| 摘要 |
An electrostatic voltage detecting device includes a detecting electrode (16) for detecting an electrostatic voltage generated by charge on a recording medium, a variable capacitance diode (18) whose capacitance changes according to an output signal applied from the detecting electrode (16), a primary coil (L1) combined with the variable capacitance diode (18) to form a resonance circuit, an oscillator (24) for supplying an oscillating output signal of predetermined frequency to the primary coil (L1), and a secondary coil (L2) inductively coupled with the primary coil (L1). The capacitance of variable capacitance diode (18) changes according to an output voltage applied from the detecting electrode (16) to vary a resonance frequency of the resonance circuit and consequently a voltage induced in the secondary coil (L2). |
