| 摘要 |
PURPOSE:To improve the durability of an ink ribbon and a thermal head, as well as improving the legibility of a printed surface by making a combination of colors suitable for a CRT display and by converting any of the colors by utilizing a set value to a color suitable for printing when printing is performed. CONSTITUTION:Printing data for one page in yellow, magenta and cyano, respectively, are lap-printed so as to make a color printed page. The printing data from a host device such as a CRT or the like are stored in a frame memory 27 via a control section 26, and are then transferred to a black-rate detection circuit 31, where whether or not the number of dots represented by '1' in the printing data becomes, for instance, 50% or larger of the total dot number is detected for each color. When the detected number is 50% or larger, a white- black conversion instruction signal is sent to a white-black conversion circuit 28. The whiteblack conversion instruction signal is'1', and the printing data for the respective three colors are totally concerted to '0' when they are '1', while they are totally converted to '1' when they are '1'. The load on a thermal head is thus reduced and the automatic color conversion is performed between patterns or figures and the background. |
