Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for dispensing toners. In one aspect, a toner dispensing system includes a toner container; a cap and valve assembly coupled to the toner container, the cap and value assembly including: a movable valve assembly, the movable valve assembly having a first position and a second position, a toner path, and an air inlet path, where in a first valve assembly position the toner path and the air inlet path are closed, and in a second valve assembly position the toner path and the air inlet path are open; an air assembly including a first air supply coupled to the air path of the cap and valve assembly and a second regulated air supply coupled to the toner container; and a control assembly for controlling the second air supply.