1. Field of the Invention
The present invention relates to an ink jet printer having an ink circulation path for circulating ink and a manufacturing method thereof.
2. Description of the Related Art
Ink jet printers are equipped with an ink head of the thermal head type or the piezoelectric conversion element (piezo) type. The ink head discharges ink drops on a recording medium such as paper, a film and the like, to perform recording (printing). Some of such printers have an ink circulation path for circulating ink.
For example, in an inkjet printer disclosed in Japanese Laid-open Patent Publication No. 2001-219580, an ink circulation path is formed with an ink discharge unit, an ink flow volume adjustment room provided above the ink discharge unit, an ink collection container provided below the ink discharge unit, and a pump that sends ink in the ink collection container to the ink flow volume adjustment room form an ink circulation path.
Then, in the ink jet printer disclosed in Japanese Laid-open Patent Publication No. 2001-219580, ink is circulated by flowing the ink into the ink discharge unit by the difference in the vertical positions of the ink flow volume adjustment room and the ink collection container, and pumping ink collected in the ink collection container to the ink flow adjustment room by the pump.
Here, upon delivery (transportation) of an ink jet printer in such a configuration, a meniscus formed in the nozzle hole of the ink discharge unit may be destroyed by shaking or shock, and the nozzle hole may suck in some air.
When the air sucked in from the nozzle hole is trapped in the ink path connecting the ink flow volume adjustment room and the ink discharge unit, the trapped air replaces ink in the ink path. Then, ink stored in the ink flow volume adjustment room eventually runs down to the ink collection container.
Therefore, in Japanese Laid-open Patent Publication No. 2001-219580 mentioned above, an electromagnetic valve is provided in the ink path connecting the ink flow volume adjustment room and the ink discharge unit.