| 摘要 |
PURPOSE:To effectively suppress noise generated in a direct drive type thermal head, by inserting a series circuit consisting of a resistor and a condenser between a power source line for supplying a drive current to a heat generating element from an external power source and earth. CONSTITUTION:A remote terminal circuit 7 is one connected between a terminal point farthest from an external power source 6 and comprises a series circuit of a resistor R and a condenser C. A near terminal circuit 8 is one connected to the external power source 6, a power source supply line 11 and an earthed line 12 and is formed of an RC series circuit and inductance elements L respectively inserted into the power source supply lines 11, 12 in series. Therefore, generated high frequency noise advances toward both terminals of the power source wiring and the earthed line in a thermal head 1 therethrough but noise advancing to the remote terminal side is consumed as heat energy by the resistor R in the remote terminal circuit 7 without being reflected from the terminal point. On the other hand, noise advancing to the side of the external power source 6 is inhibited in advance by the inductance elements L in the near terminal circuit 8 and also consumed as heat energy by the resistor R. |
