JPS5934298B2 - Photoconductive materials for electrophotography - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photosensitive material using an organic compound as a photoconductor.

The main problem in electrophotographic techniques using organic photoconductors is their low photosensitivity.

Conventionally, polyvinyl heterocyclic compounds represented by poly N-vinylcarbazole, polynuclear aromatic vinyl polymers such as polyvinylanthracene, and other low molecular weight compounds having heterocycles such as oxazole and imidazole nuclei, N, N
Aromatic amine compounds such as , N,N'-tetraphenyl-phenylene diamine, etc. have been used as photoconductive materials for electrophotography, but these alone have not yet been able to provide sufficient photosensitivity. Among these,
In particular, polyvinylcarbazole has been well studied, and various sensitization methods are being considered. Typical examples include a method of adding an electron-accepting substance to polyvinylcarbazole to sensitize it, and a method of introducing various substituents to the carbazole ring.

The present invention relates to a completely new technique of sensitization and desensitization by producing diphenylcarbazylmethane dyes in the presence of poly N-vinylcarbazole derivatives.

The triarylmethane dyes known as sensitizers for poly-N-vinylcarbazole are mainly the following:
It is synthesized by the method. Sandmeyer method: A method using the oxidation of a condensate of an aromatic amine and the corresponding benzene trol compound.

・■、Be)■・-O(■■ 6 +0N<:2 1) Pigmentation 2) Aryl ketone method: A force method in which Michler's ketone and an aromatic amine are condensed with phosphorus oxychloride.

3) Ethyl orthoformate method: Ethyl orthoformate and an aromatic amine are combined with zinc chloride or the photoconductive material for electrophotography of the present invention is applied to method 4) of the above triarylmethane dye synthesis methods. It is then synthesized.

That is, polyvinylcarbazole derivatives are prepared by Vilsmeier and Haac.
k) Introducing a formyl group by a method. The formylated polyvinyl carbazole derivative and aromatic amine derivative obtained in this way are easily synthesized by condensing with a Lewis acid such as zinc chloride, aluminum chloride, or concentrated sulfuric acid, and then oxidizing with perchloric acid or lead peroxide. I can do it. The material according to the present invention is a completely new material that is not dye-sensitized by a formylated poly-N-vinylcarbazole compound and an aniline derivative, nor is it dye-sensitized by an aniline derivative and a Lewis acid. It can be asserted that the N-vinylcarbazole derivative and the aniline derivative are obtained by a unique combination with a Lewis acid. The photoconductive material for electrophotography according to the present invention is not simply dye-sensitized using a low-molecular-weight dye compound, but also uses a formylated poly-N-vinylcarbazole derivative as described in the claims.
This is a completely new photoconductive material for electrophotography in which aniline derivatives are chemically bonded. Raw materials for the formylated poly-N-vinylcarbazole derivative used in the present invention include, for example, poly-N-vinylcarbazole, N-vinylcarbazole copolymer, and brominated poly-N-vinylcarbazole condensed with aluminum chloride. , followed by oxidation with lead peroxide.

4) Benzaldehyde method: Aromatic aldehyde and two molecules of aromatic amine are condensed using zinc chloride or sulfuric acid,
A force method that oxidizes with lead peroxide, etc.

come. Chloroform, dichloroethane, monochlorobenzene, methylene chloride, dioxane, and the like are suitable as the solvent for producing the polymeric diphenylcarbadimelmethane dye according to the present invention.

*A typical manufacturing method of the electrophotographic photoconductor according to the present invention will be described below. Production example (1) Synthesis of formylated poly-N-vinylcarbazole poly-
N-vinylcarbazole (radical polymerized using azobisisobutyronitrile in benzene solution) 1
A solution of 09 dissolved in 40 ml of dimethylformamide was added dropwise over 30 minutes to a mixed solution of 10.59 phosphorus oxychloride and 16 ml of dimethylformamide (internal temperature -2°C) under ice cooling.

Afterwards, stir at the same temperature for 1 hour. Next, raise the internal temperature to 50℃ 4
Stir for an hour. As the reaction progresses, the color of the solution changes from yellowish brown to reddish brown. After the reaction is complete, the reaction solution is poured into 200 g of methanol to form a light brown precipitate. Take this and further precipitate with a chloroform-methanol system to obtain 10.4 g of the target product*1. Elemental analysis values Carbon: 84.1% Hydrogen 5.3% Nitrogen: 6.8% Oxygen 3.8% From this, formium. The conversion rate was found to be approximately 49.5%.

Furthermore, formyl group absorption was clearly observed at 1680 cm −1 from the infrared absorption spectrum. Production example (2) Synthesis of 3-formyl-N-vinylcarbazole and synthesis of poly-3-formyl-N-vinylcarbazole using the same A solution of 19.4 g of N-vinicarbazole dissolved in 15 g of dimethylformamide was poured into ice The mixture was added dropwise over 10 minutes to a cold mixed solution of 19.051 liters of phosphorus oxychloride and 15 grams of dimethylformamide (inner temperature -3°C).

After that, the soil was raised to an internal temperature of 50°C and stirred for about 5 hours. Afterwards, this reaction solution was poured into a large amount of water, neutralized with sodium bicarbonate, and left to stand at room temperature with stirring, and an oily substance crystallized. Take the crystals, wash them with ethanol, and recrystallize them from 100 tons of n-hexane to obtain the desired product (9.8).
Get I.

The N thus obtained has a melting point of 1.025-103.5℃.
- Vinyl-3-formylcarbazole is radically polymerized by a predetermined method to produce formylated poly-N-vinylcarbazole.

In this synthesis, the formylation rate is 100%. Production Example (3) Synthesis of polymeric triarylmethane dye 0.69% of the 100% formylated poly-N-vinylcarbazole obtained in Production Example (2) and 5.09% of dimethylaniline were dissolved in 10ml of acetic acid. Add 1.29 g of zinc chloride into the mixture, raise the internal temperature to 70°C, and heat and stir for 10 hours.

After the reaction is complete, acetic acid and dimethylaniline are removed by steam distillation, and the candy-like blue residue at the bottom of the flask is washed with water, dissolved in methyl ethyl ketone, dried, and iodine 2.0
9 and then 20 d of saturated sodium acetate solution and stirred vigorously at room temperature, a pigmented substance precipitated out.
Take this out, wash it with water, and then wash it with ethanol repeatedly.
A pigmented Max compound 0.62f1 with an absorption maximum of 04=606 nm was obtained.

In order to use the pigmented poly-N-vinylcarbazole obtained in this way as a photoconductive material for electrophotography, it is dissolved in a solvent such as chloroform, methylene chloride, or monochlorobenzene, and then used as a metal plate or a conductive-treated material. It is coated on paper or plastic film to form a photosensitive layer.

It was thus found that the photoconductor has a large sensitizing effect even when used alone. Furthermore, it can withstand practical use even when used in combination with polymeric and low molecular weight organic photoconductive materials such as poly-N-vinylcarbazole and N,N,N',N'-tetrabenzyl-m-phenylenediamine. sell. In addition, if necessary, plasticizers such as dibutyl phthalate and terphenyl,
It is also possible to add chemical sensitizers such as tetracyanoethylene, chloranil, trinitrochlorenone, etc.

The photosensitive layer thus obtained is charged in a dark place according to a conventional method for electrophotography, and a visible image is obtained by imagewise exposure and toner phenomenon. 5. With the photoconductive material for electrophotography of the present invention, clear images can be obtained by either a dry method or a wet method, and all known electrophotographic techniques used in electrofaxing and the like can be used.

Next, the present invention will be explained with reference to Examples, but the present invention 3 is not limited thereto.

Example 1 0.39 g of the pigmented polymeric photoconductive compound of Production Example 3 was dissolved in 3 ml of chloroform and coated on electrically conductive treated paper so that the adhesion amount after drying was 69/i.

This sample was charged in the dark according to a conventional method for electrophotography, and an image was projected using a tungsten lamp light source at an exposure dose of 100 lux seconds. An image with good halftone reproducibility was obtained by liquid development. Further, the potential half-exposure dose of this sample was 31 lux seconds. Example 2 0.02 f1 of 2,4,6-trinitrofluorenone was further added to the formulation of Example 1 and applied to conductive treated paper so that the amount of adhesion after drying was 6.59/d. .

After image exposure, a clear image with high density was obtained by liquid development. The appropriate image projection exposure for this sample was 70 lux seconds. Example 3 5 ml of a chloroform solution containing 0.69% poly-N-vinylcarbazole was added to the formulation of Example 1, and the solution was applied to an aluminum plate so that the amount of adhesion after drying was 7 g/I. .

When this photosensitive plate was charged and exposed in a conventional manner and developed using glass beads as a carrier and carbon black/polystyrene (weight ratio 5:5) toner, a clear image faithful to the original was obtained.

The appropriate image projection exposure for this sample was 75 lux·sec. The spectral sensitivity curve of this light-sensitive material is shown in the drawing.

[Brief explanation of the drawing]

FIG. 1 shows the spectral sensitivity curve of the photosensitive material prepared in Example 3.

Claims (1)

[Scope of Claims] 1. A photoconductive material for electrophotography, the main component of which is a product obtained by reacting a formylated poly-N-vinylcarbazole derivative with an aniline derivative represented by the following general formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, R_1 and R_2 are hydrogen, lower alkyl having 1 to 4 carbon atoms, ▲There are mathematical formulas, chemical formulas, tables, etc.)
R_3 represents chlorine, bromine, lower alkyl, nitro, alkoxy, or hydrogen. )