JP2000010305A - Manufacturing device of electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing device of an electrophotographic photoreceptor capable of forming a uniform applying film by preventing the occurrence of nonuniformity of steps by a pulsating flow in forming a photosensitive layer on a support base body by a soaking applying method. SOLUTION: In a manufacturing device of an electrophotographic photoreceptor by a soaking applying method which is provided with an applying tank 1 for applying an applying liquid to a substrate, an applying liquid storage tank 2 for recovering the applying liquid overflowing from the upper part of the applying tank 1 and a circulating passage for supplying the applying liquid to the lower part of the applying tank 1 by a circulating pump from the applying liquid storage tank 2, a check valve 4 is arranged in piping of the circulating passage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing an electrophotographic photosensitive member by a continuous circulation type dip coating method, and more particularly, to an electrophotographic photosensitive member used in at least a printer, a copying machine, a facsimile, and the like. The present invention relates to an apparatus for manufacturing by applying a photoconductive coating solution to a supporting substrate by a dip coating method.

[0002]

2. Description of the Related Art An electrophotographic apparatus using a photoconductor for electrophotography has been conventionally applied to copying machines and the like, and has been widely used.
In recent years, it has been applied to laser beam printers, facsimile machines, and the like, and its application range is rapidly expanding due to features such as high image quality, high speed, and low noise. An electrophotographic photoconductor applied to these electrophotographic apparatuses is manufactured by forming a photosensitive layer of a photoconductive material on a supporting substrate. In recent years, organic compounds have been increasing in the photoconductive material applied to such a photosensitive layer from the viewpoint of material diversity and toxicity.

[0003] As a method for forming a photosensitive layer using these photoconductive materials, a coating method is widely applied. Above all, the dip coating method is widely applied as a method excellent in mass productivity. In the dip coating method, a photoconductive layer is formed by immersing a supporting substrate of an electrophotographic photoreceptor in a photoconductive layer coating solution and then pulling it up at an appropriate speed. 2. Description of the Related Art Conventionally, an apparatus for manufacturing an electrophotographic photosensitive member by dip coating generally includes a circulation system for circulating a coating solution and an elevating device for immersing a substrate of the photosensitive member in an application tank. Such a circulation system generally includes a coating tank for applying a coating liquid to a supporting substrate, a coating liquid storage tank for collecting the coating liquid overflowing from the upper part of the coating tank, and a coating pump for applying a coating liquid from the coating liquid storage tank. A circulation path for circulating the liquid. The coating liquid is supplied to the coating tank from the lower part by a pump in a circulation path, and the coating liquid that exceeds the capacity of the coating tank overflows from the upper part of the coating tank, and the overflowing coating liquid is collected in the coating liquid tank. It has a mechanism. This allows
The liquid level in the coating tank is kept constant, and the photosensitive layer is formed on the supporting substrate by immersing the substrate therein and pulling it up at a constant speed. Further, if necessary, a drying treatment is performed after the application.

However, when a circulation pump or the like is provided in the circulation path as described above, mechanical unevenness (commonly referred to as step unevenness) due to a pulsating flow of the circulation pump or the like may occur, which causes a problem in uniformity of the coating film. Occurred. As measures against this, it has been proposed to provide an air chamber (air chamber) for smoothing a pulsating flow between the pump and the coating tank, or to increase the pressure in the air chamber with nitrogen, air, or the like. (JP-A-1-148360).

[0005]

The means conventionally proposed as a measure against the problem of the uniformity of the coating film by the dip coating method is difficult to completely suppress the pulsating flow, and an apparatus such as an air chamber is provided. Space is needed.

Accordingly, an object of the present invention is to provide an electrophotographic photoreceptor capable of preventing a step unevenness due to a pulsating flow and forming a uniform coating film when a photosensitive layer is formed on a supporting substrate by a dip coating method. To provide a manufacturing apparatus.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventor has found that the above object can be achieved by providing a check valve in the piping of the coating liquid circulation path. The present invention has been completed.

That is, the apparatus for producing an electrophotographic photoreceptor of the present invention comprises a coating tank for coating a substrate with a coating liquid, a coating liquid storage tank for collecting the coating liquid overflowing from the upper part of the coating tank,
A circulating path for supplying the coating liquid from the coating liquid storage tank to the lower portion of the coating tank by a circulating pump. A valve is provided.

[0009] When the supporting substrate is pulled up by the dip coating method, a coating liquid thin film of a photoconductive material of a μm level is first formed, and this thin film is disturbed in the flow of the coating liquid in the coating tank, particularly the overflow surface. Is strongly influenced by For example, when ripples are formed on the overflow surface, they interfere with the substrate at the time of lifting application, and as a result, when the cylindrical substrate exits the overflow surface,
It is considered that coating unevenness (density unevenness) occurs in the circumferential direction, thereby impairing the uniformity of the coated film. In the present invention, the above-described coating unevenness is completely suppressed by simply introducing a check valve to the circulation path piping to suppress the backflow of the coating liquid to the circulation pump side due to the dip coating, and to achieve uniform coating. This makes it possible to obtain a membrane, and does not require any additional equipment, such as an air chamber, which has been proposed so far, or a special control method therefor.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the substrate 5 of the electrophotographic photosensitive member is immersed in a coating solution in the coating tank 1 while being held by a holder of a lifting member. The base 5 is made of metal such as aluminum, nickel, chromium, and stainless steel,
Examples of the material include plastics provided with a thin film such as aluminum, titanium, nickel, chromium, stainless steel, tin oxide, indium oxide, and ITO, and paper or plastic coated or immersed with a conductivity-imparting agent.

The coating liquid overflowing from the coating tank 1 is collected in a coating liquid storage tank 2. The coating liquid is circulated from the coating liquid storage tank 2 to the coating tank 1 via the circulation path by the circulation pump 3. Examples of the circulation pump 3 include a rotary pump and a plunger pump, and are not limited to a specific pump. In the present invention, the check valve 4 is provided in the middle of the piping of the circulation path. Although the position of the check valve 4 is provided downstream of the circulation pump 3 in the illustrated example, it may be provided upstream. Further, a filter (not shown) can be introduced into the piping of the circulation path as required.

The check valve that can be used in the present invention does not need to be a special one, and may be of a type conventionally used for preventing backflow. The principle of such a check valve will be described with reference to FIG. In the figure, A is a liquid flow by pressure feeding from the circulation pump 3 to the coating tank 1. Meanwhile B
Is a liquid flow due to the backflow from the coating tank 1. Basically, as shown in (a), the liquid flow A from the circulating pump 3 has priority. In this case, the check valve 4 is opened and the coating liquid is applied to the coating tank
Sent to On the other hand, when the backflow increases as shown in (b) and the liquid flow of B becomes equal to or larger than A, the check valve 4 is closed.

In the apparatus of the present invention, as the elevating device for elevating the substrate, a conventionally known device can be used, and the structure itself is not particularly limited.

The coating liquid to which the apparatus of the present invention can be preferably applied is, for example, a coating liquid containing a charge generating pigment, for example, a pigment such as an azo pigment, a phthalocyanine pigment, a perinone pigment, a perylene pigment, or an anthraquinone pigment. No.

[0015]

EXAMPLES Specific examples of the present invention will be described below, but the present invention is not limited to these examples. EXAMPLE An electrophotographic photosensitive member was manufactured using a device in which a check valve was introduced between a circulation pump 3 and a coating tank 1 in a circulation path as shown in FIG.

The circulation amount at the time of application and lifting of the supporting substrate is set to 10
Liter / min, and lifting speed 2mm / s, 4mm
/ S, 6 mm / s, 8 mm / s, and 10 mm / s, the charge generating layer was applied under different conditions to produce a photoconductor for electrophotography, and the uniformity of the applied film was visually evaluated.

COMPARATIVE EXAMPLE An electrophotographic photoreceptor was manufactured under the same conditions using the same apparatus as in the example except that the check valve was removed, and the coating film was made uniform as in the example. The sex was evaluated. The results obtained are shown in Table 1 below.

[0018]

[Table 1]

As is clear from Table 1, all of the examples have good coating film uniformity, but the comparative examples show that the coating film uniformity is not stabilized by changing the pulling speed.

[0020]

According to the present invention, a check valve is simply introduced into the piping of the circulation path without requiring an air chamber or the like, and the backflow of the coating liquid from the coating tank to the circulation pump during coating is suppressed. Only by doing, a photoreceptor for electrophotography having excellent uniformity of the coating film can be manufactured.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of an apparatus for manufacturing an electrophotographic photoreceptor of the present invention.

FIG. 2 is an explanatory view of the principle of a check valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coating tank 2 Coating liquid storage tank 3 Circulation pump 4 Check valve 5 Support base 6 Stopper 7 Piping

Claims (1)

[Claims] 1. A coating tank for applying a coating liquid to a substrate, a coating liquid storage tank for collecting a coating liquid overflowing from an upper portion of the coating tank, and a coating liquid from the coating liquid storage tank which is circulated by a circulation pump. An apparatus for producing an electrophotographic photosensitive member by a dip coating method, comprising: a circulation path for supplying a coating liquid to a lower portion of a coating tank, wherein a check valve is provided in a pipe of the circulation path. Body manufacturing equipment.