Thermal head with protective layer
AssigneeRohm Co., Ltd.
InventorTeruhisa Sako
Life of this patent
Estimating the term…
Abstract
A thermal head (A) according to the present invention includes a substrate (1) on which a heat-producing resistor (5), a common electrode (3) and individual electrodes (4) for energizing the heat-producing resistor (5), and a protective layer (6) having a double-layer structure and formed on the heat-producing resistor (5) to cover at least the heat-producing resistor are provided. A second protective layer (6B) constituting the upper layer of the protective layer (6) is conductive, and a first protective layer (6A) constituting the lower layer of the protective layer (6) has thickness (t1) which is not less than three times the thickness (t2) of the second protective layer (6B).
Claims16
A thermal head comprising a substrate on which a heat-producing resistor, an electrode for energizing the heat-producing resistor and a protective layer having a double-layer structure and covering at least the heat-producing resistor are provided;
- wherein a second protective layer constituting an upper layer of the protective layer is conductive and formed by printing and baking glass paste, wherein a first protective layer constituting a lower layer of the protective layer is formed by printing and baking glass paste and has a thickness of not less than three times a thickness of the second protective layer, and wherein a softening temperature of the second protective layer is lower than a softening temperature of the first protective layer, the second protective layer being porous.
A thermal head comprising a substrate on which a heat-producing resistor, an electrode for energizing the heat-producing resistor and a protective layer having a double-layer structure and covering at least the heat-producing resistor are provided, the protective layer being made up of a first protective layer as a lower layer and a second protective layer as an upper layer;
- wherein the first protective layer is made of amorphous glass in a manner such that bubbles contained in the amorphous glass are caused to disappear, and
- wherein the second protective layer is made of crystallized glass in a manner such that the second protective layer is porous and has an irregular obverse surface.
Dependencies are inferred from the claim text.