Ink jet head for high speed printing and method for it's fabrication

Claim 1

An ink jet head which comprises: an ink chamber (31) including as part of its peripheral wall a nozzle plate (10) having a nozzle opening (11), and a substrate (7) opposed to the nozzle plate (10); and a pressure generating member (20) provided in the ink chamber (31) and opposed to the nozzle plate (10), wherein the pressure generating member (20) is deformed to generate a pressure within the ink chamber (31), so that ink liquid in the ink chamber (31) is discharged out of the ink chamber (31) through the nozzle opening (11), the pressure generating member (20) comprising: a buckling member (1) which is formed into a generally plate shape, where portions forming both ends in at least one direction out of a peripheral portion of the buckling member (1) are attached to the substrate (7), and which buckling member (1) is switchable between a no-displacement state in which the buckling member (1) undergoes substantially no thermal stress, and a buckling state in which the buckling member (1) is buckled through thermal expansion; and a heater layer (3) which is provided along one surface of the buckling member (1) and which generates heat through electrical energization.

Claim 25

A method for fabricating an ink jet head which comprises: an ink chamber (31) including as part of its peripheral wall a nozzle plate (10) having a nozzle opening (11), and a substrate (7) opposed to the nozzle plate (10); and a pressure generating member (20) provided in the ink chamber (31) and opposed to the nozzle plate (10), wherein the pressure generating member (20) comprises a plate-shaped buckling member (1), a heater layer (3) provided on one side of the buckling member (1) on which the substrate (7) is provided, and a diaphragm (5) provided on one side of the buckling member (1) on which the nozzle plate (10) is provided, the method comprising the steps of: forming a first sacrifice layer (120) having a pattern occupying a specified closed area on a surface of the substrate (7); forming a first insulating layer (2) composed of a material that can be etched selectively with the first sacrifice layer (120) in such a manner that the first insulating layer (2) covers the first sacrifice layer (120); forming on the first insulating layer (2) a heater layer (3) having a pattern passing through an area occupied by the first sacrifice layer (120); forming a second insulating layer (4) composed of a material that can be etched selectively with the first sacrifice layer (120) in such a manner that the second insulating layer (4) covers the above-formed layers (2, 3); forming slits (40) along both sides of the pattern of the heater layer (3) in such a manner that the slits (40) extend from a front surface of the second insulating layer (4) to a front surface of the first sacrifice layer (120); burying interiors of the slits (40) by applying resist onto the substrate (7) and by performing photolithography, and forming a resist wall (190) that protrudes from the front surface of the second insulating layer (4) by a specified height with its width kept equal to that of the slits (40); forming on the second insulating layer (4) a first metal layer (200) for constituting the buckling member (1), by a plating process into a specified thickness which does not exceed the height of the resist wall (190); forming a second sacrifice layer (210) composed of a material that can be etched selectively with the first metal layer (200), on a closed area generally corresponding to the first sacrifice layer (120) in such a manner that the second sacrifice layer (210) covers a specified portion of a front surface of the first metal layer (200) as well as the slits (40); forming a second metal layer (220) serving for constituting the diaphragm (5) and composed of a material that can be etched selectively with the second sacrifice layer (210), all over so that the second metal layer (220) covers the above-formed layers (200, 210) on the surface of the substrate (7); boring a hole (16) reaching the first sacrifice layer (120) on the front surface side of the substrate (7) by performing etching from a rear surface side of the substrate (7), etching and thereby removing the first sacrifice layer (120) through the hole (16) selectively with the first and second insulating layers (2, 4), and subsequently removing the resist wall (190), and further etching and thereby removing the second sacrifice layer (210) through the slits (40) generated by removing the resist wall (190) selectively with the first and second metal layers (200, 220); and forming the diaphragm (5) having a specified configuration by patterning the second metal layer (220).