Abstract: A circuit for driving an ink-jet head comprising a common driving waveform generation circuit 11 for generating a driving voltage signal, an analog/digital converter circuit 12 for converting the driving voltage signal into driving waveform data, a gradation data separation/accumulation circuit 13 for separating printing gradation data contained in printing data therefrom, accumulating therein the separated printing gradation data temporarily, and outputting the separated printing gradation data at a predetermined timing, a comparator circuit 14 for comparing the printing gradation data with the driving waveform data and outputting a comparison signal.

Abstract: In a piezoelectric type ink jet head, a plurality of pressure chambers are separated into n groups each having dummy pressure chambers at opposite ends. An increased spacing between ejection nozzles resulting from the dummy pressure chambers is compensated for by inclining the nozzle openings within each of the groups. The ink jet head is driven in a time sharing manner.

Abstract: An ink jet head is disclosed for use with a drop-on demand type printer, and includes an insulating base, a plurality of elongated barriers projecting upwardly from the base so as to form a plurality of slots between the barriers, a plurality of nozzle holes communicating with the slots, and electrodes formed on the side walls of the elongated barriers. Voltage can be applied to the various barriers through the electrodes in order to cause deflection of the barriers and a corresponding reduction in the cross-sectional area of selected slots, so as to force ink contained in the slots to be jetted through the nozzle holes. In order to provide a uniform ink jet intensity from the outermost slots relative to the inner slots, dummy slots can be formed outwardly of the outermost active slots by providing dummy barriers outwardly of the outermost active barriers. In addition, the nozzle holes are formed in a nozzle plate. The nozzle plate can either be mounted against the ends of the slots, or atop the base.

Abstract: An ink-jet printing head comprises a laminated unit integrally formed as a sintered ceramic product and including a bottom insulating plate element, a top insulating plate element, and a piezoelectric plate element between the bottom and top insulating plate element, the laminated unit having a pressure chamber formed at the piezoelectric plate element fillable with an ink, the piezoelectric plate element having electrode layers formed on opposite surfaces thereof surrounding the pressure chamber, the laminated unit also being provided with an orifice in communication with the pressure chamber. The piezoelectric plate element is constituted such that its thickness is reduced upon applying a drive pulse voltage thereto, resulting in a decrease of the pressure chamber volume, whereby an ink-jet drop is ejected from the orifice.

Abstract: A device for feeding a magnetic head used in a magnetic disc apparatus, wherein phase currents of the pulse motor are controlled by sensing the signals that are produced in proportion to off-track quantity of the head or by receiving signals that results from an error contained in the reproduced signals, in order to bring the head to a proper position.

Abstract: The operating speed of an electronic timepiece, whose electro-optical indicator is excited by an oscillator with a frequency harmonically related to its stepping rate, is determined by an electrostatic sensor including a monitoring plate capacitively coupled to an electrode of the indicator. The output of the sensor is a bipolar pulse train developed across a resistor defining a differentiation circuit of small time constant with the condenser formed by the monitoring plate and the electrode, the capacitance of this condenser being on the order of 1 pf or less so that the controlling oscillator is not significantly loaded by the presence of the sensor.