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, the reservoir including a developer material mixing and transport area; a donor member being arranged to receive toner particles from the 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 the reservoir, for maintaining the supply of developer material at a predefined temperature, the climate system includes a cooling element for supplying cool air to the developer material mixing and transport area, and a heating element positioned within air path for heating air to predefined temperature.