A film member in a development device can vibrate with respect to an internal wall in the development device. An idler gear in the development device includes a projection and is reciprocally movable between a first position and a second position. The first position is a position where the projection is apart from an end edge of the film member in response to a rotation of a toner supply roller when image formation is performed. The second position is a position where the projection overlaps with the end edge of the film member in response to a reverse rotation of the toner supply roller when image formation is not performed. The projection causes the film member to vibrate by intermittently coming into contact with the end edge of the film member along with a rotation of the idler gear at the second position.