PURPOSE: To provide an ink jet head formed in integral manner with a nozzle unit and a holder by hydrophobic thermoplastic resin injection molding with inexpensive cost without ink clogging but with preferable ink injection property.
CONSTITUTION: Thermoplastic resin (e.g., polybutylene terephthalate, polyvinilydene fluoride) having strong hydrophobic property and excellent chemical resistance is injection molded, thereby forming an ink jet head 10 which is composed of a holder 11 gaving an ink pressurizing chamber 12 and a nozzle unit 13 having an ink jet fine hole 14. A mold 20 for the above injection molding has an upper die 21 having a round rod 22 for forming a pressurizing chamber and a pin 23 for forming a fine hole 14, and a lower die 20 having a hole 24 engaged with the pin 23 (numeral 25 is a spool and 26 a ring gate).
KUROKAWA TAKASHI
NARA SHIGEO
