Novel Approach to Plastic Card Overcoating Process

Abstract

Plastic cards are widely used in various industries all over the world. Many on-demand non-embossed pictured cards require overcoating (also referred to as laminating) processes for surface protection from fading, abrasion, alteration and counterfeiting. There are several lamination types, such as wet lamination, dry lamination, hot-melt lamination and extrusion lamination. The focus on this paper is the hot-melt lamination type which utilizes heat and pressure to adhere the film on the card. The laminating / overcoating layer material can be clear material with antiabrasion capability or hologram material for authentication. Typical overcoating process in the thermal transfer card printer is done by thermal printhead or heat roller. This paper suggests the heating head for this process. The heating head works on a very similar principle as the thermal printhead. The heating resistive element and temperature sensing element are placed on the alumina head substrate. When power is applied, the resistive element generates heat for the overcoating material to thermally adhere to the plastic card surface. Unlike the thermal printhead, however, which has hundreds of tiny heating elements, the heating head has one contiguous heating element. The construction of the heating head gives more robust thermal performance and even heating capability across the overcoating material on the card surface. In comparison to a heat roller, the heating head can be used on-demand and does not require the constant pre-heating while the unit is on stand-by (more “eco-friendly” efficiency and safety).