JPH01134464A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve wettability of a surface protective layer to an underlying photosensitive layer and to form it through a simple process without any problems of deteriorations of various characteristics of the photosensitive body in an early stage by coating an organic photosensitive body with a surface protective layer made of a nyron-urethane composite film containing dispersed silica. CONSTITUTION:The positively chargeable organic photosensitive body is formed by laminating on a conductive substrate 1 of an aluminum cylinder an electric charge transfer layer 3 containing 1-phenyl-3-(p-diethylaminostyryl)-5-(p- diethylaminophenyl)-2-pyrazoline dispersed in a polyester resin, a charge generat ing layer 2 containing a phthalocyanine azo pigment dispersed in the polyester resin, in a combined thickness of the layers 3, and 2 of 17mum and the surface protective layer 4 formed by coating with a liquid suspension 'Atron(R)' containing nyron, urethane and silica and changing a ratio of nylon/urethane and an amount of silica to be added to said mixture, thus permitting the photo sensitive body prevented from stains due to foreign matter, and scratches to be obtained through a simple process without deteriorations of various characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an electrophotographic organic photoreceptor having a photosensitive layer made of an organic photoconductive material on the surface of a conductive substrate.

[Conventional technology]

Photoreceptors used in electrophotographic devices using the Carlson process are broadly classified into those with a functionally separated multilayer structure and those with a single layer structure, depending on the structure of their photoresist film. The basic structure of the former is a charge generation layer in which pairs of electrons and holes are generated by the incidence of light to form a latent image, and a charge transport layer that transports the generated charges. The basic structure is a single layer with transport capacity.

Since the photosensitive layer is formed by coating, most of the organic photoreceptors that have been put into practical use as low-cost photoreceptors have a charge generation layer 2 on a conductive substrate 1 as shown in FIG. Charge transport I
It was a negatively charged type with a functionally separated multilayer structure laminated in the order of I3. Some researchers are considering a positively charged type in which the charge generation layer 2 and the charge transport layer 1113 are interchanged as shown in Fig. 3, but this layer structure is extremely thin compared to the transport layer by 0.1 to 0.4 -
Since a generation layer with a thickness of A structure of generation layer 2/surface protection N4 has been considered. Until now, photoreceptors provided with a protective layer 4 on their surfaces have been put to practical use only by special electrophotographic methods other than the Carlson process. However, recently, various surface protective layers that can be used in the Carlson process have been proposed. - [Problems to be solved by the invention] In such organic photoreceptors, for example, methods of providing a crosslinked polymer or copolymer as a protective layer, methods of protecting fluororesin, silicone resin, polyester resin, aromatic polyamide resin, etc. A method of providing it as a layer is being considered. However, these methods require a condensation catalyst, which complicates the process. In addition, the substance used for the catalyst may have an adverse effect on the organic photoreceptor, and in the case of forming a cured film, the baking process is required. or the wettability of the photoreceptor surface is poor, requiring advanced techniques for application.
The presence of the protective layer causes problems such as decreased sensitivity of the photoreceptor, occurrence of background fog, and furthermore, an accelerated toner filming cycle.

The object of the present invention is to provide surface protection that has good wettability to the photosensitive layer of the underlayer, which eliminates problems such as deterioration of initial properties of the photoconductor and early toner filming cycle, and which can be formed in a simple process. An object of the present invention is to provide an electrophotographic organic photoreceptor having layers.

[Means for solving problems]

In order to achieve the above object, the organic photoreceptor of the present invention includes:
It has a surface protective layer made of a nylon/urethane hybrid film in which 5ift is added and dispersed.

[Effect]

The nylon/urethane hybrid film does not require the addition of a condensation catalyst or a firing process, and the addition and dispersion of sto makes the film harder and improves its rigidity, and the addition of urethane also strengthens the adhesion to the underlying layer. become.

〔Example〕

As shown in FIG. 1, a conductive substrate 1 of a positively charged organic photoreceptor having a surface protective layer, an aluminum cylinder, a charge transport layer 3
l-phenyl-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)-2- using polymethyl methacrylate polymer <PMMA) as a binder.
Pyrazoline (ASPP), charge generation F! Polyester resin in which a phthalocyanine azo pigment was dispersed in No. 12 was used, respectively. The combined thickness of the charge transport layer 3 and the charge generation layer 2 is 17n. Furthermore, the surface protective layer 4 was applied to the east side using Nylon CM-4000 (product name), urethane manufactured by Kansai Paint ■, and Atron NSL-300 manufactured by Nippon Soda ■, which is a SiOx suspension, and the blending ratio of nylon and urethane was determined using SIO. , were formed by changing the addition rate of , and three types of photoreceptors were prepared. As a comparative example, a photoreceptor having the structure shown in FIG. 3 without the protective layer 4 was prepared. The characteristics of these photoreceptors are shown in Table 1. The dark decay rate is the potential decay per second;
The residual potential indicates the potential after exposure of 5 μJ/−, and the exposure was performed using light with a wavelength of 780 nm.

Although the organic photoreceptor of Example 1 in Table 1 has a slightly increased residual potential, it operates without any problem in actual use. Further, since the protective film itself is very firmly attached to the underlayer, it has excellent damage resistance, and it is possible to provide a photoreceptor that is compatible with various copying processes.

In the photoreceptor of Example 3, the increase in residual potential is small, and the adhesion of the film is at a nearly satisfactory level. However, this film wears out quickly in the electrophotographic process where relatively strong stress is applied to the photoreceptor, such as when installed in a copying machine with a blade cleaning mechanism, so the contact between the cleaning mechanism and the photoreceptor is Consistency needs to be understood.

In the photoreceptor of Example 2, the increase in residual potential was small, and the film adhered very firmly to the underlying layer.

Furthermore, since the film is hard and the film wears little during printing, it is possible to provide a photoreceptor suitable for high-speed copying processes.

Incidentally, it was observed that toner filming occurred slowly in all of the photoreceptors of Examples.

[Effects of the Invention] According to the present invention, urethane is mixed with nylon resin that does not require a curing process to improve the adhesion with the base layer.
(By adding and dispersing h to harden and form a surface protective layer, an electrophotographic organic photoreceptor that is protected from contamination and damage by foreign substances can be obtained in a simple process without deteriorating various properties. The present invention is particularly effective for positively charged organic photoreceptors in which the charge generation layer is on the surface side, but even when applied to negatively charged organic photoreceptors, there is no wear on the charge transport layer on the surface side, and various characteristics are maintained. can also be stabilized.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a photoreceptor in which the present invention is implemented, FIG.
FIG. 3 is a cross-sectional view of each photoreceptor without a surface protective layer. l: conductive substrate, 2: charge generation layer, 3: charge transport layer, 4
: Surface protective layer. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1) An organic photoreceptor for electrophotography characterized by having a surface protective layer made of a nylon/urethane hybrid film to which silicon dioxide is added and dispersed.