Foil transfer on toner

also Digital Metal®

The transmission of transfer layers of a special film on printed toner layers for surface finishing generated visual effects, such as are known from hot foil stamping or cold foil finishing. This printed by laser or copier materials such as paper or cardboard can be provided in a simple manner with metallic effects. Is employed for a special multiple layer film, to be detached from the under the action of temperature and pressure, coloring layers, and fixed on the material surface.

Technical Background

The transmission principle is based on an interaction between the toner of the digitally printed material transfer layers of the film adhere to the printed areas. Are utilized, the thermoplastic properties of the toner and the adhesion and barrier layer of the film. At temperatures above 80 ° C, the surfaces of the thermoplastic constituents melt. The melting of the interface leads to the detachment of the transfer layers. Due to the melting of the adhesive layer and toner particles to act as the adhesive, these substances are combined with each other under the action of pressure. By following cooling, the transfer layers are permanently affixed to the substrate surface.

Then a overprinting in digital printing can be performed with conventional or UV digital printing toners. Thus, a wide variety of metal colors and halftone effects can be generated despite the monochrome film. Can connect the substrate be provided if required with a paint finish.

As a film, a modified stamping foil is used. The basic layer structure and the production resembles the films for cold foil transfer or hot foil stamping. The adhesive layer is specially adapted to the toner.

For the toner coating also certain stamping foils for e.g.. Plastics or plastic coatings can be used in addition to the process-specific films.

Since the color of the toner proves to have no effect on the transfer layer transmission, can significantly cheaper black toner, which are used in most copiers and laser printers. The film is opaque, so that the ink does not affect the perceived color.

The method is equally applicable in the digital sheetfed and web printing.

Effect

The visual effect of the film transfers to toner is similar to the cold foil transfer or a hot foil stamping. Iridescent and reflective surfaces, such as metal, water or glass, can be implemented realistically. On the basis of only a standard silver film can be formed by overprinting almost any desired color. By the use of special films, it is also possible to transfer holographic effects.

Through the realization of the processing in the digital print individualization, personalization and numbering of the printed product is easily possible. A haptic effect remains off, however, since no deformation or tactile surface change takes place.

Application Possibilities

The transfer film can be used in the refining of one-offs and small runs, for example in the individualized label printing, the binding on demand and commercial printing. For individual, personalized greeting cards, photo books presents the novel method is an interesting type of finishing.

Effect films or film combinations can also for example on tickets or packages to protect against counterfeiting applicable in the field of security printing. In addition, with the help of this application cost sample copies to estimate the effect of a hot foil stamping prepare before an expensive embossing die is created.

Limitations

When foil transfer printing paper with a basis weight of 80 ... 350 g/m2 and a thickness of 0.1 ... 0.5 mm can be used. Ideal are coated papers with a smooth surface, first ensure high print quality as a prerequisite for optimal film transfer. Structured paper or board surfaces or unevenness of the surface cannot be completely filled with toner at high dot densities, also the separating and adhesive layer thicknesses of the film are also too low to fully compensate for this unevenness, which is a partial, afflicted with defects transfer of motive has resulted.

With increasing surface coverage and thus increasing the toner layer thickness, the quality of the transfer coating increases, e.g., the transmission is completely and evenly, especially in large-scale designs. At low toner layer thickness leads to defects or incomplete transmission of the subject.

Regarding the resistance must be kept in mind that the films are sensitive to mechanical stress. Therefore, an additional surface protection as an aqueous or UV varnish or a foil lamination is recommended.

Costs

Compared to hot foil stamping and cold foil transfer the preparation for expensive embossing plates or printing forms. The unit costs are independent circulation, thus the method for processing small orders and profitable by implementing digital printing an affordable finishing at number one is already possible.

Sources and additional literature

[1] LEONHARD KURZ Stiftung & Co.KG: Metalleffekte im

Digitaldruck; Pressemitteilung, Fürth 2012

[2] LEONHARD KURZ Stiftung & Co.KG: Metallic trifft

Digitales; Bindereport 6/2012, Hannover, Seite 24

[3] Nadler, Peter:

Drucksachen mit dem gewissen Etwas; Publisher 3/2012, Winterthur, Seite 47