JPH06161121A - Holder for applying photosensitive layer to conductive base for electrophotographic photosensitive body - Google Patents

Abstract

PURPOSE:To simplify a clamp mechanism by constituting it of a spring type clamp part with an operating shaft, and also to eliminate the irregularity of application of a photosensitive layer and the generation of brushing by using this holder to control radiational cooling when an application liquid solvent is evaporated. CONSTITUTION:An operating shaft 3 is twisted in the direction as shown with an arrow so that the outer diameter of a spring type clamp part 2, and this holder is inserted into the inner part of a seamless belt-like base and then the operating shaft is reversely twisted before its insertion. Thereby, the clamp part 2 reaches the inner diameter of the seamless belt, and further when the operating shaft is continuously twisted, tension is applied to the seamless belt- like base to hold the seamless belt-like base. An electric charge generating layer and an electric charge transferring layer are provided on the set seamless belt-like base. When an electrophotographic photosensitive element is used as mentioned above, such application defects as irregularity of application, brushing and the like can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holder for coating a photosensitive layer on a conductive substrate for an electrophotographic photoreceptor. In particular, the present invention relates to a holder for coating a photosensitive layer on a conductive substrate for an electrophotographic photoreceptor having a seamless belt shape or a cylindrical shape.

[0002]

2. Description of the Related Art Electrophotographic photoreceptors currently in practical use can be roughly classified into those using an inorganic material and those using an organic material. As a typical photoreceptor of inorganic material,
A selenium-based material such as amorphous selenium (a-Se) or amorphous selenium arsenic (a-As ₂ Se ₃ ), dye-sensitized zinc oxide (ZnO), or cadmium sulfide (CdS) is dispersed in a binder resin. Examples thereof include those using amorphous silicon (a-Si), and the like. In addition, as a typical photoreceptor of an organic material, 2,
Examples thereof include those using a charge transfer complex of 4,7-trinitro-9-fluorenone (TNF) and poly-N-vinylcarbazole (PVK).

These inorganic photoconductors have many advantages and at the same time have drawbacks. For example, a photoconductor using selenium and CdS has problems in heat resistance and storage safety, and has a limitation that it cannot be easily discarded and must be recovered because it has toxicity. Zn
O-resin-dispersed photoconductors are now almost obsolete because of low sensitivity and lack of durability. In addition, a-Si
Although the photoreceptor has excellent advantages such as high sensitivity and high printing durability, it leaves behind problems such as high manufacturing cost due to the complexity of its manufacturing process and image defects due to defects during film formation. There is.

On the other hand, the organic photoreceptor has various organic materials scattered therein and can be arranged in a variety of ways by synthesis. Therefore, problems such as storage stability and toxicity can be avoided by appropriately selecting them. Further, since it can be manufactured at low cost, it has been extensively studied in a wide range, but the organic photoreceptor also has a problem of low sensitivity, and its improvement is being promoted. PVK-T mentioned earlier
The NF charge transfer complex was one of the improvements, but it did not reach sufficient sensitivity.

Therefore, various other sensitizing methods have been proposed, for example, a layer containing a substance (hereinafter referred to as "charge generating substance") that generates a charge carrier when irradiated with light (hereinafter referred to as "charge generating layer"). And a layer mainly composed of a substance (hereinafter, referred to as "charge transport substance") that receives and transports charge carriers generated in the charge generation layer (hereinafter referred to as "charge transport layer"). Since the photoconductor of (1) (hereinafter referred to as "function-separated photoconductor") exhibits excellent sensitization properties, it has accounted for most of the organic photoconductor structures currently in practical use. Further, it is expected as the mainstream of photoconductors in the future due to the improvement of durability in recent years.

As the conductive substrate in the present invention, one having conductivity in itself, for example, aluminum, aluminum alloy, copper, zinc, stainless steel, nickel, titanium and the like can be used. In addition, aluminum, aluminum alloy, A plastic or paper in which indium oxide, tin oxide, or the like is deposited or applied, a plastic or paper containing conductive particles, a plastic having a conductive polymer, or the like can be used. A charge generation layer is formed on the conductive substrate. As the charge generation material used for the charge generation layer, a bisazo compound such as chlorodian blue, a polycyclic quinone compound such as dibromoanthansulone,
A perylene-based compound, a quinacridone-based compound, a phthalocyanine-based compound, a mazulenium salt-based compound, or the like can be used. As a method for forming the charge generation layer, there are a method of directly forming a compound by vacuum vapor deposition and a method of dispersing in a binder resin solution and coating to form a film, but the latter method is generally preferable.

As a coating method, a dip coater, a blade coater, an applicator, a rod coater, a knife coater, a spray coater or the like can be used. The thickness of the charge generation layer is 0.05 to 5 μm.
m, preferably 0.1 to 1 μm. In the case of production by coating, as a method of mixing and dispersing the charge generating material in the binder resin solution, there are a ball mill, a sand mill, an attritor, a vibration mill, an ultrasonic disperser and the like. As the coating method, there are melamine resin, epoxy resin, silicone resin, polyurethane resin, acrylic resin, vinyl chloride-vinyl acetate copolymer resin, polycarbonate resin, phenoxy resin, and the like, and the solvent for dissolving these resins is acetone. , Ketones such as methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, ethers such as tetrahydrofuran and dioxane, aromatic hydrocarbons such as benzene, toluene and xylene, N, N
-Aprotic polar solvents such as dimethylformamide and dimethylsulfoxide can be used.

Examples of the charge transport material of the charge transport layer provided on the charge generation layer include hydrazone compounds, pyrazoline compounds, triphenylamine compounds, triphenylmethane compounds, stilbene compounds, oxadiazole compounds. Etc. can be used, and the charge transporting coating liquid is prepared by dissolving the charge transporting substance in the binder resin solution. This charge transport layer can be formed by the coating method described above. The thickness of the charge transport layer is 5 to 50 μm.
m, preferably 10 to 40 μm.

A layer called an undercoat layer may be provided between the conductive substrate and the photosensitive layer for the purpose of improving the characteristics.

The electrophotographic photosensitive member manufactured as described above may have a drum shape, a sheet shape, or a seamless belt shape, and most of them are drum-shaped photosensitive members. However, in recent years, electrophotographic copying machines have been required to be smaller, lighter and faster, and drum-shaped photoconductors have limitations. Therefore, seamless belt-shaped photoconductors will be used as an alternative to drum-shaped photoconductors in the future. The body is highly expected.

[0011]

As described above, by making the organic photosensitive member a seamless belt type photosensitive member, it is possible to reduce the size, weight and speed of the electrophotographic copying machine. Most of the commercially available seamless belt-shaped photoconductors have a seam formed by joining both edges of a sheet-shaped photoconductor, and the seam portion cannot be used for image formation. Therefore, such a photoconductor is used. A copying machine or the like requires a device for detecting a seam, which makes it difficult to reduce the size, weight and speed of the electrophotographic copying machine. Further, in the case of a photoreceptor having a joint, there is a problem that the joint portion is damaged by a cleaning blade or the like, and peeling occurs near the joint portion. JP-A-60-249152, JP-A-61-107281, JP-A-1-288860
Japanese Patent Application Laid-Open No. 2-195372 and the like disclose methods for improving such problems. However, the seamless belt-shaped photoreceptor produced by these methods has a small step at the joint. Although the above problems are considerably improved, it is impossible to completely eliminate the seams.

Further, various methods for forming a photosensitive layer on a seamless seamless belt-like substrate have been proposed in JP-A-61-39048, JP-A-63-61254 and JP-A-3-269437. However, because the coating device is complicated or the seamless belt-shaped substrate itself is a thin film, a defective coating film caused by evaporation of an organic solvent during coating of the photosensitive layer, for example, coating unevenness or brushing, can be used to form a good photosensitive layer. There is a problem that can not be obtained.

FIG. 5 shows a clamp-type substrate holder which is an example of a substrate holder conventionally used when a photosensitive layer is applied and formed on a conductive substrate.

The clamp-type base body holder 10 has a structure in which a base body holding portion 11 that can slide left and right in the figure is connected to another base body holding portion 12 via a spring.

A method of using the clamp type substrate holder 10 having such a structure will be described with reference to FIG. The slidable base holding part 11 is slid to the left, and the clamp type holding tool 10
Is inserted into the conductive substrate 1 (eg, seamless belt-shaped substrate). Then, the slidable substrate holding unit 11 is slid to the right to hold the substrate.

In the case of the clamp type substrate holder 10 having such a structure, a difference in heat capacity occurs on the substrate surface between the substrate holding portions 11 and 12 and the space portion between them, which causes the coating liquid. The difference in evaporation of the solvent causes the uneven coating. In this space, moisture is taken into the coating film due to the heat of vaporization, which causes brushing failure.

The present invention has been made in view of the above-mentioned problems when the conventional photosensitive layer is coated.

[0018]

In order to achieve the above object, in the present invention, when a photosensitive layer is formed by coating on a conductive substrate, particularly a seamless belt-shaped or cylindrical conductive substrate, The seamless belt-shaped or cylindrical conductive substrate was held by a substrate holder constituted by a spring type clamp portion with an operating shaft.

The material, shape, etc. of the spring type clamp portion used in the holder of the present invention are not particularly limited.
The heat capacity is increased so that uneven coating and brushing due to evaporation of the organic solvent in the coating liquid can be suppressed.

[0020]

The operation shaft is twisted so that the outer diameter of the spring type clamp portion becomes thin, and the base body holder is inserted into the seamless belt or cylindrical base body. Next, by twisting the operating shaft in the direction opposite to that before insertion, the spring of the spring type clamp portion is brought into contact with the inside of the base body,
Holds a seamless belt or cylindrical substrate. A photosensitive layer is formed on the substrate thus held by a conventional method.

[0021]

The preferred embodiments of the present invention will be described below with reference to the accompanying drawings, but the invention is not limited to the following embodiments unless the gist thereof is exceeded.

Example 1 FIG. 1 is a schematic view showing a state in which a substrate is held by a holder 10 for coating a photosensitive layer of a conductive substrate for an electrophotographic photoreceptor of the present invention, which is composed of a spring type clamp portion with an operating shaft. FIG. 1 is a cross-sectional view, in which 1 is a seamless belt-like substrate having a thickness of 100 μm formed by depositing aluminum on the surface of a polyethylene terephthalate film, 2 is a spring type clamp part, 3 is an operating shaft, 4 is a holder rotation preventing guide. Reference numeral 5 is a holder lifting platform.

Next, a procedure for holding the seamless belt-shaped substrate 1 by the above-mentioned holding device for coating the photosensitive layer 10 of the conductive substrate is shown in FIGS.

As shown in FIG. 2 (a), the operating shaft 3 is twisted in the direction of the arrow so that the outer diameter of the spring type clamp portion 2 becomes thin, and inside the seamless belt-shaped substrate 1 shown in FIG. 2 (b). As shown in FIG. 3, by inserting the holder and twisting the operating shaft in the direction of the arrow opposite to the direction before insertion, the spring type clamp portion 2 reaches the inner diameter of the seat belt and continues to twist further. Then, tension is applied to the seamless belt-shaped substrate, and the seamless belt-shaped substrate is held as shown in FIG.

The seamless belt-shaped substrate set in this way is, for example, represented by the following structural formula (I):

[0026]

[Chemical 1]

Bisazo pigment (chlorguan blue)
Using a paint shaker, a mixture of 1.5 parts by weight of butyral resin (Union Carbide Co., Ltd .: XYGS) and 1.5 parts by weight of methyl isobutyl ketone was used.
The charge generation layer was provided on the seamless belt-shaped substrate by dispersing the solution for a period of time, immersing it in the prepared coating solution for the charge generation layer, and pulling it out. Furthermore, the following structural formula (II)

[0028]

[Chemical 2]

Hydrazone compounds (4, -diethylaminobenzaldehyde-N, N-diphenylhydrazone)
1 part by weight and polycarbonate resin (manufactured by Mitsubishi Gas Chemical Company:
1 part by weight of Iupilon) and 8 parts by weight of dichloromethane were stirred and dissolved, and the prepared charge transport layer coating solution was applied by dip coating in the same manner as the charge generation layer, followed by hot air drying at a drying temperature of 80 ° C. for 1 hour. Then, a charge transport layer having a dry film thickness of 20 μm was provided to prepare a function-separated electrophotographic photoreceptor.

The electrophotographic photosensitive member used in this manner has no coating defects such as coating unevenness and brushing, and has good image characteristics in an actual copying test by an actual device (Sharp Co., Ltd .: SF-8100). Was obtained.

Example 2 The function-separated electrophotographic photoreceptor was subjected to dip coating in the same manner as in Example 1 except that the seamless belt-shaped substrate of Example 1 was replaced with an aluminum cylindrical substrate having a diameter of 80 mm and a length of 340 mm. Was produced. In this case as well, the appearance inspection and actual copying test of the photoconductor were performed in the same manner as in Example 1, but good image characteristics were obtained without coating film defects.

Example 3 Same as Example 1 except that the seamless belt-shaped substrate having aluminum deposited on the surface of the polyethylene terephthalate film used in Example 1 was replaced with a seamless belt-shaped substrate made of aluminum having a thickness of 100 μm. Dip coating was performed to produce a function-separated electrophotographic photoreceptor. In this case as well, the appearance inspection and actual copying test of the photoconductor were carried out in the same manner as in Example 1, but good image characteristics were obtained without coating film defects.

Comparative Example 1 Same as Example 1 except that the photosensitive layer coating substrate holder 10 used in Example 1 was replaced by a clamp type photosensitive layer coating substrate holder 10 as shown in FIG. Thus, dip coating was performed to prepare a function-separated electrophotographic photoreceptor.

In this case as well, when the appearance inspection and the actual copying test of the photosensitive member were conducted in the same manner as in Example 1, the two clamp parts 1
The space in the center of 1 and 12 causes a difference in heat capacity on the surface of the seamless belt, which causes uneven coating and brushing of the photosensitive layer, and good image characteristics cannot be obtained.

[0035]

Since the substrate holder for coating the photosensitive layer of the present invention has the above structure, the clamp mechanism can be simplified as compared with the conventional one. Further, by using this holder, the spring comes into contact with the entire surface of the inside of the substrate, so that the radiative cooling at the time of evaporation of the coating liquid solvent can be controlled and the coating property of the photosensitive layer without uneven coating and brushing An excellent electrophotographic photoreceptor can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a state in which a substrate is held by a substrate holder for coating a photosensitive layer of the present invention.

FIG. 2 is a schematic view showing a state immediately before the substrate holder for coating a photosensitive layer of the present invention is inserted into a substrate.

FIG. 3 is a schematic view showing a state where the substrate holder for coating a photosensitive layer of the present invention is inserted into a substrate.

FIG. 4 is a schematic view showing a state where a substrate is held by the substrate holder for coating a photosensitive layer of the present invention.

FIG. 5 is a schematic view showing a conventional substrate holder for coating a photosensitive layer.

FIG. 6 is a schematic view showing a state in which a conventional substrate holder for coating a photosensitive layer is inserted into a substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductive base material 2 Spring type clamp part 3 Operation shaft 4 Holding tool rotation prevention guide 5 Holding tool lifting / lowering platform 10 Photosensitive layer application base material holding tool 11 Slidable base material holding part 12 Base material holding part

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Mitsuhiro Shinobu 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Co., Ltd. Inside the Sharp Corporation (72) Inventor Kazuyuki Arai 22-22 Nagaike-cho, Abeno-ku, Osaka City, Osaka Prefecture Inside the Sharp Corporation

Claims (2)

[Claims] 1. A holder for coating a photosensitive layer on a conductive substrate for an electrophotographic photosensitive member, which is composed of a spring type clamp portion with an operating shaft. 2. The holder for coating a photosensitive layer of a conductive substrate for an electrophotographic photoreceptor according to claim 1, wherein the conductive substrate has a seamless belt shape or a cylindrical shape.