JPS62267757A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To increase the sensitivity of a sensitive body and to reduce the dark attenuation by forming a photosensitive layer contg. a specified squarylium pigment. CONSTITUTION:A squarylium pigment represented by the formula is used in the electrostatic charge generating layer of a sensitive body. In the formula, Ar1 is phenyl or substituted phenyl having 1-6C straight chain alkyl, hydroxyl, 1-4C alkoxy, halogen, nitro, cyano, carboxyl or the like and each of Ar2 and Ar3 is phenylene or substituted phenylene having halogen, carboxyl, hydroxyl, methyl or trifluoromethyl. Thus, a sensitive body having spectral sensitivity over the visible region and the near infrared region, high sensitivity, superior electrostatic chargeability and dark decay is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor used in an electrophotographic process. More specifically, the present invention is based on a light guide of 1 ton.
This invention relates to an electrophotographic photoreceptor lc containing a square lyllium pigment in nitrogen.

[Conventional technology]

Conventionally, inorganic photosensitive materials such as amorphous selenium, selenium alloys, cadmium sulfide, and zinc oxide, as well as organic photosensitive materials such as polyvinyl carbazole and polyvinyl carbazole derivatives, have been widely used as electrophotographic photoreceptors. There is.

It is well known that amorphous selenium or selenium alloys have extremely attractive properties as photoreceptors for electrophotography and are used in practical applications. but.

Its production requires a complicated step of vapor deposition, and the vapor-deposited film thus produced has the drawback of not being flexible. When zinc oxide is used, it is used as a dispersed photosensitive material in which zinc oxide is dispersed in a resin, but such photosensitive materials have a drawback in mechanical strength and cannot withstand repeated use as is.

Kashiisomoto: Polyvinylcarbazole, which is widely known as a conductive material, has excellent advantages in terms of transparency, film-forming properties, and flexibility, but polyvinylcarbazole itself does not have sensitivity in the visible light range. Therefore, it cannot be put to practical use as it is, and therefore various sensitization methods have been devised.However, when polyvinylcarbazole is spectrally sensitized using a dye sensitizer, the spectral sensitivity range is within the visible light range. However, it still has the drawback of not being able to obtain sufficient sensitivity as a photoreceptor for electrophotography and suffers from severe photofatigue.Also, when chemically sensitized using an electron-accepting compound,
Although photoreceptors with sufficient sensitivity have been developed as photoreceptors for electrophotography, and some of them have been put into practical use, problems still remain in terms of mechanical strength, lifespan, and the like.

It has been reported that a laminated photoreceptor having a charge generation layer and a charge transport layer has electrical properties superior to those of conventional photoreceptors. 1 used for these photoreceptors! Materials that generate chemicals include bisazos, trisazos, phthalocyanines,
Viryliums, squarelilliums, etc. are known.
Phthalocyanines, trisazos, and squareyliums have been reported to have sensitivity from the visible region to the near-infrared region.

However, phthalocyanines have the drawbacks of spectral sensitivity biased towards long wavelengths and poor red color reproducibility, while trisazos have excellent electrical properties and sufficient sensitivity.

In addition, although the square +31J umium compound shown in JP-A-49-105536 has relatively high sensitivity, it has drawbacks such as chargeability and dark decay, and it is difficult to achieve both high sensitivity and low dark decay. not present.

[Problem that the invention seeks to solve]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks, and to provide an electrophotographic photoreceptor having spectral sensitivity from the visible region to the near-infrared region, high sensitivity, and excellent electrical properties.

[Means and effects for solving the problems] The objects of the present invention can be achieved by an electrophotographic photoreceptor using an asymmetric square lylium compound represented by the following general formula (1) as a photosensitive material.

〇- 〇- In general formula (1), Arl is a phenyl group, or carbon &2
1 to 6 linear alkyl groups, hydroxyl groups, alkoxycarbonyl groups having 1 to 4 carbon atoms, halogen atoms, nitro groups, cyano groups, carboxyl groups, alkoxycarbonyl groups having 1 to 4 carbon atoms,
or a trifluoromethyl group, representing a phenyl group substituted with 4;
, a carboxyl group, a halogen atom, and a trifluoromethyl group (both represent a phenylene group substituted with one substituent).

Specific examples of the square IJ compound represented by the general formula (1) are shown below in terms of structural formulas. In the formula, Me represents a methyl group.

The square aryllium pigment represented by the general formula (I) can be used in a Seiko photographic photoreceptor having a multilayer structure.

That is, in an electrophotographic photoreceptor 1 including a photosensitive layer with a two-layer structure consisting of a 1ttr generation layer and a 4M transport layer, a charge generation layer containing a square IJium pigment and a known i! By providing a charge transport layer, it is possible to obtain a photoreceptor with high sensitivity and improved electrical properties such as chargeability and dark decay.

As the charge transport layer, N-methyl-N-phenylhydrazino-3-methylidene-9-ethylcarbazole, p-
Diethylaminobenzaldehyde-N,N'-diphenylhydrazone, p-diethylaminobenzaldehyde-
Hydrazones such as N-α-nafdel-N-phenylhydrazone, 1-phenyl-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[quinolyl(2))-3-(p Pyrazolines such as -diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, oxazole compounds such as 2-(p-diethylaminostyryl)-6-dinithylaminobenzoquipzole, bis(4-diethylamino-2 -methylphenyl)-triarylmethane compounds such as phenylmethane, N,N'-diphenyl-N
, N'-bis-(3-methylphenyl)-(1,1'-
Biphenyl]-4,4'-diamine and other diamine-based compounds contained in the binder resin, or poly-IJ
-N-vinylcarbazole, polyvinylanthracene, and other light-guiding 1u polymers are used.

To explain the charging of the electrophotographic photoreceptor having a two-layer structure according to the present invention, as shown in FIGS.
and 1 containing a charge transport substance! A photosensitive layer 4 made of a laminate with a cargo transport layer 3 is provided. Charge generation layer 2 and charge transport layer 3
The stacking order of is arbitrary.

The charge generation layer may be formed by using the square lyllium pigment alone, but it can also be formed by using it in combination with a binder resin.

The ratio of pigment to binder resin is to:1il1%
90% by weight, preferably 10% to 50% by weight.

Methods for forming a charge generation layer using a square aryllium pigment alone without using a binder resin include a solvent 2 cloth method and a vacuum evaporation method.

The thickness of the charge generation layer is 0.1 to 3 μm, preferably 0.2 to 1 μm.
μ.

When dispersing in the binder, the pigment is ground and used, but the grinding method is 5PEX MILL, ball mill, R
A known method such as ED ogvIt (trade name) can be used.

The binder of the charge generation layer may or may not itself have photoconductivity. A photoconductive binder and a photoconductive polymer such as polyvinylcarbazole, polyvinylcarbazole derivatives, polyvinylnaphthalene, polyvinylanthracene, polyvinylpyrene, or other organic polymers having photoconductive transport ability, IJ lux agent, etc. be.

Furthermore, a known insulating resin without light guide ta can also be used as the binder. Known insulating resins include polystyrene, polyester, polyvinyltriene, polyvinylanisole, polychlorostyrene, polyvinyl butyral, polyvinyl acetate, polyvinylbutyl methacrylate, copolystyrene-butadiene,
Polysulfone, copolystyrene-methyl methacrylate, polycarbonate, etc. can be used.

At this time, in order to further improve the mechanical strength of the resulting photoreceptor, plasticizers can be used in the same way as general polymer materials. Examples of plasticizers include chlorinated paraffin, chlorinated biphenyl, and phosphate. type plasticizers, phthalate type plasticizers, etc. can be used, and O
~10% by weight is added without deteriorating the sensitivity or electrical properties of the photoreceptor (it is possible to further improve its mechanical strength).
It is E.

A protective layer or a photosensitive layer 4 and a conductive support 1 are provided on the photosensitive layer 4.
An intermediate layer may be placed in between. The protective layer may be one in which a residual oxide is dispersed in a resin, or one in which an electron-accepting compound is added to a resin. Examples of the intermediate layer include metal oxides such as aluminum oxide, acrylic resins, phenolic resins, polyester resins, polyurethanes, and the like.

A binder in which square aryllium pigment is dispersed is applied onto a conductive support. Coating methods include a dipping method, a spray method, a bar coater method, and an applicator method, and a good photosensitive layer can be formed by any of these methods.

As the conductive support, metal, paper treated with conductivity, a polymer film having a conductive layer, glass, etc. can be used.

The electrophotographic photoreceptor of the present invention can be widely used not only in copying machines but also in semiconductor laser printers and the like.

Next, the present invention will be explained from Example 1.

〔Example〕

Example 1 1 part by weight of the compound of structural formula &1 of the specific example, 1 part by weight of polyester resin (manufactured by DuPont, Atohetsusib 49000), and 10 parts by weight of tetrahydro 7 run were added, and the mixture was ground and mixed in a ball mill for 4 hours. The dispersion was coated with aluminum using a bar coater to form a polyester film [
Made by Toshi, coated on Metal Me (registered trademark) and heated at 70°C.
The mixture was dried for 5 hours to form a charge generation layer with a thickness of 1 μm.

On this charge generation layer, N,N'-diphenyl-N,N'
-Bis-(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine 1 part by weight, polycarbonate resin [manufactured by Kijin, Panlite (registered trademark)] 11 parts by weight Tetrahydrofuran 10 parts by weight A uniform @ solution was applied using an applicator and dried at 70'Q for 16 hours to form a charge transport layer with a thickness of 22 μm, thereby producing a photoreceptor.

Next, using an electrostatic copying paper testing device (manufactured by Kawaguchi Electric, Electrostatic Paper Analyzer 5P-428), a -6KV corona discharge was applied to negatively charge the paper, and then the paper was negatively charged.
Leave it in the dark for 2 seconds, then use a tungsten lamp,
The dark photosensitive layer is irradiated with light so that the surface illuminance is 10 lux, and the surface potential after the number of dark places is VD.
The exposure amount E1/2, which is 172, was determined. The results are: initial band 'dt potential V0 = -1010'/, potential after being left in the dark for 2 seconds vDpp: -950v %E 1/2
= 2.9 lux·sec, residual potential RP=OV.

In addition, the following measurements were performed to demonstrate that the material has extremely high sensitivity to long wavelength light. After charging the above photoconductor by performing corona discharge in a dark place, it was separated into 800 nm and 1 μW using a monochromator.
/- monochromatic light was irradiated onto the photoreceptor. Then, the time until the surface potential reached 172 was measured, and the exposure amount was determined.

The result was 14.5 erg/-.

Examples 2 to 10 (Power of square lylium pigment in Example 11 and 41)
Instead, as shown in Table 1, &2.3.4.5.6.11.
12.17.19 Photoreceptors were prepared and evaluated in the same manner as in Example 1, except that the square aryllium pigments of Examples 2 to 10 were used, and the results are shown in Table 1.

Table 1 [Effects of the Invention] The present invention provides an electrophotographic photoreceptor having a photosensitive layer containing a square aryllium compound that has spectral sensitivity from the visible region to the near-infrared region and has high sensitivity and excellent electrical properties. It has excellent electrical properties such as chargeability and dark decay, and can be widely used not only in copying machines but also in semiconductor laser printers and the like.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of examples of the electrophotographic photoreceptor of the present invention. Symbols in the figure: 1... Conductive support; 2... Charge generation layer; 3...
Charge transport layer; 4... Photosensitive layer. Figure 1 Figure 2

Claims (1)

[Claims] General formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, Ar_1 is a phenyl group, a linear alkyl group having 1 to 6 carbon atoms, a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms] , represents a phenyl group substituted with a halogen atom, a nitro group, a cyano group, a carboxyl group, an alkoxycarbonyl group having 1 to 4 carbon atoms, or a trifluoromethyl group, and Ar_2 and Ar_3 are not the same and each represents a phenylene group. , or a phenylene group substituted with at least one substituent selected from a hydroxyl group, a methyl group, a carboxyl group, a halogen atom, and a trifluoromethyl group. ] An electrophotographic photoreceptor characterized by having a photosensitive layer containing a squarerium pigment represented by the following.