JP3240958B2 - Dip coating device and electrophotographic photoreceptor manufacturing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dip coating apparatus for forming a coating film on the surface of an object to be coated by a dip coating method, and
The present invention relates to a method for producing an electrophotographic photoreceptor in which a constituent layer of an electrophotographic photoreceptor is formed on a peripheral surface of a cylindrical substrate by a dip coating method.

[0002]

2. Description of the Related Art An electrophotographic photoreceptor is manufactured by applying a material (hereinafter simply referred to as a "coating solution") to be a photosensitive layer on a peripheral surface of a cylindrical conductive substrate. Fig. 6
Using a dip coating device 60 shown in (1), the cylindrical substrate is immersed in a dip coating tank 61 containing a coating liquid with the longitudinal direction of the cylindrical substrate vertical and immersed to a predetermined depth, and then pulled up.
A method is adopted in which the raised cylindrical substrate is stopped, the coating liquid on the peripheral surface is touch-dried, and then dried by a hot-air drier or the like to solidify the coating film.

[0003] In order to obtain uniformity of the coating film in the vertical direction of coating of the substrate, a quick-drying solvent is usually used as a solvent for the coating solution. By using a quick-drying solvent,
Although the coating solution can be solidified in a short time, film thickness / unevenness may occur even when a quick-drying solvent is used for the following reasons.

[0004] That is, particularly when a quick-drying solvent is used, the generation of the solvent vapor concentration increases, and the coating liquid level of the dip coating tank increases.
Solvent vapor radiated from the coating liquid receiving tray (flow pan) 62 and from the object to be coated itself increases the solvent vapor concentration in the upper part of the dip coating tank, and solidifies the coating liquid on the peripheral surface of the cylindrical substrate pulled up. The time required for this increases, and the coating film unevenness / sagging increases.

[0005] As a measure for avoiding such coating film unevenness / sagging, in order to reduce the solvent vapor concentration in the upper part of the dip coating tank, 1)
As described in JP-A-59-127049 and the like,
While the cylindrical substrate is immersed in the dip coating tank, air is sent from the outside to the vicinity of the coating liquid tray, and air accompanied by solvent vapor is discharged from the vicinity of the coating liquid tray, and the cylindrical substrate is removed from the dip coating tank. A method in which the solvent vapor concentration around the cylindrical substrate when pulled up is reduced in advance and the drying speed to the touch is accelerated. 2) As described in JP-A-3-151, etc. Equipped with solvent vapor outlet, ON
-Disclosed is a device connected to a forced exhaust device provided with an OFF mechanism to control the solvent vapor concentration around the cylindrical substrate when the cylindrical substrate is pulled up from the dip coating tank. Suppression is being done.

However, the former is effective for preventing the stagnation of the solvent vapor evaporating from the coating liquid surface of the dip coating tank, but the solvent generated from the coating film on the peripheral surface of the cylindrical substrate when the cylindrical substrate is pulled up. Since the vapor cannot be discharged, the concentration of the solvent vapor around the cylindrical substrate rises, causing unevenness / sagging of the coating film, making it difficult to make the coating film thickness uniform. Further, in the latter case, there is a delay in following the solvent vapor concentration around the cylindrical substrate due to the ON-OFF operation, and it is difficult to make the coating film thickness uniform, as described above.

In Japanese Patent Application Laid-Open No. 8-220786, a solvent vapor outlet is provided in a return pipe of a coating liquid receiving tray for collecting a circulating coating liquid at a position lower than the coating liquid surface of a dip coating tank to control the solvent vapor concentration. Methods have been proposed. However, ideal exhaustion is not always possible due to problems such as the shape of the entire dip coating apparatus in the case of multi-coating and the positional relationship between the plurality of dip coating tanks and the coating liquid receiving tray. That is, even if the solvent vapor concentration can be reduced to some extent, the solvent vapor concentration around each of the raised cylindrical substrates varies due to the positional relationship between the plurality of dip coating tanks and the coating liquid receiving tray. In addition, no sufficient effect was obtained in suppressing the film thickness unevenness / sagging between the cylindrical substrates or within one cylindrical substrate.

[0008]

As described above, in the dip coating apparatus, when the cylindrical substrate is immersed in the coating liquid in the dip coating tank and then pulled up from the coating liquid to form a coating film, the dip coating tank is used. Solvent vapor radiated from the surface of the coating liquid, the inside of the coating liquid receiving tray, and the object to be coated itself increases the solvent vapor concentration in the upper part of the dip coating tank. And unevenness / sagging of the film thickness easily occurs. Therefore, it is important to reduce the solvent vapor concentration in the upper part of the dip coating tank as an improvement measure.

An object of the present invention is to separate the solvent vapor generated in the coating liquid receiving tray from the solvent vapor radiated from the object to be coated, and to diffuse the solvent vapor diverged from the object to be pulled up after coating. By providing a dip coating apparatus capable of forming a coating film having a uniform film thickness without coating unevenness / sagging by reducing the solvent vapor concentration around the object to be coated,
Another object of the present invention is to provide an electrophotographic photoreceptor manufacturing apparatus capable of forming a uniform photosensitive layer without coating unevenness / drip.

[0010]

The object of the present invention is as follows.
Is achieved by That is, the present invention provides: (1) holding a coating solution containing a solvent and immersing an object to be coated;
ToCylindricalA dip coating tank and a dip coating tank provided on the outer periphery of the dip coating tank.
The coating liquid is supplied to the coated coating liquid tray and the dip coating tank.
Liquid feeding means, and the bottom of the dip coating tank by the liquid feeding means.
From the top of the dip coating tank
Overflows the liquid and collects the overflowing coating liquid in the coating liquid pan
Then, the coating solution is again dipped and coated by the liquid feeding means.
Dip coating that circulates the coating liquid by supplying it to the tank
In the apparatus, on the coating solution receiving trayendDip coating on the part
Has an opening larger than the outer circumference of the tankCircularLidImmersion
So that the dip coating tank and the opening of the lid are concentricProvided,
The outer diameter Dd (mm) of the dip coating tank and the opening diameter F of the lid
d (mm) has the following relationship, 1 <Fd / Dd ≦ 1.5 Fd-Dd ≧ 4 (mm)  The upper end of the dip coating tank is projected from the opening of the lid, and the coating is performed.
Flow solvent vapor from the liquid below the top of the coating tank
It is a dip coating device characterized by that.

(2 ) A cylindrical hood having an opening at both ends in the axial direction, having an inner diameter equal to or larger than the opening diameter of the lid, and having a communication hole provided on the outer periphery thereof for communication with the outside, The dip coating device according to ( 1 ), wherein the dip coating device is arranged so as to be concentric with the opening at an upper portion. ( 3 ) The dip coating device according to ( 2 ), wherein the communication hole is provided at a lower end portion of an outer periphery of the hood and / or a peripheral portion thereof.

( 4 ) The dip coating apparatus according to ( 2 ), wherein the communication hole is provided on the entire outer periphery of the hood. ( 5 ) The dip coating device according to ( 2 ), wherein the outer periphery of the hood is a mesh having an opening diameter of 10 μm to 1 mm. ( 6 ) A plurality of dip coating tanks, and the lid is provided with the same number of openings as the dip coating tanks (1) to ( 5 ).
The dip coating device according to any one of the above.

[0013]7) Solvent to be a constituent layer of electrophotographic photoreceptor
Holding a coating solution containing, and dipping a cylindrical substrate
A coating tank and a coating liquid receiver provided on the outer periphery of the dip coating tank
Dish, liquid feeding means for supplying a coating liquid to the dip coating tank,
The coating liquid is supplied from the bottom of the dip coating tank by the liquid feeding means.
Supply, overflowing the coating solution from the upper opening of the dip coating tank,
The overflowing coating solution is collected in a coating solution tray, and
The cloth liquid is supplied to the dip coating tank by the liquid feeding means.
By circulating the coating liquid, immersion in the dip coating tank
The raised cylindrical substrate is lifted and the structure of the electrophotographic photosensitive member is
In an electrophotographic photoreceptor manufacturing apparatus for forming a layer,
On the coating liquid panendLarger than the outer circumference of the dip coating tank
Has a nice openingCircularLid, The dip coating tank and the lid
So that the opening is concentricProvided,Of the dip coating tank
The outer diameter Dd (mm) and the opening diameter Fd (mm) of the lid are:
Has the following relationship, 1 <Fd / Dd ≦ 1.5 Fd-Dd ≧ 4 (mm)  The upper end of the dip coating tank protrudes from the opening of the lid,
The vapor of the solvent from the cloth liquid flows below the upper end of the coating tank.
An electrophotographic photoreceptor manufacturing apparatus characterized in that:.

( 8 ) A cylindrical hood having an opening at both ends in the axial direction, having an inner diameter equal to or larger than the opening diameter of the lid, and having a communication hole provided on the outer periphery thereof for communication with the outside, is provided with a hood of the opening of the lid. ( 8 ) The apparatus for manufacturing an electrophotographic photosensitive member according to ( 7 ), wherein the electrophotographic photosensitive member is arranged so as to be concentric with the opening. ( 9 ) The apparatus for manufacturing an electrophotographic photosensitive member according to ( 8 ), wherein the communication hole is provided at a lower end portion of an outer periphery of the hood and / or a peripheral portion thereof.

( 10 ) The apparatus for manufacturing an electrophotographic photosensitive member according to ( 8 ), wherein the communication hole is provided on the entire outer periphery of the hood. ( 11 ) The apparatus for manufacturing an electrophotographic photosensitive member according to ( 8 ), wherein the outer periphery of the hood is a mesh having an opening diameter of 10 μm to 1 mm. ( 12 ) The apparatus for producing an electrophotographic photosensitive member according to any one of ( 7 ) to (15), further including a plurality of dip coating tanks.

Conventionally, there is no disclosure of a technique in which the height of a coating liquid surface (overflow surface) of a dip coating tank is particularly specified, and generally has an opening provided on the overflow surface and an upper portion of a coating liquid receiving tray. Almost the same height as the lid,
Alternatively, the lid is set at a slightly higher position. On the other hand, according to the present invention, as a means for reducing the solvent vapor concentration on the dip coating tank, the coating liquid surface (overflow surface) of the dip coating tank is raised from the wall of the coating liquid receiving tray (flow pan) for receiving the overflowed liquid. high, characterized in that protrudes from the cover having an opening provided in an end portion on the coating liquid pan. With such a configuration, an escape path for the solvent vapor generated from the coating liquid surface of the dip coating tank or the object to be coated can be secured, and the solvent concentration in the upper part of the dip coating tank can be reduced. In other words, the solvent vapor of the coating liquid is generally heavier than air, and the solvent vapor generated from the surface of the coating liquid in the dip coating tank or the object to be coated itself flows out in the direction of the escape route below if there is an escape route, and the solvent vapor flows upward in the dip coating tank. The solvent concentration is reduced without the vapor remaining. Also, even if the solvent vapor generated in the coating liquid receiving tray is going to rise upward due to the flow of external air, etc., it is blocked by the lid on the coating liquid receiving tray, and does not rise to the top of the dip coating tank. A low concentration of the solvent in the upper part of the tank can be secured. As a result, an object to be coated having a uniform thickness without coating unevenness, for example, an electrophotographic photosensitive member can be manufactured.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described. FIG. 1 shows a schematic configuration diagram of a dip coating apparatus 10 of the present invention. In FIG. 1, reference numeral 11 denotes a dip coating tank for holding a coating liquid and immersing an object to be coated, 12 a flow pan (coating liquid receiving tray) provided on the outer periphery of the dip coating tank 11, and further includes a dip coating apparatus. 10 is a dip coating tank 11
And a liquid supply means P such as a pump for supplying a coating liquid to the apparatus. In the present embodiment, the coating liquid collected by the flow pan 12 is collected, the concentration, viscosity, etc. of the coating liquid are adjusted to prepare the coating liquid recovery tank 15 for the next circulation, and the liquid feeding means P
A filter F for removing impurities in the coating solution is provided downstream of the filter. The coating liquid in the coating liquid recovery tank 15 is supplied from the bottom of the dip coating tank 11 through the filter F by the liquid feeding means P. In the dip coating tank 11, the coating liquid overflows from the upper end opening, and the overflowing coating liquid is collected by the flow pan 12 and sent to the coating liquid recovery tank 15 through the return pipe 13. The recovered coating liquid is again supplied to the dip coating tank 11 by the liquid feeding means P and circulates in the dip coating apparatus 10 as described above. In the dip coating apparatus 10, a lid 14 having an opening larger than the outer periphery of the dip coating tank 11 is provided above the flow pan 12, and the top of the dip coating tank 11 is
4 protrudes from the opening.

In the present invention, the lid 14 of the flow pan 12
The height (Dh) of the upper end of the dip coating tank 11 from the surface is 5
mm or more, more preferably 10 m
m to 50 mm, more preferably 10 mm to 20 m
m. If the height (Dh) of the upper end of the dip coating tank 11 from the surface of the lid 14 of the flow pan 12 is less than 5 mm, it is not preferable because the solvent vapor on the dip coating tank 11 cannot be effectively released.

The dip coating tank 11 is cylindrical, the opening of the lid 14 of the flow pan 12 is circular, and the dip coating tank 1
1 and the opening of the lid 14 are arranged so as to be concentric circles.
Is the opening diameter of Fd (mm), and the outer diameter of the dip coating tank 11 is Dd.
(Mm), it is more effective to satisfy the following relational expression. 1 <Fd / Dd ≦ 1.5 Fd−Dd ≧ 4 (mm)

In order to make the dip coating tank 11 protrude above the lid 14, the opening diameter Fd of the lid 14 must be larger than the outer diameter Dd of the dip coating tank 11 (1 <Fd / Dd). The solvent vapor generated in the flow pan 12 is
4, the efficiency of separation is reduced, and the solvent vapor penetrates to the top of the dip coating tank 11, and the object of the present invention is not achieved. Therefore, it is the onset The Fd / Dd than 1.5
In the bright is mandatory, it is good Mashiku 1.4 or less.

Further, since the coating liquid overflowing from the upper end opening of the dip coating tank 11 is collected by the flow pan 12, the overflowing coating liquid is applied between the dip coating tank 11 and the opening of the lid 14. A certain gap is required for the liquid to flow into the flow pan 12, and this gap should be at least 2 mm or more, ie, Fd-Dd ≧ 4 (depending on the viscosity of the coating liquid and the degree of overflow). it is essential is mm).
As this relational expression, Fd−Dd ≧ 10 (mm)
If the value of Fd-Dd is too small, the coating liquid that overflows from the upper end opening of the dip coating tank 11 does not flow into the flow pan 12 but flows out onto the lid 14 and flows to the circulation system of the coating liquid. Cause trouble .

The dip coating tank 11 may have any size, such as an inner diameter and a length, as long as it can immerse the object to be coated. However, in coating the constituent layers of the electrophotographic photosensitive member, Normal inner diameter 40-260mm, length 350-60
Those having a thickness of about 0 mm are used. In addition, since the preferable conditions of the present invention are defined by the outer diameter Dd of the dip coating tank 11 as described above, the thickness of the cylinder of the dip coating tank 11 also becomes a problem in relation to the inner diameter. A sufficient thickness is required to hold the coating solution, and preferably in the range of 0.5 to 5 mm.

In the present invention, it is preferable to use a hood 16 for shielding the outside air in order to prevent unevenness of the coating film due to the influence of the outside air. FIG. 2 is a schematic configuration diagram of the dip coating device 20 provided with the hood 16. Food 16
Has a cylindrical shape with both ends opened in the axial direction, and has an inner diameter equal to or larger than the opening diameter of the lid 14. Food 1
Numeral 6 is arranged so as to be substantially concentric with the opening of the lid 14 and surrounds the projecting dip coating tank 11. In order to provide the hood 16 with an effect of sufficiently shielding the outside air, the dip coating tank 1 from the lid 14 of the flow pan 12
1. The hood 16 needs to protrude to a position sufficiently higher than the height (Dh) of the upper end, and when the length of the hood 16 in the axial direction is Hl, Hl-Dh ≧ 50 (m
m), and Hl-Dh ≧ 100 (m
m) is more preferable.

FIG. 3A is a perspective view showing an example of the hood 16. At the lower end of the outer periphery of the hood 16, a hood 16
As means for reducing the concentration of the solvent vapor inside, a communication hole 19 communicating with the outside is provided. The communication hole 19 may be provided slightly above the lower end of the outer periphery of the hood 16 (peripheral portion of the lower end), or may be provided on the entire outer periphery. The solvent vapor of the coating liquid is usually heavier than air, and the generated solvent vapor flows downward.
Preferably, it is provided at the lower end of the outer periphery of 6 and / or at the periphery thereof. FIG. 3B is a perspective view illustrating another example of the hood 16. The outer periphery of the hood 16 is formed in a mesh shape, and the opening of the mesh plays the role of the communication hole 19 in the example of FIG. The mesh preferably has an opening diameter in the range of 10 μm to 1 mm in order to sufficiently shield outside air from the hood 16 and sufficiently reduce the solvent vapor concentration in the hood 16. .

In the present invention, the dip coating tank 11
It is also a preferable embodiment that a plurality of objects to be coated can be processed simultaneously. Productivity can be improved by simultaneously processing a large number of objects to be coated. FIG. 4 is a perspective view showing an example of a dip coating apparatus 40 having eight dip coating tanks 11 and capable of simultaneously processing eight objects to be coated, and FIG. 5 is a sectional view thereof. The dip coating apparatus 40 includes a dip coating tank 1 above the flow pan 12.
A lid 14 having eight openings 18 larger than the outer periphery of the lid 1 is provided.
More protruding. In this embodiment, the dip coating device 40 is a mesh-shaped hood 16 shown in FIG.
Is provided above the opening 18 of each of the lids 14. In FIG. 6, the hood 16a above the opening 18 on the left end is shown in a detached state so that the state of the dip coating tank 11a inside the hood 16a can be seen. Of course, when using the dip coating apparatus 30, the hood 16a has the opening 1
8 is installed in contact with the lid 14. The coating liquid sent by the liquid feeding means P is supplied from the bottom of the eight dip coating tanks 11 through the pipes 17, and the coating liquid overflows from the upper openings of the eight dip coating tanks 11. A flow pan 12 for collecting all the overflowing coating liquid is provided on the outer periphery of the eight dip coating tanks 11, and the collected coating liquid is sent to a coating liquid collecting layer (not shown) through a return pipe 13. To prepare for the next cycle. In the dip coating apparatus 40 having such a plurality of dip coating tanks 11, the various conditions and the like are the same as in the case of the single tank.

The dip coating apparatus of the present invention is particularly preferably used for an electrophotographic photoreceptor as described above, but can be applied to any object to be coated by other dip coating methods. The dip coating apparatus of the present invention is an effective coating apparatus when a quick-drying solvent is used and a coating film having a uniform coating thickness is desired, and is particularly suitable for a long object to be coated.

Next, the case where the above-described dip coating apparatus is used as an apparatus for manufacturing an electrophotographic photosensitive member will be described. An electrophotographic photoreceptor is provided with a photosensitive coating (photosensitive layer) on a substrate. Depending on the type of the photosensitive layer, a single layer containing a charge generating substance and a charge transporting substance in one photosensitive layer is used. When,
There is a laminated type in which the photosensitive layer is functionally separated into a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance. In some cases, an interference prevention layer and an undercoat layer are provided between layers. As an apparatus for manufacturing an electrophotographic photoreceptor of the present invention,
The present invention can be applied to the case where any of these layers of the electrophotographic photosensitive member is formed. In particular, the apparatus for producing an electrophotographic photoreceptor of the present invention is suitable for obtaining a thick film layer of 20 μm or more, such as a charge transport layer in a laminated electrophotographic photoreceptor or a photosensitive layer in a single-layer electrophotographic photoreceptor. It has a remarkable effect on film formation and can provide an excellent electrophotographic photosensitive member. Hereinafter, the configuration of the electrophotographic photosensitive member will be described.

As the substrate, aluminum, stainless steel,
Metal materials such as nickel, polyethylene terephthalate,
Examples thereof include a method in which a conductive material is dispersed as a conductive treatment in a polymer material such as polybutylene terephthalate, polypropylene, nylon, polystyrene, or phenol resin, or an insulating material such as hard paper, a method of laminating a metal foil, and a method of vapor deposition of a metal. Further, the shape of the substrate is cylindrical, usually having a diameter of 10 to 2 mm.
00 mmφ, length 200 to 500 mm.

The constituent layers of the electrophotographic photoreceptor provided on the substrate will be described below separately for a case where the photosensitive layer is a laminated type and a case where the photosensitive layer is a single layer type. 1. In the case of a laminated type, an undercoat layer is usually provided on the base. As the undercoat layer, various resins and zirconium compounds such as acrylic, mechacrylic, vinyl chloride, vinyl acetate, epoxy, polyurethane, phenol, polyester, alkyd, polycarbonate, silicon, melamine, etc. Examples of the above resins containing a titanium compound, a silane coupling agent, and the like. The method for forming the coating film of the undercoat layer will be described later.

An anti-interference layer may be provided as an undercoat layer or on a substrate separately from the undercoat layer for the purpose of preventing interference of a laser light source. Examples of the interference prevention layer include a layer in which a metal oxide such as titanium oxide is dispersed in a resin, a layer in which an organic pigment or the like is dispersed, and the like. The method for forming the coating of the interference prevention layer will be described later.

A charge generation layer and a charge transport layer are provided on the undercoat layer or the interference prevention layer. Either of these layers may be placed on the upper side. As the charge generating substance contained in the charge transport layer, azo pigments, disazo pigments, quinone pigments, quinocyanine pigments, perylene pigments,
Indigo pigments, bisbenzimidazole pigments, phthalocyanine pigments, quinacridone pigments, pyrylium salts, azurenium salts, tricrystalline selenium, and the like.

The charge transporting substance contained in the charge transporting layer includes polyaromatic compounds such as anthracene, pyrene, phenanthrene, and coronene in the main chain or side chain, or indole, carbazole, oxazole, isoxazole, thiazole, imidazole, or the like. Examples thereof include compounds having a skeleton of a nitrogen-containing cyclic compound such as pyrazole, oxadiazole, pyrazoline, hyadiazole, and triazole, and hole transport substances such as hydrazone compounds.

Examples of the binder resin for forming the coating film of the charge generation layer and the charge transport layer include polycarbonate, polyarylate, polystyrene, polymethacrylates, styrene-methyl methacrylate copolymer, polyester, and styrene-acrylonitrile copolymer. , Polysulfone, polyvinyl acetate, polyacrylonitrile, polyvinyl butyral, polyvinyl pyrrolidone, methyl cellulose, hydroxymethyl cellulose, cellulose esters and the like.

A method for forming a coating film of the interference preventing layer, the undercoat layer, the charge generation layer, and the charge transport layer will be described. Each of these layers is obtained by dissolving or dispersing the above components in an appropriate solvent,
Apply sequentially. As the coating solution solvent (solvent), a solvent having a high volatility and a vapor density higher than that of air is preferably used. For example, n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, N, N-dimethylformamide,
Acetone, methyl ethyl ketone, cyclohexanone, benzene, 4-methoxy-4-methylpentanone, dimethoxymethane, dimethoxyethane, 2,4-pentadione, anisole, methyl 3-oxobutanoate, monochlorobenzene, toluene, xylene, chloroform, 1,
2-dichloroethane, dichloromethane, tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, 1-butanol, ethyl acetate, butyl acetate,
Examples include dimethyl sulfoxide, methyl cellosolve, ethyl cellosolve, methyl cellosolve, and methyl cellosolve acetate.

In the present invention, the effect of the present invention is particularly exerted by using dichloromethane, tetrahydrofuran or the like which has a high dissolving power of the charge transporting substance and the binder resin and a high evaporation rate (quick drying). You. The viscosity of the coating solution is changed depending on the purpose of the film thickness, the coating speed and the like, but is preferably in the range of 100 to 600 mP · S.

Each coating solution as described above is charged into the dip coating tank 11 of the dip coating device 10, 20 or 40 shown in FIG. 1, FIG. 2 or FIG. , 40. Then, the substrate to be coated is immersed in the dip coating tank 11 with its longitudinal direction vertical, and is pulled up at a predetermined speed. Since the upper part of the dip coating tank 11 is kept at a low concentration of the solvent vapor due to the effect of the present invention, in the case of a coating solution using a quick-drying solvent, the coating solution dries immediately after being pulled up and touches. It becomes dry,
A uniform coating film is formed on the substrate surface without causing liquid dripping. In particular, when the dip coating apparatuses 20 and 40 shown in FIG. 2 or 4 provided with the hood 16 are used, the influence of the outside wind is reduced, the unevenness in the circumferential direction hardly occurs, and a very uniform coating film is formed on the substrate surface. Can be formed. Furthermore, a durable coating film can be obtained by drying with a hot air dryer or the like. In this way,
An electrophotographic photoreceptor can be manufactured by forming an undercoat layer, an interference prevention layer, a charge generation layer, and a charge transport layer.

The thickness of each layer is appropriately adjusted depending on the type of the solvent, the ratio of the solvent in the coating solution, the speed of lifting the object to be coated, and the like. The preferred range of the thickness of each layer is as follows. Undercoat layer: about 0.1 to 10 μm Interference prevention layer: about 1 to 30 μm Charge generation layer: about 0.05 to 1 μm Charge transport layer: about 10 to 30 μm Among these layers, a thick film layer is particularly provided. For the charge transport layer, it is preferable to use the dip coating apparatus of the present invention (electrophotographic photoreceptor manufacturing apparatus), but other layers are conventionally known ordinary dip coating apparatuses and other known coating apparatuses (for example, , A spray method, a bar coat method, etc.).

2. In the case of single-layer type In the case of producing a single-layer type electrophotographic photoreceptor, the coating solution for the photosensitive layer is prepared by mixing or dispersing a charge generating substance, a charge transporting substance, and a binder resin in a solvent. The charge generating substance, charge transporting substance, binder resin and solvent that can be used are the same as those used in the case of the laminated type. The above-mentioned undercoat layer and / or interference prevention layer may be provided in a single layer type, and the coating liquid is obtained by mixing the undercoat layer and / or interference prevention layer substance used in the case of the laminate type with a solvent. To be mixed. The coating solution for the photosensitive layer and the coating solution for the undercoat layer provided as needed are coated on the substrate by the dip coating apparatuses 10, 20, and 40 in the same manner as in the case of the laminated type. Adjustment of the film thickness of the coating film, the preferable range of the thickness of the undercoat layer and the interference prevention layer is also the same as in the case of the laminated type.
It is about 40 μm.

[0039]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples. The compositions of the compounds and the coating solutions used in the following examples are as follows.

[0040]

Embedded image

[0041]

Embedded image

Coating solution A (undercoat layer) 20 parts by weight of zirconium compound of structural formula (1) 2 parts by weight of silane coupling agent of structural formula (2) 2 parts by weight of polyvinyl butyral resin of structural formula (3) 1-butanol 70 parts by weight The above materials were mixed and dissolved to obtain a coating liquid A.

Coating solution B (charge generation layer) Chlorgallium phthalocyanine 5 parts by weight Vinyl chloride-vinyl acetate copolymer of structural formula (6) 5 parts by weight 200 parts by weight of n-butyl acetate The dispersion obtained by dispersing with a used sand mill for 2 hours was used as a coating liquid B.

Coating Solution C-1 (Charge Transport Layer 1) Charge Transport Substance of Structural Formula (4) 1 part by weight Polycarbonate resin of Structural Formula (5) 1 part by weight Monochlorobenzene 2 parts by weight Tetrahydrofuran 4 parts by weight The above materials are mixed. The solution was designated as a coating solution C-1.

Coating solution C-2 (charge transport layer 2) 1 part by weight of charge transport material of structural formula (4) 1 part by weight of polycarbonate resin of structural formula (5) 1 part by weight of monochlorobenzene 6 parts by weight of dichloromethane 2 parts by weight of the above materials The solution was designated as a coating solution C-2.

Example 1 A coating solution A (undercoat layer) was applied to a 84 mmφ × 340 mmL cylindrical aluminum substrate having a surface roughness Ra of 0.18 by a wet honing treatment using a dip coating device (normal coating device). Coating is performed at a pulling rate such that the dry film thickness becomes 1.0 μm, air drying is performed for 2 minutes, and drying temperature is 150 ° C., 10
Dried for minutes. Then, the coating liquid B (charge generation layer) was dried using a dip coating device (normal coating device) to a dry film thickness of 0.2 μm.
m, and the film was dried at a drying temperature of 100 ° C. for 10 minutes. Further, the coating liquid C-1 (charge transport layer) was applied by using the dip coating apparatus 10 of FIG. 1 at a lifting speed such that the dry film thickness became 25 μm. The dip coating device 10 was set under the following conditions. The height of the upper end of the dip coating tank 11 from the surface of the lid 14 (hereinafter, referred to as
It is described as "Dh", and "+" is added before the numerical value for distinction from the comparative example described later): +10 mm. The outer diameter of the dip coating tank 11 (hereinafter, described as "Dd"): 110 mm.phi. 14 opening diameter (hereinafter referred to as “Fd”): 13
After that, the film was dried for 2 minutes at a drying temperature of 135 ° C. with a hot air drier for 2 minutes. Thus, an electrophotographic photosensitive member was manufactured.

Comparative Example 1 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the dip coating apparatus 60 shown in FIG. 6 was used under the following conditions when forming the charge transport layer. -The upper end of the dip coating tank 61 is lowered by 10 mm from the surface of the lid 64 (hereinafter, such a case of downing is indicated by adding "-" in front of the numerical value using the symbol Dh in the first embodiment. In this example, Dh: -10 m
m)-Outer diameter of the dip coating tank 61 (hereinafter "Dd" as in Example 1)
): 110 mmφ • Opening diameter of lid 64 (hereinafter, described as “Fd” as in Example 1): 130 mmφ

Example 2 A coating solution A (undercoat layer) was applied to a 30 mmφ × 360 mmL cylindrical aluminum substrate having a surface roughness Ra of 0.20 by wet honing using a dip coating device (normal coating device). Coating is performed at a pulling speed such that the dry film thickness becomes 1.0 μm, air drying is performed for 2 minutes, drying temperature is 150 ° C.
Dried for minutes. Then, the coating liquid B (charge generation layer) was dried using a dip coating device (normal coating device) to a dry film thickness of 0.2 μm.
m, and the film was dried at a drying temperature of 100 ° C. for 10 minutes. Further, the coating liquid C-2 (charge transport layer) was applied by using the dip coating apparatus 10 of FIG. 1 at a lifting speed such that the dry film thickness became 24 μm. The dip coating device 10 was set under the following conditions.・ Dh: +20 mm ・ Dd: 100 mmφ ・ Fd: 130 mmφ Thereafter, the substrate was dried for 2 minutes by natural drying, and further dried by a hot air dryer at 115 ° C. for 40 minutes. Thus, an electrophotographic photosensitive member was manufactured.

Comparative Example 2 An electrophotographic photosensitive member was produced in the same manner as in Example 2 except that the dip coating apparatus 60 shown in FIG. 6 was used under the following conditions when forming the charge transport layer. · Dh: ± 0 mm (the height of the lid 64 and the top of the dip coating tank 61 were adjusted to the same height) · Dd: 100 mmφ · Fd: 130 mmφ

Comparative Example 3 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the dip coating apparatus 10 of FIG. 1 was used under the following conditions when forming the charge transport layer.・ Dh: + 10mm ・ Dd: 100mmφ ・ Fd: 160mmφ

Example 3 In forming the charge transport layer, the dip coating apparatus 20 of FIG. 2 set under the following conditions was used.
(A) type (axial length Hl: 150 mm,
An electrophotographic photosensitive member was produced in the same manner as in Example 1, except that the inner diameter was 130 mm.・ Dh: + 15mm ・ Dd: 110mmφ ・ Fd: 130mmφ

Example 4 In forming the charge transport layer, the dip coating apparatus 20 of FIG. 2 set under the following conditions was used.
(B) Type (axial length Hl: 150 mm,
An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the inner diameter was 130 mm and the mesh opening diameter was 50 μmφ.・ Dh: + 15mm ・ Dd: 110mmφ ・ Fd: 130mmφ

Comparative Example 4 When forming the charge transport layer, the dip coating apparatus 70 of FIG. 7 set under the following conditions was used.
(A) type (axial length Hl: 150 mm,
An inner diameter of 130 mm) was used and an electrophotographic photosensitive member was produced in the same manner as in Example 1 except for the above.・ Dh: -10mm ・ Dd: 110mmφ ・ Fd: 130mmφ

COMPARATIVE EXAMPLE 5 When forming the charge transport layer, the dip coating apparatus 70 of FIG. 7 set under the following conditions was used.
(B) Type (axial length Hl: 150 mm,
An electrophotographic photoreceptor was produced in the same manner as in Example 2 except for using an inner diameter of 130 mm and a mesh opening diameter of 50 μmφ.・ Dh: -10mm ・ Dd: 110mmφ ・ Fd: 130mmφ

[Evaluation Test] With respect to the electrophotographic photosensitive members of Examples 1 to 4 and Comparative Examples 1 to 5 , the thickness of the charge transport layer was measured by using an interference film thickness meter (MCPD-
2000, manufactured by Otsuka Electronics Co., Ltd.) to evaluate the uniformity of the coating film. Evaluation items were classified into three types: 1) upper-end film thickness sagging, 2-a) in-plane circumferential unevenness, and 2-b) in-plane axial unevenness, and evaluation was performed by the following evaluation methods and criteria. Furthermore, based on these results, comprehensive judgment was made according to the following criteria. Table 1 shows the results.

[Evaluation Method and Evaluation Criteria] With respect to the electrophotographic photosensitive members of Examples 1 to 4 and Comparative Examples 1 to 5 , when forming the coating film of the charge transport layer, the axial direction of the substrate was perpendicular to the dip coating tank 11. When immersed, the upper end is the upper end and the lower end is the lower end. FIG. 8 is a graph showing a change in the thickness of the electrophotographic photosensitive member of Example 1 in the axial direction. The horizontal axis indicates the distance from the upper end of the electrophotographic photosensitive member, and the vertical axis indicates the film thickness. The film thickness at each distance from the upper end is plotted. As can be seen from this graph, the film thickness sharply increases up to about 15 mm from the upper end, gradually stabilizes from about 15 mm, and becomes 50 m
From about m, the film becomes stable at a substantially constant film thickness. Since both ends of an electrophotographic photoreceptor to be put to practical use are not used, there is no problem that the film thickness suddenly changes to about 15 mm from the upper end. However, there is a possibility that the portion 15 mm or more from the upper end becomes a portion to be actually used as a photoreceptor, and instability of the film thickness (thickness sagging) 15 mm or more from the upper end is particularly problematic.

Therefore, in this evaluation, the electrophotographic photosensitive members of Examples 1 to 4 and Comparative Examples 1 to 5 were 50
Any number of points between 300 mm and 300 mm are measured, and the average value is defined as an average film thickness ta (μm). Meanwhile, the film thickness tx (μm) at a point 15 mm from the upper end is measured, and the value of ta−tx is calculated. The upper end film thickness was sagged. Further, evaluation was performed according to the following evaluation criteria. ：: less than 0.8 μm △: 0.8 μm or more and less than 1.1 μm ×: 1.1 μm or more

2) In-plane unevenness FIG. 9 is a perspective view of an electrophotographic photosensitive member for explaining a method for evaluating in-plane unevenness. The left side is the upper end of the electrophotographic photosensitive member, and the right side is the lower end. As shown in the figure, the film thickness was measured at four points (ABCD) at 50 mm in the axial direction from the upper end and at equal intervals in the circumferential direction, and the four points at 170 mm and 290 mm in the axial direction from the upper end were similarly measured. (A '
B'C'D 'and A "B" C "D"), and the film thickness was measured at a total of 12 points.

2-a) Unevenness in circumferential direction Four points (A'B'C ') at 170 mm in the axial direction from the upper end
The difference between the maximum value and the minimum value of each film thickness in D ') was defined as circumferential unevenness. 2-b) Unevenness in axial direction Measured values at four points (ABCD) at 50 mm in the axial direction from the upper end, four points at 170 mm (A'B'C'D '), and four points at 290 mm ( A "B" C "D") were averaged, and the difference between the maximum value and the minimum value of the obtained numerical values was defined as axial unevenness.

Further, in-plane unevenness was evaluated according to the following evaluation criteria. ○: unevenness in the circumferential direction is 1.5 μm or less and unevenness in the axial direction is 1.0 μm or less ×: unevenness in the circumferential direction is larger than 1.5 μm or unevenness in the axial direction is larger than 1.0 μm

3) Comprehensive Judgment Comprehensive judgment was made based on the following criteria based on both the evaluation results of 1) upper end film thickness sag and 2) in-plane unevenness obtained above. ：: Both the evaluation of film thickness sagging at the upper end and the evaluation of in-plane unevenness are “○”.
△: Thickness sag at the upper end is “○” ×: Thickness sag at the upper end is “△” or “X”

[0062]

[Table 1]

As can be seen from the above results, Examples 1 to 3 using the dip coating apparatus (electrophotographic production apparatus) of the present invention were used.
It can be seen that Sample No. 4 can provide a uniform coating surface with a small thickness sagging at the upper end. On the other hand , Fd
In Comparative Example 3 where / Dd exceeds 1.5, the flow pan 12
The unevenness in the surface, which is considered to be due to the influence of the solvent vapor, is slightly increased. Example 3 provided with a hood 16
And 4 to Examples 1 and 2 was not provided it
Has slightly larger in-plane unevenness (especially unevenness in the circumferential direction) which is considered to be due to the influence of external wind.

[0064]

According to the dip coating apparatus of the present invention described above, the overflow surface of the dip coating surface is higher than the flow pan wall for receiving the overflowing liquid and protrudes from the lid of the flow pan. The lowering of the solvent vapor concentration described above is achieved, and a uniform film thickness of the object to be coated can be achieved. Further, if the coating apparatus is used as an electrophotographic photoreceptor manufacturing apparatus, an electrophotographic photoreceptor having a uniform thickness of a photosensitive layer and excellent photoreceptor characteristics can be industrially advantageously produced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a dip coating apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a dip coating apparatus according to an embodiment provided with a hood of the present invention.

3A and 3B are perspective views showing specific examples of the hood in FIG. 2, wherein FIG. 3A is an example in which a communication hole is provided at a lower end portion, and FIG. 3B is an example in which the entire hood has a mesh shape.

FIG. 4 is a perspective view showing a dip coating apparatus according to an embodiment having eight dip coating tanks of the present invention.

FIG. 5 is a sectional view of the dip coating apparatus of FIG.

FIG. 6 is a schematic configuration diagram illustrating an example of a conventional dip coating apparatus.

FIG. 7 is a schematic configuration diagram showing a dip coating apparatus used in a comparative example.

FIG. 8 is a graph for explaining a method of evaluating upper-end film thickness sagging in an example.

FIG. 9 is a diagram illustrating a method for evaluating in-plane unevenness in an example.

[Explanation of symbols]

 10, 20, 40, 60, 70: dip coating apparatus 11, 61: dip coating tank 12, 62: flow pan (coating liquid receiving tray) 13, 63: return pipe 14, 64: lid 15, 65: coating liquid recovery layer 16, 16a: Hood 17, 67: Pipe 18: Opening 19: Communication hole P: Liquid feeding means F: Filter

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B05C 3/09-3/109 G03G 5/05 102

Claims (12)

(57) [Claims] 1. An object to be coated, which holds a coating solution containing a solvent.
SoakCylindricalA dip coating tank and the outer periphery of the dip coating tank
And a coating liquid in the dip coating tank.
Liquid supply means for supplying
The coating liquid is supplied from the bottom of the cloth tank, and the top of the dip coating tank is opened.
Overflows the coating liquid from the
The coating liquid is again collected by the liquid feeding means.
Circulating the coating liquid by supplying it to the dip coating tank
In the dip coating device, on the coating liquid panendPart
Has an opening larger than the outer circumference of the dip coating tankCircularlid
ToThe dip coating tank and the opening of the lid are concentric.
Sea urchinProvided,Outer diameter Dd (mm) of the dip coating tank and the lid
Has the following relationship with the opening diameter Fd (mm) of 1 <Fd / Dd ≦ 1.5 Fd-Dd ≧ 4 (mm)  The upper end of the dip coating tank is projected from the opening of the lid, and the coating is performed.
Flow solvent vapor from the liquid below the top of the coating tank
A dip coating apparatus characterized by the above-mentioned. 2. A cylindrical hood, which is open at both ends in the axial direction, has an inner diameter equal to or greater than the opening diameter of the lid, and has a communication hole provided on the outer periphery thereof for communication with the outside, 2. The arrangement as claimed in claim 1, wherein said opening is concentric with said opening.
A dip coating device according to item 1. 3. The dip coating apparatus according to claim 2 , wherein the communication hole is provided at a lower end portion of an outer periphery of the hood and / or a peripheral portion thereof. 4. The dip coating apparatus according to claim 2 , wherein the communication hole is provided on the entire outer periphery of the hood. 5. The dip coating apparatus according to claim 2 , wherein the outer periphery of the hood is a mesh having an opening diameter of 10 μm to 1 mm. 6. immersed has a plurality of coating tank, and dip coating apparatus according to any one of claims 1 to 5, characterized in that the same number of openings and dip coating tank is provided in the lid. 7. A composition containing a solvent for forming a constituent layer of an electrophotographic photosensitive member.
Dip coating to hold the coating liquid
Tank and a coating liquid receiving tray provided on the outer periphery of the dip coating tank
And a liquid feeding means for supplying a coating liquid to the dip coating tank,
Supplying the coating liquid from the bottom of the dip coating tank by liquid feeding means
Then, the coating liquid overflows from the upper opening of the dip coating tank, and overflows.
Collect the flowed coating liquid in the coating liquid tray, and apply it again.
Supplying a liquid to the dip coating tank by the liquid feeding means;
By circulating the coating liquid, it was immersed in the dip coating tank
Pull up the cylindrical substrate and configure the electrophotographic photoreceptor on its peripheral surface
In the apparatus for manufacturing an electrophotographic photoreceptor for forming a layer,
On the coating liquid panendPart is larger than the outer circumference of the dip coating tank
Has a nice openingCircularLidOf the dip coating tank and the lid
So that the opening is concentricProvided,Outside of the dip coating tank
The diameter Dd (mm) and the opening diameter Fd (mm) of the lid are as follows.
Has the following relationship, 1 <Fd / Dd ≦ 1.5 Fd-Dd ≧ 4 (mm)  The upper end of the dip coating tank protrudes from the opening of the lid,
The vapor of the solvent from the cloth liquid flows below the upper end of the coating tank.
An apparatus for manufacturing an electrophotographic photoreceptor. 8. A cylindrical hood having an opening at both ends in the axial direction, having an inner diameter equal to or larger than the opening diameter of the lid, and having a communication hole provided on the outer periphery thereof for communicating with the outside, the upper part of the opening of the lid. 8. An arrangement according to claim 7, wherein said opening is concentric with said opening.
3. The apparatus for manufacturing an electrophotographic photoreceptor according to claim 1. 9. communication hole, the hood of the outer circumference of the lower end portion and / or the production apparatus of the electrophotographic photosensitive member according to claim 8, characterized in that provided in the peripheral portion. 10. A communication hole, the manufacturing apparatus of the electrophotographic photosensitive member according to claim 8, characterized in that provided on the entire surface of the outer periphery of the hood. 11. the outer periphery of the hood, the manufacturing apparatus of the electrophotographic photosensitive member according to claim 8, characterized in that a mesh opening size of 10 .mu.m to 1 mm. 12. The manufacturing apparatus of an electrophotographic photosensitive member according to any one of claims 7 to 11, characterized in that a plurality of dip coating tank.