JP2638185B2 - Manufacturing method of photoreceptor for electrophotography - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a digital copying machine, a laser printer, and the like, having a photosensitive layer made of a selenium-based photoconductive material on a base made of a material mainly containing aluminum. The present invention relates to a method of manufacturing an electrophotographic photoreceptor suitably used for a facsimile, a facsimile or a light emitting diode printer.

[Conventional technology]

In recent years, high-speed positive-charging type devices such as laser printers, facsimile machines, and light-emitting diode printers to which electrophotography is applied have recently been developed to provide highly sensitive electrophotographic photoconductors having a half-attenuation exposure of 0.4 μJ / cm ² (hereinafter simply referred to as photosensitive (Also referred to as the body). Also, in devices such as high-resolution low-speed printers and color digital copiers, in order to improve image reproducibility, dark decay is small,
There has been a demand for a photoreceptor having stable performance with little fatigue such as a decrease in charged potential and an increase in residual potential.

In response to such a request, the applicant has
A function-separated type photoconductor in which a carrier transport layer, a carrier generation layer, and a surface protection layer are sequentially laminated on a conductive substrate,
On a carrier transporting layer made of pure selenium or a selenium-tellurium alloy having a low tellurium concentration, a carrier generating portion having a high tellurium concentration and a selenium-tellurium alloy interposed between the carrier generating portion and the carrier transporting layer are formed. Photoreceptor in which a carrier generating layer composed of a carrier injecting portion having a high tellurium concentration on the carrier generating portion side and continuously decreasing toward the carrier transport layer side is provided, and a surface protective layer is formed thereon No. 61-52648). In addition, a carrier layer composed of a selenium-tellurium alloy having a high tellurium concentration is formed on a carrier transport layer composed of pure selenium or a selenium-tellurium alloy having a low tellurium concentration by interposing a trap layer composed of a selenium alloy containing a halogen of 5 to 5000 ppm. A photoreceptor in which a layer is provided and a surface protective layer is further formed thereon has been proposed (JP-A-61-52650).

[Problems to be solved by the invention]

In the photoreceptor having the above-described configuration, the thickness of the carrier generation layer and the tellurium concentration particularly greatly affect sensitivity, dark decay, and fatigue. The film thickness is required to be 0.1 μm or more to prevent time-dependent changes. However, when the film thickness is 0.3 μm or more and the tellurium concentration is 48% by weight or more, dark decay and fatigue become large. The material and the film thickness, especially the tellurium concentration gradient at the carrier injection portion or the halogen amount and the film thickness of the trap layer have been optimized, but a high level of technology is required in manufacturing. Further, as the applications of photoreceptors for long-wavelength light such as laser printers have been expanded, demands for characteristics have become more severe, and there has been a demand for improvements in characteristics, particularly, in dark attenuation and fatigue in repeated use.

The present invention has been made in view of these points, and is suitably used in an electrophotographic apparatus which has high sensitivity, has little dark attenuation and fatigue in repeated use, and uses long wavelength light as an exposure light source. It is another object of the present invention to provide a method for easily producing a photosensitive member having stable performance.

[Means for solving the problem]

According to the present invention, the object of the present invention is to boil the surface of a substrate made of a material containing aluminum as a main component in pure water such that an aluminum oxide film having a degree of oxidation by ESCA analysis of 3.50 or more is formed. This is achieved by forming a photosensitive layer including a charge transport layer composed of pure selenium and a carrier generation layer composed of a selenium-tellurium alloy containing 40 to 42% by weight of tellurium on the substrate.

[Action]

When the substrate treated by the method of the present invention is used, the sensitivity of the photoreceptor can be improved without increasing the tellurium concentration of the selenium-tellurium alloy forming the carrier generation layer or increasing the thickness of the carrier generation layer. Thus, a photosensitive member having high sensitivity can be obtained without worsening dark decay and fatigue in repeated use. Also, when photoconductors having the same sensitivity are manufactured, the tellurium concentration in the carrier generation layer can be reduced, so that dark decay and fatigue are reduced, and photoconductors with more stable performance in repeated use can be obtained. become.

〔Example〕

Example 1 An outer surface of a cylindrical aluminum alloy tube having a diameter of 80 mm as a substrate of a photoreceptor was processed with a grindstone or a cutting tool, and the center line average roughness Ra was 0.7 μm, waviness was 0.35 μm, and average distance between surface irregularities. After the surface of Sm is 30 μm, the surface is degreased with trichlene, followed by surface oxidation treatment in pure water at a temperature of 90 ° C. for 15 minutes.
The mixture was boiled for minutes to form an aluminum oxide film. This substrate was mounted on a rotating support shaft of a vacuum evaporation apparatus, and the substrate temperature was set to 54 ° C.
While rotating, the bell jar temperature of the vacuum chamber is set to 40 ° C.
In a vacuum of 2 to 4 × 10 ^-5 Torr, a carrier transport layer made of pure selenium having a thickness of 48 μm and a carrier having a thickness of 0.15 μm made of selenium-tellurium alloy containing 42% by weight of tellurium are placed in a vacuum at 2 to 4 × 10 ^-5 Torr. A generating layer and a surface protective layer of 2 μm in thickness made of a selenium-arsenic alloy containing 3% by weight of arsenic are sequentially vacuum-deposited to obtain a photoconductor. Thus, 30 photoconductors were produced.

FIG. 1 is a schematic cross-sectional view of a photoreceptor manufactured by the method of this embodiment, in which an aluminum oxide film 2 is formed on a surface of a base 1 made of an aluminum alloy, and a carrier transport layer 3 is formed thereon. , A carrier generation layer 4 and a surface protection layer 5 are sequentially provided.

Example 2 Thirty photoconductors were produced in the same manner as in Example 1, except that a selenium-tellurium alloy containing 40% by weight of tellurium was used as a vapor deposition material for the carrier generation layer.

Comparative Examples 1 to 30 For comparison, 30 photoconductors of Comparative Examples 1 to 4 were manufactured in the same manner as in Example 1 except that the method of surface oxidation treatment of the substrate was changed as follows.

Comparative Example 1 No oxidation treatment Comparative Example 2 Heated at 150 ° C for 36 minutes Comparative Example 3 Heated at 250 ° C for 36 minutes Comparative Example 4 Dipped in nitric acid (31.3%) for 20 minutes and then heated at 250 ° C for 36 minutes Sensitivity of the photoconductors of Examples and Comparative Examples by monochromatic light having a wavelength of 780 nm (half-attenuation exposure)
Was measured. Further, the adhesion between the substrate and the photosensitive layer was relatively compared by a peeling test using an adhesive tape (the larger the number, the higher the adhesion strength). Furthermore, the surface of each substrate of the same batch subjected to surface oxidation treatment in the same manner as each photoconductor was subjected to X-ray electron spectroscopy (ES
CA), the intensity ratio of emitted electrons between aluminum oxide and aluminum metal (degree of oxidation: Alox / Almetall) and the thickness and morphology of the oxide film were examined.

Further, with respect to these photoreceptors, fatigue and dark decay in repeated action were measured by an evaluation process equivalent to the laser printer process shown in the conceptual diagram of FIG. 3, and evaluated as repetition characteristics. In FIG. 3, reference numeral 11 denotes a photoconductor, 12 denotes a charger for charging the photoconductor surface, 13 denotes a laser beam having a wavelength of 780 nm,
Is a developer, 15 is a charger for transfer, 16 is a charger for separating paper, 1
Reference numeral 7 denotes a static elimination light source. These are arranged so as to have the arrangement central angle shown in the drawing with respect to the central axis of the drum-shaped photoconductor 11. The charger 12 for charging the photoreceptor surface uses a scorotron, DC5.2kV for transfer charging, AC4.2kV, 500Hz for paper separation charging
(Maximum amplitude), and neutralization was performed using a Ne lamp. In such an evaluation process, processes such as charging and exposure were repeated while rotating the photoconductor 11 in the direction of arrow A, and fatigue and dark decay after 250 cycles were measured. Fatigue is a decrease in potential with respect to the initial surface charge level, and dark decay is a potential retention rate one second after surface charge.

 Table 1 shows the results of the above surveys and measurements.

The OH in the form of FIG. 1 indicates that an OH group was recognized by ESCA analysis.

FIG. 2 shows the same 42% by weight as the carrier generation layer.
FIG. 5 is a graph showing the relationship between the sensitivity (average value) of each photoconductor of Examples 1 and Comparative Examples 1 to 4 and the degree of oxidation of the surface of a substrate using a selenium-tellurium alloy containing tellurium and having a film thickness of 0.15 μm. It is.

From Table 1 and FIG. 2, it can be seen that the photoreceptor of Example 1 has higher sensitivity than the photoreceptors of Comparative Examples 1 to 4, and that the repetition characteristics of fatigue and dark decay characteristics are also improved. As can be seen, as shown in FIG. 2, there is no direct relationship between the degree of oxidation of the substrate surface and the sensitivity, and as shown in Table 1, the thickness and morphology of the oxide film Therefore, the improvement of sensitivity and repetition characteristics cannot be properly explained. However, it is necessary to improve the sensitivity and repetition characteristics of the photoreceptor, and it is extremely effective that the substrate is boiled in pure water to form an oxide film, and that the degree of oxidation by ESCA analysis is particularly 3.50 or more. It is clear.

Furthermore, based on the results of the photoreceptors of Example 2 and Comparative Examples 1 to 4 in Table 1, if the sensitivity can be at the same level, it is possible to use a substrate having an oxide film formed by boiling in pure water. It can be seen that the tellurium concentration of the selenium-tellurium alloy used for the carrier generation layer can be reduced, and the repetition characteristics can be greatly improved.

Further, by performing such a boiling treatment, as shown in Table 1, the adhesion between the substrate and the photosensitive layer is also improved, which is effective in improving the reliability of the photoreceptor.

〔The invention's effect〕

According to the present invention, the surface of a substrate made of a material containing aluminum as a main component is boiled in pure water so as to form an aluminum oxide film having a degree of oxidation of 3.50 or more by ESCA analysis, and then the pure surface is formed on the substrate. A charge transport layer made of selenium;
By forming a photosensitive layer including a carrier generation layer made of a selenium-tellurium alloy containing 40 to 42% by weight of tellurium, the tellurium concentration of the selenium-tellurium alloy forming the carrier generation layer can be increased, The sensitivity of the photoreceptor can be improved without increasing the film thickness, and dark decay and fatigue in repeated use can be reduced. In addition, the tellurium concentration of the carrier generation layer can be reduced or the thickness thereof can be reduced without lowering the sensitivity of the photoreceptor, thereby greatly improving dark attenuation and fatigue in repeated use. It becomes possible.

Thus, a photosensitive member having high sensitivity, low dark decay, little fatigue, and stable performance can be easily manufactured without employing a photosensitive layer configuration having a carrier injection portion or a trap layer. It is possible to provide a photoreceptor that is suitably used for an electrophotographic apparatus using an exposing light source of a long wavelength light.

Further, the adhesion between the substrate and the photosensitive layer is improved, and the effect of improving the reliability of the photoconductor is also obtained.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a photoreceptor manufactured by the method of the embodiment of the present invention, FIG. 2 is a plot showing the relationship between the sensitivity of the photoreceptor and the degree of oxidation of the substrate surface, and FIG. It is a conceptual diagram which shows the evaluation process of the repetition characteristic of. DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Aluminum oxide film, 3 ... Carrier transport layer, 4 ... Carrier generation layer, 5 ... Surface protective layer.

Claims (1)

(57) [Claims] 1. A surface of a substrate made of a material containing aluminum as a main component is boiled in pure water so as to form an aluminum oxide film having an oxidation degree of 3.50 or more by ESCA analysis. Charge transport layer comprising 40 to 42
A method of manufacturing a photoconductor for electrophotography, comprising forming a photosensitive layer including a carrier generation layer made of a selenium-tellurium alloy containing tellurium by weight.