JP2003066633A - Coating device for organic photoreceptor, method for coating and organic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating device and method for coating an organic photoreceptor by which irregularity in the thickness of the coating film can be suppressed, and to provide an organic photoreceptor manufactured by the method. SOLUTION: In the coating device for an organic photoreceptor by dipping a cylindrical conductive base body in a coating liquid and drawing up to coat, the coating device is equipped with a coating tank which houses the coating liquid for charge transfer layer using a nonhalogen solvent, a solvent vapor reservoir disposed on the coating tank, and a drying hood disposed above the solvent vapor reservoir. The solvent vapor reservoir covers the upper part of the coating tank, and a discharge port is formed between the solvent vapor reservoir and the drying hood above the reservoir.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating device for an organic photoreceptor, a coating method, and an organic photoreceptor manufactured by the coating method. In particular, in the production of an organic photoreceptor, an organic material is formed on the outer peripheral surface of a cylindrical conductive substrate. The present invention relates to a coating device for forming a photosensitive layer, a coating method, and an organic photoconductor manufactured by the coating method.

[0002]

2. Description of the Related Art Heretofore, as a photoconductive material constituting a photosensitive layer of an electrophotographic photosensitive member, inorganic compounds such as selenium, cadmium sulfide and zinc oxide and organic compounds represented by polyvinylcarbazole have been proposed. In the laminated organic photoreceptor in which the photosensitive layer is separated into a charge generating layer and a charge transporting layer, as the charge generating material and the charge transporting material,
Various organic compounds have been proposed and put into practical use as organic photoconductors. Conventionally, as a coating method for such an organic photoreceptor, a dip coating method, a spray coating method, a spin coating method,
Bead coating method, wire bar coating method, blade coating method,
Various coating methods such as a roller coating method, an extrusion coating method, and a curtain coating method are known. Particularly, as a method for forming a uniform photosensitive layer on the outer peripheral surface of a cylindrical conductive substrate, a dip coating method is widely used. Has been.

In recent years, downsizing of devices such as copiers, printers and facsimiles using organic photoconductors has been proposed.
There is a strong demand for weight reduction, and along with this, the diameter of organic photoconductors is being reduced year by year. As a method for producing an organic photoconductor, particularly an organic photoconductor using a small-diameter cylindrical conductive substrate by a dip coating method, from the viewpoint of improving productivity, JP-A-5-88385 and JP-A-6-262113. As described in the publication, a multiple simultaneous dip coating method in which a plurality of cylindrical conductive substrates are simultaneously dipped in a coating solution and pulled up is generally adopted. In particular, if the space between the cylindrical conductive substrates is narrowed, the productivity is further increased, which is advantageous. At that time, the solvent vapor generated from the coating film formed when the cylindrical conductive substrate is pulled up, or the coating tank. Due to the influence of solvent vapor generated from the liquid surface, the touch-drying speed of the coating film formed on the cylindrical conductive substrate is non-uniform between the cylindrical conductive substrates and within one cylindrical conductive substrate. And film thickness unevenness occurs. As a workaround,
As described in JP-A-59-127049, etc., when the cylindrical conductive substrate is not pulled up from the liquid level of the coating tank, air is sent from the outside to the vicinity of the liquid receiving tank, and from the vicinity of the liquid receiving tank. An ON-OFF mechanism in which a solvent vapor discharge port is provided in the vicinity of a liquid receiving tank, as described in JP-A-3-151, etc., in which the solvent vapor concentration is reduced in advance to accelerate the touch drying speed. The unevenness of the film thickness is suppressed by controlling the solvent vapor concentration around the cylindrical conductive substrate at the time of pulling up from the liquid level of the coating tank by connecting to the forced exhaust device provided with.

However, in the above technique, the solvent vapor concentration is low near the air supply port and around the cylindrical conductive substrate in the vicinity of the solvent vapor discharge port connected to the forced evacuation device, but it is high in the distant place. Therefore, it was difficult to make the solvent vapor concentration uniform.

That is, the conventional workaround for the problem that the solvent vapor concentration around the cylindrical conductive substrate becomes non-uniform during dip coating is not sufficient. That is, in the conventional technique as described above, the solvent vapor concentration on the coated surface of the cylindrical conductive substrate varies depending on the location, which causes unevenness in drying of the coated surface, resulting in uneven coating film thickness.

As a measure for avoiding the non-uniformity of the solvent vapor concentration, for example, as shown in FIG. 1 (see FIG. 1) of Japanese Patent Laid-Open No. 8-220786, the liquid in the coating tank 6 is in the middle of the recycle pipe 8. Method for uniformizing the solvent vapor concentration on the liquid surface of the coating tank by using a coating apparatus having a solvent vapor outlet 12 provided at a position lower than the surface and using a solvent having a specific gravity heavier than air and a relatively low saturated vapor pressure Is proposed. However, in this method, by using a solvent with a low saturated vapor pressure, the drying speed tends to be slow, and the coating film easily flows until it reaches dryness to the touch (because it does not become sticky to the touch with the finger). , The coating film at the coating tip becomes thin, the leading thin film becomes long, and unevenness in film thickness easily occurs. In particular,
In the case of coating a charge transport layer having a large coating thickness (thickness containing a large amount of solvent immediately after coating), unevenness in the thickness and increase of the leading thin film are likely to occur before touch-drying is reached.

On the other hand, as a coating solvent for an organic photoreceptor, a halogen solvent has been widely used because of its good solubility of a binder and a charge transporting substance. In recent years, however, a halogen solvent has been feared because of the fear of destroying the global environment. The use of is being regulated more and more year by year. Therefore, dioxolane, dioxane, etc. have been proposed as a solvent instead of the halogen solvent. However, when a large number of simultaneous coatings by a conventional apparatus were performed using these solvents, unevenness in the film thickness and the increase of the leading film thickness were remarkable. It was found. It is considered that this is because these solvents have a low vapor pressure at a normal application temperature and a long drying time until touch drying.

[0008]

Therefore, the present invention has been made for the purpose of solving the above-mentioned problems in the prior art. That is, the object of the present invention is to discharge the solvent vapor generated from the coating film formed when the cylindrical conductive substrate is pulled up and the solvent vapor evaporated from the liquid surface of the coating tank as uniformly as possible around the cylindrical conductive substrate. , Using a non-halogen solvent with a low saturated vapor pressure at room temperature,
An object of the present invention is to provide an organic photoreceptor coating apparatus that can evenly discharge a solvent even when a charge transport layer having a large coating thickness is applied, has a small thickness variation, and has a short leading thin film. Another object of the present invention is to provide a method for coating an organic photoconductor, which is capable of forming a photosensitive layer or the like on a cylindrical conductive substrate using the coating apparatus, and the coating method. An object is to provide an organophotoreceptor manufactured by using the method.

[0009]

The above object of the present invention can be achieved by the following constitution.

1. In a coating device for an organic photoreceptor in which a cylindrical conductive substrate is dipped in a coating liquid and then pulled up and coated,
The coating apparatus has a coating tank containing a coating liquid for a charge transport layer using a non-halogen solvent, a solvent vapor storage chamber provided on the coating tank, and a drying hood provided above the solvent vapor storage chamber. An apparatus for coating an organic photoreceptor, wherein the solvent vapor storage chamber covers an upper portion of a coating tank, and a discharge port is provided between the solvent vapor storage chamber and a drying hood above the solvent vapor storage chamber.

2. The gap width of the discharge port is 0.1 to 10 m
The coating device for an organic photoconductor as described in 1 above, wherein the coating device is m.

3. The discharge port has a dry hood circumference of 50.
3. The coating device for an organic photoconductor according to the item 2, wherein the coating device is formed with an opening ratio of 100%.

4. A recycle pipe is connected to the solvent vapor storage chamber, and the overflowing coating liquid is collected by the recycle pipe and circulated, so as to coat the organic photoconductor according to any one of the above 1 to 3. apparatus.

5. 5. The organophotoreceptor coating apparatus according to any one of 1 to 4 above, wherein the non-halogen solvent is a cyclic ether.

6. 6. The organophotoreceptor coating apparatus according to any one of 1 to 5 above, wherein the cyclic ether is at least one selected from dioxolane, dioxane, and tetrahydrofuran.

7. The coating method for an organic photoreceptor using the coating apparatus according to any one of 1 to 6 above, wherein a cylindrical conductive substrate is applied to a charge transport layer coating liquid while discharging a halogen-free solvent vapor from the outlet. A method for coating an organic photoreceptor, which comprises immersing in a substrate and pulling it up to form a charge transport layer.

8. The coating thickness of the charge transport layer is 30 to 3
7. The method for applying an organic photoreceptor as described in 6 above, which has a thickness of 00 μm.

9. 9. The method for coating an organic photoreceptor as described in 7 or 8 above, wherein a solvent having a saturated vapor pressure at room temperature of 1.3 to 40 kPa is used as a solvent for the coating solution.

10. 10. The method for coating an organic photoconductor according to any one of 7 to 9 above, wherein a plurality of cylindrical conductive substrates are simultaneously immersed in a coating solution and pulled up to form a coating layer.

11. A charge generation layer on a cylindrical conductive substrate,
The charge transport layer of the organic photoreceptor having the charge transport layer is the above
Item 10. An organic photoconductor manufactured by using the method for coating an organic photoconductor according to any one of items 10.

The present invention will be described in detail below. That is, in a coating device for an organic photoreceptor in which a cylindrical conductive substrate is dipped in a coating liquid and pulled up for coating, the coating device is a coating tank containing a charge transport layer coating liquid using a non-halogen solvent,
It has a solvent vapor reservoir chamber provided on the coating tank and a drying hood provided above the solvent vapor reservoir chamber, the solvent vapor reservoir chamber covers the upper portion of the coating tank, and the solvent vapor reservoir chamber and the drying above it. A discharge port is provided between the hood and the hood.

Further, the coating method of the present invention is the same as the method for manufacturing an organic photoconductor using the above-mentioned apparatus for coating an organic photoconductor, while the non-halogen solvent vapor is discharged from the discharge port while the charge is transferred on the cylindrical conductive substrate. It is characterized in that the charge transport layer is formed by immersing in a layer coating liquid and pulling it up.

Further, the organic photoreceptor of the present invention has a charge generation layer and a charge transport layer on a cylindrical conductive substrate, and the charge transport layer is produced by the above-mentioned coating method for the organic photoreceptor. And

The coating method in the present invention is a coating apparatus in which a drying hood installed on a coating tank is separated into a solvent vapor reservoir chamber and a drying hood, and an exhaust port is provided between the solvent vapor reservoir chamber and the drying hood. By discharging the solvent vapor from the exhaust port, the solvent vapor concentration in the entire solvent vapor reservoir is made uniform, and the solvent vapor concentration immediately after coating is eliminated between the substrates or by the circumferential direction of the substrate. The thickness unevenness can be reduced. Furthermore, by providing an outlet directly above the solvent vapor storage chamber, solvent vapor is not directly sucked into the drying hood that follows it, and the concentration of solvent vapor in the drying hood can be reduced, and the finger of the coating film can be reduced. Touch drying can be accelerated, and even in the case of a charge transport layer coating film using a non-halogen solvent such as a cyclic ether, which has a relatively low drying rate, it is possible to prevent unevenness in film thickness and increase in the leading thin film.

That is, by providing the discharge port directly above the solvent vapor reservoir chamber, the solvent vapor can be easily discharged, and a large amount of solvent vapor immediately after coating can be discharged. In addition, since the solvent vapor can be uniformly discharged from the periphery of the cylindrical conductive substrate, the solvent concentration in the solvent vapor reservoir chamber can be kept uniform even in one coating apparatus or a large number of coating apparatuses. The solvent can be discharged out of the system. As a result, even if a thick charge transport layer having a coating film thickness (coating liquid film thickness containing a solvent immediately after coating) of 30 to 300 μm is applied, the unevenness of the film thickness can be reduced and the leading thin film can be shortened.

Even if a non-halogen solvent such as a cyclic ether having a low saturated vapor pressure of 1.3 to 40 kPa at room temperature (20 ° C.) is selected as the coating solvent for the charge transport layer, the unevenness of the film thickness and the leading thin film can be obtained. The improvement effect of shortening can be maintained.

Here, the leading thin film means a phenomenon that the coating film immediately after coating flows down under the influence of gravity and the film thickness becomes thin at the tip of the coating, and the coating film thickness is large and the drying speed is slow. It is likely to occur in the charge transport layer. FIG. 4 shows the film thickness profile of the photoreceptor coated with the charge transport layer.
a indicates the leading thin film portion.

In the present invention, the organic photoconductor is an electrophotographic photoconductor having an organic compound having either one of the charge generating function and the charge transporting function, which are essential for the construction of the electrophotographic photoconductor. This means that it includes all known organic electrophotographic photoreceptors such as a photoreceptor composed of a known organic charge generating material or an organic charge transporting material and a photoreceptor composed of a polymer complex having a charge generating function and a charge transporting function.

The organic photoreceptor of the present invention has a charge generation layer and a charge transport layer on a cylindrical conductive substrate, but a layer structure in which an intermediate layer is provided between the cylindrical conductive substrate and the charge generation layer is more preferable. Hereinafter, the layer structure of the organic photoreceptor preferably used in the present invention will be described.

Cylindrical Conductive Substrate The cylindrical conductive substrate means a cylindrical substrate necessary for endlessly forming an image by rotating, and has a straightness of 0.1 mm or less and a shake of 0.1 mm or less. Conductive substrates in the range are preferred. When the circularity and the shake range are exceeded, good image formation becomes difficult.

As the conductive material, a metal drum of aluminum, nickel or the like, a plastic drum having aluminum, tin oxide, indium oxide or the like deposited thereon, or a paper / plastic drum coated with a conductive substance can be used. As a conductive substrate, the specific resistance is 1 at room temperature.
It is preferably 0 ³ Ωcm or less.

The conductive substrate used in the present invention may have a surface on which a sealed alumite film is formed. Alumite treatment is usually, for example, chromic acid,
It is carried out in an acidic bath of sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid, etc., but anodizing in sulfuric acid gives the most favorable results. In the case of anodizing treatment in sulfuric acid,
It is preferable that the sulfuric acid concentration is 100 to 200 g / L, the aluminum ion concentration is 1 to 10 g / L, the liquid temperature is about 20 ° C., and the applied voltage is about 20 V, but the present invention is not limited thereto. The average thickness of the anodized film is usually 20μ.
m or less, and particularly preferably 10 μm or less.

Intermediate layer In the present invention, a resin layer formed by a reaction of an organic resin or an organometallic compound between the conductive substrate and the photosensitive layer,
Alternatively, it is preferable to provide an intermediate layer in which semiconductor particles such as titanium oxide are dispersed in an organic resin. By providing such an intermediate layer, it is possible to prevent entry of free charges from the conductive substrate. The thickness of the intermediate layer is preferably 0.1 to 20 μm.

Photosensitive Layer The photosensitive layer structure of the photoconductor of the present invention may be a photosensitive layer structure of a single layer structure in which one layer has a charge generating function and a charge transporting function on the above-mentioned intermediate layer, but more preferably, it is photosensitive. It is preferable that the function of the layer is separated into a charge generation layer (CGL) and a charge transport layer (CTL). By adopting a constitution in which the functions are separated, the increase in residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negative charging photoreceptor, the charge generation layer (C
GL) and a charge transport layer (CTL) thereon. In the case of the photoconductor for positive charging, the order of the layers is the reverse of that of the photoconductor for negative charging. The most preferable photosensitive layer structure of the present invention is a negatively charged photosensitive member structure having the above-mentioned function separation structure.

The constitution of the photosensitive layer of the function-separated negatively charged photoreceptor will be described below. Charge Generation Layer The charge generation layer contains a charge generation material (CGM). If necessary, a binder resin and other additives may be contained as other substances.

As the charge generating substance (CGM), a known charge generating substance (CGM) can be used. For example, a phthalocyanine pigment, an azo pigment, a perylene pigment, an azurenium pigment or the like can be used. Among these, CGM that can minimize the increase in residual potential with repeated use
Has a steric structure and a potential structure capable of forming a stable aggregation structure among a plurality of molecules, and specific examples thereof include a phthalocyanine pigment and a perylene pigment CGM having a specific crystal structure. For example, the Bragg angle 2θ with respect to Cu-Kα rays
CGMs such as titanyl phthalocyanine having a maximum peak at 27.2 ° and benzimidazole perylene having a maximum peak at 22.4 at 27.2 have almost no deterioration due to repeated use, and the residual potential increase can be reduced.

When a binder is used as a CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferable resin is formal resin, butyral resin, silicone resin, silicone modified butyral resin, phenoxy resin. Resin etc. are mentioned. The ratio of the binder resin to the charge generating substance is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential due to repeated use can be minimized. The thickness of the charge generation layer is preferably 0.01 μm to 2 μm.

Charge Transport Layer The charge transport layer of the present invention means a layer containing at least a charge transport substance. As long as the charge-transporting substance has a function of transporting holes or electrons generated from the charge-generating substance, any known or new organic compound can be used.

The charge transport layer contains a charge transport material (CTM) and a binder resin for dispersing CTM to form a film.
Other substances may optionally contain additives such as antioxidants.

As the charge transport material (CTM), a known charge transport material (CTM) can be used. For example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound or the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer. Among these, CTM that can minimize the increase in residual potential due to repeated use has high mobility and has a characteristic that the difference in ionization potential with CGM to be combined is 0.5 (eV) or less, and preferably 0. It is 0.25 (eV) or less.

The ionization potentials of CGM and CTM are measured by a surface analyzer AC-1 (manufactured by Riken Keiki Co., Ltd.).

Examples of the resin used for the charge transport layer (CTL) include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd. Resins, polycarbonate resins, silicone resins, melamine resins, and copolymer resins containing two or more of the repeating units of these resins. In addition to these insulating resins, poly-
Examples include polymer organic semiconductors such as N-vinylcarbazole.

The most preferable binder for these CTLs is a polycarbonate resin. Polycarbonate resin is most preferable in improving dispersibility of CTM and electrophotographic characteristics. The ratio of the binder resin to the charge transport material is preferably 10 to 200 parts by mass with respect to 100 parts by mass of the binder resin. The thickness of the charge transport layer is preferably 10-40 μm.

Protective Layer The organic photoreceptor of the present invention may be provided with a protective layer forming a surface layer having a low surface energy. For example, a protective layer of a siloxane-based resin layer, a protective layer containing a fluorine-based resin, or the like may be provided on the photosensitive layer.

Although the most preferable layer constitution of the photoconductor of the present invention has been exemplified above, a photoconductor layer constitution other than the above may be used in the present invention.

The coating liquid for producing each layer constituting the organic photoreceptor of the present invention requires a solvent capable of dissolving the components of each layer. Although the present invention is characterized in that a non-halogen solvent is used as the solvent of the charge transport layer, it is preferable to use a non-halogen solvent in each of the other layers. Examples of the non-halogen solvent include various solvents such as alcohols and ketones, and as the coating liquid solvent for the charge transport layer of the present invention, cyclic ethers such as dioxolane, dioxane and tetrahydrofuran are particularly preferable. These solvents are excellent in solubility of known charge generating substances and binder resins of the charge generating layer, and are also very excellent in terms of environmental load to the global environment. Further, the above cyclic ether may be mixed with alcohols, ketones, aromatic solvents and the like.

Further, the coating apparatus or the coating method of the present invention can be suitably applied to the formation of the undercoat layer and the charge generation layer of the organic photoreceptor. However, particularly when the coating method of the present invention is applied to the charge transport layer in which the coating film thickness exceeds 50 μm and the unevenness of the film thickness and the occurrence of the leading thin film are large, good results are obtained. Moreover, the present invention is particularly effective for simultaneous coating of a large number of coating films in which coating films are simultaneously formed on the outer peripheral surfaces of a plurality of cylindrical conductive substrates. At that time, in order to improve the uniform solvent vapor discharge effect by the plurality of cylindrical conductive substrates arranged in the coating tank,
A coating tank is preferable in which the arrangement configurations of the respective cylindrical conductive substrates are the same. That is, a cylindrical coating tank for simultaneous coating of four as shown in FIG. 5 is preferable, and in a coating apparatus of five or more, it is preferable to arrange so that the distance between adjacent cylindrical conductive substrates is equal.

FIG. 2 shows a schematic structure of an example of the single-dip dipping coating apparatus of the present invention. The cylindrical conductive substrate 9 is shown in FIG.
Is subjected to dip coating in the coating tank 6 and then is being pulled up from the coating tank. In the present invention, when the cylindrical conductive substrate is pulled up from the coating tank, it enters the solvent vapor reservoir chamber 11 where the coating film releases a large amount of solvent vapor and is sent to the next drying hood 14 to be dry to the touch. (It is not sticky to the touch with your fingers). In the present invention, the solvent vapor reservoir 1
By providing the discharge port 12 between the 1 and the drying hood 14, even when a solvent having a high saturated vapor pressure is used for the coating liquid,
Further, even when a coating film of 50 μm or more that releases a large amount of solvent vapor is formed, a large amount of solvent vapor can be released while maintaining a uniform solvent vapor concentration in the solvent vapor reservoir chamber 11 as a whole. It prevents the dryness of the film from being touched to the touch and the increase of the leading thin film.

Here, the solvent vapor reservoir covers the coating layer,
This is a room for temporarily stagnating the solvent vapor generated from the coating liquid or coating film and maintaining an atmosphere with a uniform solvent vapor concentration. The height of the solvent vapor storage chamber is preferably 1 cm to 100 cm. If it is less than 1 cm, the effect of providing the solvent vapor reservoir is small, and the effect of preventing unevenness of film thickness is small. While 10
Even if it is larger than 0 cm, the effect commensurate with the increase in size of the apparatus cannot be obtained.

The outlet of the present invention is formed between the solvent vapor reservoir and the drying hood so as to surround the cylindrical conductive substrate when the coated substrate is pulled up. That is, the discharge port 12 has a space of 0.1 between the solvent vapor storage chamber and the drying hood.
It is preferable to install with a gap width of 10 mm. 0.1 m
If it is less than m, the solvent vapor discharge amount is not sufficient, and if it is 10 mm or more, the solvent vapor discharge amount is sufficient, but the solvent vapor reservoir chamber is easily affected by the flow of external air, and the solvent vapor concentration in the solvent vapor reservoir chamber is large. Is easily disturbed.

The upper lid portion of the solvent vapor storage chamber is provided with an opening (hole) necessary for passing the cylindrical conductive substrate. The opening is preferably circular like the cylindrical conductive substrate.

The length of the dry hood (having a structure surrounding the cylindrical conductive substrate) installed in the upper part of the solvent vapor reservoir is preferably 5 cm to 300 cm. When it is less than 5 cm, the effect of the dry hood is small, and the effect of preventing the occurrence of uneven film thickness is small. On the other hand, if it is larger than 300 cm, the effect commensurate with the increase in size of the device cannot be obtained.

Further, it is preferable that a recycle pipe is installed in the solvent vapor reservoir to keep the liquid level in the coating tank constant. That is, it is preferable to have a configuration as shown in FIG. That is, the coating liquid 1 is supplied from the coating liquid tank 2 to the supply pipe 3
Is pumped by the pump 4 through the filter, and is supplied into the coating tank 6 through the filter 5. The coating liquid supplied to the coating tank 6 overflows, is collected by the coating liquid receiving tank 7 continuously provided at the lower end of the solvent vapor reservoir 11 and flows out to the recycle pipe 8, and is collected in the coating liquid tank 2. To be done. When performing dip coating using this dip coating device, when the cylindrical conductive substrate 9 is dipped in the coating tank 6 and then withdrawn, it constantly overflows for the purpose of keeping the liquid level 10 of the coating tank constant. Thus, the coating liquid is circulated by the coating liquid circulating means. Further, the discharge port 12 for discharging the solvent vapor is provided on the solvent vapor storage chamber.
It is provided at a position higher than the liquid level 10 of the coating tank. Also,
A drying hood 14 is provided above the solvent vapor storage chamber 11 to prevent the influence of the flow of external air. Here, when the discharge port 12 is not provided, or when the discharge port 12 is installed in the middle of the recycling pipe 8 which is lower than the liquid level 10 of the coating tank as in JP-A-8-220786, a large amount of solvent vapor of 50 μm is discharged. When the above coating film is formed, the solvent vapor concentration in the solvent vapor reservoir chamber 11 cannot be sufficiently discharged, and the solvent vapor stays around the cylindrical conductive substrate and the cylindrical conductive substrate 9
The unevenness of the coating film formed on the surface is caused by touch-drying, and the leading thin film is increased. However, in the present invention, since the discharge port 12 for discharging the solvent vapor is provided at a position higher than the coating tank liquid level 10 on the solvent vapor storage chamber, for example, 50 μm.
Even if a coating film having a thickness of m or more is formed, it is possible to uniformly discharge the solvent vapor around the cylindrical conductive substrate, and the effect thereof can prevent the occurrence of film thickness unevenness and the increase of the leading thin film.

FIG. 3 shows a schematic structure of an example of the multiple simultaneous dip coating apparatus of the present invention, showing a state where the cylindrical conductive substrate is being pulled up from the coating tank. The coating liquid 1 is pumped from the coating liquid tank 2 through the supply pipe 3 to the pump 4
It is pressure-fed by and is supplied into the coating tank 6 through the filter 5. A mesh 15 is inserted in the lower part of the coating tank 6 in order to obtain uniform coating liquid flow velocity in the tank. The coating liquid supplied into the coating tank 6 overflows and is collected in a continuous coating liquid receiving tank 7 at the lower end of a solvent vapor reservoir 11 installed at the upper portion of the coating tank 6 and flows out to a recycling pipe 8 for coating and coating. It is collected in the liquid tank 2. When performing dip coating using this dip coating device, when the cylindrical conductive substrate 9 is dipped in the coating tank 6 and then withdrawn, it constantly overflows for the purpose of keeping the liquid level 10 of the coating tank constant. Thus, the coating solution is circulated by the circulation means. Further, a solvent vapor storage chamber is installed above the coating tank, and a drying hood is provided on the solvent vapor storage chamber. An outlet 12 for discharging the solvent vapor is provided between the solvent vapor storage chamber and the drying hood. The discharge port 12 is provided at a position higher than the liquid level 10 of the coating tank.

In the case of applying a large number of dry hoods, it is possible to install the dry hood on the solvent vapor storage chamber with the same outer wall structure as the solvent vapor storage chamber, but in the periphery of each cylindrical conductive substrate. In order to maintain a constant solvent vapor concentration of, the dry hood is preferably installed independently on each cylindrical conductive substrate. FIG. 3 illustrates an example in which a drying hood is independently installed on a large number of cylindrical conductive substrates.

[0056]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 An intermediate layer was formed on a cylindrical conductive substrate as follows.

Polyamide resin CM8000 (manufactured by Toray)
1 part by mass and 10 parts by mass of methanol were added to the same container and dissolved and dispersed to prepare an intermediate layer coating liquid 1. The coating solution for the intermediate layer was coated on a cylindrical aluminum substrate (1.0 mmt × 30 mmφ × 340 mm) by using the dip coating apparatus shown in FIG. The coating liquid temperature at that time was 24 ° C. The speed of pulling up the aluminum substrate from the coating solution is 480 mm / mi
It was set to n. As the position of the discharge port 12, a gap width of 1 mm is installed between the solvent vapor storage chamber and the drying hood shown in FIG. The outlet is 50 cm at a height of 10 cm from the surface of the coating tank.
It is formed by a circle of mm. The coating liquid circulation flow rate is 1
L / min, the diameter of the recycle pipe 8 is 100 mmφ
And The coated substrate was air-dried through a 15 cm dry hood, then placed in a drier and dried by heating at 70 ° C. for 10 minutes to form an intermediate layer having a film thickness of 0.1 μm.

Next, 60 parts by mass of Y-type titanyl phthalocyanine and a silicone-modified butyral resin (manufactured by Shin-Etsu Chemical Co., Ltd.) 7
00 parts by mass and 2000 ml of 2-butanone were mixed and dispersed for 10 hours using a sand mill to prepare a charge generation layer coating liquid. This coating solution was applied onto the aluminum substrate on which the intermediate layer obtained in Example 1 was formed by using the dip coating apparatus shown in FIG. The rate of pulling up the aluminum substrate from the coating solution was 480 mm / min. The coating liquid temperature at that time was 24 ° C. As the position of the discharge port 12, a gap width of 1 mm is installed between the solvent vapor storage chamber and the drying hood shown in FIG. The discharge port is 1 from the liquid level of the coating tank.
It is formed with a circle of 50 mm at a height of 0 cm. Also,
The coating liquid was circulated at a flow rate of 1 L / min and the recycle tube 8 had an inner diameter of 100 mmφ. The applied aluminum substrate was air-dried through a 15 cm dry hood, and then a charge-generating layer (dry film thickness: 0.5 μm) that was dry to the touch (dry state that was not sticky to the touch with a finger) was formed.

Next, a charge transport layer was formed on the charge generation layer formed above. Charge transport material [N- (4-
Methylphenyl) -N- {4- (β-phenylstyryl) phenyl} -p-toluidine] 225 parts by mass, polycarbonate (viscosity average molecular weight 20,000) 300 parts by mass, antioxidant (Exemplary compound 1-3) 6 By mass, 2000 parts by mass of dioxolane were mixed and dissolved to prepare a charge transport layer coating liquid. This coating solution is applied onto the charge generation layer by a dip coating method to obtain a coating film thickness of 95 μm and a dry film thickness of 20
A μm charge transport layer was formed. The speed of pulling up the aluminum substrate from the coating solution was 240 mm / min. The coating liquid temperature at that time was 24 ° C. As the position of the discharge port 12, a gap width of 1 mm is installed between the solvent vapor storage chamber and the drying hood shown in FIG. The discharge port is formed as a circle of 50 mm at a height of 10 cm from the liquid level of the coating tank. The circulating flow rate of the coating liquid was 1 L / min, and the diameter of the recycle pipe was 100 mmφ. The coated aluminum substrate was air-dried via a 15 cm dry hood, then placed in a drier and dried by heating at 90 ° C. for 60 minutes to form a charge transport layer, and an organic photosensitive drum was produced. Under these conditions, coating was repeated 4 times. Table 1 shows the respective film thickness unevenness values. The thickness unevenness value is 20 from the upper end of the coating film.
mm, 50 mm, 160 mm, and 300 mm in the circumferential direction (intervals of 90 °), and the difference between the maximum value and the minimum value of the film thickness values at 16 points in total. Here, the saturated vapor pressure of dioxolane at 20 ° C. was 9.3 kPa, and the specific gravity with respect to air was about 1.067.

Comparative Example 1 For comparison, the charge generation was performed under the same conditions as in Example 1 except that the discharge port was attached in the middle of the recycling pipe 8 located below the coating liquid surface as shown in FIG. A charge transport layer was applied on top of the layer. The results are shown in Table 1.

[0062]

[Table 1]

Example 2 FIG. 3 and FIG. 5 were prepared using the coating solution for the intermediate layer used in Example 1.
Coating was performed by using the four simultaneous coating device shown in FIG.
Is a diagram of a method of arranging four substrates simultaneously coated). The speed of pulling up the cylindrical aluminum substrate from the coating liquid is 400 mm /
The coating temperature at this time was 24 ° C. As the position of the discharge port 12, a gap width of 1 mm is installed between the solvent vapor reservoir chamber and the drying hood shown in FIG. The discharge port is formed as a circle of 50 mm at a height of 10 cm from the liquid level of the coating tank. The circulating flow rate of the coating solution was 5 L / min, and the diameter of the recycle pipe was 150 mmφ. The coated aluminum substrate was air-dried through a 15 cm dry hood, then placed in a drier and dried by heating at 70 ° C. for 10 minutes to form an intermediate layer having a film thickness of 0.1 μm.

Next, using the same charge generation layer coating solution as in Example 1, and using the four simultaneous coating apparatus shown in FIGS. 3 and 5,
It was applied on an aluminum substrate on which the above intermediate layer was formed. The speed of pulling up the aluminum substrate from the coating solution is 4
It was set to 80 mm / min. The coating temperature at this time was 24 ° C. As the position of the discharge port 12, a gap width of 1 mm is installed between the solvent vapor reservoir chamber and the drying hood shown in FIG. The outlet is 50 m at a height of 10 cm from the liquid level of the coating tank.
It is formed by a circle of m. The coating liquid circulation flow rate is 5
L / min and the diameter of the recycle pipe were 150 mm in diameter. The coated aluminum substrate was air-dried through a 15 cm dry hood, and then dried by touch with a finger (dry state without being sticky to the touch with a finger) to generate a charge generation layer (dry film thickness: 0.5 μm).
m) was formed.

The same charge transport layer coating liquid as in Example 1 was applied onto the above charge generating layer by dip coating to form a charge having a coating film thickness of 95 μm and a dry film thickness of 20 μm. A transport layer was formed. The rate of pulling up the aluminum substrate from the coating solution was 240 mm / min, and the number of simultaneous coatings was 4. The coating temperature at this time was 24 ° C. As the position of the discharge port 12, a gap width of 1 mm is installed between the solvent vapor reservoir chamber and the drying hood shown in FIG. The discharge port is formed as a circle of 50 mm at a height of 10 cm from the liquid level of the coating tank. The coating liquid circulation flow rate is 5 L / min,
The diameter of the recycle pipe was 150 mmφ. The coated aluminum substrate was air-dried through a 15 cm dry hood, then placed in a drier and dried by heating at 90 ° C. for 60 minutes to form a charge transport layer, and an organic photosensitive drum was produced. Table 2 shows the film thickness unevenness values of the four films at that time. Here, the thickness unevenness value is 20 m from the upper end of the coating film.
It is the difference between the maximum value and the minimum value of the film thickness value at four points (90 ° intervals) in the circumferential direction at each of m, 50 mm, 160 mm, and 300 mm, for a total of 16 points. The results are shown in Table 2.

Comparative Example 2 For comparison, a charge transport layer was formed on the charge generation layer under the same conditions as in Example 2 except that the discharge port was attached in the middle of the recycle pipe 8 located below the coating liquid surface. Application was performed. The results are shown in Table 2.

Example 3 Except that the distance between the outlets 12 was set to 8 mm and the solvent for the charge transport layer coating solution was changed from dioxolane to dioxane.
Table 2 shows the results of coating the charge transport layer on the charge generation layer under the same conditions as in Example 2. The saturated vapor pressure of dioxane at 20 ° C. is about 4.0 kPa.

Example 4 The charge transport layer was formed on the charge generation layer under the same conditions as in Example 2 except that the distance between the discharge ports 12 was 0.2 mm and the solvent for the charge transport layer coating solution was changed from dioxolane to tetrahydrofuran. The layers were applied. The results are shown in Table 2.
The saturated vapor pressure of tetrahydrofuran at 20 ° C is about 18
It is kPa.

Further, the leading thin film of each of the photoconductors of Examples 2 to 4 and Comparative Example 2 was evaluated. The results are shown in Table 3. * Evaluation of the leading thin film An arbitrary straight line is selected along the drum axis of the cylindrical photoreceptor. The film thickness of the photosensitive layer is measured at regular intervals of 10 mm from the leading portion of the coating on the straight line, and a photosensitive layer film thickness profile as shown in FIG. 4 is created. The length L of the leading thin film is defined as the length a from the drum tip of the photoconductor to the intersection of the tangent of the leading portion thickness rise and the extension of the saturated thickness. The leading thin film length was measured for each photoreceptor, and the results are shown in Table 3.
The film thickness measuring device is a photodetection type film thickness measuring device MCPD-100.
0 (instantaneous multi-photometric detector: Otsuka Electronics Co., Ltd.) was used.

[0070]

[Table 2]

[0071]

[Table 3]

As can be seen from Table 1, Table 2 and Table 3, the organic solvent of the present invention is provided with a solvent vapor distillation chamber above the coating tank and a solvent vapor discharge port provided between the solvent vapor distillation chamber and the drying hood. The photoconductor coating device has unevenness in film thickness after coating the charge transport layer using a non-halogen solvent, as compared with the coating device provided with a solvent vapor outlet in the middle of the conventional recycling pipe shown in the comparative example. A remarkable improvement effect is seen in any of the lengths of the leading thin films.

[0073]

As is apparent from the above-mentioned embodiments, the use of the organic photoreceptor coating apparatus and coating method of the present invention
The photosensitive layer formed on each cylindrical conductive substrate can have a small thickness unevenness, and the length of the leading thin film can be made small. Therefore, it is possible to provide a cylindrical organic photosensitive member with good performance. Is.

[Brief description of drawings]

FIG. 1 is a view of a coating apparatus in which a solvent vapor discharge port is provided at a position lower than a liquid level of a coating tank in the middle of a recycling pipe.

FIG. 2 is a diagram showing a schematic configuration of an example of a single-dip dipping coating device of the present invention.

FIG. 3 is a diagram showing a schematic configuration of an example of the multiple simultaneous dip coating apparatus of the present invention.

FIG. 4 is a view showing a film thickness profile of a photoreceptor coated with a charge transport layer.

FIG. 5 is a diagram showing a method of arranging four substrates simultaneously coated.

[Explanation of symbols]

1 coating liquid 2 Coating liquid tank 3 supply piping 4 pumps 5 filters 6 coating tanks 7 Coating liquid receiving tank 8 recycling pipes 9 Cylindrical conductive substrate 10 Liquid level of coating tank (overflow surface) 11 Solvent vapor reservoir 12 outlet 14 Dry hood 15 mesh

Claims (11)

[Claims] 1. A cylindrical conductive substrate is dipped in a coating solution,
In an organic photoreceptor coating apparatus for pulling up and coating, the coating apparatus includes a coating tank for containing a charge transport layer coating solution using a non-halogen solvent, a solvent vapor reservoir provided on the coating tank, and the solvent vapor. It has a drying hood provided above the reservoir chamber, the solvent vapor reservoir chamber covers the upper part of the coating tank, and an outlet is provided between the solvent vapor reservoir chamber and the drying hood above it. Organic photoconductor coating device. 2. The gap width of the discharge port is 0.1 to 10 mm.
The coating device for an organic photoreceptor according to claim 1, wherein 3. The dry outlet has a perimeter of 50 to 50.
The coating device for an organic photoconductor according to claim 2, wherein the coating device is formed with an opening ratio of 100%. 4. The recycle pipe is connected to the solvent vapor storage chamber, and the overflowing coating liquid is collected by the recycle pipe and circulated. Organic photoconductor coating device. 5. The apparatus for coating an organophotoreceptor according to claim 1, wherein the non-halogen solvent is a cyclic ether. 6. The apparatus for coating an organic photoconductor according to claim 1, wherein the cyclic ether is at least one selected from dioxolane, dioxane, and tetrahydrofuran. 7. A method for coating an organic photoreceptor using the coating apparatus according to claim 1, wherein the cylindrical conductive substrate is formed while discharging the non-halogen solvent vapor from the discharge port. A method for coating an organic photoreceptor, which comprises immersing in a coating liquid for a charge transport layer and pulling it up to form a charge transport layer. 8. The coating thickness of the charge transport layer is 30 to 30.
The coating method for an organic photoconductor according to claim 6, wherein the coating thickness is 0 μm. 9. The method for coating an organic photoreceptor according to claim 7, wherein a solvent having a saturated vapor pressure at room temperature of 1.3 to 40 kPa is used as a solvent for the coating solution. 10. The organophotoreceptor according to claim 7, wherein a plurality of cylindrical conductive substrates are simultaneously immersed in a coating solution and pulled up to form a coating layer. Application method. 11. A charge transport layer of an organic photoreceptor having a charge generation layer and a charge transport layer on a cylindrical conductive substrate.
Item 10. An organic photoconductor manufactured by using the method for coating an organic photoconductor according to any one of items 10.