Electric potential measuring device using oscillating device, image forming apparatus, and electric potential measuring method

An electric potential measuring method, comprising the steps of:

• preparing an electric potential measuring device comprising an oscillating body axially supported by a support member such that the oscillating body oscillates about the support member, at least one pair of detection electrodes provided on a surface of the oscillating body with the oscillation axis between the pair of detection electrodes, and a signal detecting portion connected to the detection electrodes for detecting an output signal;
• arranging the electric potential measuring device such that the detection electrodes face an electric potential measuring object;
• constituting the electric potential measuring device such that lines of electric force form the electric potential measuring object reach the detection electrodes at all times while the oscillating body is oscillating;
• varying a distance between one of the detection electrodes and the electric potential measuring object and a distance between the other one of the detection electrodes and the electric potential measuring object by causing the oscillating body to oscillate such that when one of the pair of detection electrodes moves toward the electric potential measuring object, the other one of the pair of detection electrodes moves away from the electric potential measuring object;
• and
• detecting an output signal with the signal detection portion.

An electric potential measuring device, comprising:

• a support member;
• an oscillating body axially supported by the support member such that the oscillating body oscillates about the support member;
• at least one pair of detection electrodes provided on a surface of the oscillating body with the oscillation axis between the pair of detection electrodes;
• a drive portion for varying a distance between one of the detection electrodes and an electric potential measuring object disposed facing the detection electrodes and a distance between the other one of the detection electrodes and the electric potential measuring object by causing the oscillating body to oscillate;
• and
• a signal detecting portion connected to the detection electrodes for detecting an output signal,
• wherein the oscillating body is caused to oscillate such that when one of the pair of detection electrodes moves toward the electric potential measuring object, the other one of the pair of detection electrodes moves away from the electric potential measuring object, and
• wherein lines of electric force from the electric potential measuring object reach the detection electrodes when the detection electrodes are located at a minimum distance and a maximum distance from the electric potential measuring object.

An electric potential measuring method, comprising the steps of:

• preparing an electric potential measuring device comprising an oscillating body axially supported by a support member such that the oscillating body oscillates about the support member, at least one pair of detection electrodes provided on a surface of the oscillating body with the oscillation axis between the pair of detection electrodes, and a signal detecting portion connected to the detection electrodes for detecting an output signal;
• arranging the electric potential measuring device such that the detection electrodes face an electric potential measuring object;
• constituting the electric potential measuring device such that lines of electric force form the electric potential measuring object reach the detection electrodes when the detection electrodes are located at a minimum distance and a maximum distance from the electric potential measuring object;
• varying a distance between one of the detection electrodes and the electric potential measuring object and a distance between the other one of the detection electrodes and the electric potential measuring object by causing the oscillating body to oscillate such that when one of the pair of detection electrodes moves toward the electric potential measuring object, the other one of the pair of detection electrodes moves away from the electric potential measuring object;
• and
• detecting an output signal with the signal detection portion.