JPH0729076B2 - Coating device - Google Patents

Description

Detailed Description of the Invention a. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating device, for example, a dip coating device for coating and forming a photosensitive layer of an electrophotographic photoreceptor.

B. 2. Description of the Related Art Conventionally, as an electrophotographic photosensitive member, an inorganic photosensitive member having a photosensitive layer containing an inorganic photoconductive substance such as selenium, zinc oxide, or cadmium sulfide as a main component has been widely used.

On the other hand, the use of various organic photoconductive materials as materials for the photosensitive layer of an electrophotographic photoreceptor has been actively developed and studied in recent years. For example, Japanese Patent Publication No. 50-10496 discloses poly-N.
An organophotoreceptor having a photosensitive layer containing -vinylcarbazole and 2,4,7-trinitro-9-fluorenone is described. However, this photoreceptor is not always satisfactory in sensitivity and durability. In order to ameliorate such a defect, an attempt has been made to develop an organic photoreceptor having high sensitivity and high durability by separately sharing a carrier generating function and a carrier transporting function with different substances in a photosensitive layer. ing. In the so-called function-separated type electrophotographic photoreceptor, the substances exhibiting the respective functions can be selected from a wide range of substances, so that an electrophotographic photoreceptor having arbitrary characteristics can be produced relatively easily. It is possible.

When coating and forming the photosensitive layer of such an electrophotographic photosensitive member, since it maintains good sensitivity characteristics and prevents image defects such as density unevenness and exerts good performance as a photosensitive member, it is highly accurate and uniform. The layers need to be applied.

Conventionally, various coating methods such as dip coating, spray coating, spinner coating, wire bar coating, blade coating and roller coating are known as coating methods for the photosensitive layer of an electrophotographic photoreceptor, but mainly dip coating and spraying. Coating is used. Of these, dip coating is often used to form a uniform coating film on a cylindrical object (conductive substrate or the like).

FIG. 8 shows a coating device used for dip coating.

A predetermined coating liquid 1 is contained in the coating tank 2. At the time of dip coating, the cylindrical conductive substrate shown by the solid line (hereinafter,
Sometimes referred to as the base drum. ) 4 is immersed in the coating liquid 1 with the opening 4b facing downward, and then the handle 5a of the lid 5 is gripped and the substrate drum 4 is pulled up at a predetermined speed. Before the substrate drum 4 is dipped, the liquid surface of the coating liquid 1 exists at the position 1b indicated by the alternate long and short dash line, but when the substrate drum 4 is dipped, because of the air filling the hollow portion 4c in the substrate drum 4. ,
The coating liquid 1 is removed from the hollow portion 4c, and the liquid surface drops to the position 1c shown by the solid line. Along with this, the outer peripheral surface of the base drum 4
In the region sandwiched by 4e and the inner peripheral surface 2b of the side wall of the coating tank 2, the liquid surface rises to the position of 1a shown by the solid line, and the coating liquid is applied to the outer peripheral surface 4e of the base drum to the height of the predetermined position 4a. A uniform coating film will be formed. At this time, the liquid level rises by an amount corresponding to the volume of the submerged portion of the substrate drum 4 and the volume of air in that portion, that is, the height l ₃ .

Therefore, such a coating device has the following problems.

That is, since the liquid surface of the coating liquid moves up and down between the position 1b indicated by the alternate long and short dash line and the position 1a indicated by the solid line as the substrate drum 4 is dipped and pulled up, the coating liquid is applied to the inner peripheral surface 2b of the side wall of the coating tank. The liquid 1 adheres, and the applied coating liquid dries to produce a dried solid substance 9. Then, it is considered that the dried solid matter 9 is mixed into the coating liquid 1 to cause a change and deterioration of the components of the coating liquid 1, or cause a so-called foreign matter defect (coating defect).

As a method of preventing such a defect, a so-called overflow method is known, and FIG. 9 shows a schematic sectional view of a dip coating apparatus according to this method.

A predetermined coating liquid 1 is contained in the coating tank 2, and a tray 6 is provided around the side wall 2d of the coating tank 2. Coating liquid 1
Is supplied from the tank 12 by the pump 10, is supplied from the supply port 11 through the supply port 11 into the coating tank 2 as shown by the arrow, and further passes over the upper edge portion 2e of the side wall 2d so as to cover the coating tank 2. It overflows in the circumferential direction, is collected by the tray 6 and is discharged from the discharge port 8 to the tank 12. Cylindrical conductive substrate 4
Is dipped in the coating liquid 1 as indicated by the alternate long and short dash line, and then the conductive substrate 4 is pulled up at a predetermined speed as indicated by the arrow D to perform dip coating. During the dip coating, the coating liquid 1 continues to overflow beyond the upper edge portion 2e of the side wall 2d as described above, so that the height of the liquid surface of the coating liquid 1 is kept constant at the position 1a.

According to such an overflow type coating method, since the liquid surface position is kept constant in the coating apparatus, there is no dry solid matter generation on the inner wall of the coating tank, and even if it is generated, it can be filtered by the filter 14, so that foreign matter adheres. Effective in preventing coating defects.

However, the overflow type coating apparatus has a drawback that a large amount of coating solution is required for the coating tank and the circulation system (for example, several times as much coating solution is required as compared with the coating apparatus of FIG. 8). .). Therefore, the cost of raw materials is high,
Further, when the application liquid reaches the use limit, it is necessary to discard and replace a large amount of the application liquid, which is disadvantageous in terms of cost and the like.

C. Object of the Invention An object of the present invention is to provide coating defects (foreign matter defects) due to foreign matter adhesion.
It is an object of the present invention to provide a coating device that can effectively prevent the above-mentioned problem and that can reduce the amount of the coating liquid required for coating.

D. Configuration of the Invention The present invention is to apply the coating liquid by immersing the coating liquid having both openings in a coating liquid stored in a coating bath and pulling up the coating liquid to form the upper edge of the side wall of the coating bath. A coating device in which a coating liquid overflowing beyond a portion is circulated back into the coating tank, the lid being fitted to one end of an opening of the coating target and used for holding the coating target, and the coating target. A convex body that has an outer diameter smaller than the inner diameter of the coating body and is provided upright in the coating tank, and that the lid and / or the convex body has an opening for degassing. The present invention relates to a coating device having a feature.

E. Examples Hereinafter, examples of the present invention will be described.

The coating apparatus of FIG. 1 is shown, (a) is a sectional view showing a coating tank, and (b) is a sectional view showing a state in which a substrate drum is immersed.

The coating apparatus of FIG. 1 is the same as the coating apparatus of FIG. 9 except that the convex portion 3 is provided. The same functional members are designated by the same reference numerals, and the description thereof will be omitted. A circulation system such as a pump is omitted in the drawings (the same applies to FIGS. 2 to 4).

A characteristic of the coating apparatus of FIG. 1 is that a cylindrical convex portion 3 is provided on the inner bottom wall 2a of the coating tank 2. A hollow portion 3a is formed inside the convex portion 3.

That is, as shown in FIG. 1 (b), the handle 5a of the lid 5 is provided with an opening 7, and the hollow portion 4c is an open system. The diameter of the hollow portion 4c is slightly larger than the outer diameter of the convex portion 3 so that the inner peripheral surface 4d of the basic drum 4 and the outer peripheral surface 3b of the convex portion 3 do not come into contact with each other when the base drum 4 is immersed. Has become.
In this state, when the substrate drum 4 is immersed in the coating liquid 1 with the opening 4b facing downward, the air in the hollow portion 4c is pushed out into the atmosphere as shown by arrow A.

With such a coating apparatus, the advantages of the conventional overflow-type coating apparatus can be fully enjoyed. That is, the height of the coating liquid surface is kept constant even when the substrate drum 4 is dipped, and therefore, the dry matter is not generated on the inner peripheral surface 2b of the coating tank side wall, and the frequency of occurrence of foreign matter defects is remarkable. The coating liquid 1 can be significantly reduced, and the change and deterioration of the components of the coating liquid 1 can be suppressed. Therefore, the productivity of coating can be improved, the waste of raw materials can be prevented, and the cost can be reduced.

Moreover, it should be noted that the presence of the convex portions 3 can reduce the amount of the coating liquid 1 required for coating. That is, conventionally, as shown in FIG. 9, it is necessary to fill the coating tank 2 and store a sufficient amount of the coating solution in the circulation system such as the tank 12. Was needed.

On the other hand, in the present invention, by providing the convex portion 3, the coating liquid 1 is excluded by the volume of the convex portion 3, and the amount of the coating liquid required to fill the coating tank is greatly reduced. . Moreover, as the amount of coating liquid contained in the coating tank decreases,
The amount of liquid in the circulation system is small, and the required amount of coating liquid is greatly reduced as a whole. Also, with the decrease of the coating amount,
The pump can be downsized by reducing the circulating amount (speed) of the coating liquid, and the filtering area of the filter can also be reduced.

By reducing the required amount of coating liquid and downsizing the device,
It is possible to reduce the cost of raw materials and the like, and even when the coating liquid finally reaches the usage limit, the amount of coating liquid to be discarded and the amount of replacement are small, which is also advantageous in preventing waste of raw materials. is there.

As described above, according to the present invention, it is possible to sufficiently enjoy the advantages of the conventional overflow method and reduce the required amount of the coating liquid.

FIG. 2 is a sectional view showing another coating device.

In this example, the height of the convex portion 13 is higher than that of the liquid surface 1a. Others are the same as those of the coating apparatus of FIG. In addition,
13a is a hollow portion, and 13b is an outer peripheral surface of the convex portion.

FIG. 3 is a sectional view showing still another coating device.

In this example, a cylindrical convex portion 23 having an opening 23c is provided above. The upper end of the convex portion 23 is higher than the liquid surface position 1a so that the coating liquid 1 does not flow into the space 23a. Note that 23b is the outer peripheral surface of the convex portion.

FIG. 4 is a sectional view showing still another coating device.

In this example, instead of the opening 7 being provided in the handle 5a,
It is provided on the bottom surface 2c of the coating tank, and when the substrate drum is dipped, air is discharged from the opening 7 as shown by arrow B.
Others are the same as the example of FIG.

The present invention is considered to be particularly effective when applied to a pigment-dispersed coating liquid such as a coating liquid for forming a carrier generation tank. A single-layer photosensitive layer containing both a granular carrier generating substance and a carrier transporting substance also corresponds to this. Because these coating liquids are usually pigment dispersion systems in which granular pigments are dispersed in the liquid, many of the pigments have a crystal form that is easily changed, and viscosity changes due to circulation,
This is because the influence of the change in the crystal shape of the pigment is large. Therefore, it is considered to be advantageous in terms of cost if the coating liquid amount and the circulating amount of the coating liquid are reduced by the coating device of the present invention.

5 to 7 each show an example of an electrophotographic photosensitive member which is layered by the coating apparatus of the present invention.

In the photoconductor of FIG. 5, a carrier generating layer 31 is provided as a first layer on a conductive substrate 30, and a cap generating layer 31 is provided.
A carrier transport layer 32 is provided as a second layer on the above. The photoreceptor shown in FIG. 6 is the first when viewed from the side of the conductive substrate 30.
A carrier transporting layer 32 as a layer and a carrier generating layer 31 as a second layer are sequentially laminated. The photoconductor of FIG. 7 has, as the first layer, a photosensitive layer 33 having a single layer structure containing both a carrier generating substance and a carrier transporting substance.

Of course, the number and types of coating layers applied and formed by the coating apparatus of the present invention are not limited to the examples shown in FIGS. It can be set freely according to the design intent.

For example, when viewed from the side of the conductive substrate, the first layer and the second layer are the undercoat layer, the photosensitive layer having a single-layer structure, the photosensitive layer having a single-layer structure, the protective layer, the first layer, the The second layer and the third layer are an undercoat layer, a carrier transport layer, a carrier generation layer, a carrier generation layer, a carrier transport layer, a protective tank, a first layer, a second layer, a third layer, and a third layer, respectively. Examples of the four layers include an undercoat layer, a carrier generation layer, a carrier transport layer and a protective layer, or an undercoat layer, a carrier transport layer, a carrier generation layer and a protective layer.

Subbing layer is acrylic, methacrylic, vinyl chloride,
Vinyl acetate type, epoxy type, polyurethane type, phenol type, polyester type, alkyd type, polycarbonate type, silicon type, melamine type, vinyl chloride / vinyl acetate copolymer, vinyl chloride / vinyl acetate / maleic anhydride copolymer, etc. It can be formed of various resins.

The carrier generation layer is, for example, a monoazo dye, a disazo dye,
Azo dyes such as trisazo dyes, perylene anhydride,
Perylene dyes such as perylene imide, indigo dyes such as indigo and thioindigo, polycyclic quinones such as anthraquinone, pyrenequinone and flapanthurones, quinacridone dyes, bisbenzimidazole dyes, indathron dyes, squarylium dyes Dyes, phthalocyanine-based pigments such as metal phthalocyanines, metal-free phthalocyanines, pyrylium salt dyes, eutectic complexes formed from thiapyrylium salt dyes and polycarbonates, and other various known carrier-generating substances together with a suitable binder resin and, if necessary, a carrier-transporting substance. It can be formed by dissolving or dispersing in a solvent and applying.

Further, the carrier transport layer is, for example, an electron-accepting substance such as trinitrofluorenone or tetranitrofluorenone that easily transports an electron, and a polymer having a heterocyclic compound represented by poly-N-vinylcarbazole in a side chain, triazole. Derivatives, oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives, polyarylalkane derivatives, phenylenediamine derivatives, hydrazone derivatives, amino-substituted chalcone derivatives, triarylamine derivatives, carbazole derivatives, stilbene derivatives, phenothiazine derivatives, etc. It can be formed by dissolving a carrier transporting material that is easy to transport together with a suitable binder resin in a solvent, coating and drying.

The photosensitive layer having a single-layer structure can be formed by dissolving or dispersing the above-mentioned carrier-generating substance in a solvent together with an appropriate carrier-transporting substance and a binder resin, and coating the solution.

Examples of the binder resin include polycarbonate, polyester, methacrylic resin, acrylic resin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate, styrene-based copolymer resin (for example, styrene-butadiene copolymer, styrene-methyl methacrylate copolymer). Polymer), acrylonitrile-based copolymer resin (for example, vinylidene chloride-acrylonitrile copolymer, etc.), vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin , Phenol resin (for example, phenol-formaldehyde resin, m-cresol-formaldehyde resin, etc.), styrene-alkyd resin, poly-N
Film-forming high molecular weight polymers such as vinylcarbazole, polyvinyl butyral and polyvinyl formal are preferred.

Further, the protective layer is polyurethane, polyethylene, polypropylene as the carrier transporting substance and binder resin,
Acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, epoxy resin, phenol resin, polyester resin, polycarbonate resin, silicone resin, melamine resin, etc., and copolymers containing two or more of these repeating units. It can be formed of resin or the like.

As the solvent used in forming the carrier transport layer, the carrier generation layer and the like, acetone, methyl ethyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,1,2-trichloroethane. , 1,1,2,2-tetrachloroethane, 1,1,2-trichloropropane, 1,1,2,2-tetrachloropropane, 1,2,3-trichloropropane, 1,1,2
-Trichlorobutane, 1,2,3,4-tetrachlorobutane,
Tetrahydrofuran, monochlorobenzene, dichlorobenzene, dioxane, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosolve acetate, n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N , N-dimethylformamide and the like.

The solvent for dissolving the carrier-transporting substance and the binder resin to form the coating solution is selected so that they can be uniformly dissolved, but the boiling point (bp) is 80 ° C to 15 ° C.
It is preferably 0 ° C, more preferably 90 ° C to 120 ° C. If the boiling point is less than 80 ° C., the drying is too fast to cause dew condensation and brushing is likely to occur, and the drying is too fast to perform leveling, and a smooth photosensitive layer cannot be easily obtained. Also, 150 ℃
If it exceeds the range, liquid dripping and uneven application are likely to occur. In particular,
Dichloromethane, 1,2-dichloroethane (bp = 83.5
℃), 1,1,2-trichloroethane (bp = 113.5 ℃), 1,4
-Dioxane (bp = 101.3 ° C), benzene (bp = 80.1
℃), toluene (bp = 110.6 ℃), o, m, p, -xylene (b
p = 138-144 ° C), tetrahydrofuran, dioxane,
Examples include monochlorobenzene. Also, the boiling point is 80 ℃
The boiling point can be adjusted by mixing the high-boiling point solvent and the low-boiling point solvent even if the solvent is not in the range of 150 ° C.

Further, as the solvent for forming the carrier generating layer and the photosensitive layer having a single-layer structure, the binder resin and the carrier transporting substance optionally contained are dissolved, and the carrier generating substance is preferably 2 μm or less, more preferably 1 μm or less. Those which can be dispersed in the form of fine particles and can provide a stable dispersion liquid, and when a lower carrier transport layer, an undercoat layer and the like are present, do not unduly dissolve or swell these are selected. In particular, among the above, toluene, chloroform, dichloromethane, 1,2-dichloroethane, 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane, tetrahydrofuran, monochlorobenzene, dioxane is a carrier generation layer. , And is a preferred solvent for both carrier transport layers.

The coating liquid used in the present invention may contain other substances besides the above. For example, if a siloxane-based compound is contained, it has the effect of smoothing the coated surface. Examples of the siloxane-based compound include dimethylpolysiloxane and methylphenylpolysiloxane.
The addition amount is preferably 1 to 10,000 ppm, and more preferably 10 to 1000 ppm, based on the total amount of the coating liquid.

In the photosensitive layer, an electron accepting substance such as succinic anhydride, maleic anhydride, or phthalic anhydride, preferably a carrier generating substance, is used for the purpose of reducing residual potential and memory.
It can be added at a rate of 0.1 to 100 parts by weight per 0 parts by weight. Further, in the photosensitive layer, if necessary, sensitivity improvement,
For the purpose of reducing memory, organic amines such as butylamine and diisobutylamine may be contained in a number of moles equal to or less than the number of moles of the carrier generating substance.

It is also possible to use the same binder resin and the same solvent for the carrier transport layer coating solution and the carrier generation layer coating solution to form a photoconductor, in which case the photoconductor productivity and performance are improved. Is further improved. That is,
If the same binder resin is used, the barrier between the carrier generation layer and the carrier transport layer will be reduced, and the carriers generated during light irradiation will be smoothly injected and transported into the carrier transport layer, and the sensitivity characteristics of the photoconductor, residual potential, memory characteristics, etc. Is also improved.

Furthermore, if the same binder resin, solvent and the like can be used in common, there is an advantage that the coating process is easy, accurate and high speed.

The shape and material of the conductive substrate are not particularly limited, but the same tubular shape is preferably used. Further, as the material, a metal plate, a metal drum, or a conductive polymer, a conductive compound such as indium oxide or a conductive thin layer made of a metal such as aluminum, palladium, or gold is applied, vapor deposition, by a means such as laminating. What is provided on a substrate such as paper or plastic film is used.

In forming the carrier generating layer and the photosensitive layer having a single-layer structure, more specifically, the following method is selected.

(A) A method of applying a solution in which a carrier-generating substance is dissolved in an appropriate solvent or a solution in which a binder is added and mixed and dissolved.

(B) A method in which a carrier-generating substance is made into fine particles in a dispersion medium by a ball mill, a homomixer, etc., and a binder is added as necessary to mix and disperse the resulting dispersion liquid.

In these methods, when the particles are dispersed under the action of ultrasonic waves, uniform dispersion becomes possible.

The coating liquid for forming the photosensitive layer, such as the photosensitive layer, the subbing layer and the protective layer, preferably has a viscosity within the range of 5 to 500 cp (centipoise) in order to more effectively exhibit the effects of the present invention,
More preferably, it is within the range of 10 to 300 cp. If the viscosity is less than the above range, the coating film tends to sag, and the lower part of the drum tends to have a thicker film, and if the viscosity is more than the above range, the viscosity of the coating liquid in the coating tank tends to be uneven, The coating film tends to have uneven thickness.

The thickness of the carrier transport layer after coating and drying is preferably in the range of 5 to 50 μm. If it is less than 5 μm, the desired charging ability (+
It may not be possible to obtain a sufficient carrier transport function, and if it exceeds 50 μm, the charging ability is too high (1000 V or more), the image quality is likely to be rough, the resolution is low, and the residual potential is large. easy. The amount of the carrier transporting material per 100 parts by weight of the binder resin should be in the range of 20 to 200 parts by weight, preferably 30 to 150 parts by weight. If it is less than 20 parts by weight, the carrier transporting function is low, the sensitivity is lowered and the residual potential is increased, and if it exceeds 200 parts by weight, the viscosity and surface tension are large and the coating processability tends to be deteriorated.

The thickness of the carrier generation layer after coating and drying is usually 0.05 to 10 μm. If it is less than 0.05 μm, the carrier generation ability is insufficient, and it is difficult to apply uniformly. If it exceeds 10 μm, the generated carrier is trapped, and conversely the sensitivity is apt to be lowered. The amount of the carrier-generating substance is 5 to 500 parts by weight, preferably 20 to 100 parts by weight, per 100 parts by weight of the binder resin. If the amount of the carrier-generating substance is less than 5 parts by weight, the carrier-generating ability is insufficient, and if it exceeds 500 parts by weight, the carrier is trapped, and the sensitivity is lowered and the memory is apt to occur. In addition, the amount of carrier transport substance that can be contained if necessary is
It is preferable that the amount is in the range of 20 to 200 parts by weight, preferably 30 to 150 parts by weight, per 100 parts by weight of the binder resin.

In the case of a single-layer photosensitive layer, the layer thickness after coating and drying is 10 to 50μ.
It is preferably m. When the layer thickness is smaller than the above range, the charging ability is low and the printing durability is poor. When the layer thickness is larger than the above range, the residual potential rises, and
It tends to be difficult to obtain sufficient transport capacity.

The protective layer provided on the surface of the photoreceptor preferably has a layer thickness of 0.01 to 1 μm. The layer thickness of the undercoat layer (or intermediate layer, barrier layer, adhesive layer, etc.) provided between the photosensitive layer and the conductive substrate is preferably in the range of 0.01 to 2 μm.

The ratio of the diameter of the substrate drum to the outer diameter (diameter) of the cylindrical convex portion is preferably in the range of 100: 98 to 100: 50. As a result, it is considered that the volume of the convex portion becomes large enough to eliminate the coating liquid and reduce the required amount of the coating liquid, and in some cases, the base drum and the convex portion may not come into contact with each other.

Incidentally, in forming the photoreceptor constituent layer, blade coating,
You may use together coating methods, such as spray coating and spiral coating.

Hereinafter, examples of the present invention will be described more specifically, but the present invention is not limited thereto.

<Preparation of coating liquid> First, a coating liquid was prepared as follows.

Preparation of coating liquid for forming carrier generation layer 1,2-dichloroethane (manufactured by Kanto Chemical Co., Inc.) (boiling point 83.5 ° C) 1
In 00 ml, 5.0 g of polycarbonate (Panlite-L-1250, manufactured by Teijin Kasei) as a binder resin was dissolved. As a carrier-generating substance, 4.10-dibromoanthanthrone (10 g) was pulverized in a ball mill for 24 hours, added with the above solution, and dispersed in a ball mill for another 24 hours to give a viscosity of 160c.
A carrier generating layer forming coating liquid (dispersion liquid) of p was obtained.

Coating solution for forming carrier transport layer 1,2-dichloroethane (manufactured by Kanto Chemical Co., Ltd.) 1000 ml, polycarbonate (Panlite-L-
1250, manufactured by Teijin Chemicals Ltd.) and dissolved as a carrier transport material 1,1-bis (4-N, N-dibenzylamino-2)
-Methylphenyl) normal butane 100 g was dissolved to prepare a carrier transport layer forming coating solution.

<Coating Experiment> Example A coating experiment was conducted using the coating apparatus shown in FIG. Coating tank 2
Has a diameter of 240 mm and a height of 350 mm, and the convex portion 3 has a diameter of 19
The height was 0 mm and the height was 300 mm.

The above-mentioned carrier generating layer forming coating liquid and carrier transporting layer forming coating liquid are respectively housed in a coating tank, and a carrier generating layer and a carrier transporting layer are sequentially formed on a base drum to form a negative charge type electrophotographic image. 100 photoconductors were continuously manufactured. However, as the substrate drum, a 200 mmφ × 350 mm aluminum cylindrical conductive substrate was used.

Comparative Example Using the coating tank shown in FIG. 9 and under the same conditions as in Example,
100 negative photosensitive drums were continuously manufactured. However, the diameter of the coating layer was 240 mm and the height was 350 mm.

<Results> Example For the carrier generation layer, the total amount of the coating liquid was 10 l (6 l in the coating tank, 4 l in the pipe) at the beginning, and 11 in total, 11 in total.

Regarding the carrier transport layer, the total amount of the coating liquid was 10 liters (6 liters in the coating tank and 4 liters in the piping), and an additional 2 liters in total.

Out of 100 photoconductors, 98 were good products.

Comparative Example For the carrier generation layer, the total amount of the coating liquid required was 22 liters (16 liters in the coating tank and 6 liters in the pipe) at the beginning and an additional portion of 1 liter in total.

Regarding the carrier transport layer, the total amount of the coating liquid was 22 liters (16 liters in the coating tank and 6 liters in the piping) at the beginning and 2 liters in total, which was 24 liters in total.

Out of 100 photoconductors, 98 were good products.

<Coating device> Note that the pump capacity varies from 20 l / minl (comparative example) to 2 l.
It was possible to reduce the size to (Example). Further, the filtration area of the filter could be reduced from 13000 cm ² (Comparative Example) to 1300 cm ² .

As described above, according to the coating apparatus of the example, it is apparent that the required coating liquid amount can be suppressed to half or less, and the pump capacity and the filtration area of the filter can be reduced.

Although the present invention has been illustrated above, the embodiments of the present invention are not limited to the above-described embodiments, and various modifications can be made.

For example, the size, shape, position, etc. of the coating tank, the body to be coated, and the convex portion may be various.

F. Advantageous Effects of Invention According to the coating apparatus of the present invention, the cover is fitted into one end of the opening of the object to be coated, has a lid used to hold the object to be coated, and has an outer diameter smaller than the inner diameter of the object to be coated, Since the lid and / or the convex body is provided with an opening for degassing, the coating liquid is removed by the convex portion in the coating tank. The amount of coating liquid required to fill the coating tank can be reduced by the removed amount, and the amount of liquid in the circulation system can be reduced accordingly, greatly reducing the required amount of coating liquid. To do. Therefore, the cost of manufacturing the coating liquid can be reduced, and the pump can be downsized by reducing the circulating amount of the coating liquid, and the filtration area of the filter can be reduced.

Further, since a lid for holding the object to be coated is fitted in one end of the opening of the object to be coated having both ends opening, there is no defect that a portion where the coating liquid is not applied to the object to be coated. That is,
If you want to hold the side surface of the coated object,
After application, the work of holding again and applying again must be repeated, which is troublesome and inefficient.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention, in which FIG. 1 shows a coating device, FIG. 1A is a sectional view of a coating tank, and FIG. Sectional views showing a state in which the substrate drum is immersed, FIG. 2, FIG. 3, and FIG. 4 are sectional views showing other coating devices, respectively. 5, 6 and 7 are sectional views showing an example of the electrophotographic photosensitive member. FIG. 8 and FIG. 9 are sectional views showing a conventional coating apparatus, respectively. In the drawings, reference numerals 1 ... Coating liquids 1a, 1b, 1c ... Position of coating liquid surface 2 ... Coating tank 2a ... Coating tank bottom inner wall 2c ... Coating tank bottom surface 2d ... Coating tank side wall 2e ... Upper edge of coating tank side wall 3, 13, 23 ... Convex portion 3a, 13a ... Hollow portion 3b, 13b, 23b ... Outer peripheral surface of convex portion 4 ... Base drum 4b ... Opening 4c .. Hollow part 4d ... Inner peripheral surface of base drum 4e ... Outer peripheral surface of base drum 5 ... Lid 6 ... Receiving tray 7 ... Opening 9 ... Dry solid 23a ... Space.

Claims (1)

[Claims] 1. An upper edge portion of a side wall of the coating tank is coated with the coating solution by immersing a coating object having openings at both ends in a coating solution contained in a coating tank and lifting the coating object. A coating device in which a coating liquid overflowing beyond is recirculated into the coating tank, the lid being fitted into one end of an opening of the coating target and used for holding the coating target, and the coating target. An outer diameter smaller than an inner diameter of the coating tank, and a convex body provided upright in the coating tank, wherein an opening for degassing is formed in the lid and / or the convex body. Coating device.