High-voltage power supply for an image forming device

A high-voltage power supply for applying a developing bias to a developing roller of an image forming apparatus, the high-voltage power supply comprising:

• a substrate;
• a developing bias application circuit that is disposed on the substrate, the developing bias application circuit configured to apply a developing bias to the developing roller in accordance with a control voltage that is input therein;
• a developing bias detection circuit that is disposed on the substrate, the developing bias detection circuit configured to detect the developing bias applied to the developing roller;
• a control voltage adjustment circuit that is disposed on the substrate, the control voltage adjustment circuit configured to adjust the control voltage input to the developing bias application unit such that the developing bias detected by the developing bias detection unit approaches a predetermined target value;
• and
• a condensation determination circuit that is disposed on the substrate, the condensation determination circuit configured to determine that condensation is occurred on the substrate when the control voltage is out of a predetermined range and when a changing rate of the control voltage is larger than a predetermined value.