JPS647381B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a photoreceptor in which a selenium (Se) layer, a selenium telluride (SeTe) layer, and a selenium layer are sequentially laminated.

Conventionally, photoreceptors with high sensitivity to long wavelengths such as semiconductor laser printers have been manufactured on aluminum (A) substrates.
A photoreceptor in which Se/SeTe/Se are sequentially laminated has been proposed, but if this photoreceptor is repeatedly used in a normal electrophotographic process, carriers will accumulate inside the photoreceptor, especially if the exposure process is performed with long wavelength light. , the initial charging ability deteriorates due to so-called optical fatigue.

These internal charges combine with charged charges in the dark state (before the exposure process), resulting in an afterimage during printing and a decrease in print density.

The purpose of the present invention is to apply it to an electrophotographic photoreceptor that uses long wavelength light such as a semiconductor laser for exposure.
Se/SeTe/Se laminated photoreceptor An object of the present invention is to provide a method for producing the uppermost Se layer so that it can function stably in the normal Carlson process.

As shown in Figure 1, the properties required for Se in the uppermost layer of a Se/SeTe/Se laminated photoconductor include transportability for electrons when a semiconductor laser is used as the exposure source, that is, in the case of long wavelength light. In addition, in the case of copying light, which is visible light, the material must have a transport property for holes. It has been known that Se has hole-transporting properties, and it has actually been used with positive charges, but when using semiconductor laser light and visible light (copying light) together, it is also necessary to make it electron-transporting. .

In the present invention, when forming the uppermost Se layer by vapor deposition, the structure of the amorphous film is changed by maintaining the substrate temperature at a low temperature. The concentration distribution was changed to make it more electronically conductive. Furthermore, electron traps within the film were greatly reduced by slowing down the deposition rate.

Example: Se is deposited on an aluminum substrate at a substrate temperature of 65℃.
It was deposited to a thickness of 50 μm, and SeTe was deposited to a thickness of 2 μm on top of it. The vapor deposited film thus obtained on the substrate was post-baked at 70° C. for 30 minutes in a constant temperature bath. Further Se on the thus obtained Se/SeTe two-layer photoreceptor.
A layer of about 2 μm was deposited at a substrate temperature of 45°C and a deposition rate of
It was set at 0.2 μm/min.

As a comparison sample, a substrate temperature was maintained at 60° C. and the above-mentioned upper layer Se was formed.

The photoreceptor obtained in this way was mounted on the surface of a rotating drum as shown in Figure 2 to form a photoreceptor drum, and the characteristics of the photoreceptor were tested using the usual electrophotographic process called the Carlson process shown in the same figure. I went there.

First, the surface of the photosensitive drum D is uniformly charged with a charger _T1 , and exposed with a semiconductor laser or visible light in the exposure section L. and electrometer K
After measuring the potentials of the exposed and non-exposed areas on the surface of the photoreceptor drum, a developing device G develops the toner image, which is transferred to a recording paper P at a transfer section C.

In order to remove the developer remaining on the surface of the photoreceptor drum, the charge on the developer and the surface of the photoreceptor drum is neutralized using the corona charger T ₂ and the static elimination lamp R, and the cleaner S
Remove residual developer.

Thereafter, the surface of the photoreceptor drum is uniformly charged again by the charger _T1 .

As a result of measuring the characteristics of the photoreceptor according to the present invention as described above, the recording energy for a semiconductor laser with a wavelength of 780 mm is 3 μJ/cm ² and the recording energy for copying light is approximately 2 lux·sec. .

The potential of the non-exposed area (charged potential) and the potential of the exposed area (residual potential) of the surface of the photoreceptor drum were measured using an electrometer K. As shown by the black circles in FIG. It can be seen that the characteristics are improved compared to the characteristics (indicated by white circles).

FIG. 4 shows the results of measuring the charging potential using the apparatus shown in FIG. 2 using photoreceptors obtained when the temperature of the substrate was varied during the formation of the photoreceptor by vapor deposition. The deposition rate of the top Se layer was 0.1 μm/min. As is clear from the figure, when the substrate temperature is below 60° C., the decrease ΔV in the charging potential on the surface of the photoreceptor drum due to repetition of the Carlson process is relatively small.
Note that when ΔV exceeds 100 V, toner unevenness occurs in the reproduced image, resulting in poor quality and is not practical.

Figure 5 shows the change in charging potential △V when using a photosensitive drum using each photosensitive member, which was obtained by changing the deposition rate when forming the uppermost Se layer of the photosensitive member.
This shows that when the deposition rate is 0.5 μm/min or less, a good photoreceptor can be obtained with little change in charging potential after 250 repetitions of the Carlson process step with an exposure wavelength of 770 mm and an initial charge of 1000 V. I understand.

Figure 6 shows the heat treatment performed on the photoreceptor after forming the Se and SeTe layers on the substrate using the above-mentioned vapor deposition technique (i.e., storing the photoreceptor in a constant temperature bath at a constant processing temperature before forming the uppermost Se layer by vapor deposition). ) processing temperature,
It is a diagram showing the relationship between the charging potential of the photoreceptor drum, and it can be seen that the charging potential increases when the processing temperature is between 60°C and 80°C.

This is because at high temperatures of 80°C or higher, the lower Se layer and SeTe layer crystallize, and the electrons in the crystals combine with the positive charges on the photoreceptor drum, resulting in a lower charging potential. This is thought to be because the electrons in the SeTe layer become excessive compared to the holes, and these electrons combine with the charges on the surface of the photoreceptor drum.

As is clear from the above explanation, the method for manufacturing the photoreceptor according to the present invention involves forming the uppermost Se layer on the substrate at a substrate temperature of 60°C or lower and at a deposition rate of 0.5 μm/min, which reduces optical fatigue of the photoreceptor. This method has the advantage that a high-quality reconstructed image can be obtained with less noise.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a photoreceptor, FIG. 2 is a diagram for explaining the Carlson process, and FIGS. 3 to 6 are diagrams showing characteristics of the photoreceptor according to the present invention. T ₁ : Charger, L: Exposure section, K: Electrometer, C:
Transfer section, G: developing device, D: photosensitive drum.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a photoreceptor in which a selenium (Se) layer, a selenium tellurium (SeTe) layer, and a selenium layer as an uppermost layer are sequentially laminated on a substrate, wherein
A method for producing a photoreceptor, characterized in that the layer is formed by vapor deposition at a substrate temperature of 60° C. or less and at a deposition rate of 0.5 μm/min or less. 2 After sequentially forming the Se layer and SeTe layer on the substrate, and before forming the uppermost Se layer, the film was heated in the atmosphere for 60 minutes.
2. The method for manufacturing a photoreceptor according to claim 1, wherein post-baking is carried out at a temperature within the range of 80°C to 80°C.