JP3279926B2 - Electrophotographic photoreceptor and image forming apparatus - Google Patents

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 in which a photoconductive layer and a surface layer made of hydrogenated amorphous silicon carbide are laminated on a conductive substrate.

[0002]

2. Description of the Related Art An electrophotographic photosensitive member mounted on an image forming apparatus such as an electrophotographic copying machine or a printer has electrophotographic characteristics, that is, potential characteristics such as charging ability, photosensitivity, and residual potential, and image density and image density. It is required to have good image characteristics such as resolution, contrast, gradation, etc., as well as excellent stability, durability such as abrasion resistance, printing durability, environmental resistance, and chemical resistance. . In order to realize such excellent characteristics, the surface layer formed on the photoconductive layer plays a large role.

Various materials and layer configurations have been proposed for the surface layer. Amorphous silicon-based materials, in particular, amorphous silicon carbide containing carbon (C) (hereinafter, amorphous silicon carbide is referred to as a −SiC) has attracted attention because it has excellent electrical characteristics, optical characteristics, image characteristics, durability based on high hardness, and the like. And a
An electrophotographic photoreceptor in which an SiC surface layer and an amorphous silicon-based photoconductive layer (hereinafter, amorphous silicon is abbreviated as a-Si) is already in practical use.

As such an a-SiC surface layer, those in which the hardness and C content of the layer are specified have been proposed, and these will be described in detail below. According to JP-A-62-272275, a surface layer is coated on an a-Si-based photoconductive layer, and this surface layer is mainly composed of silicon (Si) and C, and further has oxygen (O).
-It is made of an amorphous material containing hydrogen (H) and fluorine (F), and has a dynamic indentation hardness of 300 to 1,000 kgf /
An electrophotographic photosensitive member having a size of mm ² has been proposed. The material of this surface layer is a-Si _1-x C _x (H, F, O) (0 <x <
1), the dynamic indentation hardness of the surface layer is 1,000
When becomes kgf / mm ² or more, is high Si content in the surface layer, more susceptible to chemical effects, likely to generate the image defect in high humidity, whereas, at a 300 kgf / mm ² or less The C content in the surface layer increases, the photoconductivity deteriorates, the residual potential increases, and the hardness is considerably reduced. More likely to occur. Therefore, by limiting the dynamic indentation hardness of the surface layer to the above range, it is possible to obtain an electrophotographic photoreceptor excellent in moisture resistance and printing durability without image defects even in a high humidity atmosphere. Things.

Japanese Patent Application Laid-Open No. 63-81366 discloses an electrophotographic photosensitive member in which a protective layer formed of an amorphous material containing at least Si and C is provided on a photosensitive layer containing selenium (Se). Has been proposed. Materials for this protective layer include:
A-Si _1-x C _x with limited composition ratio (x = 0.4 to 0.99)
Is selected, and its hardness is Vickers hardness of 1,000 to 3,
000, and the film thickness is 50Å to 2 μm. And
The Se-based electrophotographic photoreceptor having the above-described structure has excellent durability and weather resistance, can obtain a clear copy without white stripes, and can be easily handled.

Japanese Patent Application Laid-Open No. 60-135955 discloses a-Si
A protective film made of an a-Si film containing nitrogen (N) atoms or C atoms is formed on the film, and the protective film has a non-uniform distribution in which the concentration of N atoms or C atoms increases on the surface side of the protective film. A configuration has been proposed. With this configuration, no interface potential is formed at the interface between the a-Si film and the protective film due to the addition of N atoms or C atoms, so that no residual potential is formed. As a result, a highly sensitive photoreceptor film is formed. can get.

Further, JP-A-60-169854 discloses that a photoconductive layer containing a-Si as a main component and a-Si
(N,
An electrostatic latent image carrier has been proposed in which a surface layer containing (C, O) is sequentially laminated, and the content of the substance is reduced on the support side and increased on the surface side. In addition, the content of the insulating material is preferably 0.01 to 30 atomic% on the support side and 1 to 90 atomic% on the surface side, and the thickness of the surface layer is 0.1%.
It is about 01 to 2 μm. According to such a surface layer, the ability to retain surface charges is improved without lowering the photosensitivity, and the mechanical strength of the surface is also improved.

Japanese Patent Application Laid-Open No. 61-130951 discloses that a blocking layer, a photoconductive layer and a surface coating layer composed of a-Si are sequentially laminated on a support, and the surface coating layer is composed of C and N. And a photoconductive member whose concentration continuously changes from the photoconductive layer side to the other side has been proposed. Such a surface coating layer comprises C and N on the free surface side.
Is formed to a content of about 10 to 40 atomic%, whereby delamination does not occur at the interface with the photoconductive layer, and the occurrence of image density unevenness due to the interference effect can be prevented, and a clear image can be obtained. Can be

Further, Japanese Patent Application Laid-Open No. 62-258466 discloses that a photosensitive layer and a surface layer are provided on a support, and the surface layer contains Si atoms as a base and contains C atoms. There has been proposed a light receiving member having a concentration distribution such that the concentration increases toward the free surface side from the beginning. In addition, the surface layer has a distribution concentration of C atoms in the layer direction of a minimum value of 0.5 at% and a maximum value of 95 at%, and a layer thickness of 0.003 to 30 μm.
m, thereby improving moisture resistance, continuous repetitive use characteristics, use environment characteristics, durability, and the like, and can stably and repeatedly obtain high-density, high-resolution, high-quality images.

[0010]

However, in the electrophotographic photosensitive members proposed in the above publications, a-S
Even if an iC-based surface layer is provided, an image defect called image deletion occurs when the image forming apparatus is mounted on an electrophotographic image forming apparatus and printing is performed under a high humidity environment. was there.

This image flow is caused by discharge products such as nitrate ions and ammonium ions generated by corona discharge being adsorbed on the surface layer and absorbing water in the atmosphere under a high humidity environment, or By oxidation of the Si atoms located on the surface of the surface by corona discharge, the hydrophilicity of the surface is increased and the hygroscopicity is increased, so that the electric resistance of the surface layer is reduced. In this case, the charge of the electrostatic latent image formed on the surface is moved toward the surface and the pattern of the electrostatic latent image is not maintained.

In order to prevent the occurrence of such image deletion,
A technique of heating a photoreceptor using a heater to disperse moisture adsorbed on a surface layer has been proposed and has already been put to practical use.

However, on the other hand, the charging ability of the photoreceptor is reduced, toner adheres to the surface of the photoreceptor, the power consumption of the image forming apparatus increases, and the design of the apparatus itself becomes complicated. There was a problem.

Therefore, in recent years, there has been a demand for an electrophotographic photoreceptor which is excellent in electrophotographic characteristics and durability, and which does not cause image deletion without heating the photoreceptor.

Accordingly, the present invention has been completed in view of the above circumstances, and an object of the present invention is to provide an electrophotographic photoreceptor in which image deletion does not occur even when printing is performed in a high humidity environment. It is in.

Another object of the present invention is to provide an image forming apparatus which does not require heating of a photosensitive member and achieves low cost.

It is still another object of the present invention to provide a long-life and long-term reliable electrophotographic photosensitive member capable of printing more than 300,000 times.

[0018]

The electrophotographic photoreceptor of the present invention comprises a photoconductive layer and a hydrogenated amorphous silicon carbide on a conductive substrate (hereinafter, hydrogenated amorphous silicon carbide is abbreviated as a-SiC: H). Are sequentially laminated, and the element ratio of the surface layer is further determined by the composition formula a.
-Si _1-x C _x : When expressed as H, the x value is 0.95 ≦ x
<1.00, and in order to appropriately polish the surface layer, the dynamic indentation hardness of the surface layer is gradually reduced from the interface side with the photoconductive layer toward the free surface side. The target indentation hardness is 45 to 220 kgf / mm ² .

[0019]

In another electrophotographic photoreceptor of the present invention, a photoconductive layer and a surface layer are sequentially laminated on a conductive substrate, and a first layer region in which the surface layer is disposed on the photoconductive layer side; A-SiC: H thickness of 700 to 4.0, disposed on the free surface side
In order to appropriately polish the surface layer, the element ratio of the second layer region is determined by the composition formula a-Si _1-x
C _x : when expressed as H, the x value is 0.95 ≦ x <1.00
And the dynamic indentation hardness is 45 to 220 kg
f / mm2.

An image forming apparatus according to the present invention is provided with the electrophotographic photosensitive member according to the present invention and has a printing durability 1 for the surface layer.
It is characterized in that the shaving amount per 10,000 sheets is 25-100 °.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a typical layer structure of an electrophotographic photosensitive member (i) of the present invention. In the figure, 1 is a conductive substrate, 2 is a photoconductive layer, and 3 is a surface layer.

According to the present invention, the surface layer 3 is made of a-SiC:
H, and the element ratio is represented by the composition formula a-Si _1-x C
_x : When expressed as H, the value of x is 0.95 ≦ x <1.00,
Preferably, 0.96 ≦ x <0.98, and the dynamic indentation hardness of the free surface is 45 to 220 kgf / mm ² .

By setting the x value to 0.95 or more, the hardness becomes small and the surface is easily shaved, and a fresh surface always appears. By setting the x value to less than 1, the dynamic indentation hardness becomes 45 kgf / mm ² or more, and a decrease in electrical characteristics can be prevented.

The dynamic indentation hardness of the free surface is 45
２２０220 kgf / mm ² , preferably 50-200 kgf
/ Mm ² , optimally 60 to 150 kgf / mm ² . And compared with the conventional a-SiC: H surface layer,
Since the hardness is 220 kgf / mm ² or less in terms of dynamic indentation hardness, the surface is appropriately polished by a cleaning means or the like for each copying process to remove discharge products or the like adsorbed on the surface of the surface layer. On the other hand, by setting the hardness to 45 kgf / mm ² or more in terms of dynamic indentation hardness, the shaving amount due to polishing in each copying process does not become too large, and compared with the conventional a-SiC: H surface layer. Its life is never extremely short.

Incidentally, the dynamic indentation hardness of the conventional a-SiC: H surface layer is about 350 to 600 kgf / mm ² , and by setting it in such a range, the durability is improved and the blades and the like are not damaged. I was trying not to stick.

The dynamic indentation hardness is such that the film thickness is 10 μm.
It is an effective hardness evaluation method to evaluate the hardness of the following thin film, applying a test load with a triangular pyramid-shaped indenter on the surface of the thin film, measuring the indentation depth of the indenter at that time, further calculating This is the required hardness. In the present invention, an ultra-micro hardness tester DUH-201 manufactured by Shimadzu Corporation was used.

The conductive substrate 1 has aluminum (A)
l) or SUS, Zn, Cu, Fe, Ti, Ni,
A conductive material such as a metal material such as Cr, Ta, Sn, Au, or Ag, or an alloy thereof, or a conductive film made of the above metal or a transparent conductive material such as ITO or SnO _{2 on} the surface of a resin, glass, or ceramics Formed by vapor deposition or the like and subjected to a conductive treatment. In particular, when an Al alloy material is used, the cost can be reduced and the weight can be reduced. In addition, when an a-Si-based material is used for the photoconductive layer 2 and a carrier injection blocking layer to be described later, the use of the Al alloy material can reduce the cost. This is preferable in that the adhesion is improved and the reliability is improved.

The photoconductive layer 2 is made of a-Si or a-Se such as a-Se or Se-Te.As ₂ Se _3.
A system, or a II-VI group compound such as ZnO.CdS.CdSe, a material obtained by granulating these and dispersing them in a resin, and a photoconductor material such as an OPC system can also be used. Above all, a-Si or C in a-Si
・ Using an a-Si material of an alloy to which N / O is added can stably obtain excellent electrophotographic characteristics such as high photosensitivity, high-speed response, repetition stability, heat resistance, and durability. In addition, it is preferable in that it has excellent compatibility with the a-SiC: H surface layer 3.

Such a-Si-based materials include a-Si.a
-SiC.a-SiN.a-SiO.a-SiGe.a
-SiCN ・ a-SiNO ・ a-SiCO ・ a-SiC
NO and the like. These include, for example, glow discharge decomposition method, various sputtering methods, various evaporation methods, ECR method,
A film is formed by a photo CVD method, a catalytic CVD method, a reactive vapor deposition method, or the like. In forming the film, hydrogen (H) or a halogen element (F · Cl) is used for terminating a dangling bond in the film by 1 to 40 atoms. %. Further, in order to obtain desired characteristics such as electrical characteristics such as dark conductivity and photoconductivity of each layer and an optical band gap, the periodic table IIIa
The above characteristics are adjusted by containing a group III element (hereinafter abbreviated as group IIIa element) or a group Va element (hereinafter abbreviated as group Va element), or by adjusting the content of elements such as C / N / O. I do.

As the above-mentioned IIIa element and Va group element,
Boron (B) and phosphorus (P) are preferable in that they each have excellent covalent bonding properties and can change semiconductor characteristics sensitively, and furthermore, provide excellent photosensitivity. And CN
・ When it is contained together with an element such as O, the group IIIa element
0.1 to 20,000 ppm is good, and Va group element is 0.1 to 10,000 pp
m is good, and when elements such as C / N / O are not contained or contained in trace amounts, the group IIIa element is 0.01 to
It is preferable to contain 200 ppm and a group Va element in an amount of 0.01 to 100 ppm. These elements may be provided with a gradient in the layer thickness direction, in which case the average content of the entire layer may be within the above range.

Further, the a-Si-based material may include microcrystalline silicon (μc-Si). When the a-Si-based material includes this μc-Si, the dark / photoconductivity can be increased. There is an advantage that the degree of freedom in designing the conductive layer 2 is increased.
Such μc-Si can be formed by employing the same forming method as described above and changing the film forming conditions. For example, in the glow-discharge decomposition method, it can be formed by setting the substrate temperature and the high-frequency power higher, and increasing the flow rate of hydrogen as a diluent gas. Further, even when μc-Si is contained, the same impurity element as described above may be added.

The thickness of the photoconductive layer 2 is appropriately set depending on the photoconductive material used and desired electrophotographic characteristics.
When an a-Si material is used, it is usually 5 to 100 μm,
It is preferably 15 to 80 μm.

Thus, the electrophotographic photoreceptor (i) having the above structure
According to the above, the surface layer 3 is composed of a-SiC: H, the element ratio of which is the composition formula a-Si _1-x C _x : H and the x value is 0.95 ≦ x <1.00, By setting the dynamic indentation hardness of the free surface to 45 to 220 kgf / mm ² ,
While maintaining its own durability, various adhering substances adsorbed on the surface of the surface layer or oxidized and deteriorated portions of the surface are removed, and a fresh surface can be always secured. , And image deletion in a high humidity environment can be prevented.

In the electrophotographic photoreceptor (i) having the above-described structure, the H content of the surface layer 3 is preferably about 1 to 70 atomic%, but if the H content is reduced within this range, Si— H bonds are reduced, and the generation of Si oxide generated on the surface of the surface layer 3, that is, SiO having high hydrophilicity can be suppressed, the ozone resistance of the surface layer 3 is improved, and the effect of preventing image deletion is generated. Is preferable because it can further increase the According to the findings of the present inventor, when the H content is about 18 atomic% or less, better results tend to be obtained.

The formation of the a-SiC: H surface layer 3 can be carried out in the same manner as described above for the a-Si-based photoconductive layer. Since hardness is not uniquely determined by its composition, it is important to appropriately set the manufacturing conditions.

For example, silane gas (SiH
₄ ) In the case of producing by a glow discharge decomposition method using a Si-containing gas such as a gas such as methane gas (CH ₄ ) and a C-containing gas, the ratio of the C-containing gas to the Si-containing gas is increased, or When the gas pressure during film formation is increased, the hardness tends to decrease. Also, when the dilution ratio of the source gas with the hydrogen gas is increased, the discharge power is increased, or the substrate temperature is increased, the hardness tends to increase.

The inventor conducted various experiments by glow discharge decomposition using SiH ₄ gas and CH ₄ gas. As a result, the ratio of CH ₄ / SiH ₄ gas was increased to 95% or more, and the dilution ratio with H ₂ gas was increased. To 0% to 50%, and the gas pressure during film formation to 0.25%.
13.56 MHz or 13.56 MHz at 1 k to ~ 0.50 Torr
High-frequency power pulse-modulated at 100 Hz per photoconductor
~ 250W and substrate temperature 220 ~ 300 ℃
It has been found that when the content is set to a degree, an a-SiC: H layer suitable for the surface layer 3 can be obtained.

Then, as described above, SiH ₄ gas and CH
_Although not limited to the _four gases, when forming the surface layer 3 by the glow discharge decomposition method, if pulse-modulated high-frequency power is used, a fresh gas is always used as a source gas existing in the discharge film formation region. (Unreacted gas) is sufficiently supplied and such unreacted gas is decomposed and subjected to a film forming reaction, so that the film forming speed of the surface layer 3 is increased and desired electrophotographic characteristics are maintained. It has been found that the H content of the surface layer 3 can be reduced while the Si-H bonds of the surface layer 3 are reduced as described above, and the effect of preventing image deletion can be further enhanced. .

The conditions for such high-frequency power pulse modulation are not limited to the above, and according to the knowledge of the present inventors, the frequency of the high-frequency power is 1 MHz to 50 MHz.
In z, the modulation cycle of the pulse modulation is appropriately set within the range of 50 Hz to 100 kHz according to the film forming apparatus, film forming conditions, and desired surface layer characteristics.

The thickness of the surface layer 3 is 0.4 to 1.2.
μm, preferably 0.5 to 0.8 μm. If the thickness is less than 0.4 μm, the durability becomes insufficient,
An image defect such as a streak tends to occur in the image with an increase in the number of endurable prints. When the image thickness exceeds 1.2 μm, the residual potential increases and image fogging and the like tend to occur.

Furthermore, a transition layer in which the C content of a-SiC: H is smaller than the C content of the surface layer 3 may be provided between the photoconductive layer 2 and the surface layer 3. The C content may be varied within the layer to provide a content gradient. By providing such a transition layer, the movement of the photocarriers generated in the photoconductive layer 2 becomes smooth, the photosensitivity is increased, the residual potential is reduced, and the image characteristics are also improved. The thickness of this transition layer is 1 μm or less, preferably 0.1 μm.
About 05 to 0.5 μm is good.

Next, another electrophotographic photosensitive member (ii) of the present invention is shown in FIG. The same layers as those of the electrophotographic photosensitive member (i) in FIG. 1 are denoted by the same reference numerals.

According to the electrophotographic photoreceptor (ii), a carrier injection blocking layer 4 is provided between the conductive substrate 1 and the photoconductive layer 2 as compared with the electrophotographic photoreceptor (i). An a-SiC: H surface layer 3 is formed on the conductive layer 2.

Various materials can be used for the carrier injection blocking layer 4 depending on the material of the photoconductive layer 2. If the photoconductive layer 2 is made of an a-Si material, the carrier injection blocking layer 4 can be used. When an a-Si-based material is used for the layer 4 as well, excellent adhesion between the conductive substrate 1 and the photoconductive layer 2 and excellent electrophotographic characteristics can be obtained.

When the a-Si-based carrier injection blocking layer 4 is provided, a larger number of a-Si-based photoconductive layers 2 are provided.
It is advisable to adjust the conductivity type by including a group IIIa element or a group Va element, or to increase the resistance by including a large amount of C.N.O.

As an electrophotographic photoreceptor other than the electrophotographic photoreceptor (ii) having the above-described structure, instead of the carrier injection blocking layer 4, exposure light of long-wavelength light is reflected on the surface of the conductive substrate 1, thereby recording. In order to prevent the occurrence of interference fringes in the image, a long wavelength light absorbing layer may be provided. Alternatively, a carrier excitation layer for increasing photosensitivity may be further provided between the photoconductive layer 2 and the surface layer 3 or between the photoconductive layer 2 and the transition layer.

Further, as an electrophotographic photoreceptor other than the above electrophotographic photoreceptors (i) and (ii), a-S
The hardness of the iC: H surface layer may be gradually reduced from the interface side with the photoconductive layer 2 toward the free surface side, and other layer configurations may be the same.

That is, when the hardness of the a-SiC: H surface layer 3 is gradually decreased from the interface side with the photoconductive layer 2 toward the free surface side, such an electrophotographic photosensitive member is used. In the early stages of using the body, the surface layer 3
The discharge products that have entered the fine concave-convex concave portions present on the surface of the surface can be removed by flattening the concave-convex portions, and as printing is performed, the convex portions are gradually removed. The irregularities themselves become smaller, which makes it easier to remove the discharge products adsorbed on the surface, which in turn increases the hardness of the surface layer, thereby reducing the amount of shaving due to polishing and preventing damage to the surface can do. In addition, excellent electrophotographic characteristics can be maintained for a long period of time.

To change the hardness in this way, for example, when forming a film by glow discharge decomposition,
From the interface side with the photoconductive layer 2 toward the free surface side, the ratio of the C-containing gas to the Si-containing gas in the raw material gas is gradually increased to increase the C content, or the gas pressure during film formation is increased. Various means such as gradually increasing, gradually decreasing the dilution ratio of the source gas with hydrogen gas, gradually decreasing the discharge power, gradually decreasing the substrate temperature, or combining these conditions may be employed.

Thus, with this configuration, it is possible to more effectively prevent image deletion occurring in the early stage of use, and to obtain a high-reliability, long-life, high-quality electronic device that does not cause image deletion or image streaking even when used for a long period of time. It becomes a photoreceptor.

Next, another electrophotographic photoreceptor (iii) of the present invention
(iv) will be described with reference to FIGS. In these drawings, the same layers as those in FIGS. 1 and 2 are denoted by the same reference numerals.

In the electrophotographic photoreceptors (iii) and (iv), a
A surface layer 5 made of -SiC: H comprises a first layer region 6 disposed on the photoconductive layer 2 side and a second layer region 7 disposed on the free surface side. The thickness of the second layer region 7 is 700 to
The second layer region 7 has a thickness of 4,000, preferably 800 to 3,000, and most preferably 1,000 to 2,000. In such a range, the entire image itself is not scraped, so that image deletion does not occur, and since it is not too thick, there is no deterioration in light transmittance and no residual potential is generated.

As for the second layer region 7, similarly to the surface layer 3, when the composition formula is expressed as a-Si _1-x C _x : H, the x value is 0.95 ≦ x <1.00. The dynamic indentation hardness of the free surface is 45 to 220 kgf / mm ² .

With this configuration, the conventional a-
Compared with the SiC: H surface layer, its hardness is more than 45 kgf / mm ² in dynamic indentation hardness. Therefore, the surface is appropriately polished by a cleaning means or the like for each copying process, and is adsorbed on the surface of the surface layer. Of the discharged discharge products and the like, while the hardness is reduced by a dynamic indentation hardness of 22.
By setting it to less than 0 kgf / mm ^{2, the} shaving amount due to polishing in each copying process does not become too large, and the life thereof does not become extremely short as compared with the conventional a-SiC: H surface layer. .

The thickness of the second layer region 7 is 700 to
By setting the temperature to 4,000 ° (0.07 to 0.3 μm), excellent durability can be ensured, and further, an increase in the residual potential can be suppressed. As a result, excellent electrophotographic characteristics can be obtained. If the thickness of the second layer region 7 is less than 700 °, the withstand voltage and durability become insufficient, and the life of the photoconductor tends to be shorter than the life of the image forming apparatus due to wear.
On the other hand, when the thickness of second layer region 7 exceeds 4,000 °, the residual potential increases.

For the first layer region 6, various materials other than the a-SiC material can be used. For example, a-Si
Amorphous silicon nitride (a-S
iN) ・ amorphous silicon oxide (a-Si)
O) Amorphous silicon oxycarbide (a-S)
A high resistance material such as iCO) / amorphous silicon oxynitride (a-SiNO) may be used. Each of these layers is formed by the same thin film forming means as that of the a-Si based photoconductive layer 3 and the like. In forming the film, H or halogen (F.Cl) is used for terminating dangling bonds or adjusting hardness. It is good to make it contain 1-160 atomic% in it.

In the case where the first layer region 6 is formed by a-SiC: H film formation, the C content is made smaller than that of the second layer region 7 and the compositional formula is a-Si1-x Cx: H. When this is done, it is preferable that the x value be in the range of 0.3 <x <0.95, preferably 0.6 <x <0.95, from the viewpoint of optimizing the high hardness characteristics and optical characteristics of this layer region. Further, these materials may contain a group IIIa element or a group Va element for adjusting electric characteristics.

Another material used for the first layer region 6 is Ta _2, which is a high-resistance antioxidant film having excellent wear resistance.
O ₅ or _{Si 3 O 4 · SiC · BN} · Al 2 O 3 · Cr 2
O ₃ and others. By forming layers of these materials by RF sputtering, DC sputtering, reactive sputtering, RF magnetron sputtering, DC magnetron sputtering, etc., they show excellent adhesion and denseness. .

When the first layer region 6 is formed from a resin material, the resin material may be PTFE (polytetrafluoroethylene), POM (polyacetal), styrene, olefin, polyamide, or the like. Or a mixed resin thereof. Alternatively, polyimide or polyethylene terephthalate / polypropylene / methacryl / polyethylene / polyester / nylon / acetal / fluororesin / ABS resin / polyester / polycarbonate / polymethylpentene / polystyrene / AAS resin may be used.

The thickness of the first layer region 6 is from 4,000 to 10,000Å
(0.4 to 1.0 μm), preferably 5,000 to 8,000 mm. If the thickness is less than 4,000 mm, the durability becomes insufficient, and defects such as streaks appear on the image as the number of prints increases. On the other hand, when the temperature exceeds 10,000 °, the residual potential becomes high, and defects such as image fogging tend to occur. Therefore, by setting the thickness of the first layer region 6 within the above range, a long life and high durability can be maintained, and a highly reliable electrophotographic photosensitive member can be obtained.

Thus, the electrophotographic photoreceptor (iii) having the above structure
According to (iv), various adhering substances adsorbed on the surface of the second layer region 7 of the surface layer 5 can be removed, a fresh surface can be always secured, durability can be secured, and residual It was possible to suppress the increase in the potential, and as a result, it became unnecessary to heat the photosensitive member, and it was possible to prevent image deletion in a high humidity environment.

Each of the above-described electrophotographic photosensitive members (i) and (ii)
Regarding (iii) and (iv), it was found that when the ten-point average roughness of the initial state of the surface layers 3 and 7 was set to 2,000 ° or less, image deletion would not occur even after repeated printing for a long time. did.

That is, the surface layers 3 and 7 have irregularities in the initial state, and the irregularities are reduced by the surface polishing accompanying the printing durability. On the other hand, the progress rate of the surface oxidation tends to be slow. Therefore, it was confirmed that when the ten-point average roughness of the surface layers 3 and 7 in the initial state exceeds 2,000 °, the progress speed of such surface oxidation becomes relatively fast and image deletion occurs.

If the ten-point average roughness of the surface layers 3 and 7 in the initial state is set to 2,000 ° or less, preferably 1,800 ° or less, even if the printing durability of 300,000 times or more is performed, the image deletion It has also been found that when the ten-point average roughness is set to 200 ° or less during 300,000 printings, image deletion does not occur in the previous printing.

[0066]

EXAMPLES Specific examples of the electrophotographic photosensitive member of the present invention will be described below. However, the present invention is not limited to the following embodiments at all, and various changes and improvements may be made without departing from the scope of the present invention.

Example 1 A conductive substrate 1 was prepared by mirror-finishing and cleaning the outer peripheral surface of a drawing tube made of an aluminum alloy having an outer diameter of 30 mm and a length of 254 mm, and this was used for a glow discharge decomposition film forming apparatus. The carrier injection blocking layer 4, the photoconductive layer 2, and the surface layer 3 are sequentially laminated under the film forming conditions shown in Table 1, and the electrophotographic photosensitive member A (electrophotographic photosensitive member A (ii) shown in FIG. Hereinafter, referred to as a photoconductor A). The surface layer shows the film forming conditions at the interface layer with the photoconductive layer 2 and the film forming conditions on the free surface side, and the film formation between them changes the gas flow rate and the film forming speed gradually.

[0068]

[Table 1]

As a comparative example, the carrier injection blocking layer 4 and the photoconductive layer 2 were sequentially laminated under the film forming conditions shown in Table 2,
Further, an a-SiC: H surface layer was laminated to prepare an electrophotographic photosensitive member B (hereinafter, referred to as photosensitive member B).

[0070]

[Table 2]

Regarding the surface layers of the photoconductors A and B,
A part of each of the interface with the photoconductive layer 2 and the free surface is 5
The composition was determined by XPS analysis (X-ray photoelectron spectroscopy), and the dynamic indentation hardness at the interface between the free surface and the photoconductive layer 2 was measured for the surface layers of the photoconductors A and B. , Ultra-micro hardness tester (DUH- manufactured by Shimadzu Corporation)
201), the results shown in Table 3 were obtained.

[0072]

[Table 3]

Each of the photoconductors A and B thus obtained was mounted on an electrophotographic printer (FS-1550 manufactured by Kyocera), and a printing durability test of 300,000 sheets was performed. Evaluation was performed to evaluate / measure the state of occurrence of image deletion and image deterioration and also the amount of shaving of the surface layer. The results shown in Table 4 were obtained. In the case of a small-sized device such as the photoconductors A and B, the service life of 300,000 sheets is obtained, so that sufficient durability for practical use can be obtained.

For the evaluation of image deletion, first, the heater for heating the photoconductor was removed from the electrophotographic printer, and the electrophotographic printer was mounted on the photoconductors A and B.
In high temperature and high humidity environments (32
(85 ° C., 85% RH) for 8 hours, after which an image was formed to evaluate the occurrence of image deletion. Further, image deterioration such as occurrence of image flaws was also evaluated.

[0107] The case where no image deletion or image deterioration is observed is indicated by a circle, the case where slight occurrence is observed is indicated by a triangle, and the case where practically any trouble is observed is indicated by a cross.
Indicated by a mark.

[0076]

[Table 4]

As is clear from the above results, according to the photoreceptor A of the present invention, no image deletion or image deterioration was observed, and a recorded image of good image quality was always obtained. In addition, there were no problems such as a decrease in image density, occurrence of fog, a decrease in contrast, and a decrease in resolution.

However, in the case of the photosensitive member B, the image deletion is observed after about 5,000 sheets of printing, and when the printing is further advanced, the image deletion occurs, which is a practical problem.

Further, with respect to the photoreceptor A of the present invention, the shaving amount of the surface layer 3 was 1,380 ° for a 300,000-printing plate, which was slightly larger than 880 ° of the photoreceptor B. No deterioration was observed in both characteristics and electrophotographic characteristics, indicating that sufficient durability was obtained by the present invention.

Further, the shaving amount of the surface layer of the photosensitive member A is about 16% of the thickness of the entire surface layer, and the shaving amount is gradually reduced. Therefore, it can be said that the photoconductor A has sufficient durability.

Further, in forming the surface layer of the photoreceptor A, a high-frequency power was pulse-modulated at 1 kHz and applied, and the other conditions were the same to prepare a photoreceptor A '.
The film forming rate on the free surface side of the surface layer of the photoconductor A ′ is 0.2
μm / hour, and the H content on the free surface side of the surface layer is further measured by a Fourier transform infrared spectrophotometer (5ZDX manufactured by Nicolet).
Was 15.0 atomic%. Also,
H content on the free surface side of the surface layer of photoconductor B is 74.0 atomic%
Met.

The same evaluation was performed on the photoreceptor A ′ thus obtained. The same good result as that of the photoreceptor A was obtained. It was confirmed that the flow could be prevented without requiring heating of the photoreceptor, and that it also had excellent durability.

[Example 2] In the same manner as in [Example 1], the carrier injection blocking layer 4 and the carrier injection blocking layer 4 were formed on a conductive substrate 1 made of an aluminum alloy and having an outer diameter of 30 mm and a length of 254 mm according to the film forming conditions shown in Table 5. The photoconductive layer 2 and the a-SiC: H surface layer 5 composed of the first layer region 6 and the second layer region 7 are sequentially laminated to form an electrophotographic photosensitive member as the electrophotographic photosensitive member (iv) in FIG. C (hereinafter, referred to as photoconductor C) was prepared.

[0084]

[Table 5]

Further, as a comparative example, the carrier injection blocking layer 4 and the photoconductive layer 2 were sequentially laminated under the film forming conditions shown in Table 6, and an a-SiC: H surface layer was further laminated to form an electrophotographic photosensitive member D ( Hereinafter, referred to as a photoconductor D).

[0086]

[Table 6]

Each composition of the first layer region 6 and the second layer region 7 of the surface layer 5 of the photoconductor C and the surface layer of the photoconductor D
The x value was calculated in the same manner as in [Example 1], and the dynamic indentation hardness on the free surface was measured.
The result shown in FIG.

[0088]

[Table 7]

Then, for the photoconductors C and D, [Example 1]
The results shown in Table 8 were obtained by examining the image flow, image deterioration, and shaving amount in the same manner as in.

[0090]

[Table 8]

From the above results, it can be seen that according to the photoreceptor C of the present invention, no image deletion or image deterioration was observed, and a recorded image of good image quality was always obtained. In addition, there were no problems such as a decrease in image density, occurrence of fog, a decrease in contrast, and a decrease in resolution. On the other photoconductor D, 5,
The occurrence of image deletion was observed when about 000 sheets of printing were performed, and it was found that the image deletion occurred to some extent in practical use when printing was further advanced.

Further, in the photoreceptor C of the present invention, the shaving amount of the second layer region 7 of the surface layer 5 is 1,650 mm after 300,000 sheets of printing.
Although it was slightly larger than 880 ° of the photoconductor D of the comparative example, no deterioration was observed in the image characteristics and electrophotographic characteristics similarly to the photoconductor A of [Example 1], and the photoconductor C was It has sufficient durability.

Further, since the first layer region 6 having high hardness exists below the second layer region 7 of the photosensitive member C, and the shaving amount of the second layer region 7 is gradually reduced. It can also be seen that the photoreceptor C has sufficient durability so that there is no particular problem even when printing is further performed.

Thus, it can be seen that the photosensitive member C of the present invention can also prevent image deletion in a high-humidity environment without requiring heating of the photosensitive member, and has excellent durability.

[Example 3] In producing the photoreceptor C of the present invention in the same manner as in [Example 2], an electron beam having various thicknesses of the second layer region 7 was formed by changing the film formation time of the second layer region 7. Photoconductors E to M were prepared, and the image deletion was evaluated for them in the same manner as in [Example 1]. In addition, when the characteristics of the photoreceptor were evaluated as follows, the results shown in Table 9 were obtained.

Evaluation of photoreceptor characteristics: The charging ability, photosensitivity, and residual potential were measured using a potential characteristic tester. Regarding the charging ability, it is preferable that the surface potential is 300 V or more when charged by applying a drum current of 65 μA, and the photosensitivity is to change the surface potential from 300 V to 50 V by exposure at a wavelength of 660 nm.
Exposure required to lower the voltage to 0.3 V or less is 0.3 lux · sec or less.
Surface potential of 3 by exposure at nm / exposure 0.65 lux · sec
Those which fell from 00V to 15V or less were regarded as good. Then, all of the characteristics were good, and a mark was given when any one of them was defective.

[0097]

[Table 9]

As is clear from the results in Table 9, the photosensitive member J
In K / L, both image characteristics and photoconductor characteristics are good. The residual potential of the photoconductor M is high because the thickness of the second layer region is large.

[Example 4] In the same manner as in [Example 2], when producing the electrophotographic photoreceptor of the present invention, under the conditions for forming the second layer region 7, the H ₂ gas flow rate was varied as shown in Table 10. In addition to performing the gas dilution and changing the RF power, the photosensitive members N to T having different dynamic indentation hardness are manufactured.
Each of the photoconductors N to T was evaluated for image deletion and image deterioration in the same manner as in [Example 1]. Further, the x value in the second layer region 7 and the shaving amount at the end of 10,000-sheet printing were measured. The result as shown in FIG.

[0100]

[Table 10]

As shown in Table 10, the photosensitive member P of the present invention
In S, good results were obtained for image deletion and image deterioration.

When the shaving amount is less than 25 mm per 10,000 printing sheets, the discharge products cannot be completely removed and image deletion occurs. On the other hand, when the shaving amount exceeds 100 mm, the surface of the photosensitive member is excessively shaved. Since a streak is generated, good results can be obtained if the shaving amount per 10,000 sheets of printing durability is in the range of 25 to 100 °. And about the thickness,
750 mm for photoreceptor with 25 mm shavings from machine life
Film thickness of 3,000 for photoreceptors with abrasion of 1,000 mm
Since a film thickness of Å is required, the thickness of the second layer region 7 is 800
It is set in the range of ~ 3,000Å.

[Example 5] In producing the photoconductor A of [Example 1], the film forming conditions on the free surface side of the surface layer 3 were set to H.
_{2 While} diluting by changing the gas flow rate in many ways,
By changing the gas pressure and the RF power as shown in Table 11, photoreceptors having different dynamic indentation hardness were prepared, and
Image deletion and image deterioration were evaluated in the same manner as in [Example 1], and the x value and dynamic indentation hardness on the free surface side were measured. The results shown in Table 11 were obtained.

[0104]

[Table 11]

As shown in Table 11, in the photoconductors of the present invention, good results were obtained with respect to image deletion and image deterioration.

[Example 6] In manufacturing the photoconductor A of [Example 1], the film forming conditions on the free surface side of the surface layer 3 were set to H.
_{2 While} diluting by changing the gas flow rate in many ways,
The photoreceptors ヲ to ナ were prepared by changing the gas pressure, the RF power, and the temperature (substrate temperature) as shown in Table 12, and changing the presence or absence of pulse modulation at 1 kHz with respect to the RF power. The table also shows the measurement results of the hydrogen (H) content in the surface layer.

[0107]

[Table 12]

With respect to the photoconductors ヲ to ナ, image running and image deterioration were evaluated when a 10,000-sheet printing durability test was performed in the same manner as in [Example 1]. Each evaluation was performed five times. In the case of the photoreceptor of No. 5, the occurrence of image deletion and image deterioration was not recognized at all five times.

Next, the environmental conditions were set to 35 ° C./90% RH.
Image deletion and image deterioration were evaluated under the same conditions as above, and each evaluation was performed five times.
The results as shown in Table 13 were obtained. In the table,
The numerical value in the right column of “/” indicates the number of evaluations 5 and the numerical value in the left column indicates the number of occurrences.

[0110]

[Table 13]

As is clear from the results shown in Table 13, RF
When pulse modulation is performed on the electric power, the H content in the surface layer tends to decrease, and the evaluation result of the image deletion is improved accordingly. Particularly good results were obtained with the photoreceptor having an H content of about 18 atomic% or less.

[Example 7] Next, with respect to the photoconductors A and B of [Example 1], the ten-point average roughness of the surface layer 3 in the initial state was measured.
In the same way, a printing durability test of 300,000 sheets was performed at 1,000 mm, and an image evaluation was performed at each stage during the printing durability to determine the occurrence of image deletion and image deterioration, and also the ten-point average roughness Rz. As a result of evaluation / measurement, the results shown in Table 14 were obtained.

[0113]

[Table 14]

As is clear from the results in the table, according to the photoreceptor A of the present invention, since the hardness of the surface layer is small, the photoreceptor A is smoothened by repeating printing.

Further, with respect to the photosensitive member A of [Example 1], the ten-point average roughness Rz (unit Å) of the surface layer 3 was changed in various ways as shown in Table 15, whereby the photosensitive members a to g were changed. It was fabricated and its initial ten-point average roughness was measured for the influence of image bleeding. The results shown in the table were obtained.

In order to change the ten-point average roughness Rz (unit に) as described above, the cutting tool shape (Miracle, 10R, 5R manufactured by Tokyo Diamond Tool), the cutting tool feed speed,
Adjust the cutting speed and so on.

[0117]

[Table 15]

As is evident from the results shown in the table, according to the photoconductors a to e having the ten-point average roughness of 2,000 ° or less, no image deletion occurs even after 300,000 sheets of printing.

[Example 8] Photoconductors h to m (ten-point average roughness Rz of the surface layer 3: 1,00) produced in the same manner as the photoconductor A of [Example 1]
0 to 2,500 mm), 300,000 sheets were printed, the ten-point average roughness Rz at that time was measured, and the image deletion was also evaluated. Obtained.

[0120]

[Table 16]

As is evident from the results, it is understood that, in the photoconductors i to k having the ten-point average roughness of 200 ° or less, no image deletion occurs even after 300,000 sheets of printing.

[0122]

As described above, according to the present invention, by forming a surface layer made of a-SiC: H having a predetermined element ratio and dynamic indentation hardness, the durability of the surface layer can be maintained while maintaining durability. Various adhering substances adsorbed on the surface can be removed, a fresh surface can always be secured, and thereby, image flow in a high humidity environment can be prevented without requiring heating of the photoreceptor. As a result, it was possible to provide an electrophotographic photosensitive member having excellent durability.

Further, according to the present invention, the a-SiC:
By changing the hardness of the H surface layer so as to be gradually smaller from the interface side with the photoconductive layer toward the free surface side, it is possible to effectively remove discharge products in an initial stage, While reducing the amount of shaving by polishing,
It can prevent scratches on the surface, resulting in more effective prevention of image deletion in the early stage of use, and high image quality without image deletion and image streaking even during long-term use Thus, a highly reliable and long-lived electrophotographic photosensitive member could be provided.

Further, according to the electrophotographic photoreceptor of the present invention,
The surface layer is provided with a first layer region on the photoconductive layer side and a second layer region on the free surface side, and the second layer region is formed from a-SiC: H having a predetermined element ratio and dynamic indentation hardness and thickness. With excellent surface properties, it has excellent durability and excellent electrophotographic properties, and can prevent image deletion in a high-humidity environment without requiring heating of the photoreceptor. A photoreceptor could be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a layer configuration of an electrophotographic photosensitive member of the present invention.

FIG. 2 is a cross-sectional view illustrating another layer configuration of the electrophotographic photosensitive member of the present invention.

FIG. 3 is a cross-sectional view illustrating another layer configuration of the electrophotographic photosensitive member of the present invention.

FIG. 4 is a cross-sectional view illustrating another layer configuration of the electrophotographic photosensitive member of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Conductive substrate 2 ... Photoconductive layer 3 ... Surface layer 4 ... Carrier injection blocking layer 5 ... Surface layer 6 ... 1st layer area 7 ... ... Second layer area

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-214868 (JP, A) JP-A-62-272275 (JP, A) JP-A-60-14248 (JP, A) JP-A-2- 203350 (JP, A) JP-A-64-86149 (JP, A) JP-A-60-7433 (JP, A) JP-A-6-332197 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 5/00

Claims (3)

(57) [Claims] 1. A electrophotographic photosensitive member and the surface layer are sequentially stacked consisting photoconductive layer and the hydrogenated amorphous silicon carbide on a conductive substrate, the element ratio of the surface layer composition formula a-Si _1-x When the value of C _{x is} H, the value of x is 0.
95 ≦ x <1.00 and the surface layer is appropriately polished
Therefore, the dynamic indentation hardness of the surface layer is set to
The surface is gradually reduced from the surface side to the free surface side, and the dynamic indentation hardness of the free surface is 45 to 220 kgf / mm.
^2. An electrophotographic photoreceptor, wherein 2. An electrophotographic photoreceptor in which a photoconductive layer and a surface layer are sequentially laminated on a conductive substrate. Thickness 7 consisting of hydrogenated amorphous silicon carbide
A lamination of the second layer region of 00～4,000A, surface
In order to appropriately polish the layer, when the element ratio in the second layer region is represented by a composition formula a-Si _1-x C _x : H, the x value is 0.9.
An electrophotographic photosensitive member, wherein 5 ≦ x <1.00 and the dynamic indentation hardness is 45 to 220 kgf / mm ² . 3. A process according to claim 1 or claim 2 electrophotographic photosensitive member according ten-point average roughness of the initial state of the surface layer is equal to or less than 2,000 Å.