Abstract: A process for producing a liquid jet recording head, comprising the steps of: providing a substrate for a liquid jet recording head, which is provided with a heat generating resistor; forming a thermoplastic resin layer capable of being solubilized on the substrate; subjecting the thermoplastic resin layer on the substrate to patterning treatment to form an ink pathway pattern in a state that the heat generating resistor is positioned at the bottom of the ink pathway pattern while being covered by the ink pathway pattern; subjecting the ink pathway pattern to heat treatment at a higher temperature than the melting point of the thermoplastic resin layer constituting the ink pathway pattern to round corners of the ink pathway pattern into a rounded ink pathway pattern; forming a resin coat layer on the substrate having the rounded ink pathway pattern thereon; forming an ink discharge outlet at a portion of the resin coat layer which is situated right above the heat generating resistor; and eluting the rounded i

Abstract: A method of manufacturing an ink jet recording head, having the steps of forming an ink flow path pattern on a substrate with the use of a dissoluble resin, the substrate having ink ejection pressure generating elements thereon, forming on the ink flow path pattern a coating resin layer, which will serve as ink flow path walls, by dissolving in a solvent a coating resin containing an epoxy resin which is solid at ordinary temperatures, and then solvent-coating the solution on the ink flow path pattern, forming ink ejection outlets in the coating resin layer above the ink ejection pressure generating elements, and dissolving the ink flow path pattern.