JPS6067955A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide excellent stability and durability and to enable ultra-high speed copying by forming an a-Si.H.F.C surface protective layer by the glow discharge made with the gas volume of an F-contg. Si compd. at a specific content with respect to the gas volume of the F-contg. Si compd. and an H-contg. Si compd. CONSTITUTION:An a-Si barrier layer 4 is preferably formed on a conductive substrate 1 and an a-Si photoconductive layer 2 and an a-Si:H:F:C surface protective layer 3 are successively formed thereon. The surface protective layer 3 is formed by the glow discharge made in an atmosphere in which the gas volume of an F-contg. Si compd., for example, SiF4 is regulated to 20-50% with respect to the gas volume of the F-contg. Si compd. and an H-contg. Si compd., for example, SiH4. Gaseous H2 or rare gas, is incorporated as a carrier gas at 50-90% in the gas for decomposition by the glow discharge. A IIIa group element, for example, B or the like is incorporated into the surface protective layer. The stable operation characteristic and durability are further improved by providing the surface protective layer 3 on the photoconductive layer 2 in the above-mentioned way. The photosensitive body particularly adequate for ultra-high speed copying is obtd. Such photosensitive body is usable for an ultra-high speed copying machine, a laser beam printer etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvement of an electrophotographic photoreceptor using amorphous silicon (hereinafter referred to as a-Sj-) as a photoconductive layer.

In recent years, electrophotographic technology has made remarkable progress, and the development of ultra-high-speed copying machines and laser beam printers is actively underway.
However, the photoreceptors used in these devices are not used for long periods of time.
Since it is used at high speed, stability and durability of operation are required. Currently, electrophotographic photoreceptors include Se, C
Photoelectric materials such as dS and ZnO are commonly used, but a-8i is superior in heat resistance, abrasion resistance, non-pollution, photosensitivity, etc. Application to photoreceptors has been reported.

However, in today's situation where stable operation and outstanding durability are increasingly required, the A-81 photoreceptor reported up to now is no longer able to meet the demands (particularly in ultra-high speed copying). It cannot fully satisfy the characteristics required for a photoreceptor for use in other applications.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an electrophotographic photoreceptor suitable for ultrahigh-speed copying, which has extremely stable operating characteristics and extremely excellent durability.

The gist of the present invention is to provide a conductive substrate, preferably a-
A Si barrier layer is formed, and an a-Si photoconductive layer and an a-81 surface protective layer containing carbon as well as hydrogen and fluorine are sequentially laminated by a glow discharge decomposition method. In the body, the gas volume of the fluorine-containing silicon compound and the hydrogen-containing silicon compound is sealed, and a glow discharge is generated in an atmosphere in which the gas volume of the fluorine-containing silicon compound is 20 to 50%, and the a-S1 surface protection is performed. An object of the present invention is to provide an electrophotographic photoreceptor characterized by forming a layer.

The present invention will be explained in detail below.

As shown in FIG. 1(A), the electrophotographic photoreceptor of the present invention has an a-Si photoconductive layer (2) and an a-Si surface protection layer (3) sequentially laminated on a conductive substrate (II). Preferably, as shown in FIG. 1, a conductive substrate (1
) and the a-Si photoconductive layer (2), it is preferable to interpose an a-S'r barrier layer (4).

The a-Si photoconductive layer (2) contains at least one of hydrogen and fluorine, as well as oxygen and elements from periodic table No. 11 [a
containing boron, especially boron.

The a-Si surface protective layer (3) contains carbon as well as hydrogen and fluorine, and may further contain boron, a member of the Nta group of the periodic table.

In addition to at least one of hydrogen and fluorine, the a-81 barrier NJ T4+ contains, for example, at least one of oxygen, nitrogen, and carbon, as well as at least one of oxygen, nitrogen, and carbon, as well as at least one of hydrogen and fluorine. Contains Ma group, especially boron.

Table 1 shows the thickness and content of each layer when the a-S, i barrier layer (4) contains oxygen.

Table 1 Regarding Table 1, even when the a-Si barrier layer (4) contains nitrogen and carbon instead of oxygen.

The thickness of each layer as well as the content of other components are not changed at all. When each of nitrogen and carbon is contained independently in the a-Si barrier ff 141, the nitrogen content is 0.05 to 55 atoms, c%, and the carbon content is 0.05 to 45 atoms, c%. c%.

According to the present invention, the a-s1 surface-protected NI+31 can be treated with a starting material gas of boron (e.g., B2H6, etc.).
By adjusting the gas flow rate and specifying the content of each in the layer, as well as specifying the respective gas volumes of fluorine-containing silicon compounds such as Si and Fa, and hydrogen-containing silicon compounds such as Si and H4. It has been found that the photoreceptor has extremely stable operating characteristics and excellent durability.

That is, when the gas volume of the fluorine-containing silicon compound is less than 20% of the gas volume of the fluorine-containing silicon compound and the hydrogen-containing silicon compound, Si-F, which has a relatively large bonding energy, decreases and the durability deteriorates. If it exceeds 50% without contributing to improvement, dangling bonds of silicon atoms will increase, leading to a decrease in charge acceptance and deterioration of photosensitivity. Therefore, it is set in the range of 20 to 50%. It's good to do that. Fluorine-containing silicon compounds contain 5
There are various compounds such as i-Fa, SFa, and 51ate, and hydrogen-containing silicon compounds include Si, H4,5
isHa.

There are various compounds such as SiaHg. In the silicon compound gas, BgHa gas, etc., a rare gas such as Ar or He or H2 gas is used as a carrier gas, and according to the present invention, the surface protective layer (3) is formed by glow discharge decomposition method. It is preferable to set the amount in the range of 50 to 90% in the atmospheric gas to be formed.

Such conditions [thus formed a-81 surface protective layer (
3) can increase the carbon content to a minimum of 1 atomtc% and a maximum of 45 atomc% to 0%, thereby achieving the intended purpose of producing SIC and increasing the durability of the photoreceptor. can be achieved. Preferably, in order to further improve the charge retention ability, the carbon content is preferably set in the range of 1θ to 45 atoms 1c%.

And ゛, carbon is 1. At less than g atomtc %, no improvement in durability is observed, and the surface potential is low, resulting in no improvement in charge retention ability.

Further, when the thickness of the surface protective layer (3) is 0.01 #l or less, no improvement in durability is observed, and the surface potential is low, so that the charge retention ability is not improved. When the thickness is 0.5 μm or more, the photosensitivity tends to decrease and at the same time, the residual potential increases. Therefore, the layer thickness of the surface protective layer (31) is 0.01 to 0.5 μm.
, preferably in the range of 0.05 to 0.15 tin. In addition, the layer thickness of the first surface protective layer (3) should be adjusted according to the above-mentioned appropriate method, such that the larger the carbon content in the first surface protective layer (3), the smaller the layer thickness, and conversely, the smaller the carbon content, the larger the first layer thickness. determined within the range.

For the photoconductive layer (2), the oxygen content was 5 x 10
When the amount is -10-2 ato% or more, the photosensitivity decreases significantly.

On the other hand, if it is less than 10-'atomic%, the electrons of the dangling bond cannot be taken in sufficiently due to the large electronegativity of the oxygen atom, and therefore the a-Si has a dark resistance of more than 10 Ω・α. It is not possible to obtain a photoconductive layer, and the oxygen content of the photoconductive layer (2) is 10-5
To-gatomi, the range of 0% is good.

The barrier layer (4) smoothly transports carriers generated in the photoconductive layer (2) to the conductive substrate (1), and
) serves to prevent charge injection from On the other hand, in the absence of this barrier layer (4), the conductive substrate (1)
Injection of charge from the surface of the surface is not effectively prevented, the surface potential decreases, and the dark decay rate increases.

In order for the barrier layer (4) to work effectively, oxygen, nitrogen,
The carbon content is 0.05 to 60 atoms, respectively.
0%, Q, Q5~55 atoms (4%, 0.05~
45 atoms, c%; if at least one of these is Q, Q5 atoms, 0% or less, the injection of charge from the conductive substrate (1) is not sufficiently blocked, resulting in insufficient surface potential. When the dark decay rate increases and each independently exceeds the above maximum value, photocarriers are dragged and the residual potential increases. Note that this barrier layer may contain a combination of two or three of oxygen, nitrogen, and carbon, and the content of each is determined as appropriate depending on the combination.

In the a-, Si electrophotographic photoreceptor of the present invention.

When a carbon-containing a-81 surface protective layer is laminated on an a-Si photoconductive layer by glow discharge decomposition method, the gas volume of the fluorine-containing silicon compound and the hydrogen-containing silicon compound is Since the a-Si surface protective layer was formed by generating glow discharge in an atmosphere with a gas volume of 20 to 50%, the stable operating characteristics and durability achieved by incorporating carbon were further improved. In particular, it is suitable for photoreceptors for ultra-high speed copying.

Next, a capacitively coupled glow discharge decomposition apparatus for producing an a-Si layer will be described with reference to FIG.

1 in the diagram. Second. Third. 4th. 5th tank (5) f6
1 (71 (81 (91)) are SiF4.
Si, H4, B+I (a.

030E (4 gases are sealed. Also, SiF4
The carrier gas for both SiH+ and BIH6 gases is hydrogen. These gases correspond to the first. Second. Third
, 4th and 5th regulating valve (1 [1 former 1i1H131 (14
It is released by opening 1, and its flow rate is regulated by the mass flow controller 71 + 18, and the 1st, 2nd and 3rd tanks + 51 Fe2 (7
Gas from + goes to the 1st main pipe ■, and 4th and 5th tanks +81 (oxygen gas and methane gas from 91 go to the 2nd main pipe
It is sent to the main pipe t211. In addition, (211 is a stop valve. The gas flowing through the first and second main pipes is the reaction pipe Q4.
A capacitively coupled discharge electrode (to) is arranged around the base inside this reaction tube, and its high frequency power is 50 watts to 3 kj-1 ow.
atts and the frequency is 1. MHz to number IQ M
Hz is appropriate. Inside the reaction tube C4, there is a-
8ill19B is formed. For example, a substrate (a) such as aluminum or NESA glass is placed on a turntable (Oa) which can be rotated by a motor (5), and the substrate (c) itself is heated by a suitable heating means for approximately 50 minutes.
It is uniformly heated to a temperature of 0 to 300°C, preferably about 150 to 250°C. Also, the inside of the reaction tube (goods) is a
-Si, which requires a high vacuum state (discharge voltage 0.5 to 2.0 Torr) during film formation, is connected to the rotary pump (2) and the diffusion pump (1).

In the glow discharge decomposition apparatus having the above configuration, for example, when forming a carbon-containing a-Sj- film on the substrate (a), the fifth regulating valve ( 141 and open the 1st and 2nd tanks (5
1 (from 61, SiF + gas, S, 1-H4 gas,
When introducing methane gas from the tank (9) and also containing boron, open the third adjustment valve 2 and move the tank (7) to the third tank (7).
BsH6 gas is released. The amount of emissions is regulated by the mass flow controller Mi9e (171 (19),
The flow rate of SiF+ gas and/or S'LH+ gas is specified, and the gas mixed with B2H6 gas is supplied to the first main pipe ■
via and with Si, F4 and/or ji
Methane gas in a constant molar ratio to 5iE (4i) is sent to the reaction tube via the second main pipe CD.

And the inside of the reaction chamber (2) is 0.5 to 2.0, T
True wall state of about Qrr, substrate temperature 50 to 300℃,
The high frequency power of the capacitive discharge electrode (c) is 50 watts
s to 3 ki, lowatts, and the frequency is set from 1 to several 10 MHz), a glow discharge occurs, the gas is decomposed, and fluorine, hydrogen, and a-Si film containing carbon, or
In addition, an a-Si film containing an appropriate amount of boron is formed at a deposition rate of about 10 to 2500 A/min.

Examples of the present invention will be described below.

[Example 1] An a-81 photoconductive layer, a-Si, and a surface protective layer were formed using the glow discharge decomposition apparatus shown in FIG. 2 described above, and the durability of this photoreceptor was tested.

That is, the turntable (2) of the glow discharge decomposition device
A cylindrical aluminum substrate (1) is placed on top of the Si, F4 substrate with hydrogen as a carrier gas from the first tank (5).
Gas (flow rate tao sccM) is transferred to the second tank (6)
Si, H+ gas (flow rate 190 SOQM) with hydrogen as the carrier gas from the third tank (7), and B1 with hydrogen as the carrier gas from the third tank (7)! Ha gas (flow rate 89 se
cM), and the fourth tank (81j) releases oxygen gas (flow ii''c1,4 secM), and the gas composition of the glow discharge atmosphere is determined according to the ratio of these gas flow rates. , about 1O-10-8ato% of oxygen and about 200p of boron on the aluminum substrate (1).
pm, hydrogen and 77 elements total about 15 atoms
, c% of a-Sj-photoconductive layer having a thickness of lQttm was obtained. The manufacturing conditions at this time were to set the discharge voltage to 0.6 Torr.
, substrate temperature 200℃, high frequency power 200W
atts, and the film formation rate was set to 14 A/sθC. Furthermore, in the same manner, Si, F+ gas was heated to 20 SOC.
M.

SiH4 gas at 30 sccM, BsHa gas at 1
An a-81 surface protective layer was formed on the a-Si photoconductive layer under the same conditions except that methane gas was further discharged from the fifth tank (9) at a flow rate of 25 secM and 20 secM.

At this time, in a glow discharge atmosphere, SiF4 and Si
Si, F4 gas volume relative to H4 gas volume is approximately 40
The amount of H2 gas used as a carrier gas was approximately 80%. This reduces carbon to about 20 atoms.
tc%, approximately 200 ppm boron, and a total of approximately 5 atomic% fluorine and hydrogen, 0.1 μm thick.
a-8i, a surface protective layer was obtained.

It has been confirmed that this electrophotographic photoreceptor has excellent photosensitivity characteristics including in the long wavelength region, and furthermore, it has been confirmed that the electrophotographic photoreceptor has excellent photosensitivity characteristics including the long wavelength region, and furthermore,
When charged with a 6 k'V corona charger and followed the change in surface potential over time in the dark and the change in surface potential over time immediately after irradiation with monochromatic light of 77On1ll, the surface potential was 70
It was found that it has significantly higher voltage than 0V, slow dark decay, and excellent charge retention ability.As a result, it was found that it can be used in a wide range of future applications, such as application to laser beam printers using semiconductor lasers. .

Regarding the electrophotographic photoreceptor thus obtained, 5.6 kV
After being charged with a corona charger, image exposure was performed and a magnetic brush phenomenon was performed.As a result, a good image with high image density and high contrast was obtained.Even after 400,000 repeated tests, there was no decrease in density or white background. There was no visible deterioration from the initial image, such as fogging or white spots due to scratches on the drum surface.

It was confirmed that the durability was also good.

[Example 2] In the photoreceptor obtained in Example 1, a barrier layer (4) formed under the following manufacturing conditions was interposed between the aluminum substrate (1) and the photoconductive layer (2). I made a photographic photoreceptor.

That is, SiF4 gas was heated in a glow discharge decomposition apparatus shown in FIG. OSof3M%SiH+gas at 30 sccM
, Bl! The tcp element on the aluminum substrate (1) was approximately 0.6 scc under the conditions of Example 10, except that the He gas was used at a flow rate of 125 sccM and the CH4 gas was used at a flow rate of 0.8 SOQM.
A 2 μm thick a-85-barrier layer was obtained containing about 200 ppm boron and about 5 atomic 0% fluorine and hydrogen in total. Then, on top of this, an a-Si photoconductive layer exactly the same as in Example 1 and an a-Si photoconductive layer were formed.
An electrophotographic photoreceptor was obtained by sequentially laminating Si-surface protective layers.

Regarding the electrophotographic photoreceptor thus obtained, 5.6 kV
After being charged with a no-corona charger.

As a result of image exposure and magnetic brush phenomenon, a good image with high image density and high contrast was obtained, and even after 400,000 repeated tests, there was no loss of density, fogging of the white background, or white spots due to scratches on the drum surface. No deterioration was observed at all from the initial image, and it was confirmed that the durability was good.

Furthermore, the electrophotographic photoreceptor obtained in this example has excellent photosensitivity characteristics, including in the long wavelength region.
．． According to the change in surface potential over time in the dark after charging with a 6 kV corona charger and the change in surface potential over time immediately after irradiation with monochromatic light of 170 nwr, the surface potential was much higher by C than in Example 1. , 850V or more, and it was found that the charge retention ability was also suitable.

[Example 3] When forming the surface protective layer described in Example 1, SiF'+ gas with hydrogen as a carrier gas was supplied from the first tank (5), and hydrogen was used as a carrier gas from the second tank (6). Photoreceptors (Al tBl (C1 and CD)) were manufactured by changing the release amount of each of the 5l-H4 gases and changing the gas composition of the glow discharge atmosphere as shown in Table 2. The manufacturing conditions were exactly the same as in Example 1.

The durability of the photoreceptor was confirmed by the method described in Example 1, and the results are shown in Table 2. Note that the evaluation of the durability test in Table 2 was based on the limit number of repetitions at which deterioration from the initial image was observed.

As is clear from Table 2, the photoreceptor IB) tc) is
■Concentration does not decrease even after repeated testing 10,000 times.

There is no deterioration from the initial image, such as fogging on the white background or white spots due to scratches on the drum surface, and the durability has been significantly improved, making it fully satisfactory as a photoreceptor for ultra-high speed copying. It turns out. However, the photoreceptor (Al (
With Dl, the number of cycles was 200,000 to 150,000 cycles at most, which was approximately the same level as the conventional a-Si photoreceptor.

As is clear from the examples described above, a-S of the present invention
1. A photoreceptor has a surface protective layer laminated on a photoconductive layer, and when forming the surface protective layer using a glow discharge decomposition device, the gas composition of the fluorine-containing silicon compound and the hydrogen-containing silicon compound must be specified. As a result, extremely stable operating characteristics and excellent durability have been obtained, and as a result, it is expected to be used as a photoreceptor for ultra-high speed copying, which will be increasingly required in the future.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of a photoreceptor according to the present invention, and FIG. 2 is a schematic diagram showing a glow discharge decomposition apparatus for forming an amorphous silicon layer. +11-...Conductive substrate (2)...Amorphous silicon photoconductive [Ml(31-
・Amorphous silicon surface protective layer (41...Amorphous silicone 1lIiJl Patent applicant: Kyocera Corporation Takao Kawamura

Claims (1)

[Claims] An amorphous silicon photoconductive layer and an amorphous silicon surface protective layer containing carbon as well as hydrogen and fluorine are deposited on an il+ conductive substrate by a glow discharge decomposition method.
In an electrophotographic photoreceptor 1 formed by sequentially laminating layers, the gas volume of the fluorine-containing silicon compound is 20% of the gas volume of the fluorine-containing silicon compound and the hydrogen-containing silicon compound.
An electrophotographic photoreceptor, characterized in that the amorphous silicon surface protective layer is formed by generating glow discharge in an atmosphere of 50% to 50%. (21iJ) An electrophotographic photosensitive material consisting of an amorphous silicon barrier layer, an amorphous silicon photoconductive layer, and an amorphous silicon surface protective layer containing carbon as well as hydrogen and fluorine, successively laminated on a transparent substrate by glow discharge decomposition method. In the body, a glow discharge is generated in an atmosphere in which the gas volume of the fluorine-containing silicon compound is 20 to 50% of the gas volume of the fluorine-containing silicon compound and the hydrogen-containing silicon compound, and the amorphous silicon surface protective layer is (3) Along with the glow discharge decomposition gas, at least one of hydrogen gas and rare gas as a carrier gas occupies the atmosphere gas of the glow discharge, and the proportion thereof is 50 to 90%. (4) The electrophotographic photoreceptor according to claim 1 or 2, characterized in that the fluorine-containing 7a recon compound is SiF+. or the electrophotographic photoreceptor according to claim 2. (5) The electrophotographic photoreceptor according to claim 1 or 2, characterized in that the hydrogen-containing silicon compound is SiH+. 3. The electrophotographic photoreceptor according to claim 1 or 2, wherein the silicon surface protective layer contains a member of group Ma of the periodic table.