Claims
- 1. A method of making a thin film thermal printhead comprising the steps of:
- glazing a surface of a head substrate, the head substrate having a first longitudinal edge and a second longitudinal edge;
- forming a patterned resistor layer as a thin film on the glazed surface of the head substrate to provide a strip of heating dots extending along the first longitudinal edge of the head substrate; and
- forming a patterned conductor layer on the resistor layer for selectively supplying power to the heating dots;
- wherein the glazing step comprising applying a glaze layer with a uniform thickness on the surface of the head substrate to extend from the first longitudinal edge toward second longitudinal edge of the head substrate, baking the glaze layer, performing partial material removal of the glaze layer adjacent to the first longitudinal edge of the head substrate, and again baking the glaze layer, whereby the glaze layer is made to have a normal first surface portion and a rounded marginal surface portion continuous with the normal flat surface portion, the rounded marginal surface portion extending along the first longitudinal edge of the head substrate and progressively approaching the head substrate toward the first longitudinal edge;
- wherein the heating dots strip is located at least partially at the rounded marginal surface of the glaze layer and
- wherein the partial material removal of the glaze layer is performed to form a non-inclined stepped marginal portion adjacent to the first longitudinal edge of the head substrate, the stepped marginal portion being later deformed by subsequent baking to provide said rounded marginal surface portion of the glaze layer.
- 2. The method according to claim 1, wherein the partial material removal of the glaze layer is performed by abrasive blasting.
- 3. The method according to claim 2, wherein the abrasive blasting is conducted in a direction perpendicular to the glaze layer.
Priority Claims (2)
Number |
Date |
Country |
Kind |
5-167066 |
Jul 1993 |
JPX |
|
5-199782 |
Aug 1993 |
JPX |
|
Parent Case Info
This application is a division of application Ser. No. 08/254,512 filed Jun. 6, 1994, now abandoned.
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4651168 |
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5367320 |
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|
Foreign Referenced Citations (1)
Number |
Date |
Country |
0398582 |
Nov 1990 |
EPX |
Divisions (1)
|
Number |
Date |
Country |
Parent |
254512 |
Jun 1994 |
|