JPS6032182B2 - Photoreceptor manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a photoreceptor, and more particularly to a method for manufacturing a photoreceptor that is improved to have high sensitivity to relatively long wavelength light.

Electrophotographic technology is expanding into applications such as computer peripherals, facsimile machines, and hard copy plate making machines for microfilm machines.

Generally, in computer peripherals and facsimile machines, images are reproduced using electrical signals representing image information. Therefore, a gas laser whose output is controlled in accordance with the electrical signals is applied to a uniformly charged photoreceptor surface using an optical mirror or the like. is scanned to form a static exposure latent image, after which a desired reproduced image is obtained on recording paper by toner development and transfer.

In order to spectral sensitize the photoreceptor surface and obtain a high-quality reproduced image, attempts have been made to use alloys such as SeTe as the photoreceptor;
When the composition ratio of Te in Te alloy is increased, SeTe
SeT containing a desired amount of Te due to the large vapor pressure difference between
In addition to making it difficult to obtain e-alloys, as the Te concentration increases,
The conductivity of the photoreceptor increases, and the number of localized energy levels of the photoreceptor increases, and by repeating a series of operations such as uniform charging, electrostatic port image formation, development, and transfer, the photoreceptor increases. This leads to fluctuations in the body's exposure sensitivity and a decrease in the electrical charge level,
It has been difficult to obtain high-quality reconstructed images.

The present invention has been made in view of the above, and an object of the present invention is to provide a method for manufacturing a photoreceptor that has excellent spectral sensitivity and exhibits less deterioration in exposure sensitivity even after repeated image reproduction operations. In a method for manufacturing a photoreceptor comprising a charge transport layer, a photocarrier generation layer that generates carriers upon receiving light irradiation, and a conductor layer, a selenium (Se) layer is provided as a charge transport layer on the conductor layer. a step of forming a SeTe alloy layer by vapor deposition at a temperature in a range in which the selenium layer does not crystallize; a step of forming a SeTe alloy layer as a photocarrier generation layer on the selenium layer by vapor deposition; The method is characterized by comprising a step of performing heat treatment at a high temperature.

Preferred embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the structure of a photoreceptor to be manufactured by the photoreceptor manufacturing method according to the present invention, in which 1 is a conductive substrate, 2 is a charge transport layer made of selenium (Se), 3
4 is a photocarrier generation layer made of a selenium telluride alloy (SeTe), and 4 is a blocking layer.

The method for manufacturing a photoreceptor as shown in FIG. 1 begins with a conductor layer 1.
A selenium (Se) layer 2 is formed on top by a vapor deposition method at a temperature within a range where Se does not crystallize to form a charge transport layer, and this Se
A SeTe alloy layer is formed on the layer by vapor deposition to serve as a photocarrier generation layer.

After forming the yielding eTe alloy layer, 60qo~80q0
A blocking layer 4 is formed on the surface of the eTe alloy layer to be examined by heat treatment at a temperature in the range of 20 minutes.

The photoreceptor thus obtained is hereinafter referred to as a sample for convenience. FIG. 2 is a measurement diagram showing the photosensitivity of the aforementioned sample.

In Fig. 2, the axis represents the wavelength of light irradiated onto the photoreceptor, and the vertical axis represents the energy EH required to halve the surface potential of the uniformly charged photoreceptor through exposure. Less light energy is required to reduce the surface potential by half, the sensitivity to light irradiation is excellent, and a more detailed reproduced image can be obtained.

As the measurement method shown in Figure 2, in the electrophotographic production process,
After the surface of the photoconductor is uniformly charged by corona discharge, which is normally performed, the surface potential is halved when the surface of the carrier transfer layer of the photoconductor is irradiated with light of a specific wavelength using the light source L shown in Figure 1. This represents the light energy EH required to do so. In FIG. 2, △ indicates the characteristics of a conventional photoreceptor having only a Se layer without a SeTe layer as a carrier generation layer, and the mark indicates a case where 10% by weight of Te is contained in Se as the photocarrier generation layer. The characteristics of 0 and ◎ are SeT with Te content of 15% by weight and 20% by weight, respectively.
The characteristics are shown when e-alloy is used as the photocarrier generation layer.

As is clear from FIG. 2, as the content of Te in the photocarrier generation layer increases, the half-life exposure sensitivity improves. For example, when the wavelength of the irradiation light is 50 m, It can be seen that when the content is 2% by weight, the half-life exposure energy is about one order of magnitude smaller than that of the conventional photoreceptor indicated by the symbol △, indicating that the exposure sensitivity is excellent.

Furthermore, as is clear from FIG. 2, the photocarrier generation layer Te
As the content increases, the exposure sensitivity also improves to long-wavelength irradiation light.

In this way, compared to conventional photoreceptors, the photoreceptor according to the present invention not only has superior photosensitivity to irradiation light of the same wavelength, but also has superior photosensitivity to irradiation light of longer wavelengths, such as a semiconductor laser. It has sufficient photosensitivity even for light, making it possible to downsize the electrophotographic apparatus.

The reason why it has such excellent photosensitivity in the short wavelength region is that the SeTe alloy of the photocarrier generation layer 3 has a higher quantum efficiency than Se.

In addition, it has superior sensitivity to irradiation light with longer wavelengths than conventional photoreceptors because it has a hand gap that corresponds to the concentration of the SeTe alloy that forms the photocarrier generation layer 3. This is because it has a high photocarrier generation capacity with respect to light.

Figure 3 shows the exposure sensitivity of a sample in which a SeTe alloy containing 2% by weight of Te was used as the photocarrier generation layer, and after the photocarrier generation layer was formed with the SeTe alloy, it was heat-treated between two vessels at a temperature of 70q0. Deterioration test results are shown, the vertical axis shows the reciprocal of the half-decreased exposure energy EH, and the mechanical axis shows the number of repetitions of uniform charging and light irradiation.

In Fig. 3, the characteristic curves with subscripts P, P2 indicate the measured values when the sample was post-treated at a temperature of 70 oo for 20 minutes, and the characteristic curves with subscripts P3, P4 indicate the post-treatment of the sample. Measured values are shown without.

As is clear from the characteristic curve P in Fig. 3, in the case of a sample post-treated at a temperature of 700C for 20 minutes, when the surface potential of the photocarrier generation layer 3 is about 520V, uniform charging and repeated light irradiation are performed. The uniform charging potential is maintained at a constant value regardless of the number of times, and the reciprocal of the half-reduced exposure energy at that time is the measurement curve P.
As is clear from 2, there is almost no change.

On the other hand, when the sample is not subjected to post-treatment, that is, when the characteristics are investigated immediately after the formation of the photocarrier generation layer, the subscript P
As is clear from the characteristic curve labeled 3, the uniform charging potential rapidly decreases in proportion to the number of repetitions of uniform charging and light irradiation, and the charging potential is extremely low at 60 V at its peak value. , as can be seen from the characteristic curve P4, there is also a large change in exposure characteristics.

When post-treatment is applied to the sample, the properties are stabilized because of the yielding eTe present during the formation of the SeTe layer.
This is thought to be because structural defects in the layer are reduced by low-temperature heat treatment. Figure 4 shows the investigation of the effect of processing temperature in the post-treatment of the sample, where the horizontal axis represents the processing temperature and the vertical axis shows the effect of the sample on a corona charger to which a constant voltage (porridge V) was applied. The surface potential representing the charge retention state after uniformly charging the carrier transport layer is shown.

Subscript M. The curves with ``mark'' indicate the measurement results when the polarity of the charges on the photocarrier generation layer is positive, and the curves with subscripts indicate the measurement results when the polarity of the charges on the photocarrier generation layer is negative.

As is clear from Figure 4, the treatment temperature is 60℃~80q.
In the range of o, the surface charge retention ability is excellent, and when the treatment temperature is below 60q0 or above 80q0, the surface charge holding ability decreases rapidly.

This is because an oxidized layer of the SeTe alloy layer, which is a photocarrier generation layer, is formed on the surface of the SeTe alloy layer as a photocarrier generation layer by heat treatment at a temperature of 60 to 80 degrees, and this oxidized layer functions as a blocking layer against surface charges. ,
This is because the resistance in the thickness direction of the oxide layer increases and leakage of charged charges decreases.

Furthermore, when negatively charged, the surface potential rapidly decreases at around 65o0 or higher, which is evidence that the carrier conductivity type of the SeTe layer has shifted more to the P type. As is clear from the above description, the exposure sensitivity of the photoreceptor obtained by the photoreceptor manufacturing method according to the present invention does not change even after repeated electrophotographic printing operations, and the photoreceptor There is little leakage of charged charges on the surface of the carrier transfer layer, and in the printing process of electrophotography, there is little leakage of charged charges after the uniform charging process, and a high potential is maintained. Using the body in an electrophotographic device has the advantage that high-quality reproduced images can be repeatedly obtained.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the structure of a photoconductor obtained by the photoconductor manufacturing method according to the present invention, Fig. 2 is a measurement diagram showing the wavelength dependence of the exposure sensitivity of the photoconductor, and Fig. 3 is a diagram showing the exposure sensitivity of the photoconductor. Fig. 4 is a measurement diagram showing the relationship between post-treatment temperature and surface potential holding ability. 1: Guide layer, 2: Charge transport layer, 3: Photocarrier generation layer, 4: Grocking layer. Many drawings Tsutomu 2 drawings 3 drawings 4 drawings

Claims (1)

[Claims] 1. A method for producing a photoreceptor comprising at least a charge transport layer, a photocarrier generation layer that generates carriers upon receiving light irradiation, and a conductor layer, wherein selenium (Se) is provided as a charge transport layer on the conductor layer. forming a layer by vapor deposition at a temperature in which the selenium layer does not crystallize; forming a SeTe alloy layer as a photocarrier generation layer on the selenium layer by vapor deposition; 1. A method for producing a photoreceptor, comprising the step of performing heat treatment at a temperature in the range of 80°C.