JPH0623855B2 - Electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of an electrophotographic photoreceptor. Conventionally used so-called electrophotographic photoconductors are zinc oxide type, OPC type, selenium type, etc. Among them, selenium is most importantly used, and its resolution, durability, and electric Both stability and excellent compared to other materials.

However, selenium has an effective sensitivity only up to a short wavelength region up to about 550 nm except for the long wavelength sensitivity region due to crystalline selenium, and the surface of the photoconductor can be crystallized even if the temperature inside the device is slightly increased. It has drawbacks such as disappearance. Therefore, it has been proposed to eliminate these drawbacks by using various additives. The most commonly used of these is tellurium sensitization. The addition of tellurium increases the sensitivity and also contributes slightly to the suppression of crystallization. However, in order to have sufficient sensitivity in the entire visible light range, a large amount of tellurium is added, and the transition to crystallization is more likely to occur. Furthermore, the potential holding ratio decreases, fatigue increases, and other electrical characteristics become unstable, so careful attention is required for practical use.

On the other hand, when arsenic is added to increase the sensitivity, sensitivity and heat resistance are simultaneously improved, so that it is possible to provide a photoreceptor having high sensitivity and excellent thermal stability. However, the selenium / arsenic photoreceptor has drawbacks in fatigue characteristics and aging characteristics, and the effective sensitivity range is up to 700 nm. Further, addition of high concentration of arsenic has many difficulties in manufacturing.

The present invention solves the above-mentioned drawbacks, increases the sensitivity in the long wavelength region, improves thermal stability and durability, and at the same time provides an electrophotographic photoreceptor having improved electrical characteristics, especially residual potential.

FIG. 1A is a configuration diagram of a conventional photoconductor, and FIG. 1B is a configuration diagram of the photoconductor of the present invention. In the figure, 1 is a conductive support made of aluminum or the like. In the case of (b), 2 is a selenium-tellurium-arsenic-halogen alloy and forms the charge retention layer of the photoreceptor. Reference numeral 3 is a selenium-tellurium alloy, which forms the charge generation layer of the photoconductor. Also, 4 is (b)
In the case of, it is a selenium-arsenic alloy and forms the surface layer of the photoreceptor. An intermediate layer for improving electrical or mechanical properties may be provided between the electrically conductive support 1 and the charge retentive layer 2, if necessary, and other usual additions, changes, modifications, etc. may be performed. Is.

In FIG. 1 (a), the surface layer 4 is directly laminated on the two charge retention layers, and the surface layer 4 forms a high sensitivity layer and has a sensitizing effect. Of course, the surface layer 4 has a function of generating electric charges by light irradiation or the like.

In FIG. 1A, it is necessary to excessively add tellurium, arsenic or the like in order to obtain high sensitivity, and as a result, the electric resistance may be lowered and it may be difficult to maintain the surface potential. First
FIG. 2 (b) shows that a charge generation layer 3 made of a selenide alloy containing high-concentration tellurium is separately formed between the surface layer 4 and the charge retention layer 2. Is also improved, and at the same time, high sensitivity is achieved in the long wavelength region. The charge retention layer 2, the charge generation layer 3, and the surface layer 4 described above.
The amount of impurities added to the selenide alloy plays an important role in determining the electrical or mechanical properties of the photoreceptor.

FIG. 2 shows the effect of the addition amount of each element of selenium, tellurium, arsenic, and chlorine alloy in the charge retention layer 2 of the present invention on electrophotographic characteristics, particularly residual potential and surface potential fluctuation during repeated use. That is, the solid line shows the relationship with the addition amount of tellurium, and its increase tends to decrease the residual potential and increase the surface fall potential in repeated use. The chain line shows the relationship with the added amount of arsenic, and the effect of the addition tends to further increase the effect of tellurium. Furthermore, the dotted line shows the relationship with the amount of chlorine added, and it is clear that the effect is greater than the former two. Therefore,
It is possible to find an improvement that reduces the residual potential by appropriately suppressing the increase in the surface drop potential.

Further, taking heat resistance and the like into consideration, it was found by experiments that the addition amount of tellurium is preferably 2 to 5% by weight, the addition amount of arsenic is 0.2 to 5% by weight, and the addition amount of chlorine is 5 to 150 ppm. Instead of chlorine in the charge retention layer 2, other halogen elements such as iodine, bromine and fluorine may be used.

The addition amount of tellurium in the selenium-tellurium alloy of the charge generation layer 3 in FIG. 1B is 10 to 50% by weight, and the thickness is 0.1 to 1 μm.
Was a preferable value. Further, the selenium-arsenic alloy of the surface layer 4 preferably has an arsenic addition amount of 1 to 20% by weight and a thickness of 1 to 10 μm in view of sensitivity and heat resistance.

In the present specification, the expressions such as selenium / tellurium / arsenic / chlorine alloy, selenium / arsenic alloy, and selenium / tellurium alloy are represented by the main components that determine the characteristics, and it is difficult or unnecessary to remove them. A minute amount of impurities may be contained.

Next, the present invention will be described with reference to experimental examples. A drum rotary support whose temperature can be controlled by a warm medium was installed in the vacuum vapor deposition machine tank, and three evaporation sources were installed below it. Selenium-tellurium-arsenic-chlorine alloy (tellurium, arsenic, chlorine 5% by weight, 1% by weight, 150 ppm, respectively) is put in the first evaporation source, and a selenium-tellurium alloy (tellurium 20 is used in the second evaporation source).
% By weight). Further, a selenium-arsenic alloy (arsenic 7% by weight) was added to the third evaporation source. A shutter that can be opened and closed arbitrarily is provided on each evaporation source. A 120φ × 300L aluminum drum having a mirror-finished surface was subjected to an appropriate surface treatment, fixed on a rotary support in a vacuum vapor deposition machine tank, and the drum was kept at 80 ° C. to be evacuated to start vapor deposition.

The photosensitive layers were laminated by operating each evaporation source in the order of heating → vapor deposition → shutter → close → heating end.

The film thickness of each evaporation source and the required time are 55
μm was laminated in 30 minutes, the second evaporation source was laminated in 1 μm in 3 minutes, and the third evaporation source was laminated in 2 μm in 2 minutes. This photosensitive drum is referred to as Sample 1. For comparison, as a sample not according to the present invention, a selenium-tellurium alloy (tellurium 5% by weight) was put in the first evaporation source, and the other sample 2 having the same specifications as the sample 1 was vapor-deposited.

It was found that Sample 1 and Sample 2 have a three-layer structure, and have sufficiently high spectral sensitivity in the long wavelength region and stable characteristics. Then, using the actual machine, increase the internal temperature to 4
An image test was conducted at 5 ° C., and the results as shown in Table 1 were obtained for durability.

It was confirmed by observation with a microscope that the crystallization of Sample 2 reached the surface of the aluminum drum as the support.
It is considered that this is because crystallization occurs from the aluminum drum side. As described above, the electrophotographic photosensitive member of the present invention has an increased sensitivity in the long wavelength region, improved thermal stability and durability, and at the same time improved residual potential, it is extremely effective when used in a printer. It is a thing.

[Brief description of drawings]

FIG. 1A is a configuration diagram of a conventional photoconductor, and FIG. 1B is a configuration diagram of a photoconductor of the present invention. 1 is a conductive support, 2 is a charge retention layer, 3 is a charge generation layer, 4 Is the surface layer. FIG. 2 shows an electrical characteristic diagram.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroaki Sawato Hiroaki Sawato 462 Ozato-cho, Kofu-shi, Yamanashi Yamanashi Electronics Co., Ltd. (72) Kazuhito Dohi 462 Ozato-cho, Kofu-shi, Yamanashi Yamanashi Electronics Co. In-company (72) Inventor Yuichi Murata 10-13 Minamimachi, Hanno-shi, Saitama Shindengen Industrial Co., Ltd. In-house company inspector Yoshio Sugano (56) Reference JP-A-58-100854 (JP, A) JP JP-A-58-5745 (JP, A) JP-A-58-173749 (JP, A) JP-A-57-158845 (JP, A) JP-A-56-149046 (JP, A) JP-A-56-142538 (JP , A) JP-A-57-24946 (JP, A)

Claims (1)

[Claims] 1. A three-layer photoconductor in which a charge retention layer composed of selenium, tellurium, arsenic and halogen, a charge generation layer composed of selenium and tellurium, and a surface layer composed of selenium and arsenic are further stacked thereon. , The charge retention layer has a tellurium concentration of 2 to 5% by weight, the arsenic concentration of 0.2 to 5% by weight, the halogen concentration of 5 to 150 ppm, and the charge generation layer of a tellurium concentration of 10 to 50% by weight. Arsenic concentration is 1 to 20
An electrophotographic photosensitive member having a three-layer structure, wherein the electrophotographic photosensitive member has a weight percent.