Abstract: An electrostatic inkjet apparatus includes a plurality of ejection electrodes and a plurality of control electrodes. The ejection electrodes are arranged in an ink chamber for containing ink including particulate matter with protruding from a front end of the ink chamber. The control electrodes are arranged in the ink chamber such that each of the ejection electrodes is placed between two adjacent control electrodes. A voltage controller applies a control voltage to two control electrodes adjacent to a selected ejection electrode which is in a floating state and thereby a potential of the selected ejection electrode is changed to an ejection level.

Abstract: The invention relates to an ink-jet printer which uses an ink containing fine solid particles of a pigment suspended in a carrier liquid. The print head of the printer has an ink ejection orifice at one end of an ink chamber, and the ink chamber is provided with a first electrode to which a first DC voltage is applied for concentrating the pigment particles in the vicinity of the orifice by electrophoresis and a second electrode to which a second DC voltage in pulse form is applied for ejecting an agglomeration of the pigment particles together with a small amount of carrier liquid from the orifice. In the printer, the length of waiting time, which elapses from the decay of a pulse of the second voltage, is checked.

Abstract: The invention relates to an ink-jet printer using an ink containing fine solid particles of a pigment suspended in a carrier liquid. The print head of the printer has an ink ejection orifice at one end of an ink chamber, and the ink chamber is provided with a first electrode to which a DC voltage is applied for concentrating the pigment particles in the ink in the vicinity of the orifice by electrophoresis and a second electrode to which a DC voltage in pulse form is applied for ejecting an agglomeration or several agglomerations of the concentrated pigment particles together with a small amount of carrier liquid from the orifice. The rate of migration of the pigment particles depends on the temperature of the ink. For stable ejection of agglomerations of pigment particles, a temperature sensor is disposed in the ink chamber, and the voltage applied to the first electrode is varied according to the detected temperature of the ink.

Abstract: An ink jet type head has a plurality of ink ejection electrodes in a form of parallel strips formed on a base. The ink ejection electrodes include first ejection electrode and second ejection electrodes provided adjacent to two sides of the first ejection electrode. There is provided a voltage driving unit for applying an ejection voltage for ink ejection to the first ejection electrode. In the voltage driving unit, the ejection voltage to cause the ink to be ejected is applied to the first ejection electrode and an auxiliary voltage ineffective to cause the ink to be ejected is applied to the second ejection electrodes. This enables the reduction of potential differences between the first and second ejection electrodes, thus suppressing movement of color particles of the ink between them.