DE1906797B2 - ELECTROPHOTOGRAPHIC RECORDING MATERIAL - Google Patents

Description

Il Il

R, ~ N ' ^? (= CH-CH) "_ ₁ = CL = LC CR ₅

N X

20th

contains in which R ₁ denotes an optionally substituted alkyl radical, an alkenyl radical or an optionally substituted aryl radical; R ₂ , R ₃ , R ₄ and R ₅ each represent a hydrogen atom, an alkyl radical or an optionally substituted aryl radical; L is an optionally substituted methine radical; n = 1 or 2; X is an anion and Z is the atoms required to complete a 5- or 6-membered heterocyclic ring customary for cyanine dyes. J ₀

2. Recording material according to claim 1, characterized in that it is a cyanine dye of the formula given contains, in which Z is the completion of an optionally substituted Thiazole, oxazole, selenazole, thiazo-Hn, pyridine, quinoline, 3,3-dialkylindolenine, Imidazole-, imidazo (4,5-b) quinoxaline-, 3,3-dialkyl-3 H-pyrrole (2,3-b) pyridine or a thiazole (4,5-b) quinoline ring means the atoms required.

3. Recording material according to claim 2, characterized in that it is a cyanine dye of the formula given, in which Z contains the one to be completed by a nitro group substituted thiazole, oxazole, selenazole, thiazoline, pyridine, quinoline, indole or Imidazole ringes means required atoms.

4. Recording material according to claim 1, characterized in that it is used as organic Photoconductor a triarylamine, a 1,3,5-triaryl-2-pyrazoline, contains a 2,3,4,5-tetraarylpyrrole or a 4,4'-bis-dialkylamino-benzophenone.

5. Recording material according to claim 1, characterized in that the photoconductive Layer of 1-75 parts by weight of photoconductor, 99-25 parts by weight of binder and 0.01-10 parts by weight of cyanine dye.

60

The invention relates to an electrophotographic recording material made of an electrically conductive one Layer support and at least one photoconductive layer with an organic Pholcitcr, one the Photoconductor, spectral sensitizing cyanine dye and optionally a binder.

It is known to use electrophotographic methods to produce images by the electrophotographic route To use recording materials, which consist of an electrically conductive substrate and a photoconductive insulating layer, the specific resistance of which is considerably higher in the dark than with irradiation of light. The recording materials are stored in the dark, the highest possible uniform resistance in the photoconductive, insulating To bring about a layer, whereupon they are electrostatically charged negatively or positively in the dark.

The recording materials can then be exposed in an imagewise manner, with the resistance the photoconductive layer is reduced imagewise according to the intensity of the amount of irradiated light will. In this way a latent, electrostatic image is obtained from which a visible image for example by dusting a finely powdered, meltable pigment, the particles of which have a carry electric charge which is opposite to the charge of the recording material can be obtained can. The pigment particles can then be fused firmly with the photoconductive Layer to be connected.

A wide variety of photoconductors are used for the production of electrophotographic recording materials known. Typical inorganic photoconductors are, for example, selenium and zinc oxide. Such Inorganic photoconductors, however, have the disadvantage that they are not suitable for the production of recording materials suitable for reflex copier systems and that, when used in conjunction with Do not allow images to be produced on transparent substrates, unless via detours.

When using organic photoconductors, these disadvantages can be avoided. The known However, organic photoconductors again have the disadvantage that their sensitivity to visible radiation is relatively low. It is therefore known e.g. From US-PS 31 74 854 and 30 41 165 and GB-PS 9 64 873, the spectral sensitivity of organic photoconductors by adding certain Cyanine or merocyanine dyes, for example by such dyes as they are in the Table C below will be listed later. However, it has been shown that when using the spectral sensitivity caused by such dyes is very low.

It has also already been proposed (cf. DT-PS 19 04 629) for spectral sensitization organic photoconductor to use cyanine dyes with a 4-pyrazolyl radical.

The object of the invention is to provide an electrophotographic recording material whose photoconductive layer is effectively spectrally sensitized.

It has been found that cyanine dyes are excellent for sensitizing organic photoconductors are suitable if they consist of a first and a second 5- or 6-membered nitrogen containing are built up heterocyclic ring, which are connected to one another via a methine radical, with the proviso that the first ring consists of a pyrrole ring bonded to the methine residue via its 2-carbon atom and the second ring is a ring typical of cyanine dyes, preferably one that accepts electrons Is a ring that is bonded to the methine residue via one of its carbon atoms.

The subject matter of the invention is thus based on an electrophotographic recording material of an electrically conductive substrate and at least one photoconductive layer with a jrganic photoconductor, a cyanine dye peat which "spectrally" sensitizes the photoconductor, and possibly a binder and is characterized in that it is a cyanine dye of the formula

..-- Z- ^ R ₃ -C CR ₄

ii ii

R _r N ^ = CH-CH) "_, = CL = LC CR,

I (D

contains where R ₁ denotes an optionally substituted alkyl radical, an alkenyl radical or an optionally substituted aryl radical; R ₂ , R ₃ , R ₄ and R ₅ each represent a hydrogen atom, an alkyl radical or an optionally substituted aryl radical; L is an optionally substituted methine radical; η = 1 or 2; X is an anion and Z is the atoms required to complete a 5- or 6-membered heterocyclic ring customary for cyanine dyes.

The cyanine dyes used for the production of the recording materials according to the invention have the property that they are incorporated into a negative gelatin - silver bromide iodide emulsion with 99.35 mol percent bromide and 0.65 mol percent iodide in a concentration of 0.2 millimoles of dye per mole of silver halide Desensitize the emulsion by more than 0.4 log Ε units if the test emulsion is exposed through a step wedge after application to a conventional substrate, exposed in a sensitometer (to achieve D _max ) to light with a wavelength of 365 nanometers and exposed for 3 minutes at 20 ⁰ C in a developer 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 1 with water

developed and finally fixed, watered and dried in the usual way.

The silver bromide iodide negative emulsion used in the test is made as follows:

A solution (A) of 165 g of potassium bromide, 5 g of potassium iodide, Bring 65 g of gelatin and 1700 ml of water to a temperature of 54 ° C.

A filtered solution (B) of 200 g of silver nitrate and 2000 ml of water is also placed in a separatory funnel heated to 54 "C. The silver nitrate solution is then from the separating funnel through a calibrated nozzle into the container containing the solution (A) allowed to run with the contents of the container during the precipitation of the silver halide and the ripening is constantly moving. The precipitation of the silver halide takes place over a period of 10 minutes.

The cyanine dyes desensitize common negative <\ s tive silver halide emulsions which are sensitive to blue radiation. The ver dyes according to the invention reduce this sensitivity and cause practically no spectral sensitization such emulsions. In view of this, it was surprising to find that the same dyes able to spectrally sensitize organic photoconductors.

Another characteristic of the cyanine dyes described is that they are practically non-photoconductive are. By "practically non-photoconductive" it is meant that no image is produced when a solution of 0.002 g of the dye and 0.5 g of polyester binder (used in Examples 1 to 5 below) specified composition) to be dissolved in 5.0 ml of methylene chloride and if this solution on a support is applied in the absence of a photoconductor and when the recording material produced is tested in the manner described in more detail in Examples 1 to 5 below will be.

The invention achieves that recording materials with organic photoconductors are available in which the responsiveness the photoconductor is raised to rays in the range of 400 to 700 nanometers. The cyanine dyes act as sensitizing dyes. Will they work together with organic photoconductors is used whose sensitivity is low or insufficient, the cyanine dyes act both as compounds that increase sensitivity as well as spectral sensitizers.

In the formula I, the methine radical represented by L can, for example, be replaced by an alkyl radical preferably 1 to 12 carbon atoms or an aryl radical, preferably of the phenyl or naphthyl series, be substituted, d. H. L can be a methine residue of the formulas

-CH =

-C (CH ₃ ) = or -C (C ₆ H ₅ ) =

If R _{1 is} an optionally substituted alkyl radical, this preferably has 1 to 12, in particular 1 to 4, carbon atoms. The alkyl radical can be an aliphatic or cycloaliphatic radical. R ₁ is, for example, a methyl, ethyl, propyl, isopropyl, butyl, hexyl, cyclohexyl, decyl or dodecyl radical. If R _{1 is} a substituted alkyl radical, this can be, for example, a hydroxyalkyl radical, e.g. B. a / 9-hydroxyethyl or ω-hydroxybutyl radical, or an alkoxyalkyl radical, e.g. B. a 0-Methoxyäthyl- or ω-Butoxybutylrest, or a Carboxyalicylrest, z. B. a ß-Catb oxyäthyl- or ω-Carboxybutylrest, or a sulfoalkyl radical, z. B. a / I-sulfoethyl or ω-sulfobutyl radical, or a sulfatoalkyl radical, z. B. a / 3-sulfatoethyl or i /) - sulfatobutyl radical, or an acyloxyalkyl radical, e.g. B. a / i-acetoxyethyl, γ-acetoxypropyl or ω-butyryloxybutyl, or an alkoxycarbonylalkyl, z. B. a / i-Methoxycarbonyläthyl- or ω-Äthoxycarbonylrest, or an aralkyl radical, z. B. a benzyl or phenethyl radical.

If R _{1 is} 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 R _{1 has} the meaning of an optionally substituted aryl radical, this preferably consists of an optionally substituted aryl radical of the phenyl or naphthyl series, ie R ₁ can, for example

a phenyl, ToIyI, naphthyl, methoxyphenyl or Be chlorophenyl radical.

If R ₂ , R ₃ , R ₄ and R ₅ are alkyl radicals, then these preferably have 1 to 12, in particular 1 to 4, carbon atoms and consist, for example, of methyl or ethyl. Propyl, isopropyl, butyl, decyl or dodecyl radicals. If R ₂ , R3, R ₄ and R ₅ are optionally substituted aryl radicals, these preferably consist of aryl radicals of the phenyl or naphthyl series, ie for example phenyl, tolyl, naphthyl, methoxyphenyl, chlorophenyl or nitrophenyl radicals.

X is an anion as found in known common cyanine dyes; H. for example a chloride, Bromide, iodide, perchlorate, sulfamate, thiocyanate, p-toluenesulfonate or methyl sulfate anion.

The 5- or o-membered heterocyclic ring completed by Z may also necessarily present nitrogen atom also have a further second heteroatom, d. H. for example an oxygen, sulfur, selenium or nitrogen atom.

For example, Z represents the atoms necessary to complete a thiazole, 4-methylthiazole; 4-phenylthiazole-; 5-methylthiazole-; 5-phenylthiazole-; 4,5-dimethylthiazole-; 4,5-diphenylthiazole-; 4- (2-thienyl) thiazole-; Benzothiazole; 4-chlorobenzothiazole; 4- or 5-nitrobenzothiazole; 5-chlorobenzothiazole-; 6-chlorobenzothiazole-; 7-chlorobenzothiazole-; 4-methylbenzothiazole-; 5-methylbenzothiazole-; 6-methylbenzothiazole-; 6-nitrobenzothiazole-; 5-bromobenzothiazole-; 6-bromobenzothiazole-; 5 - chloro - 6 - nitrobenzothiazole; 4 - phenylbenzothiazole-; 4-methoxybenzothiazole-; 5-methoxybenzothiazole-; 6-methoxybenzothiazole-; 5-iodobenzothiazole-; 6-iodobenzothiazole-; 4-ethoxybenzothiazole-; 5 - ethoxybenzothiazole; Tetrahydrobenzothiazole-; 5,6-dimethoxybenzothiazole-; 5,6-dioxymethylene benzothiazole; 5-hydroxybenzothiazole-; 6-hydroxybenzothiazole-; Naphtho [2.1-d] thiazole-; Naphtho [1,2-d] -thiazole-; Naphtho [2,3-d] thiazole-; 5-methoxynaphtho- [2,3 - d] thiazole-; 5 -ethoxynaphtho [1,2-d] thiazole-; 8-methoxynaphtho [2, l-d] thiazole-; 7-methoxynaphtho [2, l-d] thiazole-; 4'-methoxythianaphtheno-7 ', 6', 4,5-thiazole or one substituted by a nitro radical Naphthothiazole ring;

an oxazole; 4-methyloxazole-; 4-nitrooxazole-; 5-methyloxazole-; 4-phenyloxazole-; 4,5-diphenyloxazole-; 4-ethyloxazole-; 4,5-dimethyloxazole-; 5-phenyloxazole-; Benzoxazole-; 5-chlorobenzoxazole-: 5-methylbenzoxazole-; 5-phenylbenzoxazole-; 5- or 6-nitrobenzoxazole-; S-chloro-o-nitrobenzoxazole-; 6-methylbenzoxazole-; 5,6-dimethylbenzoxazo! -; 4,6-dimethylbenzoxazole-; 5-methoxybenzoxazole-; 5-ethoxybenzoxazole-; 5-chlorobenzoxazole-; 6-methoxybenzoxazole-; 5-hydroxybenzoxazole-; 6-hydroxybenzoxazole-; Naphtho [2,1 -d] oxazole-; Naphtho [1,2-d] oxazole or a naphthoxazole ring substituted by a nitro radical;

a selenazole; 4-methylselenazole-; 4-nitroselenazole-; 4-phenylselenazole-; Benzoselenazole 5-chlorofto benzoselenazole 5-methoxybenzoselenazole-; 5-hydroxybenzoselenazole-; 5- or 6-nitrobenzoselenazole-; S-chloro-o-nitrobenzoselcnazole-; Tetrahydrobenzoselenazole-iii-naphthoselenazole-j / i-naphthoselcnazole or cr a naph- <> thoselcnazole ring substituted by a nitro radical;

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

a pyridine; 2-pyridine-; 5-methyl-2-pyridine-; 4-pyridine-; 3-methyl-4-pyridine or one through a nitro radical substituted pyiidine ring;

a quinoline ring, e.g. a 2-quinoline; 3-methyl-2-quinoline-; 5-ethyl-2-quinoline-; 6-chloro-2-quinoline-; 6-nitro-2-quino! In, 8-chloro-2-quinoline-; 6-methoxy-2-quinoline-; 8-ethoxy-2-quinoline-; 8-hydroxy-2-quinoline-; 4-quinoline-; 6-methoxy-4-quinoline-; 6-nitro-4-quinoline-; 7-methyl-4-quinoline-; S-chloro ^ -quinoline-; 1-isoquinoline-; 6-nitro-l-isoquinoline - ^^ - dihydro-l-isoquinoline or S-isoquinoline linringes;

a 3,3-Dialkylindoleninringes with preferably a nitro or cyano substituent, e.g. B. a 3,3-dimethyl-5- or 6-nitroindolenine; 3,3-dimethyl-5- or 6-cyanoindolamine ring;

of an imidazole-; l -alkylimidazole-; alkyl-4-phenyI-imidazole-; 1-alkyl- ^ S-dimethylimidazole-; Benzimidazole-; 1-alkylbenzimidazole-; 1-alkyl-5-nitrobenzimidazole-; l-aryl-S.o-dichlorobenzimidazole-; 1-alkyl-1H-naphthimidazole-; 1-aryl-JH-naphthimidazole-; 1-A1-alkyl-5-methoxy-1 H-naphthimidazole ring or

an imidazo [4,5-b] quinoxaline ring, e.g. A 1,3-dialkylimidazo [4,5-b] quinoxaline ring, e.g. B. one 1,3 - diethylimidazo [4,5 - b] quinoxa! In; 6 - chlorol, 3-diethylimidazo [4,5-b] quinoxaline ring or a 1,3-dialkenylimidazo [4,5-b] quinoxaline ring, e.g. B. a 1,3 - diallylimidazo [4,5 - b] quinoxaline or 6 - chloro - 1,3 - diallylimidazo [4,5 - b] quinoxaline ring or a 1,3-diarylimidazo [4,5-b] quinoxaline ring, z. B. a 1,3-diphenylimidazo [4,5-b] quinoxaline ring;

a 3,3-dialkyl-3 H-pyrrole [2,3-b] pyridinrinues, e.g. B. a 3,3-dimethyl-3 H-pyrrole [2,3-b] pyridine-o "der 3,3-Diethyl-3H-pyrrole [2,3-b] pyridine ring or a thiazole [4,5-b] quinoline ring.

According to an advantageous embodiment of the invention, the recording material contains a Cyanine dye of the formula given in which Z is the one to complete an optionally substituted Thiazole; Oxazole-; Selenazole-; Thiazoline-; Pyridine-; Quinoline; 3,3-dialkylindolenine-; Imidazole-; Imidazo [4,5-b] quinoxa! In; 3,3-dialkyl-3 H-pyrrole [2,3-b] pyridine or a thiazolo [4,5-b] quinoline ring represents required atoms.

This configuration ensures that AuI drawing materials are available in which the response of the photoconductor to rays ranges from 400 to 700 nanometers is particularly greatly increased.

Particularly advantageous cyanine dyes are also those in which Z is used to complete an in Cyanine dyes usual 5- or 6-membered heterocyclic, nitrogen-containing ring with a represents atoms required by a carbon atom substituted by a nitro group.

According to an advantageous embodiment of the invention, the recording material contains a cyanine dye of the formula given, in the Z door the one substituted by a nitro group to complete one Thiazole, oxazoK, selenazole, thiazoline, l-yridine, quinoline, indole or imidazole ring Atoms stands.

This embodiment of the invention also creates recording materials in which the response of the photoconductors to rays in the range of 400 to 700 nanometers is particularly greatly increased.

Those dyes of the formula I have also proven to be particularly advantageous in which Z is the one for completion of an electron accepting ring represents the required atoms, e.g. B. the already mentioned dyes with one through a nitro group substituted ring and dyes with an imidazof / l ^ -blquinoxaline, 3,3-dialkyl-3 H-pyrrole- [2,3-b] pyridine- or thiazolo [4,5-b] quinoline ring.

As an electron accepting or acccpticrender ring a ring is to be understood, which after transfer into a symmetrical carbocyanine dye and adding it to a gelatin-silver chlorobromide emulsion with 40 Mole percent chloride and 60 mole percent bromide in a concentration of 0.01 to 0.2 g Dye per mole of silver by electron uptake results in at least an 80% loss of blue sensitivity the emulsion when exposed sensitometrically and for 3 minutes in a developer of the composition already given is developed at 20 ° C. Particularly advantageous electrons Receiving rings are those that are converted into a symmetrical carbocyanine dye and testing the same in the manner described for a practically complete desensitization the test emulsion lead to blue radiation. As a practically complete desensitization this means that the emulsion is at least 90%, preferably 95%, its sensitivity to blue radiation is lost.

The cyanine dyes which can be used for the production of recording materials according to the invention given formula I can be easily produced. A suitable method of making the same consists in a heterocyclic compound of the following structural formula II:

R ₁ - N (= CH -CH) "., - · ■ · CR

(ID

R-C-

-CR ₄

Il
CR,

(HI)

in which R ₂ , R ₃ , R ₄ and R _{5 have} the meaning already given, to react with one another at temperatures of about 15 "C. to the reflux temperature of the mixture. for example a trialkylamine, for example triethylamine, or piperidine or N-methylpipendine in an inert solvent, for example an alkanol, for example ethanol or acetic anhydride.

Chain-substituted dyes can be produced when R is ethyl, benzyl or the like Rest is. The crude dyes obtained during the implementation of the two components can

35

where π, R ₁ , X and Z have the meaning already given and R is a methyl, ethyl, benzyl or similar radical, with a pyrrole compound of the following structural formula IH:

isolated from the reaction mixture by customary processes and by recrystallization one or more times from suitable solvents, for example methanol or mixtures of dimethylacetamide and methanol can be cleaned.

The intermediate compounds of the formula III required for the preparation of the cyanine dyes can be also easy to manufacture. A suitable method consists in practically equimolar amounts of a Compound of formula IV

HC

CR ₅

(IV)

wherein R ₂ , R ₃ , R ₄ and R _{5 have} the meaning already given, with a Ν, Ν-dimethylformamide / phosphoryl chloride complex in an inert solvent medium, such as. B. dichloroethane to implement. The procedure is preferably such that the N, N-dimethylformamide / phosphoryl chloride complex with the solvent medium, e.g. B. dichloroethane, is stirred while the pyrrole compound is slowly added to this in the form of a solution in dichloroethane at ice bath temperature. The mixture can then be heated to reflux temperature for a short period of time. It is then cooled, whereupon an aqueous solution of sodium acetal is added. After further heating under reflux conditions, the crude reaction product can be isolated by decanting or extraction methods. The pure compound can then be obtained by recrystallization of the crude reaction product from a suitable solvent, e.g. ligroin.

Further information on the preparation of the dyes can be found, for example, in DT-PS 18 (K) 421.

Typical advantageous dyes that can be used in the manufacture of the recording material of the invention are the dyes given in the following table Λ:

Table A.

! ■ "arhsliif! Vci-ΙιιηιΙιιημ 5 "No.

55

(\ 0 3-Ethyl-6-nitro-2 "[2- (2-pyrrolyl) vinyl] -benzothiazolium-p-toluenesulfonate der formula

1.3.3-Trimethyl-5-nitro-2- [2- (2-pyrrolyl) vinyl] -3H-indolium p-loluenesulfonate

3-Ethyl-2- [2- (1-methyl-2-pyrrolyl) vinyl] -6-nitrobenzothiazolium-p-toluenesulfonut

709627/33

5

continuation

Dye compound
No.

IV 1,3,3-trimethyl-2- [2- (1-methyl-2-pyrrolyl) vinyl] -5-nitro-3 H-indolium iodide

V 3-Ethyl 2- [2- (5-methyl-2-pyrrolyl) vinyl] -6-nitrobenzothiazolium p-toluenesulfonate

VI 3-Ethyl-6-nitro-2- [2- (1-phenyl-2-pyrrolyl) vinyl] benzothiazolium perchlorate

VII 1,3-diethyl 2- [2- (1-phenyl-2-pyrrolyl) vinyl] imidazo [4,5-b] quinoxalinium perchlorate

VIII 1,3,3-Trimethyl-5-nitro-2- [2- (I -p-nitrophenyl-2-pyrrolyl) vinyl] -3H-indolium-p-toluenesulfonate

IX 1,3-Diethyl-2- [2- (1-p-nilrophynyl-2-pyrrolyl) vinyl] imidazof4,5-b] quinoxalinium iodide

X 2- [2- (1,5-diphenyl-2-pyrrolyl) vinyl] -3-ethyl-6-nitrobenzothiazolium perchlorate

XI 2- [2- (1,5-Diphenyl-2-pyrrolyl) vinyl] -1,3,3-trimethyl-5-nitro-3H-indolium perchlorate

XII 2-f2- (1,5-diphenyl-2-pyrrolyl) vinyl] 1,3-diethylimidazo [4,5-b] quinoxalinium perchlorate

For example, dye I of Table A can be prepared as follows:

7.9 g of 3-ethyl-2-methy] -6-nitrobenzothiazolium p-toluenesulfonate, 1.9 g of pyrrole-2-carboxaldehyde and 3 drops of piperidine were dissolved in 25 ml of ethanol, whereupon the solution was heated to reflux with stirring for 5 minutes. After cooling down the precipitated dye was filtered off, washed with ethanol and dried. The yield of the crude dye was 5.9 g, corresponding to 78% of theory. After a one-time Umkrislallisalion from methanol, 3.5 g of pure dye corresponding to 46% of theory with a melting point from 254 to 255 ° C (dec.).

Other advantageous dyes for manufacture of the photographic recording material according to the invention are, for example:

3-ethyl-2- [2- (l-methyl-2-pyrrolyl) vinyl] -

6-nitrobenzoxazolium salts, 3-ethyl-2- [2- (1-methyl-2-pyrrolyl) vinyl] -

6-nitrobenzoselenazolium salts, 3-ethyl-6-nitro-2- [2- (l-phenyl-2-pyrrolyl) vmyl] -

benzoxazolium salts.

3-ethyl-6-nitro-2- [2- (l-phenyl-2-pyrrolyl) vinyl] -

benzoselenazolium salts,

3-phenyl-6-nitro-2- [2- (l-phenyl-2-pyrrolyU-

vinyl] benzothiazolium salts,

1,3-diallyl-2- [2- (1-phenyl-2-pyrrolyl) vin yl] -

imidazo [4,5-b] quinoxalinium salts,

1,3-diphenyl-2- [2- (1-phenyl-2-pyrrolyl) vinyl] -

imidazo [4,5-b] quinoxalinium salts,

2- [2- (1,5-diphenyl-2-pyrrolyl) vinyl] -1,3-diallyl-

imidazo [4,5-b] quinoxalinium salts and

2- [2- (1,5-diphenyl-2-pyrrolyl) vinyl] -1,3-diphe-

nylimidazo [4,5-b] quinoxalinium salts.

namely in the form of chlorides, bromides, iodides, perchlorates, p-toluenesulfonates and the like.

Other particularly advantageous cyanine dyes for the production of the electrophotographic recording material of the invention are those of the formula I given, in which Z is the completion of a sensitizing ring, i.e. for example 3-ethyl-2- [2- (1-methyl-2-pyrrolyl) vinyl] benzothiazolium salts; 3-Ethyl-2 - [2 - (1 - methyl - 2 - pyrrolyl) vinyl] benzoxazolium salts as well as 3-ethyl-2- [2- (l-methyl-2-pyrrolyl) vinyl] -benzoselenazolium salts, for example, in turn, the chlorides, bromides, iodides, perchlorates. p-toluenesulfonates and the like.

For the production of the electrophotographic recording material According to the invention, one of the specified dyes can be used or else several of the specified dyes can be used at the same time. The electrophotographic recording material according to the invention can further contain one or more different, conventionally known, organic photoconductors. For this include the so-called monomeric as well as the so-called polymeric organic photoconductors. As already stated, the cyanine dyes used according to the invention are particularly suitable for increasing the sensitivity of organic photoconductors, which are not very sensitive or practically insensitive are or have only a low sensitivity, d. H. a sensitivity of less than 25, generally less than 10 when following the procedure described in Examples 1 to 5 below be tested for their sensitivity to radiation from 400 to 700 nanometers.

Particularly advantageous organic photoconductors have proven to be those which are used as organic photoconductors of the amine type have become known. There is a common feature of such photoconductors in that they have at least one amino radical.

Photoconductors suitable for producing the photoconductive recording material according to the invention are therefore, for example, arylamine, e.g. B. (I) diarylamines, e.g. B. Diphcnylamin, Dinaphthylamin, Ν, Ν'-Diphenylbenzidin, N-Phcnyi-1-naphthylamin; N-phenyl-2-naphthylamine; Ν, Ν'-diphynyl-p-phynylcndiamine;2-carboxy-5-chloro-4'-methoxydiphenylamine;p-anilinophenol; N, N'-di-2-naphthyl-p-phenylenediamine;4,4'-benzylidene-bis (N, N-diethyl-m-toilidine), the arnim and the like known from US Pat. No. 32 40 597, and (2) triarylamines. namely (a) non-polymeric triarylamines, e.g. B. triphenylamine; NNN'.N'-telraphenyl-m-phenylenediamine; 4 - acetyl triphenylamine; 4 - hexanoyl triphenylamine; 4 · lauroyl triphenylamine; 4 ■ hexyltriphynylamine; 4-dodecyltriphenylamine; 4,4'-bis (diphenylamino) benzil; 4,4'-bis (diphenylamino) benzophenone and the like, such as (b) polymeric triarylamines, e.g. B. Poly [N, 4 "- (N, N ', N'triphenylbenzidine)]; polyadipyl triphenylamine; blihli Pldhlih

py)]; ydpypy polysebacyl triphenylamine; Polydecamethylene triphenylamine; Poly-N- (4> v! Nylphenyl) dipnenylamine; Poly N- (vinylphenyl) - «, flc'-dinaphthylamine and the like.

Other useful amine-type photoconductors are disclosed, for example, in U.S. Patent 318073C described.

Further advantageous photoletter, which can be used for Her position of the electrophotographic recording ^ material according to the invention are suitable for

5

for example in the USA.-Patent 32 65 496 described. Such photoconductors include those of the following structural formula:

N / A -

A '

Herein means

A a mononuclear or polynuclear, divalent, aromatic, either condensed or linear remainder, ζ. B. a phenylene, naphthylene, biphenylene or binaphthylene radical or a substituted, divalent, aromatic radical of this type, it being possible for the substituent or substituents to consist of z. B. acyl radicals with 1 to about 6 carbon atoms, ζ. B. acetyl, propionyl or butyryl radicals, or Alkyl radicals with 1 to 6 carbon atoms, ζ. Β. Methyl, ethyl, propyl or butyl radicals, or alkoxy radicals with 1 to 6 carbon atoms, ζ. Β. Methoxy, ethoxy, propoxy or pentoxy radicals, or nilro radicals;

A 'a mononuclear or polynuclear monovalent, aromatic, either condensed or linear remainder, ζ. B. a phenyl, naphthyl or biphenyl radical, or a substituted monovalent, aromatic radical of this type, the substituent or substituents of which may exist, for example from acyl radicals with 1 to 6 carbon atoms, ζ. Β. Acetyl, propionyl or butyryl radicals, or alkyl radicals with I to 6 carbon atoms, ζ, Β. Methyl, ethyl, propyl or butyl radicals, or alkoxy radicals with 1 to 6 carbon atoms, ζ. Β. Mclhoxy, propoxy or pentoxy radicals, or nitro radicals;

Q represents a hydrogen atom, a halogen atom or an aromatic amino radical, e.g. B. the formula A'NH, wherein A 'has the meaning already given;

/> a number from I to 12 and

G is a hydrogen atom, a mononuclear or polynuclear aromatic, either condensed -ίο or linear remainder, ζ. B. a phenyl, naphthyl or Biphcnylrcst. or a substituted aromatic A radical whose substituent or substituents can consist, for example, of an alkyl, alkoxy, Acyl or a nitro radical, or a poly (4'vinylphcnyl) radical attached to the nitrogen atom through a carbon atom of the Phcnylrcstcs is bound.

Nitrogen-containing, heterocyclic compounds, for example compounds such as 1,3,5-tryphynyl-2-pyrazoline and 2,3,4,5-tetraphenylpyrrole, are also suitable for the production of the clckrophotographic AuI '- / eicluumgsmaterials according to the invention.

Have been found to be particularly advantageous for production of the recording material according to the invention proved organic photoconductors, which are made of polyurylalkylenes ss exist. Such photoconductors are described, for example, in U.S. Pat. No. 3,274,000, US Pat French patent 13 83 461 and Belgian patent 696 114.

Leucobus from fio belong to such photo conductors Diaryl and triaryl methane dye salts; 1,1.1-Triurylalkunc, in which the alkane rust at least two Has carbon atoms, as well as telraarylmelhane. where of these compounds at least one aryl radical which is bonded to the alkane radical or to the fts Mcthanrest, is substituted by an amino radical. The two last-mentioned classes of photoconductors do not consist of leuco bases.

Particularly advantageous for the production of the electrophotographic Recording material according to the invention leave suitable polyarylalkane photoconductors represented by the following structural formula:

R "

R'-C-R '"

Herein R ", R '" and R "" mean aryl radicals and R' a hydrogen atom, an alkyl radical or an aryl radical, with the proviso that at least one of the radicals R ", R '" and R "" have an amino substituent.

The aryl radicals that are 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, e.g. B. by alkyl and alkoxy groups with preferably 1 to 8 carbon atoms, hydroxy radicals or halogen atoms, these substituents being in the o-, m- or p-position. As special photoconductors with o-substituted ones have proven advantageous Phenyl residues proved.

The aryl radicals can optionally also be linked to one another or cyclized, in which If they can, for example, form a fluorene residue. The amino substituent can be represented by the following Represent structural formula:

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

Typical advantageous photoconductors, which consist of polyarylalkunene and are used for the production of the electrophotographic recording material according to the The photoconductors listed in Table B below are, for example, suitable for the invention:

Table B.

link

(1) 4,4'-bis (diethylamino) -2,2'-dimethyltriphenylmethane

(2) 4 ', 4 "-Diamino-4-dimethylamino-2', 2" -dimethyltriphenylmelhane

Fortselzuni;

link No.

(3) 4 \ 4 "-bis (diethylamino) -2,6-dichloro-2 ', 2" -dimethyltriphenylmethane

(4) 4 \ 4 "-bis (diethylamino) -2 ', 2" -dimethyldiphenylnaphthylmethane

(5) 2 \ 2 "-Dimethyl-4,4 ^/ , 4" -tris (dimethylamino) -triphenylmethane

(6) 4 ', 4 "-bis (diethylamino) -4-dimethylamino-2', 2" -dimethyltriphynylmethane

(7) 4 ', 4 "-bis (diethylamino) -2-chloro-2', 2'-dimethyl-4-dimethylaniinotriphenylmethane

(8) 4 \ 4 "-bis (diethylamino) -4-dimethylamino-2,2 ', 2" -trimet hy Itripheny! methane

(9) 4 \ 4 "-bis (dimethylamino) -2-chloro-2 \ 2" -dimethyltriphenyliticthane

(K)) 4 ', 4 "-bis (dimethylamino) -2', 2" -dimethyl-4-methoxytriphenylmcthane

(I I) 4,4'-bis (benzylethylamino) -2,2'-dimethyl

triphenylrrethane

(12) 4,4'-bis (diethylamino) -2,2'-dietho \\ lriphynylmethane

(13) 4,4'-bis (dimethylamino) -1,1,1-triphenylethane

(14) 1- (4-N, N-Oimclhylaminophcnyl) -1,1 -diphenyläthan

(15) 4-Dimethylaminotetraphynylmethane

(16) 4-Diethylaminotetraphenylmelhan

Further photoliter, which can be used for the production of the clcktrophotographischcn Auf / eich mmgsiruiicria Is are suitable according to the invention, for example in the following U.S. patents:

31 22 435;
31 39 338;
3! 48,982;
31 63 530;

31 74 854;

32 06 306;

30 66 023;

31 13 022;

32 74 (MM).

3,127,266;
31 39 339;
31 55 503;
31 63 531;
31 80 729;
31 41 770;

30 72 479;

31 14 633;

31 30 046; 31 40 946; 31 58 475; 31 63 532;

31 80 730; 30 37 861: 30 47 095:

32 65 497

31 31 060: 31 41 770; 31 61 505; 31 69 060: 31 S9 447:

30 41 165:

31 12 197; and

The photoconductor layer of the electrolytic recording material according to the invention can consist of the photoconductor and the dye. Preferably, however, the photoconductor and dye are dispersed in a binder. However, the use of a binder is not absolutely necessary and / was not particularly thin if the photoconductor itself has film-forming properties. An example of such a (transforming photoconductor is, for example, polyvinyl carbazole). However, a binder is preferably used to produce the photoconductor layer.

Suitable binders for producing the photoconductor layer are known. Suitable binders are those which have high dielectric strength and excellent insulating properties, at least in the absence of uctinic radiation, as well as good reshaping properties. Typical binders suitable for producing the electro-photographic recording material according to the invention are polymers such as polystyrene, polymethylslyrole, slyrole-butadicne copolymers, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, vinyl acetate-vinyl chloride copolymers. Polyvinyl acetate. Polyacrylic and polymethacrylic esters, polyesters, e.g. B. poly (ethylene alkaryloxy-alkylene terephthalate), phenol-formaldehyde resins, polyamides, polycarbonates and the like.

The support of the recording material according to the invention can be made of any of the usual known, electrically conductive used for the production of electro-photographic recording materials Carriers exist, e.g. B. consisting of a metal plate or a metal foil or a layer support from a paper carrier or from a film made of a plastic polymer, on the or the a metal foil is laminated on, or from an electrically conductive paper carrier or an electrically conductive film or from a paper carrier or a film that or which is covered with a transparent, electrically conductive plastic has been coated. The layer support can furthermore be an electrical one Have conductive layer, consisting of a thin layer of nickel applied in a high vacuum or from a cuproiodide layer, as described, for example, in US Pat. No. 3,245,833 will. The substrate can be made of a transparent, consist of translucent or opaque material. Should the recording material be exposed by reflex exposure the support must be translucent, whereas such a requirement does not exist, if a projection exposure is to take place Transparent substrates are finer then necessary, if the reproduction to be made is to be used for door projection purposes. Translucent Layer supports are preferably used for the production of copies. Opaque substrates are suitable when the image produced is then transferred to another layer support should or if the reproduction obtained is to be used in the manner obtained or if the Reproduction is to be used as a printing plate or printing form for making multiple copies

The concentration of the cyanine dye used in accordance with the invention depends somewhat on the dye used in the individual case, the photoconductor used in the individual case and the effects desired. It has proven to be advantageous, based on the weight of the photoliter, to be about 0.1 to 50%. preferably 1 to 10% to use dye. The photoconductor-binder layer can thus, for. B. consist of about 1 to 75 parts by weight of photoconductors. 25 to 99 parts by weight of binder and 0.01 to 10 parts by weight of dye. In addition, conventional known sensitizers, either spectral sensitizing compounds or sensitivity-increasing compounds, or both, may be present in the photociter layer.

Are used for producing the recording material of the invention uses insulating binder, so such binders are used preferably that the surface resistance of Photoleiier binding · mitlel-layer is greater than I0 ^'1 ohm per square unit (z. B. per Quadratruß) is. The electrically conductive layer carrier should preferably be an electrically

see resistance of less than 10 'ohm per Square unit, e.g. B. per square foot.

The thickness of the photoconductor-binder layer can be very different. Normally the layer thickness of the photoconductor-binder layer is measured when dry, about 1-200 microns thick. The photoconductor layer preferably has, im Measured dry condition, a strength of about 3 to 50 microns.

In order to produce images, the recording material according to the invention is preferably first used stored in the dark (dark adaptation) and then either negative in the usual known manner or positively charged, for example by means of a corona discharge with a potential of about 6000 to 7000 volts. The charged recording material is then exposed imagewise, through a Original, or reflex exposed, in contact with an original, creating an electrostatic image of the original is obtained. The invisible, latent image obtained is then in the usual way by means of a usual Developing agent, consisting of carrier and toner, developed.

The carrier can, for example, consist of small glass beads or particles consist of a plastic material or an iron powder. The toner can for example from a pigmented, thermoplastic material with a grain size of about 1 to 100 μ exist, which is based on the recording material to be developed can be melted, making the image permanent. on the other hand the developer can also use a pigment or pigmentiPTtes Resin suspended in an insulating liquid, which may contain a resin in Solution may contain. Is the polarity of the charge on the toner particles opposite to the charge on the electrostatic latent image on the recording material, it becomes one corresponding to the original Record received. However, if the polarity of the toner is the same as that of the electrostatic latent Image, a reverse image or a negative of the original is obtained.

When using a recording material according to the invention can in the manner described on even visible images can be generated. However, it is also possible to use either the initially received transferring the latent electrostatic image or the developed image to a second support.

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

Examples 1 to 5

55

These examples illustrate the large increase in the sensitivity wedge of organic photoliter, if these together with the cyanine dyes used according to the invention !! be used. Of the Increase in sensitivity is based on the spectral (10 sensitivity wedge, which the photoconductor by addition of the dyes used in the invention is imparted. The examples also show that the sensitivity maxima or maximum sensitization peaks ("Abs. max.") in most cases at 6s occurs about 350 to 625 nanometers.

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

The solutions were applied to an aluminum layer carrier consisting of a paper carrier with an aluminum foil laminated thereon at 25 ° C. and dried on the carrier. All measures were carried out in a dark room Potential of about 600 volts charged and exposed through a transparent template with a pattern of different optical density by a tungsten lamp of 3000 ^{0 K.}

The resulting electrostatic images were then developed by cascade development, including a developer was used, the finely divided colored, thermoplastic, electrostatically responsive Toner particles on Gl. contained beads. This developer was applied to the surface of the recording materials applied.

Apart from this development method, development methods can be used with equal success as described, for example, in the following U.S. Patents 2,786,439; 27 86 440; 27 86 441; 28 11 465; 28 74 063; 29 84 163; 30 40 704; 31 17 884; Re 25.779; 22 97 691 and 25 51 582 as well as in the magazine "RCA Review". Volume 15 (1954), pages 469 484.

In the case of the cascade development, as can be seen from Table I below, an image was formed in each case generated.

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 recording materials were charged positively or negatively, specifically with a corona discharge, until the surface potential, as measured by means of an electrometer sample, had reached a potential of 600 volts. The recording materials were then exposed to a tungsten light source of 3000 K with 215 lux. The exposure was carried out through a graduated gray wedge. The exposure resulted in a reduction in the surface potential of the recording materials under each step of the gray wedge from the original potential Vo to a lower potential K, the exact value of which depends on the amount of light irradiated in meter-candle seconds. The results of the measurements were plotted in a diagram in which the surface potential V for each step was plotted against the logarithm of the exposure. The actual sensitivity of each recording material is expressed in the reciprocal value of the exposure which is required to reduce the surface potential by H) OVoIt. As a result, the sensitivities reported in Table I below are the numerical values of K) ⁴ divided by the exposure in Metcr-Candle-Sckundcn. which is required to reduce the 600 volt charge by 100 volts.

The values obtained are shown in Table 1 below compiled:

709 527/331

Table I.

example Color image Sensing shoulder negative Emplind- No. material create opportunities loaded lich wedge No. supply Upper positive area (Section. loaded 7th Max.) Upper area (nm) Ver without Yes 8th 400 _. equal 760 example 630 1 I. Yes 220 360 520 2 II Yes 400 360 520 3 III Yes 810 490 4th IV Yes 220 530 5 V Yes 500 540

The values compiled in Table I show that in the case of the comparative example with photoconductor, but without dye, only sensitivities of 8 and 7 in the case of positive and negative, respectively Charged surfaces can be achieved, whereas when using the inventively usable Dyes considerably increased shoulder sensitivities can be achieved. A particularly high sensitivity is achieved, for example, in the case of Example 3 with dye III, in which case shoulder sensitivities of 810 and 630 for the positively and negatively charged surfaces, respectively. The maximum sensitivity is 490 nanometers. From these results it can be seen that at Use of dye no. III increases the sensitivity compared to the comparison material a factor of 100 in the case of the positively charged surface and by a factor of 90 in the case of the negatively charged surface Surface is achieved.

The extension of the absolute sensitivity into the range of approximately is also of great importance 540 nanometers, as can be seen from Example 5. Even in the case of Example 4 with the dye IV a considerable increase in sensitivity by factors of 25 and 55, respectively, compared to the comparison material achieved.

Correspondingly favorable results were obtained when instead of those listed in the table Dyes the dyes VI to XII or the dyes listed in Table A were used Correspondingly favorable results were also obtained when, for example, the used Photoconductor, namely 4,4'-bis (diethylamino) -2,2'-dimethyltriphenylmethun, by another known photoconductor, e.g. 0.15 g triphenylamine in in which case the dyes in the form of the p-toluene sulphonate salts were used, or if 1,3,4-triphenyl-2-pyrazoline or 2,3,4,5-tetraphynylpyrrole were used as photoconductors or ^ '- bis-diethylaminobenzophenone was used.

The results obtained clearly show how effective those used according to the invention are Dyes are capable of spectrally sensitizing a wide variety of organic photoconductors. the Dyes used according to the invention are not themselves photoconductive.

Example 6 (comparative example)

This example shows that the results that can be achieved according to the invention cannot be compared with previously known, can achieve spectral sensitizing dyes. The one described in Examples 1-5 The procedure was repeated except that the sensitizing dyes in this time were those in the following The dyes listed in Table C were used:

Table C.

35

40

45 dye name

Pinacyanol

Cryptocyanine

Anhydro-3-ethyl-9-methyl-3 '- (3-sulfo-

butyl) thiacarbocyanine hydroxide

S ^ '- diethyl ^ -methylthiacarbocyanine-

bromide

3-carboxymethyl-5 - [(3-methyl-2-thia2: ol-

idinylidene) -I-methylethylidene] rhodanine

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

3 '- (3-sulfobutyl) thiacarbocyanine hydroxide
l'-ethyl-3-methylthia-2'-cyanine chloride
1,1'-diethyl-2,2'-cyanine chloride

Claims (1)

Palent claims: 1. Electrophotographic recording material composed of an electrically conductive layer support S and having at least one photoconductive layer an organic photoconductor that spectrally sensitizes the photoconductor: nde: n cyanine dye and optionally a binder, which is indicated by the fact that it is a cyanine m dye of the formula