DE2936306C2 - Electrophotographic recording material - Google Patents

Description

40

The invention relates to an electrophotographic recording material according to the preamble of claim 1, which is used for the production of two-tone, e.g. B. black and red. Copies from a multicolored original is enabled by only one exposure.

There are already known electrophotographic recording materials which are based on a conductive Layer support one after the other z. B. a photoconductive selenium layer and a charge transporting layer Layer, e.g. B. made of polyvinyl carbazole. These materials are designed to have a surface potential a single, positive or negative polarity corresponding to that of charging and exposure generated electrostatic latent image. To make two-color copies with these It is therefore usually necessary for recording materials to follow the cycle of charging, exposure and development and repeat transmission. However, simply repeating this cycle does not give one sharp, two-tone image as mixed colors, haze and overlaps occur.

In JP-OS 1 46 832/1976 there is therefore a two-color copying process described, in which a recording material that is on a conductive bi Layer support has successively an insulating layer and a photoconductive layer, a first corona charge subjects the charged material overall to light that enters the sensitive area of the photoconductive layer falls, exposed either simultaneously with or after the first corona charging and then the second corona charge of the material with a polarity opposite to the first charge at the same time as the pictorial. Exposure of the original, which has white, black, and red areas (i.e. the two-color original with red and black image areas) through a red complementary color filter then it is exposed again imagewise through a red filter developed with a red toner, then exposed to panchromatic light and finally carries out a second development another toner. The toner images obtained are printed on an image receiving material, e.g. B. Papers, transferred and fixed. However, this method has the disadvantage that a significant amount of light is required for exposure is required and also two different filters must be used.

In the older, later published DE-OS 29 06 500 is an electrophotographic recording material is described, which is on a conductive Layer support an inner photoconductive layer which is insensitive to light of a first color and sensitive to light of a second color, a transparent insulating layer and an outer photoconductive one Has layer which is sensitive to light of the first color and to light of the second Color is insensitive.

The object of the invention is to provide a similarly constructed electrophotographic recording material with a to provide a first photoconductive layer, an intermediate layer and a second photoconductive layer, wherein the intermediate layer provides an injection of free charges between the first and second prevents photoconductive layer and thereby enables the production of clear, sharp two-color copies.

This object is f after the E ^"; invention with an electrophotographic recording material according to the main claim solved.

The recording material according to the invention is characterized in that

1. each image of a multicolor original according to the usual Carlson process reproduced in mutually graduated degrees of density with a monochrome toner can be and

2. from a two-color original using the two-fold copying process described below a two-tone image can be produced.

The feature I can only through the properties of the first and second described in the main claim photoconductive layers of the recording material according to the invention are realized, namely the absorptivity for a specific wavelength and the chargeability. Since in the invention Recording material the upper, d. H. second photoconductive layer absorbs a light region B, achieved this lichi B the lower, d. H. the first photoconductive Layer not or only to a very small extent, even if you touch the surface of the recording material irradiated with a light comprising light A and light B. Therefore, the first needs photoconductive Layer not to be limited to sensitivity to light A alone, but it can both be sensitive to light A as well as light B.

The feature 2 is realized by the first and / or second photoconductive layer positive Gives negative chargeability or by adding the first photoconductive layer in addition to that in the main claim basic properties mentioned a commutation ability with respect to the conductive layer carrier confers

"Positive-negative chargeability" is understood to mean the property of a layer, both positive and also to be able to be charged negatively and also to enable a fall in light. Under »Commutation« the property is understood to be only able to be charged either positively or negatively and further to allow light decay in charging polarity.

In the drawing, F i g. 1 shows a greatly enlarged section through a recording material according to the invention, where 1 is the recording material, 11 is the conductive support, 12 is the first photo-conductive Layer, 13 the intermediate layer and 14 the second photoconductive layer. Figs. 2,4 and 6 illustrate the electrophotographic process using a recording material according to the invention. 3, 5 and 7 illustrate the properties of the recording material according to the invention.

The in Fig. 1 shown recording material comprises a conductive layer support 11 on which one first photoconductive layer 12 having a sensitivity at least to light A, an intermediate layer 13 and a second photoconductive layer 14 are applied, which transmits the light A and opposite Light B is sensitive.

The first and second photoconductive layers 12 and 14, respectively, have the basic properties described above and can be made using compositions consisting essentially of the following combinations 1 or 2 are made positive-negative-chargeable:

Combination 1

Combination of a substance that generates a charge when light A or B is absorbed (positive or negative conductive carrier) [e.g. B.

1. coloring pigment,

2. dye,

3. Combination of donor and acceptor, which enables the absorption of a Ch & rge transfer complex in one Color range can effect, or

4. Combination of a non-coloring pigment with a dye] with a substance that either sport a positive or negative charge can [e.g. B.

(a) a P photoconductor or donor as a positive charge transport substance or

(b) an N-photoconductor or acceptor as a negative charge-transporting substance].

The above combination must meet the following conditions:

i) Effective charge generation during the absorption of light A or B, d. H. high quantum yield;

ii) effective injection of positive or negative Charges in the charge-transporting substance and

iii) high charge mobility of the charge-transporting substance.

Each of the substances mentioned below can satisfy the above conditions.

Combination 2

Combination of two types of charge-transporting substances that are both positive and negative Can transport loads, e.g. B. Combinations of N-photoconductors with P-photoconductors or donor-acceptor combinations, in which one of the components is present in excess. There is a high for excess donor or P-photoconductor Hole mobility, for excess acceptor or N-photoconductor a high electron mobility is required. The substances named below meet these requirements.

Examples of coloring pigments, non-coloring pigments, dyes, donors, which can be used according to the invention Acceptors, P-photoconductors and N-Ph.; Toconductors are:

Coloring pigments (group A)

Arno, phes Se and those that use spectral sensitizers such as contains As or Te; Cadmium sulfide as well as doped with Cu; Cadmium selenide; Zinc sulftd; trigonales Selenium; Azo pigments such as Sudan Red (CI Solvent Orange 7). Diana blue (Cl 21 180); Quinonpsgmente, like Algol yellow (CI Vat Yellow 2), pyrenquinone or lndanthrene brilliant violet RRP (CI Vat Violet I); Indigo pigments such as indigo (CI 7300) and thioindigo (CI 73,300); Bis-benzimidazoi pigments, such as Indo Fast Orange toner (CI Vat Orange 3); Phthalocyanine pigments such as Cu phthalocyanine; Quinacridone pigments; and perylene pigments.

Non-coloring pigments (group A ') T'tandioxid and zinc oxide.

Dyes (group B)

Diphenylmethane dyes, such as Oramin (Cl 41,000 B); Tripnenylmethane dyes. such as tetrabromophenol blue, crystal violet (CI 42 555) or malachite green (Cl 42,000); Xanthene dyes such as fluorescein (CI 45 350); Rose bengal (Cl 45 435) or rhodamine B (CI 45 170); Acridine dyes such as acridine orange (CI 46 005) or acridine yellow (CI B & sic Yellow 4); Azine dyes such as Phenosisffranin or ethylene violet (Cl 42 535); Thiazine dyes, such as phenothiazine or methylene blue (Cl 5 ^ 015); Pyrylium salts such as 1,3,5-triphenylpyrylium perchloral; Selenapyrylium salts such as 4- (4-dimethylarrinophenyl) -2-phenylbenzo [b] selena-pyrylium perchlorate and thiapyrylium salts such as 1,3,5-triphenylthiapyrylium perchlorate.

Acceptors (group C)

Carboxylic acid anhydrides; Compounds with electron acceptor structure, z. B. o- or p-quinoid structure; aliphatic, cyclic compounds with electron acceptor substituents. such as nitro, nitroso and cyano groups; aliphatic compounds; heterocyclic Links; specific examples are maleic anhydride. Phthalic anhydride.

Tetrachlorophthalic anhydride. Tetrabromophthalic anhydride, naphthalic anhydride, pyromellitic anhydride, chloro-p-benzoquinone,
2,5- and 2,6-dichlorobenzoquinone. Se-dichloronapthoquinone, o-chloranil, o-bromanil, p-chloranil, p-bromanil, p-) odanil. Tetracyanoquinodimethane, 5,6-quinolinedione, coumarin-2,2-dione, oxyindirubin, oxyindigo, 1,2-dinitroethane, 2-dinitropropane, 2-nitro-2-nitrosopropane, iminodiacetonitrile, succinic acid nitrile, tetracyanoethylene, 1,1,3, 3-tetracyano propylene,
o-, m- or p-dinitrobenzene. 1,2,3-trinitrobenzene. 1,2,4-trinitrobenzene, 1,3,5-trinitrobenzene, dinitrodibenzil, 2,4-dinitroacetophenone. 1,4-dinitrotoluene, 1,3,5-trinitrobenzophenone, 1.23-trinitroanisole, ", ^ - dinitronaphthalene, 1 / 1S-Tptranilronanhthalin.
3,4,5-trinitro-1,2-dimethylbenzene, 3-nitroso-2-nitrotoluene, 2-nitroso-3,5-dinitrotoluene, o-, m- or p-nitronitrosobenzene, phthalonitrile, terephthalonitrile, isophthalonitrile, benzoyl cyanide, bromobenzyl cyanide. Quinoline cyanide. o-xylylene cyanide, o-, m- or p-nitrobenzil cyanide. 3,5-dinitropyridine, 3-nitro-1-pyridine. 3,4-dicyanopyridine, Λ -, ^ - or ^ -pyridine cyanide, 4,6-dinitroquinone. 4-nitroxanthone, 9,10-dinitroanthracene, 1-nitroanthracene. 2-nitrophenanthrenequinone, 2,5-dinitrofluorenone, 2,6-dinitrofluorenone, 3,6-dinitrofluorenone, 2,7-dinitrofluorenone, 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone,
3,6-dinitrofluorenone-mandelic acid nitrile, 3-nitrofluorenone-mandelic acid nitrile and tetracyanopyrene.

Low molecular donors (group D)

Compounds with at least one alkyl group, such as methyl, or an alkoxy, amino, imino or imido group in the main or side chain; polycyclic aromatic compounds such as anthracene. Pyrene, Phenanthrene or corones, or nitrogen-containing cyclic compounds such as indole, carbazole, isoxazole.thiazole. Imidazo !, pyrazole. Oxadiazole, thiadiazole or triazole; specific examples are

Hexamethylenediamine,

N- (4-aminobutyl) -cadaverine,

asym-didodecylhydrazine, p-toluidine, 4-amino-o-.iylene, N, N'-diphenyl-1,2-diaminoethane.

o-, m- or p-Ditolylamine.Triphenylamine.

Triphenylmethane,

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

Durol, 2-bromo-3,7-dimethyl naphthalene.

23,5-trimethylnaphthalene,

N '- (3-bromophenyl) -N - (/? - naphthyl) urea, N'-methyl-N - (* - naphthyl) urea.

N.N'-diethyl-N - («- naphthyl) urea, 2,6-dimethylanthracene, anthracene, 2-phenylanthracene, 9,10-diphenylanthracene, 9,9'-bianthranil, 2-dimethylaminoanthracene.

Phenanthrene, 9-aminophenanthrene, 3.6-dimethylphenanthrene,

5.7-dibromo-2-phenylindole, 23-dimethylindoline, 3-indolylmethylamine, carbazole, 2-methylcarbazole.

N-ethylcarbazole, p-phenylcarbazole,

Ι.Γ-dicarbazole, 3- (p-methoxyphenyl) oxazolidine. 3,4,5-trimethylisoxazole,
2-anilino-4,5-diphenylthiazole.
2,4,5-Triaminophcny! Imidazo !,
4- amino-3,5-dimethyl-1-phenylpyrazole,
2,5-diphenyl-1,3,4-oxadiazole,
! , 3.5-triphenyl-1,2,4-triazole,
l-amino-5-phenyltetrazole and
Bis-diethylaminophenyl-1,3,6-oxadiazole.

High molecular donors (group E)

Poly-N-vinylcarbazole and its derivatives, e.g. B. such with halogen atoms, such as chlorine or bromine, and substituents, such as methyl or amino, on the carbazole structure; Polyvinyl pyrene. Polyvinyl anthracene, pyrene formaldehyde condensation polymers and their derivatives, e.g. B. those with halogen atoms, such as bromine, and substituents. like nitro, on the pyrene structure.

P photoconductors which can be used according to the invention are z. B. amorphous Se and phthalocyanine pigments. According to the invention Usable N-photoliter are e.g. zinc oxide and cadmium sulfide.

For the charge generating substance in combination 1, a suitable molar ratio in the case of the combination of donor and acceptor is about 1: 1, while in the case of a combination of non-coloring pigment and dye, a suitable weight ratio of dye to pigment is 0.3 to IO ~ ⁵ . In combination 2 mentioned above, the weight ratio of N photoconductor to P photoconductor is preferably 1: 0.1 to 10, while the weight ratio of acceptor to donor is preferably 1: 0.1 to 10.

The first and / or second photoconductive layer, which may or may not be positively-negatively chargeable, one can add a binder or a plasticizer or a spectral sensitizer of group B and / or chemical sensitizers of groups C and D to the sensitivity ranges of these to delimit photoconductive layers from one another. The amounts mentioned below can be used here.
The amount of colorants of group A or A 'which can be used in the first and second photoconductive layers is expediently 1 to 70 percent by weight, preferably 5 to 40 percent by weight, with evaporation products such as Se. and Se alloys within the percentage of 100 can be used. The weight share! of the total composition, including the coloring or non-quenching pigments and spectral sensitizers of group B or chemical sensitizers of groups C and D. on the photoconductive layer, should be less than 70 percent by weight, the remainder being made up of high molecular weight donors of group E. which are also called Binding agents act, or consists of conventional binding agents, e.g. B. polyethylene, polystyrene, polybutadiene, styrene-butadiene copolymers, acrylate or methacrylate polymers or copolymers, polyester, polyamide, polyimide, polycarbonate, epoxy resins, urethane resins, silicone resins, alkyd resins, vinyl resins such as polyvinyl chloride. Polyvinyl acetate or polyvinyl pyrrolidone, cellulose resins. like nitrocellulose or acetylcellulose,

b5 or mixtures of these resins. The plasticizer, like Dibutyl phthalate, or dioctyl phthalate, can be used in an amount below 30 percent by weight, based on the photoconductive Layer, can be added.

25th

30th

According to the invention usable positively-negatively chargeable photoconductive layers are, for. B. Layers with a combination of substances from group C and substances from groups D or E, preferably of group E, for example photoconductive layers made of substances that form a charge transfer complex 2,4,7-trinitrofluorenone of group C and poly-N-vinylcarba ^ d of group E form photoconductive layers which are a combination of a substance from group A (or A ') or group B with one of the Groups D or E contain; photoconductive layers with a cocrystalline complex of a pyrylium dye, e.g. B. a pyrylium, thiapyrylium or selenapyrylium salt, together with a group D triphenylmethane derivative; and photoconductive layers th simultaneously containing two or more kinds of substances of group A (or A '), such as zinc oxide or Copper phthalocyanine. contain. Furthermore, these semi-conductive layers can be laminated from a charge-generating and a charge-transporting layer Layer can be formed, wherein the above photoconductive layers can be used as a charge generating layer on which a charge transporting layer in which the compound of group C, D or E (ie, the charge transporting substance) is present in an amount of 30 to 95% by weight is laminated is and the rest from the above mentioned usual binders and plasticizers. The charge generating layer can in this Fall by vapor deposition or spraying on an inorganic. η group A photoconductive substance, e.g. B. amorphous selenium, and an organic photoconductive substance, e.g. B. Cu phthalocyanine, or in the form a laminate containing the photoconductive layer used as a charge generating layer from the cocrystalline complex and one applied to it. Charge transport layer includes, the from the triphenylmethane derivative belonging to group D, e.g. bis-diethylaminophenyl-1,3,6-oxa-

diazole, and a substance from group E or a conventional binder, such as poly-N-vinylcarbazole or Polyester resin.

The first and second photoconductive layers are obtained by adding the above-mentioned components of each layer e.g. B. in toluene, tetrahydrofuran, 1,2-dichloroethane, benzene or methanol dissolves or disperses and the organic solution obtained on the conductive support or the first photoconductive layer in a conventional manner, for. B. by means of air brush, knife or dip coating, applies and dries.

In order to make the first photoconductive layer 12 capable of commutation with respect to the support, can the substrate and / or the photoconductive layer consist of the following specific materials: Photoconductive Se layer evaporated on an Al plate under specific conditions; on a conductive substrate or layer made of a metal with a work function of 4.7 eV or more, such as Pt Au or Pd, vapor-deposited As2Se3; as well as one on a CuJ-conductive substrate formed layer of ω a cocrystalline complex.

Using a metal with a work function of 4.7 eV or more enables injection of positive or negative charges during the first charging from the support into the first photoconductive layer, whereby a high electrical potential is obtained which can selectively separate the colors from one another.

The recording material according to the invention described so far is a multilayer material with first and second photoconductive layers. Even if one of these layers is positive-negative-chargeable or commutatable. the first photoconductive layer must be at least sensitive to the chromatic light A, while the second photoconductive layer transmits this chromatic light A and is sensitive to the chromatic light B. Assuming that the chromatic light A red light and the chromatic light B is a non-red, visible light, the photoconductive layers, which are sensitive to the respective light, can like be classified as follows:

a) Red-sensitive photoconductive layer (A £ 600 nm)

Photoconductive layers using photoconductive blue substances such as Diana blue (Cl 21 180) (as organic azo pigment), indigo (as indigo pigment) or copper phthalocyanine (as phthalocyanine pigment) from group A; photoconductive Layers that use blue dyes as spectral sensitizers for the photoconductive substances, e.g. methylene blue (Cl 52 015), thiazine dyes, 13.5-triphenylthiapyrylium perchlorate, tetrabromophenol blue or pyrylium dyes of group B, where z. B. the spectral sensitization of polyvinyl carbazole with these pyrylium dyes and the spectral sensitization of zinc oxide with tetrabromophenol blue or Triphenylmethane dyes takes place; and photoconductive layers containing cocrystalline complexes of pyrylium dyes and polycarbonates.

b) non-red-sensitive photoconductive layer (A < 600 nm)

Photoconductive layers using different

organic photoconductive substances such as amorphous Se. Cadmium sulfide, cadmium selenide, zinc oxide, Zinc sulfide or titanium dioxide (especially rutile), or yellow or red organic photoconductive substances, such as Algolgelb (Cl Basic Yellow 4) (quinone pigment ment), Indo Fast Orange toner (Cl Vat Orange 3) (bisbenzimidazole pigment), quinacridone pigments or some of the perylene pigments from Group 1; photoconductive layers that act as spectral sensitizers for the photoconductive substances yellow and red dyes included, e.g. B. Oramin (Cl 41,000 B) (diphenylmethane dye). Fluorescein (CI 45 350) or Rose Bengal (Cl 45 435) (xanthene dyes acridine orange (CI 46 005) or acridine yellow (CI Basic Yellow 4) (acridine dyes), e.g. those that are sensitized to zinc oxide obtained with rose bengal; as well as photoconductive layers which, as starting materials, use weak charge transfer complexes of poly-N-vinylcarbazole or Pyrene-formaldehyde capacitors among the substances of group E and z. B. 2,6-Dinitrofluorcnon among the substances of group C contain.

c) Red and non-red sensitive photoconductive layer

(c-1) Inorganic photoconductive layers containing copper-doped cadmium sulfide, As- or Te-doped amorphous selenium or As2Se2, and

ίο

(c-2) photoconductive layers used as starting materials strong charge transfer complexes from combinations of 2,4,7-trinitrofluorenone and 3,6-Dinitrofluorenon-ivlandelsäurenitril among the Group C substances with poly-N-vinylcarbazole and pyrene-formaldehyde condensates among the group E substances.

For the two photoconductive layer 14, either a) or b) is used. In contrast, either c) or b) is used for the first photoconductive layer 12 used when the second photoconductive layer 14 is a), or the first layer is a) when the second Layer 14 b) is.

Further, the photoconductive layers can have positive-negative chargeability under the following conditions using the specific wavelength absorption (wavelength separation or color sensitivity) or a commutation ability with respect to the substrate can be imparted.

If the second photoconductive layer is red-sensitive and positively-negatively chargeable and the first photoconductive Layer is not sensitive to red. can be a combination of a second photoconductive layer of two or more can be used.

In order, if necessary, to regulate the color sensitivity of the first photoconductive layer, the intermediate layer can contain an inorganic compound such as sulfur, barium chromate, barium bichromate, tin oxide, cesium oxide, cesium sulfide, chromium oxide, cobalt chloride, cobalt sulfate, indium sulfate, iron bromide, hexacyanoferrate II or III. Molybdenum chloride, nickel chloride, tin iodide or tin sulfide, or an organic colorant such as Hansa yellow (CI 11 680), benzidine yellow (Cl 21 095), permanent red (CI 12 120), benzidine orange (CI 21 110), Brilliant real scarlet (Cl 12 315), Watching Red (Cl Pigment Red 48), Lake Red (Cl Pigment Red 53) or Lithol Red (Cl Pigment Red 53) can be added. Furthermore, substances of groups A and B can be added to the intermediate layer or applied by vapor deposition or spraying processes to form the intermediate layer.
When the light B is red light, blue pigments or dyes are used; on the other hand, if the light B is a non-red light, then red pigments or dyes are used. In the intermediate layer 13, dyes are more effective than pigments because they are more uniformly dissolved or dispersed than the particulate pigments.

a cocrystalline complex with a polyarylalkane, 25 can be yawed, reducing the thickness of the layer im z. B. triphenylmethane derivatives, or a blue Pig- compared to the use of pigments reduced

ment, ζ. B. Cu phthalocyanine, with an acceptor such as 2,4,7-trinitrofluorenone, use. As the first photoconductive layer in this case, there can be used those mentioned above Use substances with non-red sensitivity, e.g. B. Se or zinc sulfide.

Without the use of an intermediate layer, there is a risk that free charges will move from the first to the second photoconductive layer or vice versa, depending on their combination. This hinders training individual electrostatic areas with opposite polarity in the first and second, respectively Phoioieiuähigen layer if the one described below Two-color copying process is carried out.

This problem is avoided by the intermediate layer according to the invention. Also in this Interlayer when copying repeatedly after the end of the exposure no residual charge remains, the The charge captured and stored by this layer during the electrical charge is intended for renewed exposure to be easily degraded and the ability to take up a surface potential should can be decreased so that it does not affect the development time.

For this purpose, the intermediate layer preferably has a high specific inductive capacitance as well a small layer thickness.

To allow the injection of free charges between the can be.

The thickness of the intermediate layer 13 varies somewhat depending on the kinds of raw materials used therein. however, is usually 0.01 to 10 μίτι. preferably 0.1 to 3 μm. That to manufacture Organic solvents used in the recording material according to the invention should be the binder can solve and is z. B. toluene. Tetrahydrofuran.

1,2-dichloroethane, benzene or methanol.

The recording material according to the invention is produced by using a conductor with a specific resistance of less than 10 ¹⁰ ohm · cm, e.g. B. a metal plate made of Al. Cu or Pb. one is a metal oxide such as SnO ₂ , In ₁ O ₃ , CuO. or CuO ₂ , containing plate or substrate made of glass. Paper or a plastic film is used, the surface of which has been coated with the compound by vapor deposition or spraying. Then z. B. applied by coating or vapor deposition, a first photoconductive layer, an intermediate layer and a second photoconductive layer. The thickness of the first photoconductive layer is usually 3 to 180 μίτι. preferably 5 to 150 μm. The thickness of the second photoconductive layer is usually from 3 to 50 μm, preferably from 5 to 30 μm, and the thickness of the intermediate layer corresponds to the values mentioned above.

The recording material thus obtained enables

In order to prevent photoconductive layers, the intermediate 55, in comparison to recording materials, should only be produced from the layer by applying a solution in a conductive layer support 11 with solvent applied to it. The intermediate layer
consists essentially of a high molecular weight

cationic or anionic electrolytes. Suitable most and second photoconductive layers 12 and 14, respectively, however, excellent results without an intermediate layer, presumably because of the injection of

cationic Eiektroiyte are z. B. Polyvinylbenzyltrime- 60 excess charge in the first or second photo-

thylammonium chloride, poly-N-methyl-4-vinylpyridium chloride and poly-2-methacryloxyethyltrimethylammonium chloride. Suitable anionische Eiektroiyte are z. B. Sodium polymethyl acrylate, sodium polystyrene sulfonate Sodium vinyl phosphate, polyglycidyl tributyl sulfonium chloride and poly-2-acryloxy ester dimethyl sulfonium chloride. These high molecular weight cationic or anionic electrolytes can be used individually or as mixtures conductive layer is prevented by the electrical insulation or commutation, so that the charge distribution can be properly maintained between the first and second photoconductive layers can.

The recording material of the present invention can be used in the following three electrophotographic recording methods can be used:

Procedure I.

The electrophographic used in this procedure Recording material comprises a first photoconductive layer 12 sensitive to Light A and a second photoconductive layer 14 which transmits light A and is sensitive to light B.

First, the first photoconductive layer 12 has a first positive or negative corona charge opposite polarity to their sensitivity or with a polarity opposite to the charge, injected into the first photoconductive layer 12 from the substrate 11, and then uniformly exposed only to light A or a light containing light A but not light B. This uniform Exposure can take place at the same time as the first charge; however, if the first layer 12 is injected Charge from the substrate 11 is to take up during the first charge, then this can be done in the dark take place with omission of the uniform exposure (Fig.2-a).

The light image of the original 2 is then charged with a second corona of opposite polarity projected onto the recording material for initial charging. In this case, the second charge takes place with a slightly lower electrical potential than the first charge. The black one learns about it Area of the original 2 corresponding part of the recording material no change in the charge distribution, while the charge distribution in the Part of the recording material corresponding to the white area of the original is changed so that both the first and second photoconductive Layer 12 or 14 become conductive and the charge is reduced there. On the other hand, in the part of the Recording material corresponding to the color range of the original 2, e.g. B. the color area A, on the second photoconductive layer part of the charge (Fig. 2-c), although the first layer 12 is made conductive became. Electrostatic latent images are thus formed on each of the photoconductive layers 12 and 14, which correspond to the black or colored areas of the original 2 and have different polarities to have. These latent images are sequentially created with a color toner 3 and a black toner 4 developed to give a two-color copy (Fig. 2-d). F i g. 3 shows the time course of the surface potential of the recording material.

Above, the polarity of the first charge is negative and that of the second charge is positive, however the same results are obtained with reversed charge polarity.

Procedure II

The recording material used in this process comprises a first photoconductive one opposite Light B sensitive layer 12 and a second layer 14 which transmits light B and is sensitive to light A. is

This material is a first positive or negative corona charge with the same polarity, against which the second layer 14 is sensitive. subjected. Simultaneously with or immediately after charging the uniform exposure to light A takes place in order to make the second layer 14 conductive. But when the second layer 14 is capable of charge transport during the first charging, the first charging in the dark, omitting the uniform exposure (Fig. 4-a).

The recording material is then subjected to a second corona charge with opposite polarity to that of the first charge (Fig. 4-b) and the photograph of the original is transferred to the Transferred recording material, in this case takes place / far charging with slightly lower electrical Potential as the first charge. The one corresponding to the black area of the original 2 is subject to this Part of the recording material shows no change in the charge distribution, but this changes in the part corresponding to the white area of the original and makes the first and second layer 12 or 14 conductive, whereby the charge is diverted there. Although the second photoconductive Layer 14 has been made conductive, remains in the part corresponding to the colored area of the original 2 of the recording material, e.g. B. the color area A, some of the charge on the first photoconductive Layer back (Fig. 4-c). Thus, on the recording material electrostatic latent images corresponding to the black and colored areas of the Originals 2 generated, which have different polarity from each other. These are one after the other with a colored toner 3 and a black toner 4, thereby producing a two-color copy (Fig. 4-d). This method has the advantage that the black image area has the shape of an external latent Image, d. H. the latent image is formed on the second photoconductive layer. F i g. 5 shows the temporal Course of the surface potential of the recording material in this process.

Procedure III

The recording material used in this method comprises a first photoconductive layer 12 which is sensitive to light B and is amenable to injection of charges of a certain polarity during charging, and a second photoconductive layer 14 which transmits light B and is sensitive to light A. .
In the dark, this recording material is exposed to a first corona charge of opposite polarity to that of the charge which is injected from the substrate 11 into the first layer 12 and to which the second layer 14 is sensitive (FIG. 6-a). Then, the recording material is subjected to a second corona charging of opposite polarity to that of the first charging (Fig. 6-b), whereupon the light image of the original 2 is transferred onto the recording material. In this case, the second charge takes place with a slightly lower electrical potential than the first charge. The part of the recording material corresponding to the black area of the original 2 is not subject to any change in the charge distribution, but changes in the part corresponding to the white area of the original, whereby the first and second photoconductive layers 12 and 14 become conductive and the charge there is derived. Although the second layer 14 is made conductive, remains in the part of the recording material corresponding to the colored area of the original 2, e.g. B. the color area A, part of the charge on the first photoconductive layer (Fig. 6-c). Thus, electrostatic latent images are formed on the recording material

correspond to the black or colored areas of the original and each have a different polarity. These latent images can be sequentially applied with a color toner 3 and a black toner 4 and provide a two-color copy (Fig. 6-d). This method has the advantages that the black image area takes the form of an external latent image F i g. 7 shows the time course of the Surface potential of the recording material in this process.

In explaining the above three methods, the polarity of the first charge was negative and that of the second charge positive. However, under otherwise identical conditions, the same results can also be achieved with reversed charge polarity.

The recording material according to the invention is not only> n the described processes I, 11 and III, but can also be used in the conventional Carlson process. The original used needs to be used not being a two-tone original as above, but it can have three or more colors. He follows copying with this multi-color original by the two-color copying process described above, see above a two-color copy is obtained, but a color shading occurs between the respective color areas monochromatic Carlson process, a black-and-white copy is obtained with significantly different image density between the respective color areas.

In the following examples, all parts refer to on weight

example 1

Selenium is evaporated to a thickness of about 60 μm as the first photoconductive layer on an aluminum plate as a conductive layer support. A solution of 10 parts of polystyrene sodium sulfonate in 90 parts of water is then applied by immersion and for 30 minutes at 50 ^° C. to form an intermediate layer of about 0.8 μπι thickness dried A solution of the following components is applied to this intermediate layer and dried to form a second photoconductive layer of about 12 μπι thickness.

subject, the surface potential being -980 V The material is then subjected to a second positive charge at +5.7 kV in the dark, whereupon the surface potential is +630 V. An image pattern with red, white and black image areas is irradiated with a 100 W tungsten lamp and the reflected light is projected onto the recording material through a lens system The resulting electrostatic latent image is stored in the

ίο Darkness with a two-component black developer and a two-component red developer developed and thus made visible The visible image is transferred to normal paper and fixed, whereby a clear, two-color, high density image which is free of mixed colors. For determining the charge potential and the dark decay If the copying process is repeated several times The following results are achieved:

Tabel

Inquiry state, V

Repetition several times. V

Charge potential

after first charge -980 -970

after a second charge +630 +620

Dark decay after 30 s after second charge 0.85 0.83

A comparison material without an intermediate layer and a first one are produced using the same method and subjected to second charging, whereupon the surface potential is -70 V and + 1370 V, respectively. With this material you get from the red-white-black Original a black copy, as red and white have been converted into white.

Example 2

A mixture of the following components is dispersed with stirring:

Poly-N-vinyl carbazole Pyrylium salt

10 parts 0.003 parts

Polyester resin Tetrahydrofuran

Part 1

!Part

10 parts

The mixture is applied with a doctor blade onto an aluminum plate and ^c 30 minutes at 100 C to a first photoconductive layer of about 40 μπι thickness is dried thereon with a doctor blade, a solution of 1 part Polyvinylbenzyltrimcthylammonium- chloride applied in 10 parts of methanol and dried for 1 minute at 100 ° C to form an intermediate layer of about 1 μm thick.

By dispersing with ultrasound, a solution of the following components is made:

Dibutyl phthalate Tetrahydrofuran

! Part 150 parts

The recording material obtained undergoes a first negative charge in the dark (- 6.3 kV)

ZnO 10 parts

Copper phthalocyanine 5 parts

Acrylic resin 15 parts of tetrabromophenol blue

(1% solution in methanol) 2 parts

Toluene 200 parts This solution is dipped onto the intermediate

layer applied and dried for 10 minutes at 50 ⁰ C to a second photoconductive layer of about 15 μίτι thickness

The recording material obtained is subjected to a first negative charge (−63 kV) in the dark, while at the same time it is exposed through a red filter with a 100 W tungsten lamp. The surface potential of the material is at this stage -740 V. The material is then subjected to a second positive charge in the dark (+5.7 kV), whereupon its surface potential is + 540V.

According to Example 1, an electrostatic latent Image generated, developed, transferred to ordinary paper and fixed to obtain a two-color copy of high image density free from mixed colors. To After repeated copying, practically the same results as in Example 1 are obtained

A comparison material without an intermediate layer and a first one are produced using the same method and subjected to second charging, whereupon the surface potential is -100 V and + 1180V respectively Off the red-white-black original is a copy with a black color image, because red and white in Have been converted to white.

Example 3

By vapor deposition of a Se-Te alloy (Te-Gehah 6 percent by weight) on an aluminum substrate is a first photoconductive layer of about 50 μπι Thickness produced A solution of the following components is then applied and an intermediate potential is obtained which is -700 V After exposure to light from a tungsten lamp (radiant energy on the drum: approx. 5 μJ) through a red filter and a slit of 8 mm, the surface potential of the recording material is +450 V.

Example 4

On an aluminum substrate, a Se-Te alloy (Te content 6% by weight) is the first photoconductive capable layer in a thickness of about 50 μπι vapor-deposited. A solution of the following is then applied Components on and receives an intermediate layer with a dry thickness of about 1 μπι:

Natnum-poly-L-glutamate 4 pieces H ₂ O 60Trih Methanol 40 parts

Then, a solution obtained by dispersing the following components in a ball mill is applied and dried to one Permeability of 40% at 570 μΐη:

Diana blue (CI 21 180) Polyester resin Tetrahydrofuran

2 parts

ITeil

120 parts.

On the obtained about 1.5 μπι thick layer of a solution of the following components is applied μπι having a slit width of 200 and dried at 50 ⁰ C to about 13 μπι thick layer:

layer with a dry thickness of et : waO, 7 μπι: N-methyl-N-phenylhydrazone 5 parts 35 S-methylidene-g-ethylcarbazoI 5.5 parts Sodium carboxymethyl cellulose 2 parts Polycarbonate 65 pieces H ₂ O 60 parts Methylene dichloride Methanol 40 parts

To produce a multilayer second photoconductive layer, one first forms an approximate 2 μm thick layer by applying a solution, which was obtained by dispersing the following components in a ball mill, to the intermediate layer and up to a permeability of 10% at 550 μm dries:

The recording material obtained is examined as in Example 3, but the radiation energy on the drum is 2.5 μ]. After the second charge, the surface potential is -620 V, after irradiation with red light +640 V.

For this purpose 2 sheets of drawings

/ -Copper-phthalocyamn 3 parts Polyester resin ITeil Ethylene dichloride 100 parts

Then an approximately 14 μm thick is formed Schichi »us by giving a solution to the following Components with a slot width of 200 μΐη the layer applies and dries at 50 * C:

2,5-bis (p-diethylaminophenyl) -13,4-oxadiazole 5 parts

Polycarbonate resin 55 parts Methylene dichloride 65 parts

The recording material obtained is mounted on a drum which moves at a linear speed of 100 mm / s and at a Voltage of - 6, okV charged. The surface potential of the material is at this stage - 24OOV. Then the recording material is charged with +43 kV, whereupon the surface DO-

Claims (3)

Patent claims: 1. Electrophotographic recording material with a conductive support on which a first photoconductive layer, which is at least against a portion A of the chromatic light of the visible range is sensitive, an intermediate layer and a second photoconductive layer which is transparent to the light of the portion A and opposite another sub-area B of the chromatic light is sensitive, are applied, wherein The two photoconductive layers are capable of each holding an electrostatic charge from one another opposite polarity bear and one for the development of a latent electrostatic Image of this electrostatic charge with a toner to assume sufficient surface potential and to preserve, characterized that the intermediate layer is essentially out of trouble! categorical or anionic high molecular weight Electrolyte is made up, capable of injecting free charges between the first and prevent the second photoconductive layer. 2. Recording material according to claim 1, characterized in that the cationic high molecular weight Electrolyte polyvinylbenzyltrimethylammonium chloride, Poly-N-methyl-4-vinylpyridium chloride and / or poly-2-methacryloxyäthyl-trimethylammoniumchlc'd is 3. Recording material according to claim 1, characterized in that the anionic high molecular weight Electrolyte sodium polyvinyl acrylate, sodium polystyrene sulfonate, sodium polyvinyl phosphate. Polyglycidyltributylsulfonium chloride and / or poly-2-acryloxyester dimethylsulfonium chloride.