Abstract: An apparatus for developing a latent image recorded on a movable imaging surface, including: a reservoir for storing a supply of developer material including toner particles, said reservoir including a developer material mixing and transport area; a donor member being arranged to receive toner particles from said reservoir and to deliver toner particles to the image surface at locations spaced apart from each other in the direction of movement of the imaging surface thereby to develop the latent image thereon; and a climate system, associated with said reservoir, for maintaining said supply of developer material at a predefined temperature, said climate system includes a cooling element for supplying air to said developer material mixing and transport area, and a heating element positioned in said developer material mixing and transport area, said heating element includes a first heat unit associated with heating an inboard area of said developer material mixing and transport area and a second heat unit assoc