JPH02146054A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance photosensitivity by successively laminating an a-SiC photoconductive layer and an organic photosemiconductive layer on a conductive substrate, specifying an elementary proportion of the layer, and incorporating a specified amount of an element of group Va of the periodic table. CONSTITUTION:The electrophotographic sensitive body is formed by successively laminating on the conductive substrate 1 the amorphous silicon carbide a-SiC photoconductive layer 2 and the organic photosemiconductive layer 3. The layer 2 is composed of Si, C, and H or halogen elements represented by an elementary composition formula: (Si1-xCx)1-yAy, where A is hydrogen or halogen, and 0.05 < x < 0.5, and 0.2 < y < 0.5, and containing further an element of group Va of the periodic table in an amount of <=100ppm, thus permitting the obtained electrophotographic sensitive body to be high in photosensitivity.

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, 5e-Te,
.

There are inorganic materials such as AszS az+ZnO1CdS 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-TNF was first put into 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. development is progressing rapidly.

On the other hand, an electrophotographic photoreceptor in which an organic photoconductive layer is laminated on an 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, a laminated photoreceptor consisting of a rufous silicon carbide photoconductive layer and an organic optical semiconductor layer has been proposed in JP-A-56-14241 No. υ, and this photoreceptor solves the above problems. The characteristics of non-polluting properties and high photosensitivity were obtained.

According to the electrophotographic photoreceptor of the above publication, the chemical formula 5iXCX
l! , (where 0<x<1.0.05≦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.

Furthermore, the electrophotographic photoreceptor proposed above, as well as an electrophotographic photoreceptor using an organic photosemiconductor layer as a photocarrier generation layer,
In other words, OPC photoreceptors are used for negative charging, and as a result, corona discharge may cause uneven charging, or an increased amount of ozone may be generated, deteriorating the photoreceptor surface, resulting in poor quality of the copied image. The image quality of the photoreceptor itself deteriorates, and the durability of the photoreceptor itself deteriorates.

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

Another object of the present invention is to provide an electrophotographic photoreceptor for positive charging.

Still another object of the present invention is to provide an electrophotographic photoreceptor that maintains excellent electrophotographic properties over a long period of time.

Means for Solving Problem c] According to the present invention, an electronic photoconductive layer in which 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 photographic photoreceptor, the constituent elements of the a-3iC 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 expressed by the composition formula (S! +-x Cx) +-y
When expressed as 8, X and y are each 0.05
< x < 0.5. An electrophotographic photoreceptor is provided.

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

In the present invention, the element ratio of the a-SiC photoconductive layer (2) and the content of Group Va elements of the periodic table (hereinafter abbreviated as Group Va elements) are set within the following ranges, and the nuclear layer ( When an electron-withdrawing organic optical semiconductor layer (3) is laminated on 2),
It is characterized by being able to be positively charged and also being able to significantly increase photosensitivity.

Compositional formula: (Si+-x Cx) +-AV (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
Va group element content i1: 1100 pp or less, preferably 0.
1 to 50 ppm If the above X value is 0.05 or less, the photosensitivity on the short wavelength side will not be increased, and if the X value is 0.5 or more, the photoconductivity will be extremely low and the excitation of photocarriers Function deteriorates.

In addition, when the ν 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 decreases, making it easy to peel off.

Regarding the Va group element content, if it exceeds 100 pI11, the dark conductivity becomes significantly large, and the ratio of the photoconductivity to the dark conductivity becomes small, making it impossible to obtain the desired photosensitivity.

When the Va group element is contained in the a-5iC photoconductive layer (2), the doping distribution may be either uniform or non-uniform over the layer thickness direction. In the case of non-uniform doping, there may be a layer region in which the Va group element is not contained in a part of this layer (2). The average content of Va group elements in the entire a-3iC layer, which is composed of both the a-SiC layer region and the non-containing a-SiC layer region, must be 100 p4 or less.

These Va group elements include N, P, As, Sb, Bi
However, P is desirable because it has excellent covalent bonding properties and can quickly change semiconductor properties, and also provides excellent charging ability and photosensitivity.

Further, the a-5iC photoconductive layer (2) contains hydrogen (11).
Elements and halogen elements are contained for dangling bond termination, but among these elements, l[element is easily incorporated into the termination, which reduces the localized level density in the punt gap. It is desirable in that sense.

The thickness of the a-5iC photoconductive layer (2) is 0.05 to 5 μm,
It is preferable to set it within the range of 0.1 to 3 μm, and 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, 5TLS, At, or an insulator such as glass or ceramics coated with a conductive thin film on the surface. -3 It is advantageous in terms of adhesion to the iC layer.

Examples of the electron-absorbing compound used in the organic optical semiconductor layer (3) include 2.4.7-1-linitrofluorene.

, the residual potential becomes lower.

Thus, in the laminated photoreceptor of the present invention, the photosensitivity is increased by the a-3iC photoconductive layer (2) having a predetermined composition,
Furthermore, the combination with the organic optical semiconductor N(3) makes it positively charged.

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,
5izlL, 5iJa, SiF4,5iC14,5il
lCI3, etc., and the C element-containing gas is CHt.
, CJt, Czl12+C:IHe, etc., and C and H2 are particularly desirable in that they 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), second tank (5), third tank (6), and fourth tank (7) are filled with SiH4 and C, respectively.
ztlz, PIIff, (PHz has been diluted with hydrogen at a concentration of 30 pprrl) and H2 are sealed, and these gases are supplied to the corresponding first regulating valve (8), second regulating valve (9), and third regulating valve ( 10) and the fourth regulator valve (11) are opened. The flow rate of the released gas is controlled by a mass flow controller (12) (13), respectively.
(14) and (15), each gas is mixed and sent to the main pipe (16). Furthermore, (17) (18
) is a stop valve.

The gas flowing through the main pipe (16) flows into the reaction tube (19), and a capacitively coupled discharge electrode (20) is installed inside this reaction tube (19), and a cylindrical film-forming electrode (20) is installed inside the reaction tube (19). A substrate (21) is placed on a substrate support (22), the substrate support (22) is rotationally driven by a motor (23),
Along with this, the substrate (21) is rotated. Then, the electrode (20) has a power of 50W to 3Kw and a frequency of 1 to 50M.
IIz high frequency power is applied, and the substrate (21)
is heated by suitable heating means to a temperature of about 200-400°C, preferably about 200-350°C. In addition, the reaction tube (19) is connected to a rotary pump (24) and a diffusion pump (25), which provide the necessary reduced pressure B (gas pressure during discharge 0.1 to 2) during film formation by glow discharge. .0
Torr) is maintained.

The substrate (2
When forming the a-5iC layer on 1), the first regulating valve (
8), second regulating valve (9), third regulating valve (10) and fourth regulating valve
Open the adjustment valve (11) and set S iHa + Cz ”□,
PII+ and Hz gases are released and the release amount is controlled by a mass flow controller (12) (13) (14)
(15), each gas is mixed and sent to the main pipe (
16) into the reaction tube (19). and,
When the reduced pressure inside the reaction tube, substrate temperature, and high-frequency power applied to the electrodes are set to predetermined conditions, glow discharge occurs, and as the gas decomposes, an a-5iC film containing P element is rapidly formed on the substrate. be done.

After forming the a-5iC layer 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. According to the latter coating method, a photosensitive material dispersed in a solvent is applied using a coater, and then dried with hot air. I do.

〔Example〕

Next, examples of the present invention will be described.

(Example 1) Using the glow discharge decomposition device shown in Fig. 2, 5il14 gas was mixed with 1 hydrogen dilution circle (3 gas was mixed with 9
The flow rate of H2 gas was 270 seconds, and the flow rate of C112 gas was changed at a flow rate of 0, sccm, and the gas pressure was Q, 6 Torr, and the high frequency power was 150 W.
The substrate temperature was set at 250℃, and a-
A 3iC film (film thickness approximately 1 μm) was formed.

In this way, the carbon content ratio of the a-5iC 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 addition, when the P element content contained in each a-3iC film was measured using a secondary ion mass spectrometer, it was found to be approximately 10 ppm in each case.

In Figure 3, the horizontal axis represents the carbon content ratio, that is, the X value of 5iXCX, the vertical axis represents the electrical conductivity, and the circle indicates the emission wavelength
It is a plot of photoconductivity for light of 50r++n (light intensity 50 μ-/am”), the * mark is a plot of dark conductivity, and a and b are respective characteristic curves.

When the hydrogen content of each of the above a-5iC films was determined by infrared absorption measurement, the results shown in FIG. 4 were obtained.

In Fig. 4, the horizontal axis is the Si+-x CxOX value, and the vertical axis is the hydrogen content, i.e. (Si+-x CX) ly
These are the LOy values, the ◯ mark is a plot of the amount of hydrogen bonded to the Si atom, the * mark 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-3iC 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 X is within the range of 0.2 < It turns out that is obtained.

(Example 2) Next, in this example, SiH4 gas is used at a flow rate of 200 sec, C211□ gas is used at a flow rate of 20 sec, hydrogen dilution P1 (3 gases are used at a flow rate of 90 sccm, and 11□ gas is used at a flow rate of O~101000 sc. and high frequency power of 50 to 300W.

The gas pressure was set at 0.3 to 1.2 Torr, and an a-SiC film (film thickness of approximately 1 μm) was formed by glow discharge.

In this way, various a-3iC films were formed with the carbon content ratio X set to 0.3 and the hydrogen content ff1y varied, and the photoconductivity and dark conductivity of each film were measured. The results shown in Figure 5 were obtained. In addition, the P element content of each a-SiC film is approximately 10ρpn.
In Figure 5, the horizontal one is the hydrogen content, that is, [Sio, + C
8, 3] 1□ 11. The vertical axis represents the conductivity, and the O mark indicates the emission wavelength of 550 nm (light intensity: 50 p W/
3.cmz) is a plot of photoconductivity for light, 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.

(Example 3) In this example, S i 114 gas is
C, H2 gas at a flow rate of 20 sec, hydrogen diluted PLh gas (iWt degree 0.2χ or 30 ppm) at a flow rate of 5 to 500 sec, and H2 gas at a flow rate of 200 sec.
Then, the high frequency power was set to 150 m, the gas pressure was set to 0.6 Torr, and a P element-containing a-3jC film (film thickness of about 1 μm) was formed by glow discharge.

Thus, the carbon content ratio The results shown in FIG. 6 were obtained.

In this example, BzHi gas was introduced in place of the above-mentioned circle 13 gas, and various a-3iC films with varying eight element contents were also formed, and the measurement results thereof were also obtained.

In the figure, the horizontal axis represents the P element content (or 8 element content), the vertical axis represents the electrical conductivity, and the circle indicates the emission wavelength of 550 nm.
It is a plot of photoconductivity for light with a light intensity of 50 μW/cm2, and the mark is a plot of dark conductivity, and
g+h are the respective characteristic curves.

As is clear from FIG. 6, it can be seen that when the P element is contained within a range of 1100 pp or less, the ratio of photoconductivity to dark conductivity becomes sufficiently large.

Incidentally, any a-3iC film in this example has a carbon content ratio ×
and hydrogen content y are respectively x = 0.30. y・0.
It is 35.

In addition, the present inventors have found that [S
io,? Co, i) o, 6sllo, 35
an a-3iC photoconductive layer having the composition of 2.4.7 and
- When we fabricated an electrophotographic photoreceptor in which organic photoconductor layers of trinitrofluorene were sequentially laminated and evaluated its characteristics by positive charging, we found that it had a high surface potential, excellent photosensitivity, and a low residual potential. It became.

〔Effect of the invention〕

As mentioned above, according to the electrophotographic photoreceptor of the present invention, a-3
When the amount of carbon, the amount of the dangling bond termination element, and the Group Va element content of the iC photoconductive layer are set within predetermined ranges, excellent photosensitivity can be obtained, and therefore, this a-SiC photoconductive layer A high performance and high quality electrophotographic photoreceptor can be provided by combining the organic photoconductor layer and the organic photoconductor layer.

In addition, the electrophotographic photoreceptor of the present invention is used for positive charging, which prevents uneven charging due to corona discharge and generates less ozone, resulting in high image quality. images could be provided for a long period of time.

[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. Figure 4 is a diagram showing the relationship between carbon content ratio and hydrogen content, Figure 5 is a diagram showing the relationship between hydrogen content and electrical conductivity, and Figure 6 is a diagram showing the relationship between hydrogen content and electrical conductivity. FIG. 2 is a diagram showing the relationship between Va group element content and electrical conductivity. 1... Conductive substrate 2... Amorphous silicon carbide photoconductive layer/organic optical semiconductor layer 3 Patent applicant (663) Kyocera Corporation a*! j Anjo Kinjudo Takao Kawamura

Claims (6)

[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 constituent elements of the amorphous silicon carbide photoconductive layer are Si element, C element, hydrogen, or halogen. Therefore, hydrogen or halogen is expressed as element A, and the element ratio of the layer is given by the composition formula [Si_1_-_xC_x]_1
When expressed as ____yA_y, x and y are each 0
．． 05<x<0.5, 0.2<y<0.5, and further contains 10 elements of group Va of the periodic table in the photoconductive layer.
An electrophotographic photoreceptor characterized in that the content is within a range of 0 ppm or less. (2) The electrophotographic photoreceptor according to claim (1), which is a positively charged type. (3) The electrophotographic photoreceptor according to claim (1), wherein the Group Va element of the periodic table is P. (4) The electrophotographic photoreceptor according to claim (1), wherein the organic optical semiconductor layer comprises an electron-withdrawing compound. (5) The electrophotographic photoreceptor according to claim 1, wherein the amorphous silicon carbide photoconductive layer has a thickness within the range of 0.05 to 5 μm. (6) The electrophotographic photoreceptor according to claim (1), wherein the thickness of the organic optical semiconductor layer is within the range of 10 to 50 μm.