Ink-jet head driving circuit

摘要

An ink-jet head driver comprises: a pressure chamber filled with a recording liquid; a piezo-electric element as electrical/mechanical transducing means for enlarging the capacity of the pressure chamber at a first stage and contracting it in a second stage into the state before enlargement, thereby emitting the recording liquid; and a device for adjusting the time interval between the first and second stages to adjust the emitting velocity. The capacity of the pressure chamber is changed due to charge and discharge by a charging/discharging circuit, and charge/discharge time constants of this circuit are selectively controlled by a control unit. According to this driver, mixture of air into recording liquid in the ink-jet head when the piezo-electric element is expanded is prevented, and a variable range of a dot diameter of the recording liquid droplet can be extended, thereby improving recording quality.