A printer is configured to provide a jet of extraction gas that extracts a printing fluid from a printing nozzle in the presence of an electric field that accelerates the extracted printing fluid toward a printing substrate. The printer is also configured to selectively turn the electric field and the jet of extraction gas off and on to enable printing in gas-extraction mode, an e-assisted gas-extraction mode, or an e-jet mode. The jet of gas can be provided by a second nozzle concentric with the printing nozzle. A third nozzle can discharge a focusing gas around the extracted printing fluid.

An electrohydrodynamic print head has a plurality of nozzles arranged in a plurality of wells. Extraction electrodes are located around the wells at a level below the nozzles. Further, shielding electrodes are located around the wells at a level below the extraction electrodes. For each well, there are several such shielding electrodes located at different angular positions. This allows to use the shielding electrodes for laterally deflecting the ink after its ejection from the nozzles.

A method includes illuminating a drop with a pulse of light from a light source. A duration of the pulse of light is from about 0.0001 seconds to about 0.1 seconds. The method also includes capturing an image, video, or both of the drop. The method also includes detecting the drop in the image, the video, or both. The method also includes characterizing the drop after the drop is detected. Characterizing the drop includes determining a size of the drop, a location of the drop, or both in the image, the video, or both.

The purpose of the present invention is to prevent the flow of air flowing from the outside of a cover part into the cover part via an ink droplet passing hole as air accompanying printing droplets outflows. An inkjet recording device is provided with: a recording mechanism (printing mechanism) having an ink room 101 that ejects an ink column 107, charging electrodes 103A and 103B that charge ink droplets 106 generated from the ink column 107, and deflection electrodes 105A and 105B that deflect charged ink droplets 106A; and a cover part 118 that has an ink droplet passing hole 117 through which the ink droplets 106A deflected by the deflection electrodes 105A and 105B pass and covers the recording mechanism. The inkjet recording device causes the ink droplets 106A to land onto a recording object 116 that moves relative to a recording head 100 to perform recording. A vent hole 130 is provided in a lateral surface of the cover part 118.

There is provided a printing apparatus including: a head having nozzles aligned in a first direction, a manifold, and a driving element; a first temperature sensor configured to detect, in the manifold, a temperature difference between a temperature of the ink at an upstream in the first direction and a temperature of the ink at a downstream in the first direction; and a controller. The nozzles have a first nozzle and a second nozzle. The controller is configured to execute: causing of the head to perform printing, and performing of position correction of correcting a discharge timing of the ink from the nozzles based on the temperature difference so that a distance between a landing position of the ink discharged from the first nozzle and a landing position of the ink discharged from the second nozzle becomes short in a second direction crossing the first direction.

A printer is configured to provide a stream of extraction gas that extracts a printing fluid from a printing nozzle. An electrode produces an electric field that accelerates the extracted printing fluid toward a printing substrate. The printer can be configured to selectively turn the electric field and the stream of extraction gas off and on to enable printing in a gas-extraction mode, an e-assisted gas-extraction mode, or an e-jet mode. The stream of gas can be provided by a second nozzle concentric with the printing nozzle, and the electrode can be part of the second nozzle. A third nozzle can discharge a focusing gas around the extracted printing fluid.

A fluid ejection device includes a fluid slot, at least one fluid ejection chamber communicated with the fluid slot, a drop ejecting element within the at least one fluid ejection chamber, a fluid circulation channel communicated with the fluid slot and the at least one fluid ejection chamber, and a fluid circulating element communicated with the fluid circulation channel. The fluid circulating element is to provide on-demand circulation of fluid from the fluid slot through the fluid circulation channel and the at least one fluid ejection chamber.

A liquid jetting apparatus includes: a first head chip having first nozzles arranged in a nozzle arrangement direction; a second head chip having second nozzles arranged in the nozzle arrangement direction, and being arranged to overlap at least partially with the first head chip in an orthogonal direction orthogonal to the nozzle arrangement direction; a controller configured to control the first head chip and the second head chip to jet liquid from the first nozzles and the second nozzles; and power sources having different voltages, respectively. Each of the first nozzles and the second nozzles is driven by voltage supplied from one of the power sources, and the first head chip has a first overlapping portion and the second head chip has a second overlapping portion overlapping with the first overlapping portion in the orthogonal direction.

A liquid droplet ejection device includes at least one first liquid droplet ejection unit including a first liquid holding unit and a first tip, the first tip to eject the first liquid in the first liquid holding unit as a first liquid droplet onto an object; at least one second liquid droplet ejection unit including a second liquid holding unit and a second tip, the second tip to eject the second liquid in the second liquid holding unit as a second liquid droplet onto the object; an object holding unit to hold the object; and a driving unit to move the first tip and the second tip in a first direction. An inner diameter of the second tip is larger than an inner diameter of the first tip. The first tip and the second tip are arranged along the first direction. The second tip is arranged behind the first tip.

A fluid ejection device includes a fluid slot, at least one fluid ejection chamber communicated with the fluid slot, a drop ejecting element within the at least one fluid ejection chamber, a fluid circulation channel communicated with the fluid slot and the at least one fluid ejection chamber, and a fluid circulating element communicated with the fluid circulation channel. The fluid circulating element is to provide on-demand circulation of fluid from the fluid slot through the fluid circulation channel and the at least one fluid ejection chamber.