DE1904629A1 - Electrophotographic recording material - Google Patents

Description

EASTMAN KODAK COMPANY, Rochester, New York State, United States of America

Electrophotographic recording material

The invention relates to an electrophotographic recording material, consisting of a conductive substrate and at least one photoconductive layer applied to it Layer with an organic photoconductor and a cyanine dye which spectrally sensitizes the photoconductor.

It is known for dividing images on electrophotographic Ways to use electrophotographic recording materials made of an electrically conductive Layer support and a photoconductive insulating layer are made, their specific resistance in the dark is considerably larger than when exposed to actinic light. As part of electrophotographic processes These recording materials are usually initially kept in the dark in order to achieve the highest possible, uniformity Bring resistance in the photoconductive, insulating layer. Then the recording materials are im

19Q4629

The dark is electrostatically charged, negative or positive. The recording materials can then be exposed imagewise, the resistance being the photoconductive Layer is reduced imagewise according to the intensity of the irradiated amounts of light. In this way a latent, creates an electrostatic image. A visible image can then be generated from this electrostatic image by the latent image, for example by sputtering a finely powdered, meltable pigment, the particles of which carry an electrical charge that corresponds to the charge on the recording material opposite is being developed. The pigment particles can then be melted into the photoconductor layer or melted.

A wide variety of photoconductors have become known for the production of electrophotographic recording materials. Typical inorganic photoconductors are, for example, selenium and zinc oxide. Such inorganic photoconductors have the disadvantage that they are not suitable for the production of recording materials for reflex copier systems and that in their use in connection with transparent substrates do not allow images to be generated, unless by indirect means Measures.

When using organic photoconductors, these disadvantages can be avoided. The known organic photoconductors, however, again have the disadvantage that their sensitivity compared to visible radiation, "It is there" is relatively low became known / the spectral sensitivity of organic photoconductors through the addition of certain cyanine or lisröcysniü dyes, for example, by means of such dyes as listed in Table C below. However, it has been shown that the Verweftikiftg Dyes evoked a great deal of spectral sensitivity is low.

/ ~ z. B. from US patents 3,174,854 imu 3 041lös and British patent 964,873 ,,

The object of the invention was therefore to provide an electrophotographic recording material consisting of a conductive one Layer support and at least one photoconductor layer with an organic photoconductor and a photoconductor spectrally sensitizing dye to indicate which the Capable of effectively spectrally sensitizing photoconductors.

The invention was based on the knowledge that cyanine dyes of a first and a second 5- or 6-membered heterocyclic nitrogen-containing ring, the are linked to one another by a methine radical and whose first ring is a pyrazole ring with its 4-carbon atom is bonded to the methine radical, and the second ring of which consists of a ring typical of known cyanine dyes, preferably a so-called electron accepting ring, which is bonded to the methine residue with a carbon atom, is excellent effective, spectral sensitizing dyes for organic photoconductors are

The subject of the invention is thus an electrophotographic Recording material consisting of a conductive layer support and at least one photoconductive layer applied to it Layer with an organic photoconductor and a cyanine dye which spectrally sensitizes the photoconductor, thereby characterized in that it is a cyanine dye of the following structural formula as the spectral sensitizing dye contains:

R ₂

CNR ₄

(I) R ₁ -NC-CH-CH) -PC (-LsL) ^ _11n C

I ^X C «-

X I

R *

where mean:

8A97 1 233

L is an optionally substituted methine radical; R. an optionally substituted alkyl, Al

kenyl or aryl radical;

R ₂ and R _{3 are} hydrogen atoms, alkyl radicals or optionally substituted aryl radicals;

Typically an alkyl radical, an optionally substituted aryl radical or a radical of the formula

where mean: ρ β 1 or 2 and

Z ₁ the atoms required to complete a 5- or 6-membered heterocyclic ring customary for cyanine dyes;

M = 1 or 2;

η s 2 or 3;

X is an acid anion and Z the to complete one for cyanine color

substances usual S- or 6-membered heterocyclic ring required atoms

According to the invention for the production of electrophotographic Cyanine dyes used for recording materials have the property that if they have a negative gelatin

9/1233

Silver bromoiodide emulsion with 99.35 mole percent bromide and 0.65 mole percent iodide are incorporated in a concentration of 0.2 millimoles of dye per mole of silver halide, desensitize this emulsion by more than 0.4 log Ε units if the test emulsion is applied to a conventional Layer support exposed through a step wedge, in a sensitometer (to achieve D _ma ") with light from a wave length of 365 nanometers and exposed for 3 minutes at 20 ° C in a developer A of the following composition:

N-methyl-p-aminophenol sulfate 2.0 g Sodium sulfite, dehydrated 90.0 g Hydroquinone 8.0 g Sodium carbonate, monohydrate 52.5 g

Potassium bromide 5.0 g made up to 1.0 liter with water

developed and finally fixed in the usual way, washed and is dried.

The one used for the test! negative silver bromoiodide emulsion can be produced as follows:

A solution is placed in a temperature-controlled container CA) filled with the following components:

Potassium bromide 165 g Potassium iodide 5 g

Gelatin 65 g

Water 1700 ml.

A filtered solution (B) of the following composition is placed in another container:

905049t / 1233

Silver nitrate 200 g

Water 2000 ml.

The solution (A) is brought to a temperature of 54 ⁰ C. The solution (B) is transferred to a separating funnel and likewise heated ^{to 54 ° C.} The silver nitrate solution is then run from the separating funnel through a calibrated nozzle into the container containing the solution (A), the contents of the container being constantly agitated during the precipitation of the S over halide and the ripening. The movement is also continued later when the emulsion is finally prepared by means of a mechanical stirrer. The silver halide is precipitated over a period of 10 minutes.

The dyes used according to the invention are desensibly glazed thus common negative silver halide emulsions. Such emulsions have their own sensitivity to them blue radiation. The dyes used according to the invention reduce this sensitivity · In addition, the dyes used according to the invention have practically no spectral effects Sensitization of such emulsions. With regard to then it was extraordinarily surprising to find that the same dyes to spectrally sen organic photoconductors raise awareness.

Another feature of the cyanine dyes used according to the invention is that they are practically non-photoconductive are. With "practically not Phetoleitfföig" is meant, that no image is produced when using them if a solution of 0.002 g of the dye and 0.5 g of a foliar binder (the same as in Examples 1 to 6 below specified composition) dissolved in 5.0 ml of methylene chloride and when the solution is applied to a substrate in the absence of a photoconductor and when that; Recording material is tested in the way it is, w-is "" - it. eat the later following Examples T to 6 described

It has been shown that the inventively used Cyanine dyes are able to increase the sensitivity of organic photoconductors extremely favorably, namely by Expansion or increase in the responsiveness of the photoconductors to visible radiation, i.e. radiation of the area from about 400 to 700 nanometers. The dyes used according to the invention obviously act as spectral sensitizers when they are more common for sensitization effective organic photoconductors can be used. If they are used together with organic photoconductors whose effectiveness is low or insufficient, the dyes used according to the invention act as compounds which increase sensitivity and also as spectral sensitizers.

In the structural formula I given, the methine radical represented by L can, for example, be replaced by an alkyl or Aryl radical, i.e. L can be, for example, a methine radical of the following formulas:

-QI =, -C (CH ₃ ) * or -C (CjS,.) ".

If Rj has the meaning of an optionally substituted alkyl radical Sj, this preferably has 1 to 12, in particular 1 to 4, carbon atoms. If R «represents an unsubstituted alkyl radical, this can be an aliphatic or a cycloaliphatic alkyl radical. In detail, R _{1 can} thus be, for example, a methyl, ethyl, propyl, isopropyl, butyl, hexyl, cyclohexyl, decyl or dodecyl radical.

If Rj has the meaning of a substituted alkyl radical, then this can for example consist of a hydroxyalkyl radical, e.g. an i-hydroxyethyl or -hydroxybutyl radical or an alkoxyalkyl radical, e.g. a 0-methoxyethyl or «-

909849/1233

Butoxybutyl radical or a carboxyalkyl radical, for example a β-carboxyethyl or -carboxybutyl radical or a sulfoalkyl radical, for example a β-sulfoethyl or α-sulfobutyl radical or a sulfatoalkyl radical, for example a β-sulfatoethyl or -sulfatobutyl radical, for example an acyloxyalkyl radical -Acetoxyäthyl-, γ-Acetoxypropyl- or ω-Butyryloxybutylrest or an alkoxycarbonylalkylrest, for example a ß-Methoxycarbonyläthyl- or ß-Äthoxycarbonylbutylrest. Furthermore, R ₁ can be, for example, a benzyl or phenethyl radical.

If R. has the meaning of an alkenyl radical, this preferably has 3 to 4 carbon atoms and consists, for example, of an allyl, 1-propenyl or 2-butenyl radical.

If Rj has the meaning of an aryl radical, this exists preferably from an aryl radical of the phenyl or naphthyl series, i.e. R. can be, for example, a phenyl, tolyl, XyIyI, methoxyphenyl, chlorophenyl or naphthyl radical.

If R ₂ and R ₃ are alkyl radicals, these likewise preferably have 1 to 12 and in particular 1 to 1 carbon atoms. For example, R ₂ and R- can consist of methyl, ethyl, propyl, isopropyl, butyl, hexyl, decyl or dodecyl radicals. If R ₂ and R- are optionally substituted aryl radicals, these preferably consist of optionally substituted aryl radicals of the phenyl or naphthyl series. In this case, R ₂ and R _{3 can be,} for example, phenyl, tolyl, XyIyI, methoxyphenyl, chlorophenyl or naphthyl radicals.

X can be one of the anions present in commonly known cyanine dyes, i.e. for example a chloride, Bromide, iodide, thiocyanate, sulfamate, perchlorate, p-toluenesulfonate, methyl sulfate or ethyl sulfate anion.

/ "Aralkyl radical, e.g.

909849/1233

If R. has the meaning of an alkyl radical, this likewise preferably has 1 to 12, in particular 1 to 4, carbon atoms. For example, R ₄ can consist of a methyl, ethyl, propyl, isopropyl, butyl, hexyl, cyclohexyl, decyl or dodecyl radical.

If R _{4 has} the meaning of an aryl radical, this preferably consists of an optionally substituted aryl radical of the phenyl or naphthyl series. In this case, R. consists, for example, of a phenyl, tolyl, XyIyI, methoxyphenyl, butoxyphenyl, chlorophenyl or fluorophenyl radical »

For example, Z. may represent the atoms necessary to complete a thiazole; 4-i-methylthiazole-; 4-phenylthiazole-; 5-methylthiazole-; 5-phenylthiazole-; 4,5-dimethylthiazole-; 4,5-diphenylthiazole-; 4- (2-thienyl) thiazole-; Benzothiazoles 4-chlorobenzothiazole-; 4-chloro-S-nitrobenzothiazole-; 5-chlorobenzothiazole-; 6-chlorobenzothiazole-; 7-chlorobenzothiazole-; 4-methylbenzothiazole-; 5-methylbenzothia-ZOI-; 6-i>methylbenzothiazole-; 4- or 5-nitrobenzothiazole-; 6-nitrobenzothiazole-; 5-bromobenzothiazole-; 6-bromobenzothiazole-; S-chloro-o-nitrobenzothiazole-; 4-phenylbenzothiazole-; 4-methoxyb benzothiazole-; 5-methoxybenzothiazole-; 6-methoxybenzothiazole-; 5-iodobenzothiazole; 6-iodobenzothiazole-; 4-ethoxybenzothiazole; 5-ethoxybenzothiazole-; Tetrahydrobenzothiazole-; 5,6-dimethoxybenzothiazole-; 5,6-Dioxymethylenbenzothiazol- ι E-Hydroxybenzothiazol-; 6-hydroxybenzothiazole-; Naphtho ^ "2, id ^ thiazol-; Naphthol" 1,2-d _- 7thiaiol-; N * phtho ^ "2,3-d _- 7thiazole-; 5-methoxynaphtho /"2,3-d_7thiazole-; 5-Xthoxynaphtho ^ "i, 2-d _- 7thiazole-; 8-IIethoxynaphtho ^" 2,1 -d ^ thiazole-; 7-methoxynaphtho ^ "2,1 -d_7-thiazol-; 5-methoxythianaphthen- ^ '* 7 _i 6-d _< _7thiazole or a naphthothiazole ring substituted by a nitro radical;

an oxazole; 4-methyloxazole-; 4-nitrooxazole-; 5-methyloxa-20I-J 4-phenyloxazole-; 4,5-diphenyloxazole-j 4-xthyloxazole-;

909849/1233

4,5-dimethyloxazole-i 5-phenyloxazole-; Benzoxazole-; 5-methylbenzoxazole-; 5-phenylbenzoxazole-; 5- or 6-nitrobenzoxazole-; S-chloro-o-nitrobenzoxazole-; 6-methylbenzoxazole-; 5,6-dimethylbenzoxazole-; 4,6-diraethylbenzoxazole-; 5-methoxybenzoxazole-; 5-ethoxybenzoxazole-; 5-chlorobenzoxazole-; 6-methoxybenzoxazole-; 5-hydroxybenzoxazole-; 6-hydroxybenzoxazole-; Naphtho ^ "2,1-d_7oxazol"; Naphtho ^ ~ 1,2-d _ep 7oxazole or a naphthoxazole ring substituted by a nitro radical;

of a selenazole-j 4-methylselenytazole-; 4-nitroselenazole-; 4-phenylselenazole-; Benzoselenazole-; 5-chlorobenzoselenazole-; 5-methoxybenzoselenazole-; 5-hydroxybenzoselenazole-; 5- or 6-nitrobenzoselenazole-; S-cliloro-ö-nitrobenzoselenazole-; Tetrahydrobenzoselenazole »; Naphtho ^ ~ 2,1-d _- 7selenazole-; Naphtho / "1,2-d_7selenazol- or a naphthoselenazole ring substituted by a nitro radical;

a thiazoline; 4-methylthiazoline or 4-nitrothiazoline ring;

a pyridine ring, e.g., a 2-pyridine; 5-methyl-2-pyridine-; 4-pyridine-; 3-methyl-4-pyridine or one by one Nitro radical substituted pyridine ring;

a quinoline ring, e.g., a 2-quinoline; 3-methyl-2-quinoline-; 5-ethyl-2-quinoline-; ö-chloro-Z-quinoline-; 6-nitro-2-quinoline-; 8-chloro-2-quinoline-; δ-methoxy-Z-quinoline-; 8-ethoxy-2-quinoline-; e-hydroxy-1-quinoline-j 4-quinoline-; 6-methoxy-4-quinoline-; 6-nitro-4-quinoline- | 7-methyl-4-quinoline-; 8-chloro-4-quinoline-; 1-isoquinoline-; 6-nitro-i-isoquinoline-; 3,4-dihydro-i-isoquinoline or 3-isoquinoline ring;

a 3,3-dialkylindolenine ring, which is preferably substituted by a ma nitro or cyano radical, for example a 3,3-dimethyl-S or 6-nitroindolenine or 3,3-dimethyl-S or 6-cyanoindolenine radical or

909849/1233

of an imidazo1-; 1-alkylimidazole-; i-alkyl-4-phenylimida-20I-; i-alkyl- ^ S-dimethylimidazole-; Benzimidazole-; 1-alkylbenziraidazole-; i-aryl-S ^ ö-dichlorobenzimidazole-; 1-alkyl-1H-naph ^ "i, 2-d_7imidazole-; 1-aryl-3H-naphthol , 2-dJ- imidazole- or 1-alkyl-5-methoxy-1H-naphth ^ ~ 2,1-d_7iniidazolringes ·

For example, Z can represent the atoms required to complete one of the rings specified for Z-. Further, Z may for example represent the non-metallic atoms necessary to complete an imidazo ^ "4,5-b _(IP 7chinoxalinringes _l, for example, a 1,3-Dialkylimidazo ^ ~ 4,5-b_7chinoxalinringes, for example a 1,3-Diäthylimidazo - / "4,5-b_7quinoxalin- or 6-chloro-1,3-diethylimidazo- ^ ~ 4,5-b_7quinoxalinringes, a 1,3-dialkenylimidazo- ^ ~ 4,5-b_7quinoxalinringes _t for example a 1,3-diallylimidazo - ^ "4,5-b_7quinoxaline or 6-chloro-1,3-diallylimidazo ^" 4,5-b_7quinoxaline ring or a 1,3-diarylimidazo ^ "4,5-b_7quinoxaline ring, for example a 1,3-diphenylimidazo - ^ "4,5-b_7quinoxaline ring or a 6-chloro-1,3-diphenylimidazo / ~ 4 _f 5-b_7quinoxaline ring;

of a 3,3-dialkyl-3H-pyrrolo ^ "2,3-b_7pyridinringes, e.g. a 3,3-dimethyl-3H-pyrrolo ^" 2,3-b _- 7pyridin- or 3,3-diethyl-3H-pyrrolo / ~ 2,3-b _{<> i} 7pyridine ring or

of a thia2olo ^ "4,5-b _- 7-quinoline ring.

Particularly advantageous cyanine dyes have proven to be those of the formula I given in which Z represents the atoms required to complete an electron-accepting ring, ie, for example, a thiazole, oxazole, selenazole, thiazoline, pyridine, quinoline substituted by a nitro radical -, 3,3-dialkylindolenine or imidazole ring or a Imidtzo ^ "* 4,5-b _ii> 7chinoxalin j-3,3-dialkyl-3H-pyrrolo ^" ^ 2,3 7PXrIdIn- or a thiazolo l ~ 4 , 5-b _- 7quinoline ring

9 ^ 09849/1233

An electron accepting or electron accepting ring is to be understood here as a ring which, after converting it into a symmetrical carbocyanine dye and adding it to a gelatin-silver chlorobromide emulsion with 40 mol percent chloride and 60 mol percent bromide in a concentration of 0.01 to 0.2 g of dye per mole of silver by electron trapping leads to an at least 80-time loss of the blue sensitivity of the emulsion when it is sensitometrically exposed and 3 minutes long developed in a developer having the composition already indicated at 20 ⁰ C. Particularly advantageous electron-accepting rings are those which, after conversion into a symmetrical carbocyanine dye and testing in the manner described, lead to a practically complete desensitization of the test emulsion to blue radiation. Practically complete desensitization means that the emulsion loses at least 90 tons, preferably 95%, of its sensitivity to blue radiation.

The cyanine dyes which can be used according to the invention for the production of an electrophotographic recording material from given formula I can easily be prepared by conventional methods by heating a mixture of a heterocyclic, quaternary salt of the following formula II:

CU) R ₁ -N

wherein m, R ₁ , X and Z have the meanings already given, and a pyraz oil compound of the following formula III:

^R 2 (III) R ₄ -NC

N * C
I.

^R 3
909849/1233

in which η, L, R ₂ , R- and R _{4 have} the meanings already given. The two compounds are preferably mixed with one another in practically equimolar proportions, expediently in the presence of a condensing agent such as anhydrous sodium acetate, a trialkylamine, for example triethylamine, etc., piperidine, an N-alkylpiperidine and the like in a medium such as ethanol, acetic anhydride and Like. Implemented. The crude dyes can then be separated from the reaction mixture and purified by single or multiple urocrystallization from suitable solvents, for example ethanol. Further details of the preparation of the dyes are described in Belgian patent 693,356.

Cyanine dyes suitable for the production of the electrophotographic recording material according to the invention are For example, the dyes I to XXX listed in Table A below:

- 14 -

Ö09S49 / 1233

Table A.

Dye No Compound

I. 3-Ethy1-2 - ^ "(1-pheny1-4-pyrazoIyI) vinyl_7-

benzothiazolium p-toluenesulfonate

^C 6 ^H 5

^C 2 ^H 5

II, 2 - / "(3,5-dimethyl-t-phenyl-4-pyrazolyl) vinyl_7 ·

3-ethylbenzothiazolium iodide

CH

C-CH = CH-C ^ J

CsasN

CH

III, 3-Ethyl-2 - ^ "(1,3,5-trimethyl-4-pyra2olyl) vinyl _- 7 ·

benzothiazolium iodide

C-CH = CH-C

C N-CH,

9 0 9 8 A 9/1 2 3 3

² "fi" ¹ "(2-benzothiazolyl) -3,5-dimethyl-4-pyrazolyl_7vinyl} -3-ethylbenzothiazolium iodide

3.

C-CH = CH-C

-N-C

^C 2 ^H 5

Cs

CH.

1,3,3-trimethyl-2- ^ ~ (1-phenyl-4-pyrazolyl) vinyl _- 7-3H-indolium iodide

CH

αϊ,

C-CH = CH-C

CH,

C-

-NC ₆ H ₅

2- [Cl- (Z-Benzothiazolyl) -3,5-dimethyl-4-pyrazolyl_7vinylj -1,3,3-trimethyl-3H-indolium iodide

CH

9098A9 / 1233

5,6-dichloro- 2-f (3,5-dimethyl-1-pheny 1-4-pyrazolyljvinyl-1, 3-diethylbenzimidazolium iodide

( CH ₇
I ³ C-CH = CH-C > v I Cl - ^: 2 ^H 5 C NC ₆ H ₅ Ι ^θ CaerN I. egg - « CH ₃ ( * ^^ i ^ ^: 2 ^H 5

6-Dimethylanano-2 - / "(3 _t 5-dimethyl-1-phenyl-4. Pyrazolyl) vinyl_7-1-methylquinolinium iodide

CH

6-Dimethylamino-1 -methyl-1- £ (1-pheny 1-4-pyrazolyl) yinyl-7-quinolinium iodide

H I

.NC ₂ H ₅

CH »CH-C

τθ

CH,

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2- {£ ~ 1 - (2-Benzothiazolyl) -3,5-dimethyl-4-pyrazolyl _- 7vinyl} -1-ethylquinolinium iodide

^ CH = CH-C

^C 2 ^H 5 CH,

CH-

N-L

-Z - / "(3,5-diraethyl-1-phenyl-4-pyrazolyl) vinyl_7imidazo /" 4,5-b _- 7quinoxaliniuraiodid

CH ₂ = CHCH ₂

CH.

NC ₆ H ₅

N ^ N

CH ₂ = CHCH ₂

CH

2 - / "(3,5-Dimethyl-1-phenyl-4-pyrazolyl) vinyl_7 · 1,3-diethylimidazo / "4,5-b-7quinoxalinium iodide

^C 2 ^H 5

y:

C-CHsCH-C

τθ

^C 2 ^H 5

CH ₃ C- N-

C-N

CH,

90984 9/1233

6 ~ chloro-2- / ~ (3,5-dimethyl-1-phenyl-4-pyrazolyl) vinyl_7-1,3-diphenylimidazo / ~ 4,5-b_7quinoxalinium- £ -toluenesulfonate

CH.

C-CH = CH-C

CH,

^C 6 ^H 5

2 "C (3,5-dimethy1-1-phenyl-4-pyrazolyl) vinyl_7-1» 3-diphenylimidazo / "4,5-b_7quinoxalinium iodide

^C 6 ^H 5

C-CH = CH-C

^C 6 ^H 5

CH,

C =

CH,

NC _n H ₁ .

D 5

-Z- / "i- (2-benzothiazolyl) -3,5-dimethyl.4-pyrazolyl_7vinyl imidazo /" 4 _# 5-0 ^ -7quinoxaline- £ -toluenesulfonate

CH ₂ = CH-CH ₂

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1, S-Diallyl-ö-chloro-Z - ^ "(3,5-dimethyl-1-phenyl-4-pyrazolyl) vinyl_7iinidazo ^" 4,5-b_7quinoxalinium-

£ -toluene sulfate

CH ₂ = CH-CH ₂

CH ₂ = CH-CH ₂

CH.

C = I

CH.

= N

Z - ^ 'O, 3,5-trimethyl-4 pyrazolyl) vinyl _ 7 imidazo ^ "4,5 ^ ,, £ -toluenesulfonate

CH ₂ = CH-CH ₂

N-CH,

CH ₂ = CH-CH ₂

OSO ₂ C ₇ H ₇

XVIII. 2 - ^ "(3,5-dimethyl-1-phenyl-4-pyrazolyl) vinyl_7-3-ethyl-6-nitrobenzothiazolium] 3-toluenesulfonate

C-CH = Ql-C

CH ₃

.C NC ₆ H ₅

C »

CH,

-N

OSO-C ₇ H ₇

4 »I /

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2- ^ ~ (3,5-Dimethyl-1-phenyl-4-pyrazolyl) vinyl_7-1,3,3-trimethyl-3H-pyrrolo ^ ~ 2,3-b_7pyridinium iodide

CH.

CH,

C-CH = CH-C.

τθ

CH

CH.

CH.

2-1 " (3,5-dimethyl-1-phenyl-4-pyrazolyl) vinyl_7-1, SjS-trimethyl-S-nitro-SH-indolium-p-toluenesulfonate

C-CH = CH-C

CH.

C = I

CH,

.NC ₆ H ₅

: N

OSO ₂ C ₇ H ₇

5-chloro-2- ^ ~ (3,5-dimethyl-1-phenyl-4-pyrazolyl) ■ vinyl_7-3-ethyl-6-nitrobenzothiazolium iodide

CH

Cl

.C-CH = CH-C

CH,

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2 - / "(3,5-Dimethyl-1-phenyl-4-pyrazolyl) vinyl _> _7 · 3-ethylthiazolo ^ ~ 4,5-b_7-quinolinium chloride

NC ₆ H ₅

XXIII.

2 - ^ "(3,5-Dinethyl-1-phenyl-4-pyrazolyl) vinyl _{ii (} 7-1-ethyl-6-nitroquinolinium iodide

1,3-Diallyl-2 - ^ "(1-phenyl-4-pyrazolyl) vinyl_7-imidazo £" 4,5-b_7-quinoxalinium-p-toluenesulfonate

H, CNC ₆ H ₅

-CH ^ CH-C

CH ₂ = CH-CH ₂

C =

O ₃ SC ₇ H ₇

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6-chloro-1,3-diphenyl-2- £ "" (1-phenyl-4-pyrazolyl) -vinyl_7-imidazo / "4,5-b_7-quinoxalinium-p-toluene-

sulfonate

-CH = CH-C

6 5

Θ,

O ₃ SC ₇ H ₇

XXVI. 3-ethyl-6-nitro-2- ^ ~ (1-phenyl-4-pyrazolyl) vinyl_7-

benzothiazolium p-toluenesulfonate

O ₃ SC ₇ H ₇

XXVII. 3-ethyl-6-nitrol-2 - ^ "(1 _t 3,5-triiaethyl-4-pyrazolyl)

vinyl_7benzothiazolium-p-toluenesulfonate

CH,

i-GL

C-CH = CH-C

-N

I CH,

'O ₃ SC ₇ H ₇

9098497T233

XXVIII. 1,3-Diallyl-2- {£ ~ 1- (2-benzothiazolyl) -3,5-dimethy1-4-PyTaZoIyI _- ZViHyI} -6-chloroimidazo ^ ~ 4, S-bJ? · Quinoxalinium-£ -toluenesulfonate

CH ₂ = CH-CH ₂

C-CH = CII-C

CIi.

γ N-C

C *

CIL

O ₃ SC ₇ H ₇

XXIX. 2 - {^ ~ 1- (2-Benzothiazolyl) -3,5-dimethyl-4-pyrazolyl_7 ·

vinyl} -3-ethyl-6-nitrobenzothiazolium- £ -toluenesulfonate

O ₂ N

-CH = CH-C

C ^ N-

CH

O ₃ SC ₇ H ₇

2- / ~ (3,5-Dimethyl-1-phenyl-4-pyrazolyl) vinyl _- 7 · 3-methylthiazolinium iodide

2
2

> CH = CH-C

CH ₃ + * ? " ^C 6 ^H 5

CH,

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Other beneficial dyes for making the electrophoto graphic recording material of the invention are for example:

4- ^ ~ (3,5-Dimethyl-1-phenyl-4-pyrazolyl) butadienyl_7-3-ethyl »· 6-nitrobenzoselenazolium £ -toluenesulfonate;

1,3-diallyl-2 - {^ "i- (2-benzoxazolyl) -3,5-dimethyl-4-pyrazolyl_7-viny1} imidazo /" 4,5-b _- 7chinoxaliniumiodid;

2 - {^ ~ 1- (2-Benzoselenazolyl) -3,5-dibutyl-4-pyrazolyl_7vinyl} -3-ethylbenzothiazolium iodide;

2 - {^ "3, S-diethyl-1- (2-quinolyl) -4-pyrazolyl, 7vinyl} -1-ethylquinolinium iodide;

2 - {{3,5-Dimethyl-1- ^ "2- (3,3-dimethyl-3H-indolyl) _e 7-4-pyrazolyl} -vinylJ-S-ethylbenzoxazolium-jj-toluenesulfonate;

2 - {{1- £ ~ 2- (1-ethylbenzimidazolyl) _7-3,5-dimethyl-4-pyrazolyl} vinyl} -3-ethylbenzoselenazolium methanesulfonate;

2 - {^ ~ 3,5-dimethyl-1- (2-thiazolyl) -4-pyrazolyl_7vinyl} -3-methylthiazolium iodide;

2 - {^ "3,5-dimethyl-1- (2-pyridyl) -4-pyrazolyl _e 7vinyl} -1-ethylpyridinium iodide;

2 - {^ "i- (2-Benzothiazolyl) -3,5-dimethyl-4-pyrazolyl_7vinyl} -3-alkyl (methyl, ethyl, propyl, isopropyl, butyl, etc.) - benzothiazolium salts (e.g. the chlorides, perchlorates and £ - Toluenesulfonates) and the corresponding benzoxazolium and benzoselenazolium salts;

2 - ^ "(3,5-Dimethyl-1-phenyl-4-pyrazolyl) vinyl_7-3-ethyl-6-nitrobenzoxazolium salts (e.g. the chlorides, perchlorates and £ -Toluenesulfonate);

2 - ^ "3,5-diraethyl-1-phenyl-4-pyrazolyl) vinyl _-i 7-3-ethyl-6-nitrobenzoselenazolium salts (e.g. the chlorides, perchlorates and ^ -toluene sulfonates) and the like.

909849/1233

For the preparation of an electrophotographic recording material according to the invention, a dye or can several of the dyes which can be used according to the invention are used will. All of the dyes described are excellent spectral sensitizing dyes for organic photoconductors. The electrophotographic recording material of the invention may be one or more the usual known organic photoconductors included. These include the so-called monomers, as well as the so-called polymeric organic photoconductors. The dyes described are of particular importance for increasing the sensitivity organic photoconductors which are practically insensitive or which have only a low sensitivity, i.e. a Sensitivity of less than 25, generally less than 10, when following the example described in Examples 1 to 1 below 6 are tested for their sensitivity to radiation from 400 to 700 nanometers.

Particularly advantageous organic photoconductors have proven to be those which have become known as organic photoconductors of the amine type. A common feature of such photoconductors is that they contain at least one amino group.

Photoconductors suitable for producing an electrophotographic recording material according to the invention are therefore, for example, arylamines, for example (1) diarylamines, for example diphenylamine, dinaphthylamine, N, N ^f -diphenylbesizidine, N-phenyl-1-naphthylamine; N-phenyl-2-naphthylamine; N, N ^? -Diphenyl-pphenylenediaminej 2-carboxy-5-chloro-4 ^l -methoxydiphenylamine; p-anilinophenol; N, N ¹ -di-2-naphthyl-p-phenylenediamine; 4,4'-benzylidene-bis (N, N-diethyl-m-> toluidine) _ft the amines known from US Pat. No. 3,240,597 and (2) triarylamines, such as (a) non-polymeric triarylamines, for example triphenylamine; Ν, Ν, ίΡ, Ν ¹ -Tetr & phenyl-m-phenylenediamine | 4-acetyl triphenylamine: 4-hexanoyl- ¹ enylamine; 4-lauroyl triphenyl ain; 4-hexyliriphenyl * »in;

909848/1233

4-dodecyl triphenylamine; 4,4'-bis (diphenylamino) benzyl; 4,4 · - bis (diphenylamine) benzophenone and the like and (b) polymeric triarylamines, for example poly ^ ^- N, 4 "- (N, Ν ·, N'-triphenylbenzidine) _7; polyadipyltriphenylamine; polysebacyltriphenylamine; polydecamethylene triphenylamine; polydecamethylene triphenylamine; -N- (4-vinylphenyl) diphenylamine; poly-N- (vinylphenyj) -o, a'-dinaphthylamine and the like.

Further advantageous photoconductors that can be used to manufacture the Electrophotographic recording material according to the invention are suitable, for example, in the US patent 3,265,496. Such photoconductors include those of the following structural formula:

Herein mean:

A is a mononuclear or polynuclear, divalent, aromatic, either condensed or linear radical, e.g. Phenylene, naphthylene, diphenylene or binaphthylene radical, or a substituted, divalent aromatic radical of this Type in which the substituent (s) can consist of acyl radicals having 1 to about 6 carbon atoms, e.g. acetyl, propionyl or butyryl radicals, or alkyl radicals having 1 to about 6 Carbon atoms, e.g. methyl, ethyl, propyl or butyl radicals, or alkoxy radicals with 1 to about 6 carbon atoms, e.g. methoxy, ethoxy, propoxy or pentoxy radicals, or nitro radicals;

90984 9/123

A ^{1 is} a mononuclear or polynuclear, monovalent, aromatic, either condensed or linear radical, for example a phenyl, naphthyl or biphenyl radical, or a substituted monovalent, aromatic radical of this type, the substituent or substituents of which can consist, for example, of acyl radicals with 1 to 6 Carbon atoms, e.g. acetyl, propionyl or butyryl radicals, or alkyl radicals with 1 to 6 carbon atoms, e.g. methyl, ethyl, propyl or butyl radicals, or alkoxy radicals with 1 to 6 carbon atoms, e.g. methoxy, propoxy or pentoxy radicals, or nitro radicals ;

Q is a hydrogen atom, a halogen atom or an aromatic amino radical, for example of the formula A ¹ NH-, in which A ^{1 has} the meaning already given;

b is a number from 1 to 12 and

G is a hydrogen atom, a mononuclear or polynuclear, aromatic, either condensed or linear radical, e.g. a phenyl, naphthyl or biphenyl radical, or a substituted aromatic radical, the substituent or substituents of which can consist, for example, of an alkyl, alkoxy, Acyl or a nitro radical or a poly (4'-vinylphenyl) radical attached to the nitrogen atom through a carbon atom of the Phenyl radical is bound.

For the production of the electrophotographic recording material according to the invention, nitrogen-containing, heterocyclic compounds are also suitable, for example compounds such as 1,3,5-triphenyl-2-pyrazoline and 2,3,4,5-tetraphenylpyrrole.

Photoconductors have proven to be particularly advantageous for the production of the recording material according to the invention, which consist of polyarylalkanes. Such photoconductors are for example described in US Pat. No. 3,274,000,

909849/1233

French Patent 1,383,461 and Belgian Patent 696 114.

Such photoconductors include diaryl and leuco bases Triarylmethane dye salts, 1,1,1-triarylalkanes, in which the alkane radical has at least 2 carbon atoms, and Tetraarylmethanes, of these compounds at least one aryl radical which is bonded to the alkane radical or to the methane residue, is substituted by an amino residue. The two last The named classes of photoconductors do not consist of leuco bases

Particularly advantageous for the production of the electrophotographic Polyarylalkane photoconductors suitable for recording material according to the invention can be represented by the following structural formula:

R "

Rt J R "t

R ""

Herein mean:

R ", R" ¹ and R ¹¹¹¹ aryl radicals and

R * is a hydrogen atom, an alkyl radical or an aryl radical, with the ^{proviso that at least one of the radicals R ", R 1} " and R ¹¹ "has an amino substituent.

The aryl radicals bonded to the central carbon atom preferably consist of phenyl radicals, although advantageous photoconductors are also present when the aryl radicals consist of naphthyl radicals. The aryl radicals can optionally be substituted, for example by alkyl and alkoxy radicals with

909849/1233

preferably 1 to 8 carbon atoms, hydroxy radicals or halogen atoms, these substituents in the o-, m- or p-position. Photoconductors with o-substituted phenyl radicals have proven particularly advantageous.

The aryl radicals can optionally also be linked to one another or be cyclized, in which case they can form a fluorene radical, for example. The amino substituent lets through reflect the following structural formula:

-I

wherein each substituent R _{5 can} consist of an alkyl radical with preferably 1 to 8 carbon atoms, a hydrogen atom, an aryl radical, preferably of the phenyl or naphthyl series, or where both substituents R ₅ together can represent the atoms required to form a heterocyclic amino radical with preferably 5 to 6 atoms are required in the ring. Such rings can be, for example, morpholino, pyridyl or pyrryl rings. At least one of the radicals R ", R" ¹ or R ¹¹ "preferably consists of a p-dialkylaminophenyl radical. If R * is an alkyl radical, this preferably has 1 to 7 carbon atoms.

'Typical advantageous photoconductors, which consist of polyarylalkanes and are used for the production of an electrophotographic Suitable recording material according to the invention are, for example, the photoconductors listed in Table B below:

909849/1233

Table B.

link No.

(1) ^ '- bis-CdiethylaminoW.Z'-dimethyltriphenylmethane;

(2) 4 ^1, 4 'diamino-4-diraethylamino ^l-2, 2 "-dimethyltriphenylraethan;

(3) 4 ^l, 4 "-bis (diethylamino) -2,6-dichloro-2 ^l, 2"-dimethyltriphenylijiethan;

(4) 4.4 "-bis (diethylamino) -2.2" -dimethyldiphenylnaphthylmethane;

(5) 2 ^l , 2 "-dimethyl-4,4 ^f , 4" -tris (dimethylamine) -triphenylmethane;

(6) 4 ^l, 4 "-bis (diethylamino) -4-dimethylamino-2 ^f, 2"-dimethyltriphenylmethane;

(7) 4 ·, 4 ^H -bis (diethylamino) -2-chloro-2 ·, 2 "-dimethyl-4-dimethylaminotriphenylmethane;

(8) 4 ^l, 4 "-bis (diethylamino) -4-dimethylamino-2,2 ^t, 2"-triraethyltriphenylmethan;

(9) 4 ·, 4 "-bis (dimethylamino) -Z-chloro-a ·, 2" -dimethyltriphenylmethane;

(10) 4 ^f , 4 "-bis (dimethylamine) -2 ^f , 2 ^H -dimethyl-4-methoxytriphenylmethane;

(11) 4,4-bis (benzylethylamino) -2,2 -dimethyltripheny! Methane;

(12) 4,4 ^ BiS (diethyl amino) -2,2 · diethoxytriphenylmethane;

(13) 4,4'-bis (dimethylamine) -1,1,1-triphenylethane;

(14) 1- (4-N, N-dimethylaminophenyl) -1,1-diphenylethane;

9098A9 / 1233

(15) 4-dimethylaminotetraphenylmethane and

(16) 4-Diethylaminotetraphenylmethane.

More advantageous photoconductors that can be used for manufacture of an electrophotographic recording material according to the invention are exemplified in the following USA patents described:

3,122,435; 3,127,266; 3,130,046; 3,131,060; 3,139,338;

3,139,339; 3,140,946; 3,141,770; 3,148,982; 3,155,503;

3,158,475; 3,161,505; 3,163,530; 3,163,531; 3,163,532;

3,169,060; 3,174,854; 3,180,729; 3,180,730; 3,189,447;

3,206,306; 3,141,770; 3,037,861; 3,041,165; 3,066,023;

3,072,479; 3,047,095; 3,112,197; 3,113,022; 3,114,633;

3,265,497; 3,274,000.

The photoconductor layer of the electrophotographic recording material according to the invention can consist of the photoconductor as well as the dye. "However, the photoconductor and dye are preferably dis * - pergates. However, the use of a binder is not absolutely necessary, and in particular not if if the photoconductor itself has film-forming properties, which for example in the case of poly (vinylcarbazole) the case is. However, a binder is preferably used to produce the photoconductor layer.

Suitable binders for producing the photoconductor layer are known. Suitable binders are those that have a have high dielectric strength and excellent insulating properties, at least in the absence of actinic radiation. Furthermore, they should have good film-forming properties. Typical for making an electrophotographic recording material according to the invention

909849/1233

suitable binders are polymers, for example polystyrene, Polymethylstyrene, styrene-butadiene copolymers, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, vinyl acetate-vinyl chloride copolymers, polyvinyl acetals, polyacrylic and polymethacrylic esters, polyesters, e.g. poly- (ethylene alkaryloxy-alkylene terephthalates), polycarbonate-formaldehyde, polycarbonate-formaldehyde.

For example, a polyester which has been produced from terephthalic acid and a glycolic mixture consisting of 9 parts by weight of 2,2-bis ^ "'4- (2-hydroxyethoxy) -phenyl _{(i <} 7propane) has proven to be a particularly advantageous binder and 1 part by weight of ethylene glycol.

The substrate of the recording material can be made of any * » one of the conventionally known electrically conductive supports used for the production of electrophotographic recording materials, for example a metal plate or a metal plate Metal foil or a layer carrier, consisting of a paper carrier or a film made of a plastic polymer, on which a metal foil has been laminated, or from an electrically conductive paper carrier or an electrically conductive film or from a paper carrier or a Foil that has been coated with a transparent, electrically conductive plastic. The support can furthermore have, for example, an electrically conductive layer consisting of a thin layer in a high vacuum deposited nickel or from a cuproiodide layer like them is described, for example, in U.S. Patent 3,245,833. The support can consist of a transparent, translucent or opaque material. If the recording material is to be exposed by reflex exposure, then the Support be translucent, whereas “such a requirement is not necessary when a“ projection exposure is carried out.

9098 4 9/123

Transparent supports are also required if the reproduction to be produced is used for projection purposes shall be. Translucent layers are preferably used for making reflective copies. Opaque substrates are then suitable if the image produced is then to be transferred to another layer support or if the The reproduction obtained is to be used in the manner obtained or when the reproduction is used as a printing plate or printing form to be used to make further copies.

The concentration of the cyanine dyes used according to the invention depends somewhat on the dye used in the individual case, the photoconductor used in the individual case and the desired Effects. Based on the weight of the photoconductor, the photoconductor layer can be 0.01 to 50, preferably 0.1 to 10 and in particular contain 1 to 10% by weight of cyanine dyes. On 1 to 75 parts by weight of photoconductor, based on the photoconductor layer, 25 to 99 parts by weight of binder can advantageously be dispensed with. In addition, in the photoconductor layer conventionally known other sensitizers, either spectrally sensitizing compounds or sensitivity enhancing compounds or both may be present.

Used to produce the photoconductive layer of the recording material If insulating binders of the invention are used, those are preferably used that reduce the surface resistance of the photoconductive layer is greater than 10 ohms per unit square (e.g., per square foot). Of the electrically conductive substrate should preferably have an electrical resistance of less than 10 ohms per square unit (e.g., per square foot).

The thickness of the photoconductor layer can vary widely be. Normally, the thickness of the photoconductor layer, measured in the dry state, is about 1 to 200 microns thick. Before-

909849/1233

ORIGINAL INSPECTED

preferably the phot ο leather layer when dry measured, a thickness of 3 to 50 microns.

The recording material is used to produce images Invention preferably initially kept in the dark (dark adaptation) and then either negative in the usual known manner or positively charged. The charging can be carried out, for example, by means of a corona discharge with a potential of about 6000 to 7000 volts. The charged recording material is then exposed in an image-correct manner, through an original, or reflex exposure in contact with an original, whereby an electrostatic image of the original is obtained. The invisible image obtained is then developed in the usual manner by means of a usual developing agent consisting of carrier and toner. The carrier can, for example, consist of small glass beads or particles of a plastic material or a Consist of iron powder. The toner can for example consist of a pigmented thermoplastic material with a grain size from about 1 to 100 μ exist, which is based on the to be developed Recording material can be fused, whereby the image can be made permanent. On the other hand, the developer can also suspend a pigment or pigmented resin contained in an insulating liquid, which may optionally contain a resin in solution. Is the polarity of the Charge of the toner particles opposite to the charge of the latent electrostatic image on the recording material, so becomes receive a record corresponding to the original. However, the polarity of the toner is the same as that of the latent one electrostatic image, a reverse image or a negative of the original is obtained

When using a recording material according to the invention visible images can be generated on this itself in the manner described. However, it is also possible to do either that first obtained latent, electrostatic image or the

909849/1233

wrapped image to transfer to a second support.

The following examples are intended to illustrate the invention in more detail.

Examples 1 to 6:

These examples illustrate the great increase in sensitivity of organic photoconductors when combined with the cyanine dyes used according to the invention can be used. The increase in sensitivity is based on the spectral sensitivity which is imparted to the photoconductors by adding the dyes used according to the invention. The examples also show that the sensitivity maxima or maxima Sensitization peaks ("Abs. Max.") Occur in most cases at around 350 to 625 nanometers. Some of the invention The dyes used also have more than just one maximum sensitivity, as can be seen from Table I below.

First, various solutions were prepared from 5.0 ml of methylene chloride as a solvent; 0.15 g of 4,4'-bis (diethylamino) -2,2'-dimethyltriphenylmethane as an organic photoconductor; 0.50 g Polyester, made from terephthalic acid and a glycol mixture of 2,2-bis ^ ~ 4- (2-hydroxyethoxy) p ^ henyl_7propane and ethylene glycol in a weight ratio of 9: 1 as a binder and 0.0065 g of a spectral sensitizing dye from Table A.

The solutions were then applied to aluminum layer ^{supports at 25 °} C. and dried onto the supports. All measures were carried out in a dark room. Samples of the recording materials obtained were then uniformly charged to a potential of about 600 volts by means of a corona discharge

/ "Consisting of a laminate of paper and an aluminum ^{£ olie} 909849/1233

and exposed through a transparent original with a pattern of different optical density by a tungsten lamp of 300O ^{0 K.}

The resulting electrostatic images were then developed by cascade development using a developer containing dispersed colored, thermoplastic, electrostatically responsive toner particles on glass beads. This developer was applied to the surface of the recording materials.

Apart from this type of development, you can do equally well with Success development methods can be used, for example, as described in U.S. Patents 2,786,439;

2,786,440; 2,786,441; 2,811,465; 2,874,063; 2,984,163;

3,040,704; 3,117,884; Re 25,779; 2,297,691 and 2,551,582 and in the journal "RCA Review" Volume 15 (1954), pages 469-484.

In the cascade development, as can be seen from Table I below, a visible image was produced in each case.

Further samples of the recording materials produced were tested for their electrical sensitivity and their maximum sensitivity, ie their maximum sensitivity. For this purpose, the electrostatic recording materials were charged positively or negatively, specifically with a corona discharge, until the surface potential, as measured by means of an electrometer sample, reached a potential of 600 volts. The recording materials were then mixed with a tungsten light source of 3000 ⁰ K with about 215 lux (20 foot candles) exposed. The exposure was carried out through a graduated gray wedge. The exposure resulted in a reduction in the surface potential of the recording material under each step

909849/1233

1 9 O A 6 2 9.

of the gray wedge from the original potential Vo to a lower potential V, the exact value of which differs from the irradiated The amount of light in meter-candle-seconds depends. The results of the Measurements were plotted in a diagram in which the surface potential V for each step versus the logarithm of Exposure was applied. The true sensitivity of any recording material is expressed in the reciprocal values of the exposure required to reduce the surface potential by 100 volts. As a result, η are the sensitivities reported in Table I below are the numerical values of 10 divided by the exposure in meter-candle-seconds that is required to reduce the 600 volt charge by 100 volts.

The results obtained are summarized in Table I below:

- 38 -

9098Λ9 / 123 3

dye
No. T a - 38 - 1 I. negative
loaded
Upper
area 904629 pictures
procreation bark Shoulder sensation
opportunities 7th without positive
loaded
Upper
area 200 example
No. XV Yes 8th 600 Sensation
opportunity XIX Yes 200 560 (Abs.max.)
nm. Ver
equal XXII Yes 1200 280 - 1 XXVI Yes 1100 40 440 2 XXIX Yes 320 250 39O; 45O; 615 3 XXIV Yes 90 39O; 615 4th Yes 370 420 5 mummm 6th 390; 440

From Table I it appears that with the use of the photoconductor alone, ie without Cyaninfabstoff, only sensitivities of 8 and were obtained 7 · Further, results from the table that, for example when using the dye XIX according to Example 2 sensitivities iron 1200 and 600 were achieved with positive or negative charging. The maximum sensitivity peaks were 390; 450 and 615 nanometers. This means an increase in sensitivity compared to the comparison sample by a factor of 150 in the case of the positively charged material and by a factor of 75 in the case of the negatively charged material. The expansion of the absolute sensitivity into the range of 615 nanometers is also of great importance. Even with the least effective cyanine dye of Example 5 (dye no. XXIX) there is still an extraordinarily favorable increase in the ' sensitivity by factors of * about 11 and 5 for the positively charged and negatively charged, respectively

909849/1233

- 39 material to be recorded.

Corresponding results as summarized in Table I were also obtained when, for example, the photoconductor used, namely 4,4'-bis (diethylamino) -2.2 ^l -dimethyltriphenylmethane, was replaced by another known photoconductor, for example 0.15 g triphenylamine, in in which case the dyes were used in the form of the p-toluenesulfonate salt, or if, for example, 1,3,5-triphenyl-2-pyrazoline or 2,3,4x5-tetraphenylpyrrole or 4,4'-bis-diethylaminobenzophenone was used as the photoconductor. The results obtained clearly show how effectively the dyes used according to the invention are able to spectrally sensitize a wide variety of organic photoconductors. The dyes used according to the invention are themselves not photoconductive.

Example 7 (comparative example) ;

This example shows that the achievable according to the invention It is not possible to achieve results with the previously customary known, spectral sensitizing dyes. The procedure described in Examples 1 to 6 was repeated, wherein but this time the dyes listed in Table C below were used as sensitizing dyes:

909849/1233

190A629

- 40 -, Table C

Dye name A pinacyanol B cryptocyanine C anhydro-3-ethyl-0-methyl-3 »- (3-sulfobutyl) -

thiacarbocyanine hydroxide

D 3,3'-Diethyl-9-methylthiacarbocyanine bromide E 3-carboxymethyl-S - / "(S-methyl-Z-thiazolidinyl ·

iden) -1-methylethyliden_ / rhodanine

F anhydro-5, S-dichloro-3,9-diethyl-3 - (3-sulfo-

butyl) thiacarbocyanine hydroxide

G 1 • -ethyl-S-methylthia-Z'-cyanine chloride H 1,1 »-diethyl-2 _t 2» -cyanine chloride

As already stated, the desensitize according to the invention dyes used are conventional negative photographic silver halide emulsions.

909849/1233

Claims (10)

- 41 -patent claims ί) Electrophotographic recording material, consisting of of a conductive layer support and at least one photoconductive layer applied to it with an organic photoconductor and a spectrally sensed photoconductor sensitizing cyanine dyes, characterized in that it contains a cyanine dye of the following structural formula as a spectral sensitizing dye: R, \ / C - * - ^R 4 where mean: L is an optionally substituted methine radical; Rj is an optionally substituted alkyl, alkenyl or aryl radical; R ₂ and R _{3 are} hydrogen atoms, alkyl radicals or optionally substituted aryl radicals; R _{4 is} an alkyl radical, an optionally substituted aryl radical or a radical of the formula ^ N 909849/1233 ORIGINAL WSPECTED where mean: ρ ■ 1 or 2 and Ζ «the atoms required to complete a 5- or 6-membered heterocyclic ring customary for cyanine dyes; m a 1 or 2; η = 2 or 3; X is an acid anion and Z is the one to complete a 5- or 6-membered heterocyclic which is customary for cyanine dyes Ring's Required Atoms " 2) electrophotographic recording material according to claim 1, characterized in that it contains a cyanine dye of the structural formula given, in which Z is the necessary to complete an electron accepting ring Represents atoms. 3) Electrophotographic recording material according to claim 2, characterized in that it contains a cyanine dye of the structural formula given, in which Z the to complete an optionally substituted thiazole; Oxazole-s selenazole-; Thiazoline-; Pyridine-; Quinoline; 3,3-dialkylindolenine-; Imidazole-; Imidazo ^ "4,5-b _- 7-quinoxaline-; 3,3'-dialkyl-3H-pyrrolo ^"'2,3-b _i- 7-pyi'idine- or a thi »2olo ^""4,5- b _g _7chino "represents linringes required atoms" 90 98 U 9/123 3 4) Electrophotographic recording material according to claim * - 2, characterized in that it is a cyanine dye Contains specified structural formula, in which Z is the completion of a substituted by a nitro radical Thiazole; Oxazole-; Selenazole-; Thiazoline-; Pyridine-; Chino-Hn-; 3,3-dialkylindolenine or imidazole ring represents the required atoms. 5) Electrophotographic recording material according to Claims 1 to 4, characterized in that it contains a cyanine dye of the structural formula given in which R ^ is a residue of the structural formula given in which Zj is the to complete an optionally substituted thiazole; Oxazole-; Selenazole-; Thiazoline-; Pyridine-; Chino-un-; 3,3-dialkylindolenine or imidazole ring represents the required atoms. 6) Electrophotographic recording material according to claim 4, characterized in that it is a cyanine dye contains given structural formula, in which Z is the completion of a nitrobenzothiazole; Nitrobenzoxazole or nitrobenzoselenazole ring represents required atoms. 7) Electrophotographic recording material according to Claims 1 to 6, characterized in that it is a triarylamine as the organic photoconductor; 1,3, S-triaryl-2-pyrazoline; 4,4'-bis (dialkylamino) -2,2 ^t -dialkyltriarylamin; Contains 2,3,4,5-tetraarylpyrrole or 4,4'-bis-dialkylaminobenzophenone. 8) Electrophotographic recording material according to claim 7, characterized in that it is triphenylamine as the organic photoconductor; 1,3,5-triphenyl-2-pyrazoline; 4,4 »-bis (diethylamino) -2,2'-dimethyltriphenylamine; Contains 2,3,4,5-tetraphenylpyrrole or 4,4 ^l -bis-diethylaminobenzophenone. 90984 9/1233 9) Electrophotographic recording material according to claims ΐ to 6, characterized in that it is a 1 _f 3-diallyl-2 - ^ 'i- (2-benzothiazolyl) -3,5-dimethyl-4-pyrazolyl_7-vinylJ -imidazo ^ as the cyanine dye ~ 4,5 ~ b_7quinoxalinium salt; 2 - / "(3,5-Dimethyl-1-phenyl-4-pyrazolyl) -vinyl_7-1» 3,3-trimethyl-3H-pyrrolo / ~ 2,3-b_7-pyridinium salt; 2-f (3,5 -Dimethy1-1-phenyl-4-pyrazoIyI) -vinyl_7-3-ethyIthiazolo- ^ "4,5-b _e 7-quinolinium salt; 3-ethyl-6-nitro-2- ^ ~ (1-phenyl-4-pyrazolyl) vinyl _- 7-benzothiazolium salt; 2 »£ ^" * 1- (2-Benzothiazolyl) -3, S-diBiethyl-4-pyrazolyl_7-vinylJ-3-ethyl-6-nitrobenzothiazolium salt or a 1,3-diallyl-2 - ^ "(1-phenyl- 4-pyrazolyl-vinyl _- 7-imidazo ^ "contains 4 _{liters of} 5-b_7-quinoxalinium salt. 10) Electrophotographic recording material according to claims 1 to 9j, characterized in that the photoconductive layer consists of a mixture of 1 to 75 parts by weight of an organic photoconductor, 99 to 25 parts by weight of a conventional binder and 0.01 to 10 parts by weight _s based on the weight of the mixture , a cyanine dye. ; i 09849/1233