JPS6228764A - Photosensitive body - Google Patents

Abstract

PURPOSE:To improve the mechanical and the optical properties and the stability of the titled body by laminating the prescribed layers composed of such as a specific amorphous hydrogenated silicon (a-Si:H) etc. respectively. CONSTITUTION:An electric charge blocking layer 44 composed of a-Si:H contg. at least one kind atom selected from a carbon, a nitrogen and an oxygen atoms and an photoconductive layer 43 composed of a-Si:H, the intermediate layer 46 composed of a-Si:H contg. at least one kind atom selected from the carbon and the nitrogen and the oxygen atoms and dopped with the group IIIa or Va element of the periodic table and the surface reforming layer 45 composed of a-Si:H contg. large amounts of the atom are laminated on the layer 41 to form the photosensitive body 39. By providing the layers 45-46, the mechanical strength of the titled body becomes large. The adhesive property, the anti-fatigue property against a light and the anti-chemical stability of the layers 45 and 43 are improved. The effects as prescribed above are obtd. by merely using a fluorinated silicon or by jointly using the fluorinated silicon and the prescribed silicon.

Description

[Detailed description of the invention]

B. Industrial Application Field The present invention relates to a photoreceptor, for example, an electrophotographic photoreceptor. Conventional technology Conventionally, as an electrophotographic photoreceptor, Se or Se has As, T
Photoreceptors doped with e.g., Sb, etc., and photoreceptors in which ZnO or CdS is dispersed in a resin binder are known. However, these photoreceptors have problems in environmental pollution, thermal stability, and mechanical strength. On the other hand, electrophotographic photoreceptors using amorphous silicon (a-8i) as a matrix have been proposed in recent years. a-8i has a so-called dangling bond in which the bond of 5i-8i is broken, and many localized levels exist within the energy gap due to this defect. Under this condition, hopping conduction of thermally excited carriers occurs, resulting in a small dark resistance, and photoexcited carriers are trapped in localized levels, resulting in poor photoconductivity. Therefore, the above defects are replaced with hydrogen (H
), the dangling bonds are filled by bonding H to Sl with compensation. Such amorphous hydrogenated silicon (hereinafter referred to as a-8
It is called i:H. ) has a resistivity in the dark of 108 to 10
gΩ-σ, which is about 1 compared to amorphous Se.
It's even lower than 1/10,000. Therefore, a photoreceptor made of a single layer of a-8i:H has problems in that the dark decay rate of the surface potential is high and the initial charging potential is low. However, on the other hand, when irradiated with light in the visible and infrared regions, the resistivity is greatly reduced, so it has extremely excellent properties as a photosensitive layer of a photoreceptor. Figure 8 shows a-8i with the above a-si:) (as the base material).
An electrophotographic copying machine incorporating a system photoreceptor 9 is shown. According to this copying machine, a glass document mounting table 3 on which a document 2 is placed and a platen cover 4 that covers the document 2 are disposed in the upper part of a cabinet 1. Below the document table 3,
An optical scanning table consisting of a first mirror unit 7 equipped with a light source 5 and a first reflecting mirror 6 is provided so as to be movable linearly in the left-right direction of the drawing, and the optical path length between the document scanning point and the photoreceptor is kept constant. The second mirror unit (20) moves according to the speed of the first mirror unit, and the reflected light from the document table 3 passes through the lens 21 and the reflection mirror 8 onto the photosensitive drum 9 as an image carrier. The light enters in a slit shape. Around the drum 9, a corona charger 10,
A developing device 11, a transfer section 12, a separation section 13, and a cleaning section 14 are arranged, and the copy paper 18 fed from the paper feed box 15 via each paper feed roller 16, 17 is further processed after the toner image on the drum 9 is transferred. The image is fixed by the fixing unit 19, and the paper is ejected to the lower tray. In the fixing section 19, the developed copy paper is passed between a heating roller B having a built-in heater n and a pressure roller U to perform a fixing operation. However, photoreceptors with a-8i:H surfaces are susceptible to surface chemical stability, such as the effects of long-term exposure to the atmosphere or moisture, and the effects of chemical species generated by corona discharge. , has not been sufficiently investigated so far. For example, if a friend is left alone for more than a month, it will be affected by humidity.
It is known that the receptor potential is significantly reduced. On the other hand, amorphous hydrogenated silicon carbide (hereinafter a-8iC:H
It is called. ), its manufacturing method and existence are @Ph1l. Mag, vol. 35'' (1978), etc., and its characteristics include high heat resistance and surface hardness, and a high dark resistivity (t) compared to a-8i:H.
It is known that the optical energy gap changes over a range of 1.6 to 2.8 ev depending on the amount of carbon. However, there is a drawback that the long wavelength sensitivity becomes poor due to the widening of the band gap due to the inclusion of carbon. An electrophotographic photoreceptor combining these p a -5ic: H and a -8i: H is disclosed in, for example, JP-A-55-127.
This is proposed in Publication No. 083. According to this,
The a-8i:H layer is a charge generation (photoconductive) layer, and the a-8iC:l (layer is provided below this charge generation layer, and the upper layer a-8
i:H provides photosensitivity in a wide wavelength range, and a-8i
The charging potential is improved by the lower layer a-8iC:H forming a heterojunction with the :H layer. However, a
The dark decay of the -8i:H layer cannot be sufficiently prevented, the charging potential is still insufficient and it is not practical, and the presence of the a-8i:H layer on the surface Chemical stability, mechanical strength, heat resistance, etc. become poor. On the other hand, JP-A-57-17952 discloses a-8i:
A first a-8iC:H layer is formed as a surface modification layer on the charge generation layer made of H, and a second a-8iC:H layer is formed on the back surface (support electrode side).
A-8iCSH layer is formed. In addition, as related to this known technology,
As disclosed in Japanese Patent No.-23543, a graded layer (a-811-Cx:H) is provided between the charge generation layer and the first and second a-8iC:H layers, and in this graded layer, A photoreceptor is known in which X=O on the a-si:) (side) and X = 0.5 on the a-8iC:H layer side. However, the inventors have investigated the above-mentioned known photoreceptor. As a result, it was found that the effect of providing the surface modification layer was not so pronounced, especially in continuous repeated use.That is, during continuous running of 10,000 times, the surface a-8iC layer was 7 to 8 It is mechanically damaged after 10,000 times, resulting in white streaks and white spots as image defects, so printing durability is not sufficient.Furthermore, light resistance fatigue occurs during repeated use, and image fading occurs. Electrical
The optical properties are not always stable, and the influence of the usage environment (temperature, humidity) cannot be ignored. Furthermore, it is necessary to further improve the adhesion between the surface modified layer and the charge generation layer. C1 Object of the invention The object of the invention is to provide excellent adhesion between the surface modification layer and the charge generation layer, resistance to mechanical damage, and excellent printing durability.
Stable image quality without image blurring is obtained, there is little optical fatigue during repeated use, the residual potential is low, and the characteristics are compatible with the usage environment (
The purpose of the present invention is to provide a photoreceptor that is stable regardless of temperature and humidity. 20 Structure and effects of the invention, that is, the present invention provides a charge blocking layer made of amorphous hydrogenated and/or fluorinated silicon containing at least one of carbon atoms, nitrogen atoms, and oxygen atoms; and/or a photoconductive layer consisting of fluorinated silicon; an amorphous hydrogenated layer doped with an element of group IIIa or group Va of the periodic table and containing at least one of carbon atoms, nitrogen atoms and oxygen atoms; or an intermediate layer made of fluorinated silicon; and a surface modified layer made of amorphous hydrogenated and/or fluorinated silicon containing more at least one of carbon atoms, nitrogen atoms, and oxygen atoms than the intermediate layer; This relates to a photoreceptor formed by sequentially laminating layers. According to the present invention, since the surface modified layer contains at least one atom of carbon, nitrogen, and oxygen, it is resistant to mechanical damage, and there is no deterioration in image quality due to white streaks, etc., and it is resistant to Excellent printability. Further, in the present invention, since the impurity-doped intermediate layer is provided between the surface modified layer and the photoconductive layer, the adhesion between the surface modified layer and the photoconductive layer is improved. In addition, since the surface-modified layer and intermediate layer are provided on the photoconductive layer, in addition to the above, it has excellent light fatigue resistance during repeated use, has no image loss, has low residual potential, and has low electrical potential. It has been confirmed that the optical and optical properties are always stable and unaffected by the usage environment. E. Examples Hereinafter, the present invention will be explained in detail with reference to examples. FIG. 1 shows an a-8i electrophotographic photoreceptor 39 for positive charging according to this embodiment. This photoreceptor 39 is
'Va of the periodic table on a drum-shaped conductive support substrate 41 such as
Group elements (e.g. phosphorus) are heavy dogged and C,N
and a-8i:H (this is expressed as a-8i (C) (N) (0) :H)), and a-8i:
A photoconductive layer 43 consisting of H (without impurity doping or made intrinsic) and a heavy doping of an element of Group 1 Ja or Group Va of the periodic table, and is P+ type or N+ type, and at least one of C, N, and 0. an intermediate layer 46 made of amorphous hydrogenated silicon containing
Amorphous hydrogenated silica doped with group IA or group Va elements to make it Pfi or N type or intrinsic (or without impurity doping) and containing at least one of N, C and O: +7 (a-8i ( C) (N)
It has a structure in which a surface modified layer 45 consisting of (0) :H) is laminated. The charge generation layer 43 has a dark resistivity ρ. The ratio of resistivity ρ when irradiated with light is sufficiently large as an electrophotographic photoreceptor, and the photosensitivity (particularly to light in the visible and infrared regions) is good. In addition, when the carbon atom content of each of the above layers is in the range of 0 to 70%, the optical energy gap (
Since there is a substantially linear relationship with Egt opt ), the carbon atom content can be defined by replacing it with the optical energy gap. Furthermore, if the carbon atom content of a-8iC:H is appropriately selected, remarkable effects such as an increase in specific resistance and an improvement in the charging potential holding ability can be obtained as shown by curve a in FIG. 3. That is, as shown by curve a in FIG. 3, the carbon atom content is 3f.
)-90 Ω a-8iC:H is used for fC, its resistivity changes according to the carbon content and becomes 10 12 Ω-α or more. The above tendency is that a-8iN containing N or 0 instead of carbon
The same applies to :H, a-8iO:H. The above layer 45 is indispensable for modifying the surface of the photoreceptor and making the a-8i photoreceptor practically excellent. That is, it enables the basic operations of an electrophotographic photoreceptor, such as charge retention on the surface and attenuation of the surface potential due to light irradiation. Therefore, the repetitive characteristics of charging and optical attenuation become very stable, and good potential characteristics can be reproduced even if left for a long period of time (for example, one month or more). On the other hand, in the case of a photoreceptor having a-8i:H as its surface, it is easily affected by humidity, air, ozone atmosphere, etc., and the potential characteristics change significantly over time. Furthermore, since the layer 45 has a high surface hardness, it is resistant to abrasion during processes such as development, transfer, and cleaning, and it also has good heat resistance, so a process that applies heat such as adhesive transfer can be applied. can. In order to achieve the above excellent effects comprehensively, layer 4 is required.
It is important to select a composition of 5. That is, when containing carbon atoms, S i + C= 100 atoms
When ic chi (hereinafter, atomic% is simply expressed as chi), 1 chi≦(C)≦90chi, furthermore, 10%≦[C]
It is desirable that it be ≦70chi. With this C content, the above-mentioned specific resistance becomes the desired value, and the optical energy gap becomes approximately 2.5 eV or more, and the irradiated light is a -si:I (It becomes easier to reach the OK layer. However, if the C content is less than 1%, defects such as mechanical damage occur, and the specific resistance tends to fall below the desired value, and part of the light is transmitted to the surface layer. 45, and the photosensitivity of the photoreceptor tends to decrease.In addition, if the C content exceeds 90%, the amount of carbon in the layer becomes large9, the semiconductor properties are easily lost, and the 3-sic:n film When forming by glow discharge method, the deposition rate tends to decrease, so the C content is preferably 90 or less.Similarly, in the case of the layer 45 containing nitrogen or oxygen, 1 chi≦(N) ≦90
Chi (furthermore, 10 chi≦(N)≦70 chi) is good, and 0%<(
0)≦70chi (even 5chi≦)

[0]≦30) Good. In order to improve the charging ability, the surface modified layer 45 may have a high resistance. For this purpose, the surface modified layer may be made intrinsic. In order to facilitate the injection of electrons or holes from the intermediate layer into the surface-modified layer and to minimize the residual potential when used with positive or negative charging, the surface-modified layer may be of P or N type. The amount of impurity doped in each case (at the time of glow discharge decomposition described later) may be as follows. N type: PH8/5iI(,1~1000 〃(a-8
iCO:H(F), a-8iNO:H(F″) common) Also, the layer 45 is a-3iC01a-8iNO, a-8i
n. a-8iO, etc., and the film thickness is 400
Within the range of X≦t≦5000 years (especially 400X≦t
It is also important to select 00X. That is, if the film thickness exceeds 500 OA, the residual potential v1 becomes too high and the photosensitivity decreases, making it easy to lose good characteristics as an a-8i photoreceptor. In addition, if the film thickness is less than 400 mm, the tunnel effect prevents charges from being charged on the surface, resulting in an increase in dark decay and a decrease in photosensitivity. It is installed to improve the image quality, reduce the residual potential, improve the adhesion of the surface-modified layer, and stabilize the image. In order to improve the above characteristics, it is necessary to make it P or N type. The amount of impurity doping is (:PH5)/(Si)14) = 1~1000 (
Preferably 50-500) capacity ppm. (BtH6) / (SIH+) = 1~1ooo (
Preferably, the capacity may be 50 to 500 ppm. The content of C, N, and 0 in the intermediate layer 46 is preferably 0<(C)510%, 0<[:N)≦10%, and 0<(0)≦5%. The thickness of this intermediate layer is preferably 50 to 5000 A, but if it exceeds 5000 K, the same phenomenon as described above tends to occur, and if it is less than 50X, the effect as an intermediate layer becomes poor. Regarding the photoconductive layer, in order to improve the charging ability,
The charge generation layer may be made to have a high resistance, and for this purpose, the charge generation layer may be made intrinsic. For this, B, H
,/SiH,=O~50 ppm by volume. The amount is preferably 1 to 20 ppm by volume. The thickness of the photoconductive layer is preferably 5 to 80 μm, preferably 10 to 10 μm. If the thickness of the photoconductive layer is less than 5 μm, a sufficient charging potential cannot be obtained, and if it exceeds 80 μm, the residual potential increases, which is insufficient for practical use. In addition, the charge blocking layer 44 sufficiently prevents electron injection from the substrate 41, and in order to improve sensitivity and charging ability, a group VA element (for example, phosphorus) of the periodic table is doped by glow discharge decomposition. Then, it becomes N type (and even N+ type). The doping amount is controlled by the composition of the blocking layer as follows. a-8iC: Intrinsic B, H, /8iH, 2-20 capacity p
pmN type (N”) PH8/8i)I, 1-1000
//a-8iN: Intrinsic B, H, /5iH41-2
000 ttN type (N +) PH, /5iH41~
2000 volume-i ppm blocking layer is 5iO1Si
Compounds such as n, etc. may also be used. The thickness of the blocking layer 44 is preferably 5001 to 2 μm. If it is less than 500 A, the blocking effect is weak;
Further, if the thickness exceeds 2 μm, the charge transport ability tends to deteriorate. The composition of the blocking layer 44 is preferably as follows. That is, 1%<(C)≦90chi, preferably 10chi≦[C]≦70t4, 1%〈[N]≦90chi, preferably 10chi〈[N]≦70chi, and 0%≦ [0
]≦70%, preferably Ochi≦

It is preferable that [0]≦30%. Note that each of the above layers needs to contain hydrogen. In particular, the hydrogen content in the core of the charge generation layer is essential for compensating for dangling bonds and improving photoconductivity and charge retention, and is preferably from 10 to 30%. This content range is the same for the surface modification layer 45 and blocking layer material. Mayu, as an impurity for controlling the conductivity type of the blocking layer material, in addition to boron, kl, Ga,
Group IIIa elements of the periodic table, such as In and T1, can be used. For N-type conversion, in addition to phosphorus, group Va groups of the periodic table, such as As and sb, can also be used. Next, a method for manufacturing the above-mentioned photoreceptor (for example, drum-shaped) and an apparatus therefor (glow discharge apparatus) will be explained with reference to FIG. A drum-shaped substrate 41 is vertically and rotatably set in a vacuum chamber 52 of this device 51, and a heater I can heat the substrate 41 from the inside to a predetermined temperature. A cylindrical high-frequency electrode 57 with a gas outlet 53 is disposed around and facing the substrate 41, and a glow discharge is generated between the high-frequency power source and the substrate 41. In addition, 62 in the figure is a source of SiH or a gaseous silicon compound, 6
3 is a supply source of hydrocarbon gas such as CH, the figure is a supply source of nitrogen compound gas such as N2, field is a supply source of oxygen compound gas such as 02, mark is a carrier gas supply source such as A, r, etc., 67 is an impurity gas (for example, (By)le) supply source, and each line is a flow meter. In this glow discharge device, first, the surface of a support, for example, an AI substrate 41, is cleaned and then placed in a vacuum chamber 52, and the gas pressure in the vacuum chamber 52 is set to 10-'To.
The substrate 41 is heated to a predetermined temperature, particularly 100 to 350°C (preferably 150 to 30°C).
Heat and maintain at 0℃). Next, using a high-purity inert gas as a carrier gas, SiH, gaseous silicon compound, CH4, N2.02, etc. are appropriately introduced into the vacuum chamber 52, and a high frequency power source is applied under a reaction pressure of, for example, 0.01 to 10 Torr. A higher frequency voltage (e.g. 1.3.56 MHz
) is applied. As a result, each of the above reaction gases is decomposed by glow discharge between the electrode 57 and the substrate 41, and the N+ type a-
sico: H, a-8i: H, P+ or N+ type a-si
co:H, a-8icO:H in the above layer 44.43.4
6.45 on the substrate successively (i.e. corresponding to the example of FIG. 1, for example). In the above manufacturing method, the support temperature is set at 100 to 350°C in the step of forming the a-8i layer on the support, so the film quality (especially electrical properties) of the photoreceptor can be improved. . In addition, when forming each layer of the above a-8i photoreceptor,
In order to compensate for dangling bonds, fluorine is introduced in the form of SiF4, etc., in place of the above-mentioned H or in combination with H, and a-8i:F, a-8i:H:F, a
-8iN:F, a-8iN:H:F. It can also be a-sic:F', a-8iC:H:F. In this case, the amount of fluorine is preferably 0.5-10. Note that the above manufacturing method is based on the glow discharge decomposition method, but other methods include sputtering method, ion blating method, and method of evaporating Si while introducing hydrogen that has been cleaned or ionized with a hydrogen discharge tube. , (particularly in Japanese Patent Application Laid-open No. 1524-1983, filed by the present applicant)
The above photoreceptor can also be manufactured by the method of No. 55). Hereinafter, the present invention will be described with reference to specific examples. By glow discharge decomposition method, drum-shaped A! first on the support
An electrophotographic photoreceptor having the structure shown in the figure was manufactured. First, the surface of a support, for example, a drum-shaped Al substrate 41 having a smooth surface, is cleaned and then placed in a vacuum chamber 52 shown in FIG.
The substrate 41 is heated to a predetermined temperature, particularly 100 to 350°C (preferably 150 to 350°C).
00°C). Next, high-purity Ar gas was introduced as a carrier gas, and high-frequency power with a frequency of 13.56 MHz was applied under a back pressure of 0.5 Torr to perform a preliminary discharge for 10 minutes. Next, a reaction gas consisting of SiH and PH8 was introduced at a flow rate ratio of 1:1.
: 1 : (1,5 cut o ”-3>(Ar+SiH
, +CH, +PH,) by glow discharge decomposition of the mixed gas, N+tDa which plays a charge blocking function.
-8i CO:H layer 44 was formed to a predetermined thickness at a deposition rate of 6 μm/hr. Subsequently, the supply of PHs and CH4 was stopped, SiH was decomposed by discharge, and a 5 pm thick a
-8i: HIiI43 was formed. Subsequently, glow discharge decomposition is performed by changing the flow rate ratio of impurity gas to form an intermediate layer 46 whose film thickness is also changed, and further a-8iCO:H
Alternatively, an a-8iNO:H surface protective layer 45 was further provided to complete the electrophotographic photoreceptor. As a comparative example, a photoreceptor without an intermediate layer was prepared. The structure of the photoreceptor thus created is summarized as follows. (1) 0 surface modification layer: a-8iNO:H or a-8iC
O:H (2), intermediate layer: doping amount, film thickness change (see Figure 5) (3), a-8i:H photoconductive layer: film thickness =
19 μm (4), a-8iCO:H or a-8iN
O:H charge blocking layer: film thickness = 0.5 ttm carbon content = 11 inches (5), support: Al! cylinder(
(Mirror Polished Finish) Next, various tests were conducted using each of the above photoreceptors as follows. A load W is applied to the 0 and 3R diamond needles 70, and the photoreceptor is rotated by the motor 71 to scratch it. Next, an image is produced using a modified electrophotographic copying machine U-Bix 1600 (Konishiroku Photo Industry Co., Ltd.), and the scratch strength (g ). Under an environment with an image flow temperature of 33'C and a relative humidity of 80%, the photoreceptor was placed in a modified electrophotographic copying machine U-Bix 4500 (Konishi Roku Photo Industry Co., Ltd.) for M hours.
After idling 1000 copies without contacting the blade, image production is performed. The degree of image blurring was determined using the following criteria. ◎There is no image blurring at all, and the reproducibility of 5.5-point alphabetic characters and thin lines is good. Q: The 5.5 point letters are slightly thicker. △: 5.5 point letters are crushed and difficult to read. X: S, S point letters are illegible. Residual potential V, (V) Potential measurement using a modified U-Bix2500 machine, 400
Static neutralizing light with a peak at nm 30 l u x * se
The surface potential of the photoreceptor that remains after irradiation with e. Charging potential V0 (V) Surface potential just before development measured with a 360 SX type electrometer (manufactured by Trek) using a modified U-Bix 2500 machine (manufactured by Konishiroku Photo Industry Co., Ltd.) and under the condition that the photoconductor inflow current was 200 μA1 and no exposure. . Half-decreased exposure amount F' Vz (1ux-sec) Using the above-mentioned device, the long wavelength component of 620 nm or more of the volatile exposure wavelength produced by the Gikroic mirror (manufactured by Koshin Kogaku Co., Ltd.) is sharply cut, and the surface potential is The amount of exposure required to halve from 500V to 250V. (The exposure amount was measured using a 550-IM light meter (EG and G
(manufactured by). ) The results are summarized in Figure 7. These results show that if a photoreceptor is prepared according to the present invention, a photoreceptor with excellent performance for electrophotography can be obtained.

[Brief explanation of drawings]

1 to 7 show examples of the present invention.
A graph showing the optical energy gap of iC, Fig. 3 a graph showing the specific resistance of a-8iC, Fig. 4 a schematic cross-sectional view of the glow discharge device, Fig. 5 a table showing the layer structure of each photoreceptor, FIG. 6 is a schematic diagram of a scratch strength tester, and FIG. 7 is a table showing the characteristics of each photoreceptor. FIG. 8 is a schematic sectional view of a conventional electrophotographic copying machine. In addition, in the reference numerals shown in the drawings, 39...A-8i system bad sensitivity 41...Support (substrate) 42...Charge transport layer...Charge generation layer polarization... . . . Charge blocking layer 45 . . . Surface modification layer 46 . . . Intermediate layer.

Claims (1)

[Claims] 1. A charge blocking layer made of amorphous hydrogenated and/or fluorinated silicon containing at least one of carbon atoms, nitrogen atoms, and oxygen atoms; and a photoconductive layer made of amorphous hydrogenated and/or fluorinated silicon. and; an intermediate layer made of amorphous hydrogenated and/or fluorinated silicon doped with an element of Group IIIa or Group Va of the periodic table and containing at least one of carbon atoms, nitrogen atoms, and oxygen atoms; and; carbon atoms. and a surface-modified layer made of amorphous hydrogenated and/or fluorinated silicon containing at least one of nitrogen atoms and oxygen atoms in a larger amount than the intermediate layer.