HALFTONE IMAGE DEVICE AND ITS DRIVING CIRCUIT

摘要

The invention makes it possible to drive a halftone image device and achieve high halftone reproduction by allowing at least one of the leading and trailing edges of a pulse width- modulated signal applied to a recording head, or forming amplitude- and width-modulated pulses, respectively, as driving pulses for placing one dot under halftone control, and changing a pulse width change of pulse width modulation in a stepwise manner, using the pulse width of the amplitude- modulated pulse as a unit pulse width. The invention intends to achieve high-voltage and high- speed pulse output and low power consumption by converting input data such as halftone image data to a voltage signal, superposing pulse voltages of opposite polarities and applying the resulting signal to a switching circuit constituting an output state in the form of a switching signal, and also makes it possible to achieve high speed and high-voltage driving by connecting at least one of equivalent two-terminal elements in series to at least one of the respective driving elements of a complementary FET driving circuit, said equivalent two- terminal elements are each put on with a current of a certain or higher value passing therethrough to show constant-voltage characteristics and put off with a current of a certain or lower value passing therethrough to become a constant resistance.