Image forming apparatus

An image forming apparatus, comprising:

• a developing portion that supplies a toner to a photoreceptor drum on which an electrostatic latent image is formed to visualize the electrostatic latent image;
• a high-voltage substrate that applies developing bias voltage to the developing portion;
• a drive system load that is connected to the high-voltage substrate in parallel;
• and
• a drive system power source that is connected to the high-voltage substrate and the drive system load via an interlock portion for supplying electric power to the high-voltage substrate and the drive system load, wherein
• the high-voltage substrate is provided with a developing positive bias circuit for generating developing positive bias voltage;
• a developing reverse bias circuit for generating developing reverse bias voltage;
• and a capacitor that is equipped in a pre-stage of the developing positive bias circuit, and the developing positive bias circuit is connected to the developing reverse bias circuit in parallel, and the developing positive bias voltage is combined with the developing reverse bias voltage to generate the developing bias voltage, and
• the high-voltage substrate also includes an interruption portion for interrupting a reverse current from the drive system load to the developing reverse bias circuit in a case where the interlock portion is turned off at the time of emergency stop, and when the reverse current is interrupted by the interruption portion, supplies electric power that is accumulated in the capacitor to the developing positive bias circuit and applies the developing positive bias voltage that is generated in the developing positive bias circuit as the developing bias voltage to the developing portion for a given length of time.