JPS6283764A - Photosensitive body - Google Patents

Abstract

PURPOSE:To make it possible to raise a mechanical strength, and to give a high durability of the titled body by providing an intermediate layer which is composed of an amorphous hydrogenated and/or halogenated silicon contg. an oxygen atom, and contains less the oxygen atom than that of the electric charge transfer layer between the charge transfer layer and the electric charge generating layer. CONSTITUTION:The titled body comprises the charge transfer layer 42 which is composed of the amorphous hydrogenated and/or halogenated silicon contg. the oxygen atom and is doped with an element belonging to the group IIIa of the periodic table of the element and the charge generating layer 43 which is composed of the amorphous hydrogenated and/or halogenated silicon, and is provided on the charge transfer layer, and the intermediate layer 47 which is composed of the amorphous hydrogenated and/or halogenated silicon contg. the oxygen and contains less the oxygen atom than that of the charge transfer layer and is provided between the charge transfer layer and is provided between the charge transfer layer 42 and the charge generating layer 43. Thus, the titled body having a high performance against a mechanical strength and the fade of the image and a high sensitivity and a high durability and a high image quality is obtd.

Description

[Detailed description of the invention]

B. Industrial Application Field The present invention relates to a photoreceptor, for example, an electrophotographic photoreceptor. 3. Background of the Invention Conventionally, electrophotographic photoreceptors have been made of Se, or Se plus As,
Photoreceptor doped with Te, Sb, etc., ZnO or CdS
Photoreceptors, etc., in which the compound is dispersed in a resin binder are known. However, these photoreceptors have problems in terms of environmental pollution, thermal stability, and mechanical strength. On the other hand, electrophotographic photoreceptors using amorphous silicon (hereinafter referred to as a-Si) as a matrix have been proposed in recent years. The a-8i has a so-called dangling bond with the 5i-8t supply chain broken.
Many localized levels exist within the energy gap due to this defect. For this reason, 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, by compensating the above defects with hydrogen atoms (1()), H
Dangling bonds are filled in by making these bonds. Such amorphous hydrogenated silicon (hereinafter referred to as a-8
It is called t:H. ) has a resistivity in the dark of 10"~101
Ω-cm, 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-8t:H has problems in that the dark decay rate of the surface potential is slow 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. In addition, photoreceptors with a-8t:H surfaces are susceptible to surface chemical stability, such as the effects of long-term exposure to the atmosphere and moisture, and the effects of chemical species generated by corona discharge. , has not been sufficiently investigated so far. For example, it is known that if a device is left for more than a month, it will be affected by moisture and its receptive potential will drop significantly. On the other hand, amorphous silicon carbide (hereinafter referred to as a-8iC:H)
Regarding its manufacturing method and existence, Ph1losophical Magazine
) + Vol. 35' (1978), etc., and its characteristics include high heat resistance and surface hardness, and a high dark resistivity (10 to 10 Ω-cm) compared to a-8t:H. , the optical energy gap is 1 depending on the carbon content.
．． It is known that it varies over a range of 6 to 2.8 eV. An electrophotographic photoreceptor combining such a-8iC:H and a-8t:H has been proposed, for example, in Japanese Patent Application Laid-open No. 17952/1983. According to this, the a-8i:H layer is used as a charge generation layer, and the first a-8iC:
H layer is formed, and a second B-8 layer is formed on the back surface (support electrode side).
An iCSH layer is formed to provide a photoreceptor with a three-layer structure. The inventors of the present invention particularly studied photoreceptors using a-8iC:H and found that conventional photoreceptors have the following drawbacks. That is, when light reaches the charge transport layer (the above-mentioned second a-8iC:H layer) during light irradiation, optical fatigue occurs in the charge transport layer and localized levels that trap carriers are formed, resulting in the formation of black paper. It is necessary to increase the thickness of the charge generation layer to prevent light from reaching the charge transport layer, as this causes fluctuations in potential, fluctuations in blank potential, and increases in residual potential. If the thickness is large, the state of the interface between the charge generation layer and the charge transport layer will greatly affect the movement of photogenerated carriers in the charge generation layer. Specifically, the charge generation layer itself is doped with a small amount of impurities (for example, boron) from the viewpoint of sensitivity, etc., so carriers (holes) are inherently difficult to move. It is thought that the larger the film thickness, the more the holes will move to a predetermined position, and the arrival rate of holes will be greatly reduced, especially if the interface between the two layers is in poor condition. Furthermore, if the optical energy gap existing between the two layers is large, carriers generated within the photoconductive layer during light irradiation cannot sufficiently overcome the energy barrier existing between the charge generation layer and the charge transport layer. However, the photosensitivity may become insufficient. However, even if the optical energy gap is small (0.3 eV or less), it is an unavoidable problem that the hole mobility becomes insufficient for the reasons described above. Photoreceptors that have been proposed so far include gradients in which the amount of carbon is continuously changed between the charge generation layer and the charge transport layer, as in, for example, Utility Model Application Publication Nos. 57-23543 and 57-23544. One with layers is known. but,
In reality, it is difficult to continuously change the composition with good reproducibility, and during mass production, it is even more difficult to change the composition continuously with good reproducibility. It is also known that a surface-modified layer is provided on the surface of the photoreceptor, but a single-layer surface-modified layer does not provide satisfactory performance in terms of high sensitivity and mechanical strength. First, it is desired to improve carrier injection at the interface between the two layers, and to improve band bending and adhesion between the charge generation layer and the surface modification layer. C1. Purpose of the invention The purpose of the present invention is to achieve high sensitivity (particularly to improve edge cutting under a low electric field), have a low residual potential, and provide a charge generating layer.
It is an object of the present invention to provide a photoreceptor that has improved adhesiveness between charge transport layers, increased mechanical strength, and has high durability. 29 Structure of the invention and its effects, that is, the present invention comprises a charge transport layer made of amorphous hydrogenated and/or halogenated silicon containing oxygen atoms and doped with an element of Group 1IIa of the periodic table; a charge generation layer provided on the transport layer and made of amo/l/7a hydrogenated and/or halogenated silicon;
An intermediate layer ( (This intermediate layer may consist of a plurality of layers.) and (desirably, further includes a surface protection layer provided on the charge generation layer and made of an inorganic insulating material). It is. According to the present invention, since the intermediate layer C having an intermediate composition is provided between the charge transport layer and the charge generating layer, especially the intermediate layer having a substantially constant composition without continuously changing the composition, The carriers generated in the charge generation layer can be injected into the charge transport layer with high injection efficiency, and the formation of such an intermediate layer can be facilitated, thereby achieving both mass production. Additionally, if a surface protective layer made of an inorganic insulating material is provided on the charge generation layer, it will be resistant to mechanical damage, will not deteriorate image quality due to white streaks, etc., and will have excellent printing durability. Become. Furthermore, in the present invention, by providing an intermediate layer between the surface protective layer and the charge generation layer, it is possible to provide a photoreceptor with high performance in terms of mechanical strength and image blurring, thereby providing high sensitivity and high performance. A photoreceptor with durability and high image quality can be obtained. In addition, if a blocking layer is further provided, high charging ability can be realized, and in practical use, it will not put a burden on the process and development characteristics, and further high image quality and high durability can be achieved. Furthermore, since the charge transport layer also contains oxygen atoms and is doped with the Ha group element of the periodic table, the potential holding ability is improved and the mobility of photocarriers is also improved. E. Examples Hereinafter, the present invention will be explained in detail with reference to examples. FIG. 1 shows an a-8t electrophotographic photoreceptor 39 for positive charging according to this embodiment. This photoreceptor 39 is M
It has a structure in which a P-type blocking layer 44, a charge transport layer 42, an intermediate layer 47, a charge generation layer 43, and a surface protection layer 45 are laminated on a drum-shaped conductive support substrate 41 such as .゛ The charge blocking layer 44 is
It consists of amorphous hydrogenated and/or halogenated silicon (a-SiO: H/X) which is heavily doped with group IIa elements (eg boron). The charge transport layer 42 is made of amorphous hydrogenated and/or halogenated silicon (a-8
iO: H/X). The middle layer 47 is
Although it is made of a-8iO:H/X similar to the charge transport layer 42, the content of 0 is smaller than that of the charge transport layer 42. The charge generation layer 43 is made of amorphous hydrogenated and/or halogenated silicon (A-8T:
H/X). The surface protection layer 45 is made of an insulating inorganic material, for example A40s.
,Taxes,Cent,Zr0t,Tilt
, MgO. It consists of ZnOlPbO%MgF, ZnS, etc. Next, each of the above layers will be explained in more detail. 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 an a-8t:H surface, it is easily affected by humidity, air, ozone atmosphere, etc., and the potential characteristics change significantly over time. In addition, since the layer 45 has a high surface hardness, it has abrasion resistance during processes such as development, transfer, and cleaning, and also has good heat resistance, so a process that applies heat such as adhesive transfer can be applied. . Further, the thickness of the surface layer 45 is preferably selected within the range of 400A≦t≦500OA (especially 400A≦t≦200OA. In other words, when the thickness exceeds 500OA, the residual potential vR becomes high. In addition, the photosensitivity also decreases, and the good characteristics as an a-8i photoreceptor are easily lost.
Furthermore, if the film thickness is less than 400 A, charges will no longer be charged on the surface due to the tunnel effect, resulting in increased dark decay and decreased photosensitivity. Regarding the charge generation layer 43, in order to improve the charging ability,
It is also possible to increase the resistance of the charge generation layer and improve carrier mobility. For this purpose, the charge generation layer may be made intrinsic. In this case, CB=
L ) / CSiH4'l = 0.01 to 10 capacity - is better, 0.05 to 5 capacity - is even better, 0
．． 07-3 capacity is optimal. Further, the thickness of the charge generation layer is preferably 2 to 15 μm. If the thickness of the charge generation layer 43 is less than 2 .mu.m, the photosensitivity will not be sufficient and light will easily penetrate into the lower layer, and if it exceeds 15 .mu.m, the residual potential will increase, which is unsatisfactory for practical use. The intermediate layer 47 is provided to improve carrier injection efficiency, and its composition is 0.01%≦

[0]≦40% is good, 0.01chi≦(0)≦20% is even better, and 0.01chi≦[O]≦15chi is optimal. However, the content of 0 is less than that of the charge transport layer 42 (preferably 1/6 to 576 of the content of the charge transport layer). This intermediate layer 47 is preferably lightly doped with a Ha group element of the periodic table, for example, during glow discharge decomposition described later.
= H-'l/CSiH,) = 0.1~100
A capacity of 4 is good, a 0.5 to 50 capacity is even better, and a 1 to 20 volume tpP is optimal. Further, the thickness of the intermediate layer 47 is preferably 0.01 to 2 μm, but if it is less than 0.01 μm, the effect will be weak;
If it exceeds this value, the sensitivity tends to decrease. This intermediate layer can also be formed of two or more layers. The charge transport layer 42 may be made intrinsic in order to optimize charging ability and sensitivity. The doping amount for making it intrinsic is CBe H-) / C5iH4) = 0.1 to 1
00 volume fkpI]l is good, 0.5 to 50 volume is even better, and 1 to 20 volume is optimal. The thickness of the charge transport layer is preferably 5 to 50 μm, and preferably thicker than the charge generation layer 43. Further, the composition of the charge transport layer 42 is 0.5 ≦

[0]≦4
0chi is good. Preferably 0.7%≦[o]≦2(1-
71', and 0.8%≦[o]≦15% is optimal. In addition, the charge blocking J'! In order to sufficiently prevent the injection of electrons from the substrate 41 and to improve sensitivity and charging ability, 44 is doped with an element of Group 1IIa of the periodic table (for example, boron) by glow discharge decomposition to form a P-type (or even P-type). The doping amount is, for example, CB! )(-:] /
CSiH4:l = 10~10.000 capacity 4 is good, 100~5000 capacity Hayabusa is even better, 5oO~300
0 capacity is optimal. Further, the composition of the charge blocking layer 44 is 0.5chi≦[0
〕≦40chi is good, and 0.7chi≦

[0]≦20chi is good, and 0.8chi≦[O]≦15% is optimal. Further, the thickness of the blocking layer 44 is 0.01 to 10 μm.
Good. If it is less than 0.01 μm, the blocking effect will be weak, and if it exceeds 10 μm, the charge transport ability will tend to deteriorate. Note that each of the above layers contains hydrogen or halogen (e.g. fluorine).
It is necessary to contain In particular, the charge generation layer 43
The hydrogen content is indispensable in order to compensate for dangling bonds and improve photoconductivity and charge retention, and is preferably 10 to 30 H. This content range includes the surface modification layer 45, the intermediate layer 47, and the blocking layer 4.
4 and the charge transport layer 42 as well. Further, as an impurity for controlling the conductivity type, in addition to boron, elements of Group IIIa of the periodic table such as Al, Ga, In, and T1 can be used to make the conductivity type P-type. 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 set rotatably vertically in a vacuum chamber 52 of this device 51, and a heater 55 is used to rotate the substrate 41.
can be heated to a predetermined temperature from the inside.
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 electrode 57 and the substrate 41 by a high frequency power source 56. In addition, 62 in the figure is a supply source of 5iH- or gaseous silicon compound, 63 is a supply source of hydrocarbon gas such as CH, 64 is a supply source of nitrogen compound gas such as base, and 65 is an oxygen compound such as 01. 66 is a carrier gas supply source such as Ar; 67 is an impurity gas (for example, B, H,) supply source; 68 is a gas supply source;
is each flowmeter. In this glow discharge device, first, the surface of a support, for example, an M substrate 410, is cleaned and then placed in a vacuum chamber 52, and the gas pressure in the vacuum chamber 52 is set to 10
-' Torr, and the substrate 41 is heated to a predetermined temperature, particularly 100 to 350°C (preferably 100°C to 350°C).
50-300°C). Next, using a high-purity inert gas as a carrier gas, 5LH4 or a gaseous silicon compound, N2, Ol, etc. are appropriately introduced into the vacuum chamber 52, and high-frequency power is applied by a high-frequency power supply 56 under a reaction pressure of, for example, 0.01 to 10 Torr. Voltage (e.g. 13.56 M
Hz) is applied. By this, 42.47.4
3 (i.e., corresponding to the example of FIG. 1, for example). Then, a kl-0 layer 45 is deposited on the outermost surface by a known vacuum deposition method. In the above manufacturing method, the support temperature is set at 100 to 350°C in the step of forming the a-3i layer on the support, so the film quality (especially electrical properties) of the photoreceptor can be improved. . In addition, when forming the above a-8t photoreceptor photosensitive layer,
In order to compensate for dangling bonds, a fluorine atom, such as fluorine, is introduced in the form of 5iFa instead of or in combination with H, and a-8t: F,
a-8i: H: F%a-8iN: F. a-8iN: H: F, a-8iO: F, a
-8iO:H:F etc. can also be used. In this case, the amount of fluorine is preferably 0.5-10. The above manufacturing method is based on the glow discharge decomposition method, but there are also sputtering methods, ion blating methods, and methods in which Si is evaporated while introducing activated or ionized hydrogen in a hydrogen discharge tube ( In particular, Japanese Patent Application Laid-Open No. 56-78413 (Japanese Patent Application 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. An electrophotographic photoreceptor having the structure shown in FIG. 1 was prepared on a drum-shaped M support by a glow discharge decomposition method. That is, first, after cleaning the surface of a support, for example, a drum-shaped Al substrate 41 having a smooth surface, it is placed in a vacuum chamber 52 shown in FIG. 2, and the gas pressure in the vacuum chamber 52 is IO-@
Torr and exhaust the air, and keep the substrate 41 at a predetermined temperature, particularly 100 to 350°C (preferably 150°C).
Heat and hold at ~300'C). Next, high purity A
r gas is introduced as a carrier gas and the temperature is 0.5 Torr.
A high-frequency power with a frequency of 13.56 MHz was applied under a back pressure of 100 MHz, and a preliminary discharge was performed for 10 minutes. Then, S
i L and 0. A reaction gas consisting of , B, I(, is introduced, and the flow rate ratio is 1:1:1:(1,5X10"-
By glow discharge decomposition of the (Ar+SiH4+o, +BtHa) mixed gas of
O:H charge transport layer (CB, H= ) / CSiH
, ) = 10 capacity, [0) = 1 (1) 42, a-8
iO:H intermediate layer ((B, H・)/[SiH4]=9
(0)=5cm) 47 was sequentially formed into a film to a predetermined thickness at a deposition rate of 6 μm/11 r. Continuing, 0. The supply of SiH4 and current H6 was disassembled by discharging, and the thickness was reduced to 5.
μm a-8t: H layer (CB, H,) / (S
iH,)=0.1 capacity value)43 was formed. Subsequently, using a vacuum evaporation apparatus, M was used as an evaporation source, and 0. Al, O, surface protective layer 45 is formed by reactive vapor deposition under gas introduction.
Further, an electrophotographic photoreceptor was completed. As a comparative example, a photoreceptor without an intermediate layer was created. The structure of the photoreceptor thus produced is summarized in FIG. 3. Using each of these photoreceptors, various tests were conducted as follows. 0 Test Conditions - A machine modified from U-Bix 1600 MR (manufactured by Konishiroku Photo Industry Co., Ltd.) as follows was used. 1) Image exposure using a dichroic mirror (manufactured by Koshin Kogaku Co., Ltd.), sharply cutting long wavelength components of 620 nm or more. 2) The current flowing into the charging electrode is TR-N manufactured by Nagano Aichi Co., Ltd.
Output from 5 type high voltage power supply. -Measurement environment: room temperature 20℃, relative humidity 50℃. 0 Measurement conditions: The element content in the photosensitive layer was measured under the following conditions.
S (Auger Electron 5pectr
oscope') analysis was performed. 1) Measuring device: Birkin Elma PHIφ-600 type A
ES analyzer. 2) Sensitivity coefficient: Use the value listed in PHI Augeno 1 Handbook. 3) Measurement method: 3kV acceleration voltage, beam current 0.1μ
Measurement of Auger electrons during electron beam irradiation in A. The distribution in the film thickness direction was determined by Ar sputtering at an accelerating voltage of 3 kV and a beam current of 0.12 μA.・vw: Using the above U-Bix 1600 MR modified machine, the photoreceptor drum was dark-adapted for 12 hours, and immediately before image exposure, the surface potential of the photoreceptor was set to 550 V, and image exposure was performed for 2.71 uxesec. Surface potential of the photoreceptor immediately after exposure (exposure amount was measured with a 550-1 photometer (manufactured by EG&G)). Fist charging ability: surface potential immediately before development measured with a 360 S Image blur: X5.5 points English letters are blurred and unreadable. ○Clear fine line reproducibility. Durability: Many scratches occur after 200,000 copies. No scratches during 0.2 million copies. Δ: 1 to 10 scratches. The results are summarized in Figure 3. 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 3 show examples of the present invention, in which FIG. 1 is a sectional view of an a-8i photoreceptor, FIG. 2 is a schematic sectional view of a glow discharge device, and FIG. 3 is a schematic sectional view of a glow discharge device. 1 is a table showing characteristics of each photoreceptor. In addition, in the symbols shown in the drawings, 39......a-8i system photoreceptor 41...
...Support (substrate) 42 ...Charge transport layer 43 ...Charge generation layer 44 ...Charge blocking layer 45 ...
. . . Surface modified layer 47 . . . Intermediate layer.

Claims (1)

[Claims] 1. A charge transport layer made of amorphous hydrogenated and/or halogenated silicon containing oxygen atoms and doped with a Group IIIa element of the periodic table; or a charge generation layer made of silicon halide; provided between the charge transport layer and the charge generation layer, made of amorphous hydrogenated and/or silicon halide containing oxygen atoms, and containing oxygen atoms; an intermediate layer in which the charge transport layer is smaller than the charge transport layer.