Ink jet printer and ink discharging method of the ink jet printer

An ink jet printer comprising:

• an ink chamber;
• a nozzle connected with the ink chamber;
• a pressure chamber located between the ink chamber and the nozzle;
• a piezoelectric element facing the pressure chamber;
• a temperature sensor for measuring at least one of a temperature of ink and a surrounding temperature of the ink jet printer;
• and
• a controller programmed to perform a first change of voltage applied to the piezoelectric element and a second change of voltage applied to the piezoelectric element and to change a period between the first change and the second change based on the temperature measured by the temperature sensor,
• wherein the controller is programmed to repeatedly perform the first change and the second change so that a plurality of droplets of the ink is discharged from the nozzle to substantially a same point of a print medium,
• the controller is programmed to change a period from the first change to the second change and a period from the second change to the repeated first change based on the temperature,
• the period from the first change to the second change is equal to the period from the second change to the repeated first change, and
• the controller changes each of the periods based on the temperature.

A method for discharging ink from an ink jet printer, the ink jet printer comprising an ink chamber, a nozzle connected with the ink chamber, a pressure chamber located between the ink chamber and the nozzle, and a piezoelectric element facing the pressure chamber, the method comprising:

• a step of performing a first change of voltage applied to the piezoelectric element and a second change of voltage applied to the piezoelectric element;
• a step of measuring at least one of a temperature of the ink and a surrounding temperature of the ink jet printer;
• and
• a step of changing a period between the first change and the second change based on the temperature measured in the measuring step,
• wherein a short period is adopted in the changing step when the temperature is high,
• a long period is adopted in the changing step when the temperature is low,
• a first period is adopted in the changing step when the temperature is higher than a first predetermined temperature,
• a third period is adopted in the changing step when the temperature is lower than a second predetermined temperature,
• the first period is shorter than the third period, and
• the first predetermined temperature is higher than the second predetermined temperature.