JPH01169462A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To lessen the accumulation of a residual potential at the time of a repeating use, and to improve the stability of the title body for a long period by specifying a photosensitive layer and an intermediate layer in the constitution of the layers, respectively. CONSTITUTION:The photosensitive layer is composed of three layers of As2Se3 layer 2, As2Se3-xTex layer 3 (0.05<=x<0.3) and As2Se3-yTey layer 4 (0.3<=y<=0.8) in this order, observing from a supporting body 1. And an intermediate layer 5 formed on the As2Se3-yTey layer 4 is composed of SiO or a silicone resin comprising 55-88wt.% of silicon and oxygen atoms, 10-30wt.% of carbon atom, 1-10wt.% of hydrogen atom and 1-10wt.% of nitrogen atom in the composition of the layer after curing the coated film. Thus, as the photosensitive body has the excellent electrifiability and the less accumulation of the residual potential, maintaining the high sensitivity to a degree capable of corresponding to a LD ray source, and has a protective layer dispersed fine particles therein, the photosensitive body having a remarkably small abrasion and the high durability is obtd.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an electrophotographic photoreceptor, particularly a semiconductor laser (
It is used in photoreceptors for copiers and printers that use LD as a light source.

[Prior art] Conventionally, a 5e-As layer and an AS25es layer were sequentially deposited on a conductive support.
-* Photoreceptor provided with Te layer (0.05≦X≦2.5) (JP-A-57-24948, JP-A-57-172851)
) is known, but those with a high Te concentration have high sensitivity but low charging potential and are not practical as LD photoreceptors. Furthermore, when the Te concentration is increased to a level compatible with LD, the repetitive residual potential becomes too large to be ignored.

As other photoreceptors, a 5e-As layer and a 5e-Te-As layer (Te: 4
0-47vt%), 5e-As layer, Se or 5e-A
Photoreceptor with S layer (see JP-A-55-186648)
, or a Se layer, 5e-Te on a conductive support in this order
(T e : 50vt%) and a photoreceptor (see Japanese Patent Application Laid-Open No. 58-49949) in which a Se layer is formed is known.
Both photoreceptors have insufficient mechanical durability.

Although it has sufficient charging ability, the residual potential increases with repeated use because it is sandwiched between layers with a narrow band gap. It has a short lifespan because it is unstable to heat.
There are problems like this.

[Objective] The present invention solves the above-mentioned problems of the prior art, and achieves 1)! I
2) High long-term stability; 3) High band abrasion resistance, maintaining the same image quality as the initial image for a long period of time.

4) The object is to provide a photoreceptor for LD that does not easily cause abnormal images even in a high humidity environment.

[Structure] The structure of the present invention for achieving the above object is an electrophotographic photoreceptor in which a conductive support, a photosensitive layer, an intermediate layer, and a protective layer are sequentially laminated. This is an electrophotographic photoreceptor having a photosensitive layer and an intermediate layer.

The configuration of the present invention will be specifically explained with reference to FIG.
As2*ez layer 2, As25el on conductive support l
-, Te, layer 3, As2*Se, -, Te, layer 4, intermediate layer 5, and protective layer 6.

Each component will be explained below in order.

1. Conductive support Although almost any conductive material can be used, Al material is generally used due to its workability, mechanical properties, electrical properties, etc. In particular, the manganese-based A1 alloy specified in JIS 3003 has good processability, relatively good electron injection from the support side to the photosensitive layer, so it has good electrophotographic properties, and the photosensitive layer composed of Se-based It is suitable for

The surface finish of the support is 2000 or higher, preferably 40
A processing method using a grindstone of No. 00 or higher is preferable for obtaining high-quality images.

11. The As2Se three-layer As25es material has high sensitivity and is therefore used for photoreceptors in medium- to high-speed copying machines. However, it has low sensitivity to wavelengths of 780n- or more, so semiconductor lasers (LDs)
) is not used in digital copiers, printers, etc. that use a light source.

The As2Se3 photosensitive layer has much better crystallization resistance than Se or 5eTe, so it is suitable for use as a charge transport layer (referred to as CTL), and is essential for maintaining stable images for a long period of time. . In particular, when forming the third to sixth layers, since the layers are formed by heating to 100 to 130°C, it is necessary to have high crystallization resistance.

Since the relative dielectric constant of the As2Se3 layer is 11 to 13, which is twice as large as that of the Se layer, it is necessary to make it relatively thick in order to obtain charging ability. Usually, it is used in a range of 50 to 70μ, but a range of 40 to 100μ is considered to be within the practical range.

III, As2 Set-w Tea When a photoreceptor is used repeatedly, particular problems are charge fatigue, a decrease in surface potential caused by optical fatigue, and an increase in residual potential. Although it is possible to partially compensate for the decrease in surface potential by controlling the corona discharge current, it is impossible to compensate for the increase in residual potential. In the case of a two-layer structure consisting of a charge transport layer and a charge generation layer (referred to as CGL), since the Te concentration of CGL is as large as 1O to 25vt%, CTL and CGL
A barrier layer that prevents charge injection is formed at the interface, making it easier for holes to be trapped, and this becomes a major factor in the accumulation of residual potential. Therefore, in order to solve this problem, As2Se3
It is desirable that the photosensitive layer closer to the layer has a lower Te concentration, and the Te concentration increases as the layer gets closer to the surface.

In the present invention, the CGL has a two-layer structure, and the first layer of the CGL is made of As2 S e3-x Ten. As5Se
In order to alloy with the ternary system of 1Te, it is necessary to have high structural stability, so A s 2 S e 3-x T
e x, and by changing the value of X, the optical bandwidth is changed.

The value of X is the third layer of As2Se and the second layer of CGL A s 2
Since it is desirable to determine S e i-y T e in balance with the layers, As2Se3-*Te in the first layer
If the X value of w is in the range of 0.05 or more and less than 0.3, the second
It achieves the purpose in terms of balance with the layers.

The thicker the photosensitive layer is, the more holes are trapped in the layer, which becomes another factor in increasing the residual potential. Therefore, it is desirable that the photosensitive layer be as thin as possible, and should be in the range of 0.5 μm to 10 μm, preferably 10 μm. A thickness of ~5μ intestine is sufficient.

TV, As2Se3-, Te.

Since this layer must have sensitivity to the LD light source of 780-820 ns, the bandwidth must be narrower than the first layer of the CGL. The optical bandwidth from 780 nm to 820 na+ is 1.59 to 1.51 (3V).

FIG. 2 shows the relationship between the value of y and the optical bandwidth (Egopt).

From FIG. 2, the value of y corresponding to 1.59 cv is approximately 0.3, and the value of y corresponding to 1.51 ev is approximately 0.5. From this, even if we estimate variations in manufacturing conditions, etc., if the value of y is in the range of 0.3 to 0.8, 780 to 820 nl
It can be applied to LDs with wavelengths of Although a value of y of 0.8 or more is sufficient for practical use, adding more than necessary not only increases the residual potential but also causes structural instability and shortens life.

As with the -CGL layer, if the photosensitive layer is too thick, it may cause residual charging, and if it is too thin, the required sensitivity cannot be obtained. Therefore, in the case of the present invention, sufficient characteristics can be obtained in the range of 3 to 7 μm, but if it is in the range of 1 to 10 μm,
This is a practical area. The sensitivity is approximately 250v- at 780ns.
If it is cI2/μJ or more, it is sufficiently practical.

(2) Intermediate layer It is essential to provide the photosensitive layer of the present invention with an intermediate layer that improves charging ability. The properties required of the intermediate layer are: (1) It must have enough barrier properties to hold the charge necessary for copying for a certain period of time by applying a corona charge, and it must have no residual potential caused by the intermediate layer. to have.

(2) Most of the carriers (electrons in the S e-A s layer), which are generated by exposure to light after charging and have a polarity opposite to the charge on the inner surface of the carriers, are not trapped near the interface between the photosensitive layer and the intermediate layer and are ignited after exposure. is injected into the intermediate layer in a short period of time until charging,
Furthermore, it must have the property of neutralizing and disappearing surface charges.

(3) Electrically and optically uniform, with high transmittance. For example, the optical bandgap must be 2 Oev or more.

(4) Good adhesion to the photosensitive layer.

(5) There are no structural defects that would trap charges in the intermediate layer.

(6) Characteristics should be stable over a long period of time.

(7) Characteristics should not become unstable due to environmental changes.

(8) It can be manufactured relatively easily.

Materials studied in the past include organic materials such as silyl isocyanate, organometallic compounds, alone or in mixtures with silane coupling agents, a-3iCsa-S iN, a-BN,
Inorganic materials such as a-C are relatively easy to use intermediate layer materials. However, it is not possible to satisfy all of the above matters, and each has its own problems.

In particular, organic materials have poor moisture resistance, and inorganic materials are expensive to manufacture and difficult to adjust manufacturing conditions.

Therefore, we investigated materials other than these, and it was confirmed that the specific silicone resin shown in Habuki is particularly excellent as an intermediate layer, and almost satisfies the above eight items.

Specifically, after the coating film is cured, this silicone resin has a) a silicon and oxygen content of 55 to 88 vt%, a) a carbon content of lO to 30 B%, c) a hydrogen content of 1 to 1 Ovt%, and b) a hydrogen content of 1 to 1 Ovt%. Nitrogen content 1vQ
It is a silicone resin in the range of 1-10 vt%.

This silicone resin is made into a solution with an appropriate viscosity using a solvent such as globin, and the number of
It is used by applying in the range of 0 to several μ■, but the appropriate amount is 30
Range of 0 to 1μ, particularly preferably 1500 to 300
It is best to apply and use within the range of 0 people. If the intermediate layer becomes thick, it will cause image blurring at high humidity, and if it is too thin, it will cause image defects such as white spots.

SiO is a preferable material other than the silicone resin. SiO is formed into a film by resistance heating vacuum evaporation method or sputtering method, but the film thickness is 250 to 200 mm.
Good characteristics can be obtained when used within a range of about 0.

Figure 3 shows the rectification characteristics of samples coated with these materials.

(2) is a sample with no overcoat layer, (2) is a sample when approximately 1200 people were coated with the silicone resin, and (2) is a sample where approximately 400 A of SiO was coated.

■■ shows forward rectification characteristics when e is applied to the At support side, while ■ and ■ show forward rectification characteristics when Φ is applied to the Al support side, and Φ charges are applied to the surface layer side. It can be seen that by adding this, the injection of holes into the photosensitive layer can be well suppressed. This is silicone resin SiO As2Se3-x.
This is interpreted to be due to the formation of a barrier layer that injects Φ charges by coating it on the Te layer.If it is thin, there will be pinholes, and if it is thick, the characteristics of the film itself will be affected. It is desirable to do so.

(2) Protective layer The protective layer is essential for improving the mechanical durability of the photosensitive layer. The requirements for a protective layer are: (1) High mechanical durability.

(2) Do not retain residual images any longer than necessary.

(3) Be substantially transparent in the emission wavelength range of the LD. Specifically, there is no practical problem if the transmittance is 80% or more in a wavelength range of 700 ns or more.

(4) No deterioration due to external factors such as electric fields, light, and ozone.

(5) Moisture resistance and extremely low moisture absorption.

(6) Good surface smoothness.

(7) Toner filming should not occur.

(8) Must have solvent resistance.

etc.

Materials that satisfy these conditions include ester crosslinking,
A layer of urethane cross-linked styrene-MMA resin with 40-70% of 5n02 added as a resistance control agent is formed on the intermediate layer.
By forming a film of 10 μm, it is possible to obtain durability of 200,000 to 400,000 sheets. For example, S, nO in the above resin
When 60% of 2 is added, the transmittance is 480 at 5 μm.
It shows 75% in ns and 80% in 640 nm or more, while the resolution shows 30 lines/SS or more, and there is no optical problem at all.

In addition, as an inorganic material, a-8i Cs
There is a method of coating a-C%a-BN or the like.

The present invention will be specifically explained below based on Examples.

Example I SUS circular ice tube boat for As2Se3 (1 boat)
, As2 Se5-m Ten boat (second boat)
and A s 2S e 3-, T e , boat (
A vacuum evaporator equipped with a third boat was used.

Thoroughly degreased 10051 x 60w x O,5
An Al plate of t (am) is used as a support, and As2 is placed on the first boat.
135 gr of Se3 material, As2 Se in the second boat
2. s Teo, z to 15gr, then A to the third boat
s2 Se2. a Teo, 6 was added to lOgr. Then, the temperature of the support for the As2Se three layers was set at 180°C.
2 S e 3-x T e x layer support temperature 15
The temperature was set at 0°C, and the deposition boat was energized to form As2Se with a thickness of about 55 μm.
Three layers were formed. Next, energize the second boat and As2S
e2. g Teo, 2 for 3 μs, and then electricity was applied to the third boat to vaporize 2 μl of As2562.4.Tea, 6.

A silicone resin diluted to about 2% liquid with ligroin (A
After applying 2-441) by dipping method, 120
It was heat-dried at ℃ for 1 hour to obtain an intermediate layer of about 1800 people.

Furthermore, the ratio of styrene-MMA-2HEMA is 2:5:3
Sn was added to the prototype urethane cross-linked styrene-MMA resin.
O2 fine particles (58 w1% of Mitsubishi Metals) were added, and toluene, cellosolve acetate, and MIBK were added at 3:
A solvent mixed at a ratio of 4:3 was added and dispersed for 120 hours using a ball mill method. Then, fatty acid polyisocyanate (Sumidur WHT) was added and further dispersed, and then coated by a dipping method and dried by heating at 13° C. for 30 minutes to form a protective layer of about 5 μm thick.

The electrophotographic characteristics of the photoreceptor obtained by such a manufacturing method were measured. The results are shown in Table 1.

Example 2 Materials to be put into the third boat A S 2 S e 2.
A coated photoreceptor was prepared using the same materials and manufacturing method as in Example 1, except that 2.Tea and s were used, and the electrophotographic characteristics were measured.

Example 3 135 gr of As2Se3 was placed in the first boat, and As2Se28. Te0. , 15g of Ag3Se2.2Teo,a was put into the third boat of 7.5grs, the support temperature during steaming was set at 135°C, and the first boat was energized to deposit 55μ of As2/Se3 layer. . Next, power is applied to the second boat and then the third boat, and As-5e
-Te layer each 1.5μ+a.

3.0μ of pus was deposited.

The photoreceptor obtained in this way was set in another vacuum evaporation device, and the tantalum boat was filled with 5iO (Furuuchi Kagaku 99.
99%) of 530+wg and energized for about 1 minute
A 0.times.0.times.SiO vapor deposited film was produced.

Furthermore, a protective layer was formed with a thickness of 5 μm using the same materials and manufacturing method as in Example 1.
Created.

Table 1 shows the results of measuring the electrophotographic properties of the photoreceptor obtained by such a manufacturing method.

Comparative example 1 SUS circular ice cube boat for As2Sez)
, Ag35e3-I Tea boat (second boat) and As25ei-y Te boat (third boat)
Thoroughly degreased using a vacuum evaporation device equipped with 10
0 cross x 60w
As2 Se2. on the second boat. s Teu, isg z
r, and As2 S62.4Tea on the third boat, b
10g of was added.

Then, the temperature of the support for the two As2Se layers was set at 180℃As25
The support temperature of the e3-*Te layer was set to 150°C, and the temperature of all three deposition boats was set to 420°C. 1×lO
At a vacuum level below Torr, first, the first boat was energized to form an As2Se2 layer of about 55 μ-.Then, the second boat was energized to form As2Se2., ITea, 2.
for 3 μs, and then energized the third boat and As2Se2,4
Teo, 6 was deposited to a thickness of 2 μm.

Table 1 shows the electrophotographic properties of the photoreceptor obtained by such a manufacturing method.

Comparative Example 2 135 gr of As2Ses was put into the first boat, 20 gr of Ag3 S e2.2 Teo,a was put into the second boat,
The support temperature during vaporization of As2Se three layers was 180”c, As
The support temperature during -3e-Te deposition was set at 130''c.

First, the first boat was energized at a vacuum level of less than I x 10' Torr to form an As2Se3 layer with a thickness of about 55μ.

Next, electricity was applied to the second boat to form an As-9e-Te layer with a thickness of 4 μm.

On the thus prepared photoreceptor, using the same materials and manufacturing method as in Example 1, a 1800 silicone resin layer and a 5n02 dispersed urethane crosslinked styrene-MMA resin layer were formed to a thickness of about 5 μm.

Table 1 shows the electrophotographic properties of the photoreceptor obtained by such a manufacturing method.

The electrical characteristics in Table 1 were measured using a Kawaguchi Electric Vapor Analyzer 5P-428 except for S 780, and using a Ricoh spectral sensitivity measurement device to measure S 711.
10 was measured.

Table 1 vs: Surface potential after 20 minutes of +6.5 kV application DD: Vs
Dark potential retention rate V++ after 20 seconds: Sensitivity when irradiating light source on 2g56 However, 100 Vol from +800 Volt
t At light attenuation S tan: Sensitivity at 100 Volt light attenuation from 1 loOVol at 7110 ns light irradiation ΔVs: Amount of change in surface potential equivalent to 500 sheets of continuous charging/exposure (in this case, it shows a decrease) Δv praise: Δvs Similarly, the amount of change in residual potential that occurs after exposure (in this case, it shows an increase) Excellent performance and low accumulation of residual potential.

Furthermore, since it has a protective layer in which fine particles are dispersed, it is an excellent photoreceptor with extremely low wear and durability of more than 300,000 A4 size copies.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the structure of the photoreceptor of the present invention, and FIG.
FIG. 3 is a graph showing the relationship between the composition and optical bandwidth of a -9e-Te photoreceptor. FIG. 3 is a graph showing the relationship between the composition of the photoreceptor and rectification characteristics. , l... Conductive support, 2... As2Se3 layer, 3
”, A s 2 S e 3-x T ex layer, 4-
As2 Se, -, Te, layer, 5... intermediate layer, 6...
・Protective layer.

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor in which a conductive support, a photosensitive layer, an intermediate layer, and a protective layer are sequentially laminated, wherein each of the photosensitive layer and the intermediate layer has the following structure. . a) The structure of the photosensitive layer consists of As_2Se_3 layer, As_2Se_3_-_1Te_x layer, (0.05≦x≦0.3) As_2Se_3_-_yTe_y layer, (0.3≦y≦0.8) in order from the support side. b) The intermediate layer formed on the As_2Se_3_-_yTe_y layer is SiO or a silicone resin having the following composition after the coating film is cured. Silicon and oxygen 55-88 wt% Carbon 10-30 wt% Hydrogen 1-10 wt% Nitrogen 1-10 wt%