JPS60235155A - Photosensitive body - Google Patents

Abstract

PURPOSE:To stabilize high acceptance potential and to obtain superior light fatigue resisting characteristics by forming an electrostatic charge blocking layer, a charge transfer layer, and a charge generating layer, each layer being of a specified a-Si type, on a substrate in succession, and incorporating a specified amt. of O in said blocking layer. CONSTITUTION:The charge blocking layer 44 made of a-SiN, the charge transfer layer 42 made of a-SiC and/or a-SiN, and the charge generating layer 43 made of a-Si, Si of each layer hydrogenated and/or fluorinated, are formed on the substrate 41 in this order from its side. The layer 44 contains O in an amt. of 1- 20atomic% of Si+C+O, and further, N in an amt. of 30-70atomic%. The layer 42 contains C or N in an amt. of 10-30atomic%. A surface modifying layer 45 made of hydrogenated and/or fluorinated a-SiC or a-SiN contg. C in an amt. of 10-70atomic% is formed on the layer 43. The contact of O in the blocking layer 44 can enhance dark resistance in spite of having charge blocking ability and lower its temp. dependence, thus enhancing the usable upper limit of a photosensitive body.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Industrial Application Field The present invention relates to a photoreceptor, such as an electrophotographic photoreceptor.

2. Prior art Conventionally, as an electrophotographic photoreceptor, Se, or Se and As,
Photoreceptors doped with Te, Sb, etc., photoreceptors in which ZnO or CdS is dispersed in a resin binder, and the like are known. However, these photoreceptors have problems in (2) environmental pollution, thermal stability, and mechanical strength.

It is being proposed. a-3i has a so-called dangling bond in which the bond of 5i-81 is broken, and many localized levels exist in the energy gear due to this defect. For this reason, hopping conduction of thermally excited carriers occurs, resulting in low dark resistance, and photoexcited carriers are trapped in localized levels, resulting in poor photoconductivity. Therefore, -1-
The dangling bonds are filled by compensating for the defects described in item 1 with hydrogen atoms (+() and bonding H to Si.

Such amorphous hydrogenated silicon (hereinafter referred to as a-3
It is called i:H. ) resistivity in the dark is 1♂~10'l
Ω-em, which is about 1 compared to amorphous SC.
It's even lower than 1/10,000. Therefore, a photoreceptor made of a single layer of a-3i:11 has problems in that the dark decay rate of the surface potential is high and the initial charging potential is low. But on the other hand,
Since the resistivity is greatly reduced when irradiated with light in the visible and infrared regions, an electrophotographic copying machine incorporating a photosensitive A-5T type photoreceptor has been 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 a first part of the 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 reflection mirror 6 is provided so as to be movable in a straight line in the left and right direction of the drawing. A second mirror unit 20 for keeping the optical path length constant 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 and is reflected as an image carrier. The light enters the photosensitive drum 9'' in a slit shape. Around the drum 9, there are a corona charger 10, a developing device 11, and a transfer section 12.
, a separating section 13, and a cleaning section 14 are arranged, and the paper is fed from the paper feed box 15 through each paper feed roller 16, 17 (3).
) After the toner image is transferred from the drum 9, the copy paper 18 that is fed is further fixed in a fixing section 19 and discharged onto a tray 35. In the fixing section 19, the developed copy paper is passed between a heating roller 23 having a built-in heater 22 and a pressure roller 24 to perform a fixing operation.

However, photoreceptors with a-3i:H expression 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. This has not been sufficiently studied so far.

For example, it is known that if a device is left in the oven for less than a month, it will be affected by humidity and its receptive potential will drop significantly. On the other hand, amorphous hydrogenated silicon carbide (hereinafter a-S
iC: Referred to as IT. ), its manufacturing method and existence are reported in “Phil, la 3° Vol. 35 (197
8), etc., and its characteristics include high heat resistance and surface hardness, high dark resistivity (ho'~I +1'Ω-cm) compared to a-3ill, and carbon Optical energy gap is 1.6~2.8e
, V is known to vary over a range of . However, there is a drawback that long-wavelength sensitivity becomes poor because the carbon content causes the rays to expand.

An electrophotographic photoreceptor combining such a-3iC:H and a-3t:H has been proposed, for example, in Japanese Patent Laid-Open No. 127083/1983. According to this, a-3isI
A functionally separated two-layer structure was created in which the f layer was used as a charge generation (photoconductive) layer, and the a-3iC:H layer was provided as a charge transport layer below this charge generation layer, and the upper layer a-3t:H It achieves photosensitivity in a wide wavelength range and improves the charging potential by using the lower layer a-3iC:H that forms a heterojunction with the a-3t:H layer. However, the dark decay of the a-3t:H layer cannot be sufficiently prevented, and the charging potential is still insufficient to be of practical use.

On the other hand, in JP-A-57-17952 and JP-A-57-52178, a first a-3ICsH layer is formed as a surface-modified layer on a charge generation layer made of a-3t:H, and on the back surface (
A second a-3iCsH layer is formed on the support electrode side) as a charge transport layer or a charge blocking layer.

(6) However, in known photoreceptors, a-3iC:
It has been found that the II charge blocking layer has the following problems.

That is, the known a-S i C: H is dark resistance ρ. Because of the large temperature dependence of ′? At A'/A, the retention characteristic of the 41-volt potential deteriorates, making it unusable for practical use, and moreover, image deletion is likely to occur. These defects may cause the charge blocking layer to be replaced with a well-known amorphous nitride 91 piece (a-3
The same problem occurs when the film is formed using iN).

3. OBJECTS OF THE INVENTION An object of the present invention is to provide a photoreceptor that can stably maintain a high charging potential (particularly under high temperature or high humidity) and has excellent optical fatigue properties.

4. Structure of the invention and its effects, that is, the photoreceptor according to the present invention has a charge generating and charge transporting layer made of amorphous hydrogenated and/or fluorinated silicon, and a charge transport layer made of amorphous hydrogenated and/or fluorinated silicon nitride. In a photoreceptor provided with a charge blocking layer, the charge blocking layer may be
atomic% of oxygen (however, the total number of atoms of silicon atoms, nitrogen atoms, and oxygen atoms is lQQatomic%.

).

According to the present invention, it is a functionally separated type photoreceptor, and since the charge blocking layer contains 1 to 20 atomic% of oxygen, it exhibits charge blocking ability.
・While ρ, effectively increases ρ. The power can be increased by keeping the temperature dependence (dp, /dT) small. If - the above oxygen-containing alcohol] at
If it is less than omic%, the effect of oxygen content will not be exhibited, and if it exceeds 20 atomic%, there will be too much oxygen and the carrier mobility, that is, (μτ) will be significantly reduced. Therefore, the oxygen content should be reduced to 1-20 atomic%.
It is essential to set the
It is desirable to set it to omic%.

5. Examples (7) Hereinafter, the present invention will be described in detail with reference to examples.

FIG. 2 shows an a-3i electrophotographic photoreceptor 39 according to this embodiment.
This shows that. This photoreceptor 39 is A7! Oxygen is added at 1 to 20 atomic concentration onto a drum-shaped conductive support substrate such as
A charge blocking layer 44 consisting of a-5iN:II containing % of a-5iC:H or a-3iN
: A charge transport layer 42 made of 11 and a charge generation layer 43 made of a-3t:H.
C: It has a structure in which a surface modified layer 45 made of an inorganic material such as II or a-5iN:11) or SIO□ is layered. The ratio to the resistivity during irradiation is sufficiently large as an electrophotographic photoreceptor, and the photosensitivity (particularly to light in the visible and infrared regions) is good.

In this photoreceptor 39, based on the present invention, a-S
iN: Oxygen atoms are added to the charge blocking layer 44 made of H to a total number of atoms of 5i-I-N+O of 100,100at
The content is 1 to 20 atomic% relative to 0%. Oxygen in this content range increases the charge blocking layer 42 (9) (8) even under high temperature (or high humidity), and stably maintains the charging potential holding ability of the photoreceptor.

The nitrogen atom content of the charge blocking layer 44 is 30 to 70
atomic% (total number of atoms of 5i +N is 100100
Let it be ato%. ), and the appropriate thickness is 400 to 4000 people.

Further, the carbon or nitrogen content of the charge transport layer 42 is 1
It is desirable that the content be 0 to 30 atomic% (the total number of atoms of Si+C (or N) is 00 atomic%).

Regarding the thickness of each layer described above, the charge generation layer 42 has a thickness of 1 to 1.
5μm3 locking layer 44 has 400 to 4000
It's better to do it with people. If the thickness of the charge generation layer 43 is less than 1 .mu.m, the light emission is insufficient, and if the charge generation is not achieved, the residual potential increases, making it unsatisfactory for practical use. Blocking layer 4
If the number of 4 is less than 400, the blocking effect is weak, and if it exceeds 4,000, the charge transport ability tends to be poor. The thickness of the charge transport layer 42 is preferably 10 to 30 μm.

The surface modification part 45 is a-3 modified by modifying the surface of the photoreceptor.
In order to make the i-type photoreceptor practically superior (10), it is preferable to provide it. 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 are always stable, and good potential characteristics can be reproduced even if left for a long period of time (for example, one month or more). a In the case of a photoreceptor with SI:II as the surface, /! l+! It is easily influenced by air, atmosphere, ozone atmosphere, etc., and potential characteristics tend to change over time. Also, a-81c: 1f or a-5iN: II
Since the surface modified layer 45 made of process can be applied.

In order to achieve such excellent effects comprehensively, a-
It is important to choose a carbon or nitrogen composition of 3iC:tl or a-3iN:II. That is, it is desirable that the carbon or nitrogen atom content (1) is 10 to 10s105Lo% when 5il-C (or N)=-100%. When the C or N content is 10% or more, the specific resistance described in will be the desired value, and the optical energy gap will be approximately 2.
．． It becomes more than OeV and becomes easily visible. However, C
Alternatively, if the N content is less than 10%, the specific resistance tends to be less than a desired value, and part of the light is absorbed by the surface 1945, and the photosensitivity of the photoreceptor tends to decrease. Furthermore, if the C or N content exceeds 70%, the amount of carbon or nitrogen in the layer increases, and semiconductor properties are likely to be lost, and the a-3iC:H film or a
-S i N: f (Since the deposition rate tends to decrease when forming a film by glow discharge method, the C or N content is 7
It is preferable to set it to 0% or less.

Also, a-S i C: H or a-3iN:HIW
45 membrane 11i Within the range of 400 people≦t≦5000 people (
In particular, it is important to select 400 people≦t<2000 people). That is, if the film thickness exceeds 5,000 layers, the residual weight level VR will be high and the photosensitivity will be decreased, and a-3
It does not easily lose its good characteristics as an l-based photoreceptor. In addition, if the film thickness is less than 400 mm, charges will not be transferred to the surface electrons due to the tunnel effect (11).
Therefore, an increase in lli attenuation and a decrease in photosensitivity occur.

Note that each layer in -12 must contain hydrogen.
! It is. In particular, the hydrogen content in the charge generation layer 43;
, is essential for compensating for dangling bonds and improving photoconductivity and charge retention, and has a content of 10 to 30
This content range, which is preferably atomic%, includes the surface modification layer 45, the blocking layer 44, and the charge transport layer 42.
The same is true.

Next, a method for manufacturing a photoreceptor (for example, a drum J2 shape) marked with "-" and its apparatus (glow discharge device + ¥) will be explained with reference to FIG.

Inside the vacuum chamber 52 of this device 51, a drum-shaped substrate 41
is set so as to be vertically rotatable, and the substrate 4 is heated by a heater 55.
1 can be heated to a predetermined temperature from the inside.

A cylindrical high frequency electrode 57 with a gas outlet 53 is arranged around and facing the substrate 4I, and a glow discharge is generated between the electrode 57 and the substrate 41 by a high frequency power source 56. In addition,
In the figure, 62 is a source of Si 114 or a gaseous (13) (12) silicon compound, 63 is a source of 02 or a gaseous oxygen compound, and 64 is a hydrocarbon gas such as CH or Nl.
65 is a supply source of a nitrogen compound gas such as N2, a carrier gas supply source such as Ar, 66 is a H2 gas supply source, and 67 is each flow meter. In this glow discharge device, first, the surface of a support, for example, an Al substrate 41, is cleaned, and then placed in a vacuum chamber 52, the voltage within the vacuum chamber 52 is adjusted to 0 Torr, and the air is evacuated. At the same time, the substrate 41 is heated and maintained at a predetermined temperature, particularly 100 to 350°C (preferably 150 to 300°C). Then, using a high purity inert gas as a carrier gas, SiH4 or a gaseous silicon compound, CH, (or N Th, group), 0
2 is appropriately introduced into the vacuum chamber 52, for example, 0.01 to 10
A high frequency voltage (for example, 13.56 MHz) is applied by a high frequency type tA56 under a reaction pressure of Torr. By this, upper a-3i jT-L a-3IC:H or a
-S i N :H above layer 44.42.43.4
5 (i.e., corresponding to the example of FIG. 2).

(14) In the above manufacturing method, the temperature of the support is set at 100 to 350°C in the T-culm in which the a-8i layer is formed on the support, so the film quality of the photoreceptor (especially the electrical 11) can be improved.

In addition, when forming the a-3i photoreceptor 15,
To make the dangling bond N (H), use II and 13j instead of
Introduced in the form of F4 etc., a-3i:F, a-3i:
II:a-5iN:F,, a-3iN:II:FXa-
3iC:F.

It can also be a-3IC:II:F. In this case, the amount of fluorine is desirably 0.5 to 10 atomic%.

In addition, the manufacturing method described in - is based on the glow discharge bone method 1 and 1 method, but in addition to this method 1, sputtering method,
Ion blating method, method of evaporating Si under introduction of hydrogen activated or ionized by hydrogen discharge (in particular, Japanese Patent Application Laid-Open No. 56-78413 (Japanese Patent Application No. 54-152455) by the present applicant) The above-mentioned photoreceptor can also be manufactured by the method described in ).

FIG. 4 shows a photoreceptor according to the present invention described in Japanese Patent Application Laid-Open No. 56-7.
This figure shows a vapor deposition apparatus used for fabrication by the vapor deposition method of No. 8413.

The Pel jar 71 is connected to a vacuum pump (not shown) via an exhaust pipe 73 having a butterfly valve 72, thereby pumping the inside of the Pel jar 71 at, for example, X&~10 Torr.
A high vacuum state of r is established. A substrate 41 is placed inside the Pelger 71 and heated to a temperature of 100 to 100°C by a heater 75.
Heat to 350°C, preferably 150-300”F,
At the same time, the DC power supply 76 applies 0 to -10k to the board 1.
V.

Preferably, a negative DC voltage of 1 to -6 kV is applied.

a-3i: To form the 11 layer 43, the exit is the substrate 41
While introducing active hydrogen and hydrogen ions into the Pel jar 71 from a hydrogen gas discharge tube 77 connected to the Pel jar 71 so as to face the substrate 41, a silicon evaporation source 78 provided so as to face the substrate 41 is heated. Upward +7) '/
+Open 7tarS. a-SiC: 141W
To form 42.45, silicon is evaporated under a supply of Cl-4. Further, the charge blocking layer 44 is
C) Instead of %, the silicon 78 may be evaporated while supplying N II and also OI. It is preferable to activate the C melon and NH3 via the discharge tube 7o and introduce them as appropriate.

(15) To illustrate the structure of the discharge tube 77, 70 described above, for example, as shown in FIG. For example, the fi? Consisting of a discharge space member 84 made of i-shaped glass, and a ring-shaped other electrode portion +A86 having an outlet 85 provided at the end of this JJk electropneumatic concave space member 84, the one electrode member 82
By applying a direct current or alternating current voltage between the electrode part +A86 and the other electrode part +A86, for example, hydrogen gas supplied through the gas cylinder generates a glow discharge in the hk electric space (3), which causes electrons to Active hydrogen consisting of energetically activated hydrogen atoms or molecules and ionized hydrogen ions are discharged from 111085. The discharge space member 82 in this illustrated example has a double pipe structure and allows cooling water to flow through it. (87.88 does not indicate the cooling water inlet and outlet 11.89, and the applied voltage is 60
0■, and the pressure in the discharge space 83 is about 10 Torr.

(17) (16) Hereinafter, the present invention will be described with reference to specific examples.

By glow discharge decomposition method, drum-shaped A7! An electrophotographic photoreceptor having the structure shown in FIG. 2 was prepared on a support.

That is, first, after cleaning the surface of the support, for example, a drum-shaped AIl substrate 41 having a smooth surface, it is placed in a vacuum chamber 52 in FIG. 3, and the gas pressure in the vacuum chamber 52 is set to 10T.
orr and evacuate, and the group M; 1.4
1 at a predetermined temperature, particularly 100 to 350°C (preferably 15°C
Heat and maintain at a temperature of 0 to 300°C. Next, high purity Ar
Gas was introduced as a carrier gas, and high frequency power with a frequency of 13.56 MH was applied under a back pressure of 0.5 Torr to perform preliminary discharge for 10 minutes. Then, S t
Conducting a reaction gas consisting of FL+, NH3 and 02,
(A r +S iHl with a flow rate ratio of 4:l:6:1
10N Hl + 0+) was formed, and then the supply of 0□ was interrupted and CH was replaced with NH5.

The charge transport layer 42 is supplied with 6 m! A film was formed to a predetermined thickness at a deposition rate of m/hr. Continuing, CH4, BzH6
, (18) Stop supplying 02, perform S i T (J discharge bone disintegration, predetermined thickness and !r glow discharge part, predetermined thickness a-3iC:I
Further, a surface protective layer 45 is provided, and an electrophotographic photoreceptor is completed. Using this photoconductor, a copying machine (U-Bix30
00 modified machine: Konishi Roku Photo Industry @) was used to produce images, and the resolution and IIM performance were good (1g image!'t)
The i! has a high R rating and clear images without fogging. I was beaten.

Further, even after repeated copying 200,000 times, stable and high quality images continued to be produced.

That is, during the test, the electrophotographic photoreceptor prepared as described in -1- was used with an electrometer model 5p-428 (
(manufactured by Kawaguchi Electric ■), the voltage applied to the discharge electrode of the charger was set to 16 kV, the charging operation was performed for 10 seconds, and the charged potential of the photoreceptor surface after this charging operation + Mr.
o(V), and after nl'l decay for 2 seconds, the charging potential is set to 1
Exposure f to halve the amount of irradiation light required to attenuate it to /2
lE ] / 2 (box -5ec). The light attenuation curve of the surface potential becomes flat at a certain finite potential (19) and may not become completely zero, but this potential is called the residual potential VI2 (V).

By varying the composition of each layer, the results shown in the table below were obtained. According to this, it can be seen that when the zero content of the charge blocking layer is set to 1 to 20 atomic %, the electrophotographic properties of the photoreceptor are greatly improved and the temperature dependence is reduced. Regarding the image quality, ◎ means the image is clear, ○ means the image is good, Δ means the image quality is practically acceptable, and × means the image quality is practically usable -1.
-Indicates whether the job is not possible.

(Margin below, continued on next page.) (20)

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a conventional electrophotographic copying machine. Figures 2 to 5 show embodiments of the present invention, in which Figure 2 is a cross-sectional view of an a-3i-based ill-sensitivity light, Figure 3 is a schematic cross-sectional view of a glow discharge device, and Figure 4 is a schematic cross-sectional view of a glow discharge device. A schematic cross-sectional view of the vacuum evaporation apparatus, and FIG. 5 is a cross-sectional view of the gas discharge tube. In addition, in the symbols shown in the drawings, 39.
・・・・a Si-based photoreceptor 41・・・・・・・・・・・・
・・・・・・・・・・・・・・・Support (substrate) 42
・・・・・・・・・・・・・・・・・・・・・・・・
・・Charge transport layer 43・・・・・・・・・・・・・・・・
......Charge generation layer 44...
・・・・・・・・・・・・・・・・・・Charge blocking layer 45・・・・・・・・・・・・・・・・・・
......Surface number a layer 55...
・・・・・・・・・・・・・・・・・・Heater 56...
・・・・・・・・・・・・・・・・・・・・・・・・
High frequency power supply 57・・・・・・・・・・・・・・・・・・
...... Electrode (22) 62-66...
・Each gas supply source 70.77・・・・・・・・・・・・・
......Gas discharge tube 78...
・・・・・・・・・・・・・・・・・・It is a source of evaporation. Agent Patent Attorney Hiroshi Aisaka (23) Naseikawa ~ 1 N

Claims (1)

[Claims] 1. A charge transport layer made of amorphous hydrogenated and/or fluorinated silicon carbide (and/or nitride) is provided under a charge generation layer made of amorphous hydrogenated and/or fluorinated silicon, Under this charge transport layer, an electric conductor 71 made of amorphous hydrogenated and/or fluorinated silicon nitride is provided.
In the 1:1 soaking layer, the total number of nitrogen atoms and oxygen atoms is 100 atomic%. ) (However, the total number of d1 atoms of silicon atoms and carbon or nitrogen atoms is 100100 ato%.) body. (1) 3. The charge blocking layer contains 30 to 70 atomic% nitrogen (however, the total number of silicon atoms and nitrogen atoms is 1
00100ato%. ) The photoreceptor according to claim 1 or 2, characterized in that: 4. Charge generation layer - consists of amorphous hydrogenated and/or fluorinated carbide (or nitride) silicon and has a carbon or nitrogen content of 10 to 70 atomic% (however, the total atomic amount of silicon atoms and carbon or nitrogen atoms) The photoreceptor described in Section 1.