A developer unit for an electrophotographic image forming device includes a developer roll rotatably mounted on a housing. The developer roll includes a shaft defining a rotational axis and a roll body cylindrically disposed around the shaft to form an outer circumferential surface of the developer roll. An end seal includes a curved rotary seal portion sandwiched between a pocket portion of the housing and the outer circumferential surface of the developer roll, such that an outer circumferential surface of the curved rotary seal portion contacts the pocket portion of the housing and an inner circumferential surface of the curved rotary seal portion contacts the outer circumferential surface of the developer roll. The pocket portion of the housing includes protrusions that contact the outer circumferential surface of the curved rotary seal portion to restrict movement of the end seal along an operative rotational direction of the developer roll.