JPS6348558A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the titled body having stabilized characteristics, without increasing dark decay of charge potential even at a high temperature by using a non-crystalline selenium alloy which is doped with tin (Sn) as a carrier transfer layer. CONSTITUTION:The carrier transfer layer 2 is formed by vacuum-depositing the selenium alloy doped with Sn on a conductive substrate 1. Thus, when the selenium alloy is doped with Sn, fractionation of the component elements of the alloy is controlled in the deposition, thereby making a composition ratio of the component elements uniform in the direction of film thickness of the formed carrier transfer layer 2. As a result, the dark decay of the charge potential, even at the high temperature, does not increase, and the stable selenium type titled body having less tendency for generating variance of characteristics is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to an electrophotographic photoreceptor having a photosensitive layer made of a selenium-based photoconductive material.

[Prior art and its problems]

Examples of selenium-based photoconductive materials used in electrophotographic photoreceptors include pure selenium (Se) and selenium-tellurium (Se-
Te) alloys, selenium-arsenic (Se-, As) alloys, selenium-tellurium-arsenic (Se-Te-As) alloys in various composition ratios, and in addition to these, oxygen (0) and bismuth (Bi).

Some products are doped with antimony (Sb), halogen, etc. as impurities, and have the functions required as photoreceptors.
Naroton is made from one of these materials depending on its properties.
Photoreceptors with a photosensitive layer made of - or photoreceptors with a photosensitive layer formed by laminating several types of materials have been commercialized.

A photosensitive layer made of such a selenium-based photoconductive material;
Usually, a film is formed on a substrate by a vacuum evaporation method. In this case, a problem when using alloy materials is that fractional distillation occurs due to differences in the vapor pressures of the component elements. Therefore, a photosensitive layer formed by vapor-depositing an alloy material has a profile in which the composition ratio of the component elements in the film thickness direction is not uniform, which may affect the photoelectric properties of the photoreceptor. Become. For example, Se has a much higher vapor pressure than Te and is easier to evaporate. Therefore, when a 5e-Te alloy is evaporated in vacuum and formed into a film on a substrate, fractional distillation of Se and Te occurs, and the initially formed portion of the evaporated film contains more Se than the alloy component ratio and a large amount of Te. After that, as the film formation progresses, Se decreases and Te increases, resulting in a composition ratio with less Se and more Te on the surface of the deposited film.

In this way, when focusing on the Te concentration, the deposited film has a concentration profile that changes from a low concentration to a high concentration in the film thickness direction from the substrate side toward the surface.

Such a difference in Te concentration increases as the deposited film becomes thicker, and becomes a practical problem. For example, when forming a single-layer light layer with a 5e-Te alloy vapor deposited film, or
When using an e-alloy vapor deposited film as a carrier transport layer and a carrier generation layer thereon to form a photosensitive layer, 5e-Te of a predetermined composition ratio is used to obtain the required charging performance as a photoreceptor by 14%.
The alloy is vacuum deposited to a film thickness of 50 μm to 60 μm,
In order to achieve this, a large amount of 5e-Te alloy must be deposited over a long period of time, so there is a portion where the Te concentration deviates from the target residue and becomes very large due to fractional distillation of Sa and Te. As a result, more thermally excited carriers are generated. Therefore, especially at high temperatures, the dark attenuation of the -3 light single charge potential increases, and when used in an electrophotographic device, the density of the output power decreases at high temperatures.

Moreover, this concentration profile is not always constant;
There is also the problem that it fluctuates due to variations in the protrusion conditions such as the manufacturing loft of the alloy material and the deposition lot, making it difficult to fully control.

[Purpose of the invention]

The present invention has been made in view of the above points, and it is an object of the present invention to provide a stable selenium-based electrophotographic photoreceptor that does not increase the dark decay of charged potential even at high temperatures and has less rough characteristics. shall be.

[Key points of the invention]

An object of the present invention is to provide an electrophotographic photoreceptor comprising a carrier transport layer and a grin generation layer formed by vacuum evaporation and made of an amorphous selenium alloy, the carrier transport layer being doped with tin (Sr+). This is achieved by making the base metal amorphous.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing the layer structure of an embodiment of the photoreceptor of the present invention. In FIG. 1, 1 is a conductive substrate made of, for example, an aluminum alloy, 2 is 5e-Te,
This is a carrier transport layer (CTL) in which 5e-As or 5e-Te-AS alloy doped with Sn to a predetermined maximum is vacuum-deposited to a thickness of about 60 μm; 3 is 5e-Te, 5 is
e-As or 5e-Te-As alloy with a film thickness of several μm
This is a carrier generation layer (CC, L) vacuum-deposited on. C
There are various combinations of alloy materials used for TL and CGL, some of which are shown in Table 1. The numerical values before Te and As in Table 1 indicate their respective weights in the alloy, and for Sn, they indicate weight ppm.

Table 1: Specific Examples - Conductive groups are listed in Article 1, Article 12.
A 0 mm 2 aluminum alloy cylinder was used, and the second combination of CTL and CCL in Table 1 was formed on its surface.

That is, 5e15.5Te/1000Sn was vacuum-deposited to form a CTL, and Se/30Te15As was vacuum-deposited thereon to form a CGL-bound photoconductor. For comparison, Se without Sn doping was used as CTL material Ho4.
Using 5e15.5Te, which is a /Te alloy, a photoreceptor was prepared as a comparative example using the same structure as that of the above-mentioned example.

, - T e , 13 degree profiles were measured for these photoreceptors at EP~1A. The results are shown in FIG. 2 for the example and in FIG. 3 for the comparative example. 2nd゜3rd
In FIG. 2, the vertical axis shows the intensity of characteristic X-rays of Te, and the horizontal axis shows the position of the photosensitive layer starting from the interface with the substrate. The horizontal axis indicates the interface and surface of the photosensitive layer with arrows. Te in CTL
The concentration gradient difference in the X-ray intensity is 3Qcps in the case of Figure 2,
In the case of FIG. 3, it is +30 cps, and it can be seen that in the case of the example in which the CTL is doped with Sn, the fractional distillation of Se and Te during vacuum evaporation is sufficiently suppressed.

Next, these photoreceptors were subjected to charging potential (1) at an ambient temperature of 25°C. Measure the charged potential retention rate and residual potential after 5 seconds in the dark, take the value at that time as 100% of the original value, and calculate the charged potential, charged potential retention rate, and residual potential when the ambient temperature is changed. It was called the rate of change. The results are shown in FIG. 4 for the example and in FIG. 5 for the comparative example.

In the example shown in FIG. 4, when the ambient temperature is 25°C, the charged potential (5) is 846 V, and the charged potential retention rate is 92.1 V.
%, residual potential ■ was 12V. These values are 10
0% and the ambient temperature is 50? 'We investigated the fluctuations in these five characteristics by varying the temperature. For example, when the ambient temperature is 45°C, band 7, retention rate, and residual potential are each 2.
FIG. 4 shows that the change was 9096.34% of the straightness at 5° C., which was 13% of the straightness. On the same note, regarding the comparative example, for example, in open air, @ degree is from 25℃ to 45℃.
Obi when it changes to ℃? 1st place, retention rate is 25℃ each
When! Direct 842. 39. g% or 88%, 17
%, the residual potential is 0 (0%) at 12V.
To! ; This can be seen from Figure 5. When comparing FIG. 4 with FIGS. 5 and 5, the major difference is the variation in the retention rate of the charged potential due to temperature change, and this variation is significantly smaller in FIG. In other words, the dark attenuation of the charged potential of the photoreceptor does not increase much even if the charge voltage becomes high. This was obtained by doping Sr into the selenium alloy material forming the CTL.

Furthermore, the photosensitive material was prepared according to the actual example! , TLO book and 10 photoreceptors prepared according to the comparative example) were subjected to continuous charging and exposure misting 500 times, and the fluctuations in the charged potential were investigated. The results are shown in Table 2. In Table 2, is the initial charging potential. . is the 500th charge potential 1 Δ■
is the value obtained by subtracting Vsoo from ■I to avoid a decrease in charging potential.

From Table 2, it is clear that the Example group had less decrease in charging potential and more stable characteristics.

The amount of Sn doped into CTL is 100 ffippm ~
Range 1 of 5000 ppm by weight is preferred. 100 heavy ff
If the amount is less than ippm, the effect of doping Sn will not occur. Furthermore, the effect of doping with Sn at several thousand mffippm is saturated, and the effect does not increase even if the amount of doping is further increased.

Moreover, as the amount of Sn doped increases, the amount remaining in the evaporation source during vacuum deposition increases and becomes difficult to remove.Therefore, the amount of Sr+ doped is 50
00 weight'1. It is preferable to suppress it to less than 7 ppm.
),.

〔Effect of the invention〕

According to the present invention, the carrier transport layer is made of tin (Sl' l) is formed of a doped amorphous i-len alloy. In this way, the dry layer is formed by vacuum deposition of a Sn-doped selenium alloy.
If Sn is doped, fractionation of constituent elements of the alloy during vapor deposition can be suppressed, and the formed chiaria transport
The composition ratio of the component elements in each direction becomes almost uniform, and as a result, the dark decay of the charged potential increases even at high temperatures.
A stable selenium-based electrophotographic photoreceptor with less variation in properties is used, and when used in an electrophotographic device, it produces output images with excellent image quality without a decrease of 5 degrees in density. This makes it possible to obtain output images (which can be output continuously without any problem).

[Brief explanation of drawings]

Fig. 1 is a schematic concave view of the photoconductor O-home 1', 7jC of the present invention, and Fig. 2 is one embodiment of the great invention, photosensitive to ylI, and the concentration of tellurium in the film thickness direction of 1. Figure 3 is a diagram showing the tellurium concentration profile in the film thickness direction of the photosensitive layer of a conventional example, and Figure 4 shows temperature fluctuations in the characteristics of the photoreceptor of an example of Zero-Hatsu. FIG. 5 is a diagram showing temperature fluctuations in the characteristics of a conventional photoreceptor. 1 Conductive substrate, 2 Ki+'JA transport layer, 3 Upper layer
1 Figure pmG56055504S4035302520 f
s10! ;0Figure 2μfnc560ss 5045403530,>
5 20 Is IOS Otsuta 2 Figure Atmosphere 1 degree °' Figure 4

Claims (1)

[Scope of Claims] 1) An electrophotographic photoreceptor comprising a carrier transport layer and a carrier generation layer made of an amorphous selenium alloy formed by vacuum deposition on a conductive substrate, wherein the carrier transport layer is An electrophotographic photoreceptor comprising an amorphous selenium alloy doped with tin (Sn). 2) In the photoreceptor according to claim 1, the carrier transport layer contains tin (Sn) in an amount of 100 ppm to 5.0 ppm by weight.
An electrophotographic photoreceptor comprising an amorphous selenium alloy doped within a range of 0.00 ppm by weight.