JPS5860747A - Electrophotographic receptor - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic receptor high in sensitivity, by providing an alumina layer and a photosensitive layer of amorphous silicon, and a protective layer of carbon-contg. amorphous silicon on an aluminum alloy substrate. CONSTITUTION:An alumina layer is formed by introducing a prescribed amount of oxygen from a gas flow controller 21 into a reaction chamber 12 evacuated to 10<-3>-10<-9>Torr with a vacuum pump 10, heating a substrate 15 to 200-400 deg.C with a heater 16, applying high frequency voltage between a cathode electrode 13 and an anode electrode 14 from a high frequency source 18 to generate glow discharge, and anodizing the substrate 15. Then, feed of oxygen is stopped, the chamber 12 is evacuated to 10<-3>-10<-6>Torr, and an amorphous silicon photosensitive layer is formed by introducing gaseous SiH4 from a cylinder 26, and generating glow discharge between the electrodes 13, 14. Next, a surface protective layer made of amorphous silicon carbide is formed by introducing gaseous ethylene from a cylinder 28, and causing glow discharge.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor that is highly sensitive and easy to manufacture.

Conventional amorphous silicon (hereinafter referred to as a-81)
FIG. 1 shows the structure of an electrophotographic photoreceptor using . In FIG. 1, reference numeral 1 denotes a substrate, which is usually a metal or glass plate on which transparent electrodes are formed. 2 is a photosensitive layer made of a-8t formed on the substrate l.

A-81 is formed by glow discharge decomposition of silane gas (SiHt) or sputtering of crystalline silicon, but the dark resistivity at room temperature of the non-doped one is 10.
It is small, less than 12Ωα. Therefore, if a non-dawg material is used as a photosensitive layer of an electrophotographic photoreceptor, the dark decay is too fast to be of practical use.

Therefore, in order to put the structure shown in Fig. 1 into practical use, a-8i
Attempts have been made to increase the resistivity of the membrane.

9. For example, the flow rate ratio is B for a quick pace 5in4 (10 inch).
An a-8l film has been formed by glow discharge decomposition of a gas to which digerane (BiHa) of sHa/SiH4 to 1O is added and a trace amount of 02 is introduced (Imaging Electronics Engineers of Japan Proceedings 80-04-2. (1980, Nakano et al.), this method allows a-8 with a dark resistivity of 10”Ωσ at room temperature to be
One film can be formed. Then, an electrophotographic photoreceptor having the structure shown in FIG. 1 was manufactured using the A-81 film, and good characteristics were obtained. However, with this method, high resistivity a
When forming -8i, it is necessary to control the introduction of a trace amount of grain and oxygen, and it is particularly difficult to control the trace amount of oxygen.

As described above, according to the above method, it is possible to produce an electrophotographic photoreceptor that can be put to practical use, but the manufacturing method is complicated, and it is difficult to form a photosensitive layer with good reproducibility. FIG. 2 shows the structure of a conventional electrophotographic photoreceptor proposed for use as an a-8it photosensitive layer having a small dark resistivity. Here, 3 is a substrate, and 1 is usually a metal or glass plate on which transparent electrodes are formed. 4 is the substrate 3
A charge injection blocking layer made of n-type or p-type a-8i formed thereon.

Reference numeral 5 denotes a photosensitive layer made of a-8i which is either undoped or doped with several to several tens of ppm of boron, and is formed on the charge injection blocking layer 4 .

When this structure is used with positive charging, p-type a-8i is used for the charge injection blocking layer 4, and when used with negative charging, n-type a-8i is used.
Use i.

In the case of positive charging, the surface of the photosensitive layer 50 is positively charged by the positive corona, but at this time, electrons are injected from the substrate 3 side to neutralize this. Without the charge injection blocking layer 4, the photosensitive layer 5 would have a low dark resistivity, so electrons would flow and sufficient charging would not be achieved, and dark decay would be rapid after charging. On the other hand, when the charge injection blocking layer 4 is present, the substrate 3
The injection of electrons from the inside is blocked, and it has sufficient viewing ability.

A photoreceptor with slow dark decay is realized. It operates similarly well even when negatively charged. However, the characteristics of the charge injection blocking layer 4, the doping amount of impurities when forming n-type or p-type a-8i, and the
-8i, and therefore, when manufacturing a photoreceptor with this structure, the doping amount and film thickness must be accurately controlled, making the manufacturing process complicated. In addition, glow discharge decomposition of silane gas (SiH4), etc.
8i (charge injection blocking layer 4), impurity doping (for d and n type, phosphine (P) is used).
H3), Diporan (Bzl'g4) for p-type
Alternatively, a gas such as arsine (AsH3) is used,
These gases are extremely hot, and the permissible concentration is 8iH4)1
More than an order of magnitude lower.

The present invention is characterized in that an alumina layer formed on an aluminum alloy substrate by anodizing the substrate in an oxygen glow discharge is used as a charge injection blocking layer,
The purpose is to realize an amorphous silicon-based electrophotographic photoreceptor that is easy to manufacture and has high sensitivity.

Embodiments of the present invention will be described below with reference to the drawings. Third
The figure shows an embodiment of the present invention, and 6 is a substrate made of an aluminum alloy. An alumina (At203) layer 7 as a charge injection blocking layer is formed on this substrate 6 by anodizing the substrate 6 in an oxygen glow discharge.

A photosensitive layer 8 made of non-doped a-8i is formed on the alumina layer 7, and the surface of the photosensitive layer 8 is made of a-8i.
Amorphous silicon carbide (a-8i1-xCx), which is formed by adding carbon (C) to i, is formed as the surface protective layer 9.

FIG. 4 shows an example of a glow discharge device used for manufacturing such an electrophotographic photoreceptor.

In this figure, there are 10 vacuum pumps, 11 stop pumps,
Pal 7'', 12 is the reaction amount, 13 is the cathode electrode, 14 is the anode electrode, 15 is the substrate, 16 is the heater, L7
Stop pulp, L8 is high frequency w source, 191dDc
Power supply, 20, 21.22ff gas flow control 9.2
3.24.25 is a pressure regulating valve, 26 is a silane gas cylinder, 27 is an oxygen gas cylinder, and 28 is an ethylene gas cylinder.

The case where an electrophotographic photoreceptor having the structure shown in FIG. 3 is manufactured using this apparatus will be described. First, the inside of the reaction chamber 12 is blown to IO-3 to IQ-'torr by the vacuum pump 10, and then the gas flow rate is controlled to ? At 21 o'clock, oxygen was introduced at a flow rate determined in advance in the experiment. On the other hand, the substrate 15 is heated to a temperature of 200 to 400 by heating the heater 16.
'C, preferably heated to 250-300°C. After the gas flow and substrate temperature have stabilized, the high frequency power source 18 applies high frequency power between the cathode electrode 13 and the anode electrode 14.

Generates a glow discharge. Then, due to the glow discharge, the oxygen is decomposed into radical oxygen atoms.

M alloy substrate 15t - oxidize. At this time, if a constant voltage is applied between the cathode electrode 13 and the anode electrode 14 by the DC power supply 19, the thickness of the dioxide film increases.

By this method, an aluminum oxide film (alumina layer) with a suitable thickness (several hundred to several thousand) is formed.

The formed alumina layer is homogeneous and of good quality with few pinholes.

Next, stop the pulp of the oxygen gas pump 27.

Once inside one reaction chamber 12, l O-3 to l Q-' tor
Preferably evacuate to 1O-5 to 10-' torr.
Next, 5jH4 gas is introduced at a constant flow rate using the silane gas pump 26 and the silane gas flow controller 20. next,
A high frequency power source 18 applies high frequency power between the luminous poles to generate glow discharge. Due to this glow discharge j) 5f
H4 gas is decomposed and a-
8i (photosensitive layer) is formed. The film thickness of this a-8t is
The thickness ranges from several μm to several tens of μm depending on the purpose of use.

Finally, after a-8i of appropriate thickness is formed.

Ethylene gas is introduced into the reaction chamber 12 at an appropriate flow rate ratio to silane gas, and high frequency power is applied to generate glow discharge to form amorphous silicon carbide (a-8h-, (Cx) as a surface protective layer. ) to form.

By the above procedure, the electrophotographic photoreceptor shown in FIG. 3 is formed.

The present inventor created the electrophotographic photoreceptor shown in Fig. 3 with six aluminum layers =
lOOoX, a-8i layer~7μm, a
-8i1-zcx (8iL/C! H4=1)
~l OOOA - Formed on a sialuminium alloy substrate according to the above procedure.

Positive charging saturation surface potential ~400V, dark decay half time ~2
Good characteristics were obtained, with a photosensitivity peak at 700 nm light at 0 seconds and a photosensitivity of 4 cd/μJ.

Next, the a-8 used in the electrophotographic photoreceptor shown in FIG.
The effect of the surface protective layer 9 made of + and -xcX will be described. a-811-XCX has a 1 composition ratio X of 0.4 to 0.8
For about 2.2 = -2, the optical bandgap is 2.2 = -2,
8eV, dark resistivity is 1019h or more, hardness is a-8
It is even larger than i. Furthermore, according to the findings of the present inventor, electron injection into Cx (a-8i7>ra a-5ix-) is carried out without any hindrance. Therefore, it is used for positive charging with light having a wavelength of about 500 nm or more. Case 2: The surface protective layer 9 has a thickness of about 1 μm, which poses no problem and is expected to be sufficiently effective as a protective layer against mechanical friction.

Next, the manufacturing process of the electrophotographic photoreceptor (C) is the third step.
It is relatively safe because it does not require the use of highly poisonous gases such as gas. Furthermore, when forming the alumina layer 7 which acts as a charge injection blocking layer, it is easy to control the thickness of the alumina layer 7). J, F, 0'Hanlon's report (J.

ElecAchem, Soc, 118 (1970)
According to 270).

The alumina layer formed on the sialuminium by constant voltage plasma anodic oxidation is determined by the DC voltage applied between the electrodes, and oxidation does not proceed beyond a certain period of time. Therefore, the film thickness ij and the DCkfL pressure can be determined, and their control is easy. Furthermore, since the photosensitive layer 8 is non-doped, there is no need to control the amount of doping or the amount of oxygen in the film. According to the inventor's experiments, as long as the dark resistivity of a-8i is 10109Q or more, there is almost no effect on the charging characteristics and dark decay time.
-8i formation conditions are also loosely constrained.

As explained above, in the embodiment, the alumina layer 7 formed by plasma anodizing an aluminum alloy is used as the charge injection blocking layer, the non-doped a-8i is used as the photosensitive layer 8,
ill -81l-) (Compared to the conventional structure because it has a structure in which Cx is used as the surface protective layer 9.

There is an advantage that there is no need to control minute amounts of dopants, oxygen, etc. for forming n-type and p-type a-8i, and manufacturing is easy. Furthermore, the thickness of the alumina layer 7 can be easily controlled by applying a constant voltage.
Restrictions on the dark resistivity of the i-photosensitive layer 8 are also greatly relaxed since it only needs to be lo'b or more. Also, a -5i1
-) (Since Cx is formed on the surface to a thickness of about 1 μm, it is extremely resistant to damage caused by mechanical friction, etc. Furthermore, PHs.

B! Since there is no need to use violent gases such as H6 and ASH3, it is safe during production.

In the example, the entire photosensitive layer 8 was formed using non-doped a-8i, but the photosensitive layer 8 may also be formed using a-8i doped with germanium.

As is clear from the above, the present invention is an electrophotographic photoreceptor using an aluminum alloy plasma anodized film (alumina layer) as a charge injection blocking layer.

This has the advantage of simplifying the manufacturing process and providing high sensitivity. Therefore, 1 example.

It can be used as a photoreceptor for printers or copiers.

[Brief explanation of drawings]

1 and 2 are structural sectional views of a conventional electrophotographic photoreceptor, and FIG. 3 shows an embodiment of the electrophotographic photoreceptor of the present invention.
The j-plane view and FIG. 4 are configuration diagrams of a manufacturing apparatus used for manufacturing a photoreceptor according to an embodiment of the present invention. 6... Aluminum alloy substrate, 7... Alumina layer. g...-a-8i photosensitive layer, 9 ・a-8il-
) (Surface protective layer consisting of Cx. Figure 1 Figure 2 Figure 3

Claims (2)

[Claims] (1) An aluminum alloy substrate, an alumina (MsO@) layer formed on the substrate by anodizing this substrate in an oxygen glow discharge, and amorphous silicon or germanium on amorphous silicon. 1. An electrophotographic photoreceptor comprising: a layer containing the alumina added thereto, and a photosensitive layer formed on the alumina layer. (2) The electrophotographic photoreceptor according to claim 1, characterized in that a layer of amorphous silicon to which carbon is added is laminated on the surface of the photosensitive layer.