Image forming apparatus

An image forming apparatus comprising:

• a development device including a development container that stores developer containing toner to be supplied to an image carrier, a developer conveying member that is supported in a rotatable manner by the development container, and stirs and conveys the developer so as to circulate the same in a conveyance chamber of the development container, and a developer carrier that faces the image carrier and is supported in a rotatable manner by the development container so as to supply the toner in the conveyance chamber to the image carrier;
• a voltage application unit that applies a development voltage to the developer carrier;
• a current detection unit that detects current flowing between the developer carrier and the image carrier when the development voltage is applied;
• and
• a control unit that controls the development device and the voltage application unit, wherein
• the development device includes a toner collection mechanism having a duct that is connected to the conveyance chamber and allows air in the conveyance chamber to flow through, a filter that is disposed at a connecting part between the duct and the conveyance chamber and collects the toner flowing into the duct from the conveyance chamber, and an exhaust fan that makes the air in the conveyance chamber flow outside via the duct, and
• the control unit changes rotational frequency or operation frequency of the exhaust fan based on the current detected by the current detection unit at non-image forming time.