IT1046521B - Electrothermal printer using ordinary paper - and having long contact time through two-layer plastics ribbon - Google Patents

Abstract

An electrothermal printer, intended for printing a line of type comprises a printing head which moves continuously along the line and comprises a row of resistant printing elements extending perpendicularly to the line of type. These elements are electrically heated in synchronisation with the movement of the pressure head. A heat-sensitive inked ribbon constituted of support strip of thermally penetratable material and a coating is introduced between the printing head and the recording medium or paper. A pressure device, typically a lever mechanism tensioned by a spring, presses the printing elements against the ribbon and thus presses the coating onto the paper while the pressure head is in movement. Pref. the backing plate behind the paper has a flexible layer of material on it, and a second coating of plastic material in contact with the paper. Each of the thermal elements possesses a partially cylindrical surface, the generatrix of which is perpendicular to the line of type. The recording paper is pref. ordinary, non-sensitive paper, and the ribbon backing strip is 7-20 mu thick, the coating being 2-4 mu thick and comprising a reversible thermoplastics resin, a plasticiser and a pigment. Pref. matls. for the support strip are polyethylene glycol terephthalate or polyethylene, the resin for the coating comprising a styrene resin, a terpene resin or an eposy resin. Ordinary paper is used. Due to the long contact time, low pressure can be applied.