Ultrasonic printing apparatus and method in which the phases of the ultrasonic oscillators are controlled to prevent unwanted phase cancellations

An ultrasonic printing method wherein an ultrasonic wave to be irradiated as a converging ultrasonic wave upon ink is emitted to discharge the ink in the proximity of a converging point of the converging ultrasonic wave as an ink drop to stick to a recording medium to form a dot on the recording medium in order to perform recording on the recording medium, comprising the step of:

• varying a frequency of the converging ultrasonic wave with respect to time within a predetermined frequency range centered at a standard resonance frequency.

An ultrasonic printing apparatus, comprising:

• at least one ultrasonic oscillator for being driven to emit an ultrasonic wave to be irradiated as a converging ultrasonic wave upon ink to discharge the ink in the proximity of a converging point of the converging ultrasonic wave as an ink drop to stick to a recording medium to form a dot on the recording medium in order to perform recording on the recording medium:
• and
• a control circuit for controlling said ultrasonic oscillator so that a frequency of the converging ultrasonic wave to be emitted from said ultrasonic oscillator is varied with respect to time within a predetermined frequency range centered at a standard resonance frequency.

An ultrasonic printing method wherein an ultrasonic wave to be irradiated as a converging ultrasonic wave upon ink is emitted to discharge the ink in the proximity of a converging point of the converging ultrasonic wave as an ink drop to stick to a recording medium to form a dot on the recording medium in order to perform recording on the recording medium, comprising the step of:

• emitting, after discharging of each ink drop, at a same ink drop discharging position as that in the last ink drop discharging operation when a position of a level of the ink becomes lower than a position of the ink level in a stable condition of the ink level due to residual oscillations of the ink level, a converging ultrasonic wave having energy insufficient to discharge an ink drop to the ink.

An ultrasonic printing method wherein an ultrasonic wave to be irradiated as a converging ultrasonic wave upon ink is emitted to discharge the ink in the proximity of a converging point of the converging ultrasonic wave as an ink drop to stick to a recording medium to form a dot on the recording medium in order to perform recording on the recording medium, comprising the step of:

• emitting, when a next ink drop is to be discharged, immediately after discharging of an ink drop, successively for the same dot, a converging ultrasonic wave having energy based on a position of a level of the ink which is moved by residual oscillations of the ink level to the ink.

An ultrasonic printing apparatus, comprising:

• at least one ultrasonic oscillator for being driven to emit an ultrasonic wave to be irradiated as converging ultrasonic wave upon ink to discharge the ink in the proximity of a converging point of the converging ultrasonic wave as an ink drop to stick to a recording medium to form a dot on the recording medium in order to perform recording on the recording medium;
• and
• a control circuit for controlling a driving condition of said ultrasonic oscillator so that said ultrasonic oscillator emits, after discharging of each ink drop, at a same ink drop discharging position as that in the last ink drop discharging operation when a position of a level of the ink becomes lower than a position of the ink level in a stable condition of the ink level due to residual oscillations of the ink level, a converging ultrasonic wave having energy insufficient to discharge an ink drop to the ink.

An ultrasonic printing apparatus, comprising:

• at least one ultrasonic oscillator for being driven to emit an ultrasonic wave to be irradiated as a converging ultrasonic wave upon ink to discharge the ink in the proximity of a converging point of the converging ultrasonic wave as an ink drop to stick to a recording medium to form a dot on the recording medium in order to perform recording on the recording medium;
• and
• a control circuit for controlling a driving condition of said ultrasonic oscillator so that said ultrasonic oscillator emits, when a next ink drop is to be discharged, immediately after discharging of an ink drop, successively for the same dot, a converging ultrasonic wave having energy based on a position of a level of the ink which is moved by residual oscillations of the ink level to the ink.

A method of forming an acoustic lens, which converges an acoustic wave having been transmitted in an acoustic medium to a predetermined converging point, on the acoustic medium, comprising the step of:

• irradiating an excimer laser beam upon the acoustic medium to form the acoustic lens on the acoustic medium.