There is provided a liquid droplet discharging control device for a liquid droplet discharging apparatus which includes a liquid droplet discharging head in which a plurality of nozzles discharging liquid droplets are formed, discharges liquid droplets while relatively moving the head and a medium in a direction intersecting a direction in which the nozzles are arranged. The liquid droplet discharging control device includes a controller that causes a first nearby nozzle, which discharges a dot adjacent to a dot row corresponding to a predetermined nozzle which is not capable of discharging a liquid droplet, to discharge a liquid droplet for a dot of a large size and that causes a second nearby nozzle, which is separated from the predetermined nozzle and discharges a dot adjacent to a dot row corresponding to the first nearby nozzle, to discharge no liquid droplet for a dot.

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.

Image data may indicate an average number of drops of printer fluid per pixel. Print data may be generated such that a total number of drops of printing fluid are deposited to a print medium during a pass in a forward direction and a pass in the reverse direction according to a distribution.

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 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 digital printing system includes a print head and a processor. The print head is configured to jet droplets of ink. The a processor is further configured to translate a required shade of a color, to be printed at a given location on a substrate by the print head, into a sequence of pulses, the sequence including: (a) up to a predefined maximum number of driving pulses that cause the print head to jet respective droplets, and (b) a tickling pulse, which has a smaller amplitude than the driving pulses and which causes the print head to jet a droplet smaller than the droplets jetted in response to the driving pulses. The processor is additionally configured to apply the sequence of pulses to the print head.

According to one embodiment, an inkjet head driving device includes an ejection pulse generation circuit configured to generate an ejection pulse to be applied to an actuator for ejecting ink from a pressure chamber connected to a nozzle, and an expansion pulse generation circuit configured to generate an expansion pulse to be applied to the actuator after at least one ejection pulse, the expansion pulse causing the actuator to expand a volume of the pressure chamber to prevent ink from being ejected from the nozzle.

An apparatus for ejecting liquid, includes a liquid ejection head with a plurality of individual liquid chambers and a common liquid chamber, and a pressure generator to generate a pressure for pressing liquid in the individual liquid chambers. A pulse interval, which is a time from the end of a push-in waveform element of a preceding driving pulse to the start of a pull-in waveform element of a succeeding driving pulse in the two continuous driving pulses is set to a timing when a pressure difference among the pressure fluctuations in the individual liquid chambers, caused by the pressure fluctuation in the common liquid chamber, becomes smaller.

An ink jet head drive device includes a pressure chamber in which a liquid can be contained, an actuator configured to change a pressure on the liquid in the pressure chamber by changing a volume of the pressure chamber in response to a drive signal, a nozzle through which the liquid contained in the pressure chamber can be ejected when an ejection pulse is supplied to the actuator, and a drive circuit configured to output the drive signal to the actuator as a drive waveform having a first pulse group and a second pulse group following the first pulse group when at least three consecutive ejection pulses are included in the drive waveform. All ejection pulses in the first pulse group have a first voltage amplitude, and all ejection pulses in the second pulse group have a second voltage amplitude that is smaller than the first voltage amplitude.

An ink-jet recording apparatus includes: a recording head including first and second nozzles and first and second driving elements corresponding to the first and second nozzles respectively; a controller; and a head driving circuit connected to the controller by first and second signal lines and a third signal line for transmitting a clock signal, the head driving circuit connected electrically to the first and second driving elements. Each of the first and second driving elements is driven to jet an ink droplet from one of the first and second nozzles corresponding thereto when driving voltage is applied from the head driving circuit. The controller executes relative movement processing for the recording head and a sheet in parallel with recording processing in which pattern signals of the driving voltage are outputted serially to the first signal line and a jetting instruction signal is outputted serially to the second signal line.