Ink jet recording head utilizing a vibration plate having diaphragm portions and thick wall portions

An ink jet recording head comprising:

• a substrate unit formed by laminating and fixing a flow path forming plate, a nozzle plate, and a vibration plate, said flow path forming plate having at least one pressure producing chamber extending between at least two opposing chamber sides, at least one ink supply inlet, and a common ink chamber;
• said nozzle plate having at least one nozzle opening communicating with the pressure producing chamber;
• said vibration plate having at least one diaphragm portion, the diaphragm portion being resiliently deformable in response to a displacement force applied to the diaphragm portion;
• and said substrate unit being fixed to a base housing a piezoelectric vibration element,
• wherein said vibration plate has a frame-like thick wall portion formed close to the chamber sides of the pressure producing chamber and has a further thick wall portion that is formed over the diaphragm portion;
• the frame-like thick wall portion and the further thick wall portion are thicker than the diaphragm portion;
• the frame-like thick wall portion is elongated toward the piezoelectric vibration element at least at a surface of the frame-like thick wall portion facing the chamber sides and attached to the diaphragm portion so that the surface overhangs the chamber sides, to form elongated portions;
• the further thick wall portion is interposed between the diaphragm portion and the piezoelectric vibration element;
• and a region of the frame-like thick wall portion, including the elongated portions, serves as a region for bonding said substrate unit to the base.