| 摘要 |
PURPOSE:To prevent the excess heat generation of a thermal head when the signal conductor of a temperature sensing element is disconnected, and to inform an operator of the generation of the trouble quickly by providing a control means adjusting the conduction power of a heating element with a means detecting the disconnection of the signal conductor transmitting detecting signal. CONSTITUTION:A heating resistor array la on the inside is used as heating resistors corresponding to the number of pixels corresponding to one line. Electricity is conducted through the heating resistors by a driver 1b, and the driver 1b is composed of four circuits, the heating resistors are separated into four blocks, and conduction is controlled at every block. Since a thermistor 1e has the negative temperature characteristics of the lowering of a resistance value in response to a temperature rise, voltage corresponding to the temperature T of a thermal head 1 is extracted at the node of the thermistor 1e and a resistor R. The extracted voltage is transformed into a digital signal by an A/D 2a, and input to a micro-computer 6 as detecting voltage (v). The picture information of an FIFO memory 5 is read at every line, and picture-recorded successively. |
