| 摘要 |
PURPOSE:To reduce the thermal effects of a rise in the temperature of heat generating elements to be affected upon adjacent dots, by providing a substrate of a thermal head with a cooling-liquid passage in proximity to a plurality of heat generating elements, and causing a magnetic fluid to flow through the circulating passage as the cooling liquid, thereby forming a magnetic field across the thermal head. CONSTITUTION:When printing is started, the temperature of heat generating element 7 is rapidly raised, and heat is transferred to an ink sheet 5 and also through a head substrate 12 to a magnetic fluid at a point P. The magnetic exceeded, upon which the fluid at the point P is moved in the direction of an arrow B by being pushed by a force generated by a magnetic force of the fluid at a part not yet heated. Since the fluid at a low temperature is supplied through a circulating passage 10 to the point P, the heat generating element 7 is rapidly cooled. Thus, a heat-dissipating effect is poor during printing because a cooling liquid does not flow, but the effect is rapidly increased when printing is finished, so that high-speed printing with high thermal efficiency can be performed. |
