JPH07271074A - Production of electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To obtain a charge transfer layer excellent in heat resistance, increased in carrier mobility and improved in charge injection efficiency at the time of laminating a photoconductive layer on the charge transfer layer by forming a specified polymer layer and then heat-treating the layer in an oxygen- contg. atmosphere. CONSTITUTION:This electrophotographic photoreceptor having the laminate of a photoconductive layer to generate a carrier movable by light excitation and a charge transfer layer into which the carrier is efficiently injected and which is movable effectively from the injection side to the opposite side is produced. In this case, a polymer layer consisting essentially of the structure contg. p-phenylene and any of S, Se and Te in the principal chain and shown by the formula is formed, and then the charge transfer layer is heat-treated in an oxygen-contg. atmosphere. As a result, a thermal decomposition reaction, a thermal polymerization reaction or oxygen doping is induced in the polymmer layer, and a charge transfer layer having excellent heat resistance and large carrier mobility with respect to the photoconductive layer such as a-SiiH having a small ionization potential and into which a charge from the photoconductive layer is efficiently injected is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electrophotographic photosensitive member used in electrophotographic copying machines, optical printers and the like.

[0002]

2. Description of the Related Art As a photoconductor for an electrophotographic photosensitive member, amorphous silicon (hereinafter referred to as a-Si: 10 to 40 atm%) containing hydrogen as a modifier for reducing the localized density of states is used.
H) is noted and used because of its high photosensitivity, pollution-free property, and high hardness.

However, there are still many problems to be solved in the above electrophotographic photosensitive member composed of a-Si: H.

For example, the first problem is a-Si: H.
Has a large dielectric constant of about 11 (OPC: about 3, Se: about 6) as compared with other photoconductor materials such as organic photo-semiconductors (hereinafter referred to as OPC) or Se, and therefore has a large capacitance, A very large charging current is required when charging the surface.

Further, in order to obtain a practical surface potential (up to 400 V), the charge density of the surface charge is high, and a large amount of light energy is required to photo-eliminate this charge, so that the actual photosensitivity is sufficiently high. It can not be said.

A second problem is silane (SiH
_In the plasma CVD method using a gas (referred to as ₄ ) as a raw material gas, the deposition rate is as low as 10 μm / H or less, and the SiH ₄ gas is also expensive, so it is difficult to reduce the manufacturing cost.

The third problem is that the film thickness is 30 μm.
Often used below m, the charging electric field strength is also 30V / μm
From the level, the practical surface potential is 5 compared to 800V of the Se photoconductor.
Since it is used at a potential as low as 00 V or less, there is a problem that a usual two-component developer cannot obtain a copy having a sufficient image density.

[0008]

As a means for solving such problems, Japanese Patent Laid-Open Publication No. 54-143645 discloses a function-separated type photoreceptor using an organic semiconductor material.

When formed and used on a photoconductive layer using this organic semiconductor material, although the charging potential can be improved by decreasing the dielectric constant, the hardness of the organic semiconductor material is small, so that S
The characteristics of the amorphous photoconductive film containing i as a high-hardness long-life photoreceptor cannot be utilized. Further, in order to form a good quality a-Si: H film at a temperature of 150 ° C. or higher on a conventional organic semiconductor, a good electrophotographic photoreceptor cannot be obtained because of poor heat resistance. Alternatively, it has been proposed to heat-treat polyacrylonitrile (PAN) having heat resistance,
Since sufficient carrier mobility and carrier lifetime have not been obtained, the residual potential is high and the sensitivity cannot be said to be sufficient.

[0010]

A photoconductive layer that generates movable carriers by photoexcitation and a charge transfer layer that is capable of effectively injecting the carriers and effectively moving from the injection surface to the opposite surface are provided. In the method for producing an electrophotographic photosensitive member to be laminated, oxygen is added to the charge transfer layer after forming a polymer layer mainly containing the following structure containing p-phenylene and any of S, Se and Te in the main chain. By performing the heat treatment in an atmosphere containing the above, a charge transfer layer having high heat resistance, high carrier mobility, and high charge injection efficiency from the photoconductive layer can be obtained.

[0011]

[Chemical 2]

[0012]

[Function] An atmosphere containing oxygen for 0.1 to 15 hours at 150 to 450 ° C. after formation of a polymer layer mainly containing the above structure containing p-phenylene and any of S, Se and Te in the main chain. By performing heat treatment in the polymer layer, a thermal decomposition reaction, a thermal polymerization reaction, or oxygen doping is induced in the polymer layer, and a-S
It is possible to obtain a charge transfer layer having a high heat resistance, a large carrier mobility, and a high charge injection efficiency from the photoconductive layer with respect to a photoconductive layer having a small ionization potential such as i: H.
In particular, some structural changes reduce the optical bandgap and improve the injection efficiency.

Further, the dielectric constant is as small as 3 to 3.5, which improves the surface potential and reduces the charging current.

Due to the above synergistic effect, an electrophotographic photosensitive member having a small residual potential, a high sensitivity and a large charging potential can be obtained.

[0015]

EXAMPLE FIG. 1 is a schematic sectional view showing an example of a basic electrophotographic photosensitive member according to the present invention.

The electrophotographic photoreceptor shown in FIG. 1 comprises a support 1 as an electrophotographic photoreceptor, a charge transfer layer comprising a polymer layer containing p-phenylene and any of S, Se and Te in the main chain. 2 and a photoconductive layer 3, said photoconductive layer 3 having a free surface 4 on the one hand.

In the present invention, the photoconductive layer has high hardness.
As a photoconductive layer using an amorphous layer containing silicon
Is a-Si (: H: X), a-Si_1-yC_y(: H:
X) (0 <y <1), a-Si_1-yO_y(: H: X) (0 <
y <1), a-Si_1-yN_y(: H: X) (0 <y <
1), a-Si_1-zGe_z(: H: X) (0 <z <1),
a- (Si_1-zGe_z)_1-yN _y(: H: X) (0 <y, z
<1), a- (Si_1-zGe_z)_1-yC_y(: H: X) (0
<Y, z <1) or a- (Si_1-zGe_z)_1-yO_y
(: H: X) (0 <y, z <1) where X is a halogen element
A single element layer or a laminate of these is used. Also, y
It can also be used when is continuously changed.

The film thickness at this time is 5 to 50 for the charge transfer layer.
The thickness of the photoconductive layer may be 0.5 to 10 μm, and preferably 1 to 5 μm.

In the present invention, in order to further improve the electrophotographic characteristics, the support 1 and the charge transfer layer 2 in FIG.
A barrier layer for effectively blocking the carriers injected from the support 1 to the charge transfer layer 2 may be provided between and.

As a material for forming the barrier layer, Al is used.
₂ O ₃ , BaO, BaO ₂ , BeO, Bi ₂ O ₃ , CaO,
CeO ₂ , Ce ₂ O ₃ , La ₂ O ₃ , Dy ₂ O ₃ , Lu ₂ O ₃ ,
Cr ₂ O ₃ , CuO, Cu ₂ O, FeO, PbO, Mg
O, SrO, Ta ₂ O ₃ , ThO ₂ , ZrO ₂ , HfO ₂ ,
Metal oxides such as TiO ₂ , SiO ₂ , GeO ₂ , SiO, GeO or TiN, AlN, SnN, NbN, Ta
Metal nitride such as N, GaN, or WC, SnC, Si
Metal carbide such as C and TiC or Si ₂ N ₃ , GeC and G
An insulating material such as eN, BC, BN, or a heat-resistant organic compound such as polyimide, polyamide-imide, or PAN is used.

A surface coating layer is formed on the free surface 4 in FIG. 1 in order to improve the cleaning property, the wear resistance or the corona resistance. Suitable materials for the surface coating layer include Si _x O _1-x , Si _x C _1-x , and Si _x N
_1-x , Ge _x N _1-x , Ge _x O _1-x , Ge _x C _1-x , B
Examples include _x C _1-x , B _x N _1-x , Al _x N _1-x (0 <x <1), and inorganic substances such as layers containing hydrogen or halogen therein.

A-S, a photoconductive layer containing silicon
To create i (: H: X), use SiH _Four, Si₂H₆, Si₃
H₈ , SiF_Four, SiCl_Four, SiHF₃, SiH₂F₂,
SiH₃F, SiHCl₃, SiH₂Cl₂, SiH₃Cl
Plasma CVD method using a source gas of Si atoms such as
Targeting polycrystalline silicon or Ar and hydrogen (sa
Rani F₂Or Cl₂May be mixed) in a mixed gas
A reactive sputtering method is used. In addition, a-Si_1-yC_y
(: H: X) (0 <y <1), a-Si_1-yO_y(: H:
X) (0 <y <1), a-Si_1-yN_y(: H: X) (0 <
For the production of y <1), CH is used as a carbon source._Four, C
₂H₆, C₃H₈, C_FourH_Ten, C₂H_Four, C₃H₆, C ₆H₆Etc.
Hydrocarbon, CH₃F, CH₃Cl, CH₃I, C₂H_FiveC
l, C₂H_FiveAllyl halides such as Br, CClF₃, C
F_Four, CHF₃, C₂F₆, C₃F₈CFCs such as CFCs₆H
_6-mF_m(M = 1 to 6) C atom source gas such as benzene
For mixed or reactive sputtering, a spatter such as Ar is used.
Used as a mixture with Tagus. Also, as an oxygen source, O₂,
CO, CO₂, NO, NO₂Etc., and N as the nitrogen source
₂, NH₃, NO and the like are mixed and used.

Ge is added to a-Si (: H: X).
If you do GeH_Four, Ge₂H₆, Ge₃H₈, GeF_Four, G
eCl_Four, GeHF₃, GeH₂F₂, GeH₃F, GeH
Cl ₃, GeH₂Cl₂, GeH₃A gas such as Cl is added to the above Si
It may be formed by plasma CVD method by mixing with source gas.
I can do it.

Further, in the present invention, the above-mentioned a-S
i _1-y C _y (: H: X) (0 <y <1), a-Si _1-y O _y
(: H: X) (0 <y <1), a-Si _1-y N _y (: H:
X) (0 <y <1) or a film in which Ge is added thereto can be doped with impurities to control conductivity and obtain desired electrophotographic characteristics. Examples of p-type impurities that impart p-type conductivity include B, Al, Ga, In, and the like, which belong to Group IIIb of the periodic table, and are preferably B and A.
n, P, As, and Sb belonging to Group V b of the periodic table are used as n-type impurities that give n-type conductivity.
Etc., and P and As are preferably used.

Further, as a method of adding these impurities
In the case of p-type impurities, B₂H₆, B _FourH_Ten, B_FiveH₉, B_Five
H₁₁, BF₃, BCl₃, BBr₃AlCl₃, (CH₃)₃
Al, (C₂H_Five)₃Al, (i-C_FourH₉)₃Al, (CH
₃)₃Ga, (C₂H_Five)₃Ga, InCl₃, (C₂H_Five)₃
If In is an n-type impurity, N₂, NH₃, NO, N
₂O, NO₂, PH₃, P₂H_Four, PH_FourI, PF₃, PC
l₃, PCl_Five, PBr₃, PBr_Five, PI₃, AsH₃, A
sF₃, AsCl₃, AsBr₃, SbH₃, SbF₃, S
bF_Five, SbCl₃, SbCl_FiveGas such as
H for these gases₂Gas diluted with He, He, Ar
In the Zuma CVD method, it is mixed with the raw material gas when each film is formed.
In the reactive sputtering method, Ar or
H₂Or F₂, Cl₂It may be used as a mixture. Less than
An example will be described.

Example 1 A surface-polished aluminum drum was coated with poly-p-phenylene sulfide (hereinafter referred to as PPS).
Described above) is hot-pressed in an inert gas at ˜300 ° C. to ˜20 μm. It goes without saying that a releasing agent is applied to the jig during pressing in order to melt the PPS. After the formation, the surface is slightly polished to a mirror surface to form a charge transfer layer. The PPS in this state is a slightly yellowish and nearly transparent film. PPS has the structure X:
The polymer was S, n = 10 to 30.

[0027]

[Chemical 3]

This drum is further heated in air to 150 to 25
Heat treatment is performed at 0 ° C. for 0.1 to 5 hours. The drum thus obtained became brownish and had an optical band gap of ˜2.4 eV.

This was subjected to capacitive coupling plasma CVD having a cylindrical discharge electrode having a length of 45 cm and an inner diameter of 16 cmφ.
After being placed in the apparatus and evacuating the reaction vessel to 5 × 10 ⁻⁶ Torr or less, the aluminum drum was heated to 150 to 200 ° C. SiH ₄ 50 to 150 sccm, C ₂ H ₂ 2
-10 sccm, B ₂ H ₆ to SiH ₄ 5-100p
pm, pressure 0.2 to 1 Torr, high frequency power 100 to 2
₁ to 5 a-Si _1-x C _x : H layers as photoconductive layers at 50 W
and μm formed, followed by 20 to the C ₂ H ₂ with respect to SiH ₄
Increased to 50 sccm and a-Si _1-x as a surface coating layer
A C _x : H layer was formed in an amount of 0.05 to 0.5 μm to obtain an electrophotographic photosensitive member. The a-Si _{1- x} C _x : H layer of the photoconductive layer had an optical bandgap of 1.7 to 1.9 eV at this time, and this photosensitive band was mounted on an optical printer using an LED of 670 nm as a light source. Then, clear printing was confirmed at a surface potential of +500 to 800 V when positively charged.

The residual potential of this drum is +100 to 200.
It was V. Further, if a- (Si _1-z Ge _z ) _1-x C _x : H in which Ge is added to the a-Si _1-x C _x : H layer is used, the sensitivity is further improved.

Further, although the sulfurized polymer layer is used as the charge transfer layer, the same characteristics can be obtained with a chalcogenized polymer of Se or Te.

As a material for replacing the a-Si _1-x C _x : H layer as a surface coating layer, 0.1-0.5 μm a-Ge
_{A 1-x} C _x : H (0 <x <1) layer was formed by a plasma CVD method and mounted in an optical printer in the same manner. As a result, the electrophotographic photosensitive member of this structure was excellent in heat resistance and moisture resistance, It was confirmed that the plate has printing durability.

Further, by adding TCNQ as an electron acceptor in an amount of 0.05 to 0.1 wt% to the PPS polymer layer, the residual potential was further reduced, and an electrophotographic photosensitive member as small as 50 to 90 V could be obtained.

[0034]

According to the present invention, when a photoconductive layer that generates movable carriers by photoexcitation is laminated on a charge transfer layer, the charge transfer layer has p-phenylene, S, Se and After forming a polymer layer containing any of Te, by performing heat treatment in an atmosphere containing oxygen,
It is possible to form a charge transfer layer which is excellent in heat resistance, has a large carrier mobility, and has a reduced optical bandgap, and which has a high charge injection efficiency from the photoconductive layer.

Due to the above synergistic effect, the residual potential is small,
An electrophotographic photoreceptor having high sensitivity and a large charging potential can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of an electrophotographic photosensitive member according to an embodiment of the present invention.

[Explanation of symbols]

 1 Support 2 Charge Transfer Layer 3 Photoconductive Layer 4 Free Surface

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Koji Akiyama 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Masanori Watanabe 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] 1. An electrophotographic apparatus comprising a photoconductive layer for generating movable carriers by photoexcitation and a charge transfer layer for effectively injecting the carriers and capable of effectively moving from the injection surface to the opposite surface. In the method for producing a photoconductor, in the atmosphere containing oxygen, after forming a polymer layer containing the following structure containing p-phenylene and any of S, Se, and Te in the main chain of the charge transfer layer as a main component. A method for manufacturing an electrophotographic photosensitive member, which includes a step of performing heat treatment. [Chemical 1] 2. The method for producing an electrophotographic photosensitive member according to claim 1, wherein an electron acceptor is added to the polymer layer. 3. The method for producing an electrophotographic photosensitive member according to claim 1, further comprising the step of forming an amorphous layer in which the photoconductive layer contains a modifier that reduces the localized density of states. 4. The method for producing an electrophotographic photosensitive member according to claim 3, wherein the photoconductive layer contains at least either hydrogen or a halogen element. 5. The method for producing an electrophotographic photosensitive member according to claim 1, further comprising the step of forming a surface coating layer on the free surface.