Modelling of thermal printers

This paper is concerned with the temperature field produced by a thermal printer head. Such heads are used to provide high quality prints of electronically stored images. In this system, a thin dye-layer, sandwiched between two copolymer sheets, is heated by a thermal head and dye diffuses into the receiver sheet producing a small dye-dot. The picture is made up of a large number of such dots. The basic aim is to determine the amount of dye which is eventually diffused into the receiver sheet when the heating is turned off and the system has cooled down. However, the amount of dye which diffuses into the receiver sheet depends on the temperature field because the diffusion coefficient is a sensitive function of temperature. In the thermal printer system, each head is heated by an electric current which is carried by gold leads. In this paper, we show that the heat loss through these leads has an important effect on the temperature field produced by the head and therefore, strongly influences the amount of dye transferred.