| 摘要 |
PURPOSE:To enable the formation of an image of a contrast with a wide range of ink discharge by employing a plurality of ink jet heads equal in the ink discharge port but different in the length. CONSTITUTION:When the diameters of ink discharge port of a head A and a head B are represented by DA and DB respectively, DA=DB. To differentiate the ink discharge with the same diameter, the length XA of the ink discharge port of the head A and the length XB of ink discharge port of the head B are set to be XAnot equal to XB while XA>XB so as to permit the discharge of a small amount of ink liquid by reducing the ink discharge of the head A. Proper selection of the lengths XA and XB enables the varying of the ink discharge about two times thereby doubling the contrast range. The contrast range can be further expanded by increasing the number of heads different in the length of the ink discharge port. |
