Thermal transfer printing machine for printing images on articles by means of a heated pad, particularly for printing images in cavities or recesses

Abstract

A thermal transfer printing machine with stationary support elements for supporting an article and a thermal transfer assembly vertically movable above the support elements, between a raised rest position and a lowered working position is disclosed. The machine has a surface heated transfer pad, supply and guide devices, a flexible printing ribbon which carries thermally transferable ink images, a position sensor providing electrical signals indicative of the vertical position of the transfer pad and a control unit with a learning phase, said control unit causes a descent run of the thermal transfer assembly, until the transfer pad engages with an article of a predetermined type. The position sensor detects and stores reference data characterizing descent run and the control unit initiates a subsequent descent run towards an article of the same type, comparing the reference data to the current descent run data, and stopping printing when an anomaly is discovered.