JPS62178975A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve durability by forming a surface protective layer of an amorphous layer essentially consisting of carbon atoms. CONSTITUTION:The surface coating layer 15 consists of the amorphous layer essentially consisting of the carbon atoms. The amorphous carbon layer has the tough bond between the carbon atoms and the layer itself has high strength to thermal and mechanical impact. Strong carbon-silicon bonding strength is generated at the interface and lattice bonding characteristic is improved if the amorphous carbon layer is deposited on an amorphous silicon layer. Since the amorphous carbon layer is hydrophobic, said layer prevents the adsorption of moisture. The durability is thereby improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an electrophotographic photoreceptor using an amorphous silicon-based photoconductive layer.

Electrophotographic photoreceptors using Ryosugi Arashi's amorphous silicon have properties equivalent to or better than photoreceptors using other photoconductive materials, and are also harmless to the human body and the environment. It has the following advantages.

However, the free surface of the amorphous silicon layer is very active and susceptible to developer components and atmospheric moisture. For example, there is a problem in that OH groups, oxygen atoms, hydrogen atoms, etc., which are constituent elements of water, diffuse into amorphous silicon, causing deterioration in the characteristics of the photoreceptor over time.

As a method to solve these problems, it has been proposed to provide a surface protective layer on the amorphous silicon layer.

For example, JP-A-57-56848 discloses that polyethylene terephthalate (PET), polycarbonate,
It has been proposed to form a surface coating layer using an organic insulator such as polyvinyl chloride. Also, JP-A-59-1
No. 47353 reports the use of an amorphous silicon layer containing oxygen, carbon, or nitrogen as a surface coating layer.

However, when organic insulators such as PET are used as a protective layer, their hardness is lower than that of amorphous silicon, so the original surface protection effect cannot be expected, and if we focus on wear resistance, for example, it will actually decrease. I end up. In addition, when amorphous silicon is made to contain oxygen, carbon, and nitrogen to form a surface coating layer, the hardness increases and wear resistance improves, but amorphous silicon is essentially highly active and hydrophilic. Since these still remain, the various properties of the photoreceptor deteriorate after long-term use.

OBJECTS OF THE INVENTION The present invention exhibits high stability over time without causing deterioration of various properties as an electrophotographic photoreceptor.

An object of the present invention is to provide an electrophotographic photoreceptor that exhibits high durability even when used repeatedly.

The electrophotographic photoreceptor of the present invention comprises a support, an amorphous silicon-based photoconductive layer provided on the support, and a surface protective film provided on the photoconductive layer. The photographic photoreceptor is characterized in that the surface protective layer is an amorphous layer containing carbon atoms as a main component.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a sectional view showing an example of the structure of the electrophotographic photoreceptor of the present invention, in which a photoconductive layer 13 and a surface coating layer 15 are sequentially laminated on a support 11.

As the support 11, metal materials such as Fe, Mo, and A1, inorganic materials such as quartz glass, and organic materials such as polyimide and polyester can be used. When the support is an insulator, it is desirable that at least its surface is subjected to conductive treatment.

Photoconductive layer 13 is formed from an amorphous silicon layer. It is appropriate that the amorphous silicon layer contains at least one type of atom selected from hydrogen atoms, halogen atoms, and deuterium atoms. By including these atoms, defects in the amorphous silicon layer are compensated for, and the movement of generated carriers is facilitated. Although it depends on the film forming conditions, it is preferable that these atoms be contained in the amorphous silicon in an amount of 5 to 40 atm (g)%.

The thickness of the amorphous silicon layer is suitably 5 to 30 μm, preferably 10 to 20 μm.

The amorphous silicon layer can be formed by a plasma CVD method, a glow discharge method, a sputtering method, or the like.

The surface coating layer 15 is an amorphous layer containing carbon atoms as a main component. This amorphous carbon layer preferably contains carbon as a main component and further contains at least one type of hydrogen atom, halogen atom, or deuterium atom. The resistance R of the amorphous carbon layer is 1×101s≦
A range of R<IX 1017 (Ω·cm) is suitable.

By containing these atoms, a so-called i-carbon film having a diamond-like structure in which C--C bonds are mainly SP1 bonds and containing -deuterium atoms etc. can be obtained. Although it depends on the manufacturing conditions, it is preferable that these atoms be contained in the amorphous carbon layer in an amount of 5 to 50 atm%, more preferably 10 to 40 atm%.
%. The amorphous carbon layer has very strong bonds between carbon atoms, and itself has the property of having high strength against thermal and mechanical impacts.

Furthermore, since carbon is a four-coordinate element like silicon, when an amorphous carbon layer is deposited on an amorphous silicon layer, strong bonding force between carbon and silicon is generated at the interface, resulting in good lattice bonding. . Regarding chemical properties, since the amorphous carbon layer is hydrophobic, it can effectively prevent moisture adsorption, which is the biggest cause of property deterioration of amorphous silicon-based photoconductive layers. moreover.

The amorphous silicon layer has excellent light transmittance over a wide range from 2250 nm at the absorption edge to 25 μm at the far infrared, and does not adversely affect the characteristics of the photoreceptor.

The thickness of the amorphous carbon layer is suitably 0.01 to 2 μm, preferably 0.1 to 1 μm.

The amorphous carbon layer is C, H4, C2H.

It can be formed by a low pressure CVD method using a gaseous carbon source such as a paraffinic hydrocarbon, a plasma CVD method, a high frequency ion blating method, or the like. Among these, when the substrate temperature is relatively low (for example, 30
(approximately 0° C. or lower), a plasma CVD method that can yield an amorphous carbon layer with good properties is suitable, and a high-frequency plasma method is particularly suitable.

The plasma used at this time is a weak electric field plasma, and in the plasma space, collisions between electrons and neutral molecules cause phenomena such as molecular excitation, dissociation, and ionization. Focusing on electrons in plasma space, their kinetic energy is extremely large compared to ions and neutral molecular species, and when converted to temperature, it is equivalent to tens of thousands of degrees, but the actual gas temperature is low. There are two effects that plasma has on chemical reactions.

One of them is the effect that neutral molecular species collide with high-energy electrons to become excited state molecular species, which relatively lowers the activation energy of the reaction and accelerates the reaction rate.

The other effect is that the neutral molecular species dissociates into atoms due to this collision, and this active species participates in the reaction, causing the reaction to proceed at a low temperature.

From the above-mentioned effects, an amorphous carbon layer can be formed at a low temperature by using the plasma CVD method, and the previously formed amorphous silicon layer will not be damaged. Furthermore, since a gaseous substance can be used as a starting material, it is easy to control the film thickness, and it is also possible to control the characteristics by incorporating impurities into the produced film.

Next, the method for manufacturing the electrophotographic photoreceptor of the present invention will be explained in more detail.

FIG. 2 is an explanatory diagram of a plasma CVD apparatus.

The vacuum chamber 23 is evacuated to a high vacuum by the exhaust system 21.

Next, the valves 31, 33, 35 are opened, the mass flow meter 37, 39, 41 is adjusted to a predetermined flow rate, and the gas component is introduced into the vacuum chamber from the gas cylinder 43, 45, 47, and the pressure in the vacuum chamber is increased. control.

As the raw material gas, for example, CnH2o+2 (n is an integer) and H2 can be used in combination, and
Combination of CoH2n+2+C, F2□2, Cm F
Similarly good results are obtained with the combination 211+2+H2. At this time, impurities can be contained by introducing a doping gas.

Next, high frequency power is applied to the electrode 53 by the high frequency power source 51, and an amorphous carbon film is formed on the amorphous silicon layer of the substrate 27 while rotating the substrate 27 by the motor 55. 29 is a heater for controlling the temperature of the substrate 27. Typical film deposition conditions are as follows.

Discharge voltage crab 0.01~1.0Torr Substrate temperature: 10
0 to 350°C High frequency electric crab 0.01 to 51/cd The amorphous silicon layer can be formed using the same device prior to the formation of the amorphous carbon layer.

Open valves 71, 73, 75 and mass flow meter 77
A Sig or H source such as 5iIL and a doping gas such as ○2 or B2H are introduced into the vacuum chamber from gas cylinders 83° 85 and 87 by controlling the flow rate with 83° and 87, and an amorphous silicon layer is formed by plasma CVD. form.

FIG. 3 is an explanatory diagram showing the ion blating device. The vacuum chamber 123 is evacuated to a high vacuum by the exhaust system 121. Next, open the valve 131 and turn off the gas cylinder 1.
A raw material gas such as a carbon source, hydrogen source, fluorine source, deuterium source, or doping gas is introduced from 43, and the pressure is adjusted. Next, high frequency power is applied from the high frequency power source 151 and DC voltage is applied to the electrode 153 simultaneously from the DC power source 152.
is applied to generate plasma, and the source gas ions generated in the plasma space are accelerated to collide with the substrate 127 to form an amorphous carbon film. Typical deposits are as follows.

Discharge voltage crab 0.005 to 1.0 Torr Substrate temperature = 5
0~300℃ High frequency electric crab 0.01~1011/cJ DC voltage: 1
00 to 2000 V The main point of the present invention is to use an amorphous carbon layer as a surface coating layer.

The photoconductive layer is not limited to those mentioned above. For example, a photoconductive layer can be formed by laminating P-type and N-type amorphous silicon layers.

According to the present invention, in an electrophotographic photoreceptor using an amorphous silicon-based photoconductive layer, by using an amorphous carbon layer as a surface protective layer, various characteristics as an electrophotographic photoreceptor are improved over time. Stable and highly durable,
An electrophotographic photoreceptor having high abrasion resistance can be obtained.

Example 1 Using the device shown in Fig. 2, 80 mmφ, length 30
An electrophotographic photoreceptor of the present invention was produced by high frequency plasma CVD using a 0nue cylindrical aluminum drum as a support.

A clean aluminum drum is fixed to a support jig inside a vacuum chamber, and the inside of the vacuum chamber is evacuated to high vacuum using an oil diffusion pump. Each gas component is introduced to form an amorphous silicon layer under the following conditions. This was used as a photoconductive layer.

Conditions for creating amorphous silicon layer Manufacturing method: High frequency plasma CVD method Raw material gas and flow rate: S x H4/A r (20%): 400SC
CMB 2H, / A r (100ppm): 4
SCCM02 (100%): 2SCCM Discharge voltage ITorr Substrate temperature: 250℃ High frequency output 75W High frequency frequency: 13.56MHz Film thickness: 20μ After forming the amorphous silicon layer, turn off the high frequency power and stop introducing the source gas did.

Next, the mixture was evacuated again to a high vacuum using an oil diffusion pump, and then a raw material gas for amorphous carbon was introduced until a predetermined pressure was reached, and an amorphous carbon layer was created under the following conditions to serve as a surface coating layer.

Manufacturing method of amorphous carbon: High frequency plasma CVD method Raw material gas: CH4 + H2 (5: 100) Discharge voltage: ITorr Substrate temperature: 200°C High frequency: 13.56 MHz Film thickness: 5000 Electrons obtained in this way The photographic photoreceptor was mounted in a copying machine and its characteristics were evaluated as follows. Positive charging is applied in the dark with a power supply voltage of 6 KV, image exposure is performed with a light intensity of 9.5 lux to form an electrostatic latent image, and then it is developed with a negatively charged toner and transferred and fixed onto transfer paper. did. As a result of repeating this image process and comparing the image on the first sheet of transfer paper and the image on the 50,000th sheet of transfer paper, there was almost no difference in density reduction, and abnormalities such as white spots and ghosts were observed. was not recognized at all.

Example 2 After forming an amorphous silicon layer on an aluminum support in the same manner as in Example 1, an amorphous carbon layer was formed using the ion blating apparatus shown in FIG.

The aluminum support on which the amorphous silicon layer was formed was fixed to a support jig of an ion blating device, and evacuated to high vacuum using an oil diffusion pump. Next, R material gas was introduced until a predetermined pressure was reached, and while rotating the aluminum support, high frequency ion blating was performed under the following conditions to form an amorphous carbon layer.

Amorphous carbon layer glue manufacturing method: High frequency ion blasting Raw material gas: C: 2HG Pressure crab 5 X 1O-3 Torr Substrate temperature = 50℃ High frequency output crab 100W High frequency frequency: 13.56M1lz DC voltage: 1500V Film thickness: 500 mm When the electrophotographic photoreceptor was evaluated in the same manner as in Example 1, almost no decrease in image density was observed, and no abnormal images were observed.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the structure of the electrophotographic photoreceptor of the present invention. FIGS. 2 and 3 are explanatory diagrams showing an example of an apparatus for mounting the electrophotographic photoreceptor of the present invention. 11... special holiday 13... photoconductive layer 15...
・Surface coating layer city 3 figure 1 s!

Claims (1)

[Claims] 1. An electrophotographic photoreceptor having a support, an amorphous silicon-based photoconductive layer provided on the support, and a surface protective film provided on the photoconductive layer, wherein the surface protective layer is made of carbon atoms. An electrophotographic photoreceptor comprising an amorphous layer containing as a main component.