JPH06186766A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve the electrical characteristics and image characteristics of the electrophotographic sensitive body formed by using non-single crystalline silicon. CONSTITUTION:This electrophotographic sensitive body is constituted of a conductive base 1101, a photoconductive layer 1103 and a barrier layer 1102 which blocks carrier implantation into the photoconductive layer from a base side direction therebetween. The photoconductive layer 1103 and the barrier layer 1102 are constituted of the non-single crystalline silicon contg. hydrogen composed essentially of Si. The conduction type of the photoconductive layer 1103 is specified to a weak p type if the electrophotographic sensitive body is a positive electrostatic charge and to a weak n type if the electrophotographic sensitive body is a negative electrostatic charge. The conduction type of the barrier layer 1102 is specified to a weak p type when the electrophotographic sensitive body is the positive electrostatic charge and to a weak n type and the local level density of the barrier layer 1102 to 1X10<17> to X 5X10cm<19>cm<-3> when the electrophotographic sensitive body is the negative electrostatic charge. As a result, an optical memory is improved in the state of good electrostatic chargeability and further, the variation in halftone images is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms an image by using an electromagnetic wave such as light (light in a broad sense, which is ultraviolet light, visible light, infrared light, X-ray, γ-ray, etc.). The present invention relates to a photoconductor for electrophotography used in.

[0002]

2. Description of the Related Art In the field of image formation, as a photoconductive material for forming a light receiving layer in a photoreceptor for electrophotography, it is highly sensitive and has a high SN ratio [photocurrent (Ip) / dark current (Id)] and is irradiated. It is required to have characteristics such as having an absorption spectrum adapted to the spectral characteristics of electromagnetic waves, having fast photoresponsiveness and having a desired dark resistance value, and being harmless to the human body during use. In particular, in the case of an electrophotographic photoreceptor 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.

[0003] As a material that has recently received attention based on this point, there is non-single crystal silicon (hereinafter referred to as "A-Si"), for example, German Patent Application Publication No. 274696.
No. 7, JP-A-2855718, and the like, application as a light receiving member for electrophotography is described.

FIG. 2 shows a conventional light receiving member 20 for electrophotography.
2 is a cross-sectional view schematically showing a layer structure of 0, 201 is a conductive support, 202 is a light-receiving layer made of A-Si, and the light-receiving layer has a free surface 203. Such an electrophotographic light-receiving member generally comprises heating the conductive support 201 to 50 ° C. to 400 ° C., and subjecting the support to a vacuum deposition method, a sputtering method, an ion plating method,
A photosensitive layer (photoreceptive layer) 202 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, the plasma CVD method, that is, the method of decomposing the source gas by direct current or high frequency or microwave glow discharge to form the A-Si deposited film on the support is put to practical use as a suitable one.

JP-A-54-121743 proposes an electrophotographic image forming member comprising a support and an A-Si photoconductive layer containing a photoconductive layer as constituent elements. In this publication, by forming a depletion layer in the photoconductive layer, the generation efficiency of photocarriers is improved, the recombination probability is reduced, and the photoresponse speed and residual potential are improved. Further, in JP-A-57-4053, a depletion layer is provided between the photoconductive layer and the support by a lower barrier layer which prevents injection of carriers having the same polarity as the minority carriers, and has a good charge retention ability. A high-sensitivity electrophotographic photoreceptor is provided.

[0006]

However, an electrophotographic photoreceptor having a photoconductive layer made of a conventional A-Si material is used in the electrical and optical methods such as dark resistance, photosensitivity and photoresponsiveness. In terms of photoconductive properties, photoconductive properties, and operating environment properties, as well as stability over time and durability, each property has been individually improved, but further improvements have been made in order to improve overall properties. The reality is that there is room to be done. That is, in recent years, the electrophotographic apparatus is required to have higher speed and higher image quality, and as a result, the electrical characteristics and photoconductive characteristics of the electrophotographic photoreceptor must be improved more than ever before.

For example, when the A-Si material is applied to a current electrophotographic photosensitive member, an optical memory, a charging ability, a residual potential, a sensitivity, and a half value, which have not been a problem in the conventional low-speed charging-exposure-developing process. The sharpness of the tone becomes a problem. In the past, when the chargeability was improved, the residual potential and the optical memory tended to be relatively deteriorated, and it was difficult to achieve both at a high level at the same time. Further, there is a problem that the more it is applied to a high-speed process, the more uneven the halftone, that is, the more noticeable the roughness. In addition, full-color electrophotographic devices can be used with
When the material is applied, in order to improve the gradation and the color reproducibility, more strict improvement is required for the above-mentioned optical memory and halftone roughness.

Therefore, while the characteristics of the A-Si material itself are improved, the layer constitution and the chemical composition of each layer are solved so as to solve the above problems when designing the electrophotographic photoreceptor. However, it is necessary to improve the creation method from a comprehensive viewpoint.

The present invention has been made in view of the above points, and solves various problems in the electrophotographic photoreceptor having the conventional photoreceptive layer composed of the material having the silicon atom as the base as described above. The purpose is to do. That is, even if it is applied to an electrophotographic apparatus using a high-speed process, it exhibits excellent electrical characteristics that do not cause problems of charging ability, residual, sensitivity, and optical memory. Furthermore, a clear image without halftone shading appears. In addition, it is an object of the present invention to provide an electrophotographic photosensitive member which can easily obtain a high-quality image with high resolution and to which an ordinary electrophotographic method can be applied very effectively.

[0010]

The present invention is provided with a conductive support, a photoconductive layer, and between these, and prevents injection of carriers into the photoconductive layer from the side of the support. In an electrophotographic photoreceptor having a barrier layer having a function, the photoconductive layer and the barrier layer are composed of a non-single crystalline material containing hydrogen mainly containing silicon, and the photoconductive layer of The conductivity type is a weak p type when the electrophotographic photoreceptor is positively charged, and a weak n type when the electrophotographic photoreceptor is negatively charged, and the conductivity type of the barrier layer is: When the electrophotographic photoreceptor is positively charged, it is weak p-type, when the electrophotographic photoreceptor is negatively charged, it is weak n-type, and the localized level density of the barrier layer is 1
It is characterized in that it is set to x 10 ¹⁷ cm ^-3 to 5 x 10 ¹⁹ cm ^-3 .

In the present invention, the weak p-type or n-type photoconductive layer and the barrier layer have a difference between half the optical bandgap and the activation energy (hereinafter referred to as "ΔE"). Is preferably 0.01 eV or more and 0.3 eV or less.

The dark resistivity of the photoconductive layer is 5 × 10 ⁹ Ω.
It is preferably cm or more.

The thickness of the photoconductive layer is 1 to 70 μm.
m, and the film thickness of the barrier layer is preferably 0.1 to 5 μm.

The control of the localized level density can be performed by containing oxygen and / or nitrogen and / or carbon in the barrier layer.

If necessary, a charge injection blocking layer for preventing injection of carriers is provided on the photoconductive layer.

The embodiments of the present invention will be described below.

FIG. 1 is a schematic view showing the layer structure of a preferred embodiment of the electrophotographic photoreceptor of the present invention. Electrophotographic photoreceptor 1100 shown in FIG.
Is a conductive support 1101 for an electrophotographic photoreceptor.
A barrier layer 1102 made of A-Si and AS
i) and a photoreceptive layer 1105 having a layer structure including a surface layer 1104 as a protective layer or a charge injection blocking layer provided as necessary, and the photoreceptive layer 1105 is a free surface. 1106.

In the photoconductive layer 1103 of the present invention, the majority carrier is made to have the same charge polarity to prolong the life of the photocarrier generated by imagewise exposure and improve the running property. Therefore, the residual potential and the sensitivity are improved, and the remarkable effect is particularly seen in the reduction of the optical memory. However, when the Fermi level of the photoconductive layer 1103 deviates from the center of the optical bandgap, the dark resistance decreases, so the photoconductive layer 1103 used in the present invention may have a slightly lower resistance than the conventional one. However, in order to further obtain the effect of the present invention, the difference between the activation energy and 1/2 of the optical bandgap is set to within 0.01 to 0.3 eV, and the dark resistance is preferably 5 × 10 5. ^It is preferably designed to be ⁹ Ωcm or more, and optimally 10 ¹⁰ Ωcm or more. Within this numerical range, the improvement in charging ability and the improvement in optical memory are simultaneously satisfied.

The film thickness of the photoconductive layer 1103 in the present invention is appropriately determined to a desired value depending on the process speed of the electrophotographic apparatus to be applied and the purpose, but it is usually 1 to 70 μm, and preferably. It is desirable that the thickness is in the range of 2 to 50 μm.

The barrier layer 1102 of the present invention has a conductivity type of the same polarity as the conductivity type of the photoconductive layer 1103, and the conductivity type has a strength of the same level as or lower than that of the photoconductive layer 1103. Alternatively, by having an n-type and having an appropriate localized level density in the barrier layer 1102, carriers are prevented from being injected into the photoconductive layer 1103 from the support. Conventionally, most of the charging electric field is applied to the depletion layer in the photoconductor in which the depletion layer is used to provide the blocking ability.
The electric field in 3 tended to weaken, and the mobility of photocarriers in the photoconductive layer 1103 was not sufficient. This insufficient traveling property of the optical carrier is emphasized particularly when used in a high-speed process, and it remarkably reflects the subtle difference in film quality of each part of the photoconductor, resulting in halftone density unevenness, so-called rasping. Will be lost. In order to prevent this phenomenon, the conductivity type of the barrier layer 1102 of the present invention is the same as that of the photoconductive layer 1103, and its strength is set to the same level as that of the photoconductive layer 1103. Such a depletion layer is not generated, and further, by setting an appropriate localized level density in the barrier layer 1102, the injected carriers from the support are trapped, and space charges are formed to obtain a blocking ability. There is. With this structure, no depletion layer is generated at the interface between the photoconductive layer 1103 and the barrier layer 1102, and all the above-mentioned problems are solved. Further, since the conductivity type is the same as the charging polarity, the traveling property of the photocarrier is sufficient, so that the residual potential and the sensitivity are improved.

In the present invention, if the localized level density of the barrier layer 1102 for obtaining the above-mentioned effect is too high, the traveling property of photocarriers deteriorates, which causes a residual potential. In addition, since hopping conduction occurs and conversely the injection from the support increases, the density is preferably 5 × 10 ¹⁹ cm ⁻³ or less. Also, if the localized level density is too small, the stopping power decreases,
It is preferably 1 × 10 ¹⁷ cm ⁻³ or more. In order to set a desired localized level density, film formation conditions such as support temperature, electric power,
A film having a desired value can be formed by controlling the degree of vacuum. Further, it can be controlled to some extent by the doping amount of the impurity that controls the conductivity type. However,
In this case, it is desirable in the present invention that the difference ΔE between ½ of the band gap and the activation energy is within 0.01 to 0.3 eV. Furthermore, the inclusion of any of impurity elements such as oxygen, nitrogen, carbon, etc., or a combination thereof, can control the localized level density. Moreover, the control can be performed by changing the kind and flow rate of the raw material gas.

In the case of A-Si, the localized level density is generally "photothermal deflection".
spectroscopy "(PDS)," const
ant photocurrent method "(C
It can be measured using PM) or the like. The present inventors mainly obtained the localized level density by using CPM, but partially PDS was used for samples with high localized level density.

The lower limit of the film thickness of the barrier layer is limited by the film thickness that can sufficiently prevent the injection of carriers from the support 1101. This film thickness of course correlates with the localized level density in the barrier layer 1102, but as a specific numerical value for expressing the effect of the present invention, in the usual case, it is 0.1 μm or more, preferably 0.1.
It is desirable that the thickness is 5 μm or more. On the other hand, the upper limit of the film thickness is determined by the balance between the chargeability and the residual potential desired for the electrophotographic photoreceptor, but in the usual case,
m, preferably 3 μm.

In the present invention, hydrogen is contained in the photoconductive layer 1103 and the barrier layer 1102 by, for example, forming silane (Sil) such as SiH ₄ and Si ₂ H ₆ at the time of forming these layers.
It can be introduced in the form of a silicon compound such as ane), decomposed by the glow discharge plasma CVD method, and automatically contain hydrogen as the film grows. A film containing hydrogen can also be formed by forming a film in a hydrogen atmosphere by a reactive sputtering method.

According to the knowledge of the present inventors, the hydrogen content of the photoconductive layer 1103 and the barrier layer 1102 of the present invention determines whether or not the formed photoconductor 1100 can be applied practically. It has been proved to be one of the major factors that influence and is extremely important. Photoconductive layer 110 of the present invention
3, and in order for the barrier layer 1102 to be adequately applied in practice, the amount of hydrogen contained in each layer is usually 1 to 4
It is desirable that it is 0 atomic%, preferably 5 to 30 atomic%. In order to control the amount of hydrogen contained in each layer, for example, the support temperature at the time of film formation and / or the amount of the starting material used for containing hydrogen introduced into the deposition apparatus system and the discharge power can be controlled. Good.

The photoconductive layer 1103 and the barrier layer 1102 are p-typed.
In order to obtain the n-type or the n-type, an atom whose conductivity is controlled, for example, a group III atom or a group V atom, may be introduced into the deposition apparatus together with another gas during layer formation. Examples of the atoms that control the conductivity include so-called impurities in the field of semiconductors, and atoms belonging to Group III of the periodic table that give p-type conductivity (hereinafter referred to as “III
Group atom) or an atom belonging to group V of the periodic table (hereinafter referred to as “group V atom”) that imparts n-type conductivity.

Specific examples of the group III atom include B
(Boron), Al (aluminum), Ga (gallium),
There are In (indium), Tl (thallium) and the like, and B, Al and Ga are particularly preferable. Specific examples of the Group V atom include P (phosphorus), As (arsenic), Sb (antimony), Bi (bismuth), and the like, with P and As being particularly preferable.

The content of the atoms for controlling the conductivity contained in the photoconductive layer 1103 and the barrier layer 1102 may be contained so as to be controlled to the above Fermi level so as to achieve the object of the present invention. However, as a specific numerical value, usually, 1 × 10 ^{−3 to} 5 × 10 ⁴ atom ppm, preferably 1 × 10 ⁻² to 1 × 10 ⁴ atom ppm, and more preferably 1 ×
It is desirable that the concentration be 10 ^{−1 to} 5 × 10 ³ atomic ppm.

In the present invention, the photoconductive layer 1103 and the barrier layer 1102 are 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, for example, a glow discharge method (low frequency CVD method, high frequency CVD method or microwave C
AC discharge CVD method such as VD method, or DC discharge CVD method
Method, etc.), sputtering method, vacuum deposition method, ion plating method, photo CVD method, thermal CVD method, and various thin film deposition methods. These thin film deposition methods are appropriately selected and adopted depending on factors such as manufacturing conditions, load level under capital investment, manufacturing scale, desired characteristics of electrophotographic photoreceptor to be produced, and the like. Since it is relatively easy to control the conditions for producing an electrophotographic photoreceptor having a glow discharge method,
A sputtering method and an ion plating method are suitable. These methods may be used together in the same system.

Conductive support 1 used in the present invention
101 is, for example, Al, Cr, Mo, Au, I
Examples include metals such as n, Nb, Te, V, Ti, Pt, Pd, and Fe, and alloys thereof, such as stainless steel. Further, at least the surface of the electrically insulating support such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polystyrene, polyamide, or the like, on which the light receiving layer is formed, of the electrically insulating support such as glass or ceramic. It is also possible to use a support obtained by conducting a conductive treatment. Further, it is more preferable that the surface on the side opposite to the side on which the light receiving layer is formed is also subjected to a conductive treatment.

The shape of the support 1101 may be a cylindrical or plate-shaped endless belt having a smooth surface or an uneven surface, and its thickness is appropriately determined so that a desired electrophotographic photoreceptor can be formed. However, the electrophotographic photoconductor 110
When flexibility as 0 is required, it can be made as thin as possible within the range in which the function as a support can be sufficiently exhibited. However, in terms of mechanical strength and the like in terms of manufacturing and handling of the support 1101, it is usually 10 μm.
That is all.

In particular, when image recording is performed by using coherent light such as laser light, unevenness is provided on the surface of the support 1101 in order to eliminate an image defect due to a so-called interference fringe pattern that appears in a visible image. Good. The unevenness provided on the surface is disclosed in JP-A-60-168156 and JP-A-60-168156.
It is prepared by a known method described in JP-A-178457 and JP-A-60-225854. Further, as another method for eliminating the image defect, the surface of the support 1101 may be provided with a concavo-convex shape formed by a plurality of spherical trace dents. That is, the surface of the support 1101 is the electrophotographic photoreceptor 1100.
Has unevenness smaller than the resolving power required for, and the unevenness is due to a plurality of spherical trace depressions. The unevenness due to the plurality of spherical trace depressions provided on the surface of the support is prepared by a known method described in JP-A-61-235661.

The surface layer 1104, which is provided as necessary, improves the surface hardness and serves as a protective layer for improving the abrasion resistance and prevents the charged electric charges from being injected into the photoconductive layer, thereby improving the charging ability. It has a role as a charge injection blocking layer. Typical materials effectively used as the material for forming the surface layer 1104 are Si, SiC, SiN, and S.
Non-single crystal materials such as iO, Al ₂ O ₃ , SiO, SiO ₂
Insulating compounds such as etc., organic insulating compounds such as polyethylene, polycarbonate, polyurethane, parylene, etc.
Etc. The thickness of the surface layer 1104 is usually about 0.1 μm to 2 μm.

In the present invention, the barrier layer, the photoconductive layer, and the surface layer may contain at least one element selected from Group Ia, Group IIa, Group VIa, and Group VIII in the periodic table to a degree of contamination. good. The element may be uniformly distributed in the photoconductive layer, or may be contained uniformly in the photoconductive layer, but in a state of being unevenly distributed in the layer thickness direction. There may be a part containing. Specific examples of the group Ia atom include Li (lithium), Na (sodium), and K (potassium).
Examples of the IIa group atom include Be (beryllium), Mg (magnesium), Ca (calcium), Sr (strontium), and Ba (barium). Further, as the group VIa atom, specifically, Cr (chromium), Mo (molybdenum), W (tungsten) and the like can be cited, and as the group VIII atom, Fe (iron),
Examples thereof include Co (cobalt) and Ni (nickel).

The apparatus and method for forming the deposited film by the DC discharge plasma CVD method will be described in detail below.

FIG. 3 shows DC discharge plasma CVD (hereinafter referred to as "D
FIG. 5 is an explanatory view of a schematic configuration showing an example of an apparatus for manufacturing an electrophotographic photosensitive member by a method referred to as “C-PCVD”).

The structure of the apparatus for producing a deposited film by the DC-PCVD method shown in FIG. 3 is as follows. This apparatus is roughly divided into a deposition apparatus (3100), a source gas supply apparatus (3200), and an exhaust apparatus (not shown) for reducing the pressure inside the reaction vessel (3111). In the reaction vessel (3111) in the deposition apparatus (3100), a cylindrical support (3112) and a heater (311) for heating the support.
3), the raw material gas introduction pipe (3114) is installed.

The source gas supply device (3200) is made of SiH.
_{4, H 2, CH 4,} NO, NH 3, B 2 cylinder source gas such as H ₆ and (from 3221 to 3226) Valve (3231
~ 3236, 3241 to 1246, 3251 to 325
6) and mass flow controller (3211-32)
16), and each source gas cylinder has a valve (3
It is connected to a gas introduction pipe (3114) in the reaction vessel (3111) via 260).

The deposited film can be formed using this apparatus, for example, as follows.

First, a cylindrical support (3112) is installed in the reaction vessel (3111), and the reaction vessel (3111) is evacuated by an exhaust device (not shown) (for example, a vacuum pump). Then, the temperature of the cylindrical support (3112) is controlled to a predetermined temperature of 20 ° C to 500 ° C by the support heating heater (3113).

A raw material gas for forming a deposited film is supplied to a reaction vessel (31
11), the gas cylinder valve (323)
1-3236), leak valve (3117) of the reaction vessel
Check that the inlet valve (3
241 to 246), outflow valves (3251 to 325)
6) After confirming that the auxiliary valve (3260) is opened, first, the main valve (3118) is opened to exhaust the reaction vessel (3111) and the gas pipe (3116).

Next, the reading of the vacuum gauge (3119) is about 5 × 1.
Auxiliary valve (3260) at 0 ^-6 Torr,
Close the outflow valves (3251-256).

After that, gas cylinders (3221-322)
From 6), each gas is introduced by opening the valves (3231 to 236), and the pressure of each gas is adjusted to ² kg / cm ² by the pressure adjuster (3261 to 266). Next, the inflow valves (3241 to 246) are gradually opened to introduce each gas into the mass flow controllers (3211 to 216).

After the preparation for film formation is completed as described above, the barrier layer and the photoconductive layer are formed on the cylindrical support (3112).

When the cylindrical support (3112) reaches a predetermined temperature, the necessary ones of the outflow valves (3251 to 256) and the auxiliary valve (3260) are gradually opened, and the gas cylinders (321 to 326) are set to predetermined positions. Of the gas of the reaction vessel (311) through the gas introduction pipe (3114).
1) Introduce. Next, mass flow controller (3
211 to 216) so that each raw material gas is adjusted to have a predetermined flow rate. At that time, the opening of the main valve (3118) is adjusted while observing the vacuum gauge (3119) so that the pressure in the reaction vessel (3111) becomes a predetermined pressure of 1 Torr or less. When the internal pressure is stable, the DC power source (3115) is set to a desired voltage and the reaction vessel (31
A DC voltage is applied to the inside of 11) to generate a DC glow discharge. The source energy introduced into the reaction vessel is decomposed by this discharge energy, and a predetermined deposited film containing silicon as a main component is formed on the cylindrical support (3112). After the desired film thickness is formed, the supply of the DC power supply (3115) is stopped, the outflow valve is closed to stop the gas from flowing into the reaction container, and the formation of the deposited film is completed.

By repeating the same operation a plurality of times, a desired light-receiving layer having a multilayer structure is formed.

Needless to say, all the outflow valves other than the necessary gas are closed when forming each layer, and each gas is supplied to the reaction vessel (311).
1) In order to avoid remaining in the pipe from the outflow valves (3251 to 2566) to the reaction vessel (3111), the outflow valves (3251 to 256) are closed, the auxiliary valve (3260) is opened, and the main valve is further opened. Valve (31
If necessary, the operation of 18) is fully opened and the system is once evacuated to a high vacuum.

In order to make the film formation uniform, the cylindrical support (3112) is rotated at a predetermined speed by a driving device (not shown) during the film formation.

Needless to say, the above-mentioned gas species and valve operation may be changed according to the conditions for forming each layer.

[0050]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. (Example 1) Using the apparatus for manufacturing an electrophotographic photoreceptor shown in FIG. 3, on a mirror-finished aluminum cylinder, according to the procedure detailed above, by the DC glow discharge method under the manufacturing conditions shown in Table 1. An electrophotographic photosensitive member for positive charging was produced. In the present example, the amount of B ₂ H ₆ and H ₂ in the photoconductive layer was changed to obtain ΔE values of 0.05 eV (p type) and 0.1 eV.
(P type) and 0.25 eV (p type). The value of ΔE is
A sample was prepared in advance on a glass substrate, and an electrophotographic photoreceptor was prepared under the same conditions. It was confirmed that the dark resistance of all the films was 5 × 10 ⁹ Ωcm or more.

The barrier layer of this embodiment has ΔE of 0.1 eV.
(P-type) having a localized level density of 5 × 10 ¹⁷ cm ⁻³ was used.

The electrophotographic photoconductor thus prepared was installed in an electrophotographic apparatus modified from a Canon NP-9800 copying machine for experiments, and the charging ability at the time of positive charging, the residual potential, the optical memory (ghost), and the rubbish were evaluated. I went. Each item is
The following method evaluated. Electrical characteristics Charging ability: ・ The electrophotographic photoconductor is installed in the experimental device, a high voltage of + 6kV is applied to the charger to perform corona charging, and the surface of the dark part of the photoreceptive member for electrophotography is measured by a surface electrometer. Measure the potential.

Residual potential: The electrophotographic photosensitive member is charged to a constant dark surface potential. Immediately, a relatively strong light of a constant light quantity is applied. The light image was emitted by using a halogen lamp light source and excluding light in a wavelength range of 550 nm or less using a filter. At this time, the surface potential of the bright portion of the electrophotographic photoconductor is measured by a surface potential meter.

In each case, ⊚ is “excellently good”, ◯ is “excellent”, Δ is “no practical problem”, and “poor is practical problem”. Image evaluation Optical memory (coast) ... Canon ghost test chart (part number: FY9-9040) with reflection density 1, 1,
Place a black circle of ¢ 5 mm on the front edge of the image on the platen, and place a Canon halftone chart on top of it. The difference between the reflection density and the reflection density of the halftone portion was measured.

Gasatsuki ... A canonical halftone chart (part number: FY9-9042) manufactured by Canon is placed on the platen and copied, and a circular area having a diameter of 0.05 mm is defined as one unit of 100. The image density of the spot was measured, and the variation in the image density was evaluated.

In each case, ⊚ means “excellently good”, ◯ means “good”, Δ means “no problem in practical use”, and × means “problem in practical use”.

[0057]

[Table 1] (Comparative Example 1) In the same manner as in Example 1, a positive charging electrophotographic photoreceptor was prepared under the preparation conditions shown in Table 2. In this comparative example, the amount of B ₂ H ₆ in the photoconductive layer was changed so that the value of ΔE was 0 eV.
5 × for both dark resistance of (i type) and 0.1 eV (n type)
Drum of 10 ⁹ Ωcm or more, and ΔE of 0.2 eV (p
And a dark resistance of less than 5 × 10 ⁹ Ωcm.

The produced electrophotographic photosensitive member was evaluated in the same manner as in Example 1.

The results of Example 1 and Comparative Example 1 are shown in Table 2. The conductivity type of the photoconductive layer is the same polarity as the charging potential (p type), ΔE is within 0.01 to 0.3 eV, and the dark resistance is 5
It can be seen that the optical memory is improved at × 10 ⁹ or more.

[0060]

[Table 2] (Example 2) In the same manner as in Example 1, using the electrophotographic photosensitive member manufacturing apparatus shown in FIG. 3, negative charging electrophotographic photosensitive members were manufactured under the manufacturing conditions shown in Table 3. In this example, the amount of B ₂ H ₆ or PH ₃ and H ₂ in the photoconductive layer was changed to obtain ΔE values of 0.05 eV (n type), 0.1 eV (n type), and 0.
It was set to 25 eV (n). Regarding the value of ΔE, a sample was prepared in advance on a glass substrate, and an electrophotographic photoreceptor was prepared under the same conditions. Both films have a dark resistance of 5 × 10 ⁹ Ωcm
It was confirmed that there was above.

The barrier layer of this example has a ΔE of 0.3 eV.
(N-type) having a localized level density of 5 × 10 ¹⁷ cm ⁻³ was used.

The produced electrophotographic photosensitive member was set in an electrophotographic apparatus which was modified from a Canon copying machine NP-9800 for an experiment, and the charging ability at the time of negative charging, residual potential, rubbing, and ghost were the same as in Example 1. Was evaluated.

[0063]

[Table 3] (Comparative Example 2) In the same manner as in Example 1, a negative charging electrophotographic photoconductor was produced under the production conditions shown in Table 2. In this comparative example, by changing the amount of B ₂ H ₆ or PH ₃ and H ₂ in the photoconductive layer,
A drum having a dark resistance of 5 eV (i type), 0.1 eV (p type) of 5 × 10 ⁹ Ωcm or more, and a ΔE of 0.2.
A photoreceptor having an eV (n type) and a dark resistance of less than 5 × 10 ⁹ Ωcm was prepared.

The produced electrophotographic photosensitive member was evaluated in the same manner as in Example 2.

The results of Example 2 and Comparative Example 2 are shown in Table 4. The conductivity type of the photoconductive layer has the same polarity as the charging potential and Δ
E is within 0.01 to 0.3 eV and the dark resistance is 5 × 10 ⁹
From the above, it can be seen that the optical memory is improved.

[0066]

[Table 4] (Embodiment 3) Using the electrophotographic photosensitive member manufacturing apparatus shown in FIG. 3, on a mirror-finished aluminum cylinder, according to the procedure detailed above, by the DC glow discharge method under the manufacturing conditions shown in Table 5. An electrophotographic photosensitive member for positive charging was produced. In this embodiment, the barrier layer is formed by ΔE: 0.01 eV (p type), Δ
E: 0.08 eV (p type), ΔE: 0.2 eV (p
Type) and ΔE: 0.3 eV (p type).
In each case, the localized level density was 5 × 10 ¹⁷ cm ⁻³ . still,
The ΔE and the localized level density were controlled by the B ₂ H ₆ gas flow rate and the film formation rate during film formation. Each parameter was prepared by measuring a sample on a glass substrate in advance, and an electrophotographic photoreceptor was prepared under the same conditions.

The photoconductive layer of this example had a ΔE of 0.11.
An eV (p type) having a dark resistance of 1 × 10 ¹² Ωcm was used.

The produced electrophotographic photosensitive member was set in an electrophotographic apparatus modified from Canon Copier NP-9800 for experiment, and the charging ability at the time of positive charging, the residual potential, the roughness, and the ghost were evaluated.

[0069]

[Table 5] (Comparative Example 3) In the same manner as in Example 3, a positive charging electrophotographic photosensitive member was produced. In this comparative example, the barrier layer is ΔE: 0 eV.
(I type), ΔE: 0.32 eV (p type), ΔE: 0.1
A type of 5 eV (n type) was created. The localized level density was set to 5 × 10 ¹⁷ cm ⁻³ as in Example 3.

The produced electrophotographic photosensitive member was evaluated in the same manner as in Example 3.

The results of Example 3 and Comparative Example 3 are shown in Table 6. The photoreceptor of the present invention has improved halftone shading.

[0072]

[Table 6] (Example 4) In the same manner as in Example 3, a negative charging electrophotographic photoconductor was produced under the production conditions shown in Table 7 using the electrophotographic photoconductor production apparatus shown in FIG. In this embodiment, the barrier layers are ΔE: 0.01 eV (n type), ΔE: 0.08 eV (n
Type), ΔE: 0.2 eV (n type), ΔE: 0.3 eV
Four types (n type) were created. In each case, the localized level density was 5 × 10 ¹⁷ cm ⁻³ . The ΔE and the localized level density were controlled by the B ₂ H ₆ gas or B ₂ H ₆ gas flow rate and the film formation rate during film formation. Each parameter was prepared by measuring a sample on a glass substrate in advance, and an electrophotographic photoreceptor was prepared under the same conditions.

The photoconductive layer of this example had a ΔE of 0.11.
An eV (n type) having a dark resistance of 1 × 10 ¹² Ωcm was used.

The electrophotographic photoconductor thus prepared was installed in an electrophotographic apparatus modified from Canon Copier NP-9800 for experiments, and the charging ability at the time of negative charging, the residual potential, the roughness, and the ghost were evaluated.

[0075]

[Table 7] (Comparative Example 4) A negative charging electrophotographic photoreceptor was prepared under the same conditions as in Example 4. In this comparative example, the barrier layer is ΔE:
0 eV (i type), ΔE: 0.32 eV (n type), ΔE:
Three types of 0.15 eV (p type) were created. The localized level density was set to 5 × 10 ¹⁷ cm ⁻³ as in Example 4.

The produced electrophotographic photosensitive member was evaluated in the same manner as in Example 4.

The results of Example 4 and Comparative Example 4 are shown in Table 8. The photoreceptor of the present invention has improved halftone shading.

[0078]

[Table 8] (Example 5) Using the electrophotographic photoconductor manufacturing apparatus shown in FIG. 3, on a mirror-finished aluminum cylinder, according to the procedure detailed above, by the DC glow discharge method under the manufacturing conditions shown in Table 9. An electrophotographic photosensitive member for positive charging was produced. In this example, the barrier layer was ΔE: 0.08 eV (p-type), and the localized level density was 1 × 10 ¹⁷ cm ⁻³ , 1 × 10 ¹⁸ cm.
^-3 , 5 × 10 ¹⁹ cm ^-3 were prepared. The ΔE and the localized level density were controlled by the B ₂ H ₆ gas flow rate and the H ₂ gas flow rate during film formation. Each parameter was prepared by measuring a sample on a glass substrate in advance, and an electrophotographic photoreceptor was prepared under the same conditions.

The ΔE of the photoconductive layer of this example was 0.11.
An eV (p type) having a dark resistance of 1 × 10 ¹² Ωcm was used.

The electrophotographic photoconductor thus prepared was installed in an electrophotographic apparatus modified from Canon Copier NP-9800 for experiment, and the charging ability at the time of positive charging, the residual potential, the roughness, and the ghost were evaluated.

[0081]

[Table 9] (Comparative Example 5) In the same manner as in Example 3, a positive charging electrophotographic photosensitive member was produced. In this comparative example, the barrier layer is ΔE: 0.0
8 eV (p-type) and a localized level density of 1 × 10 ¹⁶ c
Three types of m ⁻³ , 5 × 10 ¹⁶ cm ⁻³ , and 8 × 10 ¹⁹ cm ⁻³ were prepared.

The produced electrophotographic photosensitive member was evaluated in the same manner as in Example 5.

The results of Example 5 and Comparative Example 5 are shown in Table 10. The photoreceptor of the present invention has improved halftone shading.

[0084]

[Table 10] (Example 6) In the same manner as in Example 3, using the electrophotographic photosensitive member manufacturing apparatus shown in FIG. 3, negative charging electrophotographic photosensitive members were manufactured under the manufacturing conditions shown in Table 11. In this embodiment, the barrier layer is ΔE: 0.08 eV (n type), and the localized level density is 1
× 10 ¹⁷ cm ^-3 , 1x10 ¹⁸ cm ^-3 , ^{5x10 19} cm ^-3
3 types were created. The ΔE and the localized level density were controlled by the flow rates of B ₂ H ₆ gas and H ₂ gas during film formation. Each parameter was prepared by measuring a sample on a glass substrate in advance, and an electrophotographic photoreceptor was prepared under the same conditions.

The photoconductive layer of this example had a ΔE of 0.11.
An eV (n type) having a dark resistance of 1 × 10 ¹² Ωcm was used.

The electrophotographic photoconductor thus prepared was installed in an electrophotographic apparatus modified from Canon Copier NP-9800 for experiments, and the charging ability at the time of negative charging, the residual potential, the roughness, and the ghost were evaluated.

[0087]

[Table 11] (Comparative Example 6) In the same manner as in Example 4, a negative charging electrophotographic photosensitive member was produced. In this comparative example, the barrier layer is ΔE: 0.0
8 eV (p-type) and a localized level density of 1 × 10 ¹⁶ c
Three types of m ⁻³ , 5 × 10 ¹⁶ cm ⁻³ , and 8 × 10 ¹⁹ cm ⁻³ were prepared.

The produced electrophotographic photosensitive member was evaluated in the same manner as in Example 4.

The results of Example 6 and Comparative Example 6 are shown in Table 12. The photoreceptor of the present invention has improved halftone shading.

[0090]

[Table 12] (Example 7) The same experiment as in Example 5 was performed. However, in the present example, when the localized level density was controlled by adjusting the NO gas flow rate instead of the film formation rate, a clear image was obtained exactly as in Example 5. Example 8 An experiment exactly the same as in Example 6 was performed. However, in this example, when the localized level density was controlled by adjusting the NO gas flow rate instead of the film formation rate, a clear image was obtained exactly as in Example 6. (Example 9) An experiment similar to that of Example 5 was performed. However, in this example, when the localized level density was controlled by adjusting the CH ₄ gas flow rate instead of the film formation rate, a clear image was obtained exactly as in Example 5. (Example 10) An experiment similar to that of Example 6 was performed. However, in this example, when the localized level density was controlled by adjusting the CH ₄ gas flow rate instead of the film forming rate, a clear image was obtained exactly as in Example 6.

[0091]

As described above, according to the electrophotographic photoreceptor of the present invention, the conventional electrophotographic photoreceptor composed of A-Si is required to have high speed and high image quality in recent years. It can solve various problems when it is applied to an electrophotographic apparatus, and exhibits particularly excellent electrical characteristics, optical characteristics, photoconductive characteristics, and image characteristics.

Particularly in the present invention, by setting the conduction type of the photoconductive layer to a weak conduction type having the same polarity as the charging polarity, the residual potential and the optical memory can be improved without deteriorating the charging ability. Furthermore, by setting the conductivity type of the barrier layer to the same polarity and strength as the photoconductive layer, a depletion layer is prevented from occurring between the photoconductive layer and the barrier layer, and the localized level in the barrier layer is further improved. By controlling the density appropriately, injection of carriers from the support is effectively blocked. With the above configuration, it is possible to prevent the image from being unsteady in the halftone generated in the high-speed process.

[Brief description of drawings]

FIG. 1 is a schematic layer configuration diagram for explaining a layer configuration of a preferred embodiment of an electrophotographic light-receiving member of the present invention.

FIG. 2 is a schematic layer configuration diagram showing an example of the layer configuration of a conventional electrophotographic light-receiving member.

FIG. 3 is an example of an apparatus for forming a light-receiving layer of a light-receiving member for electrophotography of the present invention, which is a schematic view of an apparatus for manufacturing a light-receiving member for electrophotography by a glow discharge method using direct current (DC). FIG.

[Explanation of symbols]

 1100,200 Electrophotographic Photoreceptor 1101,201 Conductive Support 1102 Barrier Layer 1103 Photoconductive Layer 1104 Surface Layer 1105,202 Photoreceptive Layer 1106,203 Free Surface 3100 Deposition Device 3111 Reaction Vessel 3112 Cylindrical Support 3113 Support Heater for heating 3114 Raw material gas introduction pipe 3115 Direct current power supply 3116 Raw material gas piping 3117 Reaction vessel leak valve 3118 Main exhaust valve 3119 Vacuum gauge 3200 Raw material gas supply device 3211-3216 Mass flow controller 3221-326 Raw material gas cylinder 3231-236 Raw material gas cylinder valve 3241- 3246 Gas inflow valve 3251 to 3256 Gas outflow valve 3261 to 3266 Pressure regulator

Claims (6)

[Claims] 1. A conductive support, a photoconductive layer, and a barrier layer provided between them and having a function of preventing injection of carriers into the photoconductive layer from the side of the support. In the electrophotographic photoreceptor having, the photoconductive layer and the barrier layer are composed of a non-single crystalline material containing hydrogen mainly composed of silicon, and the conduction type of the photoconductive layer is the electrophotographic layer. When the photoconductor is positively charged, it is weak p-type, when the electrophotographic photoconductor is negatively charged, it is weak n-type, and the conductivity type of the barrier layer is positive. It is a weak p-type when it is charged, a weak n-type when the electrophotographic photoreceptor is negatively charged, and the localized level density of the barrier layer is from 1 × 10 ¹⁷ cm ⁻³ 5 × 10 ¹⁹ cm
An electrophotographic photosensitive member characterized by being ^-3 . 2. The weak p-type or weak n-type photoconductive layer and the barrier layer have a difference ΔE between half the optical bandgap and activation energy of 0.01 eV or more and 0.3 eV.
The electrophotographic photoreceptor according to claim 1, which is V or less. 3. The dark resistivity of the photoconductive layer is 5 × 10 ⁹ Ω.
It is more than cm, Claim 1 or Claim 2 characterized by the above-mentioned.
The electrophotographic photoconductor described. 4. The barrier layer is oxygen and / or nitrogen and / or
Alternatively, the electrophotographic photosensitive member according to any one of claims 1 to 3, which contains carbon. 5. The electrophotographic photosensitive material according to claim 1, wherein a charge injection blocking layer for preventing carrier injection is provided on the photoconductive layer. body. 6. The film according to claim 1, wherein the photoconductive layer has a thickness of 1 to 70 μm, and the barrier layer has a thickness of 0.1 to 5 μm. The electrophotographic photoconductor described.