conductive support 3, image defects due to interference of laser light having a uniform wavelength can be prevented.

2. Undercoat layer The following can be used as an example of the undercoat layer 22, but is not limited to the undercoat layer 22, and the charge is formed on the conductive support 3 without forming the undercoat layer 22. Photosensitive layers 24 such as the generation layer 26 and the charge transport layer 27 may be provided. For example, the undercoat layer 22 can be provided between the conductive support 3 and the photosensitive layer 24 as shown in FIGS.

The undercoat layer 22 has a function of preventing charge injection from the conductive support 3 to the photosensitive layer 24 (single-layer type photosensitive layer or laminated type photosensitive layer) (which serves as a barrier against hole injection).
That is, the undercoat layer 22 suppresses a decrease in chargeability of the single layer type photosensitive layer or the multilayer type photosensitive layer, suppresses a decrease in surface charge other than a portion to be erased by exposure, and causes image defects such as fogging. Is prevented.
In particular, during image formation by the reversal development process, it is possible to prevent the occurrence of image fogging called black spots in which minute black dots made of toner are formed on a white background portion.

In addition, the undercoat layer 22 covering the surface of the conductive support 3 reduces the degree of unevenness, which is a defect on the surface of the conductive support 3, and makes the surface uniform. The film formability of the layer can be improved, and the adhesion (adhesiveness) between the conductive support 3 and the single-layer type photosensitive layer or the multilayer type photosensitive layer can be improved.
The electrophotographic photosensitive member 30 on which the undercoat layer 22 is formed originates from defects in the conductive support 3 while maintaining predetermined electrical characteristics between the conductive support 3 and the photosensitive layer 24. Image defects can be prevented.

  In particular, in the electrophotographic photoreceptor 30 in which the undercoat layer 22 is formed, the electrophotographic photoreceptor 30 is manufactured using an organic material having photosensitivity with respect to a long wavelength, such as a phthalocyanine pigment, as the charge generation material. By mounting the photographic photosensitive member 30 on an image forming apparatus using a reversal development method, an excellent image having no small black spots (black spots) on a white background peculiar to reversal development due to reduction or disappearance of surface charge in a minute region. The characteristic can be exhibited.

In general, the electrophotographic photoreceptor 30 includes a conductive support 3, an undercoat layer 22 formed on the conductive support 3, and a photosensitive layer 24 formed on the undercoat layer 22. In the electrophotographic photoreceptor 30, the thickness of the undercoat layer 22 is preferably about 0.05 to 10 μm.
When the thickness of the undercoat layer 22 is reduced, the electrical characteristics associated with the environmental variation of the electrophotographic photosensitive member 30 are less changed and show stable characteristics, but the adhesion between the conductive support 3 and the photosensitive layer 24 is reduced. In some cases, an image defect due to the defect of the conductive support 3 may occur.

On the other hand, when the thickness of the undercoat layer 22 is increased, there is a problem that sensitivity is lowered and stability characteristics against environmental fluctuations are deteriorated, which is practical for achieving both reduction of image defects and improvement of stability of electrical characteristics. This is a factor that limits the thickness of the film.
However, various studies have been made for suppressing fluctuations in photoreceptor characteristics, particularly sensitivity and residual potential, and preventing the occurrence of image fogging. However, the undercoat layer 22 is composed of metal oxide fine particles, In particular, by containing titanium oxide fine particles or zinc oxide fine particles, the electrical characteristics of the undercoat layer 22 can be improved, and if the coating film can be formed flat, the resistance value of the undercoat layer 22 can be kept uniform. Since the electrophotographic photosensitive member 30 and the image forming apparatus that can stably exhibit excellent image quality under the respective periods and in various environments can be obtained, many products in which metal oxide particles are dispersed in the undercoat layer 22 have been developed.

  The undercoat layer 22 can contain metal compound fine particles and a binder resin as main components, and the undercoat layer coating solution is prepared by dispersing the binder resin and metal compound fine particles in an organic solvent using a disperser. Can do. The undercoat layer 22 can be formed, for example, by dip-coating an undercoat layer coating solution on the surface of the conductive support 3.

[Distributor]
First, the disperser used for preparing the undercoat layer coating solution will be described. This disperser can also be used for preparing a photosensitive layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution.
As a method for dispersing the coating solution for the undercoat layer, an ultrasonic disperser that does not use a dispersion medium or a disperser such as a ball mill, a bead mill, or a paint conditioner that uses a dispersion medium can be used. A binder dissolved in an organic solvent can be used. A disperser using a dispersion medium in which an inorganic compound is charged into the resin solution and the inorganic compound can be dispersed with a strong force applied from the disperser through the dispersion medium is preferable.

As the material of the dispersion medium, it is preferable to use glass, zircon, alumina, titanium, preferably zirconia or titania having high wear resistance.
The shape of the dispersion medium may be any shape and size such as a bead shape of about 0.3 mm to several mm and a ball shape of about several cm.
When glass is used as the material of the dispersion medium, it is not preferable because the viscosity of the dispersion increases and storage stability deteriorates.

[Metal compound fine particles]
The metal compound fine particles dispersed in the undercoat layer 22 adjust the volume resistance value of the undercoat layer 22 when the electrophotographic photosensitive member 30 is formed, thereby preventing carrier injection from the conductive support 3 to the photosensitive layer 24. In addition, it has a function of maintaining the electrical characteristics of the electrophotographic photosensitive member 30 under various environments.
Examples of the metal compound fine particles dispersed in the undercoat layer 22 include titanium oxide, aluminum oxide, tin oxide, zinc oxide, antimony oxide, silicon oxide, indium oxide, zirconium oxide, magnesium oxide, and barium sulfate. Among these, titanium oxide, zinc oxide, and aluminum oxide are preferable, and titanium oxide and zinc oxide are particularly preferable.

  When the metal compound fine particles are titanium oxide or zinc oxide fine particles, the powerful force applied from the disperser used when preparing the coating liquid for forming the undercoat layer 22 is reduced by the titanium oxide or zinc oxide fine particles. It is used not only as energy to disperse, but also as energy to wear the dispersion medium itself, the cylinder inner wall that contains the dispersion medium, and the rotating disk that stirs the dispersion medium, and these materials are scraped and mixed into the dispersion coating liquid. This is considered to have some influence on the dispersibility and storage stability of the dispersion coating solution and on the coating property and the film quality of the undercoat layer 22 when forming the undercoat layer 22 of the photoreceptor.

The crystal form of titanium oxide used for the metal compound fine particles may be any of rutile, anatase, and amorphous, and the shape thereof is generally granular, but is needle-like or dendritic. Is preferred.
Here, the term “needle shape” may be an elongated shape including a rod shape, a columnar shape, a spindle shape, etc., and does not necessarily have to be extremely elongated and does not necessarily have a sharp tip.
Similarly, the term “dendritic shape” refers to an elongated shape including a rod shape, a columnar shape, a spindle shape, or the like, that is, a shape in which the above needle shape is branched, called a dendritic shape.

The particle diameter of the acicular or dendritic titanium oxide fine particles is preferably such that the major axis length a is 100 μm or less and the minor axis length b is 1 μm or less, more preferably the major axis length a is 10 μm or less. Is 0.5 μm or less, and the needle shape refers to a shape having an aspect ratio of 1.5 or more, which is a ratio a / b of the major axis length a to the minor axis length b.
If the axial length of these needles or dendrites is larger than this range, it is difficult to obtain an undercoat layer coating solution having dispersion stability.
Furthermore, the aspect ratio of the fine particles is preferably in the range of 1.5 to 300, more preferably in the range of 2 to 10.
As a method of measuring the particle size and aspect ratio, it is possible to measure by a method such as gravimetric sedimentation method or light transmission particle size distribution measurement method, but it is better to measure needle-like or dendritic ones directly with an electron microscope. preferable.

The volume resistance of the powder of titanium oxide fine particles and zinc oxide fine particles is preferably 10 ⁵ to 10 ¹⁰ Ωcm.
When the volume resistance value of the powder is smaller than 10 ⁵ Ωcm, the resistance value as the undercoat layer 22 is lowered and does not function as a charge blocking layer. For example, in the case of metal compound fine particles subjected to a conductive treatment such as a tin oxide conductive layer doped with antimony, the volume resistance value of the powder is very low, 10 ⁰ Ωcm to 10 ¹ Ωcm, and this was used. The undercoat layer 22 does not function as a charge blocking layer and cannot be used because fogging and black spots (black spots) are generated in the image due to deterioration in chargeability as a photoreceptor characteristic.
Further, when the volume resistivity of the powder is increased to 10 ¹⁰ Ωcm or more and becomes equal to or more than the volume resistivity of the binder resin itself, the resistance value as the undercoat layer is too high, and the carrier generated during light irradiation This is not preferable because the transport of light is inhibited and inhibited, and the residual potential increases and the photosensitivity decreases.

  As long as the volume resistance value of the titanium oxide fine particles or zinc oxide fine particles is maintained within the above range, the surface of the fine particles should be coated with an inorganic compound such as alumina or an organic compound such as a silane coupling agent. Can do. If the metal compound fine particles used are titanium oxide fine particles or zinc oxide fine particles whose surface has not been treated, even if the coating solution for the undercoat layer is sufficiently dispersed due to the fine particles, it can be used for a long period of time or stored for a long time. Sometimes aggregation of titanium oxide fine particles or zinc oxide fine particles is inevitable. Therefore, when the undercoat layer 22 is formed, a coating film defect or coating unevenness occurs, resulting in an image defect. In addition, since the injection of charges from the conductive support 3 is likely to occur, the chargeability of the minute region is lowered and black spots are generated.

Therefore, the surface of the titanium oxide fine particles or zinc oxide fine particles is coated with various metal compounds or mixtures thereof to prevent the fine particles from agglomerating, and a coating solution for the undercoat layer having excellent dispersibility and storage stability is obtained. can get.
Furthermore, since the injection of charges from the conductive support 3 can be suppressed, an electrophotographic photosensitive member having excellent image characteristics free from black spots can be obtained. Al ₂ O ₃ , ZrO ₂ , and SiO ₂ are preferable as the metal compound that covers the surface of the titanium oxide fine particles or zinc oxide fine particles. In addition, when surface treatment is performed with both different metal compounds such as Al ₂ O ₃ or ZrO ₂ and a plurality of different materials such as Al (OH) ₃ , more excellent image characteristics can be obtained, so that a more preferable effect can be obtained. Expressed.

In addition, when the surface of titanium oxide fine particles or zinc oxide fine particles is coated with a metal compound having magnetism such as Fe ₂ O ₃ , a chemical interaction occurs with the phthalocyanine pigment contained in the photosensitive layer, and the photosensitive layer is exposed to light. It is not preferable because the body characteristics, particularly the sensitivity and chargeability, are reduced.
The surface treatment amount of Al ₂ O ₃ , ZrO ₂ , SiO ₂ or Al (OH) ₃ used as a metal compound for coating the surface of titanium oxide fine particles or zinc oxide fine particles is as compared with titanium oxide fine particles or zinc oxide fine particles. 0.1 to 20% by weight is preferred. If the treatment amount is less than 0.1% by weight, the surface of the titanium oxide fine particles or the zinc oxide fine particles cannot be sufficiently covered, so that the effect of the surface treatment is hardly exhibited. If the treatment amount exceeds 20% by weight, it is sufficiently applied as the surface treatment, and the characteristics are not changed.

The surface of the titanium oxide fine particles or zinc oxide fine particles dispersed in the undercoat layer 22 can be coated with an organic compound, and a general coupling agent can be used.
Examples of the coupling agent include silane coupling agents such as alkoxysilane compounds, silylating agents in which atoms such as halogen, nitrogen and sulfur are bonded to silicon, titanate coupling agents, aluminum coupling agents, and the like. It is done.
For example, as a silane coupling agent, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, ethyltrimethoxysilane, diethyldimethoxysilane, phenyltriethoxysilane, aminopropyltrimethoxysilane, γ- (2-aminoethyl) Aminopropylmethyldimethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, 3- (1-aminopropoxy) -3,3-dimethyl-1-propenyltrimethoxysilane, (3-acryloxypropyl) trimethoxysilane, ( Al, such as 3-acryloxypropyl) methyldimethoxysilane, (3-acryloxypropyl) dimethylmethoxysilane, N-3- (acryloxy-2-hydroxypropyl) -3-aminopropyltriethoxysilane Xysilane compounds, chlorosilanes such as methyltrichlorosilane, methyldichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane, silazanes such as hexamethyldisilazane, octamethylcyclotetrasilazane, isopropyltriisostearoyl titanate, bis (dioctyl pyrophosphate) ) And other titanate coupling agents, and aluminum coupling agents such as acetoalkoxyaluminum diisopropylate, but are not limited thereto.
In addition, when titanium oxide fine particles or zinc oxide fine particles are subjected to surface treatment with these coupling agents, or when these coupling agents are used as dispersants, one or more coupling agents are used in combination. Also good.

The surface treatment of titanium oxide fine particles or zinc oxide fine particles is roughly classified into a pretreatment method and an integral blend method, and the pretreatment methods are further classified into a wet method and a dry method. The surface treatment may be performed using any method within a range in which electrical characteristics and image defects do not occur.
Further, the metal oxide fine particles are coated on the surface with an untreated surface, Al ₂ O ₃ , ZrO ₂ , SiO ₂ or the like, or a mixture thereof or a metal compound such as Al (OH) _3, and then the above-mentioned cup. Surface treatment with a metal compound and an organic compound may be used in combination as long as the volume resistance value of the powder is maintained in the above-mentioned range, such as surface treatment with a ring agent.

The content of the metal compound fine particles in the undercoat layer is in the range of 10 to 99% by weight, preferably 30 to 99% by weight, and more preferably 35 to 95% by weight.
When the metal compound fine particle is less than 10% by weight, the sensitivity is lowered, the electric charge is accumulated in the undercoat layer, the residual potential is increased, and the repetitive characteristics under low temperature and low humidity may be remarkable.
On the other hand, when the metal compound fine particle exceeds 99% by weight, the storage stability of the coating solution for the undercoat layer is deteriorated and the metal compound fine particle is liable to settle, and the inside of the pipe of the coating apparatus 20, the coating tank 1, and the overflow tank. When used for a long time in a circulation type electrophotographic photoreceptor manufacturing apparatus that is supplied and circulated through a liquid feed pump 17 such as 10, the metal oxide fine particles are likely to be aggregated and settled, resulting in coating defects due to aggregates and the like. That is not preferable.

[Binder resin]
Examples of the binder resin contained in order to uniformly disperse and hold such metal oxide particles include polyethylene, polypropylene, polystyrene, acrylic resin, vinyl chloride resin, vinyl acetate resin, polyurethane resin, epoxy resin, and polyester. Resin, melamine resin, silicon resin, butyral resin, polyamide resin and other resin materials, copolymer resins containing two or more of these repeating units, and casein, gelatin, polyvinyl alcohol, ethyl cellulose, etc. are known Yes. Among these, alcohol-soluble polyamide resins, butyral resins, and vinyl acetate resins are preferable, and polyamide resins are particularly preferable.

  This is because the binder resin does not dissolve or swell in the solvent used when forming the photosensitive layer 24 on the undercoat layer 22, or adheres to the conductive support 3. Properties such as excellent and flexible, good affinity with the metal compound fine particles contained in the undercoat layer 22, and excellent dispersibility of the metal compound fine particles and storage stability of the dispersion Because is required.

Among polyamide resins, alcohol-soluble nylon resins are preferable. Specifically, 6-nylon, 66-nylon, 610-nylon, 11-nylon, 12-nylon and the like are copolymerized nylon, N-alkoxymethyl modified nylon, N-alkoxyethyl modified nylon. The type which chemically modified | denatured nylon is mentioned.
Further, it is particularly preferable to use a polyamide resin that is soluble in an organic solvent containing a dicarboxylic acid that is a natural product-derived fatty acid or a derivative thereof, or a diamine compound having a cyclic structure such as piperazine or isophoronediamine.

The content of the binder resin in the undercoat layer 22 is in the range of 1 to 90% by weight, preferably 1 to 70% by weight, and more preferably 5 to 65% by weight.
When the binder resin is less than 1% by weight, the storage stability of the coating solution for the undercoat layer is deteriorated, which is not preferable.
On the other hand, when the binder resin exceeds 90% by weight, the effect of the metal compound fine particles is reduced, so that the effect is lowered, and the electrical characteristics and image characteristics are deteriorated, and the repeated stability and environmental characteristics are also deteriorated. Therefore, it is not preferable.

[Organic solvent]
As the organic solvent for dissolving the binder resin used in the coating solution for the undercoat layer, a general organic solvent can be used. However, it is preferable that the binder resin is hardly soluble in the solvent for the coating solution for the photosensitive layer. When an alcohol-soluble nylon resin is used, the lower alcohol group having 1 to 4 carbon atoms and the group consisting of dichloromethane, chloroform, 1,2-dichloroethane, 1,2-dichloropropane, toluene, tetrahydrofuran, and 1,3-dioxolane are used. Selected single and mixed organic solvents can be used.

However, halogen-based solvents are not preferable because their use is in the direction of reduction or prohibition due to recent environmental problems and safety problems.
More specifically, the lower alcohol selected from the group consisting of methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, n-butyl alcohol, isobutyl alcohol, and t-butyl alcohol is used as the solvent for the coating solution for the undercoat layer. A mixed solvent with other organic solvents such as tetrahydrofuran and 1,3-dioxolane is more preferable.

3. Photosensitive layer The photosensitive layer 24 formed on the undercoat layer 22 has a function-separated type (laminated type) photosensitive layer composed of two layers of a charge generation layer 26 and a charge transport layer 27, and these are separated. Although there is a single-layer type photosensitive layer formed without a single layer, any of them may be used.

In FIG. 18, the photosensitive layer 24 is a stacked photosensitive layer (also referred to as a “function-separated photosensitive layer”) in which the charge generation layer 26 and the charge transport layer 27 are stacked in this order on the undercoat layer 22. FIG. 2 is a schematic cross-sectional view illustrating a configuration of a main part of a multilayer photoreceptor.
FIG. 19 is a schematic cross-sectional view showing a configuration of a main part of a single-layer type photosensitive member in which the photosensitive layer 24 is a single-layer type photosensitive layer composed of one layer and is laminated on the undercoat layer 22.
In the stacked photosensitive layer of FIG. 18, the charge generation layer 26 and the charge transport layer 27 may be reversed, but the stacked photosensitive layer formed in the order of FIG. 18 is more preferable.
18 is formed on the surface of the conductive support 3 with an undercoat layer 22, a charge generation layer 26 containing a charge generation material and a binder resin, and a charge transport containing a charge transport material and a binder resin. A laminated photosensitive layer 24 in which the layer 27 is laminated in this order is formed in this order.
The single-layer type photosensitive member 30 in FIG. 19 has an undercoat layer 22, a single-layer type photosensitive layer 24 containing a charge generating substance, a charge transporting substance, and a binder resin in this order on the surface of the conductive support 3. Is formed.

[Photosensitive layer of multilayer photoconductor]
The photosensitive layer 24 of the multilayer photoreceptor 30 includes a charge generation layer 26 and a charge transport layer 27. As described above, by assigning the charge generation function and the charge transport function to separate layers, the optimum material constituting each layer can be independently selected.
In the following description, a stacked type photoconductor (FIG. 18) in which the charge generation layer 26 and the charge transport layer 27 are stacked in this order will be described. They are basically the same except for the differences.
In either case of the single layer structure or the laminated structure, the photosensitive layer is a laminated layer in order that the undercoat layer 22 serves as a barrier against hole injection from the conductive support 3 and has high sensitivity and high durability. The photosensitive layer 24 of the type photoreceptor 30 and the photosensitive layer 24 of the single-layer type photoreceptor 30 described later are preferably negatively charged.

[Charge generation layer 26]
The charge generation layer 26 is mainly composed of a charge generation material having a charge generation capability of generating charges by absorbing irradiated light, and optionally contains a known additive and a binder resin (binder).
As the charge generation material, a compound used in this field can be used.
Specifically, an azo pigment (having a carbazole skeleton, a styryl stilbene skeleton, a triphenylamine skeleton, a dibenzothiophene skeleton, an oxadiazole skeleton, a fluorenone skeleton, a bis-stilbene skeleton, a distyryl oxadiazole skeleton, or a distyryl carbazole skeleton. , Monoazo pigments, bisazo pigments, trisazo pigments, etc.), perylene pigments (peryleneimide, perylene acid anhydride, etc.), polycyclic quinone pigments (quinacridone, anthraquinone, pyrenequinone, etc.), phthalocyanine pigments (metal phthalocyanine, no Metal phthalocyanine, halogenated metal-free phthalocyanine, etc.), indigo pigments (indigo, thioindigo, etc.), squarylium dyes, azurenium dyes, thiopyrylium dyes, pyrylium salts, triphenylmethane Organic pigments or dyes such as dyes, further selenium, inorganic materials such as amorphous silicon. These charge generating materials can be used alone or in combination of two or more.

The photoreceptor 30 that forms an image by a reversal development process using a light source such as a laser beam or an LED is required to have sensitivity in a long wavelength range of 620 to 800 nm.
Among the above charge generating materials, phthalocyanine pigments and trisazo pigments are particularly preferable because they have durability and high sensitivity.
As the metal used in the metal phthalocyanine pigment, those having an oxidation state of zero, and halides and oxides such as chlorides and bromides thereof are used. Preferred metals include Cu, Ni, Mg, Pb, V, Pd, Co, Nb, Al, Sn, Zn, Ca, In, Ga, Fe, Ge, Ti, Cr, and the like.
Various methods for producing these phthalocyanine pigments have been proposed, but are not particularly limited, and after being pigmented, various purifications and treatments for converting crystal forms, such as dispersion treatments in various organic solvents, are performed. May be.

As the charge generation material, a metal having an amorphous type or a crystal type such as α type, β type, γ type, δ type, ε type, χ type, τ type or the like can be used.
The charge generation layer 26 is a chemical sensitizer, an optical sensitizer, an antioxidant, an ultraviolet absorber, a dispersion stabilizer, a sensitizer, a leveling agent, and a plasticizer as long as preferable characteristics of the present invention are not impaired. In addition, an appropriate amount of one or more known additives selected from fine particles of inorganic compounds or organic compounds may be contained. These additives may be contained in the charge transport layer 27 described later, or may be contained in both the charge generation layer 26 and the charge transport layer 27.

The chemical sensitizer and the optical sensitizer improve the sensitivity of the photoreceptor 30, suppress an increase in residual potential and fatigue due to repeated use, and improve electrical durability.
Examples of chemical sensitizers include acid anhydrides such as succinic anhydride, maleic anhydride, phthalic anhydride, and 4-chloronaphthalic anhydride; cyano compounds such as tetracyanoethylene and terephthalmalondinitrile, 4-nitrobenzaldehyde, and the like. Aldehydes; anthraquinones such as anthraquinone and 1-nitroanthraquinone; polycyclic or heterocyclic nitro compounds such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitrofluorenone; diphenoquinone compounds Examples thereof include electron-withdrawing materials and those obtained by polymerizing these electron-withdrawing materials.

  Examples of the optical sensitizer include xanthene dyes, quinoline pigments, organic photoconductive compounds such as copper phthalocyanine, triphenylmethane dyes represented by methyl violet, crystal violet, knight blue and victoria blue; erythrosin, Acridine dyes typified by rhodamine B, rhodamine 3R, acridine orange and frappeocin; thiazine dyes typified by methylene blue and methylene green; oxazine dyes typified by capri blue and meldra blue; cyanine dyes; styryl dyes; Examples include pyrylium salt dyes and thiopyrylium salt dyes.

Antioxidants can maintain sensitivity stability over a long period of time.
Antioxidants include phenolic antioxidants such as hindered phenols such as 2,6-di-t-butyl-4-methylphenol (2,6-di-t-butyl-p-cresol: BHT). , Amine antioxidants such as hindered amines, vitamin E, hydroquinone, paraphenylenediamine, arylalkanes and derivatives thereof, organic sulfur compounds, organic phosphorus compounds, etc., and these may be used alone or in combination of two or more. Can be used.
The addition amount of the antioxidant is preferably from 0.1 to 40 parts by weight, particularly preferably from 0.5 to 15 parts by weight, based on 100 parts by weight of the charge generation material.
If the added amount of the antioxidant is less than 0.1 parts by weight, there is a possibility that sufficient effects cannot be obtained for improving the stability of the coating solution and improving the durability of the photoreceptor. On the other hand, if the amount of the antioxidant added exceeds 40 parts by weight, the photoreceptor characteristics may be adversely affected.

Leveling agents and plasticizers can improve film formability, flexibility and surface smoothness.
Examples of the leveling agent include a silicone leveling agent.
Examples of the plasticizer include dibasic acid esters such as phthalate esters, fatty acid esters, phosphate esters, chlorinated paraffins, and epoxy type plasticizers.
Fine particles of an inorganic compound or an organic compound can enhance mechanical strength and improve electrical characteristics. Examples of such fine particles include the fine particles exemplified in the undercoat layer described above.
The basic structure of the above titanyl phthalocyanine has the following general formula:

(Wherein, X _{1 to} X ₄ represent a halogen atom, C _{1 to} C ₄ alkyl or an alkoxy group, and k, l, m and n are integers of 0 to 4).

Halogen atom described above is fluorine, chlorine, bromine or iodine atom, C ₁ -C ₄ alkyl groups mentioned are methyl, ethyl, n- propyl, isopropyl, be n- butyl, isobutyl or t- butyl group And the C ₁ -C ₄ alkoxy group is a methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy or t-butoxy group.

  The method for synthesizing titanyl phthalocyanine may be any of the known methods described in Moser and Thomas “Phthalocyanine Compounds”, Reinhold Publishing Corp., New York, 1963. For example, dichlorotitanium phthalocyanine can be obtained in good yield by heating and melting o-phthalodinitrile and titanium tetrachloride or by heating in the presence of an organic solvent such as α-chloronaphthalene. Furthermore, titanyl phthalocyanine is obtained by hydrolyzing the dichlorotitanium phthalocyanine with a base or water. The obtained titanyl phthalocyanine may contain a phthalocyanine derivative in which the hydrogen atom of the benzene ring is substituted with a substituent such as chlorine, fluorine, nitro group, cyano group or sulfone group.

Such a titanyl phthalocyanine composition can be treated with a water-immiscible organic solvent such as dichloroethane in the presence of water.
As a method of treating titanyl phthalocyanine with an organic solvent having a non-affinity with water in the presence of water, a method in which titanyl phthalocyanine is swollen with water and treated with an organic solvent, or water is removed without performing a swelling treatment. Examples thereof include, but are not limited to, a method of adding titanyl phthalocyanine powder therein, and adding titanyl phthalocyanine powder therein.
Examples of methods for swelling titanyl phthalocyanine with water include, for example, a method in which titanyl phthalocyanine is dissolved in sulfuric acid and precipitated in water to form a wet paste, or stirring / dispersing such as a homomixer, paint mixer, ball mill, or side mill Although the method etc. which swell a titanyl phthalocyanine with water using an apparatus and make it into a wet paste form are mentioned, It is not limited to this.

Moreover, the titanyl phthalocyanine composition obtained by hydrolysis can be milled with sufficient stirring or mechanical strain.
As a device used in this treatment, a homomixer, a paint mixer, a disperser, an agitator, a ball mill, a side mill, an attritor, an ultrasonic dispersion device, or the like can be used in addition to a general stirring device. After the treatment, it is filtered, washed and isolated with methanol, ethanol, water or the like.

  The titanyl phthalocyanine thus obtained exhibits excellent characteristics as a charge generation material for an electrophotographic photoreceptor. In addition to the above titanyl phthalocyanine, other charge generation materials may be used in combination. Examples of such a charge generation material include α-type, β-type, Y-type, amorphous titanyl phthalocyanine having a different crystal form from the above-mentioned titanyl phthalocyanine, or other phthalocyanines, azo pigments, anthraquinone pigments, perylene. Examples thereof include pigments, polycyclic quinone pigments, and squalium pigments.

  The charge generation layer 26 using these phthalocyanine pigments includes a method of forming a charge generation material, particularly a phthalocyanine pigment by vacuum deposition, and a method of forming a film by mixing and dispersing a binder resin and an organic solvent. However, the pulverization process may be performed in advance by a pulverizer before the mixing and dispersing process. As the pulverizer used in the pulverizer, there are methods using a ball mill, a sand mill, an attritor, a vibration mill, an ultrasonic disperser, etc., but the pigment crystal type that affects the sensitivity of the electrophotographic photoreceptor 30, particularly In order to convert the crystal system of the phthalocyanine pigment into a predetermined crystal form or maintain the crystal form, various dispersers may be used.

  The binder resin used in the coating solution for the photosensitive layer includes melamine resin, epoxy resin, silicon resin, polyurethane resin, acrylic resin, polycarbonate resin, polyarylate resin, phenoxy resin, butyral resin, and two or more repeating units. Insulating resins such as vinyl chloride-vinyl acetate copolymer resin and acrylonitrile-styrene copolymer resin can be mentioned, but are not limited to these and are generally used. All the resins can be used alone or in admixture of two or more.

  Solvents for dissolving these resins include halogenated hydrocarbons such as methylene chloride and ethane chloride, ketones such as acetone, methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, tetrahydrofuran, dioxane and the like. Ethers, aromatic hydrocarbons such as benzene, toluene and xylene, aprotic polar solvents such as N, N-dimethylformamide and N, N-dimethylacetamide, or mixed solvents thereof can be used. The blending ratio of the phthalocyanine pigment and the binder resin is preferably in the range of 10% to 99% by weight of the phthalocyanine pigment. If the amount is less than this range, the sensitivity is lowered. If the amount is larger, not only the durability is lowered, but also the dispersibility is lowered and coarse particles are increased, so that image defects, particularly black spots are increased.

When manufacturing the coating solution for the charge generation layer, the above-mentioned phthalocyanine pigment, binder resin, and organic solvent are mixed and dispersed. However, as a dispersion condition, impurities are not mixed due to wear of containers and dispersion media used. Appropriate dispersion conditions are selected.
It is important that the phthalocyanine pigment contained in the dispersion obtained as described above is dispersed to primary particles and / or aggregated particle diameters of 3 μm or less.
In the electrophotographic photosensitive member 30 obtained if the primary particles and / or the aggregated particle diameter thereof is larger than 3 μm, black spots are very generated on a white background during reversal development. Therefore, when manufacturing the coating solution for the charge generation layer by various dispersing machines, the dispersion conditions are optimized and the phthalocyanine pigment particles are dispersed to 3 μm or less, more preferably 0.5 μm or less in median diameter and 3 μm or less in mode diameter. It is preferable not to contain particles larger than this.

Because of its chemical structure, phthalocyanine pigment particles require relatively strong dispersion conditions and a long dispersion time in order to make fine particles, and further dispersion is inefficient in terms of cost and wear of the dispersion media. Impurities are inevitably mixed.
Further, since the crystal form of the phthalocyanine pigment particles changes due to an organic solvent at the time of dispersion, heat, impact due to dispersion, or the like, there is a problem that the sensitivity of the photoreceptor is greatly reduced. Therefore, it is not preferable to reduce the particle diameter of the phthalocyanine pigment so that the median diameter is 0.01 μm or less and the mode diameter is 0.1 μm or less.

In addition, when particles larger than 3 μm are contained in the phthalocyanine pigment particles in the dispersed coating liquid, primary particles and / or aggregated particles larger than 3 μm can be removed by performing a filtration treatment. . As the material of the filter used for the filtration treatment, those commonly used are used as long as they do not swell or dissolve in the organic solvent used for dispersion, but preferably made of Teflon (registered trademark) having a uniform pore size. A membrane filter is good. Further, coarse particles and aggregates may be removed by centrifugation.
The charge generation layer formed using the thus obtained charge generation layer coating solution is preferably applied to a thickness of 0.05 μm to 10 μm, more preferably 0.08 μm to 5 μm.

In the configuration of the undercoat layer 22 and the photosensitive layer 24, the sensitivity characteristics are improved when the thickness of the charge generation layer 26 is increased. However, a small black spot is generated on a white background due to the disappearance of the surface charge in the minute region. There was an adverse effect of defects.
On the other hand, if the thickness of the undercoat layer 22 is reduced, the sensitivity is lowered, so that a practical film thickness for reducing both image defects and improving electrical characteristics and production stability is limited. .

If the thickness of the charge generation layer is thinner than the above-mentioned thickness, not only the sensitivity is lowered, but also the phthalocyanine pigment needs to be dispersed until it becomes very small.
Further, if the charge generation layer is thicker than the above-mentioned film thickness, a certain sensitivity is exhibited, but it is not preferable in terms of cost, and it is not preferable because it is difficult to apply uniformly.

  As described above, the coating method for uniformly forming the charge generation layer 26, which greatly affects the electrical characteristics of the electrophotographic photosensitive member 30, particularly the photosensitive member sensitivity, without uneven coating, is the same as the formation of the undercoat layer 22. Applying the flow of the coating solution uniformly and undisturbed by providing a rectifying groove 9 on the inner wall of the coating tank 1 shown in the invention, and further providing cuts at equal intervals on the circumference of the upper opening 7 of the coating tank 1 The charge generation layer 26 without defects can be formed.

[Charge transport layer 27]
As a method for producing the charge transport layer 27 provided on the charge generation layer 26, a charge transport coating solution in which a charge transport material is dissolved in a binder resin solution is prepared, and this is applied to form a film. The method is common.
Known charge transport materials contained in the charge transport layer include hydrazone compounds, pyrazoline compounds, triphenylamine compounds, triphenylmethane compounds, stilbene compounds, oxadiazole compounds, etc. Or it is also possible to use 2 or more types together.

As the binder resin, one or a mixture of two or more resins for the charge generation layer can be used. As a method for producing the charge transport layer 27, a method similar to that for the undercoat layer 22 is used.
The film thickness of the charge transport layer 27 is preferably in the range of 5 μm to 50 μm, more preferably 10 μm to 40 μm.

[Photosensitive layer of single layer type photoreceptor]
The single-layer type photosensitive layer 24 contains a charge generation material, a charge transport material, and a binder resin (binder) as main components.
The single-layer type photosensitive layer 24 may contain an appropriate amount of the same additive as that contained in the charge generation layer 26 as necessary.
The single-layer type photosensitive layer 24 is prepared by dissolving and / or dispersing a charge generation material, a charge transport material and, if necessary, other additives in an appropriate organic solvent to prepare a coating solution for forming a single-layer type photosensitive layer, This coating solution can be formed by coating the surface of the undercoat layer 22 formed on the conductive support 3 and then drying to remove the organic solvent.
Other steps and conditions are in accordance with the formation of the charge generation layer 26 and the charge transport layer 27.

The film thickness of the single-layer type photosensitive layer 24 is not particularly limited, but is preferably 5 to 50 μm, particularly preferably 10 to 40 μm.
If the film thickness of the single-layer type photosensitive layer 24 is less than 5 μm, the charge holding ability of the surface of the photoreceptor 30 may be reduced. If the film thickness of the single-layer type photosensitive layer 24 exceeds 50 μm, the productivity is increased. May decrease.

  In addition, at least one kind of electron-accepting substance can be added to the photosensitive layer 24 for the purpose of improving sensitivity, reducing residual potential and fatigue during repeated use. For example, quinone compounds such as parabenzoquinone, chloranil, tetrachloro 1,2-benzoquinone, hydroquinone, 2,6-dimethylbenzoquinone, methyl 1,4-benzoquinone, α-naphthoquinone, β-naphthoquinone, 2,4,7- Nitro compounds such as trinitro-9-fluorenone, 1,3,6,8-tetranitrocarbazole, p-nitrobenzophenone, 2,4,5,7-tetranitro-9-fluorenone, 2-nitrofluorenone, tetracyanoethylene, 7,7,8,8-tetracyanoquinodimethane, 4- (P-nitrobenzoyloxy) -2 ′, 2′-dicyanovinylbenzene, 4- (m-nitrobenzoyloxy) -2 ′, 2′- And cyano compounds such as dicyanovinylbenzene.

Of these, fluorenone-based compounds, quinone-based compounds, and benzene derivatives having electron-withdrawing substituents such as Cl, CN, and NO ₂ are particularly preferable. Further, ultraviolet absorbers and antioxidants such as benzoic acid, stilbene compounds and derivatives thereof, nitrogen-containing compounds such as triazole compounds, imidazole compounds, oxadiazole compounds, thiazole compounds, and derivatives thereof may be contained. it can.

4). Overcoat Layer The photoreceptor 30 may have an overcoat layer 29 on the surface of the photosensitive layer 24 of the multilayer photoreceptor and the photosensitive layer 24 of the single-layer photoreceptor. For example, an overcoat layer 29 can be provided on the photosensitive layer 24 as shown in FIG.
The overcoat layer 29 has a function of improving the abrasion of the photosensitive layer 24 and preventing chemical adverse effects caused by ozone, nitrogen oxides, and the like.

For the overcoat layer 29, a thermoplastic resin, light, or a thermosetting resin can be used. In addition, the overcoat layer 29 may contain an ultraviolet ray inhibitor, an antioxidant, an inorganic material such as a metal oxide, an organometallic compound, an electron accepting substance, or the like.
The overcoat layer 29 is prepared by, for example, preparing a coating solution for forming an overcoat layer by dissolving or dispersing a binder resin and, if necessary, an additive such as an antioxidant or an ultraviolet absorber in a suitable organic solvent. It can be formed by applying a coating solution for forming a coat layer on the surface of the single-layer type photosensitive layer 24 or the laminated type photosensitive layer 24 and removing the organic solvent by drying.
Other steps and conditions are in accordance with the formation of the charge generation layer 26.

The thickness of the overcoat layer 29 is not particularly limited, but is preferably 0.5 to 10 μm, and particularly preferably 1 to 5 μm. If the film thickness of the overcoat layer 29 is less than 0.5 μm, the surface of the photoreceptor 30 may be inferior in scratch resistance and durability may be insufficient. Conversely, if it exceeds 10 μm, the resolution of the photoreceptor 30 may be reduced. May decrease.
The photosensitive layer 24 and the overcoat layer 29 are mixed with a plasticizer such as a dibasic acid ester, a fatty acid ester, a phosphoric acid ester, a phthalic acid ester or chlorinated paraffin as required, so that processability and flexibility are improved. To improve mechanical properties, and a leveling agent such as silicone resin can also be used.

In particular, in order to improve wear resistance, metal oxide fine particles and fluorine compound fine particles may be dispersed in the same manner as in the case of the undercoat layer 22, and such a dispersion is applied by using the coating apparatus 20 of the present invention. There is no unevenness and a uniform layer can be formed.
The electrophotographic photoreceptor 30 of the present invention can be used in various printers and electrophotographic plate making systems using an electrophotographic copying machine, a laser, a light emitting diode (LED), or the like as a light source.

Image Forming Apparatus The present embodiment also provides an image forming apparatus 45 equipped with the electrophotographic photosensitive member 30 of the present embodiment.
FIG. 21 is a schematic cross-sectional view of the image forming apparatus of the present embodiment.

The image forming apparatus 45 according to the present embodiment includes the photoconductor 30 according to the present embodiment, a charging unit 34 that charges the photoconductor 30, and an exposure unit 38 that exposes the charged photoconductor 30 to form an electrostatic latent image. Developing means 35 for developing the electrostatic latent image formed by exposure to form a toner image; transfer means 36 for transferring the toner image formed by development onto a recording medium; and At least fixing means 41 for fixing the toner image on the recording material to form an image can be provided.
The image forming apparatus 45 of the present embodiment will be described with reference to the drawings, but is not limited to the following description.

  The image forming apparatus 20 in FIG. 21 includes a photoconductor 30, a charging unit (charger) 34, an exposure unit 38, a developing unit (developing unit) 35, a transfer unit (transfer unit) 36, and the like. It includes a cleaning means (cleaner) 37, a fixing means (fixing device) 41, and a charge eliminating means (not shown, provided alongside the cleaning means 37). Reference numeral 40 denotes a transfer sheet.

  The photosensitive member 30 is rotatably supported by the main body of the image forming apparatus 45 (not shown), and is driven to rotate around the rotation axis 32 in the direction of the arrow 33 by a driving unit (not shown). The driving means includes, for example, an electric motor and a reduction gear, and transmits the driving force to the conductive support 3 constituting the core of the photoconductor 30, thereby rotating the photoconductor 30 at a predetermined peripheral speed. Let The charger 34, the exposure unit 38, the developing unit 35, the transfer unit 36, and the cleaner 37 are arranged in this order along the outer peripheral surface of the photoconductor 30 from the upstream side in the rotation direction of the photoconductor 30 indicated by the arrow 33. It is provided toward the side.

  The charger 34 is a charging unit that charges the outer peripheral surface of the photoconductor 30 to a predetermined potential. Specifically, for example, the charger 34 is realized by a contact-type charging roller 34a, a charging brush, or a charger wire such as a corotron or a scorotron. Reference numeral 34b indicates a bias power source.

  The exposure unit 38 includes, for example, a semiconductor laser as a light source, and irradiates a laser beam 38 a output from the light source between the charger 34 and the developing unit 35 of the photoconductor 30, thereby charging the photoconductor 30. The outer peripheral surface is exposed according to image information. The light 38 a is repeatedly scanned in the main scanning direction in the direction in which the rotation axis 32 of the photoconductor 30 extends, and accordingly, electrostatic latent images are sequentially formed on the surface of the photoconductor 30.

  The developing unit 35 is a developing unit that develops an electrostatic latent image formed on the surface of the photoconductor 30 by exposure with a developer. The developing unit 35 is provided facing the photoconductor 30 and applies toner to the outer peripheral surface of the photoconductor 30. A developing roller 35a to be supplied and a casing 35b that supports the developing roller 35a so as to be rotatable about a rotation axis parallel to the rotation axis 32 of the photosensitive member 30 and accommodates a developer containing toner in the internal space thereof.

  The transfer unit 26 supplies a toner image, which is a visible image formed on the outer peripheral surface of the photoconductor 30 by development, between the photoconductor 30 and the transfer unit 36 from the direction of the arrow 39 by a conveying unit (not shown). It is a transfer means for transferring onto the transfer paper 40 which is a recording medium. The transfer unit 26 is, for example, a non-contact type transfer unit that includes a charging unit and transfers a toner image onto the transfer paper 40 by applying a charge having a polarity opposite to that of the toner to the transfer paper 40.

  The cleaner 37 is a cleaning unit that removes and collects toner remaining on the outer peripheral surface of the photoconductor 30 after the transfer operation by the transfer device 36, and includes a cleaning blade 37 a that peels off toner remaining on the outer peripheral surface of the photoconductor 30, and a cleaning device. A recovery casing 37b for storing the toner separated by the blade 37a. The cleaner 37 is provided together with a charge eliminating lamp (not shown).

  Further, the image forming apparatus 45 is provided with a fixing device 41 which is a fixing means for fixing the transferred image on the downstream side where the transfer paper 40 that has passed between the photoreceptor 30 and the transfer device 36 is conveyed. . The fixing device 41 includes a heating roller 41a having a heating unit (not shown), and a pressure roller 41b that is provided to face the heating roller 41a and is pressed by the heating roller 41a to form a contact portion.

  The image forming operation by the image forming apparatus 45 is performed as follows. First, when the photosensitive member 30 is rotationally driven in the direction of the arrow 33 by the driving unit, the photosensitive member is provided by the charger 34 provided on the upstream side of the image forming point of the light 38a by the exposure unit 38 in the rotational direction of the photosensitive member 30. 30 surfaces are uniformly charged to a predetermined positive or negative potential.

  Next, light 38 a corresponding to image information is irradiated from the exposure unit 38 to the surface of the photoreceptor 30. With this exposure, the surface charge of the portion irradiated with the light 38a is removed from the photosensitive member 30, and a difference occurs between the surface potential of the portion irradiated with the light 38a and the surface potential of the portion not irradiated with the light 38a. An electrostatic latent image is formed.

Next, toner is supplied to the surface of the photosensitive member 30 on which the electrostatic latent image is formed from a developing unit 35 provided on the downstream side in the rotation direction of the photosensitive member 30 with respect to the image formation point of the light 38a by the exposure unit 38. The electrostatic latent image is developed to form a toner image.
In synchronization with the exposure of the photoconductor 30, the transfer paper 40 is supplied between the photoconductor 30 and the transfer device 36. The transfer device 36 applies a charge having the opposite polarity to the toner to the supplied transfer paper 40, and the toner image formed on the surface of the photoreceptor 30 is transferred onto the transfer paper 40.

  Next, the transfer paper 40 onto which the toner image has been transferred is conveyed to the fixing device 41 by the conveying means, and is heated and pressurized when passing through the contact portion between the heating roller 41a and the pressure roller 41b of the fixing device 41. The toner image is fixed on the transfer paper 40 and becomes a robust image. The transfer paper 40 on which the image is formed in this way is discharged to the outside of the image forming apparatus 45 by the conveying means.

On the other hand, the toner remaining on the surface of the photoconductor 30 even after the transfer of the toner image by the transfer device 36 is separated from the surface of the photoconductor 30 by the cleaner 37 and collected. The charge on the surface of the photoconductor 30 from which the toner has been removed in this manner is removed by the light from the static elimination lamp, and the electrostatic latent image on the surface of the photoconductor 30 disappears. Thereafter, the photoconductor 30 is further driven to rotate, and a series of operations starting from charging again is repeated to continuously form images.
Further, the image forming apparatus is not equipped with a cleaning unit such as a cleaner 37 that removes and collects toner remaining on the photoconductor 30 depending on the model, and a neutralizing unit that neutralizes the surface charge remaining on the photoconductor 30. There may be.

Electrophotographic photoreceptor production experiment An experiment for producing an electrophotographic photoreceptor using the coating apparatus of the present invention was conducted. Table 1 summarizes the types of electrophotographic photoreceptors produced in this experiment and the types of coating tanks used in the production.
All of the coating tanks included in the coating apparatus used in this experiment had an inner diameter of 70 mm and a depth of 360 mm. The type A rectifying groove 9 provided on the inner surface of the coating tank is a rectifying groove having a shape as shown in FIG. 9 and has a width of 10 mm and a depth of 5 mm. The type B rectifying groove 9 is a rectifying groove having a shape as shown in FIG. 10 and has a width of 10 mm and a depth of 5 mm. The type C rectifying groove 9 is a rectifying groove having a shape as shown in FIG. 11 and has a width of 10 mm and a depth of 5 mm. Moreover, the rectification | straightening groove | channel provided in the application tank was provided at equal intervals as shown to FIGS.

1. Example 1
A single layer type electrophotographic photosensitive member as shown in FIG. 19 was produced using the coating apparatus of the present invention. In this photoreceptor, as shown in FIG. 19, an undercoat layer 22 is formed on the conductive support 3, and a photosensitive layer 24 containing a charge generation material and a charge transport material is formed thereon. ing. Moreover, in Example 1, the application | coating provided with the application tank 1 by which the linear rectification | straightening groove | channel 9 which has a bottom and a side wall like FIGS. 2-5 and FIG. 9 (a) was provided in the inner surface at equal intervals. The undercoat layer 22 and the photosensitive layer 24 were formed using the apparatus 20. In addition, the outflow groove | channel 8 as shown in FIGS. 2-5 and FIG. 9 (a) is not formed in the coating tank 1 used in Example 1. FIG.

[Preparation of coating solution for undercoat layer]
A coating solution for the undercoat layer 22 was prepared.
First, 8 parts by weight of titanium oxide (Al (OH) ₃ , SiO ₂ surface treatment, granular, manufactured by Teika Co., Ltd., product name: MT-500SA) in a 100 L stainless steel stirring tank, polyamide resin (Arkema) Product, product name: M1276), 2 parts by weight of methanol, 50 parts by weight of methanol, 50 parts by weight of tetrahydrofuran, and a stirring motor equipped with stirring blades while heating the stainless steel container so that the liquid temperature is 40 ° C The mixed solution was stirred for 2 hours at 200 rpm to dissolve the resin, thereby obtaining a resin solution of the coating solution for the undercoat layer.

  Into a cylinder of a horizontal bead mill (manufactured by Shinmaru Enterprises Co., Ltd., model: KD-20B, cylinder volume: 16.5 L), zirconia beads having a diameter of 0.5 mm as a dispersion medium were charged up to 80% of the cylinder volume. Next, the obtained resin solution was fed from the stirring tank to the horizontal bead mill via the diaphragm pump, and the circulation of feeding the solution again to the stirring tank was continued for 30 hours at a flow rate of 3.3 L / min. 80 kg of the coating solution for the draw layer was prepared.

[Formation of undercoat layer]
Two linear straightening grooves 9 (type A) having bottom and side walls as shown in FIGS. 2 to 5 and FIG. 9A are provided on the inner surface at equal intervals. A cylindrical conductive material made of aluminum having a diameter of 30 mm and a total length of 345 mm while supplying the coating liquid for the undercoat layer to the coating tank 1 at a flow rate of 2 L / min so that the coating liquid overflows when the coating tank 1 is filled and pulled up. The support 3 is immersed in the coating solution for the undercoat layer in the coating tank 1, and the cylindrical conductive support 3 soaked in the coating layer 1 is pulled up from the coating solution for the undercoat layer. An undercoat layer coating solution was applied on the surface. The obtained coating film was dried with hot air at a temperature of 100 ° C. for 30 minutes to form an undercoat layer 22 having a dry film thickness of 1.0 μm.

[Preparation of coating solution for photosensitive layer]
A coating solution for the photosensitive layer 24 was prepared.
In a stirring tank, 20 parts by weight of τ-type metal-free phthalocyanine Liophoton TPA-891 (manufactured by Toyo Ink Mfg. Co., Ltd.), 20 parts by weight of polycarbonate resin Z-400 (manufactured by Mitsubishi Gas Chemical Co., Inc.), hydrazone system of the following formula (II) 20 parts by weight of the compound, 20 parts by weight of the diphenoquinone compound of the following formula (III) and 100 parts by weight of tetrahydrofuran were mixed to obtain a mixed solution. Thereafter, in the same manner as the coating liquid for the undercoat layer, the dispersion medium has a diameter of 0.2 mm as a dispersion medium in a cylinder of a horizontal disperser (manufactured by Shinmaru Enterprises Co., Ltd., model: Dinomill KLD pilot type, cylinder volume: 1.4 L). Zirconia beads are charged up to 80% of the cylinder volume, and the resulting mixture is sent from the stirring tank to the horizontal disperser. Then, the dispersion is transferred again to the stirring tank and the dispersion process is repeated. Then, 80 kg of photosensitive layer coating solution was prepared.

[Formation of photosensitive layer]
Two linear straightening grooves 9 (type A) having bottom and side walls as shown in FIGS. 2 to 5 and FIG. 9A were provided on the inner surface at equal intervals in the obtained photosensitive layer coating solution. Applying the conductive support 3 on which the undercoat layer 22 is formed while supplying the coating solution for the photosensitive layer to the coating bath 1 at a flow rate of 2 L / min so that the coating solution overflows when filling and coating the coating bath 1. The photosensitive layer coating solution was applied onto the undercoat layer 22 by immersing it in the photosensitive layer coating solution in the tank 1 and lifting the immersed conductive support 3 from the photosensitive layer coating solution. Thereafter, hot air drying was performed at 100 ° C. for 1 hour to provide a photosensitive layer 24 having a dry film thickness of 20 μm, and a single-layer electrophotographic photosensitive member 30 shown in FIG. 19 was produced.

2. Example 2
A function-separated electrophotographic photoreceptor (laminated photoreceptor) as shown in FIG. 18 was produced using the coating apparatus of the present invention. In this photoreceptor, as shown in FIG. 18, the undercoat layer 22 is formed on the conductive support 3, and the photosensitive layer 24 including the charge generation layer 26 and the charge transport layer 27 is formed thereon. ing. The charge generation layer 26 contains a charge generation material, and the charge transport layer 27 contains a charge transport material. Moreover, in Example 2, the application | coating provided with the application tank 1 by which the linear rectification | straightening groove | channel 9 which has a bottom and a side wall like FIGS. 2-5 and FIG. An undercoat layer 22, a charge generation layer 26 and a charge transport layer 27 were formed using the device 20. In addition, the outflow groove 8 as shown in FIGS. 2 to 5 and FIG. 9A is not formed in the coating tank 1 used in Example 2.

[Formation of undercoat layer]
An undercoat layer coating solution similar to that in Example 1 is applied on the surface of the cylindrical conductive support 3 similar to that in Example 1 in the same manner as in Example 1, and the resulting coating film is heated to a temperature. The undercoating layer 22 having a dry film thickness of 1.0 μm was formed by drying with hot air at 100 ° C. for 30 minutes.

[Preparation of coating solution for charge generation layer]
A coating solution for charge generation layer was prepared.
In a stirring tank, 2 parts by weight of τ-type metal-free phthalocyanine, Riophoton TPA-891 (manufactured by Toyo Ink Co., Ltd.), and 2 weights of vinyl chloride-vinyl acetate-maleic acid copolymer resin SOLBIN M (manufactured by Nissin Chemical Industry Co., Ltd.) Part and 100 parts by weight of methyl ethyl ketone were mixed to obtain a mixed solution. After that, in the same manner as the coating solution for the undercoat layer, 0.2 mm in diameter as a dispersion medium in the cylinder of a horizontal disperser (manufactured by Shinmaru Enterprises Co., Ltd., model: dyno mill, KLD pilot type, cylinder volume: 1.4 L) Dispersion treatment is repeated so that zirconia beads of up to 80% of the cylinder volume are fed, and the resulting mixture is fed from the stirring tank to the horizontal disperser, and then the dispersion is transferred to the stirring tank again to perform the dispersion treatment again. Then, 80 kg of a coating solution for forming a charge generation layer was prepared.

[Formation of charge generation layer]
The obtained coating solution for charge generation layer is provided with two straight rectifying grooves 9 (type A) having bottom and side walls as shown in FIGS. 2 to 5 and FIG. The conductive support 3 formed with the undercoat layer 22 while supplying the coating liquid for the charge generation layer to the coating tank 1 at a flow rate of 20 L / min so that the coating liquid overflows when the coating tank 1 is filled and pulled up. Is immersed in the charge generation layer coating solution in the coating tank 1 and the immersed conductive support 3 is pulled up from the charge generation layer coating solution, whereby the charge generation layer coating solution is applied onto the undercoat layer 22. Applied. Thereafter, it was naturally dried to form a charge generation layer 26 having a thickness of 0.8 μm.

[Preparation of coating solution for charge transport layer]
A coating solution for charge transport layer was prepared.
8 parts by weight of enamine compound of the following formula (IV), 10 parts by weight of polycarbonate resin / PCZ-400 (manufactured by Mitsubishi Gas Chemical Company), 0.002 parts by weight of silicon oil / KF50 (manufactured by Shin-Etsu Chemical Co., Ltd.), tetrahydrofuran Was mixed, stirred and dissolved to prepare 80 kg of a charge transport layer coating solution.

[Formation of charge transport layer]
The obtained coating liquid for the charge transport layer is provided with two straight rectifying grooves 9 (type A) having bottom and side walls as shown in FIGS. 2 to 5 and FIG. The conductive support 3 on which the charge generation layer 26 is formed while supplying the coating liquid for the charge transport layer to the coating tank 1 at a flow rate of 2 L / min so that the coating liquid overflows when filling and coating the coating tank 1. Is immersed in the charge transport layer coating liquid in the coating tank 1 and the immersed conductive support 3 is pulled up from the charge transport layer coating liquid, whereby the charge transport layer coating liquid is formed on the charge generation layer 26. Applied. Then, it dried at 130 degreeC for 1 hour, and formed the charge generation layer with a film thickness of 25 micrometers.
In this way, a multilayer electrophotographic photosensitive member 30 shown in FIG. 18 was produced.

3. Comparative Example 1
The same as in Example 1, except that the undercoat layer coating solution and the photosensitive layer coating solution used in Example 1 were each used in a cylindrical shape without a rectifying groove on the inner wall of the coating tank. Then, the undercoat layer 22 and the photosensitive layer 24 were formed, and a single layer type electrophotographic photosensitive member 30 shown in FIG. 19 was produced.

4). Comparative Example 2
The undercoat layer coating solution, charge generation layer coating solution, and charge transport layer coating solution used in Example 2 were used, except that a cylindrical one without a rectifying groove provided on the inner wall of the coating tank 1 was used. In the same manner as in Example 2, an undercoat layer 22, a charge generation layer 26, and a charge transport layer 27 were formed to produce a multilayer electrophotographic photoreceptor 30 shown in FIG.

5. Examples 3-10
In Examples 3 to 10, the shape of the rectifying groove 9 on the inner wall of the coating tank 1 is the type A shown in FIG. 9, the type B shown in FIG. 10, or the type C shown in FIG. A multilayer electrophotographic photosensitive member was produced in the same manner as in Example 2 except that the number of rectifying grooves 9 on the inner wall of the tank 1 was summarized in Table 1.

6). Examples 11-13
In Examples 11 to 13, the shape of the rectifying groove 9 on the inner wall of the coating tank 1 is the type A shown in FIG. 9, the type B shown in FIG. 10, or the type C shown in FIG. The same as in Example 2 except that the number of the rectifying grooves 9 on the inner wall of the tank 1 was two and the coating tank 1 was provided with an outflow groove 8 having a width of 5 mm and a depth of 2 mm at the opening end of the coating tank. A laminated electrophotographic photosensitive member was produced. In this embodiment, the outflow groove 8 is provided so as to be connected to the rectifying groove 9 as shown in FIGS.

7). Reference Examples 1-3
In Reference Examples 1 to 3, the shape of the rectifying groove 9 on the inner wall of the coating tank 1 is the type A shown in FIG. 9, the type B shown in FIG. 10, or the type C shown in FIG. The same as in Example 2 except that the number of the rectifying grooves 9 on the inner wall of the tank 1 was two and the coating tank 1 was provided with an outflow groove 8 having a width of 5 mm and a depth of 2 mm at the opening end of the coating tank. A laminated electrophotographic photosensitive member was produced. In this reference example, the outflow groove 8 is provided 90 degrees away from the rectifying groove 9 as shown in FIG. FIG. 22 corresponds to FIG.

Image evaluation experiment The electrophotographic photosensitive member produced in the electrophotographic photosensitive member production experiment was printed on a digital copier (manufactured by Sharp Corporation: AR-455), and the initial halftone image was evaluated according to the following evaluation criteria. did. Table 2 summarizes the evaluation results in the image evaluation experiment.

In the evaluation experiment, when it is determined that the initial halftone image is “no image density unevenness, streak unevenness, ring-shaped unevenness application defect, and excellent image characteristics”, Table 2 shows VG (very good). did.
In the evaluation experiment, when it is determined that the initial halftone image is “image density unevenness, streak unevenness, ring-shaped unevenness is slightly present, and image characteristics have no problem in practical use”, G (good) in Table 2 expressed.
In the evaluation experiment, when it is determined that the initial halftone image is “image density unevenness, streak unevenness, ring-shaped unevenness, and image characteristics have problems in actual use”, it is expressed as B (bad) in Table 2. .
When it was determined in the evaluation experiment that the initial halftone image was “there were many image density unevenness, streak unevenness, ring-shaped unevenness, and inferior image characteristics”, it was expressed as VB (very bad) in Table 2. .

1. Evaluation of the initial halftone image printed by the digital copying machine equipped with the photoconductors prepared in Examples 1 and 2 and Comparative Examples 1 and 2 The photoconductors obtained in Examples 1 and 2 were installed in the initial halftone image evaluation. The printed matter produced by the digital copying machine had no defects at all, or slight irregularities that could be ignored were observed, and a good image that did not hinder normal use was obtained. In addition, the printed matter by the photoconductors according to Comparative Examples 1 and 2 showed halftone unevenness, streak unevenness, and ring-shaped unevenness due to uneven application of the photosensitive layer on the image, and only an image with inferior image quality was obtained. .

2. Evaluation of initial halftone image printed by digital copier equipped with photoconductor manufactured in Examples 3 to 10 Printed matter by digital copier equipped with photoconductor obtained in Examples 3 to 10 in initial halftone image evaluation None of them had any defects such as coating unevenness, and an excellent image quality was obtained.

3. Evaluation of initial halftone image printed by digital copier equipped with photoconductor prepared in Examples 11 to 13 Printed matter by digital copier equipped with photoconductor obtained in Examples 11 to 13 in initial halftone image evaluation None of them had any defects such as coating unevenness, and an excellent image quality was obtained.
In addition, in Examples 11 to 13, as a durability test, image characteristics after 10,000 live-action Aging were performed in a high temperature and high humidity environment of 30 degrees 80% RH and a low temperature and low humidity environment of 5 degrees 20% RH. Was evaluated, in Examples 11 to 13, there was no occurrence of image unevenness due to application unevenness as in the initial stage.

4). Evaluation of initial halftone image printed by digital copier equipped with photoconductor manufactured in Reference Examples 1 to 3 Printed matter by digital copier equipped with photoconductor obtained in Reference Examples 1 to 3 in initial halftone image evaluation As a result, streaks and ring unevenness occurred and the image quality was inferior. The cause of this is not clear, but it is considered that the coating liquid supplied from the lower part of the coating tank rises to the upper part of the coating tank when the undercoat layer or the photosensitive layer is formed, and the flow of the coating liquid is disturbed when it overflows. .
In addition, as an endurance test, when the image characteristics after 10,000 live-action Aging were performed in a high temperature and high humidity environment of 30 degrees and 80% RH and a low temperature and low humidity environment of 5 degrees and 20% RH, Comparative Example 3 was evaluated. In .about.5, halfton unevenness became very noticeable after aging, and the level of image unevenness that occurred in the initial stage deteriorated.

    DESCRIPTION OF SYMBOLS 1: Coating tank 2: Bottom part 3: Conductive support body 4: Inner side surface 5: Coating liquid 6: Bottom part supply port 7: Top opening 8: Outflow groove 9: Rectification groove 10: Overflow tank 12: Circulation path 14: Stirring tank 15: Stirring device 16: Lifting device 17: Pump 18: Motor 19: Rotating shaft 20: Coating device 22: Undercoat layer 24: Photosensitive layer 26: Charge generation layer 27: Charge transport layer 29: Overcoat layer 30: Electrophotography Photoconductor 32: Rotating axis 33: Rotation drive direction 34: Charger 34a: Charging roller 34b: Bias power supply 35: Developer 35a: Developing roller 35b: Casing 36: Transfer device 37: Cleaner 37a: Cleaning blade 37b: Recovery casing 38: Exposure means 38a: Laser (Light) 39: transfer paper moving direction 40: transfer paper 41: fixing device 41a: heat roller 41b: press roller 45: the image forming apparatus

Claims (13)

A coating tank that can accommodate a conductive support and can flow a coating solution,
The coating tank includes a bottom supply port for supplying a coating liquid, an upper opening into which the conductive support can be inserted, and allows the coating liquid to flow out of the coating tank due to overflow. A straight rectifying groove provided on the side surface,
The rectifying groove rectifies the coating liquid when the coating liquid flows from the bottom supply port to the upper opening.   The said upper opening is an apparatus of Claim 1 containing the outflow groove provided in the edge part of the side wall of the said coating tank.   The apparatus according to claim 2, wherein two or more outflow grooves are provided at equal intervals.   The apparatus according to claim 2, wherein the outflow groove is a groove connected to the rectifying groove.   The apparatus according to any one of claims 1 to 4, wherein the coating tank has a cylindrical shape, and one end is a bottom portion and the other end is the upper opening.   The apparatus according to claim 5, wherein the rectifying groove is provided substantially in parallel with a cylindrical axial direction of the coating tank. A method for producing an electrophotographic photosensitive member using the apparatus according to any one of claims 1 to 6,
Immersing the conductive support in a coating solution stored in the coating tank;
A step of removing the conductive support from the coating solution,
The step of taking out the conductive support from the coating solution is a method for producing an electrophotographic photosensitive member accompanied by overflow of the coating solution from the upper opening. The upper opening includes an outflow groove provided at an end of a side wall of the coating tank,
The manufacturing method according to claim 7, wherein the step of taking out the conductive support from the coating liquid involves an overflow of the coating liquid from the outflow groove.   The manufacturing method according to claim 7 or 8, wherein the coating liquid stored in the coating tank is a dispersion liquid in which at least one of an inorganic pigment, an organic pigment, and insoluble resin fine particles is dispersed.   The manufacturing method according to claim 7, wherein the coating liquid stored in the coating tank is a coating liquid for an undercoat layer.   The manufacturing method according to claim 7, wherein the coating liquid stored in the coating tank is a charge generating layer coating liquid.   An electrophotographic photosensitive member manufactured by the apparatus according to any one of claims 1 to 6 or by the manufacturing method according to any one of claims 7 to 11.   An image forming apparatus on which the electrophotographic photosensitive member according to claim 12 is mounted.