JPS60189753A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve carrier generaion efficiency and to elevate sensitivity by controlling the surface of a conductive substrate supporting a functionally separated laminate structure type photosensitive layer to specified surface roughness. CONSTITUTION:The max. surface roughness of the conductive substrate of a functionally separated laminate structure type photosensitive body is controlled to 0.5-10 times the thickness of an electrostatic charge generating layer, and its average surface roughness is set to 0.2-5 times the thickness. When a metallic cylinder is used for its substrate, it cah be directly treated by chemically grinding or electrolytically grinding it. When a metal is vapor-deposited on a resin, the resin substrate is treated with plasma to roughen the surface, and a conductive material is vapor-deposited, or the resin substrate is not treated and vapor deposition conditions are properly controlled, and thus, preferable surface roughness can be attained. Since the substantial area between the conductive substrate and the charge generating layer can be enlarged, the obtained photosensitive body is high in charge generating efficiency and high in sensitivity, improved in adhesion of the photosensitive layer to the substrate, improved in mechanical strength, and enhanced in durability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electrophotographic photoreceptor, and more particularly, to a laminated electrophotographic photoreceptor in the Carlson system.

[Technical background of the invention]

In recent years, semiconductor lasers have come to be used as light beams in printers using electrophotography, but since the oscillation wavelength of semiconductor lasers is long at approximately 800 nm, electrophotography that can maintain high sensitivity even in this long wavelength range Photoreceptors are being actively developed.

In the early stages of development, a photoconductor with a single layer of photoconductor layered on a conductive support was used, but at present, photoconductors with a structure in which the photoconductor is separated into a charge generation layer and a charge transport layer are used. A photoreceptor is used.

In the latter photoreceptor, the charge-generating layer is thinner than the charge-transporting layer and has weaker strength, so the charge-transporting layer is usually the top layer and the charge-generating layer is the middle layer. There is.

As the material for the charge transport layer of the photoreceptor, since there is no need to generate charges in the layer, a charge transport substance having excellent charge retention and charge transport abilities is used.1 As a result, the latter described above The former photoreceptor has better sensitivity, chargeability, etc. than the former photoreceptor.

The charge transport material is transparent to visible light, and examples of such materials include polymeric organic semiconductors such as polyvinylcarbazole or its derivatives; low-molecular organic semiconductors such as oxadiazole derivatives, triphenylamine derivatives, or pyrazoline derivatives. in an organic binder such as polyester resin (
= Dispersed ones are known. These charge transport materials are capable of transporting holes, but not electrons. As the charge generating substance, dyes such as copper phthalocyanine are usually used, and as the conductive support, an At plate or a polyethylene terephthalate resin film on which a metal such as At is vapor-deposited is used. .

The electrostatic latent image formation mechanism of the above-mentioned photoreceptor is thought to be as follows (2) In other words, excitons generated in the charge generation layer by light irradiation are generated within the charge generation layer or between the charge generation layer and the charge generation layer. At the boundary with the charge transport layer, electrons and holes (2) dissociate to generate carriers (holes), and the carriers are injected into the charge transport layer (2) and neutralize the negative charges on the surface of the photoreceptor. (Secondly, an electrostatic latent image is formed.) Meanwhile, electrons migrate to the conductive support.

[Problems with background technology]

In order to improve the sensitivity of such a laminated photoreceptor, it is necessary to increase the number of carriers generated in the charge generation layer and to inject the generated carriers into the charge transport layer without being recombined or captured.

Therefore, the aim was to improve charge generation (=, as a result of various studies, it was discovered that a Schottky barrier (2) occurs at the interface between a conductive substrate such as At and a charge generation layer). (This is what happened.

[Purpose of the invention]

An object of the present invention is to provide a highly sensitive electrophotographic photoreceptor with good carrier generation efficiency.

[Summary of the invention]

The present invention provides an electrophotographic photoreceptor in which a charge generation layer and a charge transport layer are sequentially laminated on a conductive support, in which the maximum surface roughness of the conductive support is 0.0% relative to the thickness of the charge generation layer. 5~
The average surface roughness is 0.2 to 5 times the thickness of the charge generation layer. That is, it is thought that because the surface of the conductive support is rough, the substantial area of the interface with the charge generation layer becomes large, and the number of sites contributing to charge generation increases, resulting in high sensitivity.

Hereinafter, the present invention will be explained in further detail.

The photoreceptor of the present invention uses a support with a large surface roughness for the purpose of increasing the contact area between the charge generation layer and the conductive support. The same photoreceptor is used.

Present invention 1: The W11 conductive material used is At.

Metals such as Ih, Au, Cu, Ni, Sa, Zn, and Ag are used.

As the support, a cylinder of these metals may be used, or a conductive substance may be deposited on a resin.

Adjustment of the surface roughness of the support is carried out as required by the following method. When using a metal cylinder, etc. (-), it can be directly processed by chemical polishing, electrolytic polishing, etc.

On the other hand, when using a resin substrate by vapor deposition, the resin substrate is roughened by plasma treatment or the like, and a conductive material is vapor-deposited thereon.

It is also possible to control the deposition conditions without treating the resin substrate.

If the surface roughness of the support is too large, it becomes difficult to form the charge generation layer as a uniform layer. -If the hands are too small, the effect of the present invention will not be significant.

The charge-generating substance constituting the charge-generating layer is the charge-transporting layer (:
It is preferable that the ionization energy is higher and the Fermi level is higher than that of the charge-transporting material. The layer usually has a thickness of 0.1 to 1 μm.

The charge generating substance has the function of supplying holes to the charge transport layer to neutralize the negative charges of the layer, and has the function of supplying holes to the charge transport layer, and has the function of neutralizing the negative charges in the layer, and
400-900 nm) It is an organic semiconductor material having a t-absorption band. As the substance, any substance that has been conventionally used as a charge generating substance in electrophotographic photoreceptors can be used, but aromatic dyes are usually used.

Specific examples include phthalocyanines such as copper phthalocyanine, aluminum phthalocyanine, and germanium phthalocyanine, pyrylium salt dyes, azo dyes, perylene dyes, indigoid dyes, perinone dyes, quinone color chips, anthraquinone dyes, and quinacridone. Examples include dioxazine color pigments, dioxazine color pigments, and cyanine color pigments.

The charge transport layer is made of a hole transport material that is transparent to long wavelength visible light (2 to 50 Pm).
It has a thickness of As the material, a material in which a high-molecular organic semiconductor or a low-molecular organic semiconductor is dispersed in an organic binder is usually used.

〔Effect of the invention〕

According to the photoreceptor of the present invention, since the actual area of the interface between the conductive support and the charge generation layer is wide, a highly sensitive photoreceptor with good charge generation efficiency can be obtained.

Further, the adhesion strength with the conductive support layer is increased, and mechanical strength and durability are improved.

[Embodiments of the invention]

Example 1: Commercially available At plate (maximum surface roughness 0.1μ, average surface roughness 0)
．． 02μ) was chemically polished to obtain a substrate with a maximum surface roughness of 0.6μ and an average surface roughness of 0.4μ. On top of this, a copper phthalocyanine film of 2000Ak was deposited as 420GL.

Then, as a charge transport layer, 60 wt% of the azole derivative of the following formula was applied to a polyester resin (20 μm thick) and dried to obtain an electrophotographic photoreceptor. For comparison, an untreated At Similarly, photoconductors were formed using a plate. When the attenuation of the surface potential due to light irradiation (= photoconductor) was measured using an electrostatic charging test device, it was found that even though the charging potential was the same as 15 oov. Regardless, the half-decreased exposure amount was 4 tux-sec in Example 1, but was 18 tux-sec in Comparative Example.Moreover,
As a result of folding the sample and examining the adhesive strength, it was found that the example did not peel off and had excellent adhesion.

Example 2 A 50μ Mylar film was plasma treated to give a surface roughness of approximately r)′3μ. On the treated surface (2At) was evaporated to form a conductive support with a maximum surface roughness of 02μ and an average surface roughness of 0.1μ.Atop this was a copper phthalociaq monochloride 900A'e shadow-forming charge generating layer. Then, a charge transport layer having the same composition as in Example 1 was formed to a thickness of 20 μm.

As a comparative example, a two-photoreceptor was similarly formed using a substrate in which At was vapor-deposited on an untreated mylar film.

Same as Example 1 A: When the photosensitive characteristics were evaluated, the sensitivity was
It was 5tux*sea and 21tux-sea for the sample that was not necessarily film-treated.

Agent Patent attorney Noriyuki Chikagi (and 1 other person) Continued from page 1 ■Inventor Mizutori Hachimu 1 Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi Tokyo Shibaura Electric Co., Ltd. Research Center

Claims (1)

[Claims] In an electrophotographic photoreceptor in which a photosensitive layer having a laminated structure of a charge generation layer and a charge transport layer is provided on a conductive support, the maximum surface roughness of the conductive support is relative to the thickness of the charge generation layer. , 0.5 to 10 times, and an average surface roughness of 0.2 to 5 times the thickness of the charge generation layer.