DE2450500A1 - Transfer printing directly from electrophotographic material - with toner image contg sublimation dyes, for sharp multi-coloured prints - Google Patents

Abstract

In an electrophotographic recording process using a toner contg. sublimation dyes and opt. transfer ais, the electrophotographic matl. used for the prodn. of the image also acts as intermediate support for these dyes, which are then transferred to a receptive matl. by heating. Used for printing plastics films and synthetic fibres, e.g. homo- and copolymers of vinyl acetate, alcohol and chloride, vinylidene chloride, acrylic cpds., alkylenes, alkylenecarboxylic acids and esters, styrene, alpha-methylstyrene, maleic acid cpds., cellulose esters and ethers, polyesters, polyamides and condensn. resins. Only one transfer is necessary, even for multicoloured prints, and very fine detail with high contour sharpness can be obtd.

Description

Methods and material for making reproductions The invention relates to a method for producing reproductions, their image markings are produced from compounds that can be transferred in the heat and in whole or in part correspond to an electrophotographically generated latent charge image which is associated with With the help of an electrostatic toner system, which is heat transferable Compounds (hereinafter referred to as sublimation dyes) and, if necessary, transfer aids contains, has been developed.

The invention also relates to a material for performing this Procedure.

It is known to use suitable intermediate carriers, such as papers, metal foils and the like, for example by printing, writing with transfer materials or to apply a color size in the range of 140 - 2200 by coating Contains sublimable dyes. These print patterns generated predominantly in mirror image are brought into intimate contact with a suitable recording material, after which the sublimation dye passes into the receiving material when the back is heated.

This process has been especially made for printing on textiles Synthetic fibers with recurring patterns have found their way into technology but uneconomical if it is for small editions, for reprographic purposes or, for example, should be used for addressing, since the manufacture the printing form is too expensive, too complicated and too tedious.

The invention has now set itself the task of a reprographic To create a process with an intermediate carrier for a sublimable dye image, the different templates and diverse applications adaptable and also is easy to use0 It has now surprisingly been found that electrophotographic effective photoconductor layers both as recording material for creating a electrophotographic toner image containing heat sublimable dyes contains, as well as an intermediate carrier for the transfer of this sublimable dye image suitable is. Electrophotographic recording materials are for the invention The process is particularly valuable when its support materials are heat-resistant Form in particular as papers, nonwovens or metal foils.

In the German Offenlegungsschrift 2 148 911 an electrophotographic Stencil described, the image of which consists of a pattern of toner particles that contain a sublimable dye. however, the toner image is on a separated photoconductor layer imagewise generated and then on electrostatic Paths transferred to an intermediate carrier, which is then used for thermal transfer of the Sublimation dyes on a suitable transfer material is used.

However, this solution has significant disadvantages in the form in which to achieve the task set an expensive and failure-prone Apparatus is used in which the same photoconductor is continuously used to generate different images is used. Since in these devices there are often considerable If heat occurs, it cannot be ruled out that the sublimation dyes pass into the photoconductor layer and change them as a result of their sensitization and renders the photoconductor itself unusable. In contrast, the invention uses Process for each exposure an unused electrophotographic material and at the same time uses it as an intermediate carrier for transferring the dye molecules.

While in the German Offenlegungsschrift 2,148,911 outlined The process that the dye bill undergoes a double transfer is with one The method according to the invention only requires a one-time transmission. In particular for reprographic purposes, where there is a need to transfer the finest details at high levels When it comes to the definition of the contours, the method according to the invention is considerably greater than that mentioned above think.

According to the method according to the invention, it is now still possible on a photoconductor layer, which should continue to serve as an intermediate carrier, in aufe successive work steps. several o toner images, df e different if necessary can be colored and contain differently colored sublimation dyes, to be deposited in such a way that a multicolored image can be applied to one joint operation suitable carrier material becomes transferable.

As a carrier for the photoconductor layers suitable as an intermediate carrier papers, nonwovens made of cellulose, glass or synthetic fibers, carbon fibers nd iietallfaserrl, foils made of metals, heat-resistant plastics, cell glass or other flat-shaped structures made of temperature-resistant material have proven successful.

To achieve photoconductivity, these carriers are when they not sufficiently electrically conductive for the construction of electrophotographic material are, preferably coated with conductive layers or with conductive materials filled.

Particularly valuable are those applied to the surface by vapor deposition in a vacuum Metal layers, but also conductive resins, etc. are particularly useful of cellulose suitable as a carrier.

It has now proven to be particularly expedient for the method according to the invention found to use such photoconductor layers that are durable up to 2500 Carriers have or which either adhere firmly to metals or their photoconductor layer consists predominantly of inorganic heat-resistant substances.

As photoconductors firmly adhering to metal are in particular those according to German patents 1,246,407, 1,246,408, 1,278,241 and 1,296,001 Photoconductor layers useful. Your through reaction of isocyanates and / or epoxides The photoconductor layers formed have excellent adhesion to metal in particular aluminum and can no longer be melted. From the inorganic photoconductor layers, For example, the photoconductor zinc oxide, zinc sulfide, cadium sulfide, titanium dioxide or contain photoconductive glasses, have been chosen for the process according to the invention also found to be particularly useful. The utility value of the invention Process can be enhanced by using thermosetting resins such as thermosetting acrylates are used to bond the photoconductors, and if that The ratio of binder to inorganic photoconductor is increased to 1:12. The photoconductor layer should also have as little or no such binders as possible that really dissolve sublimation dyes.

These photoconductor layers suitable for the method according to the invention other substances, such as transfer aids, oxidizing agents, Non-stick substances, etc. can be added, which improves the transmitted Enable toner image. Such connections have proven to be particularly valuable, the transfer temperature of the sublimation colorants contained in the toners lower or make it more uniform It is known that the sublimation temperature of the individual dyes fluctuates over a wide range. While easily sublimable Dyes are transferred from the intermediate carrier to the receiving material at a temperature of 1400 pass over, there are other dyes that cannot be transferred until 2200.

The electrophotographic one provided with the above image marks The intermediate carrier is brought into intimate contact with a suitable receiving material and preferably heated from the rear to 130-2500, the sublimable Dye, for example in molecular form, evaporates and enters the heated receiving material diffused. It is also possible, through the action of suitable radiation sources, especially of ultra-red and coherent light deposited on the intermediate support Transfer dyes.

This transmission method differs significantly from the conventional heat transfer processes of thermal copying or of electrostatic adhesive toners. While with the latter always one containing in particular color pigments and binders Dye mass is transferred, which then sticks to the surface of the receiving material, the heat-sublimable dyes are in finely dispersed form, for example transferred as glass-like molecules or molecular aggregates, which then into the carrier material diffuse in the area of the thermal gradient and in this, for example, in shape a solid solution.

This is why these dye images also have a much higher utility value, as they cannot be rubbed off the surface or washed off.

The electrophotographic material suitable as an intermediate carrier is for producing a reproduction according to the known methods of electrophotography charged and then exposed imagewise, with a latent electrostatic Charge image is created. This electrostatic charge image is created with a special electrostatic toner system developed.

For this purpose, electrostatic toner systems are used, which accordingly their function differently from the usual electrophotographic toners are. They are characterized in that they are sublimable in their toner particles Dyes included, these for example in molecular form by heating to a temperature between 1200 and 250 from the intermediate carrier to the Transferring the receiving material0 These electrostatic toner systems can use so-called Be liquid toner. These are particularly valuable insofar as they are produced solely by evaporation of the dispersant achieved the fixation of the toner part on the intermediate carrier It is also possible to use solid toner to develop the electrostatic To use charge image, such solid toners are also suitable that after Application can be firmly anchored to the intermediate carrier by melting the line.

It is still possible to have the electrostatic image marking on the intermediate carrier by spraying on suitable electrostatically charged particles such as liquid droplets, aerosols, dust dispersions in gases, etc. Particles contain sublimable dyes. This is how it works, for example by using an aerosol which contains sublimable dyes and the charged when passing through an electrostatically charged ring-shaped electrode is, by spraying on an electrophotographic intermediate carrier, corresponding To generate image markings.

The surface of the suitable receiving materials consists predominantly made of polymeric organic compounds, also called plastic films or synthetic fibers may exist.

Homo- or copolymers of vinyl acetate are particularly useful, Vinyl alcohols, vinyl chloride, vinylidene chloride, acrylic acid compounds, alkylenes, Alkylenecarboxylic acids and esters, styrene, α-methylstyrene, MRleic acid compounds Among other things, cellulose esters and ethers, such as ethyl cellulose, benzyl cellulose, Cellulose propionate or acetobutyrate are suitable.

But also the polyesters of terephthalic acid, carbonic acid and adipic acid, also polyamides such as nylon 66 or Perlon (R) and other textile fibers, such as Orlon (R), Dralon (R), Terylene (R), and condensation resins are useful.

The photoconductive intermediate carrier according to the invention can be developed in the State for one-time @ ilderz @@ gung, but it can also, if sufficient Amount of toner deposited can be used for multiple imaging. Forner it is possible to transfer the dyes of the toner image to the toner material to add further colored components in such a way that the one used for the transfer The intermediate carrier can still be used as a copy or as a copy.

The reprographic method according to the invention is particularly suitable for reproductions on suitable receiving materials in small runs, wherever traditional printing methods are too expensive or slow. In particular, @u name: cartographic transfers, production of color separations for the graphic Commercial, checking of color proofs, addressing and labeling of plastic envelopes or packaging materials, etc.

The method according to the invention can also be used for textile printing, e.g. for the production of placemats, souvenir items, club flags and for advertising purposes. This makes it possible, for example, to print advertising on textiles in a simple manner to be created individually in small quantities and at short notice. A special purpose the method according to the invention lies in the production of templates for overhead projectors. With this method it is possible to produce film materials that contain no other components besides the dye image, which for example yellow with prolonged exposure or due to chemical reaction when exposed to light damage the foil. If you disregard the elaborate print products on foils, To date, no process has become known which is as perfect as this Way is suitable for generating templates for overhead projectors.

To carry out the process according to the invention, preference is given to using one of the common electrophotographic copiers. One changes episcopes so that a mirror image of the original is created on the copy. Depending on the development technique of the existing device one uses a solid or liquid electrostatic Developer that can be used in the same way as for making copies is.

The invention is illustrated below by way of example.

Example 1 In 100 1 of toluene, 7.0 kg of an acrylate resin, which contains approx. 2-8% free carboxyl groups, 3.5 kg of a copolymer of vinyl acetate and partial maleic acid esters dissolved. 100 kg of photoconductive material are added to this solution Entered zinc oxide and dispersed in several stages so that the zinc oxide in Primary particle is present.

A solution of 8 g of bromophenol blue and 12 g uranine A in 2 1 methanol and 1 1 ethanol are added to the batch.

On a cellulose paper of approx. 70 g / m2, which is in the sheet of table salt and humectants and surface conductive cover strips with not or over 2500 fusible binders such as starch, cellulose ethers, amino starches, aminoplasts, thermosetting acrylates or the like. contains 60 g of the above photoconductor preparation applied by machine and dried at max. 1100.

A sheet is used to produce the photoconductive intermediate carrier of the photoconductor paper by dark discharge of a spray corona of 10 KV negative charged. Is intended to have a sideways dye image on top of a non-transparent one Receiving material are generated, the imagewise exposure is carried out in such a way that that the latent charge image corresponds to a positive mirror image of the original.

The latent charge image is with a liquid toner containing 10 g of one sublimable dye cellitone blue G Color Index 64 500 cellitone blue FPB Color Index 62 035 Cellitone Scarlet B Color Index 11 110 Cellitone Fast Yellow RR Color Index 11 345 Sudan Blue II Color Index 2 882 contains, wetted, and excess Toner is removed by air knives or nippers, after which the in love ones Portions of the dispersant are evaporated. The intermediate carrier is now for thermal Transfer usable.

It is covered with a film or a fabric made of polyester, and the whole thing is heated on the back, for example in an ironing press, to 180 - 2500, the dye contained in the toner from the intermediate carrier in about 1/2 min. into the Receiving material passes over, the image is ready after removal from the heating press.

Claims (23)

Claims 1. Process for the production of reproductions, their image markings generated from heat transferable compounds; are and in whole or in part correspond to an electrophotographically generated latent charge image which corresponds to An electrostatic toner system has been developed which is used in the Heat transferable connections and possibly Transmission aid, marked by the fact that the electrophotographic material used for image production at the same time o-ls Zw Shear carrier for the sublimation dyes is used, which is then developed on the transferable toner image located electrophotographically active intermediate carrier is transferred by heating to @in receiving material. 2. The method according to claim 1, characterized in that on a Photoconductor layer, which should continue to serve as an intermediate carrier, in successive Work steps several toner images, which may be colored differently and which contain differently colored sublimation dyes, deposited and a multi-colored image on a suitable carrier material in a joint operation is transmitted. 3. The method according to claim 1 or 2, characterized in that such Photoconductor layers are used that have a 250 ° resistant carrier or these either adhere firmly to metals or their photoconductor layer predominantly Dimensions made of inorganic heat-resistant materials. 4. The method according to claim 1, 2 or 3, characterized in that the photoconductor layers other substances, such as transfer aids, oxidizing agents, Non-stick substances, among other things, are added to improve the transferred Enable toner image. 5. The method according to claim 4, characterized in that such compounds The transfer temperature of the suppression dyes contained in the toners were used lower or make it more even. 6. The method according to one of the claims, characterized in that that the electrophotographic intermediate carrier provided with the @ildmarks brought into intimate contact with a suitable receiving material, and preferably is heated from the back to 130-250 °, the sublimable dye evaporated, for example, in molecular form and cindiffused into the heated receiving material. 7. The method according to any one of the preceding claims 1-5, characterized characterized in that the dyes deposited on the intermediate carrier by action suitable radiation sources, especially ultrared and coherent light will. 8. The method according to any one of the preceding claims, for generating of the toner image electrostatic toner systems are used in their death particles Contain sublimable dyes, this @ for example in molecular form by Heating to a temperature between 1200 and 2500 from the intermediate carrier to the receiving material transfer. 9. The method according to claim 8, characterized in that as electrostatic Toner systems liquid toner can be used. 10. The method according to claim 8, characterized in that for development of the electrostatic charge pattern, solid toners are used, especially those which are firmly anchored to the intermediate support by melting down after application. 11. The method according to claim 8, characterized in that the electrostatic Image marking on the intermediate carrier by spraying suitable electrostatic charged particles such as liquid droplets, aerosols, dust dispersions in Gases and others containing sublimable dyes in their particles will. 12. The method according to any one of the preceding claims, characterized in, that the photoconductive intermediate carrier when a sufficient amount of toner is deposited is used for multiple imaging. 13. The method according to claim 12, characterized in that after transmission of the dyes of the toner image, further colored components are added to the toner material that the intermediate carriers used for the transfer continue to be used as a copy or Working mat usable mesh. 14. Material for carrying out the method according to claims 1-13, characterized in that the intermediate carrier is in heat-resistant form. 15. Material according to claim 14, characterized in that the intermediate carrier from a photoconductor layer on paper, cellulose, glass or mineral fiber fleece, Carbon fibers, and metal fibers, foils made of metals, heat-resistant plastics, Cellulose glass, or another surface-shaped structure made of temperature-resistant Material. 16. Material according to claim 15, characterized in that these materials are covered with conductive layers or filled with conductive materials. 17. Material according to claim 16, characterized in that the photoconductive Layer is a metal layer applied to the surface by vapor deposition in a vacuum. 18. Material according to claim 16, characterized in that the photoconductive Layer made of conductive resins. 19. Material according to claim 18, characterized in that the photoconductor from three-dimensionally crosslinked, epoxies and / or isocyanate-containing compounds is formed. 20. Material for performing the method according to claims 1-13, characterized in that the Ezipfangsmaterialier predominantly in their surface consist of polymeric organic compounds, also called plastic films or synthetic fibers can be present. 21. Material according to claim 20, characterized in that the polymer Compounds Homo- or copolymers of 7 inyl acetate, vinyl alcohols, vinyl chloride, Vinylidene chloride, acrylic acid compounds, alkylenes, alkylene carboxylic acids and esters, Styrene, α-methylstyrene and / or maleic acid compounds are 0 22. Material after Claim 20, characterized in that the polymeric compounds are cellulose esters and ethers are, in particular ethyl cellulose, benzyl cellulose, cellulose propionate or acetobutyrate. 23. Material according to claim 20, characterized in that the polymer Compounds polyester of terephthalic acid, carbonic acid and adipic acid, polyamides, Polyacrylonitriles, polytherephthalic acid esters and / or condensation synthetic resins are.