Abstract: In some examples, a controller receives impedance sensor values from an impedance sensor in a printhead, determines whether the impedance sensor values correlate to a production of an effective drive bubble for the printhead, and issues a command to modify a firing parameter for a fluid ejector of the printhead based on the impedance sensor values.

Abstract: A microfluidic device can include: a channel; a fluid inlet to pass fluid into the channel from a reservoir; a sensor disposed in the channel; and a pump actuator disposed in the channel apart from the sensor to induce fluid flow into the channel.

Abstract: In some examples, a controller receives impedance sensor values from an impedance sensor in a printhead, determines whether the impedance sensor values correlate to a production of an effective drive bubble for the printhead, and issues a command to modify a firing parameter for a fluid ejector of the printhead based on the impedance sensor values.

Abstract: In some examples, a printhead includes a firing chamber to receive printer fluid, an ejector positioned in the firing chamber to eject printer fluid droplets from the printhead, and a nozzle in fluid communication with the firing chamber. The printhead can further include an impedance sensor positioned in the firing chamber to contact printer fluid to measure impedance values of the printer fluid. The impedance sensor can be connectable to a controller to transmit impedance values of printer fluid to the controller.

Abstract: In some examples, a printhead includes a firing chamber to receive printer fluid, an ejector positioned in the firing chamber to eject printer fluid droplets from the printhead, and a nozzle in fluid communication with the firing chamber. The printhead can further include an impedance sensor positioned in the firing chamber to contact printer fluid to measure impedance values of the printer fluid. The impedance sensor can be connectable to a controller to transmit impedance values of printer fluid to the controller.

Abstract: A microfluidic device can include: a channel; a fluid inlet to pass fluid into the channel from a reservoir; a sensor disposed in the channel; and a pump actuator disposed in the channel apart from the sensor to induce fluid flow into the channel.

Abstract: An inkjet cleaning unit includes a reservoir housing an inkjet wiping fluid that includes a non-wettable material; and an applicator wick fluidly coupled to the reservoir, in which the applicator wick is configured to transport the inkjet wiping fluid from the reservoir to a surface of an inkjet material dispenser. A method for cleaning an inkjet material dispenser includes applying an inkjet wiping fluid from a reservoir housing the inkjet wiping fluid to a surface of the inkjet material dispenser; in which the inkjet wiping fluid includes a non-wettable material; and in which an applicator wick is fluidly coupled to the reservoir to transport the inkjet wiping fluid from the reservoir to the surface of the inkjet material dispenser.

Abstract: Nozzle layouts for printheads are described. In an example, a printhead includes a first set of drop ejectors having orifices with circular bores, and a second set of drop ejectors having orifices with non-circular bores. A processor receives printing data representing an image to be printed to media, and provides firing data to the printhead for activating the drop ejectors. The firing data selects the drop ejectors with the circular bores to print graphic elements of the image and selecting the drop ejectors with the non-circular bores to print textual elements or line elements of the image.

Abstract: Nozzle layouts for printheads are described. In an example, a printhead includes a first set of drop ejectors having orifices with circular bores, and a second set of drop ejectors having orifices with non-circular bores. A processor receives printing data representing an image to be printed to media, and provides firing data to the printhead for activating the drop ejectors. The firing data selects the drop ejectors with the circular bores to print graphic elements of the image and selecting the drop ejectors with the non-circular bores to print textual elements or line elements of the image.

Abstract: A fluid-application mechanism is to cause fluid to be applied onto media. An electrowetting mechanism is to generate an electric field to affect the fluid applied onto the media.

Abstract: A method for improving gloss of a print includes configuring a printing system to deposit ink drops from a plurality of inks in an ink set onto a print surface. During the depositing, the printing system is further configured to control micro-coalescence of the ink drops. The micro-coalescence is controlled by i) depositing the ink drops onto the print surface according to a predefined order of color based upon solids content, ii) adjusting a number of printing passes, iii) adjusting a delay time between the printing passes, and/or iv) depositing different amounts of the ink drops onto the print surface during different printing passes.

Abstract: A fluid-application mechanism is to cause fluid to be applied onto media. An electrowetting mechanism is to generate an electric field to affect the fluid applied onto the media.

Abstract: Example methods, apparatus and articles of manufacture to control gloss quality in printed images are disclosed. A disclosed example apparatus includes a print engine to print a plurality of images for respective ones of a plurality of colors, each image representing a plurality of different print parameter combinations, a scan module to measure a first plurality of light reflectances for respective ones of the plurality of images and the print parameter combinations, and a calibrator to calibrate an operation of the print engine for respective ones of the plurality of colors based on the first plurality of measured light reflectances, the operations of the print engine including at least one of an order of ink application, a rate of ink application, a density of ink application, or an applied amount of gloss enhancer.

Abstract: In one embodiment, a print bar includes: a substrate having a longer part and a shorter part extending along and parallel to the longer part such that each end of the longer part extends past each end of the shorter part; and multiple printhead dies on the longer part of the substrate. In another embodiment, a modular print bar includes a first module including multiple printhead dies joined together end to end and a second module including multiple printhead dies joined together end to end. The second module is lapped together end to end with the first module.

Abstract: Embodiments include forming internal or external extended surface elements on a print-head substrate, at least in part, using a light beam.

Abstract: In one embodiment, a print bar includes a substrate having a longer part and a shorter part extending along and parallel to the longer part such that each end of the longer part extends past each end of the shorter part; and multiple printhead dies on the longer part of the substrate. In another embodiment, a modular print bar includes a first module including multiple printhead dies joined together end to end; and a second module including multiple printhead dies joined together end to end The second module is lapped together end to end with the first module.

Abstract: An inkjet cleaning unit includes a reservoir housing an inkjet wiping fluid that includes a non-wettable material; and an applicator wick fluidly coupled to the reservoir, in which the applicator wick is configured to transport the inkjet wiping fluid from the reservoir to a surface of an inkjet material dispenser. A method for cleaning an inkjet material dispenser includes applying an inkjet wiping fluid from a reservoir housing the inkjet wiping fluid to a surface of the inkjet material dispenser; in which the inkjet wiping fluid includes a non-wettable material; and in which an applicator wick is fluidly coupled to the reservoir to transport the inkjet wiping fluid from the reservoir to the surface of the inkjet material dispenser.

Abstract: Embodiments include forming internal or external extended surface elements on a print-head substrate, at least in part, using a light beam.

Abstract: A method of inkjet printing includes establishing a back pressure corresponding to a desired print mode in a printhead and changing the back pressure in response to changes in print mode. A printing system for printing in a number of distinct print modes includes an inkjet pen having a printhead and a back pressure control unit having multiple back pressure settings. The back pressure is set to a first value when the printing system is operating in a first print mode to a second value when the printing system is operating in a second print mode. In another embodiment, the printing system includes structure for controlling meniscus condition in the printhead nozzles by selectively changing back pressure.

Abstract: One embodiment of an imaging device includes an ink holder adapted for holding ink and an ink flow restriction device positioned within the ink holder, the ink flow restriction device including structure for defining a variable fluid resistance along a length of the ink flow restriction device.