JPS6314163A - Electrophotographic sensitive body and its production - Google Patents

Abstract

PURPOSE:To prevent the scumming of an image by specifying the doping of oxygen and tungsten to an electric charge transfer layer. CONSTITUTION:The oxide of the tungsten is simultaneously evaporated to dope the oxygen at 50X10<-6>-200X10<-6>atom% and the tungsten at 15X10<-6>-110X10<-6>atom% into the electric charge transfer layer at the time of evaporating selenium or selenium alloy and forming the charge transfer layer on a conductive substrate 1 in a vacuum vessel, The cylindrical conductive substrate 1 consisting of an aluminum alloy is disposed rotatably in an arrow direction in the vacuum vessel and a vapor deposition boat 2 in which a selenium-tellurium alloy 4 is packed is installed below said substrate. A flash vapor deposition boat 5 is juxtaposed in proximity to the boat 2 and the boat 5 is heated by direct energization thereof. The accumulation of a residual poten tial is thereby decreased and the good image which is free from the scumming is stably obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to an electrophotographic photoreceptor using amorphous selenium or an amorphous selenium alloy as a photoconductive material, and a method for manufacturing the same.

[Prior art and its problems]

The performance of an electrophotographic photoreceptor (hereinafter also simply referred to as a photoreceptor) used as an image forming member of an electrophotographic device is that it has a high ability to accept electric charge (can be charged to a sufficiently high required potential in a dark place, and , when it is dark, there is little charge leakage and the charge decay rate is low, and the charged potential can be maintained; when light is irradiated, the surface charge is rapidly discharged, the charged potential is attenuated, and the residual potential is sufficient. It is required that fatigue is negligible when charging and exposure are repeated continuously, and that increase in dark decay and accumulation of residual potential are small.

In order to satisfy such demands, functionally separated photoreceptors have recently been attracting attention. This photoreceptor is composed of a layered carrier transport layer that mainly contributes to charging in the dark and chimal transport during exposure, and a carrier generation layer that mainly contributes to carrier generation during exposure. By pursuing the optimal design of each separated layer according to its function, a photoreceptor with better characteristics than a single-layer photoreceptor in which one layer has these functions can be obtained.

A functionally separated type photoreceptor using a selenium-based material as a photoconductive material has also been developed, for example, a carrier transport layer made of amorphous selenium or an amorphous selenium-tellurium alloy and an amorphous Photoreceptors are known that have a carrier generation layer made of a crystalline selenium-tellurium alloy or an amorphous selenium-tellurium-arsenic alloy. However, when images are continuously and repeatedly formed on such a photoreceptor, residual potential accumulates as shown in Figure 3, resulting in background smudges on the image. A satisfactory photoreceptor with a small amount of

[Purpose of the invention]

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a photoreceptor and a method for manufacturing the same, in which residual potential accumulates less even when images are formed repeatedly, and the image surface is less smeared. do.

[Key points of the invention]

An object of the present invention is to evaporate selenium or a selenium alloy in a vacuum chamber to form a charge transport layer on a conductive substrate, and simultaneously evaporate tungsten oxide to add 50×10 − 6 atomic% ~ 200 × 10-6
atomic%, tungsten from 15 × 10-6 atomic% to 11
This is achieved by doping 0 x 10-6 atomic %.

[Embodiments of the invention]

Examples of the present invention will be described below.

FIG. 1 is an explanatory diagram showing a method of depositing a charge transport layer during the production of a photoreceptor according to the present invention, in which a cylindrical conductive substrate made of an aluminum alloy is placed in a vacuum chamber (not shown). A vapor deposition boat 2 filled with a selenium-tellurium alloy 4 is installed below the vapor deposition boat 1, and a flash vapor deposition boat 5 is arranged in parallel with the vapor deposition boat 2. The flash vapor deposition boat 5 is heated by directly applying electricity to the boat. Pressure inside the vacuum chamber I
With a vacuum of 10-' Torr, the deposition boat 2 is heated to about 300°C by the heater 3 while rotating while maintaining the substrate l at a temperature of 65°C, and a selenium-tellurium alloy containing 5.5% by weight of tellurium is heated. Evaporate 4.

At the same time, the flash vapor deposition boat 5 is energized to lower its temperature to 1.
000°C or above, tungsten oxide 110° fine powder (shown in granular form in the figure for convenience) is supplied little by little, flash evaporated, and the vapor is co-evaporated onto the substrate 1 together with selenium-tellurium vapor to form approximately A charge transport layer having a thickness of 60 μm was formed at a film formation rate of 1 μm/7 minutes. , '10. The amount is 500 p by weight relative to the amount of selenium-tellurium alloy.
pn was supplied. When the content of oxygen and tungsten in the charge transport layer thus formed was examined by activation analysis, it was found that oxygen was doped at 100 x 10-6 atomic % and tungsten was doped at 40 x 10-6 atomic %. Next, a charge generation layer made of an amorphous selenium-tellurium-arsenic alloy and having a thickness of 5 μm was formed on this charge transport layer to prepare a photoreceptor.

Image formation was performed continuously and repeatedly on the photoreceptor of this example, and the residual potential of the photoreceptor at that time was examined.

The results are shown in FIG. As can be seen in Figure 2, the residual potential is very small, about 10 V at first, and the increase thereafter is extremely small.Furthermore, it saturates at about 20 V within the first few repetitions, and the residual potential remains until 250 repetitions. No accumulation is observed. Further, no staining on the image was observed.

For comparison, a photoreceptor was prepared in the same manner as in the example except that only the flash vapor deposition of step 110 was not performed in forming the charge transport layer. When I checked the potential, the initial value was 30V, which was large, and after 50 times it increased to 80V and 100V.
The amount increased to 100 sq. after 250 times, and a significant accumulation of approximately 130 sq. 110 in this example. It turns out that co-evaporation of is extremely effective.

The saturation value of the residual potential when images are formed repeatedly is dependent on the content of oxygen during charge transport. If the oxygen content is low, the saturation value will be large; if the oxygen content is high, the saturation value will be small. At this time, it is important that tungsten coexists.By coexisting tungsten, oxygen is doped uniformly and stably into amorphous selenium or amorphous selenium-tellurium alloy, resulting in a photoreceptor with stable characteristics. is obtained. The amount of oxygen during charge transport is approximately 50 XIQ-6 atomic%, and the amount of tungsten is 1
When the concentration is about 5XlO-6 atomic%, the saturation value of the residual potential is 8
If it is about 0.0 cm, the saturation value becomes too large and staining on the image surface becomes a practical problem. Also, the amount of oxygen is 20
0 x 10-6 atomic%, tungsten content is 110
When it becomes about ×10-6 atomic%, the saturation value is about IOV and no staining on the image is observed, but on the other hand, the dark attenuation becomes large and the content of these becomes even higher (as the amount of charge decreases). As a result, the attenuation of charging becomes large, which becomes a practical problem.

The reason why the accumulation of residual potential in the photoreceptor decreases when an appropriate amount of oxygen and tungsten are doped into the charge transport layer is not yet fully understood, but doping with oxygen causes trapping of holes. This is presumed to be because the level becomes shallow and the density of hole traps is also reduced.

In this embodiment, 0° was used as the doping material, but wO□ or -4011 can be used equally effectively.

〔Effect of the invention〕

According to the present invention, when selenium or selenium alloy is evaporated in a vacuum chamber to form a charge transport layer on a conductive substrate, tungsten oxide is simultaneously evaporated to provide 50×10 − of oxygen in the charge generation layer. 6 atom% ~ 200 x 10-
6 atomic%, tungsten 15X10-6 atomic%~ll
Doped with 0XIO-6 atomic percent. The electrophotographic photoreceptor manufactured in this manner has little accumulation of residual potential even after continuous and repeated image formation, and is capable of stably providing good images without background smudge.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of one embodiment of vapor deposition of a charge transport layer of the present invention, FIG. 2 is a diagram showing the accumulation of residual potential in a photoreceptor of one embodiment, and FIG. 3 is a diagram of a conventional photoreceptor. FIG. 3 is a diagram showing the accumulation of residual potential. 1 conductive substrate, 2 vapor deposition boat, 3-1. Heater, 4- Selenium alloy, 5- Fluffy double vapor deposition boat, 6
-Tungsten oxide. Figure 1 gz

Claims (1)

[Scope of Claims] 1) An electrophotographic photoreceptor having a charge transport layer made of amorphous selenium or an amorphous selenium alloy and a charge generation layer made of an amorphous selenium alloy on a conductive substrate, comprising: Oxygen in the charge transport layer is 50×10^-^6 atomic% to 200×1
0^-^6 atomic%, tungsten is 15 x 10^-^6
An electrophotographic photoreceptor characterized in that it is doped in an amount of 110×10^-^6 atomic %. 2) When selenium or selenium-tellurium alloy is evaporated from an evaporation source in a vacuum chamber to form a charge transport layer on a conductive substrate, tungsten oxide is simultaneously evaporated to introduce oxygen into the charge transport layer. 50×10^-^6 atomic%~20
0x10^-^6 atomic%, 15x10^ of tungsten
A method for producing an electrophotographic photoreceptor, characterized in that it is doped with -6 atomic % to 110 x 10 6 atomic %. 3) A method for manufacturing an electrophotographic photoreceptor according to claim 2, wherein the tungsten oxide is WO_2. 4) A method for manufacturing an electrophotographic photoreceptor according to claim 2, wherein the tungsten oxide is WO_3. 5) A method for manufacturing an electrophotographic photoreceptor according to claim 2, wherein the tungsten oxide is W_4O_1_1.