JPH02131245A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the org. photosensitive body which is of a positive charge system and has high sensitivity and excellent durability by providing a charge transfer layer contg. high-polymer materials consisting of a specific molecular structure. CONSTITUTION:The high polymers expressed by the formula I are used as the org. photoconductor material by the positive charge system. In the formula I, R denotes a bivalent cyclic substituent contg. a pi electron conjugation system and n denotes >=2 integer. All these high polymers have the high electron transfer power and the characteristics as the excellent photosensitive body are attained by combining the high polymers as a charge transfer material for positive charge with a suitable CG material (charge generating material). Since the high polymers have the film formability, the CT layer (charge transfer layer) can be formed without requiring a binder resin. Since the photosensitive body operates in the positive charge system in this way, the generation of the ozone to deteriorate the characteristics of the photosensitive body is substantially prevented and since the high polymers have the high thermal stability, the CT layer having the excellent durability is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrophotographic photoreceptor, and more particularly, to an electrophotographic photoreceptor having a charge transfer layer containing a polymeric material having a specific molecular structure and suitable for positive charging. Regarding the body.

Conventional technology Compared to inorganic photoreceptors, organic photoreceptors (abbreviated as OPC) are capable of synthesizing material that is highly sensitive to various wavelengths through molecular design, are non-polluting, have excellent productivity and economy, and are inexpensive. It has the following characteristics and is currently undergoing active research and development. In addition, remarkable improvements have been made in terms of durability and sensitivity, which were conventionally considered problems of organic photoreceptors, and some of these improvements have been put into practical use, and they are now becoming the mainstay of photoreceptors for electrophotography.

OPC is usually used with a double layer structure of a charge generation layer (abbreviated as CGL) and a charge transfer layer (abbreviated as CTL), and its sensitivity is improved. Various organic materials such as berylene compounds, phthalocyanine compounds, thiapyrylium compounds, anthanthrone compounds, squarylium compounds, and pisazo compounds have been studied as materials for use in CGLs.

On the other hand, various hydrazone-based compounds, oxazole-based compounds, triphenylmethane-based compounds, arylamine-based compounds, and the like have been developed as materials (CTM) used for CTL.

Furthermore, in recent years there has been an increasing demand for the use of these organic photoreceptors in the near-infrared region, which corresponds to semiconductor laser light (780-830 nm), as photoreceptors for digital recording in laser printers and other devices. Organic photoreceptors with sensitive characteristics are being actively developed. Organic photoreceptors are advantageous in terms of sensitivity than inorganic photoreceptors as photoreceptors in such areas, and various lid cyanine pigments, trisazo pigments, azulenium dyes, and the like have been developed as charge generating materials (CGM).

These materials are formed on a substrate such as a drum or belt by a relatively simple method of coating together with a binder polymer. Generally, in a double layer structure, the CG layer is coated to a thickness of several microns in order to increase sensitivity, while the CT layer is coated to a thickness of several tens of microns. At this time, its strength, printing durability,
For these reasons, the CG layer is usually formed on the substrate side, and the CT layer is usually formed on the surface side. In such a configuration, CT
Since only those in which M is activated by the movement of holes have been put into practical use, the double layer photoreceptor is of a negative charging type.

Problems to be Solved by the Invention In such a negative charging system, ozone is generated due to negative charges. Such ozone not only accelerates the deterioration of the photoreceptor, but is also harmful to the human body, and is currently a major problem in device formation.

In order to solve these problems, positive charging systems are being actively studied. The first method is to reverse the above-mentioned CT layer and CG layer, placing the CT layer on the substrate side and the CG layer on the surface. However, this attempt was not successful because it was difficult to increase the thickness of the CG layer, making it impossible to improve the printing durability of the paper.

The second method is to develop CT materials that work by transferring electrons. This method is the most desirable method because a positive charging system can be realized with the current two-layer structure. However, at present, no CT material has been developed that has excellent performance and works in electron transfer.

An object of the present invention is to provide a novel high-performance organic photoreceptor that operates through electron transfer, and in particular, to provide an organic photoreceptor that is positively charged and has high sensitivity and excellent durability.

Means to solve the problem In order to solve the above problems, we are currently using OPC.
We developed a new polymer OPC to replace the low-molecular OPC material that is the mainstream material.

As a result, they discovered a high-performance polymeric organic photoreceptor for positive charging that operates through electron transfer, and accomplished the present invention.

Therefore, the organic photoconductor according to the present invention has the following general formula: +R-CH=CH+ n [where R is a divalent cyclic substituent containing a π-electron conjugated system,
n represents an integer of 2 or more] is used.

Furthermore, the polymers mentioned above include polyparaphenylene vinylene (abbreviated as PP■), polythenylene vinylene (PTh■
(abbreviated as), polynaphthalene vinylene (abbreviated as PNa■)
, polymethoxy7-paraphenylene vinylene (abbreviated as PMPV), polydimethoxyphenylene vinylene (PDMPV)
It is preferable that the mosquito be at least one species selected from the group consisting of mosquitoes.

Function All of the above-mentioned polymers have high electron transfer ability, and conventional suitable CG
By combining it with other materials, it is possible to achieve excellent properties as a photoreceptor. However, since these polymers have film-forming ability, it is possible to form a CT layer without requiring a binder resin. Since these polymers operate using a positive charging system, there is almost no ozone generation that can cause deterioration of photoreceptor characteristics, and they also have high thermal stability, making it possible to form a CT layer with excellent durability. I can do it.

Example This invention will be explained in detail below.

First, the conductive support serving as the substrate of the organic photoconductive layer is not particularly limited, and can be appropriately selected depending on the intended use. Specifically, metals such as aluminum, glass, paper, or plastics on which a conductive layer is formed by a method such as metal vapor deposition are preferably used. Moreover, it can take various shapes such as a drum shape, a belt shape, and a sheet shape.

Next, the organic photoconductor used in this invention is represented by the general formula; There are no particular limitations as long as it is a cyclic substituent.

Examples of the cyclic conjugated substituent include various aromatic hydrocarbons and heterocyclic compounds. Specifically, -R- can be exemplified by @ in lJ00. Of course, these polymeric organic photoconductors may be used alone or in combination.

Among the above-mentioned various polymer photoconductors, -R is represented by (1) to (5) in order, PPV, PThV, PN.
It is preferable to use five types: aV, PMPV, and PDMPV. These five types of polymers have particularly high sensitivity to positive charging methods and are excellent in stability.

These alkylvinylene compounds are generally synthesized by the following reaction, although there are no particular limitations on the synthesis method and the method for forming the photoconductive layer.

-XR 2S"CH.RCHzS"R'. X-(A) NaOH Heating X-S"R"2 (B) (C) Water is generally used as a solvent, and sometimes a methanol solvent is also used. Film formation is a precursor of polymers (B)
This is done by casting on the CG layer and heat-treating the cast film. Note that specific methods for synthesizing these polymers are described in the following documents.

('D U.S. Patent No. 3,401,152 Specification 1■ U.S. Patent No. 3,706,677 ■ I. Murase et al.
Polymer Communication 1 7
r communication) 25, 327
(1984) ■ S. Antoun et al., Polymer Bulletin
15, 181 ■ S, Ant, > - N (S.
Antoun et al., Journal of Polymer Science Sea Polymer Letters (J. Polymer
Science, C, Polymer Lett
ers) 24, 503 (1986)■
K-Y.Jan Synthetic Metals
22, ■ K- Y. Jen
), Journal Op Chemical Society
Chemical communications (J. Chem.
SocChem. Commun. ) 1987.
309 The polymeric photoconductive layer of the present invention thus formed is used for positive charging, but in that case it is necessary to combine it with a conventionally used CG material. In this case, it is possible to have a double-layer structure in which the CG layer is placed on the substrate side and the polymer layer according to the present invention is provided thereon, or a CG material is added to the polymer photoconductor to form a composite.
It can also have a single layer structure.

The following compound Q316 can be exemplified as a CGL material used for such a purpose. Among them, the various phthalocyanines shown in Q3α are preferably used for the purpose of the present invention, and X-type and τ-type phthalocyanines are particularly suitable.

α phrase 0Q Q3 a4 CH3 Y=H, OH, CH. Since the polymeric organic photoconductor of the present invention exhibits excellent properties in a positive charging system, it can be used with various hydrazone-based compounds, oxazole-based compounds, triphenylmethane-based compounds, etc., which are commonly used in negative charging systems. Adding materials often exhibits a decrease in positive charging properties. Therefore, the polymer organic photoreceptor of the present invention cannot be used as a composite with a negatively charged CT material. However, the polymer organic photoreceptor of the present invention and CT
Of course, it is possible to use a composite with a material in a negatively charged manner.

Furthermore, although the polymeric organic photoconductor of the present invention forms an excellent film by itself, it can be combined with various binder polymers to improve its strength and adhesion to the CG layer.

The electrophotographic photoreceptor according to the present invention described above is
For example, it can be used in various recording systems such as copying machines, printers, and facsimile machines, and its uses are not limited in any way. Note that the electrophotographic photoreceptor according to the present invention is not limited to the above examples, but may further include, for example, forming a surface protection layer of an insulating resin on the organic photoreceptor layer as necessary.
It is also possible to provide a pronoking layer between the CG layer and the substrate.

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Example 1 X-type metal-free phthalocyanine dispersed in dioxane solvent [
Manufactured by Inu Nippon Ink Chemical Industry ■, Fast Genple (F
astogen Blue) 8120B)7/
A CG layer (thickness: 2 to 4 μm) was formed by coating on the L/Midram.

Next, a methanol solution of a PPV precursor synthesized by the method described in the above-mentioned document (2) was applied onto the CG layer by the dispersion method to form a coating film with a thickness of 15 to 20 μm. The coating film was heat treated in vacuum at 200°C for 1 hour to convert it to PPV,
A photoreceptor with a two-layer structure was obtained.

The photosensitive characteristics of the photoreceptor obtained in this way were evaluated using EP manufactured by Kawaguchi Electric.
Using a paper analyzer model A-8100, white light from tungsten was irradiated to measure the photosensitivity (half exposure amount) due to positive charging. Its sensitivity is 0. 5 lux
- sec. Furthermore, the photosensitivity after 1000 repeated tests was also measured at the same end. Its sensitivity is 0.6lux
- sec, and almost no change in characteristics was observed.

Example 2 PTh■, PN instead of PPVO in the same manner as Example 1
Create aV, PMPV, PDMPV coatings on the CG layer,
The photosensitive characteristics due to positive charging were measured. In addition, PThV
The synthesis of PNaV is in the literature, and the synthesis of PNaV is in the literature ■, PMPV,
The synthesis of PDMPV was carried out with reference to the methods in the literature ①, ②, ②, ②. Photosensitivity due to white light (half exposure amount) p'rh
v:o. slux-sec, PN a V: Q,
81ux-sec1PDMPV: 1, 3 lux -
Sec. In addition, the characteristics after 1000 times repeated test are p'rhv: 0.91ux-sec, p
NaV: o,slux-secSPMPV: 1.
21ux-sec, PDMP V: 1. 4 1u
x-sec, indicating excellent letter stability.

Example 3 R-type metal-free cap cyanine [manufactured by Toyo Ink Mfg. ■, Rio 7 O] 7 was used as a CG material in the same manner as in Example 1.
(Liophoton) TPH 278), ε-type copper phthalonanine (manufactured by Toyo Ink Mfg. ■, Liophoton ERPC), perylene compound aQSQη [commercially available], AICI-Futakuchi cyanine,
InCI-phthalonanine, T10-phthalonocyanine, Mg-phthalonanine, thiapyrylium compound α-teng,
Diazo compound (c), squarylium compound α1, (c), triazo compound (1), azulenium compound (a)
[Each was synthesized according to the method described in the literature] to create a CG layer, and a photoreceptor having a double layer structure with PPV was created. The photosensitive characteristics (half exposure amount) due to positive charging of each were as follows.

τ-type phthalocyanine: 0.7 lux − sec,
ε type phthalocyanine 7 = 7: 0, 7 1ux-s
ec, peri-L/7 compound αd:l, Qlux-se
c, Peri L/7 compound θ + 1, 5 lux −
secSAICI7月077=n: 1.11ux-s
ec, InCI-;y20'7=7:1,
1! 11X- sec1TiO- 7 Talosia = 7
: 0.9 lux-sec, Mg-7: 1.21 ux-sec, diazo compound (t): 1,
4 lux - sec, squarylium compound Ql
: 1, 2 lux-sec, squarylium compound 21) : 1.4 lux-sec, trisazo compound ep: 1, 2 lux-sec,
Azulenium compound 122): Q8lux-s
ec0 Also, the characteristics after 1000 repeated charging tests were as follows, showing excellent stability.

τ type lid cyanine: Q, 8lux - sec,
ε-type Phthalosi 7=N: Q. 81 ux-sec, perylene compound ae: i. olux-sec, helicopter L/
Compound α7): l. 7 lux-seeS
AICI-lid 7=7: 1.21ux-se
c, InCI- Lid 7= N: 1. 2
lux-sec, TiO-7 talocyan: 0
．． 9 Iux- sec, Mg- 7 talosia = 7
: 1. 3 lux - sec, diazo compound (1
8): 1,6 lux-sec, squarylium compound Ql: 1.5 lux-sec, squarylium compound Q]): 1,5 lux-se
c, trisazo compound @J: 1, 4 lux
- see, azulenium compound @: 1, 1
lux 1sec0 or more, Examples 1 and 2. As shown in No. 3, all of the photoreceptors of Examples had very high sensitivity, and their characteristics hardly changed even after repeated tests, indicating that they were also excellent in stability.

Effects of the Invention As described above, since the electrophotographic photoreceptor according to the present invention uses a polymer photoconductor based on electron transfer, it can be charged using a positive charge compared to conventional photoreceptors. It has high sensitivity and excellent stability, and is expected to be applied to various recording devices as a positive charging electrophotographic photoreceptor with further improved performance.

Claims (3)

[Claims] (1) As an organic photoconductor material using a positive charging method, the following general formula; ▲ There are mathematical formulas, chemical formulas, tables, etc.
represents an integer of 2 or more]. (2) A photoreceptor for electrophotography, characterized in that the polymer layer for an organic photoreceptor according to claim 1 is formed on a charge generation layer provided on a conductive substrate. (3) The polymer for organic photoconductor is selected from the group consisting of polyparaphenylene vinylene, polythienylene vinylene, polynaphthalene vinylene, polymethoxyparaphenylene vinylene, and poly-2,5-dimethoxyparaphenylene vinylene. The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor comprises at least one type of: