JPS62170967A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body superior in char acteristics by forming a photosensitive layer made of ZnO specified in crystal structure on a conductive substrate. CONSTITUTION:The electrophotographic sensitive body is provided on the conduc tive substrate with the photosensitive layer obtained by growing the ZnO crystals having columnar crystals of wurtzite structure with their C-axes perpendicular to the conductive substrate. This ZnO layer is formed by the sputtering method or the like, and when the sputtering is executed by using ZnO as a target, the columnar crystals of ZnO oriented to the C-axes, and each layer of Zn<++> and each layer of O<--> are alternately laminated on each other, and the electric polarizations composed of these positive and negative ions are laminated to exhibit great polarization in the direction of the C-axis, thus permitting the obtained photosensitive body comparatively thin in film thickness to obtain sufficient electrifiable potential and high sensitivity by using such high polariza tion potential and high photoconductivity of the ZnO.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electrophotographic photoreceptor containing zinc oxide as a main component.

(Prior Art and its Problems) Amorphous Noricon (hereinafter referred to as a-Si) is generally used as an electrophotographic photoreceptor. a
-S i is widely used because it has higher sensitivity, is harmless, and has a longer life than conventionally used amorphous selenium or its compounds.

However, a-Si is very expensive due to its slow film formation rate, expensive raw material gases, and low yield of a-Si, and there are problems in its widespread application to general electrophotography. .

Recently, organic semiconductor photoreceptors have also been attracting attention.
It is still not as good as a-S i in terms of lifespan. Although zinc oxide has been used in the past, sufficient photoreceptor characteristics have not always been obtained.

(Objective of the Invention) The object of the present invention is to obtain an electrophotographic photoreceptor having excellent characteristics.

(Contents of the Invention) That is, the present invention provides an electrophotographic photoreceptor having a photoreceptor layer in which zinc oxide having columnar crystals with a Wurz structure is grown on a conductive substrate with the C axis of the crystal perpendicular to the substrate. do.

In the present invention, use zinc oxide. As mentioned above, zinc oxide was actually once widely used as an electrophotographic photoreceptor, and the material itself was widely known to have high photoconductive properties.In this case, however, zinc oxide powder was mixed into an organic resin. Needed as a photoreceptor by dispersing it! 013~14Ω
High resistance of ctn was obtained. However, a material in which zinc oxide powder is dispersed in an organic resin has a high electrical resistance and at the same time a low photoconductivity. Further, since the powder has a large surface area and the surface electronic state increases significantly, it has an adverse effect on the photoconductivity properties and the properties of the photoreceptor. That is, although pulverization itself is not necessarily preferable because it deteriorates the photoconductive properties, it is unavoidable to pulverize it and composite it with resin in order to improve the charging properties.

However, in the present invention, zinc oxide is not composited, but rather crystallized to align the C-axis of zinc oxide, and C
It is characterized by the ability to easily provide the surface charging potential required for electrophotography by utilizing the polarization effect in the axial direction.

The zinc oxide layer of the present invention having a specific crystal structure is formed using an ion engineering method such as sputtering. Sputtering using ZnO as a target is most preferred. According to ion engineering methods, C-axis oriented ZnO
As the crystal grows, layers consisting of zinc ions and oxygen are stacked alternately, and the electrical polarization of these positive and negative ion layers stacks up to create a large polarization in the C-axis direction. show.
In addition to zinc oxide, ions of other elements such as lithium ions, copper ions, gallium ions, or a mixture thereof are preferably included during the production of the photoreceptor layer. Ions of these elements are added in small amounts to zinc oxide to obtain the high resistance required for the photoreceptor.

Examples of compounds that are actually added include CuCC.

The amount added is 0.01 to 1 per 1.00 parts by weight of zinc oxide.
O parts by weight.

The conductive substrate used as the substrate may be a metal, such as aluminum, or another resin substrate, such as a resin substrate blended with conductive carbon.

(Effects of the Invention) In electrophotography, it is necessary to maintain a charged potential on the surface of a photoreceptor, and the surface potential must be eliminated by irradiation with light. To maintain this charge, the polarization potential generated by the C-axis orientation of zinc oxide is used, and at the same time, the high photoconductivity of zinc oxide is used to obtain a sufficient charging potential and high sensitivity for a photoreceptor with a relatively thin film thickness. becomes possible. The materials used in the present invention are non-polluting and inexpensive and available anywhere.

The present invention will be explained in more detail with reference to Examples.

(Example) Example! 0.3% by weight of CuCC was mixed into ZnO and fired. 1
Using magnetron sputtering from a target with a diameter of Oct11, the mixing ratio of argon and oxygen at about 0.1 Torr was 7:
Approximately 10cm square thickness () using sputtering gas of 3.
An experiment was conducted by depositing a thin film of ZnO:Co to a thickness of approximately 15 μm on a 2 mm aluminum plate.

When this film was oriented with X-rays, the (002) diffraction line of ZnO was observed as shown in Figure 1, which clearly confirmed that the C-axis was oriented perpendicular to the substrate. It was done. Immediately after attaching this temporary aluminum film with the ZnO thin film to an aluminum drum and positively charging the surface with a +6000V corona discharge, the potential was measured using an electrometer (TREK365 model) with a 3627 model transparent probe. I got 398v. The charge retention rate after 1 second was good at about 75%, and when the light intensity of daylight fluorescent light was adjusted to about 2 lux through a filter and irradiated, the charge potential was halved in less than 0.5 seconds. did. Further, the residual potential was below IO■. From this, it is clear that the oriented zinc oxide thin film functions as an excellent electrophotographic photoreceptor.

[Brief explanation of drawings]

The second figure is an X-ray measurement diagram of the electrophotographic photoreceptor obtained in Example 1.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor having a photoreceptor layer in which zinc oxide having columnar crystals with a Wurz structure is grown on a conductive substrate with the C-axis of the crystal perpendicular to the substrate. 2. The electrophotographic photoreceptor according to item 1, wherein the photoreceptor layer contains, in addition to zinc oxide, an element selected from the group consisting of lithium, copper, and gallium.