Patent ID: 7740351

Claim:
An ink-jet printing machine comprising: a transfer belt unit including an orbital transfer belt which serves as a transfer path of a printing sheet; a sheet feeding unit configured to feed the printing sheet onto the transfer path; an ink-jet head disposed above the transfer path and configured to perform ink ejection on the printing sheet transferred on the transfer path; a sheet pressing roller disposed across the transfer path between the sheet feeding unit and the ink-jet head, and configured to press a central region of the printing sheet transferred on the transfer path; a detecting unit disposed between the sheet pressing roller and the ink-jet head and away from an upper surface of the transfer belt by a predetermined distance, and configured to detect a deformation of the printing sheet that exceeds the predetermined distance by contacting with a deformed part of the printing sheet; and a guide roller disposed across the transfer path between the detecting unit and the ink-jet head and configured to press the printing sheet transferred on the transfer path; wherein a ratio of a distance between the sheet pressing roller and the detecting unit to a distance between the upper surface of the transfer belt and the detecting unit is approximately equal to a ratio of a distance between the guide roller and the ink-jet head to a distance between the upper surface of the transfer belt and the ink-jet head.