An image forming apparatus includes an image supporter, a development unit, a cleaning unit, a collection unit, and a controller. The collection unit includes a collection path where a developer discharge path for transport of a waste developer from a discharger of the development unit and a toner discharge path for transport of waste toner from the cleaning unit merge with each other, and collects the waste developer including the waste toner and waste carrier. A place of a high flow resistance is formed at least partially at the collection path. If the weight ratio of the waste carrier to the waste toner included in the waste developer in the collection path is less than a predetermined value, the controller performs carrier discharge process of moving the carrier from the development unit to the image supporter and removing and discharging the carrier using the cleaning unit during non-image formation.