Abstract: An ink jet print head comprises a substrate formed with a heating resistor, an ink path defining member for defining an ink supply path, and a orifice plate, and in the orifice plate, there is formed an ink outlet at the position opposing the heating resistor. Further, a heating zone surrounding the heating resistor is formed at the position corresponding to the heating resistor of the ink supply path. The channel resistance of the ink supply path is set so that a relationship is established between a quantity q of the discharged ink drop, a sectional area A of the ink outlet, and a maximal projection h that a meniscus of the ink has when it projects from the ink outlet after it has restored the exit level from a retreat position it had after the drop of the ink had been discharged, such that 0<h<0.3 q/A. Consequently, there is obtained a high-speed printing of high quality without dispersion.

Abstract: An ink jet print head comprises a substrate formed with a heating resistor, an ink path defining member for defining an ink supply path, and a orifice plate, and in the orifice plate, there is formed an ink outlet at the position opposing the heating resistor. Further, a heating zone surrounding the heating resistor is formed at the position corresponding to the heating resistor of the ink supply path. The channel resistance of the ink supply path is set so that a relationship is established between a quantity q of the discharged ink drop, a sectional area A of the ink outlet, and a maximal projection h that a meniscus of the ink has when it projects from the ink outlet after it has restored the exit level from a retreat position it had after the drop of the ink had been discharged, such that 0<h<0.3 q/A. Consequently, there is obtained a high-speed printing of high quality without dispersion.

Abstract: An ink jet print head comprises a substrate formed with a heating resistor, an ink path defining member for defining an ink supply path, and a orifice plate, and in the orifice plate, there is formed an ink outlet at the position opposing the heating resistor. Further, a heating zone surrounding the heating resistor is formed at the position corresponding to the heating resistor of the ink supply path. The channel resistance of the ink supply path is set so that a relationship is established between a quantity q of the discharged ink drop, a sectional area A of the ink outlet, and a maximal projection h that a meniscus of the ink has when it projects from the ink outlet after it has restored the exit level from a retreat position it had after the drop of the ink had been discharged, such that 0<h<0.3q/A. Consequently, there is obtained a high-speed printing of high quality without dispersion.

Abstract: Method and apparatus for non-destructive inspection of flaws in metal materials include exciting coils centered on a longitudinal axis of a cylindrical or columnar metallic material to be examined being arranged to surround the examinee material. A multiphase alternating current of such a relatively low frequency as to cause the exciting coils to generate a rotating magnetic field which rotates about the longitudinal axis of the examinee material is superimposed with a high frequency alternating current having an inspection frequency selected on the basis of the necessary sensitivity for detection of surface flaws of the examinee material. The composite multiphase current is applied to the exciting coils so that an electromagnetic effect induced in the surface of the examinee material by the high frequency alternating current is rotated for shifting circumferentially about the examinee material along with the rotating magnetic field.