THERMOGRAPHIC PRINT
Print with thermographic printers
PVC cards, or more commonly called plastic cards, have a smooth surface that requires printers other than the most common classic printers, laser or inkjet.
The procedure used, specific for plastic cards, is thermal transfer.
The thermal transfer consists in depositing on a flat and smooth support a colored layer coming from a tape. This transfer is possible thanks to the thermal head of the printer which allows heating of the colored layer of the ribbon. The latter turns into gas which solidifies in the surface layer of the plastic card.
This process is also called sublimation.
Monochrome printing
When there is only one color printed, we speak of monochrome printing. This type of printing can be economical especially when using pre-printed cards. It is ideal for cards that do not require color identification elements (e.g. photos).
Color printing
Just as in professional printing, thermal printers use the superposition of three primary colors (yellow, magenta, cyan) to give more depth to the image.
This process allows professional cards to be obtained with absolute color fidelity both as regards images and logos, with a high resolution quality of 300 0 600 dpi. A professional resolution that offers an exceptional "smoothed" result.
Direct and Indirect printing
Direct: direct printing is understood by means of hot transfer of color by means of a process which brings the print head closer to the color or monochromatic print ribbon by placing it directly on the badge and thus transferring it to the card. This technique is optimal for printing and customizing the variable data on the cards, especially if the cards are perfectly planar (absence of antenna and chip) and if printing of a background full of color is not required since a limit of this technique is that the head does not reach the edge of the cards and therefore leaves a few tenths of a millimeter unprinted. The border printing is inhibited to protect the print head which, being in direct contact with the card, would risk breaking some dots impacting the border.
Indirect or re-transfer: indirect means the printing by hot transfer of the color always through the print head but on a film and not directly on the card, the personalized transparent film will be applied automatically on the card always through heat and pressure. It is certainly the best technique for personalizing cards beyond the edge, even if cards that are not perfectly flat are used, such as in the presence of chips and antennas. From a graphic point of view, the result is certainly better and the result compensates for the higher final cost also due to the use of a set of ribbons (color and film) instead of just one. It also avoids having to discard badly printed RFID cards.
Rewritable printers
If rewritable cards are used, ribbons are not used for printing the cards, but it is the card itself that contains a heat-sensitive material that becomes visible when heated to a temperature of 180 ° C and then cooled quickly. The same card can then be used again by deleting the data entered when a lower temperature is applied, generally between 110 ° C and 160 ° C, thus dissolving the color. This is due to the presence of two chemicals that combine when a critical temperature is reached. In this way the procedure is reversible, so that the same card can be canceled and reprinted up to 500 times.
The heat is produced by a thermal head inside the printer, for some printer models the head is different thus having printers that personalize only the rewritable card and sometimes with the same head it is possible to manage both print processes with ribbons and without.
The rewritable cards:
The heat-sensitive material is plasticized on a substrate to form the virgin plasticized card. The most common substrates are PVC for 0.76 mm thick cards and PET for 0.25 mm thick cards.
PVC cards can be made with magnetic strips and contactless microchips to facilitate the execution of sophisticated applications.
PET cards often have a magnetic layer on the opposite side of the rewritable side.
Advantages:
- Savings:
- No cost for tapes
- Reusable cards (up to 500 times)
- Quick update capability:
- The data can be modified locally when the need arises
- Wide field of applications:
- It can be associated with a magnetic strip or a contactless microchip