JP2819037B2 - Function-separated selenium photoconductor for electrophotography - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a function-separated selenium photosensitive member for electrophotography, and more particularly to a function-separated selenium photosensitive member for a reversal developing type electrophotographic apparatus.

(Prior Art and Problems to be Solved) In a laser beam printer, which has been widely spread in recent years, a conductive substrate (1), a charge transfer layer (2), and a charge generation layer (3) as shown in FIG. A so-called function-separated selenium photoconductor comprising a surface protective layer (4) provided depending on the type of the photoconductor is often used.

Also, contrary to the reversal development method, that is, the normal development method that forms an image with an exposed portion as a white background, toner is adhered to the exposed portion, A so-called reversal development method in which an image is formed with an exposed portion as a white background portion is widely used.

By the way, in a laser beam printer as described above, high resolution is strongly demanded for improving image quality. It is required that the dark decay characteristic indicating the coercive force and the residual potential characteristic indicating the potential at the exposed portion be excellent.

In other words, if the dark decay is poor, the surface charge is difficult to be retained, so that not only the toner adheres to the unexposed portion (high potential portion), which is a white portion, causing "ground fog" or black spots, but also the surface other than the exposed portion. This lowers the potential by lowering the potential.

Also, when the residual potential is increased, the amount of toner adhered to the exposed portion is reduced, which causes a decrease in density, which also causes a decrease in resolution.

By the way, as a means for improving the dark decay which causes the generation of "fog" and black spots on a white background, the amount of negative charge injected from the conductive substrate (1) into the selenium layer (2) in FIG. 1 is suppressed. Is known to be effective, and in order to reduce the residual potential, it is effective to reduce positive charge traps in the photoconductor.

In order to improve the dark decay characteristics, it is important to not only suppress the amount of injected negative charges, but also to achieve a uniform surface potential based on the surface properties of the conductive substrate (1).

Therefore, as shown in FIG. 2, a selenium layer (5) containing halogen is provided at the interface between the conductive substrate (1) and the charge transfer layer (2) as an undercoat layer of the conductive substrate (1) to provide dark decay. A selenium photoreceptor with improved characteristics has been proposed.

(Object of the Invention) The present invention provides a photoreceptor having improved not only dark decay characteristics but also residual potential characteristics so as to meet the demand for high resolution in laser beam printers and the like.

(Means of the Present Invention for Solving the Problems) As shown in FIG. 3, the present invention provides a selenium layer containing halogen (see FIG. 2) at the interface between the conductive substrate (1) and the charge transfer layer (2). It has been found as a result of an experimental study that by providing a selentellurium layer (6) containing halogen instead of (5), it is possible to improve not only the dark attenuation characteristics but also the residual potential characteristics.

Further, in this case, if the thickness of the selentellurium layer (6) containing halogen is increased, the level of non-conformities is increased and the temperature characteristic is deteriorated. Therefore, the range of the thickness is preferably 0.1 to 8 μm. Also, since the addition amount of the halogen element has the same tendency as the film thickness, it is clear that the addition amount range is preferably about 2 to 30 ppm, and the addition amount of tellurium is preferably 2 to 15 w%. It has been found that by appropriately selecting these, it is possible to improve the dark decay characteristic and the residual potential characteristic, and to realize a high quality image.

 Next, examples of the present invention will be described.

(Example 1) A selenium / tellurium layer (6) containing halogen having a tellurium concentration of 100 w%, a halogen concentration of 10 ppm, and a film thickness of 3 μm was deposited on an aluminum drum surface serving as a conductive substrate (1), and a high-pressure layer was formed thereon. Purity selenium (purity of 99.999% or more) with a film thickness of 50 μm
To form a charge transfer layer (2). Furthermore, a charge generation layer (2) made of a selenium tellurium alloy layer having a tellurium concentration of 50 w% and a film thickness of 0.2 μm is formed thereon, and an arsenic concentration of 2 w
%, A surface protective layer (4) made of a selenium arsenide alloy having a thickness of μm was deposited.

(Example 2) The halogen concentration of the selenium / tellurium layer (6) containing halogen in Example 1 was set to 1 ppm.

Example 3 The halogen concentration of the selenium / tellurium layer (6) containing halogen in Example 1 was set to 40 ppm.

(Example 4) The selenium / tellurium layer (6) containing halogen in Example 1 was set to a film thickness of 15 µm.

These Examples 1, 2, 3, 4 and selenium containing halogen
When the image characteristics and the electric characteristics of the photoconductor without the tellurium layer were compared, the results shown in Table 1 were obtained.

The criteria are as follows.

Judgment standard Resolution: A laser beam printer with a resolution of 240 to 400 DPI must be able to read a line image created with a beam of 1 dot on-off.

○ Legible △ Bokel × Not legible Dark decay: After charging + 800v on the photosensitive drum in the dark,
Potential holding ratio after 5 seconds.

○ 90% or more △ 80% or more × less than 80% Residual potential: The potential after static elimination in the developing process of a laser beam printer.

○ 40 v or more △ 60 v or less × more than 60 v (Effects of the Invention) As is apparent from the above description, according to the present invention, it is possible to provide a selenium photoreceptor capable of obtaining a high-resolution image required for a laser beam printer or the like. It becomes possible.

[Brief description of the drawings]

1 and 2 are explanatory diagrams of the prior art, and FIG. 3 is an explanatory diagram of one embodiment of the present invention. (1) ... conductive substrate, (2) ... charge transfer layer, (3)
... A charge generation layer, (4) a surface protective layer, (5) a selenium layer containing halogen, and (6) a selenium / tellurium layer containing halogen.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-158845 (JP, A) JP-A-54-70838 (JP, A) JP-A-64-76066 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) G03G 5/00-5/16

Claims (1)

(57) [Claims] 1. A function-separated selenium photoconductor in which a charge transfer layer and a charge generation layer are sequentially laminated on a conductive substrate, wherein a selenium layer to which arsenic is added is provided as a surface protection layer on the charge generation layer. A selenium / tellurium layer having a thickness of 0.1 to 8 μm is added between the conductive substrate and the charge transfer layer by adding 2 to 30 ppm of halogen and having a tellurium concentration of 2 to 15 w%. Separated function selenium photoconductor for electrophotography.