DE2529893A1 - PROCESS FOR THE MANUFACTURING OF MATRICES FOR THE PRODUCTION OF COLORED REPRODUCTIONS AND THE PRODUCTS THEREOF - Google Patents

Description

22 266 - BR

SUBLISTATIC HOLDING SA

Playground 3

8750 Glaris / Switzerland

Process for the production of matrices for the production of colored reproductions and those obtained thereby

Products

The invention relates to a method for the production of matrices for the production of colored copies and the products obtained thereby; it relates in particular to a method for color reproduction electrostatic and thermal path. The invention also relates to the production of for the implementation of Intermediate copies suitable for the process, these intermediate copies or matrices and their production.

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The method according to the invention consists in that the image to be reproduced is thermally transferred from a matrix (on which it has been generated as an intermediate by electrostatic means) to a receiver, generally a plastic film or a sheet of paper, which is included is coated with a material that has an affinity for the dyes of the image. This transfer can easily be accomplished by heating the stencil in contact with the receiving sheet. Heating to temperatures above 14O ° C, even preferably above 170 ⁰ C, is essential if one wants to create transmission conditions that are sufficiently fast to be able to make multiple copies per minute.

To produce the intermediate copies used as matrices in the process according to the invention, the latent images corresponding to the color separations of an original are transferred successively and electrostatically from the photoconductive layer on which they are produced one after the other to a dielectric paper on which they are superimposed , develops each of the latent images transferred in this way before the transfer of the following one with the aid of a dry or liquid developer which contains a dye which can change into the vapor state between 120 and 220 ⁰ C and corresponds to the original color separation of the image to be developed, and fixed ^ e ^ oh ^ y ^ r.- if after each development that on the dielectric

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Surface generated image.

The formation of a latent image on the photoconductive layer can be carried out by known methods, for example by applying charges by means of metallic tips with a sufficiently high pulse voltage or after other methods commonly used in electrophotography, in which the image is formed by selective discharge of the previously on a photoconductive material (e.g. selenium, polyvinyl carbazole and the like) applied electric charges under the action has been generated by light. The latent image formed in this way can be deposited on the photoconductive material self-developed, but in the method according to the invention it is first applied to a dielectric surface transfer.

The electrostatic transfer of latent images from a photoconductive layer to a dielectric surface can be carried out by methods known per se. In this way, starting from a photoconductive Layer, which is located on an electrically conductive support, the electrostatic charges of a latent Transferring the image onto a dielectric layer applied to an electrically conductive substrate by the brings both layers into intimate or virtual contact with one another and then separates them from one another. The layers that are in contact with one another can also be

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to the action of an external electric field, which can be generated by a direct voltage or an alternating voltage or by a corona discharge. Depending on the method used, there is a thin layer of air between the two layers, which is precisely set to a value of 50 to 200 / a or the layers are in virtual contact with each other or an intimate contact is created between the two layers by applying a high mechanical pressure.

A virtual contact between the two surfaces is to be understood here as the fact that they lie on top of one another without a perpendicular external pressure is exerted on these surfaces. Between the two surfaces that are in virtual contact stand together, there is always a thin layer of air, the thickness of which depends on the smoothness of the two surfaces depends and in the present case is in the micron range. You can get rid of this thin layer by mechanical pressure is applied or the air is evacuated from the space in between, which makes it possible to achieve the intimate contact state mentioned above.

If the process is carried out by keeping the air layer constant at about 50 to 200 yes , the images are generally less clear than if the transfer of charges occurs between layers which are in intimate contact or in virtual contact with one another stand.

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Another variant is to charge the receiving material with the same polarity as the latent image and apply a rectified voltage to the back surface of the receiver. With this variant generally an image of slightly poorer quality than when using an uncharged receiving material. This is also the case with proceedings where the two layers are brought into intimate contact with each other, that is, with the application of mechanical pressure be performed. A process variant that is easy to carry out and high-contrast copies of good quality provides, consists in that you have a photoconductive layer, which completely or in part organic complexes consists (or contains such complexes) and which at a thickness of 8 to 15 Ai up to about 800 to 1600 volts can be charged, so exposed that on the Image areas voltages of at least about 500 volts versus voltages of no more than 300 volts on the non-image areas - ^ present. - - -

In a preferred embodiment of the process according to the invention, the procedure is that on the photoconductive Layer between the image areas (image points) and the image-free areas (points) a potential difference generated from about 500 to 900 volts.

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Photoconductive surfaces are based on complexes known from the German patent specification 1 127 218 »In these Complexes are combinations of compounds that act as a photoconductive substance Contain electron donor and an activator with the function of an electron acceptor. Among electron donor compounds all those compounds are to be understood which contain at least one aromatic or heterocyclic nucleus, which can carry substituents. Examples of such photoconductors are aromatic hydrocarbons, such as naphthalenes, anthracenes, phenanthrenes, benzanthrenes, chrysens, carbazoles, Oxadiazoles, triazoles, imidazoles, imidazolthiones, oxazoles, thiazole derivatives and others, among which the polymers one or more vinyl heterocyclic compounds, such as the derivatives of N-vinyl carbazoles, C-vinyl carbazoles, Vinyldibenzofurans, fluorene and analogous compounds are particularly preferred.

Compounds in particular can be used as electron acceptor activators which contain atoms in strongly polar groups, such as halogen atoms, cyano-, nitro-, -CO-, Ester, acid anhydride, carboxylic acid or quinone groups. Further details are from the above-mentioned German Refer to patent specification. It is expedient to use compounds such as fluorenones, in particular 2,4,7-trinitro-9-fluorenone, the 2,4,5,7-tetranitro-9-fluoro-jnon, occr: ucn

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- 7 compounds, such as chloranil and analogous compounds.

The proportion of the activator in relation to the conductive properties Substance can vary within wide limits. Small proportions are often sufficient. In certain cases it is expedient to choose molar ratios between the two compounds in the vicinity of 1: 1, the quantitative proportion of the activator is preferably 0.7 to 1.3 moles per mole of photoconductor.

The photoconductive material is prepared, charged and imagewise, i.e. according to the color separations, in a known manner of the original exposed.

The dielectric material used must be one which, once charged, has no noticeable effects Has charge losses; this is the case with one material

14 with a resistivity of at least 10 ohm χ cm. Electrically conductive paper backing coated with an insulating agent such as polystyrene, cellulose acetate, ethyl cellulose and the like, are suitable materials of this type.

In one of the modifications of the method according to the invention, the supports of the photoconductive layer and the dielectric layer Surface grounded during virtual contact. In this way, you get particularly rich in contrasts

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Pictures, the creation of a picture is also possible without grounding. The easiest way to have a virtual contact between To prepare the two layers consists in applying the receiving material with the help of two rollers, one on which is Cylinder the photoconductive layer is applied to the image without applying any external mechanical pressure. The tension required to move the paper is sufficient to make good contact. In this The rollers supplying the receiving material as well as the cylinder carrying the photoconductive material can easily fall be grounded.

The transferred latent image is then according to development processes known per se, in which dry developers or liquid developers are used, made visible. An advantage of the invention is that you can use liquid Provides developers with high-contrast images that are completely free of background pollution.

Liquid developers can be used which are suitable for development by spraying the liquid or aerosols (cf. British Patents 721 and 698 994), or those based on electrophoresis or cataphoresis phenomena (cf. British patents 835 044 and 755 496), provided, of course, that they contain a dye which is volatile ^{between 120 and 220 ° C.}

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Neither the type of development nor the type of developer are critical elements of the method according to the invention, as long as they correspond to the definition given above, i.e. one that is volatile within the given temperature limits Contain dye and correspond to the color separation of the original that they are to develop. Therefore, except the liquid developers specified above and dry developers are used, which generally consist of a sublimable dye and a resin compound (see e.g. Swiss patent application No. 16 831/73). Other dry developers are described in French patent 1,349,629. The development itself can when using dry developers by means of a magnetic brush or according to the so-called "cascade method" or by any other known method.

After developing each of the separations of the original, the developers are used, especially if you have dry toners used, fixed on the die to avoid any risk of damage to the image in subsequent operations to avoid. This fixation can easily be carried out under pressure and / or with slight heating of the base of the die to temperatures below those at which the dyes evaporate. Then the specified Operations (generation of the latent image, over-: r: j "';: j

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the same on a dielectric layer and developing and optionally fixing the toner) for each of the color separations of the original which are superposed on each other to reassemble the image to be reproduced.

The number of copies that can be obtained by heating the templates prepared as described above, depends on the amount of dye that can be evaporated and the rate of evaporation. Latter is a function not only of the temperature, but also of the more or less high affinity of the dielectric layer towards the dyes. For example, it has been found that a layer mainly containing ethyl cellulose depleted of dye much faster than one based on linear polyesters. It is therefore beneficial for the preparation of the dielectric surface to choose resins that dissolve the vaporizable dye and sufficient hold back in order to be able to make numerous copies. In this regard, the matrices are particularly advantageous Contain epoxy resins.

With the help of the matrices according to the invention, by simple Heating multiple copies in the colors of an original on a receiving surface will produce their nature varies with the chemical structure and the evaporation temperature of the dyes used.

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The surface of the receiving sheet can be flat or non-flat, be smooth or non-smooth, such as a textile surface. It can be one made of a non-woven fabric, from an art paper or around any impregnated, coated, coated surface or around a surface from acrylic polymers, polyamides or epoxy resins, vinyl resins, even a polyurethane one.

The invention is explained in more detail below using an example, but without being restricted thereto. Between two metal cylinders grounded by their axes, a strip of paper coated with an epoxy resin is pressed and a strip of commercially available zinc oxide paper on top of each other. On the zinc oxide layer one creates before them comes into contact with the paper coated with an epoxy resin by conventional methods by charging in the dark and discharge under the action of light, a latent image.

The two are located between the two metal rollers Strips of paper in virtual contact, closer contact being easily achieved by applying pressure increased between the rollers. By contacting, the latent image is transferred to the paper coated with the epoxy resin. Then it is made using a liquid developer that is sprayed with an injector

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with a hole or by dipping the paper in the developer. The excess liquid developer which has adhered to it is then freed from the developed image by running it between two pressure rollers, one of which is made of metal and the other of rubber, and then drying is carried out. The binder contained in the toner is fixed on the paper in this way. In this way, a matrix of one of the color separations of the original is obtained. The process is repeated on this template, changing the toner and the latent image, until the color composition of the original is achieved. This gives an intermediate copy, with the aid of which long by a few seconds heating at 120 ⁰ C in contact with a coated polyethylene terephthalate paper, a copy of the original image can produce. After the first copy, the stencil is by no means exhausted and several copies can be made one after the other by repeated heating. In the case of the last copies, the leaching of the template is partially compensated for by increasing the transfer ^{temperature to 210 °} C. or by lengthening the transfer time somewhat.

Instead of a zinc oxide paper are particularly suitable those papers, for example, a layer of 2,4,7-trinitro-9-fluorenone and from poly-N-vinylcarbazole in a molar ratio of 1: 1, based on the unit of the polyvinyl

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carbazoles, or a layer of 17.8 parts by weight of phenanthrene, 0.245 parts by weight of chloranil and 26 Parts by weight of polyvinyl acetate.

example

A photoconductive layer containing 2,4,7-fluorenone in polyvinyl-N-carbazole is applied to an aluminum foil a molar ratio of 0.8 to 1 (based on the monomer unit of the polyvinyl carbazole) and a thickness of 10 u. One fixes the layer on a metal drum and charges it to -1100 volts, one on one the ends of the coated aluminum foil exerts pressure,

With the help of a photographic lens of the RODAGON type (a product of the Rodenstock company) with a minimum light intensity of 1: 5.6 and a focal length of 210 mm the image of an original on the photoconductive layer through a lens, starting from a drum, which rotates synchronously, but in the opposite direction, and the picture with two Osram halogen lamps of the type 091 65D-11OO ¥ exposed.

-In the light bundle and in the vicinity of the objective lens, the selection red, green and blue of the is separated one after the other reproducing image; the selection is made using the "Graphic Special" filter from Agfa-Gevaert of the type

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L 599 C (red), U 525 C (green) and U 438 C (blue). The following exposure times are used:

6 seconds through the red filter, 4 seconds through the green filter and 11 seconds through the blue filter.

The charge acceptance in the image generating zone is 900 V and 300 V in the remaining zones, after the transfer of the charge image on the dielectric paper, the voltage in the image zone is 290 V and less than 10 V in the non-image zone Zone.

The latent electrostatic images are then each with a liquid developer based on the following has been produced in the manner specified with the dyes listed below:

yellow dye red dye

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blue dye

The three images are superimposed so that after the last one has been developed, the dielectric paper bears an image containing the three color elements of the original. This image is then brought into contact with a sheet of receiving paper and ^{heated to 200 °} C. for 15 seconds. In this way, a true-to-color copy of the original is obtained, the colors of which have been broken down into the three primary color elements and reassembled after the transfer.

The receipt sheet can be produced as follows, for example:

A sheet of SYNTOSIL ^ art paper from Zurich paper factory AN DER SIHL is coated in an amount of 5 g / m with a dispersion containing 5 % AEROSIL®-SiO ₂ from DEGUSSA, Frankfurt, and 10 % ETHOCEL © from DOVi CHEMICALS CO. in a mixture of 50 % methyl ethyl ketone and 50 % ethanol. After drying for 30 seconds, the sheet of paper thus produced can be used as a copy-receiving sheet in the above-described process.

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The dielectric paper can be made as follows:

A roll of paper which is coated with an electrically conductive resin ECR 34 (from DOW CHEMICALS) and whose surface resistance is 0.2 to 2 χ 10 ⁴ Ohm / CD is provided with a layer which has the following composition: 30 parts ARALDITE® 488 N 40 (from CIBA-GEIGY AG), 5 parts LYOFIX CH® (from CIBA-GEIGY AG) and 0.5 part UVITEX®SOP (from CIBA-GEIGY AG) and 0.5 part ethyl cellulose ETHOCEL N22 from DOW CHEMICALS CORP in methyl ethyl ketone. After drying, you get a smooth and shiny coating. If, on the other hand, a matt coating is desired, it is sufficient to add 1% silica gel AEROSIL® (from DEGUSSA) to the above composition and to provide the paper with two successive layers.

Patent claims:

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Claims (15)

Claims , .- · Process for the production of matrices for manufacture of colored reproductions, characterized in that one a) successively and electrostatically the color selections latent images corresponding to an original from the photoconductive layer on which they are successively are generated, transferred to a dielectric layer in such a way that they overlap, b) corresponds to each of the thus transferred latent images prior to transmission of the next picture using a dry or liquid developer containing a dye which passes between 120 and 22O ⁰ C in the vapor state, and the initial separation of the transferred image, develops and c) after each development, the image obtained on the dielectric Fixed surface. 2. The method according to claim 1, characterized in that there is used developers containing dyes, their Sublimation curves between 170 and 190 ° C are very close together. B 0 9 R 8 5/1 2 7 7 3. The method according to any one of the preceding claims, characterized in that at least one of the developers used contains one of the following dyes: 3-hydroxyquinophthalone, 1-Amino ^ -phenoxy ^ -hydroxyanthraquinone, 1-Amino-Z-methoxy ^ -hydroxyanthraquinone, 1-amino-2-chloro-4-hydroxyanthraquinone, 1,4- or 1,5-diisopropylaminoanthraquinone, 5-isopropylamino-8-amino-1,4-dihydroxyanthraquinone and Colorants of the formula " 0 NH ₂ T Γ N-alkyl, wherein the Alkyl group contains 1 to 3 carbon atoms. 4. The method according to any one of the preceding claims, characterized in that there is used developer which Contain monoazo dyes. 5. The method according to any one of the preceding claims, characterized in that one for developing the images liquid developer used. 6. The method according to any one of the preceding claims, characterized in that one for developing the images solid developers, preferably magnetic developers, are used. 509885/1277 7. matrices that are suitable for the production of colored copies, characterized in that they are on a dielectric, non-photoconductive surface an overlay of color separations of an original color made using electrophotographic and dyes containing developers have been developed using such dyes that are between 120 and 220 C in pass the steam state. 8. matrices according to claim 7, characterized in that they have dyes whose sublimation curves between 170 and 190 ° C are very close together. 9. matrices according to claim 7 or 8, characterized in that they contain at least one of the following dyes: Hydroxyquinophthalone, 1-Amino ^ -phenoxy-A-hydroxyanthraquinone, i-Amino ^ -chlor- ^ hydroxyanthraquinone, 1,4- or 1,5-diisopropylaminoanthraquinone, 5-isopropylamino-8-amino-1,4-dihydroxyanthraquinone, 1-amino-2-methoxy-4-hydroxyanthraquinone and Dyes of the formula 0 N-alkyl, in which the - ULK ^{1 line}
Alkyl group has 1 to 3 carbon atoms. Π Π RP $ / * \ '} 7 7 10. matrices according to claim 9 »characterized in that they are in addition to at least one of those specified in claim 8 Dyes still contain one or more dyes which change into the vapor state under similar conditions. 11. Matrices according to one of claims 7 to 10, characterized in that their dielectric surface is an epoxy resin contains or consists of. 12. Use of a die according to one of claims 7 to 11 for the production of colored copies. 13. Use according to claim 12, characterized in that a 'die according to one of claims 7 to 11 in the Contact with a receiver sheet warmed to at least 140 ° C for at least 15 seconds. 14. The method according to claim 12, characterized in that a die according to one of claims 7 to 10 is heated in contact with a sheet of paper which is coated, coated or impregnated with a resin which has an affinity or a dissolving capacity for dyes, which change into the vapor state between 120 and 220 ^{0 C.} fvO 9 R 8 5/1 2 7 7 15. Color copies, characterized in that they are produced by the method according to at least one of claims 12 to 14 have been. fi09885 / 1277