| 摘要 |
PURPOSE:To obtain a thermal head suitable for a concurrent drive type by using a multi-layered wiring section consisting of an insulating layer requiring no high- temperature process with the second insulating layer coated with a photo-sensitive polyamide varnish and three or more layered conductive layers. CONSTITUTION:The whole surface of the region of a multi-layered wiring section of an insulating base plate 11 is coated with a photo-sensitive polyamide varnish, and exposed to a mercury lamp through a mask. The polyimide varnish coat is developed, washed and then hardened by heating at about 350 deg.C. The second insulating layer 23 with a given opening may also be formed on the first insulating layer 20 without damaging the layer 20. Three or more-layered conductive layers 19, 22 and 25 are provided, and the area of the earth electrode is enlarged to increase the earth current capacity. |
