JP2553586B2 - Electrophotographic photoreceptor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member used in electrophotographic copying machines, optical printers and the like.

2. Description of the Related Art Conventionally known photosensitive materials include inorganic materials such as selenium, zinc oxide, cadmium sulfide, and amorphous silicon, and organic polymers such as anthracene, anthraquinone, and poly-N-vinylcarbazole.
Most of these photoconductor materials are not used alone but used in combination with other materials. The purpose of the combination is, for example, to improve the sensitivity, change the photosensitive wavelength range, improve the durability, impart processability as a coating film, and the like. Examples of the means include alloying, doping, mixing, polymer blending, coating and laminating.

However, in general, high-sensitivity photoconductor materials have poor processability, are expensive, are harmful substances, and cannot satisfy all purposes.

On the other hand, the development of electrophotography has been further promoted by mechanical engineering and electronic engineering technologies. Not only copying machines used from the beginning, but also printers for electronic computers, microfilm,
In addition to being used for slide film or light printing, it is used in various applications such as color copying, high speed copying, enlargement and reduction copying. As described above, when the use of electrophotography becomes widespread, the required properties for photoconductive materials will also become more sophisticated and diverse.

Further, polyparaphenylene vinylene is a linear conjugated polymer in which phenyl groups and vinylene groups are alternately arranged, and is expected to have photoconductivity because it contains a phenyl group and a conjugated system in its main chain. It can be expected to be applied to electrophotographic photoreceptors. It is known that polyparaphenylene vinylene can be synthesized by the Wittig reaction method or dehydrochlorination method, but the polymers obtained by these synthesis methods have a low degree of polymerization and are insoluble and infusible. It was powdery and could not be formed into a film.

On the other hand, the fact that a polyparaphenylene vinylene structure can be formed by a method of desorbing a sulfonium salt via a polymeric sulfonium salt that is a soluble polymer intermediate is known to be the Journal of polymer science.
ence), A-1,6, PP, 1058 (1968), and US Pat.
32,648 and U.S. Pat. No. 3,706,677 disclose that a polymer sulfonium salt can be cast into a film to form a film-shaped molded product by using the same reaction. After that, JP-A-60-11528 and JP-A-61-16251.
Although the same is also disclosed in Japanese Patent Publication No. 8, the object is a photoconductive composition or a high-strength and high-elasticity film, and no report on an electrophotographic photoreceptor has been made yet.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention Based on the above technical background, the present invention is a linear conjugated polymer in which phenyl groups and vinylene groups are alternately arranged. It is intended to utilize polyparaphenylene vinylene as a photoconductive layer of an electrophotographic photoreceptor.

Means for Solving the Problems An electrophotographic photoreceptor containing polyparaphenylene vinylene for the purpose of achieving the above object is formed in a constitutional unit of a photoconductive layer.

Action The photoconductive layer can form the polyparaphenylene vinylene photoconductive layer from a substantially single material with good workability, and an inexpensive, pollution-free, durable and highly sensitive electrophotographic photoreceptor can be obtained.

Examples Hereinafter, an electrophotographic photosensitive member according to an example of the present invention will be described with reference to the drawings. The figure schematically shows a cross section of one embodiment of the most basic electrophotographic photosensitive member of the present invention.

The electrophotographic photoreceptor shown in the figure has a photoconductive layer 2 containing polyparaphenylene vinylene on a support 1, and the photoconductive layer 2 has a free surface 3 on the one hand.

 Polyparaphenylene vinylene has the formula:

A conjugated polymer obtained by a sulfonium salt decomposition method synthesized from a polymeric sulfonium salt by an elimination reaction of a sulfonium salt is preferably used. The desulfonium salt treatment of the sulfonium salt is preferably performed by heat treatment.

Further, a surface coating layer 4 may be formed on the free surface 3 in order to improve cleaning property, abrasion resistance or corona resistance. Suitable materials for the surface coating layer 4 include Si _x O _1-x , Si _x C _1-x , Si _x N _1-x , Ge _x O _1-x , Ge _x C _1-x , Ge _x N
_{1-x, B x N 1} -x, B x C 1-x, Al x N 1-x (O <x <1), and the like inorganic substances such as a layer containing hydrogen or halogen thereof.

The polymer sulfonium salt can be obtained by condensation polymerization of a P-xylylenedisulfonium salt alone in water or a water-soluble organic solvent such as a mixed solvent of alcohols using an alkali. In order to obtain a sulfonium salt having a high degree of polymerization and to remove unnecessary ions, dialysis treatment with a dialysis membrane is performed. The high molecular weight sulfonium salt thus obtained has a sufficiently large molecular weight, but it is likely to become heterogeneous because it undergoes desulfonium chlorination gradually under conditions such as heat, light, and ultraviolet rays. Therefore, it is preferable to perform the treatment promptly at a relatively low temperature, around room temperature or lower, to obtain a homogeneous polymer sulfonium salt.

Desulfonium saltification of the sulfonium salt can be carried out under various conditions, but heat treatment is preferable. At this time, in order to prevent the oxidation reaction, it is necessary to process in argon, nitrogen, helium gas or in vacuum. Heat treatment is performed at 150 ° C to 350 ° C. The photoconductive layer polyparaphenylene vinylene obtained as described above is used as an electrophotographic photoreceptor with a film thickness of 10 to 40 μm.
The photoconductive layer may be directly formed on the support, or may be attached after forming a film.

(Experimental Example 1) 5 g of P-xylylene-bis (dimethylsulfonium chloride) was dissolved in 80 ml of ion-exchanged water, and 80 ml of 0.2N NaOH aqueous solution was added dropwise at 0 to 5 ° C over 20 minutes, followed by stirring for 40 minutes. . HCl was added as a reaction terminator for neutralization.
The reaction solution was dialyzed for about 5 days using a dialysis membrane. This solution was cast on an Al substrate, dried under reduced pressure at room temperature or below, and
A 20 μm polymeric sulfonium salt film was obtained. This was heat-treated in vacuum at 200 ° C. for about 3 hours.

The photoconductor thus obtained was subjected to a photoconductivity confirmation test with an electrostatic copying paper tester manufactured by Kawaguchi Electric Co., Ltd., and a charging potential of 700 V with a use as an electrophotographic photoconductor, a half-exposure amount of 30 lx- It was found to show a sensitivity of sec.

(Experimental Example 2) Polyparaphenylene vinylene obtained by the same method as in Experimental Example 1 and subjected to heat treatment was set in a CVD apparatus and heated to 180 ° C.
The chamber is once heated to a high vacuum of 1 × 10 ^-5 or less, CH ₄ : 25sccm, SiH ₄ : 25sccm, H ₂ : 50sccm is introduced and discharged, and the surface coating layer Si _x C _{1-x is} formed by plasma CVD. (O <x <
1) was formed about 700Å. When the photoreceptor thus obtained was evaluated in the same manner as in Experimental Example 1, it showed excellent characteristics such as a charging potential of 900 V and a half exposure of 10 lx-sec.

Experimental Example 3 Using 6 g of P-xylylene-bis (diethylenesulfonium bromide), polyparaphenylene vinylene was obtained in the same manner as in Experimental Example 1, and the surface coating layer was laminated in the same manner as in Experimental Example 2. When the photoreceptor thus obtained was wound around a drum and mounted on a copying machine, a clear image could be obtained.

EFFECTS OF THE INVENTION According to the present invention, by forming the photoconductive layer of the electrophotographic photosensitive member with polyparaphenylene vinylene, the photoconductive property can be formed with a single material with good workability, and it is inexpensive, pollution-free, and durable. It is possible to obtain a well-balanced electrophotographic photosensitive member such as high sensitivity.

[Brief description of drawings]

FIG. 1 is a sectional view of an electrophotographic photosensitive member according to one embodiment of the present invention. 1 ... Support, 2 ... Photoconductive layer, 3 ... Free surface.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Koji Akiyama 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Masanori Watanabe 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-60-11528 (JP, A)

Claims (5)

(57) [Claims] 1. An electrophotographic photosensitive member comprising a photoconductive layer made of polyparaphenylene vinylene. 2. The electrophotographic photosensitive material according to claim 1, wherein the photoconductive layer made of polyparaphenylene vinylene is a film obtained by elimination reaction of a sulfonium salt from a polymer sulfonium salt. body. 3. The electrophotographic photosensitive member according to claim 2, wherein sulfur is contained as an impurity. 4. The electrophotographic photosensitive member according to claim 2, which is obtained by heat treatment at 150 ° C. or higher and 350 ° C. or lower in argon, nitrogen, helium gas or in vacuum. 5. The electrophotographic photosensitive member according to claim 2, wherein the free surface has a surface coating layer.