DE1522745A1 - Electrophoretic imaging process - Google Patents

Description

Patent attorneys Dipl. Inn-F. V \: c-ηαιη, Or. In _:. A. Wßid; - ^ nn 1522745 Di ·, .-! ': "* - * i." - V. "-: c; f ^ r.n, Di.'i. Phye, Dr.K. Fiiicke

'"'" 3 Manihan 27, Möhlstrasse 22

XEROX CORPORATION

Rochester, New York 14603 USA

The invention "relates, to an imaging method, in particular to an improved electrophoretic imaging process. /

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It has already become an electrophoretic imaging process designed with which it is possible to use colored images to produce electrically photosensitive particles. This process is largely in the German patent application X 37 IXa / 57 described.

In such an imaging method, different colored light absorbing particles suspended in a non-conductive carrier liquid. The suspension is between

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brought two electrodes, an electrical potential difference exposed and exposed to an image. Do Carrying out these steps, a selective rope migration takes place in a pictorial configuration, whereby produces a visible image on one or both electrodes will. An essential part of this process are the suspended particles, which are electrically photosensitive must be and which apparently have the polarity of their own charge when exposed to an activating electromagnetic steel by interaction with change one of the electrodes. A single color process uses particles of a single color, the a monochrome picture corresponding to the conventional black and white photo generate graphics. In a multi-colored process, the images are created in natural colors, since Mixtures of particles of two or more different colors which are only used for light of a special wave / ■ length or a narrow wavelength band sensitive are to be used. The particles used for this must have an intense and pure color and be very light-sensitive

After exposure and particle migration the electrodes are separated from each other so that the carrier liquid can evaporate. This means staying on one or both electrodes return images consisting of selectively deposited particles. The carrier liquid can a small amount of a wax or other binder included, which is necessary for the mutual bonding of the partial

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serve each other. However, it will be more than just a minor If a proportion of binder is used, this has an undesirable effect on the imaging process the end. Therefore, the images are in sensitive and sensitive areas easy to destroy condition. It was suggested to place a transparent sheet over the pictures, or to spray the pictures with a clear binding resin, -um to create a protective coating. With careful When this coating is carried out, the image is protected, but often it is during the application of this slit fabric damaged. This method cannot therefore be used for a fully mechanized device. There is also the risk of a Pollution or other impairment of an unfixed If you want to transfer the image from the electrode to an image sheet, please do so very well. Hence there is still the need for a better method for fixing the particle image on the electrode surface and / or for image transfer onto an image sheet.

Therefore, the object of the invention is primarily to a method of fixing an electrophoresis To find particle image that avoids the disadvantages listed above.

Furthermore, this method is intended to protect an electrophoretic image from damage.

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The method should make it possible to produce an electrophoretically.es Transferring an image from an electrode to an image sheet.

The images produced with this process should be used without fear of damage.

The invention is also intended to provide a method of production electrophoretic images can be found, which can be carried out continuously and in which the images against Wear and tear protected.

The foregoing and other features are in accordance with the invention by. Application of a heat-sticking (thermoadhesive) layer, which in a softened state on contact with an electrophoretic particle image an embedding of the particles and their permanent bond made possible upon re-hardening. This thermoadhesive layer can be applied as a coating on the electrode, on which an image is to be created. After the image has been created, the thermoadhesive layer is softened and the image becomes pressed against the layer, causing the particles to be embedded in it will. When this layer hardens again, they are Particles are permanently bound in it and thus protected against damage protected from contact with other particles. on the other hand the thermoadhesive layer can also be applied to a picture sheet as Coating are applied. After training an electrophoretic Image on an electrode, the image sheet is heated,

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to soften the thermoadhesive layer, and then with brought into contact with the image. The softened layer pulls the particle image off the electrode and forms when it hardens they provide a protective surface for the picture.

The advantages of the improved electrophoretic imaging process can be seen and an arrangement for its implementation are based on the following detailed description of the invention Hand of the figures.

Show it:

1 shows the side view of a simple embodiment an arrangement for carrying out the method according to the invention, in which a coating of a thermoadhesive image fixing layer is used on the image electrode,

Fig.2 shows a simple example image sheet that is used for Takeover of an electrophoretic particle image from a Image electrode is used, and

Fig. 3 shows a complete device for the production, Transfer and fixation of electrophoretic particle images.

In Figure 1, a transparent electrode 1 is shown, which

in this embodiment from one layer optically to

ο transparent glass 2 is made with a thin optically to

* transparent layer J is coated with tin oxide. This > ^ Material is available under the name NESA glass. The-

Our electrode is hereinafter referred to as the "injecting electrode" co

^ or "beam electrode". On this electrode 1 is a layer of thermoadhesive material 13 is applied, the

as a cover on a cellophane layer (not shown) located, and the "when heated by an infrared Lamp 14 becomes sticky.

Over this solidified thermoadhesive layer 13 is applied a thin layer 4 of finely divided light-sensitive particles which are dispersed in a non-conductive carrier liquid. The term "photosensitive" as used herein refers to the properties of a particle which, when on the injecting electrode, migrates away from that electrode under the influence of an electric field and exposure to activating electromagnetic radiation. A detailed theoretical explanation of the mechanism of these processes can be found in the above-mentioned German patent application X 3? M ** - _t to which the present description also relates. Adjacent to the liquid suspension 4 there is a second electrode 5, which is referred to below as the "blocking electrode ¹¹ " and which is connected to one pole of a voltage source 6 via a switch 7. The other pole of the voltage source 6 is connected to the injecting electrode 1 so that when the switch is closed between the electrodes 1 and 5, an electrical pressure is generated on the liquid suspension 4 and the thermoadhesive layer 13. An image projector consisting of a source of light 8, a transparent image 9 and an objective 10 is used to expose the Dispersion 4 with a photo of the transparent original to be reproduced

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"Fig. 9. The electrode 5 has the shape of a roller that is provided with a conductive core 11 to which the Voltage source 6 is connected. The core is with coated with a layer of barrier electrode material 12, which can consist of baryta paper ". The particle suspension is exposed to the image to be reproduced "while generated by closing the switch 7 between the barrier electrode and the injecting electrode, a potential difference will. The roller 5 is over the O "surface of the injecting Electrode 1 guided while switch 7 ″ is closed when the image is exposed. By this exposure are sigment particles that settle on the electrode 1 are located and exposed to migrate through the liquid until they are on the surface of the Blocking electrode. On the surface of the thermoadhesive Layer 15 left a pigment image that was the same as the original image 9 corresponds. The one on the face of the barrier electrode The adhered particles can be removed from this electrode by cleaning and the exposure steps can be performed therefore be repeated. Through this additional exposure and Cleaning the barrier electrode improves the color purity and balance of the image. Each exposure evaporates the relatively volatile carrier liquid, leaving behind a pigment image. To this At this point, the pigment image is very sensitive to Damage caused by contact with any objects, since it consists only of loosely bound particles .. That The image can be fixed by heating the thermoadhesive layer 15 by means of the infrared lamp 14. By the heating

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the thermoadhesive layer becomes gravelly, as described below and causes the particles to become embedded. The thermoadhesive layer can then harden again, after which it is removed from the injecting electrode and can be handled without contamination or other damage.

In another embodiment of the invention Method, the pigment suspension 4 can be applied directly to the NESA glass surface 13, with the intermediate thermoadhesive layer 13 is dispensed with. After completing the image construction described above, you will find on a particle image of the NESA glass surface. This can then on. a picture sheet, as shown in Pig.2, transferred will. Such a picture sheet consists of an underlayer 15, for example made of paper, cellophane or other suitable ones Fabrics. On top of this underlayer is a layer of thermo- ' adhesive 16 applied to that described above Layer 13 corresponds. The heating of this layer can turn Contact heat or infrared radiation. Then this layer with the particle image on the Electrode 1 brought into contact. On the other hand, the solidified thermoadhesive layer can come into contact with the particle image brought and then heated. In both cases will be the particles: embedded in the thermoadhesive layer and fixed in it as image 17 when the layer is again hardened. The image sheet is then removed from the injecting electrode and can be used in a conventional manner. ■ "- ■■■" - ■

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Fig »? shows an embodiment of a device for the continuous production of a photoelectrophoretic image, in which the image is transferred to a sheet and fixed thereon. The electrodes used in it are the same as those already written for]? Ig ,, 1. In the device shown, however, a transport device 18 is connected to the locking electrode 5, which automatically transfers and fixes the easitive image produced on the NESA glass surface the picture surface carries. The transfer devices consist of a continuous band 20 made of an image transfer material, e.g. paper, to which a thermoadhesive layer is applied 2% led. The hot guide roller 22 is provided with a heating device, which heats the thermoadhäsi veSchicht on its transition over this EaIXe over its softening stone temperature. a tube for feeding Damtpff in the inside of the roll, an electrical resistance heater,., or: an EeXtier heating element.t are used which are connected to the power supply die- theirmoadhäsive; · Layer under their Ervieichungstempeiater / aÄeXt * if, it is passed over this role * The EühXmittel, indicated schematically at. 26 _r can. in. conventional way to—

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be turned, for example by supplying water, or by using a Peltier cooling element that is connected to the power supply. A three-substance mixture 4 is applied to the transparent electrode 1. This is exposed to an image and the transport device is moved with the blocking electrode from left to right over the image area. In the process, unwanted particles migrate to the barrier electrode surface and leave a positive particle image on the NBSA glass surface 3. When the transport device reaches the IIESA space, the belt 20 touches the HESA surface 3 without mutual movement. The thermoadhesive surface on the belt 20 is heated over the roller 22. The partial image is in the softened area. the thermoadhesive layer. embedded. The thermoadhesive layer is then hardened again by the roller 23 and wound onto the take-up roller 24. Reaches the transport device with the barrier electrode, the end of its transport path, so 27 cleans the brush, the barrier electrode surface 5 of the undesired particles * The transporting device is then lifted slightly, and in its initial position _r returned without the transparent electrode to again touch. The gestriehtelte line 28 shows the case schematiseh traversed by the axis 29 of the roller electrode during the Eildherstellungiind Zuriickfuhrung Wegv As zui recognize _r ltann made with the device described in one operation a photoelectrophoretic image, transferred, fixed and stored.

The thermoaxüiäsiven layers 13 and 16 can be made of any suitable materials. The only requirements are that they be solid at room temperature are soft and with a reasonable increase in temperature get sticky. Shall ax directly on the injecting layer Electrode are applied, it is additionally required that it has conductive properties. Will the thermoadhesive Layer applied to the barrier electrode surface, as described in Example II below, this should

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Layer have a resistance between 10 and 10 ohm cm. The thermoadhesive layer preferably consists of a binding agent and a heat-effective earthening solvent. The latter consists of a substance that is solid at room temperature and "with a slight increase in Temperature melts. This creates the binder layer sticky and enables the particles brought into contact with it to be embedded. Should the created image through Projection are made visible, the thermoadhesive layer must be transparent «

Any suitable mixture can be used for the process according to the invention a binary hair and a thermal solvent are used will. Optimal results have been achieved with blends of Vinylite YYIfS, a vinyl chloride-vinyl acetate copolymer from Union Carbide Corporation, with Santolite MHP, an arylsulfonaHid-formaldehyde copolymer from Pa. Monsanto, of polyvinylpyrrolidone-yinylacetate copolymer with Santolite

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MHP, and from Vinylite VYHO with Aroclor 4465, a mixture chlorinated diphenyls with chlorinated triphenyls. Furthermore, the best results were achieved with the then also preferred used mixture of 1 part by weight of EXON-470, a vinyl chloride-vinyl acetate copolymer the PA. Firestone, with 1 part Santiziser 1-H, a sulfanamide resin from Pa. Monsanto, -

pre-dissolves acetone in 10 parts. This mixture is preferably with a thickness of approx. 0.013 now applied and dried. It however, other mixtures of a binder resin with a thermal solvent can also be used. Typical binding resins are ' Polyethylene, polystyrene, copolymers of vinyl chloride and vinyl acetate, Copolymers of vinyl pyrrolidone Tsmd vinyl acetate, poly viny! methacrylate, polyvinyl propylene, polyvinyl chloride, cellulose acetate, Chlorinated rubber and mixtures as well as copolymers of these substances. Typical thermal solvents, indicated with in brackets Melting points slightly above room temperature are: triphenyl phosphate (48 ° C), dicyclohexyl phthalate (63 ° C), Diphenylphthalät (69 ° C), Aroclor 5442 (46-52 ° C, chlorinated Polyphenyl of Pa. Monsanto), Santiziser 3 (58 ° C, N-ethyl-p-toluenesulfonamide the PA. Monsanto), Santolite MHP (62 ° C, sulfonamide-formaldehyde resin the PA. Monsanto), Santiziser 1-H (82 ° C, IT-cyclohexyl-p-toluenesulfonamide from Pa. Monsanto), azenaphthene (94 ° C), azetanilide (113 ° C), o-azetoazeto-toluidide (105 ° C); o-acetotoluidide (101 ° C), o-chloroazetoazetanilide (105 ° C), 2-chloro-4-nitroaniline (106 ° C), p-dibromobenzene (87 ° C), p, p'-methylenedianiline (93 ° C), Alpha-Naj) hthol (95 ° C), Beta-Naphthol (85 ° C), 2-naphthylamine (110 ° C), m-nitroaniline (112 ° C), 4-nitrodipheriyl (97 ° C), sorbitol hexoacetate (98 ° C), 2,4-toluenediamine (97 ° C), and mixtures of these substances.

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The ratio of binder to thermal solvent is chosen accordingly. Ratios of 0.5 "to 4 parts of binder resin for each part of solvent can be used. Best results are achieved with a ratio of 1 s 1, ^ ie ^ it may vary slightly depending on the particular substances used. The thickness of the thermoadhesive layer sQjll are preferably between 0.003 and Ο, Ί mm. The best balance in terms of good image transfer and economy is achieved with a layer thickness of approx. 0.013 mm. _:,,

The present invention is illustrated by the following examples with regard to the use of thermoadhesives Layers for fixing and / or transferring electrophoresis Pictures explained further. The specified proportions and percentages Unless otherwise stated, values refer to on weight. The examples contain descriptions of various preferred exemplary embodiments of the invention Image fixing and transferring method.

All examples I to I? are carried out with an arrangement as shown in Ex.1. In the various examples, however, the thermoadhesive layer is applied to the NESA-G glass surface, the blocking electrode surface, or applied to a special picture sheet (Fig.2). The NESA glass surface is with a switch, a voltage source and the conductive one Core of a roll with a baryta paper cover connected in series. The roll has a diameter of approx. 6.5 cm and comes with

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INSPECTED

4f

a speed of about 1.45 cm / sec over the plate surface. The plate has a size of about 7.5 cm × 7.5 cm and is measured with an illuminance of 86 4GO Lux, 'aif- the uncoated UESA glass surface, exposed. Unless otherwise stated, 7 percent by weight of the pigments listed in each example are suspended in Sohio Odorless Solvent, a petroleum fraction from Standard Oil of Ohio, and the voltage applied is 2500 volts. The exposure is carried out with a lamp of 320O ⁰ K through a colored "Kodachrom" slide

Example I.

Equal parts by weight of Vinylite VYNS, a vinyl chloride-vinyl acetate copolymer from Union Garbide Corporation, and Santolite MHP, an arylsulfonamide-formaldehyde copolymer from Pa. Monsanto are mixed in an acetone solvent and applied to a cellophane film to a thickness of approximately 10 microns, which is then applied to the IiESA glass surface. A three-substance mixture consisting of the cyan pigment Monolite Past Blue GS (alpha-Porm metal-free phthalocyanine, CJ. ¥ r. 74 100, available from Arnold Hoffmann Co.), from the fuchsin-colored pigment Vulcan Past Red BBE Toner 35-2201 I 3 , 3 ^l -dimethoxy-4-4'-diphenyl-bis (1 »-phenyl-3" -methyl-4 "-azo-2" -pyrazoline-5 "-one), CJ. ITr. 21 200, available from Collway Colors Company), and the yellow pigment Indofast Yellow Toner (Plavanthron, CJ. Hr. "70 600, available from Harmon Colors Company) is dispersed in about 100 parts of Sohio Odorless Solvent 3440 and applied to the with the

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INSPECTED

thermoadhäslven fabric covered cellophane layer on the NESA glass surface applied. A voltage is applied to the suspension and an image is created in the manner described above manufactured. The carrier liquid is then evaporated and the coated cellophane is heated with an infrared lamp until

the thermoadhesive material becomes soft. One role with one Fluorocarbon surface is thermoadhesive Layer rolled to press the particle image into it. Then the heating is interrupted and the thermoadhesive Layer can harden again. An excellent image is obtained with a hard surface that is resistant to abrasion.

Example II

Equal proportions of a yinylpyrrolidoh-vinyl acetate copolymer and from Santolite KHP are mixed in an acetone solvent. The solution is applied to a barrier electrode surface made of baryta paper with a thickness of approximately 10 microns and then dried or hardened. A three-part mishap The following pigments are used: Cyan pigment Cyan Blue GTSF, the beta form of copper phthaloeyanine, G.J. Mr. 74-160 available from CoIIw ^ Colors Company; fuchsin pigment Quindo Magenta RV-6803, a binacridone pigment from Harmon Colors Co., and yellow pigment Algol Yellow GC, 1,2,5,6-di (C, C'-diphenyl) -thiazole-anthraquinone, CJ. SFr. 67,300, available from General Dyestuffs Co. This three-component blend comes in approximately 100 parts of Sohio Odorless Solvent 3440 formed. It is placed on the HESA glass surface is applied, and a BjId is produced as in example

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The barrier electrode is cleaned of unwanted pigment particles and then heated until it becomes sticky. Then it will be the roll is guided over the ItfESA surface and takes the image particles and embeds them. The thermoadhesive layer can then harden again. The baryta paper with the pigment containing thermoadhesive layer is of the Role accepted and checked. It is an excellent picture • Quality with a hard, abrasion-resistant Surface available.

Example III

Equal proportions of Vinylite VYHS and Aroclor 4465, a mixture of chlorinated diphenyls and chlorinated triphenyls available from Monsanto, are dissolved in acetone and this solution is applied to a sheet of paper to a thickness of about 5 microns. A three-component mixture as in Example II is prepared and applied to the NESA glass surface. Then, an image is formed as in Example I. The sheet with the thermoadhesive layer is heated by placing it on a plate of SO ^0C. Once the sticky state has been reached, the layer is removed from the heating plate and pressed onto the particle image on the FESA surface. After removing the sheet and hardening the thermoadhesive material, an excellent image with a hard, abrasion-resistant surface has been created. '

Example IV

Equal proportions of EXON 470 and Santiziser 1-H are used in Acetone and this solution is drawn on a long paper

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tape applied and dried. The tape is wound onto a roll and inserted into an arrangement such as it is shown in FIG. To the IESA-G-Ia s el eMr ο de .will a three-component mixture prepared according to Example I. applied. An image is produced as in Example I. Unwanted pigment particles migrate to the barrier electrode and are removed with it, whereby on a particle image remains behind the NESA surface. When the transport device passes over the liESA plate, the particle image in the heated thermoadhesive surface depressed. If the paper tape is fed in front of the cooled roll, the thermoacbäsive material hardens, and so does it the result is a hard image surface that is on the take-up reel can be wound up. The imaging steps can then be repeated without delay.

Although specific compositions and amounts in the above Description of preferred exemplary embodiments of the thermoadhesive If a layer has been used, other suitable substances as listed above can also be used, with similar results be used. Other substances can also be added to the mixtures in order to adapt their properties to the to adapt and improve other components of the process or otherwise change it. For example, can be used for lightening of the picture added bleaching agent to the thermoadhesive material especially when a cheap type of paper is used to transfer images. Is the thermoadhesive Layer on the injecting electrode; so can

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ORIGINAL WSFECTED

Additives to increase the conductivity of this layer be used.

Further changes and modifications to the present invention will be apparent to those skilled in the art after knowing the foregoing Description possible without departing from the scope of the inventive concept.

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Claims (17)

I DZZ / patent claims 1.! A method for fixing a 'particle image, characterized in that an image is produced on an image surface (1) and that this image is in contact with a heat-softening thermoadhesive layer (13) is brought and embedded in this, after which the therinoadhesive layer (13) again in its non-adhesive Condition brought approx. 2. The method according to claim 1, characterized in that as Image area the area of the thermoadhesive layer (13) is used. 3 · "Method according to spoke. 1, characterized in that the thermoadJhäsive layer (16) with the particle image on the Image area (1) is brought into contact after the image has been produced. 4. The method according to claim 3> characterized in that the thermoadhesive layer (16) during their contact with the Image area (i) is heated. 5. The method according to any one of claims 1 to 4 »characterized in that that the thermoadhesive layer (13> 16) from a binding agent and from a binding agent for this when exposed to heat solvent Confesses. - 20 909842/1387 6. The method according to claim 5, characterized in that the Ratio of solubility. to binders between 0.5 and 4 lies. ■ 7. The method according to any one of claims 1 to 6, characterized in that that the thermoadhesive layer (13, 16) has a thickness of 0.003 to 0.1 mm. 8. The method according to any one of claims 1 to 7, characterized in that that the thermoadhesive layer (16) on its side opposite the image contact side with a base (.15) is provided. 9 · Process for the electrophoretic production of images and their fixation according to the method according to claim 1, characterized in that characterized in that a layer consisting of a pigment suspension (4) is between an electric field at least two electrodes (1,5) is exposed, of which at least one (5) works as a blocking electrode that simultaneously the suspension (4) is exposed to an image of activating electromagnetic radiation, whereby on at least one of the electrodes (1,5) after migration pigment particles form a pigmentary image • Will. That a heated thermoadhesive layer (16) with the Pigmentsotffbild is brought into contact and the particles embedded in itself, and that the thermoadhesive layer (16) then returned to its non-adhesive state. 9 842/1387 - 21 - I DLLI H - 21 - 10. The method according to claim 9, characterized in that the. thermoadhesive layer 4ls coating on the barrier electrode (5) is applied. 11. Veriäiren according to claim 9, characterized in that the thermoadhesive layer (13) applied to the electrode (1) which does not serve as a blocking electrode (5). 12. The method according to claim 9, characterized in that the thermoadhesive layer -. (. 1-6, Fig.2) on a base (15) which is not used as an electrode. 13. Device for carrying out the method according to one of Claims 1 to 12, characterized by a device (1,5) for producing a particle image on an image surface (-1) and by means of a device (18) for making contact of the particle image with a soft thermoadhesive layer (21) due to the action of heat, whereby the particle image in this is embedded. 14. Device according to claim 13 »characterized by a smooth, optically transparent first electrode (2), on one side of which there is a layer of an image solution (4), by a second electrode (5) for contacting the image solution (4), by a device (6,7) for generation an electrical voltage on the two electrodes (2,5), through a device (8,9,10) for the action the voltage simultaneous exposure of the imaging solution (4) with an image activating electromagnetic 909842/1387 ORIGINAL INSPECTED22 - / 4b - 22 - Radiation through the first electrode (2), whereby an image is created on at least one of the electrodes (2, 5) after image material particle migration, by means of an image under the action of heat sticky layer (20), by means (22,25) for heating this layer (20), and by means (18) for contacting the tacky layer (20) with the particle image, causing the particles therein Layer (20) are embedded. 15. Device according to claim 14, characterized in that the layer (13), sticky when exposed to heat, deip & rust Electrode (2) is located. 16. Device according to claim 14, characterized in that the see / heat sticky layer (13) on the second Electrode (5) is located. 17. Device according to claim 14 »characterized in that the layer (16) sticky when exposed to heat on a base (15) that is not used as an electrode. . Device according to one of claims 14 to 17, characterized in that that a device is provided for pressing the tacky layer (13, 16) against the particle image. 0 9 8 4 2/1387 ORIGINAL INSPECTED Blank page