JPH02165161A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain high surface potential by forming in an a-SiC photoconductive layer a layer region containing carbon in a content distribution decreasing in the layer thickness direction from a substrate to the surface of the photosensitive body. CONSTITUTION:The electrophotographic sensitive body is formed by successively laminating on the conductive substrate 1 the amorphous silicon carbide (a-SiC) photoconductive layer 2 having a function of generating charges, and an organic semiconductor layer 3 having a function of transferring charges, and the layer 2 has the layer region containing carbon in a content distribution decreasing in the layer thickness upward direction, thus permitting high surface potential to be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor comprising a laminated layer of an amorphous silicon carbide conductive layer and an organic optical semiconductor layer.

[Prior art and its problems]

The photoconductive material of the electrophotographic photoreceptor includes Se+5e-Te, Δ
There are inorganic materials such as 5□Sa:++ZnO+CdS and amorphous silicon, of which Se was first put into practical use, and ZnOrCdS+amorphous silicon was also put into practical use.

On the other hand, PVK was first put into practical use as an organic photoconductive material, and later a functionally separated photoreceptor was proposed in which charge generation and transport were shared between separate materials, and this photoreceptor led to the rapid development of organic materials. It developed rapidly.

On the other hand, inorganic light guide? i! An electrophotographic photoreceptor in which an organic photoconductor layer is laminated on top of the layer has also been proposed.

For example, there is a laminated photoreceptor consisting of a Se layer and an organic optical semiconductor layer, which has already been put into practical use, but this photoreceptor has the disadvantage that Se itself is harmful and has poor sensitivity on the long wavelength side. Ta.

Therefore, amorphous silicon carbide light guide 1iN (
Under Ju, amorphous silicon force - byte a-3i
A laminated photoreceptor was proposed (Japanese Unexamined Patent Application Publication No. 14241/1983) consisting of an organic optical semiconductor layer (abbreviated as C) and an organic optical semiconductor layer, which solved the above problems and achieved non-polluting properties and high photosensitivity.

However, the present inventors have proposed a -S i as described in 1.
When we fabricated an am-type photoreceptor consisting of a C layer and measured its surface potential, we were unable to obtain satisfactory characteristics.
It became clear that further improvements were needed.

Therefore, an object of the present invention is to provide an electrophotographic photoreceptor with a high surface potential.

[Means for solving problems]

In the electrophotographic photoreceptor of the present invention, when an aSiC photoconductive layer and an organic semiconductor layer are sequentially laminated on a conductive substrate, carbon is added to the a-3iC photoconductive layer from the substrate to the 16-photoconductor surface in the layer thickness direction. It is characterized by forming a NmW region in which the content gradually decreases.

The present invention will be explained in detail below.

FIG. 1 shows the layer structure of the electrophotographic photoreceptor of the present invention.
According to the figure, an a-3iC photoconductive layer (2) and an organic photoconductive layer (3) are sequentially laminated on a conductive substrate (1), and an a-SiC photoconductive layer (a). 2) has the function of charge generation, and the other organic light + conductor sequence (3)
has a function called charge transport.

The present invention is characterized in that a layer region in which the carbon content gradually decreases is formed in the a4xc photoelectric layer (2), thereby increasing the surface potential.

The carbon content distribution of such a SiC photoconductive layer (2) is shown, for example, in FIGS. 2 to 1.

In these figures, the horizontal axis is the layer thickness direction, the vertical axis is the amount of carbon, and a is the diagonal surface with the substrate (1).
b represents the interface with the organic optical semiconductor layer (3).

Moreover, when the element ratio of this a-3iC photoconductive layer (2) is set as an average value within the range as shown in F, this It
! (2) It is desirable that the photosensitivity of 8i itself be significantly increased.

Composition formula: (Si, -e X) l-y^, (However, L
A is hydrogen or halogen) 0.05 < x < 0.5, preferably 0.1 <
x (0, AO, 1 < y < 0.5, preferably 0.
2 < y < 0.5
When the number is 5 or more, the photoconductivity becomes extremely low, and the excitation function of photocarriers deteriorates.

Furthermore, when the y value is 0□1 or less, the dark conductivity tends to increase. 1. However, the photoconductivity tends to decrease, and therefore the desired photoconductivity cannot be obtained;
When the value is 0.5 or more, the internal stress of the a-SiC layer increases, the adhesion with the substrate decreases, and it becomes easy to peel off at i-7.

Further, the a-SiC photoconductive layer (2) contains hydrogen (II).
Elements and halogen elements are contained for terminating dangling bonds, but among these elements, H element is likely to be incorporated into the terminating portion, which is said to reduce the localized level density in the band gap. - Desirable in terms of points.

The thickness of the a-SiC photoconductive layer (?) is 0.05-5 μm,
It is preferable to set it within the range of 0.1 to 3 .mu.-; within this range, high photosensitivity can be obtained and the residual potential will be low.

The substrate (1) includes a metal conductor such as brass, copper, 5TLS, and AI, or a conductor thin film coated on the surface of an insulator such as glass and ceramics. This is advantageous in terms of adhesion to the Ga-SiC layer.

Further, the electrophotographic photoreceptor of the present invention has an organic photoconductor layer (3).
It can be set to a negatively charged type or a positively charged type by selecting the material. That is, in the case of a negatively charged electrophotographic photoreceptor, an electron-prone compound is selected for the organic photosemiconductor layer (3);
In the case of a positively charged electrophotographic photoreceptor, an organic optical semiconductor layer (3
) with electron withdrawal) ↑ Compound is selected.

Electron-donating compounds include those with a polymer layer.
These include N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, bireni/-formaldehyde condensation polymers, and low molecular weight products such as oyazadiazole, oxazole, biracillin, triphenylmethane, hydrazone, triarylamine, and N-phenylcarbazole. , stilbene, etc., and these low-molecular substances are
polycarbonate, polyester, methacrylic resin,
It is used dispersed in a binder such as polyamide, acrylic epoxy, polyethylene, phenol, polyurethane, butyral resin, polyvinyl acetate, or urea resin.

Electron-withdrawing compounds include 2.4.7-)linitrofluorenone.

Next, a method for manufacturing the electrophotographic photoreceptor of the present invention will be described.

To form the a-SiC layer, there are thin film forming methods such as glow discharge decomposition method, ion blating method, reactive sputtering method, vacuum evaporation method, and CVD method.

When using the glow discharge decomposition method, Si element-containing gas and C
A film is formed by combining element-containing gases and plasma decomposing the mixed gas. This Si element-containing gas includes SiH4,
SiJi+SiJ*, 5IFI, SiC14, SiHC
h, etc., and gases containing C element include C114, C
d4. There are CJ2+C3H1, etc., and CtHz is particularly desirable in that it can provide high-speed film formation.

The glow discharge decomposition device used in this example will be explained with reference to FIG.

In the figure, SiH4+CJz and H2 are sealed in the first tank (4), the second tank (5), and the third tank (6), respectively, and these gases are in the corresponding 31st! Valve adjustment (7)
, the second regulating valve (8) and the 31st! It is released by opening the regulating valve (9). The flow rate of the released gas is determined by the mass flow controller (10) (11) (12).
controlled by the main pipe (13), each gas is mixed
sent to. Note that (14) and (15) are stop valves.

The gas flowing through the main pipe (13) flows into the reaction tube (16), and a capacitively coupled discharge electric scraper (17) is installed inside this reaction tube (16). A substrate (18) is placed on a substrate support (19), and the substrate support (19) is rotationally driven by a motor (20).
Along with this, the substrate (18) is rotated. Then, the electrode (17) has a power of 50 to 3 Kw and a frequency of 1 to 50 Mtl.
z high frequency power is applied, and the substrate (18) is heated to about 200 to 400°C, preferably about 2
It is heated to a temperature of 00 to 350°C. In addition, a reaction tube (1
6) is connected to a rotary pump (21) and a diffusion pump (22).
orr) is maintained.

A substrate (1
When forming an a-SiC layer on top of 8), the first regulating valve (
7), open the second regulating valve (8) and third regulating valve (9) and
Each gas of iH4, Cdh+Hz is released, and the release amount is controlled by a mass flow controller (10) (11) (1
2), each gas is mixed and sent to the main pipe (13
) into the reaction tube (16). When the interior of the reaction tube is set to predetermined conditions, glow discharge occurs, and an a-SiC film is rapidly formed on the substrate as the gas decomposes.

After forming the a-SiC layer by the thin film forming method described above, an organic optical semiconductor layer is then formed.

The organic optical semiconductor layer is formed by a dip coating method or a coating method, in which the former is immersed in a coating liquid in which a photosensitive material is dispersed in a solvent, and then pulled up at a constant speed, and
This method involves natural drying and heat aging (approximately 150°C, 1 hour).In the latter coating method, a photosensitive material dispersed in a solvent is applied using a coater, and then Perform hot air drying.

〔Example〕

Next, examples of the present invention will be described.

(Example 1) An a-SiC photoconductive layer having a thickness of 0.5 μm was formed using the glow discharge decomposition apparatus shown in FIG. 8 under the film forming conditions shown below.

Gas introduction amount Silla... 200 sec C2112... 50 sccm at the start of film formation, and in order not to reduce the flow rate, it was set to zero at the end of film formation.

lh...270secm Gas pressure...0.60Torr High frequency power...150w Substrate temperature...250℃ The average carbon content of this a-SiC photoconductive layer is XMΔ
When measured by X value of Sil-C, , 0
It was ゜22.

Next, an organic photo-semiconductor layer in which a hydrazone compound is dispersed in polycarbonate is placed on the a-3iC photoconductive layer for 15 minutes.
It was formed to have a thickness of .mu.-, and was used as an electrophotographic photoreceptor.

When the properties of the electrophotographic photoreceptor thus obtained were measured using an electrophotographic property measuring device, it was found that a high surface potential and excellent photosensitivity were obtained.

(Example 2) In manufacturing the electrophotographic photoreceptor of (Example 1), CJ
Setting the z gas flow rate to a constant value of 255CC1+1 and keeping all other film forming conditions the same, thereby forming an aSiC photoconductive layer, and further forming an organic photoconductive layer in the same manner,
This was used as a comparative electrophotographic photoreceptor.

When the surface potential of this electrophotographic photoreceptor was measured, it was found to be about 10x lower than that of the photoreceptor of Example 1.

(Example 3) Next, in forming the a-SiC photoconductive layer of Example 1), the present inventors created a first a-3iCrVJ region in which carbon was gradually reduced from the substrate side and carbon was added in the layer thickness direction. A second a-SiCl1Rff region, which is constant over the period of time, was successively formed. The film forming conditions are as shown in Table 1.

The gas introduction amounts marked in Table 1 are the respective values from the start of film formation to the time of film formation Hiiragi Y.

Furthermore, when the carbon content of each layer region was measured by XMA, the average value was X·0.38 in the first a-SiC layer region, and x−0 in the second a-SiCffi region. , 17.

The electrophotographic photoreceptor thus obtained was also excellent in both surface potential and photosensitivity.

(Example 4) In this example, in manufacturing the electrophotographic photoreceptor of (Example 3), B10. Connect it to a cylinder filled with gas (8211h diluted with hydrogen at a concentration of 40ppn+), and connect it to the first and second a-S at a flow rate of 90sce from the gas cylinder.
It was introduced at the time of forming the iC1ijJ region, and all other manufacturing conditions were the same as in Example 3 to produce an electrophotographic photoreceptor.

The B content of this a-5jC photovoltaic layer was measured by secondary ion mass spectrometry and found to be 15 ppm.

The electrophotographic photoreceptor thus obtained had a photosensitivity increased by 8χ compared to the photoreceptor of Example 3.

〔Effect of the invention〕

As described above, according to the electrophotographic photoreceptor of the present invention, an a-SiC photoconductive layer with varying carbon content in the N thickness direction is formed, and as a result, a high surface potential can be obtained. Ta.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the layer structure of the electrophotographic photoreceptor of the present invention;
Moreover, FIG. 2, FIG. 3, FIG. 4, FIG. 5, FIG. 6, and FIG. 7 are diagrams showing the carbon content, and FIG. 8 is an explanatory diagram of the glow discharge decomposition apparatus. (1)... Conductive substrate (2)... Amorphous silicon carbide 1' light guide i
Layer (3)...Organic optical semiconductor layer Patent applicant (663) Kyocera Corporation Representative Kazuo Anjo Takao Kawamura

Claims (3)

[Claims] (1) In an electrophotographic photoreceptor in which an amorphous silicon carbide photoconductive layer and an organic photoconductive layer are sequentially laminated on a conductive substrate, the amorphous silicon carbide photoconductive layer is gradually applied from the substrate to the surface of the photoreceptor in the layer thickness direction. An electrophotographic photoreceptor characterized in that a layer region having a reduced carbon content is formed. (2) Claim (1) wherein the average carbon content of the amorphous silicon carbide photoconductive layer is within the range of 0.05<x<0.5 as the X value of the composition formula Si_1_-_xC_x.
) The electrophotographic photoreceptor described above. (3) The electrophotographic photoreceptor according to claim 1, wherein the amorphous silicon carbide photoconductive layer has a thickness in the range of 0.05 to 5 μm.