Patent ID: 7907158

Claim:
A thermal head comprising: a glass layer having a protruding section configured as a substantially circular arc shape and formed on one surface and a concave groove section formed on the other surface facing the protruding section, the concave groove section being defined by a ceiling face and a pair of wall faces disposed apart from each other and depending from the ceiling face; a heat generation resistor provided on the protruding section; and a pair of electrodes provided to both sides of the heat generation resistor, wherein a part of the heat generation resistor exposed between the pair of electrodes is defined as a heat generation section, the protruding section has a pair of side circular arc-shaped portions and a central circular arc-shaped portion disposed between the pair of side circular arc-shaped portions, each one of the pair of side arc-shaped portions having a smaller curvature radius than a curvature radius of the central circular arc-shaped portion, a width of the ceiling face is one of equal to and larger than a length of the heat generation section, and the pair of wall faces extend either perpendicularly from the ceiling face or obtusely relative to the ceiling face.