Device and method for driving jetting head

1. A head driving device, which drives a plurality of pressure generating elements for generating pressure fluctuation in a jetted object contained in each of associated pressure chambers formed in a jetting head of a jetting apparatus to eject the jetted object from each of nozzles communicating with the associated pressure chambers, the head driving device comprising:

a head driver, which generates a drive signal which is selectively applied to at least one of the pressure generating elements to be driven;

a bias potential provider, which applies a bias potential for reducing electrical potential difference between electrodes of each of the pressure generating elements to respective ground side electrodes of the pressure generating elements;

a controller, which controls the head driver and the bias potential provider at different timing; and

a capacitor, provided with a first terminal which is electrically connected to the respective groundside electrodes of the pressure generating elements and a second terminal which is grounded.

2. The head driving device as set forth in claim 1 , wherein the controller supplies a first control signal to the head driver;

wherein the controller supplies a second control signal to the bias potential provider; and

wherein the first control signal and the second control signal are supplied at different timing.

3. The head driving device as set forth in claim 2 , wherein the drive signal is selectively applied to the at least one of the pressure generating elements to be driven in accordance with the first control signal; and

wherein the bias potential is applied to the respective ground-side electrodes of the pressure generating elements in accordance with the second control signal.

4. The head driving device as set forth in claim 1 , further comprising a control resistor which electrically connects the first terminal of the capacitor and the bias potential provider.

5. The head driving device as set forth in claim 1 , wherein the capacitor has capacitance which is sufficiently greater than a total electrostatic capacitance of the pressure generating elements.

6. A head driving device, which drives a plurality of pressure generating elements for generating pressure fluctuation in a jetted object contained in each of associated pressure chambers formed in a jetting head of a jetting apparatus to eject the jetted object from each of nozzles communicating with the associated pressure chambers, the head driving device comprising:

a head driver, which generates a drive signal which is selectively applied to at least one of the pressure generating elements to be driven;

a bias potential provider, which applies a bias potential to respective groundside electrodes of the pressure generating elements;

a first digital/analog converter, which converts a first digital signal inputted to the head driver into a first analog signal; and

a second digital/analog converter, which converts a second digital signal inputted to the bias potential provider into a second analog signal,

wherein the drive signal is selectively applied to the at least one of the pressure generating elements in accordance with the first analog signal, and

wherein the bias potential is applied to the respective ground-side electrodes of the pressure generating elements in accordance with the second analog signal.

7. The head driving device as set forth in claim 6 , wherein the bias potential is a reference potential of the drive signal.

8. The head driving device as set forth in claim 6 , further comprising:

a capacitor, having capacitance which is sufficiently greater than a total electrostatic capacitance of the pressure generating elements, the capacitor provided with a first terminal which is electrically connected to the ground-side electrodes and a second terminal which is grounded; and

a control resistor, which electrically connects the first terminal of the capacitor and the bias potential provider.