| 摘要 |
PURPOSE:To increase piezo driving frequency by alternately changing over a first drive driving a first piezo installed in response to a first pressure chamber connected to a nozzle, from which ink is injected, and a second drive driving a second piezo mounted in response to a second pressure chamber connected to the same nozzle. CONSTITUTION:A piezo driving signal PD is output to a first drive 7 from a piezo driving signal generator 9 by a changeover device 6. The piezo charging Tr 23 of the first drive 7 is turned ON, charging currents are made to flow through a first piezo 3 from a piezo power supply 10 through a piezo charging resistor 21, and a piezo is displaced. The volume of a first pressure chamber is changed, and ink is discharged from a nozzle 1. When H is brought to L in the piezo driving signal PD, the piezo charging Tr 23 is turned OFF, a piezo discharging Tr 24 is turned ON, piezo discharge currents are made to flow through a piezo discharging resistor 22 from the first piezo 3, and the piezo is displaced. The volume of the first pressure chamber intends to be returned to an original state, and the first pressure chamber is supplied with ink. When the first drive 7 is changed over to a second drive 8, the same operation as the first drive is conducted in the drive 8. |
