| 摘要 |
PURPOSE:To uniformize recording density by providing a thermal head with plural heating elements, a detection means to detect the number of heating elements in a fixed region, a variable constant voltage circuit to vary a voltage supplied to a thermal head and a drive circuit to supply a conduction signal to each heating element. CONSTITUTION:A thermal head 1 having plural heating elements receives a constant voltage supply from a variable constant voltage circuit 2, and a conduction signal is supplied from the drive circuit a specified region of each of group ten groups to which plural elements are allocated. Data to be heated is counted by a detection means 4, and the number of data lots every fixed region, i.e. the number of heating elements is sequentially stored into a memory 5. Data on the number of elements every fixed region is sequentially output to the variable constant voltage circuit 2. A constant voltage corresponding to the number of heating elements every fixed region is supplied to the thermal head 1, performing heating and driving at an optimal voltage every region. In other words, when the number of heating elements is small, a low voltage is supplied to the thermal head 1, and when the number is large, a high voltage to the thermal head 1. |
