JPH073594B2 - Electrophotographic photoconductor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention has a photosensitive layer formed on a conductive substrate, whose main functions are to maintain a charged position in a dark place and to transport a charge during exposure. Consists of a first layer and a second layer formed on the first layer, the main function of which is to generate charges during exposure, and the second layer has an amorphous arsenic selenide (As ₂ Se ₃ ) composition The present invention relates to a photoreceptor for electrophotography, which is made of amorphous selenium / arsenic alloy and whose first layer is made of amorphous selenium / arsenic alloy having a lower arsenic content than the second layer.

[Conventional technology]

Among the performances required for the electrophotographic photoreceptor used as an image forming member of an electrophotographic copying machine, the high sensitivity performance and the original due to the high speed and low power consumption of the electrophotographic copying machine are important. And the blue color reproducibility.

Conventional photoreceptors mainly composed of pure Se or Se-Te alloy have been found to have limitations in such performance.
As seen in 74255, a photoconductor mainly composed of Se-As alloy has been developed. For this material, As ₂ Se _3, which is a stoichiometric bond, is the most stable in terms of its physical properties.
A single-layer type photoconductor using a Se—As alloy material having a composition of ₂ Se _{3 or} close to it has been widely adopted. However, the disadvantage of this material is that it has a relatively large relative permittivity, so that it requires a large power supply load to charge the surface potential required for forming a copied image and a deep carrier trap. The behavior to light is unstable. On the other hand, as already filed by the present applicant in Japanese Patent Application No. 61-96280 (Japanese Patent Application Laid-Open No. 62-241754), amorphous Se-formed on a conductive substrate is used.
The photosensitive layer made of As alloy is separated into the first layer, which has the function of maintaining the charge potential in the dark and transporting the charge during exposure, and the second layer, which has the function of generating charge during exposure. The second layer is formed of amorphous selenium / arsenic alloy having a composition close to that of amorphous As ₂ Se ₃ or, and the first layer is made of amorphous Se- whose arsenic concentration is lower than that of the second layer. It is said that by using an As alloy, a photoconductor that has a single photosensitive layer of amorphous selenium / arsenic alloy having a composition of amorphous As ₂ Se ₃ or close to it has high sensitivity and good color reproducibility. While taking advantage of the advantages, it is possible to improve the charging performance, which is a drawback thereof, and reduce light fatigue, and it is possible to obtain an electrophotographic photoreceptor suitable for a copying machine that operates at high speed and has low power consumption.

[Problems to be solved by the invention]

An object of the present invention is to improve the characteristics of the electrophotographic photoconductor described above, to improve the sensitivity, and to reduce the rise in residual potential.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention provides a first layer in which a photosensitive layer formed on a conductive substrate has a main function of maintaining a charged position in a dark place and transporting a charge at the time of exposure. It is composed of a second layer formed on the surface of the second layer whose main function is to generate electric charges during exposure, and the second layer is amorphous arsenic selenide (As ₂ Se ₃ )
Or consisting of amorphous selenium-arsenic alloy having a composition close to that, the first layer contains halogen, the arsenic content is 30 ~
It shall consist of amorphous selenium-arsenic alloy in the range of 33.5% by weight.

[Action]

Figure 1 shows that As concentration of 30-40
Curve 11 shows the temperature characteristics of the residual potential when 5000 ppm was added to the charge transport layer made of a Se-As alloy by weight, and curve 12 when it was not added. Is effective in suppressing the rise in Also, the addition of halogen improves the sensitivity at the same time.

Further, the second layer is composed of amorphous arsenic selenide (As ₂ Se ₃ ) or an amorphous selenium / arsenic alloy having a composition close to that, and the first layer is made of a non-crystalline material having an arsenic content of 30 to 33.5% by weight. By using crystalline selenium / arsenic alloy, high sensitivity and good color reproducibility can be obtained, and the charging performance change amount can be suppressed.

Example FIG. 2 shows a conceptual layer structure of a photoconductor of an example of the present invention. A tube made of JIS A3003 aluminum alloy having an outer diameter of 120 mm is used as the conductive substrate 1, and the surface is mirror-finished. Degreasing and etching with nitric acid were performed. This base 1
Is mounted on a rotary support shaft that can control the temperature in the vacuum deposition tank,
The chamber was evacuated to a vacuum of 5 × 10 ⁻⁵ Torr, and the first evaporation source for the charge transport layer 2 and the second evaporation source for the charge generation layer 3 arranged below the support shaft were made of Se having a predetermined composition. -Contains As alloy. A predetermined amount of iodine as a halogen is added to the material of the first evaporation source for the charge transport layer. Next, first, the first evaporation source was heated to 440 ° C. to vacuum-deposit the charge transport layer 2 on the substrate 1, and then the evaporation source was similarly heated to vacuum-deposit the charge generation layer 3. The film thickness of each layer was adjusted by the filling amount of the material accommodated in the evaporation source. As an example, the composition of each layer was changed 5
Eight types of photoconductors were produced, including a photoconductor of a single type, a photoconductor having a single layer, a photoconductor having a high As concentration, or a photoconductor containing no halogen as a comparative example. Table 1 shows the composition of those photoreceptors,
The film thickness is shown.

For these photoconductors, the charging performance after pre-exposure with a tungsten lamp light with a color temperature of 3000K at a light amount 100 times the half-attenuated exposure amount of each photoconductor, pre-exposure (light removal) -charge
Amount of change in charging performance when repeating 0 cycles, color temperature 3
Table 2 shows the results of measuring the half-attenuated exposure dose with a tungsten lamp light of 00K and the residual potential at 23 ° C. for some of the photoconductors.

It can be seen from Table 2 that the photoreceptors of Examples have smaller fluctuations in charging performance and smaller half-attenuation exposure amount, that is, higher sensitivity than the case of a single layer, and a charge transport layer in the case of a function-separated photoreceptor. It can be seen that when the As concentration exceeds 33.5%, the charging performance is low, and according to the present invention, the charge transport layer contains iodine, so that the sensitivity is high. Similar results can be obtained by using a halogen element other than iodine.

〔The invention's effect〕

The present invention relates to a charge generation layer composed of amorphous arsenic selenide (As ₂ Se ₃ ) or an amorphous selenium / arsenic alloy having a composition close to that, and an amorphous selenium having an arsenic content of 30 to 33.5% by weight. .By providing a charge transport layer made of arsenic alloy,
By adding halogen to the charge transport layer of the electrophotographic photoreceptor with improved charging performance and reduced light fatigue, it is possible to further improve the sensitivity and reduce the rise in residual potential below room temperature. It was

[Brief description of drawings]

FIG. 1 is a temperature characteristic diagram of residual potential showing the effect of the present invention,
FIG. 2 is a conceptual cross-sectional view of the photoconductor of the embodiment of the present invention. 11: iodine added, 12: iodine not added, 1: conductive substrate, 2: charge transport layer, 3: charge generation layer.

Claims (1)

[Claims] 1. A first layer having a photosensitive layer formed on a conductive substrate, which has a main function of maintaining a charged position in a dark place and transporting charges during exposure, and a first layer formed on the first layer during exposure. The first layer is composed of a second layer whose main function is the generation of electric charges, and the second layer is composed of amorphous arsenic selenide (As ₂ Se ₃ ) or an amorphous selenium-arsenic alloy having a composition close to that of the first layer. Contains halogen, and is composed of an amorphous selenium-arsenic alloy having an arsenic content in the range of 30 to 33.5% by weight.