초록 ▼

Ink is fed into an ink chamber in an ink ejection head. An ejection orifice communicates with the ink chamber. An electrostrictive plate defines a surface of the ink chamber and is strained to decrease the volume of the ink chamber when an electrical pulse is applied thereto to cause ink to be eject

Ink is fed into an ink chamber in an ink ejection head. An ejection orifice communicates with the ink chamber. An electrostrictive plate defines a surface of the ink chamber and is strained to decrease the volume of the ink chamber when an electrical pulse is applied thereto to cause ink to be ejected through the orifice. The apparatus is inoperative if there is no ink in the ink chamber or there are air bubbles in the ink in the ink chamber. In such a case the voltage across the electrostrictive plate has an oscillating component, the oscillating component being damped out when the ink chamber is completely filled with ink. A sensor is provided to detect the oscillating component and generate a signal indicating said detection. Circuit means are provided to increase the magnitude of the pulse when the oscillating component has a magnitude indicating that the apparatus is not inoperative but some bubbles are present in the chamber. The increased pulse magnitude serves to maintain the ink ejection at the desired level.

대표청구항 ▼

Ink ejection apparatus, comprising: an ink ejection head defining an ink chamber and an ejection orifice communicating with the ink chamber; an electrostrictive member defining part of the ink chamber; a pulse generator to feed a pulse to the electrostrictive member to cause reduction of a volume of

Ink ejection apparatus, comprising: an ink ejection head defining an ink chamber and an ejection orifice communicating with the ink chamber; an electrostrictive member defining part of the ink chamber; a pulse generator to feed a pulse to the electrostrictive member to cause reduction of a volume of the ink chamber; and sensor means to detect oscillation of the electrostrictive member during a duration of the pulse and produce an electrical signal in response thereto that indicates whether there is sufficient ink in the ink chamber.