Patent ID: 8548348

Claim:
A high-voltage output apparatus that outputs a high voltage to a charge member that charges an image bearing member, comprising: a voltage application part that applies a DC voltage to the charge member with a predetermined potential; a current detection part that detects a value of a current flowing in the charge member when the DC voltage is applied to the charge member; an exposure unit which exposes the image bearing member to form an electrostatic latent image on the image bearing member; and a control unit that obtains information of voltage differences between a first DC voltage and a second DC voltage, the first DC voltage being a voltage when a detected current detected by the current detection part reaches a current value that indicates a start of discharge between the image bearing member and the charge member under a condition where the voltage application part applies the DC voltage to the charge member so that the DC voltage is varied on a higher-potential side with regard to the predetermined potential, and the second DC voltage being a voltage when the detected current detected by the current detection part reaches a current value that indicates a start of discharge between the image bearing member and the charge member under a condition where the voltage application part applies the DC voltage to the charge member so that the DC voltage is varied on a lower-potential side with regard to the predetermined potential, wherein the control unit obtains a potential on the image bearing member after the exposure unit exposes the image bearing member based on the information of the voltage differences between the first DC voltage and the second DC voltage.