Abstract: A valve for an ink jet printer is made by vacuum depositing, sputtering, and plating various layers of metal on a glass substrate. A photoresist and etch technique is used to form a window area in one of the layers and a fine slit for forming a tongue in another of the layers within the window area. When the window area is formed, an elongated projection remains in the window area to prevent the tongue from bending in one direction while enabling it to bend in an opposite direction. This way ink pressure on one side opens the valve and pressure on the opposite side choses the valve.

Abstract: A thermal printing head which effects printing on thermally sensitive paper with Joule's heat generated by passing a current through a thick-film resistor is featured by the surface configuration of the thick-film resistor. In a cross-section perpendicular to the direction of the current passing through the resistor, the resistor is formed in such shape that the center portion is lower than the opposite edge portions. Owing to such concave top surface, despite of the fact that the heating resistor is a thick-film resistor, printing of high quality that is compatible to printing quality by a thin-film resistor can be accomplished. A practically useful thermal head having the resistors with the concave top surface can be realized through the photo-resist pattern technique combined with the screen printing technique.