JPS61269162A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To increase a sensitivity of the titled body in a long wavelength range, and to improve a heat stability and a durability and also a residual potential of the titled body by laminating a surface layer contg. at least a selenium and an arsenic directly or through an electric charge generating layer composed of a selenide alloy on the electric charge holding layer contg. the selenium, the arsenic and a halogen. CONSTITUTION:The electric charge holding layer 2 composed of the selenium.tellurium.arsenic.chlorine alloy, the electric charge generating layer 3 composed of a selenium.telluriom alloy and the surface layer 4 composed of a selenium.arsenic alloy are formed on an electroconductive substrate 1 composed of an aluminium. Preferably, the additional amount of the tellurium is 2-10wt%, the additional amount of the arsenic is 0.2-5wt% and the additional amount of the chlorine is 5-200ppm, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of an electrophotographic photoreceptor.
・Anki Senki left. Photoreceptors traditionally used for electrophotography include zinc oxide, OPC, and selenium, but of these, selenium is the most heavily used, with its high resolution, durability, and electrical properties. It has excellent stability compared to other materials. However, selenium has an effective sensitivity only in the short wavelength range of about 550 nm, excluding the long wavelength sensitivity range due to crystalline selenium, and even a slight temperature rise inside the device will cause the surface of the photoreceptor to crystallize, making it unusable. It has drawbacks such as being lost. For this reason, it has been proposed to eliminate these drawbacks by using various additives.

Among these, tellurium sensitization is the most commonly used. The addition of tellurium increases sensitivity and also contributes to some extent to suppress crystallization. However, in order to provide sufficient sensitivity in the entire visible light range, the amount of tellurium added must be large, making the transition to crystallization more likely.

Furthermore, electrical properties become unstable, such as a decrease in potential holding rate and an increase in fatigue, which requires careful attention in practice. On the other hand, when sensitization is carried out by adding arsenic, sensitivity and heat resistance are simultaneously improved, making it possible to provide a photoreceptor with high sensitivity and excellent thermal stability. However, the selenium-arsenic photoreceptor has drawbacks in fatigue characteristics and aging characteristics, and its effective sensitivity range is limited to 700 nm.

Furthermore, adding arsenic at a high concentration poses many manufacturing difficulties. The present invention eliminates the above-mentioned drawbacks, and provides an electrophotographic photoreceptor which has increased sensitivity in the long wavelength range, improved thermal stability and durability, and improved electrical properties, particularly residual potential. Figures 1 (al and b) are block diagrams of an electrophotographic photoreceptor according to an embodiment of the present invention. In the figures, 1 is a conductive support made of aluminum or the like. 2 is selenium tellurium 1,
It is an arsenic-chlorine alloy and forms the charge retention layer of the photoreceptor. 3 is a selenium-tellurium alloy, which forms the charge generation layer of the photoreceptor. Further, 4 is a selenium-arsenic alloy, which forms the surface layer of the photoreceptor. Furthermore, an intermediate layer is provided between the conductive support 1 and the charge retention layer 2 to improve electrical or mechanical properties. may be provided as necessary, and other usual additions, changes, modifications, etc. may be made. Figure 1 (
In a), a surface layer 4 is directly laminated on the charge retention layer 2, and this surface layer 4 forms a high-sensitivity layer and has a sensitizing effect. Of course, the surface layer 4 has a charge generation function when irradiated with light or the like. In FIG. 1(a), it is necessary to add excessive amounts of tellurium, arsenic, etc. to achieve high sensitivity, which may result in a decrease in electrical resistance and make it difficult to maintain the surface potential. FIG. 1(b) shows a method in which a charge generating layer 13 made of a selenide alloy containing a high concentration of tellurium is separately formed between the surface layer 4 and the charge retention layer 2.
This is to improve the photoreceptor having the configuration a) and also to make it more sensitive in the long wavelength region. The charge retention layer 2 described above,
The amount of impurities added to the selenide alloy of the charge generation layer 3 and the surface layer 4 plays an important role in determining the electrical or mechanical properties of the photoreceptor. FIG. 2 shows the influence of the amount of each element added in the selenium-tellurium-arsenic-chlorine alloy in the charge retention layer 2 of the present invention on the electrophotographic properties, particularly on the residual potential and the variation in surface potential during repeated use. That is, the solid line shows the relationship with the loading amount of tellurium, and its increase tends to decrease the residual potential and increase the surface potential drop during repeated use. , 7, and the chain line shows the relationship with the amount of arsenic added, and the effect of its addition tends to further increase the influence of tellurium. Furthermore, the dotted line shows the relationship with the amount of chlorine added, and it can be seen that the effect is greater than the former two. Therefore, it is possible to find an improvement point for appropriately suppressing the increase in the surface potential drop and reducing the residual potential. Furthermore, considering heat resistance, etc., the amount of tellurium added was determined by experiment to be 2 to 1.
It was found that 0% by weight, an amount of arsenic added of 0.2 to 5% by weight, and an amount of chlorine added of 5 to 200 ppm are preferable. In addition,
In place of chlorine in the charge retention layer 2, other halogen elements, iodine, bromine, fluorine, etc. may be used. The preferred amount of tellurium added to the selenium-tellurium alloy of the charge generating layer 3 in FIG. 1(b) was 20 to 50% by weight and the thickness was 0.1 to 1 μm. Also, arsenic is added to the selenium-arsenic alloy with surface WI4 for sensitivity and heat resistance! 1~20% heavy background, thickness 1~
Preferably, the thickness is 10 μm. In addition, in this specification, expressions such as selenium/tellurium φ arsenic/chlorine alloy, selenium/arsenic alloy, selenium/tellurium alloy, etc. are used depending on the main component that determines the characteristics and cannot be removed or removed. A trace amount of unnecessary impurities may be included. Next, the present invention will be explained with reference to experimental examples. A heating medium 13 to 5 is placed inside the vacuum evaporation mechanism.
-C@! 1! 'Wlヮka 3□ months, 54□□□
1 was installed, and three evaporation sources were installed below it.

The first evaporation source is a selenium-tellurium-arsenic-chlorine alloy (tellurium, arsenic, chlorine each 5% by weight, 1% by weight, 150pp).
m), and the second evaporation source is a selenium-tellurium alloy (
20% by weight of tellurium) was added. Further, a selenium-arsenic alloy (7% by weight of arsenic) was added to the third evaporation source. Moreover, a shutter that can be opened and closed arbitrarily was provided above each evaporation source. A 120 x 300 I aluminum drum with a rough surface finish was subjected to appropriate surface treatment and fixed to a rotating support in a vacuum evaporator tank, and the drum was kept at 80° C. and evacuated to start vapor deposition. The photosensitive layers were laminated by operating each evaporation source in the order of heating→evaporation→opening→close→end of heating. The laminated thickness and time required for each evaporation source are as follows: The first evaporation source laminates 55 μm in 30 minutes, the second evaporation source laminates 1 μm in 3 minutes,
The third evaporation source stacked 21) m in 2 minutes. This photosensitive drum was placed in a sample bag, and evaporation was further performed without using a third evaporation source to prepare sample 2. Furthermore, Sample 3 having the same specifications as Sample 1 was deposited using a selenium-arsenic-chlorine alloy (2% by weight of arsenic, 00pp of chlorine) as the first evaporation source.

For comparison, as a sample not according to the present invention, a selenium-tellurium alloy (tellurium 5% by weight) was placed in the first evaporation source, and sample 4 having the same specifications as sample 1 was evaporated. Sample 1, sample 3
Sample 4 and Sample 4 formed a three-layer structure, and were found to have sufficiently high spectral sensitivity in the long wavelength region and stable characteristics. Next, the temperature inside the device was set to 45% using the actual machine.
An image test was conducted at 0.degree. C., and the durability results shown in Table 1 were obtained.

It was confirmed by observation using mfR steel that the crystallization of Sample 4 in Table 1 reached the surface of the aluminum drum that was the support. This is considered to be because crystallization occurs from the aluminum drum side.

Note that the surfaces of samples 1 to 3 (4 in Figure 1 (a) and (b))
) as a selenium-tellurium-arsenic alloy (tellurium 0.
5 to 6% by weight and 1 to 20% arsenic), good results similar to those shown in Table 1 could be obtained in the durability test.

As described above, the electrophotographic photoreceptor of the present invention increases sensitivity in the long wavelength region, improves thermal stability and durability, and improves residual potential, so it can be used in copiers, printers, etc. This is extremely effective.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are structural diagrams of an electrophotographic photoreceptor according to an embodiment of the present invention, in which l represents a conductive support 2, a charge retention layer, 3 a charge generation layer, and 4 a surface layer. be. FIG. 2 shows an electrical characteristic diagram. Patent applicant Shindengen Kogyo Co., Ltd. Yamanashi Electronics Kogyo Co., Ltd.

Claims (4)

[Claims] (1) An electrophotographic photosensitive material characterized in that a surface layer containing at least selenium and arsenic is laminated on a charge retention layer containing at least selenium, arsenic, and halogen, either directly or via a charge generation layer made of a selenized alloy. body. (2) Tellurium concentration 2-10% by weight, arsenic concentration 0.2-5
The electrophotographic photoreceptor according to claim 1, comprising a charge retention layer containing a chlorine concentration of 5 to 200 ppm by weight. (3) An electrophotographic photoreceptor according to claims (1) and (2), which comprises a charge generation layer containing a tellurium concentration of 10 to 50% by weight. (4) An electrophotographic photoreceptor according to claims (1), (2), and (3), comprising a surface layer containing an arsenic concentration of 1 to 20% by weight.