| 摘要 |
<p>PURPOSE:To protect clear printing, and obtain an electronic blackboard of a small number of parts at a low cost by a method wherein a black rate judging means, a drive time judging means, and a protective means are provided, and an optimum print driving time corresponding to a black rate judged by a sampling plan is determined and is interrupted temporarily according to a condition of temperature. CONSTITUTION:Black rate judging means 37, 42, 43, judging a black rate of a call data at each specific interval, and drive time judging means 45, 35 judging optimum drive time of a thermal printer based on this judged result are established, and the optimum drive time is automatically controlled by the black rate of the cell data. Therefore, clear printing can be performed irrespective of printing data in one frame being dense or thin. Further, since protective means 71, 48, 49 interrupting printing according to a condition of temperature of the thermal printer are established, printing drive time enough for thick data can be determined without anxiety. Therefore, conventional unclearness caused by limiting vainly the printing drive time is removed.</p> |
