A development station in an electrostatographic imaging machine impedes the flow of carrier particles out of the development station as the developer moves from an upper to a lower magnetic roll. The development station includes a developer housing, for retaining a quantity of developer having semi-conductive carrier particles and toner particles, a first magnetic roll having a stationary core with at least one magnet and a sleeve having longitudinal grooves that rotates about the stationary core of the first magnetic roll to present developer on one side of the first magnetic roll to the photoreceptor, a second magnetic roll having a stationary core with at least one magnet and a sleeve having longitudinal grooves that rotates about the stationary core of the second magnetic roll to receive developer from the first magnetic roll and present developer on one side of the second magnetic roll to the photoreceptor, the second magnetic roll being vertically displaced from the first magnetic roll so that a gap exists between the first and the second magnetic rolls, and a magnetic seal located in the gap between the first and the second magnetic rolls to impede the outflow of carrier particles from the developer moving from the first magnetic roll to the second magnetic roll.