Patent ID: 9707772
Date: 2017-07-18
CPC Classifications: B41J

Claim:
1. An inkjet printer comprising: a printing unit with a circulation path and an inkjet head, the printing unit being configured to eject ink through a nozzle of the inkjet head while circulating the ink along the circulation path; a positive pressure space for a positive pressure for circulating the ink along the circulation path to be applied; a negative pressure space for a negative pressure for circulating the ink along the circulation path to be applied; a positive-pressure-side air opening path having one end connected to the positive pressure space and another end communicating with atmosphere; a negative-pressure-side air opening path having one end connected to the negative pressure space and another end communicating with the atmosphere; a positive-pressure-side air opening valve configured to selectively open and close the positive pressure space to the positive-pressure-side air opening path; a negative-pressure-side air opening valve configured to selectively open and close the negative pressure space to the negative-pressure-side air opening path; and a controller configured to, when terminating circulation of the ink in the circulation path, drive the positive-pressure-side air opening valve to open the positive pressure space to the positive-pressure-side air opening path and then drive the negative-pressure-side air opening valve to open the negative pressure space to the negative-pressure-side air opening path, thereby opening the positive pressure space and the negative pressure space to the atmosphere, wherein the controller is configured to determine a time from an opening of the positive-pressure-side air opening valve that opens the positive pressure space to the positive-pressure-side air opening path to an opening of the negative-pressure-side air opening valve that opens the negative pressure space to the negative-pressure-side air opening path, based on a time constant according to a flow path resistance of the positive-pressure-side air opening path and an air capacity of the positive pressure space.