Inkjet print head and method therefor
View Patent ↗An inkjet print head is fabricated by forming an electrode and two protection film layers composed of an inorganic insulating film and an organic insulating film over the electrode within a groove of a piezoelectric member, adhering a top board to the piezoelectric member covering the groove to form a pressure chamber, adhering a polyimide plate to cover the groove, and then forming a nozzle in the polyimide plate by the excimer laser processing aligning to the pressure chamber. The excimer laser light penetrates the polyimide plate to form a nozzle is then emitted on the organic insulating film. Consequently, part of the organic insulating film is damaged by the laser light. To prevent this damage, the thickness of the inorganic insulating film in the part to which the excimer laser light is emitted is prepared to be 0.5 μm or more.
1. An inkjet print head having a plurality of grooves each comprising a pressure chamber, a nozzle plate comprising a plurality of nozzles formed by a laser process, the nozzle plate covering an opening of each of the pressure chambers and each pressure chamber communicating with a respective nozzle, a plurality of pressure generating parts each causing ink within the respective pressure chamber to be ejected from the associated nozzle, a top board covering the grooves so as to form the individual pressure chambers, an ink supplying port supplying ink to the pressure chambers, and a plurality of electrodes each formed on an internal surface of each of the respective pressure chambers for supplying a drive pulse to the respective pressure generating parts, the inkjet print head comprising:
a first protecting film comprised of an inorganic insulating material having a predetermined thickness partially formed on each electrode; and
a second protecting film comprised of an organic insulating material formed on the first protecting film and on a portion of the electrode which is not covered by the first protecting film, the second protecting film having a plurality of laser-damaged holes in which the organic insulating material has been partially removed when the nozzles were formed by the laser process, the laser-damaged holes exposing a portion of the first protecting film,
wherein the first protecting film has an area larger than the laser damaged hole.
2. The inkjet print head according to claim 1 , wherein a position of the laser-damaged hole is off a center of the pressure chamber towards the nozzle in an ink flow direction within the pressure chamber.
3. The inkjet print head according to claim 1 , wherein the first protecting film is comprised of a material selected from the group consisting of Al 2 O 3 , SiO 2 , ZnO, MgO, ZrO 2 , Ta 2 O 5 , Cr 2 O 3 , TiO 2 , Y 2 O 3 , YBCO, Mullite (Al 2 O 3 SiO 2 ), SrTiO 3 , Si 3 N 4 , ZrN, AlN, and Fe 3 O 4 .
4. The inkjet print head according to claim 1 , wherein the second protecting film is comprised of a material selected from the group consisting of Parylene-C, Parylene-N, Parylene-D, Parylene-HR, Parylene-SR, and polyimide.
5. The inkjet print head according to claim 1 , wherein the first protecting film is formed by one of: digital sputtering method, PLD method, AP-CVD method, PE-CVD method, and ALD (Atomic Layer Deposition) method.