Roland Dg Corporation

Kenji Kawagoe

Keisuke Misawa

Takashi Makinose

A liquid injection device includes a liquid injection head and a controller including a driving signal generator generating a driving signal including, in one liquid drop injection period, a first driving pulse and a second driving pulse, and a driving signal supplier. The first driving pulse maintains the pressure chamber in an expanded state for a time period of about (&#xbd;)&#xd7;Tc; and the second driving pulse starts at a timing that is about n&#xd7;Tc after the start of the first driving pulse, n being an integer satisfying n&#x2265;2, to maintain the pressure chamber in the expanded state for the time period of about (&#xbd;)&#xd7;Tc, and to inject the second liquid drop at a speed higher than, or equal to, a speed at which the first liquid drop is injected.

Liquid ejection device and inkjet recording including the same

A liquid injection device includes a driving circuit supplying, to an actuator, a driving signal including a prior driving pulse and a subsequent driving pulse supplied after the prior driving pulse. Where a speed of a leading tip of a prior liquid pillar injected from the nozzle by the prior driving pulse is V, a speed of a leading tip of a subsequent liquid pillar injected from the nozzle by the subsequent driving pulse is V, a time period from start of the injection of the prior liquid pillar until start of the injection of the subsequent liquid pillar is t, a difference between a time period from the injection of the prior liquid pillar from the nozzle until division of the prior liquid pillar in the case where the prior driving pulse is supplied to the actuator but the subsequent driving pulse is not supplied to the actuator, and the time period t, is t, and a time period from start of the injection of the prior liquid pillar until separation of the prior liquid pillar from the nozzle in the case where the prior driving pulse is supplied to the actuator but the subsequent driving pulse is not supplied to the actuator is t, t&#x2264;tand V&#x2265;V&#xd7;(t/t+1) are satisfied.

Liquid injection device and inkjet printer including the same

A liquid injection device includes a liquid injection head and a controller that generates a driving signal including first through fourth driving pulses in one liquid drop injection period and supplies the driving signal to the liquid injection head. The discharge time period of each of the first and second driving pulses is preferably set to about (&#xbd;)&#xd7;Tc. The start timing of the second driving pulse is preferably set to about m&#xd7;Tc (m&#x2267;1) after the start of the first driving pulse. The second ink drop is preferably set to be injected at a speed of the first ink drop or higher. The start timing of the third driving pulse is preferably set to about (n+(&#xbd;))&#xd7;Tc (n&#x2267;1) after the start of the second driving pulse. The start timing of the fourth driving pulse is preferably set to about p&#xd7;Tc (p&#x2267;2) after the start of the third driving pulse. The fourth ink drop is injected at a speed of the third ink drop or higher.

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Hamamatsu, Japan

Kenji Kawagoe