A system is disclosed. The system at least one physical memory device to store ink estimation logic and one or more processors coupled with the at least one physical memory device, to execute the ink estimation logic to receive one or more gray level histograms, receive one or more halftone designs and generate estimated ink usage data for each of one or more color planes based on the gray level histograms and the halftone designs, wherein each gray level histogram corresponds to one of the one or more color planes, and each halftone design corresponds to one of the one or more color planes.

Disclosed is a method of providing adjustment data for a droplet deposition head (such as a printhead), or a data processing component therefor. The method makes use of test data, which has been collected by operating the droplet deposition head (or a test droplet deposition head of substantially the same construction, e.g from the same batch), using a set of test waveforms, at a number of frequencies within a test range, and by recording the volume and velocity of the thus-ejected droplets, with these recorded values (vol.sub.r, vel.sub.r) being represented within the test data. Each of the set of test waveforms includes a basic drive waveform and a number of adjusted drive waveforms, each of which corresponds to the basic drive waveform, but with a particular waveform parameter adjusted by a corresponding amount. This waveform parameter is a continuous variable, such as pulse width or pulse amplitude. The method further includes, determining adjustment values corresponding to a number of adjustment frequencies, each adjustment value corresponding to an amount of adjustment for the waveform parameter that, based on the test data, is expected to result in adjusted values for droplet volume and velocity of, respectively, vol.sub.a and vel.sub.a, which are substantially equal to targeted values for droplet volume and velocity, vol.sub.T and vel.sub.T. The method outputs adjustment data representing such adjustment values and their associated adjustment frequencies, for example in the form of values for a look-up-table. Also disclosed is a droplet deposition apparatus that includes a droplet deposition head with data storage having stored thereon a set of adjustment data. The head uses the adjustment data to actuate its actuator elements with a drive waveform that is based on a basic drive waveform, but with a particular waveform parameter being adjusted by an adjustment value, which is represented by the set of adjustment data and which is determined based on it being associated with the current operating frequency of the actuator element in question. The waveform parameter is again a continuous variable. The adjustment data enable the head to eject droplets at frequencies within an operating range for the head whose values for droplet volume and velocity are substantially equal to targeted values for droplet volume and velocity, vol.sub.T and vel.sub.T.

There is provided a liquid discharge apparatus, including: a conveyer; a head having a nozzle surface formed having a nozzle from which a liquid is discharged on a recording medium conveyed by the conveyer; a carriage carrying the head and configured to be movable in a scanning direction parallel to the nozzle surface in a movement range including a facing range that faces a passing area where the recording medium conveyed by the conveyer passes; a first conductor for detection arranged at a first side in the scanning direction relative to the passing area; and a second conductor for detection arranged at a second side, which is opposite to the first side, in the scanning direction relative to the passing area.

Example implementations relate to a method to manage printhead operational life; the method comprising firing at least one nozzle of a printhead according to an associated firing parameter to produce a respective drop of print liquid, measuring a parameter associated with the drop of print liquid, and adjusting the firing parameter in response to the measuring to reduce the measured parameter associated with the drop of print liquid on a subsequent firing while maintaining the firing parameter at or above a predetermined parameter limit to maintain print image quality.

In an example, a print apparatus includes a printhead carriage to receive a printhead comprising a print agent ejection nozzle, a drop detector to acquire a signal indicative of variations in a parameter detected by the drop detector over a period of drop detection, a memory to hold a print agent ejection signature, and processing circuitry. The processing circuitry includes a convolution module to convolve the drop detector signal with the print agent ejection signature, and the processing circuitry is to determine, from an output of the convolution module, an indication of similarity between the drop detector signal and the print agent ejection signature.

A system is disclosed. The system at least one physical memory device to store ink estimation logic and one or more processors coupled with the at least one physical memory device, to execute the ink estimation logic to receive one or more gray level histograms, receive one or more halftone designs and generate estimated ink usage data for each of one or more color planes based on the gray level histograms and the halftone designs, wherein each gray level histogram corresponds to one of the one or more color planes, and each halftone design corresponds to one of the one or more color planes.

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.

A printing apparatus for printing using a printhead including a plurality of nozzles each configured to discharge ink and a plurality of sensors, corresponding to the plurality of nozzles, for detecting a discharge state of ink from the plurality of nozzles, judges a discharge state. More specifically, the apparatus prints, based on print data, an image by driving the printhead under a first drive condition to discharge the ink from the printhead to a first area, discharges ink to a second area different from the first area by driving the printhead, based on inspection data, under a second drive condition different from the first drive condition, and judges a discharge state of each nozzle by monitoring an output from each sensor at a timing of driving the printhead under the second drive condition.

A method and apparatus for collecting sample data from a liquid droplet dispensation system is provided.

A printing device comprises a droplet generator for generating a droplet of printing fluid, a droplet detector for detecting a generated droplet of printing fluid, and a controller. The droplet detector is moveable along an axis. The controller is to cause the droplet detector to be positioned at a known location along the axis, cause the droplet generator to generate a droplet, receive a measurement signal from the droplet detector, and determine a location of the droplet generator based on the received measurement signal and the known location.