JP2003107767A - Electrophotographic photoreceptor and method of manufacturing electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To greatly improve the image quality of an electrophotographic photoreceptor which includes at least a conductive substrate, a photoconductive layer composed of a non-single crystalline material consisting of silicon atoms as its parent body, an upper inhibition layer and a surface layer for protecting the surface by attaining the compatibility of a cost reduction with the improvement in electrostatically chargeability and the reduction of characteristic unevenness with a higher dimension and reducing the flow of the images and the microcracks arising on the surface of the electrophotographic photoreceptor. SOLUTION: The electrophotographic photoreceptor for negative charge comprising using the film satisfying all of the conditions as an upper blocking layer; the film contains a non-single crystalline material consisting of silicon atoms and carbon atoms as its parent body and contains periodic table group 13 elements; the dark electrical conductivity σ0 in the initial state before casting light thereto is >=10<-15> to <=10<-10> S/cm; the change rate (σ0 -σ1 )/σ0 of the dark electrical conductivity is >=10% when the dark electrical conductivity after irradiation of the film with the light of the wavelength converted to 90% of an optical energy band gap for 120 minutes at intensity 4 mW/cm<2> is defined as σ1 and the method of manufacturing the same.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member sensitive to electromagnetic waves and a method for manufacturing the same.

[0002]

2. Description of the Related Art In the field of image formation, a photoconductive material for forming a light receiving layer in a light receiving member has high sensitivity,
High SN ratio (photocurrent (Ip) / dark current (Id)), having an absorption spectrum that matches the spectral characteristics of the electromagnetic wave to be irradiated, having fast photoresponsiveness, and having the desired dark resistance value, during use It is required to have characteristics such as being harmless to the human body. Particularly, in the case of an electrophotographic photosensitive member incorporated in an electrophotographic apparatus used as an office machine in an office, the pollution-free property at the time of use is an important point.

Amorphous silicon (hereinafter referred to as "a-Si") is a photoconductive material exhibiting excellent properties in this respect, and it has been attracting attention as a light receiving member for an electrophotographic photoreceptor.

In such a light receiving member, a conductive substrate is generally heated to 50 ° C. to 350 ° C., and a vacuum deposition method, a sputtering method, an ion plating method, or the like is applied to the substrate.
A photoconductive layer made of a-Si is formed by a film forming method such as a thermal CVD method, a photo CVD method, or a plasma CVD method. Among them, plasma CVD method, that is, the source gas is decomposed by high frequency or microwave glow discharge, and a-Si is deposited on the substrate.
The method of forming a deposited film has been put into practical use as a suitable method.

For example, Japanese Patent Laid-Open No. 57-115556 discloses a-
The photoconductive member having a photoconductive layer composed of a Si deposited film is electrically, optically, such as dark resistance value, photosensitivity, and photoresponsiveness,
In order to improve the use environment characteristics such as photoconductive characteristics and moisture resistance, and further the stability over time, a non-conductive layer containing silicon atoms and carbon atoms is formed on the photoconductive layer composed of an amorphous material with silicon atoms as a base material. Techniques for providing a surface barrier layer composed of a photoconductive amorphous material are described. Further, Japanese Patent Application Laid-Open No. 60-67951 discloses a technique for a photoconductor in which a translucent insulating overcoat layer containing a-Si, carbon, oxygen and fluorine is laminated.
Japanese Unexamined Patent Publication No. 62-168161 describes a technique of using, as a surface layer, an amorphous material containing silicon atoms, carbon atoms, and 41 to 70 atomic% hydrogen atoms as constituent elements.

Further, Japanese Patent Application Laid-Open No. 62-028764 discloses a photoconductor comprising a charge blocking layer, a photoconductive layer, an intermediate layer, and a surface modification layer, which is group IIIa (group 13) or group IIIa of the periodic table. Disclosed is a photoreceptor having an intermediate layer made of amorphous hydrogenated and / or fluorinated silicon doped with a Va group (Group 15) element and containing at least one of carbon atom, nitrogen atom and oxygen atom. . Also, the patent registration number
No. 2566762 discloses a negative charge in which a carrier injection blocking layer made of a-Si containing Va (group 15) element, a carrier transport layer made of a-Si, a carrier generation layer made of a-SiC, and a surface layer are sequentially laminated. A technique for obtaining an electrophotographic photoreceptor for use is disclosed.

These techniques have improved the electrical, optical and photoconductive properties of the electrophotographic photosensitive member and the use environment properties, and the image quality has been improved accordingly.

In addition, various proposals have been made from the viewpoint of production technology, and various ideas have been made for further various improvements by changing the method of supplying high frequency power.

For example, in Japanese Patent Laid-Open No. 56-045760, a plurality of power supplies having different frequencies, for example, 13.56 MHz and 400 kHz are applied to the same electrode as a power supply for exciting the reaction gas to excite the reaction gas. However, a technique of forming a deposited film on a substrate to be processed is disclosed.

Further, in Japanese Patent Laid-Open No. 60-160620, 10
A configuration is disclosed in which high frequency power of MHz or higher and high frequency power of 1 MHz or lower, for example, 13.56 MHz and 100 kHz are supplied to the same electrode.

On the other hand, in recent years, a plasma CVD method using a high-frequency power source with a higher frequency has been reported (Plasma Chem).
istry and Plasma Processing, Vol.7, No.3, (198
7), p267-273), there is a possibility that the deposition rate can be improved without deteriorating the performance of the deposited film by increasing the discharge frequency higher than the conventional 13.56 MHz. There is. By this method, it is expected that cost reduction and quality improvement of products can be achieved at the same time.

For example, Japanese Unexamined Patent Publication (Kokai) No. 6-287760 discloses an apparatus and method for PCVD using a frequency in the VHF band which can be used for forming a light receiving member for a-Si system electrophotography.

Further, as an example in which the above-mentioned method of using two kinds of high frequency power and a high frequency of a higher frequency are combined, Japanese Patent Laid-Open No. 7-074159 discloses a plasma processing method for cleaning a substrate. High-frequency power and low-frequency power on the electrode on which is mounted, for example, 60 MHz and 400 kHz
The technique of controlling the self-bias voltage that determines the collision energy of positive ions by supplying the high-frequency power of the above and changing the power value of the low-frequency power is disclosed.

[0014]

However, the conventional
The a-Si-based electrophotographic photosensitive member is advantageous in terms of electrical resistance, optical property such as dark resistance, photosensitivity, and photoresponsiveness, and use environment characteristics, as well as stability with time and durability. ,
Although the characteristics of each are individually improved, there is room for further improvement in order to improve overall characteristics. In addition, there is also a demand for a technique for significantly reducing the cost while improving or maintaining these characteristics.

In particular, the high image quality, high speed, and high durability of the electrophotographic apparatus are rapidly progressing. In the electrophotographic photosensitive member, the chargeability and the sensitivity are maintained while the electric characteristics and the photoconductive characteristics are further improved. However, it is required to significantly improve the performance under all environments.

For example, when an electrophotographic photosensitive member composed of an a-Si type material is used as a negative charging electrophotographic photosensitive member,
Higher performance can be expected because electrons, which have higher mobility than holes, can be used as the main carrier, and the same process is used as the electrophotographic process for organic photoconductors, which is generally negatively charged. It is considered to have great advantages, such as the possibility that it will be easier to do. However, compared to the case of using the positive charging, the injection of charges from the surface layer side is relatively likely to occur, and it is expected that there are drawbacks such as difficulty in obtaining charging ability. Therefore, it is desirable to provide an upper blocking layer to block the injection of electrons from the surface as much as possible, and how to improve this upper blocking layer is the key to improving the characteristics.
In particular, with the recent increase in speed and size of electrophotographic devices,
As the charging device becomes smaller and the speed at which the object to be copied passes through the copying process (hereinafter referred to as the process speed) increases, the passing time of the photoconductor inside the charger and during latent image exposure becomes shorter, and the high charging ability is improved. With the increasing demand for high-sensitivity photoreceptors, the importance of the upper blocking layer is increasing.

This upper blocking layer has a great influence on the characteristics of the photoreceptor, and therefore must be carefully formed. For example, if the film has a large absorption coefficient at the exposure wavelength, the decrease in sensitivity cannot be ignored, or in some cases,
Staebler W well known for amorphous silicon
Care must be taken because there is a possibility that the carrier traveling property will deteriorate due to a photodegradation phenomenon such as the ronski effect.
However, until now, the photodegradation phenomenon in this upper blocking layer,
As for the influence of the photodegradation on the electrophotographic characteristics, much attention has not been paid to it, and there are many unclear points.

Further, for example, if the film thickness unevenness in the upper blocking layer in the axial direction of the cylindrical photosensitive member is more than a certain extent, uneven charging ability may be a problem. This unevenness is considered to include not only the unevenness of the capacitance depending on the film thickness but also the unevenness of the charging ability depending on the difference of the injection amount. Therefore, the unevenness of the film thickness of the upper blocking layer is smaller than that of the photoconductive layer. Even a minute unevenness in film thickness causes a serious problem. Further, if the amount of the Group 13 element added as a dopant is not properly controlled, carriers may accumulate and flow laterally, which may cause an image to flow.

Further, particularly when negative charging is performed using a corona charger, very rarely microscopic cracks may occur. This factor is caused by ozone products (NOx, etc.)
It is conceivable that the number of molecules generated is higher than that of positive charging, and more molecules such as nitric acid are generated on the surface of the electrophotographic photosensitive member, so that the surface is easily damaged. In addition, if there is a weak binding part near the surface, especially near the boundary between the surface layer and the photoconductive layer with different stresses, the above-mentioned damage and slight stimuli (shock, friction, etc.) are combined and trigger, We believe that a small amount of cracks will occur around the weak bond.
If such a crack occurs, it may not be practically usable as an electrophotographic photoreceptor.

Therefore, when designing an electrophotographic photosensitive member, improvements should be made from a comprehensive viewpoint such as the layer structure of the electrophotographic photosensitive member and the chemical composition of each layer so as to solve the above-mentioned problems. In particular, in the case of a negatively charged photoreceptor, it is required to optimize the composition, dopant concentration, and preparation conditions of the upper blocking layer among the layers.

In addition, a search is also being made for a new production technique that can improve the performance and at the same time reduce the cost. One of them is a VHF band having a frequency higher than that of the conventional RF band or a frequency in the vicinity thereof. A plasma CVD method using high-frequency power has been earnestly studied. This V
In the plasma CVD method using the high frequency of the HF band, a good film can be obtained by appropriately selecting the conditions as compared with the case of using the high frequency of the RF band. However, in the case of a large area film, there is a problem in uniformity. May occur. That is, when the high frequency power in such a frequency band is used, the wavelength of the high frequency power in the vacuum container becomes the same length as the vacuum container, the high frequency electrode, the substrate, the substrate holder, etc. There was a case where the electric power formed a standing wave. If a standing wave is formed, the strength of the electric power is generated in each place in the vacuum container, and the plasma characteristics are different. Therefore, it is difficult to obtain a uniform vacuum processing characteristic in a wide range. As a means for solving such a problem, it is possible to simultaneously supply high-frequency power of a plurality of different frequencies into the reaction container as mentioned in the prior art. However, at present, the homogenization has not been achieved to the level desired for recent electrophotographic photoreceptors. Therefore, it is desired to suppress the unevenness of the film characteristic peculiar to the VHF band, improve the production efficiency by depositing a high-quality photoconductor at a high speed, and achieve a high level of both the characteristic improvement and the cost reduction. ing.

Further, the characteristics of the film formed by using the high frequency wave in the VHF band may be slightly different from the characteristics of the film formed by using the high frequency wave in the RF band even if the conditions are made as uniform as possible. It is considered that this is because the bonding method is slightly different due to the difference in energy of the active species in the plasma CVD process, but it is unknown in detail. Therefore, the above-mentioned chemical composition and dopant concentration required for the upper blocking layer may be different from those of the film obtained by the conventional fabrication method, and the degree of change of the film due to light irradiation is also different from that of the conventional film. In some cases, there are many unclear points. Therefore, it has been required to establish an upper blocking layer that can obtain optimum electrophotographic characteristics, especially when a high frequency VHF band having many advantages is used.

An object of the present invention is to solve various problems in the above-mentioned conventional electrophotographic photosensitive member for negative charging composed of a-Si.

That is, the main object of the present invention is to improve the charging ability, reduce the characteristic unevenness, and reduce the cost at a high level, and at the same time, reduce the image deletion and minute cracks generated on the surface of the electrophotographic photosensitive member. It is an object of the present invention to provide an electrophotographic photosensitive member for negative charging, which is made of a non-single-crystal material having a silicon atom as a base material and whose quality is dramatically improved, and a manufacturing method thereof.

The electrical, optical, and photoconductive properties are substantially stable regardless of the use environment, and have excellent durability and moisture resistance during repeated use, and have a residual potential and a ghost phenomenon. It is an object of the present invention to provide an electrophotographic photosensitive member for negative charging, in which image quality is hardly observed, and which has a good image quality, and a manufacturing method capable of stably supplying the electrophotographic photosensitive member.

[0026]

In order to solve the above-mentioned problems, the electrophotographic photoreceptor of the present invention comprises at least a conductive substrate, a photoconductive layer formed of a non-single crystal material having a silicon atom as a matrix, Upper blocking layer, surface layer to protect the surface,
An electrophotographic photosensitive member including: a) a non-single crystal material having a silicon atom and a carbon atom as a base material and containing an element of Group 13 of the periodic table, b) a dark state in an initial state before being exposed to light. Conductivity σ ₀ is 10
^-15 S / cm or more and 10 ^-10 S / cm or less, c) Light having a wavelength converted to 90% of the optical energy band gap at a intensity of 4 mW / cm2 for 120 minutes has a dark conductivity of σ ₁ And the rate of change in dark conductivity
Three conditions: (σ ₀ -σ ₁ ) / σ ₀ is 10% or more and 90% or less
It is characterized in that a film satisfying all of a) to c) is used as the upper blocking layer.

In addition, the rate of change (σ ₀ -σ ₁ ) / σ ₀ is 20
% To 80% is more preferable.

In addition, in the upper blocking layer, the range of the ratio C / (Si + C) of carbon atoms to the sum of silicon atoms (Si) and carbon atoms (C) is 0.05 ≦ C / (Si + C). It is more preferable that ≦ 0.6.

In addition, the content of the Group 13 element of the periodic table with respect to the sum of silicon atoms and carbon atoms in the upper blocking layer is more preferably 100 atom ppm or more and 30,000 atom ppm or less.

In addition, the thickness of the upper blocking layer is 0.01 μm.
More preferably, it is 1 μm or less.

In addition, it is more preferable that the upper blocking layer contains hydrogen atoms, and the concentration of hydrogen atoms in the film thickness direction gradually decreases toward the surface layer side.

In order to solve the above-mentioned problems, in the method for producing an electrophotographic photosensitive member of the present invention, a conductive substrate is placed in a depressurizable reaction container, plasma is generated by high frequency power, and the substrate is plasma-treated. Using a plasma processing apparatus for processing, at least a photoconductive layer having a silicon atom as a host, an upper blocking layer containing a Group 13 element having silicon atoms and carbon as a host, and a surface layer for protecting the surface are provided on at least the substrate. In the step of depositing to manufacture a photoreceptor, a high frequency power of 30 MHz or more and 250 MHz or less is used at least when the upper blocking layer is formed, and the dark conductivity σ ₀ of the upper blocking layer in the initial state before being exposed to light is 10 ^{−. 15} S / cm or more 10
^-10 S / cm or less and the darkness of the upper blocking layer after irradiation with light having a wavelength converted to 90% of the optical energy band gap of the upper blocking layer at an intensity of 4 mW / cm2 for 120 minutes. Rate of change of conductivity σ ₁ with respect to σ ₀
The feature is that (σ ₀ −σ ₁ ) / σ _{0 is set} to be 10% or more and 90% or less.

The rate of change (σ ₀ -σ ₁ ) / σ ₀ is 20%.
It is more preferably 80% or less.

In addition, it is more preferable to use high frequencies of at least two different frequencies when forming the upper blocking layer.

In addition, when the high frequencies of the two different frequencies are f1 and f2, the relationship between f1 and f2 is f
It is more preferable that 1> f2 and 0.5 <f2 / f1 ≦ 0.9.

In addition, when the high frequency powers of the two different frequencies are P1 and P2, respectively, the relationship between P1 and P2 is 0.1 ≦ P2 / (P1 + P2) ≦ 0.9. More preferable.

In addition, it is more preferable to apply the two high frequencies having different frequencies to the same electrode.

In addition, it is more preferable to increase the temperature of the conductive substrate when forming the upper blocking layer.

(Function) The present inventors investigated the relationship between the role of the upper blocking layer and the method of making it and the electrophotographic photosensitive member for negative charging under various conditions.

As a result, the conditions for forming the upper blocking layer, that is, the type of gas used, the flow rate and mixing ratio of the gas used, the pressure in the reaction vessel, the high frequency power and its frequency, the concentration of the Group 13 element of the periodic table, etc. By appropriately changing, the dark conductivity σ ₀ of the upper blocking layer immediately after the film deposition is within a predetermined range, and a slight change in the dark conductivity occurs when a predetermined light is applied. When the upper blocking layer is created, specifically, when the dark conductivity after specific light irradiation is σ ₁ , the rate of change of dark conductivity (σ ₀ -σ ₁ ) / σ ₀ is within a predetermined range. When it is set, both improvement of charging ability and suppression of uneven charging ability are prevented, image deletion is prevented, sensitivity is prevented from being reduced, minute cracks on the surface of the photoreceptor are suppressed, ghost phenomenon is suppressed, and other characteristics of the electrophotographic photoreceptor are suppressed. It was found that an improvement was seen.

The reason why the effect of the present invention is obtained is as follows.
Although not all have been clarified, the present inventors think as follows.

First, the features of the negative charging electrophotographic photosensitive member will be described. In the case of a negative charging electrophotographic photoreceptor, it is often technically difficult to prevent charge injection from the surface as compared with the case of positive charging. This is because, for example, in the case of an amorphous silicon carbide film formed to be suitable as a surface layer, negative charges can pass to some extent, but positive charges hardly flow. Therefore, if the positive charge can be sufficiently blocked by the surface layer,
It is thought that there are many cases where the negative charge cannot completely block. Here, when the characteristics of the surface layer are changed to the extent that electrons can be blocked by the surface layer, the positive charges that are generated by exposure and cancel the surface charges also become difficult to flow, and adverse effects such as an increase in residual potential occur. Is likely to occur. From this, in the case of the electrophotographic photoreceptor for negative charging, it is more desirable to provide the upper blocking layer made of a p-type semiconductor.

Conventionally, since attention has been paid only to the charging ability,
The main characteristic of the upper blocking layer is to use a p-type semiconductor, and much attention has not been paid to other characteristics. However, in recent years, the demand for copying machines has increased, and in the case of considering comprehensive improvement of photoreceptor characteristics, that is, compatibility between improvement of charging ability and suppression of uneven charging ability, improvement of sensitivity, improvement of ghost characteristics, cost reduction, etc., Improvement is needed.

In order to improve the upper blocking layer, the present inventors formed deposited films under various conditions and examined the characteristics of the films. Then, the film adjusted to cause a change in dark conductivity by a very small amount when irradiated with a specific light has extremely good uneven charging ability as compared with a film that does not substantially change, and the stopping power and sensitivity, It was found that there was no problem with the ghost characteristics at all and the balance was very good.

Specifically, the dark conductivity was measured using a film of a single composition corresponding to the upper blocking layer, and a photoreceptor having the film of that composition as the upper blocking layer was prepared to obtain various characteristics of the photoreceptor. The work of evaluating was repeated. Then, the dark conductivity (which is σ ₀ ) of the film in the initial state before being exposed to light is 1
It was found that it is necessary to be 0 ^-15 S / cm or more and 10 ^-10 S / cm or less. The dark conductivity in the initial state before shining the light here is the value when the dark conductivity is measured while keeping it out of the light, such as by putting it in a black paint box when taking it out from the reactor. Is shown. Even with room light, the exposure intensity and time must be within the range that does not change the characteristics. For example, in the case of indoor light, depending on the type of illumination (wavelength of light) and the like, in a fluorescent lamp and an average working environment of about 500 lx, it is desirable that it is within 5 minutes as a guide. If it is exposed to light such as room light for a long time, the change in dark conductivity may not be accurately measured, but the temperature is raised to about 150 ° C in vacuum for about 10 minutes. By holding it, it is possible to restore the dark conductivity of the initial state before the light is applied. When accidentally exposed to light for a long time, the temperature may be raised as described above to recover the same state as the initial state.

It is considered that this σ ₀ represents the conductivity of holes in the film doped with the Group 13 element. This σ0
Is smaller than a certain degree, specifically smaller than 10 ⁻¹⁵ S / cm, there is a possibility that holes generated by light may be prevented from flowing to the surface side. When it is 10 ⁻¹⁵ S / cm or more, it is possible to prevent the increase of the residual potential, the suppression of the sensitivity sag, the decrease of the shift, and the prevention of the ghost.
More preferably 10 ^-14 S / cm or more, optimally 10 ^-13 S
/ cm or more is desirable. On the other hand, when σ ₀ is larger than 10 ^-10 S / cm, there are two types depending on the addition amount of Group 13 of the periodic table. First, a film heavily doped with a Group 13 element should have a stronger p-type, so it has sufficient electron blocking ability and good chargeability, but carrier cross-flow tends to occur easily. In some cases, image deletion may occur. Also, when the doping amount is small,
It is considered that the p-type is weak and the hole concentration is low, and in such a case that σ0 is larger than 10 ⁻¹⁰ S / cm, there is a high possibility that the electron blocking ability is insufficient. In any case, the dark conductivity is preferably 10 ^-10 S / cm or less, more preferably 10 ^-11 S / cm or less.

In addition, the change in dark conductivity upon irradiation with light having a wavelength converted to about 90% of the optical energy band gap of the upper blocking layer is a well-balanced result as described above.
It was found that there is a strong correlation with (combining good film characteristics and reduction of unevenness). The cause is Staebler Wronski
Expected to be associated with similar structural changes to effects, but details are unknown. According to this prediction, it is considered that the recombination of bonds is induced by the photoexcitation of electrons between the levels just near the band tail, and the level density near the band tail changes. It is considered that such a change has a great influence on the drum characteristics, and that by improving the degree of the change within an appropriate range, it is possible to improve the characteristics and improve the unevenness.

Specifically, the light having a wavelength converted into just 90% of the optical energy gap has an intensity of 4 mW / c.
Change in dark conductivity after irradiation for 120 minutes at m ² (σ ₀ -σ ₁ )
It is preferable that / σ ₀ is 10% or more and 90% or less.
For films smaller than 10%, that is, almost unchanged,
Characteristic unevenness may occur. On the other hand, if it exceeds 90%, electrophotographic characteristics may be affected.

The inventors of the present invention consider the following as to the reason why the electrophotographic photosensitive member is more advantageous in the case where a slight change in the dark conductivity occurs.

In the investigation of the upper blocking layer, the present inventors deposited a thin film of a single composition on glass, and applied 4 mW / cm
Bright conductivity was measured using a He-Ne laser of ² .
Then, it was found that the light irradiation in the measurement of the bright conductivity changes the dark conductivity of the film, and the change of the dark conductivity varies depending on the film. Furthermore, a study was conducted by paying attention to the change in dark conductivity due to this light irradiation. As compared with a film that does not cause a substantial change in conductivity, a film that causes a slight change in dark conductivity is found in the axial and circumferential directions. It was discovered that the characteristic unevenness was extremely small in both directions. The wavelength of this He-Ne laser corresponds to exactly 90% of the Egopt of the film, and it is clear that the film with different Egopt shows the same behavior when the wavelength corresponding to 90% is also used. Became.

From these results, it can be seen that the film, which hardly changes due to light irradiation, has an extremely excellent photoconductive property in part, but is also affected by gas distribution unevenness, temperature unevenness, power unevenness, etc., which are considered to be the origin of the characteristic unevenness. I expected that it would be easy and would result in a large difference in characteristics. On the other hand, in a film that causes a slight amount of change due to light irradiation,
It is considered that the characteristic unevenness is less likely to occur because the effect of the unevenness of the deposition conditions described above is not easily received for some reason. The reason why it became less susceptible to the unevenness of the deposition conditions was that some defects (dangling bonds), which are considered to be one of the origins of the change due to light irradiation, existed from the beginning, and the defects were caused by the unevenness of the deposition conditions. Since the amount of change is limited, it is thought that the unevenness of the defect density is reduced, and as a result, the unevenness of the photoconductive characteristics is reduced, but the details are unknown. Results obtained experimentally, 4
10 when irradiated for 120 minutes at an intensity of mW / cm ^2.
% Or more, the dark conductivity is preferably changed, and more preferably 20% or more.

In addition, the light irradiation amount accumulated by irradiating such a laser beam for 120 minutes is about 5 million sheets in terms of static elimination light, which corresponds to about the life of the a-Si photosensitive member. Further, if (σ ₀ -σ ₁ ) / σ ₀ is 90%, it means that σ ₁ is 1/10 of σ ₀ , and the dark conductivity changes by one digit depending on the number of life sheets. The impact on Therefore, when a change in the characteristics of the photoconductor was actually examined by a durability test, it was found that if the photoconductor has an upper blocking layer with a conductivity change rate of 90% or less,
No significant changes over time, which could be attributed to the upper blocking layer, were observed. On the other hand, if it exceeds 90%, deterioration of characteristics due to durability, specifically, deterioration of charging ability, increase of dark decay, increase of ghost potential, deterioration of sensitivity, etc. may be observed. Further, not only with time, but also with respect to the initial characteristics, the electrophotographic characteristics, especially the ghost characteristics were remarkably different in the photoconductor in which the film having the conductivity change rate of more than 90% was used as the upper blocking layer. It is thought that this is related to the defect level (dangling bond) density, which is considered to be one of the origins of the change in dark conductivity before and after light irradiation, but details are unknown. From the above, it was found that it is desirable that the rate of change in dark conductivity is 90% or less, and more preferably 80% or less.

In order to adjust the dark conductivity in the initial stage and the rate of change in dark conductivity due to light irradiation, after the composition ratio of the base silicon atom and carbon atom is appropriately determined,
Further, it can be controlled by appropriately adding the content of the Group 13 element of the periodic table which functions as a dopant.

Specifically, the range of the ratio C / (Si + C) of carbon atoms to the sum of silicon atoms and carbon atoms is 0.05 ≦.
It is desirable that C / (Si + C) ≦ 0.6. By setting the film thickness in this range to form the film, it is possible to obtain a film having a high stopping power and excellent electrophotographic characteristics. When the carbon content is higher than the above range, the residual potential is increased and the conductivity type controllability is deteriorated. Further, if the carbon content is further reduced, the dark resistance may be lowered and the stopping power may be lowered, so that caution is required.

The specific content of the Group 13 element is appropriately determined as desired so that the object of the present invention can be effectively achieved, but preferably the concentration in the film is based on silicon atoms. It may be introduced so as to be 100 atom ppm or more and 30,000 atom ppm or less. If it is less than 100 atom ppm, sufficient stopping power for electrons may not be obtained. From this point of view, it is more preferably 500 atom ppm or more. On the other hand, if it exceeds 30,000 atoms ppm, the effect of improving uneven charging ability may be reduced. In order to obtain the improvement effect to the maximum, it is more preferably 10,000 atom ppm or less.

Furthermore, as described above, when the plasma CVD method using a high frequency in the VHF band is used, the initial dark conductivity defined by the present invention and the rate of change in dark conductivity due to light irradiation are appropriate. It is more preferable to set it in accordance with the above because the characteristics can be made better and the deposition rate can be made faster than in the case of using a high frequency in the RF band. As mentioned above, there are many unclear points about this cause, but not all are known,
Probably, the difference in the energy of the active species in the plasma is responsible for the difference in the film properties.

As described above, when the VHF band frequency is used, the deposited film can be formed with high quality and at high speed, but the quality of the deposited film may vary due to the influence of the standing wave. . Therefore, this can be improved by superimposing at least two high-frequency waves in the VHF band and applying them to the electrodes. In principle, by superimposing two different high frequencies, one part of the standing wave has the amplitude of the standing wave at one frequency, and the other part has the amplitude of the standing wave. Because, it is considered. However, it goes without saying that this is a very simple model, and in reality complicated phenomena occur. For example, there are factors such as plasma conditions, electromagnetic wave attenuation, and reflection on various reflecting surfaces. Therefore, this suppression effect cannot always be obtained only by superposing high-frequency power of an arbitrary frequency at an arbitrary ratio. In other words, when the standing wave suppression effect is prominent, it is optimal when high frequencies in a constant frequency range are combined at a constant power value ratio. Particularly, the first high frequency and the second high frequency are of high quality. It is the frequency range in which a high deposition rate can be expected, and the frequency range in which the same active species can be generated together, and it is most desirable to appropriately set the power balance between them.

Specifically, it is preferable in terms of film quality and deposition rate that the lower limit of the desirable frequencies of the two high frequency powers is 30 MHz or more, more preferably 50 MHz or more. On the other hand, the upper limit is 25
It is preferable that the frequency is 0 MHz or less, since there are few restrictions on the device. That is, as the frequency increases, some of the inductance component and the capacitance component have large impedances, which often increases the restrictions on the device. From this point of view, 250M
It is preferably Hz or less.

In addition, when two electric powers are superposed on the same electrode, it may be difficult to obtain the effect by using a frequency higher than 250 MHz. That is, when a frequency higher than 250 MHz is used, the attenuation in the traveling direction of the electric power becomes remarkable, and the deviation of the attenuation rate from the high-frequency electric power of a different frequency becomes remarkable, so that a sufficient equalizing effect cannot be obtained. I will end up. Therefore, when the frequency is 250 MHz or less, the superimposing effect can be effectively obtained, which is preferable.

Further, it has been found that the ratio f2 / f1 between the frequency f1 of the first high frequency wave and the frequency f2 of the second high frequency wave is more than 0.5 and most preferably 0.9 or less. For example, f1
If f2 is different by one digit or more, the way of decomposing the raw material gas may be changed in some cases, and the type and ratio of the generated active species may be different. For this reason, even if the electric field strength is made uniform, active species having a type and a ratio corresponding to the frequency are generated in the antinode of the first high-frequency standing wave, and the second high-frequency standing wave is generated. There is a case where active species having a different kind and ratio from the antinode portion of the first high-frequency standing wave are generated in the antinode portion of. As a result, a spatial distribution may occur in the types and ratios of the active species, and in the worst case, the vacuum processing characteristics may become non-uniform. By maintaining the relationship of 0.5 <f2 / f1, it is possible to reduce the difference in the type and ratio of the generated active species due to the difference in frequency.
It is considered to be more preferable. Further, if f1 and f2 are too close to each other, the node position and antinode position of each standing wave are close to each other, so that a sufficient electric field standing wave suppression effect cannot be obtained.
It is considered desirable to maintain the relationship of f1 ≦ 0.9.

Regarding the range of the ratio of the power values of the two high frequencies, if the power value of the first high frequency is P1 and the power value of the second high frequency is P2, the total power value of the two high frequencies (P
The value of P2 with respect to (1 + P2) is preferably 0.1 or more and 0.9 or less. That is, when the ratio of P2 becomes smaller, the case of only P1 approaches, and the standing wave suppressing effect becomes smaller. Conversely, P
If the ratio of 2 becomes too large, it becomes similar to the case of P2 alone, and the effect becomes small. From experimental facts, at least one high frequency power is 1 for two total powers.
It was found that the effect of suppressing standing waves can be remarkably obtained when the content is 0% or more. Further, it has been further clarified from experiments that it is most desirable to set P2 / (P1 + P2) to 0.2 or more and 0.7 or less, where P1 is the power of the higher frequency.

Image smearing is a phenomenon in which photo-generated carriers generated by exposure move laterally in the process of moving from the photoconductive layer to the surface layer and the image is blurred. In the upper blocking layer of the present invention, the initial dark conductivity and the film thickness are appropriately determined, and it is considered that the situation in which the carriers cause the lateral flow does not occur. From the above factors, it is considered that the image blur caused by the lateral flow of the carrier, that is, the so-called image deletion phenomenon is less likely to occur.

Further, it is considered that the minute cracks generated on the surface of the photoconductor are mainly caused by a decrease in adhesion in the vicinity of the interface between the photoconductive layer and the upper blocking layer or between the upper blocking layer and the surface layer, or distortion due to stress. In the upper blocking layer, the group 13 element of the periodic table is added in a considerably high concentration in order to block negative carriers, but if it is not added appropriately, the stress of the film may be increased in some cases, and the amount may be small. It could cause cracks. In the upper blocking layer of the present invention,
The Group 13 element of the periodic table is added so that the electrical conductivity falls within an appropriate range, but this range seems to be suitable for preventing an increase in stress difference. In addition, it was found that the amount of hydrogen atoms contained in the upper blocking layer is greatly related to the stress. In the upper blocking layer of the present invention, it is preferable that the concentration of hydrogen atoms in the film thickness direction is gradually reduced toward the surface layer side. By doing so, the stress is relieved, and minute cracks and the like are extremely unlikely to occur, which is more preferable.
In this way, the hydrogen atom content can be gradually reduced toward the surface layer side by increasing the temperature of the substrate during film deposition with time. The actual temperature cannot be decided unconditionally because it depends on the formation temperature of the photoconductive layer and the surface layer, but taking these into consideration, the temperature of the substrate should be as high as possible toward the surface layer side. It is more preferable to set the temperature of.

As a result of the above improvements, the present invention makes it possible to improve the charging ability (blocking ability) of the electrophotographic photosensitive member and suppress the uneven charging ability at a high level, and at the same time, prevents the image deletion and the electrophotographic photosensitive member. Image quality is dramatically improved by reducing minute cracks on the surface, and does not change over time.
By solving all of the above-mentioned problems in the prior art, a negative charging electrophotographic photoreceptor having extremely excellent electrical and optical characteristics, image quality, durability and environmental resistance is provided, and reproducibility thereof is provided. Provided is a manufacturing method that can be easily obtained.

[0065]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a negative charging electrophotographic photosensitive member of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic constitutional view for explaining an example of a preferable layer constitution of an electrophotographic photosensitive member produced by the manufacturing method of the present invention.

The electrophotographic photosensitive member shown in FIG.
A lower blocking layer 102, a silicon-based photoconductive layer 103, and an upper blocking layer 1 of silicon and carbon.
04 and the surface layer 105 are provided in this order.

The upper blocking layer 104 is not necessarily required to have photoconductivity, and on the other hand, it is necessary to have a function which cannot be realized by the photoconductive layer 103. In order to realize that function, the photoconductive layer is required. It goes without saying that a creation method that is clearly different from 103 is used. On the other hand, the surface layer 105
Compared with, the hardness and durability required for this are not necessarily required, and on the other hand, a function that cannot be realized by the surface layer 105 is required, and in order to realize that function, It goes without saying that a manufacturing method distinctly different from that of the surface layer 105 is adopted.

FIG. 1B is a schematic configuration diagram for explaining another layer configuration. In the electrophotographic photosensitive member shown in FIG. 1 (a), the photoconductive layer 103 has a single layer structure, while in FIG.
Differs in that the photoconductive layer is divided into two regions. For example, a high-quality film having high photocarrier generation efficiency and few defects is used for the upper region 107, and a film specialized for improving carrier mobility is used for the lower region 106, thereby improving the degree of freedom in layer design. It becomes possible.

Further, in any of FIGS. 1 (a) and 1 (b),
The lower blocking layer 102 is not an essential component and may be omitted if necessary. In addition, the interface of each layer does not necessarily have to be a sharp and clear interface. Especially when using a laser exposure that easily causes light interference, change the composition smoothly at the interface so as not to create a clear interface. It is preferable to

<Substrate> The substrate used in the present invention may be conductive or electrically insulating. As the conductive substrate, Al, Cr, Mo, Au, In, Nb, Te,
Examples thereof include metals such as V, Ti, Pt, Pd and Fe, and alloys thereof such as stainless steel.

A film or sheet of synthetic resin such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polystyrene or polyamide as an electrically insulating material,
Examples thereof include glass and ceramics. In the present invention, at least the surface of the electrically insulating substrate on which the photosensitive layer is formed can be subjected to a conductive treatment to be used as the substrate.

The shape of the substrate 101 used in the present invention may be a cylindrical surface having a smooth surface or a minute uneven surface or an endless belt shape, and the thickness thereof is the same as that of an electrophotographic photosensitive member as desired. It is appropriately determined so that it can be formed. When flexibility as an electrophotographic photoreceptor is required, it can be made as thin as possible within a range in which the function of the base 101 can be sufficiently exhibited. However, the substrate 101 is usually 10 μm or more in terms of manufacturing and handling, mechanical strength and the like.

<Photoconductive Layer> In the present invention, the photoconductive layer 1
No. 03 is formed by the vacuum deposition film forming method, by appropriately setting the numerical conditions of film forming parameters so that desired characteristics can be obtained. Specifically, the glow discharge method is preferable because it is relatively easy to control the conditions for producing a photoconductor having desired characteristics, and in particular, the high frequency glow discharge method using a power supply frequency in the VHF band is preferable. It is suitable.

In order to form the photoconductive layer 103 by the glow discharge method, basically, a silicon-containing gas capable of supplying silicon atoms (Si) is introduced in a desired gas state into a reaction vessel whose inside can be decompressed. Then, glow discharge is caused to occur in the reaction vessel, and a layer made of a-Si: H, X may be formed on a predetermined substrate 101 installed in a predetermined position in advance.

In the present invention, when the photoconductive layer 103 is formed, a gas for supplying hydrogen atoms (H) and / or a gas for supplying halogen atoms (X) is introduced, so that the photoconductive layer 103 can be formed.
A hydrogen atom and / or a halogen atom can be contained therein. This compensates the dangling bonds of silicon atoms,
It is more preferable because improvement of layer quality, especially improvement of photoconductivity and charge retention property can be expected.

The substances which can be used as the silicon-containing gas in the present invention include SiH ₄ , Si ₂ H ₆ and Si.
Gases of ₃ H ₈ , Si ₄ H _10, etc., or gasifiable silicon hydrides (silanes) are mentioned as being effectively used, and further, they are easy to handle during layer formation and have good Si supply efficiency. In view of the above, SiH ₄ and Si ₂ H ₆ are preferable.

Then, for the purpose of structurally introducing hydrogen atoms or halogen atoms into the photoconductive layer 103 to be formed and facilitating the control of the introduction ratio of these terminal elements, H ₂ or H ₂ is added to these gases. A desired amount of a gaseous or gasifiable halogen compound such as a silicon compound gas containing a hydrogen atom, a halogen gas, a halide, an interhalogen compound containing a halogen, a silane derivative substituted with a halogen, or the like may be mixed. . Further, each gas may be mixed not only with one kind but also with plural kinds at a predetermined mixing ratio.

To control the amount of hydrogen atoms and / or halogen atoms contained in the photoconductive layer 103, for example, the temperature of the substrate 101, the raw material used for containing hydrogen atoms and / or halogen atoms The amount to be introduced into the reaction container, the discharge power, and the like may be controlled.

In addition to these gases, a rare gas may be used as a diluting gas, and may be used alone or as a mixture with another diluting gas.

In the present invention, it is possible to introduce conductivity controlling atoms into the photoconductive layer 103, and the atoms may be further distributed.

Examples of the atoms that control the conductivity include so-called impurities in the semiconductor field.
An atom belonging to Group 13 of the Periodic Table (hereinafter abbreviated as “Group 13 atom”) that gives p-type conductivity or / and an atom belonging to Group 15 of the Periodic Table that gives n-type conductivity (hereinafter “15th group”).
(Abbreviated as “group atom”) can be used.

Specific examples of the group 13 atom include boron.
(B), aluminum (Al), gallium (Ga), indium
There are (In), thallium (Tl) and the like, and B, Al and Ga are particularly preferable.

As the group 15 atom, specifically, nitrogen
(N), phosphorus (P), arsenic (As), antimony (Sb), lead (Pb)
Etc., and P and As are particularly preferable.

Controlling conductivity contained in photoconductive layer 103
As for the content of atoms,
Adjust by adding a small amount of gas containing. Specifically,
B ₂H₆If you want to add boron using gas, trace amount
B for easier adjustment₂H₆Gas H₂And He
It may be added after diluting it. Specific content and
Therefore, it is preferably 5 × 10 5 for Si atom.^-3~ 50
Atom ppm, more preferably 1 × 10^-2~ 30 atom ppm,
Optimal 5 × 10^-2Maximum content between ~ 20 atom ppm
It is desirable that the minimum content and the minimum content be appropriately selected and contained.

As a raw material for introducing a Group 13 atom, it is desirable to employ a gaseous substance at room temperature and normal pressure or a substance which can be easily gasified under at least the layer forming conditions.

For example, as a raw material for introducing a Group 13 atom, specifically, for introducing a boron atom, B ₂ H ₆ and B _{4 are used.}
Examples thereof include boron hydrides such as H ₁₀ , B ₅ H ₉ , B ₅ H ₁₁ , B ₆ H ₁₀ , B ₆ H ₁₂ , and B ₆ H ₁₄ , and boron halides such as BF ₃ , BCl ₃ and BBr _3. . In addition, AlCl ₃ , GaCl ₃ , Ga
(CH ₃ ) ₃ , InCl ₃ , TlCl _{3 and the} like can also be mentioned.

The same applies to the raw material for introducing the Group 15 atom.
It is desirable that it is in a gaseous state or that can be easily gasified.

For example, as a raw material for introducing a Group 15 atom, specifically, for introducing a phosphorus atom, PH ₃ , P ₂ H
Phosphorus hydride such as ₄ , PF ₃ , PF ₅ , PCl ₃ , PCl ₅ , P
Examples thereof include phosphorus halides such as Br ₃ , PBr ₅ , and PI ₃ . In addition, AsH ₃ , AsF ₃ , AsCl ₃ , AsBr ₃ , As
F ₅ , SbH ₃ , SbF ₃ , SbF ₅ , SbCl ₃ , SbCl ₅ , Bi
H ₃ , BiCl ₃ , BiBr _{3 and the} like can also be mentioned as effective starting materials for introducing a Group 15 atom.

Further, in the present invention, the photoconductive layer 103
In order to contain carbon atoms and / or oxygen atoms and / or nitrogen atoms in the raw material gas, a carbon-containing gas, an oxygen-containing gas and a nitrogen-containing gas may be appropriately added. The content of carbon atoms and / or oxygen atoms / and / or nitrogen atoms is preferably 1 × 10 ⁻⁵ to 10 atom%, more preferably 1 × 10 ^{5 with} respect to the sum of silicon atoms, carbon atoms, oxygen atoms and nitrogen atoms. ^-4 to 8 atom%, optimally 1 x 10 ^{-3 to} 5 atom%
Is desirable. The carbon atoms and / or oxygen atoms and / or nitrogen atoms may be uniformly contained in the photoconductive layer, or may have a non-uniform distribution such that the content changes in the layer thickness direction of the photoconductive layer. There may be a part that has.

In the present invention, the layer thickness of the photoconductive layer 103 is appropriately determined as desired in view of obtaining desired electrophotographic characteristics and economic effects, and is preferably 10
˜50 μm, more preferably 15 to 45 μm, most preferably 20 to 40 μm. Layer thickness is 10 μm
When the thickness is thinner, the electrophotographic characteristics such as charging ability and sensitivity are not practically sufficient, and when the thickness is more than 50 μm, the production time of the photoconductive layer is long and the production cost is high.

In order to achieve the object of the present invention and form the photoconductive layer 103 having desired film characteristics, the flow rate of the gas for supplying Si, the mixing ratio with the diluting gas when diluting, and the inside of the reaction vessel are used. It is necessary to properly set the gas pressure, the discharge power and the substrate temperature.

Similarly, the gas pressure in the reaction vessel is also appropriately selected in accordance with the layer design, but in the usual case, it is 1 × 1.
0 ^-2 to 1 x 10 ² Pa, preferably 5 x 10 ^{-2 to} 5 x 10
¹ Pa, optimally 1 × 10 ⁻¹ to 2 × 10 ¹ Pa is preferable.

Similarly, the optimum range of discharge power is also selected according to the layer design, but the ratio P of the discharge power P (unit: W) and the flow rate F (unit: ml / min (normal)) of the silicon-containing gas is P. / F is optimally 2 to 30, preferably 5 to 20,
Optimally, it is desirable to set it in the range of 8 to 15.

Further, the temperature of the substrate 101 is appropriately selected according to the layer design, but in the usual case, it is preferably 150 to 350 ° C., more preferably 170 to 3 ° C.
30 ° C., optimally 190 to 310 ° C. is desirable.

In the present invention, the above-mentioned ranges are mentioned as desirable numerical ranges of the gas pressure, the discharge power and the substrate temperature for forming the photoconductive layer, but the conditions are not usually determined independently. Instead, it is desirable to determine the optimum value based on mutual and organic relationships to form a light receiving member having the desired properties.

<Upper Blocking Layer> The upper blocking layer has a function of preventing charges from being injected from the free surface side to the photoconductive layer side when the photoreceptor is charged on its free surface. . In order to impart such a function, the upper blocking layer is required to have a certain level of high resistance, and in order to realize it, at the same time as adding a small amount of carbon to the a-Si film to increase the resistance, at the same time, the periodic table group 13 It is necessary to set the resistance to holes in an appropriate range by adding. In addition, in the present invention, paying attention to the change in dark conductivity upon irradiation with light, the amount of carbon, the addition amount of the Group 13 element, and the bond are adjusted so that a slight change in dark conductivity occurs in a desired range. It is necessary to properly control the state.

The substances which can be used as the silicon-containing gas in the present invention include SiH ₄ , Si ₂ H ₆ and Si.
Silicon hydrides (silanes) such as ₃ H ₈ and Si ₄ H _{10 and} silane derivatives substituted with halogen such as SiF ₄ can be cited as effective ones. SiH ₄ is easy to handle at the time of production and has high supply efficiency.
Are most preferred.

As a substance which can be a gas for supplying carbon,
A hydrocarbon in a gas state such as CH ₄ , C ₂ H ₂ , C ₂ H ₆ , C ₃ H ₈ and C ₄ H ₁₀ or a gasifiable hydrocarbon can be mentioned as being effectively used, and further has good film properties. CH ₄ because it is easy to handle, easy to handle when creating layers, and difficult to polymerize.
Is most preferred.

If necessary, a suitable diluent gas may be used for dilution. As a specific diluent gas, hydrogen,
Noble gases such as He, Ne, Ar and Kr are suitable, and several kinds of these may be mixed and used.

The composition of the upper blocking layer 104, that is, the ratio of carbon atoms to the sum of silicon atoms and carbon atoms C / (Si + C)
It is desirable that the range of (2) has a high stopping power and is good with respect to other electrophotographic characteristics. When carbon is added to the a-Si film, it is considered that the defect level density is likely to increase when light is applied. That is, assuming that the initial defect level density is N ₀ and the number of photoinduced defects is ΔN, ΔN / N ₀ is the increase rate of the defect level density. From the experimental fact, it is thought that this increase rate ΔN / N ₀ will increase dramatically when only a small amount of carbon is added, and then it will start to decrease, but it is difficult to measure ΔN accurately, and it is currently known in detail. Absent. It is considered that the range of the present application is preferable after turning to this decrease, and the range in which valence electron control is possible is preferable. Specifically, it has been experimentally clarified that the range of 0.05 ≦ C / (Si + C) ≦ 0.6 is desirable. When the carbon content is higher than the above range, the controllability of valence electrons is deteriorated, and adverse effects such as increase in residual potential may occur. Further, if the carbon content is further reduced, the increase rate of the defect level density may increase and the change in dark conductivity due to light irradiation may increase, or the dark resistance may decrease and the stopping power may decrease. Be careful, because it is possible.
In order to achieve such a composition, when the above-mentioned gas is used as a raw material gas, its flow rate and mixing ratio,
The dilution rate, the power per unit gas flow rate, etc. may be changed. However, since plasma CVD is generally sensitive to equipment, it is not certain that the composition can be made into any composition depending on the equipment configuration and conditions, and optical measurement (infrared absorption, visible light ~ Measurement of absorption coefficient of ultraviolet light)
The composition is predicted by using, for example, secondary ion mass spectrometry (S
It is desirable to design a desired composition by changing the conditions while quantifying using IMS).

In order to effectively prevent the injection,
At the time of forming the upper blocking layer, it is desirable to add a gas containing atoms that control conductivity (atoms belonging to Group 13 of the periodic table).

The conductivity-controlling atoms contained in the layer are uniformly distributed in the layer, so that a constant amount may be supplied at the time of forming the layer, or the atoms may be non-uniformly distributed. The flow rate of the gas added for this purpose may be changed with time. However, in any case, care should be taken to make the gas distribution uniform at the time of preparation, in order to make the content evenly distributed in the direction parallel to the surface.

In the present invention, in order to contain the atoms for controlling the conductivity in the charge injection blocking layer, the above-mentioned first method is used.
It is realized by adding an appropriate amount of a gas containing a Group 3 element to a raw material gas consisting of a silicon-containing gas, a carbon-containing gas, and / or a diluent gas such as a rare gas / hydrogen. Concrete first
The content of the Group 3 element is appropriately determined as desired so that the object of the present invention can be effectively achieved, but preferably, the concentration in the film is 100 atom pp to silicon atom.
It suffices to introduce them so that the number of atoms is m or more and 30,000 atoms ppm or less. If it is less than 100 atom ppm, sufficient stopping power for electrons may not be obtained. From this point of view, it is more preferably 500 atom ppm or more. Also, 30000
If it exceeds the atomic ppm, the effect of improving uneven charging ability may be reduced. 10000 for maximum improvement
More preferably, the atomic ppm or less. Further, in order to increase the ease of adjusting the amount of addition, it may be added together with a diluent gas as appropriate. Hydrogen gas or a rare gas is suitable as the diluent gas for the Group 13 element-containing gas.

In the upper blocking layer of the present invention, the dark conductivity σ ₀ before being exposed to light is 10 ⁻¹⁵ S / cm or more and 10 ^−10.
It is necessary to be S / cm or less. This dark conductivity is
For example, it can be controlled by changing the ratio of silicon atoms to carbon atoms and the amount of Group 13 element as described above. On the other hand, the dark conductivity may be measured as follows. First, a thin film having a single composition is formed on glass by using the method for forming the film used for the upper blocking layer. It is preferable to use Na-free glass, for example, Corning # 7059 may be used. Using this substrate, a film equivalent to the upper blocking layer is deposited by about 1 μm. Next, after taking out the sample on the glass, a comb-shaped electrode mask is brought into close contact with it and then 1000Å of Cr is deposited by a vacuum evaporation method to form a comb-shaped electrode. A voltage of several tens V to 100 V is applied to this comb-shaped electrode, the flowing current is measured using a pA meter (for example, 4140B manufactured by HP), and the dark conductivity σ ₀ is calculated from these values. At this time, it is most preferable to shorten the exposure time to the light as much as possible in order to reduce the measurement error after the light irradiation described later.
For example, in the case of indoor light, depending on the type of illumination (wavelength of light) and the like, in a fluorescent lamp and an average working environment of about 500 lx, it is desirable that it is within 5 minutes as a guide. If it is exposed to light such as room light for a long time, the change in dark conductivity may not be accurately measured.
By raising the temperature to about 150 ° C. in a vacuum and holding it for about 10 minutes, it is possible to restore the dark conductivity of the initial state before applying light. When accidentally exposed to light for a long time, the temperature may be raised as described above to recover the same state as the initial state.

Next, using a sample on glass prepared under the same conditions, optical absorption spectrum measurement (visible light to UV) is performed, and the optical energy band gap is measured from the relationship between the absorption coefficient and the wavelength. If the absorption coefficient of the film at each frequency is α (ν), the light energy is hν, and B is a constant, α (ν) = B (hν-Egopt) ² / hν (1) (α (ν) ・ hν) ^1/2 = B ^1/2 · (hν-Egopt) (2) The absorption coefficient α is plotted on the graph (so-called Tauc
Plot), the optical energy bandgap Egopt from the value of the intercept asymptotically obtained from the linear relationship of equation (2).
Is required.

Next, 90% of hν corresponding to this Egopt
The sample of the upper blocking layer glass on which the above comb-shaped electrodes are vapor-deposited is irradiated with light of hν ′ corresponding to the above condition at 4 mW / cm ² for 120 minutes. Such monochromatic light is obtained by spectrally splitting halogen light using, for example, a monochromator. The intensity of the dispersed light may be adjusted by using an optical power meter (for example, Q8221 manufactured by Advantest Corporation), and the sample may be irradiated with the light.

After irradiating light of such a wavelength for a fixed amount of time for a fixed time, the dark conductivity (denoted by σ ₁ ) is measured again.
The binding state changes when exposed to light, and the dark conductivity is σ
Decrease compared to ₀ . At that time, the rate of change of dark conductivity (σ _0-
It is preferable that σ ₁ ) / σ ₀ is 10% or more and 90% or less. When it is less than 10%, unevenness in characteristics may occur easily, so 10% or more is desirable, and more preferably 20% or more is more preferable because the effect of suppressing characteristic unevenness is more likely to be obtained. On the other hand, when it is more than 90%, the change with time may become remarkable and a problem may occur in the image quality in some cases, or the ghost characteristics may be deteriorated because the defect density increases too much. Therefore, 90% or less is desirable. More preferably, the content of 80% or less is more preferable because a change in characteristics with time is not substantially observed and ghost characteristics are not deteriorated. The rate of change of the dark conductivity is, for example, the ratio of silicon atoms to carbon atoms or the thirteenth value as described above.
It may be controlled by changing the amount of the group element.

In the present invention, the layer thickness of the charge injection blocking layer is preferably 0.01 to 1.0 μm, more preferably 0.0 from the viewpoint of obtaining desired electrophotographic characteristics and economical effects.
It is desirable that the thickness is 3 to 0.7 μm, most preferably 0.05 to 0.5 μm. If the layer thickness is less than 0.01 μm, the charge injection blocking ability from the surface is insufficient and sufficient charging ability cannot be obtained, and if it is more than 1.0 μm, the efficiency of hole ejection from the photoconductive layer becomes poor. Electrophotographic characteristics such as sensitivity, shift, and ghost are degraded. In addition, the manufacturing time is extended, which causes an increase in manufacturing cost.

To form the upper blocking layer in the present invention, a vacuum deposition method similar to the method for forming the photoconductive layer described above, that is, a plasma CVD method using high frequency is adopted. At that time, in order to maximize the effect of the present invention, it is most preferable to set the high frequency used for the discharge to the frequency in the VHF band. In addition to the deposition conditions described so far, it is necessary to appropriately set the pressure in the reaction container, the temperature of the substrate, and the like.

The gas pressure in the reaction vessel depends on the layer design.
The optimum range is selected as appropriate, but high frequencies in the VHF band are used.
1 x 10 when used^-2~ 5 x 10²Pa, preferably 5 ×
10 ^-2~ 5 x 10¹Pa, optimally 1 × 10^-1~ 2 x 10
¹It is preferably Pa.

The optimum range of discharge power is also appropriately selected according to the layer design. The ratio of the discharge power to the total flow rate of the gas for supplying Si and the gas for supplying C is VH.
When using a high frequency in the F band, 1 to 40, preferably 3 to 3
It is desirable to set 0, optimally 5 to 20.

Further, the temperature of the substrate 101 is appropriately selected depending on the layer design, but in the usual case, it is preferably 150 to 350 ° C., more preferably 170 to 3 ° C.
30 ° C., optimally 190 to 310 ° C. is desirable.

In particular, in the present invention, the temperature is changed at the time of forming the upper blocking layer so that the amount of hydrogen atoms contained in the upper blocking layer is gradually reduced toward the surface side. It is most desirable because it is unlikely to occur and an effect of suppressing cracks and peeling can be expected. The hydrogen atom content can be reduced on the surface side by gradually increasing the temperature toward the surface side. The temperature difference between the start time and the end time of the upper blocking layer causes a stress difference on the contrary even if there is too much temperature difference, and if the temperature difference is too small, no effect is seen. Specifically, the difference in substrate temperature between the start and the end of forming the upper blocking layer may be set to about 10 ° C. to 60 ° C., and it is desirable to change the temperature gently from the start to the end.

In the present invention, in order to form the upper blocking layer, the mixing ratio of the silicon-containing gas and the carbon-containing gas, the added amount of the gas containing the conductivity control substance, the gas pressure in the reaction vessel, the discharge power, the substrate Although the desirable numerical ranges of temperature include the ranges set forth above, these layer-making factors are usually not independently determined separately, but rather in a mutual and organic manner to form a top blocking layer having the desired properties. It is desirable to determine the optimum value for each layer fabrication factor based on relevance.

<Surface Layer> In the present invention, an amorphous silicon-based surface layer 105 may be further formed on the photoconductive layer 103 and the upper blocking layer 104 formed on the substrate 101 as described above. desirable. This surface layer 10
No. 5 is provided to achieve the object of the present invention mainly in moisture resistance, continuous repeated use characteristics, electrical pressure resistance, use environment characteristics, and durability.

The surface layer 105 includes, for example, amorphous silicon containing hydrogen atoms (H) and / or halogen atoms (X) and further containing carbon atoms (hereinafter referred to as “a-SiC: H, X”).
It is suitable to use). Alternatively, an amorphous substance containing a silicon atom and a hydrogen atom and / or a halogen atom and containing at least one element of a carbon atom, a nitrogen atom and an oxygen atom (for example, a-SiNO: H, X) can also be used. . Non-single crystal carbon (a-C: H, mainly containing carbon atoms,
X) is also preferably used.

In the present invention, in order to effectively achieve the object, the surface layer 105 is formed by a vacuum deposition film forming method by appropriately setting numerical conditions of film forming parameters so that desired characteristics can be obtained. To be done. Specifically, it is preferable to use the same deposition method as that for the photoconductive layer in terms of productivity of the electrophotographic photoreceptor.

For example, by glow discharge method, a-SiC:
In order to form the surface layer 105 made of H and X, basically, a source gas for supplying Si that can supply silicon atoms (Si) and a source gas for supplying C that can supply carbon atoms (C). When,
Source gas for supplying H or // capable of supplying hydrogen atom (H)
And a source gas for X supply capable of supplying a halogen atom (X) are introduced in a desired gas state into a reaction vessel capable of reducing the pressure inside to cause glow discharge in the reaction vessel, and a predetermined amount is preliminarily set. A layer made of a-SiC: H, X may be formed on the substrate 101 on which the photoconductive layer 103 is formed at a position.

In order to form the surface layer 105 having the characteristics capable of attaining the object of the present invention, it is necessary to appropriately set the temperature of the substrate 101, the gas pressure in the reaction vessel, and the discharge power as desired.

The temperature (Ts) of the substrate 101 is appropriately selected according to the layer design, but in the usual case, it is preferably 150 to 350 ° C, more preferably 170 to 33 ° C.
It is desirable to set the temperature to 0 ° C, optimally 190 to 310 ° C.

Similarly, the gas pressure in the reaction vessel is appropriately selected depending on the layer design, but in the usual case, it is preferably 1 × 10 ⁻² to 2 × 10 ² Pa, preferably 5 × 10 5.
^{-2 to} 5 × 10 ¹ Pa, optimally 1 × 10 ^-1 to 2 × 10 ¹ Pa
Is preferred.

Similarly, the discharge power is appropriately selected in the optimum range according to the layer design. For example, a-SiC: H, X
In that case, it is desirable to set the ratio P / F of the discharge power (P) to the total flow rate (F) of the silicon-containing gas and the carbon-containing gas in the range of 5 to 50.

In the present invention, the above-mentioned ranges are mentioned as desirable numerical ranges of the substrate temperature, the gas pressure and the discharge power for forming the surface layer, but the conditions are not usually decided independently and separately. It is desirable to determine the optimum value on the basis of mutual and organic relationships so as to form a surface layer having desired characteristics.

In addition, in the light receiving member of the present invention, it is possible to prevent carriers having a polarity opposite to that of the above-mentioned upper blocking layer from being injected from the substrate side between the substrate 101 and the photoconductive layer 103. Therefore, it is more preferable to provide the lower blocking layer. This lower blocking layer may be formed by using a silicon-containing gas and a carbon-containing gas in the same manner as the upper blocking layer, or by appropriately combining a nitrogen-containing gas, an oxygen-containing gas, etc. instead of the carbon-containing gas. To improve the stopping power and the adhesion. Further, a high resistance type blocking layer to which carbon, nitrogen, oxygen, etc. are appropriately combined and added may be used, but by appropriately adding a gas containing Group 15 of the periodic table, holes are injected as an n-type semiconductor. You may block it.

Next, the apparatus and film forming method for producing the electrophotographic photosensitive member will be described in detail.

FIG. 2 shows an example of a deposited film forming apparatus capable of suitably using a high frequency wave in the VHF band, which is a cylindrical substrate 201.
FIG. 3 is a schematic configuration diagram of an apparatus capable of suitably depositing an electrophotographic photosensitive member on top.

In FIG. 2, the cathode electrode 204 is shown in the reaction vessel 2.
02 is an apparatus for producing an amorphous silicon photoconductor, which is installed outside the reactor 02 and has a plurality of cylindrical substrates 201 installed in the reaction container 202. Note that FIG. 3 shows a cross-sectional view taken along the line AA ′ of FIG.

The apparatus shown in FIG. 2 has two high frequency power sources 20.
The high frequency power having two kinds of frequencies oscillated from 7 and 208 is combined in the matching box 209 and applied to the feeding point of the power branch 213, and the plurality of cathode electrodes 204 installed outside the reaction vessel 202 to the reaction vessel Electric power is supplied to the inside of the reaction vessel 202 to generate plasma in the reaction vessel 202 to form a deposited film.

In order to efficiently introduce the high-frequency power emitted from the cathode electrode 204 into the reaction container 202, the side wall of the cylindrical reaction container 202 is made of a dielectric ceramic. Specific examples of ceramic materials include alumina, titanium dioxide, aluminum nitride, boron nitride, zircon, cordierite, zircon-cordierite, silicon oxide, and beryllium oxide mica-based ceramics. Of these, alumina, aluminum nitride, and boron nitride are preferable from the viewpoints of suppressing the mixing of impurities during vacuum processing, heat resistance, and the like.

Furthermore, the reaction apparatus shown in FIG.
Six cylindrical substrates 201 are installed in the No. 02 on the same circumference at equal intervals. Although the number of the cylindrical substrates 201 is six in FIG. 2, it can be arbitrarily changed according to the diameters of the reaction container and the cylindrical substrates. Also,
Six gas introducing pipes 203 for introducing gas are installed at equal intervals on the same circumference outside the arrangement circle of the cylindrical substrate. Also for this gas introduction pipe, any number can be used as long as the gas can be uniformly supplied.

Further, the power branch 213 and each cathode electrode 2
The connection of 04 may be connected via a capacitor.

The outline of deposition film formation using the apparatus of FIG. 2 will be described below.

First, the cylindrical substrate 20 is placed in the reaction vessel 202.
1 is installed, and the inside of the reaction vessel 202 is exhausted through an exhaust pipe by an exhaust device (not shown). Then, the cylindrical substrate 201 is heated to 20 by a heater (not shown) while flowing an inert gas.
It is heated and controlled to a predetermined temperature of about 0 ° C to 300 ° C.

When the temperature of the cylindrical substrate 201 reaches a predetermined temperature, the gas is supplied and adjusting means means (not shown) is used.
A source gas is introduced into the reaction vessel 202. Then, the reaction vessel 2 is controlled by using an exhaust conductance control means (not shown).
The pressure in 02 is between 0.05 and 40 Pa, preferably between 0.1 and 20
Set to a predetermined pressure of Pa. After confirming that the pressure in the reaction vessel 202 has stabilized, the high frequency power is applied to the high frequency power source 2
It supplies to the cathode electrode 204 from 07 and 208 through the matching box 209. As a result, high-frequency power of two different frequencies is introduced into the reaction container 202, glow discharge occurs in the reaction container 202, the source gas is excited and dissociated, and a deposited film is formed on the cylindrical substrate. During formation of the deposited film, the cylindrical substrate 201 is rotated at a predetermined speed by the motor 211 via the rotary shaft 210, so that the deposited film is formed over the entire circumference of the surface of the cylindrical substrate 201.

After the desired film thickness is formed, the high frequency power supply is stopped, and then the source gas supply is stopped to complete the formation of the deposited film. By repeating the same operation a plurality of times, a desired light-receiving layer having a multilayer structure is formed.

The high frequency power sources 207 and 208 have a relationship of oscillation frequencies, for example, the high frequency power source 207 is the first high frequency.
When the first high-frequency power source that supplies (frequency f1, power value P1) and the second high-frequency power source that supplies the second high frequency (frequency f2, power value P2) are 208, 30 MHz ≦ f2 <f1 ≦ 250 MHz A power source that can satisfy 0.1 ≦ P2 / (P1 + P2) ≦ 0.9 is used.

Further, the first high frequency power source may be provided with a high pass filter having a cutoff frequency characteristic lower than f1 and higher than f2. Similarly, the second high frequency power supply may be provided with a low pass filter having a cutoff frequency characteristic higher than f2 and lower than f1. The higher the frequency selectivity is, the more preferable the other power can be because it can reduce the electric power of the other that goes around to each high-frequency power source.

Further, it is more preferable that the frequency range is 50 MHz or more because the deposition rate is further increased.

It is more preferable that the electric power range is 0.2 ≦ P2 / (P1 + P2) ≦ 0.7. Further, the upper limit of the electric power ratio is set to f2 / f1 to stabilize the discharge. Is most preferable.

It is more preferable that the frequency range is set to the range of 0.5 <f2 / f1 ≦ 0.9 because a higher standing wave suppressing effect can be obtained.

In the case of the device as shown in FIG. 2, for example, a method in which f1 and f2 are independently fed to each electrode can be considered.
More preferably, it is desirable to feed power to f1 and f2 from the same direction of the same rod-shaped electrode. Actually, after f1 and f2 are combined (superposed), each cathode electrode is uniformly fed from the same direction through the branch. With such a configuration, the effect of suppressing the standing wave can be obtained more effectively, which is preferable.

The present invention will be specifically described below with reference to experimental examples and examples, but the present invention is not limited to these.

Experimental Example << Experimental Example 1 >> A single layer film corresponding to the upper blocking layer of the electrophotographic photosensitive member was formed under the conditions shown in Table 1 using the vacuum processing apparatus shown in FIG. As the substrate to be processed, 1 × 1.5-inch polished glass (# 7059, manufactured by Corning Incorporated) was used, and several glass plates were arranged in the longitudinal direction and placed on a substrate holder. Here, the substrate holder is a cylinder made of SUS304, and a part of the circumference is cut out to expose two flat surfaces. Glass substrates are installed in rows on these two surfaces, and the substrates are clamped by nails. A jig that holds and supports it. A glass substrate was placed on the flat surface in the two directions. By arranging this cylinder instead of the cylindrical substrate in the figure, it becomes possible to deposit a film under the same conditions as when the electrophotographic photosensitive member was produced.

The deposition film formation using such an apparatus was roughly as follows.

First, the exhaust pipe 20 is exhausted by an exhaust device (not shown).
The reaction vessel 202 was evacuated through 5. Then, 1000 ml / m was introduced into the reaction vessel 202 from a source gas supply means (not shown).
The substrate was heated and controlled to 190 ° C. by a heating element (not shown) while supplying in (normal) He.

Then, the supply of Ar was stopped and the reaction vessel 20
2 was exhausted by an exhaust device (not shown), and then the flow rates of the SiH ₄ gas and the CH ₄ gas were changed variously as in the deposition film forming conditions shown in Table 1 to obtain seven kinds of a-Si 1 from A to Si. -xCx:
A deposited film of H: B was deposited to about 1 μm. At this time, the sum of the flow rates of SiH ₄ gas and CH ₄ gas is 100 ml /
The flow rate of B ₂ H ₆ was adjusted so that the initial dark conductivity was 5 × 10 ⁻¹² S / cm as measured by the method described later. In addition, the following experimental example,
In the examples, B ₂ H ₆ gas diluted with H ₂ gas to about 0.3% is used, and in the table, it is expressed as the substantial concentration of B ₂ H ₆ gas with respect to SiH ₄ gas. At this time,
Two high frequency power supplies with different frequencies are used.
When the total power of the two high-frequency power supplies is 700 W, the power of the power supply with the higher frequency is P1, and the power of the lower power supply is P2, P2 / (P1 + P2) is 0.5 (P1: P2 = 1: 1). ) Was formed as a deposited film. During the film deposition, the substrate holder was rotated and the film was evenly deposited on the glass substrate placed in two directions.

After forming the deposited film, the reaction vessel 202 was purged with Ar and then leaked with N ₂ gas to take out the deposited film. Immediately after taking out, the deposited film was put in a dark box to block light. Then, apply 25 to all the substrates in one row of this deposited film.
A comb-shaped mask having a gap of 0 μm was placed, and 1000 Å of Cr was deposited by an ordinary vacuum deposition method to form a comb-shaped electrode on the surface. The other row did not have electrodes deposited for making optical measurements.

[0149]

[Table 1]

The initial dark conductivity, σ0, was measured for the column with the electrode deposited and the optical energy bandgap was measured for the column with no electrode deposited. For example Si
H ₄ = 60 ml / min (normal), CH ₄ = 40 ml / min (nor
The optical energy bandgap of the film prepared by the above method was about 2.12 eV. Such optical measurements were performed on all films prepared under different conditions.

Next, these films were irradiated with light having a wavelength corresponding to 90% of the optical energy band gap (about 650 nm in the above example). Specifically, using a power unit (a filter type spectral power control unit manufactured by Optel Co., Ltd.) that combines a halogen light monochromator and an ND filter, a power meter (Optical Multimeter Q8221, manufactured by Advantest Co., Ltd.,
With reference to the value of the optical sensor Q82214), in the above example, 650 nm of monochromatic light is emitted at an intensity of 4 mW / cm ² , and 1 is applied to the gap part of the electrode of the film on which the comb-shaped electrode is vapor-deposited.
Irradiate for 20 minutes. The change rate of dark conductivity (σ ₀ −σ ₁ ) / σ ₀ was calculated from the dark conductivity σ ₁ after light irradiation.

Next, an electrophotographic photosensitive member using the film having different initial dark conductivity as an upper blocking layer was prepared. Using the vacuum processing apparatus shown in FIG. 2, a lower blocking layer, a photoconductive layer, an upper blocking layer, and a surface layer were formed in this order on a mirror-finished aluminum cylinder (substrate) having a diameter of 80 mm under the conditions shown in Table 2. Deposition was performed to prepare an electrophotographic photosensitive member. At this time, as the high frequency power source, a high frequency power source having the same two kinds of frequencies as those used for the film deposition on the above-mentioned glass substrate was used, and the ratio of the two powers was fixed at 1: 1 and the total power was calculated as shown in Table 2. As shown in FIG.

[0153]

[Table 2]

The produced light-receiving member was set in an electrophotographic apparatus (iR-5000 manufactured by Canon, which was modified into a negative charging system for experiments), and potential characteristics and image characteristics were evaluated.

At this time, the process speed is 265 mm / sec.
, And use an LED with a wavelength of 650 nm for static elimination.
The amount of light was 4 lx · s. In such a charging process, the surface potential meter (TREK Co. Mo
The surface potential of the light receiving member was measured by the potential sensor of del 344), and this value was defined as the charging ability. The charging ability was measured at 10 points in the axial direction, and the difference between the maximum value and the minimum value was defined as uneven charging ability.

Next, the ghost characteristics were evaluated. First, the main charger is adjusted so that the dark portion potential at the developing device position becomes a predetermined value, and then the image exposure intensity is adjusted so that the light portion potential when a predetermined blank sheet is used as an original becomes a predetermined value. In this state, Canon Ghost Chart (part number: FY9
-9040) with black dots with a reflection density of 1.1 and a diameter of 5 mm affixed at intervals of 10 mm in the direction of the generatrix of the photoconductor is placed on the platen, and a copy of a Canon halftone chart is overlaid on it. In the image, it was performed by measuring the difference between the reflection density of a black circle having a diameter of 5 mm and the reflection density of the halftone, which is observed on the halftone copy.

Table 5 shows the results obtained above.

<< Comparative Experimental Example 1 >> As in Experimental Example 1, FIG.
A single layer film corresponding to the upper blocking layer was formed on the glass under the conditions shown in Table 3 by using the vacuum processing apparatus shown in FIG.

After forming the deposited film, the reaction vessel 307 was purged with Ar and then leaked with N ₂ gas to take out the deposited film. Immediately after taking out, the deposited film was put in a dark box to block light. Then, apply 25 to all the substrates in one row of this deposited film.
A comb-shaped mask having a gap of 0 μm was placed, and 1000 Å of Cr was deposited by an ordinary vacuum deposition method to form a comb-shaped electrode on the surface. The other row did not have electrodes deposited for making optical measurements.

[0160]

[Table 3]

The initial dark conductivity, σ0, was measured for the column with the electrode deposited and the optical energy bandgap was measured for the column with no electrode deposited. The optical energy band gap was about 2.1 eV. Such optical measurements were performed on all films prepared under different conditions.

Next, for this film, a wavelength corresponding to 90% of the optical energy band gap (about 655 nm)
Of monochromatic light of 4 mW / cm ^{2 at} an intensity of 4 mW / cm ² for 120 minutes on the electrode gap portion of the film on which the comb-shaped electrode was vapor-deposited,
Similarly, the change rate (σ ₀ -σ ₁ ) / σ ₀ of dark conductivity was calculated from the dark conductivity σ ₁ after light irradiation.

Next, an electrophotographic photosensitive member using this film as an upper blocking layer was prepared. Using the vacuum processing apparatus shown in FIG. 3, a photoconductive layer, an upper blocking layer and a surface layer were deposited in this order on a mirror-finished aluminum cylinder (base) having a diameter of 80 mm under the conditions shown in Table 4. An electrophotographic photoreceptor was created.

[0164]

[Table 4]

The produced light receiving member was set in an electrophotographic apparatus (iR-5000 manufactured by Canon was modified into a negative charging system for experiments), and the same potential characteristics and image characteristics as in Experimental Example 1 were evaluated. It was

The obtained results (change rate of dark conductivity σ) are shown in Table 5 together with the results of Experimental Example 1.

Table 5 shows relative evaluation as follows with reference to Comparative Experimental Example 1 as a reference in order to directly show how much the charging performance unevenness and ghost characteristics are improved from the prior art. There is. ⊚: 20% or more improvement as compared with the case of Comparative Experimental Example 1 ○: 10% to 20% compared with the case of Comparative Experimental Example 1
Improvement Δ: Equivalent to that produced in Comparative Experimental Example 1 (difference of less than 10%) ×: Inferior to that produced in Comparative Experimental Example 1

[0168]

[Table 5]

In Comparative Experimental Example 1, σ before and after light irradiation
Virtually no change was observed. Further, based on the charging performance unevenness and ghost characteristics of the conventional photoconductor using the upper blocking layer, the rate of change of σ before and after light irradiation (σ ₀ -σ ₁ ) / σ
It was found that the characteristics of the photoreceptor having the upper blocking layer formed under appropriate conditions such that ₀ was in the range of 10 to 90% were improved as compared with the photoreceptor of Comparative Experimental Example 1. Also,
It was also found that the range of 20% or more and 80% or less is particularly preferable.

Experimental Example 2 As in Experimental Example 1, using the vacuum processing apparatus shown in FIG. 2, a single layer film corresponding to the upper blocking layer was formed on the glass under the conditions shown in Table 6. As in the deposition film forming conditions shown in Table 6, the flow rates of SiH ₄ gas and CH ₄ gas were fixed at 70 and 30 ml / min (normal),
The deposited films H to M made of a-Si _1-x C _x : H: B were deposited by about 1 μm while changing the concentration of the B ₂ H ₆ gas variously. The obtained film was subjected to optical measurement and electrical measurement in the same manner as in Experimental Example 1 to measure the optical energy bandgap, the dark conductivity σ ₀ , and its change rate (σ ₀ -σ ₁ ) / σ ₀ .

[0171]

[Table 6]

Next, electrophotographic photoconductors HM were prepared using the films having different initial dark conductivity as the upper blocking layer. Using the vacuum processing device shown in FIG. 2, the diameter is 80 mm.
A lower blocking layer, a photoconductive layer, an upper blocking layer, and a surface layer were sequentially deposited on the mirror-finished aluminum cylinder (base) under the conditions shown in Table 7 to prepare an electrophotographic photosensitive member. At this time, as the high frequency power source, the high frequency power source of the same two kinds of frequencies as those used for the film deposition on the glass substrate described above was used, and the ratio of the two powers was fixed at 1: 1 to obtain the total power. As shown in FIG.

[0173]

[Table 7]

The produced light-receiving member was set in an electrophotographic apparatus (iR-5000 manufactured by Canon, which was modified into a negative charging system for experiments), and potential characteristics were evaluated.

At this time, the process speed is 265 mm / sec.
, And use an LED with a wavelength of 650 nm for static elimination.
The amount of light was 4 lx · s. In such a charging process, a surface electrometer set at the developing device position of the electrophotographic apparatus.
The surface potential of the light-receiving member was measured by a potential sensor (TRdel, Model 344), and the current value of the charger was adjusted so that it was 300V. Next, the image exposure light source is turned on, and the intensity of the exposure light amount is about 2 to 3 times (actually 0.8 to
1.2 μJ / sec) was applied to lower the surface potential, and the surface potential when the value was sufficiently saturated with respect to the light quantity was taken as the residual potential.

The image deletion is evaluated by preparing a test chart in which a line-and-space pattern in which black portions and white portions are alternately arranged for various line widths is prepared and the minimum line width that can be resolved is obtained. Was measured. That is,
When the line width is reduced to a certain value or less when the line width is narrowed, minute blurring due to the image deletion of the contours of the adjacent black portions on the image overlaps each other, making it practically impossible to resolve. The line width at that time was used as an index representing the degree of image deletion.

Table 8 shows the results obtained above. In Table 8, the degree of image deletion is shown by relative evaluation as follows with Comparative Experimental Example 1 as a reference.

⊚: 20% or more improvement as compared with the case prepared in Comparative Experimental Example 1 ◯: 10% to 20% compared with the case prepared in Comparative Experimental Example 1
Improvement Δ: Equivalent to that produced in Comparative Experimental Example 1 (difference of less than 10%) ×: Inferior to that produced in Comparative Experimental Example 1

[0179]

[Table 8]

With respect to the residual potential, the photosensitive member H has a residual potential of 1/6 or more with respect to charging, which is not so preferable for high contrast, but σ ₀ is 1.
It was found that the residual potentials of the photoconductors I to M of 0 ^-15 S / cm or more were low and good.

Regarding the image flow characteristics, σ ₀ is 1
It was found that the characteristics of the photoreceptor having the upper blocking layer formed under appropriate conditions such that the range was 0 ^-10 S / cm or less were improved as compared with the photoreceptor of Comparative Experimental Example 1.

From the two of the residual potential and the image deletion characteristic,
Preferred σ₀The range of 10^{- 15}-10^-TenS / cm
It was found to be in the range.

Experimental Example 3 Similar to Experimental Example 1, the vacuum processing apparatus shown in FIG. 2 was used to form single-layer films N to S corresponding to the upper blocking layer on the glass under the conditions shown in Table 1. . Among the deposition film forming conditions shown in Table 1, the flow rates of SiH ₄ gas and CH ₄ gas were variously changed, and the composition ratio C / (Si + C) of carbon and silicon in the obtained film was measured by secondary ion mass spectrometry. Law (SIMS)
I looked it up. The results obtained are shown in Table 9. Next, at each carbon ratio, the concentration of B ₂ H ₆ is adjusted so that the dark conductivity σ ₀ and the rate of change (σ ₀ -σ ₁ ) / σ ₀ , which are the characteristics required in the present application, fall within the range of the present application. Table 9 also shows the results of forming films by variously changing the above, and similarly examining the concentration of B atom with respect to the sum of Si atom and C atom by SIMS.

As can be seen from Table 9, when C / (Si + C) is extremely small or extremely large, the proper range of the B concentration for obtaining the characteristics required in the present application is small. . For example, if C / (Si + C) is 0.03, B
Even if only a small amount is added, σ ₀ reaches the upper limit of the preferable range, so the range is very narrow. C / (Si +
Similarly, it is difficult to control B when C) is 0.67. On the other hand, in the case of 0.05 or more and 0.6 or less, the proper range of the B concentration can be swung in the range of one digit or more, which shows that the controllability is good.

The membrane prepared here was placed on the upper surface in the same manner as in Experimental Example 1.
A photoreceptor is created as a blocking layer to prevent uneven charging performance and ghost characteristics.
And the image deletion characteristics were evaluated. Both photoconductors are dark conductive
Rate σ ₀, Its rate of change (σ₀-σ₁) / σ₀Within the scope of the present application
In comparison with the photoconductor prepared in Comparative Experimental Example 1,
It was confirmed that it showed sex. Also, especially C / (Si +
C) is 0.05 to 0.6, and the amount of B is 100 atom ppm to 30,000 atom ppm.
In the range of 1, the chargeability is good because the injection amount is small.
Unevenness is very small, there is no image deletion, and cracks are generated.
There is no raw material and it is extremely good in other electrophotographic characteristics.
Was found.

[0186]

[Table 9]

Experimental Example 4 In the same manner as in Experimental Example 1, using the vacuum processing apparatus shown in FIG. 2, a single layer film corresponding to the upper blocking layer was formed on the glass under the conditions shown in Table 10. As in the deposition film forming conditions shown in Table 10, the flow rates of SiH ₄ gas and CH ₄ gas were fixed at 60 and 40 ml / min (normal), respectively, and the concentration of B ₂ H ₆ gas with respect to SiH ₄ was set to 5000 ppm.
A deposited film of a-Si _1-x C _x : H: B was deposited to about 1 μm. The obtained film was subjected to optical measurement and electrical measurement in the same manner as in Experimental Example 1 to measure the optical energy bandgap, the dark conductivity σ ₀ , and its change rate (σ ₀ -σ ₁ ) / σ ₀ . The obtained optical band gap is 2.15 eV, the dark conductivity σ ₀ is 2 × 10 ^-11 S / cm, and the change rate (σ ₀ -σ ₁ ) / σ ₀ is 3.
It was 0%.

[0188]

[Table 10]

Next, as the upper blocking layer, the above-mentioned preparation conditions are used.
a-Si _1-x C _x : H: B
Various kinds of electrophotographic photosensitive members TZ were prepared by changing variously from 0.01 μm to 1 μm. Using the vacuum processing apparatus shown in FIG. 2, a lower blocking layer was formed under the conditions shown in Table 11 on an aluminum cylinder (substrate) having a diameter of 80 mm and mirror-finished.
A photoconductive layer, an upper blocking layer, and a surface layer were sequentially deposited to form an electrophotographic photosensitive member. At this time, as the high frequency power source, the high frequency power source of the same two kinds of frequencies as those used for the film deposition on the glass substrate described above was used, and the ratio of the two powers was fixed at 1: 1 to obtain the total power. As shown in FIG.

[0190]

[Table 11]

The produced light-receiving member was set in an electrophotographic apparatus (iR-5000 manufactured by Canon was modified into a negative charging system for experiments), and the same potential characteristics and image characteristics as in Experimental Example 1 were evaluated. It was

The chargeability and ghost were measured in the same manner as in Experimental Example 1. What is different from Experimental Example 1 this time is that the experimental example 1 focuses on the axial nonuniformity of the charging ability, but this time, the absolute value is focused on. Using the chargeability in the center of the photoconductors prepared in Comparative Experimental Example 1 as a reference, the chargeability in the center of seven photoconductors having different upper blocking layer thicknesses was measured and compared. The ghost was evaluated by the same method as in Experimental Example 1. Similarly, as the evaluation standard, the photoconductor prepared in Comparative Experimental Example 1 was used.

Table 12 shows the results obtained above. Table 1
In order to clearly show how much the charging performance and the ghost characteristics are improved in comparison with the prior art in Comparative Example 2, relative evaluation is shown as follows with Comparative Experimental Example 1 as a reference.

⊚: 20% or more improvement as compared with the case prepared in Comparative Experimental Example 1 ○: 10% to 20% compared with the case prepared in Comparative Experimental Example 1
Improvement Δ: Equivalent to that produced in Comparative Experimental Example 1 (difference of less than 10%) ×: Inferior to that produced in Comparative Experimental Example 1

[0195]

[Table 12]

Regarding the charging ability, even when the thickness of the upper blocking layer is very thin (0.01 μm), it is equivalent to that of the photoreceptor of Comparative Experimental Example 1, and even if the upper blocking layer of the present application is very thin, the blocking ability is high. It has been shown to exhibit
It has been found that it is desirable that the thickness is m or more, and most preferably 0.05 μm or more.

Further, when the thickness of the upper blocking layer becomes too thick, the ghost characteristics may be deteriorated due to the difficulty of passing electric charges. However, in the present invention, even if the thickness reaches 1 μm, it is shown in Comparative Experimental Example 1. It shows that the ghost characteristics are almost the same as those of conventional photoconductors, and that the charge running property is good. More preferably, it is 0.7 μm or less, optimally
It has been found that 0.5 μm or less is desirable.

From the above two charging properties and ghost characteristics,
The preferable range of the film thickness of the upper blocking layer is 0.01 to 1 μm.
m, more preferably 0.03 to 0.7 μm, optimally 0.05 to 0.5
It was found to be in the μm range.

<Experimental Example 5> According to the conditions for producing the upper blocking layer produced in Experimental Example 4, the vacuum processing apparatus shown in FIG. Lower blocking layer under the conditions shown in
A photoconductive layer, an upper blocking layer, and a surface layer were sequentially deposited to form an electrophotographic photosensitive member. Here, what is different from Table 11 is the substrate heating temperature at the time of forming the upper blocking layer. Simultaneously with the start of the formation of the upper blocking layer, the heating temperature of the substrate is gradually increased from 200 ° C., and at the end of the upper blocking layer, it is just 240 ° C.
So that As a result, the content of hydrogen contained in the upper blocking layer gradually decreases toward the surface side. The temperature may be changed to 200 ° C. during the formation of the surface layer, but here it was kept at 240 ° C. Table 1 for other parts
It is basically the same as 1. The thickness of the upper blocking layer was 0.2 μm.

[0200]

[Table 13]

The photoconductors produced by changing the heating temperature of the substrate were the photoconductor W produced in Experimental Example 4 (having an upper blocking layer thickness of 0.2 μm) and the photoconductor produced in Comparative Experimental Example 1. A thermal shock test was conducted together with this. Each electrophotographic photosensitive member is left for 12 hours in a container adjusted to a temperature of -50 ° C and a humidity of 70%, and immediately thereafter, a temperature of 80 ° C and a humidity of 80%.
Leave for 2 hours in a container adjusted to. After the cycle was repeated 10 times, the number of minute cracks appearing in the image was checked when the image was displayed by the halftone image. In the apparatus shown in FIG. 2, six photoconductors can be obtained by depositing the film once. Therefore, for all six photoconductors, the cracks on the image are checked, and the surface is observed with a microscope. I observed.

The results are shown in Table 14. With the photoconductor W in which the temperature was kept constant during the formation of the upper blocking layer, although it did not appear in the image, it was found by microscopic observation that minute cracks had occurred in two out of six. On the other hand, in all the six photoreceptors, the temperature of which was raised during the formation of the upper blocking layer, no cracks were observed. Comparative Experimental Example 1
In the case of the photoconductor of No. 1, it is almost invisible on the image, but cracks were observed in 6 out of 6 of them by microscopic observation.
With respect to the book, film peeling occurred at the edge (non-image area).

[0203]

[Table 14]

From the above results, it was found that the photoreceptor using the upper blocking layer of the present application is less likely to cause minute cracks and the like and is less likely to cause image defects. Furthermore, if the temperature of the substrate is raised during the formation of the upper blocking layer, the amount of hydrogen contained in the upper blocking layer will gradually decrease toward the surface side, and the stress will be relaxed, so that cracking will become more difficult. understood.

[0205]

EXAMPLES The present invention will be described in more detail below with reference to examples.

Example 1 Using the vacuum processing apparatus shown in FIG. 2, a lower blocking layer, a photoconductive layer and an upper blocking layer were formed under the conditions shown in Table 15 on an aluminum cylinder (substrate) having a diameter of 80 mm and having a mirror finish. Layers and surface layers were deposited in this order to prepare an electrophotographic photoreceptor. At this time, a high frequency power source having two kinds of frequencies was used as the high frequency power source, and the ratio of the two powers was fixed at 1: 1 and the total power was changed in each layer as shown in Table 15.

The upper blocking layer used in this example is a single composition film prepared beforehand on glass at 220 ° C. and has a dark conductivity of 3 × 10 ⁻¹² S / cm and a change rate due to light irradiation. It is 25%, which is confirmed in advance to be within the range of the present application.

[0208]

[Table 15]

The produced light-receiving member was set in an electrophotographic apparatus (iR-5000 manufactured by Canon, which was modified into a negative charging system for experiments), and potential characteristics and image characteristics were evaluated.

Using the same measurement method as in the experimental example, the chargeability and its axial unevenness, ghost characteristics, residual potential, image deletion characteristics, and minute cracks were evaluated. As a result, the potential characteristics and the image characteristics were very good.

Next, the image density unevenness was evaluated as an evaluation of the characteristic unevenness which may be a problem in the CVD using the VHF band frequency. For the image density unevenness, first, the main charger current is adjusted so that the dark part potential at the developing device position becomes a constant value, and then a predetermined blank paper with a reflection density of 0.1 or less is used for the original, and the light at the developing device position is adjusted. The image exposure intensity was adjusted so that the partial potential became a predetermined value. Then, a Canon halftone chart (part number: FY9-9042) was placed on the platen and the reflection density in the entire area on the copy image obtained when copying was evaluated.

As a result, the image density unevenness is extremely small and V
It was found that the characteristic deterioration corresponding to the “standing wave node” expected at the HF band frequency did not occur, and the uniformity of the characteristic was achieved at a high level. Therefore, it has been found that characteristic unevenness can be improved at a high level by superimposing two different high frequencies in an appropriate frequency range with an appropriate power balance as in the present application.

Next, using an idle rotation durability tester (a device for removing the developing device and the paper supply system and repeating the copying process only by charging and exposing), which is also a remodeled electrophotographic device,
The idle rotation was performed for a time equivalent to, 000,000 sheets. After that, the above-mentioned potential characteristics were evaluated, but there was no problem of characteristic deterioration that would appear in an image, and there was no problem.

Therefore, when the upper blocking layer is formed within the range of the present application, the initial electrical characteristics and image characteristics are good, the uniformity is high, and there is no deterioration of characteristics that may cause a problem on the image even after long-term use. It was found that a very good photoreceptor was obtained.

Example 2 Using the vacuum processing apparatus shown in FIG. 2, a lower blocking layer, a photoconductive layer and an upper blocking layer were formed under the conditions shown in Table 16 on an aluminum cylinder (substrate) having a diameter of 80 mm and having a mirror finish. Layers and surface layers were deposited in this order to prepare an electrophotographic photoreceptor. At this time, a high frequency power source having two kinds of frequencies was used as the high frequency power source, and the ratio of the two powers was fixed at 1: 1 and the total power was changed in each layer as shown in Table 16.

Further, in the present embodiment, when the upper blocking layer is formed, in order to prevent interference of exposure light due to the formation of the interface with the photoconductive layer or the surface layer, the refractive index is continuously changed at the interface between the two. I chose Specifically, the gas flow rate is gradually changed at the interface over a period of about 1 to 5 minutes,
A gentle change in composition prevents a sharp change in the refractive index. In Table 16, the portion shown in parentheses shows the change in the gas amount.

[0217] upper blocking layer used in this embodiment (fixed portion), in a single composition film produced in advance at 220 ° C. on glass, dark conductivity, the rate of change by light irradiation, each 2 × 10 ^{- It was 12} S / cm, 45%, which was confirmed in advance to be within the range of the present application. In addition, it has been confirmed in advance that the film thickness in the composition change amount region generated by changing the gas flow rate is thin and therefore does not substantially contribute to the electrophotographic characteristics.

[0218]

[Table 16]

The produced light-receiving member was set in an electrophotographic apparatus (iR-5000 manufactured by Canon, which was modified into a negative charging system for experiments), and potential characteristics and image characteristics were evaluated.

Using the same measuring method as in the experimental example, charging ability and its axial unevenness, ghost characteristics, residual potential, image deletion characteristics, and minute cracks were evaluated. As a result, the potential characteristics and the image characteristics were very good.

Next, similarly to Example 1, the evaluation of image characteristic unevenness was performed. As a result, it was found that the image density unevenness was extremely small and the uniformity of the characteristics was achieved at a high level. Therefore, it has been found that characteristic unevenness can be improved at a high level by superimposing two different high frequencies in an appropriate frequency range with an appropriate power balance as in the present application.

Next, the same idling durability test as in Example 1 was conducted for a time corresponding to 1 million sheets. After that, the above-mentioned potential characteristics were evaluated, but there was no problem of characteristic deterioration that would appear in an image, and there was no problem.

Therefore, when the upper blocking layer is formed within the range of the present application, the initial electrical characteristics and image characteristics are good, the uniformity is high, and there is no deterioration of characteristics that may cause problems on the image even after long-term use. It was found that a very good photoreceptor was obtained.

Example 3 Using the vacuum processing apparatus shown in FIG. 2, a lower blocking layer, a photoconductive layer and an upper blocking layer were formed under the conditions shown in Table 17 on an aluminum cylinder (substrate) having a diameter of 80 mm and having a mirror finish. Layers and surface layers were deposited in this order to prepare an electrophotographic photoreceptor. At this time, a high frequency power source having two kinds of frequencies was used as the high frequency power source, and the ratio of the two powers was fixed at 1: 1 and the total power was changed in each layer as shown in Table 17.

Further, in this embodiment, similarly to the second embodiment, the composition change amount region is provided before and after the formation of the upper blocking layer.

In addition, in this embodiment, after the film deposition by the apparatus of FIG. 2 is completed, an overcoat layer made of non-crystalline carbon with a slight amount of silicon added is provided on the outermost surface.

[0227] upper blocking layer used in this embodiment (fixed portion), in a single composition film produced in advance at 220 ° C. on glass, dark conductivity, the rate of change by light irradiation, each 2 × 10 ^{- It was 12} S / cm, 45%, which was confirmed in advance to be within the range of the present application. In addition, it has been confirmed in advance that the film thickness in the composition change amount region generated by changing the gas flow rate is thin and therefore does not substantially contribute to the electrophotographic characteristics.

[0228]

[Table 17]

The produced light-receiving member was set in an electrophotographic apparatus (iR-5000 manufactured by Canon was modified into a negative charging system for experiments), and the potential characteristics and the image characteristics were evaluated.

Using the same measuring method as in the experimental example, charging ability and its axial unevenness, ghost characteristics, residual potential, image deletion characteristics, and minute cracks were evaluated. As a result, the potential characteristics and the image characteristics were very good.

Next, evaluation of image characteristic unevenness was carried out in the same manner as in Example 1. As a result, it was found that the image density unevenness was extremely small and the uniformity of the characteristics was achieved at a high level. Therefore, it has been found that characteristic unevenness can be improved at a high level by superimposing two different high frequencies in an appropriate frequency range with an appropriate power balance as in the present application.

Next, the same idling durability test as in Example 1 was conducted for a time corresponding to 1 million sheets. After that, the above-mentioned potential characteristics were evaluated, but there was no problem of characteristic deterioration that would appear in an image, and there was no problem.

Next, the developing device and the paper feeding system were returned, and a durability test was carried out by actually copying on paper. It was confirmed that the image was durable up to 100,000 sheets, but image deterioration due to abrasion or the like was extremely unlikely to occur. .

Therefore, when the upper blocking layer is formed within the range of the present application, the initial electrical characteristics and image characteristics are good, the uniformity is high, and there is no deterioration of characteristics that may cause a problem on the image even after long-term use. It was found that a very good photoreceptor was obtained.

Example 4 Using the vacuum processing apparatus shown in FIG. 2, a lower blocking layer, a photoconductive layer 1 and an optical layer were formed under the conditions shown in Table 18 on an aluminum cylinder (substrate) having a diameter of 80 mm and subjected to mirror finishing. A film was deposited in this order on the conductive layer 2, the upper blocking layer, and the surface layer to prepare an electrophotographic photoreceptor. At this time, as the high frequency power source, two types of high frequency power source are used.
The two power ratios were fixed at 1: 1 and the total power was varied in each layer as shown in Table 18.

Further, in this embodiment, similarly to the second embodiment, the composition change amount region is provided before and after the formation of the upper blocking layer.

The upper blocking layer (constant portion) used in this example is a single composition film prepared beforehand on glass at 220 ° C., and its dark conductivity and its rate of change by light irradiation are 5 × 10 ⁻ respectively. ^{It was 12} S / cm, 37%, which was confirmed in advance to be within the range of the present application. In addition, it has been confirmed in advance that the film thickness in the composition change amount region generated by changing the gas flow rate is thin and therefore does not substantially contribute to the electrophotographic characteristics.

[0238]

[Table 18]

The produced light-receiving member was set in an electrophotographic apparatus (iR-5000 manufactured by Canon, which was modified into a negative charging system for experiments), and potential characteristics and image characteristics were evaluated.

Using the same measurement method as in the experimental example, the chargeability and its axial unevenness, ghost characteristics, residual potential, image deletion characteristics, and minute cracks were evaluated. As a result, the potential characteristics and the image characteristics were very good.

Next, evaluation of image characteristic unevenness was carried out in the same manner as in Example 1. As a result, it was found that the image density unevenness was extremely small and the uniformity of the characteristics was achieved at a high level. Therefore, it has been found that characteristic unevenness can be improved at a high level by superimposing two different high frequencies in an appropriate frequency range with an appropriate power balance as in the present application.

Next, the same idling durability test as in Example 1 was conducted for a time corresponding to 1 million sheets. After that, the above-mentioned potential characteristics were evaluated, but there was no problem of characteristic deterioration that would appear in an image, and there was no problem.

Therefore, when the upper blocking layer is formed within the range of the present application, the initial electrical characteristics and image characteristics are good, the uniformity is high, and there is no deterioration in characteristics that may cause problems on the image even after long-term use. It was found that a very good photoreceptor was obtained.

Example 5 Using the vacuum processing apparatus shown in FIG. 2, a lower blocking layer, a photoconductive layer, and an upper blocking layer were formed under the conditions shown in Table 19 on a mirror-finished aluminum cylinder (substrate) having a diameter of 30 mm. Layers and surface layers were deposited in this order to prepare an electrophotographic photoreceptor. At this time, a high frequency power source having two kinds of frequencies was used as the high frequency power source, and the ratio of the two powers was fixed at 1: 1 and the total power was changed in each layer as shown in Table 19.

Further, in this embodiment, similarly to the second embodiment, the composition change amount region is provided before and after the formation of the upper blocking layer.

The upper blocking layer (constant portion) used in this example is a single composition film prepared beforehand on glass at 220 ° C., and its dark conductivity and its rate of change by light irradiation are 8 × 10 ⁻ respectively. ^{It was 13} S / cm, 42%, which was confirmed in advance to be within the range of the present application. In addition, it has been confirmed in advance that the film thickness in the composition change amount region generated by changing the gas flow rate is thin and therefore does not substantially contribute to the electrophotographic characteristics.

[0247]

[Table 19]

The produced light-receiving member was set in an electrophotographic apparatus (a Canon GP-405 modified to a negative charging system for experiments), and potential characteristics and image characteristics were evaluated.

Using the same measurement method as in the experimental example, the chargeability and its axial unevenness, ghost characteristics, residual potential, image deletion characteristics, and minute cracks were evaluated. As a result, the potential characteristics and the image characteristics were very good.

Next, evaluation of image characteristic unevenness was carried out in the same manner as in Example 1. As a result, it was found that the image density unevenness was extremely small and the uniformity of the characteristics was achieved at a high level. Therefore, it has been found that characteristic unevenness can be improved at a high level by superimposing two different high frequencies in an appropriate frequency range with an appropriate power balance as in the present application.

Then, as in Example 1, the developing device and the paper feeding system were removed from the modified electrophotographic apparatus, and the idling durability test was conducted for a time equivalent to 1 million sheets. After that, the above-mentioned potential characteristics were evaluated, but there was no problem of characteristic deterioration that would appear in an image, and there was no problem.

Therefore, when the upper blocking layer is formed within the range of the present application, the initial electrical characteristics and image characteristics are good, the uniformity is high, and there is no deterioration in characteristics that may cause problems on the image even after long-term use. It was found that a very good photoreceptor was obtained.

[0253]

As described above, according to the present invention, at least the conductive substrate, the photoconductive layer made of a non-single crystal material having silicon atoms as a matrix, the upper blocking layer, and the surface are protected. An electrophotographic photoreceptor including a surface layer, comprising: a) a non-single-crystal material having a silicon atom and a carbon atom as a matrix and containing a Group 13 element of the periodic table, b) an initial stage before being exposed to light. Dark conductivity σ0 is 1 ×
10 ^-15 S / cm or more and 1 × 10 ^-10 S / cm or less, c) Dark conductivity after irradiation with light having a wavelength converted to 90% of the optical energy band gap at an intensity of 4 mW / cm 2 for 120 minutes. Where σ1 is the change rate of dark conductivity
Three conditions: (σ ₀ -σ ₁ ) / σ ₀ is 10% or more and 90% or less
By using a film that satisfies all of a) to c) as the upper blocking layer, both potential characteristics and image characteristics can be improved, and uneven charging ability can be suppressed, resulting in deterioration of characteristics that cause problems on the image after long-term use. In addition, it is possible to provide an electrophotographic photosensitive member that can achieve extremely good characteristics in high dimensions.

[Brief description of drawings]

FIG. 1 is a schematic layer structure diagram for explaining a layer structure of a preferred embodiment of an electrophotographic photosensitive member of the present invention.

FIG. 2 is a schematic explanatory view of an apparatus for forming an electrophotographic photosensitive member of the present invention, which is an apparatus for manufacturing an electrophotographic photosensitive member by a glow discharge method using a VHF band high frequency power source.

FIG. 3 is a schematic explanatory diagram of a cross section taken along the line AA ′ in FIG.

[Explanation of symbols]

101 base 102 Lower blocking layer 103 Photoconductive layer 104 upper blocking layer 105 surface layer 106 photoconductive layer 107 photoconductive layer 201 cylindrical substrate 202 reaction vessel 203 gas inlet pipe 204 cathode electrode 205 Exhaust pipe 206 Substrate support 207 High frequency power supply 208 high frequency power supply 209 Matching Box 210 rotation axis 211 motor 212 gear 213 High-frequency power branch unit 215 shield

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hitoshi Murayama             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Nobufumi Tsuchida             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Tomohito Ozawa             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2H068 DA05 DA08 DA14 DA15 DA17                       DA18 DA19 DA32 EA25 EA36                       FC03                 4K030 BA30 CA02 CA15 FA03 JA01                       JA18 LA17

Claims (13)

[Claims] 1. An electrophotographic photoreceptor comprising at least a conductive substrate, a photoconductive layer composed of a non-single-crystal material having silicon atoms as a matrix, an upper blocking layer, and a surface layer for protecting the surface. A) a non-single-crystal material having a silicon atom and a carbon atom as a matrix and containing an element of Group 13 of the periodic table, b) a dark conductivity σ ₀ in an initial state before light is 10
^-15 S / cm or more and 10 ^-10 S / cm or less, c) The dark conductivity after irradiating with light having a wavelength converted to 90% of the optical energy band gap at an intensity of 4 mW / cm ² for 120 minutes, σ _{When set to 1} , the rate of change in dark conductivity
Three conditions: (σ ₀ -σ ₁ ) / σ ₀ is 10% or more and 90% or less
An electrophotographic photoreceptor for negative charging, comprising a film that satisfies all of a) to c) as an upper blocking layer. 2. The electrophotographic photosensitive member according to claim 1, wherein the rate of change (σ ₀ −σ ₁ ) / σ ₀ is 20% or more and 80% or less. 3. Silicon atoms in the upper blocking layer
Ratio of carbon atom to sum of (Si) and carbon atom (C) C / (Si
3. The electrophotographic photosensitive member according to claim 1, wherein the range of + C) is 0.05 ≦ C / (Si + C) ≦ 0.6. 4. The content of Group 13 element of the periodic table with respect to the sum of silicon atoms and carbon atoms in the upper blocking layer is 100 atom ppm or more and 30,000 atom ppm or less. The electrophotographic photosensitive member according to 1. 5. The film thickness of the upper blocking layer is 0.01 μm or more and 1 μm or less.
The electrophotographic photosensitive member according to 1. 6. The upper blocking layer contains hydrogen atoms, and the concentration of hydrogen atoms in the film thickness direction gradually decreases toward the surface layer side. Electrophotographic photoreceptor. 7. A light having a silicon atom as a base material on at least the substrate, wherein a conductive substrate is installed in a reaction vessel capable of depressurization, plasma is generated by high-frequency power, and the substrate is plasma-treated. In the step of producing a photoreceptor by depositing a conductive layer, an upper blocking layer containing a group 13 element containing silicon atoms and carbon atoms as a matrix, and a surface layer for protecting the surface, at least 30 MHz or more at the time of forming the upper blocking layer. Using high frequency power of 250MHz or less,
In addition, the dark conductivity σ ₀ of the upper blocking layer in the initial state before being exposed to light is set to 10 ⁻¹⁵ S / cm or more and 10 ⁻¹⁰ S / cm or less, and the optical energy band gap of the upper blocking layer is reduced. Light with a wavelength converted to 90% has an intensity of 4 mW / c
The rate of change (σ ₀ -σ ₁ ) / σ ₀ of the dark conductivity σ ₁ of the upper blocking layer with respect to σ ₀ after irradiation with m ² for 120 minutes is 1
A method for producing an electrophotographic photosensitive member, which comprises setting the content to 0% or more and 90% or less. 8. The electrophotographic photosensitive member according to claim 7, wherein the rate of change (σ ₀ -σ ₁ ) / σ ₀ is 20% or more and 80% or less. 9. The method for producing an electrophotographic photosensitive member according to claim 7, wherein at least two high frequencies having different frequencies are used when forming the upper blocking layer. 10. When the frequencies of the two different high frequencies are f1 and f2, the relationship between f1 and f2 is f1> f
The method for producing an electrophotographic photosensitive member according to claim 9, wherein 2 and 0.5 <f2 / f1 ≦ 0.9. 11. The relation between P1 and P2 is 0.1 ≦ P2 / (P1 + P2) ≦ 0.9, where P1 and P2 are high-frequency powers of the two different frequencies, respectively. The method for producing an electrophotographic photosensitive member according to claim 9, wherein 12. A high frequency wave of the two different frequencies,
The electrodes are applied to the same electrode.
1. The method for producing an electrophotographic photosensitive member according to 1. 13. The method for manufacturing an electrophotographic photosensitive member according to claim 7, wherein the temperature of the conductive substrate is increased when the upper blocking layer is formed.