| 摘要 |
PURPOSE:To drive a recording device by low power, to lengthen the life of a heat- sensitive head, and to economize power consumption by using one section of a current controlling means as a switching circuit limiting conduction currents at a value less than the for recording and conducting all picture element current value. CONSTITUTION:Voltage drop corresponding to the number of the recording and energizing of the heat generating resistors R1-R216 of the first group appears at a resistor RL1. The voltage of the resistor RL1 is applied to between an emitter and a base of a transistor QS2 as base voltage in the forward direction, the impedance of the QS2 lowers being in inverse proportion to the voltage of the resistor RL1, and the impedance of a transistor QS1 changes being in inverse proportion to the impedance of the QS2, i.e., corresponding to the voltage of the resistor RL1. That is, the impedance of the transistor QS1 increases in response to the number of the heat generating resistors being recorded and energized. Thus, currents flowing through the transistor QS1 are a fixed value or less, less than the product of the current value of one heat generating resistor in normal color formation recording and the number of recording and energizing, during the power conduction of the heat generating resistors. |
