JP2622757B2 - Electrophotographic photoreceptor and method of manufacturing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrophotographic photoreceptor and a method for producing the same.
More specifically, the present invention relates to an electrophotographic photosensitive member having a function-separated type photosensitive layer and a method for manufacturing the same.

BACKGROUND ART In recent years, a charge generation layer that generates charge carriers by light irradiation, and charge carriers generated in the charge generation layer can be efficiently injected,
In an electrophotographic photoreceptor having a so-called function-separated type photosensitive layer separated from a charge transport layer that can move efficiently, an amorphous silicon is used as a charge generation layer and a plasma CVD method is used as a charge transport layer. An electrophotographic photoreceptor using the formed amorphous material has attracted attention. This can fundamentally improve the chargeability and productivity of conventional amorphous silicon-based electrophotographic photoreceptors without impairing the excellent characteristics of amorphous silicon such as photosensitivity, high hardness and thermal stability. It is possible to obtain a long-life electrophotographic photoreceptor that has the possibility of having an electrically stable repetition property and a long life. Has been proposed. In such a function-separated type amorphous silicon-based electron photoreceptor, the charge transport layer is formed by a plasma CVD method, for example, from silicon oxide or amorphous carbon disclosed in U.S. Patent No. 4,634,648. Can be used.

Problems to be Solved by the Invention In an amorphous silicon-based electrophotographic photoreceptor, a charge transport layer and a charge generation layer are separated from each other, amorphous silicon is used as the charge generation layer, and amorphous is used as the charge transport layer. By using a substance having a smaller dielectric constant and a higher resistance than that of porous silicon, the chargeability can be improved and the dark decay can be reduced. However, the film formed by the plasma CVD method has the same film formation rate as that of the amorphous film and has a complicated layer structure, so that the probability of occurrence of film defects increases, and There was a problem that productivity was low and the cost was extremely high.

The present invention has been made in view of the above-described problems in the related art.

Accordingly, an object of the present invention is to provide an electrophotographic photoreceptor having a novel charge transport layer.

That is, an object of the present invention is to provide a highly durable electrophotographic photoreceptor having a charge transporting layer having good adhesion, high mechanical strength and hardness, and few defects.

Another object of the present invention is to provide an electrophotographic photoreceptor having high sensitivity, rich color, high chargeability, small dark decay, and low residual potential after exposure.

Another object of the present invention is to provide an electrophotographic photoreceptor whose charging characteristics are not affected by changes in the atmosphere of the external environment.

Still another object of the present invention is to provide an electrophotographic photosensitive member having excellent image quality even when used repeatedly.

Still another object of the present invention is to provide a method for producing the above electrophotographic photoreceptor.

Means and Action for Solving the Problems The present inventors have previously found that aluminum oxide has a function as a charge transporting layer. When an aluminum oxide film is formed, and a specific amount of metal is precipitated by electrolysis in the pores, more excellent physical properties, electrophotographic properties, and adhesion to the charge generation layer are obtained. And found that the present invention was completed.

The electrophotographic photoreceptor of the present invention comprises at least a support, a charge transport layer and a charge generation layer, and the charge transport layer is formed by anodizing a support having at least a surface made of aluminum or an aluminum alloy. A porous anodized aluminum film, wherein a metal has a height from the bottom of the hole in the pores of the porous anodized aluminum film.
It is characterized by being deposited up to 1/100 to 1/2 position.

The electrophotographic photoreceptor of the present invention, a support having at least a surface made of aluminum or an aluminum alloy, sulfuric acid, phosphoric acid, an inorganic polybasic acid selected from chromic acid and the like,
Or dipped in an acidic aqueous solution of 1 to 30% by weight of an organic polybasic acid selected from oxalic acid, malonic acid, tartaric acid, and the like;
A direct current of 0 Adm- ² was passed to form a porous anodized aluminum film on the support by anodic oxidation.
Performing electrolysis in a solution containing one or more metal salts selected from Fe, Ni, Co, Sn, Cu, and Zn and inorganic or organic ions acting as a complex for the metal, A metal is deposited in the pores of the porous anodized aluminum film from the bottom of the hole to a position of 1/100 to 1/2 of the height of the hole, and then a charge formed by the formed metal-filled porous anodized aluminum film is formed. It can be manufactured by forming a charge generation layer on a transport layer.

 Hereinafter, the present invention will be described in detail.

FIG. 1 is a schematic sectional view of an electrophotographic photoreceptor of the present invention, for example, a pipe-shaped support 1 having a diameter of 30 to 200 mm.
A porous anodized aluminum film 2 is formed thereon, and a charge generation layer 3 is formed thereon. The porous anodized aluminum oxide film 2 has a structure in which a metal 4 is deposited to a predetermined height in a hole.

In the present invention, as the support, any of aluminum and its alloys (hereinafter, these are simply referred to as aluminum), and any of a conductive support and an insulating support other than aluminum can be used. When a support other than aluminum is used, it is necessary that an aluminum film having a thickness of at least 5 μm or more is formed on at least a surface in contact with another layer. This aluminum film can be formed by an evaporation method, a sputtering method, or an ion plating method.
Examples of the conductive support other than aluminum include metals such as stainless steel, nickel, and chromium and alloys thereof, and examples of the insulating support include polymer films such as polyester, polyethylene, polycarbonate, polystyrene, polyamide, and polyimide. Examples include sheet, glass, and ceramic.

In the present invention, as an aluminum material for obtaining an anodized aluminum oxide film having good characteristics, in addition to a pure Al-based material, an Al-Mg-based, Al-Mg-Si-based, Al-Mg-Mn-based,
Al-Mn, Al-Cu-Mg, Al-Cu-Ni, Al-Cu, Al
-Si, Al-Cu-Zn, Al-Cu-Si, Al-Cu-Mg-Zn
And aluminum alloy materials such as Al-Mg-Zn.

The porous anodized aluminum oxide film formed on the aluminum surface of the support serves as a charge transport layer and is manufactured as follows.

The anodic oxidation treatment for forming a porous anodized aluminum film on the support will be described more specifically. First, the surface is mirror-finished, and the support having an aluminum surface processed into a desired shape is obtained. Degreasing is performed to completely remove oil and the like adhering during machining. For degreasing, a commercially available degreasing agent for aluminum, acid alkali, organic solvent and the like may be used.

Subsequently, a porous anodized aluminum oxide film is formed on the support. An electrolytic solution (anodizing solution) made of stainless steel or hard glass is filled with an electrolyte solution (anodic oxidizing solution) to a predetermined liquid level. As the electrolyte solution, an acidic aqueous solution of 1 to 30% by weight of an inorganic polybasic acid selected from sulfuric acid, phosphoric acid, chromic acid, or the like, or an organic polybasic acid selected from oxalic acid, malonic acid, tartaric acid, or the like is used. . Examples of pure water used as a solvent include distilled water and ion-exchanged water. Particularly, impurities such as chlorine are sufficiently removed to prevent corrosion of an anodized aluminum film and generation of pinholes. Is necessary for

Next, the support having the aluminum surface as an anode and a stainless steel plate or an aluminum plate as a cathode are immersed in the electrolyte solution at a certain distance between the electrodes. In this case, the distance between the electrodes is 0.1 cm to 100 cm
It is set appropriately between. A DC power supply is prepared, its positive (plus) terminal is connected to the aluminum surface, and its negative (minus) terminal is connected to the cathode plate, and current is passed between the anode and cathode electrodes in the electrolyte solution. The electrolysis is performed by a constant current method or a constant voltage method according to a conventional method, and the applied direct current may be composed of only a direct current component or may be a superimposed alternating current component. The current density during the anodic oxidation is set in the range of 0.1 to 10 A · dm ^-2 . In consideration of the film growth rate and cooling efficiency, it is preferable to set the range of 0.5 to 3.0 A · dm ⁻² . The anodic oxidation voltage is usually 3 to 150 V, preferably 7 to 100 V. The temperature of the electrolyte solution is set to -5 to 100C.

In the present invention, from the viewpoints of production efficiency, production speed, film properties, etc., one of the most preferable examples is 10 to 20% by weight.
It is to be carried out in a range of 15 to 25 ° C using an aqueous sulfuric acid solution.

This energization forms a porous anodized aluminum oxide film on the aluminum surface of the support serving as the anode.

The thickness of the porous anodized aluminum oxide film can be controlled by changing the electrolysis time.
5050 μm, preferably 5-30 μm. In this case, if it is less than 3 μm, the charging potential becomes low,
If it exceeds 50 μm, the production cost becomes high, and a film crack occurs, which is not preferable.

The anodized aluminum oxide film thus formed is washed with water, and then a metal is precipitated by electrolysis in the pores of the formed porous anodized aluminum film.
The metal contributes to the charge transport property as a conductive substance by the deposition of the metal, and improves the charge transport ability of the charge transport layer. The metal to be filled is desirably one or more selected from Fe, Ni, Co, Sn, Cu and Zn.

In order for these metals to be electrolytically deposited, one or more metal salts selected from Fe, Ni, Co, Sn, Cu and Zn as an electrolyte and a complexing agent for the metal. Electrolysis is performed by using a solution containing an acting inorganic or organic ion and using an alternating current or a similar current having a large amount of a cathode current component as viewed from a sample.

As the metal salt used in the electrolytic solution, for example, ammonium sulfate, nickel sulfate, cobalt sulfate, stannous sulfate, copper sulfate, zinc sulfate, etc. Any material that dissociates ions may be used.

Examples of the substance that becomes an inorganic or organic ion that acts as a complexing agent on the metal include, for example, boric acid, sulfamic acid, ammonium sulfate, and the like, and substances that become an organic ion such as citric acid and tartaric acid. , Phthalic acid, malonic acid, malic acid and the like can be used.

The electrolysis is performed by adjusting the amount of electricity so that the metal is deposited in a range from the bottom of the hole of the porous anodized aluminum oxide film to a position of 1/100 to 1/2 of the height of the hole. The adjustment of the amount of electricity can be performed, for example, by adjusting the electrolysis time. In this case, if it is less than 1/100, the charge transport property is poor,
On the other hand, when the ratio exceeds 帯 電, the chargeability is lowered, which is not preferable.

The porous anodized aluminum film formed as described above is washed with water, and then washed with ion-exchanged water or pure water.
For example, it is dried promptly in dry air at 80 ° C. or higher.

Next, on this porous anodized aluminum oxide film, a charge generation layer is formed as a direct contact, and an inorganic substance such as amorphous silicon, selenium, hydrogen selenide, and selenium-tellurium is used as the charge generation layer. One formed by a method such as CVD, vapor deposition, or sputtering can be used. Further, a thin film obtained by a method such as immersion coating or the like by depositing a dye such as phthalocyanine, copper phthalocyanine, Al phthalocyanine, a square phosphoric acid derivative, or a bisazo dye, or by dispersing in a binder resin can be used. Above all, it is preferable to use amorphous silicon to which amorphous silicon or germanium is added, because it exhibits excellent mechanical and electrical characteristics.

Hereinafter, a case where the charge generation layer is formed using amorphous silicon will be described as an example.

The charge generation layer containing amorphous silicon as a main component can be formed by a known method. For example, it can be formed by a glow discharge decomposition method, a sputtering method, an ion plating method, a vacuum evaporation method, or the like. These film forming methods are appropriately selected depending on the purpose,
A method of glow discharge decomposition of silane or a silane-based gas by a CVD method is preferable. According to this method, a film having a relatively high dark resistance containing an appropriate amount of hydrogen in the film and having high photosensitivity is formed, Suitable characteristics can be obtained for the charge generation layer.

 Hereinafter, the plasma CVD method will be described as an example.

Examples of raw materials for forming the amorphous silicon photosensitive layer containing silicon as a main component include silanes such as silane and disilane. In forming the charge generation layer, a carrier gas such as hydrogen, helium, argon, or neon can be used as necessary. Further, a dopant gas such as diborane (B ₂ H ₆ ) gas or phosphine (PH ₃ ) gas may be mixed into these source gases, and an impurity element such as boron or phosphorus may be added to the film. Further, a halogen atom, a carbon atom, an oxygen atom, a nitrogen atom and the like may be contained in the photosensitive layer for the purpose of increasing the light sensitivity and the like. Furthermore, for the purpose of increasing the long wavelength range sensitivity,
It is also possible to add elements such as germanium and tin.

In the present invention, the charge generation layer preferably contains silicon as a main component and contains 1 to 40 atom%, preferably 5 to 20 atom% of hydrogen. The thickness is set in the range of 0.1 to 30 μm, preferably 0.2 to 5 μm.

The conditions for forming the film of the charge generation layer are as follows. That is, the frequency is usually 0 to 5 GHz, preferably ^{5 to 3} GHz, the degree of vacuum during discharge is 10 ^{-5 to 5} Torr (0.001 to 665 Pa), and the substrate heating temperature is 100 to 400 ° C.

In the electrophotographic photoreceptor of the present invention, if necessary,
A surface protective layer for preventing deterioration of the photoreceptor surface due to corona ions may be provided.

EXAMPLES Next, the present invention will be described in detail with reference to Examples and Comparative Examples.

Example 1 An aluminum pipe having a diameter of about 120 mm made of an Al-4 wt% Mg-based alloy was immersed in an aqueous solution of a degreasing agent (FC315, manufactured by Nippon Parkerizing Co., Ltd.) 50 g / at 55 ° C. for 3 minutes.
Washed with water.

As the primary electrolytic bath composition, H ₂ SO ₄ 180 g / and Al ₂ (SO ₄ )
₃ · _14~18H aqueous solution was prepared containing ₂ O 30 g /, at 20 ° C., between the aluminum pipe and the aluminum cathode
A constant DC current (12 V) of 2.0 A · dm ⁻² was applied, and electrolysis was performed for 30 minutes to form a 20 μm-thick porous anodized aluminum oxide film.

Next, the aluminum pipe was sufficiently washed with distilled water, and then metal was deposited by secondary electrolysis using a carbon counter electrode. CoSO as secondary electrolysis bath composition ₄ · 7H ₂ O 50g /
_{, H 3 BO 3 20g /,} (NH 4) prepared pH4.5 aqueous solution containing ₂ SO ₄ 5g /, the application of the AC effective voltage 14 V. At this time, as shown in Table 1, the application time of the alternating current was variously changed to adjust the amount of the metal deposited in the holes. At the time of energization for 30 minutes, surface layer deposition was observed by visual observation. At that time, the electrolysis operation was terminated. The metal deposited on the surface layer could be easily removed by washing with water.

Each aluminum pipe on which the treated porous anodized aluminum film is formed is ultrasonically cleaned in distilled water,
After drying at 100 ° C., it was set in a vacuum chamber of a capacitively coupled plasma CVD apparatus. This aluminum pipe is maintained at 200 ° C, and 100% silane (SiH ₄ ) gas is introduced into the vacuum chamber at 250 c / min.
c, 3 cc / min of 100 ppm diborane (B ₂ H ₆ ) gas diluted with hydrogen,
Further, 100% hydrogen (H ₂ ) gas was introduced at a rate of 250 cc / min, and the inside of the vacuum chamber was maintained at an internal pressure of 1.5 Torr (200.0 N / m ² ).
Hz high-frequency power, causing glow discharge,
The output of the high frequency power supply was maintained at 350W. In this manner, a 2 μm-thick charge generation layer made of so-called i-type amorphous silicon with high dark resistance containing hydrogen and a trace amount of boron is formed.
An electrophotographic photosensitive member was obtained.

The positive charging characteristics of the obtained electrophotographic photosensitive member were measured. That is, in the case of the photosensitive pair inflow current of 10 μA / cm, the charge potential immediately after charging and the residual potential after exposure to white light were measured, and the charge transportability was evaluated by the value of residual potential / charge potential. Table 1 shows the results.

For comparison, an electrophotographic photosensitive member manufactured in the same manner except that secondary electrolysis was not performed was similarly evaluated. The results are shown in Table 1.

Example 2 The same aluminum pipe as in Example 1 was similarly pretreated and then subjected to primary electrolysis.

An aqueous solution containing 150 g / H ₃ PO ₄ was prepared as the primary electrolytic bath composition. At 20 ° C., a constant direct current (100 V) of 2.0 A · dm ⁻² was applied between the aluminum pipe and the aluminum cathode.
, And electrolyze for 30 minutes, then in the same electrolyte to facilitate the deposition of metal by secondary electrolysis.
A constant DC voltage of 15 V was applied for 5 minutes. As a result, the film thickness 2
A 0 μm porous anodized aluminum film was formed.

Next, the aluminum pipe was sufficiently washed with distilled water, and then metal deposition was performed by secondary electrolysis. As secondary electrolysis bath _{composition, NiSO 4 · 6H 2 O 80g} /, H 3 BO 3 20g /,
Prepare a pH4 aqueous solution containing tartaric acid 10g /, effective voltage 15V
Was applied. At that time, as shown in Table 2, the application time of the alternating current was variously changed to adjust the amount of the metal deposited in the holes. At the time of energization for 45 minutes, surface layer deposition was observed by visual observation, and the electrolysis operation was terminated at that time.

On the formed porous anodized aluminum film,
A charge generation layer was formed in the same manner as in Example 1, and an electrophotographic photosensitive member was manufactured. These electrophotographic photosensitive members were evaluated in the same manner as in Example 1. Table 2 shows the results.

For comparison, an electrophotographic photosensitive member manufactured in the same manner except that secondary electrolysis was not performed was similarly evaluated. The results are shown in Table 2.

As is clear from the results described in Tables 1 and 2,
The precipitation height of the metal in the pores of the porous anodized aluminum coating is in the range of 1/100 to 1/2 of the height of the pores,
It can be seen that both the chargeability and the charge transportability are compatible, and that the charge transport layer is excellent overall.

Effect of the Invention The electrophotographic photoreceptor of the present invention has, as a charge transport layer, a layer composed of a porous anodized aluminum film containing a filler metal, and the metal has a pore height from the bottom of the pore in the pores of the film. It is deposited up to 1/100 to 1/2 position, and has a structure in which the charge generation layer is directly provided on it, so it has high sensitivity and rich color, high chargeability and dark decay Is low, and the residual potential after exposure is low, and its charging characteristics are not affected by changes in the atmosphere of the external environment, and form images of excellent image quality even when used repeatedly. . In addition, the adhesion and adhesion between the charge transport layer and the charge generation layer are extremely high, the mechanical strength and hardness are high, and the number of defects is small. Therefore, the electrophotographic photoreceptor of the present invention has excellent durability. .

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of one embodiment of the electrophotographic photosensitive member of the present invention. DESCRIPTION OF SYMBOLS 1 ... Support, 2 ... Porous anodized aluminum film, 3 ... Charge generation layer, 4 ... Metal.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takeshi Ebihara 1-34-1 Kambara, Kambara-cho, Anbara-gun, Shizuoka Prefecture Inside Nikkei Giken Co., Ltd. (72) Inventor Yasunobu Iwata 3--13 Mita, Minato-ku, Tokyo No. 12 Nippon Light Metal Co., Ltd. (56) References JP-A-57-88458 (JP, A) JP-A-63-116162 (JP, A) JP-A-63-316060 (JP, A)

Claims (3)

(57) [Claims] 1. A porous anode comprising at least a support, a charge transport layer and a charge generation layer, wherein the charge transport layer is formed by anodizing a support having at least a surface made of aluminum or an aluminum alloy. An electrophotographic photosensitive aluminum oxide film, wherein a metal is deposited in the pores of the porous anodized aluminum oxide film from the bottom of the hole to a position of 1/100 to 1/2 of the height of the hole. body. 2. The method according to claim 2, wherein the metal filled in the holes is Fe, Ni, Co, S
2. The electrophotographic photoconductor according to claim 1, wherein the electrophotographic photoconductor is at least one selected from n, Cu, and Zn. 3. A support having at least a surface made of aluminum or an aluminum alloy is formed on an inorganic polybasic acid selected from sulfuric acid, phosphoric acid, chromic acid, or the like, or an organic polyacid selected from oxalic acid, malonic acid, tartaric acid, or the like. Immerse in a 1 to 30% by weight aqueous solution of a basic acid, apply a direct current of 0.1 to 10 A · dm ⁻² to form a porous anodized aluminum film on the support by anodic oxidation, Performing electrolysis in a solution containing one or more metal salts selected from Ni, Co, Sn, Cu and Zn and an inorganic or organic ion acting as a complexing agent for the metal; Metal is deposited in the pores of the porous anodized aluminum film from the bottom of the hole to 1/100 to 1/2 the height of the hole, and then charge transport consisting of the formed metal-filled porous anodized aluminum film Forming a charge generation layer on the Process for producing an electrophotographic photoreceptor characterized by.