DE2115440A1 - Electrophotographic reproduction process - Google Patents

Description

Electrophotographic production process

The invention relates to an electrophotographic reproduction process, in which a uniform electrostatic charge is applied to the surface of a photoconductive recording medium applied and this is irradiated with a light-shadow pattern corresponding to the image to be reproduced.

It is already known to generate images on thermoplastic surfaces by creating reliefs by deforming these surfaces in an image-wise distribution. The image is generated by the formation of elevations and depressions av: £ of the thermoplastic surface. Light reflected on the deformed surface or transmitted through it can make the recorded image visible, since the light is scattered or refracted by the deformations. There are three different types of relief image generation on thermoplastic surfaces.

The first type of image generation is the so-called "matting process", that in U.S. Patents 3,196,009, 3,196,011, 3. '.!> »& 33o and 3 196 008. The matting picture production ;; ung has hitherto been carried out in such a way that a stress pattern is created on a thin, icoliorendcn, thermoplastic layer was generated. This tension pattern is usually associated with

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an adjacent layer of a photoconductive material, but the thermoplastic layer itself be photoconductive. The electric field is applied to the layer arrangement from thermoplastic and photoconductive layer · or produced on the photoconductive thermoplastic layer. The light intensity pattern on the photoconductive material acting image creates a variable electrostatic field,

It has been found that a thin, liquid layer on which a strong electric field is generated, is preferably deformed in a pattern that is precisely matched to the spatial frequency changes of this field when the changes primarily from spatial frequencies in the range of 1/2 T , where T is the thickness of the liquid layer. If the field pattern changes more slowly, wrinkles or random deformations are formed on the surface of the layer, which have characteristic spatial frequencies in the range of 1/2 T and are referred to as matting. The expression 1/2 T is often referred to as the resonance frequency of the deformable layer. Images with spatial frequencies within the range of the resonance frequency of the deformable surface are reproduced very well by such a deformation. Images with spatial frequencies that are lower than this resonance frequency produce matting in the areas of strong lighting. In connection with an optical Schlieren system or another suitable arrangement, images of good quality can be reconstructed from the matting deformations. However, the inherent noise of the matting image has a disadvantageous effect for some applications.

The second type of image generation is also called "grid matting" and is known from U.S. Patents 3,196,012 and 3,436,216. This mapping process enables Recording of deformation images with spatial frequencies much lower than the resonance frequency of the deformable Layer are. It would be shown that by a line absorption

rr.stor with a spatial frequency close to the resonance frequency of the dofornicrbcren area between the projected image the photoconductor and the photoconductor itself a deformation can be generated, which in the illuminated areas of the Photoconductor does not show any lating. The continuous parts of the image, i.e., areas with low spatial frequency are filled with I-Iattings ur.bc-i, but with remnants of the Rr.stcrs are available if they are not wanted, so : n by subsequent spatial filtering or by • c-known procedures are removed.

"The third type of image generation is a variant of the first two, but because of its density it is specially explained. It enables holograms to be recorded on a deformable layer a laminated assembly of oiner thermoplastic and a photoconductive layer Bosch rubbed. a hologram is a recording of the Interferenznuoters two light beams which are coherent to each other with-. IZlYi light beam usually contains information of an object, dor other is a reference beam with simple generally .The structure. the Interierenzmuster normally has the appearance of a somewhat mutilated image on an image carrier. When the spatial frequency of the image carrier approaches the resonance frequency of the thin, liquid layer, the surface deforms along the structure of the interference pattern and only a small amount of noise is generated.

All of the above-mentioned types of imaging work with deformation of a thin plastic layer caused by the action of heat or solvent vapors are softenable. They can be carried out repeatedly by applying heat or in principle Solvent vapors are brought into action to soften the plastic and the image recorded in each case is deleted. Usually the surface can then resolidify by cooling it or exposing it to a ventilator «, then another image can be created

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will. However, these procedures cannot be cycled very quickly. It also requires a cyclical Implementation of the expenditure of solvents or large input services. It has also been observed repeatedly that the engineering plastics cannot be completely extinguished, because chemical changes are connected with the development process. Therefore, only a limited number of these substances can be used Imaging cycles are performed. There is therefore the Need for an improved method of reproduction that repeats and can be carried out cyclically quickly and economically and causes a low power requirement.

The object of the invention is to provide a method of the type mentioned above which avoids the mentioned disadvantages of known methods and allows zyhlen a recording and erasure of information in many process. Furthermore, the recording of optical interference patterns with a high spatial frequency, for example holograms, and with a low spatial frequency should be possible. The respective recording should take place within a narrow range of liaural frequencies or within several narrow ranges of liaural frequencies.

To achieve this object, a method of the type mentioned at the outset is designed according to the invention in such a way that a recording medium with an electrically insulating, elastoneren layer is used and that the irradiation up to one deformation of these corresponding to the light-shadow pattern Shift is carried out.

A device for carrying out this method is shown in a further development of the inventive concept by a recording medium with a photoconductive Layer and a clastomeric layer applied thereon, by an arrangement for generating an electric field between the elastomeric and photoconductive layers and

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by means of a device for irradiating the photoconductive layer with a light-shadow pattern «

With the method according to the invention, it is possible to record images in cyclical repetition, to store them for a short time and, if desired, also to delete them. The recording medium used for this consists of a base which is electrically conductive or provided with an electrically conductive surface. A photoconductive layer is provided on this surface, the conductivity of which depends on the respective light intensity In another embodiment, a separate photoconductive layer can also be dispensed with if the elastomeric layer itself is also photoconductive. A thin, flexible metal layer, a flexible transparent conductive layer, a conductive liquid or a conductive gas can be applied to the surface of the elastomeric material. An electric field is then generated between this surface and the conductive substrate, so that in those areas v / o the photoconductive layer was irradiated with light, the electric field on the elastomeric layer is intensified so that it is correspondingly deformed. While maintaining this electrical field, the elastomeric layer remains deformed. This deformation is not significantly affected by the subsequent illumination of the photoconductor, so that it can be described as electrically blocked. The recorded image information can now be read out with any degree of brightness as required. The deformation is removed by removing the electric field, which releases the elastomeric material. By reversing the field on the elastomeric layer instead of removing the field, the image can be erased much more quickly. Then a new image can be created. It should be noted, however, that the property of electrical blocking of the elastomeric material occurs only above a certain value of the electrical field strength. Below this value the

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Image slowly erased. Therefore, the speed of image erasure can be controlled.

Since thin layers of elastomeric materials behave similarly to thin layers of viscous liquids with little deformation, an imaging assembly with an elastomeric material such as a thermoplastic imaging assembly can be used to generate three different images, namely shading images, screened matting images and images with limited However, because an elastomeric material is generally substantially incompressible and because the degree of its possible deformation is limited by internal elastic forces as well as surface forces, a thin elastomeric layer can respond well to a pattern of surface forces that occur within a The highest sensitivity is shown at the resonance frequency, which, as with thermoplastics, normally has a value of about 1/2 T. If an elastomeric material is exposed to an image, its If the main information lies within the narrow spatial frequency band of the elastomeric material, it records this image very well. Such images are of great use primarily for holography and for recording high contrast printed, written, or numerical information. When an elastomeric layer is exposed to an image composed of spatial frequencies below the recording tape of the elastomeric material, the highly illuminated areas of the material deform in a random, deformation pattern that corresponds exactly to the matting of the thermoplastic recording. The spatial frequency of the matting deformation is within the recording bandwidth of the elastomeric material, and the matting randomly scatters incident light. Areas that are less strongly illuminated are not matted and therefore do not show any scattering. Such an image is referred to as a matting image and, like thermoplastic images, sometimes also has disadvantages, since it has a certain noise structure.

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The third type of relief image generation, known as raster matting, is suitable for recording images with spatial frequencies below the deformation resonance frequency of the elastomeric layer. The image is generated with an absorption line grid between the projected light image and the photoconductor that is projected onto. The elastomeric material is deformed along the Huster this grid with high Raumfroquenz in those areas where it is illuminated, hence no Ilattierungen * to contact the image produced by the · Rasterr.attierung then consists of segments of the shielded by the master regions. That by lighting the elastomer ?! The image obtained from the material then has a fine line structure which is superimposed on the recorded original image. If this line structure is undesirable, it can be removed by suitable optical filter methods of a known type.

The invention with its further features and advantages is described below with reference to the figures. Show it:

Fig. 1 shows the section of a rildzeugungsanordnung with a elastonic material according to a first embodiment the invention,

FIG. 2 shows a second embodiment of the invention, FIG. 5 shows a third embodiment of the invention, Fig. 4 shows a fourth embodiment of the invention, 5 shows a multilayer arrangement with an elastomeric material according to a further embodiment of the invention and

Fir. 5 schematic representations of various physical up to 10 applications of the method according to the invention "

An "elastomeric material" is to be understood in the following to be an amorphous material which, upon deformation shows a restoring force. This means that the amorphous material is deformed under a force and as a result of volume and surface forces in its before deformation present shape returns.

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The embodiment of the invention shown in FIG. 1 is one Imaging assembly comprising an elastomeric material in which charges are applied to the surface of the elastomeric material with a Corona discharge device are applied. Corona discharge devices are known in the form of corotrons or scorotrons. With such a device v / ground positive or negative ions generated in a I-hole voltage field in a gas and applied to a surface.

The arrangement shown in Fig. 1 contains a base 1, which is either electrically conductive or provided with a conductive Schicirc. In general, a transparent backing is used, but it can also be opaque if this is due to the elastomeric !! Material reflected light is used to reconstruct an image. The base 1 can also be provided with a highly reflective mirror surface, so that the reconstruction light is guided through the elastomeric material, is reflected on it and passes through again (LY ₁ I . results in the double-c modulation, compared with a light-transmitting arrangement should the backing be transparent so IIL'SA-GLAC can be used diene is a nit Zinno;. cid coated glass on the corresponding one of the Scriicht 2 in Fig. 1 Side is electrically conductive. Furthermore, a transparent glass with a metallic, electrically conductive layer on soiiicr surface can be provided - which must be sufficiently transparent. If a light permeability of the base is not specified, a metallic base can also be used also consist of a plastic material, for example Mylar or acetate, if it is to be flexible, Menn the base 1 n layer is conductive, a layer 2 must be provided which is conductively ₀ This is normally formed of a transparent or partially transparent material.

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The photoconductive layer 3 is made of a material that allows an increase in an electric current in those areas that are exposed to light radiation. These The definition of a photoconductor can be extended to all substances for which the conductivity is light-dependent. A Such photoconductors often consist of a mixture of poly-n-vinyl carbazole with a sensitizing dye. The thickness of the photoconductor is between 0.1 micron and 200 microns what largely on the spatial frequency of the information to be recorded depended

The elastomeric layer 4 can be made of an elastomeric, soft one Solid consist, for example, of natural material such as natural rubber or synthetic polymers that are rubbery Have properties, i. they have to be elastic. Such substances are, for example, styrene-butadiene, polybutadiene, Ueoprene, butyl, polyisoprene, uritrile and ethylene propylene rubber cards. Preferably elastomeric substances, which must be used in the invention Methods applicable are gelatin gels based on water and silicon gels based on dimethylpolysiloxane. These substances can be used as a layer on the photoconductor in monomeric Form applied and polymerized on the photoconductor v / earth, or they v / earth as a layer of solutions in evaporable Solvents are applied, after which the solvents evaporate, leaving a thin, even layer. In general these substances should be very good insulators and specific ones Have volume resistance of more than 10 Ohm.

The thickness of the elastomeric layer is between about 0.1 microns and about 2000 microns, depending on the spatial frequency of the recording Information depends. Various optical properties of the arrangement can be improved by a suitable one Selection of the modulus of elasticity of the material is made. For example a stiffer elastomer will recover more quickly from a generated image when the electric field is removed is, i.e. it is erased more quickly. On the other hand, an 'atcri-

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experience and thus a stronger optical modulation for οinen enable specified field strength value,

The corona discharge device 5 can be a stationary pre ' direction if it applies a sufficiently even charge. It can also be provided in a scanning arrangement be. This arrangement applies positive or negative charges to the surface of the elastomer. The voltage drop on the layer arrangement of the elastomeric and photoconductive layer is in the range from 1 to 25,000 volts, which is based on the modulus of elasticity the elastomer and its thickness as well as certain properties of the photoconductor depends. Suitable scorotrons are for example, in U.S. Patents 2,836,725 and 2,777. The discharge device should be arranged in such a way that that they minimize the light acting on the photoconductor and the light used to reconstruct the image disturbs. The. The substrate 1 or the layer 2 of the arrangement shown in FIG. 1 do not have to be conductive in the case of corona charging because double-sided corona charging can be carried out to charge the surface of the layer 1 and the elastomer 4 for which purpose the two charging devices are each provided on one side of the image generating arrangement. They are fed with opposite polarities and on each other aligned past the assembly, so a second corona discharge device can meet the requirement Eliminate the electrical conductivity of layer 2 on the base.

During operation of the arrangement, the discharge device 5 applies charges to the elastomeric layer 4. The one shown in FIG The layer arrangement is then exposed to a light image which, when the substrate 1 is opaque, is produced from the right side will. If the base 1 is transparent, the light can be generated from the right or left. Document 1 or the Layer 2 are grounded so that an electric field is generated across the combination of photoconductive and elastomeric layers will. This electric field has a current of charge in them Areas of the photoconductor that are exposed to light

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are exposed so that the electrical F _R ld on the elastomeric layer is changed. The mechanical force of the electric field on the elastomer causes deformation. This deformation continues until the forces of the electric field are balanced by the surface tension and the elastic forces of the elastomer. At this point the deformation is interrupted and becomes stable as long as charges are applied to the surface of the elastomer which cause υ inc - maintenance of the electric field, further illumination with the picture _- is not required and the picture is in any way optical Stable. To delete this image, the field on the elastomeric !! Layer removed, the field on the elastomer can be reversed for faster erasure. The arrangement can now be used to accommodate a ^r .; Citeren formation.

In Fi ^ ₀ L a further embodiment of the invention; SSE ': i procedure shown in which an electric field cn Dorr. Elastomer 9 and the photoconductive layer 8 with a αϋηηοη, continuous and conductive layer 10 is produced on the ι ccri'lciche of the elastomer. This layer is so flexible that it follows the deformations of the elastomer. ^..: i. -R used a highly reflective layer 10, so <iivse arrangement utilizes the light used for ilekonstruktion with high "efficiency is the layer opaque, so that can be used from the left light generated to generate the deformation Mlcen , whereby the light generated from the right is used to reconstruct the image. The light sources can have different wavelengths or intensities. This arrangement can therefore be used to convert an image of one wavelength into an equivalent image of another wavelength The construction light generated here is much stronger than the light used for the image generation, the arrangement shown in FIG. 2 provides a high amplification of the input image; this amplified light can be used, for example, for large gout fields.

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As with the arrangement shown in FIG. 1, the base 6 can be transparent or opaque, depending on the intended use. The conductive layer 7 is optionally provided if the base 6 is not conductive. In the case of a transparent base 6, the conductive layer 7 should also be transparent * the photoconductive layer is provided over the conductive layer 7. On top of this lies the elastomeric layer 9. The thin, conductive layer 10 must be flexible enough to withstand the deformations of the elastomeric !! Layer 9 follows ₀ If the conductive layer 10 is opaque, a thin metal film, the base 6 and the conductive layer 7 must be transparent in order to ensure that the image information can act on the photoconductive layer 8. In this case, the image information can be read out continuously when the reconstruction light is generated from the right. If the conductive layer 10 is transparent, the light can be reflected on its surface, or the arrangement is used in a fluoroscopic method if the base 6 and / or the layer 7 are transparent.

The conductive layer 10 can be a thin layer of gold or indium, or it consists of a combination of the two Substances or other suitable metals. The thickness of the metal layers is normally about 50 or more Thousands of Angstrom units, depending on the flexibility and conductivity required. A transparent one and conductive layer 10 may also be used, for example made from Dow Corning's ECR 34 resin and is applied to the surface of the elastomeric layer 9. Other conductive layers, as they are known to the person skilled in the art, can can also be used in the method according to the invention. To create and block the deformation image, a Voltage applied between the base 6 and the conductive layer, which is approximately between 1 and 25000 volts, what depends on the thickness and the other properties of the elastomer 9 "

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A transparent insulating layer can optionally also be made over the conductive layer 10 of the arrangement shown in FIG oil may be provided. Your task is to make the manufacturing conditions for the imaging assembly less stringent to prescribe. The presence of pinholes in the elastonic layer 9 can cause a short circuit and possibly result in a reduction in the performance of the arrangement. Layer 12 causes short circuits and the consequences associated therewith prevents the insulating oil from flowing into such holes.

The voltage source 11 provided in FIG. 2 supplies a direct voltage predetermined polarity for generating and blocking a deformation image on the surface of the elastomeric layer, The polarity required depends on the type of photoconductor. The voltage source 11 must be switched off to erase the image its polarity must be reversible for faster erasure. For one TV picture, at yours per second Approx. 30 individual images are generated, saved and deleted, the voltage source must make such changes with the necessary Speed can perform. The degree of deformation and the speed of information erasure depend on the electrical values of the voltage source. The stability of the The voltage supplied must be so high that undesired erasure of the image is prevented.

In the embodiment shown in FIG. 3, a very thick, conductive liquid 16 is provided which is in contact with the elastomer 15 and enables the generation of the required electrical field on the elastomeric and the photoconductive layer. The other components of the arrangement shown in FIG. 3 correspond to those shown in FIGS. The base 12 can be transparent or opaque or conductive or non-conductive. The conductive layer 13 must be provided if the base 12 is not conductive. If the base 12 is transparent, the conductive layer 13 is normally also transparent. On the leitfähigert layer 13, the photoconductive layer 14 and the elastomeric layer PY are arranged.

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The thick, conductive liquid 16 in FIG. 3 can be transparent or be opaque. Opaque and conductive liquids are mercury, "g-o-melted at room temperature Gallium-Indium Alloys etc. Transparent Liquids' are water in which electrically conductive impurities are stored are "The liquid 16 should, if it is · transparent, have a different refractive index than the elastomer 15 in order to ensure that the deformations of the surface of the Elastomers phase modulate the incident light. A transparent liquid can also be used for reflection, this can be improved by applying a thin, flexible and transparent layer to the elastomer 15, in which these have a different refractive index compared to the elastomer or which has transparent and conductive liquid * A window layer 18 should consist of normal optical glass, which the conductive liquid on the elastomer2n Layer 15 holds. The voltage source 17 supplies the required operating voltage. It should be noted that most are conductive and transparent liquids in a DC voltage field undergo electrolysis. This is undesirable since it leads to a deterioration in the operating characteristics of the arrangement as well as leads to gas formation. The use of conductive and transparent liquids usually requires a Alternating voltage field on the arrangement of eltistomerer and photoconductive Layer"

The fourth embodiment of the invention is shown in FIG. This is essentially the same as that shown in FIG. 3, with the difference that the thick, conductive layer 16 is replaced by a conductive gas and thus an electrode 23 is required which, for example, can be designed as a transparent and conductive window. The conductive gas in the chamber 22, by a glow discharge in a gas at low pressure with a few millimeters of mercury can be obtained, or it is generated by an arc discharge under low pressure of a few microns of mercury "The Ga may -also highly radioactive materials in or near the gas or with

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Iloclifrequency excitation in chamber 22 or with other seducers, ionized to generate a conductive gas plasma will. The charging of the surface 21 of the elastomer can also be carried out when the gas is in a sufficient amount is in a high vacuum and contains a source of thermally excited electrons, for example a heated tungsten filament, whereby the electrons are directed onto the surface of the elastomer. You can also use an electron gun in the form of a scanning beam or an unscanned beam or with other suitable emission devices. : ^ A reflective layer can be on layer 21 or be provided between layers 21 and 22.

Apart from the conductive gas, the components of the arrangement shown in FIG. 1 agree with those of the arrangement according to FIG. 3. The base 16 has a conductive layer 19, it can be transparent or opaque. The photoconductive layer 20 and the elastomeric layer 21 are arranged on the insulating layer 19. However, the conductive gas can have a thickness of 0.1 microns to infinity. As already stated, the electrode 23 can be a separate electrode, or it can be connected to a transparent and conductive window which holds the conductive gas on the elastomeric layer 21. The chamber for the conductive gas must of course be hermetically sealed so that the gas is kept under the required vacuum.

l-.ir. the arrangement shown in Fig. 4 is a novel charge an area without the use of a corona charging device, for example a corotron or a scorotron, möj; liclir The kachteile of the corotron and the scorotron consist in that a relatively high power is required compared to the charge density applied to a layer. Furthermore, corotrons and scorotrons as corona discharge devices must normally be relative to the layer to be charged moves v / earth. For example, in xerographic machines an electrophotographic drum one coated with selenium

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Aluminum drum can be attached to a corona discharge device rotated past, whereby this relative movement is generated. When using one opposite the line of movement of the Corona discharge device flat surface to be charged, the discharge device must also experience an advancing movement. Since the known corona discharge devices in normal Working room atmosphere, which is always, a normal air different Contains moisture, has built up on a layer The last load does not always deliver the exact desired value Fig. 4 shown these disadvantages .jedoch by Avoid using the conductive gas in a predetermined vacuum, thereby reducing the amount of charge applied to a layer can always be precisely determined. If the conductive gas is connected to a vacuum pump, the negative pressure and / or the voltage applied to the electrode 23 can be adjusted so that the charge applied to the layer is always accurate is set.

Several modifications of the various elements in the above-described arrangements of the type shown in Figures 1-4 are possible. The elements or combinations of elements described below can be used instead of those explained above «

In the above-described photoconductive layers, in addition to the dye Brilliant Green manufactured by J.T. Baker Chemical Company, which added the poly-n-vin3aearbazole to sensitize it to red light, other dyes are used, for example trinitro-9-fluorene for Sensitization for blue light. Finely ground pisces toffo like phthalocyanine, foly-n-yitaylcarbazole added to a! sensitivity to visible light to create. Other known organic photoconductors can be advantageous be used. In addition, non-organic photoconductors, for example selenium and selenium alloys, can be provided These photoconductors are generally not transparent, so that their application is limited to those arrangements which

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do not require a transparent pad.

One photoconductive © and one elastomer. Layer can also by a single layer of a conductive elastomer be replaced under certain conditions. For example, an elastomer made from Sylgard 184 and dimethylpolysiloxane oils can be made photoconductive to blue or ultraviolet light by adding p-phenylenediamine, iodoform and the orange Calco Oil dye made by American Cyanamid Company, to be added before curing.

A thin elastomeric layer can undergo sufficient elastic deformation within a narrow spatial frequency band. The sensitivity outside of this range is quite limited. The spatial frequency sensitivity of the elastomer can be broadened or spiked by replacing the single elastomeric layer with multiple layers, as shown in FIG. Each of these layers 25, 26, 27 and 28 has a different limited sensitivity spectrum, but the spatial frequency spectrum of the combination is broad or multi-pointed. In general, the thickest layer 25 is closest to the photoconductor and the thinnest layer 28 is the has deformable surface. Two or more such layers can be used as desired. As already described, each of these layers can be photoconductive, so that a special photoconductor is not required and, in some cases, the resolution of the arrangement is improved.

It should also be pointed out that in addition to adjusting the thickness of the elastomeric layer to broaden its sensitivity with respect to the spatial frequency within a predetermined bandwidth, the modulus of elasticity can also be changed in order to produce deformations which are adapted to the bandwidth of the spatial frequency. Fabrics with a lower modulus of elasticity can produce larger elastic deformations _P On the other hand, fabrics with a higher modulus of elasticity become faster

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turned off. Such factors must be taken into account, if not an arrangement depending on the speed of operation or greater Deformation should be designed.

E is some of the embodiments described above reflection of light on the surface of the elastomer is possible » Numerous methods of improving such reflection are known. In addition, it has been shown that thin Layers of gold or indium and possibly of other metals due to Väküümäüfdampf on the surface of the elastomer can be applied in such a way that a highly reflective Results in surface that is sufficiently smooth to produce little optical noise. An examination of such However, Faces shows that they are made up of small islands of metal packed together in a very dense arrangement are ο Such a metal deposit does not only seem to change the elasticity behavior or the electrical insulation properties of the surface, but also improves the reflectivity the respective area.

It has been stated above that the elastomeric surfaces described can be used for recording, storing and deleting image information Can be used within a large number of cycles if the 'electrical fields on the elastomer are not too get strong. When these fields are so strong that the deformations of the elastomer exceed the elastic limit of the material, the image on the elastomer becomes permanent recorded. For many purposes this is undesirable, however, there are also cases where permanent recording is desired. The cyclical properties of the elastomer can can therefore be used to generate an image of sufficient quality, this image can then be overdriven by a voltage override be permanently fixed.

6 to 10 are physical applications of the invention Procedure shown. Fig. 6a shows a Arrangement for generating a matting image or a

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Uacternatierung rait an elastomer layer arrangement. A light source irradiates an object, the reflected light of which is focused on the carrier. The elastomeric surface records the image so on, as described for the FIG. 1 to embodiments shown, "The evaluation of the image takes place according to FIG. 6b _e the light source illuminates now the elastomeric surface of the multi-layer arrangement, the reflected light is not in the matted areas is generatedc The light incident in the matted areas is scattered. This scattered light reaches the lens and creates an image in the image plane. For this image, the padded areas appear light, the non-matt areas dark, so that a positive image results with light and dark areas that correspond to the areas of the same type in the original.

If the light source supplies coherent light, such as it is the case with a laser, the arrangement shown in FIG. 6 can also be used to record a hologram. The in Fig. 6a The light source shown can direct a reference beam onto the recording medium supply and, together with the light beam modulated by the object, creates a holographic one Image on the recording medium. When reconstructing a Luinliche light source used whose light on the multilayer Arrangement ger.äß Fig. 6b applies. There, however, the lens is not required to generate the reconstructed image.

. The arrangements shown in Figures 6a and Gh are in the · '■.? _C 1 adjusted to 4 shown embodiments of the invention "Ge ::: BB; In the embodiment shown in FIG. 2, the reconstruction light can be generated from the left or from the right, V-GiCi the conductive material 10 is transparent. If this layer IC is opaque, the reconstruction light must be drawn from the left. In this case, the image can also be evaluated at the same time as ι \ ζ -: \ Record. According to the embodiment shown in FIG. 3, the construction light can be generated from i -'-clLtr or from the left, when the liquid

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is transparent. If it is opaque, the evaluation light must be generated from the left.

Figo 7 shows a further arrangement, which according to "the invention Method operates similarly to that shown in FIG Arrangement, the light source acts on the object, whose reflected light is focused by the lens »According to the In the method shown in Figures 1 to 4, the image is recorded on the elastomer in the presence of an electric field. During reconstruction, the light source in the arrangement shown in FIG. 7 now illuminates the recorded image the elastomer. The reflected light is collected and imaged by the lens. Between the figure plane and the Lens is the focal point of the lens which, using a spatial filter in the image plane, creates a positive image or a Negative image creates «This means that a matted image reflects high spatial frequencies, while the non-matted ones Reflect areas with very low spatial frequencies. A spatial filter placed at the focal point of the lens filters the signals of low spatial frequencies, while the signals of high spatial frequencies are shown in the image plane as a positive image will. A ring-shaped spatial filter is used for a negative image, which filters the signals of high spatial frequency filters out while it lets the low frequency signals through. The arrangement shown in Fig. 7 can be used with the types of processes shown in Figs. 1 to 4, in addition the generation of a hologram is possible in the manner described.

FIG. 8 shows a further possible implementation of the method according to the invention, the image being recorded in a manner similar to that in FIG. 6a. During reconstruction, however, the light is allowed to pass through the elastomeric layer and is not reflected by it, as shown in FIGS. 6 and 7, B ¹ Ur a fositive image and the respective spatial filter is also required for a negative image. This embodiment corresponds

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The types of processes shown in FIGS. 1 to 4 such as the embodiments shown in FIGS. 6 and 7, The process shown in FIG. 2 can only be used when the conductive layer 10 is transparent. The method shown in FIG. 3 can only be used when the conductive liquid 1β is transparent ₀

An arrangement is shown in FIG. 9 which works according to the method according to the invention and in which the construction and reconstruction steps are carried out simultaneously with matching or different light sources. The light of an object, which is illuminated with light of a given wavelength and intensity, is focused on the photoconductor of the recording medium. At the same time, the light of a possibly different wavelength and / or intensity is reflected on the coated surface of the elastomer. Diosos DiId is converted into an intensity image in the image plane, as has already been described in connection with FIG. 6. The arrangement shown in FIG. 9 can also be used to form a hologram, as has already been described in connection with FIGS. 6 and 7. The illuminating light not only acts on the object to generate an object-modulated wavefront, but also irradiates the recording medium with a reference beam, thereby forming a hologram with the object wavefront and the reference wavefront on the surface of the Jlastor.icrs. The illuminating light f! UGlic muli · deliver coherent light, for example it has to be a LaGGi ". When the image is read out, a coherent light source acts on the other side of the recording medium, so that the light refracted at iJim generates the reconstructed image. This is natural Fig. 9 corresponds to the embodiment of the lens system shown in Fig. 2 for simultaneous image generation and image read-out, primarily when an opaque metal is used for the layer 10 or when the readout wave radiation is generated by radiation which does not activate the photoconductor, which means that the photoconductive layer

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of the recording medium can be insensitive to the readout light or that the readout light affects the generation of the south on the surface of the elastomer. If these conditions are not met, the arrangement shown in Fig. 9 is primarily adapted to the method shown in Fig. 2, wherein the image is first generated and then read out. The read-out light is not present with sufficient intensity during image generation to interfere with image generation. The arrangement shown in FIG. 9 is also adapted to the types of processes shown in FIGS. 1, 3 and 4, in which simultaneous image recording and image reading with spatial high-pass and low-pass filters is possible, which depends on the generation of a positive or negative image. It is assumed that the reading light does not activate the photoconductor.

Fig. 10 enables with the record carrier the one described Kind of a holographic record. In Fig. 10a a laser is shown which is directed to the object by reflection on a mirror acts while an undisturbed reference beam acts on the record carrier. The light beam modulated on the object ■ causes, together with the reference beam in the elastomeric layer, the creation of a holographic image, by omitting the Mirror and the object, the laser can reconstruct the image for a person in the illustrated in Fig. 10b Way to be used. Thus, Fig. 10 shows the recording of a holographic interference pattern instead of a focused one Image. The statements made in connection with FIG. 8 also apply here, however, in order to read out the image, the acting wavefront be coherent.

Methods and arrangements for image recording have been described above and image reproduction using elastomeric fabrics. With an elastomeric material, one results fully cyclically applicable recording medium, recorded on dom images depending on i / un, stored for a short time and can be deleted, ils were certain substances and arrangements described for the recording medium, however, os can

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also other, similar arrangements using a alc-octoneren material used v / erden, oline from the basic idea deviate from the invention. There are therefore numerous to the person skilled in the art ijiaorunger ·. inequitable embodiments of the invention :, K ;; licli. Bites are caused overall by the basic principle of Jr:. "Indung recorded.

109843/1640 ÖAO ORiQlNAl

Claims (38)

-24- 211544Q Claims M »j electrophotographic production process in which a uniform electrostatic charge is applied to the surface of a photoconductive recording medium and this is irradiated with a light-shadow pattern corresponding to the image to be reproduced, characterized in that a recording medium is provided with an electrically insulating, elastomeric layer (4) is used and that the irradiation is carried out up to a deformation of this layer (4) corresponding to the light-shadow pattern. 2. The method according to claim 1, characterized in that the polarity of the electrostatic charge for erasing the image is reversed on the elastomeric layer (4). 3. The method according to claim 1, characterized in that the electrostatic charge to erase the image on the elastomeric layer (4) is removed. 4. The method according to any one of claims 1 to 3, characterized in that that a recording medium with an elastomeric layer (4) on a photoconductive layer (3) on conductive Pad (2) is used and that the uniform electrostatic charge is generated with an electric field that exists between the elastomeric layer (4) and the conductive base (2). 5. The method according to claim 2, characterized in that the Steps of applying the electrostatic charge, the Irradiation and the polarity reversal are repeated several times, so that several deformation images appear one after the other the elastomeric layer (4) generated and deleted again. -25- 211544Q 6. The method according to any one of claims 1 Ms 5, characterized in that that the elastomeric layer (9). after applying "the electrostatic charge with a thin continuous and providing an electrically conductive layer (10) which is so flexible that it corresponds to that on the elastomeric layer (9) generated deformations follows, and that for reading out the generated image light on the deformed surface the elastomeric layer (9) is reflected. 7 · The method according to claim 6, characterized in that a transparent conductive base (7) is used and that the irradiation through this base (7) with information-modulated light and for reading out the generated image from the other side with unmodulated light Light occurs. ü. Method according to claim 7, characterized in that the on the elastomeric layer (9) generated image using non-modulated light with opposite to the information-modulated Light of different wavelengths is converted into an equivalent image. 9. The method according to claim 7 or 8, characterized in that the image generated on the elastomeric layer (9) by application an unmodulated light of higher intensity than the information-modulated light is amplified. 10. The method according to claim 4, characterized in that the surface of the elastomeric layer (15) with an electrically conductive liquid (16) is brought into contact and that the voltage source (17) for generating the electrical Field between the electrically conductive liquid (16) and the electrically conductive base (13) switched on will. 109843/1640 11. The method according to claim 4, characterized in that the surface of the elastomeric layer (21) with a brought electrically conductive gas (22) into contact and that the voltage source (24) for the electric field between the electrically conductive gas (22) and the electrically conductive pad (19) is switched on. 12. Recording media for image generation according to the method according to any one of claims 1 to 11, characterized in that that an elastomeric layer (4) with photoconductive properties is applied to a photoconductive layer (3) which is deformed when the photoconductive layer (3) in the presence of an electric field of light radiation is exposed. 13. Recording medium according to claim 12, characterized in that an electrically conductive layer support (2) is provided is. 14o recording medium according to claim 13, characterized in that that the electrically conductive base (2) is provided with a transparent carrier layer (1) and consists of a thin, metallic layer (2). ο Device for carrying out the method according to one of the Claims 1 to 11, characterized by a recording medium with a photoconductive layer (3) and a applied thereon elastomeric layer (4), by an arrangement (11) for generating an electric field between the elastomeric (4) and the photoconductive layer (3) and by a device for irradiating the photoconductive layer (3) with a light-shadow-luster. 16. Vorrichtimg according to claim 15, characterized in that several elastomeric layers (25, 26, 27) of different types Provide thick and different elasticity numbers are. 109843/1640 8AD OftlGWAL 17. Device according to Claim 15 or 16, characterized in that that an arrangement to interrupt the action of the electric field is provided, 15. Apparatus according to claim 15 or 16, characterized in that that an arrangement for reversing the polarity of the electric field is provided. 19. The device according to claim 15 or 16, characterized in that the elastomeric layer (4) has a predetermined modulus of elasticity which results in a deformation in pictorial distribution as well as its blocking when exposed to further light. 20. Apparatus according to claim 15 or 15, characterized by an arrangement for increasing the intensity of the electric field for permanent deformation of the elastomeric layer ('Y) in image-like distribution after exposure to radiation. 21. Device according to one of claims 15 to 20, characterized in that that a first light source is assigned to an object for -Jrzcugung an information-modulated light beam is acting on the photoconductive layer that a second light source of the deformed elastomer Layer is assigned and that a lens is provided which collects the light scattered on the elastomeric layer and creates an image in its image plane. 22. Device according to one of claims 15 to 20, characterized in that that a first light source for coherent light an object for generating an information-modulated Light beam and for generating a light beam acting directly on the elastomeric layer to form a Holograms are assigned on the elastomeric layer and that a second coherent light source of the deformed elastomer Layer is assigned whose light scattered on the elastomeric layer is a reconstructed holographic Image generated j *: 109843/1640 23. The device according to claim 21, characterized in that a spatial filter between the lens and the image plane is arranged that a positive image when filtering low spatial frequencies, when filtering higher spatial frequencies Frequencies creates a negative image in the image plane. 24. Device according to one of claims 15 to 20, characterized in that that an object is assigned a first light source for generating an information-modulated light beam is on one side of the elastomer !! Layer is directed and that a second light source at the same time the other side of the elastomer !! Shift is assigned and reconstructs the recorded image. 25. The device according to claim 24, characterized in that the elastomeric layer is associated with a lens which focussed part of the reflected light from the second light source in its image plane. 26. The device according to claim 24, characterized in that the first light source generates coherent light and likewise acts directly on the elastomeric layer to create a holographic image on the elastomeric layer and that the second light source generates coherent light which, when scattered on the elastomeric layer, reconstructs the holographic image supplies. 27. The method according to any one of claims 1 to 11, characterized in that the electrostatic charge by! ". Crilhrung the layer to be charged with an electrical Io iti ^v: '.hi, ;; ... /. Gas and by generating a electrical l / eldes:; \ 'ir, 0Acn the electrically conductive gas and which is generated to Inder o.on »jcl-icht. SAD OWQINAL, 1098A3 / 1B4G 28. The method according to claim 27, characterized in that the electrically conductive gas is kept under a precisely specified vacuum, whereby a specified amount of charge forms on the layer to be charged. 29ο Method according to claim 27 or 23, characterized in that that the contact of the electrically conductive gas with the layer to be charged by a glow discharge in a gas takes place at low pressure. 3ü. Method according to claim 27 or 28, characterized in that that the contact of the layer to be charged with the electrically conductive gas by ionization of a gas with low ■ Pressure is carried out by means of olfactory stimulation. 31. The method according to claim 27 or 23, characterized in that that the contact of the layer to be charged with the electrically conductive gas by ionization of a gas with little Printing with strong radioactivity takes place. 252. The method according to claim 27 or 28, characterized in that that the contact of the layer to be charged with the electrically conductive gas by an arc discharge in a gas under low pressure, 33. The method according to claim 27 or 28, characterized in that the contact of the layer to be charged with the electrically conductive gas by introducing a source of thermally excited electrons into a gas under high vacuum. 34. Device for performing the method according to one of the Claims 27 to 33, characterized in that an arrangement for contacting the layer to be charged with a electrically conductive gas and an arrangement for generating it an electric field is provided between the electrically conductive Ga a and the layer to be charged. 109843/1640 35. Apparatus according to claim 34, characterized in that the layer to be loaded with a chamber for receiving the electrically conductive gas is provided. Device according to claim 35, characterized in that the chamber is provided with an electrode (23) which generates the electric field in the electrically conductive gas, 37. Apparatus according to claim 35, characterized in that the chamber is electrically conductive. 38. Device according to one of claims 35 to 37, characterized in that - that the chamber is provided with a vacuum pump, which allows a precise setting of a predetermined negative pressure in the chamber and thus enables the transfer of a predetermined amount of charge to the layer to be charged. BAD Qft & tNAL 109843 / 16A0 Blank page