Multilayered electrophotographic recording medium

Claim 2

An electrophotographic recording medium which consists essentially of an electrically conductive base, a first layer containing charge carrier-producing dyes, and a second layer which is substantially transparent to actinic light and is composed of an insulating organic material containing at least one compound which is charge carrier-transporting when exposed to light, wherein the charge carrier-producing dye is of the formula I ##STR21## where R 1 , R 2 , R 3 and R 4 are each hydrogen, halogen, methyl or methoxy, or one or two of the radicals R 1 , R 2 , R 3 and R 4 are C 1 -C 6 -alkyl, phenyl, phenoxy, phenylthio, nitro, amino N,N-C 1 -C 4 -dialkylamino, a radical of the formula ##STR22## or a radical of the formula --NHCOR 5 , where R 5 is C 1 -C 6 -alkyl or unsubstituted or substituted phenyl, and the remaining radicals R 1 , R 2 , R 3 and R 4 are each hydrogen, X is the radical of a methylene-active compound or a radical of the formula ═N-R 6' , where R 6' , is the radical of an aromatic or heterocyclic amine or hydrazine, and Z is hydrogen, methyl or phenyl.

Claim 3

An electrophotographic recording medium as claimed in claim 1, wherein the charge carrier-producing dye is of the formula II ##STR23## where R 1 , R 2 , R 3 and R 4 are each hydrogen or halogen, or one or two of the radicals R 1 , R 2 , R 3 and R 4 are phenyl, phenoxy, phenylthio or nitro, and the remaining radicals R 1 , R 2 , R 3 and R 4 are each hydrogen, R 6 is cyano, nitro, 4-halophenyl, 4-cyanophenyl, 4-nitrophenyl, C 1 -C 8 -alkoxycarbonyl, phenoxycarbonyl, carbamyl, or N-phenylcarbamyl which is unsubstituted or monosubstituted to trisubstituted by chlorine, bromine, methyl and/or methoxy, or is N-C 1 -C 4 -alkylcarbamyl, or phenyl which is substituted in the 4-position by cyano, nitro or CF 3 , or phenylsulfonyl which is monosubstituted to trisubstituted in the phenyl nucleus by chlorine, bromine and/or C 1 -C 4 -alkyl, or is a radical of the formula ##STR24## where A is --O--, --S-- or N-R, R is hydrogen or C 1 -C 4 -alkyl, and R 7 and R 8 are each hydrogen, halogen, C 1 -C 4 -alkyl or C 1 -C 4 -alkoxy, or R 6 is 1H-naphth-[2,3-d]-imidazolyl, pyridyl, thiazol-4-yl, 2-methylthiazol-4-yl, 2-phenyl-1,3,4-thiadiazol-5-yl, quinolin-2-yl, indol-3-yl or benzthiazol-3-yl.

Claim 4

An electrophotographic recording medium as claimed in claim 2, wherein the charge carrier-producing dye is of the formula II where R 1 , R 2 , R 3 and R 4 are each hydrogen or chlorine, or one or two of the radicals R 1 , R 2 , R 3 and R 4 are phenyl, phenoxy, phenylthio or nitro, and the remaining radicals R 1 , R 2 , R 3 and R 4 are each hydrogen, and R 6 is cyano, methylcarbonyl, phenylcarbonyl, 4-nitrophenyl, 4-cyanophenyl, C 1 -C 6 -alkoxycarbonyl, phenoxycarbonyl, phenylsulfonyl or a radical of the formula ##STR25## where A is --O--, --S-- or N-R, R is hydrogen or C 1 -C 4 -alkyl, and R 7 and R 8 are each hydrogen, halogen, C 1 -C 4 -alkyl or C 1 -C 4 -alkoxy, or R 6 is 1H-naphth-[2,3-d]-imidazolyl, pyridyl, thiazol-4-yl, 2-methylthiazol-4-yl, 2-phenyl-1,3,4-thiadiazol-5-yl, quinolin-2-yl, indol-3-yl or benzthiazol-3-yl.

Claim 5

An electrophotographic recording medium as claimed in claim 1, wherein the charge carrier-producing dye is of the formula III ##STR26## where R 1 , R 2 , R 3 and R 4 are each hydrogen or halogen, or one or two of the radicals R 1 , R 2 , R 3 and R 4 are phenyl, phenoxy, phenylthio or nitro, and the remaining radicals R 1 , R 2 , R 3 and R 4 are each hydrogen, and B is the complement needed to form a pyrazolone, oxazolone, isooxalone, imidazolone, cyclohexanedione, dimedone, pyridone or 4-hydroxycoumarin radical or ##STR27## is a radical of the formula ##STR28##

Claim 6

An electrophotographic recording medium as claimed in claim 1, wherein the charge carrier-producing dye is of the formula IV ##STR29## where R 1 , R 2 , R 3 and R 4 are each hydrogen or halogen, or one or two of the radicals R 1 , R 2 , R 3 and R 4 are phenyl, phenoxy, phenylthio or nitro, and the remaining radicals R 1 , R 2 , R 3 and R 4 are each hydrogen, and R 9 is a radical of the formula ##STR30## where R 10 , R 11 and R 12 may be identical or different and each is halogen, C 1 -C 4 -alkyl or C 1 -C 4 -alkoxy, or R 10 is nitro or cyano and R 11 and R 12 are each hydrogen, halogen, C 1 -C 4 -alkyl or C 1 -C 4 -alkoxy, or R 9 is the radical of a heterocyclic amine.

Claim 7

An electrophotographic recording medium as claimed in claim 1, wherein in the second layer, which is substantially transparent to actinic light, the compound which is charge carrier-transporting when exposed to light is poly-(N-vinylcarbazole).

Claim 8

A process for the production of an electrophotographic recording medium as claimed in claim 1, wherein a first dispersion containing charge carrier-producing dyes is first applied to an electrically conductive base to give a 0.005-5 μm thick dry layer, a conventional barrier layer is then applied, if desired, and thereafter a solution of an insulating organic material, together with a compound which is charge carrier-transporting when exposed to light, is applied to form a second layer which is 2-40 μm thick when dry.