JP2595575B2 - Manufacturing method of electrophotographic photoreceptor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor, and more particularly to a method for producing an amorphous silicon-based electrophotographic photoreceptor.

2. Description of the Related Art In recent years, an electrophotographic photoreceptor having a vapor-deposited layer mainly composed of amorphous silicon as a photosensitive layer has attracted attention. This means that amorphous silicon itself has the potential to fundamentally improve the life factor of conventional electrophotographic photoreceptors, and by applying it to electrophotographic photoreceptors, electrically stable repetition characteristics can be achieved. It has the potential to provide a high hardness, thermally stable and long life electrophotographic photoreceptor, and various amorphous silicon-based electrophotographic photoreceptors have been proposed by focusing on these points. Have been.

Among them, as a photosensitive layer, a so-called charge generation layer that generates charge carriers by light irradiation, and a charge transport layer that can efficiently inject charge carriers generated in the charge generation layer and can move efficiently, so-called, An amorphous silicon-based electrophotographic photoreceptor having a function-separated type photosensitive layer has been proposed as an excellent one. As the charge transport layer in such a function-separated type amorphous silicon-based electrophotographic photoreceptor, for example,
Glow discharge decomposition of a mixed gas of a silane compound gas such as silane and disilane, and a gas containing carbon, oxygen or nitrogen and a trace amount of a group III or group V element-containing gas, to form amorphous silicon containing the above elements What has formed the film is used.

Problems to be Solved by the Invention In general, in an electrophotographic photoreceptor having a function separated into a charge transport layer and a charge generation layer, the chargeability of the charge transport layer itself is the largest in the photosensitive layer. Contribute, the chargeability of the electrophotographic photoreceptor using the hydrogenated amorphous silicon film obtained by glow discharge decomposition of the silane compound,
It is about 30 V / μ or less, which is not yet sufficient. The dark decay rate varies depending on use conditions, but is generally at least about 20% / sec, which is extremely high. Therefore, the electrophotographic photoreceptor having such an amorphous silicon-based charge transport layer is not suitable for use in a relatively high-speed system, or because a sufficient charge potential cannot be obtained, a specific development There was a problem that a system was required. Further, in order to increase the charge potential, the thickness of the charge transport layer may be increased, but for that purpose, the production time must be increased. Accordingly, there is a problem that the probability of occurrence of film defects increases, the yield decreases, and the cost of the photoconductor becomes 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 a method for manufacturing an electrophotographic photoreceptor having a novel charge transport layer. That is, an object of the present invention is to provide a method for producing an electrophotographic photoreceptor having a charge transport layer having excellent transparency, less cracks, and high hardness.

Means and Action for Solving the Problems The inventors of the present invention have previously found that an aluminum oxide film has a function as a charge transport layer. It has been found that when a film is formed, more excellent physical properties and electrophotographic properties can be obtained, and the present invention has been completed.

The present invention provides a method for producing an electrophotographic photoreceptor, comprising the steps of forming a charge generation layer mainly composed of amorphous silicon on a support, and then forming a charge transport layer mainly composed of aluminum oxide. The method is characterized in that the charge transport layer is formed by an ion plating method while introducing oxygen gas.

 Hereinafter, the present invention will be described in detail.

In the present invention, as the support, any of a conductive support and an insulating support can be used.When an insulating support is used, at least the surface in contact with another layer is subjected to conductive treatment. It is necessary to be. Examples of the conductive support include metals or alloys such as stainless steel and aluminum, and examples of the insulating support include:
Examples include synthetic resin films or sheets of polyester, polyethylene, polycarbonate, polystyrene, polyamide, and the like, glass, ceramic, paper, and the like.

A charge generation layer containing amorphous silicon as a main component is formed on the support, and this layer 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 formation methods are appropriately selected according to the purpose, but a method of decomposing silane or a silane-based gas by glow discharge by a plasma CVD method is preferable, and according to this method, an appropriate amount of hydrogen is contained in the film. A film with relatively high dark resistance and high light sensitivity 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 a source gas for forming the charge generation layer containing silicon as a main component include silanes such as silane and disilane, and a gas obtained by using a silicon crystal. Also, when forming the charge generation layer, if necessary,
It is also possible to use a carrier gas such as hydrogen, helium, argon, or neon. A dopant gas such as diborane (B ₂ H ₆ ) gas or phosphine (PH ₃ ) gas can be mixed into these source gases, and an impurity element such as boron or phosphorus can be added to the film. Further, a halogen atom, a carbon atom, an oxygen atom, a nitrogen atom, or the like may be contained for the purpose of increasing the dark resistance, the light sensitivity, or the charging ability. Further, it is also possible to add elements such as germanium and tin for the purpose of increasing the sensitivity in the long wavelength region.

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

In addition, the film formation conditions are, for example, an AC discharge, a frequency of 50 Hz.
~ 5GHz, reactor internal pressure 10 ^-4 ~ 10Torr, discharge power 10 ~ 2000
W, the support temperature is appropriately set in the range of 30 to 600 ° C. The thickness of the charge generation layer can be appropriately set by adjusting the discharge time.

On the charge generation layer, a charge transport layer mainly composed of an aluminum oxide is formed. This layer transmits visible light and has substantially photosensitivity in a visible light region. It does not. In addition, it may have light sensitivity to ultraviolet light.

This charge transport layer needs to be formed by an ion plating method. As a raw material, a compound such as aluminum simple substance and aluminum oxide is used. More specifically, a raw material is inserted into a water-coolable oxygen-free copper crucible provided in a vacuum chamber of an ion plating apparatus. The film formation conditions are as follows: the degree of vacuum in the vacuum chamber is 10 ^-6 to 10 ^-7 Tor.
r, the applied voltage to the ionization electrode +1 to 500 V, the bias applied voltage to the substrate 0 to -2000 V, the electron gun voltage 0.5 to 50 KV, and the electron gun current 1 to 1000 mA. The substrate temperature is 20 ~ 100 ℃
Set to.

In the present invention, oxygen gas is separately introduced directly into the vacuum chamber, but the amount of oxygen gas introduced can be regulated by the oxygen gas pressure in the vacuum chamber. That is, after the inside of the vacuum chamber is evacuated to the above-mentioned degree of vacuum, oxygen gas is exhausted to a degree of vacuum
^-6 to 10 ² Torr, preferably 10 ^-4 to 10 ^-1 Torr. In this case, if the introduced amount of oxygen gas is small, the transparency of the formed film is reduced, while if the introduced amount of oxygen gas is large, cracks generated in the formed film are reduced. However, an excessive amount of oxygen gas makes the film excessively soft, so it is necessary to set the oxygen gas in an appropriate range.

The thickness of the charge transport layer can be appropriately set by adjusting the ion plating time. In the present invention, the thickness is set in the range of 2 to 100 μm, preferably 3 to 30 μm.

In the production of the electrophotographic photoreceptor of the present invention, if necessary, another layer may be formed adjacent to the upper or lower part of the set of the charge generation layer and the charge transport layer. Examples of these layers include the following.

As a charge injection blocking layer, for example, a p-type semiconductor layer or an n-type semiconductor layer obtained by adding an element of Group III or Group V of the periodic table to amorphous silicon, or silicon nitride, silicon carbide, silicon oxide, amorphous An insulating layer of carbon or the like, as an adhesive layer, nitrogen,
A layer formed by adding carbon, oxygen, or the like can be given. Others
Layers that can control the electrical and image characteristics of the photoreceptor, such as a layer that simultaneously contains a Group IIIB element and a Group V element of the periodic table of the elements. The thickness of each of these layers can be arbitrarily determined, but is usually set in the range of 0.01 μm to 10 μm.

Further, a surface protective layer for preventing deterioration of the photoreceptor surface due to corona ions may be provided.

Each of the above layers can be formed by a plasma CVD method. As described in the case of the charge generation layer, when impurity elements are added, a gaseous substance containing the impurity element is introduced into a plasma CVD apparatus together with a silane gas to perform glow discharge decomposition. Either an AC discharge or a DC discharge can be effectively used as a film forming means of each layer. In the case of an AC discharge, for example, the film forming conditions are as follows. That is, the frequency is usually 0.1
~ 30MHz, preferably 5 ~ 20MHz, the degree of vacuum during discharge is 0.1 ~ 5
Torr (13.3 to 66.7 Pa), substrate heating temperature is 100 to 400 ° C.

Examples Hereinafter, the present invention will be described with reference to examples.

Example 1 An a-Si: H film having a thickness of 1 μm was formed on an aluminum pipe having a diameter of about 120 mm. That is, capacitively coupled plasma
Introduce 200 cc / min silane gas into the CVD system and set the pressure to 1.5 Torr
r. Glow discharge decomposition was performed at a support temperature of 250 ° C. and a high frequency output of 13.56 MHz at 300 W for 10 minutes.

Next, the above aluminum pipe was placed in a vacuum chamber of an ion plating apparatus, and 99.99% of alumina (Al
₂ O ₃ ) is charged into a water-cooled oxygen-free copper crucible in a vacuum chamber, evacuated by a vacuum pump to a degree of vacuum of 1 × 10 ^-6 Torr, and then oxygen is reduced to a degree of vacuum of 2 × 10 ^-4 Torr Gas was introduced. A voltage of 8.5 KV was applied to the electron gun, and the power output was set so that the current became 240 mA. At this time, the voltage of the ionization electrode was set to 80 V, and a bias voltage of -500 V was applied to the substrate itself. The output of the electron beam was controlled by a quartz crystal film thickness monitor installed near the aluminum pipe so that the deposition rate was constant at 34 ° / sec. In this way, about
Film formation was performed for 25 minutes to form a charge transport layer made of an aluminum oxide film having a thickness of about 5 μm.

When the sample was taken out of the vacuum chamber and the charge transport layer was examined, the formed aluminum oxide film was transparent,
It was confirmed that the number of cracks (cracks) in the film was also small. Further, the Vickers hardness (load: 10 g) was 680, indicating a high hardness.

Example 2 An electrophotographic photosensitive member was manufactured in the same manner as in Example 1 except that oxygen gas was introduced until the degree of vacuum reached 7 × 10 ⁻⁴ Torr. The formed charge transport layer was transparent and had less cracks. Also, Vickers hardness (load
10g) was also 500.

Comparative Example An electrophotographic photosensitive member was manufactured in the same manner as in Example 1 except that oxygen gas was not introduced. The formed charge transport layer was black, and the film had many cracks.
The Vickers hardness (load 10 g) was 200, and the strength was poor.

Effects of the Invention According to the present invention, an electrophotographic photoreceptor having a novel charge transporting layer having excellent transparency, less cracking and high hardness can be produced using aluminum or a compound thereof. Therefore, the electrophotographic photosensitive member manufactured according to the present invention has excellent durability and excellent electrophotographic characteristics.

Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C23C 16/50 C23C 16/50 (72) Inventor Kenichi Karakida 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Fujize Rocks Co., Ltd. In-house (56) References JP-A-62-254158 (JP, A)

Claims (3)

(57) [Claims] 1. An electrophotographic photoreceptor comprising a step of forming a charge generation layer mainly composed of amorphous silicon on a support and then forming a charge transport layer mainly composed of aluminum oxide. A method for producing an electrophotographic photoreceptor, wherein the charge transport layer is formed by ion plating while introducing oxygen gas. 2. The method for producing an electrophotographic photoreceptor according to claim 1, wherein Al ₂ O ₃ is used as a raw material. 3. The method for producing an electrophotographic photosensitive member according to claim 1, wherein aluminum is used as a raw material.