Ulvac, Inc.

Satoshi Shiba

Mitsuru Yahagi

Masao Murata

Takahiro Miyata

Jyunpei Yuyama

Hirofumi Minami

Kazuhiro Musha

Seiichi Satou

The backing pressure of an ink tank is controlled. The ink tank is connected to a pressure control apparatus. The pressure control apparatus has first and second check valves. When the internal pressure of the ink tank becomes smaller than that of outside atmosphere by a first predetermined pressure or more, the first check valve is switched into an open state to connect the outside atmosphere and the ink tank. To the contrary, when the internal pressure of the ink tank becomes larger than that of outside atmosphere by a second predetermined pressure or more, the second check valve is switched to an open state to connect the ink tank with the outside atmosphere. Therefore, the internal pressure of the ink tank is controlled precisely enough to stabilize the meniscus.

Discharge unit and discharge apparatus

The back pressure of an ink tank is controlled. A porous body is arranged inside the ink tank, the lower end of the porous body contacts an ink, and the ink ascends inside the porous body due to a capillary force. The upper end of the porous body is not immersed in the ink, and a maximum ascending force acts upon the ink stored in the ink tank. Therefore, the ink does not leak from a discharge head located lower than the ink tank. Further, because the ink is accumulated under the porous body and the amount of the ink contacting the porous body is small, components of the ink are less susceptible to deterioration.

Discharge device

Growing community of inventors

Chigasaki, Japan

Satoshi Shiba