DE3202552C2 - Electrophotographic recording material and its use - Google Patents

Abstract

Electrophotographic recording material with an electrically conductive layer support and applied thereon first and second photoconductive layers with different sensitivity ranges, the first photoconductive layer being multilayered and a charge-transporting layer, which consists essentially of an electron donor, and a charge-carrier-generating layer, which essentially consists of a charge-generating substance, comprised in order from the support, the electron donor for the charge-transporting layer having an electron energy of 1.75 eV or less.

Description

can be calculated according to the following formula by adding equimolar amounts of 2,4,7-trol-9-fluorenone and the electron donor Dissolve in a suitable solvent such as doxan or tetrahydrofuran and the peak wavelength of the absorption spectrum of the resulting solution measures:

e (eV) = Λ · el λ

Here ε is the excitation energy, h is the Planck constant, c is the speed of light and λ is the wavelength.

In the drawing shows

ii Flg. 1 and 2 are views of the structure of various embodiments of the recording material according to the invention

Flg. 3 and 5 show an example of an electrographic method in which the recording material is applicable,

Flg. 4 and 6 are diagrams showing the change in the surface potential of the recording material in the electrophotographic process of Flg. 3 and 5 respectively show.

The drawing shows an electrically conductive layer carrier 1, a first photoconductive layer 2 made up of a charge-transporting layer 21 and a charge-carrier-generating layer 22, an optionally present stromreguHerep.de Zvlschenschleh '. 3. R ^'ne single second layer 4. phoiolellfähigc a multilayer photoleltfählge second layer 4' generating charge carrier of one layer 41 and an M ladungstransportlerenden layer 42 as well as an original 5

Conventional recording materials whose first photoconductive layer consists of a selenium or a Selenium alloy monolayer, have poor flexibility and heat resistance. Different Investigations into the Schtchtaufbau and Materlallen have now shown that these shortcomings can be fixed and a material with the above requirements is obtained by clicking on an electrically conductive substrate; a first photoconductive layer consisting of a charge transporting end Layer and a charge carrier-generating layer in the order mentioned and applies a specific Electron donor used as the main component of the charge transport layer. This first photographic event Layer exhibits excellent electrophotographic properties when positively charged but not noticeably charged with - -gative charging. The reason for that when the negative charge no significant charge took place. It can be seen that the opposite of the negative surface charge positive charges at this tent point from the electrically conductive racket into the charge transporter end Layer of the first photo-capable layer are injected by the action of the electric Field within this layer migrate to the surface and there neutralize the negative surface charge. However, if the excitation energy ε of the electron donor is more than 1.75 eV, the injection of prevents positive charges from the electrode before the first negative charge and a dlchromatic Full separation made impossible.

Suitable materials for the electrically conductive layer support are, for. B. Plates made of metals with surfaces that are difficult to oxidize, such as Al. Cu, brass, stainless steel, Pd, Ag or Au, in particular plates made of metals with a high work function, such as Pd, Ag or Au; Plates made of metal compounds with low electrical resistance, such as SnO ₂ , In ₂ O ₃ , CuJ or CrO ₂ , plastic rolls or papers that are bonded to the aforementioned metals or metal compounds, for. B. have been coated by vacuum evaporation, sputtering or ion plating.

Suitable as electron donors for the charge transport layer 21 of the first photoconductive layer z. B hydrazones of the following formulas I and II and styryl compounds of the formula III.

(D

(II)

O V-N-N = CH-C O> -N

<O V-CH = CH- ^ C O V-N (! H)

Here, R _t denote methyl, ethyl, 2-hydroxyethyl or 2-chloroethyl groups and R ₃ and R ₁ denote methyl, ethyl, benzyl or phenyl groups.

These materials can optionally be used together with a binder. Suitable Binders are e.g. B. polyethylene, polystyrene, polybutadiene, styrene-butadlene copolymers, and polymers Copolymers of acrylic or methacrylic acid esters ^ polyesters, polyamides, polycarbonates, epoxy resins, urethane resins, Silicone resins, alkyd resins, celluloses, poly-N-vinylcarbazole and its derivatives (e.g. those with halogen atoms, such as chlorine or bromine, and substituents such as methyl or amino, on the carbazole structure), Polyvinylpyicn, Polyvinyl anthracene, pyrene-formaldehyde polycondensates and their derivatives (e.g. those with halogen atoms, such as bromine, or substituents such as nitro, on the pyrene skeleton), poly-y-carbazole-ethyl-L-glutamate, styrene resins, chlorinated polyethylene, acetal resins or melamine resins. The amount of binder is preferably 30 in up to 60 percent by weight, based on the electron donor. The binder can also be used together with plasticizers be used; conventional plasticizers, such as those usually used for synthetic resins, are suitable for this purpose be used. The amount of plasticizer is preferably 30% by weight or less based on the binder

The charge transporting layer 21 of the first photoconductive layer is formed by conventional Solution sizing made. The charge transporting layer 21 preferably has a thickness of 10 to 50 um. Usable solvents are e.g. B. toluene, tetrahydrofuran, 1,2-chloroethane, methylene chloride, Benzene and methanol j

On the other hand, the charge carrier-generating layer 22 of the first photoconductive layer made of material |

all that are classified into the following catfish according to the nature of the chromatic light 20 |

will. Ä

a) Sensitive to light in the red range and essentially transparent to light in the blue range: Disazoplgmente:

ζ. B CI pigment blue 25 (CI 21 180; Diana blue) «

Phthalocyanine components:

z. B CI pigment blue 16 (CI 74 100) and / i-copper phthalocyanine; I.

b) sensitive to light in the blue area and essentially transparent to light in the red area: | inorganic substances: | z. B. Selenium. Selenium-tellurium alloys and cadmium sulfide; Dlsazo pigments:

z. B. Cl-Plementrot 41 (CI 21,200);

Xanthene plants:

z. B. CI Acld-Red 52 (CI 45 100);

Indigo pigments: & f |

z. B. CI Vat Braun 5 (CI 73 410); |

Peryien Pigments: -

z. B. Algol scarlet fever G (CI 60 750) and indanthrene scarlet fever R (CI 71 140).

In the case of a) and b), the disazo pigment is particularly preferred as the charge carrier-generating substance. JO If necessary, a binder can be used together with these materials, preferably In an amount of 50 percent by weight or less based on the charge carrier generating material. The charge carrier generating layer 22 can, for. B. by vapor deposition, sputtering or solution or Dispersion coatings are produced. The layer preferably has a thickness of 0.1 to 1 μm.

The following are the materials for the second photoconductive layer 4,4 'depending on the type of chromatic light.

1. In the case of the single-layer second photoconductive layer 4:

a) Sensitive to light in the red area and essentially transparent to light in the blue area:

Mixtures of phthalocyanine pigments, e.g. B. metal-free phthalocyanine or copper phthalocyanine, 50 | with the aforesaid binder resins; and mixtures of coconut oil complexes of pyrylium dye

materials, such as pyrillum, thiapyryllum or selenapyryllum salts, and polycarbonates with the next- I

existing electron donors. In the case of the first-mentioned mixtures, the amount of binder is preferably 10 to 70 percent by weight, based on the phthalocyanine pigment, while in the case of The latter mixtures, based on the amount of electron donor, preferably 10 to 50 percent by weight on the cocrystalline complex. The weight ratio of pyrolytic dye to polycarbonate in the cocrystalline complex is preferably 1: 900 to 1: 500.

Suitable electron donors are e.g. B. Compounds with at least one alkyl group, such as methyl, alkoxy, amino, imino and / or imido groups on the main or side chain and compounds that \

wear to the main or side chain polycyclic ^ aromatic radicals such as anthracene, pyrene, phenanthrene or coronene w ί, or nitrogen-containing cyclic groups, such as indole. Carbazole, isooxazole, f

Thlazole, Imidazo !, Pyrazole, Oxadiazole, Thiadiazole and Triazole. Specific examples are low molecular weight i

Electron donors, such as hexamethylenediamine, N- (4-aminobutyl) -cadaverine, asam.-didodecylhydrazine,!

p-toluldine, 4-amino-o-xylene, N.N'-diphenyl-1-4-diaminoethane. o-, m- or p-ditolylamine, triphenyl- j

amine, diphenylmethane, triphenylmethane, durol, 2-bromo-3,7-dimethylnaphthalene, 2,3,5-trimethyinaph- «5 thalin, N'-O-bromophenyD-N-iß-naphthyD-urea, M-methyl-N- (α-naphthyl) -urea. N, N'-DIethyl-N- (a-naphthyI) urea, 2,6-dimethylanthracene, anthracene, 2-phenylanthracene, 9,10-diphenylanthracene, 9,9'-BianthranyI, 2-dimethylaminoanthracene, phenanthrene, 9-aminophenanthrene, 3,6-dimethyl

phenanthrene, SJ-Dlbromo ^ -phenylindole, 2,3-Dlmethyllndolln, 3-indolylmethylamln, carbazole, 2-methylcarbazole, N-Ethylcarbazole, 9-Phenylcarbazole, 1,1-Dicarbazole, 3- (p-Methoxyphenyl) -oxazolldln, 3,4,5-Trlmethylisooxazole, 2-Anlllno-4,5-diphenylthlazole, 2,4,5-TrlnltrophenyIlmldazole, 4-Amlno-3,5-dlmethyl-1-phenylpyrazole, 2,5-D! Phenyl-1,3,4-oxadlazole, 1,3,5-tri-phenyl-1,2,4-trlazole, l-Amino-5-phenyltetrazole and Bls-dlethylaminophenyl-l ^ ö-oxadlazole. Specific examples of high molecular weight Electron donors are poly-N-vinylcarbazole and its derivatives (e.g. those with halogen atoms, such as ChIr "or bromine, or substituents such as methyl or amino on the carbazoy skeleton), polyvinylpyrene, Polyi-sTiylanthracen, pyrene-formaldehyde-polycondensates and their derivatives (e.g. those with halogen atoms, such as bromine, or substituents such as nitro, on the pyrene framework).

b) Sensitive to light in the blue range and essentially transparent to light in the blue complementary moose (red area):

Mixtures of inorganic pigments, such as cadmium sulfide and zinc oxide, with the above-mentioned oils.

The single layer second photoconductive layer can be made using conventional solutions and Dlsperslonsbeschlchtung.

2. In the case of the multilayer, second photoconductive layer 4 ':
2-1. Charge carrier generating layer 41

This layer corresponds to the charge carrier generating layer for the first photoconductive layer.
2-2. Charge transport layer 42

This layer corresponds to the charge transport layer for the first photoconductive layer with the Exception that, instead of the specific electron donor, the electron donor for the first photocellable Layer is used.

Preferably, the single-layer second photoconductive layer 4 has a thickness of 10 to 30 µm Charge carrier-generating layer 41 for the multi-layered second photoleltfahlge layer 4 'has a thickness from 0.1 to 1 μm and the charge-transporting layer 42 has a thickness of 10 to 30 μm.

If necessary, there is a photoconductive seal between the first photoconductive layer 2 and the second Layer 4, 4 'a current-regulating intermediate layer 3 is provided to allow the passage of electrical To prevent current between these layers and possibly to increase the optical filter effect. the Current-regulating intermediate layer is made of an organic material, e.g. B. one of the named Binding resins, or an inorganic material such as silicon oxide or magnesium fluoride. The thickness of this layer is preferably 0.3 to 3 µm. You can z. B. according to one of the following Process are produced:

1) Organic materials soluble in a solvent, such as polyester, urethane or phenolic resins, are dissolved in a solvent to a concentration of 5 to 20 percent by weight. The received The solution is applied, heated and dried using a squeegee or by dipping. Possibly the polymerization or curing can be promoted by UV irradiation.

2) In the case of a polymerisation of a material insoluble in organic solvents, such as Polyethylene or fluororesins, produced intermediate layer can this with an adhesive, z. B. a solvent-soluble resin, to be laminated on the first photoconductive layer and the second A photoconductive layer can be formed on this film.

3) In the case of polyxylene, which can be polymerized into a film. can do this directly on the first photo Layer are polymerized.

4) In the case of inorganic materlallen or some organic materials, e.g. B. fluororesins, can the intermediate layer can be produced by vacuum vapor deposition or sputtering.

5) If the intermediate layer is to be given a filtering effect, this can be done by dispersing the said pigment for the charge carrier-generating layer of the first or second photoleltfählgen Layer In the material for the intermediate layer or by vapor deposition or sputtering of the Pigments are made.

In the following with reference to Flg. 3 to 6 the process according to the invention for the production of two-color copies explained in more detail using an exemplary embodiment, in which red light as chromatic Light is used.

Procedure I (Flg. 3 and 4)

In the case of the recording material used in this process, the first photoconductive layer must be 2 at least be sensitive to red light, but can also be panchromatic if the second photoleltfählge Layer 4,4 'has the property of essentially absorbing or being sensitive to blue light. The recording material is subjected to a first charge in the dark, only the second photoconductive charge Layer 4,4 'to charge (Flg.31), whereupon it is subjected to a second charge, in which the The polarity of the surface potential becomes positive (Fig. 3 II). The recording material is then exposed imagewise through an original 5 with black and red areas, the potential of the surface of the Recording material corresponding to the black area of the original remains positive while the potential the area which is in the same way as the red area of the original becomes negative and the potential of the area which

^{(Is corresponds to} the white area of the original, becomes practically zero (Fig. 3 HI). Although not shown, the obtained positive black latent image and the negative red latent image are successively developed with a negatively charged toner and a positively charged red toner, respectively , then transferred to an image receiving material such as paper and fixed to a red-black copy. Fig. 4 shows the change in the surface potential

tials in each of these stages.

Procedure II (Flg. 5 and 6)

In the recording material used in this method, the first photoconductive layer 2 at least be sensitive to blue light, but can also be panchromatic if the second is photoconductive Layer 4, 4 'has the properties of absorbing red light. On the other hand, the second must be photoconductive Layer 4, 4 'be sensitive at least to red light and allow light of the area to pass through for which the first photoconductive layer 2 is sensitive.

The recording material is subjected to a first charge in the dark in order to charge only the second photoconductive layer 4, 4 '(Fig. 5I), and then subjected to a positive or alternating current charge with a lower electrical potential than the first charge in order to lower the potential somewhat , but to maintain its polarity (Flg. 5 II). The recording material thus treated is then exposed as in Fig. 3 Ul bi'dmäßlg, wherein the potential of the fishes of the recording material corresponding to the black area of the original, remains unchanged, while the potential of the area corresponding to the white area of the original, becomes practically zero and the potential of the area corresponding to the red area of the original becomes positive (Fig. 5 III). The latent image obtained is then developed with a red toner and a black toner as in Fig. 3 except that the toners have reversed polarity. The desired red-black copy is obtained by transferring it. Figure 6 shows the change in surface potential during these stages.

The above electrophotographic procedures were carried out using a red and black Originals explained as an example. However, the procedures are of course not based on such an original limited, but a wide variety of two-tone originals such. B. blue-black, red-blue or green-black, can be used when the spectral properties of the first and second photoconductive are used Layer can be chosen appropriately. Furthermore, the recording material according to the invention is also customary Carlson method can be used. The original does not have to be two-tone either, but can also be panchromatic, z. B. 3-colored or multi-colored. When reproducing 3 or more colored originals using the Carlson process black and white copies are obtained with a clear difference in image density.

Although a drawing material was used above which does not have a current-regulating intermediate layer has, favors such an intermediate layer depending on the nature of the first and second photographic elements Layers sometimes during the injection of positive charges into the second photoconductive layer the first charge and prevents positive charges from escaping to the substrate side during the second charge. If the intermediate layer is also colored and thus has an optical filter effect unfolded, the wavelength distribution and the amount of light reaching the first photoconductive layer can be can be controlled so that a wider range of materials for the first and second photoconductive layers is available.

The following examples illustrate the invention. All parts and percentages are based on weight, unless otherwise stated.

B e i s ρ i e 1 1

An electrically conductive layer support is applied by vacuum vapor deposition of Pd to a thickness of 50 nm the A! -damped side of a 75 μm thick polyester film is produced. In addition, a solution is produced by breaking 1 part of the connection

O> C ₂ H ₅

as an electron donor and 1 part of a polycarbonate resin in tetrahydrofuran to a solids concentration of 20%. The solution is applied to the vapor-deposited Pd layer of the support and for 5 minutes at a time dried about 34 μm thick charge transporting layer for the first photoconductive layer. Besides a solution is prepared by adding 2 parts of the disazo pigment

o> - N C ₂ H ₅ \ ÖS -CH = CH- \ O> \ /

CH ₃

H ₃ C

H ₃ C- <O> -HNOC

CONH

CH ₃

CH

as a charge carrier generating substance and 1 part polyester resin in tetrahydrofuran to a solids concentration of 1.5 ° 6 and 3 minutes grinding in a ball mill. The solution obtained is on the charge-transporting Layer applied and 1 minute at 80 ° C to an approximately 0.2 μm thick charge carrier generating Layer for the first photoconductive layer dried. It will thus be a multi-layered first ~ hc'c! sitfuh! "e layer received

A 10 percent methanol solution of a phenolic resin is then applied and dried for 30 minutes at 50 ° C. to form an approximately 1 μm thick current-regulating intermediate layer. Selenium is vapor-deposited onto this intermediate layer at a substrate temperature of 50 ° C. and a vacuum of 6.5 10 " ⁵ mbar in a thickness of about 0.5 μm in order to form a charge carrier-generating layer for the second photoconductive layer 1 part polyvinyl carbazole and 1 part polycarbonate resin dissolved in dichloroethane. The solution is applied and dried for 60 minutes at 50 ° C. to form an approximately 12 µm thick charge transport layer for the second photoconductive layer. A multilayer second photoconductive layer is thus obtained.

The recording material produced in this way has a first corona charge of -6.5 kV up to a Surface potential of -2200 V and then a second corona charge of +5.5 kV up to a surface potential subject to +730 V. The recording material is then exposed imagewise with a red-black-white original. The resulting latent electrostatic image has a surface potential In the area -35OV corresponding to the red area of the original, in the area of the black Area of the original and the area corresponding to the white area (background) of the original corresponding range practically 0 V. The latent electrostatic image is then successively with a Developed red toner and a black toner and transferred to plain paper, creating a sharp two-tone Image receives. The recording material is bent into a cylindrical shape and shows no change up to a bending radius of 10 mm. Keeping it at 70 ° C for an hour does not cause any impairment either of the recording material.

Vergielchsbelsplel 1

A recording material is produced according to Example I, but a single-layer first is produced photoconductive layer by vapor deposition of a Se-Te alloy containing 10% Te to a thickness of eiwa 70 μιπ at a subsirate temperature of 69 ° C and a vacuum of 6.65 χ 10 * mbar. This recording material enables a two-color copy of similar quality to that of Example 1 to be made However, if you bend up to a 3-bend radius of 50 mm. so the first photoconductive layer breaks and peels If this recording material is kept at 70 "C. for 30 minutes, a copy of only less is produced Bllddlchtc

Example 2

An electrically conductive layer support is applied by vacuum vapor deposition of Pd In to a thickness of 100 nm the ΑΙ-vapor-coated side of a 75 μm thick polyester film is produced. In addition, I becomes part of the connection

C ₂ H ₅

as an electron donor and 1 part of the polycarbonate resin of Example 1 in tetrahydrofuran to a solids concentration solved by 20%. The solution is applied to the vapor-deposited Pd layer and closed for 5 minutes an approximately 20 µm charge transport layer for the first photoconductive layer. on the other hand 2 parts of acrylic components of the formula

H ₃ CN

> -

- <O

N-CH ₃

as a charge carrier generating substance and the polyester resin of Example 1 in tetrahydrofuran to a solids concentration of 2% and ground in a ball mill for 5 minutes. The solution is then applied to the charge-transporting layer and dried for 1 minute to form an approximately 0.3 μm thick charge-carrier-generating layer. A multilayered first photoconductive layer is thus obtained.

Then a 7 percent hot methanol solution of a polyamide resin is applied and 30 minutes dried at 50 ° C. to form an approximately 1 μm thick current-regulating intermediate layer. A solution made up of 2 parts ^ p-Dimethylaminophenyl ^ o-diphenylthiapyrylium perchlorate, 42 parts of triphenylmethane, 56 parts of the polycarbonate resin from Example 1 and 1000 parts of methylene chloride is then applied to this intermediate layer and 60 minutes at 60 ° C. to form an approximately 30 μm thick, single-layer second photoconductive layer (cocrystalline complex system) dried.

If this recording material is used in the electrophotographic process of Example 1, then you get a very good red-black copy. The recording material also has similarly good flexibility and Heat resistance as in example 1.

Comparative example 2

A recording material is produced according to Example 2, but a single-layer, first polymeric layer is produced by vapor deposition of a 6% Te-containing Se-Te alloy which contains 60 ppm Cl, in a thickness of about 40 μm at a substrate temperature of 80 ° C. and a vacuum of 6.65 χ 10 ~ ⁵ mbar. Although this recording material gives a two-tone copy that is as good as in Example 2, its flexibility is similar to that in Comparative Example 1. After the one-hour heat resistance test at 70 ° C., a two-tone copy is also obtained that has a very poor image density, especially in the red area having. Therefore, the first photoconductive layer cannot be used in practice when the second photoconductive layer must be dried at a high temperature.

Example 3
A recording material is produced according to Example 1, except that the compound is used

CH ₂

CH _;

as an electrolyte donor for the charge-transporting layer of the first photoconductive layer. The recording material is sequentially the first corona charge, the second corona charge and the imagewise Subjected to the exposure of Example 1 to obtain an electrostatic latent image whose surface potential in the area corresponding to the red area of the original -370 V, in the area corresponding to the black Area of the original +660 V and In that of the white area of the original corresponding range is practically 0 V. The recording material shows similarly good flexibility and Heat resistance as in Example I.

For this purpose 2 sheets of drawings

Claims (12)

Patent claims: 1. Electrophotographic recording material with an electrically conductive layer support and a first and second photoconductive layers applied thereon, which are for different wavelength ranges are sensitive, characterized in that the first photoconductive layer is multilayered is and, in the order of the substrate, a charge-transporting layer which is im consists essentially of an electron donor, and a charge carrier-generating layer, which in the consists essentially of a charge carrier-generating substance, the electron torch for the charge transporting layer has an excitation energy of 1.75 eV or less. 2. Recording material according to claim 1, characterized in that in the charge-transporting Layer of the first photoconductive layer, electron donor used a compound of the general Formula 1, II or HI is: \ / I \ / R ₂ (I) Ri 20th R ₁ R ₂ f> (! 1) / ÖV-N —N = CH- / Ö \ -N R ₃ R ₂
-CH = CH- <O> -N (III) where R is a methyl, ethyl, 2-hydroxyethyl or 2-chloroethyl group and R ₂ and R are methyl, ethyl. Mean benzyl or phenyl groups. -to 3. Recording material according to claim 1 or 2, characterized in that the! Jdungstransportle- The layer of the first conductive layer contains a binder in an amount of 30 to 60% by weight., based on the electron donor. 4. Recording material according to one of claims 1 to 3, characterized in that the in the Charge carrier-generating layer of the first photoconductive layer used charge carrier-generating • 15 substance a disazo. Is phthalocyanine, xanthene, indigo or perylene fragment or cadmium sulfide. 5. Recording material according to one of claims 1 to 4, characterized in that the charge carrier-generating Layer of the first photoconductive layer a binder in an amount of 50% Weight percent or less based on the charge carrier generating substance. 6. Recording material according to one of claims 1 to 5, characterized in that the second photoconductive layer is single-layer. 7. Recording material according to claim 6, characterized in that the second photoconductive element Layer of a mixture of a binder with a phthalocyanine component; a mixture of one coconut complex of a Pyryilum dye and a polycarbonate with an electron donor, which is different from the electron donor of the first photoconductive layer; or a mixture consists of a binder with cadmium sulfide or zinc oxide. 8 recording material according to one of claims 1 to 5, characterized in that the second photoconductive layer is multilayered and in order from the first photoconductive layer a charge carrier generating layer consisting essentially of a charge carrier generating substance and comprises a charge transport layer consisting essentially of an electron donor * "which is different from the electron donor of the first photoconductive layer. 9. Recording material according to claim 8, characterized in that in the charge carrier-generating Layer of the second photoconductive layer used a charge carrier generating substance Disazo, phthalocyanine, xanthene, indigo or perylene fragment, selenium, a selenium-tellurium alloy or Cadmium sulfide is. <> 5 10. Recording material according to claim 8 or 9, characterized in that the charge carrier forming layer of the second photoconductive layer contains a binder in an amount of 50% by weight or less, based on the charge carrier generating substance. 11. Recording material according to one of claims 8 to 10, characterized in that the charge transporting layer of the second photole'tfähigen layer comprises a binder in an amount of 30 to 60 weight percent, based au ^r the electron donor contains. 12. Use of the recording material according to one of claims 1 to 11 for the production of two-tone copies. The invention relates to an electrophotographic recording material according to the preamble of the claim 1. and its use according to claim 12. It is already known an electrophotographic recording material for the two-color process, the a first and a second photoconductive layer in succession on an electrically conductive layer support has different sensitivity ranges. When copied, this material becomes either a) a subjected to a first charge and then a second charge with opposite polarity or b) the recording material is subjected to a first charge, simultaneously or subsequently evenly is exposed to light of a wavelength capable of making one of the photoconductive layers conductive to make, and then performs a second charge so that each of the photoconductive layers has a Has charge of opposite polarity. The recording material thus treated then becomes imagewise exposed through an original with black and colored (usually red) areas, being latent electrostatic images are created whose surface potential corresponds to the black area of the original has opposite polarity as the surface potential in the part that corresponds to the colored area of the original. The latent images are finally shown one after the other with a black and a colored toner developed and transferred. The recording material used in this process is subject to the requirement that at least one of the photoconductive layers, even if it is both positively and negatively charged, overlies exhibits or possesses electrophotographic properties when either positive or is negatively charged, but is not significantly charged with the other polarity and is therefore hardly charged shows electrophotographic properties. A typical recording material of this type (DE-OS 30 14 002) comprises a single layer first photoconductive layer of selenium or a selenium alloy, e.g. 3. Se-Te, on. However, this recording material has the disadvantage that it is not very flexible and therefore only limited is applicable, ζ B. can only be used with difficulty in sheet or tape form. Another disadvantage is that although generally an intermediate layer or second photoconductive layer through Solution coating or vacuum evaporation can be applied to the first photoconductive layer, however, this can be destroyed due to the heat generated in the drying process Case of the Lackler process or due to the heat developed by the vapor deposition source Vapor deposition. From DE-OS 30 18 S ⁷ 'an electrophotographic recording material is known which has a photoconductive double layer on an electrically conductive layer support which, in the order from the layer support, comprises a charge-generating layer and a charge-transporting layer applied thereon . However, this recording material is not suitable for the production of both monochrome and two-color copies. The object of the invention is therefore to provide an electrophotographic recording material of the type mentioned at the beginning To provide with improved flexibility and heat resistance chain that is not a limitation with regard to the type of application and no / no risk of destruction of the first photoconductive layer. The subject of the invention is a clektrophotographic recording material with an electrically conductive 4 * the support and a first and / second photoconductive layer applied thereon, which layer is used for different Wavelength ranges are sensitive, which is characterized in that the first photolcitfählge Layer is multilayered and in the order of the layer support a charge-transporting one Layer which consists of an Ir / essentially electron donor and a charge carrier generating one Layer, which consists essentially of a charge carrier-generating substance, the electron 5n ncndom-r for the charge transporting layer has an excitation energy of 1.75 eV or less. In the recording material according to the invention, the first and second photoconductive layers must be meet the following basic conditions for the two-color copies srfaiiron. The first photoconductive layer muli to be sensitive to chromatic light passing through the second photoconductive layer and also have the characteristic that it is hardly charged with negative charging and with positive ^ Charging shows excellent electrophotographic properties On the other hand, the second must be photoconductive Layer to be sensitive to part of the chromatic light and within the visible range allow the other part of the chromatic light to pass through, as well as excellent negative charging Have electrophotographic properties If these conditions are met, the second photovoltaic layer be single-layer or multilayer, d. H. one after the other a charge carrier eye 6n Layer and a charge transport layer on the first photoconductive layer or a strermregullercnden Include intermediate layer. In order to achieve this, the first photoconductive layer must have a charge transport function from the support Layer and a charge carrier-generating layer commit and the charge-transporting The layer must contain the specific electron donor mentioned as its main component. This electron donor has a recovery energy of 1.75 eV or less in light absorption measured as a batch Transfer complex obtained by mixing equimolar amounts of the electron donor and 2,4,7-TrlnItro-9-lluorenone is obtained. 2,4,7-Trinltro-9-fluorenon serves here as electron acceptor. The excitation energy