JPH01232353A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a photosensitive body having high photosensitivity, superior performance, and high quality by specifying a compsn. and proportion of elements of a photoconductive layer of a photosensitive body constituted of an a-SiC photoconductive layer and an org. semiconductor layer laminated on an electroconductive substrate. CONSTITUTION:A photosensitive body is formed by laminating an a-SiC photoconductive layer 2 and an org. semiconductor layer 3 on an electroconductive substrate 1. The layer 2 consists of Si element, C element, and H element or halogen element, and values of x and y are regulated to within a range: 0.05<x<0.5 and 0.2<y<0.5, when the compsn. of the layer 2 is expressed by [Si1-xCx]1-yAy (wherein A is H or halogen). If x is <=0.05, photosensitivity of a short wavelength side is not improved. If it is >=0.5, photoconductivity is decreased. If y is <=0.2, dark conductivity increases, and if it is >=0.5, deterioration of adhesion occurs due to increase of internal stress in the layer 2. Thus, a photosensitive body having superior photosensitivity, superior performance, and high quality is obtd.

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 photoconductive layer and an organic photoconductor layer.

[Prior art and its problems]

Photoconductive materials for electrophotographic photoreceptors include Se and 5e-Te.

There are inorganic materials such as 8szS ai, Zno, CdS, and amorphous silicon, and various organic materials. Among them, Se was the first to be put into practical use, and then ZnO,
CdS and amorphous silicon have also been put into practical use. On the other hand,
Among organic materials, PVK was first put to practical use, and later, a functionally separated photoreceptor was proposed in which the functions of charge generation and charge transport were shared between separate materials, and this functionally separated photoreceptor led to the development of organic materials. is developing rapidly.

On the other hand, an electrophotographic photoreceptor in which an organic photoconductive layer is laminated on the above-mentioned inorganic photoconductive layer has also been proposed.

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

Therefore, Japanese Unexamined Patent Application Publication No. 14241/1988 proposes a laminated photoreceptor consisting of an amorphous silicon carbide photoconductive layer and an organic photoconductor layer. The properties of pollution resistance and high light sensitivity were obtained.

According to the electrophotographic photoreceptor in the above publication, the chemical formula is Si1□
C, I+, ((tanshi O<X<1, 0.05
It has a structure in which an amorphous silicon carbide layer represented by y 0.2 and an organic optical semiconductor layer are sequentially laminated.

However, when the present inventors manufactured such an electrophotographic photoreceptor and measured its photosensitivity, it was found that satisfactory characteristics were not yet obtained and further improvement was required.

Therefore, the present invention has been completed in view of the above,
The purpose is to provide an electrophotographic photoreceptor with high photosensitivity.

[Means for Solving the Problems] According to the present invention, an amorphous silicon carbide photoconductive layer (hereinafter amorphous silicon carbide is abbreviated as a-3iC) and an organic photoconductive layer are sequentially laminated on a conductive substrate. In the electrophotographic photoreceptor, the constituent elements of the a-5iC photoconductive layer are Si element, C element, and hydrogen or halogen, hydrogen or halogen is expressed as H element, and the element ratio of the core layer is according to the composition formula ( Si+-XCX), -98,
, X and y are each 0.05
An electrophotographic photoreceptor is provided, characterized in that the values are set within the ranges of < x < o, s , 0.2 < y < 0.5.

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-SiC photoconductive layer (2) and an organic photo-semiconductor layer (3) are sequentially laminated on a conductive substrate (1). The a-3iC photoconductive layer (2) has a function of charge generation, and the other organic photoconductive layer (3) has a function of charge transport.

The present invention is characterized in that when the element ratio of the a-3iC optically exclusive layer (2) is set within the following range, the photosensitivity of this layer (2) itself can be significantly increased. It is.

Compositional formula: C5++-x CX ] ly Ay
(However, A is hydrogen or halogen) 0.05 < x < 0.5, preferably 0.1 < x < 0.40.2 < V
< 0.5, preferably 0.25 < y < 0.45
When the above X value is 0.05 or less, the photosensitivity on the short wavelength side cannot be increased, and when the X value is 0.5 or more, the photoconductivity decreases significantly and the excitation function of photocarriers decreases. .

Furthermore, when the y value is 0.2 or less, the dark conductivity tends to increase, and the photoconductivity tends to decrease, so that the desired photoconductivity cannot be obtained and the y value decreases. 0.5
In the above case, the internal stress of the a-SiC layer increases, and the adhesion with the substrate deteriorates, making it easy to peel off.

Further, the a-5iC photoconductive layer (2) contains hydrogen (previous element and halogen element for dangling bond termination), but among these elements, H element is easily incorporated into the termination portion, This is desirable in that the localized level density in the hand gear is reduced.

The thickness of the a-5iC photoconductive layer (2) is 0.05 to 5 μm
, is preferably set within the range of 0.1 to 3 μm; within this range, high photosensitivity can be obtained and the residual potential will be low.

The substrate (1) includes a metal conductor such as copper, brass, S[IS, AI, etc., or an insulator such as glass or ceramics coated with a conductive thin film on the surface. This is advantageous in terms of adhesion to the surface and the a-5iC 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-donating compound is selected for the organic optical semiconductor layer (3);
In the case of a positively charged electrophotographic photoreceptor, an organic optical semiconductor layer (3
) is selected as an electron-withdrawing compound.

Examples of the electron-donating compounds include high molecular weight compounds such as poly-N-vinyl trihydrazur, polyvinylpyrene, polyvinylanthracene, and formaldehyde condensation polymers of pyrene, and low molecular weight compounds such as oxadiazole, oxazole, and birapurin. , triphenylmethane, hydrazone, triarylamine, N-phenylcarbazole, and stilhen.
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.

Examples of the electron-withdrawing compound include 2.4.7-)linitrofluorene.

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

To form the a-5iC layer, there are thin film forming methods such as glow discharge decomposition method, ion blating method, reactive sputtering method, vacuum evaporation method, and CVO 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 has 5i114
+5i2t16,5j3He+SiF4,5iC14,
5iHC13, etc., and C element-containing gases include C
lI4. Czt14. Cz) I2, C3118, etc., and Czllz 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, the first tank (4), the second tank (5), and the third tank (6) are each sealed with 5i) Ia, CzHz, and H2, and these gases are supplied to the corresponding first regulating valve (7).
), the second regulating valve (8) and the third regulating valve (9) are opened. 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 electrode (17) is installed inside this reaction tube (I6). 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 50W to 3Kw and a frequency of 1 to 50M.
High frequency power of l1z is applied, and the substrate (1 day)
is heated by suitable heating means to a temperature of about 200-400°C, preferably about 200-350°C. In addition, the reaction tube (16) is connected to a rotary pump (21) and a diffusion pump (22), which provide the required vacuum G (gas pressure during discharge 0.1 to 2.0 .0
Torr) is maintained.

Using a glow discharge decomposition device with such a configuration, groups vi,
When forming an a-5iC layer on (1B), open the first regulating valve (7), the second regulating valve (8), and the third regulating valve (9) to form each of SiH, Czll□+H2. release gas,
Mass flow controller (10) (11)
) (12), each gas is mixed and flows into the reaction tube (16) via the main pipe (13). Then, by setting the vacuum inside the reaction tube, the substrate temperature, and the high-frequency power applied to the electrodes to predetermined conditions, a glow discharge occurs, and an a-5iC film is rapidly formed on the substrate as the gas decomposes. .

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

The organic photosemiconductor layer is formed by a dip coating method or a coating method, in which the photosensitive material is immersed in a coating solution in which it is dispersed in a solvent, and then pulled up at a constant speed;
Natural drying and heat aging (about 150°C for about 1 hour)
According to the latter coating method, a photosensitive material dispersed in a solvent is applied using a coater, and then hot air drying is performed.

〔Example〕

Next, examples of the present invention will be described.

(Example 1) Using the glow discharge decomposition apparatus shown in Fig. 2, SiH, gas was supplied at a flow rate of 200 sec, and I(, gas was supplied at 270 sec).
At a flow rate of , and by changing the flow rate of CZ11□ gas,
In addition, the gas pressure was set to 0.6 Torr, and the high frequency power was set to 150 Torr.
W, the substrate temperature was set at 250° C., and an a-SiC film (film thickness of about 1 μ1 m) was formed by glow discharge.

In this way, the carbon content ratio of the a-3iC film was changed, and the amount of carbon in the film was measured by the XMA method.
Further, when the photoconductivity and dark conductivity were measured, the results shown in FIG. 3 were obtained.

In FIG. 3, the horizontal axis represents the carbon content ratio, that is, Si.

xCxOX value, the vertical axis represents conductivity, ○ mark is a plot of photoconductivity for emission wavelength 550 nm (light intensity 50 μW/cmz), * mark is a plot of dark conductivity, and a, b are their respective characteristic curves.

Furthermore, when the hydrogen content of each of the above a-SiCWJs was determined by infrared absorption measurement, the results shown in FIG. 4 were obtained.

In Fig. 4, the horizontal axis is the X value of Si+-xCx, and the vertical axis is the hydrogen content, that is, C3i1-CX] +-y Hy
The symbol ◯ is a plot of the amount of hydrogen bonded to the Si atom, the symbol • is the plot of the amount of hydrogen bonded to the C atom, and c and d are the respective characteristic curves.

As is clear from FIG. 4, it can be seen that the a-5iC films of this example all have y values within the range of 0.3 to 0.4.

Furthermore, as is clear from Fig. 3, if the carbon content ratio y is within the range of 0.2 < y < 0.5, the ratio of photoconductivity to dark conductivity becomes significantly large, resulting in excellent photosensitivity. It can be seen that is obtained.

(Example 2) Next, in this example, S i II and gas are
At a flow rate of ccmO, CzItz gas was introduced at a rate of 20 sec, and 11° gas was introduced at a flow rate of 0 to 101,000 sc, and the high frequency power was set to 50 to 300 W, and the gas pressure was set to 0.3 to 2 Torr. Then, an a-5iC film (film thickness of about 1 μm) was formed by glow discharge.

In this way, various a-5iC films were formed with the carbon content ratio X set to 0.3 and the hydrogen content FJ, y varied, and the photoconductivity and dark conductivity of each film were measured. , the results shown in FIG. 5 were obtained.

In Figure 5, the horizontal axis is the hydrogen content, that is (Si6.7 C0
-3] +-y It, the vertical axis represents the conductivity, and the circle mark indicates the emission wavelength of 550 nm (light intensity: 50 μW/
Fig. 3 is a plot of photoconductivity versus cm''), the * mark is a plot of dark conductivity, and e and f are respective characteristic curves.

As is clear from Figure 5, when the y value exceeds 0.2,
It can be seen that high photoconductivity as well as low dark conductivity are obtained.

In addition, the present inventors (Sio, 7 Co, :+)
a-3iC consisting of the compositions o, i, 5llo, 35
An electrophotographic photoreceptor was fabricated in which a photoconductive layer and an organic photoconductor layer in which a hydrazone compound was dispersed in polycarbonate were sequentially laminated, and its characteristics were evaluated. As a result, a high surface potential and excellent photosensitivity were obtained. Moreover, the residual potential was low.

[Effect of the invention] As described above, according to the electrophotographic photoreceptor of the present invention, a-5
When the amount of carbon in the iC photoconductive layer and the amount of the element for dangling bond termination are set within predetermined ranges, excellent photosensitivity can be obtained, and therefore, this a-SiC photo-slow layer photoconductor By making the layers well-known, a high-performance and high-quality electrophotographic photoreceptor can be provided.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the layer structure of the electrophotographic photoreceptor of the present invention, FIG. 2 is a schematic diagram of a glow discharge decomposition device used in Examples, and FIG. 3 is a line showing the relationship between carbon content ratio and electrical conductivity. 4 is a diagram showing the relationship between carbon content ratio and hydrogen content, and FIG. 5 is a diagram showing the relationship between hydrogen content and electrical conductivity. 1... Conductive substrate 2... Amorphous silicon carbide photoconductive layer 3... Organic optical semiconductor layer Patent applicant (663) Kyocera Corporation Representative Norikata Anjo Takao Kawamura

Claims (1)

[Claims] 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 constituent elements of the amorphous silicon carbide photoconductive layer are Si element, C element, and hydrogen or halogen; , hydrogen or halogen is expressed as element A, and the element ratio of the layer is the composition formula {Si_1_-_xC_x}_1_
An electrophotographic photoreceptor characterized in that, when expressed as -yA_y, x and y are set within the range of 0.05<x0.5 and 0.2<x0.5, respectively.