2. Technical description

2.1 Magnetic medium

The heart of any magnetic printer is the magnetic medium that records the latent magnetic information in the form of a matrix made up of zones, called dots, with strong magnetic field gradients on a microscopic scale. In order to meet these specifications, the recording layer must be made of a hard ferromagnetic material (whose coercive field µ ₀ H _c is greater than around 10 mT, figure 2 )