Abstract: An ink nozzle plate has ink discharge channels for discharging ink, and an air nozzle plate has air discharge channels facing the ink discharge channels for discharging air to jet the ink. A power source produces an electric field through the ink at the ink discharge channels, thereby extending the ink meniscus, and the ink is jetted from the air discharge channels by air-flow and the electric field. A heating means increases the temperature of the air nozzle plate, thereby vaporizing water adsorbed in the air discharge channels and stabilizing the ink jet volume.

Abstract: A multi-nozzle type ink jet recording apparatus arranged so as to eject ink from each of a plurality of ink nozzles toward a writing surface by means of an electric field established due to an ink ejecting signal applied to each of the ink nozzles. The ink jet recording apparatus includes a circuit for generating a density information signal indicative of a recording density at every ink nozzle and a control unit being responsive to the density information signal and having a plurality of memories. Each of the plurality of memories stores a density-to-signal characteristic being predetermined to correspond to one or more of the ink nozzle and the density-signal characteristic represents the relation between the recording density and the ink ejecting signal indicative of an ink ejecting amount ejected from each of the ink nozzles.

Abstract: An ink jet recording apparatus with an ink jet printing head is disclosed. The ink jet printing head has first and second electrodes for ejecting ink toward writing paper by means of an electric field established between the first and second electrodes, the first electrode being disposed in opposed relation to the writing paper. The writing paper is placed on a cylindrical drum which is provided so as to be in opposed relation to the ink jet printing head and moved with respect to the ink jet printing head. Also included in the ink jet recording apparatus is a third electrode which is provided on the outer surface of the cylindrical drum in opposed relation to the ink jet printing head. The third electrode is controlled so that the potential thereof is equal to or higher than that of the ink jet printing head.

Abstract: A drive circuit suitable for producing a high voltage drive output signal has an output stage formed of a P-channel MOS FET (4) and an N-channel MOS FET (5) connected for push-pull operation. The circuit is configured such that even with a supply voltage applied to the output stage which is higher than the ON-state withstand voltage of the MOS FETs, this value of voltage is prevented from being applied to a MOS FET which is in the ON stage, i.e. by providing voltage-dropping resistors (R.sub.1, R.sub.2) connected between the drain electrodes of the MOS FETs (4, 5) or utilizing a circuit which prevents each MOS FET from entering the ON state until after the other MOS FET has entered the OFF state.

Abstract: Disclosed is a method for operation of an ink jet printing head of the type wherein printing ink is discharged from a plurality of ink nozzles toward a writing surface by the aid of an electric field established between a plurality of control electrodes associated with the ink nozzles and a common electrode in opposed relation to the control electrodes. In response to a picture element signal for controlling the discharge of ink from the ink nozzles, a control pulse is generated and applied to each of the control electrodes, while a pulse bias is generated and provided to the common electrode. The pulse bias is supplied thereto only in the presence of the control pulse. The minimum width of the control pulse is established to be greater than 1/fp and smaller than 2/fp where fp is the frequency of the picture element signal.