| 摘要 |
PURPOSE:To obtain a heat sensitive recording device characterized by a simple constitution, easy maintenance, and a low cost, in the recording device having a temperature sensor and a recording paper sensor, by using a common signal processing circuit for both sensors, and using a unitary structure. CONSTITUTION:When the temperature of a heat sensitive recording head 1 exceeds a specified range, the resistance value of a thermistor 6a of the temperature sensor 6 which is attached to the recording head 1 is decreased to the value lower than the specified value. Therefore, the voltage of a noninverted input to a differential amplifier 8 becomes lower than the value of the inverted input. Then a control signal of a logic ''0'' expressing abnormal operation appears at an output OUT. A control circuit stops the recording operation. When recording paper 4 is used up, light from a light emitting diode 7a of the recording paper sensor 7 is not inputed to a phototransistor 7b. Therefore the conductivity between the emitter and the collector of the phototransistor 7b is reduced. As a result, the noninverted input of the differential amplifier 8 is decreased, the output OUT becomes a ''0'', and the recording operation is stopped. |
