According to one embodiment, an ink jet head includes an actuator configured to cause ink to be discharged from a pressure chamber associated with the actuator, and a control unit configured to apply to the actuator in a droplet ejection process an auxiliary signal that does not cause ink to be discharged from the pressure chamber, and a discharge signal that causes ink to be discharged from the pressure chamber.

A first output section outputs a first parameter calculated for each nozzle in a group obtained by dividing the nozzles into groups for each certain number so that density unevenness of ink ejected from each nozzle in the group is corrected. A second output section outputs a second parameter calculated for each group so that change rate of the density unevenness between groups is corrected. A first register circuit divides first parameters for each nozzle in the group and stores the first parameters. A second register circuit divides second parameters for each group and stores the second parameters. A multiplication section sequentially multiplies the first parameters by the second parameters. A conversion section converts a multiplication value to correction data of each nozzle. A setting section sets the correction data in a memory.

An inkjet head contains a piezoelectric member which alternately includes plural first grooves and plural second grooves respectively constituted by a pair of side surfaces and a bottom surface; a first electrode on at least one of a pair of the side surfaces of each first groove; a second electrode on the side surface to face the first electrode across the piezoelectric member of each second groove; and a driving circuit including plural first drivers for each first electrode and inputting a common first driving waveform to each first electrode, and plural second drivers for each second electrode and inputting a second driving waveform of each second electrode corresponding to print data to each second electrode.

A first output section outputs a first parameter calculated for each nozzle in a group obtained by dividing the nozzles into groups for each certain number so that density unevenness of ink ejected from each nozzle in the group is corrected. A second output section outputs a second parameter calculated for each group so that change rate of the density unevenness between groups is corrected. A first register circuit divides first parameters for each nozzle in the group and stores the first parameters. A second register circuit divides second parameters for each group and stores the second parameters. A multiplication section sequentially multiplies the first parameters by the second parameters. A conversion section converts a multiplication value to correction data of each nozzle. A setting section sets the correction data in a memory.

In accordance with an embodiment, an inkjet head comprises a pressure chamber configured to house ink; an actuator configured to be arranged corresponding to the pressure chamber; a plate configured to have a nozzle communicating with the pressure chamber; and a driving circuit configured to drive the actuator, wherein the drive circuit applies an auxiliary pulse signal which contains an expansion pulse for expanding the volume of the pressure chamber and a contraction pulse for contracting the volume of the pressure chamber in such a degree as not to eject an ink drop from the nozzle to the actuator before enabling the ink drop to be ejected from the nozzle communicating with the pressure chamber by applying the expansion pulse and the contraction pulse as a drive pulse signals.

An overvoltage is prevented from being applied to a circuit. A full-bridge circuit is provided with a first switch having an output terminal connected to one end of a capacitive load, and switching output to the output terminal between a power supply and a ground, a second switch having an output terminal connected to the other end of the capacitive load, and switching output to the output terminal between the power supply and the ground, a first waveform generation section adapted to output a drive waveform for driving the first switch, a second waveform generation section adapted to output a drive waveform for driving the second switch, a detection section adapted to detect voltages of the drive waveforms output by the first waveform generation section and the second waveform generation section, and a control section adapted to control the output of either of the switches based on the voltages detected by the detection section.

An actuator device includes: an actuator including a first element contact; and a wire member including (a) a first contact connected to the first element contact and (b) a first wire configured to conduct with the first contact. A first wide portion is formed at a distal end portion of the first wire at an edge portion of the wire member. The first wide portion is disposed beyond the first element contact in a wire direction of the first wire. The first contact is disposed at a basal end portion of the first wire. The basal end portion is located further from the edge portion of the wire member than the first wide portion. The first contact is connected to the first element contact.

A first output section outputs a first parameter calculated for each nozzle in a group obtained by dividing the nozzles into groups for each certain number so that density unevenness of ink ejected from each nozzle in the group is corrected. A second output section outputs a second parameter calculated for each group so that change rate of the density unevenness between groups is corrected. A first register circuit divides first parameters for each nozzle in the group and stores the first parameters. A second register circuit divides second parameters for each group and stores the second parameters. A multiplication section sequentially multiplies the first parameters by the second parameters. A conversion section converts a multiplication value to correction data of each nozzle. A setting section sets the correction data in a memory.

In accordance with an embodiment, an inkjet head comprises an ejection section and a driving section. The ejection section ejects ink according to the operations of an actuator. In order to make the ejection section eject different amount of ink for different drops, the driving section applies voltage to the actuator of the ejection section such that the ejection section ejects ink continuously based on the printing data indicating the times the ejection section ejects ink and a position flag designating a drop frame number where ink starting to be ejected.

An inkjet head drive apparatus comprises a pressure chamber, an actuator, a nozzle and a drive signal output section. The pressure chamber accommodates an ink. The actuator increases or decreases volume of the pressure chamber through an applied a voltage. The nozzle is connected with the pressure chamber to eject the ink through the change in the volume of the pressure chamber. When an ejection pulse for the ejection of the ink from the nozzle is repeated for equal to or greater than three times, the drive signal output section outputs a drive signal having a driving waveform including an initial ejection pulse having a first voltage amplitude and the second ejection pulses and the pulses thereafter having a second voltage amplitude smaller than the first voltage amplitude to the actuator.