Herein is described a method involving a drop detector. The method may comprise: ejecting ink drops from the nozzles on a printhead toward a drop detector. A drop characteristic may then be determined from the drop detector for each ink-jet nozzle. Drop characteristics for the nozzles across the printhead may be collated into a data set, and compared with a predetermined data set for a printhead having predetermined print behaviour to determine if and how the data sets differ in terms of the pattern of drop characteristics across the printheads. If the data sets differ, a recovery strategy may be selected based how the data sets differ in terms of the pattern of drop characteristics across the printheads. A system and computer readable medium are also described herein.

A droplet analysis unit capable of measuring and digitizing the meniscus shape, motion, and position of ink droplets and a substrate treatment apparatus including the droplet analysis unit are provided. The substrate treatment apparatus includes: a process treatment unit supporting a substrate while the substrate is being treated; an inkjet head unit treating the substrate by ejecting a substrate treatment liquid onto the substrate using a plurality of nozzles; a gantry unit moving the inkjet head unit over the substrate; and a droplet analysis unit measuring a meniscus in each of the nozzles that is associated with the substrate treatment liquid, wherein the droplet analysis unit measures and quantifies three-dimensional (3D) information regarding the meniscus based on chromatic aberration.

The droplet velocities of the nozzles of different groups of nozzles of a print head of an inkjet printing device are determined for different line clock rates. An optimized operating line clock rate is then determined for the operation of the printing device, where the deviation between the droplet velocities of the nozzles of the different groups is reduced (e.g. minimized). The droplet positioning along the transport direction of a recording medium may be advantageously homogenized via the convergence of the droplet velocities.

In a state where a distance from an ejection port surface of an ejection head to a predetermined position corresponds to a first distance, a period detection unit detects a first period from when ejection of a droplet from an ejection port is started until when a droplet detection unit detects the droplet, and in a state where the distance from the ejection port surface of the ejection head to the predetermined position is changed to a second distance by a change unit, the period detection unit detects a second period from when ejection of a droplet from the ejection port is started until when the droplet detection unit detects the droplet, the second distance being different from the first distance. A calculation unit calculates an ejection speed of the droplet, based on the first distance, the second distance, the first period, and the second period.

A droplet discharge apparatus may include a droplet discharge unit configured to discharge droplets of a target substance stored in a tank at intervals through an opening of a nozzle connected to the tank, a speed sensor configured to measure the speed of a droplet discharged from the droplet discharge unit, and a calculation unit configured to calculate the volume of the target substance consumed per unit time, based on cross-sectional area of the opening of the nozzle and the speed of the droplet.

A drop detector includes a printed circuit board (PCB) including a number of optical channels each formed by a light emitter and a light detector and a number of holes defined in the PCB over which the optical channels pass over and through which a number of ejected drops from a number of printheads pass through wherein each of the number of holes defined in PCB are sized to contour the shape of the number of the printheads.

A print assembly includes: a printhead having a plurality of inkjet nozzle devices; and an array of synthetic jet devices configured to provide a jet flow in a vicinity of ink droplets ejected by the inkjet nozzles.

A printing apparatus for printed electronics according to the present invention may include: ejection head units which each have at least one nozzle for ejecting ink droplets to perform drop-on-demand or continuous printing; a jetting observation unit which is provided at one side of the nozzle and configured to observe the ink droplet ejected from the nozzle; a lighting unit which is provided at the other side of the nozzle and configured to provide light to the jetting observation unit; an alignment observation unit which is configured to observe an aligned state between the nozzle and a substrate; and a fluid supply unit which is configured to supply the ink to the nozzle, in which the ejection head units include a single-nozzle head unit, and a multi-nozzle head unit provided separately from the single-nozzle head unit.

A method of detecting droplets of printing fluid output from a nozzle array includes, in an example, grouping a number of nozzles into a number of individual groups of nozzles and sequentially detecting, with a printing fluid detector, printing fluid ejected from each group of nozzles using a linear position encoder to synchronize the position of the printing fluid detector wherein the printing fluid detector stops moving while detecting each group of nozzles.

In a method of inspecting liquid chemicals discharged from an ink jet head according to example embodiments, at least two laser beams may be irradiated onto the liquid chemicals discharged from the ink jet head, and the conditions of the liquid chemicals may be identified by detecting an interference pattern obtained from a laser scattering generated by passing the liquid chemicals through the at least two laser beams.