| 摘要 |
PURPOSE:To change an electric current applied to a printing hammer for optimum printing and improve printing quality and the life of an ink ribbon by providing an error detection means to compare outputs of a printing density detection circuit and a reference density generation circuit for determination and a hammer current control circuit to change the current to a printing hammer in accordance with the content of the error detection output. CONSTITUTION:The printing results which are output through printing on a printing paper 28 are detected by a printing density detection circuit 17 and transmitted to an error detection circuit 18. In the meantime, a density value required for predetermined optimum printing is output from a reference printing density generation circuit 16, and transmitted to the error detection circuit 18. The error detection circuit 18 compares the values obtained by the printing density detection circuit 17 with the reference printing density generation circuit 16, and transmits its difference to a hammer current control circuit 19. The hammer current control circuit 19 adds a value such as reducing an electric current supplied to a hammer coil 26, and when the density of printing results printed by the output of the error detection circuit 18 is higher than a reference printing density, adds a value such as increasing the current, while when the density is lower, to an ICONT terminal of a hammer drive circuit 21 respectively. Thus the current supplied to the hammer coil changes. |
