JPH0820744B2 - Electrophotographic photoreceptor - Google Patents

Description

TECHNICAL FIELD 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 to a positive polarity.

[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. Attention has been paid to this requirement because the amorphous silicon layer is excellent in heat resistance, abrasion resistance, pollution-free properties, photosensitivity characteristics and the like.

However, an amorphous silicon (hereinafter abbreviated as a-Si) layer can obtain only a dark resistivity of about 10 ⁹ Ω · cm unless it is 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. For this reason, elements such as oxygen and nitrogen can be doped in a very small amount to increase the resistance, but on the other hand, there is a problem that the photoconductivity decreases. Further, even if boron or the like is added, a higher resistance can be expected, but a dark resistivity that is sufficiently satisfactory cannot be obtained, and about 10% is obtained.
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 formed by laminating another non-photoconductive layer on the a-Si photoconductive layer.

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

According to this laminated layer photoreceptor, the carrier injection blocking layer (2) blocks the injection of carriers from the substrate (1), and the surface protection layer (4) is the a-Si photoconductive layer (3). The layer (2) and the layer (4) of both layers are intended to increase the dark resistivity of the photoconductor to enhance the charging ability. The layers need not be photoconductive.

As described above, the conventionally known a-Si electrophotographic photoconductor 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 regardless of the presence or absence of a doping agent. As described above, it was found that an electrophotographic photosensitive member which can be positively charged 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, such a large charging ability was obtained a-
Even in the case of a SiC photoconductor, when it is used, corona discharge, light irradiation, and the like are repeatedly performed, which causes a problem that the photosensitivity deteriorates with time.

In addition, the a-SiC photoconductor is easier to obtain a large charging ability than the a-Si photoconductor, which causes the image deletion and ghost phenomenon (the previous image is a problem when using the a-Si photoconductor). It remains without being completely removed, and the phenomenon that the previous image reappears with the next image formation) can be solved. However, a-SiC photoconductor is used under high temperature and high humidity. Alternatively, when it is used as a photoconductor for an ultra-high speed copying machine and itself requires very large environment resistance, heat resistance and durability that are sufficiently satisfactory have not yet been obtained.

[Object of the Invention]

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 the entire layer, and heat resistance. It is to provide a high-performance and long-term reliable electrophotographic photosensitive member which has improved durability and durability and can maintain excellent initial photosensitivity.

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

[Means for solving problems]

According to the present invention, photoconductive amorphous silicon containing 5 to 50 atomic% of carbon on a substrate, having a dark resistivity of 10 ¹³ Ω · cm or more and a light resistivity of 1,000 times or more. A carbide layer is formed, and the amorphous silicon carbide layer is formed on the first side of the substrate.
Layer region and a second layer region, and the second layer region contains 5 × 10 ^{−5 to} 25 atomic% fluorine and contains more carbon than the first layer region, There is provided a positively chargeable electrophotographic photosensitive member characterized in that the layer region 1 contains 0.1 to 10,000 ppm of a Group IIIa element of the periodic table.

 Hereinafter, the present invention will be described in detail.

The electrophotographic photosensitive member of the present invention is characterized in that the photoconductive a-SiC layer contains a fluorine (F) element within a predetermined range, and the photoconductive a-SiC layer is I
It has already been proposed by the present inventors that a photoreceptor having a Group IIa element contained therein can be positively charged.

That is, according to FIG. 1, a photoconductive a-SiC layer (5) is formed on the conductive substrate (1) by, for example, a glow discharge decomposition method, and carbon and IIIa are formed 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 could be made into a sufficiently practical a-SiC photoreceptor.

Furthermore, when the inventors of the present invention charge the a-SiC photoconductor in a positive polarity or a negative polarity and compare the charging performances of the two,
Group IIIa element in the SiC layer (5) in the range of 0.1 to 10,000 ppm,
It has also been found that doping in a range of preferably 0.1 to 1000 ppm can positively enhance the chargeability with positive polarity.

As described above, it has not yet been clarified that the doping with the Group IIIa element facilitates charging to the positive polarity.
Although it cannot be excluded from the speculation area, the a-SiC layer has a sufficiently high resistivity to hold positive charges, and also has an excellent effect of preventing the injection of negative charges from the substrate. It is thought that this is because of its excellent mobility.

Further, as the group IIIa element, there are B, Al, Ga, In and the like. Among them, B is desirable because it has an excellent covalent bond and can sensitively change the 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. When the present inventors conducted an experiment to confirm the presence or absence of photoconductivity by changing the carbon content ratio in various ways, a-Si
Carbon in the C layer (5) is 1 to 90 atom%, preferably 5 to 5
The carbon content may be within the range of 0 atomic%, or the carbon content may be varied within the range along the layer thickness direction.

According to the present invention, fluorine (F) is indispensable as the element for terminating the dangling bond, and this F is
× 10 ^-5 to 25 atomic%, preferably atomic structure the inclusion in the film in the range of 5 × 10 ^-5 to 10 atomic% is stabilized, it has been found that improved durability and heat resistance .

In addition, although the element for terminating the dangling bond has F as an essential component, it is usually a-containing H-containing gas such as SiH ₄ and C ₂ H _2.
It is also terminated by H for use as a gas for producing SiC. This H is more likely to be taken in at the end of the dangling bond than other monovalent elements, so that the localized level density in the band gap is reduced, which increases the doping efficiency of the impurity element and controls the valence electrons. Can be said to be desirable because it will be easier.

Further, according to the present invention, when F is contained, H tends to be incidentally contained. However, when F and H coexist, the bonding state of Si and H or C and H is further stabilized, which results in ,
It has been found that the doping efficiency of impurity elements and the control of valence electrons are further improved.

The total content of H and F is 5 to 50 atom%, preferably 5 to 40 atom%, and most preferably 10 to 30 atom%.
If it is less than 5 atomic%, the dangling bond cannot be terminated sufficiently and the chargeability and photosensitivity characteristics are deteriorated. If it exceeds 50 atomic%, the chain structure of Si and C increases. As a result, the film structure becomes less dense, defects occur, and the photosensitivity decreases.

The thickness of the photoconductive a-SiC layer (5) as described above may be at least 5 μm or more, and the surface potential becomes +
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 has a high surface potential, excellent photosensitivity characteristics, and a small residual potential.

Thus, a single composition of photoconductive a-SiC over the layer thickness direction
The layer alone is sufficient for practical use, and when F is further contained, it becomes a highly durable and highly heat resistant electrophotographic photoreceptor.

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

That is, according to the present invention, the content ratio of fluorine is changed over the layer thickness direction, whereby the content ratio is continuously changed or a plurality of layer regions are generated. The electrophotographic photosensitive member according to any one of the first to fifth aspects can be obtained.

Hereinafter, various aspects of the electrophotographic photosensitive member according to the present invention will be described in the third section.
This will be described with reference to FIGS. 5 to 7 and FIGS. 7 to 24.

First Aspect According to the first aspect, there is provided an electrophotographic photoreceptor in which a photoconductive a-SiC layer is formed on a substrate, wherein the a-SiC layer is 0.1 to
A layer region containing 10,000 ppm of Group IIIa element and containing F in the layer thickness direction is generated, and the F content ratio of this layer region gradually decreases from the substrate toward the surface of the photoconductor, and thus the layer can be charged positively. An electrophotographic photosensitive member is provided.

That is, according to the first aspect, the group IIIa element is contained in the photoconductive a-SiC layer having the single composition shown in FIG. 1 to control the valence electrons of the a-SiC layer. In addition, F is also added to form a layer region having high durability and high heat resistance so that the F content ratio is gradually decreased from the substrate toward the surface of the photoconductor, thereby contacting the substrate side. Or, since a large amount of F is contained in a region close to it, the doping efficiency of the group IIIa element is increased in that region,
As a result, an electrophotographic photosensitive member is obtained which has a high carrier injection preventing ability to raise the surface potential and a small residual potential, and which is positively charged to positive polarity with improved performance over the entire electrophotographic characteristics.

As an example showing the change in the F content efficiency, Figs.
There are 10 figures, the horizontal axis shows the layer thickness from the substrate to the photoreceptor surface, and the vertical axis is the F content.
As the content of Al increases, more of the group IIIa element is doped.

Second Aspect According to the second aspect, an electrophotographic photoreceptor having a photoconductive a-SiC layer formed on a substrate, wherein the a-SiC layer is 0.1 to
A layer region containing 10,000 ppm of a Group IIIa element and containing F in the layer thickness direction was generated, and the F content in this layer region was gradually increased from the substrate toward the surface of the photoreceptor. Provided is a characteristic positively chargeable electrophotographic photoreceptor.

That is, according to the second aspect, the group IIIa element is added to the photoconductive a-SiC layer having the single composition shown in FIG. 1 to control the valence electrons of the a-SiC layer. In addition, it also contains F to make it highly durable and highly heat resistant.
A layer region whose content ratio is gradually increased from the substrate to the surface of the photoconductor is generated, whereby the content ratio of F on the photoconductor surface is increased, and excellent heat resistance and durability are obtained. Excellent in corona discharge and improved in moisture resistance.

Examples of changing the F content ratio are shown in FIGS. 11 to 14, in which the horizontal axis represents the layer thickness from the substrate to the surface of the photoconductor and the vertical axis represents the F content.

Third Aspect According to a third aspect, there is provided an electrophotographic photosensitive member 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. The first layer region is located closer to the substrate than the second layer region and is 5 × 10 ⁻⁵
~ 25 atomic% F, second layer region 0.1 to 10,000
Provided is a positively chargeable electrophotographic photoreceptor, which contains 0 ppm of a Group IIIa element.

That is, according to the third aspect, at least the first layer region is formed by changing the atomic composition ratio in the layer thickness direction with respect to the single composition photoconductive a-SiC layer shown in FIG. And a second layer region are generated.
This will be described with reference to the drawings and FIGS. 15 to 18.

In FIG. 3, a photoconductive a-SiC layer in which a first layer region (6a) and a second layer region (7a) are sequentially formed on a conductive substrate (1) and both layer regions are integrated. It is composed of (5a), and in forming this layer region, it is determined by changing the composition ratio of Si and C, the content of the group IIIa element, the content of F, etc. It is important that the layer region (6a) contains 5 × 10 ^{−5 to} 25 atomic% of F and the second layer region (7a) contains 0.1 to 10,000 ppm of a Group IIIa element. is there.

The F content of the first layer region (6a) is appropriately determined within the range of 5 × 10 ^{−5 to} 25 atom%, preferably 5 × 10 ^{−5 to} 10 atom%, whereby high durability and high It becomes heat resistant.

The second layer region (7a) has a Group IIIa element content of 0.1 to 1
It is appropriately determined within the range of 0.00000 ppm, whereby it is possible to obtain positively charged electrophotographic characteristics such as surface potential and photosensitivity.

According to this third aspect, IIIa is present in the first layer region (6a).
A group element may be contained, and in this doping, since F is contained in the first layer region (6a), the doping efficiency is remarkably improved, whereby the carrier injection blocking ability is increased. To increase the surface potential and reduce the residual potential.

Then, when the first layer region (6a) containing a larger group IIIa element than the second layer region (7a) is formed, the photoconductive a-
The conductivity increases in the region of the SiC layer (5a) on the substrate side, which further prevents the injection of carriers from the substrate side, and the optical carriers generated in the entire region of the a-SiC layer flow smoothly to the substrate. As a result, the surface potential is further increased and the photosensitivity characteristics are improved.

Further, according to this aspect, it is desirable that the carbon content of the second layer region (7a) be higher than the carbon content of the first layer region (6a). The dark resistivity of (7a) increases, and as a result, the surface potential increases.

The first layer region (6a) has photoconductivity over the entire region, which results in the conventional a-Si shown in FIG.
It can be distinguished from the carrier injection blocking layer (2) of the electrophotographic photoreceptor. Then, the first layer region (6a) improves the photosensitivity characteristics overall due to the photoconductivity of the entire region. In particular, excellent photosensitivity characteristics can be obtained for light having a relatively long wavelength that easily reaches the first layer region (6a), which is suitable for an electrophotographic photosensitive member using a semiconductor laser as a recording light source. Becomes

Further, according to the conventional a-Si electrophotographic photoreceptor, the layer thickness of the carrier injection blocking layer (2) is set to 1/5 times or less that of the a-Si photoconductive layer (3). The first layer area (6
Even if the layer thickness of a) is 1 time or less as compared with the second layer region (7a), the residual potential can be made sufficiently small to improve the photosensitivity characteristics, and a suitable layer thickness ratio for that is 1/2 or less,
Optimally, it should be set to 1/4 or less.

The F content of the photoconductive a-SiC layer (5a) may be changed in the layer thickness direction.
There are 18 figures, the horizontal axis shows the layer thickness from the substrate to the photosensitive member surface, and the vertical axis shows the F content. Note that on this horizontal axis (6
The respective ranges shown in a) and (7a) represent the first layer region and the second layer region.

Fourth Aspect According to a fourth aspect, there is provided an electrophotographic photosensitive member 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. The first layer region is located closer to the substrate than the second layer region, and the second layer region contains 5 × 10 ^{−5 to} 25 atomic% F and has a first region.
There is provided a positively chargeable electrophotographic photoreceptor, characterized in that the layer region contains 0.1 to 10,000 ppm of the group IIIa element.

That is, according to the fourth aspect, by changing the atomic composition ratio in the layer thickness direction with respect to the photoconductive a-SiC layer having the single composition shown in FIG. 1, at least the first layer region is formed. And a second layer region are generated.
This will be described with reference to the drawings and FIGS. 19 to 21.

In FIG. 4, a photoconductive a-SiC layer in which a first layer region (6b) and a second layer region (7b) are sequentially formed on a conductive substrate (1) and both layer regions are integrated. It is composed of (5b) and is determined by changing the composition ratio of Si and C, the content of the group IIIa element, the content of F, etc. in forming this layer region. It is important that the second layer region (7b) contains 5 × 10 ^{−5 to} 25 atom% of F and the first layer region (6b) contains 0.1 to 10,000 ppm of the Group IIIa element.

F content 5 × 10 ^-5 to 25 atomic% of the second layer region (7b), preferably determined as appropriate within a range of 5 × 10 ^-5 to 10 atomic%, whereby the generation efficiency of photocarriers Is increased, the photosensitivity is improved, the durability and heat resistance of the film itself are improved, and particularly, the corona discharge is excellent and the moisture resistance is improved.

The first layer region (6b) has a Group IIIa element content of 0.1 to 10,
It is appropriately determined within the range of 000 ppm, and thereby, it is possible to obtain the required electrophotographic characteristics such as surface potential and photosensitivity characteristics while being positively charged.

Further, according to this aspect, it is desirable that the carbon content of the second layer region (7b) is higher than the carbon content of the first layer region (6b). The dark resistivity of (7b) increases, and as a result, the surface potential increases. The second layer region (7b) is formed to increase the resistance of the surface side of the photoconductive a-SiC layer (5b), and the conventionally known surface protection layer (4) described in FIG. ) Is completely distinguishable. In addition, according to the function-separated type photoreceptor, which is divided into 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 an exceptionally large photoconductivity. Is not required, and the photoconductivity is usually set to less than 1000 times the photoconductivity to dark conductivity. On the other hand, the second layer region (7b) has photoconductivity of 1000 times or more, and can be sufficiently distinguished from the carrier transport layer.

The layer thickness of the layer region (7b) in FIG. 4 is the same as that of the first layer region (6b).
Less than 1 time, preferably less than 1/2 times, optimally 1/4
It is desirable that it is preferably not more than twice, which significantly improves the surface potential, has excellent photosensitivity, and has a small residual potential.

The F content of the photoconductive a-SiC layer (5b) may be varied in the layer thickness direction.
There are 21 figures, the horizontal axis shows the layer thickness from the substrate to the surface of the photoreceptor, and the vertical axis shows the F content. Note that on this horizontal axis (6
The respective ranges shown in b) and (7b) represent the first layer region and the second layer region.

Fifth Aspect According to a fifth aspect, there is provided an electrophotographic photosensitive member 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 located closer to the substrate than the second layer area is, the second layer area is located closer to the substrate than the third layer area, and the first layer area and The third layer region is F compared to the second layer region.
The second layer region is 0.1 to 10,00
Provided is a positively chargeable electrophotographic photoreceptor, which contains 0 ppm of a Group IIIa element.

That is, according to the fifth aspect, at least the first layer region is formed by changing the atomic composition ratio in the layer thickness direction with respect to the single composition photoconductive a-SiC layer shown in FIG. To 3rd layer area | region, this aspect is demonstrated with FIG. 5 and FIG. 22 to FIG.

In FIG. 5, a first layer region (6c), a second layer region (7c) and a third layer region (8c) are sequentially formed on a conductive substrate (1), and these layer regions are substantially formed. Integrated with a-SiC
The layer (5c) is formed, and in forming this layer region, it is determined by changing the composition ratio of Si and C, the content of the group IIIa element, the content of F, etc.
Layer group (7c) contains 0.1 to 10,000 ppm of a group IIIa element, and the first layer (6c) and the third layer region (8c) have F
It is important that both layers (6c) and (8c) contain more F than the second layer region (7c).

That is, the second layer region (7c) has a Group IIIa element content of 0.
The content is appropriately determined within the range of 1 to 10,000 ppm, whereby the desired electrophotographic characteristics such as surface potential and photosensitivity characteristics can be obtained while being charged positively.

The third layer region (8c) is formed on the second layer region (7a) of the a-SiC layer (5a) described in the third aspect, whereby the photoconductive a -The durability and moisture resistance on the surface side of the SiC layer (5c) are enhanced, and as a result, a photoreceptor having excellent environment resistance, no image deletion, and a long life can be obtained.

The third layer region (8c) is completely different from the conventionally known surface protective layer (4) shown in FIG.
Further, according to the function-separated type photoreceptor, which is divided into the photocarrier generation layer and the carrier transport layer, the carrier transport layer is 10 ¹³ Ω.
・ High resistance to cm or more, but this layer is not required to have a particularly large photoconductivity, and the photoconductivity to dark conductivity is usually set to less than 1000 times the photoconductivity. Not too much. On the other hand, the third layer region (8c) 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 (8c) is preferably 1 time or less, preferably 1/2 time or less, and optimally 1/4 time or less as compared with the second layer region (7c). 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.

The first layer region (6c) is substantially the same as the first layer region (6a) of the a-SiC layer (5a) described in the third aspect, and its configuration and operational effects are as described above. is there.

According to the fifth aspect, the F content distribution of the photoconductive a-SiC layer (5c) is as shown in FIGS. 22 to 24, and the horizontal axis represents the layer thickness direction from the substrate to the surface of the photoconductor. And the vertical axis is F
Indicates the content. In addition, on this horizontal axis, (6c) (7c)
The respective ranges shown in (8c) represent the first layer region, the second layer region, and the third layer region.

Thus, according to the first to fifth aspects, there is provided an electrophotographic photosensitive member having electrophotographic characteristics generally improved as compared with the single-composition a-SiC photosensitive member shown in FIG. .

According to the present invention, the first layer region (6a) (6b) (6c) in each of the above-mentioned various embodiments contains 0.01 to 60 atom% of at least one of oxygen and nitrogen, preferably 0.1 to 30 atom%. It is good to contain it within the range of atomic%,
The adhesion of the a-SiC layer to the substrate is improved.

Further in accordance with the present invention, a single composition a-SiC layer and a first
All of the a-SiC layers of the fifth to fifth aspects are 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.

For 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-Si.
C, SiO ₂ ,, SiO, Al ₂ O ₃ , SiC, Si ₃ N ₄ ,, a-Si, a-Si: H, a-Si: F, a-Si
Inorganic materials such as C: 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 glow discharge decomposition method, an ion plating method, a reactive sputtering method, a vacuum deposition method, a thin film forming technique such as a CVD method can be used, and is also used for this Raw material is solid,
Either liquid or gas may be used.

Hereinafter, the case where the electrophotographic photosensitive member of the present invention is manufactured by the glow discharge decomposition method will be described as an example.

The a-SiC generation gas contains a Si-containing gas and a C-containing gas, and if necessary, contains H ₂ and an inert gas (He, Ar, etc.) as a carrier gas. This Si-containing gas contains Si
H ₄ , Si ₂ H ₆ , Si ₃ H ₈ , etc., and C-containing gas is CH ₄ , C
_{2 H 6, C 2 H 4} , include _{C 2 H 2, C 3 H} 8, or Si (CH ₃₎ with Si-C bonds ₄ gas or the like may be used.

When F is contained in the a-SiC forming gas, it may be bonded as a monovalent element to the Si-containing gas or the C-containing gas, for example, SiF ₄ , SiHF ₃ , SiH ₂ F ₂ , SiH ₃ F, CH ₃ F, CH
_{There are 2} F ₂ , CHF ₃ and CF ₄ . Further, F may be mixed in the a-SiC generating gas or the glow discharge region as an impurity or inevitably, so that F may be contained in the film forming process. For example, HF is used as a cleaning agent for the reaction container for glow discharge decomposition, but may remain and be mixed during the formation of the a-SiC layer.

In order to contain the Group IIIa element in the range of 0.1 to 10,000 ppm in the a-SiC layer, the gas for a-SiC production contains 10 ^{−6 to} 1 mol%, preferably 10 ^{−6 to} 0.1 mol% of the Va group. It suffices to contain an element-containing gas, and this doping gas contains B ₂ H ₆ and BF.
_{3, Al (CH 3),} Ga (CH 3), Im (CH 3) is _3, and the like.

In producing the electrophotographic photosensitive member of the present invention, Si-containing gas and acetylene (C ₂
When a-SiC is formed from a mixed gas of H ₂ ) gas, it is desirable in that a significantly high speed film forming property can be achieved.

According to experiments conducted by the inventors of the present invention, various Si-based gases described above can be used as the Si-containing gas. For example, when SiH ₄ gas and C ₂ H ₂ gas are used,
A film formation rate of up to 20 μm / hour was obtained. Because SiH ₄ gas and CH
_When an a-SiC film is formed using ₄ gases, the film formation rate is about 0.3 to 1 μm / hour.

Further, according to the production method of the present invention, when introducing C ₂ H ₂ and Si-containing gas into the glow discharge region, the gas composition ratio
It may be set within the range of 0.01: 1 to 3: 1, preferably 0.05: 1 to 1: 1, and optimally within the range of 0.05: 1 to 0.3: 1.
If the ratio deviates from the ratio of 1: 1, the dark resistivity becomes 10 ¹¹ Ω ・ cm or less, the charge retention is insufficient, and a large charging potential cannot be obtained. In this case, the dangling bond in the film increases and the dark resistivity becomes 10 ¹¹
Ω · cm or less.

According to the production method of the present invention, in producing the a-SiC layer under the production conditions as described above, the high frequency power for glow discharge, the gas pressure inside the reaction chamber and the substrate temperature are set as follows. Is good.

That is, the high frequency power may be set in the range of 0.05 to 0.5 W / cm ² , and if it is less than 0.05 W / cm ² , the film forming rate becomes low, and if it exceeds 0.5 W / cm ² , the film quality deteriorates due to plasma damage. As a result, carrier mobility decreases. Also, the gas pressure may be set within the range of 0.1 to 2.0 Torr.
If it is less than 2.0, the film formation rate becomes small, and if it exceeds 2.0 Torr, the discharge becomes unstable. Further, the substrate temperature is preferably higher by about 30 to 80 ° C. than in forming the a-Si: H film, and more preferably in the range of 200 to 400 ° C. If the substrate temperature is lower than 200 ° C., the network formation of Si and C is hindered, and if it exceeds 400 ° C., desorption of hydrogen becomes remarkable and the dark resistivity becomes small.

Next, the production methods for the above-described first to fifth aspects of the electrophotographic photosensitive member of the present invention are listed below. In any of the manufacturing methods, C ₂ H ₂ is used as a C-containing gas to increase the film formation rate.

According to the production method of the first aspect, according to the production method of the first aspect, an electrophotographic photoconductor in which a photoconductive a-SiC layer capable of being positively charged by glow discharge decomposition of an a-SiC generating gas is formed on a substrate. In the method for producing a body, the gas contains 10 ^{−6 to} 1 mol% of a Group IIIa element-containing gas, C ₂ H ₂ and Si-containing gas, and contains F, and F in the gas during film formation. There is provided a process for producing an electrophotographic photosensitive member, characterized in that the content ratio is gradually decreased.

Production Method of Second Aspect According to the production method of the second aspect, an electrophotographic photoconductor in which a photoconductive a-SiC layer capable of being positively charged by glow discharge decomposition of an a-SiC generating gas is formed on a substrate In the method for producing a body, the gas contains 10 ^{−6 to} 1 mol% of a Group IIIa element-containing gas, C ₂ H ₂ and Si-containing gas, and contains F, and F in the gas during film formation. There is provided a method for producing an electrophotographic photosensitive member, characterized in that the content ratio is gradually increased.

Production Method of Third Aspect According to the production method of the third aspect, an electrophotographic photoconductor in which a photoconductive a-SiC layer capable of being positively charged by glow discharge decomposition of an a-SiC generating gas is formed on a substrate. A method of manufacturing a body, wherein the gas comprises C ₂ H ₂ and a Si-containing gas, and the gas composition ratio is changed during film formation so that the layer has 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 the a-SiC generating gas contains F during the formation of the first layer region, and the a-Si layer is formed during the formation of the second layer region.
There is provided a process for producing an electrophotographic photosensitive member, characterized in that the gas for C generation contains 10 ^{−6 to} 1 mol% of a Group IIIa element-containing gas.

Production Method of Fourth Aspect According to the production method of the fourth aspect, an electrophotographic photoconductor in which a photoconductive a-SiC layer capable of being positively charged by glow discharge decomposition of an a-SiC generating gas is formed on a substrate A method of manufacturing a body, wherein the gas is composed of C ₂ H ₂ and Si-containing gas, and a gas composition ratio is changed during film formation to form at least a first layer region and a second layer region in the a-SiC layer. The first layer region is disposed closer to the substrate than the second layer region, and a-
An electrophotographic photosensitive member characterized in that the SiC forming gas contains F and the a-SiC forming gas contains 10 ^{−6 to} 1 mol% of a Group IIIa element-containing gas when forming the first layer region. A body formula is provided.

Production Method of Fifth Aspect According to the production method of the fifth aspect, an electrophotographic photoconductor in which a photoconductive a-SiC layer capable of being positively charged by glow discharge decomposition of an a-SiC generating gas is formed on a substrate A method of manufacturing a body, wherein the gas is composed of C ₂ H ₂ and Si-containing gas, and the gas composition ratio is changed during film formation so that at least a first layer region, a second layer region and a-SiC layer are formed. A third layer region, the first layer region is disposed closer to the substrate side than the second layer region, the second layer region is disposed closer to the substrate than the third layer region, and the first layer region and the third layer region are respectively disposed.
Of a-Si when forming the second layer region compared to when forming the second layer region
Electrophotography characterized in that the C-forming gas contains a large amount of F and the a-SiC forming gas contains 10 ^{−6 to} 1 mol% of a Group IIIa element-containing gas during formation of the second layer region. A method of making a photoreceptor is provided.

Next, the 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 (9) (10)
(11) (12) (13) (14) have SiH ₄ , C ₂ H ₂ , and
_{B 2 H 6 (H 2 0.2} % containing gas _{dilution), B 2 H 6 (H} 2 gas diluted with 3
(Containing 8 ppm), H ₂ and SiF ₄ gas are sealed, and H ₂ is also used as a carrier gas. These gases correspond to the corresponding 1st, 2nd, 3rd, 4th and 5th 6th regulating valves (15) (16) (17)
It is released by opening (18) (19) (20) and its flow rate is mass flow controller (21) (22) (23).
Controlled by (24), (25) and (26), it is sent to the main pipe (27). Incidentally, (28) is a stop valve. The gas flowing through the main tube (27) is sent to the reaction tube (29), and the capacitive coupling type discharge electrode (30) is installed inside the reaction tube (29), and the high frequency power applied to the electrode is provided. 50W to 3
kW and a frequency of 1 MHz to 50 MHz are suitable. Inside the reaction tube (29), a cylindrical film formation substrate (31) made of aluminum is placed on the sample holder (32),
The holding table (32) is driven to rotate by a motor (33), and the substrate (31) 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. Furthermore, the inside of the reaction tube (29) is in a high vacuum state (discharge voltage 0.1 to 2.0T) when the a-SiC layer is formed.
It is connected to the rotary pump (34) and the diffusion pump (35) by requiring the orr.

In the glow discharge decomposition apparatus configured as described above, for example, when an a-Sic film (containing B and F) is formed on the substrate (31), the first, second, third, and 5, 6th adjusting valve (1
5) (16) (17) (19) (20) open and SiH from each
_It releases ₄ , C ₂ H ₂ , B ₂ H ₆ , H ₂ , and SiF ₄ gases. Mass flow controller (21) (22) (23) (25) (26)
And is poured into the reaction pipe (29) through the main pipe (27). Then, the inside of the reaction tube (29) is in a vacuum state of about 0.1 to 2.0 Torr, the substrate temperature is 200 to 400 ° C.,
Along with the high frequency power of the capacitive discharge electrode (30) being set to 50 W to 3 kW or the frequency being set to 1 MHz to 50 MHz, glow discharge occurred and gas was decomposed to contain F and B. -SiC film is formed on the substrate at high speed.

〔Example〕

 Next, examples of the present invention will be described.

(Example 1) In this example, a photoconductive a-SiC layer having a uniform single composition in the layer thickness direction was formed on an aluminum film-forming substrate (31), and electrophotographic identification was measured.

That is, using the capacitively coupled glow discharge decomposition apparatus shown in FIG. 6, SiH ₄ gas from the first tank (9) at a flow rate of 150 sccm and C ₂ H ₂ gas from the second tank (10) at a flow rate of 10 sccm. Then, B ₂ H ₆ gas from the fourth tank (12) at a flow rate of 70 sccm,
H ₂ gas from the 5th tank (13) at a flow rate of 200sccm
SiF ₄ gas was discharged from the tank (14) at a flow rate of 50 sccm, and an a-SiC layer having a thickness of about 30 μm was produced based on the glow discharge decomposition method. As the manufacturing conditions, the substrate temperature was set to 300 ° C., the gas pressure was set to 0.57 Torr, and the high frequency power was set to 180 W.

The surface potential, photosensitivity and temperature characteristics 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 photosensitive member with monochromatic light (650 nm) which was dispersed. The temperature characteristic represents the amount of decrease in surface potential per 1 ° C. increase in the surface temperature of the photosensitive member. The smaller this value, the better the temperature characteristic and the more stable the charging ability.

Surface potential… + 630V Photosensitivity… 0.36cm ² erg ⁻¹ Temperature characteristic… 2.0V / ℃ On the other hand, when the sixth regulating valve (20) is closed to stop the release of SiF ₄ gas, the electrophotographic characteristic is the surface potential. … + 580V Photosensitivity… 0.38cm ² erg ⁻¹ Temperature characteristic… It became 5.8V / ℃, and the deterioration of temperature characteristic became remarkable.

(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. In this fabrication, the mass flow controller (26) was controlled to exponentially reduce the amount of SiF ₄ gas released to zero at the end of film formation from immediately after the start of glow discharge. The measurement of the electrophotographic characteristics is the same as in (Example 1), and is common to all of the examples.

Surface potential… + 690V Photosensitivity… 0.42cm ² erg ⁻¹ Temperature characteristic… 2.5V / ℃ (Example 3) In this example, the photoconductor of the second embodiment was manufactured under the conditions shown in Table 2, and the following electrophotographic characteristics were obtained. In this fabrication, the mass flow controller (26) was controlled to release SiF ₄ gas from the start of glow discharge, and the amount of release during film formation was gradually increased.

Surface potential… ＋ 670V Photosensitivity… 0.45cm ² erg ⁻¹ Temperature characteristic… 2.2V / ℃ (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… + 760V Photosensitivity… 0.43cm ² erg ⁻¹ Temperature characteristics… 2.8V / ℃ (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… + 710V Photosensitivity… 0.45cm ² erg ⁻¹ Temperature characteristics… 3.0V / ℃ (Example 6) In this example, a photoreceptor of the fifth aspect was produced under the conditions shown in Table 5, and the following electrophotographic characteristics were obtained. Further, the ghost phenomenon did not occur at all, and after the printing durability test of 200,000 sheets, the photosensitivity did not conspicuously decrease, and image fog did not occur.

Surface potential… + 820V Photosensitivity… 0.47cm ² erg ⁻¹ Temperature characteristics… 2.7V / ℃ [Advantages of the Invention] As described above, according to the electrophotographic photoreceptor of the present invention, a-SiC having a photoconductive material over all layers has a high dark resistivity and is also excellent in photosensitivity characteristics. Thus, the surface 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 F in the film, heat resistance and durability can be enhanced and excellent photosensitivity at the initial stage can be maintained, whereby high performance and long-term It can provide reliable electrophotographic properties.
By changing the F content in the layer thickness direction, the doping efficiency of the Group IIIa element can be increased to improve the carrier injection blocking ability, or the moisture resistance or the environment resistance can be improved.

Further, according to the electrophotographic photosensitive member of the present invention, the surface potential is improved and the photosensitivity characteristics are enhanced by changing the contents of carbon and the element IIIa over the layer thickness direction, and the residual potential is remarkably reduced. You can 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, an electrophotographic photoreceptor having a remarkably high performance can be provided.

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

According to the electrophotographic photosensitive member of the present invention, since it is excellent in charging ability and environmental resistance by itself, it is not particularly necessary to provide a protective layer, and for example, a photosensitive member exposed to corona discharge or a resin component of a developer is used. When the surface is deteriorated due to filming on the surface, the initial characteristics of the photoconductor can be maintained without limitation in the polishing amount even if the deteriorated surface is repeatedly subjected to polishing and regeneration with an abrasive, etc. As a result, a good image in the initial stage can be stably supplied over 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 easily occurs due to corona discharge, which causes spots on the image. However, 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. Therefore, 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, the problem with this a-Si photosensitive member is that it is inferior in moisture resistance and therefore image deletion easily occurs, and in addition, inferior in charging ability As a result, a ghost phenomenon occurs, but in order to solve this, when the a-Si photoconductor is used, the photoconductor is heated with a heater to prevent the occurrence. 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 simply 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 drawings]

FIG. 1 is an explanatory diagram showing a layer structure of an electrophotographic photosensitive member of the present invention, FIG. 2 is an explanatory diagram showing a layer structure of a conventional electrophotographic photosensitive member, and FIG. 3 is a third embodiment of the present invention. Explanatory drawing showing the layer area of the photoreceptor, FIG. 4 is an explanatory drawing showing the layer area of the photoreceptor of the fourth aspect of the present invention, and FIG. 5 is the layer of the photoreceptor of the fifth aspect of the present invention. FIG. 6 is an explanatory view showing a region, FIG. 6 is an explanatory view of a capacitively coupled glow discharge decomposition apparatus used in an embodiment of the present invention, and FIGS. 7, 8, 9, and 10 show the first embodiment. Explanatory drawing showing the fluorine content of the photoconductor, FIG. 11, FIG.
FIGS. 13, 13 and 14 are explanatory views showing the fluorine content of the photoconductor of the second embodiment, and FIGS. 15, 16, 17 and 18 show the photoconductor of the third embodiment. Explanatory diagram showing the fluorine content,
19, FIG. 20 and FIG. 21 are explanatory views showing the fluorine content of the photoconductor of the fourth embodiment, FIG. 22, FIG. 23 and FIG.
FIG. 6 is an explanatory view showing the fluorine content of the photoconductor of the embodiment. 1 ... Substrate 5,5a, 5b, 5c ... Photoconductive amorphous silicon carbide layer 6a, 6b, 6c ... First layer region 7a, 7b, 7c ... Second layer region 8c ... Third layer Layer area

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hitoshi Takemura 6 1166, Haseno, Jamizo-cho, Yokaichi-shi, Shiga Prefecture Kyocera Corporation Shiga Yokaichi factory (72) Inventor Akira Watanabe 1166, Haseno, Namizo-cho, Yokaichi-shi, Shiga Prefecture No. 6 Kyocera Co., Ltd. Shiga Yokaichi Factory (72) Inventor Kokichi Ishigaki 6166, Kyocera Co., Ltd. Shiga Yokaichi Factory, No. 1166, Haseno, Jamizo-cho, Yokaichi City, Yokaichi City, Shiga Prefecture (56) Reference JP-A-60-185956 (JP) , A) JP-A-57-119358 (JP, A) JP-A-59-119359 (JP, A) JP-A-59-119360 (JP, A)

Claims (1)

[Claims] 1. A photoconductive amorphous silicon carbide containing 5 to 50 atomic% of carbon on a substrate, having a dark resistivity of 10 ¹³ Ω · cm or more and 1,000 times or more as compared with the bright resistivity. Forming a layer, the amorphous silicon carbide layer comprising a first layer region and a second layer region arranged from the side of the substrate, and the second layer region is 5 × 10 ^{−5 to} 25 atoms. % Containing fluorine 1st
Contains more carbon than the first layer region, and the first layer region contains 0.
A positively chargeable electrophotographic photosensitive member containing 1 to 10,000 ppm of a Group IIIa element of the periodic table.