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.

A droplet deposition apparatus comprising a droplet deposition head, a fluid supply and a controller, wherein: the droplet deposition head comprises one or more fluid chambers each having a nozzle, a fluid inlet path having a fluid inlet into the head, and ending in the one or more nozzles, and a fluid return path starting at the one or more nozzles and ending in a fluid return of the head; each fluid chamber comprises two opposing chamber walls comprising piezoelectric material and deformable upon application of an electric drive signal so as to eject a fluid droplet from the nozzle; the fluid supply is configured to supply a fluid to the fluid inlet at a differential pressure as measured between the fluid inlet and the fluid return; and the controller is configured to apply a drive signal to the piezoelectric chamber walls such that the nozzle or nozzles deposit droplets of a fluid having a viscosity in the range from 45 mPa.Math.s to 130 mPa.Math.s at a jetting temperature between 20° C. and 90° C., and wherein the differential pressure applied by the fluid supply causes a fluid return flow into the fluid return at a rate of between 50 ml/min and 200 ml/min. A method of operating the droplet deposition apparatus, and a control system for carrying out the method, are also provided.

According to one embodiment, an inkjet head includes a pressure chamber for ink, a nozzle plate including a nozzle connected to the pressure chamber, an actuator to change a volume of the pressure chamber, and a drive circuit that drives the actuator. The drive circuit drives the actuator according to a drive waveform including an expansion waveform, a first weak contraction waveform, a contraction waveform, and a second weak contraction waveform.

A liquid droplet discharge apparatus includes a discharge head having a nozzle for discharging liquid droplets onto a printing medium and an actuator for applying pressure to liquid in a pressure chamber communicated with the nozzle; a waveform generating circuit for generating driving waveforms of signals for driving the actuator; a surface information acquiring device configured to acquire information about a surface of the printing medium; and a controller. The controller calculates a volume of a recess on the printing medium based on the information acquired by the surface information acquiring device; causes the waveform generating circuit to generate a driving waveform for filling up the recess in accordance with the volume of the recess; and drives the actuator in accordance with the driving waveform generated by the waveform generating circuit such that the liquid droplets are discharged from the nozzle to the recess.

An image forming apparatus includes: a piezoelectric element with a common electrode on one side and an individual electrode on another side; a nozzle; and circuitry. The circuitry selects one from drive signals and supplies the one drive signal to the piezoelectric element via the individual electrode, to discharge a droplet through the nozzle to form an image. Each drive signal includes waveform pulses including a main pulse that rises in a slope shape during a rising time and finishes rising at an end time. The circuitry generates the drive signals so that the end time of a less influential drive signal other than a most influential drive signal falls within a range of the rising time of the main pulse of the most influential drive signal; selects the one drive signal based on an image to be formed; and supplies the one drive signal to the piezoelectric element.

According to one embodiment, a liquid ejection head includes a pressure chamber that contains a liquid, an actuator to change the pressure in the pressure chamber according to an applied drive signal, and a drive circuit to apply a first drive signal to the actuator when a single droplet is to be ejected from the pressure chamber and a second drive signal to the actuator when two or more droplets are to be ejected in series from the pressure chamber. The first drive signal has a first auxiliary pulse before a first ejection pulse. The second drive signal has a second auxiliary pulse before the first ejection pulse. A pulse width of the first auxiliary pulse is greater than a pulse width of the second auxiliary pulse.

The present invention discharges ink from a plurality of inkjet heads and is used when performing drive whereby one droplet or a plurality of droplets are discharged onto and united on one pixel. A drive signal includes a drive waveform comprising N number (N being an integer of at least 2) of drive waveform elements and is configured so as to fulfil the relationship 1.1 Tc≤Ts≤1.4 Tc, when Tc is the natural vibration cycle determined from the inkjet head structure and Ts is the time from the start point of the drive waveform to the start point of the subsequent drive waveform. As a result, velocity deviation caused by the resonant frequency of a piezoelectric actuator driving the inkjet head can be suppressed when driving an inkjet head using multiple gradations.

A grayscale inkjet printing method including the steps of: a) supplying a pigmented inkjet ink to a grayscale print head having nozzles with an outer nozzle surface area smaller than 500 μm.sup.2 and having an acoustic resonance period ARP of not more than 5.5 μs; and b) applying a voltage wave form for ejecting pigmented inkjet ink from a nozzle of the grayscale print head within one jetting cycle; wherein the pigmented inkjet ink has a viscosity of at least 3.8 mPa.Math.s at jetting temperature and a shear rate of 1,000 s.sup.−1; wherein the voltage wave form for ejecting the largest ink droplet includes, in chronological order, a first ejecting pulse having an amplitude A1 and a second ejecting pulse having an amplitude A3 with the amplitude A1 complying with the relationship: 0.50×A3<A1<1.40×A3; and wherein a time period between the end time of the first ejecting pulse and the end time of the second ejecting pulse defines an idle time period including no other ejecting pulse, the time period having a duration between 1.5 to 2.5 times the acoustic resonance period ARP; and wherein any non-ejecting pulse having an amplitude A2 present during the idle time period complies with the relationship: A2≤0.15×A3. An inkjet printing system is also disclosed.

A jet parameter generation system according to an embodiment of the present disclosure includes a data acquisition section, and a parameter generation section for generating a predetermined jet parameter, using a predetermined analytical method of taking a predetermined input parameter as an explanatory variable and taking a predetermined jet parameter as an objective variable. The parameter generation section determines which one of a first standard for setting a voltage value with which a drop volume of the liquid to be a reference is obtained and a second standard for setting a voltage value with which an ejection speed of the liquid to be a reference is obtained is to be selected, selects a first explanatory variable group when determining to select the first standard, while selecting a second explanatory variable group when determined to select the second standard, and uses the predetermined analytical method using just selected one of the first explanatory variable group and the second explanatory variable group to thereby generate the predetermined jet parameter.

A liquid ejection apparatus includes a liquid ejection unit with a plurality of nozzles and a corresponding plurality of actuators. A drive waveform generation circuit is configured to generate drive waveforms having different drive timings. An actuator drive circuit is configured to apply a first drive waveform to a first actuator in a liquid ejection operation and a second drive waveform to a second actuator in the liquid ejection operation during which the first and second actuators are to be driven at a same nominal time. The first driving waveform is different from the second drive waveform, and the first actuator is at a position electrically closer along a predetermined direction to a power supply electrode than is the second actuator.