An inkjet head driving method includes applying a voltage signal having a combined drive waveform that includes unit drive waveforms to a pressure generator and causing a nozzle to jet ink droplets such that the droplets land on a medium as one droplet. Each unit drive waveform includes a first pulse waveform for jetting a droplet and a second pulse waveform for pulling back the jetted droplet. The first and second pulse waveforms each include an expansion part for expanding a pressure chamber and a following contraction part for contracting the chamber. The combined drive waveform includes a first unit drive waveform and a following second unit drive waveform. A voltage amplitude of the contraction part of the second pulse waveform in the second unit waveform is greater than that of the contraction part of the second pulse waveform in the first unit drive waveform.

A liquid discharge apparatus includes a head and a switching device. The head includes a piezoelectric element and a pressure chamber configured to discharge liquid. The switching device is configured to select application or non-application of a drive voltage waveform to the piezoelectric element. The drive voltage waveform includes a discharge waveform to pressurize and discharge the liquid in the pressure chamber and a damping waveform to suppress residual vibration in the pressure chamber. The damping waveform is disposed after the discharge waveform in time series. The switching device includes a switch and a diode. The switch is configured to be turned on in a falling waveform element of each of the discharge waveform and the damping waveform. The diode is connected in parallel with the switch in a direction opposite to the falling waveform element of each of the discharge waveform and the damping waveform.

There is provided a method for controlling driving of an inkjet head including recording elements each including a nozzle and a driving element. The method includes a pulse width setting step. In this step, when a predetermined number of ink droplets ejected according to the predetermined number of driving pulses are made to land in the same pixel range, the predetermined number of first driving pulses each having a pulse width longer than a reference pulse width and the predetermined number of second driving pulses each having a pulse width shorter than the reference pulse width are combined for each of the recording elements and obtained combinations are respectively output to the recording elements. The predetermined number is two or more.

A liquid discharging apparatus includes: a channel unit having a nozzle and an individual channel; an actuator applying pressure to liquid in the individual channel to discharge the liquid from the nozzle; a driving circuit electrically connected to the actuator and supplying driving signal to the actuator; and a controller. In a case of determining that a single-sided recording is to be executed, the controller supplies the driving signal corresponding to each of gradation values for each of pixels when discharging the liquid toward one of a first surface and a second surface of a recording medium; in a case of determining that the double-sided recording is to be executed, the controller supplies the driving signal corresponding to each of the gradation values for each of the pixels when discharging the liquid toward the first surface and when discharging the liquid toward the second surface.

An inkjet head includes a pressure chamber storing ink, a nozzle communicating with the chamber, an actuator ejecting the ink through the nozzle by changing a volume of the chamber, and a circuit outputting a drive signal to the actuator with a drive waveform having a cycle based on a number of gradation levels being used for printing. When printing is performed using three or more gradation levels, the circuit outputs the signal that has a multi-drop drive waveform including two or more first waveforms for ejecting first to (n−1)-th droplets of the ink where n is equal to or greater than 3, a second waveform for ejecting an n-th droplet of the ink, and an intermediate time between the first waveform for ejecting the (n−1)-th droplet and the second waveform for ejecting the n-th droplet. The intermediate time is longer than a time between two adjacent first waveforms.

According to an embodiment, an inkjet head includes a nozzle that ejects ink, an ink pressure chamber that connects to the nozzle, an actuator that changes a volume of the ink pressure chamber, and an actuator driving circuit that drives the actuator with a driving waveform. The driving waveform includes an ejection pulse portion that changes from a first voltage to a second voltage at which the ink pressure chamber expands and then changes from the second voltage to a third voltage at which the ink pressure chamber contracts so as to eject the ink from the nozzle. The third voltage is between that of the first and second voltages in potential level. The potential difference between the second and third voltages is greater than the potential difference between the third and first voltages.

A liquid discharge apparatus includes a nozzle plate with nozzles and actuators and a drive controller. First and second nozzles are directly adjacent to each other in a first direction. First and third nozzles are directly adjacent to each other in a second direction. The drive controller is configured to apply a drive signal to first, second, and third actuators corresponding to the first, second, and third nozzles, respectively, during a drive cycle. A difference between a first timing at which the drive signal is applied to the first actuator and a second timing at which the drive signal is applied to the second actuator and a difference between the first timing and a third timing at which the drive signal is applied to the third actuator is an odd number multiple of a half of an inherent vibration cycle of the liquid discharge apparatus.

According to one or more embodiments, the inkjet head includes an actuator and a driver. The actuator causes a pressure chamber to expand or contract. The driver applies an ejection pulse to the actuator to eject ink from the pressure chamber. The ejection pulse includes an expansion pulse having a width of 0.75 to 1.25 times a pressure propagation time of the pressure chamber, a rest period after the expansion pulse, and a contraction pulse after the rest period.

There is provided a liquid discharge apparatus including: a conveyer; head chips; a circulation channel; and a controller. Each head chip includes a manifold; a nozzle group, and actuators. Each head chip is configured to execute discharge drive and non-discharge vibration drive. The head chips include: an end head chip; a facing head chip facing the recording medium; and a non-facing head chip not facing the recording medium. The controller is configured to make at least one of a circulation flowing amount of a liquid in the circulation channel in the facing head chip and a frequency of the non-discharge vibration drive by an actuator included in the actuators in the facing head chip larger than those of the non-facing head chip.

A method for depositing droplets onto a medium, utilising a droplet deposition head is provided. The head used in the method includes: an array of fluid chambers separated by interspersed walls, each fluid chamber communicating with an aperture for the release of fluid droplets and each wall separating two neighbouring chambers. Each wall is actuable such that in response to a first voltage, it will deform so as to decrease the volume of one chamber and increase the volume of the other chamber, and, in response to a second voltage, it will deform so as to cause the opposite effect on the volumes of its neighbouring chambers. The method includes the steps of: receiving input data: assigning, based on such input data, all the chambers within the array as either filing chambers or non-firing chambers, so as to produce bands of one or more contiguous filing chambers separated by bands of one or more contiguous non-firing chambers; actuating the walls of certain of the chambers such that: for each non-firing chamber, either one wall is stationary while the other is moved, or the walls move with the same sense, or they remain stationary: and, for each firing chamber the walls move with opposing senses; such actuations result in each firing chamber releasing at least one droplet, the resulting droplets forming bodies of fluid disposed on a line on the medium, such bodies of fluid being separated on the line by respective gaps for each of the bands of non-firing chambers, the size of each such gap generally corresponding in size to the respective band of non-firing chambers. The actuations of the walls of said firing chambers in the actuating step are such that, if only one of the two walls of each firing chamber were actuated in such manner, no droplets would be ejected from that firing chamber. A droplet deposition apparatus, a droplet deposition head and a computer program product are also provided.