JPH01142652A - Electrophotographic photoconductive material - Google Patents

Abstract

PURPOSE:To impart photoconductivity for visible rays to an electrophotographic material without adding a charge generating dye to the material by forming the material from a specified rhodanine deriv. and a halogen-contg. polymer. CONSTITUTION:An electrophotographic photoconductive material comprises a rhodanine deriv. expressed by formula I a halogen-contg. polymer. In formula I, R<1> is an (un)substituted alkyl, aralkyl, etc.; R<2> is H or 1-6C lower alkyl, etc. The compd. expressed by formula I has a rhodanine ring and a quinoline ring introduced into a 5-position of the rhodanine ring through an ethanediilidene group, and has absorbing effect for visible rays due to formation of an intramolecular charge transfer chain wherein the rhodanine ring moiety functions as an electron accepting part and the quinoline group moiety functions as an electron donating part. By this constitution, photoconductivity for visible rays is imparted to a material without adding a charge generating dye.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to photoconductive materials in electrophotography.

[Conventional technology]

An example of a practical device using an organic photoconductive compound is an electrophotographic photoreceptor. Conventionally, polyvinylcarbazole (PVCz) has been used to create this electrophotographic photoreceptor.
Research on photoconductive polymers such as these is being widely conducted. All of these molecules have large aromatic rings in the main chain or side chain.
It has a heterocyclic ring, and photoconductivity is obtained by the movement of carriers generated by the dissociation of excitons excited by ultraviolet light using a series of π electron systems. In general, -
A method is used in which a polymer photoconductive compound such as VCZ or a low molecular photoconductive compound such as a hydrazone derivative is combined with a carrier-generating pigment to sensitize it to the visible light range.

[Problem that the invention seeks to solve]

Conventional photoconductive polymers such as P V Cz do not exhibit conductivity to visible light, and low-molecular photoconductive compounds such as hydrazone derivatives do not generate carriers in visible light, so they are suitable as photoreceptors for electrophotography. When used, they cannot be used alone and require the addition of dyes or pigments that are sensitive or sensitizing to visible light.

Therefore, both of these methods require dispersion of the pigment into the binder polymer. It is difficult to uniformly disperse a pigment that is insoluble in a solvent in a binder polymer, and there are also problems with the stability of the dispersion, which shortens the life of the coating solution.

Furthermore, since pigments are aggregates, differences in the conditions of the pigment manufacturing process greatly affect the electrophotographic characteristics of the photoreceptor produced. To solve this problem, there were many technical issues in controlling the physical properties of pigments.

Therefore, an object of the present invention is to provide a photoconductive material for electrophotography that exhibits photoconductivity in visible light without the need to add charge-generating pigments.

[Means and effects for solving the problems] In order to solve the above problems, the photoconductive material for electrophotography of the present invention has the following features:
The following - Substitute (1) (R' represents a substituted or unsubstituted alkyl, aralkyl, aryl, amino group, R2 is hydrogen, carbon number 1
~6 lower alkyl groups, substituted or unsubstituted aryl groups, and hydroxyl groups. ) and a halogen-containing polymer.

The compound represented by the general formula (r) used in the present invention is characterized by having a rhodanine ring and a quinoline group introduced at the 5-position of the rhodanine ring via a 2-butyldiylidene group. Absorption of visible light is due to the formation of an intramolecular charge-transfer chain in which the rhodanine ring serves as an electron acceptor and the quinoline group serves as an electron donor. In other words, the π electrons that were delocalized in the electron donor in the ground state are in the group r=CH=C
The present invention absorbs light energy and produces color when it transfers to the vacant orbital of the electron acceptor through H-CH=J.2 The present invention has an ethanediilidene group in the ortho position of the quinoline group, so the electron of the electron donor is The donor property increases, and as a result, light absorption appears in a relatively long wavelength region of the visible light region. Moreover, the photoconductivity is due to the above-mentioned large conjugated system. The photoconductivity of the compound represented by the general formula (1) as described above is significantly exhibited by using a halogen-containing polymer as the binder polymer. In other words, in a polymer having a strong electron-withdrawing substituent such as a halogen, polarization occurs near the substituent, and the electric field generated thereby promotes the above-mentioned intramolecular charge transfer of the compound represented by (1). considered to be a thing.

In the rhodanine compound represented by the above-mentioned -Kakuju CI), examples of the alkyl group that may have a substituent among R1 include lower alkyl groups such as methyl, ethyl, propyl 1, isopropyl, butyl isobutyl, tert-butyl, pentyl, and hexyl group. Examples include groups. Substituents for the above alkyl group include carboxyl group, aldehyde group, hydroxyl group,
An example is a halogen atom.

Examples of aralkyl groups that may have substituents include benzyl, phenylethyl, and naphthylmethyl groups. Substituents for the aralkyl group include, in addition to the alkyl group in R1, alkoxy groups such as methoxy, ethoxy, and propoxy groups; amino groups; alkylamino groups such as dimethylamino, diethylamino, and dipropylamino groups;
Examples include halogen atoms.

Examples of the aryl group that may have a substituent include phenyl, naphthyl, anthryl, phenanthryl, fluorenyl, 1-pyrenyl, etc., and examples of the substituent of the aryl group include the substituents in the aralkyl group mentioned above. .

As a substituent for the amino group, the alkyl group in R1 above is exemplified.

In addition, among R2, the alkyl group is methyl, ethyl,
propyl, isopropyl, butyl isobutyl, tert
-Lower alkyl groups such as butyl, pentyl, and hexyl groups are exemplified.

Examples of the aryl group include the aryl group for R1 above.

Specific examples of the rhodanine compound represented by the above-mentioned -rhodanine (r) include those having the following structural formula.

The rhodanine compound represented by the above-mentioned -rhodanine (r) of the present invention can be synthesized by various methods, for example, by the following reaction formula.

(In the formula, R1 and R2 are the same as above.) That is, the compound (1) of the present invention has the above-mentioned
) and the above -C formula (3)
It can be obtained by reacting 2-β-acetanilide vinylquinoline alkyl iodide represented by in alcohol.

Examples of the halogen-containing polymer include polyvinyl chloride resin, polyvinylidene chloride resin, polyfluoroethylene resin, polychloromethylstyrene, etc.
Examples include copolymers such as -1 Usushi, vinyl chloride-vinyl acetate copolymer, and chloromethylated polystyrene-styrene copolymer.

〔Example〕

Hereinafter, the present invention will be described in more detail based on Examples.

Tanjiku San Etori Jba Compound of Synthesis Example 1 below (hereinafter referred to as Compound 1), Compound of Synthesis Example 2 (hereinafter referred to as Compound 2), Synthesis Example 3
A compound (hereinafter referred to as compound 3) was used.

Synthesis Example 1 Synthesis of 3-carboxymethyl-5-(2-(1-ethylquinoline)dimethine) rhodanine 19.1 g of 3-carboxymethyl rhodanine and 46.6 g of 2-β-acetanilide vinylquinoline ethiodide , 12.1 g of triethylamine was refluxed in ethanol for 930 minutes, and the product was recrystallized from pyridine to obtain the title compound (compound 1).
I got it. (Yield 50%).

Synthesis Example 2 Synthesis of 3-amino-5-(2-(1-ethylquinoline)dimethine)rhodanine The above synthesis example uses 3-aminorhodanine in place of 3-carboxymethylrhodanine in Synthesis Example 1 above. The title compound (compound 2) was obtained in the same manner as in 1 (yield 44%).
.

Synthesis Example 3 Synthesis of 3-phenyl-5-(2-(1-methylgynoline)dimethine]rhodanine Using 3-phenylrhodanine instead of 3-carboxymethylrhodanine in Synthesis Example 1 above, 2-β-acetanilide vinyl The title compound (compound 3) was obtained in the same manner as in Synthesis Example 1 above, using 2-β-acetanilide vinylquinoline methiodide instead of quinoline ethiodide (
yield 51%).

Binder Polymer As the binder polymer, polyvinylidene chloride (trade name "Saran", manufactured by Asahi Kasei Co., Ltd.) was used, and for comparison, polycarbonate resin (trade name "Panrai 1-L-1250J, manufactured by Ondai Kasei Co., Ltd.) was used.

50 parts by weight of each rhodanine derivative described above and 100 parts by weight of polyvinylidene chloride described above were dissolved in tetrahydrofuran, coated on aluminum foil using a doctor blade, dried at 100°C for 30 minutes, An electrophotographic photoreceptor was created.

For comparison, an electrophotographic photoreceptor was prepared in the same manner as the above electrophotographic photoreceptor except that polycarbonate resin was used instead of polyvinylidene chloride.

While conventional photoreceptors in which charge-generating pigments are dispersed in binder polymers are opaque, the photoreceptors created are transparent and can efficiently absorb irradiated light. This is because the pigment is dispersed in the polymer as an aggregate, whereas the rhodanine derivative of the present invention is molecularly dispersed in the polymer.

In order to examine the charging characteristics and photosensitivity characteristics of the electrophotographic photoreceptor, corona discharge was performed for 5 seconds at +6.0 kV using an electrostatic copying paper tester (manufactured by Kawaguchi Electric Co., Ltd., model 5P-428). Each photoreceptor is negatively charged, and the surface potential at this time (■.

) was measured. Then, using a tungsten lamp,
Adjust the illuminance on the surface of the photoreceptor to 201ux, expose it with a tungsten lamp, find the time until the surface potential V0 becomes 1/2, and calculate the half-reduction exposure 'ft.
E + y□ was calculated.

Table 1 shows the measurement results of the charging characteristics and photosensitive characteristics of each photoreceptor.

Table 1 PC: Polycarbohydrate + 1d fat As shown in Table 1, the photoreceptor made of polyvinylidene chloride containing compounds 1 to 3 had excellent charging properties, had a small half-decrease exposure amount, and exhibited good electrophotographic properties. .

On the other hand, when a polycarbonate resin containing no halogen was used as the binder polymer, the half-decrease exposure amount was extremely large, and the resin could not be used for electrophotography.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a photoconductive material for electrophotography that exhibits photoconductivity in visible light without the need to add a charge-generating pigment.

Claims (1)

[Claims] The following general formula▲ includes numerical formulas, chemical formulas, tables, etc.▼ (R^1 represents substituted or unsubstituted alkyl, aralkyl, aryl, or amino group, and R^2 represents hydrogen or the number of carbon atoms 1 to 6 lower alkyl groups, substituted or unsubstituted aryl groups, and hydroxyl groups.) A photoconductive material for electrophotography comprising a rhodanine derivative represented by the following formula and a halogen-containing polymer.