In an example, a printing apparatus includes a controller, wherein the controller may be to compare a historic usage of a first printhead nozzle with a historic usage of a second printhead nozzle which is located on a same printhead as the first nozzle. The controller may be to determine that the historic usage of the first nozzle is higher than the historic usage of the second nozzle, and in response identify a currently operational third printhead nozzle, for which the second nozzle is able to compensate; and turn off the third nozzle, and operate the second nozzle at a higher firing frequency to compensate for the third nozzle.

A controller for an inkjet printing device is configured to predict a remaining time period until a failure of the nozzle on the basis of a time curve of offset measurement values with regard to the offset of the ink droplets ejected by said nozzle. A compensation measure may be introduced promptly, before the actual failure of the nozzle on the basis of the prediction in order to have the effect that the compensation measure takes effect at latest at the point in time of the failure of the nozzle, and thus an interruption of the print quality may be prevented.

A liquid ejecting apparatus includes: an acquisition unit that acquires first vibration information on an inspection target ejecting portion out of the ejecting portions concerning a vibration generated in a first detection period included in a first period in which the liquid ejecting apparatus forms a first printed image on the medium, and acquires second vibration information on the inspection target ejecting portion concerning a vibration generated in a second detection period corresponding to the first detection period, the second detection period being included in a second period that starts after completion of the first period, in which the liquid ejecting apparatus forms a second printed image related to the first printed image on the medium. The liquid ejecting apparatus also includes an inspection unit that inspects a ejection state of the liquid from the inspection target ejecting portion based on the first vibration information and the second vibration information.

In some examples, a fluid dispensing device includes a plurality of fluidic actuators, and a plurality of sense measurement storage elements to store sense measurement indicators for indicating whether sense measurement is to be performed for fluidic actuators of the plurality of fluidic actuators. The fluid dispensing device further includes a controller to control setting of the sense measurement indicators in the sense measurement storage elements to select which fluidic actuator is to be subject to a sense measurement.

A drive waveform acquisition unit that acquires a drive waveform; a drive voltage generation unit that generates a drive voltage; and a drive voltage supply unit that supplies the drive voltage are included. The drive waveform acquisition unit acquires an overflow waveform used to generate an overflow drive voltage. The drive voltage generation unit generates the overflow drive voltage including one or more overflow pulses corresponding to a period of 0.2 seconds or more and 90 seconds or less. The overflow pulses have a pulse width of 1.2 times or more and 1.8 times or less and an amplitude of 0.3 times or more and 0.8 times or less, and at least one of a rising period or a falling period of 0.3 times or less with respect to a jetting pulse.

There is provided a liquid ejection apparatus including: a liquid ejection head that includes nozzles; a signal output circuit that outputs a signal that varies depending on whether at least part of the nozzles includes a discharge-defective nozzle; and a controller. The controller is configured to discharge a liquid on a medium by using a partial discharge mode; perform determination, for at least one nozzle included in the nozzles based on the signal from the signal output circuit, about whether the discharge-defective nozzle is included therein; and set, based on the signal from the signal output circuit, the part of the nozzles not to include the discharge-defective nozzle when the liquid is discharged from the liquid ejection head on the medium by using the partial discharge mode and when the controller has determined that the discharge-defective nozzle is included in the nozzles.

A liquid discharge apparatus includes a liquid discharge head, circuitry, and an image detector. The liquid discharge head includes multiple nozzles and discharges a liquid from the multiple nozzles. The circuitry causes the liquid discharge head to discharge the liquid onto a recording medium to form an image in an image area of the recording medium in a printing operation. The image detector reads the image formed on the recording medium. The circuitry further causes the liquid discharge head to discharge the liquid onto at least one of a leading end or a trailing end of the recording medium to form a flushing pattern different from the image in a flushing operation, causes the image detector to read the flushing pattern, detect a defective part in the flushing pattern read by the image detector, and identify a defective nozzle among the multiple nozzles based on defective part.

A liquid ejecting apparatus includes a supply section configured to selectively supply a first driving signal that drives a piezoelectric element to form an image or a second driving signal that drives the piezoelectric element to determine whether a foreign matter adheres to an inner wall of a nozzle opening, and a determination section that determines whether a foreign matter adheres to the inner wall. The second driving signal includes a first partial signal having its potential changed from a first potential to a second potential, and a second partial signal having its potential changed from the second potential to the first potential. The determination section determines, after the first partial signal is supplied to the piezoelectric element, based on vibration generated in the piezoelectric element due to supply of the second partial signal, whether a foreign matter adheres to the inner wall.

A non-transitory computer readable medium recorded with a program for controlling an external apparatus which has a memory and which is configured to communicate with a liquid ejecting apparatus is provided. The program allows a computer to acquire nozzle information from the liquid ejecting apparatus so that the nozzle information is stored in the memory. The program allows the computer to execute the nozzle information acquiring process at a first timing if the nozzle information, which is stored in the memory, fulfills a first condition, or the program allows the computer to execute the nozzle information acquiring process at a second timing having a frequency lower than that of the first timing if the nozzle information, which is stored in the memory, fulfills a second condition.

An ink jet printing apparatus comprises a controller and a printhead control unit positioned between the controller and the printhead and configured to control the printhead upon an instruction from the controller. The controller comprises a control unit configured to, in a case where transmission of an instruction to the printhead control unit failed, if the instruction is an instruction included in a first communication sequence performed periodically with respect to the printhead control unit in order to control the printhead, not execute a retry of the failed instruction, and in a case where the instruction is an instruction included in a second communication sequence performed aperiodically with respect to the printhead control unit in order to control the printhead, retry the failed instruction.