| 摘要 |
PURPOSE:To provide the titled circuit capable of being produced in a high yield and being produced and maintained efficiently, by a method wherein a recording voltage impressed on a recording head can be controlled by setting a constant according to the resistance value of a heating resistor. CONSTITUTION:When a main body 1 of a power source is an amplifier with a transfer function W(S), a controlling voltage for a power source voltage is VC=R.x/RXVH=x.VH (wherein R is the resistance of the heating resistor 7; R.x is the resistance between a sliding terminal of a variable resistor 6 and the ground potential; VH is the recording voltage) and VH=(Vref-VC) W(S) (wherein Vref is a reference internal voltage). From both the formulas, VH=Vref/[1/ W(S)+x], wherein 1<<W(S) (for a direct current), so that VH Vref/x. When the value of (x) is set in accordance with the resistance of the heating resistor 7 in a recording part 20, the recording voltage VH can be set appropriately, a constant quantity of electric power is supplied to the resistor 7, and recorded density can be maintained to be constant. |
