| 摘要 |
PURPOSE:To lengthen the life of an ink ribbon without causing uneven densities of print color by using a system in which ink ribbon is shifted toward the widthwise direction when switched from space to back space or vise versa in such a way as to differentiate the using regions of the ink ribbon. CONSTITUTION:In a printing mode by ribbon shifting, when the tip 1a of a printing head is spaced to the left, the lower half region 3a in the widthwise direction of the ink ribbon 3 is used, and when the tip 1a of the priting head is back-spaced to the right, the ink ribbon 3 is shifted to the widthwise direction in such a way as to use its upper half region 3b. In this way, the using region of the ink ribbon is divided into upper and lower ones by spacing or back- spacing. Also, the speed of the ink ribbon is set up such that the same portion is not used by printing in the same direction. In the case where the ink ribbon is driven in one direction, the speed is set at 1/2 of the speed of the printing head, and in the case where it is driven in both directions, the speed is set preferably at 1/3 or more of the speed of the printing head. |
