Patent ID: 6950117
Filing Date: 2005-09-27
Classification: B41J

Abstract:
1. A thermal head, comprising: a heat insulating layer formed on a top surface of a substrate; plural heating elements formed of plural heating resistors and power feeding members on a top surface of the heat insulating layer; and a protective layer that covers at least surfaces of the heating resistors and the power feeding members, wherein the substrate contains glass having a phase-separated, heat treated composition and that protrudes at a predetermined height at a position where the heating element is formed to form a projecting section, wherein the heat insulating layer includes a two-layer structure of: a first heat insulating layer containing a porous glass layer obtained by selectively eluting one composition of the glass whose phase is separated, which is partially formed on the projecting section; and a second heat insulating layer containing ceramic of low thermal conductivity stacked and formed on top of the first heat insulating layer, and wherein a mask layer covers a top surface of the substrate including the projecting section, the mask layer is formed with an opening for partially forming the first heat insulating layer at an apex of the projecting section, and the apex of the projecting section is exposed from the opening.