JPH0221963A - Method and device for coating - Google Patents

Abstract

PURPOSE:To lower the concn. of the solvent vapor in a coating tank and to early dry a coated film so that the uniform coated film is formed by supplying gas to the inner space of an object to be coated of discharging the gas for the inner space for a prescribed period of time at the time of applying a coating liquid to the object to be coated. CONSTITUTION:The coating liquid 1 is discharged from a discharge port 27 and is admitted into a coating liquid tank 12 to form the coated film on the outer peripheral surface of a base body drum (object to be coated) 4 by driving of a coating liquid discharge pump 20A. A stop valve 65 is thereafter switched to an open state and a discharge pump 20A is driven for the prescribed period of time to discharge the air from a discharge pipe 21. As a result, the air is the hollow part 4c of the base body drum 4 is sucked from a suction port 21a like an arrow A and the pressure in the hollow part 4c is reduced. The solvent vapor of the coating liquid in a coating tank 32 is discharged through the hollow part 4c of the base body drum, the suction port 21a and the discharge pipe 21 to the outside as shown by the arrow A from all the directions on the bottom end side of the base body drum. The coated film is, therefore, dried early and the flocculation of the coating liquid component is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a coating method and apparatus, and for example, to a uniisopropylene coating 4J method and apparatus for coating and forming a photosensitive layer of an electrophotographic photoreceptor.

In recent years, attempts have been made to develop organic photoreceptors with high sensitivity and long durability by assigning carrier generation and carrier transport functions to different substances in the photosensitive layer of electrophotographic photoreceptors. is being done. In such so-called function-separated type electrophotographic photoreceptors, substances that exhibit each function can be selected from a wide range of materials, so it is relatively easy to produce electrophotographic photoreceptors with arbitrary characteristics. Is possible.

When coating and forming the photosensitive layer of such an electrophotographic photoreceptor, it is necessary to form a thin, uniform layer with high precision in order to maintain good sensitivity characteristics and prevent image defects such as density unevenness, thereby exhibiting good performance as a photoreceptor. It is necessary to apply a layer.

Conventionally, various coating methods such as dip coating, spray coating, spinner coating, wire bar coating, blade coating, and roller coating have been known as coating methods for the photosensitive layer of electrophotographic photoreceptors, but dip coating and spray coating are the main methods. Coating is used.

Among these, dip coating is often used to form a uniform coating on a cylindrical object (such as a conductive substrate).

FIG. 10 shows a coating device used for dip coating.

A predetermined coating liquid 1 is contained in the coating tank 32 . When applying the dip, the cylindrical conductive substrate (hereinafter sometimes referred to as a substrate drum) 4 is immersed in the coating liquid 1 with the first part 4b facing downward, and then the handle 5a of the lid 5 is gripped. The small tram 4 is pulled up at a predetermined speed. Base body 1: A lid 5 is attached to the upper end side opening 4f of the ram 4 via a sealing means 16 to prevent air leakage from the upper end side. When immersing the substrates 1, 4, and 4, the coating liquid 1 does not penetrate into the hollow section 4c due to the air filling the hollow section 4C in the substrate tray 4, so that the liquid level reaches position 1b. descend. Accordingly, in the area sandwiched between the outer circumferential surface 4c of the base drum 4 and the side wall inner circumferential surface 32b of the coating tank 32, the liquid level of the coating liquid rises to position 1a, and a predetermined height is raised on the outer circumferential surface 4e of the base drum. The coating liquid 1 is then applied to form a coating film.

However, in such a coating device, when the base drum 4 is pulled up by motor drive, the base drum 4 vibrates,
The coating film became non-uniform due to the influence of this vibration, resulting in uneven coating.

In order to solve this problem, a coating device as shown in FIG. 11 has been proposed.

In this coating device, a coating liquid discharge port 1 is provided on the bottom wall 32c of the coating tank.
7 and a coating liquid supply lower, and the base drum 4 is connected to the coating tank 3.
2. Fix it in place. Next, the liquid sending pump (Pin
) After 10 days, the coating liquid 1 in the tank 12 is filtered through the filter 3.
The coating liquid level is raised from position 1C shown by the dashed line to position 1a shown by the solid line.After this, the drain pump (Pout) 10A is driven to The coating liquid 1 is then discharged and flows into the tank 12. From this, the outer circumferential surface 4e of the base tram
A coating film is formed on top.

However, the above coating apparatus has the following problems.

That is, when coating the base drum while discharging the coating solution, the interior of the coating tank is filled with vapor from the electrophotographic photosensitive solution (coating solution), and the coating film remains in an atmosphere with high solvent vapor density for a long time. exposed to time. This causes aggregation of pigments, etc. in the coating film,
The coating film was uneven. This seems to be because the coating liquid applied to the substrate IS ram dries slowly due to the high solvent vapor density of the atmosphere, and the pigments coagulate in this coating liquid.

In particular, this was a problem because the container vapor was heavier than air and tended to accumulate at the bottom of the coating tank (near the surface of the coating liquid).

Object of the Invention An object of the present invention is to provide a coating device that can speed up the drying of a coating liquid applied to an object to be coated, and can prevent agglomeration of coating liquid components and non-uniformity of the coating film. It is.

21. Constitution of the Invention The present invention provides a method for discharging the coating liquid from the coating tank in a state in which a cylindrical object to be coated is immersed in the coating liquid stored in the coating tank. In the coating method of applying the coating liquid to the object to be coated, supplying gas to the inner space of the object to be coated or discharging the gas from the inner space for a predetermined period of time after applying the coating liquid to the object to be coated. The present invention relates to a coating method characterized by:

Further, the present invention provides a method for discharging the coating liquid from the coating tank while the cylindrical coating body is immersed in the coating liquid stored in the coating tank. a signal generating means for generating a signal corresponding to the time point when the coating liquid is applied to the object to be coated; Then, for a predetermined period of time [1 (j), gas is supplied to the inner space of the object to be coated, or gas is supplied from the inner space to I.
The present invention relates to a coating device characterized in that it has a gas supply or gas discharge means.

E, Example The present invention will be explained in detail below.

FIGS. 1(a), 2, and 3 are schematic partial cross-sections showing the coating apparatus, respectively, and illustrate each process of coating. The first part (b) is a sectional view taken along the line 11-Ib of the part 11] (a).

In the coating apparatus of this example, an exhaust pump 20A is installed outside the coating tank 32, and an exhaust pipe 21 is connected to this exhaust pump 20A. A through-hole 5b is provided in the lid 5, and an on-off valve 65 is provided at the end ◇:b of the exhaust pipe 21, and the tip thereof is inserted into the through-hole 5b. a rikikinutabontora l,
It faces the hollow part 4C.

The other points are similar to the coating device shown in FIG. 11, and the same functional members are designated by the same reference numerals and their explanation will be omitted.

First, as shown in FIG. 2, while the substrates 1-4 are immersed in the coating liquid 1, the exhaust pump 20A is stopped. At this time, the on-off valve 65 is in a closed state.

Next, as shown in FIG.
(Pout) is driven to discharge the coating liquid 1 from the coating liquid discharge port 17 and flow into the coating liquid tank 12 as shown by the arrow. The liquid level of the coating liquid decreases at a constant speed to position 1c, and a coating film is formed on the outer peripheral surface of the base drum.

After that, the on-off valve 65 is opened, and the exhaust pump 20
A is driven to exhaust air from the exhaust pipe 21 as shown by the arrow. From the intake port 21a, the base drum hollow part 4
The air inside C is sucked in as shown by arrow A, and the pressure inside the base drum hollow part 4c is reduced. This results in
As shown in FIG. 1(b), the coating liquid solvent fumes in the coating tank 32 are sucked into the substrate drum J and hollow portion 4C from all directions at the bottom end of the substrate drum as shown by arrows A, and are sucked into the substrate drum J and hollow portion 4C. 21 a, and 62 from the exhaust pipe 21.
It is discharged to the outside air like this. In this state, the base tram 4 is pulled up from inside the coating tank 32 and brought into the state shown in FIG. 3.

Next, the unfinished base tram is accommodated in the coating tank 32,
Fix it in the position shown in Figure 2. Then, as shown in FIG. 2, the coating liquid supply pump 10El is driven to supply the coating liquid 1 from the supply lower as shown by the arrow, thereby raising the level of the coating liquid to the height of the position 1a. At this time, the on-off valve 65 is in the closed state. As a result, the base drum 4 becomes immersed in the coating liquid 1, returning to the state shown in FIG. 2, and one cycle of the coating process is completed.

The base drum is raised and lowered using a ball screw or cylinder.

In the above explanation, the gas in the coating tank was sucked and the solvent vapor was discharged by the exhaust pump. Steam may be vented. In this case, the above-mentioned exhaust pipe becomes a blower pipe, and the intake port becomes a blower port.

Each operation described in -1- can be performed by manual switching. For example, as shown in FIG. 1(a), visually confirm that the coating on the base drum 4 is completed, and then
Switch A is turned on, and at this time, the on-off valve 2 is also manually opened to perform exhaust gas.

Further, it is also possible to provide a detection means in the coating device to detect that coating of the substrates J and 4 has been completed.

For example, as shown in FIG. 1(a) and FIG. 2, a flow meter (flow rate IT) 60 is installed in the flow path from the coating liquid outlet 17 to the tank 12 as shown by the dotted line. The amount of coating liquid to be discharged from the state shown in FIG.
When the total amount of the coating liquid flowing through reaches the above-mentioned set value, a signal is generated as shown by the dashed line. and,
A signal converter 61 converts this signal into a predetermined electrical signal,
Input to exhaust pump 20A. As a result, the exhaust pump 2OA is driven and exhaust is performed.

Further, when the operation of the coating liquid discharge pump IOA is completed, the exhaust pump 20A is driven to perform exhaustion and complete the entire process. At this time, for example, at the same time as the application liquid discharge pump IOA is stopped, a signal is generated as shown by the two-dot chain line, and is sent to the exhaust pump 20A via the necessary signal conversion means, and in response to this signal, the exhaust pump 20A It may be configured to drive.

Further, it is also possible to set in advance the driving distance of the coating liquid discharge pump IOA and the iJI pump 20A in the control means 64 such as a microcomputer. Then, according to the above program contents, a predetermined electric signal is sent to the coating liquid discharge pump IOA and the exhaust pump 20A as shown by the dashed line, and each pump is driven by this signal.

According to the coating method and coating apparatus of this example, the following effects can be achieved.

(a) After coating the coating liquid on the base drum, the base 1"
The solvent vapor in the coating tank is evacuated by the exhaust pump 20A until the end of the second application. Therefore, the solvent quickly evaporates from the coating film formed on the base drum.
The paint film dries quickly. Therefore, agglomeration of the coating liquid components can be prevented, a uniform coating film can be formed, and the coating yield can also be improved.

In particular, since the coating liquid for the carrier generation layer of an electrophotographic photoreceptor is a pigment dispersion system, it has a remarkable effect in preventing pigment aggregation.

(b) A through hole is provided in the lid that holds the base drum, an exhaust pipe is inserted and fixed into the through hole, and the intake port of this one-stroke pipe faces the hollow part of the base tram.

As a result, as shown in Figure 1(b), the entire lower end of the base drum can take in air uniformly, so there is no uneven air flow or stagnation, and the solvent vapor is uniformly exhausted. , there will be no uneven drying of the paint film.

(C) Since the exhaust pipe intake port faces the hollow portion of the base drum and does not come into contact with the coating liquid, the coating liquid does not enter the intake port. Therefore, the suction pressure can be maintained at a constant level without the risk of dry matter of the coating liquid being deposited on the suction port.

It is also necessary to clean the intake port.

(d) Since the bleed pipe is fixed, by raising and lowering the lid, housing, and ram by normal means, the exhaust pipe and the intake pipe can also be raised and lowered accordingly. . Therefore, an elevating device for the exhaust pipe is unnecessary, and the coating device can be simplified and downsized, which is particularly advantageous when there is not enough space to provide an elevating device for the exhaust pipe. Of course, there is no need to control the elevation of the tJtt air pipe.

Furthermore, there is no risk that the paint film formed on the outer peripheral surface of the base drum will come into contact with the exhaust pipe and the paint film will be damaged.

(C) Since the coating liquid is discharged from the coating tank by a metering pump to form a coating film, there is no effect of vibrations accompanying lifting of the substrate tram. Therefore, a uniform coating film can be formed.

(f) Photosensitive layer of electrophotographic photoreceptor (carrier generation layer, etc.)
When agglomeration occurs in the coating film, an agglomerated pattern appears on the copied image.

On the other hand, in this example, 62L has no such image defects and can provide a uniform image.

Actual image 1 piece λ FIGS. 4 and 5 are schematic partial cross-sectional views showing other coating devices, respectively, and illustrate each process in which coating is performed.

In the coating apparatus of this example, as in Example 1, solvent vapor is discharged from the hollow portion of the substrate tram, and also from the outer circumferential surface of the substrate drum.

That is, as shown in FIG. 4, the exhaust pipe 31 is
The exhaust pump 30A is connected to the standby state. At this point, the waiting position may be changed in various ways.

Thereafter, as shown in FIG. 5, the coating liquid is discharged to the outside of the coating tank, and then the exhaust pipe 31 is lowered by a driving means (not shown), and the intake port 31'a is held near the surface of the coating liquid. At the same time, the exhaust pump 30A is driven to exhaust the atmosphere inside the coating tank to the outside air as shown by arrow A. In this state, the base drum 4 that has been coated is pulled up. The exhaust pipe 31 can also be lifted up from the coating tank at the same time as the base drum 4 is lifted up, and in this case, the third
It will be in the state shown in the figure. Furthermore, when the base drum 4 is pulled up, the exhaust pipe 31 can be held in the coating tank to continue discharging the solvent vapor. In this case, it is necessary to prevent the exhaust pipe 31 from coming out of the coating tank until the next time the coating liquid is supplied into the coating tank.

It is further preferable that the exhaust pipe 31 has a length of three or more trees.

In the coating device of this example, after coating the coating liquid on the outer peripheral surface of the cylindrical drum, the exhaust pipe 21.
1. Solvent fumes are exhausted from both sides. Therefore, in addition to the above-mentioned effects (a), (b), (C), (e), and (f), the solvent vapor can be more efficiently exhausted to the outside of the coating tank. However, if the exhaust volume (exhaust speed) from the exhaust pipe 31 side is too large, there is a risk of disturbing the flow of air in the coating tank. Preferably, the amount is small.

- In the example described in 1, the air was exhausted from both the air pipes 21 and 31, but the air may be blown from the exhaust pipes 21 or 31, or from both.

In this example, as in Example 1, a flow meter 60 is installed in the coating liquid flow path.
A flow meter 60 may be provided to detect the discharge amount of the coating liquid, and a signal from the flow meter 60 may be used to drive the exhaust pump 20A.

If the distance between the coating liquid level and the exhaust pipe intake port 31a is shortened, solvent fumes tend to accumulate near the coating liquid level, so that exhaust can be performed more efficiently. This distance is preferably, for example, 20 cm or less, more preferably 10 cm or less, but may vary depending on the dimensions of the coating tank (displacement volume, number of exhaust pipes), etc.

6 to 8 each show an example of an electrophotographic photoreceptor on which layers are formed by the coating apparatus of the present invention.

In the photoreceptor shown in FIG. 6, a first
A carrier generation layer 42 is provided as a layer, and a carrier transport layer 43 is provided as a second layer on the carrier generation layer 42. The photoreceptor shown in FIG. 7 has a gear transport N43 as a first layer and a carrier generation layer 42 as a second layer stacked in this order when viewed from the conductive base 41 side. The photoreceptor shown in FIG. 8 has a photosensitive layer 44 having a single-layer structure containing both a carrier-generating substance and a carrier-transporting substance as a first layer.

Of course, the number and types of coating layers coated and formed by the coating apparatus of the present invention are not limited to the examples shown in Figures 6 to 8, nor are their compositions, functions, etc. can be freely set according to the design intention.

For example, when viewed from the conductive substrate side, the first layer and the second layer are an undercoat layer and a photosensitive layer with a single layer structure, the photosensitive layer with a single layer structure, and a protective layer. The second layer and the third layer are respectively an undercoat layer, a carrier transport layer, and a carrier generation layer; a carrier generation layer, a carrier transport layer, and a protective layer; the first layer, the second layer, the third layer, and the third layer. The four layers may each be 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.

The undercoat layer is acrylic, acrylic, vinyl chloride, vinyl acetate, epoxy, polyurethane, phenol, polyester, alkynd, polycarbonate, silicone, melamine, vinyl chloride-vinyl acetate copolymer. , vinyl chloride-vinyl acetate-maleic anhydride copolymer, and various other resins.

The carrier generation layer is made of, for example, a monoazo dye, a disazo dye,
Azo dyes such as trisazo dyes, perylenic anhydride,
perylene dyes such as perylenic acid imide, indigo dyes such as indigo and thioindigo, anth-4 laquinone,
Polycyclic quinones such as pyrenequinone and flavanmelones, quinacridone pigments, bisbenzimidazole pigments, induthrone pigments, squarelylium pigments, phthalocyanine pigments such as metal phthalocyanines and metal-free phthalocyanines, pyrylium salt pigments, and thiapyrylium salts. It can be formed by dissolving or dispersing various known carrier-generating substances, such as a eutectic complex formed from a dye and polycarbonate, in a co-solvent with a suitable binder resin and, if necessary, a carrier transport substance, and applying the solution. .

In addition, the carrier transport layer is made of an electron-accepting substance that easily transports electrons, such as I-linitrofluorenone or te-1-lanitrofluorenone, and a heterocyclic compound such as poly-N-vinylcarbazole is used as a side chain. E1 polymers, triazole derivatives, oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives, polyarylalkane derivatives, phenylenediamine derivatives, human'razone derivatives, amino-substituted chalcone derivatives, triarylamine derivatives, carbazole derivatives, stilbene derivatives, phenothiazine derivatives It can be formed by dissolving various known carrier transport materials that easily transport holes, such as, in a solvent together with a suitable paint resin, coating, and drying.

Further, a photosensitive layer having a single layer structure can be formed by dissolving or dispersing a carrier-generating substance such as those described in "2" in a solvent together with a suitable Toyaria transport substance and a binder resin, and coating the solution.

Examples of the above binder resin include polycarbonate, polyester, methacrylic resin, acrylic resin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate-1, styrene copolymer resin (e.g. styrene-butadiene copolymer, styrene-butadiene copolymer, Methyl methacrylate copolymer), acrylonitrile copolymer resin (
For example, vinylidene chloride-acrylonitrile copolymer, etc.)
, vinyl chloride-vinyl acetate copolymer, vinyl chloride vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-Al; Todd resin, phenol resin (e.g. phenol-formaldehyde resin RH1m-cresol-formaldepide resin etc.), Styrene-alkyd resin, poly N-vinyl rubadur, polyvinyl butyral,
Film-forming polymers such as polyvinyl formal are preferred.

In addition, the protective layer contains polyurethane, polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin as the carrier transporting substance and binder resin.
Vinyl acetate resin, epoxy resin, polyester resin, phenolic resin, polycarbonate resin, silicone resin,
It can be formed from a melamine resin or the like, or a copolymer resin containing two or more repeating units of these resins.

Solvents used in coating and forming the carrier transport layer, 4-Year regeneration layer, etc. include acetone, methyl ethyl ketone, cyclohexone, benzene, toluene, xylene, chloropol J1, dichloromethane, 1,2-dichloroethane, 1.12-1-rif 1 colethane, 1,1
, 2.2-tetrachloroethane, 1. ．． 1.2-1-dichloropropane, ■.

1.2.2-tetrachloropropane, 1,2.3 trichloropropane, 1,1.2-)dichlorobutane, 1,2
, 3.4-tetrachlorobutane, tetrahydrofuran,
Monochlorobenzene, dichlorobenzene, dioxane,
Methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methylcellosolve acetate, n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, 1-lyethylenediamine, NN dimethylbormamide, etc. can be mentioned.

Further, as a solvent for dissolving the carrier transport substance and the binder resin to form a coating liquid, a solvent is selected that can uniformly dissolve them, and a solvent with a boiling point (bp) of 80° is selected.
Preferably 90°C to 120°C
is more preferable. If the boiling point is less than 80° C., drying is too fast, resulting in dew condensation, which tends to cause brushing, and drying is too fast, making it impossible to level, making it difficult to obtain a smooth photosensitive layer. Furthermore, if the temperature exceeds 150°C, dripping and uneven coating are likely to occur. Specifically, dichloromethane, 1,2-dichloroethane (bp-83,5°C), I,L2-)dichloroethane (bp=113.5'C), 1,4-dioquit7(b])= 101.3°C), benzene (b p =80.1°C), toluene (b p =11
0.6'C), o, m, p-xylene (b p = 13
8-144'C), tetrahydrofuran, dioxane,
Examples include monochlorobenzene. Also, the boiling point is 80°
Even if the melt temperature is not within the range of 150°C to 150°C, the boiling point can be adjusted by mixing a boiling point solvent and a low boiling point solvent.

Also, -Toyaria generation layer,! As a solvent for forming a photosensitive layer having a 'j'+ layer structure, it dissolves the H-Inder resin and the -1-Year transport substance contained if necessary, and the carrier juice substance preferably has a particle size of 2 μm or less, more preferably is 11! C1, which can be dispersed in the form of fine particles with a size of less than m and can promote a stable dispersion, and the lower layer. In particular, among the above, toluene, chloroborum, cyclocolmecun,
12-dichloroethane, 1゜1.2-trichloroethane, 1,1.22-tetrachloroethane, tetrabitrofuran, dio:1-zan, -1-yaria generation layer, carrier transport layer It is a preferred solvent for both.

The coating liquid used in the present invention may contain other substances in addition to those mentioned above. For example, the inclusion of a siloxane compound has the effect of smoothing the coating surface. Examples of the siloxane compounds include dimethylpolysiloxane and methylphenylpolysiloxane. The amount added is preferably 1 to 10,000 ppm, more preferably 10 to 1,000 ppm based on the total amount of the coating liquid.

In addition, it is also possible to form a photoreceptor using the same binder resin and the same solvent, especially in the coating liquid for the carrier transport layer and the coating liquid for the carrier generation layer. In that case, the productivity and performance of the photoreceptor may be improved. This has the advantage of further improving the performance. That is,
If the same binder resin can be 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 to the carrier transport layer, which will improve the photoreceptor's sensitivity characteristics, residual potential, memory characteristics, etc. will also be improved.

Furthermore, if the same binder resin, solvent, etc. can be used in common, there is an advantage that the coating process becomes easier, more accurate, and faster.

The shape, material, etc. of the conductive substrate are not particularly limited, but a cylindrical shape is preferably used. In addition, the materials include metal plates, metal trams, conductive polymers,
Conductive compounds such as indium oxide or aluminum
, a conductive layer made of metal such as palladium, gold, etc. is provided on a substrate such as paper or plastic film by means such as coating, vapor deposition, lamination, etc.

More specifically, the following method is selected for forming the carrier generation layer and the photosensitive layer having a single layer structure.

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

(Note) A method in which a carrier-generating substance is made into fine particles in a dispersion medium using a ball mill, a bomb mixer, etc., and a binder is added as necessary to mix and disperse the obtained dispersion, and the resulting dispersion is applied.

Dispersing the particles under the action of ultrasound in these methods allows for homogeneous dispersion.

The coating liquid for forming photoreceptor constituent layers such as the photosensitive layer, undercoat layer, and protective layer preferably has a viscosity within the range of 5 to 500 cp (centivoise) in order to better achieve the effects of the present invention. More preferably, it is within the range of 10 to 300 cp. If the viscosity is lower than the above range, the coating film is likely to sag,
The lower part of the drum tends to be thicker than the upper part, and if it is larger than the above range, the viscosity of the coating liquid in the coating tank tends to become non-uniform (and 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. Further, the carrier generation layer after coating and drying usually has a thickness of 0.05 to 10 μm. In the case of a single-layer photosensitive layer, the layer thickness after coating and drying is 10~
Preferably, it is 50 μm.

The thickness of the protective layer provided on the surface of the photoreceptor is 0.01 to 1μ
It is preferable to set it within the range of m. Further, the thickness of the undercoat layer (or intermediate layer, barrier layer, adhesive layer, etc.) provided between the photosensitive layer and the conductive substrate is preferably within the range of 0.01 to 2 μm.

In coating and forming each photoreceptor constituent layer, coating methods such as blade coating, spray coating, and spiral coating may be used in combination.

Although specific experimental examples will be described below, the present invention is not limited thereto.

<Application? Night preparation> First, a coating liquid was prepared as follows.

Carrier raw 1,2-dichloroethane (manufactured by Kanto Kagaku Co., Ltd.) (boiling point 83.
5.0 g of polycarbonate (Panrai IL-1250, manufactured by Kijin Kasei Co., Ltd.) as a binder resin was dissolved in 100 mR (5°C).

In addition, 5 g of 4.10-dibromoanthrone as a toyaria-generating substance was ground in a ball mill for 24 hours, the above solution was added thereto, and dispersed for another 24 hours in a ball mill, and applied to form a carrier-generating layer with a viscosity of 100 cp. liquid(
A dispersion liquid) was obtained.

〈Coating experiment〉 n example- Experiments were conducted using the coating apparatus shown in FIGS. 1 to 3.

An outer diameter of 80 mm is placed in a coating tank with an inner diameter of 120 mm and a depth of 380 mm.
An aluminum cylindrical conductive base drum (cylinder) having a diameter of 360 mm and a length of 360 mm was fixed, and then a coating solution for forming a toyaria generation layer was placed in a coating tank using a coating solution supply pump. Next, the carrier generation layer forming coating liquid was drawn out from the bottom of the coating tank using a magnet pump (coating liquid discharge pump) and supplied to the tank 12 . At this time, the coating liquid was lowered at a rate of 600 mm/min, and the base drum remained fixed in the coating tank.

At the same time as discharging the coating liquid from the coating tank, the exhaust pump was driven to exhaust the atmosphere inside the coating tank. This displacement amount will be described later.

Next, the coated base drum was pulled out of the coating tank. Thereafter, the uncoated substrate I/ram was housed and fixed in the coating tank.

The above operation was repeated 100 times with various displacements of the exhaust pump. The results are shown in FIG. However, in the figure, the horizontal axis represents the displacement of the exhaust pump, and the vertical axis represents the length of the agglomerated coating film in the axial direction.

Further, a similar test was conducted using the coating apparatus shown in FIG. 11, and a comparative example was obtained (displacement amount: 0).

From FIG. 11, it can be seen that agglomeration decreases as the displacement increases.

Although the present invention has been illustrated above, the embodiments of the present invention are not limited to those described above, and various modifications can be made based on the technical idea of the present invention.

In addition, the shape, number, capacity, etc. of the coating tank, coating liquid supply pump, and coating liquid discharge pump can be changed in various ways.

The shape, dimensions, number, etc. of the exhaust pipe, intake port, exhaust pump, etc. can be changed in various ways. The same applies to the blower pipe, blower port, and blower pump.

The present invention is applicable to various coating devices.

According to the coating method and apparatus of the present invention, gas is supplied to the inner space of the cylindrical object for a predetermined period of time after the application liquid is applied to the object to be applied, or gas is supplied from the inner space. is being emitted. Therefore, the gas is discharged from the opening in the inner space of the object to be coated, or the gas is sucked into the opening, so that the solvent vapor is discharged to the outside of the coating tank by the pressure of the gas discharged from the opening in the inner space. Or it is sucked into the opening and discharged from the inner space. Therefore, the concentration of solvent vapor in the coating tank can be lowered, and the evaporation of the solvent from the coating liquid applied to the object to be coated can be accelerated. Therefore, the coating film dries quickly, prevents the coating liquid components from agglomerating in the coating film, and forms a uniform coating film.

In addition, since gas is supplied to or discharged from the inner space of the cylindrical object to be coated, the gas is uniformly discharged from the opening of the inner space, or the gas is discharged from the opening of the inner space. Gas is evenly sucked into the

Therefore, the coating solution solvent vapor is uniformly discharged, and uneven drying of the coating solution does not occur, making it possible to form a uniform coating film.

[Brief explanation of the drawing]

1 to 9 show embodiments of the present invention, FIG. 1(a) is a schematic partial sectional view showing the coating device in a state where coating has been completed, and FIG. 1(b) is the same figure. 2 is a schematic partial sectional view showing the coating device with the base drum immersed in the coating liquid; Figure 3 is a sectional view taken along the line Ib-Ib in (a); FIG. 4 is a schematic partial sectional view showing another coating device before coating, and FIG. 5 is a schematic partial sectional view showing another coating device after coating. Schematic part t shown
The 61st, 7th, and 8th side views are respectively the -
・Partial cross-sectional view showing an example. Part 9 is a graph showing the relationship between the displacement of the exhaust pump and the number of coating defects. FIGS. 10 and 11 are cross-sectional views showing conventional coating devices, respectively. In addition, in the symbols shown in the drawings, 1...Coating liquid 4...Base 1' Ram 7...Coating liquid supply port 10A.・・・・・・・・・Application? IQrJl output pump 1
0B...Coating liquid supply pump 17...
・・・・・・Coating liquid outlet 20A, 30A・・・Exhaust pump 21.3
1...Exhaust pipes 21a, 31a...
...Intake port 60...Flowmeter 61...Signal converter 64...Control means 65... ...It is an on-off valve.

Claims (1)

[Scope of Claims] 1. With a cylindrical object to be coated immersed in a coating liquid stored in a coating tank, the coating liquid is removed from the coating tank by discharging the coating liquid from the coating tank. In the coating method of applying the coating liquid to the object to be coated, the gas is supplied to the inner space of the object to be coated for a predetermined period of time after the application liquid is applied to the object to be coated, or the gas is discharged from the inner space. Application method. 2. Coating, in which the cylindrical object to be coated is immersed in a coating liquid stored in a coating tank, and the coating liquid is applied to the object by discharging the coating liquid from the coating tank. The apparatus includes a signal generating means for generating a signal corresponding to the time when the coating liquid is applied to the object to be coated, and a signal generating means for generating a signal corresponding to the time when the coating liquid is applied to the object to be coated; A coating device comprising a gas supply or gas discharge means for supplying gas to or discharging gas from the inner space of the coating body.