| 摘要 |
PURPOSE:To prevent ununiform printing, by a method wherein when there are dots not to be applied for printing at the start of printing by a thermal head, preheating pulses having such a short pulse duration as not to cause color formation are periodically supplied directly to the dots, thereby preheating the dots to a predetermined temperature. CONSTITUTION:After printing is started, whether each 8, 8 of a multiplicity of dots is to be applied for printing is judged by an MPU 1. When the dot 8, 8 is to be energized for printing, the MPU 1 outputs printing data to a pulse duration controlling circuit 10, which generates printing pulses having an appropriate duration, thereby energizing a head 5. When the dot 8, 8 is not to be applied for printing, the MPU 1 outputs preheating data to the applied controlling circuit 10, which generates preheating pulses having such a duration as not to cause printing, and supplies the pulses to the head 5. When there are dots 8, 8 not to be applied for printing, they are preheated by the preheating pulses. Therefore, when these dots 8, 8 suddenly come to be used for printing, they can reach a printing temperature, so that ununiform printing will not occur due to low temperature. |
