| 摘要 |
PURPOSE:To prolong the useful life of a thermal head, by using a heat-resistant organic material such as a polyimide resin having a coefficient of linear expansion comparable to or lower than that of a protective layer, as a material for forming a heat-accumulating layer. CONSTITUTION:A base layer 2 having a thickness of about 60mum and formed of a glass having a coefficient of linear expansion of 0.4X10<-6> is provided on a heat-resistant insulator substrate 1 formed of alumina having a coefficient of linear expansion of 6X10<-6>. A heat-accumulating layer 3 is provided only on the base layer 2 by applying a polyimide resin having a coefficient of linear expansion of 3X10<-6> by spin coating, spray coating, printing or the like, followed by sintering to effect condensation. Then, a plurality of heat generating resistors 4 formed of TaN or the like in a thickness of about 500Angstrom and a conductor layer 5 formed of Au or the like in a thickness of about 1mum for supplying electric currents to the resistors 4 are provided on the heat- accumulating layer 3, and a protective layer 6 having a thickness of about 6mum and formed of Ta2O5 having a coefficient of linear expansion of 3X10<-6>/ deg.C is provided on a top surface so as to protect the resistors 4 from oxidation and abrasion, thereby completing a thermal head. |
