An inkjet printing device includes a stage; an inkjet head disposed above the stage and comprising nozzles through which ink is discharged, the ink including bipolar elements extending in a direction; an ink circulation part which supplies the ink to the inkjet head, and to which the ink remaining after being discharged from the inkjet head is supplied; and at least one sensing part disposed between the inkjet head and the ink circulation part and sensing a number of the bipolar elements that are discharged through the nozzles.

An inkjet printing device includes a stage; an inkjet head disposed above the stage and comprising nozzles through which ink is discharged, the ink including bipolar elements extending in a direction; an ink circulation part which supplies the ink to the inkjet head, and to which the ink remaining after being discharged from the inkjet head is supplied; and at least one sensing part disposed between the inkjet head and the ink circulation part and sensing a number of the bipolar elements that are discharged through the nozzles.

An ejection apparatus includes an ejection head having an ejection port, a droplet detection unit, an acquisition unit, a control unit, and a decision unit. The droplet detection unit detects that a droplet ejected from the ejection port has reached a predetermined position. The acquisition unit acquires information regarding a velocity of movement of the detected droplet. The control unit controls the ejection head to eject the droplet from the ejection port. The decision unit decides a number of consecutive ejections of a plurality of droplets from the ejection head based on the acquired information regarding the velocities of each of the plurality of droplets ejected consecutively and detected by the droplet detection unit. If the acquisition unit acquires the information regarding velocities of detected droplets, the control unit controls the ejection head to consecutively eject the droplets from the ejection head based on the decided number of consecutive ejections.

In an example of the disclosure, a web media is advanced through a printer during a printing operation, Tractor-feed holes in a tractor-feed lane of the web media are detected utilizing a sensor and counted as the web media advances. When the count of tractor-feed holes reaches a target tractor-feed hole n, a fiducial detection period is started wherein a sensor is utilized to detect a fiducial. A printing adjustment is determined based upon a time or time period that the fiducial is detected during the fiducial detection period.

In an example of the disclosure, a web media is advanced through a printer during a printing operation, Tractor-feed holes in a tractor-feed lane of the web media are detected utilizing a sensor and counted as the web media advances. When the count of tractor-feed holes reaches a target tractor-feed hole n, a fiducial detection period is started wherein a sensor is utilized to detect a fiducial. A printing adjustment is determined based upon a time or time period that the fiducial is detected during the fiducial detection period.

Examples associated with drop velocity aberrancy detection are disclosed. One example includes firing ink through nozzles of a print-head past sensors to identify drop velocities of the nozzles. A target drop velocity is selected based on the drop velocities of the nozzles. An aberrant nozzles is detected when a nozzle has a drop velocity that deviates from the target drop velocity by a selected threshold. The aberrant nozzle is deactivated, and a good nozzle that will travel over locations traversed by the aberrant nozzle is configured to print portions of a job that would have been printed by the aberrant nozzle.

Examples associated with drop velocity aberrancy detection are disclosed. One example includes firing ink through nozzles of a print-head past sensors to identify drop velocities of the nozzles. A target drop velocity is selected based on the drop velocities of the nozzles. An aberrant nozzles is detected when a nozzle has a drop velocity that deviates from the target drop velocity by a selected threshold. The aberrant nozzle is deactivated, and a good nozzle that will travel over locations traversed by the aberrant nozzle is configured to print portions of a job that would have been printed by the aberrant nozzle.

In an example, a device for sensing a property of a fluid may include an ion-sensitive field effect transistor (ISFET) having a gate, a source, and a drain. The device may also include a first metal element in contact with the gate and a switching layer in contact with the first metal layer. A resistance state of the switching layer is to be modified through application of an electrical field of at least a predefined strength through the switching layer and is to be retained in the switching layer following removal of the electrical field. The device may also include a metal plate in contact with the switching layer, in which the metal plate is to directly contact the fluid for which the property is to be sensed.

A color inkjet printer includes an electrode that emits an electric field into a gap between a printhead and a media transport that carries media past the printhead. Image data generated by an optical sensor after an ink image is printed on the media is analyzed to measure at least one image quality metric. When the measured image quality metric is outside of a tolerance range, the voltage of a voltage source electrically connected to the electrode is adjusted to improve the wetting of the media type with the ink ejected by the printhead.

A color inkjet printer includes an electrode that emits an electric field into a gap between a printhead and a media transport that carries media past the printhead. Image data generated by an optical sensor after an ink image is printed on the media is analyzed to measure at least one image quality metric. When the measured image quality metric is outside of a tolerance range, the voltage of a voltage source electrically connected to the electrode is adjusted to improve the wetting of the media type with the ink ejected by the printhead.