A liquid discharge head includes a plurality of discharge holes, a plurality of pressurizing units, a plurality of drive circuits, a switch circuit, and first and second control circuits. The drive signals include a first signal for a pixel of a first size and a second drive signal for a pixel of a second size. The second control circuit controls the switch circuit so that each of the plurality of pressurizing units is connected to the drive circuit outputting the first signal when a droplet forming the pixel of the first size is discharged and is connected to the drive circuit outputting the second signal when a droplet forming the pixel of the second size is discharged. The first control circuit controls the drive circuits so that the drive circuits in charge of outputting the first signal is changed among the plurality of drive circuits.

A liquid discharge head includes an actuator and a drive circuit. The actuator is configured to expand and contract a pressure chambers. The drive circuit is configured to apply a first drive waveform to cause the actuator to discharge a liquid droplet at a first speed, and then a second drive waveform after the first drive waveform to cause the actuator to discharge a liquid droplet at a second speed slower than the first speed.

Provided are an image recording apparatus, a dither mask, and an image recording method capable of reducing occurrence of concentration unevenness without decrease in productivity. In an image recording apparatus that repeats a main scan operation of relatively moving a recording head having a nozzle row with respect to a recording medium in a main scan direction to perform recording and a sub scan operation of relatively moving the recording medium with respect to the recording head in a sub scan direction, a nozzle jetting rate of each nozzle is controlled by a dither mask. The dither mask is subjected to threshold setting so that a sum of a sum of nozzle jetting rates of corresponding nozzles of respective nozzle groups used in recording a first half scan for recording each scan band and a sum of nozzle jetting rates of corresponding nozzles of respective nozzle groups used in recording a second half scan becomes a specific value that is in a defined allowable range, with respect to at least a part of a recording duty range.

An image recording apparatus includes a recording head including a plurality of nozzles from which ink is ejected, a memory, and one or more hardware processors coupled to the recording head and the memory. The one or more hardware processors are configured to: determine, for each of the plurality of nozzles, whether a position of the corresponding nozzle is a position to eject ink; determine whether a successive ejection operation is necessary for a nozzle out of the plurality of nozzles, whose position is determined as the position to eject ink; and cause ink to be successively ejected at the position to eject ink at a predetermined successive ejection frequency from the nozzle that is determined to have the necessity of the successive ejection operation.

In an image processing device, a controller performs: acquiring target image data representing a target image; inputting first and second datasets into a machine learning model and causing the machine learning model to output first and second partial dot data; and generating dot data specifying a dot formation state for each of a plurality of pixels in a print image corresponding to the target image using the first and second partial dot data. The first dataset includes first partial image data and a first value for an input parameter. The second dataset includes second partial image data and a second value for the input parameter. The machine learning model outputs the second partial dot data different from the first partial dot data according to the second value being different from the first value even when the second partial image data is identical to the first partial image data.

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 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 firing chambers or non-firing chambers, so as to produce bands of one or more contiguous firing 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.

An inkjet head comprises a pressure chamber that stores liquid; an actuator that changes a volume of the pressure chamber in response to an applied driving signal; and an applying section that applies the driving signal to the actuator. The driving signal includes a discharge pulse and an oscillation pulse. The discharge pulse enables liquid to be discharged from a nozzle communicating with the pressure chamber. The oscillation pulse is applied before the discharge pulse and has a potential opposite in polarity to that of the discharge pulse to generate pressure oscillation for promoting discharge of the liquid in the liquid. When the driving signal includes two or more successive discharge pulses, a cycle of the discharge pulse is 1.5 times or more and 2.5 times or less as long as a half cycle of a main acoustic resonance frequency of the liquid in the pressure chamber.

A liquid jet head includes a plurality of nozzles adapted to jet liquid, a piezoelectric actuator having a plurality of pressure chambers communicated individually with the nozzles and each filled with the liquid, and adapted to change a capacity of each of the pressure chambers, and a control section adapted to apply at least one pulse signal to the piezoelectric actuator to thereby expand and contract the capacity of the pressure chambers to jet the liquid filling the pressure chamber. The pressure chambers adjacent to each other of the plurality of the pressure chambers are set so as to belong to a plurality of groups different from each other. The control section makes the pulse signals different in timing between the plurality of groups and sets a shift amount of the timing in the pulse signals between the respective groups.

A liquid discharge head includes first and second actuators and a drive circuit. Each of the first and second actuators is configured to expand and contract first and second pressure chambers, respectively. The drive circuit is configured to, during a dot formation cycle apply a first number of discharge pulses to the first actuator to cause the first number of droplets to be discharged from the first pressure chamber and apply a second number of discharge pulses to the second actuator to cause the second number of droplets to be discharged from the second pressure chamber and apply a third number of precursors to the second actuator. The first number is greater than or equal to two. Each of the second and third numbers is greater than or equal to one. A sum of the second and third numbers is less than or equal to the first number.