Abstract: A liquid ejection head includes an individual channel, a first manifold, a filter, a second manifold, and a bypass path. The individual channel has a nozzle. The first manifold is in fluid communication with the individual channel. The filter is disposed in the first manifold. The second manifold is in fluid communication with the individual channel. The bypass path is positioned across the filter from the individual channel with respect to a direction perpendicular to a surface extending direction of the filter. The bypass path provides fluid communication between the first manifold and the second manifold not via the individual channel.

Abstract: There is provided a liquid discharge head including a channel unit. The channel unit includes: first and second individual channel groups including a plurality of first and second individual channels; two supply manifolds and two return manifolds; and bypass channels communicating with the two supply manifolds or with the two return manifolds. A relationship of |P1|>|P2| is satisfied, wherein P1 is a first pressure of the supply manifold provided commonly for the first individual channel group, P2 is a second pressure of the supply manifold provided commonly for the second individual channel group, ?P1 is a third pressure of the return manifold provided commonly for the first individual channel group, and ?P2 is a fourth pressure of the return manifold provided commonly for the second individual channel group.

Abstract: A liquid ejecting head includes a channel forming body including a plurality of individual channels, a first manifold and a second manifold. The plurality of individual channels includes: a nozzle; a pressure chamber which is arranged to be apart from the nozzle in a first direction; a descender communicating the pressure chamber and the nozzle with each other, and extending in the first direction; a return channel including a first return channel and a second return channel, extending in a direction crossing the first direction, and having one end connected to the descender; and a communicating channel including a first communicating channel, and connecting the other end of the return channel to the second manifold. The first communicating channel connects the first return channel to the second manifold and connects the second return channel to the second manifold.

Abstract: A recording apparatus includes a liquid ejection head, a relative displacement unit configured to cause the liquid ejection head and a recording medium to relatively displace in a relative displacement direction, and a controller. The liquid ejection head has two head units each having nozzles arranged in a nozzle arrangement direction intersecting with the relative displacement direction. The two head units are arranged such that some of the nozzles of the two head units overlap with each other in the relative displacement direction. When a recording command instructing to record an image on a recording medium is an instruction to record a specific image whose length in the nozzle arrangement direction is equal to or less than an arrangement range of the nozzles of the head unit, the controller controls the two head units to cause only one of the two head units to record the specific image.

Abstract: A recording apparatus includes a liquid ejection head having nozzles, a controller, and a signal input part through which a user inputs, to the controller, a setting signal indicating settings related to a grade of a barcode or two-dimensional code. The controller drives the liquid ejection head based on the setting signal input through the signal input part to cause the nozzles to eject liquid to record a barcode or two-dimensional code on a recording medium in the grade corresponding to the setting signal.

Abstract: There is provided a liquid discharge apparatus including: a channel unit having a nozzle surface in which a nozzle is opened; an actuator configured to apply an energy for discharging a liquid from the nozzle; and a controller. Ohnesorge number Oh is in a range from 0.17 to 0.34. The controller is configured to drive the actuator so that a velocity v of the liquid discharged from the nozzle is not more than 8 m/s.

Abstract: A liquid discharge head, includes an individual channel, and first and second common channels. The individual channel includes: a nozzle; a pressure chamber; a connection channel; a first communication channel; and a second communication channel. A first vector is defined such that a starting point and ending point are located on the connection channel, and a second vector is defined such that a starting point and an ending point are located on the second communication channel. A first angle formed by a projection vector of the first vector onto the first plane and a projection vector of the second vector onto the first plane is less than 90°. A second angle formed by a projection vector of the first vector onto the second plane and the second vector is less than 90°.

Abstract: A liquid discharge head includes an individual channel which includes: a nozzle; a pressure chamber; a descender of which one end in the first direction is nearer to the nozzle than the other end; and a second connecting channel connecting a second common channel and the one end of the descender. A central axis of the nozzle is positioned between the second common channel and a central axis of the descender in the second direction. The descender includes a first portion including the one end and a second portion positioned between the pressure chamber and the first portion in the first direction. In an end, of the descender, opposite to the second connecting channel in the second direction, an inner wall defining the one end of the first portion protrudes toward the second connecting channel in the second direction beyond an inner wall defining the second portion.

Abstract: There is provided a liquid discharge head including: first and second common channels extending in a first direction; and a plurality of individual channels each including: a supplying part, a descender part, and a returning part. The returning part includes: a throttle part and a wide part. Each of a plurality of nozzles is located at a position at which each of the plurality of nozzles overlaps with the wide part in a second direction. At a throttle-starting position which is a boundary between the throttle part and the wide part, a length in the second direction of the throttle part and a length in the second direction of the wide part are same.

Abstract: A liquid discharging head includes: a pressure chamber; a descender extending from the pressure chamber in a first direction; a communicating channel extending from the descender in a second direction crossing the first direction; a first return channel and a second return channel connecting the communicating channel and a return manifold; and a nozzle connected to the communicating channel. The first return channel and the second return channel are connected, with respect to the communicating channel, at facing positions, respectively, the facing positions facing each other in a direction orthogonal to the second direction; and the nozzle is provided, in the communicating channel, at a position which is offset from an axis of the descender, and which is sandwiched between a connecting location of the first return channel with respect the communicating channel and a connecting location of the second return channel with respect to the communicating channel.

Abstract: There is provided a liquid discharge head including a channel unit that includes plates stacked on top of each other in a first direction and is formed having individual channels, a first common channel, and a second common channel. The first and second common channels communicate with the individual channels. Each individual channel includes a nozzle, a pressure chamber, a descender, a first throttle channel, and a second throttle channel. The plates include a nozzle plate, a pressure chamber plate, and a first plate formed having a first through hole that constitutes part of the descender. A center portion of the nozzle is positioned at a side opposite to the second throttle channel in the second direction with respect to a center portion of the descender.

Abstract: A liquid discharging apparatus includes: a channel member formed with an individual channel, the individual channel including a nozzle and a pressure chamber; a piezoelectric element arranged in the channel member and facing the pressure chamber, the piezoelectric element being configured to apply pressure to liquid in the individual channel; and a driver configured to apply a driving signal to the piezoelectric element, the driving signal being constructed of a plurality of pulse waveforms, wherein the piezoelectric element is driven in a pull-strike system by one piece of the pulse waveforms such that the pressure chamber is depressurized and then pressurized.

Abstract: There is provided a liquid discharge head including a channel unit. The channel unit includes: first and second individual channel groups including a plurality of first and second individual channels; two supply manifolds and two return manifolds; and bypass channels communicating with the two supply manifolds or with the two return manifolds. A relationship of |P1|>|P2| is satisfied, wherein P1 is a first pressure of the supply manifold provided commonly for the first individual channel group, P2 is a second pressure of the supply manifold provided commonly for the second individual channel group, ?P1 is a third pressure of the return manifold provided commonly for the first individual channel group, and ?P2 is a fourth pressure of the return manifold provided commonly for the second individual channel group.

Abstract: A liquid ejection head includes an individual channel, a first manifold, a filter, a second manifold, and a bypass path. The individual channel has a nozzle. The first manifold is in fluid communication with the individual channel. The filter is disposed in the first manifold. The second manifold is in fluid communication with the individual channel The bypass path is positioned between the individual channel and the filter in a direction in which liquid flows. The bypass path extends from the first manifold. The bypass path provides fluid communication between the first manifold and the second manifold not via the individual channel.

Abstract: A liquid ejection head includes an individual channel, a first manifold, a filter, a second manifold, and a bypass path. The individual channel has a nozzle. The first manifold is in fluid communication with the individual channel. The filter is disposed in the first manifold. The second manifold is in fluid communication with the individual channel The bypass path is positioned across the filter from the individual channel with respect to a direction perpendicular to a surface extending direction of the filter. The bypass path provides fluid communication between the first manifold and the second manifold not via the individual channel.

Abstract: A liquid ejection head includes a manifold configured to store liquid therein, a plurality of ejection channels, and a dummy channel. Each ejection channel communicates with the manifold and is configured to receive liquid from the manifold and eject liquid through a corresponding nozzle thereof open to a nozzle surface. The dummy channel communicates with the manifold and includes a dummy nozzle open to the nozzle surface. The dummy channel further includes a pressure chamber, an actuator configured to apply pressure to liquid in the pressure chamber, a communication passage connecting the manifold to the pressure chamber, and a circulation passage through which the pressure chamber communicates with the manifold. The circulation passage is different from the communication passage and located between the dummy nozzle and the manifold.

Abstract: A liquid ejection head includes a manifold configured to store liquid therein, a plurality of ejection channels, and a dummy channel. Each ejection channel communicates with the manifold and is configured to receive liquid from the manifold and eject liquid through a corresponding nozzle thereof open to a nozzle surface. The dummy channel communicates with the manifold and includes a dummy nozzle open to the nozzle surface. The dummy channel further includes a pressure chamber, an actuator configured to apply pressure to liquid in the pressure chamber, a communication passage connecting the manifold to the pressure chamber, and a circulation passage through which the pressure chamber communicates with the manifold. The circulation passage is different from the communication passage and located between the dummy nozzle and the manifold.

Abstract: An ink-jet printer, including a density detector and a controller, wherein, where successive three ejecting operations to be repeatedly performed on the same predetermined region of a recording medium are defined as first through third ejecting operations in the order of performance, the controller executes: a process for detecting a color density of the predetermined region immediately after attachment of the ink ejected in the second ejecting operation; a process for calculating, based on the detected color density, an estimated density after fixation of the ink ejected in the second ejecting operation; a process for calculating, based on print data, an ideal density after fixation of the ink ejected in the second ejecting operation; and a process for correcting the print data based on a difference between the estimated density and the ideal density, and wherein the ink-jet printer performs the third ejecting operation based on the corrected print data.

Abstract: An ink-jet printer, including a density detector and a controller, wherein, where successive three ejecting operations to be repeatedly performed on the same predetermined region of a recording medium are defined as first through third ejecting operations in the order of performance, the controller executes: a process for detecting a color density of the predetermined region immediately after attachment of the ink ejected in the second ejecting operation; a process for calculating, based on the detected color density, an estimated density after fixation of the ink ejected in the second ejecting operation; a process for calculating, based on print data, an ideal density after fixation of the ink ejected in the second ejecting operation; and a process for correcting the print data based on a difference between the estimated density and the ideal density, and wherein the ink-jet printer performs the third ejecting operation based on the corrected print data.

Abstract: There is provided a piezoelectric actuator, including: first and second piezoelectric layers; a driving electrode arranged between the first and second piezoelectric layers; a second electrode maintained at a predetermined first electrical potential; and a third electrode maintained at a second electrical potential. A neutral plane of the piezoelectric actuator is positioned at a side opposite to the second piezoelectric layer relative to a center plane of the first piezoelectric layer in a direction of stacking of the first and second piezoelectric layers. A first portion of the first piezoelectric layer is sandwiched between the driving electrode and the second electrode, and a second portion of the second piezoelectric layer is sandwiched between the driving electrode and the third electrode. The first and second portions are polarized parallel to the stacking direction such that they are polarized in mutually opposite directions.