JPH0789233B2 - Electrophotographic photoreceptor - Google Patents

Description

The present invention relates to an electrophotographic photosensitive member comprising a photoconductive amorphous silicon carbide layer, and more particularly to an electrophotographic photosensitive member which can be charged negatively.

[Prior art and its problems]

In recent years, the progress of electrophotographic photoconductors has been remarkable, and various properties have been required for the photoconductor itself with the development of copying machines, printers, etc. equipped with the photoconductor. In response to this requirement, the amorphous silicon layer is drawing attention because it is excellent in heat resistance, abrasion resistance, pollution-free property, photosensitivity and the like.

However, an amorphous silicon (hereinafter abbreviated as a-Si) layer can obtain a dark resistivity of about 10 ⁹ Ω · cm only if it is not doped with an impurity element, which is used for an electrophotographic photoreceptor. In this case, it is necessary to increase the charge retention ability by setting the dark resistivity to 10 ¹² Ω · cm or more. Therefore, it is possible to dope a small amount of elements such as oxygen and nitrogen to increase the resistance, but on the other hand, there is a problem that the photoconductivity is lowered. In addition, high resistance can be expected even if boron is added, but it is not possible to obtain a sufficiently satisfactory dark resistivity and
Only about ¹¹ Ω · cm.

On the other hand, along with the development of the above-mentioned doping agents, there has been proposed a laminated-type photoconductor in which another non-photoconductive layer is laminated on the a-Si photoconductive layer.

For example, FIG. 2 shows this laminated type photoreceptor, which is a substrate (1).
A carrier injection blocking layer (2), an a-Si photoconductive layer (3), and a surface protection layer (4) are sequentially laminated on the above.

According to this laminated layer photoreceptor, the carrier injection blocking layer (2)
Is for preventing carrier injection from the substrate (1), and the surface protective layer (4) is for protecting the a-Si photoconductive layer (3) to improve moisture resistance and the like, but both layers (2)
In both (4) and (4), the purpose is to increase the dark resistivity of the photoconductor to improve the charging ability, and therefore it is not necessary to make these layers photoconductive.

As described above, the conventionally known a-Si electrophotographic photosensitive member has a great feature in that the photocarrier generation layer is formed by the a-Si photoconductive layer, and thus it is excellent in heat resistance, durability and photosensitivity characteristics. On the other hand, on the other hand, the dark resistivity is insufficient, so that the dark resistivity is increased by using a doping agent or by using a laminated type photoreceptor. That is, the carrier injection blocking layer (2) and the surface protective layer (4) formed on the laminated type photoreceptor complement the defects of the a-Si photoconductive layer itself. ) Can be said to be a layer that can be substantially distinguished.

In view of the above circumstances, the present inventors have already found that amorphous silicon carbide (hereinafter abbreviated as a-SiC) has photoconductivity and easily has a dark resistivity of 10 ¹³ Ω · cm or more regardless of the presence or absence of a doping agent. Furthermore, it was found that an electrophotographic photosensitive member which can be charged to a negative polarity can be obtained by selecting a doping agent.

The reason why the a-SiC layer can be used as an electrophotographic photosensitive member is that the layer has a large carrier mobility and further 10 ⁻¹³ (Ω · c).
This is because the dark conductivity is m) ^-1 or less and a large charging ability is obtained.

However, even with an a-SiC electrophotographic photosensitive member having such a large carrier mobility, further excellent electrophotographic characteristics are desired as the development of the device for mounting the photosensitive member progresses, For example, if the photosensitivity characteristics are not sufficiently satisfactory for the intended use, image fog or residual potential increase may occur, and improvements in these characteristics are desired.

[Object of the Invention]

Therefore, the present invention has been devised in view of the above, and its purpose is to substantially eliminate the need for a surface protective layer and a carrier injection blocking layer, and to form photoconductive a-SiC over all layers, and An object of the present invention is to provide an electrophotographic photosensitive member which has improved photosensitivity characteristics and required electrophotographic characteristics.

Another object of the present invention is to provide an electrophotographic photosensitive member that can be negatively charged.

[Means for solving problems]

According to the invention, 5 to 50 atomic% carbon and 5 on the substrate
To 50 atomic% of hydrogen or halogen element, 5 × 10 ^{-5 to} 1 atomic% of oxygen and 10,000 ppm or less (excluding 0) of the periodic table group Va element, and the dark resistivity is 10 ¹³ Ω -It is formed by forming a photoconductive amorphous silicon carbide layer having a thickness of at least cm and 1,000 times or more as compared with the bright resistivity, the amorphous silicon carbide layer being a first layer region arranged from the substrate side, Second layer area and third
And the third layer region contains more carbon than the second layer region, and the first layer region contains more Va group elements of the periodic table than the second layer region. A negatively chargeable electrophotographic photoreceptor is provided.

Hereinafter, the present invention will be described in detail.

The electrophotographic photoreceptor of the present invention is characterized in that the photoconductive a-SiC layer contains oxygen within a predetermined range, and the photoconductive a-SiC layer contains a Va group element. It has already been proposed by the present inventors that it can be incorporated into a photoreceptor charged with a negative polarity.

That is, according to FIG. 1, a photoconductive a-SiC layer (5) is formed on a conductive substrate (1) by, for example, a glow discharge decomposition method, and carbon and Va are distributed in the layer thickness direction. The group elements are contained in the same content ratio. As a result, it was found that the dark resistivity becomes 10 ¹³ Ωcm or more and 1000 times or more as compared with the bright resistivity, and as will be apparent from the examples described later based on this finding, only this single composition layer is formed. It was an unexpected result that it could be a sufficiently practical a-SiC photoreceptor.

Further, when the inventors of the present invention charge the a-SiC photoreceptor positively or negatively and compare the charging performances of the two,
If the Va group element is doped in the —SiC layer (5) in the range of 0 to 10,000 ppm, preferably 1 to 1000 ppm, the negative polarity can be advantageously increased.

The fact that the doping with the Va group element facilitates the negative charge is not yet clarified and cannot be left out of the speculation, but it is sufficient for the a-SiC layer to hold a negative charge. It is considered that this is because it has a high resistivity, is excellent in the effect of preventing the injection of positive charges from the substrate, and is also excellent in charge mobility with respect to negative charges.

Further, there are N, P, As, Sb and Bi as the Va group element. Among them, P is desirable because it has excellent covalent bond and can sensitively change semiconductor characteristics.

Regarding the point that the a-SiC layer of the present invention has photoconductivity, amorphous silicon and carbon are used as indispensable constituent elements, and hydrogen element (H) and halogen are used to terminate the dangling bond. It is considered that photoconductivity is caused by containing the element within the required range. The present inventors conducted an experiment to confirm the presence or absence of photoconductivity by changing the carbon content ratio in various ways.
Carbon may be contained in the SiC layer (5) in the range of 1 to 90 atom%, preferably 5 to 50 atom%, or the carbon content may be varied in the layer thickness direction within this range. Good.

Further, the content of hydrogen element (H) or halogen element is 5 to
50 atom%, preferably 5 to 40 atom%, optimally 10 to 30
The atomic% is good, and H element is usually used. This H
Since the element is easily taken into the terminal portion of the tungling bond, the localized level density in the band gap is reduced, and thus excellent semiconductor characteristics can be obtained.

Further, a part of the H element may be replaced with a halogen element, whereby the localized level density of the a-SiC layer can be lowered and photoconductivity and heat resistance (temperature characteristic) can be improved.
The substitution ratio is 0.01 out of all elements for dangling bond termination.
It is preferably 50 to 50 atomic%, preferably 1 to 30 atomic%. Also,
Halogen elements include F, Cl, Br, I, At, etc., but among them, when F is used, the bond between atoms becomes large due to its large electronegativity, which makes it excellent in thermal stability. desirable.

The present invention is characterized in that the photoconductive a-SiC layer as described above contains 5 × 10 ^{−5 to} 1 atom% of oxygen,
Within this range, improvement in properties can be expected over the electrophotographic properties in general, but it was found that the photosensitivity properties are particularly remarkable.

That is, oxygen is contained in the a-SiC layer at 5 × 10 ^{−5 to} 1 atom%, preferably 5 × 10 ^{−5 to} 0.1 atom%, and most preferably 5 × 10 ^{−4 to}
When it is contained within the range of 0.1 atom%, the photosensitivity is improved, which makes it possible to apply the device equipped with this photoconductor to a wider range of applications, and of course, lower the photosensitivity. This solves the problem of image fogging and residual electric potential that are high.

Although the present inventors have not sufficiently clarified the points that can be solved in this way, it is considered that the acidity is the element for terminating the dangling bond described above.

When oxygen is contained in the photoconductive a-SiC layer, oxygen gas (O ₂ ), CO, CO ₂ , NO, N ₂ O, NO ₂ or the like is contained in the raw material gas of various thin film forming methods. The gas may be contained, or if it is contained in the film within the above range, it may be unavoidably contained as an impurity.

The thickness of the photoconductive a-SiC layer (5) as described above may be at least 5 μm or more, which allows the surface potential to be −
The upper limit is appropriately selected within the range of 200 V or more and the resolution of the image and the image deletion do not occur. According to the experiments of the present inventors, it is 5 to 100 μm, preferably 10 to 50 μm.
It may be set within the range of m.

Further, the dark decay curve and the light decay curve of the a-SiC layer were obtained, and it was confirmed that the a-SiC layer had a high surface potential, excellent photosensitivity characteristics, and a small residual potential.

Thus, a photoconductive a-SiC of a single composition is formed in the layer thickness direction.
An electrophotographic photosensitive member is provided in which the layers alone are sufficiently practical.

Therefore, the inventors of the present invention have made further intensive studies based on the above results, and by forming various layer regions inside the layer of this single composition, the electrophotographic characteristics can be further improved.

That is, in the electrophotographic photosensitive member of the present invention, the content ratio of the constituent element carbon or Va group element is changed over the layer thickness direction, thereby generating a plurality of layer regions, and the number of the layer regions is increased. Correspondingly, electrophotographic photoreceptors of the following first to fourth aspects are obtained.

In the following embodiments according to the present invention, any of the layer regions formed in the photoconductive a-SiC layer has a photocarrier generation function, whereby 5 × 10 ⁻⁵ enzyme is also added to the layer region.
To 1 atom%, preferably 5 × 10 ^{−5 to} 0.1 atom%, optimally 5 × 10 ^{−4 to} 0.1 atom%, and as a result, the photosensitivity is remarkably improved. To do.

Hereinafter, various aspects of the present invention will be described in detail.

First Aspect According to the first aspect, there is provided an electrophotographic photoreceptor having a photoconductive a-SiC layer formed on a substrate, wherein the a-SiC layer is at least a first layer region and a second layer. Region, the first layer region is arranged closer to the substrate than the second layer region, and contains a larger amount of Va group element than the second layer region. An electrophotographic photosensitive member is provided.

That is, according to this first aspect, the group Va element is contained in the photoconductive a-SiC layer having the single composition shown in FIG.
At least the first layer region and the second layer region are generated by changing the content ratio, and this aspect will be described with reference to FIGS. 3 to 9.

In FIG. 3, a photoconductive a-SiC layer in which a first layer region (6) and a second layer region (7) are sequentially formed on a conductive substrate (1) and both layer regions are integrated. It is important that the first layer region (6) is composed of (5a) and that the first layer region (6) contains more Va group element than the second layer region (7).

The second layer region (7) has a Va group element content of 0 to 10,000.
The amount is appropriately determined within the range of ppm, preferably within the range of 0 to 1,000 ppm, whereby negative charge is obtained and required electrophotographic characteristics such as surface potential and photosensitivity are obtained.
And, the first group containing more Va group elements than this layer region
Forming the layer region (6) of the photoconductive a-SiC layer (5a)
The conductivity increases in the substrate side region of the substrate, which prevents the injection of carriers from the substrate side and causes the photo carriers generated in the entire region of the a-SiC layer to smoothly flow to the substrate, resulting in the surface potential. Is increased and the photosensitivity characteristics are improved.

According to this first aspect, the carbon content can be adjusted as shown in FIGS.
It may be set as shown in the figure. In these figures,
The horizontal axis represents the layer thickness from the substrate to the photoreceptor surface, and the vertical axis represents the carbon content. In addition, on this horizontal axis (6),
The respective ranges shown in (7) represent the first layer region and the second layer region.

That is, FIG. 4 shows that the carbon content ratio is constant over the entire layer, or FIG. 5 shows that the carbon content is reduced in the first layer region, while FIG. Indicates that the first layer region contains a larger amount of carbon than the second layer region, whereby the surface potential is further increased and the photosensitivity characteristics are improved. Also, FIGS.
As shown in the figure, when the carbon content is gradually changed in the layer thickness direction, the surface potential and photosensitivity are further increased and the residual potential is reduced.

Second Aspect According to the second aspect, there is provided an electrophotographic photoreceptor having a photoconductive a-SiC layer formed on a substrate, wherein the a-SiC layer is at least a first layer region and a second layer. An area and a third layer area, the first layer area is arranged on the substrate side of the second layer area, the second layer area is arranged on the substrate side of the third layer area, and the third layer area is The second layer region contains more carbon than the second layer region, the second layer region contains 0 to 10,000 ppm of a Va group element, and the first layer region is more than the second layer region. Provided is a negatively chargeable electrophotographic photoreceptor, which is characterized by containing a large amount of Va group elements.

That is, according to this second aspect, as shown in FIG. 10, a third layer is formed on the second layer region (7) shown in the first aspect.
Layer region (8) of the third layer region (8) is formed, the carbon content of the third layer region (8) is higher than that of the second layer region (7), and
The layer region (6), the second layer region (7) and the third layer region (8) were substantially integrated into a photoconductive a-SiC layer (5b).

When this third layer region (8) is formed, the a-SiC layer (5
The dark resistivity on the surface side of b) becomes large, and the surface potential of the photoconductor is remarkably improved accordingly.

That is, the third layer region (8) is the photoconductive a-SiC layer (5b).
Is formed to increase the resistance of the surface side of the
This is completely distinguishable from the conventionally known surface protective layer (4) described in the drawing. Further, according to the function-separated type photoreceptor having the photocarrier generation layer and the carrier transport layer, the carrier transport layer has a high resistance of 10 ¹³ Ω · cm or more, but this layer has a particularly large photoconductivity. It is not required and is usually only set to a photoconductivity of less than 1000 times the photoconductivity to dark conductivity. On the other hand, the third layer region (8) has photoconductivity of 1000 times or more, and can be sufficiently distinguished from the carrier transport layer.

The layer thickness of the third layer region (8) is preferably 1 time or less, preferably 1/2 time or less, optimally 1/4 time or less, as compared with the second layer region (7). It can be said that it is desirable because the surface potential is remarkably improved, the photosensitivity is excellent, and the residual potential is small.

According to this second aspect, the carbon content distribution of the photoconductive a-SiC layer (5b) is as shown in FIGS. 11 to 16, and the horizontal axis represents the layer thickness from the substrate to the surface of the photoconductor. The vertical axis represents the carbon content. In addition, on this horizontal axis, (6)
The respective ranges shown in (7) and (8) represent the first layer region, the second layer region, and the third layer region.

According to FIG. 12, FIG. 14, FIG. 15 and FIG. 16, the content of carbon is gradually changed over the layer thickness direction, whereby
The surface potential is improved, the photosensitivity is excellent, and the residual potential is reduced.

Third Aspect According to the third aspect, there is provided an electrophotographic photoreceptor having a photoconductive a-SiC layer formed on a substrate, wherein the a-SiC layer is at least a first layer region and a second layer. Regions, a third layer region, and a fourth layer region are sequentially provided from the substrate side toward the photoreceptor surface, and the third layer region is the third layer region in comparison with the second layer region. Of carbon, the second layer region contains 0 to 10,000 ppm of a Va group element, and the first layer region has more Va than the second layer region. Provided is a negatively chargeable electrophotographic photoreceptor, which is characterized by containing a large amount of group elements.

That is, according to the third mode, as shown in FIG. 17, a fourth layer region (9) is further formed on the third layer region (8) shown in the second mode, The fourth layer region (9) is richer in carbon than the third layer region (8), and the first
The layer region (6) to the fourth layer region (9) were substantially integrated into a photoconductive a-SiC layer (5c).

Compared to the third layer region (8), the fourth layer region (9) contains a larger amount of carbon to increase the resistance, and thus the charging ability can be increased and the surface potential can be improved. result,
A photoreceptor having a high withstand voltage and a long life can be obtained.

Furthermore, according to the third aspect, the carbon content distribution of the photoconductive a-SiC layer (5c) is as shown in FIGS. 18 to 21, and the horizontal axis represents the layer thickness from the substrate to the surface of the photoreceptor. The vertical axis represents the carbon content. In addition, on this horizontal axis, (6)
The respective ranges shown in (7), (8) and (9) represent the first layer region, the second layer region, the third layer region and the fourth layer region.

According to FIG. 19 and FIG. 21, the carbon content is gradually changed over the layer thickness direction, which improves the surface potential and the photosensitivity and reduces the residual potential.

Fourth Aspect According to a fourth aspect, there is provided an electrophotographic photoreceptor in which a photoconductive a-SiC layer and an a-SiC surface protective layer are sequentially formed on a substrate, wherein the photoconductive a-SiC layer is At least a first layer region, a second layer region and a third layer region are provided, the first layer region is closer to the substrate than the second layer region, and the second layer region is the third layer region.
Are arranged on the substrate side of the layer region, and the third layer region contains more carbon than the second layer region, and the second layer region contains 0 to 10,000 ppm of a Va group element. In addition, the first layer region contains a larger amount of Va group element than the second layer region, thereby providing a negatively chargeable electrophotographic photoreceptor.

That is, according to the fourth aspect, as shown in FIG. 22, a- is further formed on the third layer region (8) shown in the second aspect.
The SiC surface protective layer (10) is formed.
The iC surface protective layer (10) is formed for overcoating and protecting the surface of the photoconductive a-SiC layer (5b).

The a-SiC surface protective layer (10) is the same as the photoconductive a-SiC layer (5b) in that it is made of a-SiC, but it has a high carbon content to provide high hardness, and thus the surface protection is achieved. Bring about action.

The a-SiC surface protective layer (10) can be made photoconductive or non-photoconductive by changing the composition ratio of its constituent elements,
Increasing the carbon content tends to result in non-photoconductive properties, which results in high hardness characteristics and high hardness a-SiC.
It becomes a surface protection layer.

Further, according to the fourth aspect, the carbon content distribution is shown in FIG.
As shown in FIG. 24, the horizontal axis represents the layer thickness from the substrate to the photoreceptor surface, and the vertical axis represents the carbon content. In addition, on the abscissa, respective ranges (6), (7), (8), and (10) represent the first layer region, the second layer region, the third layer region, and the a-SiC surface protective layer. ing.

Thus, according to the first to fourth aspects, an electrophotographic photoreceptor having significantly higher performance than the single-composition a-SiC photoreceptor shown in FIG. 1 is provided.

Further, according to the present invention, the a-SiC layer having a single composition and the a-SiC layers of the first to third aspects are all photoconductive a.
-SiC layer, which provides sufficiently practical electrophotographic properties, a conventionally known surface protective layer may be formed on the surface of these a-SiC layers.

As the surface protective layer, various materials can be used as long as they have high insulation properties, high corrosion resistance and high hardness characteristics, such as organic materials such as polyimide resin, a-SiC and Si.
_{O 2, SiO, Al 2 O} 3, SiC, Si 3 N 4, a-Si, a-Si: H, a-Si: F, a-S
An inorganic material such as iC: H, a-SiC: F can be used.

Next, a method for producing the electrophotographic photosensitive member of the present invention will be described.

In forming the a-SiC layer according to the present invention, a thin film forming technique such as a glow discharge decomposition method, an ion plating method, a reactive sputtering method, a vacuum vapor deposition method, a CVD method can be used, and is also used. Raw material is solid,
Either liquid or gas may be used. For example, SiH ₄ , Si ₂ H ₆ , and Si ₃ H ₈ are used as gas raw materials for the glow discharge decomposition method.
There are C-based gases such as Si-based gas, CH ₄ , C ₂ H ₂ , C ₂ H ₄ , C ₂ H ₆ , and C ₃ H ₈ , and He gas, H ₂ gas, etc. may be used as a carrier gas. .

In producing the electrophotographic photosensitive member of the present invention, when an a-SiC layer is formed from a mixed gas of a silicon (Si) -containing gas and an acetylene (C ₂ H ₂ ) gas by glow discharge decomposition, a significantly large high-speed formation is achieved. It is desirable in that the film property can be achieved. According to experiments conducted by the present inventors repeatedly, this Si
Although various Si-based gases described above can be used as the containing gas, for example, when using SiH ₄ gas and C ₂ H ₂ gas,
A film formation rate of 5 to 20 μm / hour was obtained. Because of SiH ₄ gas
When an a-SiC film is formed using CH ₄ gas, the film formation rate is about 0.3 to 1 μm / hour.

Next, a capacitively coupled glow discharge decomposition apparatus used in the embodiment of the present invention will be described with reference to FIG.

In the figure, the 1st, 2nd, 3rd, 4th, 5th, 6th tanks (11) (12)
(13) (14) (15) (16) have SiH ₄ , C ₂ H ₂ , and
PH ₃ (containing 0.2% when diluted with H ₂ gas), PH ₃ (33p when diluted with H ₂ gas)
pm), H ₂ and NO gas are sealed, and H ₂ is also used as a carrier gas. These gases are the corresponding
1, 2nd, 3rd, 4th, 5th, 6th adjusting valves (17) (18) (19) (2
It is released by opening 0) (21) (22), and its flow rate is controlled by the mass flow controllers (23) (24) (25) (2
6) Controlled by (27) (28), the gas from the 1st, 2nd, 3rd, 4th and 5th tanks (11) (12) (13) (14) (15) is the first main pipe ( 29), NO gas from the sixth tank (16) is sent to the second main pipe (30). Incidentally, (31) and (32) are stop valves. The gas flowing through the first main pipe (29) and the second main pipe (30) is sent to the reaction pipe (33), and the capacitive coupling type discharge electrode (34) is installed inside the reaction pipe (33). And the high frequency power applied to it is 50W to 3kW
However, the proper frequency is 1 MHz to 50 MHz. Inside the reaction tube (33), a cylindrical film forming substrate (35) made of aluminum is placed on the sample holder (36),
The holder (36) is driven to rotate by a motor (37), and the substrate (35) is heated to about 200 to 400 ° C, preferably about 200 to 350 ° C by a suitable heating means.
Is uniformly heated to the temperature of. Further, the inside of the reaction tube (33) is in a high vacuum state (discharge voltage 0.1 to 2.
It is connected to the rotary pump (38) and the diffusion pump (39) by requiring 0 Torr.

In the glow discharge decomposition apparatus configured as described above,
For example, an a-SiC film (containing oxygen and P) is used as a substrate (35).
If it is formed in the first, second, third, fifth adjustment valve (17)
Open (18), (19), and (21) to see SiH ₄ , C ₂ H ₂ , and
The PH ₃ and H ₂ gases are released, and the sixth adjusting valve (22) is opened to release NO gas. The release amount is controlled by the mass flow controller (23) (24) (25) (27) (28)
The mixed gas of H ₄ , C ₂ H ₂ , PH ₃ and H ₂ is flown into the reaction tube (33) through the first main pipe (29) and the NO gas is passed through the second main pipe (30). Then, the inside of the reaction tube (33) is 0.1 to
Glow discharge in conjunction with the vacuum state of about 2.0 Torr, the substrate temperature of 200 to 400 ° C, the high frequency power of the capacitive discharge electrode (34) set to 50 W to 3 kW, or the frequency of 1 MHz to 50 MHz. Occurs, and the gas is decomposed to form an a-SiC film containing oxygen and P on the substrate at a high speed.

〔Example〕

 Next, examples of the present invention will be described in detail.

(Example 1) In this example, a photoconductive a-SiC layer having a uniform single composition along the layer thickness direction was formed on an aluminum film-forming substrate (35), and electrophotographic characteristics were measured.

That is, using the capacitively coupled glow discharge decomposition apparatus shown in FIG. 25, SiH ₄ gas from the first tank (11) at a flow rate of 150 sccm and C ₂ H ₂ gas from the second tank (12) at a flow rate of 10 sccm. so,
PH ₃ gas from the 4th tank (14) at a flow rate of 100 sccm
The H ₂ gas was discharged from the tank (15) at a flow rate of 100 sccm, and the NO gas was discharged from the sixth tank (16) at a flow rate of 0.1 sccm to produce an a-SiC film with a thickness of about 30 μm based on the glow discharge decomposition method. did. As manufacturing conditions, the substrate temperature was 300 ° C and the gas pressure was
0.5 Torr and high frequency power was set to 180W.

The surface potential, the photosensitivity, and the residual potential of the thus obtained photoreceptor were measured, and the following results were obtained. This measurement was carried out by charging with a -5.6 KV corona charger and then irradiating the surface of the photoconductor with spectral monochromatic light (650 nm).

The residual potential is a value 5 seconds after the start of exposure.

Surface potential ・ ・ ・ -600V Photosensitivity ・ ・ ・ 0.52cm ² erg ^-1 Residual potential ・ ・ ・ -35V On the other hand, when the 6th regulating valve (22) is closed to stop NO gas release, surface potential・ ・ ・ −500V Photosensitivity ・ ・ ・ 0.48cm ² erg ^-1 Residual potential ・ ・ ・ －35V.

(Example 2) In this example, the photoreceptor of the first aspect was manufactured under the conditions shown in Table 1, and the following electrophotographic characteristics were obtained.

Note that the electrophotographic characteristics are the same as in (Example 1) and are common to all of the present examples.

Surface potential ・ ・ ・ −750V Photosensitivity ・ ・ ・ 0.60cm ² erg ^-1 Residual potential ・ ・ ・ -30V (Example 3) In this example, the photoconductor of the second aspect was manufactured under the conditions shown in Table 2 and the following electrophotographic characteristics were obtained.

Surface potential ・ ・ ・ −770V Photosensitivity ・ ・ ・ 0.67cm ² erg ^-1 Residual potential ・ ・ ・ -30V (Example 4) In this example, a photoconductor of the third aspect was manufactured under the conditions shown in Table 3, and the following electrophotographic characteristics were obtained.

Surface potential ・ ・ ・ −800V Photosensitivity ・ ・ ・ 0.68cm ² erg ^-1 Residual potential ・ ・ ・ -25V (Example 5) In this example, a photoreceptor of the fourth mode was manufactured under the conditions shown in Table 4, and the following electrophotographic characteristics were obtained.

Surface potential ・ ・ ・ −840V Photosensitivity ・ ・ ・ 0.70cm ² erg ^-1 Residual potential ・ ・ ・ －35V [Advantages of the Invention] As described above, according to the electrophotographic photosensitive member of the present invention, a-SiC having photoconductivity over all layers has a high dark resistivity and is also excellent in photosensitivity characteristics. Thus, the surface protective layer and the carrier injection blocking layer can be substantially eliminated, and as a result, an electrophotographic photoreceptor including only the photoconductive a-SiC layer can be provided.

Further, according to the electrophotographic photosensitive member of the present invention, by containing a predetermined amount of oxygen in the film, the photosensitivity is improved, and further, the electrophotographic characteristics are improved in general. The body can provide.

Further, according to the electrophotographic photosensitive member of the present invention, the surface potential is improved and the photosensitivity characteristics are improved, and the residual potential is remarkably reduced by changing the contents of carbon and the Va group element in the layer thickness direction. be able to. In particular, when the carbon content is changed in the layer thickness direction, the resistivity is controlled and the required layer region is obtained, and as a result, a significantly high performance electrophotographic photoreceptor can be provided.

Further, according to the present invention, there is provided an electrophotographic photosensitive member for negative polarity, which can be favorably charged to negative polarity.

According to the electrophotographic photosensitive member of the present invention, since it is excellent in charging ability and environment resistance by itself, it is not necessary to provide a protective layer, and the photosensitive member is exposed to corona discharge or is a resin component of a developer, for example. When the surface is deteriorated by filming on the surface, even if the deteriorated surface is repeatedly subjected to polishing and regeneration with an abrasive or the like, the initial characteristics of the photoconductor can be maintained without being limited in the polishing amount. This makes it possible to stably supply a good image in the initial stage for a long period of time.

Furthermore, when a conventional a-Si photoconductor is used for a long period of time, local discharge breakdown of the photoconductor surface is likely to occur due to corona discharge, which causes spots on the image. Although there is a problem, according to the present invention, the relative permittivity of a-Si is ε = 12, whereas that of a-SiC is ε = 7, which is about half, and therefore the charging ability is excellent. , This allows
Even if the surface potential is increased, the above discharge breakdown does not occur, and as a result, a high quality and highly reliable electrophotographic photoreceptor is provided.

Further, when the electrophotographic photosensitive member of the present invention is compared with a conventional a-Si photosensitive member, a problem with this a-Si photosensitive member is that it is inferior in moisture resistance, so that image deletion easily occurs, and the charging ability is inferior. As a result, a ghost phenomenon occurs, but in order to solve this, a heater is used to heat the a-Si photoconductor at the time of use to prevent the a-Si photoconductor from occurring. On the other hand, the electrophotographic photosensitive member of the present invention has an advantage that it is not necessary to use a heater as described above because it has excellent moisture resistance and charging ability.

Further, the electrophotographic photosensitive member of the present invention can obtain a wide spectral sensitivity characteristic (peak 600 to 700 nm) and increase the photosensitivity itself by changing the carbon content as compared with the a-Si photosensitive member. Further, if an impurity element is doped as necessary, there is an advantage that sensitization on the long wavelength side can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view showing a layer structure of an electrophotographic photosensitive member of the present invention, FIG. 2 is an explanatory view showing a layer structure of a conventional electrophotographic photosensitive member, and FIG. Explanatory drawing showing the layer region of the photoconductor of the first aspect of the present invention, FIG. 4, FIG. 5, FIG. 6, FIG. 7, FIG.
FIG. 9 and FIG. 9 are explanatory views showing the carbon content of the photoconductor of the first aspect according to the present invention, and FIG. 10 is an explanatory view showing the layer regions of the photoconductor of the second aspect according to the present invention, 11 and 12
FIG. 13, FIG. 14, FIG. 14, FIG. 15 and FIG. 16 are explanatory views showing the carbon content of the photoconductor of the second aspect of the present invention, and FIG. 17 is the third diagram of the present invention. Explanatory drawing showing the layer region of the photoconductor of the aspect, FIG. 18, FIG. 19, FIG. 20 and FIG. 21 are explanatory diagrams showing the carbon content of the photoconductor of the third aspect of the present invention, respectively. FIG. 22 is an explanatory view showing a layer region of a photoreceptor of a fourth aspect according to the present invention, FIGS. 23 and 24 are explanatory views showing carbon content of the photoreceptor of the fourth aspect according to the present invention, 25th
The figure is an illustration of a capacitively coupled glow discharge decomposition apparatus used in an embodiment of the present invention. 1 ... Substrate 5,5a, 5b, 5c ... Photoconductive amorphous silicon carbide layer 6 ... First layer region 7 ... Second layer region 8 ... Third layer region 9 ... Fourth Layer area 10: Amorphous silicon carbide surface protection layer

Front page continuation (72) Inventor Hitoshi Takemura 6 1166, Haseno, Jikazo-cho, Yokaichi-shi, Shiga Prefecture Kyocera Corporation Shiga Yokaichi factory (72) Inventor, Akira Watanabe 6 Kyocera, 1166, Haseno-machi, Yokaichi-shi, Shiga Prefecture Shiga Yokaichi Co., Ltd. (72) Inventor Ishiyoshi Konoyoshi 6 16-1166 Haseno, Jamizocho, Yokaichi-shi, Shiga Prefecture Kyocera Co., Ltd. Shiga Yokaichi (56) Reference JP-A-61-100759 (JP, A) JP-A-57-119358 (JP, A) JP-A-59-87461 (JP, A) JP-A-60-112047 (JP, A)

Claims (1)

[Claims] 1. A substrate containing 5 to 50 atomic% carbon and 5 to 5 atomic% carbon.
Containing 50 atomic% hydrogen or halogen element, 5 × 10 ^{-5 to} 1 atomic% oxygen and 10,000 ppm or less (excluding 0) Group Va element in the periodic table, and having a dark resistivity of 10 ¹³ Ω ・It is formed by forming a photoconductive amorphous silicon carbide layer that is not less than cm and 1,000 times or more compared to the bright resistivity,
The amorphous silicon carbide layer comprises a first layer region, a second layer region and a third layer region arranged from the side of the substrate, and the third layer region contains more carbon than the second layer region. An electrophotographic photosensitive member capable of being negatively charged, which contains a large amount of the first layer region and a larger amount of a Va group element of the periodic table than the second layer region.