DE1522677B2 - Electrophotographic process for making images - Google Patents

Description

OH

OH

R -

_lz

contains where R is a divalent group derived from formaldehyde. Paraformaldehyde, furfural, aminoformaldehyde, acrolein, benzaldehyde, chloral, a ketoaldehyde, acetaldehyde, glyoxal, propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-valeraldehyde, isovaleraldehyde, n-caproaldehyde, n-heptaldehyde, steraaldehyde and / or was formed equals an oxygen atom or the divalent group R, Y equals a hydrogen or halogen atom, an OH group and / or an alkyl group with 1 to 5 carbon atoms, η equals 1, 2, 3 or 4, m equals 1, 2 or 3 and Z is an integer of at least 2, or in which (Y), "denotes a phenyl group which is in the p-position to the OH group depicted in the formula, and in which (Y) _n for the case X is O denotes a phenyl group which is in the p-position to the radical X depicted in the formula.

3. The method according to claim 1, characterized in that a recording material with a Charge transfer complex is used, the 1 part by weight electron acceptor 1 to 100 parts by weight Contains electron donor.

55

The invention relates to an electrophotographic process for producing images in which on an electrophotographic recording material having a thermoplastic photoconductive layer a charge image is applied, which heats the recording material until a deformation image is formed and the deformation image is fixed by cooling. "

It is known to deformicrbarc dielectric materials to be used as a recording medium. In general, two different ones are used Procedure. The former is known as the so-called "frost" (wrinkle) method and is detailed in R. W. G u η d 1 a c h and C. J. C 1 ä u s, Journal of Photographic Science and Engineering, Jan./Feb. 1963, "A Cyclic Xerography Method based on Frost Deformation" is described. The other, as a "relief" method designated process is explained in detail in US Pat. Nos. 3,055,006, 3,063,872 and 3,113,179.

A fundamental difference between the "Frost" and the "Relief" methods is that So-called "frost" images are created in areas of even charge, while "relief" images create one correspond to electrostatic charge gradients.

This difference is not only significant with regard to the various possible applications, but also indicates a different mechanism for the two methods.

It is also of interest that "frost" structures can also be generated without taking in information can, while "relief" structures without information do not exist. The difference between the two systems is also caused by the fact that certain materials do are suitable for the formation of relief, but not for the formation of frost structures.

The object of the invention was to provide a new method for producing deformation images (Frostbzw. Wrinkled images and relief images). This object is achieved by the invention solved.

The invention thus relates to an electrophotographic process for the production of images, in which on an electrophotographic recording material having a thermoplastic photoconductive Layer applied a charge image, the recording material until a deformation image is formed heated and the deformation pattern is fixed by cooling, which is characterized by this is that a recording material having a photoconductive layer is used as Photoconductor a charge transfer complex from an electron acceptor and an optionally contains modified phenol-aldehyde resin.

The invention relates in particular to an electrophotographic method of the type mentioned at the beginning Type, which is characterized in that a recording material with a charge transfer complex which is a phenol-aldehyde resin of the formula

contains, where R is a divalent group consisting of formaldehyde, paraformaldehyde, furfural, Aminoformaldehyde, acrolein, benzaldehyde, chloral, a ketoaldehyde, acetaldehyde, glyoxal, propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-valcraldehyde, isovaleraldehyde, n-caproaldehyde, n-heplaldehyde, Steraldchyd and / or crotonaldehyde is formed, X equals an oxygen atom or the divalent group R, Y is a hydrogen or halogen atom, an OH group and / or a

lower alkyl group, Z is an integer of at least 2, η is 1, 2, 3 or 4 and m is 1, 2 or 3. The phenol-aldehyde resin used in the present invention preferably has a molecular weight of at least about 300.

The inventive method enables the simple and rapid production of excellent Deformation images. If transparent photoconductors are used, the images obtained can be used in Projection devices are considered.

In the method according to the invention, the deformation can take place simultaneously or after the exposure. During the deformation, a layer of increased and decreased layer thickness is created on the surface composite pattern that is the pattern of the original with light and dark areas is equivalent to. The softening or thermal deformation of the photoconductor used according to the invention can by heat, but also by solvent vapor or other suitable means. The one in the present Description used term »deformable« or »heat deformable« refers to these measures.

The method according to the invention for producing deformation images is carried out generally in several process steps; these include: applying a latent electrostatic Image or a charge pattern on an insulating layer made of one described in detail above Material that can be softened by heat or solvent vapors. The layer can then be softened until the electrostatic attractive forces of the charge pattern are greater are than the surface tension of the layer.

As soon as this limit is reached, numerous very small wrinkles form on the surface of the layer and wrinkles, the depth of the wrinkles in the individual areas of the layer being dependent on the amount of charge is dependent in these areas. This gives the image the appearance of a “frozen image”. The insulating layer can already be softened before the charge pattern is applied will; A prerequisite for this, however, is that the insulation properties of the material are to be maintained sufficient for the load. The "freezing" of the image can then be done by letting the layer harden done by allowing the layer to return to the state it was exposed to before softening was.

If such a "freezing" system is to be used repeatedly, it is desirable that the images produced by freezing after hardening by re-softening the layer can be removed again. For this purpose it is necessary that the viscosity of the thermoplastic Material can be lowered so far for a long enough time that smoothing of the layer through the surface tension can take place.

Such materials are to be particularly suitable for use in the aforementioned systems name that are not only characterized by sufficient deformability, but also that are good photoconductors. In this way it is possible to place these materials directly on a conductive surface to be applied without a photoconductive intermediate layer required according to the prior art necessary is.

Neither of the above two components used to make the photoconductive material is photoconductive in itself; rather, both components are non-conductive. By transferring a non-photoconductive Lewis acid and a non-photoconductive thermoplastic phenol-aldehyde resin in a complex compound, an insulating material having excellent photoconductive properties is obtained Properties which are applied to a conductive support by a suitable method known per se and thus forms a recording material deformable by heat. In addition there is the ability to deform the photoconductive material into a self-supporting layer; the previously described There is then no need to apply it to a base. It can also be used on the photoconductor second, heat-deformable coating can be applied.

It is important that the heat-deformable layer has a specific electrical resistance of ΙΟ ¹⁰ ohm · cm or more and a viscosity of up to about 10 ⁶ poise at its softening point. The heat-deformable layer can have a layer thickness of up to about 300 microns however, the most favorable values are in the range of 5 to 15 microns. The mixing ratio of phenol-aldehyde resin to Lewis acid can be chosen so that about 1 to 100 parts of phenol-aldehyde resin are used for 1 part Lewis acid. For optimum sensitivity, it is preferred to use about 1 to 5 parts of phenol-aldehyde resin per 1 part of Lewis acid. The image can be generated by any suitable method. Typical procedures are summarized below:

1. The thermoplastic photoconductive layer is first charged uniformly and then selectively exposed according to the image to be reproduced. Subsequently, the material undergoes a heat treatment subject and to the formation of a deformation pattern, the configuration of which corresponds to the pattern of previous selective exposure, deformed. The image is then fixed by pressing the Layer is allowed to cool.

2. In another method, the thermoplastic layer is selectively made according to a predetermined one Pattern charged, for example by means of a corona discharge using a Stencil or by charge transfer from a second photoconductor. The material is then heated, whereby a selective deformation of the layer takes place only in the areas that were originally with had been charged.

3. Another method is to coat the photoconductive layer with a thermoplastic material. The material produced in this way is provided with a uniform charge and accordingly exposed to the image to be reproduced. A uniform charge is then applied again. The material is then heated and deformed in the manner described above. You get so a negative deformation image, d. H. Black for white.

4. In another method, the photoconductive thermoplastic material comes in the form of a self-supporting film for application. The film is given away with a charge by placing between a pair of corona discharge devices. This is followed by a selective one Exposure of the film according to a

producing image, which is then deformed by heating. The deformation image obtained in this way corresponds to the original used for exposure. In this way, a light-refracting image can be created on a transparent film, which is devices can be used.

5. Will the non-charge recording material imaged by any of the above methods again subjected to heat treatment until the softening point is reached, the surface tension smooths the surface and removes the image. The photoconductive one Material is then ready to be used again by one of the methods mentioned.

6. In the method according to the invention, all those described in GB-PSs 11 22 001 and 11 22 002 can be used Procedures are applied.

The methods used in each case for generating deformation images can be found in Can be varied depending on the particular requirements. In certain cases z. B. the thermally deformable layer prior to applying a uniform charge to the surface be subjected to a pretreatment. You can also use many different methods of fixing and / or removing the material can be applied according to a predetermined image. ^ _ -

In the present description, each is in with respect to the phenol-aldehyde resin to be complexed therewith as an electron acceptor material referred to as "Lewis acid". A charge transfer complex can as a non-polar, essentially neutral electron donor or electron acceptor molecules complex formed are defined, which is characterized by the fact that an internal electron transfer is caused by photoexcitation which temporarily creates an excited state in which the donor is more positive and the acceptor is more negative than in the ground state.

It is believed that the insulating phenol-aldehyde resins used in the invention from Donor type their photoconductivity through the formation of charge transfer complexes with electron acceptors (Lewis acids) and that these complexes, once formed, the form the photoconductive element of the recording materials.

Charge transfer complexes are generally loose associations of electron donors and Electron acceptors, which are often contained in the complexes in stoichiometric proportions. They can be characterized as follows:

A. The donor-acceptor reaction is only weak in the neutral ground state; d. i.e., neither the Donor and acceptor are noticeably disturbed by the partner as long as there is no stimulation takes place through the action of photo energy.

B. The donor-acceptor reaction is relatively strong in the excited state; i.e., the components are at least partially ionized by the action of radiant energy.

C. Once the complex is formed, one or more new absorption bands appear nearby Ultraviolet or in the visible spectral range (wavelengths between 3200 and 7500 Angstroms), which were not present in either the donor or the acceptor, but a specific one Represent property of the donor-acceptor complex formed.

It was found that the photoconductivity is based on both the specific bands of the donor and also the bands of the complex based on a charge transfer.

The term "photoconductive insulator" is used in the context of the present invention in relation to the practical application in electrophotography. In general, virtually any isolator can be used in are brought into a photoconductive state; all that is required for this is excitation by radiation sufficient intensity and sufficiently short wavelength. This fact applies to both inorganic as well as organic materials including inert resin binders such as those used for binder boards are used, and activators of the electron acceptor type used according to the invention and the thermoplastic phenol-aldehyde resins also used in accordance with the invention. The sensitivity for very short-wave radiation, however, is for practical use in electrophotography not usable because radiation sources of sufficient intensity door wavelengths below 3200 angstroms are not accessible, especially since such radiation is harmful to the human eye and is also absorbed by optical systems made of glass. Accordingly, according to the teaching According to the invention, “photoconductive insulators” are understood to mean only those materials which are characterized as follows can be:

1. These materials can be used to form coherent layers or films that are in the Are able to retain an electrostatic charge in the absence of actinic radiation.

2. When exposed to radiation whose wavelength is greater than 3200 angstroms, these layers or films show a sensitivity which is sufficient to reduce at least half of the charge present with a total flux of at most 10 ¹⁴ quanta per cm ² .

According to this definition, the resins and Lewis acids used according to the invention are so far used individually, excluded from the class of photoconductive insulators.

Practically all phenol-aldehyde resins can be used in the process according to the invention, the selection of these thermoplastic materials depends only on the intended use and the required properties.

Specific examples of phenols useful in making phenol-aldehyde resins are Phenol, cresol, xylene, alkylphenols, such as p-tert-amylphenol, p-cyclohexylphenol, arylphenols, such as p-phenylphenol and triphenyl-p-hydroxyphenol, alkenylphenols, such as o- and p-1,5-di- and 1,3-dibutenylphenol and 1,3,5-tributenylphenol, halogenated Phenols such as mono-, di-, tri- and tetrachlorophenol, resorcinol, hydroquinone and mixtures thereof; sulfonated Phenols, such as p-hydroxy-tert-butylbenzenesulfonic acid, di-, tri- and polyhydric phenols such as resorcinol, hydroquinone, catechol, pyrogallol,

Phloroglucinol, benzenetriol and xylenol, polynuclear phenols such as «- and / i-naphthol, anthracene phenol, Dihydroxydiphenylalkanes, such as bisphenol A, and mixtures thereof.

Any of the aforementioned can also be used to produce the phenol-aldehyde resins which can be used according to the invention Substituted phenol corresponding to phenols can be used. In addition, if desired, the phenol-aldehyde resin used is modified phenol-formaldehyde resins, for example, can be modified with diphenyl oxide. In this way, a phenol-formaldehyde resin is obtained, which is between at least one aromatic Group has an oxygen bridge.

Virtually any suitable aldehyde can be used to react with the phenol. Specific Examples of such aldehydes are formaldehyde, paraformaldehyde, furfural, aminoformaldehyde, acrolein, Benzaldehyde, chloral, ketoaldehyde, acetaldehyde, glyoxal, propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-valeraldehyde, isovaleraldehyde, n-caproaldehyde, n-heptaldehyde, stearaldehyde, crotonaldehyde and mixtures thereof.

Virtually any Lewis acid can be used to produce the photoconductors used according to the invention complexed with one of the phenol-aldehyde resins mentioned above.

Although the mechanism of complex formation is not yet fully understood, it can be assumed be that a charge transfer complex is formed which has absorption bands, which are not characteristic of any of the complex-forming components, if these are present individually. The synergistic effect created by mixing the two non-photoconductive components seems to be much greater than that through a pure addition of the properties of the individual Components to achieve effect.

The best results are achieved with the following preferred Lewis acids. These include 2,4,7-trinitro-9-fluorenone, 4,4-bis (dimethylamino) benzophenone, Tetrachlorophthalic anhydride, chloranil, picric acid, benz (a) anthracene-7,12-dione, and 1,3,5-trinitrobenzene.

Specific examples of other Lewis acids used according to the invention are quinones, such as p-benzoquinone, 2,5-dichlorobenzoquinone, 2,6-dichlorobenzoquinone, naphthoquinones 1,4), 2,3-dichloronaphthoquinone- (1,4), Anthraquinone, 2-methylanthraquinone, 1,4-dimethylanthraquinone, l-chloranthraquinone ^ anthraquinone-2-carboxylic acid, 1, S-dichloroanthraquinone, 1 -Chlor-4-nitroanthraquinone, phenanthrenequinone, acenaphthenquinone, pyranthrenequinone, chrysenequinone, Thionaphthenquinone, anthraquinone-1,8-disulfonic acid and anthraquinone-2-aldehyde, triphthaloylbenzene, Aldehydes, such as bromal, 4-nitrobenzaldehyde, 2,6-dichlorobenzaldehyde, 2-ethoxy-1-naphthaldehyde, Anthracene-9-aldehyde, pyrene-3-aldehyde, oxindole-3-aldehyde, Pyridine-2,6-dialdehyde and biphenyl-4-aldehyde, organic phosphonic acids such as 4-chloro-3-nitrobenzenesophosphonic acid, Nitrophenols, such as 4-nitrophenol and picric acid, acid anhydrides, such as acetic anhydride, Succinic anhydride, maleic anhydride, phthalic anhydride, tetrachlorophthalic anhydride, Perylene-O ^ .lO-tetracarboxylic acid, chrysene-2,3,8,9 -Tetracarboxylic anhydride and dibromomaleic anhydride; Halides of metals and metalloids of groups IB, II to VIII of the periodic table of elements, such as aluminum chloride, zinc chloride, Iron (III) chloride, tin (IV) chloride, arsenic trichloride, Tin (II) chloride, antimony pentachloride, magnesium chloride, magnesium bromide calcium bromide, Calcium iodide, strontium bromide, chromium (III) bromide, manganese (II) chloride, cobalt (II) chloride, cobalt (III) chloride, Copper (II) bromide, cerium (IV) chloride, thorium chloride, arsenic triiodide and boron halides, such as boron trifluoride and boron trichloride, and ketones such as acetophenone, benzophenone, 2-acetylnaphthalene, benzil, Benzoin, 5-benzoylacenaphthene, biacendione, 9-acetylanthracene, 9-benzoylanthracene, 4- (4-dimethylaminocinnamoyl) -l-acetylbenzene, Acetoacetic anilide, indanedione (1,3), acenaphthenequinone dichloride, anisil, 2,2-pyridil and furil.

Other Lewis acids are mineral acids, such as the hydrohalic acids sulfuric acid and phosphoric acid, Carboxylic acids, such as acetic acid and its substitution products, monochloroacetic acid, dichloroacetic acid, Trichloroacetic acid, phenylacetic acid and 6-methylcoumarinyl acetic acid- (4), maleic acid, cinnamic acid, Benzoic acid, l- (4-diethylaminobenzoyl) -benzene-2-carboxylic acid, phthalic acid and tetrachlorophthalic acid, a ^ -dibromo-ß-formyl-acrylic acid (mucobromic acid), Dibromomaleic acid, 2-bromobenzoic acid, gallic acid, 3-nitro-2-hydroxy-l-benzoic acid, 2-nitrophenoxyacetic acid, 2-nitrobenzoic acid, 3-nitroben-J._jzoic acid, 4-nitrobenzoic acid; ' 3-nitro-4-ethoxybenzoic acid, 2-chloro-4-nitro-1-benzoic acid, 3-nitro-4 - methoxybenzoic acid, 4 - nitro -1 - methylbenzoic acid, 2-chloro-5-nitro-1-benzoic acid, 3-chloro-6-nitro-1 benzoic acid, 4-chloro-3-nitro-1-benzoic acid, 5-chloro-3-nitro-2-hydroxybenzoic acid, 4-chloro-2-hydroxybenzoic acid, 2,4 - Dinitro - 1 - benzoic acid, 2-bromo-5-nitrobenzoic acid, 4-chlorophenylacetic acid, 2-chlorocinnamic acid, 2-cyanocinnamic acid, 2,4-dichlorobenzoic acid, 3,5-dinitrobenzoic acid, 3,5-dinitrosalicic acid, malonic acid, mucic acid, acetosalicylic acid, Benzilic acid, butanetetracarboxylic acid, citric acid, cyanoacetic acid, cyclohexanedicarboxylic acid, cyclohexanecarboxylic acid, 9,10-dichlorostearic acid, fumaric acid, itaconic acid, levulinic acid, malic acid, succinic acid, α-bromostearic acid, citraconic acid, dibromosuccinic acid, Pyrene-2,3,7,8-tetracarboxylic acid and tartaric acid, organic sulfonic acids such as 4-toluenesulfonic acid and benzenesulfonic acids, such as 2,4-dinitro-1-methylbenzene-6-sulfonic acid, 2,6-dinitro-1-hydroxybenzene-4-sulfonic acid, 2-nitro-1-hydroxybenzene-4-sulfonic acid, 4-nitro-1-hydroxy-2-benzenesulfonic acid, 3-nitro-2-methyl-1-hydroxybenzene-5-sulfonic acid, 6-nitro-4-methyl-1-hydroxybenzene-2-sulfonic acid, 4 - chloro - 1 - hydroxybenzene - 3 - sulfonic acid, 2 - chloro - 3 - nitro - 1 - methylbenzene - 5 - sulfonic acid and chloro-1-methyl-benzene-4-sulfonic acid.

The examples illustrate the invention. Parts and percentages are based on weight, unless nothing other is indicated.

Example I.

A sample of about 5 g of a diphenyl oxide modified novolak (pale amber solid, average molecular weight 1300, softening point 96 to 115) is placed in a 100 ml beaker containing about 45 g of a mixture of about 25 g of acetone and about 20 g of toluene ° C, specific weight 1.23 g / cm ³ ). This mixture is stirred with the aid of a magnetic stirrer until the resin has completely dissolved.

509513/286

Then about 250 mg of 2,4,7-trinitrofluorenone added to about 10 g of the aforesaid resin solution and the mixture is allowed to dissolve completely of the 2,4,7-trinitrofluorenone stirred.

The solution obtained in this way is then applied as a coating to a rectangular, highly polished aluminum foil with the dimensions 0.13 mm × 27.9 cm × 40.7 cm by means of a process known per se, such as brushing, dipping, pouring or spraying. The coating is then dried. The amount of the applied solution is chosen so that the layer thickness of the dried layer is about 5 μm. The plate provided with a coating in this way is provided with a negative charge of about 300 volts with the aid of a corona discharge. The plate is then exposed for 15 seconds. The exposure is effected by means of a projection enlarger equipped with a lens (focal length / = 4.5) and a tungsten lamp is provided with a color temperature of 2950 ⁰ K. The mean illuminance on the plate is about 43 lux as measured with a Weston illuminance meter.

The plate is then developed by applying on a heated substrate, wherein the substrate is maintained at a temperature of 100 ⁰ C.

When the plate is heated, it forms on the surface of the plate an image corresponding to the projected image, which is characterized by both good image resolution and also characterized by sharpness and by its ability to refract light and solid surface treatment. Once the plate is developed, it is removed from the heated plate and used to fix the Image cooled.

Example II

35

1 g of phenolic resin, which is produced by reacting about 1 mol of p-phenylphenol with less than 0.9 mol of formaldehyde is obtained in a 1: 1 ratio containing about 9 g of an acetone / toluene mixture Entered 50 mi beaker. This mixture is kept until the complete dissolution of the Resin stirred.

Then about 250 mg of 2,4,7-trinitro-9-fluorenone are added to the resin solution thus obtained, and the Mixture is stirred until all materials are evenly distributed.

The solution obtained in this way is then applied to an aluminum support, dried and stored in the im Example I described manner further treated. When the plate is heated, one also obtains in this case an image that corresponds to the projected image. Image sharpness, resolving power, light refraction properties and solid surface treatment also characterize this picture. Immediately after developing the plate is removed from the heated base and cooled to fix the image.

Example III

To produce a coating, a solution is prepared in the manner described in Example II, however, instead of the phenolic resin used in Example 11, a reaction of about 1 mole of p-tert-butylphenol and less than 1 mole Phenolic resin obtained from formaldehyde is used. Then the solution thus obtained is mixed with trinitrofluorenone added, and the solution is stirred. The solution thus obtained as a coating on an aluminum support is applied and the coating is dried. The plate produced in this way is as in the example I and II treated and shows practically the same properties as the plates according to the above Examples.

Example IV

A 4 μm thick coating of the mixture described in Example II is applied to an aluminum plate. The coating is dried and then coated with a further coating of a resin which is deformable by heat but is not photoconductive. This further coating consists of an approximately 10 percent strength by weight solution of a glycerol ester of hydrogenated rosin (hard, brittle solid, melting point 84 ° C., flash point 318 ° C., acid number 10 or less, specific weight 1.08 g / cm ³ ) in an aliphatic C ₆ - to Cjj hydrocarbon fraction. The thickness of the second coating is about 3 μm. The plate produced in this way is then dried.

The plate is then in the dark by means of a corona discharge with a negative charge of about 450 volts. The plate is then exposed for 15 seconds. The exposure takes place through Projection using a magnifier with a lens (focal length / = 4.5) and a tungsten lamp is equipped with a color temperature of 2950 ° K. The mean illuminance on the Plate is approximately 43 lux as measured with a Weston light meter. The plate is then again negatively charged and exposed to room lighting. Then the plate is through Laying on a surface kept at about 70 ° C developed. When the plate is heated, the Plate surface a negative image, d. H. Black for white of the projected image. This picture too is characterized by good resolution, image sharpness, refractive power and solid surface coating the end. Immediately after developing, the plate is removed from the heated surface removed and cooled to fix the image.

Example V

An aluminum plate is with a about 5 μΐη strong coating of a mixture composed according to Example II.

Subsequently, in the manner described above, a good refractive power due to image sharpness is achieved and solid surface coating produced an excellent image, which by cooling the plate after the developing is fixed.

Then the plate provided with the fixed image is placed again on the heated surface and heated until the image is completely removed. Then the plate is brought to room temperature cooled and treated according to Example II, a new image being obtained. From this it follows that a multiple use of the plate is easily possible.

Example VI

A coating solution is prepared containing about 1 g of a diphenyl oxide modified novolak (pale amber solid, average

Ches molecular weight 480, softening point 55 to 60 ⁰ C, specific weight 1.11 g / cm ³ ) dissolved in an acetone / toluene mixture in a ratio of 1: 1. About 0.25 g of 2,4,7-trinitrofluorenone are then added to this solution. This mixture is stirred until all components are completely dissolved and then applied as a coating to an aluminum plate by immersion. The layer thickness of the coating produced in this way is about 10 μm after drying. ίο

The coated plate is then corona discharged in the dark with a provided negative charge of about 150 volts and exposed according to Example I for 15 seconds. The plate is then developed by placing it on a plate held at about 45 ° C. This creates on the plate an image corresponding to the projected image, which is distinguished by its relief-like outlines and the It is characterized by the absence of a solid surface coating.

The plate is removed from the heated base immediately after development, and that Image is frozen by cooling.

B is ρ ie 1 VII _{2 $}

A clear film of polyethylene glycol terephthalate with the dimensions 0.08 mm χ 15.2 cm 50.8 cm is deposited on a surface by vapor deposition ^ saponify in vacuo with an aluminum coating. The product obtained shows a conductivity at Surface of about 500 ohms / Π and a light transmission of at least 65%. A coating from the materials in Example I is then applied to the aluminum-coated surface Charge transfer complex applied by means of an engraving roller. The layer thickness of the so produced Coating is about 15 μm after drying. This film is then treated in accordance with Example 1, an image being obtained which shows through Resolving power, good refractive properties and solid surface coating and produces sharp images when projected.

Example VIII

On clear polyethylene glycol terephthalate film according to Example VII with a thickness of 0.08 mm, a coating of a corresponding Charge transfer complex prepared in Example II applied by means of an engraving roller. the The thickness of the dry coating is about 10 μm. The coated surface the film so produced is then in the dark with a negative charge by means of a corona discharge charged, which at the same time the uncoated film surface with a positive charge provides. This film is then as in example I and 11 exposed and further treated. The image obtained in this way is distinguished by the same properties like the images obtained according to Examples I and II. It gives sharp images when projected.

Formed between the support and the coating of a phenol-aldehyde resin and a Lewis acid A further separate, photoconductive or inert layer can be arranged in the complex. The charge transfer complex other materials can be added to synergistically reinforce or otherwise modify its properties. The photoconductive materials used in the invention can, for example, by means of suitable Dyes are sensitized. They can also be used with other photoconductive materials and / or mixed with other organic or inorganic materials. Is the one with a deformation picture provided plate as in Examples VII and VIII is transparent, it is excellent for viewing suitable in projection devices.

In addition, the thermoplastic photoconductors produced according to the teaching of the invention can be used in the gravure or micro printing technology and in similar fields of application.

Claims (2)

Patent claims: 1. Electrophotographic process for the production of images, in which on an electrophotographic Recording material with a thermoplastic photoconductive layer has a charge image applied, the recording material is heated until a deformation image is formed and the deformation pattern is fixed by cooling, characterized in that that a recording material with a photoconductive layer is used as a photoconductor a charge transfer complex composed of an electron acceptor and an optionally contains modified phenol-aldehyde resin. 2. The method according to claim 1, characterized in that a recording material with a Charge transfer complex is used, which is a phenol-aldehyde resin of the formula