Image forming apparatus

An image forming apparatus for forming an image with an electrophotographic process, comprising:

• a drive unit having a capacitative load and driving each part of the apparatus;
• a power source for supplying electric power to the drive unit;
• a switch that is located on a power supply path extending from the power source toward the drive unit, that switches whether or not the electric power is supplied to the drive unit, by bringing the drive unit into conduction or non-conduction depending on the action of a specified part of the image forming apparatus;
• and
• a power supply control circuit that is provided on the power supply path between the switch and the drive unit, that supplies electric power to the drive unit by becoming conductive in conjunction with the conductive state of the switch;
• wherein the power supply control circuit includes:
• a field-effect transistor with its source connected to the power source side of the power supply path, and its drain connected to the second drive unit side of the power supply path;
• a first resistive element connected between the field-effect transistor's gate and source;
• a second resistive element and a capacitative element that are connected in parallel with the first resistive element, and connected with each other in series between the gate and the source.

An image forming apparatus comprising:

• an engine unit for forming an image;
• a drive power source for generating a drive voltage to be supplied to the engine unit;
• an FET that is provided between the engine unit and the drive power source, that switches whether or not the drive voltage is supplied to the engine unit;
• a detector for detecting fluctuation of the drive voltage;
• and
• an FET controller for controlling whether the FET is turned on or off depending on fluctuation of the drive voltage detected by the detector, wherein
• the FET's source is connected to the drive power source, its drain is connected to the engine unit, and its gate is connected to the FET controller, and
• wherein the FET controller includes:
• a first resistive element provided between the source and the gate;
• and
• a second resistive element and a capacitative element connected in parallel with the first resistive element and located between the source and the gate.

An image forming apparatus comprising:

• an engine unit for forming an image;
• a drive power source for generating a drive voltage to be supplied to the engine unit;
• an FET that is provided between the engine unit and the drive power source, that switches whether or not the drive voltage is supplied to the engine unit;
• an FET controller for controlling whether the FET is turned on or off depending on fluctuation of the drive voltage;
• and
• a flag controller for generating a flag when the FET controller turns the FET on;
• wherein if the drive voltage fluctuates when the flag controller has generated the flag and the FET controller has turned the FET on, the FET controller turns the FET off in the state where the flag has been generated.