Hitachi Koki Co., Ltd.

Hitachi Printing Solutions, Ltd.

Lee Chahn

Shinya Kobayashi

Takahiro Yamada

Hitoshi Kida

Kunio Satou

Kazuo Shimizu

Yoshikane Matsumoto

Toshitaka Ogawa

An orifice electrode/ink receiving member is attached to an orifice plate that is attached to a recording head module . An ink absorbing member is embedded in a lower surface of the orifice electrode/ink receiving member . A recording ink droplet ejected through an orifice is deflected as needed by an angled electric field and then impinges on a recording sheet to form a recording dot . On the other hand, a refresh ink droplet is deflected by the angled electric field and impinges on the ink absorbing member of the orifice electrode/ink receiving member after flying in a U-turn path. In this configuration, the ink absorbing member provided to the orifice electrode/ink receiving member collects ink, so that there is no need to increase a gap between the recording head module and the recording sheet so much in order to dispose the ink absorbing member , preventing decrease in recording precision and paper jam. Also, it is possible to perform the ink refresh operation using a minimum amount of ink anytime needed without stopping recording operations.

Refresh ink ejection device and inkjet recording device including the refresh ink ejection device

As shown in FIG. ( ), an electric field is generated at timing T at which an ink droplet is divided, end moves the negative ions toward a main ink portion As shown in FIG. ( &prime;), a resultant main ink droplet M has an increased charging amount of &minus;3 q, and a satellite ink droplet S has a decreased charging amount of &minus;6 q. When the main ink droplet M and the satellite ink droplet S have the mass of 1 m and Qs, respectively, then the relative charging amounts of the main ink droplet M and the satellite ink droplet S are both &minus;3. Hence, the deflection amount of the satellite ink droplet S is approximately equal to the deflection amount of the main ink droplet M. Accordingly, the satellite ink droplet S and the rain ink droplet M impact the recording sheet on the same spot or on the extremely close spots, thereby forming a single dot.

Control device controlling deflection amount by redistributing charge within Ink droplet during flight

A back electrode is provided at a rear surface side of a recording sheet . An orifice electrode is attached to an orifice plate of a head module . The orifice electrode , the orifice plate , and ink filling in a nozzle element are electrically connected to the ground. The back electrode has the potential corresponding to that of a charging/deflecting signal. With this configuration, the orifice electrode , a pressure chamber , and the back electrode together generates an inclined electric field at a position a close to a center trajectory . A charged ink droplet is deflected greatly by the inclined electric field , at an early stage of the ink flight, and even greater deflection can be achieved as the flight proceeds.

Charging/deflecting device capable of effectively deflecting ink droplet

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Hitachi, Japan

Lee Chahn