An image forming unit includes an image carrier, a developer carrier, a development housing, and a guide member. The image carrier forms an electrostatic latent image. The developer carrier is in contact with the image carrier while rotating about a rotation axis and facing the image carrier to develop the electrostatic latent image. The development housing accommodates a developer and rotatably supports the developer carrier at one end with an opening portion that is open to the image carrier. The development housing includes an agitation path in which the developer is agitated and a feed path through which the developer is fed to the developer carrier. The guide member is disposed below the opening portion and includes an inner surface opposing the development housing to form a flow path that guides a current of air produced with rotation of the developer carrier in a direction away from the developer carrier, and to guide a recording medium to the image carrier with an outer surface opposite to the inner surface. Dust contained in the current of air is deposited on the inner surface of the guide member.