| 摘要 |
PURPOSE:To securely detect a defective contact on an ON/OFF basis between a thermal head and an ink ribbon, by energizing each recording electrode after conduction between a common electrode and each recording electrode is confirmed by a photo-coupler, at the time of recording by bringing an electrothermal type head into contact with an ink ribbon. CONSTITUTION:To perform thermal transfer recording, a thermal head is brought into contact with an ink ribbon 4. In this condition, a voltage +Vcc is applied to a common electrode 2, and a driving transistor Q is turned OFF because a driving signal DR is 'L'. Therefore, when the common electrode 2 and a recording electrode 31 are in perfect contact with the ink ribbon 4, the voltage +Vcc applied to the common electrode 2 is applied to a light- emitting element 21 through the ink ribbon 4, the recording electrode 31 and a resistor R2. In this case, an electric current flowing in the ink ribbon 4 is such a small current as not to melt an ink. The light-emitting element 21 is thus caused to emit light, which is detected by a light-receiving element 22. |
