RISO Technologies Corporation

A liquid ejection head includes pressure chambers arranged in a first direction and storing liquid, pairs of upstream and downstream flow paths, each pair communicating with a corresponding one of the pressure chambers, an upstream common chamber communicating with the upstream flow paths, an upstream port communicating with the upstream common chamber, a downstream common chamber communicating with the downstream flow paths, a downstream port communicating with the downstream common chamber, and a bypass flow path communicating with the upstream and downstream common chambers. Each of the upstream flow paths is inclined in a direction against a flow of the liquid in the upstream common chamber, and each of the downstream flow paths is inclined in a direction against a flow of the liquid in the downstream common chamber.

According to an embodiment, a liquid dispensing head includes a substrate having a first surface and a piezoelectric member on the first surface of the substrate. A sidewall surface portion of the piezoelectric member is inclined at an obtuse angle with respect to the first surface. A vibration plate is positioned above the piezoelectric member in a first direction orthogonal to the first surface. An electrode wiring portion is on the sidewall surface portion and connected to an electrode wiring pattern on the first surface.

A liquid ejection head includes a nozzle, a pressure chamber that communicates with the nozzle, a volume of the chamber being varied to eject liquid from the nozzle, an actuator configured to vary the volume in response to a drive signal, and a drive circuit configured to generate the signal. The signal includes n ejection waveforms each including an ejection pulse including an expansion portion and a contraction portion. At least one of the ejection waveforms includes a damping pulse that is subsequent to the ejection pulse and includes a contraction portion and an expansion portion. The ejection waveforms include consecutive ejection waveforms that are separated by an intermediate time period that is in a range of 0.2 times or more and 2 times or less a half cycle of a natural vibration period of the liquid in the chamber.

A liquid ejection head includes a nozzle plate including a nozzle, a pressure chamber that is capable of storing liquid and communicates with the nozzle, a volume of the pressure chamber being varied to eject the liquid from the nozzle, an actuator configured to vary the volume of the pressure chamber in response to a drive signal, and a drive circuit configured to generate the drive signal that includes a plurality of ejection waveforms. One of the ejection waveforms follows a preceding ejection waveform after an intermediate time period. The drive circuit is configured to set the intermediate time period based on an ejection speed of the liquid that is 0.2 times or more and 2 times or less of a half cycle of a natural vibration period of the liquid in the pressure chamber.

An inkjet head includes a plurality of actuators each configured to eject ink through a corresponding one of nozzles, the actuators including first actuators corresponding to first nozzles that are enabled to eject ink and second actuators corresponding to second nozzles that are disabled from ejecting ink, a drive circuit configured to drive the actuators in accordance with input data, and a data transfer circuit configured to: acquire first image data associating each of the first nozzles with images to be formed, add, to the first image data, dummy image data associated with the second nozzles, and output the first image data to which the dummy image data has been added to the drive circuit as the input data.

According to one embodiment, a liquid ejection head includes a substrate with an opening through which a first liquid can pass. An actuator is on a first side of the substrate and has a plurality of pressure chambers. A manifold is on a second side of the substrate. The manifold forms a first flow path for a second fluid. The liquid ejection head has first electrode with portions formed on an upper surface of the actuator, a surface on the first side of the substrate, an inner wall of the opening, and a surface on the second side of the substrate in a region outside the first flow path.

A liquid ejecting head includes a piezoelectric member formed of a piezoelectric material. The piezoelectric member has grooves extending lengthwise in a first direction. The grooves separate portions of the piezoelectric member into a plurality of piezoelectric elements spaced from each other in a second direction. A connection portion of the piezoelectric member is under at least a portion of the grooves in a third direction. The connection portion connects the piezoelectric elements to each other. Individual electrodes are on first lateral surfaces of the piezoelectric elements on a first side of the piezoelectric member. A common (shared) electrode is on second lateral surfaces of the piezoelectric elements on a second side of the piezoelectric member. Each groove has a depth in an end portion of the groove on the first side that is deeper than a depth in an end portion of the groove on the second side.

According to one embodiment, a driving device for liquid ejection heads includes a control unit configured to apply a multi-droplet waveform to a liquid ejecting element. The multi-droplet waveform is one of a plurality of preset patterns in which each droplet waveform in the multi-droplet waveform is one of a reference ejection waveform or a minute adjustment waveform. The reference ejection waveform causes a droplet of a nominal reference volume to be ejected by the liquid ejecting element. The minute adjustment waveform causes a droplet of less than the nominal reference volume to be ejected by the liquid ejecting element in variable volume increments.

A liquid ejection head includes pressure chambers arranged in a first direction and respectively communicating with nozzles, each pressure chamber for storing liquid, pairs of upstream and downstream flow paths, each pair communicating with a pressure chamber, the upstream and downstream flow paths of each pair being connected to first and second ends of the corresponding pressure chamber, an upstream common chamber communicating with the upstream flow paths, a downstream common chamber communicating with the downstream flow paths, a bypass flow path communicating with the upstream common chamber at an end of the upstream common chamber in the first direction and the downstream common chamber at an end of the downstream common chamber in the first direction, and a pressure damper provided in the bypass flow path.

A liquid ejection head includes pressure chambers arranged in a first direction and respectively communicating with nozzles, each pressure chamber capable of storing liquid, pairs of upstream and downstream flow paths, each pair communicating with a pressure chamber, an upstream common chamber communicating with the upstream flow paths, a downstream common chamber communicating with the downstream flow paths, and a bypass flow path communicating with the upstream and downstream common chambers. A circulation flow rate of the liquid is greater than or equal to a maximum total ejection flow rate of the liquid ejected from the nozzles. The circulation flow rate is a flow rate at which the liquid flowing through the upstream flow paths to the downstream flow paths when a flow rate of the liquid entering from the upstream port is substantially equal to a flow rate of the liquid exiting through the downstream port.