JPS6385566A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance positive electrification performance of a photosensitive body by incorporating an element of group IIIa of the periodic table in each of a carrier injection blocking layer, a carrier transfer layer, and a carrier generating layer. CONSTITUTION:The carrier injection blocking layer 2, the carrier transfer layer 3a, the carrier generating layer 3b, and a surface protective layer 4 are successively laminated on a conductive substrate 1. The layer 2 is composed essentially of amorphous silicon containing an element of group IIIa of the periodic table, such as B, the layer 3a is made of amorphous silicon represented by the formula Si(1-z)Az, and the layer 3b is made of amorphous silicon carbide represented by the formula [Si(1-x)Cx](1-y)Ay. It is preferred that the layers 3a and 3b contain an element of group IIIa, too. In these formulae, A is H or halogen; 0.05<=z<=0.5; 0.01<=x<=0.9; and 0.05<=y<=0.5, thus permitting the obtained photosensitive body to be high in positive electrification performance and superior in durability.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more specifically, an electrophotographic photoreceptor that has excellent positive charging ability and excellent electrophotographic properties such as light attenuation and dark attenuation. body and its manufacturing method.

[Prior art and its problems]

In recent years, the development of ultra-high speed copying machines, laser beam printers, etc. has been actively progressing, and with this development, stable operating characteristics and durability are required of the electrophotographic photosensitive drums installed in these devices.

In response to this demand, hydrogenated amorphous silicon is attracting attention because of its excellent wear resistance, heat resistance, pollution-free property, and photosensitivity characteristics.

As an electrophotographic photoreceptor made of such amorphous silicon (hereinafter abbreviated as amorphous silicon), a laminated type photoreceptor as shown in FIG. 2 has been proposed.

That is, according to FIG. 2, a carrier injection blocking layer (2), an A-5I photoconductive layer (3), and a surface protection layer (4) are sequentially laminated on a conductive substrate (1) made of aluminum or the like. ,
This carrier injection blocking layer N (2) is formed to block the injection of carriers from the substrate (1) and to lower the residual potential, and the surface protective layer (4) is made of a highly hard material. This increases the durability of the photoreceptor.

However, according to this a-3i photoreceptor, the dark resistivity of the a-3i photoconductive layer (3) itself is 10"Ωcm or less, which increases the dark decay rate of this photoreceptor. At the same time, it becomes difficult to increase the charging capacity of the thread itself,
As a result, when this photoreceptor is used for long-distance copying, the previous image remains without being completely removed due to the optical memory effect, and the previous image appears when the next image is formed (ghost phenomenon). I have a problem to say.

Moreover, in the conventional photoreceptor made of a-Si shown in Fig. 2, the charging potential is as low as -400 to -5oov, and only negative polarity can be obtained in terms of charging ability, so there are various limitations in electrophotography. is recieving. However, the current situation is that the film formation rate is slow, making it difficult to mass-produce and making it expensive.

[Purpose of the invention]

Therefore, an object of the present invention is to provide a functionally separated electrophotographic photoreceptor that has durability equivalent to that of a conventional a-St photoreceptor, has excellent positive charging ability, and has excellent sensitivity. There is something to do.

Another object of the present invention is to relate to an electrophotographic photoreceptor that is excellent in mass productivity and economical efficiency by improving the film formation rate during the production of the photoreceptor.

That is, according to the present invention, periodic table II
A carrier injection blocking layer mainly composed of amorphous silicon containing a group Ia element, a carrier transport layer mainly composed of amorphous silicon, a carrier generation layer and surface protection layer mainly composed of amorphous silicon carbide:! ! Provided is an electrophotographic photoreceptor that can be charged to a positive polarity and is characterized in that layers are sequentially formed.

The present invention will be explained in detail below.

The electrophotographic photoreceptor of the present invention is a functionally separated laminated photoreceptor having the structure shown in FIG.

According to FIG. 1, the photoreceptor of the present invention has carrier injection blocking N (2) and carrier transporting II (3a) on a conductive substrate (1).
), a carrier generation layer (3b) and a surface protection layer (4) are sequentially provided, and a carrier injection blocking layer (2) is formed.
) is provided to prevent carrier injection from the conductive substrate (1) to the carrier transport layer (3a), and the surface protective layer (4) improves the durability and environmental resistance of the photoreceptor. It is established for the purpose of

Taking the photoreceptor having the structure shown in FIG. 1 as an example, and explaining its electrophotographic characteristics based on FIGS. (See figure (a)). Next, when exposure is performed, carrier generation 71 (
In 3a), electrons and holes are generated, the electrons are neutralized with the positive charge on the surface of the photoreceptor, and the holes migrate through the transport layer and are injected to the substrate side and grounded, and the overall charge of the exposed area becomes zero. . (Figure 3 (
b)).

According to the present invention, among the above-mentioned layer configurations, amorphous silicon containing an element of group Ⅰa of the periodic table is used as the carrier injection blocking layer (2), and amorphous silicon (hereinafter referred to as a- It is important to use amorphous carbide (hereinafter abbreviated as a-SiC) as carrier generation N (3b).

The carrier injection blocking layer (2) itself needs to have a high resistance, and needs to have a rectifying effect depending on the charged polarity. In the positively chargeable photoreceptor of the present invention, a group IIIa element of the periodic table is added to the carrier injection blocking layer to increase the resistance and form a P-type semiconductor.

The a-Si in the carrier injection blocking layer is doped with I+ or a halogen element for the purpose of terminating dangling bonds, and the amount thereof is in the range of 5 to 50 atoms 2, particularly 10 to 40 atoms χ, based on the total amount. added.

On the other hand, the Group IIIa element of the periodic table that is added is B.
, AI, Ga, and In, and B is preferable. These are 0.1 to 110,000p in the carrier injection blocking layer.
It is desirable to contain p, especially in the range of 0.5 to 11,000 pp.

In addition, the adhesion to the conductive substrate (1) can be improved by particularly including oxygen in the carrier injection blocking layer in a range of .

a-3t in the carrier transport layer is expressed by the following formula (1)% formula%
(1) In the formula, A is H or a halogen element 0.05≦X≦0.5, especially 0.1≦X≦0.4
The one represented by is preferable. Note that this carrier transport layer also contains the above-mentioned group IIIa element of the periodic table at 110
000 pp, in particular up to 11 000 pp. By adding this Group IIIa element of the periodic table, the carrier transport layer is made intrinsic and the carrier mobility in the carrier transport layer can be increased, thereby improving the surface potential and sensitivity and reducing the residual potential. can do.

Specifically, a-5iC used in the carrier generation layer has the following formula (2) % formula % (2) In the formula, 8 is H or a halogen element 0.01 ≦Y ≦0.9 Particularly, 0.05≦y ≦
0.50.05 ≦Z≦0.5 In particular, 0.1 ≦z
It is expressed as ≦0.4.

In the carrier generation layer, the periodic table IIIa mentioned above is also used.
group elements to 110,000 pp or less, especially 0.5 to 110
By containing in the range of 00 pp, the carrier generation layer becomes a p-type semiconductor, which improves the spectral sensitivity to light wavelengths in the near-infrared region and improves the positive charging ability.

According to the present invention, the group IIIa element of the periodic table added to the carrier generation layer, the carrier transport layer, and the carrier injection blocking layer produces the effects described above in each layer, but at the same time, due to its characteristics as a semiconductor, the energy band is It has the effect of shifting to a type.

Therefore, when adding Group IIIa elements of the periodic table to the carrier injection blocking layer, carrier transport layer, and carrier generation layer, the amount of addition in each layer is 81. B2. When B3 is used, it is important to satisfy the relationship Bl>82>83. If this relationship is not satisfied, an energy barrier is formed at the interface between each layer during carrier movement, making it difficult to inject carriers.

In addition, various materials can be used for the surface protective layer as long as they themselves have insulating properties, high corrosion resistance, and high hardness characteristics, such as organic materials such as polyimide resin, S
iO□+ S iO+ A 1 z Oz + S I
C+ Si 3N g, amorphous carbon can be used.

The layer thicknesses of these four layers mentioned above are determined so as to sufficiently fulfill their respective functions, and in particular, the carrier transport layer is set to be larger than the carrier generation layer, and if the carrier transport layer is thin, it is difficult to maintain charge. The capacity decreases and excellent charging ability cannot be obtained. Specifically, the carrier injection blocking layer is 0.1
The carrier transport layer has a thickness of 10 to 10 μm, the carrier generation layer has a thickness of 0.1 to 10 μm, and the surface protection layer has a thickness of 0.1 μm.
It is desirable to set the thickness to 1 to 10 μm.

According to the method for producing a photoreceptor of the present invention, an inorganic photoreceptor can be produced by a glow discharge decomposition method, an ion blating method,
Thin film forming techniques such as reactive sputtering, vacuum evaporation, and CVD can be used. For example, glow discharge decomposition is preferable when forming the carrier generation layer as described above in the photoreceptor of the present invention. Therefore, to explain in more detail the manufacturing method using the glow discharge decomposition method, the reaction gases used are 5itlt, 5izH6, Si*Ils.
Si-containing gases such as Cl1a, , CJt, Czilz
-C-containing gas such as CJb, CJs, Hz+ if desired
He, Ne, Ar, etc. can be used as a carrier gas, and a gas containing an element of group 1IIa of the periodic table is further contained.

The gas containing Group IIIa elements of the periodic table used is Bl6. BF:+, AI(CHz)3IGa(CH3)
zIIn(CH3)1. Examples include Ga(C11:l):1, and among these, BzHh is preferred in terms of handling and film formation speed.

These gases are adjusted as appropriate depending on the formation of each layer. First, when forming the carrier injection blocking layer, Si-containing gas and 10-b to 1 mol χ, especially 10-S to 0.1
Film formation is performed using a gas containing elements of group 11Ia of the periodic table at a ratio of molar χ. Film formation is performed using a Si-containing gas when forming a carrier transport layer, and using a Si-containing gas and a C-containing gas when forming a carrier generation layer. Note that when forming the carrier generation layer, the film formation rate can be improved by using czn□ gas as the C-containing gas. Especially (Ct
Ht gas:Si-containing gas) composition ratio is 0.05:1 to 3
:1 is desirable.

Note that it is desirable to further add the above-mentioned carrier gas to these reaction gas compositions from the viewpoint of stabilizing the film quality. Further, if desired, when forming the carrier transport layer and the carrier generation layer, it is desirable to add B-containing gas in the same range as when forming the carrier injection blocking layer. In addition, when adding the Group IIIa element of the Periodic Table to each layer, the Group IIIa element of the Periodic Table at the time of forming each layer should be added so that the amount of addition in each layer is in the relationship Bl>BZ>83 as described above. It is necessary to adjust the proportion of gas containing.

Next, a capacitively coupled glow discharge decomposition device used in an embodiment of the present invention will be explained with reference to FIG.

The gas containing Group IIIa elements of the periodic table is B2H.
An example will be given using 6 gases.

In the diagram, 1st, 2nd, 3rd, and 4th tanks (6) (7)
(8) and (9) each contain SiH4+ C2H2, 8g
+16 <B2]16 is diluted to 38 ppm in Ilz gas. ), H2 gas is sealed, and H2 is also used as a carrier gas. These gases are controlled by the corresponding first, second, third, and fourth regulating valves (10) (11)
(12) is released by releasing (13),
The flow rate is the mass flow controller (14') (15
) (16) is restricted by (17) and sent to the main pipe (18).

Note that (19) is a stop valve.

The gas flowing through the main pipe (18) passes through the reaction tube (2).
A capacitively coupled discharge electrode (21) is installed inside this reaction tube, and the electric power applied to this is 50W to 3-3, but the frequency is IMHz.
Inside the reaction tube (20), which has a suitable frequency of 0 to 10 MHz, there is a cylindrical conductive substrate for film formation (2) made of aluminum.
2) is placed on a sample holder (23), this holder (23) is rotated by a motor (24), and the substrate (22) is heated appropriately. from about 50 to 400°C, preferably about 150°C
It is uniformly heated to a temperature of 300°C to 300°C.

Furthermore, the inside of the reaction tube (20) is coated with an a-5i membrane or an a-5i membrane.
A high degree of vacuum B (discharge voltage 0.1 to 2
Rotary pump (゜OTorr) is required.
25) and a diffusion pump (26).

In the glow discharge decomposition device configured as above,
For example, in forming an a-5iC film doped with B, the first. Second. Third. Fourth regulating valve (lO) (
11) (12) Release (13) and move to 1st. Second. Third. 5il14 gas, Czlh gas, B, H, gas and ■2 gas are released from the fourth tank (6) (7) (8) (9), respectively, and the amount of these releases is determined by the mass flow controller (10) (11) ( 12) The reaction tube (2) is regulated by (13) and passes through the main bump (18).
0), and the inside of the reaction tube (20) is in a vacuum state of 0°1 to 2.0 Torr, and the substrate temperature is 50°C.
At a temperature of 400°C to 400°C, a high frequency power of 50 W to 3 with a frequency of 1 to 10 MH2 is applied to the capacitive discharge electrode (21), and a glow discharge occurs, the gas decomposes, and a boron-containing a-5iC film is formed. Formed on a substrate at high speed.

In the layer structure of the photoreceptor according to the present invention, when an organic material is used, it can be formed by any well-known means, and specifically, a polymer material or an organic pigment,
It can be provided by a dipping method, a doctor blade method, etc. using a coating liquid in which an organic dye or the like is dissolved or dispersed in a volatile solvent.

〔Example〕

Hereinafter, the present invention will be explained by examples.

(Manufacturing Example 1 of Photoreceptor) An aluminum drum for a substrate finished to a mirror surface using an ultra-precision lathe using a diamond cutting tool was cleaned by ultrasonic cleaning using an organic solvent, cleaning with Fuji gas, and then drying. It was installed in the reaction tube (20) of the capacitively coupled glow discharge decomposition apparatus shown in FIG.

Then, the first tank (6) was filled with 5iHn gas, the second tank (7) was filled with CzHz gas, and the third tank (8) was filled with B111.
Hz gas was installed in the fourth tank (9), and the reaction gas was flowed at the flow rate shown in Table 1 to form a carrier injection blocking layer on the conductive substrate as a-5i:tl:B:0:N, a-5t:H (X #0.2) as a carrier transport layer, a-3iC:H (Y #0.25, Z as a carrier generation layer)
=0.3) SiC is provided as a surface protective layer, and the thickness is 3
A photosensitive weight of 2.6 μm was obtained.

(Production Example 2) In the same manner as Production Example 1, a reactive gas was introduced at the flow rates shown in Table 2 to form a carrier injection blocking layer of a-5t:H:B:O:N and a-3i:H:B. (X #0.2.B: Approx. 3ppm
), a-5iC:H(Y #0.25
．． A carrier generation layer of Z#0.3) and a surface protection layer of SiC were sequentially provided to obtain a photoreceptor 2 of 33.6 μI.

(Production Example 3) In the same manner as Production Example 1, a reactive gas was introduced at the flow rates shown in Table 3 to form a carrier injection blocking layer of a-Si:H:B:N:O, a-Si:H:B( X#0.2.B: approx. 3 ppm)
carrier transport layer, a-5iC:It:B (Y = 0.
25, Z#0.3, B: approximately 1 ppm) carrier generation layer and SiC surface protection layer were sequentially provided, and the thickness was 29.6 μm.
Obtained Angry Light Body 3.

The three types of photoreceptors obtained were subjected to +5.6 KV corona discharge to increase their surface potential and photosensitivity to monochromatic light (0, 650 nm).
3 μW/cm2), and the residual potential was measured.

The results are shown in Table 4.

As is clear from Table 4, a high surface potential of +700V or more can be obtained, a photosensitivity of 0.50cm"/erg or more,
It exhibited excellent characteristics with a residual potential of 45V or less.

Incidentally, the carrier injection blocking layer (2.5 μm) of the AI-made electrically conductive substrate a-Si:H:B:N:0, a-3i:H:B
(25 μm), a SiC surface protective layer (0.5 μm), and a similar experiment was conducted using a photoreceptor with a surface potential of +410
V, photosensitivity 0, 60cm2/erg, residual potential 20
V and had a low surface potential.

〔Effect of the invention〕

As detailed above, the photoreceptor of the present invention is a functionally separated laminated photoreceptor, and includes a carrier injection blocking layer mainly made of amorphous silicon containing an element of group IIIa of the periodic table on a conductive substrate; By sequentially forming a carrier transport layer mainly composed of amorphous silicon, a carrier generation layer mainly composed of amorphous silicon carbide, and a surface protection layer, it is possible to obtain high positive charging ability, and it is also practical in terms of photosensitivity and residual potential. It is possible to obtain a photoreceptor that has characteristics without any problems and has excellent durability.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the layer structure of a photoreceptor used in an example of the present invention, FIG. 2 is a sectional view showing a general layer structure of a photoreceptor, and FIGS. 3(a) and (b) are FIG. 4, which is a diagram for explaining the electrophotographic characteristics of the present invention, is an explanatory diagram of a capacitively coupled glow discharge decomposition apparatus used in an embodiment of the present invention. 1... Substrate 2... Carrier injection blocking layer 3... Photoconductive layer 3a... Carrier generation layer 3b... Carrier transport layer 4... Surface protective layer Patent applicant (663) Kyocera Corporation Takao Kawamura

Claims (1)

[Scope of Claims] (1) A carrier injection blocking layer mainly made of amorphous silicon containing a Group IIIa element of the periodic table on a conductive substrate, a carrier transport layer mainly made of amorphous silicon, and amorphous silicon carbide. An electrophotographic photoreceptor capable of being charged to a positive polarity, characterized in that a carrier generation layer and a surface protective layer mainly composed of are sequentially formed. (2) The amorphous silicon carbide has the following formula [Si_(_1_-_X_)C_X]_(_1_-_Y
_) A_Y In the formula, A is H or a halogen element 0.01≦x≦0.9 0.05≦y≦0.5 Electrophotographic photosensitive material according to claim 1 body. (3) The carrier transport layer is made of amorphous silicon represented by the following formula Si_(_1_-_Z_)A_Z where A is H or a halogen element 0.05≦z≦0.5. The electrophotographic photoreceptor according to scope 1. (4) The electrophotographic photoreceptor according to claim 1, wherein the carrier transport layer contains an element of group IIIa of the periodic table. (5) The electrophotographic photoreceptor according to claim 4, wherein the carrier generation layer contains an element of group IIIa of the periodic table.