An image forming apparatus includes an image forming unit to form an image on a recording medium and a treatment-liquid application device to apply a treatment liquid to the medium. The application device includes a conveyance roller to convey the medium, an application roller to apply the liquid to the medium, a squeeze roller to spread the liquid on the application roller to form a thin layer of the liquid on the application roller, and a housing member to retain the application roller and the squeeze roller within the housing member and cover outer circumferential surfaces of the application roller and the squeeze roller. The housing member has an opening to contact the application roller with the conveyance roller through the opening and a storage portion to store the liquid. The housing member is rotatable while retaining the application roller and the conveyance roller within the housing member.