JPS6283763A - Photosensitive body - Google Patents

Abstract

PURPOSE:To obtain a high image quality having a less tendency for generating a run of an image and a fade of an image by providing a surface protective layer composed of an amorphous hydrogenated and/or halogenated silicon contg. at least one kind selected among a carbon atom, an oxygen atoms and a nitrogen atom on the titled body. CONSTITUTION:The photosensitive body comprises the electric charge transfer layer 42 which is composed of the amorphous hydrogenated and/or halogenated silicon contg. a nitrogen atom and is doped with an element belonging to a group IIIa of the periodic table of the element, and the electric charge generating layer 43 which is composed of the amorphous hydrogenated and/or halogenated silicon and is provided on the charge transfer layer 42, and the intermediate layer 47 which is composed of the amorphous hydrogenated and/or halogenated silicon contg. the oxygen atom and contains less the oxygen atom than that of the charge transfer layer and is provided between the charge transfer layer and the charge generating layer, and the surface protective layer 45 which is composed of the amorphous hydrogenated and/or halogenated silicon contg. at least one kind selected among the carbon atom, the oxygen atom and the nitrogen atom, and is provided on the charge generating layer. Thus, the titled body having a less tendency for generating a deterioration of the image quality due to the generation of a white stripe and having a high performance against the fade of the image is obtd.

Description

[Detailed description of the invention]

B. Industrial Application Field The present invention relates to a photoreceptor, for example, an electrophotographic photoreceptor. BACKGROUND OF THE INVENTION Conventionally, as an electrophotographic photoreceptor, Se or As1 is added to Se.
Photoreceptors doped with Te, Sb, etc., and photoreceptors made of ZNO or CdS in a resin binder (bidispersion) are known. However, these photoreceptors have poor environmental pollution, thermal stability, and mechanical strength. On the other hand, an electrophotographic photoreceptor using amorphous silicon (hereinafter referred to as a-8t) as a matrix has been proposed in recent years. It has a so-called dangling bond in which the bond has been 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, the above-mentioned defects are compensated with hydrogen atoms (6) to form Sll-nee H bonds (=therefore, fill the dangling bonds. Such amorphous hydrogenated silicon (hereinafter referred to as a-8
1: Referred to as H. ) has a resistivity of 10 to 109Ω in the dark.
-10,000 times lower than that of amorphous Se. 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. In addition, photoreceptors with a-8i:H surfaces are susceptible to surface chemical damage, such as long-term exposure to the atmosphere or moisture, and the effects of chemical species generated by corona discharge. (stability); has not been sufficiently investigated to date.
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, there are two types of amorphous silicon carbide (hereinafter referred to as a-8iC:H), and their manufacturing method and existence are covered by Philosophical Magazine.
ine L Vol. 35 (1978), etc., and its characteristics include high heat resistance and surface hardness, and a high dark resistivity (10 to 10
Ω-crn) and that the optical energy gap changes over a range of 1.6 to 2.8 eV depending on the amount of carbon. An electrophotographic photoreceptor in which such a-8iC:H and a-8t:H are combined is proposed in, for example, Japanese Patent Application Laid-Open No. 57-17952 (:). According to this, the a-8t:H layer is As a charge generation layer, on this light-receiving surface, a first a-8iC:
H layer is formed, and a second a-8 is formed on the back surface (support electrode side).
As a result of investigating a three-layer structure by forming an iC:H layer, it was discovered that the conventional photoreceptor has the following drawbacks. In other words, during light irradiation! = Charge transport layer (the above second
When the light reaches the a-8iCCH layer of To prevent light from reaching the charge transport layer, it is necessary to increase the thickness of the charge generation layer. The state of the interface with the charge transport layer greatly influences the movement of photogenerated carriers in the charge generation layer. Specifically, the charge generation layer itself is free from impurities (such as boron) from the viewpoint of sensitivity. Because the amount of doping is small, carriers (holes) originally move; however, in addition to this, if the thickness of the charge generation layer increases, the holes move further to a predetermined position. In particular, if the interfacial condition between the above two layers is poor, the arrival rate of holes is thought to be greatly reduced.Moreover, if the optical energy gap existing between the two layers is large, during light irradiation (= However, if the optical energy gap is small, the carriers may not be able to sufficiently overcome the energy barrier that exists between the charge generation layer and the charge transport layer, resulting in insufficient photosensitivity. Even if the hole mobility is insufficient (even below 0.3 aV), it is an unavoidable problem that the hole mobility becomes insufficient due to the above-mentioned reasons. , No. 57-23544, etc.;
: It is known that a gradient layer with a continuously varying carbon content is provided between a charge generation layer and a charge transport layer. However, 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. Although it is known that a surface-modified layer is provided, a single-layer surface-modified layer does not provide satisfactory performance in terms of high sensitivity and mechanical strength. It is desired to improve carrier injection at the interface and to improve band bending and adhesion between the charge generation layer and the surface-modified layer. In addition, the residual potential is low, the adhesion between the charge generation layer and the charge transport layer is improved, the mechanical strength is increased, and high durability is possible. An object of the present invention is to provide a photoreceptor that can improve the mechanical strength of the side and obtain high image quality without image deletion or image blurring. a charge transport layer comprising amorphous hydrogenated and/or halogenated silicon and doped with an element of group IIIa 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; is smaller than the charge transport layer (this intermediate layer may be composed of a plurality of scraps); provided on the charge generation layer, and at least one of carbon atoms, oxygen atoms, and nitrogen atoms;
a surface protective layer made of amorphous hydrogenated and/or halogenated silicon containing species (preferably further provided between the charge generation layer and the surface protective layer) containing carbon atoms, oxygen atoms and nitrogen atoms; An intermediate layer made of amorphous hydrogenated and/or halogenated silicon containing at least one of the above, and containing more silicon atoms than the surface protective layer (this intermediate layer may be composed of a plurality of layers). ) and ).According to the present invention, since the surface protective layer contains at least one kind of atoms of carbon, nitrogen, and oxygen, it becomes resistant to mechanical damage. , there is no deterioration in image quality due to white streaks, etc., and the printing durability is excellent.Furthermore, in the present invention, an intermediate layer having an intermediate composition (particularly (2) An intermediate layer with a nearly constant composition that does not change continuously, so carriers generated in the charge generation layer can be injected into the charge transport layer with high injection efficiency due to light irradiation (2). At the same time, providing an intermediate layer between the surface protective layer and the charge generation layer provides mechanical strength and high performance against image blurring. It is possible to provide a photoreceptor with high sensitivity, high durability, and high image quality.In addition, if the blocking layer is added (bifurcated), high charging ability will be achieved, and process and Even higher image quality and higher durability are possible without putting a burden on the development characteristics.Furthermore, the charge transport layer also contains oxygen atoms (2. It is doped with an element from group 111a of the periodic table). Therefore, the potential holding ability is improved and the mobility of photocarriers is also improved. This shows an A-8T electrophotographic photoreceptor 69. This photoreceptor 69 is a
A P-type blocking layer 44, a charge transport layer 42, an intermediate layer 47, a charge generation layer 4!1, an intermediate layer 46, and a surface protection layer 45 are formed on a drum-shaped conductive support substrate 41 such as T. It consists of a layered structure. The charge blocking layer 44 is made of amorphous hydrogenated and/or halogenated silicon (a-3iO:H/X) heavily doped with an element of group IIIa of the periodic table (eg, boron) and containing O. The charge transport layer 42 is formed of the periodic table 1IIa.
It consists of amorphous hydrogenated and/or hydrogenated silicon (a-8iO:H/X) that is lightly doped with a group element (for example boron) and contains 0. The intermediate layer 47 is made of a-8iO:H/X similar to the charge transport layer 42.
However, the content of 0 is smaller than that of the charge transport layer 42. The charge generation layer 46 is made of amorphous hydrogenated and/or halogenated silicon (a-
8t:H/X). The intermediate layer 46 includes C,
Amorphous hydrogenated and/or halogenated silicon containing at least one of N and O (a-stc:
H/X, a-8iCO:H/X, a-8iN:H/X. a-S i No: H/X or a-8iO:H/
X), but the content of St is higher than that of the surface protective layer 45. Furthermore, the surface protective layer 45
a-8i C:H/X, a-8i Co similar to 6
:H/X, a-8iN:H/X, a-8iNo:
Consists of H/X or a-810:H/X. Next, each of the above layers (: will be described in more detail. The above layer 45 is essential for modifying the surface of the photoreceptor and making the A-8I photoreceptor practically excellent. In other words, it enables the basic operations of an electrophotographic photoreceptor: charge retention on the surface and attenuation of the surface potential due to light irradiation.Therefore, the repetitive characteristics of charging and light attenuation are extremely ζ: It becomes stable and good potential characteristics can be reproduced even if left for a long period of time (for example, over 1 month).On the other hand, in the case of a photoconductor with an a-8i:H surface (
= is easily affected by humidity, air, ozone atmosphere, etc.
Changes in potential characteristics over time become significant. In addition, since the layer 45 has a high surface hardness, it has abrasion resistance during processes such as development, transfer, and cleaning (2), and also has good heat resistance, so it is not possible to apply heat-applying processes such as adhesive transfer. In order to comprehensively exhibit the above-mentioned excellent effects, it is important to select the composition of the layer 45. That is, when containing carbon atoms, st+c-to. atomic% (hereinafter referred to as atomic % is simply expressed as %), then 1%≦[03690%, furthermore 10%
It is desirable that ≦[03570%. This C content makes the specific resistance a desired value, and the optical energy gap becomes approximately 2.5 eV or more, and the irradiated light is a-8i:H due to the so-called optically transparent window effect for visible and infrared light. It becomes easier to reach the layer (charge generation@) 43. However, if the C content is 1% or less, disadvantages such as mechanical damage occur, and the specific resistance tends to fall below a desired value, and part of the light is absorbed by the surface layer 45, reducing the photosensitivity of the photoreceptor. It becomes easier to do. Furthermore, if the C content exceeds 90%, the amount of carbon in the layer increases, which tends to cause loss of semiconductor properties and also tends to reduce the deposition rate when forming an a-8iC:H film by glow discharge method. , C content is preferably 90% or less. Similarly:: For layer 45 containing nitrogen or oxygen, 1%≦
(N)590% (furthermore, 10%≦(N)670%) is good, and 0%<

[0]≦70% (even 5%≦

[0]≦3
0%) is better. Further, the Si content of the surface layer 45 is S1+C (or N,
0) -100%, 10-80% is good, 20-100%
The thickness of the surface layer 45 is 4ooX≦t≦soo. Select within the range (especially (=400X≦t≦2000X). In other words, if the film thickness exceeds 5ooo When thicker than 400X (=
In this case, due to the tunnel effect, charges are no longer charged on the surface (= no longer charged), resulting in an increase in dark decay and a decrease in photosensitivity. It is installed to improve the quality and stabilize the image.
The above content ranges of C, N, and 0% Si are similarly applied to the intermediate layer 46, but the Si content of the intermediate layer 46 is higher than that of the surface layer 45. Note that this middle layer is 2
More than one layer can be provided. The thickness of this intermediate layer 46 is preferably 50 to 5000X, but if the thickness is 5000A, the same phenomenon as described above is likely to occur, and if it is less than soX, the effect as an intermediate layer will be poor. Regarding charge generation @43, in order to improve charging ability,
It is also possible to increase the resistance of the charge generation layer and improve carrier mobility. Therefore, (2) may make the charge generation layer intrinsic. In this case, during glow discharge decomposition described below: (2)
tHa)/(SiH4)-0.01~10 volume i ppm
It is best to have a capacitance of 0.05 to 5 ppm (more preferably 0.07 to 3 ppm). Also, the charge generation layer is preferably in the form of a 2 to 15 μm groove. If 46 is less than 2μ, the photosensitivity will not be sufficient and light will easily penetrate into the lower layer, and if it exceeds 15μ, the residual potential will increase, making it unsatisfactory for practical use. It is provided to increase efficiency, and its composition is 0.01%≦

[0]≦40% is good, 0.01%≦(0)520% is better (:yo<, 0.01%≦(0)515% is optimal. However, the content of 0 is the charge The content of the intermediate layer 47 is less than that of the transport layer 42 (preferably 1 to 5/6 of the content of the charge transport layer).The intermediate layer 47 is preferably lightly doped with an element of group 11a of the periodic table, for example, as described below. During glow discharge decomposition (
Bt mountain 1:)/ (s t H4) -o, 1 to 10
It is best to set it to 0 volume ppm, and 0.5 to 50 volume ppm.
is even better, and 1 to 20 ppm by volume is optimal. The thickness of the intermediate layer 47 is preferably 0.01 to 2 .mu.m. However, if it is less than 0.01 .mu.m thick, the effect is weak, and if it exceeds 2 .mu.m., 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 (B tHe ) ABI H4) = 0.1 to 1
00 volume ppm is good, 0.5 to 50 volume ppm is even better, and 1 to 20 volume ppm is optimal. The thickness of the charge transport layer is preferably 5 to 50 μm, and the charge generation layer 43
It is better to make it thicker. Further, the composition of the charge transport layer 42 is 0.5%≦

[0]≦40% is good, preferably 0
．． 7%≦

[0]≦20%, and 0.8%≦[0351
5% is optimal. Further, the charge blocking layer 44 sufficiently prevents injection of electrons from the substrate 41 and improves sensitivity and charging ability (
Yu is doped with an element of group 1 Oa of the periodic table (for example, poron) by glow discharge decomposition to convert it into a P type (or even a P+ type).
The doping amount is, for example, CB, I(,)/(Sta
,) Snow 10~10,000 ppm is good, 100~
5000 ppm by volume is even better, and 500 to 3000 ppm by volume is optimal. Further, the composition of the charge blocking layer 44 is 0.5%≦[0
]≦40% is good, even (20.7%≦

[0]≦20% is good, 0.8%≦

[0]≦15% is optimal. Further, the thickness of the blocking layer 44 is preferably 0.01 to 10 μm thick. 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 especially. The hydrogen content in the charge generation layer 46 is essential to compensate for dangling bonds and improve photoconductivity and charge retention, and is preferably 10 to 30%. This content range is 45 for the surface modified layer and 46.4 for the intermediate layer.
7. The same applies to the blocking layer 44 and the charge transport layer 42. In addition, as an impurity to control the conductivity type, P
In addition to poron, elements of the La group of the periodic table such as At, Ga, In, and Tt can be used for molding. Next (=, the method for manufacturing the above-mentioned photoreceptor (for example, drum-shaped) and its device (glow discharge device) will be explained using two diagrams. In the vacuum chamber 52 of this device 51, the drum-shaped substrate 41 is vertically The substrate 41 is set rotatably on the heater 55.
A cylindrical high-frequency electrode 57 with a gas outlet 53 is disposed opposite to and around the substrate 41 to heat it from the inside to a predetermined temperature. A glow discharge is generated. In the figure, 62 is a supply source of S i H4 or a gaseous silicon compound, 66 is a supply source of hydrocarbon gas such as CH,
64 is N. 65 is a supply source of oxygen compound gas such as 02, 66 is a carrier gas supply source such as Ar,
67 is an impurity gas (for example, B, H,) supply source, and 68 is each flow meter. In this glow discharge device, first, after cleaning the surface of the support, for example, the At substrate 41:
2 inside the vacuum chamber 52;: the gas pressure inside the vacuum chamber 52 is 10
Torr (adjusted and evacuated, and heated the substrate 41 to a predetermined temperature, particularly 100 to 350°C (preferably 1
50 to 300° C.) (maintained under heating. Next, using a high-purity inert gas as a carrier gas, Si H4 or a gaseous silicon compound, N, , O, etc.
2, and a high frequency voltage (for example, 13 Torr) is applied by a high frequency power supply 56 under a reaction pressure of, for example, 0.01 to 10 Torr.
56MHz) 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 P type a-sio:a, type SlO:H, i type SiO
:H, a-8i:H, a-8iO:H, a-8iO:H
are deposited successively (i.e. corresponding to the example of FIG. 1, for example) on the substrate as layers 44, 42, 47, 46, 46, 45 as described above. In the above manufacturing method, the support temperature is set at 100 to 350°C in the step of forming the a-8t 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,
To compensate for dangling bonds (the second is H
Instead, or in combination with H, a halogen atom, such as fluorine, is introduced in the form of SiF4, etc., and a-8i:, F%a
-8t:H:F, a-8IN:F. a-8iN:H:F, a-810:F, a-8iO:H
:F etc. can also be used. In this case, the amount of fluorine is o
, s~10% is desirable. The above manufacturing method is based on the glow discharge decomposition method C2, but other methods (also include sputtering method, ion blating method, and evaporation of St under the introduction of activated or ionized hydrogen in a hydrogen discharge tube) method (in particular, Japanese Patent Application Laid-Open No. 56-78413 (Patent Application No. 54-15) by the present applicant)
The above photoreceptor can also be manufactured by the method of No. 2455). Hereinafter, the present invention will be described with reference to specific examples. By glow discharge decomposition method, the first
An electrophotographic photoreceptor having the structure shown in the figure was manufactured. That is, first, after cleaning the surface of a support, for example, a drum-shaped At substrate 41 having a smooth surface, it is placed in a vacuum chamber 52 shown in FIG.
Torr, and exhaust the air, and keep the substrate 41 at a predetermined temperature, particularly 100 to 350°C (preferably 150 to 350°C).
Heat and maintain at 300°C. Then, high-purity Ar gas was introduced as a carrier gas, and the frequency was 13.56 MH under a back pressure of 0-5 Torr.
A high frequency power of z was applied and preliminary discharge was performed for 10 minutes. Next, a reaction gas consisting of SiH4, O,, B, and H is introduced, and the (Ar+S i H4+0.+B, H6) mixed gas at a flow rate ratio of 1:1:1:(1.5×10 ) is subjected to glow discharge decomposition. By doing so, the P-type a-8iO:H layer 44, which has a charge blocking function, and the a-8iO:H
Charge transport layer ((BtHs:l/C8i H4)=1
0 volume tppm, (0)-10%) 42, a-8iO:
H intermediate layer (However, (Bt Ha) / (S i Ha)
= 9 PPm,

[0]-5%) 47 to 6μ/hr
A film was formed to a predetermined thickness at a deposition rate of . continuation,
The supply of Ol was stopped, and SiH, B, and H were decomposed by discharge, and an a-3i:H layer with a thickness of 5 μm (however, (BzHe:l/
(S i Ha) -0.1 ppm by volume) 43 was formed. Subsequently, Ol is supplied for glow discharge decomposition,
Form an a-3iO:H intermediate layer (however, [O]-20%) 46, and further form an a-810:H surface protective layer (however, (0) = 4).
0%) 45 was further provided to complete the electrophotographic photoreceptor. 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, the following two tests were conducted. O Test Conditions - A machine modified from U-Bix1600MR (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℃, humidity ratio 50%. O measurement conditions: The element content in the photosensitive layer was measured using AES under the following conditions.
(Auger Electron 5pectros
copy ) analysis was performed. 1) Measurement Pa: Perkin Elma m PHI φ-6
00 type AES analyzer. 2) Sensitivity coefficient: Use the value described in PHI's Auger Handbook. 3) Measurement method: 3KN 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 with an accelerating voltage of 3 KV and a beam current of 0.12 μA.・vw: Using the above U-Bi:c1600MR modified machine, set the photoreceptor drum so that the surface potential of the photoreceptor becomes ssov just before image exposure after dark adaptation for 12 hours.
Surface potential of the photoconductor immediately after image exposure of tuxesec (exposure amount is 550-1 type photometer (manufactured by EG, !loG)
). -Charging ability: Surface potential immediately before development measured with a 360 SX type electrometer (manufactured by Trek) under conditions of no exposure to photoconductor inflow current of 150 μA. Image pocket: X5.5 points English letters are crushed and unreadable. ○Clear fine line reproducibility. Durability: × Many scratches occur due to multiple copies. No scratches during 0.2 million copies. △Scars occurred in 1 to 10 places. 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. Further 1: As shown in the table below, a photoreceptor according to the present invention was prepared in which the intermediate layer on the surface side was composed of two layers. The electrophotographic performance of this photoreceptor was still good (E
g, opt is the optical energy gap).

[Brief explanation of drawings]

1 to 3 show embodiments of the present invention, in which FIG. 1 is a cross-sectional view of an A-8I-based ill-sensitivity light, FIG. 2 is a schematic cross-sectional view of a glow discharge device, and FIG. 3 is a schematic cross-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, 69......a-81 series photoreceptor 41.
......Support (substrate) 42...
Charge transport layer 46 Charge generation layer 44 Charge blocking layer 45
......Surface modified layer 46.47...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; is smaller than the charge transport layer; an intermediate layer formed on the charge generation layer and made of amorphous hydrogenated and/or halogenated silicon containing at least one of carbon atoms, oxygen atoms, and nitrogen atoms; A photoreceptor having a surface protective layer.