Inkjet head and inkjet recording apparatus

An inkjet recording apparatus comprising:

• (a) an inkjet head including
• (a-1) a pressure chamber for containing ink,
• (a-2) a nozzle for communicating through said pressure chamber,
• (a-3) a piezoelectric actuator having a piezoelectric element and deforming to increase or decrease a capacity of said pressure chamber due to piezoelectric effect of the piezoelectric element, and
• (a-4) a controller for driving said actuator by supplying signals including ink-ejecting signals for driving said actuator to eject the ink and ink-non-ejecting signals for driving said actuator not to eject the ink, so as to control ink in said chamber to be ejected from said nozzle at a desirable timing;
• and
• (b) a moving device for moving said head relative to a recording medium,
• wherein when said head is moved relative to the recording medium by said moving device, said nozzle ejects ink to carry out recording on the recording medium;
• wherein said controller is operable to drive said actuator so that, when the desirable timing for ejecting ink is such that a frequency of said ink-ejecting signals is less than 20 kHz, ink-non-ejecting signals are supplied between ink-ejecting signals to cause an overall frequency of said signals to be not less than 20 kHz.

An inkjet recording apparatus comprising:

• (a) an inkjet head including
• (a-1) a pressure chamber for containing ink,
• (a-2) a nozzle for communicating through said pressure chamber,
• (a-3) an actuator operating to change a pressure of said pressure chamber, and
• (a-4) a controller for driving said actuator by supplying signals including ink-ejecting signals for driving said actuator to eject the ink and ink-non-ejecting signals for driving said actuator not to eject the ink, so as to control ink in said chamber to be ejected from said nozzle at a desirable timing;
• (b) a first dc motor for moving a carriage to which said inkjet head is mounted in a main scanning direction;
• and
• (c) a second dc motor for moving a recording medium in a sub-scanning direction;
• wherein said controller is operable to drive said actuator so that, when the desirable timing for ejecting ink is such that a frequency of said ink-ejecting signals is less than 20 kHz, ink-non-ejecting signals are supplied between ink-ejecting signals to cause an overall frequency of said signals to be not less than 20 kHz.

An inkjet head comprising:

• (a) a pressure chamber for containing ink;
• (b) a nozzle for communicating through said pressure chamber;
• (c) an actuator operating to change a pressure of said pressure chamber;
• and
• (d) a controller for driving said actuator by supplying signals including ink-ejecting signals for driving said actuator to eject the ink and ink-non-ejecting signals for driving said actuator not to eject the ink, so as to control ink in said chamber to be ejected from said nozzle at a desirable timing;
• wherein said controller is operable to drive said actuator so that, when the desirable timing for ejecting ink is such that a frequency of said ink-ejecting signals is less than 20 kHz, ink-non-ejecting signals are supplied between ink-ejecting signals to cause an overall frequency of said signals to be not less than 20 kHz.