An ink-jet recording apparatus includes: a conveyor conveying a sheet; a recording head including first nozzles, second nozzles, first driving elements corresponding to the first nozzles respectively, and second driving elements corresponding to the 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 through which a clock signal is transmitted, and connected electrically to the first driving elements and the 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 when driving voltage is applied from the head driving circuit. The controller repeatedly executes conveyance processing for conveying the sheet with the conveyor and recording processing in which pattern signals indicating patterns of the driving voltage are outputted serially and a jetting instruction signal is outputted serially.

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.

A drop-on-demand printing method comprising performing the following steps in a printing head: discharging a first primary drop (x21A) of a first liquid to move along a first path; discharging a second primary drop (x21B) of a second liquid to move along a second path; controlling the flight of the first primary drop (x21A) and the second primary drop (x21B) to combine the first primary drop with the second primary drop into a combined drop (x22) at a connection point (x32) within a reaction chamber within the printing head so that a chemical reaction is initiated within a controlled environment of the reaction chamber between the first liquid of the first primary drop and the second liquid of the second primary drop; and controlling the flight of the combined drop (x22) through the reaction chamber along a combined drop path such that the combined drop (x22), during movement along the combined drop path starting from the connection point is distanced from the elements of the printing head.

A liquid ejection head includes: a piezoelectric actuator configured to be deformed depending on a driving pulse applied thereto so as to eject liquid filled in a pressure chamber from a nozzle, a ratio of a first local maximum value which is a largest value among a plurality of local maximum values of an ejection speed of the liquid depending on a pulse width and a second local maximum value which is a second largest value thereamong satisfying a predetermined condition; and a control unit configured to successively apply a first driving pulse and a second driving pulse to the piezoelectric actuator.

Provided are an inkjet printing apparatus and a recovery processing method which can suppress occurrence of defective ejection and can suppress an ink consumption amount. For that purpose, information relating to a condensation degree of ink is obtained, and ejection operation is made in accordance with the obtained condensation degree of ink.

A liquid discharging head includes a discharge port that discharges a liquid, a pressure chamber that communicates with the discharge port, and an energy generating element that is disposed in the pressure chamber. In the liquid discharging head, the discharge port is provided with a plurality of projections that project towards a central portion of the discharge port from an inner peripheral edge of the discharge port, and an interval between the projections at a location where the projections are closest to each other is 5 m or less.

A liquid discharge apparatus includes a liquid discharger and circuitry. The liquid discharger includes a nozzle to discharge liquid. The circuitry is configured to generate and output a common drive waveform including a plurality of drive pulses for discharging the liquid; select one or more of the plurality of drive pulses from the common drive waveform and apply the one or more of the plurality of drive pulses to a pressure generating element of the liquid discharger; and adjust, with different adjustment values, application waveform shapes of at least two of the plurality of drive pulses applied to the pressure generating element.

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.

Methods and systems are described herein for driving droplet ejection devices with multi-level waveforms. In one embodiment, a method for driving droplet ejection devices includes applying a multi-level waveform to the droplet ejection devices. The multi-level waveform includes a first section having at least one compensating edge and a second section having at least one drive pulse. The compensating edge has a compensating effect on systematic variation in droplet velocity or droplet mass across the droplet ejection devices. In another embodiment, the compensating edge has a compensating effect on cross-talk between the droplet ejection devices.

Methods and systems are described herein for driving droplet ejection devices with multi-level waveforms. In one embodiment, a method for driving droplet ejection devices includes applying a multi-level waveform to the droplet ejection devices. The multi-level waveform includes a first section having at least one compensating edge and a second section having at least one drive pulse. The compensating edge has a compensating effect on systematic variation in droplet velocity or droplet mass across the droplet ejection devices. In another embodiment, the compensating edge has a compensating effect on cross-talk between the droplet ejection devices.