DE2401115A1 - LIGHT SENSITIVE PLATE AND LIGHT SENSITIVE MATERIAL FOR ELECTROPHOTOGRAPHY - Google Patents

Description

PATENT OFFICE TlEDTKE - BüHLING "

TEL. (089) 53 96 53-56 TELEX: 524845 tipat CABLE ADDRESS: Garmaniapatent Munich

A H V I f I

8000 Munich 2

Bavariaring 4

Postfach 202403> ¹ O. January 1974

B 5791

Canon Kabushiki Kaisha
Tokyo, Japan

Photosensitive plate and photosensitive material for

electrophotography

The invention relates to photosensitive materials and photosensitive plates for electrophotography. In particular it concerns the addition of an electron acceptor compound for the purpose of sensitizing an organic, photoconductive material.

It is known that a number of organic compounds can be used in the manufacture of a photoconductive body for electrophotography Is used. While this organic

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Deutsche Bank (Munich) Account 51/61 070 Dresdner Bank (Munich) Account 3939 844 Postal check (Munich) account 670 43-804

Compounds in comparison to inorganic photoconductive compounds show several advantages, they still have some Cons that should be eliminated. A serious disadvantage is that they are extremely weakly sensitive are and their maximum of the spectral absorption in · most Cases outside the UV range, so that they are not suitably applicable for practical purposes.

It is also known that the aforementioned disadvantage can be avoided by using the organic photoconductive Body adds electron acceptor compounds, the 'tf acids or Lewis acids. For example, Japanese Patent Laid-Open No. 16578/1967 provides the suffix of less than 10 mol% of an electron acceptor to an organic photoconductive material has a particularly high photosensitivity for the UV range. U.S. Patent 3,484,237 a large amount of an electron accepting compound is added, i.e. 49 to 12 3 mol% of trinitrofluorenone are used as Electron acceptor the poly-9-vinylcarbazole of the organic photoconductive material added to provide high sensitivity for white light to reach.

However, since the electron acceptors used in these sensitization methods carry highly polar groups,

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they are generally insoluble or well crystalline in organic solvents. The disadvantage is that the species the solvents that can be used are limited and it is therefore difficult to prepare a photosensitive Layer arbitrarily select a suitable solvent for this. Furthermore, it is difficult to have a flat photosensitive Layer to form, since the electron acceptors crystallize extremely easily when their solvents evaporate during the coating process. Because the electron acceptor compounds are sparingly soluble, their amount that can be added is limited, which often has the consequence that in practical Applications the sensitizing effect of the electron acceptor cannot be fully achieved. There is also the compatibility of the electron acceptor with the organic photoconductive material is low, the acceptor compound crystallizes after a relatively short storage time on the surface of the photosensitive layer, so that it can be used is no longer given.

The invention is based on the object of new electron acceptor compounds to create that used as a sensitizer in conjunction with organic, photoconductive materials can be. Furthermore, the solubility of the electron acceptors in organic solvents should be improved so that the amount of the electron acceptor to be added

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and the choice of solvents that can be used can be increased. Finally, the compatibility of the electron acceptor should be in the photoconductive layer are increased, so that a long-term stabilization of the photosensitive Layer results.

According to the invention, this object is achieved by that electron acceptor compounds of the formula

COJi,

are used, in which R ₁ , R 2 and R _{3 are} nitro, cyano, halogen, trifluoromethyl, acyl, lower alkyl, lower alkoxy, aryl, araükyl 'or hydrogen; X is oxygen or the malononitrile group _{bound by double bonds and R 1} ^ is a substituted or unsubstituted alkyloxy, alkylamino, aralkyloxy, aralkylamino, aryloxy or arylamino group with 4 to C atoms and R .., R “and R_ can be the same or different and the number of carbon atoms in the lower alkyl or alkyloxy groups is preferably 1 to 6 for reasons of ease of manufacture.

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The additional advantage achieved by using the aforementioned compounds is that plasticizers, which are added in the preparation of the photosensitive layer and can reduce its sensitivity, their Amount can be reduced or omitted completely can. "

Exemplary compounds that can be used are given below.

(1) 7-Nitro-9-fluorenone-1-carboxylic acid butyl ester

(2) 4-Nitro-9-fluorenone-1-carboxylic acid octylamide

(3) 2,7-ninitro-9-fluorenone-1-carboxylic acid 3-methyl-U-isopropylphenyl ester

(4) S-nitro-B-bromo-S-fluorenone-1-carboxylic acid P-isopropylbenzyl ester

(5) 2-nitro-6,7-dichloro-9-fluorenone-1-carboxylic acid dihexylamide

(6) 2,7-dichloro-9-fluorenone-1-carboxylic acid benzylamide

(7) 2,6 ^ -tribromo-g-fluorenone-1-carboxylic acid laurylamide

(8) 7-cyano-9-fluorenone-1-carboxylic acid U-chlorobutyl ester

(9) 7-Ni "tro-9-fluorenone-2-carboxylic acid cetylamide

(10) 4,5 ^ -trinitro-g-fluorenone ^ -carboxylic acid octyl ester

(11) 2 ^ -Dichlor-g-fluorenone-S-carboxylic acid-P-anisidino

(12) 2-cyano-9-fluorenone-3-carboxylic acid P-aceto-phenyl ester

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(13) 2,7-Dinitro-9-fluorenone-4-carboxylic acid hexyl ester

(14) 2sSjT-Trinitro-g-fluorenone - ^ - carboxylic acid lauryl ester

(15) 2,7-dichloro-9-fluorenone-4-carboxylic acid 2-P-chlorophenoxyethyester

(16) 2, T-Dicyan-S-fluorenone-H-carboxylic acid-N-methyl-N-dodecylamide

(17) 2-Benzoyl-7-nitrile-9-fluorenone-4-carboxylic acid-2-ethpxylethylamide

(18) Cheryl 2T nitro-6-cyano-9-fluorenone-1-carboxylate

(19) 4,5-Dinitro-7-acetyl-9-fluorenone-2-carboxylic acid P-chlorobenzyl ester

(20) 4,5,7-trinitro-9-fluorenone-2-carboxylic acid decylamide

(21) 7-Chloro-8-methyl-9-fluorenone-2-carboxylic acid hexylamide

(22) 4,5-Dichloro-7-methoxy-9-fluorenone-2-carboxylic acid stearate

(23) 2-Benzyl-5, 7-dinitro-9-fluorenone-4-carbons-luretetradecylamide

(24) 8-Trifluoromethyl-9-fluorenone-2-carboxylic acid rotyl ester

(25) 2 ^ -Dinitro-g-Dicyanjnethylenfluoren-4-carb .hexylester

(26) 2-cyano-9-dicyanomethylene fluorene-3-carboxylic acid ethoxyethylene s ter

(27) 1, e-Dichloro-g-dicyanomethylene fluorene-4-carboxylic acid myristyl ester

(28) e ^ -Dibromo-g-dicyanomethylene fluorene-1-carboxylic acid -3, »- xyUdide

(29) 2,5,7-trinitro-9-dicyanomethylene fluorene-4-carboxylic acid stearylamide

(30) 4,5,7-trinitro-9-dicyanomethylene fluorene-2-carboxylic acid oleyl ester

The above compounds can generally be prepared from the corresponding 9-fluorenone carboxylic acids and 9-Fluorenone carboxylic acid esters or amides can be obtained by conventional methods of ester or amide preparation. 9-Dicyanmethylene fluorenone carboxylic acid esters and amides can can be prepared by adding the corresponding 9-fluorenone carboxylic acid with malononitrile (malononitrile) and then esterified or the amide is formed or by Reacts 9-fluorenonecarboxylic acid esters or amides with malononitrile.

Typical procedures for preparing the above compounds are given below.

Representation example 1;

2,7-Dinitro-9-fluorenone-4-carboxylic acid hexyl ester £ No. (13) of the above compounds]

3.11+ grams (0.01 moles) of 2,4-dinitro-9-fluorenone-4-carboxylic acid dissolved in 50 ml of hexyl alcohol by heating and, after adding 3 drops of sulfuric acid, kept at 150 ° C. for 4 hours.

After cooling, the precipitated yellow crystal became

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filtered off and the filtrate was distilled to dryness under reduced pressure. The residue was recrystallized from η-hexane with the above crystal, giving 2.86 g of the end product.
Elemental analysis:

calculated found 60.29% 60.40% 4.56% 4.51% 7.03% 6.98%

H
N

Representation example 2

2,7-Dinitro-9-dicyan-methylenfluorenone-4-carboxylic acid hexyl ester (25)

3.98 g (0.01 mol) of hexyl 2,7-initro-9-fluorenone-4-carboxylate were refluxed with heating in 200 ml of methanol and, after the addition of 1.98 g (0.03 mol) of malononitrile and refluxed 2 drops of piperidine for a further 20 hours. After the solvent had been distilled off, it was recrystallized from η-hexane, and 3.03 g of the end product were then obtained.
Elemental analysis:

calculated found

C 61.87% 61.52%

H 4.07% 3.99%

0 12.55% 12.48%

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Representation example 3

4,5,7-trinitro-9-fluorenone-2-carboxylic acid octyl ester (10)

3.59 g (0.01 mol) of 4,5,7-trinitro-9-fluorenone-2-carboxylic acid were refluxed in 30 ml of thionyl chloride for 5 hours and dried by distilling off excess thionyl chloride. The acid chloride obtained in this way was heated to 80 ° C. in 50 ml of octyl alcohol for 3 hours; then the octyl alcohol was distilled off under reduced pressure. The residue was recrystallized from hexane, 3.6 g of a pale yellow end product being obtained.
Elemental analysis:

calculated found

C 56.04% 56.17%

H . 4.50% 4.46%

0. 8.91%. 8.86%

Representation example 4

4,5,7-trinitro-9-fluorenone-2-carboxylic acid decylamide (20)

3.78 g (0.01 mol) of 4,5,7-trinitro-9-fluorenone-2-carboxylic acid chloride, which had been prepared as in Representation Example 3, were heated ^{to 80 ° C. with 50 ml of decylamine for 3 hours.} Then the decylamine was distilled off under vacuum. The residue was recrystallized from hexane. 4.06 g of a pale yellow end product were obtained.

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2Α0Π15

Elemental analysis:

calculated found

C 57.82% 57.71%

H 5.27% 5.32%

0 11.24% 11.20%

Representation example 5

1,6-dichloro-9-dicyan-methylenfluorenone-4-carboxylic acid myristyl ester (27)

2.93 g (0.01 mol) of I, B-dichloro-G-fluorenone-U-carboxylic acid was refluxed in 300 ml of methyl alcohol and after adding 2.0 g (0.03 mol) of malononitrile and two Keep drops of piperidine under reflux for a further 20 hours. After cooling, the deposited crystal was filtered off, and then 2.31 g of 1, G-dichloro-Q-dicyanomethylene fluorenone-4-carboxylic acid were obtained, which were refluxed in 30 ml of thionyl chloride for 5 hours to form the corresponding acid chloride.

After the excess thionyl chloride had been distilled off, the acid chloride was dissolved in 40 ml of myristyl alcohol at 80 ° C. for 3 hours boiled under reflux and then the myristyl alcohol is distilled off under vacuum. After recrystallization from n-hexane 3.18 g of end product were obtained.

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Elemental analysis

calculated found C. 69.26% 69.31% H . 6.39% 6.35% N 5.21%. 5.30% Cl 13.19% 13.12%

Organic photoconductive materials, as used in the present case, are preferably those which act as an electron donor, while the above compounds in combination with organic photoconductive materials can act as an electron acceptor. They therefore include low molecular weight organic photoconductive materials such as Amylhydrazone derivatives, oxadiazole derivatives, pyrazoline derivatives, imidazolone derivatives, imidazolinthione derivatives, benzimidazole derivatives, Benzoxazole derivatives and benzthiazole derivatives; also polymers with a heterocyclic ring, such as a carbazole ring, or polynuclear aromatic rings such as the naphthalene or anthracene ring. These connections are for example disclosed in Japanese Patent Laid-Open Nos. 10966/1959, 812/1961, 18674/1967, 25230/1967 and others.

Exemplary materials used as organic photoconductive substances in the present invention are the following:

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(A) polymers with a carbazole ring, such as poly-9-vinylcarbazole, 9-vinylcarbazole copolymer, 3-nitro-9-vinylcarbazole copolymer, S-methylamino-S-vinylcarbazole copolymer, nitrated poly-9-vinylcarbazole, 3,6-dibromo-9-vinylcarbazole copolymer, Poly-g-vinyl-S-aminocarbazole, chlorinated poly-9-vinylcarbazole, thiocyanated poly-9-vinylcarbazole, cyanated poly-9-vinylcarbazole, brominated poly-9-vinylcarbazole, 3-iodine-9-vinylcarbazole copolymer, Poly-SjB-dijod-g-vinylcarbazole, poly-3-benzylideneamino-9-vinylcarbazole, 3,6-dibromo-9-vinylcarbazole copolymer, otjW-di-parbazole alkane derivatives, vinylanthracene-9-vinylcarbazole copolymer, (2 or 3) vinyl-9-alkyl-carbazole polymer or • Copolymer (the alkyl group is among primary alkyl groups, such as Methyl, ethyl and propyl selected.)

(B) Aromatic amino derivatives such as amino-polyphenyl, (allylidene) azines, N, N-dialkyl-N, N'-dibenzylphenylenediamine, N, N, N ¹ , N'-tetrabenzylphenylenediamine, N, N'-diphenyl -p-phenylenediamine, N, N'-dinaphthyl-p-phenylenediamine, 4,4'-dimethylaminophendiphenone.

(C) Diphenylmethanes and triphenylmethanes such as diphenylmethane-leuco color base and triphenylmethane-leuco color base

(D) heterocyclic compounds such as oxadiazole, 5-aminothiazole, 4,1,2-triazole, imidazolone, oxazole, imidazole,

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Pyrazoline, imidazoline, polyphenylenethiazole, 1,6-methoxyphenezine, Pyrazolinopyrazoline derivatives and the like.

(E) compounds having a condensed ring such as benzothiazole, benzimidazole and benzoxazole, for example, 2- ⁽¹ t ^t -Diaminophenyl) -benzoxazole · and 2 - (4 ^f -Dimethylaminophenyl) -benzoxazole, amino acridine, quinoxaline, Diphenylenhydrazone, pyrrocoline derivatives ; 9,10-dihydroanthracene derivatives and the like.

(F) compounds with a double bond, such as

Acylhydrazone, ethylene derivatives, 1,1,6,6-tetraphenylhexatriene, and like-

(6) Condensation products such as condensation products of aldehydes and aromatic amines, reaction products of secondary aromatic amines and aromatic halides, Polypyromethane-imidopoly-p-phenylene-ljSji ^ oxadiazol- and the like.

(H) vinyl polymers (except polyvinyl carbazole), such as 00-alkylacrylic acid amide polymers, polyvinylacridine, poly-JjL, 5-diphenyl-3- (f-vinylphenyl) -2-pyrazolinT . Poly (1,5-diphenylpyrazoline), polyaceraphthylene, ring-substituted "polyacenaphylene, Polyvinyl anthracene, poly-2-vinyldibenzothiophene and the like.

Substances that give good results in the invention Sensitize these organic photoconductive materials

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supply are polymers with a carbazole ring and their derivatives, aromatic amino derivatives, öiphenylmethan- and Triphenylmethane derivatives.

To practice the invention, the organic photoconductive materials and the compounds of the invention are used dissolved in suitable solvents. The invention Compounds can be dissolved in numerous kinds of solvents, so that the most suitable solvent among a large Number depending on the organic photoconductive used Material can be selected. The amount of the compound of the present invention varies depending on its object. For example, when applied to a substrate such as paper, film and the like and as colorless or almost colorless transparent, photosensitive layer is used, the compound is in the proportion of 0.01 to 10 mol, preferably 0.1 to 5 moles per 100 moles of organic photoconductive material are added. (If the photoconductive material is a polymer the calculation becomes the molecular weight of the monomer unit of the polymer.) In this case a high light sensitivity for the UV range is achieved. Even if a high sensitivity for visible light is required is, this can be achieved by adding color sensitizers in such an amount that the photosensitive layer is not strongly colored.

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. 2A01115

When a high sensitivity to white light is required is, as with the main photosensitive plate, and if the coloration of the photosensitive plate is negligible a high ratio of 10 to 120 moles per 100 moles of organic photoconductive material can be used, to achieve the high sensitivity to visible light. The solution that the photoconductive material and the invention Contains compounds, if necessary, may contain binder resins and other additives with which a Substrate is coated or which are used in special cases in the form of an own substrate.

The following examples show embodiments of the invention without restricting its scope.

Verglexchsbexspxel I

The solutions obtained by dissolving 2.0 g of poly-9-vinylcarbazole in 30 ml of the following solvents, 10 mol% and 100 mol% were 2,4,7-trinitrofluorenone (TNF), based on poly-9-vinylcarbazole, added. The solubility the TNF in the solvents was measured and in the Table below, where the symbol 0 means that TNF is soluble and the symbol X means that TNF is insoluble.

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solvent

TNF

10 mol%

Chlorobenzene

Tetrahydrofuran

Cyclohexane

Pyridine

Dimethylformamide

(DMF)

Di ox on

1,2-dichloroethane f

Methylene chloride j
Chloroform I.

i
Toluene 'j

Benzene \

Carbon disulfide t

\
fabric f

0 0 0

0 0 0 0 X X X

100 mol%

X X X 0

0 X X X X X X mol% of the compounds as listed above

0 0 0 0

0 0 0 0 0 0 0

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Comparative example 2

Solutions, which had been prepared by dissolving 2 g of polyvinyl carbazole and 1.6 to 3 g of 2,4,7-trinitrofluorenone in 30 ml of dimethylformamide, were applied to an aluminum plate and heated for 10 minutes at 120 ° C. to form a 13 μm , thick ^ photosensitive layer dried. After the photosensitive layer was stored in a dark place for one week, it was observed that 2,4,7-trinitrofluorenone was crystallized and precipitated. In this example, when a photosensitive layer was formed using a solution containing 3.26 g of 2,4,7-trinitrofluorenone, it was also observed that 2,4,7-trinitrofluorenone precipitated and crystallized immediately after the phosphate-sensitive layer was formed. The precipitation as a result of crystallization was recognized by the opacity of the layer and the unevenness of its surface. When the above compounds (1) to (30) were used instead of 2,4,7-trinitrofluorenone in this comparative example, no precipitation due to crystallization was observed. In addition, pyridine was used in place of dimethylformamide with the same results.

Comparative example 3

Three photosensitive layers of polyvinyl carbazole, polyvinyl carbazole and 2,4,7 _T trinitrofluorenone or polyvinyl carbazole and 4,5,7-trinitrate-9-fluorenone-2-carboxylic acid octyl ester

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would u on a 75 thick polyester film coated whose surface was made hydrolphil. The thickness of the resulting photosensitive layer was adjusted to 4 It-. The cracking of the photosensitive layer was checked by winding the polyester film face-out around rollers having the following diameters. In the following table, symbol X means that cracks occurred in the photosensitive layer, and symbol 0 means that cracks did not occur.

diameter
(mm) Polyvinyl
carbazole PVK
(without addition) Trinitrofluorenone
TNF 100 mol% 4,5,7-trinitro-
9-fiu'orenone-2-
carboxylic acid octyl
ester 100 MoI 6th 0 10 mol% 0 10 mol% 0 5 0 0 • X 0 .0 X 0 X 0 0 3 X X X 0 0 X X

example 1

A solution of 2 g of 1,3,5-Trxphenylpyrazolxn, 2 g of polyvinylbutyral resin, 70, ¹ l mg of 7-cyano-9-fluorenoή-l-carboxylic acid-4-chlorobutylesterjyerbverbindungen (8) j and 50 ml of ethanol was on a

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Aluminum coated paper applied. After drying, about 6 u thick coating was obtained on a loan photoempfind paper. Then, the photosensitive paper thus formed was loaded in a dark environment and exposed through a positive microfilm master with a film enlarger equipped with a 500 W tungsten lamp. It was developed with a liquid developer to give an excellent positive image. The appropriate exposure amount was 600 lux. sec.

Example 2

A paper that had been treated with solvent to prevent penetration was treated with a solution of 2 g Ν, Ν, Ν ¹ , N'-tetrabenzyl-m-phenylenediamine, 2 g of polystyrene, ItM- mg 2.5.7- Trinitro-9-dicyanomethylene fluorenone-4-carboxylic acid stearylamide compound (29) | and 40 ml of toluene coated and dried to form a photosensitive paper. The thickness of the photosensitive layer was about 7 JX .

The photosensitive layer was loaded, exposed and developed as in Example 1. One received an excellent one Image. The appropriate exposure amount was 550 lux. sec.

Example 3

A solution made by dissolving 2 g of poly-3-methyl-9-vinylcarbazole and 38 mg of 2,7-dinitro-9-fluorenone-4-carboxylic acid

24Ü1115

hexyl ester compound (13) / prepared in 35 ml of chlorobenzene and a solution prepared by dissolving 11.6 mg of 9,9'-diethyl-3,3'-dicarbazolyl-phenylmethyl iodide (sensitized t dye) in 5 ml of methylene chloride were mixed to form a photosensitive solution. The photosensitive Solution was applied to a transparent polyester film on which aluminum was thinly deposited, and dried to a transparent photosensitive film having a 6 µm photosensitive layer. The photosensitive Layer was loaded, exposed and as in example

1 developed. An excellent copy of the image was obtained. The appropriate exposure amount was 150 lux. sec.

Example 4

An aluminum plate was covered with a solution

2 g of poly-9-vinylcarbazole, 4.9 g of 4,5,7-trinitro-9-fluorenone-2-carboxylic acid octyl ester "compound (10)" and 30 ml of chlorobenzene were coated so that a 10 JX thick, dry layer was formed . The photosensitive plate produced in this way was placed on a rotary electrometer and, after negative charging at -6 KV, exposed to a tungsten lamp (effective illuminance: 14.4 lux). The amount of exposure (half-value exposure) required to reduce the output potential from 9 50 V to half was 4.4 lux. sec.

When replacing the poly-9-vinylcarbazole with poly-3-chloro

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For 9-vinylcarbazole, the half-value exposure was 4.0 lux. sec and when using poly-3,6-chloro ~ 9-vinylcarbazole was the half-value exposure 3.6 lux s see.

Examples 5 to IQ

The following compounds were used to make photosensitive plates in place of 4,5,7-trinitro-9-fluorenone-2-carboxylic acid octyl ester of Example 4 used. The half-value exposure of the photosensitive plates was as measured in example 4 with the electrometer. The results are in the following. Given in the table.

In summary, the invention resides in a photosensitive Material for electrophotography, which acts as a sensitizer, compounds of the formula

contains, wherein R ₁ , R ₂ and R ₃ from the group consisting of nitro, cyano, halogen, trifluoromethyl, acyl, lower alkyl, lower alkoxy, aryl, aralkyl and hydrogen, X from oxygen and malononitrile and R ₁ ^ from the group are selected from a group consisting of substituted or unsubstituted alkyloxy, alkylamino, aralkyloxy, aralkylamino, aryloxy and arylamino and where R., R ₂ and R _{3 can be the} same or different.

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Example ; added

, Link

5 connection

6 connection 5

7 connection

8 connection

9 'connection connection

Amount (mol% based on poly-9-vinyl-carbazole)

At first-*
! potential

G (120 Mol%) 920V 4, 04 ε (100 Il \ 95OV 5.40 R. (80 ti \ 88OV 3.71 ς (50 Il) 900V 2.39 G (30 Il \ : 96OV 1.39 G (20 Il \ ; 960V 1.36

Half-value loan amount

5.2 lux. sec • 5.0 »"

6.0 »11.0" 18.5
24.0 "

Claims (3)

Claims lj Photosensitive material for the. Electrophotography, characterized in that it contains one or more organic photoconductive substances and one or more compounds of the formula COR, contains, wherein R ^, R ~ and R_ are identical or different and are nitro, cyano, halogen, trifluoromethyl, acyl, lower alkyl, lower alkoxy, aryl, aralkyl or hydrogen; X is oxygen or malononitrile and R ₁ ^ is substituted or unsubstituted alkyloxy, alkylamino, aralkyloxy, aralkylamino, aryloxy or aralamino with H to 30 carbon atoms. 2. Photosensitive material according to claim 1, characterized in that the compound represented by the formula is added in a proportion of 0.01 to 10 moles per 100 moles of the organic photoconductive material. 409829/10 oB 3. Photosensitive plate for electrophotography, characterized in that it is a layer of one or more organic, photoconductive substances and one or more compounds of the formula includes wherein R., R 'and R ₃ can be identical or different and are nitro, cyano, halogen, trifluoromethyl, acyl, lower alkyl, lower alkoxy, aryl, aralkyl or hydrogen, X is oxygen or} malononitrile and R ^ substituted or unsubstituted Alkyloxy, alkylamino, aralkyloxy, aralkylamino, aryloxy or arylamino with 4 to 30 carbon atoms mean, the ratio of this compound to the organic photoconductive material being 10 to 120 mol to 100 mol. 409829/1006