JPH0762763B2 - Electrophotographic photoreceptor - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electrophotographic photosensitive member using amorphous silicon as a photoconductive material.

BACKGROUND ART Conventionally, inorganic materials such as Se and ZnO and organic materials such as poly-N-vinylcarbazole and trinitrofluorenone have been used as photoconductive materials in electrophotographic image forming members. Amorphous silicon (hereinafter referred to as “a-Si”) has begun to attract attention. This is because the electrophotographic photosensitive member using a-Si as a photoconductive layer has characteristics similar to or better than those of conventional ones, is harmless to humans and the environment, and has extremely high durability. This is because it has advantages such as

However, in the conventional a-Si electrophotographic photoreceptor, the layer strain when forming the a-Si layer on the support is large,
Further, since the adhesion between the support and the a-Si layer is insufficient, there remains a big problem that the a-Si layer floats from the surface of the support, peels off, or cracks. As a solution to this, the methods (1) to (3) have been conventionally performed. That is, (1) a crystalline silicon layer is provided between the support and the a-Si layer to form a photoconductive layer, and the crystalline silicon layer improves the adhesion between the support and the a-Si layer. (Japanese Patent Application Laid-Open No. 57-44154); (2) The surface of the support is made of aluminum oxide (AI ₂ O ₃ .nH ₂ O; n = 1, 3) containing water in a chemical structure, and the support and a- Si
Improving adhesion to a layer (Japanese Patent Laid-Open No. 57-104938); (3) Providing an a-Si layer auxiliary layer containing a nitrogen atom as a constituent atom between the support and the a-Si layer. , This auxiliary layer improves the adhesion between the support and the a-Si layer (JP-A-58-14905).
However, the methods (1) to (3) described above still have the following problems. That is, in the case of the method (1), when the crystalline silicon layer is formed on the support, it is necessary to raise the temperature of the support, and therefore the support is largely damaged and the constituent atoms of the support are further increased. When the method (2) is used, OH groups and oxygen atoms, which are the constituents of water, diffuse into the a-Si layer and diffuse for a long time. In the case of the method (3), since the auxiliary layer itself is hard and the adhesion between the auxiliary layer and the support cannot be said to be good, the properties of the auxiliary layer and the support may be deteriorated. However, problems such as peeling and floating could not be resolved.

Aim The present invention is a- without deterioration of characteristics as an electrophotographic photoreceptor.
By improving the adhesion between the Si layer and the support, floating or peeling of the a-Si layer, preventing the occurrence of cracks, repeated stability, with the aim of providing an electrophotographic photoreceptor having stability over time. To do.

Constitution The present invention provides an electrophotographic photosensitive member having an amorphous layer containing silicon atoms as a matrix on a support and containing at least one of a hydrogen atom and a halogen atom, wherein the support and the amorphous layer are provided. The electrophotographic photosensitive member is characterized in that it has a porous aluminum oxide layer between the two, and when the porous aluminum oxide layer is sealed, a material made of silicide is used as a sealing material.

The inventors of the present invention have conducted research on an a-Si-based electrophotographic photosensitive member. However, a porous aluminum oxide layer is provided between a support and an a-Si layer, and pores of the porous aluminum oxide layer are provided. It was confirmed that the desired characteristics were maintained for a long time by sealing the material with a material composed of silicide. The present invention has been completed based on such findings.

Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a basic layer structure of an electrophotographic photosensitive member according to the present invention, in which 1 is a conductive support and 2 is a porous aluminum oxide layer sealed with a silicide material,
2'is a silicide material and 3 is an a-Si layer.

Here, the generation and structure of the porous aluminum oxide layer in the present invention will be briefly described.

When aluminum is used as an anode and electrolyzed in a certain electrolytic bath, an oxide film is formed on aluminum, but due to the difference in the type of electrolytic bath, a barrier type film and a porous type film (alumite) are formed. It The former is formed in an acidic electrolytic bath having a small ability to chemically dissolve aluminum oxide, such as an aqueous boric acid / sodium borate solution, and the latter is formed in an acidic electrolytic bath having a large ability to chemically dissolve aluminum oxide, such as an aqueous sulfuric acid solution. Form. The hexagonal column model has been proposed as the oxide film structure of the porous film (alumite), and the pore size of this is shown in the table-
1 [F.keller, MSHunter and DLRobi
nson; J. Electrochem. Soc., 100, 411 (1953)].

When the porous film (alumite film) is sealed with steam or boiling water, a hydrate is formed on the surface of the film and the wall surface of the pore according to the following reaction formula, and the mouth outside the pore is blocked. This hydrate is called boehmite and forms at 80 ° C or higher.

Al ₂ O ₃ + H ₂ O → Al ₂ O ₃ · H ₂ O (boehmite) In the present invention, such a porous aluminum oxide layer 2 is provided on the support 1, and the silicide material 2 ′ is used as a sealing material. Used to seal the pores of the porous aluminum oxide layer and expose the surface of the support, thereby removing silicide by etching or the like, and further depositing the a-Si layer 3 thereon. Is.

The electrophotographic photosensitive member thus formed has the following advantages as compared with the conventional electrophotographic photosensitive member using the pore-sealed aluminum oxide layer.

B) Since H ₂ O chemically contained in the aluminum oxide layer 2 exists only in the pore wall, its content is extremely small. Therefore, the amount of H ₂ O that becomes an OH group or an oxygen atom and diffuses into the a-Si layer 3 can be ignored, and the characteristics of the electrophotographic photosensitive member are stable for a long time. Further, the release of H ₂ O from the aluminum oxide layer 2 is extremely small even at high temperatures (stable at 600 ° C. or lower), so that pinholes, cracks and the like due to strain do not occur.

(B) Since it is an unsealed hole, the silicide material also enters the pores, and the adhesion effect between the support 1 and the silicide material is remarkably improved by the anchor effect. Since the number of pores per unit area is very large as can be inferred from Table 1, the anchor effect is remarkable.

Furthermore, when aluminum is used as the metal used to form the silicide material and AlSi is used as the silicide, a chemical bonding force is generated because a common atom of aluminum exists between the aluminum oxide layer and the silicide material. Adhesion between the aluminum oxide layer and the silicide material is improved.

C) When the pores of the porous aluminum oxide layer are sealed with a silicide material and the a-Si layer is further deposited thereon, the silicide is structurally an alloy of silicon and a metal. Common constituent atoms, that is, Si atoms, exist between the silicide material and the a-Si layer. This improves the adhesion between the silicide material and the a-Si layer and improves the matching of the lattice constants at the interface, significantly improving the structural and electrical adhesion. The trap density for photo carriers at the interface between the a-Si layer and the support is reduced,
The electrophotographic characteristics are improved.

D) Various effects are expected by appropriately selecting the metal used for the silicide and the metal forming the surface of the support. For example, when the metal on the surface of the support is Al, Cr, Mo, or Ti, if Pt or the like is used when forming the silicide, the contact resistance at the bonding interface becomes an ohmic contact, so electrophotography The photosensitivity in the characteristics is improved.

Further, when the support body is aluminum or an aluminum alloy, if aluminum is used as the silicide material, the adhesiveness between the support body and the silicide material is improved. It has a band gap, so
If Al belonging to Group I is used as a silicide, Al acts as an acceptor and the silicide becomes P-type. Therefore, the aluminum oxide layer sealed with the silicide material also acts as a blocking layer for preventing the injection of free carriers from the support 1, so that the maximum surface potential increases when considered as an electrophotographic photoreceptor. And the charge potential characteristics such as dark decay are reduced.

It is preferable to use aluminum or aluminum alloy as the conductive support 1 in the electrophotographic photosensitive member of the present invention. A film thickness of 0.1 ~ is obtained by anodic oxidation on a conductive support.
A porous aluminum oxide layer 2 having a thickness of about 2 μm is formed, and then a sputtering method, an alloy reaction method, a CVD method, etc.
The silicide material 2'is used as a sealing material to seal the pores of the porous aluminum oxide layer to expose the surface of the support, and the silicide is removed by etching or the like, if necessary. , Known methods such as sputtering, ion plating, etc.
The a-Si layer 3 is usually formed in a thickness of 1 to 100 μm, preferably 2 to 50 μm.

Next, examples will be shown.

Example An electrophotographic photosensitive member was prepared by the following steps.

After polishing the surface of a cylindrical conductive support (hereinafter referred to as "Al drum") made of A3003 aluminum (hereinafter referred to as Al), thoroughly washed and immersed in a 10% NaOH aqueous solution at room temperature, Then, the surface of the Al drum was degreased by immersing it in a 30% HNO ₃ aqueous solution.

As shown in FIG. 2, the degreased Al drum 6 is immersed in the electrolytic solution 5 contained in the bath 4. 15wt% as electrolyte
A H ₂ SO ₄ aqueous solution was used.

A cathode plate 7 having an area equal to or larger than the outer peripheral side surface of the Al drum 6 is immersed in the electrolytic solution 5 so that the Al drum faces each other. A Pt plate was used as the cathode plate 7.

A power source 8 is connected so that the Al drum 6 and the cathode plate 7 serve as an anode and a cathode, respectively. A DC power supply was used as the power supply 8.

The Al drum 6 was anodized (for several minutes) at room temperature.
At this time, the voltage of the power supply 8 is adjusted while observing the display on the ammeter 9 so that the current density is constant at about 10 mA / cm ² . In addition,
Since the aluminum oxidation reaction causes heat generation and gas generation, the electrolytic solution 5 was cooled and stirred. The stirring here is also necessary to form a uniform film.

After the anodization was completed, the Al drum was pulled up from the electrolytic solution 5 and washed with flowing pure water for at least 10 minutes. If the electrolytic solution remains in the pores, it adversely affects the characteristics of the electrophotographic photosensitive member, and therefore it is necessary to perform sufficient cleaning.

After washing, the porous anodized aluminum layer (alumite layer) formed on the surface of the Al drum was dried. The film thickness of the alumite layer was about 0.5 μm.

Then, as shown in FIG. 3, the Al drum 10 on which a porous anodized aluminum layer (alumite layer) is formed is placed in a chamber.
It is fixed to a support jig 12 in 11 and rotated by a drum rotation motor 13.

The heater 14 and the temperature controller 15 constantly heat the drum surface temperature at 250 ° C.

Gas cylinder plugs 16, 17 and 18, main valve 19, valve
20 is closed, roughing valve 21 is opened, rotary pump 22
The air in the chamber 11 is exhausted by.

When it is confirmed that the inside of the chamber 11 has reached a predetermined degree of vacuum, the roughing valve 21 is closed, the valve 20 and the main valve 19 are opened, and the oil diffusion pump 23 further evacuates.

After confirming that a predetermined degree of vacuum has been reached, close the main valve 19, open the main valve 16 of each gas cylinder 27, adjust each gas component to a predetermined flow rate while watching the mass flow meter 24, and open the valve 32 to open the chamber. To introduce. The type of gas used here is SiH ₄ (20% based on Ar).

Close valve 20 and open valve 21 to adjust the vacuum to 1 Torr,
While maintaining the drum surface temperature at 250 ° C., high frequency power was applied to the electrode 31 by the high frequency power source 30 to deposit an a-Si layer (including hydrogen atoms) on the surface of the Al drum 10 under the conditions shown in Table 2 below.

After depositing the a-Si layer for about 20 seconds, the support on which the a-Si layer was deposited was taken out from the reaction vessel 11, and the film thickness of the a-Si layer was measured and found to be about 200Å.

Keep the temperature of the support at 300-600 ℃ and heat treatment at 120
After that, silicide (AlSi) was formed. In order to expose the surface of the support, the Si film on the surface is removed by etching if necessary, and then the a-Si layer 3 is formed on the support by the following operation using the plasma CVD apparatus shown in FIG. Deposited.

Chamber of Al drum 10 sealed with silicide
It is fixed to a support jig 12 in 11 and rotated by a drum rotation motor 13.

The heater 14 and the temperature controller 15 constantly heat the drum surface temperature at 200 ° C.

Gas cylinder plugs 16, 17 and 18, main valve 19, valve
20 is closed, roughing valve 21 is opened, rotary pump 22
The air in the chamber 11 is exhausted by.

When it is confirmed that the inside of the chamber 11 has reached a predetermined degree of vacuum, the roughing valve 21 is closed, the valve 20 and the main valve 19 are opened, and the oil diffusion pump 23 further evacuates.

After confirming that the specified vacuum level has been reached, close the main valve 19, open the main plugs 16, 17, 18 of the cylinders 27, 28, 29, and check each gas component while observing the mass flow meters 24, 25, 26. And the valve 32 is opened and introduced into the chamber. The types of gas used here are as shown in Table-3.

Close the valve 20 and open the roughing valve 21 to adjust the vacuum to 1T.
High frequency power supply while maintaining orr and drum surface temperature at 200 ℃
High frequency power was applied to the electrode 31 by 30 to deposit an a-Si layer (including hydrogen atoms) on the surface of the Al drum 10 under the conditions shown in Table 4 below.

In forming the a-Si layer 3, oxygen atoms or boron atoms may be added if necessary in order to make the film have high resistance. In this example, oxygen gas was added at a flow rate of 2 SCCM to form the a-Si layer 3. The a-Si layer 3 was deposited for about 6 hours and had a film thickness of about 20 μm.

The characteristics of the electrophotographic photosensitive member thus produced were evaluated by a mounting test, that is, (a) a positive corona discharge was applied at a power supply voltage of 6 KV in the dark, and (b) image exposure was performed with a light amount of 95 lux. The image forming process of forming an electric image, (c) developing with a toner having a negative charge, and transferring and fixing the image on a transfer paper (plain paper) is repeatedly performed to obtain an image on the first transfer paper. The image on the 50,000th transfer paper was compared.

As a result, there was almost no difference in density between the two and no occurrence of abnormal images such as white spots and ghosts. When the electrophotographic photosensitive member after the mounting test was observed, no peeling or cracking of the a-Si layer (including hydrogen atoms) was observed.

Effects As is apparent from the description of the examples, the electrophotographic photosensitive member obtained by the present invention has high quality and high durability and is extremely reliable.

[Brief description of drawings]

FIG. 1 is a sectional view of an electrophotographic photosensitive member according to the present invention, FIG. 2 is a diagram showing anodizing treatment of an aluminum drum in manufacturing the electrophotographic photosensitive member of the present invention, and FIG. 3 is an electrophotographic photosensitive member of the present invention. It is a figure showing the plasma CVD apparatus for manufacturing a body. 1 ... Support, 2 ... Aluminum oxide layer, 2 '... Silicide material, 3 ... a-Si layer, 4 ... Bath, 5 ... Electrolyte, 6 ... Al drum, 7 ... Cathode plate , 8 ... power supply, 9 ...
… Ammeter, 10 …… Al drum after anodizing, 11 ……
Chamber, 12 ... Support jig, 13 ... Drum rotation motor, 14 ... Heater, 15 ... Temperature controller, 16, 17, 18 ...
… Gas cylinder main plug, 19 …… Main valve, 20 …… Valve, 21 …… Roughing valve, 22 …… Rotary pump, 23
…… Oil diffusion pump, 24,25,26 …… Mass flow meter, 2
7,28,29 …… Gas cylinder, 30 …… High frequency power supply, 31 …… Electrode, 32 …… Valve.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-59-58435 (JP, A) JP-A-59-28162 (JP, A) JP-A-59-87462 (JP, A) JP-A-57- 88458 (JP, A)

Claims (1)

[Claims] 1. An electrophotographic photosensitive member having an amorphous layer having a silicon atom as a base material and containing at least one of a hydrogen atom and a halogen atom on a support, the support and the amorphous material. Having a porous aluminum oxide layer between the layers,
An electrophotographic photosensitive member characterized by using a material made of silicide as a sealing material when sealing a porous aluminum oxide layer.