RISO Technologies

A liquid ejection head includes a nozzle plate including a plurality of nozzles through which a liquid is ejected, the nozzles being arranged in a first direction, a plurality of pressure chambers arranged in the first direction and each communicating with a corresponding one of the nozzles, a first common liquid chamber including: a first portion that extends in the first direction and communicates with each of the pressure chambers, and a second portion that is connected to an end of the first portion in the first direction, extends in a second direction orthogonal to the first direction, and is disposed in line with a row of the pressure chambers; and a first damper in the second portion of the first common liquid chamber.

A liquid ejection head includes a nozzle plate having a nozzle through which liquid is ejected, a pressure chamber communicating with the nozzle, an actuator configured to change a volume of the chamber in response to a drive signal, and a drive circuit configured to generate the signal. The drive signal includes two ejection waveforms including first and second ejection waveforms, and a suppression waveform between the ejection waveforms and suppresses residual vibration generated by the first ejection waveform. The second ejection waveform is input at a timing at which vibration generated by the first ejection waveform and vibration generated by the suppression waveform intensify each other. A speed of a droplet ejected by the second ejection waveform is greater than a speed of a droplet ejected by the first ejection waveform.

A liquid ejection head includes a nozzle plate having a nozzle through which liquid is ejected, a pressure chamber communicating with the nozzle, an actuator configured to change a volume of the chamber in response to a drive signal, and a drive circuit configured to generate the signal. The signal includes ejection waveforms for causing the nozzle to eject droplets, and a suppression waveform input between the ejection waveforms and suppresses residual vibration generated by a preceding ejection waveform. An ejection waveform input immediately after the suppression waveform is input at a timing at which vibration generated by the ejection waveform and vibration generated by the suppression waveform intensify each other. A speed of a droplet ejected by the ejection waveform input immediately after the suppression waveform is greater than a speed of a droplet ejected by an ejection waveform input prior to the suppression waveform.

A driving device for a liquid ejection head including an actuator configured to eject liquid stored in a pressure chamber through a nozzle, includes a drive circuit configured to generate a drive signal for the actuator of the liquid ejection head, the drive signal including one or more drop waveforms for ejecting one or more droplets of the liquid through the nozzle. The drive circuit is further configured to arrange the one or more drop waveforms in a rear-justified manner such that an end timing of a final drop waveform is the same among drive waveforms for ejecting different numbers of droplets.

A liquid ejection head includes a nozzle plate formed of a flexible film material and including a plurality of nozzles for ejecting a liquid, and a flow path portion forming a flow path of the liquid that includes: a plurality of pressure chambers respectively communicating with the plurality of nozzles, an individual liquid chamber and a common liquid chamber that communicate with the plurality of pressure chambers. The flow path portion includes a damper portion disposed on a side of the flow path opposite to the nozzle plate, the damper portion being formed of a flexible film material.

A liquid ejection head includes a nozzle, a pressure chamber that communicates with the nozzle and stores a first liquid, an actuator configured to change a volume of the pressure chamber, a manifold unit that forms a first flow path running along the actuator and through which a temperature control liquid flows, a driving IC configured to drive the actuator, and a temperature adjustment structure that includes: a temperature control manifold that forms a second flow path running along the driving IC and through which the temperature control liquid flows, and a pair of temperature control blocks, one of which forms a branching flow path and the other of which forms a merging flow path. A heat conductivity of the pair of temperature control blocks is lower than a heat conductivity of the temperature control manifold.

A device for driving an actuator of a liquid ejection head to eject a liquid, includes a first circuit configured to generate one or more base drive waveforms, and a second circuit configured to generate, based on the one or more base drive waveforms, a multi-drop waveform to be input to the actuator to eject one or more drops of the liquid. The multi-drop waveform includes one or more of: a first ejection waveform, a second ejection waveform having lower ejection efficiency than the first ejection waveform, a third ejection waveform that is a part of the first ejection waveform, and a fourth ejection waveform that is a part of the second ejection waveform.

A liquid ejection head includes a nozzle plate extending in a first direction and having a nozzle for ejecting a liquid, and a plurality of flow path substrates extending in the first direction and each having an opening or a groove by which a pressure chamber communicating with the nozzle and a resistance flow path communicating with the pressure chamber are formed. At least one of the flow path substrates includes a first reinforcing wall portion at a location at which the pressure chamber is formed. In the first direction, a distance between one end of the first reinforcing wall portion that is closer to the nozzle than the other end and an edge of the nozzle that is closest to the one end of the first reinforcing wall portion is 75 µm to 175 µm.

A liquid ejection head includes nozzles for ejecting a liquid, pressure chambers communicating with the nozzles, a supply-side flow path, an ejection-side flow path, and piezoelectric elements. When a viscous resistance of each nozzle is Rn, an inertial resistance of each nozzle is Mn, a meniscus compliance of each nozzle is Cn, viscous and inertial resistances of the supply-side flow path are Rm1 and Mml, viscous and inertial resistances from the supply-side flow path to each nozzle are Rc1 and Mc1, viscous and inertial resistances from each nozzle to the ejection-side flow path are Rc2 and Mc2, and resistance and inertial resistances of the ejection-side flow path are Rm2 and Mm2, and M=Mn+1/(1/Mc1+1/Mc2)+1/(1/Mm1+1/Mm2), R=Rn+1/(1/Rc1+1/Rc2)+1/(1/Rm1+1/Rm2), ω=(M×C<n>)<-1/2>, and γ=R/2/M, 0.2≤γ<2>/ω<2>≤1.0 is satisfied.

A liquid ejection head includes pressure chambers arranged in a first direction, each pressure chamber 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, a bypass flow path connected between, and communicating with, the upstream and downstream common chambers, a bypass resistance flow path that communicates with the bypass flow path, and one or more pressure dampers including a first damper region located upstream side of the bypass resistance flow path and a second damper region located downstream side of the bypass resistance flow path.