Patent ID: 7665831

Claim:
An image forming apparatus in which a plurality of ink chambers filled with ink are aligned, said ink chambers being expanded or contracted and ink being discharged from nozzles of the ink chambers onto a recording medium, by applying a voltage to piezoelectric elements provided on an outer perimeter or an outer side of the ink chambers, each piezoelectric element including first and second electrodes, wherein said piezoelectric elements are arranged in a plane substantially parallel to a nozzle surface in which said nozzles are formed; a lower face of a common vibration plate constitutes a ceiling of the plurality of ink chambers; the piezoelectric elements are constituted of a common plate-shaped piezoelectric member that is provided over the common vibration plate; the piezoelectric elements deform in a d 31 mode to expand or contract the ink chambers; a common electrode, corresponding to the first electrode, is provided on a bottom surface of the common plate-shaped piezoelectric member; and individual electrodes, corresponding to the second electrodes, are provided on an upper surface opposite to the bottom surface of the common plate-shaped piezoelectric member; shorting devices which short said piezoelectric elements are provided, the shorting devices include shorting switches which make and break connection to shorting lines for shorting the piezoelectric elements, and drive switches are provided, the drive switches make and break connection to lines for applying the voltage to the piezoelectric elements, wherein when a drive switch connects a piezoelectric element to the line for applying voltage to the piezoelectric element, a shorting switch disconnects the piezoelectric element from the shorting lines, when a shorting switch connects the piezoelectric element to the shorting lines, the drive switch disconnects the piezoelectric element from the line for applying voltage, fixed electrodes are respectively disposed above partitions dividing the plurality of adjacently positioned pressure chambers and on the common plate-shaped piezoelectric member, and a shorting circuit for shorting the first electrode and each of the fixed electrodes is provided.