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.

A liquid discharging head includes a channel member which has a plurality of individual channels, each of the plurality of individual channels having a pressure chamber communicating with a nozzle, and a piezoelectric actuator which is configured to make the liquid discharge from the nozzle by causing a change in a pressure on a liquid inside the pressure chamber. The piezoelectric actuator has a thin-film piezoelectric element, and when a Helmholtz natural frequency of the pressure chamber is let to be Fr (kHz) and a diameter of the nozzle is let to be D (?m), a relationship
D<?0.0313?Fr+25.62 (provided that, 100 kHz?Fr)
is satisfied, and a viscosity of the liquid discharged from the nozzle is not higher than 5 mPa.Math.s.

A liquid ejection head includes a nozzle plate including a nozzle that ejects a liquid, a pressure chamber communicating with the nozzle, an actuator changing a volume of the chamber according to a signal, and a drive circuit issuing the signal that includes: one or more first ejection waveforms each including a first expansion pulse and a first contraction pulse at a first time after the first pulse, and a second ejection waveform including a second expansion pulse and a second contraction pulse at a second time after the second pulse, the second time being longer than the first time, and one or more of first to (n?1)-th drops are ejected by the first waveforms, and an n-th drop is ejected by the second waveform where n is a number of drops ejected for one pixel.

According to one embodiment, a driving device includes a head driver configured to generate and apply a driving signal to an actuator for ejecting a liquid from a pressure chamber connected to a nozzle, the driving signal including a contraction pulse, the contraction pulse causing the actuator to contract a volume of the pressure chamber, and end application of the contraction pulse when a flow rate of the liquid from the nozzle has a negative value in a liquid ejection direction from the nozzle.

In an image processing apparatus, a controller generates print data using target image data. The print data represents dot formation states classified for respective pixels. Each dot formation state is classified into a one of a plurality of dot types. The controller determines a dot type from a plurality of dot types including a first type dot and second type dot. The first type dot is formed by a first process for supplying a pressure applying section with a specific signal. The second type dot is formed by a second process that is not for supplying the pressure applying section with the specific signal. The first type dot is to be formed in an edge printing area. The first type dot is not to be formed but the second type dot is to be formed in an interior printing area.

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.

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.

An inkjet printer that is configured to perform multi-pass printing operations includes at least one printhead, a memory and a controller. The controller receives a input row of image data for one pass including a plurality of pixels. The controller uses a table of index lookup offsets in the memory to generate a row of output image data with at least one pixel at a first index in the input row being located at a second index in the output row. The controller operates the inkjets in the printhead to eject at least one drop of ink using an inkjet in the printhead that corresponds to the second index in the output row and that is different than another inkjet in the printhead that corresponds to the first index in the input row.

In accordance with an embodiment, a liquid discharge head comprises a number of times controller and a discharge amount controller. The number of times controller controls the number of times droplets are discharged for one pixel based on input image data. The discharge amount controller controls a discharge amount of the droplet based on the image data.

In accordance with an embodiment, a driving waveform generating device comprises an input module, a setting module, and a generating module. The input module inputs setting data for setting a driving waveform. The setting module sets an order of waveforms constituting the driving waveform based on the setting data for the driving waveform of each gradation. The generating module generates the driving waveform of a desired gradation based on the setting.